Digital Identity – next generation

uk: Комп'ютерні науки

description: Loud calls for more privacy, minimization, and data avoidance are a reaction to repeated cases of identity misuse and the ever-growing mining for our identity data. To address these problems (while allowing to fulfill legitimate requirements) is the promise of the concept of “Self Sovereign Identity (SSI)”. The talk will cover —the concept, and the blockchain-based architecture, —the potential impact on business and society, as well as —some real use-cases.

uk: вхід без авторизації


Elliot Ash

type: Person

cs: Informatika

de: Informatik

fi: tietojenkäsittelytiede

uk: Комп'ютерні науки

en: Computer Science

fr: Informatique

da: Datalogi

es: Ciencias de la Computación

nl: Informatica

cs: Technické vědy

de: Ingenieurwissenschaften

fi: tekniikka

uk: Інженерія

en: Engineering Sciences

fr: Ingénierie

da: Ingeniørvidenskab

es: Ingeniería

nl: Engineering

description: This talk introduces some recent lines of research in social science that apply natural language processing to analyze beliefs and attitudes using observational data. When do politicians use more emotion, rather than logic, in their rhetoric? When do judges use notions of economic efficiency, rather than fairness or justice, in their written opinions? What can language tell us about political views or social attitudes?

TIB AV-Portal

type: Service

type: WebContent

type: MediaObject

@language: en

cs: přihlášení není vyžadováno

de: keine Anmeldung erforderlich

uk: вхід без авторизації

en: no login required

nl: geen login vereist

name: Reading Minds with Natural Language Processing

name: Eidgenössische Technische Hochschule Zürich (ETH Zürich)

addressCountry: CH

addressLocality: Zurich

addressRegion: Zurich

type: Organization

cs: Video

de: Video

fi: Video

uk: Відео

en: Video

fr: Vidéo

da: Video

nl: Video

es: Video


uk: Комп'ютерні науки

description: When the storming of the US Capitol was reported earlier this year, some media made a vague allusion to microtargeting. Meanwhile, on the other end of the spectrum, marketers talk of an "atomic bomb". They fear that targeting will be made more difficult after one of the world's largest corporations announced that IDFA (Identifier for Advertisers) would soon be opt-in. Some users are probably not aware of tracking and profiling with IDs like IDFA, AAID, and more conventional cookies or fingerprinting. Perhaps they have not yet become cognisant of the "explosives" in their pockets. An "explosive" analogy may raise some questions: What, if any, is the manipulative potential of psychometric targeting? Could it even promote extremism? Or is it merely used for harmless advertising? After a brief review of tracking and profiling methods, this talk intends to discuss tracking tech trends that followed regulatory measures worldwide. For example, how (un)important or harmful (harmless) comprehensive behavioural profiling is or what we do (not) want to do about it.

uk: вхід без авторизації

name: Tracking Ecosystem Trends: Profiling, Microtargeting... Where Do We Stand?


uk: Комп'ютерні науки

description: Bringing 15 years of experience and over 75 projects in data analytics & AI, Jonas Dischl can tell numerous stories why some projects failed to reach production stage and create additional value. It isn’t the fanciest algorithm that wins – it is the understanding of common pitfalls and human behaviour/ biases on both the data scientists’ and client’s side. This talk explores the lessons learned and dives into how future data scientists can prevent mistakes from reoccurring.

uk: вхід без авторизації

name: How To Fail: The human factor in data science projects


Public Money? Public Code!

uk: Комп'ютерні науки

description: Why is software created using taxpayers’ money not released as Free Software? The goal of the talk is to present the Public Money? Public Code! campaign of the Free Software Foundation Europe. It will quickly recap what free software is, why software procured/developed by the public sector should be released under a free software license and what recent developments in that area have been made in Switzerland.

uk: вхід без авторизації


Mixed Reality with Robots

uk: Комп'ютерні науки

description: Augmented reality (AR) is becoming more and more common these days. Whether it's virtually putting the name of a mountain on its peak or showing a Pokemon in your backyard most people with a smartphone are familiar with the concept of AR by now. This parallel world of augmentation is growing more and more rapidly. With the robotics industry also growing, there is a huge potential in inviting our robotic counterparts to this world of AR. Join us to see how Microsoft is taking on this challenge and let's play fetch with a Boston Dynamic Spot in Mixed Reality.

uk: вхід без авторизації


Innovate on Layer 8

uk: Комп'ютерні науки

description: While the way we handle cyber threats such as cyberattacks or disinformation has advanced significantly in recent years, we still heavily focus on technology, although many of these threats rely on and exploit human factors. Only few people are engaged in finding truly human-centered solutions and in creating motivating learning opportunities that empower people to effectively deal with such challenges in their private and professional life. Thus, we clearly need more innovators that focus on the human side of things! Based on various examples drawn from her experience, Sarah Mühlemann shows how innovating on layer 8 can look like, why it is exciting for people coming from various backgrounds and what challenges they may be facing. Layer 8 is addressed from the perspective of human-relevant cyber threats, such as social engineering attacks or disinformation.

uk: вхід без авторизації


uk: Комп'ютерні науки

description: When implementing a project we must always think about the consequences of our choices. Whenever we decide to go with tight coupling between elements in our software, there is a need to think about the future - what in case we will need to scale? What if our project grows? All in all, it is all about the final success. Can we achieve it?

uk: вхід без авторизації

name: A way to avoid handshakes: How to keep away from tight coupling in your software


uk: Комп'ютерні науки

description: Online credit card transactions are growing quickly, especially in this changed Covid-19 world. What are the steps in an online credit card transaction, and how many different players are involved? I will discuss the technical and security concerns for handling and processing credit card transactions, and how we make it easier for card holders to safely securely go shopping online.

uk: вхід без авторизації

name: What's needed to sell 50'000 tickets online in 10 Minutes: Performance and Security in online transactions


uk: Комп'ютерні науки

description: Are you getting tired of people reporting security issues in your software? Do you think checking the bounds of your buffers is too much work? You want to find bugs in "your" software, but accidentally "misplaced" the source code?Or maybe, the source code was found again, but nobody understands what it is doing? The answer to all of the above questions - and more - is fuzzing! In essence, fuzzing tries to - intelligently and automatically - find bugs in software. In this talk, you will first get to know how fuzzing actually accomplishes that and how to use it for finding bugs. As a direct application of the first part, we will then go over the process of taking the iPhone boot loader, making it runnable on linux and finally being able to fuzz it.

uk: вхід без авторизації

name: An Introduction to Fuzzing and a direct application to the real world


uk: Комп'ютерні науки

description: Machine Learning and Brain Research are closely related fields: artificial neural networks were inspired by biology, and neuroscience is using machine learning to understand the brain. We start with an overview of the fascinating world of brain research and then explore the intersection between neuroscience and machine learning. By covering a few key results from theoretical neuroscience and from machine learning we point out similarities and differences between the brain and computers.

uk: вхід без авторизації

name: Understanding the Brain: Machine Learning meets Neuroscience


de: Physik, Astronomie

fi: fysiikka, tähtitiede

uk: Фізика, Астрономія

en: Physics, Astronomy

fr: Physique, Astronomie

da: Fysik, Astronomi

es: Física, Astronomía

nl: Natuurkunde, Astronomie

uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

en: Information and Library Sciences

de: Mathematik, Naturwissenschaften

uk: Математика, природничі науки

en: Mathematics, Natural Sciences

de: Geisteswissenschaften

uk: Гуманітарні науки

en: Humanities

@language: de

uk: вхід без авторизації

name: Persistent Identifier in Open-Access-Publikationsworkflows

Universitätsbibliothek Bern

addressLocality: Bern

addressRegion: Bern


uk: Фізика, Астрономія

uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

de: Allgemeine und vergleichende Literatur- und Sprachwissenschaft

uk: Загальне та порівняльне літературознавство та мовознавство

en: General and Comparative Literary Studies and Linguistics

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: Scholarly publishing is broken. How do we fix it?


Ein Open Access Monitor für die Schweiz

uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації


uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: Konsortiale Verträge als Beitrag zur Entwicklung von Open Access


uk: Фізика, Астрономія

uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: Werkstattbericht Berlin Universities Publishing


uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

de: Biologie

uk: Біологія

en: Biology

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: Nachgefragt: Erhebung zu Bedürfnissen zur erfolgreichen Transformation des Publikationssystems


uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: OA Monitoring von Transformative Agreements bei Elsevier und Springer Nature


uk: Фізика, Астрономія

uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: Forschungslücken im Bereich Open-Access-Wirkungen


uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: Wie Open-Access-Projekte Kollaboration ermöglichen durch Werkzeuge, Infrastruktur und Wissensvermittlung


uk: вхід без авторизації

name: Electroporation of cell suspension. From Theory to Practice

name: Leibniz Universität Hannover (LUH), Institut für Mehrphasenprozesse (IMP)

addressCountry: DE

addressLocality: Hanover

addressRegion: Lower Saxony

name: Projekt 'Open Education Resources with Ukraine'


uk: вхід без авторизації

name: Electrospraying Technique: Theory and Methods. Part 2


Materials Testing – Light Microscopy

uk: вхід без авторизації

name: Leibniz Universität Hannover (LUH), Institut für Werkstoffkunde (IW)


Materials Testing - Metallography

uk: вхід без авторизації


uk: вхід без авторизації

name: Materials Testing - Scanning Electron Microscopy


uk: вхід без авторизації

name: Materials Testing - Electron Backscatter Diffraction - EBSD -


Materials Testing - X-Ray Diffraction

uk: вхід без авторизації


Materials Testing - Check Points

uk: вхід без авторизації

name: Ukrainian State University of Science and Technology (USUST), Department of metal forming


uk: Комп'ютерні науки

@language: uk

uk: вхід без авторизації

name: Сегментація зображення V: Визначення поліморфних ознак Символьний опис зображення

name: Leibniz Universität Hannover (LUH), Institut für Photogrammetrie und GeoInformation (IPI)


uk: Комп'ютерні науки

uk: вхід без авторизації

name: Сегментація зображення : Визначення регіонів І


Масштабний простір

uk: Комп'ютерні науки

uk: вхід без авторизації


uk: Комп'ютерні науки

uk: вхід без авторизації

name: Отримання зображень Попередня обробка Розрахунок похідних


АНАЛІЗ ЗОБРАЖЕНЬ - Вступ

uk: Комп'ютерні науки

uk: вхід без авторизації


Postprocessing

uk: Комп'ютерні науки

uk: вхід без авторизації


Active Contours - Part II

uk: Комп'ютерні науки

uk: вхід без авторизації


Active Contours - Part I

uk: Комп'ютерні науки

uk: вхід без авторизації


Feature Extraction - Part II

uk: Комп'ютерні науки

uk: вхід без авторизації


Feature Extraction - Part I

uk: Комп'ютерні науки

uk: вхід без авторизації


Region Segmentation II - Part II

uk: Комп'ютерні науки

uk: вхід без авторизації


Region Segmentation II - Part I

uk: Комп'ютерні науки

uk: вхід без авторизації


Region Segmentation I - Part II

uk: Комп'ютерні науки

uk: вхід без авторизації


Region Segmentation I - Part I

uk: Комп'ютерні науки

uk: вхід без авторизації


Edge Segmentation - Part II

uk: Комп'ютерні науки

uk: вхід без авторизації


Edge Segmentation - Part I

uk: Комп'ютерні науки

uk: вхід без авторизації


Point Segmentation - Part IV

uk: Комп'ютерні науки

uk: вхід без авторизації


Point Segmentation - Part III

uk: Комп'ютерні науки

uk: вхід без авторизації


Point Segmentation - Part II

uk: Комп'ютерні науки

uk: вхід без авторизації


Point Segmentation - Part I

uk: Комп'ютерні науки

uk: вхід без авторизації


Scale Space - Part II

uk: Комп'ютерні науки

uk: вхід без авторизації


Scale Space - Part I

uk: Комп'ютерні науки

uk: вхід без авторизації


uk: Комп'ютерні науки

uk: вхід без авторизації

name: Acquisition and Preprocessing - Part III


Acquisition and Preprocessing - Part II

uk: Комп'ютерні науки

uk: вхід без авторизації


Acquisition and Preprocessing - Part I

uk: Комп'ютерні науки

uk: вхід без авторизації


Image analysis - Introduction

uk: Комп'ютерні науки

uk: вхід без авторизації


keywords:
Photoredox catalysis
C-F bond activation
C-S bond cleavage
C-C bond formation
Radical

de: Chemie

fi: kemia

uk: Хімія

en: Chemistry

fr: Chimie

da: Kemi

es: Química

nl: Scheikunde

uk: Математика, природничі науки

description: Recent times have witnessed the robustness of visible-light-mediated transformations due to their mild nature and diverse mode of reactivity. These are generally operative via radical pathways under metal or metal-free conditions, enriching the chemistry to synthesize various molecular architectures. Herein, I will discuss the breaking of C–S and C–F bonds for the generation of C-centred radicals and its application in C–C bond forming reactions using photoredox catalysis and visible light. References [1] a) S. Ghosh, Z.-W. Qu, S. Pradhan, A. Ghosh, S. Grimme, and I. Chatterjee, Angew. Chem. Int. Ed. 2022, doi.org/10.1002/ange.202115272; b) S. Patel, B. Paul, H. Paul, R. Shankhdhar, I. Chatterjee, Chem. Commun., 2022, 58, 4857–4860.

uk: вхід без авторизації

name: Breaking and Making Bonds using Visible Light Photoredox Catalysis

name: Beilstein-Institut zur Förderung der Chemischen Wissenschaften

addressLocality: Frankfurt am Main

addressRegion: Hesse


Materials Testing - Introduction

uk: вхід без авторизації


A reciprocity law for Redei symbols

cs: Matematika

de: Mathematik

fi: matematiikka

uk: Математика

en: Mathematics

fr: Mathématiques

da: Matematik

es: Matemáticas

nl: Wiskunde

uk: Математика, природничі науки

uk: вхід без авторизації

name: Banff International Research Station (BIRS) for Mathematical Innovation and Discovery


uk: Комп'ютерні науки

description: At the start of the year 2022, there was no documentation for the release of Plone 6. Building and testing documentation required unsustainable maintenance of a complex system. Faced with the daunting task of producing documentation for Plone 6 before its release, the community rallied and responded with an enormous volunteer effort. This talk tells that story, describes the impressive result, and reveals the future of Plone 6 documentation.

uk: вхід без авторизації

name: Documenting Plone 6, or how to lead by getting out of the way


A Deep Dive Into Internals Of Volto

uk: Комп'ютерні науки

description: In this talk, we will dive deep into the Volto codebase and understand how all things wire up internally. How does it provide so much flexibility to a developer and how we can leverage more from it? I think that if we know how an underlying technology works we have less pain in the development of any project and a better understanding of the things which we want to achieve using that technology.

uk: вхід без авторизації


uk: Комп'ютерні науки

description: We are not in the docker-world yet, at least not for deploying sites. Last year we had to publish several Volto sites in production and needed some automated way to handle those deployments because Volto's build process takes so time. We have manged to build a CI-CD pipeline using Gitlab-CI and several other tools to release, build and publish volto addons and sites in an automated way. Earlier this year we published a blog-post explaining this process and this talk will be the extended version of the blog-post.

uk: вхід без авторизації

name: How to deploy Volto sites automatically in a no-docker scenarios


Plone 6 Beyond 2022

uk: Комп'ютерні науки

description: The upcoming final release of Plone 6 will provide a stable, battle tested UI architecture to build projects upon and which people already using previous versions of Volto could upgrade easily. Volto 16 will be the LTS version of Plone 6 final. After this milestone, the community should continue evolving and catching up with the ever-changing "modern" JavaScript ecosystem. React 18, modern backend fetching both in client and in Server Side Rendering, newest routing engines, are some of the technology challenges ahead. Other amazing features are in store for the times to come too. The evolution of Volto's UX/UI: Quanta design system. Slots, the evolution of classic portlets. And many more.

uk: вхід без авторизації


uk: Комп'ютерні науки

description: As part of the Erasmus+ project "ITONBOARD", we developed a concept for a Blended Remote Internship with which we broke new ground. Like pieces of a mosaic, we collected pieces from different worlds and thus linked best practice examples from IT companies on the topic of remote work, knowledge about internships in general, internships in the context of Erasmus+, experiences with e-learning and finally scholarships for online student projects. We interviewed CEOs and employees of remote working companies. On the topic of e-learning and blended learning, we conducted interviews with teachers and students in the participating countries. For the scientific support of our concept, we were able to win Prof. Bernd Gössling from the University of Innsbruck, an expert in vocational learning, who drew our attention to important pedagogical aspects.

uk: вхід без авторизації

name: Guidelines for a BLENDED REMOTE INTERNSHIP in IT companies


uk: Комп'ютерні науки

description: We would like to facilitate the work of developers to update and deploy our new versions of applications. So we know that they are used to create eggs and we decide to use the same way to deploy buildout than eggs. It’s the beginning of your journey. In this talk, I will speak at least about Jenkins, Jenkinsfile, Git(hub), zest.releaser, Puppet, Docker and Plone.

uk: вхід без авторизації

name: How we created, deployed and updated over 200 websites at iMio with no downtime.


Inline migration from Plone 4.3 to 6.0

uk: Комп'ютерні науки

description: This is the story of an inline migration of Plone 4.2 to Plone 5.2 on Python2, then Python 3, then Plone 6.

uk: вхід без авторизації


uk: Комп'ютерні науки

description: Bulk & individual control on Volto Content Rules and URL's redirects

uk: вхід без авторизації

name: Introducing Content Rules and URL Management


uk: Комп'ютерні науки

description: As a student at Érico Andrei’s training "Volto and Plone Deployments” during last year’s Plone Conference, I wondered if training-deploy-project could be automated even further: GitHub - training-deploy-project. Upon exploring the Ansible implementation, I created a new branch that automates installation of prerequisites and adds an option for remote deployment of Docker containers: GitHub - training-deploy-project/tree/ansible-fullstack. This session includes a walk-through of the Ansible code including 3 new menu options and 4 new roles. But why stop there? Let’s renew discussion about the GitHub - plone/ansible-playbook and organize a sprint to update the playbook for Plone 6.

uk: вхід без авторизації

name: Extending the Ansible Playbook for Training


uk: Комп'ютерні науки

uk: вхід без авторизації

name: Practical Smart Contract Sharding with Static Program Analysis

name: Eidgenössische Technische Hochschule Zürich (ETH Zürich)


uk: Комп'ютерні науки

uk: вхід без авторизації

name: Incorrectness Logic for Scalable Bug Detection


uk: Комп'ютерні науки

uk: вхід без авторизації

name: Toward Trustworthy and Interpretable Program Synthesis


Supporting Structured Data

uk: Комп'ютерні науки

uk: вхід без авторизації


uk: Комп'ютерні науки

uk: вхід без авторизації

name: Finding bugs in applications while you code them


uk: Комп'ютерні науки

uk: вхід без авторизації

name: A Quest Toward the “Perfect” Optimizing Compiler


Program Synthesis Co-Design

uk: Комп'ютерні науки

uk: вхід без авторизації


uk: Комп'ютерні науки

uk: вхід без авторизації

name: A Decade Verifying LLVM: How to Retrofit Soundness in Industrial Software


uk: Комп'ютерні науки

uk: вхід без авторизації

name: The Quest for Efficient and Trustworthy Systems


Equality Saturation & egg

uk: Комп'ютерні науки

uk: вхід без авторизації


uk: Комп'ютерні науки

uk: вхід без авторизації

name: CommCSL: Proving Information Flow Security for Concurrent Programs using Abstract Commutativity


uk: Комп'ютерні науки

uk: вхід без авторизації

name: A Compiler for Sound Floating-Point using Affine Arithmetic


uk: Комп'ютерні науки

description: Manually indexing documents for subject-based access is a very labour-intensive intellectual process. A machine could perform similar subject indexing much faster. However, an algorithm needs to be trained and tested with examples of indexed documents. Libraries have a lot of training data in the form of bibliographic databases, but often only a title is available, not the full text. We propose to leverage both title-only metadata and, when available, already indexed full text documents to help indexing new documents. To do so, we are developing Annif, an open source tool for automated indexing and classification. After feeding it a SKOS vocabulary and existing metadata, Annif knows how to assign subject headings for new documents. It has a microservice-style REST API and a mobile web app that can analyse physical documents such as printed books. We have tested Annif with different document collections including scientific papers, old scanned books and current e-books, Q&A pairs from an “ask a librarian” service, Finnish Wikipedia, and the archives of a local newspaper. The results of analysing scientific papers and current books have been reassuring, while other types of documents have proved more challenging. The new version currently being developed is based on a combination of existing NLP and machine learning tools including Maui, fastText and Gensim. By combining multiple approaches, Annif can be adapted to different settings. The tool can be used with any vocabulary and with suitable training data, documents in many different languages may be analysed. With Annif, we expect to improve subject indexing and classification processes especially for electronic documents as well as collections that otherwise would not be indexed at all.

uk: вхід без авторизації

name: AUTOMATING LOD - Annif: leveraging bibliogr. metadata for automated subject indexing & classification

name: ZBW - Leibniz-Informationszentrum Wirtschaft

addressLocality: Kiel

addressRegion: Schleswig-Holstein

name: Hochschulbibliothekszentrum des Landes Nordrhein-Westfalen (hbz)


uk: Комп'ютерні науки

description: The study of audio-visual rhetorics of affect scientifically analyses the impact of auditory and visual staging patterns on the perception of media productions as well as the conveyed emotions. By large-scale corpus analysis of TV reports, documentaries and genre-films of the topos “political crisis”, film scientists aim to follow the hypothesis of TV reports drawing on audio-visual patterns in cinematographic productions to emotionally affect viewers. However, localization and description of these patterns is currently limited to micro-studies due to the involved extremely high manual annotation effort. The AdA Project presented here, therefore, pursues two main objectives: 1) creation of a standardized annotation ontology based on Linked Open Data principles and 2) semi-automatic classification of audio-visual patterns. Linked Open Data annotations enable the publication, reuse, retrieval, and visualization of data from film studies based on standardized vocabularies and Semantic Web technology. Furthermore, automatic analysis of video streams allows to speed up the process of extracting audio-visual patterns. Temporal video segmentation, visual concept detection and audio event classification are examples for the application of computer vision and machine learning technologies within this project. The ontology as well as the created semantic annotations of audio-visual patterns are published as Linked Open Data in order to enable reuse and extension by other researchers. The annotation software as well as the extensions for automatic video analysis developed and integrated by the project are published as open source as we envision these tools to be useful for general deep semantic analysis of audio-visual archives.

uk: вхід без авторизації

name: AUTOMATING LOD - Automation and standardization of semantic video annotations for large-scale empirical film studies


uk: Комп'ютерні науки

description: The Linked Data for Libraries Labs (LD4L-Labs) and Linked Data for Production (LD4P) projects have created an RDF editor by involving the catalogers at every stage of a user centered design process. Faced with the challenge of developing an RDF editor which would support the desired data outputs that were loosely defined during ontology development, it became clear application profiles were required as an added layer on top of the formal definitions of the selected ontology terms. Through the lens of two use cases (cataloging LP records and rare monographs) we will discuss how the project involved a blend of catalogers, technologists, and ontologists to build VitroLib, a working prototype editor optimized for specific content types and with integrated lookup services. We will describe findings from cataloger assessment of the search behavior and display of information about entities across datasets from our work on lookup services based on the Questioning Authority gem. Continuing preliminary work discussed at SWIB 2017, we will provide details on the construction of SHACL in support of form building and the translation process from SHACL into configuration required for VitroLib. We will highlight challenges, including examples where SHACL semantics do not translate directly to VitroLib form definitions, the need for extensions to SHACL in support of forms, and the lack of best practices in the nascent SHACL community.

uk: вхід без авторизації

name: USER INTERFACES - Capturing cataloger expectations in an RDF editor: SHACL, lookups and VitroLib


uk: Комп'ютерні науки

description: Libraries and museums around the globe are transforming their catalogs and records into Linked Data to foster linkage and navigation across data silos. This in return significantly enriches their own assets with valuable information stemming from related sources. The result is a large Knowledge Graph of cross-linked resources typically based on standards such as RDF or OWL. However, navigating and querying large graphs is challenging. Sure, many retrieval tasks are best served by standard user interfaces based on forms and fields. Despite that data providers and users often complain about poor tool support for explorative navigation through complex cross-linked library data. In fact, there should be something in between query forms and SQL/SPARQL query syntax. We will discuss tool support for visually analyzing and querying large LOD volumes with the help of example data from museums and the scholarly domain for providers and users. This includes interactive network rendering approaches, faceted search and other visualization paradigms that promise to ad hoc understand, analyze and track graph-based data as a whole. Relevant benchmark criteria in this respect are among others: - Scalability of visualization approach and user orientation (data provider & user) - User guidance during data exploration (data provider & user) - Support in detection of data patterns or flaws to increase data quality (data provider) - Presumed knowledge of the data schema or query languages (user).

uk: вхід без авторизації

name: USER INTERFACES - Connecting the dots of Linked Data of resource collections


uk: Комп'ютерні науки

description: The French national library uses the data.bnf.fr online platform as an interface to disseminate its metadata on the semantic web. Source metadata includes notably, but is not limited to, MARC records to be converted and published as RDF triples, with authority records used as the basis for data.bnf.fr landing pages; the RDF graph is also enriched with alignments with external resources or FRBR relations between internal entities. 2018 is a game changer as a number of works displayed in data.bnf.fr will not be grounded on existing authority records, but will be automatically computed from clusters of bibliographic records. The first corpus for this will be the French textual works from the XXth and XXIst centuries, for which several hundred thousands works will be created. These works will be available as web pages available on the data.bnf.fr public interface, and as RDF data retrievable through the data.bnf.fr SPARQL Endpoint. In the long run, such works will be uploaded as MARC authority records in the main catalog and will comply with the traditional workflow where data.bnf.fr feeds on the BnF catalogue to generate its entities with persistent identifiers and records. In the meantime, the BnF must find answers to a number of questions: - Which data can reliably be used to group together bibliographic records as manifestations of a same work? - Which data can be used from those bibliographic records to compute work-level metadata? - What identifier can we use to identify such works that will not be persistent until they are uploaded in the BnF catalogue? - How can we promote this new metadata and inform its reuse by communicating about their specific nature and limits? The contribution will present methods and tools, steps and questions the data.bnf.fr team encountered in this process.

uk: вхід без авторизації

name: AUTOMATING LOD - Data.bnf.fr as a sandbox for FRBRization


uk: Комп'ютерні науки

description: The digital landscape is evolving very fast. Programming languages as well as softwares once taught in universities and previously well-used among developers may not have the same acceptance among the new generation of developers. Initiatives like the Open Preservation Foundation, and Software Heritage play an important role to document, study and preserve these softwares for future generations. With the creation of Wikidata, the game has now changed. Wikidata provides an easy way to document and describe digital solutions using linked open data. Properties to describe various aspects of programming languages, softwares and mobile applications are being continuously proposed, created and supported by the Wikidata community. It is now increasingly becoming a central hub for linked data sources, thus enabling users to get a complete picture of a given digital artifact, especially for complementary information like dependencies, versions etc. We will present WDProp that can help both new and regular Wikidata contributors to get the latest information on Wikidata supported languages, datatypes, properties as well as community curated projects for finding relevant properties. To further facilitate this process, we also introduce the portal Wikidata for Digital Preservation. This free software portal allows people to quickly contribute to Wikidata. The interface guides users in contributing data in alignment with current data models for the domain of computing.

uk: вхід без авторизації

name: RESEARCH INFRASTRUCTURE - Documenting & preserving programming languages & software in Wikidata


uk: Комп'ютерні науки

description: The university library of Erlangen-Nürnberg harbors not only historic manuscripts and monographs but also valuable paintings, graphics, coins, etc. These cultural objects form part of the university’s rich and heterogeneous collections, ranging from anatomy and archaeology to school history and zoology. Embedded in a broader digitization strategy, the project "Objekte im Netz” develops a documentation and research platform together with a data model based on semantic web technologies and guidelines to provide means to ensure homogeneous data modelling and minimum data quality across the collections. Eventually, they shall provide scholars the means to work on transdisciplinary research questions, too. The tool builds upon the open source WissKI software, a virtual research environment for cultural heritage that natively stores data using RDF. The common data model is implemented as an OWL ontology that extends the CIDOC CRM and acts as the integrating link between the collections, and also to external sources. This presentation will focus on the integration of the university library's metadata of historic graphics: The metadata can be harvested as MARCXML from different systems and has to be transformed into RDF data aligned with the CIDOC CRM. Following a sketch of the general set-up, an outline of the practical integration steps will be given with a discussion of different technical and data mapping approaches, among others a mapping from BIBFRAME to CIDOC CRM. The discussion is accompanied by remarks on challenges and hindrances met so far, like the lack of officially coined URIs and ontology mismatches.

uk: вхід без авторизації

name: RESEARCH INFRASTRUCTURE - Integrating library data in a semantic web research environment for university collections


uk: Комп'ютерні науки

description: Navigating through the peculiar challenges of a third world country could be sort of an art, particularly towards producing quality work in heavily under-funded libraries. With limited financial resources and limited internet connectivity, the University of Ibadan (UI) Library has had to rely on the generosity of organizations, who provide datasets or metadata in various forms (e.g. LOD, MARC, SRU, etc.), to build tools that can support the classification and cataloguing of items especially those published in Nigeria. One of such is the creation of a Search tool using an LOD from the Library of Congress: the LC Subject Headings (LCSH) Dataset. The developers of the University’s Integrated Library System (UIILS) were able to use this dataset to create a Web Service within the UIILS that allows cataloguing staff search through the LCSH entries, even when there is a downtime internet connectivity and access to updated print copies are not possible. This search tool provides the staff with the Classification Number for an item based the subjects they search for. We'll walk through the processes involved from setting up the Apache Jena and Fuseki Server, to generating SPARQL queries from search parameters, processing of query responses, how those responses are displayed to cataloguing staff and how those responses can LINK to other queries.

uk: вхід без авторизації

name: LINKING AUTHORITIES - LCSH subject indexing with LOD in a Nigerian university library


uk: Комп'ютерні науки

description: In recent years, Linked Data became a key technology for organizations in order to publish their data collections on the web and to connect it with other data sources on the web. With the ongoing change in the research infrastructure landscape where an integrated search for comprehensive research information gains importance, organizations are challenged to connect their historically unconnected databases with each other. In an online survey with 337 social science researchers in Germany, we found evidence that researchers are interested in links between information of different types and from different sources. However, in current scientific portals this is often not yet reflected. In this presentation, we present how Linked Open Data technologies can generally be used to build a backend infrastructure for scientific search portals. This backend infrastructure is set as an additional layer between unconnected non-RDF data collections and makes the links between datasets visible and usable for retrieval via a search index. To address occurring heterogeneity with vague links between datasets, a research data ontology is used in addition for representing different versions and aggregations of research datasets. The LOD backend infrastructure is in use at the search portal of GESIS. The in-use application of our approach has been evaluated in this scientific search portal for the social sciences by investigating the benefit of links between different data sources in a user study. The source code of this project is publicly available.

uk: вхід без авторизації

name: RESEARCH INFRASTRUCTURE - Linked Data technologies as backend infrastructure for scientific search portals


uk: Комп'ютерні науки

description: Repositories have traditionally focused on storing content and metadata for use by local applications and services, but this is a poor fit for the world of linked open data. Fedora, the flexible, extensible, open source repository platform, has been designed and implemented as not just a repository but a linked data server. This has been accomplished primarily through alignment with the Linked Data Platform recommendation from the W3C, but Fedora also has a formally specified REST API that aligns with a variety of modern web standards, such as Memento, Web Access Control, and Activity Streams 2.0. This focus on linked data and web standards has allowed Fedora to serve as a reliable repository that also powers web-based linked open data applications. The latest version of Islandora, codenamed CLAW, integrates Fedora with Drupal 8, the popular content management system. CLAW takes full advantage of Fedora’s linked data capabilities while also leveraging Drupal’s powerful network of contributed modules to provide a modern, web-based repository platform that enables linked open data applications. This can be seen in production at the University of Toronto Scarborough (UTSC), where CLAW has been used to build a site that provides Palladio visualizations and exposes a SPARQL endpoint for complex RDF queries. This presentation will provide an overview of the latest versions of Fedora and Islandora CLAW with a focus on the linked data and web-based features and functionality. It will also use the UTSC site as an example of how Fedora can power linked open data applications. (Source code: fcrepo4, CLAW)

uk: вхід без авторизації

name: USER INTERFACES - Powering Linked Open Data applications with Fedora and Islandora CLAW


uk: Комп'ютерні науки

description: In 2001, James Hendler joined Web inventor Tim Berners-Lee and their colleague Ora Lassila in writing an article describing a vision for the Semantic Web. The paper, which appeared in Scientific American, has been widely cited and led to much work in both academia and industry aimed at adding machine-readable text to the Web. Now, nearly 20 years later, Google reports that machine-readable metadata is found on over 40% of their crawl and knowledge graph technology, which also grew from this vision, is now a big business used by major organizations around the world. Also growing out of that vision has been the use of linked data in many applications particularly including collection management in libraries, museums and video archiving applications. However, despite this success, much of the original vision of the Semantic Web remains unrealized. In this talk, he discusses what was in the original vision, what has occurred and, most importantly, what still remains to be done if we are truly to recognize the full potential of the Semantic Web.

uk: вхід без авторизації

name: KEYNOTE - The Semantic Web: vision, reality and revision


uk: Комп'ютерні науки

description: Linked Open Data is usually provided as-is. Institutions make choices how to model the data, including properties, blank nodes and uris, for valid reasons. If you want to combine data, there are generally two options: 1) do a distributed query and inference on the data 2) aggregate the data into a new, single endpoint. Distribution enables the use of all available data structures, aggregation enables more easy-to-use data and better performance. For aggregation it is good practice to do transformations to obtain the needed convenience. We give an overview of the transformation types needed, learned in the AdamNet Library Association project AdamLink, a collaboration of the Amsterdam City Archives, Amsterdam Museum, University of Amsterdam Library, Public Library of Amsterdam and International Institute of Social History. The objective is to create a linked open data infrastructure connecting the member institutions’ collections on the topic of "Amsterdam", targeted at reuse by researchers, teachers, students, creative industry and general public. We discuss the (dis)advantages of creating an aggregation vs. distribution of queries. Every transformation type should solve a distribution problem to be useful. But transformation probably reduces querying-options on the data. We therefore need to get the best trade-off between complexity and usability. An interesting option to investigate is to apply a caching node mechanism, that could combine the best of both worlds. We distinguish 6 types of transformation: Mapping ontologies - Mapping and adding thesauri and authority lists - Mapping and adding object-types - Adding our own statements - Restructuring data - Data-typing. We will illustrate the transformations with real examples. We will also discuss the issues with feeding back the enriched data in the cache or aggregation to the original data sources.

uk: вхід без авторизації

name: AUTOMATING LOD - Transformations for aggregating Linked Open Data


keywords:
Open Science
Good Research Practice
Research Integrity

uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

description: Together we will discuss open science, good scientific practice and research integrity. After all, openness is a pillar for good scientific practice and contributes to research integrity. But how does metadata fit into this?

uk: вхід без авторизації

name: Helmholtz Information and Data Science Academy

name: Metadata as Key?: Open Science, Good Research Practice and Research Integrity


keywords:
Hydrology
remote sensing
Digital Terrain Models
GIS
Earth Observations
Rivers

uk: Комп'ютерні науки

description: On November 30th, the Open-Earth-Monitor project led by OpenGeoHub hosted Giuseppe Amatulli, a research scientist at Yale University. Dr Amatulli is a passionate forester and spatial modeller by training (M.Sc. & PhD in GeoScience and Forestry) and a computer scientist by trade. His research activity is mainly dedicated to spatial modelling, GIS and remote sensing with particular emphasis on the species distribution model, areal distribution and potential shift under climate change conditions, wildland fire occurrence and pattern recognition, and wildfire risk assessment based on human and bio-physical parameters. Streams and rivers drive several processes in hydrology, geomorphology, geography and ecology. A global starized hydrographic network that accurately delineates streams and rivers and their topographic and topological properties is needed for worldwide environmental applications. Using the MERIT Hydro Digital Elevation Model at 90m and by employing a suite of GRASS GIS hydrological modules, we calculated the range-wide upstream flow accumulation and flow direction to delineate a total of 1.6 million drainage basins and extracted globally a total of 726 million unique stream segments with their corresponding sub-catchments. Besides, we computed stream topographic variables comprising stream slope, gradient, length, and curvature attributes as well as stream topological variables to allow for network routing and various stream order classifications. The validation shows that the newly developed Hydrography90m has the highest spatial precision and contains more headwater stream channels compared to three other global hydrographic datasets. More information at https://doi.org/10.5194/essd-14-4525-2022 & https://hydrography.org/

uk: вхід без авторизації

name: Hydrography90m: pushing the boundaries of computational hydrology


uk: Фізика, Астрономія

uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: Academic Article Structure Tips and Tricks

name: State Scientific and Technical Library of Ukraine

addressCountry: UA

addressLocality: Kyiv

addressRegion: Kyiv City


uk: Математика, природничі науки

uk: вхід без авторизації

name: Вимірювання проникності ендотеліального бар’єру кровоносних судин слизової оболонки кишечника в умовах іn vivo >

name: Taras Shevchenko National University of Kyiv

name: Projekt 'Open Education Resources with Ukraine'


uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: How to run an Open Science Lab – Why book sprints, hackathons and other agile formats are important in the context of research data education at TIB


uk: Фізика, Астрономія

uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: “Enabling open science practices in Helmholtz!” – Spotlight from the perspective of a Research Performing Organization


uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: Open science and research assessment reform – A happy marriage?


uk: Фізика, Астрономія

uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: Supporting Ukrainian Open Science. From Short-Term Goals to Long-Term Gains


uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: Research Organization Registry: Open Persistent Identifiers for Affiliations


uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: Introduction to Ukrainian Startup Fund (part 2)


uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: National research e-infrastructure in Croatia


uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: University Open Science Policy. Experience of the Igor Sikorsky Kyiv Polytechnic Institute


Open Science: Opportunity for Ukraine

uk: Комп'ютерні науки

uk: Фізика, Астрономія

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації


uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: Research Assessment Reform: a Trend and a Challenge


uk: Фізика, Астрономія

uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: ORCID's contribution to the open metadata ecosystem


uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: Introduction to Ukrainian Startup Fund (part 1)


uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: An Early-Career Researchers‘ perspective on Open Science and Research Assessment


Open: Our central mission

uk: Фізика, Астрономія

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації


uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: The value dimensions of open science: from open access to public science


uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: On the use of social networks as a prognostic market tool for improving the practice of evaluating scientific research

name: State Scientific and Technical Library of Ukraine


uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: The role of the National Research and Education Network of Ukraine in providing access to global research infrastructures


uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: Automatic processing of literary review by creating ontologies of scientific research


uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: Open innovation as a factor of Ukraine's integration into the European research area


uk: Фізика, Астрономія

uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: Open Science in Europe: two specific examples


uk: Фізика, Астрономія

uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: How data sharing can alleviate reproducibility crisis in natural sciences


uk: Фізика, Астрономія

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: Open access to the Research Infrastructure at the National Academy of Sciences of Ukraine - the current state, problems, and development prospects


uk: Фізика, Астрономія

uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: The second wave of transition on the way to open science


uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: Data Papers provide an Open and FAIR Way to publish Research Data: GreyNet’s Use Case


uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: The geopolitics of scholarly communication: multiple languages and alphabets


uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Гуманітарні науки

uk: вхід без авторизації

name: Persistent identifiers as Open Science Infrastructure


uk: Фізика, Астрономія

uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: Open science in Ukraine: cloud mathematics


uk: Фізика, Астрономія

uk: Комп'ютерні науки

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: Building Ukrainian Current Research Information System URIS


uk: Фізика, Астрономія

uk: Бібліотекознавство, документознавство

uk: Математика, природничі науки

uk: Гуманітарні науки

uk: вхід без авторизації

name: Mechanisms and tools of accelerators of innovative activity within the framework of the Horizon Europe Program


B3 (B-cubed)

keywords: Datacube, satellite images, earth observations, data services, Europe, data, big data, biodiversity

uk: Комп'ютерні науки

description: B3 (B-cubed) stays for Biodiversity Building Blocks for policy and it is an upcoming Horizon Europe project that will use the concept of data cubes to simplify and standardize access to biodiversity data using the Essential Biodiversity Variables framework. These cubes will be used, in conjunction with other environmental data and scenarios, as the basis for models and indicators of past, current and future biodiversity. The overarching goal of the project is to provide easy access to tools in a cloud computing environment, in real-time and on-demand, with state-of-the-art prediction models of biodiversity, that will output models and indicators of biodiversity status and change. At the workshop organized by the Open-Earth-Monitor project in Athens during the EuroGEO 2022, Quentin Groom from the Plantentuin Meise presented the B3 project.

uk: вхід без авторизації


uk: Комп'ютерні науки

description: ENVISION develops and pilot tests innovative tools for the continuous, large scale and uninterrupted monitoring of farm management activities with regard to sustainability, in compliance with the CAP's agri-environmental objectives. At the workshop organized by the Open-Earth-Monitor project in Athens during the EuroGEO 2022, Thanassis Drivas from the National Observatory of Athens (NOA) presented the ENVISION Data Cube for Big Satellite Image Time-Series to support AI-based national-scale agriculture Monitoring.

uk: вхід без авторизації

name: The ENVISION Data Cube for Big Satellite Image Time-Series to support AI based national-scale agriculture Monitoring


FAIRiCUBE

keywords:
Datacube
satellite images
earth observations
data services
Europe, data
big data

uk: Комп'ютерні науки

description: F.A.I.R. Information Cubes – FAIRiCUBE aims to enable players from beyond classic Earth Observation (EO) domains to provide, access, process, and share gridded data and algorithms in a FAIR and TRUSTable manner. This project’s goal is to leverage the power of Machine Learning (ML) operating on multi-thematic datacubes for a broader range of governance and research institutions from diverse fields, which at present cannot easily access and utilize these potent resources. At the workshop organized by the Open-Earth-Monitor project in Athens during the EuroGEO 2022, Stefan Jetschny from the Norwegian Institute for Air Research presented the FAIRiCUBE.

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uk: Комп'ютерні науки

description: The EcoDataCube is an Open Data Portal, a freely-accessible viewer containing gridded layers for Europe at spatial resolutions of 30-m or more. The maps are produced using FOSS4G software solutions, Machine Learning and Open Earth Observation data. The Open Environmental Data Cube for Europe data aim at serving decision-ready layers such as land cover, air quality and pollution, potential natural vegetation and similar and it was part of the Geo-Harmonizer project that ended in 2022. At the workshop organized by the Open-Earth-Monitor project in Athens during the EuroGEO 2022, Leandro Parente from the OpenGeoHub foundation presented the EcoDataCube.eu

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name: EcoDataCube.eu: Open Environmental Data Cube based on GLAD Landsat and Sentinel-2 L2A imagery (10 mins)


keywords:
Open Data
Open Science
remote sensing
GIS
environmental data
data cube
European Green Deal
governance

uk: Комп'ютерні науки

description: AD4GD’s mission is to co-create and shape the European Green Deal Data Space as an open hub for FAIR data and standards-based services that support the key priorities of pollution, biodiversity and climate change. The focus will be on interoperability concepts that bridge the semantic and technology gaps which currently prevent stakeholders and application domains from multi-disciplinary and multi-scale access to data, and which impede the exploitation of processing services, and processing platforms at different levels including Cloud, HPC and edge computing. Joan Maso from Centre de Recerca Ecològica i Aplicacions Forestals (CREAF) showed the AD4GD project at the workshop organized by the Open-Earth-Monitor project in Athens, during the EuroGEO Workshop 2022.

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name: AD4DG: Datacubes for biodiversity in e-shape


Rasthakenverbindung: Einstiegsvideo

description: Dieses Video dient als Einstieg in die Thematik des Rasthakens.

uk: вхід без авторизації


uk: Математика, природничі науки

uk: вхід без авторизації

name: The impact of mountain waves on an idealized baroclinically unstable large-scale flow

name: Banff International Research Station (BIRS) for Mathematical Innovation and Discovery


uk: Математика, природничі науки

uk: вхід без авторизації

name: Geostrophic motions and internal waves in the atmospheric and ocean


uk: Математика, природничі науки

uk: вхід без авторизації

name: Nonlinearity and unsteadiness in deep-ocean lee waves


uk: Математика, природничі науки

uk: вхід без авторизації

name: Flows induced by Internal Waves and Modes


uk: Математика, природничі науки

uk: вхід без авторизації

name: Internal tides at rough topography: impact of Coriolis and topographic steepness on energy transfer to near-inertial waves and dissipation


uk: Математика, природничі науки

uk: вхід без авторизації

name: Near-inertial damping of nearly geostrophic flows: Stimulated loss of balance


uk: Математика, природничі науки

uk: вхід без авторизації

name: Multiscale Modeling of Strongly Stratified Shear Turbulence


Anatomy of the Lee-Side Hydraulic Jump

uk: Математика, природничі науки

uk: вхід без авторизації


uk: Математика, природничі науки

uk: вхід без авторизації

name: Towards a transient gravity wave drag parameterization in atmospheric models


uk: Математика, природничі науки

uk: вхід без авторизації

name: Constraining atmospheric gravity wave parameterizations in climate models


uk: Математика, природничі науки

uk: вхід без авторизації

name: Gravity wave sources in the Southern Hemisphere in a global mesoscale model


uk: Математика, природничі науки

uk: вхід без авторизації

name: Global modeling of internal tides and the internal gravity wave continuum spectrum


uk: Математика, природничі науки

uk: вхід без авторизації

name: Stability of nonlinear gravity waves in the atmosphere


uk: Математика, природничі науки

uk: вхід без авторизації

name: Observations of Mixing from Wind-Driven Internal Waves in an Energetic Mesoscale


uk: Математика, природничі науки

uk: вхід без авторизації

name: Self-Organized Criticality of turbulence in the strongly stratified mixing layer


uk: Математика, природничі науки

uk: вхід без авторизації

name: Dynamics and dispersion in tide-modified barotropic turbulence


uk: Математика, природничі науки

uk: вхід без авторизації

name: Disentangling unbalanced and balanced dynamics in submesoscale lateral dispersion: ... and the pitfalls encountered in trying to do so


uk: Математика, природничі науки

uk: вхід без авторизації

name: The Effects of Convection in Geostrophic Circulation


uk: Математика, природничі науки

uk: вхід без авторизації

name: Rapid Climate Change and Ocean Mixing: Episodic Imbalance of the MOC

name: Banff International Research Station (BIRS) for Mathematical Innovation and Discovery


uk: Математика, природничі науки

uk: вхід без авторизації

name: Spontaneous Generation and Re-absorption of Internal Waves in a Kuroshio Front Simulation


uk: Математика, природничі науки

uk: вхід без авторизації

name: Strongly stratified turbulence in geophysical wakes


uk: Математика, природничі науки

uk: вхід без авторизації

name: Spontaneous inertia-gravity wave emission in the differentially heated rotating annulus experiment


Broadband island wakes

uk: Математика, природничі науки

uk: вхід без авторизації


uk: Математика, природничі науки

uk: вхід без авторизації

name: Quantification of spontaneous imbalance in rotating stratified turbulence


uk: Математика, природничі науки

uk: вхід без авторизації

name: Trickle Up: How Small-Scale Convection Self-Organizes into Large-Scale Structures


uk: Математика, природничі науки

uk: вхід без авторизації

name: The Global Impact of Subgrid-Scale Langmuir Turbulence and Upper Ocean Carbonate Chemistry


uk: Математика, природничі науки

uk: вхід без авторизації

name: Spontaneous and Stimulated Internal Wave Generation


uk: Математика, природничі науки

uk: вхід без авторизації

name: Modeling and parameterization of mean and eddying flow over topography


uk: Математика, природничі науки

description: Glioblastoma (GBM) is the most frequent and lethal malignant brain tumor in adults due to its invasive capability and resistance to conventional therapies. GBM typically shows an heterogenous microenviron- ment including necrotic and hypoxic areas, abnormal vasculature and different tumor cell phenotypes. We will focus on mathematical models based on PDE that try to reproduce this complex system in order to understand it and better predict the tumor behaviour [1, 2]. In addition, we will discuss in-silico simu- lations based on a mathematical model for brain tumor response to the combination of antithrombotic, antioxidants and radiation therapies [3]. Our mathematical results predict a synergistic decrease in tumor volume when both, cytotoxic therapies and antioxidants were applied. In vitro and in vivo results have confirmed this benefit not only in terms of tumor reduction but also in terms of toxicity reduction. Combined mathematical simulations and on-chip validation of malignant cellular structures formation in GBM have confirmed their usability to better understand the tumor behaviour [4, 5]. Considering the promising results, a clinical trial is being designed.

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name: Mathematical predictions for brain tumor response to novel therapies validated by in vivo and in vitro experiments


uk: Математика, природничі науки

description: Diffuse low-grade gliomas are slowly growing tumors. After tens of years, they transform inexorably into more aggressive forms, jeopardizing the patient’s life. Mathematical modeling could help clinicians to have a better understanding of the natural history of these tumors and their response to treatments. We present here different models of these tumors: the first one is discrete and describes the appearance of the first glioma cells and the genesis of a tumor. The second model is continuous and consists in a PDE that describes the evolution of the cell density. This model can describe the natural evolution of gliomas, their response to treatments such as radiotherapy and the changes in their dynamics in pregnant women. The discrete and the continuous models are designed to be close to the biological reality. The results are quantitatively compared with either biological data or clinical data, at the cellular level (histological samples) and at the tissue level (MRI scans).

uk: вхід без авторизації

name: Modeling origin, natural evolution and response to radiotherapy of gliomas


uk: Математика, природничі науки

description: Pharmacokinetics-pharmacodynamics (PK-PD) models are standardly used to assess the availability and effects of a drug. However those models expressed with ordinary differential equations (ODEs) only describe the evolution of the drug concentration with time assuming that all cells receive the same amount and are targetted homogeneously in the same way. In a tumour case however, the cells states and the local cell environment – in terms of oxygenation and acidity – vary depending on the cells location in the tumour (periphery versus core). As a consequence it might prove useful to integrate spatiality in the models in order to get a more accurate evaluation of the drug uptake by the cells. In this presentation, we show how the effects of temozolomide – a pH-dependent drug directed against brain tumours – can be over-evaluated by the standard PK approach. The integration of the spatial component also shows how the healthy tissue might also be affected by the drug and gives a mean to evaluate collateral effects. The model is thus very helpful to highlight the weaknesses of this therapy and to suggest some new means to significantly improve it.

uk: вхід без авторизації

name: On the interest of modelling spatiality of the pharmacokinetics of temozolomide – a drug against brain tumours – towards therapeutic optimization and innovations


uk: Математика, природничі науки

description: In the majority of cancers, secondary tumors (metastases) and associated complications are the main cause of death. To design the best therapy for a given patient, one of the major current challenge is to estimate, at diagnosis, the burden of invisible metastases and the future time of emergence of these, as well as their growth speed. In this talk, I will present the current state of our research efforts towards the establishment of a predictive computational tool for this aim. I will first shortly present the model used, which is based on a physiologically-structured partial differential equation for the time dynamics of the population of metastases, combined to a nonlinear mixed-effects model for statistical representation of the parameters’ distribution in the population. Then, I will show results about the descriptive power of the model on data from clinically relevant ortho-surgical animal models of metastasis (breast and kidney tumors). The main part of my talk will further be devoted to the translation of this modeling approach toward the clinical reality. Using clinical imaging data of brain metastasis from non-small cell lung cancer, several biological processes will be investigated to establish a minimal and biologically realistic model able to describe the data. Integration of this model into a biostatistical approach for individualized prediction of the model’s parameters from data only available at diagnosis will also be discussed. Together, these results represent a step forward towards the integration of mathematical modeling as a predictive tool for personalized medicine in oncology.

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name: Mathematical Modeling and Prediction of Clinical Metastasis


uk: Математика, природничі науки

description: Metastasis — the spread of cancer from a primary to a distant secondary location — is implicated in over 90% of all cancer related deaths. Despite its importance in patient outcome, a full understanding of the metastatic process remains elusive, largely because of the difficulty in studying the phenomenon experimentally. Recent experimental evidence — including the discovery of the so-called ‘pre-metastatic niche’ — has suggested that metastasis may be a more precisely controlled process than previously thought. In particular, it has been suggested that a developing tumor may be able to corrupt, or ‘educate’, infiltrating immune cells and have them switch from cytotoxic to tumor-promoting roles. Such ‘tumor educated’ immune cells can then travel to distant sites and establish favorable conditions for the settlement and growth of circulating tumor cells. In order to investigate the consequences of tumor-mediated immune education on metastatic spread and growth, we have developed an ordinary differential equation model for tumor-immune dynamics in the metastatic context. The model is studied analytically and numerically, with an examination of the effects of tumor education of immune cells on metastatic dormancy and metastatic blow-up.

uk: вхід без авторизації

name: Tumor-Educated Immune Cells Promote Metastatic Growth


uk: Математика, природничі науки

description: Glioblastoma Multiforme (GBM) is a malignant heterogenous cancer in the brain. We propose modeling GBM with heterogeneity in cell phenotypes using a random differential equation version of the reaction-diffusion equation, where the parameters describing diffusion (D) and proliferation (ρ) are random variables. We investigate the ability to perform the inverse problem to recover the probability distributions of D and ρ solely from spatiotemporal data, for a variety of probability distribution functions. We test the ability to perform the inverse problem for noisy synthetic data. We then examine the predicted effect of treatment, specifically, chemotherapy, when assuming such a heterogeneous population and compare with predictions from a homogeneous cell population model.

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name: Estimating Intratumoral Heterogeneity from Spatiotemporal Data


uk: Математика, природничі науки

description: For decades, elucidate the dynamics of the microenvironment of solid tumors has been considered a major research challenge. The fact is that different therapies have not succeeded to eliminate entirely cancer cells in tumors. This resistance feature to anticancer drugs is often attributed to genetic or even epigenetic causes. Another important, but less appreciated cause of this resistance -a possible manifestation of the former, is the geometrical and physical heterogeneity within the tumor microenvironment that leads to marked gradients in the rate of cell proliferation and to regions of hypoxia and acidity, all of which can influence the sensitivity of the tumor cells to drug treatment. There have been different approaches to overcome this resistance, mainly altering solid tumors' microenvironment, for instance, promoting angiogenesis to help the entrance of drugs. Radiation some times is not an option due to the hypoxia in the tumor deep tissue. On the other hand, these physical and geometrical factors have been identified to be responsible of the unsuccessful drug disperse in tumors in some specific time and spatial scales. In this direction, we present an update of our model of drug transport in solid tumors, that quantifies these factors in terms of space-dependent coefficients of the Fokker-Planck equation. The model follows experiments conducted in the Laboratory of Medical Physics and Molecular Imaging of the National Institute for Cancer (INCan) and the Institute of Physics (IFUNAM).

uk: вхід без авторизації

name: Modeling the dynamics of microenvironment of solid tumors


uk: Математика, природничі науки

description: In both normal tissue and disease states, cells interact with one another, and other tissue components using cellular adhesion proteins. These interactions are fundamental in determining tissue fates, and the outcomes of normal development, wound healing and cancer metastasis. Traditionally continuum models (PDEs) of tissues are based on purely local interactions. However, these models ignore important nonlocal effects in tissues, such as long-ranged adhesion forces between cells. For this reason, a mathematical description of cell adhesion had remained a challenge until 2006, when Armstrong et. al. proposed the use of an integro-partial differential equation (iPDE) model. The initial success of the model was the replication of the cell-sorting experiments of Steinberg (1963). Since then this approach has proven popular in applications to embryogenesis (Armstrong et. al. 2009), zebrafish development (Painter et. al. 2015), and cancer modelling (e.g. Painter et. al. 2010, Domschke et. al. 2014, Bitsouni et. al. 2018). While popular, the mathematical properties of this non-local term are not yet well understood. I will begin this talk by outlining, the first systematic derivation of non-local (iPDE) models for adhesive cell motion. The derivation relies on a framework that allows the inclusion of cell motility and the cell polarization vector in s stochastic space-jump process. The derivation's significance is that, it allows the inclusion of cell-level properties such as cell-size, cell protrusion length or adhesion molecule densities into account. In the second part, I will present the results of our study of the steady-states of a non-local adhesion model on an interval with periodic boundary conditions. The significance of the steady-states is that these are observed in experiments (e.g. cell-sorting). Combining global bifurcation results pioneered by Rabinowitz, equivariant bifurcation theory, and the mathematical properties of the non-local term, we obtain a global bifurcation result for the branches of non-trivial solutions. Using the equation’s symmetries the solutions of a branch are classified by the derivative’s number of zeros. We further show that the non-local operator’s properties determine whether a sub or super-critical pitchfork bifurcation occurs. Finally, I want to demonstrate how the equation's derivation from a stochastic random walk can be extended to derive different non-local adhesion operators describing cell-boundary adhesion interactions. The significance is that in the past, boundary conditions for non-local equations were avoided, because their construction is subtle. I will describe the three challenges we encountered, and their solutions.

uk: вхід без авторизації

name: Non-Local Cell Adhesion Models: Derivation, Bifurcations, and Boundary Conditions


uk: Математика, природничі науки

description: The lamellipodium is a thin, sheet-like structure that is found in the propagating front of fast moving cells like fibroblasts, keratocytes, cancer cells, and more. It is a dense network of linear biopolymers of the protein actin, termed actin-filaments. These actin-filaments are highly dynamic structures that participate in a plethora of processes such as polymerization, nucleation, capping, fragmentation, and more. These processes are important for the structure and functionality of the lamellipodium and the motility of the cell. They are, to a large extent, affected by the extracellular environment; for example, the chemical landscape in which the cell of resides and the local composition and architecture of the Extracellular Matrix (ECM), lead to biased motility responses of the cell. When in proximity to each other, they develop cell-cell adhesion via specialized transmembrane proteins of the \textit{cadherin} family. Collectively, they coagulate to clusters of cells that eventually merge to form cell monolayers. We model these phenomena using the Filament Based Lamellipodium Model (FBLM); an anisotropic, two-phase, two-dimensional, continuum model that describes the dynamics the lamellipodium at the level of actin-filaments and their interactions. The model distinguishes between two families (phases) of filaments and includes the interactions between them, as well as between the network of the filaments and the extracellular environment. The FBLM was first proposed in [1] and later extended in [2,4,5]. The FBLM is endowed with a problem specific Finite Element Method (FEM) that we have previously developed in [3]. In this talk we present the basic components of the FBLM and the FEM and focus on a series of simulations reproducing fundamental components of the motility of the cells, such us chemotaxis, haptotaxis, interaction with the environment [3, 4]. We also present our new findings with respect to cell-cell collision and adhesion, as well as the formation of clusters of cells and cell monolayers [5]. To confront the increased computational needs of the monolayer, we have developed a parallel version of our numerical method which we also address in this talk. Literature: [1] D. Oelz, C. Schmeiser. How do cells move? in Cell mechanics: from single scale-based models to multiscale modeling, Chapman and Hall, (2010). [2] A. Manhart, D. Oelz, C. Schmeiser, N. Sfakianakis, An extended Filament Based Lamellipodium: Model produces various moving cell shapes in the presence of chemotactic signals. J. Theor. Biol. (2015). [3] A. Manhart, D. Oelz, C. Schmeiser, N. Sfakianakis. Numerical treatment of the filament based lamellipodium model (FBLM) in Modelling Cellular Systems. (2016) [4] N. Sfakianakis, A. Brunk. Stability, convergence, and sensitivity analysis of the FBLM and the corresponding FEM, Bull. Math. Biol. (2018) [5] N. Sfakianakis, D. Peurichard, C. Schmeiser, and A. Brunk. The FBLM-FEM: from cell-cell adhesion to cluster formation, (in review).

uk: вхід без авторизації

name: The FBLM-FEM: from cell-cell adhesion to the cluster of cells and cell monolayers

name: Banff International Research Station (BIRS) for Mathematical Innovation and Discovery


uk: Математика, природничі науки

description: Acquisition by cancer cells of a plethora of resistance-conferring genetic alterations greatly limits the clinical utility of most anti- cancer drugs. Therefore, there is a need to improve the effective- ness of treatment before mutational-acquired resistance prevails. Relapse is driven by a small subpopulation of residual or ‘‘drug-tolerant’’ cells, which are traditionally called ‘‘minimal residual disease’’ (MRD), that remain viable upon drug exposure. Recent in vitro findings have indicated that the emergence of these per- sisters is unlikely due to mutational mechanisms. A non-mutually exclusive scenario proposes that the drug-tolerant phenotype is transiently acquired by a small pro- portion of cancer cells through non-mutational mechanisms. To gain insights into the biology of MRD, we applied single-cell RNA sequencing to malignant melanoma BRAF mutated cells, and we identified a subpopulation of melanoma cells is tolerant to targeted therapy via metabolic reprogramming. Cancer cells were known to reprogram their metabolic profiles geared toward glycolysis, despite sufficient oxygen available to support oxidative phosphorylation (OXPHOS), a phenomenon known as the Warburg effect. We found that melanoma MRD can switch their metabolic program from glycolysis towards mitochondrial OXPHOS alimented by fatty acid oxidation (FAO), thereby renders the melanoma MRD highly sensitive to FAO inhibition in vitro and in mouse tumor models. This MRD-directed metabolic reprogramming suggests a more clever treatment combination regimen to fight against cancer resistance.

uk: вхід без авторизації

name: Anti- cancer therapy: Blazing the trail with melanoma


uk: Математика, природничі науки

uk: вхід без авторизації

name: Diffusive limits of stochastic velocity jump processes for biological agents


uk: Математика, природничі науки

description: Bike-sharing systems are changing the urban transportation landscape; we have been working with New York City Bike Share (aka Citi Bike), using analytics and optimization to improve the management of their system. Huge rush-hour usage imbalances the system, and in this talk we focus on methods used to mitigate the imbalances that develop. In particular, we will focus on the use of incentives; we have helped guide the development of Bike Angels, which enlists users to make “rebalancing rides”, and we will describe tradeoffs among a number of policies for determining when and where rides should be incentivized, all of which are based on a user dissatisfaction function model of the performance of the system. Motivate, the operator of Citi Bike, has thus far exported this incentive program to Ford GoBike in San Francisco, Bluebikes in Boston, and Capital Bikeshare in DC. The more recent incentive results are joint work with Hangil Chung and Daniel Freund, but the basis for much of the research presented is also joint with Shane Henderson and Eoin O’Mahony.

uk: вхід без авторизації

name: Crowdsourcing Operations: Incentivizing Bike Angels in America


uk: Математика, природничі науки

description: In data-driven inverse optimization an observer aims to learn the preferences of an agent who solves a parametric optimization problem depending on an exogenous signal. Thus, the observer seeks the agent’s objective function that best explains a historical sequence of signals and corresponding optimal actions. We focus here on situations where the observer has imperfect information, that is, where the agent’s true objective function is not contained in the search space of candidate objectives, where the agent suffers from bounded rationality or implementation errors, or where the observed signal-response pairs are corrupted by measurement noise. We formalize this inverse optimization problem as a distributionally robust program minimizing the worst-case risk that the predicted decision (i.e., the decision implied by a particular candidate objective) differs from the agent’s actual response to a random signal. We show that our framework offers rigorous out-of-sample guarantees for different loss functions used to measure prediction errors and that the emerging inverse optimization problems can be exactly reformulated as (or safely approximated by) tractable convex programs when a new suboptimality loss function is used.

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name: Inverse Optimization with Imperfect Information


uk: Математика, природничі науки

description: Robust optimization (RO) has emerged as one of the leading paradigms to efficiently model parameter uncertainty. The recent connections between RO and problems in statistics and machine learning domains demand for solving RO problems in ever more larger scale. However, the traditional approaches for solving RO formulations based on building and solving robust counterparts or the iterative approaches utilizing nominal feasibility oracles can be prohibitively expensive and thus significantly hinder the scalability of RO paradigm. We present a general and flexible iterative framework to solve robust convex optimization problems that is built on a fully online first-order paradigm. In contrast to the existing literature, a key distinguishing feature of our approach is that it requires access to only cheap first-order oracles for the original problem that are remarkably cheaper than pessimization or nominal feasibility oracles, while maintaining the same convergence rates. This, in particular, makes our approach much more scalable and hence preferable in large-scale applications. In the case of strongly convex functions, we also establish a new improved iteration complexity addressing an open question in the literature. Motivated by a robust portfolio optimization problem, we demonstrate the performance of our approach on robust quadratic programs with ellipsoidal uncertainty.

uk: вхід без авторизації

name: Online First-Order Framework for Robust Convex Optimization


uk: Математика, природничі науки

description: Determining optimal policies in dynamic robust optimization is often challenging due to the curse of dimensionality. As a result, many researchers have proposed restricting attention to classes of simpler decision rules (for instance, static or affine), which are computationally tractable and often deliver excellent performance. In this work, we propose a general theory for analyzing the effectiveness of policies in a large class of dynamic robust optimization problems. Through a transformation of the objective function, we provide a geometric characterization for the effectiveness of a policy class, which is helpful in either establishing the policy’s optimality or bounding its sub-optimality gap. Based on this geometric characterization, we recover and generalize several different results on static and affine polices from the literature. Furthermore, our theory establishes interesting connections with the theory of discrete convexity, global concave envelopes, and the integrality gap of mixed integer linear programs.

uk: вхід без авторизації

name: Analyzing Policies in Dynamic Robust Optimization


uk: Математика, природничі науки

description: We provide an exact deterministic reformulation for data-driven chance constrained programs over Wasserstein balls. For individual chance constraints as well as joint chance constraints with right-hand side uncertainty, our reformulation amounts to a mixed-integer conic program. In the special case of a Wasserstein ball with the 1-norm or the ∞-norm, the cone is the nonnegative orthant, and the chance constrained program can be reformulated as a mixed-integer linear program. Using our reformulation, we show that two popular approximation schemes based on the conditional-value-at-risk and the Bonferroni inequality can perform poorly in practice and that these two schemes are generally incomparable with each other.

uk: вхід без авторизації

name: Data-Driven Chance Constrained Programs over Wasserstein Balls


uk: Математика, природничі науки

description: We introduce a distributionally robust maximum likelihood estimation model with a Wasserstein ambiguity set to infer the inverse covariance matrix of a p-dimensional Gaussian random vector from n independent samples. The proposed model minimizes the worst case (maximum) of Stein's loss across all normal reference distributions within a prescribed Wasserstein distance from the normal distribution characterized by the sample mean and the sample covariance matrix. We prove that this estimation problem is equivalent to a semidefinite program that is tractable in theory but beyond the reach of general purpose solvers for practically relevant problem dimensions p. In the absence of any prior structural information, the estimation problem has an analytical solution that is naturally interpreted as a nonlinear shrinkage estimator. Besides being invertible and well-conditioned even for p>n, the new shrinkage estimator is rotation-equivariant and preserves the order of the eigenvalues of the sample covariance matrix. These desirable properties are not imposed ad hoc but emerge naturally from the underlying distributionally robust optimization model. Finally, we develop a sequential quadratic approximation algorithm for efficiently solving the general estimation problem subject to conditional independence constraints typically encountered in Gaussian graphical models.

uk: вхід без авторизації

name: Distributionally Robust Inverse Covariance Estimation: The Wasserstein Shrinkage Estimator


uk: Математика, природничі науки

description: In this work, we identify partial correlation information structures that allow for simpler reformulations in evaluating the maximum expected value of mixed integer linear programs with random objective coefficients. To this end, assuming only the knowledge of the mean and the covariance matrix entries restricted to block-diagonal patterns, we develop a reduced semidefinite programming formulation. In some cases, this lends itself to efficient representations that result in polynomial-time solvable instances, most notably for the distributionally robust appointment scheduling problem with random job durations as well as for computing tight bounds in PERT networks and linear assignment problems. To the best of our knowledge, this is the first example of a distributionally robust optimization formulation for appointment scheduling that permits a tight polynomial-time solvable semidefinite programming reformulation which explicitly captures partially known correlation information between uncertain processing times of the jobs to be scheduled.

uk: вхід без авторизації

name: Exploiting Partial Correlations in Distributionally Robust Optimization


uk: Математика, природничі науки

description: We study the performance of affine policies for two-stage adjustable robust optimization problem under a budget of uncertainty set. This important class of uncertainty sets provides the flexibility to adjust the level of conservatism in terms of probabilistic bounds on constraint violations.

uk: вхід без авторизації

name: On the Optimality of Affine Policies for Budgeted Uncertainty Sets


uk: Математика, природничі науки

description: We consider sequential decision problems where a first action is made prior to seeing any uncertainty (“here-and-now” optimization variable) and then, after uncertainty arrives, one makes a second corrective action that can depend on the observed uncertainty value (“wait-and-see” optimization variable), which is followed by the arrival of yet another uncertain input that closes the process. Given a sample of observations of the uncertainties, we assume one makes a cautious selection of the “here-and-now” and wait-and-see” actions that guards against the worst-case scenarios and asks for the risk that this actions will meet a shortfall in a new out-of-sample case so that the performance will worsen as compared to the expectation constructed from the observations. We present sample complexity results for this setup based on new compression schemes and discuss various extensions and the difficulties therein.

uk: вхід без авторизації

name: Preliminary results on two-stage scenario problems


uk: Математика, природничі науки

description: Cloud computing services are growing at an exponential rate and with it the cost of providing these services. For cost effectiveness, providers need to rely on multi-tenancy and resource sharing among tenants, since statically reserving resources for a tenant is prohibitively expensive. A major consequence of resource sharing is that the performance of one tenant can be adversely affected by resource demands of other co-located tenants. I will talk about the problem of effectively sharing resources such as memory and CPU in multi-tenant settings. Service level agreement (SLA) gives a framework that defines and enforces accountability of the service provider to the tenant even when the resource is not statically reserved on behalf of the tenant. We model the resource allocation problem as an online optimization problem that incorporates a rich variety of SLAs representing the diversity of clientsâ€™ requirements for resources as well as quality of service. We then design easy to implement algorithms that build on classical caching algorithms as well multiplicative weight update methods. The algorithms work under multi-tenant scenarios involving SLAs and overbooking. We use the framework of competitive analysis to analyze the performance of the algorithm. We will also describe results based on experiments that demonstrate the effectiveness of our solution in practice.

uk: вхід без авторизації

name: Resource Allocation Problems in Cloud Computing


uk: Математика, природничі науки

description: For online resource allocation problems, we propose a new demand arrival model where the sequence of arrivals contains both an adversarial component and a stochastic one. Our model requires no demand forecasting; however, due to the presence of the stochastic component, we can partially predict future demand as the sequence of arrivals unfolds. Under the proposed model, we study the problem of the online allocation of a single resource to two types of customers, and design online algorithms that outperform existing ones. Our algorithms are adjustable to the relative size of the stochastic component, and our analysis reveals that as the portion of the stochastic component grows, the loss due to making online decisions decreases. This highlights the value of (even partial) predictability in online resource allocation. We impose no conditions on how the resource capacity scales with the maximum number of customers. However, we show that using an adaptive algorithm—which makes online decisions based on observed data—is particularly beneficial when capacity scales linearly with the number of customers. Our work serves as a first step in bridging the long-standing gap between the two well-studied approaches to the design and analysis of online algorithms based on (1) adversarial models and (2) stochastic ones. Using novel algorithm design, we demonstrate that even if the arrival sequence contains an adversarial component, we can take advantage of the limited information that the data reveals to improve allocation decisions. We also study the classical secretary problem under our proposed arrival model, and we show that randomizing over multiple stopping rules may increase the probability of success. (Based on joint work with Dawsen Hwang (Google) and Patrick Jaillet (MIT).)

uk: вхід без авторизації

name: Online Resource Allocation under Partially Predictable Demand


uk: Математика, природничі науки

description: Traditional multistage stochastic optimization assumes the underlying probability distribution is known. However, in practice, the probability distribution is often not known or cannot be accurately approximated. One way to address such distributional ambiguity is to use distributionally robust optimization (DRO), which minimizes the worst-case expected cost with respect to a set of probability distributions. In this talk, we study multistage convex DRO with a finite set of scenarios. We illustrate that not all but only some scenarios might have an effect on the optimal value, and we formally define this notion for multistage DRO. In particular, we investigate problems where the distributional ambiguity is modeled stagewise by the total variation distance on conditional probability distributions. We show the resulting problem is a multistage risk-averse optimization with nested coherent risk measures formed by a convex combination of the worst-case and conditional value-at-risk. We conduct perturbation analysis with respect to a collection of scenarios being excluded and propose easy-to-check sufficient conditions for effectiveness. We explore effectiveness of scenario paths as well as scenarios conditional on the history of the stochastic process. Computational experiments illustrate the results on finance and energy problems.

uk: вхід без авторизації

name: Effective Scenarios in Multistage Distributionally Robust Optimization


Secondary Market for Demand Uncertainty

uk: Математика, природничі науки

description: In this talk we consider a centralized resource manager whose aim is to regulate multiple paticipants where the participatnts' goals are to purchase resource so as to satisfy uncertain demands. A secondary market mechanism is introduced to mitigate the conservativeness toward demand uncertainty. We analyze the clearing price of the secondary market, show that a unique Nash equlibrium exists in the many player limit and the NE takes the form of a threshold strategy. Moreover, we show that both the social welfare loss and the deviation of the total ordering from the optimum is of O(\sqrt{n}) where n is the number of players. This is significantly better compared with the case of no secondary market, where the social welfare loss and the deviation of the total order are both O(n).

uk: вхід без авторизації


uk: Математика, природничі науки

description: Multi-stage linear optimization is an integral modeling paradigm in supply chain, energy planning, and finance. However, these problems are computationally demanding, and identifying the correlation structure of the uncertainty across stages presents significant challenges. In this talk, we propose a novel data-driven framework for addressing multi-stage linear optimization based on a simple robustification of the data. For this framework, we report several results: 1) We present a general approximation algorithm for finding near-optimal solutions to the proposed framework via techniques from robust optimization. 2) We establish nonparametric convergence guarantees for the proposed framework which are, to the best of our knowledge, the first of their kind for data-driven multi-stage linear optimization with uncertainty that is arbitrarily correlated across stages. 3) We discuss differences and limitations of alternative multi-stage distributionally robust optimization approaches using Wasserstein ambiguity sets. Finally, we demonstrate the practical tractability and near-optimality of the proposed approach on several data-driven multi-stage inventory management problems. This is joint work with Dimitris Bertsimas and Shimrit Shtern.

uk: вхід без авторизації

name: A Data-Driven Approach for Multi-Stage Linear Optimization


uk: Математика, природничі науки

description: An important and challenging class of two-stage linear optimization problems are those without relative-complete recourse, wherein there exists first-stage decisions and realizations of the uncertainty for which there are no feasible second-stage decisions. Previous data-driven methods for these problems, such as the sample average approximation (SAA), are asymptotically optimal but have prohibitively poor performance with respect to out-of-sample feasibility. In this talk, we present a data-driven method for two-stage linear optimization problems without relative-complete recourse which combines (i) strong out-of-sample feasibility guarantees and (ii) general asymptotic optimality. Our method employs a simple robustification of the data combined with a multi-policy approximation. A key contribution of this work is the development of novel geometric insights, which we use to show that the proposed approximation is asymptotically optimal. We demonstrate the benefit of using this method in practice through numerical experiments.

uk: вхід без авторизації

name: Data-Driven Two-Stage Linear Optimization: Feasibility and Approximation Guarantees


Data-Pooling in Stochastic Optimization

uk: Математика, природничі науки

description: Managing large-scale systems often involves simultaneously solving thousands of potentially unrelated stochastic optimization problems, each with limited data. Optimization intuition suggests decoupling these unrelated problems and solving them separately. Statistical intuition, however, suggests that combining the problems via some form of shrinkage may outperform decoupling, but does not offer a concrete non-parametric approach for doing so when solving complex, constrained optimization problems such as vehicle-routing, economic lot-sizing or facility location. We propose a novel data-pooling algorithm that combines both perspectives. Our approach does not require strong distributional assumptions and applies to constrained, possibly non-convex optimization problems. We show that, unlike the classical statistical setting, the potential benefits of data-pooling, in general, depend strongly on the problem structure, and, in some cases, data-pooling offers no benefit. We prove that as the number of problems grows large, our method learns if pooling is necessary and the optimal amount to pool, even if the expected amount of data per problem is fixed and bounded. We further show that pooling offers significant benefits over decoupling when there are many problems, each of which has a small amount of relevant data. We demonstrate the practical benefits of data-pooling using real data from a chain of retail drug stores in the context of inventory management.

uk: вхід без авторизації

name: Banff International Research Station (BIRS) for Mathematical Innovation and Discovery