82 research outputs found

    Content based recommendation in catalogues of multilingual documents

    Get PDF
    A diplomamunka áttkeinti a többnyelvű információs rendszerek és dokumentum ajánlórendszerek működését és új modelleket ajánl

    Video Conference as a tool for Higher Education

    Get PDF
    The book describes the activities of the consortium member institutions in the framework of the TEMPUS IV Joint Project ViCES - Video Conferencing Educational Services (144650-TEMPUS-2008-IT-JPGR). In order to provide the basis for the development of a distance learning environment based on video conferencing systems and develop a blended learning courses methodology, the TEMPUS Project VICES (2009-2012) was launched in 2009. This publication collects the conclusion of the project and it reports the main outcomes together with the approach followed by the different partners towards the achievement of the project's goal. The book includes several contributions focussed on specific topics related to videoconferencing services, namely how to enable such services in educational contexts so that, the installation and deployment of videoconferencing systems could be conceived an integral part of virtual open campuses

    Simple, Interpretable and Stable Method for Detecting Words with Usage Change across Corpora

    Get PDF
    International audienceThe problem of comparing two bodies of text and searching for words that differ in their usage between them arises often in digital humanities and computational social science. This is commonly approached by training word embeddings on each corpus, aligning the vector spaces, and looking for words whose cosine distance in the aligned space is large. However, these methods often require extensive filtering of the vocabulary to perform well, and-as we show in this work-result in unstable, and hence less reliable, results. We propose an alternative approach that does not use vector space alignment, and instead considers the neighbors of each word. The method is simple, interpretable and stable. We demonstrate its effectiveness in 9 different setups, considering different corpus splitting criteria (age, gender and profession of tweet authors, time of tweet) and different languages (English, French and Hebrew)

    Accountable infrastructure and its impact on internet security and privacy

    Get PDF
    The Internet infrastructure relies on the correct functioning of the basic underlying protocols, which were designed for functionality. Security and privacy have been added post hoc, mostly by applying cryptographic means to different layers of communication. In the absence of accountability, as a fundamental property, the Internet infrastructure does not have a built-in ability to associate an action with the responsible entity, neither to detect or prevent misbehavior. In this thesis, we study accountability from a few different perspectives. First, we study the need of having accountability in anonymous communication networks as a mechanism that provides repudiation for the proxy nodes by tracing back selected outbound traffic in a provable manner. Second, we design a framework that provides a foundation to support the enforcement of the right to be forgotten law in a scalable and automated manner. The framework provides a technical mean for the users to prove their eligibility for content removal from the search results. Third, we analyze the Internet infrastructure determining potential security risks and threats imposed by dependencies among the entities on the Internet. Finally, we evaluate the feasibility of using hop count filtering as a mechanism for mitigating Distributed Reflective Denial-of-Service attacks, and conceptually show that it cannot work to prevent these attacks.Die Internet-Infrastrutur stützt sich auf die korrekte Ausführung zugrundeliegender Protokolle, welche mit Fokus auf Funktionalität entwickelt wurden. Sicherheit und Datenschutz wurden nachträglich hinzugefügt, hauptsächlich durch die Anwendung kryptografischer Methoden in verschiedenen Schichten des Protokollstacks. Fehlende Zurechenbarkeit, eine fundamentale Eigenschaft Handlungen mit deren Verantwortlichen in Verbindung zu bringen, verhindert jedoch, Fehlverhalten zu erkennen und zu unterbinden. Diese Dissertation betrachtet die Zurechenbarkeit im Internet aus verschiedenen Blickwinkeln. Zuerst untersuchen wir die Notwendigkeit für Zurechenbarkeit in anonymisierten Kommunikationsnetzen um es Proxyknoten zu erlauben Fehlverhalten beweisbar auf den eigentlichen Verursacher zurückzuverfolgen. Zweitens entwerfen wir ein Framework, das die skalierbare und automatisierte Umsetzung des Rechts auf Vergessenwerden unterstützt. Unser Framework bietet Benutzern die technische Möglichkeit, ihre Berechtigung für die Entfernung von Suchergebnissen nachzuweisen. Drittens analysieren wir die Internet-Infrastruktur, um mögliche Sicherheitsrisiken und Bedrohungen aufgrund von Abhängigkeiten zwischen den verschiedenen beteiligten Entitäten zu bestimmen. Letztlich evaluieren wir die Umsetzbarkeit von Hop Count Filtering als ein Instrument DRDoS Angriffe abzuschwächen und wir zeigen, dass dieses Instrument diese Art der Angriffe konzeptionell nicht verhindern kann

    Three Essays on Assortment Planning in Omni-Channel Retail Supply Chains

    Get PDF
    In omni-channel retail systems, comprising an online sales website and brick-and-mortar (physical) stores, a physical store typically faces limited shelf-space capacity, while capacity is not an issue for the online channel. Consequently, a crucial aspect of such retail systems is to choose a subset of products present online for showcasing in the physical store (i.e., assortment planning). In my first research stream, I investigate the omni-channel assortment problem when product returns are allowed. Assortment decisions influence product returns, as showcased products provide information to online shoppers who visit the physical store. Therefore, although product returns can be a factor for profit loss, effective assortment planning can mitigate the returns’ adverse impact and optimize profitability. My results indicate that even with sufficient capacity, showcasing all products in the physical store may not be optimal. Additionally, retailers generally fare better when customers undervalue hidden attribute levels. In my second research stream, I explore a decentralized retail supply chain (RSC) comprising an online channel managed by a manufacturer setting wholesale prices, and an independent retailer managing the physical store and making assortment decisions. As a benchmark, I examine a centralized setting where both channels are under a central authority aiming to maximize overall profit. My findings show fundamental differences in optimal centralized and decentralized assortments, indicating inefficiency in the decentralized approach. I propose scope contracts for coordination, wherein the manufacturer offers discounts on wholesale prices for products with specific attribute levels, incentivizing the retailer to adopt the centralized assortment. The scope contracts ensure both parties' profitability and coordinate the RSC. In the third stream, I suppose that the magnitude of inaccuracy in online assessment of products due to the lack of physical encounter is unknown to the RSC parties, and they make decisions with asymmetric information. I investigate the assortment and wholesale price decisions along with profit regrets. My findings under the decentralized setting indicate that while both parties cannot fare better simultaneously, each party can be advantaged under certain conditions. Under the centralized setting, when supposing accurate online assessments, showcasing an assortment of the highest utility attribute levels possibly minimizes system-wide regret

    IDEAS-1997-2021-Final-Programs

    Get PDF
    This document records the final program for each of the 26 meetings of the International Database and Engineering Application Symposium from 1997 through 2021. These meetings were organized in various locations on three continents. Most of the papers published during these years are in the digital libraries of IEEE(1997-2007) or ACM(2008-2021)

    Establishment of a suitable dynamic formula for the construction control of driven piles and its calibration for Load and Resistance Factor Design

    Get PDF
    Dynamic pile driving formulas have been available for the field prediction of the static bearing capacity of pile foundations for well over 180 years. On account of the immense number of different formulas that have been amassed during this time frame, a review of published literature was performed to identify the most common dynamic pile driving formulas utilized in the United States and their documented reliability. The results of this review indicated that no one dynamic pile driving formula is consistently better than all the rest; however, the Hiley, Janbu, Pacific Coast Uniform Building Code (PCUBC), and Gates formulas were shown to provide, on average, the best predictions of ultimate pile capacity. In contrast, the Engineering News Record (ENR) formula, which has been probably the most widely used dynamic formula within the United States, was shown to be among the worst predictors of pile capacity. For well over 100 years, the Working Stress Design (WSD) approach has been the traditional basis for geotechnical design with regard to settlements or failure conditions. However, considerable effort has been put forth over the past couple of decades in relation to the adoption of the Load and Resistance Factor Design (LRFD) approach into geotechnical design. With the goal of producing engineered designs with consistent levels of reliability, the Federal Highway Administration (FHWA) issued a policy memorandum on June 28, 2000, requiring all new bridges initiated after October 1, 2007, to be designed according to the LRFD approach. Likewise, regionally calibrated LRFD resistance factors have been permitted by the American Association of State Highway Officials (AASHTO) to improve the economy of bridge foundation elements. Thus, the bulk of this study focused on the development of regionally calibrated LRFD resistance factors for the construction control of driven pile foundations via a suitable dynamic pile driving formula. Using data from pile load tests performed in the State of Iowa, which was analyzed for reliability and placed in a newly designed relational database management system termed PILOT-IA, the efficiency of seven dynamic pile driving formulas (i.e., the Gates, FHWA Gates, ENR, Iowa Department of Transportation (DOT) Modified ENR, Janbu, PCUBC, and Washington DOT (WSDOT) formulas) was investigated. In addition to verifying the poor performance of the ENR formula, it was demonstrated that the efficiency of the Iowa DOT Modified ENR formula, which is presently specified in the Iowa DOT\u27s Standard Specifications for Highway and Bridge Construction manual, is sufficient to allow for its recommended use with steel H-shaped and timber pile foundations driven in any soil type; these two driven pile foundation types were found to be the most commonly used in Iowa via the results of both a state- and county-level survey. More specifically, LRFD resistance factors were calibrated and verified on a pile and soil type basis for the Iowa DOT Modified ENR formula using the first-order, second-moment (FOSM) reliability approach and the findings obtained from nine full-scale field load tests performed throughout the State of Iowa on steel H-shaped piles. For a target probability of failure of 1%, LRFD resistance factors of 0.49, 0.62, and 0.50 have been recommended for use with steel H-shaped piles driven in sand, clay, and mixed soil profiles, respectively, with a factor of 0.35 having been cautiously recommended for use with timber piles driven in any soil type. Finally, a displacement-based signal matching technique was recommended for use with PDA measured data to arrive at prediction correlations for soil quake values, Smith damping factors, and the degree-of-degradation of such parameters with respect to pile penetration depth. Although an insufficient amount of data was analyzed to even begin to develop such correlations, the accuracy, uniqueness, and theoretical basis of the displacement-based signal matching approach over the more commonly employed Case Pile Wave Analysis Program (CAPWAP) approach was demonstrated. Provided the future establishment of such prediction correlations from the increased use of this proposed technique, it was suggested that a one-dimensional pile-soil model could be used in conjunction with a dynamic pile driving formula to design driven pile foundations

    Rethinking Consistency Management in Real-time Collaborative Editing Systems

    Get PDF
    Networked computer systems offer much to support collaborative editing of shared documents among users. Increasing concurrent access to shared documents by allowing multiple users to contribute to and/or track changes to these shared documents is the goal of real-time collaborative editing systems (RTCES); yet concurrent access is either limited in existing systems that employ exclusive locking or concurrency control algorithms such as operational transformation (OT) may be employed to enable concurrent access. Unfortunately, such OT based schemes are costly with respect to communication and computation. Further, existing systems are often specialized in their functionality and require users to adopt new, unfamiliar software to enable collaboration. This research discusses our work in improving consistency management in RTCES. We have developed a set of deadlock-free multi-granular dynamic locking algorithms and data structures that maximize concurrent access to shared documents while minimizing communication cost. These algorithms provide a high level of service for concurrent access to the shared document and integrate merge-based or OT-based consistency maintenance policies locally among a subset of the users within a subsection of the document – thus reducing the communication costs in maintaining consistency. Additionally, we have developed client-server and P2P implementations of our hierarchical document management algorithms. Simulations results indicate that our approach achieves significant communication and computation cost savings. We have also developed a hierarchical reduction algorithm that can minimize the space required of RTCES, and this algorithm may be pipelined through our document tree. Further, we have developed an architecture that allows for a heterogeneous set of client editing software to connect with a heterogeneous set of server document repositories via Web services. This architecture supports our algorithms and does not require client or server technologies to be modified – thus it is able to accommodate existing, favored editing and repository tools. Finally, we have developed a prototype benchmark system of our architecture that is responsive to users’ actions and minimizes communication costs

    Web-based user interface for a simple distributed security infrastructure (SDSI)

    Get PDF
    Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (p. 69).by Gillian D. Elcock.M.Eng

    Extracting information from informal communication

    Get PDF
    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references (leaves 89-93).This thesis focuses on the problem of extracting information from informal communication. Textual informal communication, such as e-mail, bulletin boards and blogs, has become a vast information resource. However, such information is poorly organized and difficult for a computer to understand due to lack of editing and structure. Thus, techniques which work well for formal text, such as newspaper articles, may be considered insufficient on informal text. One focus of ours is to attempt to advance the state-of-the-art for sub-problems of the information extraction task. We make contributions to the problems of named entity extraction, co-reference resolution and context tracking. We channel our efforts toward methods which are particularly applicable to informal communication. We also consider a type of information which is somewhat unique to informal communication: preferences and opinions. Individuals often expression their opinions on products and services in such communication. Others' may read these "reviews" to try to predict their own experiences. However, humans do a poor job of aggregating and generalizing large sets of data. We develop techniques that can perform the job of predicting unobserved opinions.(cont.) We address both the single-user case where information about the items is known, and the multi-user case where we can generalize opinions without external information. Experiments on large-scale rating data sets validate our approach.by Jason D.M. Rennie.Ph.D
    • …
    corecore