242 research outputs found

    Study for the design of a management system for AGV networks

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    Automated Guided Vehicles are a vital part of the future intelligent manufacturing processes. In order to make the better profit, it is important to study if deadlocks can occur and how to tackle them. In this project we demonstrate how Petri Net models, which are perfect for representing deadlocks, can be mapped in the simulation software FlexSim. Eventually, we are using this software in order to evaluate different study cases with deadlocks

    Automated interpretation of digital images of hydrographic charts.

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    Details of research into the automated generation of a digital database of hydrographic charts is presented. Low level processing of digital images of hydrographic charts provides image line feature segments which serve as input to a semi-automated feature extraction system, (SAFE). This system is able to perform a great deal of the building of chart features from the image segments simply on the basis of proximity of the segments. The system solicits user interaction when ambiguities arise. IThe creation of an intelligent knowledge based system (IKBS) implemented in the form of a backward chained production rule based system, which cooperates with the SAFE system, is described. The 1KBS attempts to resolve ambiguities using domain knowledge coded in the form of production rules. The two systems communicate by the passing of goals from SAFE to the IKBS and the return of a certainty factor by the IKBS for each goal submitted. The SAFE system can make additional feature building decisions on the basis of collected sets of certainty factors, thus reducing the need for user interaction. This thesis establishes that the cooperating IKBS approach to image interpretation offers an effective route to automated image understanding

    9th International Workshop "What can FCA do for Artificial Intelligence?" (FCA4AI 2021)

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    International audienceFormal Concept Analysis (FCA) is a mathematically well-founded theory aimed at classification and knowledge discovery that can be used for many purposes in Artificial Intelligence (AI). The objective of the ninth edition of the FCA4AI workshop (see http://www.fca4ai.hse.ru/) is to investigate several issues such as: how can FCA support various AI activities (knowledge discovery, knowledge engineering, machine learning, data mining, information retrieval, recommendation...), how can FCA be extended in order to help AI researchers to solve new and complex problems in their domains, and how FCA can play a role in current trends in AI such as explainable AI and fairness of algorithms in decision making.The workshop was held in co-location with IJCAI 2021, Montréal, Canada, August, 28 2021

    Mechanoresponsive drug delivery: harnessing forces for controlled release

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    Mechanically-activated delivery systems harness existing physiological and/or externally-applied forces to provide spatiotemporal control over the release of active agents. The presence and necessity of these forces in the human body and in the increasing use of mechanically-driven medical devices (e.g., stents, balloon catheters, gastric bands, tissue expanders) can serve as functional dynamic triggers. Therefore, this dissertation investigates the use of applied tensile strain and cyclic loading to control release of entrapped agents, and further translates the concept towards clinical applications by integrating the system with commercial medical devices that provide precise forces to trigger release. As an initial proof-of-concept, mechanoresponsive composites, consisting of highly-textured superhydrophobic barrier coatings over a hydrophilic substrate, are fabricated. The release of entrapped agents, controlled by the magnitude of applied strain, results in a graded response due to water infiltration through propagating patterned cracks in the coating. The strain-dependent delivery of anticancer agents with in vitro efficacy as well as the ex vivo delivery to esophageal tissue with an integrated stent system are demonstrated. Release is further modulated by barrier coating properties. Thicker coatings afford slower release rates with preserved in vitro activity for both a chemotherapeutic and an enzyme. Localizing coating crack patterns based on different geometric stress concentration factors further controls the selective sequential release of multiple agents. Finally, the development of a reversible mechanoresponsive system is investigated to provide cycle-mediated pulsatile release. Optimization of mechanical parameters results in delivery of multiple doses. To translate this concept towards the clinic, the system is integrated with commercial balloon catheters to provide multidose delivery of small molecules to ex vivo vessels. Using the inherent inflation and deflation of the catheter to trigger release, the system enhances existing capabilities to treat cardiovascular and peripheral artery diseases. In summary, the development of mechanoresponsive systems that respond to tensile strain and cycle number are described for the delivery of a wide-range of active agents (hydrophilic and hydrophobic small molecules as well as an enzyme), and their integration with existing medical devices. Furthermore, the comprehensive range of specific kinetic profiles, including triggered release, pulsatile delivery, and the sequential delivery of multiple agents, showcases the capabilities and versatility of these dynamic mechanoresponsive systems to modulate release for the treatment of various clinical diseases.2019-02-20T00:00:00

    A framework for decentralised trust reasoning.

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    Recent developments in the pervasiveness and mobility of computer systems in open computer networks have invalidated traditional assumptions about trust in computer communications security. In a fundamentally decentralised and open network such as the Internet, the responsibility for answering the question of whether one can trust another entity on the network now lies with the individual agent, and not a priori a decision to be governed by a central authority. Online agents represent users' digital identities. Thus, we believe that it is reasonable to explore social models of trust for secure agent communication. The thesis of this work is that it is feasible to design and formalise a dynamic model of trust for secure communications based on the properties of social trust. In showing this, we divide this work into two phases. The aim of the first is to understand the properties and dynamics of social trust and its role in computer systems. To this end, a thorough review of trust, and its supporting concept, reputation, in the social sciences was carried out. We followed this by a rigorous analysis of current trust models, comparing their properties with those of social trust. We found that current models were designed in an ad-hoc basis, with regards to trust properties. The aim of the second phase is to build a framework for trust reasoning in distributed systems. Knowledge from the previous phase is used to design and formally specify, in Z, a computational trust model. A simple model for the communication of recommendations, the recommendation protocol, is also outlined to complement the model. Finally an analysis of possible threats to the model is carried out. Elements of this work have been incorporated into Sun's JXTA framework and Ericsson Research's prototype trust model

    SPKI/SDSI HTTP Server / Certificate Chain Discovery in SPKI/SDSI

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    Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (leaves 155-160).The issue of trust is of growing importance as our communities become increasingly interconnected. When resources are shared over an untrusted network, how are decisions on which principals are authorized to perform particular actions determined? SPKI/SDSI, a security infrastructure based on public-keys, is designed to facilitate the development of scalable, secure, distributed computing systems. It provides fine-grained access control, using a local name space hierarchy, and a simple, flexible, trust policy model; these features allow for the ability to create groups and delegate authorizations. Project Geronimo, named after the famous Native-American Apache chief, explores the viability of SPKI/SDSI by using it to provide access control over the Web. The infrastructure was integrated into the Netscape web client and Apache web server, using a previously developed SPKI/SDSI C Library. This thesis focuses on the server implementation. An SPKI/SDSI Apache module was designed and implemented: its principle functions are to protect web objects using SPKI/SDSI ACLs, and to determine whether HTTP client requests should be permitted to perform particular operations on protected objects. An administrative tool was developed to enable ACLs to be created, and updated, securely. The thesis also describes the algorithm for certificate chain discovery in SPKI/SDSI. Finally, the demonstration developed for Project Geronimo is outlined. The demo was successfully shown to our sponsors and various groups within the Laboratory for Computer Science.by Dwaine E. Clarke.M.Eng

    Proceedings of the 2009 Joint Workshop of Fraunhofer IOSB and Institute for Anthropomatics, Vision and Fusion Laboratory

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    The joint workshop of the Fraunhofer Institute of Optronics, System Technologies and Image Exploitation IOSB, Karlsruhe, and the Vision and Fusion Laboratory (Institute for Anthropomatics, Karlsruhe Institute of Technology (KIT)), is organized annually since 2005 with the aim to report on the latest research and development findings of the doctoral students of both institutions. This book provides a collection of 16 technical reports on the research results presented on the 2009 workshop
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