533 research outputs found
Secure object-oriented databases
D.Phil. (Computer Science)The need for security in a database is obvious. Object-orientation enables databases to be used in applications where other database models are not adequate. It is thus clear that security of object-oriented databases must be investigated..
Proposing a New System Architecture for Next Generation Learning Environment
Indiana University-Purdue University Indianapolis (IUPUI)The emergence of information exchange and act of offering features through external interfaces is a vast but immensely valuable challenge, and essential elements of learning environments cannot be excluded. Nowadays, there are a lot of different service providers working in the learning systems market and each of them has their own advantages. On that premise, in today's world even large learning management systems are trying to cooperate with each other in order to be best. For instance, Instructure is a substantial company and can easily employ a dedicated team tasked with the development of a video conferencing functionality, but it chooses to use an open source alternative instead: The BigBlueButton. Unfortunately, different learning system manufacturers are using different technologies for various reasons, making integration that much harder.
Standards in learning environments have come to resolve problems regarding exchanging information, providing and consuming functionalities externally and simultaneously minimizing the amount of effort needed to integrate systems. In addition to defining and simplifying these standards, careful consideration is essential when designing new, comprehensive and useful systems, as well as adding interoperability to existing systems, all which subsequently took part in this research.
In this research I have reviewed most of the standards and protocols for integration in learning environments and proposed a revised approach for app stores in learning environments. Finally, as a case study, a learning tool has been developed to avail essential functionalities of a social educational learning management system integrated with other learning management systems. This tool supports the dominant and most popular standards for interoperability and can be added to learning management systems within seconds
Investigations of collaborative design environments: A framework for real-time collaborative 3D CAD
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This research investigates computer-based collaborative design environments, in particular issues of real-time collaborative 3D CAD. The thesis first presents a broad perspective of collaborative design environments with a preliminary case study of team design activities in a conventional and a computer mediated setting. This study identifies the impact and the feasibility of computer support for collaborative design and suggests four kinds of essential technologies for a successful collaborative design environment: information-sharing systems, synchronous and asynchronous co- working tools, project management systems, and communication systems. A new conceptual framework for a real-time collaborative 3D design tool, Shared Stage, is proposed based upon the preliminary study. The Shared Stage is defined as a shared 3D design workspace aiming to smoothly incorporate shared 3D workspaces into existing individual 3D workspaces. The addition of a Shared Stage allows collaborating designers to interact in real-time and to have a dynamic and interactive exchange of intermediate 3D design data. The acceptability of collaborative features is maximised by maintaining consistency of the user interface between 3D CAD systems. The framework is subsequently implemented as a software prototype using a new software development environment, customised by integrating related real-time and 3D graphic software development tools. Two main components of the Shared Stage module in the prototype, the Synchronised Stage View (SSV) and the Data Structure Diagram (DSD), provide essential collaborative features for real-time collaborative 3D CAD. These features include synchronised shared 3D representation, dynamic data exchange and awareness support in 3D workspaces. The software prototype is subsequently evaluated to examine the usefulness and usability. A range of quantitative and qualitative methods is used to evaluate the impact of the Shared Stage. The results, including the analysis of collaborative interactions and user perception, illustrate that the Shared Stage is a feasible and valuable addition for real-time collaborative 3D CAD. This research identifies the issues to be addressed for collaborative design environments and also provides a new framework and development strategy of a novel real-time collaborative 3D CAD system. The framework is successfully demonstrated through prototype implementation and an analytical usability evaluation.Financial support from the Department and from the UK government through the Overseas Research Studentship Awards
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Mobile collaborative working environment of product design
In response to the arrival of new Web/Internet environments, one of the most attractive challenges in current research is to exploit wireless computing technologies in collaborative product design, and hence to build a ubiquitous mobile information system to enable the collaborative product design within a mobile environment. However, the literature review reveals that although the progress of mobile technologies on wireless networks has largely changed the way people access the Internet; little has been achieved in mobile computing for collaborative product design. The reason is that, due to the distinct features of mobile devices and wireless networks (such as small display screen, limited bandwidth, unreliability of wireless networks, etc.), the methodologies and technologies used in stationary networks are not always applicable to mobile systems. The aim of this research is to establish a Wireless Internet-based Collaborative Working Environment for product design through the combination of multiple technologies, by including: Web services, Parametric Design, the Semantic Web, Agent and Flex Technologies. In order to create, deploy, and manage the distributed resources, Web service is used to implement design resource integration in a platform-independent manner. In addition, Semantic Web Technology is used to create a general knowledge base. This approach includes two components: (1) ontology is used to represent abstract views of product data and (2) added semantic rules are also used to represent relationships among product data. Therefore, an ontology-based description model is thus proposed to facilitate expression and organisation of product information in order to manage and deploy the distributed design resources
NSSDC Conference on Mass Storage Systems and Technologies for Space and Earth Science Applications, volume 2
This report contains copies of nearly all of the technical papers and viewgraphs presented at the NSSDC Conference on Mass Storage Systems and Technologies for Space and Earth Science Application. This conference served as a broad forum for the discussion of a number of important issues in the field of mass storage systems. Topics include the following: magnetic disk and tape technologies; optical disk and tape; software storage and file management systems; and experiences with the use of a large, distributed storage system. The technical presentations describe, among other things, integrated mass storage systems that are expected to be available commercially. Also included is a series of presentations from Federal Government organizations and research institutions covering their mass storage requirements for the 1990's
Access control in semantic information systems
Access control has evolved in file systems. Early access control was limited and didn't handle identities. Access control then shifted to develop concepts such as identities. The next progression was the ability to take these identities and use lists to control what those identities can do. At this point we start to see more areas implementing access control such as web information systems. Web information systems has themselves started to raise the profile of semantic information. As semantic information systems start to expand new opportunities in access control become available to be explored.
This dissertation introduces an experimental file system. The file system explores the concept of utilising metadata in a file system. The metadata is supported through the use of a database system. The introduction of the database enables the use of features such as views within the file system. Databases also provide a rich query language to utilise when nding information. The database aides the development of semantic meaning for the metadata stored. This provides greater meaning to the metadata and enables a platform for rethinking access contro
Mobiilse värkvõrgu protsessihaldus
Värkvõrk, ehk Asjade Internet (Internet of Things, lüh IoT) edendab lahendusi nagu nn tark linn, kus meid igapäevaselt ümbritsevad objektid on ühendatud infosüsteemidega ja ka üksteisega. Selliseks näiteks võib olla teekatete seisukorra monitoorimissüsteem. Võrku ühendatud sõidukitelt (nt bussidelt) kogutakse videomaterjali, mida seejärel töödeldakse, et tuvastada löökauke või lume kogunemist. Tavaliselt hõlmab selline lahendus keeruka tsentraalse süsteemi ehitamist. Otsuste langetamiseks (nt milliseid sõidukeid parasjagu protsessi kaasata) vajab keskne süsteem pidevat ühendust kõigi IoT seadmetega. Seadmete hulga kasvades võib keskne lahendus aga muutuda pudelikaelaks.
Selliste protsesside disaini, haldust, automatiseerimist ja seiret hõlbustavad märkimisväärselt äriprotsesside halduse (Business Process Management, lüh BPM) valdkonna standardid ja tööriistad. Paraku ei ole BPM tehnoloogiad koheselt kasutatavad uute paradigmadega nagu Udu- ja Servaarvutus, mis tuleviku värkvõrgu jaoks vajalikud on. Nende puhul liigub suur osa otsustustest ja arvutustest üksikutest andmekeskustest servavõrgu seadmetele, mis asuvad lõppkasutajatele ja IoT seadmetele lähemal. Videotöötlust võiks teostada mini-andmekeskustes, mis on paigaldatud üle linna, näiteks bussipeatustesse.
Arvestades IoT seadmete üha suurenevat hulka, vähendab selline koormuse jaotamine vähendab riski, et tsentraalne andmekeskust ülekoormamist.
Doktoritöö uurib, kuidas mobiilsusega seonduvaid IoT protsesse taoliselt ümber korraldada, kohanedes pidevalt muutlikule, liikuvate seadmetega täidetud servavõrgule. Nimelt on ühendused katkendlikud, mistõttu otsuste langetus ja planeerimine peavad arvestama muuhulgas mobiilseadmete liikumistrajektoore. Töö raames valminud prototüüpe testiti Android seadmetel ja simulatsioonides. Lisaks valmis tööriistakomplekt STEP-ONE, mis võimaldab teadlastel hõlpsalt simuleerida ja analüüsida taolisi probleeme erinevais realistlikes stsenaariumites nagu seda on tark linn.The Internet of Things (IoT) promotes solutions such as a smart city, where everyday objects connect with info systems and each other. One example is a road condition monitoring system, where connected vehicles, such as buses, capture video, which is then processed to detect potholes and snow build-up. Building such a solution typically involves establishing a complex centralised system. The centralised approach may become a bottleneck as the number of IoT devices keeps growing. It relies on constant connectivity to all involved devices to make decisions, such as which vehicles to involve in the process.
Designing, automating, managing, and monitoring such processes can greatly be supported using the standards and software systems provided by the field of Business Process Management (BPM). However, BPM techniques are not directly applicable to new computing paradigms, such as Fog Computing and Edge Computing, on which the future of IoT relies. Here, a lot of decision-making and processing is moved from central data-centers to devices in the network edge, near the end-users and IoT sensors.
For example, video could be processed in mini-datacenters deployed throughout the city, e.g., at bus stops. This load distribution reduces the risk of the ever-growing number of IoT devices overloading the data center.
This thesis studies how to reorganise the process execution in this decentralised fashion, where processes must dynamically adapt to the volatile edge environment filled with moving devices. Namely, connectivity is intermittent, so decision-making and planning need to involve factors such as the movement trajectories of mobile devices.
We examined this issue in simulations and with a prototype for Android smartphones. We also showcase the STEP-ONE toolset, allowing researchers to conveniently simulate and analyse these issues in different realistic scenarios, such as those in a smart city.
https://www.ester.ee/record=b552551
Training deep retrieval models with noisy datasets
In this thesis we study loss functions that allow to train Convolutional Neural
Networks (CNNs) under noisy datasets for the particular task of Content-
Based Image Retrieval (CBIR). In particular, we propose two novel losses to fit
models that generate global image representations. First, a Soft-Matching (SM)
loss, exploiting both image content and meta data, is used to specialized general
CNNs to particular cities or regions using weakly annotated datasets. Second,
a Bag Exponential (BE) loss inspired by the Multiple Instance Learning (MIL)
framework is employed to train CNNs for CBIR under noisy datasets.
The first part of the thesis introduces a novel training framework that, relying
on image content and meta data, learns location-adapted deep models that
provide fine-tuned image descriptors for specific visual contents. Our networks,
which start from a baseline model originally learned for a different task, are specialized
using a custom pairwise loss function, our proposed SM loss, that uses
weak labels based on image content and meta data.
The experimental results show that the proposed location-adapted CNNs
achieve an improvement of up to a 55% over the baseline networks on a landmark
discovery task. This implies that the models successfully learn the visual
clues and peculiarities of the region for which they are trained, and generate
image descriptors that are better location-adapted. In addition, for those landmarks
that are not present on the training set or even other cities, our proposed
models perform at least as well as the baseline network, which indicates a good
resilience against overfitting.
The second part of the thesis introduces the BE Loss function to train CNNs
for image retrieval borrowing inspiration from the MIL framework. The loss
combines the use of an exponential function acting as a soft margin, and a MILbased
mechanism working with bags of positive and negative pairs of images.
The method allows to train deep retrieval networks under noisy datasets, by
weighing the influence of the different samples at loss level, which increases the
performance of the generated global descriptors. The rationale behind the improvement
is that we are handling noise in an end-to-end manner and, therefore,
avoiding its negative influence as well as the unintentional biases due to fixed
pre-processing cleaning procedures. In addition, our method is general enough
to suit other scenarios requiring different weights for the training instances (e.g.
boosting the influence of hard positives during training). The proposed bag exponential
function can bee seen as a back door to guide the learning process
according to a certain objective in a end-to-end manner, allowing the model to
approach such an objective smoothly and progressively.
Our results show that our loss allows CNN-based retrieval systems to be
trained with noisy training sets and achieve state-of-the-art performance. Furthermore,
we have found that it is better to use training sets that are highly
correlated with the final task, even if they are noisy, than training with a clean set that is only weakly related with the topic at hand. From our point of view,
this result represents a big leap in the applicability of retrieval systems and help
to reduce the effort needed to set-up new CBIR applications: e.g. by allowing
a fast automatic generation of noisy training datasets and then using our bag
exponential loss to deal with noise. Moreover, we also consider that this result
opens a new line of research for CNN-based image retrieval: let the models decide
not only on the best features to solve the task but also on the most relevant
samples to do it.Programa de Doctorado en Multimedia y Comunicaciones por la Universidad Carlos III de Madrid y la Universidad Rey Juan CarlosPresidente: Luis Salgado Álvarez de Sotomayor.- Secretario: Pablos Martínez Olmos.- Vocal: Ernest Valveny Llobe
Multimedia
The nowadays ubiquitous and effortless digital data capture and processing capabilities offered by the majority of devices, lead to an unprecedented penetration of multimedia content in our everyday life. To make the most of this phenomenon, the rapidly increasing volume and usage of digitised content requires constant re-evaluation and adaptation of multimedia methodologies, in order to meet the relentless change of requirements from both the user and system perspectives. Advances in Multimedia provides readers with an overview of the ever-growing field of multimedia by bringing together various research studies and surveys from different subfields that point out such important aspects. Some of the main topics that this book deals with include: multimedia management in peer-to-peer structures & wireless networks, security characteristics in multimedia, semantic gap bridging for multimedia content and novel multimedia applications
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