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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Mobility and context-awareness in workflow systems

Nguyen, Man Hoang, Nødtvedt, Jon Ole January 2004 (has links)
<p>This project aims to describe how workflow systems can integrate and make use of context information from context rich environments, to enhance the execution of workflow processes. Context information can for example be used to control transitions between activities, activity enactment and process/activity coordination. A dynamic contextual environment also requires that a workflow system is capable of responding to contextual events. A set of requirements for a context-aware workflow system, based on existing workflow standards, theory behind context-aware computing and activity theory, will be presented and elaborated. Prototypes, which illustrate how these requirements can be implemented in a standard based workflow system, are also provided. Based on the solutions presented in the prototypes, a new interface for a workflow enactment service is presented. This new interface serves as the link between the contextual environment and the workflow system. We also present a solution for handling context related exception states. The definition of basic terms in workflow systems are expanded to better support context-aware behaviour. Ideas and solutions for more complex requirements not met in our prototypes are also discussed, such as situated activity coordination.</p>
2

Mobility and context-awareness in workflow systems

Nguyen, Man Hoang, Nødtvedt, Jon Ole January 2004 (has links)
This project aims to describe how workflow systems can integrate and make use of context information from context rich environments, to enhance the execution of workflow processes. Context information can for example be used to control transitions between activities, activity enactment and process/activity coordination. A dynamic contextual environment also requires that a workflow system is capable of responding to contextual events. A set of requirements for a context-aware workflow system, based on existing workflow standards, theory behind context-aware computing and activity theory, will be presented and elaborated. Prototypes, which illustrate how these requirements can be implemented in a standard based workflow system, are also provided. Based on the solutions presented in the prototypes, a new interface for a workflow enactment service is presented. This new interface serves as the link between the contextual environment and the workflow system. We also present a solution for handling context related exception states. The definition of basic terms in workflow systems are expanded to better support context-aware behaviour. Ideas and solutions for more complex requirements not met in our prototypes are also discussed, such as situated activity coordination.
3

Product Context Analysis with Twitter Data

Sun, Tao January 2016 (has links)
Context. For the product manager, the product context analysis, which aims to align their products to the market needs, is very important. By understanding the market needs, the product manager knows the product context information about the environment the products conceived and the business the products take place. The product context analysis using the product context information helps the product manager find the accurate position of his/her products and support the decision-making of the products. The product context information generally could be found in the user feedbacks. And the traditional techniques of acquiring the user feedbacks can be replaced by collecting the existed online user feedbacks with a cheaper cost. Therefore, researchers did studies on the online user feedbacks and the results showed those user feedbacks contain the product context information. Therefore, in this study, I tried to elicit the product context information from the user feedbacks posted on Twitter. Objectives. Objectives of this study are 1. I investigated what kinds of Apps can be used to collect   more related Tweets, and 2. I investigated what kinds of product context information can be elicited from the collected Tweets. Methods. To achieve the first objective, I designed unified criteria for selecting Apps and collecting App-related Tweets, and then conduct the statistical analysis to find out what is/are the factor(s) affect (s) the Tweets collection. To achieve the second objective, I conducted the directed content analysis on the collected Tweets with an indicator for identifying the product context information, and then make a descriptive statistical analysis of the elicited product context information. Results. I found the top-ranked Apps or Apps in few themes like “Health and Fitness” and “Games” have more and fresher App-related Tweets. And from my collected Tweets, I can elicit at least 15 types of product context information, the types include “user experience”, “use case”, “partner”, “competitor”, “platforms” and so on. Conclusions. This is an exploratory study of eliciting product context information from the Tweets. It presented the method of collecting the App-related Tweets and eliciting product context information from the collected Tweets. It showed what kinds of App are suitable to do so and what types of product context information can be elicited from the Tweets. This study let us be aware of that the Tweets can be used for the product context analysis, and let us know the appropriate condition to use the Tweets for the product context analysis.
4

The use of immersive technologies to modulate the contextual congruency of visual, auditory and olfactory information streams important in shaping hedonic responses

Liu, Rebecca 09 August 2016 (has links)
No description available.
5

Adaptive Context Aware Services

Rondé-Oustau, Xavier January 2006 (has links)
Context information is information that describes the user's context. The goal of the Adaptive Context Aware Services (ACAS) project is to enable applications to use context information in order to adapt their behaviour to the user and his environment without requiring the user to manually change/manage parameters. While the concept of linking context aware entities together to form a logical "context network" was introduced earlier in the project, some questions regarding context information discovery and the discovery of context aware entities were previously unanswered. The goal of this thesis was to design and evaluate such a context network allowing entities todiscover each other and exchange information regarding their services and context information. For this purpose, a "Context Entity Registrar" has been developed allowing entities to register, thus they can easily be found by other entities who can query this registrar. During the design of this proposed solution, a special focus has been given to the performance of the registrar, especially how it scales when answering a large number of requests, in order to validate the design's potential as a solution to context aware entity discovery. Measurements have shown that this proposed solution scales well, making it a key element of a context network. Discovery of other entities and of context information play an important role to determine the performances of a context aware implementation. This masters thesis addresses first the issue of the architecture of the context network and then some tests to measure the performances of the proposed solution. / Context information är information som beskriver användarens omgivning. Adaptive Context Aware Services (ACAS) projektet har som mål att möjliggöra applikationer att använda kontext information för att anpassa sitt beteende till användaren och dess miljö, utan att kräva att användaren ska sätta eller hantera alla parametrar manuellt. ACAS projektet har tidigare infört konceptet "context network" som förbinder context aware enheter. Det finns dock kvar några obesvarade frågor angående upptäckt av context information och av context aware enheter.Trots att sättet att länka ihop kontextmedvetna enheter för att forma ett logiskt 'kontext nätverk' introducerades tidigare i projektet, finns det kvar några obesvarade frågor angående upptäckt av kontext information och upptäckt av kontextmedvetna enheter. Examensarbetets mål är att utforma och utvärdera ett sådant kontextnätverk som ger enheterna möjlighet att upptäcka varandra och utbyta information om tjänster och context information. Därför utvecklades "Context Entity Registrar" så att enheterna kan registrera sig för att kunna bli upptäckta av andra enheter som kan göra förfrågningar till detta register. Under designen av denna föreslagna lösning har särskild fokus lagts på registrens prestanda, speciellt avseende skalbarhet med avseende på antalet förfrågningar for att validera designens potential som lösning för kontextmedveten upptäckt av enheter. Mätningar har visat att lösningen skalar bra vilket gör kontext registret till ett nyckelelement i ett kontextnätverk. Upptäkten av andra enheter och av kontextinformation har en viktig roll i att bestämma en kontextmedveten implementations prestanda. Detta examensarbete kommer först att behandla kontextnätverkets arkitektur och därefter några testerna för att mäta prestanda i den föreslagna lösningen.
6

Distribution of Context Information using the Session Initiation Protocol (SIP)

Angeles Piña, Carlos January 2008 (has links)
Context-aware applications are applications that exploit knowledge of the situation of the user (i.e. the user’s context) to adapt their behavior, thus helping the user achieve his or her daily tasks. Today, the transfer of context information needs to take place over unreliable and dynamically changing networks. Moreover context information may be produced in different devices connected to different networks. These difficulties have limited the development of context-aware applications. This thesis presents a context distribution method exploiting the event notification mechanisms of the Session Initiation Protocol (SIP), aiming to provide access to context information regardless of where it is produced. The context distribution component presented in this thesis uses SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE) to enable context sharing by using a SIP presence server, specifically the SIP Express Router (SER) and its presence module. This context distribution component allows distribution of context information in both synchronous and asynchronous mode. The distribution mode depends on the application requirements for context distribution, as well as the nature and characteristics of the contextinformation. In this thesis, based on system scalability, the user’s mobility, and latency - recommendations are given about in which situations each mode is more suitable for distributing context information. The system was evaluated using a load generator. The evaluation revealed that the server is highly scalable. The response time for synchronous retrieval of context information is nearly constant, while in asynchronous mode the time to process a subscription increases with the amount of information in the database regarding previous subscriptions. Notifications are sent at a regular rate (≈2800 notifications per second); however there is a purposely random delay (0 to 1 second), between an update of context information (i.e. receipt of a publish message) and the start of notifications to subscribed users. The requirements of the context-aware applications using the distribution component, such as response time, have to be taken into account when deciding upon the mode of context distribution for each application. This thesis provides some empirical data to help an application developer make this selection. / Kontext-medvetna (eng. Context-aware) applikationer är applikationer som utnyttjar information om användarens situation (d.v.s. användarens kontext) och förändrar applikationens beteende i syfte att hjälpa användaren i dennes vardagliga arbetsuppgiften. Idag överförs kontextuell-information (eng. context information) i nätverk som är opålitliga och dynamiskt föränderliga. Därtill tillkommer komplexiteten att kontextuell-information är ibland producerad i olika noder anslutna till olika nätverk.Utvecklingen av kontext-medvetna applikationer har hittills begränsats av ovannämnda svårigheter. Denna avhandling presenterar en metod för att distribuera kontextuell-information genom användning av mekanismer för händelsemeddelande (eng. event notification mechanisms) inbyggda i Session Initiation Protocol (SIP). Målet är att undersöka hur metoden kan användas för att möjliggöra tillgång till kontextuell-information oavsett vart den är producerad. Komponenten för distribution av kontextuell data, som presenteras i denna uppsats, använder SIP för direktmeddelanden (eng. Instant Messaging) och tekniken “Presence Leveraging Extensions (SIMPLE)” för datadelning av kontextuell data (eng. Context sharing). För detta ändamål används SIP närvaroserver (eng. SIP presence server), mer specifikt modulen för närvaroinformation tillhörande SIP Expressroutrar (SER). Komponenten för distribution av kontextuell information möjliggör både synkront och asynkront distribution. Valet mellan de två beror delvist på applikationens kravspecifikation för distribution av kontextuell information, delvist på typen av den kontextuella informationen. Baserat på systemet skalbarhet (eng. Scalability), användarens rörlighet och latens (eng. latency) kan man ge rekommendationer vilken av de två distributionssätten, synkront eller asynkront, som är lämpligast för distributionen av kontextuell information. Systemet utvärderades med hjälp av ett program som genererar belastning (eng. load generator). Resultaten visar att systemet är mycket skalbart. Responstiden för synkront åtkomst av kontextuell information är nästan konstant, medan responstiden för asynkront åtkomst ökar med informationsmängden i databasen, i respekt till den föregående prenumerationen av kontextändringar. Händelsemeddelande skickas regelbundet ( 2800 meddelande per sekund). Vi har dock medvetet valt att skapa en slumpmässigt dröjsmål (0 till 1 sekund) mellan varje uppdatering av kontextuell information (t.ex. en kvitto på en Publish-meddelande) och den tidpunkten då händelsemeddelande skickas till de användare som prenumererar på ändringarna. För utvecklingen av varje kontext-medveten applikation, som distribuerar kontextuell information måste man ta hänsyn till responstid vid beslut huruvida man ska välja synkront eller asynkront sätt för distribution. Denna uppsats ger empirisk data som hjälper applikationsutvecklare i detta val.
7

Self-Organizing Logical-Clustering Topology for Managing Distributed Context Information

Rahman, Hasibur January 2015 (has links)
Internet of Things (IoT) is on the verge of experiencing a paradigm shift, the focus of which is the integration of people, services, context information, and things in the Connected Society, thus enabling Internet of Everything (IoE). Hundreds of billions of things will be connected to IoT/IoE by 2020. This massive immersion of things paves the way for sensing and analysing anything, anytime and anywhere. This everywhere computing coupled with Internet or web-enabled services have allowed access to a vast amount of distributed context information from heterogeneous sources. This enormous amount of context information will remain under-utilized if not properly managed. Therefore, this thesis proposes a new approach of logical-clustering as opposed to physical clustering aimed at enabling efficient context information management. However, applying this new approach requires many research challenges to be met. By adhering to a design science research method, this thesis addresses these challenges and proposes solutions to them. The thesis first outlines the architecture for realizing logical-clustering topology for which a two-tier hierarchical-distributed hash table (DHT) based system architecture and a Software Defined Networking (SDN)-like approach are utilized whereby the clustering identifications are managed on the top-level overlay (as context storage) and heterogeneous context information sources are controlled via the bottom level. The feasibility of the architecture has been proven with an ns-3 simulation tool. The next challenge is to enable scalable clustering identification dissemination, for which a distributed Publish/Subscribe (PubSub) model is developed. The massive number of immersed nodes further necessitates a dynamic self-organized system. The thesis concludes by proposing new algorithms with regard to autonomic management of IoT to bring about the self-organization. These algorithms enable to structure the logical-clustering topology in an organized way with minimal intervention from outside sources and further ensure that it evolves correctly. A distributed IoT context information-sharing platform, MediaSense, is employed and extended to prove the feasibility of the dynamic PubSub model and the correctness of self-organized algorithms and to utilize them as context storage. Promising results have provided a high number of PubSub messages per second and fast subscription matching. Self-organization further enabled logical-clustering to evolve correctly and provided results on a par with the existing MediaSense for entity joining and high discovery rates for non-concurrent entity joining. The increase in context information requires its proper management. Being able to cluster (i.e. filter) heterogeneous context information based on context similarity can help to avoid under-utilization of resources. This thesis presents an accumulation of work which can be comprehended as a step towards realizing the vision of logical-clustering topology.
8

The retrieval and reuse of engineering knowledge from records of design rationale

Wang, Hongwei January 2012 (has links)
No description available.
9

Ripples Across The Internet of Things : Context Metrics as Vehicles forRelational Self-Organization

Walters, Jamie January 2011 (has links)
The current paradigm shift in computing has placed mobile computation at the centre of focus. Users are now even more connected; demanding everything everywhere services. These services, such as social networking and media, benefit from the availability of context information seamlessly gathered and shared; providing customized and user-centric experiences. The distribution of context information no longer conforms to the paradigms of the existing Internet with regards to heterogeneity, connectivity and availability. This mandates new approaches towards its organization and provisioning in support of dependent applications and services. In response to these developments, the work summarized in this thesis addresses the fundamental problem of presenting context information in organized models as relevant subsets of global information. In approaching this problem, I introduced a distributed collection of context objects that can be arranged into simple relevant subsets called context schemata and presented to applications and services in supporting the realization of context based user experiences. Acknowledging the dynamic behaviour inherent of the real world interactions, I introduced an algorithm for measuring the proximities and similarities among these context objects, providing a metric through which to achieve organization. Additionally, I provided a means of ranking heterogeneous and distributed sensors in response to real time interaction between users and their digital ecosystem. Ranking provides an additional metric with which to achieve organization or identifying important and reputable information sources. The work I present here, additionally details my approach to realizing this complete behaviour an a distributed overlay, exploiting its properties for distribution, persistence and messaging. The overlay is also utilized for the provisioning of the supporting context information. Improvements in the ability to discover and attach new context information sources is fundamental to the ability to continually maintain expressions of context, derived from heterogeneous and disparate sources. By being able to create relevant subsets of organized data related to the requirements of applications and services in an end-point, infrastructures are realized for connecting and supporting the increasingly large numbers of users and their sources of information. Coupled with the distribution, these infrastructures realize improvements with regards to the effort required to achieve the same results. The culmination of the work presented in this thesis is an effort to enable seamless context-centric solutions on a future Internet of Things and thus constituting an adequate solution to the challenges raised above.
10

Distributed Intelligence-Assisted Autonomic Context-Information Management : A context-based approach to handling vast amounts of heterogeneous IoT data

Rahman, Hasibur January 2018 (has links)
As an implication of rapid growth in Internet-of-Things (IoT) data, current focus has shifted towards utilizing and analysing the data in order to make sense of the data. The aim of which is to make instantaneous, automated, and informed decisions that will drive the future IoT. This corresponds to extracting and applying knowledge from IoT data which brings both a substantial challenge and high value. Context plays an important role in reaping value from data, and is capable of countering the IoT data challenges. The management of heterogeneous contextualized data is infeasible and insufficient with the existing solutions which mandates new solutions. Research until now has mostly concentrated on providing cloud-based IoT solutions; among other issues, this promotes real-time and faster decision-making issues. In view of this, this dissertation undertakes a study of a context-based approach entitled Distributed intelligence-assisted Autonomic Context Information Management (DACIM), the purpose of which is to efficiently (i) utilize and (ii) analyse IoT data. To address the challenges and solutions with respect to enabling DACIM, the dissertation starts with proposing a logical-clustering approach for proper IoT data utilization. The environment that the number of Things immerse changes rapidly and becomes dynamic. To this end, self-organization has been supported by proposing self-* algorithms that resulted in 10 organized Things per second and high accuracy rate for Things joining. IoT contextualized data further requires scalable dissemination which has been addressed by a Publish/Subscribe model, and it has been shown that high publication rate and faster subscription matching are realisable. The dissertation ends with the proposal of a new approach which assists distribution of intelligence with regard to analysing context information to alleviate intelligence of things. The approach allows to bring few of the application of knowledge from the cloud to the edge; where edge based solution has been facilitated with intelligence that enables faster responses and reduced dependency on the rules by leveraging artificial intelligence techniques. To infer knowledge for different IoT applications closer to the Things, a multi-modal reasoner has been proposed which demonstrates faster response. The evaluations of the designed and developed DACIM gives promising results, which are distributed over seven publications; from this, it can be concluded that it is feasible to realize a distributed intelligence-assisted context-based approach that contribute towards autonomic context information management in the ever-expanding IoT realm. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 7: Submitted.</p>

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