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Konduru, Prathisrihas Reddy. "Performance Analysis of Service in Heterogeneous Operational Environments." Thesis, Blekinge Tekniska Högskola, Institutionen för kommunikationssystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-13385.
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Context. In recent years there is a rapid increase in demand for cloud services, as cloud computing has become a flexible platform for hosting micro services over the Internet.~Micro services are the core elements of service oriented architecture (SOA) that facilitate the deployment of distributed software systems. Objectives. This thesis work aims at developing a typical service architecture to facilitate the deployment of compute and I/O intensive services. The thesis work also aims at evaluating the service times of these services when their respective sub services are deployed in heterogeneous environments with various loads. Methods. The thesis work has been carried out using an experimental test bed in order to evaluate the performance. The transport level performance metric called Response time is measured. It is the time taken by the server to serve the request sent by the client. Experiments have been conducted based on the objectives that are to be achieved. Results. The results obtained from the experimentation contain the average service times of a service when it is deployed on both virtual and non-virtual environments. The virtual environment is provided by Docker containers. They also include the variation in the position of their sub services. Conclusions. From results, it can be concluded that the total service times obtained are less in the case of non-virtual environment when compared to container environment.
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Čaušević, Aida. "Formal Approaches for Behavioral Modeling and Analysis of Design-time Services and Service Negotiations." Doctoral thesis, Mälardalens högskola, Inbyggda system, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-23271.
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During the past decade service-orientation has become a popular design paradigm, offering an approach in which services are the functional building blocks. Services are self-contained units of composition, built to be invoked, composed, and destroyed on (user) demand. Service-oriented systems (SOS) are a collection of services that are developed based on several design principles such as: (i) loose coupling between services (e.g., inter-service communication can involve either simple data passing or two or more connected services coordinating some activity) that allows services to be independent, yet highly interoperable when required; (ii) service abstraction, which emphasizes the need to hide as many implementation details as possible, yet still exposing functional and extra-functional capabilities that can be offered to service users; (iii) service reusability provided by the existing services in a rapid and flexible development process; (iv) service composability as one of the main assets of SOS that provide a design platform for services to be composed and decomposed, etc. One of the main concerns in such systems is ensuring service quality per se, but also guaranteeing the quality of newly composed services. To accomplish the above, we consider two system perspectives: the developer's and the user's view, respectively. In the former, one can be assumed to have access to the internal service representation: functionality, enabled actions, resource usage, and interactions with other services. In the second, one has information primarily on the service interface and exposed capabilities (attributes/features). Means of checking that services and service compositions meet the expected requirements, the so-called correctness issue, can enable optimization and possibility to guarantee a satisfactory level of a service composition quality. In order to accomplish exhaustive correctness checks of design-time SOS, we employ model-checking as the main formal verification technique, which eventually provides necessary information about quality-of-service (QoS), already at early stages of system development. ~As opposed to the traditional approach of software system construction, in SOS the same service may be offered at various prices, QoS, and other conditions, depending on the user needs. In such a setting, the interaction between involved parties requires the negotiation of what is possible at request time, aiming at meeting needs on demand. The service negotiation process often proceeds with timing, price, and resource constraints, under which users and providers exchange information on their respective goals, until reaching a consensus. Hence, a mathematically driven technique to analyze a priori various ways to achieve such goals is beneficial for understanding what and how can particular goals be achieved. This thesis presents the research that we have been carrying out over the past few years, which resulted in developing methods and tools for the specification, modeling, and formal analysis of services and service compositions in SOS. The contributions of the thesis consist of: (i)constructs for the formal description of services and service compositions using the resource-aware timed behavioral language called REMES; (ii) deductive and algorithmic approaches for checking correctness of services and service compositions;(iii) a model of service negotiation that includes different negotiation strategies, formally analyzed against timing and resource constraints; (iv) a tool-chain (REMES SOS IDE) that provides an editor and verification support (by integration with the UPPAAL model-checker) to REMES-based service-oriented designs;(v) a relevant case-study by which we exercise the applicability of our framework.The presented work has also been applied on other smaller examples presented in the published papers.Under det senaste årtiondet har ett tjänstorienterat paradigm blivit allt-mer populärt i utvecklingen av datorsystem. I detta paradigm utgör så kallade tjänster den minsta funktionella systemenheten. Dessa tjänster är konstruerade så att de kan skapas, användas, sammansättas och avslutas separat. De ska vara oberoende av varandra samtidigt som de ska kunna fungera effektivt tillsammans och i samarbete med andra system när så behövs. Vidare ska tjänsterna dölja sina interna implementa-tionsdetaljer i så stor grad som möjligt, samtidigt som deras fulla funktionalitet ska exponeras för systemdesignern. Tjänsterna ska också på ett enkelt sätt kunna återanvändas och sammansättas i en snabb och flexibel utvecklingsprocess.En av de viktigaste aspekterna i tjänsteorienterade datorsystem är att kunna säkerställa systemens kvalitet. För att åstadkomma detta ärdet viktigt att få en djupare insikt om tjänstens interna funktionalitet, i termer av möjliga operationer, resursinformation, samt tänkbar inter-aktion med andra tjänster. Detta är speciellt viktigt när utvecklaren har möjlighet att välja mellan två funktionellt likvärda tjänster somär olika med avseende på andra egenskaper, såsom responstid eller andra resurskrav. I detta sammanhang kan en matematisk beskrivning av en tjänsts beteende ge ökad förståelse av tjänstemodellen, samt hjälpa användaren att koppla ihop tjänster på ett korrekt sätt. En matematisk beskrivning öppnar också upp för ett sätt att matematiskt resonera kring tjänster. Metoder för att kontrollera att komponerade tjänstermöter ställda resurskrav möjliggör också resursoptimering av tjänster samt verifiering av ställda kvalitetskrav.I denna avhandling presenteras forskning som har bedrivits under de senaste åren. Forskningen har resulterat i metoder och verktyg föratt specificera, modellera och formellt analysera tjänster och sammansättning av tjänster. Arbetet i avhandlingen består av (i) en formell definition av tjänster och sammansättning av tjänster med hjälp avett resursmedvetet formellt specifikationsspråk kallat Remes; (ii) två metoder för att analysera tjänster och kontrollera korrektheten i sammansättning av tjänster, både deduktivt och algoritmiskt; (iii) en modell av förhandlingsprocessen vid sammansättning av tjänster som inkluderar olika förhandlingsstrategier; (iv) ett antal verktyg som stödjer dessa metoder. Metoderna har använts i ett antal fallstudier som är presenterade i de publicerade artiklarna.
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Visockas, Vilius. "Comparing Expected and Real–Time Spotify Service Topology." Thesis, KTH, Kommunikationssystem, CoS, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-96352.
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Spotify is a music streaming service that allows users to listen to their favourite music. Due to the rapid growth in the number of users, the amount of processing that must be provided by the company’s data centers is also growing. This growth in the data centers is necessary, despite the fact that much of the music content is actually sourced by other users based on a peer-to-peer model. Spotify’s backend (the infrastructure that Spotify operates to provide their music streaming service) consists of a number of different services, such as track search, storage, and others. As this infrastructure grows, some service may behave not as expected. Therefore it is important not only for Spotify’s operations (footnote: Also known as the Service Reliability Engineers Team (SRE)) team, but also for developers, to understand exactly how the various services are actually communicating. The problem is challenging because of the scale of the backend network and its rate of growth. In addition, the company aims to grow and expects to expand both the number of users and the amount of content that is available. A steadily increasing feature-set and support of additional platforms adds to the complexity. Another major challenge is to create tools which are useful to the operations team by providing information in a readily comprehensible way and hopefully integrating these tools into their daily routine. The ultimate goal is to design, develop, implement, and evaluate a tool which would help the operations team (and developers) to understand the behavior of the services that are deployed on Spotify’s backend network. The most critical information is to alert the operations staff when services are not operating as expected. Because different services are deployed on different servers the communication between these services is reflected in the network communication between these servers. In order to understand how the services are behaving when there are potentially many thousands of servers we will look for the patterns in the topology of this communication, rather than looking at the individual servers. This thesis describes the tools that successfully extract these patterns in the topology and compares them to the expected behavior.Spotify är en växande musikströmningstjänst som möjliggör för dess användare att lyssna på sin favoritmusik. Med ett snabbt växande användartal, följer en tillväxt i kapacitet som måste tillhandahållas genom deras datacenter. Denna växande kapacitet är nödvändig trots det faktum att mycket av deras innehåll hämtas från andra användare via en peer-to-peer modell. Spotifys backend (den infrastruktur som kör Spotifys tjänster) består av ett antal distinkta typer som tillhandahåller bl.a. sökning och lagring. I takt med att deras backend växer, ökar risken att tjänster missköter sig. Därför är det inte bara viktigt för Spotifys driftgrupp, utan även för deras utvecklare, att förstå hur dessa kommunicerar. Detta problem är en utmaning p.g.a. deras storskaliga infrastruktur, och blir större i takt med att den växer. Företaget strävar efter tillväxt och förväntar detta i både antalet användare och tillgängligt innehåll. Stadigt ökande funktioner och antalet distinkta plattformar bidrar till komplexitet. Ytterligare en utmaning är att bidra med verktyg som kan användas av driftgrupp för att tillhandahålla information i ett tillgängligt och överskådligt format, och att förhoppningsvis integrera dessa i en daglig arbetsrutin. Det slutgiltiga målet är att designa, utveckla, implementera och utvärdera ett verktyg som låter deras driftgrupp (och utvecklare) förstå beteenden i olika tjänster som finns i Spotifys infrastruktur. Då dessa tjänster är utplacerade på olika servrar, reflekteras kommunikationen mellan dem i deras nätverketskommunikation. För att förstå tjänsternas beteende när det potentiellt kan finnas tusentals servrar bör vi leta efter mönster i topologin, istället för beteenden på individuella servrar.
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Tang, Chen. "Forecasting Service Metrics for Network Services." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-284505.
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As the size and complexity of the internet increased dramatically in recent years,the burden of network service management also became heavier. The need foran intelligent way for data analysis and forecasting becomes urgent. The wideimplementation of machine learning and data analysis methods provides a newway to analyze large amounts of data.In this project, I study and evaluate data forecasting methods using machinelearning techniques and time series analysis methods on data collected fromthe KTH testbed. Comparing different methods with respect to accuracy andcomputing overhead I propose the best method for data forecasting for differentscenarios.The results show that machine learning techniques using regression can achievebetter performance with higher accuracy and smaller computing overhead. Timeseries data analysis methods have relatively lower accuracy, and the computingoverhead is much higher than machine learning techniques on the datasetsevaluated in this project.Eftersom storleken och komplexiteten på internet har ökat dramatiskt under de senaste åren så har belastningen av nätverkshantering också blivit tyngre. Behovet av ett intelligent sätt för dataanalys och prognos blir brådskande. Den breda implementeringen av maskininlärningsmetoder och dataanalysmetoder ger ett nytt sätt att analysera stora mängder data.I detta projekt studerar och utvärderar jag dataprognosmetoder med hjälp av maskininlärningstekniker och analyser av tidsserier som samlats in från KTHtestbädden. Baserat på jämförelse av olika metoder med avseende på noggrannhet och beräkningskostnader, så föreslår jag föreslår den bästa metoden för dataprognoser för olika scenarier.Resultaten visar att maskininlärningstekniker som använder regression kan uppnå bättre prestanda med högre noggrannhet och mindre datoromkostnader. Metoderför dataanalys av tidsserier har relativt lägre noggrannhet, och beräkningsomkostnaderna är mycket högre än maskininlärningstekniker på de datauppsättningar som utvärderatsi detta projekt.
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Lokshin, Kirill, Amit Puri, Dana Irvin, Frank Ross, and Rebecca Rush. "Implementing Real-time Provisioning for Space Link Extension (SLE) Service Instances." International Foundation for Telemetering, 2012. http://hdl.handle.net/10150/581641.
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ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, CaliforniaSpace Link Extension (SLE) is a set of recommended standards for mission cross support developed by the Consultative Committee for Space Data Systems (CCSDS). The SLE recommendations define protocols for extending the space link from ground terminals to other facilities deeper within a ground network, allowing distributed access to space link telecommand and telemetry services. The SLE protocols are widely used to provide cross support between sites, programs, and agencies. In traditional SLE deployments, individual service instances have been manually provisioned well in advance of the commencement of cross support for a particular mission, and hardware and software resources have been allocated to those service instances at the time of provisioning. While valid, this approach requires that dedicated resources be provided for each mission and service instance, and limits an SLE provider's ability to reallocate resources in real time based on system availability or other factors. This paper discusses an alternative approach to SLE service provisioning, in which individual service instances are assigned resources from a common resource pool at the time that each service instance is initialized. The paper addresses the key design elements and technical tradeoffs involved in this approach, and discusses the potential benefits with regard to load balancing, equipment reuse, and resiliency against system failure.
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Jat, Mohsin Nasir. "Time-differentiated distribution of service parts and repair materials : an investigation of service time, area partitions, and cost relations." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/28408/.
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Motivation: Manufacturers in sectors like Information Technology (IT), Automotive and Aerospace have increasingly become focused on providing after sales services. One of the forms of after sales services is to provide service parts (or spare parts) to customers within different contracted time windows. Commonly offered by large scale IT sector companies, such services are facilitated by Service Parts Logistics (SPL) systems through a network of parts stocking facilities. The number of stocking facilities in a distribution network affects the service responsiveness and service costs related to inventory, transportation and facility set-up. Higher responsiveness can be attained through increasing the number of facilities in a distribution network, which, in turn, usually increases inventory cost. Generally, studies assume that shorter service time windows result in higher costs, but there is a lack of exploration regarding how reductions in service time limits and changes in the fractions of demand for different time-based service types impact on various service related costs. Service area partitioning (or zoning) is another related issue which is unexplored in general facility location literature when considering multiple service time (or distance) constraints and both inventory and transportation costs. This study is mainly motivated by SPL systems of IT equipment manufacturers that support the provision of service parts at customer sites under different and short service time commitments in a large geographical area. The study is of a generic nature and generates insights that can be relevant for any case where the service responses are provided within different short time windows and involve the provision (or consumption) of some stocks (e.g. emergency infrastructure repairs). Aim and methodology: The aim of this work is to investigate relationships between time-based service levels, service costs and service zones/areas under a hierarchical organization and a non-hierarchical organization of service facilities. The hierarchical organization has variable capabilities to meet different time-based requirements, while the non-hierarchical organization has a uniform capability to meet the toughest requirement for the entire customer base. The investigation is mainly done through analytical, simulation and optimization modelling with the view of producing answers that provide a general understanding and practical insights rather than producing situation specific optimization models. Empirical case studies are also conducted to complement the quantitative modelling work so that the research is not divorced from the reality. The case studies point towards the motivation for the modelling study and its relevance to some of the real-world systems, and provide a broader understanding of the issues being researched. The case studies involve two multinational ICT equipment manufacturers and service provides, and a government agency responsible for providing highway emergency services in England. Key findings: The results from the modelling experiments show that under the non-hierarchical setup, where all facilities provide the full range of service-times in their respective vicinities, inventory and transportation costs are insensitive to the fractions of demand for different time-based service types. However, with an inventory sharing mechanism under the non-hierarchical setup, the increase in the proportion of demand for the service within the longer time window can increase the service availability level while also increasing the average travelling. On the other hand, under the hierarchical setup, which provides a higher level of centralization when there is demand for the service in the longer time window, inventory and transportation costs react to the proportions of demand for different time-based service types. The hierarchical setup results in higher transportation cost compared to the non-hierarchical setup, and, interestingly, does not necessarily lower the inventory level, especially when the overall demand rate is very low. The simulation of the inventory sharing mechanism under the hierarchical setup shows that, in several cases, inventory sharing can not only increase the service availability level, but can also reduce transportation cost. The analysis based on the optimization models shows that there can be cases where it is more cost effective to serve all demand, regardless of the required service time, in a similar fashion through a non-hierarchical setup. The results also show that the demand fractions for different time-based service types, and inventory and transportation costs can significantly impact on the optimum organization of service zone. There can be distinct optimum patterns of service zones depending on whether the inventory cost or the transportation cost dominates.
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Liu, Liqiang Kulkarni Vidyadhar G. "Service systems with balking based on queueing time." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,1454.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2007.Title from electronic title page (viewed Apr. 25, 2008). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Statistics and Operations Research." Discipline: Statistics and Operations Research; Department/School: Statistics and Operations Research.
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Shams, Sajjad. "Minimal lead time quotation under service level constraint." Diss., Wichita State University, 2007. http://hdl.handle.net/10057/1497.
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In today's competitive market, companies that offer a high quality service at a reasonable cost, survive the competition. A major factor contributing to high service quality is the ability to meet customers’ demand with a short lead time. Short lead time and on time delivery are two conflicting objectives. A reasonable balance between these objectives is necessary. The published research works on due date quotation make restrictive assumptions regarding the production process, considering only the production lead time, ignoring suppliers lead times, and/or rejecting some orders. No model can be found in the literature that considers all of these characteristics simultaneously. The proposed research considers a system to which orders arrive over time. Every order has a desired range of delivery date as defined by the customer. We consider order cost of delay that represents the cost of quoting due dates greater than requested. A two phase model is considered that assumes that production is constrained by a supply process. At arrival, each order is to be assigned a due date based on the status of the system. The system status is affected by internal factors including the level of WIP as well as external factors such as the supplier process. The due dates are to be assigned so that company’s objectives, defined by customer satisfaction and retention are achieved. It is desired to accept all orders, and to maximize on-time delivery of orders without placing any restriction on the behavior of the production process. The comparative results indicate that the proposed procedure is effective in quoting minimum lead times to achieve a given level of customer satisfaction.Thesis (Ph.D.)--Wichita State University, College of Engineering, Dept. of Industrial and Manufacturing Engineering
"December 2007."
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Gellman, Michael. "Quality of service routing for real-time traffic." Thesis, Imperial College London, 2007. http://hdl.handle.net/10044/1/12026.
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Shams, Sajjad Cheraghi S. Hossein. "Minimal lead time quotation under service level constraint /." Diss., A link to full text of this thesis in SOAR, 2007. http://hdl.handle.net/10057/1497.
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Antia, Shirin D., and M. Christina Rivera. "Instruction and Service Time Decisions: Itinerant Services to Deaf and Hard-of-Hearing Students." OXFORD UNIV PRESS, 2016. http://hdl.handle.net/10150/621712.
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The purpose of this study was to (a) describe the specific kinds of services provided by itinerant teachers to deaf and hard-of-hearing (DHH) students in general education settings, (b) examine the relationship between student academic performance and instructional support provided by the itinerant teacher, and (c) examine how service provision decisions are made by itinerant teachers. We used quantitative and qualitative data collected during a 5-year longitudinal study. Data were obtained from teacher questionnaires, standardized achievement tests, and interviews. Results indicated that itinerant teachers of DHH students provided direct academic instruction to 60% of students with the majority of students receiving instruction in reading and writing. They provided instruction in nonacademic areas to 80% of students with a majority of students receiving instruction in self-advocacy. Low-achieving students were the most likely to receive academic instruction from the itinerant teacher. Decisions regarding service time were influenced by student needs and performance, age, parental request, and transitions.
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Ferdean, Corina. "Enforcing service-specific replica consistency models and response time requirements for heterogeneous replicated services." Paris 6, 2006. http://www.theses.fr/2006PA066361.
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Ponge, Julien. "Model based analysis of Time-aware Web service interactions." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2008. http://tel.archives-ouvertes.fr/tel-00730187.
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Les services web gagnent de l'importance en tant que cadre facilitant l'intégration d'applications au sein et en dehors des frontières des entreprises. Il est accepté que la description d'un service ne devrait pas seulement inclure l'interface, mais aussi le protocole métier supporté par le service. Dans le cadre de ce travail, nous avons formalisé la catégorie des protocoles incluant des contraintes de temps (appelés protocoles temporisés) et étudié l'impact du temps sur l'analyse de compatibilité et de remplaçabilité. Nous avons formalisé les contraintes suivantes : les contraintes Clnvoke définissent des fenêtres de disponibilités tandis que les contraintes Mlnvoke définissent des délais d'expiration. Nous avons étendu les techniques pour l'analyse de compatibilité et de remplaçabilité entre protocoles temporisés à l'aide d'un mapping préservant la sémantique entre les protocoles temporisés et les automates temporisés, ce qui a défini la classe des automates temporisés de protocoles (PTA). Les PTA possèdent des transitions silencieuses qui ne peuvent pas être supprimées en général, et pourtant ils sont fermés par calcul du complément, ce qui rend décidable les différents types d'analyse de compatibilité et de remplaçabilité. Enfin, nous avons mis en oeuvre notre approche dans le cadre du projet ServiceMosaic, une plate-forme pour la gestion du cycle de vie des services web.
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Halvorsen, Espen Herseth. "Real-Time End-User Service Composition Using Google Wave." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for telematikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11126.
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This thesis explores Wave, a brand new communication and collaboration platform, from the perspective of end user service composition. A description of the different frameworks that are available and a study of how these can be used to create components that can be easily integrated with the platform are provided. Several examples of how the platform can be used to simplify different use cases involving multiple users collaborating on a common goal are provided. A complete solution to collaboratively organize meetings is also developed using these tools, and a detailed explanation of how one creates the necessary Wave Gadgets using web technologies like HTML, CSS and JavaScript, and the necessary back-end Wave Robots using Java are provided.
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陳偉生 and Wai-sang William Chan. "The relationship between on-time performance and service evaluation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B3126699X.
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McGowan, Jessie. "The "Just-in-Time" (JIT) information librarian consultation service." Thesis, Aberystwyth University, 2009. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511235.
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Background: This thesis is based on the “Just-in-Time information” (JIT) librarian consultation service project. The project was designed to test if a library-related service could be used to address an information gap in primary healthcare by assisting clinicians in answering their questions. The project specifically tested whether or not a librarian consultation service could have a positive impact in two delivery methods for primary care practice in Ontario, Canada. Design: Randomized controlled trial (RCT) with additional qualitative and quantitative evaluation. The literature review section includes two systematic reviews. Methods: The primary method of this thesis is RCT of clinical questions posed by primary care professionals who participated in the JIT librarian consultation service. The thesis also discusses the project’s service delivery model and its implementation, which was developed to support the RCT. Other elements broader than the RCT, such as a librarian survey, have also been developed and included to explore factors contributing to the success or failure of the librarian consultation service. It evaluates potential positive impacts in terms of costs (saving time, workload issues), patient care decision-making, and improved access to information by using such a service. Results: The JIT service was implemented and run for one year prior to the RCT phase of the project with 88 individuals who participated in the RCT. The primary outcome was time to receive a response; whether time for JIT librarians to locate information to provide a response to a question, or a participant’s time to search for the information. Librarians provided their responses to clinical questions in less than fifteen minutes. This time was quicker than the response time of the participants. Of the responses provided to intervention questions, participants rated 63% as having a highly positive impact. Of the responses provided to control questions, participants rated 24.8% as having no impact, and 44.9% as having a negative impact on decision-making. Most participants rated their level of satisfaction with the service as having a positive impact (86%) on the care they provided to their patients and 83% assessed the service as providing relevant information to their questions in an appropriate time frame. Most participants would consider using a similar service, and most participants preferred this service to be delivered by a hand-held wireless device or web interface. Discussion and conclusions: This thesis demonstrates the development and implementation of a cost-effective and user-friendly librarian consultation service that provided primary care professionals with information to assist them in answering their questions arising from patient visits. Using a librarian to respond to clinical questions may allow primary care professionals to have more time in their day, thus potentially increasing patient access to care. Participation in this RCT decreased the use of consultations with other practice physicians, return patient visits, referrals, and other actions in the control group; reductions in these areas decrease costs. The application of the RCT design by combining librarianship with health services research is unusual. The use of the response to a clinical question as the unit of randomization and allocation is also innovative.
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Anderson, Carol Lynn 1952. "Selling time : emerging trends in the consumer service industries." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14563.
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Liu, Guangtian. "An event service architecture in distributed real-time systems /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Chan, Wai-sang William. "The relationship between on-time performance and service evaluation /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B18002912.
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Di, Giuliantonio Andrea. "Data integration, real-time synchronization and RESTful Web Service." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8258/.
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Analisi e sviluppo di procedure di importazione dati per un integratore di annunci immobiliari dedicato alla vendita di soggiorni turistici in case vacanza. Il documento tratta inoltre l'implementazione di un Web Service conforme all'architettura RESTful per l'accesso e l'esportazione dei dati a soggetti terzi autorizzati tramite Digest Authentication.
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Zhanwen, Li. "Fair Service for High-Concurrent Requests." Thesis, The University of Sydney, 2007. http://hdl.handle.net/2123/1908.
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This thesis presents a new approach to ensuring fair service for highly concurrent requests. Our design uses the advantages of staged event-driven architecture (SEDA) to support high-concurrent loadings and makes use of control theory to manage the system performance. In order to guarantee the quality of service is fairly made to each request, based on SEDA, the control system for fairness is developed as a combination of a global control framework and a set of local self-tune stags. The global control framework is used to control the performance of the whole staged network at the top-level, aimed at coordinating the performance of the stages in the network. On the other hand, each self-tune stage under the control framework is built on the thread pool model, and will use automatic control theory to adjust its performance locally in order to meet the overall target performance. The automatic control system in each stage consists of an automatic modeling mechanism and a feedback module, which optimizes the controller parameters in the system automatically and guarantees the quality of performance (service rate here) for the stage at runtime. Based on mathematical proof and simulation results, our designs are implemented in a SEDA-based web server running in a dynamic loading environment. Results demonstrate that the performance of the new system in the real world is almost the same as the theoretical results. It demonstrates that the design is able to adaptively ensure the quality of service to the high-concurrent requests fairly. Compared to the original SEDA design, our design is an effective and handy approach to significantly enhancing the performance of SEDA in a variety of aspects, including fairer service, faster convergent speed, better robustness, higher accuracy and ease of deployment in various practical applications.
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Anskär, Eva. "Time flies in primary care : a study on time utilisation and perceived psychosocial work environment." Licentiate thesis, Linköpings universitet, Institutionen för medicin och hälsa, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-156119.
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Background: Time utilisation among primary care professionals has been affected by structural changes and reorganisation performed in Swedish primary care over several decades. The work situation is complex with a heavy administrative work load. The overall aim with this thesis was to describe time utilisation among staff in Swedish primary care and to investigate associations with perceived psychosocial work environment and legitimacy of work tasks. Methods: A multicentre, descriptive, cross-sectional study design was used including all staff categories in primary care i.e. registered nurses, primary care physicians, care administrators, nurse assistants and allied professionals (physiotherapists, occupational therapists, psychologists, counsellors, dieticians and chiropodists) at eleven primary care centres located in southeast Sweden. The data collection consisted of a questionnaire including a subjective estimate of workload, the Bern Illegitimate Tasks Scale (BITS) and the Copenhagen Psychosocial Questionnaire (COPSOQ). Also, a time study was performed, where the participants reported their work time based on three main categories; direct patient work tasks, indirect patient work tasks and other work tasks, each with a number of subcategories. The participants reported time spent on different work tasks, day by day during two separate weeks. Response rates were 75% for the questionnaire and 79% for the time study. Results: In paper I the time study revealed that health professionals at the primary care centres spent 37% of their work time with direct patient work tasks. All professions estimated a higher proportion of time spent directly with patients than they reported in the time study. Physicians scored highest on the psychosocial scales of quantitative demands, stress and role conflicts. The proportion of administrative work tasks was associated with role conflicts, the more administration the more role conflicts. Findings in paper II were that more than a quarter of physicians scored above the cut-off value for BITS regarding unnecessary work tasks, which was significantly more than the proportion observed in all other professions in the survey. Across all staff groups, a perception of having to perform illegitimate work tasks was associated with experiencing negative psychosocial work environment and with high proportion of administrative-related work tasks. Conclusions: Swedish primary care staff spend a limited proportion of their work time directly with patients and primary care physicians perceive the psychosocial work environment in negative terms to a greater extent than all other staff members. Allocation of work tasks has an influence on the perceived psychosocial work environment. The perception of having a large number of illegitimate work tasks affects the psychosocial work environment negatively, which might influence the perception the staff have of their professional roles. Perception of high proportion of unreasonable work tasks is associated with a high proportion of non-patient-related administration. This thesis illuminates the importance of decision makers thoroughly considering the distribution and allocation of non-patient related work tasks among staff in primary care, in order to achieve efficient use of personnel resources and favourable working conditions. Hopefully, the results of this study will contribute to further development of primary care so that medical competence will benefit patients as much as possible.Bakgrund: Under de senaste decennierna har det i svensk primärvård varit omfattande omorganisationer, vilket har påverkat arbetstidens innehåll. Arbetssituationen är komplex och omfattningen av administration har ökat. Det övergripande syftet med föreliggande studie var att beskriva arbetstidens innehåll bland personal i svensk primärvård och att undersöka samband mellan upplevd psykosocial arbetsmiljö och arbetsuppgifternas legitimitet. Metod: Studien har genomförts som en deskriptiv multicenterstudie med tvärsnittsdesign och inkluderade sjuksköterskor, läkare, vårdadministratörer, undersköterskor och övriga professioner (fysioterapeuter, arbetsterapeuter, psykologer, kuratorer, dietister och fotvårdsspecialister) vid elva vårdcentraler i sydöstra Sverige. Studien inleddes med att deltagarna ombads att besvara ett frågeformulär vars första del bestod av en skattning av hur arbetsuppgifterna var fördelade. Frågeformuläret innehöll också frågor om illegitima arbetsuppgifter; Bern Illegitimate Tasks Scale (BITS) och psykosocial arbetsmiljö; Copenhagen Psychosocial Questionnaire (COPSOQ). Därefter gjordes en tidsstudie där deltagarna fick registrera tidsåtgången för olika arbetsuppgifter, varje dag under två separata veckor. Arbetsuppgifterna delades upp i tre huvudkategorier; direkt patientarbete, indirekt patientarbete och övrigt arbete. Varje huvudkategori hade flera underkategorier. Svarsfrekvensen var 75% för frågeformuläret och 79% för tidsstudien. Resultat: Resultatet från delarbete I visar att personal i primärvård ägnade 37% av arbetstiden direkt med patienter. Alla professioner skattade den direkta patienttiden till större andel än vad tidsstudien visade. Läkare upplevde sämst psykosocial arbetsmiljö avseende kvantitativa krav, stress och rollkonflikter. Det förelåg ett samband mellan andelen administrativa arbetsuppgifter och rollkonflikter, ju mer administration desto mer rollkonflikter. I delstudie II visade resultatet att mer än en fjärdedel av läkarna upplevde en hög nivå av illegitima arbetsuppgifter avseende onödiga arbetsuppgifter, vilket var signifikant mer jämfört med andra professioner. För personalgruppen som helhet framträdde ett samband mellan upplevelsen av att ha mycket illegitima arbetsuppgifter och upplevelse av negativ psykosocial arbetsmiljö samt med hög andel administrationsrelaterade arbetsuppgifter. Konklusion: Personal i primärvård ägnar en begränsad andel av arbetstiden åt direkt patientarbete och läkare upplever sämre psykosocial arbetsmiljö än övriga professioner. Arbetstidens fördelning mellan olika arbetsuppgifter påverkar den psykosociala arbetsmiljön. Upplevelsen av att utföra en stor andel illegitima arbetsuppgifter påverkar den psykosociala arbetsmiljön negativt, vilket kan ha inverkan på hur personalen uppfattar sin professionella roll. Upplevelsen av att ha mycket oskäliga arbetsuppgifter har samband med hög andel icke patientrelaterad administration. Avhandlingen belyser vikten av att beslutsfattare noga överväger fördelningen av icke patientrelaterade arbetsuppgifter bland personal i primärvård, för att möjliggöra effektiv användning av personalresurserna och för att främja goda arbetsförhållanden. Förhoppningen är också att studiens resultat ska bidra till fortsatt utveckling av primärvården så att den medicinska kompetensen kommer patienterna till nytta i så stor omfattning som möjligt.
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Armstrong, Paul Walter. "Fact or fiction : the problem of bias in Government Statistical Service estimates of patient waiting times." Thesis, London School of Hygiene and Tropical Medicine (University of London), 2000. http://researchonline.lshtm.ac.uk/682277/.
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The cumulative likelihood of admission estimated for any given 'time-since-enrolment' depends on how we define membership of the population 'at-risk' and on how we handle right and left censored waiting times. As a result, published statistics will be biased because they assume that the waiting list is both stationary and closed and exclude all those not yet or never to be admitted. The cumulative likelihood of admission within three months was estimated using the Government Statistical Service method and compared with estimates which relaxed the assumption of stationarity and reflected variation in the numbers recruited to, and admitted from, the waiting list each quarter. The difference between the two estimates ranged from +5.5 to -9.1 percentage points among 11 Orthopaedic waiting lists in South Thames Region. In the absence of information on 'times-to-admission', exact 'times-since-enrolment' were extracted from Hospital Episode Statistics and assumed to be similarly distributed. In the absence of information on 'times-to-competing-event', the number of competing events falling in each waiting time category was estimated by differencing. A period lifetable was constructed using these approximations, census counts, counts of the number of new recruits and estimates of the number 'reset-to-zero' each quarter. The results support the view that the method used by the Government Statistical Service overestimates the cumulative likelihood of elective admission among those listed. The Government Statistical Service calculates the cumulative likelihood of admission within three months (range: 0.62-0.27) conditional on the fact of admission. Multiplying by the unconditional likelihood of being admitted (range: 0.93-0.31) estimates the cumulative likelihood of admission within three months among those listed (range: 0.55-0.12) and gives a rather different ranking of waiting list performance among 34 Orthopaedic waiting lists in South Thames Region.
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Tipirisetty, Venkat Sivendra. "Performance Analysis of Service in Heterogeneous Operational Environments." Thesis, Blekinge Tekniska Högskola, Institutionen för kommunikationssystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-13348.
Full textAbstract:
In recent years there is a rapid increase in demand for cloud services, as cloud computing has become a flexible platform for hosting microservices over the Internet. Microservices are the core elements of service oriented architecture (SOA) that facilitate the deployment of distributed software systems. As the user requires good quality of service the response time of microservices is critical in assessing the performance of the application from the end user perspective.This thesis work aims at developing a typical service architecture to facilitate the deployment of compute and I/O intensive services. The work also aims at evaluating the service times of these service when their respective subservices are deployed in heterogeneous environments with various loads.The research work has been carried out using an experimental testbed in order to evaluate the performance. The transport level performance metric called Response time is measured. It is the time taken by the server to serve the request sent by the client. Experiments have been conducted based on the objectives that are to be achieved.The results obtained from the experimentation contain the average service times of a service when it is deployed on both virtual and non-virtual environment. The virtual environment is provided by Docker containers. They also include the variation in position of their subservices. From results it can be concluded that the total service times obtained are less in case of non-virtual environments when compared to container environment.
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Krause, Christian, and Holger Giese. "Quantitative modeling and analysis of service-oriented real-time systems using interval probabilistic timed automata." Universität Potsdam, 2012. http://opus.kobv.de/ubp/volltexte/2012/5784/.
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One of the key challenges in service-oriented systems engineering is the prediction and assurance of non-functional properties, such as the reliability and the availability of composite interorganizational services. Such systems are often characterized by a variety of inherent uncertainties, which must be addressed in the modeling and the analysis approach. The different relevant types of uncertainties can be categorized into (1) epistemic uncertainties due to incomplete knowledge and (2) randomization as explicitly used in protocols or as a result of physical processes.
In this report, we study a probabilistic timed model which allows us to quantitatively reason about nonfunctional properties for a restricted class of service-oriented real-time systems using formal methods. To properly motivate the choice for the used approach, we devise a requirements catalogue for the modeling and the analysis of probabilistic real-time systems with uncertainties and provide evidence that the uncertainties of type (1) and (2) in the targeted systems have a major impact on the used models and require distinguished analysis approaches.
The formal model we use in this report are Interval Probabilistic Timed Automata (IPTA). Based on
the outlined requirements, we give evidence that this model provides both enough expressiveness for a realistic and modular specifiation of the targeted class of systems, and suitable formal methods for analyzing properties, such as safety and reliability properties in a quantitative manner. As technical means for the quantitative analysis, we build on probabilistic model checking, specifically on probabilistic time-bounded reachability analysis and computation of expected reachability rewards and costs. To carry out the quantitative analysis using probabilistic model checking, we developed an extension of the Prism tool for modeling and analyzing IPTA. Our extension of Prism introduces a means for modeling probabilistic uncertainty in the form of probability intervals, as required for IPTA. For analyzing IPTA, our Prism extension moreover adds support for probabilistic reachability checking and computation of expected rewards and costs. We discuss the performance of our extended version of Prism and compare the interval-based IPTA approach to models with fixed probabilities.Eine der wichtigsten Herausforderungen in der Entwicklung von Service-orientierten Systemen ist die Vorhersage und die Zusicherung von nicht-funktionalen Eigenschaften, wie Ausfallsicherheit und Verfügbarkeit von zusammengesetzten, interorganisationellen Diensten. Diese Systeme sind oft charakterisiert durch eine Vielzahl von inhärenten Unsicherheiten, welche sowohl in der Modellierung als auch in der Analyse eine Rolle spielen. Die verschiedenen relevanten Arten von Unsicherheiten können eingeteilt werden in (1) epistemische Unsicherheiten aufgrund von unvollständigem Wissen und (2) Zufall als Mittel in Protokollen oder als Resultat von physikalischen Prozessen. In diesem Bericht wird ein probabilistisches, Zeit-behaftetes Modell untersucht, welches es ermöglicht quantitative Aussagen über nicht-funktionale Eigenschaften von einer eingeschränkten Klasse von Service-orientierten Echtzeitsystemen mittels formaler Methoden zu treffen. Zur Motivation und Einordnung wird ein Anforderungskatalog für probabilistische Echtzeitsysteme mit Unsicherheiten erstellt und gezeigt, dass die Unsicherheiten vom Typ (1) und (2) in den untersuchten Systemen einen Ein uss auf die Wahl der Modellierungs- und der Analysemethode haben. Als formales Modell werden Interval Probabilistic Timed Automata (IPTA) benutzt. Basierend auf den erarbeiteten Anforderungen wird gezeigt, dass dieses Modell sowohl ausreichende Ausdrucksstärke für eine realistische und modulare Spezifikation als auch geeignete formale Methoden zur Bestimmung von quantitativen Sicherheits- und Zuverlässlichkeitseigenschaften bietet. Als technisches Mittel für die quantitative Analyse wird probabilistisches Model Checking, speziell probabilistische Zeit-beschränkte Erreichbarkeitsanalyse und Bestimmung von Erwartungswerten für Kosten und Vergütungen eingesetzt. Um die quantitative Analyse mittels probabilistischem Model Checking durchzuführen, wird eine Erweiterung des Prism-Werkzeugs zur Modellierung und Analyse von IPTA eingeführt. Die präsentierte Erweiterung von Prism ermöglicht die Modellierung von probabilistischen Unsicherheiten mittelsWahrscheinlichkeitsintervallen, wie sie für IPTA benötigt werden. Zur Verifikation wird probabilistische Erreichbarkeitsanalyse und die Berechnung von Erwartungswerten durch das Werkzeug unterstützt. Es wird die Performanz der Prism-Erweiterung untersucht und der Intervall-basierte IPTA-Ansatz mit Modellen mit festen Wahrscheinlichkeitswerten verglichen.
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Hyden, Eoin Andrew. "Operating system support for quality of service." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319971.
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Weindelmayer, Frederick J. "An experimental study of the suitability of Java Web services for real-time service oriented architectures." Ann Arbor, Mich. : ProQuest, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1450593.
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Thesis (M.S. in Software Engineering)--S.M.U.Title from PDF title page (viewed Mar. 16, 2009). Source: Masters Abstracts International, Volume: 46-05, page: 2736. Adviser: Frank Coyle. Includes bibliographical references.
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Edwinson, Roxanne Michelle. "Assessing Service Needs For Foster Children Automatically Enrolled Into Behavioral Health Services At Time Of Removal." Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/556953.
Full textAbstract:
The present study had an overarching objective of seeking information to better understand the service needs of children entering foster care who are universally enrolled into behavioral health services at the time of their home removal. The first specific aim was to examine how various case attributes (i.e., aspects of a child’s background, personal and familial characteristics, and CPS involvement) related to behavioral health needs at entry, represented by global functioning ratings and service intensity scores. A second specific aim was to explore the existence of natural groupings of foster youth to examine if meaningful groupings occur in relation to demographic and risk and factors. Finally, this study sought to evaluate service needs of subgroups of foster children who are typically under-referred for services. Data were collected from records of 327 school-age youth who were automatically enrolled into treatment from one community-based outpatient behavioral health provider at the time of home removal. The results of this study showed that the average school-age child entering foster care is performing in the at-risk range of global functioning (mean CGAS score of 69.23) and requires at least short-term behavioral health intervention services and/or recovery monitoring (mean CASII Composite Score of 13.1). With respect to severity of impaired functioning, the results indicated that racial background, medical history, speech problems, school grade level (e.g., <1 year, K-3,...9-12), psychological stability, and reasons for removal significantly contributed to scores of global functioning. With regard to the intensity of service needs, the findings suggested gender, historical involvement with child welfare services, foster placement, simultaneous removal of all children, history of sexualized behaviors, and global functioning predicted level of care composite scores. Subgroups of foster youth that are typically under-referred and/or under-utilize services (i.e., preschool age children, children who did not experience physical or sexual abuse, and ethnic minorities) generally did not differ in terms of functionality or service intensity ratings from their counterpart groups; the only exception being that Caucasian/Non-Hispanic youth demonstrated lower average ratings on global functioning than children who identify with other racial backgrounds. The data showed inadequate fit for examining latent classes among youth entering foster care.
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Ponge, Julien Nicolas Computer Science & Engineering Faculty of Engineering UNSW. "Model based analysis of time-aware web services interactions." Publisher:University of New South Wales. Computer Science & Engineering, 2009. http://handle.unsw.edu.au/1959.4/43525.
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Web services are increasingly gaining acceptance as a framework for facilitating application-to-application interactions within and across enterprises. It is commonly accepted that a service description should include not only the interface, but also the business protocol supported by the service. The present work focuses on the formalization of the important category of protocols that include time-related constraints (called timed protocols), and the impact of time on compatibility and replaceability analysis. We formalized the following timing constraints: CInvoke constraints define time windows of availability while MInvoke constraints define expirations deadlines. We extended techniques for compatibility and replaceability analysis between timed protocols by using a semantic-preserving mapping between timed protocols and timed automata, leading to the novel class of protocol timed automata (PTA). Specifically, PTA exhibit silent transitions that cannot be removed in general, yet they are closed under complementation, making every type of compatibility or replaceability analysis decidable. Finally, we implemented our approach in the context of a larger project called ServiceMosaic, a model-driven framework for web service life-cycle management.
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Dowling, Jason, John Welling, Loral Aerosys, Kathy Nanzetta, Toby Bennett, and Jeff Shi. "ACCELERATING REAL-TIME SPACE DATA PACKET PROCESSING." International Foundation for Telemetering, 1995. http://hdl.handle.net/10150/608429.
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International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, NevadaNASA’s use of high bandwidth packetized Consultative Committee for Space Data Systems (CCSDS) telemetry in future missions presents a great challenge to ground data system developers. These missions, including the Earth Observing System (EOS), call for high data rate interfaces and small packet sizes. Because each packet requires a similar amount of protocol processing, high data rates and small packet sizes dramatically increase the real-time workload on ground packet processing systems. NASA’s Goddard Space Flight Center has been developing packet processing subsystems for more than twelve years. Implementations of these subsystems have ranged from mini-computers to single-card VLSI multiprocessor subsystems. The latter subsystem, known as the VLSI Packet Processor, was first deployed in 1991 for use in support of the Solar Anomalous & Magnetospheric Particle Explorer (SAMPEX) mission. An upgraded version of this VMEBus card, first deployed for Space Station flight hardware verification, has demonstrated sustained throughput of up to 50 Megabits per second and 15,000 packets per second. Future space missions including EOS will require significantly higher data and packet rate performance. A new approach to packet processing is under development that will not only increase performance levels by at least a factor of six but also reduce subsystem replication costs by a factor of five. This paper will discuss the development of a next generation packet processing subsystem and the architectural changes necessary to achieve a thirty-fold improvement in the performance/price of real-time packet processing.
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Clauß, Matthias. "Überwachung von Diensten (Service Monitoring)." Universitätsbibliothek Chemnitz, 2002. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200201079.
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Gemeinsamer Workshop von Universitaetsrechenzentrum und Professur Rechnernetze und verteilte Systeme der Fakultaet fuer Informatik der TU Chemnitz.
Service Monitoring ist eine Voraussetzung für zuverlässige Dienste.
Ausgehend von einer Einführung in die Techniken des Real-Time Monitoring wird
das System "Big Brother" und der Einsatz im
Universitätsrechenzentrum der TUC vorgestellt.
Abschliesend werden einige Aspekte der Benachrichtigung beim
Auftreten kritischer Ereignisse und Zustände diskutiert.
bei der Alarmierung
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Hashimura, Kanzunori. "Investigation of service-machine time requirements for automated yarn creeling." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/16731.
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Gamble, Carl Jeffrey. "Design time detection of architectural mismatches in service oriented architectures." Thesis, University of Newcastle Upon Tyne, 2011. http://hdl.handle.net/10443/1241.
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Service Oriented Architecture (SOA) is a software component paradigm that has the potential to allow for exible systems that are loosely coupled to each other. They are discoverable entities that may be bound to at run time by a client who is able to use the service correctly by referring to the service's description documents. Assumptions often have to be made in any design process if the problem domain is not fully speci ed. If those decisions are about the software architecture of that component and it is inserted into a system with di ering and incompatible assumptions then we say that an architectural mismatch exists. Architectural styles are a form of software reuse. They can simply be used by referring to a name such as \client-server" or \pipe and lter", where these names may conjure up topologies and expected properties in the architects mind. They can also however be more rigorously de ned given the right software environment. This can lead to a vocabulary of elements in the system, de ned properties of those elements along with rules and analysis to either show correctness of an implementation or reveal some emergent property of the whole. SOA includes a requirement that the service components make available descriptions of themselves, indicating how they are to be used. With this in mind and assuming we have a suitable description of the client application it should be the case that we can detect architectural mismatches when designing a new system. Here designing can range from organising a set of existing components into a novel con guration through to devising an entirely new set of components for an SOA. This work investigates the above statement using Web Services as the SOA implementation and found that, to a degree, the above statement is true. The only element of description required for a web service is the Web Service Description Language (WSDL) document and this does indeed allow the detection of a small number of mismatches when represented using our minimal web service architectural style. However from the literature we nd that the above mismatches are only a subset of those that we argue should be detectable. In response to this we produce an enhanced web service architectural style containing properties and analysis supporting the detection of this more complete set of mismatches and demonstrate its e ectiveness against a number of case studies.
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MONTEIRO, RUHAN DOS REIS. "A REAL-TIME REASONING SERVICE FOR THE INTERNET OF THINGS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2018. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=36169@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE EXCELENCIA ACADEMICA
O crescimento da Internet das Coisas (IoT) nos trouxe a oportunidade de criar aplicações em diversas áreas com o uso de sensores e atuadores. Um dos problemas encontrados em sistemas de IoT é a dificuldade de adicionar relações semânticas aos dados brutos produzidos por estes sensores e conseguir inferir novos fatos a partir destas relações. Além disso, devido à natureza destes sistemas, os dados produzidos por eles, conhecidos como streams, precisam ser analisados em tempo real. Streams são uma sequência de elementos de dados com variação de tempo e que não devem ser tratados como dados a serem armazenados para sempre e consultados sob demanda. Os dados em streaming precisam ser consumidos rapidamente por meio de consultas contínuas que analisam e produzem novos dados relevantes. A capacidade de inferir novas relações semânticas sobre dados em streaming é chamada de inferência sobre streams. Nesta pesquisa, propomos um modo semântico e um mecanismo para processamento e inferência sobre streams em tempo real baseados em Processamento de Eventos Complexos (CEP), RDF (Resource Description Framework) e OWL (Web Ontology Language). Apresentamos um middleware que suporta uma inferência contínua sobre dados produzidores por sensores. As principais vantagens de nossa abodagem são: (a) considerar o tempo como uma relação-chave entre a informação; (b) processamento de fluxo por ser implementado usando o CEP; (c) é geral o suficiente para ser aplicado a qualquer sistema de gerenciamento de fluxo de dados (DSMS). Foi desenvolvido no Laboratório de Colaboração Avançada (LAC) utlizando e um estudo de caso no domínio da detecção de incêndio é conduzido e implementado, elucidando o uso de inferência em tempo real sobre streams.
The growth of the Internet of Things (IoT) has brought the opportunity to create applications in several areas, with the use of sensors and actuators. One of the problems encountered in IoT systems is the difficulty of adding semantic relations to the raw data produced by the sensors and being able to infer new facts from these relations. Moreover, due to the fact that many IoT applications are online and need to react instantly on sensor data collected by them, they need to be analyzed in real-time. Streams are a sequence of time-varying data elements that should not be stored forever and queried on demand. Streaming data needs to be consumed quickly through ongoing queries that continue to analyze and produce new relevant data, i.e. stream of output/result events. The ability to infer new semantic relationships over streaming data is called Stream Reasoning. We propose a semantic model and a mechanism for real-time data stream processing and reasoning based on Complex Event Processing (CEP), RDF (resource description structure) and OWL (Web Ontology Language). This work presents a middleware service that supports continuous reasoning on data produced by sensors. The main advantages of our approach are: (a) to consider time as a key relationship between information; (b) flow processing can be implemented using CEP; (c) is general enough to be applied to any data flow management system (DSMS). It was developed in the Advanced Collaboration Laboratory (LAC) and a case study in the field of fire detection is conducted and implemented, elucidating the use of real-time inference on streams.
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Neely, Michael J. (Michael James) 1975. "Queue occupancy in single-server deterministic service time tree networks." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9318.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1999.Includes bibliographical references (p. 167).
Tree networks of single server, deterministic service time queues are often used as models for packet flow in systems with ATM traffic. In this thesis, we present methods of analyzing packet occupancy in these systems. We develop general theorems which enable the analysis of individual nodes within a multi-stage system to be reduced to the analysis of a simpler single-stage or 2- stage equivalent model. In these theorems, we make very few assumptions about the nature of the exogenous input processes themselves, and hence our results apply to a variety of input sources. In particular, we treat three input source cases: bursty on/off inputs, periodic continuous bit rate (CBR) inputs, and discrete time Generalized Independent (GI) inputs. For each of these input sources, we derive mean queue lengths for individual nodes and aggregate occupancy distribution functions for multi-stage systems. For GI-type inputs (which includes memoryless inputs), we derive explicit expressions for the means and variances of packet occupancy in any node of a multi-stage, deterministic service time tree network. We also create a general definition of a "distributable input," which includes any collection of M sources which run independently and are identically distributed (iid) according to some arbitrary type of arrival process (in particular, this includes periodic CBR sources). We demonstrate that the expected occupancy of a single-stage system is a convex, monotonic function of the distributable input loading. Furthermore, the expected occupancy of any node within a multi-stage tree network is a concave function of the multiple exogenous input loadings at the upstream nodes.
by Michael J. Neely.
S.M.
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Blake, Betancourt Juan Jamie. "Air time : another measure of the quality of passenger service." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/38331.
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Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, June 2006.Page 83 blank.
Includes bibliographical references.
The proposal of a new metric called "Air Time" and its various components, show the advantage of having a broader perspective of the travel process of airline passengers. Travel time is basically affected by three different factors. These factors are the length of the flight, the frequency of the flight and the day on which this flight is operated. Particular attention is paid to the ground side component of the Air Time and on how this component is affected by the three variables mentioned above. The Air Time offers the possibility of making comparisons of the different parts of the travel process while looking at the whole picture of it. These comparisons range from comparing two airlines operating on the same route to compare the performance of the different stages of the travel process in different times. The relation of these three variables to the Air Time is well determined and statistical analysis is done in order to show how each of these variables affects the Air Time and its various components. As a result of the statistical analysis, at the end is possible to estimate the ground side component of the Air Time for a given flight based on its haul, frequency and day of operation. among airlines.
(cont.) The information provided by the Air Time and its different components, can assist airlines and airport as an additional tool in operations planning. Also, the information provided by this new metric can benefit the public by allowing people to better understand what it really means, in terms of time, to engage in a flight with a particular airline and thus improving the competition
by Juan Jamie Blake Betancourt.
S.M.
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Eccles, Mitchell John. "Pragmatic development of service based real-time change data capture." Thesis, Aston University, 2013. http://publications.aston.ac.uk/19148/.
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This thesis makes a contribution to the Change Data Capture (CDC) field by providing an empirical evaluation on the performance of CDC architectures in the context of realtime data warehousing. CDC is a mechanism for providing data warehouse architectures with fresh data from Online Transaction Processing (OLTP) databases. There are two types of CDC architectures, pull architectures and push architectures. There is exiguous data on the performance of CDC architectures in a real-time environment. Performance data is required to determine the real-time viability of the two architectures. We propose that push CDC architectures are optimal for real-time CDC. However, push CDC architectures are seldom implemented because they are highly intrusive towards existing systems and arduous to maintain. As part of our contribution, we pragmatically develop a service based push CDC solution, which addresses the issues of intrusiveness and maintainability. Our solution uses Data Access Services (DAS) to decouple CDC logic from the applications. A requirement for the DAS is to place minimal overhead on a transaction in an OLTP environment. We synthesize DAS literature and pragmatically develop DAS that eciently execute transactions in an OLTP environment. Essentially we develop effeicient RESTful DAS, which expose Transactions As A Resource (TAAR). We evaluate the TAAR solution and three pull CDC mechanisms in a real-time environment, using the industry recognised TPC-C benchmark. The optimal CDC mechanism in a real-time environment, will capture change data with minimal latency and will have a negligible affect on the database's transactional throughput. Capture latency is the time it takes a CDC mechanism to capture a data change that has been applied to an OLTP database. A standard definition for capture latency and how to measure it does not exist in the field. We create this definition and extend the TPC-C benchmark to make the capture latency measurement. The results from our evaluation show that pull CDC is capable of real-time CDC at low levels of user concurrency. However, as the level of user concurrency scales upwards, pull CDC has a significant impact on the database's transaction rate, which affirms the theory that pull CDC architectures are not viable in a real-time architecture. TAAR CDC on the other hand is capable of real-time CDC, and places a minimal overhead on the transaction rate, although this performance is at the expense of CPU resources.
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Parry, Dominic Charles. "CREWS : a Component-driven, Run-time Extensible Web Service framework." Thesis, Rhodes University, 2004. http://eprints.ru.ac.za/74/.
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Wang, Jason Randle. "Priority time: Employee coping strategies for service delivery to undergraduates." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/284252.
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Students, faculty, and administrators are favored research subjects when studying colleges and universities. Often ignored are the frontline employees who deliver service directly to students. To students receiving service, these employees are functionally the voice of the University, yet are often not considered by faculty or administrators when making changes that shape the University as a whole. This case study of four departments at one large, public, Research-I University seeks to understand frontline employee perspectives on time, work, and clients, as well as coping strategies for service delivery. The literatures drawn on include, service delivery methods and trends, time use and management, trends in higher education, and human resources management. Policy recommendations are made in the final chapter.
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Roscoe, Timothy. "The structure of a multi-service operating system." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363305.
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Prathipati, Rajesh Babu. "Energy efficient scheduling techniques for real-time embedded systems." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/194.
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Battery-powered portable embedded systems have been widely used in many applications. These embedded systems have to concurrently perform a multitude of complex tasks under stringent time constraints. As these systems become more complex and incorporate more functionality, they became more power-hungry. Thus, reducing power consumption and extending battery lifespan while guaranteeing the timing constraints has became a critical aspect in designing such systems. This gives rise to three aspects of research: (i) Guaranteeing the execution of the hard real-time tasks by their deadlines, (ii) Determining the minimum voltage under which each task can be executed, and (iii) Techniques to take advantage of run-time variations in the execution times of tasks. In this research, we present techniques that address the above aspects in single and multi processor embedded systems. We study the performance of the proposed techniques on various benchmarks in terms of energy savings.
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Derrick, Sonja Anna. "Time well spent : modelling education and service activities of junior doctors under the European Working Time Directive." Thesis, University of Plymouth, 2009. http://hdl.handle.net/10026.1/2146.
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A number of professional groups face the conflict of providing a service to their organisation as a whole, and wider to its clients, while continuing to develop their skills and knowledge professionally, in order to be able to perform effectively in their current role as well as future ones, within a certain amount of time available to them. The introduction of reduced-hours legislation under the European Working Time Directive for junior doctors has posed an organisational problem for NHS Trusts in the UK, who need to reconcile the training and service needs of the profession and the service within the more confined resource of time. This research has identified a distinct lack of clarification of the concepts of training and service in the literature, and no understanding of how these are linked to the activities that junior doctors participate, nor to the working system in which they exist. It uses a constructivist mixed method approach to exploring what is meant by training and service, how this is linked to the operational day-to-day activities in the working lives of junior doctors and how changes in these working and training practices affect the nature and type of service and training activity for the medical workforce and organisational system as a whole. Its contributions to knowledge are multifaceted, ranging from the contributions to exploring the concepts of "training" and "service" and how they relate to activity, an understanding of the system, Its entities and relationships, as well as a new application of a business modelling technique. While it uses junior doctors at Plymouth Hospitals NHS Trust as the specific area for study, Its findings are generalisable to the organisational context of other NHS Trusts, as well as other professional groups.
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Fan, Jianyuan. "Real-time video transmission over ABR service using rate control algorithm." Thesis, University of Ottawa (Canada), 2002. http://hdl.handle.net/10393/6373.
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The ATM Available Bit Rate (ABR) service category was initially designed to support non-real-time applications. However it is possible for ABR to support real-time applications, such as multimedia applications, by taking advantage of the inherent traffic control capability of ABR and the adaptation ability of real-time applications. Using a proper switch traffic control algorithm, ABR queues in the switches can be kept within acceptable bounds and therefore a loose end-to-end delay bound can be guaranteed. FASTRAC is a simple, scalable, provably stable, explicit rate computation scheme for flow control in computer networks. The main objective of the present thesis is to study how to transmit real-time video over ABR service using FASTRAC rate control algorithm. Using OPNET simulation tool, we study the effect of Resource Management (RM) cell interval, control delay and stability factor. With the simulation experiments, we study the performance of the rate control algorithm when it supports real-time video applications using fixed weight allocation scheme. To overcome the problems with the fixed weight allocation scheme, we introduce a dynamic weight allocation scheme, allowing us to improve the rate allocation among all ABR connections. Our simulation results also show that the spare link capacity can be further utilized by transmitting non-real-time applications without affecting the QoS of the real-time video applications.
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IRALA, ADRIAN. "The Comeback of the Cargo Bike: This Time as a Service?" Thesis, KTH, Skolan för industriell teknik och management (ITM), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-224841.
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Sim, Michel. "Quality of service management in a multimedia real-time transport protocol." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq31249.pdf.
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Blair, Christopher Douglas. "Multipoint communication protocols : a transport service for real-time group interaction." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359664.
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Leulseged, Amare Mengesha. "Probabilistic schedulability and quality of service analysis in real-time systems." Thesis, London South Bank University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435238.
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Dobre, Dan. "Time-Efficient Asynchronous Service Replication." Phd thesis, 2010. https://tuprints.ulb.tu-darmstadt.de/2300/1/thesis.pdf.
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Modern critical computer applications often require continuous and correct operation despite the failure of critical system components. In a distributed system, fault-tolerance can be achieved by creating multiple copies of the functionality and placing them at different processes. The core constitutes a distributed protocol run among the processes whose goal is to provide the end user with the illusion of sequentially accessing a single correct copy. Not surprisingly, the efficiency of the distributed protocol used has a severe impact on the application performance. This thesis investigates the cost associated with implementing fundamental abstractions constituting the core of service replication in asynchronous distributed systems, namely (a) consensus and (b) the read/write register. The main question addressed by this thesis is how efficient implementations of these abstractions can be. The focus of the thesis lies on time complexity (or latency) as the main effciency metric, expressed as the number of communication steps carried out by the algorithm before it terminates. Besides latency, important cost factors are the resilience of an algorithm (i.e. the fraction of failures tolerated) and its message complexity (the number of messages exchanged). Consensus is perhaps the most fundamental problem in distributed computing. In the consensus problem, processes propose values and unanimously agree on one of the proposed values. In a purely asynchronous system, in which there is no upper bound on message transmission delays, consensus is impossible if a single process may crash. In practice however, systems are not asynchronous. They are timely in the common case and exhibit asynchronous behavior only occasionally. This observation has led to the concept of unreliable failure detectors to capture the synchrony conditions sufficient to solve consensus. This thesis studies the consensus problem in asynchronous systems in which processes may fail by crashing, enriched with unreliable failure detectors. It determines how quickly consensus can be solved in the common case, characterized by stable executions in which all failures have reliably been detected, settling important questions about consensus time complexity. Besides consensus, the read/write register abstraction is essential to sharing information in distributed systems, also referred to as distributed storage for its importance as a building-block in practical distributed storage and le systems. We study fault-tolerant read/write register implementations in which the data shared by a set of clients is replicated on a set of storage base objects. We consider robust storage implementations characterized by (a) wait-freedom (i.e. the fact the read/write operations invoked by correct clients always return) and (b) strong consistency guarantees despite a threshold of object failures. We allow for the most general type of object failure, Byzantine, without assuming authenticated data to limit the adversary. In this model, we determine the worst-case time complexity of accessing such a robust storage, closing several fundamental complexity gaps.
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Huang, Yi-ning, and 黃一寧. "Optimal pricing of computer service facility with multistage service time." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/37461120316116149068.
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碩士國立中央大學
工業管理研究所
95
The objective of this paper is to examine the impact of introducing a multistage distribution in the computer service facility. Cheng(1997) had derived the model which considered the circumstances of computer systems subject to breakdowns and was described with exponential distribution. However, in practice, services provided by a computing center to a user might not be consisted of a single step but often several steps. Consequently we consider a more general distribution to relate the operation of computer systems. Under the same condition of systems breakdown discussed in Cheng(1997), we discuss the pricing and capacity decision of the service facility, renew the model of users’ expected waiting time in the system, and analysis the results between different parameters setting. We compare our model with Cheng(1997) numerically and graphically, and discuss the implication of these different results.
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Chien, Jui-Chi, and 簡睿祁. "Consider Service Time for Vehicle Routing Problem in Airport Shuttle Service." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/89810243021565331361.
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碩士國立雲林科技大學
工業工程與管理系
104
In recent years, since the airlines increase the routes between China and Taiwan, and the low-cost airlines prospered, passengers entering and leaving Taiwan increase significantly. The vehicle transportation system which connects suburb airport and resident is more important. The service model developed in this study considers door-to-door customers who require pickup and delivery service by shuttles between airport and appointed destinations. Through shared-ride service, customers can possess the convenience of door-to-door service with cheaper fare than taxi. Controlling pickup and delivery times are important to the airport shuttle service providers. Therefore, this study considers three kinds of time windows to make sure customer can catch the plane on time and satisfy the waiting time. The objective function of the proposed mathematical model is to minimize the total cost which includes total distance cost, vehicle activated cost, cost of customer riding time, and cost of customer waiting time. Service time is transformed to cost, it is believed that customer satisfaction can be considered. Solution algorithm using threshold accepting method is to improve vehicle routing problem in airport shuttle service. In sensitivity analysis, this study test different shuttle operating models and control strategies, the results indicate that combination shuttle mode proposed in this study is a better choice.