published_or_final_version / Computer Science / Master / Master of Philosophy

Cyber-physical systems (CPS) are systems featuring a tight combination of, and coordination between, the system’s computational and physical elements. Cyber-physical systems include systems ranging from critical infrastructure such as a power grid and transportation system to health and biomedical devices. System reliability, i.e., the ability of a system to perform its intended function under a given set of environmental and operational conditions for a given period of time, is a fundamental requirement of cyber-physical systems. An unreliable system often leads to disruption of service, financial cost and even loss of human life. An important and prevalent type of cyber-physical system meets the following criteria: processing large amounts of data; employing software as a system component; running online continuously; having operator-in-the-loop because of human judgment and an accountability requirement for safety critical systems. This thesis aims to improve system reliability for this type of cyber-physical system. To improve system reliability for this type of cyber-physical system, I present a system evaluation approach entitled automated online evaluation (AOE), which is a data-centric runtime monitoring and reliability evaluation approach that works in parallel with the cyber-physical system to conduct automated evaluation along the workflow of the system continuously using computational intelligence and self-tuning techniques and provide operator-in-the-loop feedback on reliability improvement. For example, abnormal input and output data at or between the multiple stages of the system can be detected and flagged through data quality analysis. As a result, alerts can be sent to the operator-in-the-loop. The operator can then take actions and make changes to the system based on the alerts in order to achieve minimal system downtime and increased system reliability. One technique used by the approach is data quality analysis using computational intelligence, which applies computational intelligence in evaluating data quality in an automated and efficient way in order to make sure the running system perform reliably as expected. Another technique used by the approach is self-tuning which automatically self-manages and self-configures the evaluation system to ensure that it adapts itself based on the changes in the system and feedback from the operator. To implement the proposed approach, I further present a system architecture called autonomic reliability improvement system (ARIS). This thesis investigates three hypotheses. First, I claim that the automated online evaluation empowered by data quality analysis using computational intelligence can effectively improve system reliability for cyber-physical systems in the domain of interest as indicated above. In order to prove this hypothesis, a prototype system needs to be developed and deployed in various cyber-physical systems while certain reliability metrics are required to measure the system reliability improvement quantitatively. Second, I claim that the self-tuning can effectively self-manage and self-configure the evaluation system based on the changes in the system and feedback from the operator-in-the-loop to improve system reliability. Third, I claim that the approach is efficient. It should not have a large impact on the overall system performance and introduce only minimal extra overhead to the cyber- physical system. Some performance metrics should be used to measure the efficiency and added overhead quantitatively. Additionally, in order to conduct efficient and cost-effective automated online evaluation for data-intensive CPS, which requires large volumes of data and devotes much of its processing time to I/O and data manipulation, this thesis presents COBRA, a cloud-based reliability assurance framework. COBRA provides automated multi-stage runtime reliability evaluation along the CPS workflow using data relocation services, a cloud data store, data quality analysis and process scheduling with self-tuning to achieve scalability, elasticity and efficiency. Finally, in order to provide a generic way to compare and benchmark system reliability for CPS and to extend the approach described above, this thesis presents FARE, a reliability benchmark framework that employs a CPS reliability model, a set of methods and metrics on evaluation environment selection, failure analysis, and reliability estimation. The main contributions of this thesis include validation of the above hypotheses and empirical studies of ARIS automated online evaluation system, COBRA cloud-based reliability assurance framework for data-intensive CPS, and FARE framework for benchmarking reliability of cyber-physical systems. This work has advanced the state of the art in the CPS reliability research, expanded the body of knowledge in this field, and provided some useful studies for further research.

In recent years, the focus of cartographic research has shifted from the cartographic communication paradigm to the scientific visualization paradigm. With this, there has been a resurgence of cognitive research that is invaluable in guiding the design and evaluation of effective cartographic visualization tools. The design of new tools that allow effective visual exploration of spatial data and data quality information in a resource management setting is critical if decision-makers and policy setters are to make accurate and confident decisions that will have a positive long-term impact on the environment. The research presented in this dissertation integrates the results of previous research in spatial cognition, visualization of spatial information and on-line map use in order to explore the design, development and experimental testing of four interactive visualization tools that can be used to simultaneously explore spatial data and data quality. Two are traditional online tools (side-by-side and sequenced maps) and two are newly developed tools (an interactive "merger" bivariate map and a hybrid o f the merger map and the hypermap). The key research question is: Are interactive visualization tools, such as interactive bivariate maps and hypermaps, more effective for communicating spatial information than less interactive tools such as sequenced maps? A methodology was developed in which subjects used the visualization tools to explore a forest species composition and associated data quality map in order to perform a range of map-use tasks. Tasks focused on an imaginary land-use conflict for a small region of mixed boreal forest in Northern Alberta. Subject responses in terms of performance (accuracy and confidence) and preference are recorded and analyzed. Results show that theory-based, well-designed interactive tools facilitate improved performance across all tasks, but there is an optimal matching between specific tasks and tools. The results are generalized into practical guidelines for software developers. The use of confidence as a measure of map-use effectiveness is verified. In this experimental setting, individual differences (in terms of preference, ability, gender etc.) did not significantly affect performance.

Web applications have become a large segment of the software development domain but their rapid rise in popularity has far exceeded the support in software engineering. There are many tools and techniques for web application development, but the developer must still learn and use many complex protocols and languages. Products still closely bind data operations, business logic, and the user interface, limiting integration and interoperability. This thesis introduces an innovative new presentation service to help web application developers create better applications faster, and help them build high quality web user interfaces. This service acts as a broker between web browsers and applications, adding value with programming-language independent object-oriented technology. The second innovation is a generic graphics applet (GGA) component for the web browser user interface. This light component provides interactive graphics support for the creation of business charts, maps, diagrams, and other graphical displays in web applications. The combination of a presentation service program (BUS) and the GGA is explored in a series of experiments to evaluate their ability to improve web applications. The experiments provide evidence that the BUS and GGA technology enhances web application designs.

Orientadores: Maria Cecilia Calani Baranauskas, Claudia Maria Bauzer Medeiros / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-07T08:38:34Z (GMT). No. of bitstreams: 1 Schimiguel_Juliano_D.pdf: 17588489 bytes, checksum: 9550a21b1f40b24668f4ab2d6d270dda (MD5) Previous issue date: 2006 / Resumo: Sistemas de Informação Geográfica (SIG) são categorias de software que permitem a manipulação, gerenciamento e visualização de dados geo referenciados. O termo georeferenciado denota associação a um sistema de coordenadas geográficas. Existem inúmeras categorias de aplicações SIG. em diferentes escalas e domínios, abrangendo desde temas urbanos até ambientais. Aplicações de Sistemas de Informação Geográfica na Web, neste trabalho denominadas "aplicações SIG Web", são sistemas onde a 'informação geográfica' pode estar dispersa em diferentes locais e sua manipulação via SIG ocorre através da Internet. A importância de SIG Web direcionados a sistemas agrícolas, foco deste trabalho, advém do fato de funcionarem como um ferramental útil para usuários que trabalham direta ou indiretamente no domínio: agricultores, agrônomos, cooperativas agrícolas, órgãos governamentais ligados à área. Interfaces de Usuário em SIG Web têm sido desenvolvidas sem o uso de práticas e critérios que considerem especificidades desse domínio de aplicação e a diversidade de usuários na web. A qualidade da interface dessas aplicações influencia diretamente o seu uso. Este trabalho se propõe a conceituar qualidade no contexto de interfaces de aplicações SIG Web. investigando tanto o produto - a interface de aplicações SIG Web - quanto o processo de design de interfaces de tais aplicações. Estas duas perspectivas formam a base de recomendações para a avaliação de suas interfaces de aplicações. O resultado principal do trabalho é a definição de um framework de bases semióticas para orientar designers e partes interessadas no design de aplicações SIG Web na avaliação de interfaces de tais aplicações. Esse framework organiza um espaço de análise que contém as recomendações identificadas nos contextos de avaliação do produto e de processo de design de aplicações SIG Web. Ele foi desenvolvido e testado utilizando um conjunto de aplicações e estudos de caso reais, no domínio agrícola. / Abstract: Geographic Information Systems (GIS) are pieces of software that allow manipulation, management and visualization of georeferenced data, where the term "georeferencing" denotes association with geographic coordinates. There are countless kinds of applications that use GIS, for different domains and using distinct geographic scales, ranging from urban to environmental issues. This thesis uses the expression "Web GIS applications" to denote applications running on Geographic Information Systems. They are systems where the geographic information may be distributed over several sites, and is manipulated by users on the Internet, using a GIS. This work is centered on Web GIS applications for the agricultural domain. The relevance of these applications is based on the fact that they serve as a basic decision platform for users that directly or indirectly work in this domain: farmers, agronomers, cooperatives or government instances. Web GIS User Interfaces have long been developed without considering practices and criteria that take into account the domain's specificity, or the wide spectrum of Web users. The quality of these interfaces has a major impact in the use of these applications. This thesis is centered on analyzing the issue of the quality of Web GIS application interfaces, under two perspectives: the product - the interface itself: and the design process of these interfaces. The main contribution of this work is a definition of a framework based on semiotics that guides Web GIS application designers in the evaluation of the interfaces of these applications. This framework includes a set of procedures, as well as a set of recommendations to be followed by designers in order to improve interface quality. The framework was developed and validated using several real life applications, for the agricultural domain. / Doutorado / Sistemas de Informação / Doutor em Ciência da Computação

In recent years, the focus of cartographic research has shifted from the cartographic communication paradigm to the scientific visualization paradigm. With this, there has been a resurgence of cognitive research that is invaluable in guiding the design and evaluation of effective cartographic visualization tools. The design of new tools that allow effective visual exploration of spatial data and data quality information in a resource management setting is critical if decision-makers and policy setters are to make accurate and confident decisions that will have a positive long-term impact on the environment. The research presented in this dissertation integrates the results of previous research in spatial cognition, visualization of spatial information and on-line map use in order to explore the design, development and experimental testing of four interactive visualization tools that can be used to simultaneously explore spatial data and data quality. Two are traditional online tools (side-by-side and sequenced maps) and two are newly developed tools (an interactive "merger" bivariate map and a hybrid o f the merger map and the hypermap). The key research question is: Are interactive visualization tools, such as interactive bivariate maps and hypermaps, more effective for communicating spatial information than less interactive tools such as sequenced maps? A methodology was developed in which subjects used the visualization tools to explore a forest species composition and associated data quality map in order to perform a range of map-use tasks. Tasks focused on an imaginary land-use conflict for a small region of mixed boreal forest in Northern Alberta. Subject responses in terms of performance (accuracy and confidence) and preference are recorded and analyzed. Results show that theory-based, well-designed interactive tools facilitate improved performance across all tasks, but there is an optimal matching between specific tasks and tools. The results are generalized into practical guidelines for software developers. The use of confidence as a measure of map-use effectiveness is verified. In this experimental setting, individual differences (in terms of preference, ability, gender etc.) did not significantly affect performance. / Arts, Faculty of / Geography, Department of / Graduate

This research tested the effect of unique combinations of interface coding and presentation techniques for the redesign of the AN/SLQ-32(V) Display Control Console (DCC). The DCC provides Navy operators with bearing and threat information for radar emitters. The task of emitter identification was used to test potential redesigns. There is no research to substantiate the current or possible redesign solutions. Thus, Experiment 1 tested potential design modifications for the DCC. The factorial combination of the following comparisons yielded eight possible design solutions: color versus monochrome coding, polar (bearing only) versus range (bearing and range) presentation, and geometric symbols versus icons. Each design was tested in three conditions of emitter density: low, medium, and high. Researchers have evaluated color and symbology with consideration to emitter display systems, but without considering how range information and emitter density effect performance. Results indicate that range information improves performance by 60%. The addition of color and the new icons also significantly improves performance (17% and 15%, respectively) as compared to the current DCC configuration (Polar, Geometric, and Monochrome). Performance was measured by time to complete a task, errors, and subjective workload. Experiment 2 considered redesign solutions not restricted to the existing hardware or software. Although discussed frequently in the interface literature, performance differences between direct-manipulation and command-key interfaces have not been validated. In this study, two interfaces were constructed to take advantage of direct manipulation and command-key interaction (DMI and CKI, respectively) styles while adding a computer-aided emitter library management system, an on-screen oscilloscope, a polygon display of emitter parameters, range information, icons, increased usage of color, and other design changes. Results indicate no differences between the CKI and DMI for the time required to perform the task or for subjective workload. Although both interfaces were designed to take advantage of their respective features, operators did not perform faster with the CKI than with the DMI. However, operators did have significantly fewer errors with the DMI than with the CKI. When compared to the existing DCC and the Range/Color/Iconic design, operators using the CKI and DMI: (1) processed twice as many emitters, (2) reduced one type of error by 50% (CKI) or 67% (DMI), (3) reduced a second type of error to zero, (4) decreased subjective workload by over 50%, and (5) maintained a higher level of performance regardless of emitter density. / Ph. D.

The promise of service oriented computing, and the availability of Web services promote the delivery and creation of new services based on existing services, in order to meet new demands and new markets. As Web and internet based services move into Clouds, inter-dependency of services and their complexity will increase substantially. There are standards and frameworks for specifying and composing Web Services based on functional properties. However, mechanisms to individually address non-functional properties of services and their compositions have not been well established. Furthermore, the Cloud ontology depicts service layers from a high-level, such as Application and Software, to a low-level, such as Infrastructure and Platform. Each component that resides in one layer can be useful to another layer as a service. It hints at the amount of complexity resulting from not only horizontal but also vertical integrations in building and deploying a composite service. To meet the requirements and facilitate using Web services, we first propose a WSDL extension to permit specification of non-functional or Quality of Service (QoS) properties. On top of the foundation, the QoS-aware framework is established to adapt publicly available tools for Web services, augmented by ontology management tools, along with tools for performance modeling to exemplify how the non-functional properties such as response time, throughput, or utilization of services can be addressed in the service acquisition and composition process. To facilitate Web service composition standards, in this work we extended the framework with additional qualitative information to the service descriptions using Business Process Execution Language (BPEL). Engineers can use BPEL to explore design options, and have the QoS properties analyzed for the composite service. The main issue in our research is performance evaluation in software system and engineering. We researched the Web service computation as the first half of this dissertation, and performance antipattern detection and elimination in the second part. Performance analysis of software system is complex due to large number of components and the interactions among them. Without the knowledge of experienced experts, it is difficult to diagnose performance anomalies and attempt to pinpoint the root causes of the problems. Software performance antipatterns are similar to design patterns in that they provide what to avoid and how to fix performance problems when they appear. Although the idea of applying antipatterns is promising, there are gaps in matching the symptoms and generating feedback solution for redesign. In this work, we analyze performance antipatterns to extract detectable features, influential factors, and resource involvements so that we can lay the foundation to detect their presence. We propose system abstract layering model and suggestive profiling methods for performance antipattern detection and elimination. Solutions proposed can be used during the refactoring phase, and can be included in the software development life cycle. Proposed tools and utilities are implemented and their use is demonstrated with RUBiS benchmark.

Orientador: Maria Cecilia Calani Baranauskas / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-21T17:08:06Z (GMT). No. of bitstreams: 1 Santana_VagnerFigueredode_D.pdf: 4477858 bytes, checksum: f4c115f4395355870c66c81a065a8e3f (MD5) Previous issue date: 2012 / Resumo: ...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital. / Abstract: ...Note: The complete abstract is available with the full electronic document / Doutorado / Avaliação de interfaces de usuario / Doutor em Ciência da Computação

The purpose of this study is to determine whether the style of a user interface (i.e., its look and feel) has an effect on the usability of a synchronous computer supported cooperative work (CSCW) environment for delivering Internet-based collaborative content. The problem motivating this study is that people who are located in different places need to be able to communicate with one another. One way to do this is by using complex computer tools that allow users to share information, documents, programs, etc. As an increasing number of business organizations require workers to use these types of complex communication tools, it is important to determine how users regard these types of tools and whether they are perceived to be useful. If a tool, or interface, is not perceived to be useful then it is often not used, or used ineffectively. As organizations strive to improve communication with and among users by providing more Internet-based collaborative environments, the users' experience in this form of delivery may be tied to a style of user interface look and feel that could negatively affect their overall acceptance and satisfaction of the collaborative environment. The significance of this study is that it applies the technology acceptance model (TAM) as a tool for evaluating style of user interface look and feel in a collaborative environment, and attempts to predict which factors of that model, perceived ease of use and/or perceived usefulness, could lead to better acceptance of collaborative tools within an organization.