Performance measurements of Web services

Web services are rapidly evolving application-integration technologies that allow applications in heterogeneous environments to communicate with each other. In this thesis we perform a measurements-based study of an e-commerce application that uses web services to execute business operations. We use the TPC-W specification to generate a session-based workload. The component level response times and the hardware resource usage on the different machines are measured. The component level response times are extracted from the application server logs. From the results it is seen that as the workload increases the response times of the web services components increase. From the hardware resource usage it is clear that web service components require more processing time due to the processing of XML data required in each web service call. The method used in this thesis allows us to study the impact that different components can have on the overall performance of an application

Measurements based performance analysis of Web services

Web services are increasingly used to enable interoperability and flexible integration of software systems. In this thesis we focus on measurement-based performance analysis of an e-commerce application which uses Web services components to execute business operations. In our experiments we use a session-oriented workload generated by a tool developed accordingly to TPC-W specification. The empirical results are obtained for two different user profiles, Browsing and Ordering, under different workload intensities. In addition to variation in workloads we also study the applications performance when Web services are implemented using .NET and J2EE. Unlike the previous work which was focused on the overall server response time and throughput, we present Web interaction, software architecture, and hardware resource level analysis of the system performance. In particular, we propose a method for extracting component level response times from the application server logs and study the impact of Web services and other components on the server performance. The results show that the response times of Web services components increase significantly under higher workload intensities when compared to other components. (Abstract shortened by UMI.)

A standards-based ICT framework to enable a service-oriented approach to clinical decision support

This research provides evidence that standards based Clinical Decision Support (CDS) at the point of care is an essential ingredient of electronic healthcare service delivery. A Service Oriented Architecture (SOA) based solution is explored, that serves as a task management system to coordinate complex distributed and disparate IT systems, processes and resources (human and computer) to provide standards based CDS. This research offers a solution to the challenges in implementing computerised CDS such as integration with heterogeneous legacy systems. Reuse of components and services to reduce costs and save time. The benefits of a sharable CDS service that can be reused by different healthcare practitioners to provide collaborative patient care is demonstrated. This solution provides orchestration among different services by extracting data from sources like patient databases, clinical knowledge bases and evidence-based clinical guidelines (CGs) in order to facilitate multiple CDS requests coming from different healthcare settings. This architecture aims to aid users at different levels of Healthcare Delivery Organizations (HCOs) to maintain a CDS repository, along with monitoring and managing services, thus enabling transparency. The research employs the Design Science research methodology (DSRM) combined with The Open Group Architecture Framework (TOGAF), an open source group initiative for Enterprise Architecture Framework (EAF). DSRM’s iterative capability addresses the rapidly evolving nature of workflows in healthcare. This SOA based solution uses standards-based open source technologies and platforms, the latest healthcare standards by HL7 and OMG, Decision Support Service (DSS) and Retrieve, Update Locate Service (RLUS) standard. Combining business process management (BPM) technologies, business rules with SOA ensures the HCO’s capability to manage its processes. This architectural solution is evaluated by successfully implementing evidence based CGs at the point of care in areas such as; a) Diagnostics (Chronic Obstructive Disease), b) Urgent Referral (Lung Cancer), c) Genome testing and integration with CDS in screening (Lynch’s syndrome). In addition to medical care, the CDS solution can benefit organizational processes for collaborative care delivery by connecting patients, physicians and other associated members. This framework facilitates integration of different types of CDS ideal for the different healthcare processes, enabling sharable CDS capabilities within and across organizations

Software performance engineering of a web service-based clinical decision support infrastructure

This paper has two contributions: a) it proposes a web services-based infrastructure to support Clinical Decision Support Systems (CDSSs) for processing multi-domain medical data from the obstetrical, perinatal and neonatal care domains, and b) applies Software Performance Engineering (SPE) to the proposed infrastructure. This extends a XML-based framework for medical data interoperability and integration of CDSSs into the Neonatal Intensive Care Unit, developed previously by the authors. The framework integrates CDSSs, such as Artificial Neural Networks (ANNs), Case-Based Reasoning (CBR) tools, and alert detection systems. The goal is to reduce medical errors, to support the physician's decision-making process and to improve ultimately patient care. We applied SPE from the early design stages in order to ensure that the system will meet its performance requirements, and to identify possible solutions for relieving the performance limitations of this prototype system. The performance evaluation is based on a layered queuing network model of the proposed web services-based infrastructure

Software Perfomance Assessment at Architectural Level: A Methodology and its Application

Las arquitecturas software son una valiosa herramienta para la evaluación de las propiedades cualitativas y cuantitativas de los sistemas en sus primeras fases de desarrollo. Conseguir el diseño adecuado es crítico para asegurar la bondad de dichas propiedades. Tomar decisiones tempranas equivocadas puede implicar considerables y costosos cambios en un futuro. Dichas decisiones afectarían a muchas propiedades del sistema, tales como su rendimiento, seguridad, fiabilidad o facilidad de mantenimiento. Desde el punto de vista del rendimiento software, la ingeniería del rendimiento del software (SPE) es una disciplina de investigación madura y comúnmente aceptada que propone una evaluación basada en modelos en las primeras fases del ciclo de vida de desarrollo software. Un problema en este campo de investigación es que las metodologías hasta ahora propuestas no ofrecen una interpretación de los resultados obtenidos durante el análisis del rendimiento, ni utilizan dichos resultados para proponer alternativas para la mejora de la propia arquitectura software. Hasta la fecha, esta interpretación y mejora requiere de la experiencia y pericia de los ingenieros software, en especial de expertos en ingeniería de prestaciones. Además, a pesar del gran número de propuestas para evaluar el rendimiento de sistemas software, muy pocos de estos estudios teóricos son posteriormente aplicados a sistemas software reales. El objetivo de esta tesis es presentar una metodología para el asesoramiento de decisiones arquitecturales para la mejora, desde el punto de vista de las prestaciones, de las sistemas software. La metodología hace uso del Lenguaje Unificado de Modelado (UML) para representar las arquitecturas software y de métodos formales, concretamente redes de Petri, como modelo de prestaciones. El asesoramiento, basado en patrones y antipatrones, intenta detectar los principales problemas que afectan a las prestaciones del sistema y propone posibles mejoras para mejoras dichas prestaciones. Como primer paso, estudiamos y analizamos los resultados del rendimiento de diferentes estilos arquitectónicos. A continuación, sistematizamos los conocimientos previamente obtenidos para proponer una metodología y comprobamos su aplicabilidad asesorando un caso de estudio real, una arquitectura de interoperabilidad para adaptar interfaces a personas con discapacidad conforme a sus capacidades y preferencias. Finalmente, se presenta una herramienta para la evaluación del rendimiento como un producto derivado del propio ciclo de vida software

Securely sharing dynamic medical information in e-health

This thesis has introduced an infrastructure to share dynamic medical data between mixed health care providers in a secure way, which could benefit the health care system as a whole. The study results of the universally data sharing into a varied patient information system prototypes