In this diploma thesis we have aimed to identify metrics that accommodate two chosen system quality factors and implementing the selected metrics in a metrics tool. The metrics chosen should measure change in the system quality factors reusability and maintainability for the middleware system COS at Telenor Mobile and similar systems. The metrics tool should support the aspect-oriented programming language AspectJ, and is planned to be a plugin to the open source code analysis framework XRadar. Changes due to introduction of aspects are of particular interest. We have through a GQM process identified the following subcharacteristics for the chosen system quality factors: modularity, testability, analyzability, changeability and stability. Questions are formulated to analyze these sub factors, and metrics that can answer the questions are chosen. We have implemented the tool AspectMetrics, which calculate metrics on Java and AspectJ code and generates an XML report containing the measurement results. A transformation from XML to HTML web pages is also provided. The metrics tool can measure size metrics, like the number of statements and the number of classes, coupling, fan-in/fan-out, cohesion and advice-in/advice-out. Advice-in and advice-out are two new metrics which respectively measures how many advice a class (or aspect) is affected by and how many joinpoints an advice hits on. These metrics are inspired by the concept for the fan-in and fan-out metrics. The tool has been used to analyze two versions of the system DIAS v.2.0, which is a part of a diploma study in 2000. We have in our preparation project in 2003 added aspects to the DIAS system while keeping the system functionally equal to the original version. We have used our metrics tool to calculate the differences between the system with and the system without aspects. The introduction of aspects gave a positive change in coupling, fan-in/fan-out and size measures, while cohesion was negatively affected. The metrics thus, overall, indicated a positive change to the subcharacteristics testability, analyzability, changeability and stability and both the main quality factors. There was no indication of a positive change to modularity. The analysis of the measurement results indicates that most of the metrics perform as intended. The size metrics, coupling, fan-in/fan-out, and advice-in/advice-out all gave results that corresponded to what we had expected. However, the cohesion measure did not behave in a way that could be correlated to the actual changes performed on the code. A closer analysis showed that moving and merging of functionality could result in either an increase or a decrease in cohesion. Thus we find that cohesion, at least in its current form, is not a suitable metric when using aspect-oriented programming. Further, this gave reason to reinvestigate the disappointing modularity results. With a reworked set of criteria we also found indication of improved modularity.

As broadband connections to the Internet become more common, new information sharing applications that provide rich services to distributed users will emerge. Furthermore, as computing devices become pervasive and better connected, the scalability requirements for Internet-based services are also increasing. Distributed object middleware has been widely used to develop such applications since it made it easier to rapidly develop distributed applications for heterogeneous computing and communication systems. As the application's scale increases, however, the client/server architecture limits the performance due to the bottleneck at the centralized servers. The recent development in peer-to-peer technologies creates a new opportunity for addressing scalability and performance problems for services that are used by many nodes. In a peer-to-peer system, peer nodes can contribute a fraction of their resources to the system, enabling more flexible and extended sharing between the entities in the system. When peer nodes are required to contribute their resources by replicating a service for self and others, however, several new challenges arise. Our thesis is that non-dedicated resources in a distributed system can be utilized to replicate shared objects dynamically so that the quality and scalability of a distributed service can be achieved with lower cost by replicating the objects at right places and updates to those shared objects can be disseminated efficiently and quickly. The following are the contributions of our work that has been done to validate the thesis. 1. A new fair and self-managing replication algorithm that allows distributed non-dedicated resources to be used to improve service performance with lower cost. 2. A multicast grouping algorithm that is used to disseminate updates to the shared objects among a large set of heterogeneous peer nodes to keep consistent view for all peer nodes. It groups nodes with similar interests into same group and multicasts all the required data to the group so that the unwanted data received by each node can be minimized. 3. An overlay construction algorithm that aims at reducing both network latency and total network traffic when delivering data through the built overlay network. 4. An implementation of a distributed object framework, GT-RMI, that allows peer nodes to invoke dynamically replicated objects transparently. The framework can be configured for a particular peer node through a policy file.

Thesis (M.S. in computer science)--Washington State University, December 2009. / Title from PDF title page (viewed on Feb. 9, 2010). "School of Electrical Engineering and Computer Science." Includes bibliographical references (p. 92-94).

Mobile devices are the dominant interface for interacting with online services as well as an efficient platform for cloud data consumption. Cloud computing allows the delivery of applications/functionalities as services over the internet and provides the software/hardware infrastructure to host these services in a scalable manner. In mobile cloud computing, the apps running on the mobile device use cloud hosted services to overcome resource constraints of the host device. This approach allows mobile devices to outsource the resource-consuming tasks. Furthermore, as the number of devices owned by a single user increases, there is the growing demand for cross-platform application deployment to ensure a consistent user experience. However, the mobile devices communicate through unstable wireless networks, to access the data and services hosted in the cloud. The major challenges that mobile clients face when accessing services hosted in the cloud, are network latency and synchronization of data. To address the above mentioned challenges, this research proposed an architecture which introduced a policy-based middleware that supports user to access cloud hosted digital assets and services via an application across multiple mobile devices in a seamless manner. The major contribution of this thesis is identifying different information, used to configure the behavior of the middleware towards reliable and consistent communication among mobile clients and the cloud hosted services. Finally, the advantages of the using policy-based middleware architecture are illustrated by experiments conducted on a proof-of-concept prototype.

Ubiquitous computing (ubicomp) is a compelling vision for how people will interact with multiple computer systems in the course of their daily lives. To date, practitioners have created a variety of infrastructures, middleware and toolkits to provide the flexibility, ease of programming and the necessary coordination of distributed software and hardware components in physical spaces. However, to-date no one approach has been adopted as a default or de-facto standard. Consequently the field risks losing momentum as fragmentation occurs. In particular, the goal of ubiquitous deployments may stall as groups deploy and trial incompatible point solutions in specific locations. In their defense, researchers in the field argue that it is too early to standardize and that room is needed to explore specialized domain-specific solutions. In the absence of an agreed upon set of standards, we argue that the community must consider a methodology that allows systems to evolve and specialize, while at the same time allowing the development of portable applications and integrated deployments that work between between sites. To address this we studied the programming models of many commercial and research ubicomp systems. Through this survey we gained an understanding of the shared abstractions required in a core programming model suitable for both application portability and systems integration. Based on this study we designed an extensible core model called the Ubicomp Common Model (UCM) to describe a representative sample of ubiquitous systems to date. The UCM is instantiated in a flexible and extensible platform called the Ubicomp Integration Framework (UIF) to adapt ubicomp systems to this model. Through application development and integration experience with a composite campus environment, we provide strong evidence that this model is adequate for application development and that the complexity of developing adapters to several representative systems is not onerous. The performance overhead introduced by introducing the centralized UIF between applications and an integrated system is reasonable. Through careful analysis and the use of well understood approaches to integration, this thesis demonstrates the value of our methodology that directly leverages the significant contributions of past research in our quest for ubicomp application and systems interoperability.

No description available.

Ubiquitous computing (ubicomp) is a compelling vision for how people will interact with multiple computer systems in the course of their daily lives. To date, practitioners have created a variety of infrastructures, middleware and toolkits to provide the flexibility, ease of programming and the necessary coordination of distributed software and hardware components in physical spaces. However, to-date no one approach has been adopted as a default or de-facto standard. Consequently the field risks losing momentum as fragmentation occurs. In particular, the goal of ubiquitous deployments may stall as groups deploy and trial incompatible point solutions in specific locations. In their defense, researchers in the field argue that it is too early to standardize and that room is needed to explore specialized domain-specific solutions. In the absence of an agreed upon set of standards, we argue that the community must consider a methodology that allows systems to evolve and specialize, while at the same time allowing the development of portable applications and integrated deployments that work between between sites. To address this we studied the programming models of many commercial and research ubicomp systems. Through this survey we gained an understanding of the shared abstractions required in a core programming model suitable for both application portability and systems integration. Based on this study we designed an extensible core model called the Ubicomp Common Model (UCM) to describe a representative sample of ubiquitous systems to date. The UCM is instantiated in a flexible and extensible platform called the Ubicomp Integration Framework (UIF) to adapt ubicomp systems to this model. Through application development and integration experience with a composite campus environment, we provide strong evidence that this model is adequate for application development and that the complexity of developing adapters to several representative systems is not onerous. The performance overhead introduced by introducing the centralized UIF between applications and an integrated system is reasonable. Through careful analysis and the use of well understood approaches to integration, this thesis demonstrates the value of our methodology that directly leverages the significant contributions of past research in our quest for ubicomp application and systems interoperability.

Zugl.: Darmstadt, Techn. Univ., Diss.

Thesis (Ph.D) - Swinburne University of Technology, Faculty of Information & Communication Technologies, Centre for Information Technology Research, 2007. / A thesis to CITR - Centre for Information Technology Research, Faculty of Information and Communication Technologies, Swinburne University of Technology, for the degree of Doctor of Philosophy, 2007. Typescript. Bibliography p. 145-160.

Stuttgart, Univ., Fachstudie, 2006.