While horizontal partitioning of traditional relational databases is well studied, there is in comparison very little in the literature about the partitioning of NoSQL databases, especially those that are cloud based, such as Amazon's SimpleDB. In order to optimize the response time of a web application using a cloud based database, it is possible to partition the database for storage on local regional servers. In this work, data mining and cluster analysis of database logs is used in order to partition, thus essentially caching, data on local servers. This work compares the average response times of three partitioning algorithms on a simple web application using a cloud based NoSQL database management system. The experimental study shows that the techniques presented can improve web application performance.

E-commerce web sites typically have large fluctuations in their IT resource usage, while rapid elasticity is an essential characteristic of cloud computing. These characteristics make the cloud a good fit for hosting e-commerce web sites. Cloud providers deploy their cloud in their data centers. However, cloud providers usually have a limited number of data center locations around the world. Thus, e-commerce web sites in the cloud may be far away from their customers. Long client-perceived response latency may cause e-commerce web sites to lose business. To solve this problem, we propose a virtual proxy solution to reduce the response latency of the e-commerce site in the cloud. In our approach, a virtual proxy platform is designed to cache applications and data of e-commerce sites. A k-means based table partitioning algorithm is designed to select frequently used data from the database in the cloud. We have used an industrial e-commerce benchmark TPC-W to evaluate the performance of our approach. The experimental results show that our approach can significantly reduce the client-perceived response time.

The ACM's “Computer Science Curriculum 2008: An Interim Revision of CS 2001” suggests 31 core hours of Software Engineering covering the standard phases of software development. At many universities, including ours, Software Engineering is a capstone course with a semester-long team project. While the course covers the software development lifecycle there is not enough time in a single semester for students to gain an appreciation for all phases, especially the importance of testing and documentation to the maintenance phase which is the longest phase in successful software projects. To address this, a new course, Software Maintenance and Testing, was added as a pre-requisite to Software Engineering. The course will be implemented in fall, 2011. Students will be surveyed to determine if their appreciation for different development models, documentation, recording of design decisions, and clean code are improved by maintaining code prior to developing a brand-new or greenfield project. A Likert scale instrument will be develop to evaluate students' attitudes. The research instrument will be tuned until validity and reliability are achieved. Preliminary and baseline results will be presented.

Information brings economic value to the customers and data is the "soul" of the enterprise. Data centers are playing more and more important roles in the enterprises. Storage technology is one of the fundamental technologies behind data centers. The storage knowledge and skills are needed for data center professionals. Thus, we have developed a new course, Storage Administration, for Computer Information Technology (CIT) major students at Northern Kentucky University (NKU). Since our CIT program emphasizes hands-on learning, we have developed the course based on hands-on laboratory components. The laboratory components are developed based on open source software and simulator software. In this paper, we describe the hands-on laboratory components in details.

This paper presents a cloud based content adaptation system for mobile learners. Mobile agents are developed to perform content adaptation and they can migrate among hosts in the cloud. Also, a weighted link graph approach is proposed to discover students' access patterns. Weight values are used to arrange layout of links on a Web page to reduce mobile learners' clicking and scrolling efforts.

Cloud computing has aroused wide research interests and has been accepted by industry. Services are playing the essential role in cloud computing as cloud computing refers to “both the applications delivered as services over the Internet and the hardware and systems software in the datacenters that provide those services”. Therefore, service-oriented architecture should play an important role in cloud computing. In addition, one of the characteristics of cloud computing is to make services available on demand. Given a group of services, different demands may involve different set of services and in different order. This is related to services reuse and composition. However, existing methods only solve service composition in a binary manner: Either a solution exists or no solutions at all. In this paper, we propose the concept of virtual services, which physically do not exist, but are conceptually treated in the same way as physical services. Virtual services are useful when traditional service compositions fail. Virtual services can connect the existing physical services and enable the composition process to succeed. The specifications of virtual services will provide valuable information about how to develop real services to meet the requirements of the given demand. In this paper, we present algorithms that can help identify the virtual services in the case of composition failure and provide the specification of virtual services for further analysis and development.

Cloud computing is an emerging computation paradigm. To support successful cloud computing, service oriented architecture (SOA) should play a major role. Due to the nature of widely distributed service providers in clouds, the service performance could be impacted when the network traffic is congested. This can be a major barrier for tasks with real-time requirements. In clouds, this problem can be solved by migrating services to different platforms such that the communication cost can be minimized. In this paper, we consider the problem of service selection and migration in clouds. We develop a framework to facilitate service migration and design a cost model and the decision algorithm to determine the tradeoffs on service selection and migration.

Edge server replication is an effective solution to achieve high performance in dynamic web applications, such as Web services. Many Web services involve frequent accesses to large-scale backend databases. Current database replication techniques are not directly applicable to edge server architectures. There is no algorithm to dynamically and automatically select the tables for replication. Also, most of the solutions do not consider the potentially limited disk sizes at the edge servers and the needs for them to serve many application sites. In this paper, we present a novel weighted table graph based database replication approach for edge servers to address these problems. Every step in our approach is based on quantitative computation, so it can generate an accurate result. Experimental studies show that our database replication approach significantly improves the performance of Web systems in terms of client response latency, Web application server off loading, and network bandwidth saving.

Edge server replication is an effective solution to achieve high performance in dynamic Web applications, such as Web services. It can replicate the application logic and the data close to the clients to reduce the response latency and network traffic and to offload the servers. Many Web services involve frequent accesses to large-scale backend databases. Current database replication techniques are not directly applicable to edge server architectures. Most of the solutions do not consider the potentially limited disk sizes at the edge servers and the needs for them to serve many application sites. In this paper, we present a novel database replication approach, PSO-MP, for edge servers to address the problems. Experimental studies show that the PSO-MP approach significantly improves the performance of Web systems in terms of client response latency, Web application server offloading, and network bandwidth saving.

Content adaptation is an important technique for mobile devices. Existing content adaptation systems have been developed with specific adaptation goals. In this paper, we present an extensible content adaptation system, Xadaptor. We take a rule-based approach to facilitate extensible, systematic, and adaptive content adaptation. It integrates adaptation mechanisms for various content types and organizes them into the rule base. Rules are invoked based on the individual client information. We classify HTML page objects into structure, content, and pointer objects. Existing content adaptation techniques mainly focus on content objects and do not consider adaptation for structure and pointer objects. In Xadaptor, novel adaptation techniques for the structure object HTML table have been developed. We use fuzzy logic to model the adaptation quality and guide the adaptation decision. To demonstrate the feasibility of our approach, we have implemented a prototype system. Experimental studies show that Xadaptor is capable of on-the-fly content adaptation and is easily extensible

Conventional admission control models incur some performance penalty. First, admission control computation can overload a server that is already heavily loaded. Also, in large-scale media systems with geographically distributed server clusters, performing admission control on each cluster can result in long response latency, if the client request is denied at one site and has to be forwarded to another site. Furthermore, in prefix caching, initial frames cached at the proxy are delivered to the client before the admission decisions are made. If the media server is heavily loaded and, finally, has to deny the client request, forwarding a large number of initial frames is a waste of critical network resources. In this paper, a novel distributed admission control model is presented. We make use of proxy servers to perform the admission control tasks. Each proxy hosts an agent to coordinate the effort. Agents reserve media server's disk bandwidth and make admission decisions autonomously based on the allocated disk bandwidth. We develop an effective game theoretic framework to achieve fairness in the bandwidth allocation among the agents. To improve the overall bandwidth utilization, we also consider an aggressive admission control policy where each agent may admit more requests than its allocated bandwidth allows. The distributed admission control approach provides the solution to the stated problems incurred in conventional admission control models. Experimental studies show that our algorithms significantly reduce the response latency and the media server load.

Many agent-based systems have been developed over the past decade; however, the security issues are usually not addressed adequately. In order to make the mobile agent paradigm more useful and acceptable for Web and Internet applications, the security considerations should go beyond the protection of basic agent execution environments. In this paper, we present the design of a robust Java-based mobile agent system, PeAgent. The PeAgent system not only incorporates a fine-grain agent privilege control mechanism, but also includes a multi-level protection mechanism that can be used throughout the life-cycle of agents. A two-level domain hierarchy is constructed to organize the large number of Internet nodes in the agent system into manageable units: the global/domain management unit (GMU/DMU). Each unit consists of a certification authority (CA) and a location manager (LM). The certificates issued from GMU and DMU define the access privileges on the PeAgent servers for each agent. A context hierarchy is built up on the PeAgent servers for fine-level resource access control and agent management. Overall, the PeAgent system provides a secure computing environment for widely distributed applications over a network of heterogeneous platforms. It also facilitates the development of secure Web-based applications.