Using events to build large scale distributed applications

Author(s):  
Richard Hayton ◽  
Jean Bacon ◽  
John Bates ◽  
Ken Moody
Author(s):  
B. Darsana ◽  
Karabi Konar

Current advances in portable devices, wireless technologies, and distributed systems have created a mobile computing environment that is characterized by a large scale of dynamism. Diversities in network connectivity, platform capability, and resource availability can significantly affect the application performance. Traditional middleware systems are not prepared to offer proper support for addressing the dynamic aspects of mobile systems. Modern distributed applications need a middleware that is capable of adapting to environment changes and that supports the required level of quality of service. This paper represents the experience of several research projects related to next generation middleware systems. We first indicate the major challenges in mobile computing systems and try to identify the main requirements for mobile middleware systems. The different categories of mobile middleware technologies are reviewed and their strength and weakness are analyzed.


Author(s):  
Surya Nepal ◽  
John Zic

In the Service Oriented Architecture (SOA) model, a service is characterized by its exchange of asynchronous messages, and a service contract is a desirable composition of a variety of messages. Though this model is simple, implementing large-scale, cross-organizational distributed applications may be difficult to achieve in general, as there is no guarantee that service composition will be possible because of incompatibilities of Web service contracts. We categorize compatibility issues in Web service contracts into two broad categories: (a) between contracts of different services (which we define as a composability problem), and (b) a service contract and its implementation (which we define as a conformance problem). This chapter examines and addresses these problems, first by identifying and specifying contract compatibility conditions, and second, through the use of compatibility checking tools that enable application developers to perform checks at design time.


Author(s):  
Valentin Cristea ◽  
Ciprian Dobre ◽  
Corina Stratan ◽  
Florin Pop

Security in distributed systems is a combination of confidentiality, integrity and availability of their components. It mainly targets the communication channels between users and/or processes located in different computers, the access control of users / processes to resources and services, and the management of keys, users and user groups. Distributed systems are more vulnerable to security threats due to several characteristics such as their large scale, the distributed nature of the control, and the remote nature of the access. In addition, an increasing number of distributed applications (such as Internet banking) manipulate sensitive information and have special security requirements. After discussing important security concepts in the Background section, this chapter addresses several important problems that are at the aim of current research in the security of large scale distributed systems: security models (which represent the theoretical foundation for solving security problems), access control (more specific the access control in distributed multi-organizational platforms), secure communication (with emphasis on the secure group communication, which is a hot topic in security research today), security management (especially key management for collaborative environments), secure distributed architectures (which are the blueprints for designing and building security systems), and security environments / frameworks.


Author(s):  
Jingmei Yang ◽  
Huoping Chen ◽  
Byoung uk Kim ◽  
Salim Hariri ◽  
Manish Parashar

2011 ◽  
Vol 3 (2) ◽  
pp. 44-58 ◽  
Author(s):  
Meriem Meddeber ◽  
Belabbas Yagoubi

A computational grid is a widespread computing environment that provides huge computational power for large-scale distributed applications. One of the most important issues in such an environment is resource management. Task assignment as a part of resource management has a considerable effect on the grid middleware performance. In grid computing, task execution time is dependent on the machine to which it is assigned, and task precedence constraints are represented by a directed acyclic graph. This paper proposes a hybrid assignment strategy of dependent tasks in Grids which integrate static and dynamic assignment technologies. Grid computing is considered a set of clusters formed by a set of computing elements and a cluster manager. The main objective is to arrive at a method of task assignment that could achieve minimum response time and reduce the transfer cost, inducing by the tasks transfer respecting the dependency constraints.


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