Jinsong Ouyang

Message tracking in SOAP-based Web services

As Web services become more prevalent, the nature of electronic transactions on the Internet changes from simple browser-to-business clicks to an orchestrated flow of messages between cross-enterprise services. Consequently, more than one service could participate in the federated execution of a single transaction. In such cases, the problem of end-to-end management becomes very important. The inherent cross-enterprise or distributed nature of the problem, security of information exchanged, and the complexity in correlating related messages into a single transaction make this problem challenging. We present an approach to track and correlate messages between Web services that are part of a single transaction. We do this by proposing management information exchange agreements between service providers, and a distributed message tracking algorithm that is executed within each service provider. We also explain the techniques for realizing our solution in the case of Web services that communicate using the Simple Object Access Protocol (SOAP).

Evolutionary rule decision using similarity based associative chronic disease patients

Efficient healthcare management has increasingly drawn much attention in healthcare sector along with recent advances in IT convergence technology. Population aging and a shift from an acute to a chronic disease with a long duration of illness have urgently necessitated healthcare service for efficient, systematic health management. Clinical decision support system (CDSS) is an integrated healthcare system that effectively guides health management and promotion, recommendation for regular health check-up, tailor-made diet therapy, health behavior change for self-care, alert service for drug interaction in patients with chronic diseases with a high prevalence. Although CDSS rule-based algorithm aids guidelines and decision making according to a single chronic disease, it is unable to inform unique characteristics of each chronic disease and suggest preventive strategies and guidelines of complex diseases. Therefore, this study proposes evolutionary rule decision making using similarity based associative chronic disease patients to normalize clinical conditions by utilizing information of each patient and recommend guidelines corresponding detailed conditions in CDSS rule-based inference. Decision making guidelines of chronic disease patients could be systematically established according to various environmental conditions using database of patients with different chronic diseases.

Role Based Access Control in Enterprise Application - Security Administration and User Management

One of the most challenging problems in managing large Web-applications is the complexity of security administration and user-profile management. Role based access control (RBAC) has become the predominant model for advanced access control due to the reduced complexity and cost of administration. Under RBAC, security administration is greatly simplified by using roles, hierarchies and privileges, and user management is uncomplicated by using LDAP API specification within the J2EE application. System administrators create roles according to the job functions performed in an organization, grant permissions to those roles, and then assign users to the roles on the basis of their specific job responsibilities and qualifications. We introduce in this paper RBAC in a typical J2EE enterprise application and present architectural details, along with security administration and user-profile management for RBAC. Netegrity SiteMinder provides the RBAC foundation, and J2EE framework serves as the reference model for administration in the application. Then we emphasize the design and implementation of a custom RBAC-model, and the possibilities of optimization of this model

End-to-end transaction management for composite Web based services

Web based services, or e-services are increasingly beginning to cooperate to perform complex tasks. This has resulted in transactions that although begin and end at an e-service have parts of them executed on other cooperating e-services. Because of their federated nature and varied implementation, it is difficult to perform end-to-end management of such transactions that span multiple e-services. The problem would be compounded by the increasing trend of dynamic composition of e-services. Application response measurement is a standard for measuring application responses that originate at a client and involve multiple servers. We extend ARM to the e-services world to perform end-to-end transaction management. In doing so we enable multi-dimensional correlation, a local correlation as well as correlation spanning multiple e-services.

Checkpointing and recovery for distributed shared memory applications

The paper proposes an approach for adding fault tolerance, based on consistent checkpointing, to distributed shared memory applications. Two different mechanisms are presented to efficiently address the issue of message losses due to either site failures or unreliable non-FIFO channels. Both guarantee a correct and efficient recovery from a consistent distributed system state following a failure. A variant of the two-phase commit protocol is employed such that the communication overhead required to take a consistent checkpoint is the same as that of systems using a one-phase commit protocol, while our protocol utilises stable storage more efficiently. A consistent checkpoint is committed when the first phase of the protocol finishes.<<ETX>>

Architecture and implementation of Libra-a library for reliable distributed applications

This paper describes the architecture and implementation of Libra, a library for implementing efficient reliable distributed applications. Libra is designed to provide fault-tolerance transparency and a simple easy to use high-level message passing interface so that the development of reliable distributed applications can be significantly simplified. Fault-tolerance is based on distributed consistent checkpointing and rollback-recovery integrated with a user-level network communication protocol. By employing novel mechanisms, Libra minimises communication overhead for taking a consistent distributed checkpoint and catching messages in transit. With efficient implementation techniques, the prototype of Libra has been implemented on a network of Sun workstations and supports reliable distributed computing at low run-time cost. The simplicity and efficiency of Libra make it a promising approach to construct reliable distributed applications.

A Mechanism of Specifying and Determining Pricing in Utility Computing Environments

Utility services providers offer on-demand services for multiple users and applications from a shared resource pool. The utility computing environment provider manages resources that have multiple dimensions, namely CPU, Memory and Disk. It is important that a mechanism of quantification he utilized for determining pricing. Also in these environments, we believe that price needs to be adapted to reflect and influence dynamic change in demand on resources, and can be used, as an economic mechanism, to efficiently manage a utility computing environment. To achieve this, we propose in this paper an adaptive pricing mechanism. The objective of this scheme is twofold: it, for business objectives, adapts price based upon the supply and demand curves over time intervals; on the other hand, price invisibly manages the distribution of resource demand across time intervals, therefore makes resource utilization more efficient and balanced over time. In this approach, the resource unit to be priced is called capacity unit, and applications are billed based upon the capacity units that have been reserved or used.

eSign: an enterprise portal for secure document management

Many business processes require documents and transactions with trusted signatures. This has been a key issue that blocks enterprises from transforming paper-based business processes into e-business processes. Digital signature and PKI technology make it possible that documents and transactions with the need for signatures can be electronically signed and processed. We describe in this paper the design and implementation of an enterprise portal for secure document management. The portal is a Web-based management system that can be used to, at the enterprise level, streamline document-based business and personal transactions, and securely maintain e-documents in the centralized database. To automate and secure the process of document-based transactions, e.g., filing travel expense reports, the system integrated digital signature and PKI technology for digitally signing and managing documents and forms. Compared to other systems, it is open to various types of user authentication mechanisms, it supports the signing and verification of most document formats, and it provides a Web service endpoint for application integration, aggregation, and automation.

Supporting Cost-Effective Fault Tolerance in Distributed Message-Passing Applications with File Operations

In this paper we present an approach to reliable distributed computing, which incorporates fault tolerance into applications at low cost, in terms of both run-time performance and programming effort required to construct reliable application software. In our model fault tolerance is based on distributed consistent checkpointing and rollback-recovery integrated with a user-level reliable transmission protocol. By employing novel techniques 8and algorithms, our approach is distinguished from other consistent checkpointing schemes by the following features: first, minimum communication overhead for constructing a consistent distributed checkpoint and catching messages in transit during checkpointing; second, tolerance to message losses due to site failures or unreliable non-FIFO networks; and third, efficient checkpointing and recovery of persistent state, i.e., user files. Based on the model, a software library prototype called Libra has been implemented for supporting fault tolerance in distributed message-passing applications with file operations. The library provides an easy to use programming interface including message-passing and file I/O primitives, which hides the complexity of both fault-tolerant network communications and checkpointing and recovering user files from the application level. Experience with a number of long-running distributed applications shows that Libra can provide fault tolerance in a cost-effective manner.

An efficient approach for constructing reliable distributed applications

A trend of supporting fault tolerance in distributed computing systems is to incorporate fault tolerance into applications at low cost, in terms of both run-time performance and programming effort required to construct reliable application software. To meet this objective, we have designed and implemented Libra, a software library running on a network of workstations to support reliable distributed computing efficiently. By providing fault tolerance transparency and a simple, easy to use high-level message-passing interface, Libra simplifies the development of reliable distributed applications. Fault tolerance is based on distributed consistent checkpointing and rollback-recovery integrated with a user-level network communication protocol. To address real-life problems, the library tolerates messages losses, and efficiently supports checkpointing and recovery of user files. Performance evaluations show that Libra imposes low run-time overhead, and minimizes communication overhead for taking a consistent d...