Kazutoshi Yokoyama

A differential-analysis approach for improving SOAP processing performance

The performance of SOAP is lower than that of existing distributed object technologies such as RMI and CORBA, because SOAP needs extra process parsing and building message to process an XML document. Therefore, performance improvement for SOAP processing is challenge to apply SOAP to a high-performance system. In the case that we focus on SOAP message features, we notice a SOAP message format is pre-defined for each service program and the format does not change while the system is running. A little part of a SOAP message is variable and the rest that includes tag description is invariable. In this paper, we focus on the above features and we create a template from a SOAP message format. Our approach parses a SOAP message by analyzing differential between a SOAP message and the template. Our approach improves the performance to improve lexical analysis and validation while processing an XML document.

A method for composing process of nondeterministic Web services

Web services have been common technologies for providing services over the Internet. In the future, it is expected that a usage model that autonomously integrates services will become ordinary in, for example, B2B integration. However, such method of executing pre-defined process lacks flexibility because a service requestor must know in advance the interface of all integrated services. Accordingly, there is a need for a method that composes a process from the requestors requirement independent of the interface of services. This paper proposes the architecture and a method for composing a process automatically. Our approach is formulating Web services function and a requestors requirement as the transitions of his state by means of situation calculus and calculating what process is matched with the requirement. In our method, we model message-oriented execution of service. Moreover, our method is capable of composing not just a sequential process but also a process including conditional choices. Therefore, our method has the basic feature to be able to compose nondeterministic Web service.

Controlling CPU Usage for Processes with Execution Resource for Mitigating CPU DoS Attack

In a ubiquitous environment, the hardware resources are limited; thus, an appropriate resource management mechanism is required for guaranteeing its processing activity. However, most operating systems (OSs) lack an access control mechanism for CPU resources to guarantee satisfactory processing and to safeguard the system from malicious attacks that affect the CPU resources, resulting in denial of service (DoS). Access control is not intended for general OSs and CPU resources, which are important for the execution of a program. As a result, OSs cannot control the usage ratio of CPU resources. In this paper, we propose an access control model for CPU resources based on an execution resource. The proposed model can control the usage ratio of CPU resources appropriately for each program domain. This execution resource can be applied to mitigate DoS attacks.

A precise estimation technique for test coverage of components in object-oriented frameworks

In general, a component-based system uses only a part of the functions of its software components. Therefore, precise structural testing for components requires to specify what functions of the components are used in the system. In addition, in the case with an object-oriented component, some existing studies point out that testing of all possible bindings between a call site and the methods that the site may invoke is extremely ineffective. In this paper, we propose a method for precisely estimating test coverage of components on an object-oriented framework by using its deployment descriptor and evaluate its effectiveness.

Design and overhead estimation of device driver process

Conventional operating systems used to have device drivers as kernel modules or embedded objects. Therefore, maturity of a device driver influences on the reliability of the entire system. There is a method for constructing device driver as an user process for improving the reliability. Device driver process enhances the reliability of the operating system. However, device driver process has large overhead. In this paper, we propose a method for constructing device drivers process and evaluating these overhead. Also, this paper shows that the overhead of device driver process can be estimated.

Requirements for open service collaboration among Web services

Development of Internet technology in recent years has changed not only system integration technologies but also business styles. The technology of present e-services and e-business enables collaboration of services or enterprise systems through the Internet, and to realize new value-added services and complex enterprise systems. The development of XML technology in particular enables open and dynamic collaboration of individual services. This paper presents the requirements for open service collaboration among Web services. In open and dynamic service collaboration, we think it is important to perform business transactions safely. We propose functionality of service brokerage based on credit records and functionality to guarantee business transactions between services.