Kinji Mori

Realization of autonomous decentralized computing with the RTO.k object structuring scheme and the HU-DF inter-process-group communication scheme

The autonomy of various subsystems in complex real-time distributed computer systems is a highly desired attribute. Highly autonomous subsystems enable concurrent and largely independent testing/verification and maintenance of the subsystems. In recent years, we formulated two system structuring techniques which could be used as fundamental tools for enhancing the subsystem autonomy: the RTO.k object structuring scheme and the HU-DF inter-process-group communication scheme. Three approaches of using the above two tools for enhancement of the three different basic types of autonomy in an object: relocation autonomy; service timing autonomy; and data acceptance autonomy, are presented.<<ETX>>

Autonomous decentralized community communication for information dissemination

To meet the increasing demand for real-time content delivery, the proposed autonomous decentralized community communication system offers an efficient information dissemination infrastructure with a decentralized architecture. ADCCs aim is to help end-user communities communicate and exchange information efficiently; to meet this goal, the system uses an application-level multicast technique that arbitrarily scales to large groups. The ADCC system also features a scalable community construction and maintenance scheme that eases the burden of organizing an online community network.

Autonomous decentralized database system for assurance in heterogeneous e-business

Due to the advancement in the Information Technology, different kind of companies with heterogeneous needs have had the necessity to cooperate among them to get more benefit in a continuous changing market. That is heterogeneous e-business. In order to cope with such kind of e-business, a platform which can effectively realize heterogeneous needs, real time, flexibility and fault-tolerance is needed. This paper focuses on the database field that is indispensable for the e-business. Thus, it proposes Autonomous Decentralized Database System, which is composed of two techniques. In the first one, the concept of Allowable Volume (AV) is introduced, while in the second one, a Mobile Agent (MA) that adjusts the AV of each site is shown. Since the MA is always moving among the sites, and each site can always negotiate AV with the MA autonomously, the system can realize assurance. Furthermore, the effectiveness of the proposed system is shown by simulation.

Autonomous decentralized systems technologies and their application to train transport operation system

Large, mission-critical systems are required to satisfy, as nearly as possible, a 100% availability requirement. This imposes an on-line property, which includes on-line expansion for constructing a system step-by-step without stopping the systems operation, on-line maintenance for testing and repairing during the system operation, and fault-tolerance. Autonomous Decentralized Systems (ADS) have been proposed for achieving the on-line property, and its technologies have been effectively applied in various fields including transportation, factory automation, information service and so on. ADS are realized by the Data Field (DF) architecture, where data is broadcast with the content code corresponding to the data attached. Each subsystem selects its data depending on the content code instead of the address. Subsystems independently start their execution after all of the necessary data is received. Based on the DF architecture, the on-line property is realized. One of the applications of the ADS for the Toyko Metropolitan-Area Train Transport Operation Control System is discussed here to show that the on-line property and the heterogeneous requirements for real-time control and high-throughput information services are achieved.

Trend of autonomous decentralized systems

Markets and the technologies have been rapidly changing and advancing. User requirements have been diversified and unpredictable. Under these evolving situations, an autonomous decentralized system (ADS) was proposed for resolving the on-line property to achieve step-by-step expansion, maintenance/test and fault-propagation prevention without stopping the entire system. Research and development has been accelerated in the world not only for control systems but also for wide-area information systems. In China, ADS activities are especially promoted in railway systems. Here as examples, a railway ground-control system and a train on-board-control system, where each of the railway stations and trains has autonomy to regulate the trains through coordinating mutually, are shown to be electively operated.

Atomicity of transaction processing in heterogeneous autonomous decentralized system

The requirements to integrate the heterogeneous applications are newly emerging. When integrating heterogeneous systems, it is necessary not to violate their respective characteristics, and also the complex works should be reduced. The recursive model on the basis of ADS concept has been proposed for the integration, where the attached system is regarded as one autonomous subsystem for the other. When a transaction is processed among the heterogeneous systems, it is better for the transaction to be guaranteed from the different points of view. The atomicity for the transaction processing under this model is categorized to the three levels that is, the Global Atomic Action, the Semi-global Atomic Action and the Local Atomic Action. The integration of the heterogeneous systems is evaluated through the assurance level which is measured how much the transaction processing is additionally improved by the integration. The realization and design techniques for their atomic actions are proposed and the effectiveness of these techniques is demonstrated by the simulation, in which the tradeoff between the assurance level and the response time is balanced.

Autonomous data synchronization in heterogeneous systems to assure the transaction

Many companies have been forced to quickly respond to changing user needs. To provide more convenient services to consumers, the cooperation within a company or across companies have been requested. As a result, the heterogeneous information systems are also requested to be integrated together. By utilizing the heterogeneity among systems and by cooperating between systems, it becomes possible to draw out new values from them without violating each systems characteristic. In the heterogeneous systems, such as the data generation timings or frequencies are different, the data synchronization itself should be done by each system without relying on the single coordinator, because the system configurations are always changing, and members of application group which use synchronous data combination are also changing. In this paper we propose the autonomous data synchronization technique in the heterogeneous systems. The application objects which requires the synchronous combination of the data in each system can locally judge which combination of data is most adequate as the synchronous combination by comparing the synchronous information with others. Thus all systems can use the consistent combination as the synchronous data only by collecting the data locally and exchanging the synchronous information. In addition, the cost of synchronization in each system, which is measured by the synchronization waiting time (SWT) and backward data utilization (BDU) becomes even. As this proposed method is not relying on the single coordinator, it works correctly even if the system configuration is dynamically changed, or even if members of SyncApps are changed. The simulation results show the cost fairness when three systems are interconnected in straight line.

Multi-layered Data Consistency Technology, An Enhanced Autonomous Decentralized Data Consistency Technology for IC Card Ticket System

The vulnerability discovery process for a program describes the rate at which the security vulnerabilities are discovered. Being able to predict the vulnerability discovery process allows developers to adequately plan for resource allocation needed to develop patches for them. It also enables the users to assess the security risks. Thus there is a need to develop a model of the discovery process that can predict the number of vulnerabilities that are likely to be discovered in a given time frame. Recent studies have produced vulnerability discovery process models that are suitable for a specific version of a software. However, these models may not accurately estimate the vulnerability discovery rates for a software when we consider successive versions, hi this paper, we propose a new approach for quantitatively modeling the vulnerability discovery process, based on shared source code measurements among multi-version software systems. Such a modeling approach can be used for assessing security risk both before and after the release of a version. The applicability of the approach is examined using two open source software systems, viz., Apache HTTP Web server and Mysql DataBase Management System (DBMS). We have examined the relationship between shared code size and shared vulnerabilities between two successive versions. We observe that vulnerabilities continue to be discovered for an older version because part of its code is shared by the newer and more popular later version. Thus, even when the installed base of an older version has declined, vulnerabilities applicable to it are still discovered. Our results are validated using the source code and vulnerability data for two major versions of Apache HTTP Web server and two major versions of Mysql DBMS.

Layered Memory Architecture for High IO Intensive Information Services to Achieve Timeliness

Storage systems need to provide high IO transactions in addition to their capacity and availability requirements to achieve high assurance characteristics, such as fault tolerance and timeliness. Caches built in large and medium size storage systems have not been very effective to improve the IO transactions and overall performance of the system. Caches at various layers of the memory hierarchy in computing systems are more fast but very small compared to the adjacent lower level of storage device. This paper proposes a novel concept to exploit local memory as a block device to improve the IO performance of storage systems called data transmission system (DTS) concept. This concept is based on hierarchical layered memory utilization and management in the information system. Data accessed frequently is maintained on the managed DTS cache device in close proximity to the CPU. The proposed concept is substantially different from the conventional unmanaged cache in the computing systems. System architecture and detailed system design are presented in this paper to realize the proposed concept. Performance evaluation of the system has been carried out through numerical as well as application scenario. The experimental results show improvement of the order of 10 to 100 times faster IO transactions and reduce CPU wait time significantly.

Autonomous Decentralized System and Its Strategic Approach for Research and Development

Autonomous Decentralized System (ADS) has been making progress in these 31 years since it was proposed in 1977. During these long years in the rapidly advancing computer and communication technologies, the ADS concept has not been changed but its technologies have been growing in accordance with the change and diversity of the social, economical and personal requirements and through the globalization of the market and the restructuring organizations. The ADS technologies are systematized to cover all processes of system design, operation, maintenance and modification. This paper reviews the work done in fields of ADS in past 31 years from not only technological perspectives, but it also encompasses users requirements and value, system design, industrial activity, academic activity and standardization [1]–[26]. Moreover the new directions of the ADS are suggested.