Volume3, Number2, 2002


 

 

Title:

A Parametric Search Strategy for a Quasi-Optimal Joining Position of 3D Potsherds

Author:

Kyoji Hashimura, Shohei Kato and Hidenori Itoh

Abstract:

    In the field of archaeology, reconstruction of earthen-ware imposes a heavy task on archaeologists. In order to reduce their task, we have developed a system that can automatically reconstruct earthenware from given pot-sherds. The system performance is restricted to potsherds shaped in two-dimensional images. This research, thus, aims to develop an enhanced system with three-dimensional techniques. Up to the present, we have pro-posed a framework of the system, and have also devel-oped two essential techniques for the system. The tech-niques, however, enable the system to achieve a simple joint processing was only proposed. Therefore, some gap was caused between two potsherds to be joined. This pa-per defines the functions to evaluate the geometrical pro-portion between two potsherds, and proposes the iterative deepening search algorithm that uses a multi-resolution mesh representation and the function, so as to specify a quasi-optimal joint position of two potsherds. We have implemented the algorithm and have also reported some successful results.

 

 

Title:

Development of a 3D Virtual School with Learning Support Systems

Author:

Satoru Fujii, Jun Iwata, Nobuyuki Okamoto and Tadanori Mizuno

Abstract:

    We have developed Typewriting Training, Mathematics Learning Support and Information Processing Learning Support systems to help students study online. These are additional to the existing “English Learning Support System” called "Web-CALL". We have assessed the effectiveness of these learning support systems by questionnaire. The students who tried them found them very useful. We subsequently constructed a 3D Virtual School in which students can utilize all these learning support systems. The Virtual School comprises the learning support systems within a 3D graphics world written with VRML. The Virtual School has different study rooms linking the learning support systems, and students move freely between the study and learning modules by elevator. We have added interesting activities, moving characters and game scenes to make the modules more attractive. Assessment by student survey showed that the moving characters and activities were interesting and made their study more enjoyable, easier and more interactive.

 

 

Title:

Transactions in software components: Container-interposed transactions

Author:

Marek Procházka and František Plášil

Abstract:

    The paper focuses on transaction context propagation in component-based software architectures, where every component is deployed into a container and client requests may be performed in the scope of a container-interposed transaction. In the existing commercial architectures such as EJB and COM+, the “single attribute approach” is used to specify the transaction context propagation. Being difficult to comprehend, this specification is also not powerful enough to express all the possible transaction propagation policies even for the flat transaction model; advanced transaction models cannot be employed at all. Moreover, the specification takes place as late as at the deployment time so that it is hard to reflect a particular transaction propagation policy in the component code. As a remedy, we propose to specify transaction propagation policy as a part of a component interface by means of a straightforward double attribute (NT&CT) approach. This way, advanced transaction models based on inter-transaction dependencies, giving permissions, and delegation can be also specified.

 

 

Title:

A Constraint-Oriented Design Method for Distributed Cooperative Systems and Efficient Verification Using Symmetries

Author:

Takaaki Umedu, Hirozumi Yamaguchi, Keiichi Yasumoto, Akio Nakata and Teruo Higashino

Abstract:

    In this paper, we propose a design method for distributed cooperative systems (concurrent systems) with symmetries. In the proposed method, we specify distributed cooperative systems in a constraint-oriented model, and verify the deadlock-free property in an efficient manner. In our method, a specification of a system is given as a set of CPNs (coloured Petri-nets) where each CPN is a specification of symmetrical nodes or a constraint for the behavior among different nodes such as temporal ordering of actions. This style allows us to easily modify the behavior of the system by changing the constraints, on the other hand, the system is likely to include deadlocks due to inconsistent constraints. In order to avoid this problem, our method determines some useful sufficient conditions that can reduce the number of states in reachability graphs using symmetries. We have developed a verification tool and had experiments to detect deadlocks in a specification of a network conferencing system in order to show the efficiency of our method.

 

 

Title:

An Integrated Metamodel and its Formal Specification in Z for Component Architecture

Author:

Chee-Yang Song and Doo-Kwon Baik

Abstract:

    Many studies have been conducted on mapping UML and software architecture. Various modeling methods exist as the software architecture model, component model, and object model on the hierarchical level of software development. Unfortunately, these models have problems in usability, understandability, and consistency for designers. It is due to not providing each individual metamodel for each model precisely and an integrated metamodel. Eventually, the mapping relationship among model, component, and object is not clear and systematic. This paper proposes an integrated metamodel for defining the mapping relationship between UML and software architecture. To integrate and specify various methods existing over different design levels, we define each individual metamodel for software architecture model and UML models, then construct an integrated metamodel combined with each metamodel by three layer expressions, and formalize the integrated metamodel using Z. The metamodel is expressed in a class diagram, which represents the syntax and static semantics for target model. Using these metamodels, the designer can understand UML and software architecture from the viewpoint of component architecture more easily, precisely, and consistently, in terms of using the modeling elements specified in our metamodel.

 

 

Title:

Network Monitoring in The Large: Distribution and Integration

Author:

Takeo Saitoh, Glenn Mansfield and Norio Shiratori

Abstract:

    Distributed management is a necessity in today’s growing Internet. Distribution comes with a cost, the overhead and the lack of clarity. Most of the work on distributed management has been done on developing the framework to accommodate the heterogeneity that characterizes the Internet. But little or no work has been done on integrating the distributed information to provide a complete perspective. In this work we show the power of a distributed management system when pieces of distributed information are put in place like pieces of a puzzle. It becomes a powerful tool that provides a deep insight into the operational status of the network. We claim that network configuration information provides the indispensable clue that catalyzes the understanding of the distributed information. We show how the distributed system is used to address various network operation and management problems with particular emphasis on the problem of detecting congestion and locating a congestion bottleneck.

 

 

Title:

Parallel Cost-based Abduction on Heterogeneous Distributed Environments

Author:

Shohei Kato, Hirohisa Seki and Hidenori Itoh

Abstract:

We propose a dynamic load balancing method and an efficient parallel first-order cost-based abductive reason-ing system, which works on heterogeneous distributed environment that consists of several different computa-tional speed workstations. This method grasps the condi-tion of each workstation in a virtual parallel computer, and attempts to keep it uniform. We also implemented a parallel cost-based abductive reasoning system on a vir-tual parallel computer using PVM, and show some ex-perimental results.

 

 

Title:

A Multicast Architecture for Mobile Nodes

Author:

Thomas Noel and Jean-Jacques Pansiot

Abstract:

Group communications are more and more frequently used on the Internet. But until now, they have been considered as an exception, compared to point-to-point communications. The use of mobile hosts is also becoming more and more widespread. We propose a Logical Addressing and Routing architecture (LAR) to deal in a uniform way with point-to-point and multicast communications for mobile or fixed hosts. We compare our architecture to the existing sparse mode multicast protocols and describe how to implement it with IPv6 and its extension headers.