Yoshiaki Fukazawa

A metrics suite for measuring reusability of software components

In component-based software development, it is necessary to measure the reusability of components in order to realize the reuse of components effectively. There are some product metrics for measuring the reusability of object-oriented software. However, in application development with reuse, it is difficult to use conventional metrics because the source codes of components cannot be obtained, and these metrics require analysis of source codes. We propose a metrics suite for measuring the reusability of such black-box components based on limited information that can be obtained from the outside of components without any source codes. We define five metrics for measuring a components understandability, adaptability, and portability, with confidence intervals that were set by statistical analysis of a number of JavaBeans components. Moreover, we provide a reusability metric by combining these metrics based on a reusability model. As a result of evaluation experiments, it is found that our metrics can effectively identify black-box components with high reusability.

Model driven development for rapid prototyping and optimization of wireless sensor network applications

In order to develop Wireless Sensor Network (WSN) applications, it is necessary to develop prototypes in a low-cost way and to optimize application performance. Existing development approaches enable to develop a low-cost prototype by concealing the detail of WSN from the developers. However, there is a trade-off between the development cost of prototype and the description capability needed to optimize the application performance. We propose a Model-Driven Development (MDD) process to enable a low-cost prototyping and detailed optimization. To enable such a development process, we define modeling languages, which describe an application at three abstraction levels, and transformation rules, which transform models described by our modeling language to concrete one. Using our process, in prototyping, the developer describes a model by using the modeling language at the highest abstraction level and automatically obtains an executable model by using transformation rules. In addition, in optimizing, the developer can automatically obtain the models at more concrete abstraction level than the prototype by using transformation rules and modifies them in greater detail by using each modeling language.

Classifying security patterns

Patterns combine experience and good practices to develop basic models that can be used for new designs. Security patterns join the extensive knowledge accumulated about security with the structure provided by patterns to provide guidelines for secure system design and evaluation. In addition to their value for new system design, security patterns are useful to evaluate existing systems. They are also useful to compare security standards and to verify that products comply with some standard. A variety of security patterns has been developed for the construction of secure systems and catalogs of them are appearing. However, catalogs of patterns are not enough because the designer does not know when and where to apply them, especially in a large complex system. We discuss here several ways to classify patterns. We show a way to use these classifications through pattern diagrams where a designer can navigate to perform her pattern selection.

Pheromone model: application to traffic congestion prediction

Social insects perform complex tasks without top-down style control, by sensing and depositing chemical markers called “pheromone”. We have examined applications of this pheromone paradigm towards intelligent transportation systems (ITS). Many of the current traffic management approaches require central processing with the usual risk for overload, bottlenecks and delays. Our work points towards a more decentralized approach that may overcome those risks. In this paper, a car is regarded as a social insect that deposits (electronic) pheromone on the road network. The pheromone represents density of traffic. We propose a method to predict traffic congestion of the immediate future through a pheromone mechanism without resorting to the use of a traffic control center. We evaluate our method using a simulation based on real-world traffic data and the results indicate applicability to prediction of immediate future traffic congestion. Furthermore, we describe the relationship between pheromone parameters and accuracy of prediction.

A Generalized Software Reliability Model Considering Uncertainty and Dynamics in Development

Development environments have changed drastically in recent years. The development periods are shorter than ever and the number of team has increased. These changes have led to difficulties in controlling the development activities and predicting the end of developments. In order to assess recent software developments, we propose a generalized software reliability model based on a stochastic process, and simulate developments that include uncertainties and dynamics, such as unpredictable requirements changes, shortening of the development period, and decrease in the number of members. We also compare our simulation results to those of other software reliability models. Using the values of uncertainties and dynamics obtained from our model, we can evaluate the developments in a quantitative manner.

Software product line evolution method based on kaizen approach

Continuing optimal product line development needs to evolve core assets in response to market, technology or organization changes. In this paper, we propose a product line evolution method based on the kaizen approach. Kaizen is a continuous improvement method that is adopted in Japanese industry. The important points of the kaizen are to prepare a work standard and continue to improve processes by correcting the differences between the standard and actual results. Our core asset kaizen method provides a standard that includes core asset types based on simple metrics, kaizen patterns representing expertise, and kaizen processes for continuous improvement.

A Coupling-based Complexity Metric for Remote Component-based Software Systems Toward Maintainability Estimation

Remote-component-based software systems (CBS) must provide high maintainability to support operation over long periods of time and correspond to changes in enterprise requirements/environments. Measurements of the degree of complexity of a system are one technique for evaluating maintainability. However, conventional complexity metrics are unable to reflect the overall complexity of the system, because they do not incorporate a procedure to account for characteristics of CBS. To help maintenance work proceed smoothly, we propose a new metric that measures the coupling-based complexity of CBS by abstracting the target systems structure through a step-wise process and taking into consideration the characteristics of remote components. Our metric can be applied to CBS based on the Enterprise JavaBeans component architecture. As a result of experimental evaluations, it is found that our metric better reflects the maintainability than conventional metrics. It is also found that our metric is nonredundant with existing metrics such as coupling factor.

Model-Driven-Development-Based Stepwise Software Development Process for Wireless Sensor Networks

To meet future demands for wireless sensor network (WSN) software, both experts and average software developers should be involved in WSN software development. However, WSN software development is difficult for the average software developer because data processing-related design and network-related design are tangled in the software. Here, we propose a software development process for WSN software by stepwise refinement. Our process enables stepwise refinement to separately address data processing-related and network-related concerns, reuse of well-defined designs, and implementations for network-related concerns prepared by the experts, and perform model-driven development to obtain source codes from models by model transformations. Additionally, we used case studies using actual WSN software development and user studies to evaluate how our proposed process can support actual WSN software development.

Recovering traceability links between requirements and source code in the same series of software products

If traceability links between requirements and source code are not clarified when conducting maintenance and enhancements for the same series of software products, engineers cannot immediately find the correction location in the source code for requirement changes. However, manually recovering links in a large group of products requires significant costs and some links may be overlooked. Here, we propose a semi-automatic method to recover traceability links between requirements and source code in the same series of large software products. In order to support differences in representation between requirements and source code, we recover links by using the configuration management log as an intermediary. We refine the links by classifying requirements and code elements in terms of whether they are common or specific to the products. As a result of applying our method to real products that have 60KLOC, we have recovered valid traceability links within a reasonable amount of time. Automatic parts have taken 13 minutes 36 seconds, and non-automatic parts have taken about 3 hours, with a recall of 76.2% and a precision of 94.1%. Moreover, we recovered some links that were unknown to engineers. By recovering traceability links, software reusability will be improved, and software product line introduction will be facilitated.

Model-Driven Security Patterns Application Based on Dependences among Patterns

The spread of open-software services through the Internet increases the importance of security. A security pattern is one of the techniques in which developers utilize security experts’ knowledge. Security patterns contain typical solutions about security problems. However there is a possibility that developers may apply security patterns in inappropriate ways due to a lack of consideration on dependencies among patterns. Application techniques of security patterns that consider such dependencies have not been proposed yet. In this paper, we propose an automated application technique of security patterns in model driven software development by defining applications procedures of security patterns to models as model transformation rules with consideration for pattern dependencies. Our technique prevents inappropriate applications such as the application of security patterns to wrong model elements and that in wrong orders. Therefore our technique supports developers apply security patterns to their own models automatically in appropriate ways.