Nien-Lin Hsueh

A quantitative approach for evaluating the quality of design patterns

In recent years, the influence of design patterns on software quality has attracted an increasing attention in the area of software engineering, as design patterns encapsulate valuable knowledge to resolve design problems, and more importantly to improve design quality. As the paradigm continues to increase in popularity, a systematic and objective approach to verify the design of a pattern is increasingly important. The intent session in a design pattern indicates the problem the design pattern wants to resolve, and the solution session describes the structural model for the problem. When the problem in the intent is a quality problem, the structure model should provide a solution to improve the relevant quality. In this work we provide an approach, based on object-oriented quality model, to validate if a design pattern is well-designed, i.e., it answers the question of the proposed structural model really resolves the quality problems described in the intent. We propose a validation approach to help pattern developers check if a design pattern is well-designed. In addition, a quantitative method is proposed to measure the effectiveness of the quality improvement of a design pattern that pattern users can determine which design patterns are applicable to meet their functional and quality requirements.

A Model-Driven Multicore Software Development Environment for Embedded System

Multi-core programming is no more a luxury; it is now a necessity, because even embedded processors are becoming multi-core. However, the state-of-the-art techniques such as OpenMP and the Intel Threading Building Block (TBB) library are far from user-friendly due to the tedious work needed in explicitly designing multi-core programs and debugging. At the present days, a solution for above problems will be that to enhance the abstract level of multicore embedded software design. By leveraging on the expertise gained from Verifiable Embedded Real-Time Application Framework (VERTAF), we propose a Multi-Core version of VERTAF, called VERTAF/ Multi-core (VMC in short). VMC is an integrated development environment for multi-core embedded software architecture. Developers would be able to 1. describe their system requirements with SysML by using this environment, 2. model their design with SysML standard notation, 3. automatically apply a pattern structure into their design for a high quality multicore embedded system, 4. generate source code through a well-designed model; 5. map to different hardware architecture as assigned by the model, and 6. finally we can test the code.Using the model driven architecture (MDA) design flow in SysML, we saw a significantly improvement on productivity and quality of a multicore embedded programming over traditional approach.

An Approach of Quality of Service Assurance for Enterprise Cloud Computing (QoSAECC)

Enterprise Cloud Computing (ECC) is a new trend for IT service provisioning due to the concerns of cost down and increase of Quality of Service (QoS). However, there are many obstacles to the services moving from traditional enterprise computing to cloud environment, such as how to assure the quality of services, security, data availability, data privacy, etc. In order to support the risk free migration of IT provisioning for enterprises from traditional enterprise architecture to cloud computing, an integrated solution is urgently needed. In this paper, we propose a formal model, to assist not only the ECC services design and construction through SaaS, PaaS, IaaS, but also the simultaneous monitoring and dynamic analysis on the QoS factors for the promises from QoS service providers, such as security, performance, timeliness, throughput, reliability, and the service level agreements (SLAs) for multiple ECC consumers. Based on the formal model, analysis model and testing model can be generated consequently to support automatic testing as well as run time monitoring to assure the satisfaction to the requirements/SLAs constraints.

An automatic smart shopping cart deployment framework based on pattern design

An automatic embedded software generation framework that can create and evolve Zigbee applications is proposed. The framework consists of two major modules, pattern extraction and code generation. Pattern extraction and development are designed to provide Zigbee application with model reuse and modification. SysML serves as a medium between pattern development and code generation. State diagrams, class diagrams and sequence diagram help describes a specific application scenario. A smart shopping cart application has been implemented using this pattern based software framework. The current location of a shopping cart has been monitored constantly by the WSN network through a signature sensing technique implemented by our lab. Both the electronic map on the server console and the PXA255 on board embedded system find a shortest path from the current location to the target product location assigned by user on the LCD screen. This evidence proves the success of the framework process. This software framework allows user to store the whole smart shopping application scenario in the design pattern repository. Further extension of this pattern can be exercised for creating other Zigbee applications such as patient localization in a hospital environment, item retrieval in large scale storage ware house, and green power energy saving applications etc.

XML-Based Reusable Component Repository for Embedded Software

In the development stage of the embedded system, the market demand and system development trend will be influence by the Time to Market. Reliable and fast system deployment is not easy to implement. Reduced price and system development time can increase the product value. Thus the component re-use library can help reduce the development time, this kind of design can reduce the emergence of rewriting and raise the efficiency by a wide margin. We design and study the reusable component in this research, proposing a prototype database based on XML. This technique has many advantages like reduces the time required for storage, improves the overall efficiency of the system, shortens the development time, increases reliability and reduces the risks handling etc.

Supporting Design Enhancement by Pattern-Based Transformation

In general, a design pattern is usually documented in the form of an essay, with descriptions and rough design such as intent, motivation, structure, behavior, applicability and consequence, etc. Even though there are tools supporting pattern application, developers still may misuse patterns since misunderstanding. It may result failures of systems because of inconsistencies or design errors. In fact, the refinement process by applying a design pattern is merely the addition or removal of model elements in structure view. The refinement process for each design pattern is almost constant whenever the same pattern is applied. In this paper, we propose an approach for design pattern application and assisting the design enhancement by model transformation. Furthermore, we demonstrate our approach by a case study on a real-world multi-core embedded system PVE (Parallel Video Encoder), where a design pattern Command Pipeline is designed for the design enhancement.

Adaptive Performance Monitoring for Embedded Multicore Systems

With the advent of multicore processors, the performance of software has been elevated to new unforeseen heights via parallelization. However, this has not been achieved without new problems cropping up due to parallelization. One serious issue is the performance bottleneck due to cache misses or resource starvation, which is hard to detect in application software especially when the software has dynamically changing behavior. Performance monitors are usually employed for such purposes. Nevertheless, monitors have introduced their own computation and communication overheads, especially in embedded multicore systems. In this work, we try to estimate the effects of monitor overheads on different types of applications, such as CPU-bound and IO-bound tasks. Further, we give suggestions on the number and type of monitors to use for such embedded multicore applications. Besides trying to reduce monitor overheads, we also aim for the accuracy and the immediacy of the monitored information. Through a real-world example, namely digital video recording system, we demonstrate how different monitoring periods affect the tradeoff between accuracy and immediacy of the monitored information.

Supporting Tool for Embedded Software Testing

Embedded software testing is a complex and difficult task. During the testing process, testing tasks often require additional hardware devices to assist. This paper, in the perspective of software solution, presents a supporting tool for testing embedded software. This tool can automatically generate test cases and test drivers, and supports unit test and coverage test which are based cross testing technology and multiple rounds mechanism. The test results can be visually represented to facilitate the observation. By using our constructed testing environment in the embedded platform to do testing experiments, the experiment results show that our constructed testing environment is workable.

A case study of pattern-based software framework to improve the quality of software development

In recent years, development of the software industry and demand for software systems have increased rapidly, but developers often does not know whose suggestion to follow regarding methodologies of software engineering. One reason for that is the difficulty in applying new software engineering technologies. Developers take a long time to train. Another reason is the difficulty in integrating CASE toolsets. So many indeterminate factors make the development process more and more complex. On the other hand, software development is too customized, and software reuse is difficult. The reasons above are the cause for software development and maintenance to become more complex and difficult to control. In this paper we explore the importation of a software pattern-based framework, and the development of an ERP/support chain system. Based on software patterns, developers can separate development and business so as to reduce problems caused by the developers lack of business experience. The quality of the product can thus be enhanced, software development costs be reduced, and software maintenance be improved.

Trade-off Requirement Engineering

A major challenge in requirements engineering of knowledge-based systems is that the requirements to be captured are imprecise in nature and usually conflicting with each other [25,37,48]. Balzer et al. have argued that informality is an inevitable (and ultimately desirable) feature of the specification process [2]. Similar ideas are also advocated by other researchers such as Borgida [5], Feather [16]‚ Fickas [12], Waters [36], Niskier [33] and their colleagues. Borgida et al. have further elaborated that a good requirement modeling approach should take the problem of describing nature kinds into account, which usually runs the risk of being vague and subject to contradiction [5].