• Journal of KIISE:Software and Applications
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• v.35 no.12
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• pp.731-740
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• 2008

A railway control system is one of the typical safety-critical systems. It is required to use formal methods for the requirements specification and verification in order to develop the global-standard railway control systems based on the computer systems. In this paper, we develop a guideline for requirements specification using formal methods, and present a case study of the development of a computer-based railway control system through the application of the proposed guideline. We use the Statechart and the Z method for the formal requirements specifications and verify the consistency and completeness of the formal specifications of the requirements.

• The KIPS Transactions:PartD
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• v.17D no.6
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• pp.431-442
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• 2010

Because embedded system is combined system of hardware and software, we should design by considering elements such as real-time, reactive, small size, low weight, safe, reliable, harsh environment, low cost, and so on. However, those are poorly reflected on current embedded system development. Especially, there is few existed framework-based embedded system development. As a result, there are many internal codes which is not related with system operation in currently developed embedded system, and reusability or variability is not considered into embedded system development. Therefore we propose a formal specification technique using Z language to guarantee completeness or consistency of design of reusability framework proposed for improving reusability of embedded system. Also we assure correctness of framework design by checking Z model through Z-Eves Tool.

• Journal of KIISE:Software and Applications
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• v.31 no.5
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• pp.677-696
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• 2004

Component-based software engineering (CBSE) composes reusable components and develops applications with the components. CBSE is admitted to be a new paradigm that reduces the costs and times to develop software systems. The high quality of component designs can be assured if the consistency and correctness among the elements of a component are verified with formal specifications. Current formal languages for components include only some parts of contracts between interfaces, structural aspects and behavioral aspects of component, component-based system, component composition and variability. Therefore, it is not adequate to use current formal languages in all steps of a component design process. In this paper, we suggest a formal language to specify component designs Component-Z. Component-Z extends Object-Z, adds new notations to specify components. It can be possible to specify interfaces, the inner structure of a component, inner workflows, and workflows among interfaces with Component-Z. In addition, Component-Z provides the notations and semantics to specify variability with variation points, variants and required interfaces. The relation between interfaces and components is defined with mapping schemas. Parallel operator is used to specify component composition. It can be possible to describe deployed components with the specifications of component-based systems. Therefore, the formal specification language proposed in this paper can represent all elements to design components. In the case study, we specify an account management system in a bank so that we show that Component-Z can be used in all steps of component design.

• Journal of KIISE:Software and Applications
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• v.31 no.7
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• pp.883-900
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• 2004

As object-oriented development technology that increases extensibility and reusability has been widely spread, it can shorten development period and enhance quality by reusing verified object-oriented artifacts. Thus we can construct high quality component-based system at short time transforming component-based model using verified object-oriented artifacts. In this paper, we propose techniques to transform available object-oriented design model into component-based model using formal specification techniques in order to increase accuracy of transformation. First, formal specification language for component is defined for formal specification of component-based design. And, techniques for formal specification of object-oriented design using Object-Z, a formal specification language, is proposed in structural, functional, and dynamic aspects. Next, we present techniques for transforming formal specification of object-oriented design into formal specification of component-based design. Through a case study we apply the proposed transformation techniques and show the transformation process of object-oriented formal specification into component-based formal specification.

• BMB Reports
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• v.46 no.4
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• pp.219-224
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• 2013

The cell-fate specification of the anchor cell (AC) and a ventral uterine precursor cell (VU) in Caenorhabditis elegans is initiated by a stochastic interaction between LIN-12/Notch receptor and LAG-2/Delta ligand in two neighboring Z1.ppp and Z4.aaa cells. Both cells express lin-12 and lag-2 before specification, and a small difference in LIN-12 activity leads to the exclusive expressions of lin-12 in VU and lag-2 in the AC, through a feedback mechanism of unknown nature. Here we show that the expression pattern of lag-1/CSL, a transcriptional repressor itself that turns into an activator upon binding of the intracellular domain of Notch, overlaps with that of lin-12. Site-directed mutagenesis of LAG-1 binding sites in lag-1 maintains its expression in the AC, and eliminates it in the VU. Thus, AC/VU cell-fate specification appears to involve direct regulation of lag-1 expression by the LAG-1 protein, activating its transcription in VU cells, but repressing it in the AC.

• The Journal of Korean Association of Computer Education
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• v.3 no.2
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• pp.87-94
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• 2000

Software productivity doesn't satisfy the need of service of software users and software quality isn't improved. Moreover, we still have difficulty in software maintenance. As a plan to counteract solving this crisis, the technology that is called CBSE or Componentware is introduced. Componet Based Software Architecture, one of the technologies associated with CBSE, as a structural description of system, describes both the components composed system of and interaction among these components. Software Architecture provides the technology and the methodology of composition among components in the field of CBSE. is accepted one of core technologies. In this thesis, we analyse information necessary for component specification and then proposed that component specificaton activities using formal specification language Z which is verified with the ability of analysis and logicality. The proposed activities are composed of 9 tasks. By presenting specific 11 products, it is also proposed that component specification activities which is the base of CBSD(ComponentBased Software Development) for reusing.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06b
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• pp.163-166
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• 2011

정형명세 언어인 Z는 상태기반의 명세언어로써 시스템의 기능성을 명세하고 검증하기 좋은 장점을 가지고 있다. 또한 Z에서 제공하는 스키마를 이용하여 복잡한 구조의 상태를 나타내기에 용이하다. 하지만 2개 이상의 시스템으로 구성된 네트워크 상의 통신을 나타내기가 힘든 단점이 있다. 본 논문에서는 Z를 이용하여 네트워크 프로토콜을 명세하기 위한 프레임워크를 제시하고 사례연구를 통해 적용가능성을 살펴본다. 본 연구결과를 토대로 네트워크로 구성된 안전 필수 시스템의 명세 가이드라인을 제시한다.

• Journal of Electrical Engineering and Technology
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• v.4 no.1
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• pp.87-92
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• 2009

Many critical control systems are developed using formal methods. When software applied to such systems is developed, the employment of formal methods in the software requirements specification and verification will provide increased assurance for such applications. Earlier errors of overlooked requirement specification can be detected using the formal specification method. Also, the testing and full verification to examine all reachable states using model checking to undertake formal verification are able to be completed. In this paper, we proposed an eclectic approach to incorporate Z(Zed) formal language and 'Statemate MAGNUM', formal method tools using Statechart. Also we applied the proposed method to train control systems for the formal requirement specification and analyzed the specification results.

• Proceedings of the Korea Multimedia Society Conference
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• 2002.05d
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• pp.661-664
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• 2002

컴포넌트를 개발하는데 있어서 컴포넌트 명세의 정확성과 명세의 검증을 통하여 에러를 찾아 낸다는 것은 컴포넌트의 전체 품질에 매우 중요한 의미를 갖는다. 그러나, 기존의 컴포넌트 명세는 구문적인 측면은 잘 정의하고 있지만, 의미적인 측면은 자연어를 사용하여 모순과 모호성이 흔히 발생한다. 컴포넌트 명세에 있어서 정형적 문법을 사용할 경우 이러한 모호성을 제거함으로써 명세 오류들을 매우 효과적으로 줄여준다. 본 논문에서는 컴포넌트의 품질을 높일 수 있도록 분석력과 논리성이 검증된 정형 명세 언어 Z의 스키마 확장을 이용하여 컴포넌트를 명세하므로써 컴포넌트 구현 및 사용상의 오류를 분석할 수 있는 방법을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04a
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• pp.439-442
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• 2002

컴포넌트 명세는 컴포넌트와 클라이언트 사이의 계약으로 볼 수 있다. 하지만 현재의 컴포넌트 명세는 인터페이스 명세 언어(Interface Definition Language)와 정확성이 결여된 자연어로 작성된 명세에 의존하고 있다. 이러한 명세는 모호성, 불완전성, 모순등을 포함할 수 있다. 따라서 컴포넌트 명세는 이러한 점을 충분히 고려하여 진행되어야 하는데 본 연구에서는 EJB 컴포넌트의 코드 템플릿을 반영하여 요구사항을 Object-Z로 명세하고 이러한 명세로부터 컴포넌트를 구현하는 단계를 제시하였다.