• 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.

• Journal of Educational Research in Mathematics
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• v.13 no.1
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• pp.25-55
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• 2003

In the school mathematics, the negative numbers have been instructed by means of intuitive models(concrete situation models, number line model, colour counter model), inductive-extrapolation approach, and the formal approach using the inverse operation relations. These instructions on the negative numbers have caused students to have the difficulty in understanding especially why the rules of signs hold. It is due to the fact that those models are complicated, inconsistent, and incomplete. So, students usually should memorize the sign rules. In this study we studied on the didactical phenomenology of the negative numbers as a foundational study for the improvement of teaching negative numbers. First, we analysed the formal nature of the negative numbers and the cognitive obstructions which have showed up in the historic-genetic process of them. Second, we investigated what the middle school students know about the negative numbers and their operations, which they have learned according to the current national curriculum. The results showed that the degree they understand the reasons why the sign rules hold was low Third, we instructed the middle school students about the negative number and its operations using the formal approach as Freudenthal suggest ed. And we investigated whether students understand the formal approach or not. And we analysed the validity of the new teaching method of the negative numbers. The results showed that students didn't understand the formal approach well. And finally we discussed the directions for improving the instruction of the negative numbers on the ground of these didactical phenomenological analysis.

• Fashion & Textile Research Journal
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• v.20 no.3
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• pp.304-311
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• 2018

This research used a questionnaire to provide basic data for the design of dressing form that enables the manufacture of senior menswear with an improved fit to match the dissatisfaction with the fit of male suits over the 50s. We used 132 questionnaires as analytical data. The results were: The item 'purchasing method of formal suits' showed that 95.5% purchased ready-to-wear jackets. The 'abdominal obesity type' and 'trunk waist type' had a high frequency of 'complaints about the size of the ready-to-wear jacket'. They choose their suits and wear them directly from the store. It is expected that senior males will complain about ready-to-wear formal suits due to the increase in girth item than normal type due to change of body shape since they consider size to also be important when purchasing suits. The most important part of the body when purchasing suits is the shoulder area, followed by the front width and back width of the fit. As for the degree of recognition of suit size, 38.1% said that they know the size and 'Suit size is hard to understand'. As a result of dissatisfaction with formal dressing, the items of 'Neck wide of get loose', 'Drag line of back neck', 'Not fit of front opening', 'Not fit of shoulder slope' and 'dissatisfaction'. Therefore, it is salient to establish suit fitting system and size system for senior men.

• Journal of KIISE:Software and Applications
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• v.31 no.6
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• pp.750-759
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• 2004

The software of the nuclear power plant digital control system is a safety-critical system where many techniques must be applied to it in order to preserve safety in the whole system. Formal specifications especially allow the system to be clearly and completely specified in the early requirements specification phase therefore making it a trusted method for increasing safety. In this paper, we discuss the NuSCR, which is a qualified formal specification method for specifying nuclear power plant digital control system software requirements. To investigate the application of NuSCR, we introduce the experience of using NuSCR in formally specifying the plant protection system's software requirements, which is presently being developed at KNICS. Case study that shows that the formal specification approach NuSCR is very much qualified and specialized for the nuclear domain is also shown.

• Knowledge Management Research
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• v.11 no.3
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• pp.31-45
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• 2010

IT outsourcing studies have centered on the separate effect of formal contract and relational trust on IT outsourcing performance. In addition, previous studies ignored the importance of the relational capability that combine the formal contract and partnership can be able to deliver IT outsourcing effects. In this paper, we propose an IT governance commitment as a mediated role between relational capability and IT outsourcing performance. We collected data from 143 client companies of IT outsourcing and analyzed it using the PLS method. Our findings are revealed as following: At first, relational capability significantly and directly influence IT governance commitment as well as indirectly through formal contract and partnership. Secondly, IT governance commitment mediate between relational capability and IT outsourcing effect, and in turn affect IT outsourcing performance. The results and implications are further discussed.

• International Journal of Railway
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• v.5 no.2
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• pp.65-70
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• 2012

This paper introduced a novel railway system, Automatic Train Protection and Block (ATPB) briefly, which is proposed to improve the efficiency of existing regional train lines with low cost in Japan. The biggest superiority of ATPB system is a great use of universal and mature technologies, such as GPS and regular mobile telephone networks, so that there is nearly no increment of trackside equipments in the reconstruction. Then in order to guarantee the system safety, a formal model of ATPB is established and analyzed by formal method VDM++. Firstly, the specification is specified by VDM++ formally without ambiguity. Secondly, its internal consistency is proved by discharging the proof obligations. And finally, its satisfiability is checked by systematic testing, which executes specification and checks the outputs against corresponding inputs.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.772-774
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• 2005

안전성이 강조되는 실시간 시스템에서 시스템이 시간의 제약을 만족해야만 한다. 실시간 시스템에서 오류는 잘못된 응답 뿐 만이 아니라 시간적으로 늦은 응답에 대해서도 오류로 분류를 할 수가 있다. 이런 오류들을 모니터하기 위해서 본 논문에서는 커널에 Timed Conformance Monitor를 모듈로 추가하였다. Timed Conformance Monitor를 통해서 실시간 태스크가 시간의 제약을 만족하는지를 분석하고 또한 분석 결과에 따라 오류를 처리할 수 있는 Fault Handler를 추가하여 실시간 시스템에 대한 Fault Tolerance를 보장해 줄 수 있다.

• Journal of The Korean Association of Information Education
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• v.8 no.4
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• pp.555-562
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• 2004

There are informal, semi-formal and formal methods in software specification. Among them, formal method which is based on mathematical theory had been used to remove ambiguity, incompleteness and contradiction efficiently. In this paper, we propose implementation steps from Z specification to EJB source code, Also, as a case study we show steps consisted of specifying stack data structure and implementing it in EJB. In conclusion, Z specification proved to be capable of implementing EJB interface, exception class, method, through refinement and definition of schema, interface, post-condition, pre-condition.

• Journal of the Korea Society of Computer and Information
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• v.8 no.4
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• pp.21-27
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• 2003

In these paper, we define object models in order to represent a correct analysis model, propose translation method to formal specification necessary to uniform and standard. The translated model provide to correctness, consistency and completeness. If it is happen to error in the VDM specification, we can verify model to adapt initial object model step. It increase correctness to retrieval, reduce the costs and efforts of after development because of the verified model used to basic specification in design step.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.939-942
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• 1989

Most of systems are included nonlinear characteristics in practice. One might be faced with difficulties when problems of nonlinear systems are solved. In this paper we present a formal linearization method of nonlinear systems by using the trigonometric Fourier expansion on the state space considering easy inversion. An error bound, an application, and a compensation of this method are also investigated.