• Title/Summary/Keyword: Formal Methods

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PLC Real Time OS Verification & Validation in Formal Methods (정형기법을 이용한 PLC RTOS 검증)

  • Choi, Chang-Ho;Song, Seung-Hwan;Yun, Dong-Hwa;Hwang, Sung-Jae
    • Proceedings of the KIEE Conference
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    • 2005.07d
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    • pp.2489-2491
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    • 2005
  • Currently, Programmable Logic Contorller(PLC) uses Real Time Operation System(RTOS) as basic OS. RTOS executes defined results as to defined time. General features of RTOS emphasize the priority in each task, high-speed process of external interrupt, task scheduling, synchronization in task, the limitation of memory capacity. For safety critical placement, PLC software needs Verification and Validation(V&V). For example, nuclear power plant. In this paper, PLC RTOS is verified by formal methods. Particularly, formal method V&V uses verification tool called 'STATEMATE', and shows the results.

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Formal Specification for Secure Functions (보안기능 정형화 설계방법 연구)

  • Yoo, Hee-Jun;Choi, Jin-Young;Kim, Woo-Gon
    • Proceedings of the Korea Information Processing Society Conference
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    • 2000.04a
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    • pp.349-355
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    • 2000
  • 본 논문에서는 정형 명세 언어 Z를 이용하여 사용자 인증에 사용되어지는 MD5 Message Digest 알고리즘을 정형 명세 방법론에 따라서 명세 한 경험을 기술한다. 인터넷 기술의 발달로 인하여 통신상에서의 전자 상거래가 활성화되면서 서비스를 이용하는 사용자들에 대한 사용자 정보 보안과 보안 시스템에 접근하는 사용자에 대한 사용자 인증에 관한 문제가 매우 중요하게 부상되고 있다. 이 문제를 해결하기 위해서 보안에 관련된 많은 암호화 기법과 알고리즘이 개발되고 있고, 전세계적으로 이런 알고리즘으로 구현된 보안 시스템의 등급을 나누고 있다. 이런 보안 등급에서 일반적으로 정형기법을 사용하여 구현된 보안 상품이 최상의 평가를 받고 있다. 하지만, 국내에서는 이러한 분야에 대한 연구가 전무한 상태여서 어떠한 기준을 적용하는 것이 좋은 지를 판단하기가 매우 어려운 실정이다. 따라서, 본 논문에서는 이러한 문제에 대한 연구로 정형 명세 언어를 이용해서 인증 알고리즘을 명세하고 검토하는 작업을 수행한 경험을 기술한다.

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ForTIA : A Tool Supporting Formal Method based on LOTOS (ForTIA: LOTOS 기반의 정형기법 지원도구)

  • Cho, Soo-Sun;Cheon, Yoon-Sik;Oh, Young-Bae;Chung, Yun-Dae
    • Journal of KIISE:Computing Practices and Letters
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    • v.6 no.2
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    • pp.161-172
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    • 2000
  • In this paper, we introduce the development of a LOTOS-based tool, supporting formal methods, called ForTIA (A Formalism for Telecommunication and Information Systems). By using LOTOS, an ISO standard formal specification language, the user requirements and system models can be abstracted and represented formally. Therefore, the system can be validated and verified on the specifications, before implementations. ForTIA supports light-weight formal methods based on validation to be used in real industry. Key functions of ForTIA are simulation and C++ code generation. In simulation, tree based visual validation mechanism is provided and in code generation, the full C++ source code is generated to be used for system implementations.

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A Study on the Models Corresponding to Interior Image Types (실내이미지 유형별 모델 개발에 관한 연구)

  • 방희조;박영순
    • Proceedings of the Korean Institute of Interior Design Conference
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    • 1999.04a
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    • pp.94-97
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    • 1999
  • The purpose of this study was to prepare the visual communication tool, which would be used for the interior design consulation to reduce the communication gap between an interior designer and a client. To achieve the study purpose, review of literature, questionnaire survey, qualitative analysis and design research methods were used. The major results of this study were as follows: 1) "Image Cube" was designed as a comprehensive rule to classify interior image types. By this, eight interior image types were classified: SFU(Simple-Formal-Urbane), SFN(Simple-Formal-Natural), SCU(Simple-Casual-Urbane), SCN(Simple-Casual-Natural), DFU(Decorative-Formal-Urbane), DFN(Decorative-Formal-Natural), DCU(Decorative-Casual-Urbane), DCN(Decorative-Casual-Natural). 2) The Interior image collages were composed to present the overall feeling of each interior image type. 3) The Interior image models which would be used as the standard to be modified to various sub-types through the interior design consultation were produced corresponding to interior image types.age types.

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Formal Analysis of Automatic Train Protection and Block System for Regional Line Using VDM++

  • Xie, Guo;Hei, Xinhong;Mochizuki, Hiroshi;Takahashi, Sei;Nakamura, Hideo
    • 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.

Clinical Characteristics of Formal Thought Disorder in Schizophrenia (조현병에서 형식적 사고장애의 임상적 특성)

  • Yang, Chaeyoung;Kim, Han-sung;Kim, Eunkyung;Kim, Il Bin;Park, Seon-Cheol;Choi, Joonho
    • Korean Journal of Biological Psychiatry
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    • v.28 no.2
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    • pp.70-77
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    • 2021
  • Objectives Our study aimed to present the distinctive correlates of formal thought disorder in patients with schizophrenia, using the Clinical Language Disorder Rating Scale (CLANG). Methods We compared clinical characteristics between schizophrenia patients with (n = 84) and without (n = 82) formal thought disorder. Psychometric scales including the CLANG, the Brief Psychiatric Rating Scale (BPRS), the Young Mania Rating Scale (YMRS), the Calgery Depression Scale for Schizophrenia (CDSS) and the Word Fluency Test (WFT) were used. Results After adjusting the effects of age, sex and total scores on the BPRS, YMRS and WFT, the subjects with disorganized speech presented significantly higher score on the abnormal syntax (p = 0.009), lack of semantic association (p = 0.005), discourse failure (p < 0.0001), pragmatics disorder (p = 0.001), dysarthria (p < 0.0001), and paraphasic error (p = 0.005) items than those without formal thought disorder. With defining the mentioned item scores as covariates, binary logistic regression model predicted that discourse failure (adjusted odds ratio [aOR] = 5.88, p < 0.0001) and pragmatics disorder (aOR = 2.17, p = 0.04) were distinctive correlates of formal thought disorder in patients with schizophrenia. Conclusions This study conducted Clinician Rated Dimensions of Psychosis Symptom Severity (CRDPSS) and CLANG scales on 166 hospitalized schizophrenia patients to explore the sub-items of the CLANG scale independently related to formal thought disorders in schizophrenia patients. Discourse failure and pragmatics disorder might be used as the distinctive indexes for formal thought disorder in patients with schizophrenia.

Visual Representation of Temporal Properties in Formal Specification and Analysis using a Spatial Process Algebra (공간 프로세스 대수를 이용한 정형 명세와 분석에서의 시간속성의 시각화)

  • On, Jin-Ho;Choi, Jung-Rhan;Lee, Moon-Kun
    • The KIPS Transactions:PartD
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    • v.16D no.3
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    • pp.339-352
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    • 2009
  • There are a number of formal methods for distributed real-time systems in ubiquitous computing to analyze and verify the behavioral, temporal and the spatial properties of the systems. However most of the methods reveal structural and fundamental limitations of complexity due to mixture of spatial and behavioral representations. Further temporal specification makes the complexity more complicate. In order to overcome the limitations, this paper presents a new formal method, called Timed Calculus of Abstract Real-Time Distribution, Mobility and Interaction(t-CARDMI). t-CARDMI separates spatial representation from behavioral representation to simplify the complexity. Further temporal specification is permitted only in the behavioral representation to make the complexity less complicate. The distinctive features of the temporal properties in t-CARDMI include waiting time, execution time, deadline, timeout action, periodic action, etc. both in movement and interaction behaviors. For analysis and verification of spatial and temporal properties of the systems in specification, t-CARDMI presents Timed Action Graph (TAG), where the spatial and temporal properties are visually represented in a two-dimensional diagram with the pictorial distribution of movements and interactions. t-CARDMI can be considered to be one of the most innovative formal methods in distributed real-time systems in ubiquitous computing to specify, analyze and verify the spatial, behavioral and the temporal properties of the systems very efficiently and effectively. The paper presents the formal syntax and semantics of t-CARDMI with a tool, called SAVE, for a ubiquitous healthcare application.

A Study on the Pattern Grading for Men's Formal Wear (남성정장 상.하의 그레이딩에 관한 연구)

  • 백경자;유경진;이정란
    • Journal of the Korean Society of Clothing and Textiles
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    • v.26 no.6
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    • pp.843-852
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    • 2002
  • The purpose of this study was to propose a computer-based grading method for men's formal wear according to the sizing systems based on the size and dimension whereby manufactured men's formal wear can be classified. The following procedures were as follows : 1) We surveyed the sizing systems and the computer-grading methods that have been used and presently practiced by the domestic garment industry of the ready-made men's wear. 2) Using the survey data of the domestic men's ready-made clothing industry and that of the National Anthropometric Survey of Korea in 1997, we proposed the new sizing and grading systems of men's formal wear within the framework of the Korean Garment Industry's directions and the data of the domestic men's ready-made clothing industry. 3) The suitability of the new grading systems to the domestic garment industry were put to a wearing teat. The findings were as follows : 1) Survey of the domestic ready-made garment industry showed that each company classified its own manufactured goods according to its own sizing and grading systems. 2) The superiority of the grading system was been demonstrated by a high approval rate of the subjects who participated in the testing.

The Study on the Korean Plastic Consciousness of the Contemporary Interior Space in Korea (한국의 현대 실내공간에 나타난 한국적 조형의식에 관한 연구)

  • 오인욱
    • Korean Institute of Interior Design Journal
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    • v.13 no.5
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    • pp.74-81
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    • 2004
  • The three basic elements of human life -clothing, food and shelter- had been evolved through different periods and cultural realms, as their spatial applications show distinct characteristics that are manifested through sensibilities only inherent to its specific culture. Especially in the interior spaces, possibilities to approach them in three-dimensional aspects allow formal characteristics to be expressed that are distinct to the country. Formal sensibilities embedded in interior space In Korea also follows such pattern, developed through various contemporary interpretations of Korean traditional formal sensibilities, including harmony with nature, simplicity, lightness, real and fake, and principle of harmony are being redefined by spatially expressed in contemporary language. That is, traditional formal sensibilitiesare filtered through various application methods such as composition, negotiation and modification, accommodating spatial manifestations to be not simply preserved nor replicated, but rather reconstructed through metaphor, symbol, abstraction and contrast. From this perspective, the Korean traditional formal sensibilitiesis not a notion fixed in the past, but a distinct perspectives evolving throughout periods of time that are constantly reconsidered and reinterpreted in our interior space. By examining Korean sensibilities manifested in interior space in the both diachronic aspects of tradition vs. contemporary, as well as synchronic aspects among various disciplines simultaneously, we would be able to generate a linkage to the dichotomous categories of tradition and contemporary.

Formal Validation Method and Tools for French Computerized Railway Interlocking Systems

  • Antoni, Marc
    • International Journal of Railway
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    • v.2 no.3
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    • pp.99-106
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    • 2009
  • Checks and tests before putting safety facilities into service as well as the results of these tests are essential, time consuming and may show great variations between each other. Economic constraints and the increasing complexity associated with the development of computerized tools tend to limit the capacity of the classic approval process (manual or automatic). A reduction of the validation cover rate could result in practice. This is not compatible with the French national plan to renew the interlocking systems of the national network. The method and the tool presented in this paper makes it possible to formally validate new computerized systems or evolutions of existing French interlocking systems with real-time functional interpreted Petri nets. The aim of our project is to provide SNCF with a method for the formal validation of French interlocking systems. A formal proof method by assertion, which is applicable to industrial automation equipment such as interlocking systems, and which covers equally the specification and its real software implementation, is presented in this paper. With the proposed method we completely verify that the system follows all safety properties at all times and does not show superfluous conditions: it replaces all the indoor checks (not the outdoor checks). The advantages expected are a significant reduction of testing time and of the related costs, an increase of the test coverage rate, an answer to the new demand of railway infrastructure maintenance engineering to modify and validate computerized interlocking systems. Formal methods mastery by infrastructure engineers are surely a key to prove that more safety is not necessarily more expensive.

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