• Proceedings of the Korean Nuclear Society Conference
• /
• 1997.05a
• /
• pp.153-158
• /
• 1997

This paper describes a formal safety analysis technique which is demonstrated by performing empirical formal safety analysis with the case study of beamline hutch door Interlock system that is developed by using PLC(Programmable Logic Controller) systems at the Pohang Accelerator Laboratory. In order to perform formal safety analysis, we have built the Z formal specifications representation from user requirement written in ambiguous natural language and target PLC ladder logic, respectively. We have also studied the effective method to express typical PLC timer component by using specific Z formal notation which is supported by temporal history. We present a formal proof technique specifying and verifying that the hazardous states are not introduced into ladder logic in the PLC-based safety critical system.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.20 no.3
• /
• pp.481-492
• /
• 1996

The purposes of the present study were (1) to examine the differences between the experienced group in buying foreign-brand formal wear and the non-experienced group in terms of demographic characteristics, clothing expenditures, and purchase behaviors of formal wear, and (2) to investigate the purchase behaviors of and the extent of post-purchase satisfaction to foreign-brand formal wears for purchase group of foreign-brand formal wear. By using questionnaire consisting of 20 questions, data were collected from 754 female consumers in age range of 20~59. Chi-square analysis and t-test were used for data analysis. Significant differences were found between the groups in educational levels, monthly clothing expenditures, monthly household income, the number of formal wear purchased per season, store patronage, items often purchased, perceived proper price per item, and criteria for selecting stores and evaluating products. The group with experiences in purchasing foreign-brand formal wear showed high satisfaction levels with the quality of foreign-brand formal wears. When buying foreign-brand formal wears, the experienced group considered styles and color as important evaluative criteria, and favored stores having sales with wide assortmetsn.

• Korean Journal of Mathematics
• /
• v.22 no.1
• /
• pp.169-180
• /
• 2014

In this study, we consider the informal and formal definition of limit on the basis of middle and high school curriculum, and then analyze the reason of difficulties experienced when sophomores learn the formal definition(${\epsilon}-{\delta}$ procedure) of limit. We conducted teaching of the formal definition of limit with sophomores and analyzed their errors which were appeared when they applied to limits problems. In addition, we try to improve the understanding of ${\epsilon}-{\delta}$ procedure of the limit taught in analysis.

• Journal of Information Processing Systems
• /
• v.11 no.2
• /
• pp.184-204
• /
• 2015

Fuzzy Formal Concept Analysis (FCA) is a mathematical tool for the effective representation of imprecise and vague knowledge. However, with a large number of formal concepts from a fuzzy context, the task of knowledge representation becomes complex. Hence, knowledge reduction is an important issue in FCA with a fuzzy setting. The purpose of this current study is to address this issue by proposing a method that computes the corresponding crisp order for the fuzzy relation in a given fuzzy formal context. The obtained formal context using the proposed method provides a fewer number of concepts when compared to original fuzzy context. The resultant lattice structure is a reduced form of its corresponding fuzzy concept lattice and preserves the specialized and generalized concepts, as well as stability. This study also shows a step-by-step demonstration of the proposed method and its application.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.17 no.3
• /
• pp.79-99
• /
• 1992

The DEVS (Discrete Event system Specification) formal model for discrete event simulation is a hierarchical, modular model. Because the DEVS formal model has a mathematical structure, it provides a theoretic background of discrete event simulation model. However, the DEVS formal model is difficult to understand because of its mathematical structure. Also, since the DEVS formal model is often constructed by heuristic, subjective method of model designer from the model, a systematic model built-in methodology does not exist. In this paper, we propose the model formalization methodology from an informal model to the DEVS formal model. For this formalization methodology, we introduce formal tools for model construction based on the DEVS ( from an informal model : Event Dependency Graph (EDG) for the event analysis and State Representation Graph(SRG) for the system state analysis.

• Journal of the Korean Society of Mechanical Technology
• /
• v.13 no.2
• /
• pp.21-29
• /
• 2011

This paper examines the applicability of formal safety assessment to the passenger ships. This is followed by an analysis of passenger ship characteristics and a proposed formal safety assessment methodology. Five interlocking steps are described to construct a safety model including novel risk assessment, cost-benefit analysis and decision-making approaches. A case study is carried out in order to demonstrate the proposed methodology. Further development in formal safety assessment in the context of passenger ship safety is finally discussed in detail.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.26 no.5
• /
• pp.675-683
• /
• 2002

The purposes of the study were to analyze the changes in formal attires and decorative features of middle age Korean women during the last half of 20th century and to find out any significant differences in formal attires according to periods. The study was a documentary research, and data were collected from 344 family wedding photographs by convenient sampling. The statistics used were content analysis, frequency and a time series analysis, and the results were as follows : 1. Four schematic clusters of formal attires were categorized according to skirt(chima) length and width, jacket(jogori) length, motifs and decorative features; simple classic, decorative classic, fashionable, and extravagant fashionable. Simple classic attires were popular until 1960s, the decorative classics were appeared from late 1960s to 1970s, fashionable attires were introduced from the late 1970s and the attires became more luxurious and extravagant until 2000. 2. Color symbolism in couples mothers'attires according to the couples gender - pink or red for the bride's mother and blue or green for groom's mother - was introduced from the late 1970s, and reached the maximum level by the early 1980s but slowly disappeared after the late 1980s. 3. The complete fashion cycle did not exist in the formal attires'change, however, since the Period of data were ranged from 1943 to 2000, the 57 years period may not long enough to measure a complete fashion cycle.

• The Journal of the Korea Contents Association
• /
• v.18 no.1
• /
• pp.305-313
• /
• 2018

Public open data is a database or electronic file produced by a public agency or government. The government is opening public data through the open data portals and individual agency websites. However, it is a reality that there is a limit to search and utilize desired public data from the perspective of data users. In particular, it takes a great deal of effort and time to understand the characteristics of data sets and to combine different data sets. This study suggests the possibility of interlinking between data sets by analyzing the common relationship of item names held by public data. The data sets are collected from the open data portal, and item names included in the data sets are extracted. The extracted item names consist of formal context and formal concept through formal concept analysis. The format concept has a list of data sets and a set of item name as extent and intent, respectively, and analyzes the common items of intent end to determine the possibility of data connection. The results derived from the formal concept analysis can be effectively applied to the semantic connection of the public data, and can be applied to data standard and quality improvement for public data release.

• Proceedings of the KSR Conference
• /
• 2007.05a
• /
• pp.1000-1007
• /
• 2007

Recently, 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 error of overlooked requirement specification can be detected using 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 the comparison of other formal specification methods, we choose the Z formal language for applying to the train control system. Using Z is able to realize higher correctness in the requirement specification, and we propose the Statemate of the best solution in formal verification tools for the system modeling and verification. The Statemate makes it possible to prove thoroughly the system execution from the simple graphical modeling of the complicated train control system. Then we can expect that the model-based formal method combining Z with Statemate will be utilized widely for the railway systems due to various strong points.

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