• Proceedings of the Korea Society for Simulation Conference
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• 2005.05a
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• pp.34-39
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• 2005

The progress of silicon technology enables to implement a highly complex digital system on a given chip area. However, even the modern design environment is not so efficient to catch up with the progress of process technology. Design reuse is a promising approach to designing such a complex system in an efficient way. However, the rigidness and inflexibility of a model has been an obstacle to design reuse. This paper proposes a high-level model management methodology by introducing attributed AND-OR graph(AOG), a (formal semantics for representing the possible structure of a model. Using the formalism enables a designer to extract, extend and reuse the pre-modeled and pre-verified design. A complete process of constructing a cache operational model, extending the model and extracting executable models is exemplified to show effectiveness of the proposed framework.

• Journal of the Korea Institute of Building Construction
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• v.14 no.3
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• pp.195-206
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• 2014

The main issue of defect dispute is consulting, reviewing, and finally judging as an arbiter. A defect consulting is represented a defect consulting report, but a business custom and a standard of judgment are different each consultants, and have many problems. This study reviews literature studies and institutional researches, set up a research structure. it has 7 indexes that 5 indexes are formal indexes, and the other are qualitative indexed. As a result of case study, formal indexes are respect on the whole. However, each appraiser has different ideas, and, is expected to delay on fixing a construction lawsuit practice. This study suggests to improve a defect consulting report, it is followed. In formal part, suggested to change configuration is adjusted and integrated similar items. In qualitative part, an evaluation system for appraiser and an education program for engineers is suggested.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.1877-1893
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• 2009

Folksonomy is a user-generated taxonomy to organize information by which a user assigns tags to resources published on the web. Triadic datas that indicate relations of between users, tags, and resources, are created by collaborative tagging from many users in folksonomy-based system. Such the folksonomy data has been utilized in the field of the semantic web and web2.0 as metadata about web resources. In this paper, we propose FCA-based folksonomy data mining approach in order to extract the useful information from folksonomy data with various points of view. And we developed tool for supporting our approach. In order to verify the usefulness of our proposed approach and FMT, we have done some experiments for data of del.icio.us, which is a popular folksonomy-based bookmarking system. And we report about result of our experiments.

• Journal of KIISE
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• v.42 no.7
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• pp.823-833
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• 2015

Hybrid system is a dynamic system that is composed of both a continuous and discrete system, suitable for automobile, avionic and defense systems. Various modeling languages and their supporting tools have been proposed and used in the hybrid system. The languages and tools have specific characteristics for their purpose. Electronics and Telecommunications Research Institute (ETRI) proposed a hybrid system modeling language, ECML (ETRI CPS Modeling Language). ECML extends DEV&DESS (Differential Event and Differential Equation Specified System) formalism with consideration of CPS (Cyber-Physical System), which supports modeling and simulation. In this paper, we introduce ECML and suggest a formal definition. The case study specifies a simple vehicle model using the suggested formal definition.

• KIISE Transactions on Computing Practices
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• v.21 no.9
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• pp.604-609
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• 2015

The use of Operating System(OS) virtualization is increasing as it provides many useful features such as efficient use of hardware(HW), easy system migration, and isolation between virtual spaces which prevents errors effecting each other. Recent development in HW has made it possible to use OS virtualization in embedded systems. However, implementing OS virtualization means that a multiple number of schedulers are layered in a system, rendering it difficult to analyze the schedulability of the system and errors are easily produced. Errors in safety critical embedded systems can cause serious damage to life and property; thus, the hierarchical schedulability must be verified. In this paper, we propose a framework which supports formal modeling and verification of hierarchical scheduling systems with UPPAAL.

• Journal of Ocean Engineering and Technology
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• v.27 no.2
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• pp.47-52
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• 2013

A subsea chemical injection system treats blockage problems in a subsea production system. It is important to treat problems quickly, because production delays cause fatal profit losses in a subsea production system. Therefore, the subsea industry requires a relatively higher reliability level for a production system compared to other industries. In this study, a subsea chemical injection system (linked to a control system) to inject chemicals into a subsea X-mas tree was analyzed. By using FSA (Formal Safety Assessment), the risk factors were defined and a quantitative risk analysis utilizing FTA (Fault Tree Analysis) and ETA (Event Tree Analysis) was performed. As a result, the effectiveness of a risk reduction option was evaluated.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.31 no.5
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• pp.46-55
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• 2013

• The KIPS Transactions:PartB
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• v.17B no.3
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• pp.255-262
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• 2010

When a system is developed, requirements document is generated by requirement analysts and then translated to formal specifications by specifiers. If a formal specification can be generated automatically from a natural language requirements document, system development cost and system fault from experts' misunderstanding will be decreased. A pronoun can be classified in personal and demonstrative pronoun. In the characteristics of requirements document, the personal pronouns are almost not occurred, so we focused on the decision of antecedent for a demonstrative pronoun. For the higher accuracy in analysis of requirements document automatically, finding antecedent of demonstrative pronoun is very important for elicitation of formal requirements automatically from natural language requirements document via natural language processing. The final goal of this research is to automatically generate formal specifications from natural language requirements document. For this, this paper, based on previous research [3], proposes an anaphora resolution system to decide antecedent of pronoun using natural language processing from natural language requirements document in Korean. This paper proposes heuristic rules for the system implementation. By experiments, we got 92.45%, 69.98% as recall and precision respectively with ten requirements documents.

• Journal of KIISE:Software and Applications
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• v.29 no.12
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• pp.926-939
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• 2002

The formal specification methods with probability have been demanded in the area of fault real-time systems, in order to specify the uncertainty that the systems can encounter during their execution due to various environmental factors. This paper presents a new formal method with probability. namely Probabilistic Abstract Timed Machine (PATM), in order to analyze and predict system's behavior in dynamical environmental changes, This method classifies the factors into two classes: the variable and the constant. The analysis of system's behavior is performed on the probabilistic reachability graph generated from the ATM specification for the system. The analysis can predict any possibility that the behavior may not satisfy some safety requirements of the system, indicate which variable factors cause such satisfaction, and further recover from this unsatisfying fault state by fixing the variable factors. Consequently the reliability to the fault real-time systems can be improved.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.4
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• pp.167-176
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• 2017

There are increasing policies and safeguards to prevent various human resource losses with the development of automotive industry. Currently ISO26262 $1^{st}$ edition has been released in 2011 to ensure functional safety of electrical and electronic systems and the $2^{nd}$ edition will be released in the second half of 2016 as part of a trend. The E/E (Electrical & Electronics) system requirements verification is required through walk-through, 인스펙션, semi-formal verification and formal verification in ISO 26262. This paper describe the efficiency of model checking for the E/E system requirements verification by applying the product development project of ASIL (Automotive Safety Integrity Level) D for the electrical parking brake system.