• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.349-351
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• 2004

STATEMATE는 Statecharts로 시스템의 행위를 설계하는 도구이다. 근래 들어. STATEMATE MAGNUM은 설계 뿐 아니라 모델체킹을 이용한 정형검증의 기능을 가지고 있다. 모델체킹은 상태 기반의 설계명세 된 시스템을 시제 논리로 그 요구 명세를 기술하여 설계명세가 요구명세를 만족시키는지를 검증하게 된다. 하지만 설계명세가 큰 경우, 모델체킹 시 상태폭발을 일으켜 시스템을 검증하지 못하게 한다. 모델체킹의 상태 폭발을 줄이기 위해서는 기본적으로 모델체커의 알고리즘을 개선시키거나, 모델을 추상화시킨다. 본 연구에서는 모델을 추상화시키더라도 검증 결과에는 별 영향을 주지 않는 부분을 추상화하고, 검증 결과에 직접 적인 영향을 주는 부분을 상세 명세하는 기법을 적용하여 실시간 운영체제의 코드를 어떻게 검증을 하는지를 보여준다.

• Journal of KIISE:Software and Applications
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• v.29 no.5
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• pp.345-354
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• 2002

There have been many researches about monitoring and checking the implementations during run-time using formal requirement specification. They usually adopt temporal logics or their extensions to specify the requirements for the implementations. However, most of the systems fail to support the specification of requirements fir dynamic systems - systems whore components are created and removed during run-time. Unlike analysis or design models, most actual implementations are dynamic, so the notion of instances should be employed in the property specification language. In this paper, we show how we can monitor and check Java programs using our temporal logic for dynamic systems (HDTL). We suggest a framework in which the execution of Java programs are monitored and chocked against given HDTL requirements.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4543-4552
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• 2010

A leader is a special process who roles as the coordinator within multiple processes of a group. In a distributed system, leader election is the procedure of electing a coordinator. This is a very important issue for building fault-tolerant distributed systems. When two normal mobile ad hoc networks are merged, there are two leaders. This violates the safety property, so a mechanism to detect and handle are required. In mobile ad hoc distributed computing system, we propose a leader competition protocol and to prove the temporal logic to it. This solution is based on the group membership detection algorithm.

• The Transactions of the Korea Information Processing Society
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• v.4 no.4
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• pp.1013-1024
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• 1997

In the traditional object modeling methodologies, the object model can be said as formal since it has been based on rich semantic model. But almost of all methodolgies lack in formality the dyamic model and modeling process. Dynamic model cannot represent exctly the timing constraints and the interaction among the objects, which are very important features in real-time and multimedia system. In this paper, we formalize the synamic moedl and modeling proxess based on object behavior and state. This model defines the object state space using the concepts in algebra stucture and defines the object behavior func-tion. Also this model can formalize object kifecycle and conurrency among the objects usint the temporal logiction. Also this model can frlmaize object lifecycle and conurrency among the objects using the tempral logic and behavior founction. We apply firing rules to behacior function for modeling the dependency of interaction among the objescts.

• Journal of Korea Multimedia Society
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• v.13 no.7
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• pp.950-959
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• 2010

The Election paradigm can be used as a building block in many practical problems such as group communication, atomic commit and replicated data management where a protocol coordinator might be useful. The problem has been widely studied in the research community since one reason for this wide interest is that many distributed protocols need an election protocol. However, mobile ad hoc systems are more prone to failures than conventional distributed systems. Solving election in such an environment requires from a set of mobile nodes to choose a unique node as a leader based on its priority despite failures or disconnections of mobile nodes. In this paper, we describe a solution to the election problem from mobile ad hoc computing systems and it was proved by temporal logic. This solution is based on the Group Membership Detection algorithm.

• Journal of Korea Game Society
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• v.4 no.1
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• pp.58-66
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• 2004

This paper uses counterexamples for solving reachability games. An objective. of the game we consider here is to find out a minimal path from an initial state to the goal state. We represent initial states and game rules as finite state model and the goal state as temporal logic formula. Then, model checking is used to determine whether the model satisfies the formula. In case the model does not satisfy the formula, model checking generates a counterexample that shows how to reach the goal state from an initial state. In this way, we solve many of small-sized Push Push games. However, we cannot handle larger-sized games due to the state explosion problem. To mitigate the problem, abstraction is used to reduce the state space to be che cked. As a result, unsolved games are solved with the abstraction technique we propose inthis paper.

• Journal of KIISE:Software and Applications
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• v.30 no.3_4
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• pp.212-218
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• 2003

State invariant is a property that holds in every reachable state. It can be used not only in understanding and analyzing complex software systems, but it can also be used for system verifications such as checking safety, liveness, and consistency. For these reasons, there are many vital researches for deriving state invariant from finite state machine models. In previous works every reachable state is to be considered to generate state invariant. Thus it is likely to be too complex for the user to understand. This paper seeks to answer the question `how to simplify state invariant\ulcorner`. Since the complexity of state invariant is strongly dependent upon the size of states to be considered, so the smaller the set of states to be considered is, the shorter the length of state invariant is. For doing so, we let the user focus on some interested scopes rather than a whole state space in a model. Computation Tree Logic(CTL) is used to specify scopes in which he/she is interested. Given a scope in CTL, mixed reachability analysis is used to find out a set of states inside it. Obviously, a set of states calculated in this way is a subset of every reachable state. Therefore, we give a weaker, but comprehensible, state invariant.

• Journal of The Korean Association For Science Education
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• v.34 no.2
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• pp.175-186
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• 2014

This study investigated the influences of pair activity on characteristics of science imaginary pictures drawn by elementary school students and their perceptions of science imaginary drawing. To do this, fourth graders (N=123) from one of the elementary schools were selected and assigned to individual science imaginary drawing (n=61) and paired science imaginary drawing (n=62) groups. The students of each group were administered the questionnaires. The analyses of the results indicated that pair science imaginary drawing was useful in some cognitive aspects (e.g., the understanding of science imaginary drawing, the diversification of topics and times, the generation of scientific ideas, and the elaboration of the pictures) and motivational aspects (e.g., the inducement of interest and intimacy about science, interest about science imaginary drawing, and sociability with friends). However, there were some limitations in positively changing the perceptions of some cognitive aspects (e.g., the acquirement of new scientific knowledge, the remembrance of scientific knowledge, the improvement of the ability to construct scientific logics, and the improvement of scientific imagination) and aesthetic aspects (e.g., the improvement of the abilities to express themes in drawing, paint the picture, and complete the works of art). In addition, the difficulties in imagining, selecting the subject, and expressing could not be overcome; a few disadvantages in the lack of discussion skills were also pointed out.