• Nuclear Engineering and Technology
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• v.44 no.8
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• pp.929-938
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• 2012

The Computerized Procedure System (CPS) is one of the primary operating support systems in the digital Main Control Room. The CPS displays procedure on the computer screen in the form of a flow chart, and displays plant operating information along with procedure instructions. It also supports operator decision making by providing a system decision. A procedure flow should be correct and reliable, as an error would lead to operator misjudgment and inadequate control. In this paper we present a modeling for the CPS that enables formal verification based on Petri nets. The proposed State Token Petri Nets (STPN) also support modeling of a procedure flow that has various interruptions by the operator, according to the plant condition. STPN modeling is compared with Coloured Petri net when they are applied to Emergency Operating Computerized Procedure. A converting program for Computerized Procedure (CP) to STPN has been also developed. The formal verification and validation methods of CP with STPN increase the safety of a nuclear power plant and provide digital quality assurance means that are needed when the role and function of the CPS is increasing.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3656-3671
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• 2016

Most of the research in the area of wireless communications exclusively relies on simulations. Further, it is essential that the mobility management strategies and routing protocols should be validated under realistic conditions. Most appropriate mobility models play a pivotal role to determine, whether there is any subtle error or flaw in a proposed model. Simulators are the standard tool to evaluate the performance of mobility models however sometimes they suffer from numerous documented problems. To accomplish the widely acknowledged lack of formalization in this domain, a Coloured Petri nets (CPNs) based random direction mobility model for specification, analysis and validation is presented in this paper for wireless communications. The proposed model does not suffer from any border effect or speed decay issues. It is important to mention that capturing the mobility patterns through CPN is challenging task in this type of the research. Further, an appropriate formalism of CPNs supported to analyze the future system dynamic status. Finally the formal model is evaluated with the state space analysis to show how predefined behavioral properties can be applied. In addition, proposed model is evaluated based on generated simulations to track origins of errors during debugging.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.5
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• pp.81-90
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• 2003

Existing web-based system management software solutions show some limitations in time and space. Moreover, they possess such as shortcomings unreliable error message announcements and difficulties with real-time assistance suppers and emergency measures. In order to solve these deficiencies, Wireless Remote Control System was designed and implemented. Wireless Remote Control System is able to manage and monitor remote systems by using mobile communication devices for instantaneous control. The implementation of Wireless Remote Control System leads to these security Problems as well as solutions to aforementioned issues with existing web-based system management software solutions. Therefore, this paper has focused on the security matters related to Wireless Remote Control System. The designed security functions include mobile device user authentication and target system access control. For security verification of these security functions introduced CPN(Coloured Petri Nets) which is capable of expressing every possible state for each stage. And then in this paper was verified its security through PI(Place Invariant) based on CPN(Coloured Petri Nets). The CPN expression and analysis method of the proposed security function can also be a useful method for analyzing other services in the future.

• Journal of the Korea Society for Simulation
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• v.25 no.4
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• pp.21-30
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• 2016

Recently manufacturing companies have used PLC control programs popularly for their automated production systems. Since the life cycle of production process is not so long, the change of the production lines occur frequently. Most of changes happen with modification of the position information and control process of the equipment. PLC control program is also modified based on the fundamental process. Therefore, to verify new PLC program by configuring virtual space according to real environment is needed. In this paper we show a logical modeling method, based on Timed-FSA useful for sequence control and dead-lock prevention. There is a problem wasting user's labor and time when defining a variety of states in a device. To overcome this problem, we propose an extended I-O model based on existing methods by adding a token concept of Petri Nets. Also we will show the usability of the extended I-O modeling through user study.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1099-1102
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• 2004

본 논문은 확장된 역할 기반 접근통제 정책에 적용된 시스템의 명세 및 분석을 위해 컬러드 페트리넷을 이용하는 방법에 관하여 기술한다.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.205-214
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• 2012

The main thing that IT operation managers consider is protecting assets of corporation from system failure and disaster. Therefore, this research proposed a backup system for a disaster recovery. Previous backup method is that if database update occurs, this record is saved in redo log, and if the size of record file is over than expected, this file is saved in archive log in order. Thus, it is possible to occur errors of data loss from the process of data backup which change in real time while changes of database occur. Suggested backup system is back redo log up to database of transaction log in real time, and back a record that can be omitted from previous backup method up to archive log. When recover the data, it is possible to recover redo log in real time online, and it minimizes data loss. Also, throughout multi thread processing method data recovery is performed and it is designed that system performance is improved. To verify stability of backup system CPN(Coloured Petri Net) is introduced, and each step of backup system is displayed in diagram form, and th e stability is verified based on the definition and theorem of CPN.