• Journal of the Korean Society of Systems Engineering
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• v.20 no.1
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• pp.85-94
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• 2024

As systems become more complex today, verifying the safety of complex systems is becoming increasingly important. However, validation activities using actual systems face limitations in terms of time and cost. To overcome these limitations, the functions, characteristics, and operations of physical assets can be implemented in a virtual environment similar to the real world, allowing for validation through simulations under various scenarios. By performing validation in a virtual environment, iterative tests can be conducted through simulations in a realistic virtual environment without physical models during the conceptual design phase. Tests can also be performed under malfunction conditions or extreme conditions. In this study, we introduce a verification method for railway vehicles in a virtual environment and propose a method of applying virtual verification from a life cycle perspective.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.4
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• pp.457-467
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• 2002

In order to simulate cyber attacks and predict network behavior by attacks, we should represent attributes of network components in the simulation model, and should express characteristics of systems that carry out various cyber attacks and defend from these attacks. To simulate how network load may change under the cyber attacks, we extended SSF[9, 10] that is process-based event-oriented simulation system. We added a firewall class and a packet manipulator into the SSFNet that is a component of SSF. The firewall class, which is related to the security, is to simulate cyber attacks, and the packet manipulator is a set of functions to write attack programs for the simulation. The extended SSFNet enables to simulate a network with the security systems and provides advantages that make easy to port already exsiting attack programs and apply them to the simulation evironment. We made a vitual network model to verify operations of the added classes, and simulated a smurf attack that is a representative denial of sevive attack, and observed the network behavior under the smurf attack. The results showed that the firewall class and packet manipulator developed in this paper worked normaly.

• The Journal of the Korea Contents Association
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• v.8 no.12
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• pp.198-206
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• 2008

The fashion in the virtual world is emerging as a new genre. Gammer in virtual community shares the avatars and space for their activities and for flourishing their virtual lives, they start to demand indispensable daily items. The gammer's demands lead to the concept of second life in the virtual world which was introduced in 2003. The trading business system is realized at the virtual world with various daily items, developed by individual programmers, through the virtual money, which may converted into real money. Particularly, fashion industry's inherent nature of snagging on-line trading is no more, now, set to ready in the virtual world let alone various daily virtual items developed by individual programmers. The purpose of this study is, focused on the virtual second life, to introduce the model of fashion business in virtual world and overall informations regarding second life business systems so as to provide the fundamental data for opening the web.3.0 era. Further various fashion items in the virtual world, developed by individual programers, will be another boost for shaping another virtual fashion business genre.