• International conference on construction engineering and project management
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• 2011.02a
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• pp.330-334
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• 2011

Build-operate-transfer (BOT) projects are privatized infrastructure undertakings that face long-term investment risks and uncertainties. To ensure these projects can be completed on time and operated according to performance specifications, governments usually require BOT concessionaires to furnish performance bonds as a security. However, in order to attract investment, governments often provide abandonment rights for concessionaires to deal with investment risks and uncertainties. In the context of real options, these abandonment rights will increase project value, but the furnish of performance bonds will reduce this value. Currently in the BOT context, there is no real option model that can handle explicitly the impact of performance bonds on project value. In this paper, a real option valuation model is derived to deal with this important issue. The Taiwan high-speed rail project is used as a case study to show the applicability of the proposed model.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.31 no.7
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• pp.56-62
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• 2013

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.11
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• pp.2866-2879
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• 2012

Among the various security threats in online games, the use of game bots is the most serious problem. Previous studies on game bot detection have proposed many methods to find out discriminable behaviors of bots from humans based on the fact that a bot's playing pattern is different from that of a human. In this paper, we look at the chatting data that reflects gamers' communication patterns and propose a communication pattern analysis framework for online game bot detection. In massive multi-user online role playing games (MMORPGs), game bots use chatting message in a different way from normal users. We derive four features; a network feature, a descriptive feature, a diversity feature and a text feature. To measure the diversity of communication patterns, we propose lightly summarized indices, which are computationally inexpensive and intuitive. For text features, we derive lexical, syntactic and semantic features from chatting contents using text mining techniques. To build the learning model for game bot detection, we test and compare three classification models: the random forest, logistic regression and lazy learning. We apply the proposed framework to AION operated by NCsoft, a leading online game company in Korea. As a result of our experiments, we found that the random forest outperforms the logistic regression and lazy learning. The model that employs the entire feature sets gives the highest performance with a precision value of 0.893 and a recall value of 0.965.

• Journal of Korea Game Society
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• v.15 no.4
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• pp.69-78
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• 2015

As the online game industry has been growing rapidly, more and more malicious activities to gain economic benefits have been reported as well. Game bot is one of the biggest problems in the online game industry. So we proposed a bot detection method based on the ERG theory of motivation for the first time. Most of the previous studies focused on behavior-based detection by monitoring patterns of the specific actions. In this paper, we applied the motivation theory to analyze user behaviors on a real game dataset. The result shows that normal users in the game followed the ERG theory of motivation in the same way as it works in real world. But in the case of game bots, the theory could not be applied because the game bot has specific reasons, unlike normal game users. We applied the ERG theory to users to distinguish game bot users from normal users. We detected the game bot with high accuracy of 99.78% by applying the theory.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.6A
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• pp.107-114
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• 2008

The Bot is a kind of worm/virus that can be used to launch the distributed denial-of-service(DDoS) attacks or send massive amount of spam e-mails, etc. A lot of organizations make an effort to counter the Botnet's attacks. In Korea, we use DNS sinkhole system to protect from the Botnet's attack, while in Japan "so called" CCC(Cyber Clean Center) has been developed to protect from the Botnet's attacks. But in case of DNS sinkhole system, there is a problem since it cannot cure the Bot infected PCs themselves and in case of CCC there is a problem since only 30% of users with the Botnet-infected PCs can cooperate to cure themself. In this paper we propose a new method that prevent the Botnet's attacks and cure the Bot-infected PCs at the same time.

• Korean Journal of Construction Engineering and Management
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• v.11 no.3
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• pp.134-144
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• 2010

In China, the enhancement of water services has become the most crucial issue confronted with the rapid urbanization and industrialization process. A huge financial gap to meet the demand for water infrastructure and need for adopting advanced operation technology precipitated the rapid growth of PPP over the last 10 years. Diverse schemes of PPP such as TOT, Divestiture, and Management Contract and Lease have been practiced. Local governments and private investors/operator have adjusted their objectives and strategies to avoid potential pitfalls behind BOT projects in China. However, current academic research outcomes do not properly reflect important issues of BOT projects or related case studies in China. This limitation has brought in the lack of assessment of important risks and success factors required for the improvement of the body of risk management. In this regard, this study uses the market analysis method to identify major schemes of PPP water projects and conducts case studies on five PPP projects to identify key risk and success factors in association with each different scheme. It is expected that the risk and success factors identified from the cases will be used as reference to Korean companies which plan to enter the Chinese water market.

• The Journal of Korean Academy of Sensory Integration
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• v.11 no.2
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• pp.41-56
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• 2013

Objective : The purpose of this study tried to present the performed average and range through systematic review about assessment tools that measures the praxis ability of sensory integrative function for foreign and domestic normal children. Methods: With making use of Medline, PubMed, Ovid, Eric, the Library of Congress, National Science and Technology Information Center, Kiss, RISS, and the Google search engine, we searched the name of assessment tool on the basis of the framework of the theory of sensory integration. Target paper was thesis and Journal published from January 2000 to April 2011. Results: Total of 24 papers were retrieved, used assessment tools were Bruininks-Oseretsky Test of Motor Proficiency (BOTMP), Bruininks-Oseretsky Test of Motor Proficiency, Short Form (BOTMP-SF), Bruininks-Oseretsky Test of Motor Proficiency, Second Edition (BOT-2), Bruininks-Oseretsky Test of Motor Proficiency, Second Edition, Short Form (BOT-2-SF), Clinical Observations of Motor and Postural Skills (COMPS), Motor Assessment Battery for Children (MABC), Clinical Test of Sensory Interaction with Balance (CTSIB), and subtest of Sensory Integration and Praxis Test (SIPT). We presented the average and range of assessment tools applied to normal children in each country. Conclusion: A performed result in other cultural and domestic normal children which this study presented will provide a standard in comparison with performance of children with disabilities who are the actual clinical evaluation.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.6
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• pp.1097-1104
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• 2021

Online game-bots are already known for a lot of persons by various ways. It leads to problems such as declining game player's interest, in-game financial crisis, etc. Detecting and restricting of game-bot is now essential. Because both publishers and players get disadvantages from their long term abnormal working. But it is not easy to restrict, because of false restriction risks. Game publishers need to distinguish game-bot from server-side game logs. At last, it should can make reasons for game-bot restriction. In this paper, we classified game-bot users by using daily separated game logs for testing data. For daily-driven detection, we separated total dataset into one day logs. Preliminary detects game-bots with one day logs, and determines total results by using these data. Daily driven detection advantages on detection which contains combined game playing style. Which shows like normal user and game-bot. These methodology shows better F1-score, which one of indicator which demonstrate classification accuracy. It increases from 0.898 to 0.945 by using Random Forest classifier.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.101-104
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• 2006

유행처럼 시도하던 DDoS 공격, 특정 목적을 위한 트로이 목마, 스팸메일을 통한 악성코드 유포, 개인 정보 유출 등 악의적인 공격들이 공격자에 의해 조종당하는 Bot에 의해 쉽게 이루어지고 있으며, 특별한 해결방안이 있는 것도 아니다. 이러한 Bot들이 공격자를 통해서가 아닌 자체적으로 P2P 네트워크를 자가 형성하여 공격한다면 탐지는 더욱 어려워지게 된다. 이와 같은 자가 형성에 대응한 효율적인 방어책을 로컬 시스템 간의 네트워크 모니터링 에이전트를 도입하여 해결하고, 에이전트들이 자가 형성하여 실시간으로 Bot에 대한 정보를 공유하고, 이 정보를 기반으로 시스템을 감시하여 Bot을 탐지하는 방어책에 대해 본 논문에서 기술한다.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.398-401
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• 2009

민간 주도형 사회간접자본 (social overhead capital :SOC) 사업은 BOT(build-operate-transfer)를 비롯하여 대상 프로젝트의 정부 정책 등의 여러 환경의 변경에 따라 다양하게 변형되어 적용되어 BTL(build-lease-transfer), BOO (build-own-operate)등의 여러 기법들을 사용된다. 민간 SOC 사업은 프로 젝트의 규모와 장기에 걸친 공사의 불확실성 때문에 프로젝트의 경제성 분석을 하는 것은 복잡하다. 일반적으로 사용하고 있는 현금흐름 할인모형(discount cash flow model; DCF)은 미래의 불확실성 변수들을 적절히 반영하지 못한다는 한계점을 가지고 있지만 현실적으로 많이 쓰이고 있는 방식이다. 본 논문은 옵션기반모형에 근거한, BOT-옵션가치평가(BOT-OV)모형을 국내 민간 SOC 사업의 경제성 분석을 위해 적용한다. BOT-OV모형을 적용하는 것이 기존 순현재가치(net present value; NPV)방식을 통하여 프로젝트 가치 평가 할 때보다 더 정밀한 경제적 타당성 평가를 할 수 있다는 것을 확인하여 기존의 NPV 평가방식의 방법을 대체할 수 있는 가능성을 확인하는데 의의가 있다고 할 수 있다.