• Journal of the Korean Society for Nondestructive Testing
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• v.8 no.1
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• pp.30-37
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• 1988

Interfaces, both grain boundaries and phase boundaries, play a very important role in the mechanical behavior of structural materials. The problemis particularly intense in composite materials where interfaces play a primary role in the meehanical response of the composites. This paper will concentrate on the approaches to perform nondestructive evaluation of the interfaces in a man nor in which some measure of the mechanical behavior of the interface can be established. Some of the possible approaches that may have potential for the nondestructive evaluation of interfaces are optical, electronic/ electrical, and acoustic approaches.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.4
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• pp.287-293
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• 2005

Ultrasonic guided waves are gaining increasing attention for the inspection of platelike and rodlike structures. At the same time, inspection methods that do not require contact with the test piece are being developed for advanced applications. This paper capitalizes on recent advances in the areas of guided wave ultrasonics and noncontact ultrasonics to demonstrate a superior method for the nondestructive detection of defects thinning simulating hidden corrosion in thin aluminum plates. The proposed approach uses EMAT(electro-magnetic acoustic transducer) for the noncontact generation and detection of guided waves. Interesting features in the dispersive behavior of selected guided modes are used for the detection of plate thinning. It is shown that mode cutoff measurements provide a qualitative detection of defects thinning. Measurement of the mode group velocity can be also used to quantify depth thinning.

• Journal of Korea Multimedia Society
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• v.9 no.8
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• pp.1030-1036
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• 2006

The rapid proliferation of wireless networks and mobile computing applications has changed the landscape of network security. Anomaly detection is a pattern recognition task whose goal is to report the occurrence of abnormal or unknown behavior in a given system being monitored. This paper presents an efficient rough set based anomaly detection method that can effectively identify a group of especially harmful internal masqueraders in cellular mobile networks. Our scheme uses the trace data of wireless application layer by a user as feature value. Based on the feature values, the use pattern of a mobile's user can be captured by rough sets, and the abnormal behavior of the mobile can be also detected effectively by applying a roughness membership function considering weighted feature values. The performance of our scheme is evaluated by a simulation. Simulation results demonstrate that the anomalies are well detected by the method that assigns different weighted values to feature attributes depending on importance.

• Journal of Korea Game Society
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• v.11 no.6
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• pp.81-93
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• 2011

Identity theft happens frequently in popular MMORPG(Massively Multi-player Online Role Playing Games) where profits can be gained easily. In spite of the importance of security about identity theft in MMORPG, few methods to prevent and detect identity theft in online games have been proposed. In this study, we investigate real identity theft cases of an online game and define the representative patterns of identity theft as the speedy type, cautious type, and bold type. We then propose the automatic identity theft detection model based on the multi-class classification. We verify the system with one of the leading online games in Korea. The multi-class detection model outperforms the existing binary-class one(hacked or not).

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.3
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• pp.627-637
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• 2015

As game item trading becomes more popular with the rapid growth of online game market, the market for trading game items by cash has increased up to KRW 1.6 trillion. Thanks to this active market, it has been easy to turn these items and game money into real money. As a result, some malicious users have often attempted to steal other players' rare and valuable game items by using their account. Therefore, this study proposes a detection model through analysis on these account thieves' behavior in the Massive Multiuser Online Role Playing Game(MMORPG). In case of online game identity theft, the thieves engage in economic activities only with a goal of stealing game items and game money. In this pattern are found particular sequences such as item production, item sales and acquisition of game money. Based on this pattern, this study proposes a detection model. This detection model-based classification revealed 86 percent of accuracy. In addition, trading patterns when online game identity was stolen were analyzed in this study.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.1134-1139
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• 2003

Vibration problems are an intrinsic characteristic in a washing machine owing to rotation working mechanism. Therefore, a right comprehension of working principle and the analysis on dynamic behavior of a washing machine is essential to design anti-vibration or vibration reduction. In this paper, we choose two kinds of a washing machine: a suspension type pulsator/drum type washing machine. Each the structure and working principle of a washing machine is discussed briefly and the dynamic behavior of it is investigated, then, the vibration detection problems of transient or excessive vibration is tented in each category. Some vibration experimented results in a washing machine are presented also.

• Journal of Navigation and Port Research
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• v.32 no.2
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• pp.127-132
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• 2008

The safety degree of navigation for collision avoidance is closely related with the combination between mariner's behavior and navigational environment. The condition of navigational environment is mainly decided by navigable waters, ship traffic, rule of road, sea state, weather and so on. Especially, the condition of navigable waters and ship traffic in navigational environment are ones of the important factors to attain safe navigation when mariners are underway and crossing, head on or overtaking situation. Thus this paper is to analyze the characteristics of mariner's behavior for collision avoidance caused by ship traffic and navigable waters by analyzing the contents of questionnaire and the results of international collaborative research. As a result, it can be concluded that the density of ship traffic and the area of navigable waters affect mariner's ship handling for collision avoidance.

• Korean Journal of Adult Nursing
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• v.14 no.2
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• pp.194-204
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• 2002

Purpose: This study is aimed at showing the effect of work-site health promotion programs for health promoting behavior, cholesterol, and quality of life of middle-aged workers. Method: Thirty-one middle-aged workers were the experimental group and thirty-one were the control group. The 8-week work-site health promotion program was given to the experimental group. After this, health promoting behavior, cholesterol and quality of life were measured by questionnaires for the experimental and control groups. Health promotion theory, flexibility and muscle strength, aerobic exercise, nutrition, stress management, cancer prevention and early detection, smoking and alcohol problems, and summary lecture were all included in the 8-week work-site health promotion program. Health promoting behavior was measured by Park's HPBS, cholesterol was measured by enzyme method, and quality of life was measured by Ro's QOL. Result: The experimental group showed a higher score of health promoting behavior than the control group. There were no differences on cholesterol and quality of life between the experimental and control groups. Conclusion: It is necessary that nurses provide middle-aged workers with work-site health promotion programs to improve health promoting behavior. It's necessary also to re-study this with the pre-post research design.

• The Korean Journal of Emergency Medical Services
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• v.27 no.1
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• pp.79-90
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• 2023

Purpose: The study attempted to improve the health promotion behavior of university students by identifying the factors that affect health promotion behavior and by checking depression, anxiety, and stress levels of university students after the COVID-19 pandemic. Methods: We collected data using a structured questionnaire targeting 170 university students in C-province between December 1 and December 31, 2022. Results: Health promotion behavior had a significantly negative correlation with Depression (r=-.361, p<.001), Anxiety (r=-.191, p=.012), and Stress (r=-.301, p<.001), respectively. The influencing factors of health promotion behavior are gender (r=0.184, p<.001) and depression (r=-0.303, p<.001); the explanatory power is accounted for 15%. Conclusion: A practical method with counseling programs and mental health support services for early detection of risk groups by periodically monitoring the depression state of university students requires practicing health promotion behavior. Therefore, active support and attention should be provided to manage the mental health of university students.

• The KIPS Transactions:PartC
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• v.10C no.2
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• pp.119-124
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• 2003

Although there have been many studies on using finite automata for intrusion detection, it has been a difficult problem to generate compact finite automata automatically. In a previous research an approach to profile normal behaviors using finite automata was proposed. They divided the system call sequence of each process into three parts prefix, main portion, and suffix, and then substituted macros for frequently occurring substrings. However, the procedure was not automatic. In this paper we present algorithms to automatically generate intrusion detection automata from the sequence of system calls resulting from the normal runs of the programs. We also show the effectiveness of the proposed method through experiments.