• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.7
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• pp.1132-1137
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• 2014

The purpose of this study was to assess the need for nutritional education in male workers living in Busan, Korea. This study surveyed 310 industrial workers at five companies in Busan using a questionnaire. According to the results, need for nutritional education scored 3.60/5.00 points. The usage rate of mass media as a means of acquiring nutritional information was significantly higher (P<0.001) in subjects in their 50s compared to other age groups. Regarding scores on need for nutritional education according to theme, 'balanced eating habits' showed the highest score, followed by 'food safety', 'diet therapy related to a disease', and 'food hygiene and food poisoning prevention'. In terms of frequency of nutritional education, 29.0% of subjects considered 'biannually' to be desirable, whereas 25.8% and 21.0% considered 'annually' and 'quarterly' to be desirable, respectively. The results of this study suggest that nutritional education for industrial workers should be implemented in various ways in accordance with their characteristics. Furthermore, considering workers' low awareness levels of the need for nutritional education, employees are required to take the education in order to encouraged to improve their nutritional status and commit to a desirable diet.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.11
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• pp.645-651
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• 2014

For blind equalization, we propose a method of updating an equalizer, which generates an error from selectively applying a transmitted symbol constellation and that of induced equivalently from the transmitted symbol constellation and updates the equalizer by using this error. The proposed method, by selectively using the symbol constellation effective for improvement of symbol estimation accuracy and that of effective for improvement of error performance, showed that it is possible to improve the error performance at the same time to open the eye diagram of equalizer output quickly. As a criterion applying the symbol constellation, we used the dispersion of symbol points of equalizer output. In addition, to increase the accuracy of updating an equalizer the error was controlled by using current and previous dispersions. By simulation, under multipath channel with additive noise, we verified the equalization performance of the proposed method for 64-QAM.

• Geotechnical Engineering
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• v.8 no.2
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• pp.71-80
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• 1992

A new constitutive model is proposed for normally consolidated clays. A main skeleton of the proposed model is based on the concepts of the incremental stress-strain theory by Roscoe and Poorooshasb. The equation of the undrained stress path is formulated by introducing the new pore pressure parameter(C), which is the slope of the linear line in the plot of the normalized pore pressure against the stress ratio. Once the stress increment along the constant stress ratio path (followed by untrained stress path) is know, the volumetric strains are calculated from the linear characteristics between void ratio and logarithm of the mean normal stress for any stress ratio. Then the incremental shear strains are successfully predicted by applying the flow rule derived in the modified theory by Roscoe and Burland.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.2
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• pp.191-198
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• 1998

The error are equation of DC-CDMA/MDPSK signal has been derived in m-distribution and Rician fading channels. Predeteception multipath MRC(Maximal Ratio Combining) diversity technique is employed for improving the bit error rate performance. The suitability of modeling a Rician fading environment by properly chosen m-distribution model is examined. Using the derived equation the error performance has been evaluated and shown in figures as a function of PN code sequence length(N), user number(U), multipath number(P), fading index(m), Rician factor(K), number of diversity branches(L) and ($E_b/N_o$). The results show that the error performance in Rician fading agrees well with that in m-distribution fading as fading becomes weak and as user number(U) increases and as multipath number(P) increases and diversity number(L) increases.

• Journal of Astronomy and Space Sciences
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• v.22 no.3
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• pp.263-272
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• 2005

For the Communication, Ocean and Meteorological Satellite (COMS) which will be launched in 2008, an algorithm for finding the precise location of the sun-glint point on the ocean surface is studied. The precise locations of the sun-glint are estimated by considering azimuth and elevation angles of Sun-satellite-Earth geometric position and the law of reflection. The obtained nonlinear equations are solved by using the Newton-Raphson method. As a result, when COMS is located at $116.2^{\circ}E$ or $128.2^{\circ}E$ longitude, the sun-glint covers region of ${\pm}10^{\circ}(N-S)$ latitude and $80-150^{\circ}(E-W)$ longitude. The diurnal path of the sun-glint in the southern hemisphere is curved towards the North Pole, and the path in the northern hemisphere is forwards the south pole. The algorithm presented in this paper can be applied to predict the precise location of sun-glint region in any other geostationary satellites.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.71-72
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• 2007

대역 제한된 DS/SS 시스템의 상관 함수는 최고 값이 나타나는 시점과 함께 이른 또는 늦은 상관시간 옵셋 영역에서 극소 또는 극대로 나타나는 시점을 특징점으로 갖는다. 이 가운데 이른 상관시간옵셋 영역의 상관 함수는 다중경로 신호에 의해 덜 왜곡되기 때문에 이 영역의 상관 함수를 이용해 부호 동기를 추적하여 유지할 수 있다면 EL-DLL (delay lock loop with early minus late discriminator) 보다 추적편이를 줄일 수 있다. 본 논문에 이런 특성을 이용하는 추적편이 완화 기법을 제안하고, 모의실험을 통해 성능을 알아본다.

• Journal of Korea Port Economic Association
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• v.27 no.2
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• pp.195-215
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• 2011

The purpose of this article is to provide data to be utilized for marketing to attract future container cargo to the Korea-China Car Ferry Service and to estimate container traffic for the development of the International Passenger Terminal to be newly built in the Incheon Southern Port. An analysis of container traffic through the Passenger Terminal of Incheon Port showed that the container throughput of Incheon Port comprised 20% of traffic. The export cargo traffic in the International Passenger Terminal, 71.4%, or 111,698 TEU of 156,284 TEU in total, was brought from metropolitan areas. To increase the container traffic of the car ferry service currently concentrated on the metropolitan areas, more endeavor is required to strengthen marketing competence to attract container traffic to other regions apart from the metropolitan areas as well as provide general services.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.4
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• pp.803-810
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• 2017

Recently, social security problems have been caused by the development of the software industry, and a variety of automation techniques have been used to verify software stability. In this paper, we propose a method of automatically detecting a use-after-free vulnerability on Windows system calls using dynamic symbolic execution, one of the software testing methods. First, a static analysis based pattern search is performed to select a target point. Based on the detected pattern points, we apply an induced path search technique that blocks branching to areas outside of interest. Through this, we overcome limitations of existing dynamic symbolic performance technology and verify whether vulnerability exists at actual target point. As a result of applying the proposed method to the Windows system call, it is confirmed that the use-after-free vulnerability, which had previously to be manually analyzed, can be detected by the proposed automation technique.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.1_2
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• pp.78-85
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• 2004

Given a set S of n points in the plane, a minimum-diameter spanning tree(MDST) for the set might have a degree up to n-1. This might cause the degradation of the network performance because the node with high degree should handle much more requests than others relatively. Thus it is important to construct a spanning tree network with small degree and diameter. This paper presents an algorithm to construct a spanning tree for S satisfying the following four conditions: (1) the degree is controled as an input, (2) the tree diameter is no more than constant times the diameter of MDST, (3) the tree is monotone (even if arbitrary point is fixed as a root of the tree) in the sense that the Euclidean distance from the root to any node on the path to any leaf node is not decreasing, and (4) there are no crossings between edges of the tree. The monotone property will play a role as an aesthetic criterion in visualizing the tree in the plane.

• Proceedings of the Korean Society of Computer Information Conference
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• 2024.01a
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• pp.109-111
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• 2024

군사 목적으로 개발된 드론은 최근 다양한 산업 및 민간 분야로 확대되고 있으며, 이러한 확대에 따라, 드론이 급격하게 발전하여, 농업이나 무인 드론 택배와 같은 산업 전반적으로 긍정적인 효과를 창출하는 추세이다. 그러나 이러한 발전에 반하여, 드론에 장착된 카메라를 통한 사생활 침해나 테러 목적으로 활용하는 것과 같은 부정적인 측면이 드러나기 시작하였다. 특히, 드론의 위치와 밀접한 연관이 있는 GPS와 관련하여, 무인 이동체의 특성상, GPS 신호에 의존하여 사용자에게 드론의 위치를 전달하지만, 이러한 GPS 신호를 송신하는 위성은 거리가 매우 멀리 위치하고, 이에 따라, 신호 세기가 비교적 약한 문제점을 가진다. 이와 같은 문제점을 악용하는 GPS 스푸핑 공격이 등장하였으며, 이 공격은 만약 공격자가 GPS 신호를 조작하여 송신한다면, 드론에 장착된 GPS 수신기는 조작된 GPS 위치를 수신하며, 이에 따라, 드론의 제어권을 탈취하거나 충돌 유발, 비정상적인 비행 경로 유도와 같은 문제점이 발생한다. 본 논문에서는 최신의 상용화된 드론을 대상으로, GPS 스푸핑 공격의 취약점을 분석하고 실증한다. 이를 위하여, 공격자가 비행 금지 구역에 해당하는 GPS 신호를 조작하는 것으로 공격을 시도하고, 이에 따른 드론에서 준비된 동작인 강제 착륙과 같은 비정상적인 행위를 유발하여, 드론의 임무 수행 능력을 제한하는 취약점을 분석하고 실험을 통하여 실증한다. 본 논문의 결과를 토대로, 최신 드론에서 발생 가능한 보안 위협을 도출함으로써, 드론의 안전성을 향상시키기 위한 자료로 활용될 수 있을 것으로 사료된다.