• Journal of the Korean Society of Radiology
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• v.5 no.5
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• pp.277-282
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• 2011

When we keep sitting for a long time, we end up with pain due to changes in the curvature in the waist. This study examined impacts from the wearing of a SPINE-GUARD(belt for the waist stabilization) on a cross-legged sit on variations of the Cobb's angle, lower back pain and trunk flexion angle. 15 men for the examination have watched movies or attended lectures while wearing a belt for 90 minutes per round for every five rounds for two weeks. The Cobb's angle showed a significant decrease from $48.36{\pm}14.57$ before wearing to $28.09{\pm}11.63$ after wearing (p<0.05). Pain decreased from $4.53{\pm}2.36$ before wearing to $2.733{\pm}2.153$ after wearing (p<0.05). The trunk flexion angle also showed a significant decrease from $82.33{\pm}20.30$ before wearing to $70.2{\pm}19.43$ after wearing (p<0.05). Given these findings, the wearing of a SPINE-GUARD seems to affect variations of the Cobb's angle and trunk flexion angle, and decrease of lower back pain.

• Korean Security Journal
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• no.40
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• pp.87-108
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• 2014

In this study, we tried to find ways to minimize the negative effects of workplace bullying by analysing how workplace bullying affects private security guard's job attitude. The results of survey are as follows. First, as the result of analysis how the guard's workplace bullying affects job satisfaction, one of the job attitude, it showed that relational aggression and workplace bullying have a negative effect on their job satisfaction. In other words, job satisfaction decreases as relational aggression and workplace bullying increase. Second, as the result of analysis how the guard's workplace bullying affects their turnover intention, we found that relational aggression and workplace bullying have an effect on turnover intention, especially, relationally workplace bullying has a more effect on their turnover intention than relational aggression, which Is somewhat different from other studies. Study shows that workplace bullying can cause the guard's negative respond and behavior on their job satisfaction, they have to consider transferring another job. Therefore, increasing their job satisfaction and decreasing turnover intention are very important as we are exposed to crimes these days. In this study, we have come with following solutions. First, to increase job satisfaction against workplace bullying, we have to raise the efficiency of their human resources and reduce work ambiguity of actual work burden caused by positive organizational atmosphere and clear responsibility. Second, it is needed to promote personnel exchange between departments and form partnership through regular meetings by targeting common goals to concentrate same interests. At the same time, we have to improve the guard's welfare and working environment by introducing psychological counselling to the victims of bullying.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.9
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• pp.677-685
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• 2011

The reverse osmosis membrane processes have several operational problems. Fouling by inorganic scale occurs on membrane surface due to increases in concentrations over solubility by retaining ions on feed side of the membrane. Inorganic scales could be controlled by antiscalants or acid addition. In this study, three antiscalants having different characteristics were selected and evaluated on efficiency of $CaCO_3$ scale control. The $CaCO_3$ scale was inhibited by the antiscalants : 0.4 mg/L for SHMP, 0.6 mg/L for Spectra Guard, and 3 mg/L for Flocon 150 N. Increasing concentration factors of simulated sea water resulted in increases in antiscalant doses for the scale control. The increases in doses were positively proportional to the concentrate factors used in this study. Spectra Guard, one of the polyacrylate type antiscalants, was the most effective to control $CaCO_3$ scale. The antiscalants with the different scale inhibition time and doses implied the different control mechanisms.

• Convergence Security Journal
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• v.16 no.1
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• pp.13-21
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• 2016

At the present moment when around 60 years have passed after the introduction of private security, there are security instructor and protection specialist guard as government official recognition qualification. This study discussed problems of secondary performance test system among qualification certification items which have been implement ed as government official recognition qualification since 2013. Current qualification certification for protection specialist guard is composed of primary academic test and secondary performance test. Since it is estimated that it is high time to increase clients' satisfaction and public reliability through strict qualification certification for protection specialist guard. Following improvement plans are intended to suggest. First, it is a plan to divide and diversify difficulties of performance test evaluation events. Second, it is a plan to diversify evaluation criteria of performance test. Third, it is a plan to make criteria for selecting specialized performance test evaluation committee. Fourth, it is a new plan of exclusion system to avoid any relation between performance test evaluation committee and applicants. In this respect, institutional improvement should be followed in order to improve specialty of qualification certification of performance test system for protection specialist guard.

• Strategy21
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• s.43
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• pp.57-88
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• 2018

Security situations are fundamentally and rapidly changing on the Korean Peninsula. Above all, as North Korea(NK) is heightening its nuclear and missile capabilities, Republic of Korea(ROK) is facing an existential threat. At the same time, as China's economic, diplomatic and military power is quickly rising, the balance of power is shifting and strategic competition between the Unite States(US) and China is accelerating in the Asia-Pacific region. Under the pressure of development of these situations, ROK seems to face allegedly the most serious crisis in its national security since the end of the Korean War. In the current grim geopolitical situation, maritime security may become the most difficult security challenge for ROK in the years to come. The purpose of this paper is to compare major changes in maritime security affairs of the ROK during last twenty years from 1998 until now(2018). 1998 was when this journal 『Strategy 21』 was published for the first time by the Korea Institute for Maritime Strategy. Then, this paper tries to identify challenges and risks with which this country has to deal for its survival and prosperity, and to propose some recommendations for the government, the Navy, and the Coast Guard as they are responsible for the maritime security of the country. The recommendations of this paper are as follows: strengthen ROK-US alliance and expand security cooperation with regional powers in support of the maintenance of the current security order in the region; building-up of maritime security capacity in preparation for crisis on the maritime domain with the navy targeting to acquire 'a non-nuclear, balance-of-terror capability, to improve interoperability with the Coast Guard based on 'a national fleet,' and to actively pursue innovation in naval science and technology. Finally, this paper proposes that naval capability the country needs in another twenty years depends on how effectively and rigorously the navy put its utmost efforts towards building 'a strongest navy' today.

• Convergence Security Journal
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• v.17 no.4
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• pp.79-87
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• 2017

The U.S. security regulation is under the influence of each state's law; however, they are mostly similar. Among many states which has the longest history of security regulation in the U.S., state of New York has been shown security regulation for a long time. The state of New York has been emphasized the importance of security significantly because it is economically, culturally, and internationally important place at the same time. New York's state law of security business includes: 1. private investigators and bail enforcement agents and watch, guard or patrol agencies license law. 2. Security guard act of 1992~,3. Title 19 New York State's code of rules and regulation (NYCRR). The law of New York City's private security could inspire Korean private security law in many ways. First, administration of professional law and variety of licensure could be an inspiration to the Korean security services. Second, there are intimate partnership between police and private security in the U.S. New York police's private security partnership has been started since 1986 by Area Police/Private Security Liaison (APPL program) and there are about 1,300 of security companies participating. This program provides not only the simple partnership but also giving essential information for promoting public safety.

• Journal of Advanced Navigation Technology
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• v.8 no.2
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• pp.120-128
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• 2004

Although conventional OFDM/QAM modulation scheme using guard interval is robust to channel induced ISI (Inter-Symbol Interference) in time-domain, it is very sensitive to ICI (Inter-Carrier Interference) due to doppler effect in frequency domain. OFDM/OQAM-IOTA modulation scheme utilizes IOTA (Isotropic Orthogonal Transform Algorithm) filter that has orthogonality in time and frequency domain so that it is robust to delay spread and doppler effect. OFDM/OQAM-IOTA system can increase bandwidth effeciency since it does not use guard interval. In this paper, we show the structure of OFDM/OQAM-IOTA and perfect channel estimation scheme for OFDM/OQAM-IOTA system. We also compare OFDM/OQAM-IOTA system and OFDM/QAM system in AWGN and 1-path Rayleigh fading channel. Simulation results show that OFDM/OQAM system outperforms OFDM/QAM system.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2998-3000
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• 2005

The orthogonal frequency-division multiplexing (OFDM) technique is well known to be robust against the frequency-selective fading in wireless channels. It is due to the exploitation of a guard interval that is inserted at beginning of each OFDM symbol. Based or the conventional OFDM and a polyphase filtered orthogonal frequency division multiplexing (PF-OFDM) technique, we developed an adaptive beamforming algorithm for antenna arrays. The proposed algorithm would lead to an efficient use of channel, since it is possible to eliminate a guard interval and also easily suppress interchannel interference at the same time. In this paper, a series of computer simulations have been provided to show the performance of the proposed system.

• Korean Security Journal
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• no.7
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• pp.191-212
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• 2004

According to current record of private security in Korea, more than 107,963 private security guards are employed by 2,051 security guard association. However, it is obvious that there is lack of any kinds of professional license. To ensure the profession of Private Security industry and at the same time to improve the quality of private guard duty, it is necessary to introduce professional license system which is specialized and developed. The kinds of license anticipated are security guards services, armored car services, alarm services, proprietary security services, special guards services, terror, security consultants services, and private investigators. To settle those license system, there should be not only exertion of academic society but also administrative support of government and research of legal office th arrange legal and official structure.

• ETRI Journal
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• v.29 no.4
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• pp.430-436
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• 2007

An OFDM/offset QAM (OQAM)-IOTA system uses the isotropic orthogonal transform algorithm (IOTA) function, which has good localization properties in the time and frequency domains. This is employed instead of the guard interval used in a conventional OFDM/QAM system in order to be robust for multi-path channels. However, the conventional channel estimation scheme is not valid for an OFDM/OQAM-IOTA system due to the intrinsic inter-symbol interference of the IOTA function. In this paper, a condition is derived to reduce the intrinsic interference of the IOTA function. This condition is obtained with the proposed pilot structure used for perfect channel estimation. We also derive the preamble structure appropriate for practical channel estimation of the OFDM/OQAM-IOTA system. Simulation results show that the OFDM/OQAM-IOTA system with the proposed preamble structure performs better than the conventional OFDM system, and it has the additional advantage of an increased data transmission rate which corresponds to the guard interval retrieval.