• Journal of KIISE:Information Networking
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• v.30 no.1
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• pp.30-37
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• 2003

In this paper, a discrete wavelet transform (DWT)-based watermarking system is proposed. The main feature of proposed system is that the embedding system uses adaptive thresholds to control the trade-off between the qualify of the watermarked image and the capacity of the watermark, and the trade-off between the quality and robustness of the watermarked image. Also, the extracting system rebuilds threshold according to various attacks and decides a watermark bit from the least distorted coefficient after measuring the distortion of coefficient. Finally, a new measure to detect the uniqueness of watermark is proposed. The experimental result shows that the proposed watermarking system is robust against conventional signal processing and intentional attacks.

• The Korean Journal of Pain
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• v.6 no.1
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• pp.109-116
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• 1993

In March of l992, We performed two intentional total spinal blocks for the relief of pain. This was for 2 cases of post-traumatic cervical syndrome whose various symptoms were chronically unresponsive to the usual conservative treatments. We regularly checked the blood pressure, pulse rate, oxygen saturation and observed clinically the changes of respiration, consciousness, lid and light reflexes during the total spinal block. Pain relief was evaluated by using the Visual Analog Scale which is designed to measure the subjective intensity of pain. The results were as follows; 1) The effectiveness of total spinal block was 60% in case 1, 40% in case 2. 2) We observed two complications from the procedure. Firstly during the block, these were transient periods of hypotension. Following the block, accidental procedures related direct neural trauma resulted in anterior chest wall pain. In conclusion we believe that total spinal block is a satisfactory and reliable method for the treatment of post-traumatic cervical syndrome.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.5
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• pp.793-800
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• 2010

GPS spoofing is an intentional interference which uses the mimic GPS signals to fake the receivers. The generic GPS receiver is hard to recognize the spoofing signal because the spoofer generates the fake signals as close as possible to the GPS signal. So the spoofer can do critical damage to public operations. This paper introduces a basic concept of spoofing and analyzes the effect of the spoofing signal to the GPS receiver. Also for stand-alone GPS receivers, two anti-spoofing methods are implemented : RAIM based method and the SQM based method. To evaluate the performance of anti-spoofing method, the software based spoofing signal generator and GPS signal generator are implemented. The performance of the anti-spoofing methods obtained using the output of the software based GPS receiver shows that SQM based method is more effective when multiple spoofing signals exist.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.1
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• pp.20-29
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• 2011

This paper proposes critical load following back-up system using MCFC stack. This system enables MCFC generation system to supply power to critical load without UPS and to generate rated power under grid fault state. This back-up system includes 'Load Leveler' that is connected with 3-phase inverter and is controlled by additional algorithm that includes critical load following. The proposed system and algorithm are verified by computer simulation based on 5kW system.

• Safety and Health at Work
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• v.7 no.1
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• pp.1-5
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• 2016

Background: Several studies have investigated the relationship between specific occupations and suicide mortality, as suicide rates differ by profession. The aim of this study was to investigate suicide mortality ratios across broad occupational groups in Greece for both sexes in the period 2000-2009. Methods: Data of suicide deaths were retrieved from the Hellenic Statistical Authority and comparative mortality ratios were calculated. Occupational classification was based on the International Classification of Occupations (ISCO-88) and the coding for Intentional self-harm (X60-X84) was based on the international classification of diseases (ICD-10). Results: Male dominant occupations, mainly armed forces, skilled farmers and elementary workers, and female high-skilled occupations were seen as high risk groups for suicide in a period of 10 years. The age-productive group of 30-39 years in Greek male elementary workers and the 50-59 age-productive group of Greek professional women proved to have the most elevated number of suicide deaths. Conclusion: Further research is needed into the work-related stressors of occupations with high suicide mortality risk and focused suicide prevention strategies should be applied within vulnerable working age populations.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.4
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• pp.677-682
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• 2002

Break-in is an intentional treatment to enhance the performance life of machinery parts and to maintain static friction behavior. Most studies on break-in have concerned only about surface conditions such as roughness or film formation. But the exact mechanism of break-in has not been found yet. Friction, scuffing behavior and wear of AISI 1045 were studied in relation to break-in and residual stress. The cylinder-on-disk type tribometer was used with the line-contact geometry. Scuffing tests were carried out using a constant load of 730N. In the break-in procedure the step load was applied from 100N to 200N. In this experiment, it was found that the break-in helps compressive residual stress to be formed well enough to enhance the scuffing life during the scuffing test. Specimens that had high compressive residual stress induced by shot-peening show better wear resistance than those were not shot-peened. Results of scuffing test, break-in procedure and wear amount in relation to residual stress have been discussed.

• The Mathematical Education
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• v.50 no.2
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• pp.165-184
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• 2011

The purpose of this study is to detect the possibility of the development of conception of a graph and the formula with the absolute value through context questions, and also to investigate the effectiveness of the each step of the mathematical modeling activities in helping students to have the conception. The research was conducted to analyze the process of development of the mathematical conception by applying the mathematical modeling activities two times to subjects of two academic high school students in the first grade. The results of the study are as follows: Firstly, the subjects were able to comprehend the geometric conception of the absolute value and to make the graph and the formula with the sign of the absolute value by utilizing the condition of the question. Secondly, the researcher set five steps of the intentional mathematical model in order to arouse the effective mathematical notion and each step performed a role in guiding the subjects through the mathematical thinking process in consecutive order; consequently, it was efficacious in developing the conception.

• Journal of the Korean Society for Heat Treatment
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• v.29 no.5
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• pp.216-219
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• 2016

$SnO_2$ single layer films (100 nm thick) and 2 nm thick Ni intermediated $SnO_2$ films were deposited on glass substrate by RF and DC magnetron sputtering without intentional substrate heating and then the influence of the Ni interlayer on the electrical and optical properties of the films were investigated. As deposited $SnO_2$ single layer films show the optical transmittance of 82.6% in the visible wavelength region and a resistivity of $6.6{ \times}10^{-3}{\Omega}cm$, while $SnO_2/Ni/SnO_2$ trilayer films show a lower resistivity of $2.7{ \times}10^{-3}{\Omega}cm$ and an optical transmittance of 76.3% in this study. Based on the figure of merit, it can be concluded that the intermediate Ni thin film effectively enhances the opto-electrical performance of $SnO_2$ films for use as transparent conducting oxides in flexible display applications.

• Journal of Information Technology Services
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• v.14 no.4
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• pp.81-104
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• 2015

Intentional information systems (IS) misuse is a serious problem in many organizations. This study aims at developing the theoretical framework of deterring IS misuse on the basis of Nagin's General Deterrence Theory (GDT) which is very famous in the area of socio-criminology. Applying GDT to the IS misuse situation could be reasoned that the perceived certainty and the perceived severity of sanctions associated with committing IS misuse have positive impact on deterring the deviant behaviors. Also, these two constructs (certainty of sanctions and severity of sanctions) could be inferred to be influenced by the four types of IS security countermeasures (security policies, security awareness program, monitoring practices and preventive security software) derived through critically reviewing IS security-relevant literature. The proposed research model and ten hypotheses were empirically analysed using structural equation modelling with the data collected by conducting a questionnaire survey of staff members in business organizations in Korea. As a result, it was found that five ones of ten hypotheses were supported. It is thought that this study makes theoretical contribution to expanding research area of IS security and also has strong implications for IS security management practices within organizations.

• Journal of Welding and Joining
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• v.34 no.4
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• pp.48-54
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• 2016

The use of Zn coated steel has increased in the automotive industry due to its excellent corrosion resistance. Conventionally the BIW(body-in-white) structure and the hang-on parts have been made of Zn coated steel and more recently Zn coated steel began to be applied in the chassis parts. During gas metal arc (GMA) welding of the chassis part, lap fillet joint used to be adopted but spatter generation and porosities are most important concerns. In the industrial applications, an intentional joint gap was made to avoid the weld defects but it is not easy to control the size of joint gap. In this research, gas tungsten arc (GTA) is combined with GMA welding where GTA precedes GMA. As pulsed arc was adopted as GMA, GTA was oscillated along the longitudinal direction by pulsing GMA, but the arc oscillation did not disturb the molten droplet transfer of GMA welding. By increasing the distance between GTA and GMA, the length of weld pool increased and porosity could be reduced. Moreover porosity in the welds was fully removed when the distance between two arcs was 15 mm.