• Journal of Korea Society of Industrial Information Systems
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• v.12 no.1
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• pp.28-38
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• 2007

In this paper, we implement Microsoft COM software modules for elliptic curve cryptographic applications and analyze its performance. The implemented COM software modules support all elliptic curve key exchange protocols and elliptic curve digital signature algorithm in IEEE 1363 finite fields GF(p) and GF(2m). Since the implemented software modules intend to focus on a component-based software development method, and thus it have a higher productivity and take systematic characteristics to be open outward and to be standardized. Accordingly, it enable a software to be developed easier and faster rather than a method using C library. In addition it support the Microsoft COM interface, we can easily implement secure software applications based on elliptic curve cryptographic algorithms.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.83.1-83.1
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• 2013

선형비점수차를 완벽하게 제거한 비축반사경 이론을 천체 관측용 분광기의 전단 광학계 등에 응용하면 색수차가 없는 기기 제작이 가능하다. 이러한 비축 반사경은 DTM(Diamond Turning Machine)을 이용하여 알루미늄으로 만들면 제작 시간이 단축된다. 그러나 DTM을 이용해 알루미늄과 같이 무른 금속을 가공할 경우 툴마크가 발생하게 된다. 툴마크는 회절현상을 발생시키며 이러한 회절현상은 알루미늄 반사경을 이용한 광학계 개발에 제약이 된다. 툴마크는 DTM 가공 이후 연마를 통해 제거할 수 있지만 알루미늄의 무른 특성으로 인해 연마 과정에서 반사경의 형상이 변할 가능성이 크다. 이러한 알루미늄 반사경의 형상 변화를 최소화하기 위한 방법으로는 알루미늄 반사경 표면에 무전해니켈도금을 하는 것이다. 하지만 도금 과정에서 반사경의 형상이 변할 가능성이 있기 때문에 두가지 방법을 사용하여 툴마크를 제거할 계획이다. 첫 번째 방법은 DTM 가공된 알루미늄 반사경을 5 um의 무전해니켈도금 이후 연마하여 툴마크를 제거하고 반사율 증가를 위해 그 위에 다시 알루미늄 코팅을 하는 방법니다. 두 번째 방법은 100 um의 무전해니켈도금 이후 DTM 가공을 하고 다시 연마를 통해 툴마크를 제거하는 방법이다. 이번 발표에서는 툴마크를 제거하기 위한 2가지 방법의 장단점을 확인하고 툴마크를 제거한 알루미늄 반사경을 제작하기 위한 과정을 설명하였다. 본 연구에서 개발한 비축 반사경은 서울대학교 창의연구단의 광학/적외선 카메라 CQUEAN의 차세대 모델에 적용할 계획이다.

• Journal of Korean Biological Nursing Science
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• v.11 no.2
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• pp.143-148
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• 2009

Purpose: The purpose of this study was to identify the affecting factors on the health promoting behaviors of the clinical nurses. Methods: This study was a trans-sectional survey research. The subjects of this study were 206 clinical nurses. The data were collected by questionnaires and medical records. Results: There were significant positive relationships between health promoting behavior and perceived health status, job satisfaction, familial support. There were significant negative relationships between health promoting behavior and depression. The significant affecting factors on the health promoting behaviors of the clinical nurses were depression, familial support and job satisfaction. These 3 factors explain 18.6% of the health promoting behaviors of the clinical nurses. Conclusion: This study provides the empirical evidence that health promoting behaviors of the clinical nurses are closely related to depression, familial support, and job satisfaction. This results can be used to develop health promoting program for clinical staff nurses.

• Progress in Superconductivity and Cryogenics
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• v.5 no.3
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• pp.34-37
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• 2003

A 1 MVA single-phase high temperature superconducting (HTS) transformer with BSCCO-2223 wire was designed in this paper. The rated voltages of each sides of the transformer are 22.9 kV and 6.6 kV respectively. Double pancake HTS windings arranged reciprocally will be used for the transformer windings, because of the advantages of insulation and distribution of surge voltage in case of a large power and high voltage transformer. Single HTS wire was used for the primary windings and four parallel wires were used for the secondary windings of the transformer with transposition. A core of the transformer was designed as a shell type core separated with the windings by a cryostat made of GFRP with a room temperature bore. The operating temperature of the HTS windings will be about 65K with sub-cooled liquid nitrogen. A cryogenic cooling system using a GM-cryocooler for this HTS transformer by natural convection of liquid nitrogen was designed. This type of cooling system can be a good option for compactness, efficiency, and reliability of the HTS transformer.

• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.148-153
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• 1999

We conducted this survey to find out the quality of ground water used for agriculture. Water samples mainly collected from plastic film houses which were located at Yongin City, Pyungtaek City, Hwasung Kun and Suwon City in Kyonggi Province. We measured EC, COD, ammonium, nitrate, sulfate, chlorite etc., and sampled three times in 1998. According to our survey, the ground water was suitable for irrigation purpose, but nitrate concentrations in ground water used in the intensive plastic film houses were high enough to require a special consideration or. the water and fertilizing management. On occasion of Pyungtaek, these results showed us specific. There are many differences among regions but aren't among periods on the part of nitrate concentrations. We found ground water quaky got worse as EC and nitrate value were going up. And there was high correlation between them.

• Journal of the Korea Computer Industry Society
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• v.10 no.4
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• pp.167-176
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• 2009

In this paper, we propose an improved SHACAL-1 of the same encryption and decryption with a simple symmetric layer. SHACAL-1 has 4 rounds, and each round has 20 steps. Decryption is becoming inverse function of encryption, In this paper, we proposed SHACAL-1 are composed of the first half, symmetry layer and the last half. The first half with SHACAL-1 encryption algorithm 1 round does with 10 steps and composes of 4 round. The last half identically with SHACAL-1 decryption algorithm, has a structure. On the center inserts a symmetry layer, encryption and decryption algorithm identically, composes. In the experiments, the proposed SHACAL-1 algorithm showed similar execution time to that of the SHACAL-1. Thanks to the symmetric layer, the proposed algorithm makes it difficult for the attacks which take advantages of high probability path such as the linear cryptanalysis, differential cryptanalysis. The proposed algorithm can be applicable to the other block cipher algorithms which have different encryption and decryption and useful for designing a new block cipher algorithm.

• Korean Journal of Biological Psychiatry
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• v.3 no.2
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• pp.162-169
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• 1996

An association study with korean schizophrenic patients(N=75) and normal controls(N=87) was performed to find the relationship between D6S274 polymorphism and schizophrenia using polymerase chain reaction. Nine different alleles of a dinucleotide polymorphism on D6S273 locus were observed in both group. When we compared the frequencies of alleles between schizophrenics and normal controls, there was no significant difference between two groups. To increase homogeneity of schizophrenic group, we divided schizophrenic group by clinical phenotypes such as DSM-IV diagnostic subtype, family history, negative and positive symptoms(PANSS), soft neurologic signs(NES-K). Then we compared the frequencies of alleles among subgroups of clinical phenotypes. there was only significant difference between two subgroups on soft neurologic signs(p<0.05). Although our findings fail to provide on evidence of association between schizophrenia and D6S274 locus, follow-up investigation of this locus may be needed in homogeneous subtypes of schizophrenia and schizophrenic pedigrees.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.8
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• pp.727-734
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• 2015

Currently, polyurethane (PU) foam is used in most refrigerators as a thermal insulator, whereby the material contributes to structural stiffness by joining the refrigerator cases; however, refrigerator PU foam induces a low thermal efficiency and results in environmental contamination. To resolve these issues, we applied the vacuum insulated panel (VIP) instead of PU form in the design of a new refrigerator type, whereby the VIP significantly contributes to the rectification of the previously mentioned issues. The VIP structure, however, cannot effectively hold refrigerator cases, so the present study investigated a new frame-structure concept by evaluating the stiffness using the topology optimization of refrigerator cases. Lastly, a refrigerator prototype comprising an optimal frame structure was built and subject to a stiffness test, and a comparison of the test results with those of a conventional refrigerator show that the structural stiffness of the prototype is sufficiently effective.

• Ocean and Polar Research
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• v.33 no.2
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• pp.99-111
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• 2011

To estimate the effects of limitation nutrients for phytoplankton growth and its influences on short-term variations of a winter phytoplankton community structure, we investigated the abiotic and biotic factors of surface and bottom waters at 20 stations of inner and offshore areas from 6 to 7 February in Gwangyang Bay, Korea. Also, several algal bio-assay studies were conducted to identify any additional nutrient effects on phytoplankton assemblage using surface water for the assay. The dominant species in the bay was diatom Skeletonema costatum, which occupied more than 70% of total species in most stations (St.1-16) of the inner bay. According to a cluster and multidimensional scaling (MDS) analysis based on phytoplankton community data from each station, the bay was divided into three groups. The first group included stations from the south-western parts of Myodo lsland, which can be characterized as a semien-closed eutrophic area with high phytoplankton abundance. The second group included most stations from the north-eastern part of Myodo lsland, influenced indirectly by surface water currents from offshore of the bay. The standing phytoplankton crops were lower than those of the first group. The other cluster was restricted to samples collected from offshore of the bay. In the bay, silicon (Si) and phosphorus (P) were not a major limiting factor for phytoplankton production. However, since the DIN: DIP and DSi: DIN ratios clearly demonstrated that there were potential stoichiometric N limitations, nitrogen (N) was considered as a limiting factor. Based on the algal bio-assay, in vivo fluorescence values in N (+) added experiments were higher compared to control and P added experiments. Our results suggested that nitrogen may act as one of the most important factors in controlling primary production during winter in Gwangyang Bay.

• Journal of the Korean Institute of Gas
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• v.16 no.5
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• pp.28-34
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• 2012

Material degradation of Cr steels in using for boiler tubes was studied in the relation of microstructural changes like carbide behavior and mechanical properties of hardness and creep-rupture life. The carbide dissolution was occurred in 2Cr steel of T22 during high temperature operation. And the grain refinement within martensite lath of 12Cr steel of X20 was derived by the high temperature-long time exposure. But the specific phenomena of material degradation which might be represented by hardness or creep-rupture time of the used tubes were not shown in all the tubes of T22 and X20 even in the fire-side using.