• Journal of Internet Computing and Services
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• v.3 no.2
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• pp.79-85
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• 2002

In open communication architecture, application systems consist of objects distributed in lots of computing nodes. To reduce complexity of development. and management of distributed software, to manage efficiently distributed objects and to provide realtime service, the mechanisms for object group management and communication are needed in distributed environment. In this paper we compose object groups and provide reliable group communication mechanism based on CORBA which can adopt a new service without lots of changes on existing system. Group consist of some subgroups that subgroup manager manages for improving the efficiency of group management and message ordering is kept by using sequencer, Communication method among groups uses multicast based on paint to point communication as well as IP multicast and we provide high performance by using selective retransmission of message through message history, We analyze the performance of the proposed mechanism through simulation in distributed environment.

• The Journal of Korean Society for Radiation Therapy
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• v.28 no.1
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• pp.27-34
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• 2016

Purpose : Retrospective evaluation of setup changes using the corrected position during helical tomotherapy Materials and Methods : Head and neck cancer patients were randomly sampled and summarized into 3 groups: Group 1(32) Brain, Group 2 2(28)Maxillar, Nasal cavity, Group 3 (35) Nasopharynx(NPX), Tongue, Tonsil, and Oropharynx(OPX). In 3 groups, the statistical tests based on repeated measurements among 30 times of the duration of treatment by applying X, Y, Z axis errors, roll, weight changes, and vectors as variables. Results : The statistical test results showed that there was no difference between x-axis (p = 0.458) and y-axis (p=0.986) and in roll (p = 0.037), weight change (p <0.001), and the vector (p <0.001). In addition, the pattern between the three groups based on the fraction revealed no difference in x-axis (p = 0.430) and roll (p = 0.299) but a difference in y-axis (.023), weight change (p = 0.001), and vector (p = 0.028). Conclusion : The results of the retrospective evaluation found the change in the group 3 with respect Y, Z, weight, and vector and a larger random error during the treatment including low neck.

• Electronics and Telecommunications Trends
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• v.8 no.4
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• pp.157-162
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• 1993

본 연구는 아날로그 신호를 사용하는 공중교환 전화망과 접속되는 그룹 3(G3) 팩시밀리의 화상 품질을 측정하는 방법을 제시하였다. CCITT(현 ITU-TS) 표준시험 도표 No.2를 이용하여 전송된 화상에 대한 평가는 설문조사를 통해 평가되었고, 그것들은 MOS(Mean Opinion Score) 방법에 의해 계량화되었다. 설문지의 결과에 대한 상관 분석을 통해 문항을 하나의 종합 평가 문항으로 줄일 수 있음을 살펴보았다. 그리고 그 점수들의 평균들에 대한 차이를 분석함으로써 팩시밀리 화상 품질에 영향을 미치는 요인들의 유의성을 검정하였다. 유의성을 검정하는 방법들로 t 검정법과 Vander Waerden Scores 방법을 제시하였다. 그리고 검정 결과 점수 평균이 유의하지 않은 그룹들을 하나의 그룹으로 하여 그 그룹에 있어서 점수 히스토그램을 구하였다. 이 히스토그램을 하나의 정규 분포 곡선으로 근사시켜 팩시밀리 화상 품질 평가치를 살펴보았다.

• Review of KIISC
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• v.32 no.4
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• pp.77-84
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• 2022

2020년 8월 5일 통합 개인정보보호법 [3]이 본격적으로 시행되면서 데이터의 보호와 활용을 동시에 만족할 수 있는 가명처리 개념이 도입되었다. 여러 개인정보처리자로 수집된 가명정보를 결합하기 위한 결합 관리기관이 지정되고 있다. 개인정보보호 국제표준은 관행이나 기술을 국제표준으로 개발하여 상호 연동이 가능한 서비스를 제공할 수 있을 뿐만 아니라 제품이나 서비스의 경쟁력을 강화하는데 활용할 수 있다. 개인정보보호 국제표준화를 주도적으로 추진하고 있는 대표적인 국제표준화 그룹은 국제표준화위원회/전기위원회 합동위원회 1/서브위원회 27/작업그룹 5 (ISO/IEC JTC 1/SC 27/WG 5)를 들 수 있다. 이 그룹의 의장님 독일 쾨테대학 Kai Rannenberg 교수가 맡고 있다. 여기서는 2020년 4월 전자회의 이후에는 개인정보보호 분야 3건의 국제표준을 채택하였다. 차기 회의는 2022년 9월 룩셈부르그에서 펜데믹 이후 최초로 대면과 비대면으로 개최될 예정이다. 본 고에서는 이 그룹에서 2020년 4월 이후 추진되고 있는 개인정보보호 관련 국제표준화 동향을 제시하고자 한다. 또한 지난 4월 SC27 WG5 전자 회의에서 논의된 개인정보보호 관련 주요 표준화 이슈와 대응 방안을 제시한다.

• Progress in Superconductivity and Cryogenics
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• v.8 no.3
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• pp.41-44
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• 2006

This study introduced waste water treatment method by superconducting HGMS(High Gradient Magnetic Separation). HGMS treatment method is high efficient method for various waste water, we have surveyed superconducting magnetic separation technology. We fabricated the prototypes of magnetic matrix filter consisting of stainless steel mesh, which is a core component in the magnetic separation system. In our basic preliminary experiment using HGMS, it was made clear that the fine para-magnetic particles in the wasted water obtained from steelmaking process of POSCO can be separated with high efficiency.

• Korean Journal Plant Pathology
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• v.12 no.1
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• pp.41-46
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• 1996

본 실험은 이병 딸기의 조직에서 분리 동정된 시들음병균(Fusarium oxysporum f. sp. fragariae) 균주들의 유？거 변이를 random amplified polymorphic DNA(RAPD) marker들을 이용하여 조사하였다. 총 24개의 딸기 시들음병 균주들의 DNA를 주형으로 하여 16개의 random 10-mer primer들을 사용하여 증폭시킨 결과 총 231개의 marker들을 이용하여 유전적 변이를 조사해 본 결과 크게 RAPD I과 RAPD II의 2개 그룹으로 나눌 수 있었다. RAPD I그룹에 속하는 균주는 VCG A에 속하는 Y1, K1, K2, K3, K4, N2, N3, N4-1, N6-1, N6-2, N8, N9, N10, M1-2-1 균주, VCG B에 속하는 M4-1 균주 그리고 VCG C에 속하는 N1, Y2 균주들이었고, RAPD II그룹에는 VCG B에 속하는 M1-1, M2-2-1, M2-4-2, M3-2, M3-3-2 균주와 VCG D에 속하는 N1 1 균주가 속하였다. 이들 2그룹 간에는 31%의 유사성이 있었다.

• Electronics and Telecommunications Trends
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• v.33 no.6
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• pp.12-23
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• 2018

In this paper, we review the technical trends of diamond and gallium oxide ($Ga_2O_3$) semiconductor technologies among ultra-wide bandgap semiconductor technologies for harsh environments. Diamond exhibits some of the most extreme physical properties such as a wide bandgap, high breakdown field, high electron mobility, and high thermal conductivity, yet its practical use in harsh environments has been limited owing to its scarcity, expense, and small-sized substrate. In addition, the difficulty of n-type doping through ion implantation into diamond is an obstacle to the normally-off operation of transistors. $Ga_2O_3$ also has material properties such as a wide bandgap, high breakdown field, and high working temperature superior to that of silicon, gallium arsenide, gallium nitride, silicon carbide, and so on. In addition, $Ga_2O_3$ bulk crystal growth has developed dramatically. Although the bulk growth is still relatively immature, a 2-inch substrate can already be purchased, whereas 4- and 6-inch substrates are currently under development. Owing to the rapid development of $Ga_2O_3$ bulk and epitaxy growth, device results have quickly followed. We look briefly into diamond and $Ga_2O_3$ semiconductor devices and epitaxy results that can be applied to harsh environments.

• Progress in Superconductivity and Cryogenics
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• v.9 no.3
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• pp.32-36
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• 2007

On the contrary of a conventional motor with very narrow air-gap. it is difficult to calculate the accurate magnetic field distribution and the performance of an air-cored superconducting motor by 2 dimensional analysis. which does not use high permeability material except outer machine shield. This paper aims to do analysis of magnetic field and force distribution from the 3 dimensional modelling of a 1MW class superconducting synchronous motor. Especially. the field coil composed of Bi-2223 high-temperature superconductor and the outer machine shield are modelled by finite element analysis software according to their structures and the self-inductance and Lorentz force are calculated based on the 3 dimensional magnetic field calculation. Moreover. the influence of an important parameter, synchronous reactance, has been analyzed on the machine performances such as voltage variation and output power.

• Journal of the Korean Society of Radiology
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• v.13 no.2
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• pp.175-183
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• 2019

Cerebral nervous system intervention has been reported frequently due to radiation exposure such as blistering of the skin, hair loss, and erythema due to prolonged procedures. By applying ergonomically manufactured Bismuth (atomic number 83; Bi) shield to endovascular treatment of cerebral aneurysms, we aimed to minimize radiation exposure of scalp and lens from medical radiation exposure. The measurement site was the posterior part of the head, bilateral temporal part, bilateral quadriceps part, nose part, and the measuring part was attached to the optically stimulated Luminescence dosimeter (OSLD) Before and after the use, the entrance surface dose was compared and analyzed. The average entrance surface dose of group A (unshield) was 92.44 mGy, and group B was measured at 67.55 mGy. The average decrease in Group B was 26.92% compared to Group A. The entrance surface dose mean of the occipital region was measured at 146.08 mGy B group at 103.23 mGy and decreased by an average of 29.32% in group B compared to group A. The average entrance surface dose of the bilateral temporal part was measured in group A at 101.90 mGy group B at 72.69 mGy and decreased by an average of 28.67% in group B compared to group A. The average entrance surface dose for bilateral quadriceps part was measured at 27.51 mGy group B at 21.39 mGy and averaged 22.26% less in group B than group A. It is believed that the use of bismuth shields will be an alternative to reducing radiation disturbance due to temporary hair loss and other stochastic effects that may occur after the endovascular treatment of cerebral aneurysms procedure.

• The Korea Journal of Herbology
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• v.28 no.3
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• pp.39-44
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• 2013

Objectives : The purpose of this study was to identify active fraction and components from antiplatelet Ulmi cortex extract. Methods : The 70% ethanol extract of Ulmi cortex was subjected to column chromatography over D101 resin and eluted with an 20% (W1), 30% (W2), 40% (W3), 50%(W4), 70% (W5), and 100% ethanol (W6) to yield 6 fractions. W6 was further fractioned and its active components were purified using semi-preparative HPLC. The isolated compounds were identified by MS and NMR, and their contents were simultaneously analyzed using HPLC/UV. Antiplatelet aggregation activities of the fractions and the compounds were evaluated using rat platelet-rich plasma in presence of collagen ($5{\mu}g/ml$), arachidonic acid (0.05 U/ml), or thrombin ($100{\mu}M$). Results : Among six fractions, W3 prominently inhibited platelet aggregation. At the concentration of $200{\mu}g/ml$, W3 strongly inhibited arachidonic acid- and collagen-induced platelet aggregations by 78.2% and 65.9%, respectivley, and weakly inhibited thrombin-inducded platelet aggregation by 32.6%. Catechin, epicatehin, and catechin-7-O-${\beta}$-D-glucopyranoside were isolated from W3 and their contents were revealed to be 15.1%, 0.87%, and 0.32%. Catechin and epicatechin at the concentrations of $100{\mu}M$ strongly inhibited collagen-induced platelet aggregation by 79.9% and 86.6%, respectively, but weakly inhibited arachidonic acid- and thrombin-induced platelet aggregations. Conclusions : A main active principle of anitplatelet Ulmi Cortex extract is W3 fraction, of which main active component is catechin considering its antiplatelet activity and content.