• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 추계 학술발표회논문집
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• pp.481-488
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• 2003

A fluid-structure-isolator interaction program was developed in this study. The behavior of liquid regions are simulated by the boundary element method, and then the technique of analyzing the free surface motion in time domain is developed by using the nonlinear free surface boundary condition(NFBC) and the condition of interface between the structure and the fluid. Structure regions are modeled by the finite element method. In order to construct the governing equation of the fluid structure interaction(FSI)problem in time domain, the finite elements for a structure and boundary elements for liquid are coupled using the equilibrium condition, the compatibility condition and NFBC. The isolator is simulated by equation proposedin 3D Basis Me. In order to verify the validity and the applicability of the developed fluid- structure -Isolator interaction program, The horizontal forced vibration analysis was performed. The applicability of the developed method is verified through the artificial seismic analysis of real size liquid storage tank.

• 대한토목학회논문집
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• 제35권1호
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• pp.101-110
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• 2015

최근 Hsu는 전단시험장치를 이용해 순수전단이 작용하는 9개 RC패널요소의 전단시험을 수행하였다(ACI 1997). 최신 트러스모델(수정압축장이론, 회전각연성트러스모델)은 평형조건과 적합조건 그리고 2축 상태에서 RC 막판넬의 연성 응력-변형률 관계를 이용하여 2중 루프의 시행착오방법으로 복잡한 비선형해석을 수행하고 있다. 본 연구는 스트럿과 타이의 파괴기준에 기반한 개선된 모어변형적합방법을 사용해 효율적인 알고리즘을 제안하였고, 이 알고리즘을 이용하여 Hsu가 실험한 전단이력 해석을 빠른 수렴속도로 개선한 것이다. 해석결과에 의하면 전단변형률 증폭상태의 전단변형에너지는 주압축 응력-변형률에 크게 지배받는 것으로 나타났다.

• The Plant Pathology Journal
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• 제15권1호
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• pp.53-56
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• 1999

Fifty-three isolates of Fusarium graminearum were obtained from corn and barley samples in several provinces of Korea. Gas chromatography-mass spectrometric analysis of trichothecenes produced by these isolates revealed that 37 and 16 isolates were nivalenol (NIV)- and deoxynivalenol (DON)-chemotypes, respectively. Two hundred and seventy-five nitrate-nonutilizing (nit) mutants were obtained from the isolates. Of these mutants, 187 were identified as nit1, nit3, or NitM, but 88 could not be identified as one of these classes. The highest frequency of nit mutant was nit1 (65%), followed by nit3 (20%) and NitM (15%). Higher frequency of NitM was observed in DON-chemotypes than in NIV-chemotypes. The mutants were used for vegetative compatibility group (VCG) analysis by examining heterokaryosis using complementary mutant pairs. No heterokaryon formation was observed among all 1,248 pairwise combinations, suggesting that all isolates tested belong to different VCGs. Higher frequency of self-incompatibility was observed in NIV-chemotypes than in DON-chemotypes. These results suggest that the like-lihood of asexual genetic recombination may be very low I F. graminearum under the field condition.

• 한국공간구조학회논문집
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• 제17권4호
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• pp.149-157
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• 2017

An innovative analysis method is proposed in this paper for the determination of ultimate resistance of prestressed concrete beams. The proposed method can be applied to simply supported or continuous beams in a unified manner whether structure and external loads are symmetric or not. Through the iterative nonlinear strain compatibility solutions, this method can also be applied to the non-prismatic section/un-symmetrical composite structures under moving load. The conventional studies have used the failure criteria when the strain of concrete reaches 0.003. However compared with bonded case, the value of strain in the reinforcement is much smaller than bonded case, thus, unbonded prestressed cases show compressive failure mode. It is shown that the proposed method gives acceptable results within 5% error compared with the prior experimental results. It can be shown that the proposed method can reach the solution much faster than typical three-dimensional finite element analysis for the same problem. This method is applicable to the existing unbonded prestressed members where deterioration has occurred leading to the reduced ultimate resistance or safety. In all, the proposed procedure can be applied to the design and analysis of newly constructed structures, as well as the risk assessment of rehabilitated structures.

• 산경연구논집
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• 제9권11호
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• pp.17-24
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• 2018

Purpose - The portability, functionality, and convenience of smart phones are constantly updated. With the rapid popularization of users of mobile terminals, Xiaomi is also developing rapidly. In February 2015, the users of Xiaomi exceeded 100 million people. As a transnational industry, Xiaomi has developed rapidly in not only China but also Korea. However, through the literature review, there is no radmissible study on the Xiaomi mobile telephones in the Korean market, so it is necessary to study the Xiaomi mobile phones in Korean market. Research design, data, and methodology - Figure analysis of data and social science analytical software of IBM SPSS AMOS 23.0 and IBM Statistics 23.0 were used for all the data researched. Results - First, the innovative diffusion temperament and the compatibility of Xiaomi have positive impacts on achievement expectations and effort expectations. Second, the innovative diffusion temperament and the complexity of Xiaomi have negative impacts on achievement expectations and effort expectations. Third, the innovative diffusion characteristics and the relative superiority of Xiaomi have positive impacts on achievement expectations and effort expectations. Conclusions - Through the analysis of the prior study, the innovation acceptance characteristics consist of compatibility, complexity, relative superiority, observation possibility, and the attempt possibility; the technical acceptance characteristics consist of achievement expectations, effort expectations, social influence, promotion condition, the study conducts relevant research on the continued use intention and analyze the hypothesis of research model.

• Journal of Positioning, Navigation, and Timing
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• 제12권2호
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• pp.177-184
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• 2023

In order to reserve frequency bands for stable operation of the Korean Positioning System (KPS), it must be demonstrated that the impact of interference caused by KPS on other services operating in the same bands is tolerable. The International Telecommunication Union (ITU) provides the radio regulations and a compatibility assessment methodology for the coexistence of different services in limited frequency resources. The purpose of this paper is to investigate the radio regulations regarding the compatibility issues between the KPS and other services sharing the same frequency bands. The results of the investigation show that the RNSS system can be operated in the L5-band under the condition that the Power Flux Density (PFD) and Aggregated Equivalent PFD (AEPFD) thresholds specified in the radio regulations are met. In addition, the ITU recommends that the interference-to-noise ratio (INR) protection criteria be met to prevent degradation of the performance of radar systems operating in the L2/L6-band. In the case of the S-band, coordination of allocations for RDSS space stations with respect to terrestrial services is not required if the PFD does not exceed regulated thresholds regulated by ITU.

• 설비공학논문집
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• 제6권4호
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• pp.439-452
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• 1994

One of the chlorofluorocarbon compounds. R-12 deplete atmospheric ozone. It leads to international agreement to reduce CFC production. R-134a has similar thermodynamic properties to CFC-12. It has zero ODP(Ozone Depletion Potential). This Paper focuses on the lubricating oils for using with R-134a PAGs(Polyalkylene Glycol's) and esters are primary lubricants that are now being tested for use with R-134a Because of extreme polarity of R-134a. there are many problems in the selection of lubricating oil. This investigation analyzes compressor working conditions and calculates wear parts friction for simulation testing. Miscibility and material compatibility is proved by sealed glass tests. Friction was tested on the closed type pin on disk wear tester. This equipment simulates actual refrigerating compressor. Environment controlled test made more reliable result than field test Conventional oils(mineral oils, Alkylbenzene, PAO(Polyalpha Olefin) are immiscible with R-134a. PAGs and ester oils are miscible with R-134a. Friction coefficient is similar to conventional system(mineral oil/R-12 systems) at operating condition. At start & stop condition, PAGs/R-134a system has high friction coefficient. It provide reliable result on the lubricity, miscibility, material compatibility of R-134a with these new lubricants. It suggests proper selection of refrigeration oil that may improve compressor durability of performance.

• 한국자기학회지
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• 제22권6호
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• pp.210-215
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• 2012

단층형 전자파 흡수체의 흡수 성능은 입사파의 반사 손실(return loss)이 최대가 되는 두께 정합 조건 및 주파수 정합 조건에서 최적화 된다. 본 연구에서는 재료의 복소 투자율과 복소 유전율에 의존하는 전송선 이론을 적용하여 광대역 흡수체의 정합 조건을 계산하였다. 그 결과 주파수에 따른 복소 투자율 감소 특성이 두께 정합 조건을 광대역으로 확대하는 효과를 지니기 때문에 광대역 전자파 흡수체에 자성 재료가 이용될 수 있다는 것을 알 수 있었다. 따라서 향후 확대될 EMC(Electromagnetic compatibility) 규격을 대비한 차세대 광대역 전자파 흡수체를 만들기 위하여 현재 사용되고 있는 NiZn 페라이트 소결체 보다 포화 자화량이 크고 유전율 값이 작은 자성 재료들을 사용하여야 한다는 것을 보였다.

• 한국IT서비스학회지
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• 제17권4호
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• pp.85-100
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• 2018

In this study, we formulated rational criteria to efficiently provide traffic information services via a crafted approach. By utilizing this, we presented a detailed traffic information service providing method that can overcome the limitations of existing link unit information provision system. Three methodologies such as user survey, data mining, and KHCM (Korea Highway Capacity Manual) utilization method were applied to formulate a rational expression standard for traffic information service. Each method was designed to establish a quantitative criterion for various traffic conditions and to enable user-oriented traffic information service in consideration of the traffic principal/compatibility. Considering the results of each methodological analysis in a comprehensive manner, the basic expression standards for traffic information service was formulated. Then we presented improvements such as traffic condition step by road, speed range of traffic condition, expression term of traffic condition and so on. In order to complement the problems of the information provision system of the existing link unit based on the derived improvement criterion, we presented the detailed traffic information service provision method by using the traffic speed data of the second order. And we applied this to the two links of Daegu city. The method presented in this research can improve the quality of traffic information service. Not only it can be used for various fields such as optimal route search, traffic safety service and so on.

• Corrosion Science and Technology
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• 제8권2호
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• pp.68-73
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• 2009

An evaluation of underwater - repair coating materials was based on the premise that defective areas of the existent epoxy coating such as blistering and cracking will be repaired on spot under submerged condition. Tests include the clarification as to whether they are compatible between as-built coating and new repair coating on each concrete specimen. Candidate coating materials for repair were tested in a laboratory to scrutinize their suitability to perform the needed function satisfactorily. The qualification tests performed are as a minimum as follows: Integrated radiation tolerance test, chemical resistance test (submerged condition in deionized water), hardness test and adhesion test of the repair materials. The proper repair coating materials were selected and approved from this test results.