• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.286-287
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• 2006

In this paper, an experiment result on overload of distribution transformer was arranged by top oil temperature depending on capacity and time. This result shows the definition on overload of transformer is different by some factors such as ambient temperature and immediate load. In other words, increased temperature in range of regulation(50K) has time to spare even if the condition of transformer is overload. The algorithm presented in this paper is based on the international standard (IEEE std C57.91), and the safety of switchboard is diagnosed by this aspect mentioned on overload of transformer.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.4
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• pp.952-960
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• 1996

In this paper, a new overload control scheme is proposed for a control system in ATM switching system. The proposed control scheme includes a counter that conunts the number of accepted calls and is decreased at cach D time interval. In overload condition of call processor, the control scheme detects over load condition when the counter value reaches a certain threshold value. Under overload condition, processor utilization is measured and the value of the D is updataed according to the difference between measured processor utilization and target utilization. A new call is accepted accepted only if the value of the counter is less than the threshold value. In overflow condition of cell traffic, accept probability of new call is reduced exponetially according to the elapsed time. The results of simulation show that the proposed overload contorl scheme maintains the target utilization very well under the various processor overload conditions and reduces the cell loss probability under the cell overflow conditions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.4
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• pp.662-670
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• 2001

We evaluate the effectiveness and validity of J(sub)e, which comprehensively describes the effects of specimen geometry and loading type, in predicting the fatigue life of auto seat belt anchor panel. We first simplify the heat affected zone model to reduce the number of finite elements. We then establish finite element models reflecting the actual overload behavior of 3 types of seat belt anchor specimens. Using finite element models elaborately established, we obtain the effective crack driving parameter J(sub)e composed of its ductility-dependent modal components. It is confirmed that the J(sub)e concept successfully predicts the fatigue life of multi-spot welded panel structures represented by auto seat belt anchors here.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1189-1190
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• 2006

본 논문은 연료전지와 플라이윌 저장 시스템용을 결합한 복합전원으로 하는 연료전지 발전 시스템의 전력변환장치 연구에 관한 것이다. 이를 위한 전력변환장치는 연료전지로부터 저전압을 상승시키기 고조파 DC-DC 컨버터 이를 안정된 교류전원으로 변환하기 위한 DC-AC 인버터 및 플라이휠에 에너지 회생과 재생하기 위한 DC-AC 컨버터로 구성된다. 본 연구에서는 기존의 UPS 시스템은 AC 발전기 및 배터리를 백업 전원으로 사용하는데 맡은 유해 물질을 발생시키지만, 이 시스템을 사용하면 환경 오염, 높은 효율 및 대용량에 적합하다. 또한, 시뮬레이션을 통하여 연료전지 발전 시스템에 과부하시 안정하게 출력 성능을 가지도록 Fly-Wheel 시스템을 적용한 모의실험 결과를 제시한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.311-312
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• 2008

$RuO_2$ 계열의 후막재료를 사용한 저항의 신뢰성시험을 실시하고 주요 고장 메커니즘을 확인하였다. 사용된 소자의 기판은 AlN 세라믹 기판이며, 후막재료로 $RuO_2$ paste를 프린팅하고 소결시킨 구조의 고주파용 저항(RF Termination)이다. 주요 고장 메커니즘은 후막(Thick Film)의 특성변화, 기판의 특성변화, 전극-후막 간의 접촉특성변화, Trimming 부위의 열화, 열팽창계수 차이에 의한 기계적 파손 등으로 알려져 있으며, 본 실험에서는 고장모드 분석을 위해 과부하시험, 고온동작시험 등을 포함한 신뢰성 환경시험과 수명시험을 실시하였다. 각 시험 결과 수명시험 후 전극-후막 간의 접합부 파괴가 관찰되었고, 열충격 시험 결과 후막의 crack이 관찰되었다.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.945-946
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• 2014

국제 해상무역에 있어서 수출입 화물이 송하주로부터 수하주에게 인도되기까지 아무리 안전한 포장의 화물이라 할지라도 선박에 의한 해상운송 도중에 외부 포장의 파손이나 변질, 손상, 도난 등의 사고가 빌생할 수 있으며 과부족/착오 선적, 하역 중의 화물사고 등의 문제점을 예방/처리를 위해 검수라는 서비스가 이루어진다. 검수업무는 전문 검수사에 의하여 화물의 상태확인 등을 검수용지에 수기로 기록하게 되어있다. 인력에 의한 이러한 수작업은 문서의 집계, 처리, 분석 등에 오류와 비효율을 발생시키고 인건비 상승에 따른 물류비용 절감에 어려움을 주고 있다. 본 논문에서 제안하는 CCTV 검수 시스템을 이용하면 이러한 문제점들을 극복할 수 있을 것이다.

• The Transactions of the Korea Information Processing Society
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• v.1 no.4
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• pp.502-510
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• 1994

CDMA technique has been largely focused for Wireless Data Communication and Personal Communication Network. ALOHA protocol also has been proven to be effective for Packet Radio Radio Network regardless of low throughput due to channel collisions. In this paper, we evaluate the performance of MS-CDMA-ALOHA (Mini-Slotted-CDMA-ALOHA) system, by analytic and simulation method. The superiority of the MS-CDMA-ALOHA system over conventional Slotted ALOHA and Slotted-CDMA-ALOHA systems are clearly demonstrated for throughput, delay and stability performances.

• Journal of Biosystems Engineering
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• v.6 no.2
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• pp.9-19
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• 1982

The aim of this study was to improve the startability of the diesel engine at low temperature. The specific objective was to determine the optimum type of precombustion chamber. The eight different types of precombustion chamber and two different types of the cylinder head were designed and tested by $2^7$ factorial experiments with four replications. The lowest starting temperature for first operation, the maximum output, and the specific fuel consumption at full load and overload were checked and analyzed. The results of the study are summarized as follows; 1. The lowest starting temperature was lowered as much as $2.4^{\circ}C$ and the maximum output was increased as much as 0.3 ps with respect to the difference in the relative angle of the main passageway against the piston head from 20 degree to 18 degree. 2. The lowest starting temperature and the maximum out-put were lowered as much as $3.3^{\circ}C$ and 0.3 ps respectively with respect to the difference in the angle of the cylinder head groove from 20 degree to 18 degree. 3. The lowest starting temperature and the maximum out put were lowered as much as $2^{\circ}C$ and 0.2 ps respectively with respect to the difference in the length of the precombustion chamber from 17.5 mm to 15.5mm. 4. There was no significant difference in the startability but the maximum output was increased as much as 0.2 ps with respect to the difference in the diameter of the main passageway from 4.8mm to 4.5mm. 5. The lowest starting temperature was obtained under the condition at 47 degree in the angle of the main passageway and at 18 degree in the angle of the cylinder head groove. The maximum output and the minimum specific fuel consumption was obtained under the condition at 4.5mm in the diameter of the main passageway and at 17.5mm in the length of the precombustion chamber. 6. The angle of the cylinder head groove and the main passageway appeared to the major factors affecting the startability significantly. The interaction between the diameter of the main pass ageway and the length of the precombustion chamber had an significant influence on the maximum output. So it would be recommended to study further on the interaction between two factors mentioned above by expanding their levels. 7. The optimum condition suggested by this study could lower the starting temperature by $6^{\circ}C$ compared to the conventional precombustion chambers.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.4
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• pp.131-144
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• 2015

This research proposes a prototype for visualizing radar rainfall data using the unity 3D engine. The mashup of radar data with topographic information is necessary for the 3D visualization of the radar data with high quality. However, the mashup of a huge amount of radar data and topographic data causes the overload of data processing and low quality of the visualization results. This research utilized the Unitiy 3D engine, a widely used engine in the game industry, for visualizing the 3D topographic data such as the satellite imagery/the DEM(Digital Elevation Model) and radar rainfall data. The satellite image segmentation technique and the image texture layer mashup technique are employed to construct the 3D visualization system prototype based on the topographic information. The developed protype will be applied to the disaster-prevention works by providing the radar rainfall data with the 3D visualization based on the topographic information.

• Journal of Digital Convergence
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• v.13 no.4
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• pp.101-114
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• 2015

The purpose of this study is first to understand agent's turnover from both academic and perspectives. Then we suggest convergence of smart work paradigm and supervisor's support as the relieving factors of turnover, The research model of this study is based upon reviews of turnover literature, the smart work and supervisor's support as moderating variables from which research hypotheses were derived. The data came from the survey from financial sector agents such as banking, insurance, and others. The analyses has been done by SPSS 20.0, We used multiple regressions to test the effects of the tested variables on the dependent variable, job satisfaction. The results of this study find significant relations of smart work and supervisor's supports in relations to personal and job-related turnover. The implication is smart work and supervisor's supports play significant role in increasing job satisfactions. Major finding is too much supervisor's supports ignoring agent's situations may bring reverse effects on relieving turnover.