• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.561-563
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• 2005

From the IF (Intermediated Frequency) loop-back test, BER (Bit Error Rate) degradation of processed data, HRIT (High Rate Information Transmission), is estimated by proposed measurement configuration. The specific parameters, likely data rate, FEC (Forward Error Correction), and modulation method, are based on the outcomes of SRR (System Requirements Review) which was held on 13-14 June 2005, in Toulouse. The proposed measurement procedure is that combined 70MHz modulated signal and noise is connected to the spectrum analyzer and receiver. The former measures the C/No (Carrier to Noise density ratio) and the latter estimates BER of FEC decoded data. Implementation loss can be obtained by subtracting measured BER from calculated BER which is also subtracted data rate from measured C/No. This test procedure is very simple and can be applied to assess the implementation loss of dedicated receiver for HRIT in the future.

• 설비공학논문집
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• 제25권1호
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• pp.37-42
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• 2013

Double pipe system in which PB pipe is inserted in CD pipe buried in the concrete slab is widely used for cold and hot water supplies in apartment housings. The system, however becomes complicated and the overlaying pipes in the concrete slab weaken the compressive strength of the slab. Also, insufficient insulation increases energy loss. In this work, the problems of the double pipe system are studied and plans A, B, and C are suggested for improvement. In terms of compressive strength of the concrete slab, plan A(total pipe length 73 m) was the weakest and plan B(2 m) was the strongest. Energy loss of plan A was the largest with 558.9 W and plan B was the lowest with 220.7 W. However, considering the combined effect of strength and heat loss, plan C becomes the best choice, which retains the advantage of the double pipe system.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1229-1239
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• 2014

Optimal Distributed Generation (DG) output and reconfiguration are among the well accepted approach to reduce power loss in a distribution network. In the past, most of the researchers employed optimal DG output and reconfiguration separately. In this work, a simultaneous DG output and reconfiguration analysis is proposed to maximize power loss reduction. The impact of the separated analysis and simultaneous analysis are investigated. The test result on the 33 bus distribution network with 3 units of DG operated in PV mode showed the simultaneous analysis gave the lowest power loss (global optimal) and faster results compared to other combined methods. All the analyses for optimizing the DG as well as reconfiguration are used the Artificial Bee Colony Optimization technique.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제11권1호
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• pp.1-10
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• 2022

완전연결신경망은 다양한 문제를 해결하는데 널리 사용되고 있다. 완전연결신경망에서 비선형활성함수는 선형변환 값을 비선형 변환하여 출력하는 함수로써 비선형 문제를 해결하는데 중요한 역할을 하며 다양한 비선형활성함수들이 연구되었다. 본 연구에서는 완전연결신경망의 성능을 향상시킬 수 있는 결합된 파라메트릭 활성함수를 제안한다. 결합된 파라메트릭 활성함수는 간단히 파라메트릭 활성함수들을 더함으로써 만들어낼 수 있다. 파라메트릭 활성함수는 입력데이터에 따라 활성함수의 크기와 위치를 변환시키는 파라미터를 도입하여 손실함수를 최소화하는 방향으로 최적화할 수 있는 함수이다. 파라메트릭 활성함수들을 결합함으로써 더욱 다양한 비선형간격을 만들어낼 수 있으며 손실함수를 최소화하는 방향으로 파라메트릭 활성함수들의 파라미터를 최적화할 수 있다. MNIST 분류문제와 Fashion MNIST 분류문제를 통하여 결합된 파라메트릭 활성함수의 성능을 실험하였고 그 결과 기존에 사용되는 비선형활성함수, 파라메트릭 활성함수보다 우수한 성능을 가짐을 확인하였다.

• 대한기계학회논문집
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• 제15권6호
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• pp.2037-2047
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• 1991

본 연구에서는 재료 결정격자의 기본단위나 결정립의 형상등 가장 기본적인 형태가 6각형이라는 점에 착안하여 취성재료의 파손모델로 부재들의 결손을 이용하는 결손확률모델을 제안하여 부재결손에 따른 각각의 파손 해석모델과 결손확률을 구한다. 그리고 비결손모델에서 구한 기본인장하중을 기초로 하여 해석하고자 하는 하중하에서 각각의 파손해석모델을 모델링하여 유한요소법으로 부재결손에 따른 요소중심에서의 최대주응력을 구하여 이론극한인장강도와의 비와 결손확률로 취성재료의 파손확률을 구한다. 또한 취성정도에 따른 균열길이에 대한 치수 매개변수를 구함으로써 재료강 도 연구에 기초가 되게 한다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권6호
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• pp.440-448
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• 2012

Purpose: The purpose of this study was to evaluate marginal bone loss of the alveolar crest on implants with or without guided bone regeneration and variables that have influenced. Methods: The clinical evaluation were performed for survival rate and marginal bone loss of 161 endosseous implants installed with guided bone regeneration (GBR) in 83 patients from September 2009 to October 2010 in relation to sex and age of patients, position of implant, implant system, length and diameter of implant. Study group (n=42) implant with GBR procedure, control group (n=41) implant without GBR technique. Simultaneous GBR approach using resorbable membranes combined with autogenous bone graft or freeze-dried bone allograft or combination. Radiographic examinations were conducted at healing abutment connection and latest visit. Marginal bone level was measured. Results: Mean marginal bone loss was 0.73 mm in study group, 0.63 mm in control group. Implants in maxillary anterior area (1.21 mm) were statistically significant in study group (P<0.05), maxillary posterior area (0.81 mm) in control group (P<0.05). Mean marginal bone loss 1.47 mm for implants with diameter 3.4 mm, 0.83 mm for implants of control group with diameter 4.0 mm (P<0.05). Some graft materials showed an increased marginal bone loss but no statistically significant influence of sex, implant type or length. Conclusion: According to these findings, this study demonstrated the amount of marginal bone loss around implant has maintained a relative stable during follow-up periods. We conclude that implants with GBR had similar survival rate and crestal bone level compared with implants in native bone.

• 대한치과교정학회지
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• 제43권2호
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• pp.101-109
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• 2013

Objective: To evaluate the efficiency of the Frog appliance (FA) alone or in combination with headgear for distalizing the maxillary molars. Methods: Fifty patients (25 males and 25 females) aged 12.6 - 16.7 years who received treatment for Class II malocclusion at the Orthodontic Clinic of Al-Baath University were selected for this study and randomly divided into 2 equal groups. Maxillary molar distalization was achieved using the FA alone (group 1) or a combination of the FA with high-pull headgear worn at night (group 2). Lateral cephalograms were obtained before and after treatment. Results: The maxillary molars moved distally by 5.51 and 5.93 mm in groups 1 and 2, respectively. Distal movements were associated with axial tipping by $4.96^{\circ}$ and $1.25^{\circ}$, and with loss of anchorage by mesial movement of the second maxillary premolars by 2.70 and 0.90 mm in groups 1 and 2, respectively. The combined use of the FA and nighttime high-pull headgear decreased the distalization time and improved the ratio of maxillary molar distalization movement relative to the overall opening space between the first maxillary molars and second premolars. Conclusions: The FA can effectively distalize the maxillary molars, this distalization associates with some unfavorable changes. Nighttime use of high-pull headgear combined with the FA can reduce these unfavorable changes and improve treatment outcomes.

• 신재생에너지
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• 제7권4호
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• pp.37-41
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• 2011

This paper presents a Combined solar-wave Power Generation (CPG) concept that the CPG unit is maintained as buoyant at the level of sea water and it is also supported by a submerged tunnel, with the aim of supplying emergency electric power during the station blackout events of nuclear power plants. The CPG concept has been motivated from the 2011 Fukushima-Daiichi Accidents due to the loss of both offsite AC power and emergency diesel power caused by natural hazards such as earthquake and tsunami. The CPG is conceptualized by applying different types and different sites for emergency power generation, in order to reduce common cause failures of emergency power suppliers due to natural hazards. Thus, the CPG can provide a new mean for supplying emergency electric power during station blackout events of nuclear power plants. For this application, the CPG requirements are described with a typical configuration at the ocean side of a submerged tunnel.

• 대한기계학회논문집A
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• 제26권7호
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• pp.1416-1425
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• 2002

In this study, the effects of combined environmental factors on mechanical and thermal analysis properties of graphite/epoxy composites were evaluated by the use of an accelerated aging test. Environmental factors such as temperature, moisture. and ultraviolet were considered. A xenon-arc lamp was utilized for ultraviolet light. and exposure times of up to 3000 hours were applied. Several types of specimens - tensile. bending, and shear specimens those are transverse to the fiber direction, and bending specimens those are parallel to the tiber direction - were used to investigate the effects of environmental factors on mechanical properties of the composites. Also, glass transition temperature, storage shear modulus, loss shear modulus, and tan ${\delta}$ were measured as a function of exposure times through a dynamic mechanical analyzer. In addition. a suitable testing method for determining the effect of environmental factors on mechanical properties is suggested by comparing the results from using two different types of strain measuring sensors. Finally, composite surfaces exposed to environmental factors were examined using a scanning electron microscope.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.904-909
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• 2009

In this paper, a rolling piston rotary compressor having a combined vane and roller unit has been introduced. In a conventional rotary compressor, sliding motion takes place between the vane nose and roller. By combining the vane and the roller in one unit, gas leakage through a clearance between the vane nose and the roller can be eliminated, and the frictional loss between them can also be reduced to almost nought. Compressor model with the combined vane and roller has been fabricated and tested in a compressor calorimeter and computer simulation program has been developed to confirm merits of the new mechanism. In a test, cooling capacity has been found to be increased by 1.4%, and the compressor input decreased by 0.3%, resulting in 1.7% increased in EER. Simulation program confirmed the calorimeter test results and the merits of the new model as mentioned above.