• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.321-322
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• 2007

In order to increase the cost effectiveness of solar cells, module production should be treated more comprehensively. Back contact cells offer distinct advantage in the interconnection of cells to modules. Thereby Mo thin film were prepared in order to clarify optimum conditions for growth of the thin film depending upon process, and then by changing a number of deposition conditions and substrate temperature conditions variously, structural and electrical characteristics were measured. For the manufacture of the Mo were vapor-deposited in the named order. Among them, Mo were vapor-deposited by using the sputtering method in consideration of their adhesive force to the substrate, and the DC power was controlled so that the composition of Mo, while the surface temperature having an effect on the quality of the thin film was changed from R.T$[^{\circ}C]$ to $200[^{\circ}C]$ at intervals of $50[^{\circ}C]$. Micro-structural studies were carried out by XRD (D/MAX-1200, Rigaku Co.) and SEM (JSM-5400, Jeol Co.). Electrical properties were measured by CMT-SR3000 Measurement System.

• 한국전기전자재료학회논문지
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• 제22권10호
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• pp.832-836
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• 2009

A piezoelectric ultrasonic scaler, usually used to remove the tartar out of teeth and to amputate the pubis, is a recently popular instrument for dental treatment due to its several merits such as small size, low-electric power, precision and low-cost. It has typically two parts of a tip and vibration system, which is also composed of head, piezoelectric elements and tail-mass. The scaler concentrates its displacement on tip and has commonly a resonance frequency at 25~30 kHz, and in order to improve the performance of the scaler, it is important to standardize the size of the vibration system without tip for high performance because scaler in quality differs according to several tips. In this study, a Finite Element Analysis (FEA) was utilized to optimize the structure of ultrasonic scaler in the vibration system. Consequently, this study revealed that influence of several tips on property were minimized and scaler showed good property at the resonance frequency of 28 kHz.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권2호
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• pp.421-441
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• 2021

Fruit detection in orchards is one of the most crucial tasks for designing the visual system of an automated harvesting robot. It is the first and foremost tool employed for tasks such as sorting, grading, harvesting, disease control, and yield estimation, etc. Efficient visual systems are crucial for designing an automated robot. However, conventional fruit detection methods always a trade-off with accuracy, real-time response, and extensibility. Therefore, an improved method is proposed based on coarse-to-fine multitask cascaded convolutional networks (MTCNN) with three aspects to enable the practical application. First, the architecture of Fruit-MTCNN was improved to increase its power to discriminate between objects and their backgrounds. Then, with a few manual labels and operations, synthetic images and labels were generated to increase the diversity and the number of image samples. Further, through the online hard example mining (OHEM) strategy during training, the detector retrained hard examples. Finally, the improved detector was tested for its performance that proved superior in predicted accuracy and retaining good performances on portability with the low time cost. Based on performance, it was concluded that the detector could be applied practically in the actual orchard environment.

• Nuclear Engineering and Technology
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• 제53권8호
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• pp.2556-2563
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• 2021

Metaheuristic algorithms can work well in solving or optimizing problems, especially those that require approximation or do not have a good analytical solution. Particle swarm optimization (PSO) is one of these algorithms. The response quality of these algorithms depends on the objective function and its regulated parameters. The nonlinear nature of the pressurized light-water nuclear reactor (PWR) dynamics is a significant target for PSO. The two-point kinetics model of this type of reactor is used because of fission products properties. The proportional-integral-derivative (PID) controller is intended to control the power level of the PWR at a short-time transient. The absolute error (IAE), integral of square error (ISE), integral of time-absolute error (ITAE), and integral of time-square error (ITSE) objective functions have been used as performance indexes to tune the PID gains with PSO. The optimization results with each of them are evaluated with the number of function evaluations (NFE). All performance indexes achieve good results with differences in the rate of over/under-shoot or convergence rate of the cost function, in the desired time domain.

• International Journal of Computer Science & Network Security
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• 제22권5호
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• pp.348-358
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• 2022

Software fault prediction is a method to compute fault in the software sections using software properties which helps to evaluate the quality of software in terms of cost and effort. Recently, several software fault detection techniques have been proposed to classifying faulty or non-faulty. However, for such a person, and most studies have shown the power of predictive errors in their own databases, the performance of the software is not consistent. In this paper, we propose a hybrid soft computing technique for SFP based on optimal feature extraction and classification (HST-SFP). First, we introduce the bat induced butterfly optimization (BBO) algorithm for optimal feature selection among multiple features which compute the most optimal features and remove unnecessary features. Second, we develop a layered recurrent neural network (L-RNN) based classifier for predict the software faults based on their features which enhance the detection accuracy. Finally, the proposed HST-SFP technique has the more effectiveness in some sophisticated technical terms that outperform databases of probability of detection, accuracy, probability of false alarms, precision, ROC, F measure and AUC.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.70-75
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• 2002

The penetration potential of TIG welding in one single run is limited, though the process itself generates high quality welds with good weld cosmetics. This is one of the main reasons, which has contributed to its development in high duty applications such as those encountered in aeronautical, aerospace, nuclear & power plant applications. For these applications, stainless steels, titanium k nickel based alloys are most often used. As these materials remain very sensible to weld heat input k atmospheric pollution, stringent processing conditions are imposed. For example welding of titanium alloys requires argon shielding of weld zone and for 5 mm thick plates multi-pass runs & filler additions are required. This multi-run operation not only raises the welding cost, but also increases defect risks. In recent years, extensive interest has been raised by the possibility to increase weld penetrations through flux applications & the process is designated ATIG-activated TIG, or FBTIG-flux bounded TIG. The improved welding performance of such flux assisted TIG is related to arc constriction and surface tension effects on weld pool. The research work by authors has lead to the formulation of welding fluxes for stainless steels k titanium alloys with TIG Process. These fluxes are now commercialized & some applications in industry have already been carried out. FBTIG for aluminum has been proposed with silica application for AC mode TIG welding. The paper highlights the fundamentals of flux role in TIG welding and illustrates some industrial applications.

• 인터넷정보학회논문지
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• 제8권5호
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• pp.133-140
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• 2007

최근 언제 어디서나 고품질의 인터넷 서비스 이용에 대한 필요성이 증가함에 따라, 인터넷 또는 셀룰러 망과 같은 기반 망과 연동된 하이브리드 애드 혹 네트워크에 대한 연구가 중요해지고 있다. 이러한 통합 네트워크는 홈 네트워크, 텔레매틱스, 센서 네트워크 분야 등에서 사용자 요구에 부합하는 다양한 종류의 서비스 제공이 가능해진다. 그러나 무선 이동 네트워크에서 불안정한 링크에 의한 전송 거리와 전송 대역폭 및 이동 노드의 배터리 제약은 대용량의 실시간 데이터 처리를 요구하는 서비스의 원활한 제공을 어렵게 만든다. 따라서 본 논문에서는 기반 망에서 제공하는 인프라를 활용하여 에너지 효율성을 고려한 클러스터 기반의 계층적 라우팅 기법을 제안한다. 인덱스 기반의 브로드캐스팅 기법을 적용한 경로 전달 모델을 통해 노드가 필요한 정보만을 선택적으로 청취함으로써 불필요한 에너지 손실을 줄인다. 또한, 경로 탐색 및 유지비용과 경로 설정에 필요한 지연시간을 줄였다.

• 한국산학기술학회논문지
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• 제12권3호
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• pp.1302-1307
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• 2011

본 논문은 코일 제작 시 고려사항인 1, 2차측 코일 인덕턴스, 턴수, 크기, 두께, 차폐지 등을 고려하여 리쯔 와이어로 나선형 코일을 제작하는데 이때 반자동화 권선기를 사용하게 된다. 1, 2차측 코일 사양을 정하여 코일을 제작할 때 다양한 사양의 리쯔 와이어와 나선형 코일을 필요로 하게 되는데, 이때 제작 비용, 기간, 제작 시 발생하는 불량 등으로 인해 코일 샘플 제작에 어려움이 발생하고 원하는 사양의 코일 품질 관리에도 어려움이 생기게 된다. 이를 개선하기 위해 2차측의 정류부를 개선함으로써 코일 설계 및 제작 시 다양한 코일 제작 사양의 범위를 좀더 포괄적으로 할 수 있으며 제작 시 발생하는 비용을 줄이고, 기간 단축 및 코일의 품질 관리를 개선하고자 한다.

• 한국건설순환자원학회논문집
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• 제5권3호
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• pp.305-312
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• 2017

본 연구에서는 국내 화력발전소에서 발생되고 있는 산업부산물을 활용하여 아스팔트 콘크리트용 채움재를 개발 및 혼합물에 적용하여 함량에 따른 특성 및 소성변형 저항성에 미치는 영향을 관찰하였다. 실험결과 석탄회 기반 채움재를 사용할 경우 최적아스팔트함량(OAC)는 기존 채움재 대비 0.1% 낮은 값을 나타내었다. 도출된 최적아스팔트함량에서 채움재 함량에 따른 간접인장강도 및 인장강도비 측정 결과 함량 증가에 따라 높은 성능을 발현하였고, 2.0% 이상의 함량에서 국내 단체표준 품질관리 기준 각 0.8 이상과 0.75 이상을 만족하는 결과를 얻을 수 있었다. 동적안정도는 채움재 2.5%의 함량에서 가장 높은 저항성을 나타내었으며, 함량이 2.5%를 넘어설 때 오히려 성능발현이 저하되는 결과를 나타내었다. 과도한 채움재의 혼입은 상대적으로 아스팔트 함량이 감소되기 때문에 취성파괴를 유발할 수 있으므로 최적의 채움재/아스팔트 의 비율을 찾아 적용하는 방안이 필요할 것으로 판단된다.

• 한국군사과학기술학회지
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• 제2권1호
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• pp.38-60
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• 1999

The main objective of this study is systemization of the technique of ROC quantification and optimization of baseline design by applying CE principle to the acquisition process of a weapon system. QFD and TOA techniques can be employed to a good working example of the conceptual design of a future main battle tank. In this paper, Product Planning Phase, the first phase of four QFD phases, is deployed in terms of eight steps including customer requirements and final product control characteristics. TOA is carried out considering only combat weight. In order to perform combat weight analysis and performance TOA, Preliminary Configuration Synthesis Methodology is used. Preliminary Configuration Synthesis Methodology employs the method of least squares and described linear equations of weight interrelation equation for each component of tank. As a result of QFD based upon the ROC, it was cleared that armor piercing power, main armament, type of ammunition, cruising range, combat weight, armor protection, power loading, threat detection and cost are primary factors influencing design and that combat weight is the most dominant one. The results of TOA based on the combat weight constraint show that 5100 lb reduction was required to satisfy the ROC. The baseline design of a future main battle tank is illustrated with assumption that all phases of QFD are employed to development and production process of subsystems, components, and parts of main battle tank. TOA is applied in iterative process between initial baseline design and ROC. The detailed design of each component is illustrated for a future main battle tank.