• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 춘계학술발표대회
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• pp.15.2-15.2
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• 2009

Manufacturing of printed electronics using printing technology has begun to get into the hot issue in many ways due to the low cost effectiveness to existing semi-conductor process. This technology with both low cost and high productivity, can be applied in the production of organic thin film transistor (OTFT), solar cell, radio frequency identification (RFID) tag, printed battery, E-paper, touch screen panel, black matrix for liquid crystal display (LCD), flexible display, and so forth. The emerging technology to manufacture the products in mass production is roll-to-roll printing technology which is a manufacturing method by printings of multi-layered patterns composed of semi-conductive, dielectric and conductive layers. In contrary to the conventional printing machines in which printing precision is about $50~100{\mu}m$, the printing machines for printed electronics should have a precision under $30{\mu}m$. In general, in order to implement printed electronics, narrow width and gap printing, register of multi-layer printing by several printing units, and printing accuracy of under $30{\mu}m$ are all required. We developed the roll-to-roll printing equipment used for printed electronics, which is composed of un-winder, re-winder, tension measurement system, feeding units, dancer systems, guide unit, printing unit, vision system, dryer units, and various auxiliary devices. The equipment is designed based on cantilever type in which all rollers except printing ones have cantilever types, which could give more accurate machine precision as well as convenience for changing rollers and observing the process.

• 전력전자학회논문지
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• 제21권2호
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• pp.144-149
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• 2016

This paper presents a power control method of high-speed single-phase BLDC motor. Most electric appliances require a power factor corrector (PFC) to mitigate grid current harmonics. However, the reactive components and power semiconductors in the PFC increase system cost and dimension. In this paper, a new motor drive system for a high-speed single-phase BLDC motor is proposed, which can decrease grid current harmonics without PFC by directly manipulating motor power and eliminating bulky electrolytic dc-link capacitor. Given that the proposed motor power control method does not require motor current controller, no current sensor is necessary. Moreover, the proposed algorithms can be easily implemented using a low-cost micro-controller. The effectiveness of the proposed power control method is verified by experiments.

• Journal of Power Electronics
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• 제18권4호
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• pp.1086-1098
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• 2018

This study presents a new sensorless commutation method for brushless direct current motors to replace Hall sensor signals with virtual Hall signals. The importance of the proposed method lies in the simultaneous elimination of the phase shifter and the low-pass filters, which makes the method simple and cost-effective. The method removes high ripple switching noises from motor terminals, thereby decreasing motor losses. The proposed method utilizes unfiltered line voltages with notches caused by current commutation. Hence, specific sign signals are defined to compensate for the effects of commutation noise. The proposed method is free from phase delay that originates from low-pass filters. The method directly produces virtual Hall signals, and thus, it can be interfaced with low-cost commercial commutation integrated circuits based on Hall sensors. Simulation and experimental results show the effectiveness and validity of the proposed method.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.230-234
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• 2009

It is significant technique to increase competitiveness that solar cells have a high energy conversion efficiency and cost effectiveness. When making high efficiency crystalline Si solar cells, evaporated Ti/Pd/Ag contact system is widely used in order to reduce the electrical resistance of the contact fingers. However, the evaporation process is no applicable to mass production because high vacuum is needed. Furthermore, those metals are too expensive to be applied for terrestrial applications. Ni/Cu/Ag contact system of silicon solar cells offers a relatively inexpensive method of making electrical contact. Ni silicide formation is one of the indispensable techniques for Ni/Cu/Ag contact sytem. Ni was electroless plated on the front grid pattern, After Ni electroless plating, the cells were annealed by RTP(Rapid Thermal Process). Ni silicide(NiSi) has certain advantages over Ti silicide($TiSi_2$), lower temperature anneal, one step anneal, low resistivity, low silicon consumption, low film stress, absence of reaction between the annealing ambient. Ni/Cu/Ag metallization scheme is an important process in the direction of cost reduction for solar cells of high efficiency. In this article we shall report an investigation of rapid thermal silicidation of nickel on silngle crystalline silicon wafers in the annealing range of $350-390^{\circ}C$. The samples annealed at temperatures from 350 to $390^{\circ}C$ have been analyzed by SEM(Scanning Electron Microscopy).

• Journal of Advanced Marine Engineering and Technology
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• 제29권5호
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• pp.560-570
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• 2005

In this paper, we discuss the tracking system for a wheelchair which can follow the path of a human target such as a nurse in hospital. The problem of human tracking is that it requires recognition of feature as well as the tracking of human positions. For this purpose the use of a high cost visual sensor such as laser finder or streo camera makes the tracking a high cost additional expense. This paper proposes the tracking system uses a low cost infrared range-finder and CCD camera, The Infrared range-finder and CCD camera can create a target candidate through each target recognition algorithm. and this information is fused in order to reduce the uncertainties of a target decision and correct the positional error of the human. The effectiveness of the proposed system is verified through experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1798-1799
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• 2011

In this paper, A new cost-effective and accurate input noise rejection method for High Speed Counter module of PLC (Programmable Logic Controller) is proposed. By using combination of simple additional logic circuit and the Timer Pulse function of general purpose MPU, Cost-effectiveness and improvement of accuracy of filtering function can be achieved. This proposed method is verified by simulation. This proposed method is much useful for simple industrial controller based on simple microprocessor because of simplicity, accuracy and low cost.

• Advances in aircraft and spacecraft science
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• 제10권5호
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• pp.393-418
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• 2023

Drones are increasingly used in logistics delivery due to their low cost, high-speed and straight-line flight. Considering the small cargo capacity, limited endurance and other factors, this paper optimized the pickup and delivery vehicle routing problem with time windows in the mode of "truck+drone". A mixed integer programming model with the objective of minimizing transportation cost was proposed and an improved adaptive large neighborhood search algorithm is designed to solve the problem. In this algorithm, the performance of the algorithm is improved by designing various efficient destroy operators and repair operators based on the characteristics of the model and introducing a simulated annealing strategy to avoid falling into local optimum solutions. The effectiveness of the model and the algorithm is verified through the numerical experiments, and the impact of the "truck+drone" on the route cost is analyzed, the result of this study provides a decision basis for the route planning of "truck+drone" mode delivery.

• 한국정보통신학회논문지
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• 제19권11호
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• pp.2751-2757
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• 2015

유도제어 시스템 체계 개발의 초기단계에는 운용 효과도 도출 및 요구사항 적합성 검토를 통한 체계 개략사양도출을 위해 효과도 분석을 수행한다. 본 논문에서는 M&S (Modeling & Simulation)를 활용하여 항법센서 성능과 환경영향(조류의 세기와 방향)에 따른 유도제어 시스템의 목표점 도달 정확도에 대한 운용 효과도 분석을 수행한다. 효과도 분석을 위해 6자유도 운동모델, 환경모델, 유도항법제어모델을 구성한다. 항법센서는 관성항법센서(Inertia Navigation Sensor, INS)와 도플러 속도센서(Doppler Velocity Log, DVL)로 구성하고, 환경변수는 조류(current)의 세기와 방향이다. 수치 시뮬레이션 결과는 CEP(Circular Error Probability)와 분산을 이용한 확률분석으로 분석한다. 효과도 분석 결과는 항법센서의 가격을 고려한 비용 대비 효율 분석에 활용하여 가격 대비 높은 성능의 센서 사양을 도출할 수 있다. 본 논문에서는 높은 수준의 INS와 낮은 수준의 DVL을 이용하면 가격 대비 성능이 높은 복합항법센서를 구성한다는 것을 보여준다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.137-140
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• 2000

In this paper, we have proposed an efficient test generation method for asynchronous circuits. The test generation is based on specification level, especially on Signal Transition Graph(STG)〔1〕 which is a kind of specification method for asynchronous circuits. To conduct a high-level test generation, we have defined a high-level fault model, called single State Transition Fault(STF) model on STG and proposed a test generation algorithm for STF model. The effectiveness of the proposed fault model and its test generation algorithm is shown by experimental results on a set of benchmarks given in the form of STG. Experimental results show that the generated test for the proposed fault model achieves high fault coverage over single input stuck-at fault model with low cost. We have also proposed extended STF model with additional gate-level information to achieve higher fault coverage in cost of longer execution time.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.132-137
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• 2015

A modular construction method includes factory-prefabricated room-sized volumetric units. Although low-rise buildings have been constructed worldwide using this method for more than 30 years, it is a relatively new technology in high-rise construction. There are three basic methods of constructing high-rise buildings using modular construction: the core method, the core-and-podium combination method, and the modular in-fill method. While the first two have been used in the USA and in several European countries, the third method, introduced in 2011 by an international cruise ship development firm, is a rather new approach for which there are few case histories. Therefore, its applicability and construction feasibility should be verified. As a pilot study to test the applicability of the modular in-fill method, a 12-story residential building was built in Korea. This paper describes a case study of the pilot project. The advantages and disadvantages of the method and its applicability in terms of cost effectiveness and construction schedule management were evaluated.