• 한국산업융합학회 논문집
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• 제4권3호
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• pp.329-337
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• 2001

This simulator is developed for the analysis of a MOSFET based on Thermally Coupled Energy Transport Model(TCETM). The simulator has the ability to calculate not only stationary characteristics but also non - stationary characteristics of a MOSFET. It solves basic semiconductor devices equations including Possion equation, current continuity equations for electrons and holes, energy balance equation for electrons and heat flow equation, using finite difference method. The conventional semiconductor device simulation technique, based on the Drift-Diffusion Model (DDM), neglects the thermal and other energy-related properties of a miniaturized device. I, therefore, developed a simulator based on the Thermally Coupled Energy Transport Model (TCETM) which treats not only steady-state but also transient phenomena of such a small-size MOSFET. In particular, the present paper investigates the breakdown characteristics in transient conditions. As a result, we found that the breakdown voltage has been largely underestimated by the DDM in transient conditions.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.389.2-389.2
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• 2016

The flexible solid state device has been widely studied as portable and wearable device applications such as display, sensor and curved circuits. A zero-bias operation without any external power consumption is a highly-demanding feature of semiconductor devices, including optical communication, environment monitoring and digital imaging applications. Moreover, the flexibility of device would give the degree of freedom of transparent electronics. Functional and transparent abrupt p/n junction device has been realized by combining of p-type NiO and n-type ZnO metal oxide semiconductors. The use of a plastic polyethylene terephthalate (PET) film substrate spontaneously allows the flexible feature of the devices. The functional design of p-NiO/n-ZnO metal oxide device provides a high rectifying ratio of 189 to ensure the quality junction quality. This all transparent metal oxide device can be operated without external power supply. The flexible p-NiO/n-ZnO device exhibit substantial photodetection performances of quick response time of $68{\mu}s$. We may suggest an efficient design scheme of flexible and functional metal oxide-based transparent electronics.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권8호
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• pp.3090-3102
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• 2015

The accuracy of an augmented reality (AR) application is highly dependent on the resolution of the object's image and the device's computational processing capability. Naturally, a mobile smart device equipped with a high-resolution camera becomes the best platform for portable AR services. AR applications require significant energy consumption and very fast response time, which are big burdens to the smart device. However, there are very few ways to overcome these burdens. Computation offloading via mobile cloud computing has the potential to provide energy savings and enhance the performance of applications executed on smart devices. Therefore, in this paper, adaptive mobile computation offloading of mobile AR applications is considered in order to determine optimal offloading points that satisfy the required quality of experience (QoE) while consuming minimum energy of the smart device. AR feature extraction based on SURF algorithm is partitioned into sub-stages in order to determine the optimal AR cloud computational offloading point based on conditions of the smart device, wireless and wired networks, and AR service cloud servers. Tradeoffs in energy savings and processing time are explored also taking network congestion and server load conditions into account.

• 한국태양에너지학회 논문집
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• 제38권6호
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• pp.1-14
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• 2018

The shading device on the window of the building can be an passive solution to reduce the cooling load and lighting energy, as well as improving the indoor comfort. It is also an architectural element that must be considered for building energy-efficient buildings such as eco-buildings and zero-energy buildings. However, due to various building environments and various shading devices, the installation of excessive shade may lead to the risk of losing the effectiveness of windows. In this study, we propose a method for optimal automatic control of shading device and evaluate its effectiveness by energy analysis of several shading devices.

• 한국전기전자재료학회논문지
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• 제27권11호
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• pp.740-745
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• 2014

ZnO nanowires were grown by hydrothermal synthesis process and piezoelectric poly vinylidene fluoride (PVDF) was then coated on top of the ZnO-nanowires by spray-coating technique. The composite layer of ZnO-nanowires/PVDF was applied to an energy harvesting device based on piezoelectric-conversion mechanism. A defined mechanical force was given to the nanogenerator device to evaluate their electric power generation characteristics, where output current density and voltage were examined. Electric power generation property of the ZnO-nanowires/PVDF based nanogenerator device was compared to that of the nanogenerator device with ZnO-nanowires as single active layer. Effect of the ZnO-nanowires on improvement of power generation was discussed to examine its feasibility for the nanogenerator device.

• 인터넷정보학회논문지
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• 제24권2호
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• pp.57-66
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• 2023

현재, 에너지 효율 향상으로 소비감축을 시행하는 새로운 에너지 시스템이 대두되고 있다. 이에 스마트그리드가 확산되면서 계시별 요금제가 확대되고 있다. 계시별 요금제는 계절별 / 시간별로 요금을 다르게 적용해 사용량에 따라 요금을 내는 요금제이다. 본 연구에서는 에너지 전력 사용량 데이터를 예측하기 위해, 온도/요일/시간/계절 등 외부 요인을 고려하고 시계열 예측 모델인 LSTM을 활용한다. 이러한 에너지 사용량 예측 모델을 기반으로 기기별 사용패턴을 분석하여 전력 에너지를 최대부하시간대에서 경부하시간대로 수요이전 함으로써 에너지 사용요금을 절감한다. 기기별 사용패턴을 분석하기 위해서는 시간대별로 기기의 사용량 패턴을 학습 및 분류하는 clustering 기법을 사용한다. 정리하자면, 본 연구에서는 사용자의 전력 데이터 사용량을 기반으로 사용량과 사용 요금을 예측 및 기기별 사용패턴을 분석하고 분석 기반의 맞춤형 수요이전 서비스를 제공함으로써 사용자에게 요금 절감 효과를 가져다 준다.

• Journal of Radiation Protection and Research
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• 제43권3호
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• pp.97-106
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• 2018

Background: A cargo container scanner using a high-energy X-ray generates a fan beam X-ray to acquire a transmitted image. Because the generated X-rays by LINAC may affect the image quality and radiation protection of the system, it is necessary to acquire accurate information about the generated X-ray beam distribution. In this paper, a diode-based multi-channel spatial dose measuring device for measuring the X-ray dose distribution developed for measuring the high energy X-ray beam distribution of the container scanner is described. Materials and Methods: The developed high-energy X-ray spatial dose distribution measuring device can measure the spatial distribution of X-rays using 128 diode-based X-ray sensors. And precise measurement of the beam distribution is possible through automatic positioning in the vertical and horizontal directions. The response characteristics of the measurement system were evaluated by comparing the signal gain difference of each pixel, response linearity according to X-ray incident dose change, evaluation of resolution, and measurement of two-dimensional spatial beam distribution. Results and Discussion: As a result, it was found that the difference between the maximum value and the minimum value of the response signal according to the incident position showed a difference of about 10%, and the response signal was linearly increased. And it has been confirmed that high-resolution and two-dimensional measurements are possible. Conclusion: The developed X-ray spatial dose measuring device was evaluated as suitable for dose measurement of high energy X-ray through confirmation of linearity of response signal, spatial uniformity, high resolution measuring ability and ability to measure spatial dose. We will perform precise measurement of the X-ray beamline in the container scanning system using the X-ray spatial dose distribution measuring device developed through this research.

• 한국항해학회지
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• 제14권4호
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• pp.41-52
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• 1990

부유식 진동수주형 파력발전기는 불규칙한 해상 상태에서의 작동으로 인하여 흡수효율의 저하를 필수적으로 수반한다. 본 논문에서는 입사파의 에너지를 적절히 흡수할 수 있는 파력발전기를 초기설계하여 모델로 이용하였으며, 이 모델의 유체력추정에는 3차원 특이점 분포법을 사용하였다. 그리고, 가변구조 시스템으로 알려진 슬라이딩 모드기법을 이용하여 파의 상태 변화에 따른 파력발전기의 자세와 위치를 제어함으로써 흡수파력의 효율을 중대시킬 수 있는 시스템을 제안하고 있다.

• 한국군사과학기술학회지
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• 제18권2호
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• pp.139-145
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• 2015

In this paper, the flexible piezoelectric nanocomposite generator(NCG) device based on $BaTiO_3$ nanostructures was fabricated via simple and low-cost spin coating method. The $BaTiO_3$ nanostructures synthesized by self-assembly reaction showed dendrite morphologies. To produce the piezoelectric nanocomposite(p-NC layer) which acts as an electric energy source in NCG device, the piezoelectric nanopowders($BaTiO_3$) were dispersed in polydimethylsiloxane(PDMS). Sequently, the p-NC layer was inserted in two dielectric layer of PDMS; these layers enabled the NCG device flexibility as well as durability prohibiting detachment(exfoliation) for significantly mechanical bending motions. The fabricated NCG device shows average maximum open circuit voltage of 6.2 V and average maximum current signals of 300 nA at 20 wt% composition of $BaTiO_3$ nanostructures in p-NC layer. Finally, the flexible energy harvester generates stable output signals at any rate of frequency which were used to operate LCD device without any external energy supply.

• International Journal of Internet, Broadcasting and Communication
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• 제10권2호
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• pp.7-12
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• 2018

The spread of IoT (Internet of Things) technology that connects objects based on wired / wireless networks is accelerating, and IoT-based smart home technology that constitutes a super connected network connecting sensors and home appliances existing inside and outside the home is getting popular. In addition, demand for alternative energy technologies such as photovoltaic power generation is rapidly increasing due to rapid increase of consumption of energy resources. Recently, small solar power systems for general households as well as large solar power systems for installation in large buildings are being introduced, but they are effectively implemented due to limitations of small solar panels and lack of power management technology. In this paper, we have studied smart home structure and IoT / IoL device discovery algorithm for energy harvesting system based on photovoltaic power generation, It is possible to construct an efficient smart home system for device control.