• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.5-5
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• 2000

Some of Spacecraft's structures are flexible so that a certain expected disturbance can easily excite a low frequency vibration on these structures, having very low natural damping. Such vibration will degrade the performance of the system, which should to be kept in a specific shape or attitude against the undesired vibration, In this paper, LQG/LTR controller is developed using an additional dynamic model to increase the performance of the frequency responses at low frequency area,

• 한국산업정보학회논문지
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• 제21권1호
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• pp.17-25
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• 2016

본 논문은 동기회로에서 누설 전류를 줄이기 위해서 사용되는 파워 스위치 구조를 결합한 새로운 구조의 저전력 비동기 회로 설계 방법을 제안하고자 한다. Static 방식, Semi-static 방식과 같은 기존의 지연 무관방식의 비동기 방식과 비교해서 다소 속도의 손해는 있지만, 파워 스위치에 의해서 데이터가 없는 상태에서는 누설 전력을 줄일 수 있고, 전체 사이즈가 작아짐으로써 데이터가 입력되는 순간의 스위칭 전력도 줄일 수 있는 장점이 있다. 따라서, 제안된 방법은 속도보다 저전력을 기본으로 하는 사물인터넷 시스템에서 요구되는 전전력 설계 방법이 될 것이다. 본 논문에서는 새로운 방식의 비동기 회로를 사용하여 $4{\times}4$곱셈기를 0.11um 공정으로 설계하고, 기존의 비동기 방식의 곱셈기와 스피드, 누설 전류, 스위칭 파워, 회로 크기 등을 비교하였다.

• Korean Chemical Engineering Research
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• 제55권6호
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• pp.745-753
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• 2017

본 연구에서는 도시 개발에 따라 왜곡된 도시 물 순환을 LID 시설을 통하여 자연적인 물 순환으로 되돌리고자 하는 설계전략이 제안된다. 이는 도시 개발 전과 후의 유황곡선이 동일하게 유지되는 최적의 LID 시설 설계용량을 결정함으로서 구현된다. 부산 녹산 국가산업단지의 일부지역이 연구대상지역으로 선정되었으며, 다양한 토지이용시나리오 및 LID 시설 설계용량에 대한 강우유출수 모의를 위하여 EPA SWMM이 구축되었다. 연구대상지역이 개발이전에 임야지역 또는 농경지역이라 가정하였을 경우, 도시 개발 이후에도 유황곡선이 도시 개발 전과 동일하게 유지되기 위해서는 불투수지역의 7.3% 또는 5.5%를 생태저류지의 면적으로 할당해야 함을 확인하였다. 또한 지역별 강우특성에 따른 생태저류지 설계용량의 민감도 분석을 수행한 결과, 농경지역의 개발 시에는 불투수지역의 3.8~5.5% 정도의 설계용량이 필요한 것으로 나타남에 따라 지역별 강우특성에 따라 생태저류지의 최적용량이 유의하게 달라질 수 있음을 살펴볼 수 있었다. 반면에, 생태저류지 각 층별 깊이의 변화에 따른 설계용량의 민감도 및 처리대상구역의 크기에 따른 민감도를 분석한 결과, 생태저류지의 설계 제원 및 처리대상구역의 크기에 따른 최적설계용량의 민감도는 크지 않은 것으로 나타났다.

• 대한임베디드공학회논문지
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• 제13권3호
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• pp.143-149
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• 2018

It has become ever harder to design reliable circuits with each nanometer technology node; under normal operation conditions, a transistor device can be affected by various aging effects resulting in performance degradation and eventually design failure. The reliability (aging) effect has traditionally been the area of process engineers. However, in the future, even the smallest of variations can slow down a transistor's switching speed, and an aging device may not perform adequately at a very low voltage. Therefore, circuit designers need to consider these reliability effects in the early stages of design to make sure there are enough margins for circuits to function correctly over their entire lifetime. However, such an approach excessively increases the size and power dissipation of a system. As the impact of reliability, new techniques in designing aging-resilient circuits are necessary to reduce the impact of the aging stresses on performance, power, and yield or to predict the failure of a system. Therefore, in this paper, a novel low power on-chip self-tuning circuit considering the aging effects has been proposed.

• 한국생산제조학회지
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• 제20권6호
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• pp.761-766
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• 2011

In this study, the optimized design profiles between a seal ring and a seal seat of contacting seal units has been proposed based on the FEM computed results. The maximum temperatures, the thermal distortions in axial and radial directions, and maximum contact normal stresses between a seal ring and a seal seat have been analyzed for various contact sealing profiles. The FEM computed results present that the contact area between seal rings and seal seats is very important for a good tribological performance such as low friction heating, low wear, high contact normal stress in a primary sealing components. The seal surface model III in which has a small sealing contact area shows low dilatation of primary sealing components, and high contact stress between a seal ring and a seal seat. This model with small contact surface of a seal ring produces high friction heating and contact stress. But the model III produces very small deformations of contacting sealing surface because of high convection heat transfer by cooling water circulation around the seal ring surface. Thus, the analysis results recommend a short width of a primary sealing unit rather than a big width of contact surfaces of contacting seal units for reducing a leakage and axial deformation of primary seal components.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권2호
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• pp.124-130
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• 2005

In this paper, low-power design and implementation techniques for DWT(Discrete Wavelet Transform) of the JPEG2000 compression are proposed. In DWT block of the JPEG2000, linear phase 9 tap and 7 tap filters are used. For low-power implementation of those filters, processor technique for DA(Distributed Arithmetic) filter and minimization technique for number of addition in CSD(Canonic Signed Digit) filter are utilized. Proposed filter structure consists of 3 blocks. In the first CSD coefficient block, every possible 4 bit CSD coefficients are calculated and stored. In second processor block, multiplication is done by MUX and addition processor in terms of the binary values of filter coefficient. Finally, in third block, multiplied values are output and stored in flip-flop train. For comparison of the implementation area and power dissipation, proposed and conventional structures are implemented by using Verilog-HDL coding. In simulation, it is shown that 53.1% of the implementation area can be reduced comparison with those of the conventional structure.

• ETRI Journal
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• 제33권4호
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• pp.611-620
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• 2011

Since card-type one-time password (OTP) generators became available, power and area consumption has been one of the main issues of hardware OTPs. Because relatively smaller batteries and smaller chip areas are available for this type of OTP compared to existing token-type OTPs, it is necessary to implement power-efficient and compact dedicated OTP hardware modules. In this paper, we design and implement a low-power small-area hardware OTP generator based on the Advanced Encryption Standard (AES). First, we implement a prototype AES hardware module using a 350 nm process to verify the effectiveness of our optimization techniques for the SubBytes transform and data storage. Next, we apply the optimized AES to a real-world OTP hardware module which is implemented using a 180 nm process. Our experimental results show the power consumption of our OTP module using the new AES implementation is only 49.4% and 15.0% of those of an HOTP and software-based OTP, respectively.

• ETRI Journal
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• 제30권1호
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• pp.33-46
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• 2008

This paper presents the experimental results of a low-power low-cost RF transceiver for the 915 MHz band IEEE 802.15.4b standard. Low power and low cost are achieved by optimizing the transceiver architecture and circuit design techniques. The proposed transceiver shares the analog baseband section for both receive and transmit modes to reduce the silicon area. The RF transceiver consumes 11.2 mA in receive mode and 22.5 mA in transmit mode under a supply voltage of 1.8 V, in which 5 mA of quadrature voltage controlled oscillator is included. The proposed transceiver is implemented in a 0.18 ${\mu}m$ CMOS process and occupies 10 $mm^2$ of silicon area.

• 한국농촌건축학회논문집
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• 제14권3호
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• pp.85-92
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• 2012

This study aims to evaluate the residential exterior environment and ascertain the factors having an effect on the visual environment viewed through the living room window. This study is based on a questionnaire on the exterior environment targeting residents living in the area of Nohyunng in Jeju city, Jeju-do. The results are as follows. First, residents are satisfied with the exterior environment as a whole; however, the longer-term residents' level of satisfaction is found to be relatively low while dissatisfaction is high. Additionally, there is a difference in satisfaction and dissatisfaction levels between the residents in their own housing and those in rental housing. The residents living in rental housing were found to have a relatively low level of satisfaction and high dissatisfaction. Second, in the case where the living room window faces roads, low satisfaction and high dissatisfaction levels with the visual environment were found, where the living room is on the first or second floor. Third, satisfaction and dissatisfaction with the exterior environment have a close correlation to the impression or nature elements of 26 questions but they show low correlation in size, height, color, design, traffic, artifact elements. Finally, as a result of extracting the factors influencing satisfaction and dissatisfaction with the visual environment, four factors were extracted including "Impression & Nature factor", "Building factor", "Design factor", and "Traffic volume & Artifacts factor". "Impression & Nature factors" is the most influencing factor with satisfaction and dissatisfaction and "Traffic volume & Artifacts factor" was found to have an effect on satisfaction, but not as clearly on dissatisfaction.

• 한국조경학회지
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• 제29권1호
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• pp.32-40
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• 2001

The purpose of designing Haebaragi park, legally designated as children park, is to make a place for children including residents performing outdoor recreation, various social interactions, and cultural activities. Design concept for space plan have twofold; the one is a positive and creative playing space and facilities for children, escaped from a monotonous playground, and the other is a cultural and social space for neighboring communities. The site having the area of 1,316.7 square meters, located in Nowon-Dong, Buk-Gu, Daegu metropolitan City, is just like a vest pocket park. The adjacent area had been developed a slum area with mixed ad visually conflicting land use patterns and low income groups. The children and residents living in the area do not have any public space suitable for playing and/or rest. After analyzing such locational characteristic as accessibility, land use of the communities, and potentials for park development, and such design concept as arrangement of facilities, efficient use of site, and functional allocation of park space, We have mad a plan for composition of spaces for various activities, provision of facilities based on estimation of user-demand and activities, and planting. In the design process, we have tried to harmonize functional spaces with facilities, and to organize all the functions as a whole. To improve urbanity and aesthetic shape of park design, we have introduced a central plaza, design of a pave floor, a torrent, large trees for shade, colonnades and so on. From this design project, we can develop the site as a children park for increasing creativities and various playing opportunities, and as a resident space for rest, cultural activities. In the future, it is required that many attempt to design and develop urban small space as a park for children and residents.