• 한국디지털건축인테리어학회논문집
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• 제9권2호
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• pp.57-65
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• 2009

Housing Re-Development business is to improve the environment of old residential area and secure insufficient infrastructure facilities for the public, and to provide housing of fine quality for the individuals and it is taken as an opportunity for the individuals to be able to increase their property. However, it is true that the benefits from the redevelopment has not offered to the original dwellers who has lived there for a long time. This research studies the related systems of the Rental House Redevelopment Supply Service and is to present the schema to raise resettlement rate through the investment on the rate of tenants who chose the rental house and their specific characters. This study is to present the reform measures about the following 3 problems, on the basis of prior theoretical studies which deals with the common factors having low rate to move in the rental house of the tenants. (1) Physical side, the problem of supply structure, which is not appropriate Housing Supply Structure, (2) Psychological side, the problem of socially excluded rental house residents (3) Economical side, low re-settlement rate of tenants caused from the unreasonableness of the estimated rental value. This study presents that the compulsory rental housing supply rate should be changed to the gross area not from the number of households, and the supply of rental houses should correspond to the household size of tenants through prior demand survey. Secondly, it proposes the housing complex layout for intermixing to solve the social problems to allow a housing for sale and rental houses mixing in a building. And it proposes that the rental value should be calculated considering the neighboring value and in the long run, it should be calculated considering the tenants' income instead construction cost estimate. Also, it should be arranged to provide an opportunity to create income through resident welfare center improvement and provide self-sufficiency functions leading residents to participate in the residential area's repairing and maintenances.

• 대한전자공학회논문지SD
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• 제47권3호
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• pp.18-27
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• 2010

본 논문에서는 offset self-calibration 기법을 적용한 7-bit 1GSPS folding-interpolation A/D 변환기를 제안한다. 제안하는 A/D 변환기는 folding rate 2, interpolation rate 8의 1+6 구조로 고속 동작에 적합하게 설계되었다. 또한 offset self-calibration 회로를 설계하여 공정 mismatch, 기생 저항, 기생 캐패시턴스 등에 의한 offset-voltage의 변화를 감소시켜 A/D 변환기의 성능 특성을 향상 시켰다. 제안하는 A/D 변환기는 1.2V 65nm 1-poly 6-metal CMOS 공정을 사용하여 설계 되었으며 유효 칩 면적은 $0.87mm^2$, 1.2V 전원전압에서 약 110mW의 전력소모를 나타내었다. 측정 결과 샘플링 주파수 800MHz, 입력 주파수 250MHz에서 39.1dB의 SNDR 특성을 보여주었으며, offset self-calibration 회로를 사용 하지 않은 A/D 변환기에 비해 SNDR이 약 3 dB 향상되었다.

• 융합정보논문지
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• 제12권2호
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• pp.17-22
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• 2022

현재 주택보급률은 100%를 넘기고 지속적으로 보급률이 증가하고 있다. 이러한 주택보급률은 주거 서비스 정책에 있어 양적 공급 중심에서 주거 환경의 질 향상으로 변화되고 있다. 주택보급률 증가에도 여전히 주거 취약계층에 대해서는 실질적 접근이 어렵고 필요한 시기에 주거서비스를 이용하기에는 미흡한 부분이 많이 있다. 또한, 주거취약계층의 범위 확대로 주거 서비스에 대한 수요가 증가하고 있다. 이러한 문제를 보완하기 위해 정책 및 지원 사업 확대를 통해 주거취약계층에 대한 물량 확보 및 공급계획을 수립하고 있지만 독립적인 생활을 보장 할 수 없는 시설 및 공동입주가 주를 이루고 있다. 본 논문에서는 취약계층 주거 서비스를 지원하기 위한 IoT 환경 기반 취약계층 주거 지원 시스템을 제안한다. 제안 시스템은 주거 환경의 질을 향상하고 서비스 중심의 지원 서비스를 제공한다. 제안시스템을 통해 취약계층의 삶의 질을 향상하고 자립 생활이 가능한 주거 환경을 지원하여 적절한 사회참여 기회를 제공 받을 수 있다. 향후 연구로는 다양한 취약계층을 고려한 시스템으로 확장하여 사회적 약자 증가로 발생하는 문제를 보완한다.

• Journal of Nutrition and Health
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• 제22권2호
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• pp.108-117
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• 1989

The purpose of this study was aimed to investigate the historical tends of population growth which has reflected direct effect of the ratio of food self sufficiency in Korea between the year of 1910 and 1980. Author divided the whole years between 1910 and 1980 into five different periods ; colonial period from 1910 to 1945, post colonial period from 1945 to 1950, Korean war period from 1950 to 1955, post Korean war period from 1955 to 1960, fast economic growing period 1960~1980. The ratio of national food self sufficiency has been profoundlly affected by dual factors ; rate of population group and increment of GNP which reflect the national economic development. Total food production never reached the level of population growth ratio in Korea. As a result food demand and supply has shown imbalaced condition which leads to import foods from outside contury to compensate food shortage. The increment of GNP sharply cut down the cereal consumption. The consumption of fish, milk, eggs and meat reflected to increase since 1970.

• Tribology and Lubricants
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• 제18권5호
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• pp.357-363
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• 2002

The vibration characteristics of the pad fluttering in a fluid film tilting pad journal bearing (4-pad LBP) have been investigated experimentally under the different values of oil supply flow rate, bearing load and shaft speed. The vibration characteristics of the pad fluttering are estimated by measuring the time signal of circumferential distribution of the film thickness and the cascade plot of the response of the relative displacement between the bearing and the shaft. It is shown that the vibration frequency of the pad fluttering has a sub-synchronous frequency and almost does not change by the increase of shaft speed. However the vibration amplitude is increased by the increase of shaft speed. From those experimental results, pad fluttering can be thought of as a self-excited vibration. The incipient pad fluttering velocity is increased by the increase of oil supply flow rate and by the decrease of bearing load. It is observed that the vibration amplitude of the pad fluttering can be decrease by the control of supply oil flow rate effectively. And also It is known that the outbreak of pad fluttering does not concern with the shaft vibration.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
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• pp.228-234
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• 2000

The vibration characteristics of the pad fluttering in a fluid film tilting pad journal bearing(4-pad LBP) have been investigated experimentally under the different values of oil supply flow rate, bearing load and shaft speed. The vibration characteristics of the pad fluttering are estimated by measuring the time signal of circumferential distribution of the film thickness and the cascade plot of the response of the relative displacement between the bearing and the shaft. It is shown that the vibration frequency of the pad fluttering has a sub-synchronous frequency and 31mos1 does not change by the increase of shaft speed. However the vibration amplitude is increased by the increase of shaft speed. From those experimental results, pad fluttering can be thought of as a self-excited vibration. The incipient pad fluttering velocity is increased by the increase of oil supply rate and by the decrease of bearing load. It is observed that the vibration amplitude of the pad fluttering can be decreased by the control of supply oil flow rate effectively. And also It is known that the outbreak of pad fluttering does not concern with the shaft vibration.

• 한국정밀공학회지
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• 제23권5호
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• pp.177-183
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• 2006

A tape feeder is an important feeding device to supply micro-chips such as 1005 and 0603 components to PCB in SMT process. Traditionally, tape feeding methods using sprocket wheel mechanism has been used for the pickup system of chip-mounters. However, there is growing needs for new feeding mechanism with high accuracy and confidence as electric components are getting much smaller. Thus, recently, a tape feeder using cam-slider mechanism is developed to meet such requirements. The major advantages of developed system are; significantly reduced indexing and backlash errors, slim and compact design, and improved repetitive capacity compared to existing system. In this paper, the performance evaluation criteria for the developed tape feeder are suggested. Stability against induced vibration, positioning accuracy, cycle time, durability and supply error rate are estimated using developed self testers. As a result, the excellence of developed tape feeding mechanism is validated using the effective rating methods.

• ETRI Journal
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• 제31권6호
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• pp.755-764
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• 2009

This paper presents a switched self-biasing and a tail current-shaping technique to suppress the 1/f noise from a tail current source in differential cross-coupled inductance-capacitance (LC) voltage-controlled oscillators (VCOs). The proposed LC VCO has an amplitude control characteristic due to the creation of negative feedback for the oscillation waveform amplitude. It is fabricated using a 0.13 ${\mu}m$ CMOS process. The measured phase noise is -117 dBc/Hz at a 1 MHz offset from a 4.85 GHz carrier frequency, while it draws 6.5 mA from a 0.6 V supply voltage. For frequency tuning, process variation, and temperature change, the amplitude change rate of the oscillation waveform in the proposed VCO is 2.1 to 3.2 times smaller than that of an existing VCO with a fixed bias. The measured amplitude change rate of the oscillation waveform for frequency tuning from 4.55 GHz to 5.04 GHz is 131 pV/Hz.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.1022-1027
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• 2002

This paper describes the fluttering characteristics of the upper pad in a tilting pad journal bearing(6-pad, LOP type) using a steam turbine. In order to investigate the phenomena of the upper pad fluttering experimentally, the absolute vibration of the upper pads the relative vibration between bearing and shaft and the circumferential distribution of the film thickness are measured under the different values of supply oil flow rate, shaft speed and bearing load. It can be known that the fluttering mechanism of the upper pads has a tendency of the self-excited vibration from the study of fluttering frequencies and amplitudes with the change of shaft speed. furthermore, it is observed that the incipient upper pad fluttering velocity is increased by the increase of oil supply flow rate and fluttering amplitude of the upper pads is increased by the decrease of the oil flow rate and by the increase of the bearing load.

• 한국소음진동공학회논문집
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• 제13권6호
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• pp.467-473
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• 2003

This paper describes the fluttering characteristics of the upper pad in a tilting pad journal bearing(6-pad, LOP type) using a steam turbine. In order to investigate the phenomena of the upper pad fluttering experimentally, the absolute vibration of the upper pads, the relative vibration between bearing and shaft and the circumferential distribution of the film thickness are measured under the different values of supply oil flow rate, shaft speed and bearing load. It can be known that the fluttering mechanism of the upper pads has a tendency of the self-excited vibration from the study of fluttering frequencies and amplitudes with the change of shaft speed. Furthermore, it is observed that the incipient upper pad fluttering velocity is increased by the increase of oil supply flow rate and the fluttering amplitude of the upper pads is increased by the decrease of the ell flow rate and by the increase of the bearing load.