• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.830-833
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• 2004

An indoor package air-conditioner (PAC) has complex noise sources such as motor noise and fluid noise caused by the fan motor, heat transfer and shroud. Sound intensity techniques and ODS(Operational deflection shape) techniques are applied to identify the noise characteristics of an indoor air-conditioner's cabinet. The sound intensity is used to visualize the noise source locations. and the ODS to visualize the vibration pattern and to obtain the dynamic characteristics of the noise source. Acoustic intensity and operational deflection distribution are obtained in space domains as well as frequency domains. Using the visual information of source locations and its dynamic characteristics, the damping patch is applied to reduce structure borne noise in the cabinet. As a result, the noise emitted by the cabinet is reduced by 5dB.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.115-116
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• 2002

This study was carried out as one of efforts to overcome difficulties in air bearing design due to low stiffness and low damping. Hydrodynamic effects on hydrodynamic stiffness of a fluid film in a high speed air bearing with tow-row air sources are investigated. The hydrodynamic effects by the high speed over DN 1,000,000 and eccentricity of a proceeding which are not considered in conventional design of an air bearing need to be reconsidered. The hydrodynamic effects, which dominantly influence on the load capacity of air bearing, are caused mainly by proceeding speed, eccentricity, and the source positions. The two-row source arrangement in the air bearing produces quite unique hydrodynamic effects with respect to pressure distribution of the air film. Optimal arrangement of the two-row sources improves performance of an air bearing in film reaction force and loading capacity of high speed spindles. This study compares the pressure distribution by numerical simulation as a function of eccentricity of proceeding and the source positions. The air source position 1/7L form one end of an air bearing was found to be superior to source position of 1/4L. The dynamic stiffness were obtained using a two-dimensional cutting method which can directly measure the cutting reaction forces and the displacements of the spindle in two directions using a tool dynamometer and transducer sensors. Heat generation in the air film can not be negligible over the speed of DN 2,000,000. In order to analysis effects of heat generation on the characteristics of air bearing, high cooling bearing spindle and low cooling bearing spindle were tested and compared. Characteristics of the frequency response of shaft and motion of run out errors were different for the spindle. The test results show that, in the case of low cooling bearing spindle, the stiffness became smaller due to heat generation. The results, which were obtained for high speed region, may be used as a design information for spindle which can be applied to precision devices such as ultra precision grinding and ultra high speed milling.

• Journal of Information Display
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• 제2권4호
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• pp.23-28
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• 2001

Field emission characteristics of carbon nanotubes(CNTs) on four kinds of metallic substrates have been investigated under the irradiation of a laser. The field emission measurement reveals that after laser irradiation the current was increased and new humps at the field emission current was found. The current enhancement was thought to have occurred due to the fact that the electrical contact between CNTs and metals was improved due to the irradiation of the laser.

• 한국가구학회지
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• 제28권3호
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• pp.156-168
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• 2017

The digital information society that developed along with the 21st century is the 'Open-source Making Movement' which produces collective intelligence through open-source sharing and digital manufacturing tools, which is called 'Makers Movement'. The purpose of this paper is to analyze the case of Makers Movement in furniture design through 'IKEA Hacking' which arose simultaneously with the Makers Movement, and to study and present the prospect and direction of furniture design in the change of manufacturing industry. In this study, four design features were compared with IKEA hacking cases along with the establishment of 'community' which is a feature of Makers Movement. Four characteristics are first customized design, second derivative design through open source, third long -Tail effect design, and fourth, design using digital manufacturing tools. The prospect and direction of furniture design through this study are as follows: first, democratization of furniture design manufacturing, second job creation, third, coexistence of large and small enterprises, fourth promotion of various new technologies, and fifth, discovery of various furniture designers through 'Open System Organization'.

• 천문학논총
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• 제16권1호
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• pp.31-36
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• 2001

We present the characteristics of the 2K CCD camera at the Bohyunsan Optical Astronomy Observatory of the Korea Astronomy Observatory at the time of its development. The purpose of this paper is to support the observers who may need detailed information on the characteristics of the camera and to provide helpful information on the optimization' of a CCD camera for those who try to develop their own camera. The 2K CCD camera was optimized to have a gain of $1.8e^-/ADU$ and a read out noise of $7e^-$ from an experiment using radioactive $^{55}Fe$ X-ray source. The charge transfer efficiency was measured as 0.9999976 for serial and 0.9999942 for parallel direction, which means $0.5\%$ charge loss along the serial direction and $1.2\%$ along the parallel direction across the chip. The quantum efficiency of the camera was measured from an experiment using a homogeneous light source consisting of a halogen lamp and an integrating sphere with a monochromator. The resulting quantum efficiency of the camera peaked at the wavelength range 600-700 nm with the value of $\~0.89$.

• 대한전자공학회논문지SD
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• 제43권10호
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• pp.61-67
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• 2006

본 논문에서는 Poly-Si의 불규칙한 Grain boundary 분포로 인해 발생하는 문턱전압의 변화에 대해서도 일정한 전류를 흘려줄 수 있는 전류원을 제안하였다. 기존의 문턱전압 보상 전류원에 비해 넓은 입력전압 범위에서도 포화영역의 특성이 매우 향상되었으며 문턱전압의 변화에 따른 전류의 오차를 감소시킬 수 있었다. 마지막으로 HSPICE 시뮬레이션 과정을 통해 Poly-Si TFT의 특성곡선과 제안된 전류원의 특성곡선을 비교하였으며 각각의 입력전압에 대한 문턱전압의 변화에 따른 출력전류의 상대오차를 측정하였다.

• 대한가정학회지
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• 제43권11호
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• pp.17-30
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• 2005

The purpose of this study was to explore consumption status of scented textile products and to determine differences in consumption behaviors of scented textile products among subject groups separated by demographic (sex, age) and lifestyle (health concern, fashion involvement, innovativenss) characteristics. A total of 530 consumers who had used scented textile products participated in the web survey for the study. Consumer data were analyzed through descriptive statistics, chi-square test, factor analysis, t-test, ANOVA, and LSD test. In the results, the most often used products were small commodities, socks, bedding, and underwear of hub and flower scents. Consumers considered a product test as the most crucial information source and scent as the most significant decision making factor for purchase. Demographic and lifestyle group differences were found in some of the product types in use as well as in purchase behaviors (total spending amount, purchase venue, information source, considering factors when purchasing). The applicability of the study result to the theory of innovation adoption was discussed. Marketing implications were suggested based on the study results.

• 한국정보처리학회논문지
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• 제7권4호
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• pp.1217-1226
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• 2000

Traditionally, Mobile Teletraffic model consists of two sub-models, i.e. the network traffic model and the traffic source model. In this paper, we present the traffic source model by developing MobCall (Mobile Call Simulator) which analyses various mobile wireless environments based on regional characteristics that the base stations are located. User mobility is presented by regional average vehicle speeds and the transportation share rate. Moreover, the user mobility on subway, which is increasing in urban area, is considered in MobCall. And also, user's movements on highway are considered in MobCall. The object-oriented simulation platform, C++SIM, is used to implement MobCall. Using MobCall, the accumulated number of calls in residential and commercial regions, the handoff rate with respect to traffic sources of Seoul, the handoff rate on highway, and the handoff rate according to the call duration are presented. MobCall enables the simulation of dynamic handoff buffering and functional entity control of one base station according to the changes in user's calling pattern at the design phase. Also, when a new town is under construction by a detailed plan, MobCall is used to design the mobile network with regional characteristics and user mobility considered.

• 디지털융복합연구
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• 제12권5호
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• pp.451-458
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• 2014

본 논문에서는 관광의 1차적인 정보원으로서의 홈페이지와 관광홍보물의 언어학적 전환의 특징을 살펴보고자 한다. 즉 관광관련 사이트의 한국어 원문과 영어 번역물을 비교하면서 관광정보 텍스트가 올바르게 언어전환 되었는지 점검하고 나아가 전환된 영어번역물과 한국어 원문을 대조하면서 번역물에서 발생하는 언어규약과 의사소통의 특징을 살펴본다. 특히 한국어와 영어는 언어유형에서 대조적인 언어로서 번역을 통해 전환되었을 때 특이한 담화의 양상을 보인다. 즉 한국어에 비해 영어표현은 직설적이고 우회적인 표현을 피하는 경향이 있다. 또한 영어번역본에서는 영어 화자위주로 언어가 변형되어 표현됨을 주시할 수 있다. 이것은 영어를 사용하는 언어군에서 흔히 발생하는 양상으로 광의의 문화간의 차이로 간주될 수 있다. 따라서 외국관광객의 1차적 정보원으로서의 관광웹사이트는 관광정보를 제공하는 동시에 목적지의 문화를 간접적인 형태로 표현함으로써 사회적 이미지 형성과 문화간 차이를 대변하며 커뮤니케이션의 일환으로서 공손의 원칙과 Grice의 원칙을 준수하고 있다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.247-250
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• 1999

This paper presents characteristics of neuron-MOSFET for the implementation of logic circuits such at the inverter and D/A converter. Neuron-MOSFETS were fabricated using double poly CMOS process. From the measured results, it was found that noise margin of the inverter was dependant on the coupling ratio and a complete D/A characteristics of the source follower could be obtained by using any input Sate as a control gate.