• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.220-223
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• 2015

기존의 제품에서는 음악을 들으며 운동하는 과정에서 음악속도에 맞게 운동을 하는 방법을 사용하였다. 사용자가 운동중에 직접 음악 재생을 조절하는 방법은 좀 더 격한 음악을 재생하고자 했을 때 음악을 검색중 사용자의 운동의 흐름이 끊어지는 경우가 빈번하게 발생한다. 그러나 사용자의 걸음 속도를 이용해 음악 재생속도를 더 빠르게 한다면 효율적인 운동이 될 것이다. 본 논문에서는 신발의 깔창에 장착된 1개 이상의 압전센서를 활용하여 아두이노에서 걸음 수를 수집하고 수집된 압전센서 데이터를 이용하여 걸음 수를 이용한 걸음 속도의 측정 과정을 안드로이드 스마트폰에서 처리한다. 이렇게 측정된 걸음 속도를 통해 안드로이드 스마트폰에서 음악 재생 속도를 결정하여 사용자에게 쾌적한 운동 환경을 제공하는 것을 목적으로 한다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall
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• pp.251-258
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• 1999

The vibration control of bridge is studied considering the vibration characteristics of the Korean-type high-speed railway bridge. Fast nonlinear analysis is adopted as time integration method and the bridge and the train are modeled by FEM and sequentially moving constant forces respectively. Additional damping mechanism is indispensable to the Korean-type high-speed railway bridge because resonance vibration is excited under the maximum design speed. The optimal position and capacity of the damper is studied through the parametric studies, Transient vibration of the bridge is effectively controlled by such additional dampers which means that dampers play a role as structural damping. And also the maximum response of the bridge is reduced. Therefore it is verified that the increase of expected service life and the improvement of serviceability can be obtained through dampers.

• 한국정밀공학회지
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• 제30권7호
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• pp.667-672
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• 2013

This paper presents the development of a condition monitoring system that monitors the operating conditions of a reduction unit, such as the bearing temperature, gearbox vibration, and gear oil deterioration, and notifies the operator of potential problems or abnormal conditions. A series of field tests on high-speed rail and conventional lines was performed to identify the characteristics of temperature rise and vibration levels on the reduction unit during operation. The monitoring system was designed based on the proper sensor selection, measurement method, and signal analysis to optimize the interface with the operating system of high-speed trains. Application of this monitoring system to high-speed trains will play an important role in their proper maintenance and safe operation.

• KSTLE International Journal
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• 제7권2호
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• pp.35-44
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• 2006

Turbocharger bearings are under the circumstance of high temperature, moreover rotated at high speed. It is necessary to be designed overcoming the high temperature. So the type of oil inlet port, the inlet oil temperature and the sort of engine oil should be designed, controlled and selected carefully in order to reduce the bearing inside temperature. In this study, the influence of aerated oil on a high-speed journal bearing is also examined by using the classical thermohydrodynamic lubrication theory coupled with analytical models for viscosity and density of air-oil mixture in fluid-film bearing. Convection to the walls and mixing with supply oil and re-circulating oil are considered. The considered parameters for the study of bubbly lubrication are oil inlet port's type, oil aeration level and shaft speed. It is found that the type of oil inlet ports and shaft speed play important roles in determining the temperature and pressure, then the friction and load of journal bearing at high speed operation. Also, the results show that, under extremely high shaft speed, the high shear effects on aerated oil and the high temperature effects are canceled out each other. So, the bearing load and friction show almost no difference between the aerated oil and pure oil.

• Tribology and Lubricants
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• 제23권5호
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• pp.207-218
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• 2007

Turbocharger bearings are under the circumstance of high temperature, moreover rotated at high speed. It is necessary to be designed overcoming the high temperature. So the type of oil inlet port, the inlet oil temperature and the sort of engine oil should be designed, controlled and selected carefully in order to reduce the bearing inside temperature. In this study, the influence of aerated oil on a high-speed journal bearing is also examined by using the classical thermohydrodynamic lubrication theory coupled with analytical models for viscosity and density of air-oil mixture in fluid-film bearing. Convection to the walls and mixing with supply oil and re-circulating oil are considered. The considered parameters for the study of bubbly lubrication are oil inlet port's type, oil aeration level and shaft speed. It is found that the type of oil inlet ports and shaft speed play important roles in determining the temperature and pressure distribution, then the friction in a journal bearing at high speed operation. Also, the results show that, under extremely high shaft speed, the high shear effects on aerated oil and the high temperature effects are canceled out each other. So, the bearing load and friction show almost no difference between the aerated oil and pure oil.

• 한국멀티미디어학회논문지
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• 제8권12호
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• pp.1649-1657
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• 2005

In this paper, a fast implementation of JPEG is discussed and its application to multimedia service is presented for mobile wireless internet. A fast JPEG player is developed based on several fast algorithms for mobile handset. In the color transformation, RCT is adopted instead of ICT for JPEG source. For the most time-consuming DCT part, the binDCT can reduce the decoding time. In upsampling and RGB conversion, the transformation from YCbCr to RGB 16 bit is made at one time. In some parts, assembly language is applied for high-speed. Also, an implementation of multimedia in mobile handset is described using MJPEG (Motion JPEG) and QCELP(Qualcomm Code Excited Linear Prediction Coding). MJPEG and QCELP are used for video and sound, which are synchronized in handset. For the play of MJPEG, the decoder is implemented as a S/W upon the MSM 5500 baseband chip using the fast JPEG decoder. For the play of QCELP, the embedded QCELP player in handset is used. The implemented multimedia player has a fast speed preserving the image quality.

• 한국컴퓨터정보학회논문지
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• 제11권1호
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• pp.243-250
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• 2006

모바일 단말기 장치가 발전하면서 컴퓨터로만 할 수 있었던 게임, 인터넷, 금융 서비스 등을 이동 단말기를 이용하여 처리할 수 있다. 본 논문에서는 펜티엄급 PC에서 유행하던 게임을 이동 단말기에서 재생가능성 하도록 재구성하고, 자동화 가능한 재구성 요소를 정리하여 아바타 변환기로 개발하고자 한다. 즉, 기존의 자원을 최대한 재활용하여 이동 단말기용 컨텐츠 개발 속도를 향상시킬 수 있는 방법을 제안하고자 한다. 플랫폼의 제약사항을 고려하여 기존의 컴퓨터의 아키텍처를 모바일 플랫폼에서 동작 가능한 로직과 리소스로 구분하여 변환하는 동작이 아바타 변환기의 주 기능이다. 이동 통신 사업자의 플랫폼 종류에 따른 다수의 컨텐츠 개발에 공용의 로직과 리소스를 변환함으로써 개발 속도를 향상시킬 수 있다.

• 한국통신학회논문지
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• 제31권12B호
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• pp.1017-1027
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• 2006

최근 통신사업자들은 통신설비의 효율화 및 새로운 수익창출을 위해 하나의 공통된 IP 네트워크에서 기존의 초고속인터넷서비스에 음성서비스와 비디오서비스를 동시에 서비스하는 Triple Play Service를 제공하기 시작했다. 본 연구에서는 최근 이러한 통신서비스의 변화를 고려해 IP 네트워크에서 TPS 제공을 위한 가입자망의 대역설계 방법에 대해 몇 가지 대안을 제시하고, 제시하는 각 방법의 특성을 수치실험을 통해 비교 분석하여 가입자망의 실용적인 설계방안을 제시한다. 이를 위해 우선 연결레벨에서 초고속인터넷서비스와 프리미엄서비스를 위한 대역설계 방법을 제시하고, 두 서비스가 대역을 공유하는 TPS 환경에서 각 서비스의 서비스 품질을 보장하기 위해 가입자 수용장치의 대역을 논리적으로 분리하여 대역을 설계하는 방법을 제안한다. 그리고 제안된 방법을 바탕으로 ns-2를 이용해 가입자의 규모에 따른 설계대역량을 제시한다. 또한 프리미엄서비스의 서비스 품질을 보장하기 위해 앞서 산출한 연결레벨의 설계대역량을 이용해 패킷레벨에서 DiffServ 기반의 엄격한 우선순위스케줄링 방식을 통한 차별화된 서비스 제공방안을 가정해 기존의 FIFO 방식과 성능실험을 통해 비교 분석한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.109-112
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• 2000

The satellite communications are expected to play an important role to provide broadband multimedia services in the 21st century. According to this requirements, this paper describes the design and implementation of ATM-based high speed satellite modem ASIC chipset. The ASIC chip consists of three main parts, CODEC, Modulator and Demodulator. It supports burst and continuous mode operation with TDMA frame consisted of Reference bursts, Inbound burst, and Traffic burst. The maximum transmission rate is OC-3 (155Mbps) and the maximum operating clock speed is 220MHz. This ASIC chip was implemented with 0.25um CMOS technology.

• 소음진동
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• 제11권3호
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• pp.471-476
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• 2001

This paper focuses on the numerical prediction of airflow-induced sound in DVD drives. As a first step, computational fluid dynamics (CFD) is conducted to evaluate flow field characteristics due to the high-speed disk rotation, and to support the acoustic analysis. Acoustic analogy based on Ffowcs Wi1liams-Hawkings (FW-H) equation is adopted to predict aeroacoustic noise patterns. The integral solution for quadrupole volume source is included to identify the turbulence noise generated inside the DVD tray. The strength of sound pressure revel with respect to rotating speed is discussed to meet upfront demand on the high fidelity product development. The present study also focuses on the noise directivity and examines how much the sound noise is sensitive to change in rotating speed. Near-field noise is strongly affected by the flow field characteristic, which is caused by the complex shape of the tray. For a mid-field, the quadrupole noise play as a counterpart of thickness noise or loading noise, so it generates different sound noise Patterns compared with those in the near field.