• 한국정보통신학회논문지
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• 제13권5호
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• pp.1030-1037
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• 2009

현재 SAW 센서는 많은 발전을 해왔고 온도나 압력용 SAW 센서를 저전력, 고속 신호 처리로 하기 위해서는 TDS(Time Domain Sampling) 방식을 이용한 리더기 플랫폼이 필요하다. 이러한 리더기를 제작하기 위해서는 SAW 센서의 표준 응답신호와의 변화된 응답시간과의 짧은 시간차를 측정하기 위해 고속의 타이머가 필요하게 된다. 여기서 제안하는 플랫폼은 SAW 센서에 신호를 받아서 비교기로 아날로그 신호를 디지털 신호로 전환하여 그 전환된 신호를 타이머 모듈에서 읽어 들여 신호들의 시간차를 측정하여 표시하여 나노초(Nano Second) 단위의 시간을 측정하는 방법을 제안 하고자 한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1798-1799
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• 2011

In this paper, A new cost-effective and accurate input noise rejection method for High Speed Counter module of PLC (Programmable Logic Controller) is proposed. By using combination of simple additional logic circuit and the Timer Pulse function of general purpose MPU, Cost-effectiveness and improvement of accuracy of filtering function can be achieved. This proposed method is verified by simulation. This proposed method is much useful for simple industrial controller based on simple microprocessor because of simplicity, accuracy and low cost.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.879-883
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• 2000

A system for measuring and adjusting the oscillating frequency of a balance wheel whick determins the accuracy of mechanical timers. The balance wheel oscillates rotatively suspended by a hair spring which is welded at the other end to the pivot tube. The natural oscillatory frequency of the balance wheel is determined by the length of hairspring from the balance wheel to the point if other parameters the length in the torsional oscillation model are not changed, so the frequency of the balance wheel can be adjusted to meet a requirement by the adjustment of the hairspring length using ultrasonic welding. And the movement of wheel teeth is measured in realtime by a high speed photo fiber sensor and Auto Correlation is used to find a more accurate oscillation period from the measured signal with some variations.

• 한국유체기계학회 논문집
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• 제11권3호
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• pp.50-55
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• 2008

The diverter system is a key component in achieving a high accuracy liquid flow rate standard using a static gravimetric system with a flying start and stop method. The diverter is a moving device used to direct flow alternately along its normal course(by pass) or towards the weighing tank. The time needed for collection into the weighing tank is measured using a timer. So it is important to the diversion period is sufficiently fast and triggering point of timer which is determined the filling time. On this studies show that uncertainty of diverter system for changing diversion speed and triggering point was estimated in accordance with Guide to The Expression of Uncertainty in Measurement(ISO).

• 한국멀티미디어학회논문지
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• 제8권2호
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• pp.258-268
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• 2005

이동 컴퓨팅 환경에서 이동 중인 호스트에게 멀티캐스트 서비스를 효율적으로 제공하는 것은 쉬운 일이 아니다. 양방향 터널링 기법은 캡슐화와 삼각 라우팅의 오버헤드를 야기하는 반면, 원격 가입 기법은 빈번한 트리 재구성을 필요로 하는데 이는 고속으로 이동하는 호스트에게는 비효율적이다. 본 논문에서는 호스트의 이동 정보에 근거하여 원격 가입 기법과 양방향 터널링 기법 사이의 장점을 찾고자 하는 이동 정보에 근거한 모바일 멀티캐스팅(MBMOM) 기법을 제안한다. 만약 호스트의 이동 속도가 고속이라고 판단되면 양방향 터널링 기법을 사용하여 홈 에이전트가 멀티 캐스트 패킷을 전달하게 된다. 만약 호스트의 이동 속도가 저속이라고 판단되면 원격 가입 기법이 적용되며 외래에이전트는 멀티 캐스트 그룹에 가입을 시도한다. 본 논문에서 제안하는 기법의 성능을 분석하기 위하여 분석 모델을 개발하였으며, MOM(Mobile Multicast)과 RBMOM (Range Based MOM), TBMOM(Timer Based MOM) 기법과 비교하여 시뮬레이션을 실시하였다. 시뮬레이션의 결과는 본 논문의 기법이 호스트의 이동 속도와 멀티캐스트 그룹의 크기 측면에서 위의 세 기법들보다 전달시간이 적게 걸리는 것을 보여주고 있다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1042-1046
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• 2008

Both the weighing bridge and the diverter system is a important component in achieving a high accuracy liquid flow rate standard using a static gravimetric method. The weighing bridge is a tank which weighing collected flow with a load cells. The diverter is a moving device used to direct flow alternately along its normal course(by pass) or towards the weighing tank. The time needed for collection into the weighing tank is measured using a timer. So it is important to the diversion period is sufficiently fast and triggering point of timer which is determined the filling time. On this studies show that the measurement deviation of load cell and uncertainty of diverter system for changing diversion speed and triggering point was estimated in accordance with Guide to The Expression of Uncertainty in Measurement(ISO).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.915-916
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• 2007

There are many equipments for the Short Circuit Test, for example Short Circuit Generator, Induction Motor, Sequence Timer, Exciter, CLR, Back Up Breaker, Making Switch and TRV etc. Especially Back up Breaker and Making Switch are very important equipments to test the short circuit test. A role of a Back up Breaker is to break high-voltage and high-current for short circuit test and a Making Switch should be operated always same speed/time and kept electrical-mechanical characteristics to make the voltage and current of short circuit test. This study introduces to the short circuit test also to kinds, principal movements and compare them of Back up Breaker and Making Switch.

• Journal of Biosystems Engineering
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• 제12권3호
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• pp.7-16
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• 1987

This study was carried out to develop a microcomputer-based data acquisition and control system which was able to collect the data of engine performance test automatically and control the speed and load of the engine. The results of the study are summarized as follows: 1. The signal processing devices, which were able to measure cylinder pressure, coolant temperature, compositions of exhaust gas, fuel consumption, engine rpm and torque etc., were developed. The results of calibration showed that all of devices had high accuracy ranging from 0.3% to 0.69% respectively. 2. The PIA (peripheral interface adapter) for interfacing digital signal and PTM (programmable timer module) for displaying real time every 0.0408 sec were designed and developed. 3. An engine-speed control system using a stepping motor and driver was developed. The control system had the stability, and faster settling time than the manual control system. 4. The automatic control system of electrical dynamometer, which was able to control the speed and load of dynamometer, was developed with a SSD (shackleton system driver) and D/A converter. 5. The computer programs, which were able to collect and process the data of engine tests, were developed using both the machine language and BASIC.

• 한국정보과학회논문지:정보통신
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• 제31권2호
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• pp.188-195
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• 2004

본 논문에서는 적응변조코딩(Adaptive Modulation and Coding) 기법을 사용하는 CDMA 무선 통신 시스템에서의 TCP 성능을 분석한다. AMC를 사용하는 무선 채널은 패킷 손실 확률이 매우 낮고 대역폭이 시간에 따라 크게 변하는 특성을 갖는다. 무선채널 대역폭의 큰 변화 때문에 전송계층 프로토콜로 TCP를 사용하는 경우, TCP에서 timeout이 자주 발생하게 되어 결과적으로 시스템의 처리량(throughput)이 크게 떨어진다. 논문의 분석은 크게 두 부분으로 구성된다. 첫 번째 부분에서는 서버에서 전송되는 TCP 패킷들을 여러 집단으로 나누어 ‘패킷 그룹’이라 정의하고 각각의 패킷 그룹들이 AMC를 사용하는 무선 채널에서 전송되는 시간의 분포를 구하였다. 두 번째 부분에서는 첫 번째 부분의 결과를 토대로 embedded Markov chain을 이용해 TCP timer와 무선 전송을 모델링 하였다. 이 논문의 결과는 AMC를 사용하는 고속 순방향 데이타 전송 시스템인 HSDPA, 1xEV-DO, 1xEV-DV등의 설계와 운영에 지침이 될 수 있을 것이다.

• 한국운동역학회지
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• 제15권2호
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• pp.93-102
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• 2005

The purpose of this study was to examine the effect of step length on the joint moment. The subjects were 4 undergraduate and graduate students in their 20s with normal legs. The subjects were individually tested by the running timer at the walking speed of 0.67m/s, 134m/s, and 2.46m/s. The step length was regulated to -10% of normal, normal and +10% of normal step length using foot print. The walking performances of each subjects were filmed using a high speed video camera. The raw data were analyzed by LabVIEW Graphical Program and these data were analyzed by ANOVAs and Scheffe. The results of this study were as follows: The maximum dorsiflexion moment of the ankle joint increased as the step length increased only at the fast walking speed. Although there wasn't significant difference shown in the plantar flexion moment, regular pattern in the plantar flexion moment which increased as the step length increased was found. The first maximum extension moment of the knee joint increased only at the normal walking speed, but there appeared no significant difference in the maximum flexion and second extension moment. The maximum extension moment of the hip joint increased at the normal and fast walking speed. Although there wasn't significant difference, regular pattern in flexion moment which increased as the step length increased was found.