• Nuclear Engineering and Technology
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• 제51권6호
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• pp.1532-1539
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• 2019

This paper analyzes a new method for reducing boiling water reactor fuel temperature during a Loss of Coolant Accident (LOCA). The method uses a device called Reverse Flow Restriction Device (RFRD) at the inlet of fuel bundles in the core to prevent coolant loss from the bundle inlet due to the reverse flow after a large break in the recirculation loop. The device allows for flow in the forward direction which occurs during normal operation, while after the break, the RFRD device changes its status to prevent reverse flow. In this paper, a detailed simulation of LOCA has been carried out using the U.S. NRC's TRACE code to investigate the effect of RFRD on the flow rate as well as peak clad temperature of BWR fuel bundles during three different LOCA scenarios: small break LOCA (25% LOCA), large break LOCA (100% LOCA), and double-ended guillotine break (200% LOCA). The results demonstrated that the device could substantially block flow reversal in fuel bundles during LOCA, allowing for coolant to remain in the core during the coolant blowdown phase. The device can retain additional cooling water after activating the emergency systems, which maintains the peak clad temperature at lower levels. Moreover, the RFRD achieved the reflood phase (when the saturation temperature of the clad is restored) earlier than without the RFRD.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1348-1351
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• 1996

In field bus network, field device are connected with a medium. Because a medium must be shared for transmitting data, there are random delay time when data arrive destination station. It is difficult that all data packets are guaranteed synchronization and real-time restriction. In this paper, we show an algorithm that makes network utilization to maximum, guarantees real-time restriction, calculates sampling time at all control loop.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.807-810
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• 2003

The PCI 2.2 spec introduces Delayed Transaction mechanism to improve system performance for target device with slow local bus. But this mechanism has some restriction since target device doesn't know prefetch data size. So, we propose a new mechanism, which target device prefetch exact data on local bus, to improve data rate on PCI or local interface. The simulation results showed that the proposed mechanism more improves system performance than the Delayed Transaction mechanism.

• 기술혁신연구
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• 제8권2호
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• pp.1-17
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• 2000

Recently, due to the primary emphasis of health industry and to the restriction of budget, setting the priorities for effective and efficient investment on the medical device and material products has been one of the critical issues in the government sector. This paper shows how an Analytic Hierarchy Process (AHP) model can be used for assessing selected medical device and material products for grant of the Ministry of Health & Welfare. The final results show that unabsorbable suture is the most attractive medical device product among 88 evaluated products, followed by IV cannula, central venous catheter.

• 한국유체기계학회 논문집
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• 제9권3호
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• pp.22-28
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• 2006

The discharge coefficient in segmental wedge haying ninety degrees yeller angle for the five kinds of opening ratio with differential pressure taps located at both upstream and downstream of one diameter of pipe was measured. Main purpose of this work is placed on specifying the characteristic of discharge coefficient of a segmental wedge used as a primary element of flow metering devices, and suggestion for the fixed location of pressure taps useful. Although the range of the opening ratio over this work is more expanded than previous studies. The opening ratios of segmental wedge, namely 0.3, 0.4, 0.5, 0.6 and 0.7 were investigated. The Reynolds number based on the spool inside diameter ranges from 12,000 to 380,000.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.396-401
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• 2017

In this paper, a device to analyze gait pattern was developed by using a 2-axis acceleration sensor attached to the foot. The 1st low-pass filter was adapted to limit the frequency band up to 5 Hz. An algorithm to detect the peak value exceeding the threshold voltage of an X-axis acceleration sensor and a Z-axis acceleration sensor was developed and normal and abnormal walking patterns were thus differentiated. Also, MCU and Bluetooth were combined to transfer the data to other MCUs to display on an LCD; the size of the device could then be reduced. The new algorithm and the device allowed the individual walking patterns to be easily measured at a low cost and with less restriction on activities compared to conventional multiple pressure sensors or motion camera system.

• 전기학회논문지
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• 제65권4호
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• pp.673-677
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• 2016

In this study, In order to measure foot pressure, it makes analyzing device using multi-pressure sensor. This device was limited frequency band to 5Hz by using low-pass filter and MCU was detected signal every milliseconds. After wearing the device, the result was confirmed by blue-tooth to measure wirelessly. Also, we propose an algorithm to obtain the walking pattern using a time table in each of the detected peak from the pressure sensor. Using the algorithm, right walking pattern and abnormal pattern was detected. The results can be reflected more individual walking patterns than when using a conventional methods and also, developed device was no restriction on the human activity.

• 산업기술연구
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• 제34권
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• pp.27-32
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• 2014

Infrared remote controllers are widely used in controlling electronic devices due to its simplicity and convenience. This paper presents a smart phone application unifying any infrared remote controllers. We can select a device from device list menu of the application. Any new device can be added easily by downloading the protocol file of the device from protocol file server. Remote controller protocol files are stored in audio file format, and the file related to a specific menu button is transmitted through the audio jack of smart phones. The protocol file server is a standard file server, and protocol files for various devices are collected by infrared receiver module. For smart phones without infrared facility, a small infrared module translating audio signal to infrared signal is applied.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.302-307
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• 2005

The discharge coefficient in segmental wedge having ninety degrees vertex angle for the five kinds of opening ratio with differential pressure taps located at both upstream and downstream of one diameter of pipe was measured main purpose of this work is placed on developing the proper form of an equation for the discharge coefficient of a segmental wedge used as a primary element of flow metering devices, and from thata six-term equation which can express the variability of opening ratios was developed. The same assumption and hypotheses were used and tested for all procedures as conventional differential producers; however, the range of the opening ratio over this work is more expanded than previous studies. The opening ratios of segmental wedge, namely 0.3, 0.4, 0.5, 0.6 and 0.7 were investigated the Reynolds number based on the spool inside diameter ranges from 12,000 to 380,000, the resulting equation for the discharge coefficient is relatively simple; it contains only one variable-opening ratio because the characteristic of discharge coefficient of segmental wedge has little connection with the Reynolds number as shown by previous studies.

• 한국정보통신학회논문지
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• 제11권11호
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• pp.2127-2134
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• 2007

전자적인 학습은 이동성 및 접근의 용이성, 즉시성, 유연성을 제공하여 학습자의 시간적인 제약을 극복할 수 있었으나 유선 컴퓨터상에서 공간에 의한 제약은 많은 문제로 남아있다. 따라서 이런 전자적인 학습은 학습자에게 시간과 공간적인 제약을 극복할 수 있는 모바일 학습 환경으로 변화하는 추세이다. 그러나 모바일 디바이스들은 작은 디스플레이 사이즈로 인하여 실시간 동영상에서 제공되는 학습 내용을 정확하게 인식하기는 어려운 실정이다. 따라서 본 논문은 실시간 학습 영상을 관심 영역에 대한 학습 영역을 추출하고 작은 디스플레이 디바이스 사이즈에 적절한 영상 크기로 축소하여 무선 PDA에 디스플레이하는 기법을 제안한다. 실험 결과, 다양한 강의 영상에서 학습 내용 중심의 영역을 적응적으로 추출하고, 사용자 디바이스 사이즈에 적합한 영역을 효과적으로 계산함으로써 계산에 소요되는 시간을 크게 줄일 수 있었다.