• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4197-4203
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• 2013

In order to investigate the heating performance of multi-heat pump applying an inverter compressor, the experiment on heat pump with 3 indoor units was performed under the heating standard and heating low-temperature conditions. The performance data of heat pump with 3 indoor units were measured by the multi-psychrometric calorimeter. The operation characteristics and the behavior of the refrigerant cycle of the heat pump with 3 indoor units were understood from the heating capacity, heating COP, and P-h diagram by indoor-unit combination. The present experimental results show that the operating load and performance of the multi-heat pump depends on the indoor-unit combination. The heating capacity and heating COP of the low temperature condition were smaller than those of the standard one. Also the refrigerant cycles on indoor-unit combination were analyzed by using P-h diagram.

• Nuclear industry
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• v.16 no.2 s.156
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• pp.29-38
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• 1996

울진 1호기는 88년 9월 상업운전을 시작한 이래 96년 1월 현재 약 320다발의 사용후연료가 인출되어 연료저장조에 저장되어 있다. 이 저장량은 기존의 허용저장용량을 초과하는 양으로서 초과분은 지난해 3월 설치한 임시 저장대에 저장해 왔다. 최근 울진원자력본부에서는 현재 사용중인 저장조의 저장능력을 가능한 한도까지 확장하기 위해 기존 저장대를 고밀도 저장대로 교체$\cdot$설치하여, 2008년까지 발생되는 사용후연료를 저장할 수 있도록 하였다. 본 공사는 사용후연료 저장조에 고방사선 준위의 사용후연료가 저장되어 있는 상태에서 수행된 국내 최초의 공사로서, 수중작업을 수상작업으로 작업방법을 변경$\cdot$수행하였다. 그 추진경위와 의의 등을 살펴본다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11a
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• pp.248-253
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• 1996

한국원자력연구소에서는 최고 16MPa애서 운전할 수 있는 RCS 열수력 Loop를 저작하고 CHF 측정실험을 수행하고 있다. 본 연구에서는 저유량조건에서 압력이 CHF에 미치는 영향을 조사하기 위해 압력 12MPa, 질량유속 300~550kg/$m^2$.s, Test Section입구 과냉도 210 kJ/kg의 범위에서 CHF 실험을 수행하였다. 본 실험조건에서 CHF는 환상류영역에서 발생하였으며 발생기구는 Entrainment-Limited CHF가 지배적이었다. Doerffer의 CHF 상관식은 저압에서 예측능력이 현저하게 떨어지나 고압조건에서는 실험자료를 잘 예측하였다. Bowring의 상관식은 고압 및 저압에서도 양호한 예측능력을 보여주었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.3
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• pp.587-592
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• 2008

In order to investigate the performance of an internal heat exchanger for $CO_2$ refrigerant system, the experiment was performed. Four kinds of internal heat exchangers(IHX) were used. The effects on the IHX length, the number of tube, the operating condition and the type of IHX were investigated. With increasing of the IHX length, the capacity and efficiency increased. The pressure drop of the low-side was larger compared with that of the high-side. As the temperature of the gas cooler increased, the capacity and efficiency increased linearly. The operation condition of evaporator was suggested as two phase region rather than superheat region. The capacity and efficiency of the micro-channel was larger about 90% and 75% than those of the tube. But the pressure drop of the micro-channel was more larger, compared with that of the tube.

• Science of Emotion and Sensibility
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• v.21 no.2
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• pp.29-42
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• 2018

As information technology is more actively incorporated into automobiles, the role of IVIS (In-Vehicle Infotainment System) is becoming increasingly important for providing convenience and entertainment for drivers. However, using the infotainment systems while driving requires task switching and attending to two visual resources simultaneously. We simulated a setting where participants have to drive while interacting with the infotainment system and examined how task difficulty and motor cues impact driver task-switching and driving performance, specifically whether the effects of motor cues differ depending on task difficulty. For the infotainment display, we used two types of number array depending on the congruency between the digit repetition and the chunking unit, while task difficulty was manipulated by the size of the touch-keys. Participants were instructed to dial two numbers on the screen while we recorded the dialing time, lateral position, inter-key press intervals, and steering wheel control. We found that dialing time and lateral position were affected by task difficulty, while the type of number array had no effect. However, the inter-key press intervals between chunked numbers and steering wheel movement both increased when participants had to use an incongruent number array, which indicates that, if number digits are repeated, chunking is ignored by the drivers. Our findings indicate that, in a dual-task condition, motor cues offset the effect of chunking and can effectively signal the timing for task switching.

• Journal of the Korea Society of Computer and Information
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• v.26 no.11
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• pp.191-199
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• 2021

This study aims to present the need to supplement the driver's license renewal test for elderly drivers. In Korea, the proportion of elderly drivers is increasing as the elderly population increases rapidly. Overall the traffic accident rate is decreasing but the traffic accident and death rate from traffic accidents are increasing in older drivers. In this study the assessments and education conducted when renewing the driver's license for elderly drivers conducted in Korea were conducted to find out the necessary tests compared to the current situation of foreign countries. Although it is appropriate to evaluate the three key functional areas of vision, cognition, motor and somatosensory, we currently evaluate visual acurity in vison area. While MMSE-K and Clock drawing tests are not recognizable for mild cognitive impairment in cognitive areas. The motor and somato sensory function to perform driving are not evaluated at all. Therefore for safe driving of older drivers, the test to be conducted during renewal of the driver's license will need to supplement that the visual field and contrast sensitivity in vision area, cognitive function from mild cognitive impairments, and the endurance, functional range of motion and proprioception in motor function area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.293-302
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• 2019

This study systematically analyzed computer-based driving intervention programs for seniors, to provide the academic background for driving intervention for seniors. Articles published from January 2009 till December 2018 were researched and analyzed. 'PubMed, Google Scholar, and Science Direct' were used to search articles published overseas, and 'RISS, KERIS, and KISS' searched for articles published in Korea. Based on the inclusion and exclusion criteria, totally 359 papers were retrieved, and 10 articles were finally analyzed; 8 articles (80%) were evidence level I, and 2 articles (20%) were evidence level III. Amongst the computer-based interventions, driving simulators (70%) were the most common, followed by two video image training (20%) and one Nintendo Wii program (10%). In most studies, driving simulators trained the cognitive and visual abilities of seniors and enhanced their abilities to cope with risk situations under various simulated circumstances. Other interventions were also reported to have a positive effect. For evaluating elderly drivers, the driving performance evaluation using a driving simulator was the most common; in addition, evaluations of attention, space-time ability, cognitive function, risk perception, depression and anxiety were also commonly used. We believe that it is appropriate to employ computer-based driving intervention programs for seniors to train and evaluate various domains. We expect that these interventions can be used as an effective tool for safe driving.

• International Journal of Highway Engineering
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• v.10 no.4
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• pp.127-138
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• 2008

Vehicles have recently become one of the main factors affecting our quality of life, and the needs of vehicles are still increasing. As a result, the growth of vehicles generate more crashes every year. One main factor for vehicle crashes is uncareful driving behaviors. Especially, drowsy or fatigue driving behaviors explain about 10-20% of the crashes, and they cause serious results because of the delay of response time and the decrease of object-recognition. Therefore, this research conducted real time image processing tests in order to study how cellular phone usages and drowy(or fatigue) drives affect driving behaviors. A vehicle simulator was used for this research, and the faceLAB 4.5 of Seeing Machines for eye image tracking tests using a small camera was installed in the front of the simulator, and normal and drowsy(or fatigue) driving patterns were analyzed.

• Electronics and Telecommunications Trends
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• v.23 no.1 s.109
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• pp.153-162
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• 2008

HUD 기술은 항공기 조종사의 시계확보와 조종 수행 능력 향상을 위하여 도입되었으나 최근에는 자동차 운전자의 운전 수행력을 높이고 안전 운전을 도모하기 위하여 차량에 도입되기 시작하였다. 하지만 HUD 기술이 실제로 일반 차량에 적용되고 관련 산업이 활성화되기 위해서는 현재의 기술개발 현황은 물론이고 관련 산업체의 기술개발 경쟁력, 활성화 정도, 성장 가능성에 대한 분석과 상용화를 위한 요구사항 및 애로사항에 대한 파악과 방안 마련이 우선적으로 수행되어야 한다. 따라서 본 고에서는 텔레매틱스 관련 각 산업계와의 심층 면접을 통하여 이러한 문제점들에 대한 산업 현장의 실질적인 현황을 파악하고 이를 토대로 HUD 기술이 텔레매틱스 분야에 성공적으로 적용되기 위해 필요한 방안을 도출해 본다.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.600-602
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• 1999

원자력발전 비율이 증가함에 따라 전기에너지의 효율적인 이용과 원자력발전의 경쟁력 제고를 위하여 원자력발전소(이하 원전)의 부하추종운전 필요성이 점점 커지고 있다. G7과제의 하나로 개발되고 있는 차세대원자로(KNGR, Korean Next Generation Reactor)는 경쟁력 있는 원전의 설계를 위하여 "일일부하추종운전 능력의 확보"를 기본 성능요건의 하나로 하여 개발되고 있다. 그러나 수동으로 원자로출력분포를 제어하는 기존 원전의 제어방식으로는 상기목표를 충족시키기 어려워 원자로의 출력분포와 출력을 동시에 제어하는 새로운 자동 제어방식을 도입하였다. 본 논문에 기술된 제어방법은 원자로 출력분포 상태에 따른 비선형 제어방법이 적용되며 목표출력 부근에서의 Oscillatory Behavior 방지를 위해 설정된 Deadband 내에서의 다른 상태변수를 제어하기 위한 알고리즘도 포함된다. 개발된 제어방법의 성능을 확인하기 위해 원자로 증기공급계통 전체를 모델링한 성능분석 Simulator를 이용한 Numerical Simulation을 수행하였다. 일일부하추종운전은 100-50-100%P[$(10{\sim}16)-2-(10{\sim}4)-2$ hr] power cycle over a 24-hour period, 주파수제어는 일반적인 Grid Follow에 대해 Simulation하였다.