• Journal of Bio-Environment Control
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• v.25 no.3
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• pp.139-145
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• 2016

The objective of this study was to compare the growth and light use efficiency of red leaf lettuce grown under three types of combined light-emitting diodes (LEDs) and fluorescent lamps (FL) in a closed-type plant production system. The eighteen days-old lettuce seedlings of red leaf lettuce (Lactuca sativa L., 'Jeokchima') were transplanted to the close-type plant production system equipped with three types of combined LEDs with red (R, 655 nm), blue (B, 456 nm), green (G, 515 nm), and white (W, 456 nm + 558 nm) (R:B=8:2, R:W:B=8:1:1, R:G:B=8:1:1) and FL. The seedlings were grown under normal growth conditions ($20^{\circ}C$, $181{\pm}4{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, 12 h photoperiod) for four weeks. Lettuce plants grown under FL had significantly higher leaf shape index than those under all LED treatments. Although growth of shoots and roots was not show any significant difference among LED treatments, all of the LED treatments induced about 34% higher shoot fresh weight than that of the FL. On the other hands, the total power consumption of FL was 145 kW for 4 weeks, while the mean value of LED treatments was 54 kW, which was about 3 times lower value than that of the FL. The light use efficiency based on dry matter in LED treatments was about 34 mg/W and this was about 3.5 times higher energy saving value than the FL. In conclusion, this study showed that irradiation of optimal combined LEDs in closed-type plant production systems can improve the lettuce growth as well as maximize in light use efficiency through energy saving than the FL.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.842-846
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• 2016

It's possible for a human to breathe under water, but the amount of dissolved oxygen in the water is small and a large amount of water is necessary to obtain sufficient dissolved oxygen from water. So, large separation system with large water pumps, having large surface areas, and large battery sources are needed. Exhalation gases are used to solve this problem. Theses gases contain some oxygen, nitrogen, and carbon dioxide; they contain less oxygen and more carbon dioxide compared to air. Therefore, reduction of the amount of carbon dioxide is necessary. If exhalation gases are employed appropriately, the separation device can be made more compact. Inlet water mixed with exhalation gases is supplied into the separation device, and dissolved gases are separated from the mixed water as it passes through the device. The inlet part of a typical separation system with a water delivery pump before the membrane module has more than one atmosphere. Hence, a compressor is used to mix the exhalation gases. In this study, the pressure at the inlet due to the use of a suction pump after the membrane module was less than one atmosphere; hence, compressors were not required. Separation characteristics were studied using a separation device without a compressor. The use of exhalation gases led to an increase in the amount of dissolved gases being separated. As the amount of inlet exhalation gases was increased, the separation of dissolved gases was increased as well.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.812-817
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• 2016

This paper dealt with electrical and optical requirements of naval vessel's LED luminaires. And the products have been tested to determine whether the products meet these requirements or not. This study analyzes the cost-effectiveness of the LED luminaires which have been implemented for the application to naval vessel since 2012. The LED requirements were proposed based on comparison among other standards/specifications such as Korean Industrial Standard(KS), Korean Defense Specification(KDS) and US Navy Military Specification(MIL). Application of the proposed requirements were then be verified by analyzing and testing the electrical and optical characteristics of both fluorescent Luminaires and LED luminaires, and the LED luminaires were installed to A1 naval vessels according to the proposed requirements. As results, approximately 40% of power consumption was saved by using LED luminaires compared to using fluorescent luminaires while luminous flux was increased by 10~15%. Moreover, using LED luminaires of the proposed requirements exhibited the effect of reducing approximately 4,900 fluorescent luminaires in 10 naval vessels in the time period between 2012 to 2015, which is equivalent to cost reduction of \0.56M approximately. Such cost reduction is further expected considering the LED luminaires will continue to be applied to naval vessels in the future.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.836-841
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• 2016

An indoor positioning system using Wi-Fi is essential to produce a radio map that combines the indoor space of two or more dimensions, the information of node positions, and etc. in processing for constructing the radio map, the measurement of the received signal strength indicator(RSSI) and the confirmation of node placement information counsume substantial time. Especially, when the installed wireless environment is changed or a new space is created, easy installation of the node and fast indoor radio mapping are needed to provide indoor location-based services. In this paper, to reduce the time consumption, we propose an algorithm to distinguish the straight and curve lines of a corridor section by RSSI visualization and Sobel filter-based edge detection that enable accurate node deployment and space analysis using cable-type Wi-Fi node installed at a 3 m interval. Because the cable type Wi-Fi is connected by a same power line, it has an advantage that the installation order of nodes at regular intervals could be confirmed accurately. To be able to analyze specific sections in space based on this advantage, the distribution of the signal was confirmed and analyzed by Sobel filter based edge detection and total RSSI distribution(TRD) computation through a visualization process based on the measured RSSI. As a result to compare the raw data with the performance of the proposed algorithm, the signal intensity of proposed algorithm is improved by 13.73 % in the curve section. Besides, the characteristics of the straight and the curve line were enhanced as the signal intensity of the straight line decreased by an average of 34.16 %.

• Plant Journal
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• v.14 no.3
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• pp.35-41
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• 2018

Considering the recent government policy toward North Korea and situation of power facilities in North Korea, it will be necessary to prepare for the consumption of the anthracite coal from Korea in coal-fired power plants. In this study, the anthracite co-fired tests in 500 MW thermal power plants were conducted with varying the main operation conditions, such as anthracite injection position in the boiler, coal fineness and combustion air flow, to investigate the effects on the generation of unburned carbon. It was confirmed that the generation of unburned carbon was remarkably reduced when the anthracite coal was injected into the boiler low burner with a relatively long residence time in the main combustion region, and that the increase of the coal fineness proportional to the combustion reaction surface area also reduces the generation of unburned carbon. An increase in the combustion air flow, which increase the combustion reactivity, also contributes to the reduction of unburned carbon. It is possible to maintain the unburned carbon generation below 5 % of the ash recycling quality by controlling the above operating conditions for the given mixing rate of anthracite, and the priority of changing the operating conditions within the test range is the highest for anthracite coal injection position.

• Spatial Information Research
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• v.19 no.6
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• pp.11-18
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• 2011

Urban space is the main contributor of greenhouse gas emissions, a primary cause of global warming. In order to reduce greenhouse gas emissions, planning at a city-level is necessary. The aim of this research is to develop a carbon emission model which can be used to create and manage urban spaces. In order to achieve this aim, the following methodologies were utilized. First, urban planning criteria related to population, landuse, and activity level were selected through theoretical speculation. Second, carbon dioxide emission was calculated based on electricity, gas energy, heating, petroleum, and water usages. Third, Seoul was selected as a case study city, and a carbon emission model was developed through a relational analysis between Seoul's urban planning criteria and carbon emissions. Thus far, various efforts have been made to respond to climate changes in urban spaces, but these have been limited to analyzing contributing factors in terms of their total amounts of carbon emissions in the entire city. However, the carbon emission model of this study is derived from urban planing criteria at a detailed scale. This sets our study apart from other studies by demonstrating a specific model in a local setting which can be utilized for lowering carbon emissions at a city level.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.2
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• pp.7-13
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• 2011

This paper presents a Time-to-Digital Converter which is a key block of an All-Digital Phase Locked Loop. In this work, a Vernier Delay Line is added in a conventional Gated Ring Oscillator, so it could get multi-phases and a high resolution. The Gated Ring Oscillator uses 7 unit delay cell, the Vernier Delay Line is used each delay cell. So proposed Time-to-Digital Converter uses total 21 phases. This Time-to-Digital Converter circuit is designed and laid out in $0.13{\mu}m$ 1P-6M CMOS technology. The proposed Time-to-Digital Converter achieves 26ps resolution, maximum input signal frequency is 100MHz and the digital output of proposed Time-to-Digital Converter are 8-bits. The proposed TDC detect 5ns phase difference between Start and Stop signal. A power consumption is 8.4~12.7mW depending on Enable signal width.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.106-106
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• 1999

반도체 소자가 소브마이크론 이하로 집적화 되어감에 따라, RC 신호 지연 및 간섭 현상, 전력 소비의 증가 문제가 심각하게 대두되고 있다. 이러한 문제를 개선하기 위해서는, 현재 층간 절연막으로 상용화되어 있는 SiO2 박막을 대체할 저유전율 박막의 개발이 필수적이며, 많은 연구자들이 여러 가지 새로운 유기물질과 무기물질은 제안하고 있다. 반도체 공정상의 적합성을 고려할 때, 이들 여러물질 중에서 알킬기를 함유한 SiO2 박막(이하 'Si-O-C-H 박막'으로 표기)에 많은 관심이 집중되고 있다. Si-O-C-H 박막은 알킬기에 의해 형성된 나노 스케일의 기공에 의해 작은 유전율을 가지게 된다. 따라서, 박막내의 알킬기의 함유량이 많을수록 보다 작은 유전율을 얻을 수 있다. 그러나 과다한 알킬기의 함유는 Si-O-C-H 박막의 열적 특성을 열화시키는 부정적인 효과도 있다. 본 연구에서는 bis-trimethylsilylmethane(BTMSM, H9C3-Si-CH2-Si-C3H9) precursor를 이용하여 Si-O-C-H 박막을 증착하였다. BTMSM precursor의 중요한 특징중 하나는, 두 실리콘 원자 사이에 Si-CH2 결합이 존재한다는 사실이다. Si-CH2 결합은 양쪽의 Si에 의해 강하게 결합되어 있어서, BTMSM precursor를 사용하여 Si-O-C-H 박막은 유전상수도 작을 뿐 아니라, 열적으로도 안정된 특성이 얻어질 것으로 기대된다. Si-O-C-H 박막의 열적 안정성을 평가하기 위하여, 고온 열처리 전후의 FT-IR 스펙트럼 분석과 C-V(capacitance-voltage) 측정에 의한 유전상수 변화를 살펴보았다. 또한 증착된 박막의 미세구조 및 step coverage 특성 관찰을 위하여 SEM(scanning electron microscopy) 및 TEM(transmission electron micfroscopy) 분석을 하였다. 변화하였으며 이는 포토루미네슨스의 변화의 원인으로 판단된다. 연구하였다. CeO2 와 Si 사이의 계면을 TEM 측정에 의해 분석하였고, Ce와 O의 화학적 조성비를 RBS에 의해 측정하였다. Si(100) 기판위에 증착된 CeO2 는 $600^{\circ}C$ 낮은 증착률에서 seed layer를 하지 않은 조건에서 CeO2 (200) 방향으로 우선 성장하였으며, Si(111) 기판 위의 CeO2 박막은 40$0^{\circ}C$ 높은 증착률에서 seed layer를 2분이상 한 조건에서 CeO2 (111) 방향으로 우선 성장하였다. TEM 분석에서 CeO2 와 Si 기판사이에서 계면에서 얇은 SiO2층이 형성되었으며, TED 분석은 Si(100) 과 Si(111) 위에 증착한 CeO2 박막이 각각 우선 방향성을 가진 다결정임을 보여주었다. C-V 곡선에서 나타난 Hysteresis는 CeO2 박막과 Si 사이의 결함때문이라고 사료된다.phology 관찰결과 Ge 함량이 높은 박막의 입계가 다결정 Si의 입계에 비해 훨씬 큰 것으로 나타났으며 근 값도 증가하는 것으로 나타났다. 포유동물 세포에 유전자 발현벡터로써 사용할 수 있음으로 post-genomics시대에 다양한 종류의 단백질 기능연구에 맡은 도움이 되리라 기대한다.다양한 기능을 가진 신소재 제조에 있다. 또한 경제적인 측면에서도 고부가 가치의 제품 개발에 따른 새로운 수요 창출과 수익률 향상, 기존의 기능성 안료를 나노(nano)화하여 나노 입자를 제조, 기존의 기능성 안료에 대한 비용 절감 효과등을 유도 할 수 있다. 역시 기술적인 측면에서도 특수소재 개발에 있어 최적의 나노 입자 제어기술 개발 및 나노입자를 기능성 소재로 사용하여 새로운 제품의 제조와 고압 기상 분사기술의 최적화에 의한 기능성 나노 입자 제조 기술을 확립하고 2차 오염 발생원인 유기계 항균제를 무기계 항균제로 대

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.2B
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• pp.100-107
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• 2007

Recently, a study of BcN(Broadband convergence Network) is progressing continuously, and it is important to improve the quality of the service according to subscribers because a scale of network is about to be larger. It is more important to manage QoS(Quality of Service) of all subscribers in layer 2 than layer 3 network since managing it in layer 3 network cost both additional processes and large hardware. Moreover, QoS based on Best-Effort service has been developed because tots of subscribers should use limited resource in BcN. However, they want to be supplied with different service even though they pay more charge. Therefore, it is essential to assign the different bandwidth to subscribers depending on their level of charge. The method of current Rate Limiter limits the bandwidth of each port that does not offer fair service to subscribers. The Rate Limiter proposed in this paper limits bandwidth according to each subscriber. Therefore, subscribers can get fair service regardless of switch structure. This new Rate Limiter controls the bandwidth of subscribers according to the information of learning subscriber and manages maximum performance of Ethernet switch and QoS.

• Journal of Korean Society of Forest Science
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• v.99 no.4
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• pp.597-602
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• 2010

The most basic matter to establish forest carbon circulation village is statistic on greenhouse gas emissions. But currently, although there is statistic on greenhouse gas emissions in the level of city or province, there is not statistic on greenhouse gas emission in village unit. According to the results, The model area is located in Seobyeok-ri, Chunyang-myeon, Bonghwa-gun, Gyeongsangbuk-do, the total $CO_2$emissions caused by energy used in the model area was $1,755tCO_2$. Heating accounts for 55% of total emissions followed by 23% for power and 22% for vehicles. The model area emitted $572tCO_2$ due to rice growing and livestock raising, accounting for approximately 24.5% of total $CO_2$ emissions. It is expected that a reduction of as much as $884tCO_2$ emissions will be made from the current $964tCO_2$ to a level of 1/12th that amount, or $80tCO_2$ by replacing heating energy currently used in the model area with wood bioenergy such as wood chips or pellets. In addition, carbon emission reduction is expected for both heating and power by replacing the power consumption in houses, buildings, and street lights with solar power.