• Nuclear Engineering and Technology
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• v.13 no.4
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• pp.264-276
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• 1981

A simulation procedure which can represent time-dependent nuclear characteristics of TRIGA Mark-III reactor is developed. CITATION, a multi-group diffusion-depletion program, has been utilized as calculational tool. The group structure employed in this study consists of 7 groups: -3-fast and 4-thermal-which is conventionally utilized in TRIGA type reactor analysis. Three-dimensional nuclear characteristics are synthesized by combining results from two-dimensional plane calculation and two-dimensional cylinder calculation, since direct three-dimensional approach is not yet possible. An effort ia made to develope a method which can extract effective zone and group dependent bucklings by neutron diffusion theory rather than conventional zone and/or group independent Ducklings by neutron transport theory, since neutron leakage is quite high for small core such as research reactors. It is turned out that the method developed in this study gives satisfactory results. The calculation is performed under assumptions that all control rods are fully withdrawn, that no samples are inserted in the irradiation holes and that the core is located in the center of the reactor pool. Burnup-dependent variation of core excess reactivity, time dependent change of Xe-135 poisoning and reactivity worth of rotary specimen rack are calculated and compared with operation records. Neutron flux and power distribution as well as neutron spectrum in each irradiation .facility are presented.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.258-267
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• 2017

The price competitiveness of photovoltaic system (PV system) has risen recently due to the growth of industries, however, it is rarely applied to the greenhouse compared to other renewable energy. In order to evaluate the application of PV system in the greenhouse, power generation and optimal installation area of PV panels should be analyzed. For this purpose, the prediction of the heating and cooling loads of the greenhouse is necessary at first. Therefore, periodic and maximum energy loads of a multi-span greenhouse were estimated using Building Energy Simulation(BES) and optimal installation area of PV panels was derived in this study. 5 parameter equivalent circuit model was applied to analyzed power generation of PV system under different installation angle and the optimal installation condition of the PV system was derived. As a result of the energy simulation, the average cooling load and heating load of the greenhouse were 627,516MJ and 1,652,050MJ respectively when the ventilation rate was $60AE{\cdot}hr^{-1}$. The highest electric power production of the PV system was generated when the installation angle was set to $30^{\circ}$. Also, adjustable PV system produced about 6% more electric power than the fixed PV system. Optimal installation area of the PV panels was derived with consideration of the estimated energy loads. As a result, optimal installation area of PV panels for fixed PV system and adjustable PV system were $521m^2$ and $494m^2$ respectively.

• Journal of Life Science
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• v.14 no.5
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• pp.778-787
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• 2004

Effect of the microbial product made of Bacillus stearothermophilus DL-3, which was isolated from the soil and identified in this study, and rice bran on microorganisms in soil and growth of lettuce (Red skirt lettuce) and Chinese cabbage (Ga rack new No.1 Chinese cabbage) was investigated. Total numbers of microorganisms in the pot with untreated soil, treated with standard amount of microbial product and treated with double amounts of microbial product for growth of lettuce after 6 weeks were 2.78${\times}$10$^{7}$ CFU/g, 2.72${\times}$10$^{8}$ CFU/g and 3.63${\times}$10$^{8}$ CFU/g. Total numbers of microorganisms in the soil without treatment of microbial product and treated with standard amount of microbial product were 2.06${\times}$10$^{8}$ CFU/g and 5.49${\times}$10$^{8}$ CFU/g. Total numbers of microorganisms in the pot with untreated soil, treated with standard amount of microbial product and treated with double amounts of microbial product for growth of Chinse cabbage after 6 weeks were 1.43${\times}$10$^{7}$ CFU/g, 3.42${\times}$10$^{8}$ CFU/g and 7.22${\times}$10$^{8}$ CFU/g. Total numbers of microorganisms in the soil without treatment of microbial product and treated with standard amount of microbial product were 5.75${\times}$10$^{8}$ CFU/g and 7.96${\times}$10$^{8}$ CFU/g. On basis of leaf length, leaf width, leaf number, wet weight and dry weight, the growth of lettuce and Chinese cabbage on the soil treated with microbial product was faster than that on the untreated soil. The treatment of microbial product in the soil resulted in the increase of useful microorganisms, which seemed to enhance the growth of lettuce and Chinese cabbage.

• Journal of the Korea Society of Computer and Information
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• v.16 no.1
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• pp.163-173
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• 2011

In this paper, we propose a new paradigm of augmented reality board game environment and a portable game assistant(PGA) which can help gamers with strategy information. Previous AR board games consist of a private and public space. The public space provides rules of the game and shows the scene of game. And the gamers control game pieces in the public space. The previous games use the RFIDs for recognizing positions of the pieces, and the VR/AR environment for providing the scene of the game. However the RFIDs are expansive, and the VR/AR environment is inconvenient because it uses additional devices: the DataGlove, the digital pen, and the HMD. The proposed system recognizes positions of real pieces using the computer vision technique, and uses a monitor to provide dynamic effects. In the private space, previous systems provide entire screen of game and position of specific pieces, but cannot be controled the pieces by gamers. Therefore, in this system, we provide PGA that helps the user to plan of the strategy individually using universally mobile. The PGA helps to plan the strategy in the individual area, and to play easily in the side of the user's convenience.

• Journal of Gastric Cancer
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• v.7 no.2
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• pp.67-73
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• 2007

Purpose: There have been several comparative studies that have focused on elderly groups of patients with gastric cancer. However, new criteria are needed for this elderly group because of the longer life span of Korean people. The diagnosis of gastric cancer has sometimes been missed in the young age group. The perioperative risk is high in the elderly age group because of their combined diseases. This study was designed to determine the differences of the clinicopathologic features and the prognosis between young and elderly patients with gastric cancer. Materials and Methods: Eighty patients were divided in two groups and these patients were selected for making comparison between young and elderly groups of patients with gastric cancer. The young age group consisted of 31 patients who were aged 35 years old or less. The elderly age group was made up of 49 patients who were aged 75 years old or above. Results: For the clinicopathologic features, the young age group was characterized by a high incidence of the poorly differentiated type of adenocarcinoma and the diffuse type too, according to the Lauren classification. On the other hand, the elderly group was characterized by a high incidence of poorly to moderate differentiated adenocarcinoma and also the intestinal type according to the Lauren classification. The other clinical differences were unremarkable. Additionally, there was no survival advantage in the young age group compared to the elderly group. Conclusion: There were no clinicopathologic and prognostic differences between both extreme age groups. So, active surgical treatment is recommended even for the elderly patients group.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.4
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• pp.659-666
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• 2006

Servo-motors are used as key components of automated system by performing precise motion control as accurate positioning and accurate speed regulation in response to the commands from computers and sensors. Especially, the linear brushless servo-motors have numerous advantages over the rotary servo motors which have connection with the friction induced transfer mechanism such as ball screws, timing belts, rack/pinion. This paper proposes an estimation method of unknown motor system parameters using the informations from the sinusoidal driving type linear brushless DC motor dynamics and outputs. The estimated parameters can be used to tune the controller gain and a disturbance observer. In order to meet this purpose high performance Digital Signal Processor, TMS320F240, designed originally for implementation of a Field Oriented Control(FOC) technology is adopted as a controller of the liner BLDC servo motor. Having A/D converters, PWM generators, rich I/O port internally, this servo motor application specific DSP play an important role in servo motor controller. This linear BLDC servo motor system also contains IPM(Intelligent Power Module) driver and hail sensor type current sensor module, photocoupler module for isolation of gate signals and fault signals.

• The Korean Journal of Mycology
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• v.41 no.2
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• pp.67-73
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• 2013

Microbial diversity of soil samples from ancient stone-lined tombs was investigated. The tombs, discovered at Eoryung Ocheon-Ri site, Korea, were estimated to be belonged to middle class people from an ancient country, Gaya, which existed till AD 559 at the southern part of Korea. Nine fungal stains and 70 bacterial strains were isolated from the twelve soil samples, which were collected from the tomb Nos. 5 and 6. Ribosomal DNA sequence analysis discovered 5 fungal and 22 bacterial strains belonged to 10 genus groups from the tomb No. 5 while 1 fungal and 28 bacterial strains belonged to 6 genus from the tomb No. 6. The higher microbial diversity suggests that the tomb No. 5 was constructed warmer season than the tomb No. 6. Moreover, the discovery of Staphylococcus warneri, which is found as part of the skin flora on human and animals, and Bacillus aquimaris, which is a marine bacterium and can be discovered from tidal flat, from the surface of large dagger suggests that the ancient people may use meat and seafood at the burial ceremony.

• Journal of Sensor Science and Technology
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• v.1 no.2
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• pp.107-116
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• 1992

The optimum base material was selected by the thermal decomposition temperature of $CH_{3}CN$ on the surface of various metal oxides, and the FT-IR analyses of its products. On the surface of $SnO_{2}$, $CH_{3}CN$ was initiated to decompose at $130^{\circ}C$ and produced a lot of products at $200^{\circ}C$. The products from the reaction were found to be $H_{2}O$, $NH_{3}$ and CO, but $N_{2}O$ has started to produce at $320^{\circ}C$. The sensing characteristics of $SnO_{2}$ sensor to $CH_{3}CN$ are influenced by the absorbed species which are produced by the oxidation reaction of $CH_{3}CN$ on the surface of metal oxide. The gaseous species produced from the surface of sensing material in the oxidation reaction were found to be CO, $NH_{3}$, $H_{2}O$ and $NO_{x}$ etc.. It was assumed that the amount of $NO_{x}$ play a great role to the determining sensing properties. In the condition of 170 ppm $CH_{3}CN$, the sensitivity and optimum operating temperature of $SnO_{2}$ were 70% and $300^{\circ}C$, respectively. In this research, the response time of $CH_{3}CN$ to $SnO_{2}/Al_{2}O_{3}/Pd$ sensor added with 0.2 wt % Pd was found about 10 sec and sensitivity was also found relatively high.

• Korean Journal of Food Science and Technology
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• v.1 no.1
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• pp.51-61
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• 1969

In order to eliminate the considerable loss of rice by insects, to protect the human body from toxin excreted by some microbes, and to promote the storage efficiency of rice by employing the irradiation, the following experiments were carried out. Two varieties of rice, Paldal and Nongkwang polished and unpolished by the conventional methods and were packaged in polyethylene bags. After irradiating to the doses of 6-400 Krad of gamma-radiation from a $Co-^{60}$ source the samples were stored at the room temperature $20^{\circ}C$ for 8 months. The effects of radiation in terms of the removal of insects and microbes and the changes of chemical components (such as moisture, amylose, free sugar, and rancidity) were determined monthly from march to October during the storage. 1) Infestation of insects was greatly influeneed by the packaging materials used. There was no infestation in rice being packaged in a polyethylene bag, while as the rice packaged in a straw sack was infested in two months of the storage. 2) Some yeast and molds survived 400 K rad of radiation. Sterilizing dose to inhibit reproduction and growth of microbes was presumed to be higher than 400 K rad. Yeast mainly were found on the surface of rice, but mold were embeded into rice kernels by mycelium. 3) Changes of moisture contents during storage was not affected by radiation but was by humidity of the storage room. 4) Amylose content in starch increased with increasing dose of radiation and with the length of storage time, indicating possible depolymerization of starch molecules. 5) Free reducing sugar content was not affected by radiation and decreased with storage time. 6) Rancidity also increased with does and storage time.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.5
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• pp.51-60
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• 2015

In Korea, 69.4 % of duck farms had utilized conventional plastic greenhouses. In this facilities, there are difficulties in controlling indoor environments for raising duck. High rearing density in duct farms also made the environmental control difficult resulting in getting more stressed making their immune system weaker. Therefore, a facility is needed to having structurally enough solidity and high efficiency on the environmental control. So, new design plans of duck house have recently been conducted by National Institute of Animal Science in Korea. As a study in advance to establish standard, computational fluid dynamics (CFD) was used to estimate the aerodynamic problems according to the designs by means of overall and regional ventilation efficiencies quantitatively and qualitatively. Tracer gas decay (TGD) method was used to calculate ventilation rate according to the structural characteristics of duck houses including installation of indoor circulation fan. The results showed that natural ventilation rate was averagely 164 % higher than typically designed ventilation rate, 1 AER ($min^{-1}$). Meanwhile, mechanically ventilated duck houses made 81.2 % of summer ventilation rate requirement. Therefore, it is urgent to develop a new duck house considering more structural safety as well as higher efficiency of environmental control.