• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.645-648
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• 2009

According to development of Information Technology and generalization of internet, practical use field of geography information became various. Therefor various Geographic Information System (GIS) constructed to manage geography information efficiently. However, geography information data of various form is depending on graphic authorizing tool of various form being not normalized each other. So, OGC (Open Geospatial Consortium) proposed GML (Geography Markup Language) that describe normalized geography information data that can apply mutually and W3C proposed SVG (Scalable Vector Graphics) of vector base. In this paper creates GML data of XML base for geography information data processing to vector graphic object. and design and implementation of GML document editing and translation system that define code converter that create GML document through created graphic objects and change vector graphic to logic structure of XML base.

• Nuclear Engineering and Technology
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• v.22 no.1
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• pp.66-74
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• 1990

The thermal-hydraulic characteristics of the 17$\times$17 OFA (Optimized Fuel Assembly) used in the KNU 7&8 are analyzed and compared with that of the 17$\times$17 SFA (Standard Fuel Assembly) loaded in the KNU 5&6. The thermal-hydraulic characteristics analyzed are minimum DNBR, fuel centerline temperature and exit void fraction at normal operation and design over power transient. Additionally, local linear rod power, which will cause fuel centerline melting, is calculated. The DNBR sensitivity calculations are performed with respect to the reactor operating parameters. COBRA-IV-I code is used for these calculations. The modified W-3 correltion and the drift-flux model are applied for the critical heat flux calculation and the void fraction calculation, respectively. From the calculated results, it has been found that the possibility of DNB occurrence is higher in the OFA than in the SFA. The other hand, the local linear power resulting in fuel centerline moiling of the OFA is nearly equal to that of the SFA.

• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2184-2194
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• 2021

The Free-Piston Stirling engine (FPSE) is of interest for many research in aerospace due to its advantages of long operating life, higher efficiency, and zero maintenance. In this study, a 1-kW FPSE was proposed by analyzing the requirements of Space Reactor Power Systems (SRPS), of which performance was evaluated by developing a code through the Simple Analysis Method. The results of SAM showed that the critical parameters of FPSE could satisfy the designed requirements. The heater of the FPSE was designed with the copper rectangular fins to enhance heat transfer, and the parametric study of the heater was performed with Computational Fluid Dynamics (CFD) software STAR-CCM⁺. The Performance Evaluation Criteria (PEC) was used to evaluate the heat transfer enhancement of the fins in the heater. The numerical results of the CFD program showed that pressure drop and Nusselt number ratio had a linear growth with the height of fins, and PEC number decreased as the height of fins increased, and the optimum height of the fin was set as 4 mm according to the minimum heat exchange surface area. This paper can provide theoretical supports for the design and numerical analysis of an FPSE for SRPSs.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.563-575
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• 2020

The purpose of this study is to evaluate the activation characteristics that occur in a linear accelerator for container security inspection. In the computer simulation design, first, the targets consisted of a tungsten (Z=74) single material target and a tungsten (Z=74) and copper (Z=29) composite target. Second, the fan beam collimator was composed of a single material of lead (Z=82) and a composite material of tungsten (Z-74) and lead (Z=82) depending on the material. Final, the concrete in the room where the linear accelerator was located contained magnetite type and impurities. In the research method, first, the optical neutron flux was calculated using the MCNP6 code as a F4 Tally for the linear accelerator and structure. Second, the photoneutron flux calculated from the MCNP6 code was applied to FISPACT-II to evaluate the activation product. Final, the decommissioning evaluation was conducted through the specific activity of the activation product. As a result, first, it was the most common in photoneutron targets, followed by a collimator and a concrete 10 cm deep. Second, activation products were produced as by-products of W-181 in tungsten targets and collimator, and Co-60, Ni-63, Cs-134, Eu-152, Eu-154 nuclides in impurity-containing concrete. Final, it was found that the tungsten target satisfies the permissible concentration for self-disposal after 90 days upon decommissioning. These results could be confirmed that the photoneutron yield and degree of activation at 9 MeV energy were insignificant. However, it is thought that W-181 generated from the tungsten target and collimator of the linear accelerator may affect the exposure when disassembled for repair. Therefore, this study presents basic data on the management of activated parts of a linear accelerator for container security inspection. In addition, When decommissioning the linear accelerator for container security inspection, it is expected that it can be used to prove the standard that permissible concentration of self-disposal.

• Journal of Preventive Medicine and Public Health
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• v.7 no.1
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• pp.211-222
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• 1974

The survey was carried out on 1,031 primary school children for about 1 month, from June 1, to June 30, 1974, for the purose of understanding indirectly scio-medical status of a remote rural area, reflecting health status of primary school children. The summarized results were as follows: 1) The average age of surveyed children according to school year by sex was older in girls than in boys. The entrance in school at suitable age was peaked as 80.9% in boys of 5th school year and 72.4% in girls of 3rd school year, and also sunk 68.8% in boys of 2nd school year and 58.7% in girls of 1st school year. 2) Prevalence rate according to W.H.O. diseases classification during last a month and a year. a) During last month: The diseases of respiratory system remarked the highest 101.1 in boys and 116.6 in girls. The next were diseases of digestive system (24.2 in boys and 32.1 in girls), The girls were higher than boys in prevalence rate. b) During last year: The diseases of diegestive system ranked the highest 133.0 in boys and next, the diseases of respiratory system (108.6 in boys). c) Present illness: Number of code III ranked the highest 129.2 and next XII(127.3) in boys but inverted in girls such as XII(144.9) and III(116.7) and also, Number of code XVII was prevalenced twice in boys than in girls. d) Chief complaints by sex: Abdominal pain ranked the highest 71.2 per 1,000 population and next headache (34.7) in boys but headache ranked the heighest 88.5 and next abdominal pain (63.3) in girls. e) Water drinking habit: Number of code IX was higher in habit of raw water drinker than in habit of boiled water drinker and healthy children were higher in boiled water habit group than in raw water habit group. The diseases of respiratory system were the highest 124.74 in girls and next, the diseases of digestive system (52.3 in girls). According to school year, healthy children were increased to higher grades. 3) Average sick day per total surveyed children and patient during last month and last year. a) Per surveyed 1,031 children was 0.28 days during last month and 0.98 days during last year. And also per patient was 1.78 days during last month and 3.22 days during last year. b) Average sick day was higher in girls than in boys during last month, but inverted during last year. 4) Average absented day per total surveyed children and patient during last month and last year. a) Per surveyed 1,031 children were 0.43 days during last month and 3.81 days during last year (omitted 1st school year). b) Per absented children were 2.0 days during last month and 7.10 days during last year. c) Per absented children were 8.16 days in boys and 3.17 days in girls. 5) Utilization of medical facilities: The drug-store was consulted 91.2% of the total utilized boys and girls. The strengthening of medical facilities and medical care activities in health subcenter is urgently required 6) Medical Expenses by period and sex: a) Average medical expenses per surveyed 1,031 children were 35.95 won, per patient were 298.04 won during last month. b) Average medical expenses per survey children (omitted 1st school year) were 80.56 won, per patient were 243.98 won and per treated patient were 318.87 won during last year. c) Medical expenses were higher in boys than in girls. 7) Rohrer index by sex, present illness and school year. a) Average Rohrer index was 129.8 in boys and 126.2 in girls. b) Average Rohrer index was increased for 1st school year to 2nd school year and thereafter falling down step by step by school year. c) Under 151-160 Rohrer index number of code III was the highest and above 151-160 Rohrer index of code XII was peaked.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.6
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• pp.1210-1230
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• 1997

In this paper, we suggest an architecture of DS/CDMA tranceiver composed of one pilot channel used as reference and multiple traffic channels. The pilot channel-an unmodulated PN code-is used as the reference signal for synchronization of PN code and data demondulation. The coherent demodulation architecture is also exploited for the reverse link as well as for the forward link. Here are the characteristics of the suggested DS/CDMA system. First, we suggest an interlaced quadrature spreading(IQS) method. In this method, the PN coe for I-phase 1st channel is used for Q-phase 2nd channels and the PN code for Q-phase 1st channel is used for I-phase 2nd channel, and so on-which is quite different from the eisting spreading schemes of DS/CDMA systems, such as IS-95 digital CDMA cellular or W-CDMA for PCS. By doing IQS spreading, we can drastically reduce the zero crossing rate of the RF signals. Second, we introduce an adaptive threshold setting for the synchronization of PN code, an initial acquistion method that uses a single PN code generator and reduces the acquistion time by a half compared the existing ones, and exploit the state machines to reduce the reacquistion time Third, various kinds of functions, such as automatic frequency control(AFC), automatic level control(ALC), bit-error-rate(BER) estimator, and spectral shaping for reducing the adjacent channel interference, are introduced to improve the system performance. Fourth, we designed and implemented the DS/CDMA MODEM to be used for variable transmission rate applications-from 16Kbps to 1.024Mbps. We developed and confirmed the DS/CDMA MODEM architecture through mathematical analysis and various kind of simulations. The ASIC design was done using VHDL coding and synthesis. To cope with several different kinds of applications, we developed transmitter and receiver ASICs separately. While a single transmitter or receiver ASC contains three channels (one for the pilot and the others for the traffic channels), by combining several transmitter ASICs, we can expand the number of channels up to 64. The ASICs are now under use for implementing a line-of-sight (LOS) radio equipment.

• Journal of computational fluids engineering
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• v.13 no.4
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• pp.72-79
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• 2008

This study is to investigate the air flow around a sirocco fan which is used in a range hood. The main object of the study is to improve the flow rate of the fan by analysis of unsteady 3-dimensional incompressible flow. Overall analysis is carried out using CFD method. For this, we used a commercial code, SC/Tetra, and used a sliding mesh method to give the same condition as an actual state. First, verification of the CFD results is done by comparing the experimental data with the numerical data for the suction flow rate. It is confirmed that two results are well consistent. Then for the improvent of flow rate, the effect of shape factors such as diameter ratio of fan, geometry of case, cut-off aperture and guide angle of case exit on the suction flow rate was considered. Especially, for a new design of housing, the principle of Archimedes spiral was used. The overall analysis was applied to a new design of housing, and the result showed an increase of flow rate by 10.7%.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3529-3533
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• 2007

The advantages of the SITVC(secondary injection thrust vector control) technique over mechanical thrust vector systems include a reduction in both the nozzle weight and complexity due to the elimination of the mechanical actuators that are used in conventional vectoring. Computational study is performed to understand the fluidic thrust vectoring control of an axisymmetric nozzle, in which secondary gas injection is made in the divergent section of the nozzle. The nozzle has a design mach number 3. The effect of injection hole number and shape of secondary jet on the mach number distribution of SITVC were investigated. The standard ${\kappa}$ - ${\epsilon}$ turbulence model solved the complex three-dimensional nozzle flows perturbed by the secondary gas jet. The numerical code was validated by experiment. The results showed that the mach number distribution of circular and square nozzle are similar each other. As number of second injection hole increasing, a effect of deflection was decreased.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2839-2844
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• 2007

Micro hydraulic power generation of which the output is less or equal to a 100kW is attracting considerable attention. This is because of its small, simple, renewable, and abundant energy resources. By using a small hydropower generator of which main concept is based on using the different water pressure levels in pipe lines, energy which was initially wasted by use of a reducing valve at the end of the pipeline, is collected by turbine in the hydropower generator. A propeller shaped hydroturbine has been used in order to use this renewable pressure energy. In this study, in order to acquire basic design data of tubular type hydraulic turbine, output power, head, efficiency characteristics due to the flow coefficient are examined in detail. Moreover influences of pressure and velocity distributions with the variations of runner vane angle on turbine performance are investigated by using a commercial CFD code.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.494-496
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• 2002

A bi-directional and multi-channel wireless telemetry capsule, 11mm in diameter, is presented that can transmit video images from inside the human body and receive a control signal from an external control unit. The proposed telemetry capsule includes transmitting and receiving antennas, a demodulator, decoder, four LEDs, and CMOS image sensor, along with their driving circuits. The receiver demodulates the received signal radiated from the external control unit. Next, the decoder receives the stream of control signals and interprets five of the binary digits as an address code. Thereafter, the remaining signal is interpreted as four bits of binary data. Consequently, the proposed telemetry module can demodulate external signals so as to control the behavior of the camera and four LEDs during the transmission of video images. The proposed telemetry capsule can simultaneously transmit a video signal and receive a control signal determining the behavior of the capsule itself. As a result, the total power consumption of the telemetry capsule can be reduced by turning off the camera power during dead time and separately controlling the LEDs for proper illumination of the intestine.