• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.145-150
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• 2007

The spacer grid set is a component in the nuclear fuel assembly. The set supports the fuel rods saftely. Therefore, the spacer gl1d set should have sufficient strength for the external impact forces. The fretting wear occurs between the spring of the fuel rod and the spacer grid due to tile flow-induced vibration. The conceptual design of the spacer grid set is performed based on the Independence Axiom of axiomatic design. Two functional requirements are defined and corresponding design parameters are selected. The overall flow of the design is defined according to the application of axiomatic design. The design for the impact load is carried out by using nonlinear dynamic analysis to determine the length of the dimple. Topology optimization is carried out to determine a new configuration of the spring. The fretting wear is reduced by shape optimization using the homology theory. In the design to reduce the fretting wear, the deformed shape of the spring should be the same as that of the fuel rod. This condition is transformed to a function and considered as a constraint in the shape optimization process. The fretting wear is expected to be reduced due to the homology constraint. The objective function is minimizing the maximum stress to allow a slight plastic deformation. Shape optimization results are confirmed through nonlinear static analysis because the contact area becomes wider.

• Solar Energy
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• v.15 no.3
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• pp.29-38
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• 1995

The heat-storage characteristics accompanied by exothermic reaction at the regeneration of $Ca(OH)_2$ in tile heat-storage mode of a chemical heat pump system using a $Ca(OH)_2/CaO$ reversible thermochemical reaction was examined in a lab-scale unit. In this heat-storage mode, the particle bed of CaO could be regenerated by heating the $Ca(OH)_2$ packed bed to the higher temperature at which the equilibrium pressure in the reactor is greater than the water vapor pressure in the condenser. The results are i) the dehydration, thermal decomposition, rate of $Ca(OH)_2$ was higher at the lower part of particle bed than at the upper part, ii) in the reactor, the dehydration was proceeded along radial and axial direction, from inner part to the outer part, which explains heat transfers from the center to wall and from the tenter to lower or upper part of reactor.

• Journal of the East Asian Society of Dietary Life
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• v.27 no.4
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• pp.459-472
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• 2017

This study provides preliminary data to help organize improvements in analyzing the importance and performance of sanitation management items and the management of foodservice facilities in Community Child Centers in Daegu and Gyeongbuk Area. Questionnaires were distributed to 173 participants in sanitation and safety education at the center from April~June 2013 and 121 questionnaires were used as analysis data to investigate the management of foodservice facility at Community Children Centers in Daegu Gyeongbuk area. Most of the Community Child Centers are privately owned, and 62.0% had 20 to 29 children. Only 6.6% and 50.4% of the centers had nutritionists or cooks, respectively, due to budget deficits, and the foodservices were run by employees holding other positions. An investigation of sanitation management found that 84.3% of employees had a regular health inspection with significant differences between Daegu and Gyeongbuk (p<0.05). Most of the sanitation education was necessary, and the contents of sanitation education were applied to the fields in 66.1% of facilities. The reasons why the contents of them were not used in the fields included, the shortage of facilities and devices at 20.7%, which was the most common explanation. The separation separated of contaminated and non-contaminated areas were observed in 45.5% of facilities (p<0.01), separated sinks for pre-processing and cooking were found in 50.4%, and a show significant higher rate was noted in Daegu than in Gyeongbuk (p<0.05). An interior wall and, floor tile installation were observed 43.8% of facilities and a significantly higher rate was noted in Daegu than in Gyeongbuk (p<0.05). 30.9% of centers in Daegu and 11.3% of centers in Gyeongbuk area were equipped with a hot holding table(p<0.05). Overall, there is a need for education of foodservice to managers because most facilities do not have dietitians. In addition, facilities and equipment should be supplied continuously to foodservice facilities in community child centers.

• The Journal of Korean Academy of Prosthodontics
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• v.24 no.1
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• pp.165-176
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• 1986

The purpose of this study was to investigate electromyographically the relationship between preferred chewing side and side of initial muscle pains. In this study, 20 normal healthy subjects were selected , and each subject chewed randomly chewing gum for 20 minutes to establish preferred chewing side. To induce initial muscle pains, biting force of 10Kg on the gnathodynamometer was maintained by the subjects. And the Bioelectric processor EM2(Myo-Ironies Research, Inc. U.S.A.) with the surface electrodes was used to record the EMG activity during all experimental procedures. The results were as follows; 1. A majority of the present subjects (60%) had a preferred chewing side, but with few exceptions, subjects were unable to explain why a given side was preferred; explanations were only 'comfort' and 'habit' 2. The chewing, or working side was determined largely by the mean voltage of the surface electromyogram (EMG); in comparison with EMG from the non-wlring (contralateral) side, the working (ipsilateral) side showed a higher amplitude. 3. After the effort, the right masseter muscle is the most frequent site of pains, followed by the left masseter muscle, the anterior part of the right temporalis muscle and tile anterior part of the left temporalis muscle. 4. After the effort, mean voltages of masseter muscles were slightly increased, but mean voltages of temporalis anterior were slightly decreased at physiologic rest position. 5. No relationships could be established between preferred chewing side and side of initial muscle pains.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.302-305
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• 2003

3GPP RLC protocol specification adopted an error control scheme based on selective repeat ARQ. In the 3GPP ARQ, distinctive windows are provided at transmitting and receiving stations so that those stations are prohibited to send or receive data PDU's out of window. An increase in window size enhances delay performance. Such an increase, however, raises the occupancy at re-ordering buffer, which results in a long re-ordering time. Aiming at suppressing the occupancy at re-ordering buffer, we propose partial go back N scheme in this paper In the partial go back N scheme, the receiving station regards all data PDU's between the first (lowest sequence numbered) error-detected PDU and last (highest sequence numbered) error-detected PDU. By the employment of the partial go back N scheme, the occupancy at the re-ordering buffer is apparently reduced, while the delay and throughput performance may be degraded due to the remaining properties of go back N. We thus consider peak occupancy of re-ordering buffer, mean sojourn time at re-ordering buffer, mean delay time, and maximum throughput as measures to evaluate tile proposed scheme and investigate such performance by using a simulation method. From numerical examples, we observe a trade-off among performance measures and conclude that the partial go back N scheme is able to effectively reduce the occupancy of re-ordering buffer.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.4
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• pp.36-58
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• 1999

We designed the model picture of Tourism Botanical Garden, as a kind of theme park, in which we could enjoy flowers all the year round and the glorious tints of its autumn foliage. It would be very important to decide what kinds of trees should be planted and where to plant them. We selected the appropriate flowers and trees according to their value of appreciation and flowering time and the grand view around there and the weather conditions of the central region. We selected perennial plants as native plants, according to their color, flowering time and for the convenience of maintenance. And we selected some kinds of culture plants to show the seasonal change and diversity, according to their color and flowering time. We adopted the roof-tile pattern of Pakjae Kingdom to design the basic model of the garden, and the area was divided into eight sections. Six of them were divided again into four small planting areas from the outside respectively, according to the kinds of trees; pine-tree area, native flowering plant area, flowering tree area and flowering shrub area. The last two sections are by a lake, so they could make a beautiful landscape of waterfront. For the effective and economic operation of the garden, some kinds of flower trees and shrubs, which are little damaged by blight and are needless to prune, were selected. And perennial plants were also selected, because we don't have to change them into other plants, so we could cut down the expenses. As for the culture plants, they could be easily replaced with other culture plants in the flowering time, to show seasonal change and the harmony with the scenery around the garden.

• Convergence Security Journal
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• v.11 no.3
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• pp.31-37
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• 2011

Recently on tile network to ensure the anonymity of Mixed networking has been actively researched. It uses encrypted communications between Nodes and communications path is changed often to the attacker traceback and response, including the difficult thing is the reality. National institutions and infrastructure in these circumstances, the attack on the national level, if done on a large scale can be disastrous in. However, an anonymous network technology to cover up their own internet communication, it malicious form of Internet use by people who enjoy being continually updated and new forms of technology being developed is a situation continuously. In addition, attacks in the future application of these technologies is expected to continue to emerge. However, this reality does not deserve this thesis is prepared. In this paper, anonymously using a network to respond effectively to a cyber attack on the early detection research is to proceed.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.182-185
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• 2004

In this work, the effect of chemical treatments on surface properties of SiC was investigated in mechanical interfacial properties of carbon fibers-reinforced composites. The surface properties of the SiC were determined by acid/base values and contact angles. The thermal stabilities of carbon fibers-reinforced composites were investigated by thermogravimetric analysis (TGA). Also, the mechanical interfacial properties of the composites were studied in interlaminar shear strength (ILSS) and critical strain energy release rate mode II $(G_{IIC})$ measurements. As a result, tile acidically treated SiC (A-SiC) had higher acid value than that of untreated SiC (V-SiC) or basically treated SiC (B-SiC). According to the contact angle measurements, it was observed that chemical treatments led to an increase of surface free energy of the SiC surfaces, mainly due to the increase of the specific (polar) component. The mechanical interfacial properties of the composites, including ILSS and $(G_{IIC})$, had been improved in the specimens treated by chemical solutions. These results were explained that good wetting played an important role in improving the degree of adhesion at interfaces between SiC and epoxy resin matrix.

• Journal of ILASS-Korea
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• v.10 no.2
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• pp.1-9
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• 2005

An experimental study was carried out to obtain the fundamental data about the effects of radical ignition on premixture combustion. A CVC(constant volume combustor) divided into the sub-chamber and the main chamber was used. Numerous narrow passage holes are arranged between the main chamber and the sub-chamber. The products including radicals generated by spark ignition in tile sub-chamber derives the simultaneous multi-point ignition in the main chamber. We have examined the effects of the sub-chamber volume, the diameter and number of passage holes, and the equivalence $ratio({\Phi})$ on the combustion characteristics by means of burning pressure measurement and flame visualization. In a CVC, the overall burning time including the ignition delay became very short and the maximum burning pressure was slightly increased by the radical ignition(RI) method in comparison with those by the conventional spark ignition(SI) method. Combustible lean limit by RI method is extended by ${\Phi}=0.25$ compared with that by SI method. Also, In cases of charging the number and the diameter for the fixed total cross section of the passage holes, combustion period increased significantly at a sub-chamber with a single hole, but those of the other conditions had almost a similar tendency in the sub-chamber with 4 or more holes. regardless of equivalence ratio. Therefore, it was Proved that a critical cross section exists with the number of passage holes.

• Journal of Korean Association for Spatial Structures
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• v.7 no.1 s.23
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• pp.71-78
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• 2007

Stainless steel is very famous for using of industrials structure and joint elements. Stainless steel wire drawing is one of the most ancient crafts. But there's not any standard size of tapered die during tile drawing. This paper was studied die angle and dimension of whole die by using AFDEX drawing simulator. Stress, metal flow and strain rate was analyzed by AFDEX tools during the wire drawing. So optimum data of during dies was taken from them. Simulation data was correspond with experimental data. The results of the optimum dies are shown that (1) Reduction angle is $13.8^{\circ}$ (2) Bark relief angle is $20^{\circ}$ (3) Bearing length is 0.7975mm (4) Bearing dia is 0.2393mm The research of the optimum result when the make dies is connected an enterprise. After researching, I hope that indirection effect creation make development situation of the manufactural technical, practical application of the other die size by the detail data, utility factor and economical efficiency.