• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.5
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• pp.40-45
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• 2008

In this paper, a microstrip linear tapered slot antenna is designed. A tapered slot antenna(TSA) has many advantages such as low profile, low weight, easy fabrication, and compatibility with monolithic microwave integrated circuits(MMIC). In addition, it has demonstrated multi octave bandwidth, moderately high gain, and symmetrical E- and H-plane beam patterns. A feed network is implemented with transition between a microstrip and a slot line for the microstrip linear tapered slot antenna. The transition is consist of two sides. One side has a microstrip line, the other side has a slot line. The dimensions of the microstrip and slot line are ${\lambda}_m/4$ and ${\lambda}_s/4$ at the center of the cross section of the microstrip and slot line. In order to get broad bandwidth antenna characteristics, the tapered length is chosen as $4{\lambda}_o$ and termination width is chosen as $1.75{\lambda}_o$. Experimental results show that the microstrip tapered slot antenna has symmetrical E- and H-plane beam patterns with around 5GHz of bandwidth at center frequency of 5.0GHz.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.437-445
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• 2015

The layout of facilities, in relation to information and navigational displays, has great influence on subway satisfaction, and tend to vary depending on the types of subway platform and transit station. However, until now, few studies have covered such aspects as of yet. Starting from this viewpoint, the purpose of this study was to use an IPA analysis technique to analyze that satisfaction on the importance of facilities to aid in accessibility, such as elevators and escalators, transit amenities and information and navigational displays depending on the types of platform and transit station. To do so, we've classified 15 metropolitan stations according to types of platform and transit station and analyzed differences in user importance and satisfaction as well as improvements for platforms and transit stations of similar type. By the analysis results of this study, we've concluded that the proper selection and positioning of elevator and escalator facilities and information and navigational displays was important when designing the subway station according to platform type (separate platform) and or according to the transit station type (cross, L, T types) where pedestrian flow heavily intersected. We considered that such analysis results would be helpful in the design of new stations and the enhancement of existing stations pursuant to a new direction that minimizes user inconvenience, and that improvement items should be developed first according to the platform and transit station types, which would be helpful in enhancing the efficiency of the subway improvement cost.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.12
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• pp.1223-1231
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• 2010

The design is presented for a SATCOM antenna capable of simultaneous multi-band (X/Ku/Ka-Band) communications without replacement of feed horns or change of other parts in the application as a ground satellite terminal for large data transfer. The antenna is the offset configuration and consists of a dual-band(X/Ka-band) feed horn, a single-band(Ku-band) feed horn, a frequency selective surface(FSS) sub-reflector and a parabolic main-reflector. The antenna has a main reflector defining a prime focus and a frequency selective surface sub-reflector defining an image focus. A dual-band feed and a single-band feed are provided at each of the prime focus and image focus. The antenna is designed using 3D EM simulator and the gains measured in X/Ku/Ka-band of the complete antenna assembly is more than 31.6dBi, 36.8dBi, 40.8dBi, and the cross polarization is 21.7dB, 26.6dB, 25.2dB, respectively.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.10
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• pp.397-406
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• 2014

In order to answer the questions successfully on behalf of the human in DeepQA environments such as Jeopardy! of the American quiz show, the computer is required to have the capability of fast temporal and spatial reasoning on a large-scale commonsense knowledge base. In this paper, we present a scalable spatial reasoning algorithm for deriving efficiently new directional and topological relations using the MapReduce framework, one of well-known parallel distributed computing environments. The proposed reasoning algorithm assumes as input a large-scale spatial knowledge base including CSD-9 directional relations and RCC-8 topological relations. To infer new directional and topological relations from the given spatial knowledge base, it performs the cross-consistency checks as well as the path-consistency checks on the knowledge base. To maximize the parallelism of reasoning computations according to the principle of the MapReduce framework, we design the algorithm to partition effectively the large knowledge base into smaller ones and distribute them over multiple computing nodes at the map phase. And then, at the reduce phase, the algorithm infers the new knowledge from distributed spatial knowledge bases. Through experiments performed on the sample knowledge base with the MapReduce-based implementation of our algorithm, we proved the high performance of our large-scale spatial reasoner.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.2
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• pp.98-106
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• 2011

The deck of steel box girder bridges is composed of deck plate, longitudinal rib, and transverse ribs. The orthotropic steel decks have high possibility to fatigue damage due to numbers of welded connection part, the heavy contact loadings, and the increase of repeated loadings. Generally, the local stress by the repeated loadings of heavy vehicles causes the orthotropic steel deck bridge to fatigue cracks. The increase of traffic volume and heavy vehicle loadings are promoted the possibility of fatigue cracks. Thus, it is important to exactly evaluate the structural behavior of bridge considering the contact loading area of heavy vehicles and real load patterns of heavy trucks which have effects on the bridge. This study estimated the effect of contact area of design loads and real traffic vehicles through the finite element analysis considering the real loading conditions. The finite element analysis carried out 4 cases of loading patterns in the orthotropic steel deck bridge. Also, analysis estimated the influence of contact area of real truck loadings by the existence of diaphragm plate. The result of finite element analysis indicated that single tire loadings of real trucks occurred higher local stress than one of design loadings, and especially the deck plate got the most influence by the single tire loading. It was found that the diaphragm attachment at joint part of longitudinal ribs and transverse ribs had no effects on the improvement of structural performance against fatigue resistance in elastic analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1393-1401
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• 2013

What is RFID Microchip tag attached to an object, the reader recognizes technology collectively, through communication with the server to authenticate the object. A variety of RFID tags, 13.56Mhz bandwidth RFID card, ISO/IEC 14443 standards based on NXP's Mifare tag occupies 72.5% of the world market. Of the Mifare tags, low cost tag Mifare Classic tag provided in accordance with the limited hardware-based security operations, protocol leaked by a variety of attacks and key recovery vulnerability exists. Therefore, in this paper, Cryptography Scheme and Secure Protocol for Safety Secure Scheme Construction in 13.56Mhz RFID have been designed. The proposed security scheme that KS generated by various fixed values and non-fixed value, S-Box operated, values crossed between LFSR and S-Box is fully satisfied spoofing, replay attacks, such as vulnerability of existing security and general RFID secure requirement. Also, It is designed by considering the limited hardware computational capabilities and existing security schemes, so it could be suit to Mifare Classic now.

• Korean Journal of Occupational Therapy
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• v.26 no.4
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• pp.43-55
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• 2018

Objective : The purpose of this study was to investigate the effects of fidget spinner training on the hand function and handwriting legibility of lower grade elementary school studens. Methods : This study randomly assigned a study group of 12 children and control group of 12 children from 24 children in grade 1 and 2 (ages 7 through 8), whose are dominantly right handed. The study used was a pre-post process. The intervention was conducted only on the study group twice a week for 5 weeks and for 40 minutes per session, for a total of ten sessions. The measuring instruments used to compare the hand functions and handwriting legibility were the Jebsen-Taylor Hand Function Test, Grip Strength Test, and Legibility Test. The data analysis used a Wilcoxon signed rank, Mann-Whitney U and Chi-Square cross analysis. Results : The fidget spinner training showed significant improvement in the study group's hand function(grip strength and handwriting legibility) and a significant difference was shown between the control and study groups. Conclusion : This study confirmed the value and utility of a fidget spinner as a tool for improving the hand function and handwriting legibility of elementary school students in lower grades. Future studies are expected to verify the effectiveness of the fidget spinner training based on the present study.

• Journal of the Korea Convergence Society
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• v.12 no.1
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• pp.211-218
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• 2021

This study is composed of a convergence research design plan as the necessity of information security field dealing with human factors are raised. The purpose of this study is to analyze the effectiveness of the aspect of information security on the cognitive process related to security policy. The research method consisted of the cross-design of the availability dimension and the culture dimension, and the information security process was measured with information security awareness, response efficacy, compliance behavioral intention, and information security behavior. As a result of the study, the dimension of availability had a significant effect on response efficacy, and it was found that the influence of the case-based condition was greater than that of the statistics-based condition. The cultural dimension had a significant effect on information security awareness, response efficacy, compliance behavioral intention, and information security behavior, and the influence of the homogeneity condition was found to be greater than that of the diversity condition. The proposed research model was verified as a multiple mediation model reconstructed with measurement variables. In addition, the discussion describes the necessity of an information security strategy in consideration of individual factors and organizational characteristics.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.1
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• pp.13-22
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• 2022

In this paper, we propose single and array antenna with dual linear polarization characteristics for 28 GHz band. The proposed antenna is designed two microstirp feeding structure and Taconic TLY-5 substrate, which is thickness 0.5 mm, and the dielectric constant is 2.2. The size of single patch antenna is 3.4 mm×3.4 mm, and total size of single antenna is 15.11 mm×15.11 mm. Also, the size of array antenna is 3.15 mm×3.15 mm, and total size of array antenna is 21.5 mm×13.97 mm. From the fabrication and measurement results, for 1×2 array antenna, in case of vertical polarization, cross polarization ratios are obtained from 14.23 dB to 20.79 dB and in case of horizontal polarization, cross polarization ratios are obtained from 14.31 dB to 22.74 dB for input port 1. in case of vertical polarization, cross polarization ratios are obtained from 15.75 dB to 25.88 dB and in case of horizontal polarization, cross polarization ratios are obtained from 14.70 dB to 22.82 dB for input port 2.

• Progress in Medical Physics
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• v.20 no.3
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• pp.139-144
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• 2009

Recently, the mathematical analysis of stent simulation has been improved, with the help of development of various tool which measure mechanical property and location of stent in artery. The most crucial part of the stent modeling is how to design ideal stent and to evaluate the interaction between stent and artery. While there has been great deal of researches on the evaluation of the expansion, stress distribution, deformation of the stent in terms of the various parameters, few verification through computer simulation has been performed about deformation and stress distribution of the stent. In this study, we have produced the corresponding results between experimental test using Universal Testing Machine and computer simulation for the ideal model of stent. Also, we have analyzed and compared stress distribution of stent in the cases of that with membrane and that without membrane. The results of this study would provide minimum change of plan and good quality for ideal stent replacing damaged artery through the analysis using computer simulation in the early stage of stent design.