• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.914-925
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• 1998

This paper considers the evaluation of the hybrid acquistion perdformance for the pilot signal in the direct sequence code division multiple access(DS/CDMA) forward link. the hybrid acquisition is introduced by the combination of two schemes, the parallel and serial acquisions. The mean acquisition time of the proposed scheme is derived to consider both the best case(the correct code-phase offsets are included i one subset) and the worst case(the correct code-phase offsets exist at the boundary of two subsets), which are cause by the distribution of the correct code-phase offsets in the subset. Expressions for the detection, false alarm, and miss probabilities are derived for the case of multiple correct code-phase offsets and multipath Rayleigh fading channel. Numerical results present the hybrid acquistion performance with repect to design parameters such as postdetectio integration length in the search and verification modes, subset size, and number of I/Q noncoherent correlators, and compare the hybrid acquistion with the parallel acquistion in terms of the minimum acquistion time under the same hardware complexity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10A
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• pp.1563-1570
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• 1999

This paper relates to the soft decision method with erasure technique in digital terrestrial television broadcasting system. The proposed decoder use the CSI derived from using the pilots in receiver. The active real(I) and imaginary(Q) data are transferred to the branch metric calculation block that decides the Euclidean distance for the soft decision decoding and also the estimated CSI values are transferred to the same block. After calculating the Euclidean distance for the soft decision decoding, the Euclidean distance of branch metric is multiplied by CSI. To do so, new branch metric values that consider each carrier state information are obtained. We simulated this method in better performance of about 0.15dB to 0.17dB and 2.2dB to 2.9dB in Rayleigh channel than that of the conventional soft decision Viterbi decoding with or without bit interleaver where the constellation is QPSK, 16-QAM and 64-QAM.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.10
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• pp.593-600
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• 2014

OFDMA systems solves frequency selective fading problem and provides improved performance by optimal allocation of subcarriers and transmit power. Two-way relay systems provide improved spectral efficiency compared to that of the conventional half-duplex relay using bidirectional communications. In legacy OFDMA system such as WiBro, two-way DF relay utilization causes pilot re-assignment and impossibility of channel estimation and decoding at relay nodes by self-interference. In this paper, resource allocation schemes for legacy OFDMA systems with two-way DF relay are proposed. The proposed schemes allocate subcarriers considering destinations nodes which are connected to relay nodes as individual nodes which are directly connected to a base station. Subsequently, the proposed schemes compensate bandwidth loss due to orthogonal allocations by overlapped allocating unused subcarriers at other noes. Numerical simulations show that the proposed resource allocation schemes provide improved performance compared with orthogonal allocation.

• Journal of Family Resource Management and Policy Review
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• v.19 no.4
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• pp.121-140
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• 2015

This study tried to develop and suggest the program for the family friendly culture in Healthy Families Center. This study focused on specially the cooking program on which entire family member can participate. To develop the program two theoretical perspectives were applied : 1. healthy families perspectives and family leisure, 2. child development perspectives. In the process for developing the program the related literatures were investigated and the proceding cases were analized. The developed program consisted of 4 parts : 1. today, I(child) am the chef, 2. today, daddy(or mommy) is the chef, 3. for my parents and for my kids, 4. let's take a familytrip with snacks. This program is to be made suitable for the families with child(ren) in school age. We suggested various strategies for the effective management the program in Healthy Families Center such as the program manual and workbook, the time duration of program, three steps(introduction-performance-closing) of each session and using the professionals. We suggested the pilot performance of this program for the confirmation the effectiveness of the program. The evaluation index can be used before and after the program implementation. Further research needs to investigate the program for another family life cycle, such as the family with the child(ren) of preschool age or youth child(ren). In addition, for the enhancement of professionals quality who lead the program in field the professionals academy or education program need to be offered.

• Journal of the Ergonomics Society of Korea
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• v.32 no.3
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• pp.217-227
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• 2013

Objective: The purpose of this study was to analyze 'response time', 'peak response time' and 'overshoot value' for each muscle by applying the EMG signal to the vehicle response in ISO 7401 and to quantify the response of the driver according to vehicle characteristics by comparing vehicle characteristics and muscle responses of the driver. Background: The Open-loop test defined in international standards ISO 7401 is the only method for evaluating the performance of the vehicle. However, this test was focused only on mechanical responses, not driver's ones. Method: One skilled male driver(22 yrs. experience) was participated in this experiment to measure muscle activities of the driver in transient state. Then the seven muscle signals were applied to calculate 'response time', 'peak response time', and 'overshoot value'. Results: In the analyses of the EMG data, the effects of vehicle type and muscle were statistically significant on the 'response time' and 'peak response time'. Also, the effects of vehicle type, muscle, and lateral acceleration level were statistically significant on the 'overshoot value' in this study. According to the analyses of the vehicle motion data, vehicle motion variable(LatAcc, Roll, YawVel) was statistically significant on the 'response time' and vehicle type, vehicle motion variable, and lateral acceleration level were statistically significant on the 'peak response time', respectively. Conclusion: In the analyses of the 'response time' and 'overshoot value', the data of muscle activities(EMGs) was better index that could evaluate the vehicle characteristic and performance than the data of vehicle motion. In case of peak response time, both EMG and vehicle motion data were good index. Application: The EMGs data from a driver might be applicable as index for evaluation of various vehicle performances based on this study.

• Journal of Digital Convergence
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• v.8 no.4
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• pp.185-204
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• 2010

This case study quantifies the savings that can be realized through integration in National Computing & Information Agency (NCIA) of the Korea Government. It is based on the process of the NCIA development project that consolidating and integrating distributed 24 agencies. And it used the widely accepted Gartner TCO (Total Cost of Ownership) Solution and applies that methodology consistently before and after integration. Specific measurement items for examining the information system integration saving cost are developed pilot test for 2 agencies through compare TCO before integration and TCO after integration. The results of measuring on information system integration in NCIA are showed lots of economic cost reduction in TCO by integrating and consolidating each computing environment in agency. Especially in detail, NCIA realized the most savings in IT Capital Cost including development of hardware, software and recovery system. Also IT Support Cost and IT Administration Cost examined more savings than before IT integration.

• Korean Journal of Construction Engineering and Management
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• v.7 no.4 s.32
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• pp.78-90
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• 2006

There is no specific code and/or standard described in the specifications to check verticality for Pre-tensioned Spun High Strength Concrete pile installation process. The most commonly used method for the vertical PHC pile installation is a naked-eye measurement or water level measurement conducted by assistant crew in the construction sites. The main objective of the research is to develop the automated vertical controllable prototype equipment for PHC piles in order to achieve uniform construction qualify as well as improving safety and productivity. The paper explains the literature review on PHC pile and pile installation process, development of prototype, field test of the prototype and its performance evaluation in terms of quality and safety as well as productivity. The results of the research will lead the further researches on the automated pile installation system.

• Korean Journal of Community Nutrition
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• v.17 no.1
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• pp.91-100
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• 2012

This study aimed to evaluate the effectiveness of the foodservice management support program focusing on menu management in community child centers. The support program provided reference menus, staff training, and field consulting to 10 community child centers in the Jeollanam-do province for one month, August in 2010. One month menus were developed, based on children's preference for menu items, foodservice personnel's preference for food materials, and availability of local specialty foods, and offered as reference menus. In addition, staff training and field consulting focusing on menu management were conducted before and during the pilot period, respectively. To evaluate the support program, menus, foodservice personnel's knowledge level and perceived performance in foodservice management, and children's level of satisfaction for foodservice were analyzed before and after the support program. As a result of analysis of 222 and 210 menus of before and after the support program, respectively, the number of dishes per meal increased from five to six on average, and the proportion of meals including five food groups, which were grain, meat, vegetable, fruit, and milk and dairy product, rose from 2% to 24%. Foodservice personnel's knowledge level regarding foodservice management increased significantly (p = 0.007), however, their perceived performance in foodservice management did not show any significant changes. Children were more satisfied with 'food' (p = 0.001), 'sanitation' (p = 0.001), and 'environment' (p < 0.008) of foodservice in community child centers after the support program. In conclusion, the foodservice management support program focusing on menu management in this study was effective for improving menu quality of and children's satisfaction with foodservice in community child centers.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.2
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• pp.393-400
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• 2015

As the development and distribution of the intelligent transport system is spreading recently and some of the services are commercialized through a pilot project, interest in DSRC with high utilization is increasing and antennas for roadside and on board equipment are being studied. A single patch was used for a vehicle antenna due to the requests of miniaturization of size, but there was performance degradation in most cases due to miniaturization. In addition, some methods to improve performance have been used in the antennas that were previously researched using the arrays, but they have the disadvantages of bulkiness in size of the antennas when using the arrays. Therefore, in this paper, the CPW fed microstrip patch antenna with the simple structure of being compact and easy to produce, which can be used in the OBU of DSRC, was designed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.3 s.246
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• pp.278-286
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• 2006

Experiments were conducted to estimate the performance of drag force type vertical axis wind turbine with an opening-shutting rotor. It was operated by the difference in drag force generated on both sides of the blades. The rotational speed was measured by a tachometer in a wind tunnel and the tunnel wind speed was measured by using a pilot-static tube and a micro manometer. The performance test for a prototype was accomplished by calculating power, power coefficient, torque coefficient from the measurement of torque and rpm by a dynamometer controller. Various design parameters, such as the number of blades(B), blade aspect ratio(W/R), angle of blades$(\alpha)$ and drag coefficient acting on a blade, were considered for optimal conditions. At the experiment of miniature model, maximum efficiency was found at N=15, $\alpha=60^{\circ}$ and W/R=0.32. The measured test variables were power, torque, rotational speed, and wind speeds. The data presented are in the form of power and torque coefficients as a function of tip-speed ratio V/U. Maximum power was found in case of $\Omega=0.33$, when the power and torque coefficient were 0.14 and 0.37 respectively. Comparing model test with prototype test, similarity law by advance ratio for vertical axis wind turbine was confirmed.