• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.10C
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• pp.1017-1026
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• 2005

In burst OFDM system, the frame synchronization should be performed first for the acquisition of received frame and the estimation of the correct FFT-window position. The conventional frame synchronization algorithms using design features of the preamble symbol, the repetition pattern of the OFDM symbol by pilot sub-carrier allocation rule and Cyclic Prefix(CP), has difficulty in the detection of precise frame timing because its correlation characteristics would increase and decrease gradually. Also, the algorithm based on the correlation between the reference signal and the received signal has performance degradation due to frequency offset. Therefore, we adopt a differential correlation method that is robust to frequency offset and has the clear peak value at the correct frame timing for frame synchronization. However, performance improvement is essential for differential correlation methods, since it usually shows multiple peak values due to the repetition pattern. In this paper, we propose an enhanced frame synchronization algorithm based on the differential correlation method that shows a clear single peak value by using differential correlation between samples of identical repeating pattern. We also introduce a normalization scheme which normalizes the result of differential correlation with signal power to reduce the frame timing error in the high speed mobile channel environments.

• Korean Journal of Applied Biomechanics
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• v.16 no.1
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• pp.31-41
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• 2006

The primary purpose of a TKA is to restore normal knee function Therefore, ideally, a TKA should: (a) maintain the natural leverage of the knee joint muscles to ensure generating adequate knee muscle moments to accomplish daily tasks such as rising from climbing stairs; (b) provide adequate knee joint stability. A 16-channel MyoResearch XP EMG system was used to collect the differential input surface electromyography signals VM, VL, RF, BF, ST during climbing/descending stair tests. A Peak Motion Measurement System was used to collect the kinematic and kinetic data. AKIN-COM Ill isokinetic dynamometer was used for EMG of VM, VL, RF, BF and ST during maximal voluntary contraction. I Quadriceps EMG results for the VM of the passed 1year group limb demonstrated significant less RMS EMG than that of the passed 3year group limb $60^{\circ}-15^{\circ}$ of knee flexion(p<0.05). The VL of the passed 1year group limb also demonstrated significants less RMS EMG than that of the passed 3year group limb from $60^{\circ}-45^{\circ}$ of knee flexion(p<0.05). Similar to the VM and VL, the RF of the passed 1year group limb showed less RMS EMG than that of the passed 3year group limb from $60^{\circ}-30^{\circ}$ do knee flexion(p<0.05). Hamstring EMG results for the BF of the passed 1year group limb demonstrated less RMS EMG than that of the passed 3year group limb from $75^{\circ}-15^{\circ}$ of knee flexion(p<0.05). The passed 1year group limb tended to have less ADD displacement(p<0.071) than that of the passed 3year group limb. There was no significant difference of the ABD displacement between the passed 1year group and the passed 3year group limbs(p<0.73). The passed 3year group used compensatory adaptation movement strategies to compensate for the strength deficit of passed 3year group limbs. The passed 3year group limb also increased the quadriceps muscle activation level to produce more knee extension moment to compensate for the short quadriceps moment arm. The passe 3year group limb might have an unstable knee joint in the medio-Iateral direction during the climbing/descending by showing a tendency of more ADD displacement and greater hamming co-activation EMG than the passed 1year group limbs. The TKA design was not able to help the knee joint to produce adequate knee extension moment with less quadriceps muscle effort. I think that old man needs continuous exercise for muscle strength.

• Journal of Astronomy and Space Sciences
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• v.26 no.1
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• pp.99-110
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• 2009

The main purpose of the current research is to developments a real-time Hardware In-the-Loop (HIL) simulation testbed for the satellite formation flying navigation and orbit control. The HIL simulation testbed is integrated for demonstrations and evaluations of navigation and orbit control algorithms. The HIL simulation testbed is composed of Environment computer, GPS simulator, Flight computer and Visualization computer system. GPS measurements are generated by a SPIRENT GSS6560 multi-channel RF simulator to produce pseudorange, carrier phase measurements. The measurement date are transferred to Satrec Intiative space borne GPS receiver and exchanged by the flight computer system and subsequently processed in a navigation filter to generate relative or absolute state estimates. These results are fed into control algorithm to generate orbit controls required to maintain the formation. These maneuvers are informed to environment computer system to build a close simulation loop. In this paper, the overall design of the HIL simulation testbed for the satellite formation flying navigation and control is presented. Each component of the testbed is then described. Finally, a LEO formation navigation and control simulation is demonstrated by using virtual scenario.

• Journal of Distribution Science
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• v.13 no.12
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• pp.65-71
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• 2015

Purpose - Domestic cooperatives tend to increase during the establishment of cooperatives and gradually through the basic law of social needs. However, only cooperatives' qualitative grow this secured without blessings, and their quantitative growth through government support is questionable. The purpose of this study is to analyze the agricultural cooperatives established through the Distribution System Cooperatives Basic Law, which was enacted in January 2012. Subsequently, establishing agricultural cooperatives was done briskly. However, cooperatives established rapidly after the founding of the Basic Law encountered problems. Research design, data, and methodology - To assess the performance of selected agricultural cooperatives, data were analyzed using the methodological Analytic Hierarchy Process (AHP) approach. The AHP is a set of systematic procedures to hierarchically analyze the elements of any problem. Using a survey on expertise, a series of comparative determinations of each pair is performed to evaluate the relative strengths and the strengths of the impact between elements within the hierarchy. A survey was conducted on 10 small agricultural cooperatives using AHP analysis for the examination. The purpose of such research and analysis is to recommend a direction for future policies aimed at small agricultural cooperatives. Result - This study applied three types of policy evaluation criterion, including market expansions, organizations, and cooperative projects, and 12 types of small agricultural cooperative policy measures. Market expansion policies for agricultural cooperatives are classified into four categories: school meals, direct transactions, shopping malls, and wholesale markets. Organizational policies for agricultural cooperatives are classified into four types: existing sales channel management, education, preventing free riding, and enlarging members. Cooperative project policies in agricultural cooperatives are classified into four policy areas: cooperation between cooperatives, community contribution, joint businesses, and government links. In this paper, the growth priority in agricultural cooperative policies is analyzed by applying policy evaluation criteria on the basis of a survey on expertise. The priorities of the policy program are also analyzed using a decision analytic hierarchy process. The results indicate that market expansion is the most important policy evaluation criterion therefore, improving direct transactions, school meals, management of existing sales channels, and shopping malls are crucial policy measures. In contrast, the cooperation of cooperatives, expansion of union members, and cooperation with the government were found to have low priority. Conclusions - Agricultural cooperatives should develop plans as follows. Small agricultural cooperatives need to secure school meals and direct transactions for market expansion, restructure marketing strategies to manage existing sales channels, and, finally, increase education and training for sustainable organizational development. This study has the following limitations. Because the subject of the investigation is a new cooperative, determining its sustainable growth is difficult. Therefore, through analysis and a continuous study of cooperatives, future research is expected to show that modifying the direction of agriculture cooperatives is necessary.

• Journal of Distribution Science
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• v.12 no.6
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• pp.5-13
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• 2014

Purpose - The purposes of this editorial review are twofold: firstly, to introduce the four flagship international journals of the Korea Distribution Science Association(KODISA): the Journal of Distribution Science(JDS), the Journal of Industrial Distribution & Business(JIDB), the East Asian Journal of Business Management(EAJBM), and the Journal of Asian Finance, Economics and Business(JAFEB), and secondly, to identify the direction of the KODISA journals and the roles and responsibilities of the editors of the KODISA journals. Research design, data, and methodology - To achieve the goals, firstly, this review paper addresses the current progress of the four KODISA journals: JDS, JIDB, EAJBM, and JAFEB. Secondly, this paper defines the aims and missions of the four KODISA journals. JDS publishes the articles of examining past, current, and emerging trends and concerns in the area of distribution science and economics, logistics and SCM, transportation, distribution channel management, distribution innovation and information technology, merchandising and procurement, distribution and marketing, consumer behavior, and manufacturing, wholesaling, and retailing. JDS publishes both quantitative and qualitative research as well as scholarly commentaries, case studies, book reviews and other types of reports relating to all aspects of distribution. JIDB publishes the articles of examining past, current, and emerging trends and concerns in the areas of industry and corporate behavior, industry policy making, industrial distribution and business, e-commerce, and service industry. EAJBM publishes empirical and theoretical research papers as well as scholarly commentaries, case studies, book reviews, and other types of reports relating to all aspects of East Asian business and economy. JAFEB publishes original research analysis and inquiry into the contemporary issues of finance, economics and business management in Asia, including Central Asia, East Asia, South Asia, Southeast Asia, and Middle East. The mission of JAFEB is to bring together the latest theoretical and empirical finance, economics and business management research in Asian markets. The audiences of the KODISA journals include higher education institutions, scholars, industry researchers and practitioners, scientists, economists, and policy makers throughout the world. The main mission of the KODISA journals is to provide an intellectual platform for international scholars, promote interdisciplinary studies in social sciences and economics, and become leading journals in the social science and economics category in the world. Thirdly, this paper addresses the current status of indexing in major databases of the KODISA journals, namely: Cabell's Directories, EBSCO, SCOPUS (Elsevier), and Social Sciences Citation Index^® (SSCI, Thomson Reuters). Fourthly, this paper identifies the roles and responsibilities of the editors of the KODISA journals as the following: (1) Make sure that the journal be published in a timely manner and in international standards both in print and online versions. (2) Maintain the online homepage of the journal is always accessible to, and (3) Make sure that every article should go through a peer review process that meets international standards. Findings and conclusion - To accomplish the goals and missions of the KODISA journals, the editors of the KODISA journals must work together to publish high scholarly journals that meet international standards of journal publications.

• Journal of Distribution Science
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• v.16 no.8
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• pp.79-89
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• 2018

Purpose - This research aims to investigate the factors that influence consumer's overseas online shopping behavior. Consumers adopt overseas online shopping as a new buying way and more and more consumers prefer overseas online shopping than traditional shopping ways. Consumers' behaviors in this shopping experience can be different from other shopping experiences. With the increase of overseas online shopping, we need to find antecedents and results of overseas online shopping. Especially there would be positive or negative factors which influence overseas online shopping motivation. To find the relationship, this study examines self-efficacy and impulsivity as major factors which influence overseas online shopping. We also suggest that several attitude factors increase self-efficacy and it is positively related to customer satisfaction. On the other hand, we assume that overseas online shopping factors influence impulsivity of buying and it will decrease customer satisfaction. Research design, data, and methodology - This empirical study data were collected from Korean people who experience overseas online shopping. The subjects for this study were confined to shoppers who used overseas online shopping within the past six months. A total of 267 responses were gathered. SPSS 23.0, PLS 2.0 software were used in the data analysis. Descriptive statistics were used to show sample characteristics. We examined reliability, validity test for constructs. All measurement items used seven-point scales(1= very strong disagree, 7 = very strongly agree) drawn from previously published papers. Partial Least Square method was applied to find the relationship between antecedent factors and dependent factors and hypotheses were estimated. Results - Results show that perceived superiority, perceived ease of use, perceived transaction safety, perceived behavioral control positively affect self-efficacy. Self-efficacy influences positively to consumer's post purchase satisfaction. Perceived monetary benefit and perceived uniqueness motivated impulse buying. This can make consumer's post purchase dissatisfaction. Conclusions - This paper attempted to confirm the existence of both the positive and negative faces of overseas online shopping. The result reveals that self-efficacy is a major factor which may increase satisfaction in the overseas online shopping. Usually, we can think monetary benefit and uniqueness of products motivate overseas online shopping. But it can also intrigue impulse buying and negatively affect customer relationship. Therefore companies should provide enough products information to their potential customers and they might apply adequate processes such as recommendation, comparing systems to build long term relationship with their customers.

• Journal of the Korea Society for Simulation
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• v.20 no.1
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• pp.79-85
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• 2011

The problem of evacuating pedestrians from a room or channel under panic conditions is of obvious importance in daily life. In recent years, several computer models have been developed to simulate pedestrian dynamics. Understanding evacuation dynamics can allow for the design of more comfortable and safe pedestrian facilities. However, these models do not take into account the type and state of mind of pedestrians. They deal with pedestrians as particles and the state of mind as a social force, which is represented by conservative and long-range interactions between individuals. In this study, I used the lattice model proposed in my previous study to explore the evacuation behavior of pedestrians with morality. In this model, three types of pedestrians are considered: adults, children, and injured people. Collisions between adults and children result in injured people. When the number of injured people continuously in contact with each other reaches a given value k, the injured people are removed from the lattice space. This situation is the same as that in which pedestrians start stepping over injured people. This behavior was interpreted as the morality of pedestrians. Simulations showed that the evacuation showed down and eventually became jammed owing to the injured people acting as "obstacles" in relation to the morality k.

• Journal of the Ergonomics Society of Korea
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• v.32 no.6
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• pp.517-528
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• 2013

Objective: The objective of this study was to suggest a multi-modal controller type for Smart TV Control. Background: Recently, many issues regarding the Smart TV are arising due to the rising complexity of features in a Smart TV. One of the specific issues involves what type of controller must be utilized in order to perform regulated tasks. This study examines the ongoing trend of the controller. Method: The selected participants had experiences with the Smart TV and were 20 to 30 years of age. A pre-survey determined the first independent variable of five tasks(Live TV, Record, Share, Web, App Store). The second independent variable was the type of controllers(Conventional, Mouse, Voice-Based Remote Controllers). The dependent variables were preference, task completion time, and error rate. The experiment consist a series of three experiments. The first experiment utilized a uni-modal Controller for tasks; the second experiment utilized a dual-modal Controller, while the third experiment utilized a triple-modal Controller. Results: The first experiment revealed that the uni-modal Controller (Conventional, Voice Controller) showed the best results for the Live TV task. The second experiment revealed that the dual-modal Controller(Conventional-Voice, Conventional-Mouse combinations) showed the best results for the Share, Web, App Store tasks. The third experiment revealed that the triple-modal Controller among all the level had not effective compared with dual-modal Controller. Conclusion: In order to control simple tasks in a smart TV, our results showed that a uni-modal Controller was more effective than a dual-modal controller. However, the control of complex tasks was better suited to the dual-modal Controller. User preference for a controller differs according the Smart TV functions. For instance, there was a high user preference for the uni-Controller for simple functions while high user preference appeared for Dual-Controllers when the task was complex. Additionally, in accordance with task characteristics, there was a high user preference for the Voice Controller for channel and volume adjustment. Furthermore, there was a high user preference for the Conventional Controller for menu selection. In situations where the user had to input text, the Voice Controller had the highest preference among users while the Mouse Type, Voice Controller had the highest user preference for performing a search or selecting items on the menu. Application: The results of this study may be utilized in the design of a controller which can effectively carry out the various tasks of the Smart TV.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.10
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• pp.144-155
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• 1998

The array weights that will maximize the SNR for any type of noise environment are determined by the function of the antenna design configuration and the directions of receiving target and interference signals. The conventional SLCs(sidelobe cancellers) using the SNR maximization perform worst from the saturation of the receiving system of main channel when the main antenna has pattern with high gain at the arrival angle of strong interference. In this paper, the new SLC is accomplished by using two independent antenna architecture. Main antenna is implemented with adaptive nulling, which is used for rejecting high-power interference primarily. Auxiliary antenna is realized with adaptive array for receiving interference signal to be suppressed completely, which has a characteristics of sufficient gain for every direction. The new SLC is implemented with above both antennas. We show that the new SLC, which consists of the adaptive nulling main antenna and the adaptive array auxiliary antenna, is useful in reducing the effect of strong interference like jammer, because the adaptive nulling at main antenna prevents its receiver and signal processor for saturation by strong interference. The proposed SLC has improved SNR over the conventional SLCs. The improved SNR at sidelobe region is typically more than 7 dB for a given test signal. Moreover, it improves the SNR of about 20 dB under strong interference at mainlobe.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.5
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• pp.103-111
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• 2007

In this paper, we propose a VLSI architecture of hardware optimized high quality image signal processor for a Single-chip CMOS Image Sensor(CIS). The Single-chip CIS is usually used for mobile applications, so it has to be implemented as small as possible while maintaining the image quality. Several image processing algorithms are used in ISP to improve captured image quality. Among the several image processing blocks, demosaicing and image filter are the core blocks in ISP. These blocks need line memories, but the number of line memories is limited in a low cost Single-chip CIS. In our design, high quality edge-adaptive and cross channel correlation considered demosaicing algorithm is adopted. To minimize the number of required line memories for image filter, we share the line memories using the characteristics of demosaicing algorithm which consider the cross correlation. Based on the proposed method, we can achieve both high quality and low hardware complexity with a small number of line memories. The proposed method was implemented and verified successfully using verilog HDL and FPGA. It was synthesized to gate-level circuits using 0.25um CMOS standard cell library. The total logic gate count is 37K, and seven and half line memories are used.