• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.9
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• pp.723-732
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• 2017

Simplified factorizing-technique to improve the efficiency on computational procedure and the complexity of the conventional back-projection algorithm, which is used to reconstruct airborne FMCW-SAR image, is suggested, and the reconstruction process of SAR image by this simplified factorizing-technique are presented in this paper. This technique can be efficiently applied to airborne FMCW-SAR having a relatively narrow beamwidth and long synthetic aperture length, and its basic rationale is to exclude the data that has low level of contribution during computational procedure. Using the raw data of practical airborne FMCW-SAR system, performances of this proposed technique such as SAR image quality and processing time were compared and analyzed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8B
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• pp.706-711
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• 2012

The current visible light communication (VLC) systems have a short transmission distance and a low data rate. To overcome this, we studied on the method of appling MIMO technology to VLC. However, it is difficult to apply the original MIMO technology used in RF frequency to wireless VLC. In VLC system, a lens can be used to separate the transmitted signals. And, if we use an image sensor as the receiver, MIMO technology can be applied to LED wireless visible light communication. In this paper, we report an experiment of $2{\times}2$ LED wireless visible light communication using a commercial image sensor receiver. We show the experimental demonstration with a transmission length of 10.5 m and a data rate of 200 bit/s.

• Wind and Structures
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• v.17 no.1
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• pp.43-68
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• 2013

The fluctuating wind induced vibration is one of the most important factors which has been taken into account in the design of long-span bridge due to the low stiffness and low natural frequency. Field measurement characteristics of sustained wind on structure site can provide accurate wind load parameters for wind field simulation and structural wind resistance design. As a suspension bridge with 1490 m main span, the Runyang Suspension Bridge (RSB) has high sensitivity to fluctuating wind. The simultaneous and continuously wind environment field measurement both in mid-span and on tower top is executed from 2005 up to now by the structural health monitoring system installed on this bridge. Based on the recorded data, the wind characteristic parameters, including mean wind speed, wind direction, the turbulence intensity, the gust factors, the turbulence integral length, power spectrum and spatial correlation, are analyzed in detail and the coherence functions of those parameters are evaluated using statistical method in this paper. The results indicate that, the turbulence component of sustain wind is larger than extremely strong winds although its mean wind speed is smaller; the correlation between turbulence parameters is obvious; the power spectrum is special and not accord with the Simiu spectrum and von Karman spectrum. Results obtained in this study can be used to evaluate the long term reliability of the Runyang Suspension Bridge and provide reference values for wind resistant design of other structures in this region.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.18-26
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• 2001

In this paper, the resonant characteristics and modes of the film bulk acoustic wave resonator (FBAR) used in 1~2 GHz frequency region are analyzed by it's input impedance which was calculated by three dimensional finite element method formulated as eigenvalue problem using electro-mechanical wave equation and boundary condition. It was extracted that the resonant and the spurious characteristics considering the effects of electrode area and shape variation and unsymmetry of upper and lower electrode. Those effects couldn't be analyzed by on dimensional analysis, e.g. Mason equivalent model. The simulation result was confirmed by comparing with the simulation data from Mason model analysis and the measured data of the ZnO FBAR fabricated using micro-machining technique. Also, through the simulation of the area variations of FBAR, it was obtained that the optimum ratio of length and thickness is 20:1 and the minimum ratio is 5:1 to operate thickness vibration mode.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.6 no.3
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• pp.15-23
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• 1995

The antenna height of the mobile communications lower than its typical surroundings causes multipath fading usually resulting in fast fluctuations of both signal strength and wave length in mobile radio communications. Therefore, there have been developed and used various wave be- havior prediction models, in some other foreign countries, based on the measurement data rather than on theoretical derivation. The main purpose of this paper is to examine the wave propagation characteristics particularly in Korean terrain with the measurements made in four types of different areas - a large city area, a small city area, a flat terrain area, and a mountain area. Those areas have been classified according to the terrain characteristics with which the particular area contains, such as scale and number of buildings, highways, trees, and so on. With the measured data of the field strength in the frequency band of pager system obtained from those four different areas, we compared the calculated ones from both Hata's and TIREM prediction models which are often applied in Korea.

• Journal of Society of Preventive Korean Medicine
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• v.15 no.1
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• pp.71-87
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• 2011

Objective : The present study is aimed at providing basic data to help oriental medical hospitals devise efficient operational plans by analyzing the medical expenses of in-patients in an oriental medical hospital and the factors affecting such expenses. Methods : PASW 18.0 was used to analyze the medical insurance program data of 929 patients who were discharged from a university oriental medical hospital(with 105 sick-beds) during the period from January 1 to December 31, 2010 after treatment under the coverage of health insurance and medical aid. Results : 1) Of all the patients hospitalized, 63.3% were females, their mean age was 52.73 years old, and 87.7% was covered by the health insurance program. The biggest number or 31.2% of the patients were treated by the department of acupuncture, 31.5% suffered mainly from the diseases of musculoskeletal system and connective tissues, and the average length of stay at the hospital was 19.49 days. 2) There were statistically significant differences in total medical expenses by age, clinical department in charge, principal diagnosis, and number of days hospitalized while daily average medical expenses differed depending on age, type of medical security, clinical department, principal diagnosis, and number of days staying at the hospital. 3) Total medical expenses were found significantly influenced by age, type of medical security, clinical department, principal diagnosis, and number of days hospitalized(explanatory power : 95.9%), whereas type of medical security, clinical department and principal diagnosis turned out to exercise significant influence on the daily average medical expenses(explanatory power : 26.9%). Conclusion : Oriental medical hospitals are suggested to make efforts to ensure geographical and economical accessibility for their main clients, the elderly and middle-aged, as well as to improve satisfaction of the clients with the medical service provided. They are also encouraged to work out systems to specialize in treatment with a focus on chronic degenerative and adult diseases. In addition, they are expected to try to enhance people's awareness of oriental medicine in an attempt to diversify the brackets of clients and increase frequency of their utilization.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.4
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• pp.528-533
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• 2010

This paper studied the training methods less affected by the emotional variation for the development of the robust speech recognition system. For this purpose, the effect of emotional variation on the speech signal and the speech recognition system were studied using speech database containing various emotions. The performance of the speech recognition system trained by using the speech signal containing no emotion is deteriorated if the test speech signal contains the emotions because of the emotional difference between the test and training data. In this study, it is observed that vocal tract length of the speaker is affected by the emotional variation and this effect is one of the reasons that makes the performance of the speech recognition system worse. In this paper, a training method that cover the speech variations is proposed to develop the emotionally robust speech recognition system. Experimental results from the isolated word recognition using HMM showed that propose method reduced the error rate of the conventional recognition system by 28.4% when emotional test data was used.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.129-136
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• 2023

The study aims to examine the determinants that affect satisfaction, revisit intention, and recommendation intention with foreign tourists who visited Korea despite the threat of COVID-19. This study employs the survey data collected by the Korea Tourism Organization from 8,135 foreign tourists who visited Korea in 2020. As the survey data contains a mixture of continuous and categorical variables, decision tree analysis can ensure analytical validity for the research. According to the analytical results, the determinants affecting satisfaction are the purpose of the visit and acceptance of self-quarantine during their stay. The factors influencing revisit intention are the purpose of the visit, frequency of the visit, and acceptance of self-quarantine during their stay. The determinants affecting recommendation intention are the purpose of the visit, length of stay, and gender. Based on the results of this analysis, this study not only explains the relationship between these determinants and tourism satisfaction, revisit intention, and recommendation intention, but also suggests implications for revitalizing tourism activities.

• Development and Reproduction
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• v.12 no.2
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• pp.169-181
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• 2008

Reproductive ecology of the silver pomfret, Pampus argenteus were investigated by histological observations and morphometric data. Samples were collected by the stow net at the coastal area of Jaun-Do, Muan-gun, Korea, from January to December, 2006. P. argenteus is dioecious, the ovary is composed of many ovarian lobules, showing a pair of saccular structure, and the testis is composed of many seminiferous lobules, showing a pair of lobular structure. From February (growing stage) to September (after spawning), monthly changes in the gonadosomatic index, hepatosomatic index, and condition factor in females and males showed similar patterns with the gonad developmental phases. Judging from the results of their indice, it is assumed that spawning in females and males occur from May to July. The reproductive cycle can be classified into five successive stages in females: early growing stage (February to March), late growing stage (March to April), mature stage (March to July), ripe and spent stage (May to July), and recovery and resting stage (July to February); in males, the cycle can be divided into four successive stages: growing stage (February to April), mature stage (March to June), ripe and spent stage (May to July), and recovery and resting stage (July to February). According to the frequency distributions of egg diameters in the breeding season, P. argenteus is presumed to be spring-summer spawning species and polycyclic species to spawn 2 times or more during one spawning season. Number of total eggs in absolute fecundity were proportional to body length and body weight, respectively. Number of total eggs in absolute fecundity per body weight were also proportional to the body length, but if the increase of body weight considerably increased, rather total eggs in relative fecundity decreased with the increase of body weight. Percentage of first sexual maturity of P. argenteus were over 50% in females and males of 12.1 to 15.0 cm in body length, and 100% for fishes over 18.1 cm in length. Therefore, both sexes were regarded to be sexually mature at one year of age.

• Journal of the Korean Society of Costume
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• v.50 no.2
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• pp.151-165
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• 2000

This study was to find out clothing design preferences, according to the clothing self-image of elderly women and to grasp the variety on clothing of elderly women and thereby to help in merchandise production planning and putting the brands into markets and to provide data for establishing a sales strategy a d to itemize women with the goods which can satisfy the desire and taste of consumer groups in the quality market. For this purpose , various researches as above were conducted .The object of this study was a total of 488 elderly women above full 55 from an elderly women and who lived in downtown Pusan. The data were analysed by using MANOVA, ANOVA , factors analysis and frequency analysis, and the Cronbach α was also applied . The conclusions made based on the theoretical background and the result of questionnaire surveys are as follows ; 1. The realistic self-image of clothing showed a similar pattern by age. 50's and 60's showed little difference by item but 70's was greater in variation between items compared to 60's. The response to each item was that most people answered "common" and they showed a pattern that responded low only in items of 'colorful' , individualistic', 'susceptible to fashion'. A similar pattern was shown by age band also in the ideal self-image and the response to each item appeared higher than in the realistic self-image , and also in items of 'colorful', 'individualistic ' , 'susceptible to fashion' the response appeared low and showed a unity. 2. The results of clothing design preferences examined on the self-image according to age are as follows ; 1) Fro jacket in the realistic self-image , 50's and 60's preferred 'tailed collar' , 'set-in sleeve', 'hips long' and 'plain jacket' and 70's agreed to the design preferences in the items except 'open collar' and also in the idealistic self-image , the degree of preference was same. 2) For skirt in the realistic self-image , 50's and 60's preferred 'tight skirt', 'normal length' , 'plain skirt' and it was appeared that 70's preferred 'pleat skirt' , 'medium length' , 'plain skirt'. Also in the idealistic self-image , the degree of preference was same. 3) For blouse in the realistic self-image, 50's preferred 'open collar', 'round neck line' , 'long set-in sleeve' , 'plain separation belt', 'open front', 'zipper' ad 60's agreed to the favorite designs with 50's except puff sleeve, and 70's appeared to prefer fastening buttons without belt. In the designs preferred in the idealistic self-image, 50's agreed with 50's of the realistic self-image and for 60's , the designs except puff sleeve type and no belt type agreed to 50's and 70's except puff sleeve agreed with 70's of the realistic self-image in their design preferences.