• Survey Research
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• v.5 no.1
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• pp.27-49
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• 2004

Recently, in several countries including South Korea, the percentage of households having fixed telephones, which is often called the fixed telephone coverage rates, has decreased due to a rapid spread of mobile phones. It is generally assumed that the lower the rates of coverage, resulting in a major frame undercoverage problem, the greater the possibility of the bias. In this paper, we first take a look at the changes of coverage rates in both fixed telephones and mobile phones in South Korea and examine the coverage rates by sociodemographic characteristics of households. Also, we refer to a change in the level of fixed telephone noncoverage and the resulting problems in the situation. Second, we provide a comparison of the coverage rates for households for some European countries, the United States, Canada etc. Finally, we suggest further research to rise to our research environments increasingly troublesome, owing to the wide spread of mobile phones.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12A
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• pp.1311-1319
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• 2007

This paper presents the VHDL implementation procedure of the passive RFID tag operating in Ultra High Frequency. The operation of the tag compatible with the EPCglobal Class1 Generation2(GEN2) protocol is verified by timing simulation after synthesis and implementation. Due to the reading range with relatively large distance, a passive tag needs digital processor which facilitates faster decoding, encoding and state transition for enhancement of an interrogation rate. In order to satisfy linking time, the pipe-line structure is used, which can minimize latency to serial input data stream. We also propose the sampling strategy to decode the Preamble, the Frame-sync and PIE symbols in reader commands. The simulation results with the fastest data rate and multi tags environment scenario show that the VHDL implemented tag performs faster operation than GEN2 proposed.

• Journal of Power Electronics
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• v.16 no.3
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• pp.1110-1121
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• 2016

The mathematical model of a three phase PWM converter under the stationary αβ reference frame is deduced and constructed based on a Proportional-Resonant (PR) regulator, which can replace trigonometric function calculation, Park transformation, real-time detection of a Phase Locked Loop and feed-forward decoupling with the proposed accurate calculation of the inductance voltage vector. To avoid the parallel resonance of the LCL topology, the active damping method of the proportional capacitor-current feedback is employed. As to current vector error elimination, an optimized PR controller of the inner current loop is proposed with the zero-pole matching (ZPM) and cancellation method to configure the regulator. The impacts on system's characteristics and stability margin caused by the PR controller and control parameter variations in the inner-current loop are analyzed, and the correlations among active damping feedback coefficient, sampling and transport delay, and system robustness have been established. An equivalent model of the inner current loop is studied via the pole-zero locus along with the pole placement method and frequency response characteristics. Then, the parameter values of the control system are chosen according to their decisive roles and performance indicators. Finally, simulation and experimental results obtained while adopting the proposed method illustrated its feasibility and effectiveness, and the inner current loop achieved zero static error tracking with a good dynamic response and steady-state performance.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.5
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• pp.573-581
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• 2002

This study was done to classify children's somatotypes and to provide the fundamental data or their clothing sizing system for the purpose of designing patterns fur children's wear and standardizing sizes of ready-made clothes. The sampling was done for 7-8 years-old-girl living in Pusan and Kyungsangnam-do. Data from each girl comprises 33 anthropometic measurments and 7 photogrphic measurments, based on the somatometric characteristics of girls which I had obtained. Factor analysis, cluster analysis, discriminant analysis were performed for statistical analysis of the data. Seven factors which explain 76.49% of the whole variances were extracted. The thirst and second factors which explain more than 70% of the whole variances represent 'horizontal size 'and 'vortical size', which characterize most aspects of the body shape of the subjects. On the basis of the cluster analysis, three different upper body types were categorized. Type 1 has quite long surface length of the upper body and rising shoulders and are close to the averages of this age group. Type 2 has highest stature, biggest frame, dropped shoulders and surface length of the upper body similar to the type 1. Type 3 has shortest stature, smallest frame and sloping shoulders. According to the analysis to discriminate somatotypes of the upper body by this age group, the discriminative items in discriminant function are follows. As this group, waist circumference of discriminant function 1 and front length and length between both shoulder points of discriminant function 2 have large coefficient values.

• The Journal of the Acoustical Society of Korea
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• v.27 no.4
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• pp.200-206
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• 2008

This paper presents a method of quantization to extract quantization parameters using the straight-line and DCT (Discrete Cosine Transform) for two splited frequency bands. As the number of harmonic is variable frame to frame, harmonics in low frequency band is oversampled to fix the dimension and straight-lines present a spectral envelope, then the discontinuous points of straight-lines in low frequency is sent to quantizer. Thus, extraction of quantization parameters using the straight-line provides a fixed dimension. Harmonics in high frequency use variable DCT to obtain quantization parameters and this paper proposes a method of quantization combining the straight-line with DCT. The measurement (If proposed method of quantization uses spectral distortion (SD) for spectral magnitudes. As a result, The proposed method of quantization improved 0.3dB in term of SD better than HVXC.

• Journal of the Korean Society of School Health
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• v.17 no.1
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• pp.85-95
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• 2004

Objectives : The aim of this study was to identify the trend of school health research by analyzing articles related to school health for the last 10 years. this information can be used to guide research direction for the future. Methods : This study is a descriptive study that analyzed annual data. using an objective frame of evaluation about the methodology and research domain in each paper, all the papers included in the journals concerning school health from January 1993 to December 2000 were analyzed. The data was processed statistically by frequency and percentage. Results : 455 papers in 9 journals related to school health were published. The Journal of the Korean Society of School Health had 204 articles, the highest number of any journal. most of the articles were descriptive, but the number of experimental studies increased over time. the most common research subjects were students were the greatest ones, but the trend to study both parents and teachers increased near the end of the sampling period. the most common selection of subjects appeared to be based on convenience, but probability sampling gradually increasing annually. the most common research instrument was the questionnaire and the reliability and the validity of instruments were described in approximately half of the studies. The survey was the most commonly used method of data collection. The papers that met ethical issue in data collection were less than those that did not. In addition, the papers that provided the rationale for the calculation of sample size were less than those that did not. parametric statistics were the main methods of data analysis, but some advanced statistics were used more often than simple descriptive statistics in the latter part of the sampling period. In general, limit of the studies were not frequently mentioned but more recommendations were made. regarding the characteristics of the research area, the assesment domain was remarkable. The rate of school health problem assesment was the highest among research subjects. Sex- related subjects were the highest in detail research subjects. Conclusions : The research of school health has increased quantitatively, but it is difficult to ascertain its qualitative development. Therefore, on the basis of the research completed up until now, more school-based intervention studies and longitudinal studies need to be another target for the evaluation of the effects of the school health service. as well, policy suggestion through international and cross-sectional comparison studies are needed to assist in the establishment of the long term direction of school health.

• Journal of the Korean Applied Science and Technology
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• v.37 no.2
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• pp.303-317
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• 2020

The purpose of this study is to conceptualize the process of formation by the exploration of the lives of professional golfers who grow to excellent sports leaders, categorize the concept and suggest models between categories. In order to reveal in depth the change process of the job formation, the 'grounded approach' as a qualitative study was used as a the methodological frame of this study, and snow sampling, one of nonrandom sampling was used for the selection method of the study participants. 10 study participants who are able to make positive self-expression and talk with the researcher were selected. Through grounded approach appropriate for this process research, this study could acquire following results. First, through the casual condition that is the exploration of the lives of professional golfers growing to excellent sports leaders, it connected to the central phenomena of professional instruction methods and education belief as golf leaders. In this process, the changes as new experiences for the charm of the new job and relationship formation influence as the function of a contextual condition. In addition, golf leaders tried to become a more completed golf leader through self-efforts for development and expertise attainment according to the their own situations as well as belief, and they have established the lives of firm golf leaders through the process. Second, as a result of the changes of their lives as professional golfers growing to excellent sports leaders, the paradigm of grounded approach which is abstracted as total 141 concepts, 17 subcategories, and 11 superordinate categories were composed.

• Korean journal of communication and information
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• v.45
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• pp.425-462
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• 2009

The present study delves into how rape reports are framed in popular Korean newspapers over time. Specifically, the primary purpose of this study was to examine how rape myths and ambivalent sexism and were presented in three Korean newspapers. In order to assess longitudinal trends of rape reports, the sample for the content analysis was drawn from 1990 to 2007. Four newspapers, Chosun-Ilbo, Dongah-Ilbo, Jungang-Ilbo and Hankyoreh, which have been the most popular in terms of circulation and ad revenues, were selected for this longitudinal content analysis. Using random stratified sampling and screening process, A total of 2160 articles were content analyzed for the main study. The results revealed that rape reports appearing in Korean newspapers were overwhelmingly dominated by episodic frame rather than thematic frame. Particularly, It was found that Korean rape reports generally have attributed the cause of rape crimes to the victims. Implications for results were discussed in terms of rape myth and ambivalent sexism theories.

• Journal of the Korea Society of Computer and Information
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• v.16 no.7
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• pp.67-76
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• 2011

Recently, researches for semantic annotation methods which represent and search objects included in video data, have been briskly activated since video starts to be popularized as types for interactive contents. Different location data occurs at each frame because coordinates of moving objects are changed with the course of time. Saving the location data for objects of every frame is too ineffective. Thus, it is needed to compress and represent effectively. This paper suggests two methods; the first, ontology modeling for moving objects to make users intuitively understandable for the information, the second, to reduce the amount of data for annotating moving objects by using cubic spline interpolation. To verify efficiency of the suggested method, we implemented the interactive video system and then compared with each video dataset based on sampling intervals. The result follows : when we got samples of coordinate less than every 15 frame, it showed that could save up to 80% amount of data storage; moreover, maximum of error deviation was under 31 pixels and the average was less than 4 pixels.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.724-731
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• 2016

As the structural damage caused by earthquakes has been gradually increasing, estimating the seismic fragility of structures has become essential for earthquake preparation. Seismic fragility curves are widely used as a probabilistic indicator of structural safety against earthquakes, and many researchers have made efforts to develop them in a more accurate and effective manner. However, most of the previous research studies used simplified 2D analytical models when deriving fragility curves, mainly to reduce the numerical simulation time; however, in many cases 2D models are inadequate to accurately evaluate the seismic behavior of a structure and its seismic vulnerability. Thus, this study provides a way to derive more accurate, but still effective, seismic fragility curves by using 3D analytical models. In this method, the reliability analysis software, FERUM, is integrated with the structural analysis software, ZEUS-NL, enabling the automatic exchange of data between these two software packages, and the first order reliability method (FORM), which is not a sampling-based method, is utilized to calculate the structural failure probabilities. These tools make it possible to conduct structural reliability analyses effectively even with 3D models. By using the proposed method, this study conducted a seismic vulnerability assessment of RC frame structures with their 3D analytical models.