• 한국전자파학회논문지
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• 제11권5호
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• pp.813-821
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• 2000

위성통신 경로의 강우감쇠량을 예측하기 위하여 국제적으로 여러 가지 예측모델들이 개발 운용되고 있다. 이러한 예측 모델들은 대부분 미국과 유럽을 비롯한 위성 선진국에서 개발한 것으로 국내의 강우환경을 고려하여 개발된 모델은 없는 실정이다. 본 논문에서는 한국전자통신연구원에서 측정한 강우환경 및 강우감쇠 데이터를 이용하여, 국내 위성통신망에서 고려할 수 있는 강우감쇠량 예측 방법에 대해 기술하였다. 특히, 기존 예측 모델들이 적용한 강우경로의 수평적 변화를 고려한 유효경로 길이 예측 기법에서 탈피하여, 위성통신망에서 필연적으로 고려하여야 할 강우경로의 수직적 변화까지도 고려한 유효경로 예측기법을 유도하고 이를 제안하였다. 본 논문에서 제안한 예측 기법은 국내 강우환경에 적합한 예측 기법으로써, 향후 설계 및 운용될 10GHz 이상의 국내 위성 및 무선통신시스템에 매우 효율적으로 활용할 수 있을 것이다. ^u The engineering of satellite communication systems at frequencies above 10GHz requires a method for estimating rain-caused outage probabilities on the earth-satellite path. A procedure for predicting a rain attenuation distribution from a point rainfall rate distribution is, therefore, needed. In order to predict rain attenuation on the satellite link, several prediction models such as ITU-R, Global, SAM, DAH model, have been developed and used at a particular propagation condition, they may not be appropriate to a propagation condition in Korean territory. In this paper, a new rain attenuation prediction method appropriate to a propagation condition in Korea is introduced. Based on the results from ETRI measurements, a new method has been derived for an empirical approach with an identification on the horizontal correction factor as in current ITU-R method, and the vertical correction factor has been suggested with decreasing power law as a function of rainfall rate. This proposed model uses the entire rainfall rate distribution as input to the model, while the ITU-R and DAH model approaches only use a single 0.01% annual rainfall rate and assume that the attenuation at other probability levels can be determined from that single point distribution. This new model was compared with several world-wide prediction models. Based on the analysis, we can easilty know the importance of the model choice to predict rain attenuation for a particular location in the radio communication system design.

• 국제물리치료학회지
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• 제4권2호
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• pp.573-587
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• 2013

The purpose of this study was conducted in order to analyze the effects of the manual intervention and self-corrective exercise models of general coordinative manipulation(GCM) on the balance restoration of spine & extremities joints with distortions and mal-alignment areas. The subjects were the members who visited GCM Musculoskeletal Prevent Exercise Center from March 1 2012 to December 31 2013 because of spine & extremities joints distortion and mal-alignments, poor posture, and body type correction. All subjects were diagnosed with the four types of the GBT diagnosis. And according to the standards of the mobility vs stability types of the upper & lower body, they were classified into Group 1(40 persons) and Group 2(24 persons). For every other day for three times a week, GCM intervention models were applied to all subjects for four weeks, adding up to 12 times in total. Then the balance restoration effects were re-evaluated with the same methods. The results are as follows. 1) Balance restoration effects of VASdp(Visual analysis scale pain & discomfort) and ER(Equilibrium reaction: ER) came out higher in GCM body type(GBT) II III IV of Group 1. 2) In case of balance restoration effects in Moire and postural evaluation areas, Group 1 was higher and cervical and scapular girdle were higher in Group 2. The balance restoration of the four GBT types was significant in all regions(p<.05), and the scapular girdle came out as high in the order of GBTII IV I. 3) In case of thoracic-lumbar scoliosis and head rotation facial asymmetric cervical scoliosis ribcage forward, the balance restoration effects of the upper body postural evaluation areas came out the highest in Group 1 and Group 2, respectively. The balance restoration effects of the four GBT types were significant in all regions(p<.05), and came out the highest in lumbar scoliosis GBTIII I, ribcage forward and thoracic scoliosis GBTII IV. 4) The balance restoration effects of the lower body postural evaluation areas came out higher in Group 1 and Group 2 for pelvis girdle deviation patella high umbilicus tilt and hallux valgus foot longitudinal arch: FLA patella direction, respectively. The balance restoration effects of the four GBT types were significant in all regions(p<.05), and came out the highest in pelvis girdle deviation GBTIII I and patella high-direction GBTIV II I. 5) The balance restoration effects between the same GBT came out significant (p<.05) in all evaluation areas and items. The conclusions of this study was the manual intervention and self-corrective exercise models of the GCM about the mal-alignment of the spine & extremities joints across the whole body indicated high balance restoration effects(p<.05) in spine & extremities joints in all evaluation areas.

• 수산경영론집
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• 제41권2호
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• pp.107-133
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• 2010

As policy makers are often concerned about dynamic effects of demand behavior and its welfare analysis by quantity changes, the paper shows how dynamic price formation systems can be built up to analyze the effect of policy options to the markets dynamically. The paper develops dynamic model of price formation for fish from the intertemporal optimization of the consumer choice problem. While the resulting model has a similar form of the error correction types of dynamic price formation system, it provides the rational demand behavior contrary to the myopic behavior of error correction demand models. The paper also develops appropriate tools of dynamic welfare analysis in quantity space using only short-run demand estimates both theoretically and empirically as a first attempt in the literature of price formation and fisheries. The empirical results of Korean fish markets show that the dynamic model and the welfare measures are reasonably plausible. The methodology and theory of this research can be applied and extended to the commodity aggregation, dynamic demand estimation, and dynamic welfare effects of regulation in the similar framework. Thus, it is hoped that this will enhance its applications to the demand-side economics.

• 지역연구
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• 제33권3호
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• pp.3-19
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• 2017

본 연구의 목적은 지역의 산업다양성이 지역의 경기변동에 어떤 영향을 주는지를 분석하는 데 있다. 지역의 경기변동은 고용시장과 생산활동의 측면에서 측정하였고 2005년 1월부터 2016년 2월을 분석기간으로 설정하였다. 우리나라의 주요 항만도시를 대상으로 선정하였고 지역의 특성을 통제하기 위하여 패널 벡터오차수정모형의 그룹평균 추정량과 통합그룹평균 추정량을 사용하였다. 산업의 구성이 다양한 지역에서는 단기적으로 실업률의 변동의 폭이 작았지만, 제조업 생산지수의 변동성은 장기적인 경우에만 낮게 나타났다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.589-592
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• 2005

Gravity characteristics and Moho undulations are investigated in the Korean peninsula by using satellite gravity data. According to the development of satellite geodesy, gravity potential models which have high accuracy and resolution were released. Using the EIGEN-CGOIC model based on low orbit satellite data such as CHAMP and GRACE, geoid and gravity anomaly were calculated by spherical harmonic analysis. The study area is located at $123^{\circ}\sim132^{\circ}E, 33^{\circ}\sim43^{\circ}$N including Korea. Free-air anomalies, which show the effect of terrain, have the values between $-37\sim724 mgal. After Bouguer correction, the range of simple Bouguer anomalies is $-221\sim246$ mgal. Complete Bouguer anomalies after terrain correction increase from continent to marine. This phenomenon is related rise of Moho discontinuity. The cut-frequency for extraction of Moho undulation was determined by power spectrum analysis, and then 3D inversion modeling was implemented. The mean, maximum, minimum, and standard deviation of Moho depth undulation are -26, -36, -8, and 4.9 krn, respectively.

• 노동경제논집
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• 제34권3호
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• pp.59-80
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• 2011

본 연구는 비안정적 시계열 자료 분석 방법을 이용하여 장단기 고용탄력성을 추정하고 그 변화를 고찰하였다. 그 결과, 지난 25년간 고용탄력성이 유의하게 감소했다는 증거를 발견할 수 없었다. 이는 외환위기 이후의 취업자 수 증가율 감소가 고용탄력성 감소보다는 성장률 감소에 크게 기인함을 의미한다. 그러므로 일자리 창출력을 높이려는 정책적 노력은 성장잠재력 강화에 경주되어야 한다. 통계적 유의성을 떠나 고용탄력성 감소경향을 사실로 받아들인다고 하더라고 그것은 장기적으로 영향력을 발휘하는 구조적 요인에 기인하는 것이다. 그러므로 주어진 성장률 아래에서 일자리 창출력을 높이기 위한 노력도 장기적인 체질 강화에 역점을 두어야 한다.

• The Journal of Asian Finance, Economics and Business
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• 제7권1호
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• pp.37-46
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• 2020

The paper examines the dynamic relationship of domestic credit and stock market liquidity on the economic growth of the Philippines from 1995 to 2018 applying the autoregressive distributed lag (ARDL) bounds testing approach to cointegration, together with Granger causality test based on vector error correction model (VECM). The ARDL model indicated a long-run relationship of domestic credit and stock market liquidity on GDP growth. When the GDP per capita is the dependent variable there is weak cointegration. Also, the Johansen cointegration test confirmed the existence of long-run relationship of domestic credit and stock market liquidity both on GDP growth and GDP per capita. The VECM concludes a long-run causality running from domestic credit and stock market liquidity to GDP growth. At levels, domestic credit has significant short-run causal relationship with GDP growth. As for stock market liquidity at first lag, has significant short-run causal relationship with GDP growth. With regards to VECM for GDP per capita, domestic credit and stock market liquidity indicates no significant dynamic adjustment to a new equilibrium if a disturbance occurs in the whole system. At levels, the results indicated the presence of short-run causality from stock market liquidity and GDP per capita. The CUSUMSQ plot complements the findings of the CUSUM plot that the estimated models for GDP growth and GDP per capita were stable.

• Wind and Structures
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• 제8권3호
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• pp.213-233
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• 2005

Wind uplift rating of roofing systems is based on standardized test methods. Roof specimens are placed in an apparatus with a specified table size (length and width) then subjected to the required wind load cycle. Currently, there is no consensus on the table size to be used by these testing protocols in spite of the fact that the table size plays a significant role in wind uplift performance. Part I of this paper presented a study with the objective to investigate the impact of table size on the performance of roofing systems. To achieve this purpose, extensive numerical experiments using the finite element method have been conducted and benchmarked with results obtained from the experimental work. The present contribution is a continuation of the previous research and can be divided into two parts: (1) Undertake additional numerical simulations for wider membranes that were not addressed in the previous works. Due to the advancement in membrane technology, wider membranes are now available in the market and are used in commercial roofing practice as it reduces installation cost and (2) Formulate a logical step to combine and generalize over 400 numerical tests and experiments on various roofing configurations and develop correction factors such that it can be of practical use to determine the wind uplift resistance of roofs.

• Journal of Biosystems Engineering
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• 제38권3호
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• pp.192-198
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• 2013

Purpose: Methods for non-destructive estimation of product quality have been reported in various industrial fields, but the application of ultrasonic techniques for the agricultural products of potatoes, pears, apples, watermelons, kiwis and tomatoes etc. have been rarely reported since the application of a contact-type ultrasonic transducer in agricultural products is very difficult. Therefore, this study sought to determine the firmness of apples using non-contact ultrasonic techniques. Methods: For this experiment, an ultrasonic experimental tester using a non-contact ultrasonic transducer was created, and a signal processing program was used to analyze the acquired ultrasonic reflected signal. Also, a universal testing machine was used to measure firmness parameters of the apples such as bioyield strength, a firmness factor, after the ultrasonic tests had been performed. Results: Six distance correction factors were calculated to obtain consistent values of ultrasonic properties regardless of the distance between the transducer and the surface of the subject. We developed prediction models of the bioyield strength using the distance correction factors. Conclusions: The optimum prediction model of the bioyield strength of apples using a non-contact ultrasonic technique was a multiple regression model ($R^2=0.9402$).

• International Journal of Aerospace System Engineering
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• 제3권1호
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• pp.10-16
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• 2016

A trigonometric Layerwise higher order shear deformation theory (TLHSDT) is developed and implemented for free vibration and buckling analysis of laminated composite and sandwich plates by analytical and finite element formulation. The present model assumes parabolic variation of out-plane stresses through the depth of the plate and also accomplish the zero transverse shear stresses over the surface of the plate. Thus a need of shear correction factor is obviated. The present zigzag model able to meet the transverse shear stress continuity and zigzag form of in-plane displacement continuity at the plate interfaces. Hence, botheration of shear correction coefficient is neglected. In the case of analytical method, the governing differential equation and boundary conditions are obtained from the principle of virtual work. For the finite element formulation, an efficient eight noded $C^0$ continuous isoparametric serendipity element is established and employed to examine the dynamic analysis. Like FSDT, the considered mathematical model possesses similar number of variables and which decides the present models computationally more effective. Several numerical predictions are carried out and results are compared with those of other existing numerical approaches.