• 한국산학기술학회논문지
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• 제13권10호
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• pp.4506-4513
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• 2012

본 연구의 목적은 중국의 전력소비와 경제성장의 인과관계를 분석하고 그 방향을 확인하여 정책적 시사점을 도출하는 것이다. 이러한 목적을 달성하기위해 1971년~2008년 동안의 연간자료를 사용하여 단위근 검정, 공적분 검정, 오차수정모형을 통한 Granger-인과검정을 하였다. 검정결과 중국의 전력소비와 경제 성장사이에는 장, 단기적 양방향 인과성이 발견되었다. 이러한 결과는 중국의 정책분석가에게 몇 가지 유용한 시사점을 제공한다. 첫째: "경제가 발전하려면 전력이 선행해야 한다."라는 중국의 발전전략이 지금도 유효하다. 즉 전력소비의 증가는 경제성장을 촉진한다. 물론 경제성장에 미치는 다른 요인들이 존재하고 전력은 그 일부분이지만 경제성장을 하기위해서는 안정적인 전력공급이 필요하다. 둘째: 본 연구는 실질 GDP의 증가가 전력소비를 늘린다는 주장도 성립함을 확인하였다. 이는 직관적으로 소득이 늘어나면 보다 많은 전력을 필요로 하는 제품사용이나 수요가 증가할 것이다.

• 아태비즈니스연구
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• 제13권3호
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• pp.183-208
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• 2022

Purpose - The main purpose of this study is to widely investigate the impact of recent pandemic crises on the synchronization of the world capital markets through 25 stock indices from major developed countries. Design/methodology/approach - This study collects 25 stock indices from major developed countries and the time period is between January 5, 2001 and February 24, 2022. The data sets used in the study include finance.yahoo.com and Investing.com.. The Granger causality analysis, unit-root test, VAR analysis, and forecasting error variance decomposition were hired in order to analyze the data. Findings - First, there are significant inter-relations among 25 countries around recent major pandemic crises(such as SARS, A(H1N1), MERS, and COVID19), which is consistent result with previous literature. Second, COVID19 shows much stronger impact on the world-wide synchronization than other pandemics. Third, the return volatility of each stock market varies, unit root tests show that daily stock index data are unstable while daily stock index returns are stable, and VAR(Vector Auto Regression) analyses presents significant inter-relations among 25 capital markets. Fourth, from the impulse response function analyses, we find that each market affects the other markets for short term periods, about 2~4 days, and no long term effect was not found. Fifth, Granger causality tests show one-side or two-sides synchronization between capital markets and we estimate, through forecasting error variance decomposition method, that the explanatory portions of each capital market on other markets vary from 10 to 80%. Research implications or Originality - The above results all together show that pandemic crises have strong effects on the synchronization of world capital markets and imply that these synchronizations should be carefully considered both in the investment decisions by individual investors and in the financial and economic policies by governments.

• Journal of Biosystems Engineering
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• 제22권1호
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• pp.11-20
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• 1997

Thin layer drying tests of short gain rough rice were conducted in an experimental dryer equiped with air conditioning unit. The drying tests were performed in triplicate at three air temperatures of $35^circ$, $45^circ$, $55^circ$, and three relative humidities of 40%, 55%, 70%, respectively. Previously published thin layer equations were reviewed and four different models widely used as thin layer drying equations for cereal grains were selected. The selected four models were Pages, simplified diffusion, Lewis's and Thompson's models. Experimental data were fitted to these equations using stepwise multiple regression analysis. The experimental constants involved in tow equations were represented as a function of temperature and relative humidity of drying air. The results of comparing coefficients of determination and root mean square errors of miosture ratio for low equations showed that Page's and Thompsons models were found to fit adequately to all drying test data with coefficient of determination of 0.99 or better and root mean square error of moisture ratio of 0.025.

• Journal of the Korean Data and Information Science Society
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• 제27권6호
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• pp.1465-1475
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• 2016

안전한 급식을 위해서는 식중독사고와 연관성이 있는 미생물의 위해요소들이 실시간적으로 모니터링 되고 통제되어야 한다. 선진국에서는 실시간 위생 모니터링 도구로 ATP (adenosine triphosphate) Luminometer를 활용한 사례가 여러 건 보고되었다. ATP analyser는 ATP bioluminescence (생물발광성)의 원리를 이용하여 RLU (relatively light unit) 값으로 위생수준을 간접적으로 측정할 수 있게 해준다고 알려져 있다. 이에 국내 급식산업에서도 이를 활용할 수 있도록 조리도구들을 대상으로 일반세균수 (aerobic plate count; APC)와 RLU 간에 상관성이 존재하는지를 확인 할 필요성이 제기 되었다. 본 연구는 급식소의 조리도구 표면에 사전 처리없이 ATP (RLU)와 APC (CFU)를 측정하여 상관관계 존재 여부 파악 및 이들 관계의 최적인 모델을 찾아보고자 하였다. 이들에 대한 분석 결과를 조리도구별로 요약하면 다음과 같다. 도마, 칼, 국그릇 (스텐), 식판 (카보) 자료는 1차 변환의 로그변환이, 컵 자료는 2차 변환의 제곱근-역변환 (혹은 역-제곱근변환)이, 국그릇 (카보) 자료는 2차 변환의 제곱근-제곱근변환이 표준화 회귀계수 및 결정계수 $R^2$가 가장 좋게 나타났으나 식판 (스텐) 자료는 원자료, 1차 변환 및 2차 변환 모든 경우에서 정규성을 만족하지 못하여 이번 자료에서는 최적인 경우를 찾을 수가 없었다.

• Imaging Science in Dentistry
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• 제38권3호
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• pp.169-176
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• 2008

Purpose : To assess the diagnostic accuracy and value in an imaging technique field through the comparison of cone beam computed tomography and conventional panoramic radiography in assessing the topographic relationship between the mandibular canal and impacted third molars. Materials and Methods : Participants consisted of 100 patients offered the images through cone beam computed tomography and panoramic radiography. PSR-$9000^{TM}$ Dental CT system (Asahi Roentgen Ind. Co., Ltd, Japan) was used as the unit of cone beam computed tomography. CE-II (Asahi Roentgen Ind. Co., Ltd, Japan) and Pro Max (Planmeca Oy, Finland) were used as the unit of panoramic radiography. The images obtained through panoramic radiography were classified into 3 types according to the distance between mandibular canal and root of mandibular third molar. And they were classified into 4 types according to the proximity of radiographic feature. The images obtained through cone beam computed tomography based on the classification above were classified into 4 types according to the location between the mandibular canal and the root and were analyzed. And they were classified into buccal, inferior, lingual, and between roots, according to the location between mandibular canal and root. The data were statistically analyzed and estimated by $X^2$-test. Results : 1. There was no statistical significance according to 3 types (type I, type II, type III) through CBCT. 2. The results of 4 types (type A, type B, type C, type D) through CBCT were as high prevalence of CBCT 1 in type A, CBCT 2 in type B, CBCT 3 in type C, and CBCT1 in type D and those of which showed statistical significance (P value=0.03). 3. The results according to location between mandibular canal and root through CBCT recorded each 49, 25, 17, 9 as buccal, inferior, lingual, between roots. Conclusion : When estimating the mandibular canal and the roots through the panoramic radiography, it could be difficult to drive the views of which this estimation was considerable. Thus it is required to have an accurate diagnostic approaching through CBCT that could estimate the location between mandibular canal and roots.

• 수산해양교육연구
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• 제27권6호
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• pp.1745-1754
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• 2015

This study aimed to analyze the relationship between sea temperatures and anchovy catch of Anchovy drag net fishery using annual time series data from 1970 to 2013. In the analysis, time series data on variables (CPUE, sea surface temperature, and 10m temperature) were estimated to be non-stationary from unit root tests, but one long-term equilibrium relation among variables was found from a cointegration test. From an exclusion test, a 10m temperature would not have relations with CPUE and sea surface temperature. The result of regression analysis on sea surface temperature and anchovy catch indicated that the sea surface temperature would have positive impacts on the anchovy catch. It means that when the sea surface temperature would increase, all other things including the current level of fishing effort being equal, the catch of anchovy was predicted to increase. More specifically, the result showed that when 1% of sea surface temperature increases, CPUE would be increased by 2.81%.

• The Journal of Asian Finance, Economics and Business
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• 제6권3호
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• pp.151-162
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• 2019

The paper examines the effects of Foreign Direct Investment (FDI) on the economic growth of Lao People's Democratic Republic (Lao PDR) between 1993 and 2015. The investigation is based on the influence of growth and economic absorptive capability determinants such as human capital, trade openness, and institutional quality. The methodological analysis uses a multivariate framework accounting capital stock, labor stock, FDI, human capital, trade openness, and institutional quality in regression of the Vector Autoregressive model. Augmented Dickey-Fuller unit root test, Johansen Cointegration test, and Granger Causality test were applied as parts of the econometric time-series analysis approach. The empirical results demonstrate the positive effects of FDI and trade openness, and the negative effects of human capital and institutional quality on the economic growth of the Lao PDR over the 1993 to 2015 period. The findings confirm that trade openness complemented by a sufficient level of infrastructure, education, quality institutions, and transparency significantly influence economic growth and attract more FDI. Research results lend credence to the need for the Lao PDR's government to focus on improving its economic absorptive capability and economic competitiveness regionally and globally by improving wealth and resource management strategies, as failure to take this course of action could lead to the Dutch Disease effects.

• The Journal of Asian Finance, Economics and Business
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• 제7권9호
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• pp.219-228
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• 2020

The study investigates the impact of inflation rate on economic growth to find the best-fit model for economic growth in Vietnam. The study applied Vector Autoregressive (VAR), cointegration models, and unit root test for the time-series data from 1996 to 2018 to test the inflation impact on the economic growth in the short and long term. The study showed that the two variables are stationary at lag first difference I(1) with 1%, 5% and 10%; trace test indicates two cointegrating equations at the 0.05 level, the INF does not granger cause GDP, the optimal lag I(1) and the variables are closely related as R2 is 72%. It finds that the VAR model's results are the basis to perform economic growth; besides, the inflation rate is positively related to economic growth. The results support the monetary policy. This study identifies issues for Government to consider: have a comprehensive solution among macroeconomic policies, monetary policy, fiscal policy and other policies to control and maintain the inflation and stimulate growth; set a priority goal for sustainable economic growth; not pursue economic growth by maintaining the inflation rate in the long term, but take appropriate measures to stabilize the inflation at the best-fitted VAR forecast model.

• 경영과학
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• 제25권3호
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• pp.13-26
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• 2008

We investigate the effect of government and public sector R&D Investment at IT Industry on the amount of Production, export and nongovernment R&D Investment at IT Industry. We, firstly, examine the stationarity of each variable by the unit root t-test and perform the co-integration test for the pairs of variables. We use YECM(Vector Error Correction Model) according to the results of co-integration test for the examination of Granger-causality between variables. It is found that there exist an Granger-causality between public sector R&D Investment and nongovernment R&D investment and also between public sector R&D Investment and export. Secondly, we analyze the impulse response of government and public sector R&D Investment at IT Industry on the amount of production, export and nongovernment R&D investment at IT Industry based on VECM model. It is found that the response of the amount of production is highest at 3th period and is lowest at 8th period and that of export shows similar pattern.

• 수산경영론집
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• 제46권1호
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• pp.93-107
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• 2015

This study aims to analyze causalities among Hairtail prices by distribution channel using a vector autoregressive model. This study applies unit-root test for stability of data, uses Granger causality test to know interaction among Hairtail Prices by distribution channel, and employes the vector autoregressive model to estimate statistical impacts among t-2 period variables used in model. Analyzing results of this study are as follows. First, ADF, PP, and KPSS tests show that the change rate of Hairtail price by distribution channel differentiated by logarithm is stable. Second, a Granger causality test presents that the producer price of Hairtail leads the wholesale price and then the wholesale price leads the consumer price. Third, the vector autoregressive model suggests that the change rate of Hairtail producer price of t-2 period variables statistically, significantly impacts change rates of own, wholesale, and consumer prices at current period. Fourth, the impulse response analysis indicates that impulse responses of the structural shocks with a respectively distribution channel of the Hairtail prices are relatively more powerful in own distribution channel than in other distribution channels. Fifth, a forecast error variance decomposition of the Hairtail prices points out that the own price has relatively more powerful influence than other prices.