• Communications for Statistical Applications and Methods
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• 제21권4호
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• pp.335-347
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• 2014

This paper employs dynamic conditional correlation (DCC) model to examine time-varying comovement in the Korean stock market with a focus on the financial industry. Analyzing the daily returns of KOSPI 200 eight sector indices from January 2008 to December 2013, we find that stock market correlations significantly increased during the GFC period. The Financial Sector had the highest correlation between the Constructions-Machinery Sector; however, the Consumer Discretionary and Consumer Staples sectors indicated a relatively lower correlation between the Financial Sector. In terms of model fitting, the DCC with t distribution model concludes as the best among the four alternatives based on BIC, and the estimated shape parameter of t distribution is less than 10, implicating a strong tail dependence between the sectors. We report little asymmetric effect in correlation dynamics between sectors; however, we find strong asymmetric effect in volatility dynamics for each sector return.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1993년도 Proceedings of International Conference for Agricultural Machinery and Process Engineering
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• pp.98-107
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• 1993

Domestic production of agricultural machinery has come to be seen as appropriate entry route in the capital goods industry for most African countries, including Ghana, which has purely and strongly agricultural -based economics with a weak industrial infrastructure. Recent studies in Ghana do indicate that in addition to possessing technological capability in the manufacture of handtools, there is evidence of increased production of machinery for the primary food processing sector. Local manufacture of tractors and associated implements is embryonic, with an average domestic production of agricultural machinery in Ghana and analyses the available technologies and economic indicators in the local agricultural machinery industry. Areas for indicators in the local agricultural machinery industry. Areas for future development are identified.

• Journal of Biosystems Engineering
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• 제33권1호
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• pp.14-20
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• 2008

An agricultural unmanned helicopter was suggested for an alternative to current pesticide application methods to solve such problems as high cost, low efficiency, shirking task and unsafe work. To pursuit this trend, researches on the development of unmanned helicopters have been accelerated in Korea as well. In this research, a guide type centrifugal clutch that plays an important role in the unmanned helicopter was studied. Theoretical analyses and experimental tests were conducted for designing an optimal clutches. Main design factors of the guide type centrifugal clutch were found to be spring constant, free length of spring, mass of friction sector, contact area, allowable pressure, number of friction sector, friction coefficient, radius of drum, and clutch arrangement. And these design factors could be the functions of engaging engine speed and desired power transfer capacity. The result of the single clutch test showed the power transfer capacity of 14.1 PS at 5,800 rpm and the result of the dual clutch test showed that the capacity of 17.7 PS at 5,600 rpm. These experimental results agreed well the theoretical simulations.

• Journal of Biosystems Engineering
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• 제40권3호
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• pp.238-249
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• 2015

Purpose: Fruit and vegetable production is a fast-growing sector in East Africa, and it bears considerable local and international market potential. In an effort to analyze the challenges within this sector and suggest possible solutions, this study reviews the postharvest handling technologies commonly used with fruits and vegetables in East Africa. Methods: During the course of this study, small-scale farmers were identified as the most prominent producers of fruit and vegetable crops in the region. Results: We found that many of these small-scale farmers employed relative simple and inexpensive techniques in handling their limited volumes of produce. Several factors could be addressed to reduce postharvest losses, including weak policies, inferior infrastructure, and poor market strategies. However, the lack of basic knowledge (including demographic, scientific, and economic knowledge) among the stakeholders (e.g., researchers, farmers, governments, nongovernment organizations, and merchants) on how to develop, implement, use, and sustain the recommended handling technologies is probably the most problematic. Conclusions: We recommend that high priority be placed on closing the knowledge gap, which could enhance the efforts of all the stakeholders to address and reduce postharvest losses.

• 공학교육연구
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• 제13권4호
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• pp.93-108
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• 2010

이 연구는 기계분야 직무체계 개발과 국가기술자격종목 연계실태 분석에 목적이 있다. 문헌연구, 면담조사, 전문가협의회를 통해 산업현장에서 통용되는 용어를 중심으로 직무를 분류하고 직무수준을 설정하였다. 직무분류 결과 기계분야의 직무군은 크게 중분류 3개, 소분류 11개, 이들 소분류를 다시 분류하면 총 42개의 직무가 도출되었다. 기계분야의 직무수준은 국가자격체제(KQF)의 수준체계와 자격 및 교육과정, 산업 현장의 직무별 수준을 반영하여 7단계로 구분하였다. 도출된 직무 체계를 바탕으로 직무군과 직무 정의를 제시하였으며, 각 직무별 정의와 직무별 수준별 수행기준을 도출하였다. 또한 개발된 직무체계와 국가기술자격 종목과의 연계실태를 분석하여 자격종목 개선방안을 제시하였다.

• 기술혁신연구
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• 제9권2호
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• pp.56-76
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• 2001

The main purpose of this study is to analyse the digital divide and th determinants of ICT diffusion rate in Korean industries. We estimate the ICT diffusion function using the pooling data for this analysis. The results are as follows. First, the ICT capital accumulated in machinery & equipment, electrical machinery and construction industry is estimated to be 83% of total In capital stock in the 90s. Second, using the panel analysis, we find positive correlation among ICT diffusion, network effect and accumulation of human capital, which is more prominent in the service sector. Third, the estimation results show that the additional 1% increase of human capital accumulation will allow to increase the 0.69% of ICT capital intensity in Korean industries.

• Journal of Biosystems Engineering
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• 제41권2호
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• pp.116-125
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• 2016

Background: Microfluidics is of considerable importance in food and agricultural industries. Microfluidics processes low volumes of fluids in channels with extremely small dimensions of tens of micrometers. It enables the miniaturization of analytical devices and reductions in cost and turnaround times. This allows automation, high-throughput analysis, and processing in food and agricultural applications. Purpose: This review aims to provide information on the applications of microfluidics in the agro-food sector to overcome limitations posed by conventional technologies. Results: Microfluidics contributes to medical diagnosis, biological analysis, drug discovery, chemical synthesis, biotechnology, gene sequencing, and ecology. Recently, the applications of microfluidics in food and agricultural industries have increased. A few examples of these applications include food safety analysis, food processing, and animal production. This study examines the fundamentals of microfluidics including fabrication, control, applications, and future trends of microfluidics in the agro-food sector. Conclusions: Future research efforts should focus on developing a small portable platform with modules for fluid handling, sample preparation, and signal detection electronics.

• Journal of Biosystems Engineering
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• 제34권2호
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• pp.89-94
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• 2009

Aerial application using an agricultural unmanned helicopter was suggested for an alternative against current pesticide application methods. Centrifugal clutches play important roles in the performance and safety of the helicopter operation. A previous study analyzed and verified the power transfer theory of the guide type centrifugal clutch. Based on the clutch theory, optimal designs of the clutch became possible and feasible using a simulation method. Design criteria of the clutch were the power transfer capacity of 24.66 kW(33.5 PS) at the rated engine speed and the engaging range speed of 3,000${\sim}$3,500 rpm. Various designs were accomplished using the simulation. An optimal clutch was simulated by determining the values of spring constant and mass of friction sector, which were 94,700 N/m and 123.7 g, respectively. The design performed the power capacity of 24.86 kW(33.8 PS) and engagement speed of 3,069 rpm, meeting the design criteria. Using the designed clutch, an efficient transfer of the power would be possible for the unmanned agricultural helicopter.

• Asian Journal of Innovation and Policy
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• 제3권1호
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• pp.50-71
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• 2014

This paper is an attempt to understand the external technology acquisition (ETA) process of the machinery SME sector in Bangalore city, India. With the onset of economic liberalization, Bangalore based machinery SMEs have significantly shifted their ETAs from India to abroad, particularly Germany and Japan, among others. The primary objective of ETAs is to enhance their competitiveness by means of improving product quality and productivity as well as meeting customer demand. Replacing outdated machinery or overcoming technological obsolescence is a primary objective of only a few. As a result, majority of the SMEs has gone for multiple ETAs since their inception and we found a statistically significant positive correlation between firm age and number of ETAs. The present study has made two empirical contributions: (i) We have thrown light on the core technology up-gradation issue - How do SMEs approach the problem of external technology acquisition in the current globalization era? (ii) We are able to identify and develop a map of ETA process based on the "learning and experiences" of these SMEs.

• Journal of Biosystems Engineering
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• 제40권3호
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• pp.186-192
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• 2015

Background: Various solar energy collecting systems have been developed and analyzed for agricultural applications. They include solar thermal and electric devices such as solar crop dryers, solar water pumps, solar greenhouse heating, ventilation for livestock, solar aeration pumps, solar electricity, and many more. Purpose: This review provides the current status of research and development in the field as well as the solar energy systems that are currently in use in the agriculture sector across the globe. Review: Solar energy is the largest and cheapest energy resource on earth; one hour of solar radiation exceeds the complete global energy consumption in one year. The potential annual total solar radiation in South Korea is $3.58-5.4 kWh/m^2/day$. The available solar energy is sufficient for agricultural applications across the entire country. Conclusion: The scope of solar energy utilization in agricultural machinery engineering in South Korea and in other countries is promising.