• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.6
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• pp.43-54
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• 2018

The accurate estimation of reference crop evapotranspiration ($ET_o$) is essential in irrigation water management to assess the time-dependent status of crop water use and irrigation scheduling. The importance of $ET_o$ has resulted in many direct and indirect methods to approximate its value and include pan evaporation, meteorological-based estimations, lysimetry, soil moisture depletion, and soil water balance equations. Artificial neural networks (ANNs) have been intensively implemented for process-based hydrologic modeling due to their superior performance using nonlinear modeling, pattern recognition, and classification. This study adapted two well-known ANN algorithms, Backpropagation neural network (BPNN) and Generalized regression neural network (GRNN), to evaluate their capability to accurately predict $ET_o$ using daily meteorological data. All data were obtained from two automated weather stations (Chupungryeong and Jangsu) located in the Yeongdong-gun (2002-2017) and Jangsu-gun (1988-2017), respectively. Daily $ET_o$ was calculated using the Penman-Monteith equation as the benchmark method. These calculated values of $ET_o$ and corresponding meteorological data were separated into training, validation and test datasets. The performance of each ANN algorithm was evaluated against $ET_o$ calculated from the benchmark method and multiple linear regression (MLR) model. The overall results showed that the BPNN algorithm performed best followed by the MLR and GRNN in a statistical sense and this could contribute to provide valuable information to farmers, water managers and policy makers for effective agricultural water governance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.555-563
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• 2020

This study aimed to distinguish between predisposing factors influencing the entrepreneurial intentions of university and college students who completed an entrepreneurship education course and to empirically determine the relationship between entrepreneurial intention and entrepreneurial behavior. Since company foundation involves uncertainty, potential entrepreneurs are known to fear creating a new company. Entrepreneurship has been confirmed in advanced studies to not only reduce this fear but also positively influence one's entrepreneurial intention. This study presents a research model that connects entrepreneurship, entrepreneurial intention, and entrepreneurial behavior and verifies it via empirical analysis. It was confirmed as a result that entrepreneurial intention is positively influenced by actively engaging with changes of a certain product or service, problem-solving capability, resolving unexpected setbacks during company foundation, and expertise in the business field where the founded company belongs to. It was also confirmed that entrepreneurial intention has a positive influence on entrepreneurial behavior. In the conclusion of this study, importance and necessity of entrepreneurship education are discussed in order to essentially improve entrepreneurial intention and company foundation via entrepreneurship education.

• The Journal of the Korea Contents Association
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• v.13 no.5
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• pp.234-242
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• 2013

In 2007, Long-Term Care Insurance Law was enacted to share the family burden of caring for the elderly who are unable to perform every day living activities due to their old age and chronic diseases such as senile dementia, diabetes mellitus, stroke and more. Backed by this law, since 2008, care workers have been sent to the elderly care centers or each elder's home to help them not only with their recovery from illnesses, but also with general activities from dressing, eating, bathing, walking even to toileting. However, according to the recently released survey by National Human Rights Commission, it has been found that the caring workers are in a very poor working condition including low income, abused blanket wage system, shortage of welfare services, extra works and even sexual harrassment. It is becoming an important issue due to fast-ageing population, the fact that the care workers have had experiences of violation in their right of labor while they are at work needs to be carefully treated. In that sense, this article presents some difficulties the caring workers face and proposes effective ways to solve these problems through the perspective of human rights and human labor rights based on the report written by National Human Rights Commission. In short, for this law to function properly and to boost the worker's capability of providing better services to beneficiaries, followings can be good answers - enhanced management and supervision on caring plans and care centers, providing immediate counselling and protection for victimized care givers, training courses offered to promote service receiver's sincere respect and strengthened awareness upon care givers.

• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.121-129
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• 2012

Any development plan of a Korean space-based navigational system has been neither designed nor introduced yet. However, the demand for the development of a domestic regional satellite navigation system can be originated from the outside of market. The growing dependency on satellite navigational systems in Korea eventually requires the retainment and the operation of a domestic navigational satellite system. There is not many choices on the orbit designs and the system design concepts of a regional augmented navigation satellite system or a regional navigation satellite system for the service on the vicinity of the Korean peninsular. Space situational awareness (SSA) has been a rising issue for both national security and more realistic space business in Korea. Also SSA related technologies in Korea is a newly inaugurated area and is necessary to generate a navigation messages and maintain a future Korean navigation satellite system. In this study, the availability of Japanese Quasi Zenith Satellite System (QZSS) expected to be deployed definitely sooner than Korean counter-part is analyzed. The availability of the similar configured system over Korea is investigated with assumed QZSS type orbit. Also, feasible configuration of orbits for domestic navigation satellite system is suggested. And the observability of a ground-based optical tracking system as a secondary tracking capability is analyzed.

• Journal of Korea Technology Innovation Society
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• v.15 no.3
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• pp.649-674
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• 2012

The purpose of this study is to investigate the effects of public R&D subsidies on private R&D. We have analyzed rationales for the public R&D subsidy from different perspectives. On the basis of literature review, a two step research model is constructed: participation phase (when firms benefit from public subsidies) and decision phase (when firms make decision on additional R&D investments). Using propensity score matching(PSM) method, we compare the potential outcome of the treated group to a matched controlled group of non-subsidized firms. The data used in this paper was collected from various sources. The Korean Innovation Survey 2008(manufacturing sector) is a main source of data. Financial data such as revenue, asset and capital stock, and number of employees were supplemented from the Nice Information Service KIS Value database. The R&D survey, conducted by MEST(Ministry of Education, Science and Technology) each year, was also used for the R&D expenditures of the manufacturing firms. This study comes up with the following empirical results. First, a firm's innovation capability, financial constraints, and sector appear to influence the selection of firms who were benefited from government's financial supports for R&D. Second, empirical results show that public R&D funding complements private investment on average and appear to have perpetual effects on the following year. Finally, sectoral difference in the effect of public subsidies on firms' R&D investment was confirmed. In addition, SMEs show more positive effects than large firms.

• Journal of Convergence for Information Technology
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• v.10 no.10
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• pp.183-195
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• 2020

In this study, the objective of this study is to verify the effects between lecturer's capability, education program, education service, and physical educational environment factors, and university students' interest in and attitude toward mathematics. A survey was conducted on 228 male and female students in science and engineering majors attending universities in the Pusan metropolitan area, and empirical analysis was conducted using the SPSS 26.0 program. The research results are as follows. First, among the characteristics of college mathematics maker classes, instructor competency (β=.349, t=6.380, p<.001), educational program (β=.361, t=5.650, p<.001), and physical educational environment (β=.196, t=3.281, p<.01) had a significant positive (+) effect on college students' interest in mathematics. Second, the factors of interest (β=.349, t=6.380, p<.001) in college mathematics maker classes were found to have a significant positive (+) effect on college students' attitudes toward mathematics. Third, among the characteristics of college mathematics maker classes, instructor competency (β=.340, t=6.365, p<.001), educational program (β=.352, t=5.559, p<.001), physical educational environment (β=.226, t=3.537, p<.01) was found to have a significant positive (+) effect on college students' attitudes toward mathematics. Through the results of this study, it was concluded that when the level of education program and teaching ability of the university mathematics maker class are high and the physical educational environment is excellent, it can have a positive effect not only on the university student's attitude towards mathematics but ultimately on the attitude of mathematics.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.1
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• pp.32-39
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• 2015

The voice communications with wireless backbone based networks are evolving into a packet switching VoIP systems. In those networks, a call processing scheme is required for management of subscribers and connection between them. A VoIP service scheme for those systems requires reliable subscriber management and connection establishment schemes, but the conventional call processing schemes based on the centralized server has lack of reliability. Thus, the mutual-backup architecture of SIP-servers is required to ensure efficient subscriber management and reliable VoIP call processing capability, and the synchronization and call processing schemes should be changed as the architecture is changed. In this paper, a mutual-backup architecture of SIP-servers is proposed for wireless backbone based networks. A message format for synchronization and information exchange between SIP servers is also proposed in the paper. This paper also proposes a FSM scheme for the fast call processing in unreliable networks to detect multiple servers at a time. The performance analysis results show that the mutual backup server architecture increases the call processing success rates than conventional centralized server architecture. Also, the FSM scheme provides the smaller call processing times than conventional SIP, and the time is not increased although the number of SIP servers in the networks is increased.

• Journal of Internet Computing and Services
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• v.18 no.4
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• pp.121-131
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• 2017

With emergence of Internet, social media, and mobile service, the consumers have actively presented their opinions and sentiment, and then it is spreading out real time as well. The user-generated text data on the Internet and social media is not only the communication text among the users but also the valuable resource to be analyzed for knowing the users' intent and sentiment. In special, economic participants have strongly asked that the social big data and its' analytics supports to recognize and forecast the economic trend in future. In this regard, the governments and the businesses are trying to apply the social big data into making the social and economic solutions. Therefore, this study aims to reveal the capability of social big data analysis for the economic use. The research proposed a social big data analysis model and an online consumer sentiment index. To test the model and index, the researchers developed an economic survey ontology, defined a sentiment dictionary for sentiment analysis, conducted classification and sentiment analysis, and calculated the online consumer sentiment index. In addition, the online consumer sentiment index was compared and validated with the composite consumer survey index of the Bank of Korea.

• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.266-278
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• 2012

The objective of this study was developing dynamic stand growth model to predict diameter at breast height (DBH) growth by thinning intensity and cycle for major tree species of South Korea. The yield table, one of static stand growth models, constructed by Korea Forest Service was employed to prepare dynamic stand growth models for 8 tree species. In the process of model development, the thinning type was designated to thinning from below and equations for predicting the DBH change after thinning by different intensities was generated. In addition, stand density (N/ha), age and site index were adopted as explanatory variables for DBH prediction model. Thereafter, using the model, DBH growth under various silvicuture through integrating such equations considering thinning intensities, and cycles. The dynamic stand growth model of DBH developed in this study can provide understanding of effectiveness in forest growth and growing stock when thinning practice is performed in forest. Furthermore, results of this study is also applicable to quantitatively assess the carbon storage sequestration capability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4A
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• pp.352-360
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• 2008

Recently Task Group (TG) 4 of the Institute of Electrical and Electronics Engineers (IEEE) 802.15a has been recommended a system with ranging capability in existence of multiple Simultaneous operating piconets (SOPs) as well as low-cost, low-power. According to the ranging service, coherent and non-coherent based ranging schemes using ternary code have been adopted as a standard. However it is hard to estimate an accurate time of arrival (TOA) in case of using direct sequence based TOA estimation method because pulse repetition interval (PRI) offered by TG is more limited than the maximum excess delay (MED) of channel. To mitigate inter pulse interference (IPI) problem, this paper proposes a non-coherent TOA estimation scheme using non-periodic transmission (NPT) pattern. The proposed receiver is based on a non-coherent energy detection considering with motivation of low rate wireless personal area network (LR-WPAN). TOA information is estimated via proper comparison with a prescribed threshold after the sliding correlation and search back window (SBW) process for reducing TOA error. To verify the performance of proposed ranging scheme, two distinct channel models approved by IEEE 802.15.4a TG are considered. According to the simulation results, we could conclude that the proposed scheme have performed better performance than the conventional method on the existence of multiple SOPs.