• Journal of information and communication convergence engineering
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• v.10 no.2
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• pp.97-102
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• 2012

The differential global positioning system (DGPS) transmits a GPS enhancement signal using a top-loaded monopole antenna in the medium frequency range. The top-loaded antenna in the medium frequency band can attain a radiation efficiency on the order of 10%. The antenna ground plane characteristics affect the antenna radiation efficiency. To improve the radiation efficiency, it is necessary to install the antenna on a ground plane with large enough physical dimensions and good conductivity. The antenna radiation efficiency is a primary factor in determining the DGPS service area. The service area of the DGPS using a medium frequency band is dominantly affected by the antenna radiation efficiency. To determine antenna radiation efficiencies accurately, the antenna radiation efficiencies of DGPS are deduced from the propagation power in this paper. Based on the deduced antenna radiation efficiencies, the service area for the Korean nationwide-DGPS is analyzed and evaluated.

• Journal of Korea Port Economic Association
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• v.27 no.1
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• pp.213-234
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• 2011

The literature on efficiency of the maritime and shipping industry has typically focused on container ports and terminals. The study presented in this paper uses data envelopment analysis to evaluate ocean carriers based on financial and operational data from 2004 to 2007. A comparison is made up of the efficiency of global ocean carriers in efficiency of financial and operational performance respectively. A positive correlation is shown between the input and output data. In the static-efficiency analysis, we describe CCR, BCC and scale efficiency of Global Ocean Carriers in 2007. And we also provide about the stability and trend of their efficiency for four years (2004-2007) in the dynamic-efficiency analysis. The empirical results validate the necessity of restoring freight rates to facilitate the efficiency of the global ocean carriers supported by adjust of the supply of containership space. The study provides a basis for estimating the competitiveness of international shipping companies, for benchmarking best practice and for identifying the specific factors and causes of inefficiency.

• Journal of Distribution Science
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• v.20 no.2
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• pp.31-41
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• 2022

Purpose: Developing and nurturing supply chain dynamic capability is one of the leading solutions to create competitive advantages, maintain growth and sustainable development for businesses. The study was conducted to experimentally confirm the impact of supply chain dynamic capability on competitiveness and business efficiency for Vietnamese wood enterprises. Research design, data and methodology: The study surveyed 236 managers of Vietnamese wood manufacturing and distribution enterprises. The authors applied the structural equation modeling (SEM) to analyze the relationship between the dynamic capability of the supply chain and the competitiveness, business efficiency of enterprises to achieve those goals. Results: The results show that businesses owning supply chain dynamic capability will have better competitiveness and business efficiency. Especially, in the context of Vietnamese wood sector, the larger the scale of business, the more profound the impact of supply chain dynamic capability on competitiveness and business efficiency. Conclusions: Focusing on developing supply chain dynamics would be a promising solution to improve the competitiveness of Vietnam's wood enterprises in the global market.

• Journal of the Korean Society of Safety
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• v.30 no.6
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• pp.132-138
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• 2015

This study examined the relative effects of feedback frequency and specificity of Eco-IVIS(eco in-vehicle information system) on the fuel-efficiency and workload. Eighty participants randomly assigned into four experimental groups (high frequency/specific, high frequency/global, low frequency/specific, and low frequency/global feedback) and they drove 16.4Km motorway under the each feedback condition. The dependent variable were fuel efficiency and Drive Activity Load Index which measured participants' subjective ratings of driving workload. The results showed that high frequent feedback was more effective for increasing fuel-efficiency than low frequent feedback, however, there was no significant difference of fuel-efficiency between specific and global feedback. Although, overall DALI score was comparable among four experimental conditions, visual demand score was significant higher under the high frequent feedback condition than low frequent feedback.

• Health Policy and Management
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• v.25 no.2
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• pp.118-128
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• 2015

Background: We measured productivity changes of regional public hospitals using both global Malmquist productivity index-based on global production possibility set over all the periods-and the traditional Malmquist productivity index and analyzed the factors of productivity change. Methods: The data used in this study is two annual inputs and two annual outputs of 32 regional public hospitals in Korea from 2005 to 2009 and the results such as distances and Malmquist productivity index and global Malmquist productivity index are obtained by an R program written for this study. Results: The results can be summarized as follows. Firstly, technical efficiencies of regional public hospitals are affected largely by scale efficiency than pure technical efficiency. Second, productivity progressed and technological change has more significant influence on productivity advance over the period between 2005 and 2009. Third, the circularity problem of the traditional Malmquist index is confirmed, and so the global Malmquist index without this problem are valid for the analysis. Conclusion: Though this study also has some limitations with the data of regional public hospitals with a short time span, it is the first study of hospitals using global Malmquist productivity index and later it can be expanded to private hospitals and longer time periods.

• Animal Bioscience
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• v.37 no.4_spc
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• pp.719-729
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• 2024

Global pig production has increased by 140% since the 1960s. The increase in global population, coupled with improving socioeconomic conditions of many countries has led to an increased consumption of meat globally, including pork. To keep up with demand and capitalize on economic opportunities, the countries of China, the United States (US), and the European Union (EU) have become the top 3 pork producers globally. China is of particular interest, as it is the both the largest country in pork production and pig numbers, as well as being the largest importer of pork from other countries. Globally, the efficiency of pork production has improved, in relation to the integration of pig production and the dramatic increase in research efforts in pig nutrition and production. Through integration, large producers can consolidate resources and maximize profits and efficiency. The increased research interest and efforts in pig production have given scientists and producers the opportunity to collaborate to adapt to challenges and identify possible solutions to issues brought on by a volatile global market. Intestinal health (23%), general nutrition and growth (23%), and amino acid nutrition (15%) were the top 3 areas (61%) leading research trends in pig nutrition and production. Major dietary interventions with feed additives evaluated include functional amino acids, feed enzymes, pre-/pro-/post-biotics, and phytobiotics with a common goal to improve the growth efficiency by enhancing nutrient utilization and intestinal health. With increasing global issues with environment, pig producers and the supporting scientists should continue their efforts to improve the production efficiency and to reduce the environmental footprint from pig production.

• Management & Information Systems Review
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• v.27
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• pp.149-172
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• 2008

Since the 9/11 terror attack, the event which caused supply chain disruption, supply chain security has becomes more important than ever before. Furthermore, such company's logistics strategies conflicting supply chain security as increased global sourcing, JIT manufacturing are increasing supply chain vulnerability. It could burden for global companies to strengthen supply chain security because not only it requires additional investment cost but also changes of companiy's global logistics strategy. However, on the other hand, supply chain visibility and resilience can be improved through supply chain security. In addition, it allows companies to stabilize supply chain structure as well as rapid and flexible response to market demand. The key issue is balancing between efficiency and supply chain security. To do this, identifying risk elements under the supply chain and assessing vulnerability of each supply chain components should be performed before developing efficient supply chain security management system without obstructing supply chain efficiency.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.10
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• pp.1298-1302
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• 2018

Minimum Efficiency Performance Standard (MEPS) has already been operated in many countries. In particular, the European Union (EU) has entered the IE3 stage since 2017. Korea will also enter the IE3 phase from October 2018. As for Korea, there is still a restriction on induction motors only. But, in the EU and the United States, efficiency regulation of variable speed drives is being deeply examined. Standards related to this are gradually being fixed. In this paper, the current status and the direction of global standards related to the efficiency of motors, inverters and systems are reviewed. And the case of improving the efficiency of the system including the motor will be examined.

• Journal of Korean Society of Transportation
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• v.26 no.5
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• pp.41-49
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• 2008

According to the demand for services. a single point contract between a user and provider spreads over the industry, and the relationship between them is a main issue. The user wants to make a deal with the contributor which can provide the effective services to the user. This study is to estimate the efficiency of global logistics industry with Data Envelopment Analysis, by nations from 2001 to 2005. Furthermore, it tries to estimate the inefficiency affected by macro factors, and proves the association between them using Tobit model. Global logistics industry has made growth both externally and internally more than doubled for the last 5years. Technical inefficiency of global logistics industry is more influenced by pure technical inefficiency than inefficiency of scale. Therefore technical efficiency can be increased by decreasing pure technical inefficiency. Through this study, it found that the logistics industry got influenced to its efficiency by high price of oil, and courier and transportation service market is formed stably. Furthermore, it advocates policy planners to consider effectiveness and clearness of policy which influence to inefficiency of logistics industry. Also, it found that labor and financial support can give critical effect.

• Journal of Broadcast Engineering
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• v.22 no.3
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• pp.397-400
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• 2017

Recently, a lot of images containing various global movements have been generated by the activation of the photographic equipment such as the drone and the action cam. In this case, when the motion such as rotation, scaling is generated, it is difficult to expect a high coding efficiency in the conventional inter-picture prediction method using the 2D motion vector. In this paper, we propose a video coding method that reflects global motion through homography reference pictures. As a proposed method, there are 1) a method of generating a new reference picture by grasping a global motion relation between a current picture and a reference picture by homography, and 2) a method of utilizing a homography reference picture for inter-picture prediction. The experiment was applied to the HEVC reference software HM 14.0, and the experimental result showed an increase in encoding efficiency of 6.6% based on RA. Especially, the results using the videos with rotational motion have a maximum coding efficiency of 32.6%, which is expected to show high efficiency in video, which is often represented by complex global motion such as drones.