• Journal of Information Technology Applications and Management
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• v.22 no.1
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• pp.153-163
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• 2015

The purpose of this study is to investigate the relationship among factors that expand the win-win growth between domestic finished goods-making manufacturers and subcontractors. One-hundred twenty six firms participated for this study and were used for the data analysis. As a result of analysis, first, it was found that the win-win growth between first-tier suppliers and second-tier suppliers has positive effects on the win-win growth made by second-tier suppliers helping the third-tier suppliers. Second, it was found that the win-win growth policies supported by the government for the positive relationship between first-tier suppliers and second-tier suppliers for the finished goods-making manufacturers have positive effects on the win-win growth between second-tier suppliers and third-tier suppliers. Third, the results also showed that the win-win growth between second-tier suppliers and third-tier suppliers has a positive influence both on the financial and on the non-financial performances of the second-tier suppliers. Based on the results of this study, it is recommended to (1) construct infrastructure by sector through partnership between finished goods-making manufacturers and subcontractors, (2) draw in active support through the governmental win-win growth policies, (3) induce increasing productivities through information sharing, manpower support, technical support and educational support, and (4) strengthen and cultivate the culture of the small- and medium-sized companies.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.12 no.2
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• pp.125-136
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• 2017

This study focuses on a relative efficiency of 109 operating food companies out of 22 regions in Jeollanam-do. The relative efficiency has been analyzed by 5 input factors(capital, number of employees, annual labor costs, raw material purchase, and site area) and 2 output factors(annual exports and annual production of the companies in Jeollanam-do). This study suggests efficient companies which inefficient companies can benchmark to improve their system in short-mid-long term in phases. The main result of empirical analysis are as follows: Firstly, according to the Traditioanl DEA analysis, 7 companies out of 109 DMU indicate the optimal production scale in score 1 of CCR efficiency value, BCC efficiency value, and scale efficiency value. Secondly, a result from the Tier 1 step of inefficient companies by Post-DEA suggests that it would be better to apply each Tier step to the proper stage of the worst 5 inefficient companies such as Tier 3 step(short-term benchmark)${\rightarrow}$Tier 2 step(mid-term benchmark)${\rightarrow}$Tier 1 step(long-term benchmark) in step. This study expects that the result of the study can reduce the trial and error in inefficient part, lead to improvement, and have a big help in food exporting industry in the end.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2010.04a
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• pp.209-210
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• 2010

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.5
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• pp.275-284
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• 2014

This paper considers two-tier networks consisting of macrocells and femtocells operating in the same spectrum. This paper proposes a femtocell spectrum reuse scheme that determines the shared spectrum and transmit power for the femtocells to mitigate the effects of cross-tier interference between the macrocells and femtocells. The proposed scheme provides macrocell throughput that is unaffected by the increasing number of femtocells per cell site and improves the femtocell signal quality at the same time by limiting the cross-tier interference. This study analyzed the per-tier signal-to-interference ratio (SIR) and outage probability of the proposed scheme to investigate the macrocell and femtocell performance. The total throughput of the proposed scheme was analyzed based on the outage probabilities. The analysis and numerical results proved that high femtocell throughput can be achieved using only a small fraction of the spectrum while protecting the macrocell throughput. As a result, an improved total throughput was achieved enforcing higher spatial reuse.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1481-1500
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• 2016

Device-to-Device (D2D) communication underlaying macro-small cell networks, as one of the promising technologies in the era of 5G, is able to improve spectral efficiency and increase system capacity. In this paper, we model the cross- and co-tier D2D communications in two-tier macro-small cell networks. To avoid the complicated interference for cross-tier D2D, we propose a mode selection scheme with a dedicated resource sharing strategy. For co-tier D2D, we formulate a joint optimization problem of power control and resource reuse with the aim of maximizing the overall outage capacity. To solve this non-convex optimization problem, we devise a heuristic algorithm to obtain a suboptimal solution and reduce the computational complexity. System-level simulations demonstrate the effectiveness of the proposed method, which can provide enhanced system performance and guarantee the quality-of-service (QoS) of all devices in two-tier macro-small cell networks. In addition, our study reveals the high potential of introducing cross- and co-tier D2D in small cell networks: i) cross-tier D2D obtains better performance at low and medium small cell densities than co-tier D2D, and ii) co-tier D2D achieves a steady performance improvement with the increase of small cell density.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1315-1319
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• 2011

As government's policy is enacted to reduce greenhouse gas emission in transportation sector, railroad sector has to estimate amount of emission and propose feasible methods to reduce emission. To calculate accurate emission of railroad sector, we performed a study on the calculation model development for Tier 3 GHG emission factors. According to IPCC guide line, Tier 3 emission factor reflects individual characteristic of diesel locomotive. For this reason, we estimated GHG emission factor by stratified diesel locomotive and the result show difference of emission factor by notch changing. Therefore, the analysis of notch frequency during operation is required to develop Tier 3 emission factor, and we analysed a running pattern of diesel locomotive. As a result, idle and 8 notch consist about 70% of total running distance. In conclusion, the calculation model suppose that Tier 3 GHG emission factor is the sum of multiplied emission factor by weights in each notch. This result can contribute to Tier 3 emission factor calculation and reduction method development of emission in railroad sector by managing driving efficiency and technology development.

• Journal of Korea Port Economic Association
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• v.25 no.1
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• pp.15-28
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• 2009

The purpose of this paper is to show the empirical extraction way of benchmarking ports for overcoming the shortcoming which the traditional DEA method has by using 20 Korean ports in 2003 for 2 inputs (birthing capacity, cargo handling capacity) and 2 outputs(Export and Import Quantity, Number of Ship Calls). Because DEA method has produced the limited set of efficient units which are reference to inefficient units respective of their differences in efficiency scores, it is necessary to adopt the more feasible benchmarking information according to the path analysis(tier or stratification). The core empirical results of this paper are as follows. Benchmarking ports against inefficient ports according to the tier analysis are that Masan Port(Janghang$\rightarrow$Jeju$\rightarrow$Seogoipo$\rightarrow$Yeosu), Jinhae Port(Janghang$\rightarrow$Mogpo$\rightarrow$Seogoipo$\rightarrow$Wando), Pohang&DonghaePort(Janghang$\rightarrow$Samcheonpo$\rightarrow$Pyungtag$\rightarrow$Samcheog), and Sogcho Port(Janghang$\rightarrow$Mogpo$\rightarrow$Seogoipo$\rightarrow$Wando). The policy implication to the Korean seaports and planners is that Korean seaports should introduce the new methods like Tier analysis of this paper for evaluating the port performance and enhancing the efficiency in short term, mid term, and long term according to the tier 3 stage, the tier 2 stage, and the tier 1 stage with original DEA stage.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.5
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• pp.590-597
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• 2013

For a lower tier defense, the distance between a launcher and an engagement control station is quite important to estimate the proper defense area and to effectively arrange missile launchers. In this paper, we have analyzed an effectiveness of anti-ballistic missile launcher arrangement for the lower tier defense against the ballistic missile. The operation concept, specific configuration and aerodynamic characteristics of the ballistic missile such as SCUD-B/C, Nodong are considered in order to develop a realistic engagement simulation. The diverse engagement results through numerical simulations are provided to conduct the effectiveness analysis of anti-ballistic missiles.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.3
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• pp.231-245
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• 2002

A better knowledge of emission inventories can serve several important functions such as provision of public information, identification of primary sources, assessment of temporal and spatial trend, and analysis for national modelling studies. The purpose of this paper is to propose the new air emission source categories on the basis of the Korea Standard Industrial Classification. Hence, the paper focuses on reviewing and comparing the air emission sources categories of USEPA, and EU. The new emission source categories compose Tiers 1, 2, and 3. For Tier 1, there are 14 categories; fuel combustion-utilities, industries, and heating and others, chemical and allied product manufacturing, metals processing, and petroleum and related industries, etc. Tier 2 consists of small categories classified minutely in Tier 1. Tier 3 connects the categories of Tier 2 with the Korea Standard Industrial Classification.

• Journal of Climate Change Research
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• v.5 no.1
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• pp.61-70
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• 2014

The amount of greenhouse gas (GHG) emissions has been increasing steadily over the last 3 years (2009~2011), averaging 5.7 percent a year, due to the growth of low cost carriers and the increased demand for air transportations. The present study attempts to investigate the aviation fuel consumption and GHG emissions of Tier 3a type by the flight phase from three aircraft type such as B737-600(routes between Gimpo-Jeju airport), B737-700(routes between Gimpo-Jeju airport and Inchon-Narita), B737-800(routes between Inchon-Narita) using the Flight Operation Quality Assurance(FOQA) data of the year 2011.