• Journal of Technology Innovation
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• v.13 no.2
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• pp.207-222
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• 2005

A prerequisite for making R&D more productive is to able to measure its productivity. Most of the previous studies on this topic have attempted to measure R&D productivity at the firm or industry levels. In this study, however, R&D productivity is measured at the national level to provide R&D policy implications, particularly for Asian countries. Contrary to the previous studies where total factor productivity was adopted, this study employs the data envelopment analysis (DEA) approach to measure R&D productivity. DEA is a multi-factor productivity analysis model for measuring the relative efficiency of each Decision Making Unit (DMU). In addition to the basic DEA model that includes all inputs and outputs, five additional models are constructed by combining single input with all outputs and single output with all inputs in order to measure specialized R&D efficiency. In this study, the twenty-seven countries are classified into four clusters based on the output-specialized R&D efficiency: inventors, merchandisers, academicians, and duds. Then, the characteristics of the Asian countries with respect to R&D efficiency are identified. It is found that Singapore ranks high in total efficiency, and Japan in patent-oriented efficiency. Meanwhile, China, Korea, and Taiwan are found to be relatively inefficient in R&D. We expect that the findings from this study will be able to provide directions for R&D policy-making of the Asian countries.

• The KIPS Transactions:PartC
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• v.12C no.1 s.97
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• pp.1-10
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• 2005

Electronic Data Interchange(EDI) between a number of companies goes on increasing on the internet. Although a conventional EDI system reduces business process efforts, time, resources, etc., important information is easily and frequently exposed by well trained hackers and crackers, which inflict a severe loss on the company and even put the company under a crisis. This study integrates the conventional EDI system and Virtual Private Tet(VPN) to maximize an overall efficiency of speed and security in data transferring by the level of importance. The EDI system interfaced to IPSec and L2TP of VPN allows us to select two modes : the one focuses on a high speed with a low or a medium level security or the other does on a high level security with a low or a medium level speed. Both the company and the end users get a lot of tangible and intangible advantages by integrating the EDI system and VPN.

• Journal of Advanced Navigation Technology
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• v.18 no.1
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• pp.67-73
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• 2014

Due to the development of the communication technology and the high-performance mobile device, the number of video streaming service user has been increasing. Video streaming services in the restricted network environments need error control to support users for the Ultra High Definition(UHD) video delivery. Packet-level FEC method was used to control the error for delay-sensitive video service, but it has a defect in huge occupation of network resources by redundant packets. In this paper, we proposed a packet-level FEC algorithm which maintains the video quality by previous FEC methods and also reduces the occupation of network resource in the restricted network environments. The proposed algorithm controls the redundant rate with using the delivery characteristic of the video coding technology, and improves the efficiency of network resources by reducing the traffic by around 33% in comparison with the previous FEC methods.

• Fire Science and Engineering
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• v.25 no.1
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• pp.1-6
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• 2011

An evacuation simulation was carried out to confirm evacuation efficiency for stair width and problems in calculation of occupant load for high-rise buildings. The evacuation time and number of evacuated persons from a 39 story condominium-mercantile building were calculated by using Simulex for stair widths of 1.2 m, 1.5 m, and 1.8 m. The total occupant load based on the Korean code was higher than the number of actual residents by 2.3 times, and that based on the NFPA 101 Life Safety Code by 2.6 times, respectively. For the occupant load based on the Korean code, smaller stair width resulted in lower evacuation efficiencies due to bottlenecks in egress. For the actual residents and NFPA code-based occupant load, a high evacuation efficiency and negligible effects of the stair width on evacuation efficiency were confirmed. It was shown that there was a bottleneck even at the stair width of 1.8 m for the Korean code-based occupants, while the stair width of 1.2 m provided safe egress to the actual residents or NFPA code-based occupants. This recommended further studies on possibility of lowering the level of the Korean code in calculation of the occupant load.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.145-148
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• 2002

This paper has been studied a predistorter which is able to linierizing of RF amplifier using schottkey. If input signal level is low, input signal is delivered directly. And if input signal level is high, input signal Is delivered with decreasing. So RF amplifier always works at saturation region .When this predistorter is used to simplified C-class RF amplifier, we have concluded that efficiency is improved about 3%.

• International Journal of Advanced Culture Technology
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• v.8 no.4
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• pp.8-17
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• 2020

This study aims to draw up comprehensive ethical management practices so that companies can be reborn as high-quality companies not only at the level of management efficiency but also at the level of corporate integrity. -The main focus of in this study is as follows: To curb corrupt practices in the corporate sector, it is necessary to strengthen the monitoring function and accountability system of audits (internal audits, full-time audits, audit committees, external audits). In order for these system improvements to be made reliably, it is necessary to periodically measure and evaluate employee satisfaction with the overall personnel system.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.2
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• pp.191-202
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• 1998

An electronic-hydraulic controlled line pressure system was suggested based on the mechanical controlled CVT base model. As a high level control strategy, a 3-D optimal line pressure map was obtained considering the driver's desire, driving conditions. Also, PID type low level controller was designed. Using the high level control strategy and the dynamic models of the base model CVT with electronic controlled line pressure system, performance simulations were carried out. It is seen from the simulation results that fuel economy of the electronic controlled strategy keeps the line pressure low, which results in the improved efficiency of the hydraulic system.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.173-176
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• 2006

This paper discusses the ZVS/ ZVZCS Three-Level converter using the minimum auxiliary circuit. A primary auxiliary circuit, which consists of one coupled inductor is added in the primary circuit to provide ZVZCS conditions to primary switches. ZVS is for outer switches and ZCS or ZVS is for inner switches. Many advantages including simple circuit topology high efficiency, and low cost make this converter attractive for high power applications. The principle of operation, feature and design considerations arc illustrated and verified through the experiment with a 2kHz 400kHz IGBT based experimental circuit.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.562-564
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• 2008

This paper deals with the three phase high voltage power-grid connection topology using multi-level inverter. Due to the multi-level inverter, these are improved effect of fluctuating voltage, problem of EMC and switching loss using suitable switching patterns of device, above all thing, it is easy to realize the system because of using lower voltage rating switch. This topology can be applicable to power-grid connection of wind system, there is a good point about economical efficiency. The simulation results are presented to verify the validity of the proposed topology.

• Vacuum Magazine
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• v.2 no.2
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• pp.12-16
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• 2015

Organic photovoltaics (OPVs) have attracted significant interest in an interdisciplinary research field for the decades as a next-generation photovoltaic device due to their unique advantages. One of requirements for OPVs having high power conversion efficiency is the favorable energy level alignment between the electrode/organic and organic/organic interfaces to manage the exciton dissociation and improve the charge transport. In this review, strategies to enhance the OPV performance by controlling the energy level alignment are discussed. The insertion of an exciton blocking layer leads to the efficient dissociation of photogenerated excitons at the donor/acceptor interface enhancing the short-circuit current density. The choice of a donor having a high ionization energy and an acceptor having a low electron affinity increases the open-circuit voltage. The insertion of an appropriate work function modifier which reduces the charge injection barrier removes the S-kink in current density-voltage characteristics of OPVs and improves the fill factor. This review would give a valuable guide to design the efficient OPV structure.