• Journal of Navigation and Port Research
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• v.37 no.2
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• pp.195-201
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• 2013

Recently according to increase of enlarged scale ports in conformity with increase in over size vessels and container handling service, pollutants generated from ports are increasing. In advanced countries, reduction in carbon dioxide emission assigned to them has been implemented according to the Climate Change Convention and Kyoto Protocol from 2008 to 2012 in order to lessen carbon dioxide emission. Henceforth increase in discussion on the measure of constructing Green Port and low-carbon port is expected in our nation's field of port as well, it is considered that the effort in reduction with regard to undesirable output which causes environmental problem of analysis target during measuring effectiveness. Therefore, in this study, effectiveness was estimated through directional technology distance function considering undesirable output differently from effectiveness analysis of existing container terminal, and then performed comparative analysis with the result analyzed with BCC output-oriented model. As the result of analysis, in 2007 DMU3 and DMU5, and in 2010 DMU2 and DMU4 appeared to be efficient terminals in BCC output oriented model, and in directional technology distance function model, DMU1, DMU3 in 2007, DMU3, DMU5 in 2008, DMU7 in 2009, and DMU2, DMU5 in 2010 appeared to be efficient terminals.

• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.43-43
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• 2018

• Environmental and Resource Economics Review
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• v.16 no.1
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• pp.171-197
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• 2007

In this paper we provide a methodology that permits test of feasibility of Porter hypothesis under limited data environment by utilizing two types of output distance function: Shephard distance function and directional distance function. The production technology supported by Porter hypothesis is embodied in the directional distance function. The average annual marginal abatement cost for $SO_2$ obtained by estimating the directional distance function is higher than the one obtained with the Shephard distance function by about 50 percent in the Korean electric power industry over the period 1970~1998. This result implies that feasibility of Porter hypothesis depends upon whether investment in production capital and process can bring more than a 50 percent increase in the average productivity.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.26 no.4
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• pp.27-35
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• 2018

Recently, Intense competition is expected to bring about continuous change with the rapid global aviation industry. In particular, domestic passenger demand has been steadily increasing over the past five years, with domestic and international shipments growing at a CAGR of 8.4% and 10.0%, respectively. In addition to the economic value of the airport, social interest due to greenhouse gas emissions is also rising. In this study, we analyzed the efficiency of airport operation by using DEA model(Directional Technology Distance Function) considering undesirable output for 14 airports in Korea. As a result of analysis, all airports except Gimhae, Yangyang, Cheongju and Yeosu were analyzed as efficient airports. However, only Gimpo, Gimhae, Jeju, Muan, Daegu and Gwangju were analyzed as efficient airports considering the undesirable output.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.6
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• pp.668-672
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• 2005

In this paper, a distance measuring system using a PSD sensor in proposed, which in suitable for low-cost localization sensor of a mobile robot. Because the distance-voltage output of PSD sensor has a non-linear property, the linearizing function is proposed through the experimental characteristics of the sensor. And the characteristics are tested and the distance-voltage data are measured in various colors and materials of object. The parameters of the proposed function are extracted by using the measured data. Finally, the performance and the accuracy of the developed system are verified according to the comparison of the distance by the proposed function with the real distance.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1427-1430
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• 2005

In this paper, the range finder system using a PSD sensor suitable for low-cost localization sensor of a mobile robot. Because the distance-voltage output of a PSD sensor has a non-linear property, the linearizing function is proposed through the experimental characteristics of the sensor. And the characteristics are tested and the distance-voltage data are measured in various colors and materials of object. For a known environment, a mobile robot scans the surroundings using a PSD sensor that can rotate $360^{\circ}$. Finally, the performance and accuracy of the developed system are verified according to the comparison the distance by proposed function with real distance

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.2
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• pp.81-94
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• 2012

On December 11, 2001, China joined the WTO and became one of the member countries and the Chinese financial markets had to be open in 5 years. So, the Chinese government transformed national commercial banks into joint-stock banks. The purpose of this paper is to investigate the validity of this decision by the Chinese government. In order to measure the efficiency of banks, the directional distance function (DDF) methodology is used, which analyzes whether a bad output exists in the outputs. In the empirical analysis, the number of staffs, the fixed assets, and the equity capital are used as inputs, while the loans and the non-performing loans ratio are used as a good output and a bad output, respectively. The non-performing loans ratio is included in output since it could affect the efficiency of banks. If it isn't considered in the analysis, a distortion might occur in analyzing the efficiency of banks. The results show that the efficiency of the major commercial banks was improved, and that the efficiency of joint-stocks banks was higher for 2002-2003 while the efficiency of national commercial banks was higher for 2004-2006. It was due mainly to the foreign exchanges reserve funds injected into national commercial banks by the Chinese Ministry of Finance, and as a result bad assets were eliminated.

• Journal of Korean Society of Transportation
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• v.24 no.5 s.91
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• pp.45-56
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• 2006

In order to construct an information pool on the production characteristics and efficiency of Korean railroad industry, various alternative approaches have to be applied. In this paper we present an empirical application of the distance function to measure the technical efficiency and the production characteristics of Korean railroad industry, The distance function firstly introduced by Shephard (1953) provides the advantage that it does not need information about prices, so it can accommodate the multiple output nature of the railway only using the quantifies as data. This is of great relevance in the context of the public sector such as railroad industry where there are often distinct control mechanisms on input prices. Also the distance function allows us to obtain a measure of technical efficiency as well as a measure of production characteristics. From annual data on Korean railroad industry during 1964-2004, multiple output distance function is estimated using quadratic programming model. The resulting technical efficiency estimates has tended to be improved over the period $1980{\sim}2004$. The indirect Morishima elasticities of substitution indicate that the substitutabilities for labor are relatively very low or impossible. The average scale elasticity is 2.7 which means that increasing the scale by 1per cent will result in an output increase by 2.7 percent. This result indicates that economies of scale are present in the Korean railroad industry.

• Korean Journal of Optics and Photonics
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• v.21 no.3
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• pp.97-102
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• 2010

A pattern density function using simulation analysis for controlling LGP output distribution was proposed. The pattern density function was found as [Pexp(-y/70)+Qexp(+y/25)]R. We analyzed the LGP output distribution of a hemi-sphere pattern using the function and then found that its output distribution was clearly improved as compared with that of the equi-distance pattern. We found that the density function works well for the pyramid pattern case as well as.

• ETRI Journal
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• v.32 no.1
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• pp.93-101
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• 2010

A true random number generator (TRNG) is widely used to generate secure random numbers for encryption, digital signatures, authentication, and so on in crypto-systems. Since TRNG is vulnerable to environmental changes, a deterministic function is normally used to reduce bias and improve the statistical properties of the TRNG output. In this paper, we propose a linear corrector for secure TRNG. The performance of a linear corrector is bounded by the minimum distance of the corresponding linear error correcting code. However, we show that it is possible to construct a linear corrector overcoming the minimum distance limitation. The proposed linear corrector shows better performance in terms of removing bias in that it can enlarge the acceptable bias range of the raw TRNG output. Moreover, it is possible to efficiently implement this linear corrector using only XOR gates, which must have a suitable hardware size for embedded security systems.