• 한국산학기술학회논문지
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• 제20권9호
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• pp.29-34
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• 2019

본 연구에서는 배출가스 및 연비시험에서 드라이브 품질을 평가하기 위해서 가솔린 시험차량 1대를 선정하여 측정하고, 그 측정결과와 제작사가 제시한 값과 비교하여 허용오차 범위(연비-5%, 온실가스+5%, 이하 "허용오차범위")를 초과하는지 평가하였다. 측정결과의 평균값이 제시한 값과 유효한지 데이터를 분석하였다. 본 연구에서는 SAE J2951 평가방법을 기반으로 시험자간의 주행모드 추종성을 가지고 허용오차범위에 대한 데이터 확보를 위해 시험을 수행하였다. 시험차량은 2L급 가솔린차량을 선정하였다. 검증결과 주행 추종성은 고의적인 주행조건에서 전체 값이 커지고, 부드러운 주행조건 일 때, 값이 줄어드는 것을 확인하였다. 주행 추종성 분석결과 수치가 1에 가까울수록 정확하게 주행한 것이며, (-) 음의방향으로 분포하고 있는 가혹조건과 (+) 양의방향으로 분포하고 있는 완만한 조건이라 할 수 있다. 본 연구에서 수행된 시험의 분석을 시험자간 드라이브 추종성에 대한 기초 데이터를 확보하였고, 이러한 기초 데이터는 연비모드의 목표 속도 허용범위 내에서의 운전추종성에 대한 연비 상관성을 분석하였고, 향후 측정결과는 연비측정 모드별 배출가스 DB 확보 및 연비제도에 중요한 기초 자료로 활용될 것으로 사료된다.

• 한국항만학회지
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• 제3권1호
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• pp.3-33
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• 1989

The amount of the Korean export & import in 1987 reached $88.3 billion which was 1.75% of the total world trade and the proportion of foreign dependence to G.N.P was 74.5%. From these facts, we can infer that the development of national economy is largely dependent upon trade. Therefore the role of transportation, especially Ocean transportation, as a basis of economic development through trade is one of the main factors that can not be passed over. Here, We can define that a port as a subsystem of transportation determines the efficiency of the total transportation system. Thus, the purpose of this paper is to contribute in improvement of the efficiency in port, reinforcement of the international competitiveness for exporting goods by the analysis of the cargo handling charges. In order to do this, this paper deals the case of B.C.T.O.C. Furthermore, this study gives some important informations related to the level of tariffs for establishing an autonomous port administration. The Summary of the conclusions of this paper is as follows ; 1) The object of port administration in Korea has been emphasized on the maximization of efficiency in using the port facilities. Nowadays, however, it should be moved to a direction that port is operated under the compound aims considering the public interests and economy. 2) For a criterian of tariff calculation, A tariff system based on the cost accounting is desirable. In general it is recommended that the cost for construction, management, and operation of port is compensated by the revenue from port operation. Therefore, it is necessary for the administration bodies of each port to establish a tariff system on the basis of the independent profit system. 3) For the investigation of actors of tariff adjustment by the Break-even point analysis, (1) When we conducted the B.E.P analysis using total cost as cost term, we got 3.8% discount in tariff at 12% of target profit rate and 1.5% discount at 15% of rate. when we set the target profit rate as 17% we could have the proper tariff level. (2) When using operating cost as cost term, we got 13.1% discount in tariff at 12% of target profit rate and 10.9% discount at 15% of rate. When setting the target profit rat as 28%, we could have the proper tariff level. 4) Comparing with the tariffs of foreign ports for the basic terminal rate, The tariff level of B.C.T.O.C showed 33% of stevedoring charge and 80% of marshalling charge incurred at Kobe port. The comparison with Singapore port gave 50% of transhipment charge and 17% - 20 % of stevedoring charge. 5) We found that the financial structure of B.C.T.O.C was better than those of other companies and the worth fixed assets ratio was too low. The fact of low worth fixed assets ratio implies that the cargo handling facilities should be increased. Moreover, The return of assets for B.T.T.O.C was good but non-operating expenses were still contained too much in. Therefore, we think that it is necessary for B.C.T.O.C. to rationalize business management. Although the present cargo handing charge for B.C.T.O.C is a proper level in terms of a public corporation, for the final recommendation in connection to the results, It is required to take the rationalization process for business management.

• 국제지역연구
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• 제22권2호
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• pp.61-91
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• 2018

본 연구는 신용보증제도가 효과성 높은 중소기업지원 수단의 하나로서, 그 성과를 업무성격이 다른 국내 공공기관들과 비교하는 것보다 매우 유사한 형태로 운영되고 있는 일본, 대만 신용보증기관과의 글로벌 효율성 비교가 훨씬 유용할 수 있다는 측면에서 3개국 70개 기관의 2016년도 효율성을 DEA모형과 초효율성 모형을 통해 분석하였다. 분석결과, 우리나라 신용보증기관들의 효율성이 일본에 비해 다소 높은 것으로 나타났으며, 효율적으로 운영되고 있는 DMU의 숫자도 비교적 적정한 것으로 분석되었다. 초효율성점수는 히로시마, 대만SMEG, 부산, 지바, 시즈오카, 울산, 기보 순으로 나타났다. 또한, 대부분의 신용보증기관들은 규모수익상태가 체증규모수익상태에 있는 것으로 분석되어 적정수준의 투입 증가전략을 추진하는 것이 효율적일 수 있는 것으로 판단된다. 또한, 우리나라와 일본간 효율성 격차는 통계적으로도 유의한 차이를 보였다. 정책적 시사점으로는 첫째, 일본 신용보증제도의 동향에 대한 주기적 분석이 필요하며, 둘째, 신용보증규모가 국가경제 및 중소기업정책에 미치는 영향을 파악하여야 하고, 셋째, 효율성 결정요인에 관한 분석이 필요하며, 넷째, 비효율의 원인을 고려하여 효율성 개선전략의 방향성을 정립하여야 하고, 다섯째, 다각적인 측면에서 효율성 측정이 이루어질 필요가 있음을 제시하였다.

• 터널과지하공간
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• 제25권6호
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• pp.543-555
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• 2015

최근 대단면 갱도로 개발하고 있는 국내 석회석광산은 작업공간 환기를 위하여 과거 석탄광산에 광범위하게 사용되던 형태의 국부 선풍기를 주로 이용하고 있다. 대단면 갱도에서의 낮은 정압손실을 고려할 때 고풍압 선풍기는 과다 설비용량으로 인하여 비용측면에서 심각한 한계를 보이고 있다. 대단면 갱도에서의 최적 선풍기는 안전한 작업환경 유지를 위한 충분한 환기량을 공급할 수 있어야 할 뿐만 아니라 저운전비용도 보장하여야 한다. 본 연구는 대단면 갱도 내에서 높은 환기효율과 경제성을 가지는 저풍압 국부선풍기를 개발함이 목적이다. 이론적 연구와 아울러 2개소의 단면적이 다른 현장 실험 연구를 통하여 저풍압 선풍기의 환기효율을 분석하였다. 본 연구결과는 작업공간 공기질 및 작업환경 개선을 위한 국부선풍기의 경제성과 효율 제고에 적용 가능할 것으로 기대된다.

• 디지털융복합연구
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• 제3권2호
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• pp.73-116
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• 2005

When people contact the government they can use a variety of channels. That is, they go in person to an office, use a telephone service, access information via the Internet, send a letter, or use a third party. Since the Australian Government first recognised the potential of online technology to improve service delivery in its 1997 Investing for Growth statement, it has articulated its policies and strategies for e-government in a number of papers. E-government involves government agencies delivering better programs and services online through the use of new information and communication technologies. The policy papers included Government Online-The Commonwealth's Strategy, launched in April 2000, and a new framework for e-government, Better Services. Better Government, launched in November 2002. Most recently, the Government released Australia's Strategic Framework for the Information Economy in July 2004. These papers outlined the broad directions and priorities for the future of e-government in Australia, and sought to maintain the momentum of agencies' actions under Government Online. One of its key objectives was for agencies to achieve greater efficiency in providing services and a return on their investments in ICT (Information and Communication Technology)-based service delivery. They also stated that investing in e-government should deliver tangible returns, whether they take the form of cost reductions, increased efficiency and productivity, or improved services to business and the broader community Implementation of the Government policy has led to considerable agency investment in ICT-based service delivery. However government policy also requires managers to ensure that program and service delivery is efficient and effective. Efficient and effective use of ICT has the potential to improve service delivery and to make financial savings. This paper outlines how people are using the channels to contact the government in Australia. It also examines the level of satisfaction they have with those services and their preferences and expectations. In addition, this paper aims at identifying the methods used by Australian Government to measure the efficiency and effectiveness of their delivery of services, and at assessing the adequacy of these methods.

• 동력기계공학회지
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• 제12권1호
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• pp.13-19
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• 2008

In this study, a variable induction and exhaust system is applied to turbocharged diesel engine to improve the volumetric efficiency, especially, in a low and transient engine speed range where much of the pollutant matters are expelled out. The volumetric efficiency is known as one of the most important factor which affects significantly engine performance, fuel economy and further emission and noise level. As the torque increase with the engine speed up, the gas flow in an exhaust pipe become pulsating and then has an effect on boost up capacity of air charging into the cylinder and expelling capacity to atmosphere simultaneously. But at a low and idling speed, the pulsation effect was not so significant. Accordingly, resonator was employed to compensate their loss. The variable induction system consists of the secondary pipe, resonator, intercooler, and torque variance were examined with extended operating conditions. In the mean time, for interpretation and well understanding for the phenomena of wave action that arising during intake and exhaust process between turbocharger and variable intake system, the concept of the combined supercharging was introduced. Some of results are depicted which deal with a pressure history during valve events of induction process. Consequently, by the governing of these phase and amplitude of pulsating wave, it enables us to estimate and evaluate for the intake system performance and also, designing stage of the system layout.

• 문화경제연구
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• 제19권2호
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• pp.171-193
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• 2016

본 연구는 중국의 광고산업의 지역화와 상대적 효율성을 분석하고 있다. 중국의 광고산업은 급속하게 성장하는 산업 중의 하나이다. 특히 지역경제발전수준이 높아지고 소비행태가 고급화되고 다양화될수록 지역광고시장의 규모는 더욱 발전할 것으로 예상된다. 본 연구는 이러한 지역적인 특성을 실증분석하기 위해 입지지수를 이용하여 지역특화정도를 비교하고 있다. 그리고 DEA-Window 분석 방법을 이용하여 광고산업의 지역별 상대적 효율성을 분석 비교하고 있다. 분석결과에 의하면, 첫째 광고산업의 상대적 효율성이 높은 지역일수록 지역특화 정도도 높게 나타난다. 이는 산업의 집중과 산업의 효율성 간에 관계가 있음을 나타낸다. 둘째 중국의 광고산업이 지역별로 다극화되고 있다는 점을 들 수 있다. 북경시를 중심으로 하는 거대한 발전축이 형성되고 있으며 상해시, 강소성, 절강성을 중심으로 하는 또 하나의 발전축이 형성되고 광동성을 중심으로 하는 발전축이 형성되고 있다. 셋째 중부지역과 서부지역의 광고산업이 비록 상대적 효율성은 크게 높지는 않지만 지역특화 정도는 높게 나타나는 지역들이 있다는 점은 향후 발전 잠재력을 나타내고 있다.

• 아태비즈니스연구
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• 제11권4호
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• pp.255-269
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• 2020

Purpose - This paper analyzes the market efficiency focusing on the long memory properties of the domestic futures market. By decomposing futures prices into yield and volatility and looking at the long memory properties of the time series, this study aims to understand the futures market pricing and change behavior and risks, specifically and in detail. Design/methodology/approach - This study analyzes KOSPI 200 futures, KOSDAQ 150 futures, 3 and 10-year government bond futures, US dollar futures, yen futures, and euro futures, which are among the most actively traded on the Korea Exchange. To analyze the long memory and market efficiency, we used the Variance Ratio, Rescaled-Range(R/S), Geweke and Porter-Hudak(GPH) tests as semi- parametric methods, and ARFIMA-FIGARCH model as the parametric method. Findings - It was found that all seven futures supported the efficiency market hypothesis because the property of long memory turned out not to exist in their yield curves. On the other hand, in futures volatility, all 7 futures showed long memory properties in the analysis, which means that if new information is generated in the domestic futures market and the market volatility once expanded due to the impact, it does not decrease or shrink for a long period of time, but continues to affect the volatility. Research implications or Originality - The results of this paper suggest that it can be useful information for predicting changes and risks of volatility in the domestic futures market. In particular, it was found that the long memory properties would be further strengthened in the currency futures and bond rate futures markets after the global financial crisis if the regime changes of the domestic financial market are taken into account in the analysis.

• International Journal of Computer Science & Network Security
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• 제21권6호
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• pp.23-28
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• 2021

The article discusses the features of adaptation of the parameters of the physical layer of data transmission in self-organizing networks based on unmanned aerial vehicles operating in the conditions of "smart cities". The concept of cities of this type is defined, the historical path of formation, the current state and prospects for further development in the aspect of transition to "smart cities" of the third generation are shown. Cities of this type are aimed at providing more comfortable and safe living conditions for citizens and autonomous automated work of all components of the urban economy. The perspective of the development of urban mobile automated technical means of infocommunications is shown, one of the leading directions of which is the creation and active use of wireless self-organizing networks based on unmanned aerial vehicles. The advantages of using small-sized unmanned aerial vehicles for organizing networks of this type are considered, as well as the range of tasks to be solved in the conditions of modern "smart cities". It is shown that for the transition to self-organizing networks in the conditions of "smart cities" of the third generation, it is necessary to ensure the adaptation of various levels of OSI network models to dynamically changing operating conditions, which is especially important for the physical layer. To maintain an acceptable level of the value of the bit error probability when transmitting command and telemetry data, it is proposed to adaptively change the coding rate depending on the signal-to-noise ratio at the receiver input (or on the number of channel decoder errors), and when transmitting payload data, it is also proposed to adaptively change the coding rate together with the choice of modulation methods that differ in energy and spectral efficiency. As options for the practical implementation of these solutions, it is proposed to use an approach based on the principles of neuro-fuzzy control, for which examples of determining the boundaries of theoretically achievable efficiency are given.

• Journal of the Korean Wood Science and Technology
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• 제32권6호
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• pp.57-66
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• 2004

To study the efficient usage of small diameter logs and woods containing defects such as knots, slope of the grain and decay, six types of finger-jointed woods with various finger profiles were made of poplar, pine and oak with different density. We investigated the effect of finger profile on static bending strength performances of finger-jointed woods. The efficiency of bending MOE, MOR and deflection showed the highest value in poplar finger-jointed wood with the lowest density of three species, and the lowest value in oak finger-jointed wood with the highest density of three species. The values markedly decreased with increasing finger pitch for finger-jointed wood glued with polyvinyl acetate (PVAc) resin for all tested species, whereas for the finger-jointed wood glued with resorcinol-phenol formaldehyde (RPF) resin, the influence of finger pitch on the efficiency of MOE was not found in all tested species, and those on the efficiency of MOR and deflection indicated the same trend as finger-jointed wood glued with PVAc resin in the case of pine and oak finger-jointed wood with higher densities. It was found that the values tended to decrease with increasing density of species on the whole and the desirable finger pitches were L (6.8 mm) for poplar, M (4.4 mm) for pine and S (3.5 mm) for oak in a view of economy. For finger-jointed wood glued with PVAc resin, the fitness between a tip and a root width of a pair of fingers δ of 0.5 mm indicated the highest efficiency of MOE for all species. And, the influence of δ on MOR was only found in oak finger-jointed wood glued with RPF resin and the desirable δ value for oak was 0.1 mm. However, it was found that the influence of δ on the strength performance was very small.