• Journal of the Economic Geographical Society of Korea
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• v.25 no.4
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• pp.583-599
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• 2022

According to the discussion on the low-density economy in OECD industrial growth in remote area has played a central role in the members'economic recovery from the financial crisis in the mid-2000s. Based on the OECD's low-density economy this study examines the phenomena and spatial characteristics of industrial growth in peripheral areas of Korea. The growth of industries in the peripheral areas shows a similar growth characteristics as cases in the OECD members. Various manufacturing and service sectors as well as traditional sectors such as agriculture, forestry and fishing have grown in the peripheral areas since the mid-2000s. Firms in the peripheral areas form various cooperative networks to overcome the unfavorable regional conditions. The growth of new industries shows the possibility of path-dependent development in the periphery. Based on the results, implications on the policies for supporting the diversification of regional industries, setting flexible regional boundaries for policies, and linking policy sectors are derived.

• Journal of Technology Innovation
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• v.22 no.1
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• pp.89-117
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• 2014

Employing female in the field of science and engineering is becoming increasingly important with diversity and creativity emerging as key factors to build Creative Economy. Under these circumstances, it is necessary to recognize and discourage gender discrimination in the labor market by analyzing wages - the market value of labor which determines one's economic status. This study uses the Oaxaca-Ransom decomposition (1994) to analyze the gender wage gap and identify factors influencing the pay gap in science and engineering labor force. The results of this study are as follows: First, the average wage of female scientists and engineers reaches only 65% of that of male labor force, and the male scientist and engineers are superior in terms of personal attributes, for instance, education background. Second, looking at the factors that influence wages, wage premiums are associated with higher education background, older age, longer period of service, and weekly working hours for both male and female in managerial positions. Third, the wage decomposition shows that in the case of science and engineering labor force, the productivity difference by personal attributes reaches about 58%, and gender discrimination by the characteristics of the labor market stands at about 41%. This means the wage gap by productivity level in science and engineering labor force is wider, and the gender gap is smaller compared to non-science and engineering fields. However, the results of an analysis on specialties and education background of male and female scientists and engineers suggest that the discrimination against women is more serious when the percentage of the female labor force is low and the percentage of temporary workers in the labor market is high. In order to eliminate this discrimination, it is necessary to reduce the imbalance of female scientists and engineers in the labor market, among others, while female scientists and engineers, themselves, need to make continuous efforts to strengthen their capabilities.

• Journal of the Korean Society for Railway
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• v.20 no.1
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• pp.43-54
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• 2017

This paper analyzes the performance of two three-leg inverters and a five-leg inverter and proposes the optimal operation conditions in applying the five-leg inverter for the train propulsion system. The five-leg inverter offers a saving of two switches compared with the standard two three-leg inverters and it is possible to control two three-phase motors independently by using a control board. All of these features lead to a potential reduction in capital cost and miniaturization of system. In this paper, first, the analysis of the existing motor control method and PWM method for two-traction motor drive of urban railway is implemented. Next, the operation principle and performance of five-leg inverter is introduced. Through the analysis, when it applies the same motor control method and the same PWM method for three-leg inverter and five-leg inverter, the characteristic of motor's speed and torque is compared.

• The Journal of the Convergence on Culture Technology
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• v.4 no.3
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• pp.235-240
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• 2018

ICT converged smart factory started from German Industry 4.0 has been the driving force for the $4^{th}$ Industrial Revolution and the center of manufacturing innovation for major industrial countries. It will be developed according to industry characteristics of each country. Korea is relatively later than other competing countries in the smart factory area. So, the government is establishing related policy and tendering all sorts of supports for smart factory mainly to the small and medium-sized enterprises to spread over the manufacturing industry. It is necessary for government to categorize among similar manufacturing industry and make them share digitalized production information mutually. It will be more effective method for securing global competitiveness than the uniform support. Also, large companies need to establish cloud based production forecasting system over similar industry and share it with other companies rather than expansion of individual smart factory. Mutual development in the manufacturing industry will be realized when the small and medium-sized enterprises and large companies take part in the cooperating ground of smart factory.

• Journal of Biosystems Engineering
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• v.2 no.1
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• pp.33-48
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• 1977

Transporting agricultural products and the other material by the two-wheel-tractor (power-tiler)and trailer system may be one of its most widely used farming functions.The safety and hitching load for all the previaling performing conditions may be the general concern over the operation of the tiller-trailer system. In this study, a mathematical model to determine the static and dynamic forces excerting on the hitch point were developed . Based on the analysis of the model and the field measurements. the limiting hitching load and critical slope were analyzed. The results of the study are summarized as follows ; 1) The limit angle of slope land for the safety steering that two-wheel tractor-single axle trailer system was able to transport agricultural products was the direct angle (${\gamma}$) = 8 ; the cross angle$\beta$) 15 ; and it was decreased in accordance with the increase of carrying load ($W_4). 2) The critical velocity for safe operation in case of running on downward hill road was about 1.08m/sec. 3) The limiting carrying load for the safe steering was W$_4$=600kg. The degree of the safe steering for different braking methods was given in order as follows ; Simulataneous braking the tractor and trailer , braking the trailer only, and braking tractor only. 4) Among the three components of impact loads excerting on the hitch point, the component in the lateral direction ($P_{Vy}$) was near zero in spite of increase of hitching load ($W_4) , while the components in the other two mutually perpedicular directions ($P_{Vx}$ and ($P_{Vz}$) ) had larger values in horizontal plane than those in the slope lands. 5) Moment of forces on the lateral direction (M$y$) had the largest value among the three components of impact moment acting on the hitch point, however all the components were sharply increased in accordance with the increase of hitching loads ($W_4. Three components of the moment were the negative values.

• Journal of Korea Port Economic Association
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• v.24 no.2
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• pp.1-17
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• 2008

In this paper the cargo transportation were forecasted for the North Port in Busan through time series models. The cargo transportation were classified into three large groups; container, oil, general cargo. The seasonal indexes of existing cargo transportation were firstly calculated, and optimum models were chosen among exponential smoothing models and ARIMA models. The monthly cargo transportation were forecasted with applying the seasonal index in annual cargo transportation expected from the models. Thus, the cargo transportation in 2011 and 2015 were forecasted about 22,900 myriad ton and 24,654 myriad ton respectively. It was estimated that container cargo volume would play the role of locomotive in the increase of the future cargo transportation. On the other hand, the oil and general cargo have little influence upon it.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.64-70
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• 2018

Rollover is a major concern for vehicles with a higher center of gravity and for improving driving performance. This study investigates a tilting system to prevent rollover, which was successfully implemented for high-speed trains. It may be useful to apply the concept of the tilting system to a large truck such as a trailer. Even a small adjustment in the tilting angle can improve the driving stability during a steep turn. The equation of motion was derived from a dynamic model of the trailer with the tilting system. The balance of the centrifugal force and normal force determines the rollover critical speed for a given radius of the turn and load. To obtain a more conservative criterion, the rollover critical state was defined as the instant when any side wheel loses contact with the road. To actuate the tilting system, the optimal tilting angle must be calculated from the steering angle and the vehicle speed. Using a simplified model of a large truck, the effects of the tilting angle and load on the rollover critical speed were investigated.

• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.135-140
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• 2012

Interior Permanent Magnet Synchronous motors (IPMSM) with concentrated winding are superior to distributed winding in the power density point of view. But it causes huge amount of eddy current losses on the permanent magnet. This paper presents the optimal permanent magnet V-shape on the rotor of an interior permanent magnet synchronous motor to reduce the core losses and improve the performance. Each eddy current loss on permanent magnet has been investigated in detail by using FEM (Finite Element Method) instead of equivalent magnetic circuit network method in order to consider saturation and non-linear magnetic property. Simulation-based design of experiment is also applied to avoid large number of analyses according to each design parameter and consider expected interactions among parameters. Consequently, the optimal design to reduce the core loss on the permanent magnet while maintaining or improving motor performance is proposed by an optimization algorithm using regression equation derived and lastly, it is verified by FEM.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.5
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• pp.547-554
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• 2010

RFID is core technology to lead ubiquitous computing, and attract the notice of the world. It also improves social transparency, creates employment, and invigorates the allied industries. However, The technical characteristic with RFID has some problems with security and privacy. The commercialization of RFID is delayed due to these problems. This paper introduces the technical method to find solutions about an invasion of privacy to be due to introduce RFID system. First, this method applies Hash-Chain proposed by M. Ohkubo and some other researchers. The more tags increase, the more it demands lots of computation time. We divide SPs equally to solve these problems. And then, We'll suggest solutions to shorten the identification time of tag by implementing SPs with multi nodes of Grid environment at the same time. This makes it possible to keep the privacy protection of RFID tag, and process RFID tag in real time at the same time.

• Journal of the Korea Convergence Society
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• v.6 no.2
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• pp.49-55
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• 2015

Quantum dot technology can be complementary application of the bulk material, and that a wide range of applications that can take advantage of the characteristic convergence technology. With the development of quantum dot technology, it is important to analyze Marketability of quantum technology, business opportunity. In this study, patents, papers, market, analysis of the project will be to investigate the quantum information research trends. Research results are expected to be used as a basis for research and development path setting and strategic planning of the quantum dot. In particular, this study found the performance of quantum dot research through patents and papers analyzed. In addition, fast-growing field, the field to lead the commercialization were derived. Compared to the advanced research and national research was to diagnose the domestic research into quantum dots.