• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.7
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• pp.1448-1458
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• 1997

In this paper the reverse link of the GLOBALSTAR-the representative CDMA LEO satellite system and LEO mobile satellite channel are developed by the SPW software simulation tool. And the performance of the system is evaluated. GLOBALSTAR is designed to give cellular-type service to hand-held user terminals through a constellation of 48 LEO satellites in circular orbites with 1414 Km altitude. Since LEO mobile satellite system communicates with mobile unit, it is suffered from severe multipath fading and shadowing. The fast mobility of LEO satellites makes the channel condition time vering. So, the LEO mobile satellite channel is different from land mobile channels. In this unique LEO satellite channel, it is shown that the performance of the GLOBALSTAR reverse link is varied according to the elevational angle, but this variation is overcome by satellite path diversity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.5
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• pp.523-532
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• 2019

Microservice architecture focuses on dividing it into small and lightweight services to build for the purpose of performing very close business functions. So it tends to concentrate only on agility, productivity, reliability, and ease of deployment of software development. Microservice architecture considers database as just a file or storage for storing and extracting data, emphasizing that data quality can be sacrificed for convenience and scalability of software development. Database reverse engineering for understanding database structure and data semantics is needed for data utilization for business decision making. However, it is difficult that reverse database engineering is applied in microservice architecture that neglects data quality. This study proposes database reverse engineering method that utilizes master data to restore the conceptual data model as a solution. The proposed method is applied to the return service database implemented by microservice architecture and verified its applicability.

• Journal of Korean Society of Forest Science
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• v.103 no.2
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• pp.278-286
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• 2014

Forestry management problems in South Korea have been caused by small and scattered forest lands, aging forest owners, and the increase of absentee forest owners. To solve these problems, it is a time to consider the introduction of forest land bank system for the expansion of forestry management scale, the effective management of neglected forest lands, and the stable livelihood support for aged forest owners. Therefore, this research implemented the questionnaire survey of necessity, expectation, willingness to use, and introduction plans for the forest land bank system in order to examine the feasibility and demand of the system focused on forest owners, non-forest owners, and people who return to the farm. The questionnaire survey was conducted for 262 of resident forest owners, 152 of absentee forest owners, 427 of non-forest owners, and 101 of people who return to the farm. 77.5% of forest owners and 63.8% of non-forest owners agreed with the necessity of the introduction for the forest land bank system. Both forest owners and non-forest owners would prefer to use forest land reverse mortgage and leasing among projects of the forest land bank. In addition, 75% of people who return to the farm also expected that forest land bank would be helpful to their rural and mountain life, and they would have higher preference to participate in leasing and buying forest lands than other projects. Based on the outputs of the feasibility and demand survey in this research, this study can play a key role in determining basic direction, major functions, types and range of projects as well as providing information for establishing policies of the forest land bank system.

• Journal of Korea Port Economic Association
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• v.24 no.3
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• pp.147-165
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• 2008

Since 2000, e-commerce has been increased continuously in its quantity and quality. The growth of e-commerce has resulted in some diversities of distribution channels, and its characteristics of not-spot trading and limited market scale has urged the on-line market to play a role of assistance to off-line market. e-Commerce causes not only the flow of forward logistics, but also that of reverse logistics with every purchasing, which is a very critical factor to hesitate for consumers to purchase the products as well as increase the price of the products. Concern about the reverse logistics by sellers and buyers influences the level of price and purchasing activity of consumers. This study firstly is to lift the awareness of the efficient control of reverse logistics with reviewing the recent change of logistics environment and phenomena of reverse logistics. Secondly we find the factors generating the reverse logistics and look into its questions, and thirdly offer not only the ways to minimize the phenomena of reverse logistics, but also a efficient control system for reverse logistics. We additionally aim to contribute to prevent the price of the products from rising and raise the customers' satisfaction through minimizing the phase of reverse logistics.

• The Journal of Asian Finance, Economics and Business
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• v.1 no.3
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• pp.5-16
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• 2014

This study aims to examine the dynamics of price changes and trading volume of Kuala Lumpur Options and Financial Futures Exchange (KLOFFE) from 2000 to 2008. With augmented analysis, our results support two hypotheses. First, under information spillover, our findings support noise traders' hypothesis as the time span for variance of past trading volume to cause variance of current return is found to be asymmetric under bull and bear markets. Second, looking at the dynamic relation between volume and volatility of price changes, our findings support Liquidity-Driven Trade hypothesis as past trading volume and subsequent volatility of return exhibit positive correlation. In terms of investors' behavior in response to the news, we find that investors are more risk taking in bull market and more risk reverse in bear market. Our study suggests that investors should adjust their strategy in the futures market in a dynamic manner as the time span of new information arrival is not consistent. Also, uninformed investors with information asymmetry should expect noninformational trading from informed investors to establish their desired positions for better liquid position.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.4
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• pp.443-450
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• 2016

The linearization technique for low noise amplifier (LNA) has been implemented in standard $0.18-{\mu}m$ BiCMOS process. The MOS-BJT derivative superposition (MBDS) technique exploits a parallel LC tank in the emitter of bipolar transistor to reduce the second-order non-linear coefficient ($g_{m2}$) which limits the enhancement of linearity performance. Two feedback capacitances are used in parallel with the base-collector and gate-drain capacitances to adjust the phase of third-order non-linear coefficients of bipolar and MOS transistors to improve the linearity characteristics. The MBDS technique is also employed cascode configuration to further reduce the second-order nonlinear coefficient. The proposed LNA exhibits gain of 9.3 dB and noise figure (NF) of 2.3 dB at 2 GHz. The excellent IIP3 of 20 dBm and low-power power consumption of 5.14 mW at the power supply of 1 V are achieved. The input return loss ($S_{11}$) and output return loss ($S_{22}$) are kept below - 10 dB and -15 dB, respectively. The reverse isolation ($S_{12}$) is better than -50 dB.

• Journal of KIISE:Software and Applications
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• v.32 no.9
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• pp.847-852
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• 2005

Over the last decade, numerous complexity measurement techniques for Object-Oriented (OO) software system have been proposed for managing the effects of OO codes. These techniques may be based on source code analysis such as WMC (Weighted Methods per Class) and LCOM (Lack of Cohesion in Methods). The techniques are limited to count the number of functions (C++). However. we suggested a new weighted method that checks the number of parameters, the return value and its data type. Then we addressed an effective complexity measurement technique based on the weight of class interfaces to provide guidelines for measuring the class complexity of OO codes in reverse engineering. The results of this research show that the proposed complexity measurement technique ECC(Enhanced Class Complexity) is consistent and accurate in C++ environment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.9
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• pp.40-44
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• 2006

This study investigated a new tuneable bandpass filter based on coplanar waveguide coupled line structure, and using the varactor diode for tuning the center frequency of the filter. The filter was designed by a commercial simulator and had a tuning range of 180[MHz] from 0.95[GHz] to 1.13[GHz]. The filter acceptable values regarding the insertion loss was less than 3[dB] and its return loss greater than 12[dB]. The figure of merit of the implemented tuneable filter increased with the reverse bias voltage up to 14[V] on the varactor diode. The proposed filter has a promising future as it can be used in integration processes and in various materials as substrate.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.39-40
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• 2014

In this paper, a novel 12/8 segmental rotor type switched reluctance motor (SRM) is proposed. Different from conventional structures, the proposed rotor consists of a series of discrete segments, and the stator is constructed from two types of stator poles: exciting and auxiliary poles. Moreover, in this structure short flux paths are taken and no flux reverse exists in the stator. While the auxiliary poles are not wound by the windings, which only provide the flux return path. Compared with conventional 12/8 SRM, the proposed structure increases the electrical utilization of the machine and decreases the core losses, which may lead to high efficiency. To verify the proposed structure, finite element method (FEM) is employed to get static and dynamic characteristics. Finally, a prototype of the proposed motor is tested for characteristics comparisons.

• Journal of Korean Institute of Industrial Engineers
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• v.34 no.4
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• pp.398-407
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• 2008

We consider a product recovery system that a single product is stocked in order to meet a demand from customers who may return products after usage. This paper addresses a problem of when to release a procurement process to replenish serviceable inventory and how many new products to procure. The structure of the optimal procurement policy is examined and numerically identified as a monotonic threshold curve. A numerical procedure is presented to jointly find the optimal procurement order size, optimal procurement policy, and optimal discounted profit. Sensitivity analysis also indicates that these optimal performance measurements have monotonic properties with respect to system parameters.