• Journal of Satellite, Information and Communications
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• v.9 no.2
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• pp.114-118
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• 2014

In this paper, we analyze the performance of a concatenated code with two different inner decoding schemes. One is the error-detecting inner decoding, and the other is the error-detecting-and-correcting inner decoding scheme. We compare the performances of the two decoding schemes for finite and infinite block length cases when the concatenated code is applied to slow frequency-hopping spread-spectrum multiple access (FH-SSMA) communication systems.

• International Area Studies Review
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• v.15 no.3
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• pp.307-324
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• 2011

The global economic crisis made most of governments to overcome the economic depression as well as the challenging tasks for global warming. It is not easy political vision to harmonize these two rabbits race, and thus it needs to be developed new paradigm for the sustainable development. Unfortunately, the traditional cost-approach based productivity could not resolve this trade-off relation. Therefore, the paper is aimed to develop new approach on the green productivity index with the DEA models in the 1st stage, and then based on these green productivity scores, the paper is analyzed the determinants of these green productivity in the 2nd stage among the G 20 countries. The empirical result shows that the effect of GDP, carbon intensity, and capital and labor intensity toward the green growth is positive on the green productivity, while the level of government efforts is not significant on the green productivity.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.5
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• pp.384-394
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• 1996

The propagation properties of square and Gaussian pulse signals on the microstrip line are investigated by using proper conventional models to meet the frequency range of a pulse, accuracy, and geometrical requirements of the microstrip line. Numerical integration technique which has its accuracy and is easily simulated, is used to obtain the time domain response of pulse signals. The dispersion of pulse signals is analyzed regarding to the relative permittivity $\varepsilon_r$, substrate height h, strip width w of the microstrip line and pulse width $\tau$ of signal pulse. The simulation results show that small relative permittivity and small rationale of w/h are advantageous for the dispersion of the pulse signals, and that pulse signals with small bandwidth cause smaller dispersion. The results of this paper are compatible to the trade-off determination of relative permittivity, substrate height, strip width and pulse width of signal pulse when a design of MIC and MMIC is necessary.

• Journal of Korean Society of Transportation
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• v.24 no.3 s.89
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• pp.7-15
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• 2006

A large sample can Provide more information about the Population. As the sample size Increases, analysts will be more confident about the survey results. On the other hand, the costs for survey will increase in time and manpower. Therefore, determination of the sample size is a trade-off between the required accuracy and the cost. In addition, permitted error and significance level should be considered. Sample size determination in surveys for O/D estimation is also connected with confidence of survey result. However, the past methods were usually too simple to consider confidence. Therefore, a new method for O/D surveys was Proposed and it was accurate enough, but it has too large sample size when we have current budget constraint. In this research, several minimum sample size determination methods for origin-destination survey under budget constraint were proposed. Each method decreased sample size, but has its own advantages. Selection of the sample size will depend on the study Purpose and budget constraint.

• Journal of KIISE:Information Networking
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• v.31 no.6
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• pp.556-565
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• 2004

A Sandbox has been widely used to prevent damages caused by running of unknown malicious codes. It prevents damages by containing running environment of a program. There is a trade-off in using sandbox, between configurability and ease-of-use. MAPbox, an instance system of sandbox, had employed sandbox classification technique to satisfy both configurability and ease-of-use [1]. However, the configurability of MAPbox can be improved further. In this paper, we introduce a technique to attach dynamic class facility to MAPbox and implement MAPbox-advanced one. Newly generated class in our system has an access control with proper privileges. We show an example for improvements which denote our system have increased the configurability of MAPbox. It was determined as abnormal by MAPbox although is not. Our system could determine it as normal. We also show our techniques to overcome obstacles to implement the system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.4
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• pp.88-94
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• 2004

The electrical design of the Ka-band antenna for the domestic Communications and Broadcasting Satellite (CBS) is described. The antenna has the offset Gregorian structure and is installed on the Earth-facing panel of the satellite. The electrical performance specifications for the antenna were determined from the required EIRP and G/T through the payload level performance analysis. This paper utilized the reflector shaping technology for the trade-off among the major performance parameters, resulting in compliance of all the parameters. The designed antenna shows 37.95 dBi EOC (End of Coverage) gain and 28.7 dB sidelobe isolation for transmit band, and 37.49 dBi EOC gain and 31.1 dB sidelobe isolation for receive band, The electrical performances of the antenna have been verified via the electrical testing of a manufactured EQM (Engineering Qualification Model) antenna.

• Korean Chemical Engineering Research
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• v.58 no.4
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• pp.550-564
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• 2020

Distillation columns are one of the main equipment used for the separation of chemical components in petrochemical process design. However, in spite of the efficient operation in wide range, and the advantage of data collection for equipment verification, the distillation columns are inherently known for high energy consumption and capital cost. Hence, the trade-off analysis needs to be done between investment cost and operation cost to develop the most economical distillation columns. This study was conducted using Aspen Plus, a popular process simulation program, in the pursuit of broad application by as many process engineers as possible. In this paper, design variables for optimization of distillation columns were defined to improve emphatically the design quality with reducing erratic practice of many engineers. In addition, by eliminating unnecessary reviewing step and establishing systematic and efficient procedures, the amount of time for design and human resources were minimized. Aspen Process Economic Analyzers (APEA) program was introduced in order to calculate the investment cost reliably, and the efficient systematic procedure for utilization of APEA was established.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.3 s.303
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• pp.31-40
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• 2005

In this paper, we develop an approach toward JSC(Joint Source-Channel Coding) method for MPEG-4 based FGS(Fine Granular Scalability) video coding and transmission in fixed and mobile receiving environment(Digital Audio Broadcasting, DAB). The source coder used MPEG-4 FGS video codec, the channel coder used RCPC(Rate Compatible Punctured Convolution) code and the modulation method used QPSK modulation. We have considered channel environment of AWGN and mobile receiving environment. This study determined optimum Trade-off point between source bit rate and channel coding rate in variable channel states. We compared FGS-JSC method and general single layer CBR(Constant Bit Rate) transmission. In this results, FGS-JSC was appeared better performance than CBR transmission.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.3
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• pp.98-108
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• 1999

The purpose of this research is to help outdoor space planning reflected real needs of apartment residents in the differentiation elements of outdoor space, by using USC trade-off game in three apartment complexes in Seoul. This game method was used to evaluate their preference, reliability of preference degree, satisfaction degree, requirement elements such as improvement, sacrifice, maintenance of present condition, and payment possibility for improving and maintaining present condition, in addition to their preference and payment possibility of differentiation of outdoor space in the apartment complex in the future. From the statical analysis, we found the following results: 1. Reliability of preference degree was valid, inasmuch as the first elements they preferred were the almost same as the last things. 2. Elements of preference were pedestrian ways, pedestrian security facilities, various athletic facilities, and variety and high-class facilities in a play ground. 3. Satisfaction degree of differentiation elements of outdoor space was low not only in total complexes but also in each complex. As a result of analysis, these elements were not satisfied with residents. 4. Most of the differentiation elements of outdoor space in three apartment complexes, except planting traditional trees, were required to improve and maintain present condition. The cost to improve and maintain these elements able to pay by them was about 2.18 million won. Through this result, these elements were not options but prerequisites for planning outdoor space in apartment complexes. 5. In the future preference elements of differentiation of outdoor space in apartment complexes were pedestrian and jogging ways, places with water, various athletic places and facilities, multi-function resting places, green spaces in experiences, pedestrian security facilities, various athletic facilities, variety and high-class facilities in a play ground, and payment possibility for these elements was about 3.20 million won.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7C
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• pp.735-742
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• 2006

In this paper, we explain the operation scheme and fixed-point design method of DFE (Digital Front End), which performs DC offset compensation, automatic frequency control, and automatic gain control over the input signal to the UE (User Equipment) receiver of IEEE 802.16e OFDMA-TDD system. Then, we analyze the performance of DFE under ITU-R M. 1225 Veh-A 60km/h channel environment. To optimize the fixed-point design of DFE, we reduce the number of bit resulted from calculation without performance degradation, leading to the decreased complexity of the operation in H/W, and design the Loop filter with considering trade-off between the Acquisition time and the Stability.