• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1451-1454
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• 2002

In recent years, there are growing concerns about land mobile satellite (LMS) communication systems and mobile stratospheric communication systems (SCS) for the purpose of service upgrade of personal and mobile communications in near future. It is important to possess accurate channel model for prediction of the above system performance. Thus, in this paper, we evaluate the bit error rates of a coded BPSK system based on realistic channel model which can be applied to stratospheric communication systems. The channel data was made by fitting the parameters of probability distribution model to measured data. This approach was proposed by Corraza〔1〕and modified by You〔2〕. And also the effects of channel codings on the system performance are analyzed. As results, we can get the performance curve characteristics on realistic Rician log-normal fading channels with various communication environments.

• Journal of the Korean Institute of Landscape Architecture
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• v.23 no.3
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• pp.94-105
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• 1995

Purposes of this study were to apply and examine that the importance-performance analysis(IPA) could be a useful park management tool. The IPA is an easily-applied technique developed in marketing field to measure attribute importance and performance. It displays them simultaneously on a 4-quardrant action grid; therefore, park managers can upgrade current services and address marketing strategies for various user segments. The children's grand park was selected as a study are. Two different types of questionaires were utilized for data analyses. They were collected from one respondent by on-site distribution or by mail survey, because attribute importance and performance should be rated before and after visiting a park, respectively. Then, total data was segmented systematically by 2 variables-age and benefit sought. Action grids from order to meet the needs of each segment. Several comments on both data collection methods and segment variables selection were described to improve the IPA in recreation settings for future researches.

• Journal of the Korea Society for Simulation
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• v.10 no.1
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• pp.73-82
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• 2001

The main idea behind the Intelligent Networks (IN) concept is the separation of switching functionality from the service control, in order to meet various service requirements of subscribers and development of new services in time. On the increase of subscriber and for high quality of service, the IN upgrades its service systems, and there are a number of ways depending on the system architecture and the characteristics of services. This paper compares two alternatives, traces the performance of them by means of the simulation technique, and finally puts a rule to select one of them.

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.226-231
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• 2008

40 Gbps WDM Systems using super-Gaussian RZ pulses have been studied by numerical simulation to optimize their performance. The assumption of standard single mode fiber is valid when existing WDM systems are required to upgrade their performance to 40Gbps. It is shown that the standard single mode fiber can transmit optical signals over 720 km (Q > 10) by optimizing optical and electrical filter characteristics at the receiver and by compensation of dispersion. However, it is also shown that ${\pm}0.3%$ dispersion compensation tolerance per span (80 km) could prohibit transmitting over 320km (Q > 10). In addition, a duty cycle of less than 0.4 degrades system performance significantly.

• Journal of Aerospace System Engineering
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• v.15 no.4
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• pp.47-56
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• 2021

In the management of aged aircraft, used avionics equipment is replaced with new ones to improve the performance and extend the life cycle of the aircraft. In this case, considering airworthiness, it is necessary to check whether the aircraft has sufficient electricity in the electric generator or the electrical distribution system, in accordance with the maximum electricity consumption of the new avionics equipment. Accordingly, this paper reviews a few airworthiness standards and guidelines associated with the electrical load analysis when an avionics equipment is upgraded in an aged aircraft, and proposes an optimization method for the electrical load analysis. In addition, it verifies the validity of the proposed method via the QFD theory, and is currently available for upgrading the performance of aged aircraft.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.621-626
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• 2005

Recent increases in construction costs on Korean public works projects, largely due to change orders caused by poorly elaborated design, become a motivation of applying VE process in Korean construction industry. The Seoul Toll Plaza project, recently value analyzed by four VE teams, demonstrates how value management helps save time, money and increase functional performance. The objective of this project is to upgrade and expand existing pay and ticket booths system on "Kyungboo Express Highway", the main artery for the Korean peninsula linking Seoul to Pusan. The value management study generated several innovate alternatives capable of saving up to 50% of project cost from the baseline project plan.

• International journal of advanced smart convergence
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• v.9 no.1
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• pp.121-131
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• 2020

We study empirically analyzes the relationship between the leadership styles and management strategies of executives perceived by members of small and medium venture companies through organizational performance through SPSS 24.0. The empirical results are as follows. First, the hypothesis that the strategic leadership of the one-level management team had a significant influence on the management strategy showed that strategic leadership (strategic direction, strategic control, maintaining effective organizational culture, ethical management, human resource development, competency development) The relationship between positive cost, strategy of differentiation, and strategy of concentration was positive. Second, the hypothesis 2 management strategy (cost advantage strategy, differentiation strategy, centralization strategy) was statistically significant for both organizational performance (financial performance and non-financial performance). Therefore, management strategy implemented by management acts as a factor to improve organizational performance. Therefore, the execution ability of management strategy should be strengthened. Third, hypothesis 3 (Strategic Direction, Strategic Control, Maintaining Effective Organizational Culture, Ethical Management, Human Resource Development, Competency Development) could be identified as an important role factor for financial and non-financial performance. The organizational performance of SMEs has been a key factor in the strategic leadership and management strategy implemented by management. Therefore, the establishment and implementation of various practical measures to upgrade this were continuously required.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.5
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• pp.1068-1072
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• 2011

Hydrogen Fuel Cell Vehicle(HFCV) is system that uses electrical energy of fuel cell stack to main power source, which is different system with other vehicles that use high-voltage, large-current. Isolation performance of this system which is connected with electrical fire and electrical shock is important point. Isolation resistance of electric installation is divided according to working voltage, it follows criterion more than $100{\Omega}$/VDC (or $500{\Omega}$/VAC) about system operation voltage in a hydrogen fuel cell vehicle. Although measurement of isolation resistance in a hydrogen fuel cell vehicle is two methods, it uses mainly measurement by megger. However, the present isolation resistance measurement system that is optimized to use in electrical facilities is unsuitable for isolation performance estimation of a hydrogen fuel cell vehicle because of limit of maximum short current and difference of measurement resolution. Therefore, this research developed the isolation resistance measurement system so that may be suitable in isolation performance estimation of a hydrogen fuel cell vehicle, verified isolation performance about known resistance by performance verification of laboratory level about developed system, and executed performance verification through comparing results of developed system by performance verification of vehicle level with ones of existing megger. Developed system is judged to aid estimation and upgrade of isolation performance in a hydrogen fuel cell vehicle hereafter.

• Journal of the Korean Institute of Educational Facilities
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• v.19 no.4
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• pp.29-38
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• 2012

Recently large scale earthquake s are occurred around the world following the damage of buildings. So the interest of preparing for earthquake seismic design and seismic performance has becoming high. School buildings are though used for educational purpose; they are also used as emergency shelter for local residents during earthquake disaster. However, the current seismic design ratio of our country (Korea) is 3.7% and if massive earthquake is occurred it follows a serious damage. In order to overcome this situation, seismic performance evaluation is carried out for existing school building and an accurate and appropriate seismic retrofit is required based on performance evaluation to upgrade the existing school buildings. In this paper, nonlinear static analysis on existing school buildings for ATC-40 and FEMA-356 are carried out using the capacity spectrum method to evaluate seismic performance and to determine the need for retrofitting. In addition, after reinforcement to verify the effect of retrofit enhance the seismic performance is applied the seismic performance evaluation is carried out to verify the effect of seismic retrofit time history analysis using nonlinear dynamic analysis is also performed and nonlinear behavior of earthquake load of seismic retrofit of structures was also investigated.

• Journal of the Korea Safety Management & Science
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• v.16 no.1
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• pp.221-230
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• 2014

The purpose of this study is to examine the influence that factors for a successful venture have on business performance. To fulfill this goal, factors for a successful venture are presupposed as the four elements of business creator, technological innovation, type of strategy, and organization, while business performance is set as subordinate variable, with a view to creating a model and establishing a hypothesis for a positive analysis. Data collection for the positive analysis was conducted using a questionnaire, and as for sampling, of the companies located in Seoul and greater metropolitan region and registered with Small and Medium Business Administration as of late December 2012, 98 companies have been selected for the final data. And I have come up with the two following results. First, factors for venture success have all proven to exercise statistically significant influence on business performance. Second, of all factors for venture success, business creator and technological innovation exercise huge influence on business performance, as compared to the other factors. From these two conclusions, it is understood that to upgrade business performance of a venture, business creator and technological innovation should be given priority over the other factors.