• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4C
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• pp.380-387
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• 2002

In this paper, the effect of the phase noise of a local oscillator on the ACPR of a transmitter and the reception sensitivity of a receiver to meet the TIA/EIA/IS-98-D for the CDMA mobile station was analyzed. And the optimum condition for performance of the local oscillator was suggested. It was found that the phase noise level of the local oscillator in a receiver and a transmitter should be below -138.3dBc/Hz and -120dBc/Hz, respectively, at 900kHz offset. It was confirmed that the reception sensitivity and ACPR efficiency were satisfactory when the signal of the local oscillator to the down-converter of a receiver with the phase noise level of less than -138.3dBc/Hz is supplied to the up-converter of the transmitter.

• Journal of the Korea Institute of Building Construction
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• v.9 no.2
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• pp.69-76
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• 2009

Recently, the twenty-first century is called "the age of localization and regionalization" in Korea. So, local government should need to keep balance between the existing administrative management and new management strategies based on CEO's mind in order to deal with the situation of such that(the age of localization and regionalization) and improve efficiency of public service. In addition, they build public buildings after that they should operate and maintain them regularly. However, Korea local governments have tried to run many projects to expand insufficient local finance that was only for profit oriented public projects without considering management. Therefore, this paper is a basic study to establish and suggest the reasonable operation plan for local government by examining and reviewing actual operation condition in the public buildings. With the evaluation method which is demanded from public construction management to introduce a civil management technique manages an investment mind standard and management basis of assessment, proposes 8 sides of financial affairs, real estate maintenance and facility management, achievement evaluation, environmental safe crisis management, judiciary and explanation responsibility with base.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.5
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• pp.959-974
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• 2012

Group signature schemes were made for serving anonymities of signers, but the group signature schemes have been seldomly adapted to the real-world applications because of their low computation and space (i.e. signature length) efficiency, complicated construction, limited user management, and so on. Kang, Hwang, etc. performed the study about the local linkability that is for helping group signature schemes to be adapted more easily to the real world. In this paper, we investigate the nature of local linkability, which did not deal with well in the previous studies, in detail and perform the formal proof for the security of special entities who hold the local linkability.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.381-385
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• 2009

This paper describes performance characteristics of a centrifugal fan having a different volute casing. The centrifugal fan has a backward blade type, and is used in a refuse collecting system. The flow characteristics inside the components are analyzed by three-dimensional Navier-Stokes analysis, and also compared to the results by experiments. Distributions of pressure and efficiency obtained by numerical simulation has a good agreement with the experimental results. Throughout the numerical simulation of the centrifugal fan, a fan efficiency is increased by decreasing local losses in the blade passage. It is found that the fan efficiency is enhanced by decreasing the distance between the shroud of a impeller and casing. Detailed flow analysis is also analyzed and discussed using the results obtained by numerical simulation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.2
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• pp.103-108
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• 2009

Local exhaust system used in toilet and cooking place of low-rise public house installed roof ventilator at terminal of stack. There are many high riser public houses in Korea. These buildings were not viewed as being major contributors to exhaust pollutants producted in indoor. It was because many engineers thought that exhaust in high riser public house depends on stack effect. But Neutral pressure level represents in a terminal of stack with air tightness for the best exhaust efficiency. Thereby, lower floors have the worst indoor air quality. This paper focuses mainly on the exhaust efficiency improved by roof fan with motor installed in high riser public house. It is observed there is higher exhaust efficiency than the existing natural roof ventilator.

• Journal of environmental and Sanitary engineering
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• v.11 no.1
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• pp.83-91
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• 1996

It is not too much to say that the territorial inhabitants' concerns are wholly c concentrated on the environmental preservation-problem and development-problem in Korea given effect to the local self-government system. At a time like this I was studied the effect on nutrients removal through lighting period in aerobic high rate pond and we know that waste stabilization pond method is the most economical and energy saving wastewater treatment technology than others. At the results which was studied through operating the reactor-l artifically main-tained at a temperature, $25^{\circ}C$, a light intensity, 3000lux, and a lighting period, 24hrs and the reactor-2 artifically maintained at a tern야rature, $25^{\circ}C$ and a light intensity 3000lux, and a lighting period period, 12hrs, It has appeared for 24hrs.-lighting period -reactor-1 to be prior to the reactor-2. The attained results are that 1. reactor-1 is prior to reactor-2 on oxygen-generation 2. reactor-1 is prior to reactor-2 on algal production 3. COD removal efficiency, 90.76%, T-N removal efficiency, 80%, T-P removal e efficiency, 74.47 % in reactor-2, in reactor-1 COD removal efficiency, 94.85 %, T-N removal efficiency, 98.07%, T-P removal efficiency, 72.13% are, so the treatment efficiency of reactor-1 is more excellent than things of reactor-2 4. it appeared that the detention time is 8, 9days.

• Journal of Korea Spatial Information System Society
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• v.2 no.2 s.4
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• pp.59-74
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• 2000

Because efficiency of the 1st-phase NGIS investment(1995-2000) has not been clearly measured, the action taken in the 2nd-phase NGIS project requires NGIS budgets to be evaluated in terms of effectiveness. Especially, the effective investments in local governments are critical for the NGIS projects, because they execute the much larger amount of budgets in total than other GIS projects. As indicated, for the successful NGIS implementation, it is important to obtain continuous political and financial supports from decision makers. As a persuasion measure for the budget appropriation, CBA(Cost-Benefit Analysis) and CEA(Cost-Efficiency Analysis) can play an important role for the decision makers. The major concern of this paper is how to measure the costs and benefits of the GIS implementation by considering important characteristics of the GIS projects in local governments, and existing theories are reviewed for this concern. The GISs in local governments can have different stages in terms of its evolution and the effectiveness of the applications can be represented variously. To identify categories for measuring costs and benefits of the various GISs, case studies and success stories are reviewed from both the foreign and domestic research. The categories of costs and benefits are determined from the tangible and intangible aspects. The categories for the quantitative and qualitative measure are proposed to evaluate the GISs in local governments. After measuring costs and benefits, three key evaluation methods in cost-benefit analysis are suggested as follows: 1) the benefit: cost ratio (B/C), 2) Internal Rate of Return (IRR), and 3) the net present values (NPV) of the costs and benefits. The sensitivity and uncertainty analysis are also helpful to make a decision for the GIS budget appropriation in local governments. In conclusion, although cost-benefit analysis is not an easy undertaking, it is certain that it can play an important role in the future for the GIS funding decisions in local governments.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2006.11a
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• pp.260-266
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• 2006

The construction of settlement house in a permanent rental housing development area started between 1989 and 1992, planning of supplying two hundred fifty thousand residences, settlement house became compulsory as a welfare facilities. As a part of Welfare program for low income families, number of settlement housing increased dramatically, also domiciliary welfare center was beginning to set up as a branch of settlement housing to strengthen its service towards families and local communities, thus numerous social welfare organizations play a crucial part in resolving a welfare problem for low income families while satisfying local community's needs. However, despite of these efforts, the number if institutions cannot handle demand of local community's needs and number of welfare institution programs. as a solution, the alternation of space is being used, however, it did not solve basic problem, even worsen in terms of space efficiency.

• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.4
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• pp.1-18
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• 2007

In this paper, we develop an adaptive genetic algorithm (aGA). The aGA has an adaptive scheme which can automatically determine the use of local search technique and adaptively regulate the rates of crossover and mutation operations during its search process. For the adaptive scheme, the ratio of degree of dispersion resulting from the various fitness values of the populations at continuous two generations is considered. For the local search technique, an improved iterative hill climbing method is used and incorporated into genetic algorithm (GA) loop. In order to demonstrate the efficiency of the aGA, i) a canonical GA without any adaptive scheme and ii) several conventional aGAs with various adaptive schemes are also presented. These algorithms, including the aGA, are tested and analyzed each other using various test problems. Numerical results by various measures of performance show that the proposed aGA outperforms the conventional algorithms.

• Steel and Composite Structures
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• v.24 no.3
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• pp.339-349
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• 2017

In this paper, a conventional refined plastic hinge analysis is improved to account for the effects of local buckling and lateral-torsional buckling. The degradation of flexural strength caused by these effects is implicitly considered using practical LRFD equation. The second-order effect is captured using stability functions to minimize modeling and solution time. An incremental-iterative scheme based on the generalized displacement control method is employed to solve the nonlinear equilibrium equations. A computer program is developed to predict the second-order inelastic behavior of space steel frames. To verify the accuracy and efficiency of the proposed program, the obtained results are compared with the existing results and those generated using the commercial finite element package ABAQUS. It can be concluded that the proposed program proves to be a reliable and effective tool for daily use in engineering design.