• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.397-401
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• 2008

Knowledge of dynamic characteristics of structural elements often can make difference between success and failure in the design of structure due to resonance effect. In this paper an analytical model of a cantilever beam having midpoint load is considered for structural optimization. This involves creating the geometry which allows parametric study of all design variables. For that purpose optimization of cantilever beam is elaborated in order to find the optimum geometry which minimizes its volume eventually for minimum weight using ANSYS. But such geometry could be obtained by different combinations of width and height, so that it may have the same cross sectional area yet different dynamic behavior. So for optimum safe design, besides minimum volume it should have minimum vibration as well. In order to predict vibration different dynamic analyses are performed simultaneously to solve the eigenvalues problem assuming no damping initially through MATLAB simulations using state space form for modal analysis, which identifies the resonant frequencies and mode shapes belonging to the lowest three modes of vibration. And next by introducing damping effects tip displacement, bending stress and the vertical reaction force at the fixed end is evaluated under some dynamic load of varying frequency, and finally it is discussed how resonance can be avoided for particular design. Investigation of results clearly shows that only structural analysis is not enough to predict the optimum values of dimension for safe design. Potentially this technique will meet maintenance and cost goals of many organizations particularly for the application where dynamic loading is invertible and helps a lot ensuring that the proposed design will be safe for both static and dynamic conditions.

• Journal of the Korean Ceramic Society
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• v.50 no.2
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• pp.142-148
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• 2013

Conventional cold isostatic pressing, slip casting, and filter pressing are not completely suitable for fabricating large plates because of disadvantages such as the high cost of equipment and formation of density gradient. These problems could be avoided by employing pressure-vacuum hybrid slip casting (PVHSC). In the PVHSC, the consolidation occurs not only by the compression of the slip in casting room, but also by vacuum sucking of the dispersion medium around the mold. We prepared the alumina bodies by the PVHSC in a static- or stepwise-pressure manner for loading up to 0.5 MPa using an aqueous slip. The green bodies were dried at $30^{\circ}C$ with 40 ~ 80% relative humidity. Under static pressure, casting induced a density gradient in the formed body, resulting in cracking and distortion after the firing. However, the stepwise pressure loading resulted in green bodies with homogeneous density, and the minimization of the appearance of those defects in final products. Desirable drying results were obtained from the cast bodies dried with 80% RH environment humidity. When sintered at $1650^{\circ}C$ for 4 h, the alumina plate made by stepwise-pressure casting reached full density (> 99.7% relative density).

• Korean Journal of Construction Engineering and Management
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• v.7 no.6
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• pp.141-150
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• 2006

As the law on the private sector investment in social infrastructure was amended in January of 2005, the government is aggressively promoting BTL projects but many trials and errors and problems are occurring. Especially, the Value-For-Money evaluation conducted by the responsible agencies to judge the appropriateness of the project found there was a conspicuous difference between the computed cost and the final contract sum. Accordingly, this study is aimed to grasp the problems in the current Value-For-Money evaluation and to improve it in order to proceed with BTL projects efficiently. To achieve this, through a relative comparison to the final contract sum, a clear standard for the items of Value-For-Money evaluation was presented and thus, a model that can ensure accuracy in computing the Value-For-Money was established so that a delay in negotiations can be avoided. If the Value-For-Money evaluation established in this study is used in assessing the appropriateness of unit prices for BTL projects for education facilities, a reasonable result can be expected to be drawn in selection and negotiations with contractors, and maintenance and Post-Operation-Evaluation(POE) of education facilities as well.

• Journal of Microbiology and Biotechnology
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• v.10 no.1
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• pp.75-80
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• 2000

An improved method of refolding recombinant human proinsulin from E. coli was presented. It was based on a two-stage stirred tank reactor in which denatured proinsulin-s-sulfonate was mixed instantaneously with a reaction buffer in the first stage reactor, and then fed to the second stage reactor. The mixture was stirred further for a total of 30h in the second stage reactor. In this system, unfavorable effects present due to the increase in reaction volume and protein concentration for protein refolding, which becomes significant in a large-scale operation, were avoided. Refolding yields of over 80% was obtained for achieving reaction volume of upto 50 l at protein concentration of 1 mg/ml. The optimum urea concentration was 1M. Refolding yield at the 1-1 reaction volume and protein concentration of 0.5mg/ml was increased about 2.5-fold, compared to that in a batch reactor. By increasing protein concentration in a two-stage refolding reaction, the cost for insulin production could be reduced, therefore, making this process economical.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.681-684
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• 2015

Power amplifier is an essential component for transmitting signals to a remote receiver in wireless communication systems. Power amplifier is a non-linear device in general, and the nonlinear distortion becomes severer as the output power increases. The nonlinearity results in spectral regrowth, which leads to adjacent channel interference, and decreases the transmit signal quality. To linearize power amplifiers, many techniques have been developed so far. Among the techniques, digital pre-distortion is known as the most cost and performance effective technique. However, the linearization performance falls down abruptly when the power amplifier operates in its saturation region. This is because of the severe nonlinearity. To relieve this problem, this paper proposes a new adaptive predistortion technique. The proposed technique controls the adaptive algorithm based on the power amplifier input level. Specifically, for small signals, the adaptive predistortion algorithm works normally. On the contrary, for large signals, the adaptive algorithm stops until small signals occur again. By doing this, wrong coefficient update by severe nonlinearity can be avoided. Computer simulation results show that the proposed method can improve the linearization performance compared with the conventional digital predistortion algorithms.

• Journal of the Korean housing association
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• v.20 no.3
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• pp.11-18
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• 2009

The purpose of this study is to propose a method of developing an improved Hanok. To achieve this, an investigation was carried out on the factors of the main floor plan in the improved Hanok development and an interview was conducted with residents who live in the improved Hanok development. The conclusions obtained through this study are as follows: First, The shape of 一 was marked at the highest in the Korean traditional plan types such as 一, ㄱ and 田. It is considered that this reduces the cost of construction by simplifying the structure of the roof. Second, the size was consisted of $5{\times}3$ Kan, the Korean traditional module that determines the number of columns and expresses the position of the inner wall. However, the Kan measure ments for the bathroom and multi-purpose room differed. Third, 57.6% of the 2 bedroom units were investigated. However, 60% of the residents preferred 3 bedroom units. Fourth, the results of the relationship between the living room and the kitchen showed that the residents preferred L+DK type to LDK type by 54.2% and 45.8% respectively. Fifth, the residents preferred a bathroom constructed next to the bedroom because they considered that the improved Hanok development would be used as an Inn during holiday periods. Moreover, they desired a plan where the bathroom could be directly entered from the outside. Sixth, the design for the improved Hanok development should have a suitable multipurpose-room because 72.5% of the residents have extended their house to accommodate such a room. Seventh, 61% of the improved Hanok units had an entrance space, which does not exist in Korean traditional houses. For this reason, the Korean traditional floor (: the Maru) was avoided due to its inconvenience.

• Journal of Fashion Business
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• v.5 no.1
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• pp.117-130
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• 2001

The purpose of this research focuses mainly on the establishment of: the image of the police that can be adopted to meet the demands of reality through the development of the design of policewomen's uniform in the times that require reestablishment of the image of the police; the image of the police that is appropriate for the organic structure of the society; and the image of the police that cooperate with the citizens. For background research I have considered the police and their uniforms from a theoretical point of view and have examined the process by which Korean policewomen's uniforms have changed. Actual research was carried out policewomen of Seoul Regional Police Station, was conducted and the results were utilized to figure out what the problem was. This research suggests an improvement measure by making four suits of summer and spring-and-autumn work-uniforms, and six suits of spring-andautumn and winter full-dress uniform. First the colors of work-uniforms and full-dress uniforms are not blue, which incites a feeling of coldness and stiffness, but are colors that are feminine and emit warmth---red, ivory, khaki, black, and beige. second pure, natural fiber is difficult to wash and is not an appropriate material for policewomen's uniforms when considering its cost and etc., fabrics that are a mix of synthetic fiber and natural fiber were chosen. Because mixed fabrics are cheaper and their ability to maintain shape is superior to that of natural fiber, mixed fabric is an appropriate material for policewomen's uniforms. third the feminine image of policewomen was considered; therefore, masculine image, which is rigid and strong, was avoided and the image was expressed in a serene and beautiful way. Also slim line was added to the current uniforms to emphasize feminine beauty. The conclusion of this study is that police officers in the 21st century want to be seen as the citizens cane and benevolent volunteers that live together with the citizens, not as suppressive and powerful people.

• Korea Journal of Hospital Management
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• v.5 no.2
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• pp.22-39
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• 2000

The purpose of this study was to determine the difference between estimated profit and utilization of medical equipment upon purchasing and actual results at one teaching hospital in Seoul, Korea Medical equipments over $100,000 from 1992 to 1997 were selected and results were as follows: 1. Twenty equipments out of thirty exceeded estimated profits and the difference was 3.98 billion won and ten equipments did not reach the estimated profits and 5.5 billion won was the difference. Diagnostic equipment exceeded the estimated profit which surgical equipment didn't. 2. Eleven equipments exceeded estimated utilization, which showed 100%. In the mean time, eighteen equipments didn't reach the estimated utilization, which was 71%. Diagnostic equipment showed the less estimated utilization than surgical equipment 3. Twenty-one equipments showed the 6.83 billion won profits and nine equipments showed the 1.6 billion won deficits. Diagnostic equipment was more profitable than surgical equipment. Finally. diagnostic equipment helped improving hospital management than surgical equipment. 4. Main factors which showed the big difference from the initial plan were lacking reasonable estimated method, no evaluation system for purchase, emphasis in medical treatment, excessive expenditure in maintenance, duplicated investment for medical equipment and leadership commitment. As a result. Substantial planning is required from the requesting department in consideration of estimated profit and utilization and systematic quality control is needed to confirm. Also, One-sided decision making should be avoided to purchase a high cost medical equipment and efforts should be made in examining carefully and developing a reasonable analytic method.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.54-62
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• 2001

Although claims and disputes may be never avoided in construction industry, until 1998, there are no systematic claims in the public sector in Korea. But, because of IMF, Contractors have been recognized that cost management is essential factor and contractual right can be demanded against the Public Orderer. Many affirmative effect such as, appearance of new professional service, prevention of lower quality construction, restrain of unnecessary budget expenditure, arrangement of duplicated or triplicated liability and revision of unnecessary administrative control may be anticipated through alleging claims, but in site representative manager and construction company may have ambiguous fear, somebody tried to allege claims. Therefore, to activate systematic construction claims, 32 public construction project claims alleged by contractors from 1998 to 2001 were analyzed, inactivated reasons of claims were examined and contractor's action plan to allege claims was suggested in this paper.

• Korean Journal of Optics and Photonics
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• v.28 no.1
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• pp.1-8
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• 2017

A method for inspecting defects in display substrates utilizing Fourier optics is proposed in this paper. A cost-effective inspection system can be realized with the proposed method, because it does not require a high-magnification microscope. Also, the proposed method can avoid tight tolerance for variations in displacement between substrate and camera, which is stems from shallow depth of field of the high-magnification microscope. In addition, possible damage caused by collisions between substrate and the inspection equipment can be avoided. The decision algorithm can be simpler than for a conventional inspection system, because spatial shift of periodic substrate patterns does not affect the intensity distribution of the diffracted light, by the Fourier transform property. The proposed method is explained with numerical studies, and experiments are carried out to check its feasibility for color-filter substrates of a liquid-crystal display.