• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.484-485
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• 2003

We report on the optimization of the fabrication process of hybrid sol-gel thin film deposition to produce low cost $1 {\times} 16$ splitters for optical communications. We learn that sol-gel film thickness is dependent upon the spinning speeds and viscosity of the sol-gel solutions and refractive index upon the dopant concentrations of Al and Zr in the sol solutions. We could find the optimized physical conditions to achieve the desired thickness of core and cladding layers. We will further carry out the fabrication and measurements of insertion loss, polarization dependent loss (PDL), etc. for the performance of fabricated splitter devices.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2004년도 제5회 정기학술발표대회 논문집
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• pp.494-499
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• 2004

국내 건설사업의 경쟁력은 국내적으로 수주감소 등으로 인하여 치열한 경쟁상황을 맞고 있으며, 국외적으로 건설선진국 뿐만 아니라 경쟁국가에도 경쟁력이 취약한 상태이다. 이를 극복하고 건설 경쟁력을 확보할 수 있는 방안이 제시되어야 한다. 따라서 본 연구에서는 건설사업 단계별로 내재된 낭비요소를 제거하여, 비용절감효과를 극대화 할 수 있는 성과측정 방안을 실 사례를 통해 제시하여 향후 유사 건설사업의 성과측정을 위한 방향을 제시하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.577-582
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• 2001

Identification of damage of structures has recently received considerable attention in the light of maintenance and safety assessment under service loads. In buildings, the current techniques of safety assessment largely depend on partial experiments such as visual inspection, destructive and nondestructive tests which lead to overconsumption of time and cost as well as higher labor intensity. Therefore, a new trial for safety assessment is urgently needed today. In this respect, the vibration characteristics of buildings have been applied steadily to obtain a damage index of the whole building, but it cannot be established as a practical method until now. This study is aimed at investigating the application of damage identification methods using vibration characteristics of building. Numerical tests are performed on a apartment building. From the test results, it is observed that severity and location of damage can be estimated with a relatively small error by using natural frequency and mode shape data.

• Geomechanics and Engineering
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• 제15권3호
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• pp.811-822
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• 2018

Chip size distribution can be used to evaluate the cutting efficiency and to characterize the cutting behavior of rock during cutting and fragmentation process. In this study, a series of linear cutting tests was performed to investigate the effect of cutting conditions (specifically cut spacing and penetration depth) on the production and size distribution of rock chips. Linyi sandstone from China was used in the linear cutting tests. After each run of linear cutting machine test, the rock chips were collected and their size distribution was analyzed using a sieving test and image processing. Image processing can rapidly and cost-effectively provide useful information of size distribution. Rosin-Rammer distribution pamameters, the coarseness index and the coefficients of uniformity and curvature were determined by image processing for different cutting conditions. The size of the rock chips was greatest at the optimum cut spacing, and the size distribution parameters were highly correlated with cutter forces and specific energy.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.65-70
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• 2001

Six recycling plants have started operation for recycling scrap home appliances since the spring of 2000 in Taiwan. The performance of the plants has not yet been measured during the 18-month period. The performance measurement, however, can be looked in several aspects. Because of the nature of these recycling plants, at least three aspects, namely government (representing general public), appliance manufacturers and owners of the recycling plants themselves should be considered in the performance evaluation. This study proposes various performance indices categorized in four groups: profitability, recyclability, automation and environment. The indices are different from the productivity and cost measures that are used in conventional manufacturing plants. Performances of three existing plants in Taiwan are evaluated as illustrative examples to demonstrate the use of the proposed measures. The practical implications of the performance indices are also discussed.

• Journal of the Optical Society of Korea
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• 제13권2호
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• pp.294-298
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• 2009

In this paper we proposed a new Bragg grating waveguide in order to improve reflectivity and to achieve compactness. Bragg gratings with various thicknesses were engraved in the middle of the core layer with a length of 3 mm. For the sake of cost-effectiveness, the $3^{rd}$ order Bragg grating waveguides were fabricated via conventional photolithography. The maximum reflectivities for the fixed width waveguide of $6{\mu}m$ with the 0.1 and $0.3{\mu}m$-thick Bragg gratings were, -13.14 and -6.25 dB, respectively, and the Bragg wavelengths were 1562.28, 1564.10 nm, respectively. A slight increase in the Bragg grating thickness can result in a remarkable reduction in the length of the Bragg grating waveguide with a fixed reflectivity.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 춘계학술대회 논문집
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• pp.380-384
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• 1992

The position control of a pneumatic cylinder suing low cost on-off valves is studied. The valve control band(VCB) was proposed toget fast response and toprevent solenoid valves from unnecessary switching at the beginning of response. A learning algorithm was used to compensate the nonlinearity and complexity in mathematical modelling of pheumatic on-off controlled positioning systems. In this algorithm, the desired performance index and modified learning rate, were proposed to improvespeed and convergence of learning control. It is shown experimentally that the proposed algorithm is robust to changes of system parameters: the setting time less than 1.0 sec and the error bound of .+-. 0.1 mm can be obtained. The effects of supply pressure, size of switching valves and the effect of multiple valves are discussed, and computer simulation onthe dynamic performances of the pneumatic system is also presented.

• 전기학회논문지
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• 제56권2호
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• pp.254-259
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• 2007

PM(Preventive Maintenance) can avail the generating unit to reduce cost and gain more profit in a competitive supply-side power market. So, it is necessary to perform reliability analysis on the power systems in which reliability is essential. Thus, to schedule optimal PM planning based on reliability that is defined RCM(Reliability-Centered Maintenance), FMECA(Failure Mode Effects and Criticality Analysis) assessment is very important. Therefore, in this paper, the procedure of FMECA assessment for optimal RCM is proposed by probabilistic approach using real historical failure data of combustion-turbine generators in Korean power systems. The stochastic FMECA is performed based on the effects of probable failure modes of combustion-turbine generating unit.

• Applied Science and Convergence Technology
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• 제24권2호
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• pp.41-46
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• 2015

Transparent conductive oxides (TCOs) are essential material in optoelectronics such as solar cells, touch screens and light emitting diodes. Particularly TCOs are attractive material for infrared cut off film due to their high transparency in the visible wavelength range and high infrared reflectivity. Among the TCO, Indium tin oxide has been widely used because of the high electrical conductivity and transparency in the visible wavelength region. But ITO has several limitations; expensive and low environmental stability. On the other hands, fluorine doped tin oxide (FTO) is well known for low cost, weather ability and stable in acidic and hydrogen. In this study, two different magnetron sputtering techniques with RF and DC modes at room temperature deposition of FTO thin film was conducted. The change of oxygen content is influence on the topography, transmittance and refractive index.

• 한국정밀공학회지
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• 제26권12호
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• pp.62-68
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• 2009

In this paper, we investigate a new method to measure the thickness of thin transparent objects utilizing a step index multi-mode optical fiber sensor. The method mainly depends on the refraction rate of transparent target, the diameter of optical fibers and the distance to reflector. We confirmed the effects of these parameters through the experimental verification tests. The comparison between the theoretical vs. analytical results shows good agreements with each other. The proposed model also enables users to measure the thickness of thin transparent objects without considering the reflection from the target. This approach provides simple, cost-effective and non-contact solutions to measure the thickness.