• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2003.04a
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• pp.3-8
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• 2003

모든 SAR 영상에는 전자기파 간의 간섭으로 인한 스페클 잡영(speckle)이 존재하며, 이를 제거하는 것은 양질의 SAR 영상을 얻기 위한 필수적인 전처리 과정 중 하나라고 할 수 있다. 그러나 이러한 스페클 잡영을 제거하기 위하여 기존에 제안되었던 알고리즘은 잡영은 효과적으로 감소시키는 반면 경계선과 같은 영상의 고유 정보까지 함께 감소시키는 한계가 있었다. 따라서 본 연구에서는 SAR 영상의 경계선은 보존시키면서 영상으로부터 불필요한 잡영을 제거할 수 있는 알고리즘을 구현하고, 기존의 알고리즘과 비교하여 그 효율성을 평가하고자 한다. 영상의 통계적 특성에 근거하는 기존의 알고리즘과는 달리 웨이블렛 변환(Wavelet transform)으로 경계선 및 특징 정보의 여부를 판별한 후 평균 필터(mean filter)를 적용하는 경계선 보존(edge sharpening) 알고리즘은 경계 정보의 신뢰성을 향상시킬 수 있으며, 1차원 필터를 수평, 수직, 대각선, 역대각선 방향으로 적용함으로써 하나의 영상소를 중심으로 모든 방향에 대한 경계선 여부를 확인할 수 있는 장점이 있다. 본 연구에서는 512 × 512로 절취한 1-look SAR 영상에 대하여 창 크기 5 × 5의 경계선 보존 필터를 적용하고 동일영상에 대하여 기존의 Lee, Kuan, Frost 필터 등의 실험결과를 비교함으로써 그 적합성을 판단하고자 하였다. 실험결과에 대한 수치적인 평가는 ①정규화 평균을 이용하여 평균값의 보존 여부, ②편차 계수를 이용한 스페클 잡영의 제거 여부, ③경계선 보존지수(EPI)를 이용한 경계선의 보존 정도를 통해 이루어졌다. 본 연구의 실험결과를 통해 경계선 보존 필터는 평균값의 보존 여부 및 스페클 잡영 제거 정도에 있어 다른 필터들과 큰 차이가 없지만 경계선보존지수는 다른 필터들에 비하여 가장 우수함을 확인할 수 있었다.rbon 탐식효율을 조사한 결과 B, D 및 E 분획에서 유의적인 효과를 나타내었다. 이상의 결과를 종합해볼 때, ${\beta}$-glucan은 고용량일 때 직접적으로 또는 $IFN-{\gamma}$ 존재시에는 저용량에서도 복강 큰 포식세로를 활성화시킬 뿐 아니라, 탐식효율도 높임으로써 면역기능을 증진 시키는 것으로 나타났고, 그 효과는 crude ${\beta}$-glucan의 추출조건에 따라 달라지는 것을 알 수 있었다.eveloped. Design concepts and control methods of a new crane will be introduced in this paper.and momentum balance was applied to the fluid field of bundle. while the movement of′ individual material was taken into account. The constitutive model relating the surface force and the deformation of bundle was introduced by considering a representative prodedure that stands for the bundle movement. Then a fundamental equations system could be simplified considering a steady state of the process. On the basis of the simplified model, the simulation was performed and the results could be confirmed by the experiments under various conditions.뢰, 결속 등 다차원

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.806-816
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• 2017

This study aims to offer effective policies for managing local temperatures and reducing the heat island effect by identifying elements that affect local temperatures. The three elements of natural environment, land use, and land coverage were first selected, and then control factors were applied, including season, weather, and measurement units for wind speed. In order to analyze these factors' relations to summer temperatures, an integrated model was developed, and an analysis was conducted of the urban heat island reduction effect of elements impacting local temperatures. The analysis used nationwide weather system (AWS) data from July and August 2007 and 2011-2016, land coverage data provided by the Ministry of Environment, and land use area data from local governments after rearranging them based upon their falling within a 500-meter radius ($0.79km^2$) of AWS measuring points. The study results show that the natural environment, land use, and land coverage all have a relation to changes in local temperatures. Natural elements have the greatest impact, and land use has the lowest. The results could provide basic data for establishing more effective policies to mitigate the heat island effect and strategies for enhancing the sustainability of cities.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.5
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• pp.50-60
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• 2010

For the last half a century, the personal computer and software industries have been prosperous due to the incessant evolution of computer systems. In the 21st century, the embedded system market has greatly increased as the market shifted to the mobile gadget field. While a lot of multimedia gadgets such as mobile phone, navigation system, PMP, etc. are pouring into the market, most industrial control systems still rely on 8-bit micro-controllers and simple application software techniques. Unfortunately, the technological barrier which requires additional investment and higher quality manpower to overcome, and the business risks which come from the uncertainty of the market growth and the competitiveness of the resulting products have prevented the companies in the industry from taking advantage of such fancy technologies. However, high performance, low-power and low-cost hardware and software platforms will enable their high-technology products to be developed and recognized by potential clients in the future. This paper presents such a platform for industrial embedded systems. The platform was designed based on Telechips TCC8300 multimedia processor which embedded a variety of parallel hardware for the implementation of multimedia functions. And open-source Embedded Linux, TinyX and GTK+ are used for implementation of GUI to minimize technology costs. In order to estimate the expected performance and power consumption, the performance improvement and the power consumption due to each of enabled hardware sub-systems including YUV2RGB frame converter are measured. An analytic model was devised to check the feasibility of a new application and trade off its performance and power consumption. The validity of the model has been confirmed by implementing a real target system. The cost can be further mitigated by using the hardware parts which are being used for mass production products mostly in the cell-phone market.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3A
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• pp.163-172
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• 2011

The CFTA girder developed is a concrete filled steel tubular system with arched shape and external post-tensioning (PT) tendons which control the initial camber and the bending stress of the girder. In the present study the effects of the PT tendons on the dynamic behavior of the girder subjected to a moving vehicle load are numerically investigated. Various levels for the tendon quantity and the tendon forces are considered, using the existing FE model of the girder. The vehicle considered is a DB-24 truck and is modeled with two tracks-three axles. Equivalent-load pulse time histories are applied to each node to simulate the moving vehicle, depending on the time of arrival and the discretization. The vehicle speeds are varied from 40 km/hr to 100 km/hr with increment of 20 km/hr. The analysis results show that the tendon forces do not produce any influences on the dynamic responses of the girder. However the dymamic deflection of the girder increases when a smaller amount of tendons is used. The Dynamic Amplification Factors (DAF) are evaluated based on the static and dynamic responses. Much lower values of the DAF are obtained, even no tendons applied, than those provided by the design criteria of the AASHTO LRFD and the Korea Highway Standard Specification.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.875-888
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• 2013

The researches have recently progressed toward the use of the superelastic shape memory alloys (SMAs) to develop new smart control systems that reduce permanent deformation occurring due to severe earthquake events and that automatically recover original configuration. The superelastic SMA materials are unique metallic alloys that can return to undeformed shape without additional heat treatments only after the removal of applied loads. Once the superelastic SMA materials are thus installed at the place where large deformations are likely to intensively occur, the structural system can make the best use of recentering capabilities. Therefore, this study is intended to propose new buckling-restrained braced frames (BRBFs) with superelastic SMA bracing systems. In order to verify the performance of such bracing systems, 6-story braced frame buildings were designed in accordance with the current design specifications and then nonlinear dynamic analyses were performed at 2D frame model by using seismic hazard ground motions. Based on the analysis results, BRBFs with innovative SMA bracing systems are compared to those with conventional steel bracing systems in terms of peak and residual inter-story drifts. Finally, the analysis results show that new SMA bracing systems are very effective to reduce the residual inter-story drifts.

• Korean Journal of Plant Resources
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• v.27 no.5
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• pp.546-555
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• 2014

The final aim of this study is to develop a biofiltration system integrated with plant vegetation for improving indoor air quality effectively depending on indoor space and characteristics. However, to approach this final goal, several requirements such as constant pressure drops (PDs) and soil moisture contents (SMCs), which influence the capacity design for a proper ventilation rate of biofiltration system, should be satisfied. Thus, this fundamental experiment was carried out to adjust a proper wind speed and to ensure a stabilization of initial SMCs within biofilter for uniform distribution of SMCs and PDs, and for normal plant growth, especially avoiding root stress by wind. Therefore, we designed horizontal biofliter models and manufactured them, and then calculated the ventilation rate, air residence time, and air-liquid ration based on the biofilter depending on three levels of wind speed (1, 2, and $3cm{\cdot}s^{-1}$). The relative humidity (RH) and PD of the humidified air coming out through the soil within the biofilter, and SMC of the soil and plant growth parameters of lettuce and duffy fern grown within biofilter were measured depending on the three levels of wind speed. As a result of wind speed test, $3{\cdot}sec^{-1}$ was suitable to keep up a proper RH, SMC, and plant growth. Thus, the next experiment was set up to be two levels of initial SMCs (low and high initial SMC, 18.5 and 28.7%) within each biofilter operated and a non-biofiltered control (initial SMC, 29.7%) on the same wind speed ($3cm{\cdot}sec^{-1}$), and measured on the RH and PD of the air coming out through the soil within the biofilter, and SMC of the soil and plant growth parameters of Humata tyermani grown within biofilter. This result was similar to the first results on RHs, SMCs, and PDs keeping up with constant levels, and three SMCs did not show any significant difference on plant growth parameters. However, two biofiltered SMCs enhanced dry weights of the plants slightly than non-biofiltered SMC. Thus, the stability of this biofiler system keeping up major physical factors (SMC and PD) deserved to be adopted for designing an advanced integrated biofilter model in the near future.