• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.1
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• pp.77-86
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• 2004

This paper introduces a shape memory alloy-restrainer-damper(SMA-RD) to protect multiple span continuous steel bridges from seismic loads. The type of bridges has only one fixed bearing condition on a pier and expansion bearings are located on the other piers and abutments. Due to this state and a big mass of the deck, these bridges are usually very vulnerable to column's damage on which fixed bearings are located and large deformation of abutments in passive action. Two types of SMA-RDs are developed, and their effect is inspected for protecting the bridges through seismic analyses. Conventional steel restrainer cables are also used to reduce the seismic vulnerability of the bridge and the results are compared to those of the SMA-RDs.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.6
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• pp.743-748
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• 2009

In this paper, we propose an effective method to extract background components in automated vision inspection system for polarized film used in TFT LCD display panels. The test image signals are typically composed of three components such as ununiform background, random noises and target defect signals. It is important to analyze the background signal for accurate extraction of defect components. Two dimensional continuous wavelets with first derivative gaussian is used. This methods can be applied for reliable extraction of defect signal by elimination of the background signal from the original image. The proposed method outperforms over conventional FFT methods.

• The KIPS Transactions:PartB
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• v.8B no.6
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• pp.705-717
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• 2001

In this paper, we propose a rapid lane detection method to extract a preceding vehicle from sequential images captured by a single monocular CCD camera. We detect positions of lanes for an individual image within the limited area that would not be hidden and thereby compute the slopes of the detected lanes. Then we find a search area where vehicles would exist and extract the position of the preceding vehicle within the area with edge component by applying a structured method. To verify the effects of the proposed method, we capture the road images with a notebook PC and a CCD camera for PC and present the results such as processing time for lane detection, accuracy and vehicles detection against the images.

• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.278-285
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• 2005

In the present work, a reaction of sulfur removal and simulation of desulfurization based on the grain model and two-phase theory were studied using natural manganese ore (NMO) as a sorbent in a continuous fluidized bed reactor. The effect of desulfurization was investigated through the grain model considered the change of pore structure as a function of desulfurization time, particle size of NMO, and diffusion velocity of $SO_2$ in the pores. Among these parameters, the diffusion of $SO_2$ in the pores of NMO was the most important factor. Moreover, the reaction of sulfur removal and desulfurization in a continuous fluidized bed reactor using NMO as a sorbent could be well predict through the grain model and two-phase theory, respectively.

• Proceedings of the KSRS Conference
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• 2009.03a
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• pp.213-218
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• 2009

에너지 전달 과정과 밀접한 관계가 있는 증발산(Evapotranspiration)은 기후 변화나 육상 생태계 생산성에서 매우 중요한 요소이며, 수문학적 순환과 지역적 물 관리 측면에서 매우 중요하다. 최근 인공위성을 이용하여 증발산을 추정하기 위한 노력이 많이 진행되고 있으며, 특히 MODIS (Moderate Resolution Imaging Spectroradiometer)는 증발산을 추정하기 위한 좋은 정보를 제공하고 있다 하지만, 구름 등에 의한 증발산 입력 자료 결측은 전체 자료의 획득률을 낮추고, 연속적인 증발산 모니터 링을 제한한다. 따라서 본 연구에서는 MODIS 기반의 증발산 입력 자료의 개선하여 서로 다른 식생과 지형 구조를 갖는 플럭스 연구지에 대한 증발산의 추정 및 평가하고, 남한에 대한 MODIS 기반의 증발산 지도 작성하였다. 또한 구름에 의해 결측된 날에 대해서는 MODIS-MM5 4차원 자료동화 기법을 이용한 증발산의 연속적인 모니터링 기법을 개발하였다. MODIS 기반의 증발산을 추정하기 위해 Revised RS-PM 알고리즘을 사용하였다. 증발산을 평가하기 위해 4 곳의 플럭스 연구지(광릉, 해남 이상 대한민국, 타카야마, 토마코아미 이상 일본) 자료와 비교하였고, 매우 신뢰성 있는 결과를 얻을 수 있었다. MODIS 입력 자료의 개선으로 획득률은 2배 가량 증가하였다. 남한에 대한 연간 증발산은 평균적으로 약 35%의 획득률 (365일 중 약 120일)과 함께 산출되었고, 시 공간적인 분포를 잘 나타내었다. 구름 낀 날에 대한 MODIS-MM5 자료 동화 기법의 적용은 증발산의 연속적인 모니터링을 가능하게 하였다.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.4
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• pp.36-42
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• 2021

In this study, the impregnation of Lyocell fabrics was performed using phosphoric acid, ammonium phosphate, diammonium hydrogen, triammonium phosphate as phosphorus flame retardant, to fabricate continuous graphite fabrics using lyocell fiber. The physical and chemical structure changes were investigated by thermogravimetric, Fourier-transform infrared spectroscopy, C-nuclear magnetic resonance, X-ray diffraction, and weight analyses, By analyzing the thermal behavior of phosphorus flame retardant, conditions for the temperature, gas, and residual time of the pyrolysis process were set. Graphite fabrics with a tensile strength of 1,007.19±11.47 N/5 cm and yield of 25.3% were fabricated using continuous pyrolysis, carbonization and graphitization process.

• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.89-98
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• 2010

In the heterogeneous system of various wired or wireless network with IP-based backbone, the continuities of agreedon QoS for multimedia services should be guaranteed regardless of network types and terminal mobility through seamless vertical handover. This paper proposes a QoS provisioning mechanism called D-ISHO which guarantees the continuities of agreed-on QoS and seamless for multimedia services by considering both such characteristics as delay, loss rate and jitter per each service and such status as available band-width, call arrival rate and data transmission rate during the vertical handover. Simulation is done for performance analysis with the measure of handover failure rate and packet loss rate.

• Journal of Korean Association for Spatial Structures
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• v.6 no.4 s.22
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• pp.35-44
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• 2006

The form-resistant Systems like a dome and shell are used more widely than post-beam structure system in large space structure. Single layer latticed dome system, one of the form-resistant system, has great merits in manufacturing and constructing but the failure mechanism is not clarified yet. The purpose of this paper is to find out the buckling characteristics of single-layer latticed domes with square network by using the experimental method. Major test parameters are the stiffness of lattice member and space of square lattice. The specimens are applied uniform loading of snow type.

• 한국지구물리탐사학회:학술대회논문집
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• 2006.06a
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• pp.117-122
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• 2006

In the geophysical monitoring to understand the change of subsurface material properties with time, the time-invariant static subsurface model is commonly adopted to reconstruct a time-lapse image. This assumption of static model, however, can be invalid particularly when fluid migrates very quickly in highly permeable medium in the brine injection experiment. In such case, the resultant subsurface images may be severely distorted. In order to alleviate this problem, we develop a new least-squares inversion algorithm under the assumption that the subsurface model will change continuously in time. Instead of sampling a time-space model into numerous space models with a regular time interval, a few reference models in space domain at different times pre-selected are used to describe the subsurface structure continuously changing in time; the material property at a certain space coordinate are assumed to change linearly in time. Consequently, finding a space-time model can be simplified into obtaining several reference space models. In order to stabilize iterative inversion and to calculate meaningful subsurface images varying with time, the regularization along time axis is introduced assuming that the subsurface model will not change significantly during the data acquisition. The performance of the proposed algorithm is demonstrated by the numerical experiments using the synthetic data of crosshole dc resistivity tomography.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.4
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• pp.413-419
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• 2011

The nano-size hoenycomb structures have the higher ratio of the surface to the volume than macro-size honeycomb structures, and they can maximize the functionality of the electrical and chemical catalyst. The mechanical behaviors of the nano-sized structures are different from ones of the macro-size structure, and it is caused by the surface effect. This surface effect can be investigated by the atomistic simulation; however, the prediction of mechanical behaviors of the nano-sized honeycombs are practically impossible due to excessive computational resources and computation time. In this paper, by combining the bridging method considering the surface stress elasticity model with homogenization method, the mechanical behaviors of the nano-sized honeycombs are predicted efficiently.