• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1C
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• pp.45-49
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• 2004

An image enhancement method using modified anisotropic diffusion filter is proposed in this paper. It employs sensor noise estimation and scale space methods based on the minimum reliable scale. Then the anisotropic diffusion filter is modified by the calculated critical value function and local gradient. Through simulation, it is verified that the proposed algorithm has the capability of little or no noise amplification in homogenous region as well as superior edge enhancement.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.1
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• pp.7-12
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• 2001

본 노문은 임의형상의 퇴적층을 갖는 반부한 영역내에서 SH하가 경사지게 입사할 때의 지진응답을 연구하였다. 그리고 비균질 퇴적층인 반무한 영역에서 파의 증폭을 다루었다. 사용한 수치해석 방법으로는 유한요소법과 경계요소법을 결합하여 수치해석하였다. 반무한 영역에서 자유장 응답과 정해를 비교 분석한 결과 잘 일치하여 검증되었다. 불규칙한 형상의 비균질 퇴적층을 갖는 부지에서의 지진응답 해석은 본 연구에서 개발한 수치해석 방법으로 가능하다. 따라서 임의 층상구조를 갖는 연약층에서의 SH파 증폭과 임의 각도와 입사하는 SH파에 대한 지진응답을 해석하였다.

• Structural Engineering and Mechanics
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• v.17 no.5
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• pp.707-725
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• 2004

An optimal design method with nonlinear elastic analysis is presented. The proposed nonlinear elastic method overcomes the drawback of the conventional LRFD method that accounts for nonlinear effect by using the moment amplification factors of $B_1$ and $B_2$. The genetic algorithm used is a procedure based on Darwinian notions of survival of the fittest, where selection, crossover, and mutation operators are employed to look for high performance ones among sections in the database. They are satisfied with the constraint functions and give the lightest weight to the structure. The objective function taken is the total weight of the steel structure and the constraint functions are strength, serviceability, and ductility requirement. Case studies of a planar portal frame, a space two-story frame, and a three-dimensional steel arch bridge are presented.

• Journal of Radiation Protection and Research
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• v.21 no.2
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• pp.139-143
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• 1996

A multi-wire proportional counter with large sensitive area was designed and constructed considering diameter of anode wire. its material and space. A preamplifier connecting detector to main amplifier or counter was also designed and constructed for measurement output pulse from multi-wire proportional counter. The preamplifier was composed of charge-sensitive differential circuit. clipping circuit and amplification circuit. To test the performance of this equipment, terminal output pulse from the preamplifier was measured and compared with noise For these tests $^{239}Pu(360 Bq)\;and\; ^{90}Sr/^{90}Y(250 Bq)$ were used as radiation sources. The noise ingredient contributing to the maximum amplitude(180mV from $^{239}Pu$ and 200 mV from $^{90}Sr/^{90}Y$) was found to be very small(8 mV) Piled up pulse occurring at the output pulse of charge-sensitive differential circuit was measured as an independent pulse since this affected the amplification in the clipping circuit and amplification circuit. This information can be used to improve the loss of measurement due to piled up pulse.

• Progress in Medical Physics
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• v.19 no.3
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• pp.150-156
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• 2008

An applied technique of contrast enhancement for X-ray image is proposed which is based on combined enhancement of scaling and wavelet coefficients in discrete wavelet transform space. Conventional contrast enhancement methods such as contrast limited adaptive histogram equalization (CLAHE), multi-scale image contrast amplification (MUSICA) and gamma correction were applied on scaling coefficients to enhance the contrast of an original. In order to enhance the detail as well as reduce the blurring caused by up scaling of contrast modified scale coefficients from lower resolution, the sigmoid manipulation function was used to manipulate wavelet coefficients. The contrast detail mammography (CDMAM) phantom was imaged and processed to measure the image line profile of results and contrast to noise ratio (CNR) comparatively. The proposed technique produced better results than direct application of various contrast enhancement methods on image itself. The proposed method can enhance contrast, and also suppress the amplification of noise components in a single process. It could be useful for various applications in medical, industrial and graphical images where contrast and detail are of importance.

• Journal of Astronomy and Space Sciences
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• v.19 no.4
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• pp.273-282
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• 2002

We describe some performance of the detector electronics system for the FIMS (Far-ultraviolet Imaging Spectrograph) mission. The FIMS mission to map the far ultraviolet sky uses MCP (micro-channel plate) detectors with a crossed delay line anode to record photon arrival events. FIMS has two MCP detectors, each with a ~25mm$\times$25mm active area. The unconventional anode design allows for the use of a single set of position encoding electronics for both detector fields. The centroid position of the charge cloud, generated by the photon-stimulated MCP, is determined by measuring the arrival times at both ends of the anode following amplification and external delay. The temporal response of the detector electronics system determines the readout's positional resolution for the charge centroid. High temporal resolution (<$35{\times}75$ps FWHM) and low power consumption (< 6W) were achieved for the FIMS detector electronics system.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.371-384
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• 2021

Underground space, especially very-deep tunnel development in urban area, is a good alternative to solve the problem of insufficient ground space, and the need for underground space development is steadily increasing. However, due to the complex and time-consuming nature of design and construction, public conflicts related to the deep tunnel project are getting aggravating and more complex. In addition, since the public budget is mainly invested, when civil complaints arise, they often respond passively, resulting in amplification of conflicts or prolonging the deadlock in many cases. In this study, by analyzing the progress of major conflicts related to the construction of very-deep tunnels in urban area, the causes of conflicts, factors prolonging conflicts, and solutions are reviewed. Through a survey targeting ordinary citizens and tunnel experts, thoughts about the deep tunnel construction and major conflict factors were analyzed, and suggestions for minimizing conflicts were presented. The results of this study can be used to prepare alternatives such as various public involvement measures and improvement of project procedures to form a civic consensus on the construction of very-deep tunnels, and to prepare measures to improve prejudice against very-deep tunnels.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.81-88
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• 2000

The elastic wave equation is solved using the finite-difference method in 3D space to simulate the seismic wave propagation. It is based on the velocity-stress formulation of the equation of motion on a staggered grid. The nonreflecting boundary conditions are used to attenuate the wave field close to the numerical boundary. To satisfy the stress-free conditions at the free-surface boundary, a new formulation combining the zero-stress formalism with the vacuum one is applied. The effective media parameters are employed to satisfy the traction continuity condition across the media interface. With use of the moment-tensor components, the wide range of source mechanism parameters can be specified. The numerical experiments are carried out in order to test the applicability and accuracy of this scheme and to understand the fundamental features of the wave propagation under the generalized elastic media structure. Computational results show that the scheme is sufficiently accurate for modeling wave propagation in 3D elastic media and generates all the possible phases appropriately in under the given heterogeneous velocity structure. Also the characteristics of the ground motion in an sedimentary basin such as the amplification, trapping, and focusing of the elastic wave energy are well represented. These results demonstrate the use of this simulation method will be helpful for modeling the ground motion of seismological and engineering purpose like earthquake hazard assessment, seismic design, city planning, and etc..

• Journal of Microbiology and Biotechnology
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• v.17 no.1
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• pp.29-36
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• 2007

The xynA gene encoding the xylanase A of Paenibacillus sp. DG-22 was isolated with a DNA probe obtained by PCR amplification, using degenerated primers deduced from the amino acid residues of the known N-terminal region of the purified enzyme and the conserved region in the family 11 xylanases. The positive clones were screened on the LB agar plates supplemented with xylan, by the Congo-red staining method. The xynA gene consists of a 630-bp open reading frame encoding a protein of 210 amino acids, and the XynA preprotein contains a 28-residues signal peptide whose cleavage yields a l82-residues mature protein of a calculated molecular weight of 20,000Da and pI value of 8.77. The cloned DNA fragment also has another ORF of 873 nucleotides that showed 76% identity to the putative transcriptional activator of Bacillus halodurans C-125. Most of the xylanase activity was found in the periplasmic space of E. coli. The xynA gene was subcloned into pQE60 expression vector to fuse with six histidine-tag. The recombinant xylanase A was purified by heating and immobilized metal affinity chromatography. The optimum pH and temperature of the purified enzyme were 6.0 and $60^{\circ}C$, respectively. This histidine-tagged xylanase A was less thermostable than the native enzyme.

• Structural Engineering and Mechanics
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• v.44 no.5
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• pp.663-680
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• 2012

Previous major earthquakes revealed that most damage of the buried segmented pipelines occurs at the joints of the pipelines. It has been proven that the differential motions between the pipe segments are one of the primary reasons that results in the damage (Zerva et al. 1986, O'Roueke and Liu 1999). This paper studies the combined influences of ground motion spatial variations and local soil conditions on the seismic responses of buried segmented pipelines. The heterogeneous soil deposits surrounding the pipelines are assumed resting on an elastic half-space (base rock). The spatially varying base rock motions are modelled by the filtered Tajimi-Kanai power spectral density function and an empirical coherency loss function. Local site amplification effect is derived based on the one-dimensional wave propagation theory by assuming the base rock motions consist of out-of-plane SH wave or combined in-plane P and SV waves propagating into the site with an assumed incident angle. The differential axial and lateral displacements between the pipeline segments are stochastically formulated in the frequency domain. The influences of ground motion spatial variations, local soil conditions, wave incident angle and stiffness of the joint are investigated in detail. Numerical results show that ground motion spatial variations and local soil conditions can significantly influence the differential displacements between the pipeline segments.