• International Journal of Highway Engineering
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• v.11 no.2
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• pp.217-228
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• 2009

Sections under the influence of merging in an uninterrupted facility create irregular interaction between vehicles, such as lane change, speed acceleration and deceleration because of the merging of ramp traffic flows which have traffic characteristics different from those of the main line. This causes a confused traffic flow phenomenon(turbulence), which is considered an unstable traffic characteristic between various continuous points in consideration of v conditions. In this study, in merge influence sections, detectors by lane-point were installed to create time and space-series -traffic data. The least significant difference(LSD), as the criteria for discriminating a significant speed change between points, was calculated to examine the turbulence. As a result, turbulence in merge influence section was found to change the zones of such occurrence and the seriousness levels according to traffic condition. Thus, the maximum merge influence section due to the turbulence was created in the traffic condition before congestion when traffic increases. According to characteristics of changes in speed, merge influence section was divided into upstream 100m$\sim$downstream 100m(a section of speed reduction), and downstream 100m$\sim$downstream 400m(a section of reduced speed maintenance and acceleration).

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.5
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• pp.623-628
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• 2007

The accurate peak response estimation of a seismically excited structure with frictional damping system(FDS) is very difficult since the structure with FDS shows nonlinear behavior dependent on the structural period, loading characteristics, and relative magnitude between the frictional force and the excitation load. Previous studies have estimated that by replacing a nonlinear system with an equivalent linear one or by employing the response spectrum obtained based on nonlinear time history and statistical analysis. In the case that an earthquake load is defined with probabilistic characteristics, the corresponding response of the structure with FDS has probabilistic distribution. In this study, nonlinear time history analyses were performed for the structure with FDS subjected to artificial earthquake loads generated using Kanai-Tajimi filter. An equation for the probability density function (PDF) of the displacement response is proposed by adapting the PDF of the normal distribution. Finally, coefficients of the proposed PDF are obtained by regression analysis of the statistical distribution of the time history responses. Finally the correlation between PDFs and statistical response distribution is presented.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.1
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• pp.14-20
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• 2018

Lead zinc niobate (PZN) added lead zirconate titanate (PZT) thick films with thickness of $5{\sim}10{\mu}m$ were fabricated on silicon and sapphire substrates using aerosol deposition method. The contents of PZN were varied from 0 %, 20 % and 40 %. The initial particles (PZT, 2PZN-8PZT, 4PZN-6PZT) had irregular shape and submicron sizes. The as-deposited film had fairly dense microstructure without any crack, and showed only a perovskite single phase formed with nano-sized grains. The as-deposited films on silicon were annealed at the temperatures of $700^{\circ}C$, and the films deposited on sapphire were annealed at $900^{\circ}C$ in the electrical furnace. The effects of PZN addition on the microstructural evolution were observed using by FE-SEM and HR-TEM.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.3
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• pp.232-241
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• 2017

This study was carried out to design the stable elements of the aerial work machinery used in the orchard and farmland which had been conducted in the previous research. A hydraulic lifting lift has been developed to work safely at irregular and inclined locations using an auto leveling system and a horizontal sensor. The development of a centralized controller including remote control has been carried out in order to control the elevated work platform. Through the developed module, we carried out on-site test run to check whether the control is stable in the elevation workbench. Through the structural analysis of the elevation workbench, the maximum load and the equal load amount that the worker can safely work on the workbench are presented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.6
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• pp.997-1004
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• 2015

In this paper, we study vertical sectorization techniques in multiple-input single-output (MISO) downlink active antenna systems (AAS). In the AAS, antenna beam patterns can be adjusted in each sector and multiple vertical beams can form the vertical sectorization. Since an exhaustive search based vertical sectorization algorithm requires high computational complexity to find the optimal tilt angles, we propose two vertical sectorization algorithms to reduce the complexity. First, we provide an asymptotic sum rate based algorithm which utilizes a large system approximation of the average sum rate based on the random matrix theory. Next, by using the result in the single sector transmission, the single sector based algorithm is proposed. In the simulation results, we confirm that the proposed algorithms are close to the performance of the exhaustive search algorithm with much reduced complexity.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.5
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• pp.57-66
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• 1999

This paper describes a 12b, 50 Msample/s CMOS AID converter using an acquisition-time minimization technique for the high-speed sampling rate of 50 MHz level. The proposed ADC is implemented in a $0.35\mu\textrm{m}$ double-poly five-metal n-well CMOS technology and adopts a typical multi-step pipelined architecture to optimize sampling rate, resolution, and chip area. The speed limitation of conventional pipelined ADCs comes from the finite bandwidth and resulting speed of residue amplifiers. The proposed acquisition-time minimization technique reduces the acquisition time of residue amplifiers and makes the waveform of amplifier outputs smooth by controlling the operating current of residue amplifiers. The simulated power consumption of the proposed ADC is 197 mW at 3 V with a 50 MHz sampling rate. The chip size including pads is $3.2mm\times3.6mm$.

• Elastomers and Composites
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• v.34 no.4
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• pp.341-349
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• 1999

In this study, heat and crack resistance of natural rubber (NR) compounds was evaluated. To prevent the effects of the crosslinking system, a conventional vulcanization system was selected, where the accelerator/sulfur ratio was fixed to 0.25. Vulcanizates containing phenylenediamine showed high tensile strength and tear strength compared to other vulcanizates because phenylenediamine can cause additional crosslinking and high dispersion In the vulcanizates. In the pure shear test, vulcanizates containing phenylenediamine showed an excellent tearing energy which was due to the irregular crack path, and showed excellent heat and crack resistance which was also due to the good dispersity of antioxidant and additional crosslinks in the rubbber vulcanizates.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.2
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• pp.277-283
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• 2016

Recently, the interests in three-dimensional design and BIM(Building Information Modeling) are increasing in civil engineering sector and the researches about three-dimensional design and quantity take-off methods for civil engineering structures have been conducted. However, these studies are just carried out the 3D design and quantity calculation of civil structures on the road or railway such as bridges and tunnels. The study on the quantity take-off methods and the evaluation of calculated results on the earth works should be performed in more detail. Based on these backgrounds in mind, the study was conducted the three-dimensional road design and evaluated the quantity take-off results on the earth works using 3D calculation method(average end area method, prismoidal method and composit method). The calculated quantity from composit method showed about 5% error of measuring efficiency than the average end area method, and when reporting the quantity calculation of earth works, it is necessary to specify the calculation method using quantity take-off of earth works.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.12
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• pp.560-567
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• 2008

In this paper, we discuss a simple and straightforward binarization procedure which can generate black/white comics from the video frame image. Generally, the region of human's skin is colored white or light gray, while the dark region is filled with the irregular but regular patterns like hatching in most of the black/white comics. Note that it is not enough for simple threshold method to perform this work. Our procedure is decoupled into four processes. First, we use bilateral filter to suppress noise color variation and reserve boundaries. Then, we perform mean-shift segmentation for each similar colored pixels to be clustered. Third, the clustered regions are merged and extended by our region extension algorithm considering each color of their regions. Finally, we decide which pixels are on or off using by our dynamic binarization method based on the HSV color model. Our novel black/white cartooning procedure was so successful to render comic cuts from a well-known cinema in a resonable time and manual intervention.

• Restorative Dentistry and Endodontics
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• v.25 no.4
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• pp.494-498
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• 2000

이 연구의 목적은 'Three-File' 방식에 의한 근관형성시 근관의 형태변화 및 전이정도를 분석하고 이를 기존의 근관형성방법과 비교하고자 하는 것이다. 만곡된 근관을 가진 투명한 레진블럭 상에서 'Three-File' 방식, crown-down방식 및 스테인레스강 화일에 의한 수동방식으로 근관형성을 시행하고 이를 똑같은 위치가 재현가능한 고정틀에 위치시킨 후 사진의 이중노출 기법을 이용하여 근관형성 전후의 근관의 형태변화 및 전이정도를 분석한 결과 다음과 같은 결과를 얻었다. 1. 스테인레스강 화일의 경우 근관확대가 가장 컸고 근관의 전이정도도 심하였으며, 형성된 근관이 taper하지 못하고 불규칙한 형태를 보였다. 2. Profile로 crown-down방식에 의해 형성한 경우 taper한 근관형태를 보였고, 근관의 전이 정도도 스테인레스강 화일의 경우보다 작았다(p<0.01). 3. Profile로 'Three-File'방식에 의해 형성한 경우 taper한 근관형태를 보였고 근관의 전이정도도 스테인레스강 화일의 경우보다 유의하게 작았으나(p<0.01), crown-down방식에 의해 형성한 경우와 유의할 만한 차이는 없었다(p>0.01).