• Explosives and Blasting
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• v.33 no.1
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• pp.1-12
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• 2015

In this study, the domestic bench blasting sites were researched to set the blast coefficient C according to the type of rock and type of industry. With the use of the experimental data on the representative industrial explosives and the data of the manufacturers'data on explosives, powder coefficient e was set up. The blast coefficient C was 0.21~0.30 when the average value for 5 representative kinds of rocks including granite was searched. The blast coefficient C for quarrying, mining and construction sites were 0.22, 0.13 and 0.26 respectively. On the other hand, powder coefficient e was obtained in four elements such as reactive energy, ballistic mortar test, VOD, Langefors'strength per unit weight. e value for emulsion which is one of the representative explosives was found to be 1 while those of high performance emulsion and ANFO were found to be 0.9 and 1, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1444-1451
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• 2009

This paper first proposes diverse C determining models in the Q algorithm which is proposed in the EPCglobal C1 Gen 2 standard and then compares and analyzes its performance. EPCglobal C1 Gen 2 standard proposes the slot-count (Q) selection algorithm for multiple tag identification environment, but there is no such definition for the C value which modifies the Q value depending on collision or no reply. During the tag anti-collision process, the Q algorithm adds C to the Q when there is a collision and reduces the Q by C when there is no reply. The modified Q value updates new slot-counts for tags which determines the tag identification speed, so the C value is an important factor. However, many researches only intend to increase the tag identification speed by proposing a new method or modifying the Q algorithm without any research about the C value. This paper suggests diverse C models which satisfies the EPCglobal C1 Gen 2 and analyzes their performance in the multi tag identification environment. The result of this paper can be used as an index for future researches on EPCglobal C1 Gen 2 C models and multiple tag identification performance.

• Journal of the Korean Geotechnical Society
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• v.17 no.2
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• pp.73-83
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• 2001

본 연구에서는 전국 4개 지구의 화강암 풍화토를 연구대상으로 현장 및 실내시험을 수행하고 토량 변화율을 노상과 노체에 대하여 결정하였다. 그리고, 본 연구에서는 인공 신경망 중 오류 역전파 학습 알고리즘을 도입하여 토량 변화율 C 값을 추정하고 신경망의 적용성에 대한 검증을 수행하였다. 화강암 풍화토에 대한 실내 및 현장시험 결과에서 얻어진 토량 변화율 C 값은 노상과 노체 구분 없이 최소 0.7에서 최대 1.2정도의 넓은 범위로 나타났다. 토지공사에서 제안하는 C값의 산정식과 본 연구 결과를 비교한 결과, 토지공사의 산정식에 의한 결과가 과대 평가될 가능성이 큰 것으로 나타났다. 비중, 자연 함수비, 자연상태의 습윤단위중량, #200 통과율 그리고 균등계수의 입력변수를 갖는 $I_{5-1}$$H_{30-30}$$O_1$의 신경망에서 다른 신경망 구조들보다 잦은 지역 최소점에 수렴하는 결과를 보였다. 본 연구에서 사용한 모든 신경망 구조에서 시험결과와 신경망 결과의 상관계수는 0.9이상으로 나타나 높은 상관성을 나타내었다. 특히, 인공 신경망에 의한 예측결과는 다양한 영향인자들 중에서 비중, 자연 함수비, 자연상태의 습윤단위중량 그리고 #200 통과율의 4개 변수만으로도 C값을 예측할 수 있었으며, 상관계수는 0.96으로 나타났다.다.

• Journal of the Korean Geotechnical Society
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• v.31 no.7
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• pp.5-12
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• 2015

In this study, the deposition of dredged soils from domestic rivers is simulated in the laboratory using a small soil box. In the tests, small sand with 0.002-0.85 mm, large sand with 0.85-2 mm, and gravel 4.75-5.6 mm are air or water-pluviated into the box. Such various deposition processes are simulated and their dry densities are measured. While dredging or piling such soils, their volume may change. The loss of such soils is calculated by a soil conversion factor C. The C value was determined as 0.91 for small sand, 0.96 for large sand, and 0.91 for gravel. The drainage through soil piles may occur and result in effective stress increase. This may cause the volume change of soils and in order to consider such effect it is necessary to recalculate C values. As a result, dry density increased by 5-12% when the drainage effect is considered. When the drainage effect is considered, the value of soil conversion factor C was 0.81 for small sand, 0.92 for large sand, and 0.82 for gravel. Eventually, the C value decreased up to 4-12%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.67-73
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• 2016

Recently, wireless power transmission has attracted much interest and is the subject of much research in industry and academia. As its name implies, it is a technology which involves transferring power without wires. This paper presents the design of an ICT-based wireless power transmission system. The proposed system consists of a wireless transceiver unit and high-efficiency coil unit, which can increase both the transmission efficiency and the effective power distance. In particular, the wireless transceiver unit was designed to work with the ICT technique to enable real-time remote monitoring. Also, studies were done relating to the effect of reducing the standby power. The optimal frequency of IGBT devices used in industrial wireless power systems of 20[KHz] was utilized. The values of $23.9[{\mu}H]$ and $2.64[{\mu}F]$ were selected for L and C, respectively, through many field experiments designed to optimize the system design. In addition, an output current controlling algorithm was developed for the purpose of reducing the standby power. The results presented in this paper represent a 75[%] to 85[%] higher power transmission efficiency with a 10[%] increase in the effective power transmission distance compared with the existing systems. As a result, the proposed system exhibits a lower standby power and maintenance costs. Also, the designed wireless transceiver unit facilitates fault detection by means of user acquired data with the development of the ICT applied program.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.62-64
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• 1999

전자식안정기 설계에 있어서 중요한 램프의 모델링의 연구이며 이 모델은 기존의 방식에서 요구되는 많은 측정값에 의한 방식과는 달리 2개의 파라메터에 의해 결정되는 장점이 있다. 또한 DSPICE로 구현이 용이하므로 시뮬레이션을 통해서 안정기 회로의 L, C값의 초기값을 선택하는데 유용한 방법이 될 수 있다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5C
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• pp.193-198
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• 2012

Field and laboratory tests were performed to investigate the swelling(L value) and shrinkage modulus (C value) of soil and rock mixtures using 2 sites. According to test results, when disturbed soil and rock were mixed with same amount (5:5), the maximum density was achieved and showed 19% and 18% increased at each site comparing with the unit weight of rock only. Since measured L values of mixtures were overestimated about 4 to 11% compare to estimated values based on the conventional method. While C values were underestimated about 13~20% compare to conventional values due to the development of compacting equipments and effective construction management. When rock and soil were mixed in the ratio of 5 to 5, the unit weight of the mixture was higher than that of other mixtures and rock or soil only.

• The Transactions of the Korea Information Processing Society
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• v.4 no.2
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• pp.596-605
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• 1997

The synamic systrm emplohing the self-squared function, , $f(Z)=z^2+c$, provides the Mandelbrot set which classifies constants c using the divergence of the sequence starting from the origin.To speed-up the generation of Mandelbrot set images, two approaches , called as the divide-and-conquer technique and the triangular boundary tracing technique, have been developed.However , the divede-and-conquer technique genrates sequences of some pixels that so not affect graphical representations of the Mandelbrot set.The triangular boundary tracing tech-mique does noot represent some 8-connected components of the Mandelbrost set.In this paper, we prorose a new ;method which solves the 8-connectivity problem of triangular boundary tracing technique.This algorithm considers the divergence for only pixels which are essential to the graphical repressentation of the Mandelbrot set.It also foves good representations for 8-connected components like hairly structures.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.5
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• pp.1133-1138
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• 2010

In the anti-collision scheme proposed by EPCglobal Class-1 Gen-2 standard, the frame size for a query round is determined by Q-algorithm. In the Q-algorithm, the reader calculates a frame size without estimating the number of tags in it's identification range. It uses only the slot status. Therefore, Q-algorithm has advantage that the reader's algorithm is simpler than other algorithms. However, it cannot allocate an optimized frame size because it does not consider the number of tags. Also, the conventional Q-algorithm does not define an optimized parameter value C for adjusting the frame size. In this paper, we propose a modified Q-algorithm and evaluate the performance with computer simulations. The proposed Q-algorithm estimates the number of tags at every query round, and determines the parameter value C based on the estimated number of tags.

• Journal of Astronomy and Space Sciences
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• v.5 no.1
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• pp.73-79
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• 1988

New differential photoelectric observations in UBV system of the W UMa-type eclipsing binary SW Lac presented. The data were obtained on 4 nights from October in 1987 using the 61cm reflector at Sobaeksan Astronomical Observatory. These light curves are compared with recent published light curves in order to check the light curve variations and magnitude difference of minimum light phases. Four times of minimum light are deduced and the orbital period variation of SW Lac has been discussed.