• Korean Journal of Plant Resources
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• v.7 no.2
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• pp.115-119
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• 1994

These experiments were conducted to determine the effects of Sorghum allelopathic substances on the callus growh of several weeds and crops. 1. When substances extracted from allelopathic Sorghum(Sorghum bicolor L.) were treated on medium, growth of callus of several weeds and crops were in-hibited. The degree of inhibition differed depending on the genotypes, ranging from 50 to 90% com-pared with that of control. 2. The extracts of above 5% Sorghum inhibited the callus growth of Che-nopodium albun L., Commelina communis L., and .Ammaranthus retroflexus L.and showed in-hibition rate of above 70% in callus growth. These results indicate that we could investigate theallelopaihy effect by using in vitro system. 3. The suitable explant for callus induction fromallelopathic plants was immature embryos, the callus induction rate differed depending on the geno-type, growth regulators and concentrations. In general, the addition of 2, 4-D and NAA onto medium increased the rate and amount of callus.

• The Journal of the Acoustical Society of Korea
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• v.14 no.1
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• pp.5-12
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• 1995

In the case where the set of training vectors constitute clusters, the codevectors of the codebook which is used to compression for speech and images in the vector quantization are regarded as the central vectors of the clusters constituted by given training vectors. In this work, we consider the distribution of Euclidean distance obtaining in the process of searching for the minimum distance between vectors, and propose the method searching for the proper number of and the central vectors of clusters. And then, the proposed method shows more than the about 4[dB] SNR than the LBG algorithm and the competitive learning algorithm

• Journal of the Korean Chemical Society
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• v.9 no.1
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• pp.45-48
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• 1965

Stability constant, composition of copper (II)-oxamidoxime complex were determined by spectrophotometric method. The ratio of copper (II) and oxamidoxime in the above complex was 1 : 1, and its stability constant was calculated to be $2.4{\times}10^{22}$. The complex solution gave constant absorbancy between the pH range of 4.5 to 6 at 600 $m{\mu}$ in which Beer's law applicable in the concentration range of 0.3 to 2.0 ppm studied in this work. It was noted that some metals such as Fe(III), Ni(II), Co(II), U(VI) interfere copper determination by this method.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1104-1113
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• 2010

In order to reduce negative skin friction uses bitumen most plentifully. But, Bitumen is expensive very of 1.5 or more times of pile material expense. The bitumen will be able to substitute it is nescessary. It was researched that it would be able to bitumen substitutions from in products which is produced from domestic in this study. This was composed with most bentonite, added some cement. When it is used this product in the model test, the reduction ratio appear of 85% or more. In this result, this product as the reduction material is confirmed that has enough ability. Additional research leads, the product according to pile construction method must verify the reduction effect of negativ skin friction in field test.

• Journal of Information Display
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• v.11 no.4
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• pp.160-164
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• 2010

Organic light-emitting devices (OLEDs) have shown superior characteristics and are expected to dominate the nextgeneration flat-panel displays. Active-matrix organic light-emitting diode (AMOLED) displays, however, have stringent demands on the performance of the backplane. In this paper, the development of thin-film transistors (TFTs) based on indium gallium zinc oxide (IGZO) on both Gen 1 and 6 glasses, and their decent characteristics, which meet the AMOLED requirements, are shown. Further, several display prototypes (e.g., 2.4" AMOLED, 2.4" transparent AMOLED, and 32" AMLCD) using IGZO TFTs are demonstrated to confirm that they can indeed be strong candidates for the next-generation TFT technology not only of AMOLED but also of AMLCD (active-matrix liquid crystal display).

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.576-578
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• 1989

This paper describes a new pwm scheme of variable speed control for induction motor. The proposed scheme have the programmed pwm switching pattern which have the doninant harmonic elimination over the wide range of output speed in induction motor. Experimental results of proposed scheme hare high quality output current, voltage and torque than that of conventional pwm scheme. Therefore proposed scheme have the smooth operation and suitable for variable speed control in induction motor.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.51 no.1
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• pp.18-25
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• 2002

The software reliability is defined, and not only the relations between testing time and reliability, but also the relation between duration following failure fixing and reliability are studied in this paper. The release time making the testing cost to be minimum is determined through evaluating the cost for each condition. Also, the release time is determined depending on the conditions of the first reliability, considering the specified reliability. the optimum release time is determined by simultaneously studying two optimum release time issues that determine both the cost related time and the specified reliability related time. And, each condition and limitation are studied. The trend of the optimum time is also examined.

• Proceedings of the KIEE Conference
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• 2000.11a
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• pp.165-167
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• 2000

This paper presents the influence of the lightning overvoltage and the shielding effects of overhead grounding wire on the DC railway system. Modeling of Railway system is established in ATPDraw to perform simulation. The result of simulation reveals that the shielding effects of overhead grounding wire has over 90% than the case which has not it. Therefore it is evaluated that overhead grounding wire should be installed in the DC railway line.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1500-1502
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• 1998

Electro Discharge Machining (EDM) is a so-call nonconventional machining technique. This paper presents the experimental results of an EDM technique for the fabircation of microholes on #7440 pyrex glass substrates. With various applied voltages and various concentration of NaOH or KOH solution, the glass substrates have been microdrilled using the copper electrodes of which diameters are 250 ${\mu}m$ to 450 ${\mu}m$. The machined throughholes have been observed the top diameter, the bottom diameter and machining time have been measured. EDM in NaOH solution causes the fabrication to have better the surface condition, higher selective of electrode, lower concentration of solution with respect to EDM in KOH solution machined fabrication.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2278-2280
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• 2004

이 논문은 이동식 수레형 도립진자 제어에 있어서 비선형적인 특성을 발생시키는 원인중의 하나인 마찰력을 보상하는 방법에 대하여 고찰한다. 여기에 사용된 방법은 모터에 전압을 인가하였을 때의 이동식 수레형 도립진자의 위치와 속도에 대한 데이터를 가지고, 가우시안 반복을 적용한 비선형 최소 자승법을 이용하여 마찰력을 추정하고, 모델링을 하여, 모델링 된 파라미터를 이용하여 비선형적인 특성을 최소화하는 것이다. 이 논문의 주된 결과는 수학적으로 모델링 한 마찰력이 실제의 마찰력과 유사하며, 이 마찰력을 보상함으로서, 이동식 수레형 도립진자의 제어 성능이 향상되었음을 보여준다. 따라서 이 결과는 기존의 마찰력을 무시하고, 이동식 수레형 도립진자를 제어하였을 때보다 마찰력을 보상하였을 때가 더욱 안정된 시스템이 됨을 실험적으로 확인한다.