• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.12 no.2
• /
• pp.142-149
• /
• 2019

The coils to transmit the electric energy are necessary to charge an electric vehicle wirelessly. There are several types of coils, from basic circular coils to DD-type coils for enhancing the coupling effect between two coils. However, DD-type coils with a good coupling effect between coils have a disadvantage in use because of the structure complexity of the power conversion device of transmitting and receiving side. In this paper, we propose a method to calculate the inductance value and to design the size of the spiral inductor which is convenient to fabricate when the power is transmitted wirelessly by using two coils in free space. Since the bifurcation phenomenon occurs when the XLm value is similar to the load resistance value in the resonator the XLm value was selected to be equal to the minimum load resistance value to minimize this phenomenon, and the inductance value required for the resonator was calculated. In order to realize the calculated inductance value by the spiral inductor, the relationship between the inductance value and the size, the number of turns, the total coil length of a spiral inductor was investigated. In addition, the change of coupling coefficient k according to the horizontal separation of two coils was examined and an appropriate inductor was selected.

• Journal of the Institute of Convergence Signal Processing
• /
• v.22 no.4
• /
• pp.213-219
• /
• 2021

The submarine's intercept pulse detection detects pulses radiated from enemy surface ships, submarines, and torpedoes, and performs an important function of providing maneuverability and survivability of submarine. Whether or not the intercept pulse is detected is determined by comparing the size of the received pulse with the threshold value by the operator. In the case of intercept pulses, the intensity of the pulses is frequently reduced under the influence of various environmental factors. In the situation, if detection is performed with a fixed threshold, a non-detection problem occurs and persists until the operator sets a low threshold. In this paper, we proposed method for automatically adjusting threshold to reduce the non-detection problem caused by a fixed threshold. Simulation were preformed on 4 cases with different pulse level fluctuation widths, and it was confirmed that the detection performance was improved by increasing the number of detections when a method for automatically adjusting threshold was applied to all cases. Through the proposed method, it is expected that the intercept pulse detection performance will be improved in the marine environment the large fluctuations in pulse level in the future.

• The Journal of Information Technology
• /
• v.4 no.1
• /
• pp.55-69
• /
• 2001

TradeCard is a B2B (business-to-business) e-commerce infrastructure that enables buyers and sellers to conduct and settle international trade transactions securely over the Internet. and objective of TradeCard is to provide a secure, reliable, cost-effective and user-friendly solution for conducting and settling international trade transactions. This paper analyzes the reviews of TradeCard by Electronic Message and the various problems which come to application of TradeCard, with particular attention to existing international frameworks for payment systems based on Documentary Credit.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1724-1726
• /
• 2008

본 연구는 릴레이의 코일 접점 신호의 검출을 송신기에서 코일의 데이터를 검출하고 4-20mA데이터를 1/5,000까지의 분해능으로 환산하되 블루투스를 이용한 무선통신으로 전송할 수 있도록 하여 송신기의 각 코일에서 검출된 데이터 값을 인디케이터에 전송하고 다시 릴레이 코일 신호로 만들어 표시하고 제어하도록 한 것이다. 데이터의 전송은 1Port 에서 10 Port까지 릴레이 코일 및 4-20mA 물리량을 이용하여 검출대상의 접점 리액턴스를 각각 측정하여 블루투스를 이용한 무선통신 데이터 값을 송신하는 코일의 접점 송신수단과 상기 릴레이 접점 송신수단으로부터 전송된 데이터 값을 블루투스를 이용하여 무선통신으로 수신한 후, 상기 릴레이 접점에서 전송된 각각의 데이터 값과 전체 물리량으로 연산 처리된 데이터 값을 디스플레이 하고, 데이터의 디스플레이된 값을 통해 리액턴스 출력, 경보음출력, RS232, 4-20mA 출력이 발생되게 하는 인디케이터로 구성하는 블루투스를 이용한 10 Port 코일 리프트 제어 콘트롤러이다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.12
• /
• pp.294-302
• /
• 2018

To analyze the behavior of a soil beam under pore water pressure, the results of analytical solutions and finite element analysis (FEM) were compared quantitatively. In contrast to the results of the analytical solution, the horizontal stress obtained from the FEM did not show a symmetrical distribution. On the other hand, the horizontal stress became closer to symmetrical distribution as the number of elements of the soil beam were increased. A comparison of the horizontal stresses from the analytic solution with those obtained from Gaussian points of FEM showed that the magnitude of the tensile stress from the FEM using 3 elements was 6% of the maximum value of the analytical solution and the compressive stress from the FEM using the same elements was 37% of the maximum value of the analytical solution. The magnitude of the tensile stress from the FEM using 6 elements was 61% of the maximum value of the analytical solution and the magnitude of the compressive stress from the FEM using the elements was 83% of the maximum value of the analytical solution. Vertical stresses, which were obtained from the analytical solution, showed a continuous distribution with the depth of the soil beam, whereas the vertical stresses from the FEM showed a discrete distribution corresponding to each element. The results also showed that the average value of the vertical stresses of each element was close to that of the pore water pressure. A comparison of the vertical displacements computed at the near vertical center line of the soil beam from the FEM with those of the analytical solution showed that the magnitude of the vertical displacement from FEM using 3 elements was 35% of the value of the analytical solution and the magnitude of the vertical displacement from FEM using 6 elements was 57% of the value of the analytical solution.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.17 no.6
• /
• pp.725-730
• /
• 2007

Gray-level histogram-based threshold selection methods such as Otsu's method, Huang and Wang's method, and etc. have been widely used for the threshold selection in image processing. They are simple and effective, but take too much time to determine the optimal multilevel threshold values as the number of thresholds are increased. In this paper, we measure correlation between gray-levels by using the Gaussian function and define a Gaussian-type finite mixture distribution which is combination of the Gaussian distribution function with the gray-level histogram, and propose a fast and effective threshold selection method using it. We show the effectiveness of the proposed through experimental results applied it to three images and the efficiency though comparison of the computational complexity of the proposed with that of Otsu's method.

• Korean Journal of Remote Sensing
• /
• v.29 no.4
• /
• pp.407-413
• /
• 2013

The Modified Aerosol Factor (MAF) derived from spectral Single-Scattering Albedo (SSA) values was created to express the light absorption properties according to aerosol types. As a factor of the MAF, slope of a linear regression line for SSA at four wavelengths shows positive value for dust aerosol, while negative values were found for mixing with other types of aerosol. The negative values were shown by anthropogenic and smoke aerosols. The modified SSA at 1020 nm was also calculated. MAF was calculated by summing the slope and modified SSA. MAF was -1.0 for the anthropogenic and smoke aerosol and 1.5 for the dust particles. Those values were decreased by increasing light absorption property.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.4
• /
• pp.39-46
• /
• 2013

Cooperative spectrum sensing can improve sensing reliability, compared with single node spectrum sensing. In addition, Eigenvalue-based spectrum sensing has also drawn a great attention due to its performance improvement over the energy detection method in which the more smoothing factor, the better performance is achieved. However, the more smoothing factor in Eignevalue-based spectrum sensing requires the more sensing time. Furthermore, more reporting time in cooperative sensing will be required as the number of nodes increases. Subsequently, we in this paper propose an Eigenvalue and superposition-based spectrum sensing where the reporting time is utilized so as to increase the number of smoothing factors for autocorrelation calculation. Simulation result demonstrates that the proposed scheme has better detection probability in both local as well as global detection while requiring less sensing time as compared with conventional Eigenvalue-based detection scheme.

• The Korean Journal of Food And Nutrition
• /
• v.23 no.2
• /
• pp.218-225
• /
• 2010

To make sponge cake using Lentinus edodes powder, which is useful and valuable as a functional food material, we tested samples with 3, 6, 9, and 12% L. edodes powder to ascert200ain the quality characteristic and make optimize preparation. Samples and L. edodes powder-free control sponge cakes were compared in terms of quality characteristics including batter viscosity and specific gravity, moisture content, volume index, weight, color, textural characteristics, and sensory qualities, to determine the optimal ratio of L. edodes powder in the formulation. Viscosity and specific gravity of sample and control batter were not significantly different. Moisture content of the sample and control sponge cake also did not differ significantly, and weight of sample and control sponge cakes did not differ appreciably. The volume index of the samples displayed contrasting values, increasing with 3~6% L. edodes powder and decreasing with 9~12% powder. L, a, and b crust color values of samples sponge cakes were lower than those of control cakes. The L and a values of the control cakes was maximal, with values progressively decreasing with incorporation of more L. edodes powder. The b value decreased by 3% with the addition of up 6% L. edodes powder with no further decrease thereafter. L. edodes powder was the lower value. So was the color a, and L. edodes powder increased, a-values decreased. 3% difference was shown in b, the color and none between the samples with 6~12%. L. edodes powder showed lower values making a comparison with the control. Hardness and fracturablility were not appreciably affected by 3% L. edodes powder, but was affected by concentrations 6%. Fracturability og sample sponge cakes was consistently lower than control cakes. Fracturability made little difference in 3% samples, but it was not the same with more than 6% L. edodes powder samples; the samples showed lower value than the control. Adhesiveness was not significantly affected. Chewiness was lower in all sample cakes except those prepared with 3% L. edodes powder. Use of L. edodes powder conferreds higher resilience values as compared to thecontrols. Sensory attributes of color, flavor, softness and overall acceptability were the highest in control sponge cakes, as the amount of L. edodes powder increased, the acceptability decreased. L. edodes-flavor, pleasant taste and off-flavor were the lowest in control cakes, and values increased as the amount of L. edodes powder increased. The control sponge cakes showed the highest values in egg-flavor and moistness, which progressively increased as added L. edodes powder increased. The results indicate that control sponge cakes displayed were. the highest overall acceptability, with acceptability decreasing and it decreased as L. edodes powder content increased. However, 3~6% L. edodes powder can produce an acceptable product, and may be used as anoptimized mixture ratio.

• Journal of Elementary Mathematics Education in Korea
• /
• v.19 no.3
• /
• pp.371-386
• /
• 2015

There has been little consensus on how to define and use the Korean mathematical terms, bi-ui-gap and bi-yul. This study compares four perspectives of bi-ui-gap and bi-yul proposed and discussed in Korean mathematics education community and examines the ways of using the terms adopted since the 6th national curriculum. Based on the analysis that previously proposed perspectives conflict each other, this study proposes as a way to synthesize different perspectives of bi-ui-gap and bi-yul by analyzing the terms in the internal and external ratio contexts. This study proposes that bi-ui-gap be used to represent 'a value of $A{\div}B$' rather than 'a value originated from a ratio A:B' or 'a fraction form ${\frac{B}{A}}$.' This study also proposes that bi-yul or bae-yul be used in the internal ratio context and a new term, such as dan-wi-yul, be created for the external ratio context.