• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1776-1778
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• 1998

KEPCO has been constructing the 765 kV double circuit transmission line since 1997. It is worried that the 765 kV transmission lines make TV interference(Ghost and Blocking) due to high tower and multi sub-conductors. This paper presents the mechanism, the measuring method and the results of TV ghost and blocking measurement using a new TV ghost measurement system in a vehicle which was developed by KEPRI.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.6
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• pp.135-148
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• 2004

Recently, it is difficult to block the spam mail that changes variously with past spam distinction method by words. To solve such problem, This paper propose the method of generating spam distinction rule using URL frequency analysis. It is consist of collecting spam, drawing URL that get into characteristic from collected spam mail. URL noonalizing, generating spam distinction rule by time frequency, and blocking mail. It can effectively block various types of spam mail and various forms of spam mail that change.

• The Transactions of the Korea Information Processing Society
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• v.6 no.3
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• pp.692-698
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• 1999

In this paper, we proposed the channel assignment scheme for the CDMA(Code Division Multiple Access) cellular system using power allocation concept. Also, the performance of the proposed scheme was analyzed and it was compared with the channel assignment scheme using the fixed power allocation method in the CDMA cellular system. The proposed scheme allocates the power adaptively in according to the traffic loads and the traffic distribution pattern of neighbor cells in the forward link. We found that total call blocking probability (Pr) is more dependent on blocking probability($P_B$) than outage probability (Po) under physical number of channels ($C_{th}$)=30. Pr(Call Blocking Probability) is dependent on $P_B$(Blocking Probability) and Po(Outage Probability) at the same ratio under $C_{th}$=32, in which case P$P_{TA}$(blocking probability for the adaptive power allocation) is greater than $P_{TF}$(blocking probability for the fixed power allocation) about 6%.

• Journal of the Korea Society for Simulation
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• v.17 no.4
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• pp.241-247
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• 2008

In this study we consider an M/D/1 queue with a finite buffer. Due to the finiteness of the buffer capacity arriving customers can not join the system and turn away without service when the buffer is full. Even though a computational method for blocking probabilities in an M/D/1/K queue is already known, it is very complex to use. The aim of this study is to propose a new way to compute blocking probability by using (max,+)-algebra. Our approach provide a totally different and easier way to compute blocking probabilities and it is, moreover, immediately applicable to more generous queueing systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2369-2381
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• 1999

In this paper, we propose an iterative algorithm for reducing the blocking artifact in block transform-coded images by using a wavelet transform. In the proposed method, an image is considered as a set of one-dimensional horizontal and vertical signals and one-dimensional wavelet transform is utilized in which the mother wavelet is the first order derivative of a Gaussian like function. The blocking artifact is reduced by removing the blocking component, that causes the variance at the block boundary position in the first scale wavelet domain to be abnormally higher than those at the other positions, using a minimum mean square error (MMSE) filter in the wavelet domain. This filter minimizes the MSE between the ideal blocking component-free signal and the restored signal in the neighborhood of block boundaries in the wavelet domain. It also uses local variance in the wavelet domain for pixel adaptive processing. The filtering and the projection onto a convex set of quantization constraint are iteratively performed in alternating fashion. Experimental results show that the proposed method yields not only a PSNR improvement of about 0.56-1.07 dB, but also subjective quality nearly free of the blocking artifact and edge blur.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.11B
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• pp.730-735
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• 2005

While the E-mail is a important way of fast communication in these days. it is real that the E-mail is often misused as a commercial advertisement method and creates many social problems. Even though various filtering techniques for blocking spam mails have been developed, reliability of mail systems is decreased by misreading normal mails as spam mails, i.e. false-positive errors. In this paper, the SMBC(Spam Mail Blocking Center) platform employing spam mail recovery method based on privacy information is proposed and designed. The SMBC is designed in frame layer based on spam blocking system of proxy sewer and can be physically implemented in various topology so that flexible development with layered module is possible. Using privacy information makes the proposed SMBC platform minimize processing load and false-positive error rates so that it can improve mail system reliabilities.

• Geomechanics and Engineering
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• v.29 no.4
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• pp.391-405
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• 2022

A newly proposed grouting simulation method, the sequential diffusion solidification method was introduced into the numerical simulation of combined bi-borehole grouting. The traditional, critical and difficult numerical problem for the temporal and spatial variation simulation of the slurry is solved. Thus, numerical simulation of grouting and blocking of flowing water in karst conduits is realized and the mechanism understanding of the combined bi-borehole technology is promoted. The sensitivity analysis of the influence factors of combined bi-borehole grouting was investigated. Through orthogonal experiment, the influences of proximal and distal slurry properties, the initial flow velocity of the conduit and the proximal and distal slurry injection rate on the blocking efficiency are compared. The velocity variation, pressure variation and slurry deposition phenomenon were monitored, and the flow field characteristics and slurry outflow behavior were analyzed. The interaction mechanism between the proximal and distal slurries in the combined bi-borehole grouting is revealed. The results show that, under the orthogonal experiment conditions, the slurry injection rate has the greatest impact on blocking. With a constant slurry injection rate, the blocking efficiency can be increased by more than 30% when using slurry with weak time-dependent viscosity behavior in the distal borehole and slurry with strong time-dependent viscosity behavior in the proximal borehole respectively. According to the results of numerical simulation, the grouting scheme of "intercept the flow from the proximal borehole by quick-setting slurry, and grout cement slurry from the distal borehole" is put forward and successfully applied to the water inflow treatment project of China Resources Cement (Pingnan) Limestone Mine.

• Journal of Digital Contents Society
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• v.15 no.4
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• pp.481-489
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• 2014

In this paper, the automatic standby power blocking socket outlet to reduce standby power by blocking power threshold is implemented. Where, the standby power means a flowing power when a disused power electronic is plugged into the socket outlet. The proposed socket outlet can cut off the standby power by establishing a proper block power threshold electronic device according to each electronic device because it can monitor the amount of power through the smart machines such as the real-time PC or mobile phone and directly control the blocking power threshold. The software is implemented by using Visual Studio software, code vision and SN8 C studio, and the hardware is embodied in ATmega128, SN8F27E93S, USB to UART, and relay etc. Through the simulation, we find that the standby power of the proposed method is similar to that of the conventional method in case of the cellular phone but the standby power of the proposed method is much less than that of the conventional method in case of the computer, air conditioning, and set-top box. Therefore, it is proved that the proposed socket outlet has a superior performance in terms of the standby power.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.96.1-96.1
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• 2010

현재 태양광 시장에 진출한 대부분의 Si계열 태양전지는 복잡한 공정과 원재료 고갈, 높은 가격으로 인해 한계에 직면에 있는 상태이다. 최근 많은 연구소나 학교에서는 기존의 Si계열 태양전지를 대체할 대안으로 염료 감응형 태양전지에 대해서 높은 관심을 보이고 있으며, 그동안의 연구개발로 단위 셀 면적에서는 상용화에 근접한 효율을 확보한 상태이다. 염료 감응형 태양전지의 작동과정을 간단히 단계별로 살펴보면 나노 결정 산화물 반도체 표면에 흡착된 염료분자가 가시광선을 흡수하면 전자는 HOMO에서 LUMO로 천이하고 이 들뜬 상태의 전자는 다시 에너지 준위가 낮은 반도체 산화물의 전도띠로 주입된다. 주입된 전자는 나노 입자간 계면을 통하여 투명 전도성막으로 확산, 전달되고 산화된 염료분자는 전해질 I-에 의해 다시 환원되어 중성 분자가 된다. 그러나 표면상태 전자 중 일부는 산화된 염료와 다시 결합하거나, 전해질의 $I^{3-}$ 이온을 환원시키기도 한다. 이와 같은 과정은 암전류를 증가시키면서 반도체 전극 막의 성능을 저해하는 주원인이 된다. 전자의 재결합은 투명 전극을 통해서도 가능하기 때문에 투명 전극에 얇은 blocking layer를 도포한 후 나노 결정 산화물 반도체 전극을 제작하면 전지 특성을 향상시킬 수 있다. 본 실험에서 우리는 졸-젤 법으로 $TiO_2$ blocking layer 졸을 만들었고 간단하며 저가공정이 가능한 스크린 프린팅 방법으로 blocking layer를 형성하는 실험을 진행하였다. 전도띠 에너지가 높은 반도체 물질로 표면을 처리하면 $TiO_2$-전해질 간 계면에 에너지 장벽이 형성되어 재결합을 줄여 모든 광전특성이 향상 되었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.10B
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• pp.1921-1936
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• 1999

In this paper, we analyze the blocking artifact in block transform-coded images and propose a classification algorithm which classifies each horizontal and vertical block boundary into four regions of EQ, BA, EE, and AE according to the characteristics of the blocking artifact. We also compare the performance of several blocking artifact reduction methods which can reduce blocking artifact in block transform-coded images well. As the blocking artifact reduction methods, the LOT, Kim's wavelet transform-based method, Yang's POCS, Paek's POCS, and Jang's CM have been selected. Experimental results show that each horizontal and vertical block boundary classified by using the proposed classification algorithm yields different characteristics of discontinuities due to the blocking artifact according to the classified region. It is also shown that the blocking artifact reduction methods using wavelet transform yield better performance over the other methods.