• The KIPS Transactions:PartC
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• v.16C no.1
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• pp.13-20
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• 2009

Recently, as traffic flooding attacks such as DoS/DDoS and Internet Worm have posed devastating threats to network services, rapid detection and proper response mechanisms are the major concern for secure and reliable network services. However, most of the current Intrusion Detection Systems (IDSs) focus on detail analysis of packet data, which results in late detection and a high system burden to cope with high-speed network traffic. In this paper we propose an SNMP-based lightweight and fast detection algorithm for traffic flooding attacks, which minimizes the processing and network overhead of the detection system, minimizes the detection time, and provides high detection rate. The attack detection algorithm consists of three consecutive stages. The first stage determines the detection timing using the update interval of SNMP MIB. The second stage analyzes attack symptoms based on correlations of MIB data. The third stage determines whether an attack occurs or not and figure out the attack type in case of attack.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.3
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• pp.264-274
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• 2014

Time synchronization becomes a critical issue in underwater acoustic networks (UANets) because nodes cooperate together or individually work by communicating each other in diverse underwater applications. Compared with the time synchronization approaches in terrestrial networks, several intrinsic limitations of UANets (e.g., the unavailability of GPS, long propagation delay, mobility due to currents, limited energy consumption, or low data rate) need to be considered in synchronizing the timing among underwater nodes. For the purpose of developing more efficient time synchronization protocols for UANets, we review the existing approaches, which estimate both the clock offset and the clock skew of underwater nodes. Finally, we outline the state-of-the art time synchronization protocols for UANets by comparing and summarizing them according to their synchronization characteristics.

• Journal of the Korean Magnetics Society
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• v.21 no.2
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• pp.61-66
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• 2011

The miniaturization of electrostatic precipitator is becoming a key element to the success of the efficient electrostatic precipitator due to the limited space allowed to install electrostatic precipitator in subway tunnel. Nowadays, a research on electrostatic precipitator in urban railroad equipment technology is under an active study. Finite element method has been used one of the most popular techniques, but it consumes a lot of time especially in computation iterations. Accordingly, the lumped parameter analysis can be an alternative tool to FEM because of its computation iteration capability with fair accuracy. In this paper, lumped parameter model and the simulation results are presented. In addition, the result of lumped parameter analysis is compared with those obtained from finite element analysis for verification.

• The Journal of Bigdata
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• v.5 no.1
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• pp.197-208
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• 2020

Lexical ambiguity means that a word can be interpreted as two or more meanings, such as homonym and polysemy, and there are many cases of word sense ambiguation in words expressing emotions. In terms of projecting human psychology, these words convey specific and rich contexts, resulting in lexical ambiguity. In this study, we propose an emotional classification model that disambiguate word sense using bidirectional LSTM. It is based on the assumption that if the information of the surrounding context is fully reflected, the problem of lexical ambiguity can be solved and the emotions that the sentence wants to express can be expressed as one. Bidirectional LSTM is an algorithm that is frequently used in the field of natural language processing research requiring contextual information and is also intended to be used in this study to learn context. GloVe embedding is used as the embedding layer of this research model, and the performance of this model was verified compared to the model applied with LSTM and RNN algorithms. Such a framework could contribute to various fields, including marketing, which could connect the emotions of SNS users to their desire for consumption.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.2
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• pp.68-76
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• 2010

Touch-enabled technology is increasingly being accepted as a main communication interface between human and computers. However, conventional touchscreen technologies, such as resistive overlay, capacitive overlay, and SAW(Surface Acoustic Wave), are not cost-effective for large screens. As an alternative to the conventional methods, we introduce a newly emerging method, an optical imaging touchscreen which is much simpler and more cost-effective. Despite its attractive benefits, optical imaging touchscreen has to overcome some problems, such as heavy computational complexity, intermittent ghost points, and over-sensitivity, to be commercially used. Therefore, we designed a hardware controller for signal processing and multi-coordinate computation, and proposed Infrared-blocked DA(Dark Area) manipulation as a solution. While the entire optical touch control took 34ms with a 32-bit microprocessor, the designed hardware controller can manage 2 valid coordinates at 200fps and also reduce energy consumption of infrared diodes from 1.8Wh to 0.0072Wh.

• 전자공학회논문지 IE
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• v.47 no.1
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• pp.41-47
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• 2010

It is very important to prolong the lifetime of wireless sensor networks by using their limited energy efficiently, since it is not possible to change or recharge the battery of sensor nodes after deployment. LEACH protocol is a typical routing protocol based on the clustering scheme for the efficient use of limited energy. It is composed of a few clusters, which consist of head nodes and member nodes. Though LEACH starts from the supposition that all nodes have data transferred to a head, there must be some nodes having useless data in actual state. In this paper we propose a power saving scheme by making a member node dormant if previous sensed data and current data is same. We evaluate the performance of the proposed scheme in comparison with original clustering algorithms. Simulation results validate our scheme has better performance in terms of the number of alive nodes as time evolves.

• Journal of the Korea Society of Computer and Information
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• v.20 no.2
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• pp.157-167
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• 2015

There is literature addressing to cultural aspects of alcohol and alcoholism. However, scholars have paid little attention to study what will happen to alcohol consumption behavior and alcoholism if there is a national government cultural intervention, so that the alcohol drinking culture would change in association with the change of internal institution in a society. This work attempted to study this research question. For this purpose, I selected Mongolia as a research case and examined survey data, statistical data, and data from research-based resources, referring to the last 70 years profile of Mongolian alcohol per capital consumption and alcoholism as well as studying Mongolian historical sources for measuring Mongolian traditional alcohol drinking customs. The data I gathered and observed during this research proved that there is a huge difference between the current drinking culture among younger generation and Mongolian traditional cultural context that was respected and strictly followed by their ancestors. Findings suggest that there has been a parallel increase between the change of alcohol drinking culture and alcohol consumption in connection with the modernization.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.5
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• pp.561-566
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• 2014

The high power COB(Chip on Board) LED, densely arranged chips on a board, are increasing to resolve heat problems in LED that has luminous semiconductor chips as main materials. In case of high-power COB LED, protection against heat is necessary due to the power consumption is high. Also if the temperature of device increases, the optical emission becomes less efficient and the life rapidly reduces due to thermal stress. This study packaged 13.5W COB LED and heat sink with difference form and produced 13.5W COB LED down-light heat sink by analyzing the thermal modes with Solidworks Flow Simulation. And finally it analyzed and evaluated the thermal modes using contacting and non-contacting thermometers.

• Journal of the Korean Home Economics Association
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• v.38 no.12
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• pp.241-248
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• 2000

포도는 전세계에서 널리 소비되는 과실로 포도 과피에 존재하는 천연색소인 flavonoid는 혈중 콜레스테롤 함량 저하, 항알러지성, 항암성, 항바이러스성, 항염성의 생리적 기능이 있다고 알려져 있다. 최근에 들어와 이들 과실주스 가공에 열처리를 최소화하는 살균방법으로 자연 그대로의 영양성분, 맛과 향기 개선을 위한 초고압 처리에 관한 연구가 폭넓게 이루어지고 있다. 본 연구는 주스에서 문제가 되고 있는 ethanolic spoilage 균주인 S. cerevisiae의 초고압 살균 효과와 세포 구조적 형태를 연구하였다. 1.2$\times$$10^{6}$ cfu/ml의 S. cerevisiae를 포도주스에 접종하고 24시간 배양하여 멸균한 high barrier주머니에 20m1씩 넣고 2$0^{\circ}C$ 에서 200-600 MPa 조건으로 0-20분 동안 초고압 장치로 실시하였다. 생균수는 YM agar로 poured 방법으로 실시하였으며 200 MPa에서 5, 10, 15, 20분 후의 생균수는 각각 2.2$\times$$10^{7}$ , 4.5$\times$$10^4$, 2.8$\times$$10^4$, 9.8$\times$$10^3$, 9.5$\times$$10^3$cfu/ml로 tailing 현상을 관찰하였고, 400 MPa에서 5분 후 급격하게 감소하였다. S. cerevisiae의 사멸속도는 초고압 처리가 높을수록 증가했으며 세포 손상도는 압력과 처리시간이 길수록 증가하였다. 이들 조건에 따른 효모 세포의 구조적 관찰을 scanning electron microscopy와 electron microscopy로 하였다. S. cerevisiae 세포는 압력에 의한 pinhole, surface roughening을 발견하였고, 세포 내부의 세포질, 액포, 핵 손상과 세포질 물질들이 압력에 의하여 세포벽으로 이동하여 내부가 비어있는 현상을 관찰하였다.

• Journal of Korea Game Society
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• v.11 no.5
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• pp.53-65
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• 2011

If we analyze games and game communities which are mostly consumed by the young, we can get the meaningful analysis result of youth culture. The content analysis and the discourse analysis methods were used in this study since the relationship between media and culture was exquisitely reciprocal. The object of analysis is the domestic community of the simulation game, Sims 2, which reflects the identities of the game players. I was searching for the social and cultural meaning of the game activities, and could find the content's characteristics of 'Sims 2' players' discourses. The results showed that the game media has social and cultural significance by providing the players a self-realization, identity workshop, virtual identity that diverges from their own ones with an alternative sex, constructing a cultural property with the involved game players, and increasing their virtual consumption and self-examination of antisocial behaviors in the game.