• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.6
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• pp.485-491
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• 2013

Recently, with the proliferation of social network services, users and many companies hope that their information spread more faster. In order to study the information diffusion in the social networks, many algorithms such as greedy algorithm and heuristic algorithm have been proposed. However, the greedy algorithm is too complicated to use in real-life social network, and the heuristic algorithms have been studied under the uniform distribution of diffusion probability, which is different from the real social network property. In this paper, we propose an heuristic information diffusion maximization algorithm based on diffusion probability and node degree. For performance evaluation, we use real social network database, and it is verified that our proposed algorithm activates more active nodes than existing algorithms, which enables faster and wider information diffusion.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.2
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• pp.132-140
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• 1993

The design of LNG ship needs very high level structural design/analysis technology compared with conventional ship types because it requires perfect security against the extremly dangerous and cryogenic cargo. Hence, present paper describes the general procedure of the structural safety assessment for independent tank type LNG ship, which contains following items. 1) Long term prediction of the wave induced stresses including ship motion analysis, structural analysis of hull and tank and stochastic analysis process of ocean waves. 2) Fatigue strength analysis of a tank structure based on the S-N approach. 3) Structural safety assessment against the fatigue crack propagation based on the LBF(Leak Before Failure) concept. The first report focuced on the item (1) (2) and example calculation was performed on a prototype LNG ship. The remained part will be covered by the second report.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.119-126
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• 2008

In this paper, the loop coupling model for the analysis of end launcher rectangular waveguide adapter are proposed. The formula of input impedance from this model are presented. The influence of propagation mode and higher modes in rectangular waveguide are analyzed and design parameters of the end launcher adapter are investigated. The computational results between the proposed theoretical analysis and the previous papers are compared and are verified by HFSS. The end launcher rectangular waveguide adapter consists of the coupling geometry which is connected the inner conductor of $50{\Omega}$ coaxial line through into the 17.6mm feeding loop in a WR90 commercial waveguide, and the VSWR is maximum 2.0 over operating frequency from 7.5GHz to 10.6GHz.

• Food preservation and processing industry
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• v.7 no.2
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• pp.2-2
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• 2008

발효는 인류의 역사와 함께 해 왔으며 과학 기술발전에 따라 자연 발효에서 관리하는 방법으로 급격히 변하고 있다. 발효는 미생물과 미생물이 생산한 효소의 작용으로 일어나는바 미생물 관리를 통하여 실로 다양한 제품 생산이 가능하고 역할의 범위도 지극히 넓다. 즉 원하는 최종 제품의 종류에 따라 미생물을 선택하거나 발효조건을 관리하여 목적 지향적 완제품 생산이 가능한 경우가 많다. 한국인의 식단을 이루는 기본은 각종 발효 제품을 근간으로 하는 조미료이며, 조미료에 따라 맛의 변화가 온다. 발효를 통하여 소화성의 증대, 비타민 등 새로운 미량물질의 생산, 풍미의 개선 혹은 새롭게 창조하거나 저장기간을 연장하기도 하며, 사용하는 원료와는 완전히 다른 신제품을 만들어 내기도 한다. 근래의 연구 결과들을 살펴보면 여러 기능성 물질이 발효를 통하여 생성되며 이들이 인체 내에서 긍정적 역활을 한다는 것이 밝혀지고 있다. 전통식품 중 발효식품은 가장 큰 비중을 차지하며 곡류 중심의 식단에 맛을 부여하여 먹는 즐거움을 주고 전망있는 다른 산업으로 발전 해 나갈 수 있는 특성이 있다. 발효식품은 다양한 원료를 사용 할 수 있고 원료에 따라 많은 서로 다른 제품생산이 가능하다. 우리나라에서 생산되는 주요 발효식품은 김치를 포함한 절임류, 곡물 또는 과실을 이용한 주류, 어류로 각종 젓갈을 만들 수 있으며 근래 수요가 늘고 있는 요구르트 등도 인기 있는 발효식품이다. 특히 발효식품에 관여하는 미생물들이 probiotic으로 작용하여 장내 미생물의 항산성 유지 및 유해 세균의 증식억제 등 긍정적 역할을 하며 우유 발효균으로 알려진 젖산균류 뿐만 아니라 다른 세균들도 probiotic으로 작용한다는 것이 밝혀지고 있으며, 특히 장류에 많이 관여하는 Bacillus 속 들의 긍정적 역할이 속속 알려지고 있다. 또한 발효를 통하여prebiotic도 만들어지는 것을 알 수 있다. 앞으로 발효식품의 기능성의 과학적 입증 발효의 과학적 관리, 제품의 다양화와 함께 안전성도 검토할 대상이다. 또한 심도있게 발효 관여 미생물을 탐색, 동동하고 발효기반의 이용확대, 맞춤형 특수 미생물의 탐색과 용도 확인 등 노력이 필요하다. 우리나라 전통식품 중 큰 비중을 차지하는 발효식품을 세계화하기 위해서는 건강기능성의 과학적 기반 구축과 전문 학술 활동을 통한 홍보, 현지 식품에 맞는 fusion food의 개발도 필요하다. 발효식품을 포함한 전통식품은 경제적 측면과 함께 문화적 가치가 동시에 고려되어야 하고 다문화 추세에 따라 유연성 있게 변화를 수용 할 필요도 있다. 전통 발효식품을 우리 식문화를 세계에 전파시키는 좋은 매체로 활용 할 수 있을 것이다.

• The Transactions of the Korea Information Processing Society
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• v.2 no.5
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• pp.677-690
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• 1995

In this paper, we propose the high efficiency data compression capable of error control using block-sorting, move to front(MTF) and arithmetic code with variable length in to fixed out. First, the substring with is parsed into length N is shifted one by one symbol. The cyclic shifted rows are sorted in lexicographical order. Second, the MTF technique is applied to get the reference of locality in the sorted substring. Then the preprocessed sequence is coded using VF(variable to fixed) arithmetic code which can be limited the error propagation in one codeword. The key point is how to split the fixed length codeword in proportion to symbol probabilities in VF arithmetic code. We develop the new VF arithmetic coding that split completely the codeword set for arbitrary source alphabet. In addition to, an extended representation for symbol probability is designed by using recursive Gray conversion. The performance of proposed method is compared with other well-known source coding methods with respect to entropy, compression ratio and coding times.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4B
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• pp.300-308
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• 2012

Many indoor location tracking technologies have been proposed. Generally indoor location tracking using TOA signal is used, there is a weak point that it's difficult to track the location due to obstacles like a refraction, reflection and dispersion of radio wave. In this paper, we apply ETOA(Estimated-TOA) algorithm in NLOS(Non-Line-Of-Sight) environment to solve above problem. In NLOS environment, TOA value between Beacon and Mobile node is predicted by ETOA algorithm and the tracking of indoor location is also possible to identify using two NLOS beacons of three beacons by this algorithm. We show that the proposed algorithm is accurate location tracking is accomplished using the applying the proposed algorithm to indoor moving robot and the inertia sensor of robot and Kalman filter algorithm.

• The Journal of the Acoustical Society of Korea
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• v.39 no.4
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• pp.364-370
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• 2020

Rocket noise generated from the exhaust plume produces the enormous acoustic loading, which adversely affects the integrity of the electronic components and payload (satellite) at liftoff. The prediction of rocket noise consists of two steps: the supersonic jet exhaust is simulated by a method of the Computational Fluid Dynamics (CFD), and an acoustic transport method, such as the Helmholtz-Kirchhoff integral, is applied to predict the noise field. One of the difficulties in the CFD step is to remove the boundary reflection artifacts from the finite computation boundary. In general, artificial damping, known as a sponge layer, is added nearby the boundary to attenuate these reflected waves but this layer demands a large computational area and an optimization procedure of related parameters. In this paper, a cost-efficient way to separate the reflected waves based on the two microphone method is firstly introduced and applied to the computation result of a laboratory-scale supersonic jet noise without sponge layers.

• Journal of the Korean Geotechnical Society
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• v.34 no.8
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• pp.51-64
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• 2018

Korean peninsula is known to be far from the plate boundary and not to generate large-scale earthquakes. However, earthquakes recently occurred in Gyeongju (2016/09/12, $M_L=5.8$) and Pohang (2017/11/15, $M_L=5.4$). The interest in earthquake engineering has increased, and various studies are actively underway by recently events. However, the seismic station network in Korea is less dense than that of the western U.S., resulting in the lack of data for detailed analyses of earthquakes. Therefore, KMA (Korea Meteorological Administration) set up temporary seismic stations and recorded ground motions from aftershocks. In this study, characteristics of Pohang seismic propagation and generation of bedrock motion are analyzed through the aftershock ground motion records at both permanent and temporary stations, as well as through the collected geological structure and site information. As a result, the response at Mangcheon-Li shows evidences of basin effects from both geology structures and measured aftershock motions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.3
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• pp.280-292
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• 1989

In this paper, the error rate equations of digitally modulated signals transmitted through the channel which is not only Gaussian/Impulsive noise but also multi-path fading have been derived. Using the derived equations for the error probabilities of ASK, QAM, CPSK, DPSK, FSK, and MSK signals, the error rate performances of digital modulation systems have been evaluated and represented in the graphs as the functions of CNR, Impulsive indes, the ratio of Gaussian noise power component to Impulsive noise power component, and fading figures. The results show that, in the deep fading environment, the error is occurred more frequency by Gaussian noise than Impulsive noise. And the comparison of various systems certifies that PSK is superior to the ohter systems in the deep fading or shallow fading environment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.3
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• pp.245-252
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• 2010

This paper proposes an improved filter synthesis method for dual-band filters based on coupled lines loaded with shunt stubs. The conventional design method relies on equality of the response of the conventional single-band filter and its dual-band counterpart at two frequencies. On the other hand, the proposed method is based on equivalence of the propagation constants and the image impedances of the two filters. Therefore, the proposed method does not suffer from bandwidth reduction phenomena, which requires complex compensating process in the conventional method. Also, the alternative design parameters provided by the demonstrated method enable to construct dual-band filters with more flexibility. For experimental verification, a Chebyshev type dual-band filter with center frequencies at 1 GHz and 3.5 GHz is designed and fabricated. The measured results are in excellent agreement with the full-wave simulated results.