• Journal of the Institute of Convergence Signal Processing
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• v.18 no.2
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• pp.43-48
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• 2017

The underwater transients signals contain the characteristics of complexity, time varying, nonlinear, and short duration. So it is very hard to model for these signals with reference patterns. In this paper we separate the whole length of signals into some short duration of constant length with overlapping frame by frame. The 20th LPC(Linear Predictive Coding) coefficients are extracted from the original signals using Durbin algorithm and applied to neural network. The 65% of whole signals were learned and 35% of the signals were tested in the neural network with two hidden layers. The types of the whales for sound classification are Blue whale, Dulsae whale, Gray whale, Humpback whale, Minke whale, and Northern Right whale. Finally, we could obtain more than 83% of classification rate from the test signals.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.8
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• pp.1486-1491
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• 2017

In this paper, we propose a private multimedia caching scheme based on wireless local area network (WLAN) to improve the quality of service for high capacity and high quality multimedia streaming services which are recently increasing and to reduce the traffic load of core networks. The proposed caching scheme stores multimedia in the storage device mounted on WLAN APs and provides streaming services on its own without Internet connection in accordance with the request from clients. We have implemented a test network based on real commercial networks and measured the performance of the proposed caching scheme in terms of frames per second (FPS) and buffering time. According to the performance measurement results, the proposed caching scheme can reduce the average buffering time by 73.3% compared to the conventional streaming scheme. In addition, the proposed caching scheme can also improve the average FPS by 71.3% compared to the conventional streaming scheme.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.120-120
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• 2023

본 연구에서는 CCTV 영상 내 빗줄기의 특성을 바탕으로 강우강도를 산정하기 위한 합성곱 신경망(CNNs, Convolutional Neural Networks) 기반 강우강도 산정 모형을 제안하였다. 중앙대학교 및 한국건설생활환경시험연구원 내 대형기후환경시험실에서 얻은 CCTV 영상들을 대상으로 연구를 수행하고, 우적계 등과 같은 지상 관측자료와 강우강도 산정 결과를 비교·검증하였다. 먼저, CCTV 영상 내 빗줄기의 미세한 변동 특성을 반영하기 위해 데이터 전처리 작업을 진행하였다. 이는 원본 영상으로부터 빗줄기 층을 분리해내는 과정, 빗줄기 층에서 빗물 입자를 분리해내는 과정, 그리고 빗물 입자를 인식하는 과정 등 총 세 단계로 구분된다. 합성곱 신경망 기반 강우강도 산정 모형 구축을 위해 영상 전처리가 완료된 데이터들을 입력값으로 설정하고, 촬영 시점에 대응되는 지상관측 자료를 출력값으로 고려하여 강우강도 산정모형을 훈련시켰다. CCTV 원자료 내 특정 영역에 편향되어 강우강도를 산정하는 과적합 현상의 발생을 방지하기 위해 원자료 내 5개의 관심 영역(ROI, Region of Interest)을 설정하였다. 추가로, CCTV의 해상도를 총 4개(2560×1440, 1920×1080, 1280×720, 720×480)로 구분함으로써 해상도 변화에 따른 학습 결과의 차이를 분석·평가하였다. 이는 기존 사례들과 비교했을 때, CCTV 영상을 기반으로 빗줄기의 거동 특성과 같은 물리적인 현상을 직간접적으로 고려하여 강우강도를 산정했다는 점과 더불어 머신러닝을 적용하여 강우 이미지가 갖는 본질적인 특징들을 파악했다는 측면에서, 추후 본 연구에서 제안한 모형의 활용 가치가 극대화될 수 있을 것으로 판단된다.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.5
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• pp.817-826
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• 2023

In this paper, a fault determination methodology based on an artificial neural network was proposed to protect the system from faults on the lines in the smart grid distribution system. In the proposed methodology, first, it was designed to determine whether there is a low impedance line fault (LIF) based on the magnitude of the current RMS value, and if it is determined to be a normal current, it was designed to determine whether a high impedance ground fault (HIF) is present using Normal/HIF classifier based on artificial neural network. Among repetitive DSP module-based algorithm verification tests, the normal/HIF classifier recognized the current waveform as normal and did not show reclosing operation for the cases of normal state current waveform simulation test where the RMS value was smaller than the minimum operating current value. On the other hand, for the cases of LIF where RMS value is greater than the minimum operating current value, the validity of the proposed methodology could be confirmed by immediately recognizing it as a fault state and showing reclosing operation according to the prescribed procedure.

• Journal of Korea Multimedia Society
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• v.3 no.3
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• pp.253-262
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• 2000

This paper proposes a new RBF neural network that determines the number and the center of hidden neurons based on the adaptive feature extraction for the input data. The principal component analysis is applied for extracting adaptively the features by reducing the dimension of the given input data. It can simultaneously achieve a superior property of both the principal component analysis by mapping input data into set of statistically independent features and the RBF neural networks. The proposed neural networks has been applied to classify the 200 breast cancer databases by 2-class. The simulation results shows that the proposed neural networks has better performances of the learning time and the classification for test data, in comparison with those using the k-means clustering algorithm. And it is affected less than the k-means clustering algorithm by the initial weight setting and the scope of the smoothing factor.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.127-134
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• 2012

Four river project in the South Korea contributes to solve flood damages and water shortages. Also, it has purpose for creating water ecosystem and improving the level of people' cultural leisure and quality of life through inducing water quality improvement and river restoration. It is necessary to monitor a variety of observing data in river areas among dozens to hundreds of kilometer for safe river administration. The 20th construction area of the four river project is located on Hapcheon areas, where wireless mesh network was installed to manage the basin. In the process of network construction, the characteristic of surrounding areas is considered about embodying secure service by investing the least expense. Besides, transmission environment analysis is performed such as LOS tests and reception level analysis, and transmission speed measurement to create safe service. Reception level in all places is confirmed among -55 dBm ~ -70 dBm, and data transmission speed proves more than 20 Mbps.

• Korean journal of applied entomology
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• v.16 no.2 s.31
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• pp.127-131
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• 1977

This experiment was conducted to evaluate the insect-proof netting, chemical sprays, application of attractants, fruit bagging and light trapping as the control methods of the fruit piercing moths in the orchards on reclaimed land in Sugyeri, Goksung, Chonnam Province, during June to October in 1976. The results are summarized as follows; 1. Insect-proof. netting effectively decreased fruit damage, compared as to the control, down to $9.4\%$ from $38.3\%$ in plum, $2.5\%$ from $53.0\%$ in peaches and $10.0\%$ from $29.0\%$ in grapes. 2. The control effects of chemicals varied significantly among the 7 insecticides tested: Deoclean, Naphthalene, and Thiometon were more effective to the fruit damages as low as $2.0\%,\; 3.6\%,\;and\;5.9\%$ respectively. while the fruit damage was rather high, $9.8\%$ for Demeton, $10.1\%$, for Takju +lead arsenate and $14.2\%$ for Padan. ,3. In the test with 7 attractants, the largest number of moths attracted and killed was 416.by Takju+brown sugar and the next was 307 by Takju+venegor while this number was 141 by mixed solution (see text) which is rather lower than expectation The fruit damage was lowest in Takju+honey and$5.2\%$, the next was $5.60\%$ for Takju+venegor and the highest was $12.0\%$, Takju alone. 4. Fruit bagging with polyethylene film effectively decreased the fruit damage from the inserts but brought about severe fruit rot and delay ripening. Meanwhile, paper bagging was less effective in preventing insects, resulting in $17.5\%$ fruit damage, however, gave no adverse effect other than slight Belay in ripening. 5. Light trapping was hardly expected to be a method of controlling these fruit piercing moths. However, the number of collected moths swarmed by electric light was 10.8 for can-descence, 0.95 for blue, and 0.22 for yellow light.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.1-12
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• 2021

Technologies for an MVDC(medium voltage direct current) distribution system are being considered as an effective alternative to overcome the interconnection delay issues of PV systems. However, the implementation of a DC distribution system might lead to economic problems because of the development of DC devices. Therefore, this paper deals with the scale of a PV plant based on its capacity and proposes hosting-capacity models for PV systems to establish a network to evaluate the feasibility of an MVDC distribution system. The proposed models can be classified as AC and DC distribution systems by the power-supply method. PV systems with hundreds of MW, dozens of MW, and a few MW can be categorized as large-scale, medium-scale, and small-scale models, respectively. This paper also performed modeling for an economic evaluation of MVDC distribution system by considering both the cost of AC and DC network construction, converter replacement, operation, etc. The profit was composed of the SMP and REC rate of a PV plant. A simulation for economic evaluation was done for the MVDC distribution system using the present worth and equal-principal costs repayment method. The results confirmed that the proposed model is a useful tool to evaluate economic issues of a DC distribution system.

• The KIPS Transactions:PartD
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• v.11D no.4
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• pp.885-892
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• 2004

Weibull distribution Iincluding Rayleigh and Exponential distribution is a typical model to estimate the effort distribution which is committed to the software testing phase. This model does not represent standpoint that many efforts are committed actually at the test beginning point. Moreover, it does not properly represent the various distribution form of actual test effort. To solve these problems, this paper proposes the Sigmoid model. The sigmoid function to be applicable in neural network transformed into the function which properly represents the test effort of software in the model. The model was verified to the six test effort data which were got from actual software projects which have various distribution form and verified the suitability. The Sigmoid model nay be selected by the alternative of Weibull model to estimate software test effort because it is superior than the Weibull model.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.9
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• pp.469-478
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• 2001

It is difficult to test a distributed system because of the task of controlling concurrent events,. Existing works do not propose the test sequence generation algorithm in a formal way and the amount of message is large due to synchronization. In this paper, we propose a formal test sequence generation algorithm using logical clock to control concurrent events. It can solve the control-observation problem and makes the test results reproducible. It also provides a generic solution such that the algorithm can be used for any possible communication paradigm. In distributed test, the number of channels among the testers increases non-linearly with the number of distributed objects. We propose a new remote test architecture for solving this problem. SDL Tool is used to verify the correctness of the proposed algorithm and it is applied to the message exchange for the establishment of Q.2971 point-to-multipoint call/connection as a case study.