• 방송공학회논문지
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• 제27권6호
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• pp.914-922
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• 2022

본 논문에서는 5G 이동통신망을 전송채널로 활용하는 4K UHD(Ultra High Definition) 상용 스트리밍 장치를 구성하고 성능시험 결과를 제시한다. 스트리밍 장치는 전송품질에 대한 모니터링 기능을 제공하는 RTP(Realtime Transport Protocol)를 전송 프로토콜로 적용하여 적응형 스트리밍 기능을 제공한다. 또한, 전송채널의 대역폭 변화에 최적화된 인코딩을 위하여 영상신호의 인코딩률을 조절할 수 있는 기능을 제공하며, 세 개의 5G 이동통신망과 인터페이스 되어 특정 채널에서의 장애 발생 시 다른 채널을 통해 스트리밍하는 자동 절체 기능도 제공한다. 성능시험을 통하여 4K UHD 신호에 대한 H.265 인코딩률은 48.69Mbps, Glass-to-Glass 평균 지연시간은 293.60ms, 립싱크를 위한 비디오 및 오디오의 평균 시간 차이는 120ms 수준임이 확인되어, 개발제품이 5G 이동통신망을 통한 4K UHD 스트리밍 장치로 적용될 수 있음을 보인다.

• Anatomy and Cell Biology
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• 제56권1호
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• pp.86-93
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• 2023

Age at death estimation has always been a crucial yet challenging part of identification process in forensic field. The use of human skeletons have long been explored using the principle of macro and micro-architecture change in correlation with increasing age. The clavicle is recommended as the best candidate for accurate age estimation because of its accessibility, time to maturation and minimal effect from weight. Our study applies pre-trained convolutional neural network in order to achieve the most accurate and cost effective age estimation model using clavicular bone. The total of 988 clavicles of Thai population with known age and sex were radiographed using Kodak 9000 Extra-oral Imaging System. The radiographs then went through preprocessing protocol which include region of interest selection and quality assessment. Additional samples were generated using generative adversarial network. The total clavicular images used in this study were 3,999 which were then separated into training and test set, and the test set were subsequently categorized into 7 age groups. GoogLeNet was modified at two layers and fine tuned the parameters. The highest validation accuracy was 89.02% but the test set achieved only 30% accuracy. Our results show that the use of medial clavicular radiographs has a potential in the field of age at death estimation, thus, further study is recommended.

• Journal of Information Technology Applications and Management
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• 제18권4호
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• pp.41-53
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• 2011

Trust prediction between users in social network based on the trust propagation assumes properties of transitivity and composability of trust propagation. But it has been hard to find studies which test on how those properties have been operated in real social network. This study aims to validate if the longer the distance of trust paths and the less the numbers of trust paths, the higher prediction error occurs using two real social network data set. As a result, the longer the distance of trust paths, we can find higher prediction error when predicting level of trust between source and target users. But we can not find decreasing trend of prediction error though the possible number of trust paths between source and target users increases.

• 전자공학회논문지B
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• 제31B권1호
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• pp.81-87
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• 1994

This paper describes the recognition of the printed Hanguel(Korean Character) using Neural Network. In this study, Neural network is used in only specific classification. Hanguel is classified globally by using template matching. Neural network is learned using the segmented grapheme. The grapheme of Hanguel is segmented using the structural method. Neural network is constructed, which is corresponded to the kind and the shape of graphemes. Each neural network is multi layer perceptron. The learning algorithm is the modified error back propagation using descending epsilon method. With five test character sets, the recognition rate of 94.95% is obtained.

• 디지털산업정보학회논문지
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• 제5권3호
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• pp.107-115
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• 2009

Traditionally, simulation method is used to test and evaluate the performance of communication protocol or functional elements for mobile communication service. In this paper, wireless network simulator is implemented using the C++ object-oriented programming language. This simulator can simulate wireless data services, like as ad-hoc networks, by considering the user's mobility. In this paper, the simulator includes network traffic model to reflect wireless data service and traffic source model to represent a user's mobility similar to real service environment and traffic characteristics can be reflected on the simulation, and also more accurate simulation results can be got through that. In addition, by using object-oriented techniques, new service feature or environment can be easily added or changed so that the developed mobile communication simulator can reflect the real service environment all the time. This simulator can be used in adjusting the characteristics of wireless data hosts following the mobility of the user, and also can be used in building new wireless ad-hoc network routing protocols.

• 한국항공운항학회지
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• 제20권4호
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• pp.7-13
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• 2012

This paper is to estimate aerodynamic coefficients needed to determine the missiles' controller design and stability from simulation data of Skid-to-Turn missile. Method of determining aerodynamic coefficients is to apply Neural Network and Recursive Least Square and results were compared and researched. Also analysing actual flight test data was considered and sensor noise was added. Estimate parameter of data with sensor noise added and estimated performance and reliability for both methods that did not need initial values. Both Neural Network and Recursive Least Square methods showed excellent estimate results without adding the noise and with noise added Neural Network method showed better estimate results.

• 상하수도학회지
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• 제21권3호
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• pp.305-314
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• 2007

Forecasting of water quality variation is not an easy process due to the complicated nature of various water quality factors and their interrelationships. The objective of this study is to test the applicability of neural network models to the forecasting of the water quality at Dalchun station in Han River. Input data is consist of monthly data of concentration of DO, BOD, COD, SS and river flow. And this study selected optimal neural network model through changing the number of hidden layer based on input layer(n) from n to 6n. After neural network theory is applied, the models go through training, calibration and verification. The result shows that the proposed model forecast water quality of high efficiency and developed web-based water quality forecasting system after extend model

• 품질경영학회지
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• 제30권3호
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• pp.168-185
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• 2002

A few recent international surveys reported that Korea ranks the top with respect to the high-speed information and communication network subscription per 100 people in the world. Such infrastructure has been bringing about broad changes in Internet service for both business and individual users. By conducting a questionnaire survey on a moderate size of sample proportional to the population of each region across country, we try to analyze what factors might explain the level of Internet service satisfaction with respect to security, searching, and convenience dimensions. According to the test results, several factors such as sex, age, kind of network lines, usage frequency, e-mail usage, e-shopping, online problem experience might explain the different levels of Internet service satisfaction in the high-speed Internet network. This study might shed a guidance to scholars conducting Internet-related studies and practitioners who plan information policies and business strategies.

• 조명전기설비학회논문지
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• 제28권10호
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• pp.27-36
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• 2014

Network analysis applications in energy management systems play a key role in the economic and reliable operation of power systems. In order to provide operators with useful network information, the accurate results of topology processing, state estimation, power flow, and contingency analysis must be simulated. This paper proposes a validation methodology of network analysis applications in energy management systems. The energy management systems was checked to ensure that it meets the originally specified functions based on the proposed methodology. In addition, the performance of state estimation is evaluated with the reference of the proposed methodology. The proposed methodology is being conducted by energy management systems and the Korean power systems have been utilized for the test systems.

• 한국전기전자재료학회논문지
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• 제14권1호
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• pp.84-92
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• 2001

In this papers, we proposed the new method in order to diagnosis aging state of transformers. For wavelet transform, Daubechies filter is used, we can obtain wavelet coefficients which is used to extract feature of statistical parameters (maximum value, average value, dispersion skewness, kurtosis) about each acoustic emission signal. Also, these coefficients are used to identify normal and fault signal of internal partial discharge in transformer. As improved method for classification use neural network. Extracted statistical parameters are input into an back-propagation neural network. The number of neurons of hidden layer are obtained through Result of Cross-Validation. The network, after training, can decide whether the test signal is early aging state, alst aging state or normal state. In quantity analysis, capability of proposed method is superior to compared that of classical method.