• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 A
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• pp.373-375
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• 1997

In this paper, we present IGBT VVVF inverters as a 1C1M propulsion system for electric car. These inverters are composed of high power IGBT's and controlled by compact control units. The control unit performs full digital control by using 32bit DSP and microcontroller. By using CAN-bus, high speed network is constructed within four control units. The stack is simplified and optimized by using plate bus and IGBT driver units of hybrid-type.

• 한국통신학회논문지
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• 제41권8호
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• pp.843-850
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• 2016

This paper introduces a novel modulation scheme for vehicular communication in taking advantage of existing LED lights available on a car. Our proposed 2-Phase Shift Keying (2-PSK) is a spatial modulation approach in which a pair of LED light sources in a car (either rear LEDs or front LEDs) is used as a transmitter. A typical camera (i.e. low frame rate at no greater than 30fps) that either a global shutter camera or a rolling shutter camera can be used as a receiver. The modulation scheme is a part of our Image Sensor Communication proposal submitted to IEEE 802.15.7r1 (TG7r1) recently. Also, a neural network approach is applied to improve the performance of LEDs detection and decoding under the noisy situation. Later, some analysis and experiment results are presented to indicate the performance of our system

• International Journal of Computer Science & Network Security
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• 제23권5호
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• pp.1-6
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• 2023

Text mining (TM) is most widely used to process the various unstructured text documents and process the data present in the various domains. The other name for text mining is text classification. This domain is most popular in many domains such as movie reviews, product reviews on various E-commerce websites, sentiment analysis, topic modeling and cyber bullying on social media messages. Cyber-bullying is the type of abusing someone with the insulting language. Personal abusing, sexual harassment, other types of abusing come under cyber-bullying. Several existing systems are developed to detect the bullying words based on their situation in the social networking sites (SNS). SNS becomes platform for bully someone. In this paper, An Enhanced text mining approach is developed by using Ensemble Algorithm (ETMA) to solve several problems in traditional algorithms and improve the accuracy, processing time and quality of the result. ETMA is the algorithm used to analyze the bullying text within the social networking sites (SNS) such as facebook, twitter etc. The ETMA is applied on synthetic dataset collected from various data a source which consists of 5k messages belongs to bullying and non-bullying. The performance is analyzed by showing Precision, Recall, F1-Score and Accuracy.

• 산경연구논집
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• 제10권8호
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• pp.55-65
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• 2019

Purpose - Recently, the fourth industrial revolution is rapidly progressing, and the central government-led innovation system is not able to flexibly cope with changes in science and the economy and society. To solve these problems, it is necessary for local governments, which can easily identify and flexibly respond to local sites, to become self-centered and ready to respond more quickly to massive changes. Through this research, this study investigated the awareness of the elements of Jeonnam Province's capabilities in the field of science and technology policy, the importance of R&D, and how network cooperation among the base institutions might affect performance. Research design, data, and methodology - In fact, the data used in this study only 115 people were polled, excluding five who did not respond to the necessary variables. The methods of the survey were sampled, and the means of the survey were investigated via a self-contained electronic file (e-mail). Statistical analysis, including hypothesis verification, was performed by SPSS 19. The regression analysis was used. Results - All factors significantly affect performance by dividing them into five sub-fields: R&D strategic establishment, R&D demand survey, R&D planning, R&D evaluation, and R&D project management. These results suggest the importance and need for local scientific technology policy capabilities. Besides, it was confirmed that the relationship between regional science and technology policy capabilities and performance was moderated by the recognition of the importance of science technology and network cooperation among the core organizations. Conclusions - As a result, independent variables regarding the capabilities of each scientific technology policy were found to be statistically significant and have a significant effect on performance. Second, the regression analysis has shown the moderation effects of R&D importance awareness between the capabilities of science and technology policies and their performance. On the other hand, a regression analysis showing that the capabilities of science and technology policies and network cooperation between the base regions were not significant, indicating that there is no effect of moderation of network cooperation between the base regions between the capabilities of science and technology policies and performance.

• The Journal of the Acoustical Society of Korea
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• 제20권4E호
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• pp.24-30
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• 2001

This paper describes a fast harmonic estimation, referred to as Delta Adjustment (DA), using a low resolution pitch. The presented DA method is based on modification of the Generalized Dual Excitation (GDE) technique[1] which was proposed to improve speech enhancement performance. We introduce the GDE technique and modify it to be suitable for low bit rate harmonic coding that uses only an integer pitch estimate. Unlike the GDE, the DA matches a frequency-warped version of the original spectrum that conforms to a fixed pitch at all harmonic bands. In addition, complexity and performance of the presented method are described in comparison with those of the conventional Fractional Pitch (FP) based harmonic estimation. Experimental results showed that the DA algorithm significantly reduces the complexity of the FP method while maintaining the performance.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.100-105
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• 2024

In this study, we propose an alternative approach using Artificial Neural Networks (ANN) for determining Mass Attenuation Coefficients (MAC) in various glass systems. This method takes into account the weights of glass compositions, density, and photon energy as input features. The ANN model was trained and tested on a dataset consisting of 650 data points and subsequently validated through a K-fold cross-validation procedure. Our findings demonstrate a high level of accuracy, with R² values ranging from 0.90 to 0.99. Additionally, the model exhibits robust extrapolation capabilities with an R² score of 0.87 for predicting MAC values in a new glass system. Furthermore, this approach significantly reduces the need for costly and time-consuming computations and experiments, making it a potential tool for selecting materials for effective radiation protection.

• Journal of Communications and Networks
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• 제8권1호
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• pp.28-37
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• 2006

State-dependent call admission control (SDCAC) is proposed to make efficient use of scarce wireless resource in a hierarchical wireless network with heterogeneous traffic. With SDCAC, new calls are accepted according to an acceptance probability taking account of not only cell dwell time but also call holding time and system state (i.e., occupied bandwidth). An analytical method is developed to calculate performance measures of interest, e.g., new call blocking probability, forced termination probability, over. all weighted blocking probability. Numerical results with not only stationary but nonstationary traffic loads are presented to show the robustness of SDCAC. It is shown that SDCAC performs much better than the other considered schemes under nonstationary traffic load.

• International Journal of Computer Science & Network Security
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• 제22권2호
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• pp.241-249
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• 2022

The current research attempts to measure the level of the acceptance of the Blackboard System (BBS) during the Corona crisis, and whether this is one of the reasons for the low use of the BBS at Al-Jouf University. To achieve this, the technology accepting model in the time of crisis (TAMTC) has been proposed to measure the degree of acceptance by students, which was then applied to a random sample of 339 of such. The results show a high level of student acceptance, despite their lower use of the system. The research also highlights the importance of upgrading e-courses and that the discontinuation of exam disqualification of students is secondary to their poor course attendance.

• 방송공학회논문지
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• 제13권5호
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• pp.696-706
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• 2008

본 논문에서는 IEEE 802.11e MAC의 모니터링과 제어가 가능하도록 제작된 QWLAN(Quality Wireless LAN) 보드를 장착한 네트워크에서 적응적인 고선명 스케일러블 비디오(Scalable Video Coding: SVC) 스트리밍 시스템의 성능을 보여준다. 제작된 MAC 보드에서 실시간으로 측정된 MAC 파라미터들을 이용하여 예측한 가용 대역폭에 적응적으로 추출할 비디오 데이터를 결정한다. 이를 위하여, 기존 SVC 비디오 패킷 추출방식보다 R-D(Rate-Distortion) 곡선 관점에서 우수한 추출방식을 제안한다. 제안하는 방법을 적용한 실험을 통하여, 무선 채널 상황에 빠르게 적응하여 비디오 스트리밍의 품질을 향상시킬 수 있음을 보여준다.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2009년도 정보통신설비 학술대회
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• pp.203-207
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• 2009

WiBro(Mobile WiMAX) has gained momentum as a top candidate to deliver the dream of full mobile wireless internet. To save cost and time in WiBro network design, simulation tool has to deploy powerful and useful analysis functions. If path loss model is more accurate, the reliability of analysis result of simulation tool will be much improved. So we emphasize on the importance of pathloss model in WiBro network design in this paper. For this, we introduce to three kinds of pathloss models(SUI, SCM, SCM-E) supposed properly models in WiBro RF (Radio Frequency) environment. Also we treat from basic theory to practical substance on the pathloss model to adopt WiBro network design/optimization. Finally, we describe about wireless network analysis tool named 'CellPLAN(R)' and techniques possible to improvethe accuracy of pathloss model.