• 디지털산업정보학회논문지
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• 제4권3호
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• pp.69-75
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• 2008

The objective of this paper is to increase the performance by selecting the optimal value in outputs of two algorithms that are Generlized-Lagrange and LMS(Least Mean Square). This paper presents superior performance by mixed two of conventional algorithm arbitrary. Based on the analysis from various simulation, it is observed that proposed method is better performance in terms of practical WLL(Wireless Local Loop) environment.

• 디지털산업정보학회논문지
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• 제13권4호
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• pp.115-123
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• 2017

The mutual cooperation among nodes is very important because mobile nodes participating in MANET communicate with limited resources and wireless environment. This characteristic is important especially in environment that supports group communication. In order to support the secure multicast environment, it is important enough to affect performance to provide accurate authentication method for multicast group members and increase the integrity of transmitted data. Therefore, we propose a technique to provide the multicast secure communication by providing efficient authentication and group key management for multicast member nodes in this paper. The cluster structure is used for authentication of nodes in the proposed technique. In order to efficient authentication of nodes, the reliability is measured using a combination of local trust information and global trust information measured by neighboring nodes. And issuing process of the group key has two steps. The issued security group key increases the integrity of the transmitted data. The superiority of the proposed technique was confirmed by comparative experiments.

• 디지털산업정보학회논문지
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• 제10권4호
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• pp.89-96
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• 2014

MANET has been applied to a wide variety of areas because it has advantages which can build a network quickly in a difficult situation to build a network. However, it is become a victim of malicious nodes because of characteristics such as mobility of nodes consisting MANET, limited resources, and the wireless network. Therefore, it is required to lightweight attack detection technique which can accurately detect attack without causing a large burden to the mobile node. In this paper, we propose a multistage attack detection techniques that attack detection takes place in routing phase and data transfer phase in order to increase the accuracy of attack detection. The proposed attack detection technique is composed of four modules at each stage in order to perform accurate attack detection. Flooding attack and packet discard or modify attacks is detected in the routing phase, and whether the attack by modification of data is detected in the data transfer phase. We assume that nodes have a public key and a private key in pairs in this paper.

• 디지털산업정보학회논문지
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• 제10권4호
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• pp.143-150
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• 2014

A high power amplifier(HPA) has widely been used in wireless communications. In order to have a maximum power efficiency, the HPA uses a saturation domain having nonlinear characteristics, which generates nonlinear distortions to decrease the transmission efficiency. In order to solve this problem, various methods to linearize HPA have been reported until now, and the pre-distorter method is very attractive among them. In this paper, a new enhanced adaptive pre-distorter method was proposed to be applied for compensating nonlinear distortions of HPA. Through computer simulations as well as the analytical analysis, it could be shown that it is possible for both conventional adaptive pre-distorter and proposed adaptive pre-distorter, to be applied for linearizing HPA. Also, the simulations results demonstrated that the proposed adaptive pre-distorter may have faster convergence speed and better capability of compensating the nonlinear distortion than the conventional adaptive pre-distorter with nearly equal computation complexity.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.719-722
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• 2016

현재 산업 분야 전반에 걸쳐 다양한 IoT 기술들을 접목하려 하고 있다. 그러나 센서 디바이스, 게이트웨이, 네트워크 서버, 그리고 어플리케이션 서버로 구성되는 복잡한 IoT 시스템 구조는 구현 상의 어려움과 설치 비용의 증가를 초래하고 이로 인해 소규모 네트워크 환경이 필요한 산업 분야에서 IoT 도입을 저해하는 결과로 나타나고 있다. 이에 따라, 본 논문에서는 소규모/저비용의 IoT 환경이 필요한 산업분야에서 활용될 수 있는 시스템 구조를 제안 한다. 또한 RF433 모듈을 이용한 무선 센서 네트워크, 아두이노 윤을 활용한 게이트웨이, 그리고 APM (Apache, PHP, MySQL)을 적용한 어플리케이션 서버를 구현하고 센서 디바이스의 효율적인 전력관리 방안을 제시한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권9호
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• pp.3194-3210
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• 2022

Wall obstruction is the main factor leading to the non-line of sight (NLoS) error of indoor localization based on received signal strength indicator (RSSI). Modeling and correcting the path loss of the signals through the wall will improve the accuracy of RSSI localization. Based on electromagnetic wave propagation theory, the reflection and transmission process of wireless signals propagation through the wall is analyzed. The path loss of signals through wall is deduced based on power loss and RSSI definition, and the theoretical model of path loss of signals through wall is proposed. In view of electromagnetic characteristic parameters of the theoretical model usually cannot be accurately obtained, the statistical model of NLoS error caused by the signals through the wall is presented based on the log-distance path loss model to solve the parameters. Combining the statistical model and theoretical model, a hybrid model of path loss of signals through wall is proposed. Based on the empirical values of electromagnetic characteristic parameters of the concrete wall, the effect of each electromagnetic characteristic parameters on path loss is analyzed, and the theoretical model of regional path loss of signals through the wall is established. The statistical model and hybrid model of regional path loss of signals through wall are established by RSSI observation experiments, respectively. The hybrid model can solve the problem of path loss when the material of wall is unknown. The results show that the hybrid model can better express the actual trend of the regional path loss and maintain the pass loss continuity of adjacent areas. The validity of the hybrid model is verified by inverse computation of the RSSI of the extended region, and the calculated RSSI is basically consistent with the measured RSSI. The hybrid model can be used to forecast regional path loss of signals through the wall.

• 디지털산업정보학회논문지
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• 제19권2호
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• pp.69-78
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• 2023

In this paper, IO+5G dedicated hardware is developed and an AI device communication system equipped with a 5G is designed and tested. The AI device communication system equipped with a 5G receives the collected real-time images and the information collected from the IoT sensor in real time is to analyze the information and generates the risk detection events in the AI processing board. The event generated in the AI processing board creates a 5G channel in the dedicated hardware equipped with IO+5G. The created 5G channel delivers event video to the control video server. The 5G based dongle network enables faster data collection and more precise data measurement compared to wireless LAN and 5G routers. As a result of the experiment in this paper, the average test result of the 5G dongle network is about 51% faster than the Wi-Fi average test result in downlink and about 40% faster in uplink. In addition, when comparing the test result with terms of the 5G rounter to be set to 80% upload and 20% download, the average test result is that the 5G dongle network is about 11.27% faster when downloading and about 17.93% faster when uploading. when comparing the test result with terms of the the router to be set to 60% upload and 40% download, the 5G dongle network is about 11.19% faster when downlinking and about 13.61% faster when uplinking. Therefore, in this paper it describes that the developed 5G dongle network can improve the results by collecting data and analyzing it faster than wireless LAN and 5G routers.

• 한국전자파학회논문지
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• 제28권7호
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• pp.509-518
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• 2017

UAS(Unmanned Aircraft System) 또는 드론(drone)은 4차 산업혁명의 도래와 함께 급격히 성장할 것으로 예상되고 있으므로 미국을 비롯하여 EU, 중국, 일본 등에서는 국가 차원의 로드맵을 수립하고, UAS 관련 산업을 적극 육성하고 있다. 국내에서도 '16년도에 향후 성장 잠재력이 큰 무선통신 기반 유망 신산업 활성화를 위해 드론에는 2,670 MHz 주파수를 신규 추가로 공급하였다. 이에 본 연구에서는 UAS 국내외 산업동향, 핵심 전파기술과 주파수 확보 방안, 국내외 법제도 등을 분석하여 국내의 UAS 산업 활성화를 위한 방안을 제시하고자 한다.

• 전자통신동향분석
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• 제35권5호
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• pp.92-101
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• 2020

Artificial intelligence (AI) has become the hottest topic in information and communications technology (ICT) in recent years. Along with the advancement of AI technology, technologies such as big data, cloud, and high-speed wired and wireless communication are being applied to existing media areas in earnest, affecting all parts of the media value chain from content production to consumption. AI technology is now spreading across the media industry faster than any other industry. In the future, the gap between those with and without AI technology will widen, further deepening the polarization of the media ecosystem. Media intelligence, which combines media and AI technologies, is now perceived as essential, not optional. In this paper, we examine the current status of technology development and standardization by major domestic and foreign institutions on how AI is being utilized in the media industry. In addition, we discuss what technology should be developed to lead media intelligence.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2004년도 제5회 정기학술발표대회 논문집
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• pp.140-144
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• 2004

최근 물류 및 유통분야에서 혁명을 불러일으킬 것으로 예견되고 있는 RFID시스템이 국내의 건설산업 환경에도 큰 영향을 끼칠 것으로 예상되고 있다. 이미 $4\~5$년 전부터 국내 대형프로젝트에 바코드시스템을 활용한 노무인력관리 및 주요자재의 물류관리에 활용된바 있으나 바코드시스템이 갖고 있는 한계성으로 인해 건설현장에 그다지 성공적으로 정착하지 못하였다. 이를 극복하기 위한 한 방법으로 RFID시스템을 건설현장에 적합하게 개발 및 시범적용 해보았으며 본 연구를 통해 건설현장에 RFID시스템을 어떻게 적용을 하였고 어떠한 성과를 거두었는지에 대해 조사해 보았고, 향후 이러한 RFID시스템을 통해 적용 및 발전 가능한 방향에 대해 제시해 보았다.