• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.1
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• pp.237-253
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• 2019

For massive multiple-input multiple-output (MIMO) circumstances with time division duplex (TDD) protocol, pilot contamination becomes one of main system performance bottlenecks. This paper proposes an uplink pilot sequence assignment to alleviate this problem for spatially correlated massive MIMO circumstances. Firstly, a single-cell TDD massive MIMO model with multiple terminals in the cell is established. Then a spatial correlation between two channel response vectors is established by the large-scale fading variables and the angle of arrival (AOA) span with an infinite number of base station (BS) antennas. With this spatially correlated channel model, the expression for the achievable system capacity is derived. To optimize the achievable system capacity, a problem regarding uplink pilot assignment is proposed. In view of the exponential complexity of the exhaustive search approach, a pilot assignment algorithm corresponding to the distinct channel AOA intervals is proposed to approach the optimization solution. In addition, simulation results prove that the main pilot assignment algorithm in this paper can obtain a noticeable performance gain with limited BS antennas.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.841-844
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• 2005

As various mobile technologies, sensor technologies, remote control and infrastructure are developing and expectations on quality of life are increasing, a lot of researches and developments on home network technologies and services are actively on going. Until now, we focused on how to provide users with high-level home network services, while not many researches on home network security for guaranteeing safety are progressing, So, in this paper, we propose an access control model for home network that provides various users with home network services up one's characteristics and features, and protects home network systems from illegal accesses or intrusions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.733-736
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• 2006

As various mobile technologies, sensor technologies, remote control and network infrastructure are developing and expectations on quality of life are increasing, a lot of researches and developments on home network technologies and services are actively on going. Until now, home network is just beginning, and we are developing home network services necessary to users, incrementing easiness, however we need to research on the safety of home network system guaranteeing the easiness as the services are going actively. So, in this paper, we propose the access control mechanism for protecting the home network system against indoor/outdoor illegal accesses and unauthorized accesses.

• IE interfaces
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• v.9 no.3
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• pp.1-9
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• 1996

Competition in telecommunications field brings about change in attitudes toward technology development. It is no longer the case that technology development itself has merits but that technology development should be considered in terms of its economic concepts such as the cost-effectiveness concept. Techno-Economic study intend to incorporate the idea of economic efficiency into technology development and management so that economic potential of technologies is maximized. This paper categorizes the contents of techno-economic study in telecommunications and information technologies and suggests a framework of techno-economic study based on technology lifecycle and decision makers.

• Electronics and Telecommunications Trends
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• v.35 no.7
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• pp.23-35
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• 2020

In this paper, we introduce ETRI AI Strategy #3, "Leading Future Technologies of Network, Media, and Content." Its first goal is "to innovate AI service technology to overcome the current limitations of AI technologies." Artificial intelligence (AI) services, such as self-driving cars and robots, are combinations of computing, network, AI algorithms, and other technologies. To develop AI services, we need to develop different types of network, media coding, and content creation technologies. Moreover, AI technologies are adopted in ICT technologies. Self-planning and self-managing networks and automatic content creation technologies using AI are being developed. This paper introduces the two directions of ETRI's ICT technology development plan for AI: ICT for AI and ICT by AI. The area of ICT for AI has only recently begun to develop. ETRI, the ICT leader, hopes to have opportunities for leadership in the second wave of AI services.

• Electronics and Telecommunications Trends
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• v.35 no.6
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• pp.88-96
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• 2020

As the usability and value of personal information increase, the importance of privacy protection has increased. In Korea, the scope of the use of pseudonymized personal information has increased because of revisions to the law. In the past, security technologies were used to safely store and manage personal information, but now, security technologies focused on usability are needed to safely use personal information. In this paper, we look at issues related to the de-identification and re-identification of personal information. Moreover, we examine the standards and techniques related to the de-identification of personal information.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1320-1323
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• 2002

This paper reviews the Korean government’s selection process of core wireless communications technologies, and presents technology trends, perspectives and strategies of 5 core technologies to develop in wireless communications areas based on the mid term IT technology development plan(2002∼2004). Delphi Panel Method and Analytic Hierarchy Process(AHP) Analysis were adapted to select 30 core technologies in 9 strategic areas. Especially, 5 core wireless communications technologies out of 24 required technologies are selected: 4 G Core Technology, Broadband Wireless Access Network Technology, IMT-2000 Plus STP Technology, OBP Based Multimedia Satellite Communications Technology, Stratosphere Communications System Technology. Strategic national IT R&D program has been essential to continue success story of CDMA technology, and acquiring technology independency from advanced nations. In long term perspectives, a strategy of intensive investment with prudent selection onto core technologies should be deployed in the IT R&D programs. Also, the national IT R&D programs should be limited in the high risk & high returen areas where only government can afford the failures as well as better spill over effects are expected for the technology development and national economy. Korean industry has some strength in wireless communications technology area. Therefore, more policy concerns should be given into this area not only to secure present strength but also to explore better technology competitiveness.

• Journal of Communications and Networks
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• v.7 no.2
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• pp.135-143
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• 2005

This paper presents an investigation of satellite radio access technology for beyond IMT-2000 systems. Although we could not see any active role of a satellite system in the 3G networks, satellite system will provide strong advantages in future systems for certain applications. Because a satellite link has longer round trip delay than a terrestrial link, we need technologies that would make the satellite component especially efficient. After presenting the satellite radio interface of the 3G system, we suggest several points which need to be considered in the beyond 3G systems. We also suggest a few candidate technologies with various simulation results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.839-842
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• 2005

As various mobile technologies, sensor technologies, and remote control technologies are growing and quality of life is enhanced, researches and developments on home network are actively on going. Currently, some network service providers and construction corporations are going to provide home network service, but neither secure nor efficient, So, in this paper, we propose a security framework for providing various secure user authentication mechanisms and efficiently controlling services in home network. Namely, we are going to provide active home network security services with home gateway-based security policy, which locates on the gateway of each home.

• Electronics and Telecommunications Trends
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• v.35 no.4
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• pp.21-33
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• 2020

Single photon detector technologies have emerged as powerful tools in optical quantum information applications such as quantum communication, quantum information, and integrated quantum photonics. Owing to significant attempts in the previous decade at improving photon-counting detectors, several single photon detectors with high efficiency and low noise have been realized within the optical wavelength regime. In this paper, we provide an overview of current studies on single photon detectors operating at wavelengths from the ultraviolet to the infrared. In addition, we discuss applications of single photon detector technologies in quantum communication and integrated quantum photonics.