• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1996.10a
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• pp.323-326
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• 1996

In this paper, we propose a new method of the communication system for cooperative behavior and control in a collective autonomous mobile robots. A communication function among the collective robots is essential to intelligent cooperation. In general, global communication is effective for small number of robots. However when the number of robot goes on increasing, this becomes difficult to be realized because of limited communication capacity and increasing amount of information to handle. And also the problems such as communication interference and improper message transmission occur. So we propose local communication system based on infrared sensor to realize the cooperative behavior and control as the solution of above problem. It is possible to prevent overflow of information and exchange of complex information by combining communicate a specific robot. At last we verify the effectiveness of the proposed communication system from example of cooperative behavior.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.3
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• pp.428-434
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• 2020

Recently, due to the development of ICT technology, changes to the convergence service platform of information systems are accelerating. Convergence services expanded to cyber systems with 5G communication, IoT, AI, and cloud are being reflected in the real world. However, the field of cybersecurity audit for responding to cyber attacks and security threats and strengthening security technology is insufficient. In this paper, we analyze the international standard analysis of information security management system, security audit analysis and security of related systems according to the expansion of 5G communication, IoT, AI, Cloud based information system security. In addition, we design and study cybersecurity audit checklists and contents for expanding security according to cyber attack and security threat of information system. This study will be used as the basic data for audit methods and audit contents for coping with cyber attacks and security threats by expanding convergence services of 5G, IoT, AI, and Cloud based systems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.11
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• pp.2035-2051
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• 2011

Theoretical Bit Error Rate (BER) and channel capacity analysis are always of great interest to the designers of wireless communication systems. At the center of such analyses people are often encountered with a high-dimensional multiple integrals with quite complex integrands. Conventional Gaussian quadrature is inefficient in handling problems like this, as it tends to entail tremendous computational overhead, and the principal order of its error term increase rapidly with the dimension of the integral. In this paper, we propose a new approach to calculate complex multi-fold integrals based on the number theory. In contrast to Gaussian quadrature, the proposed approach requires less computational effort, and the principal order of its error term is independent of the dimension. The effectiveness of the number theory based approach is examined in BER and capacity analyses for practical systems. In particular, the results generated by numerical computation turn out in good match with that of Monte-Carlo simulations.

• International Journal of Computer Science & Network Security
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• v.23 no.3
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• pp.139-143
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• 2023

In this article we propose using mathematical models of signals in wireless communication systems with autocorrelation reception of modulated ultra-wideband signals. For the transmission of information content, the method of positional-time coding is used, in which each information bit is encoded by hundreds of ultrashort pulses that arrive within a certain sequence. Comparative analysis has shown that the best noise immunity of the systems considered in this paper is the communication system, which uses the time separation of the reference and information signals.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.395-398
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• 2018

we propose a design method and process for hardware and software of hybrid V2X communication systems that support both C-ITS communication protocol and Legacy LTE communication technology. The hybrid V2X communication systems support multiple communication technologies of WAVE and LTE, in which WAVE supports multiple channels, so that it is designed to transmit road information such as LDM and positioning correction information to an autonomous vehicle in real time.

• Journal of information and communication convergence engineering
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• v.10 no.4
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• pp.337-342
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• 2012

The medical industries are integrated with information technology with mobile devices and wireless communication. The advent of mobile healthcare systems can benefit patients and hospitals, by not only providing better quality of patient care, but also by reducing administrative and medical costs for both patients and hospitals. Security issues present an interesting research topic in wireless and pervasive healthcare networks. As information technology is developed, many organizations such as government agencies, public institutions, and corporations have employed an information system to enhance the efficiency of their work processes. For the past few years, healthcare organizations throughout the world have been adopting health information systems (HIS) based on the wireless network infrastructure. As a part of the wireless network, a mobile agent has been employed at a large scale in hospitals due to its outstanding mobility. Several vulnerabilities and security requirements related to mobile devices should be considered in implementing mobile services in the hospital environment. Secure authentication and protocols with a mobile agent for applying ubiquitous sensor networks in a healthcare system environment is proposed and analyzed in this paper.

• Journal of Korea Multimedia Society
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• v.14 no.3
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• pp.471-479
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• 2011

The world has witnessed a phenomenal growth in information and communication technologies (ICT). The development of new broadband communication services convergence of telecommunication with computers and recent developments in the field of communication protocol have fostered challenges as well as offerings in the wide-ranging use of ICT to support the creation of dynamic and interactive teaching and learning environment. By emergence of ICT, most of education and training institutions are struggling to integrate ICT and education and training systems. It is so important to apply proper delivery systems for utilization of the computerized teaching and learning contents in the classrooms. It will be a preliminary activity for building open and flexible distance teaching and learning systems in developing countries. In this paper, we would like to suggest and recommend the proper delivery systems for utilization of the computerized teaching and learning contents in the classrooms for education sector reform in developing countries.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.5
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• pp.525-536
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• 2014

Recently, the first generation of mass production of FinFET-based microprocessors has begun, and scaling of FinFET transistors is ongoing. Traditional capacitance and resistance models cannot be applied to nonplanar-gate transistors like FinFETs. Although scaling of nanoscale FinFETs may alleviate electrostatic limitations, parasitic capacitances and resistances increase owing to the increasing proximity of the source/drain (S/D) region and metal contact. In this paper, we develop analytical models of parasitic components of FinFETs that employ the raised source/drain structure and metal contact. The accuracy of the proposed model is verified with the results of a 3-D field solver, Raphael. We also investigate the effects of layout changes on the parasitic components and the current-gain cutoff frequency ($f_T$). The optimal FinFET layout design for RF performance is predicted using the proposed analytical models. The proposed analytical model can be implemented as a compact model for accurate circuit simulations.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1752-1755
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• 2002

The world wide web (WWW) already accounts f3r more Internee network traffic than any other application, including il and simple file transfer. It is also a collaborative technology in a weak sense of the word - it allows people to share information. Synchronous collaboration is where an interactive activity is simultaneous and in teal-time. Computer based real time collaborative systems like shared whiteboards. collaborative editor etc. are only beginning to emerge recently. These applications invoking more than two users exchanging information, require Multicast communication. Multicast communication is a transmission mode that is now supported by a variety of local and wide area networks. Multicasting enables multiparty communication across a wide area to sparsely distributed groups by minimizing the network load. Multicasting itself is one of the key technologies in the nut generation of the Internet This paper describes the technical issues from the aspect of multicast communication and its reliability in synchronous collaborative application.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.4
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• pp.1042-1058
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• 2024

Terahertz (THz) communication is becoming a key technology for future 6G wireless networks because of its ultra-wide band. However, the implementation of THz communication systems confronts formidable challenges, notably beam splitting effects and high computational complexity associated with them. Our primary objective is to design a hybrid precoder that minimizes the Euclidean distance from the fully digital precoder. The analog precoding part adopts the delay-phase alternating minimization (DP-AltMin) algorithm, which divides the analog precoder into phase shifters and time delayers. This effectively addresses the beam splitting effects within THz communication by incorporating time delays. The traditional digital precoding solution, however, needs matrix inversion in THz massive multiple-input multiple-output (MIMO) communication systems, resulting in significant computational complexity and complicating the design of the analog precoder. To address this issue, we exploit the characteristics of THz massive MIMO communication systems and construct the digital precoder as a product of scale factors and semi-unitary matrices. We utilize Schatten norm and Hölder's inequality to create semi-unitary matrices after initializing the scale factors depending on the power allocation. Finally, the analog precoder and digital precoder are alternately optimized to obtain the ultimate hybrid precoding scheme. Extensive numerical simulations have demonstrated that our proposed algorithm outperforms existing methods in mitigating the beam splitting issue, improving system performance, and exhibiting lower complexity. Furthermore, our approach exhibits a more favorable alignment with practical application requirements, underlying its practicality and efficiency.