• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.2
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• pp.306-317
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• 1997

This ppaer presents a bit-rate conversion system for efficient communications between 3 channel CVSD systems with different bit-rates. The proposed conversion system is implemented in the digital domain and specially, the conversion problem between 32 Kbps and 16 Kbps CVSD systems is studied. The conventional conversion system implemented in the analog domain allows signals to be easily degraded by external noises. To overcome this problem, a digital CVSD bit-rate conversion system robust to external noises is developed. the new systemdecodes CVSD bit sequences and converts sampling rates of decoded signals, then encodes signals at target bit-rates. Since linear phase property does not matter in this application, instead of FIR filters a IIR filter is employed to reduce the system complexity. Therefore, a 3 channel digital CVSD bit-rate conversion system was successfully real-time implemented using a general purpose DSP. In addition, conversion problems with unkown time constants were experimented and good experimental results were obtained.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.25 no.5 s.216
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• pp.17-21
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• 2007

• Proceedings of the Korea Database Society Conference
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• 1998.09a
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• pp.3-48
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• 1998

Drivers for Increased Need for Digital Content ■ Falling cost of computing -Multimedia capability at reasonable cost ■ Decrease in digital storage cost -Magnetic, optical and tape -Cost of digital storage decreases 40％ / year ■ World Wide Web users explosion and falling cost of communications -17M web servers(1/97) -Number of users doubles every 6 months - Network bandwidth triples every year(omitted)

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.10
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• pp.4923-4939
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• 2019

In this paper, a secure transmission scheme based on the artificial noise is proposed for D2D communications underlaying the full-duplex cellular network, and a secure power allocation scheme to maximize the overall secrecy rate of both the cellular user and D2D transmitter node is presented. Firstly, the full-duplex base station transmits the artificial noise to guarantee the secure communications when it receives signals of cellular uplinks. Under this secure framework, it is found that improving the transmission power of the cellular user or the D2D transmitter node will degrade the secrecy rate of the other, although will improve itself secrecy rate obviously. Hence, a secure power allocation scheme to maximize the overall secrecy rate is presented subject to the security requirement of the cellular user. However, the original power optimization problem is non-convex. To efficiently solve it, we recast the original problem into a convex program problem by utilizing the proper relaxation and the successive convex approximation algorithm. Simulation results evaluate the effectiveness of the proposed scheme.

• International Journal of Computer Science & Network Security
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• v.23 no.12
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• pp.137-144
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• 2023

The relevance of the research topic lies in the necessity to use social networks as innovative tools of marketing communications. A wide audience and the ability to segment the market for a specific consumer determine the construction of a corporate strategy, which will be based on using the social networking approach. The spread of the global coronavirus pandemic has led to the rapid development of remote communication channels between the company and the customer. The issue of using marketing tools in social networks acquires the most urgent importance in the modern world of the introduction and implementation of the company's marketing strategies. The purpose of the academic paper is to study the use of social networks as features of implementing the marketing campaign. Social networks are the result of the development of digital technologies and the processes of creating an information society involved in the digital space. The objectives of the research are to analyse the opportunity of using social networks as a tool for marketing communications and their implementation at the level of its widespread use by enterprises and establishments. It is significant to create an advertising campaign by defining the target audience and outlining the key aspects, on which the company is focused. The research methodology consists in determining the theoretical and methodological approaches to the essence of introducing social networks and their practical importance in the implementation of marketing activities of companies. The obtained results can significantly improve the quality of functioning of modern enterprises and organizations that plan to master a new market segment or gain competitive advantages in the existing one. The academic paper examines the essence of social networks as a tool of marketing communications. The key principles of the development of digital social platforms were revealed. The quality of implementing the advertising campaign in the social network was studied, and further prospects for the development of using social networks as a component of the marketing strategy were outlined. Therefore, the academic paper analyses the problems of using social networks as a marketing tool.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11b
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• pp.1289-1292
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• 2003

현재 인터랙티브 서비스는 MHP와 같은 표준 스펙에서 다양하게 제안되어 시도되고 있으나, 모두 종단간 프로토콜이며, 네트워크 차원에서의 효율적인 서비스 지원을 위한 연구는 찾아보기 어렵다. 본 논문에서는 인터랙티브 서비스와 개인화 서비스를 네트워크 차원에서 지원하기 위하여, OPES 기반의 인터랙티브 방송 네트워크 구조를 제안하였다.

• Journal of Communications and Networks
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• v.12 no.6
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• pp.558-567
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• 2010

In this paper, we analyze the capability of satellite broadcasting systems to offer different levels of quality of service (QoS). We focus on the European telecommunications standards institute satellite digital radio and digital video broadcasting satellite handheld (DVB-SH) standards, which have recently been proposed for satellite broadcasting communications. We propose a strategy to provide different levels of QoS for the DVB-SH standard on the basis of an extension of the interleaving scheme, referred to as molded interleaver, which supports low latency service requirements for interactive services. An extensive analysis based on laboratory measurements shows the benefits of this solution. We also present a multilevel coding (MLC) scheme with multistage decoding designed for broadcasting communications as an alternative to the existing standards, where services with different levels of QoS are provided. We present a graphical method based on mutual information for the design and evaluation of MLC systems used for broadcasting communications. Extensive simulations for a typical satellite channel show the viability of the proposed MLC scheme. Finally, we introduce multidimensional constellations in the proposed MLC scheme in order to increase the number of different protection levels.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.6
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• pp.1310-1316
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• 2014

The IMO has recommended on VHF digital communications operation for sailing ships from 2017. And ships more than 5 tons is obliged to digital communications by fishing Vessels Act and Vessel Safety Act in domestic. The owner of all vessel is equipped to the automatic position reporting device in accordance with the Notice of the Ministry of Oceans and Fisheries to regulations, It shall be ensure to navigations safety and in order to respond quickly in the event of maritime accidents on all vessels. The info-communications station of fishery is operating the automatic position reporting system using the VHF DSC in east sea from 2012, Continuously, which is underway the install plan in south sea and yellow sea. But this plan is very difficult, because of propagation environment is poor on account of complicated coastline and many islands. This paper has analyzed the propagation coverage for position setting of coast station in south sea and the traffic zone set up by compare with RSSI and methode of navigation tracking by VMS.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.104-109
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• 2016

A technology of GEO satellite communications starts from Koreasat program in Korea. Payload equipment of EQM Ku and Ka band transponders had been developed and space-qualified Ka band payload in COMS was successfully launched in June, 2010. For the purpose of military communications, Dehop-Rehop transponder was developed in Koreasat5 as ANASIS system and DAT(Digital Active Transponder) and DCAMP(Digital Channel AMPlifier) transponders are now under development. In this paper, from the study of military satellite communications trend, a direction of military communication satellite is suggested based on the current GEO SATCOM technologies in Korea. Considering the limit of frequency resources, a technology of battlefield adaptive transponder with medium capacity against high moveable jamming tactics would be efficient for the future military SATCOM system. Mid-sized military satellites with frequency hopping and mid-capacity transponders can be a solution of vitalizing the GEO satellite programs.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.4
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• pp.317-323
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• 2001

DICOM(Digital Imaging and Communications in MediCine), standard of medical image operation, present the methods for communications and Storage of Medical Image. medical image acquired from patient in hospital made DICOM files. this paper purposes design and implementation methodologies of a web-based medical information system that consists of DICOM (Digital Imaging and Communications in Medicine) databases and functional components of a web server in order to support the access of medical information with Intemet web browser. we store the patient and image information to database using reading the group and element oJ DICOM file. we made file transfer module by implementing DICOM Store service, in result, we can transfer DICOM file to IF based host or computer. We compose web component of communications and Storage service, user be used DICOM Service by web Browser.