• Journal of Korea Society of Digital Industry and Information Management
• /
• v.5 no.1
• /
• pp.33-41
• /
• 2009

Network industry is complex combined with various fields of industry, such as communication, broadcast, construction, and home appliances. Moreover, it's fairly lucrative since the growth industry makes lots of added values, interacting with the others.The network industry, usually called 'Ubiquitous', connects some home appliances and makes an integrated system that you can use them with whenever and wherever. A demand for network security, however, has skyrocketed due to the relatively low safety. It's been expected that the market of home security is going to be grown up nearly 30 percent every year. Recently, analog surveilance cameras have been replaced with digital ones, and they will be providing stronger security services taking advantage of mutual interaction with related industies. In this paper, a mobile monitoring system for home security is proposed, which makes it possible to supervise all home appliances wherever you're, using the conventional wired/wireless network infra.

• ETRI Journal
• /
• v.39 no.3
• /
• pp.364-372
• /
• 2017

For the reliability of controllers in a software defined network (SDN), a dynamic and self-learning schedule method (DSL) is proposed. This method is original and easy to deploy, and optimizes the combination of multiple controllers. First, we summarize multiple controllers' combinations and schedule problems in an SDN and analyze its reliability. Then, we introduce the architecture of the schedule method and evaluate multi-controller reliability, the DSL method, and its optimized solution. By continually and statistically learning the information about controller reliability, this method treats it as a metric to schedule controllers. Finally, we compare and test the method using a given testing scenario based on an SDN network simulator. The experiment results show that the DSL method can significantly improve the total reliability of an SDN compared with a random schedule, and the proposed optimization algorithm has higher efficiency than an exhaustive search.

• Proceedings of the IEEK Conference
• /
• 2002.07c
• /
• pp.1713-1716
• /
• 2002

In this paper, we analyzed the performance of SDR-based dual-band CDMA system in wideband multipath channel employing RAKE receiver with MRC diversity. For the simulation of SDR-based dual-band CDMA system, we used digital If techniques, polyphase analysis filter bank as channelizer, where Remez exchange algorithm is employed in the realization of the digital filter.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.21 no.1
• /
• pp.49-57
• /
• 2016

A modular multilevel converter is widely adapted for a high-voltage direct current power transmission system. This study proposes a design methodology for a novel digital control that mitigates the negative effects caused by time delay, including communication transport delay for a modular multilevel converter. The modeling and negative effect of time delay are analyzed theoretically in a frequency domain, and its compensation methodology based on an inverse model is described fully with practical considerations. The proposed methodology is verified through several simulation results using a modular 21-level converter system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.3
• /
• pp.331-337
• /
• 2016

In this paper, we analyze performances of in-band full-duplex communication system and self-interference (SI) suppression methods in environment where there exists the SI signal. The SI has to be removed to achieve required error rate performance of the system in order - propagation domain, analog domain and digital domain. In propagation domain, the SI signal is attenuated by separating transmitted and received beams physically. In analog and digital domain, after reconstruction of the SI signal using channel estimates and transmit signal, the SI signal can be cancelled from the desired signal. In this paper, assuming that the SI signal can be sufficiently reduced in propagation domain, we demonstrate that the in-band full-duplex communication system can achieve the target error rate by suppressing the SI signal in order - analog and digital domain, based on channel estimates that can be obtained by the method of Least squares.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.24 no.4
• /
• pp.508-514
• /
• 2020

To implement the continuously evolving mobile communication standards such as Long Term Evolution (LTE) and 5G, the Software Defined Radio (SDR) concept provides great flexibility and efficiency. For many years, a high-end Digital Signal Processor (DSP) System on Chip (SoC) has been developed to support multicore and various hardware coprocessors. This paper introduces the implementation of the SDR platform hardware using TI's TCI663x chip. Using the platform, LTE transport channel is implemented by interworking multicore DSP with Bit rate Coprocessor (BCP) and Turbo Decoder Coprocessor (TCP) and the performance is evaluated according to various implementation options. In order to evaluate the performance of the implemented LTE transport channel, LTE base station system was constructed by combining FPGA main board for physical channels, SDR platform board, and RF & Antenna board.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.7
• /
• pp.1004-1012
• /
• 2022

This paper contains the implementation of a game as a feature of a package tour management application with the Digital Game-based Learning approach that helps tourists learn about tourism spots. The game is written in Java language for an Android smartphone that is designed to be integrated with Content Management System (CMS) to manage the game's contents and assets. The game contains one tourism spots introductory level and five quiz game levels with each having a reward (points) and punishment (time penalty) system, then summed the results to obtain the total score from all levels. The total score will determine a tourist's performance and be listed on an online leaderboard to increase competitiveness among tourists. The conducted performance evaluation of the game shows satisfactory results of 0.9 seconds of response time from the database to the game. Implementing the game presented in this paper will potentially reduce the burden of the tour guide and increase the efficiency of managing the tour group.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2021.11a
• /
• pp.72-73
• /
• 2021

As discussions of the International Maritime Organization for the introduction of the Marine Autonomous Surface Ship (MASS) began in earnest, discussions were conducted to prioritize cybersecurity (Cyber Risk Management) when developing a system to support MASS operation at the 27th ENAV Committee Working Group (WG2). Korea launched a technology development project for autonomous ships in 2020, and has been promoting detailed tasks for cybersecurity technology development since 2021. MASS operation in a digital maritime communication system environment requires network security of various digital equipment that was not considered in the existing maritime communication environment. This study introduces the basic concept of network security equipment to support MASS operation in the detailed task of cybersecurity technology development, and defines the network security equipment interface for MASS ship application in the basic stage.

• Journal of Communications and Networks
• /
• v.17 no.1
• /
• pp.12-20
• /
• 2015

Convolutional codes which are terminated by direct truncation (DT) and zero tail termination provide unequal error protection. When DT terminated convolutional codes are used to encode short messages, they have interesting error protection properties. Such codes match the significance of the output bits of common quantizers and therefore lead to a low mean square error (MSE) when they are used to encode quantizer outputs which are transmitted via a noisy digital communication system. A code construction method that allows adapting the code to the channel is introduced, which is based on time-varying convolutional codes. We can show by simulations that DT terminated convolutional codes lead to a lower MSE than standard block codes for all channel conditions. Furthermore, we develop an MSE approximation which is based on an upper bound on the error probability per information bit. By means of this MSE approximation, we compare the convolutional codes to linear unequal error protection code construction methods from the literature for code dimensions which are relevant in analog to digital conversion systems. In numerous situations, the DT terminated convolutional codes have the lowest MSE among all codes.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.12 no.2
• /
• pp.168-175
• /
• 1987

In this paper, a FFH-SS hybrid communication method using digital frequency synthesizer is proposed. This can simultaneously share the same frequency band with conventional band limited communication method without interference. In the experiment the selective hopping pattern is attained by some conbination of serial to parallel conversion of maximal code from pseudo random noise generater, and it is observed that the selective hopping band transition can be more easily achieved when the hop interval is nonuniform than it is uniform. Digital frequency synthesizer is now reported to have very poor spurious suppression ability below 50~60dB, the reason of this is observed from the experimental result, and the way of how to solve this problem is presneted.