• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.2
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• pp.73-80
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• 2009

Security is critically important for ubiquitous sensor networks that are usually used for the military and serveillance in environments that are opened to attacks, such as, eavesdroping, replay attacks of abnormal messages, forgery of the messages to name a few. ZigBee has emerged as a strong contender for ubiquitous sensor networks. ZigBee is used for low data rate and low power wireless sensor network applications. To deploy ubiquitous sensor networks, the collected information requires protection from an adversary over the network in many cases. The security mechanism should be provided for collecting the information over the network. However, the ZigBee protocol has some security weaknesses. In this paper, these weaknesses are discussed and a method to improve security aspect of the ZigBee protocol is presented along with a comparison of the message complexity of the proposed security protocol with that of the current ZigBee protocol.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.86-93
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• 2010

This paper presents the guideline for enhancing the reliability and availability of SAS with IEC 61850 based IEDs in real power system. The IEC 61850 standard communication networks and systems allow utilities to consider new designs for substations applicable both new substation and refurbishments. The existing solutions are based on hardwired interface between the primary substation equipment and the secondary protection, monitoring, control and recording devices. All over the world, lots of projects at different stages of realization have been reported during the last year leading to a rapid maturation of the associated technologies. At present, IEC 61850 is becoming a popular communication standard for the substation automation system.

• The Transactions of the Korea Information Processing Society
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• v.1 no.4
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• pp.479-489
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• 1994

At the present time, it is an important problem that we are to select a transmission line code for the very-high speed optical transmission system which can confidentially transfer the original information signal sequence efficiently, as it is to be the large capacity and the economization for the optical digital transmission system to transfer the information signal sequence at the very-high speed. Therefore, this paper is to select first the proper transmission line codes for the high speed(more than Mb/s) optical transmission system of the proposed two-level unipolar transmission line codes up to date, and to decide a mBIZ (m Binary with One Zero insertion) code as an optimal transmission line code for the very-high speed optical transmission system, resulting from analyzing the performance at the requirements of the transmission line code, such as the maximum consecutive identical digits, the transmission delay time, the increasing rate of clock, the mark rate, the circuit complexity, the supervision of transmission line error, and power spectrum among the selected transmission line codes.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.12
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• pp.1329-1336
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• 2015

Due to the advances in hardware technologies for low-power CMOS cameras, there have been various researches on wireless video sensor network(WVSN) applications including agricultural monitoring and environmental tracking. In such a system, its core technologies include video compression and wireless transmission. Since data of video sensors are bigger than those of other sensors, it is particularly necessary to estimate precisely the traffic after video encoding. In this paper, we present an estimation method for the encoded video traffic in WVSN networks. To estimate traffic characteristics accurately, the proposed method first measures complexities of frames and then applies them to the bit rate estimation adaptively. It is shown by experimental results that the proposed method improves the estimation of bit rate characteristics by more than 12% as compared to the existing method.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.5
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• pp.783-788
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• 2011

Most management systems that are currently in place to monitor the safety of bridges - working in conjunction with a wireless sensor network - are based on a wired infrastructure. Not only do these wired systems expensive to install, but they are expensive to replace or repair should a problem occur with the system while in operation. In an effort to address these problems, there have been many researches that attempted to use a wireless sensor network for the existing wired measurement system. However, they have been met with difficulty due to the problems of power and synchronization in actually bringing the management system to the bridges as a commercial system. This paper proposes a bridge management system based on WSN (Wireless Sensor Network) which uses wireless LAN technology. The system was tested using a testbed and when the obtained data were compared to the data collected using the existing wired counterpart it was found that they were almost the same.

• Journal of the Korea Society of Computer and Information
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• v.19 no.6
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• pp.49-59
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• 2014

Recently, wireless sensor networks(WSNs) are widely used for intrusion detection and ecology, environment, atmosphere, industry, traffic, fire monitoring. In this paper, an energy efficient clustering algorithm is proposed. The proposed algorithm forms clusters uniformly by selecting cluster head that optimally located based on receiving power. Besides, proposed algorithm can induce uniform energy consumption regardless of location of nodes by multi-hop transmission and MST formation with limited maximum depth. Through the above, proposed algorithm elongates network life time, reduces energy consumption of nodes and induces fair energy consumption compared to conventional LEACH and HEED. The results of simulation show that the proposed clustering algorithm elongates network life time through fair energy consumption.

• Journal of the Korea Society of Computer and Information
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• v.13 no.2
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• pp.203-210
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• 2008

Home networking has been noticed as a key technology for the home automation because it is possible to remotely monitor and control the in-house appliances and devices through the network. Wireless home networking method is easily applied to the conventional houses compared to the wired home networking method because of low cost and small effort due to no extra wired works. Especially, home networking using the ZigBee protocol is one of the most attractive technologies in the wireless networking area because of its low cost and low power consumption characteristics. However, there are a lot of practical problems to be solved in implementing the ZigBee module and constructing the wireless network. In this paper, one of the practical structures of the hardware and software modules for implementing the ZigBee protocol is proposed. Moreover, problems in constructing the home networking with the proposed ZigBee module are introduced, and the effective solutions to solve these problems are described through various tests.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.159-169
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• 2016

The current railway control system in Korea is comprised of signaling, electric rail power, communication, and maintenance systems that are independent of each other. Further, these systems have different mediums and protocols for transmitting the field equipment data to the central control system. The Safety Supervision System has as its purpose the collecting of safety-related data from each system to predict and prevent accidents, this system utilizes standard protocol. Safety-related data need to be collected from field data transmission devices of the existing control system, the data should be collected without affecting the communication of the existing system. In this study, sniffing skill, which is typically used for network traffic monitoring or security, is used to collect data. The problems arising from the use of sniffing devices are noted, and the Packet Conversion Node is proposed as a solution to the problems. Further, functional and performance testing were completed for the prototype, and the software architecture and packet conversion process were verified.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.3
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• pp.381-387
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• 2011

Measurement controller that acquire and control and observe data from scattering sensors is organic with central control room. Therefore, measurement controller is efficient wireless network than wire network. But, serious problem is happened in security from outside if use wireless network. Therefore, this paper proposed suitable MS-WP cryptographic system to measurement control wireless network to augment network efficiency of measure controller. Result that implement proposed MS-WP cryptographic system by chip level and achieve a simulation, confirmed that 130% processing rate increase and system efficiency are increased double than AES algorithm. Proposed MS-WP cryptographic system augments security and is considered is suitable to measurement controller because that low power is possible and the processing speed is fast.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.2
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• pp.129-136
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• 2018

The IEC 61850 communication standard is used worldwide, and within the country the new substation is built as a digital substation based on IEC 61850 from 2013, after field tests and R&D from 2007. Research on the development of digital substation operating system has been conducted mainly in large domestic companies, so the IED power application equipment for LCP are developed. However, there is still a lack of research in the field of systems that can accommodate all the field devices used for legacy substation and new digital substation. In this paper, we developed the 48VDC input modules and the 125VDC output modules which can construct proposed field information processing modules to IEC 61850 based type, and verified the field applicability from the state monitoring and control operation tests by using IEC 61850 client authentication program and Wireshark.