• 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.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.609-614
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• 1999

Our present ability to work with video has not been confined to wired communication environment. This paper describes the new technological trend of wireless video communication. In wireless video communication, unlike wired network, several techniques are needed. At first, error robust video coding is essential. Due to characteristics of wireless channel, the system is exposed to more error prone environment. In addition, encoded video bit streams are vulnerable to the error because of the entropy coding. Recently many frameworks are developed to cope with this problem. We just explore the numerous robust video coding approaches with the viewing of error control. And more we discuss other on going research topics in this wireless video communication fields like low-power assumption design, trans-codec technique, and rate control schemes in brief.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.39-44
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• 2002

In this paper, in order to improve the performance of TCP short traffic application services in wireless Internet environments, the Split-ACKs (SPACK) scheme is proposed. In wireless networks, unlike wired networks, packet losses will occur more often due to high bit error rates. Therefore, each packet loss over wireless lints results in congestion control procedure of TCP being invoked at the source. This causes severe end-to-end Performance degradation of TCP. In this paper, to alleviate the TCP Performance, the SPACK method, split acknowledgement Packets in the base station, is proposed. Using computer simulation, the performance of TCP using SPACK is analysed and shows better performance than traditional TCP Protocol.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.737-744
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• 2012

Recently VoIP has provided voice(both wired and wireless from IP-based) as well as the transmission of multimedia information. VoIP used All-IP type, Gateway type, mVoIP etc. Wired and wireless VoIP has security vulnerabilities that VoIP call control signals, illegal eavesdropping, service misuse attacks, denial of service attack, as well as wireless vulnerabilities etc. from WiFi Zone. Therefore, the analysis of security vulnerabilities in wired and wireless VoIP and hacking incidents on security measures for research and study is needed. In this paper, VoIP (All-IP type, and for Gateway type) for system and network scanning, and, IP Phone to get the information and analysis of the vulnerability. All-IP type and Gateway type discovered about the vulnerability of VoIP hacking attacks (Denial of Service attacks, VoIP spam attacks) is carried out. And that is a real VoIP system installed and operated in the field of security measures through research and analysis is proposed.

• Journal of the Korean Society of Safety
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• v.27 no.1
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• pp.1-6
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• 2012

In crowded subway stations indoor air quality (IAQ) is a key factor for ensuring the safety and health of passengers. Since physical variables that describing IAQ such as the concentration of particulate, $CO_2$, VOCs and biological agents need to be closely monitored and controlled in multiple locations within subway stations and in remote sites, concept of web-based monitoring and control network using both wireless and wired media needs to be implemented. Connecting remote wireless sensor network and device (LonWorks) networks to the IP network based on the concept of VDN can provide a powerful, integrated, distributed monitoring and control performance. In this study, performance of wireless and wired network in VDN for monitoring and control of IAQ in subway stations is evaluated. Specifically, delay induced in wireless and wired networks, and data transmission rate are evaluated. A key parameter is identified in assuring safety and health of passengers in subway stations.

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.53-61
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• 2022

Accidents are steadily occurring due to machine defects and carelessness during LNG storage operations. In previous studies, an environmental sensor module capable of measuring pressure, temperature, gas concentration, and flow to detect danger in advance was developed and the response speed according to the amount of leaked gas was measured. This paper proposes the development of a wired and wireless communication module that transmits data measured by the environmental sensor module to embedded devices connected to wired and wireless networks of SPI, UART, and LTE. First, a data communication module capable of interworking with an environmental sensor is designed. Design a protocol between devices in the Local Control Part and wired and wireless protocols in the Local Control Part and Remote Control Part. Ethernet, WiFi, and LTE communication modules were designed, and UART and SPI channels that can be linked with embedded controllers were designed. As a result, it was confirmed through a UI (User Interface) that each embedded device transmits data measured by the environmental sensor module while simultaneously communicating on a wired and wireless basis.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.2
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• pp.115-122
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• 2008

Mostly used sensors have wired powering and two-way cable systems. It is difficult to employ wired sensor network in ubiquitous era because of a number of sensors and cables. Therefore, sensor networks move from wired systems to wireless systems for the future. However, the power source is a critical obstacle for wireless sensornodes. This research represents the new power source which supplies energy sensor node, maintains over 10 years, and thus replaces batteries with limit of lifetime. The system with piezo materials scavenges extra energies such as vibration and acceleration from the environment. Then it converts the scavenged mechanical energy to electrical energy for powering a sensor, a controller and a circuit for regulating voltage and transmitting sensor value. This study explains the properties of piezo material through theoretical analysis and experiments, and demonstrates powering sensor and transmitting data with stored energy (35mJ) for 14 sec. The developed system provides a solution to overcome the critical problem of making up wireless sensor networks.

• Journal of the Korean Society of Safety
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• v.29 no.1
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• pp.1-6
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• 2014

With increasing number of citizen using subway stations everyday, safety, health and comfort of passengers and occupants became an important social issue. Considering the fact that various physical variables and pollutants are related to indoor air quality (IAQ) which may cause health problem, IAQ need to be closely monitored and controlled in multiple locations in subway stations. This study is a continuation of the previous studies and delay induced in wireless-wired network is experimentally evaluated and the risk involved is assessed. In doing that, a key parameter is identified to be the network delay in different network media. Application of information-theoretic measure to assess the risk in network delay is then discussed. The idea is based on the general principles of engineering design and their applications to quantification of uncertainty in network delay. Experimental results show that more risk is involved in wireless data communication. Efficient and fast conversion of transmission data in both LonWorks/IP server and ZL converter is also noted.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.666-668
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• 2013

Wireless network environment is spreading due to the increase of using mobile devices, causing wireless network abuse. Network security and intrusion detection have been paid attention to wireless as well as wired existing and studied actively Snort-based intrusion detection system (Intrusion Detection System) is a proven open source system which is widely used for the detection of malicious activity in the existing wired network. Snort Wireless has been developed in order to enable the 802.11 wireless detection feature. In this paper, Snort Wireless Rule is analyzed. Based on the results of the analysis, present the traveling direction of future research.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.149-152
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• 2001

In general, the wireless services based on markup language and provided with wired network requires dedicated gateway system. But in this case, the serious problems such as security vulnerabilities, damage of contents are occurred to the application. In this paper, to improve above problems, we designed and implemented the new application named "Interacted Wired St Wireless Student Information System" using J2ME(Java 2 Micro Edition) platform and XML(eXtensible Markup Language) to transmit user data safely and support the system extendibility maintaining data format consistency respectively.pectively.