• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.7
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• pp.564-571
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• 2013

Wireless network has been used in many applications due to its advantages such as convenience, mobility, productivity, easy deployment, easy expandability and low cost. When it comes to stability, wireless network still shows its limitation which makes it difficult to be used for real-time control system. One of the first problems of using wireless network for control system is clock synchronization. There have been synchronization schemes proposed for wired networked control system as well as wireless network. But these should not be applied directly in wireless network control system. In this paper, we point out the importance of clock synchronization in wireless network control system. Then based on the characteristic of wireless networked control system, we propose a clock synchronization scheme for it. Furthermore, we simulate our scheme and compare with previous synchronization scheme in wired and wireless environments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.748-751
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• 2004

In this paper, we discuss about wireless Internet security. The past few years have seen unprecedented growth in the number of wireless user, applications, and network access technologies. Wireless Internet is similar to wired internet, but it has some constrained wireless environment. So many internet technologies for wireless are developing now. There are WAP(Wireless Application Protocol) and WPKI. WAP(now version 2.0) is a protocol specification for wireless communication networks. it provides an application framework and network protocols for wireless devices such as mobile telephones, PDAs and internet technologies. In this paper some analysis of security(e.g. digital signature or encryption) for wireless internet are performed.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.5
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• pp.1063-1075
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• 2019

In recent years, industrial automation has been established and WISN (Wireless Industrial Sensor Network) has been introduced for efficient system management. By introducing WISN, many engineering costs have been reduced and process processors have been optimized. And communication flow using wireless is increasing. An empirical study on industrial wireless sensor networks is actively conducted, but there are few security studies on them and they are exposed to such threats. If there is a problem with the standard of the wireless communication protocol itself, the device that is certified according to the standard may also be subject to security threats including problems. We analyze security functions and threats of ISA 100.11a and WirelessHART protocol stack based on standards. Procedures for distributing the security key are not provided or it is vulnerable using the Global Data Link key when the device enters the network. This paper presents the problems of the standard itself and presents the security requirements accordingly.

• Journal of the Korea Society of Computer and Information
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• v.13 no.5
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• pp.85-94
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• 2008

As a variety of wireless network services, such as WLAN, WiBro, cdma2000, and HSDPA, are provided and the range of users' choices for the wireless services are broaden, MCoA (Multiple Car-of Address) concepts that enable users to use wireless interfaces simultaneously have been presented in IETF MONAMI6 WG. Through this scheme, users can access several networks simultaneously by using multiple wireless interfaces. Such various wireless connection technologies continue to advance as they are connected and integrated to All-IP-based core network, and at the same time, heterogeneous networks are being managed overlaid according to the coverage of the wireless connection technologies. Under such circumstances, needs for an integrated architecture have arisen, and thus Wireless service framework is required that effectively manages heterogeneous networks which coexist with next generation's networks for 4G. In this paper, a wireless service framework is suggested in the consideration of current wireless service environment, and the framework covers the schemes to minimize the packet loss caused by handover, and also modified Multiple Care-of Address that helps to select most effective network by considering characteristics of various interfaces as well as users' preferences.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.3 no.1
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• pp.26-51
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• 2009

In this paper, we propose an empirical framework for modeling and emulating interference in multi-hop wireless ad-hoc networks. Wireless interference causes wide variation in the frame delivery rate at a link, and thus we cannot represent the state of the link with only two states, connected state and disconnected state, as in wired networks. We first investigate wireless interference in detail, in order to accurately calibrate the interference and identify its underlying attributes, and then we simulate the diverse occurrences and effects of interference, after incorporating the scheme into a simulation tool. Based on these observations, we devise a modeling and simulation framework with several control parameters, and perform an extensive set of simulation studies. The simulation results indicate that the proposed framework enables us to examine various attributes of wireless interferences and their effects on wireless network protocols and systems.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.32-38
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• 2020

The deployment of geographically distributed wireless sensors has greatly elevated the capability of monitoring structural health in social-overhead capital (SOC) public infrastructures. This paper deals with the utilization of a distributed mobility management (DMM) approach for the deployment of wireless sensing devices in a structural health monitoring system (SHM). Then, a wireless sensing mechanism utilizing low-energy adaptive clustering hierarchy (LEACH)-based clustering algorithm for smart sensors has been analyzed to support the seamless data transmission of structural health information which is essentially important to guarantee public safety. The clustering of smart sensors will be able to provide real-time monitoring of structural health and a filtering algorithm to boost the transmission of critical information over heterogeneous wireless and mobile networks.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.1
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• pp.120-130
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• 2009

In recent years, many mobile wireless communication devices and applications have been deployed on the planet. The mobile multi-hop wireless network models appeared to provide means to access to networks where few infrastructure exists. However, the mobile multi-hop wireless networks have weaker points in attacks and intrusions than the wired and one-hop wireless networks. In this paper, the secure routing issues in most mobile multi-hop wireless network models are surveyed in depth. The state-of-the-art technologies and research activities are explained. Finally, the issues and technologies for the secure routing specific to a maritime network model are sufficiently discussed as conclusions.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.243-245
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• 2004

This paper proposes design and implementation for Seamless Handoff method between adapters in a system environment where both wired and wireless adapters are present First of all, by settingLayer 2 address of wired adapter to Layer 2address of wireless adapter, then generate virtual adapter on the above layer to make these two adapters operate on an IP address. Under the condition, when wired communication via the wired adapter gets disconnected while in service, wireless handoff occurs by mapping information on the wireless adapter to the virtual adapter. According to the method proposed in this paper, continuous session can be obtained even when handoff between wired and wireless adapters occurs at lower level in an application where both IP address and Port address are used to maintain session since If address does not change.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.3
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• pp.324-340
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• 2010

Video streaming service over wireless networks is a challenging task because of the changes in the wireless channel conditions that can occur due to interference, fading, and station mobility. To provide an efficient wireless video streaming service, the rate adaptation scheme should improve wireless node performance and channel utilization. Moreover, the quality adaptation scheme should be considered at the streaming application. To meet these requirements, we propose a new cross-layer design for video streaming over wireless networks. This design includes the rate and quality adaptation schemes. The rate adaptation scheme selects the optimal transmission mode and resolves the performance anomaly problem. Based on performance improvement by the proposed rate adaptation scheme, our quality adaptation scheme improves the quality of video streaming. Through performance evaluations, we prove that our cross-layer design improves the wireless channel utilization and the quality of video streaming.

• Journal of Korea Multimedia Society
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• v.19 no.11
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• pp.1871-1877
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• 2016

In this paper, a Wireless USB (WUSB) protocol is adopted for development of ASMD (Adaptive Source Multi Device) N-screen wireless services. WUSB is the USB technology merged with WiMedia PHY and Distributed-MAC (D-MAC). However, the current WUSB protocol can't provide seamless N-screen streaming services to moving WUSB devices in home network environment. Therefore, to provide the ASMD N-screen services through WUSB based on D-MAC protocol, a channel management scheme is proposed to support seamless mobility between adjacent ASMD groups for wireless IPTV N-screen services. In simulation results, proposed ASMD channel management (ACM) scheme is compared with conventional WUSB channel management scheme in view points of throughput, average path interference and energy consumption according to various numbers of nodes and elapsed simulation times. Through simulation results, it is explained that proposed ASMD channel management (ACM) scheme should be adopted in the WUSB protocol to realize ASMD N-screen wireless services.