• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.5
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• pp.1099-1116
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• 2019

Industrial control systems(ICS) are widely used in various industrial area and critical infrastructure. To mitigate security threats on ICS, the security assurance test for industrial control devices has been introduced and operating. The test includes testing of the security function of the device itself and testing of communication robustness. In this paper, we describe the security requirements of EDSA, Achilles, and Korea's TTA standard(security requirements for ICS). And also, we analyzed the characteristics of communication robustness test(CRT) of each certification. CRT verifies the device's operation of essential function while transmitting fuzzing and stress packets. Existing test methods are mostly focused on the embedded devices and are difficult to apply to various devices. We propose a method to test communication robustness which reflect the characteristics of control H/W, control S/W, field devices and network devices in ICS. In the future, we will apply the proposed communication robustness test to actual products and present solutions for arising issues.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.5
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• pp.991-998
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• 2012

This study considered NCW in the general as a key component of Future War and analyzed the international technical trend of tactical data link as the key of technical elements. The technique applied to Future War results from development of electronic communication and IT technique. However, NCW which plays a significant role in the Future War is not possible due to a development of simple technique but requires the amalgamative approach of various techniques essentially. That is, it should be understood and approached the management scenario and various techniques comprehensively. NCW is one of the areas which future electronic communication and IT can concentrate, so the government has been working for the developmental introduction of NCW strategically until 2020. Already, the level of localization of components related to electronics in military supplies exceeds 85%, but under the amalgamative research of technology in the high level like this, it would be possible to create new opportunities. Thus, the electronic communication and IT technology should seek effective applications of NCW by comprehending each area complexly.

• Journal of Satellite, Information and Communications
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• v.8 no.4
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• pp.135-141
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• 2013

Subway in Korea, most of a metropolitan public transport use only worth ten million people a day floating population of wireless communication can be considered HOT SOPT. These three operators' 2G/3G/4G / Wi-Fi / T-DMB frequency and the number of services to co-exist, and the subway train passengers and subway party for operation and management of the communication network is also the co-subway passenger safety and for this service for the effects of mutual interference of whether the verification was necessary. This research and testing different frequency / communication interference between services and testing to determine whether, through the subway authorities and mobile operators in each frequency-specific interaction check and there is no interference to the safety and quality of subway passengers communication services that can be verified as the data was found. The verification methods in the metro area, not just from one region to determine whether the interference with a common verification methods can be applied.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.9
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• pp.1939-1946
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• 2012

USNs (Ubiquitous Sensor Networks) such as IEEE 802.15.4 ZigBee network share ISM (Industrial, Scientific, and Medical) frequency band with WiFi networks. Once both networks operate in a region, packet collision may happen because of frequency overlapping. To assure this possibility, we conducted experiments where WiFi and ZigBee communication networks had been installed in an area. As a result of the test, successful data transmission rate were reduced due to the frequency overlapping between a WiFi communication channel and a ZigBee communication band. To cope with this problem, we propose a collision avoidance algorithm. In the proposed algorithm, if frequency collision is sensed, new communication channel with different frequency band is allocated to each node. Performance of the proposed frequency collision avoidance algorithm was tested and the results were described.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.620-627
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• 2004

As h-bridge multilevel inverter is connected with series of single phase power cell, so it obtain high voltage using low voltage power semi-conductor and output voltage similar to sine wave. In this topology, the number of power cell increases in proportion to the output voltage level. Therefore, there are drawbacks that are responsibility against operating ability of main controller and signal wire increase. However, we can overcome this problems by the substitution of serial communication for the PWM signal in power cell control. Additionally, it has merits of reliability and maintenance. This paper deals with the synchronization and phase-shift method of power cell PWM using CAN(Controller Area Network) communication interrupt in H-bridge multilevel inverter. The advantages of proposed method are signal-line simplification using serial communication between main controller and cell controller, burden reduction in main controller, modularization of power cell, easy protection of each power cell, expandability improvement and reliability increase of control signal and power cell. This paper establishes propriety and reliability of proposed method through experiment of 13-level H-bridge multilevel inverter.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.215-221
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• 2011

Communication infrastructure of wireless sensor networks significantly tends to depend on application requirements. Gossip communication is becoming one of the promising solutions for addressing its scalability problems in providing information propagation functionality based on the P (publish)/S (subscribe) paradigm. In particular, despite the importance of both guaranteeing message delivery order required and supporting overlapping groups in sensor networks, there exist little research works on development of gossip-style dissemination protocols to satisfy all these requirements. In this paper, we present the latest causal information transmission protocol between publishers and subscribers for overlapping groups. In this protocol, sensor leaders as publishers might guarantee consistently causally ordered message delivery among themselves by aggregating causality information. On the other hand, only the latest causal information piggybacked on each multicast message is transmitted from publishers to subscribers through gossip-style dissemination. Its scalability feature might be highly suitable for the area of the applications requiring only the minimum meaningful information.

• Tunnel and Underground Space
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• v.29 no.6
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• pp.367-378
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• 2019

As the development of IT technology, the way to manage the underground construction site in real time using wireless network communication is being considered. Underground space is limited area compared to the ground site due to the enclosed communication environment and spatial characteristics. BMN (Bluetooth Mesh Networking) technology is a recently introduced wireless communication technology that bluetooth device acts as a repeater to form a networking mesh and monitor individual devices. This article examines the areas to be considered for analyzing the applicability of BMN technology to underground spaces, and the cases studies of wireless communication monitoring systems currently being developed. And the BMN technology which is being developed for the underground application is also introduced.

• International Journal of Highway Engineering
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• v.11 no.3
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• pp.129-139
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• 2009

The transportation network is a critical infrastructure in the event of natural and human caused disasters such as rainfall, snowfall, and terror and so on. Particularly, the transportation network in an urban area where a large number of population live is subject to be negatively affected from such events. Therefore, efficient traffic operation plans are required to assist rapid evacuation and effective detour of vehicles on the network as soon as possible. Recently, ubiquitous communication and sensor network technology is very useful to improve data collection and connection related emergency information. In this study, we develop a specific algorithm to provide evacuation route and detour information only for vehicles under emergency situations. Our algorithm is based on shortest path search technique and dynamic traffic assignment. We perform the case study to evaluate model performance applying hypothetical scenarios involved terror. Results show that the model successfully describe effective path for each vehicle under emergency situation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.669-672
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• 2015

Recent Internet of Things (IoT, Internet of Things) that can be applied to various fields as the development of technology has been developed a lot of service and has been developed with the service also for crop management. To manage the essential elements of soil moisture in the crop growth but existing a direct person measuring the fluid point to carry the measuring instrument, if you take advantage of the WPAN (Wireless Personal Area Network) in this paper to manage sensor data, a fixed 3 points (30, 60, 90 cm) and can be managed can be scientifically analyzed the state of growth of the crop. Open field environment is utilized as it is less disturbance of the interference and the frequency of the radio frequency signal of the structure provides a relatively comfortable environment. Therefore, WPAN building and data transmission scheme of the minimum cost is to be developed. In addition, the operation to enter low power mode, the algorithm is necessary because a lot of restrictions on the power supply applied to the sensor nodes and the gateway is constructed in the open field. In the experiment, verifying the effectiveness by using a network configuration of each of the sensor nodes and the gateway, and provides a method for time synchronization of the operation and a low power mode. The study protocol for the RF communication with the LoRa and to enhance communication efficiency is needed in the future.

• KIPS Transactions on Computer and Communication Systems
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• v.1 no.1
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• pp.35-46
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• 2012

The development of wireless communication systems has resulted in the availability of several access technologies at any geographic area, such as 3G networks, wireless local area networks (WLANs) and wireless broadband networks. The development of these technologies is provided for users who have experienced mobile network environments which are slow or fast-movement environment and change distance between the AP(Access Point). This paper describes network performance issues in various environmental changes. Also, Fuzzy logic is applied to evaluate the performance in vehicle networks around users' environmental factors to focusing on the minimizing of transfer time and costs. First, WLAN and 3G networks fixed distance between AP, Second, WLAN and 3G networks random distance between APs, finally above two environmental with vehicle Ad hoc networks is analyzed. These V2I and V2V environmental condition are assumed. Results which based on Fuzzy logic suggest an optimal performance in vehicle network environments according to vehicle speed and distance between APs. Proposed algorithm shows 21% and 13% improvement of networks performance in V2I and V2V environment.