• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.11
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• pp.1121-1128
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• 2016

Our country of agriculture suffers problems such as aging, population decline, agricultural decline etc. To solve this problem, in the country, it is interest in Smart Farm System, a convenient and efficient system for the production through the convergence of ICT technology and agriculture. However, because of expensive construction costs and difficulty in securing human resources and training for Operating system, they are struggling to spread the actual farmers. Therefore, it is necessary to develop smart farm techniques suitable for such customized domestic environment. This study designed a system for collecting environment date in a greenhouse based on the low-cost embedded devices, and designed and implemented for the Web application that a user can easily use system. The implementation of the system lowers deployment costs and is expected to increase largely the spread of Smart Farm it can be easily accessed by using the smart phone.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.2
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• pp.75-85
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• 2014

Recently, mobile SNS traffic has increased tremendously due to the deployment of smart devices such as smart phones and smart tablets. In this paper, mobile integrated SNS gateway is proposed to cope with massive SNS traffic. Most of mobile SNS applications update the information with individual connection to the corresponding servers. The proposed gateway integrates these applications. It is for reducing SNS traffic caused by continuous data request and improving the mobile communication performance. The key elements of the mobile integrated SNS gateway are the synchronization, cache and integrated certification. The proposed protocol and gateway system have implemented on the testbed which deployed on the real network to evaluate the performance of the proposed gateway. Finally, we present the caching performance of gateway system implementation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12A
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• pp.1198-1206
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• 2010

Recently smart phone and tablet PC are regarded as the most valuable mobile devices, so the demand of customers for multimedia supporting has been greatly increased. The network operators are now considering the deployment of relay stations ensuring low installation costs for its service cell to improve the cell capacity. Enhancing the relay stations, however, increases intra-cell interference, which is affecting the quality of service and outage ratio. In this paper, we present MPFR(Multihop Partial Frequency reuse) as the new frequency reuse scheme to increase cell throughput while maintaining low outage ratio for the OFDMA cellular multihop networks. Dynamic power control is also introduced to improve cell capacity. Overall cell throughput and outage ratio are observed by the simulation, and comparison between MPFR and conventional multihop frequency reuse schemes is convincing the performance enhancement.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.8
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• pp.767-773
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• 2010

This paper describes development of a non-explosive separation device which can be equipped on small satellites. The spur geared micro DC motor, which has high reliability and advantage of price, is adopted as an actuator. The proposed separation device has resettability and it does not need extra jig to reload. In addition, the simple structure makes it easy to fabricate and assemble. To verify the performance of the proposed device, the response time tests, maximum preload tests and maximum shock level tests were performed. Also, through the vibration tests and thermal vacuum tests, feasibility of the proposed separation device was shown in launching and space environments. Therefore, we expect that the proposed separation device can replace the imported separation devices in near future.

• Journal of Internet Computing and Services
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• v.17 no.3
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• pp.11-18
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• 2016

Accessing unauthorized rogue APs in WiFi environments is a very dangerous behavior which may lead WiFi users to be exposed to the various cyber attacks such as sniffing, phishing, and pharming attacks. Therefore, prompt and precise detection of rogue APs and properly alarming to the corresponding users has become one of most essential requirements for the WiFi security. This paper proposes a new rogue AP detection method which is mainly using the installation information of authorized APs and the DHCP snooping information of the corresponding switches. The proposed method detects rogue APs promptly and precisely, and notify in realtime to the corresponding users. Since the proposed method is simple and does not require any special devices, it is very cost-effective comparing to the wireless intrusion prevention systems which are normally based on a number of detection sensors and servers. And it is highly precise and prompt in rogue AP detection and flexible in deployment comparing to the existing rogue AP detection methods based on the timing information, location information, and white list information.

• Journal of the Korea Society of Computer and Information
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• v.25 no.5
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• pp.127-135
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• 2020

In this paper, we propose an IoT-enabled solution for tour photography services with small-size investment and resources in the travel and tourism industries, being able to impact on economic, social, and cultural values. An IoT-enabled camera is developed based on an open hardware and software platform complying with oneM2M, which can make traditional embedded systems oneM2M-compliant devices due to a middleware solution called TAS (thing adaptation software). IoT cameras deployed around photo zones in a tour site could be remotely controlled via an IoT gateway with a Web-based application on a smartphone. Users would perform a pan and tilt camera control if they want and then take and download a perfect photo picture (even though they are away from the tour site). We expect that the proposed solution will promote the deployment IoT-enabled technologies in tour and travel industries which are important parts of the tertiary sector.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.1
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• pp.202-210
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• 2018

The modern battlefield is being developed as a network-centric warfare where priority is given to rapid status grasp and power deployment through scientification and modernization. Therefore, tactical data link has been continuously improving the network speed, and recently, security technology is required for wireless communication with the UAV and various devices for reconnaissance. In addition, the future information warfare will utilize advanced IT technology positively. Efforts are needed to integrate various systems and networks. However, these efforts are meaningful only when they can assume sufficient security in a newly changing information and communication environment. In this paper, we propose a new cryptographic synchronization for link encryption suitable for tactical data links. The proposed cryptographic synchronization is useful for T4 UAV link encryption, and it is also adaptable for lower BER, then we analyze the performances analysis of that.

• Journal of Information Technology Services
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• v.15 no.4
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• pp.97-109
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• 2016

The rapid deployment of millions of mobile sensors and smart devices has resulted in high demand for opportunistic encounter-based networking. For the cooperative video surveillance of dashboard cameras in nearby vehicles, a fast and energy-efficient asynchronous neighbor discovery protocol is indispensable because a dashboard camera is an energy-hungry device after the vehicle's engine has turned off. In the existing asynchronous neighbor discovery protocols, all nodes always try to discover all neighbors. However, a dashboard camera needs to discover nearby dashboard cameras when an event is detected. In this paper, we propose a fast and energy-efficient asynchronous neighbor discovery protocol, which enables nodes : 1) to have different roles in neighbor discovery, 2) to discover neighbors within a search range, and 3) to report promptly the exact discovery result. The proposed protocol has two modes: periodic wake-up mode and active discovery mode. A node begins with the periodic wake-up mode to be discovered by other nodes, switches to the active discovery mode on receiving a neighbor discovery request, and returns to the periodic wake-up mode when the active discovery mode finishes. In the periodic wake-up mode, a node wakes up at multiples of number ${\alpha}$, where ${\alpha}$ is determined by the node's remaining battery power. In the active discovery mode, a node wakes up for consecutive ${\gamma}$ slots. Then, the node operating in the active discovery mode can discover all neighbors waking up at multiples of ${\beta}$ for ${\beta}{\leq}{\gamma}$ within ${\gamma}$ time slots. Since the proposed protocol assigns one half of the duty cycle to each mode, it consumes equal to or less energy than the existing protocols. A performance comparison shows that the proposed protocol outperforms the existing protocols in terms of discovery latency and energy consumption, where the frequency of neighbor discovery requests by car accidents is not constantly high.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.5
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• pp.2103-2123
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• 2018

Ships built today are larger in scale and feature more complex structures. The ever-evolving systems used on board a ship require vast amounts of data processing. In the future, with the advent of smart ships, unmanned ships and other next-generation ships, the volumes of data to be processed will continue to increase. Yet, to date, ship data has been processed using wired networks. Placed at fixed locations, the nodes on wired networks often fail to process data from mobile devices. Despite many attempts made to use Wi-Fi on ships just as on land to create wireless networks, Wi-Fi has hardly been available due to the complex metal structures of ships. Therefore, Wi-Fi on ships has been patchy as the ship-wide total Wi-Fi coverage has not properly implemented. A new ship-wide wireless network environment is part of the technology conducive to the shipbuilding industry. The wireless network environment should not only serve the purpose of communication but also be able to manage and control multiple features in real-time: fault diagnostics, tracking, accident prevention and safety management. To better understand the characteristics of wireless frequencies for ships, this paper tests the widely used TETRA, UHF and Wi-Fi and sheds light on the features, advantages and disadvantages of each technology in ship settings. The proposed deployment of a Super Wi-Fi network leveraging the legacy UHF system of TMS generates a ship-wide wireless network environment. The experimental findings corroborate the feasibility of the proposed ship-wide Super Wi-Fi network environment.

• Convergence Security Journal
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• v.20 no.5
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• pp.11-17
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• 2020

With the increase in cases of using Bluetooth devices used in the electric vehicle charging systems, security issues are also raised. Although various technical efforts have beed made to enhance security of bluetooth technology, various attack methods exist. In this paper, we propose an intelligent Bluetooth intrusion detection system based on a well-known machine learning method, Hidden Markov Model, for the purpose of detecting intelligently representative Bluetooth attack methods. The proposed approach combines packet types of H4, which is bluetooth transport layer protocol, and the transport directions of the packet firstly to represent the behavior of current traffic, and uses the temporal deployment of these combined types as the final input features for detecting attacks in real time as well as accurate detection. We construct the experimental environment for the data acquisition and analysis the performance of the proposed system against obtained data set.