• Journal of Digital Convergence
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• v.15 no.7
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• pp.201-211
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• 2017

Wireless network using dynamic IP and mobile IP technology provides the user with convenience of access and movement. However, this causes the attacker who disguises normal user(pretending to be a regular user) to have more opportunity in regard to access and acquisition of information. This paper help the network administrator and the service provider quickly to recognize the attacker's intention to access network and service. Therefore network administrator and service provider can specify and respond the location of the attacker appropriately. To achieve above, we define an entity (W_L_M) that manages user information of WiFi and LTE network, and propose messages and procedures for attacker's location identification and alarm. The performance evaluation of this paper is based on qualitative analysis. By using the proposed method, some cost (message creation, processing and transmission) occurred but it was analyzed to be less than the total network operation cost. The proposal of this paper is a management method that utilizes existing network information and structure. This method can be used as a reference material to enhance security.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.9
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• pp.285-292
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• 2016

By adding short-range wireless communication function such as Bluetooth and Wi-Fi to the last vehicle in conjunction with a smart phone, a modern automobile is becoming entertainment screen to determine a variety of information such as car location information, diagnosis information, etc. through the ECU vehicle electronic control unit. In this study, by utilizing short-range communications capability of the on-board diagnostic devices and smart phones in association with the on-board diagnostics, compatibility tests among a number of smart phone models, Bluetooth and NFC(Near Field Communication) were carried out and those results were analyzed. Furthermore, composition of on-board diagnostic device having Bluetooth and NFC interface function and the fault diagnosis function were implemented, and fault diagnosis debugging program was developed. In addition, fault diagnosis data of the vehicle via the OBD-II interface was extracted. Finally, the on-board diagnostics CAN Protocol implementation has been proposed, and the results of work was analyzed.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.6
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• pp.197-208
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• 2023

In the coming future, anyone using the Internet will have more than one NFT. Unlike FT, NFT can specify the owner, and tracking management is easier than FT. Even in the 2022 survey, WPA2 is the most widely used wireless protocol worldwide to date. As it is a protocol that came out in 2006, it is a protocol with various vulnerabilities at this time. In order to use WPA2-EAP or WPA3 (2018), which were released to compensate for the vulnerabilities of WPA2, additional equipment upgrades are required for STA (station) and AP (access point, router), which are connected devices. The use of expensive router equipment solves the security part, but it is economically inefficient to be introduced in Small Office Home Office (SOHO). This paper uses NFT as a means of authentication and uses the existing WPA2 as it is without equipment upgrade, defend crack tools of WPA2 that have been widely used so far and compared to the existing WPA2, it was shown that it was not difficult to actually use them in SOHO.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.239-241
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• 2011

Recently, studies on the indoor positioning system in application of wireless AP have been actively going on. The indoor wireless positioning system can be classified into several types according to the positioning techniques. Among them, the fingerprint technique is a technique that establishes the radio map by collecting MAC information of AP and RSSI (Received Signal Strength Indication) before executing positioning and then determines the position in comparison with the information of AP collected during the course of positioning. In the traditional fingerprint techniques, they control and manage by installing APs that are utilized for positioning. However, in case of specific indoors, the management can be done by installing a small number of APs but, in case of wide outdoors, it's practically impossible to install and manage equipments for positioning. In order to solve such problem, there is an improved fingerprint technique that utilizes the APs that are already scattered around. This technique will allow positioning without additional cost, but even the improved fingerprint positioning technique may incur dropped accuracy as well due to wide fluctuation of the AP information. In this paper, the traditional fingerprint technique and the improved fingerprint technique are explained in comparison, and we will compares difference in performance with the proposed WPS_WS (Wi-Fi Positioning System_Weak Signal) technique.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.5
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• pp.937-941
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• 2016

This paper proposed an efficient multiple TCP mechanism using Android smartphones for remote control video Wi-Fi stream transmission via network communications in real time. The wireless video stream transmission mechanism can be applied in various area such as real time server stream transmissions, movable drones, disaster robotics and real time security monitoring systems. Moreover, we urgently need to transmit data in timely fashion such as medical emergency, security surveillance and disaster prevention. Our parallel TCP transmission system can play an important role in several area such as real time server stream transmissions, movable drones, disaster robotics and real time security monitoring systems as mentioned in the previous sentence. Therefore, we designed and implemented a parallel TCP transmission (parallel stream) for an efficient real time video streaming services. In conclusion, we evaluated proposed mechanism using parallel TCP transmission under various environments with performance analysis.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.53-60
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• 2017

This paper is to design and implement the drone that supports a wideband multimedia communication and a long-range to save people in maritime. The drone is an Unnamed Aerial Vehicle (UAV) that is controlled by a radio wave not by people boarding the machine. We use the drone to respond quickly to the boating accident. To develop a smart drone for the high speed seamless video streaming in a long-range maritime, a necessary techniques are hardware design techniques that design structure of a drone, controlling techniques that operate a drone and communication techniques that control a drone in a long distance. In this paper, the limitations and techniques to design and implement the structure of drone supporting wideband multimedia communication for long-range maritime are explained. By expanding this communication drone network, it is aimed at improving utility of a drone.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.953-958
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• 2015

Raspberry Pi is a credit card-sized computer with support for a large number of input and output peripherals. This makes it the perfect platform for interaction with many different devices and for usage in a wide range of applications. When combined with Wi-Fi, it can communicate remotely, therefore increasing its suitability for the construction of wireless sensor nodes. In addition, data processing and decision-making can be based on artificial intelligence, what is performed in developed testbed on the example of monitoring and determining the confidence of fire. In this paper, we demonstrated the usage of Raspberry Pi as a sensor web node for fire-safety monitoring in a building. When the UV-flame sensors detect a flame as thin as that of a candle, the Raspberry Pi sends a push-message to notify the assigned smartphone of the on-site situation through the GCM server. A mobile app was developed to provide a real-time video streaming service in order to determine a false alarm. If an emergency occurs, one can immediately call for help.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.12
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• pp.1102-1112
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• 2012

We propose a cell selection and resource allocation scheme that assigns users to nearby accessible cells in heterogeneous wireless networks consisting of macrocell, femtocells, and Wi-Fi access points, under overload situation. Given the current power level of all accessible cells nearby users, the proposed scheme finds all possible cell assignment mappings of which user should connect to which cell to maximize the number of users that the network can accommodate at the same time. We formulate the cell selection problem with heterogeneous cells into an optimization problem of binary integer programming, and compute the optimal solution. We evaluate the proposed algorithm in terms of network access failure compared to a local ad-hoc based cell selection scheme used in practical systems using network level simulations. We demonstrate that our cell selection algorithm dramatically reduces network access failure in overload situation by fully leveraging network resources evenly across heterogeneous networks. We also validate the practical feasibility in terms of computational complexity of our binary integer program by measuring the computation time with respect to the number of users.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.1005-1018
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• 2017

This paper proposes an App Visualization (AppV) based on IoT Self-diagnosis Micro Control Unit (ISMCU) for accident prevention. It collects a current status of a vehicle through a sensor, visualizes it on a smart phone and prevents vehicles from accident. The AppV consists of 5 components. First, a Sensor Layer (SL) judges noxious gas from a current vehicle and a driver's driving habit by collecting data from various sensors such as an Accelerator Position Sensor, an O2 sensor, an Oil Pressure Sensor, etc. and computing the concentration of the CO collected by a semiconductor gas sensor. Second, a Wireless Sensor Communication Layer (WSCL) supports Zigbee, Wi-Fi, and Bluetooth protocol so that it may transfer the sensor data collected in the SL to ISMCU and the data in the ISMCU to a Mobile. Third, an ISMCU integrates the transferred sensor information and transfers the integrated result to a Mobile. Fourth, a Mobile App Block Programming Tool (MABPT) is an independent App generation tool that changes to visual data just the vehicle information which drivers want from a smart phone. Fifth, an Embedded Module (EM) records the data collected through a Smart Phone real time in a Cloud Server. Therefore, because the AppV checks a vehicle' fault and bad driving habits that are not known from sensors and performs self-diagnosis through a mobile, it can reduce time and cost spending on accidents caused by a vehicle's fault and noxious gas emitted to the outside.

• Journal of KIISE:Information Networking
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• v.32 no.6
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• pp.723-731
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• 2005

Wide spread deployment of infrastructure WLANs has made Wi Fi an integral part of today's Internet access technology. Despite its crucial role in affecting end to end performance, past research has focused on MAC protocol enhancement, analysis and simulation based performance evaluation without sufficient consideration for modeling inaccuracies stemming from inter layer dependencies, including physical layer diversity, that significantly impact performance. We take a fresh look at IEEE 802.11 WLANs, and using experiment, simulation, and analysis demonstrate its surprisingly agile performance traits. Contention based MAC throughput degrades gracefully under congested conditions, enabled by physical layer channel diversity that reduces the effective level of MAC contention. In contrast, fairness and jitter significantly degrade at a critical offered load. This duality obviates the need for link layer flow control for throughput improvement but necessitates traffic control for fairness and QoS. We use experimentation and simulation in a complementary fashion, pointing out performance characteristics where they agree and differ.