• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.6
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• pp.478-488
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• 2023

This paper investigates the naval application of laser communication as a potential replacement for traditional acoustic wave communication in underwater environments. We developed a laser transceiver using Arduino and MATLAB, conducting a water tank experiment to validate communication feasibility across diverse underwater conditions. In the first experiment, when transmitting data through a laser, the desired message was converted into data and transmitted, received, and confirmed to be converted into the correct message. In the second experiment, the operation of communication in underwater situations was confirmed, and in the third experiment, the intensity of light was measured using the CDS illuminance sensor module and the limits of laser communication were measured and confirmed in various underwater situations. Additionally, MATLAB code was employed to gather data on salinity, water temperature, and water depth for calculating turbidity. Optimal wavelength values (532nm, 633nm, 785nm, 1064nm) corresponding to calculated turbidity levels (5, 20, 55, 180) were determined and presented. The study then focuses on analyzing potential applications in naval tactical communication, remote sensing, and underwater drone control. Finally, we propose measures for overcoming current technological limitations and enhancing performance.

• The Transactions of the Korea Information Processing Society
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• v.4 no.4
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• pp.1089-1099
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• 1997

The Q.2931 protocol describes the point-to-point basic call/connection controal at user-network interface(UNI) and is the core part of the Signalling Capability Set 2 step 1 (CS 2.1) of B-ISDN in ITU-T.The adtivities on CS 2.1 is also under study in korea and categorized as the first stage.The Q.2931 protocol should be applied to various devices with cinsistency especially among network divices.But , It is hard to inmplement this protocol into a de-vice with cinsistency because this protocol has so many optious.Especially, the divice that charges for network foles must takes into account of various considerations.In this paper, we focused our study on the optional in-formantion elments of the Q.2931, and would like ot redefine the chracteristics of optional information elements for the point of the national boundary and proposed some common actions to the devies with network role.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1059-1068
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• 2011

This study is aimed to systematically grasp the visual and informative needs of sign system and secure the formativeness sample for standardization model. This study, therefore, will help building the requirements to create design value and secure objectiveness for realization of practical use of the communication design plan, and means transference of the external and internal information system of railroad vehicles for practical use into the standardization model. The pictorial sign based information delivery is a communication process and way gained through vision and perception, so that grasping the formative structure connoted in message is not less than understanding the characteristics of the essence. In this study, I defined the symbolic expressions inherent in TTX sign system to be perceptional action and value norms as general signatures and signifiers.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.9
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• pp.1730-1740
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• 2016

This paper introduces a guest identity provider system for eduroam which is a global Wi-Fi service targeting users enrolled in higher education and research institutions. Developed eduroam AND (AutheNtication Delegation) system enables users to create their eduroam user accounts and to access eduroam regardless of their locations. Users with no organizational eduroam account therefore can freely access eduroam using the system. A federated authentication model is implemented in the system, and thus the system has merits of having high accessibility, indirectly verifying users and organizations possible, saving management overhead. Status monitoring is essential because authentication request and response messages are routed by eduroam network. eduroam AND performs active monitoring to check service availability and visualizes the results, which increases operational and management efficiency. We leveraged open-source libraries to implement eduroam AND and run the system on KREONET (Korea REsearch Open NETwork). Lastly, we present implementation details and qualitively evaluate the system.

• Journal of Korean Society of Transportation
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• v.26 no.1
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• pp.79-88
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• 2008

VMS based dispersion of traffic flows enables to decrease delay and congestion. Such being the case, there has been growing interests in VMS operation strategy. The strategy is based on driver's behavior or diversion rate. However, it was not easy to obtain each in practice. The diversion rate, thus far, was investigated by stated preference analysis or simulators. As an alternative, in this paper, a new method to obtain diversion flow rate was suggested using the toll collection system and freeway traffic management system data. A large gap of diversion rate between stated preference analysis and field survey was observed. Out of surveyed 8 tollgate data, the diversion rate was about 7% and was quite lower compared with that of 21%${\sim}$87% from stated preference analysis or simulators. With this at hand, a more careful information provision strategy should be devised and employed to correctly account this kind of differences.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.6
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• pp.86-92
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• 2010

This paper proposes a new steganography scheme based on frequency domain using various image frames and collages that can protect the copyright of digital contents for users and securely perform to exchange the security information in the digital communication environments. The main idea of our proposed scheme is that the security informations related its copyright embed into the frequency domain of the image frame and collages when a user decorates the original image by using various image frames and collages. The strengths of our proposed scheme are as follows: (1) It allows to freely control the quantity of embedded information by changing the number of image frames and collages. (2) It is secure to variety image distortion attacks. (3) It maintains high PSNR(Peak Signal to Noise Ratio). As a result, the proposed steganography scheme can be used practically diverse multimedia security fields such as digital copyright protect, secure message communication and digital watermarking.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.1 no.1
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• pp.40-50
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• 2002

A traditional agent was difficult to upgrade and to add MIB implementation code to it because most SNMP agent designs had MIB that was not a self-contained module. To solve this problem, we design the SNMP agent bundle composed of remotely uploadable SNMP agent core bundle and MIB Bundle Also, downloadable server bundle and user administration bundle is added to SNMP agent bundle to download MIB bundle from bundle server. By designing MB-MIB, we enable the network manager to monitor status of MIB bundle on managed devices. The network manager is allowed to install and upgrade the SNMP module or MIB remotely on line. This is the major benefit of designing the SNMP agent bundle based on OSGi. Finally, we expect the network manager to reduce time and expenses in managing enormous networks by using the SNMP agent bundle.

• The KIPS Transactions:PartC
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• v.17C no.3
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• pp.281-290
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• 2010

In geographic forwarding algorithms, traditional route maintenance requires mobile nodes periodically exchange beacon messages with their neighbors. In beacon message based forwarding scheme, a longer interval reduces the number of beacons needed, but may result in significant location errors. Conversely, a shorter interval guarantees more accurate location information, but induces control overheads.Therefore, the fixed or dynamic interval scheme based forwarding schemes cannot adapt well to different mobility environments. Also, existing schemes result in the uncertainty of neighbor node's position in the forwarding table of mobile node. Therefore, this paper presents a self-adaptive location checking mechanism based proactive geo-routing algorithm for beacon-based geographic routing. Simulation results show that the proposed routing algorithm not only significantly increases the relay transmission rate but also guarantees the high end-to-end packet delivery in low and high mobility environments.

• Journal of Advanced Navigation Technology
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• v.20 no.5
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• pp.433-439
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• 2016

Several low-cost global navigation satellite system (GNSS) receivers do not support general range-domain correction, and DGNSS-CP (differential GNSS) method had been suggested to solve this problem. It improves its position accuracy by projecting range-domain corrections to the position-domain and then differentiating the stand-alone position by the projected correction. To project the range-domain correction, line-of-sight vectors from the receiver to each satellite should be calculated. The line-of-sight vectors can be obtained from GNSS broadcast ephemeris data or satellite direction information, and this paper shows positioning performance for the two methods. Stand-alone positioning result provided from Septentrio PolaRx4 Pro receiver was used to show the difference. The satellite direction information can reduce the computing load for the DGNSS-CP by 1/15, even though its root mean square(RMS) of position error is bigger than that of ephemeris data by 0.1m.

• Journal of KIISE:Information Networking
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• v.35 no.2
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• pp.120-129
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• 2008

The purpose of sensor network is gathering the information from sensor nodes. If there are selfish node that deliberately avoid packet forwarding to save their own energy, the sensor network has trouble to collect information smoothly. To solve this problem we suggest a mechanism which uses credit payment schema according to the amount of forwarding packets. Sensor nodes use credits to send their own message and they forward packets of other sensor nodes to get credits. To offer authenticity we combined the roles of sink node and server, also we used piggybacking not to send additional report message. The packet trace route is almost fixed because sensor node doesn't have mobility. In this case, it happens that some sensor nodes which don't receive forwarding packets therefore they can't get credit. So, we suggested the way to give more credits to these sensor nodes. Finally, we simulated the suggested mechanism to evaluate performance with ns2(network simulator). As a result, packet transmission rate was kept on a high rate and the number of arrival packets to sink node was increased. Also, we could verify that more sensor nodes live longer due to deceasing the energy consumption of sensor nodes.