• The Journal of the Korea Contents Association
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• v.7 no.3
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• pp.17-24
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• 2007

SIP-based tightly coupled conference, which has a centrally located conference server for controlling and management, can be classified several models according to location of focus and mixer. These are centralized server model, endpoint server model, media server component model and distributed mixing model. However each model has its strength and weakness. In this paper, we propose and implement a SIP-based effective hybrid-type conference model which decreases amount of SIP signaling messages, lowers load of server media mixer, and can be easily expandable to large scale conference. In this model, when the number of participants exceeds a pre-defined limit, the conference server selects some participants which posses specific functions and let them share functions of notifications of conference state event package and media mixing. When each participant subscribes conference state event package to the server, it can indicates its possession of such functions by a specific header message. The server stores the indication to the conference information database, and later uses it to select participants for load sharing. The performance of our proposed model is evaluated by experiments.

• Korean Journal of Cognitive Science
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• v.20 no.1
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• pp.29-49
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• 2009

The purpose of the present research was to examine whether the parietal pathway and the temporal pathway were responsible for the phenomena of the inhibition of return and the facilitation of return respectively and at what stage of the information processing they occurred. The response time and the ERPs(event-related potentials) were examined in the two conditions(the valid condition and the invalid condition) while subjects were doing detection task, location discrimination task, color discrimination task and orientation discrimination task in separate sessions. No significant response time difference was found between the valid and the invalid conditions when subjects did the detection task as well as the location discrimination task. However, significant response time difference was found when they did the color discrimination as well as the orientation discrimination task. Futhermore, there was a significant difference of ERP difference between the two conditions in the Pz area when subjects were doing location discrimination task and significant difference was found in the T7 area when they were doing color discrimination task and marginal difference was found in T7/T8 area when they were doing orientation discrimination task just before they responded. These results imply the possibility that both the inhibition of return and the facilitation of return occur in the parietal and in the temporal pathway respectively in the late stage of information processing.

• Journal of Digital Convergence
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• v.11 no.12
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• pp.821-828
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• 2013

This paper proposed CHELS-App that Smart-phone APP optimized cultural heritage experiential learning is configured can learning and sightseeing at the same time with experience the cultural heritage and enjoying the mission through quests to take advantage of the Smart-phone. CHELS-App is provide a guide maps by using the location-based service and cultural commentary(commentary, photos, quizzes, games, cartoon) with capability of event push about the Jongmyo Shrine as world heritage, and configured with capability of experience diary create and foot stamp through these experiences.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.901-920
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• 2015

Wireless Sensor Networks (WSNs) are widely used in geographically isolated applications like military border area monitoring, battle field surveillance, forest fire detection systems, etc. Uninterrupted power supply is not possible in isolated locations and hence sensor nodes live on their own battery power. Localization of sensor nodes in isolated locations is important to identify the location of event for further actions. Existing localization algorithms consume more energy at sensor nodes for computation and communication thereby reduce the lifetime of entire WSNs. Existing approaches also suffer with less localization coverage and localization accuracy. The objective of the proposed work is to increase the lifetime of WSNs while increasing the localization coverage and localization accuracy. A novel intelligent unmanned aerial vehicle anchor node (IUAN) is proposed to reduce the communication cost at sensor nodes during localization. Further, the localization computation cost is reduced at each sensor node by the proposed intelligent arc selection (IAS) algorithm. IUANs construct the location-distance messages (LDMs) for sensor nodes deployed in isolated locations and reach the Control Station (CS). Further, the CS aggregates the LDMs from different IUANs and computes the position of sensor nodes using IAS algorithm. The life time of WSN is analyzed in this paper to prove the efficiency of the proposed localization approach. The proposed localization approach considerably extends the lifetime of WSNs, localization coverage and localization accuracy in isolated environments.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.12
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• pp.87-98
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• 1999

This study is concentrated on the development of real-time estimation model and vision control method as well as the experimental test. The proposed method permits a kind of adaptability not otherwise available in that the relationship between the camera-space location of manipulable visual cues and the vector of manipulator joint coordinates is estimate in real time. This is done based on a estimation model ta\hat generalizes known manipulator kinematics to accommodate unknown relative camera position and orientation as well as uncertainty of manipulator. This vision control method is roboust and reliable, which overcomes the difficulties of the conventional research such as precise calibration of the vision sensor, exact kinematic modeling of the manipulator, and correct knowledge of position and orientation of CCD camera with respect to the manipulator base. Finally, evidence of the ability of real-time vision control method for manipulator's position control is provided by performing the thin-rod placement in space with 2 cues test model which is completed without a prior knowledge of camera or manipulator positions. This feature opens the door to a range of applications of manipulation, including a mobile manipulator with stationary cameras tracking and providing information for control of the manipulator event.

• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.58-62
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• 2012

Emergency alerting broadcasting of T-DMB is being serviced to deliver the event of a disaster to the people quickly and effectively through a T-DMB network. DGPS has been developed in order to improve the accuracy of the GPS receiving data and transmitting of DGPS information through the T-DMB network is being studied for a wide range of usage. Because DGPS information and AEAS message are sent through the same T-DMB network, if DGPS information is applied to AEAS message disaster area can be specified more precisely and the exact location of the disaster can be measured in the terminal. In this paper, a implementation method of T-DMB emergency alerting broadcasting system based on a DGPS including a new structure of AEAS message was proposed to identify the location of disaster accurately.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.122-128
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• 2022

Minimization of human casualties in disaster situations is of paramount importance. In particular, if a marine disaster occurs, it can be directly connected to human casualties, so prompt action is needed. In the event of a marine disaster, the route and location of movement should be identified and life tubes should be used to float on the water. This paper designs and proposes an emergency IoT notification system that can quickly rescue drowning people. The maritime emergency IoT notification system consists of four main types. First, an emergency IoT device that detects the expansion of the life tube and delivers location and situation information to the emergency IoT notification server. Second, an emergency IoT web server that manages emergency information and provides notification. Third, a database server that stores and manages emergency IoT notification information. And finally, an emergency notification app that can receive and respond to emergency notification information. The emergency IoT device consists of a TPMS(Tube Pressure Monitoring System) device that checks the pressure value of the TPMS in real time and sends it to the IoT device, and an IoT device that sends the rescuer's voice information and emergency information to the emergency IoT server. Emergency information is delivered using the MQTT(Message Queuing Telemetry Transport) protocol, and voice information is delivered to the IoT server as HTTP FormData.

• Fire Science and Engineering
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• v.17 no.1
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• pp.8-20
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• 2003

Natural gas has been supplied through underground pipelines and valve stations as a new city gas in Seoul. In contrast to its handiness the natural gas has very substantial hazards due to fires and explosions occurring from careless treatments or malfunctions of the transporting system. The main objectives of this study are to identify major hazards and to perform risk assessments after assessing reliabilities of the composing units in dealing with typical pipeline networks. there-fore two method, fault tree analysis ;1nd event tree analysis, are used here. Random valve stations are selected and considered its situation in location. The value of small leakage, large rupture, and no supply of liquefied natural gas is estimated as that of top event. By this calculation the values of small leakage are 3.29 in I)C valve station, 1.41 in DS valve station, those of large rup-lure are $1.90Times10_{-2}$ in DC valve station, $2.32$\times$10^{-2}$ in DS valve station, and those of no supply of LNG to civil gas company are $2.33$\times$10 ^{-2}$ , $2.89$\times$10^{-2}$ in each valve station. And through minimal cut set we can find the parts that is important and should be more important in overall system. In DC valve station one line must be added between basic event 26,27 because the potential hazard of these parts is the highest value. If it is added the failure rate of no supply of LNG is reduced to one fourth. In DS valve station the failure rate of basic event 4 is 92eye of no supply of LNG. Therefore if the portion of this part is reduced (one line added) the total failure rate can be decreased to one tenth. This analytical study on the risk assessment is very useful to prepare emergency actions or procedures in case of gas accidents around underground pipeline networks and to establish a resolute gas safety management system for loss prevention in Seoul metropolitan area.

• Journal of Korea Water Resources Association
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• v.51 no.7
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• pp.555-564
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• 2018

The detention reservoir is a hydraulic structure that constructs a levee on the inland of river and sets up side weir in a section of the levee, and this facility stores a part of the flood volume in case of a flood event over a certain scale. In order to optimize the operation of detention reservoir, it is necessary to review the linkage with existing facilities in the river. In this study, the effect of water level reduction and the flow distribution was analyzed according to the location of the side weir in the detention reservoir considering the run-of-the-river gate. Two radial gates were installed in the experimental channel, and the water level in channel and the overflow of weir were measured by moving the location of the side weir upstream from the gate. As a results of experiment, it was confirmed that the water level reduction is more remarkable as the location of the side weir was closer to the gate, and the effect of flow distribution is not greatly changed. When two or more side weirs were operated, it is confirmed that the sufficient storage space was secured and the water level reduction effect with the location of the side weir is not large. In addition, the water level reduction rate according to the location of the side weir was estimated by empirical formula and it is provided as basic data that can be used in the planning of the detention reservoir.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.2
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• pp.125-137
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• 2007

This paper proposes a new scheme to provide the location privacy of sources in Wireless Sensor Networks (WSNs). Because the geographical location of a source sensor reveals contextual information on an 'event' in WSN, anonymizing the source location is an important issue. Despite abundant research efforts, however, about data confidentiality and authentication in WSN, privacy issues have not been researched well so far. Moreover, many schemes providing the anonymity of communication parties in Internet and Ad-hoc networks are not appropriate for WSN environments where sensors are very resource limited and messages are forwarded in a hop-by-hop manner through wireless channel. In this paper, we first categorize the type of eavesdroppers for WSN as Global Eavesdropper and Compromising Eavesdropper. Then we propose a novel scheme which provides the anonymity of a source according to the types of eavesdroppers. Furthermore, we analyze the degree of anonymity of WSN using the entropy-based modeling method. As a result, we show that the proposed scheme improves the degree of anonymity compared to a method without any provision of anonymity and also show that the transmission range plays a key role to hide the location of source sensors.