• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.4
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• pp.829-836
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• 2013

Wireless mesh networks(WMNs) are wireless backbone networks technology consisting of a multi-hop routers. Location management is essential to provide a service to the terminal in WMNs. IEEE 802.11s standards have two basic location management scheme for location management - the proxy registration procedure and the associated station discovery protocol. These basic schemes, however, suffer from serious drawbacks including redundancy control message, ineffective location information maintenance, additional delay time. This paper propose an on-demand station location management scheme using 6-address structure of IEEE 802.11s. Through analysis and experimental evaluation on simulation, we show that proposal scheme reduce control message and forwarding delay time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2292-2298
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• 2010

A mashup is a web page or application that uses and combines information, contents or Open APIs available on the web to create a new service. The mashup developed by the need not combination of simple information can contribute to new added-values with practicality and convenience. Thus, in this paper, we want to develop a RIA-based dynamic mashup service for the users considering weather forecast and marine information importantly. We design and implement the system that it can register a number of information about a domain dynamically through registration process based on the map and present a mark of domain location on the map and the information including internal environment, external environment and weather of related to the domain within a webpage. Implemented service need not require a tedious process visiting other web sites every time to confirm the relevant information because we can see simultaneously related information with a map within a page.

• Journal of the Korea Society of Computer and Information
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• v.25 no.1
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• pp.101-107
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• 2020

We propose a realistic seeing through visualization methods in mixed reality environment. When a user wants to see specific location beyond a wall in indoor environment. The proposed system recognizes and registers the selected area using environment modelling and feature-based tracking. Then the selected area is diminished and the specific location is visualized in real-time. With the proposed seeing through methods, a user can understand spatial relationship of the building and can easily find the target location. We conducted a user study comparing the seeing through method to conventional indoor navigation service in order to investigate the potential of the proposed seeing through method. The proposed seeing through method was evaluated in navigation time in comparison with conventional approach. The proposed method enable users to navigate target locations 30% faster than the conventional approach.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.7
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• pp.1344-1356
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• 2009

The DDS (Data Distribution Service) is a data-centric communication technology that provides an efficient communication service that supports a dynamic plug & play through an automatic setting of participants' location information for each data (Topic) by using DDS discovery technique. This paper proposes the hierarchical-structured DDS discovery technique (SPDP-TBF) suitable for the large-scale distributed systems by comparing and analyzing the existing DDS discovery techniques in terms of performance and problem areas. The proposed SPDP-TBF performs the periodic discovery of the involved participants only by having separate hierarchical managers which take charge of the registration and search (of participants) so that a participant sends its information to the related participants only, and it enhances the effectiveness of the message transfer. Moreover, the proposed SPDP-TBF provides the improved scalability by performing the hierarchical discovery through hierarchical manager nodes so that it can be applied to the large-scale distributed system.

• Journal of Internet Computing and Services
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• v.12 no.1
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• pp.11-25
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• 2011

In ubiquitous computing environment, OSGi has applied to many areas such as digital mobile phones, vehicles, telematics, embedded appliances, residential gateways, industrial computers, desktop PCs, and high-end servers including mainframes. Therefore, interoperability is required for remote OSGi services which are built on various devices. In this paper, we proposed a method which was able to interoperate remote OSGi services using RMI paradigm. RMI is a representative middleware technology in distributed computing environment. The suggested method is based on the standard OSGi technology. It is possible to provide remote OSGi service registration, finding, and binding methods which were suitable for the OSGi service-oriented architecture. We also provided reliability of the dynamic remote OSGi services by maintaining consistent properties of them, and we could provide location transparency of the remote OSGi services by generating proxy bundles and proxy services dynamically.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.942-955
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• 2000

This paper proposes enhanced designs of global service logic and information flow for the mass-call based IN service, which increase call completion rates and optimize the resource in joint wired and wireless networks. In order to hanve this logic implemented, we design a Dynamic Queue Manager(DQM) applied to the call queuing service feature in the Service Control Point(SCP). In order to apply this logic to wireless service subscribers as well as wired service subscribers, the service registration flags between the Home Location Register(HLR) and the SCP are managed to notify the DQM of the corresponding service subscribers’ mobility. Hence, we present a dynamic queue management mechanism, which dynamically manages the service group and the queue size based on M/M/c/K queueing model as the wireless subscribers roam the service groups due to their mobility characteristics. In order to determine the queue size allocated by the DQM, we simulator and analyze the relationship between the number of the subscriber’s terminals and the drop rate by considering the service increment rate. The appropriate waiting time in the queue as required is simulated according to the above relationship. Moreover, we design and implement the DQM that includes internal service logic interacting with SIBs(Service Independent building Blocks) and its data structure.

• Environmental Analysis Health and Toxicology
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• v.30 no.sup
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• pp.5.1-5.5
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• 2015

Objectives To protect public health from risk, the Minister of Environment in Korea legislated an act concerning the registration and evaluation of chemical substances. In this study, we estimated the value of a statistical life (VSL) of carcinogenic chemicals to evaluate the socioeconomic analysis in Korea. Methods The estimation of the health benefit can be calculated through an individual's VSL and willingness to pay (WTP). To estimate the VSL and WTP, we used a contingent valuation method through a web-based survey. Results The survey is conducted with 1434 people living in Seoul and six large cities. An analysis of the survey is essential to review the distribution of the characteristics of the target population. The statistically significant variables affecting the WTP are location, age, household income, quality of life. Through the review of data, we secured statistical validity. The WTP was estimated as 41205 Korean won (KRW)/person, and the estimated VSL appeared as 796 million KRW/person. Conclusions There is a case in which the amount of statistical life value is estimated in connection with domestic environmental policy, fine dust, etc. However, there are no cases of evaluation for chemical. The utilization of this result is possible for conducting other study with chemicals.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.570-576
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• 2020

This study uses beacons and smartphone Global Positioning System (GPS) receivers to establish a location-based disaster/hazard prediction system. Beacons are usually installed indoors to locate users using triangulation in the room, but this study is differentiated from previous studies because the system is used outdoors to collect information on registration location and temperature and humidity in hazardous areas. In addition, since it is installed outdoors, waterproof, dehumidifying, and dustproof functions in the beacons themselves are required, and in case of heat and humidity, the sensor must be exposed to the outside, so the waterproof function is supplemented with a separate container. Based on these functions, information on declining and vulnerable areas is identified in real time, and temperature/humidity information is collected. We also propose a system that provides weather and fine-dust information for the area concerned. User location data are acquired through beacons and smartphone GPS receivers, and when users transmit from declining or vulnerable areas, they can establish the data to identify dangerous areas. In addition, temperature/humidity data in a microspace can be collected and utilized to build data to cope with climate change. Data can be used to identify specific areas of decline in a microspace, and various analyses can be made through the accumulated data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.4
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• pp.795-804
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• 2009

An HSS(Home Subscriber Server) system requires a main-memory database on main-memory unit for the real-tine management of the subscriber information in the mobile communication service, in that the system controls not only basic data for handling calls of users, but also additional service data related to user authentication and operational data. Nonetheless, HSS-DBS system, requiring the reliability and stability, need more secure data store method and a back-up technique because the system have a long startup time and the big problem on the failures of main-memory. This paper proposes an efficient back-up replication technique, on the basis of enhancing the stability and performance of HSS system. The proposed shadowing back-up technique adopting the delayed recovery process, can help minimize the real-time back-up overloads by location registration, while the proposed backup replication method enables more stable system operations with replicating the data to remote server in real time.

• The Journal of the Korea Contents Association
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• v.6 no.3
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• pp.46-54
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• 2006

Various schemes for mobility are currently studied in ITU-T, 3GPP, IETF, and so on. Mobility support in NGN for seamless service is necessarily required. Currently proposed mechanisms are MIPV6,0, Q.MMF, and IMS. However the performance comparison of all existing schemes is not examined as yet. That is, the existing methods need to be compared according to each performance parameter. So, in this paper, we investigate and compare the performances of MIPv6,0, Q.MMF, IMS to location registration. In addition, this paper presents the performance comparison of handover latency times. For this, we use NS-2 simulator. As a result of analysis, Q.MMF shown the best performance as it is measured the minimum time and cost. And it has low handover latency time in comparison with other mechanisms.