• Proceedings of the Korea Society for Simulation Conference
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• 2005.11a
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• pp.3-7
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• 2005

The structure of $IP^2$(IP based-IMT Network Platform) as ubiquitous platform is three-layered model : Middleware including NCPF(Network Control Platform) and SSPF(Service Support Platform), IP-BB(IP-Backbone), Access network including Sensor network. A mobility management(MM) architecture in NCPF is proposed for $IP^2$. It manages routing information and location information separately. The existing method of multicast control in $IP^2$ is Remote Subscription. But Remote Subscription has problem that should be reconstructed whole Multicast tree when sender moves. To solve this problem, we propose a way to put Multicast Manager in NCPF.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.85-87
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• 2003

최근 들어 이동통신 환경의 급격한 발달로 이를 활용한 위치기반 서비스에 대한 관심이 높아지고 있다. 효율적인 위치기반 서비스를 위해서는 실시간으로 위치를 변화시키는 이동객체에 대한 저장. 관리 및 질의를 담당할 수 있는 시공간 데이타베이스 관리 시스템의 존재가 필수적이다. 본 논문은 클러스터 기반 분산 컴퓨팅 구조를 바탕으로 제안된 시공간 데이타베이스 관리 시스템인 GALIS 구조 중에서 이동객체의 과거 위치 데이타를 디스크를 기반으로 저장 및 관리하는 노드인 LDP와 이동객체 데이터 생성기를 TMO 프로그래밍 스킴과 상용 데이타베이스 엔진을 사용하여 구현하였다. 제안 시스템은 대용량 이동객체의 효율적인 관리를 위한 실시간 엔진 개발에 활용될 수 있다.

• The KIPS Transactions:PartA
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• v.11A no.7 s.91
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• pp.529-536
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• 2004

Smart homes integrated with sensors, actuators, wireless networks and context-aware middleware will soon become part of our daily life. This paper describes a context-aware middleware providing an automatic home service based on a user's preference. The context-aware middle-ware utilizes 6 basic data for learning and predicting the user's preference on the multimedia content : the pulse, the body temperature, the facial expression, the room temperature, the time, and the location. The six data sets construct the context model and are used by the context manager module. The log manager module maintains history information for multimedia content chosen by the user. The user-pattern learning and pre-dicting module based on a neural network predicts the proper home service for the user. The testing results show that the pattern of an in-dividual's preferences can be effectively evaluated and predicted by adopting the proposed context model.

• Journal of Communications and Networks
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• v.8 no.4
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• pp.451-460
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• 2006

Since low earth orbit (LEO) satellite constellations have important advantages over geosynchronous earth orbit (GEO) systems such as low propagation delay, low power requirements, and more efficient spectrum allocation due to frequency reuse between satellites and spotbeams, they are considered to be used to complement the existing terrestrial fixed and wireless networks in the evolving global mobile network. However, one of the major problems with LEO satellites is their higher speed relative to the terrestrial mobile terminals, which move at lower speeds but at more random directions. Therefore, handover management in LEO satellite networks becomes a very challenging task for supporting global mobile communication. Efficient and accurate methods are needed for LEO satellite handovers between the moving footprints. In this paper, we propose a new seamless handover management scheme for LEO satellites (SeaHO-LEO), which utilizes the handover management schemes aiming at decreasing latency, data loss, and handover blocking probability. We also present another interesting handover management model called satellite mobility pattern based handover management in LEO satellites (PatHO-LEO) which takes mobility pattern of both satellites and mobile terminals into account to minimize the handover messaging traffic. This is achieved by the newly introduced billboard manager which is used for location updates of mobile users and satellites. The billboard manager makes the proposed handover model much more flexible and easier than the current solutions, since it is a central server and supports the management of the whole system. To show the performance of the proposed algorithms, we run an extensive set of simulations both for the proposed algorithms and well known handover management methods as a baseline model. The simulation results show that the proposed algorithms are very promising for seamless handover in LEO satellites.

• Journal of Internet Computing and Services
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• v.11 no.2
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• pp.85-98
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• 2010

An advanced and proactive response mechanism against diverse attacks on All-IP network should be proposed for enhancing its security and reliability on open network. There are two main research works related to this study. First one is the SPIE system with hash function on Bloom filter and second one is the Sinkhole routing mechanism using BGP protocol for verifying its transmission path. Therefore, advanced traceback and network management mechanism also should be necessary on All-IP network environments against DDoS attacks. In this study, we studied and proposed a new IP traceback mechanism on All-IP network environments based on existing SPIE and Sinkhole routing model when diverse DDoS attacks would be happen. Proposed mechanism has a Manager module for controlling the regional router with using packet monitoring and filtering mechanism to trace and find the attack packet's real transmission path. Proposed mechanism uses simplified and optimized memory for storing and memorizing the packet's hash value on bloom filter, with which we can find and determine the attacker's real location on open network. Additionally, proposed mechanism provides advanced packet aggregation and monitoring/control module based on existing Sinkhole routing method. Therefore, we can provide an optimized one in All-IP network by combining the strength on existing two mechanisms. And the traceback performance also can be enhanced compared with previously suggested mechanism.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.2
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• pp.15-24
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• 2016

GPS(Global Positioning System) location tracking is a method for taking the precise coordinates after the coordinates are obtained by a GPS receiver, and displaying them on the map. In this paper with WAVE(Wireless Access for Vehicular Environment) simulation, we show that various services such as vehicle tracking service, real-time road conditions service and logistics can go tracking service, control and operation services according to the vehicle position and the traveling direction by using the GPS position data. A vehicle tracking system using GPS is automatically able to manage multiple RCP when exchanging data between RMA and the RCP, and it provides rapid requests and responses. To verify that multiple sessions between RMA and RM, as well as multiple sessions between RMA and RCP are able to be implemented, we take RMA as a RCP application on an OBU, until the RMA is receiving data response from corresponding RM. As a result of this experiment, we show that the response speeds of single session between RMA and RM using 1, 2, 3, and 4 kbyte unit data are similar, 62.32ms, 62.65ms, 63.02ms, and 63.48ms, respectively. Likewise, those of 128 muliple sessions using 1, 2, 3, and 4 kbyte unit data are not much more time difference, 298.08ms, 302.21ms, 322.85ms, and 329.62ms, respectively.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.1
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• pp.103-112
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• 2000

As today's market share of Intelligent Network (IN) service and wireless tele-communication is growing rapidly, the increment in service requests of wireless IN service subscribers and users has to be taken into account for implementing advanced IN services. In this paper, we design Global Service Logic for IN Freephone service, which is one of the commercially most interesting IN services, applied call queuing service feature with mass call processing to enhance call completion rate by considering the mobility of wireless service subscribers with mobile terminals as well as existing wireline service subscribers. Due to the location management of each IN subscribers 'mobile terminals, we design the structure and operation mechanism of Queue Manager which adjusts dynamically service subscribers groups according to their mobility. We optimize the queue size according to the call attempt rate and drop rate, and present the appropriate waiting time in the queue.

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.2
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• pp.78-92
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• 2003

In related to mobile communication environment, many researchers have studied problems concerning current locations of mobile users and exposure of their movements in the privacy aspect so far [1,2,3,4,5,6,7,8,9]. Among them, Kesdogan and Pfitzmann [3,6] proposed effective solutions using temporary pseudonym identification, called TP(Temporary Pseudonym ) to solve them. After that, Kesdogan et al. proposed an improved method protecting mobile users from some types of attacks of network providers in [8]. However, among their methods, in particular the method, attaching the other new device (so-called Reachability Manager) to system against active attack of network providers, is alterative rather than practical and is not clear. Moreover, it requires the other cost and overhead. Therefore we propose a practical method against active attack of network providers without attaching new device in original environments. The basie idea of proposed method is to protect a fraud act of network provider as a inside user by exchanging a secret information, which only users and network providers know, via network provider between mobile user and the trusted third party (so-called Trust Device). Moreover, we introduce a new payment protocol which applied our method.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.1
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• pp.23-39
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• 2005

As developing satellite communication, the tracking range of the moving objects which move in local area is expanded to the whole world. However previous logistics management system is able to monitor freight which transporting in local area using mobile communication system. In this paper, we propose the reefer container management system that manages the location information and other related information such as temperature, humidity of container using the satellite system. The proposed system consists of three parts; data collector, satellite communication manager, reefer container information manager. And the proposed system uses the moving object index for managing the trajectory of container and tracing the location of container or vessel that is transporting the container, and supports various services such as reefer container and vessel tracking, container control and container statistics to logistic companies like shipper and forwarding agent. And the system can be increasing the quality of container transportation service to the shipper, and it makes the efficient management of reefer container to the shipping company.

• Journal of Advanced Navigation Technology
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• v.13 no.6
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• pp.971-976
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• 2009

This paper demonstrates the design and development of asset management systems suitable for the universities full of very various kind of assets. Universities consists of many departments, which have a multiplicity of many experimental. It is very difficult to record and manage assets with hands. In addition, the equipments are moving freely from one lab to another inside the school, which means it is tough to find the location of the assets and so some stuffs that are given lack attention are likely to disappear. So, these things occurring frequently in the university asset management environment should be considered in the design and embodiment of the asset management system. In the proposed system, location recognition of the assets is realized based on a route tracking method, so it is possible to detect the loss of the high priced assets and entrance, export, and lending of them are controlled efficiently. The system is likely to reduce the load of a manager responsible for asset management, because configured to decrease interventions of the manager in overall asset management process. Especially, the proposed system and implementation method will be suitable for small and medium-scale asset management, path tracking, history management.