• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3A
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• pp.287-295
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• 2010

In wireless sensor networks(WSNs), the studies that support sink mobility without global position information exploit a Backbone-based Virtual Infrastructure (BVI) which considers one-hop clusters and a backbone-based tree. Since the clusters of a sink and a source node are connected via flooding into the infrastructure, it causes high routing cost. Although the network could reduce the number of clusters via multi-level clusters, if the source nodes exist at nearest clusters from the cluster attached by the sink and they are in different branches of the tree, the data should be delivered via detour paths on the tree. Therefore, to reduce the number of clusters, we propose a novel multi-hop cluster based communication protocol supporting sink mobility without global position information. We exploit a rendezvous cluster head for sink location service and data dissemination but the proposed protocol effectively reduces data detour via comparing cluster hops from the source. Simulation shows that the proposed protocol is superior to the existing protocols in terms of the data delivery hop counts.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.39-42
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• 2003

Due to the highly dynamic topology and absence of any fixed infrastructure, stability of selected path in Ad Hoc Networks is of prime importance. The frequent route failure and high control overhead in routing protocol consumes system resources and lead to degraded system performance. In this paper we present route stability metrics reflectting relative position and velocity of nodes, which help determine a stable route.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.9
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• pp.457-464
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• 2005

In this paper a 3D memory system that allows 17 access types at an arbitrary position is introduced. The proposed memory system is based on two main functions: memory module assignment function and address assignment function. Based on them, the memory system supports 17 access types: 13 Lines, 3 Rectangles, and 1 Hexahedron. That is, the memory system allows simultaneous access to multiple data in any access types at an arbitrary position with a constant interval. In order to allow 17 access types the memory system consists of memory module selection circuitry, data routing circuitry for READ/WRITE, and address calculation/routing circuitry In the point of view of a developer and a programmer, the memory system proposed in this paper supports easy hardware extension according to the applications and both of them to deal with it as a logical three-dimensional away In addition, multiple data in various across types can be simultaneously accessed with a constant interval. Therefore, the memory system is suitable for building systems related to ,3D applications (e.g. volume rendering and volume clipping) and a frame buffer for multi-resolution.

• Journal of Advanced Navigation Technology
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• v.13 no.4
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• pp.551-558
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• 2009

Most of clustering schemes focusing on the energy efficiency have only a cluster head in each cluster, thus the energy consumption of cluster head in a cluster can rapidly increase. To reduce the energy consumption, recently, the dual-layered clustering which is separated a cluster ranges into two parts, i.e., data aggregation layer and data transmission layer, based on a sensor equipped with geographical positioning system (GPS), was proposed. However, the logical regions existing within the dual-layered clustering range can not distinguish efficiently. This scheme leads to many messages collision and transmission delay among member nodes. In this paper, to solve these problems, we propose a separated dual-layered routing scheme using the position information and the cluster radius. Proposed scheme clearly distinguish the dual-layered clustering range and gets the balanced number of member nodes in each cluster. Therefore, the proposed routing scheme could prolong the overall network life time about 10% compared to the previous two layered clustering scheme and LEACH.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.11
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• pp.1148-1161
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• 2012

Recently, developments in the field of communication and network technologies induced new paradigm in the defense weapon system. As a consequence, military authorities develop the Tactical Information Communication Network(TICN) system to adapt to the changing paradigm. One of the most important functions of TICN is real-time communication. As a result, TICN system needs to receive real-time information from the battlefield, and the key technology to support these features is MANET(Mobile Ad-Hoc Network) routing protocol. In this paper, we analyze problems of the shortest path scheme in tactical Ad-Hoc networks, which is widely used in common Ad-Hoc networks. We propose efficient routing protocol for tactical MANET by considering the environment of small combat units, such as node position, speed and data size. The proposed algorithm shows reliable data transfer and low latency in battlefield.

• Journal of the Korea Society of Computer and Information
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• v.15 no.2
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• pp.147-154
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• 2010

This paper suggests new route plan cost calculation and cost-effective route plan algorithm and architecture for the new city traffic information system when it is operated nationwide. New algorithm and architecture estimates cost with traffic speeds which is supported for all different lanes, stratifies logical layer which process different levels' traffic information with diverse traffic patterns and provides different traffic information in the few levels. Also suggested new algorithm supports drivers' customized traffic information through both-way communications and plans routes effectively based on the distance between drivers' start position and destination and different levels which start and end position located. It proposes additional research items and requirement for integration between different cities' traffic information system which the national police agency invested and led.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.849-851
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• 2003

A location-based service or LBS in a cellular telephone network is a service provided to the subscriber based on his current geographic location. This position can be known by user entry or a GPS receiver that he carries with him, but most often the term implies the use of a function built into the cell network that uses the known geographic coordinates of the base stations through which the communication takes place. One implication is that knowledge of the coordinates is owned and controlled by the network operator, and not by the end user. Location utility service provides two kinds of functions, geocoder and reverse geocoder. Geocoder converts an address into a coordinate and reverse geocoder changes a coordinate into an address. Because location utility service is the first step to progress LBS, various servises such as directory, routing, presentation, and etc require to access that. In this paper, we will describe the architecture of LBS platform and the concept and the role of location utility service.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5A
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• pp.407-416
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• 2005

This paper suggests a new geocasting protocol which is used to transfer the geographic packets to the specific region in MANET. Geocasting protocol is basically different from the conventional multicasting protocol that needs group addition and maintenance. A geocasting protocol using the mobile node's position information is the new area of multicasting protocols. The existing geocasting protocols have the following problems; it may be impossible to transfer data to some mobile hosts even if there are alternate routes and they have low adaptability and efficiency when the number of mobile hosts increases. The proposed CBG (Cluster-Based Geocasting) uses the proactive routing strategy and clustering technique with mobile host's location information. The CBG achieves high successful data transmission ratio and low data delivery cost to mobile hosts at specific region.

• Journal of Information Technology Applications and Management
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• v.26 no.5
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• pp.41-56
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• 2019

Recently great loss of life and property is occurring because of fire, natural disaster, earth quake, tsunami and so on. People spend 80~90% of their time indoor environment like office, supermarket, campus. Therefore Indoor navigation and guidelines system became so essential for most of all. Incase of emergency we must be careful earlier, in such a cases 5G kind of new technology may also cannot work. So immediate action and quick routing notification for guidelines and protection is the most. Considering this issue We proposed indoor evacuating guidance system based on microcontroller Wi-Fi board for Indoor APP using mobile. Focusing various kind of technology like, ok google, voice search APP we purposed node architecture based system. When we listen fire alarm while living inside the room. Then to be safe we connect with server and start Arduino UNO+IoT ESP8266 Wi-Fi shield version1-IoT module to store data in MySQL DB server. We make application to escape out from the building up-to the three exits giving information from source point to destination. Our program can send information to the users emergency location and situations. For this when the user get sound or vibration in their mobile device it indicate fire out near by. At that time we update message from Arduino to DB server for the fixed current position inside the building which give routing signal for that fire out location by changing values from 0 to 1. We have user in point 10 where user is near by. Later we detect Wi-Fi signal form Nodemcu as room of each floor and try to connect with user. Main purpose of this paper is to save life of people in short time and find out the shortest path up to nearest exits in the time of emergencies and rescue them.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.4
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• pp.61-68
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• 2009

In this paper, we propose a Cluster-based Cooperative Routing using ARQ (CCRA) for supporting both reliability and transmitting efficient service in mobile ad-hoc wireless sensor networks with Rayleigh fading environments. The main contributions and features of this paper are as follows. First, the clustering method which uses the position information of nodes as underlying structure for supporting reliable transmission services is used. Second, the cooperative data transmission method based on the underlying clustering informations is used to improve both reliability and data transmission efficiency. Third, the ARQ-based transmission is used to improve transmission reliability. Fourth, we consider a realistic approach, in the points of view of mobile ad-hoc wireless sensor networks, based on mobile sensor nodes as well as fixed sensor nodes in the sensor fields while the conventional research for sensor networks focus on mainly fixed sensor networks. The performance evaluation of proposed routing protocol implemented via simulation using Optimized Network Engineering Tool (OPNET) and theoretical analysis.