• Journal of Communications and Networks
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• v.7 no.2
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• pp.207-221
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• 2005

The proliferation of wireless local area networks (WLANs) offering high data rate in hot spot area have spurred the demand for possible WLANs and third-generation (3G) cellular network integration solutions as the initiative step towards 4G systems. This paper provides a novel architecture for seamless location-aware integration of WLANs into 3G cellular networks and also an analysis for the efficient handover techniques. We introduce location as a key context in secure roaming mechanism for context-aware interworking in 4G systems. The fast secure roaming with location-aware authentication is implemented at an entity called location-aware service (LAS) broker that utilizes the concepts of direction of user and pre-warming zone. The location-ware interworking architecture supports seamless roaming services among heterogeneous wireless networks including WLANs, wireless metropolitan area networks (WMANs), and 3G cellular networks. This paper also includes a description of procedures needed to implement efficient mobility and location management. We show how the LAS broker with pre-warming and context transfer can obtain significant lower latency in the vertical handover.

• Journal of Korea Port Economic Association
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• v.21 no.3
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• pp.19-34
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• 2005

The purpose of this paper is to introduce the new way of location choice for free trade zone in Busan area by using Obata and Ishii(2003) model of preference discrimination score. And also, this paper investigates the result of Choi, Bong-ho(200l) that deals with the choice of tariff free area in Busan area. Empirical main results are as follows: First, the North Port(Sinsundae)and the New Busan Port are efficient. Final winer of location choice for free trade zone is the North Port(Sinsundae). Second, the ranking result of this paper for 10 potential sites of free trade zone shows the almost similar to that of Choi, Bong-ho(200l). Policy planner for location choice of free trade zone should introduce the preference discrimination score method by Obata and Ishii(2003), because this method shows the very positive empirical results like questionaire method by expert groups and common people in Busan which should cause the much time and much money.

• Journal of Navigation and Port Research
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• v.43 no.5
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• pp.289-295
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• 2019

In this paper, we implemented a safety navigation mobile application that converged AtoN information and location-based services. When application user uses the smartphone's GPS sensor to transmit the user's vessel location data to the data server, the user receives information of which its providing range is considered, such as stored AtoN data, neighboring vessels information, danger area, and weather information in the server. Providing information is sorted based on the smartphone's direction and inclination and it will be also delivered via wireless network (5G, LTE, 3G, WiFi). Additionally the application is available to implement other functions such as information provision through voice and text alarming service when the user's vessel is either approaching or entering the danger area, and an expanded information provision service that is available in shadow area linking with data-storing methods; other linkable data such as weather and other neighboring vessels will be applied based on the lasted-saved data perceived from the non-shadow area.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.397-401
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• 2006

In this paper, we proposed a high precision location estimation algorithm using an enhanced decision scheme for RTLS and analyzed its performance in point of an average estimation error distance at 2D coordinates searching area, $300m\times300m$ and LOS propagation environments. Also the performance was compared with that of conventional TDOA algorithm according to the number of available reader and received sub-blink. From the results, we confirmed that the proposed location estimation algorithm using an enhanced decision scheme was able to improve an estimation accuracy even in boundary region of searching area. Moreover, effectively reduced an error distance in entire searching area so that increased the stability of location estimation in RTLS. Therefore, we verified that the proposed algorithm provided a more higher estimation accuracy and stability than conventional TDOA.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.2
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• pp.46-53
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• 2016

In mobile communication systems, location management deals with the location determination of users in a network. One of the strategies used in location management is to partition the network into location areas. Each location area consists of a group of cells. The goal of location management is to partition the network into a number of location areas such that the total paging cost and handoff (or update) cost is a minimum. Finding the optimal number of location areas and the corresponding configuration of the partitioned network is a difficult combinatorial optimization problem. This cell grouping problem is to find a compromise between the location update and paging operations such that the cost of mobile terminal location tracking is a minimum in location area wireless network. In fact, this is shown to be an NP-complete problem in an earlier study. In this paper, artificial bee colony (ABC) is developed and proposed to obtain the best/optimal group of cells for location area planning for location management system. The performance of the artificial bee colony (ABC) is better than or similar to those of other population-based algorithms with the advantage of employing fewer control parameters. The important control parameter of ABC is only 'Limit' which is the number of trials after which a food source is assumed to be abandoned. Simulation results for 16, 36, and 64 cell grouping problems in wireless network show that the performance of our ABC is better than those alternatives such as ant colony optimization (ACO) and particle swarm optimization (PSO).

• Journal of KIISE:Information Networking
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• v.31 no.3
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• pp.289-297
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• 2004

State-of-the-art wireless communication networks allow dynamic relocation of mobile terminals. A location management mechanism is required to keep track of a mobile terminal for delivering incoming calls. In this paper, we propose a fuzzy logic-based selective paging method to reduce paging cost. In the proposed fuzzy logic-based location management method, the location update uses the area-based method that uses direction-based together with movement-based methods, and the location search uses the fuzzy logic-based selective paging method based on the mobility information of mobile terminals. A partial candidate paging area is selected by fuzzy control rules, then the fuzzy logic-based selective paging method pages only the cells within the partial candidate paging area. The performance of proposed fuzzy logic-based location management method is to be evaluated by both an analytical model and a simulation, and is compared with those of LA and BVP methods. From these evaluation results, we know that the proposed fuzzy logic-based location management method provide better performance than other location management methods.

• The Journal of the Korea Contents Association
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• v.14 no.4
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• pp.19-28
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• 2014

Recent advancements in the IT industry have made daily life more convenient than ever before. In particular, studies have focused on the position detection of individuals using the GPS in smartphones, and this application has been utilized actively in emergency rescue organizations. However, existing methods send the location information of a user to a predetermined guardian set by the user or to a control center when the user enters into or deviates from a predetermined space. Such spaces are created by an arbitrary radius, thereby making it difficult to set a detailed area by using an existing radius-area creation method in an unstructured space and path with a specific road, such as for trekking, amusement parks, or mountaineering. This study proposes a novel method for setting up an area by connecting multiple radii to improve the existing radius-area creation method in order to easily set a detailed area in smart devices or on the Internet. In addition, an optimization method for resource use is proposed by comparing the operation results in which a user's location is detected by using the proposed location-based area setup method and deviation detection.

• Spatial Information Research
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• v.12 no.2
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• pp.211-228
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• 2004

The purpose of this study is to analyze the sales area of gas stations to see the quality and the efficiencies of spatial distribution structure for petroleum products in Tae-jeon City. Location pattern of gas station is classified by factors of competitive facilities, transportation, population and landuse in Tae-jeon City. As a result, High profit pattern and low profit pattern is classified. The characteristics of the distribution pattern of gas station are that the while densely populated has a small sales area, the thinly populated region has huge ones. Location-allocation model is used in order to minimize the travel distance from consumer location to gas station and balance the spatial distribution of gas station in case studies. The result reveals that the model-based locations of gas stations are more dispersed and balanced in the whole Tae-jeon City compared with the actual location of gas stations. This study shows the characteristics and spatial distribution patterns of sales area and location in petroleum products distribution facilities.

• Journal of Biosystems Engineering
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• v.16 no.3
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• pp.211-218
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• 1991

In this study, the break of the rotary blade which is occured from a stress concentration of the inside of blade by the outside impulsive load, is analyzed to 3-dimension used by the Freezing Photoelastic Method. These results are as follows. 1. The bending and compression stress are the greatest at the location of blade case. 2. The section area of 3cm-location from the blade case is the smallest, therefore, there are breaked 58% of all at this location and are proofed to the most danger section 3. The section area which by stress concentration of 3cm-location from blade case is caused by the production of blade, and it was higher danger of break than another location's. 4. In the location of 6cm and 9cm from the blade case, the bending stress has received a little and the section area has larger than another's, so it is not almost possible that the break at that location 5. In order to prevent of break, the external part which has contacted soil have to made tender for receiving a little stress and the internal part which received a large stress have to strengthen.

• Korean Journal of Applied Biomechanics
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• v.23 no.1
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• pp.45-51
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• 2013

The current study developed the analysis program by employing the Polygon Clipping Algorithm to calculate the open area on the court when players try to spike a ball. The program consists of two kinds of output screen. First, on the main output screen, it is possible to calculate both blocked area by net and blockers, and opened area to avoid the blocked area when players spike the ball. Additionally, the secondary output screen shows the moving path of setter and the location of set. Main output screen indicates hitting points of spiking, blocking, and open area. Also, it is possible to analyze the movement of setter, location of set, and hitting point of attacker. The program was tested by comparing real coordinate value and location coordinate value which is operated on the program. To apply this program in the field, future study needs to develop the program that can calculate three dimensions coordinate fast by tracking the location of players or ball in real time.