• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2325-2330
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• 2005

A potential field method for solving the problem of path planning based on global and local information for a mobile robot moving among a set of stationary obstacles is described. The concept of various method used path planning is used design a planning strategy. A real human living area is constructed by many moving and imminence obstacles. Home service mobile robot must avoid many obstacles instantly. A path that safe and attraction towards the goal is chosen. The potential function depends on distance from the goal and heuristic function relies on surrounding environments. Three additional combined methods are proposed to apply to human living area, calibration robots position by measured surrounding environment and adapted home service robots. In this work, we proposed the application of various path planning theory to real area, human living. First, we consider potential field method. Potential field method is attractive method, but that method has great problem called local minimum. So we proposed intermediate point in real area. Intermediate point was set in doorframe and between walls there is connect other room or other area. Intermediate point is very efficiency in computing path. That point is able to smaller area, area divided by intermediate point line. The important idea is intermediate point is permanent point until destruction house or apartment house. Second step is move robot with sensing on front of mobile robot. With sensing, mobile robot recognize obstacle and judge moving obstacle. If mobile robot is reach the intermediate point, robot sensing the surround of point. Mobile robot has data about intermediate point, so mobile robot is able to calibration robots position and direction. Third, we gave uncertainty to robot and obstacles. Because, mobile robot was motion and sensing ability is not enough to control. Robot and obstacle have uncertainty. So, mobile robot planed safe path planning to collision free. Finally, escape local minimum, that has possibility occur robot do not work. Local minimum problem solved by virtual obstacle method. Next is some supposition in real living area.

• Journal of Digital Contents Society
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• v.3 no.2
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• pp.187-196
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• 2002

When mobile node moves into the different IP address area, the mobile node can be set the proper environment parameters automatically by DHCP. If we extend the DHCP option field to support the roles of home agent and foreign agent in mobile IP protocol, mobile node can perform the foreign address registration process of mobile IP protocol when DHCP IP environment is achieved automatically, too. DHCP is supplied in the PC with a series of Windows NT. This paper proposes and implements the functional blocks of extended DHCP nodes and this enables the DHCP node have a role of mobile IP agents without another protocol functional blocks.

• The Journal of Information Systems
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• v.15 no.4
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• pp.189-209
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• 2006

The progress of mobile internet technologies has changed user access to information. The mobile internet allows to obtain contents and services from wireless networks via mobile devices. The purpose of this study is th find out important factors that influence on the customer purchase intention by mobile internet environment. Base on TAM(Technology Acceptance Model) and the latest literature, a comprehensive set of constructs and hypotheses were compiled with a methodology for testing them. We suggested five factors that effect purchase intention in mobile internet environment: Enjoyment Ease of use, Usefulness, Mobility, Trust To validate the research model, we collected data from cellular phone user using an online survey. The results of this study are as follows. First enjoyment ease of un, usefulness, and mobility had positive effects on trust. Second, Usefulness, ease of use, and trust had positive effects on purchase intention to use mobile internet. Third, enjoyment and mobility did not have positive effects on purchase intention to use mobile internet. Based on these results, we suggest marketing strategies.

• Journal of Korean Institute of Industrial Engineers
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• v.26 no.4
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• pp.431-438
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• 2000

The purpose of this paper is to design the menu of mobile phone based on the impression engineering. Free response survey analysis was used to collect impression data on mobile phone functions with time interval. Simultaneity analysis was applied to finding the relationship among selected impression. We cluster a set of the related impression so as to design the menu of a mobile phone accordingly. This research is expected to contribute to the improvement of customer satisfaction by reflecting customer's impression in the process of product design.

• Korean Management Science Review
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• v.28 no.1
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• pp.1-10
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• 2011

One of the fundamental roles of web object navigation is to support what the user wants precisely and efficiently from the enormous web database to the web browser. As long as the web search results are a set of individual lists, it is all right to display each and every web result for the web browser to display a web object one by one. However, in case the search results are a collection of multiple interrelated web objects, then there is a need to represent for a new mechanism for linked web objects at a time. We define a unit of web objects derived from a Steiner tree where the web objects include a set of specific keywords calculated by the weight from which the solutions are extracted. Even if a web object does not include all the keywords, then the related hypertext linked web objects are derived and displayed onto the mobile web browser with meta data in one shot. In this paper, it is applied for the mobile browser that the web contents can dynamically be displayed with Steiner trees until each renewal of the navigation request may be issued. In this paper, a new synchronized mobile browsing method is developed so that the navigating time can drastically be reduced and the web navigating efficiency can be dramatically enhanced without sacrificing memory consumption.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6B
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• pp.411-419
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• 2008

As the set of new mobile data networking service technologies, such as WiBro, mobile WiMAX and WCDMA-HSDPA, have been introduced in recent years, IP mobility management protocols which aim to provide seamless IP service over the mobile networking environment become one of the important building blocks for the successful mobile networks. IETF has introduced a basic mobility management protocol over IPv6 (MIPv6) and a set of enhanced protocols such as FMIPv6 and HMIPv6, followed by FHMIPv6, S-MIPv6 and HIMIPv6 which combine the benefits of the basic protocols. We have studied the impact of the various IP mobility management protocols over TCP sessions through extensive simulations with ns-2. Our simulation results show that TCP performance with the HIMIPv6 outperforms MIPv6, FMIPv6 and HMIPv6 over the various TCP protocols, due to its efficient combination of the hierarchical mobility management scheme of the HMIPv6, the predictive handover scheme of the FMIPv6 and the fast simulcasting scheme of the S-MIP.

• Journal of Intelligence and Information Systems
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• v.13 no.1
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• pp.1-14
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• 2007

Character images for the background screen of cell phones are one of the fast growing sectors of the mobile content market. However, character image buyers currently experience tremendous difficulties in searching for desired images due to the awkward image search process. Content-based image retrieval (CBIR) widely used for image retrieval could be a good candidate as a solution to this problem, but it needs to overcome the limitation of the mobile Internet environment where an initial query set (IQS) cannot be easily provided as in the PC-based environment. We propose a new approach, IQS-AutoGen, which automatically generates an initial query set for CBIR on the mobile Internet. The approach applies the collaborative filtering (CF), a well-known recommendation technique, to the CBIR process by using users' preference information collected during the relevance feedback process of CBIR. The results of the experiment using a PC-based prototype system show that the proposed approach successfully satisfies the initial query requirement of CBIR in the mobile Internet environment, thereby outperforming the current image search process on the mobile Internet.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.5
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• pp.1069-1084
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• 2011

This paper considers an optimal base station clustering problem for designing a mobile (wireless) communication network. For a given network with a set of nodes (base stations), the problem is to optimally partition the set of nodes into subsets (each called a cluster) such that the associated inter-cluster traffic is minimized under certain topological constraints and cluster capacity constraints. In the problem analysis, the problem is formulated as an integer programming problem. The integer programming problem is then transformed into a binary integer programming problem, for which the associated linear programming relaxation is solved in a column generation approach assisted by a branch-and-bound procedure. For the column generation, both a heuristic algorithm and a valid inequality approach are exploited. Various numerical examples are solved to evaluate the effectiveness of the LP (Linear Programming) based branch-and-bound algorithm.

• Journal of Korea Multimedia Society
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• v.8 no.12
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• pp.1613-1622
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• 2005

Broadcasting is fundamental and effective data dissemination mechanism for route discovery, address resolution, and many other network services in mobile ad hoc networks. Although many approaches for broadcasting have been proposed to minimize the number of retransmissions, none of them guarantee the best-suited bounds of retransmissions. Appropriate use of probabilistic method can lower the chance of contention and collision among neighboring nodes, so that it reduces the number of rebroadcasts. In this paper, we propose a probabilistic approach that dynamically adjusts the rebroadcasting probability according to the distance between the sender and the receiver. While the rebroadcast probabilities of a mobile node close to sender will be set lower, the rebroadcast probabilities of a mobile node far away from sender wi1l be set to higher, The rebroadcast probability of a node wi1l be set according to the distance from sender. We evaluate the performance of proposed approach by comparing it with flooding as well as a fixed probabilistic broadcast approach. Simulation results showed that the performance of proposed scheme outperforms by about $70\%$ than flooding scheme and outperforms by about $20\%$ than fixed probabilistic scheme.

• The Journal of Information Systems
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• v.20 no.4
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• pp.103-117
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• 2011

The rapid pace of adoption of mobile handsets has created new mobile financial services. The success of mobile financial information systems will depend on consumer self-efficacy and a sound business model. Self-efficacy has been described as the belief that one is capable of performing in a certain manner to attain certain goals. This is directly related to consumer behavior, but it also affects consumer behaviors indirectly through its impact on goals. And self-efficacy influences the challenges that people take on as well as how high they set their goals. The objective of the study to investigates the effect of self-efficacy on mobile financial information systems. In order to do that, self-efficacy, mobile financial information systems reliability, mobile financial information systems use intensity are conceptualized by survey questionnaire. Our empirical analysis based on 462 survey data shows that self-efficacy effects on mobile financial information systems quality. In addition we also found that self-efficacy effects on mobile financial systems reliability and usage intention. And we found that mobile financial information systems reliability effects on mobile financial systems use intention. And we also found that mobile financial information systems usage intention effects mobile financial systems quality.