• Journal of Korean Institute of Industrial Engineers
• /
• v.34 no.2
• /
• pp.160-171
• /
• 2008

MU's mobility patterns can be found from a movement history data. The prediction accuracy and model complexity depend on the degree of application of history data. The more data we use, the more accurate the prediction is. As a result, the location management cost is reduced, but complexity of the model increases. In this paper, we classify MU's mobility patterns into four types. For each type, we find the respective optimal number of application of history data, and predictive location area by using the simulation. The optimal numbers of four types are shown to be different. When we use more than three application of history data, the simulation time and data storage are shown to increase very steeply.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2007.11a
• /
• pp.388-394
• /
• 2007

In wireless network, we propose a predictive location update scheme which considers mobile user's(MU's) mobility patterns. MU's mobility patterns can be found from a movement history data. The prediction accuracy and model complexity depend on the degree of application of history data. The more data we use, the more accurate the prediction is. As a result, the location management cost is reduced, but complexity of the model increases. In this paper, we classify MU's mobility patterns into four types. For each type, we find the respective optimal number of application of history data, and predictive location area by using the simulation. The optimal numbers of four types are shown to be different. When we use more than three application of history data, the simulation time and data storage are shown to increase very steeply.

• Journal of information and communication convergence engineering
• /
• v.7 no.4
• /
• pp.489-495
• /
• 2009

Geographic routing has attracted many researcers with no need for routing table to forward packet in mobile ad hoc networks. Previously, some literatures have mentioned how to improve the performance via simulation results. However, they didn't address the impact of various mobility models and beacon interval, which is used to maintain recent position information for nodes. In this paper, we introduce well-known geographic routing protocol called as GPSR and conduct simulation to identify the impact of these parameters. Even though GPSR shows acceptable performance in most cases, sometimes its performance becomes worse than what we expect.

• International Commerce and Information Review
• /
• v.9 no.2
• /
• pp.87-101
• /
• 2007

This study developed seven assumptions to demonstrate the effect of personal innovation, social influences, service quality, mobility and accessibility on perceived usability, perceived convenience use and use intention using a technology acceptance model developed by Davis(1989), and the results are presented as follows: First, the assumption that personal innovation and service quality of mobile banking service will influence the perceived usability was adopted while the assumption that social influences will affect the perceived usability was rejected. Second, the assumption that mobility and accessibility of mobile banking services will influence the perceived convenient use was selected. Third, the assumption that the perceived usability of mobile banking service will influence use intention was rejected while the assumption that the convenient use will influence use intention was adopted. This study suggests that as personal innovation, service quality, mobility and accessibility have a significant influence on use of mobile banking, service providers should pay more attention to development of security programs and diversification of contents.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.2 no.2
• /
• pp.55-58
• /
• 1988

Electron mobility which is a basic parameter to represent gas state, is calculated for 38mm 20W fluorescent lamp. 2 Electron Group Model is u&ed for electron distribution function. To prove this result electron mobility in 38mm 20W fluorescent lamp is measured at various wall temperatures. In order to obtain electric field strength of positive column, the sum of anode and cathode fall voltages assumed to be 15(VJ) and dual slit is used to measure positive column length. The measured and calculated result is potted under $10-80^{\circ}C$ wall temperature.

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

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.11A
• /
• pp.1051-1058
• /
• 2010

Mobile IP (MIP) and SIP are considered as important technologies to provide the macro mobility in the next generation mobile convergence networks which have heterogeneous access networks. Typically, MIP and SIP are more suitable for the non-real-time TCP connections and the real-time RTP/UDP sessions respectively, hence a handset which uses both of these sessions should simultaneously apply MIP and SIP to perform the efficient mobility management. Existing multi-layered mobility management schemes focus on the signalling order of each protocol. However, simple combining of two protocols cannot provide the performance enhancement of the mobility management. In this paper, a novel multi-layered mobility management algorithm using the combination of SIP and fast MIPv6 (FMIPv6) is proposed. FMIPv6 and SIP mobility is simultaneously performed to reduce the service interrupt time and to guarantee QoS requirement. The delay model is defined to analysis the performance of the algorithm and the simulation results show the performance of the proposed algorithm.

• Journal of Internet Computing and Services
• /
• v.14 no.3
• /
• pp.67-79
• /
• 2013

In wireless networks, efficient mobility management to support of mobile users is very important. Several mobility management schemeshave been proposed with the aim of reducing the signaling traffic of MN(Mobile Node). Among them, PMIPv6 (Proxy Mobile IPv6) is similar with host-based mobility management protocols but MN does not require any process for mobility. By introducing new mobile agent like MAG (Mobile Access Gateway) and LMA (Local Mobility Anchor), it provides IP mobility to MN. In this paper, we propose the analytical model to evaluate the mean signalingdelay and the mean bandwidth according to the type of MN mobility. As a result of mathematical analysis, MF-PMIP (Multicasting-based FastPMIP) outperforms compared to F-PMIP and PMIP in terms of parameters for the performance evaluation.

• Journal of Astronomy and Space Sciences
• /
• v.26 no.4
• /
• pp.677-692
• /
• 2009

In recent years, lots of studies on the planetary rover systems have been performed around space advanced agencies such as NASA, ESA, JAXA, etc. Among the various technologies for the planetary rover system, the mobility system, navigation algorithm, and scientific payload have been focused particularly. In this paper, the conceptual design for a ground-based model of planetary rover's mobility system to evaluate mobility and moving stability on ground is presented. The status of overseas research and development of the planetary rover systems is also addressed in terms of technical issues. And then, the requirements of the planetary rover's mobility system are derived by means of considering mobility and stability. The designed rover's mobility system has an active suspension with 6 legs that controls 6 joints on the each leg in order to achieve high stability and mobility. This kind of mobility system has already applied to the ATHELE of NASA for various purposes such as transportation and habitation for human lunar exploration activities in the near future (i.e., Constellation program). However, the proposed system has been designed by focusing on the small-sized unmanned explorations, which may be applied for the future Korea Lunar exploration missions. Therefore, we expect that this study will be an useful reference and experience in order to develop the planetary exploration rover system in Korea.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.1
• /
• pp.61-77
• /
• 2017

The most challenging issues in the multi-channel MAC of the IEEE 1609.4 standard is how to handle the dynamic vehicular traffic condition with a high mobility, dynamic topology, and a trajectory change. Therefore, dynamic channel coordination schemes between CCH and SCH are required to provide the proper bandwidth for CCH/SCH intervals and to improve the quality of service (QoS). In this paper, we use a Markov model to optimize the interval based on the dynamic vehicular traffic condition with high mobility nodes in the multi-channel MAC of the IEEE 1609.4 standard. We evaluate the performance of the three-dimensional Markov chain based on the Poisson distribution for the node distribution and velocity. We also evaluate the additive white Gaussian noise (AWGN) effect for the multi-channel MAC coordination scheme of the IEEE 1609.4 standard. The result of simulation proves that the performance of the dynamic channel coordination scheme is affected by the high node mobility and the AWGN. In this research, we evaluate the model analytically for the average delay on CCHs and SCHs and also the saturated throughput on SCHs.