• Journal of Internet Computing and Services
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• v.12 no.3
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• pp.101-110
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• 2011

WMN is highlighted as a next generation network technology due to relatively reasonable cost to be built, compared with the pre-existing wireless network. It also enables same kind of network or even other kind of network to be integrated. Some WMN researches support mobility using router protocol such as AODV and DSR because WMN has the similar features with Ad-hoc network in terms of operation. However, WMN has got different operations with additional functions of multi-interface and internet connect, it can't be a good method to manage efficient mobility any more. This study suggests method to apply MAP function of HMIPv6 to WMN as a way to manage WMN mobility. Through simulation, operation was verified and function was appreciated. Through the results of evaluation, the suggest mobility management had shorter handover delay and packet loss reduced, which improved whole network throughput rate, compared with mobility management using AODV.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.481-487
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• 2023

Recently, interest in UAM (Urban Air Mobility) has surged as a critical solution to urban traffic congestion and air pollution issues. However, efficient UAM operation requires accurate 3D Point Cloud data processing, particularly in separating the ground and objects. This paper proposes and validates a method for effectively separating ground and objects in a UAM environment, taking into account its dynamic and complex characteristics. Our approach combines attitude information from MEMS sensors with ground plane estimation using RANSAC, allowing for ground/object separation that isless affected by GPS errors. Simulation results demonstrate that this method effectively operates in UAM settings, marking a significant step toward enhancing safety and efficiency in urban air mobility. Future research will focus on improving the accuracy of this algorithm, evaluating its performance in various UAM scenarios, and proceeding with actual drone tests.

• Journal of Preventive Medicine and Public Health
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• v.46 no.sup1
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• pp.50-54
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• 2013

Out-of-home mobility is necessary for accessing commodities, making use of neighborhood facilities, and participation in meaningful social, cultural, and physical activities. Mobility also promotes healthy aging as it relates to the basic human need of physical movement. Mobility is typically assessed either with standardized performance-based tests or with self-reports of perceived difficulty in carrying out specific mobility tasks. Mobility declines with increasing age, and the most complex and demanding tasks are affected first. Sometimes people cope with declining functional capacity by making changes in their way or frequency of doing these tasks, thus avoiding facing manifest difficulties. From the physiological point of view, walking is an integrated result of the functioning of the musculoskeletal, cardio-respiratory, sensory and neural systems. Studies have shown that interventions aiming to increase muscle strength will also improve mobility. Physical activity counseling, an educational intervention aiming to increase physical activity, may also prevent mobility decline among older people. Sensory deficits, such as poor vision and hearing may increase the risk of mobility decline. Consequently, rehabilitation of sensory functions may prevent falls and decline in mobility. To promote mobility, it is not enough to target only individuals because environmental barriers to mobility may also accelerate mobility decline among older people. Communities need to promote the accessibility of physical environments while also trying to minimize negative or stereotypic attitudes toward the physical activity of older people.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.2
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• pp.308-326
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• 2013

Mobility Model has drawn more and more attentions since its critical role in Mobile Wireless Networks performance evaluation. This paper analyzes the mobility patterns in the catastrophe rescue scenario, and proposes the Random Waypoint with Base Point mobility model to model these characteristics. We mathematically analyze the speed and spatial stationary distributions of the nodes and derive explicit expressions for the one dimensional case. In order to keep the stationary distribution through the entire simulation procedure, we provide strategies to initialize the speed, location and destination of the nodes at the beginning of the simulation. The simulation results verify the derivations and the proposed methods in this paper. This work gives a deep understanding of the properties of the Random Waypoint with Base Point mobility model and such understanding is necessary to avoid misinterpretation of the simulation results. The conclusions are of practical value for performance analysis of mobile wireless networks, especially for the catastrophe rescue scenario.

• Journal of information and communication convergence engineering
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• v.13 no.4
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• pp.248-256
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• 2015

With the dramatic increase in mobile traffic in recent years, some of the limitations of mobility management frameworks have magnified. The current centralized mobility management (CMM) strategy has various problems, such as a suboptimal routing path, low scalability, signaling overhead, and a single point of failure. To overcome these weaknesses in the CMM strategy, the Internet Engineering Task Force has been discussing distributed mobility management (DMM) strategies. The fundamental concept of a DMM strategy is to distribute the mobility anchors closer to the users. While the distribution of mobility anchors results in low-cost traffic delivery, it increases the signaling cost. To reduce this higher signaling cost, we propose a new DMM strategy applying the pointer forwarding technique. The proposed strategy keeps the existing tunnels and extends the traffic path as much as possible. In this paper, we analyze the performance of the pointer forwarding-DMM strategy and discuss its pros and cons.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.250-257
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• 2011

The power input to an infinite cylindrical shell excited by a point force is investigated. The circumferential direction and axial direction of the cylindrical shell is assumed as a two-dimensional unbounded medium, and the point force is replaced as a periodic array of imaginary sources. The spatial Fourier transform is taken from the equation of motion of the cylindrical shell, which is derived from the static model of Donell-Mushtari-Vlasov. The inverse Fourier transform is taken to derive the vibration responses. Mobility from out-of-plane forces and in-plane forces are derived from the obtained vibration responses. The theory is applied to a cylindrical shell excited by a normal direction of point force.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.12
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• pp.1128-1137
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• 2012

In this paper, we propose an improved MPR selection method considering mobility and density of nodes for ad-hoc networks. In Optimized Link State Routing(OLSR), a node selects 1-hop Multi-Point Relay(MPR) nodes to cover all 2-hop neighbor nodes. In a high population area, many nodes are likely to be selected as MPR nodes by their neighbors. This leads to increase in contention among MPR nodes and may decrease overall performance of the network. In addition, when an MPR node leaves the communication range of its MPR selector node, it can no longer perform as the MPR node and the performance of the network may also decrease. In this paper, we propose an MPR selection method which measures the mobility and density of nodes by exchanging the hello messages and gives the priorities to the nodes for MPR selection. Performance evaluation results using OPNET show that the proposed method is superior to OLSR or the MPR candidate method in terms of connectivity and throughput.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.159-162
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• 2006

In ubiquitous computing environments, which can be connected to the networks any time any where, wearable computers frequently will be changed their network connection point. Therefore, the demand of the mobility support service becomes more important. The mobility support mechanism allows a wearable computer to continue the existing services without the modification for the network configuration of wearable computer even if wearable computer changes the network connection point during its moving. In this paper, we design the component based middlewear for the mobility supports of wearable computers, propose the method of the mobility support service. This method tunnels the existing data to wearable computer using Mobile IP protocol even if a wearable computer moves to other network after recomposing dynamically the mobility support component in wearable middlewear.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.1
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• pp.40-44
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• 2013

The ball-shaped mobile robot, so called ballbot has single point contact on ground and low energy consumption in motion because of the reduced friction. In this paper, a new ballbot is presented, which has omnidirectional mobile platform inside of it as a driving system. Thus the ballbat has omnidirectional mobility without nonholonomic constraints. Kinematics and inverse kinematics of the ballbat is derived also in this paper.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.249-251
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• 1988

In this paper, the negative ion mobility of $SF_6$ is determined using as a negative ion detector the burst pulse which is triggered in a positive point-plane gap by electrons detached from negative ions near the anode point. The result obtained for the negative ion mobility for zero field at atmospheric pressure is $0.57cm^2v^{-1}s^{-1}$.