• 대한전자공학회논문지TC
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• 제49권5호
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• pp.77-83
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• 2012

다양한 서비스와 네트워크의 융합이 가속화되면서 이종 네트워크별 효과적 이동성 관리에 대한 중요성이 부각되고 있다. 본 논문에서는 이종 네트워크 중 이동 IP 네트워크의 구조에 적합한 이동성 모델을 고려하고 주어진 환경 하에서 사용자 이동에 따른 다양한 성능평가와 관련된 지수를 도출하고 이를 활용하기 위한 방안을 제시한다. 또한 미래의 스마트 인지 네트워킹 환경 하에서는 개별 사용자의 이동성이 체계적으로 관리되어야 네트워크 자원의 효율적 활용과 무선 접속을 위한 주파수 스펙트럼의 효과적 활용에 매우 중요하다. 기존의 이동성 모델은 개별 네트워크 측면에서 다루어지면서 새로운 융합 이종 네트워크 환경에 적용하는데 적합성이 낮으므로 새로운 이동성 모델을 고려하여 융합 네트워크의 성능을 평가하는데 유용할 것으로 기대된다.

• Journal of Communications and Networks
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• 제6권4호
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• pp.352-361
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• 2004

In this paper, we study how to achieve the maximum capacity under delay constraints for large mobile wireless networks. We develop a systematic methodology for studying this problem in the asymptotic region when the number of nodes n in the network is large. We first identify a number of key parameters for a large class of scheduling schemes, and investigate the inherent tradeoffs among the capacity, the delay, and these scheduling parameters. Based on these inherent tradeoffs, we are able to compute the upper bound on the maximum per-node capacity of a large mobile wireless network under given delay constraints. Further, in the process of proving the upper bound, we are able to identify the optimal values of the key scheduling parameters. Knowing these optimal values, we can then develop scheduling schemes that achieve the upper bound up to some logarithmic factor, which suggests that our upper bound is fairly tight. We have applied this methodology to both the i.i.d. mobility model and the random way-point mobility model. In both cases, our methodology allows us to develop new scheduling schemes that can achieve larger capacity than previous proposals under the same delay constraints. In particular, for the i.i.d. mobility model, our scheme can achieve (n-1/3/log3/2 n) per-node capacity with constant delay. This demonstrates that, under the i.i.d. mobility model, mobility increases the capacity even with constant delays. Our methodology can also be extended to incorporate additional scheduling constraints.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권2호
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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.

• International journal of advanced smart convergence
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• 제8권3호
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• pp.78-86
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• 2019

Recently, IoT researches using sensor data based on embedded networks in various fields including healthcare and sports have been continuously attempted. This study analyzes golf ball mobility to support IoT application in golf sports field. Generally, since the difference in density occurs due to the condition of the inner material and the abnormal state at the time of the outer skin joining during the manufacturing of the golf ball, the weight of each subset is equal for any two points with the same radius in the sphere cannot be guaranteed. For this reason, the deflected weight of the sphere has the undesirable effect of hitting the ball in a direction in which the weight of the ball is heavy. In this study, it is assumed that there is a unique center of gravity of the ball, and even if the golf ball cannot be manufactured perfectly, it wants to establish the basic principle to accurately recognize or mark the putting line based on the center of gravity. In addition, it is evaluated how the mobility of the golf ball with a deviation from the center of gravity of the golf ball affects the progress path (or movement direction) and the moving distance (or carry distance) after the golfer hits. The basic model of the mobility of the golf ball can help the golfer exercise model and the correlation analysis. The basic model of the mobility of the golf ball can help the golfer exercise model and the correlation analysis.

• 한국수소및신에너지학회논문집
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• 제34권5호
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• pp.478-489
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• 2023

In this study, fault diagnosis and detection methods developed to ensure the reliability of polymer electrolyte membrane (PEM) hydrogen electrolysis systems have been proposed. The proposed method consists of model development and data generation of the PEM hydrogen electrolysis system, and data-driven fault diagnosis learning model development. The developed fault diagnosis learning model describes how to detect and classify faults in the sensors and components of the system.

• Journal of Communications and Networks
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• 제11권4호
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• pp.337-349
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• 2009

In this paper, we introduce a novel mobility model for mobile sinks in which the sinks move towards randomly distributed destinations, where each destination is associated with a mission. The novel mobility model is termed the random mobility with destinations. There have been many studies on mobile sinks; however, they merely support two extreme cases of sink mobility. The first case features the most common and general mobility, with the sinks moving randomly, unpredictably, and inartificially. The other case takes into account mobility only along predefined or determined paths such that the sinks can gather data from sensor nodes with minimum overhead. Unfortunately, these studies for the common mobility and predefined path mobility might not suit for supporting the random mobility with destinations. In order to support random mobility with destination, we propose a new protocol, in which the source nodes send their data to the next movement path of a mobile sink. To implement the proposed protocol, we first present a mechanism for predicting the next movement path of a mobile sink based on its previous movement path. With the information about predicted movement path included in a query packet, we further present a mechanism that source nodes send energy-efficiently their data along the next movement path before arriving of the mobile sink. Last, we present mechanisms for compensating the difference between the predicted movement path and the real movement path and for relaying the delayed data after arriving of the mobile sink on the next movement path, respectively. Simulation results show that the proposed protocol achieves better performance than the existing protocols.

• 한국컴퓨터정보학회논문지
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• 제10권2호
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• pp.133-141
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• 2005

무선 이동 통신망에서 위치관리에 대한 성능분석을 위해서 사용자의 이동 패턴의 모의실험 방안에 대한 연구가 요구되고 있다. 이러한 목적에 따라 본 논문은 무선 이동 망에서의 이동패턴을 갖는 사용자의 이동성 모델을 제안한다. 이동 사용자들은 임의적으로 움직이기도 하지만 특정 시간대에 규칙적인 이동을 반복하는 특성도 함께 가지고 있다. 따라서 제안된 모델은 사용자의 시간에 연관된 이동을 묘사하도록 구성하였다. 이 모델은 지점 이동, 타임 슬롯에 대한 이동확률, 이동에 대한 지형적 경로 등으로 구성된다. 또한 임의적인 이동과 규칙적인 이동 특성이 혼합된 경우에 대한 모의실험 방안도 함께 제안된다. 모의실험 결과는 의도했던 이동패턴을 갖는 이동 시나리오를 생성할 수 있음을 보여준다.

• 전기학회논문지
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• 제65권2호
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• pp.253-256
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• 2016

In this paper, the power system with electric vehicles is analyzed considering the mobility and diffusion rate of electric vehicles in the smart grid environment. In the previous studies, load modeling and load composition rates have been researched and the results are applied to develop a new load model to explain the mobility of electric vehicles which could affect on the power system status such as power flow and stability. The results would be utilized to research and develop power system analysis methods considering movable charging characteristics of electric vehicles including movable discharging characteristics which could be affected by the diffusion progress of electric vehicles.

• 한국산업정보학회논문지
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• 제11권2호
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• pp.1-8
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• 2006

본 논문은 이동망에서 위치등록 방식에 따른 성능평가에 관한 것이다. 먼저 거리기반 위치등록 방식을 제안하고, 이를 이동망 모델에 적용하여 성능을 평가하였다. 제안한 방식과 기존의 지역기반 위치등록 방식과의 성능을 비교, 평가한 결과, 거리기반 위치등록 방식은 지역기반 위치등록 방식과 위치 등록에 따른 부하는 대동소이하나 주어진 지역내에서 모든 셀들이 고르게 분포하여 주파수 자원이 효율적으로 사용됨을 알 수 있다.

• 산업경영시스템학회지
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• 제29권1호
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• pp.18-25
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• 2006

In mobile ad-hoc networks(MANETs), nodes are mobile and network topology changes very frequently. The mobility of nodes does affect the system performance. There has been considerable attention on the mobility models, however, most work is confined to the simulation or test-bed. In this paper, we propose an analytical method to evaluate the performances of MANETs such as the average radio range dwell time of mobile nodes, link holding time, and transmission failure probability considering the node's mobility. In the proposed model, MANETs consist of the multi-hop and multicasting routing paths. A simulation is done to validate our proposed analytical model.