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1.
We present different approaches for knowledge sharing bio-inspired mobile agents to obtain a uniform distribution of the nodes over a geographical terrain. In this application, the knowledge sharing agents in a mobile ad hoc network adjust their speed and directions based on genetic algorithms (GAs). With an analytical model, we show that the best fitness value is obtained when the number of neighbors for a mobile agent is equal to the mean node degree. The genetic information that each mobile agent exchanges with other neighboring agents within its communication range includes the node’s location, speed, and movement direction. We have implemented a simulation software to study the effectiveness of different GA-based algorithms for network performance metrics including node densities, speed, and number of generations that a GA runs. Compared to random-walk and Hill Climbing approaches, all GA-based cases show encouraging results by converging towards a uniform node distribution.  相似文献   

2.
The mobile agent paradigm has been adopted by several systems in the area of wireless sensor networks as it enables a flexible distribution and placement of application components on nodes, at runtime. Most agent placement and migration algorithms proposed in the literature, assume that the communication rates between agents remain stable for a sufficiently long time to amortize the migration costs. Then, the problem is that frequent changes in the application-level communication may lead to several non-beneficial agent migrations, which may actually increase the total network cost, instead of decreasing it. To tackle this problem, we propose two distributed algorithms that take migration decisions in an online fashion, trying to deal with fluctuations in agent communication. The first algorithm is more of theoretical value, as it assumes infinite storage to keep information about the message exchange history of agents, while the second algorithm is a refined version that works with finite storage and limited information. We describe these algorithms in detail, and provide proofs for their competitive ratio vs. an optimal oracle. In addition, we evaluate the performance of the proposed algorithms for different parameter settings through a series of simulated experiments, also comparing their results with those achieved by an optimal static placement that is computed with full (a posteriori) knowledge of the execution scenarios. Our theoretical and experimental results are a strong indication for the robustness and effectiveness of the proposed algorithms.  相似文献   

3.
The practicality of mobile agents hinges on realistic security techniques. Mobile agent systems are combination client/servers that transport, and provide an interface with host computers for, mobile agents. Transport of mobile agents takes place between mobile agent systems, which are located on heterogeneous platforms, making up an infrastructure that has the potential to scale to the size of any underlying network. Mobile agents can be rapidly deployed, and can respond to each other and their environment. These abilities expose flaws in current security technology. This article surveys the risks connected with the use of mobile agents, and security techniques available to protect mobile agents and their hosts. The inadequacies of the security techniques developed from the information fortress model are identified. They are the result of using a good model in an inappropriate context (i.e. a closed system model in a globally distributed networking computing base). Problems with commercially available techniques include: (1) conflicts between security techniques protecting hosts and mobile agents, (2) inability to handle multiple collaborative mobile agents, and (3) emphasis on the credentials of software instead of on the integrity of software to determine the level of trust.  相似文献   

4.
Mobile software agents: an overview   总被引:10,自引:0,他引:10  
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5.
The paper presents the basic ideas behind the use of software agent technology for distributed simulation and data assimilation. A software agent is an autonomous computer program that operates on behalf of someone or something. A mobile agent has the ability to migrate during execution from machine to machine in a heterogeneous network, while a stationary agent executes only on the system on which it began execution. To understand the role of agents in distributed simulation, note that simulations often operate on static datasets and data sources. Many simulations would produce more accurate results if they could access dynamically changing data from other sources, such as sensors or even other simulations. From the perspective of one simulation, other simulations are data resources, producing information possibly relevant to the past, present, or future of the system being modeled. Software agents allow dynamic linking between distributed simulations and efficient monitoring of and access to remote data resources. Specifically, they conserve bandwidth, provide custom operations without precompiling or preloading, and adapt to support disconnected operations. The paper describes the development of a software agent based framework for dynamically linking distributed simulations and other remote data resources. The framework called ABELS (Agent-Based Environment for Linking Simulations) allows independently designed simulations to communicate seamlessly with no a priori knowledge of the details of other simulations and data sources. We discuss our architecture and current implementation developed using the D'Agents mobile agent system  相似文献   

6.
随着网络和移动智能体技术的不断发展,如何在网络资源中找到自己需要的服务成为一个热门话题。描述以一种移动的多智能体系统,并且在进行系统底层通信、智能体在网络环境移动、智能体与服务器之间通信应用CORBA。服务器接受任务,派遣服务请求智能体在网络环境中寻找能为自己提供服务的服务器,完成向服务器预订服务任务。给出系统接受任务后派遣请求智能体的工作流程及服务器接受智能体访问的流程。  相似文献   

7.
Home agent is a key component of MIPv6 functionality that comprises binding cache to hold the mobile nodes current point of attachment to the Internet. This paper is concerned with binding cache support for home agents within MIPv6 network. Existing binding cache of home agent supports weak cache consistency by using fixed contract length for Binding Refresh Request, which functions reasonably well in normal situations. However, maintaining a strong binding cache consistency in home agent as a crucial exceptional handling mechanism has become more demanding for the following objectives: (i) to adapt increasingly frequent change of care‐of address due to mobile nodes movement detection update; (ii) to provide fine‐grain controls to balance the binding cache load distributions for better delivery services; and (iii) to reduce the overhead allowances around the binding cache. In this paper, we have first verified the effectiveness of Binding Refresh Request contract length, and on the basis of that, two dynamic contract algorithms are suggested to reduce the storage and communication overhead allowances in binding cache. We have also compared our technique with the existing fixed Binding Refresh Request contract length, and our simulation results reveals that the proposed approach provides an effective performance to reduce overhead within the network. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

8.
The use of mobile software agents is a promising approach to implement services and disseminate data over ad hoc networks. This paper presents an analysis of mobile autonomous agents with different levels of intelligence that allow them to make usage of the positioning information with different complexity in a mobile ad hoc network aiming at efficient data dissemination. This information considers the nodes current and future locations, as well as the route used to reach their destinations, depending on the agents’ intelligence. Using this information, the agents decide their movement from node to node during opportunistic connections in order to accomplish their goals related to data dissemination and/or service provisioning. The analysis of this proposal is done in the context of a sensor network application, implemented by sensing services provided by mobile agents, which run on top of an infrastructure-less Vehicular Ad hoc Network (VANET). Simulation results are presented and discussed to support the proposed ideas.  相似文献   

9.
This article proposes a network paradigm called the single-server-view network as the basis for networks in the 21st century, when the value of a network to users will be based on the services provided rather than data communication capability. Based on our paradigm, we propose a double-plane network architecture, consisting of a simplified data forwarding plane and a service control plane, that performs all the complex processing tasks. The data forwarding plane uses an advanced photonic network as its basis. The service control plane consists of agent, service, and policy control layers with open interfaces between layers. Leading-edge information processing technologies, such as active node, agent, distributed processing, and policy-based management, are used in this plane. Since mobile communication is becoming a major access technology, an approach to integrating mobile and fixed networks into this framework is also proposed. The current status of key technologies, such as photonic networks, agent technology, and policy-based management, are reported.  相似文献   

10.
The paper discusses the application of mobile agents in the management of mobile telephone (cellular) networks. We propose the use of mobile agents for collecting subscriber information, such as location area identifier and cell identifier. By using a subscriber profile containing these data the signaling messages caused by location update could be reduced. We also propose a method to improve the quality of network coverage by collecting measurements data by a mobile agent in the mobile station (mobile phone) or at the mobile switching center. By analyzing these data the network provider would be able to discover areas without proper radio signal coverage (black holes), thereby avoiding expensive and time-consuming measurements done by specially equipped vehicles. In addition, we discuss the basic infrastructure requirements for deployment of the mobile agent technology in cellular networks.  相似文献   

11.
通信机制是Agent技术研究的重要课题,该文在移动Agent主动通信算法的基础上,提出了一种改进的移动Agent主动通信算法,解决了可靠通信问题,通过设置时间变量和超速等待,在Agent高速移动的情况下,强迫Agent停止移动,避免消息长时间不能传递的问题,完成可靠的消息传递。  相似文献   

12.
车联网不同场景使用的通信技术有所不同。除了近距离通信技术外,属于中远距离通信技术的移动通信网络在V2I中扮演了重要的角色。但需要采取多种措施来弥补和完善以H2H通信为初始设计目标的移动通信网络的不足,以适应当前和未来车联网应用对中远距离通信的需求。基于此,本文提出了移动通信网络承载车联网应用的3个主要问题,并论述了通过多种网络的应用、终端和平台的改进、网络的简单优化以及实施特定的网络改进等方案来解决上述问题的思路。  相似文献   

13.
企业的信息化、智能化为移动代理的应用提供了广阔的平台,但是移动代理系统安全保障成为制约其应用的关键。从代理保护和代理平台保护两个方面阐述了移动代理系统关键信息安全保障技术,分析了移动代理安全标准化现状,提出了未来移动代理安全保障技术及标准化研究建议。  相似文献   

14.
We present MAGICS, a mobile agent-based system for supporting business-to-consumer electronic commerce (e-commerce) or mobile commerce (m-commerce) applications. To use the system, consumers first provide their buying requirements to a proxy/agent server through a Web browser or a wireless application protocol (WAP) terminal. Having obtained the requirements, mobile agents are generated to carry out tasks for the consumers including getting offers from merchants, evaluating offers, and even completing purchases. In the case of mobile commerce, consumers can generate a mobile agent to conduct a search and evaluation in the digital marketspace before making a purchase in the physical marketplace. To make it possible to choose an offer that best satisfies the consumer's requirement(s), we present a mathematical model for evaluating multiple decision factors. To test the basic functions of the mobile agent-based Internet commerce system (MAGICS), we have built a prototype system. To minimize the average cost of a product (including the cost of sending agents), we have also developed an analytical model that can determine how many agents should be sent to compare prices. Four different price distributions and some real price information are analyzed based on the model. The analysis provides valuable insights into the design of mobile agent-based shopping applications for m-commerce, in particular, and for e-commerce, in general.  相似文献   

15.
移动代理技术在Ad Hoc无线网络中的应用研究   总被引:1,自引:0,他引:1  
Ad Hoc无线网络是一组具有路由和转发功能的移动节点组成的一个多跳的临时性自治系统,是一种无中心的无线网络。现有的主动路由协议或者按需路由协议都不能很好地满足Ad Hoc网络的需要。介绍了Ad Hoc无线移动网络和移动代理技术。在分析了现有的2种路由协议后,提出了在按需路由协议中加入移动代理技术来增强Ad Hoc无线网络的性能。在这些结果的基础上,提出了移动代理通信协议。  相似文献   

16.
Random walk for self-stabilizing group communication in ad hoc networks   总被引:1,自引:0,他引:1  
We introduce a self-stabilizing group communication system for ad hoc networks. The system design is based on a mobile agent, collecting and distributing information, during a random walk. Three possible settings for modeling the location of the mobile nodes (processors) in the ad hoc network are presented: slow location change, complete random change, and neighbors with probability. The group membership algorithm is based on a mobile agent collecting and distributing information. The new techniques support group membership and multicast, and also support resource allocation.  相似文献   

17.
The discovery and management of desired network services present significant challenges for mobile networks. Based on the Service Location Protocol, this paper proposes an integrated service discovery architecture for vehicular ad hoc networks. The proposed approach divides the network into several logical zones. The zone structure is formed virtually based on position information. Each logical zone may have a zone directory agent to manage registered services from service providers. The proposed architecture considers both vehicle‐to‐infrastructure and vehicle‐to‐vehicle communication modes and introduces roadside directory agents and vehicle directory agents to reduce deployment costs. We also introduce a substitute query technique, cache mechanism, and backup mechanism to improve the request hit ratio and reduce the message overhead of the substitute query. Finally, we implement the proposed mechanisms in Network Simulator version 2, with simulation results showing that the proposed architecture can provide a high average data hit ratio and low message overhead. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

18.
该文分析了目前移动代理系统存在的主要安全问题及现有的解决方案,随后提出了一种基于混合加密的移动代理安全传输模型(HESTM)。该模型主要分成两部分: (1)利用混合加密算法加密移动代理;(2)利用TLS加密通信信道。仿真与性能分析表明,HESTM模型的确能有效地保护移动代理的传输安全,从而有效地提高了整个系统的安全性和稳健性。该箅法已成功地应用在作者开发的原型系统-基于移动代理的入侵检测系统中。  相似文献   

19.
Wireless mobile communications at the start of the 21st century   总被引:8,自引:0,他引:8  
At the start of the 21st century, the wireless mobile markets are witnessing unprecedented growth fueled by an information explosion and a technology revolution. In the radio frequency arena, the trend is to move from narrowband to wideband with a family of standards tailored to a variety of application needs. Many enabling technologies including wideband code-division multiple access, software-defined radio, intelligent antennas, and digital processing devices are greatly improving the spectral efficiency of third-generation systems. In the mobile network area, the trend is to move from traditional circuit-switched systems to packet-switched programmable networks that integrate both voice and packet services, and eventually evolve toward an all-IP network. Furthermore, accompanied by wireless mobile location technology, wireless mobile Internet is expected to revolutionize the services that can be provided to consumers in the right place and at the right time. Wireless mobile communications may not only complement the well established wireline network; it may also become a serious competitor in years to come. We review the history of the wireless mobile communications, examine the current progress in standards and technologies, and discuss possible trends for wireless mobile solutions  相似文献   

20.
Advances in technology have enabled a proliferation of mobile devices and a broad spectrum of novel and outbreaking solutions for new applications and services. The increasing demand for all time and everywhere services requires the network operators to integrate different kinds of wireless and cellular networks. To enable this integration, it is important that users can roam freely across networks. As different technologies are involved in the current infrastructure, the problem of vertical handover needs to be addressed. To cope with the problem of seamless connectivity, several solutions have been presented. But most of them either lack intelligence or are not adaptable for reducing the packet loss and delay involved in the handover procedure. An intelligent technique is needed in order to perform the service continuity in the heterogeneous environment. This paper presents a cooperative agent based approach for the vertical handover using a knowledge plane. We propose to introduce the agents in the mobile nodes and access points to collect the necessary information from the environment. Based on this information, agents take a handover decision. A selection function is also introduced in this work which helps in choosing a best network from the available ones for handover. Finally, the proposed approach is validated with the help of simulations.  相似文献   

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