Dynamic load distribution with hop-by-hop forwarding based on max-min one-way delay

Load balancing can effectively improve network performance and scalability,but it may cause packet disorder,so worsening the performance.Additionally,without MPLS to establish the desired end-to-end paths,hop-by-hop routing load balancing is more difficult to achieve than the source routing;however,it can significantly improve network performance.In this paper,we propose a load balancing scheme with hop-by-hop routing,by using the burstiness features of flows to make sure that the packets of the same flow arrive at the receiving end in order.Simulation results show that our algorithm can adapt to the dynamic changes of the end-to-end delay and the routing vector,and also can achieve fine-gained load balancing.     

Mobile agent-enabled framework for structuring and building distributed systems on the internet

Mobile agent has shown its promise as a powerful means to complement and enhance existing technology in various application areas. In particular, existing work has demonstrated that MA can simplify the development and improve the performance of certain classes of distributed applications, especially for those running on a wide-area, heterogeneous, and dynamic networking environment like the Internet. In our previous work, we extended the application of MA to the design of distributed control functions, which require the maintenance of logical relationship among and/or coordination of proc- essing entities in a distributed system. A novel framework is presented for structuring and building distributed systems, which use cooperating mobile agents as an aid to carry out coordination and cooperation tasks in distributed systems. The framework has been used for designing various distributed control functions such as load balancing and mutual ex- clusion in our previous work. In this paper, we use the framework to propose a novel ap- proach to detecting deadlocks in distributed system by using mobile agents, which dem- onstrates the advantage of being adaptive and flexible of mobile agents. We first describe the MAEDD (Mobile Agent Enabled Deadlock Detection) scheme, in which mobile agents are dispatched to collect and analyze deadlock information distributed across the network sites and, based on the analysis, to detect and resolve deadlocks. Then the design of an adaptive hybrid algorithm derived from the framework is presented. The algorithm can dynamically adapt itself to the changes in system state by using different deadlock detec- tion strategies. The performance of the proposed algorithm has been evaluated using simulations. The results show that the algorithm can outperform existing algorithms that use a fixed deadlock detection strategy.     

A Load Balancing Algorithm in OpenFIow Networks

The goal of load balancing algorithm in OpenFlow networks is to combine the load balancing technology with the Open lqow technology, so that load balancing can adapt to the characteristics of the OpenFlow networks.The study of this paper focused on load balancing in OpenFlow networks, proposed a new load balancing algorithm.The algorithm considered the status of servers and network comprehensively, and provided the metrics for them.To distribute the network traffic to the servers and links reasonably, the goal of load balancing is reached.     

Fault tolerant algorithm based on dynamic and active load balancing for redundant services

A new Some-Read-Any-Write (SRAW) fault tolerant algorithm for redundant services is presented that allows a system to adjust failures dynamically in order to keep the availability and improve the performance.SRAW is based upon dynamic and active load balancing. By introducing dynamic and active load balancings cheme into redundant services, not only the processing speed of requests can be greatly improved, but also the load balancing can be simply and efficiently achieved. Integrated with consistency protocol in this paper, SRAW can also be applied to state services. The performance of SRAW algorithm is also analyzed, and comparisons with other fault tolerant algorithms, especially with RAWA, indicate that SRAW efficiently improves the performance of redundant services with guaranteeing system availability.     

A novel algorithm for routing and wavelength assignment considering the load balancing

For the problem of routing and wavelength assignment in Wavelength Division Multiplexing （WDM） optical transport network, an algorithm based on the state of links is proposed, which is named Tradeoff_LSDRAW, and which can select a path with the higher state level between a pair of nodes in a network. Finally, by an example network, we show that the algorithm has the stronger capability of selecting a better path between a pair of nodes, and can achieve the load balancing and reduce the congestion probability in WDM optical transport networks.     

Evaluation of Program Code Caching for Mobile Agent Migrations

Mobile agents are able to migrate among machines to achieve their tasks. This feature is attractive to design, implement, and maintain distributed systems because we can implement both client-side and server-side programming in one mobile agent. However, it involves the increase of data traffic for mobile agent migrations. In this paper, we propose program code caching to reduce the data traffic caused by mobile agent migrations. A mobile agent consists of many program codes that define a task executed in each machine they migrate; thus, the mobile agent migration involves the transfer of their program codes. Therefore, our method reduces the number of the transfer of program codes by using program code cache. We have implemented our method on a mobile agent framework called Maglog and conducted experiments on a meeting scheduling system.     

基于JavaCard的移动代理系统安全性研究

With wide and increasing range applications of mobile agent technology, the security problem has gotten more and more focus. This paper discusses the security problems that the mobile agent system faces with at presentand the existing protesting schemes for it. Then a solving method based on JavaCard is proposed to protect mobile a-gents. And a feasible solving method is also provided to solve the security problems of JavaCard itself.     

Strategy and Simulation of Adaptive RID for Distributed Dynamic Load Balancing in Parallel Systems

Dynamic load balancing schemes are significant for efficiently executing nonuniform problems in highly parallel multicomputer systems.The objective is to minimize the total exectuion time of single applications.This paper has proposed an ARID strategy for distributed dynamic load balancing.Its principle and control protocol are described,and te communication overhead,the effect on system stability and the performance efficiency are analyzed.Finally,simulation experiments are carried out to compare the adaptive strategy with other dynamic load balancing schemes.     

A unified algorithm for mobility load balancing in 3GPP LTE multi-cell networks

3GPP long term evolution (LTE) is a promising candidate for the next-generation wireless network, which is expected to achieve high spectrum efficiency by using advanced physical layer techniques and flat network structures. However, the LTE network still faces the problem of load imbalance as in GSM/WCDMA networks, and this may cause significant deterioration of system performance. To deal with this problem, mobility load balancing (MLB) has been proposed as an important use case in 3GPP self-organizing network (SON), in which the serving cell of a user can be selected to achieve load balancing rather than act as the cell with the maximum received power. Furthermore, the LTE network aims to serve users with different quality-of-service (QoS) requirements, and the network-wide objective function for load balancing is distinct for different kinds of users. Thus, in this paper, a unified algorithm is proposed for MLB in the LTE network. The load balancing problem is first formulated as an optimization problem with the optimizing variables being cell-user connections. Then the complexity and overhead of the optimal solution is analyzed and a practical and distributed algorithm is given. After that, the proposed algorithm is evaluated for users with different kinds of QoS requirements, i.e., guaranteed bit rate (GBR) users with the objective function of load balance index and non-GBR (nGBR) users with the objective function of total utility, respectively. Simulation results show that the proposed algorithm leads to significantly balanced load distribution for GBR users to decrease the new call blocking rate, and for nGBR users to improve the cell-edge throughput at the cost of only slight deterioration of total throughput.     

基于主从样式的移动代理安全模型的研究与实现

In the ages of current network technology, as a new technology, the emergence of mobile agent shows us a wider and wider application prospect in the fields of network technology, such as Network Management,Intelligence Information Retrieval and Electronic Commence and so on. The security is the essence of mobile agent technology. In this paper we analyze the security issues and survey some representative approaches to solve the problem in mobile agent systems. We focus on the issues about the agent's security and propose a master-slave designpattern based security model for mobile agent called SMAP(Secure Mobile Agent Platform). In the end we give anapplication example to show how to use these.     

Cost-Sensitive and Load-Balancing Gateway Placement in Wireless Mesh Networks with QoS Constraints

In wireless mesh networks(WMNs),gateway placement is the key to network performance,QoS and construction cost.This paper focuses on the optimization of the cost and load balance in the gateway placement strategy,ensuring the QoS requirements.Firstly,we define a metric for load balance on the gateways,and address the minimum cost and load balancing gateway placement problem.Secondly,we propose two algorithms for gateway placement.One is a heuristic algorithm,which is sensitive to the cost,selects the gate...     

移动Agent系统通信失效问题研究

The Mobile Agent is thought to be the popular computing model for the next generation's distributed sys-tem. The mobile agent has the following key features: autonomy, collaboration, security and especially mobility. Agood communication model for mobile agents cooperation is also necessary. In this article, after describing the maincommunication mechanisms, we analyze the methods to solve Agent Tracking and Communication Failure and make classification. We also propose a reliable and efficient mechanism named MEFS which uses Detecting methods and then analyze its performance by giving the experimental data at the end.     

Research on the Activity Frame Work of Using Visual Thinking Tools

The development of high order thinking has been considered as a national priority of learning. By using three iteration action research in six elementary schools in Guangzhou, China for about 1 year and a half, we found that visual thinking tools can improve students＇ high order thinking ability and change the traditional teaching method. By using this activity frame work, the teachers can better understand what are the students thinking about and the students can use the thinking tools to help themselves solve complex problems and discuss with other people. The reason we do this research is to improve the high-order thinking ability of primary student. In this paper, we summarize an activity frame work of using visual thinking tools to improve students thinking ability. And the frame work can be divided into three stages： preparatory stage, implementation stage and assessment stage. And different stage has different activity. Though this activity frame work is not perfect enough, we will improve it in our future study.     

A Dynamic Load Balancing Mechanism for Distributed Systems

It is desirable in a distributed system to have the system load balanced evenly among the nodes so that the mean job response time is minimized.In this paper,we present a dynamic load balancing mechanism(DLB).It adopts a cntralized approach and is network topology independent.The DLB mechanism employs a set of threscholds which are automatically adjusted as the system load changes.It also provides a simple mechanism for the system to switch between periodic and instantaneous load balancing policies with ease.The performance of the proposed algorithm is evaluated by intensive simulations for various parameters.Te simulation results show that the mean job response time in a system implementing DLB algorithm is significantly lower than the same system without load balancings.Furthermore,compared with a previously proposed algorithm,DLB algorithm demonstrates improved performance,especially when the system is heavily loaded and the load is unevenly distributed.     

Coordination of multiple mobile robots with limited communication range in pursuit of single mobile target in cluttered environment

This paper addresses the problem of coordinating multiple mobile robots in searching for and capturing a mobile target, with the aim of reducing the capture time. Compared with the previous algorithms, we assume that the target can be detected by any robot and captured successfully by two or more robots. In this paper, we assume that each robot has a limited communication range. We maintain the robots within a mobile network to guarantee the successful capture. In addition, the motion of the target is modeled and incorporated into directing the motion of the robots to reduce the capture time. A coordination algorithm considering both aspects is proposed. This algorithm can greatly reduce the expected time of capturing the mobile target. Finally, we validate the algorithm by the simulations and experiments.     

Bandwidth Reservation Using Velocity and Handoff Statistics for Cellular Networks

The percentages of blocking and forced termination rates as parameters representing quality of services （QoS） requirements are presented. The relation between the connection statistics of mobile users in a cell and the handoff number and new call number in next duration in each cell is explored. Based on the relation, statistic reservation tactics are raised. The amount of bandwidth for new calls and handoffs of each cell in next period is determined by using the strategy. Using this method can guarantee the communication system suits mobile connection request dynamic. The QoS parameters： forced termination rate and blocking rate can be maintained steadily though they may change with the offered load, Some numerical experiments demonstrate this is a practical method with affordable overhead.     

Secure Web Transaction with Anonymous Mobile Agent over Internet

A major problem of mobile agents is their apparent inability to authenticate transactions in hostile environments. In this paper, a new secure anonymous mobile agent scheme is proposed for the prevention of agent tempering without compromising the mobility or autonomy of the agent. In the scheme, a mobile agent can produce valid signature on website's bid (it means to transact a contact with the web site) on behalf of its customer, without revealing the customer's real private key. In addition, the anonymity of the customer is also achieved when its agent transacts with the websites. Furthermore, the customer who issues a malicious agent or denies the transaction can be identified and detected by Agent Management Center (AMC). Therefore, the scheme is practical in the future electronic commerce over Internet.     

MADIDS：一种基于移动代理的新型分布式入侵检测系统

When traditional Intrusion Detection System(IDS)is used to detect and analyze the great flow data transfer in high-speed network,it usually causes the computation bottleneck.This paper presents a new Mobile Agent Distributed IDS(MADIDS) system based on the mobile agents.This system is specifically designed to process the great flow data transfer in high-speed network.In MADIDS,the agents that are set at each node process the data transfer by distributed computation architecture.Meanwhile by using the reconfiguration quality of the mobile agents,the load balance of distributed computation can be dynamically implemented to gain the high-performance computing ability.This ability makes the detecting and analyzing of high-speed network possible.MADIDS can effectively solve the detection and analysis performance bottleneck caused by the great flow data transfer in high-speed network.It enhances the performance of IDS in high-speed network.In this paper,we construct the infrastructure and theoretical model of MADIDS,and the deficiencies of MADIDS and future research work are also indicated.     

Secure web transaction with anonymous mobile agent over internet

A major problem of mobile agents is their apparent mability to authenticate transactions in hostile environments,In this paper,a new secure anonymous mobile agent scheme is proposed for the prevention of agent tempering without compromising the mobility or autonomy of the agent.in the scheme,a mobile agent can produce valid signature on website‘s bid(it means to transact a contact with the web site)on behalf of its customer ,without-revealing the customer‘s real private key.In addition,the anonymity of the customer is also achieved when its agent tansacts with the websites.Furthermore,the customer who issues a malicious agent or denies the transaction can be identified and detected by Agent Management Center(AMC).Thererfore,the scheme is practical in the future elecronic commerce over Internet.     

基于规则的分层负载平衡调度模型

On a massively parallel and distributed system and a network of workstations system, it is a critical problem to increase the utilization efficiency of resources and the answer speed of tasks by using effective load balancing scheduling strategy. This paper analyzes the scheduling strategy of dynamic load balancing and static load balancing,and then proposes a hierarchical load balancing scheduling model based on rules. Finally,making somecomparisons with Other scheduling models.