Enhancing the Supply Chain Performance by Integrating Simulated and Physical Agents into Organizational Information Systems

As the business environment gets more complicated, organizations must be able to respond to the business changes and adjust themselves quickly to gain their competitive advantages. This study proposes an integrated agent system, called SPA, which coordinates simulated and physical agents to provide an efficient way for organizations to meet the challenges in managing supply chains. In the integrated framework, physical agents coordinate with inter-organizations\' physical agents to form workable business processes and detect the variations occurring in the outside world, whereas simulated agents model and analyze the what-if scenarios to support physical agents in making decisions. This study uses a supply chain that produces digital still cameras as an example to demonstrate how the SPA works. In this example, individual information systems of the involved companies equip with the SPA and the entire supply chain is modeled as a hierarchical object oriented Petri nets. The SPA here applies the modified AGNES data clustering technique and the moving average approach to help each firm generalize customers\' past demand patterns and forecast their future demands. The amplitude of forecasting errors caused by bullwhip effects is used as a metric to evaluate the degree that the SPA affects the supply chain performance. The experimental results show that the SPA benefits the entire supply chain by reducing the bullwhip effects and forecasting errors in a dynamic environment.Supply Chain Performance Enhancement; Bullwhip Effects; Simulated Agents; Physical Agents; Dynamic Customer Demand Pattern Discovery

Using mobility and exception handling to achieve mobile agents that survive server crash failures

Mobile agent technology, when designed and used effectively, can minimize bandwidth consumption and autonomously provide a snapshot of the current context of a distributed system. Protecting mobile agents from server crashes is a challenging issue, since developers normally have no control over remote servers. Server crash failures can leave replicas, instable storage, unavailable for an unknown time period. Furthermore, few systems have considered the need for using a fault tolerant protocol among a group of collaborating mobile agents. This thesis uses exception handling to protect mobile agents from server crash failures. An exception model is proposed for mobile agents and two exception handler designs are investigated. The first exists at the server that created the mobile agent and uses a timeout mechanism. The second, the mobile shadow scheme, migrates with the mobile agent and operates at the previous server visited by the mobile agent. A case study application has been developed to compare the performance of the two exception handler designs. Performance results demonstrate that although the second design is slower it offers the smaller trip time when handling a server crash. Furthermore, no modification of the server environment is necessary. This thesis shows that the mobile shadow exception handling scheme reduces complexity for a group of mobile agents to survive server crashes. The scheme deploys a replica that monitors the server occupied by the master, at each stage of the itinerary. The replica exists at the previous server visited in the itinerary. Consequently, each group member is a single fault tolerant entity with respect to server crash failures. Other schemes introduce greater complexity and performance overheads since, for each stage of the itinerary, a group of replicas is sent to servers that offer an equivalent service. In addition, future research is established for fault tolerance in groups of collaborating mobile agents

Heterogeneous networks using mobile-IP technology

Whenever a mobile user moves between networks a handover must occur. This basically means that a network-layer protocol must handle the moving of the mobile device. In a cellular phone a GSM/UMTS infrastructure performs horizontal handover and the user does not notices any call or ongoing session interruption while roaming. The handover procedure begins when the received signal strength identificator (RSSI) of a mobile device falls below a level, it discovers a neighbour access point with better quality of services (QoS) than its current access point. In heterogeneous wireless networks different portions of RF spectrum are used and is difficult or impossible for a mobile node to concurrently maintain its connectivity without signal interruptions. Thus, the different network environments must be integrated and support a common platform to achieve seamless handover. The seamless or vertical handover's target is to maintain the mobile user's IP address independently of user's location or of the physical parameters the current network is using. A mechanism that keeps a mobile device to an ongoing connection by maintaining its home-location IP address is the Mobile-IP protocol which operates at the network-layer of the Open System Interconnection (OSI) model. In this M.Sc. thesis we perform heterogeneous network scenarios with the Mobile-IP technology. Moreover, we have built the system practically and assist the applicability of such heterogeneous wireless networks through real-side measurements. We used Linux operating system (Ubuntu & Debian) between different network technologies, made at the National Center for Scientific Research (NCSR) ''Demokritos'' institute, in Greece. The required applications for the Mobile-IP and 3G technologies were implemented and configured in a platform of fixed and mobile devices at Demokrito's departmental laboratory. The idea of using the Mobile-IP protocol was to gather information about time differences that occurred in handover delay between different networks.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

The urban real-time traffic control (URTC) system : a study of designing the controller and its simulation

The growth of the number of automobiles on the roads in China has put higher demands on the traffic control system that needs to efficiently reduce the level of congestion occurrence, which increases travel delay, fuel consumption, and air pollution. The traffic control system, urban real-time traffic control system based on multi-agent (MA-URTC) is presented in this thesis. According to the present situation and the traffic's future development in China, the researches on intelligent traffic control strategy and simulation based on agent lays a foundation for the realization of the system. The thesis is organized as follows: The first part focuses on the intersection' real-time signal control strategy. It contains the limitations of current traffic control systems, application of artificial intelligence in the research, how to bring the dynamic traffic flow forecast into effect by combining the neural network with the genetic arithmetic, and traffic signal real-time control strategy based on fuzzy control. The author uses sorne simple simulation results to testify its superiority. We adopt the latest agent technology in designing the logical structure of the MA-URTC system. By exchanging traffic flows information among the relative agents, MA-URTC provides a new concept in urban traffic control. With a global coordination and cooperation on autonomy-based view of the traffic in cities, MA-URTC anticipates the congestion and control traffic flows. It is designed to support the real-time dynamic selection of intelligent traffic control strategy and the real-time communication requirements, together with a sufficient level of fault-tolerance. Due to the complexity and levity of urban traffic, none strategy can be universally applicable. The agent can independently choose the best scheme according to the real-time situation. To develop an advanced traffic simulation system it can be helpful for us to find the best scheme and the best switch-point of different schemes. Thus we can better deal with the different real-time traffic situations. The second part discusses the architecture and function of the intelligent traffic control simulation based on agent. Meanwhile the author discusses the design model of the vehicle-agent, road agent in traffic network and the intersection-agent so that we can better simulate the real-time environment. The vehicle-agent carries out the intelligent simulation based on the characteristics of the drivers in the actual traffic condition to avoid the disadvantage of the traditional traffic simulation system, simple-functioned algorithm of the vehicles model and unfeasible forecasting hypothesis. It improves the practicability of the whole simulation system greatly. The road agent's significance lies in its guidance of the traffic participants. It avoids the urban traffic control that depends on only the traffic signal control at intersection. It gives the traffic participants the most comfortable and direct guidance in traveling. It can also make a real-time and dynamic adjustment on the urban traffic flow, thus greatly lighten the pressure of signal control in intersection area. To sorne extent, the road agent is equal to the pre-caution mechanism. In the future, the construction of urban roads tends to be more intelligent. Therefore, the research on road agent is very important. All kinds of agents in MA-URTC are interconnected through a computer network. In the end, the author discusses the direction of future research. As the whole system is a multi-agent system, the intersection, the road and the vehicle belongs to multi-agent system respectively. So the emphasis should be put on the structure design and communication of all kinds of traffic agents in the system. Meanwhile, as an open and flexible real-time traffic control system, it is also concerned with how to collaborate with other related systems effectively, how to conform the resources and how to make the traffic participants anywhere throughout the city be in the best traffic guidance at all times and places. To actualize the genuine ITS will be our final goal. \ud ______________________________________________________________________________ \ud MOTS-CLÉS DE L’AUTEUR : Artificial Intelligence, Computer simulation, Fuzzy control, Genetic Algorithm, Intelligent traffic control, ITS, Multi-agent, Neural Network, Real-time

Proceedings of the 2nd International Workshop on Security in Mobile Multiagent Systems

This report contains the Proceedings of the Second Workshop on Security on Security of Mobile Multiagent Systems (SEMAS2002). The Workshop was held in Montreal, Canada as a satellite event to the 5th International Conference on Autonomous Agents in 2001. The far reaching influence of the Internet has resulted in an increased interest in agent technologies, which are poised to play a key role in the implementation of successful Internet and WWW-based applications in the future. While there is still considerable hype concerning agent technologies, there is also an increasing awareness of the problems involved. In particular, that these applications will not be successful unless security issues can be adequately handled. Although there is a large body of work on cryptographic techniques that provide basic building-blocks to solve specific security problems, relatively little work has been done in investigating security in the multiagent system context. Related problems are secure communication between agents, implementation of trust models/authentication procedures or even reflections of agents on security mechanisms. The introduction of mobile software agents significantly increases the risks involved in Internet and WWW-based applications. For example, if we allow agents to enter our hosts or private networks, we must offer the agents a platform so that they can execute correctly but at the same time ensure that they will not have deleterious effects on our hosts or any other agents / processes in our network. If we send out mobile agents, we should also be able to provide guarantees about specific aspects of their behaviour, i.e., we are not only interested in whether the agents carry out-out their intended task correctly. They must defend themselves against attacks initiated by other agents, and survive in potentially malicious environments. Agent technologies can also be used to support network security. For example in the context of intrusion detection, intelligent guardian agents may be used to analyse the behaviour of agents on a firewall or intelligent monitoring agents can be used to analyse the behaviour of agents migrating through a network. Part of the inspiration for such multi-agent systems comes from primitive animal behaviour, such as that of guardian ants protecting their hill or from biological immune systems

A reinforcement learning algorithm for optimalVirtual network functions allocations among 5G edge computing centers

The fifth generation (5G) mobile networks are enabling operators and stakeholders to enhance and innovate new services in response to an increasing market demand. 5G architecture provides scalability and flexibility for adapting its infrastructure to a customizable communication system by means of Cloudification. Softwarization and virtualization are key terms for upcoming industries that will require ultra-low latency, only possible if the infrastructure equipment that traditionally was centralized in the communication network core is physically moved closer to the user, at the network edge. The main objective of this master thesis was to implement a Reinforcement Learning algorithm (Q-Learning Temporal Difference) aimed at next generation networks to optimally allocate Virtualized Network Functions (VNF) to 5G network Edge Computing (EC) centers. In order to evaluate the algorithm performance and compare it, two more algorithms have been developed to achieve a solution under the same network circumstances. The first one, Best Fit, was inspired by a classical network load balancing algorithm (Weighted Round Robin), whereas the second, MDP, was approached through dynamic programming (Policy Iteration), having posed the network dynamics as a finite Markov Decision Process. The several tests that have been carried out indicate that Q-Learning performs better than the Best Fit and almost as close as the MDP. It shows that the Q-Learning algorithm is able to allocate optimally the incoming VNF demands when EC centers' available resources are somehow restricted

Server selection for mobile agent migration

The purpose of this thesis is to develop, test, and simulate an algorithm that mobile software agents can use to select a server to which the agents can migrate. Software agents are autonomous software entities that perform tasks on behalf of other agents or humans, and that have some degree of intelligence. In particular, a mobile software agent is capable of migrating from one computer system (agent server) to another during the course of performing its tasks. Most current implementations of mobile software agents (simply referred to as agents) have simple forms of server selection. The algorithm discussed in this thesis proposes new ideas for dealing with the server selection process. The algorithm proposed in this thesis is intended to provide a good basis from which further work can be continued in the area of agent server selection. This algorithm was demonstrated to work as expected under a set of boundary conditions of purely abstract computer resources. Then the algorithm was used in a simulation of a print job scheduler for a cluster of printers. Some of the concepts that this algorithm uses are resource importance factors, needed and wanted resources, risk factors, server resource evaluations, and server resource availability

Net.Sense

Net.sense will server as a proof-of-concept of a new type of network management system, using biological models and statistical principles to address scalability, predictability, and reliability issues associated with managing the highly complex computer systems that we as a society have come to depend on

Simulating social relations in multi-agent systems

Open distributed systems are comprised of a large number of heterogeneous nodes with disparate requirements and objectives, a number of which may not conform to the system specification. This thesis argues that activity in such systems can be regulated by using distributed mechanisms inspired by social science theories regarding similarity /kinship, trust, reputation, recommendation and economics. This makes it possible to create scalable and robust agent societies which can adapt to overcome structural impediments and provide inherent defence against malicious and incompetent action, without detriment to system functionality and performance. In particular this thesis describes: • an agent based simulation and animation platform (PreSage), which offers the agent developer and society designer a suite of powerful tools for creating, simulating and visualising agent societies from both a local and global perspective. • a social information dissemination system (SID) based on principles of self organisation which personalises recommendation and directs information dissemination. • a computational socio-cognitive and economic framework (CScEF) which integrates and extends socio-cognitive theories of trust, reputation and recommendation with basic economic theory. • results from two simulation studies investigating the performance of SID and the CScEF. The results show the production of a generic, reusable and scalable platform for developing and animating agent societies, and its contribution to the community as an open source tool. Secondly specific results, regarding the application of SID and CScEF, show that revealing outcomes of using socio-technical mechanisms to condition agent interactions can be demonstrated and identified by using Presage.Open Acces