578 research outputs found

    Distributed, decentralised and compensational mechanisms for platoon formation

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    Verkehrsprobleme nehmen mit der weltweiten Urbanisierung und der Zunahme der Anzahl der Fahrzeuge pro Kopf zu. Platoons, eine Formation von eng hintereinander fahrenden Fahrzeugen, stellen sich als mögliche Lösung dar, da bestehende Forschungen darauf hinweisen, dass sie zu einer besseren Straßenauslastung beitragen, den Kraftstoffverbrauch und die Emissionen reduzieren und EngpĂ€sse schneller entlasten können. Rund um das Thema Platooning gibt es viele Aspekte zu erforschen: Sicherheit, StabilitĂ€t, Kommunikation, Steuerung und Betrieb, die allesamt notwendig sind, um den Einsatz von Platooning im Alltagsverkehr nĂ€her zu bringen. WĂ€hrend in allen genannten Bereichen bereits umfangreiche Forschungen durchgefĂŒhrt wurden, gibt es bisher nur wenige Arbeiten, die sich mit der logischen Gruppierung von Fahrzeugen in Platoons beschĂ€ftigen. Daher befasst sich diese Arbeit mit dem noch wenig erforschten Problem der Platoonbildung, wobei sich die vorhandenen Beispiele mit auf Autobahnen fahrenden Lastkraftwagen beschĂ€ftigen. Diese FĂ€lle befinden sich auf der strategischen und taktischen Ebene der Planung, da sie von einem großen Zeithorizont profitieren und die Gruppierung entsprechend optimiert werden kann. Die hier vorgestellten AnsĂ€tze befinden sich hingegen auf der operativen Ebene, indem Fahrzeuge aufgrund der verteilten und dezentralen Natur dieser AnsĂ€tze spontan und organisch gruppiert und gesteuert werden. Dadurch entstehen sogenannte opportunistische Platoons, die aufgrund ihrer FlexibilitĂ€t eine vielversprechende Voraussetzung fĂŒr alle Netzwerkarte bieten könnten. Insofern werden in dieser Arbeit zwei neuartige Algorithmen zur Bildung von Platoons vorgestellt: ein verteilter Ansatz, der von klassischen Routing-Problemen abgeleitet wurde, und ein ergĂ€nzender dezentraler kompensatorischer Ansatz. Letzteres nutzt automatisierte Verhandlungen, um es den Fahrzeugen zu erleichtern, sich auf der Basis eines monetĂ€ren Austausches in einem Platoon zu organisieren. In Anbetracht der Tatsache, dass alle Verkehrsteilnehmer ĂŒber eine Reihe von PrĂ€ferenzen, EinschrĂ€nkungen und Zielen verfĂŒgen, muss das vorgeschlagene System sicherstellen, dass jede angebotene Lösung fĂŒr die einzelnen Fahrzeuge akzeptabel und vorteilhaft ist und den möglichen Aufwand, die Kosten und die Opfer ĂŒberwiegt. Dies wird erreicht, indem den Platooning-Fahrzeugen eine Form von Anreiz geboten wird, im Sinne von entweder Kostensenkung oder Ampelpriorisierung. Um die vorgeschlagenen Algorithmen zu testen, wurde eine Verkehrssimulation unter Verwendung realer Netzwerke mit realistischer Verkehrsnachfrage entwickelt. Die Verkehrsteilnehmer wurden in Agenten umgewandelt und mit der notwendigen FunktionalitĂ€t ausgestattet, um Platoons zu bilden und innerhalb dieser zu operieren. Die Anwendbarkeit und Eignung beider AnsĂ€tze wurde zusammen mit verschiedenen anderen Aspekten untersucht, die den Betrieb von Platoons betreffen, wie GrĂ¶ĂŸe, Verkehrszustand, Netzwerkpositionierung und Anreizmethoden. Die Ergebnisse zeigen, dass die vorgeschlagenen Mechanismen die Bildung von spontanen Platoons ermöglichen. DarĂŒber hinaus profitierten die teilnehmenden Fahrzeuge mit dem auf verteilter Optimierung basierenden Ansatz und unter Verwendung kostensenkender Anreize unabhĂ€ngig von der Platoon-GrĂ¶ĂŸe, dem Verkehrszustand und der Positionierung, mit Nutzenverbesserungen von 20% bis ĂŒber 50% im Vergleich zur untersuchten Baseline. Bei zeitbasierten Anreizen waren die Ergebnisse uneinheitlich, wobei sich der Nutzen einiger Fahrzeuge verbesserte, bei einigen keine VerĂ€nderung eintrat und bei anderen eine Verschlechterung zu verzeichnen war. Daher wird die Verwendung solcher Anreize aufgrund ihrer mangelnden Pareto-Effizienz nicht empfohlen. Der kompensatorische und vollstĂ€ndig dezentralisierte Ansatz weißt einige Vorteile auf, aber die daraus resultierende Verbesserung war insgesamt vernachlĂ€ssigbar. Die vorgestellten Mechanismen stellen einen neuartigen Ansatz zur Bildung von Platoons dar und geben einen aussagekrĂ€ftigen Einblick in die Mechanik und Anwendbarkeit von Platoons. Dies schafft die Voraussetzungen fĂŒr zukĂŒnftige Erweiterungen in der Planung, Konzeption und Implementierung effektiverer Infrastrukturen und Verkehrssysteme.Traffic problems have been on the rise corresponding with the increase in worldwide urbanisation and the number of vehicles per capita. Platoons, which are a formation of vehicles travelling close together, present themselves as a possible solution, as existing research indicates that they can contribute to better road usage, reduce fuel consumption and emissions and decongest bottlenecks faster. There are many aspects to be explored pertaining to the topic of platooning: safety, stability, communication, controllers and operations, all of which are necessary to bring platoons closer to use in everyday traffic. While extensive research has already made substantial strides in all the aforementioned fields, there is so far little work on the logical grouping of vehicles in platoons. Therefore, this work addresses the platoon formation problem, which has not been heavily researched, with existing examples being focused on large, freight vehicles travelling on highways. These cases find themselves on the strategic and tactical level of planning since they benefit from a large time horizon and the grouping can be optimised accordingly. The approaches presented here, however, are on the operational level, grouping and routing vehicles spontaneously and organically thanks to their distributed and decentralised nature. This creates so-called opportunistic platoons which could provide a promising premise for all networks given their flexibility. To this extent, this thesis presents two novel platoon forming algorithms: a distributed approach derived from classical routing problems, and a supplementary decentralised compensational approach. The latter uses automated negotiation to facilitate vehicles organising themselves in a platoon based on monetary exchanges. Considering that all traffic participants have a set of preferences, limitations and goals, the proposed system must ensure that any solution provided is acceptable and beneficial for the individual vehicles, outweighing any potential effort, cost and sacrifices. This is achieved by offering platooning vehicles some form of incentivisation, either cost reductions or traffic light prioritisation. To test the proposed algorithms, a traffic simulation was developed using real networks with realistic traffic demand. The traffic participants were transformed into agents and given the necessary functionality to build platoons and operate within them. The applicability and suitability of both approaches were investigated along with several other aspects pertaining to platoon operations such as size, traffic state, network positioning and incentivisation methods. The results indicate that the mechanisms proposed allow for spontaneous platoons to be created. Moreover, with the distributed optimisation-based approach and using cost-reducing incentives, participating vehicles benefited regardless of the platoon size, traffic state and positioning, with utility improvements ranging from 20% to over 50% compared to the studied baseline. For time-based incentives the results were mixed, with the utility of some vehicles improving, some seeing no change and for others, deteriorating. Therefore, the usage of such incentives would not be recommended due to their lack of Pareto-efficiency. The compensational and completely decentralised approach shows some benefits, but the resulting improvement was overall negligible. The presented mechanisms are a novel approach to platoon formation and provide meaningful insight into the mechanics and applicability of platoons. This sets the stage for future expansions into planning, designing and implementing more effective infrastructures and traffic systems

    Contributions to Service Level Agreement (SLA), Negotiation and Monitoring in Cloud Computing

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    Cloud computing is a dynamic field of research, as the latest advances in the cloud computing applications have led to development of a plethora of cloud services in the areas of software, hardware, storage, internet of things connected to the cloud, and 5G supported by the cloud networks. Due to ever increasing developments and the subsequent emergence of a wide range of cloud services, a cloud market was created with cloud providers and customers seeking to buy the cloud services. With the expansion of the cloud market and the presence of a virtual environment in which cloud services are provided and managed, the face to-face meetings between customers and cloud providers is almost impossible, and the negotiation over the cloud services using the state-of-the-art autonomous negotiation agents has been theorized and researched by several researchers in the field of cloud computing, however, the solutions offered by literature are less applicable in the real-time cloud market with the evolving nature of services and customers’ requirements. Therefore, this study aimed to develop the solutions addressing issues in relation to negotiation of cloud services leading to the development of a service-level agreement (SLA), and monitoring of the terms and conditions specified in the SLA. We proposed the autonomous service-level framework supported by the autonomous agents for negotiating over the cloud services on behalf of the cloud providers and customers. The proposed framework contained gathering, filtering, negotiation and SLA monitoring functions, which enhanced its applicability in the real-time cloud market environment. Gathering and filtering stages facilitated the effectiveness of the negotiation phase based on the requirements of customers and cloud services available in the cloud market. The negotiation phase was executed by the selection of autonomous agents, leading to the creation of an SLA with metrics agreed upon between the cloud provider and the customer. Autonomous agents improved the efficiency of negotiation over multiple issues by creating the SLA within a short time and benefiting both parties involved in the negation phase. Rubinstein’s Alternating Offers Protocol was found to be effective in drafting the automated SLA solutions in the challenging environment of the cloud market. We also aimed to apply various autonomous agents to build the new algorithms which can be used to create novel negotiation strategies for addressing the issues in SLAs in cloud computing. The monitoring approach based on the CloudSim tool was found to be an effective strategy for detecting violations against the SLA, which can be an important contribution to building effective monitoring solutions for improving the quality of services in the cloud market

    Automated Service Negotiation Between Autonomous Computational Agents

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    PhDMulti-agent systems are a new computational approach for solving real world, dynamic and open system problems. Problems are conceptualized as a collection of decentralised autonomous agents that collaborate to reach the overall solution. Because of the agents autonomy, their limited rationality, and the distributed nature of most real world problems, the key issue in multi-agent system research is how to model interactions between agents. Negotiation models have emerged as suitable candidates to solve this interaction problem due to their decentralised nature, emphasis on mutual selection of an action, and the prevalence of negotiation in real social systems. The central problem addressed in this thesis is the design and engineering of a negotiation model for autonomous agents for sharing tasks and/or resources. To solve this problem a negotiation protocol and a set of deliberation mechanisms are presented which together coordinate the actions of a multiple agent system. In more detail, the negotiation protocol constrains the action selection problem solving of the agents through the use of normative rules of interaction. These rules temporally order, according to the agents' roles, communication utterances by specifying both who can say what, as well as when. Specifically, the presented protocol is a repeated, sequential model where offers are iteratively exchanged. Under this protocol, agents are assumed to be fully committed to their utterances and utterances are private between the two agents. The protocol is distributed, symmetric, supports bi and/or multi-agent negotiation as well as distributive and integrative negotiation. In addition to coordinating the agent interactions through normative rules, a set of mechanisms are presented that coordinate the deliberation process of the agents during the ongoing negotiation. Whereas the protocol normatively describes the orderings of actions, the mechanisms describe the possible set of agent strategies in using the protocol. These strategies are captured by a negotiation architecture that is composed of responsive and deliberative decision mechanisms. Decision making with the former mechanism is based on a linear combination of simple functions called tactics, which manipulate the utility of deals. The latter mechanisms are subdivided into trade-off and issue manipulation mechanisms. The trade-off mechanism generates offers that manipulate the value, rather than the overall utility, of the offer. The issue manipulation mechanism aims to increase the likelihood of an agreement by adding and removing issues into the negotiation set. When taken together, these mechanisms represent a continuum of possible decision making capabilities: ranging from behaviours that exhibit greater awareness of environmental resources and less to solution quality, to behaviours that attempt to acquire a given solution quality independently of the resource consumption. The protocol and mechanisms are empirically evaluated and have been applied to real world task distribution problems in the domains of business process management and telecommunication management. The main contribution and novelty of this research are: i) a domain independent computational model of negotiation that agents can use to support a wide variety of decision making strategies, ii) an empirical evaluation of the negotiation model for a given agent architecture in a number of different negotiation environments, and iii) the application of the developed model to a number of target domains. An increased strategy set is needed because the developed protocol is less restrictive and less constrained than the traditional ones, thus supporting development of strategic interaction models that belong more to open systems. Furthermore, because of the combination of the large number of environmental possibilities and the size of the set of possible strategies, the model has been empirically investigated to evaluate the success of strategies in different environments. These experiments have facilitated the development of general guidelines that can be used by designers interested in developing strategic negotiating agents. The developed model is grounded from the requirement considerations from both the business process management and telecommunication application domains. It has also been successfully applied to five other real world scenarios

    Service management for multi-domain Active Networks

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    The Internet is an example of a multi-agent system. In our context, an agent is synonymous with network operators, Internet service providers (ISPs) and content providers. ISPs mutually interact for connectivity's sake, but the fact remains that two peering agents are inevitably self-interested. Egoistic behaviour manifests itself in two ways. Firstly, the ISPs are able to act in an environment where different ISPs would have different spheres of influence, in the sense that they will have control and management responsibilities over different parts of the environment. On the other hand, contention occurs when an ISP intends to sell resources to another, which gives rise to at least two of its customers sharing (hence contending for) a common transport medium. The multi-agent interaction was analysed by simulating a game theoretic approach and the alignment of dominant strategies adopted by agents with evolving traits were abstracted. In particular, the contention for network resources is arbitrated such that a self-policing environment may emerge from a congested bottleneck. Over the past 5 years, larger ISPs have simply peddled as fast as they could to meet the growing demand for bandwidth by throwing bandwidth at congestion problems. Today, the dire financial positions of Worldcom and Global Crossing illustrate, to a certain degree, the fallacies of over-provisioning network resources. The proposed framework in this thesis enables subscribers of an ISP to monitor and police each other's traffic in order to establish a well-behaved norm in utilising limited resources. This framework can be expanded to other inter-domain bottlenecks within the Internet. One of the main objectives of this thesis is also to investigate the impact on multi-domain service management in the future Internet, where active nodes could potentially be located amongst traditional passive routers. The advent of Active Networking technology necessitates node-level computational resource allocations, in addition to prevailing resource reservation approaches for communication bandwidth. Our motivation is to ensure that a service negotiation protocol takes account of these resources so that the response to a specific service deployment request from the end-user is consistent and predictable. To promote the acceleration of service deployment by means of Active Networking technology, a pricing model is also evaluated for computational resources (e.g., CPU time and memory). Previous work in these areas of research only concentrate on bandwidth (i.e., communication) - related resources. Our pricing approach takes account of both guaranteed and best-effort service by adapting the arbitrage theorem from financial theory. The central tenet for our approach is to synthesise insights from different disciplines to address problems in data networks. The greater parts of research experience have been obtained during direct and indirect participation in the 1ST-10561 project known as FAIN (Future Active IP Networks) and ACTS-AC338 project called MIAMI (Mobile Intelligent Agent for Managing the Information Infrastructure). The Inter-domain Manager (IDM) component was integrated as an integral part of the FAIN policy-based network management systems (PBNM). Its monitoring component (developed during the MIAMI project) learns about routing changes that occur within a domain so that the management system and the managed nodes have the same topological view of the network. This enabled our reservation mechanism to reserve resources along the existing route set up by whichever underlying routing protocol is in place

    COIN@AAMAS2015

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    COIN@AAMAS2015 is the nineteenth edition of the series and the fourteen papers included in these proceedings demonstrate the vitality of the community and will provide the grounds for a solid workshop program and what we expect will be a most enjoyable and enriching debate.Peer reviewe

    Now for the long term: the report of the Oxford Martin Commission for Future Generations

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    This report is the product of a year long process of research and debate undertaken by a group of eminent leaders on the successes and failures in addressing global challenges over recent decades. As the world slowly emerges from the devastating Financial Crisis, it is time to reflect on the lessons of this turbulent period and think afresh about how to prevent future crises. The Oxford Martin Commission for Future Generations focuses on the increasing short-termism of modern politics and our collective inability to break the gridlock which undermines attempts to address the biggest challenges that will shape our future. In Now for the Long Term, they urge decision-makers to overcome their pressing daily preoccupations to tackle problems that will determine the lives of today’s and tomorrow’s generations. Dr James Martin, the founder of the Oxford Martin School, highlights that humanity is at a crossroads. This could be our best century ever, or our worst. The outcome will depend on our ability to understand and harness the extraordinary opportunities as well as manage the unprecedented uncertainties and risks.   The report identifies what these challenges are, explains how progress can be made, and provides practical recommendations. The Commission outlines an agenda for the long term. The case for action is built in three parts. The first, Possible Futures , identifies the key drivers of change and considers how we may address the challenges that will dominate this century. Next, in Responsible Futures, the Commission draws inspiration from previous examples of where impediments to action have been overcome, and lessons from where progress has been stalled. We then consider the characteristics of our current national and global society that frustrate progress. The final part, Practical Futures, sets out the principles for action and offers illustrative recommendations which show how we can build a sustainable, inclusive and resilient future for all. &nbsp

    International Soft Law

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    Although the concept of soft law has existed for years, scholars have not reached consensus on why states use soft law or even whether “soft law” is a coherent analytic category. In part, this confusion reflects a deep diversity in both the types of international agreements and the strategic situations that produce them. In this paper, we advance four complementary explanations for why states use soft law that describe a much broader range of state behavior than has been previously explained. First, and least significantly, states may use soft law to solve straightforward coordination games in which the existence of a focal point is enough to generate compliance. Second, under what we term the loss avoidance theory, moving from soft law to hard law generates higher sanctions that both deter more violations and, because sanctions in the international system are negative sum, increase the net loss to the parties. States will choose soft law when the marginal costs in terms of the expected loss from violations exceed the marginal benefits in terms of deterred violations. Third, under the delegation theory, states choose soft law when they are uncertain about whether the rules they adopt today will be desirable tomorrow and when it is advantageous to allow a particular state or group of states to adjust expectations in the event of changed circumstances. Moving from hard law to soft law makes it easier for such states to renounce existing rules or interpretations of rules and drive the evolution of soft law rules in a way that may be more efficient than formal renegotiation. Fourth, we introduce the concept of international common law (ICL), which we define as a nonbinding gloss that international institutions, such as international tribunals, put on binding legal rules. The theory of ICL is based on the observation that, except occasionally with respect to the facts and parties to the dispute before it, the decisions of international tribunals are nonbinding interpretations of binding legal rules. States grant institutions the authority to make ICL as a way around the requirement that states must consent in order to be bound by legal rules. ICL affects all states subject to the underlying rule, regardless of whether they have consented to the creation of the ICL. As such, ICL provides cooperationminded states with the opportunity to deepen cooperation in exchange for surrendering some measure of control over legal rules. These four explanations of soft law, and in particular the theory of ICL, provide a firm justification for the coherence of soft law as an analytic category. They demonstrate that legal consequences flow from a range of nonbinding international instruments, just as nonbinding documents in the domestic setting, such as legislative committee reports, often have legal consequences when, for example, used to interpret binding rules. Moreover, the theories offered in this paper explain the circumstances under which this quasi-legal characteristic of soft law will be attractive to states

    The European Union, Latin America and the Caribbean: Cartography of the Association Agreements

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    Depto. de Relaciones Internacionales e Historia GlobalFac. de Ciencias PolĂ­ticas y SociologĂ­aFALSEpu
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