Verifiable control of a swarm of unmanned aerial vehicles

This article considers the distributed control of a swarm of unmanned aerial vehicles (UAVs) investigating autonomous pattern formation and reconfigurability. A behaviour-based approach to formation control is considered with a velocity field control algorithm developed through bifurcating potential fields. This new approach extends previous research into pattern formation using potential field theory by considering the use of bifurcation theory as a means of reconfiguring a swarm pattern through a free parameter change. The advantage of this kind of system is that it is extremely robust to individual failures, is scalpable, and also flexible. The potential field consists of a steering and repulsive term with the bifurcation of the steering potential resulting in a change of the swarm pattern. The repulsive potential ensures collision avoidance and an equally spaced final formation. The stability of the system is demonstrated to ensure that desired behaviours always occur, assuming that at large separation distances the repulsive potential can be neglected through a scale separation that exists between the steering and repulsive potential. The control laws developed are applied to a formation of ten UAVs using a velocity field tracking approach, where it is shown numerically that desired patterns can be formed safely ensuring collision avoidance

Pattern transition in spacecraft formation flying via the artificial potential field method and bifurcation theory

In recent years many new and exciting space concepts have developed around spacecraft formation flying. This form of distributed system has the advantages of being extremely flexible and robust. This paper considers the development of new control methodologies based on the artificial potential function method and extends previous research in this area by considering bifurcation theory as a means of controlling the transition between different formations. For real, safety critical applications it is important to prove the stability of the system. This paper therefore aims to replace algorithm validation with mathematical proof through dynamical systems theory. Finally we consider the transition of formations at the Sun-Earth L2 point

Distributed control of multi-robot systems using bifurcating potential fields

The distributed control of multi-robot systems has been shown to have advantages over conventional single robot systems. These include scalability, flexibility and robustness to failures. This paper considers pattern formation and reconfigurability in a multi-robot system using bifurcating potential fields. It is shown how various patterns can be achieved through a simple free parameter change. In addition the stability of the system of robots is proven to ensure that desired behaviours always occur

Energy efficient mining on a quantum-enabled blockchain using light

We outline a quantum-enabled blockchain architecture based on a consortium of quantum servers. The network is hybridised, utilising digital systems for sharing and processing classical information combined with a fibre--optic infrastructure and quantum devices for transmitting and processing quantum information. We deliver an energy efficient interactive mining protocol enacted between clients and servers which uses quantum information encoded in light and removes the need for trust in network infrastructure. Instead, clients on the network need only trust the transparent network code, and that their devices adhere to the rules of quantum physics. To demonstrate the energy efficiency of the mining protocol, we elaborate upon the results of two previous experiments (one performed over 1km of optical fibre) as applied to this work. Finally, we address some key vulnerabilities, explore open questions, and observe forward--compatibility with the quantum internet and quantum computing technologies.Comment: 25 pages, 5 figure

INTEREST GROUPS, VETO POINTS AND ELECTRICITY INFRASTRUCTURE DEPLOYMENT

In this paper we examine the effects of interest group pressure and the structure of political institutions on infrastructure deployment by state-owned electric utilities in a panel of 78 countries during the period 1970 – 1994. We consider two factors that jointly influence the rate of infrastructure deployment: (1) the extent to which the consumer base consists of industrial consumers, which are capable of exerting discipline on political actors whose competing incentives are to construct economically inefficient “white elephants” to satisfy the demands of concentrated geographic interests, labor unions and construction firms; and (2) veto points in formal policymaking structures that constrain political actors, thereby reducing these actors’ sensitivity to interest group demands. A higher fraction of industrial customers provides political actors with stronger incentives for discipline, reducing the deployment of white elephants and thus the infrastructure growth rate, ceteris paribus. Veto points reduce political actors’ sensitivity to interest group demands in general and thus moderate the relationship between industrial interest group pressure and the rate of infrastructure deployment.http://deepblue.lib.umich.edu/bitstream/2027.42/40097/3/wp711.pd

Swarm shape manipulation through connection control

The control of a large swarm of distributed agents is a well known challenge within the study of unmanned autonomous systems. However, it also presents many new opportunities. The advantages of operating a swarm through distributed means has been assessed in the literature for efficiency from both operational and economical aspects; practically as the number of agents increases, distributed control is favoured over centralised control, as it can reduce agent computational costs and increase robustness on the swarm. Distributed architectures, however, can present the drawback of requiring knowledge of the whole swarm state, therefore limiting the scalability of the swarm. In this paper a strategy is presented to address the challenges of distributed architectures, changing the way in which the swarm shape is controlled and providing a step towards verifiable swarm behaviour, achieving new configurations, while saving communication and computation resources. Instead of applying change at agent level (e.g. modify its guidance law), the sensing of the agents is addressed to a portion of agents, differentially driving their behaviour. This strategy is applied for swarms controlled by artificial potential functions which would ordinarily require global knowledge and all-to-all interactions. Limiting the agents' knowledge is proposed for the first time in this work as a methodology rather than obstacle to obtain desired swarm behaviour

INTEREST GROUPS, VETO POINTS AND ELECTRICITY INFRASTRUCTURE DEPLOYMENT

In this paper we examine the effects of interest group pressure and the structure of political institutions on infrastructure deployment by state-owned electric utilities in a panel of 78 countries during the period 1970 – 1994. We consider two factors that jointly influence the rate of infrastructure deployment: (1) the extent to which the consumer base consists of industrial consumers, which are capable of exerting discipline on political actors whose competing incentives are to construct economically inefficient “white elephants” to satisfy the demands of concentrated geographic interests, labor unions and construction firms; and (2) veto points in formal policymaking structures that constrain political actors, thereby reducing these actors’ sensitivity to interest group demands. A higher fraction of industrial customers provides political actors with stronger incentives for discipline, reducing the deployment of white elephants and thus the infrastructure growth rate, ceteris paribus. Veto points reduce political actors’ sensitivity to interest group demands in general and thus moderate the relationship between industrial interest group pressure and the rate of infrastructure deployment.Electricity, Institutional Environment, Investment, Regulation, interest group, state owned enterprise

Resistance to multilateral influence on reform : the political backlash against private infrastructure investments

Coercive isomorphism is a prominent source of institutional change. The literature to date has emphasized how actors that are powerful and legitimate (for example, a national government) may coerce the adoption of reforms by dependent actors (for example, state governments and other organizations whose activities are governed by the federal government). The authors observe that an actor's power alone may be sufficient to promote reform, regardless of the actor's legitimacy. But such reforms are more susceptible to subsequent change than those that emerge from processes not subject to the influence of external actors whose sway derives from their power alone. They develop and test their arguments in the context of the worldwide electricity provision industry by analyzing countries'adoption of reforms in response to conditional lending practices by multilateral organizations such as the World Bank and the International Monetary Fund. The authors find that reforms adopted in response to coercive pressures exerted by these organizations encounter much greater resistance, and that the incidence of financial and economic crises, the absence of checks and balances in established political institutions, and the inexperience of investor coalitions dramatically increase the predicted level of resistance.National Governance,Health Monitoring&Evaluation,ICT Policy and Strategies,Politics and Government,Governance Indicators

Legitimacy, Interest Group Pressures and Change in Emergent Institutions: The Case of Foreign Investors and Host Country Governments

We offer a simple model of policymaking emphasizing socialization and limits on human cognition to explicate mechanisms of change in emergent (as opposed to established) institutions. Emergent institutions are more susceptible to change, and their opponents may use frames or existing reference points to illustrate inconsistency with prevailing notions of legitimacy. Broader institutional structures and specific organizational characteristics moderate pressure for change. This perspective has novel implications for strategy and policy design.