The Computer Misuse Act 1990: lessons from its past and predictions for its future

The age of the internet has thrown down some real challenges to the Computer Misuse Act 1990. Recently, the Government made changes to this piece of legislation, in an attempt to meet two of those challenges--the proliferation of “ Denial of Service” (DoS) attacks, and the creation and dissemination of “ Hackers' tools” --and to fulfil international commitments on cybercrime. Yet some of these new measures invite criticisms of policy, form and content, and bring doubts about how easy to interpret, and how enforceable, they will be

The lifetime of electrons, holes and excitons before self-trapping

In this paper we discuss the self-trapping of a carrier or exciton in an insulator. The qualitative differences between small self-trapped molecular polarons and dielectric polarons are stressed. We point out that, for the formation of a molecular polaron or selftrapped exciton, a potential barrier must be penetrated or surmounted by the configuration coordinate, leading to a delay in the self-trapping process. This does not exist for dielectric polarons. The observable consequence of the delay time before self-trapping is discussed, and applications are made to alkali halides and to SOz

Inkjet printing of non-Newtonian fluids

Jet breakup is strongly affected by fluid rheology. In particular,small amounts of polymer can cause substantially different breakup dynamics compared to a Newtonian jet, influencing in-flight fragmentation and detachment from the nozzle. Significant concentrations may also impede jettability. Furthermore, most commercial and industrial inks are inherently colloidal due to the presence of pigment and other additives. Fluids containing a particulate phase are normally shear-thinning and so may have a different characteristic viscosity within the nozzle compared to the ejected ligament. We have developed numerical simulations using a Lagrangian finite element method that captures the free surface automatically, and admits a variety of viscosity dependences, e.g. on the local shear rate (generalized Newtonian fluid) or on the particle concentration (Krieger-Dougherty type models), in addition to several viscoelastic models for polymeric fluids. This method has been benchmarked against experimental data for Newtonian jets. Appropriate rheological models are discussed, and results are presented alongside comparisons with experimental work

Growth, volatility and political instability: Non-linear time-series evidence for Argentina, 1896-2000

What is the relationship between economic growth and its volatility? Does political instability affect growth directly or indirectly, through volatility? This paper tries to answer such questions using a power-ARCH framework with annual time series data for Argentina from 1896 to 2000. We show that while assassinations and strikes (what we call “informal” political instability) have a direct negative effect on economic growth, “formal” political instability (constitutional and legislative changes) has an indirect (through volatility) negative impact. We also find preliminary support for the idea that while the effects of “formal” instability are stronger in the long-run, those of “informal” instability are stronger in the short-run

Monitoring and management of power transmission dynamics in an industrial smart grid

This article is a position paper whose purpose is to give the context for presentations in a special session at PowerTech 2013. The special session is being proposed by the EU FP7 Real-Smart Consortium, a Marie Curie Industry-Academic Pathways and Partnerships project. The paper gives an overview of topics on modeling, monitoring and management of power transmission dynamics with participation from large industrial loads. © 2013 IEEE

Closed loop identification based on quantization

This paper proposes a new closed-loop identification scheme for a single-input-single-output control loop. It is based upon a quantizer inserted into the feedback path. The quantizer can be used to generate an equivalent persistently exciting signal with which the well known two-stage and/or two-step method can be used directly. Simulation examples and an experimental demonstration are used to illustrate the proposed scheme

Frequency Restoration Reserve Control Scheme with Participation of Industrial Loads

In order to accommodate larger amounts of renewable energy resources, whose power output is inherently unpredictable, there is an increasing need for frequency control power reserves. Loads are already used to provide replacement reserves, i.e. the slowest kind of reserves, in several power systems. This paper proposes a control scheme for frequency restoration reserves with participation of industrial loads. Frequency restoration reserves are required to change their active power within a time frame of tens of seconds to tens of minutes in response to a regulation signal. Industrial loads in many cases already have the capacity and capability to participate in this service. A mapping of their process constraints to power and energy demand is proposed in order to integrate industrial loads in existing control schemes. The proposed control scheme has been implemented in a 74-bus test system. Dynamic simulations show that industrial loads can be successfully integrated into the power system as frequency restoration reserves. © 2013 IEEE

Performance assessment and diagnosis of refinery control loops

This paper discusses the application of control loop performance assessment (Desborough and Harris, 1992) in a refinery setting. In a large process it is not feasible to tailor the parameters of the algorithm to every individual control loop. A procedure is illustrated for selecting default values which make it possible to implement the technology on a refinery-wide scale. For instance, it is shown that the prediction horizon perameter in the CLPA algorithm can be set so that the analysis is sensitive to the persistent signals that cause loss of performance. Default values are suggested for refinery applications.A frequent cause of loss of performance in a control loop is a persistent oscillation due to a valve nonlinearity or a tuning fault. The paper presents an operational signatures in the form of an estimate of the closed loop impulse response that suggest the causes of such oscillations