Scour on Alluvial Bed Downstream of Grade-Control Structures

This paper describes an approach for predicting local scour downstream of grade control structures. The developed analysis applies the incomplete self-similarity (ISS) theory for deducing some physically based dimensionless groups controlling the geometrical pattern of the scour profile. The scour measurements available in the literature in conjunction with numerous unpublished data allow a multiregressive calibration of the ISS relationships. The experimental sample includes different bed grain-size distributions and scales of the erosive phenomenon. The results prove that the ratio between the upstream water head and the weir height is able to explain the measurements of scour depth carried out in both small- and large-scale installations. This estimation of maximum scour depth was improved, introducing variables representative of both the jet contraction and the bed particle grain-size distribution. Variables related to the longitudinal sizes of the scour profile tend to be predicted with more accuracy than those related to the scour depth and appear more influenced by the coarsest component of the alluvial bed.     

Non-repudiation analysis using LySa with annotations

This work introduces a formal analysis of the non-repudiation property for security protocols. Protocols are modelled in the process calculus LySa, using an extended syntax with annotations. Non-repudiation is verified using a Control Flow Analysis, following the same approach of Buchholtz and Gao for authentication and freshness analyses.The result is an analysis that can statically check the protocols to predict if they are secure during their execution and which can be fully automated.     

Flow-sensitive Leakage Analysis in Mobile Ambients

In this paper, we present a refinement of a Control Flow Analysis aimed at studying information flow security in the the calculus of Mobile Ambients. The improvements are achieved by making the analysis be flow-sensitive: the analysis is able to keep track of temporal dependencies of capabilities application when computing a safe approximation of the run-time topology of Mobile Ambient processes.     

Design and Modelling of Photonic Band-Gap Resonance Cavity

An optimal design of Photonic Band-Gap (PBG) based resonance cavities has been carried out and optimal design rules have been drawn by a very fast and accurate computer code, developed by the authors, implementing a new model of one-dimensional finite-size PBG materials. The model also takes into account the presence of defects; it allows to accurately determine the mode propagation constants, electromagnetic harmonics and total field distribution, transmission and reflection coefficients, forward and backward power flow, guided and radiated power and total losses due to radiation, Bragg scattering and out of plane scattering. The design of resonance cavities advancing the state of the art of commercial Dense Wavelength Division Multiplexing (DWDM) filters is performed. A great number of optical cavities have been designed and quickly simulated thanks to the fastness of the code, allowing optimal design rules to be drawn.     

Preface by the section editors

The papers in this special section present a sample of recent approaches to modeling and verification of software-based systems. This research was initially presented at the 4th International Conference on Verification, Model Checking, and Abstract Interpretation (VMCAI 03). The choice of papers for the issue was based on their merit as well as on the fact that, as a group, they represent the main current research areas in the field of software-based systems.     

Molecular basis of phospholipase A2 inhibition by petrosaspongiolide M

Petrosaspongiolide M (PM) is an anti-inflammatory marine metabolite that displays a potent inhibitory activity toward group II and III secretory phospholipase A(2) (PLA(2)) enzymes. The details of the mechanism, which leads to a covalent adduct between PLA(2) and gamma-hydroxybutenolide-containing molecules such as PM, are still a matter of debate. In this paper the covalent binding of PM to bee venom PLA(2) has been investigated by mass spectrometry and molecular modeling. The mass increment observed for the PM-PLA(2) adduct is consistent with the formation of a Schiff base by reaction of a PLA(2) amino group with the hemiacetal function (masked aldehyde) at the C-25 atom of the PM gamma-hydroxybutenolide ring. Proteolysis of the modified PLA(2) by the endoprotease LysC followed by HPLC MS analysis allowed us to establish that the PLA(2) alpha-amino terminal group of the Ile-1 residue was the only covalent binding site for PM. The stoichiometry of the reaction between PM and PLA(2) was also monitored and results showed that even with excess inhibitor, the prevalent product is a 1:1 (inhibitor:enzyme) adduct, although a 2:1 adduct is present as a minor component. The 2:1 adduct was also characterized, which showed that the second site of reaction is located at the epsilon -amino group of the Lys-85 residue. Similar results in terms of the reaction profile, mass increments, and location of the PLA(2) binding site were obtained for manoalide, a paradigm for irreversible PLA(2) inhibitors, which suggests that the present results may be considered of more general interest within the field of anti-inflammatory sesterterpenes that contain the gamma-hydroxybutenolide pharmacophore. Finally, a 3D model, constrained by the above experimental results, was obtained by docking the inhibitor molecule into the PLA(2) binding site through AFFINITY calculations. The model provides an interesting insight into the PM-PLA(2) inhibition process and may prove useful in the design of new anti-inflammatory agents that target PLA(2) secretory enzymes.     

Analysis and comparison of a speed-dependant and a torque-dependant mechanical device for wide constant power speed range in AFPM starter/alternators

In this paper, two methods for flux linkage regulation in a starter/alternator with an axial-flux permanent magnet (AFPM) machine are proposed and compared. Desired regulation is achieved by two different mechanical solutions, each of them capable of modifying the amount of flux linkage through displacement of the two rotors in the AFPM machine. Constant power generation is thus achieved with very inexpensive devices that do not require external energy sources since energy in the airgap doesn't change. The main difference between the two proposed solutions is that the speed dependant device is ideally a constant voltage source while the torque-dependant device behaves as a constant current source. Even if some improvements are still needed, both devices introduce the totally innovative concept of mechanical flux weakening for AFPM power regulation in a wide speed range. Finally, the paper demonstrates that the introduction of these devices doesn't modify machine behavior in starting mode, so that the particular features of AFPM machines in terms of high torque density and overload capability remain unaffected.     

Theoretical characterization of multilayer photonic crystals having a 2D periodicity

We present a new, very accurate and fast model of photonic bandgap (PBG) structure characterized by a two‐dimensional (2D) periodic change of the refractive index and finite height, therefore named quasi 3D PBG. The new model is based on the Floquet–Bloch formalism and allows to find all the propagation characteristics including the space harmonics and the total field distribution, the propagation constants, the guided and radiated power and modal loss induced by the 2D grating. A clear explanation of the physical phenomena occurring when a wave propagates inside the 2D periodic structure is presented, including the photonic bandgap formation and the radiation effects. The approach does not require any theoretical approximation, and can be applied to study rigorously any PBG‐based multilayer structures. We have applied the model to investigate several structures for both optical and microwave applications. Copyright © 2005 John Wiley & Sons, Ltd.     

Personalized emergency medical assistance for disabled people

Being able to promptly and accurately choose a proper course of action in the field is a crucial aspect of emergency response. For this reason, emergency medical services (EMS) rely on well established procedures that apply to the most frequent cases first responders encounter in their practice, but do not include special cases concerning (sensory, motor or cognitive) disabled persons. In these cases, first responders may end up applying suboptimal or possibly wrong procedures or lose precious time trying to adapt on-the-fly to the special case. This paper proposes both (i) a detailed patient model for EMS that can account for peculiar aspects of the many existing disabilities and (ii) an adaptive information system called PRESYDIUM (Personalized Emergency System for Disabled Humans) that provides tailored instructions in the field for helping medical first responders in dealing with disabled persons. More precisely, we will illustrate and discuss: (i) the design and development process of PRESYDIUM, (ii) the patient model, which is partly based on the ICF (International Classification of Functioning, Disability and Health) standard proposed by the World Health Organization, (iii) the knowledge base used by the system to provide tailored instructions to medical first responders, (iv) the Web-based architecture of the system, (v) the different interfaces??including one for mobile devices??the system provides to enable all the identified stakeholders (disabled persons, their families, clinicians, EMS call center operators, medical first responders) to easily access and possibly provide data to the system, (vi) the evaluation of the validity of the patient model and of the system usability which has been conducted with end users.