Developing Real Applications With Agent Technologies

In this paper, we present an agent library to develop multi-agent applications. Such an agent library has been realised taking into account FIPA specifications. FIPA specifications give the minimum amount of technology deemed necessary for the management of agents in an open agent system, including agent roles, an agent communication language, an agent management content language, and a standard way to interact with non-agentised software.Therefore, the library offers the prototypes of the agents necessary for the management of a FIPA agent open system and an agent prototype that the user can specialise to build the other agents necessary for her/his application. The library has been implemented both in C++ and Java. The two implementations support a logical distribution, i.e., the agents correspond to different threads, and a physical distribution, i. e., agents of the same applications run on different machines. The Java library has been used to develop a multi-agent system, that facilitates users to use a video on demand service, and a first prototype of the system is under experimentation. The C++ library is used for the development of a multi-agent system that should integrate the different software modules performing sensory data interpretation, planning, faults diagnosis, . . . of a robot working in a space station.     

Noonan syndrome: structural abnormalities of the mitral valve causing subaortic obstruction

Among 41 consecutive children with classic Noonan syndrome, 27 patients (66%) presented cardiac anomalies. Eight patients (19.5%) had a congenital anomaly of the mitral valve consisting of 5 with partial atrioventricular canal defect and 3 with anomalous insertion of the mitral valve on the ventricular septum. Five patients (12%) presented with a significant left ventricular outflow tract obstruction caused by the anterior leaflet of the mitral valve: two cases with atrioventricular canal and three cases with isolated anomalous insertion of the mitral valve. Echocardiography is the best tool for the diagnosis. Cardiac defects of patients with Noonan syndrome may be explained on the basis of anomalies of the extracellular matrix involving cardiac valves including the mitral valve. CONCLUSION: In children with Noonan syndrome and left ventricular hypertrophy a careful echocardiographic assessment of the mitral valve should reveal those in whom the left ventricular outflow tract obstruction is anatomical in nature.     

Liquid electrolyte positioning along the device channel influences the operation of Organic Electro-Chemical Transistors

In this work, we show the influence of the liquid electrolyte adsorption by porous films made of poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonate), PEDOT:PSS, on the operation of an Organic Electro-Chemical Transistor with an active channel based on these polymeric films. In particular, the effect of film hydration on device performance is evaluated by studying its electrical response as a function of the spatial position between the electrolyte and the channel electrodes. This is done by depositing a PEDOT:PSS film on a super-hydrophobic surface aimed at controlling the electrolyte confinement next to the electrodes. The device response shows that the confinement of ionic liquids near to the drain electrode results in a worsening of the current modulation. This result has been interpreted in the light of studies dealing with the transport of ions in semiconducting polymers, indicating that the electrolyte adsorption by the polymeric film implies the formation of liquid pathways inside its bulk. These pathways, in particular, affect the device response because they are able to assist the drift of ionic species in the electrolyte towards the drain electrode. The effect of electrolyte adsorption on the device operation is confirmed by means of moving-front measurements, and is related to the reproducibility of the device operation curves by measuring repeatedly its electrical response.     

On-field test campaign performance of VDE-SAT Link ID 20 over Norsat-2 LEO satellite

The latest technical recommendation by the International Telecommunication Union (ITU) for a data exchange system in the VHF maritime mobile band defines a random access channel (RAC) for communications on the uplink channel between vessels and satellites. The physical layer frame for random uplink channel is designed to allow for a more efficient use of the power amplifiers and includes features to assist the satellite receivers to resolve overlapping reception of multiple messages. This paper presents the performance results of an over-the-air test campaign carried out exploiting the NorSat-2 Low Earth orbit (LEO) satellite. After a review of the VDE-SAT RAC and Link ID 20 burst, a possible demodulator implementation is shown. Then, the VDE-SAT transmitter platform, located in Pisa, Italy, emulating a population of vessels transmitting to the NorSat-2 LEO satellite is introduced, and the test cases are described. Afterward, the analysis of the recorded signals is provided. The post-analysis first focuses on the demodulation performance in terms of probability of successful demodulation of the interfering bursts. Further investigation has also been carried out to better understand the interference environment in this frequency band for satellite signal reception. Tests indicate promising results of successfully detecting and demodulating up to 22 overlapping RAC messages, confirming the robustness of the protocol. Finally, capitalizing on the above analysis, conclusions suggest possible improvements.     

How to standardize (if you must)

In many situations we are interested in appraising the value of a certain characteristic for a given individual relative to the context in which this value is observed. In recent years this problem has become prominent in the evaluation of scientific productivity and impact. A popular approach to such relative valuations consists in using percentile ranks. This is a purely ordinal method that may sometimes lead to counterintuitive appraisals, in that it discards all information about the distance between the raw values within a given context. By contrast, this information is partly preserved by using standardization, i.e., by transforming the absolute values in such a way that, within the same context, the distance between the relative values is monotonically related to the distance between the absolute ones. While there are many practically useful alternatives for standardizing a given characteristic across different contexts, the general problem seems to have never been addressed from a theoretical and normative viewpoint. The main aim of this paper is to fill this gap and provide a conceptual framework that allows for this kind of systematic investigation. We then use this framework to prove that, under some rather weak assumptions, the general format of a standardization function can be determined quite sharply.     

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.     

An approach to support SMEs in manufacturing knowledge organization

Different kinds of technological data are available in manufacturing enterprises, concerning the resources available as well as the processes and the components needed for the production of specific products. These data usually are not stored in a centralized knowledge management system, thus one of the main problem of managers, especially in small enterprises, is to efficiently manage their data and reuse the knowledge deriving from previous products when a new product has to be produced. Starting form the analysis of the technological data available in manufacturing enterprises, we defined a formal model as set of matrices; their analysis allows the definition of a data model to structure the technological information. The model is at the basis of the proposed system, called manufacturing knowledge organization (MAKO) to support managers in structuring and reusing the technological knowledge available in their enterprise. A prototype of the MAKO system was implemented by using open-source software and its potentialities are shown in a case study.     

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.     

On-line fault detection in discrete event systems by Petri nets and integer linear programming

The paper addresses the fault detection problem for discrete event systems in a Petri Net (PN) framework. Assuming that the structure of the PN model and the initial marking are known, faults are modelled by unobservable transitions. Moreover, we assume that there may be additional unobservable transitions associated with the system legal behaviour and that the marking reached after the firing of any transition is unknown. The proposed diagnoser works on-line: it waits for the firing of an observable transition and employs an algorithm based on the definition and solution of some integer linear programming problems to decide whether the system behaviour is normal or exhibits some possible faults. The results characterize the properties that the PN modelling the system fault behaviour has to fulfill in order to reduce the on-line computational effort.