An infrastructure to support cooperation of knowledge-level agents on the semantic Grid

Can a Knowledge-Level layer be located in the Semantic Grid infrastructure? Is it possible to design an Agent Communication Language (ACL) which enables Knowledge-Level agents to cooperate in a geographically distributed Semantic Grid despite nodes’ failures or malfunctions? This paper tries to address the above Semantic Grid challenges presenting an agent-based Open Service Architecture which integrates geographically distributed agents in a Semantic Grid. The architecture is well integrated with standard Internet components and technologies and supports communication among Knowledge-Level agents. The role of agents is to retrieve, execute and compose available services providing more sophisticated instances of them. Inter-agent communication is realized by exploiting an advanced Agent Communication Language which supports a fault-tolerant anonymous interaction protocol and satisfies a set of well defined Knowledge-Level programming requirements. Here, we present the design of the architecture and of the Agent Communication Language as well as their implementation. The architecture is evaluated by means of several case studies which highlight the main feature of our proposal. The main advantage of our approach is to demonstrate that different issues, such as high level inter-agent communication and fault tolerance, can be successfully integrated in Grid infrastructures which provide Web Services maintaining a clean design of the architecture and a Knowledge-Level characterization.     

IEN-CsF1 accuracy evaluation and two-way frequency comparison

In this paper we report the accuracy evaluation of the Italian primary frequency standard IEN-CsF1. We discuss the shifts the frequency standard is corrected for and the procedure used for the accuracy evaluation. In the last section we report frequency comparisons of our fountain with those of remote laboratories and with International Atomic Time.     

TETRA radio performance evaluated via the software package TETRASIM

TETRA (TErrestrial Trunked RAdio) is a digital mobile radio standard for voice and data transmission. It aims at satisfying the growing request of applications and facilities coming from professional users and emergency services. The system has been standardized by ETSI (European Telecommunications Standards Institute) and is provided with an European harmonized frequency band. The first TETRA networks appeared on the market in 1997. This paper reports TETRA radio performance evaluated via a simulation software package, named TETRASIM, entirely developed at CSELT according to TETRA specifications. The simulation results have been obtained for some of the traffic and control channels specified by the standard, in terms of BER (Bit Error Rate) and MER (Message Erasure Rate). As far as the simulated receiver scheme is concerned, the characteristics of the equivalent low-pass filters and the adopted synchronization technique are reported. The simulated demodulator uses a differential detection scheme with soft decision outputs in the case of coded channels. Performance analyses and results comparison are provided by taking into account the effects of signal-to-noise ratio, co-channel interference, adjacent channel interference, propagation models defined in the standard and mobile unit speed. The simulation results reported in this work have been included in the ETR (ETSI Technical Report) “TETRA Designers’ Guide Part 2: Radio and Traffic Performance”. This revised version was published online in June 2006 with corrections to the Cover Date.     

Unbundling dynamic capabilities: an exploratory study of continuous product innovation

In order to understand better the organizational sources ofcontinuous innovation, this paper provides an in-depth analysisof Oticon A/S, a leading company in the hearing-aid industry,which showed an impressive ability to develop new products inthe nineties. Findings highlight that dynamic capabilities aremade up of: knowledge creation and absorption, knowledge integrationand knowledge reconfiguration. Discussion links the findingsto previous literature and shows how these knowledge-based processesare all based on a coherent mix of organizational resources.     

The emergence of communication in evolutionary robots

Evolutionary robotics is a biologically inspired approach to robotics that is advantageous to studying the evolution of communication. A new model for the emergence of communication is developed and tested through various simulation experiments. In the first simulation, the emergence of simple signalling behaviour is studied. This is used to investigate the inter-relationships between communication abilities, namely linguistic production and comprehension, and other behavioural skills. The model supports the hypothesis that the ability to form categories from direct interaction with an environment constitutes the grounds for subsequent evolution of communication and language. In the second simulation, evolutionary robots are used to study the emergence of simple syntactic categories, e.g. action names (verbs). Comparisons between the two simulations indicate that the signalling lexicon emerged in the first simulation follows the evolutionary pattern of nouns, as observed in related models on the evolution of syntactic categories. Results also support the language-origin hypothesis on the fact that nouns precede verbs in both phylogenesis and ontogenesis. Further extensions of this new evolutionary robotic model for testing hypotheses on language origins are also discussed.     

A 0.18 μm CMOS direct down-converter for highly integrated 3G receivers

This paper presents the design of a high dynamic range direct down-converter for 3G cell-phone applications. The mechanisms responsible for second-order intermodulation distortion are discussed in details, leading to the following design strategy: the transconductor is degenerated by means of an RC filter, an LC network resonating at RF frequency loads the switching pair and carefully matched resistors are used in the output load. Prototypes realized in 0.18 μm CMOS show: +78 dBm IIP2 minimum among 40 samples, +10 dBm IIP3, 4 nV/√Hz input-referred noise density while burning only 4 mA from 1.8 V.     

A GRASP with path-relinking heuristic for the survivable IP/MPLS-over-WSON multi-layer network optimization problem

In this paper we deal with the survivable internet protocol (IP)/multi-protocol label switching (MPLS)-over-wavelength switched optical network (WSON) multi-layer network optimization problem (SIMNO). This problem entails planning an IP/MPLS network layer over a photonic mesh infrastructure whilst, at the same time, ensuring the highest availability of services and minimizing the capital expenditures (CAPEX) investments. Such a problem is currently identified as an open issue among network operators, and hence, its solution is of great interest. To tackle SIMNO, we first provide an integer linear programming (ILP) formulation which provides an insight into the complexity of its managing. Then, a greedy randomized adaptive search procedure (GRASP) with path-relinking (PR) together with a biased random-key genetic algorithm (BRKGA) are specifically developed to help solve the problem. The performance of both heuristics is exhaustively tested and compared making use of various network and traffic instances. Numerical experiments show the benefits of using GRASP instead of BRKGA when dealing with highly complex network scenarios. Moreover, we verified that the use of GRASP with PR remarkably improves the basic GRASP algorithm, particularly in real-sized, complex scenarios such as those proposed in this paper.     

A systematic review on the functional testing of semantic web services

Semantic web services are gaining more attention as an important element of the emerging semantic web. Therefore, testing semantic web services is becoming a key concern as an essential quality assurance measure. The objective of this systematic literature review is to summarize the current state of the art of functional testing of semantic web services by providing answers to a set of research questions. The review follows a predefined procedure that involves automatically searching 5 well-known digital libraries. After applying the selection criteria to the results, a total of 34 studies were identified as relevant. Required information was extracted from the studies and summarized. Our systematic literature review identified some approaches available for deriving test cases from the specifications of semantic web services. However, many of the approaches are either not validated or the validation done lacks credibility. We believe that a substantial amount of work remains to be done to improve the current state of research in the area of testing semantic web services.     

Using C/X-band SAR interferometry and GNSS measurements for the Assisi landslide analysis

This work presents an analysis of the applicability of synthetic aperture radar (SAR) interferometry to landslide monitoring. This analysis was carried out by using different interferometric approaches, different spaceborne SAR data (both in the C-band and in the X-band), and in situ global navigation satellite system (GNSS) measurements. In particular, we investigated both the reliability of displacement monitoring and the issues of the cross-comparison and validation of the interferometric synthetic aperture radar (InSAR) results. The work was focused on the slow-moving landslide that affects a relevant part of the urban area of the historical town of Assisi (Italy).

A C-band ENVISAT advanced synthetic aperture radar (ENVISAT ASAR) dataset acquired between 2003 and 2010 was processed by using two different interferometric techniques, to allow cross-comparison of the obtained displacement maps. Good correspondence between the results was found, and a deeper analysis of the movement field was possible. Results were further compared to a set of GNSS measurements with a 7 year overlap with SAR data. A comparison was made for each GNSS marker with the surrounding SAR scatterers, trying to take into account local topological effects, when possible.

Further, the high-resolution X-band acquired on both ascending and descending tracks by the COSMO-SkyMed (CSK) constellation was processed. The resultant displacement fields show good agreement with C-band and GNSS measurements and a sensible increase in the density of measurements.