Francesco Aiello

A Java-Based Agent Platform for Programming Wireless Sensor Networks†

Wireless sensor networks (WSNs) are emerging as powerful platforms for distributed embedded computing supporting a variety of high-impact applications. However, programming WSN applications is a complex task that requires suitable paradigms and technologies capable of supporting the specific characteristics of such networks which uniquely integrate distributed sensing, computation and communication. Mobile agents are a distributed computing paradigm based on code mobility that has already demonstrated high effectiveness and efficiency in IP-based highly dynamic distributed environments. Due to their intrinsic characteristics, mobile agents may provide more benefits in the context of WSNs than in conventional distributed environments. In this paper we present the design, implementation and experimentation of MAPS (Mobile Agent Platform for Sun SPOT), an innovative Java-based framework for wireless sensor networks based on Sun SPOT technology which enables agent-oriented programming of WSN applications. The MAPS architecture is based on components that interact through events. Each component offers a minimal set of services to mobile agents that are modeled as multi-plane state machines driven by ECA rules. In particular, the offered services include message transmission, agent creation, agent cloning, agent migration, timer handling and easy access to the sensor node resources (sensors, actuators, input switches, flash memory and battery). Agent programming with MAPS is presented through both a simple example related to mobile agent-based monitoring of a sensor node and a more complex case study for real-time human activity monitoring based on wireless body sensor networks. Moreover, a performance evaluation of MAPS carried out by computing micro-benchmarks, related to agent communication, creation and migration, is illustrated.

An agent-based signal processing in-node environment for real-time human activity monitoring based on wireless body sensor networks

Nowadays wireless body sensor networks (WBSNs) have great potential to enable a broad variety of assisted living applications such as human biophysical/biochemical control and activity monitoring for health care, e-fitness, emergency detection, emotional recognition for social networking, security, and highly interactive games. It is therefore important to define design methodologies and programming frameworks which enable rapid prototyping of WBSN applications. Several effective application development frameworks have been already proposed for WBSNs designed for TinyOS-based sensor platforms, e.g. CodeBlue, SPINE, and Titan. In this paper we present an application of MAPS, an agent framework for wireless sensor networks based on the Java-programmable Sun SPOT sensor platform, for the development of a real-time WBSN-based system for human activity monitoring. The agent-oriented programming abstractions provided by MAPS allow effective and rapid prototyping of the sensor-side software. In particular, the architecture of the developed system is a typical star-based WBSN composed of a coordinator node and two sensor nodes located respectively on the waist and the thigh of the monitored assisted living. The coordinator relies on a JADE-based enhancement of the SPINE coordinator and allows configuring sensors, receiving their data, and recognizing pre-defined human activities. On the other hand, each sensor node runs a MAPS-based agent that performs sensing of the 3-axial accelerometer sensor, computation of significant features on the acquired data, feature aggregation and transmission to the coordinator. The experimentation phase of the prototype, which allows evaluating the obtainable monitoring performances and activity recognition accuracy, is described. Moreover, a comparison of the monitoring system based on MAPS, AFME and SPINE in terms of programming effectiveness and system performances is discussed.

R&D spillovers and productivity growth: evidence from Italian manufacturing microdata

Recently the focus of R&D impact on productivity moves from internal to external innovation. This paper assesses the link between R&D spillovers and productivity of 1017 Italian manufacturing firms over 1995–2000. Different proxies of R&D spillovers and several specification tests are used to select a well-behaved fixed effect model. As predicted by various new growth theory models, external R&D exerts a positive and highly significant effect on firms’ productivity growth.

Acute bilateral angle-closure glaucoma and choroidal effusion associated with acetazolamide administration after cataract surgery

We present an interventional case report of a 76-year-old man who developed bilateral angle-closure glaucoma with extensive choroidal detachment following administration of oral acetazolamide immediately after routine cataract extraction and intraocular lens implantation. Rapid clinical improvement occurred after acetazolamide was stopped and high-dose intravenous steroid therapy was given. Although extremely rare, this adverse effect should be considered in patients who develop acute bilateral angle-closure glaucoma and choroidal effusion after cataract surgery.

R&D spillovers and firms' performance in Italy Evidence from a flexible production function

Using a translog production function we estimate the impact of R&D spillovers on the output performance of Italian manufacturing firms over the period 1998-2003. Technological flows are measured through an asymmetric similarity index that takes also into account the geographical proximity of firms. Results show that R&D spillovers positively affect firms production and that geography matters in determining the role of the external technology. Moreover, we find that the effect of R&D spillovers is high in the Centre-South of Italy and that the stock of R&D spillovers is Morishima complement to the stock of R&D own-capital.

Evaluating the impact of nonreciprocal trade preferences using gravity models

This article presents new evidence on the impact of Nonreciprocal Preferential Trade Policies (NRPTPs) granted by developed countries to exports from developing countries over the period 1995 to 2003. The analysis has been carried out by using three levels of data aggregation. It accounts for unobservable heterogeneity, endogeneity of the preferential treatment and potential selection bias. We find a positive and significant impact of NRPTPs when considering total exports and total agricultural exports. However, at 2-digit agricultural level the results are heterogeneous.

The Stabilisation of LDCs' Export Earnings. The impact of the EU STABEX programme

As part of the Lome Convention the STABEX programme is one of the instruments of the European Unions development policy. Its objective is to reduce the instability of the agricultural export earnings of the developing countries which signed the agreement. By working on a commodity-by-commodity basis, this paper provides an empirical evaluation of the effects of the financial transfers disbursed by the EU. The results obtained are substantially different from those by other authors because it is shown that STABEX does have a positive impact on the sectors in which the drop of export earnings occurred. Furthermore, it is argued that the delay concerning the payments in favour of the African Caribbean and Pacific countries (henceforth ACPs) influences the effectiveness of STABEX, even if no conclusive evidence has been found to support the widely shared opinion that the relationship between these two variables (impact of the transfers and their delays) is negative.

Java-based Mobile Agent Platforms for Wireless Sensor Networks

This paper proposes an overview and comparison of mobile agent platforms for the development of wireless sensor network applications. In particular, the architecture, programming model and basic performance of two Java-based agent platforms, Mobile Agent Platform for Sun SPOT (MAPS) and Agent Factory Micro Edition (AFME), are discussed and evaluated. Finally, a simple yet effective case study concerning a mobile agent-based monitoring system for remote sensing and aggregation is proposed. The proposed case study is developed both in MAPS and AFME so allowing to analyze the differences of their programming models.

Using Mobile Agents as Enabling Technology for Wireless Sensor Networks

Wireless sensor networks (WSNs) are emerging as powerful platforms for distributed embedded computing supporting a variety of high-impact applications. However programming WSNs is a complex task which requires suitable paradigms and technologies capable of supporting the specific characteristics of such networks which uniquely integrate distributed sensing, computation and communication. Mobile agents are a distributed computing paradigm based on code mobility that has already demonstrated high effectiveness and efficiency in IP-based highly dynamic distributed environments. We believe that mobile agents can provide more benefits in the context of WSNs than in conventional distributed environments. In this paper we first discuss the use of mobile agents as an effective enabling technology for WSN and, then, describe a lightweight framework for supporting mobile agents in WSNs.

Produttività e capitale tecnologico nel settore manifatturiero italiano

This paper estimates the impact of R&D expenditure on productivity at firm level. We use a balanced panel of 385 Italian manufacturing firms in order to provide evidence of the elasticity of capital R&D over the period 1992-1997. We consider an extended production function that includes the firms own R&D capital stock and the spillover effect as inputs, as well as labour, physical and human capital. Final outcomes confirm the relevance of R&D as a source of growth, the R&D capital elasticity being equal to 0.14.