Recursive parser optimization by rewriting context-free grammars

The analysis of programming languages is a fundamental activity in the process of comprehending, maintaining, documenting and reengineering old software. However, the analysis may sometimes be inefficient because of the parsing methodology adopted. Prolog parsers, for instance, have two main drawbacks: the time spent on extracting information as a result of the backtracking mechanism, and the large memory occupation involved. This paper presents an algorithm that optimizes a top-down parser by imposing a set of rules on the grammar to be analyzed. A methodology is then defined for rewritting a context-free grammar (LL(n) n > = 1), and a tool that can achieve this is illustrated. This tool, called FACTOTUM, has been implemented in LPA Prolog, and works on a PC (IBM-MSDOS) through the Windows medium. FACTOTUM is composed of nearly 250 productions, and is an important part of another reverse engineering tool called RE_Tool (Giannone and Maresca, 1995) which can analyze codes in a multilanguage environment. RE_Tool has been implemented in the software engineering laboratories of DIS at the University of Naples Federico II, where it is currently under experimentation.     

Policy gradient learning for quadruped soccer robots

In real-world robotic applications, many factors, both at low level (e.g., vision, motion control and behaviors) and at high level (e.g., plans and strategies) determine the quality of the robot performance. Consequently, fine tuning of the parameters, in the implementation of the basic functionalities, as well as in the strategic decisions, is a key issue in robot software development. In recent years, machine learning techniques have been successfully used to find optimal parameters for typical robotic functionalities. However, one major drawback of learning techniques is time consumption: in practical applications, methods designed for physical robots must be effective with small amounts of data. In this paper, we present a method for concurrent learning of best strategy and optimal parameters using policy gradient reinforcement learning algorithm. The results of our experimental work in a simulated environment and on a real robot show a very high convergence rate.     

Pulse tail suppression in laser diode output by tunable notchfilter

Efficient suppression of the relaxation oscillations in the output signal from an overdriven gain-switched laser diode is demonstrated for the first time by spectral filtering using a nonuniformly strained Fibre Bragg grating. As a result, a five-fold increase in the peak power is achieved for the tail-free operation     

Quality Characteristics of Wholemeal Flour and Bread from Durum Wheat (Triticum turgidum L subsp. durum Desf.) after Field Treatment with Plant Water Extracts

The use of selected plant water extracts to control pests and weeds is gaining growing attention in organic and sustainable agriculture, but the effects that such extracts may exert on the quality aspects of durum wheat are still unexplored. In 2014, 5 plant water extracts (Artemisia arborescens, Euphorbia characias, Rhus coriaria, Thymus vulgaris, Lantana camara) were prepared and distributed on durum wheat cv Valbelice to evaluate their potential herbicidal effects. After crop harvesting, the major physicochemical and technological parameters of wholemeal flours obtained from each treatment were measured and compared with those from chemical weeding and untreated controls. A baking test was also performed to evaluate the breadmaking quality. In wholemeal flours obtained after the treatment with plant extracts protein and dry gluten content were higher than in control and chemical weeding. Wholemeal flours obtained after chemical weeding reached the highest Mixograph parameters, and that from durum wheat treated with R. coriaria extract demonstrated a very high α‐amylase activity. We concluded that the treatments with plant water extracts may influence many quality traits of durum wheat. This occurrence must be taken into account in overall decisions concerning the use of plant extracts in pest and weed management practice.     

PDMS microfluidics developed for polymer based photonic biosensors

In this work, advances in the fabrication technology and functional analysis of a polymer microfluidic system—as a significant part of a developed polymer photonic biosensor—are reported. Robust and cost-effective microfluidics in PDMS including sample preparation functions is designed and realized by using SU-8 moulding replica. Surface modification strategies using Triton X-100 and PDMS-PEO and their effect on device sealing and non-specific protein adsorption are investigated by contact angle measurement and in situ fluorescence microscopy.     

A programmable optical network testbed in support of C-RAN: a reliability study

With both mobile network services and related data traffic volume on the rise, reliability of the radio access network is of the essence. A number of radio functional splits are defined by 3GPP to offer increased flexibility of implementation and feasibility of new mobile network services. For example, it is possible to implement certain radio functions in the Cloud, an architectural solution referred to as C-RAN. C-RAN solutions require highly reliable backhaul and fronthaul network designs. This paper describes PROnet, a programmable optical software-defined network testbed, which has been upgraded to offer backhaul and fronthaul transport capabilities in support of C-RAN functionalities with increased reliability. The testbed is upgraded with a specially designed 1 + 1 protection mechanism at the Ethernet layer in order to meet the stringent network round-trip requirements imposed by one of the C-RAN functional split options on the fronthaul.

     

Wavelength-switchable single-frequency erbium-doped fiber ring laser

We demonstrate a single-frequency and wavelength-switchable fiber ring laser obtained by a Lyot filter used in combination with a sampled fiber Bragg grating and a saturable absorber. The operating wavelength of the laser can be tuned, with a constant 0.8-nm step, in the range 1552.6-1555.8 nm. The tuning mechanism works on the rotation of the polarization of Lyot filter input signal. The structure of the laser is very simple regarding its characteristics: an output power of 6 dBm, with a signal-to-noise ratio higher than 60 dB and a spectral linewidth of 8 kHz.     

Optimization of a bolometer detector for ITER based on Pt absorber on SiN membrane

Any plasma diagnostic in ITER must be able to operate at temperatures in excess of 200?°C and neutron loads corresponding to 0.1 dpa over its lifetime. To achieve this aim for the bolometer diagnostic, a miniaturized metal resistor bolometer detector based on Pt absorbers galvanically deposited on SiN membranes is being developed. The first two generations of detectors featured up to 4.5?μm thick absorbers. Results from laboratory tests are presented characterizing the dependence of their calibration constants under thermal loads up to 450?°C. Several detectors have been tested in ASDEX Upgrade providing reliable data but also pointing out the need for further optimization. A laser trimming procedure has been implemented to reduce the mismatch in meander resistances below 1% for one detector and the thermal drifts from this mismatch.     

Experimental optimisation of central wavelength and bandwidth of reflective FBG for efficiency improvement of low-noise L-band EDFAs

Operation of L-band erbium-doped fibre amplifiers (EDFAs) incorporating a reflective amplified spontaneous emission filter (fibre Bragg grating (FBG)) was emulated with a tunable source. The experimental optimisation of the FBG bandwidth and central wavelength led to a low noise (<5.2 dB) 20 dBm single-pumped WDM EDFA.     

Actively mode-locked tunable dual-wavelength erbium-doped fiberlaser

We report an actively mode-locked tunable dual-wavelength erbium-doped fiber laser that uses parallel amplifiers in order to minimize gain cross-saturation effects. We obtain extremely stable, room-temperature dual-wavelength operation at a modulator drive frequency of 1035.38 MHz (corresponding pulsewidths of 115 and 130 ps). Furthermore, we can independently tune the power and wavelength of each lasing output signal without affecting overall output stability. In particular, we achieve a wavelength separation as narrow as 0.3 nm