A New Current-Mode Synthesis Method for Dynamic Translinear Filters and its Applications in Hearing Instruments

A new current mode synthesis method for dynamic translinear filters is proposed. As a design example, we have considered an ultra-low power second order filter working in audio frequency range, for hearing aids application, and using subthreshold MOS devices. It has a nominal supply voltage of 1.2 V and works down to 1 Volt. It has a power consumption of 5 W. The filter cut-off frequency and its Q factor can be tuned respectively from 600 Hz to 13 kHz and from 0.6 to 1.1. Mismatch problems are investigated on the circuit level and an on-chip compensation method is proposed.     

Real-time H.264/AVC baseline decoder implementation on TMS320C6416

The H.264/AVC Advanced Video Coding standard (AVC) is poised to enable a wide range of applications. However, its increased complexity creates a big challenge for efficient software implementations. This work develops and optimises the H.264/AVC video decoder level two on the TMS320C6416 Digital Signal Processor (DSP) for video conference applications. In order to accelerate the decoding speed, several algorithmic optimisations have been ported to inverse entropy decoding and intra-prediction modules. The parallelism between algorithm execution and data transfers was fully exploited using Enhanced Direct Memory Access (EDMA) engine. Furthermore, based on the DSP architectural features, various core-specific optimisation techniques were adopted leading to an increase in speed by up to 70%. Intensive experimental tests prove that a real-time decoding on TMS320C6416 DSP running at 720?MHz is obtained for Common Intermediate Format resolution (CIF 352?×?288).     

A decision support system assessing the trust level in supply chains based on information sharing dimensions

Assessing customer trust in suppliers with regards to its influencing factors is an important open issue in supply chain management literature. In this paper, a customer trust index is designed as the trust level arising from the information sharing degree and quality, related to the information shared by a supplier with his customer. The customer trust level is evaluated using a fuzzy decision support system integrating information sharing dimensions. The core is a rule-based system designed using the results of questionnaires and interviews with supply chain experts. Several tests were generated in order to analyze the impact of the different information sharing attributes on the customer trust index. The developed approach is then applied to a real supply chain from the textile industry. Results show large differences of weight and impact between the different information-related factors that build the customer trust index. It is also shown that the proposed system has an important role in ensuring the objectivity of the trust assessment process and in helping decision makers evaluate their business partners.     

Simultaneous Actuator and Sensor Faults Reconstruction Based on Robust Sliding Mode Observer for a Class of Nonlinear Systems

This paper proposes a new robust fault reconstruction and estimation design for a class of nonlinear system described by the Takagi‐Sugeno model with unmeasurable premise variables subject to faults affecting actuators, sensor faults, and unknown disturbances. The augmented Takagi‐Sugeno system is introduced with a new fault vector which has two origins: the first one represents actuator faults, the second one denotes faults affecting sensors. The main contribution is focused primarily to conceive a sliding mode observer with two discontinuous terms designed to compensate for fault behavior and disturbance variation from the system states estimation. In the formalism of linear matrix inequalities, we derive sufficient conditions to guarantee the state estimation error stability and to obtain the observer gains. Meanwhile, additional effort is made to achieve simultaneous faults and disturbance reconstruction. Simulation results are given to illustrate the proposed approach performances.     

A multiple objective stochastic portfolio selection problem with random Beta

When selecting a portfolio, we need to consider, in general, the portfolio return and portfolio risk. Many risk measures have been used in portfolio selection problems as the Beta risk measure, introduced by the capital asset pricing model. Most of the existing research papers suppose that security's Beta has a deterministic value. Recently, many researchers argued that in selecting the optimal portfolio, securities’ Beta should be considered as an uncertain parameter. In this paper, we set up fundamentals to model the portfolio's Beta as a random variable and propose a multiple objective stochastic portfolio selection model with random Beta. To solve the proposed model, we apply a stochastic goal programming approach. A numerical example from the US stock exchange market is reported.     

Transverse Thermal Expansion of FRP Bars Embedded in Concrete

Fiber reinforced polymers (FRPs) have a thermal expansion in the transverse direction much higher than in the longitudinal direction and also higher than the thermal expansion of hardened concrete. The difference between the transverse coefficient of thermal expansion of FRP bars and concrete may cause splitting cracks within the concrete under temperature increase and, ultimately, failure of the concrete cover if the confining action of concrete is insufficient. This paper presents the results of an experimental investigation to analyze the effect of the ratio of concrete cover thickness to FRP bar diameter (c/db) on the strain distributions in concrete and FRP bars, using concrete cylindrical specimens reinforced with a glass FRP bar and subjected to thermal loading from ?30?to?+80°C. The experimental results show that the transverse coefficient of thermal expansion of the glass FRP bars tested in this study is found to be equal to 33 (×10?6?mm/mm/°C), on average and the ratio between the transverse and longitudinal coefficients of thermal expansion of these FRP bars is equal to 4. Also, the cracks induced by high temperature start to develop on the surface of concrete cylinders at a temperature varying between +50 and +60°C for specimens having a ratio of concrete cover thickness to bar diameter c/db less than or equal to 1.5. A ratio of concrete cover thickness to glass fiber reinforced polymers (GFRP) bar diameter c/db greater than or equal to 2.0 is sufficient to avoid cracking of concrete under high temperature up to +80°C. The analytical model, presented in this paper, is in good agreement with the experimental results, particularly for negative temperature variations.     

Efficient MLP constructive training algorithm using a neuron recruiting approach for isolated word recognition system

This paper describes an efficient constructive training algorithm using a Multi Layer Perceptron (MLP) neural network dedicated for Isolated Word Recognition (IWR) systems. Incremental training procedure was employed and this approach was based on novel hidden neurons recruiting for a single hidden-layer. During Neural Network (NN) training phase, the number of pronunciation samples extracted from the Training Data (TD) was sequentially increased. Optimal structure of the NN classifier with optimized TD size was obtained using this proposed MLP constructive training algorithm.     

Structural and optical properties of CdGa2Se4 thin films

CdGa₂Se₄ thin films were prepared by vapour deposition onto either room temperature or preheated quartz and glass substrates (T _S) or they were deposited at room temperature and then annealed at about (T _A) 623 K. The films thus prepared were crystalline with a thiogallate tetragonal structure. The optical constants (the refractive index n and the absorption index, k) were determined for CdGa₂Se₄ films deposited onto quartz substrates held at either room temperature or at T _S = 573 K. These constants were also determined for preannealed films (T _A = 623 K). Plots of (hv)² = f(hv) and (hv)^1/2 = g(hv) were linear, indicating the existence of both direct and indirect optical transitions. It was found that the values of E _g ^d and E _g ^ind for as-deposited CdGa₂Se₄ films were 2.46 and 1.91 eV, respectively. The corresponding values for the annealed films and the films deposited at T _S = 573 K were 2.56 and 2.06 eV, respectively.     

Design and Characterization of a New Food Packaging Material by Recycling Blends Virgin and Recovered polyethylene terephthalate

This research is dealing with plastic wastes recycling environmental problem. The objective is the polyethylene terephthalate (PET) valorization from postconsumer bottles by the optimization of the most suitable virgin and recycled PET mixture to be used as food contact packaging. Mixtures of these materials were elaborated by extrusion and injection molding using different recycled PET rates. Rheological, mechanical, and thermal analyses were achieved, and then migration tests were investigated to assess the recycled PET compatibility for food contact packaging. The rheological analysis showed a PET degradation after the mechanical recycling, with PET viscosity decrease, compared to that of the virgin material. The blends properties showed that at low deformation, mechanical properties were significantly improved by adding recycled PET. Consequently, the new material was more rigid with a crystallinity degree improvement, increasing the materials resistance that enhanced their tenacity. However, at great deformations, the PET mixed materials were deteriorated through drastic ductility losses. The mixture 30/70 recycled/virgin PET seems to be the best blend. For all the studied mixtures, the overall migrations conformed the European Standard, allowing the use of the recycled PET for packaging as an issue in circular economy principles for a sustainable development. POLYM. ENG. SCI., 60: 250–256, 2019. © 2019 Society of Plastics Engineers     

Drying Sage (Salvia officinalis L.) Plants and Its Effects on Content, Chemical Composition, and Radical Scavenging Activity of the Essential Oil

Chemical composition and antioxidant activity of Salvia officinalis essential oil (EO) were studied under different drying methods of plant material. Results obtained showed that dried plant material yielded more essential oils than did the fresh one. The highest EO yields were obtained by infrared drying at 45?°C (0.39%) followed by air drying (0.30%) and oven drying at 45?°C (0.26%). The analysis of EOs by gas chromatography?Cmass spectrometry, showed in each of 55 identified compounds belonging mostly to oxygenated monoterpenes. This class of compounds was significantly affected by following drying methods: oven at 65?°C, microwave (500?W), and infrared at 45?°C. The main components of sage EO, 1,8-cineole, ?? and ??-thujone, camphor, viridiflorol, and manool showed significant variation (p?<?0.05) with drying methods. Their concentrations increased significantly, particularly when drying sage at ambient air. Finally, the screening of antioxidant activity of the different sage EOs using the di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium radical (DPPH) assay showed an appreciable reduction of the stable radical DPPH, although microwave drying was the most efficient method with an IC50 of 1.60% as compared with fresh plant (IC50?=?5.32).