Efficient remote access system based on decoded and decompressed speech signals

Multimedia Tools and Applications - This paper investigates the effect of both decoding and decompression on the Speaker Identification (SI) in a remote access system. The coding and compression...     

Thermal degradation study of polymethylmethacrylate with AlI3 nanoadditive

Organic polymers in the process of thermal degradation produce a lot of toxic fragments. In this work, we designed a new method of degradation of polymethylmethacrylate (PMMA) materials with aluminum triiodide nanoadditives (AlI₃ NAs). In the present research work, a thermal degradation study of PMMA blends with AlI₃ NAs was carried out by using a specially designed pyrolytic assembly. Different blends of PMMA with AlI₃ (P0, P3, P6, P9, P12, and P15) were prepared by changing the concentration of AlI₃ NAs from 0% to 15%. FTIR and TGA studies show the stability of polymers with AlI₃ NAs. Scanning electron microscopy analysis shows All₃ spread uniformly at nanoscale throughout the polymer matrix. Horizontal burning test (HBT) test confirms that polymer burning is retarded with AlI₃ NAs.     

On-column decaffeination and HPLC analysis of epigallocatechin gallate in green tea nutraceuticals

Green tea (GT) derived epigallocatechin gallate (EGCG) is a commonly used nutraceutical for its antioxidant activity. Caffeine is the second major component and interferes with extraction of EGCG. On-column decaffeination was optimized to enable selective enrichment of EGCG, though less retained than caffeine. EGCG recovery and loss in caffeine were determined using RP-HPLC. Results indicated a significant improvement in caffeine removal and EGCG recovery. The SPE-HPLC protocol represents a model for an efficient and economic approach for improving dynamic capacity, selectivity, and sensitivity towards less retained analytes. This is particularly important for analysis of inherently complex samples of nutraceutical products.     

Nested saturation based control of an actuated knee joint orthosis

Wearable robots have opened a new horizon for assistance and rehabilitation of dependent/elderly persons. The present study deals with the control of an actuated lower limb orthosis at the knee joint level. The dynamics of the shank–foot–orthosis system are expressed through a nonlinear second order model taking into account viscous, inertial and gravitational properties. Shank–foot–orthosis system parameters are identified experimentally. Since the underlying dynamic model is nonlinear, a robust control strategy is needed to guarantee an accurate and precise movement generation. The proposed control strategy ensures, at the same time, the stability of the closed-loop system. A bounded control torque is applied to guarantee the asymptotic stability of the shank–foot–orthosis. The generated control respects the physical constraints imposed by the system. The effectiveness of the proposed control strategy is shown in real-time in terms of stability, position tracking performances and robustness with respect to identification errors and external disturbances.     

Reaeration Equations Derived from U.S. Geological Survey Database

Accurate estimation of the reaeration-rate coefficient (K2) is extremely important for waste-load allocation. Currently, available K2 estimation equations generally yield poor estimates when applied to stream conditions different from those for which the equations were derived because they were derived from small databases composed of potentially highly inaccurate measurements. A large data set of K2 measurements made with tracer-gas methods was compiled from U.S. Geological Survey studies. This compilation included 493 reaches on 166 streams in 23 states. Careful screening to detect and eliminate erroneous measurements reduced the data set to 371 measurements. These measurements were divided into four subgroups on the basis of flow regime (channel control or pool and riffle) and stream scale (discharge greater than or less than 0.556 m3∕s). Multiple linear regression in logarithms was applied to relate K2 to 12 stream hydraulic and water-quality characteristics. The resulting best-estimation equations had the form of semiempirical equations that included the rate of energy dissipation and discharge or depth and width as variables. For equation verification, a data set of K2 measurements made with tracer-gas procedures by other agencies was compiled from the literature. This compilation included 127 reaches on at least 24 streams in at least seven states. The standard error of estimate obtained when applying the developed equations to the U.S. Geological Survey data set ranged from 44 to 61%, whereas the standard error of estimate was 78% when applied to the verification data set.     

A Compact 28 GHz Millimeter Wave Antenna for Future Wireless Communication

This article presents a novel modified chuck wagon dinner bell shaped millimeter wave (mm-wave) antenna at 28 GHz. The proposed design has ultra-thin Rogers 5880 substrate with relative permittivity of 2.2. The design consists of T shaped resonating elements and two open ended side stubs. The desired 28 GHz frequency response is achieved by careful parametric modeling of the proposed structure. The maximum achieved single element gain at the desired resonance frequency is 3.45 dBi. The efficiency of the proposed design over the operating band is more than 88%. The impedance bandwidth achieved for −10 dB reference value is nearly 2.9 GHz. The proposed antenna is transformed into four element linear array which increases the gain up to 10.5 dBi. The fabricated prototype is tested for the measured results. It is observed that measured results closely match the simulated results. By considering its simple structure and focused radiation patterns, the proposed design is well suited for IoT (Internet of Things), mmWave microwave sensing, 5G and future RF (Radio Frequency) front-ends.     

On very true operators on pocrims

Hájek introduced the logic enriching the logic BL by a unary connective vt which is a formalization of Zadeh’s fuzzy truth value “very true”. algebras, i.e., BL-algebras with unary operations, called vt-operators, which are among others subdiagonal, are an algebraic counterpart of Partially ordered commutative integral residuated monoids (pocrims) are common generalizations of both BL-algebras and Heyting algebras. The aim of our paper is to introduce and study algebraic properties of pocrims endowed by “very-true” and “very-false”-like operators. Research is supported by the Research and Development Council of Czech Government via project MSN 6198959214.     

Effects of lamination and changes in layer thickness on fatigue-crack propagation of lightweight laminated metal composites

The effects of lamination and changes in the laminae thickness on the fatigue-crack propagation of 6090/SiC/25p-6013 laminates tested in the crack-arrestor orientation were investigated. The fatigue-crack propagation behavior of the individual monolithic and discontinuously reinforced aluminum alloy (DRA) layers was compared to that of the laminates. The fatigue behavior of the laminates was different than that of the individual laminae and was affected by changes in the layer thickness. In-situ monitoring of fatigue-crack growth and postmortem analyses were used to determine the likely source(s) of the layer-thickness effect and differences between the laminated metal composites (LMCs) and its constituents.