Energy-Aware WBAN for Health Monitoring Using Critical Data Routing (CDR)

Wireless Personal Communications - Wireless body area network (WBAN) is the subfield of Wireless Sensor Network, employs in the area of monitoring the health of the patient. WBAN is also known as...     

Using UML/MARTE to support performance tuning and stress testing in real-time systems

Real-time embedded systems (RTESs) operating in safety-critical domains have to satisfy strict performance requirements in terms of task deadlines, response time, and CPU usage. Two of the main factors affecting the satisfaction of these requirements are the configuration parameters regulating how the system interacts with hardware devices, and the external events triggering the system tasks. In particular, it is necessary to carefully tune the parameters in order to ensure a satisfactory trade-off between responsiveness and usage of computational resources, and also to stress test the system with worst-case inputs likely to violate the requirements. Performance tuning and stress testing are usually manual, time-consuming, and error-prone processes, because the system parameters and input values range in a large domain, and their impact over performance is hard to predict without executing the system. In this paper, we provide an approach, based on UML/MARTE, to support the generation of system configurations predicted to achieve a satisfactory trade-off between response time and CPU usage, and stress test cases that push the system tasks to violate their deadlines. First, we devise a conceptual model that specifies the abstractions required for analyzing task deadlines, response time, and CPU usage, and provide a mapping between these abstractions and UML/MARTE. Then, we prune the UML/MARTE metamodel to only contain a purpose-specific subset of entities needed to support performance tuning and stress testing. The pruned version is a supertype of UML/MARTE, which ensures that all instances of the pruned metamodel are also instances of UML/MARTE. Finally, we cast the generation of configurations and stress test cases as two constrained optimization problems (COPs) over our conceptual model. The input data for these COPs in automatically generated via a model-to-text (M2T) transformation from models specified in the pruned UML/MARTE metamodel to the Optimization Programming Language. We validate our approach in a safety-critical RTES from the maritime and energy domain, showing that (1) our conceptual model can be applied in an industrial setting with reasonable effort, and (2) the optimization problems effectively identify configurations predicted to minimize response time and CPU usage, and stress test cases that maximize deadline misses. Based on our experience, we highlight challenges and potential issues to be aware of when using UML/MARTE to support performance tuning and stress testing in an industrial context.     

AI-driven streamlined modeling: experiences and lessons learned from multiple domains

Software and Systems Modeling - Model-driven technologies (MD*), considered beneficial through abstraction and automation, have not enjoyed widespread adoption in the industry. In keeping with the...     

Physicochemical and Adhesion Characteristics of High-Density Polyethylene when Treated in a Low-Pressure Plasma under Different Electrodes

The present investigation studys the effects of different electrodes such as copper, nickel, and stainless steel under low-pressure plasma on physicochemical and adhesion characteristics of high-density polyethylene (HDPE). To estimate the extent of surface modification, the surface energies of the polymer surfaces exposed to low-pressure plasmas have been determined by measuring contact angles using two standard test liquids of known surface energies. It is observed that the surface energy and its polar component increase with increasing exposure time, attain a maximum, and then decrease. The increase in surface energy and its polar component is relatively more important when the polymer is exposed under a stainless-steel electrode followed by a nickel and then a copper electrode. The dispersion component of surface energy remains almost unaffected. The surfaces have also been studied by optical microscopy and electron spectroscopy for chemical analysis (ESCA). It is observed that when the HDPE is exposed under these electrodes, single crystals of shish kebab structure form, and the extent of formation of crystals is higher under a stainless-steel electrode followed by nickel and then copper electrodes. Exposure of the polymer under low-pressure plasma has essentially incorporated oxygen functionalities on the polymer surface as detected by ESCA. Furthermore the ESCA studies strongly emphasize that higher incorporation of oxygen functionalities are obtained when the polymer is exposed to low-pressure plasma under a stainless-steel electrode followed by nickel and then copper electrodes. These oxygen functionalities have been transformed into various polar functional groups, which have been attributed to increases in the polar component of surface energy as well as the total surface energy of the polymer. Therefore, the maximum increase in surface energy results in stronger adhesion of the polymer when the polymer is exposed under a stainless-steel electrode rather than nickel and copper electrodes.     

Effect of electron beam radiation on mechanical and electrical properties of poly(ethylene-co-vinyl acetate)

Ethylene-vinyl acetate (EVA) copolymer (12% vinyl acetate content) is subjected to electron beam irradiation using trimethylolpropane trimethacrylate (TMPTMA) as a radiation sensitizer. Mechanical and electrical studies of these irradiated samples show that the strength properties (tensile strength, elongation at break) are increased with radiation dosage up to an optimum radiation dose and sensitizer level above which the properties begin to deteriorate. Crosslinking of the polymer takes place on irradiation which is attributed to an increased gel content with increasing radiation dose. Compared to the original samples both dielectric constant and dielectric loss factor decrease for samples subjected to irradiation.     

Comparison of two size-differentiating air samplers for detecting airborne swine viruses under experimental conditions

Detection and quantification of dilute viral aerosols, as encountered outside animal housing facilities, requires methods that are able to detect small numbers of viruses in large volumes of air. This study compared the performance of two size-differentiating cascade impactors; an Andersen 8-stage (ACI; 28.3 L/min) and a high volume Tisch (TCI; 1,133 L/min) to assess sampling efficiency for detecting porcine reproductive and respiratory syndrome virus (PRRSV) and influenza A virus (IAV). Samples of particles sorted by aerodynamic diameter were analyzed by quantitative polymerase chain reaction (qPCR) and collection efficiency was assessed by particle size. Collection media (minimum essential medium [MEM] and beef extract [BE]), elution technique (active versus passive), and sampling times (10, 20, and 30 min) were variables assessed for the TCI sampler. Extraction efficiency was 35% higher with BE as compared to that of MEM (p = 0.0007); active extraction technique was 19% more efficient than the passive technique (p = 0.03); time of sampling did not significantly affect the amount of virus recovered. The ACI sampler was more efficient in detecting both viruses from small and medium sized airborne particles (≤3 μm) as compared to the TCI sampler (p < 0.001). The latter sampler, however, was more efficient at IAV detection from large airborne particles (>3 μm) (p = 0.0025) indicating the potential of this sampler in detecting the presence of small amounts of viruses in aerosols under field conditions.

© 2017 American Association for Aerosol Research     

New two-CFOA-based floating immittance simulators

This paper presents new topologies for emulating floating immittance functions using three to five passive elements and only two current-feedback operational-amplifiers (CFOAs). The feasibility of using only two CFOAs and two passive components is explored. The proposed topologies can emulate lossy positive and negative inductances and capacitance-, inductance-, resistance-multipliers, and frequency dependent negative and positive conductances. The functionality of the proposed circuits was experimentally verified using the commercially available AD844 CFOA. The experimental results are in excellent agreement with theoretical calculations.     

Tuning the interlaminar shear strength and thermo-mechanical properties of glass fiber composites by incorporation of (3-mercaptopropyl) trimethoxysilane-functionalized carbon black

The incorporation of functionalized nanoscale fillers into traditional glass fiber/unsaturated polyester (GF/UPE) composites provides a more robust mechanical attributes. The current study demonstrates the potential of 3-mercaptopropyl trimethoxysilane (MPTS)-functionalized carbon black (f-CB) for enhancing the thermo-mechanical properties of GF composites. The composites infused with 1, 3 and 5 wt% of pristine and MPTS-functionalized CB were fabricated by hand lay-up and hot press processing. Tensile testing, interlaminar shear strength (ILSS) testing and dynamic mechanical analysis were used to evaluate the performance of nanocomposites. Fourier transform infrared spectroscopy validated the MPTS functionalization of CB. Pristine CB-loaded nanocomposites exhibited marginal improvement in ultimate tensile strength (UTS), ILSS and thermo-mechanical properties. However, with the addition of f-CB, the improvement in all the studied properties was more substantial. The inclusion of 5 wt% f-CB increased the elastic modulus and UTS by 16 and 22%, respectively, whereas the ILSS was enhanced by 36%, in comparison to the neat GF composite. The scanning electron microscope analysis of fractured ILSS samples revealed better fiber-matrix adhesion and compatibility in f-CB-loaded nanocomposites. At the same filler weight percentage, the storage modulus at 25 °C was ~ 19% higher than that of neat composite. The f-CB inclusion resulted in increment of T _g by ~ 13 °C over the T _g of neat GF/UPE composite (~ 109 °C). These improvements were due to the chemical connection of f-CB to the UPE matrix and GF surface. With such improvements in thermal and mechanical properties, these nanocomposites can replace the conventional GF composites with prominent improvements in performance.     

Microwave-assisted sintering and improved dielectric,ferroelectric properties of 0.5[(Ba0.7Ca0.3)TiO3]–0.5[Ba(Zr0.2Ti0.8)O3] lead-free ceramics

0.5[(Ba_0.7Ca_0.3)TiO₃]–0.5[Ba(Zr_0.2Ti_0.8)O₃] lead-free ceramics were synthesised by coprecipitation method and sintered by fast microwave sintering (MWS) and by conventional sintering (CS) at 1200°C. After being sintered with the two different methods, the materials were characterised for structural, microstructural, frequency and temperature-dependent dielectric properties, Raman spectroscopy, and ferroelectric measurements. Results are compared and discussed in the present paper. X-ray diffraction confirms the presence of the tetragonal and rhombohedral phases in the composites sintered by both methods. The ferroelectric to paraelectric transition temperature (Tc) is increased in microwave-sintered composite. Diffuse constant (γ) values show BCT–BZT ceramics to be neither normal ferroelectrics nor relaxor ferroelectrics. Raman spectra confirm phase transition in the ceramic samples. Saturation polarisation (Ps) values are 7.62 and 4.28?µC?cm^?2 and nearly equal remanant polarisation (Pr) values were observed for BCT–BZT composite sintered with MWS and CS, respectively.     

Effect of Aramid Pulp and Lapinas Fiber on the Friction and Wear Behavior of NBR Powder–Modified Phenolic Resin Composite

Short fiber reinforcement plays a definite role in governing the performance of a composite through the improvement of different material properties. The present investigation deals with the effect of aramid pulp and lapinas fiber on the friction and wear characteristics of a composite made from phenolic resin modified by powdered acrylonitrile butadiene rubber (NBR) on a pin-on-disc tribometer. Four composites, containing 10, 20, 30, and 40 wt% of aramid pulp with respect to phenolic resin content, were prepared. Another four composites, containing 50, 100, 200, and 300 wt% of lapinas fiber with respect to phenolic resin content, were also made. It was found that the two different fibers have distinctly different contributions to the friction and wear properties of the composites. It was also found that the incorporation of aramid pulp enhances friction stability of the composites much better than that of lapinas fiber. The change in surface morphology of these composites was studied by scanning electron microscopy (SEM) before and after the friction test. SEM images of friction samples containing aramid pulp corroborated the occurrence of wear through an adhesive wear mechanism, whereas the lapinas fiber–containing composites showed an abrasive wear mechanism.