Heuristic Approach for Scheduling Dependent Real-Time Tasks

Reducing energy consumption is a critical issue in the design of battery-powered real time systems to prolong battery life. With dynamic voltage scaling (DVS) processors, energy consumption can be reduced efficiently by making appropriate decisions on the processor speed/voltage during the scheduling of real time tasks. Scheduling decision is usually based on parameters which are assumed to be crisp. However, in many circumstances the values of these parameters are vague. The vagueness of parameters suggests that to develop a fuzzy logic approach to reduce energy consumption by determining the appropriate supply-voltage/speed of the processor provided that timing constraints are guaranteed. Intensive simulated experiments and qualitative comparisons with the most related literature have been conducted in the context of dependent real-time tasks. Experimental results have shown that the proposed fuzzy scheduler saves more energy and creates feasible schedules for real time tasks. It also considers tasks priorities which cause higher system utilization and lower deadline miss time

Octafilar Helical Antenna for Portable UHF-RFID Reader

Octafilar helical antenna (OFHA) is proposed for handheld ultra‐high‐frequency (UHF) radio frequency identification (RFID) reader. The investigated antenna configuration consists of OFHA placed on reader device in the presence of human hand model. The antenna is designed at UHF band centered at 915 MHz. The antenna return loss, axial ratio, gain, co‐polarized and cross‐ polarized field components are calculated using the finite element method (FEM) and compared with that calculated by finite integration technique (FIT) for verification of the simulated results. A comparison between the performance of the quadrifilar helical antenna (QFHA) and the octafiliar helical antenna (OFHA) designed at 915 MHz in the presence of the reader device and human hand model is investigated. The OFHA introduces high gain, high front to back ratio, good axial ratio and omnidirectional coverage

Near-Field Focusing Dielectric Resonator Antenna Array for Fixed RFID Readers

The design of a NF‐ focused DRA phased array antenna is implemented for fixed RFID reader applications at 5.8 GHz. The radiated field is focused in the near‐zone of the array aperture. Numerical investigations on the radiation characteristics of the NF‐ focused array as well as uniform phase array are presented to demonstrate its feasibility for RFID real applications

Single/Dual-Polarized Infrared Rectenna for Solar Energy Harvesting

Single and dual linearly-polarized receiving mode nanoantennas are designed for solar energy harvesting at 28.3 THz. The infrared rectennas are used to harvest the solar energy and converting it to electrical energy.  The proposed infrared rectenna is a thin dipole made of gold and printed on a silicon dioxide substrate. Different shapes of the dipole arms have been investigated for maximum collected energy. The two poles of the dipole have been determined in a rectangular, circular and rhombus shapes. The rectenna dipole is used to concentrate the electromagnetic energy into a small localized area at the inner tips of the gap between the dipole arms. The dimensions of the different dipole shapes are optimized for maximum near electric field intensity at a frequency of 28.3 THz. A Metal Insulator Metal (MIM) diode is incorporated with the nanoantenna dipole to rectify the received energy. The receiving efficiency of the solar energy collector with integrated MIM diode has been investigated. A dual-polarized, four arms, rhombus shaped nanoantenna dipole for solar energy harvesting has been designed and optimized for 28.3 THz applications

Dielectric Resonator Antenna Mounted on Cylindrical Ground Plane for Handheld RFID Reader at 5.8 GHz

Dielectric resonator antenna (DRA) mounted on cylindrical ground plane is investigated for handheld RFID reader applications at 5.8 GHz. The simplicity of the structure makes it practical in terms of cost, space, and ease of fabrication. The radiation characteristics of the antenna in free space and in the presence of a proposed compact reader device model and human hand are calculated. The antenna is circularly polarized and exhibits peak gain of 7.62 dB at 5.8 GHz with high front to back ratio of 15.5 dB. Using the same reader device model, a sequentially feeding 2×2 DRA array mounted on the same cylindrical ground plane is used for RFID reader antenna at 5.8 GHz. The array introduces high gain of 9.36 dB at 5.8 GHz with high front to back ratio of 10.48 dB. The 2×2 DRA array elements exhibit circular polarization over a frequency band of 1.1 GHz. The axial ratio is 1.1 dB at 5.8 GHz. The proposed reader model is simple and has a small size compared with that in the case of planar ground plane. The results are calculated using the finite element method (FEM) and compared with that calculated using the finite integral technique (FIT)

The control of the drugstore beetle, Stegobium paniceum (Coleoptera: Anobiidae) with high and low temperatures

Botanicals; dried plants, roots, stems, leaves, seeds and flowers, have been used from the dawn of history as drugs or spices (Craker, 2007). Botanicals have been used in the health care system to improve blood circulation, reduce chronic fever and cure chronic constipation (Golob et al., 1999; Samy et al., 2008). The drugstore beetle, Stegobium paniceum (L.) (Coleoptera: Anobiidae), is a pest of stored medicinal and aromatic plants and one of the most common insects found in botanical warehouses (Abdelghany et al., 2010). Generally, mortality of each stage increased with an increase of temperature and exposure time. Heat tolerance for different stages from highest to lowest was; young larvae, old larvae, eggs, adult and pupae. The mortality after 7 h, at 42ºC for young larvae, old larvae, eggs, adult and pupae respectively was; 16 ± 5, 31 ± 6, 48 ± 3, 63 ± 8 and 86 ± 2% (mean + SEM). Similarly, the lethal time for 90% mortality (LT>sub>90) at 42ºC was; too low to estimate, 773, 144, 12 and 11 h. The LT90 value for young larvae at 42, 45, 50, 55 and 60ºC was 25, 20, 3.9, 0.18 and 0.08 h respectively. The cold tolerance of different stages at 0ºC from highest to lowest was adult, old larva, young larva, pupa, and egg. The LT90 at 0ºC was 298, 153, 151, 89 and 53 h, respectively. The LT90 value for adults at 5, -5, -10 and -15ºC was 792, 58, 2 and 0.8 h, respectively. The supercooling point of adults, young larvae, old larvae and pupae was -15.2 ± 2ºC, -9.0 ± 0.8ºC, -6.5 ± 0.5ºC, and -4.0 ± 1.4ºC respectively. Heat treatments that control young larvae should control all other stages of S. paniceum. Cold treatments that control adults should control all other stages of S. paniceum. Dried plants stored at 5ºC for 45 days or 42ºC for 30 h and then kept below 18ºC throughout the rest of the year, should remain pest-free without any chemical control. The full paper was submitted to Entomologia Experimentalis et Applicata. Keywords: Anobiidae, Heat, Cold, Supercooling point, Tolerance, Storage, Warehous

Circular Polarized Dielectric Resonator Antenna for Portable RFID Reader Using a Single Feed

A new design of circular polarized elliptical dielectric resonator antenna (DRA) with single feed for handheld radio frequency identification (RFID) reader is presented. The elliptical dielectric resonator antenna with an aspect ratio of 1.5 is used. This design has achieved 66.7 MHz impedance bandwidth (for S11 < ‐10 dB) by using material with dielectric constant material (εr = 12) in conjunction with coaxial probe feed in free space. The DRA models are simulated using two different numerical techniques, the finite element method and the finite integral technique.  The numerical results of the two different computational methods approache are investigated and compared. The results are in good agreement within the desired frequency band, 5.65 GHz – 5.95 GHz. A model for a handheld RFID reader device including the elliptical DRA in the presence of human hand models is, also, investigated. The return loss is <10 dB over the frequency range of 5.49‐  6.967 GHz resulting in frequency bandwidth of 1.47 GHz. A high front to back ratio and gain of 5.726dBi are obtained