4,426 research outputs found
Cloud Computing in VANETs: Architecture, Taxonomy, and Challenges
Cloud Computing in VANETs (CC-V) has been investigated into two major themes of research including Vehicular Cloud Computing (VCC) and Vehicle using Cloud (VuC). VCC is the realization of autonomous cloud among vehicles to share their abundant resources. VuC is the efficient usage of conventional cloud by on-road vehicles via a reliable Internet connection. Recently, number of advancements have been made to address the issues and challenges in VCC and VuC. This paper qualitatively reviews CC-V with the emphasis on layered architecture, network component, taxonomy, and future challenges. Specifically, a four-layered architecture for CC-V is proposed including perception, co-ordination, artificial intelligence and smart application layers. Three network component of CC-V namely, vehicle, connection and computation are explored with their cooperative roles. A taxonomy for CC-V is presented considering major themes of research in the area including design of architecture, data dissemination, security, and applications. Related literature on each theme are critically investigated with comparative assessment of recent advances. Finally, some open research challenges are identified as future issues. The challenges are the outcome of the critical and qualitative assessment of literature on CC-V
Design of Frequency Reconfigurable Multiband Compact Antenna using two PIN diodes for WLAN/WiMAX Applications
YesIn this paper, we present a simple reconfigurable multiband antenna with two PIN diode switches for WiMAX/WLAN applications. The antenna permits reconfigurable switching in up to ten frequency bands between 2.2 GHz and 6 GHz, with relative impedance bandwidths of around 2.5% and 8%. The proposed antenna has been simulated using CST microwave studio software and fabricated on an FR-4 substrate. It is compact, with an area of 50 × 45 mm2, and has a slotted ground substrate. Both measured and simulated return loss characteristics of the optimized antenna show that it satisfies the requirement of 2.4/5.8 GHz WLAN and 3.5 GHz WiMAX antenna applications. Moreover, there is good agreement between the measured and simulated result in terms of radiation pattern and gain.Engineering and Physical Science Research Council through Grant EP/E022936A
Microstructural design of high performance natural fibre reinforced vinyl-ester eco-nanocomposites
The primary aim of this project was to design cellulose fibre reinforced vinyl-ester resin composites with improved mechanical and thermal properties. The project reports on the fabrication of vinyl ester, eco-composites and eco-nanocomposites and characterises these samples in terms of their water absorption, strength, toughness, and thermal properties. The results confirmed that the addition of nano-fillers enhanced the interfacial bonding, resistance to water diffusion, mechanical properties, and thermal stability
Insecticide resistance in Culex quinquefasciatus from Zanzibar: implications for vector control programmes
Background
Zanzibar has a long history of lymphatic filariasis (LF) caused by the filarial parasite Wuchereria
bancrofti, and transmitted by the mosquito Culex quinquefasciatus Say. The LF Programme in Zanzibar has
successfully implemented mass drug administration (MDA) to interrupt transmission, and is now in the elimination
phase. Monitoring infections in mosquitoes, and assessing the potential role of interventions such as vector control,
is important in case the disease re-emerges as a public health problem. Here, we examine Culex mosquito species
from the two main islands to detect W. bancrofti infection and to determine levels of susceptibility to the insecticides used for vector control.
Methods
Culex mosquitoes collected during routine catches in Vitongoji, Pemba Island, and Makadara, Unguja Island were tested for W. bancrofti infection using PCR. Insecticide bioassays on Culex mosquitoes were performed
to determine susceptibility to permethrin, deltamethrin, lambda-cyhalothrin, DDT and bendiocarb. Additional
synergism assays with piperonyl butoxide (PBO) were used for lambda-cyhalothrin. Pyrosequencing was used to determine the kdr genotype and sequencing of the mitochondrial cytochrome oxidase I (mtCOI) subunit
performed to identify ambiguous Culex species.
Results
None of the wild-caught Culex mosquitoes analysed were found to be positive for W. bancrofti. High frequencies of resistance to all insecticides were found in Wete, Pemba Island, whereas Culex from the nearby site of Tibirinzi (Pemba) and in Kilimani, Unguja Island remained relatively susceptible. Species identification confirmed
that mosquitoes from Wete were Culex quinquefasciatus. The majority of the Culex collected from Tibirinzi and all from Kilimani could not be identified to species by molecular assays. Two alternative kdr alleles, both resulting in a
L1014F substitution were detected in Cx. quinquefasciatus from Wete with no homozygote susceptible detected. Metabolic resistance to pyrethroids was also implicated by PBO synergism assays.
Conclusions
Results from the xenomonitoring are encouraging for the LF programme in Zanzibar. However, the
high levels of pyrethroid resistance found in the principle LF vector in Pemba Island will need to be taken into
consideration if vector control is to be implemented as part of the elimination programme
The Design of a Uniplanar Printed Triple Band-Rejected UWB Antenna using Particle Swarm Optimization and the Firefly Algorithm
YesA compact planar monopole antenna is proposed for ultra-wideband applications. The antenna has a microstrip line feed and band-rejected characteristics and consists of a ring patch and partial ground plane with a defective ground structure of rectangular shape. An annular strip is etched above the radiating element and two slots, one C-shaped and one arc-shaped, are embedded in the radiating patch. The proposed antenna has been optimized using bio-inspired algorithms, namely Particle Swarm Optimization and the Firefly Algorithm, based on a new software algorithm (Antenna Optimizer). Multi-objective optimization achieves rejection bands at 3.3 to 3.7 GHz for WiMAX, 5.15 to 5.825 GHz for the 802.11a WLAN system or HIPERLAN/2, and 7.25 to 7.745 GHz for C-band satellite communication systems. Validated results show wideband performance from 2.7 to 10.6 GHz with S11 ˂ -10 dB. The antenna has compact dimensions of 28 × 30 mm2. The radiation pattern is comparatively stable across the operating band with a relatively stable gain except in the notched bands.This work was supported in part by the United Kingdom Engineering and Physical Science Research Council (EPSRC) under Grant EP/E022936A, TSB UK under grant application KTP008734 and the Iraqi Ministry of Higher Education and Scientific Research
An outbreak of Glasser’s disease from two farms in Malaysia
Haemophilus parasuis is an endemic bacterial pathogen in pig farms worldwide. In this report, we investigated a suspected case of Glasser’s disease in 3-9 weeks old Landrace cross Duroc piglets from two pig farms. The farmers reported the case to the Veterinary Hospital of University Malaysia Kelantan, with the complaint of anorexia, depression and weakness. On physical examination, the piglets were found to be smaller in size and had rough hair coat. Clinical signs included swollen hock joint, labored abdominal breathing and tremors. Post-mortem evaluation of culled moribund piglets showed pneumonic lesions in the lung, polyarthritis of the hock joint, cerebral congestion, meningitis, renal cortical heamorrhage and polyserositis. Histo-pathological examination showed interstitial pneumonia with emphysema, encephalitis, encephalomalacia with gliosis and vacuolar degeneration of the hepatocytes. Bacteriological culture of swab samples from infected organs revealed the growth of satellitic small colonies on blood culture suggestive of H. parasuis. Ceftiofur injection (HIPRA, Malaysia, 3mg kg-1i.m), phenoxymethyl penicillin (Norvatis Animal Health, Australia at 200g T-1 of feed) and amoxicillin (Norvatis Animal Health at 15-30g 100L-1 of water) were effective in reducing morbidity and reversing clinical signs. Prompt diagnosis and treatment of Glasser’s disease in pig farms is paramount in order to curtail its menace and prevent serious economic losses
Physical and thermal properties of microwave-dried wood lumber impregnated with phenol formaldehyde resin
In this study, microwave-dried oil palm trunk core lumber was impregnated with phenol formaldehyde resin using high pressure vacuum chamber. The impregnation of oil palm trunk core lumber was performed under 3 bar pressure and cured in an oven at 150°C for 2 h. The impregnation of oil palm trunk core lumber was carried out at different time intervals (15, 30, 60, 90, 120 min) to obtain different density lumber and compared with microwave-dried oil palm trunk core lumber and rubberwood. The physical and thermal properties of microwave-dried oil palm trunk core lumber, impregnated oil palm trunk core lumber and rubberwood were studied. In general, the impregnated oil palm trunk core lumber obtained better physical properties than microwave dried oil palm trunk core lumber but slightly lower than rubberwood. The thermal stability of oil palm trunk core lumber was analyzed by using thermogravimetric analysis and it shows that rubberwood exhibited better thermal stability than impregnated oil palm trunk core lumber
A SIMSCAPE based design of a dual maximum power point tracker of a stand-alone photovoltaic system
This paper presents the simulation of a dual maximum power point tracker (dual-MPPT) and attempt to get the global maximum power point GMPP under partial shading conditions for a solar photovoltaic module using MATLAB SIMSCAPE. Traditional single MPP trackers are less efficient than dual MPP trackers and have greater sensitivity to partial shading. By using dual MPP trackers, one can get several features such as the possibility of connecting two arrays with different string sizes or different solar azimuths or tilts within high efficiency. This paper focuses on making the photovoltaic system work at maximum possible power under partial shading condition by using dual MPP trackers to achieve the convergence toward the global maximum power point GMPP
- …
