Safety-modelling on neural networks

Safety modelling of fault-tolerant hardware is as important as reliability modelling for some applications. Neural networks are employed in this paper to realize the safety model of a Duplex system under design. The failure rate which is adequate for the desired safety of the hardware, is acquired from the neural weights at convergence.     

TOPMODEL for Streamflow Simulation of a Tropical Catchment Using Different Resolutions of ASTER DEM: Optimization Through Response Surface Methodology

The unavailability of proper hydrological data quality combined with the complexity of most physical based hydrologic models limits research on rainfall-runoff relationships, particularly in the tropics. In this paper, an attempt has been made to use different resolutions of DEM generated from freely available 30 m-based ASTER imagery as primary input to the topographically-based hydrological (TOPMODEL) model to simulate the runoff of a medium catchment located in the tropics. Response surface methodology (RSM) was applied to optimize the most sensitive parameters for streamflow simulation. DEM resolutions from 30 to 300 m have been used to assess their effects on the topographic index distribution (TI) and TOPMODEL simulation. It is found that changing DEM resolutions reduces the TOPMODEL simulation performance as the resolutions are varied from 30 to 300 m. The study concluded that the ASTER 30 m DEM can be used for reasonable streamflow simulation of a data scarce tropical catchment compared with the resampled DEMs.     

Radiation doses from some common paediatric X-ray examinations in Sudan

Radiation doses to patients from some common paediatric X-ray examinations were studied in three hospitals in Khartoum state, Sudan. Entrance surface dose (ESD) was determined from exposure settings using DosCal software. Totally, 459 patients were included in this study. Mean ESDs obtained from anteroposterior projection for chest, skull, abdomen and pelvis for neonates falls in the range of 52-100, 115-169, 145-183, 204-242 microGy, respectively. For a 1-y-old infant, mean ESD range was 80-114, 153-202, 204-209, 181-264 microGy, respectively. Some doses for neonates and infants were exceeding the reference doses by >20%. The results highlighted that a good technique has to adhere to guidelines necessarily. As demonstrated elsewhere, patients' doses were high in departments using single-phase generators compared with those using constant potential. The results presented will serve as a baseline data needed for deriving reference doses for paediatric X-ray examinations in Sudan.     

A survey on content awareness challenges in IPTV delivery networks

Multimedia Tools and Applications - Nowadays, with the evolution of digital video broadcasting, as well as, the advent of high speed broadband networks, a new era of TV services has emerged known...     

HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY DETERMINATION OF ANILINES WITH FLUORESCENT DETECTION AND PRE-COLUMN DERIVATIZATION

A simple, sensitive, and rapid reverse-phase high-performance liquid chromatography (RP-HPLC) method for the determination of anilines in water is proposed. The use of 2,7-diethylamino-2-oxo-2H-chromen-3-yl-benzothiazole-6-sulfonylchloride (coumarin 6-SO₂Cl) as a fluorigenic-labeling reagent was investigated. The label reacted with aniline within 30 min under mild conditions (ambient temperature, pH 9.0) to give sulfonamides that were separated by RP-HPLC employing fluorescence detection with an excitation wavelength of 470 nm and an emission wavelength of 520 nm. The optimum conditions for fluorescence, derivatization, and chromatographic separation were established. The calibration curves were linear for the range 0–800 ppb. The proposed method was applied for the determination of anilines in spiked drinking water samples and irrigation water samples with recoveries of 90.0–103.9% and relative standard deviations of 1.2–4.7%, respectively. This method showed good accuracy and repeatability that can be used for the quantification of aniline in real samples.     

Equipment performance and radiation protection status in X-ray fluoroscopy units in Sudan

The number of fluoroscopy and fluoroscopically guided procedures has been substantially growing in developing countries at the same time advanced and sophisticated equipment are used in some hospitals. However, radiation protection requirements are not necessarily well adopted. In this study nine fluoroscopy X-ray units in Sudan were examined for compliance with international standards. The tests included: beam quality, entrance surface air kerma, image quality and radiation field measurements. Staff radiation protection tools such as lead aprons and eye glasses were also visually examined to find out whether international recommendations were fulfilled and to determine the level of staff awareness. The measured peak tube voltage deviation exceeded the recommended tolerance level in 30 % of the measurements. The results of patient doses measurements exceeded the recommended reference dose levels in 43 % of the measurements; however image quality and radiation field generally fulfilled the requirements for most units. The study revealed that a considerable number of fluoroscopy units were not performing according to the international standards and highlights the need of optimisation of radiation protection.     

Preparation of ZnO nanoparticles and nanosheets and their application to dye-sensitized solar cells

ZnO nanoparticles which have diameter of 15 nm were prepared by hydrothermal method. ZnO nanosheets were obtained by re-hydrothermal treatment of ZnO nanoparticles. The phase and morphology were investigated by using transmission electron microscope, scanning electron microscope and X-ray diffraction. Also, absorbance spectra were measured by using a UV–vis spectrophotometer. A fill factor of 0.55, short-circuit current of 2.059 mA/cm², open-circuit voltage of 0.593 V and an overall light to electricity conversion efficiency of 1.55% for the solar cell based on ZnO nanosheets were obtained.     

Fabrication and characterization of 3D printable nanocomposite filament based on cellulose nanocrystals and polylactic acid using ionic liquids

Nanocellulose, which is biodegradable and possesses excellent physicochemical properties, has high potential in many applications. However, its intrinsic hydrophilic nature makes it difficult to be used as fillers in most hydrophobic polymer composites. Here, cellulose nanocrystals (CNCs) were successfully prepared using 1-hexly-3-methylimidazolium hydrogen sulfate [Hmim][HSO₄] ionic liquid under optimized conditions at 71°C, ultra-sonication amplitude of 69%, and ultrasonication time of 23 min. The prepared CNCs were surface-modified using 1-butyl-3-methylimidazolium tetrafluoroborate [Bmim][BF₄]. A 3D printable nanocomposite filament containing CNCs embedded in polylactic acid was fabricated via extrusion process at 170°C. The prepared filaments were characterized using universal testing machine, field emission scanning electron microscopy, thermogravimetric analysis, and FTIR. It was shown that CNCs had a diameter and length of 10–24 and 60–400 nm, respectively. It was also found that incorporating 2 wt% of CNCs into the matrix phase increased filaments tensile strength by 2.5% (from 54.59 to 57.35 MPa) due to the plasticization effect of [Bmim][BF₄]. The prepared composites exhibited lower activation energies compared to neat PLA due to the small traces of sulfate group on F-CNC. The mechanical attributes of CNCs/PLA nanocomposites were retained at values comparable to that of fresh PLA and were demonstrated to be 3D printable.     

Reducing verification effort in component-based software engineering through built-in testing

Today component- and service-based technologies play a central role in many aspects of enterprise computing. However, although the technologies used to define, implement, and assemble components have improved significantly over recent years, techniques for verifying systems created from them have changed very little. The correctness and reliability of component-based systems are still usually checked using the traditional testing techniques that were in use before components and services became widespread, and the associated costs and overheads still remain high. This paper presents an approach that addresses this problem by making the system verification process more component-oriented. Based on the notion of built-in tests (BIT)—tests that are packaged and distributed with prefabricated, off-the-shelf components—the approach partially automates the testing process, thereby reducing the level of effort needed to establish the acceptability of the system. The approach consists of a method that defines how components should be written to support and make use of run-time tests, and a resource-aware infrastructure that arranges for tests to be executed when they have a minimal impact on the delivery of system services. After providing an introduction to the principles behind component-based verification and explaining the main features of the approach and its supporting infrastructure, we show by means of a case study how it can reduce system verification effort.