Distributed composition of complex event services in IoT network

The Journal of Supercomputing - In this paper, a distributed solution is presented for the composition of complex event services in the Internet of Things (IoT) environments. The composition of...     

A research on sintering characteristics and mechanisms of dried sewage sludge

This study investigates the sintering behavior of dried sewage sludge and the related sintering mechanisms, considering sintering temperature and sintering time. Experimental results indicate that the characteristics are primarily influenced by sintering temperature. When the sintering temperature is increased from 1020 to 1050 °C, the specimens’ compressive strength and bulk density increase significantly, while water absorption decreases obviously, indicating an improvement of densification due to sintering. However, the compressive strength cannot meet the requirement for traditional ceramic products due to the release of organic matters and the formation of big pores in the products. Phosphorus in sewage sludge initially takes reactions with the formation of calcium magnesium phosphate and aluminum phosphate during sintering, which are helpful for enhancing the compressive strength. So, some materials with high contents of Al could be used to enhance the compressive strength of products. Heavy metals are fixed primarily inside the sintered specimens, with the As, Pb, Cd, Cr, Ni, Cu, Zn concentrations in the leachate found to be in the range of China regulatory requirements. These results reveal the feasibility of recycling dried sewage sludge by sintering as a construction material.     

The Investigation of the Fractional-View Dynamics of Helmholtz Equations Within Caputo Operator

It is eminent that partial differential equations are extensively meaningful in physics, mathematics and engineering. Natural phenomena are formulated with partial differential equations and are solved analytically or numerically to interrogate the system’s dynamical behavior. In the present research, mathematical modeling is extended and the modeling solutions Helmholtz equations are discussed in the fractional view of derivatives. First, the Helmholtz equations are presented in Caputo’s fractional derivative. Then Natural transformation, along with the decomposition method, is used to attain the series form solutions of the suggested problems. For justification of the proposed technique, it is applied to several numerical examples. The graphical representation of the solutions shows that the suggested technique is an accurate and effective technique with a high convergence rate than other methods. The less calculation and higher rate of convergence have confirmed the present technique’s reliability and applicability to solve partial differential equations and their systems in a fractional framework.     

An Approximate Analysis of Buffered S-ALOHA in Fading Channels Using Tagged User Analysis

Tagged user analysis (TUA) is a generic approximate method of analyzing random access protocols for finite-user finite-buffer systems. This technique decouples the channel contention behavior from the user queuing behavior and allows the use of classical queuing theory results to be directly applicable to the analysis of finite-user finite-buffer random access methods. In this paper, we extend TUA to analyze finite buffer S-ALOHA operating over flat fading radio channels and derive expressions for system performance indices like throughput, average packet delay, blocking probability and queue length. It is shown that for a moderate number of active users, the simulation and analytical results fit closely     

Analysis of spatially distributed FU-FB S-ALOHA in fading channels using TUA

The tagged user analysis (TUA) is a generic approximate method developed to analyze random access protocols for finite-user finite-buffer systems that avoids complexities of Markovian analysis by using available queueing results. In this paper, TUA method is extended to the analysis of finite buffer S-ALOHA operating over flat fading radio channels when the user population is spatially distributed. The expressions for system performance indices are derived. It is shown that for moderate number of active users, the simulation and analytical results have a close fit.     

A study of spin rectification effect enhancement of microwave field by a PIFA

The progress of spin rectification effect, which has the potential in powering the nanoscopic devices wirelessly, has been impeded by its low conversion efficiency. To solve this problem, a 5.8 GHz planar inverted F‐shaped antenna, which is designed to harvest radiated microwave power as well as foster a field enhanced area surrounding a permalloy (Py, Ni₈₀Fe₂₀) monolayer, is presented. The electric and magnetic field are enhanced by ~17.5‐fold and ~ 45‐fold, respectively. With the proposed antenna, a photovoltage of 0.85 μV can be detected in the monolayer 1.5 m away from the transmitting antenna, with input power of 30 dBm. This work provides an effective method to enhance the spin rectification effect signal in the far field region and paves the way for spintronic devices to be potentially utilized in practical wireless applications, such as quantum information, photovoltaics, and nanogenerator.     

Bioimpedance sensor to detect water content in milk based on van Der Pauw method

Milk fraud poses serious problems for the dairy industry and consumers'' health. The main aim of this study was to reveal the effect of water added to milk by measuring its electrical impedance spectrum. The required sensor was designed based on the van der Pauw method to measure the electrical conductivity of milk at the frequency band of 10 Hz to 5 MHz. The bioimpedance spectrum of the milk of five different cows showed that the electrical impedance spectrum has a high potential for detecting water added to the milk (P < 0.01). The area under the Nyquist curve was introduced as a suitable index to detect water‐added milk. In addition, the characteristic frequency of the bioimpedance spectrum was used as an important index to differentiate water‐added milk from waterless milk. An electrical model was introduced to interpret the amount of water added to the milk using the characteristic frequency. Results showed that it is possible to detect raw milk from boiled milk by measuring its electrical impedance.     

Image-driven virtual simulation of arthroscopy

In recent years, minimally invasive arthroscopic surgery has replaced a number of conventional open orthopedic surgery procedures on joints. While this achieves a number of advantages for the patient, the surgeons have to learn very different skills, since the surgery is performed with special miniature pencil-like tools and cameras inserted through little incisions while observing the surgical field on video monitor. Therefore, virtual reality simulation becomes an alternative to traditional surgical training based on hundreds years old apprentice–master model that involves either real patients or increasingly difficult to procure cadavers. Normally, 3D simulation of the virtual surgical field requires significant efforts from the software developers but yet remains not always photorealistic. In contrast to this, for photorealistic visualization and haptic interaction with the surgical field we propose to use real arthroscopic images augmented with 3D object models. The proposed technique allows for feeling the joint cavity displayed on video monitor as real 3D objects rather than their images while various surgical procedures, such as menisectomy, are simulated in real time. In the preprocessing stage of the proposed approach, the arthroscopic images are stitched into panoramas and augmented with implicitly defined object models representing deformable menisci. In the simulation loop, depth information from the mixed scene is used for haptic rendering. The scene depth map and visual display are reevaluated only when the scene is modified.     

A nonlinear quantization scheme for two-layer HDR image encoding

Two-layer schemes provide an effective method of encoding high dynamic range images with backward compatibility. The first layer is the tone-mapped low dynamic range version of the original image, used for visualization. The residual information that cannot be preserved in the first layer is stored in the second layer, which itself is generally encoded as an image of a fixed bit-depth. Any further details that cannot be preserved in the second layer are discarded. In this paper, we present a nonlinear quantization algorithm that can significantly enhance the amount of details that can be preserved in the second layer, and therefore improve the encoding efficiency. The proposed technique can be incorporated in any existing two-layer encoding method and leads to significant improvement in their performance.     

Structural and Mechanical Properties of Al/B4C Composites Fabricated by Wet Attrition Milling and Hot Extrusion

In this study,Al matrix composites reinforced by 7.5 and 15 vol.%B₄C particles and also monolithic Al（Al without the B₄C particles） were produced by wet attrition milling and subsequent hot forward extrusion processes.The microstructure of the composites,evaluated by scanning electron microscopy（SEM）,showed that the B₄C particles were properly distributed in the Al matrix.Mechanical properties of the AI/B₄C composites and monolithic Al were investigated by tensile,wear and hardness tests.The results revealed that with increasing content of B₄C particles,the tensile strength and microhardness of composites increased but the elongation decreased.In addition,the tensile strength and microhardness of composite samples were higher than those of monolithic Al.The density measurements revealed that the density of composites decreased with increasing content of the B₄C particles.