A localization algorithm for large scale mobile wireless sensor networks: a learning approach

Localization is a crucial problem in wireless sensor networks and most of the localization algorithms given in the literature are non-adaptive and designed for fixed sensor networks. In this paper, we propose a learning based localization algorithm for mobile wireless sensor networks. By this technique, mobility in the network will be discovered by two crucial methods in the beacons: position and distance checks methods. These two methods help to have accurate localization and constrain communication just when it is necessary. The proposed method localizes the nodes based on connectivity information (hop count), which doesn’t need extra hardware and is cost efficient. The experimental results show that the proposed algorithm is scalable with a small set of beacons in large scale network with a high density of nodes. The given algorithm is fast and free from a pre-deployment requirement. The simulation results show the high performance of the proposed algorithm.     

A trust-based service suggestion system using human plausible reasoning

Nowadays, there is a growing need to manage trust in open systems as they may contain untrustworthy service providers. Agent Trust Management (ATM) tries to address the problem of finding a set of the most trusted agents in multi agent systems. This paper presents ScubAA, a novel generic ATM framework based on the theory of Human Plausible Reasoning (HPR). For each user’s request, ScubAA determines a ranked list of the most trusted service agents, within the context of the request, and forwards the request to those trusted services only. ScubAA determines an agent’s degree of trust in terms of a single personalized value derived from several types of evidences such as user’s feedback, history of user’s interactions, context of the submitted request, references from third party users as well as from third party service agents, and structure of the society of agents. ScubAA is able to utilize more trust evidences towards a more accurate value of trust. We also propose a function to figure out how similar two users are in a given context. We apply the proposed HPR-based ATM framework to the domain of Web search. The resulting ATM system recommends to the user a list of the most trusted search engines ranked according to the retrieval precision of documents returned in response to the user’s query as well as the degree of trust of the search engines have gained by interacting with other related users within the context of the query. In addition, we conduct a statistical analysis of ScubAA based on ANOVA and by using a data set of forty queries in different domains. This analysis clearly reveals that ScubAA is able to successfully assess the trustworthiness of service agents.     

Activating pulp toward acetylation by chemical or mechanical means

Activation of pulps during acetylation, by prior mechanical or chemical treatment, has been investigated. The effect of degree of beating on the acetylation rate of wood and bagasse pulps has been studied. It is found that the acetylation rate of pulps increases when the degree of beating of pulps is increased to a definite degree, after which it slows down. The maximum reactivity of bagasse pulp is obtained at 50°SR, while that of wood pulp is observed at 30°SR. The effect of grafting of acrylonitrile onto bagasse and wood pulps on their reactivity during acetylation has been also studied. The results indicate that grafting of acrylonitrile onto pulps has a favorable effect on their acetylation rate. This is dependent on the degree of grafting as well as the origin of pulp fibers. The most suitable method of activation during acetylation reaction is dependent on the origin of the pulp. The reactivity of bagasse pulp during acetylation is influenced more by beating of pulp, prior to the reaction, than by the grafting of acrylonitrile onto pulp. On the other hand, the acetylation reaction of wood pulp is activated by grafting rather than by beating. Also the effect of the activation process, mechanical or chemical, on the strength properties of the paper sheets produced from acetylated pulps has been investigated. Chemical activation of wood pulp prior to acetylation resulted in pulp with slightly higher strength properties than that activated by mechanical means. But, in the case of bagasse pulp, mechanical activation resulted in a pulp with strength superior to that produced by chemical activation.     

Effects of redox-active interlayer anions on the oxygen evolution reactivity of NiFe-layered double hydroxide nanosheets

Nickel-iron layered double hydroxide (NiFe-LDH) nanosheets have shown optimal oxygen evolution reaction (OER) performance; however, the role of the intercalated ions in the OER activity remains unclear. In this work, we show that the activity of the NiFe-LDHs can be tailored by the intercalated anions with different redox potentials. The intercalation of anions with low redox potential (high reducing ability), such as hypophosphites, leads to NiFe-LDHs with low OER overpotential of 240 mV and a small Tafel slope of 36.9 mV/dec, whereas NiFe-LDHs intercalated with anions of high redox potential (low reducing ability), such as fluorion, show a high overpotential of 370 mV and a Tafel slope of 80.8 mV/dec. The OER activity shows a surprising linear correlation with the standard redox potential. Density functional theory calculations and X-ray photoelectron spectroscopy analysis indicate that the intercalated anions alter the electronic structure of metal atoms which exposed at the surface. Anions with low standard redox potential and strong reducing ability transfer more electrons to the hydroxide layers. This increases the electron density of the surface metal sites and stabilizes their high-valence states, whose formation is known as the critical step prior to the OER process.

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3D Target Scale Estimation and Target Feature Separation for Size Preserving Tracking in PTZ Video

To achieve size preserving tracking, in addition to controlling the camera’s pan and tilt motions to keep the object of interest in the camera’s field of view (FOV), the camera’s focal length is adjusted automatically to compensate for the changes in the target’s image size caused by the relative motion between the camera and the target. The estimation accuracy of these changes determines the effectiveness of the resulting zoom control. The existing method of choice for real-time target scale estimation applies structure from motion (SFM) based on the weak perspective projection model. In this paper we propose a target scale estimation algorithm with a linear solution based on the more advanced paraperspective projection model, which improves the accuracy of scale estimation by considering center offset. Another key issue in SFM based algorithms is the separation of target and background features, especially when composite camera (pan/tilt/zoom) and target motions are involved. This paper designs a fast target feature separation/grouping algorithm, the 3D affine shape method. The resulting separation automatically adapts to the target’s 3D geometry and motion and is able to accommodate a large amount of off-plane rotation, which most existing separation/grouping algorithms find difficult to achieve. Experimental results illustrate the effectiveness of the proposed scale estimation and feature separation algorithms in tracking translating and rotating objects with a PTZ camera while preserving their sizes. In comparison with the leading size preserving tracking algorithm described by Tordoff and Murray, our algorithm is able to reduce the cumulative tracking error significantly from 17.4% to 3.3%.     

Intracellular localization of samarium in the lactating mammary gland cells: ultrastructural and microanalytical study

The frequent use of some rare earths in the medical and industrial domains make us worry about their intracellular behavior into the body. Reason for which we have investigated the subcellular localization of one of these elements, the samarium, in the mammary gland of lactating female wistar rats using two very sensitive methods of observation and microanalysis, the transmission electron microscopy and the secondary ion mass spectrometry. The ultrastructural study showed the presence of electron dense deposits in the lactating mammary glandular epithelial cell lysosomes of the samarium-treated rats, but no loaded lysosomes were observed in those of control rats. The microanalytical study allowed both the identification of the chemical species present in those deposits as samarium isotopes ((152) Sm(+)) and the cartography of its distribution. Our results confirm the previous ones showing that lysosomes of the glandular epithelial cells are the site of the intracellular concentration of foreign elements such as gallium. The intralysosomal deposits observed in the mammary glandular cells of the samarium-treated rats are similar in their form and density to those observed with the same element in other varieties of cells, such as liver, bone marrow, and spleen cells. Our ultrastructural and microanalytical results and those obtained in previous studies allow deducing that the intralysosomal deposits are very probably composed of an insoluble samarium phosphate salt.     

Point fingerprint: a new 3-D object representation scheme

This paper proposes a new, efficient surface representation method for surface matching. A feature carrier for a surface point, which is a set of two-dimensional (2-D) contours that are the projections of geodesic circles on the tangent plane, is generated. The carrier is named point fingerprint because its pattern is similar to human fingerprints and plays a role in discriminating surface points. Corresponding points on surfaces from different views are found by comparing their fingerprints. The point fingerprint is able to carry curvature, color, and other information which can improve matching accuracy, and the matching process is faster than 2-D image comparison. A novel candidate point selection method based on the fingerprint irregularity is introduced. Point fingerprint is successfully applied to pose estimation of real range data.     

A new quantum-dot cellular automata full-adder

A novel expandable five-input majority gate for quantum-dot cellular automata and a new full-adder cell are presented. Quantum-dot cellular automata (QCA) is an emerging technology and a possible alternative for semiconductor transistor based technologies. A novel QCA majority-logic gate is proposed. This component is suitable for designing QCA circuits. The gate is simple in structure and powerful in terms of implementing digital functions. By applying these kinds of gates, the hardware requirement for a QCA design can be reduced and circuits can be simpler in level, gate counts and clock phases. In order to verify the functionality of the proposed device, some physical proofs are provided. The proper functionality of the FA is checked by means of computer simulations using QCADesigner tool. Both simulation results and physical relations confirm our claims and its usefulness in designing every digital circuit.     

Effect of chemical environments on palladium phthalocyanine thin film sensors for humidity analysis

Chemiresistors based on palladium phthalocyanine (PdPc) thin films were investigated as humidity sensors. The samples were thermally evaporated onto gold electrodes with a thickness about 100 nm. Optical and electrical characteristics of PdPc thin films were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and electrical measurements. The SEM image demonstrates PdPc (30–60 nm) nanosized particles, and XRD pattern shows that thin films are in α-phase at room temperature. Electrical measurements also confirm that PdPc exhibit semiconducting and photoconducting behaviors, and thermal activation energies of thin films were calculated. After that, the sensitivity and reversibility of devices were investigated on exposure to 20–90% RH in various chemical environments at 293 and 323 K. The response time (35–45 s) and recovery time (75–105 s) of sensors were measured at 293 K with respect to different chemical environments. At last, the stability of devices versus different RH% and chemical environments were tested. The sensors show very good stability on exposure to RH for a period of 2 months but their stability has been reduced in ethanol, acetone, and ammonia environments.     

Recovery of Hydroxytyrosol Rich Extract from Two‐Phase Chemlali Olive Pomace by Chemical Treatment

Abstract: A very simple method is proposed to produce hydroxytyrosol, a commercially unavailable compound with well‐known biological properties which justify a potential commercial application. The 2‐phase Chemlali olive pomace is selected as substrate for chemical treatment. Different conditions of chemical treatment, including concentration of acid and alkaline solutions, time and temperature, were assayed. A high amount of hydroxytyrosol (1360 mg/kg of fresh 2‐phase olive pomace) was obtained using water bath after treatment at 80 °C for 90 min with 1 M of H₃PO₄. However, treatment of 2‐phase Chemlali olive pomace using autoclave apparatus could produce a large amount of hydroxytyrosol (1993.60 and 1515.88 mg/kg of fresh alperujo, 1 M acid and basic catalyst, respectively). By taking into consideration practical and economic aspects, acid‐catalyzed treatment was more effective using autoclave conditions, whereas the alkali catalyzed conditions were not very suitable. This study could provide useful information for industry to produce the potentially bioactive compound. Practical Application: The 2‐phase Chemlali olive pomace is selected as substrate for chemical treatment. Treatment of “alperujo” using water bath or autoclave apparatus was carried out. A high amount of hydroxytyrosol was obtained using autoclave apparatus.