Visual sensor network lifetime maximization by prioritized scheduling of nodes

Visual surveillance of a designated air space can be achieved by a randomly distributed camera sensor network spread over a large area. The location and field of view of each battery operated sensor, after a calibration phase, will be known to a central processing node. To increase the lifetime of the network, the density of distributed sensors could be such that a subset of sensors can cover the required air space. As a sensor dies another sensor should be selected to compensate for the dead one and reestablish the complete coverage. This process should be continued until complete coverage is not achievable by the existing sensors. Thereafter, a graceful degradation of the coverage is desirable.The goal is to elongate the lifetime of the network while maintaining a maximum possible coverage of the designated air space. Since the selection of a subset of sensors for complete coverage of the target area is an NP-complete problem, we present a number of heuristics for this case. The proposed methods are categorized in two groups. In one category, the sensors are prioritized based on their visual and communicative properties and the selection is performed according to the prioritizing function. In the other group, we propose traditional evolutionary and swarm intelligence algorithms. The performance of the proposed methods is evaluated through extensive simulations.     

On‐line system identification of structures using wavelet‐Hilbert transform and sparse component analysis

A new wavelet‐Hilbert transform based sparse component analysis (WHT‐SCA) method is presented for online system identification in indeterminate conditions. The instantaneous phase ratios of output signals are obtained by using a wavelet‐Hilbert transform based filter; and the out‐of‐phase data, that causes errors in identification accuracy, is detected and eliminated. Then, modal parameters of the structure are identified through existing relationships between the dispersion of filtered data in the frequency domain. Subsequently, to demonstrate the capability of the online identification, a new controller is introduced by combining the WHT‐SCA and a semi‐active tuned mass damper (STMD), resulting in creation of smart structures. The performance of the proposed method and controller is investigated through examples. The results demonstrate that, modal parameters of structures are identified accurately even with noise contamination and limited number of sensors. Also, the STMD is effectively robust against any variations in modal parameters of the structure.     

Predicting user click behaviour in search engine advertisements

According to the specific requirements and interests of users, search engines select and display advertisements that match user needs and have higher probability of attracting users’ attention based on their previous search history. New objects such as user, advertisement or query cause a deterioration of precision in targeted advertising due to their lack of history. This article surveys this challenge. In the case of new objects, we first extract similar observed objects to the new object and then we use their history as the history of new object. Similarity between objects is measured based on correlation, which is a relation between user and advertisement when the advertisement is displayed to the user. This method is used for all objects, so it has helped us to accurately select relevant advertisements for users’ queries. In our proposed model, we assume that similar users behave in a similar manner. We find that users with few queries are similar to new users. We will show that correlation between users and advertisements’ keywords is high. Thus, users who pay attention to advertisements’ keywords, click similar advertisements. In addition, users who pay attention to specific brand names might have similar behaviours too.     

Synthesis and Structural Characterization of New Lead(II) Discrete and Infinite Cage-Like Framework: A Precursor to Produce Pure Phase Nano-Sized Lead(II) Oxide

A novel Pb(II) complex, {[Pb₂(tpmba)₂(NO₃)₄]·MeOH} _n (1), was obtained by the reaction of a tripodal ligand, N,N′,N″-tris(pyrid-3-ylmethyl)-1,3,5-benzenetricarboxamide (tpmba), with Pb(NO₃)₂. The structure of complex was determined by X-ray crystallography. The results of structural analysis of the complex reveal that 1 is a M₂L₂ cage-like with a methanol molecule beside the cage. An entirely different structure and topology between 1 and similar complexes indicate that the nature of organic ligands affects the structure of assemblies. The results indicate that the framework of this complex is predominated by the nature of the organic ligand, anions, solvent and geometric need of the metal ions. It was found that the coordination number of Pb^II ions is eight, (PbN₃O₅) has a stereo-chemically active electron lone pair and the coordination sphere is hemi-directed. PbO nanoparticles are obtained by thermolysis of 1 at 180 °C with oleic acid as a surfactant. Scanning electron microscopy shows that the size of the PbO particles is ~30 nm.     

A syntactically informed reordering model for statistical machine translation

Word reordering is one of the challengeable problems of machine translation. It is an important factor of quality and efficiency of machine translation systems. In this paper, we introduce a novel reordering model based on an innovative structure, named, phrasal dependency tree. The phrasal dependency tree is a modern syntactic structure which is based on dependency relationships between contiguous non-syntactic phrases. The proposed model integrates syntactical and statistical information in the context of log-linear model aimed at dealing with the reordering problems. It benefits from phrase dependencies, translation directions (orientations) and translation discontinuity between translated phrases. In comparison with well-known and popular reordering models such as distortion, lexicalised and hierarchical models, the experimental study demonstrates the superiority of our model in terms of translation quality. Performance is evaluated for Persian → English and English → German translation tasks using Tehran parallel corpus and WMT07 benchmarks, respectively. The results report 1.54/1.7 and 1.98/3.01 point improvements over the baseline in terms of BLEU/TER metrics on Persian → English and German → English translation tasks, respectively. On average our model retrieved a significant impact on precision with comparable recall value with respect to the lexicalised and distortion models.     

New design equations for assessment of load carrying capacity of castellated steel beams: a machine learning approach

This paper presents an innovative machine learning approach for the formulation of load carrying capacity of castellated steel beams (CSB). New design equations were developed to predict the load carrying capacity of CSB using linear genetic programming (LGP), and an integrated search algorithm of genetic programming and simulated annealing, called GSA. The load capacity was formulated in terms of the geometrical and mechanical properties of the castellated beams. An extensive trial study was carried out to select the most relevant input variables for the LGP and GSA models. A comprehensive database was gathered from the literature to develop the models. The generalization capabilities of the models were verified via several criteria. The sensitivity of the failure load of CSB to the influencing variables was examined and discussed. The employed machine learning systems were found to be effective methods for evaluating the failure load of CSB. The prediction performance of the optimal LGP model was found to be better than that of the GSA model.     

A new design of substrate integrated waveguide diplexer using complementary split ring resonators

Design method for achieving the acceptable electrical responses (isolation and impedance matching) of a mixer in two‐close frequency with substrate integrated waveguide (SIW) is presented. SIW diplexer with complementary split ring resonators and an open stub is proposed. The SIW loaded diplexer is operated below the cutoff frequency of the equivalent waveguide for SIW; therefore, the size of the structure is compacted. Input and output ports matching are realized in the light of open microstrip stub. The diplexer with optimum dimensions is designed and fabricated. The measurement results verified the design procedures. They also show that operation frequencies are very close together, and also the proposed structure is suitable for long term evolution frequency bands.     

Effect of filler material on local and global behaviour of buckling‐restrained braces

The nonlinear response of buildings has attracted a tremendous amount of attention in recent years. Braces, as lateral force‐resisting elements of a structure, are designed to not only react in the elastic region, but also to exhibit nonlinear response beyond the elastic limit. However, buckling in compression drastically degrades the performance of braces under earthquake loading. Buckling restrained braces (BRBs) have been evolved into very effective systems for severe seismic applications. They prevent buckling in compression through the encasing of core steel into a steel tube and confining infill concrete. The effect of infill material is investigated in this research through the use of experimental tests. Filler material may be concrete, grout or mortar, as well as granular material such as compacted aggregate. Moreover, lightweight concrete or lean concrete may be utilized as filler to reduce the overall structural weight. Furthermore, the need for unbonding material may not arise when sand and gravel mixture is used. Nevertheless, the strength of the aggregate should be such that no buckling or strength deterioration is observed. Parametric studies on BRB characteristics are carried out in this research. Results of cyclic loading tests are then provided for individual cases to characterize the effect of response parameters of BRB assemblages. Copyright © 2009 John Wiley & Sons, Ltd.     

Preparation and preliminary evaluation of [^55Co]（II）vancomycin

Co-55 （t1/2=17.53 h） was produced by 150 uA irradiation of a natural nickel target using 15 MeV protons. It was separated from the irradiated target material by two ion exchange chromatography steps with a radiochemical yield of 〉95% and was used for the preparation of [^55Co]vancomycin （[^55Co]VAN）. Optimization studies were performed using Co-57 due to its longer half-life. Cobalt-57 （t1/2=271.79 d） was produced by irradiation of a natural nickel target with 150 pA current of 22 MeV protons. The 57Co was separated from the irradiated target material using a no-carrier-added method with a radiochemical yield of 〉97%. Both products were controlled for radionuclide and chemical purity. The solutions of [^55Co]VAN were prepared （radiochemical yield〉80%） starting with 55Co acetate and vancomycin at room temperature after 30 min. A precise solid phrase extraction （SPE） method was developed using Si Sep-Pak in order to purify/reconstitute the final formulation for animal studies. [^55Co]VAN showed a radiochemical purity of more than 99%. The resultant specific activity was about 1.15 TBq/mmol. It is proved that the tracer is stable in the final product and in presence of human serum at 37℃ up to 24 h. Biodistribution study of [55Co]VAN in normal rats was undertaken for up to 72 h.     

Interactions between serotypes of dengue highlight epidemiological impact of cross-immunity

Dengue, a mosquito-borne virus of humans, infects over 50 million people annually. Infection with any of the four dengue serotypes induces protective immunity to that serotype, but does not confer long-term protection against infection by other serotypes. The immunological interactions between serotypes are of central importance in understanding epidemiological dynamics and anticipating the impact of dengue vaccines. We analysed a 38-year time series with 12 197 serotyped dengue infections from a hospital in Bangkok, Thailand. Using novel mechanistic models to represent different hypothesized immune interactions between serotypes, we found strong evidence that infection with dengue provides substantial short-term cross-protection against other serotypes (approx. 1–3 years). This is the first quantitative evidence that short-term cross-protection exists since human experimental infection studies performed in the 1950s. These findings will impact strategies for designing dengue vaccine studies, future multi-strain modelling efforts, and our understanding of evolutionary pressures in multi-strain disease systems.