Region-based surveillance video retrieval with effective object representation

Retrieving the most relevant video frames that contain the object specified in a given query (query-by-region) remains a challenging task. Two common challenges of region-based retrieval approaches are to accurately extract or segment object(s) and select a proper matching strategy. This paper addresses these problems by proposing a retrieval approach that uses a new region-based matching technique equipped with an effective object representation method. In the first stage, the proposed approach selects the most informative instances of each object that appeared in the video by utilizing an adapted clustering algorithm over the extracted features. In the retrieval stage, the new matching technique returns the most relevant sequences of video by mapping a given region with those identified representative instances of objects based on their similarity scores. The proposed approach is evaluated on standard datasets and the results demonstrate a 31% improvement in the retrieval performance compared to other state-of-the-art methods.     

Plasma Internal Inductance in the Presence of External Resonant Fields in IR-T1 Tokamak

In this paper we presented experimental investigation of effects of local limiter biasing (V_biasing = +200 v, V_biasing = +320 v) on the plasma parameters as plasma current, loop voltage, poloidal beta, plasma pressure, plasma energy, plasma resistance, plasma temperature, plasma displacement, Shafranov parameter and plasma internal inductance in IR-T1 tokamak. For these purposes, array of magnetic probes and also a diamagnetic loop have been used. The results show that applied biased voltage V_biasing = +200 v causes to decrease of about 40 % in plasma internal inductance. The plasma resistance and the plasma displacement have been decreased by V_biasing = +200 v. The main result of the application of V_biasing = +200 v is flatting the plasma parameters profiles. In other words, the addition of biasing voltage V_biasing = +200 v to plasma could be effective for improving the quality of tokamak plasma discharge by creating the steady state plasma. The plasma current, plasma pressure, plasma energy, plasma temperature and shift parameter have increased after the application of limiter biasing with V_biasing = +320 v but they decrease rapidly.     

STFT Analysis of the Particle Transport on the IR-T1 Tokamak Plasma Sheath

The time-resolved frequency component analysis has been performed using short time Fourier transform. Fourier-based techniques and auto-correlation have been employed to analyze the frequency of the MHD fluctuations. The time evolution of potential fluctuation, and electric field and turbulent transport have been measured by using two arrays of the Langmuir probes in both the radial and poloidal directions. The experiments have been done in different regimes as Limiter biasing and RHF and both of them. The analyses have been done by the fast Fourier transport (FFT) method and spectral features of them are obtained with the help of the standard auto-correlation technique. The results show that radial turbulent transport decreases about 60 % after positive biasing application while it increases about 40 % after negative biasing. The effect of positive biasing on poloidal turbulent transport displays an increase of about 55 % while the negative bias voltage decreases the poloidal turbulent transport about 30 %. Consequently, confinement is improved and plasma density rises significantly due to the applied positive biasing in IR-T1. But the results are reversed when negative biasing is applied. Also, in this work, the results of applied RHF (L = 3) are compared with biasing results and analysed.     

Plasma Confinement Modification in IR-T1 Tokamak by Velocity Shear Stabilization

E × B velocity shear effects on the plasma confinement were investigated in the IR-T1 tokamak. The investigations have been done at the presence of external applied electric and Resonant Helical magnetic Fields (RHF). In this work, experimental data have been measured by using two arrays of the Langmuir probes in both the radial and poloidal directions. A velocity shear stabilization mechanism has also been proposed to be responsible for an improvement in plasma confinement. The results show that E_r × B drift velocity (V_E×B) reduces about 90 % due to applied biasing and RHF at edge plasma. We have also observed that positive biasing and RHF lead to a significant decrease (>80 %) for radial turbulent transport (Γ_E×B) at edge plasma. In this paper, the electrostatic Reynolds stress (Rs) and the shearing rate γ_E×B have been calculated. We have also compared the Rs and γ_E×B at presence of the biasing and RHF and without biasing and RHF. A good correlation between confinement modifications and E_r × B velocity shear has been found suggesting that confinement enhancement originates at the edge plasma as a consequence of the formation of a particle transport barrier just inside the limiter.     

Mesoporous silica coated gold nanorods: a multifunctional theranostic platform for radiotherapy and X-ray imaging

Journal of Porous Materials - The development of theranostic nanostructures is one of the most advanced branches of pharmaceutical and medical sciences in the world today. Due to the unique...     

The effect of promoters on the CO<Subscript>2</Subscript> reforming activity and coke formation of nanocrystalline Ni/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalysts prepared by microemulsion method

Mesoporous nanocrystalline nickel-alumina promoted catalysts with high surface area were prepared by microemulsion (ME) method and employed in dry reforming of methane reaction. The catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller surface area analysis (BET), temperature programmed reduction (TPR) and temperature programmed oxidation (TPO) techniques. The results showed that the prepared catalysts had high porosity with great surface area and small crystallite size. Among the K₂O, MgO, CaO and BaO promoters, the MgO promoter showed considerable effect on catalytic performance and coke suppression of catalyst.     

Sixty-four years of informetrics research: productivity,impact and collaboration

This paper analyses the information science research field of informetrics to identify publication strategies that have been important for its successful researchers. The study uses a micro-analysis of informetrics researchers from 5,417 informetrics papers published in 7 core informetrics journals during 1948–2012. The most productive informetrics researchers were analysed in terms of productivity, citation impact, and co-authorship. The 30 most productive informetrics researchers of all time span several generations and seem to be usually the primary authors of their research, highly collaborative, affiliated with one institution at a time, and often affiliated with a few core European centres. Their research usually has a high total citation impact but not the highest citation impact per paper. Perhaps surprisingly, the US does not seem to be good at producing highly productive researchers but is successful at producing high impact researchers. Although there are exceptions to all of the patterns found, researchers wishing to have the best chance of being part of the next generation of highly productive informetricians may wish to emulate some of these characteristics.     

CO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>-free hydrogen and carbon nanofibers production by methane decomposition over nickel-alumina catalysts

Nickel catalysts supported on mesoporous nanocrystalline gamma alumina with various nickel loadings were prepared and employed for thermocatalytic decomposition of methane into CO _x -free hydrogen and carbon nanofibers. The prepared catalysts with different nickel contents exhibited mesoporous structure with high surface area in the range of 121.3 to 66.2m²g^?1. Increasing in nickel content decreased the pore volume and increased the crystallite size. The catalytic results revealed that the nickel content and operating temperature both play important roles on the catalytic performance of the prepared catalysts. The results showed that increasing in reaction temperature increased the initial conversion of catalysts and significantly decreased the catalyst lifetime. Scanning electron microscopy (SEM) analysis of the spent catalysts evaluated at different temperatures revealed the formation of intertwined carbon filaments. The results showed that increasing in reaction temperature decreased the diameters of nanofibers and increased the formation of encapsulating carbon.     

An understanding of the electrodeposition process of Al–Mg alloys using an organometallic-based electrolyte

Al–Mg alloys were deposited using a base-electrolyte with the composition Na[AlEt₄] + 2Na[Et₃Al–H–AlEt₃] + 2.5AlEt₃ + 6toluene (where Et = −C₂H₅). Mg was introduced into this electrolyte by employing a pure Mg anode. It was found that initially the amount of Mg in the electrolyte increased with the deposition time but eventually a steady state was reached such that the amount of Mg dissolved at the anode became equal to that deposited at the cathode. Compositional and phase analyses indicated that this state is achieved at a critical Mg/Al ratio that resulted in the formation of the hcp Mg-rich phase. By devising various component electrolytes we have attempted to understand the roles of different compounds in the base-electrolyte and have proposed a scheme for the Al–Mg alloy deposition.