Gallery Templates Research Articles

User gait biometrics in smart ambient applications through wearable accelerometer signals: an analysis of the influence of training setup on recognition accuracy

Gait recognition can exploit the signals from wearables, e.g., the accelerometers embedded in smart devices. At present, this kind of recognition mostly underlies subject verification: the incoming probe is compared only with the templates in the system gallery that belong to the claimed identity. For instance, several proposals tackle the continuous recognition of the device owner to detect possible theft or loss. In this case, assuming a short time between the gallery template acquisition and the probe is reasonable. This work rather investigates the viability of a wider range of applications including identification (comparison with a whole system gallery) in the medium-long term. The first contribution is a procedure for extraction and two-phase selection of the most relevant aggregate features from a gait signal. A model is trained for each identity using Logistic Regression. The second contribution is the experiments investigating the effect of the variability of the gait pattern in time. In particular, the recognition performance is influenced by the benchmark partition into training and testing sets when more acquisition sessions are available, like in the exploited ZJU-gaitacc dataset. When close-in-time acquisition data is only available, the results seem to suggest re-identification (short time among captures) as the most promising application for this kind of recognition. The exclusive use of different dataset sessions for training and testing can rather better highlight the dramatic effect of trait variability on the measured performance. This suggests acquiring enrollment data in more sessions when the intended use is in medium-long term applications of smart ambient intelligence.

A non‐invertible transformation based technique to protect a fingerprint template

AbstractA fingerprint‐based authentication system provides security to the applications of numerous fields and usually stores minutiae information in the database as a template. It has been observed from the literature that the reconstruction of an original fingerprint is possible from minutiae points information; hence the security of the stored template becomes extremely crucial. Cancellable biometric techniques based on non‐invertible transformation protect the stored template. These techniques prevent the reconstruction of original fingerprint data from the compromised template and avoid unauthorized access to the system. In this paper, a technique based on the non‐invertible transformation to protect a fingerprint template is proposed. In the technique, minutiae locations in a fingerprint are transformed by using the minutiae's original locations and orientation information, and a user keyset. A principal component analysis based approach to align the probe and gallery templates of fingerprint images while matching is also proposed. The evaluation of the proposed technique is carried out on seven different fingerprint databases taken from FVC2000, FVC2002, and FVC2004 databases, and its performance is compared with other existing state‐of‐the‐art techniques in the literature. The comparative performance shows that the proposed technique is highly robust and performs exceptionally well compared to other existing techniques.

On view‐invariant gait recognition: a feature selection solution

The authors present an improved feature selection solution for the view-invariant gait recognition problem, based on their previously proposed method called view-invariant feature selector (ViFS), which automatically reconstruct an optimised gallery template from a set of multi-view gallery templates. They improved ViFS by introducing a constraint to make sure that the reconstructed features have the same scale as the original features, thus reducing the number of misclassifications caused by data misalignment. They evaluate the improved ViFS on the CASIA B and OU-ISIR large population datasets by performing a wide range of comparative studies in order to explore and confirm its effectiveness. Evaluation results indicate that the proposed framework is very effective for view-invariant gait recognition tasks.

Adsorption of toluene from aqueous solutions using clay-based nanostructures

ABSTRACTIn this study, porous clay heterostructures (PCH) are synthesized through gallery template approach and characterized using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Nitrogen adsorption–desorption techniques. Batch adsorption studies are conducted to investigate the effect of parameters such as adsorbent dosage, pH, concentration, and contact time on adsorption of toluene by PCH in aqueous solutions. Equilibrium data were fitted to the Langmuir and Freundlich models. Based on the results, by increasing the PCH dosage from 0.5 g/L to 4 g/L, toluene removal is enhanced from 34% to 88.1%.

Synthesis of titania modified silica-pillared clay (SPC) with highly ordered interlayered mesoporous structure for removing toxic metal ion Cr(VI) from aqueous state

Titanium-functionalized silica-pillared clays synthesized through post synthetic route was utilized as adsorbers for the removal of Cr(VI) ions from aqueous solutions under different temperatures and initial concentrations. The starting mesostructured silica-pillared clay is assembled by intragallery ammonia-catalyzed hydrolysis of tetraethoxysilane using cationic surfactant as gallery template, and subsequently, the formed interlayered pore walls were decorated with nano-sized TiO2 particle through organic titanium functionalization process. The kind of structural transformation has been confirmed by X-ray diffraction (XRD), nitrogen adsorption–desorption isotherms, Fourier transform infrared (FT-IR) analysis, UV–vis diffuse reflectance spectroscopy (DRS), elemental analysis (XRF), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Such results indicate that most of the grafted titanium species was combined with Si–OH on the surface of gallery pores. By changing the concentration of organic titanium source during synthesis, the porous structure system is effected. Under suitable conditions, these materials exhibit high adsorption capacity and efficiency. Qualitative estimates of the thermodynamic parameters showed that the overall adsorption process is spontaneous (ΔG°<0) and endothermic (ΔH°>0). The adsorption isotherms of Cr(VI) on titanium-functionalized silica-pillared clay were best fitted by Redlich–Peterson models. Detail results of thermodynamics and kinetics are also presented.

Human eyebrow recognition in the matching-recognizing framework

This paper studies the problem of automatically recognizing human eyebrows using a frontal view. In the matching-recognizing framework for image-based object classification, we design an automatic human eyebrow recognition system via fast template matching and Fourier spectrum distance. Fast template matching is used to locate the target subregion of a gallery template or a pure eyebrow image in a probe original eyebrow image, whereas Fourier spectrum distance is used to determine the final identity of the probe original eyebrow image. We conducted a number of experiments to demonstrate the efficacy of the proposed system and corroborate the validity of eyebrow recognition on the BJUT eyebrow database. Moreover, we also tested the system on the color FERET database. Experimental results show that our approach can be directly applied to face recognition by only replacing eyebrow templates with face templates, and may achieve higher accuracy in eyebrow recognition than in small face recognition. This is a strong argument for eyebrow recognition to replace face recognition as an independent biometric in certain scenarios, especially where relatively large eyebrows can be cropped.

Perturbation-enhanced feature correlation filter for robust iris recognition

Visual pattern of human iris provides rich texture information for personal identification. However, it is challenging to match intra-class iris images with large variations in applications. This study proposes a perturbation-enhanced feature correlation filter (PFCF) for robust iris matching. PFCF is developed based on quad-phase minimum average correlation energy filter, but it has two significant improvements. First, PFCF is performed on Gabor filtered iris images to encode both local and global features. On the one hand, Gabor images can enhance the local details of iris texture. On the other hand, correlation filters describe the regional appearance information and measure the global similarity between iris images efficiently. Secondly, artificially perturbed iris images are generated to model intra-class variations. Also, a set of additional correlation filters are developed accordingly as the gallery templates. The decision is determined by the fusion result of multiple correlation filters. Therefore PFCF not only takes the advantages of Gabor images and correlation filters but also enlarges the amount of enrolled templates for robust iris matching. Extensive experiments on three challenging iris image databases demonstrate that the proposed method outperforms the state-of-the-art methods according to its robustness against deformation, rotation, occlusion, blurring and illumination changes in iris images.

Facile synthesis route to NiO–SiO 2 intercalated clay with ordered porous structure: Intragallery interfacially controlled functionalization using nickel–ammonia complex for deep desulfurization

A facile NiO–SiO 2 mixture intercalated clay with ordered porous structure was assembled via a novel intregallery interfacially controlled functionalization method is successfully established. The starting mesostructured silica-pillared clay is assembled by intragallery ammonia-catalyzed hydrolysis of tetraethoxysilane using cationic surfactant as gallery template, and subsequently, the formed porous clay precursor is combined with nickel–ammonia complex to obtain intragallery interfacially controlled functionalization of nickel oxide. The kind of structural transformation has been confirmed by elemental analyses, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), N 2 adsorption–desorption isotherms, DR UV–vis absorption spectra, temperature-programmed reduction (TPR), X-ray photoelectron spectrometer (XPS) and transmission electron microscopy (TEM). The results elucidate that most of the grafted nickel species was combined with Si–OH on the surface of gallery pores and other was incorporated into tetrahedral sites in the intragallery silica framework. The effect of in situ combined nickel–ammonia complex with porous clay precursor is an essential factor to direct the formation of the intragallery interfacially controlled functionalization. And the porous surface Si–OH takes the role decision for the functionalization process. By changing the concentration of nickel–ammonia complex during synthesis, the porous structure, surface area and scattering domain size is effected. Furthermore, the obtained solid materials exhibit excellent selective adsorption for thiophene from coking benzene. The formation mechanism of intragallery interfacially controlled functionalization is proposed.

Medical biometrics in mobile health monitoring

AbstractThis work investigates the feasibility of ECG‐based identity management in mobile health monitoring applications. A body area network that operates in conjunction with ECG biometric recognition is explored for mobile monitoring of patients, rescuers, pilots, soldiers, or field agents in general. Among the major challenges of this technology is the stability of the signals over the monitoring duration. Time dependency is responsible for ECG destabilization, which becomes a significant issue for reliable monitoring. We propose a novel framework that addresses this inadequacy, by updating a gallery template when feature matching is compromised. In addition, strategies for tackling privacy issues in medical data management are proposed. A protocol level solution is discussed, to deal with the ethical issues of this technology. An automatic way of aggregating and managing personal information is presented, designated to operate on the basis of anonymity. The experimental performance measured over long‐ECG recordings demonstrates promising results. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Synthesis of mesoporous silica-pillared clay by intragallery ammonia-catalyzed hydrolysis of tetraethoxysilane using quaternary ammonium surfactants as gallery templates

Mesoporous silica-pillared montmorillonite (MMT) materials were synthesized by intragallery ammonia-catalyzed hydrolysis tetraethoxysilane (TEOS). The reaction involved hydrolysis and condensation of tetraethoxysilane in the presence of intragallery surfactants templates. Powder X-ray diffraction (XRD), N 2 adsorption–desorption isotherms, scanning electron microscopy (SEM) and Fourier transform infra-red (FT-IR) spectra were employed to characterize the mesoporous silica-pillared montmorillonite. These novel materials exhibited reflections corresponding to a basal spacing of 4.76–5.62 nm, a uniform pore size of 3.75–4.51 nm and large surface areas of 597.2–712.4 m 2/g. And the porous structure and physical properties of silica-pillared montmorillonite derivatives remained stable after heating for 5 h at 700 °C in air. Our results indicate that surfactants play a decisive role in pore formation, because they act as micelle-like template during the hydrolysis of TEOS. These mesoporous silica-pillared montmorillonite materials exhibit excellent catalytic activity and selectivity for coker gas oil cracking reaction in comparison to normal MCM-41 and Al-MCM-41.

Preparation of inorganic–organic pillared montmorillonite using ultrasonic treatment

Montmorillonite (Mt) is a clay mineral with expandable layer structure. Mesoporous pillared montmorillonite can be prepared by introducing gallery templates, such as simple metal cations, quaternary ammonium cations, long chain amines, and hydroxyed inorganic metal ions. In this paper, inorganic–organic pillared montmorillonite intercalated by aluminium and alkyl ammonium chloridize (HDTMA–Cl) was successfully prepared by ultrasonic treatment, and the physicochemical properties of the materials were systematically characterized by XRD, FT-IR, SEM and TEM techniques. The d001 basal spacings and microstructures of Mt–Al–HDTMA were characterized by XRD. The function group, crystal surface morphology, structural and chemical analysis of Mt–Al–HDTMA were measured by FT-IR, SEM, TEM and EDX. The results indicated that ultrasonic method might accelerate the diffusion of the intercalating species, which enhanced the textural properties and the morphologies. The results also suggested that aluminium and HDTMA–Cl reagent entered the interlayer of Mt, and that the crystal structure of the final Mt was preserved.

Encapsulation of chiral Mn(III) salen complexes into aluminium pillared clays: Application as heterogeneous catalysts in the epoxidation of styrene

Two chiral manganese(III) salen complexes bearing different chiral diimine bridges, complexes I and II, were encapsulated into three types of Al-pillared clays (Al-PILCs) by in situ generation of the complexes inside the PILCs; one of the PILCs used was derived from a Wyoming clay (Al-WYO) and the other two were from the same original clay Benavila: (i) Al-BEN, where no surfactant was used in the preparation and (ii) Al-TERG, where a polyalchol, i.e. tergitol was used as surfactant to act as an interlayer gallery template. The Al-pillared clay based materials were characterised by different techniques such as FTIR, UV–vis, AA, XPS, XRD and N 2 adsorption at 77 K. They were screened as heterogeneous catalysts in the epoxidation of styrene using iodosylbenzene or m-chloroperbenzoic acid as oxidants. The encapsulated complexes show, in general, moderate alkene conversion (16–40%), but very poor enantiomeric excesses (ee% = 0–14); nevertheless, for complex I encapsulated into Al-TERG using PhIO as oxidant 14 ee% was obtained, which is higher than the value found for the homogeneous phase reaction run under comparable conditions. Characterisation of the catalyst materials after two run suggests partial collapsing of the clay pillars.

Porous materials from clays by the gallery template approach: synthesis, characterization and adsorption properties

Porous materials were obtained from clays by gallery templated synthesis. The equivalent surface areas of the samples were in the range 600–700 m 2 g −1 and the corresponding microporous volumes were near 0.3 cm 3 g −1. HRTEM confirmed the lack of long-range order of the prepared samples. Low temperature nitrogen adsorption showed textural differences in the samples, namely those arising from the neutral amines of different chain length used in synthesis. The possibility of using such materials as adsorbents of volatile organic compounds, due to their textural and hydrophobic characteristics, was studied by the adsorption of ethanol and methyl ethyl ketone and water for comparison. Their potential use as adsorbents for the purification of methane, e.g., for upgrading natural or landfill gas, was also studied by the determination of the room temperature adsorption isotherms of carbon dioxide, ethane, methane and nitrogen, where high initial selectivity values were obtained for the methane/carbon dioxide separation.

Development of Novel Pillared Clays for the Encapsulation of Inorganic Complexes

Several pillared clays were prepared by using a polyalcohol (ethylene glycol or poly(vinyl alcohol)) or a poly(ethylene oxide) surfactant as an interlayer gallery template and an aluminum oligomer species as the pillaring agent. The use of polyalcohols or nonionic surfactants, such as Tergitol, gave materials which, in general, presented larger basal spacing than those found for the solids prepared by a similar procedure but without additives. The initial positive effect in the expansion of the clay interlayers was not totally retained after calcination of the materials; most probably, at the end, the basal spacing is still ruled by the intercalating aluminum species. The pillared clay with the largest basal spacing and specific surface area was used to encapsulate copper(II) complexes with pentadentate N3O2 Schiff base ligands derived from copper(II) acetylacetonate by in situ synthesis. The characterization made (X-ray diffraction, X-ray photoelectron spectroscopy, FTIR spectroscopy, chemical analysis, and low-temperature N2 adsorption) provided evidence that copper(II) complexes with pentadentate N3O2 Schiff base ligands were efficiently entrapped within the lower dimension pores of the pillared clay and that they interact strongly with the pillared clay matrix.