Evaluation of copy-move forgery detection: datasets and evaluation metrics

Creating copy-move forgery became even easier using a wide range of software and platforms. Many algorithms have been proposed to solve the problem, but each one of those algorithms has its own drawbacks. Researchers face many challenges in developing copy-move detection algorithms, and in this paper, we focus on two challenges. The first is the benchmark dataset, and the second involves evaluation metrics. In this paper, we investigate the available copy-move datasets and their advantages and disadvantages. In addition, we discuss the different metrics that have been used by researchers to evaluate the copy-move forgery detection (CMFD) algorithms. On that basis, we suggest the standard specifications of the appropriate copy-move dataset and the metrics that should be used to evaluate the detection algorithms. The findings of this paper will help researchers evaluate their algorithms effectively and fairly essential for developing reliable algorithms.     

Total factor productivity growth accounting in the construction industry of Singapore

Total factor productivity (TFP) determines long‐term economic growth and is a comprehensive industry‐level productivity measure. This paper proposes Jorgenson's method as an appropriate TFP measurement for the construction industry. The method is less restrictive than the conventional Chau's approach, as it does not impose the Hick Neutral Technical Change assumption. Jorgenson's method is then applied to estimate TFP growth in the construction industry of Singapore over 1984–1998. TFP growth is found down by 1.53% per annum over this period, indicating that the performance of TFP in the construction industry lags behind the rest of economy. TFP growth is also found to be fluctuating over time and tends to move in tandem with the construction business cycle.

As a monitor of progress towards TFP achievement, factors influencing TFP growth in the construction industry of Singapore over 1984–1997 are identified. Seven factors are found to be significantly related to TFP growth. Among them, economies of scale, R&D by the industry, investment allowance granted and labour unions are leading contributors to TFP growth; while foreign worker, construction accidents and pre‐cast are major hampers.

The general methodology presented in this study can be applied to other countries. Future studies are required to find appropriate indicators for factors unquantified.     

Investigation on the effect of spinning conditions on the properties of hollow fiber membrane for hemodialysis application

Polyethersulfone (PES) hollow fiber membranes were fabricated via the dry‐wet phase inversion spinning technique, aiming to produce an asymmetric, micro porous ultrafiltration hollow‐fiber specifically for hemodialysis membrane. The objective of this study is to investigate the effect of spinning conditions on the morphological and permeation properties of the fabricated membrane. Among the parameters that were studied in this work are air gap distance, dope extrusion rate, bore fluid flow rate, and the take‐up speed. The contact angle was measured to determine the hydrophilicity of the fibers. Membrane with sufficient hydrophilicity properties is desired for hemodialysis application to avoid fouling and increase its biocompatibility. The influences of the hollow fiber's morphology (i.e., diameter and wall thickness) on the performance of the membranes were evaluated by pure water flux and BSA rejection. The experimental results showed that the dope extrusion rate to bore fluid flow rate ratio should be maintained at 1:1 ratio to produce a perfectly rounded asymmetric hollow fiber membrane. Moreover, the flux of the hollow fiber spun at higher air gap distance had better flux than the one spun at lower air gap distance. Furthermore, spinning asymmetric hollow fiber membranes at high air gap distance helps to produce a thin and porous skin layer, leading to a better flux but a relatively low percentage of rejection for BSA separation. Findings from this study would serve as primary data which will be a useful guide for fabricating a high performance hemodialysis hollow fiber membrane. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43633.     

NUMERICAL SIMULATION OF FLAME PROPAGATION NEAR EXTINCTION CONDITION IN A MICRO COMBUSTOR

In the present study, a numerical simulation of flame propagation and extinction in a micro combustor that is subject to excessive heat loss to the wall, particularly during flame propagation, is described. Heat loss to the wall was empirically modeled from measurement data on a similarly configured micro combustor. A PISO based numerical scheme was used for differencing the conservation equations. An H₂-air reaction mechanism involving 16 species and 10 reaction steps was used to approximate the combustion process. A cylindrical computation domain was used to simulate the experiments. The combustor volume has a small height to radius ratio and an axial gradient of properties can be significant. In the present study, however, axial gradients were ignored, leaving radius as the only spatial coordinate. Instead of evaluating heat transfer from the temperature gradient near the wall surface, an empirical bulk heat transfer coefficient was used to approximate heat loss to the wall. A comparison of the computation and measurements showed a good agreement in flame propagation speed and cooling process, after the flame had been quenched by an artificially imposed extinction condition.     

The crystallography of the austenite-ferrite/carbide transformation in Fe−Cr−C alloys

This paper establishes the crystallography of the austenite-ferrite/carbide transformation in Cr bearing steels. The crystallographic analysis, based on the use of retained austenite in the martensitic phase, is consistent with the oriented nucleation of ferrite in austenite. Similarly, it is shown that the nature of the carbide dispersion, which precipitates in association with the transformation, is a sensitive function of the exact austenite/ferrite crystallography.     

Carbon molecular sieve membranes derived from pseudo-interpenetrating polymer networks for gas separation and carbon capture

The design of polyimide-based pseudo-interpenetrating polymer networks (IPNs) is proposed to tailor the molecular structure of polymeric precursors for fabricating carbon molecular sieve membranes (CMSMs). To demonstrate the feasibility of this concept, pseudo-IPNs comprising of poly(2,3,5,6-phenylene-2,2′-bis(3,4-carboxylphenyl)hexafluoropropane) diimide (6FDA–TMPDA) and 2,6-bis(4-azidobenzylidene)-4-methylcyclohexanone (azide) are used to fabricate CMSMs. The gas transport properties of CMSMs are dependent on the azide loading and heat treatment temperature. During the pyrolysis, two competing processes of pore evolution from the released gases and molecular transformation are occurring simultaneously. The creation of pores determines the structural morphology of the CMSM at a low pyrolysis temperature of 550 °C while the molecular rearrangement is the governing factor for carbonization at an elevated temperature of 800 °C. The CMSMs prepared at 550 °C display good CO₂/N₂ separation performance. The 6FDA–TMPDA/azide (90–10) CMSM pyrolyzed at 550 °C shows a CO₂ permeability of 9290 ± 170 Barrer and an ideal CO₂/N₂ selectivity of 26.0 ± 0.8. CMSMs with high CO₂/CH₄ selectivity can be fabricated by carbonization at 800 °C. The 6FDA–TMPDA/azide (70–30) CMSM prepared at 800 °C has a CO₂ permeability of 280 ± 7.0 Barrer and CO₂/CH₄ selectivity of 164 ± 6.0. The CMSMs derived from polyimide/azide pseudo-IPNs exhibit potential use in pre- and post-combustion CO₂ capture.     

Simple synthesis of ZnS nanoparticles in alkaline medium

ZnS nanoparticles were successfully synthesized by reflux under an alkaline medium. The nanoparticles were characterized by using X-Ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The optical properties of ZnS nanoparticles were examined by photoluminescence (PL) spectrum. The result shows that the as-synthesized ZnS nanoparticles had a cubic phase. SEM image shows that ZnS nanoparticles are basically in spherical shape and are homogeneous. The particle size was found to be in the range of 18 nm.     

Habituation and sensitization of aggression in bullfrogs (Rana catesbeiana): Testing the dual-process theory of habituation.

The aggressive response of male bullfrogs (Rana catesbeiana) habituates with repeated broadcasts of acoustic stimuli simulating a new territorial neighbor. The effects of stimulus repetition rate and stimulus intensity on bullfrog aggressive responses were tested in a field experiment designed to test the assumptions of a dual-process theory of habituation. Synthetic advertisement calls were broadcast at 2 repetition rates and 2 intensities in a factorial design. Bullfrogs were more aggressive at the higher stimulus intensity at both repetition rates. Aggressive responses habituated more slowly at the higher stimulus intensity and slower repetition rate compared with other treatments. Several biotic and abiotic factors had small or negligible effects on aggressive responses. Although consistent with the operation of 2 opposing processes, habituation and sensitization, the data provide only partial support for the assumptions of dual-process theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microbial profiles of commercial, vacuum-packaged, fresh pork of normal or short storage life

The microbial ecology of fresh vacuum-packed pork cuts during storage at -1.5 degrees C for up to 45 days was examined to characterize rates of microbial growth and pH changes in commercially prepared products of normal storage quality. Pork loins in commercial distribution with odour defects were also studied to determine a possible cause of the defects and avoid future problems. In addition, microbial profiles of pork cuts from two plants were compared, after storage for 25 days at -1.5 degrees C, to identify possible reasons for differences in the storage life of product from the plants. The effects of a change in sanitation procedures on the microbial populations of products stored for 25 days were also studied. With normal product, microbial growth in different packages progressed at different rates, reflecting differences in initial levels of bacterial contamination. All samples in the study reached 8 weeks without apparent organoleptic change and samples carried 5.8+/-1.2 log bacteria cm(-2) (mean+/-S.D.). The flora of loins with the odour defect were predominately lactic acid bacteria (LAB) and carnobacteria, but they contained large fractions of Enterobacteriaceae <35 days after packaging. Aeromonas spp. and Shewanella spp. were likely responsible for the sulfide-putrid smell of these spoiled products, but species of Enterobacteriaceae and lactic acid bacteria could have contributed to spoilage. Comparison of microbial groups present in 16 other cuts, half from each of two commercial plants, which were stored for 25 days at -1.5 degrees C, showed that larger fractions of Enterobacteriaceae were present in samples from the plant having difficulty achieving the desired storage life. Additional bacterial samples from 12 cuts supplied by the latter plant obtained after adoption of an acid sanitizer step in the plant cleaning regimen, and also stored for 25 days at -1.5 degrees C, yielded few Enterobacteriaceae, Aeromonas or Shewanella. Use of an acid sanitizer in plant cleaning may be a means of controlling alkali-tolerant bacteria such as Aeromonas or Shewanella which can contaminate pork cuts and spoil vacuum-packaged product. The fraction of Enterobacteriaceae in bacteria populations on fresh pork stored for 25 days at -1.5 degrees C may be a useful indicator of the effectiveness of plant sanitation.