Source Camera Identification using Non-decimated Wavelet Transform

Source Camera identification of digital images can be performed by matching the sensor pattern noise (SPN) of the images with that of the camera reference signature. This paper presents a non-decimated wavelet based source camera identification method for digital images. The proposed algorithm applies a non-decimated wavelet transform on the input image and split the image into its wavelet sub-bands. The coefficients within the resulting wavelet high frequency sub-bands are filtered to extract the SPN of the image. Cross correlation of the image SPN and the camera reference SPN signature is then used to identify the most likely source device of the image. Experimental results were generated using images of ten cameras to identify the source camera of the images. Results show that the proposed technique generates superior results to that of the state of the art wavelet based source camera identification

Environmentally sustainable toll design for congested road networks with uncertain demand

This article proposes a new road toll-design model for congested road networks with uncertain demand that can be used to create a sustainable urban transportation system. For policy assessment and strategic planning purposes, the proposed model extends traditional congestion pricing models to simultaneously consider congestion and environmental externalities due to vehicular use. Based on analyses of physical and environmental capacity constraints, the boundary conditions under which a road user on a link should pay either a congestion toll or an extra environmental tax are identified. The sustainable toll design model is formulated as a two-stage robust optimization problem. The first-stage problem before the realization of the future travel demand aims to minimize a risk-averse objective by determining the optimal toll. The second stage after the uncertain travel demand has been determined is a scenario-based route choice equilibrium formulation with physical and environmental capacity constraints. A heuristic algorithm that combines the sample average approximation approach and a sensitivity analysisbased method is developed to solve the proposed model. The upper and lower bounds of the model solution are also estimated. Two numerical examples are given to show the properties of the proposed model and solution algorithm and to investigate the effects of demand variation and the importance of including risk and environmental taxation in toll design formulations. © Taylor & Francis Group, LLC.postprin

In-line monitoring of mixing performance for smart processes in tubular reactors

This work is focused on the experimental analysis of the fluid dynamics characteristics of a tubular reactor equipped with Kenics static mixers working under turbulent flow con-ditions, with the specific aim of demonstrating the advantages of in-line monitoring tools for continuous process applications. Electrical Resistance Tomography, pressure trans-ducers and Particle Image Velocimetry are employed to evaluate the mixing performance, the pressure drop and the flow field, respectively, considering the standard configuration of the mixers, consisting in mixing elements with alternating orientation, a single mixing element or multiple elements with the same orientation. The applicability of Electrical Resistance Tomography for offering insight into continuous reactors is assessed and the potential of monitoring the mixing performance inside the static mixers is shown. The experimental data suggest that alternatives to the standard element configurations might be adopted for optimizing the fluid mixing process, taking into account the mixing per-formances and the pressure drop, for which a novel correlation based on distributed and concentrated contributions is proposed

Induced defense and its cost in two bryophyte species

Premise: Current knowledge about defense strategies in plants under herbivore pressure is predominantly based on vascular plants. Bryophytes are rarely consumed by herbivores since they have ample secondary metabolites. However, it is unknown whether bryophytes have induced defenses against herbivory and whether there is a trade-off between growth and defense in bryophytes. Methods: In an experiment with two peatland bryophytes, Sphagnum magellanicum Brid. and S. fuscum (Schimp.) H. Klinggr., two kinds of herbivory, clipping with scissors and grazing by mealworms (Tenebrio molitor L.) were simulated. At the end of the experiment, we measured growth traits, carbon-based defense compounds (total phenolics and cellulose) and storage compounds (total nonstructural carbohydrates) of these two Sphagnum species. Results: Grazing but not clipping increased total phenolics and C:N ratio and reduced biomass production and height increment. A negative relationship between biomass production and total phenolics was found in S. magellanicum but not in S. fuscum, indicating a growth–defense trade-off that is species-specific. Grazing reduced the sugar starch content of S. magellanicum and the sugar of S. fuscum. Either clipping or grazing had no effect on chlorophyll fluorescence (including actual and maximum photochemical efficiency of photosystem II) except that a significant effect of clipping on actual photochemical efficiency in S. fuscum was observed. Conclusions: Our results suggest that Sphagnum can have induced defense against herbivory and that this defense can come at a cost of growth. These findings advance our knowledge about induced defense in bryophytes, the earliest land plants

Diuretic Activity of Trianthema portulacastrum Crude Extract in Albino Rats

Purpose: To evaluate the diuretic effect and acute toxicity of the crude aqueous extract of Trianthema portulacastrum in a rat model.Method: Albino rats were divided into five groups. Control group received normal saline (10 mg/kg), reference group received furosemide (10 mg/kg) and test groups were given different doses of crude extract (10, 30 and 50 mg/kg) by intraperitoneal route. Urine was collected and the total volume of urine excreted was expressed as ml/6 hr/100 g body weight. Diuretic index and Lipschitz values were also calculated to make comparison with normal saline and furosemide treated groups, respectively.Results: Significant diuretic (p < 0.001), kaliuretic (p < 0.001) and natriuretic (p < 0.001) effects were observed in treated groups in a dose-dependent manner. Urinary pH remained mostly unchanged during the course of the study. Diuretic index showed good diuretic activity of the crude extract. Lipschitz values indicated that the crude extract at the dose of 50 mg/kg exhibited 79 % diuretic activity compared with that of the reference, furosemide. No lethal effects were observed among albino mice even at the high dose of 3000 mg/kg.Conclusion: The extract of Trianthema portulacastrum, particularly, at the dose of 50 mg/kg significantly increased the urinary volume and concentration of urinary electrolytes with no signs of toxicity and therefore, is a potential diuretic. Further studies, however, are required to isolate the active constituents.Keywords: Trianthema portulacastrum, Saliuretic, Natriuretic, Lipschitz value, Diuretic index, Na+/K+ ratio

Security Scenario Generator (SecGen): A Framework for Generating Randomly Vulnerable Rich-scenario VMs for Learning Computer Security and Hosting CTF Events

Computer security students benefit from hands-on experience applying security tools and techniques to attack and defend vulnerable systems. Virtual machines (VMs) provide an effective way of sharing targets for hacking. However, developing these hacking challenges is time consuming, and once created, essentially static. That is, once the challenge has been "solved" there is no remaining challenge for the student, and if the challenge is created for a competition or assessment, the challenge cannot be reused without risking plagiarism, and collusion. Security Scenario Generator (SecGen) can build complex VMs based on randomised scenarios, with a number of diverse use-cases, including: building networks of VMs with randomised services and in-thewild vulnerabilities and with themed content, which can form the basis of penetration testing activities; VMs for educational lab use; and VMs with randomised CTF challenges. SecGen has a modular architecture which can dynamically generate challenges by nesting modules, and a hints generation system, which is designed to provide scaffolding for novice security students to make progress on complex challenges. SecGen has been used for teaching at universities, and hosting a recent UK-wide CTF event