Reconfigurable antennas for wireless network security

Large scale proliferation of wireless technology coupled with the increasingly hostile information security landscape is of serious concern as organizations continue to widely adopt wireless networks to access and distribute critical and con dential information. Private users also face more risks than ever as they exchange more and more sensitive information over home and public networks through their ubiquitous wireless-enabled laptops and hand held devices. The fundamental broadcast nature of wireless data transmission aggravates the situation, since unlike wired networks, it introduces multiple avenues for attack and penetration into a network. Though several traditional mechanisms do exist to protect wireless networks against threats, such schemes are a carryover from the traditional wire based systems. Hence vulnerabilities continue to exist, and have been repeatedly demonstrated to be susceptible to failure under di erent circumstances.The resulting uncertainties have led to a signi cant paradigm shift in the design and implementation of wireless security in recent times, among which wireless channel based security schemes have shown the most promise. Channel based security schemes are rooted on the simple fact that a legitimate user and an adversary cannot be physically co-located and hence the underlying multi-path structure corresponding to the two links cannot be the same. However most wireless systems are constrained in terms of bandwidth, power and number of transceivers, which seriously limit the performance of such channel based security implementations. To overcome these limitations, this thesis proposes a new dimension to the channel based security approach by introducing the capabilities of recon gurable antennas. The main objective of this work is to demonstrate that the ability of recon gurable antennas to generate di erent channel realizations that are uncorrelated between di erent modes will lead to signi cant improvements in intrusion detection rates.To this end, two di erent schemes that make use of channels generated by a recon gurable antenna are proposed and evaluated through measurements. The rstscheme is based on associating a channel based ngerprint to the legitimate user to prevent intrusion. The three main components of this scheme are i ) a ngerprint derived from the di erent modes of the antenna, ii ) a metric to compare two ngerprints and iii ) a hypothesis test based on the proposed metric to classify intruders and legitimate transmitters. The second scheme relies on monitoring the statistics of the channels for the legitimate transmitters' links since any intrusion will result in an observable change in the channel's statistics. The problem is posed as a generalized likelihood ratio test (GLRT) which responds to any change in the channel statistics by a large spike in the likelihood ratio's value. The detector's performance is studied as a function of pattern correlation coe cient for both schemes to provide insights on designing appropriate antenna modes for better performance.Moreover this thesis takes a holistic approach to studying the antenna based security schemes. A novel channel modeling approach which combines the cluster channel model and site speci c ray tracer results is proposed and validated to facilitate the analysis of such schemes through simulations without resorting to comprehensive channel measurements. This approach is motivated by the lack of an intuitive and simple channel model to study systems that use recon gurable antennas for any application.Finally the design of a metamaterial based substrate that can help miniaturize antenna arrays and recon gurable antennas is presented. The magnetic permeabilityenhanced metamaterial's capability to miniaturize an antenna's size while maintaining an acceptable level of isolation between elements in an array is experimentallydemonstrated. The bene ts gained in a wireless communication system that uses a patch antenna arrray built on this substrate is quanti ed in terms of mean e ective gain, correlation between the antennas and channel capacity through channel measurements.Despite their capability to signi cantly improve spectral e ciency, the widespread adoption of recon gurable antennas in wireless devices has been hampered by their complexity, cost and size. The work presented in this thesis is therefore intended to serve as a catalyst to the widespread adoption of recon gurable antenna technology by i ) adding value to such antennas by utilizing them for enhancing system security and ii ) providing a mechanism to miniaturize them to facilitate their integration into modern space constrained wireless devices.Ph.D., Electrical Engineering -- Drexel University, 201

Perception of Soundscape in Landscape

Landscape or nature-related design is mostly focused on the visual aspects. As a result of increased urbanization, the exploration of the possibilities of a tranquil environment concerning landscape enhances the positive effect on the quality of the urban population. This can be achieved by understanding and characterizing the sonic environment in such a setting. In connection to the visual landscape aspects, acoustical cognition in terms of perception of the environment is important. In modern scenarios; the concept of soundscape is used to discuss the quality of the environment. In line with this, the chapter reviews the state of the art of literature on various definitions, perceptions, and theories of landscape in conjunction with the theories of the soundscape and classification of soundscape elements. Also, it reviews the soundscape dimension in the landscape through the function of green spaces and its impact on quiet/tranquility in an urban context by understanding the role of natural and manmade landscape elements on sonic perception along with various methods of data collection commonly used for soundscape research

Ethyl 4-(3-hydroxy­phen­yl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexa­hydro­quinoline-3-carboxyl­ate

In the mol­ecular structure of the title compound, C21H25NO4, the dihydro­pyridine ring adopts a flattened boat conformation while the cyclo­hexenone ring is in an envelope conformation. In the crystal structure, mol­ecules are linked into a two-dimensional network parallel to (10) by N—H⋯O and O—H⋯O hydrogen bonds. The network is generated by R 4 4(30) and R 4 4(34) graph-set motifs

Effects of dietary prebiotics, probiotic and synbiotics on performance, caecal bacterial populations and caecal fermentation concentrations of broiler chickens

Background: In view of a worldwide attempt to restrict or ban the use of antibiotics as growth promoters in animal production, probiotics, prebiotics and combinations of both, as synbiotics, have been suggested as potential alternatives. In this study, the effects of a prebiotic (isomalto-oligosaccharides, IMO), a multi-strain probiotic (consisting of 11 Lactobacillus strains), and a combination of these dietary additives as a synbiotic on the performance, caecal bacterial populations and concentrations of caecal volatile fatty acids and non-volatile fatty acids of broiler chickens were evaluated. Results: Supplementation of 1g kg−1 probiotic (PRO); 5 g kg−1 prebiotic IMO (PRE05); 10 g kg−1 prebiotic IMO (PRE10); synbiotic consisting of 1g kg−1 probiotic + 5 g kg−1 prebiotic IMO (SYN05); or synbiotic consisting of 1g kg−1 probiotic + 10 g kg−1 prebiotic IMO (SYN10) significantly (P < 0.05) improved weight gain of broiler chickens at 22–42 and 1–42 days of age, and feed conversion rate from 1 to 21, 22–42 and 1–42 days of age. The supplementation of probiotic (PRO), prebiotics (PRE05 and PRE10) or synbiotics (SYN05 and SYN10) also significantly (P < 0.05) increased the caecal populations of lactobacilli and bifidobacteria, and decreased the caecal Escherichia coli at 21 days of age, and increased the caecal VFA at 21 and 42 days of age. In all parameters studied, synbiotics did not show a two-fold synergistic effect, when compared to those of probiotic or prebiotic alone. Conclusion: The results of the study indicated that prebiotic IMO (5 g kg−1 or 10 g kg−1), probiotic and their combinations as synbiotics were effective in improving the performance of broiler chickens and in increasing the caecal beneficial bacteria and fatty acids

EVALUATION OF ANTI-CANCER ACTIVITY IN METHANOLIC EXTRACT OF ENICOSTEMMA LITTORALE ON DEN INDUCED HEPATOCARCINOGENESIS IN RATS

The present study is aimed at evaluating the chemoprotective effect of Enicostemma littorale in DEN induced hepato-carcinogenesis in Sprague Dawley rats. The preliminary steps involved extraction, phytochemical investigation, HPTLC study and In vitro antioxidant activity using DPPH, ABTS. and Initiation of HCC was done by single i.p injection of DEN at a dose of 200mg/kg. The MEEL received treatment for 90 days after 14 days of development of HCC and continued for entire study period, whereas the other two group given normal saline, 5-flurouracil (20mg/kg ) i.p. The results showed that the injection DEN lead to the development of liver tumors in rats. Significant effect of serum biochemical parameter like SGOT, SGPT, ALP, UREA, TOTAL PROTEIN and tumor marker was observed with depletion of endogenous antioxidants SOD, CAT, GSH, there by leading to higher LPO. The result exhibited that MEEL treatment (Preventive) group offered excellent shielding against HCC and displayed all the parameter in near normal range with a maintained antioxidant enzyme system. The result obtained showed that extracts were found to containing phenols at a concentration of 70.25 mg/g and flavonoids 26.03mg/g. HPTLC Analysis showed presence of Quercetin, Mangiferin, Gallic acid, Catechin and sweroside. In the DPPH, ABTS, FRAP, TRAP radical scavenging assay MEEL has displayed the highest antiradical activity in both assays and was also comparable with the standard qucertein The present study reveal the efficacy of the MEEL to prevent malignancy induced by chemical carcinogen and the phytoconstituents responsible for activity

Texture Features of Proton Density Fat Fraction Maps from Chemical Shift Encoding-Based MRI Predict Paraspinal Muscle Strength

Texture analysis (TA) has shown promise as a surrogate marker for tissue structure, based on conventional and quantitative MRI sequences. Chemical-shift-encoding-based MRI (CSE-MRI)-derived proton density fat fraction (PDFF) of paraspinal muscles has been associated with various medical conditions including lumbar back pain (LBP) and neuromuscular diseases (NMD). Its application has been shown to improve the prediction of paraspinal muscle strength beyond muscle volume. Since mean PDFF values do not fully reflect muscle tissue structure, the purpose of our study was to investigate PDFF-based TA of paraspinal muscles as a predictor of muscle strength, as compared to mean PDFF. We performed 3T-MRI of the lumbar spine in 26 healthy subjects (age = 30 ± 6 years; 15 females) using a six-echo 3D spoiled gradient echo sequence for chemical-shift-encoding-based water–fat separation. Erector spinae (ES) and psoas (PS) muscles were segmented bilaterally from level L2–L5 to extract mean PDFF and texture features. Muscle flexion and extension strength was measured with an isokinetic dynamometer. Out of the eleven texture features extracted for each muscle, Kurtosis(global) of ES showed the highest significant correlation (r = 0.59, p = 0.001) with extension strength and Variance(global) of PS showed the highest significant correlation (r = 0.63, p = 0.001) with flexion strength. Using multivariate linear regression models, Kurtosis(global) of ES and BMI were identified as significant predictors of extension strength (R2adj = 0.42; p &lt; 0.001), and Variance(global) and Skewness(global) of PS were identified as significant predictors of flexion strength (R2adj = 0.59; p = 0.001), while mean PDFF was not identified as a significant predictor. TA of CSE-MRI-based PDFF maps improves the prediction of paraspinal muscle strength beyond mean PDFF, potentially reflecting the ability to quantify the pattern of muscular fat infiltration. In the future, this may help to improve the pathophysiological understanding, diagnosis, monitoring and treatment evaluation of diseases with paraspinal muscle involvement, e.g., NMD and LBP

Effects of zinc oxide nanoparticles on growth performance and concentrations of malondialdehyde, zinc in tissues, and corticosterone in broiler chickens under heat stress conditions

The use of nanominerals, such as nano-zinc, represents a promising and emerging technology in the animal farming industry. Due to the small particle size and bioavailability of nano-zinc, it can be easily assimilated in the digestive system, thereby reducing excretion and environmental pollution. The present study was conducted to assess the effects of zinc oxide nanoparticles (ZnONPs) on the growth performance, zinc (Zn) concentration in edible tissues, thiobarbituric acid reactive substance, and corticosterone concentrations in broilers reared under normal or heat stress environmental conditions. The experiment was performed with a completely randomized design based on a 4 × 2 factorial arrangement consisting of 4 diets (basal diet + 60 mg/kg conventional zinc oxide as control diet; basal diet + 40 mg/kg of ZnONPs; basal diet + 60 mg/kg of ZnONPs; and basal diet + 100 mg/kg of ZnONPs) and 2 environmental conditions (normal and heat stress). On day 22, birds from each dietary group were divided equally to normal temperature (23 ± 1°C throughout) or heat stress conditions (34 ± 1°C daily for 6 h from 10:00 am until 4:00 pm). From 1 to 42 D of age, the broiler chickens fed 100 mg/kg ZnONPs exhibited lower feed intake and feed conversion ratio than the control. The accumulation of Zn in the liver of broilers was significantly higher among all treatment groups compared to breast and thigh muscle tissues regardless of the temperature conditions. At 40 and 60 mg/kg ZnONPs, the malondialdehyde content increased in thigh muscle of broilers at 7 D postmortem, indicating that ZnONPs potentially inhibited the antioxidant system in muscle tissues. The control and ZnONPs at 40 mg/kg and 60 mg/kg led to low serum corticosterone levels that may be attributed to the antioxidant and antistress properties of Zn. Taken together, although supplementation with ZnONPs at 40 mg/kg and 60 mg/kg alleviated the negative results of heat stress, further research is needed to determine the optimal level of dietary ZnONPs supplementation

Association of Thigh Muscle Strength with Texture Features Based on Proton Density Fat Fraction Maps Derived from Chemical Shift Encoding-Based Water-Fat MRI

Purpose: Based on conventional and quantitative magnetic resonance imaging (MRI), texture analysis (TA) has shown encouraging results as a biomarker for tissue structure. Chemical shift encoding-based water–fat MRI (CSE-MRI)-derived proton density fat fraction (PDFF) of thigh muscles has been associated with musculoskeletal, metabolic, and neuromuscular disorders and was demonstrated to predict muscle strength. The purpose of this study was to investigate PDFF-based TA of thigh muscles as a predictor of thigh muscle strength in comparison to mean PDFF. Methods: 30 healthy subjects (age = 30 ± 6 years; 15 females) underwent CSE-MRI of the lumbar spine at 3T, using a six-echo 3D spoiled gradient echo sequence. Quadriceps (EXT) and ischiocrural (FLEX) muscles were segmented to extract mean PDFF and texture features. Muscle flexion and extension strength were measured with an isokinetic dynamometer. Results: Of the eleven extracted texture features, Variance(global) showed the highest significant correlation with extension strength (p 2adj = 0.712), and Correlation showed the highest significant correlation with flexion strength (p = 0.016, R2adj = 0.658). Multivariate linear regression models identified Variance(global) and sex, but not PDFF, as significant predictors of extension strength (R2adj = 0.709; p 2adj = 0.674; p < 0.001). Conclusions: Prediction of quadriceps muscle strength can be improved beyond mean PDFF by means of TA, indicating the capability to quantify muscular fat infiltration patterns