39 research outputs found

    Data-Driven Approach based on Deep Learning and Probabilistic Models for PHY-Layer Security in AI-enabled Cognitive Radio IoT.

    Get PDF
    PhD Theses.Cognitive Radio Internet of Things (CR-IoT) has revolutionized almost every eld of life and reshaped the technological world. Several tiny devices are seamlessly connected in a CR-IoT network to perform various tasks in many applications. Nevertheless, CR-IoT su ers from malicious attacks that pulverize communication and perturb network performance. Therefore, recently it is envisaged to introduce higher-level Arti cial Intelligence (AI) by incorporating Self-Awareness (SA) capabilities into CR-IoT objects to facilitate CR-IoT networks to establish secure transmission against vicious attacks autonomously. In this context, sub-band information from the Orthogonal Frequency Division Multiplexing (OFDM) modulated transmission in the spectrum has been extracted from the radio device receiver terminal, and a generalized state vector (GS) is formed containing low dimension in-phase and quadrature components. Accordingly, a probabilistic method based on learning a switching Dynamic Bayesian Network (DBN) from OFDM transmission with no abnormalities has been proposed to statistically model signal behaviors inside the CR-IoT spectrum. A Bayesian lter, Markov Jump Particle Filter (MJPF), is implemented to perform state estimation and capture malicious attacks. Subsequently, GS containing a higher number of subcarriers has been investigated. In this connection, Variational autoencoders (VAE) is used as a deep learning technique to extract features from high dimension radio signals into low dimension latent space z, and DBN is learned based on GS containing latent space data. Afterward, to perform state estimation and capture abnormalities in a spectrum, Adapted-Markov Jump Particle Filter (A-MJPF) is deployed. The proposed method can capture anomaly that appears due to either jammer attacks in transmission or cognitive devices in a network experiencing di erent transmission sources that have not been observed previously. The performance is assessed using the receiver

    Wrf-chem simulation for modeling seasonal variations and distributions of aerosol pollutants over the middle east

    Get PDF
    Atmospheric aerosols and dust have become a challenge for urban air quality. The pre-sented study quantified seasonal spatio-temporal variations of aerosols, tropospheric ozone, and dust over the Middle East (ME) for the year 2012 by using the HTAP emission inventory in the WRF-Chem model. Simulated gaseous pollutants, aerosols and dust were evaluated against satellite measurements and reanalysis datasets. Meteorological parameters, temperature, and wind vector were evaluated against MERRA2. The model showed high spatio-temporal variability in meteorological parameters during summer and low variability in winter. The correlation coefficients for all the parameters are estimated to be 0.92, 0.93, 0.98, and 0.89 for January, April, July, and October respectively, indicating that the WRF-Chem model reproduced results very well. Simulated monthly mean AOD values were maximum in July (1.0–1.5) and minimum in January (0.1–0.4) while April and October were in the range of 0.6–1.0 and 0.3–0.7 respectively. Simulated dust concentrations were high in April and July. The monthly average aerosol concentration was highest over Bahrain, Kuwait, Qatar, and the United Arab Emirates and Jeddah, Makkah. The contributions to urban air pollution were highest over Makkah city with more than 25% from anthropogenic sources

    REVERSE ENGINEERING IN MODELING OF AIRCRAFT PROPELLER BLADE - FIRST STEP TO PRODUCT OPTIMIZATION

    Get PDF
    ABSTRACT: Propeller aircrafts have had many ups and downs throughout their use in the aviation history. Due to the current economic recession and price hikes in fuels, propeller aircrafts may yet again be a choice for aerial transport and has thus re-emerged as an active area for research. On modern propeller aircrafts old aluminum propellers are being replaced with fiber reinforced composite propellers. However, owing to their reliability, strength, and integrity, aluminum propellers are still used in military aircrafts. One of the challenges that engineers of these aircraft-type have had to deal with is the non-availability of engineering drawings of these propellers. It is practically impossible to carry out any study, research or modification on such propellers in the absence of correct CAD data. This article proposes a methodology wherein a CAD model of a C-130 aircraft propeller blade can be constructed using reverse engineering techniques. Such a model would help in future aerodynamic as well as structural analyses which includes investigation on structural integrity and the fluid dynamics characteristics of propeller blades. Different steps involved in this process are discussed; starting from laser scanning to obtain the cloud of points data and subsequently generating a CAD model in a commercial CAD software. The model is then imported into an analysis software where quality surface meshes are generated using tetrahedral elements. The purpose is to prepare a meshed model for future computational analysis including CFD (Computational Fluid Dynamics) and FE (Finite Element) analysis. ABSTRAK: Pesawat bebaling mempunyai tempoh pasang surutnya sepanjang penggunaanya dalam sejarah penerbangan. Kini disebabkan oleh kemelesetan ekonomi dan kenaikan harga minyak, pesawat bebaling mungkin akan merupakan pengangkutan udara pilihan dan seterusnya muncul semula sebagai ruangan aktif penyelidikan. Pada pesawat bebaling moden, bebaling aluminium yang lama digantikan dengan bebaling komposit yang diperkuatkan gentian. Namun, disebabkan oleh keupayaan, kekuatan dan integritinya, bebaling aluminium masih diguna pakai bagi pesawat tentera. Salah satu cabaran jurutera bagi pesawat jenis ini, adalah apabila berhadapan dengan tidak adanya lukisan kejuruteraan bagi bebaling ini. Agak mustahil untuk menjalankan sebarang ujian, kajian atau modifkasi terhadap bebaling jenis ini kerana tidak adanya data yang tepat daripada Reka Bentuk Berbantukan Komputer (CAD). Artikel ini mencadangkan metodologi di mana model Reka Bentuk Berbantukan Komputer (CAD) bagi kipas bebaling pesawat C-130 boleh dibina menggunakan teknik kejuruteraan balikan. Model sebegini akan bakal dapat membantu bidang aerodinamik di masa hadapan. Begitu juga dengan analisis struktur yang melibatkan penyelidikan terhadap integriti struktur dan ciri-ciri dinamik bendalir kipas bebaling.  Beberapa proses berbeza diperbincangkan; bermula dengan imbasan laser untuk memperolehi poin kumpulan data dan seterusnya menjanakan model Reka Bentuk Berbantukan Komputer (CAD) dengan menggunakan pengaturcara komersil. Model kemudiannya diimport ke dalam pengaturcara analisis di mana jejaring permukaan dijanakan dengan menggunakan unsur tetrahedron. Ini bertujuan bagi menyediakan model jejaring untuk analisis berkomputer di masa hadapan, termasuklah analisis CFD (Gambar Rajah Aliran Kawalan) dan FE (Unsur Terhingga). KEYWORDS: reverse engineering; cloud data; laser scanning; CAD modeling; propeller blad

    Patterns of Head Injuries in Pediatric Patients Treated in Emergency Department of Children Hospital and Institute of Child Health Lahore

    Get PDF
    Objective:  To analyze the pattern of head injuries along with characteristics and outcomes among pediatric age group presenting in The Children hospital Lahore, Pakistan. Material and Methods:  A cross-sectional study was conducted and a total of 384 children of both genders aged up to 12 years presenting with head injuries were included. After initial review and resuscitation by the trauma unit or neurosurgery unit, children were evaluated clinically and radiologically and the plan was decided for further treatment. Gender, age, place of injury occurrence, etiology of injury, Glasgow coma score (GCS) at the time of enrollment, the interval between injury and admission, management, outcome, and total duration of hospital stay were recorded on a predesigned proforma. Results:  In a total of 384 children, 249 (64.8%) were boys. Overall, the mean age was 5.8 ± 3.3 years. Falls were the commonest etiology in 210 (54.7%) children while motor vehicle accidents were the cause of head trauma among 78 (20.3%) children. The mean interval between injury and presentation was noted to be 3.2 ± 2.1 hours. Mortality was reported in 56 (14.6%) children and it was observed that a significant association was noted between outcome and GCS at the time of presentation (p < 0.0001). Conclusion:  The majority of the pediatric head injury cases were male and aged above 5 years. The most common etiology of head injuries was falls followed by motor vehicle accidents. GCS ? 8 at the time of presentation was significantly linked with poor outcomes

    Evaluating National Innovation System of Malaysia Based on University-industry Research Collaboration: A System Thinking Approach

    Get PDF
    National innovation system (NIS) is an essential, effective and dynamic factor for the development of the nation. Despite the enormous research activities on NIS, there have been certain issues still remaining in this domain specially, in developing countries. Several articles have been published to deal with the factors affecting NIS of Malaysia but the role of research collaboration between university and industry (UIRC) on NIS is totally unattended in mainstream literature. Thus, the objective of this study is to determine the influence of UIRC on the NIS of Malaysia. Additionally, this study aims to indicate the current innovation performance and to identify the existing constraints of NIS. For the purpose of system modeling, system thinking approach is used to conceptualize and analyze the effect of UIRC on NIS. The result of this research shows that constraints of UIRC in Malaysia negatively influence on the success of NIS

    Silver nanoparticles protect tillering in drought-stressed wheat by improving leaf water relations and physiological functioning

    Get PDF
    The tillering phase of wheat (Triticum aestivum) crops is extremely susceptible to drought. We explored the potential of silver nanoparticles (AgNPs) in protecting wheat genotypes from drought injury during this sensitive stage. After treating with AgNPs (60 ppm), the plants were submitted to different water levels; i.e. 100% field capacity (FC), 75% FC (mild drought), 50% FC (moderate drought) and 25% FC (severe drought) from 15 to 41 days after sowing (tillering phase). Leaf physiological data were collected at stress termination, while yield attributes were recorded at crop maturity. We found that increasing drought intensity significantly impaired leaf physiology and grain yield of both studied genotypes. Compared with control, moderately and severely drought-stressed plants produced 25% and 45% lesser grain yield per spike, respectively (averaged across genotypes and years of study). Likewise, moderate and severe drought reduced photosynthesis by 49% and 76%, respectively, compared with control. In contrast, AgNPs significantly restored leaf physiological functioning and grain yield formation at maturity. For example, under moderate and severe drought, AgNPs-treated plants produced 22% and 17% more grains per plant, respectively, than their respective water-treated plants. Our study suggests that exogenous AgNPs can protect wheat crops from drought during early development stages

    Anaerobic membrane bioreactors for biohydrogen production: recent developments, challenges and perspectives

    Get PDF
    Biohydrogen as one of the most appealing energy vector for the future represents attractive avenue in alternative energy research. Recently, variety of biohydrogen production pathways has been suggested to improve the key features of the process. Nevertheless, researches are still needed to overcome remaining barriers to practical applications such as low yields and production rates. Considering practicality aspects, this review emphasized on anaerobic membrane bioreactors (AnMBRs) for biological hydrogen production. Recent advances and emerging issues associated with biohydrogen generation in AnMBR technology are critically discussed. Several techniques are highlighted that are aimed at overcoming these barriers. Moreover, environmental and economical potentials along with future research perspectives are addressed to drive biohydrogen technology towards practicality and economical-feasibility

    The Potential Impact of Climate Extremes on Cotton and Wheat Crops in Southern Punjab, Pakistan

    Get PDF
    The assessment of climate extremes’ impact on crop yield is essential to improve our understanding of agricultural resilience. In the present study, we analyzed the potential impact of climate extremes on wheat and cotton production in Southern Punjab, Pakistan using 30-year observed data from the Pakistan Meteorological Department (PMD) and the fifth-generation reanalysis data (ERA-5) from the European Center for Medium-Range Weather Forecasts (ECMWF). Cotton is a Kharif season crop that is sown in May and harvested in October, and wheat is a Rabi season crop that is planted in November and harvested in April. The agricultural data (1985–2015) that contained the crop area and crop yield were obtained from the Bureau of Statistics, Punjab for six selected districts in Southern Punjab. Three precipitation indices, namely consecutive dry days (CDD), consecutive wet days (CWD) and total precipitation of wet days (PRCPTOT), and four temperature indices, namely warm days (TX90p), warm nights (TN90p), cool days (TX10p) and cool nights (TN10p), were selected to analyze the potential impacts of climate extremes on crop production. (1) We found a potential association of TX10p, TN10p, TX90p and TN90p with crop yield in those years for which the production area remained the same. (2) In a few districts of the study area, the wheat yield losses in the Rabi season were associated with an increase in warmer days and warmer nights. (3) The grain size was suppressed due to an increase in the frequency of TX90p and TN90p, which ultimately reduced the net crop production. (4) In some districts, we found strong positive correlations between extreme temperature indices and crop yield; however, other potential factors such as the use of advanced technology, fertilizer, seeds, etc., may lead to improved net production. This study can help in adaptation planning for resilient agricultural production under the stress of climate extreme events in Southern Punjab

    Trends and future research in electronic marketing: a bibliometric analysis of twenty years

    Get PDF
    Artigo publicado em revista científica internacionalElectronic marketing (eM) is a flourishing phenomenon that is gaining intense concern because of a significant impact on organizational performance. Over the past few decades, the relevance of eM has been observed in numerous fields (e.g., consumers, organizational strategy, advertisement, and overall philosophy of management to understand the insights globally). To effectively maneuver the field, all stakeholders, particularly academicians and practitioners, must comprehend the current position of the eM theory and practices for dynamic utilization. A systematic bibliometric analysis can serve this issue by providing a holistic view of the publication trend and its trajectory in terms of various themes, including citations and publication metrics. This study analyzes the bibliometric data from 2000 to 2019 to reveal the most productive countries, universities, authors, journals, and prolific publications in electronic marketing. To this end, VOS viewer software was used to visualize the mapping based on co-citation, bibliographic coupling (BC), and co-occurrence (CC). The primary addition of this research is to provide an overview of eM tendencies and paths that may help researchers know the tendencies and future research directions worldwide.info:eu-repo/semantics/publishedVersio

    Comparison of Garden Soil with Nitrogen and Potassium for Growing Lettuce (Lactuca sativa L.) in Glass House.

    Get PDF
    The experiment was conducted during the year 2019-20 by Vegetable Section, Agriculture Research Station (ARS) Baffa Mansehra to compare garden soil with nitrogen (Urea) and potassium (Murate of Potash) for lettuce production in glass house. Lettuce is an important summer off-season and high valued crop cultivated at District Mansehra in the months of July-August. The produce is transported to other metropolises with handsome earning,  but excessive use of minerals and synthetic fertilizers may render the produce less profitable in one or another way. Hence this experiment was designed to compare garden soil with  nitrogen and potassium doses.  It is evident from the statistical analysis that garden soil has a significant effect on  number of leaves, leaf area, seed per plant, yield per plant and yield per acre. Seed production is noticeable for garden soil when the prevailing temperature during seed formation was 250C.  In terms of leaf area maximum leaf area 576.10 cm2was recorded for garden soil while minimum leaf area 303.43 cm2 was recorded with nitrogen applied @ 200 kg ha-1 and potassium applied @ 100 kg ha-1 respectively. Maximum number of leaves 28.03 was recorded for garden soil while the minimum number 21.96 was recorded for nitrogen applied @ 200 kg ha-1 and potassium applied @ 100 kg ha-1. Seed formation was successful with mean temperature 250C in glass house for 30 days, here again garden soil surpassed nitrogen and potassium with 4.03gm plant-1. Yield per plot 3.69 kg was recorded for garden soil and the minimum value 1.1843 kg was recorded for nitrogen and potassium applied @ 200 kg ha-1 nitrogen while potassium applied @ 100 kg ha-1. Garden soil gives maximum yield of 13600 kg acre-1 compared with the lowest production 6070.5 kg acre-1 of nitrogen and potassium applied @ 200 kg ha-1 nitrogen while potassium applied @ 150 kg ha-1.  Keywords:, Lettuce, garden soil, leaf area, seed production, glass house DOI: 10.7176/CEIS/14-2-06 Publication date:May 31st 202
    corecore