504 results on '"Chethan Kumar"'
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2. Mapping behavioral intention studies in sports marketing research: a review and future research agenda
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Chethan Kumar and Tijo George
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Sports Marketing ,Sports Business ,Sports Management ,Marketing Management ,Sport and Leisure Studies ,Kaouther Kooli, Bournemouth University, United Kingdom of Great Britain and Northern Ireland ,Business ,HF5001-6182 ,Management. Industrial management ,HD28-70 - Abstract
This study aims to provide a scientific and extensive review of behavioral intention studies in sports marketing research. Also, it informs directions for further studies that help in progressing sports marketing research. 362 articles were extracted using the Scopus database, and an extensive review of these articles was performed using the VOSviewer and Biblioshiny software tools. The performance analysis reveals the most influential articles, authors, sources, organizations, and countries in this domain. The thematic map and trend topic show the domain’s development and relevance. The co-citation network revealed four distinct research clusters, themed (a) Sponsorship in sports marketing, (b) Sports as service, (c) Behavioral intention analysis methods in Sports marketing, and (d) Theories and concepts. Finally, the results are summarized using the Theory, Context, and Methodology (TCM) framework. Along with the TCM framework, cluster analysis will also provide avenues for further studies in the form of research questions pertaining to each research cluster.
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- 2024
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3. Optimizing Energy-Harvesting Hybrid VLC/RF Networks With Random Receiver Orientation
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Amir Hossein Fahim Raouf, Chethan Kumar Anjinappa, and Ismail Guvenc
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Hybrid VLC-RF ,dc bias ,energy harvesting ,information rate ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
This paper investigates an indoor hybrid visible light communication (VLC) and radio frequency (RF) scenario with two-hop downlink transmission. A light emitting diode (LED) transmits both data and energy via VLC to an energy-harvesting relay node, which then uses the harvested energy to retransmit the decoded information to an RF user in the second phase. The design parameters include the direct current (DC) bias and the time allocation for VLC transmission. We formulate an optimization problem to maximize the data rate under decode-and-forward relaying with fixed receiver orientation. The non-convex problem is decomposed into two sub-problems, solved iteratively by fixing one parameter while optimizing the other. Additionally, we analyze the impact of random receiver orientation on the data rate, deriving closed-form expressions for both VLC and RF rates. An exhaustive search approach is employed to solve the optimization, demonstrating that joint optimization of DC bias and time allocation significantly enhances the data rate compared to optimizing DC bias alone.
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- 2024
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4. Epidemiological, Pathological, and Molecular Studies on Sheeppox Disease Outbreaks in Karnataka, India
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Gundallahalli Bayyappa Manjunatha Reddy, Varun Kumar Krishnappa, Chandan Dypasandra Siddalingaiah, Suguna Rao, Shivasharanappa Nayakvadi, Chethan Kumar Harlipura Basavarajappa, and Baldev Raj Gualti
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epidemiology ,pathology ,sheeppox ,disease outbreak ,P32 gene ,phylogenetic analysis ,Biology (General) ,QH301-705.5 - Abstract
An epidemiological study spanning twelve years has revealed that sheeppox disease is both widespread and endemic, predominantly surging during the winter and summer seasons. This investigation focused on sheeppox across 11 field outbreaks, involving 889 animals from non-migratory flocks across six districts in Karnataka, in the southern peninsula of India. Among these, 105 animals exhibited clinical signs suggestive of sheeppox, such as lesions on the body, and 95 cases were confirmed through PCR testing. The overall positivity rate for sheeppox stood at 10.68% (95 out of 889 animals). The incidence of sheeppox was notably higher in animals aged between 1 and 2 years and was more prevalent in females. Affected animals displayed symptoms including respiratory distress, weakness, fever, loss of appetite, depression, and various skin lesions ranging from papular to pock lesions across their bodies. There was a significant increase in total leukocyte count, while hemoglobin levels, red blood cell counts, and hematocrit values significantly decreased. On gross examination, sheeppox lesions, varying from vesicular to nodular forms, were predominantly found on hairless areas of the body. Microscopic examination of skin lesions revealed extensive changes, such as hyperkeratosis, parakeratosis, acanthosis, hydropic degeneration, and necrosis of epithelial cells, along with characteristic intracytoplasmic viral inclusions. The lungs exhibited type-II pneumocyte hyperplasia and proliferative bronchiolitis, also with intracytoplasmic inclusions. Confirmation of the sheeppox virus was achieved through PCR and subsequent sequence analysis. Phylogenetic analysis of the full-length P32 and RPO30 gene demonstrated homology with sheeppox isolates from various parts of India and neighboring countries, indicating that Indian sheeppox viruses are highly lineage-specific and correlate with the host of origin. Based on these findings, it is recommended to implement a homologous vaccination strategy, utilizing selective host/viral strains to enhance protection in susceptible animals.
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- 2024
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5. Aeroplane wing, a new recessive autosomal phenotypic marker in the malaria vector, Anopheles stephensi Liston
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Chaitali Ghosh, M. Soumya, Naveen Kumar, Chethan Kumar R, Soumya Gopal Joshi, Sampath Kumar, Suresh Subramani, and Sunita Swain
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Anopheles stephensi ,Aeroplane wings ,mutant ,Crossbreeding ,Autosomal ,Recessive ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
A novel and distinct mutant with a phenotype, aeroplane wing (ae) is reported for the first time in the urban malaria vector Anopheles stephensi. The main aim of this study was to establish the mode of inheritance of the ae gene performing genetic crossings between the mutants and wild types. These mutants show extended open wings that are visible to naked eyes in both the sexes. Mutants were first noticed in a nutritionally stressed isofemale colony. Strategic genetic crosses revealed that the ae gene is a recessive, autosomal, and monogenic trait having full penetrance with uniform expression in its adult stage. Egg morphometric analysis confirmed that these mutants were intermediate variant. No significant differences were observed in the wing venation and size of ae mutants compared to their control parental lines. Further cytogenetic analysis on the ovarian polytene chromosome of ae mutant showed an inversion (3Li) on the 3L arm like its parental line. This ae mutant would be a prominent marker and could be useful to study the functions of related specific genes within its genome.
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- 2024
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6. Copro-prevalence of Cryptosporidium in pigs of selected districtsin West coast of India: A preliminary study
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CHETHAN KUMAR H B, CHANDISHA D S, SOLOMON RAJKUMAR, SHIVASHARANAPPA N, SUSITHA R, UDHARWAR S V, and CHAKURKAR E B
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Cryptosporidium, India, Pigs, Prevalence, West coast ,Animal culture ,SF1-1100 - Abstract
In India, Cryptosporidium spp. have been detected and characterised from humans and domestic animals, mostly ruminants. Although pigs can act as an important reservoir of Cryptosporidium infection to humans, comprehensive studies have not been conducted in pig population in India. Hence, present study attempt to elucidate the prevalence and diversity of Cryptosporidium infection in pigs in the selected districts of three states situated in the West coast of India. The pig faecal samples (n=221) were subjected to coprological examination using modified Ziehl Neelsen (mZN) staining method, followed by polymerase chain reaction to detect Cryptosporidium spp. Using mZN staining method, 1.35% (95% CI, 0.46%–3.91%) of the samples were found positive for Cryptosporidium oocyst. However, the DNA from Cryptosporidium positive faecal samples could not be amplified using polymerase chain reaction probably because of the low sensitivity of the PCR and or low oocyst number in the faecal sample. Cryptosporidium spp. of pig origin have zoonotic potential and a certain proportion of pigs infected with Cryptosporidium may be apparently healthy. Therefore, the pig farmers need to be made aware of hygienic practices while handling pigs and pig manure and and general public must be made sensitised about the good agricultural practices and standard food hygiene practices to prevent foodborne Cryptosporidium infection.
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- 2023
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7. Enrichment of phenotype among biological forms of Anopheles stephensi Liston through establishment of isofemale lines
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Chaitali Ghosh, Naveen Kumar, Raja Babu Singh Kushwah, Soumya M., Soumya Gopal Joshi, Chethan Kumar Ramanjini, Tejashwini Alalamath, Subhashini Srinivasan, Suresh Subramani, Sampath Kumar, and Sunita Swain
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Anopheles stephensi ,Isofemale ,Biological forms ,Vectorial competence ,Insecticides ,Homozygosity ,Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Background Vector management programs rely on knowledge of the biology and genetic make-up of mosquitoes. Anopheles stephensi is a major invasive urban malaria vector, distributed throughout the Indian subcontinent and Middle East, and has recently been expanding its range in Africa. With the existence of three biological forms, distinctly identifiable based on the number of ridges on eggs and varying vectorial competence, An. stephensi is a perfect species for developing isofemale lines, which can be tested for insecticide susceptibility and vectorial competence of various biological forms. Methods We describe key steps involved in establishment and validation of isofemale lines. Isofemale colonies were further used for the characterization of insecticide susceptibility and differential vector competence. The results were statistically evaluated through descriptive and inferential statistics using Vassar Stat and Prism GraphPad software packages. Results Through a meticulous selection process, we overcame an initial inbreeding depression and found no significant morphometric differences in wings and egg size between the parental and respective isofemale lines in later generations. IndCh and IndInt strains showed variations in resistance to different insecticides belonging to all four major classes. We observed a significant change in vectorial competence between the respective isofemale and parental lines. Conclusions Isofemale lines can be a valuable resource for characterizing and enhancing several genotypic and phenotypic traits. This is the first detailed report of the establishment of two isofemale lines of type and intermediate biological forms in Anopheles stephensi. The work encompasses characterization of fitness traits among two lines through a transgenerational study. Furthermore, isofemale colonies were established and used to characterize insecticide susceptibility and vector competence. The study provides valuable insights into differential susceptibility status of the parental and isofemale lines to different insecticides belonging to the same class. Corroborating an earlier hypothesis, we demonstrate the high vector competence of the type form relative to the intermediate form using homozygous lines. Using these lines, it is now possible to study host-parasite interactions and identify factors that might be responsible for altered susceptibility and increased vector competence in An. stephensi biological forms that would also pave the way for developing better vector management strategies. Graphical Abstract
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- 2023
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8. Environmentally benign silver bio-nanomaterials as potent antioxidant, antibacterial, and antidiabetic agents: Green synthesis using Salacia oblonga root extract
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Guru Kumar Dugganaboyana, Chethan Kumar Mukunda, Anisha Jain, Raghavendra Mandya Kantharaju, Rani R. Nithya, Divya Ninganna, Rathi Muthaiyan Ahalliya, Ali A. Shati, Mohammad Y. Alfaifi, Serag Eldin I. Elbehairi, Ekaterina Silina, Victor Stupin, Gopalakrishnan Velliyur Kanniappan, Raghu Ram Achar, Chandan Shivamallu, and Shiva Prasad Kollur
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Salacia oblonga ,green synthesis ,nanoparticles ,biomaterials ,FT-IR ,Chemistry ,QD1-999 - Abstract
Introduction: The use of plant extracts in the green synthesis of metallic nanoparticles is one of the simplest, most practical, economical, and ecologically friendly methods for avoiding the use of toxic chemicals.Method: Silver nanoparticles (AgNPs) were synthesized, employing a high-efficiency, non- toxic, cost-effective, green, and simple technique that included the use of Salacia oblonga root extract (SOR) as a capping agent compared to synthetic nanoparticles. The use of S. oblonga can be seen in traditional medicines for treating diabetes, obesity, rheumatism, gonorrhea, asthma, and hyperglycemia. The objectives of the current study were to green synthesize S. oblonga root extract silver nanoparticles (SOR-AgNPs), characterize them, and study their antioxidant, antibacterial, and antidiabetic activities.Result: The shape of SOR-AgNPs was spherical, at less than 99.8 nm in size, and exhibited a crystalline peak at XRD. The green synthesized SOR-AgNPs showed significant antioxidant properties like DPPH (80.64 μg/mL), reducing power capacity (81.09 ± SEM μg/mL), nitric oxide (96.58 μg/mL), and hydroxyl (58.38 μg/mL) radical scavenging activities. The MIC of SOR-AgNPs was lower in gram-positive bacteria. The SOR-AgNPs have displayed efficient inhibitory activity against α-amylase, with an EC50 of 58.38 μg/mL. Analysis of capping protein around the SOR-AgNPs showed a molecular weight of 30 kDa.Discussion: These SOR-AgNPs could be used as antibacterial and antidiabetic drugs in the future as it is cheap, non-toxic, and environmentally friendly. Bio-fabricated AgNPs had a significant impact on bacterial strains and could be used as a starting point for future antibacterial drug development.
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- 2023
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9. In vitro Comparison of Adipogenic Differentiation in Human Adipose-Derived Stem Cells Cultured with Collagen Gel and Platelet-Rich Fibrin
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Pallavi Priyadarshini, Soumi Samuel, Basan Gowda Kurkalli, Chethan Kumar, Basavarajappa Mohana Kumar, Nikhil Shetty, Veena Shetty, and Karthik Vishwanath
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adipose-derived stem cells ,collagen ,platelet-rich fibrin ,adipogenic differentiation ,in vitro ,Surgery ,RD1-811 - Abstract
Background: Adipose-derived stem cells (ADSCs) are the most preferred cell type, based on their phenotypic characteristics, plasticity, and favorable immunological properties for applications in soft-tissue augmentation. Hence, the present in vitro study was aimed to evaluate the adipogenic differentiation potential of human ADSCs upon culturing individually with collagen gel and platelet-rich fibrin (PRF). Materials and methods: The collected lipoaspirate was used for establishing ADSCs using enzymatic digestion method. Then, the cells were analyzed for their morphology, viability, proliferation rate, population doubling time (PDT), colony-forming ability, cell surface markers expression, and osteogenic differentiation as biological properties. Further, ADSCs were evaluated for their adipogenicity using induction media alone, and by culturing with collagen gel and PRF individually for prospective tissue augmentation. Results: ADSCs were successfully established in vitro and exhibited a fibroblast-like morphology throughout the culture period. Cells had higher viability, proliferation potential and showed their ability to form colonies. The positive expression of cell surface markers and osteogenic ability confirmed the potency of ADSCs. The ADSCs cultured on collagen gel and PRF, individually, showed higher number of differentiated adipocytes than ADSCs grown with adipogenic induction medium alone. Conclusion: The extent of lipid accumulation by ADSCs was slightly higher when cultured on collagen gel than on PRF. Additional experiments are required to confirm better suitability of scaffold materials for soft-tissue regeneration.
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- 2021
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10. Copper chelating protein hydrolysate from Salvia hispanica L. by pepsin-pancreatin treatment
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Latha B V, Likhitha R, and Chethan Kumar M
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Chia seed ,Protein hydrolysate ,Copper chelating peptides ,Nutrition. Foods and food supply ,TX341-641 ,Food processing and manufacture ,TP368-456 - Abstract
Salvia hispanica L. (Chia) seeds are good source of proteins with diverse health benefits. The seed protein was extracted through alkaline solubilisation followed by acid precipitation to separate fibres and are digested sequentially by pepsin and pancreatin. Enzyme-substrate ratio, temperature and contact time had high impact on degree of hydrolysis affecting their chelating ability. Maximum degree of hydrolysis (14.06%) and maximum copper chelation (74.98%) was obtained at 4% w/w enzyme-substrate ratio at 37 °C for 4 h. Copper chelating enzymatic hydrolysate was isolated by HiTrap chelating column and purified further by rpHPLC. Out of nine fractions obtained by rpHPLC the sixth fraction with 93.09 ± 0.16% of copper chelating activity and 82.91 ± 0.52% of antioxidant activity was further characterized as Copper chelating Chia Protein Hydrolysate (CCPH). Ultraviolet spectroscopy and fluorescence spectroscopic studies revealed the interaction of the major chelating sites of the CCPH with the copper divalent ion. The purified CCPH was subjected to LC-MS/ESI-TOF analysis from which six major intense peaks obtained with m/z value ranging from 0.4 kDa to 2.5 kDa were identified and sequenced using Mascot database. The functional behaviour and the binding capacity of these peptides were analysed by their amino acid composition. The CCPH was stable in a simulated gastric condition and its chelating ability remained unaltered. These results explored an informative bioactive peptides with varied activity and one valuable among is the copper chelating with antioxidant property. Furthermore, these Chia seed protein hydrolysates can be useful as dietary supplements to enhance mineral bioavailability.
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- 2021
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11. Harnessing the antibacterial activity of Quercus infectoria and Phyllanthus emblica against antibiotic-resistant Salmonella Typhi and Salmonella Enteritidis of poultry origin
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Amruta Nair, T. Balasaravanan, Sunil Jadhav, Vysakh Mohan, and Chethan Kumar
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antimicrobial-resistant ,phyllanthus emblica ,phytochemicals ,gas chromatography-mass spectrometry ,quercus infectoria ,salmonella ,Animal culture ,SF1-1100 ,Veterinary medicine ,SF600-1100 - Abstract
Background and Aim: In a scenario of the ineffectiveness of the current drugs against antibiotic-resistant pathogens, the herbal extracts can serve as an alternative remedy. This study appraises the antibacterial potency of Quercus infectoria (gall), Phyllanthus emblica (fruit) individually and synergistically against antimicrobial-resistant (AMR) Salmonella Typhi and Salmonella Enteritidis in a time and dose-dependent manner. Further, the antibacterial phytocompounds were identified employing gas chromatography-mass spectrometry (GC-MS). Materials and Methods: Preliminary antibacterial activity of the plant extracts was assessed using the agar disk diffusion method. In vitro evaluations of Q. infectoria methanolic extract (QIME) and P. emblica methanolic extract (PEME) against S. Typhi and S. Enteritidis were carried out using plate count method. Results: QIME and PEME at a dose rate of 50 mg/ml and 25 mg/ml, respectively, had a complete bactericidal effect on AMR S. Typhi and S. Enteritidis whereas 10 log10 CFU/ml of exponential growth was seen in untreated control groups. At the lower concentrations, QIME and PEME had a significant bacteriostatic effect (3-6 log10 reduction of the test isolates). The synergistic antibacterial effect obtained from the combination of these two plant extracts at 12.5 mg/ml was superior (p
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- 2020
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12. A critical review on neonatal hyperbilirubinemia-an Ayurvedic perspective
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Shubhangi Rathore, Chethan Kumar VK, and Sharashchandra R
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Neonatal jaundice ,Ayurveda ,Pathology ,Kamala ,Miscellaneous systems and treatments ,RZ409.7-999 - Abstract
Neonatal hyperbilirubinemia is the elevation of the bilirubin level in the newborns blood, which results in yellowish staining of the skin and sclera of the newborn eyes by pigment of bile. It is due to the breakdown of RBC's (which release bilirubin into the blood) and the immaturity of newborns liver (which cannot effectively metabolize the bilirubin and prepare it for excretion into the urine). Increased bilirubin production, reduced hepatic clearance and enhanced enterohepatic circulation are the sole causes of increased prevalence of jaundice in newborn. The science of Ayurveda is supposed to add a step in order to understand the pathophysiology of neonatal jaundice that have resemblance with clinical entity of kamala (jaundice) mentioned in Kashyapa Samhita. The concept of neonatal hyperbilirubinemia in Ayurveda can be understood in the context of Pittaja stanya dushti along with the physiological variations in the newborns leading to the raised level of unconjugated bilirubin. Therefore, the patho-physiology should be known by a pediatrician in Ayurveda based on the involvement of dosha, dhatu, mala and srotas. Hence, an attempt is made in this review to discuss about the hidden concept of pathology of neonatal jaundice described in Ayurveda. These findings to understand the concept of neonatal jaundice in Ayurveda add up to the Ayurvedic science that has been developed through ages.
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- 2020
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13. Detection and Classification of UAVs Using RF Fingerprints in the Presence of Wi-Fi and Bluetooth Interference
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Martins Ezuma, Fatih Erden, Chethan Kumar Anjinappa, Ozgur Ozdemir, and Ismail Guvenc
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Interference ,machine learning ,Markov models ,RF fingerprinting ,unmanned aerial vehicles (UAVs) ,UAV detection and classification ,Telecommunication ,TK5101-6720 ,Transportation and communications ,HE1-9990 - Abstract
This paper investigates the problem of detection and classification of unmanned aerial vehicles (UAVs) in the presence of wireless interference signals using a passive radio frequency (RF) surveillance system. The system uses a multistage detector to distinguish signals transmitted by a UAV controller from the background noise and interference signals. First, RF signals from any source are detected using a Markov models-based naïve Bayes decision mechanism. When the receiver operates at a signal-to-noise ratio (SNR) of 10 dB, and the threshold, which defines the states of the models, is set at a level 3.5 times the standard deviation of the preprocessed noise data, a detection accuracy of 99.8% with a false alarm rate of 2.8% is achieved. Second, signals from Wi-Fi and Bluetooth emitters, if present, are detected based on the bandwidth and modulation features of the detected RF signal. Once the input signal is identified as a UAV controller signal, it is classified using machine learning (ML) techniques. Fifteen statistical features extracted from the energy transients of the UAV controller signals are fed to neighborhood component analysis (NCA), and the three most significant features are selected. The performance of the NCA and five different ML classifiers are studied for 15 different types of UAV controllers. A classification accuracy of 98.13% is achieved by k-nearest neighbor classifier at 25 dB SNR. Classification performance is also investigated at different SNR levels and for a set of 17 UAV controllers which includes two pairs from the same UAV controller models.
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- 2020
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14. Evaluation of efficacy of four disinfectants on striated and non-striated orthodontic instruments: An in vitro study
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Nagaraj Venkatachalam, Niveddha Ramesh, Prasanna Turuvekere, SM Vignesh Prasad, Mohamad Ramees, and Chethan Kumar
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disinfection ,microbiological study ,orthodontic instruments ,sterilization ,Pharmacy and materia medica ,RS1-441 ,Analytical chemistry ,QD71-142 - Abstract
Introduction: To achieve effective infection control only disinfecting instruments is not perfect when sterilization is an ideal method. Few chemical disinfection methods have disadvantage of not killing spores as cross infection is of great importance in dentistry; Standard sterilization and disinfection protocols must be followed by dental health care professionals for efficient infection control. Aim: The aim of this study was to evaluate the efficacy of undiluted concentrations of Durr Dental system, Bacillol, Savlon, and Dettol for disinfection of striated and nonstriated orthodontic instruments. Materials and Methods: Orthodontic instruments were divided into two groups. Each group of instrument was exposed to three microbes: Streptococcus mutans, Candida albicans, and Bacillus subtilis. Once the instruments were exposed to bacterium, they were immersed in four commercially available disinfectants: Durr Dental solution, Bacillol, Dettol, and Savlon. Culture streaks were taken at 5, 10, and 15 min of contact time and growth of organisms was observed on culture media. Results: All the four disinfectants showed no growth of bacteria and all were significantly effective. As per the immersion time factor, Durr system and Bacillol were more efficient than Dettol and Savlon. Conclusion: Study concluded that there was no growth of bacteria after disinfecting in all the four disinfectants. Dettol and Savlon were unable to eliminate B. subtilis at 5 min of contact time. All the disinfectants were effective in eliminating the microorganisms at 10 and 15 min postexposure.
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- 2020
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15. Molecular characterization and multi-environmental evaluation of field corn (Zea mays) inbreds for kernel traits
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CHETHAN KUMAR V, R N GADAG, GANAPATI MUKRI, JAYANT S BHAT, CHANDU SINGH, JYOTI KUMARI, RAJIV K SINGH, and NAVIN C GUPTA
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AMMI analysis ,Gene based markers ,Kernel size ,Kernel weight ,Molecular diversity ,Agriculture - Abstract
Kernel size and kernel weight are important yield attributing traits in maize (Zea mays L.). Though yield hascomplex inheritance, understanding and improvement of yield per se becomes relatively easy, when maize breedingis targeted for genetic enhancement of yield component traits. In the present investigation, a set of 45 tropical fieldcorn inbred lines were evaluated under three environments and at different location for kernel length, kernel thicknessand kernel weight traits. In a given location, environmental influence on the expression of these traits were negligibleas it was evident by exhibition of high heritability (broad sense) for the traits under study, however pooled effect ofenvironments showed some interactions. Based on the AMMI stability value, the inbred lines AI 04 followed by AI 37,AI 18, AI 25 and AI 35 were selected as highly stable genotypes for its yield per se. Inbred lines were characterizedusing gene-based markers linked to kernel traits. It was observed that molecular markers rightly classified the inbredlines into different groups based on their trait means. Furthermore, the makers, umc1890 and umc1120 were putativelylinked to kernel weight and kernel thickness respectively. These markers may be utilized for identification of suitabledonor and genetic improvement of kernel traits driven maize improvement program.
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- 2021
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16. Cellular Properties and Expression of Pluripotent Markers in Human Dental Pulp Stem Cells Cultured in Serum-Free Medium
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Chethan Kumar, Basan Gowda Sharanappa Kurkalli, Shishir Shetty, AKSHAY BAIRAPURA MANJA, Veena Shetty, and Mohana Kumar Basavarajappa
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cellular therapy ,fetal bovine serum ,osteogenesis ,xenogeneic free ,Medicine - Abstract
Introduction: The standard isolation and expansion of human Dental Pulp Stem Cells (DPSCs) under invitro conditions normally involve the usage of Fetal Bovine Serum (FBS). However, its animal-origin poses possible concerns for clinically relevant procedures. This critical issue compels the use of Xenogeneic-Free (XF) or human-origin alternatives to FBS for culture expansion and differentiation of DPSCs to determine the usefulness for translating into therapeutic clinical applications. Aim: To evaluate the cellular characteristics and expression of pluripotent markers in DPSCs cultured using Serum-Containing Medium (SCM-DPSCs) and Serum-Free Medium (SFMDPSCs). Materials and Methods: This in-vitro descriptive study was conducted at NITTE (Deemed to be University), Mangaluru, Karnataka, India, from June 2019 to August 2020. DPSCs were isolated from impacted third molars. The culture expanded DPSCs in serum-containing and serum-free media were analysed on their morphology, viability, proliferation rate, Population Doubling Time (PDT), Alkaline Phosphatase (ALP) activity, cell surface markers expression, osteogenic and adipogenic potential, and the relative expression of selected pluripotent genes. Results: The primary culture of DPSCs established in SCM and SFM showed spindle shaped fibroblastic morphology with >80% viability from passage 1 (P1) to P4. A significant (p-value
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- 2021
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17. Joint Frame Synchronization and Channel Estimation: Sparse Recovery Approach and USRP Implementation
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Ozgur Ozdemir, Chethan Kumar Anjinappa, Ridha Hamila, Naofal Al-Dhahir, and Ismail Guvenc
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Equalization ,frame synchronization ,large delay spread ,MSE ,OMP ,software defined radio (SDR) ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Correlation-based techniques used for frame synchronization can suffer significant performance degradation over multi-path frequency-selective channels. In this paper, we propose a joint frame synchronization and channel estimation (JFSCE) framework as a remedy to this problem. This framework, however, increases the size of the resulting combined channel vector which should capture both the channel impulse response vector and the frame boundary offset and, therefore, its estimation becomes more challenging. On the other hand, because the combined channel vector is sparse, sparse channel estimation methods can be applied. We propose several JFSCE methods using popular sparse signal recovery algorithms which exploit the sparsity of the combined channel vector. Subsequently, the sparse channel vector estimate is used to design a sparse equalizer. Our simulation results and experimental measurements using software defined radios show that in some scenarios our proposed method improves the overall system performance significantly, in terms of the mean square error between the transmitted and the equalized symbols compared to the conventional method.
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- 2019
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18. Etiology, Clinical Profile and Factors Predicting Disease Recurrence of Rhinosporidiosis in a Tertiary Care Centre in Kanyakumari District
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Babu, Dayana, Joy, Lyra, Sebastian, Austin, Chethan Kumar, G., Noorjihan, B. K., and Rajadurai, V. Deepak
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- 2024
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19. Effects of bilateral superficial cervical plexus block on sevoflurane consumption during thyroid surgery under entropy-guided general anesthesia: a prospective randomized study
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Sudheesh Kannan, Nethra S Surhonne, Chethan Kumar R, Kavitha B, Devika Rani D, and Raghavendra Rao R S
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analgesia ,cervical plexus ,entropy ,nerve block ,sevoflurane ,thyroidectomy ,Anesthesiology ,RD78.3-87.3 - Abstract
Background Bilateral superficial cervical plexus block (BSCPB) provides good postoperative analgesia, but its effect on anesthetic consumption is unknown. This study evaluated the effects of BSCPB on sevoflurane consumption during thyroid surgery. Methods Fifty patients were randomly allocated into groups A and B of 25 each in this prospective double-blind study. Group A received BSCPB with 20 ml 0.25% bupivacaine, whereas group B received 20 ml saline immediately before entropy-guided general anesthesia. Intraoperative hemodynamic parameters, end-tidal sevoflurane concentration, minimum alveolar concentration, and sevoflurane consumption were recorded. Postoperative pain was assessed using a visual analog scale, and the time of the first request for analgesia was noted. All side effects were recorded. Results Demographics were comparable. Mean sevoflurane consumption [for 30 min: group A = 7.2 (1.1) ml, group B = 8.8 (2.0) ml, P = 0.001; for 60 min: group A = 13.5 (1.7) ml, group B = 16.5 (3.9) ml, P = 0.002] and mean end-tidal sevoflurane concentration [for 30 min: group A = 1.2% (0.2%), group B = 1.4% (0.2%), P = 0.008; for 60 min: group A = 1.2% (0.1%), group B = 1.4% (0.2%), P = 0.010] were significantly lower in group A. Patients in group A had a longer duration of analgesia [361.6 (79.5) min vs. 151.0 (60.2) min, P < 0.001] compared to those in group B. Conclusions Preinduction BSCPB during thyroid surgery significantly reduced sevoflurane consumption and increased the duration of postoperative analgesia.
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- 2018
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20. 3D FINITE ELEMENT MODEL TO PREDICT MACHINING INDUCED RESIDUAL STRESSES USING ARBITRARY LAGRANGIAN EULERIAN APPROACH
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PRAKASH MARIMUTHU K., THIRTHA PRASADA H. P., and CHETHAN KUMAR C. S.
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Machining ,Finite element analysis ,Residual stresses ,X-ray diffraction ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Technology (General) ,T1-995 - Abstract
Understanding the machining process at the microscopic level has been a challenge over the years. The machining process is very complex due to various factors, which are involved like friction, plastic deformation and material failure. The present works aims to develop a 3D Finite Element Model (FEM) to predict the residual stresses induced during the machining operation. Over the years, a lot of development has taken place particularly with the advent of high-end computers and FEM software packages. This work aims to incorporate the developments that have taken place recently in the field of Finite Element Analysis of machining processes and try to introduce an improved model to understand the machining process. Machining induced residual stresses were determined using X-ray diffraction method and compared with the simulation results. Present work is on AISI 1045 steel. Simulation results are in good agreement with the experimental results. Arbitrary Lagrangian Eulerian approach was used for finite element simulations. Many researchers use the orthogonal model to study most of the machining processes; 3D model enables us to see the oblique cutting process. In the present work a 3D model is used in order to be more realistic.
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- 2018
21. Comparison of Various Graft Materials in the Reconstruction of Ossicular Chain in Patients with Chronic Otitis Media: A Prospective Hospital Based Study
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Niaz Fakhruddin, Chethan Kumar Gangaiah, Gopakumar KP, Geogin George Thottan, and Mon Noufal
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Otitis Media, Suppurative ,Tympanoplasty ,Incus ,Necrosis ,Cartilage ,Medicine ,Otorhinolaryngology ,RF1-547 - Abstract
Introduction Ossicular chain reconstruction is the surgical procedure used to correct the hearing problems in patients with chronic otitis media (COM). In this era, where a large variety of innovative artificial prosthetic materials are being used to replace and reconstruct the ossicular chain, autografts still play a significant role. Materials and Methods The present study included 40 patients. Study population was selected based on inclusion and exclusion criteria. The ossicular reconstructive procedure was done under anesthesia and according to the status of the ossicular chain. Temporalis fascia was used to close the perforation. Mainly two procedures were performed: one is intact canal wall and the other is canal wall down. Results Most of the study population was middle aged and males were more compared to females. Thirty five patients had air bone gap above 30dB. In 38 patients, the incus had undergone necrosis. Most of the patients underwent short columella reconstruction. A closure of air bone gap with in 20 dB was achieved in 72.2% in patients with malleus stapes assembly. In short columella 22.2% of patients had closure of air bone gap within 20 dB. Incus remnant grafts gave better hearing gain. Discussion The published literature on the result of use of sculptured ossicle and cartilage in tympanoplasty have been reviewed Conclusion In the present study, cases with COM showed good hearing results patients implanted with autogenous cartilage and bone.
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- 2017
22. Evaluation of the effect of time dependent dosing on pharmacokinetic and pharmacodynamics of amlodipine in normotensive and hypertensive human subjects
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Samira Khodadoustan, Iran Nasri Ashrafi, K Vanaja Satheesh, Chethan Kumar, Shekar HS, and Chikkalingaiah S
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amlodipine ,chronopharmacodynamic ,chronopharmacokinetics ,hypertensive ,normotensive ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
In clinical practice, circadian rhythms play a prominent role in pharmacokinetics and cell responses to therapy, hence necessitating in designing a defined protocol for drug administration. Clinical evidence for chronopharmacological behavior of cardiovascular active drugs in human subjects has been limited for amlodipine. Hence, the present study was undertaken to study the chronopharmacokinetic and chronopharmacodynamic phenomena of amlodipine and evaluate the effect of time of dosage in hypertensive subjects. Single oral dose of amlodipine was administered to the hypertensive/normotensive subjects either morning or evening to assess the pharmacokinetic profile after morning dosing or evening dosing, respectively. PK parameters obtained revealed that Tmax was shorter and Cmax was greater after evening dosing than the morning dosing in both hypertensive and normotensive subjects. These observations were comparable with the hypothesis that amlodipine is absorbed rapidly when it is given during the night time. Also, the changes in systolicBP, DiastolicBP, and heart rate in comparison to the respective circadian baseline values were markedly different depending on the time and dosing. SBP and HR were significantly reduced after evening dosing with slight difference in measurement of DBP in hypertensive patients. Hence, it can be concluded that prescription of antihypertensive medications containing amlodipine, to be administered at night offers highly efficacious means to control BP without the need to increase either the dose or number of medications. The current treatment strategy method involves delivery of medications, so that they are synchronized in time to biological need that varies according to the chronobiology of the targeted tissues.
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- 2017
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23. Optimizing Energy-Harvesting Hybrid VLC/RF Networks with Random Receiver Orientation
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Raouf, Amir Hossein Fahim, Anjinappa, Chethan Kumar, and Guvenc, Ismail
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Electrical Engineering and Systems Science - Signal Processing ,Computer Science - Information Theory - Abstract
This paper investigates an indoor hybrid visible light communication (VLC) and radio frequency (RF) scenario with two-hop downlink transmission. A light emitting diode (LED) transmits both data and energy via VLC to an energy-harvesting relay node, which then uses the harvested energy to retransmit the decoded information to an RF user in the second phase. The design parameters include the direct current (DC) bias and the time allocation for VLC transmission. We formulate an optimization problem to maximize the data rate under decode-and-forward relaying with fixed receiver orientation. The non-convex problem is decomposed into two sub-problems, solved iteratively by fixing one parameter while optimizing the other. Additionally, we analyze the impact of random receiver orientation on the data rate, deriving closed-form expressions for both VLC and RF rates. An exhaustive search approach is employed to solve the optimization, demonstrating that joint optimization of DC bias and time allocation significantly enhances the data rate compared to optimizing DC bias alone.
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- 2023
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24. Multi-Parameter Optimization of mm-Wave Antenna Layout Using Hybrid Modeling and Incremental Model Learning.
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Ferhat Can Ataman, Mohammed Aladsani, Y. B. Chethan Kumar, Georgios C. Trichopoulos, and Sule Ozev
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- 2024
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25. Optimal Design of Energy-Harvesting Hybrid VLC-RF Networks
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Raouf, Amir Hossein Fahim, Anjinappa, Chethan Kumar, and Guvenc, Ismail
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Computer Science - Information Theory ,Electrical Engineering and Systems Science - Signal Processing - Abstract
In this paper, we consider an indoor downlink dual-hop hybrid visible light communication (VLC)/radio frequency (RF) scenario. For each transmission block, we dynamically allocate a portion of time resources to VLC and the other portion to RF transmission. In the first phase (i.e., VLC transmission), the LED carries both data and energy to an energy harvester relay node. In the second phase (i.e., RF communication), the relay utilizes the harvested energy to re-transmit the decoded information to the far RF user. During this phase, the LED continues to transmit power (no information) to the relay node, aiming to harvest energy that can be used in the next transmission block. We formulate the optimization problem in the sense of maximizing the data rate under the assumption of decode-and-forward (DF) relaying. As the design parameters, the direct current (DC) bias and the assigned time duration for VLC transmission are taken into account. In particular, the joint non-convex optimization is split into two sub-problems, which are then cyclically solved. In the first sub-problem, we fix the assigned time duration to VLC link and utilize the majorization-minimization (MM) procedure to solve the non-convex DC bias problem. In the second sub-problem, we fix the DC bias obtained in the previous step and solve the optimization problem for the assigned VLC link time duration. Our results demonstrate that a higher data rate can be achieved by solving the joint problem of DC bias and time duration compared to solely optimizing the DC bias.
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- 2022
26. Outage Analysis of Hybrid VLC/RF Networks With an Energy Harvesting Relay and Random Receiver Orientation.
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Amir Hossein Fahim Raouf, Chethan Kumar Anjinappa, and Ismail Güvenç
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- 2024
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27. Numerical and experimental studies on sustainable alkali activated concretes at elevated temperatures
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Yaragal, Subhash, B., Chethan Kumar, and Abhinav, Manoj Uddavolu
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- 2023
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28. Virtual Screening and Biological Evaluation of Piperazine Derivatives as Human Acetylcholinesterase Inhibitors
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Kavitha Raj Varadaraju, Jajur Ramanna Kumar, Lingappa Mallesha, Archana Muruli, Kikkeri Narasimha Shetty Mohana, Chethan Kumar Mukunda, and Umesha Sharanaiah
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Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 ,Geriatrics ,RC952-954.6 - Abstract
The piperazine derivatives have been shown to inhibit human acetylcholinesterase. Virtual screening by molecular docking of piperazine derivatives 1-(1,4-benzodioxane-2-carbonyl) piperazine (K), 4-(4-methyl)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S1), and 4-(4-chloro)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S3) has been shown to bind at peripheral anionic site and catalytic sites, whereas 4-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S4) and 4-(2,5-dichloro)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine (S7) do not bind either to peripheral anionic site or catalytic site with hydrogen bond. All the derivatives have differed in number of H-bonds and hydrophobic interactions. The peripheral anionic site interacting molecules have proven to be potential therapeutics in inhibiting amyloid peptides aggregation in Alzheimer’s disease. All the piperazine derivatives follow Lipinski’s rule of five. Among all the derivatives 1-(1,4-benzodioxane-2-carbonyl) piperazine (K) was found to have the lowest TPSA value.
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- 2013
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29. Comparative Analysis of Radar Cross Section Based UAV Classification Techniques
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Ezuma, Martins, Anjinappa, Chethan Kumar, Semkin, Vasilii, and Guvenc, Ismail
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Electrical Engineering and Systems Science - Signal Processing - Abstract
This work investigates the problem of unmanned aerial vehicles (UAVs) identification using their radar crosssection (RCS) signature. The RCS of six commercial UAVs are measured at 15 GHz and 25 GHz in an anechoic chamber, for both vertical-vertical and horizontal-horizontal polarization. The RCS signatures are used to train 15 different classification algorithms, each belonging to one of three different categories: statistical learning (SL), machine learning (ML), and deep learning (DL). The study shows that while the classification accuracy of all the algorithms increases with the signal-to-noise ratio (SNR), the ML algorithm achieved better accuracy than the SL and DL algorithms. For example, the classification tree ML achieves an accuracy of 98.66% at 3 dB SNR using the 15 GHz VV-polarized RCS test data from the UAVs. We investigate the classification accuracy using Monte Carlo analysis with the aid of boxplots, confusion matrices, and classification plots. On average, the accuracy of the classification tree ML model performed better than the other algorithms, followed by the Peter Swerling statistical models and the discriminant analysis ML model. In general, the classification accuracy of the ML and SL algorithms outperformed the DL algorithms (Squeezenet, Googlenet, Nasnet, and Resnet 101) considered in the study. Furthermore, the computational time of each algorithm is analyzed. The study concludes that while the SL algorithms achieved good classification accuracy, the computational time was relatively long when compared to the ML and DL algorithms. Also, the study shows that the classification tree achieved the fastest average classification time of about 0.46 ms., Comment: 17 pages
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- 2021
30. Channel Rank Improvement in Urban Drone Corridors Using Passive Intelligent Reflectors
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Ozturk, Ender, Anjinappa, Chethan Kumar, Erden, Fatih, Guvenc, Ismail, Dai, Huaiyu, and Bhuyan, Arupjyoti
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Electrical Engineering and Systems Science - Signal Processing - Abstract
Multiple-input multiple-output (MIMO) techniques can help in scaling the achievable air-to-ground (A2G) channel capacity while communicating with drones. However, spatial multiplexing with drones suffers from rank deficient channels due to the unobstructed line-of-sight (LoS), especially in millimeter-wave (mmWave) frequencies that use narrow beams. One possible solution is utilizing low-cost and low-complexity metamaterial-based intelligent reflecting surfaces (IRS) to enrich the multipath environment, taking into account that the drones are restricted to fly only within well-defined drone corridors. A hurdle with this solution is placing the IRSs optimally. In this study, we propose an approach for IRS placement with a goal to improve the spatial multiplexing gains, and hence to maximize the average channel capacity in a predefined drone corridor. Our results at 6 GHz, 28 GHz and 60 GHz show that the proposed approach increases the average rates for all frequency bands for a given drone corridor, when compared with the environment where there are no IRSs present, and IRS-aided channels perform close to each other at sub-6 and mmWave bands., Comment: 14 pages, 4 figures, journal article
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- 2021
31. Enrichment of phenotype among biological forms of Anopheles stephensi Liston through establishment of isofemale lines
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Ghosh, Chaitali, Kumar, Naveen, Kushwah, Raja Babu Singh, M., Soumya, Joshi, Soumya Gopal, Ramanjini, Chethan Kumar, Alalamath, Tejashwini, Srinivasan, Subhashini, Subramani, Suresh, Kumar, Sampath, and Swain, Sunita
- Published
- 2023
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32. Radar Cross Section Based Statistical Recognition of UAVs at Microwave Frequencies
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Ezuma, Martins, Anjinappa, Chethan Kumar, Funderburk, Mark, and Guvenc, Ismail
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Electrical Engineering and Systems Science - Signal Processing - Abstract
This paper presents a radar cross-section (RCS)-based statistical recognition system for identifying/ classifying unmanned aerial vehicles (UAVs) at microwave frequencies. First, the paper presents the results of the vertical (VV) and horizontal (HH) polarization RCS measurement of six commercial UAVs at 15 GHz and 25 GHz in a compact range anechoic chamber. The measurement results show that the average RCS of the UAVs depends on shape, size, material composition of the target UAV as well as the azimuth angle, frequency, and polarization of the illuminating radar. Afterward, radar characterization of the target UAVs is achieved by fitting the RCS measurement data to 11 different statistical models. From the model selection analysis, we observe that the lognormal, generalized extreme value, and gamma distributions are most suitable for modeling the RCS of the commercial UAVs while the Gaussian distribution performed relatively poorly. The best UAV radar statistics forms the class conditional probability densities for the proposed UAV statistical recognition system. The performance of the UAV statistical recognition system is evaluated at different signal noise ratio (SNR) with the aid of Monte Carlo analysis. At an SNR of 10 dB, the average classification accuracy of 97.43% or better is achievable., Comment: one column, 39 pages
- Published
- 2021
33. Base Station and Passive Reflectors Placement for Urban mmWave Networks
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Anjinappa, Chethan Kumar, Erden, Fatih, and Guvenc, Ismail
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Electrical Engineering and Systems Science - Signal Processing - Abstract
The use of millimeter-wave (mmWave) bands in 5G networks introduce a new set of challenges to network planning. Vulnerability to blockages and high path loss at mmWave frequencies require careful planning of the network to achieve the desired service quality. In this paper, we propose a novel 3D geometry-based framework for deploying mmWave base stations (gNBs) in urban environments by considering first-order reflection effects. We also provide a solution for the optimum deployment of passive metallic reflectors (PMRs) to extend radio coverage to non-line-of-sight (NLoS) areas. In particular, we perform visibility analysis to find the direct and indirect visibility regions, and using these, we derive a geometry-and-blockage-aided path loss model. We then formulate the network planning problem as two independent optimization problems, placement of gNB(s) and PMRs, to maximize the coverage area with a certain quality-of-service constraint and minimum cost. We test the efficacy of our proposed approach using a generic map and compare our simulation results with the ray-tracing solution. Our simulation results show that considering the first-order reflections in planning the mmWave network helps reduce the number of PMRs required to cover the NLoS area and the gNB placement aided with PMRs requires fewer gNBs to cover the same area, which in turn reduces the deployment cost., Comment: Under review for a possible publication in IEEE Trans. Vehicular Technology, 2020
- Published
- 2020
34. Mismatch Measurement for MIMO mm-Wave Radars via Simple Power Monitors.
- Author
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Ferhat Can Ataman, Mohammed Aladsani, Georgios C. Trichopoulos, Y. B. Chethan Kumar, and Sule Ozev
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- 2023
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35. Global Tuning for System Performance Optimization of RF MIMO Radars.
- Author
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Ferhat Can Ataman, Muslum Emir Avci, Y. B. Chethan Kumar, and Sule Ozev
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- 2023
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36. Improving Angle of Arrival Estimation Accuracy for mm-Wave Radars.
- Author
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Ferhat Can Ataman, Y. B. Chethan Kumar, Sandeep Rao, and Sule Ozev
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- 2023
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37. Signaling Molecules in Medicinal Plants Response to Cold Stress
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Dugganaboyana, Guru Kumar, Shivaramakrishna, Sahana, Kumar, Jajur Ramanna, Velliyur Kanniappan, Gopalakrishnan, Mukunda, Chethan Kumar, Ahalliya, Rathi Muthaiyan, Singh, Divya, editor, Mishra, Amit Kumar, editor, and Srivastava, Akhileshwar Kumar, editor
- Published
- 2023
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38. An SVM-Based Approach for the Quality Estimation of Udupi Jasmine
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Bhat, Sachin S., Nagaraja, Revankar, Suraj, Chethan Kumar, B., Dinesha, Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Noor, Arti, editor, Saroha, Kriti, editor, Pricop, Emil, editor, Sen, Abhijit, editor, and Trivedi, Gaurav, editor
- Published
- 2023
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39. Localization with Deep Neural Networks using mmWave Ray Tracing Simulations
- Author
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Bhattacherjee, Udita, Anjinappa, Chethan Kumar, Smith, LoyCurtis, Ozturk, Ender, and Guvenc, Ismail
- Subjects
Electrical Engineering and Systems Science - Signal Processing - Abstract
The world is moving towards faster data transformation with more efficient localization of a user being the preliminary requirement. This work investigates the use of a deep learning technique for wireless localization, considering both millimeter-wave (mmWave) and sub-6 GHz frequencies. The capability of learning a new neural network model makes the localization process easier and faster. In this study, a Deep Neural Network (DNN) was used to localize User Equipment (UE) in two static scenarios. We propose two different methods to train a neural network, one using channel parameters (features) and another using a channel response vector and compare their performances using preliminary computer simulations. We observe that the former approach produces high localization accuracy considering that all of the users have a fixed number of multipath components (MPCs), this method is reliant on the number of MPCs. On the other hand, the latter approach is independent of the MPCs, but it performs relatively poorly compared to the first approach., Comment: Accepted to IEEE Southeast Conference 2020
- Published
- 2020
40. Off-Grid Aware Spatial Covariance Estimation in mmWave Communications
- Author
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Anjinappa, Chethan Kumar, Gurbuz, Ali Cafer, Yapici, Yavuz, and Guvenc, Ismail
- Subjects
Electrical Engineering and Systems Science - Signal Processing - Abstract
This work investigates the problem of spatial covariance matrix estimation in a millimeter-wave (mmWave) hybrid multiple-input multiple-output (MIMO) system with an emphasis on the basis-mismatch effect. The basis mismatch is prevalent in the compressed sensing (CS) schemes which adopt discretization procedure. In such an approach, the algorithm yields a finite discrete point which is an approximation to the continuous parametric space. The quality of this approximation depends on the number of discretized points in the dictionary. Instead of increasing the number of discretized points to combat this off-grid effect, we propose an efficient parameter perturbed framework which uses a controlled perturbation mechanism in conjunction with the orthogonal matching pursuit (OMP) algorithm. Numerical results verify the performance improvement through our proposed algorithm in terms of relative efficiency metric, which is basically due to taking care of the off-grid effect carefully that is ignored in the conventional CS algorithms., Comment: To appear in 2019 IEEE Asilomar conference on Signals, Systems, and Computers. arXiv admin note: substantial text overlap with arXiv:1907.04423
- Published
- 2019
41. Germination induced changes in bioactive compounds and nutritional components of millets
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Chethan Kumar, Pushpa, Amutha, S., Oberoi, Harinder Singh, Kanchana, S., Azeez, Shamina, and Rupa, T. R.
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- 2022
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42. Detection and Classification of UAVs Using RF Fingerprints in the Presence of Interference
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Ezuma, Martins, Erden, Fatih, Anjinappa, Chethan Kumar, Ozdemir, Ozgur, and Guvenc, Ismail
- Subjects
Electrical Engineering and Systems Science - Signal Processing - Abstract
This paper investigates the problem of detection and classification of unmanned aerial vehicles (UAVs) in the presence of wireless interference signals using a passive radio frequency (RF) surveillance system. The system uses a multistage detector to distinguish signals transmitted by a UAV controller from the background noise and interference signals. First, RF signals from any source are detected using a Markov models-based na\"ive Bayes decision mechanism. When the receiver operates at a signal-to-noise ratio (SNR) of 10 dB, and the threshold, which defines the states of the models, is set at a level 3.5 times the standard deviation of the preprocessed noise data, a detection accuracy of 99.8% with a false alarm rate of 2.8% is achieved. Second, signals from Wi-Fi and Bluetooth emitters, if present, are detected based on the bandwidth and modulation features of the detected RF signal. Once the input signal is identified as a UAV controller signal, it is classified using machine learning (ML) techniques. Fifteen statistical features extracted from the energy transients of the UAV controller signals are fed to neighborhood component analysis (NCA), and the three most significant features are selected. The performance of the NCA and five different ML classifiers are studied for 15 different types of UAV controllers. A classification accuracy of 98.13% is achieved by k-nearest neighbor classifier at 25 dB SNR. Classification performance is also investigated at different SNR levels and for a set of 17 UAV controllers which includes two pairs from the same UAV controller models., Comment: 13 pages. Journal paper. Interference, machine learning, Markov models, RF fingerprinting, unmanned aerial vehicles (UAVs), UAV detection and classification
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- 2019
43. Channel Estimation in mmWave Hybrid MIMO System via Off-Grid Dirichlet Kernels
- Author
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Anjinappa, Chethan Kumar, Zhou, You, Yapici, Yavuz, Baron, Dror, and Guvenc, Ismail
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Electrical Engineering and Systems Science - Signal Processing - Abstract
In this paper, we tackle channel estimation in millimeter-wave hybrid multiple-input multiple-output systems by considering off-grid effects. In particular, we assume that spatial parameters can take any value in the angular domain, and need not fall on predefined discretized angles. Instead of increasing the number of discretized points to combat off-grid effects, we use implicit Dirichlet kernel structure in the Fourier domain, which conventional compressed sensing methods do not use. We propose greedy low-complexity algorithms based on orthogonal matching pursuit (OMP); our core idea is to traverse the Dirichlet kernel peak using estimates of the discrete Fourier transform. We demonstrate the efficacy of our proposed algorithms compared to standard OMP reconstruction. Numerical results show that our proposed algorithms obtain smaller reconstruction errors when off-grid effects are accounted for.
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- 2019
44. Off-Grid Aware Channel and Covariance Estimation in mmWave Networks
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Anjinappa, Chethan Kumar, Gurbuz, Ali Cafer, Yapici, Yavuz, and Guvenc, Ismail
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Electrical Engineering and Systems Science - Signal Processing - Abstract
The spectrum scarcity at sub-6 GHz spectrum has made millimeter-wave (mmWave) frequency band a key component of the next-generation wireless networks. While mmWave spectrum offers extremely large transmission bandwidths to accommodate ever-increasing data rates, unique characteristics of this new spectrum need special consideration to achieve the promised network throughput. In this work, we consider the off-grid problem for mmWave communications, which has a significant impact on basic network functionalities involving beam steering and tracking. The off-grid effect naturally appears in compressed sensing (CS) techniques adopting a discretization approach for representing the angular domain. This approach yields a finite set of discrete angle points, which are an approximation to the continuous angular space, and hence degrade the accuracy of related parameter estimation. In order to cope with the off-grid effect, we present a novel parameter-perturbation framework to efficiently estimate the channel and the covariance for mmWave networks. The proposed algorithms employ a smart perturbation mechanism in conjunction with a low-complexity greedy framework of simultaneous orthogonal matching pursuit (SOMP), and jointly solve for the off-grid parameters and weights. Numerical results show a significant performance improvement through our novel framework as a result of handling the off-grid effects, which is totally ignored in the conventional sparse mmWave channel or covariance estimation algorithms.
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- 2019
45. Joint Frame Synchronization and Channel Estimation: Sparse Recovery Approach and USRP Implementation
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Özdemir, Özgür, Anjinappa, Chethan Kumar, Hamila, Ridha, Al-Dhahir, Naofal, and Güvenç, İsmail
- Subjects
Electrical Engineering and Systems Science - Signal Processing - Abstract
Correlation-based techniques used for frame synchronization can suffer significant performance degradation over multi-path frequency-selective channels. In this paper, we propose a joint frame synchronization and channel estimation (JFSCE) framework as a remedy to this problem. This framework, however, increases the size of the resulting combined channel vector which should capture both the channel impulse response (CIR) vector and the frame boundary offset and, therefore, its estimation becomes more challenging. On the other hand, because the combined channel vector is sparse, sparse channel estimation methods can be applied. We propose several JFSCE methods using popular sparse signal recovery (SSR) algorithms which exploit the sparsity of the combined channel vector. Subsequently, the sparse channel vector estimate is used to design a sparse equalizer. Our simulation results and experimental measurements using software defined radios (SDRs) show that in some scenarios our proposed method improves the overall system performance significantly, in terms of the mean square error (MSE) between the transmitted and the equalized symbols compared to the conventional method., Comment: Accepted to IEEE Access (Mar. 8, 2019). arXiv admin note: text overlap with arXiv:1709.01474
- Published
- 2019
46. Slow Beam Steering and NOMA for Indoor Multi-User Visible Light Communications
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Eroglu, Yusuf Said, Anjinappa, Chethan Kumar, Guvenc, Ismail, and Pala, Nezih
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Electrical Engineering and Systems Science - Signal Processing - Abstract
Visible light communication (VLC) is an emerging technology that enables broadband data rates using the visible spectrum. In this paper, considering slow beam steering where VLC beam directions are assumed to be fixed during a transmission frame, we find the steering angles that simultaneously serve multiple users within the frame duration and maximize the data rates. This is achieved by solving a non-convex optimization problem using a grid-based search and majorization-minimization (MM) procedure. Subsequently, we consider multiple steerable beams with a larger number of users in the network and propose an algorithm to cluster users and serve each cluster with a separate beam. We optimize the transmit power of each beam to maximize the data rates. Finally, we propose a non-orthogonal multiple access (NOMA) scheme for the beam steering and user clustering scenario, to further increase the data rates of the users. The simulation results show that the proposed beam steering method can efficiently serve a high number of users, and with power optimization, a data rate gain up to ten times is possible. The simulation results for NOMA suggests an additional 10 Mbps sum rate gain for each NOMA user pair., Comment: Submitted to IEEE TCOM on Jan 2019
- Published
- 2019
47. Micro-UAV Detection with a Low-Grazing Angle Millimeter Wave Radar
- Author
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Ezuma, Martins, Ozdemir, Ozgur, Anjinappa, Chethan Kumar, Gulzar, Wahab Ali, and Guvenc, Ismail
- Subjects
Electrical Engineering and Systems Science - Signal Processing - Abstract
Millimeter wave radars are popularly used in last-mile radar-based defense systems. Detection of low-altitude airborne target using these radars at low-grazing angles is an important problem in the field of electronic warfare, which becomes challenging due to the significant effects of clutters in the terrain. This paper provides both experimental and analytical investigation of micro unmanned aerial vehicle (UAV) detection in a rocky terrain using a low grazing angle, surface-sited 24 GHz dual polarized frequency modulated continuous wave (FMCW) radar. The radar backscatter signal from the UAV is polluted by land clutters which is modeled using a uniform Weibull distribution. A constant false alarm rate (CFAR) detector which employs adaptive thresholding is designed to detect the UAV in the rich clutter background. In order to further enhance the discrimination of the UAV from the clutter, the micro-Doppler signature of the rotating propellers and bulk trajectory of the UAV are extracted and plotted in the time-frequency domain.
- Published
- 2019
48. Micro-UAV Detection and Classification from RF Fingerprints Using Machine Learning Techniques
- Author
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Ezuma, Martins, Erden, Fatih, Anjinappa, Chethan Kumar, Ozdemir, Ozgur, and Guvenc, Ismail
- Subjects
Electrical Engineering and Systems Science - Signal Processing - Abstract
This paper focuses on the detection and classification of micro-unmanned aerial vehicles (UAVs) using radio frequency (RF) fingerprints of the signals transmitted from the controller to the micro-UAV. In the detection phase, raw signals are split into frames and transformed into the wavelet domain. A Markov models-based naive Bayes approach is used to check for the presence of a UAV in each frame. In the classification phase, unlike the traditional approaches that rely solely on time-domain signals and corresponding features, the proposed technique uses the energy transient signal. This approach is more robust to noise and can cope with different modulation techniques. First, the normalized energy trajectory is generated from the energy-time-frequency distribution of the raw control signal. Next, the start and end points of the energy transient are detected by searching for the most abrupt changes in the mean of the energy trajectory. Then, a set of statistical features is extracted from the energy transient. Significant features are selected by performing neighborhood component analysis (NCA) to keep the computational cost of the algorithm low. Finally, selected features are fed to several machine learning algorithms for classification. The algorithms are evaluated experimentally using a database containing 100 RF signals from each of 14 different UAV controllers. The signals are recorded wirelessly using a high-frequency oscilloscope. The data set is randomly partitioned into training and test sets for validation with the ratio 4:1. Ten Monte Carlo simulations are run and results are averaged to assess the performance of the methods. All the micro-UAVs are detected correctly and an average accuracy of 96.3% is achieved using the k-nearest neighbor (kNN) classification. Proposed methods are also tested for different signal-to-noise ratio (SNR) levels and results are reported., Comment: 12 pages. To be presented in 2019 IEEE Aerospace Conference
- Published
- 2019
49. Ray Tracing Analysis of Sub-6 GHz and mmWave Indoor Coverage with Reflecting Surfaces.
- Author
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Ender Ozturk, Fatih Erden, Kairui Du, Chethan Kumar Anjinappa, özgür özdemir, and Ismail Güvenç
- Published
- 2022
- Full Text
- View/download PDF
50. Optimal Design of Energy-Harvesting Hybrid VLC/RF Networks.
- Author
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Amir Hossein Fahim Raouf, Chethan Kumar Anjinappa, and Ismail Güvenç
- Published
- 2022
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