Search results for: radio frequency (RF)

Authors: Hsin-Yi Lo, Chia-Yu Hsu

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This article is the nursing experience of a multiple trauma case using Swanson's theory of caring, the nursing period is from May 31 to June 4, 2021, collect data through observation, written talks, interviews, listening, direct care and physical assessment, established cases with health problems such as acute pain, impaired tissue integrity, and anxiety. Nursing process including, evaluate the pain index with the pain assessment scale, assist in acupoint massage, use a corset to fix the wound, and give the patient listening to favorite radio programs to divert attention and relieve pain problems; promote wound healing and avoid infection by assessing wound condition and exudation, changing dressings with aseptic technique, and providing appropriate dressings; encourage patients to express their feelings, provide companionship, and assist in self-care and participation in treatment plans, to enable the case to overcome the anxiety caused by being admitted to the intensive care unit for the first time and not knowing about the disease, and assist the case to overcome the injury caused by the accident and return to normal life. There is no video equipment in the intensive care unit during the nursing period. In response to the problem that family visits cannot be opened during the epidemic, it is a limitation this time. It is recommended that the hospital take this into consideration in the future. In the post-epidemic era, it can reduce the risk of various infections for patients and family members. Traveling between home and hospital, improving the quality of high-quality and technological care.

Keywords: swanson's theory of caring, multiple trauma, anxiety, nursing experience

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Authors: Shimeles Terefe Mengistue, Paola Marziani, Ascensióndel Olmo, Jaime Perea, Mirjana Pović

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The theory that rotating accretion disks are responsible for the broad emission-line profiles in quasars is frequently put forth; however, the presence of accretion disk (AD) in active galactic nuclei (AGN) had limited and indirect observational support. In order to evaluate the extent to which the AD is a source of the broad Balmer lines and high ionization UV lines in radio-loud (RL) AGN, we focused on an extremely jetted RL quasar, 3C 47 that clearly shows a double peaked profile. This work presents its optical spectra and UV observations from the HST/FOS covering the rest-frame spectral range from 2000 to 7000 \AA. The fit of the low ionization lines, Hbeta, Halpha and MgII2800 show profiles that are in very good agreement with a relativistic Keplerian AD model. The profile of the prototypical high ionization lines can also be modeled by the contribution of the AD, with additional components due to outflows and emissions from the innermost part of the narrow line regions (NLRs). A prominent fit of the resulting double peaked profiles were found and very important disk parameters of the disk have been determined using the Hbeta, Halpha and MgII2800 lines: the inner and outer radii (both in units of G/mbh, where mbh is the supermassive black hole), an inclination to the line of sight, the emissivity index and the local broadening parameter. In addition, the accretion parameters, /mbh and /lledd are also determined. This work indicates that the line profile of 3C 47 shows the most convincing direct evidence for the presence of a rotating AD in AGN and the broad, double-peaked profiles originate from this AD that surrounds an /mbh.

Keywords: active galactic nuclei, quasars, emission lines, Double-peaked, supermassive black hole

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Authors: Ahmet Karagoz, Irfan Karagoz

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Synthetic Aperture Radar (SAR) is a radar mechanism that can be integrated into manned and unmanned aerial vehicles to create high-resolution images in all weather conditions, regardless of day and night. In this study, SAR images of military vehicles with different azimuth and descent angles are pre-processed at the first stage. The main purpose here is to reduce the high speckle noise found in SAR images. For this, the Wiener adaptive filter, the mean filter, and the median filters are used to reduce the amount of speckle noise in the images without causing loss of data. During the image segmentation phase, pixel values are ordered so that the target vehicle region is separated from other regions containing unnecessary information. The target image is parsed with the brightest 20% pixel value of 255 and the other pixel values of 0. In addition, by using appropriate parameters of statistical region merging algorithm, segmentation comparison is performed. In the step of feature extraction, the feature vectors belonging to the vehicles are obtained by using Gabor filters with different orientation, frequency and angle values. A number of Gabor filters are created by changing the orientation, frequency and angle parameters of the Gabor filters to extract important features of the images that form the distinctive parts. Finally, images are classified by sparse representation method. In the study, l₁ norm analysis of sparse representation is used. A joint database of the feature vectors generated by the target images of military vehicle types is obtained side by side and this database is transformed into the matrix form. In order to classify the vehicles in a similar way, the test images of each vehicle is converted to the vector form and l₁ norm analysis of the sparse representation method is applied through the existing database matrix form. As a result, correct recognition has been performed by matching the target images of military vehicles with the test images by means of the sparse representation method. 97% classification success of SAR images of different military vehicle types is obtained.

Keywords: automatic target recognition, sparse representation, image classification, SAR images

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Authors: Robert Lenzie

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Transcranial electrical stimulation (tES) is significant in the research literature. However, the effects of tES on brain activity are still poorly understood at the surface level, the Brodmann Area level, and the impact on neural networks. Using a method like electroencephalography (EEG) in conjunction with tES might make it possible to comprehend the brain response and mechanisms behind published observed alterations in more depth. Using a method to directly see the effect of tES on EEG may offer high temporal resolution data on the brain activity changes/modulations brought on by tES that correlate to various processing stages within the brain. This paper provides unpublished information on a cutting-edge methodology that may reveal details about the dynamics of how the human brain works beyond what is now achievable with existing methods.

Keywords: tACS, frequency, EEG, optimal

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Authors: Chayma Bahar, Chokri Baccouch, Hedi Sakli, Nizar Sakli

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Harvesting and transport of optical and radiofrequency signals are a topical subject with multiple challenges. In this paper, we present a Optical RECTENNA system. We propose here a hybrid system solar cell antenna for 5G mobile communications networks. Thus, we propose rectifying circuit. A parametric study is done to follow the influence of load resistance and input power on Optical RECTENNA system performance. Thus, we propose a solar cell antenna structure in the frequency band of future 5G standard in 2.45 GHz bands.

Keywords: antenna, IoT, optical rectenna, solar cell

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Authors: Zulkifli Zainal Abidin, Ahmad Shahril Mohd Ghani

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Agent-based systems technology has been addressed as a new paradigm for conceptualizing, designing, and implementing software systems. Agents are sophisticated systems that act autonomously across open and distributed environments in solving problems. Nevertheless, it is impractical to rely on a single agent to do all computing processes in solving complex problems. An increasing number of applications lately require multiple agents to work together. A multi-agent system (MAS) is a loosely coupled network of agents that interact to solve problems that are beyond the individual capacities or knowledge of each problem solver. However, the network of MAS still requires a main system to govern or oversees the operation of the agents in order to achieve a unified goal. We had developed a fleet management system (FMS) in order to manage the fleet of agents, plan route for the agents, perform real-time data processing and analysis, and issue sets of general and specific instructions to the agents. This FMS should be able to perform real-time data processing, communicate with the autonomous surface vehicle (ASV) agents and generate bathymetric map according to the data received from each ASV unit. The first algorithm is developed to communicate with the ASV via radio communication using standard National Marine Electronics Association (NMEA) protocol sentences. Next, the second algorithm will take care of the path planning, formation and pattern generation is tested using various sample data. Lastly, the bathymetry map generation algorithm will make use of data collected by the agents to create bathymetry map in real-time. The outcome of this research is expected can be applied on various other multi-agent systems.

Keywords: autonomous surface vehicle, fleet management system, multi agent system, bathymetry

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Authors: Natalia Polkanova, Sergey Kazakov

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In the research, we proposed the set of factors of tourist destinations attractiveness in Spain and determined the factors that have the greatest impact on the positive perception of the tourist destination by Russian tourists; also, we examined what factors create the willingness for Russians to recommend this tourist destination to their friends and relatives. The tourists' comments on the Russian travel sites have been analyzed in order to determine the frequency of attractiveness characteristics references. Additionally, the study will reflect the relationship of variables.

Keywords: tourism destination, destination attractiveness, destination competitiveness, content analysis, unstructured image

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Authors: Gayani Ranawake

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Effective communication is widely regarded as an important aspect of any discipline. This particular study deals with written communication in science. Writing conventions and linguistic choices play a key role in conveying the message effectively to a target audience. Scientists are responsible for conveying their findings or research results not only to their discourse community but also to the general public. Recognizing appropriate linguistic choices is crucial since they vary depending on the target audience. The majority of scientists can communicate effectively with their discourse community, but public engagement seems more challenging to them. There is a lack of research into the language use of scientists, and in particular how it varies by discipline and audience (genre). A better understanding of the different linguistic conventions used in effective science writing by scientists for scientists and by scientists for the public will help to guide scientists who are familiar with their discourse community norms to write effectively for the public. This study investigates the differences and similarities of linguistic choices in biology articles written by scientists for their discourse community and biology magazine articles written by scientists and science communicators for the general public. This study is a part of a larger project investigating linguistic differences in different genres of science academic writing. The sample for this particular study is composed of 20 research articles from the journal Biological Reviews and 20 magazine articles from the magazine Australian Popular Science. Differences in the linguistic devices were analyzed using Hyland’s metadiscourse model for academic writing proposed in 2005. The frequency of the usage of interactive resources (transitions, frame markers, endophoric markers, evidentials and code glosses) and interactional resources (hedges, boosters, attitude markers, self-mentions and engagement markers) were compared and contrasted using the NVivo textual analysis tool. The results clearly show the differences in the frequency of usage of interactional and interactive resources in the two disciplines under investigation. The findings of this study provide a reference guide for scientists and science writers to understand the differences in the linguistic choices between the two genres. This will be particularly helpful for scientists who are proficient at writing for their discourse community, but not for the public.

Keywords: discourse analysis, linguistic choices, metadiscourse, science writing

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Authors: Ben Soltane Cheima, Ittansa Yonas Kelbesa

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Speaker Identification (SI) is the task of establishing identity of an individual based on his/her voice characteristics. The SI task is typically achieved by two-stage signal processing: training and testing. The training process calculates speaker specific feature parameters from the speech and generates speaker models accordingly. In the testing phase, speech samples from unknown speakers are compared with the models and classified. Even though performance of speaker identification systems has improved due to recent advances in speech processing techniques, there is still need of improvement. In this paper, a Closed-Set Tex-Independent Speaker Identification System (CISI) based on a Multiple Classifier System (MCS) is proposed, using Mel Frequency Cepstrum Coefficient (MFCC) as feature extraction and suitable combination of vector quantization (VQ) and Gaussian Mixture Model (GMM) together with Expectation Maximization algorithm (EM) for speaker modeling. The use of Voice Activity Detector (VAD) with a hybrid approach based on Short Time Energy (STE) and Statistical Modeling of Background Noise in the pre-processing step of the feature extraction yields a better and more robust automatic speaker identification system. Also investigation of Linde-Buzo-Gray (LBG) clustering algorithm for initialization of GMM, for estimating the underlying parameters, in the EM step improved the convergence rate and systems performance. It also uses relative index as confidence measures in case of contradiction in identification process by GMM and VQ as well. Simulation results carried out on voxforge.org speech database using MATLAB highlight the efficacy of the proposed method compared to earlier work.

Keywords: feature extraction, speaker modeling, feature matching, Mel frequency cepstrum coefficient (MFCC), Gaussian mixture model (GMM), vector quantization (VQ), Linde-Buzo-Gray (LBG), expectation maximization (EM), pre-processing, voice activity detection (VAD), short time energy (STE), background noise statistical modeling, closed-set tex-independent speaker identification system (CISI)

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Authors: Lise Paesen, Marielle Leijten

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People diagnosed with probable Alzheimer disease suffer from an impairment of their language capacities; a gradual impairment which affects both their spoken and written communication. Our study aims at characterising the language decline in DAT patients with the use of congeneric elicited writing tasks. Within these tasks, a descriptive text has to be written based upon images with which the participants are confronted. A randomised set of images allows us to present the participants with a different task on every encounter, thus allowing us to avoid a recognition effect in this iterative study. This method is a revision from previous studies, in which participants were presented with a larger picture depicting an entire scene. In order to create the randomised set of images, existing pictures were adapted following strict criteria (e.g. frequency, AoA, colour, ...). The resulting data set contained 50 images, belonging to several categories (vehicles, animals, humans, and objects). A pre-test was constructed to validate the created picture set; most images had been used before in spoken picture naming tasks. Hence the same reaction times ought to be triggered in the typed picture naming task. Once validated, the effectiveness of the descriptive tasks was assessed. First, the participants (n=60 students, n=40 healthy elderly) performed a typing task, which provided information about the typing speed of each individual. Secondly, two descriptive writing tasks were carried out, one simple and one complex. The simple task contains 4 images (1 animal, 2 objects, 1 vehicle) and only contains elements with high frequency, a young AoA (<6 years), and fast reaction times. Slow reaction times, a later AoA (≥ 6 years) and low frequency were criteria for the complex task. This task uses 6 images (2 animals, 1 human, 2 objects and 1 vehicle). The data were collected with the keystroke logging programme Inputlog. Keystroke logging tools log and time stamp keystroke activity to reconstruct and describe text production processes. The data were analysed using a selection of writing process and product variables, such as general writing process measures, detailed pause analysis, linguistic analysis, and text length. As a covariate, the intrapersonal interkey transition times from the typing task were taken into account. The pre-test indicated that the new images lead to similar or even faster reaction times compared to the original images. All the images were therefore used in the main study. The produced texts of the description tasks were significantly longer compared to previous studies, providing sufficient text and process data for analyses. Preliminary analysis shows that the amount of words produced differed significantly between the healthy elderly and the students, as did the mean length of production bursts, even though both groups needed the same time to produce their texts. However, the elderly took significantly more time to produce the complex task than the simple task. Nevertheless, the amount of words per minute remained comparable between simple and complex. The pauses within and before words varied, even when taking personal typing abilities (obtained by the typing task) into account.

Keywords: Alzheimer's disease, experimental design, language decline, writing process

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Authors: Tri Wijayanti Septiarini, Agus Maman Abadi, Muhammad Rifki Taufik

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The exchange rate of IDR/USD can be the indicator to analysis Indonesian economy. The exchange rate as a important factor because it has big effect in Indonesian economy overall. So, it needs the analysis data of exchange rate. There is decomposition data of exchange rate of IDR/USD to be frequency and time. It can help the government to monitor the Indonesian economy. This method is very effective to identify the case, have high accurate result and have simple structure. In this paper, data of exchange rate that used is weekly data from December 17, 2010 until November 11, 2014.

Keywords: the exchange rate, fuzzy mamdani, discrete wavelet transforms, fuzzy wavelet

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Authors: B. H. Lee

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Nowadays, a grid-connected photovoltaic (PV) inverter is adopted in various places like as home, factory, because grid-connected PV inverter can reduce total power consumption by supplying electricity from PV array. In this paper, design and implementation of a 300 W grid-connected PV inverter are described. It is implemented with TI Piccolo DSP core and operated at 100 kHz switching frequency in order to reduce harmonic contents. The maximum operating input voltage is up to 45 V. The characteristics of the designed system that include maximum power point tracking (MPPT), single operation and battery charging are verified by simulation and experimental results.

Keywords: design, grid-connected, implementation, photovoltaic

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Authors: Ola A. Nassr, Ali M. Abd Alridha, Rua A. Naser, Rasha S. Abbas

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Background: Excessive and inappropriate use of antimicrobial agents among hospitalized patients remains an important patient safety and public health issue worldwide. Not only does this behavior incur unnecessary cost but it is also associated with increased morbidity and mortality. The objective of this study is to obtain an insight into the prescribing patterns of antibiotics in surgical and medical wards, to help identify a scope for improvement in service delivery. Method: A simple point prevalence survey included a convenience sample of 200 patients admitted to medical and surgical wards in a government teaching hospital in Baghdad between October 2017 and April 2018. Data were collected by a trained pharmacy intern using a standardized form. Patient’s demographics and details of the prescribed antibiotics, including dose, frequency of dosing and route of administration, were reported. Patients were included if they had been admitted at least 24 hours before the survey. Patients under 18 years of age, having a diagnosis of cancer or shock, or being admitted to the intensive care unit, were excluded. Data were checked and entered by the authors into Excel and were subjected to frequency analysis, which was carried out on anonymized data to protect patient confidentiality. Results: Overall, 88.5% of patients (n=177) received 293 antibiotics during their hospital admission, with a small variation between wards (80%-97%). The average number of antibiotics prescribed per patient was 1.65, ranging from 1.3 for medical patients to 1.95 for surgical patients. Parenteral third-generation cephalosporins were the most commonly prescribed at a rate of 54.3% (n=159) followed by nitroimidazole 29.4% (n=86), quinolones 7.5% (n=22) and macrolides 4.4% (n=13), while carbapenems and aminoglycosides were the least prescribed together accounting for only 4.4% (n=13). The intravenous route was the most common route of administration, used for 96.6% of patients (n=171). Indications were reported in only 63.8% of cases. Culture to identify pathogenic organisms was employed in only 0.5% of cases. Conclusion: Broad-spectrum antibiotics are prescribed at an alarming rate. This practice may provoke antibiotic resistance and adversely affect the patient outcome. Implementation of an antibiotic stewardship program is warranted to enhance the efficacy, safety and cost-effectiveness of antimicrobial agents.

Keywords: Acute care, Antibiotic misuse, Iraq, Prescribing

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Authors: Jae-Hyun Ro, Yong-Jun Kim, Chang-Bin Ha, Hyoung-Kyu Song

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In multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) systems, many detection schemes have been developed to improve the error performance and to reduce the complexity. Maximum likelihood (ML) detection has optimal error performance but it has very high complexity. Thus, this paper proposes reduced complexity of ML detection combined with decision feedback equalizer (DFE). The error performance of the proposed detection scheme is higher than the conventional DFE. But the complexity of the proposed scheme is lower than the conventional ML detection.

Keywords: detection, DFE, MIMO-OFDM, ML

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Authors: Othman Y. Alothman

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The study aims to investigate the effects of blend ratio, VA content and temperature on the rheological properties of PPEVA blends. The results show that all pure polymers and their blends show typical shear thinning behaviour. All neat polymers exhibit power-low type flow behaviour, with the viscosity order as EVA328 > EVA206 > PP in almost all frequency ranges. As temperature increases, the viscosity of all polymers decreases as expected, and the viscosity becomes more sensitive to the addition of EVA. Two different regions can be observed on the flow curve of some of the polymers and their blends, which is thought to be due to slip-stick transition or melt fracture.

Keywords: polypropylene, ethylene vinyl acetate, blends, rheological properties

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Authors: Thomas Bryan, Veton Kepuska, Ivica Kostanic

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Speaker recognition is performed in high Additive White Gaussian Noise (AWGN) environments using principals of Computational Auditory Scene Analysis (CASA). CASA methods often classify sounds from images in the time-frequency (T-F) plane using spectrograms or cochleargrams as the image. In this paper atomic decomposition implemented by matching pursuit performs a transform from time series speech signals to the T-F plane. The atomic decomposition creates a sparsely populated T-F vector in “weight space” where each populated T-F position contains an amplitude weight. The weight space vector along with the atomic dictionary represents a denoised, compressed version of the original signal. The arraignment or of the atomic indices in the T-F vector are used for classification. Unsupervised feature learning implemented by a sparse autoencoder learns a single dictionary of basis features from a collection of envelope samples from all speakers. The approach is demonstrated using pairs of speakers from the TIMIT data set. Pairs of speakers are selected randomly from a single district. Each speak has 10 sentences. Two are used for training and 8 for testing. Atomic index probabilities are created for each training sentence and also for each test sentence. Classification is performed by finding the lowest Euclidean distance between then probabilities from the training sentences and the test sentences. Training is done at a 30dB Signal-to-Noise Ratio (SNR). Testing is performed at SNR’s of 0 dB, 5 dB, 10 dB and 30dB. The algorithm has a baseline classification accuracy of ~93% averaged over 10 pairs of speakers from the TIMIT data set. The baseline accuracy is attributable to short sequences of training and test data as well as the overall simplicity of the classification algorithm. The accuracy is not affected by AWGN and produces ~93% accuracy at 0dB SNR.

Keywords: time-frequency plane, atomic decomposition, envelope sampling, Gabor atoms, matching pursuit, sparse dictionary learning, sparse autoencoder

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Authors: Mehtap Çalışkan, Nilüfer Yıldız Varan, Volkan Kaplan

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In this study, the effects of an atmospheric plasma treatment on the durability of water and oil repellent finishes of PET and PET/Spandex fabrics were tested. Fabrics were treated with a low-frequency atmospheric pressure glow discharge. After plasma treatments, the water and oil repellent finishes were applied using pad-dry-cure method. It was observed that plasma treatments improved the durability finish for all fabrics.

Keywords: atmospheric plasma, durable coating, oil repellency, PET/spandex fabrics, water repellency

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Authors: Mahabub Alam, Mohammad Mahmudul Hassan, M. Hasanuzzaman, M. Ahasanul Hoque

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Animals are transported from one place to another for different purposes in Bangladesh. However, the potential effect of long-distance transport on cattle health has not frequently been studied. Therefore, this study was conducted to assess health conditions of cattle transported from a long distance to Chittagong in Bangladesh. A total of 100 adult cattle, regardless of breed and sex, were selected at Benapole live cattle market in Jessore between August and September 2015 for the study. Blood samples were taken from 50 randomly selected cattle at 0 hours before transportation, just after transportation, at 12-16 hours post-conclusion of transportation, and 24 hours after transportation. The external health conditions and injuries of the cattle were assessed by close inspection, and the trader was interviewed using the structured questionnaire. Images of cattle injuries were taken with a camera. The basic internal health of the cattle was evaluated using standard hemato-biochemical tests. Animals were fasted and remained standing within a small space allocation (8-10 sq feet/animal) in the vehicle during transportation. Animals were provided only with paddy straw and water prior to selling at the destination market. The overall frequency of cattle injuries varied significantly (26% before vs. 47% after transportation; p < 0.001). The frequency of different cattle injuries also significantly varied by types such as abrasion (11% vs. 21%; p < 0.05) and barbed wire injury (9% vs. 18%; p < 0.05). Single cattle injury differed significantly (21% vs. 36%; p < 0.001). Cattle health conditions varied significantly (nasal discharge: 15% vs. 28%; p < 0.05; diarrhea: 15% vs. 23%; p < 0.05 and severe dehydration: 8% vs. 20%; p < 0.001). The values of hemoglobin (Hb), total erythrocyte count (TEC), total leukocyte count (TLC), lymphocyte (L), neutrophil (N) and eosinophil (E) varied significantly (p ≤ 0.01) (Hb: 11.1mg/dl vs. 12.3mg/dl; TEC: 4.7 million/ml vs. 5.7million/ml; TLC: 6.2 thousand/ml vs. 7.3 thousand/ml; L: 61.7% vs. 58.1%; N: 29.7% vs. 32.8%; E: 3.8% vs. 4.7%). The values of serum total protein (TP), creatine kinase (CK), triglyceride (TG), calcium (Ca), phosphorus (P) and alkaline phosphatase (ALP) significantly differed (p ≤ 0.05) (TP: 6.8g/dl vs. 8.2g/dl; CK:574.9u/l vs. 1288u/l; TG: 104.7mg/dl vs. 127.7mg/dl; Ca: 11.3mg/dl vs. 13mg/dl; P: 7.3mg/dl vs. 7.6mg/dl; ALP: 303u/l vs. 363u/l). The identified status of external and internal health conditions of the cattle for trading purpose due to long-distance transportation in the present study indicates a high degree of transport stress and poor animal welfare.

Keywords: animal welfare, cattle, external and internal health conditions, transportation

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Authors: Mihretu Erjabo

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Halaba special district is characterized by drought, soil erosion, high population pressure, poor livestock production, lack of feed for livestock, very deep water table, very low productivity of crops and food insufficiency. In order to address these problems, the woreda agricultural development office along with other management practices such as soil physical conservation measures agroforestry was introduced decades ago as a means to alleviate the problem. However, the level of agroforestry adoption remains low. Objective of this study was to identify the factors that influence adoption of agroforestry technologies by farmers in the district. Random sampling was employed to select two kebele administrations and respondents. Data collection was conducted by rural household questionnaire survey, participatory rural appraisal, questionnaires for local and woreda extension staff, secondary data resources and field observation. A sample of 12 key informants, 6 extension staffs, and 182 households, were used in the data collection. Chi square test used to determine significant relationships between adoption of agroforestry and 15 selected variables. Out of which eleven were found to be significant to affect farmers’ adoptiveness. These were frequency of visits of farmers (13.39%), participation in training (11.49%), farmers’ attitude towards agroforestry practices (10.61%), frequency of visits of extensionists (10.38%), participation in extension meeting (10.34%), participation in field day (10.28%), land holding size (9.29%), level of literacy (8.78%), awareness about the importance of agroforestry technology packages (7.06%), time taken from their residence to nearest extension (5.04%) and gender of respondents (3.34%). This study also identified various factors that result in low adoption rates of agroforestry including fear of competition, seedling, rainfall and labour shortage, free grazing, financial problem, expecting trees as soil degrader and long span of trees and lack of need ranking. To improve farmers’ adoption, the factors identified should be well addressed by launching a series and recurrent outreach extension program appropriate and suitable to farmers need.

Keywords: farmers attitude, farmers participation, soil degradation, technology packages

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Authors: Sylvester Akpah, Selasi Vondee

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Unmanned Aerial Vehicles (UAV) as they are also known, drones have attracted increasing attention in recent years due to their ubiquitous nature and boundless applications in the areas of communication, surveying, aerial photography, weather forecasting, medical delivery, surveillance amongst others. Operated remotely in real-time or pre-programmed, drones can fly autonomously or on pre-defined routes. The application of these aerial vehicles has successfully penetrated the world due to technological evolution, thus a lot more businesses are utilizing their capabilities. Unfortunately, while drones are replete with the benefits stated supra, they are riddled with some problems, mainly attributed to the complexities in learning how to master drone flights, collision avoidance and enterprise security. Additional challenges, such as the analysis of flight data recorded by sensors attached to the drone may take time and require expert help to analyse and understand. This paper presents an autonomous drone control system using a chatbot. The system allows for easy control of drones using conversations with the aid of Natural Language Processing, thus to reduce the workload needed to set up, deploy, control, and monitor drone flight missions. The results obtained at the end of the study revealed that the drone connected to the chatbot was able to initiate flight missions with just text and voice commands, enable conversation and give real-time feedback from data and requests made to the chatbot. The results further revealed that the system was able to process natural language and produced human-like conversational abilities using Artificial Intelligence (Natural Language Understanding). It is recommended that radio signal adapters be used instead of wireless connections thus to increase the range of communication with the aerial vehicle.

Keywords: artificial ntelligence, chatbot, natural language processing, unmanned aerial vehicle

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Authors: Ajith Kumar S., Sankaran Namboothiri, Sankrish J., SarathKumar S., S. Anil Lal

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A numerical analysis of flow over a heated circular cylinder is done in this paper. The governing equations, Navier-Stokes, and energy equation within the Boussinesq approximation along with continuity equation are solved using hybrid FEM-FVM technique. The density gradient created due to the heating of the cylinder will induce buoyancy force, opposite to the direction of action of acceleration due to gravity, g. In the present work, the flow direction and the direction of buoyancy force are taken as same (vertical flow configuration), so that the buoyancy force accelerates the mean flow past the cylinder. The relative dominance of the buoyancy force over the inertia force is characterized by the Richardson number (Ri), which is one of the parameter that governs the flow dynamics and heat transfer in this analysis. It is well known that above a certain value of Reynolds number, Re (ratio of inertia force over the viscous forces), the unsteady Von Karman vortices can be seen shedding behind the cylinder. The shedding wake patterns could be seriously altered by heating/cooling the cylinder. The non-dimensional shedding frequency called the Strouhal number is found to be increasing as Ri increases. The aerodynamic force coefficients CL and CD are observed to change its value. In the present vertical configuration of flow over the cylinder, as Ri increases, shedding frequency gets increased and suddenly drops down to zero at a critical value of Richardson number. The unsteady vortices turn to steady standing recirculation bubbles behind the cylinder after this critical Richardson number. This phenomenon is well known in literature as "Breakdown of the Karman Vortex Street". It is interesting to see the flow structures on further increase in the Richardson number. On further heating of the cylinder surface, the size of the recirculation bubble decreases without loosing its symmetry about the horizontal axis passing through the center of the cylinder. The separation angle is found to be decreasing with Ri. Finally, we observed a second critical Richardson number, after which the the flow will be attached to the cylinder surface without any wake behind it. The flow structures will be symmetrical not only about the horizontal axis, but also with the vertical axis passing through the center of the cylinder. At this stage, there will be a "single plume" emanating from the rear stagnation point of the cylinder. We also observed the transition of the plume is a strong function of the Richardson number.

Keywords: drag reduction, flow over circular cylinder, flow control, mixed convection flow, vortex shedding, vortex breakdown

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Authors: Mei Xuan Tan, Eng Ying Bong

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Academic discussion during and after instructional teaching is an integral part of learning. Such discussion between the instructor and student or peer-to-peer discussion can be in several different forms. It could be face-to-face discussion, via email and use of online discussion forum. In this study, the effectiveness of using WhatsApp for academic discussion for a first year half-credit Chemistry course was examined. This study was run over two years with two different batches of students. Participation in the study was voluntary and student volunteers were recruited within the first week of the term. The activity in the WhatsApp group was monitored by two instructors teaching the course. At the end of the course, the students participated in an online survey to evaluate their experience of using WhatsApp for academic discussion. There were a total of 26 questions. The survey had a total of 4 sections with regards to the use of WhatsApp for academic discussion: 1) Familiarity with WhatsApp, 2) Effectiveness of using WhatsApp for discussion, 3) Challenges and 4) Overall experience. The main purpose of using an IM platform for academic discussion was to encourage after-class discussion amongst the students. 32% of the participants had used other online platform, such as Piazza and forums in Learning Management System (LMS), for after-class academic discussion with their instructors and peers. This was a low percentage considering that some courses use such online platform as their main forum amongst instructors and students. At the end of our study, over 83% of the participants felt that WhatsApp was a more effective platform compared to other online forum. One interesting finding was the effect of WhatsApp discussion on face-to-face interaction with instructors. 28% of the students agreed that the use of WhatsApp as a discussion forum had encouraged them to approach their instructors during or after class. 51% of students answered neutral. This could be interpreted that the use of WhatsApp had not affected the frequent (or lack of) face-to-face interaction with their instructors. A second survey question, similar but phrased differently from the first, was also asked to evaluate the aspect of face-to-face interaction with instructors. 34% disagreed that the use of WhatsApp had reduced the frequency of face-to-face interaction. This could imply that the frequency remained the same or might have increased. The 38% who agreed to a decrease in face-to-face interaction have either asked the questions in WhatsApp or had their questions answered by a query from another student in the group chat. These outcomes suggested that the use of technology aided and complemented face-to-face interaction between instructors and students. The study also looked at the challenges of using WhatsApp for academic discussion. Some challenges included difficulty in referring back to previous discussion and students finding some discussions irrelevant to them. In conclusion, the use of IM platform for academic discussion was desirable for the students, but it should not be the only channel as face-to-face consultation and online forum for lengthy discussion are still important for after-class learning of students.

Keywords: chemistry, pedogogy, technological tools, undergraduate

Procedia PDF Downloads 132

Authors: Philipp Wenger, Michael Beltle, Stefan Tenbohlen, Uwe Riechert

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The integration of renewable energy introduces new challenges to the transmission grid, as the power generation is located far from load centers. The associated necessary long-range power transmission increases the demand for high voltage direct current (HVDC) transmission lines and DC distribution grids. HVDC gas-insulated switchgears (GIS) are considered being a key technology, due to the combination of the DC technology and the long operation experiences of AC-GIS. To ensure long-term reliability of such systems, insulation defects must be detected in an early stage. Operational experience with AC systems has proven evidence, that most failures, which can be attributed to breakdowns of the insulation system, can be detected and identified via partial discharge (PD) measurements beforehand. In AC systems the identification of defects relies on the phase resolved partial discharge pattern (PRPD). Since there is no phase information within DC systems this method cannot be transferred to DC PD diagnostic. Furthermore, the behaviour of e.g. free-moving particles differs significantly at DC: Under the influence of a constant direct electric field, charge carriers can accumulate on particles’ surfaces. As a result, a particle can lift-off, oscillate between the inner conductor and the enclosure or rapidly bounces at just one electrode, which is known as firefly motion. Depending on the motion and the relative position of the particle to the electrodes, broadband electromagnetic PD pulses are emitted, which can be recorded by ultra-high frequency (UHF) measuring methods. PDs are often accompanied by light emissions at the particle’s tip which enables optical detection. This contribution investigates PD characteristics of free moving metallic particles in a commercially available 300 kV SF6-insulated HVDC-GIS. The influences of various defect parameters on the particle motion and the PD characteristic are evaluated experimentally. Several particle geometries, such as cylinder, lamella, spiral and sphere with different length, diameter and weight are determined. The applied DC voltage is increased stepwise from inception voltage up to UDC = ± 400 kV. Different physical detection methods are used simultaneously in a time-synchronized setup. Firstly, the electromagnetic waves emitted by the particle are recorded by an UHF measuring system. Secondly, a photomultiplier tube (PMT) detects light emission with a wavelength in the range of λ = 185…870 nm. Thirdly, a high-speed camera (HSC) tracks the particle’s motion trajectory with high accuracy. Furthermore, an electrically insulated electrode is attached to the grounded enclosure and connected to a current shunt in order to detect low frequency ion currents: The shunt measuring system’s sensitivity is in the range of 10 nA at a measuring bandwidth of bw = DC…1 MHz. Currents of charge carriers, which are generated at the particle’s tip migrate through the gas gap to the electrode and can be recorded by the current shunt. All recorded PD signals are analyzed in order to identify characteristic properties of different particles. This includes e.g. repetition rates and amplitudes of successive pulses, characteristic frequency ranges and detected signal energy of single PD pulses. Concluding, an advanced understanding of underlying physical phenomena particle motion in direct electric field can be derived.

Keywords: current shunt, free moving particles, high-speed imaging, HVDC-GIS, UHF

Procedia PDF Downloads 149

Authors: Sanjay Kumar Srivastava, Anu Rani Sharma, Kamna Sachdeva

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Every year, fog formation over the Indo-Gangetic Plains (IGPs) of Indian region during the winter months of December and January is believed to create numerous hazards, inconvenience, and economic loss to the inhabitants of this densely populated region of Indian subcontinent. The aim of the paper is to analyze the spatial and temporal variability of winter fog over IGPs. Long term ground observations of visibility and other meteorological parameters (1971-2010) have been analyzed to understand the formation of fog phenomena and its relevance during the peak winter months of January and December over IGP of India. In order to examine the temporal variability, time series and trend analysis were carried out by using the Mann-Kendall Statistical test. Trend analysis performed by using the Mann-Kendall test, accepts the alternate hypothesis with 95% confidence level indicating that there exists a trend. Kendall tau’s statistics showed that there exists a positive correlation between time series and fog frequency. Further, the Theil and Sen’s median slope estimate showed that the magnitude of trend is positive. Magnitude is higher during January compared to December for the entire IGP except in December when it is high over the western IGP. Decade wise time series analysis revealed that there has been continuous increase in fog days. The net overall increase of 99 % was observed over IGP in last four decades. Diurnal variability and average daily persistence were computed by using descriptive statistical techniques. Geo-statistical analysis of fog was carried out to understand the spatial variability of fog. Geo-statistical analysis of fog revealed that IGP is a high fog prone zone with fog occurrence frequency of more than 66% days during the study period. Diurnal variability indicates the peak occurrence of fog is between 06:00 and 10:00 local time and average daily fog persistence extends to 5 to 7 hours during the peak winter season. The results would offer a new perspective to take proactive measures in reducing the irreparable damage that could be caused due to changing trends of fog.

Keywords: fog, climatology, Mann-Kendall test, trend analysis, spatial variability, temporal variability, visibility

Procedia PDF Downloads 231

Authors: Evrim Colak, Andriy E. Serebryannikov, Thore Magath, Ekmel Ozbay

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Single beam deflection and unidirectional transmission are examined for oblique incidence in a Photonic Crystal (PC) structure which employs defect layer instead of surface corrugations at the interfaces. In all of the studied cases, the defect layer is placed such that the symmetry is broken. Two types of deflection are observed depending on whether the zeroth order is coupled or not. These two scenarios can be distinguished from each other by considering the simulated field distribution in PC. In the first deflection type, Floquet-Bloch mode enables zeroth order coupling. The energy of the zeroth order is redistributed between the diffraction orders at the defect layer, providing deflection. In the second type, when zeroth order is not coupled, strong diffractions cause blazing and the evanescent waves deliver energy to higher order diffraction modes. Simulated isofrequency contours can be utilized to estimate the coupling behavior. The defect layer is placed at varying rows, preserving the asymmetry of PC while evancescent waves can still couple to higher order modes. Even for deeply buried defect layer, asymmetric transmission and beam deflection are still encountered when the zeroth order is not coupled. We assume ε=11.4 (refractive index close to that of GaAs and Si) for the PC rods. A possible operation wavelength can be within microwave and infrared range. Since the suggested material is low loss, the structure can be scaled down to operate higher frequencies. Thus, a sample operation wavelength is selected as 1.5μm. Although the structure employs no surface corrugations transmission value T≈0.97 can be achieved by means of diffraction order m=-1. Moreover, utilizing an extra line defect, T value can be increased upto 0.99, under oblique incidence even if the line defect layer is deeply embedded in the photonic crystal. The latter configuration can be used to obtain deflection in one frequency range and can also be utilized for the realization of another functionality like defect-mode wave guiding in another frequency range but still using the same structure.

Keywords: asymmetric transmission, beam deflection, blazing, bi-directional splitting, defect layer, dual beam splitting, Floquet-Bloch modes, isofrequency contours, line defect, oblique incidence, photonic crystal, unidirectionality

Procedia PDF Downloads 251

Authors: Henok Hailemariam, Frank Wuttke

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Collapsible soils are weak soils that appear to be stable in their natural state, normally dry condition, but rapidly deform under saturation (wetting), thus generating large and unexpected settlements which often yield disastrous consequences for structures unwittingly built on such deposits. In this study, a prediction model for the relative subsidence of stressed collapsible soils based on dielectric permittivity measurement is presented. Unlike most existing methods for soil subsidence prediction, this model does not require moisture content as an input parameter, thus providing the opportunity to obtain accurate estimation of the relative subsidence of collapsible soils using dielectric measurement only. The prediction model is developed based on an existing relative subsidence prediction model (which is dependent on soil moisture condition) and an advanced theoretical frequency and temperature-dependent electromagnetic mixing equation (which effectively removes the moisture content dependence of the original relative subsidence prediction model). For large scale sub-surface soil exploration purposes, the spatial sub-surface soil dielectric data over wide areas and high depths of weak (collapsible) soil deposits can be obtained using non-destructive high frequency electromagnetic (HF-EM) measurement techniques such as ground penetrating radar (GPR). For laboratory or small scale in-situ measurements, techniques such as an open-ended coaxial line with widely applicable time domain reflectometry (TDR) or vector network analysers (VNAs) are usually employed to obtain the soil dielectric data. By using soil dielectric data obtained from small or large scale non-destructive HF-EM investigations, the new model can effectively predict the relative subsidence of weak soils without the need to extract samples for moisture content measurement. Some of the resulting benefits are the preservation of the undisturbed nature of the soil as well as a reduction in the investigation costs and analysis time in the identification of weak (problematic) soils. The accuracy of prediction of the presented model is assessed by conducting relative subsidence tests on a collapsible soil at various initial soil conditions and a good match between the model prediction and experimental results is obtained.

Keywords: collapsible soil, dielectric permittivity, moisture content, relative subsidence

Procedia PDF Downloads 348

Authors: B. Moueddene, B. Labbaci, L. Missoum, R. Abdeldjebar

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Quality estimation of the experimental simulation of boundary conditions is one of the problems encountered while performing an experimental program. In fact, it is not easy to estimate directly the effective influence of these simulations on the results of experimental investigation. The aim of this is article to evaluate the effect of boundary conditions uncertainties on structure response, using the change of the dynamics characteristics. The experimental models used and the correlation by the Frequency Domain Assurance Criterion (FDAC) allowed an interpretation of the change in the dynamic characteristics. The application of this strategy to stratified composite structures (glass/ polyester) has given satisfactory results.

Keywords: vibration, composite, endommagement, correlation

Procedia PDF Downloads 358

Authors: A. Brouri, F. Giri, A. Mkhida, A. Elkarkri, M. L. Chhibat

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Standard Hammerstein-Wiener models consist of a linear subsystem sandwiched by two memoryless nonlinearities. Presently, the linear subsystem is allowed to be parametric or not, continuous- or discrete-time. The input and output nonlinearities are polynomial and may be noninvertible. A two-stage identification method is developed such the parameters of all nonlinear elements are estimated first using the Kozen-Landau polynomial decomposition algorithm. The obtained estimates are then based upon in the identification of the linear subsystem, making use of suitable pre-ad post-compensators.

Keywords: nonlinear system identification, Hammerstein-Wiener systems, frequency identification, polynomial decomposition

Procedia PDF Downloads 497

Authors: Binod C. Agrawal

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In modern history, industrial and media merchandising in South Asia from East Asia, Europe, United States and other countries of the West is over 200 years old. Hence, continued external technology and media exposure is not a new experience in multi-lingual and multi religious South Asia which evolved cultural means to withstand structural change. In the post-World War II phase, media exposure especially of telecommunication, film, Internet, radio, print media and television have increased manifold. South Asia did not lose any time in acquiring and adopting digital media accelerated by chip revolution, computer and satellite communication. The penetration of digital media and utilization are exceptionally high though the spread has an unequal intensity, use and effects. The author argues that industrial and media products are “cultural products” apart from being “technological products”; hence their influences are most felt in the cultural domain which may lead to blunting of unique cultural specifics in the multi-cultural, multi-lingual and multi religious South Asia. Social scientists, political leaders and parents have voiced concern of “Cultural domination”, “Digital media colonization” and “Westernization”. Increased digital media access has also opened up doors of pornography and other harmful information that have sparked fresh debates and discussions about serious negative, harmful, and undesirable social effects especially among youth. Within ‘techno-social’ perspective, based on recent research studies, the paper aims to describe and analyse possible socio-economic change due to digital media penetration. Further, analysis supports the view that the ancient multi-lingual and multi-religious cultures of South Asia due to inner cultural strength may sustain without setting in a process of irreversible structural changes in South Asia.

Keywords: cultural sustainability, digital media effects, digital media impact in South Asia, social change in South Asia

Procedia PDF Downloads 341

Authors: Metuku Shyamsunder, Kakarla Subbarao, P. Prasanna

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In radars, an electromagnetic waveform is sent, and an echo of the same signal is received by the receiver. From this received signal, by extracting various parameters such as round trip delay, Doppler frequency it is possible to find distance, speed, altitude, etc. However, nowadays as the technology increases, intruders are intercepting transmitted signal as it reaches them, and they will be extracting the characteristics and trying to modify them. So there is a need to develop a system whose signal cannot be identified by no cooperative intercept receivers. That is why LPI radars came into existence. In this paper, a brief discussion on LPI radar and its modulation (polytime code (PT1)), detection (cyclostationary (DFSM & FAM) techniques such as DFSM, FAM are presented and compared with respect to computational complexity.

Keywords: LPI radar, polytime codes, cyclostationary DFSM, FAM

Procedia PDF Downloads 464