Search results for: model of postural system behavior
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 33779

Search results for: model of postural system behavior

12569 Reduction of Nitrogen Monoxide with Carbon Monoxide from Gas Streams by 10% wt. Cu-Ce-Fe-Co/Activated Carbon

Authors: K. L. Pan, M. B. Chang

Abstract:

Nitrogen oxides (NOₓ) is regarded as one of the most important air pollutants. It not only causes adverse environmental effects but also harms human lungs and respiratory system. As a post-combustion treatment, selective catalytic reduction (SCR) possess the highest NO removal efficiency ( ≥ 85%), which is considered as the most effective technique for removing NO from gas streams. However, injection of reducing agent such as NH₃ is requested, and it is costly and may cause secondary pollution. Reduction of NO with carbon monoxide (CO) as reducing agent has been previously investigated. In this process, the key step involves the NO adsorption and dissociation. Also, the high performance mainly relies on the amounts of oxygen vacancy on catalyst surface and redox ability of catalyst, because oxygen vacancy can activate the N-O bond to promote its dissociation. Additionally, perfect redox ability can promote the adsorption of NO and oxidation of CO. Typically, noble metals such as iridium (Ir), platinum (Pt), and palladium (Pd) are used as catalyst for the reduction of NO with CO; however, high cost has limited their applications. Recently, transition metal oxides have been investigated for the reduction of NO with CO, especially CuₓOy, CoₓOy, Fe₂O₃, and MnOₓ are considered as effective catalysts. However, deactivation is inevitable as oxygen (O₂) exists in the gas streams because active sites (oxygen vacancies) of catalyst are occupied by O₂. In this study, Cu-Ce-Fe-Co is prepared and supported on activated carbon by impregnation method to form 10% wt. Cu-Ce-Fe-Co/activated carbon catalyst. Generally, addition of activated carbon on catalyst can bring several advantages: (1) NO can be effectively adsorbed by interaction between catalyst and activated carbon, resulting in the improvement of NO removal, (2) direct NO decomposition may be achieved over carbon associated with catalyst, and (3) reduction of NO could be enhanced by a reducing agent over carbon-supported catalyst. Therefore, 10% wt. Cu-Ce-Fe-Co/activated carbon may have better performance for reduction of NO with CO. Experimental results indicate that NO conversion achieved with 10% wt. Cu-Ce-Fe-Co/activated carbon reaches 83% at 150°C with 300 ppm NO and 10,000 ppm CO. As temperature is further increased to 200°C, 100% NO conversion could be achieved, implying that 10% wt. Cu-Ce-Fe-Co/activated carbon prepared has good activity for the reduction of NO with CO. In order to investigate the effect of O₂ on reduction of NO with CO, 1-5% O₂ are introduced into the system. The results indicate that NO conversions still maintain at ≥ 90% with 1-5% O₂ conditions at 200°C. It is worth noting that effect of O₂ on reduction of NO with CO could be significantly improved as carbon is used as support. It is inferred that carbon support can react with O₂ to produce CO₂ as O₂ exists in the gas streams. Overall, 10% wt. Cu-Ce-Fe-Co/activated carbon is demonstrated with good potential for reduction of NO with CO, and possible mechanisms will be elucidated in this paper.

Keywords: nitrogen oxides (NOₓ), carbon monoxide (CO), reduction of NO with CO, carbon material, catalysis

Procedia PDF Downloads 256
12568 Educational Related Information Technology Department Transformation: A Case Study

Authors: P. Joongsiri, K. Pattanapisuth, P. Siwatintuko, S. Vasupongayya

Abstract:

This paper presents a case study of developing a four-year plan for the information technology department at the Faculty of Engineering, Prince of Songkla University, Thailand. This work can be used as a case study for other in-house information technology department in a higher educational environment. The result of this paper is the guideline of the four year plan creation process which is generated by analyzing the related theories and several best practices.

Keywords: strategic plan, management information system, information technology department governance, best practices, organization transformation

Procedia PDF Downloads 458
12567 Development of a Fire Analysis Drone for Smoke Toxicity Measurement for Fire Prediction and Management

Authors: Gabrielle Peck, Ryan Hayes

Abstract:

This research presents the design and creation of a drone gas analyser, aimed at addressing the need for independent data collection and analysis of gas emissions during large-scale fires, particularly wasteland fires. The analyser drone, comprising a lightweight gas analysis system attached to a remote-controlled drone, enables the real-time assessment of smoke toxicity and the monitoring of gases released into the atmosphere during such incidents. The key components of the analyser unit included two gas line inlets connected to glass wool filters, a pump with regulated flow controlled by a mass flow controller, and electrochemical cells for detecting nitrogen oxides, hydrogen cyanide, and oxygen levels. Additionally, a non-dispersive infrared (NDIR) analyser is employed to monitor carbon monoxide (CO), carbon dioxide (CO₂), and hydrocarbon concentrations. Thermocouples can be attached to the analyser to monitor temperature, as well as McCaffrey probes combined with pressure transducers to monitor air velocity and wind direction. These additions allow for monitoring of the large fire and can be used for predictions of fire spread. The innovative system not only provides crucial data for assessing smoke toxicity but also contributes to fire prediction and management. The remote-controlled drone's mobility allows for safe and efficient data collection in proximity to the fire source, reducing the need for human exposure to hazardous conditions. The data obtained from the gas analyser unit facilitates informed decision-making by emergency responders, aiding in the protection of both human health and the environment. This abstract highlights the successful development of a drone gas analyser, illustrating its potential for enhancing smoke toxicity analysis and fire prediction capabilities. The integration of this technology into fire management strategies offers a promising solution for addressing the challenges associated with wildfires and other large-scale fire incidents. The project's methodology and results contribute to the growing body of knowledge in the field of environmental monitoring and safety, emphasizing the practical utility of drones for critical applications.

Keywords: fire prediction, drone, smoke toxicity, analyser, fire management

Procedia PDF Downloads 89
12566 Characteristics Influencing Response of a Base Isolated Building

Authors: Ounis Hadj Mohamed, Ounis Abdelhafid

Abstract:

In order to illustrate the effect of damping on the response of a base-isolated building, a parametric study is led, taking into account the progressive variation of the damping ratio (10% to 30%) under different types of seismic excitations (near and far field). A time history analysis is used to determine the response of the structure in terms of relative displacement and understory drift at various levels of the building. Thus, the results show that the efficiency of the isolator increases with the assumed damping ratio, provided that this latter is less or equal to 20%. Beyond this value, the isolator becomes less convenient. Furthermore, a strong deviation of energy capacity by the LRB (Lead Rubber Bearing) system is recorded.

Keywords: damping, base isolation, LRB, seismic excitation, hysteresis

Procedia PDF Downloads 416
12565 Evaluation of Reservoir Quality in Cretaceous Sandstone Complex, Western Flank of Anambra Basin, Southern Nigeria

Authors: Bayole Omoniyi

Abstract:

This study demonstrates the value of outcrops as analogues for evaluating reservoir quality of sandbody in a typical high-sinuosity fluvial system. The study utilized data acquired from selected outcrops in the Campanian-Maastrichtian siliciclastic succession of the western flank of Anambra Basin, southern Nigeria. Textural properties derived from outcrop samples were correlated and compared with porosity and permeability using established standard charts. Porosity was estimated from thin sections of selected samples to reduce uncertainty in the estimates. Following facies classification, 14 distinct facies were grouped into three facies associations (FA1-FA3) and were subsequently modeled as discrete properties in a block-centered Cartesian grid on a scale that captures geometry of principal sandbodies. Porosity and permeability estimated from charts were populated in the grid using comparable geostatistical techniques that reflect their spatial distribution. The resultant models were conditioned to facies property to honour available data. The results indicate a strong control of geometrical parameters on facies distribution, lateral continuity and connectivity with resultant effect on porosity and permeability distribution. Sand-prone FA1 and FA2 display reservoir quality that varies internally from channel axis to margin in each succession. Furthermore, isolated stack pattern of sandbodies reduces static connectivity and thus, increases risk of poor communication between reservoir-quality sandbodies. FA3 is non-reservoir because it is mud-prone. In conclusion, the risk of poor communication between sandbodies may be effectively accentuated in reservoirs that have similar architecture because of thick lateral accretion deposits, usually mudstone, that tend to disconnect good-quality point-bar sandbodies. In such reservoirs, mudstone may act as a barrier to impede flow vertically from one sandbody to another and laterally at the margins of each channel-fill succession in the system. The development plan, therefore, must be designed to effectively mitigate these risks and the risk of stratigraphic compartmentalization for maximum hydrocarbon recovery.

Keywords: analogues, architecture, connectivity, fluvial

Procedia PDF Downloads 24
12564 PbLi Activation Due to Corrosion Products in WCLL BB (EU-DEMO) and Its Impact on Reactor Design and Recycling

Authors: Nicole Virgili, Marco Utili

Abstract:

The design of the Breeding Blanket in Tokamak fusion energy systems has to guarantee sufficient availability in addition to its functions, that are, tritium breeding self-sufficiency, power extraction and shielding (the magnets and the VV). All these function in the presence of extremely harsh operating conditions in terms of heat flux and neutron dose as well as chemical environment of the coolant and breeder that challenge structural materials (structural resistance and corrosion resistance). The movement and activation of fluids from the BB to the Ex-vessel components in a fusion power plant have an important radiological consideration because flowing material can carry radioactivity to safety-critical areas. This includes gamma-ray emission from activated fluid and activated corrosion products, and secondary activation resulting from neutron emission, with implication for the safety of maintenance personnel and damage to electrical and electronic equipment. In addition to the PbLi breeder activation, it is important to evaluate the contribution due to the activated corrosion products (ACPs) dissolved in the lead-lithium eutectic alloy, at different concentration levels. Therefore, the purpose of the study project is to evaluate the PbLi activity utilizing the FISPACT II inventory code. Emphasis is given on how the design of the EU-DEMO WCLL, and potential recycling of the breeder material will be impacted by the activation of PbLi and the associated active corrosion products (ACPs). For this scope the following Computational Tools, Data and Geometry have been considered: • Neutron source: EU-DEMO neutron flux < 1014/cm2/s • Neutron flux distribution in equatorial breeding blanket module (BBM) #13 in the WCLL BB outboard central zone, which is the most activated zone, with the aim to introduce a conservative component utilizing MNCP6. • The recommended geometry model: 2017 EU DEMO CAD model. • Blanket Module Material Specifications (Composition) • Activation calculations for different ACP concentration levels in the PbLi breeder, with a given chemistry in stationary equilibrium conditions, using FISPACT II code. Results suggest that there should be a waiting time of about 10 years from the shut-down (SD) to be able to safely manipulate the PbLi for recycling operations with simple shielding requirements. The dose rate is mainly given by the PbLi and the ACP concentration (x1 or x 100) does not shift the result. In conclusion, the results show that there is no impact on PbLi activation due to ACPs levels.

Keywords: activation, corrosion products, recycling, WCLL BB., PbLi

Procedia PDF Downloads 131
12563 Bioreactor for Cell-Based Impedance Measuring with Diamond Coated Gold Interdigitated Electrodes

Authors: Roman Matejka, Vaclav Prochazka, Tibor Izak, Jana Stepanovska, Martina Travnickova, Alexander Kromka

Abstract:

Cell-based impedance spectroscopy is suitable method for electrical monitoring of cell activity especially on substrates that cannot be easily inspected by optical microscope (without fluorescent markers) like decellularized tissues, nano-fibrous scaffold etc. Special sensor for this measurement was developed. This sensor consists of corning glass substrate with gold interdigitated electrodes covered with diamond layer. This diamond layer provides biocompatible non-conductive surface for cells. Also, a special PPFC flow cultivation chamber was developed. This chamber is able to fix sensor in place. The spring contacts are connecting sensor pads with external measuring device. Construction allows real-time live cell imaging. Combining with perfusion system allows medium circulation and generating shear stress stimulation. Experimental evaluation consist of several setups, including pure sensor without any coating and also collagen and fibrin coating was done. The Adipose derived stem cells (ASC) and Human umbilical vein endothelial cells (HUVEC) were seeded onto sensor in cultivation chamber. Then the chamber was installed into microscope system for live-cell imaging. The impedance measurement was utilized by vector impedance analyzer. The measured range was from 10 Hz to 40 kHz. These impedance measurements were correlated with live-cell microscopic imaging and immunofluorescent staining. Data analysis of measured signals showed response to cell adhesion of substrates, their proliferation and also change after shear stress stimulation which are important parameters during cultivation. Further experiments plan to use decellularized tissue as scaffold fixed on sensor. This kind of impedance sensor can provide feedback about cell culture conditions on opaque surfaces and scaffolds that can be used in tissue engineering in development artificial prostheses. This work was supported by the Ministry of Health, grants No. 15-29153A and 15-33018A.

Keywords: bio-impedance measuring, bioreactor, cell cultivation, diamond layer, gold interdigitated electrodes, tissue engineering

Procedia PDF Downloads 301
12562 Acceptance of Big Data Technologies and Its Influence towards Employee’s Perception on Job Performance

Authors: Jia Yi Yap, Angela S. H. Lee

Abstract:

With the use of big data technologies, organization can get result that they are interested in. Big data technologies simply load all the data that is useful for the organizations and provide organizations a better way of analysing data. The purpose of this research is to get employees’ opinion from films in Malaysia to explore the use of big data technologies in their organization in order to provide how it may affect the perception of the employees on job performance. Therefore, in order to identify will accepting big data technologies in the organization affect the perception of the employee, questionnaire will be distributed to different employee from different Small and medium-sized enterprises (SME) organization listed in Malaysia. The conceptual model proposed will test with other variables in order to see the relationship between variables.

Keywords: big data technologies, employee, job performance, questionnaire

Procedia PDF Downloads 298
12561 Deep Neck Infection Associated with Peritoneal Sepsis: A Rare Death Case

Authors: Sait Ozsoy, Asude Gokmen, Mehtap Yondem, Hanife A. Alkan, Gulnaz T. Javan

Abstract:

Deep neck infection often develops due to upper respiratory tract and odontogenic infections. Gastrointestinal System perforation can occur for many reasons and is in need of the early diagnosis and prompt surgical treatment. In both cases late or incorrect diagnosis may lead to increase morbidity and high mortality. A patient with a diagnosis of deep neck abscess died while under treatment due to sepsis and multiple organ failure. Autopsy finding showed duodenal ulcer and this is reported in the literature.

Keywords: peptic ulcer perforation, peritonitis, retropharyngeal abscess, sepsis

Procedia PDF Downloads 498
12560 Cyclostationary Analysis of Polytime Coded Signals for LPI Radars

Authors: Metuku Shyamsunder, Kakarla Subbarao, P. Prasanna

Abstract:

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 476
12559 Sensing Endocrine Disrupting Chemicals by Virus-Based Structural Colour Nanostructure

Authors: Lee Yujin, Han Jiye, Oh Jin-Woo

Abstract:

The adverse effects of endocrine disrupting chemicals (EDCs) has attracted considerable public interests. The benzene-like EDCs structure mimics the mechanisms of hormones naturally occurring in vivo, and alters physiological function of the endocrine system. Although, some of the most representative EDCs such as polychlorinated biphenyls (PCBs) and phthalates compounds already have been prohibited to produce and use in many countries, however, PCBs and phthalates in plastic products as flame retardant and plasticizer are still circulated nowadays. EDCs can be released from products while using and discarding, and it causes serious environmental and health issues. Here, we developed virus-based structurally coloured nanostructure that can detect minute EDCs concentration sensitively and selectively. These structurally coloured nanostructure exhibits characteristic angel-independent colors due to the regular virus bundle structure formation through simple pulling technique. The designed number of different colour bands can be formed through controlling concentration of virus solution and pulling speed. The virus, M-13 bacteriophage, was genetically engineered to react with specific ECDs, typically PCBs and phthalates. M-13 bacteriophage surface (pVIII major coat protein) was decorated with benzene derivative binding peptides (WHW) through phage library method. In the initial assessment, virus-based color sensor was exposed to several organic chemicals including benzene, toluene, phenol, chlorobenzene, and phthalic anhydride. Along with the selectivity evaluation of virus-based colour sensor, it also been tested for sensitivity. 10 to 300 ppm of phthalic anhydride and chlorobenzene were detected by colour sensor, and showed the significant sensitivity with about 90 of dissociation constant. Noteworthy, all measurements were analyzed through principal component analysis (PCA) and linear discrimination analysis (LDA), and exhibited clear discrimination ability upon exposure to 2 categories of EDCs (PCBs and phthalates). Because of its easy fabrication, high sensitivity, and the superior selectivity, M-13 bacteriophage-based color sensor could be a simple and reliable portable sensing system for environmental monitoring, healthcare, social security, and so on.

Keywords: M-13 bacteriophage, colour sensor, genetic engineering, EDCs

Procedia PDF Downloads 242
12558 Verification Protocols for the Lightning Protection of a Large Scale Scientific Instrument in Harsh Environments: A Case Study

Authors: Clara Oliver, Oibar Martinez, Jose Miguel Miranda

Abstract:

This paper is devoted to the study of the most suitable protocols to verify the lightning protection and ground resistance quality in a large-scale scientific facility located in a harsh environment. We illustrate this work by reviewing a case study: the largest telescopes of the Northern Hemisphere Cherenkov Telescope Array, CTA-N. This array hosts sensitive and high-speed optoelectronics instrumentation and sits on a clear, free from obstacle terrain at around 2400 m above sea level. The site offers a top-quality sky but also features challenging conditions for a lightning protection system: the terrain is volcanic and has resistivities well above 1 kOhm·m. In addition, the environment often exhibits humidities well below 5%. On the other hand, the high complexity of a Cherenkov telescope structure does not allow a straightforward application of lightning protection standards. CTA-N has been conceived as an array of fourteen Cherenkov Telescopes of two different sizes, which will be constructed in La Palma Island, Spain. Cherenkov Telescopes can provide valuable information on different astrophysical sources from the gamma rays reaching the Earth’s atmosphere. The largest telescopes of CTA are called LST’s, and the construction of the first one was finished in October 2018. The LST has a shape which resembles a large parabolic antenna, with a 23-meter reflective surface supported by a tubular structure made of carbon fibers and steel tubes. The reflective surface has 400 square meters and is made of an array of segmented mirrors that can be controlled individually by a subsystem of actuators. This surface collects and focuses the Cherenkov photons into the camera, where 1855 photo-sensors convert the light in electrical signals that can be processed by dedicated electronics. We describe here how the risk assessment of direct strike impacts was made and how down conductors and ground system were both tested. The verification protocols which should be applied for the commissioning and operation phases are then explained. We stress our attention on the ground resistance quality assessment.

Keywords: grounding, large scale scientific instrument, lightning risk assessment, lightning standards and safety

Procedia PDF Downloads 123
12557 The Predictors of Student Engagement: Instructional Support vs Emotional Support

Authors: Tahani Salman Alangari

Abstract:

Student success can be impacted by internal factors such as their emotional well-being and external factors such as organizational support and instructional support in the classroom. This study is to identify at least one factor that forecasts student engagement. It is a cross-sectional, conducted on 6206 teachers and encompassed three years of data collection and observations of math instruction in approximately 50 schools and 300 classrooms. A multiple linear regression revealed that a model predicting student engagement from emotional support, classroom organization, and instructional support was significant. Four linear regression models were tested using hierarchical regression to examine the effects of independent variables: emotional support was the highest predictor of student engagement while instructional support was the lowest.

Keywords: student engagement, emotional support, organizational support, instructional support, well-being

Procedia PDF Downloads 81
12556 Cellular Traffic Prediction through Multi-Layer Hybrid Network

Authors: Supriya H. S., Chandrakala B. M.

Abstract:

Deep learning based models have been recently successful adoption for network traffic prediction. However, training a deep learning model for various prediction tasks is considered one of the critical tasks due to various reasons. This research work develops Multi-Layer Hybrid Network (MLHN) for network traffic prediction and analysis; MLHN comprises the three distinctive networks for handling the different inputs for custom feature extraction. Furthermore, an optimized and efficient parameter-tuning algorithm is introduced to enhance parameter learning. MLHN is evaluated considering the “Big Data Challenge” dataset considering the Mean Absolute Error, Root Mean Square Error and R^2as metrics; furthermore, MLHN efficiency is proved through comparison with a state-of-art approach.

Keywords: MLHN, network traffic prediction

Procedia PDF Downloads 89
12555 Association between Dental Caries and Asthma among 12-15 Years Old School Children Studying in Karachi, Pakistan: A Cross Sectional Study

Authors: Wajeeha Zahid, Shafquat Rozi, Farhan Raza, Masood Kadir

Abstract:

Background: Dental caries affects the overall health and well-being of children. Findings from various international studies regarding the association of dental caries with asthma are inconsistent. With the increasing burden of caries and childhood asthma, it becomes imperative for an underdeveloped country like Pakistan where resources are limited to identify whether there is a relationship between the two. This study aims to identify an association between dental caries and asthma. Methods: A cross-sectional study was conducted on 544 children aged 12-15 years recruited from five private schools in Karachi. Information on asthma was collected through the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. The questionnaire addressed questions regarding child’s demographics, physician diagnoses of asthma, type of medication administered, family history of asthma and allergies, dietary habits and oral hygiene behavior. Dental caries was assessed using DMFT Index (Decayed, Missing, Filled teeth) index The data was analyzed using Cox proportional Hazard algorithm and crude and adjusted prevalence ratios with 95% CI were reported. Results: This study comprises of 306 (56.3%) boys and 238 (43.8%) girls. The mean age of children was 13.2 ± (0.05) years. The total number of children with carious teeth (DMFT > 0) were 166/544 (30.5%), and the decayed component contributed largely (22.8%) to the DMFT score. The prevalence of physician’s diagnosed asthma was 13%. This study identified almost 7% asthmatic children using the internationally validated International Study of Asthma and Allergies in Childhood (ISAAC) tool and 8 children with childhood asthma were identified by parent interviews. Overall prevalence of asthma was 109/544 (20%). The prevalence of caries in asthmatic children was 28.4% as compared to 31% among non-asthmatic children. The adjusted prevalence ratio of dental caries in asthmatic children was 0.8 (95% CI 0.59-1.29). After adjusting for carious food intake, age, oral hygiene index and dentist visit, the association between asthma and dental caries turned out to be non-significant. Conclusion: There was no association between asthma and dental caries among children who participated in this study.

Keywords: asthma, caries, children, school-based

Procedia PDF Downloads 246
12554 Integrating One Health Approach with National Policies to Improve Health Security post-COVID-19 in Vietnam

Authors: Yasser Sanad, Thu Trang Dao

Abstract:

Introduction: Implementing the One Health (OH) approach requires an integrated, interdisciplinary, and cross-sectoral methodology. OH is a key tool for developing and implementing programs and projects and includes developing ambitious policies that consider the common needs and benefits of human, animal, plant, and ecosystem health. OH helps humanity readjust its path to environmentally friendly and impartial sustainability. As co-leader of the Global Health Security Agenda’s Zoonotic Disease Action Package, Vietnam pioneered a strong OH approach to effectively address early waves of the COVID-19 outbreak in-country. Context and Aim: The repeated surges in COVID-19 in Vietnam challenged the capabilities of the national system and disclosed the gaps in multi-sectoral coordination and resilience. To address this, FHI 360 advocated for the standardization of the OH platform by government actors to increase the resiliency of the system during and post COVID-19. Methods: FHI 360 coordinated technical resources to develop and implement evidence-based OH policies, promoting high-level policy dialogue between the Ministries of Health, Agriculture, and the Environment, and policy research to inform developed policies and frameworks. Through discussions, an OH-building Partnership (OHP) was formed, linking climate change, the environment, and human and animal health. Findings: The OHP Framework created a favorable policy environment within and between sectors, as well as between governments and international health security partners. It also promoted strategic dialogue, resource mobilization, policy advocacy, and integration of international systems with National Steering Committees to ensure accountability and emphasize national ownership. Innovative contribution to policy, practice and/or research: OHP was an effective evidence-based research-to-policy platform linking to the National One Health Strategic Plan (2021-2025). Collectively they serve as a national framework for the implementation and monitoring of OH activities. Through the adoption of policies and plans, the risk of zoonotic pathogens, environmental agent spillover, and antimicrobial resistance can be minimized through strengthening multi-sectoral OH collaboration for health security.

Keywords: one health, national policies, health security, COVID-19, Vietnam

Procedia PDF Downloads 105
12553 Auditory Perception of Frequency-Modulated Sweeps and Reading Difficulties in Chinese

Authors: Hsiao-Lan Wang, Chun-Han Chiang, I-Chen Chen

Abstract:

In Chinese Mandarin, lexical tones play an important role to provide contrasts in word meaning. They are pitch patterns and can be quantified as the fundamental frequency (F0), expressed in Hertz (Hz). In this study, we aim to investigate the influence of frequency discrimination on Chinese children’s performance of reading abilities. Fifty participants from 3rd to 4th grades, including 24 children with reading difficulties and 26 age-matched children, were examined. A serial of cognitive, language, reading and psychoacoustic tests were administrated. Magnetoencephalography (MEG) was also employed to study children’s auditory sensitivity. In the present study, auditory frequency was measured through slide-up pitch, slide-down pitch and frequency-modulated tone. The results showed that children with Chinese reading difficulties were significantly poor at phonological awareness and auditory discrimination for the identification of frequency-modulated tone. Chinese children’s character reading performance was significantly related to lexical tone awareness and auditory perception of frequency-modulated tone. In our MEG measure, we compared the mismatch negativity (MMNm), from 100 to 200 ms, in two groups. There were no significant differences between groups during the perceptual discrimination of standard sounds, fast-up and fast-down frequencies. However, the data revealed significant cluster differences between groups in the slow-up and slow-down frequencies discrimination. In the slow-up stimulus, the cluster demonstrated an upward field map at 106-151 ms (p < .001) with a strong peak time at 127ms. The source analyses of two dipole model and localization resolution model (CLARA) from 100 to 200 ms both indicated a strong source from the left temporal area with 45.845% residual variance. Similar results were found in the slow-down stimulus with a larger upward current at 110-142 ms (p < 0.05) and a peak time at 117 ms in the left temporal area (47.857% residual variance). In short, we found a significant group difference in the MMNm while children processed frequency-modulated tones with slow temporal changes. The findings may imply that perception of sound frequency signals with slower temporal modulations was related to reading and language development in Chinese. Our study may also support the recent hypothesis of underlying non-verbal auditory temporal deficits accounting for the difficulties in literacy development seen developmental dyslexia.

Keywords: Chinese Mandarin, frequency modulation sweeps, magnetoencephalography, mismatch negativity, reading difficulties

Procedia PDF Downloads 576
12552 User-Controlled Color-Changing Textiles: From Prototype to Mass Production

Authors: Joshua Kaufman, Felix Tan, Morgan Monroe, Ayman Abouraddy

Abstract:

Textiles and clothing have been a staple of human existence for millennia, yet the basic structure and functionality of textile fibers and yarns has remained unchanged. While color and appearance are essential characteristics of a textile, an advancement in the fabrication of yarns that allows for user-controlled dynamic changes to the color or appearance of a garment has been lacking. Touch-activated and photosensitive pigments have been used in textiles, but these technologies are passive and cannot be controlled by the user. The technology described here allows the owner to control both when and in what pattern the fabric color-change takes place. In addition, the manufacturing process is compatible with mass-producing the user-controlled, color-changing yarns. The yarn fabrication utilizes a fiber spinning system that can produce either monofilament or multifilament yarns. For products requiring a more robust fabric (backpacks, purses, upholstery, etc.), larger-diameter monofilament yarns with a coarser weave are suitable. Such yarns are produced using a thread-coater attachment to encapsulate a 38-40 AWG metal wire inside a polymer sheath impregnated with thermochromic pigment. Conversely, products such as shirts and pants requiring yarns that are more flexible and soft against the skin comprise multifilament yarns of much smaller-diameter individual fibers. Embedding a metal wire in a multifilament fiber spinning process has not been realized to date. This research has required collaboration with Hills, Inc., to design a liquid metal-injection system to be combined with fiber spinning. The new system injects molten tin into each of 19 filaments being spun simultaneously into a single yarn. The resulting yarn contains 19 filaments, each with a tin core surrounded by a polymer sheath impregnated with thermochromic pigment. The color change we demonstrate is distinct from garments containing LEDs that emit light in various colors. The pigment itself changes its optical absorption spectrum to appear a different color. The thermochromic color-change is induced by a temperature change in the inner metal wire within each filament when current is applied from a small battery pack. The temperature necessary to induce the color change is near body temperature and not noticeable by touch. The prototypes already developed either use a simple push button to activate the battery pack or are wirelessly activated via a smart-phone app over Wi-Fi. The app allows the user to choose from different activation patterns of stripes that appear in the fabric continuously. The power requirements are mitigated by a large hysteresis in the activation temperature of the pigment and the temperature at which there is full color return. This was made possible by a collaboration with Chameleon International to develop a new, customized pigment. This technology enables a never-before seen capability: user-controlled, dynamic color and pattern change in large-area woven and sewn textiles and fabrics with wide-ranging applications from clothing and accessories to furniture and fixed-installation housing and business décor. The ability to activate through Wi-Fi opens up possibilities for the textiles to be part of the ‘Internet of Things.’ Furthermore, this technology is scalable to mass-production levels for wide-scale market adoption.

Keywords: activation, appearance, color, manufacturing

Procedia PDF Downloads 278
12551 Regulatory Governance as a De-Parliamentarization Process: A Contextual Approach to Global Constitutionalism and Its Effects on New Arab Legislatures

Authors: Abderrahim El Maslouhi

Abstract:

The paper aims to analyze an often-overlooked dimension of global constitutionalism, which is the rise of the regulatory state and its impact on parliamentary dynamics in transition regimes. In contrast to Majone’s technocratic vision of convergence towards a single regulatory system based on competence and efficiency, national transpositions of regulatory governance and, in general, the relationship to global standards primarily depend upon a number of distinctive parameters. These include policy formation process, speed of change, depth of parliamentary tradition and greater or lesser vulnerability to the normative conditionality of donors, interstate groupings and transnational regulatory bodies. Based on a comparison between three post-Arab Spring countries -Morocco, Tunisia, and Egypt, whose constitutions have undergone substantive review in the period 2011-2014- and some European Union state members, the paper intends, first, to assess the degree of permeability to global constitutionalism in different contexts. A noteworthy divide emerges from this comparison. Whereas European constitutions still seem impervious to the lexicon of global constitutionalism, the influence of the latter is obvious in the recently drafted constitutions in Morocco, Tunisia, and Egypt. This is evidenced by their reference to notions such as ‘governance’, ‘regulators’, ‘accountability’, ‘transparency’, ‘civil society’, and ‘participatory democracy’. Second, the study will provide a contextual account of internal and external rationales underlying the constitutionalization of regulatory governance in the cases examined. Unlike European constitutionalism, where parliamentarism and the tradition of representative government function as a structural mechanism that moderates the de-parliamentarization effect induced by global constitutionalism, Arab constitutional transitions have led to a paradoxical situation; contrary to the public demands for further parliamentarization, the 2011 constitution-makers have opted for a de-parliamentarization pattern. This is particularly reflected in the procedures established by constitutions and regular legislation, to handle the interaction between lawmakers and regulatory bodies. Once the ‘constitutional’ and ‘independent’ nature of these agencies is formally endorsed, the birth of these ‘fourth power’ entities, which are neither elected nor directly responsible to elected officials, will raise the question of their accountability. Third, the paper shows that, even in the three selected countries, the de-parliamentarization intensity is significantly variable. By contrast to the radical stance of the Moroccan and Egyptian constituents who have shown greater concern to shield regulatory bodies from legislatures’ scrutiny, the Tunisian case indicates a certain tendency to provide lawmakers with some essential control instruments (e. g. exclusive appointment power, adversarial discussion of regulators’ annual reports, dismissal power, later held unconstitutional). In sum, the comparison reveals that the transposition of the regulatory state model and, more generally, sensitivity to the legal implications of global conditionality essentially relies on the evolution of real-world power relations at both national and international levels.

Keywords: Arab legislatures, de-parliamentarization, global constitutionalism, normative conditionality, regulatory state

Procedia PDF Downloads 138
12550 Supplier Selection by Considering Cost and Reliability

Authors: K. -H. Yang

Abstract:

Supplier selection problem is one of the important issues of supply chain problems. Two categories of methodologies include qualitative and quantitative approaches which can be applied to supplier selection problems. However, due to the complexities of the problem and lacking of reliable and quantitative data, qualitative approaches are more than quantitative approaches. This study considers operational cost and supplier’s reliability factor and solves the problem by using a quantitative approach. A mixed integer programming model is the primary analytic tool. Analyses of different scenarios with variable cost and reliability structures show that the effectiveness of this approach to the supplier selection problem.

Keywords: mixed integer programming, quantitative approach, supplier’s reliability, supplier selection

Procedia PDF Downloads 384
12549 Investigations on Pyrolysis Model for Radiatively Dominant Diesel Pool Fire Using Fire Dynamic Simulator

Authors: Siva K. Bathina, Sudheer Siddapureddy

Abstract:

Pool fires are formed when the flammable liquid accidentally spills on the ground or water and ignites. Pool fire is a kind of buoyancy-driven and diffusion flame. There have been many pool fire accidents caused during processing, handling and storing of liquid fuels in chemical and oil industries. Such kind of accidents causes enormous damage to property as well as the loss of lives. Pool fires are complex in nature due to the strong interaction among the combustion, heat and mass transfers and pyrolysis at the fuel surface. Moreover, the experimental study of such large complex fires involves fire safety issues and difficulties in performing experiments. In the present work, large eddy simulations are performed to study such complex fire scenarios using fire dynamic simulator. A 1 m diesel pool fire is considered for the studied cases, and diesel is chosen as it is most commonly involved fuel in fire accidents. Fire simulations are performed by specifying two different boundary conditions: one the fuel is in liquid state and pyrolysis model is invoked, and the other by assuming the fuel is initially in a vapor state and thereby prescribing the mass loss rate. A domain of size 11.2 m × 11.2 m × 7.28 m with uniform structured grid is chosen for the numerical simulations. Grid sensitivity analysis is performed, and a non-dimensional grid size of 12 corresponding to 8 cm grid size is considered. Flame properties like mass burning rate, irradiance, and time-averaged axial flame temperature profile are predicted. The predicted steady-state mass burning rate is 40 g/s and is within the uncertainty limits of the previously reported experimental data (39.4 g/s). Though the profile of the irradiance at a distance from the fire along the height is somewhat in line with the experimental data and the location of the maximum value of irradiance is shifted to a higher location. This may be due to the lack of sophisticated models for the species transportation along with combustion and radiation in the continuous zone. Furthermore, the axial temperatures are not predicted well (for any of the boundary conditions) in any of the zones. The present study shows that the existing models are not sufficient enough for modeling blended fuels like diesel. The predictions are strongly dependent on the experimental values of the soot yield. Future experiments are necessary for generalizing the soot yield for different fires.

Keywords: burning rate, fire accidents, fire dynamic simulator, pyrolysis

Procedia PDF Downloads 196
12548 Investigation of the Effects of Sampling Frequency on the THD of 3-Phase Inverters Using Space Vector Modulation

Authors: Khattab Al Qaisi, Nicholas Bowring

Abstract:

This paper presents the simulation results of the effects of sampling frequency on the total harmonic distortion (THD) of three-phase inverters using the space vector pulse width modulation (SVPWM) and space vector control (SVC) algorithms. The relationship between the variables was studied using curve fitting techniques, and it has been shown that, for 50 Hz inverters, there is an exponential relation between the sampling frequency and THD up to around 8500 Hz, beyond which the performance of the model becomes irregular, and there is an negative exponential relation between the sampling frequency and the marginal improvement to the THD. It has also been found that the performance of SVPWM is better than that of SVC with the same sampling frequency in most frequency range, including the range where the performance of the former is irregular.

Keywords: DSI, SVPWM, THD, DC-AC converter, sampling frequency, performance

Procedia PDF Downloads 485
12547 The Impact of Total Dust (LGS) and Mineral Dust (PM 10) in Cardio Vascular and Respiratory System, in Albania: A Longitudinal Study

Authors: Canga Mimoza, Irene Malagnino, Giulia Malagnino, Vito Malagnino

Abstract:

Aim: This study aims at evaluating the impact of total dust (LGS) and mineral dust (PM10), in the cardio vascular and respiratory systems. Also proving that these air polluters are the cause of several diseases, such as bronchopneumonia, pneumonia, bronchitis, angina pectoris and cardiac insufficiency. Material and Method: The study is concentrated in the cities of Fier and Vlora. This is a clinic-epidemiological study conducted during the time period 2014-2019. Some of the data of LGS and PM10 were obtained from the database of the Institute of Public Health. The formula to measure the mean value of LGS and PM10 is ∆X=X (mean)-Xᵢ. Results: Based on the calculations made, we noticed that: The mean value of LGS in the city of Fieri was 227,33, while the mean value of LGS in the city of Vlora was 177,4. Whereas, the mean value of PM10 in the city of Fieri was 105.5 and the mean value of PM10 in the city of Vlore was 77.5. According to, our statistics the values of LGS were 1.2 times higher in Fier than in Vlora and the PM10 values were 1.36 times higher in Fier than in Vlora. Based on the data, in the city of Fier, the incidence of the bronchopneumonia was 56.53 sick patients/1000 inhabitants, but in Vlora, it was 22 sick patients/1000 inhabitants, so the number of the sick patients was 2.5 times higher in the city of Fieri compared with Vlora city, (P=0.001). The number of the patients with bronchitis, in the city of Fier, was 18 patients/1000 inhabitants, whereas, in Vlora, it was 9 patients/1000 inhabitants, (P=0.005). Based on the data, 8 patients/1000 inhabitants in the city of Fier, suffered from the pneumonia disease, while in Vlora city, were 4 patients/1000 inhabitants, (P=0.005). Another disease taken in consideration was angina pectoris. This study can claim that in the city of Fier, 9.5 patients/1000 inhabitants suffered from this disease, while in Vlora city, were only 4 patients /1000 inhabitants, (P=0.001). Findings of the present study proved that 3.7 patients/1000 inhabitants in the city of Fieri, had cardiac insufficiency, whereas in the city of Vlora, were 1.8 patients/1000 inhabitants, (P=0.05). Conclusions: LGS and PM10 have an influential impact on the cardio vascular and respiratory system; that’s why their levels should be kept under control. The pollution levels are 1.2 and 1.4 times higher in Fier than in Vlora; also the incidences of the diseases are 2 times higher in Fier than in Vlora. Recommendations: In order to prevent the cardio vascular and respiratory diseases, we should avoid places where pollution is higher than the norm. This can be achieved by frequenting places where the air pollution is lower, such as parks, gardens, top floors, etc.

Keywords: impact of total dust, LGS, mineral dust, PM 10, cardio vascular pathologies, respiratory disease

Procedia PDF Downloads 128
12546 Analysis of DNA from Fired Cartridge Casings

Authors: S. Mawlood, L. Denanny, N. Watson, B. Pickard

Abstract:

DNA analysis has been widely accepted as providing valuable evidence concerning the identity of the source of biological traces. Our work has showed that DNA samples can survive on cartridges even after firing. The study also raised the possibility of determining other information such as the age of the donor. Such information may be invaluable in certain cases where spent cartridges from automatic weapons are left behind at the scene of a crime. In spite of the nature of touch evidence and exposure to high chamber temperatures during shooting, we were still capable to retrieve enough DNA for profile typing. In order to estimate age of contributor, DNA methylation levels were analyzed using EpiTect system for retrieved DNA. However, results were not conclusive, due to low amount of input DNA.

Keywords: DNA profile, DNA Methylation, fired cartridge, touch sample

Procedia PDF Downloads 452
12545 Q-Learning of Bee-Like Robots Through Obstacle Avoidance

Authors: Jawairia Rasheed

Abstract:

Modern robots are often used for search and rescue purpose. One of the key areas of interest in such cases is learning complex environments. One of the key methodologies for robots in such cases is reinforcement learning. In reinforcement learning robots learn to move the path to reach the goal while avoiding obstacles. Q-learning, one of the most advancement of reinforcement learning is used for making the robots to learn the path. Robots learn by interacting with the environment to reach the goal. In this paper simulation model of bee-like robots is implemented in NETLOGO. In the start the learning rate was less and it increased with the passage of time. The bees successfully learned to reach the goal while avoiding obstacles through Q-learning technique.

Keywords: reinforlearning of bee like robots for reaching the goalcement learning for randomly placed obstacles, obstacle avoidance through q-learning, q-learning for obstacle avoidance,

Procedia PDF Downloads 103
12544 Experimenting with Clay 3D Printing Technology to Create an Undulating Facade

Authors: Naeimehsadat Hosseininam, Rui Wang, Dishita Shah

Abstract:

In recent years, new experimental approaches with the help of the new technology have bridged the gaps between the application of natural materials and creating unconventional forms. Clay has been one of the oldest building materials in all ancient civilizations. The availability and workability of clay have contributed to the widespread application of this material around the world. The aim of this experimental research is to apply the Clay 3D printing technology to create a load bearing and visually dynamic and undulating façade. Creation of different unique pieces is the most significant goal of this research which justifies the application of 3D printing technology instead of the conventional mass industrial production. This study provides an abbreviated overview of the similar cases which have used the Clay 3D printing to generate the corresponding prototypes. The study of these cases also helps in understanding the potential and flexibility of the material and 3D printing machine in developing different forms. In the next step, experimental research carried out by 3D printing of six various options which designed considering the properties of clay as well as the methodology of them being 3D printed. Here, the ratio of water to clay (W/C) has a significant role in the consistency of the material and the workability of the clay. Also, the size of the selected nozzle impacts the shape and the smoothness of the final surface. Moreover, the results of these experiments show the limitations of clay toward forming various slopes. The most notable consequence of having steep slopes in the prototype is an unpredicted collapse which is the result of internal tension in the material. From the six initial design ideas, the final prototype selected with the aim of creating a self-supported component with unique blocks that provides a possibility of installing the insulation system within the component. Apart from being an undulated façade, the presented prototype has the potential to be used as a fence and an interior partition (double-sided). The central shaft also provides a space to run services or insulation in different parts of the wall. In parallel to present the capability and potential of the clay 3D printing technology, this study illustrates the limitations of this system in some certain areas. There are inevitable parameters such as printing speed, temperature, drying speed that need to be considered while printing each piece. Clay 3D printing technology provides the opportunity to create variations and design parametric building components with the application of the most practiced material in the world.

Keywords: clay 3D printing, material capability, undulating facade, load bearing facade

Procedia PDF Downloads 141
12543 Investigation of the Aerodynamic Characteristics of a Vertical Take-Off and Landing Mini Unmanned Aerial Vehicle Configuration

Authors: Amir Abdelqodus, Mario Shehata

Abstract:

The purpose of the paper is to model and evaluate the aerodynamic coefficients and stability derivatives of a Vertical, Take-off and Landing Unmanned Aerial Vehicle configuration (VTOL UAV), which is a fixed wing UAV and a quad-copter hybrid capable of both vertical and conventional take-off and/or landing. The aerodynamic analysis of this configuration was carried out using CFD commercial package Ansys Fluent. Also, the aerodynamic coefficients for the case of the UAV without the quad-copter is carried out analytically using MATLAB programmed codes, and the resulting data is verified using Lifting Line Theory and potential method programs. The two results are then compared to understand the effect of adding the quad-copter on the aerodynamic performance of the UAV.

Keywords: aerodynamics, CFD, potential flow, UAV, VTOL

Procedia PDF Downloads 445
12542 Designing Nickel Coated Activated Carbon (Ni/AC) Based Electrode Material for Supercapacitor Applications

Authors: Zahid Ali Ghazi

Abstract:

Supercapacitors (SCs) have emerged as auspicious energy storage devices because of their fast charge-discharge characteristics and high power densities. In the current study, a simple approach is used to coat activated carbon (AC) with a thin layer of nickel (Ni) by an electroless deposition process to enhance the electrochemical performance of the SC. The synergistic combination of large surface area and high electrical conductivity of the AC, as well as the pseudocapacitive behavior of the metallic Ni, has shown great potential to overcome the limitations of traditional SC materials. First, the materials were characterized using X-ray diffraction (XRD) for crystallography, scanning electron microscopy (SEM) for surface morphology and energy dispersion X-ray (EDX) for elemental analysis. The electrochemical performance of the nickel-coated activated carbon (Ni-AC) is systematically evaluated through various techniques, including galvanostatic charge-discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The GCD results revealed that Ni/AC has a higher specific capacitance (1559 F/g) than bare AC (222 F/g) at 1 A/g current density in a 2 M KOH electrolyte. Even at a higher current density of 20 A/g, the Ni/AC showed a high capacitance of 944 F/g as compared to 77 F/g by AC. The specific capacitance (1318 F/g) calculated from CV measurements for Ni-AC at 10mV/sec was in close agreement with GCD data. Furthermore, the bare AC exhibited a low energy of 15 Wh/kg at a power density of 356 W/kg whereas, an energy density of 111 Wh/kg at a power density of 360 W/kg was achieved by Ni/AC-850 electrode and demonstrated a long life cycle with 94% capacitance retention over 50000 charge/discharge cycles at 10 A/g. In addition, the EIS study disclosed that the Rs and Rct values of Ni/AC electrodes were much lower than those of bare AC. The superior performance of Ni/AC is mainly attributed to the presence of excessive redox active sites, large electroactive surface area and corrosive resistance properties of Ni. We believe that this study will provide new insights into the controlled coating of ACs and other porous materials with metals for developing high-performance SCs and other energy storage devices.

Keywords: supercapacitor, cyclic voltammetry, coating, energy density, activated carbon

Procedia PDF Downloads 63
12541 Spatio-Temporal Dynamic of Woody Vegetation Assessment Using Oblique Landscape Photographs

Authors: V. V. Fomin, A. P. Mikhailovich, E. M. Agapitov, V. E. Rogachev, E. A. Kostousova, E. S. Perekhodova

Abstract:

Ground-level landscape photos can be used as a source of objective data on woody vegetation and vegetation dynamics. We proposed a method for processing, analyzing, and presenting ground photographs, which has the following advantages: 1) researcher has to form holistic representation of the study area in form of a set of interlapping ground-level landscape photographs; 2) it is necessary to define or obtain characteristics of the landscape, objects, and phenomena present on the photographs; 3) it is necessary to create new or supplement existing textual descriptions and annotations for the ground-level landscape photographs; 4) single or multiple ground-level landscape photographs can be used to develop specialized geoinformation layers, schematic maps or thematic maps; 5) it is necessary to determine quantitative data that describes both images as a whole, and displayed objects and phenomena, using algorithms for automated image analysis. It is suggested to match each photo with a polygonal geoinformation layer, which is a sector consisting of areas corresponding with parts of the landscape visible in the photos. Calculation of visibility areas is performed in a geoinformation system within a sector using a digital model of a study area relief and visibility analysis functions. Superposition of the visibility sectors corresponding with various camera viewpoints allows matching landscape photos with each other to create a complete and wholesome representation of the space in question. It is suggested to user-defined data or phenomenons on the images with the following superposition over the visibility sector in the form of map symbols. The technology of geoinformation layers’ spatial superposition over the visibility sector creates opportunities for image geotagging using quantitative data obtained from raster or vector layers within the sector with the ability to generate annotations in natural language. The proposed method has proven itself well for relatively open and clearly visible areas with well-defined relief, for example, in mountainous areas in the treeline ecotone. When the polygonal layers of visibility sectors for a large number of different points of photography are topologically superimposed, a layer of visibility of sections of the entire study area is formed, which is displayed in the photographs. Also, as a result of this overlapping of sectors, areas that did not appear in the photo will be assessed as gaps. According to the results of this procedure, it becomes possible to obtain information about the photos that display a specific area and from which points of photography it is visible. This information may be obtained either as a query on the map or as a query for the attribute table of the layer. The method was tested using repeated photos taken from forty camera viewpoints located on Ray-Iz mountain massif (Polar Urals, Russia) from 1960 until 2023. It has been successfully used in combination with other ground-based and remote sensing methods of studying the climate-driven dynamics of woody vegetation in the Polar Urals. Acknowledgment: This research was collaboratively funded by the Russian Ministry for Science and Education project No. FEUG-2023-0002 (image representation) and Russian Science Foundation project No. 24-24-00235 (automated textual description).

Keywords: woody, vegetation, repeated, photographs

Procedia PDF Downloads 89
12540 Artificial Intelligence-Aided Extended Kalman Filter for Magnetometer-Based Orbit Determination

Authors: Gilberto Goracci, Fabio Curti

Abstract:

This work presents a robust, light, and inexpensive algorithm to perform autonomous orbit determination using onboard magnetometer data in real-time. Magnetometers are low-cost and reliable sensors typically available on a spacecraft for attitude determination purposes, thus representing an interesting choice to perform real-time orbit determination without the need to add additional sensors to the spacecraft itself. Magnetic field measurements can be exploited by Extended/Unscented Kalman Filters (EKF/UKF) for orbit determination purposes to make up for GPS outages, yielding errors of a few kilometers and tens of meters per second in the position and velocity of a spacecraft, respectively. While this level of accuracy shows that Kalman filtering represents a solid baseline for autonomous orbit determination, it is not enough to provide a reliable state estimation in the absence of GPS signals. This work combines the solidity and reliability of the EKF with the versatility of a Recurrent Neural Network (RNN) architecture to further increase the precision of the state estimation. Deep learning models, in fact, can grasp nonlinear relations between the inputs, in this case, the magnetometer data and the EKF state estimations, and the targets, namely the true position, and velocity of the spacecraft. The model has been pre-trained on Sun-Synchronous orbits (SSO) up to 2126 kilometers of altitude with different initial conditions and levels of noise to cover a wide range of possible real-case scenarios. The orbits have been propagated considering J2-level dynamics, and the geomagnetic field has been modeled using the International Geomagnetic Reference Field (IGRF) coefficients up to the 13th order. The training of the module can be completed offline using the expected orbit of the spacecraft to heavily reduce the onboard computational burden. Once the spacecraft is launched, the model can use the GPS signal, if available, to fine-tune the parameters on the actual orbit onboard in real-time and work autonomously during GPS outages. In this way, the provided module shows versatility, as it can be applied to any mission operating in SSO, but at the same time, the training is completed and eventually fine-tuned, on the specific orbit, increasing performances and reliability. The results provided by this study show an increase of one order of magnitude in the precision of state estimate with respect to the use of the EKF alone. Tests on simulated and real data will be shown.

Keywords: artificial intelligence, extended Kalman filter, orbit determination, magnetic field

Procedia PDF Downloads 105