Search results for: wave analysis
27996 A Practical Protection Method for Parallel Transmission-Lines Based on the Fault Travelling-Waves
Authors: Mohammad Reza Ebrahimi
Abstract:
In new restructured power systems, swift fault detection is very important. The parallel transmission-lines are vastly used in this kind of power systems because of high amount of energy transferring. In this paper, a method based on the comparison of two schemes, i.e., i) maximum magnitude of travelling-wave (TW) energy ii) the instants of maximum energy occurrence at the circuits of parallel transmission-line is proposed. Using the travelling-wave of fault in order to faulted line identification this method has noticeable operation time. Moreover, the algorithm can cover for identification of faults as external or internal faults. For an internal fault, the exact location of the fault can be estimated confidently. A lot of simulations have been done with PSCAD/EMTDC to verify the performance of the proposed algorithm.Keywords: travelling-wave, maximum energy, parallel transmission-line, fault location
Procedia PDF Downloads 17727995 EEG Signal Processing Methods to Differentiate Mental States
Authors: Sun H. Hwang, Young E. Lee, Yunhan Ga, Gilwon Yoon
Abstract:
EEG is a very complex signal with noises and other bio-potential interferences. EOG is the most distinct interfering signal when EEG signals are measured and analyzed. It is very important how to process raw EEG signals in order to obtain useful information. In this study, the EEG signal processing techniques such as EOG filtering and outlier removal were examined to minimize unwanted EOG signals and other noises. The two different mental states of resting and focusing were examined through EEG analysis. A focused state was induced by letting subjects to watch a red dot on the white screen. EEG data for 32 healthy subjects were measured. EEG data after 60-Hz notch filtering were processed by a commercially available EOG filtering and our presented algorithm based on the removal of outliers. The ratio of beta wave to theta wave was used as a parameter for determining the degree of focusing. The results show that our algorithm was more appropriate than the existing EOG filtering.Keywords: EEG, focus, mental state, outlier, signal processing
Procedia PDF Downloads 27427994 Dynamic Interaction between Two Neighboring Tunnels in a Layered Half-Space
Authors: Chao He, Shunhua Zhou, Peijun Guo
Abstract:
The vast majority of existing underground railway lines consist of twin tunnels. In this paper, the dynamic interaction between two neighboring tunnels in a layered half-space is investigated by an analytical model. The two tunnels are modelled as cylindrical thin shells, while the soil in the form of a layered half-space with two cylindrical cavities is simulated by the elastic continuum theory. The transfer matrix method is first used to derive the relationship between the plane wave vectors in arbitrary layers and the source layer. Thereafter, the wave translation and transformation are introduced to determine the plane and cylindrical wave vectors in the source layer. The solution for the dynamic interaction between twin tunnels in a layered half-space is obtained by means of the compatibility of displacements and equilibrium of stresses on the two tunnel–soil interfaces. By coupling the proposed model with a fully track model, the train-induced vibrations from twin tunnels in a multi-layered half-space are investigated. The numerical results demonstrate that the existence of a neighboring tunnel has a significant effect on ground vibrations.Keywords: underground railway, twin tunnels, wave translation and transformation, transfer matrix method
Procedia PDF Downloads 10627993 Induced Pulsation Attack Against Kalman Filter Driven Brushless DC Motor Control System
Authors: Yuri Boiko, Iluju Kiringa, Tet Yeap
Abstract:
We use modeling and simulation tools, to introduce a novel bias injection attack, named the ’Induced Pulsation Attack’, which targets Cyber Physical Systems with closed-loop controlled Brushless DC (BLDC) motor and Kalman filter driver in the feedback loop. This attack involves engaging a linear function with a constant gradient to distort the coefficient of the injected bias, which falsifies the Kalman filter estimates of the rotor’s angular speed. As a result, this manipulation interaction inside the control system causes periodic pulsations in a form of asymmetric sine wave of both current and voltage in the circuit windings, with a high magnitude. It is shown that by varying the gradient of linear function, one can control both the frequency and structure of the induced pulsations. It is also demonstrated that terminating the attack at any point leads to additional compensating effort from the controller to restore the speed to its equilibrium value. This compensation effort produces an exponentially decaying wave, which we call the ’attack withdrawal syndrome’ wave. The conditions for maximizing or minimizing the impact of the attack withdrawal syndrome are determined. Linking the termination of the attack to the end of the full period of the induced pulsation wave has been shown to nullify the attack withdrawal syndrome wave, thereby improving the attack’s covertness.Keywords: cyber-attack, induced pulsation, bias injection, Kalman filter, BLDC motor, control system, closed loop, P- controller, PID-controller, saw-function, cyber-physical system
Procedia PDF Downloads 6127992 A Portable Device for Pulse Wave Velocity Measurements
Authors: Chien-Lin Wang, Cha-Ling Ko, Tainsong Chen
Abstract:
Pulse wave velocity (PWV) of blood flow provides important information of vessel property and blood pressure which can be used to assess cardiovascular disease. However, the above measurements need expensive equipment, such as Doppler ultrasound, MRI, angiography etc. The photoplethysmograph (PPG) signals are commonly utilized to detect blood volume changes. In this study, two infrared (IR) probes are designed and placed at a fixed distance from finger base and fingertip. An analog circuit with automatic gain adjustment is implemented to get the stable original PPG signals from above two IR probes. In order to obtain the time delay precisely between two PPG signals, we obtain the pulse transit time from the second derivative of the original PPG signals. To get a portable, wireless and low power consumption PWV measurement device, the low energy Bluetooth 4.0 (BLE) and the microprocessor (Cortex™-M3) are used in this study. The PWV is highly correlated with blood pressure. This portable device has potential to be used for continuous blood pressure monitoring.Keywords: pulse wave velocity, photoplethysmography, portable device, biomedical engineering
Procedia PDF Downloads 52127991 Fast-Forward Problem in Asymmetric Double-Well Potential
Authors: Iwan Setiawan, Bobby Eka Gunara, Katshuhiro Nakamura
Abstract:
The theory to accelerate system on quantum dynamics has been constructed to get the desired wave function on shorter time. This theory is developed on adiabatic quantum dynamics which any regulation is done on wave function that satisfies Schrödinger equation. We show accelerated manipulation of WFs with the use of a parameter-dependent in asymmetric double-well potential and also when it’s influenced by electromagnetic fields.Keywords: driving potential, Adiabatic Quantum Dynamics, regulation, electromagnetic field
Procedia PDF Downloads 32927990 Relativistic Energy Analysis for Some q Deformed Shape Invariant Potentials in D Dimensions Using SUSYQM Approach
Authors: A. Suparmi, C. Cari, M. Yunianto, B. N. Pratiwi
Abstract:
D-dimensional Dirac equations of q-deformed shape invariant potentials were solved using supersymmetric quantum mechanics (SUSY QM) in the case of exact spin symmetry. The D dimensional radial Dirac equation for shape invariant potential reduces to one-dimensional Schrodinger type equation by an appropriate variable and parameter change. The relativistic energy spectra were analyzed by using SUSY QM and shape invariant properties from radial D dimensional Dirac equation that have reduced to one dimensional Schrodinger type equation. The SUSY operator was used to generate the D dimensional relativistic radial wave functions, the relativistic energy equation reduced to the non-relativistic energy in the non-relativistic limit.Keywords: D-dimensional dirac equation, non-central potential, SUSY QM, radial wave function
Procedia PDF Downloads 33527989 Millimeter Wave Antenna for 5G Mobile Communications Systems
Authors: Hind Mestouri
Abstract:
The study and simulation of a millimeter wave antenna for 5G mobile communication systems is the topic of this paper. We present at the beginning the general aspects of the 5G technology. We recall the objectives of the 5G standard, its architecture, and the parameters that characterize it. The proposed antenna model is designed using the CST Microwave Studio simulation software. Numerous methods are used at all steps of the design procedures, such as theoretical calculation of parameters, declaration of parameter values, and evaluation of the antenna through the obtained results. Initially, we were interested in the design of an antenna array at the 10 GHz frequency. Afterward, we also simulated and presented an antenna array at 2.5 GHz. For each antenna designed, a parametric study was conducted to understand and highlight the role and effects of the various parameters in order to optimize them and achieve a final efficient structure. The obtained results using CST Microwave Studio showed that the characteristics of the designed antennas (bandwidth, gain, radiation pattern) satisfy the specifications of 5G mobile communications.Keywords: 5G, antenna array, millimeter wave, 10 GHz, CST Microwave Studio
Procedia PDF Downloads 7127988 Investigating Jacket-Type Offshore Structures Failure Probability by Applying the Reliability Analyses Methods
Authors: Majid Samiee Zonoozian
Abstract:
For such important constructions as jacket type platforms, scrupulous attention in analysis, design and calculation processes is needed. The reliability assessment method has been established into an extensively used method to behavior safety calculation of jacket platforms. In the present study, a methodology for the reliability calculation of an offshore jacket platform in contradiction of the extreme wave loading state is available. Therefore, sensitivity analyses are applied to acquire the nonlinear response of jacket-type platforms against extreme waves. The jacket structure is modeled by applying a nonlinear finite-element model with regards to the tubular members' behave. The probability of a member’s failure under extreme wave loading is figured by a finite-element reliability code. The FORM and SORM approaches are applied for the calculation of safety directories and reliability indexes have been detected. A case study for a fixed jacket-type structure positioned in the Persian Gulf is studied by means of the planned method. Furthermore, to define the failure standards, equations suggested by the 21st version of the API RP 2A-WSD for The jacket-type structures’ tubular members designing by applying the mixed axial bending and axial pressure. Consequently, the effect of wave Loades in the reliability index was considered.Keywords: Jacket-Type structure, reliability, failure probability, tubular members
Procedia PDF Downloads 16427987 Investigation on a Wave-Powered Electrical Generator Consisted of a Geared Motor-Generator Housed by a Double-Cone Rolling on Concentric Circular Rails
Authors: Barenten Suciu
Abstract:
An electrical generator able to harness energy from the water waves and designed as a double-cone geared motor-generator (DCGMG), is proposed and theoretically investigated. Similar to a differential gear mechanism, used in the transmission system of the auto vehicle wheels, an angular speed differential is created between the cones rolling on two concentric circular rails. Water wave acting on the floating DCGMG produces and a gear-box amplifies the speed differential to gain sufficient torque for power generation. A model that allows computation of the speed differential, torque, and power of the DCGMG is suggested. Influence of various parameters, regarding the construction of the DCGMG, as well as the contact between the double-cone and rails, on the electro-mechanical output, is emphasized. Results obtained indicate that the generated electrical power can be increased by augmenting the mass of the double-cone, the span of the rails, the apex angle of the cones, the friction between cones and rails, the amplification factor of the gear-box, and the efficiency of the motor-generator. Such findings are useful to formulate a design methodology for the proposed wave-powered generator.Keywords: amplification of angular speed differential, circular concentric rails, double-cone, wave-powered electrical generator
Procedia PDF Downloads 14827986 Simulation of Acoustic Properties of Borate and Tellurite Glasses
Authors: M. S. Gaafar, S. Y. Marzouk, I. S. Mahmoud, S. Al-Zobaidi
Abstract:
Makishima and Mackenzie model was used to simulation of acoustic properties (longitudinal and shear ultrasonic wave velocities, elastic moduli theoretically for many tellurite and borate glasses. The model was proposed mainly depending on the values of the experimentally measured density, which are obtained before. In this search work, we are trying to obtain the values of densities of amorphous glasses (as the density depends on the geometry of the network structure of these glasses). In addition, the problem of simulating the slope of linear regression between the experimentally determined bulk modulus and the product of packing density and experimental Young's modulus, were solved in this search work. The results showed good agreement between the experimentally measured values of densities and both ultrasonic wave velocities, and those theoretically determined.Keywords: glasses, ultrasonic wave velocities, elastic modulus, Makishima & Mackenzie Model
Procedia PDF Downloads 37327985 Application of Strong Optical Feedback to Enhance the Modulation Bandwidth of Semiconductor Lasers to the Millimeter-Wave Band
Authors: Moustafa Ahmed, Ahmed Bakry, Fumio Koyama
Abstract:
We report on the use of strong external optical feedback to enhance the modulation response of semiconductor lasers over a frequency passband around modulation frequencies higher than 60 GHz. We show that this modulation enhancement is a type of photon-photon resonance (PPR) of oscillating modes in the external cavity formed between the laser and the external reflector. The study is based on a time-delay rate equation model that takes into account both the strong feedback and multiple reflections in the external cavity. We examine the harmonic and intermodulation distortions associated with single and two-tone modulations in the mm-wave band of the resonant modulation. We show that compared with solitary lasers modulated around the carrier-photon resonance frequency, the present mm-wave modulated signal has lower distortions.Keywords: semiconductor laser, optical feedback, modulation, harmonic distortion
Procedia PDF Downloads 73727984 Wave-Assisted Flapping Foil Propulsion: Flow Physics and Scaling Laws From Fluid-Structure Interaction Simulations
Authors: Rajat Mittal, Harshal Raut, Jung Hee Seo
Abstract:
Wave-assisted propulsion (WAP) systems convert wave energy into thrust using elastically mounted hydrofoils. We employ sharp-interface immersed boundary simulations to examine the effect of two key parameters on the flow physics, the fluid-structure interaction, as well as thrust performance of these systems - the stiffness of the torsional spring and the location of the rotational center. The variation in spring stiffness leads to different amplitude of pitch motion, phase difference with respect to heaving motion and thrust coefficient and we show the utility of ‘maps’ of energy exchange between the flow and the hydrofoil system, as a way to understand and predict this behavior. The Force Partitioning Method (FPM) is used to decompose the pressure forces into individual components and understand the mechanism behind increase in thrust. Next, a scaling law is presented for the thrust coefficient generated by heaving and pitching foil. The parameters within the scaling law are calculated based on direct-numerical simulations based parametric study utilized to generate the energy maps. The predictions of the proposed scaling law are then compared with those of a similar model from the literature, showing a noticeable improvement in the prediction of the thrust coefficient.Keywords: propulsion, flapping foils, hydrodynamics, wave power
Procedia PDF Downloads 4927983 Time Varying Crustal Anisotropy at Whakaari/White Island Volcano
Authors: M. Dagim Yoseph, M. K. Savage, A. D. Jolly, C. J. Ebinger
Abstract:
Whakaari/White Island has been the most active New Zealand volcano in the 21st century, producing small phreatic and phreatomagmatic eruptions, which are hard to predict. The most recent eruption occurred in 2019, tragically claiming the lives of 22 individuals and causing numerous injuries. We employed shear-wave splitting analyses to investigate variations in anisotropy between 2018 and 2020, during quiescence, unrest, and the eruption. We examined spatial and temporal variations in 3499 shear-wave splitting and 2656 V_p/V_s ratio measurements. Comparing shear-wave splitting parameters from similar earthquake paths across different times indicates that the observed temporal changes are unlikely to result from variations in earthquake paths through media with spatial variability. Instead, these changes may stem from variations in anisotropy over time, likely caused by changes in crack alignment due to stress or varying fluid content.Keywords: background seismic waves, fast orientations, seismic anisotropy, V_p/V_s ratio
Procedia PDF Downloads 3327982 A New Correlation Between SPT-N and SSPT-N values for Various Soil Types in Peninsular Malaysia
Authors: Abdull Halim
Abstract:
The Standard Penetration Test (SPT-N) is the most common in situ test for soil investigations. The Shearing Seismic Standard Penetration Test (SSPT-N), on the other hand, is a new method using shearing wave with propagation exponent equation between the shearing wave, Vs., and hardness, N values without any need for borehole data. Due to the fast and accurate results that can be obtained, the SSPT has found many applications such as in the field rectification buried pipe line, the acid tank settlement and foundation design analyses, and the quality control assessment. Many geotechnical regimes and properties have attempted to correlate both the SSPT and the SPT-N values. Various foundation design methods have been developed based on the outcomes of these tests. Hence, it is pertinent to correlate these tests so that either one of the test can be used in the absence of the other, especially for preliminary evaluation and design purposes. The primary purpose of this study was to investigate the relationship between the SSPT-N and SPT-N values for different types of cohesive soil in Peninsular Malaysia. Data were collected from four different sites, and the correlations were established between the hardness N values, principal stress-strain Mohr circle curve, cohesion, friction angle and vertical effective stress. A positive exponent relationship was found between the shearing wave, sVs., and the hardness N values of the soil. In general, the SSPT-N value was slightly lower than the SPT-N value due to the upper limit boundary of the soil layer.Keywords: InsituSoil determination; shearing wave; hardness; correlation, SSPT-N, SPT-N
Procedia PDF Downloads 17427981 Gait Biometric for Person Re-Identification
Authors: Lavanya Srinivasan
Abstract:
Biometric identification is to identify unique features in a person like fingerprints, iris, ear, and voice recognition that need the subject's permission and physical contact. Gait biometric is used to identify the unique gait of the person by extracting moving features. The main advantage of gait biometric to identify the gait of a person at a distance, without any physical contact. In this work, the gait biometric is used for person re-identification. The person walking naturally compared with the same person walking with bag, coat, and case recorded using longwave infrared, short wave infrared, medium wave infrared, and visible cameras. The videos are recorded in rural and in urban environments. The pre-processing technique includes human identified using YOLO, background subtraction, silhouettes extraction, and synthesis Gait Entropy Image by averaging the silhouettes. The moving features are extracted from the Gait Entropy Energy Image. The extracted features are dimensionality reduced by the principal component analysis and recognised using different classifiers. The comparative results with the different classifier show that linear discriminant analysis outperforms other classifiers with 95.8% for visible in the rural dataset and 94.8% for longwave infrared in the urban dataset.Keywords: biometric, gait, silhouettes, YOLO
Procedia PDF Downloads 16627980 The Plasma Additional Heating Systems by Electron Cyclotron Waves
Authors: Ghoutia Naima Sabri, Tayeb Benouaz
Abstract:
The interaction between wave and electron cyclotron movement when the electron passes through a layer of resonance at a fixed frequency results an Electron Cyclotron (EC) absorption in Tokamak plasma and dependent magnetic field. This technique is the principle of additional heating (ECRH) and the generation of non-inductive current drive (ECCD) in modern fusion devices. In this paper we are interested by the problem of EC absorption which used a microscopic description of kinetic theory treatment versus the propagation which used the cold plasma description. The power absorbed depends on the optical depth which in turn depends on coefficient of absorption and the order of the excited harmonic for O-mode or X-mode. There is another possibility of heating by dissipation of Alfven waves, based on resonance of cold plasma waves, the shear Alfven wave (SW) and the compressional Alfven wave (FW). Once the (FW) power is coupled to (SW), it stays on the magnetic surface and dissipates there, which cause the heating of bulk plasmas.Keywords: electron cyclotron, heating, plasma, tokamak
Procedia PDF Downloads 50527979 Computational Fluid Dynamics Analysis of Convergent–Divergent Nozzle and Comparison against Theoretical and Experimental Results
Authors: Stewart A. Keir, Faik A. Hamad
Abstract:
This study aims to use both analytical and experimental methods of analysis to examine the accuracy of Computational Fluid Dynamics (CFD) models that can then be used for more complex analyses, accurately representing more elaborate flow phenomena such as internal shockwaves and boundary layers. The geometry used in the analytical study and CFD model is taken from the experimental rig. The analytical study is undertaken using isentropic and adiabatic relationships and the output of the analytical study, the 'shockwave location tool', is created. The results from the analytical study are then used to optimize the redesign an experimental rig for more favorable placement of pressure taps and gain a much better representation of the shockwaves occurring in the divergent section of the nozzle. The CFD model is then optimized through the selection of different parameters, e.g. turbulence models (Spalart-Almaras, Realizable k-epsilon & Standard k-omega) in order to develop an accurate, robust model. The results from the CFD model can then be directly compared to experimental and analytical results in order to gauge the accuracy of each method of analysis. The CFD model will be used to visualize the variation of various parameters such as velocity/Mach number, pressure and turbulence across the shock. The CFD results will be used to investigate the interaction between the shock wave and the boundary layer. The validated model can then be used to modify the nozzle designs which may offer better performance and ease of manufacture and may present feasible improvements to existing high-speed flow applications.Keywords: CFD, nozzle, fluent, gas dynamics, shock-wave
Procedia PDF Downloads 22827978 FPGA Implementation of a Marginalized Particle Filter for Delineation of P and T Waves of ECG Signal
Authors: Jugal Bhandari, K. Hari Priya
Abstract:
The ECG signal provides important clinical information which could be used to pretend the diseases related to heart. Accordingly, delineation of ECG signal is an important task. Whereas delineation of P and T waves is a complex task. This paper deals with the Study of ECG signal and analysis of signal by means of Verilog Design of efficient filters and MATLAB tool effectively. It includes generation and simulation of ECG signal, by means of real time ECG data, ECG signal filtering and processing by analysis of different algorithms and techniques. In this paper, we design a basic particle filter which generates a dynamic model depending on the present and past input samples and then produces the desired output. Afterwards, the output will be processed by MATLAB to get the actual shape and accurate values of the ranges of P-wave and T-wave of ECG signal. In this paper, Questasim is a tool of mentor graphics which is being used for simulation and functional verification. The same design is again verified using Xilinx ISE which will be also used for synthesis, mapping and bit file generation. Xilinx FPGA board will be used for implementation of system. The final results of FPGA shall be verified with ChipScope Pro where the output data can be observed.Keywords: ECG, MATLAB, Bayesian filtering, particle filter, Verilog hardware descriptive language
Procedia PDF Downloads 35827977 Effectiveness of Shock Wave Therapy Versus Intermittent Mechanical Traction on Mechanical Low Back Pain and Disabilities
Authors: Ahmed Assem Abd El Rahim
Abstract:
Background: Mechanical low back pain is serious physical and social health problem. Purpose: To examine impact of shock wave therapy versus intermittent mechanical traction on mechanical LBP, and disabilities. Subjects: 60 mechanical LBP male studied cases years old 20-35 years were assigned randomly into 3 groups, Picked up from Sohag university orthopedic hospital outpatient clinic. Methods: (Study Group) A: 20 studied cases underwent shock wave therapy plus conventional physical therapy. (Study Group) B: twenty studied cases underwent intermittent mechanical traction plus conventional physical therapy. (Control Group) C: 20 patients underwent conventional physical therapy alone. Three sessions were applied weekly for four weeks. Pain was quantified using McGill Pain Questionnaire, Roland Morris Disability Questionnaire was used for measuring disability, and the ROM was evaluated by (BROM) device pre- & post-therapy. Results: Groups (A, B & C) found a reduction in pain & disability & rise in their in flexion and extension ROM after end of 4 weeks of program. Mean values of pain scale after therapy were 15.3, 9.47, and 23.07 in groups A, B, & C. mean values of Disability scale after therapy were 8.44, 4.87, 11.8in groups A, B & C. mean values of ROM of flexion were 25.53, 29.06, & 23.9 in groups A, B & C. mean values of ROM of extension were 11.73, 15.53 & 9.85 in groups A, B & C. studied cases who received intermittent mechanical traction & conventional physical therapy (group B), found reduction in pain & disability & improvement in ROM of flexion & extension value (P<0.001) after therapy program. Conclusion: Shock wave therapy and intermittent mechanical traction, as well as conventional physical treatment, can be beneficial in studied cases with mechanical LBP.Keywords: mechanical low back pain, shock wave, mechanical, low back pain
Procedia PDF Downloads 4827976 The Concerns and Recommendations of Informal and Professional Caregivers for COVID-19 Policy for Homecare and Long-Term Care For People with Dementia: A Qualitative Study
Authors: Hanneke J. A. Smaling, Mandy Visser
Abstract:
One way to reduce the risk of COVID-19 infection is by preventing close interpersonal contact with distancing measures. These social distancing measures presented challenges to the health and wellbeing of people with dementia and their informal and professional caregivers. This study describes the concerns and recommendations of informal and professional caregivers for COVID-19 policy for home care and long-term care for people with dementia during the first and second COVID-19 wave in the Netherlands. In this qualitative interview study, 20 informal caregivers and 20 professional caregivers from home care services and long-term care participated. Interviews were analyzed using an inductive thematic analysis approach. Both informal and professional caregivers worried about getting infected or infecting others with COVID-19, the consequences of the distancing measures, and quality of care. There was a general agreement that policy in the second wave was better informed compared to the first wave. At an organizational level, the policy was remarkably flexible. Recommendations were given for dementia care (need to offer meaningful activities, improve the organization of care, more support for informal caregivers), policy (national vs. locally organization, social isolation measures, visitor policy), and communication. Our study contributes to the foundation of future care decisions by (inter)national policymakers, politicians, and healthcare organizations during the course of the COVID-19 pandemic, underlining the need for balance between safety and autonomy for people with dementia.Keywords: covid-19, dementia, home care, long-term care, policy
Procedia PDF Downloads 12727975 Comparison of Number of Waves Surfed and Duration Using Global Positioning System and Inertial Sensors
Authors: João Madureira, Ricardo Lagido, Inês Sousa, Fraunhofer Portugal
Abstract:
Surf is an increasingly popular sport and its performance evaluation is often qualitative. This work aims at using a smartphone to collect and analyze the GPS and inertial sensors data in order to obtain quantitative metrics of the surfing performance. Two approaches are compared for detection of wave rides, computing the number of waves rode in a surfing session, the starting time of each wave and its duration. The first approach is based on computing the velocity from the Global Positioning System (GPS) signal and finding the velocity thresholds that allow identifying the start and end of each wave ride. The second approach adds information from the Inertial Measurement Unit (IMU) of the smartphone, to the velocity thresholds obtained from the GPS unit, to determine the start and end of each wave ride. The two methods were evaluated using GPS and IMU data from two surfing sessions and validated with similar metrics extracted from video data collected from the beach. The second method, combining GPS and IMU data, was found to be more accurate in determining the number of waves, start time and duration. This paper shows that it is feasible to use smartphones for quantification of performance metrics during surfing. In particular, detection of the waves rode and their duration can be accurately determined using the smartphone GPS and IMU.Keywords: inertial measurement unit (IMU), global positioning system (GPS), smartphone, surfing performance
Procedia PDF Downloads 39427974 A Longitudinal Survey Study of Izmir Commuter Rail System (IZBAN)
Authors: Samet Sen, Yalcin Alver
Abstract:
Before Izmir Commuter Rail System (IZBAN), most of the respondents along the railway were making their trips by city buses, minibuses or private cars. After IZBAN was put into service, some people changed their previous trip behaviors and they started travelling by IZBAN. Therefore a big travel demand in IZBAN occurred. In this study, the characteristics of passengers and their trip behaviors are found out based on the longitudinal data conducted via two wave trip surveys. Just after one year from IZBAN's opening, the first wave of the surveys was carried out among 539 passengers at six stations during morning peak hours between 07.00 am-09.30 am. The second wave was carried out among 669 passengers at the same six stations two years after the first wave during the same morning peak hours. As a result of this study, the respondents' socio-economic specifications, the distribution of trips by region, the impact of IZBAN on transport modes, the changes in travel time and travel cost and satisfaction data were obtained. These data enabled to compare two waves and explain the changes in socio-economic factors and trip behaviors. In both waves, 10 % of the respondents stopped driving their own cars and they started to take IZBAN. This is an important development in solving traffic problems. More public transportation means less traffic congestion.Keywords: commuter rail system, comparative study, longitudinal survey, public transportation
Procedia PDF Downloads 42327973 Linear Stability Analysis of a Regularized Two-Fluid Model for Unstable Gas-Liquid Flows in Long Hilly Terrain Pipelines
Authors: David Alejandro Lazo-Vasquez, Jorge Luis Balino
Abstract:
In the petroleum industry, multiphase flow occurs when oil, gas, and water are transported in the same pipe through large pipeline systems. The flow can take different patterns depending on parameters like fluid velocities, pipe diameter, pipe inclination, and fluid properties. Mainly, intermittent flow is produced by the natural propagation of short and long waves, according to the Kelvin-Helmholtz Stability Theory. To model stratified flow and the onset of intermittent flow, it is crucial to have knowledge of short and long waves behavior. The two-fluid model, frequently employed for characterizing multiphase systems, becomes ill-posed for high liquid and gas velocities and large inclination angles, for short waves can develop infinite growth rates. We are interested in focusing attention on long-wave instability, which leads to the production of roll waves that may grow and result in the transition from stratified flow to intermittent flow. In this study, global and local linear stability analyses for dynamic and kinematic stability criteria predict the regions of stability of the flow for different pipe inclinations and fluid velocities in regularized and non-regularized systems, concurrently. It was possible to distinguish when: wave growth rates are absolutely bounded (stable stratified smooth flow), waves have finite growth rates (unstable stratified wavy flow), and when the equation system becomes elliptic and hyperbolization is needed. In order to bound short wave growth rates and regularize the equation system, we incorporated some lower and higher-order terms like interfacial drag and surface tension, respectively.Keywords: linear stability analysis, multiphase flow, onset of slugging, two-fluid model regularization
Procedia PDF Downloads 12627972 Wall Pressure Fluctuations in Naturally Developing Boundary Layer Flows on Axisymmetric Bodies
Authors: Chinsuk Hong
Abstract:
This paper investigates the characteristics of wall pressure fluctuations in naturally developing boundary layer flows on axisymmetric bodies experimentally. The axisymmetric body has a modified ellipsoidal blunt nose. Flush-mounted microphones are used to measure the wall pressure fluctuations in the boundary layer flow over the body. The measurements are performed in a low noise wind tunnel. It is found that the correlation between the flow regime and the characteristics of the pressure fluctuations is distinct. The process from small fluctuation in laminar flow to large fluctuation in turbulent flow is investigated. Tollmien-Schlichting wave (T-S wave) is found to generate and develop in transition. Because of the T-S wave, the wall pressure fluctuations in the transition region are higher than those in the turbulent boundary layer.Keywords: wall pressure fluctuation, boundary layer flow, transition, turbulent flow, axisymmetric body, flow noise
Procedia PDF Downloads 34727971 Interaction between Trapezoidal Hill and Subsurface Cavity under SH Wave Incidence
Authors: Yuanrui Xu, Zailin Yang, Yunqiu Song, Guanxixi Jiang
Abstract:
It is an important subject of seismology on the influence of local topography on ground motion during earthquake. In mountainous areas with complex terrain, the construction of the tunnel is often the most effective transportation scheme. In these projects, the local terrain can be simplified into hills with different shapes, and the underground tunnel structure can be regarded as a subsurface cavity. The presence of the subsurface cavity affects the strength of the rock mass and changes the deformation and failure characteristics. Moreover, the scattering of the elastic waves by underground structures usually interacts with local terrains, which leads to a significant influence on the surface displacement of the terrains. Therefore, it is of great practical significance to study the surface displacement of local terrains with underground tunnels in earthquake engineering and seismology. In this work, the region is divided into three regions by the method of region matching. By using the fractional Bessel function and Hankel function, the complex function method, and the wave function expansion method, the wavefield expression of SH waves is introduced. With the help of a constitutive relation between the displacement and the stress components, the hoop stress and radial stress is obtained subsequently. Then, utilizing the continuous condition at different region boundaries, the undetermined coefficients in wave fields are solved by the Fourier series expansion and truncation of the finite term. Finally, the validity of the method is verified, and the surface displacement amplitude is calculated. The surface displacement amplitude curve is discussed in the numerical results. The results show that different parameters, such as radius and buried depth of the tunnel, wave number, and incident angle of the SH wave, have a significant influence on the amplitude of surface displacement. For the underground tunnel, the increase of buried depth will make the response of surface displacement amplitude increases at first and then decreases. However, the increase of radius leads the response of surface displacement amplitude to appear an opposite phenomenon. The increase of SH wave number can enlarge the amplitude of surface displacement, and the change of incident angle can obviously affect the amplitude fluctuation.Keywords: method of region matching, scattering of SH wave, subsurface cavity, trapezoidal hill
Procedia PDF Downloads 12627970 Post-Earthquake Damage Detection Using System Identification with a Pair of Seismic Recordings
Authors: Lotfi O. Gargab, Ruichong R. Zhang
Abstract:
A wave-based framework is presented for modeling seismic motion in multistory buildings and using measured response for system identification which can be utilized to extract important information regarding structure integrity. With one pair of building response at two locations, a generalized model response is formulated based on wave propagation features and expressed as frequency and time response functions denoted, respectively, as GFRF and GIRF. In particular, GIRF is fundamental in tracking arrival times of impulsive wave motion initiated at response level which is dependent on local model properties. Matching model and measured-structure responses can help in identifying model parameters and infer building properties. To show the effectiveness of this approach, the Millikan Library in Pasadena, California is identified with recordings of the Yorba Linda earthquake of September 3, 2002.Keywords: system identification, continuous-discrete mass modeling, damage detection, post-earthquake
Procedia PDF Downloads 36627969 Wavelet Method for Numerical Solution of Fourth Order Wave Equation
Authors: A. H. Choudhury
Abstract:
In this paper, a highly accurate numerical method for the solution of one-dimensional fourth-order wave equation is derived. This hyperbolic problem is solved by using semidiscrete approximations. The space direction is discretized by wavelet-Galerkin method, and the time variable is discretized by using Newmark schemes.Keywords: hyperbolic problem, semidiscrete approximations, stability, Wavelet-Galerkin Method
Procedia PDF Downloads 31027968 Optimization of Wavy Channel Using Genetic Algorithm
Authors: Yue-Tzu Yang, Peng-Jen Chen
Abstract:
The present study deals with the numerical optimization of wavy channel with the help of genetic algorithm (GA). Three design variables related to the wave amplitude (A), the wavelength (λ) and the channel aspect ratio (α) are chosen and their ranges are decided through preliminary calculations of three-dimensional Navier-stokes and energy equations. A parametric study is also performed to show the effects of different design variables on the overall performance of the wavy channel. Objective functions related to the heat transfer and pressure drop, performance factor (PF) is formulated to analyze the performance of the wavy channel. The numerical results show that the wave amplitude and the channel aspect ratio have significant effects on the thermal performance. It can improve the performance of the wavy channels by increasing wave amplitude or decreasing the channel aspect ratio. Increasing wavelengths have no significant effects on the heat transfer performance.Keywords: wavy channel, genetic algorithm, optimization, numerical simulation
Procedia PDF Downloads 28827967 On the Internal Structure of the ‘Enigmatic Electrons’
Authors: Natarajan Tirupattur Srinivasan
Abstract:
Quantum mechanics( QM) and (special) relativity (SR) have indeed revolutionized the very thinking of physicists, and the spectacular successes achieved over a century due to these two theories are mind-boggling. However, there is still a strong disquiet among some physicists. While the mathematical structure of these two theories has been established beyond any doubt, their physical interpretations are still being contested by many. Even after a hundred years of their existence, we cannot answer a very simple question, “What is an electron”? Physicists are struggling even now to come to grips with the different interpretations of quantum mechanics with all their ramifications. However, it is indeed strange that the (special) relativity theory of Einstein enjoys many orders of magnitude of “acceptance”, though both theories have their own stocks of weirdness in the results, like time dilation, mass increase with velocity, the collapse of the wave function, quantum jump, tunnelling, etc. Here, in this paper, it would be shown that by postulating an intrinsic internal motion to these enigmatic electrons, one can build a fairly consistent picture of reality, revealing a very simple picture of nature. This is also evidenced by Schrodinger’s ‘Zitterbewegung’ motion, about which so much has been written. This leads to a helical trajectory of electrons when they move in a laboratory frame. It will be shown that the helix is a three-dimensional wave having all the characteristics of our familiar 2D wave. Again, the helix, being a geodesic on an imaginary cylinder, supports ‘quantization’, and its representation is just the complex exponentials matching with the wave function of quantum mechanics. By postulating the instantaneous velocity of the electrons to be always ‘c’, the velocity of light, the entire relativity comes alive, and we can interpret the ‘time dilation’, ‘mass increase with velocity’, etc., in a very simple way. Thus, this model unifies both QM and SR without the need for a counterintuitive postulate of Einstein about the constancy of the velocity of light for all inertial observers. After all, if the motion of an inertial frame cannot affect the velocity of light, the converse that this constant also cannot affect the events in the frame must be true. But entire relativity is about how ‘c’ affects time, length, mass, etc., in different frames.Keywords: quantum reconstruction, special theory of relativity, quantum mechanics, zitterbewegung, complex wave function, helix, geodesic, Schrodinger’s wave equations
Procedia PDF Downloads 62