Search results for: shifted Jacobi polynomials
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 365

Search results for: shifted Jacobi polynomials

305 Uncertainty Quantification of Fuel Compositions on Premixed Bio-Syngas Combustion at High-Pressure

Authors: Kai Zhang, Xi Jiang

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Effect of fuel variabilities on premixed combustion of bio-syngas mixtures is of great importance in bio-syngas utilisation. The uncertainties of concentrations of fuel constituents such as H2, CO and CH4 may lead to unpredictable combustion performances, combustion instabilities and hot spots which may deteriorate and damage the combustion hardware. Numerical modelling and simulations can assist in understanding the behaviour of bio-syngas combustion with pre-defined species concentrations, while the evaluation of variabilities of concentrations is expensive. To be more specific, questions such as ‘what is the burning velocity of bio-syngas at specific equivalence ratio?’ have been answered either experimentally or numerically, while questions such as ‘what is the likelihood of burning velocity when precise concentrations of bio-syngas compositions are unknown, but the concentration ranges are pre-described?’ have not yet been answered. Uncertainty quantification (UQ) methods can be used to tackle such questions and assess the effects of fuel compositions. An efficient probabilistic UQ method based on Polynomial Chaos Expansion (PCE) techniques is employed in this study. The method relies on representing random variables (combustion performances) with orthogonal polynomials such as Legendre or Gaussian polynomials. The constructed PCE via Galerkin Projection provides easy access to global sensitivities such as main, joint and total Sobol indices. In this study, impacts of fuel compositions on combustion (adiabatic flame temperature and laminar flame speed) of bio-syngas fuel mixtures are presented invoking this PCE technique at several equivalence ratios. High-pressure effects on bio-syngas combustion instability are obtained using detailed chemical mechanism - the San Diego Mechanism. Guidance on reducing combustion instability from upstream biomass gasification process is provided by quantifying the significant contributions of composition variations to variance of physicochemical properties of bio-syngas combustion. It was found that flame speed is very sensitive to hydrogen variability in bio-syngas, and reducing hydrogen uncertainty from upstream biomass gasification processes can greatly reduce bio-syngas combustion instability. Variation of methane concentration, although thought to be important, has limited impacts on laminar flame instabilities especially for lean combustion. Further studies on the UQ of percentage concentration of hydrogen in bio-syngas can be conducted to guide the safer use of bio-syngas.

Keywords: bio-syngas combustion, clean energy utilisation, fuel variability, PCE, targeted uncertainty reduction, uncertainty quantification

Procedia PDF Downloads 275
304 Breastfeeding Experiences of Nutritionist who are Mothers in Quito- Ecuador

Authors: Maria Jose Mendoza Gordillo

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Introduction: Research regarding breastfeeding is devoted to how essential breastfeeding is to guarantee wellbeing for the mother and the baby from a medical standpoint relegating the cultural, material and social barriers for breastfeeding. Consequently, worldwide breastfeeding rates are low, and Ecuador is not the exception, especially among working mothers. Worldwide, health care providers have low rates of breastfeeding due to several barriers to lactation, such as the work schedule, a lack of private places for pumping while at work, and negative emotions. Goals and Methods: This study aimed to explore how do Ecuadorian women embrace their identities as nutritionists and mothers within their breastfeeding experience. The primary data come from 20 synchronous semi-structured interviews, which follow a topic guide. The interviews were recorded and transcribed verbatim. The data analysis followed the Phronetic Iterative Approach. Results: Women shifted the preconceived idea of the ideal breastfeeding that came from the medicalized discourse of breastfeeding, and that was constructed in their training as nutritionists. Although these women believe that breast milk and breastfeeding is the best way to feed a baby, the internalized ideal of breastfeeding shifted through the experience of motherhood. When these women developed their identity as mothers, they understood that the ideal breastfeeding is different from the medicalized discourse. Although they have that clash between the ideal and the external reality, they continued breastfeeding their babies and those experiences made them improve their professional practice. Conclusions: The narratives that women shared illustrate how complex it was to manage the different roles and identities that they wanted to fulfill to keep their identity of a good mother who breastfeeds her baby and, at the same time, a good healthcare provider identity. The process of breastfeeding for this group of women who are mothers and healthcare professionals appears to be a unique relational and identity negotiation process.

Keywords: breastfeeding, identity, nutritionist, qualitative

Procedia PDF Downloads 179
303 Analysis of Transverse Vibrations in Uniform Beams Subject to Different End Restraints

Authors: Falek Kamel

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Free vibration analysis of beams, based on the assumptions of Bernoulli-Euler theory, has been extensively studied. Many research works have focused on the study of transverse vibrations under the application of different boundary conditions where different theories have been applied. The stiffness and mass matrices considered are those obtained by assembling those resulting from the use of the finite element method. The Jacobi method has been used to solve the eigenvalue problem. These well-known concepts have been applied to the study of beams with constant geometric and mechanical characteristics having one to two overhangs with variable lengths. Murphy studied, by an algebraic solution approach, a simply supported beam with two overhangs of arbitrary length, allowing for an experimental determination of the elastic modulus E. The advantage of our article is that it offers the possibility of extending this approach to many interesting problems formed by transversely vibrating beams with various end constraints.

Keywords: beam, finite element, transverse vibrations, end restreint, Bernoulli-Euler theory

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302 Analysis of Pangasinan State University: Bayambang Students’ Concerns Through Social Media Analytics and Latent Dirichlet Allocation Topic Modelling Approach

Authors: Matthew John F. Sino Cruz, Sarah Jane M. Ferrer, Janice C. Francisco

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COVID-19 pandemic has affected more than 114 countries all over the world since it was considered a global health concern in 2020. Different sectors, including education, have shifted to remote/distant setups to follow the guidelines set to prevent the spread of the disease. One of the higher education institutes which shifted to remote setup is the Pangasinan State University (PSU). In order to continue providing quality instructions to the students, PSU designed Flexible Learning Model to still provide services to its stakeholders amidst the pandemic. The model covers the redesigning of delivering instructions in remote setup and the technology needed to support these adjustments. The primary goal of this study is to determine the insights of the PSU – Bayambang students towards the remote setup implemented during the pandemic and how they perceived the initiatives employed in relation to their experiences in flexible learning. In this study, the topic modelling approach was implemented using Latent Dirichlet Allocation. The dataset used in the study. The results show that the most common concern of the students includes time and resource management, poor internet connection issues, and difficulty coping with the flexible learning modality. Furthermore, the findings of the study can be used as one of the bases for the administration to review and improve the policies and initiatives implemented during the pandemic in relation to remote service delivery. In addition, further studies can be conducted to determine the overall sentiment of the other stakeholders in the policies implemented at the University.

Keywords: COVID-19, topic modelling, students’ sentiment, flexible learning, Latent Dirichlet allocation

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301 Lactational Amenorrhea Method for Family Planning: An Evaluation of Compliance in the Philippines

Authors: Ellen Bautista, Rebecca M. Flueckiger, Easter Dasmarinas, Rajeev Colaco, Fulbert Alec R. Gillego, Alma M. Lozada, Cristina Bisson

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Lactational Amenorrhea Method (LAM) for family planning is at least 98% effective at preventing pregnancy when all criteria are met; (1) the mother is exclusively or nearly exclusively breastfeeding, (2) the mother is amenorrheic (not menstruating), and (3) the baby is six months old or younger. LAM is particularly suited for women interested in family planning accepted by religious authorities. As a majority catholic nation, LAM is a common and accepted form of family planning in the Philippines. The USAID funded, LuzonHealth project conducted a prospective evaluation in Legazpi City to inform the enhancement of guidelines aimed at increasing LAM compliance and encouraging a second form of contraceptive once LAM protection expires. LAM compliance, reasons for non-compliance, family planning referral and uptake of secondary modern family planning methods were tracked over a nine-month period among 521 postpartum women. The evaluation found that at three months postpartum, 97% of women either met LAM criteria or had shifted to a non-LAM modern family planning method. In month six 87% of women no longer met LAM criteria and of these only 35% had shifted to an alternative modern family planning method. This means that at six-months postpartum 65% of the women in this evaluation were not protected against pregnancy through modern family planning methods. By postpartum month nine, 70% of the women had been referred to family planning counseling, yet of those referred only 34% reported using modern family planning methods. This evaluation clearly indicates scale-up of non-LAM modern family planning does not sufficiently complement the scale-down of LAM compliance. There is a need to increase client knowledge and understanding of LAM as a temporary family planning method with a strong focus on preparing to shift to another form of modern family planning once LAM protection expires. Additionally, there is great need to restructure the referral mechanism to ensure efficacy and quality of care.

Keywords: Philippines, family planning, lactational amenorrhea method, contraceptives

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300 Exploring Identity of Female British Pakistani Student with Shifting and Re-shifting of Cultures

Authors: Haleema Sadia

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The study is aimed at exploring the identity construction of female British born Pakistani postgraduate student who shifted to Pakistan at the age of 12, stayed there for 8 years and re-shifted to UK for Higher Education. Research questions are: 1. What is the academic and socio-cultural background of the participant prior to joining the UoM as a postgrad student? 2. How the participant talk, see herself and act in relation to cultural and social norms and practices? Participant’ identity is explored through positioning theory of Holland et al. (1998), referring to the ways people understand and enact their social positions in the figured world. The research is a case study based on narrative interview of Shabana, a British-born Pakistani female postgraduate student, who has recently joined the university of Manchester. Shabana received her primary education in UK during the first twelve years of her life. She is the youngest among the three sisters, with only one brother younger to her. Her father, although not well educated is a successful entrepreneur, maintaining offices in UK and Pakistan. Her mother is a housewife with no formal education. Shabana’s elder sister got involved in a relationship with a Pakistani boy against cultural norms of arranged marriage. Resultantly the three sisters were shifted to Pakistan to be equated with socio-religious norms. Shabana termed her first year in Pakistan as disgusting and she hated her father for the decision. However after a year’s time and shifting from an orthodox city to the provincial capital Lahore, she developed liking for the Pakistani culture. She gradually developed a new socio-religious identity during her stay, which she expressed as a turning point in her life. After completing O level Shabana returned back to UK and joined the University of Hull as undergraduate Student. At Hull she remained isolated, missed the religious environment and relished the memories of Lahore. She would visit Pakistan almost three times a year. After obtaining her BSc degree from Hull she went back to Pakistan. Soon after she decided to improve her academic qualification. She came to UK to join her parents and got admission in the MSc chemistry program at UoM. Presently Shabana talks about the dominant role of male members in the family culture in decision-making. She strongly feels to struggle hard and attain equal status with males in education, employment, earning, authority and freedom. She sees herself in a position to share the authority with her (would be) husband in important family and other matters. Shabana has developed a new identity of a mix of both Pakistani and UK culture. She is appreciative of the socio-cultural values of UK while still regarding the cultural and religious values of Pakistan in high esteem.

Keywords: postgraduate students, identity construction, cultural shifts, female british pakistani student

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299 Military Bases and Prostitution: Olongapo City after the Bases

Authors: Karl Gerrard Tiu See

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Military bases are an indelible mark of prolonged US defense relationships in the Pacific. Bases like the Subic Naval Base in Olongapo City have irreversible consequences for their host communities, not all of which are positive. One consequence the Subic Naval Base had for Olongapo City was the rise of vibrant sex industry. While the Philippine Senate voted to remove US bases like Subic in 1991, the question remains as to why did prostitution not end after the bases pull-out? To answer this question, the study used an institutionalist lens coupled with focus group discussions from the sex industry. It found that prostitution persisted due to two main reasons. The first was that like Olongapo City; the sex industry successfully shifted its reliance from the military to foreign tourism. The second was that agreements such as the 1996 Visiting Forces Agreement (VFA) ensured that the sex industry continued to receive US military clientele. With the contextual factors as the backdrop, this study used the Theory of Institutional Change to study institutions pivotal in altering Olongapo City and its sex industry after Subic Naval Base. These include local government, civil society actors such as NGOs, and the city’s economic base. The study found that policy such as the VFA allowed the bases period status quo to revive (Symbionts). This led to renewed exploitation from the military presence coupled with foreign tourism (Opportunists). The local government, however, shifted focus away from base reliance which allowed a reinvigorated civil society to effect a gradual change (Subversives). Furthermore, uncertainties like rising HIV incidence, abandoned children born from US soldiers, and the Enhanced Defence Cooperation Agreement (EDCA) remain to change the sex industry’s future, for better or worse.

Keywords: Philippine-USA defence relations, overseas USA basing, 1991 Philippine-USA bases pull-out, Olongapo city, Subic naval base, institutional change

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298 Study on a Family of Optimal Fourth-Order Multiple-Root Solver

Authors: Young Hee Geum

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In this paper,we develop the complex dynamics of a family of optimal fourth-order multiple-root solvers and plot their basins of attraction. Mobius conjugacy maps and extraneous fixed points applied to a prototype quadratic polynomial raised to the power of the known integer multiplicity m are investigated. A 300 x 300 uniform grid centered at the origin covering 3 x 3 square region is chosen to visualize the initial values on each basin of attraction in accordance with a coloring scheme based on their dynamical behavior. The illustrative basins of attractions applied to various test polynomials and the corresponding statistical data for convergence are shown to confirm the theoretical convergence.

Keywords: basin of attraction, conjugacy, fourth-order, multiple-root finder

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297 Frobenius Manifolds Pairing and Invariant Theory

Authors: Zainab Al-Maamari, Yassir Dinar

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The orbit space of an irreducible representation of a finite group is a variety with the ring of invariant polynomials as a coordinate ring. The invariant ring is a polynomial ring if and only if the representation is a reflection representation. Boris Dubrovin shows that the orbits spaces of irreducible real reflection representations acquire the structure of polynomial Frobenius manifolds. Dubrovin's method was also used to construct different examples of Frobenius manifolds on certain reflection representations. By successfully applying Dubrovin’s method on non-polynomial invariant rings of linear representations of dicyclic groups, it gives some results that magnify the relation between invariant theory and Frobenius manifolds.

Keywords: invariant ring, Frobenius manifold, inversion, representation theory

Procedia PDF Downloads 98
296 A Survey on Internet of Things and Fog Computing as a Platform for Internet of Things

Authors: Samira Kalantary, Sara Taghipour, Mansoure Ghias Abadi

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The Internet of Things (IOT) is a technological revolution that represents the future of computing and communications. IOT is the convergence of Internet with RFID, NFC, Sensor, and smart objects. Fog Computing is the natural platform for IOT. At present, the IOT as a new network communication technology has rapidly shifted from concept to application under fog computing virtual storage computing platform. In this paper, we describe everything about IOT and difference between cloud computing and fog computing.

Keywords: cloud computing, fog computing, Internet of Things (IoT), IOT application

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295 Single-Crystal Kerfless 2D Array Transducer for Volumetric Medical Imaging: Theoretical Study

Authors: Jurij Tasinkiewicz

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The aim of this work is to present a theoretical analysis of a 2D ultrasound transducer comprised of crossed arrays of metal strips placed on both sides of thin piezoelectric layer (a). Such a structure is capable of electronic beam-steering of generated wave beam both in elevation and azimuth. In this paper, a semi-analytical model of the considered transducer is developed. It is based on generalization of the well-known BIS-expansion method. Specifically, applying the electrostatic approximation, the electric field components on the surface of the layer are expanded into fast converging series of double periodic spatial harmonics with corresponding amplitudes represented by the properly chosen Legendre polynomials. The problem is reduced to numerical solving of certain system of linear equations for unknown expansion coefficients.

Keywords: beamforming, transducer array, BIS-expansion, piezoelectric layer

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294 Graph Similarity: Algebraic Model and Its Application to Nonuniform Signal Processing

Authors: Nileshkumar Vishnav, Aditya Tatu

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A recent approach of representing graph signals and graph filters as polynomials is useful for graph signal processing. In this approach, the adjacency matrix plays pivotal role; instead of the more common approach involving graph-Laplacian. In this work, we follow the adjacency matrix based approach and corresponding algebraic signal model. We further expand the theory and introduce the concept of similarity of two graphs. The similarity of graphs is useful in that key properties (such as filter-response, algebra related to graph) get transferred from one graph to another. We demonstrate potential applications of the relation between two similar graphs, such as nonuniform filter design, DTMF detection and signal reconstruction.

Keywords: graph signal processing, algebraic signal processing, graph similarity, isospectral graphs, nonuniform signal processing

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293 Numerical Approach for Solving the Hyper Singular Integral Equation in the Analysis of a Central Symmetrical Crack within an Infinite Strip

Authors: Ikram Slamani, Hicheme Ferdjani

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This study focuses on analyzing a Griffith crack situated at the center of an infinite strip. The problem is reformulated as a hyper-singular integral equation and solved numerically using second-order Chebyshev polynomials. The primary objective is to calculate the stress intensity factor in mode 1, denoted as K1. The obtained results reveal the influence of the strip width and crack length on the stress intensity factor, assuming stress-free edges. Additionally, a comparison is made with relevant literature to validate the findings.

Keywords: center crack, Chebyshev polynomial, hyper singular integral equation, Griffith, infinite strip, stress intensity factor

Procedia PDF Downloads 144
292 Arabic Character Recognition Using Regression Curves with the Expectation Maximization Algorithm

Authors: Abdullah A. AlShaher

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In this paper, we demonstrate how regression curves can be used to recognize 2D non-rigid handwritten shapes. Each shape is represented by a set of non-overlapping uniformly distributed landmarks. The underlying models utilize 2nd order of polynomials to model shapes within a training set. To estimate the regression models, we need to extract the required coefficients which describe the variations for a set of shape class. Hence, a least square method is used to estimate such modes. We then proceed by training these coefficients using the apparatus Expectation Maximization algorithm. Recognition is carried out by finding the least error landmarks displacement with respect to the model curves. Handwritten isolated Arabic characters are used to evaluate our approach.

Keywords: character recognition, regression curves, handwritten Arabic letters, expectation maximization algorithm

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291 Rogue Waves Arising on the Standing Periodic Wave in the High-Order Ablowitz-Ladik Equation

Authors: Yanpei Zhen

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The nonlinear Schrödinger (NLS) equation models wave dynamics in many physical problems related to fluids, plasmas, and optics. The standing periodic waves are known to be modulationally unstable, and rogue waves (localized perturbations in space and time) have been observed on their backgrounds in numerical experiments. The exact solutions for rogue waves arising on the periodic standing waves have been obtained analytically. It is natural to ask if the rogue waves persist on the standing periodic waves in the integrable discretizations of the integrable NLS equation. We study the standing periodic waves in the semidiscrete integrable system modeled by the high-order Ablowitz-Ladik (AL) equation. The standing periodic wave of the high-order AL equation is expressed by the Jacobi cnoidal elliptic function. The exact solutions are obtained by using the separation of variables and one-fold Darboux transformation. Since the cnoidal wave is modulationally unstable, the rogue waves are generated on the periodic background.

Keywords: Darboux transformation, periodic wave, Rogue wave, separating the variables

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290 Visualization of PM₂.₅ Time Series and Correlation Analysis of Cities in Bangladesh

Authors: Asif Zaman, Moinul Islam Zaber, Amin Ahsan Ali

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In recent years of industrialization, the South Asian countries are being affected by air pollution due to a severe increase in fine particulate matter 2.5 (PM₂.₅). Among them, Bangladesh is one of the most polluting countries. In this paper, statistical analyses were conducted on the time series of PM₂.₅ from various districts in Bangladesh, mostly around Dhaka city. Research has been conducted on the dynamic interactions and relationships between PM₂.₅ concentrations in different zones. The study is conducted toward understanding the characteristics of PM₂.₅, such as spatial-temporal characterization, correlation of other contributors behind air pollution such as human activities, driving factors and environmental casualties. Clustering on the data gave an insight on the districts groups based on their AQI frequency as representative districts. Seasonality analysis on hourly and monthly frequency found higher concentration of fine particles in nighttime and winter season, respectively. Cross correlation analysis discovered a phenomenon of correlations among cities based on time-lagged series of air particle readings and visualization framework is developed for observing interaction in PM₂.₅ concentrations between cities. Significant time-lagged correlations were discovered between the PM₂.₅ time series in different city groups throughout the country by cross correlation analysis. Additionally, seasonal heatmaps depict that the pooled series correlations are less significant in warmer months, and among cities of greater geographic distance as well as time lag magnitude and direction of the best shifted correlated particulate matter time series among districts change seasonally. The geographic map visualization demonstrates spatial behaviour of air pollution among districts around Dhaka city and the significant effect of wind direction as the vital actor on correlated shifted time series. The visualization framework has multipurpose usage from gathering insight of general and seasonal air quality of Bangladesh to determining the pathway of regional transportation of air pollution.

Keywords: air quality, particles, cross correlation, seasonality

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289 Spatial Interpolation Technique for the Optimisation of Geometric Programming Problems

Authors: Debjani Chakraborty, Abhijit Chatterjee, Aishwaryaprajna

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Posynomials, a special type of polynomials, having singularities, pose difficulties while solving geometric programming problems. In this paper, a methodology has been proposed and used to obtain extreme values for geometric programming problems by nth degree polynomial interpolation technique. Here the main idea to optimise the posynomial is to fit a best polynomial which has continuous gradient values throughout the range of the function. The approximating polynomial is smoothened to remove the discontinuities present in the feasible region and the objective function. This spatial interpolation method is capable to optimise univariate and multivariate geometric programming problems. An example is solved to explain the robustness of the methodology by considering a bivariate nonlinear geometric programming problem. This method is also applicable for signomial programming problem.

Keywords: geometric programming problem, multivariate optimisation technique, posynomial, spatial interpolation

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288 3D Object Model Reconstruction Based on Polywogs Wavelet Network Parametrization

Authors: Mohamed Othmani, Yassine Khlifi

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This paper presents a technique for compact three dimensional (3D) object model reconstruction using wavelet networks. It consists to transform an input surface vertices into signals,and uses wavelet network parameters for signal approximations. To prove this, we use a wavelet network architecture founded on several mother wavelet families. POLYnomials WindOwed with Gaussians (POLYWOG) wavelet families are used to maximize the probability to select the best wavelets which ensure the good generalization of the network. To achieve a better reconstruction, the network is trained several iterations to optimize the wavelet network parameters until the error criterion is small enough. Experimental results will shown that our proposed technique can effectively reconstruct an irregular 3D object models when using the optimized wavelet network parameters. We will prove that an accurateness reconstruction depends on the best choice of the mother wavelets.

Keywords: 3d object, optimization, parametrization, polywog wavelets, reconstruction, wavelet networks

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287 Bivariate Generalization of q-α-Bernstein Polynomials

Authors: Tarul Garg, P. N. Agrawal

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We propose to define the q-analogue of the α-Bernstein Kantorovich operators and then introduce the q-bivariate generalization of these operators to study the approximation of functions of two variables. We obtain the rate of convergence of these bivariate operators by means of the total modulus of continuity, partial modulus of continuity and the Peetre’s K-functional for continuous functions. Further, in order to study the approximation of functions of two variables in a space bigger than the space of continuous functions, i.e. Bögel space; the GBS (Generalized Boolean Sum) of the q-bivariate operators is considered and degree of approximation is discussed for the Bögel continuous and Bögel differentiable functions with the aid of the Lipschitz class and the mixed modulus of smoothness.

Keywords: Bögel continuous, Bögel differentiable, generalized Boolean sum, K-functional, mixed modulus of smoothness

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286 Optimal Investment and Consumption Decision for an Investor with Ornstein-Uhlenbeck Stochastic Interest Rate Model through Utility Maximization

Authors: Silas A. Ihedioha

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In this work; it is considered that an investor’s portfolio is comprised of two assets; a risky stock which price process is driven by the geometric Brownian motion and a risk-free asset with Ornstein-Uhlenbeck Stochastic interest rate of return, where consumption, taxes, transaction costs and dividends are involved. This paper aimed at the optimization of the investor’s expected utility of consumption and terminal return on his investment at the terminal time having power utility preference. Using dynamic optimization procedure of maximum principle, a second order nonlinear partial differential equation (PDE) (the Hamilton-Jacobi-Bellman equation HJB) was obtained from which an ordinary differential equation (ODE) obtained via elimination of variables. The solution to the ODE gave the closed form solution of the investor’s problem. It was found the optimal investment in the risky asset is horizon dependent and a ratio of the total amount available for investment and the relative risk aversion coefficient.

Keywords: optimal, investment, Ornstein-Uhlenbeck, utility maximization, stochastic interest rate, maximum principle

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285 Numerical Solving Method for Specific Dynamic Performance of Unstable Flight Dynamics with PD Attitude Control

Authors: M. W. Sun, Y. Zhang, L. M. Zhang, Z. H. Wang, Z. Q. Chen

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In the realm of flight control, the Proportional- Derivative (PD) control is still widely used for the attitude control in practice, particularly for the pitch control, and the attitude dynamics using PD controller should be investigated deeply. According to the empirical knowledge about the unstable flight dynamics, the control parameter combination conditions to generate sole or finite number of closed-loop oscillations, which is a quite smooth response and is more preferred by practitioners, are presented in analytical or numerical manners. To analyze the effects of the combination conditions of the control parameters, the roots of several polynomials are sought to obtain feasible solutions. These conditions can also be plotted in a 2-D plane which makes the conditions be more explicit by using multiple interval operations. Finally, numerical examples are used to validate the proposed methods and some comparisons are also performed.

Keywords: attitude control, dynamic performance, numerical solving method, interval, unstable flight dynamics

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284 A Contribution to the Polynomial Eigen Problem

Authors: Malika Yaici, Kamel Hariche, Tim Clarke

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The relationship between eigenstructure (eigenvalues and eigenvectors) and latent structure (latent roots and latent vectors) is established. In control theory eigenstructure is associated with the state space description of a dynamic multi-variable system and a latent structure is associated with its matrix fraction description. Beginning with block controller and block observer state space forms and moving on to any general state space form, we develop the identities that relate eigenvectors and latent vectors in either direction. Numerical examples illustrate this result. A brief discussion of the potential of these identities in linear control system design follows. Additionally, we present a consequent result: a quick and easy method to solve the polynomial eigenvalue problem for regular matrix polynomials.

Keywords: eigenvalues/eigenvectors, latent values/vectors, matrix fraction description, state space description

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283 A Stochastic Volatility Model for Optimal Market-Making

Authors: Zubier Arfan, Paul Johnson

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The electronification of financial markets and the rise of algorithmic trading has sparked a lot of interest from the mathematical community, for the market making-problem in particular. The research presented in this short paper solves the classic stochastic control problem in order to derive the strategy for a market-maker. It also shows how to calibrate and simulate the strategy with real limit order book data for back-testing. The ambiguity of limit-order priority in back-testing is dealt with by considering optimistic and pessimistic priority scenarios. The model, although it does outperform a naive strategy, assumes constant volatility, therefore, is not best suited to the LOB data. The Heston model is introduced to describe the price and variance process of the asset. The Trader's constant absolute risk aversion utility function is optimised by numerically solving a 3-dimensional Hamilton-Jacobi-Bellman partial differential equation to find the optimal limit order quotes. The results show that the stochastic volatility market-making model is more suitable for a risk-averse trader and is also less sensitive to calibration error than the constant volatility model.

Keywords: market-making, market-microsctrucure, stochastic volatility, quantitative trading

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282 Numerical Solution of Two-Dimensional Solute Transport System Using Operational Matrices

Authors: Shubham Jaiswal

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In this study, the numerical solution of two-dimensional solute transport system in a homogeneous porous medium of finite-length is obtained. The considered transport system have the terms accounting for advection, dispersion and first-order decay with first-type boundary conditions. Initially, the aquifer is considered solute free and a constant input-concentration is considered at inlet boundary. The solution is describing the solute concentration in rectangular inflow-region of the homogeneous porous media. The numerical solution is derived using a powerful method viz., spectral collocation method. The numerical computation and graphical presentations exhibit that the method is effective and reliable during solution of the physical model with complicated boundary conditions even in the presence of reaction term.

Keywords: two-dimensional solute transport system, spectral collocation method, Chebyshev polynomials, Chebyshev differentiation matrix

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281 Identifying the Effects of the COVID-19 Pandemic on Syrian and Congolese Refugees’ Health and Economic Access in Central Pennsylvania

Authors: Mariam Shalaby, Kayla Krause, Raisha Ismail, Daniel George

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Introduction: The Pennsylvania State College of Medicine Refugee Initiative is a student-run organization that works with eleven Syrian and Congolese refugee families. Since 2016, it has used grant funding to make weekly produce purchases at a local market, provide tutoring services, and develop trusting relationships. This case study explains how the Refugee Initiative shifted focus to face new challenges due to the COVID-19 pandemic in 2020. Methodology: When refugees who had previously attained stability found themselves unable to pay the bills, the organization shifted focus from food security to direct assistance such as applying for unemployment compensation since many had recently lost jobs. When refugee families additionally struggled to access hygiene supplies, funding was redirected to purchase them. Funds were also raised from the community to provide financial relief from unpaid rent and bills. Findings: Systemic challenges were encountered in navigating federal/state unemployment and social welfare systems, and there was a conspicuous absence of affordable, language-accessible assistance that could help refugees. Finally, as struggling public schools failed to maintain adequate English as a Second Language (ESL) education, the group’s tutoring services were hindered by social distancing and inconsistent access to distance-learning platforms. Conclusion: Ultimately, the pandemic highlighted that a charity-based arrangement is helpful but not sustainable, and challenges persist for refugee families. Based on the Refugee Initiative's experiences over the past year of the COVID-19 pandemic, several needs must be addressed to aid refugee families at this time, including: increased access to affordable and language-accessible social services, educational resources, and simpler options for grant-based financial assistance. Interventions to increase these resources will aid refugee families in need in Central Pennsylvania and internationally

Keywords: COVID-19, health, pandemic, refugees

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280 Alterations in Habitation and Architectural Education Due to the COVID-19 Pandemic: The Operation of the Architectural Studio as a Crossroad

Authors: Chrysi K. Nikoloutsou, Gianna Th. Siapati

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The pandemic limitations have altered architectural education as the discourse shifted towards virtual studios and blended learning. In addition, lockdown conditions and remote working have affected habitation. Adaptability is now a key factor. The architectural studio needs to adjust to these new terms both in education and in inhabitation. This paper will investigate the operation of an architectural studio in relation to how one experiences their house due to the pandemic, based on a literature review and qualitative research methods (interviews & workshops with students). Zenetos’ prophetic ideas of ‘Electronic Urbanism’ and ‘tele-activities’ are now more present than ever.

Keywords: architectural education, pandemic, residential design, studio pedagogy

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279 An Efficient Algorithm of Time Step Control for Error Correction Method

Authors: Youngji Lee, Yonghyeon Jeon, Sunyoung Bu, Philsu Kim

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The aim of this paper is to construct an algorithm of time step control for the error correction method most recently developed by one of the authors for solving stiff initial value problems. It is achieved with the generalized Chebyshev polynomial and the corresponding error correction method. The main idea of the proposed scheme is in the usage of the duplicated node points in the generalized Chebyshev polynomials of two different degrees by adding necessary sample points instead of re-sampling all points. At each integration step, the proposed method is comprised of two equations for the solution and the error, respectively. The constructed algorithm controls both the error and the time step size simultaneously and possesses a good performance in the computational cost compared to the original method. Two stiff problems are numerically solved to assess the effectiveness of the proposed scheme.

Keywords: stiff initial value problem, error correction method, generalized Chebyshev polynomial, node points

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278 Synthesis and Characterisation of Bi-Substituted Magnetite Nanoparticles by Mechanochemical Processing (MCP)

Authors: Morteza Mohri Esfahani, Amir S. H. Rozatian, Morteza Mozaffari

Abstract:

Single phase magnetite nanoparticles and Bi-substituted ones were prepared by mechanochemical processing (MCP). The effects of Bi-substitution on the structural and magnetic properties of the nanoparticles were studied by X-ray Diffraction (XRD) and magnetometry techniques, respectively. The XRD results showed that all samples have spinel phase and by increasing Bi content, the main diffraction peaks were shifted to higher angles, which means the lattice parameter decreases from 0.843 to 0.838 nm and then increases to 0.841 nm. Also, the results revealed that increasing Bi content lead to a decrease in saturation magnetization (Ms) from 74.9 to 48.8 emu/g and an increase in coercivity (Hc) from 96.8 to 137.1 Oe.

Keywords: bi-substituted magnetite nanoparticles, mechanochemical processing, X-ray diffraction, magnetism

Procedia PDF Downloads 535
277 Limits of Phase Modulated Frequency Shifted Holographic Vibrometry at Low Amplitudes of Vibrations

Authors: Pavel Psota, Vít Lédl, Jan Václavík, Roman Doleček, Pavel Mokrý, Petr Vojtíšek

Abstract:

This paper presents advanced time average digital holography by means of frequency shift and phase modulation. This technique can measure amplitudes of vibrations at ultimate dynamic range while the amplitude distribution evaluation is done independently in every pixel. The main focus of the paper is to gain insight into behavior of the method at low amplitudes of vibrations. In order to reach that, a set of experiments was performed. Results of the experiments together with novel noise suppression show the limit of the method to be below 0.1 nm.

Keywords: acusto-optical modulator, digital holography, low amplitudes, vibrometry

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276 Structural Element Vibration Analysis with finite element method: Use of Rayleigh Quotient

Authors: Houari Boumediene University of Science, Technology.

Abstract:

"Various methods are typically used in the dynamic analysis of transversely vibrating beams. To achieve this, numerical methods are used to solve the general eigenvalue problem. The equations of equilibrium, which describe the motion, are derived from a fourth-order differential equation. Our study is based on the finite element method, and the results of the investigation are the vibration frequencies obtained using the Jacobi method. Two types of elementary mass matrices are considered: one representing a uniform distribution of mass along the element and the other consisting of concentrated masses located at fixed points whose number increases progressively with equal distances at each evaluation stage. The beams studied have different boundary constraints, representing several classical situations. Comparisons are made for beams where the distributed mass is replaced by n concentrated masses. As expected, the first calculation stage involves determining the lowest number of beam parts that gives a frequency comparable to that obtained from the Rayleigh formula. The obtained values are then compared to theoretical results based on the assumptions of the Bernoulli-Euler theory. These steps are repeated for the second type of mass representation in the same manner."

Keywords: finite element method, bernouilli eulertheory, structural analysis, vibration analysis, rayleigh quotient

Procedia PDF Downloads 92