Search results for: five factor model of personality
18608 Numerical Simulation of Air Flow, Exhaust and Their Mixture in a Helicopter Exhaust Injective Cooler
Authors: Mateusz Paszko, Konrad Pietrykowski, Krzysztof Skiba
Abstract:
Due to low-altitude and relatively low flight speed, today’s combat assets like missile weapons equipped with infrared guidance systems are one of the most important threats to the helicopters performing combat missions. Especially meaningful in helicopter aviation is infrared emission by exhaust gases, regressed to the surroundings. Due to high temperature, exhaust gases are a major factor in detectability of a helicopter performing air combat operations. This study presents the results of simulating the flow of the mixture of exhaust and air in the flow duct of an injective exhaust cooler, adapted to cooperate with the PZL 10W turbine engine. The simulation was performed using a numerical model and the ANSYS Fluent software. Simulation computations were conducted for set flight conditions of the PZL W-3 Falcon helicopter. The conclusions resulting from the conducted numerical computations should allow for optimisation of the flow duct geometry in the cooler, in order to achieve the greatest possible temperature reduction of exhaust exiting into the surroundings. It is expected that the obtained results should be useful for further works related to the development of the final version of exhaust cooler for the PZL W-3 Falcon helicopter.Keywords: exhaust cooler, helicopter, numerical simulation, stealth
Procedia PDF Downloads 15318607 Prediction of Solidification Behavior of Al Alloy in a Cube Mold Cavity
Authors: N. P. Yadav, Deepti Verma
Abstract:
This paper focuses on the mathematical modeling for solidification of Al alloy in a cube mould cavity to study the solidification behavior of casting process. The parametric investigation of solidification process inside the cavity was performed by using computational solidification/melting model coupled with Volume of fluid (VOF) model. The implicit filling algorithm is used in this study to understand the overall process from the filling stage to solidification in a model metal casting process. The model is validated with past studied at same conditions. The solidification process are analyzed by including the effect of pouring velocity and temperature of liquid metal, effect of wall temperature as well natural convection from the wall and geometry of the cavity. These studies show the possibility of various defects during solidification process.Keywords: buoyancy driven flow, natural convection driven flow, residual flow, secondary flow, volume of fluid
Procedia PDF Downloads 42118606 Fault Prognostic and Prediction Based on the Importance Degree of Test Point
Authors: Junfeng Yan, Wenkui Hou
Abstract:
Prognostics and Health Management (PHM) is a technology to monitor the equipment status and predict impending faults. It is used to predict the potential fault and provide fault information and track trends of system degradation by capturing characteristics signals. So how to detect characteristics signals is very important. The select of test point plays a very important role in detecting characteristics signal. Traditionally, we use dependency model to select the test point containing the most detecting information. But, facing the large complicated system, the dependency model is not built so easily sometimes and the greater trouble is how to calculate the matrix. Rely on this premise, the paper provide a highly effective method to select test point without dependency model. Because signal flow model is a diagnosis model based on failure mode, which focuses on system’s failure mode and the dependency relationship between the test points and faults. In the signal flow model, a fault information can flow from the beginning to the end. According to the signal flow model, we can find out location and structure information of every test point and module. We break the signal flow model up into serial and parallel parts to obtain the final relationship function between the system’s testability or prediction metrics and test points. Further, through the partial derivatives operation, we can obtain every test point’s importance degree in determining the testability metrics, such as undetected rate, false alarm rate, untrusted rate. This contributes to installing the test point according to the real requirement and also provides a solid foundation for the Prognostics and Health Management. According to the real effect of the practical engineering application, the method is very efficient.Keywords: false alarm rate, importance degree, signal flow model, undetected rate, untrusted rate
Procedia PDF Downloads 38318605 Bifurcation and Chaos of the Memristor Circuit
Authors: Wang Zhulin, Min Fuhong, Peng Guangya, Wang Yaoda, Cao Yi
Abstract:
In this paper, a magnetron memristor model based on hyperbolic sine function is presented and the correctness proved by studying the trajectory of its voltage and current phase, and then a memristor chaotic system with the memristor model is presented. The phase trajectories and the bifurcation diagrams and Lyapunov exponent spectrum of the magnetron memristor system are plotted by numerical simulation, and the chaotic evolution with changing the parameters of the system is also given. The paper includes numerical simulations and mathematical model, which confirming that the system, has a wealth of dynamic behavior.Keywords: memristor, chaotic circuit, dynamical behavior, chaotic system
Procedia PDF Downloads 50718604 A Machine Learning Model for Predicting Students’ Academic Performance in Higher Institutions
Authors: Emmanuel Osaze Oshoiribhor, Adetokunbo MacGregor John-Otumu
Abstract:
There has been a need in recent years to predict student academic achievement prior to graduation. This is to assist them in improving their grades, especially for those who have struggled in the past. The purpose of this research is to use supervised learning techniques to create a model that predicts student academic progress. Many scholars have developed models that predict student academic achievement based on characteristics including smoking, demography, culture, social media, parent educational background, parent finances, and family background, to mention a few. This element, as well as the model used, could have misclassified the kids in terms of their academic achievement. As a prerequisite to predicting if the student will perform well in the future on related courses, this model is built using a logistic regression classifier with basic features such as the previous semester's course score, attendance to class, class participation, and the total number of course materials or resources the student is able to cover per semester. With a 96.7 percent accuracy, the model outperformed other classifiers such as Naive bayes, Support vector machine (SVM), Decision Tree, Random forest, and Adaboost. This model is offered as a desktop application with user-friendly interfaces for forecasting student academic progress for both teachers and students. As a result, both students and professors are encouraged to use this technique to predict outcomes better.Keywords: artificial intelligence, ML, logistic regression, performance, prediction
Procedia PDF Downloads 11318603 Modelling and Optimization Analysis of Silicon/MgZnO-CBTSSe Tandem Solar Cells
Authors: Vallisree Sivathanu, Kumaraswamidhas Lakshmi Annamalai, Trupti Ranjan Lenka
Abstract:
We report a tandem solar cell model with Silicon as the bottom cell absorber material and Cu₂BaSn(S, Se)₄(CBTSSe) as absorber material for the top cell. As a first step, the top and bottom cells were modelled and validated by comparison with the experiment. Once the individual cells are validated, then the tandem structure is modelled with Indium Tin Oxide(ITO) as conducting layer between the top and bottom cells. The tandem structure yielded better open circuit voltage and fill factor; however, the efficiency obtained is 7.01%. The top cell and the bottom cells are investigated with the help of electron-hole current density, photogeneration rate, and external quantum efficiency profiles. In order to minimize the various loss mechanisms in the tandem solar cell, the material parameters are optimized within experimentally achievable limits. Initially, the top cell optimization was carried out; then, the bottom cell is optimized for maximizing the light absorption, and upon minimizing the current and photon losses in the tandem structure, the maximum achievable efficiency is predicted to be 19.52%.Keywords: CBTSSe, silicon, tandem, solar cell, device modeling, current losses, photon losses
Procedia PDF Downloads 12218602 Multistage Data Envelopment Analysis Model for Malmquist Productivity Index Using Grey's System Theory to Evaluate Performance of Electric Power Supply Chain in Iran
Authors: Mesbaholdin Salami, Farzad Movahedi Sobhani, Mohammad Sadegh Ghazizadeh
Abstract:
Evaluation of organizational performance is among the most important measures that help organizations and entities continuously improve their efficiency. Organizations can use the existing data and results from the comparison of units under investigation to obtain an estimation of their performance. The Malmquist Productivity Index (MPI) is an important index in the evaluation of overall productivity, which considers technological developments and technical efficiency at the same time. This article proposed a model based on the multistage MPI, considering limited data (Grey’s theory). This model can evaluate the performance of units using limited and uncertain data in a multistage process. It was applied by the electricity market manager to Iran’s electric power supply chain (EPSC), which contains uncertain data, to evaluate the performance of its actors. Results from solving the model showed an improvement in the accuracy of future performance of the units under investigation, using the Grey’s system theory. This model can be used in all case studies, in which MPI is used and there are limited or uncertain data.Keywords: Malmquist Index, Grey's Theory, CCR Model, network data envelopment analysis, Iran electricity power chain
Procedia PDF Downloads 16918601 Geometric Contrast of a 3D Model Obtained by Means of Digital Photogrametry with a Quasimetric Camera on UAV Classical Methods
Authors: Julio Manuel de Luis Ruiz, Javier Sedano Cibrián, Rubén Pérez Álvarez, Raúl Pereda García, Cristina Diego Soroa
Abstract:
Nowadays, the use of drones has been extended to practically any human activity. One of the main applications is focused on the surveying field. In this regard, software programs that process the images captured by the sensor from the drone in an almost automatic way have been developed and commercialized, but they only allow contrasting the results through control points. This work proposes the contrast of a 3D model obtained from a flight developed by a drone and a non-metric camera (due to its low cost), with a second model that is obtained by means of the historically-endorsed classical methods. In addition to this, the contrast is developed over a certain territory with a significant unevenness, so as to test the model generated with photogrammetry, and considering that photogrammetry with drones finds more difficulties in terms of accuracy in this kind of situations. Distances, heights, surfaces and volumes are measured on the basis of the 3D models generated, and the results are contrasted. The differences are about 0.2% for the measurement of distances and heights, 0.3% for surfaces and 0.6% when measuring volumes. Although they are not important, they do not meet the order of magnitude that is presented by salespeople.Keywords: accuracy, classical topographic, model tridimensional, photogrammetry, Uav.
Procedia PDF Downloads 14118600 Influence of Silica Fume Addition on Concrete
Authors: Gaurav Datta, Sourav Ghosh, Rahul Roy
Abstract:
The incorporation of silica fume into the normal concrete is a routine one in the present days to produce the tailor made high strength and high performance concrete. The design parameters are increasing with the incorporation of silica fume in conventional concrete and the mix proportioning is becoming complex. The main objective of this paper has been made to investigate the different mechanical properties like compressive strength, permeability, porosity, density, modulus of elasticity, compacting factor, slump of concrete incorporating silica fume. In this present paper 5 (five) mix of concrete incorporating silica fume is cast to perform experiments. These experiments were carried out by replacing cement with different percentages of silica fume at a single constant water-cementitious materials ratio keeping other mix design variables constant. The silica fume was replaced by 0%, 5%, 10%, 15% and 20% for water-cementitious materials (w/cm) ratio for 0.40. For all mixes compressive strengths were determined at 24 hours, 7 and 28 days for 100 mm and 150 mm cubes. Other properties like permeability, porosity, density, modulus of elasticity, compacting factor, and slump were also determined for five mixes of concrete.Keywords: high performance concrete, high strength concrete, silica fume, strength
Procedia PDF Downloads 29518599 Impulsivity and Nutritional Restrictions in BED
Authors: Jaworski Mariusz, Owczarek Krzysztof, Adamus Mirosława
Abstract:
Binge eating disorder (BED) is one of the three main eating disorders, beside anorexia and bulimia nervosa. BED is characterized by a loss of control over the quantity of food consumed and the lack of the compensatory behaviors, such as induced vomiting or purging. Studies highlight that certain personality traits may contribute to the severity of symptoms in the ED. The aim of this study is to analyze the relationship between psychological variables (Impulsivity and Urgency) and Nutritional restrictions in BED. The study included two groups. The first group consisted of 35 women with BED aged 18 to 28. The control group - 35 women without ED aged 18 to 28. ED-1 questionnaire was used in a study to assess the severity of impulsivity, urgency and nutritional restrictions. The obtained data were standardized. Statistical analyzes were performed using SPSS 21 software. The severity of impulsivity was higher in patients with BED than the control group. The relation between impulsivity and nutritional restrictions in BED was observed, only taking into consideration the relationship of these variables with the level of urgency. However, if the severity of urgency in this relationship is skipped, the relationship between impulsivity and nutritional restrictions will not occur. Impulsivity has a negative relationship with the level of urgency. This study suggests the need to analyze the interaction between impulsivity and urgency, and their relationship with dietary behavior in BED, especially nutritional restrictions. Analysis of single isolated features may give erroneous results.Keywords: binge eating disorder, impulsivity, nutritional restrictions, urgency
Procedia PDF Downloads 47418598 Building Information Management in Context of Urban Spaces, Analysis of Current Use and Possibilities
Authors: Lucie Jirotková, Daniel Macek, Andrea Palazzo, Veronika Malinová
Abstract:
Currently, the implementation of 3D models in the construction industry is gaining popularity. Countries around the world are developing their own modelling standards and implement the use of 3D models into their individual permitting processes. Another theme that needs to be addressed are public building spaces and their subsequent maintenance, where the usage of BIM methodology is directly offered. The significant benefit of the implementation of Building Information Management is the information transfer. The 3D model contains not only the spatial representation of the item shapes but also various parameters that are assigned to the individual elements, which are easily traceable, mainly because they are all stored in one place in the BIM model. However, it is important to keep the data in the models up to date to achieve useability of the model throughout the life cycle of the building. It is now becoming standard practice to use BIM models in the construction of buildings, however, the building environment is very often neglected. Especially in large-scale development projects, the public space of buildings is often forwarded to municipalities, which obtains the ownership and are in charge of its maintenance. A 3D model of the building surroundings would include both the above-ground visible elements of the development as well as the underground parts, such as the technological facilities of water features, electricity lines for public lighting, etc. The paper shows the possibilities of a model in the field of information for the handover of premises, the following maintenance and decision making. The attributes and spatial representation of the individual elements make the model a reliable foundation for the creation of "Smart Cities". The paper analyses the current use of the BIM methodology and presents the state-of-the-art possibilities of development.Keywords: BIM model, urban space, BIM methodology, facility management
Procedia PDF Downloads 12718597 Computational Fluid Dynamicsfd Simulations of Air Pollutant Dispersion: Validation of Fire Dynamic Simulator Against the Cute Experiments of the Cost ES1006 Action
Authors: Virginie Hergault, Siham Chebbah, Bertrand Frere
Abstract:
Following in-house objectives, Central laboratory of Paris police Prefecture conducted a general review on models and Computational Fluid Dynamics (CFD) codes used to simulate pollutant dispersion in the atmosphere. Starting from that review and considering main features of Large Eddy Simulation, Central Laboratory Of Paris Police Prefecture (LCPP) postulates that the Fire Dynamics Simulator (FDS) model, from National Institute of Standards and Technology (NIST), should be well suited for air pollutant dispersion modeling. This paper focuses on the implementation and the evaluation of FDS in the frame of the European COST ES1006 Action. This action aimed at quantifying the performance of modeling approaches. In this paper, the CUTE dataset carried out in the city of Hamburg, and its mock-up has been used. We have performed a comparison of FDS results with wind tunnel measurements from CUTE trials on the one hand, and, on the other, with the models results involved in the COST Action. The most time-consuming part of creating input data for simulations is the transfer of obstacle geometry information to the format required by SDS. Thus, we have developed Python codes to convert automatically building and topographic data to the FDS input file. In order to evaluate the predictions of FDS with observations, statistical performance measures have been used. These metrics include the fractional bias (FB), the normalized mean square error (NMSE) and the fraction of predictions within a factor of two of observations (FAC2). As well as the CFD models tested in the COST Action, FDS results demonstrate a good agreement with measured concentrations. Furthermore, the metrics assessment indicate that FB and NMSE meet the tolerance acceptable.Keywords: numerical simulations, atmospheric dispersion, cost ES1006 action, CFD model, cute experiments, wind tunnel data, numerical results
Procedia PDF Downloads 14018596 A Frictional-Collisional Closure Model for the Saturated Granular Flow: Experimental Evidence and Two Phase Modelling
Authors: Yunhui Sun, Qingquan Liu, Xiaoliang Wang
Abstract:
Dense granular flows widely exist in geological flows such as debris flow, landslide, or sheet flow, where both the interparticle and solid-liquid interactions are important to modify the flow. So, a two-phase approach with both phases correctly modelled is important for a better investigation of the saturated granular flows. However, a proper closure model covering a wide range of flowing states for the solid phase is still lacking. This study first employs a chute flow experiment based on the refractive index matching method, which makes it possible to obtain internal flow information such as velocity, shear rate, granular fluctuation, and volume fraction. The granular stress is obtained based on a steady assumption. The kinetic theory is found to describe the stress dependence on the flow state well. More importantly, the granular rheology is found to be frictionally dominated under weak shear and collisionally dominated under strong shear. The results presented thus provide direct experimental evidence on a possible frictional-collisional closure model for the granular phase. The data indicates that both frictional stresses exist over a wide range of the volume fraction, though traditional theory believes it vanishes below a critical volume fraction. Based on the findings, a two-phase model is used to simulate the chute flow. Both phases are modelled as continuum media, and the inter-phase interactions, such as drag force and pressure gradient force, are considered. The frictional-collisional model is used for the closure of the solid phase stress. The profiles of the kinematic properties agree well with the experiments. This model is further used to simulate immersed granular collapse, which is unsteady in nature, to study the applicability of this model, which is derived from steady flow.Keywords: closure model, collision, friction, granular flow, two-phase model
Procedia PDF Downloads 6318595 Time Series Modelling and Prediction of River Runoff: Case Study of Karkheh River, Iran
Authors: Karim Hamidi Machekposhti, Hossein Sedghi, Abdolrasoul Telvari, Hossein Babazadeh
Abstract:
Rainfall and runoff phenomenon is a chaotic and complex outcome of nature which requires sophisticated modelling and simulation methods for explanation and use. Time Series modelling allows runoff data analysis and can be used as forecasting tool. In the paper attempt is made to model river runoff data and predict the future behavioural pattern of river based on annual past observations of annual river runoff. The river runoff analysis and predict are done using ARIMA model. For evaluating the efficiency of prediction to hydrological events such as rainfall, runoff and etc., we use the statistical formulae applicable. The good agreement between predicted and observation river runoff coefficient of determination (R2) display that the ARIMA (4,1,1) is the suitable model for predicting Karkheh River runoff at Iran.Keywords: time series modelling, ARIMA model, river runoff, Karkheh River, CLS method
Procedia PDF Downloads 34418594 An Empirical Study to Predict Myocardial Infarction Using K-Means and Hierarchical Clustering
Authors: Md. Minhazul Islam, Shah Ashisul Abed Nipun, Majharul Islam, Md. Abdur Rakib Rahat, Jonayet Miah, Salsavil Kayyum, Anwar Shadaab, Faiz Al Faisal
Abstract:
The target of this research is to predict Myocardial Infarction using unsupervised Machine Learning algorithms. Myocardial Infarction Prediction related to heart disease is a challenging factor faced by doctors & hospitals. In this prediction, accuracy of the heart disease plays a vital role. From this concern, the authors have analyzed on a myocardial dataset to predict myocardial infarction using some popular Machine Learning algorithms K-Means and Hierarchical Clustering. This research includes a collection of data and the classification of data using Machine Learning Algorithms. The authors collected 345 instances along with 26 attributes from different hospitals in Bangladesh. This data have been collected from patients suffering from myocardial infarction along with other symptoms. This model would be able to find and mine hidden facts from historical Myocardial Infarction cases. The aim of this study is to analyze the accuracy level to predict Myocardial Infarction by using Machine Learning techniques.Keywords: Machine Learning, K-means, Hierarchical Clustering, Myocardial Infarction, Heart Disease
Procedia PDF Downloads 20718593 A Graph SEIR Cellular Automata Based Model to Study the Spreading of a Transmittable Disease
Authors: Natasha Sharma, Kulbhushan Agnihotri
Abstract:
Cellular Automata are discrete dynamical systems which are based on local character and spatial disparateness of the spreading process. These factors are generally neglected by traditional models based on differential equations for epidemic spread. The aim of this work is to introduce an SEIR model based on cellular automata on graphs to imitate epidemic spreading. Distinctively, it is an SEIR-type model where the population is divided into susceptible, exposed, infected and recovered individuals. The results obtained from simulations are in accordance with the spreading behavior of a real time epidemics.Keywords: cellular automata, epidemic spread, graph, susceptible
Procedia PDF Downloads 46318592 H2/He and H2O/He Separation Experiments with Zeolite Membranes for Nuclear Fusion Applications
Authors: Rodrigo Antunes, Olga Borisevich, David Demange
Abstract:
In future nuclear fusion reactors, tritium self-sufficiency will be ensured by tritium (3H) production via reactions between the fusion neutrons and lithium. To favor tritium breeding, a neutron multiplier must also be used. Both tritium breeder and neutron multiplier will be placed in the so-called Breeding Blanket (BB). For the European Helium-Cooled Pebble Bed (HCPB) BB concept, the tritium production and neutron multiplication will be ensured by neutron bombardment of Li4SiO4 and Be pebbles, respectively. The produced tritium is extracted from the pebbles by purging them with large flows of He (~ 104 Nm3h-1), doped with small amounts of H2 (~ 0.1 vol%) to promote tritium extraction via isotopic exchange (producing HT). Due to the presence of oxygen in the pebbles, production of tritiated water is unavoidable. Therefore, the purging gas downstream of the BB will be composed by Q2/Q2O/He (Q = 1H, 2H, 3H), with Q2/Q2O down to ppm levels, which must be further processed for tritium recovery. A two-stage continuous approach, where zeolite membranes (ZMs) are followed by a catalytic membrane reactor (CMR), has been recently proposed to fulfil this task. The tritium recovery from Q2/Q2O/He is ensured by the CMR, that requires a reduction of the gas flow coming from the BB and a pre-concentration of Q2 and Q2O to be efficient. For this reason, and to keep this stage with reasonable dimensions, ZMs are required upfront to reduce as much as possible the He flows and concentrate the Q2/Q2O species. Therefore, experimental activities have been carried out at the Tritium Laboratory Karlsruhe (TLK) to test the separation performances of different zeolite membranes for H2/H2O/He. First experiments have been performed with binary mixtures of H2/He and H2O/He with commercial MFI-ZSM5 and NaA zeolite-type membranes. Only the MFI-ZSM5 demonstrated selectivity towards H2, with a separation factor around 1.5, and H2 permeances around 0.72 µmolm-2s-1Pa-1, rather independent for feed concentrations in the range 0.1 vol%-10 vol% H2/He. The experiments with H2O/He have demonstrated that the separation factor towards H2O is highly dependent on the feed concentration and temperature. For instance, at 0.2 vol% H2O/He the separation factor with NaA is below 2 and around 1000 at 5 vol% H2O/He, at 30°C. Overall, both membranes demonstrated complementary results at equivalent temperatures. In fact, at low feed concentrations ( ≤ 1 vol% H2O/He) MFI-ZSM5 separates better than NaA, whereas the latter has higher separation factors for higher inlet water content ( ≥ 5 vol% H2O/He). In this contribution, the results obtained with both MFI-ZSM5 and NaA membranes for H2/He and H2O/H2 mixtures at different concentrations and temperatures are compared and discussed.Keywords: nuclear fusion, gas separation, tritium processes, zeolite membranes
Procedia PDF Downloads 29018591 Understanding the Influence on Drivers’ Recommendation and Review-Writing Behavior in the P2P Taxi Service
Authors: Liwen Hou
Abstract:
The booming mobile business has been penetrating the taxi industry worldwide with P2P (peer to peer) taxi services, as an emerging business model, transforming the industry. Parallel with other mobile businesses, member recommendations and online reviews are believed to be very effective with regard to acquiring new users for P2P taxi services. Based on an empirical dataset of the taxi industry in China, this study aims to reveal which factors influence users’ recommendations and review-writing behaviors. Differing from the existing literature, this paper takes the taxi driver’s perspective into consideration and hence selects a group of variables related to the drivers. We built two models to reflect the factors that influence the number of recommendations and reviews posted on the platform (i.e., the app). Our models show that all factors, except the driver’s score, significantly influence the recommendation behavior. Likewise, only one factor, passengers’ bad reviews, is insignificant in generating more drivers’ reviews. In the conclusion, we summarize the findings and limitations of the research.Keywords: online recommendation, P2P taxi service, review-writing, word of mouth
Procedia PDF Downloads 31118590 Investigating the Dynamics of Knowledge Acquisition in Undergraduate Mathematics Students Using Differential Equations
Authors: Gilbert Makanda
Abstract:
The problem of the teaching of mathematics is studied using differential equations. A mathematical model for knowledge acquisition in mathematics is developed. In this study we adopt the mathematical model that is normally used for disease modelling in the teaching of mathematics. It is assumed that teaching is 'infecting' students with knowledge thereby spreading this knowledge to the students. It is also assumed that students who gain this knowledge spread it to other students making disease model appropriate to adopt for this problem. The results of this study show that increasing recruitment rates, learning contact with teachers and learning materials improves the number of knowledgeable students. High dropout rates and forgetting taught concepts also negatively affect the number of knowledgeable students. The developed model is then solved using Matlab ODE45 and \verb"lsqnonlin" to estimate parameters for the actual data.Keywords: differential equations, knowledge acquisition, least squares, dynamical systems
Procedia PDF Downloads 42918589 E-Bike FE Model Analysis: Connection Stiffness of Elements with Different DOFs
Authors: Lele Zhang, Hui Leng Choo, Alexander Konyukhov, Shuguang Li
Abstract:
Finite Element (FE) model of simplified e-bike structure was generated by main frame with two tiers, which consisted of pipe, mass, beam, and shell elements (pipe 289, beam188, shell 181, shell 281, combin14, link11, mass21). These elements would be introduced and demonstrated using mathematical formulas. Based on coupling theory, constrain equations was proposed. Exporting all the parameters obtained from theory part, the connection stiffness matrix of the whole e-bike structure between each of these elements was detected.Keywords: coupling theory, stiffness matrix, e-bike, finite element model
Procedia PDF Downloads 37918588 Developing a Model – an Application of Fuzzy Analytic Network Process Techniques for Hostels
Authors: Pin-Ju Juan, Peng-Yu Juan, Yi-Shan Chen
Abstract:
The main purpose of this paper is to present a fuzzy Analytic Network Process (ANP) model for the hostel organizational performance selection. In this article, we created 39 criteria for selecting hostel organizational performance acquired from literature's review and experts method practical investigations, and the methods of fuzzy analytic network process are used to consolidate decision-makers’ assessments about criteria weightings. Finally, we selected organizational performance of a hostel in Taiwan to determine the effectiveness of the proposed evaluation model in this paper.Keywords: Fuzzy ANP, hostel, organizational performance, strategy management
Procedia PDF Downloads 20518587 Modeling of Masonry In-Filled R/C Frame to Evaluate Seismic Performance of Existing Building
Authors: Tarek M. Alguhane, Ayman H. Khalil, M. N. Fayed, Ayman M. Ismail
Abstract:
This paper deals with different modeling aspects of masonry infill: no infill model, Layered shell infill model, and strut infill model. These models consider the complicated behavior of the in-filled plane frames under lateral load similar to an earthquake load. Three strut infill models are used: NBCC (2005) strut infill model, ASCE/SEI 41-06 strut infill model and proposed strut infill model based on modification to Canadian, NBCC (2005) strut infill model. Pushover and modal analyses of a masonry infill concrete frame with a single storey and an existing 5-storey RC building have been carried out by using different models for masonry infill. The corresponding hinge status, the value of base shear at target displacement as well as their dynamic characteristics have been determined and compared. A validation of the structural numerical models for the existing 5-storey RC building has been achieved by comparing the experimentally measured and the analytically estimated natural frequencies and their mode shapes. This study shows that ASCE/SEI 41-06 equation underestimates the values for the equivalent properties of the diagonal strut while Canadian, NBCC (2005) equation gives realistic values for the equivalent properties. The results indicate that both ASCE/SEI 41-06 and Canadian, NBCC (2005) equations for strut infill model give over estimated values for dynamic characteristic of the building. Proposed modification to Canadian, NBCC (2005) equation shows that the fundamental dynamic characteristic values of the building are nearly similar to the corresponding values using layered shell elements as well as measured field results.Keywords: masonry infill, framed structures, RC buildings, non-structural elements
Procedia PDF Downloads 28018586 The Implementation of Strengthening Institutional Model of Women Farmers Group in Developing Household Food Security
Authors: Rahmadanih, Sitti Bulkis, A. Amrullah, R. M. Rukka, N. M. Viantika
Abstract:
Food security is still a global issue, including in Indonesia. In South Sulawesi, this issue also occurs in members of farmer groups/women farmer groups. This study aims to (1) describe the implementation of strengthening institutional model of Women Farmer Groups (WFG) and (2) analyzing the capacity building of WFG members in order to develop food security after the implementations on institutional model. The research was conducted in Bulukumba and Luwu Utara District, South Sulawesi, Indonesia. The research was designed with qualitative and quantitative (mixed) method. Qualitative data were collected through in-depth interview and Focus Group Discussion (FGD); while quantitative data collected through a household survey of WGF members. Two WGF were selected they are WFG in Bulukumba and WGF in Luwu Utara District. Both WGF has been selected as the case unit, which consisting of 60 households. Institutional strengthening model that been implemented is a combination model of (1) institutional support and (2) capacity development of WGF members. The model of institutional support aim is to develop food security could be achieved through facilitation on produce banana chips (initiate a business group formation) and preparation of institution rule (AD/ART). (2) The developing Model of WFG members capacity building are (a) technical training of banana chips producing process, also food and nutrition counseling as well as the utilization of the yard, (b) processing of food products from their yards. Food and nutrition knowledge of WFG members was increased about 30% - 60% and accompanied by the development of households’ food security by 6.7% - 10.0%.; when compared to last year percentage.Keywords: food security, institutional strengthening, model implementation, women farmer group
Procedia PDF Downloads 18318585 Poverty Dynamics in Thailand: Evidence from Household Panel Data
Authors: Nattabhorn Leamcharaskul
Abstract:
This study aims to examine determining factors of the dynamics of poverty in Thailand by using panel data of 3,567 households in 2007-2017. Four techniques of estimation are employed to analyze the situation of poverty across households and time periods: the multinomial logit model, the sequential logit model, the quantile regression model, and the difference in difference model. Households are categorized based on their experiences into 5 groups, namely chronically poor, falling into poverty, re-entering into poverty, exiting from poverty and never poor households. Estimation results emphasize the effects of demographic and socioeconomic factors as well as unexpected events on the economic status of a household. It is found that remittances have positive impact on household’s economic status in that they are likely to lower the probability of falling into poverty or trapping in poverty while they tend to increase the probability of exiting from poverty. In addition, not only receiving a secondary source of household income can raise the probability of being a never poor household, but it also significantly increases household income per capita of the chronically poor and falling into poverty households. Public work programs are recommended as an important tool to relieve household financial burden and uncertainty and thus consequently increase a chance for households to escape from poverty.Keywords: difference in difference, dynamic, multinomial logit model, panel data, poverty, quantile regression, remittance, sequential logit model, Thailand, transfer
Procedia PDF Downloads 11818584 Exploring Male and Female Consumers’ Perceptions of Clothing Retailers’ CSR Initiatives in South Africa
Authors: Gerhard D. Muller, Nadine C. Sonnenberg, Suné Donoghue
Abstract:
This study delves into the intricacies of male and female consumers’ perceptions of Corporate Social Responsibility (CSR) in the South African clothing retail sector, a sector experiencing increasing consumption, yet facing significant environmental and social challenges. The aim is to discern between male and female consumers’ perceptions of clothing retailers’ CSR initiatives based on the Triple Bottom Line (TBL) framework, which evaluates organizational sustainability across social, environmental, and economic domains. Methodologically, the study is embedded in a quantitative research paradigm adopting a cross-sectional survey design. A purposive sampling strategy was used to recruit male and female respondents from a diverse South African demographic background. A structured questionnaire was developed and included established consumer CSR perception scales that were adapted for the purposes of this study. The questionnaire was distributed via online platforms. The data collected from the online survey, were split by gender to allow for comparison between male and female consumers’ perceptions of clothing retailers’ CSR initiatives. Exploratory Factor Analysis (EFA) was conducted on each of the datasets. The EFA for females revealed a five-factor solution, whereas the male EFA presented a six-factor solution, with the notable addition of an Economic Performance dimension. Results indicate subtle differences in the gender groups’ CSR perceptions. While both genders seem to value clothing retailers’ focus on quality services, females seem to have more pronounced perceptions surrounding clothing retailers’ contributions to social and environmental causes. Males, on the other hand, seem to be more discerning in their perceptions surrounding clothing retailers’ support of social and environmental causes. Ethical stakeholder relationships emerged as a shared concern across genders. Still, males presented a distinct factor, Economic Performance, highlighting a gendered divergence in the weighting of economic success and financial performance in CSR evaluation. The implications of these results are multifaceted. Theoretically, the study enriches the discourse on CSR by integrating gender insights into the TBL framework, offering a greater understanding of consumers’ CSR perceptions in the South African clothing retail context. Practically, it provides actionable insights for clothing retailers, suggesting that CSR initiatives should be gender-sensitive and communicate the TBL's elements effectively to resonate with the pertinent concerns of each segment. Additionally, the findings advocate for a contextualized approach to CSR in emerging markets that aligns with local cultural and social differences.Keywords: consumer perceptions, corporate Social responsibility, gender differentiation, triple bottom line
Procedia PDF Downloads 7018583 Improving Pneumatic Artificial Muscle Performance Using Surrogate Model: Roles of Operating Pressure and Tube Diameter
Authors: Van-Thanh Ho, Jaiyoung Ryu
Abstract:
In soft robotics, the optimization of fluid dynamics through pneumatic methods plays a pivotal role in enhancing operational efficiency and reducing energy loss. This is particularly crucial when replacing conventional techniques such as cable-driven electromechanical systems. The pneumatic model employed in this study represents a sophisticated framework designed to efficiently channel pressure from a high-pressure reservoir to various muscle locations on the robot's body. This intricate network involves a branching system of tubes. The study introduces a comprehensive pneumatic model, encompassing the components of a reservoir, tubes, and Pneumatically Actuated Muscles (PAM). The development of this model is rooted in the principles of shock tube theory. Notably, the study leverages experimental data to enhance the understanding of the interplay between the PAM structure and the surrounding fluid. This improved interactive approach involves the use of morphing motion, guided by a contraction function. The study's findings demonstrate a high degree of accuracy in predicting pressure distribution within the PAM. The model's predictive capabilities ensure that the error in comparison to experimental data remains below a threshold of 10%. Additionally, the research employs a machine learning model, specifically a surrogate model based on the Kriging method, to assess and quantify uncertainty factors related to the initial reservoir pressure and tube diameter. This comprehensive approach enhances our understanding of pneumatic soft robotics and its potential for improved operational efficiency.Keywords: pneumatic artificial muscles, pressure drop, morhing motion, branched network, surrogate model
Procedia PDF Downloads 10218582 Stoner Impurity Model in Nickel Hydride
Authors: Andrea Leon, J. M. Florez, P. Vargas
Abstract:
The effect of hydrogen adsorption on the magnetic properties of fcc Ni has been calculated using the linear-muffin-tin-orbital formalism and using the local-density approximation for the exchange y correlation. The calculations for the ground state show that the sequential addition of hydrogen atoms is found to monotonically reduce the total magnetic moment of the Ni fcc structure, as a result of changes in the exchange-splitting parameter and in the Fermi energy. In order to physically explain the effect of magnetization reduction as the Hydrogen concentration increases, we propose a Stoner impurity model to describe the influence of H impurity on the magnetic properties of Nickel.Keywords: electronic structure, magnetic properties, Nickel hydride, stoner model
Procedia PDF Downloads 46118581 Dynamic Model of Automatic Loom on SimulationX
Authors: A. Jomartov, A. Tuleshov, B. Tultaev
Abstract:
One of the main tasks in the development of textile machinery is to increase the rapidity of automatic looms, and consequently, their productivity. With increasing automatic loom speeds, the dynamic loads on their separate mechanisms and moving joints sharply increase. Dynamic research allows us to determine the weakest mechanisms of the automatic loom. The modern automatic loom consists of a large number of structurally different mechanisms. These are cam, lever, gear, friction and combined cyclic mechanisms. The modern automatic loom contains various mechatronic devices: A device for the automatic removal of faulty weft, electromechanical drive warp yarns, electronic controllers, servos, etc. In the paper, we consider the multibody dynamic model of the automatic loom on the software complex SimulationX. SimulationX is multidisciplinary software for modeling complex physical and technical facilities and systems. The multibody dynamic model of the automatic loom allows consideration of: The transition processes, backlash at the joints and nodes, the force of resistance and electric motor performance.Keywords: automatic loom, dynamics, model, multibody, SimulationX
Procedia PDF Downloads 35218580 Towards a Security Model against Denial of Service Attacks for SIP Traffic
Authors: Arellano Karina, Diego Avila-Pesántez, Leticia Vaca-Cárdenas, Alberto Arellano, Carmen Mantilla
Abstract:
Nowadays, security threats in Voice over IP (VoIP) systems are an essential and latent concern for people in charge of security in a corporate network, because, every day, new Denial-of-Service (DoS) attacks are developed. These affect the business continuity of an organization, regarding confidentiality, availability, and integrity of services, causing frequent losses of both information and money. The purpose of this study is to establish the necessary measures to mitigate DoS threats, which affect the availability of VoIP systems, based on the Session Initiation Protocol (SIP). A Security Model called MS-DoS-SIP is proposed, which is based on two approaches. The first one analyzes the recommendations of international security standards. The second approach takes into account weaknesses and threats. The implementation of this model in a VoIP simulated system allowed to minimize the present vulnerabilities in 92% and increase the availability time of the VoIP service into an organization.Keywords: Denial-of-Service SIP attacks, MS-DoS-SIP, security model, VoIP-SIP vulnerabilities
Procedia PDF Downloads 20518579 Application of Terminal Sliding Mode Control to the Stabilization of the Indoor Temperature in Buildings
Authors: Pawel Skruch, Marek Dlugosz
Abstract:
The paper starts with a general model of the temperature dynamics in buildings. The modelling approach relies on thermodynamics, in particular heat transfer, principles. The model considers heat loses by conduction and ventilation and internal heat gains. The parameters of the model can be determined uniquely from the geometry of the building and from thermal properties of construction materials. The model is presented using state space notation and this form is used in the control design procedure. A sliding surface is defined by the system output and the desired trajectory. The control law is designed to force the trajectory of the system from any initial condition to the sliding surface in finite time. The trajectory of the system after reaching the sliding surface remains on it. A simulation example is included to verify the approach and to demonstrate the achievable performance improvement by the proposed solution in the temperature control in buildings.Keywords: modelling, building, temperature dynamics, sliding-mode control, sliding surface
Procedia PDF Downloads 554