Search results for: MATLAB reference model

Authors: Jing Wu, Wei Lv, Yibing Li, Yuanfan You

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The separation of speech signals has become a research hotspot in the field of signal processing in recent years. It has many applications and influences in teleconferencing, hearing aids, speech recognition of machines and so on. The sounds received are usually noisy. The issue of identifying the sounds of interest and obtaining clear sounds in such an environment becomes a problem worth exploring, that is, the problem of blind source separation. This paper focuses on the under-determined blind source separation (UBSS). Sparse component analysis is generally used for the problem of under-determined blind source separation. The method is mainly divided into two parts. Firstly, the clustering algorithm is used to estimate the mixing matrix according to the observed signals. Then the signal is separated based on the known mixing matrix. In this paper, the problem of mixing matrix estimation is studied. This paper proposes an improved algorithm to estimate the mixing matrix for speech signals in the UBSS model. The traditional potential algorithm is not accurate for the mixing matrix estimation, especially for low signal-to noise ratio (SNR).In response to this problem, this paper considers the idea of an improved potential function method to estimate the mixing matrix. The algorithm not only avoids the inuence of insufficient prior information in traditional clustering algorithm, but also improves the estimation accuracy of mixing matrix. This paper takes the mixing of four speech signals into two channels as an example. The results of simulations show that the approach in this paper not only improves the accuracy of estimation, but also applies to any mixing matrix.

Keywords: DBSCAN, potential function, speech signal, the UBSS model

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Authors: Obe Olumide Olayinka, Victor Balanica, Eugen Neagoe

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The effects of hypertension are often lethal thus its early detection and prevention is very important for everybody. In this paper, a neural network (NN) model was developed and trained based on a dataset of hypertension causative parameters in order to forecast the likelihood of occurrence of hypertension in patients. Our research goal was to analyze the potential of the presented NN to predict, for a period of time, the risk of hypertension or the risk of developing this disease for patients that are or not currently hypertensive. The results of the analysis for a given patient can support doctors in taking pro-active measures for averting the occurrence of hypertension such as recommendations regarding the patient behavior in order to lower his hypertension risk. Moreover, the paper envisages a set of three example scenarios in order to determine the age when the patient becomes hypertensive, i.e. determine the threshold for hypertensive age, to analyze what happens if the threshold hypertensive age is set to a certain age and the weight of the patient if being varied, and, to set the ideal weight for the patient and analyze what happens with the threshold of hypertensive age.

Keywords: neural network, hypertension, data set, training set, supervised learning

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Authors: K.L. Chiu, Johnny K. W. Ho, M. H. Chan, S. H. Cheung, K. H. Chan, S.K. So

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Thermal diffusivity is an important quantity in heat conduction. It measures the rate of heat transfer from the hot side to the cold side of a material. In solid-state materials, thermal diffusivity reveals information related to morphologies and solid quality, as thermal diffusivity can be affected by microstructures. However, thermal diffusivity studies on organic semiconductors are very limited. In this study, scanning photothermal deflection (SPD) technique is used to study the thermal diffusivities of different classes of semiconducting polymers. The reliability of the technique was confirmed by crossing-checking our SPD derived experimental values of different reference materials with their known diffusivities from the literature. To show that thermal diffusivity determination is a potential tool for revealing microscopic properties of organic photovoltaic semiconductors, SPD measurements were applied to various organic semiconducting films with different crystallinities. It is observed that organic photovoltaic semiconductors possess low thermal diffusivity, with values in the range of 0.3mm²/s to 1mm²/s. It is also discovered that polymeric photovoltaic semiconductors with greater molecular planarity, stronger stacking and higher crystallinity would possess greater thermal diffusivities. Correlations between thermal, charge transport properties will be discussed.

Keywords: polymer crystallinity, photovoltaic organic semiconductors, photothermal deflection technique, thermal diffusion

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Authors: Sashank Nyapati, Laura Lorente-Prieto, Maria Peiro

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The general objective of this study is to analyse the mediating role of meaningfulness in the relationships between job autonomy and job satisfaction and supportive organizational climate and job satisfaction. Theories such as the Job Characteristics Model, Conservation of Resources theory, as well as the Job Demands-Resources theory were used as theoretical framework. Data was obtained from the 5th European Working Conditions Survey (EWCS), and sample was composed of 1005 and 1000 workers from Spain and Portugal respectively. The analysis was conducted using the SOBEL Macro for SPSS (A multiple regression mediation model) developed by Preacher and Hayes in 2003. Results indicated that Meaningfulness partially mediates both the Job Autonomy-Job Satisfaction as well as the Supportive Organizational Climate-Job Satisfaction relationships. However, the percentages are large enough to draw substantial conclusions, especially that Job Meaningfulness plays an essential – if indirect – role in the amount of Satisfaction that one experiences at work. Some theoretical and practical implications are discussed.

Keywords: meaningfulness, job autonomy, supportive organizational climate, job satisfaction

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Authors: Ksenija Dumičić, Anita Čeh Časni, Irena Palić

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This paper examines economic and Information and Communication Technology (ICT) development influence on recently increasing Internet purchases by individuals for European Union member states. After a growing trend for Internet purchases in EU27 was noticed, all possible regression analysis was applied using nine independent variables in 2011. Finally, two linear regression models were studied in detail. Conducted simple linear regression analysis confirmed the research hypothesis that the Internet purchases in analysed EU countries is positively correlated with statistically significant variable Gross Domestic Product per capita (GDPpc). Also, analysed multiple linear regression model with four regressors, showing ICT development level, indicates that ICT development is crucial for explaining the Internet purchases by individuals, confirming the research hypothesis.

Keywords: European union, Internet purchases, multiple linear regression model, outlier

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Authors: Marcelo T. Okano, Jaqueline C. Bueno, Oduvaldo Vendrametto, Osmildo S. Santos, Marcelo E. Fernandes, Heide Landi

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Developing countries are increasingly finding that entrepreneurship and innovation are the ways to speed up their developments and initiate or encourage technological development. The educational institutions such as universities, colleges and colleges of technology, has two main roles in this process, to guide and train entrepreneurs and provide technological knowledge and encourage innovation. Thus there was completing the triple helix model of innovation with universities, government and industry. But the teaching of entrepreneurship and innovation can not be only the traditional model, with blackboard, chalk and classroom. The new methods and methodologies such as Canvas, elevator pitching, design thinking, etc. require students to get involved and to experience the simulations of business, expressing their ideas and discussing them. The objective of this research project is to identify the main methods and methodologies used for the teaching of entrepreneurship and innovation, to propose a framework, test it and make a case study. To achieve the objective of this research, firstly was a survey of the literature on the entrepreneurship and innovation, business modeling, business planning, Canvas business model, design thinking and other subjects about the themes. Secondly, we developed the framework for teaching entrepreneurship and innovation based on bibliographic research. Thirdly, we tested the framework in a higher education class IT management for a semester. Finally, we detail the results in the case study in a course of IT management. As important results we improve the level of understanding and business administration students, allowing them to manage own affairs. Methods such as canvas and business plan helped students to plan and shape the ideas and business. Pitching for entrepreneurs and investors in the market brought a reality for students. The prototype allowed the company groups develop their projects. The proposed framework allows entrepreneurship education and innovation can leave the classroom, bring the reality of business roundtables to university relying on investors and real entrepreneurs.

Keywords: entrepreneurship, innovation, Canvas, traditional model

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Authors: Divnesh Lingam, Devi Rengamani Seenivasagam, Prashant Chand, Caleb Yee, John Chief, Rajeshkannan Ananthanarayanan

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Telecommuting Post-Pandemic: Barriers, Solutions, and Strategies. Amidst the COVID-19 outbreak in 2020, remote work emerged as a vital business continuity measure. This study investigates telecommuting’s modern work model, exploring its benefits and obstacles. Utilizing Interpretive Structural Modelling uncovers barriers hindering telecommuting adoption. A validated set of thirteen barriers is examined through departmental surveys, revealing interrelationships. The resulting model highlights interactions and dependencies, forming a foundational framework. By addressing dominant barriers, a domino effect on subservient barriers is demonstrated. This research fosters further exploration, proposing management strategies for successful telecommuting adoption and reshaping the traditional workspace.

Keywords: barriers, interpretive structural modelling, post-pandemic, telecommuting

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Authors: Marzieh Khaleghi Baygi, Maryam Khaleghy Baygy

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The main aim of this project was designing and making sustainable architectural wearable dress inspired by reconstruction project of Bam’s Bazar in Iran. To achieve the goals of this project, Bam Bazar became the architectural reference. A mixed research method (including applied, qualitative and case studies methods) was used. After research, data gathering and considering related intellectual, mental and cultural background, the garment was modeled by using 3ds Max's modeling tools and Marvelous. After making the pattern, the wearable architecture was built and an architectural and historical building converted to a clothing. The implementation of sustainable architectural clothing, took seventeen months. The result of this project was a cloth in a new form that had been worn on its architect body. The comparison between present project and previous research were focusing on the same subjects (architectural clothing) shows some dramatic differentiations, including, the architect, designer and executive of this project was the same person who was the main researcher. Also, in this research, special attention was paid to the sustainability, volume and forms. Most projects in this subject (especially pervious related Iranian research) relied on painting and not on the volumes and forms. The sustainable immovable architecture had worn on its architect, became a cloth on a human's body that was moving.

Keywords: wearable architecture, clothing, bam bazar, space, sustainability

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Authors: Emmanouel Koumoulas, Aikaterini Rokkou, Marios Moschakis

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Theagenio" in Thessaloniki exists and works for three centuries now as a hospital. Since 1975, it has been operating as an Integrated Special Cancer Hospital and since 1985 it has been integrated into the National Health System. "Theagenio" Cancer Hospital is located at the central web of Thessaloniki residential complex and consists of two buildings, the "Symeonidio Research Center", which was completed in 1962 and the Nursing Ward, a project that was later completed in 1975. This paper examines the design of the Hospital Unit according to the requirements of the energy design of buildings. Initially, the energy characteristics of the Hospital are recorded, followed by a detailed presentation of the electromechanical installations. After the existing situation has been captured and with the help of the software TEE-KENAK, different scenarios for the energy upgrading of the buildings have been studied. Proposals for upgrading concern both the shell, e.g. installation of external thermal insulation, replacement of frames, addition of shading systems, etc. as well as electromechanical installations, e.g. use of ceiling fans, improvements in heating and cooling systems, interventions in lighting, etc. The simulation calculates the future energy status of the buildings and presents the economic benefits of the proposed interventions with reference to the environmental profits that arise.

Keywords: energy consumption in hospitals, energy saving interventions, energy upgrading, hospital facilities

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Authors: Bita Payami-Shabestari, Dariush Eslami

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The purpose of this paper is to develop a multi-product economic production quantity model under vendor management inventory policy and restrictions including limited warehouse space, budget, and number of orders, average shortage time and maximum permissible shortage. Since the “costs” cannot be predicted with certainty, it is assumed that data behave under uncertain environment. The problem is first formulated into the framework of a bi-objective of multi-product economic production quantity model. Then, the problem is solved with three multi-objective decision-making (MODM) methods. Then following this, three methods had been compared on information on the optimal value of the two objective functions and the central processing unit (CPU) time with the statistical analysis method and the multi-attribute decision-making (MADM). The results are compared with statistical analysis method and the MADM. The results of the study demonstrate that augmented-constraint in terms of optimal value of the two objective functions and the CPU time perform better than global criteria, and goal programming. Sensitivity analysis is done to illustrate the effect of parameter variations on the optimal solution. The contribution of this research is the use of random costs data in developing a multi-product economic production quantity model under vendor management inventory policy with several constraints.

Keywords: economic production quantity, random cost, supply chain management, vendor-managed inventory

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Authors: Imane Khalil, Quinn Pratt

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In a nuclear reactor, an array of fuel rods containing stacked uranium dioxide pellets clad with zircalloy is the heat source for a thermodynamic cycle of energy conversion from heat to electricity. After fuel is used in a nuclear reactor, the assemblies are stored underwater in a spent nuclear fuel pool at the nuclear power plant while heat generation and radioactive decay rates decrease before it is placed in packages for dry storage or transportation. A computational model of a Boiling Water Reactor spent fuel assembly is modeled using FLUENT, the computational fluid dynamics package. Heat transfer simulations were performed on the two-dimensional 9x9 spent fuel assembly to predict the maximum cladding temperature for different input to the FLUENT model. Uncertainty quantification is used to predict the heat transfer and the maximum temperature profile inside the assembly.

Keywords: spent nuclear fuel, conduction, heat transfer, uncertainty quantification

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Authors: S. Bagur, S. Verger, B. Mut

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Early childhood intervention (ECI) is understood as the set of interventions aimed at the child population with developmental disorders or disabilities from 0 to 6 years of age, the family, and the environment. Under the principles of family-centred practices, the members of the family nucleus are direct agents of intervention. Thus, the multidisciplinary team of professionals should work to improve family empowerment and the level of parenting skills. The aim of the present study is to analyse descriptively and differentially the level of parenting skills and family empowerment of parents using ECI services during the foster care phase. There were 135 families participating in the study. Three questionnaires were completed. The results show that the employment situation, the age of the child receiving an intervention, and the number of children in the family nucleus or the professional carrying out the intervention are variables that have a differential impact on different items of empowerment and parenting skills. The results are discussed and future lines of research are proposed, with the understanding that the initial analysis of the variables of empowerment and parenting skills may be predictors for the improvement of child development and family well-being. In addition, it is proposed to identify and analyse professional training in order to be able to adapt early care practices without depending on the discipline of the professional of reference.

Keywords: developmental disabilities, early childhood intervention, family empowerment, parenting skills

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Authors: Jan Franciszek Jacko

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This investigation presents the principle of methodological rationality of decision making and discusses the impact of an organisation's members' methodologically rational or irrational decisions on its security. This study formulates and partially justifies some research hypotheses regarding the impact. The thinking experiment is used according to Max Weber's ideal types method. Two idealised situations("models") are compared: Model A, whereall decision-makers follow methodologically rational decision-making procedures. Model B, in which these agents follow methodologically irrational decision-making practices. Analysing and comparing the two models will allow the formulation of some research hypotheses regarding the impact of methodologically rational and irrational attitudes of members of an organisation on its security. In addition to the method, phenomenological analyses of rationality and irrationality are applied.

Keywords: methodological rationality, rational decisions, security of organisations, philosophy of economics

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Authors: Fariza Yunus, Jasmee Jaafar, Zamalia Mahmud, Nurul Nisa’ Khairul Azmi, Nursalleh K. Chang, Nursalleh K. Chang

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Variation of air temperature from one place to another is cause by air temperature controls. In general, the most important control of air temperature is elevation. Another significant independent variable in estimating air temperature is the location of meteorological stations. Distances to coastline and land use type are also contributed to significant variations in the air temperature. On the other hand, in homogeneous terrain direct interpolation of discrete points of air temperature work well to estimate air temperature values in un-sampled area. In this process the estimation is solely based on discrete points of air temperature. However, this study presents that air temperature controls also play significant roles in estimating air temperature over homogenous terrain of Peninsular Malaysia. An Inverse Distance Weighting (IDW) interpolation technique was adopted to generate continuous data of air temperature. This study compared two different datasets, observed mean monthly data of T, and estimation error of T–T’, where T’ estimated value from a multiple regression model. The multiple regression model considered eight independent variables of elevation, latitude, longitude, coastline, and four land use types of water bodies, forest, agriculture and build up areas, to represent the role of air temperature controls. Cross validation analysis was conducted to review accuracy of the estimation values. Final results show, estimation values of T–T’ produced lower errors for mean monthly mean air temperature over homogeneous terrain in Peninsular Malaysia.

Keywords: air temperature control, interpolation analysis, peninsular Malaysia, regression model, air temperature

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Authors: Gupta. Ashok, V. talakokula, S. bhalla

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Rebar corrosion is one of the main causes of damage and premature failure of the reinforced concrete (RC) structures worldwide, causing enormous costs for inspection, maintenance, restoration and replacement. Therefore, early detection of corrosion and timely remedial action on the affected portion can facilitate an optimum utilization of the structure, imparting longevity to it. The recent advent of the electro-mechanical impedance (EMI) technique using piezo sensors (PZT) for structural health monitoring (SHM) has provided a new paradigm to the maintenance engineers to diagnose the onset of the damage at the incipient stage itself. This paper presents a model based approach for corrosion assessment based on the equivalent parameters extracted from the impedance spectrum of concrete-rebar system using the EMI technique via the PZT sensors.

Keywords: impedance, electro-mechanical, stiffness, mass, damping, equivalent parameters

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Authors: S. Sabzchi Asl, N. Tahouni, M. H. Panjeshahi

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Benchmarking of a process with respect to energy consumption, without accomplishing a full retrofit study, can save both engineering time and money. In order to achieve this goal, the first step is to develop a conceptual-mathematical model that can easily be applied to a group of similar processes. In this research, we have aimed to identify a set of key parameters for the model which is supposed to be used for benchmarking of combined cycle power plants. For this purpose, three similar combined cycle power plants were studied. The results showed that ambient temperature, pressure and relative humidity, number of HRSG evaporator pressure levels and relative power in part load operation are the main key parameters. Also, the relationships between these parameters and produced power (by gas/ steam turbine), gas turbine and plant efficiency, temperature and mass flow rate of the stack flue gas were investigated.

Keywords: combined cycle power plant, energy benchmarking, modelling, retrofit

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Authors: Himanshu Singh, Rishi Kant, Shantanu Bhattacharya

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This paper adopts a top-down approach for mathematical modeling to predict the size reduction from micro to nano-scale through persistent etching. The process is simulated using a finite difference approach. Previously, various researchers have simulated the etching process for 1-D and 2-D substrates. It consists of two processes: 1) Convection-Diffusion in the etchant domain; 2) Chemical reaction at the surface of the particle. Since the process requires analysis along moving boundary, partial differential equations involved cannot be solved using conventional methods. In 1-D, this problem is very similar to Stefan's problem of moving ice-water boundary. A fixed grid method using finite volume method is very popular for modelling of etching on a one and two dimensional substrate. Other popular approaches include moving grid method and level set method. In this method, finite difference method was used to discretize the spherical diffusion equation. Due to symmetrical distribution of etchant, the angular terms in the equation can be neglected. Concentration is assumed to be constant at the outer boundary. At the particle boundary, the concentration of the etchant is assumed to be zero since the rate of reaction is much faster than rate of diffusion. The rate of reaction is proportional to the velocity of the moving boundary of the particle. Modelling of the above reaction was carried out using Matlab. The initial particle size was taken to be 50 microns. The density, molecular weight and diffusion coefficient of the substrate were taken as 2.1 gm/cm3, 60 and 10-5 cm2/s respectively. The etch-rate was found to decline initially and it gradually became constant at 0.02µ/s (1.2µ/min). The concentration profile was plotted along with space at different time intervals. Initially, a sudden drop is observed at the particle boundary due to high-etch rate. This change becomes more gradual with time due to declination of etch rate.

Keywords: particle size reduction, micromixer, FDM modelling, wet etching

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Authors: Mahfoud Benzerzour, Mouhamadou Amar, Nor-edine Abriak

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In this study, a sediment was used as a secondary raw material in cement substitution with prior treatment. The treatment adopted is a physical treatment involving grinding and separation to obtain different fractions, using a dry method (1 mm, 250µm, 120µm) and washing method (250µm and 120µm). They were subsequently heat treated at temperatures of 650°C, 750°C and 850°C for 1 hour and 3 hours, in order to enable chemical activation by decarbonation or by pozzolanic activation of the material. Different characterization techniques were performed. The determination of main physical and chemical characteristics was obtained through multiple tests: particle size distribution, specific density, the BET surface area, the initial setting time and hydration heat calorimetry Langavant. The chemical tests include: ATG analysis, X-ray diffractometry (XRD) and X-ray fluorescence (XRF) which were used to quantify the fractions, phases and chemical elements present. Compression tests were performed conforming NF EN 196-1 French standard, over terms of 7 days - 14 days - 28 days and 60 days on all formulated mortars: reference mortar based on 100% CEM I 52.5N binder and cement substituted mortars with 8% and 15% by treated sediment. This clearly evidenced contribution due to the chemical activity which was confirmed by calorimetry monitoring and strength investigation.

Keywords: sediment, characterization, grinding, heat treatment, substitution

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Authors: Yu-Mi Song, Sung-Ah Kim, Dongyoun Shin

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Cities are complex systems of diverse and inter-tangled activities. These activities and their complex interrelationships create diverse urban phenomena. And such urban phenomena have considerable influences on the lives of citizens. This research aimed to develop a method to reveal the causes and effects among diverse urban elements in order to enable better understanding of urban activities and, therefrom, to make better urban planning strategies. Specifically, this study was conducted to solve a data-recommendation problem found on a Korean public data homepage. First, a correlation analysis was conducted to find the correlations among random urban data. Then, based on the results of that correlation analysis, the weighted data network of each urban data was provided to people. It is expected that the weights of urban data thereby obtained will provide us with insights into cities and show us how diverse urban activities influence each other and induce feedback.

Keywords: big data, machine learning, ontology model, urban data model

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Authors: Angela Meyer

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The operation and maintenance cost for wind parks make up a major fraction of the park’s overall lifetime cost. To minimize the cost and risk involved, an optimal operation and maintenance strategy requires continuous monitoring and analysis. In order to facilitate this, we present a decision support system that automatically scans the stream of telemetry sensor data generated from the turbines. By learning decision boundaries and normal reference operating states using machine learning algorithms, the decision support system can detect anomalous operating behavior in individual wind turbines and diagnose the involved turbine sub-systems. Operating personal can be alerted if a normal operating state boundary is exceeded. The presented decision support system and method are applicable for any turbine type and manufacturer providing telemetry data of the turbine operating state. We demonstrate the successful detection and diagnosis of anomalous operating states in a case study at a German onshore wind park comprised of Vestas V112 turbines.

Keywords: anomaly detection, decision support, machine learning, monitoring, performance optimization, wind turbines

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Authors: LaRon A. Scott, Donna M. Gibson

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Data indicate that counselor education programs in the United States do not prepare their students adequately to serve students with disabilities nor provide counseling as a related service. There is a need to train more school counselors to provide related services to students with disabilities, for many reasons, but specifically, school counselors are participating in Individualized Education Programs (IEP) and transition planning meetings for students with disabilities where important academic, mental health and post-secondary education decisions are made. While school counselors input is perceived very important to the process, they may not have the knowledge or training in this area to feel confident in offering required input in these meetings. Using a conceptual research design, a model that can be used to prepare school counseling students as related service providers and effective supports to address transition for students with disabilities was developed as a component of this research. The authors developed the Collaborative Model of Preparing School Counseling Students as Related Service Providers to Students with Disabilities, based on a conceptual framework that involves an integration of Social Cognitive Career Theory (SCCT) and evidenced-based practices based on Self-Determination Theory (SDT) to provide related and transition services and planning with students with disabilities. The authors’ conclude that with five overarching competencies, (1) knowledge and understanding of disabilities, (2) knowledge and expertise in group counseling to students with disabilities, (3), knowledge and experience in specific related service components, (4) knowledge and experience in evidence-based counseling interventions, (5) knowledge and experiencing in evidenced-based transition and career planning services, that school counselors can enter the field with the necessary expertise to adequately serve all students. Other examples and strategies are suggested, and recommendations for preparation programs seeking to integrate a model to prepare school counselors to implement evidenced-based transition strategies in supporting students with disabilities are included

Keywords: transition education, social cognitive career theory, self-determination, counseling

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Authors: Matheesha Herath, Ned Kinnear, Bridget Heijkoop, Eliza Bramwell, Alannah Frazetto, Amy Noll, Prajay Patel, Derek Hennessey, Greg Otto, Christopher Dobbins, Tarik Sammour, James Moore

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Background: Important incidental pathology requiring further action is commonly found during appendicectomy, macro- and microscopically. It is unknown whether the acute surgical unit (ASU) model affects the management and disclosure of these findings. Methods: An ASU model was introduced at our institution on 01/08/2012. In this retrospective cohort study, all patients undergoing appendicectomy 2.5 years before (traditional group) or after (ASU group) this date were compared. The primary outcomes were rates of appropriate management of the incidental findings and communication of the findings to the patient and to their general practitioner (GP). Results: 1,214 patients underwent emergency appendicectomy; 465 in the traditional group and 749 in the ASU group. 80 (6.6%) patients (25 and 55 in each respective period) had important incidental findings. There were 24 patients with benign polyps, 15 with neuro-endocrine tumour, 11 with endometriosis, 8 with pelvic inflammatory disease, 8 Enterobius vermicularis infection, 7 with low grade mucinous cystadenoma, 3 with inflammatory bowel disease, 2 with diverticulitis, 2 with tubo-ovarian mass, 1 with secondary appendiceal malignancy and none with primary appendiceal adenocarcinoma. One patient had dual pathologies. There was no difference between the traditional and ASU group with regards to communication of the findings to the patient (p=0.44) and their GP (p=0.27), and there was no difference in the rates of appropriate management (p=0.21). Conclusions: The introduction of an ASU model did not change rates of surgeon-to-patient and surgeon-to-GP communication nor affect rates of appropriate management of important incidental pathology during an appendectomy.

Keywords: acute care surgery, appendicitis, appendicectomy, incidental

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Authors: Alexandra K. Diem, Giles Richardson, Roxana O. Carare, Neil W. Bressloff

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Alzheimer's disease (AD) is the most common form of dementia and although it has been researched for over 100 years, there is still no cure or preventive medication. Its onset and progression is closely related to the accumulation of the neuronal metabolite Aβ. This raises the question of how metabolites and waste products are eliminated from the brain as the brain does not have a traditional lymphatic system. In recent years the rapid uptake of Aβ into cerebral artery walls and its clearance along those arteries towards the lymph nodes in the neck has been suggested and confirmed in mice studies, which has led to the hypothesis that interstitial fluid (ISF), in the basement membranes in the walls of cerebral arteries, provides the pathways for the lymphatic drainage of Aβ. This mechanism, however, requires a net reverse flow of ISF inside the blood vessel wall compared to the blood flow and the driving forces for such a mechanism remain unknown. While possible driving mechanisms have been studied using mathematical models in the past, a mechanism for net reverse flow has not been discovered yet. Here, we aim to address the question of the driving force of this reverse lymphatic drainage of Aβ (also called perivascular drainage) by using multi-scale numerical and analytical modelling. The numerical simulation software COMSOL Multiphysics 4.4 is used to develop a fluid-structure interaction model of a cerebral artery, which models blood flow and displacements in the artery wall due to blood pressure changes. An analytical model of a layer of basement membrane inside the wall governs the flow of ISF and, therefore, solute drainage based on the pressure changes and wall displacements obtained from the cerebral artery model. The findings suggest that an active role in facilitating a reverse flow is played by the components of the basement membrane and that stiffening of the artery wall during age is a major risk factor for the impairment of brain lymphatics. Additionally, our model supports the hypothesis of a close association between cerebrovascular diseases and the failure of perivascular drainage.

Keywords: Alzheimer's disease, artery wall mechanics, cerebral blood flow, cerebral lymphatics

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Authors: Mohamed Aniss El-Gamal

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For decades, the Global South has been facing many challenges in the fields of heritage conservation and local development. These challenges continue to increase due to rapid urbanization in historical cities, thus resulting in complicated juxtaposed contexts of heritage resources and deteriorated dwellings, where slum areas are dotted with heritage structures. While the majority of cases show the incapacity of national and local governments to deal with such contexts, few others managed to demonstrate how different levels of government can play complementary roles in the cooperation with local and international institutions as well as involving local community to achieve an integrated strategy and overcome the challenge. This paper discusses heritage conservation and local development strategies in reference to a number of case studies in cities of the Global south, i.e. Porto Alegre, Agra, Cairo and Mumbai. It further investigates main key aspects of success and failure through cross case studies analysis (Matrix). This study could help create a delineation of an integrated strategy for undertaking future interventions in similar contexts. Integrated strategies are needed to overcome the gap between heritage conservation and local development, maintaining the value of heritage structures and ensuring the quality of life for communities residing in its surroundings.

Keywords: heritage conservation, local development, the global south, regional development

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Authors: Mrinalini Amritkar, Disha Patil, Swapna Kulkarni, Sukratu Barve, Suresh Gosavi

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Micro-mixers play an important role in the lab-on-a-chip applications and micro total analysis systems to acquire the correct level of mixing for any given process. The mixing process can be classified as active or passive according to the use of external energy. Literature of microfluidics reports that most of the work is done on the models of steady laminar flow; however, the study of unsteady laminar flow is an active area of research at present. There are wide applications of this, out of which, we consider nanoparticle synthesis in micro-mixers. In this work, we have developed a model for unsteady flow to study the mixing performance of a passive micro mixer for reactants used for such synthesis. The model is developed in Finite Volume Method (FVM)-based software, OpenFOAM. The model is tested by carrying out the simulations at Re of 0.5. Mixing performance of the micro-mixer is investigated using simulated concentration values of mixed species across the width of the micro-mixer and calculating the variance across a line profile. Experimental validation is done by passing dyes through a Y shape micro-mixer fabricated using polydimethylsiloxane (PDMS) polymer and comparing variances with the simulated ones. Gold nanoparticles are later synthesized through the micro-mixer and collected at two different times leading to significantly different size distributions. These times match with the time scales over which reactant concentrations vary as obtained from simulations. Our simulations could thus be used to create design aids for passive micro-mixers used in nanoparticle synthesis.

Keywords: Lab-on-chip, LOC, micro-mixer, OpenFOAM, PDMS

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Authors: A. Chabert

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The present paper is motivated by the current influence of communicative approaches in language policies around the globe (especially through the Common European Framework of Reference), along with the exponential spread of English as a Lingua Franca worldwide. This study focuses on English language learning and teaching in the last year of primary education in Spain (in the bilingual Valencian region), Norway (in the Trondelag region), and China (in the Hunan region) and proposes a plurilingual communicative approach to ELT in line with ELF awareness and the current retheorisation of ELF within multilingualism (Jenkins, 2018). This study, interdisciplinary in nature, attempts to find a convergence point among English Language Teaching, English as a Lingua Franca, Language Ecology and Multilingualism, breaking with the boundaries that separate languages in language teaching and acknowledging English as international communication, while protecting the mother tongue and language diversity within multilingualism. Our experiment included over 400 students across Spain, Norway, and China, and the outcomes obtained demonstrate that despite the different factors involved in different cultures and contexts, a plurilingual approach to English learning improved English scores by 20% in each of the contexts. Through our study, we reflect on the underestimated value of the mother tongue in ELT, as well as the need for a sustainable ELF perspective in education worldwide.

Keywords: English as a Lingua Franca, English language teaching, language ecology, multilingualism

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Authors: Wlodzimierz Ogryczak, Michal Przyluski, Tomasz Sliwinski

Abstract:

In problems of portfolio selection, the reward-risk ratio criterion is optimized to search for a risky portfolio with the maximum increase of the mean return in proportion to the risk measure increase when compared to the risk-free investments. In the classical model, following Markowitz, the risk is measured by the variance thus representing the Sharpe ratio optimization and leading to the quadratic optimization problems. Several Linear Programming (LP) computable risk measures have been introduced and applied in portfolio optimization. In particular, the Mean Absolute Deviation (MAD) measure has been widely recognized. The reward-risk ratio optimization with the MAD measure can be transformed into the LP formulation with the number of constraints proportional to the number of scenarios and the number of variables proportional to the total of the number of scenarios and the number of instruments. This may lead to the LP models with huge number of variables and constraints in the case of real-life financial decisions based on several thousands scenarios, thus decreasing their computational efficiency and making them hardly solvable by general LP tools. We show that the computational efficiency can be then dramatically improved by an alternative model based on the inverse risk-reward ratio minimization and by taking advantages of the LP duality. In the introduced LP model the number of structural constraints is proportional to the number of instruments thus not affecting seriously the simplex method efficiency by the number of scenarios and therefore guaranteeing easy solvability. Moreover, we show that under natural restriction on the target value the MAD risk-reward ratio optimization is consistent with the second order stochastic dominance rules.

Keywords: portfolio optimization, reward-risk ratio, mean absolute deviation, linear programming

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Authors: Razyeh Behbahani, Martin L. Plumer, Ivan Saika-Voivod

Abstract:

Micromagnetic simulations based on the stochastic Landau-Lifshitz-Gilbert equation are used to calculate dynamic magnetic hysteresis loops relevant to magnetic hyperthermia applications. With the goal to effectively simulate room-temperature loops for large iron-oxide based systems at relatively slow sweep rates on the order of 1 Oe/ns or less, a coarse-graining scheme is proposed and tested. The scheme is derived from a previously developed renormalization-group approach. Loops associated with nanorods, used as building blocks for larger nanoparticles that were employed in preclinical trials (Dennis et al., 2009 Nanotechnology 20 395103), serve as the model test system. The scaling algorithm is shown to produce nearly identical loops over several decades in the model grain sizes. Sweep-rate scaling involving the damping constant alpha is also demonstrated.

Keywords: coarse-graining, hyperthermia, hysteresis loops, micromagnetic simulations

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Authors: Riccardo Angiuli, Michele Giannuzzi, Rodolfo Franchi, Gabriele Papadia

Abstract:

Temperature knowledge in machining is fundamental to improve the numerical and FEM models used for the study of some critical process aspects, such as the behavior of the worked material and tool. The extreme conditions in which they operate make it impossible to use traditional measuring instruments; infrared thermography can be used as a valid measuring instrument for temperature measurement during metal cutting. In the study, a large experimental program on superduplex steel (ASTM A995 gr. 5A) cutting was carried out, the relevant cutting temperatures were measured by infrared thermography when certain cutting parameters changed, from traditional values to extreme ones. The values identified were used to calibrate a FEM model for the prediction of residual life of the tools. During the study, the problems related to the detection of cutting temperatures by infrared thermography were analyzed, and a dedicated procedure was developed that could be used during similar processing.

Keywords: machining, infrared thermography, FEM, temperature measurement

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Authors: Abdul Rauf, Xiaoxing Liu, Rizwan Qaisar Danish, Waqas Amin

Abstract:

The core intention of this study is to analyze the linkage of training, job attitudes and motivation through a mediation model in the banking sector of Pakistan. Moreover, this study is executed to answer a range of queries regarding the consideration of employees about training, job satisfaction, motivation and organizational commitment. Hence, the association of training with job satisfaction, job satisfaction with motivation, organizational commitment with job satisfaction, organization commitment as independently with motivation and training directly related to motivation is determined in this course of study. A questionnaire crafted for comprehending the purpose of this study by including four variables such as training, job satisfaction, motivation and organizational commitment which have to measure. A sample of 450 employees from seventeen private (17) banks and two (2) public banks was taken on the basis of convenience sampling from Pakistan. However, 357 questionnaires, completely filled were received back. AMOS used for assessing the conformity factor analysis (CFA) model and statistical techniques practiced to scan the collected data (i.e.) descriptive statistics, regression analysis and correlation analysis. The empirical findings revealed that training and organizational commitment has a significant and positive impact directly on job satisfaction and motivation as well as through the mediator (job satisfaction) also the impact sensing in the same way on the motivation of employees in the financial Banks of Pakistan. In this research study, the banking sector is under discussion, so the findings could not generalize on other sectors such as manufacturing, textiles, telecom, and medicine, etc. The low sample size is also the limitation of this study. On the foundation of these results the management fascinates to make the revised strategies regarding training program for the employees as it enhances their motivation level, and job satisfaction on a regular basis.

Keywords: job satisfaction, motivation, organizational commitment, Pakistan, training

Procedia PDF Downloads 234