Search results for: hard magnet
898 Exploring Counting Methods for the Vertices of Certain Polyhedra with Uncertainties
Authors: Sammani Danwawu Abdullahi
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Vertex Enumeration Algorithms explore the methods and procedures of generating the vertices of general polyhedra formed by system of equations or inequalities. These problems of enumerating the extreme points (vertices) of general polyhedra are shown to be NP-Hard. This lead to exploring how to count the vertices of general polyhedra without listing them. This is also shown to be #P-Complete. Some fully polynomial randomized approximation schemes (fpras) of counting the vertices of some special classes of polyhedra associated with Down-Sets, Independent Sets, 2-Knapsack problems and 2 x n transportation problems are presented together with some discovered open problems.Keywords: counting with uncertainties, mathematical programming, optimization, vertex enumeration
Procedia PDF Downloads 347897 Antihypertensive Effect of Formulated Apium graveolens: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial
Authors: Maryam Shayani Rad, Seyed Ahmad Mohajeri, Mohsen Mouhebati, Seyed Danial Mousavi
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High blood pressure is one of the most important and serious health-threatening because of no symptoms in most people, which can lead to sudden heart attack, heart failure, and stroke. Nowadays, herbal medicine is one of the best and safest strategies for treatment that have no adverse effects. Apium graveolens (celery) can be used as an alternative treatment for many health conditions such as hypertension. Natural compounds reduce blood pressure via different mechanisms in which Apium graveolens extract provides potent calcium channel blocking properties. A randomized, double-blind, placebo-controlled, cross-over clinical trial was done to evaluate the efficacy of formulated Apium graveolens extract with a maximum yield of 3-n-butylphthalide to reduce systolic and diastolic blood pressure in patients with hypertension. 54 hypertensive patients in the range of 20-68 years old were randomly assigned to the treatment group (26 cases) and the placebo control group (26 cases) and were crossed over after washout duration. The treatment group received at least 2 grams of formulated powder in hard capsules orally, before each meal, 2 times daily. The control group received 2 grams of placebo in hard capsules orally, exactly as the same as shape, time, and doses of treatment group. Treatment was administrated in 12 weeks with 4 weeks washout period at the middle of the study, meaning 4 weeks drug consumption for the treatment group, 4 weeks washout and 4 weeks placebo consumption, and vice versa for the placebo control group. The clinical assessment was done 4 times, including at the beginning and ending of the drug and placebo consumption period by 24-hour ambulatory blood pressure monitoring (ABPM) holter, which measured blood pressure every 15 minutes continuously. There was a statistically significant decrease in both systolic blood pressure (SBP) and diastolic blood pressure (DBP) at the end of drug duration compared to baseline. The changes after 4 weeks on average was about 12.34 mm Hg for the SBP (P < 0.005) and 7.83 mm Hg for the DBP (P < 0.005). The results from this clinical trial study showed this Apium graveolens extract formulation in the mentioned dosage had a significant effect on blood pressure-lowering for hypertensive patients.Keywords: Apium graveolens extract, clinical trial, cross-over, hypertension
Procedia PDF Downloads 205896 Similarity Based Retrieval in Case Based Reasoning for Analysis of Medical Images
Authors: M. Dasgupta, S. Banerjee
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Content Based Image Retrieval (CBIR) coupled with Case Based Reasoning (CBR) is a paradigm that is becoming increasingly popular in the diagnosis and therapy planning of medical ailments utilizing the digital content of medical images. This paper presents a survey of some of the promising approaches used in the detection of abnormalities in retina images as well in mammographic screening and detection of regions of interest in MRI scans of the brain. We also describe our proposed algorithm to detect hard exudates in fundus images of the retina of Diabetic Retinopathy patients.Keywords: case based reasoning, exudates, retina image, similarity based retrieval
Procedia PDF Downloads 339895 The Impact of Collective Punishment on Cadets’ Psychology
Authors: Ersegün Ömer Erol
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Since the first civilizations, armies have been the most significant part of the countries. As generally known, in today’s world, people are trying hard to find the best way to educate their armies so as to prepare them effectively for the war. Due to the fact that, as rarely known, collective punishment is in fact one of the methods used commonly in militaries in order to educate personnel and cadets. In this study, it is purposed to find out the constructive and unfavorable impacts of collective punishment on cadets’ psychology and by comparing these impacts to decide whether the collective punishment is functional or not. These impacts are obtained from the questionnaire applied on cadets and personnel. The main goal of the study is to provide new point of views and more scientific information about the discussed education way-the collective punishment.Keywords: army, cadet, collective punishment, psychology
Procedia PDF Downloads 307894 The Tiv Oral Poet and Taraba Crisis: Anger, Frustration and Uncotrollable Emotionalism in Obadia Kehemen Orkor's Ballads
Authors: Peter Nave Shirga
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Obadia Kehemen Orkor’s songs that focus on the predicament of the Tiv man in Taraba in North Central Nigeria handle themes such as poverty, social inequality, discrimination and tyranny perpetrated by Jukun against the Tiv. The major thrust of his focus in the songs is the overriding longing for mutual understanding between the Jukun and Tiv that would usher in love, equality, peace and harmonious co-existence for the two antagonistic ethnic groups. This paper examines Obadia’s hard-hitting lyrics that reveal the anger, frustration and boiling emotionalism of Tiv people in Taraba state of Nigeria.Keywords: poet, crisis, emotionalism, frustration
Procedia PDF Downloads 300893 Systems Versioning: A Features-Based Meta-Modeling Approach
Authors: Ola A. Younis, Said Ghoul
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Systems running these days are huge, complex and exist in many versions. Controlling these versions and tracking their changes became a very hard process as some versions are created using meaningless names or specifications. Many versions of a system are created with no clear difference between them. This leads to mismatching between a user’s request and the version he gets. In this paper, we present a system versions meta-modeling approach that produces versions based on system’s features. This model reduced the number of steps needed to configure a release and gave each version its unique specifications. This approach is applicable for systems that use features in its specification.Keywords: features, meta-modeling, semantic modeling, SPL, VCS, versioning
Procedia PDF Downloads 439892 Rewriting the 'Sick Man' History: Imagining Chinese Masculinity in the Contemporary Military Action Genre
Authors: Yongde Dai
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The recent Chinese military action blockbusters, notably known as, Wolf Warrior/Zhan Lang (2015), Operation Mekong/Mei gong he xing dong (2016), Warrior 2/Zhan Lang 2 (2017) and Operation Red Sea/Hong hai xing dong (2018), have achieved phenomenal box-office successes and in particular, Wolf Warrior 2 became China’s highest-grossing film of all time. However, their yearly presence tends to show a paradigmic shift from China’s primacy of wen manliness (soft) to wu masculinity (hard). With the increasing cinematic exposure of a more muscular image manifesting in both the Chinese heroic soldiers and China itself as a rising global power, the backlash of the Chinese public against the proliferation of the feminized masculinity influenced by the ‘pretty-boy’ pop-culture and China’s harder approach to the current Sino-US tensions have correspondingly emerged and continued to brew. Chinese masculinity imagined in these films is one of the key factors that enable a gendered interpretation of the correlation between the Chinese on-screen fantasy and off-screen reality, that is, China’s public and official discourse about the hegemonic masculinity and non-hegemonic masculinity as well as China’s international profile on cinematic appearance and in today’s Sino-US relation. By reading closely at the four megahits as visual-audio texts with Chinese masculinity studies by Kam Louie and Geng Song, this paper attempts to examine the Chinese construction of manliness with historical accounts and argue why and how the recurrent emphasis of hard/military masculinity (wu) on screen are viewed as China’s contemporary rewriting of the ‘sick-man’ history in the film form. Through this investigation, the paper finds that the rewriting of the ‘sick-man’ history in the cinematic world through heroic brawny soldiers comes to resonate a collective anxiety of China in countering the real-life increasing feminized masculinity on the public appearance, particularly on the male celebrities. In addition, the superpower fantasy about China illuminates a hypermasculine imaginary of China as a global rising power and this coincidently echoes China’s current tougher diplomatic strategy tackling the Sino-US trade war, South China sea dispute and Huawei-US lawsuits.Keywords: Chinese masculinity, Chinese military action film, feminized masculinity, manhood and nationhood, sick man of Asia
Procedia PDF Downloads 138891 Smaa-Gaia: A Complementary Tool of the Smaa-Promethee Method
Authors: Y. de Smet, J. Hubinont
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PROMETHEE and GAIA are well-known Multiple Criteria Decision Aid methods. Given an evaluation table and preference parameters they allow to rank the alternatives, to visualize the problem, to perform sensitivity and robustness analysis, etc. Unfortunately, it is often hard for the Decision Maker (DM) to estimate the precise values of these parameters. Therefore an alternative option is to give ranges of potential values in order to apply Stochastic Multicriteria Acceptability Analysis. This has been recently studied in the context of the SMAA-PROMETHEE method. The aim of this contribution is to propose an SMAA extension of GAIA. We show how this tool can be useful and provide complementary information to SMAA-PROMETHEE. This is illustrated on a pedagogical example.Keywords: multiple criteria decision making, PROMETHEE, GAIA, SMAA
Procedia PDF Downloads 425890 Assessing Supply Chain Performance through Data Mining Techniques: A Case of Automotive Industry
Authors: Emin Gundogar, Burak Erkayman, Nusret Sazak
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Providing effective management performance through the whole supply chain is critical issue and hard to applicate. The proper evaluation of integrated data may conclude with accurate information. Analysing the supply chain data through OLAP (On-Line Analytical Processing) technologies may provide multi-angle view of the work and consolidation. In this study, association rules and classification techniques are applied to measure the supply chain performance metrics of an automotive manufacturer in Turkey. Main criteria and important rules are determined. The comparison of the results of the algorithms is presented.Keywords: supply chain performance, performance measurement, data mining, automotive
Procedia PDF Downloads 504889 Fractional Residue Number System
Authors: Parisa Khoshvaght, Mehdi Hosseinzadeh
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During the past few years, the Residue Number System (RNS) has been receiving considerable interest due to its parallel and fault-tolerant properties. This system is a useful tool for Digital Signal Processing (DSP) since it can support parallel, carry-free, high-speed and low power arithmetic. One of the drawbacks of Residue Number System is the fractional numbers, that is, the corresponding circuit is very hard to realize in conventional CMOS technology. In this paper, we propose a method in which the numbers of transistors are significantly reduced. The related delay is extremely diminished, in the first glance we use this method to solve concerning problem of one decimal functional number some how this proposition can be extended to generalize the idea. Another advantage of this method is the independency on the kind of moduli.Keywords: computer arithmetic, residue number system, number system, one-Hot, VLSI
Procedia PDF Downloads 491888 Rapid and Efficient Removal of Lead from Water Using Chitosan/Magnetite Nanoparticles
Authors: Othman M. Hakami, Abdul Jabbar Al-Rajab
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Occurrence of heavy metals in water resources increased in the recent years albeit at low concentrations. Lead (PbII) is among the most important inorganic pollutants in ground and surface water. However, removal of this toxic metal efficiently from water is of public and scientific concern. In this study, we developed a rapid and efficient removal method of lead from water using chitosan/magnetite nanoparticles. A simple and effective process has been used to prepare chitosan/magnetite nanoparticles (NPs) (CS/Mag NPs) with effect on saturation magnetization value; the particles were strongly responsive to an external magnetic field making separation from solution possible in less than 2 minutes using a permanent magnet and the total Fe in solution was below the detection limit of ICP-OES (<0.19 mg L-1). The hydrodynamic particle size distribution increased from an average diameter of ~60 nm for Fe3O4 NPs to ~75 nm after chitosan coating. The feasibility of the prepared NPs for the adsorption and desorption of Pb(II) from water were evaluated using Chitosan/Magnetite NPs which showed a high removal efficiency for Pb(II) uptake, with 90% of Pb(II) removed during the first 5 minutes and equilibrium in less than 10 minutes. Maximum adsorption capacities for Pb(II) occurred at pH 6.0 and under room temperature were as high as 85.5 mg g-1, according to Langmuir isotherm model. Desorption of adsorbed Pb on CS/Mag NPs was evaluated using deionized water at different pH values ranged from 1 to 7 which was an effective eluent and did not result the destruction of NPs, then, they could subsequently be reused without any loss of their activity in further adsorption tests. Overall, our results showed the high efficiency of chitosan/magnetite nanoparticles (NPs) in lead removal from water in controlled conditions, and further studies should be realized in real field conditions.Keywords: chitosan, magnetite, water, treatment
Procedia PDF Downloads 397887 The Use of Artificial Intelligence in Digital Forensics and Incident Response in a Constrained Environment
Authors: Dipo Dunsin, Mohamed C. Ghanem, Karim Ouazzane
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Digital investigators often have a hard time spotting evidence in digital information. It has become hard to determine which source of proof relates to a specific investigation. A growing concern is that the various processes, technology, and specific procedures used in the digital investigation are not keeping up with criminal developments. Therefore, criminals are taking advantage of these weaknesses to commit further crimes. In digital forensics investigations, artificial intelligence is invaluable in identifying crime. It has been observed that an algorithm based on artificial intelligence (AI) is highly effective in detecting risks, preventing criminal activity, and forecasting illegal activity. Providing objective data and conducting an assessment is the goal of digital forensics and digital investigation, which will assist in developing a plausible theory that can be presented as evidence in court. Researchers and other authorities have used the available data as evidence in court to convict a person. This research paper aims at developing a multiagent framework for digital investigations using specific intelligent software agents (ISA). The agents communicate to address particular tasks jointly and keep the same objectives in mind during each task. The rules and knowledge contained within each agent are dependent on the investigation type. A criminal investigation is classified quickly and efficiently using the case-based reasoning (CBR) technique. The MADIK is implemented using the Java Agent Development Framework and implemented using Eclipse, Postgres repository, and a rule engine for agent reasoning. The proposed framework was tested using the Lone Wolf image files and datasets. Experiments were conducted using various sets of ISA and VMs. There was a significant reduction in the time taken for the Hash Set Agent to execute. As a result of loading the agents, 5 percent of the time was lost, as the File Path Agent prescribed deleting 1,510, while the Timeline Agent found multiple executable files. In comparison, the integrity check carried out on the Lone Wolf image file using a digital forensic tool kit took approximately 48 minutes (2,880 ms), whereas the MADIK framework accomplished this in 16 minutes (960 ms). The framework is integrated with Python, allowing for further integration of other digital forensic tools, such as AccessData Forensic Toolkit (FTK), Wireshark, Volatility, and Scapy.Keywords: artificial intelligence, computer science, criminal investigation, digital forensics
Procedia PDF Downloads 204886 An Integrated Tailoring Method for Thermal Cycling Tests of Spacecraft Electronics
Authors: Xin-Yan Ji, Jing Wang, Chang Liu, Yan-Qiang Bi, Zhong-Xu Xu, Xi-Yuan Li
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Thermal tests of electronic units are critically important for the reliability validation and performance demonstration of the spacecraft hard-wares. The tailoring equation in MIL-STD-1540 is based on fatigue of solder date. In the present paper, a new test condition tailoring expression is proposed to fit different thermo-mechanical fatigue and different subsystems, by introducing an integrated evaluating method for the fatigue acceleration exponent. The validate test has been accomplished and the data has been analyzed and compared with that from the MIL-STD-1540 tailoring equations. The results are encouraging and reasonable.Keywords: thermal cycling test, thermal fatigue, tailoring equation, test condition planning
Procedia PDF Downloads 445885 A Framework for SQL Learning: Linking Learning Taxonomy, Cognitive Model and Cross Cutting Factors
Authors: Huda Al Shuaily, Karen Renaud
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Databases comprise the foundation of most software systems. System developers inevitably write code to query these databases. The de facto language for querying is SQL and this, consequently, is the default language taught by higher education institutions. There is evidence that learners find it hard to master SQL, harder than mastering other programming languages such as Java. Educators do not agree about explanations for this seeming anomaly. Further investigation may well reveal the reasons. In this paper, we report on our investigations into how novices learn SQL, the actual problems they experience when writing SQL, as well as the differences between expert and novice SQL query writers. We conclude by presenting a model of SQL learning that should inform the instructional material design process better to support the SQL learning process.Keywords: pattern, SQL, learning, model
Procedia PDF Downloads 253884 Design and Development of Wind Turbine Emulator to Operate with 1.5 kW Induction Generator
Authors: Himani Ratna Dahiya
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This paper contributes to design a Wind Emulator coupled to 1.5 kW Induction generator for Wind Energy Conversion System. A wind turbine emulator (WTE) is important equipment for developing wind energy conversion systems. It offers a controllable test environment that allows the evaluation and improvement of control schemes for electric generators that is hard to achieve with an actual wind turbine since the wind speed varies randomly. In this paper a wind emulator is modeled and simulated using MATLAB. Verification of the simulation results is done by experimental setup using DC motor-Induction generator set, LABVIEW and data acquisition card.Keywords: Wind Turbine Emulator, LABVIEW, matlab, induction generator
Procedia PDF Downloads 585883 A Two Phase VNS Algorithm for the Combined Production Routing Problem
Authors: Nejah Ben Mabrouk, Bassem Jarboui, Habib Chabchoub
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Production and distribution planning is the most important part in supply chain management. In this paper, a NP-hard production-distribution problem for one product over a multi-period horizon is investigated. The aim is to minimize the sum of costs of three items: production setups, inventories and distribution, while determining, for each period, the amount produced, the inventory levels and the delivery trips. To solve this difficult problem, we propose a bi-phase approach based on a Variable Neighbourhood Search (VNS). This heuristic is tested on 90 randomly generated instances from the literature, with 20 periods and 50, 100, 200 customers. Computational results show that our approach outperforms existing solution procedures available in the literatureKeywords: logistic, production, distribution, variable neighbourhood search
Procedia PDF Downloads 332882 Evaluation of External Costs of Traffic Accident in Slovak Republic
Authors: Anna Dolinayova, Jozef Danis, Juraj Camaj
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The report deals with comparison of traffic accidents in Slovak republic in road and rail transport since year 2009 until 2014, with evaluation of external costs and consequently with the possibilities of their internalization. The results of road traffic accidents analysis are realized in line with after-effects they have caused; in line with main cause, place of origin (within or out of town) and in accordance to age of people they were killed or hard, eventually easy injured in traffic accidents. Evaluation of individual after-effects is carried in terms of probability of traffic accidents occurrence.Keywords: external costs, traffic accident, rail transport, road transport
Procedia PDF Downloads 577881 Critical Analysis of the Level of Subjectivity and Objectivity While Reporting Kashmir Conflict
Authors: Pardeep Singh, N. S. Johal
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In this research paper the level of subjectivity and objectivity adopted by journalists of different newspapers of the two provinces of the Jammu and Kashmir state has been analysed. This research paper emphasized upon the professionalism of the journalists of two provinces in catering to readers of particular province. In this study it was found that Kashmir based reporters are subjective in their reporting while covering Kashmir sentiments and use hard language against New Delhi, whereas Jammu based reporters are subjective only when it comes to defend security forces and are also bitterly critical of Pakistan, accusing it of being a sponsor of violence in Kashmir.Keywords: conflict, Jammu and Kashmir, print media, reporter, critical, violence
Procedia PDF Downloads 291880 On the Analysis of Pseudorandom Partial Quotient Sequences Generated from Continued Fractions
Authors: T. Padma, Jayashree S. Pillai
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Random entities are an essential component in any cryptographic application. The suitability of a number theory based novel pseudorandom sequence called Pseudorandom Partial Quotient Sequence (PPQS) generated from the continued fraction expansion of irrational numbers, in cryptographic applications, is analyzed in this paper. An approach to build the algorithm around a hard mathematical problem has been considered. The PQ sequence is tested for randomness and its suitability as a cryptographic key by performing randomness analysis, key sensitivity and key space analysis, precision analysis and evaluating the correlation properties is established.Keywords: pseudorandom sequences, key sensitivity, correlation, security analysis, randomness analysis, sensitivity analysis
Procedia PDF Downloads 583879 Design and Development of Motorized Placer for Balloon Uterine Stents in Gynecology
Authors: Metehan Mutlu, Meltem Elitas
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This study aims to provide an automated method for placing the balloon uterine stents after hysteroscopy adhesiolysis. Currently, there are no automatized tools to place the balloon uterine stent; therefore, surgeons into the endometrial cavity manually fit it. However, it is very hard to pass the balloon stent through the cervical canal, which is roughly 10mm after the surgery. Our method aims to provide an effective and practical way of placing the stent, by automating the procedure through our designed device. Furthermore, our device does the required tasks fast compared to traditional methods, reduces the narcosis time, and decreases the bacterial contamination risks.Keywords: balloon uterine stent, endometrial cavity, hysteroscopy, motorized-tool
Procedia PDF Downloads 274878 Synthesis Using Sintering and Characterisation of FeCrCoNiZn Alloy Using SEM and Nanoindentation
Authors: Steadyman Chikumba, Vasudeva Vereedhi Rao
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This paper reports on the synthesis of FeCrCoNiZn and its characterisation using SEM and nanoindentation. The high entropy alloy FeCrCoNiZn was fabricated using spark plasma sintering at a temperature of 1100ᵒC from powders mixed for 9 hours. The powders mixture was equimolar, and the resultant microstructure had a single crystalline structure when studied under SEM. Several nano Vickers hardness measurements were taken on a polished surface etched by Nital solution. The hardness ranged from 711 Vickers to a maximum of 1773.2. The alloy FeCrCoNiZn showed a nano hardness of 1070 Vickers and a modulus of elasticity of 460.4 MPa. The process managed to fabricate a very hard material that can find applications where wear resistance is desired.Keywords: high entropy alloy, FeCrVNiZn, nanohardness, SEM
Procedia PDF Downloads 95877 Developing the Morphological Field of Problem Context to Assist Multi-Methodology in Operations Research
Authors: Mahnaz Hosseinzadeh, Mohammad Reza Mehregan
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In this paper, we have developed a morphological field to assist multi- methodology (combining methodologies together in whole or part) in Operations Research (OR) for the problem contexts in Iranian organizations. So, we have attempted to identify some dimensions for problem context according to Iranian organizational problems. Then, a general morphological program is designed which helps the OR practitioner to determine the suitable OR methodology as output for any configuration of conditions in a problem context as input and to reveal the fields necessary to be improved in OR. Applying such a program would have interesting results for OR practitioners.Keywords: hard, soft and emancipatory operations research, General Morphological Analysis (GMA), multi-methodology, problem context
Procedia PDF Downloads 294876 Hysteresis Modeling in Iron-Dominated Magnets Based on a Deep Neural Network Approach
Authors: Maria Amodeo, Pasquale Arpaia, Marco Buzio, Vincenzo Di Capua, Francesco Donnarumma
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Different deep neural network architectures have been compared and tested to predict magnetic hysteresis in the context of pulsed electromagnets for experimental physics applications. Modelling quasi-static or dynamic major and especially minor hysteresis loops is one of the most challenging topics for computational magnetism. Recent attempts at mathematical prediction in this context using Preisach models could not attain better than percent-level accuracy. Hence, this work explores neural network approaches and shows that the architecture that best fits the measured magnetic field behaviour, including the effects of hysteresis and eddy currents, is the nonlinear autoregressive exogenous neural network (NARX) model. This architecture aims to achieve a relative RMSE of the order of a few 100 ppm for complex magnetic field cycling, including arbitrary sequences of pseudo-random high field and low field cycles. The NARX-based architecture is compared with the state-of-the-art, showing better performance than the classical operator-based and differential models, and is tested on a reference quadrupole magnetic lens used for CERN particle beams, chosen as a case study. The training and test datasets are a representative example of real-world magnet operation; this makes the good result obtained very promising for future applications in this context.Keywords: deep neural network, magnetic modelling, measurement and empirical software engineering, NARX
Procedia PDF Downloads 127875 Russian Invasion of Ukraine-An analysis of Coverage in Indian Media
Authors: Dr.Prabhat Dixit Dr.Sanjay Pandey
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Russian invasion of Ukraine has hogged the limelight in both national and international media. It is expected that the news about the war, which had affected the entire world, especially its economy, will continue to dominate the coverage on TV and newspapers in the next few days, at least until the hostilities come to an end. Although the war still continues, and it is hard to predict its ending, its coverage by the Indian media has raised eyebrows, and it has been observed that the coverage lacks depth, authenticity and a majority of information was sought to be presented in a sensational manner only to attract more number of viewers. It is said that Truth is the first casualty of war. The media should, especially while airing or publishing news about the wars, exercise caution so as not to inflame the already volatile situation in the warring countries. It was also observed that there were differences in the facts and figures presented by different media outlets in the country about the war.Keywords: economy, media, russia, ukraine, war
Procedia PDF Downloads 111874 Milk Curd Obstruction as a Mimic of Necrotising Enterocolitis (NEC)
Authors: Sofia Baldelli, Aman More
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Milk curd obstruction is commonly reported as being misdiagnosed for NEC, and they predominantly mimic each other in clinical presentation, including abdominal distension, vomiting, constipation, feeding intolerance and frank or occult blood PR. Using the case of a pre-term neonate misdiagnosed with necrotising enterocolitis when in fact, they had milk curd obstruction, we compare the two diagnoses and why they are hard to differentiate, the risk factors for clinicians to consider and the different management options. The main diagnostic tool for these conditions remains the plain radiograph and here we present the original radiograph of the neonate and discuss the classical radiological features of both diagnoses. We conclude that further imaging techniques such as ultrasound might be used to improve diagnosis when X-ray is inconclusive.Keywords: milk curd obstruction, Necrotising Enterocolitis, radiology, pediatric surgery
Procedia PDF Downloads 96873 Discrete Element Simulations of Composite Ceramic Powders
Authors: Julia Cristina Bonaldo, Christophe L. Martin, Severine Romero Baivier, Stephane Mazerat
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Alumina refractories are commonly used in steel and foundry industries. These refractories are prepared through a powder metallurgy route. They are a mixture of hard alumina particles and graphite platelets embedded into a soft carbonic matrix (binder). The powder can be cold pressed isostatically or uniaxially, depending on the application. The compact is then fired to obtain the final product. The quality of the product is governed by the microstructure of the composite and by the process parameters. The compaction behavior and the mechanical properties of the fired product depend greatly on the amount of each phase, on their morphology and on the initial microstructure. In order to better understand the link between these parameters and the macroscopic behavior, we use the Discrete Element Method (DEM) to simulate the compaction process and the fracture behavior of the fired composite. These simulations are coupled with well-designed experiments. Four mixes with various amounts of Al₂O₃ and binder were tested both experimentally and numerically. In DEM, each particle is modelled and the interactions between particles are taken into account through appropriate contact or bonding laws. Here, we model a bimodal mixture of large Al₂O₃ and small Al₂O₃ covered with a soft binder. This composite is itself mixed with graphite platelets. X-ray tomography images are used to analyze the morphologies of the different components. Large Al₂O₃ particles and graphite platelets are modelled in DEM as sets of particles bonded together. The binder is modelled as a soft shell that covers both large and small Al₂O₃ particles. When two particles with binder indent each other, they first interact through this soft shell. Once a critical indentation is reached (towards the end of compaction), hard Al₂O₃ - Al₂O₃ contacts appear. In accordance with experimental data, DEM simulations show that the amount of Al₂O₃ and the amount of binder play a major role for the compaction behavior. The graphite platelets bend and break during the compaction, also contributing to the macroscopic stress. Firing step is modeled in DEM by ascribing bonds to particles which contact each other after compaction. The fracture behavior of the compacted mixture is also simulated and compared with experimental data. Both diametrical tests (Brazilian tests) and triaxial tests are carried out. Again, the link between the amount of Al₂O₃ particles and the fracture behavior is investigated. The methodology described here can be generalized to other particulate materials that are used in the ceramic industry.Keywords: cold compaction, composites, discrete element method, refractory materials, x-ray tomography
Procedia PDF Downloads 136872 Finite Element Analysis of a Modular Brushless Wound Rotor Synchronous Machine
Authors: H. T. Le Luong, C. Hénaux, F. Messine, G. Bueno-Mariani, S. Mollov, N. Voyer
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This paper presents a comparative study of different modular brushless wound rotor synchronous machine (MB-WRSM). The goal of the study is to highlight the structure which offers the best fault tolerant capability and the highest output performances. The fundamental winding factor is calculated by using the method based on EMF phasors as a significant criterion to select the preferred number of phases, stator slots, and poles. With the limited number of poles for a small machine (3.67kW/7000rpm), 15 different machines for preferred phase/slot/pole combinations are analyzed using two-dimensional (2-D) finite element method and compared according to three criteria: torque density, torque ripple and efficiency. The 7phase/7slot/6pole machine is chosen with the best compromise of high torque density, small torque ripple (3.89%) and high nominal efficiency (95%). This machine is then compared with a reference design surface permanent magnet synchronous machine (SPMSM). In conclusion, this paper provides an electromagnetic analysis of a new brushless wound-rotor synchronous machine using multiphase non-overlapping fractional slot double layer winding. The simulation results are discussed and demonstrate that the MB-WRSM presents interesting performance features, with overall performance closely matching that of an equivalent SPMSM.Keywords: finite element method (FEM), machine performance, modular wound rotor synchronous machine, non-overlapping concentrated winding
Procedia PDF Downloads 284871 Compensatory Neuro-Fuzzy Inference (CNFI) Controller for Bilateral Teleoperation
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This paper presents a new adaptive neuro-fuzzy controller equipped with compensatory fuzzy control (CNFI) in order to not only adjusts membership functions but also to optimize the adaptive reasoning by using a compensatory learning algorithm. The proposed control structure includes both CNFI controllers for which one is used to control in force the master robot and the second one for controlling in position the slave robot. The experimental results obtained, show a fairly high accuracy in terms of position and force tracking under free space motion and hard contact motion, what highlights the effectiveness of the proposed controllers.Keywords: compensatory fuzzy, neuro-fuzzy, control adaptive, teleoperation
Procedia PDF Downloads 320870 Tuning of Indirect Exchange Coupling in FePt/Al₂O₃/Fe₃Pt System
Authors: Rajan Goyal, S. Lamba, S. Annapoorni
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The indirect exchange coupled system consists of two ferromagnetic layers separated by non-magnetic spacer layer. The type of exchange coupling may be either ferro or anti-ferro depending on the thickness of the spacer layer. In the present work, the strength of exchange coupling in FePt/Al₂O₃/Fe₃Pt has been investigated by varying the thickness of the spacer layer Al₂O₃. The FePt/Al₂O₃/Fe₃Pt trilayer structure is fabricated on Si <100> single crystal substrate using sputtering technique. The thickness of FePt and Fe₃Pt is fixed at 60 nm and 2 nm respectively. The thickness of spacer layer Al₂O₃ was varied from 0 to 16 nm. The normalized hysteresis loops recorded at room temperature both in the in-plane and out of plane configuration reveals that the orientation of easy axis lies along the plane of the film. It is observed that the hysteresis loop for ts=0 nm does not exhibit any knee around H=0 indicating that the hard FePt layer and soft Fe₃Pt layer are strongly exchange coupled. However, the insertion of Al₂O₃ spacer layer of thickness ts = 0.7 nm results in appearance of a minor knee around H=0 suggesting the weakening of exchange coupling between FePt and Fe₃Pt. The disappearance of knee in hysteresis loop with further increase in thickness of the spacer layer up to 8 nm predicts the co-existence of ferromagnetic (FM) and antiferromagnetic (AFM) exchange interaction between FePt and Fe₃Pt. In addition to this, the out of plane hysteresis loop also shows an asymmetry around H=0. The exchange field Hex = (Hc↑-HC↓)/2, where Hc↑ and Hc↓ are the coercivity estimated from lower and upper branch of hysteresis loop, increases from ~ 150 Oe to ~ 700 Oe respectively. This behavior may be attributed to the uncompensated moments in the hard FePt layer and soft Fe₃Pt layer at the interface. A better insight into the variation in indirect exchange coupling has been investigated using recoil curves. It is observed that the almost closed recoil curves are obtained for ts= 0 nm up to a reverse field of ~ 5 kOe. On the other hand, the appearance of appreciable open recoil curves at lower reverse field ~ 4 kOe for ts = 0.7 nm indicates that uncoupled soft phase undergoes irreversible magnetization reversal at lower reverse field suggesting the weakening of exchange coupling. The openness of recoil curves decreases with increase in thickness of the spacer layer up to 8 nm. This behavior may be attributed to the competition between FM and AFM exchange interactions. The FM exchange coupling between FePt and Fe₃Pt due to porous nature of Al₂O₃ decreases much slower than the weak AFM coupling due to interaction between Fe ions of FePt and Fe₃Pt via O ions of Al₂O₃. The hysteresis loop has been simulated using Monte Carlo based on Metropolis algorithm to investigate the variation in strength of exchange coupling in FePt/Al₂O₃/Fe₃Pt trilayer system.Keywords: indirect exchange coupling, MH loop, Monte Carlo simulation, recoil curve
Procedia PDF Downloads 183869 An Explanatory Practice Example: The Reasons of Students Not Doing Any Extra Work
Authors: Özge Özsoy
Abstract:
Teachers usually complain that their students do not study enough to further practice the subjects they have covered in class. Teachers tend to focus on how often and hard they should study rather than finding out the main reasons why most students avoid doing any extra work to improve their skills. In this study, with the use of exploratory practice method, 40 English preparatory class students at Anadolu University will discuss this puzzle through an in-class discussion and create posters describing the reasons for and solutions to it. The overlapping data from the posters will be categorized in two sections as reasons and solutions in a final poster. The study aims at revealing the student perspective of a common puzzle that troubles many teachers.Keywords: exploratory practice, extra work, puzzle, students, teachers
Procedia PDF Downloads 335