Abstract:MapReduce (MR) is a criteria of Big Data processing model with parallel and distributed large data sets. This model knows difficult problems related to low-level and batch nature of MR that gives rise to an abstraction layer on top of MR. Therefore, several High-Level MapReduce Query Languages built on top of MR provide more abstract query languages, extending the MR programming model. These generic High-Level MapReduce Query Languages remove the burden of MR programming away from the developers and make a soft migration of existing competences with SQL skills to Big Data environment. In this paper, we investigate the very used High-Level MapReduce Query Languages built directly on top of MR that translate queries into executable native MR jobs. We evaluate the performance of the four presented High-Level MapReduce Query Languages : JAQL, Hive, Big SQL and Pig regarding their insight perspectives and ease of programming. The baseline metrics reported are increasing input size, scale-out number of nodes and controlling number of reducers. Through our experimental results, we study technical advantages and limitations for each High-Level MapReduce Query Languages. Finally, we make a summary for developers to choose the High-Level MapReduce Query Languages which fulfill their needs and interests.
Abstract:A356 alloy has a wide range of applications due to an excellent combinations of castability and mechanical properties. A356 alloy matrix composites are widely used for high performance applications such as in automotive, military, aerospace and electricity industries. In this study, A356 aluminum alloy MMCs reinforced with different weight fractions of Al2O3 particles were fabricated by stir casting method. The Influence of casting mould wall thickness during solidification on the properties and microstructure of A356 alloy reinforced with alumina particles on the microstructure and mechanical properties of the produced composites will be studied. The mould wall thickness is one of the casting parameters, which affects the rate of solidification. As the mould wall thickness increases the solidification takes place at fasterrate. The rate of cooling also increases as the mould wall thickness increases, and, consequently, the grains become finer. The microstructure of the casting shows a fineto coarse grains from the outer (near to the inner mould wall) into the inner surface of the casting, which results a higher michardness near to the inner mould wall. The effect of reinforcement content on the microstructure, mechanical properties, and wear resistance of composites will be also investigated. The density measurements of the composites showed that the amount of porosity in the composites is increased with increasing the weight fraction of reinforcement particles. From wear results, it is revealed that the wear rate of the composites is decreased significantly with increasing the content of Al2O3 particles.
Abstract:This paper presents an Application Based Active Learning (ABAL) methodology on Power Electronics (PE) and Electric Machines (EM) as a hybrid laboratory course for the undergraduate students to design and implement the real-world engineering problems. The ABAL is a type of active learning which is a branch of Learner-centered teaching (LCT). The DC/DC converter along with the speed control of DC separately excites the motor. In addition, a DC/AC converter is designed to control the speed of an induction motor. The results are then investigated on a hardware platform under the ABAL experimental methodology. This paper also discusses the problem identification selection of the equipment, circuit design, hardware mounting and critical analysis of the results acquired from the hybrid laboratory. The ABAL methodology was evaluated based on student satisfaction, feedback, grades and interest to solve the real-world problem rather than cramming the engineering concepts and fulfill so-called lab routine and tasks.
Abstract:Worldwide there is a global substitution of metal products, structural elements with composite materials in various industries, especially in the field of shipbuilding. The prospects for the use of polymer composite materials are confirmed by the fact that in the world these materials are widely used and their share in production continues to grow
Abstract:Deep drawing is the process of changing a flat precut sheet metal into hollowed vessels. Their production are always accorded with material waste despite observing the recommended production and engineering features guides. Causes were investigated and solutions proffered. Investigation revealed that both less and bigger blank diameter than the required were the factors that caused the excessive material waste. This study investigated types of symmetrical shell in literature, which were twelve, their geometrical parameters and ascertained mathematical models for each shape blank diameter. These models were integrated to form a logic for blank diameter prediction. It brought a reduction of 47% to material and save cost of N507,435:50 (which is US$ 3,352.80 at the exchange rate of N151.377 as at the time of this study) when compared with the existing blank diameter and cost of production. A lot of materials were discovered as waste during visits to industries producing symmetrical shells products on their invitation. These excess waste in materials negatively affected their optimal production as well as profit expected to be generated. These industries called for assistances of industrial engineers on how this excess waste can be controlled, since it cannot be totally eliminated. This is a gap in literature that this study fills; the research responded to this request by proffering solutions to the problem by identifying different geometric shapes and their relative parameters required in deep drawing process design; selected the appropriate mathematical model, for each geometrical shape, for blank diameter determination; integrated these shell models to form global model for predicting the optimal blank diameter required for each geometrical shape identified. Different types of shapes, dimension parameters and their mathematical models, used in solving this problem, were tabulated; the model was then observed on a client that made request for types: A, D, G, and J. The results were compared with the initial results under same types and substantial improvement, both in material and cost, was realized. The developed model was observed on the request of a client for shell types: A, D, G, and J; the results were compared with the results of old, and there were appreciable percentage improvement of: 41, 36, 45 and 21 for these shell types.
Abstract:The advancement in the world of global satellite systems has enhanced the accuracy and reliability between various constellations. However, these enhancements have made numerous challenges for the receivers’ designer. For instance, comparing the acquisition and tracking of the Galileo signals turn into relatively complex processes after the utilization of Alternate-Binary Offset Carrier (AltBOC) modulation scheme. This paper presents an efficient and unique method for comparing baseband signal processing of the complex receiver structure of the Galileo E5 AltBOC signal. More specifically, the data demodulation has attained after comparing the noisy satellite data sets with the clean data sets. Moreover, the paper presents the implementation of signal acquisition, code tracking, multipath noise characteristics, and carrier tracking for various datasets of satellite after the eradication of noise. The results obtained in the paper are promising and provide the through treatment to the problem.
Abstract:Gallstone induced small bowel obstruction is a rare condition but devastating disease, which usually occurred in obesity or NSAID-chronic-using patients. The poor controlled diabetes mellitus is a significant risk factor to hind the typical sign and symptoms of gallstone ileus. These patients may have high risk of sepsis and death. Here, we present a case of a 89-year-old male who presented with diabetes mellitus type 2 under irregular controlled came to the emergency room with diffuse abdominal dull pain. The pain initially localized epigastric area and progressed to diffuse abdomen without radiating to the back. After surveying, the abdominal plain film revealed ileus pattern and abdominal computed tomography showed gallstone ileus. This paper also describes the clinical features of gallstone ileus and highlight the atypical symptoms in diabetes mellitus patient for physicians to timely intervention for sepsis.
Abstract:Backgraound: End stage renal disease (ESRD) is considered to be an independent risk factor for early and late survival after coronary artery bypass grafting. Perioperative death ranges from 5% to 20% in ESRD patients, which is roughly 3-fold greater than that in non-ESRD patients. Objectives: Retrospectively analyzed the peroperative morbidity and mortality rates, and short-term results of dialysis patients undergoing isolated off-pump coronary artery by-pass surgery (OPCAB) at our institution in the past 8 years and compared clinical outcome with that of dialysis patients undergoing isolated conventional on-pump coronary artery by-pass surgery (ONCAB) during the same time period. Design:Fifty-five patients requiring dialysis who underwent coronary bypass graft surgery (CABG) at our institution from 2000-2017 were enrolled in this study. Patients (Materials) and Methods: ONCAB was performed for 74 patients and OPCAB for 36. Comparisons were made between patients undergoing on-pump and off-pump bypass surgery with respect to demographics, risk factors, and outcomes. Main outcome measures: This study compares outcomes of coronary artery bypass grafting in dialysis patients with on-pump and off-pump techniques. Results: Groups were compared in terms of peroperative characteristics, transfusion requirement, blood loss and duration of intensive care unit stay was statistically significantly higher on ONCAB group from OPCAB group. (p<0.05 ) Postoperative CK and CKMB values of ONCAB group was significantly higher from OPCAB group (p=0.003). Postoperative CK of ONCAB group was observed to have a statistically significant increase from preoperative values (p<0.05). Conclusion; When compared to conventional ONCAB group, OPCAB patients had less drainage, shorter intensive care unit stay, lower CK and CKMB elevation, and less requirement of IABP in patients reguiring dialysis.
Abstract:In Morocco, agriculture is the main source of life for most people. Such as, to irrigate agriculture, they use engines that consume fossil energy to pump well water . While, this means of irrigation is not profitable because of the high cost of the fuels used . More, it has serious consequences on our environment. For this reason, we thought about applying alternative energy, which responds well to the problems mentioned. This is photovoltaic energy (PV) through the installation of PV pumping stations for agricultural irrigation and domestic use [3-4]. The choice of this type of energy was based on several factors: Sunny region, moderate temperature, this energy is profitable. Our contribution will be at the level of scientific research through the study of the operation of PV installations (efficiency, loss of power ...) and the application of prototypes made in the laboratory to optimize the operation of these PV installations.
Abstract:Blind techniques play a crucial role in digital signal processing, especialy in identification and equalization, in termes of observed informations with acceptable precision in noisy environment, mainly this field of sciences has already been one of the most powerful technologies, it had a revolutionary changes in the last century. In this work, we propose and implement a new algorithm based on blind techniques for channel identification and signal equalization. Our algorithm is a mixture between two established algorithms obtained previousely, Some numerical experiments are presented to clarify performance of our approach under different channels, it was tested for different cases and for different type of channels: BRAN A et BARAN E. Our results, compared to priviously published works, gives better channel estimation and signal equalization