Computer Aided Enginneering

Convolving the output of Discontinuous Galerkin computations with symmetric Smoothness-Increasing Accuracy-Conserving (SIAC) filters can improve both smoothness and accuracy. To extend convolution to the boundaries, several one-sided spline filters have recently been developed. This paper interprets these filters as instances of a general class of position-dependent (PSIAC) spline filters that can have non-uniform knot sequences and skip B-splines of the sequence. PSIAC filters with rational knot sequences have rational coefficients. For prototype knot sequences , such as integer sequences that may have repeated entries, PSIAC filters can be expressed in symbolic form. Based on the insight that filters for shifted or scaled knot sequences are easily derived by non-uniform scaling of one prototype filter, a single filter can be re-used in different locations and at different scales. Computing a value of the convolution then simplifies to forming a scalar product of a short vector with the local output data. Restating one-sided filters in this form improves both stability and efficiency compared to their original formulation via numerical integration. PSIAC filtering is demonstrated for several established and one new boundary filter.

This research examined the full range of tasks and activities that design engineers perform, how their working time is distributed among these, and how these issues influence their satisfaction with their work. Seventy-eight design engineers each carried a personal digital assistant (PDA) for twenty working days. Once every hour, they entered data into their PDAs concerning their current work tasks and satisfaction levels, using a work sampling approach. Work tasks were explored from multiple perspectives, yielding highly extensive and detailed results. A key finding was that design engineers' work involves considerable technical engineering work (62.92% of time) and socially collaborative work (40.37% of time). The results were discussed in terms of their implications for academic theory and organizational practice.

A strategy for adaptive control and energetic optimization of aerobic fermentors was implemented, with both air flow and agitation speed as manipulated variables. This strategy is separable in its components: control, optimization, estimation. We optimized parameter’s estimation (from the usual KLa correlation) using sinusoidal excitation of air flow and agitation speed. We have implemented parameter’s estimation trough recursive least squares algorithm with forgetting factor. We carried separate essays on control, optimization and estimation algorithms. We carried our essays using an original computational simulation environment, with noise and delay generating facilities for data sampling and filtering.

Our results show the convergence and robustness of the estimation algorithm used, improved with use of both forgetting factor and KLa dead-band facilities. Control algorithm used in our work compares favorably with PID using the integrated area criteria for deviation between oxygen molarity and critical molarity (set point). Optimization algorithm clearly reduces energetic consumption, respecting critical molarity. Integration of control, optimization and adaptive algorithms was implemented, but future work is needed for stability. Methods were defined and implemented for stability improvement. We have implemented data acquisition and computer manipulation of air flow and agitation speed for actual fermentors.

Invention of digital technology has lead to increase in the number of images that can be stored in digital format. So searching and retrieving images in large image databases has become more challenging. From the last few years, Content Based Image Retrieval (CBIR) gained increasing attention from researcher. CBIR is a system which uses visual features of image to search user required image from large image database and user's requests in the form of a query image. Important features of images are colour, texture and shape which give detailed information about the image. CBIR techniques using different feature extraction techniques are discussed in this paper.

In this paper, a state feedback controller for separately-excited DC motor (SEDM) is presented. The controller is designed using the Optimal Control approach. The motor, with and without the controller, is modeled as a multi-input multi-output (MIMO) system with state-space and transfer function representations. The control inputs are the motor armature and the motor field voltages. The controlled outputs are the motor angular speed and the motor field current. The system states are the same as the system outputs. The performance of the system with the designed controller is simulated using MATLAB (R) /SIMULINK (R) , and is compared with that of the open loop system. The results show excellent performance of the controlled system, in terms of steady-state error, output decoupling, response speed and general system behavior. Keywordsoptimal control, separately excited DC motor, motor speed, speed controller

The widespread of smart devices along with the exponential growth of virtual societies yield big digital image databases. These databases can be counter-productive if they are not coupled with efficient Content-Based Image Retrieval (CBIR) tools. The last decade has witnessed the introduction of promising CBIR systems and promoted applications in various fields. In this article, a survey on state of the art content based image retrieval including empirical and theoretical work is proposed. This work also includes publications that cover research aspects relevant to CBIR area. Namely, unsupervised and supervised learning and fusion techniques along with lowlevel image visual descriptors have been reported. Moreover, challenges and applications that emerged to support CBIR research have been discussed in this work.

In this paper, a state feedback controller for separately-excited DC motor (SEDM) is presented. The controller is designed using the Optimal Control approach. The motor, with and without the controller, is modeled as a multi-input multi-output (MIMO) system with state-space and transfer function representations. The control inputs are the motor armature and the motor field voltages. The controlled outputs are the motor angular speed and the motor field current. The system states are the same as the system outputs. The performance of the system with the designed controller is simulated using MATLAB (R) /SIMULINK (R) , and is compared with that of the open loop system. The results show excellent performance of the controlled system, in terms of steady-state error, output decoupling, response speed and general system behavior.

In this paper, a state feedback controller for separately-excited DC motor (SEDM) is presented. The controller is designed using the Optimal Control approach. The motor, with and without the controller, is modeled as a multi-input multi-output (MIMO) system with state-space and transfer function representations. The control inputs are the motor armature and the motor field voltages. The controlled outputs are the motor angular speed and the motor field current. The system states are the same as the system outputs. The performance of the system with the designed controller is simulated using MATLAB (R) /SIMULINK (R) , and is compared with that of the open loop system. The results show excellent performance of the controlled system, in terms of steady-state error, output decoupling, response speed and general system behavior. Keywordsoptimal control, separately excited DC motor, motor speed, speed controller

The ISO 9001 standard is adopted worldwide by organizations from different sectors. The ISO 9001:2015 guidelines for implementing the process approach require not only the identification of the organization processes, but also the description of their interactions as a network system. Flow charts are a common tool adopted in quality management to show the sequence flow of a process. However, they do not show interrelations between different processes. The first aim of this study is to investigate the utilization of some software engineering models to satisfy the process approach requirement in the ISO 9001:2015 standard. The second aim is to show the implementation of the ISO 9001:2015 process approach and the "Plan-Do-Check-Act" (PDCA) cycle to manage academic programs processes as a case study and to present how the proposed models can be utilized to describe the interactions between processes. Finally, the study used a semi-structured interview methodology to evaluate the proposed models based on three criteria: understandability, modifiability and process improvement.

Purpose-The waste recycling industry increasingly relies on magnetic density separators. These devices generate an upward magnetic force in ferro-fluids allowing to separate the immersed particles according to their mass density. Recently, a new separator design has been proposed that significantly reduces the required amount of permanent magnet material. The purpose of this paper is to reduce the undesired end-effects in the upward force that this design generates by altering the shape of the fer-romagnetic covers of the individual poles. Design/methodology/approach-We represent the shape of the fer-romagnetic pole covers with B-splines and define a cost functional that measures the non-uniformity in the magnetic force in an area above the poles. We apply an isogeometric shape optimization procedure, which allows us to accurately represent, analyze and optimize the geometry using only a few design variables. The design problem is regularized by imposing constraints that enforce the convexity of the pole cover shapes. It is solved by a non-linear optimization procedure. We validate the implementation of our algorithm using a simplified variant of our design problem with a known analytical solution. The algorithm is subsequently applied to the problem posed. Research limitations/implications-The shape optimization attains its target and yields pole cover shapes that give rise to a magnetic field that is uniform over a larger domain. This increased uniformity is obtained at the cost of a pole cover shape that differs per pole. This limitation has negligible impact on the manufacturing of the separator. The new pole cover shapes, therefore, lead to improved performance of the density separation. Originality/value-This paper treats the shapes optimization of magnetic density separators systematically and presents new shapes for the ferromagnetic pole covers. Due to the larger uniformity of the generated field, these shapes should enable larger amounts of waste to be processed than the previous design.

CAD (Computer Aided Design) provides a convenient mean to create designs for almost every engineering discipline. It can be used for architectural design, landscape design, interior design, civil and surveying, mechanical design, electrical engineering, plant design, industrial design, duct design, electronic circuit design, plumbing design, textile design and product design.
The following are the main objectives of CAD Lab:
To present an overview of CADD and describe its applications in different fields.
 To describe common terms associated with CADD hardware and software.
 To outline the basic principles associated with CADD and to demonstrate common drafting techniques and shortcuts used by professionals.
 To introduce the advanced capabilities of CADD and how they can be used to increase productivity.
 To provide information about the CADD industry resources.
 Model the 3-D geometric information of machine omponents including
assemblies, and automatically generate 2-D production drawings
 Understand the basic analytical fundamentals that are used to create and manipulate geometric models in a computer program,
 Improve visualization ability of machine components and assemblies before their actual fabrication through modeling, animation, shading, rendering, lighting and coloring,