Search results for "Mathematic"
showing 10 items of 24974 documents
E-NAUTILUS: A decision support system for complex multiobjective optimization problems based on the NAUTILUS method
2015
Interactive multiobjective optimization methods cannot necessarily be easily used when (industrial) multiobjective optimization problems are involved. There are at least two important factors to be considered with any interactive method: computationally expensive functions and aspects of human behavior. In this paper, we propose a method based on the existing NAUTILUS method and call it the Enhanced NAUTILUS (E-NAUTILUS) method. This method borrows the motivation of NAUTILUS along with the human aspects related to avoiding trading-off and anchoring bias and extends its applicability for computationally expensive multiobjective optimization problems. In the E-NAUTILUS method, a set of Pareto…
A novel heuristic memetic clustering algorithm
2013
In this paper we introduce a novel clustering algorithm based on the Memetic Algorithm meta-heuristic wherein clusters are iteratively evolved using a novel single operator employing a combination of heuristics. Several heuristics are described and employed for the three types of selections used in the operator. The algorithm was exhaustively tested on three benchmark problems and compared to a classical clustering algorithm (k-Medoids) using the same performance metrics. The results show that our clustering algorithm consistently provides better clustering solutions with less computational effort.
Shape Sensitivity Analysis and Gradient-Based Optimization of Large Structures Using MLFMA
2014
A fast method for computing the action of shape-differentiated electric field integral equation (EFIE) system matrix to a vector is derived exploiting the multilevel fast multipole algorithm (MLFMA). The proposed method is used in conjunction with the adjoint-variable method (AVM) to compute the shape gradient of arbitrary objective functions depending on shape of a metallic scatterer. The method is demonstrated numerically by optimizing the shape of a parabolic reflector illuminated with a half-wave dipole.
On shape differentiation of discretized electric field integral equation
2013
Abstract This work presents shape derivatives of the system matrix representing electric field integral equation discretized with Raviart–Thomas basis functions. The arising integrals are easy to compute with similar methods as the entries of the original system matrix. The results are compared to derivatives computed with automatic differentiation technique and finite differences, and are found to be in an excellent agreement. Furthermore, the derived formulas are employed to analyze shape sensitivity of the input impedance of a planar inverted F-antenna, and the results are compared to those obtained using a finite difference approximation.
In-Flow Peer Review
2014
Peer-review is a valuable tool that helps both the reviewee, who receives feedback about his work, and the reviewer, who sees different potential solutions and improves her ability to critique work. In-flow peer-review (IFPR) is peer-review done while an assignment is in progress. Peer-review done during this time is likely to result in greater motivation for both reviewer and reviewee. This workinggroup report summarizes IFPR and discusses numerous dimensions of the process, each of which alleviates some problems while raising associated concerns.
Towards a scenario of virtual mental health environments for school-aged children
2017
This study explores student teachers’ future design scenarios focusing on promoting children’s mental health literacy through virtual reality (VR) environments. VR use is on the verge of many breakthroughs in several areas of lived experience. One such area pertains to educational contexts. Student teachers were chosen as the subjects of this study due to the likelihood that they will be the primary users and disseminators of these emerging technologies in educational contexts. The students created five types of future scenarios that contained different environments and activity modes, including those that are still not yet feasible to realize with current technological capabilities. The ai…
Understanding beginners' mistakes with Haskell
2015
AbstractThis article presents an overview of student difficulties in an introductory functional programming (FP) course taught in Haskell. The motivation for this study stems from our belief that many student difficulties can be alleviated by understanding the underlying causes of errors and by modifying the educational approach and, possibly, the teaching language accordingly. We analyze students' exercise submissions and categorize student errors according to compiler error messages and then manually according to the observed underlying cause. Our study complements earlier studies on the topic by applying computer and manual analysis while focusing on providing descriptive statistics of d…
On the motivations to enroll in doctoral studies in Computer Science — A comparison of PhD program models
2013
While student motivation has been intensively researched, only a few studies cover motivation at doctoral level and even less focus on doctoral education in Computer Science. In this paper we investigate the motivation of graduate students to pursue doctoral studies specifically in Computer Science. We interviewed 63 doctoral students, from two different doctoral models (traditional and structured) in Finland and Austria, on their initial reasons and experiences that led them to enroll in doctoral studies. We identified five disjoint main motivational drivers that relate with different aspects of extrinsic and intrinsic motivation. Together with a measure of the strength of their initial mo…
Revisiting rainfall to explore exam questions and performance on CS1
2015
The Rainfall problem comprises small tasks that have been used to investigate student performance in introductory programming. We conducted several kinds of analyses to inform our understandings of student performance in CS1 relating to this problem. We analyzed implementation approaches and program errors, as in related studies, and also explored the role of test writing vis-a-vis the most common student error. Finally, using correlation analyses and manual inspection of the exam answers, we studied how well the Rainfall problem served as an exam question. The students' implementation choices reflected their familiarity with particular loop constructs, while the single most common error co…
Interface Detection Using a Quenched-Noise Version of the Edwards-Wilkinson Equation
2015
We report here a multipurpose dynamic-interface-based segmentation tool, suitable for segmenting planar, cylindrical, and spherical surfaces in 3D. The method is fast enough to be used conveniently even for large images. Its implementation is straightforward and can be easily realized in many environments. Its memory consumption is low, and the set of parameters is small and easy to understand. The method is based on the Edwards-Wilkinson equation, which is traditionally used to model the equilibrium fluctuations of a propagating interface under the influence of temporally and spatially varying noise. We report here an adaptation of this equation into multidimensional image segmentation, an…