Introducing a new column on open problems in CEM [open problems in CEM]

Computational electromagnetics (CEM) has become a big research area, which has seen rapid advances for solving more and more difficult problems in electromagnetics. We are trying to solve an incredibly wide range of real-life problems in diverse application areas, including but not limited to antennas, radar, optics, medical imaging, wireless communications, nanotechnology, metamaterials, photonic crystals, remote sensing, and electronic packaging. All of these involve electromagnetic waves and their interactions with matter via scattering, radiation, transmission, diffraction, reflection, and refraction phenomena. We are attacking these problems using our knowledge and implementing various algorithms on different sizes of computers, from notebooks to huge servers with thousands of cores. All these efforts are directed toward obtaining more-accurate and efficient solutions. However, as in all research areas, we often find ourselves sitting in front of a computer, scratching our heads when looking at the results on the screen, and asking the ultimate question: What is this?
IEEE Antennas and Propagation Magazine


On the Lagrange interpolation in multilevel fast multipole algorithm
Ergül, Özgür Salih (2006-07-14)
In this paper the Lagrange interpolation employed in the multilevel fast multipole algorithm (MLFMA) is considered as part of the efforts to obtain faster and more efficient solutions for large problems of computational electromagnetics. For the translation operator, this paper presents the choice of the parameters for optimal interpolation. Also, for the aggregation and disaggregation processes, the interpolation matrices are discussed and an efficient way of improving the accuracy by employing the poles a...
On optimal resource allocation in phased array radar systems
Ircı, Ayhan; Saranlı, Afşar; Department of Electrical and Electronics Engineering (2006)
In this thesis, the problem of optimal resource allocation in real-time systems is studied. A recently proposed resource allocation approach called Q-RAM (Quality of Service based Resource Allocation Model) is investigated in detail. The goal of the Q-RAM based approaches is to minimize the execution speed in real-time systems while meeting resource constraints and maximizing total utility. Phased array radar system is an example of a system in which multiple tasks contend for multiple resources in order to...
Prediction of Nonlinear Drift Demands for Buildings with Recurrent Neural Networks
Kocamaz, Korhan; Binici, Barış; Tuncay, Kağan (2021-09-08)
Application of deep learning algorithms to the problems of structural engineering is an emerging research field. Inthis study, a deep learning algorithm, namely recurrent neural network (RNN), is applied to tackle a problemrelated to the assessment of reinforced concrete buildings. Inter-storey drift ratio profile of a structure is a quiteimportant parameter while conducting assessment procedures. In general, procedures require a series of timeconsuming nonlinear dynamic analysis. In this study, an extensiv...
Excessive Memory Usage of the ELLPACK Sparse Matrix Storage Scheme throughout the Finite Element Computations
Akinci, Gokay; YILMAZ, ASIM EGEMEN; Kuzuoğlu, Mustafa (2014-12-01)
Sparse matrices are occasionally encountered during solution of various problems by means of numerical methods, particularly the finite element method ELLPACK sparse matrix storage scheme, one of the most widely used methods due to its implementation ease, is investigated in this study. The scheme uses excessive memory due to its definition. For the conventional finite element method, where the node elements are used, the excessive memory caused by redundant entries in the ELLPACK sparse matrix storage sche...
On efficient use of simulated annealing in complex structural optimization problems
Hasançebi, Oğuzhan (Springer Science and Business Media LLC, 2002-01-01)
The paper is concerned with the efficient use of simulated annealing (SA) in structural optimization problems of high complexity. A reformulation of the working mechanism of the Boltzmann parameter is introduced to accelerate and enhance the general productivity of SA in terms of convergence reliability. Two general and complementary parameters, referred as "weighted Boltzmann parameter" and "critical Boltzmann parameter," are proposed, Several alternative methodologies are suggested for these two parameter...
Citation Formats
Ö. S. Ergül, “Introducing a new column on open problems in CEM [open problems in CEM],” IEEE Antennas and Propagation Magazine, pp. 329–329, 2012, Accessed: 00, 2020. [Online]. Available: