Simulation Symposium Abstracts

Keynote speech abstracts


Dr. Paul Steinmann, “Computationally Assisted Understanding of Neuromechanics"

The characteristically folded surface morphology is a classical hallmark of the mammalian brain. During development, the initially smooth surface evolves into an elaborately convoluted pattern, which closely correlates with brain function and serves as a clinical indicator for physiological and pathological conditions. Despite their significance, the regulators of brain folding in evolution and development remain poorly understood. Here, we combine analytical, computational, and experimental analyses to show that physical forces play an important role in pattern selection. We experimentally characterize the mechanical response of brain tissue under multiple loading conditions and closely consider cellular processes during brain development to establish a mechanical model of brain growth. The model consists of a morphogenetically growing outer cortex and a stretch-induced growing inner core. Through computational analyses we explore growth-induced primary and secondary instabilities and provide new evidence towards the emergence of advanced, higher order wrinkling modes. Our results emphasize that the key regulators of brain folding include cortical thickness, brain geometry, stiffness, and growth. The mechanical model explains why larger mammalian brains tend to be more convoluted than smaller brains. Numerical predictions agree well with the classical pathologies of lissencephaly and polymicrogyria. Combining physics and biology holds promise to further advance our understanding of human brain development, to enable early diagnostics of cortical malformations, and to improve treatment of neurodevelopmental disorders such as epilepsy, autism, and schizophrenia.

Prof. Imad Barghouti, "Monte Carlo Simulation: Space Physics Applications"

The Monte Carlo method was shown to be a very powerful technique in solving the Boltzmann equation by particle simulation. Its simple concept, straightforward algorithm, and its adaptability to include new features (such as, gravity, electric field, geomagnetic field, and different collision models) make it useful tool in space plasma physics, and a powerful test of results obtained with other mathematical methods. We have used Monte Carlo method to solve Boltzmann equation, which describes the motion of a minor ion in a background of ions under the effect of external forces, wave-particle interactions and Coulomb collisions with background ions. As an application, Monte Carlo simulation has been adapted to determine the ion velocity distribution function, ion density, ion drift velocity, ion temperatures, and ion heat fluxes for ion outflow along open geomagnetic field lines.

Dr. Ahmed Khamayseh, "Framework of Simulation in Applied Sciences and Engineering"

Advanced scientific and engineering applications have added a new dimension to the challenges of simulation complexities associated with numerical methods, algorithms, and solvers for HPC applications. A framework of enabling interoperable computational tools comprised of computing integrated services, mathematical component services, data management services,  and applications impact will presented. The overall goal is to enable the scientific community to more easily use modern dynamic computational tools to achieve the targeted simulation goal. In particular, the premise of this talk is to present an overview of the challenges in geometry, meshing, adaptivity, and intermesh data transfer for multiphysics simulation and presents methodologies of tackling some of the issues that arise. In addition, we will present ongoing research in the development of adaptive refinement methods tailored to application areas and highlight its use in several different simulation fields; e.g., climate modeling, astrophysics simulation, neutron science, and materials science. The adaptive computational approach and its underlying methods are attractive to many application areas when solving three-dimensional, multi-physics, multi-scale, and time-dependent problems.

Dr. Areej Abuhammad, "Utilization of IMAN1 in Protein Structural Studies and Drug Discovery"

Protein X-ray crystallography is an essential technique in drug discovery. It is the most powerful method for 3D-structure determination at an atomic level. This cutting-edge technology has led to 28 Nobel Prizes in the last century. X-ray diffraction captures details from every atom in the crystal, which usually encompasses a huge number of molecules. Handling of such data on a standard PC is challenging and very inconvenient. At IMAN1 we have built a powerful machine to run all software modules required for the handling and processing of protein crystallographic data and eventually for structure determination. The established structures can be used in in-silico drug discovery efforts. 

Prof. Ahmad Hujeirat, "Converting Conditionally into Unconditionally-stable and Robust Numerical Solvers"

We present a unified numerical approach for modelling powerful jets in quasars and active galactic nuclei, where plasmas are observed to propagate at ultra-relativistic speeds. The numerical approach is based on Krylov subspace iterative method, using a sequence of precondionings J j {A ...A ...I}, that runs from the full Jacobian down to the identity matrix. Within the framework of preconditioned defect-correction strategy, the sequence corresponds to a family of conditionally and unconditionally stable numerical schemes, whose degree of implicitness decreases gradually from the strongly time-implicit case down to the purely time explicit solution procedure. The well-known Courant-Friedrichs-Lewy condition turns out to be a special requirement for stably inverting simple matrices. When using parallelization and adaptive mesh refinement to enhance efficiency, strongly implicit methods turn out to be, not only robust, but also more efficient than their time explicit counterparts in the high Lorenz factor regimes and therefore more qualified for modelling powerful jets from stellar and supermassive black holes.

Prof. Osama Ata, "Simulation of Antennas and Indoor Propagation Modeling at Palestine Polytechnic University"

Antennas constitute an important part in any wireless communication system as they convert the electronic signals, that propagate in the RF transceiver, into electromagnetic waves, that propagate in the free space, with minimum loss. They have wide applications in the military and civic sectors and some of them are used when nothing else is possible, as in communication with a missile or over rugged mountain terrain where cables are expensive and take a long time to install. The performance characteristics of the parent system are heavily influenced by the selection, position and design of the antenna suite. To understand the concept of antenna one should know the behavior of electromagnetic waves in free space. We cover antenna classifications (based on frequency, aperture, polarization and radiation pattern), and their performance parameters (gain, directivity, beamwidth, radiation pattern, VSWR/return loss, polarization, efficiency). In recent years, micro strip antennas have played an important role in wireless communication systems because of their many advantages like light weight, low profile, low cost, easy integration with planar structure and easy fabrication. So, it is very much essential to know all the aspects of micro strip antennas, especially the design and performance issues. The design issues include micro strip antenna dimensions, feeding techniques and various polarization mechanisms whereas the performance issues include gain enhancement, bandwidth issues and miniaturization techniques.

Microwave simulation has increasingly become indispensable in the design and performance analysis of microstrip antennas. CST MICROWAVE STUDIO (CST-MWS) is a worldwide software tool, based on the finite integration technique (FIT), a very general approach, which describes Maxwell's equations on a grid space and can be written in time domain as well as in frequency domain and is not restricted to a certain grid type. A large step forward in the area of meshing was introduced by a method called "perfect boundary approximation (PBA)" and it allowed a technique to represent curves and inclines very accurately within a coarse discretization. One main advantage of the time domain solver of CST MWS is that the resource requirement only scales linear with the numbers of mesh nodes and therefore the problem size. Thus it is possible to handle large radiating structures and even complete arrays with more than some hundreds of radiating elements. The ability to extract a high resolution of broadband antenna data is a result of the time domain solver's ability to define and calculate a large number of farfield monitors in one single simulation run. This represents a significant performance advantage compared to non-time domain methods which entail the simulation of a large number of discrete frequencies for the broadband data extraction. However, despite having the ability to solve a vast variety of problems, other techniques have shown advantages for certain class of problem. A frequency domain method based on hexahedral and tetrahedral meshing was introduced to focus on the subset of problems where this technique excelled, e.g. in narrow band antennas, electrically smaller devices or phased array unit cells. Both solvers; time and frequency domain, are completely available on a common user-interface. Examples included and demonstrated here are UWB antennas, RFIDs, and phased arrays antennas.

We will demonstrate some of the microstrip antenna research we conducted at Palestine Polytechnic University for some promising applications; mobile and Wi-Fi communications, breast cancer detection and satellite communications. Notably, a microstrip antenna for breast tissue tumor detection was designed and simulated, using CST-MWS. An FR4 dielectric material, was used to fabricate two types of patch antennas; one with a central stub and transmission line feed and another with an optimum offset combination. Our measured results showed a lower resonant return loss of -37.5 dB with a real human breast contact, compared to -24 dB, with a fabricated, 8 facet cone phantom. On a different account, multiband applications was realized as a result of designing a double U-slot rectangular patch antenna. CST-MWS software was used to design the microstrip antenna with an off-set transmission line feed and simulate return loss and radiation patterns. The antenna was fabricated in-house using a printed board CNC machine and was measured and compared for return loss using a portable network analyzer. The radiation patterns were measured using a laboratory antenna measurement system. The fabricated antenna was installed on a networked WiFi access point, and tested as far as average received power versus distance range. The average received power versus distance, when tested using a WiFi access point operating in the 2.4 GHz band, showed a relative 10 dB improvement, and hence a wider space coverage, when a U-slot antenna was installed.

On the propagation modeling side, we will show the extended-AMATA indoor propagation model, we recently developed, that generally describes signal power performance in university and office type buildings. A sample of four different multi-floor building structures that have a stone block type outer wall was chosen; 3 buildings at Wadi Hariya university campus and Al-Ahli hospital in Hebron. Those flat roofed, stone built, multi floor buildings are very common, not only in Palestine, but probably in vast areas in the Middle East region. The new novel model benefits over a previous one (we called the AMATA model), which was applied at 900 MHz, in that it can be extended to cellular base-stations, transmitting at 1800 MHz frequency and outdoor Wi-Fi basestations, as opposed to indoor access points, transmitting at 2.4 GHz. The work is of paramount importance to cellular and Wi-Fi network operators, transmitting at 900/1800 MHz (e.g. Jawwal and Al-Wataniya Mobile) and at 2.4 GHz frequency bands. Our new model can be applied with high confidence to buildings, similar to the sample of buildings, we measured.