Array Layout Research Articles

Analysis of GPU Data Access Patterns on Complex Geometries for the D3Q19 Lattice Boltzmann Algorithm

GPU performance of the lattice Boltzmann method (LBM) depends heavily on memory access patterns. When implemented with GPUs on complex domains, typically, geometric data is accessed indirectly and lattice data is accessed lexicographically. Although there are a variety of other options, no study has examined the relative efficacy between them. Here, we examine a suite of memory access schemes via empirical testing and performance modeling. We find strong evidence that semi-direct is often better suited than the more common indirect addressing, providing increased computational speed and reducing memory consumption. For the layout, we find that the Collected Structure of Arrays (CSoA) and bundling layouts outperform the common Structure of Array layout; on V100 and P100 devices, CSoA consistently outperforms bundling, however the relationship is more complicated on K40 devices. When compared to state-of-the-art practices, our recommendations lead to speedups of 10-40 percent and reduce memory consumption up to 17 percent. Using performance modeling and computational experimentation, we determine the mechanisms behind the accelerations. We demonstrate that our results hold across multiple GPUs on two leadership class systems, and present the first near-optimal strong results for LBM with arterial geometries run on GPUs.

Electronic Beam-Scanning Strip-Coded Graphene Leaky-Wave Antenna Using Single Structure

In this paper, a reconfigurable graphene leaky-wave antenna (GLWA) with electronic beam scanning capability for THz communications system is proposed. It consists of graphene strips printed on silicon oxide substrate and is fed by a planar H-plane horn antenna. The tunable graphene conductivity using DC-bias is used to control the GLWA-radiated beam direction without changing its physical structure. By selecting the proper periodicity of the biased/unbiased graphene strips (i.e., codes) of the GLWA, the beam direction, scanning range, gain, and SLL are changed without changing the array layout. A parametric study on the effect of GLWA dimensions on the radiation characteristics is studied. The radiated beam is electronically scanned from − 68° to 26° at a fixed frequency of 2 THz using different codes. The proposed antenna is simple in design, easy to control via the bias/unbiased periodic graphene strips. It has a compact size of $$1350\times 300\times 35 {{\mu m}}^{3}$$ . The GLWA coded by 1111111000 has a peak gain of 19.7 dBi, SLL of − 10.8 dB and beam radiated in 8° direction at 2 THz. The code 11111000 has beam scanning from − 35° to − 3° with frequency varying from 1.8 to 2.2 THz with 20.0 dBi gain. An investigation of the radiation characteristics of different codes of GLWA is introduced. The effect of GLWA feeding with substrate integrated waveguide (SIW) H-plane horn antenna that is compared with the ideal wave-port is studied. The GLWA with code 11111000 introduces BW of 21.95% (1.72–2.15 THz) with good impedance matching. The antenna structure is full-wave simulated and studied using the finite integral technique.

Investigations on the hydrodynamic interference of the multi-rotor vertical axis tidal current turbine

In the development of tidal energy, in order to extract more energy in the limited tidal farm, large-scale deployment of tidal current turbine is needed. In this paper, based on the PimpleDyMFoam solver in Open Source Fluid Dynamics Software (OpenFOAM), an effective numerical method is proposed for the two-dimensional VATCT (Vertical Axis Tidal Current Turbine). Secondly, the symmetrical simplified model is introduced to simulate the multi-rotor VATCT array. The interaction and wake characteristics of each turbine in different array layout schemes are studied in order to enhance the understanding of the interaction between multiple turbines. It is well known that the interaction between multiple turbines improves the overall power conversion efficiency, so it is of great significance to conduct in-depth research. The CFD numerical simulation results of the multi-rotor turbine array are compared in three aspects: blade force, wake flow field and power conversion efficiency. The results show that the power conversion efficiency of multi-rotor turbine array is higher than that of the stand-alone turbine. The smaller the spacing of each turbine in the multi-rotor turbine, the larger the overall output power. The single-row multi-rotor array in the form of opposite-rotation is more advantageous for energy acquisition. The analysis of the multi-rotor array from the aspect of the wake flow field can provide some insights into the reasons for the increased power conversion in the array. In this paper, force characteristics, wake characteristics and the energy efficiency of multi-rotor VATCT under different array layouts are considered comprehensively. The array optimization scheme proposed from the point of view of hydrodynamics will provide technical insights for the industrialization of large-scale VATCT array farm.

Design of high efficiency diode laser module for wireless power transmission

Laser wireless power transmission in unmanned aerial vehicle, satellite station and lunar robot power supply has potential application prospect, whose efficiency becomes the key to the application bottleneck. In order to improve the electro-optic conversion efficiency of the transmitter, the spot uniformity and the effective power ratio in window at the receiver, a design scheme of high efficiency diode laser for the transmitter of laser wireless power transmission was proposed. A high power and high efficiency diode laser system was designed, which is based on space combination with high efficiency, what’s more, the unevenness of the intensity at the receiving end can be optimized to 0.207, and the power ratio in the effective window is more than 94%. A laser wireless power transmission experimental device was built, whose power is over kilowatt, and the rectangular spot was outputted directly by diode laser system, which is matched with rectangular photovoltaic cell, thus the battery array layout rate was improved. The feature of multi-beam modulation was used to improve uniformity of the intensity, which is beneficial to improve the optic–electro conversion efficiency of battery and simplify the power management at the receiving end. The design and research provide reference for the practical application of laser wireless power transmission.

Concentric Ring Array Synthesis for Low Side Lobes: An Overview and a Tool for Optimizing Ring Radii and Angle of Rotation

A comprehensive review on the approaches for synthesizing low side lobe concentric ring array (CRA) antennas is given. An Iterative Convex Optimization (ICO) based array layout synthesis technique is proposed for peak side-lobe level (PSLL) minimization over a given circular field-of-view in steerable uniform-amplitude concentric ring array (UA-CRA) antennas. For a given number of rings and number of uniformly-distributed elements in each ring, the ICO algorithm optimizes the ring radii and angle of rotation, with possible constraints on the minimum element separation and largest array size. As compared to the existing UA-CRA synthesis techniques, the proposed method presents unique features as it combines the capability of optimization of angle of rotation of the rings and PSLL minimization for multiple elevation scan angles in a computationally-efficient and easy-to-solve procedure. Through numerical design examples, it is demonstrated how the ICO technique can be effectively used (i) to synthesize sparse UA-CRA topologies generating low PSLL steerable beams, and (ii) to assess and improve the PSLL suppression performance of various known optimization algorithms. Based on the UA-CRA topologies synthesized via competitive methods in the recent literature, a new set of improved array topologies are presented.

Array modeling and testing of fixed OWC type Wave Energy Converters

If wave energy technology is to mature to commercial success, array optimization could play a key role in that process. This paper outlines physical and numerical modeling of an array of five oscillating water column wave energy converters. Numerical model simulations are compared with experimental tank test data for a non-optimal and optimal array layout. Results show a max increase of 12% in average power for regular waves, and 7% for irregular waves between the non-optimized and optimized layouts. The numerical model matches well under many conditions; however, improvement is needed to adjust for phase errors. This paper outlines the process of numerical and physical array testing, providing methodology and results helpful for researchers and developers working with wave energy converter arrays.

On the Design of Sparse Arrays With Frequency-Invariant Beam Pattern

Beamformer performs spatial filtering to preserve the desired signal while suppressing interfering signals and noise arriving from directions other than the direction of interest. However, the beam pattern of the conventional beamformer is dependent on the frequency of the signal. It is common to use dense and uniform arrays for a broadband signal to achieve some essential performances together, such as frequency-invariant, white noise gain, directivity factor, front-to-back ratio, etc. Recently, the interest in sparse arrays is growing, mainly due to the capacity to reduce the number of sensors. Nevertheless, in general, finding a suitable sparse array layout is still a challenging task. Many studies have focused on optimization procedures to seek the sparse array deployment. This paper presents an alternative approach to determine the location of sensors. Starting with a weight spectrum of a virtual uniform array, some techniques are used, such as analyzing the weight spectrum to determine the critical sensors, applying the clustering technique to group the sensors into the different groups, and selecting the representative sensors for each group. After the sparse array deployment is specified, the optimization technique is applied to find the beamformer coefficients. The proposed method helps to save the computation time in the design phase, and its beamformer performance outperforms other state-of-the-art methods in several aspects.

INNV-05. TUMOR TREATING FIELDS (TTFIELDS) TREATMENT PLANNING FOR A PATIENT WITH ASTROCYTOMA IN THE SPINAL CORD

Abstract BACKGROUND The use of Tumor Treating Fields (TTFields) following resection and chemoradiation has increased survival in patients with Glioblastoma. Randomized data provide strong rationale for planning TTFields transducer array placement to maximize TTFields dose at the tumor in a patient-specific manner. Here we present a case demonstrating the use of numerical simulations for patient-specific TTFields treatment planning for a spinal tumor. METHODS Treatment planning was performed for a 48 year old patient following T10-L1 laminectomy, gross total resection, and postoperative chemoradiation for an anaplastic astrocytoma of the spinal cord. An MRI at 3 weeks following chemoradiation showed tumor recurrence. Based on the post-chemoradiation MRI, a patient-specific model was created. The model was created by modifying a realistic computational phantom of a healthy female. To mimic the laminectomy, the lamina in T10-L1 was removed, and the region assigned electric conductivity similar to that of muscle. A virtual mass was introduced into the spinal cord. Virtual transducer arrays were placed on the model at multiple positions, and delivery of TTFields simulated. The dose delivered by different transducer array layouts was calculated, and the layouts that yielded maximal dose to the tumor and spine identified. RESULTS Transducer array layouts, in which the arrays were placed on the back of the patient with one array above the tumor and one array below the tumor, yielded the highest doses at the tumor site. Such layouts yielded TTFields doses of over 3.4mW/cm3 which is well above the threshold dose of 1.1 mW/cm3 reported previously [Ballo et al Red Jour 2019]. CONCLUSIONS These data represent the first ever study on utilizing numerical simulations in order to plan treatment for a spinal tumor in a patient-specific manner. This is an important milestone in the developing a framework for TTFields dosimetry and treatment planning.

The Impact of the Electric Conductivity of Tissues on the Electric Field Intensity and Power Density during TTFields Therapy for Glioblastoma

Tumor Treating Fields (TTFields) is an FDA-approved technique used in the treatment of glioblastoma (GBM). It consists in inducing an electric field (EF) in the head in two perpendicular directions alternately using a specific device that operates at 200 kHz. Post-hoc analyses of the EF-14 clinical trial results showed that an intensity of at least 1.06 V/cm and a minimum power density (PD) of 1.15 mW/cm3 at the tumor bed can significantly affect the mitotic process of tumoral cells. Given that it is not possible to experimentally measure these quantities, computational modelling is widely used to predict treatment effectiveness. However, the uncertainties in the electric conductivity (σ) of biological tissues affect the accuracy of these predictions. The goal of this work is to investigate for which tissues the uncertainty associated with σ values leads to the highest variations in these metrics and quantify their impact. A realistic head model divided into scalp, skull, CSF and brain was used in this study. A virtual lesion was added at the right hemisphere near the ventricle. This lesion intended to represent a GBM tumor and it consisted in a necrotic region surrounded by an enhancing part. Two pairs of transducer arrays were placed on the scalp. The first was placed over the supraorbital region and at the back of the head (Anterior-Posterior or AP configuration) and the other over the left and right temporal and parietal regions (Left-Right or LR configuration). To perform the sensitivity analysis of the most significant electric parameters, an extensive literature review was performed to obtain a range of σ values for each tissue represented. The average values of the EF intensity and PD were analyzed in a volume of interest (VOI) containing the enhancing tumor plus a 3-mm-thick proximal boundary surrounding it. Given that this array layout was not optimized for this specific tumor location the AP configuration did not produce a therapeutic EF at the tumor bed and thus just the results for the LR configuration were analyzed. The highest variation in the EF intensity in the VOI was seen when changing the electric conductivity of the white matter. Decreasing it led to a maximum of 1.82 V/cm, whereas increasing it to the maximum value reported in the literature led to a minimum EF intensity of 1.14 V/cm. On the other hand, the minimum value for the PD occurred when skull’s conductivity was reduced, 1.16 mW/cm3, while the maximum was obtained when scalp’s conductivity was diminished, 2.69 mW/cm3. These results indicate that the uncertainty associated with the electric parameters of tissues might lead to significant variations in the metrics used to evaluate TTFields efficacy. Experimental measurements are necessary to determine these values with precision and thus to increase the accuracy of data obtained through computational simulations.

A Simulation-Based Method for Planning Delivery of TTFields to Brain Tumors

Tumor Treating Fields (TTFields) are alternating electric fields that inhibit tumor growth. TTFields are delivered using two pairs of transducer arrays placed on the skin. Each pair of arrays creates a field oriented along the axis between the arrays. Arrays are placed to generate two fields that are roughly orthogonal to one another. Simulation-based studies have shown that TTFields distribution within the body is heterogeneous, and depends on the location of the arrays, the patient anatomy and the location and size of the tumor. A recent study showed a connection between increased TTFields dose at the tumor bed and extended patient survival in newly diagnosed Glioblastoma (ndGBM) patients [1]. This emphasizes the need for simulation-based algorithms for patient-specific TTFields treatment planning. Here we present a novel algorithm that utilizes numerical simulations in order to maximize TTFields dose in brain tumors. The outline for our optimization algorithm is as follows: First a patient-specific computational head model is created in a semi-automatic manner from patient MRI data. Next, machine vision algorithms are used in order to define an axial slice passing above the eyes and eyebrows. To ensure transducer arrays are placed in a practical manner, only transducer array layouts in which all arrays are placed above this slice are tested. Next, a finite set of pairs of virtual transducer arrays are placed on the head model and the electric field created by each pair simulated using a finite elements method. To ensure maximal delivery of TTFields to the tumor, the arrays are placed such that the “imaginary” line connecting their centers passes through the tumor bed. A set of layouts is created by combining pairs of arrays (all possible combinations of pairs are created), and the dose delivered by the layouts calculated. The layout that maximizes TTFields dose at the tumor bed is found, and a set of small shifts and rotations is applied to the arrays in the chosen layout order eliminate overlaps between the transducers of the different arrays. The algorithm was tested on MRI data from ten Glioblastoma patients. In all cases, the algorithm converged to yield an optimal array layout that could be placed in a practical manner. Generally, the arrays of the optimal layout were located on the scalp in close proximity to the tumor. In all cases, the optimal layouts delivered average TTFields intensities above the therapeutic threshold of 1 V/cm to the tumors. The average dose delivered by the optimal layouts to the tumors were well above 1 mW/cm3, which has been associated with prolonged patient survival. We have developed a novel simulation-based method for optimizing TTFields treatment planning for brain tumors. Incorporation of such algorithms into sophisticated treatment planning systems is expected to improve the management of TTFields patients by the treating physician, ultimately improving patient outcomes.

Using Experimentally Validated Navier-Stokes CFD to Minimize Tidal Stream Turbine Power Losses Due to Wake/Turbine Interactions

Tidal stream turbines fixed on the seabed can harness the power of tides at locations where the bathymetry and/or coastal geography result in high kinetic energy levels of the flood and/or neap currents. In large turbine arrays, however, avoiding interactions between upstream turbine wakes and downstream turbine rotors may be hard or impossible, and, therefore, tidal array layouts have to be designed to minimize the power losses caused by these interactions. For the first time, using Navier-Stokes computational fluid dynamics simulations which model the turbines with generalized actuator disks, two sets of flume tank experiments of an isolated turbine and arrays of up to four turbines are analyzed in a thorough and comprehensive fashion to investigate these interactions and the power losses they induce. Very good agreement of simulations and experiments is found in most cases. The key novel finding of this study is the evidence that the flow acceleration between the wakes of two adjacent turbines can be exploited not only to increase the kinetic energy available to a turbine working further downstream in the accelerated flow corridor, but also to reduce the power losses of said turbine due to its rotor interaction with the wake produced by a fourth turbine further upstream. By making use of periodic array simulations, it is also found that there exists an optimal lateral spacing of the two adjacent turbines, which maximizes the power of the downstream turbine with respect to when the two adjacent turbines are absent or further apart. This is accomplished by trading off the amount of flow acceleration between the wakes of the lateral turbines, and the losses due to shear and mixing of the front turbine wake and the wakes of the two lateral turbines.

Comparison of Wave Energy Park Layouts by Experimental and Numerical Methods

An experimental campaign of arrays with direct-driven wave energy converters of point-absorbing type is presented. The arrays consist of six identical floats, moving in six degrees of freedom, and six rotating power take-off systems, based on the design developed at Uppsala University. The goals of the work were to study and compare the performances of three different array layouts under several regular and irregular long-crested waves, and in addition, to determine whether the numerical predictions of the best performing array layouts were confirmed by experimental data. The simulations were executed with a frequency domain model restricted to heave, which is a computationally fast approach that was merged into a genetic algorithm optimization routine and used to find optimal array configurations. The results show that good agreement between experiments and simulations is achieved when the test conditions do not induce phenomena of parametric resonance, slack line and wave breaking. Specific non-linear dynamics or extensive sway motion are not captured by the used model, and in such cases the simulation predictions are not accurate, but can nevertheless be used to get an estimate of the power output.

Editorial for the special issue on advances in forward and inverse surrogate modeling for high‐frequency design

Editorial for the special issue on advances in forward and inverse surrogate modeling for <scp>high‐frequency</scp> design

Optimization of growth performance responses of Japanese quail with different concentrations of metabolizable energy, lysine, and sulfur amino acids using Taguchi method

The present study was conducted to evaluate the effects of different concentrations of metabolizable energy (ME), Lys, and Met + Cys on the growth performance of Japanese quail breeder, hatching eggs, and production performance of their offsprings by Taguchi method. Total of 630 Japanese quails (6-wk-old) were randomly distributed between 9 experimental treatments with 5 replicates (14 quails in each cage) per treatment for 9 wk. The dietary treatments, including 3 different ME concentrations (2,700, 2,850, and 3,000 kcal/kg), 3 different concentrations of Lys (0.88, 1.00, and 1.12%), and 3 different concentrations of Met + Cys (0.65, 0.75, and 0.85%), were used in L9 (33) orthogonal array layout. Egg production, feed intake, egg weight, and feed conversion ratio were recorded and calculated biweekly. At the end of the wk 13, 14, and 15, of age of quail breeder, hatchability, and the average weight of offspring were recorded. First group of hatched chicks were raised under a standard condition with the common diet for 12 d. Results showed that quails fed the diet containing 3,000 kcal ME/kg, 1.12% Lys, and 0.85% Met + Cys had the greatest feed intake, egg production, egg weight, hatchability, and the lowest feed conversion ratio throughout the study. For the offspring, the best growth rate was also achieved by feeding the diet containing 3,000 kcal ME/kg, 1.12% Lys, and 0.85% Met + Cys to japanese quail breeders. The results of this study showed that the Taguchi method could be used successfully toestimate ME, Lys, and Met + Cys requirements of quail breeder, and their offspring.

A Novel BIPV Reconfiguration Algorithm for Maximum Power Generation under Partial Shading

The feasibility of electricity production via solar energy in the Middle East is high due to the enormous value of solar radiation. Building-integrated photovoltaics (BIPV) are systems used to utilise the unused spaces that can be installed on the façade or roof by replacing the building’s main element. However, the main problem associated with electricity production by BIPV is partial shading on the roof, which can produce multiple hot spots and disturbances to the system if the insolation values within the whole BIPV array vary. Partial shading, in this case, is observed due to the complexly shaped roof. This paper studies the partial shading effect on one of Qatar’s most recent projects (metro stations), and models the Education City station, which is a major station. The rooftop is complex, and it has many wavy shapes that can affect the BIPV system’s performance. The station is modelled using building-information modelling (BIM) software, wherein all of the station’s models are gathered and linked using BIM software to illustrate the BIPV and indicate the solar insolation distribution on the rooftop by simulating the station’s rooftop. The system is optimised for maximum yield to determine the optimal configuration and number of modules for each string using a genetic algorithm. The outcomes from the algorithm are based on clustering the solar insolation values and then applying a genetic algorithm optimisation to indicate the optimum BIPV array layout for maximum yield.

Abstract 5497: Transducer array layouts for treating head and neck cancer with TTFields

Abstract Tumor Treating Fields (TTFields) are a novel antimitotic treatment for solid tumors. TTFields utilize low frequency (1-4 V/cm) electric fields in the intermediate frequency range (100-300 kHz), and are currently FDA approved for the treatment of glioblastoma multiforme (GBM) using the Optune device. TTFields are also approved for multi pleural mesothelioma (MPM). The fields are delivered using two pairs of transducer arrays placed on different places on the patient's skin. In order for the treatment to be efficacious, placement should be performed in a manner such that the tumor receives significant dose of TTFields. An effective dose is considered to be at least 1 V/cm in the region of interest. Nevertheless, preclinical studies has shown that higher field values result in greater tumor growth inhibition. When TTFields are delivered, the field distribution is determined by a series of non-intuitive factors, such as the different electric conductivity of the different organs, making intuitive placement inaccurate. Therefore, different parts of the body require specific array layout design. Such case occurs with head and neck cancer. In this work we examined our ability to deliver TTFields to the larynx and its surroundings. Methods We used computer simulations to estimate the field distribution different layouts would provide. The simulations used a computational phantom representing a 34 years old male (DUKE 3.1, ITI'S foundation, Zurich). We placed virtual transducer arrays comprising either 13 or 9 ceramic disks were placed on the model's skin and delivery of TTFields to the model was simulated Sim4Life v4.4 (by ZMT, Zurich). 6 different array layouts were tested. In layouts 1-3, one array comprising 13-disks was placed on the model's scalp while the other 13-disks array was placed on its chest. Forcase 4 a pair of 9-disks arrays was used, one array was placed on the forehead of the model and the other on it'supper chest. In cases 5-6, we placed 9-disks arrays around the patient's neck. We then analyzed the field intensity within a region of interest (ROI) including the larynx and surrounding tissues. Results In cases 1-2 and 4, mean field intensities within the ROI were 3.29 V/cm, 3.46 V/cm and 2.6 V/cm, respectively, well above the clinical threshold of 1 V/cm. Cases 3, 5 and 6 showed to have median field of 1.41, 1.37 and 1.27 V/cm. Though still above the clinical threshold, these field intensities are significantly lower than in the other cases. This, apparently, is due to current flow through the neck muscles behind the ROI. Conclusions This study shows that it is possible to deliver TTFields at therapeutic intensities to the larynx and the surrounding tissues. Thus, TTFields may be a therapeutic option for treating head and neck tumors located in the larynx and the surrounding tissues. Citation Format: Ze'ev Bomzon, Ariel Naveh, Yissachar Abraham. Transducer array layouts for treating head and neck cancer with TTFields [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5497.

Abstract 44: TTFields dose distribution alters tumor growth patterns: An imaging-based analysis of the randomized phase 3 EF-14 trial

Abstract Introduction: The pivotal phase 3 EF-14 trial revealed extended Overall Survival (OS) and Progression Free Survival (PFS) in newly Diagnosed Glioblastoma (ndGBM) patients that received Tumor Treating Fields + chemoradiation vs. patients that received chemoradiation alone. The effect of TTFields is dose-dependent, with improved outcomes for patients who received higher doses of TTFields to the tumor bed [1]. Recent studies have also shown that TTFields influences tumor progression patterns in patients in a dose-dependent manner, with recurrence more likely to occur in regions of the brain in which field intensities are lower. This study also revealed that distal progressions are more common in ndGBM patients treated with TTFields_chemoradiation vs. patients treated with chemoradiation alone [2]. Thus it seems that a major influence of TTFields is to enhance local control of the primary lesion. Here we present an analysis testing this hypothesis by analyzing tumor growth rates in patients who participated in the EF-14 trial. Methods: Biopsy patients of the EF-14 trial who exhibited radiological progression were included in this study (treatment: N=37/60, control: N=12/29). Volumes of enhancing tumor were segmented on T1-contrast MRIs at baseline and at progression. The tumor Specific Growth Rate (SGR) was calculated as: Specific_Growth_Rate=(ln(v0)-ln(v1))/dt. Here, v0 represents tumor volume at baseline, v1 represents tumor volume at progression, and dt represents the time to progression. This equation models tumor volume as increasing exponentially over time [3]. The distribution of growth rates in the treatment and control arms were compared. The analysis was restricted to biopsy-only patients since the definition of tumor volume is ambiguous in patients that underwent resection, as a large portion of the tumor has been removed. Results: The median growth rate was lower in the treatment arm than in the control. (control: 0.14±0.12 mL/month, TTFields -0.011±0.11 mL/month, p&amp;lt;0.008 Wilcoxon rank-sum). Discussion and conclusions: This study suggests that TTFields does indeed enhance local control of the tumor, significantly inhibiting the growth rate of the primary lesion. In this context, is worth noting that standard practice is to plan placement of the transducer arrays used to deliver TTFields in order to maximize dose delivered to the tumor. Thus, the results of this study support the hypothesis that adaptive treatment planning, in which the transducer array layout is periodically changed in order to dynamically target regions in which progression is observed, may help to improve patient outcomes.

Design of a solar photovoltaic system for a Ro-Ro ship and estimation of performance analysis: A case study

Maritime transportation has a remarkable contribution to the increase of pollutant gases in the atmosphere, and adapting alternative energy systems to ship’s main power grid is an effective method to both save energy and reduce the amount of emission gases. For this reason, the contribution of solar power, which is one of the effective alternative energy sources, to the marine vessels as a result of adaptation to the ship’s power system and the environmental impacts of application is evaluated within the scope of the study. A novel approach is demonstrated for the layout of solar arrays within a Ro-Ro type marine vessel navigated between Pendik/Turkey and Trieste/Italy during 2018, and the performance of the designed system is theoretically evaluated. According to followed methodology, 7.76% of energy efficiency is carried out and 7.38% of the fuel requirement of the stated vessel is met by the designed solar system. 0.312 tons of SOx, 3.942 tons of NOx, 232.393 tons of CO2, and 0.114 tons of PM are prevented from releasing to the atmosphere. Besides, the investment of the solar system is analyzed under three different economic indicators and is found to be economically profitable to implement on the ship.

Magnetically Guided Micromanipulation of Magnetic Microrobots for Accurate Creation of Artistic Patterns in Liquid Environment.

In this paper, a magnetically guided micromanipulation method is proposed to accurately create artistic patterns with magnetic microrobots in a liquid environment for tissue engineering. A magnetically guided device is developed depend on symmetrical combination of square permanent magnets and array layout of soft magnetic wires, which changed the space distribution of magnetic field of conventional permanent magnet and generated powerful magnetic flux density and high magnetic field gradient. Furthermore, the morphological structure of the magnetic microrobot is flexibly adjusted via precise control of the volumetric flow rates inside the microfluidic device and the magnetic nanoparticles are taken along to enable its controllability by rapid magnetic response. And then, the spatial posture of the magnetic microrobot is contactless controlled by the magnetically guided manipulator and it is released under the influence of surface tension and gravity. Subsequently, the artistic fashions of the magnetic microrobots are precisely distributed via the dot-matrix magnetic flux density of the magnetically guided device. Finally, the experimental results herein demonstrate the accuracy and diversity of the pattern structures in the water and the developed method will be providing a new way for personalized functional scaffold construction.

Underwater Localization via Wideband Direction-of-Arrival Estimation Using Acoustic Arrays of Arbitrary Shape.

Underwater sensing and remote telemetry tasks necessitate the accurate geo-location of sensor data series, which often requires underwater acoustic arrays. These are ensembles of hydrophones that can be jointly operated in order to, e.g., direct acoustic energy towards a given direction, or to estimate the direction of arrival of a desired signal. When the available equipment does not provide the required level of accuracy, it may be convenient to merge multiple transceivers into a larger acoustic array, in order to achieve better processing performance. In this paper, we name such a structure an “array of opportunity” to signify the often inevitable sub-optimality of the resulting array design, e.g., a distance between nearest array elements larger than half the shortest acoustic wavelength that the array would receive. The most immediate consequence is that arrays of opportunity may be affected by spatial ambiguity, and may require additional processing to avoid large errors in wideband direction of arrival (DoA) estimation, especially as opposed to narrowband processing. We consider the design of practical algorithms to achieve accurate detections, DoA estimates, and position estimates using wideband arrays of opportunity. For this purpose, we rely jointly on DoA and rough multilateration estimates to eliminate spatial ambiguities arising from the array layout. By means of emulations that realistically reproduce underwater noise and acoustic clutter, we show that our algorithm yields accurate DoA and location estimates, and in some cases it allows arrays of opportunity to outperform properly designed arrays. For example, at a signal-to-noise ratio of –20 dB, a 15-element array of opportunity achieves lower average and median localization error (27 m and 12 m, respectively) than a 30-element array with proper element spacing (33 m and 15 m, respectively). We confirm the good accuracy of our approach via emulation results, and through a proof-of-concept lake experiment, where our algorithm applied to a 10-element array of opportunity achieves a 90th-percentile DoA estimation error of 4 and a 90th-percentile total location error of 5 m when applied to a real 10-element array of opportunity.