Acoustic Beamforming Array Design Methods Over Irregular Shaped Areas

2021 ◽  
Vol 143 (3) ◽  
Author(s):  
Elias J. G. Arcondoulis ◽  
Yu Liu
Keyword(s):  
Reduction Method ◽  
Design Method ◽  
Logarithmic Spiral ◽  
Design Methods ◽  
Superior Performance ◽  
Full Potential ◽  
Sidelobe Level ◽  
Array Design ◽  
Spiral Array ◽  
Array Aperture

Abstract Acoustic beamforming array design methods are typically suited for circular and rectangular areas. A comparison of three array design methods is presented in this paper over irregular shaped areas, including L-shapes and arches. Partial-logarithmic spiral arrays that possess their geometric center either at the origin of the array area or the centroid of the irregular shaped area are compared against randomized array designs based on maximum sidelobe level (MSL) parameters and arrays generated using a recently published array design method named the adaptive array reduction method (AARM). In the AARM, a large array is reduced to a smaller array by seeking the removed microphone that possesses the minimum value of the MSL, the main lobe width (MLW), and a lobe distortion term. The AARM is also tested in two practical cases against a partial spiral array design used at the NASA Langley low-turbulence pressure tunnel and a hypothetical rectangular wall case. In both cases, the AARM showed superior performance to the logarithmic spiral arrays in all cases based on MSL and MLW criteria. Of the three methods compared, the AARM best utilizes the full potential array aperture of an irregular area and therefore produces the best MSL, MLW, and lobe distortion values.

scholarly journals An optimizing nested MIMO array with hole-free difference coarray

2018 ◽  
Vol 232 ◽  
pp. 01055
Author(s):  
Qiaoge Liu ◽  
Buhong Wang ◽  
Xia Li ◽  
Jiwei Tian ◽  
Tianhao Cheng ◽  
...  
Keyword(s):  
Design Method ◽  
Multiple Input Multiple Output ◽  
Difference Set ◽  
Mimo Radar ◽  
Array Element ◽  
Estimation Accuracy ◽  
Array Design ◽  
Closed Expression ◽  
Multiple Input ◽  
Array Aperture

According to the newly proposed nested MIMO (Multiple-Input Multiple-Input Multiple Output Multiple Array) array design method, we propose to replace the traditional nested array into an optimizing nested array, ie, to optimizing nested MIMO array design. It not only retains the original advantage of nested MIMO array design closed expression with array element position and degree of freedom(DOF), but also greatly improves the array aperture and DOF. Optimizing nested MIMO array firstly uses the optimizing nested array as the transmitting and receiving arrays, and then make the difference set processing for the coarray of MIMO array (coarray, CA). By properly designing the array spacing of the transmitting and receiving arrays, we can obtain a non-porous difference array. When the total number of array elements is given, by analyzing the characteristics of the array structure, the best array element number of the transmitting and receiving arrays can be obtained. Simulation experiments show that compared with the nested MIMO array design, the proposed method can effectively expand the array aperture, increase the DOF, and increase the DOA estimation accuracy of the MIMO radar without increasing the number of actual array elements.

SUPERPAVE VERSUS CONVENTIONAL TECHNIQUES FOR DESIGNING NORMAL AND MODIFIED ASPHALT MIXES

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Safwan Khedr ◽  
Maram Saudy
Keyword(s):  
Design Method ◽  
Design Procedure ◽  
Design Methods ◽  
Mix Design ◽  
Superior Performance ◽  
Asphalt Pavements ◽  
Surface Layers ◽  
Asphalt Mixes ◽  
Modified Asphalt ◽  
Sbs Modified Asphalt

Due to the empirical nature and drawbacks of the conventional procedures, the Strategic Highway Research Program (SHARP) has developed a Superior Performance Asphalt Pavements (SUPERPAVE) mix design procedure. The main objective of this research is to study the applicability of the Superpave in Egypt. This is done by studying aggregate characteristics using both the Superpave and the conventional techniques, investigating the normal (virgin) and SBS modified asphalt characteristics using Superpave, and designing asphalt mixtures comprised of the characterized materials using both the Superpave and the conventional Marshall design methods. Results indicate that Superpave is applicable to Egyptian aggregate with a more restrictive supervision of crushing aggregates and gradations (some gradations may need modifications). Mix design results indicated two main findings; first, most optimum asphalt contents (OAC) determined by the Superpave mix design method are consistently less than OAC determined by the Marshall Mix design method. Second, modified asphalt mixes result in less OAC than normal asphalt mixes according to both Marshall and Superpave mix design methods for both binder and surface layers.

scholarly journals A Phase-Coded Sequence Design Method for Active Sonar

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4659
Author(s):  
Chengyu Guan ◽  
Zemin Zhou ◽  
Xinwu Zeng
Keyword(s):  
Matched Filter ◽  
Design Method ◽  
Design Methods ◽  
Time Lags ◽  
Specific Time ◽  
Sidelobe Level ◽  
Sequence Design ◽  
Active Sonar ◽  
Filter Performance ◽  
Periodic Autocorrelation

Phase-coded sequences are widely studied as the transmitted signals of active sonars. Recently, several design methods have been developed to generate phased-coded sequences satisfying specific aperiodic or periodic autocorrelation sidelobe level metrics. In this paper, based on the majorization–minimization strategy and the squared iterative acceleration scheme, we propose a method to generate sequences with the periodic weighted integrated sidelobe level metric. Numerical simulations illustrate that the proposed method can effectively suppress the periodic autocorrelation sidelobe levels in specific time lags. Compared with other sequence design methods satisfying the periodic weighted integrated sidelobe level metric, our method improves the computational efficiency significantly. In addition, the proposed sequence demonstrates better matched filter performance in specific range intervals compared with its counterpart. The results suggest that the method could be applied as a valid and real-time design method for transmitted signals of active sonars.

An Update on Improved Flange Design Methods

2007 ◽  
Author(s):  
Warren Brown
Keyword(s):  
Design Method ◽  
Design Methods ◽  
Project Development ◽  
Design Improvement ◽  
Panel Session ◽  
Improved Methods ◽  
Made In

This paper details further progress made in the PVRC project “Development of Improved Flange Design Method for the ASME VIII, Div.2 Rewrite Project” presented during the panel session on flange design at the 2006 PVP conference in Vancouver. The major areas of flange design improvement indicated by that project are examined and the suggested solutions for implementing the improved methods into the Code are discussed. Further analysis on aspects such as gasket creep and the use of leakage-based design has been conducted. Shortcomings in the proposed ASME flange design method (ASME BFJ) and current CEN flange design methods (EN-1591) are highlighted and methods for resolution of these issues are suggested.

Impact of Secondary Flow on the Accuracy of Simplified Design Methods for Steam Turbine Stages

2012 ◽  
Author(s):  
Jan Schumann ◽  
Ulrich Harbecke ◽  
Daniel Sahnen ◽  
Thomas Polklas ◽  
Peter Jeschke ◽  
...  
Keyword(s):  
Secondary Flow ◽  
Steam Turbine ◽  
Design Process ◽  
Design Method ◽  
Computing Time ◽  
Leading Edge ◽  
Design Methods ◽  
Preliminary Design ◽  
Line Design ◽  
Radial Equilibrium

The subject of the presented paper is the validation of a design method for HP and IP steam turbine stages. Common design processes have been operating with simplified design methods in order to quickly obtain feasible stage designs. Therefore, inaccuracies due to assumptions in the underlying methods have to be accepted. The focus of this work is to quantify the inaccuracy of a simplified design method compared to 3D Computational Fluid Dynamics (CFD) simulations. Short computing time is very convenient in preliminary design; therefore, common design methods work with a large degree of simplification. The origin of the presented analysis is a mean line design process, dealing with repeating stage conditions. Two features of the preliminary design are the stage efficiency, based on loss correlations, and the mechanical strength, obtained by using the beam theory. Due to these simplifications, only a few input parameters are necessary to define the primal stage geometry and hence, the optimal design can easily be found. In addition, by using an implemented law to take the radial equilibrium into account, the appropriate twist of the blading can be defined. However, in comparison to the real radial distribution of flow angles, this method implies inaccuracies, especially in regions of secondary flow. In these regions, twisted blades, developed by using the simplified radial equilibrium, will be exposed to a three-dimensional flow, which is not considered in the design process. The analyzed design cases show that discrepancies at the hub and shroud section do exist, but have minor effects. Even the shroud section, with its thinner leading-edge, is not vulnerable to these unanticipated flow angles.

Design of Cooling Towers by the Effectiveness-NTU Method

1989 ◽  
Vol 111 (4) ◽  
pp. 837-843 ◽  
Author(s):  
H. Jaber ◽  
R. L. Webb
Keyword(s):  
Heat Exchanger ◽  
Cooling Tower ◽  
Design Method ◽  
Design Methods ◽  
Parallel Flow ◽  
Basic Method ◽  
Cooling Towers ◽  
Flow Configuration ◽  
Heat Exchanger Design

This paper develops the effectiveness-NTU design method for cooling towers. The definitions for effectiveness and NTU are totally consistent with the fundamental definitions used in heat exchanger design. Sample calculations are presented for counter and crossflow cooling towers. Using the proper definitions, a person competent in heat exchanger design can easily use the same basic method to design a cooling tower of counter, cross, or parallel flow configuration. The problems associated with the curvature of the saturated air enthalpy line are also treated. A “one-increment” design ignores the effect of this curvature. Increased precision can be obtained by dividing the cooling range into two or more increments. The standard effectiveness-NTU method is then used for each of the increments. Calculations are presented to define the error associated with different numbers of increments. This defines the number of increments required to attain a desired degree of precision. The authors also summarize the LMED method introduced by Berman, and show that this is totally consistent with the effectiveness-NTU method. Hence, using proper and consistent terms, heat exchanger designers are shown how to use either the standard LMED or effectiveness-NTU design methods to design cooling towers.

A Systematic Design Selection Methodology for System-Optimal Compliant Actuation

Robotica ◽  
2018 ◽  
Vol 37 (4) ◽  
pp. 656-674 ◽  
Author(s):  
Abdullah Kamadan ◽  
Gullu Kiziltas ◽  
Volkan Patoglu
Keyword(s):  
Knee Prosthesis ◽  
Design Method ◽  
Real Life ◽  
Direct Consequence ◽  
System Level ◽  
Full Potential ◽  
System Optimal ◽  
Compliant Actuation ◽  
Design Selection ◽  
Selection Methodology

SummaryThis work presents a systematic design selection methodology that utilizes a co-design strategy for system-level optimization of compliantly actuated robots that are known for their advantages over robotic systems driven by rigid actuators. The introduced methodology facilitates a decision-making strategy that is instrumental in making selections among system-optimal robot designs actuated by various degrees of variable or fixed compliance. While the simultaneous co-design method that is utilized throughout guarantees systems performing at their full potential, a homotopy technique is used to maintain integrity via generation of a continuum of robot designs actuated with varying degrees of variable and fixed compliance. Fairness of the selection methodology is ensured via utilization of common underlying (variable) compliant actuation principle and dynamical task requirements throughout the generated system designs. The direct consequence of the developed methodology is that it allows robot designers make informed selections among a variety of systems which are guaranteed to perform at their best. Applicability of the introduced methodology has been validated using a case study for system-optimal design of an active knee prosthesis that is driven by a mechanically adjustable compliance and controllable equilibrium position actuator (MACCEPA) under a periodic/real-life dynamical task.

scholarly journals Optimal Unimodular Sequences Design Method for Active Sensing Systems

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Ze Li ◽  
Ping Li ◽  
Xinhong Hao ◽  
Xiaopeng Yan
Keyword(s):  
Optimization Problems ◽  
Design Method ◽  
Correlation Coefficients ◽  
Continuous Phase ◽  
Active Sensing ◽  
Sidelobe Level ◽  
One Dimensional ◽  
Sensing Systems ◽  
Practical Engineering ◽  
Dimensional Optimization

In active sensing systems, unimodular sequences with low autocorrelation sidelobes are widely adopted as modulation sequences to improve the distance resolution and antijamming performance. In this paper, in order to meet the requirements of specific practical engineering applications such as suppressing certain correlation coefficients and finite phase, we propose a new algorithm to design both continuous phase and finite phase unimodular sequences with a low periodic weighted integrated sidelobe level (WISL). With the help of the transformation matrix, such an algorithm decomposes the N-dimensional optimization problem into N one-dimensional optimization problems and then uses the iterative method to search the optimal solutions of the N one-dimensional optimization problems directly. Numerical experiments demonstrate the effectiveness and the convergence property of the proposed algorithm.

Using “Why and How” to Tap Into Novice Designers’ Method Selection Mindset

2018 ◽  
Author(s):  
Danielle Poreh ◽  
Euiyoung Kim ◽  
Varna Vasudevan ◽  
Alice Agogino
Keyword(s):  
Design Method ◽  
Deep Understanding ◽  
Design Methods ◽  
University Of California ◽  
Teaching Material ◽  
Human Centered Design ◽  
Method Selection ◽  
Knowledge Platform ◽  
Selection Methodology ◽  
The University

Despite the growing utilization of human-centered design, both in academia and industry, there is lack of pedagogical materials that support context-based design method selection. When used properly, design methods are linked to successful outcomes in the design process, but with hundreds of design methods to select from, knowing when and how to use a particular method is challenging. Selecting the appropriate design method requires a deep understanding of the project context. Cultivating a selection methodology that is more contextually aware, equips students with the tools to apply the most appropriate methods to their future academic and industry projects. Using theDesignExchange knowledge platform as a teaching material, we discuss a summer design course at the University of California at Berkeley that encourages students to choose design methods rather than the instructors giving a set list. The findings illustrate that when given the task to select a method, students exhibit contextually-aware method selection mindsets.

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