A Survey of Structural Optimization in Mechanical Product Development

2005 ◽  
Vol 5 (3) ◽  
pp. 214-226 ◽  
Author(s):  
Kazuhiro Saitou ◽  
Kazuhiro Izui ◽  
Shinji Nishiwaki ◽  
Panos Papalambros
Keyword(s):  
Product Development ◽  
Structural Optimization ◽  
Numerical Optimization ◽  
High Performance ◽  
Design Tool ◽  
Open Problems ◽  
Research Issues ◽  
The Past ◽  
Widespread Availability ◽  
Geometry Parameterization

The widespread availability of affordable high-performance personal computers and commercial software has prompted the integration of structural analyses with numerical optimization, reducing the need for design iterations by human designers. Despite its acceptance as a design tool, however, structural optimization seems yet to gain mainstream popularity in industry. To remedy this situation, this paper reviews past literatures on structural optimization with emphasis on their relation to mechanical product development, and discusses open research issues that would further enhance the industry acceptance of structural optimization. The past literatures are categorized based on their major research focuses: geometry parameterization, approximation methods, optimization algorithms, and the integration with nonstructural issues. Open problems in each category and anticipated future trends briefly are discussed.

scholarly journals High-performance computing environment: a review of twenty years of experiments in China

2016 ◽  
Vol 3 (1) ◽  
pp. 36-48 ◽  
Author(s):  
Zhiwei Xu ◽  
Xuebin Chi ◽  
Nong Xiao
Keyword(s):  
High Performance Computing ◽  
High Performance ◽  
The Internet ◽  
Computing Environment ◽  
Open Problems ◽  
Loosely Coupled ◽  
The Past ◽  
Important Open Problem ◽  
Computing Environments ◽  
Performance Computing

Abstract A high-performance computing environment, also known as a supercomputing environment, e-Science environment or cyberinfrastructure, is a crucial system that connects users’ applications to supercomputers, and provides usability, efficiency, sharing, and collaboration capabilities. This review presents important lessons drawn from China's nationwide efforts to build and use a high-performance computing environment over the past 20 years (1995–2015), including three observations and two open problems. We present evidence that such an environment helps to grow China's nationwide supercomputing ecosystem by orders of magnitude, where a loosely coupled architecture accommodates diversity. An important open problem is why technology for global networked supercomputing has not yet become as widespread as the Internet or Web. In the next 20 years, high-performance computing environments will need to provide zettaflops computing capability and 10 000 times better energy efficiency, and support seamless human-cyber-physical ternary computing.

Flexural design of precast, prestressed ultra-high-performance concrete members

PCI Journal ◽  
2020 ◽  
Vol 65 (6) ◽  
pp. 35-61
Author(s):  
Chungwook Sim ◽  
Maher Tadros ◽  
David Gee ◽  
Micheal Asaad
Keyword(s):  
Prestressed Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Limit State ◽  
Design Guidelines ◽  
Design Tool ◽  
Supplementary Cementitious Materials ◽  
Ultra High Performance Concrete ◽  
Concrete Members ◽  
Cylinder Strength

Ultra-high-performance concrete (UHPC) is a special concrete mixture with outstanding mechanical and durability characteristics. It is a mixture of portland cement, supplementary cementitious materials, sand, and high-strength, high-aspect-ratio microfibers. In this paper, the authors propose flexural design guidelines for precast, prestressed concrete members made with concrete mixtures developed by precasters to meet minimum specific characteristics qualifying it to be called PCI-UHPC. Minimum specified cylinder strength is 10 ksi (69 MPa) at prestress release and 18 ksi (124 MPa) at the time the member is placed in service, typically 28 days. Minimum flexural cracking and tensile strengths of 1.5 and 2 ksi (10 and 14 MPa), respectively, according to ASTM C1609 testing specifications are required. In addition, strain-hardening and ductility requirements are specified. Tensile properties are shown to be more important for structural optimization than cylinder strength. Both building and bridge products are considered because the paper is focused on capacity rather than demand. Both service limit state and strength limit state are covered. When the contribution of fibers to capacity should be included and when they may be ignored is shown. It is further shown that the traditional equivalent rectangular stress block in compression can still be used to produce satisfactory results in prestressed concrete members. A spreadsheet workbook is offered online as a design tool. It is valid for multilayers of concrete of different strengths, rows of reinforcing bars of different grades, and prestressing strands. It produces moment-curvature diagrams and flexural capacity at ultimate strain. A fully worked-out example of a 250 ft (76.2 m) span decked I-beam of optimized shape is given.

Performance Management Transformation

2020 ◽  
Keyword(s):  
Organizational Performance ◽  
Performance Management ◽  
High Performance ◽  
Best Practice ◽  
Call To Action ◽  
Daily Work ◽  
The Past ◽  
Great Debate ◽  
The Subject ◽  
New Research

No other talent process has been the subject of such great debate and emotion as performance management (PM). For decades, different strategies have been tried to improve PM processes, yielding an endless cycle of reform to capture the next “flavor-of-the-day” PM trend. The past 5 years, however, have brought novel thinking that is different from past trends. Companies are reducing their formal processes, driving performance-based cultures, and embedding effective PM behavior into daily work rather than relying on annual reviews to drive these. Through case studies provided from leading organizations, this book illustrates the range of PM processes that companies are using today. These show a shift away from adopting someone else’s best practice; instead, companies are designing bespoke PM processes that fit their specific strategy, climate, and needs. Leading PM thought leaders offer their views about the state of PM today, what we have learned and where we need to focus future efforts, including provocative new research that shows what matters most in driving high performance. This book is a call to action for talent management professionals to go beyond traditional best practice and provide thought leadership in designing PM processes and systems that will enhance both individual and organizational performance.

Fused Ambipolar Aza-isoindigos with NIR absorption

2021 ◽  
Author(s):  
Liping Yao ◽  
Danlei Zhu ◽  
Hailiang Liao ◽  
Sheik Haseena ◽  
Mahesh kumar Ravva ◽  
...  
Keyword(s):  
Organic Semiconductors ◽  
High Performance ◽  
Low Cost ◽  
Light Weight ◽  
The Past ◽  
Pi Conjugated ◽  
Nir Absorption ◽  
Conjugated Organic Semiconductors

Due to their advantages of low-cost, light-weight, and mechanical flexibility, much attention has been focused on pi-conjugated organic semiconductors. In the past decade, although many materials with high performance has...

scholarly journals Analysis of the Mycosporine-Like Amino Acid (MAA) Pattern of the Salt Marsh Red Alga Bostrychia scorpioides

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 321
Author(s):  
Maria Orfanoudaki ◽  
Anja Hartmann ◽  
Julia Mayr ◽  
Félix L. Figueroa ◽  
Julia Vega ◽  
...  
Keyword(s):  
Amino Acids ◽  
High Performance Liquid Chromatography ◽  
High Performance ◽  
Red Alga ◽  
Array Detector ◽  
Diode Array ◽  
Diode Array Detector ◽  
The Past ◽  
Specific Species

This study presents the validation of a high-performance liquid chromatography diode array detector (HPLC-DAD) method for the determination of different mycosporine-like amino acids (MAAs) in the red alga Bostrychia scorpioides. The investigated MAAs, named bostrychines, have only been found in this specific species so far. The developed HPLC-DAD method was successfully applied for the quantification of the major MAAs in Bostrychia scorpioides extracts, collected from four different countries in Europe showing only minor differences between the investigated samples. In the past, several Bostrychia spp. have been reported to include cryptic species, and in some cases such as B. calliptera, B. simpliciuscula, and B. moritziana, the polyphyly was supported by differences in their MAA composition. The uniformity in the MAA composition of the investigated B. scorpioides samples is in agreement with the reported monophyly of this Bostrychia sp.

A recent overview on the porphyrin-based π-extended small molecules as donors and acceptors for high-performance organic solar cells

2021 ◽  
Author(s):  
Venkatesh Piradi ◽  
Feng Yan ◽  
Xunjin Zhu ◽  
Wai-Yeung Raymond Wong
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Small Molecules ◽  
Organic Solar Cells ◽  
High Performance ◽  
Cost Effective ◽  
Effective Alternative ◽  
The Past ◽  
Cost Effective Alternative ◽  
Silicon Based

Organic solar cells (OSCs) have been considered as a promising cost-effective alternative to silicon-based solar cell counterparts due to their lightweight, mechanical flexibility, and easy fabrication features. Over the past...

scholarly journals Design aspects of (super)hydrophobic mesh based oil-collecting device with improved efficiency

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Weikang Xu ◽  
Zhentao Zhang ◽  
Xiaomei Cai ◽  
Yazhen Hong ◽  
Tianliang Lin ◽  
...  
Keyword(s):  
3D Printing ◽  
Water Surface ◽  
High Performance ◽  
Oil Spills ◽  
Real Life ◽  
Oily Wastewater ◽  
Coating Materials ◽  
The Past ◽  
Oil Storage ◽  
Future Success

AbstractEffective treatment of frequent oil spills and endless discharged oily wastewater is crucial for the ecosystem and human health. In the past two decades, the collection of oil from water surface has been widely studied through the simple fabrication of superhydrophobic meshes with various coating materials, but little attention is paid to the design aspects of the meshes based oil-collecting device and practical oil collection. Here, 3D-printing devices with different configurations of (super)hydrophobic meshes, circular truncated cone (CTC), cylinder and inverted CTC, and the same inverted cone-shaped structure (below the meshes for temporary oil storage) are investigated. Results demonstrate that the CTC meshes based device especially for an oblate one not only shows higher stability and discharge of the collected oils than previous reports, but also allows floating oils to enter the (super)hydrophobic mesh faster. We anticipate that future success in developing high-performance (super)hydrophobic meshes and the further optimization of the CTC mesh-based device parameters will make our proposed device more practical for the treatment of real-life oil spills.

Hierarchical Reinforcement Learning

2021 ◽  
Vol 54 (5) ◽  
pp. 1-35
Author(s):  
Shubham Pateria ◽  
Budhitama Subagdja ◽  
Ah-hwee Tan ◽  
Chai Quek
Keyword(s):  
Reinforcement Learning ◽  
Future Research ◽  
Comprehensive Overview ◽  
Open Problems ◽  
Practical Applications ◽  
Hierarchical Reinforcement Learning ◽  
The Past ◽  
Agent Learning ◽  
Multi Agent ◽  
Supplementary Material

Hierarchical Reinforcement Learning (HRL) enables autonomous decomposition of challenging long-horizon decision-making tasks into simpler subtasks. During the past years, the landscape of HRL research has grown profoundly, resulting in copious approaches. A comprehensive overview of this vast landscape is necessary to study HRL in an organized manner. We provide a survey of the diverse HRL approaches concerning the challenges of learning hierarchical policies, subtask discovery, transfer learning, and multi-agent learning using HRL. The survey is presented according to a novel taxonomy of the approaches. Based on the survey, a set of important open problems is proposed to motivate the future research in HRL. Furthermore, we outline a few suitable task domains for evaluating the HRL approaches and a few interesting examples of the practical applications of HRL in the Supplementary Material.

FPGA implementation and image encryption application of a new PRNG based on a memristive Hopfield neural network with a special activation gradient

2021 ◽  
Author(s):  
Fei Yu ◽  
Zinan Zhang ◽  
Hui Shen ◽  
Yuanyuan Huang ◽  
Shuo Cai ◽  
...  
Keyword(s):  
Neural Network ◽  
Image Encryption ◽  
High Performance ◽  
Random Sequence ◽  
Random Number Generator ◽  
Security Analysis ◽  
Hopfield Neural Network ◽  
Data Encryption ◽  
Design Tool ◽  
Processing Unit

Abstract In this paper, a memristive Hopfield neural network with a special activation gradient (MHNN) is proposed by adding a suitable memristor to the Hopfield neural network (HNN) with a special activation gradient. The MHNN is simulated and dynamic analyzed, and implemented on FPGA. Then, a new pseudo-random number generator (PRNG) based on MHNN is proposed. The post-processing unit of the PRNG is composed of nonlinear post-processor and XOR calculator, which effectively ensures the randomness of PRNG. The experiments in this paper comply with the IEEE 754-1985 high precision 32-bit floating point standard and are done on the Vivado design tool using a Xilinx XC7Z020CLG400-2 FPGA chip and the Verilog-HDL hardware programming language. The random sequence generated by the PRNG proposed in this paper has passed the NIST SP800-22 test suite and security analysis, proving its randomness and high performance. Finally, an image encryption system based on PRNG is proposed and implemented on FPGA, which proves the value of the image encryption system in the field of data encryption connected to the Internet of Things (IoT).

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