A Hybrid Level Set Optimization Design Method of Functionally Graded Cellular Structures Considering Connectivity

With the continuous advancement in topology optimization and additive manufacturing(AM)technology,the capability to fabricate functionally graded materials and intricate cellular structures with spatially varying microstructures has grown significantly.However,a critical challenge is encountered in the design of these structures–the absence of robust interface connections between adjacent microstructures,potentially resulting in diminished efficiency or macroscopic failure.A Hybrid Level Set Method(HLSM)is proposed,specifically designed to enhance connectivity among non-uniform microstructures,contributing to the design of functionally graded cellular structures.The HLSM introduces a pioneering algorithm for effectively blending heterogeneous microstructure interfaces.Initially,an interpolation algorithm is presented to construct transition microstructures seamlessly connected on both sides.Subsequently,the algorithm enables the morphing of non-uniform unit cells to seamlessly adapt to interconnected adjacent microstructures.The method,seamlessly integrated into a multi-scale topology optimization framework using the level set method,exhibits its efficacy through numerical examples,showcasing its prowess in optimizing 2D and 3D functionally graded materials(FGM)and multi-scale topology optimization.In essence,the pressing issue of interface connections in complex structure design is not only addressed but also a robust methodology is introduced,substantiated by numerical evidence,advancing optimization capabilities in the realm of functionally graded materials and cellular structures.

The Impact of Sea Level Rise on Roadway Design and Evacuation Routes in Delaware

As the global temperature continues to increase, the sea level continues to rise at a rapid rate that has never been seen before. This becomes an issue for many facets of life but one of the most impacted is the transportation infrastructure. Many people living in low elevation coastal areas can become trapped by flooding with no way in or out. With Delaware being a coastal state, this would affect a large portion of the population and will have detrimental effects over time if nothing is done to combat sea level rise. The issue with sea level rise in transportation is that once the roads become flooded, they become virtually unusable and detour routes would be needed. If all the roads in a coastal area were to be affected by sea level rise, the options for detours would become limited. This article looks at direct solutions to combat sea level rise and indirect solutions that would specifically help transportation infrastructure and evacuation routes in Delaware. There is not one solution that can fix every problem, so many solutions are laid out to see what is applicable to each affected area. Some solutions include defense structures that would be put close to the coast, raising the elevation of vulnerable roads throughout the state and including pumping stations to drain the water on the surface of the road. With an understanding of all these solutions around the world, the ultimate conclusion came in the form of a six-step plan that Delaware should take in order to best design against sea level rise in these coastal areas.

Design and Optimization of Dual-Winding Fault-Tolerant Permanent Magnet Motor

To improve the performance of the traditional fault-tolerant permanent magnet(PM)motor,the design and optimal schemes of dual-winding fault-tolerant permanent magnet motor(DWFT-PMM)are proposed and investigated.In order to obtain small cogging torque ripple and inhibiting the short-circuit current,the air gap surface shape of the PM and the anti short-circuits reactance parameters are designed and optimized.According to the actual design requirements of an aircraft electrical actuation system,the parameters,finite element analysis and experimental verification of the DWFT-PMM after optimal design are presented.The research results show that the optimized DWFT-PMM owns the merits of strong magnetic isolation,physics isolation,inhibiting the short circuit current,small cogging torque ripple and high fault tolerance.

Fault-Tolerant Design Techniques in ACMP Architecture

Single-chip multiprocessor (CMP) combined with the fault-loleranl(FT)techniques offers an ideal architecture to achieve high availability on the basis of sustaining highcomputing performance FT design of a single-chip multiprocessor is described, including thetechniques from hard-wart redundancy to software support and firmware strategy. The design aims atmasking the influences of errors and automatically correcting the system states.

Evolutionary Design of Fault-Tolerant Digital Circuit Based on Cartesian Genetic Programming

In many areas, reliability of the digital circuits has become the key factor to restrict circuit development. Fault-tolerant design is the commonly used method to improve the reliability of digital circuits. The current fault-tolerant design methods are based on triple modular redundancy( TMR) or multiple modular redundancy( MMR). These redundancy designs rely on the experience of the designers,and the designed circuits have poor adaptabilities to a complex environment. However, evolutionary design of digital circuits does not rely on prior knowledge. During the evolution, some novel and optimal circuit topologies can be found, and the evolved circuits can feature strong adaptive capacities. Based on Cartesian genetic programming( CGP), a novel method for designing fault-tolerant digital circuits by evolution is proposed,key steps of the evolution are introduced,influences of function sets on evolution are investigated,and as a preliminary result,an evolved full adder with high fault-tolerance is shown.

Fault-tolerant Strategies and Their Design Methods for Application Software

The key to software reliability is fault-tolerant design ofapplication software.New fault-tolerant strategies andtheir design methods for application software under vari-ous computer system are introduced.It has such advan-tages as simple hardware platform,independent fromapplication,stable reliability.lastly,some technicalproblems are discussed in details.

Research on robust fault-tolerant control for networked control system with packet dropout

A kind of networked control system with network-induced delay and packet dropout, modeled on asynchronous dynamical systems was tested, and the integrity design of the networked control system with sensors failures and actuators failures was analyzed using hybrid systems technique based on the robust fault-tolerant control theory. The parametric expression of controller is given based on the feasible solution of linear matrix inequality. The simulation results are provided on the basis of detailed theoretical analysis, which further demonstrate the validity of the proposed schema.

Fault-Tolerant Control Research for Networked Control System under Communication Constraints

Implementing a control system over a communication network induces inevitable time delays that may degrade performance and even cause instability. One of the most effective ways to reduce the negative effect of delays on the performance of networked control system (NCS) is to reduce network traffic. In this paper, adjustable deadbands are explored as a solution to reduce network traffic in NCS. A method of fault-tolerant control of networked control system is presented, which takes into account system response as well as network traffic. The integrity design for a kind of NCS with sensor failures and actuator failures is analyzed based on robust fault-tolerant control theory and information scheduling. After detailed theoretical analysis, the paper also provides the simulation results, which further validate the proposed scheme.

LEVEL SET METHOD FOR TOPOLOGICAL OPTIMIZATION APPLYING TO STRUCTURE, MECHANISM AND MATERIAL DESIGNS

Based on a level set model, a topology optimization method has been suggestedrecently. It uses a level set to express the moving structural boundary, which can flexibly handlecomplex topological changes. By combining vector level set models with gradient projectiontechnology, the level set method for topological optimization is extended to a topologicaloptimization problem with multi-constraints, multi-materials and multi-load cases. Meanwhile, anappropriate nonlinear speed, mapping is established in the tangential space of the activeconstraints for a fast convergence. Then the method is applied to structure designs, mechanism andmaterial designs by a number of benchmark examples. Finally, in order to further improvecomputational efficiency and overcome the difficulty that the level set method cannot generate newmaterial interfaces during the optimization process, the topological derivative analysis isincorporated into the level set method for topological optimization, and a topological derivativeand level set algorithm for topological optimization is proposed.

A method to calculate design tide levels on the basis of numerical model of tidal current and its application

In order to determine the design tide levels in the areas without measured tide level data, especially in the areas where it is difficult to measure tidal levels, a calculation method based on a numerical model of tidal current is proposed. The essentials of the method are described, and its application is illustrated with an example. The results of the application show that the design tide levels calculated by the method are close to those determined by long-time measured tide level data, and its calculation precision is high, so it is feasible to use the method to determine the design tide levels in the areas.

System-on-Chip Design Using High-Level Synthesis Tools

This paper addresses the challenges of System-on-Chip designs using High-Level Synthesis (HLS). HLS tools convert algorithms designed in C into hardware modules. This approach is a practical choice for developing complex applications. Nevertheless, certain hardware considerations are required when writing C applications for HLS tools. Hence, in order to demonstrate the fundamental hardware design concepts, a case studyis presented. Fast Fourier Transform (FFT) implementation in ANSI C is examined in order to explore the important design issues such as concurrency, data recurrences and memory accesses that need to be resolved before generating the hardware using HLS tools. There are additional language constraints that need to be addressed including use of pointers, recursion and floating point types.

Design on AM-OLED display control ASIC with high gray scale levels

The paper puts forward a method on controlling the AM-OLED panel to display image with high gray scale levels. It also gives an ASIC design sample to implement this method. A twenty sub-fields scan scheme has been taken into use in the chip to display 256 gray scale levels on a QVGA resolution AM-OLED display screen. The functions of image scaling and rotating have also been implemented for multiply application. The simulation and chip test result show that the chip design has met the design requirements.

FUZZY OPTIMIZATION MODEL OF MAINTENANCE DESIGN FOR PRODUCT LEVEL REUSE

Most used products must be maintained before they are reused. The modelingmethod for maintenance design of product level reuse based on quality function deployment ispresented. A fuzzy linear optimization model is developed under financial uncertainty. Objective ofthe model is to maximize improvement rate of customer satisfaction level. Maintenance cost constrainis fuzzy. The algorithm for solution to the model is given. Its optimized results not only giveattention to satisfaction degree of cost constraint, but also maximize objective value. Anillustrative example involved water bump reuse is studied and the results show that the proposedmodel can effectively help maintenance planner determine the better design scheme.

A LEVEL SET METHOD FOR MICROSTRUCTURE DESIGN OF COMPOSITE MATERIALS

Based on a level set model and the homogenization theory, an optimization al- gorithm for ?nding the optimal con?guration of the microstructure with speci?ed properties is proposed, which extends current research on the level set method for structure topology opti- mization. The method proposed employs a level set model to implicitly describe the material interfaces of the microstructure and a Hamilton-Jacobi equation to continuously evolve the ma- terial interfaces until an optimal design is achieved. Meanwhile, the moving velocities of level set are obtained by conducting sensitivity analysis and gradient projection. Besides, how to handle the violated constraints is also discussed in the level set method for topological optimization, and a return-mapping algorithm is constructed. Numerical examples show that the method exhibits outstanding ?exibility of handling topological changes and ?delity of material interface represen- tation as compared with other conventional methods in literatures.

A New Rational-based Optimal Design Strategy of Ship Structure Based on Multi-level Analysis and Super-element Modeling Method

A new multi-level analysis method of introducing the super-element modeling method, derived from the multi-level analysis method first proposed by O. F. Hughes, has been proposed in this paper to solve the problem of high time cost in adopting a rational-based optimal design method for ship structural design. Furthermore,the method was verified by its effective application in optimization of the mid-ship section of a container ship. A full 3-D FEM model of a ship,suffering static and quasi-static loads, was used as the analyzing object for evaluating the structural performance of the mid-ship module, including static strength and buckling performance. Research results reveal that this new method could substantially reduce the computational cost of the rational-based optimization problem without decreasing its accuracy, which increases the feasibility and economic efficiency of using a rational-based optimal design method in ship structural design.

Multidisciplinary Design Optimization of A Human Occupied Vehicle Based on Bi-Level Integrated System Collaborative Optimization

The design of Human Occupied Vehicle （HOV） is a typical multidisciplinary problem, but heavily dependent on the experience of naval architects at present engineering design. In order to relieve the experience dependence and improve the design, a new Multidisciplinary Design Optimization （MDO） method ＂Bi-Level Integrated System Collaborative Optimization （BLISCO）＂ is applied to the conceptual design of an HOV, which consists of hull module, resistance module, energy module, structure module, weight module, and the stability module. This design problem is defined by 21 design variables and 23 constraints, and its objective is to maximize the ratio of payload to weight. The results show that the general performance of the HOV can be greatly improved by BLISCO.

Toward a Multi-Hop, Multi-Path Fault-Tolerant and Load Balancing Hierarchical Routing Protocol for Wireless Sensor Network

This paper describes a novel energy-aware multi-hop cluster-based fault-tolerant load balancing hierarchical routing protocol for a self-organizing wireless sensor network (WSN), which takes into account the broadcast nature of radio. The main idea is using hierarchical fuzzy soft clusters enabling non-exclusive overlapping clusters, thus allowing partial multiple membership of a node to more than one cluster, whereby for each cluster the clusterhead (CH) takes in charge intra-cluster issues of aggregating the information from nodes members, and then collaborate and coordinate with its related overlapping area heads (OAHs), which are elected heuristically to ensure inter-clusters communication. This communication is implemented using an extended version of time-division multiple access (TDMA) allowing the allocation of several slots for a given node, and alternating the role of the clusterhead and its associated overlapping area heads. Each cluster head relays information to overlapping area heads which in turn each relays it to other associated cluster heads in related clusters, thus the information propagates gradually until it reaches the sink in a multi-hop fashion.

Research on Flood Control Design Based on Joint Distribution of Flood Levels and Flood Peak Discharges

The return level of the joint distribution of flood levels and flood peak discharges was analyzed by Archimedean Gumbel-Hougaard copula and Kendall distribution functions.Using the annual maximum level(H)and discharge(Q)of flood peak at Boluo Hydrologic Station in the Dongjiang River in last 56 years,the"OR"return period,"AND"return period and Kendall return period of their joint distribution and the most likely design flood value were calculated.The main conclusions of this study can be summarized as follows:the Kendall return period can more accurately reflect the risk rate of the combination of flood elements,relative to"OR"return period and"AND"return period.The design value of univariate flood element based on the current specification can meet the design standard.While the design value calculated according to"OR"return period was on the high side,and the design value calculated by the"AND"return period was on low side.Based on the principle of maximum probability,the calculated design value of Kendall return period under the different combinations of flood peak discharge and water level can provide new options for flood control project safety and risk management.

Design of Low Power Level Shifter Circuit with Sleep Transistor Using MultiSupply Voltage Scheme

New low-power Level Shifter (LS) circuit is designed by using sleep transistor with Multi Threshold CMOS (MTCMOS) technique for robust logic voltage shifting from sub-threshold to above- threshold domain. MultiSupply Voltage Design (MSVD) technique is mainly used for energy and speed in modern system-on-chip. In MSVD, level shifters are required to allow different voltage supply to shift from the lower power supply voltage to the higher power supply voltage. This new low-power level shifter circuit is also used for fast response and low leakage power consumption. This low leakage power consumption can be achieved through insertion of sleep transistor and proper transistors sizing. The proposed design efficiently converts 100 mv input signal into 1 v output signal and achieves the power of 2.56 nW by using 90 nm technology.