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Through implementing the equal-strength analysis based on unified strength theory, strength calculation formulas of two-and three-layer prestressed combined dies for cold extrusion were derived in this investigation. Two parameters were included in the suggested strength expression, parameter α presenting/considering the difference between material tensile and compressive properties, and...
This paper presents numerical studies on thermal performance of LED filament light bulbs with different bulb sizes, phosphor diameters, and phosphor shapes. A quarter of numerical model of LED filament light bulbs was built to analyze the temperature field, velocity field and distributions for convective heat flux coefficient on the filament surface. The effects of bulb sizes, phosphor diameters and...
Molecular dynamics (MD) is a computer simulation method of studying physical movements of atoms and molecules that provide detailed microscopic sampling on molecular scale. With the continuous efforts and improvements, MD simulation gained popularity in materials science, biochemistry and biophysics with various application areas and expanding data scale. Assisted Model Building with Energy Refinement...
Traditional differential evolution (DE) algorithm has a tendency to suffer from premature convergence. In this paper, we proposed an improved DE based on dynamic mutation operator and opposition learning strategy. These mechanisms can expand the search area and is helpful to balance exploration and exploitation of DE. Numerical experiments demonstrate that our algorithm is effective.
The parameter establishment of differential evolution algorithm (DE) is generally determined by the experience selection method, whose shortcomings include the massive operational parameters, the difficulty in obtaining the best parameter combination, and further obstacle to improve the optimization ability of the algorithm to a great extent. The article introduces the uniform design method of differential...
To balance the explore and exploit, we combine two algorithms, Central Force Optimization (CFO) and Gravitational Search Algorithm (GSA), and propose a multi-subgroup hierarchical hybrid of CFO and GSA (HCFO-GSA). This hybrid algorithm has a hierarchical structure: base level is a series of subgroups of CFO, and the top level comprises all elite individuals with entire subgroups. The performances...
This manuscript proposes a new approach to optimize the integration time of Geo-SAR. Due to beam-scanning velocity and Doppler parameters change intensively along with time, the integration time is quite different when elevation angle, latitude argument, squint angle and satellite attitude change. To avoid the system design and data processing difficulties, the integration time should be lower than...
With the rapid growth of semantic data, scalable reasoning has attracted more, more attention. However, most existing works about scalable reasoning focus only on RDFS/OWL ter Horst semantics, which are small fragments of OWL 2 RL,, have limitation in expressivity. As OWL 2 RL semantics extended with SWRL rules can be expressed by datalog language, materialization of datalog programs is widely adopted...
In this paper, a hybrid optimization algorithm, consisting of a central force optimization and a gradient-based method, is constructed. The central force optimization is used to locate decent points for previously converged local minima. The combined algorithm balance explores and exploits.
A novel method of locating all local minima of a function is presented here. Among many methods that exist in global optimization literature, Multi-start and Min-finder are effective methods because of their ability to locate not only the global minimum but also all local minima of the objective function. Both of these methods have the disadvantage of high computational cost. To remedy this, we propose...
Anycast is an internet addressing protocol where multiple hosts share the same IP-address. A popular architecture for modern Content Distribution Networks (CDNs) for geo-replicated HTTP-services consists of multiple layers of proxy nodes for service and co-located DNS-servers for load-balancing on different proxies. Both the proxies and the DNS-servers use anycast addressing, which offers simplicity...
Whole genome re-sequencing plays a crucial role in biomedical studies. The emergence of genomic big data calls for an enormous amount of computing power. However, current computational methods are inefficient in utilizing available computational resources. In this paper, we address this challenge by optimizing the utilization of the fastest supercomputer in the world - TH-2 supercomputer. TH-2 is...
Optimal power flow (OPF) is a well known challenging optimization problem for power systems engineering. There have been a myriad of works dedicated to solving OPF problems in a centralized way, i.e. using a centralized solver, which necessitates for a central control center to receive and transmit a large amount of data. Recently, few attempts have been done to solve OPF problems in a distributed...
A Waste Collection Arc Vehicle Routing Problem with turn constraints (WCAVRPTC) model is proposed to minimize the length of municipal solid waste (MSW) collection routes, which presents several characteristics derived from traffic regulations: some streets can be traversed crossed in only one direction, and some turns should be forbidden when the common angle is too narrow. The problem is transformed...
Generally, the goal of reliability allocation is to maximize product reliability under various physical or budgetary constraints, and to minimize cost subject to reliability or physical constraints. For products sold with warranty, the product reliability affects not only the manufacturing cost but also the warranty servicing cost. Thus the reliability allocation decision can be regarded as a multi-objective...
In the process of fast industrialization, wind power generation is restricted by many elements. To better solve the problem of energy storage unit capacity optimization in wind power generating combined with Energy Storage System, and advance the stability of wind generating paralleling operation, a optimization method to calculate the required energy-storage capacity for long-term stable power output...
In this paper, a hybrid descent method, consisting of a genetic algorithm and the filled function method, is proposed. The genetic algorithm is used to locate descent points for previously converged local minima. The combined method has the decent property and the convergence is monotonic. To demonstrate the effectiveness of the proposed hybrid method, several multi-dimensional or non-convex optimization...
The structure of traditional machine tool is designed through experience, analogy, and static traditional design method. The machine structure was heavy and design cycle is long. So the cost is expensive. Therefore, there are a lot of places need improvements. The finite element model of the beam structure was structured by using three-dimensional CAD modeling software-UG NX4.0 and finite element...
In this paper, we describe our experiment developing an implementation of the Linpack benchmark for TianHe-1, a petascale CPU/GPU supercomputer system, the largest GPU-accelerated system ever attempted before. An adaptive optimization framework is presented to balance the workload distribution across the GPUs and CPUs with the negligible runtime overhead, resulting in the better performance than the...
The Embarrassingly Parallel (EP) is one kernel benchmark of NAS Parallel Benchmarks (NPB). EP generates pairs of Gaussian Random Deviates (GRDs) of large random numbers which produced by Linear Congruential Generator (LCG). In this paper, the Hybrid EP is efficient implemented on CPU/GPU heterogeneous platform. Experimental results show that the Hybrid EP is 11.98 times faster than equivalent multicore...
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