Japan is facing a demographic challenge of a falling birthrate coupled with an aging society that is already adversely affecting the economy. The situation is only expected to worsen as the working-age population cont...Japan is facing a demographic challenge of a falling birthrate coupled with an aging society that is already adversely affecting the economy. The situation is only expected to worsen as the working-age population continues to decrease. Well aware of this situation, businesses and offices are seeking ways to enhance the intellectual productivity of their workers. This paper explores environmental elements of work spaces that might stimulate intellectual activity. Using a CAD （AutoCAD） miniature garden program, subjects were asked to design a project room that is optimized for creative work using a certain number of elements--11 types of walls, 14 types of floors, 4 types of scenery, 3 types of furniture and 3 types of plantings--but the subjects were free to position and arrange these elements any way they want. The subjects were then interviewed using the evaluation grid method. Based on the results, we created an evaluation structure diagram by analyzing key words and phrases emphasized by subjects in the interviews. The overall evaluation structure represents a summary overview of all 30 subjects who participated in the experiment. This approach captures all the key elements of the office environment that might be used to stimulate intellectual activity of employees.展开更多
Electrical capacitance tomography （ECT） is a promising technique for multi-phase flow measurement due to its high speed, low cost and non-intrusive sensing. Image reconstruction for ECT is an inverse problem of find...Electrical capacitance tomography （ECT） is a promising technique for multi-phase flow measurement due to its high speed, low cost and non-intrusive sensing. Image reconstruction for ECT is an inverse problem of finding the permittivity distribution of an object by measuring the electrical capacitances between sets of electrodes placed around its periphery. The conjugate gradient （CG） method is a popular image reconstruction method for ECT, in spite of its low convergence rate. In this paper, an advanced version of the CG method, the projected CG method, is used for image reconstruction of an ECT system. The solution space is projected into the Kryiov subspace and the inverse problem is solved by the CG method in a low-dimensional specific subspace. Both static and dynamic experiments were carried out for gas-solid two-phase flows. The flow regimes are identified using the reconstructed images obtained with the projected CG method. The results obtained indicate that the projected CG method improves the quality of reconstructed images and dramatically reduces computation time, as compared to the traditional sensitivity, Landweber, and CG methods. Furthermore, the projected CG method was also used to estimate the important parameters of the pneumatic conveying process, such as the volume concentration, flow velocity and mass flow rate of the solid phase. Therefore, the projected CG method is considered suitable for online gas-solid two-phase flow measurement,展开更多
In a computing platform composed of several homogeneous processors,any parallel schedule of an algorithm usually involves three basic costs:arithmetic throughput on each processor,data movement between processors,and ...In a computing platform composed of several homogeneous processors,any parallel schedule of an algorithm usually involves three basic costs:arithmetic throughput on each processor,data movement between processors,and synchronization latency for several processors.The trade-offs between these three costs could realistically reflect lower bounds on the execution time for an algorithm.Therefore,the trade-off analysis is important for evaluating the optimality of a proposed schedule,and often yields new insights in parallel optimization.In this paper,we focus on the trade-offs between computation,communication,and synchronization in the stencil-collective alternate update,which is often executed repeatedly by the complex workflow with multiple stages in most numerical methods,such as the conjugate gradient(CG)method,the nonlinear time integration method in the dynamical core of a global atmospheric general circulation model(AGCM),and so on.Firstly,in order to formalize a workflow with multiple different stages,a novel operator representation of parallel algorithms is proposed.Based on the operator representation,we find the minimum vertex separator of the dependency graph for a stencil-collective alternate update.This breakthrough brings us the opportunity to obtain the cost lower bounds.Next,the general trade-off theory of the stencil-collective alternate update is founded successfully,which extends the recent trade-off theory to a more general theoretical context.Finally,by applying the general theoretical result to several algorithms,namely CG method and the nonlinear time integration method in AGCM,we obtain the corresponding lower bounds of computational cost,communication throughput,and synchronization latency.It should be noted that the general theory can also be widely used to analyze other complex numerical methods in real-world applications.展开更多
文摘Japan is facing a demographic challenge of a falling birthrate coupled with an aging society that is already adversely affecting the economy. The situation is only expected to worsen as the working-age population continues to decrease. Well aware of this situation, businesses and offices are seeking ways to enhance the intellectual productivity of their workers. This paper explores environmental elements of work spaces that might stimulate intellectual activity. Using a CAD （AutoCAD） miniature garden program, subjects were asked to design a project room that is optimized for creative work using a certain number of elements--11 types of walls, 14 types of floors, 4 types of scenery, 3 types of furniture and 3 types of plantings--but the subjects were free to position and arrange these elements any way they want. The subjects were then interviewed using the evaluation grid method. Based on the results, we created an evaluation structure diagram by analyzing key words and phrases emphasized by subjects in the interviews. The overall evaluation structure represents a summary overview of all 30 subjects who participated in the experiment. This approach captures all the key elements of the office environment that might be used to stimulate intellectual activity of employees.
基金support from the National Natural Science Foundation of China(50937005,61001135,61201350)the Natural Science Foundation of Tianjin Municipal Science and Technology Commission(11JCYBJC06900)
文摘Electrical capacitance tomography （ECT） is a promising technique for multi-phase flow measurement due to its high speed, low cost and non-intrusive sensing. Image reconstruction for ECT is an inverse problem of finding the permittivity distribution of an object by measuring the electrical capacitances between sets of electrodes placed around its periphery. The conjugate gradient （CG） method is a popular image reconstruction method for ECT, in spite of its low convergence rate. In this paper, an advanced version of the CG method, the projected CG method, is used for image reconstruction of an ECT system. The solution space is projected into the Kryiov subspace and the inverse problem is solved by the CG method in a low-dimensional specific subspace. Both static and dynamic experiments were carried out for gas-solid two-phase flows. The flow regimes are identified using the reconstructed images obtained with the projected CG method. The results obtained indicate that the projected CG method improves the quality of reconstructed images and dramatically reduces computation time, as compared to the traditional sensitivity, Landweber, and CG methods. Furthermore, the projected CG method was also used to estimate the important parameters of the pneumatic conveying process, such as the volume concentration, flow velocity and mass flow rate of the solid phase. Therefore, the projected CG method is considered suitable for online gas-solid two-phase flow measurement,
基金supported by the National Key Research and Development Program of China under Grant No.2016YFB0200800National Natural Science Foundation of China under Grant No.61802369.
文摘In a computing platform composed of several homogeneous processors,any parallel schedule of an algorithm usually involves three basic costs:arithmetic throughput on each processor,data movement between processors,and synchronization latency for several processors.The trade-offs between these three costs could realistically reflect lower bounds on the execution time for an algorithm.Therefore,the trade-off analysis is important for evaluating the optimality of a proposed schedule,and often yields new insights in parallel optimization.In this paper,we focus on the trade-offs between computation,communication,and synchronization in the stencil-collective alternate update,which is often executed repeatedly by the complex workflow with multiple stages in most numerical methods,such as the conjugate gradient(CG)method,the nonlinear time integration method in the dynamical core of a global atmospheric general circulation model(AGCM),and so on.Firstly,in order to formalize a workflow with multiple different stages,a novel operator representation of parallel algorithms is proposed.Based on the operator representation,we find the minimum vertex separator of the dependency graph for a stencil-collective alternate update.This breakthrough brings us the opportunity to obtain the cost lower bounds.Next,the general trade-off theory of the stencil-collective alternate update is founded successfully,which extends the recent trade-off theory to a more general theoretical context.Finally,by applying the general theoretical result to several algorithms,namely CG method and the nonlinear time integration method in AGCM,we obtain the corresponding lower bounds of computational cost,communication throughput,and synchronization latency.It should be noted that the general theory can also be widely used to analyze other complex numerical methods in real-world applications.
