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101.
Global Optimization in Any Minkowski Metric: A Permutation-Translation Simulated Annealing Algorithm for Multidimensional Scaling 总被引:3,自引:1,他引:2
It is well known that considering a non-Euclidean Minkowski metric in Multidimensional Scaling, either for the distance model
or for the loss function, increases the computational problem of local minima considerably. In this paper, we propose an algorithm
in which both the loss function and the composition rule can be considered in any Minkowski metric, using a multivariate randomly
alternating Simulated Annealing procedure with permutation and translation phases. The algorithm has been implemented in Fortran
and tested over classical and simulated data matrices with sizes up to 200 objects. A study has been carried out with some
of the common loss functions to determine the most suitable values for the main parameters. The experimental results confirm
the theoretical expectation that Simulated Annealing is a suitable strategy to deal by itself with the optimization problems
in Multidimensional Scaling, in particular for City-Block, Euclidean and Infinity metrics. 相似文献
102.
LIU JianCai XU JiaKai NING XinBao TIAN Run 《科学通报(英文版)》2007,52(17):2438-2442
The characterization of non-stationary signal requires joint time and frequency information. However, time and frequency are a pair of non-commuting variables that cannot constitute a joint probability density in the time-frequency plane. The time-frequency distributions have difficult interpretation problems arising from negative and complex values or spurious components. In this paper, we get time-frequency information from the marginal distributions in rotated directions in the time-frequency plane. The rigorous probability interpretation of the marginal distributions is without any ambiguities. This time-frequency transformation is similar to the computerized axial tomography (CT or CAT) and is applied to signal analysis and signal detection and reveals a lot of advantages especially in the signal detection of the low signal/noise (S/N). 相似文献
103.
Alexandra Sauer 《Systemic Practice and Action Research》2008,21(6):497-515
The participation of non-state actors in implementation processes is often understood as a means to increase compliance efficiency.
But the implementation of spatial policies frequently focuses on pre-established goals, processes and instruments and thus
renders difficult open discourse and shared decision-making. This paper introduces conflict pattern analysis (CPA) as a tool
that supports the analysis of the actual actor constellation in order to define efficient approaches that avoid common problems
of participatory processes. CPA is a semi-formalised method that helps to identify key-actors, their relations and interaction
amongst each other as well as their core beliefs, interests and resources. It aggregates this information to interaction patterns
that can be compared, classified and linked to different participatory methods on a theoretically informed basis. Particularly
on the local and regional level, this could be the first step for successful (participatory) implementation strategies. 相似文献
104.
S. K. MISHRA Shouyang WANG K. K. LAI 《系统科学与复杂性》2007,20(3):344-349
In this paper, we introduce a new class of generalized convex function, namely, a-pseudounivex function, by combining the concepts of pseudo-univex and α-invex functions. Further, we establish some relationships between vector variational-like inequality problems and vector optimization problems under the assumptions of α-pseudo-univex functions. Results obtained in this paper present a refinement and improvement of previously known results. 相似文献
105.
A theoretical model for mid-and low-latitude ionospheric electric fields in realistic geomagnetic fields 总被引:1,自引:1,他引:0
The geomagnetic fields, which play important roles in the ionospheric dynamo, can greatly affect the global distribution of ionospheric electric fields, currents and other ionospheric electrodynamics phenomena. In the study of ionospheric electrodynamics phenomena, such as the longitudinal variations of ionospheric electric fields, the non-dipolar component of the geomagnetic fields must be taken into account. In this paper, we deduce a theoretical electric field model for ionospheric dynamo at mid- and low-latitude which adopt a modified magnetic apex coordinates system. In the new electric field model, the geomagnetic fields can be calculated from either the IGRF model or the dipole field model, and the neutral winds and conductivities are calculated based on empirical models. Then the dynamo equation for the electric potential is finally solved in terms of the line-by-line iteration method, and the ionospheric electric fields and currents are derived from the calculated potential. Our model can reproduce the main features of the ionospheric electrodynamics processes, so it will be a useful tool for the investigation of the upper atmosphere and ionosphere. 相似文献
106.
幼儿基本体操是以幼儿为对象,以增强体质为目的的大众健身体操。从幼儿基本体操的概念上、幼儿生理上、心理上、智力发展方面介绍和论述幼儿基本体操对幼儿发育的促进作用。 相似文献
107.
学年学分制模式下的高校学生工作探索 总被引:1,自引:0,他引:1
彭辉 《无锡职业技术学院学报》2008,7(2)
我国目前大多数高校采用学年学分制,与学年制和完全学分制不同,它以学分为计量单位,按学年或学期作为结算时段确定学生的降级和退学标准,有相对固定的修业年限。文章对该模式下的学生工作进行初步探讨,提出了进一步完善辅导员制度、加强班集体建设等系列措施。 相似文献
108.
等截面垂直管道中气粉流的临界管长 总被引:2,自引:1,他引:1
彭一川 《东北大学学报(自然科学版)》1995,16(6):573-578
考虑重力和摩擦力的影响,建立了描述垂直管道中气粉流行为的数学模型,采用马赫数检验法,确定了产生摩擦壅塞时的临界管长,计算表明,当气粉流以不同方式喷入相同的冶金熔池时,底吹垂直管道比顶吹垂直管道需要更大的临界管长。 相似文献
109.
用钾离子选择性电极测定硫酸钾水溶液中缔合反应在不同温度、不同离子强度时△H°、△G°、△S°. 相似文献
110.
双核铕-邻甲基苯甲酸-邻菲罗啉三元配合物的晶体结构王瑞芬,王明昭,金林培,蔡冠梁(北京师范大学化学系,100875,北京;解放军防化指挥工程学院,102205,北京;第一作者,44岁,女,副教授)关键词铕;三元配合物;晶体结构分类号O741.6;O6... 相似文献