A Permutation-Translation Simulated Annealing Algorithm for L1 and L2 Unidimensional Scaling

Given a set of objects and a symmetric matrix of dissimilarities between them, Unidimensional Scaling is the problem of finding a representation by locating points on a continuum. Approximating dissimilarities by the absolute value of the difference between coordinates on a line constitutes a serious computational problem. This paper presents an algorithm that implements Simulated Annealing in a new way, via a strategy based on a weighted alternating process that uses permutations and point-wise translations to locate the optimal configuration. Explicit implementation details are given for least squares loss functions and for least absolute deviations. The weighted, alternating process is shown to outperform earlier implementations of Simulated Annealing and other optimization strategies for Unidimensional Scaling in run time efficiency, in solution quality, or in both.     

On the Performance of Simulated Annealing for Large-Scale L2 Unidimensional Scaling

In this research note, I present a modified version of G. De Soete, L. Hubert, and P. Arabie’s (1988) simulated annealing approach for the problem of L₂ unidimensional scaling via maximization of the Defays criterion. The modifications include efficient storage and computation methods that facilitate rapid evaluation of trial solutions. The results of two experimental studies indicate that the enhanced simulated annealing algorithm is competitive with A. Murillo, J.F. Vera, and W.J. Heiser’s (2005) recently published pertsaus2 procedure in terms of solution quality and computation time. Both Fortran and MatLab versions of this modified simulated annealing implementation are available from the author.     

Global Optimization in Any Minkowski Metric: A Permutation-Translation Simulated Annealing Algorithm for Multidimensional Scaling

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.     

加强高校基础研究 建设世界一流大学——基于清华百年基础研究的思考

清华大学已走过百年历程,基础研究作为学校科研工作重要部分,百年来也取得了丰硕成果.本文通过对比研究清华大学与国家的基础研究发展状况,深入分析清华大学基础研究发展模式,说明在新的百年起点上,基础研究需坚持已有的支持模式,同时继续鼓励创新,实施人才战略,营造宽松环境,以期提升原始创新能力.     

《古生物学名词》(第二版):献给中国古生物学会80华诞的一份厚礼

2009年10月,中国古生物学会第十次全国会员代表大会暨第25届学术年会和纪念中国古生物学会成立80周年大会在南京召开,会议举行了<古生物学名词>(第二版)发布仪式.     

丁韪良早期科学活动及科学辅教观——基于长老会档案的分析

美国北长老会传教士丁韪良是开埠后来华传教士中较早提出传播科学辅助传教,并积极实践这一思想者之一.本文试图通过原始材料,厘清他在宁波、北京两地传教时期(1850-1868)的科学活动,并分析他此段时期的科学辅助传教思想及其对后期活动的影响.     

多模态大数据语境下科技术语翻译标准分析——以新冠肺炎和新冠病毒术语翻译为例

科技术语翻译在全球贸易、科技传播中起着举足轻重的作用,但还存在不准确、不规范和不一致等现象,例如在线词典、机器翻译引擎、在线百科等提供的新冠肺炎和新冠病毒的译法。梳理了科技术语翻译标准和多模态大数据语境理论框架。基于科技术语与翻译方面权威的规范文献的国际国内标准和术语翻译标准的相关研究等可归纳为准确、简明、一致、规范的术语翻译标准;多模态大数据语境则指术语可通过文本、图片、网页等多模态语境传播,整个网络具有多模态语境互文性。文章以新冠肺炎和新冠病毒术语翻译标准化为例,基于网络、数据库检索、图文等互文性语境,以及现有相关研究,分析在科普和学术论文场合的翻译惯例,根据术语翻译标准,更全面归纳了标准化汉英翻译,包括优选术语、全称、曾称和简称等,示范了英语科技论文中全称和简称的写作方式等,可为在线词典、机器翻译中术语优化和科技名词规范等术语翻译标准化相关工作提供参考。     

地理学术语中基元隐喻构词元素的类别特征和构词价值——以《地理学名词》(第2版)为例

文章从术语学角度出发,在分析地理学术语中基元隐喻构词元素的结构形式、基本类型及其特征的基础上,总结基元隐喻构词元素在地理学术语命名中的应用价值及运用策略,并对基元隐喻构词元素的形象性与地理学科术语命名的科学性、准确性之间的关系进行探讨,以期为学科术语命名提供参考。     

我国最早的道教炼丹实物——绵阳双包山汉墓出土金汞合金的初步研究

四川绵阳双包山2号西汉墓出土一块银白色膏状金属,据检测,它主要由液态汞和金汞合金颗粒组成,即所谓的金汞齐;结合文献分析,可知它是我国迄今为止发现的最早的方士的炼丹实物;同墓出土的银缕玉衣、木璧、人体经脉漆雕、陶质丹丸等文物是炼丹实物的旁证。