The effects of age,viewing distance,display type,font type,colour contrast and number of syllables on the legibility of Korean characters

This study evaluated the effects of age (20s and 60s), viewing distance (50 cm, 200 cm), display type (paper, monitor), font type (Gothic, Ming), colour contrast (black letters on white background, white letters on black background) and number of syllables (one, two) on the legibility of Korean characters by using the four legibility measures (minimum letter size for 100% correctness, maximum letter size for 0% correctness, minimum letter size for the least discomfort and maximum letter size for the most discomfort). Ten subjects in each age group read the four letters presented on a slide (letter size varied from 80 pt to 2 pt). Subjects also subjectively rated the reading discomfort of the letters on a 4-point scale (1 = no discomfort, 4 = most discomfort). According to the ANOVA procedure, age, viewing distance and font type significantly affected the four dependent variables (p < 0.05), while the main effect of colour contrast was not statistically significant for any measures. Two-syllable letters had smaller letters than one-syllable letters in the two correctness measures. The younger group could see letter sizes two times smaller than the old group could and the viewing distance of 50 cm showed letters about three times smaller than those at a 200 cm viewing distance. The Gothic fonts were smaller than the Ming fonts. Monitors were smaller than paper for correctness and maximum letter size for the most discomfort. From a comparison of the results for correctness and discomfort, people generally preferred larger letter sizes to those that they could read. The findings of this study may provide basic information for setting a global standard of letter size or font type to improve the legibility of characters written in Korean.

Statement of Relevance: Results obtained in this study will provide basic information and guidelines for setting standards of letter size and font type to improve the legibility of characters written in Korean. Also, the results might offer useful information for people who are working on design of visual displays.     

Identification of piecewise affine systems based on statistical clustering technique

This paper is concerned with the identification of a class of piecewise affine systems called a piecewise affine autoregressive exogenous (PWARX) model. The PWARX model is composed of ARX sub-models each of which corresponds to a polyhedral region of the regression space. Under the temporary assumption that the number of sub-models is known a priori, the input-output data are collected into several clusters by using a statistical clustering algorithm. We utilize support vector classifiers to estimate the boundary hyperplane between two adjacent regions in the regression space. In each cluster, the parameter vector of the sub-model is obtained by the least squares method. It turns out that the present statistical clustering approach enables us to estimate the number of sub-models based on the information criteria such as CAIC and MDL. The estimate of the number of sub-models is performed by applying the identification procedure several times to the same data set, after having fixed the number of sub-models to different values. Finally, we verify the applicability of the present identification method through a numerical example of a Hammerstein model.     

Discrete logarithms inGF(p)

Several related algorithms are presented for computing logarithms in fieldsGF(p),p a prime. Heuristic arguments predict a running time of exp((1+o(1)) ) for the initial precomputation phase that is needed for eachp, and much shorter running times for computing individual logarithms once the precomputation is done. The running time of the precomputation is roughly the same as that of the fastest known algorithms for factoring integers of size aboutp. The algorithms use the well known basic scheme of obtaining linear equations for logarithms of small primes and then solving them to obtain a database to be used for the computation of individual logarithms. The novel ingredients are new ways of obtaining linear equations and new methods of solving these linear equations by adaptations of sparse matrix methods from numerical analysis to the case of finite rings. While some of the new logarithm algorithms are adaptations of known integer factorization algorithms, others are new and can be adapted to yield integer factorization algorithms.     

改进的基因拷贝数变异检测算法

cnvPartition算法在单核苷酸多态性数据上运算时间复杂度较高。为此,提出一种改进的基因拷贝数变异(CNV)检测算法。将二元分割与cnvPartition算法相结合,优先查找显著变异断点,再检测出隐藏性变异断点。实验结果表明,该算法在位点数增加时,最高可提高50%的检测速度,利于检测出小片段的CNV变异。     

RFID系统中基于公钥加密的相互认证协议

随着RFID系统能力的提高和标签应用的日益普及,安全问题,特别是用户隐私问题变得日益严重。提出了一种新的RFID认证协议。认为基于公钥加密的RFID认证协议相对基于哈希函数和基于对称密钥加密的RFID认证协议,有较好的安全性。公钥加密算法NTRU被认为是一种效率较高的加密算法,且更适合于RFID系统,因此提出的协议采用了NTRU公钥加密算法。对该协议的安全性和性能进行了比较分析,结果表明该协议可以为RFID系统提供更好的安全性,能为用户提供更好的隐私保护,且性能较佳。     

移动网络YouTube视频码率及分辨率识别方法

YouTube作为世界最大的视频网站,在网络流量中的占比日益增加。大量的视频流量给互联网服务提供商带来了巨大的挑战。随着YouTube全站采用HTTPS加密,如何从HTTPS加密流量中获取视频QoE评估信息至关重要。在分析了YouTube App在Android和IOS平台上所采用的流媒体传输模式的基础上,提出了C4.5决策树与[K]-means聚类相结合的方法对视频片段进行分辨率识别。实验结果证明该方法能够准确地识别视频播放过程中每个视频片段的播放码率及分辨率。     

VB实现数字小写转大写算法

在开发一些财经类管理信息系统时,常常遇到人民币阿拉伯数字按照汉语习惯和规定自动转换成大写格式的问题。本文提供了一种简洁明了的算法,并在VB环境下完整实现。     

Minimizing the number of late jobs for the permutation flowshop problem with secondary resources

This paper considers a permutation flowshop problem with secondary resources with the objective of minimizing the number of tardy jobs. The number of secondary resources assigned to the machines (workcenters), as well as the allocation of resources among the various machines, will play a significant role in the time required to process each job by its specified due date. This problem finds application in a large number of environments including manufacturing, maintenance, warehousing operations, as well as in healthcare. The research presents a lower bound for the permutation flowshop problem and evaluates its performance against the optimal solution for small, medium, and large instances. Several heuristics, including neighborhood search and simulated annealing, are presented to generate the secondary resource assignment and the allocation of jobs to the schedule. The computational complexity of the lower bound and computational examples for the heuristics are discussed.     

Experimental study of the flow in helical circular pipes: Torsion effect on the flow velocity and turbulence

An objective of the present paper is to experimentally clarify the torsion effect on the flow in helical circular pipes. We have made six helical circular pipes having different pitches and common non-dimensional curvature δ of about 0.1. The torsion parameter β0, which is defined by β0 = τ/（2δ）1/2 with non-dimensional torsion r, are taken to be 0.02, 0.45, 0.69, 1.01, 1.38 and 1.89 covering from small to very large pitch. The velocity distributions and the turbulence of the flow are measured using an X-type hot-wire anemometer in the range of the Reynolds number from 200 to 20000. The results obtained are summarized as follows： The mean secondary flow pattern in a cross section of the pipe changes from an ordinary twin-vortex type as is seen in a curved pipe without torsion （toroidal pipe） to a single vortex type after one of the twin-vortex gradually disappears as β0 increases. The circulation direction of the single vortex is the same as the direction of torsion of the pipe. The mean velocity distribution of the axial flow is similar to that of the toroidal pipe at small β0, but changes its shape as β0 increases, and attains the shape similar to that in a straight circular pipe when ,β0 = 1.89. It is also found that the critical Reynolds number, at which the flow shows a marginal behavior to turbulence, decreases as ,β0 increases for small ,β0, and then increases after taking a minimum at ,β0 ≈ 1.4 as ,β0 increases. The minimum of the critical Reynolds number experimentally obtained is about 400 at ,β0 ≈ 1.4.     

喷气纺纱喷嘴安装位置对成纱强力的影响

研究了喷气纺纱喷嘴安装位置有关参数及解捻管槽数对成纱强力的影响规律。试验结果表明：一级喷嘴与前钳口间距存在临界值，当间距为11mm时成纱强力最高；当两级喷嘴间距为4mm时，成纱强力较高且波最小；异纱钩与二级喷嘴的最佳 间距为88mm，该距离过大过小成纱强力均有降低；随着解捻管槽数的增加，成纱强力提高，实际生是中可选 用四槽。