景观设计思维的培养途径与教学探讨——从设计思维的特性谈起

作为一门以落地性为特征的应用型学科,对学生规划设计思维与能力的培养一直是风景园林专业教学的重要目标,如何通过教学有效地培养学生规划设计思维与能力也成为了风景园林专业教育关注的重要议题。本文从设计思维的特性出发,针对设计教学课程提出了一套控制方式和流程,并以同济大学本科三年级上学期的公园设计课程为例,对景观设计思维的培养途径和方法展开了教学尝试。     

Sample Size Requirements in Studies of the Etiologic Fraction

This paper outlines methods of determining sample size for epidemiologic research in studies of the etiologic fraction. The basic model with a dichotomous disease and a single dichotomous exposure factor is considered. To determine sample size, the researcher must specify: the magnitude of the etiologic fraction ε to be detected as statistically significant, the level of significance α, the power 1 - β of the test, p the proportion of the population exposed to the risk factor and R the proportion of the population with the disease. Sample size formulas and tables are presented for the case-control, cohort and cross-sectional designs. Optimal allocation considerations are examined to minimize cost for a specified power. Extensive use is made of Walter's results concerning the asymptotic variance of the maximum likelihood estimator of the etiologic fraction for the three epidemiologic study designs.     

Construction of Equi-replicated Balanced Block Designs with Block Sizes Exceeding the Number of Treatments

In this note it is shown that the block design with incidence matrix Ñ = [NN… N], where N = c_1hN_h + c_oh (11′–N_h). c_oh and c_1h are any non-negative integers and N_h,h = 1, 2,…,p, are incidence matrices of balanced incomplete block designs with the same number of treatments t, is a balanced block design with the block sizes exceeding the number of treatments. In derivation the matrix M₀, introduced by CALIński (1971) is utilized.     

On the PBB Designs for Multiresponse Experiments

We present the idea of using multiresponse incomplete block designs when not all responses can be observed in all experimental units. For a special class of such designs, in which partial designs are PBB designs, a method for estimating natural treatment contrast is given. We also consider the problem of testing the hypotheses concerning the natural and any estimable treatment contrasts. For testing this hypothesis the Wald statistics, being asymptotically chi-square distributed, is proposed.     

Application of the Biased Spring Balance Weighing Design Theory to Estimation of Differences of Line Effects for Legume Content

The incidence matrix of a BIB design for v treatments has been used to construct a biased spring balance weighing design. Conditions under which an optimum biased spring balance weighing design exists are given. It is also shown how this theory may be utilized to obtain treatment and experiment designs to estimate differences in legume content between pair of lines in an experiment overseeded with grass species.     

生物工程专业“试验设计与数据处理”教学中常用软件的探讨

试验设计与数据处理在生物工程专业方向有着重要的应用,但是在本科教学中开设该课程的高校较少。本文结合生物工程中的常见案例,对该课程教学过程中常用的软件包括Excel、正交试验设计助手、Data processing system(DPS)和Design expert在单因素、多因素、正交、均匀、P-B(Plackett-Burman)和响应面等数据处理方法进行了探讨。通过比较分析各种软件和数据处理方法之间特点,增加该课程教学的实践性和应用性,从而提高教学质量。     

Relative Efficiency of the Case-Control to the Cohort Design in Epidemiology

In deriving the efficiency of the stratified to the simple random sample design in survey research, the critical link between the designs is the population analysis of variance. Analogously, the efficiency of the case-control to the cohort design in epidemiologic research can be derived using Bayes' theorem as the essential connection between the designs. Prior information on the odds of the disease is also required. A numerical example using data from Fleiss' text is used to illustrate the result.     

应用试验设计提高蝮蛇抗栓酶产量的研究

试验设计是研究使试验过程科学化、合理化的一门学科。本文介绍了应用试验设计方法寻找生产蝮蛇抗栓酶的最佳工艺,从而有效地提高了产品产量,并取得明显经济效益     

Precision of Estimation of the Treatment Contrasts and the Intra-block Matrix of Block Designs

In many practical situations the experiment is conducted using a block design, and it is desired to estimate a given set of contrasts with variances none of which is greater than a corresponding set of specified variances: In the present paper the form of the intra-block matrix of a design is, therefore, derived for such situations. Usefulness of the results given is illustrated with the help of examples. The construction of two-plot block designs is shown to be particularly straightforward.     

Extension of the rank sum test for clustered data: two-group comparisons with group membership defined at the subunit level

The Wilcoxon rank sum test is widely used for two-group comparisons for nonnormal data. An assumption of this test is independence of sampling units both between and within groups. In ophthalmology, data are often collected on two eyes of an individual, which are highly correlated. In ophthalmological clinical trials, randomization is usually performed at the subject level, but the unit of analysis is the eye. If the eye is used as the unit of analysis, then a modification to the usual Wilcoxon rank sum variance formula must be made to account for the within-cluster dependence. For some clustered data designs, where the unit of analysis is the subunit, group membership may be defined at the subunit level. For example, in some randomized ophthalmologic clinical trials, different treatments may be applied to fellow eyes of some patients, while the same treatment may be applied to fellow eyes of other patients. In general, binary eye-specific covariates may be present (scored as exposed or unexposed) and one wishes to compare nonnormally distributed outcomes between exposed and unexposed eyes using the Wilcoxon rank sum test while accounting for the clustering. In this article, we present a corrected variance formula for the Wilcoxon rank sum statistic in the setting of eye (subunit)-specific covariates. We apply it to compare ocular itching scores in ocular allergy patients between eyes treated with active versus placebo eye drops, where some patients receive the same eye drop in both eyes, while other patients receive different eye drops in fellow eyes. We also present comparisons between the clustered Wilcoxon test and each of the signed rank tests and mixed model approaches and show dramatic differences in power in favor of the clustered Wilcoxon test for some designs.     

Restricted sidechain plasticity in the structures of native proteins and complexes

Protein-design methodology can now generate models of protein structures and interfaces with computed energies in the range of those of naturally occurring structures. Comparison of the properties of native structures and complexes to isoenergetic design models can provide insight into the properties of the former that reflect selection pressure for factors beyond the energy of the native state. We report here that sidechains in native structures and interfaces are significantly more constrained than designed interfaces and structures with equal computed binding energy or stability, which may reflect selection against potentially deleterious non-native interactions.     

Model building and testing for the change-over design

The two-period cross-over design is discussed within the framework of univariate and multivariate analysis of variance technique; the relations between both procedures are explained. It is shown that all hypotheses of interest can be tested if the design is regarded as a special case of a repeated measurement design. Some features of the n-period change-over design are explained by discussing the model and hypotheses of a three-period design.