网络型产业的网络效应与一般规模经济效应的特征分析

网络型产业在其增长过程中具有与其它产业不同的经济特征,本文借用系统经济学中的泛权场网模型,将网络效应同一般规模经济效应进行对比分析。解释和描述了网络型效应调整过程中存在的离散性、网络型效应增长的内部协同和溢出贡献问题,并尝试定性地给出网络型产业的边界。本文通过一个新的视角,对以往将网络型产业网络效应简单等同一般规模经济效应的观点给予了修正和解释,并为进一步深入研究网络型产业特征和发展规律提供新的思路。     

ASYMPTOTIC POSTERIOR NORMALITY FOR STOCHASTIC PROCESSES: A NON-ERGODIC EXAMPLE

Sweeting & Adekola (1987) presented a fairly general set of conditions, covering a wide class of problems, that establish asymptotic posterior normality for stochastic processes. In this paper, this theory is illustrated via a non-ergodic example, namely, the class of non-homogeneous birth processes.     

A modified chi-square test of independence against a class of ordered alternatives in an r x c contingency table

A modified chi-square test statistic is constructed for testing the hypothesis of independence in a two-way contingency table against a class of ordered alternatives defined in terms of pooled cross-product ratios. The test procedure can also be used to test for positive quadrant dependence in a two-way contingency table. The asymptotic distribution of the test statistic under the null hypothesis is obtained. Some power comparisons with known test procedures are given. A numerical example is given to illustrate the use of this test.     

Evaluating the relative accuracy and significance of net migration estimates

This paper presents the elements of a theory for evaluating the quality of a set of net migration estimates. The total error in a net migration estimate is decomposed into total bias and total variation. The bias is further decomposed into three bias elements-selection bias, estimator bias, and measurement bias. Tables of bounds for measurement and estimator biases in the vital statistics and the forward survival ratio estimates of net intercensal migration are presented. Both net migration levels and net migration ratios are treated, and provision is made for both life table and census survival ratio estimates. Some of the statistical tables are applied illustratively to net migration data for Canadian counties or census divisions during the 1951-61 decade. Tests of significance and confidence intervals are indicated for net migration estimates, and the basic technical notes are presented in appendices.     

Microstructural analysis in interorganizational systems

This paper argues that network analyses of interorganizational relations should begin by examining the way in which relations are organized at the local level. It posits that systematic departures from random models for dyad and triad censuses should be found before interpreting structural patterns isolated by analytic techniques concerned with overall network structure. Three principles of organizational bonding (resource inequality, reciprocity, and redundancy) are identified, and the implications of these for dyadic and triadic microstructures are detailed. Particular attention is given to differentiating between microstructural patterns to be anticipated when a system consists of autonomous actors approximately equal in power and resources and those expected when a system is highly centralized.     

Teenagers,Contraception, and Pregnancy*

A cooperative program is reported which makes available to the school a series of group discussions on boy-girl relations, sexual physiology, venereal disease, and contraception. Girls attending these sessions, if they so desire, may attend the University Hospital Teen Clinic for physical examination and contraceptive supplies. One hundred and seventy students attended groups, of whom 74 attended teen clinics, and 61 became contraceptors. A second city high school has been added to the program. Staff believes that as young women learn that pregnancy is their choice, they will move into responsible relationships with ability to handle adequately planned motherhood.