An IPPS (inclusion probability proportional to size) sampling scheme

Abstract  In this paper a sampling scheme for selecting a sample of size two is formulated where the inclusion probability of a population unit is proportional to its size.     

CREDIBLY IDENTIFYING SOCIAL EFFECTS: ACCOUNTING FOR NETWORK FORMATION AND MEASUREMENT ERROR

Understanding whether and how connections between agents (networks) such as declared friendships in classrooms, transactions between firms, and extended family connections, influence their socio‐economic outcomes has been a growing area of research within economics. Early methods developed to identify these social effects assumed that networks had formed exogenously, and were perfectly observed, both of which are unlikely to hold in practice. A more recent literature, both within economics and in other disciplines, develops methods that relax these assumptions. This paper reviews that literature. It starts by providing a general econometric framework for linear models of social effects, and illustrates how network endogeneity and missing data on the network complicate identification of social effects. Thereafter, it discusses methods for overcoming the problems caused by endogenous formation of networks. Finally, it outlines the stark consequences of missing data on measures of the network, and regression parameters, before describing potential solutions.     

Choosing a digital content strategy: How much should be free?

Advertising supported content sampling is ubiquitous in online markets for digital information goods. Yet, little is known about the profit impact of sampling when it serves the dual purpose of disclosing content quality and generating advertising revenue. This paper proposes an analytical framework to study the optimal content strategy for online publishers and shows how it is determined by characteristics of both the content market and the advertising market. The strategy choice is among a paid content strategy, a sampling strategy, and a free content strategy, which follow from the publisher's decisions concerning the size of the sample and the price of the paid content. We show that a key driver of the strategy choice is how sampling affects the prior expectations of consumers, who learn about content quality from the inspection of the free samples. Surprisingly, we find that it can be optimal for the publisher to generate advertising revenue by offering free samples even when sampling reduces both prior quality expectations and content demand. In addition, we show that it can be optimal for the publisher to refrain from revealing quality through free samples when advertising effectiveness is low and content quality is high. To illustrate, we relate our framework to the newspaper industry, where the sampling strategy is known as the “metered model.”     

频标计量仪器电路的低噪声设计

本文论述了频标计量仪器中倍频器和分频器两种电路的设计思想。通过对经典电路的分析,简要介绍了降低电路噪声的工艺。实践证明,这些工艺是很有效的。     

样本效应与软件产品定价策略研究

样本试用之所以成为软件产品重要的销售策略,目的在于降低消费者对产品功能水平认知的不确定性,奠定市场基础.基于收益管理理论,结合学习效应和网络外部性,分析消费者行为和市场期望均衡,本文建立了目标最大化的收益模型,探讨了最优的定价策略,通过数值分析相关参数对最优价格、销售量和收益的影响.结论显示:在试用期限的限制下,将最优的定价策略划分为三个区域,包括:(1)无盗版、无威胁;(2)无盗版、有威胁;(3)有盗版;在盗版的风险成本较高情况下,较低的定价和较短的试用期限将发挥优势,并对价格、试用期限、销售量和盗版的风险成本之间地权衡抉择可取得最大收益.     

Existence of balanced sampling plans avoiding cyclic distances

This article considers balanced sampling plans avoiding adjacent units. It is shown, using linear algebraic and design theoretic tools, that such plans exist for all sufficiently large populations. More generally, if any set of m circular distances is to be avoided in balanced sampling with subsets of size k, then such a plan exists, provided the population size N is at least mk ³. Research of the Peter J. Dukes is supported by NSERC.     

A multistage stochastic programming model for the New Zealand dairy industry

This paper presents an application of multistage stochastic programming to a production planning problem for Fonterra, a leading company in the New Zealand dairy industry, taking into account uncertain milk supply, price–demand curves and contracting. We describe a model for Fonterra's supply chain, and a model for uncertain milk supply. We then present a multistage stochastic quadratic programming model and a decomposition algorithm to compute an optimal sales policy, which is tested in simulation against a deterministic policy.     

α-optimal sampling plans for lot-by-lot defects inspection

Investigations on acceptance sampling have attached rather few importance to defects inspection. For modern quality control, both the steadily increasing complexity of products and the need for differentiated cost calculation involve a clear demand for economic defects sampling in its practically most relevant form: lot-by-lot single sampling plans, where the OC (lot OC) is considered as a function of lot sizeN, sample sizen, acceptance numberc, number of defects in the lotK. Starting from an appropriate lot OC function, the present paper develops an economic cost and control model and an economic objective function for single defects sampling plans by adapting theα-optimal sampling scheme, introduced by E. von Collani for defectives inspection, to the purposes of defects inspection. A simple and accurate approximation ofα-optimal defects plans is derived by means of a Poisson approximation of the lot OC function.     

食品抽样检测的方法及技巧研究

三聚氰胺,苏丹红以及地沟油等事件,给人们带来了极大的食品安全隐患,影响了人们身体健康,严重的甚至导致死亡,因此人们对于食品安全越来越重视,对食品安全检测的信任度越来越低。     

The use of sampling methods in advertising research: a gap between theory and practice

In this research note, we reflect critically on the use of sampling techniques in advertising research. Our review of 1028 studies published between 2008 and 2016 in the four leading advertising journals shows that while current academic literature advocates probability sampling procedures, their actual usage is quite scarce. Most studies either lack information on the sampling method used, or engage in non-probability sampling without making adjustments to compensate for unequal selection probabilities, non-coverage, and sampling fluctuations. Based on our results, we call on researchers to revisit the fundamental aspects of sampling to increase their research results’ rigour and relevance.