A survey on nonadaptive group testing algorithms through the angle of decoding

Group testing, sometimes called pooling design, has been applied to a variety of problems such as blood testing, multiple access communication, coding theory, among others. Recently, screening experiments in molecular biology has become the most important application. In this paper, we review several models in this application by focusing on decoding, namely, giving a comparative study of how the problem is solved in each of these models.     

Hypothesis group testing for disjoint pairs

Classical group testing (CGT) is a widely applicable biotechnical technique used to identify a small number of distinguished objects from a population when the presence of any one of these distinguished objects among a group of others produces an observable result. This paper discusses a variant of CGT called group testing for disjoint pairs (GTAP). The difference between the two is that in GTDP, the distinguished items are pairs from, not individual objects in, the population. There are several biological examples of when this abstract model applies. One biological example is DNA hybridization. The presence of pairs of hybridized DNA strands can be detected in a pool of DNA strands. Another situation is the detection of binding interactions between prey and bait proteins. This paper gives a random pooling method, similar in spirit to hypothesis testing, which identifies pairs of objects from a population that collectively have an observable function. This method is simply to apply, achieves good results, is amenable to automation and can be easily modified to compensate for testing errors. M.A. Bishop is supported by AFOSR FA8750-06-C-0007. A.J. Macula is supported by NSF-0436298, AFOSR FA8750-06-C-0007.     

Probabilistic Nonadaptive and Two-Stage Group Testing with Relatively Small Pools and DNA Library Screening

We use a simple, but nonstandard, incidence relation to construct probabilistic nonadaptive group testing algorithms that identify many positives in a population with a zero probability of yielding a false positive. More importantly, we give two-stage modifications of our nonadaptive algorithms that dramatically reduce the expected number of sufficient pools. For our algorithms, we give a lower bound on the probability of identifying all the positives and we compute the expected number of positives identified. Our method gives control over the pool sizes. In DNA library screening algorithms, where relatively small pools are generally preferred, having control over the pool sizes is an important practical consideration.     

DNA Screening, Pooling Design and Simplicial Complex

Pooling designs are used for DNA library screening. In this paper, we present a construction of pooling design with simplicial complex and establish some general results on the construction.     

Quantitative Theory,Methodology and Technique

In hypothesis testing, the level of significance, α, often performs a screening as well as an evaluating function. Results which are not “significant” at some preset value of α are simply not reported. Unfortunately, this value of α is usually arbitrarily set at .05 or .01 and bears no relation to the needs of potential users of the study. This paper suggests an approach to making the selection of α more responsive to these potential applications.     

Online graph exploration algorithms for cycles and trees by multiple searchers

This paper deals with online graph exploration problems by multiple searchers. The information on the graph is given online. As the exploration proceeds, searchers gain more information on the graph. Assuming an appropriate communication model among searchers, searchers can share the information about the environment. Thus, a searcher must decide which vertex to visit next based on the partial information on the graph gained so far by searchers. We assume that all searchers initially start the exploration at the origin vertex, and the goal is that each vertex is visited by at least one searcher and all searchers finally return to the origin vertex. The objective is to minimize the time when the goal is achieved. We study the case of cycles and trees. For the former, we give an optimal online exploration algorithm in terms of competitive ratio, and for the latter, we also give an online exploration algorithm which is optimal among greedy algorithms.     

基于Copula变点检测的美国次级债金融危机传染分析

金融危机传染的分析是国际金融研究中的重要问题,大多数传染效应存在性的检验采用相关性方法,本文通过阿基米德Copula的变点检测方法来检验传染效应的存在性,更加全面地分析了国家收益率之间的相依结构,并以两个国家收益率的尾部相依指数作为传染程度大小的一种度量。最后对亚洲几个主要市场的指数和S&P500指数数据进行了实证分析,研究美国次级债金融危机对亚洲市场的传染效应。     

基于ECA规则的工作流时间约束分析

本文着重研究了工作流中各活动间的定量时序关系,提出了一种分析工作流中时间约束的方法。该方法针对基于ECA规则的工作流,通过建立及分析工作流的约束图,对工作流中活动间定量时序约束的一致性进行了分析,从而保证了工作流的正常运行。     

复杂技术系统背景下技术体制新解

在解释技术体制、技术范式和技术轨迹间的关系,并指出原有技术体制在复杂技术系统下存在的缺陷的基础上,引入技术场网络作为技术体制的新维度,解释复杂技术系统中技术场网络主体间的技术联系,并区分了这种技术联系的强弱,讨论了技术体制的新维度与原有维度间的关系,提出了相应的假设。     

Radon Testing Behavior in a Sample of Individuals with High Home Radon Screening Measurements

Although radon exposure has been identified as the second leading cause of lung cancer, fewer than 6% of U.S. homeowners test their homes for radon. This report examines participants'follow-up radon testing behavior subsequent to receiving an initial screening radon level greater than 20 pCi/L. Sixty-two participants in the Iowa State-Wide Rural Radon Screening Survey who had radon screening measurements over 20 pCi/L were questioned by phone survey 3 months after receipt of their radon screening result to assess: whether participants were aware of radon's health risk; if participants recalled the radon screening results; how participants perceived the relative health risk of radon and whether participants planned follow-up radon testing. Only 19% of the respondents specifically identified lung cancer as the possible adverse health outcome of high radon exposure, and the majority of participants underestimated the health risks high radon levels pose when compared to cigarettes and x-rays. In addition, less than one third (29%)of the participants actually remembered their radon screening level within 10 pCi/L 3 months after receiving their screening results. Only 53% of the individuals correctly interpreted their screening radon level as being in the high range, and only 39% of the participants planned follow-up radon measurements. Receipt of radon screening test results indicating high radon levels was not an adequate motivational factor in itself to stimulate further radon assessment or mitigation. Our findings suggest that free radon screening will not result in a dramatic increase in subsequent homeowner initiated remediation or further recommended radon testing.     

属性值为区间数的多属性决策对象排序研究

多属性决策问题的实质利用已有决策信息,通过一定方式对备选方案进行排序和择优。针对属性值为区间数的多属性决策对象排序问题,首先,提出决策对象优势关系这一概念,再次,得出决策对象的优势关系与其属性值两端点的实数值之和存在等价关系;最后,利用属性值为区间数的多属性决策实例对该算法进行了实例分析,并利用优势关系对决策对象进行排序并择优。     

证券组合有效子集的统计检验及实证研究

本文研究了投资组合管理中的证券子集选择问题,通过分析证券组合有效子集与均值-方差张成的关系,给出了一种新的基于统计推断的证券子集有效性检验方法,同时也拓展了Huberman和Kandel的均值-方差张成条件。实证结果表明,本文的方法相对于现有的基于矩阵秩的判别方法更稳健。     

Finding a minimal spanning hypertree of a weighted hypergraph

Journal of Combinatorial Optimization - A hypergraph has a complex structure, which is why some re- searchers seek to transform the hypergraph into a graph. In this paper, we present two...     

Locating independent facilities with maximum weight: Greedy heuristics

The problem is to locate a maximum-weight set of facilities such that no two are closer than a given distance from each other. The unweighted version is equivalent to the maximum independent set problem in graph theory. This paper presents four greedy heuristics and shows that they all have bad worst-case behavior. Empirically, however, these heuristics perform quite well in the relatively large test problems generated randomly.     

Consistent Moment Selection Procedures for Generalized Method of Moments Estimation

This paper considers a generalized method of moments (GMM) estimation problem in which one has a vector of moment conditions, some of which are correct and some incorrect. The paper introduces several procedures for consistently selecting the correct moment conditions. The procedures also can consistently determine whether there is a sufficient number of correct moment conditions to identify the unknown parameters of interest. The paper specifies moment selection criteria that are GMM analogues of the widely used BIC and AIC model selection criteria. (The latter is not consistent.) The paper also considers downward and upward testing procedures. All of the moment selection procedures discussed in this paper are based on the minimized values of the GMM criterion function for different vectors of moment conditions. The procedures are applicable in time-series and cross-sectional contexts. Application of the results of the paper to instrumental variables estimation problems yields consistent procedures for selecting instrumental variables.     

资本结构、股权结构、成长机会与公司绩效

本文在代理成本理论的架构下,以公司成长机会为背景,分析了资本结构和股权结构对公司绩效的影响,并利用 1998 年年底之前在上海和深圳两个交易所上市的 498 家上市公司 1999 至 2001 年三年间1494 个观察值为样本进行了实证分析。结果表明,对于不同成长性的公司而言, 资本结构和股权结构对公司绩效的影响存在较大差异,从而为我们选择理想的资本结构和股权结构提供了有益的启示。     

Organizational Learning,knowledge creation,problem formulation and innovation in messy problems

This paper attempts to bring the discussion about knowledge creation, innovation and organizational learning to a level that addresses how messy problems are addressed and how the organizations must integrate the viewpoints of the key decision-makers, establish a process for testing their assumptions, include the context including the environment design, and to allow innovation and creativity to enter the choice of actions. It builds on the literature of problem formulation, innovation, and experimentation and on the articles in this special issue.     

The optimum traversal of a graph

For a given graph (network) having costs [c_ij] associated with its links, the present paper examines the problem of finding a cycle which traverses every link of the graph at least once, and which incurs the minimum cost of traversal. This problem (called thegraph traversal problem, or theChinese postman problem [9]) can be formulated in ways analogous to those used for the well-known travelling salesman problem, and using this apparent similarity, Bellman and Cooke [1] have produced a dynamic programming formulation. This method of solution of the graph traversal problem requires computational times which increase exponentially with the number of links in the graph. Approximately the same rate of increase of computational effort with problem size would result by any other method adapting a travelling salesman algorithm to the present problem.This paper describes an efficient algorithm for the optimal solution of the graph traversal problem based on the matching method of Edmonds [5, 6]. The computational time requirements of this algorithm increase as a low order (2 or 3) power of the number of links in the graph. Computational results are given for graphs of up to 50 vertices and 125 links.The paper then discusses a generalised version of the graph traversal problem, where not one but a number of cycles are required to traverse the graph. In this case each link has (in addition to its cost) a quantity q_ij associated with it, and the sum of the quantities of the links in any one cycle must be less than a given amount representing the cycle capacity. A heuristic algorithm for the solution of this problem is given. The algorithm is based on the optimal algorithm for the single-cycle graph traversal problem and is shown to produce near-optimal results.There is a large number of possible applications where graph traversal problems arise. These applications include: the spraying of roads with salt-grit to prevent ice formation, the inspection of electric power lines, gas, or oil pipelines for faults, the delivery of letter post, etc.