An efficient FPRAS type group testing procedure to approximate the number of defectives

In many fault detection problems, we want to detect or identify defective items in a sample set by using the minimum number of tests. Group testing is for the scenario where each test is on a subset of items, and tells whether the subset contains at least one defective item or not. Another practically important problem is to estimate the number of defective items in a sample set. In this paper, we present an efficient FPRAS (fully polynomial-time randomized approximation scheme) type group testing procedure to approximate the number of defective items in a sample set.     

Improved adaptive group testing algorithms with applications to multiple access channels and dead sensor diagnosis

We study group-testing algorithms for resolving broadcast conflicts on a multiple access channel (MAC) and for identifying the dead sensors in a mobile ad hoc wireless network. In group-testing algorithms, we are asked to identify all the defective items in a set of items when we can test arbitrary subsets of items. In the standard group-testing problem, the result of a test is binary—the tested subset either contains defective items or not. In the more generalized versions we study in this paper, the result of each test is non-binary. For example, it may indicate whether the number of defective items contained in the tested subset is zero, one, or at least two. We give adaptive algorithms that are provably more efficient than previous group testing algorithms. We also show how our algorithms can be applied to solve conflict resolution on a MAC and dead sensor diagnosis. Dead sensor diagnosis poses an interesting challenge compared to MAC resolution, because dead sensors are not locally detectable, nor are they themselves active participants. A preliminary version of this paper was presented at SPAA 2006.     

Reconstruction of hidden graphs and threshold group testing

Classical group testing is a search paradigm where the goal is the identification of individual positive elements in a large collection of elements by asking queries of the form “Does a set of elements contain a positive one?”. A graph reconstruction problem that generalizes the classical group testing problem is to reconstruct a hidden graph from a given family of graphs by asking queries of the form “Whether a set of vertices induces an edge”. Reconstruction problems on families of Hamiltonian cycles, matchings, stars and cliques on n vertices have been studied where algorithms of using at most 2nlg?n,(1+o(1))(nlg?n),2n and 2n queries were proposed, respectively. In this paper we improve them to \((1+o(1))(n\lg n),(1+o(1))(\frac{n\lg n}{2}),n+2\lg n\) and n+lg?n, respectively. Threshold group testing is another generalization of group testing which is to identify the individual positive elements in a collection of elements under a more general setting, in which there are two fixed thresholds ? and u, with ?<u, and the response to a query is positive if the tested subset of elements contains at least u positive elements, negative if it contains at most ? positive elements, and it is arbitrarily given otherwise. For the threshold group testing problem with ?=u?1, we show that p positive elements among n given elements can be determined by using O(plg?n) queries, with a matching lower bound.     

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.     

Price promotions,operations cost,and profit in a two-stage supply chain

The phenomenon in which demand variability increases as one moves upstream in the supply chain has been often observed in practice. This so-called “bullwhip effect” often increases upstream operations costs, including inventory holding and transportation costs. Price variations are considered to be one of the primary causes of the bullwhip effect, and thus everyday low price (EDLP) strategies are commonly recommended to counter the negative impacts of the bullwhip effect. However, trade promotions continue to play an important role in the U.S. supermarket industry as well as other industries. This paper investigates this apparent inconsistency between the literature and practice by employing a deterministic, two-stage supply chain model composed of a single supplier and a single retailer. We demonstrate that even though the use of trade promotions can indeed increase a retailer's and supplier's operations costs, these costs may be more than offset by increased revenues, even in the absence of explicit coordination. That is, if the supplier judiciously applies a trade promotion strategy and the retailer passes some of this discount to its customers, then under certain conditions, the resulting supply chain profit can exceed that under an EDLP strategy. We provide a broad set of computational results that validate this conclusion and discuss the resulting managerial insights.     

Stages of Supply Chain Disruption Response: Direct,Constraining, and Mediating Factors for Impact Mitigation

It is well established that supply chain disruptions can have a severe negative impact on firms and general wisdom suggests that this impact can be mitigated by quick responses. Aside from a few anecdotes, however, little is known about the decision‐making process that leads to speedy responses and about its impeding and supporting antecedents. Using the organizational information‐processing perspective, this empirical study unravels the disruption management process along a sequence of four stages—disruption recognition, disruption diagnosis, response development, and response implementation—and hypothesizes constraining and mediating effects of these stages. The findings contribute to an improved understanding of the role that the decision stages play in mitigating supply chain disruptions, and confirm the prediction that the speed with which information is processed and the stages are worked through positively affects supply chain performance. In addition, the findings suggest that one of the stages, diagnosis, acts as a constraining factor to the other stages. The stages also play a mediating role between the impact that the disruption has and a firm's readiness (prior to a disruption), dependence on a key supplier, and supply chain complexity. This provides guidance to decision makers in the application of resources both prior to a negative event and during a disruption recovery.     

A fair evaluation of certain stage in a two-stage structure: revisiting the typical two-stage DEA approaches

The efficiency of decision processes with a two-stage structure has been studied by some modified versions of Data Envelopment Analysis (DEA) methodology, such as the relational or centralized model, and the non-cooperative model. After revisiting the rationale of the centralized model provided by the literature, we find that some unfairness exist in its efficiency evaluation of certain stage. This unfairness leads to the usual underestimation of the overall efficiency by the centralized model. Furthermore, because the independent DEA model for one stage ignores its relation and coordination with the other stage and the two-stage system, externalities between these members may arise and lead to the seeming contradiction in efficiencies derived by independent DEA models for the stages and the black box system. Therefore, we argue that the efficiency of certain stage in the context of a two-stage structure should be reevaluated instead of simply using the independent DEA model. A sequence of leader-follower procedures, with data adjustment on intermediates, is proposed to eliminate the externalities and to ensure a fair evaluation. We find that, after this data adjustment, the reevaluation of the second stage for a given Decision Making Unit (DMU) yields the same result as obtained by the standard DEA model regarding the two-stage as a black box. Moreover, some explicit relations are established between the black box model, the centralized model, and the non-cooperative model. Two typical examples taken from the literature illustrate our main results. Our findings also imply that more emphasis should be placed on the game theoretic DEA approach to model the efficiency evaluation of two-stage processes.     

On the mod sum number of H m,n

Let N denote the set of all positive integers. The sum graph G ⁺(S) of a finite subset S?N is the graph (S,E) with uv∈E if and only if u+v∈S. A graph G is said to be an mod sum graph if it is isomorphic to the sum graph of some S?Z _M \{0} and all arithmetic performed modulo M where M≥|S|+1. The mod sum number ρ(G) of G is the smallest number of isolated vertices which when added to G result in a mod sum graph. It is known that the graphs H _m,n (n>m≥3) are not mod sum graphs. In this paper we show that H _m,n are not mod sum graphs for m≥3 and n≥3. Additionally, we prove that ρ(H _m,3)=m for m≥3, H _m,n ∪ρK ₁ is exclusive for m≥3 and n≥4 and $m(n-1) \leq \rho(H_{m,n})\leq \frac{1}{2} mn(n-1)$ for m≥3 and n≥4.     

A note on the annihilation number and 2-domination number of a tree

In 2014, Desormeaux et al. (Discrete Math 319:15–23, 2014) proved a relationship between the annihilation number and 2-domination number of a tree. In this note, we provide a family of bounds for the 2-domination number of a tree based on the amount of vertices of small degree. This family of bounds extends current bounds on the 2-domination number of a tree, and provides an alternative proof for the relationship between the annihilation number and the 2-domination number of a tree that was shown by Desormeaux et al.     

Attachment, social support, and responses following the death of a companion animal

This research tested hypotheses concerning attachment, social support, and grief responses to the loss of animal companionship. Participants whose companion cat or dog had recently died (N = 429) completed the Attachment Style Questionnaire, the Inventory of Complicated Grief, and the Multidimensional Health Profile-Psychosocial Functioning questionnaires. Both attachment anxiety and attachment avoidance were found to be positively associated with respondents' grief, depression, anxiety, and somatic symptoms. Social support was found to be negatively associated with these outcomes as well as with attachment anxiety and attachment avoidance. In multiple regression analyses, attachment anxiety incrementally predicted grief, anxiety and somatic symptoms, attachment avoidance incrementally predicted grief and depression, and social support incrementally predicted all outcomes. Interaction effects of attachment and social support in relation to outcomes were not found. The present study's implications and limitations are discussed, as are directions for future research.     

The number of edges,spectral radius and Hamilton-connectedness of graphs

In this paper, we prove that a simple graph G of order sufficiently large n with the minimal degree \(\delta (G)\ge k\ge 2\) is Hamilton-connected except for two classes of graphs if the number of edges in G is at least \(\frac{1}{2}(n^2-(2k-1)n + 2k-2)\). In addition, this result is used to present sufficient spectral conditions for a graph with large minimum degree to be Hamilton-connected in terms of spectral radius or signless Laplacian spectral radius, which extends the results of (Zhou and Wang in Linear Multilinear Algebra 65(2):224–234, 2017) for sufficiently large n. Moreover, we also give a sufficient spectral condition for a graph with large minimum degree to be Hamilton-connected in terms of spectral radius of its complement graph.     

Measurement of tourist hotels׳ productive efficiency,occupancy, and catering service effectiveness using a modified two-stage DEA model in Taiwan

This study develops a modified two-stage model to evaluate productive efficiency, occupancy, and catering service effectiveness of Taiwan׳s international tourist hotels. The difference between the modified and original two-stage model is that the modified two-stage model allows for multiple efficiencies to be calculated in the unique stage and the concept of intermediate input is introduced.The modified model was tested using 58 Taiwanese international hotels and the results show the modified model offers a more efficient and effective approach in calculating all the efficiencies in a single data envelopment analysis (DEA) implementation as opposed to independent efficiency calculations.     

Leadership skills and the group performance: Situational demands,behavioral requirements,and planning

In recent years, the role of cognitive skills in shaping leader performance has received more attention. In the present study, the role of one key set of skills, planning skills, was examined with respect to leader emergence and group performance in a sample of 55 groups, containing 195 undergraduates, working on a business planning task. Leader planning skills were assessed along with structuring and considerate behavior under conditions where task complexity, group diversity, and turbulence were examined as potential influences on the need for planning and the need for leaders possessing planning skills. It was found that complexity, diversity, and turbulence influenced the quality and originality of group plans, as well as structuring behavior on the part of leaders. Leader structuring behavior interacted with leader planning skills in determining the quality and originality of group plans. The implications of these findings for understanding the role of planning skills in shaping leader emergence and group performance are discussed.     

不打不成器:挖掘辱虐管理的正效应、负效应和净效应

辱虐管理一直是负面组织行为的研究热点,近年呈现一些新趋势,特别是在崇尚“不打不成器”的本土情境下,挑战视之为“绝对恶魔”的呼声渐起。理论创始人Tepper也呼吁进行更多的研究来比较与整合其正面和负面效应。摒弃已有研究忽视辱虐管理主观目的性的研究惯例,从概念本源出发,整合感知控制理论与有限控制理论双重线索,探讨了辱虐管理与下属绩效的倒U型关系及其成因。453份配对样本的Fieller法和J-N法检验结果支持了倒U型假设,并揭示辱虐管理对下属自我努力有凹型影响,较大程度上促进下属的纠偏努力,对自我损耗有凸型影响,加剧损耗;正负效应的叠加导致倒U型净效应出现。研究结果有助于深化辱虐管理影响机制研究,也有助于丰富和拓展非线性方法研究。     

Chromatic number of distance graphs generated by the sets {2,3,x,y}

Let D be a set of positive integers. The distance graph generated by D has all integers ? as the vertex set; two vertices are adjacent whenever their absolute difference falls in D. We completely determine the chromatic number for the distance graphs generated by the sets D={2,3,x,y} for all values x and y. The methods we use include the density of sequences with missing differences and the parameter involved in the so called “lonely runner conjecture”. Previous results on this problem include: For x and y being prime numbers, this problem was completely solved by Voigt and Walther (Discrete Appl. Math. 51:197–209, 1994); and other results for special integers of x and y were obtained by Kemnitz and Kolberg (Discrete Math. 191:113–123, 1998) and by Voigt and Walther (Discrete Math. 97:395–397, 1991).     

Coordination of teams,meetings, and managerial processes in construction projects: using a lean and complex adaptive mechanism

In a construction project, the ‘production planning and control’ function drives the deployment of construction operations. A reliable function is therefore essential. Currently, this function is supplied using economic/contractual and production processes. This approach, however, disregards the explicit regulation of teams, meetings, and the linkages between the function’s elements. Using Lean Management and Complexity theories, we studied a mechanism to address this issue. Using data from an 18-storey building construction project in a case study, this paper analyses a prototype system for driving the function using their linkages. A questionable behaviour beyond the function’s capability was found. This behaviour involves complex, flexible, and push features, focused on execution, where the linkages driven by teams, meetings and processes cause variation from 10% up to 54% in the failure reasons, the progress, and the reliability. These findings suggest a function driven by its complexity level. These new insights require further study.     

Development and implementation of a knowledge-based system for the dynamic scheduling of a two-stage production process

Abstract

This paper discusses the implementation of a knowledge-based system for the dynamic scheduling of a two-stage production process. It is an interactive, real-time, menu-driven system written in Prolog. The system architecture is delineated and the rules and problem-solving logic to be used under various dynamic situations are described. Results of a sample system test session are included to illustrate its use.