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.     

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.     

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.     

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.     

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).     

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.     

The pros and cons of drug testing in the business sector

The public policy issues of whether society should permit the business sector to test for the presence of illegal drug use by the employees is one in which seemingly convincing arguments can be advanced to support self-policing in this area as well as equally cogent arguments erected against the concept of empowering the corporate sector, to investigate the presumably enact sanctions against employee illegal drug usage.In this paper the authors will attempt to explore the controversy from several different scholarly perspectives, analyzing the most important arguments both for and against permitting the corporate sector to engage in employee drug testing. In criticizing each argument we will attempt to explicate the salient public policy implications, business effects and unique ethical issues that will have profound ramifications upon the larger society. In addition, we will analyze the current legal status of this controversy, citing the applicable controlling cases at the Federal level. Finally, the authors will give their policy recommendations based upon their analysis of the discussion in this paper.The authors believe it would be most advantageous to facilitate this discussion by first considering the arguments for permitting the corporate sector to engage in drug-testing employees for illegal substances, and then consider the arguments against permitting corporate drug-testing.     

Management innovation,pro-innovation organisational culture and enterprise performance: testing the mediation effect

The interest in management innovation (MI) is growing and the conviction about its significant role in boosting an enterprise’s competitive advantage and performance has recently gained ground. The studies on MI and its relationships with enterprise performance, which are relatively scarce in literature, indicate the complexity of these relationships. This inspired us to propose the management innovation construct and its operationalisation, which allowed for the empirical verification of the relationships between management innovation and enterprise performance. Simultaneously, we adopted the hypothesis on the mediating role of pro-innovation organisational culture. The aim of this article, therefore, is to study the relationships between MI and enterprise performance as well as to determine what role is played by pro-innovation organisational culture in these relationships. In order to do that, we conducted a survey of 301 companies based in Poland. Our research results confirmed the existence of relationships between management innovation and enterprise performance in the survey sample, although they were not very strong. Additionally, the hypothesis about the mediating role of organisational culture was also partially supported. The results of our study enrich the knowledge about the role of MI in stimulating enterprise performance and the role of pro-innovation organisational culture. We also discuss the implications for further research and management practice.     

Leadership behaviors and group creativity in Chinese organizations: The role of group processes

In seeking to understand the factors contributing to work group creativity in Chinese organizations, we explored the roles of two different leadership styles (transformational and authoritarian) that Chinese leaders play in group creativity through influencing internal group processes, i.e., collective efficacy and knowledge sharing among group members. We tested our hypotheses with a sample of 163 work groups involving 973 employees in twelve Chinese companies. We found transformational leadership to relate positively but authoritarian leadership to relate negatively to group creativity, mediated by both collective efficacy and knowledge sharing among members within the group. We discuss the implications of these findings for research on group leadership, group creativity and cross-cultural management.     

The role of leadership self-efficacy and stereotype activation on cardiovascular,behavioral and self-report responses in the leadership domain

This research examines female leaders' responses to the gender–leader stereotype and the role of leadership self-efficacy in these responses. Using the biopsychosocial model of threat and challenge, this laboratory experiment examined women's cardiovascular, behavioral (i.e., performance), and self-report responses to the negative female leader stereotype as a function of leadership efficacy. Female participants, selected on leadership efficacy scores, served as leaders of ostensible three-person groups within an immersive virtual environment. Half were explicitly primed with the negative stereotype. As predicted, women with high, as opposed to low, percepts of leadership self-efficacy exhibited cardiovascular patterns of threat when performing the leadership task, and they performed better in the explicit stereotype activation condition compared to those not explicitly primed. Additionally, this threat was consistent with positive reactance responses on behavioral and self-report measures. Low efficacy leaders were not threatened, but they did show stereotype priming effects by assimilating to the negative stereotype on the self-report and behavioral measures. This research provides greater insight into stereotype reactance effects and highlights the role of self-efficacy in moderating stereotype threat and stereotype priming effects.     

Part 2, Conflict management. How to shape positive relationships in medical practices and hospitals

Managing workplace conflict is one of the most important, stressful, and time-consuming tasks faced by today's physician leaders. In Part 1 of this article series, the authors describe how to assess an organization's interpersonal dynamics. True change comes from interventions that help an organization to become a positive interpersonal culture, one that fosters cooperation and collaboration. Part 2 offers seven steps to solving the disruptive physician problem: (1) provide protection to complainants; (2) listen, empathize, and avoid communication triangles; (3) confront offenders with data, authority, and compassion; (4) if needed, get outside help; (5) offer workplace training and experiences that foster positive relationships; (6) follow-up; and (7) practice what you preach. The self-assessment and intervention guidelines discussed in this series of articles can help physician executive move beyond struggling with episodes of conflict to shaping stress-resilient medical organizations.