The impact of a waiting-time threshold in overflow systems with impatient customers

This paper analyzes the performance of call centers with impatient customers, two levels of support, and an overflow mechanism. Waiting calls from the front-office queue – if not reneging – are sent to the back office if at least one back-office agent is available and if a certain threshold t on the waiting time is reached. We approximate such systems via a continuous-time Markov chain that allows for overflow immediately upon arrival. Two different approaches for the derivation of the respective probability of an overflow are developed. Numerical results compare the reliability of these Markovian performance approximations for different parameter settings. The impact of the threshold t on different performance measures is shown dependent on the impatience of customers.     

Ein heuristisches Modell zur Work-Life-Balance: Vier Dimensionen des Tätigseins

The author picks up a model of the philosopher Martin Seel on the ?four dimensions of activity“ in human life, and he develops a pragmatic concept of work-life-balance. These dimensions are: (1) Work as purposeful activity, (2) interaction as dealing with a human other, (3) play as activity which has the purpose in itself, (3) contemplation as non-dialogical interaction with an object. After some considerations on the postmodern working culture and on the concept of work-life-balance, these dimensions are delineated in detail and explained in their relatedness. Successful life requires that all dimensions are available. A questionnaire may help a coachee to reconsider and eventually to modify his life style.     

Two-stage time minimizing assignment problem

This paper deals with the optimal selection of m out of n facilities to first perform m   given primary jobs in Stage-I followed by the remaining (n-m)$(n-m)$ facilities performing optimally the (n-m)$(n-m)$ secondary jobs in Stage-II. It is assumed that in both the stages facilities perform in parallel. The aim of the proposed study is to find that set of m   facilities performing the primary jobs in Stage-I for which the sum of the overall completion times of jobs in Stage-I and the corresponding optimal completion time of the secondary jobs in Stage-II by the remaining (n-m)$(n-m)$ facilities is the minimum. The developed solution methodology involves solving the standard time minimizing and cost minimizing assignment problems alternately after forbidding some facility-job pairings and suggests a polynomially bound algorithm. This proposed algorithm has been implemented and tested on a variety of test problems and its performance is found to be quite satisfactory.     

A critical review of race and ethnicity in the leadership literature: Surfacing context,power and the collective dimensions of leadership

Leadership studies focusing on race–ethnicity provide particularly rich contexts to illuminate the human condition as it pertains to leadership. Yet insights about the leadership experience of people of color from context-rich research within education, communications and black studies remain marginal in the field. Our framework integrates these, categorizing reviewed studies according to the effects of race–ethnicity on perceptions of leadership, the effects of race–ethnicity on leadership enactments, and actors' approach to the social reality of race–ethnicity. The review reveals a gradual convergence of theories of leadership and theories of race–ethnicity as their relational dimensions are increasingly emphasized. A shift in the conceptualization of race–ethnicity in relation to leadership is reported, from a constraint to a personal resource to a simultaneous consideration of its constraining and liberating capacity. Concurrent shifts in the treatment of context, power, agency versus structure and causality are also explored, as are fertile areas for future research.     

No place to go? Management of non-human animal overflows in Australia

I discuss overflows of several introduced vertebrate species in Australia and critically explore their construction as national pests – overflows - appropriate for management by lethal control. I outline the thanato-politics and thanato-economics of managing selected non-human animals by toxic baiting and/or viral infection in ecologies of toxicity and the trophic cascades which may ensue. Drawing on Foucault and Deleuze, I explore creative potentialities for conservation managers of thinking in terms of milieu and environnementalité; exploration of the conditions of possibility for non-human animals to live in their milieus, considering relationalities with elements such as habitat fragmentation, fire regimes, pesticide use and so on. This could form a biopolitics which relocates biopower to within the subject rather than a thanato-politics of overflow, surplus and death.     

Validation of immigrants’ prior foreign learning as a framing practice

This paper explores the attempts by public officials and caseworkers to manage an overflow of immigrants in the labour market in Sweden. I draw on notions of framing and overflowing, inspired by Michel Callon's (1998) work on the organizing of market-based exchange relationships. I argue that validation is best understood as a framing practice, aimed at creating an understanding for the vastness of foreign experience – including skills and competence – of recent immigrants to Sweden, to make this experience measurable and manageable. Validation as a framing practice thereby exemplifies the widespread trust in framing as a way to normalise overflows – to turn overflows into normal flows. However, as the ethnography-inspired study reported here shows, repeated framing does not remove overflows; instead, it produces new and different types of overflows. In the conclusions, I emphasise the heavy investments required by validation in contrast with the fragility of the results it produces in the context of migration management.     

The Potential Effects of Recall Bias and Selection Bias on the Epidemiological Evidence for the Carcinogenicity of Glyphosate

Glyphosate is a widely used herbicide worldwide. The International Agency for Research on Cancer in 2015 declared that glyphosate is probably carcinogenic to humans, noting a positive association for non-Hodgkin lymphoma (NHL). The principal human data on glyphosate and NHL come from five case–control studies and two cohort studies. The case–control studies are at risk of recall bias resulting from information on exposure to pesticides being collected from cases and controls based on their memories. In addition, two of the case–control studies are additionally at risk of a form of selection bias that can exacerbate the effect of recall bias. Both biases are in the direction of making glyphosate appear carcinogenic. If odds ratios (ORs) are not biased and a pesticide plays no role in causing NHL, the probability that an OR for that pesticide is greater than 1.0 is approximately 0.5. The fractions of ORs for pesticides other than glyphosate that are greater than 1.0 in the case–control studies are 0.90 (n = 92), 0.90 (n = 152), 0.93 (n = 59), 0.76 (n = 140), and 0.53 (n = 54), the first two from studies that are at risk for both types of bias. In the two cohort studies, which are not subject to these biases, the comparable fractions for relative risks for all cancers are 0.51 (n = 70) and 0.48 (n = 158). These results comply closely with what would be expected if evidence for carcinogenicity of glyphosate in these studies results from statistical bias in the case–control studies.     

The role of leaders in inducing and maintaining cooperation: The CC strategy

I discuss recent findings from behavioral economic experiments in the lab and in the field on the role of leaders in human cooperation. Three implications for leadership are derived, which are summarized under the notion CC strategy. Firstly, leaders need to trust to not demotivate the motivated. Secondly, leaders need to punish to motivate the non-motivated. Finally, leaders shall (and can) attract motivated types. The discussion is embedded in a more general attempt to promote and stimulate interdisciplinary exchange of both methods and ideas in leadership research.     

Paired versus double domination in K 1,r -free graphs

A vertex in G is said to dominate itself and its neighbors. A subset S of vertices is a dominating set if S dominates every vertex of G. A paired-dominating set is a dominating set whose induced subgraph contains a perfect matching. The paired-domination number of a graph G, denoted by γ _pr(G), is the minimum cardinality of a paired-dominating set in G. A subset S?V(G) is a double dominating set of G if S dominates every vertex of G at least twice. The minimum cardinality of a double dominating set of G is the double domination number γ _×2(G). A claw-free graph is a graph that does not contain K _1,3 as an induced subgraph. Chellali and Haynes (Util. Math. 67:161–171, 2005) showed that for every claw-free graph G, we have γ _pr(G)≤γ _×2(G). In this paper we extend this result by showing that for r≥2, if G is a connected graph that does not contain K _1,r as an induced subgraph, then $\gamma_{\mathrm{pr}}(G)\le ( \frac{2r^{2}-6r+6}{r(r-1)} )\gamma_{\times2}(G)$ .     

The broadcast median problem in heterogeneous postal model

We propose the problem of finding broadcast medians in heterogeneous networks. A heterogeneous network is represented by a graph G=(V,E), in which each edge has a weight that denotes the communication time between its two end vertices. The overall delay of a vertex v∈V(G), denoted as b(v,G), is the minimum sum of the communication time required to send a message from v to all vertices in G. The broadcast median problem consists of finding the set of vertices v∈V(G) with minimum overall delay b(v,G) and determining the value of b(v,G). In this paper, we consider the broadcast median problem following the heterogeneous postal model. Assuming that the underlying graph G is a general graph, we show that computing b(v,G) for an arbitrary vertex v∈V(G) is NP-hard. On the other hand, assuming that G is a tree, we propose a linear time algorithm for the broadcast median problem in heterogeneous postal model.     

On the etiology of conflict cultures

Conflict has long been conceived as a fundamental part of all organizational systems. Yet the literature on conflict is largely divorced from its organizational roots and instead focuses on general processes of conflict management at the individual and small group levels of analysis. To re-establish the organizational basis of conflict, we develop a macro-theory of conflict cultures, or shared norms that specify how conflict should be managed in organizational settings. We propose a typology of conflict cultures that draws upon two dimensions – active versus passive conflict management norms and agreeable versus disagreeable conflict management norms – and discuss the etiology of four distinct conflict cultures: dominating conflict cultures (active and disagreeable), collaborative conflict cultures (active and agreeable), avoidant conflict cultures (passive and agreeable), and passive–aggressive conflict cultures (passive and disagreeable). We discuss top-down processes (e.g., leadership, organizational structure and rewards, industry, community, and societal factors) and bottom-up processes (e.g., personality, demographics, values and social networks) through which these conflict cultures develop. We explore both positive and negative organizational outcomes associated with each conflict culture, as well as moderators of proposed effects. We conclude with theoretical, practical, and empirical implications of a conflict culture perspective.     

“It's not how it looks!” Exploring managerial perspectives on employee wellbeing

The literature on employee wellbeing (EW) has largely focussed on employees' subjective experiences and has generally assumed that managers’ interpretations of EW are consistent and non-problematic. Tensions inherent in managing complex expectations, and diverse results, have not been adequately investigated, and ways in which EW practices are viewed by senior managers have not been sufficiently examined. This paper attempts to fill this gap by exploring the perceptions of senior managers with human resources (HR) responsibilities affecting EW. There is a specific focus on the tensions experienced by these senior managers and the related tactics they adopted to successfully manage them. We gathered data from focus groups made up of 20 senior managers from companies operating in the Milan County in Italy. An analysis of this data identified four predominant dimensions of EW, as well as the tensions felt by the managers and the various tactics they used to overcome them. Finally, we classified the interpretative tactics into four broad resolution strategies (i.e. flexible, integrative, separated and reciprocal thinking) that senior managers adopted to cognitively address their experience of tensions.     

Fleeing from the Elephant

Abstract

The present set of papers show that leaders in the field of organizational behavior management are grappling with issues of human language and cognition. That is a good and necessary step for the field, but the solutions proposed are worrisome: adopting principles from non-behavioral psychology, adopting principles from introspection that have not been empirically validated, returning to methodological behaviorism, or appealing to non-empirical interpretations using traditional behavioral principles. In this paper I argue that these are the wrong solutions, being taken for the right reasons. There is a need for an analysis of language and cognition, but it will be found neither in other forms of psychology nor in traditional Skinnerian thinking on the topic. I suggest instead that OBM look at the data that exists in contemporary basic behavior analysis on the topic, particularly in the area of Relational Frame Theory. That work is a vigorous area of research, and its applied implications are significant, growing, and known to be relevant to organizations. The solution to the malaise these papers reflect is most likely to be found in post-Skinnerian behavior analysis itself.     

The total {k}-domatic number of wheels and complete graphs

Let k be a positive integer and let G be a graph with vertex set V(G). The total {k}-dominating function (T{k}DF) of a graph G is a function f from V(G) to the set {0,1,2,??,k}, such that for each vertex v??V(G), the sum of the values of all its neighbors assigned by f is at least k. A set {f ₁,f ₂,??,f _d } of pairwise different T{k}DFs of G with the property that $\sum_{i=1}^{d}f_{i}(v)\leq k$ for each v??V(G), is called a total {k}-dominating family (T{k}D family) of G. The total {k}-domatic number of a graph G, denoted by $d_{t}^{\{k\}}(G)$ , is the maximum number of functions in a T{k}D family. In this paper, we determine the exact values of the total {k}-domatic numbers of wheels and complete graphs, which answers an open problem of Sheikholeslami and Volkmann (J. Comb. Optim., 2010) and completes a result in the same paper.     

Note on “The Backroom Effect in Retail Operations”

Eroglu et al. (2013) study a retailer with limited shelf capacity and a backroom. They study a continuous review (r, q) ordering policy with a known order quantity, q. Assuming that backorders can be satisfied from the backroom inventory (if available), they find the expression for the optimal reorder level, r. Our work builds on Eroglu et al. (2013). We correct an erroneous derivation of the expected overflow term, as well as derive an exact expression for the expected cost function, and hence optimal reorder level, instead of the approximate one used by Eroglu et al. (2013).     

Dealing with too much

In the paper, I address three issues that were often missing in the discussion of overflow: (1) A large quantity (of objects, information, etc.) is a condition that is necessary, but not sufficient for feeling overwhelmed; (2) Dealing with a large amount of incoming information is easier if we use subjectively unquestionable (because shared with other people) criteria; (3) The length of exposure to overflow of information. I present the results of analyses that support the role of motivation and shared values in feeling overwhelmed. I also discuss the individual differences in dealing with overflow, as some of us cope with “too much” better than others.     

The cost of selfishness for maximizing the minimum load on uniformly related machines

Consider the following scheduling game. A set of jobs, each controlled by a selfish agent, are to be assigned to m uniformly related machines. The cost of a job is defined as the total load of the machine that its job is assigned to. A job is interested in minimizing its cost, while the social objective is maximizing the minimum load (the value of the cover) over the machines. This goal is different from the regular makespan minimization goal, which was extensively studied in a game theoretic context. We study the price of anarchy (poa) and the price of stability (pos) for uniformly related machines. The results are expressed in terms of s, which is the maximum speed ratio between any two machines. For uniformly related machines, we prove that the pos is unbounded for s>2, and the poa is unbounded for s≥2. For the remaining cases we show that while the poa grows to infinity as s tends to 2, the pos is at most 2 for any s≤2.     

Path packing and a related optimization problem

Let G be a supply graph, with the node set N and edge set E, and (T,S) be a demand graph, with T?N, S∩E=?. Observe paths whose end-vertices form pairs in S (called S-paths). The following path packing problem for graphs is fundamental: what is the maximal number of S-paths in G? In this paper this problem is studied under two assumptions: (a) the node degrees in N?T are even, and (b) any three distinct pairwise intersecting maximal stable sets A,B,C of (T,S) satisfy A∩B=B∩C=A∩C (this condition was defined by A. Karzanov in Linear Algebra Appl. 114–115:293–328, 1989). For any demand graph violating (b) the problem is known to be NP-hard even under (a), and only a few cases satisfying (a) and (b) have been solved. In each of the solved cases, a solution and an optimal dual object were defined by a certain auxiliary “weak” multiflow optimization problem whose solutions supply constructive elements for S-paths and concatenate them into an S-path packing by a kind of matching. In this paper the above approach is extended to all demand graphs satisfying (a) and (b), by proving existence of a common solution of the S-path packing and its weak counterpart. The weak problem is very interesting for its own sake, and has connections with such topics as Mader’s edge-disjoint path packing theorem and b-factors in graphs.