Nordhaus–Gaddum type result for the matching number of a graph

For a graph G, \(\alpha '(G)\) is the matching number of G. Let \(k\ge 2\) be an integer, \(K_{n}\) be the complete graph of order n. Assume that \(G_{1}, G_{2}, \ldots , G_{k}\) is a k-decomposition of \(K_{n}\). In this paper, we show that (1)

$$\begin{aligned} \left\lfloor \frac{n}{2}\right\rfloor \le \sum _{i=1}^{k} \alpha '(G_{i})\le k\left\lfloor \frac{n}{2}\right\rfloor . \end{aligned}$$

(2) If each \(G_{i}\) is non-empty for \(i = 1, \ldots , k\), then for \(n\ge 6k\),

$$\begin{aligned} \sum _{i=1}^{k} \alpha '(G_{i})\ge \left\lfloor \frac{n+k-1}{2}\right\rfloor . \end{aligned}$$

(3) If \(G_{i}\) has no isolated vertices for \(i = 1, \ldots , k\), then for \(n\ge 8k\),

$$\begin{aligned} \sum _{i=1}^{k} \alpha '(G_{i})\ge \left\lfloor \frac{n}{2}\right\rfloor +k. \end{aligned}$$

The bounds in (1), (2) and (3) are sharp. (4) When \(k= 2\), we characterize all the extremal graphs which attain the lower bounds in (1), (2) and (3), respectively.

     

On Motzkin–Straus type results for non-uniform hypergraphs

Recently, some extensions of Motzkin–Straus theorems were proved for non-uniform hypergraphs whose edges contain 1 or r vertices in Gu et al. (J Comb Optim 31:223–238, 2016), Peng et al. (Discret Appl Math 200:170–175, 2016a), where r is a given integer. It would be interesting if similar results hold for other non-uniform hypergraphs. In this paper, we establish some Motzkin–Straus type results for general non-uniform hypergraphs. In particular, we obtain some Motzkin–Straus type results in terms of the Lagrangian of non-uniform hypergraphs when there exist some edges consisting of 2 vertices in the given hypergraphs. The presented results unify some known Motzkin–Straus type results for both uniform and non-uniform hypergraphs and also provide solutions to a class of polynomial optimization problems over the standard simplex in Euclidean space.     

Some Motzkin–Straus type results for non-uniform hypergraphs

A remarkable connection between the order of a maximum clique and the Lagrangian of a graph was established by Motzkin and Straus in 1965. This connection and its extensions were applied in Turán problems of graphs and uniform hypergraphs. Very recently, the study of Turán densities of non-uniform hypergraphs has been motivated by extremal poset problems. Peng et al. showed a generalization of Motzkin–Straus result for \(\{1,2\}\)-graphs. In this paper, we attempt to explore the relationship between the Lagrangian of a non-uniform hypergraph and the order of its maximum cliques. We give a Motzkin–Straus type result for \(\{1,r\}\)-graphs. Moreover, we also give an extension of Motzkin–Straus theorem for \(\{1, r_2, \cdots , r_l\}\)-graphs.     

The competition number of a graph with?exactly?two?holes

Given an acyclic digraph D, the competition graph C(D) of D is the graph with the same vertex set as D and two distinct vertices x and y are adjacent in C(D) if and only if there is a vertex v in D such that (x,v) and (y,v) are arcs of D. The competition number κ(G) of a graph G is the least number of isolated vertices that must be added to G to form a competition graph. The purpose of this paper is to prove that the competition number of a graph with exactly two holes is at most three.     

Development and application of a dose–response model for Elizabethkingia spp

Elizabethkingia spp. are common environmental pathogens responsible for infections in more vulnerable populations. Although the exposure routes of concern are not well understood, some hospital-associated outbreaks have indicated possible waterborne transmission. In order to facilitate quantitative microbial risk assessment (QMRA) for Elizabethkingia spp., this study fit dose–response models to frog and mice datasets that evaluated intramuscular and intraperitoneal exposure to Elizabethkingia spp. The frog datasets could be pooled, and the exact beta-Poisson model was the best fitting model with optimized parameters α  = 0.52 and β = 86,351. Using the exact beta-Poisson model, the dose of Elizabethkingia miricola resulting in a 50% morbidity response (LD₅₀) was estimated to be approximately 237,000 CFU. The model developed herein was used to estimate the probability of infection for a hospital patient under a modeled exposure scenario involving a contaminated medical device and reported Elizabethkingia spp. concentrations isolated from hospital sinks after an outbreak. The median exposure dose was approximately 3 CFU/insertion event, and the corresponding median risk of infection was 3.4E-05. The median risk estimated in this case study was lower than the 3% attack rate observed in a previous outbreak, however, there are noted gaps pertaining to the possible concentrations of Elizabethkingia spp. in tap water and the most likely exposure routes. This is the first dose–response model developed for Elizabethkingia spp. thus enabling future risk assessments to help determine levels of risk and potential effective risk management strategies.     

Hardness results and approximation algorithm for total liar’s domination in graphs

In this paper, we initiate the study of total liar’s domination of a graph. A subset L?V of a graph G=(V,E) is called a total liar’s dominating set of G if (i) for all v∈V, |N _G (v)∩L|≥2 and (ii) for every pair u,v∈V of distinct vertices, |(N _G (u)∪N _G (v))∩L|≥3. The total liar’s domination number of a graph G is the cardinality of a minimum total liar’s dominating set of G and is denoted by γ _TLR (G). The Minimum Total Liar’s Domination Problem is to find a total liar’s dominating set of minimum cardinality of the input graph G. Given a graph G and a positive integer k, the Total Liar’s Domination Decision Problem is to check whether G has a total liar’s dominating set of cardinality at most k. In this paper, we give a necessary and sufficient condition for the existence of a total liar’s dominating set in a graph. We show that the Total Liar’s Domination Decision Problem is NP-complete for general graphs and is NP-complete even for split graphs and hence for chordal graphs. We also propose a 2(lnΔ(G)+1)-approximation algorithm for the Minimum Total Liar’s Domination Problem, where Δ(G) is the maximum degree of the input graph G. We show that Minimum Total Liar’s Domination Problem cannot be approximated within a factor of $(\frac{1}{8}-\epsilon)\ln(|V|)$ for any ?>0, unless NP?DTIME(|V|^loglog|V|). Finally, we show that Minimum Total Liar’s Domination Problem is APX-complete for graphs with bounded degree 4.     

Bounding the total domination subdivision number of a graph in terms of its order

The total domination subdivision number \(\mathrm{sd}_{\gamma _{t}}(G)\) of a graph G is the minimum number of edges that must be subdivided (each edge in G can be subdivided at most once) in order to increase the total domination number. In this paper we prove that \(\mathrm{sd}_{\gamma_{t}}(G)\leq \lfloor\frac{2n}{3}\rfloor\) for any simple connected graph G of order n≥3 other than K ₄. We also determine all simple connected graphs G with \(\mathrm{sd}_{\gamma_{t}}(G)=\lfloor\frac{2n}{3}\rfloor\).     

Designing a Decision-Making Process for a Network Administrative Organization: A Case Study of the National Quality Forum’s Consensus Development Process

In 1999 the health care industry created the National Quality Forum—a network administrative organization—to address issues of health care quality in a new way by bringing together organizations from the public and private sectors and providing them with a forum to discuss and debate measures of quality, and ultimately, to effect change. Little, however, is known about the decision making processes of network administrative organizations despite the fact that their decisions may have far-reaching impacts on public policy. Using a grounded theory approach, this paper examines the creation and development of the NQF’s Consensus Development Process and identifies and discusses five key principles that underlie the process. This paper argues that in order to create a decision-making process for a network administrative organization that is balanced and inclusive of diverse interests a leader must consider and incorporate principles that are representative of the larger environment.     

Value–value load diagram: a graphical tool for lean–green performance assessment

Integrated assessment of operational and environmental performance of the production system requires mapping of all the processes and activities in the form of their resource utilisation efficiency. Prior research indicates that most lean assessment tools and techniques have studied operational dimensions ignoring environmental aspect as a part of the assessment tool. Moreover, movement towards the greener production system has become a key strategic consideration for organisations to maintain a competitive edge and to remain as market winners. Continuous assessment in both, lean and green, dimensions is crucial in improving the overall performance through efficient utilisation of the available resources. In lean environment, value stream mapping (VSM) allows assessment of operational performance through identification of non-value adding activities in time units but fails to integrate inefficiencies related to material and energy utilisation. The tool-like material flow cost accounting (MFCA) is able to assess the environmental performance through physical and monetary evaluation of material flow within the production system. This paper presents, a novel tool, value–value load diagram (VVLD), for modelling and evaluating the operational (lean) and environmental (green) performance of the production system. VVLD graphically represents resource consumption, value addition and performance improvement opportunities within the production system by integrating VSM, MFCA and pinch analysis methodology. VVLD permits evaluation of the lean–green performance in terms of the eco-leanness index and also exposes the improvement opportunities by pinch point location. Some common generic scenarios for improvement in the eco-leanness index are demonstrated using VVLD. Application of VVLD along with the developed computer-based support system (CBSS) is demonstrated for a manufacturing SME in India, allowing the managers to evaluate and tune their processes for improved resource utilisation efficiency.     

Latour and Woolgar’s ‘cycle of scientific credibility’ as a basis for conceptualizing business school strategy

Review of Managerial Science - Drawing on contemporary and historical discourse around UK business schools and insights from the sociology of scientific knowledge, we argue that business schools...     

Uncertainty in competitive bidding – a framework for product–service systems

Owing to servitisation, manufacturing companies are increasingly required to compete through the provision of services around their products. The contracts for these services are often allocated through competitive bidding where the potential suppliers submit a price bid to the customer. The pricing decision is influenced by various uncertainties. This article proposes a conceptual framework depicting these influencing uncertainties on the bidding strategy. This framework is based on three empirical studies with industry investigating different viewpoints on the decision-making process. The intention is to support the pricing decision when competitively bidding for a service contract. The framework can be applied to specific competitive bidding situations to identify the influencing uncertainties, model them and depict their influences on the pricing decision.     

Green and lean: a Gemba–Kaizen model for sustainability enhancement

Abstract

Despite the encouraging results obtained from the application of Green Lean, organizations have found the integration of Green and Lean, and their implementation as an integrated approach, challenging. This paper therefore presents a model for integrating Lean and Green based on the Gemba-Kaizen approach. The proposed model was developed on the basis of a through literature review on Gemba and Kaizen, conducted on peer reviewed journal articles and pragmatic books, and the more than 40 years of accumulated experience of the authors as academics, researchers, industrialists and consultants. The model was validated through two cases study in the aerospace and automotive industries. The results showed that the proposed model helped the case organizations to reduce the consumption of resources and improve their environmental performance. The proposed model can be the basis for further research on Lean and Green, contributing to help organizations to improve their sustainability performance.     

The how and why of a firm’s approach to CSR and sustainability: a case study of a large European company

This paper aims to analyse “how” and “why” a company engages in CSR and sustainability. The “how” concerns the features of the firm’s CSR and sustainability approach, defined in terms of a firm’s strategy (implemented issues, initiatives and activities) and organization (organizational structures and roles and managerial systems adopted). The “why” refers to the key determinants, both internal and external, of CSR and sustainability. Finally, how the firm’s CSR and sustainability approach evolves over time and the relation between CSR determinants in various stages of the CSR evolutionary path are also investigated. The research method is based on the longitudinal analysis of a case study concerning a large multinational company operating in the telecommunications industry in Europe. The analysis of the case study shows that sub-cultural differences in the approach to CSR and sustainability may occur across hierarchical levels and functional units. Moreover, embedding CSR and sustainability principles doesn’t follow a linear and continuous process, made by sequential stages. Indeed, it can be characterized by an up and down evolutionary path, based on different stages with a changing emphasis given to CSR and sustainability issues. Finally, we find that the firm CSR and sustainability approach is not an autonomous choice, but it is a consequence of the contingent role played by both the external and the internal drivers and by their relative importance during the company’s CSR history.     

Accountability and value for money: a theoretical framework for the relationship in public–private partnerships

There is an implicit assumption in the UK Treasury’s publications on public-private partnerships (PPP)—also more commonly known in the United Kingdom as private finance initiative (PFI)—that accountability and value for money (VFM) are related concepts. While recent academic studies on PPP/PFI (from now on as PFI) have focused on VFM, there is a notable absence of studies exploring the ‘presumed’ relationships between accountability and VFM. Drawing on Dubnick’s (Dubnick and Romzek in American public administration, politics and the management of expectations. Macmillan, New York, 1991, Research in public administration. JAI, Greenwich, 1993; Dubnick in Public service ethics and the cultures of blame, 1996, Public sector ethics: finding and implementing values. Routledge, London, 1998, Int J Org Theory Behav 6(3):405–441, 2003, Public Perform Manage Rev 28(3):376–417, 2005; Dubnick and Justice in But can you trust them to be ethical, 2002) framework for accountability and PFI literature, we develop a research framework for exploring potential relationships between accountability and VFM in PFI projects by proposing alternative accountability cultures, processes and mechanisms for PFI. The PFI accountability model is then exposed to four criteria—warrantability, tractability, measurability and feasibility. Our preliminary interviews provide us guidance in identifying some of the cultures, processes and mechanisms indicated in our model which should enable future researchers to test not only the UK Government’s claimed relationships between accountability and VFM using more specific PFI empirical data, but also a potential relationship between accountability and performance in general.     

Time for a revival? Public policy implementation: a review of the literature and an agenda for future research

This paper argues that there is not a vigorous contemporary literature in the UK which addresses implementation studies as part of the public policy process, whereas this is not the case in the USA. A review of the literature is presented, and a critique of the more traditional thematic groupings used to review the literature is given. A revised thematic review of the literature is presented based on the four themes of: (1) the role of knowledge and learning in policy implementation; (2) the processes of policy implementation; (3) the role of actors and agents in implementation; and (4) the role of bureaucratic discretion. The paper argues for a revival of research into public policy implementation and suggests a research agenda for the future which can use the aforementioned themes from the literature.     

A short proof of a result on a Vizing-like problem for integer total domination

In this note, we provide a short proof of a recent result on a Vizing-like problem for integer total domination in graphs given by Li and Hou (J. Comb. Optim., 2008).     

Is health care ready for a full menu of prices?

Examine the emerging trend of price transparency in health care and learn what some states are doing to make prices widely available on the Web.     

Opportunism in buyer–supplier exchange: a critical examination of the concept and its implications for theory and practice

Abstract

Claims that opportunism is widespread in the process of buyer–supplier exchange are commonplace, but direct supporting evidence for such claims is largely absent from the relevant literature. This article offers a critique of the treatment of opportunism in supply chains by re-establishing the importance of guile in the concept and investigates existing published, empirical measures of buyer and supplier opportunistic behaviour. This article offers evidence that, despite the frequency with which the concept is discussed in the literature and applied in research and the emphasis given to the risks it generates for management, opportunism with guile between buyers and suppliers appears to be rare in practice. This article is the first critical assessment of the concept’s treatment in the Operations Management field, and it argues that practitioners are currently being poorly advised with respect to the phenomenon, as well as drawing conclusions for both practitioners and researchers that differ radically from the prevailing consensus on the subject.     

Transmission of a supplier’s disruption risk along the supply chain: a further investigation of the Chinese automotive industry

This paper primarily explores whether the transmission of a supplier’s disruption risk along the supply chain exists using a quantitative survey conducted in 31 Chinese automotive-related companies. Two downstream supply chain members are considered: manufacturer and distributor. Structural equation modelling is used. We find that both manufacturer and distributor can be affected by supplier disruptions. In particular, distributors are impacted in two ways: indirectly and directly. On the one hand, indirect transmission of the supplier’s disruption risk to distributors is assumed to be an outcome of interrupted material flows for the production and sales of whole vehicles along the supply chain. Domino effect is used to explain this phenomenon. On the other hand, direct transmission is presumed to originate from the direct business contact between the supplier and distributors in terms of automotive spare parts. Based on primary findings, this paper further investigates strategies used by manufacturers and distributors to mitigate the adverse effects of supplier disruptions through semi-structured interviews. Theoretical and practical implications, as well as limitations, are discussed.     

An empirical study of design and testing of hybrid evolutionary–neural approach for classification

We propose a hybrid evolutionary–neural approach for binary classification that incorporates a special training data over-fitting minimizing selection procedure for improving the prediction accuracy on holdout sample. Our approach integrates parallel global search capability of genetic algorithms (GAs) and local gradient-descent search of the back-propagation algorithm. Using a set of simulated and real life data sets, we illustrate that the proposed hybrid approach fares well, both in training and holdout samples, when compared to the traditional back-propagation artificial neural network (ANN) and a genetic algorithm-based artificial neural network (GA-ANN).