On the equitable k *-laceability of hypercubes

Let G be a finite undirected bipartite graph. Let u, v be two vertices of G from different partite sets. A collection of k internal vertex disjoint paths joining u to v is referred as a k-container C _k (u,v). A k-container is a k ^*-container if it spans all vertices of G. We define G to be a k ^*-laceable graph if there is a k ^*-container joining any two vertices from different partite sets. A k ^*-container C _k ^*(u,v)={P ₁,…,P _k } is equitable if ||V(P _i )|−|V(P _j )||≤2 for all 1≤i,j≤k. A graph is equitably k ^*-laceable if there is an equitable k ^*-container joining any two vertices in different partite sets. Let Q _n be the n-dimensional hypercube. In this paper, we prove that the hypercube Q _n is equitably k ^*-laceable for all k≤n−4 and n≥5. Dedicated to Professor Frank K. Hwang on the occasion of his 65th birthday. The work of H.-M. Huang was supported in part by the National Science Council of the Republic of China under NSC94-2115-M008-013.     

The orbit problem is in the GapL hierarchy

The Orbit problem is defined as follows: Given a matrix A∈ℚ ^n×n and vectors x,y∈ℚ ⁿ , does there exist a non-negative integer i such that A ⁱ x=y. This problem was shown to be in deterministic polynomial time by Kannan and Lipton (J. ACM 33(4):808–821, 1986). In this paper we place the problem in the logspace counting hierarchy GapLH. We also show that the problem is hard for C₌L with respect to logspace many-one reductions.     

Quality management and performance: a comparison between the UK and Turkey

Purpose: The aim of this article is to detail the correlation between quality management, specifically its tools and critical success factors, and performance in terms of primary operational and secondary organisational performances.

Design/methodology/approach: Survey data from the UK and Turkey were analysed using exploratory factor analyses, structural equation modelling and regression analysis.

Findings: The results show that quality management has a significant and positive impact on both primary and secondary performances; that Turkish and UK attitudes to quality management are similar; and that quality management is widely practised in manufacturing and service industries but has more statistical emphasis in the manufacturing sector. The main challenge for making quality management practice more effective lies in an appropriate balanced use of the different sorts of the tools and critical success factors.

Originality/value: This study takes a novel approach by: (i) exploring the relationship between primary operational and secondary organisational performances, (ii) using service and manufacturing data and (iii) making a cross-country comparison between the UK (a developed economy) and Turkey (a developing economy).

Limitations: Detailed contrast provided between only two countries.     

Book reviews and books received

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Clergy under Stress: A study of homosexual and heterosexual clergy in the Church of England. By Dr Ben Fletcher Mowbray, London 1990. £6.95 (pbk). ISBN 0-264-67196-1.

Making Shiftwork Tolerable By T. H. Monk and S. Folkard Taylor &; Francis. London, 1992. vii + 94 pp. £11.50. ISBN 0-85966-822-0.

Diving and Subaquatic Medicine, By Carl Edmonds, Chiwtopher Lowry, and John Pennefather, 3rd edn Butterworth-Heinemann Ltd, Oxford. (1992). pp xii + 565. 049.50     

Book reviews

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Self development for managers—thriving on stress, By Jane Cranwell-Ward, Routledge, London, 1990. £6.95 (pbk). ISBN 0415-04465-0 [142 PP.].

Causes, coping and consequences of stress at work, Edited by Cary L. Cooper and Roy Payne, Wiley, Chichester, 2nd edn 1988, Reprinted 1990. £29.95 (hbk). ISBN 0-471-94453-X [430 PP.].     

Calendar

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The Healthy Organization-Fairness, Ethics and Effective Management By Susannewell, Routledge, London, 1996 L12.99 (pbk). ISBN 04-151-03274 [vit + 216 pp.].

Workplace Health : Employee Fitness and Exercise Edited by JOHN KERR, TOM COXand AMANDA GRIFFITHS, Taylor &; Francis, London, 1996. A36.00 (hbk), ISBN 07484-0142-3. £17.95 (pbk). ISBN 07484-0143-1. [xiv+ 187 pp.].     

Book review

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Corporate Assessment, By A. Furnham and B. Gunter, Routledge, London, 1993. £19.99 (hbk). ISBN 0-425-08118-1 [xiii + 293 pp].     

The shortest path improvement problems under Hamming distance

In this paper, we consider the shortest path improvement problems under Hamming distance (SPIH), where the weights of edges can be modified only within given intervals. Two models are considered: the general SPIH problem and the SPIH problem with a single pair of required vertices. For the first problem, we show that it is strongly NP-hard. For the second problem, we show that even if the network is a chain network, it is still NP-hard.This paper is dedicated to Dr. Yong He.     

Probabilistic graph-coloring in bipartite and split graphs

We revisit in this paper the stochastic model for minimum graph-coloring introduced in (Murat and Paschos in Discrete Appl. Math. 154:564–586, 2006), and study the underlying combinatorial optimization problem (called probabilistic coloring) in bipartite and split graphs. We show that the obvious 2-coloring of any connected bipartite graph achieves standard-approximation ratio 2, that when vertex-probabilities are constant probabilistic coloring is polynomial and, finally, we propose a polynomial algorithm achieving standard-approximation ratio 8/7. We also handle the case of split graphs. We show that probabilistic coloring is NP-hard, even under identical vertex-probabilities, that it is approximable by a polynomial time standard-approximation schema but existence of a fully a polynomial time standard-approximation schema is impossible, even for identical vertex-probabilities, unless P=NP. We finally study differential-approximation of probabilistic coloring in both bipartite and split graphs. Part of this research has been performed while the second author was with the LAMSADE on a research position funded by the CNRS.     

Distance graphs on R n with 1-norm

Suppose S is a subset of a metric space X with metric d. For each subset D⊆{d(x,y):x,y∈S,x≠y}, the distance graph G(S,D) is the graph with vertex set S and edge set E(S,D)={xy:x,y∈S,d(x,y)∈D}. The current paper studies distance graphs on the n-space R ₁ ⁿ with 1-norm. In particular, most attention is paid to the subset Z ₁ ⁿ of all lattice points of R ₁ ⁿ . The results obtained include the degrees of vertices, components, and chromatic numbers of these graphs. Dedicated to Professor Frank K. Hwang on the occasion of his 65th birthday. Supported in part by the National Science Council under grant NSC-94-2115-M-002-015. Taida Institue for Mathematical Sciences, National Taiwan University, Taipei 10617, Taiwan. National Center for Theoretical Sciences, Taipei Office.     

Trait-Based Personality Theory,Ontogenic Behavioral Continuity,and Behavior Analysis

Abstract

SHACKLETON'S WAY: LEADERSHIP LESSONS FROM THE GREAT ANTARCTIC EXPLORER. by Morrell, M. and Capparell, S. (2001). New York: Penguin, 215 pp. Reviewed by Philip N. Chase.     

Editorial board page for “Work & Stress”, Volume 6, Number 3

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This is a scanned image of the original Editorial Board page(s) for this issue.     

Editorial board page for “Work & Stress”, Volume 4, Number 4

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This is a scanned image of the original Editorial Board page(s) for this issue.     

Editorial board page for “Work & Stress”, Volume 12, Number 2

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This is a scanned image of the original Editorial Board page(s) for this issue.     

Editorial board page for “Work & Stress”, Volume 5, Number 1

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This is a scanned image of the original Editorial Board page(s) for this issue.     

Editorial board page for “Work & Stress”, Volume 11, Number 3

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This is a scanned image of the original Editorial Board page(s) for this issue.     

Editorial board page for “Work & Stress”, Volume 12, Number 1

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This is a scanned image of the original Editorial Board page(s) for this issue.     

Editorial board page for “Work & Stress”, Volume 8, Number 1

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This is a scanned image of the original Editorial Board page(s) for this issue.     

Editorial board page for “Work & Stress”, Volume 3, Number 1

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This is a scanned image of the original Editorial Board page(s) for this issue.     

Editorial board page for “Work & Stress”, Volume 3, Number 4

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This is a scanned image of the original Editorial Board page(s) for this issue.