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Article
Publication date: 15 October 2020

Vicente Jara-Vera and Carmen Sánchez-Ávila

The distribution of natural numbers in the Ulam spiral manifests a series of unexpected regularities of the elusive prime numbers. Their sequencing remains a topic of research…

Abstract

Purpose

The distribution of natural numbers in the Ulam spiral manifests a series of unexpected regularities of the elusive prime numbers. Their sequencing remains a topic of research interest, with many ramifications in different branches of Mathematics, especially in number theory and the prime factorisation problem. Accordingly, the focus of the research is on the most known and widespread asymmetric cryptographic system, that is, the RSA encryption.

Design/methodology/approach

This paper presents the presence of one, two, three or four adjacencies for the diverse primes that appear in a spiral, considering the Hardy–Littlewood twin prime conjecture and the constellations of primes.

Findings

Through equations, the calculation formulas of primes inside a spiral that have one to four primes in their adjacent places is offered, with approximate expressions that facilitate the operations, showing that the adjacencies decrease very rapidly as the spiral progresses, although without disappearing.

Originality/value

A generalisation to cases in which the distances to the prime values change in an ascending way in accordance with the step of the Ulam spiral is offered.

Details

Engineering Computations, vol. 38 no. 4
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 October 1994

David A. Edgar, David L. Litteljohn and Myrtle L. Allardyce

Short breaks are one important segment of the overall tourism market.They provide a distinct market sector with, it appears, specialcompetitive strategies. While the growth and…

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Abstract

Short breaks are one important segment of the overall tourism market. They provide a distinct market sector with, it appears, special competitive strategies. While the growth and value of this market sector is undisputed, little attention has been paid to the strategic nature of short break provision, or the potential of movement in strategic space. Using data gathered from personal interviews and applying the concept of strategic group clusters and strategic space, explores strategy and performance differences of companies operating in the UK short break market. Examines correlation between structural variables of market scope, company size; and sources of competitive advantage in relation to prime strategies adopted. Draws conclusions with regard to shifts in strategic space for performance enhancement, and potential future market developments.

Details

International Journal of Contemporary Hospitality Management, vol. 6 no. 5
Type: Research Article
ISSN: 0959-6119

Keywords

Article
Publication date: 1 April 2005

Robert A. Fairthorne

Aims to build on the work of Buckland and Hindle regarding statistical distribution as applied to the field of bibliometrics, particularly the use of empirical laws.

1588

Abstract

Purpose

Aims to build on the work of Buckland and Hindle regarding statistical distribution as applied to the field of bibliometrics, particularly the use of empirical laws.

Design/methodology/approach

Gives examples of hyperbolic distributions that have a bearing on the bibliometric application, and discusses the characteristics of hyperbolic distributions and the Bradford distribution.

Findings

Hyperbolic distributions are the inevitable result of combinatorial necessity and a tendency to short‐term rational behaviour.

Originality/value

Supports Bradford's conclusion from his law, i.e. that to know about one's speciality, one must go outside it.

Details

Journal of Documentation, vol. 61 no. 2
Type: Research Article
ISSN: 0022-0418

Keywords

Article
Publication date: 1 April 1969

ROBERT A. FAIRTHORNE

Since 1960, and especially during the past three years, many papers have appeared about particular manifestations and applications of a certain class of empirical laws to a field…

Abstract

Since 1960, and especially during the past three years, many papers have appeared about particular manifestations and applications of a certain class of empirical laws to a field that may be labelled conveniently ‘Bibliometrics’. This term, resuscitated by Alan Pritchard (see page 348), denotes, in my paraphrase, quantitative treatment of the properties of recorded discourse and behaviour appertaining to it.

Details

Journal of Documentation, vol. 25 no. 4
Type: Research Article
ISSN: 0022-0418

Article
Publication date: 1 August 1981

Lynn E. Gill and Robert P. Allerheiligen

Historically goods and services have been distributed through networks in which loosely aligned firms have bargained at arm's length, negotiated aggressively over price and other…

Abstract

Historically goods and services have been distributed through networks in which loosely aligned firms have bargained at arm's length, negotiated aggressively over price and other conditions of sale, and otherwise behaved autonomously. However, planned vertical marketing systems are rapidly displacing these conventional marketing channels as the dominant mode of distribution in the American economy. These vertical marketing systems tend to be professionally managed, pre‐planned, rationalised, and capital intensive. According to McCammon, over 60 per cent of total retail sales are through firms affiliated with vertical marketing systems.

Details

International Journal of Physical Distribution & Materials Management, vol. 11 no. 8
Type: Research Article
ISSN: 0269-8218

Article
Publication date: 5 February 2021

Mathieu Seppey, Paul-André Somé and Valéry Ridde

A performance-based financing (PBF) pilot project was implemented in 2011 in Burkina Faso. After more than five years of implementation (data collection in 2016), the project's…

Abstract

Purpose

A performance-based financing (PBF) pilot project was implemented in 2011 in Burkina Faso. After more than five years of implementation (data collection in 2016), the project's sustainability was not guaranteed. This study's objective is to assess this project's sustainability in 2016 by identifying the presence/absence of different determinants of sustainability according to the conceptual framework of Seppey et al. (2017).

Design/methodology/approach

It uses a case study approach using in-depth interviews with various actors at the local, district/regional and national levels. Participants (n = 37) included health practitioners, management team members, implementers and senior members of health directions. A thematic analysis based on the conceptual framework was conducted, as well as an inductive analysis.

Findings

Results show the project's sustainability level was weak according to an unequal presence of sustainability's determinants; some activities are being maintained but not fully routinised. Discrepancies between the project and the context's values appeared to be important barriers towards sustainability. Project's ownership by key stakeholders also seemed superficial despite the implementers' leadership towards its success. The project's objective towards greater autonomy for health centres was also directly confronting the Burkinabe's hierarchical health system.

Originality/value

This study reveals many fits and misfits between a PBF project and its context affecting its ability to sustain activities through time. It also underlines the importance of using a conceptual framework in implementing and evaluating interventions. These results could be interesting for decision-makers and implementers in further assessing PBF projects elsewhere.

Details

Journal of Health Organization and Management, vol. 35 no. 3
Type: Research Article
ISSN: 1477-7266

Keywords

Article
Publication date: 1 January 1989

MICHAEL BUKINGHAM

Planned distribution is a management tool, not an irrelevant headache. Michael Buckingham reviews a conference designed to promote its application.

Abstract

Planned distribution is a management tool, not an irrelevant headache. Michael Buckingham reviews a conference designed to promote its application.

Details

Logistics World, vol. 2 no. 1
Type: Research Article
ISSN: 0953-2137

Article
Publication date: 11 February 2019

Nataliya Chukhrova and Arne Johannssen

In acceptance sampling, the hypergeometric operating characteristic (OC) function (so called type-A OC) is used to be approximated by the binomial or Poisson OC function, which…

101

Abstract

Purpose

In acceptance sampling, the hypergeometric operating characteristic (OC) function (so called type-A OC) is used to be approximated by the binomial or Poisson OC function, which actually reduce computational effort, but do not provide suffcient approximation results. The purpose of this paper is to examine binomial- and Poisson-type approximations to the hypergeometric distribution, in order to find a simple but accurate approximation that can be successfully applied in acceptance sampling.

Design/methodology/approach

The authors present a new binomial-type approximation for the type-A OC function, and derive its properties. Further, the authors compare this approximation via an extensive numerical study with other common approximations in terms of variation distance and relative efficiency under various conditions on the parameters including limiting cases.

Findings

The introduced approximation generates best numerical results over a wide range of parameter values, and ensures arithmetic simplicity of the binomial distribution and high accuracy to meet requirements regarding acceptance sampling problems. Additionally, it can considerably reduce the computational effort in relation to the type-A OC function and therefore is strongly recommended for calculating sampling plans.

Originality/value

The newly presented approximation provides a remarkably close fit to the type-A OC function, is discrete and needs no correction for continuity, and is skewed in the same direction by roughly the same amount as the exact OC. Due to less factorials, this OC in general involves lower powers than the type-A OC function. Moreover, the binomial-type approximation is easy to fit to the conventional statistical computing packages.

Details

International Journal of Quality & Reliability Management, vol. 36 no. 4
Type: Research Article
ISSN: 0265-671X

Keywords

Case study
Publication date: 26 May 2020

Abdul Rehman Shaikh and Asad Ali Qazi

The learning outcomes are as follows: to describe the possible problems in cross hierarchical and cross-functional coordination; to illustrate the month/year-end closing…

Abstract

Learning outcomes

The learning outcomes are as follows: to describe the possible problems in cross hierarchical and cross-functional coordination; to illustrate the month/year-end closing operations related issues at logistics and warehousing end; to analyze the importance of supply chain resilience/ contingency plan; and to compare the role of the tradeoff in decision-making: ethics (policies) vs operations.

Case overview/synopsis

Mr Azhar Ali working as a regional distribution manager was waiting for the finalization of sales orders, it was the last working day of the financial year. He had to fulfill all the orders to achieve his personal and organizational goals. He was excited as he was supposed to be promoted and transferred to Head Office on a national role, after a successful annual closing. It was not too late when his excitement turned into anxiety when he received a never expected direct call from Director Sales. Around 7:00 p.m., he was informed of some new orders for an important institutional customer, which was out of his own region. The orders were placed in Ali’s region because of stocks’ availability. Ali had no time to plan this huge order and there were no dispatch trucks available at that time. Should Ali take risk of organizational goals and his promotion and cancel those orders? Should Ali generate sales invoices to record sales and dispatch the stocks on next day compromising the organizational core values and policies?

Complexity academic level

BBA.

Supplementary materials

Teaching Notes are available for educators only.

Subject code

CSS 9: Operations and logistics.

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