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Article
Publication date: 1 March 1999

Juha‐Matti Lehtonen, Jan Holmström and Jonas Slotte

Studies the problem of producing a product range with high customer service in the implosive industries. In the implosive industries a wide range of end products are…

Abstract

Studies the problem of producing a product range with high customer service in the implosive industries. In the implosive industries a wide range of end products are manufactured from a limited number of standard materials. The problem of producing a product range with high customer service is studied within the framework of product range, capacity and customer acceptable lead time. In the existing just‐in‐time literature, strong emphasis is put on set‐up and through‐put time reduction for achieving high product availability with low cost. However, the decision regarding the product range and its implications on production control is not adequately considered. It is proposed that the relevant time scope to consider demand and capacity is the product range cycle. Three cases from the food and paper industry are studied. The cases indicate constraints for achieving quick response capability.

Details

Supply Chain Management: An International Journal, vol. 4 no. 1
Type: Research Article
ISSN: 1359-8546

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Article
Publication date: 1 March 1998

Juha‐Matti Lehtonen and Jan Holmström

There is a large body of knowledge on logistics and production control, including just‐in‐time (JIT) logistics. However, the applications specific to paper industry…

Abstract

There is a large body of knowledge on logistics and production control, including just‐in‐time (JIT) logistics. However, the applications specific to paper industry logistics are scarce and somewhat conflicting. Examines the potential contribution of alternative logistics systems in the paper industry and the scope for efficiency gains through the application of JIT logistics systems. Multiple case studies are used, with simulation for alternative business scenarios. The results indicate considerable scope for improvements in paper industry logistics, with many of the benefits deriving from JIT applications.

Details

Supply Chain Management: An International Journal, vol. 3 no. 1
Type: Research Article
ISSN: 1359-8546

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Article
Publication date: 1 December 1997

Juha‐Matti Lehtonen and Ulla Seppala

Presents a methodology called controllability analysis in logistics. Controllability focuses on two first steps of the simulation project: problem definition; and data…

Abstract

Presents a methodology called controllability analysis in logistics. Controllability focuses on two first steps of the simulation project: problem definition; and data gathering and analysis. The aim of the analysis is to reveal the potential improvement areas, and define and analyse the data so that they are ready for the simulation process. Clarifies with a case study the methodology and its use as a part of a logistics simulation project.

Details

Integrated Manufacturing Systems, vol. 8 no. 6
Type: Research Article
ISSN: 0957-6061

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Article
Publication date: 1 February 2013

Juha‐Matti Lehtonen, Paulus Torkki, Antti Peltokorpi and Teemu Moilanen

Previous studies approach surgery scheduling mainly from the mathematical modeling perspective which is often hard to apply in a practical environment. The aim of this…

Abstract

Purpose

Previous studies approach surgery scheduling mainly from the mathematical modeling perspective which is often hard to apply in a practical environment. The aim of this study is to develop a practical scheduling system that considers the advantages of both surgery categorization and newsvendor model to surgery scheduling.

Design/methodology/approach

The research was carried out in a Finnish orthopaedic specialist centre that performs only joint replacement surgery. Four surgery categorization scenarios were defined and their productivity analyzed by simulation and newsvendor model.

Findings

Detailed analyses of surgery durations and the use of more accurate case categories and their combinations in scheduling improved OR productivity 11.3 percent when compared to the base case. Planning to have one OR team to work longer led to remarkable decrease in scheduling inefficiency.

Practical implications

In surgical services, productivity and cost‐efficiency can be improved by utilizing historical data in case scheduling and by increasing flexibility in personnel management.

Originality/value

The study increases the understanding of practical scheduling methods used to improve efficiency in surgical services.

Details

International Journal of Health Care Quality Assurance, vol. 26 no. 2
Type: Research Article
ISSN: 0952-6862

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Article
Publication date: 1 February 2005

Juha‐Matti Lehtonen, Johanna Småros and Jan Holmström

Aims to examine the value of manufacturer access to downstream demand information in managing product introductions and to Identify factors affecting this value.

Abstract

Purpose

Aims to examine the value of manufacturer access to downstream demand information in managing product introductions and to Identify factors affecting this value.

Design/methodology/approach

Simulation based on actual data on 19 product introductions is used for comparing different types of demand information and their usefulness to a manufacturer. Two metrics are introduced. Bias indicates if there is a consistent difference between demand information from two sources. Delay in demand synchronization measures how long it takes for demand information from two sources to start conveying demand similarly in a transient situation.

Findings

Finds that, in the supply chain examined, demand variability is mainly induced by distributors, whereas bias and delay in demand synchronization are mainly induced by retail outlets, especially for products with large wholesale packages compared with their sales.

Research limitations/implications

The simulation model is simple and does not enable realistic examination of how a manufacturer could best use downstream demand data in managing its operations. Further research including such mechanisms as forecasts and stock‐outs is needed.

Practical implications

Provides a means for manufacturers to assess when they should invest in gaining access to downstream demand information and to estimate when their traditional information sources start to accurately convey end‐customer demand for new products.

Originality/value

Although it has been suggested that the value of access to downstream demand information could be greatest in situations with transient or irregular demand, such as product introductions, this claim has not yet been thoroughly examined. This study is a first attempt at filling this gap in the theory.

Details

International Journal of Physical Distribution & Logistics Management, vol. 35 no. 2
Type: Research Article
ISSN: 0960-0035

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Article
Publication date: 1 March 2005

Patrik Appelqvist and Juha‐Matti Lehtonen

Scheduling problems in steel plants tend to be difficult and require complex algorithms due to many constraints. An approach is presented where only the main constraints…

Abstract

Purpose

Scheduling problems in steel plants tend to be difficult and require complex algorithms due to many constraints. An approach is presented where only the main constraints are included in the scheduling algorithm. The schedule is validated using a discrete‐event simulation model that includes additional detail.

Design/methodology/approach

The combined approach is utilised for production scheduling in a steel mill in Finland. Operational performance of the steel mill is measured before and after software installation. The paper presents the scheduling environment, the software application and the resulting increase of production.

Findings

Case experiences indicate that combining optimisation techniques with simulation is beneficial. The optimisation can be kept simpler as validation with a simulation model increases the credibility and accuracy of the resulting schedule. During software development and testing, the simulation model offered a testing environment for the optimisation algorithm.

Practical implications

The case implementation was a success that increased production without making trade‐offs with other production goals. Company management estimate the productivity increase directly caused by the project to be worth €2,500,000 annually.

Originality/value

The paper presents a successful application of simulation for schedule validation in a complex and demanding environment.

Details

Journal of Manufacturing Technology Management, vol. 16 no. 2
Type: Research Article
ISSN: 1741-038X

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Article
Publication date: 13 February 2007

Juha‐Matti Lehtonen, Jaakko Kujala, Juhani Kouri and Mikko Hippeläinen

The high variability in cardiac surgery length – is one of the main challenges for staff managing productivity. This study aims to evaluate the impact of six interventions…

Abstract

Purpose

The high variability in cardiac surgery length – is one of the main challenges for staff managing productivity. This study aims to evaluate the impact of six interventions on open‐heart surgery operating theatre productivity.

Design/methodology/approach

A discrete operating theatre event simulation model with empirical operation time input data from 2,603 patients is used to evaluate the effect that these process interventions have on the surgery output and overtime work. A linear regression model was used to get operation time forecasts for surgery scheduling while it also could be used to explain operation time.

Findings

A forecasting model based on the linear regression of variables available before the surgery explains 46 per cent operating time variance. The main factors influencing operation length were type of operation, redoing the operation and the head surgeon. Reduction of changeover time between surgeries by inducing anaesthesia outside an operating theatre and by reducing slack time at the end of day after a second surgery have the strongest effects on surgery output and productivity. A more accurate operation time forecast did not have any effect on output, although improved operation time forecast did decrease overtime work.

Research limitations/implications

A reduction in the operation time itself is not studied in this article. However, the forecasting model can also be applied to discover which factors are most significant in explaining variation in the length of open‐heart surgery.

Practical implications

The challenge in scheduling two open‐heart surgeries in one day can be partly resolved by increasing the length of the day, decreasing the time between two surgeries or by improving patient scheduling procedures so that two short surgeries can be paired.

Originality/value

A linear regression model is created in the paper to increase the accuracy of operation time forecasting and to identify factors that have the most influence on operation time. A simulation model is used to analyse the impact of improved surgical length forecasting and five selected process interventions on productivity in cardiac surgery.

Details

International Journal of Health Care Quality Assurance, vol. 20 no. 1
Type: Research Article
ISSN: 0952-6862

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Article
Publication date: 1 May 2003

Johanna Småros, Juha‐Matti Lehtonen, Patrik Appelqvist and Jan Holmström

Information sharing practices such as vendor‐managed inventory (VMI) give manufacturers access to more accurate demand information, e.g. customer sales data, than before…

Abstract

Information sharing practices such as vendor‐managed inventory (VMI) give manufacturers access to more accurate demand information, e.g. customer sales data, than before. The value of this type of information sharing has been established in many studies. However, most of the research has focused on the ideal situation of the manufacturer having access to information from all downstream parties. In practice, this is rarely the case. In this paper, discrete‐event simulation is used to examine how a manufacturer can combine traditional order data available from non‐VMI customers with sales data available from VMI customers in its production and inventory control and what impact this has on the manufacturer's operational efficiency. The simulation model is based on a real‐life VMI implementation and uses actual demand and product data. The key finding is that even for products with stable demand a partial improvement of demand visibility can improve production and inventory control efficiency, but that the value of visibility greatly depends on the target products’ replenishment frequencies and the production planning cycle employed by the manufacturer.

Details

International Journal of Physical Distribution & Logistics Management, vol. 33 no. 4
Type: Research Article
ISSN: 0960-0035

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Article
Publication date: 1 October 2004

Patrik Appelqvist, Juha‐Matti Lehtonen and Jukka Kokkonen

This paper presents a framework for supply chain decision‐making. The framework is used to gain insights into applications of modelling. Current modelling practice is…

Abstract

This paper presents a framework for supply chain decision‐making. The framework is used to gain insights into applications of modelling. Current modelling practice is reviewed through a literature survey. The principal finding is a lack of published research in the area of modelling supply chain effects in the product development phase. However, it is in the product development phase where the majority of product life‐cycle costs are determined. As a guideline for further case research, we propose an approach for integration in product life cycle modelling systems. For practitioners, we point out some major requirements for implementation. Finally, we demonstrate an early application of some of the ideas.

Details

Journal of Manufacturing Technology Management, vol. 15 no. 7
Type: Research Article
ISSN: 1741-038X

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Article
Publication date: 4 August 2014

Arto Pekka Juhani Huuskonen

The purpose of this study is to examine supply network designs that large service organisations use in the residential-FM sector to respond to the organising requirements…

Abstract

Purpose

The purpose of this study is to examine supply network designs that large service organisations use in the residential-FM sector to respond to the organising requirements of their operating environments.

Design/methodology/approach

The study is theoretically grounded in the well-established literature on the organisational design and structural contingency theory. Utilising a framework of generic organising problems proposed by Miles and Snow (1978) and a multiple-case study design, the study elaborates how large service organisations organise and manage their supply networks in the Finnish residential-FM sector.

Findings

The study identifies four supply network designs that organisations use for responding to the organising problems inherent in the property and resident services domains in the residential-FM sector. These include regional production organisation, horizontal decentralisation, environment stabilisation and demand – supply pooling, reflecting the type of the service-market domain and the organisation’s service strategy.

Originality/value

The study contributes to the facilities management literature by expanding the field of inquiry from the commercial real estate sector into the emerging field of professional residential facility services. In particular, the study adds to the discussion on supply strategies and design, offering a service provider perspective to the organisation of service supply in housing.

Details

Facilities, vol. 32 no. 11/12
Type: Research Article
ISSN: 0263-2772

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