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Publications (10 of 12) Show all publications
Hedvall, L. & Wikner, J. (2019). Decision-Making Process for Buffer Dimensioning in Manufacturing. In: IFIP Advances in Information and Communication Technology: . Paper presented at IFIP WG 5.7 International Conference on Advances in Production Management Systems, APMS 2019, Austin, United States, 1 - 5 September 2019 (pp. 196-203). Springer, 567
Open this publication in new window or tab >>Decision-Making Process for Buffer Dimensioning in Manufacturing
2019 (English)In: IFIP Advances in Information and Communication Technology, Springer, 2019, Vol. 567, p. 196-203Conference paper, Published paper (Refereed)
Abstract [en]

Systematic and stochastic variations, both endogenous and exogenous to companies, are a constant challenge for decision makers struggling to maintain a competitive advantage for the business. In response the decision maker introduces buffers to absorb variations but this does not target the source of the problem. The first step should instead be to focus on how to reduce variations and then to handle the remnant variations. In summary the first step should be to perform variation management and then as the second step buffer management should be applied. The combination of these two subprocesses represent service performance management and within this context is buffer dimensioning a key challenge. Input data, decision maker and process logic are identified as three key aspects of buffer dimensioning which are integrated and resulting in six scenarios. These scenarios unravel different conditions for performing buffer dimensioning and facilitate an awareness of a match or mismatch between current and desired situation. 

Place, publisher, year, edition, pages
Springer, 2019
Series
IFIP Advances in Information and Communication Technology, ISSN 1868-4238, E-ISSN 1868-422X ; 567
Keywords
Buffer dimensioning, Dimensioning process, Service performance management, Competition, Industrial management, Stochastic systems, Buffer management, Competitive advantage, Decision making process, Reduce variation, Service performance, Stochastic variation, Variation management, Decision making
National Category
Business Administration
Identifiers
urn:nbn:se:hj:diva-46726 (URN)10.1007/978-3-030-29996-5_23 (DOI)000507552200023 ()2-s2.0-85072953746 (Scopus ID)9783030299958 (ISBN)
Conference
IFIP WG 5.7 International Conference on Advances in Production Management Systems, APMS 2019, Austin, United States, 1 - 5 September 2019
Available from: 2019-10-25 Created: 2019-10-25 Last updated: 2020-02-03Bibliographically approved
Wikner, J., Hedvall, L. & Mattsson, S.-A. (2019). Hierarchical adaptive control of safety buffers in manufacturing. Paper presented at 9th IFAC/IFIP/IFORS/IISE/INFORMS Conference on Manufacturing Modelling, Management and Control (IFAC MIM), August 28-30, 2019, Berlin, Germany. IFAC-PapersOnLine, 52(13), 2626-2631
Open this publication in new window or tab >>Hierarchical adaptive control of safety buffers in manufacturing
2019 (English)In: IFAC-PapersOnLine, E-ISSN 2405-8963, Vol. 52, no 13, p. 2626-2631Article in journal (Refereed) Published
Abstract [en]

Buffer management is an important part of manufacturing planning and control where the safety buffers provide robustness in relation to uncertainty in demand and supply. Hierarchical control of safety buffers highlights the significance of decisions made at different levels and for different purposes with inter-level feedback and intra-level adaptation. A period-based view of time complements the hierarchical control by identifying inter-period and intra-period aspects of managing uncertainty and thereby promoting a proactive dominated or reactive dominated way of managing uncertainty. By combining these two inter vs. intra based concepts, a hierarchical approach to adaptive safety buffer control in manufacturing planning and control is outlined.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Adaptive control, buffer dimensioning, safety inventory, safety capacity, planning and control
National Category
Production Engineering, Human Work Science and Ergonomics
Identifiers
urn:nbn:se:hj:diva-47428 (URN)10.1016/j.ifacol.2019.11.603 (DOI)000504282400444 ()2-s2.0-85078951497 (Scopus ID)POA JTH 2019 (Local ID)POA JTH 2019 (Archive number)POA JTH 2019 (OAI)
Conference
9th IFAC/IFIP/IFORS/IISE/INFORMS Conference on Manufacturing Modelling, Management and Control (IFAC MIM), August 28-30, 2019, Berlin, Germany
Available from: 2020-01-16 Created: 2020-01-16 Last updated: 2020-02-24Bibliographically approved
Hedvall, L. (2019). Reducing and absorbing variations in a manufacturing context: A capacity management perspective. (Licentiate dissertation). Jönköping: Jönköping University, School of Engineering
Open this publication in new window or tab >>Reducing and absorbing variations in a manufacturing context: A capacity management perspective
2019 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Variations can have substantially negative effects on performance and it is therefore important to investigate how the variations can be reduced or absorbed in an appropriate way for competitiveness. Manufacturing companies are daily exposed to variations and operations managers need to take capacity management decisions with this in mind to secure the delivery capability. The current body of knowledge mainly focus on techniques for root cause analysis for reducing variations, especially in the manufacturing processes, neglecting the fact that both internally and externally generated variations are more or less possible to affect. Buffers are traditionally associated with waste and unfavourable performance, while the right buffers can be of strategic importance. The purpose of this research is therefore to increase the understanding of causes for variations, actions to reduce variations and how buffers can be used to mitigate negative effects of variations related to capacity management in a manufacturing context.

Three research studies have been conducted, including four appended papers, to fulfil the purpose. These studies encompassed different combinations of traditional literature reviews, conceptual research with logical reasoning and case study research. The findings demonstrate that working on mitigating negative effects of variations is a complex challenge and not just about choosing to reduce or absorb the variations. In general, it is concluded that the variation management and buffer management include several aspects to consider with implications for the capacity management. In addition, the results indicate that the decisions in manufacturing companies tend to be based on intuition and previous experience due to a lack of decision support. Furthermore, the participating companies perceive that several of their internal routines contribute to their prevailing variations. This research contributes to an awareness of causes for variations that are possible to affect, possible actions to reduce the variations and the purposes of different buffers to absorb variations. This is sought to facilitate a systematic way of working with reducing and absorbing variations, creating support in the variation management and the buffer management from a capacity management perspective.

Abstract [sv]

Variationer kan medföra negativa effekter för en verksamhets prestation och det är därmed viktigt att utforska hur variationerna kan reduceras eller absorberas på lämpligt sätt för att verksamheten ska vara konkurrenskraftig. Tillverkande företag är dagligen exponerade för variationer och produktionschefer behöver beakta detta i kapacitetsadministrationen för att säkerställa leveransförmågan. Befintlig litteratur fokuserar främst på tekniker för att analysera grundorsaker inom tillverkningsprocesserna och ignorerar det faktum att både internt och externt genererade variationer är mer eller mindre påverkbara. Buffertar associeras traditionellt med oönskat slöseri fastän rätt buffertar kan vara av strategisk betydelse. Syftet med denna forskning är därmed att öka förståelsen för orsaker till variationer, åtgärder för att reducera variationer och hur buffertar kan tillämpas för att överkomma negativa effekter av variationer i relation till kapacitetsadministration inom en tillverkningskontext.

Tre forskningsstudier, innefattande fyra publikationer, har genomförts för att uppfylla syftet. Dessa studier består av en kombination av traditionella litteraturstudier, konceptuell forskning med logiska resonemang och fallstudier i tillverkande företag. Resultaten visar att arbetet med att hantera negativa effekter av variationer är en komplex utmaning som stäcker sig bortom valet av att reducera eller absorbera variationerna. Generellt dras slutsatsen att det är flertalet aspekter att beakta för variationsadministration och buffertadministration med implikationer för kapacitetsadministrationen. Det visade sig att besluten tenderar att vara baserat på intuition och erfarenheter i tillverkande företag, mycket till följd av en avsaknad av beslutsstöd. Vidare framgår det att de medverkande företagen upplever att flera av deras interna rutiner bidrar till upphovet av variationer. Denna forskning bidrar till en ökad medvetenhet om orsaker till variationer som är påverkbara inom företag, möjliga åtgärder för att reducera variationerna och syftet med olika buffertar för att absorbera variationer. Detta är avsett att underlätta ett systematiskt arbetssätt för att reducera och absorbera variationer, samt utgöra ett stöd för variationsadministration och buffertadministration från ett kapacitetsadministrationsperspektiv.

Place, publisher, year, edition, pages
Jönköping: Jönköping University, School of Engineering, 2019. p. 73
Series
JTH Dissertation Series ; 042
Keywords
capacity management, variation management, buffer management, manufacturing companies, manufacturing planning and control, kapacitetsadministration, variationsadministration, buffertadministration, tillverkande företag, material- och produktionsstyrning
National Category
Business Administration Production Engineering, Human Work Science and Ergonomics
Identifiers
urn:nbn:se:hj:diva-43666 (URN)978-91-87289-45-3 (ISBN)
Presentation
2019-05-27, E4404, Jönköping University, School of Engineering, Jönköping, 10:00 (English)
Opponent
Supervisors
Projects
KOPability
Available from: 2019-05-14 Created: 2019-05-14 Last updated: 2019-05-14Bibliographically approved
Wikner, J. & Hedvall, L. (2018). A Flow Based Foundation for Capacity Dimensioning. In: Moon I., Lee G., Park J., Kiritsis D., von Cieminski G. (Ed.), Moon I., Lee G., Park J., Kiritsis D., von Cieminski G. (Ed.), Advances in Production Management Systems. Production Management for Data-Driven, Intelligent, Collaborative, and Sustainable Manufacturing. APMS 2018: . Paper presented at IFIP WG 5.7 International Conference, APMS 2018, Seoul, Korea, August 26-30, 2018 (pp. 384-391). Cham: Springer
Open this publication in new window or tab >>A Flow Based Foundation for Capacity Dimensioning
2018 (English)In: Advances in Production Management Systems. Production Management for Data-Driven, Intelligent, Collaborative, and Sustainable Manufacturing. APMS 2018 / [ed] Moon I., Lee G., Park J., Kiritsis D., von Cieminski G., Cham: Springer, 2018, p. 384-391Conference paper, Published paper (Refereed)
Abstract [en]

To proactively decide on the volume of capacity available in a period of time is referred to as capacity dimensioning. The actual dimensioning of capacity concerns both the regular capacity, to cater for systematic variations, and safety capacity, to handle the stochastic variations. Despite the critical impact of these two types of variations, the support in the literature is limited in terms of formal methods for resource management based on dimensioning of capacity in general, and of safety capacity in particular. Capacity is one aspect of resources’ capabilities and as a point of departure for developing such methods, the two overarching challenges of form-place-time matching and capacity balancing are defined. These challenges are exploited to provide a holistic approach to the combination of capacity and the generic form, place and time transformations performed to create customer value. This approach requires alignment between these types of transformation to enable a homogenous perspective on different types of resources such as machines and stock shelves. Such transformations are performed over time and a discrete-time period-based approach requires that the intra-period transfers and inter-period variations are integrated. Finally, the preconditions for proactive and reactive control related to capacity required are outlined. A foundation for capacity dimensioning is then established based on capacity balancing, period transfers and flow control.

Place, publisher, year, edition, pages
Cham: Springer, 2018
Series
IFIP Advances in Information and Communication Technology, ISSN 1868-4238, E-ISSN 1868-422X ; 535
Keywords
Capacity dimensioning, Safety capacity, Inventory control
National Category
Business Administration
Identifiers
urn:nbn:se:hj:diva-41356 (URN)10.1007/978-3-319-99704-9_47 (DOI)2-s2.0-85053258183 (Scopus ID)978-3-319-99703-2 (ISBN)978-3-319-99704-9 (ISBN)
Conference
IFIP WG 5.7 International Conference, APMS 2018, Seoul, Korea, August 26-30, 2018
Available from: 2018-09-05 Created: 2018-09-05 Last updated: 2019-02-13Bibliographically approved
Hedvall, L. (2018). Buffers in capacity management: A multiple case study. In: : . Paper presented at 25th International Annual EurOMA Conference, June 24-26th, 2018 Budapest, Hungary.
Open this publication in new window or tab >>Buffers in capacity management: A multiple case study
2018 (English)Conference paper, Published paper (Refereed)
Abstract [en]

A competitive delivery capability is dependent on a balance between supply and demand, a challenge that increase due to variations. This inevitably leads to a need for proper management of buffers. The purpose of this research is to investigate buffers utilized in practice in relation to a framework of buffers for capacity management. Twelve different kinds of buffers from the conceptual framework are identified in the multiple case study. The experiences from eleven respondents highlights the purposes and procedures of buffer capacity management (BCM).

Keywords
Buffers, Capacity Management, Case Study
National Category
Business Administration
Identifiers
urn:nbn:se:hj:diva-41053 (URN)
Conference
25th International Annual EurOMA Conference, June 24-26th, 2018 Budapest, Hungary
Available from: 2018-07-24 Created: 2018-07-24 Last updated: 2019-05-14Bibliographically approved
Hedvall, L. & Mattsson, S.-A. (2018). Orsaker till variationer och åtgärder för att minska behovet av buffertar. In: Proceedings of the Plan Research Conference, Jönköping, 23-24 oktober, 2018.: . Paper presented at Plans forsknings- och tillämpningskonferens, Jönköping, Sverige, 23-24 oktober 2018 (pp. 95-110).
Open this publication in new window or tab >>Orsaker till variationer och åtgärder för att minska behovet av buffertar
2018 (Swedish)In: Proceedings of the Plan Research Conference, Jönköping, 23-24 oktober, 2018., 2018, p. 95-110Conference paper, Published paper (Refereed)
Abstract [sv]

Variationer i efterfrågan, i internt genererade kapacitetsbehov, i tillgång på kapacitet och i leveranstider från leverantörer medför utmaningar för företag att uppnå kostnadseffektiva materialflöden och en konkurrenskraftig leveransförmåga. För att hantera sådana variationer finns det två principiellt olika angreppssätt. Det ena innebär att man använder sig av olika buffertar i form av extra material, extra kapacitet och extra tid för att absorbera variationerna och utgår från att förekomst av variationer accepteras. Buffertar förorsakar emellertid kostnader och kapitalbindning som måste vägas mot de fördelar som kan uppnås. Det andra angreppssättet innebär att man först försöker reducera variationerna genom att angripa orsakerna till att de förekommer med olika typer av åtgärder och genom att reducera dem kunna använda sig av mindre buffertar. Syftet med den här studien är att med utgångspunkt från detta angreppssätt utveckla ett ramverk av orsaker till att variationer förekommer och för varje orsak redovisa olika möjliga åtgärder för att begränsa dem. Avsikten är att skapa en bättre förståelse för vad det är som skapar variationer som är påverkbara i företag och ett hjälpmedel för att i praktiken identifiera möjliga åtgärder för att på ett systematiskt sätt kunna genomföra variationsreducerande aktiviteter. Syftet är också att med hjälp av ramverket studera i vilken utsträckning ett antal företag tillämpar de olika ingående åtgärderna.

Underlag till utvecklingen av olika orsaker till variationer och åtgärder för att reducera dem i ramverket har hämtats från litteraturen inom de områden som berörs. I de fall litteraturstödet varit otillräckligt eller helt saknats har i stället underlag baserats på egna erfarenheter från tillverkningsindustrin och konceptuella logiska resonemang. Studien har resulterat i ett ramverk uppdelat på fyra olika typer av variationer och bestående av sammanlagt 22 olika variationsorsaker och 61 olika slag av åtgärder. Via fallstudien har studien också bidragit med en bild av i vilken utsträckning de olika möjliga åtgärderna används i företag i praktiken för att reducera förekomst av variationer.

National Category
Business Administration
Identifiers
urn:nbn:se:hj:diva-42061 (URN)
Conference
Plans forsknings- och tillämpningskonferens, Jönköping, Sverige, 23-24 oktober 2018
Available from: 2018-11-19 Created: 2018-11-19 Last updated: 2019-02-14
Hedvall, L., Sollander, K., Wikner, J. & Hilletofth, P. (2017). Dimensionering av kapacitet i 14 företag. Bättre Produktivitet (6), 16-21
Open this publication in new window or tab >>Dimensionering av kapacitet i 14 företag
2017 (Swedish)In: Bättre Produktivitet, ISSN 1402-1145, no 6, p. 16-21Article in journal (Other (popular science, discussion, etc.)) Published
Place, publisher, year, edition, pages
Bättre Produktivitet i Viksjö, 2017
National Category
Business Administration Production Engineering, Human Work Science and Ergonomics
Identifiers
urn:nbn:se:hj:diva-39036 (URN)
Available from: 2018-03-21 Created: 2018-03-21 Last updated: 2018-09-20Bibliographically approved
Hedvall, L., Wikner, J. & Hilletofth, P. (2017). Introducing buffer management in a manufacturing planning and control framework. In: Lödding, Hermann; Riedel, Ralph; Thoben, K.-D.; Von Cieminski, Gregor; Kiritsis, Dimitris (Ed.), Advances in Production Management Systems. The Path to Intelligent, Collaborative and Sustainable Manufacturing: IFIP WG 5.7 International Conference, APMS 2017, Hamburg, Germany, September 3-7, 2017, Proceedings, Part II. Paper presented at IFIP WG 5.7 International Conference on Advances in Production Management Systems, APMS 2017, Hamburg, Germany, 3 - 7 September 2017 (pp. 366-373). Springer-Verlag New York, 514
Open this publication in new window or tab >>Introducing buffer management in a manufacturing planning and control framework
2017 (English)In: Advances in Production Management Systems. The Path to Intelligent, Collaborative and Sustainable Manufacturing: IFIP WG 5.7 International Conference, APMS 2017, Hamburg, Germany, September 3-7, 2017, Proceedings, Part II / [ed] Lödding, Hermann; Riedel, Ralph; Thoben, K.-D.; Von Cieminski, Gregor; Kiritsis, Dimitris, Springer-Verlag New York, 2017, Vol. 514, p. 366-373Conference paper, Published paper (Refereed)
Abstract [en]

Buffer management is not of a great concern when there is a perfect match between demand and supply. Demand represents the requirement for resources, and supply represents the collective capability of the resources to fulfill the requirements. A perfect match would then represent that supply can fulfill demand without any buffers involved, such as materials prepared in advance or capacity not being fully loaded. Such a perfect match is usually not possible to achieve since demand is frequently difficult to predict and the agility of the supply is limited. As a consequence, supply cannot perfectly match demand which may result in insufficient delivery performance. Different types of buffers may be employed to improve performance but they should only be used when the contribution of a buffer is greater than the cost of it. Hence, management of buffers is an important part of manufacturing planning and control (MPC) in order to mitigate such imbalances in pursuit of a competitive supply. The purpose here is therefore to define a framework for MPC that reflects the significance of buffers. To actually establish competitive supply is a complex challenge and four management perspectives are identified to support the balancing of supply with demand. Buffer management is here defined based on the intersection of these four management perspectives related to the transformation flow: the resources employed in the flow, the risk involved in the flow, the decision making related to the flow, and finally the planning and control to balance the flow.

Place, publisher, year, edition, pages
Springer-Verlag New York, 2017
Series
IFIP advances in information and communication technology, ISSN 1868-4238 ; 514
Keywords
Balance management, Hierarchical management, Manufacturing planning and control, Resource management, Risk management, Competition, Manufacture, Buffer management, Delivery performance, Demand and supply, Improve performance, Planning and control, Decision making
National Category
Business Administration
Identifiers
urn:nbn:se:hj:diva-38345 (URN)10.1007/978-3-319-66926-7_42 (DOI)2-s2.0-85029433273 (Scopus ID)9783319669250 (ISBN)9783319669267 (ISBN)
Conference
IFIP WG 5.7 International Conference on Advances in Production Management Systems, APMS 2017, Hamburg, Germany, 3 - 7 September 2017
Available from: 2018-01-04 Created: 2018-01-04 Last updated: 2019-05-14Bibliographically approved
Hedvall, L., Hilletofth, P. & Wikner, J. (2017). Strategies for capacity dimensioning in manufacturing companies. In: Proceedings of the 24th International Annual EurOMA Conference: . Paper presented at The 24th EurOMA conference, 1st-5th July 2017, Edinburgh. International Annual EurOMA Conference
Open this publication in new window or tab >>Strategies for capacity dimensioning in manufacturing companies
2017 (English)In: Proceedings of the 24th International Annual EurOMA Conference, International Annual EurOMA Conference, 2017Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
International Annual EurOMA Conference, 2017
National Category
Business Administration
Identifiers
urn:nbn:se:hj:diva-36796 (URN)
Conference
The 24th EurOMA conference, 1st-5th July 2017, Edinburgh
Available from: 2017-08-07 Created: 2017-08-07 Last updated: 2018-09-12Bibliographically approved
Hedvall, L., Sollander, K., Wikner, J. & Hilletofth, P. (2016). Kapacitetsdimensionering: 14 företags investeringsstrategier och planeringsstrategier. In: Proceedings of the Plan Research Conference, Växjö, 19-20 oktober, 2016.: . Paper presented at Forsknings- och tillämpningskonferensen. Plan
Open this publication in new window or tab >>Kapacitetsdimensionering: 14 företags investeringsstrategier och planeringsstrategier
2016 (Swedish)In: Proceedings of the Plan Research Conference, Växjö, 19-20 oktober, 2016., Plan , 2016Conference paper, Published paper (Refereed)
Abstract [sv]

Metodstödet för kapacitetsdimensionering är i dagsläget svagt, trots att det är en viktig utmaning i de flesta typer av verksamheter. Hur en kapacitetsnivå ska fastställas kommer in i flera sammanhang såsom tillverka-/köpabeslut, maskin-investering, planering och styrning samt bemanning. Denna studie är utformad för att skapa en bättre förståelse för hur industriella verksamheter arbetar med kapacitetsdimensionering i dagsläget, samt vilka faktorer och utmaningar som påverkar och är centrala i beslutsprocessen. Det har visat sig att kapacitetsdimensioneringen har interna såväl som externa påverkansfaktorer och utmaningar. I denna studie identifieras budget, investeringskostnader, konkurrensförmåga, ledningsbeslut samt grad av komplexitet och integration i försörjningskedjan som centrala påverkansfaktorer. Vidare identifieras prognoser, kommunikation, suboptimering samt bristande systemsupport i beslutsfattandet som utmaningar i beslutsprocessen.

Place, publisher, year, edition, pages
Plan, 2016
National Category
Business Administration Production Engineering, Human Work Science and Ergonomics
Identifiers
urn:nbn:se:hj:diva-32180 (URN)
Conference
Forsknings- och tillämpningskonferensen
Available from: 2016-11-01 Created: 2016-11-01 Last updated: 2017-08-07Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-4241-4407

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