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Hultqvist, Daniel
Publications (3 of 3) Show all publications
Hultqvist, D. & Olsson, L. (2006). Optimization of the raw material procurement at pulp or paper mills: The influence of weather-related risks. International Journal of Systems Science, 37(4), 253-269
Open this publication in new window or tab >>Optimization of the raw material procurement at pulp or paper mills: The influence of weather-related risks
2006 (English)In: International Journal of Systems Science, ISSN 0020-7721, Vol. 37, no 4, p. 253-269Article in journal (Refereed) Published
Abstract [en]

There are usually many sources for the supply of raw material to a pulp or paper mill in Sweden. Optimization of this supply is therefore a challenging task, and can only be managed properly if all aspects of risk are considered. In our study, these risks are related to when the weather reduces the load-bearing capacity of the ground or the roads. A stochastic and a deterministic model have been formulated, and they have been solved with mixed-integer quadratic programming and tested with data from a Swedish forest company. The results of this study show that the option value is greater than zero and that both the optimal policy and the option value change whenever the storage cost is altered. This shows that the optimal planning policy obtained from the stochastic model differs from the solution of the deterministic model.

Keywords
Forest logistics, stochastic programming
National Category
Business Administration Mathematics
Identifiers
urn:nbn:se:miun:diva-971 (URN)10.1080/00207720600568194 (DOI)000237243100005 ()2-s2.0-33645110308 (Scopus ID)4357 (Local ID)4357 (Archive number)4357 (OAI)
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2016-09-28Bibliographically approved
Hultqvist, D. & Olsson, L. (2005). A demand-based scenario optimization model for supply of raw material to the forest industry. USDA Forest Service - General Technical Report PNW (656), 331-340
Open this publication in new window or tab >>A demand-based scenario optimization model for supply of raw material to the forest industry
2005 (English)In: USDA Forest Service - General Technical Report PNW, ISSN 0887-4840, no 656, p. 331-340Article in journal (Refereed) Published
Abstract [en]

There are usually many sources for the supply of raw material to a pulp or paper mill in Sweden. The decision-maker can procure raw material from the company's own forest(s), buy in from the owners of small forests, swap with other forest operators or purchase on the international market. Wood chips for these mills are brought from sawmills and have their own transportation system, but are included in the model presented here. Optimizing the supply of raw material at a tactical planning level is a challenging task, and can only be managed properly if elements of uncertainty are considered. The solution would otherwise give few options when disturbances occur, for example when weather conditions change. The deterministic equivalent of the scenario model is formulated and solved as a convex mixed integer quadratic model. In this paper, we have focused on model building since this is a challenging task in itself. The model is tested on one small sample problem and one full-scale problem. We show how to simulate and evaluate different strategies in the flow of raw materials, from harvesting operations to delivery at the mills. In our study, the full-scale problem has been solved within reasonable time using commercially available software, and the solution indicates that the hedging effect in the stochastic solution adds flexibility. Future work will involve the development of stochastic programming algorithms to solve large-scale instances of the problem using parallel computing.

Keywords
Flexibility, Forest logistics, Load-bearing capacity, Mixed-integer quadratic programming, Stochastic programming
National Category
Business Administration Mathematics
Identifiers
urn:nbn:se:miun:diva-5701 (URN)2-s2.0-31544444988 (Scopus ID)2300 (Local ID)2300 (Archive number)2300 (OAI)
Available from: 2008-09-30 Created: 2008-09-30 Last updated: 2016-09-27Bibliographically approved
Hultqvist, D. & Olsson, L. (2004). Demand based tactical planning of the roundwood supply chain with respect to stochastic disturbances. Sundsvall: FSCN, Mitthögskolan
Open this publication in new window or tab >>Demand based tactical planning of the roundwood supply chain with respect to stochastic disturbances
2004 (English)Report (Other academic)
Place, publisher, year, edition, pages
Sundsvall: FSCN, Mitthögskolan, 2004. p. 58
Series
Rapportserie FSCN, ISSN 1650-5387 ; 2003:19
Series
FSCN-rapport ; R-03-44
Keywords
Forest logistics
National Category
Business Administration Mathematics
Identifiers
urn:nbn:se:miun:diva-5702 (URN)2301 (Local ID)2301 (Archive number)2301 (OAI)
Available from: 2009-07-09 Created: 2009-07-09 Last updated: 2011-04-06Bibliographically approved
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