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- Andersson, Tobias, 1973-, et al.
(författare)
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Decision support for efficient ambulance logistics
- 2007
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Ingår i: Operational Research for Health Policy: Making Better Decisions. - Bern, Switzerland : Peter Lang AG. - 9783039110933 ; , s. 107-125
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Konferensbidrag (refereegranskat)abstract
- Ambulance logistics comprises everything that has to do with managing an efficient ambulance health care, which includes both emergency medical services and patient transportations. In this work, ambulance logistics is defined and discussed using the Swedish public service enterprise SOS Alarm as a basis. A number of ways of improving the ambulance logistic service provided by SOS Alarm are identified, and nine areas of improvement are defined. Two of the nine areas, -Visualisation of the preparedness- and -Decision support for efficient ambulance logistics- are described in more detail. In both of these, the main improvement lays in the development of decision support tools for the ambulance dispatchers. The tools that are developed are a preparedness calculator, an ambulance dispatch suggestion tool, a relocation tool and a simulation tool.
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- Andersson, Tobias, 1973-, et al.
(författare)
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Dynamic ambulance relocation for a higher preparedness
- 2004
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Ingår i: 35th Annual Meeting of the Decision Sciences Institute,2004. - Atlanta, Georia, USA : Decision Sciences Institute. ; , s. 3911-
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Konferensbidrag (refereegranskat)
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- Andersson, Tobias, 1973-, et al.
(författare)
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OPAL - Optimized ambulance logistics
- 2004
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Ingår i: TRISTIN V: 5th Triennial Symposium on Transport Analysis,2004.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Björklund, Patrik, 1970-, et al.
(författare)
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A Column Generation Method for Spatial TDMA Scheduling in Ad Hoc Networks
- 2004
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Ingår i: Ad hoc networks. - : Elsevier BV. - 1570-8705 .- 1570-8713. ; 2:Issue 4, s. 405-418
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Tidskriftsartikel (refereegranskat)abstract
- An ad hoc network can be set up by a number of units without the need of any permanent infrastructure. Two units establish a communication link if the channel quality is sufficiently high. As not all pairs of units can establish direct links, traffic between two units may have to be relayed through other units. This is known as the multi-hop functionality. In military command and control systems, ad hoc networks are also referred to as multi-hop radio networks. Spatial TDMA (STDMA) is a scheme for access control in ad hoc networks. STDMA improves TDMA by allowing simultaneous transmission of multiple units. In this paper, we study the optimization problem of STDMA scheduling, where the objective is to find minimum-length schedules. Previous work for this problem has focused on heuristics, whose performance is difficult to analyze when optimal solutions are not known. We develop novel mathematical programming formulations for this problem, and present a column generation solution method. Our numerical experiments show that the method generates a very tight bound to the optimal schedule length, and thereby enables optimal or near-optimal solutions. The column generation method can be used to provide benchmarks when evaluating STDMA scheduling algorithms. In particular, we use the bound obtained in the column generation method to evaluate a simple greedy algorithm that is suitable for distributed implementations.
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| 9. |
- Björklund, Patrik, 1970-, et al.
(författare)
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A Simulated Annealing Algorithm for Frequency Assignment in Frequency Hopping GSM Networks
- 2003
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Ingår i: International Conference on Computer, Communication and Control Technolgies CCCT 03,2003. - Orlando : IIIS. ; , s. 155-
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Konferensbidrag (refereegranskat)abstract
- We consider the frequency assignment problem in frequency hopping GSM networks, where the task is to construct and assign lists of frequencies to blocks of transceivers, such that the total interference is minimized. We present a mathematical model and describe a simulated annealing algorithm. The algorithm explores the solution space by solving an integer program in each iteration. Computational experiments for real-life and synthesized networks show that considerable interference reduction can be achieved using the algorithm.
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| 10. |
- Björklund, Patrik, 1970-, et al.
(författare)
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Resource Optimization of Spatial TDMA in Ad Hoc Radio networks : A Column Generation Approach
- 2003
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Ingår i: IEEE INFOCOM 2003,2003. - San Francisco : IEEE. ; , s. 818-
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Konferensbidrag (refereegranskat)abstract
- Wireless communications using ad hoc networks are receiving an increasing interest. The most attractive feature of ad hoc networks is the flexibility. The network is set up by a number of units in an ad hoc manner, without the need of any fixed infrastructure. Communication links are established between two units if the signal strength is sufficiently high. As not all pairs of nodes can establish direct links, the traffic between two units may have to be relayed through other units. This is known as the multihop functionality. Design of ad hoc networks is a challenging task. In this paper we study the problem of resource allocation with spatial TDMA (STDMA) as the access control scheme. Previous work for this problem has mainly focused on heuristics, whose performance is difficult to analyze when optimal solutions are not known. We develop, for both node-oriented and link-oriented allocation strategies, mathematical programming formulations for resource optimization. We further present a column generation approach, which, in our numerical experiments, constantly yields optimal or near-optimal solutions. Our results provide important benchmarks when evaluating heuristic on-line algorithms for resource optimization using STDMA.
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