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Abstract In this paper we present a new scheduling problem and describe a shortest path based heuristic as well as a dynamic programming based exact optimization algorithm to solve it. The Selective Multi-Category Parallel-Servicing... more
Abstract In this paper we present a new scheduling problem and describe a shortest path based heuristic as well as a dynamic programming based exact optimization algorithm to solve it. The Selective Multi-Category Parallel-Servicing Problem (SMCPSP) arises when a set of jobs has to be scheduled on a server (machine) with limited capacity. Each job requests service in a prespecified time window and belongs to a certain category. Jobs may be serviced partially, incurring a penalty; however, only jobs of the same category can be ...
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Efficiently coordinating the often large number of interdependent, timetabled train move- ments on a railway junction, while satisfying a number of operational requirements, is one of the most important problems faced by a railway... more
Efficiently coordinating the often large number of interdependent, timetabled train move- ments on a railway junction, while satisfying a number of operational requirements, is one of the most important problems faced by a railway company. The most critical variant of the problem arises on a daily basis at major railway junctions where disruptions to rail traf- fic make the planned
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The Dedicated Aircraft Recovery Problem (DARP) involves decisions concerning aircraft to flight assignments in situations where unforeseen events have disrupted the existing flight schedule, eg bad weather causing flight delays. The... more
The Dedicated Aircraft Recovery Problem (DARP) involves decisions concerning aircraft to flight assignments in situations where unforeseen events have disrupted the existing flight schedule, eg bad weather causing flight delays. The dedicated aircraft recovery problem ...
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... Aircraft Landing Problem Min Wen Supervisors: Jens Clausen and Jesper Larsen ... Acknowledgements I would like to express my sincere acknowledgement to my supervisors JensClausen and Jesper Larsen for their suggestions, support and... more
... Aircraft Landing Problem Min Wen Supervisors: Jens Clausen and Jesper Larsen ... Acknowledgements I would like to express my sincere acknowledgement to my supervisors JensClausen and Jesper Larsen for their suggestions, support and en-couragement during this thesis. ...
The auction approach for the shortest path problem (SPP) as introduced by Bertsekas is tested experimentally. Parallel algorithms using the auction approach are developed and tested. Both the sequential and parallel auction algorithms... more
The auction approach for the shortest path problem (SPP) as introduced by Bertsekas is tested experimentally. Parallel algorithms using the auction approach are developed and tested. Both the sequential and parallel auction algorithms perform significantly worse than a ...
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Whereas Wolsey does an excellent job of describing the intricacies and challenges of general integer program and the techniques necessary to master the field, he basically ignores the field on network optimization. We do not claim to... more
Whereas Wolsey does an excellent job of describing the intricacies and challenges of general integer program and the techniques necessary to master the field, he basically ignores the field on network optimization. We do not claim to master this in total but we address the most important problems in network optimization in relation to Wolseys text. ... We have included two supplementary readings in form of a chapter on duality and branch and bound. Finally an appendix contains a small introduction to the interactive part of CPLEX. ... 2 Teaching Duality in Linear ...
Abstract The performance of the auction algorithms for the shortest paths has been investigated in four papers with di ering conclusions. In the following I report a series of experiments with the code from the two most recent papers. The... more
Abstract The performance of the auction algorithms for the shortest paths has been investigated in four papers with di ering conclusions. In the following I report a series of experiments with the code from the two most recent papers. The experiments clearly show that the auction algorithm is inferior to state-of-theart shortest paths algorithms Keywords: shortest path problem, auction algorithm, performance results.
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Division of labour in ant societies is a kind of role model for distributed problem solving. They are so because ants are simple, non-cognitive, distributed and autonomous and yet they solve an optimisation problem that is very complex... more
Division of labour in ant societies is a kind of role model for distributed problem solving. They are so because ants are simple, non-cognitive, distributed and autonomous and yet they solve an optimisation problem that is very complex and dynamic. This is very desirable in computer science, but as of yet not much research has gone into explaining the underlying
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Dietary gluten influences the development of type 1 diabetes in nonobese diabetic (NOD) mice and biobreeding rats, and has been shown to influence a wide range of immunological factors in the pancreas and gut. In the present study, the... more
Dietary gluten influences the development of type 1 diabetes in nonobese diabetic (NOD) mice and biobreeding rats, and has been shown to influence a wide range of immunological factors in the pancreas and gut. In the present study, the effects of gluten on NK cells were studied in vitro and in vivo. We demonstrated that gliadin increased direct cytotoxicity and IFN-γ secretion from murine splenocytes and NK cells toward the pancreatic beta-cell line MIN6 cells. Additionally, stimulation of MIN6 cells led to a significantly increased proportion of degranulating C57BL/6 CD107a(+) NK cells. Stimulation of C57BL/6 pancreatic islets with gliadin significantly increased secretion of IL-6 more than ninefold. In vivo, the gluten-containing diet led to a higher expression of NKG2D and CD71 on NKp46(+) cells in all lymphoid organs in BALB/c and NOD mice compared with the gluten-free diet. Collectively, our data suggest that dietary gluten increases murine NK-cell activity against pancreatic beta cells. This mechanism may contribute to development of type 1 diabetes and explain the higher disease incidence associated with gluten intake in NOD mice.
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ABSTRACT A tramp ship operator often has contracted cargoes that must be carried and seeks to maximize profit by carrying optional cargoes. Hence, tramp ships operate much like taxies following available cargo and not according to fixed... more
ABSTRACT A tramp ship operator often has contracted cargoes that must be carried and seeks to maximize profit by carrying optional cargoes. Hence, tramp ships operate much like taxies following available cargo and not according to fixed route networks and itineraries as liner ships. Marine fuel is referred to as bunker and bunker costs constitute a significant part of daily operating costs. There can be great variations in bunker prices across bunker ports so it is important to carefully plan bunkering for each ship. As ships operate 24 h a day, they must refuel during operations. Therefore, route and schedule decisions affect the options for bunkering. Current practice is, however, to separate the two planning problems by first constructing fleet schedules and then plan bunkering for these fixed schedules. In this paper we explore the effects of integrating bunker planning in the routing and scheduling phase for a tramp operator sailing full shiploads, i.e. carrying at most one cargo onboard each ship at a time. We present a mixed integer programming formulation for the integrated problem of optimally routing, scheduling and bunkering a tramp fleet carrying full shiploads. Aside from bunker integration, this model also extends standard formulations by using load dependent costs, speed and bunker consumption. We devise a solution method based on column generation with a dynamic programming algorithm to generate columns. The method is heuristic mainly due to discretization of the continuous bunker purchase variables. We show that the integrated planning approach can increase profits and that the decision of which cargoes to carry and on which ships is affected by the bunker integration and by changes in the bunker prices.
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The microtubule (MT) plus-end-tracking proteins (+TIPs) belonging to the end binding (EB) protein family have been studied extensively in the context of cytoplasmic MTs and were shown to play pivotal roles in regulating MT dynamics and in... more
The microtubule (MT) plus-end-tracking proteins (+TIPs) belonging to the end binding (EB) protein family have been studied extensively in the context of cytoplasmic MTs and were shown to play pivotal roles in regulating MT dynamics and in recruiting other +TIPs to MT ends. Early studies in the green alga Chlamydomonas reinhardtii showed that EB1 localizes to the distal flagellum tip and the basal body, and subsequent studies using green fluorescent protein-tagged fusion proteins have demonstrated similar localization of EBs in other ciliated organisms, including mammalian cells as demonstrated here. Functional analysis of EBs in cultured mammalian cells revealed that EB1 and EB3 are required for biogenesis of primary cilia. Although mammalian EB3 localizes to the tip of some cilia and induces cilium elongation, EBs primarily seem to promote ciliogenesis via MT minus-end anchoring at the basal body, in turn facilitating vesicular trafficking to the cilium base. Moreover, mammalian EBs were shown to interact with several proteins implicated in MT minus-end anchoring and/or vesicular trafficking to cilia. Recent work suggests that apart from EBs, additional +TIPs may be present at the distal tip of cilia where they could regulate axoneme assembly, stability, or disassembly.
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... cointegration rank, the number of stationary vectors is estimated by testing successively, starting with ... procedure in this case is to respecify the VAR in differences thereby obtaining ... Thesimultaneous testing of the presence... more
... cointegration rank, the number of stationary vectors is estimated by testing successively, starting with ... procedure in this case is to respecify the VAR in differences thereby obtaining ... Thesimultaneous testing of the presence of cointegration and no Granger causality is discussed ...
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Research Interests: Multidisciplinary, Cell line, Humans, Blood Glucose, Insulin, and 16 moreGliadin, Mice, G protein-coupled receptors, Female, Animals, Peptides, PLoS one, Insulinoma, Rats, Body Weight, Molecular weight, Amino Acid Sequence, Action Potentials, Diazoxide, islets of Langerhans, and Gene Expression Regulation
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Abstract The Double TSP with Multiple Stacks is a logistics problem where one must, using a container, transport a given number of orders from a set of pickup customers to a set of delivery customers at minimum cost. Each order... more
Abstract The Double TSP with Multiple Stacks is a logistics problem where one must, using a container, transport a given number of orders from a set of pickup customers to a set of delivery customers at minimum cost. Each order corresponds to the movement of one pallet, all pickups must be completed before the first delivery, and the container cannot be repacked once packed. In this paper we improve the previously proposed exact method of Lusby et al.(Int Trans Oper Res 17 (2010), 637–652) through an additional preprocessing ...
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Abstract An ontology is a classification model for a given domain. In information retrieval, ontologies are used to perform broad searches. An ontology can be visualized as nodes and edges. Each node represents an element and each edge a... more
Abstract An ontology is a classification model for a given domain. In information retrieval, ontologies are used to perform broad searches. An ontology can be visualized as nodes and edges. Each node represents an element and each edge a relation between a parent and a child element. Working with an ontology becomes easier with a visual representation. An idea is to use the expressive power of 3D representation to provide visualization for the user. In this paper, we propose a new method for positioning the elements of the visualized ...
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The Vehicle Routing Problem with Time Windows is a generalization of the well known capacity constrained Vehicle Routing Problem. A homogeneous fleet of vehicles has to service a set of customers. The service of the customers can only... more
The Vehicle Routing Problem with Time Windows is a generalization of the well known capacity constrained Vehicle Routing Problem. A homogeneous fleet of vehicles has to service a set of customers. The service of the customers can only start within a well-defined time interval ...
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Abstract In this paper we present a new scheduling problem and describe a shortest path based heuristic as well as a dynamic programming based exact optimization algorithm to solve it. The Selective Multi-Category Parallel-Servicing... more
Abstract In this paper we present a new scheduling problem and describe a shortest path based heuristic as well as a dynamic programming based exact optimization algorithm to solve it. The Selective Multi-Category Parallel-Servicing Problem (SMCPSP) arises when a set of jobs has to be scheduled on a server (machine) with limited capacity. Each job requests service in a prespecified time window and belongs to a certain category. Jobs may be serviced partially, incurring a penalty; however, only jobs of the same category can be ...
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A constitutive relation based on floe collisions as introduced by Shen et al. (1986) is used in a sea ice model for calculating the internal ice force. The formulation is generalized to collisions of discs of two sizes and of multiple... more
A constitutive relation based on floe collisions as introduced by Shen et al. (1986) is used in a sea ice model for calculating the internal ice force. The formulation is generalized to collisions of discs of two sizes and of multiple sizes and a comparison with existing constitutive ...
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A mesoscale dynamic thermodynamic sea ice model is presented. The model differs from the large scale sea ice model [Hibler, 1979; Parkinson and Washington, 1979] in both the dynamic and thermodynamic parts. In the dynamic calculation, a... more
A mesoscale dynamic thermodynamic sea ice model is presented. The model differs from the large scale sea ice model [Hibler, 1979; Parkinson and Washington, 1979] in both the dynamic and thermodynamic parts. In the dynamic calculation, a constitutive relation based on ice floe collision is used for the determination of the internal ice force in the Marginal Ice Zone (MIZ), while in the thermodynamic calculation, a three-level approach for the ice thickness distribution is adopted instead of the common two-level approach [Hibler, 1979]. ...
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The double travelling salesman problem (TSP) with multiple stacks (DTSPMS) is a pickup and delivery problem in which all pickups must be completed before any deliveries can be made. The problem originates from a real-life application... more
The double travelling salesman problem (TSP) with multiple stacks (DTSPMS) is a pickup and delivery problem in which all pickups must be completed before any deliveries can be made. The problem originates from a real-life application where a 40-foot container (configured ...