The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Ivana Ljubić - One of the best experts on this subject based on the ideXlab platform.
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INOC - A node splitting technique for two level network design problems with transition nodes
Lecture Notes in Computer Science, 2011Co-Authors: Stefan Gollowitzer, Luis Gouveia, Ivana LjubićAbstract:The Two Level Network Design (TLND) problem arises when local broadband access networks are planned in areas, where no existing infrastructure can be used, i.e., in the so-called greenfield deployments. Mixed strategies of Fiber-To-The-Home and Fiber-To-The-Curb, i.e., some customers are served by copper cables, some by fiber optic lines, can be modeled by an Extension of the TLND. We are given two types of customers (primary and secondary), an additional set of Steiner nodes and fixed costs for installing either a primary or a secondary technology on each edge. The TLND problem seeks a minimum cost connected subgraph obeying a tree-tree topology, i.e., the primary nodes are connected by a rooted primary tree; the secondary nodes can be connected using both primary and secondary technology. In this paper we study an Important Extension of TLND in which additional transition costs need to be paid for intermediate facilities placed at the transition nodes, i.e., nodes where the change of technology takes place. The introduction of transition node costs leads to a problem with a rich structure permitting us to put in evidence reformulation techniques such as modeling in higher dimensional graphs (which in this case are based on a node splitting technique). We first provide a compact way of modeling intermediate facilities. We then present several generalizations of the facility-based inequalities involving an exponential number of constraints. Finally we show how to model the problem in an extended graph based on node splitting. Our main result states that the connectivity constraints on the splitted graph, projected back into the space of the variables of the original model, provide a new family of inequalities that implies, and even strictly dominates, all previously described cuts. We also provide a polynomial time separation algorithm for the more general cuts by calculating maximum flows on the splitted graph. We compare the proposed models both theoretically and computationally.
Adam A. Blackler - One of the best experts on this subject based on the ideXlab platform.
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From Boondoggle to Settlement Colony: Hendrik Witbooi and the Evolution of Germany's Imperial Project in Southwest Africa, 1884–1894
Central European History, 2017Co-Authors: Adam A. BlacklerAbstract:In the span of ten years, what started as a minor commercial enterprise in a faraway African territory grew into an Important Extension of the German state. This article reorients our understanding of the relationship between the Kaiserreich and its overseas empire, specifically with a focus on Captain Hendrik Witbooi and on how the Witbooi Namaqua he led influenced the evolution of German imperial rule in Southwest Africa between 1884 and 1894. Witbooi's refusal to accept imperial authority compelled colonial officials to confront their administrative limitations in the colony. When the facade of imperial fantasy gave way to colonial reality, German administrators expanded the size and scope of the imperial government to subdue the Namaqua. The article emphasizes the appointments of Landeshauptmann Curt von Francois and Governor Theodor Leutwein as critical examples of Witbooi's impact on imperial policy, as well as the colonial administration's embrace of military violence to attain German supremacy in Southwest Africa. An emphasis on the Witbooi Namaqua illustrates the prominent role of Africans in German colonial history and exposes how peoples in distant places like Windhoek and Otjimbingwe manipulated official efforts to control and exploit the colony.
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from boondoggle to settlement colony hendrik witbooi and the evolution of germany s imperial project in southwest africa 1884 1894
Central European History, 2017Co-Authors: Adam A. BlacklerAbstract:In the span of ten years, what started as a minor commercial enterprise in a faraway African territory grew into an Important Extension of the German state. This article reorients our understanding of the relationship between the Kaiserreich and its overseas empire, specifically with a focus on Captain Hendrik Witbooi and on how the Witbooi Namaqua he led influenced the evolution of German imperial rule in Southwest Africa between 1884 and 1894. Witbooi's refusal to accept imperial authority compelled colonial officials to confront their administrative limitations in the colony. When the facade of imperial fantasy gave way to colonial reality, German administrators expanded the size and scope of the imperial government to subdue the Namaqua. The article emphasizes the appointments of Landeshauptmann Curt von Francois and Governor Theodor Leutwein as critical examples of Witbooi's impact on imperial policy, as well as the colonial administration's embrace of military violence to attain German supremacy in Southwest Africa. An emphasis on the Witbooi Namaqua illustrates the prominent role of Africans in German colonial history and exposes how peoples in distant places like Windhoek and Otjimbingwe manipulated official efforts to control and exploit the colony.
Stefan Gollowitzer - One of the best experts on this subject based on the ideXlab platform.
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a node splitting technique for two level network design problems with transition nodes
INOC'11 Proceedings of the 5th international conference on Network optimization, 2011Co-Authors: Stefan Gollowitzer, Luis Gouveia, Ivana LjubicAbstract:The Two Level Network Design (TLND) problem arises when local broadband access networks are planned in areas, where no existing infrastructure can be used, i.e., in the so-called greenfield deployments. Mixed strategies of Fiber-To-The-Home and Fiber-To-The-Curb, i.e., some customers are served by copper cables, some by fiber optic lines, can be modeled by an Extension of the TLND. We are given two types of customers (primary and secondary), an additional set of Steiner nodes and fixed costs for installing either a primary or a secondary technology on each edge. The TLND problem seeks a minimum cost connected subgraph obeying a tree-tree topology, i.e., the primary nodes are connected by a rooted primary tree; the secondary nodes can be connected using both primary and secondary technology. In this paper we study an Important Extension of TLND in which additional transition costs need to be paid for intermediate facilities placed at the transition nodes, i.e., nodes where the change of technology takes place. The introduction of transition node costs leads to a problem with a rich structure permitting us to put in evidence reformulation techniques such as modeling in higher dimensional graphs (which in this case are based on a node splitting technique). We first provide a compact way of modeling intermediate facilities. We then present several generalizations of the facility-based inequalities involving an exponential number of constraints. Finally we show how to model the problem in an extended graph based on node splitting. Our main result states that the connectivity constraints on the splitted graph, projected back into the space of the variables of the original model, provide a new family of inequalities that implies, and even strictly dominates, all previously described cuts. We also provide a polynomial time separation algorithm for the more general cuts by calculating maximum flows on the splitted graph. We compare the proposed models both theoretically and computationally.
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INOC - A node splitting technique for two level network design problems with transition nodes
Lecture Notes in Computer Science, 2011Co-Authors: Stefan Gollowitzer, Luis Gouveia, Ivana LjubićAbstract:The Two Level Network Design (TLND) problem arises when local broadband access networks are planned in areas, where no existing infrastructure can be used, i.e., in the so-called greenfield deployments. Mixed strategies of Fiber-To-The-Home and Fiber-To-The-Curb, i.e., some customers are served by copper cables, some by fiber optic lines, can be modeled by an Extension of the TLND. We are given two types of customers (primary and secondary), an additional set of Steiner nodes and fixed costs for installing either a primary or a secondary technology on each edge. The TLND problem seeks a minimum cost connected subgraph obeying a tree-tree topology, i.e., the primary nodes are connected by a rooted primary tree; the secondary nodes can be connected using both primary and secondary technology. In this paper we study an Important Extension of TLND in which additional transition costs need to be paid for intermediate facilities placed at the transition nodes, i.e., nodes where the change of technology takes place. The introduction of transition node costs leads to a problem with a rich structure permitting us to put in evidence reformulation techniques such as modeling in higher dimensional graphs (which in this case are based on a node splitting technique). We first provide a compact way of modeling intermediate facilities. We then present several generalizations of the facility-based inequalities involving an exponential number of constraints. Finally we show how to model the problem in an extended graph based on node splitting. Our main result states that the connectivity constraints on the splitted graph, projected back into the space of the variables of the original model, provide a new family of inequalities that implies, and even strictly dominates, all previously described cuts. We also provide a polynomial time separation algorithm for the more general cuts by calculating maximum flows on the splitted graph. We compare the proposed models both theoretically and computationally.
M. Lewitowicz - One of the best experts on this subject based on the ideXlab platform.
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Low-energy reactions, moments and beta-decays with radioactive beams for nuclear structure and astrophysics problems. Results and perspectives with SPIRAL2
2010Co-Authors: M. LewitowiczAbstract:The SPIRAL 2 project, an Important Extension of the GANIL facility which has recently entered in the construction phase is shortly presented. The physics case of the facility based is on the use of high-intensity stable and radioactive beams. Expected performances and main technical parameters of the facility are introduced. Examples of physics topics and related measurements are discussed in the context of new experimental halls and devices to be constructed in order to fully explore the possibilities offered by this advanced Radioactive Ion Beam facility.
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The SPIRAL2 Project: Physics and Challenges
2008Co-Authors: M. LewitowiczAbstract:The SPIRAL2 project, an Important Extension of the GANIL facility and one of the ESFRI list European research infrastructures entered recently in the construction phase. In the following, a physics case of the facility based on a use of high intensity stable and radioactive beams is presented. Expected performances and main technical parameters of the facility as well as planned new experimental areas and detectors are introduced.
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The SPIRAL 2 Project
2008Co-Authors: M. LewitowiczAbstract:The SPIRAL 2 project, an Important Extension of the GANIL facility which entered recently in the construction phase is shortly presented. The physics case of the facility is based on the use of high intensity stable and radioactive beams. Expected performances and main technical parameters of the facility as well as planned new experimental areas and detectors are introduced.
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The SPIRAL 2 Project
AIP Conference Proceedings, 2008Co-Authors: M. Lewitowicz, Ismail Boztosun, A. B. BalantekinAbstract:International audienceThe SPIRAL 2 project, an Important Extension of the GANIL facility which entered recently in the construction phase is shortly presented. The physics case of the facility is based on the use of high intensity stable and radioactive beams. Expected performances and main technical parameters of the facility as well as planned new experimental areas and detectors are introduced
Luis Gouveia - One of the best experts on this subject based on the ideXlab platform.
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a node splitting technique for two level network design problems with transition nodes
INOC'11 Proceedings of the 5th international conference on Network optimization, 2011Co-Authors: Stefan Gollowitzer, Luis Gouveia, Ivana LjubicAbstract:The Two Level Network Design (TLND) problem arises when local broadband access networks are planned in areas, where no existing infrastructure can be used, i.e., in the so-called greenfield deployments. Mixed strategies of Fiber-To-The-Home and Fiber-To-The-Curb, i.e., some customers are served by copper cables, some by fiber optic lines, can be modeled by an Extension of the TLND. We are given two types of customers (primary and secondary), an additional set of Steiner nodes and fixed costs for installing either a primary or a secondary technology on each edge. The TLND problem seeks a minimum cost connected subgraph obeying a tree-tree topology, i.e., the primary nodes are connected by a rooted primary tree; the secondary nodes can be connected using both primary and secondary technology. In this paper we study an Important Extension of TLND in which additional transition costs need to be paid for intermediate facilities placed at the transition nodes, i.e., nodes where the change of technology takes place. The introduction of transition node costs leads to a problem with a rich structure permitting us to put in evidence reformulation techniques such as modeling in higher dimensional graphs (which in this case are based on a node splitting technique). We first provide a compact way of modeling intermediate facilities. We then present several generalizations of the facility-based inequalities involving an exponential number of constraints. Finally we show how to model the problem in an extended graph based on node splitting. Our main result states that the connectivity constraints on the splitted graph, projected back into the space of the variables of the original model, provide a new family of inequalities that implies, and even strictly dominates, all previously described cuts. We also provide a polynomial time separation algorithm for the more general cuts by calculating maximum flows on the splitted graph. We compare the proposed models both theoretically and computationally.
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INOC - A node splitting technique for two level network design problems with transition nodes
Lecture Notes in Computer Science, 2011Co-Authors: Stefan Gollowitzer, Luis Gouveia, Ivana LjubićAbstract:The Two Level Network Design (TLND) problem arises when local broadband access networks are planned in areas, where no existing infrastructure can be used, i.e., in the so-called greenfield deployments. Mixed strategies of Fiber-To-The-Home and Fiber-To-The-Curb, i.e., some customers are served by copper cables, some by fiber optic lines, can be modeled by an Extension of the TLND. We are given two types of customers (primary and secondary), an additional set of Steiner nodes and fixed costs for installing either a primary or a secondary technology on each edge. The TLND problem seeks a minimum cost connected subgraph obeying a tree-tree topology, i.e., the primary nodes are connected by a rooted primary tree; the secondary nodes can be connected using both primary and secondary technology. In this paper we study an Important Extension of TLND in which additional transition costs need to be paid for intermediate facilities placed at the transition nodes, i.e., nodes where the change of technology takes place. The introduction of transition node costs leads to a problem with a rich structure permitting us to put in evidence reformulation techniques such as modeling in higher dimensional graphs (which in this case are based on a node splitting technique). We first provide a compact way of modeling intermediate facilities. We then present several generalizations of the facility-based inequalities involving an exponential number of constraints. Finally we show how to model the problem in an extended graph based on node splitting. Our main result states that the connectivity constraints on the splitted graph, projected back into the space of the variables of the original model, provide a new family of inequalities that implies, and even strictly dominates, all previously described cuts. We also provide a polynomial time separation algorithm for the more general cuts by calculating maximum flows on the splitted graph. We compare the proposed models both theoretically and computationally.
