The Experts below are selected from a list of 48 Experts worldwide ranked by ideXlab platform
N. Von Der Weid - One of the best experts on this subject based on the ideXlab platform.
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Haemophilia Registry of the Medical Committee of the Swiss Haemophilia Society
Hämostaseologie, 2010Co-Authors: N. Von Der WeidAbstract:SummaryThe Swiss Haemophilia Registry of the Medical Committee of the Swiss Haemophilia Society started in 1996 but was set as an internet-based, double password-Protected Facility in the year 2000. With the inclusion of patients’ data from two new centres in 2009, we assume a coverage rate of about 90% of all patients with inherited bleeding disorders in our country. Data concerning the phenotype and genotype of the disorder, its severity, its therapy, the prevalence of inhibitors are readily available to the registered users, allowing quality control of haemophilia therapy at a national level, but also rapid care of the patient visiting the emergency room of another treatment centre. Basing on the available data, about two thirds of the WFH global survey can be answered; the mortality statistics shows that bleeding remains a cause of death in haemophiliacs, also in the 21th century. The Registry allows for comparisons with international datasets, especially with respect to treatment (prophylaxis vs. on-demand therapy), factor consumption and costs.
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Haemophilia registry of the medical committee of the Swiss Haemophilia Society. Update and annual survey 2009.
Hamostaseologie, 2010Co-Authors: N. Von Der WeidAbstract:The Swiss Haemophilia Registry of the Medical Committee of the Swiss Haemophilia Society started in 1996 but was set as an internet-based, double password-Protected Facility in the year 2000. With the inclusion of patients' data from two new centres in 2009, we assume a coverage rate of about 90% of all patients with inherited bleeding disorders in our country. Data concerning the phenotype and genotype of the disorder, its severity, its therapy, the prevalence of inhibitors are readily available to the registered users, allowing quality control of haemophilia therapy at a national level, but also rapid care of the patient visiting the emergency room of another treatment centre. Basing on the available data, about two thirds of the WFH global survey can be answered; the mortality statistics shows that bleeding remains a cause of death in haemophiliacs, also in the 21th century. The Registry allows for comparisons with international datasets, especially with respect to treatment (prophylaxis vs. on-demand therapy), factor consumption and costs.
Nuray Piyade - One of the best experts on this subject based on the ideXlab platform.
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A Bilevel p-median model for the planning and protection of critical facilities
Journal of Heuristics, 2013Co-Authors: Deniz Aksen, Necati Aras, Nuray PiyadeAbstract:The bilevel p -median problem for the planning and protection of critical facilities involves a static Stackelberg game between a system planner (defender) and a potential attacker. The system planner determines firstly where to open p critical service facilities, and secondly which of them to protect with a limited protection budget. Following this twofold action, the attacker decides which facilities to interdict simultaneously, where the maximum number of interdictions is fixed. Partial protection or interdiction of a Facility is not possible. Both the defender’s and the attacker’s actions have deterministic outcome; i.e., once Protected, a Facility becomes completely immune to interdiction, and an attack on an unProtected Facility destroys it beyond repair. Moreover, the attacker has perfect information about the location and protection status of facilities; hence he would never attack a Protected Facility. We formulate a bilevel integer program (BIP) for this problem, in which the defender takes on the leader’s role and the attacker acts as the follower. We propose and compare three different methods to solve the BIP. The first method is an optimal exhaustive search algorithm with exponential time complexity. The second one is a two-phase tabu search heuristic developed to overcome the first method’s impracticality on large-sized problem instances. Finally, the third one is a sequential solution method in which the defender’s location and protection decisions are separated. The efficiency of these three methods is extensively tested on 75 randomly generated instances each with two budget levels. The results show that protection budget plays a significant role in maintaining the service accessibility of critical facilities in the worst-case interdiction scenario.
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A Bilevel p-median model for the planning and protection of critical facilities
Journal of Heuristics, 2011Co-Authors: Deniz Aksen, Necati Aras, Nuray PiyadeAbstract:The bilevel p-median problem for the planning and protection of critical facilities involves a static Stackelberg game between a system planner (defender) and a potential attacker. The system planner determines firstly where to open p critical service facilities, and secondly which of them to protect with a limited protection budget. Following this twofold action, the attacker decides which facilities to interdict simultaneously, where the maximum number of interdictions is fixed. Partial protection or interdiction of a Facility is not possible. Both the defender's and the attacker's actions have deterministic outcome; i.e., once Protected, a Facility becomes completely immune to interdiction, and an attack on an unProtected Facility destroys it beyond repair. Moreover, the attacker has perfect information about the location and protection status of facilities; hence he would never attack a Protected Facility. We formulate a bilevel integer program (BIP) for this problem, in which the defender takes on the leader's role and the attacker acts as the follower. We propose and compare three different methods to solve the BIP. The first method is an optimal exhaustive search algorithm with exponential time complexity. The second one is a two-phase tabu search heuristic developed to overcome the first method's impracticality on large-sized problem instances. Finally, the third one is a sequential solution method in which the defender's location and protection decisions are separated. The efficiency of these three methods is extensively tested on 75 randomly generated instances each with two budget levels. The results show that protection budget plays a significant role in maintaining the service accessibility of critical facilities in the worst-case interdiction scenario.
Deniz Aksen - One of the best experts on this subject based on the ideXlab platform.
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A Bilevel p-median model for the planning and protection of critical facilities
Journal of Heuristics, 2013Co-Authors: Deniz Aksen, Necati Aras, Nuray PiyadeAbstract:The bilevel p -median problem for the planning and protection of critical facilities involves a static Stackelberg game between a system planner (defender) and a potential attacker. The system planner determines firstly where to open p critical service facilities, and secondly which of them to protect with a limited protection budget. Following this twofold action, the attacker decides which facilities to interdict simultaneously, where the maximum number of interdictions is fixed. Partial protection or interdiction of a Facility is not possible. Both the defender’s and the attacker’s actions have deterministic outcome; i.e., once Protected, a Facility becomes completely immune to interdiction, and an attack on an unProtected Facility destroys it beyond repair. Moreover, the attacker has perfect information about the location and protection status of facilities; hence he would never attack a Protected Facility. We formulate a bilevel integer program (BIP) for this problem, in which the defender takes on the leader’s role and the attacker acts as the follower. We propose and compare three different methods to solve the BIP. The first method is an optimal exhaustive search algorithm with exponential time complexity. The second one is a two-phase tabu search heuristic developed to overcome the first method’s impracticality on large-sized problem instances. Finally, the third one is a sequential solution method in which the defender’s location and protection decisions are separated. The efficiency of these three methods is extensively tested on 75 randomly generated instances each with two budget levels. The results show that protection budget plays a significant role in maintaining the service accessibility of critical facilities in the worst-case interdiction scenario.
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A Bilevel p-median model for the planning and protection of critical facilities
Journal of Heuristics, 2011Co-Authors: Deniz Aksen, Necati Aras, Nuray PiyadeAbstract:The bilevel p-median problem for the planning and protection of critical facilities involves a static Stackelberg game between a system planner (defender) and a potential attacker. The system planner determines firstly where to open p critical service facilities, and secondly which of them to protect with a limited protection budget. Following this twofold action, the attacker decides which facilities to interdict simultaneously, where the maximum number of interdictions is fixed. Partial protection or interdiction of a Facility is not possible. Both the defender's and the attacker's actions have deterministic outcome; i.e., once Protected, a Facility becomes completely immune to interdiction, and an attack on an unProtected Facility destroys it beyond repair. Moreover, the attacker has perfect information about the location and protection status of facilities; hence he would never attack a Protected Facility. We formulate a bilevel integer program (BIP) for this problem, in which the defender takes on the leader's role and the attacker acts as the follower. We propose and compare three different methods to solve the BIP. The first method is an optimal exhaustive search algorithm with exponential time complexity. The second one is a two-phase tabu search heuristic developed to overcome the first method's impracticality on large-sized problem instances. Finally, the third one is a sequential solution method in which the defender's location and protection decisions are separated. The efficiency of these three methods is extensively tested on 75 randomly generated instances each with two budget levels. The results show that protection budget plays a significant role in maintaining the service accessibility of critical facilities in the worst-case interdiction scenario.
Yousef Alostaz - One of the best experts on this subject based on the ideXlab platform.
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Blast Loads Behind Blast Walls: Are They Low Enough?
Structures Congress 2014, 2014Co-Authors: Yousef AlostazAbstract:One of the greatest challenges blast engineers face is securing enough standoff for facilities that need to be Protected against attacks by vehicle-borne bombs. One solution might require the use of a perimeter blast wall. Depending on their location relative to the Protected Facility and the standoff distance to the bomb, perimeter blast walls might reduce the blast pressure and impulse from a vehicle bomb. Generally, erecting a blast wall at some distance from the building might provide no appreciable increase in protection for the majority of buildings. However, constructing a blast wall immediately in front of the building might provide significant protection. The blast wall effectively reduces the pressure from a reflected pulse to an incident pulse, permitting reduced safe standoff distances. Additionally, a properly designed perimeter blast wall will stop the effects of fragmentation. Empirical equations, developed by military researchers, might be used to predict the blast pressure and impulse reduction capabilities of a perimeter wall. However, the application of such equations is severely limited by the test parameters used in the equation development. Some design guidelines require that blast walls have a height equal to 1.5 times the Protected structure height, and a width equal to twice the Protected structure width. Furthermore, the wall must be constructed no further than one story height from the Protected face of the building. Hence, blast walls can be massive and aesthetically not unpleasant. This paper will examine the effectiveness of blast walls in reducing blast pressures and impulses behind the walls. Three-dimensional, Computational Fluid Dynamic (CFD) simulations will be used to calculate the blast pressures for various blast environments. Where applicable, the calculated blast loads will be compared with those obtained using the empirical approach.
Necati Aras - One of the best experts on this subject based on the ideXlab platform.
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A Bilevel p-median model for the planning and protection of critical facilities
Journal of Heuristics, 2013Co-Authors: Deniz Aksen, Necati Aras, Nuray PiyadeAbstract:The bilevel p -median problem for the planning and protection of critical facilities involves a static Stackelberg game between a system planner (defender) and a potential attacker. The system planner determines firstly where to open p critical service facilities, and secondly which of them to protect with a limited protection budget. Following this twofold action, the attacker decides which facilities to interdict simultaneously, where the maximum number of interdictions is fixed. Partial protection or interdiction of a Facility is not possible. Both the defender’s and the attacker’s actions have deterministic outcome; i.e., once Protected, a Facility becomes completely immune to interdiction, and an attack on an unProtected Facility destroys it beyond repair. Moreover, the attacker has perfect information about the location and protection status of facilities; hence he would never attack a Protected Facility. We formulate a bilevel integer program (BIP) for this problem, in which the defender takes on the leader’s role and the attacker acts as the follower. We propose and compare three different methods to solve the BIP. The first method is an optimal exhaustive search algorithm with exponential time complexity. The second one is a two-phase tabu search heuristic developed to overcome the first method’s impracticality on large-sized problem instances. Finally, the third one is a sequential solution method in which the defender’s location and protection decisions are separated. The efficiency of these three methods is extensively tested on 75 randomly generated instances each with two budget levels. The results show that protection budget plays a significant role in maintaining the service accessibility of critical facilities in the worst-case interdiction scenario.
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A Bilevel p-median model for the planning and protection of critical facilities
Journal of Heuristics, 2011Co-Authors: Deniz Aksen, Necati Aras, Nuray PiyadeAbstract:The bilevel p-median problem for the planning and protection of critical facilities involves a static Stackelberg game between a system planner (defender) and a potential attacker. The system planner determines firstly where to open p critical service facilities, and secondly which of them to protect with a limited protection budget. Following this twofold action, the attacker decides which facilities to interdict simultaneously, where the maximum number of interdictions is fixed. Partial protection or interdiction of a Facility is not possible. Both the defender's and the attacker's actions have deterministic outcome; i.e., once Protected, a Facility becomes completely immune to interdiction, and an attack on an unProtected Facility destroys it beyond repair. Moreover, the attacker has perfect information about the location and protection status of facilities; hence he would never attack a Protected Facility. We formulate a bilevel integer program (BIP) for this problem, in which the defender takes on the leader's role and the attacker acts as the follower. We propose and compare three different methods to solve the BIP. The first method is an optimal exhaustive search algorithm with exponential time complexity. The second one is a two-phase tabu search heuristic developed to overcome the first method's impracticality on large-sized problem instances. Finally, the third one is a sequential solution method in which the defender's location and protection decisions are separated. The efficiency of these three methods is extensively tested on 75 randomly generated instances each with two budget levels. The results show that protection budget plays a significant role in maintaining the service accessibility of critical facilities in the worst-case interdiction scenario.
