An important class of problems in manufacturing system are those in which there is an item to be ... more An important class of problems in manufacturing system are those in which there is an item to be produced, a set of components which can be assembled together in order to obtain the wanted item, and a set of machines which are capable to perform the assembly operations. Here we consider the case in which one wants to find an optimal list of assembly operations. After discussing several optimality criteria, we address the problem in which the assembly operations are to be chosen in such a way that they can be scheduled on the available machines at minimum makespan. We show that these problems can be quite naturally modelled making use of Directed Hypergraphs, and describe a general heuristics, showing that in a particular but still relevant case, it yields solutions whose relative error is bounded. We present also a special class of assembly problems which can be solved in polynomial time by means of hyperpath computations. Subject classifications : Production/scheduling: pl...
1 Introduction On the Dispatching Problem Federico Di Miele Giorgio Gallo October 18, 2000 Most o... more 1 Introduction On the Dispatching Problem Federico Di Miele Giorgio Gallo October 18, 2000 Most often, space is the scarce resource in Bus Depots located in congested urban areas: vehicles arriving at the end of their trips are packed together in a rather small space. That implies that, when a vehicle has to leave to start a new trip, most often, other vehicles have to be moved to clear the way. Here a new model, based on #Min Non Crossing Matching# and #Generalized Assignment#, is presented to allocate parking spaces to vehicles in a Depot in order to minimize the shunting cost. The results obtained applying our approach to a real life case are discussed. Among the many di#erent problems which arise in the day-by-day operations of urban transportation companies, most of them leading to the formulation of challenging Mathematical Programming problems, one which, at least so far, has attracted rather little attention is the so called #Bus Dispatching Problem#. This is the problem of ...
ABSTRACT The problem of optimally locating copies of programs and files in a distributed data bas... more ABSTRACT The problem of optimally locating copies of programs and files in a distributed data base is considered. The problem is formulated as a linear integer programming problem with a quite special structure, where the objective function represents the total storage and communication cost of the operations to be performed in the database. An approach, based on Benders’ decomposition, to solve the problem is illustrated and a heuristic algorithm together with an experimental analysis of its efficiency is presented.
... Peace Studies has to address, a holistic and interdisciplinary cultural and scientific backgr... more ... Peace Studies has to address, a holistic and interdisciplinary cultural and scientific background, such ... Similarly, the Islamic salam and the Sanskrit shanti have extended meanings. ... They are dynamic processes in which structure, attitudes and behaviour are constantly changing ...
The discourse on Ethics in Operations Research/Management Sci- ence has many aspects. Among them ... more The discourse on Ethics in Operations Research/Management Sci- ence has many aspects. Among them there is the ethical responsibil- ity the OR/MS community faces in a world in which the widespread presence structural violence makes the construction of a peaceful and sustainable social order a very challenging task, and puts at risk the very survival of human kind. In this
Transportation Research Part B: Methodological, 1982
... workdays which assign a driver to each bus in the timetable and respect ... D. (1981), HASTUS... more ... workdays which assign a driver to each bus in the timetable and respect ... D. (1981), HASTUS 1: A Mathematical Programming Approach to the Bus Driver Scheduling Problem. ComputerScheduling of Public Transport, Urban Passenger Vehicle and Crew Scheduling, (Edited by ...
An important class of problems in manufacturing are those in which there is an item to be produce... more An important class of problems in manufacturing are those in which there is an item to be produced, a set of components which can be assembled together to produce the item, and a set of identical machines capable to perform the assembly operations. After discussing ...
The problem of finding a work assignment for airline crew members in a given time horizon, is add... more The problem of finding a work assignment for airline crew members in a given time horizon, is addressed. In the literature such a problem is usually referred to as the Airline Crew Rostering problem and consists of constructing monthly schedules for crew members by assigning ...
An important class of problems in manufacturing system are those in which there is an item to be ... more An important class of problems in manufacturing system are those in which there is an item to be produced, a set of components which can be assembled together in order to obtain the wanted item, and a set of machines which are capable to perform the assembly ...
The remarkable pioneering work of Lewis Fry Richardson has started the theoretical analysis of t... more The remarkable pioneering work of Lewis Fry Richardson has started the theoretical analysis of the action-reaction processes leading to the onset of violent conflicts. His work, developed between the two world wars, has started receiving recognition only with the birth of Peace and Conflict Studies in the aftermath of WWII. Here the main model proposed by Richardson will be presented and discussed, together with some of its extensions and derivations. Particular attention shall be dedicated to the epistemological analysis of these models.
Starting from a critical analysis of the US intervention in Afghanistan in response to the 11 Sep... more Starting from a critical analysis of the US intervention in Afghanistan in response to the 11 September 2001 events, this paper seeks to propose a different approach to terrorism/ counterterrorism analysis consisting in putting at the forefront the discursive dimension of the phenomenon through the lens of critical discourse analysis and in grounding it in a system thinking approach. The main argument is that ‘terrorism’ cannot be understood outside a context, language and culture, and that to be fully grasped as a dynamic phenomenon, it has to be framed in a systems perspective. Among the key elements of system thinking that can enhance the understanding of terrorism are boundary definition, casual loops and feedbacks, delays, emergent properties and overshoot-and-collapse.
An important class of problems in manufacturing system are those in which there is an item to be ... more An important class of problems in manufacturing system are those in which there is an item to be produced, a set of components which can be assembled together in order to obtain the wanted item, and a set of machines which are capable to perform the assembly operations. Here we consider the case in which one wants to find an optimal list of assembly operations. After discussing several optimality criteria, we address the problem in which the assembly operations are to be chosen in such a way that they can be scheduled on the available machines at minimum makespan. We show that these problems can be quite naturally modelled making use of Directed Hypergraphs, and describe a general heuristics, showing that in a particular but still relevant case, it yields solutions whose relative error is bounded. We present also a special class of assembly problems which can be solved in polynomial time by means of hyperpath computations. Subject classifications : Production/scheduling: pl...
1 Introduction On the Dispatching Problem Federico Di Miele Giorgio Gallo October 18, 2000 Most o... more 1 Introduction On the Dispatching Problem Federico Di Miele Giorgio Gallo October 18, 2000 Most often, space is the scarce resource in Bus Depots located in congested urban areas: vehicles arriving at the end of their trips are packed together in a rather small space. That implies that, when a vehicle has to leave to start a new trip, most often, other vehicles have to be moved to clear the way. Here a new model, based on #Min Non Crossing Matching# and #Generalized Assignment#, is presented to allocate parking spaces to vehicles in a Depot in order to minimize the shunting cost. The results obtained applying our approach to a real life case are discussed. Among the many di#erent problems which arise in the day-by-day operations of urban transportation companies, most of them leading to the formulation of challenging Mathematical Programming problems, one which, at least so far, has attracted rather little attention is the so called #Bus Dispatching Problem#. This is the problem of ...
ABSTRACT The problem of optimally locating copies of programs and files in a distributed data bas... more ABSTRACT The problem of optimally locating copies of programs and files in a distributed data base is considered. The problem is formulated as a linear integer programming problem with a quite special structure, where the objective function represents the total storage and communication cost of the operations to be performed in the database. An approach, based on Benders’ decomposition, to solve the problem is illustrated and a heuristic algorithm together with an experimental analysis of its efficiency is presented.
... Peace Studies has to address, a holistic and interdisciplinary cultural and scientific backgr... more ... Peace Studies has to address, a holistic and interdisciplinary cultural and scientific background, such ... Similarly, the Islamic salam and the Sanskrit shanti have extended meanings. ... They are dynamic processes in which structure, attitudes and behaviour are constantly changing ...
The discourse on Ethics in Operations Research/Management Sci- ence has many aspects. Among them ... more The discourse on Ethics in Operations Research/Management Sci- ence has many aspects. Among them there is the ethical responsibil- ity the OR/MS community faces in a world in which the widespread presence structural violence makes the construction of a peaceful and sustainable social order a very challenging task, and puts at risk the very survival of human kind. In this
Transportation Research Part B: Methodological, 1982
... workdays which assign a driver to each bus in the timetable and respect ... D. (1981), HASTUS... more ... workdays which assign a driver to each bus in the timetable and respect ... D. (1981), HASTUS 1: A Mathematical Programming Approach to the Bus Driver Scheduling Problem. ComputerScheduling of Public Transport, Urban Passenger Vehicle and Crew Scheduling, (Edited by ...
An important class of problems in manufacturing are those in which there is an item to be produce... more An important class of problems in manufacturing are those in which there is an item to be produced, a set of components which can be assembled together to produce the item, and a set of identical machines capable to perform the assembly operations. After discussing ...
The problem of finding a work assignment for airline crew members in a given time horizon, is add... more The problem of finding a work assignment for airline crew members in a given time horizon, is addressed. In the literature such a problem is usually referred to as the Airline Crew Rostering problem and consists of constructing monthly schedules for crew members by assigning ...
An important class of problems in manufacturing system are those in which there is an item to be ... more An important class of problems in manufacturing system are those in which there is an item to be produced, a set of components which can be assembled together in order to obtain the wanted item, and a set of machines which are capable to perform the assembly ...
The remarkable pioneering work of Lewis Fry Richardson has started the theoretical analysis of t... more The remarkable pioneering work of Lewis Fry Richardson has started the theoretical analysis of the action-reaction processes leading to the onset of violent conflicts. His work, developed between the two world wars, has started receiving recognition only with the birth of Peace and Conflict Studies in the aftermath of WWII. Here the main model proposed by Richardson will be presented and discussed, together with some of its extensions and derivations. Particular attention shall be dedicated to the epistemological analysis of these models.
Starting from a critical analysis of the US intervention in Afghanistan in response to the 11 Sep... more Starting from a critical analysis of the US intervention in Afghanistan in response to the 11 September 2001 events, this paper seeks to propose a different approach to terrorism/ counterterrorism analysis consisting in putting at the forefront the discursive dimension of the phenomenon through the lens of critical discourse analysis and in grounding it in a system thinking approach. The main argument is that ‘terrorism’ cannot be understood outside a context, language and culture, and that to be fully grasped as a dynamic phenomenon, it has to be framed in a systems perspective. Among the key elements of system thinking that can enhance the understanding of terrorism are boundary definition, casual loops and feedbacks, delays, emergent properties and overshoot-and-collapse.
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Papers by Giorgio Gallo