Federico Malucelli

Federico Malucelli
Politecnico di Milano | Polimi · Department of Electronics, Information, and Bioengineering

About

144
Publications
15,993
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2,791
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Additional affiliations
November 1998 - December 2002
Politecnico di Milano
Position
  • Professor (Associate)

Publications

Publications (144)
Chapter
Basing on the operations of an Italian company, we model and solve a long-haul day-ahead transportation planning problem combining a number of features. Namely, we account for driver hours of service regulations, time-dependent travel times, time-dependent fuel consumption and refueling deviations. The latter stems from the fact that we consider no...
Article
The efficient management of metro lines is a major concern for public transport operators. Traditionally, metro lines are operated through regular timetables, that is, timetables where trains have a constant headway between all stations. In this paper, we propose a demand-driven metro timetabling strategy and elaborate exact solution methods for th...
Chapter
The students attending the Italian technical and vocational high schools have often a critical behavior towards the classes of Mathematics and Italian. They usually believe that these disciplines are sterile and marginal with respect to their main interests that rely on subjects characterizing their professional choice. We made some experiments int...
Article
Metro timetables are usually planned with a top-down approach. After dividing the day into different periods, the trains are scheduled between the terminals of the line with a fixed frequency per period. In this paper we adopt an alternative paradigm where trains are scheduled individually. The schedule is developed so as to best match the passenge...
Article
When demand for transportation is low or sparse, traditional transit cannot provide efficient and good-quality service, because of its fixed structure. For this reason, mass transit is evolving toward some degree of flexibility. Although the extension of Dial-a-Ride systems to general public meets such need of adaptability, it presents several draw...
Article
Full-text available
We report on a playful introduction of optimization in a high school. The final event of this experience has been an orienteering competition, in which the decision-making component plays a central role. This type of event has been very involving, and it boosted the interest of the students toward operations research. After summarizing the activiti...
Article
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In this paper we introduce the metro scheduling problem for a large event, e.g., a football match or a concert. We consider a metro line serving the venue of such an event. The ordinary metro timetable, which is typically based on constant headway between all stations, may lead to prolonged waiting when serving large events. To better handle such s...
Article
In the early years of school, pupils have a very positive approach towards any new topic. Very often, the first contact with mathematics in the Italian school risks giving a limited and somehow negative impression, generating long-lasting effects. In this paper, we report on a series of experiences carried out in a second-year class of a primary sc...
Article
Full-text available
We address the design of the lines of a Walking Bus service according to a new paradigm, where children are picked up at home. The scarcity of accompanying persons together with the limit on the length of the deviations from the shortest itinerary of each child make the problem different from the traditional school bus and walking bus design. We pr...
Article
Full-text available
Local public transport companies, especially in large cities, are facing every day the problem of managing delays and small disruptions. Disruption management is a well-established practice in airlines and railways. However, in local public transport the approaches to these problems have followed a different path, mainly focusing on holding and sho...
Article
Optimization is among the oldest mathematical applications in history: human nature tends to obtain the best results with the minimum effort, in many sectors. Nevertheless, optimization and operations research as mathematical disciplines struggle to find their place in high school syllabi and it is usually very hard to explain what they are about t...
Article
We study the problem of designing walking school bus lines (Pedibus) limiting the deviation with respect to the shortest path for each child, with the objective of minimizing the number of accompanying persons and the perceived risk of the selected trajectories. The problem is formulated using a path model and a column generation approach is propos...
Conference Paper
Due to the several benefits associated to cycling, the demand for bicycle devoted infrastructures has considerably raised in the last few years. Public resource investments into infrastructure provision increased to meet demand, despite of the lack of mature design and planning methodologies. Leisure intended cycling networks in particular, which a...
Article
We consider the problem of finding a shortest path in a directed graph with a quadratic objective function (the QSPP). We show that the QSPP cannot be approximated unless P=NP. For the case of a convex objective function, an n-approximation algorithm is presented, where n is the number of nodes in the graph, and APX-hardness is shown. Furthermore,...
Article
Full-text available
We address a particular pickup and delivery vehicle routing problem arising in the collection and disposal of bulky recyclable waste. Containers of different types, used to collect different waste materials, once full, must be picked up to be emptied at suitable disposal plants and replaced by empty containers alike. All requests must be served, an...
Article
In this paper we propose a new lower bounding procedure for the Quadratic Assignment Problem based on a generalization of the well-known Gilomore-Lawler procedure for a higher order reformulation. Computational results on some benchmark instances show the strength of the new approach compared with other lower bounds.
Conference Paper
Full-text available
Among the most effective actions to promote functional cycling, i.e., cycling as a mean of transport, infrastructure design and planning are major topics. Much less attention has been dedicated to the design and deployment of bikeways devoted to recreational cycling, despite the role of cycle routes in promoting cycle tourism, and the effectiveness...
Article
W e present the symmetric traveling salesman problem with generalized latency (TSP-GL) a new problem arising in the planning of the important class of semiflexible transit systems. The TSP-GL can be seen as a very challenging variant of the symmetric traveling salesman problem (S-TSP), where the objective function combines the usual cost of the cir...
Conference Paper
In this paper we propose a new lower bounding procedure for the Quadratic As- signment Problem based on a generalization of the well-known Gilomore-Lawler procedure for a higher order reformulation. Computational results on some bench- mark instances show the strength of the new approach compared with other lower bounds.
Article
In this paper we consider the Asymmetric Quadratic Traveling Salesman Problem. Given a directed graph and a function that maps every pair of consecutive arcs to a cost, the problem consists in finding a cycle that visits every vertex exactly once and such that the sum of the costs is minimal. We propose an extended Linear Programming formulation th...
Technical Report
We consider the problem of finding a shortest path in a directed graph with a quadratic objective function (the QSPP). We show that the QSPP cannot be approximated unless P=NP. For the case of a convex objective function, an n-approximation algorithm is presented, where n is the number of nodes in the graph, and APX-hardness is shown. Furthermore,...
Article
Full-text available
In this paper, we propose a decision support tool to assist a local public transportation company in tackling service delays and small disruptions. We discuss different ways to assess and improve the regularity of the service, and we propose a simulation based optimization system that can be effectively used in a real-time environment taking into a...
Article
Full-text available
This study concerns the optimal design of cycle tourist itineraries considering several classes of users. It builds upon a recent work which first introduced the problem of designing the most attractive itinerary for cycle tourists connecting a given origin to a given destination, subject to a budget and a time constraint. Starting from a network m...
Article
The Minimum Spanning Tree Problem (MSTP) is one of the most known combinatorial optimization problems. It concerns the determination of a minimum edge-cost subgraph spanning all the vertices of a given connected graph. The Quadratic Minimum Spanning Tree Problem (QMSTP) is a variant of the MSTP whose cost considers also the interaction between ever...
Conference Paper
Finding the shortest path in a directed graph is one of the most important combinatorial optimization problems, having applications in a wide range of fields. In its basic version, however, the problem fails to represent situations in which the value of the objective function is determined not only by the choice of each single arc, but also by the...
Article
Although sometimes it is necessary, no one likes to stay in a hospital, and patients who need to stay in bed but do not require constant medical surveillance prefer their own bed at home. At the same time, a patient in a hospital has a high cost for the community, that is not acceptable if the patient needs service only a few minutes a day. For the...
Article
Full-text available
Bicycles are becoming an increasingly popular mean of transport. Being healthy and affordable, they provide a sustainable alternative way of movement, for both leisure and work commuting. In both cases demand increases when bike devoted tracks are available. Providing bike trails that connect touristic spots is a cheap way of increasing the appeal...
Conference Paper
Full-text available
Information-Centric Networking (ICN) has recently gained momentum as a promising paradigm for the next-generation Internet architecture. The first prototypes for ICN-capable routers have already been developed, and network operators will soon have the opportunity to experience the advantages introduced by this technology. However, to migrate the de...
Article
The Reformulation Linearization Technique (RLT) applied to the Quadratic Assignment Problem yields mixed 0–1 programming problems whose linear relaxations provide a strong bound on the objective value. Nevertheless, in the high level RLT representations the computation requires much effort. In this paper we propose a new compact reformulation for e...
Article
When demand for transportation is low or sparse, traditional transit cannot provide efficient and good-quality service, due to its fixed structure. New transportation alternatives are therefore increasingly proposed, combining on-demand service adjustment capabilities to the regular route and schedule characteristics of traditional transit. Such so...
Conference Paper
In this paper we present a Column Generation approach to the Quadratic Traveling Salesman Problem. Given a graph and a function that maps every pair of edges to a cost, the problem consists in finding a cycle that visits every vertex exactly once and such that the sum of the costs over all pairs of consecutive edges of the cycle is minimum. We prop...
Chapter
Recommender systems play an increasingly important role in online applications characterized by a very large amount of data and help users to find what they need or prefer. Various approaches for recommender systems have been developed that utilize either demographic, content, or historical information. Among these methods, item-based collaborative...
Article
Full-text available
Demand-Adaptive Systems (DASs) display features of both traditional fixed-line bus services and purely on-demand systems such as dial-a-ride, that is, they offer demand-responsive services within the framework of traditional scheduled bus transportation. A DAS bus line serves a given set of compulsory stops according to a predefined schedule, which...
Article
We present a branching scheme for some vertex coloring problems based on a new graph operator called extension. The extension operator is used to generalize the branching scheme proposed by Zykov for the basic problem to a broad class of coloring problems, such as graph multicoloring, where each vertex requires a multiplicity of colors, graph bandw...
Conference Paper
Item-based collaborative filtering is one of most widely used and successful neighborhood-based collaborative recommendation approaches. The main idea of item-based algorithms is to compute predictions using the similarity between items. In such approaches, two items are similar if several users of the system have rated these items in a similar fas...
Article
Although sometimes it is necessary, no one likes to stay in a hospital, and patients who need to stay in bed but do not require constant medical surveillance prefer their own bed at home. At the same time, a patient in a hospital has a high cost for the community, that is not acceptable if the patient needs service only a few minutes a day. For the...
Chapter
We present an exact solution approach to the constrained shortest path problem with a super additive objective function. This problem generalizes the resource constrained shortest path problem by considering a cost function c(·) such that, given two consecutive paths P1 and P2, c(P1 ∪ P2) ≥ c(P1) + c(P2). Since super additivity invalidates the Bell...
Article
Motivated by a challenging problem arising in wireless network design, we investigate a new nonlinear variant of the set covering problem with hyperbolic objective function. Each ground-set element (user) competes with all its neighbors (interfering users) for a shared resource (the network access time), and the goal is to maximize the sum of the r...
Article
Wireless local area networks (WLANs) are widely used for cable replacement and wireless Internet access. Because the medium access control (MAC) scheme of WLANs has a strong influence on network performance, it should be accounted for in WLAN design. This paper presents AP location models that optimize a network performance measure specifically for...
Conference Paper
We consider a one layer network design problem in the presence of Shared Risk Groups (SRGs).We can define an SRG as a set of links of the logical layer that simultaneously fail in the case of a failure of a lower layer.We propose a mathematical model for the dedicated protection and two alternative models for the shared protection, all based on flo...
Article
Full-text available
Wireless Mesh Networks (WMNs) can partially replace the wired backbone of traditional wireless access networks and, similarly, they require to carefully plan radio resource assignment in order to provide the same quality guarantees to traffic flows.In this paper we study the radio resource assignment optimization problem in Wireless Mesh Networks a...
Conference Paper
We present a class of problems that arise in the design of the Next Generation Access Networks. The main features of these networks are: to be based on fiber links of relatively long length with respect to traditional copper based networks, users may be reached directly by fibers, and the presence of few central offices managing a large number of u...
Article
Full-text available
We consider two approaches for solving the classical minimum vertex coloring problem, that is the problem of coloring the vertices of a graph so that adjacent vertices have different colors, minimizing the number of used colors, namely Constraint Programming and Column Generation. Constraint Programming is able to solve very efficiently many of the...
Article
Full-text available
This paper surveys recent applications and advances of the constraint programming-based column generation framework, where the master subproblem is solved by traditional OR techniques, while the pricing subproblem is solved by constraint programming (CP). This framework has been introduced to solve crew assignment problems, where complex regulatio...
Article
Full-text available
This article presents a column generation approach to a resource allocation problem arising in managing Wireless Mesh Networks. The problem consists in routing the given demands over the network and to allocate time resource to pairs of nodes. Half-duplex constraints are taken into account together with the aggregate interference due to simultaneou...
Article
Full-text available
Demand-adaptive transit systems (DAS) display features of both traditional fixed-line bus services and purely on-demand systems, that is, they offer demand- responsive services within the framework of traditional scheduled bus transportation. Similarly to most transportation systems dedicated to serve several demands with the same vehicle, demand-a...
Article
When piling a set of items in a single stack, one often does not pay attention to the order. Real-life experience suggests that, whenever a specific item is suddenly requested, we need to dig very deep into the stack to extract it.In this paper we investigate stack reordering strategies aiming at minimizing the number of pop and push operations. In...
Article
Full-text available
Radio planning and coverage optimization are critical issues for service providers and vendors that are deploying third generation mobile networks and need to control coverage as well as the huge costs involved. Due to the peculiarities of the Code Division Multiple Access (CDMA) scheme used in 3G cellular systems like UMTS and CDMA2000, network pl...
Article
Full-text available
In this paper novel optimization models are proposed for planning Wireless Mesh Networks (WMNs), where the objective is to minimize the network installation cost while providing full coverage to wireless mesh clients. Our mixed integer linear programming models allow to select the number and positions of mesh routers and access points, while accura...
Article
The possibility of adding multi-protocol label switching (MPLS) support to transport networks is considered an important opportunity by telecom carriers that want to add packet services and applications to their networks. However, the question that arises is whether it is suitable to have MPLS nodes just at the edge of the network to collect packet...
Article
The possibility of adding multi protocol label switching (MPLS) support to transport networks is considered an important opportunity by telecom carriers that want to add packet services and applications to their networks. However, the question arises whether it is suitable to have MPLS nodes just at the edge of the network to collect packet traffic...
Conference Paper
Full-text available
The classical approach of radio planning in wireless access networks is often tailored as a set covering problem. Such approach is no longer suited for Wireless Mesh Networks (WMNs), where, beside the problem of covering clients, also the wireless network topology must be planned and the tra-c must be routed on wireless links towards mesh access po...
Article
Although there is an extensive literature dealing with network design, little attention has been devoted to networks with complicated node costs. Although node costs, depending linearly on the total passing flow, can be easily embedded into the more usual framework of networks with link costs, when the node costs are, for instance, a stepwise funct...
Article
Full-text available
Radio planning and coverage optimization are critical issues when deploying and expanding third generation cellular systems. We investigate mixed integer programming models for locating and configuring base stations in UMTS networks so as to maximize cov- erage and minimize installation costs. The overall model considers both uplink and downlink di...
Article
Full-text available
As the demand for wireless service provisioning keeps increasing, new wireless tech-nologies are required to extend the coverage capabilities of classical wireless access net-works like WLANs, WMANs and cellular systems. In this field, Wireless Mesh Network-ing (WMN) seems to be the most promising solution. WMNs comprise three types of devices: mes...
Conference Paper
Full-text available
The possibility of adding MPLS support to transport networks is considered an important opportunity by telecom carriers that want to add packet services and applications to their networks. However, the question arises whether it is convenient to add MPLS nodes just at the edge of the network to collect packet traffic from users, or it is better to...
Chapter
Full-text available
During the last decade the tremendous success of mobile phone systems has triggered considerable technological advances as well as the investigation of mathematical models and optimization algorithms to support planning and management decisions. In this chapter, we give an overview of some of the most significant optimization problems arising in pl...
Article
In this paper we deal with the problem of partitioning the edge set of a bipartite graph G=(L∪R,E) with prescribed layout into the minimum number of non-crossing b-matchings. Some bounds and properties are discussed and an exact O(|E|loglogmin{|L|,|R|}) is presented for its solution.
Conference Paper
The impressive market spread of IEEE 802.11 based Wireless Local Area Networks (WLANs) is calling for quantitative approaches in the network planning procedure. It is common belief that such networks have the potentials to replace traditional indoor wired local networks and allow flexible access outdoor, eventually competing with classical cellular...
Article
The demand-adaptive systems studied in this paper attempt to offer demand-responsive services within the framework of traditional scheduled bus transportation: Users call to request service between two given points and, in so doing, induce detours in the vehicle routes; at the same time, though, a given set of compulsory stops is always served acco...
Article
Networks are physically and logically decomposed into layers with different technological features. Often, the routing of a demand through a non-multiplexing layer is made by grooming several demands at another, multiplexing-capable layer, thus using less capacity on the former but more on the latter. The problem of designing such a multi-layer net...
Conference Paper
In this paper we consider a particular pick-up and delivery vehicle routing problem, with unit vehicle capacity and possible compatibility constraints between consecutive operations. The problem arises in the collection and disposal of bulky recyclable waste, where containers of different types, used to collect different waste materials, must be pi...
Conference Paper
Full-text available
Wireless local area networks (WLANs) are spreading all over the planet with impressive speed and market penetration. They will replace traditional indoor wired local networks and allow flexible access outdoor, eventually competing with classical cellular systems (GSM, GPRS, UMTS, etc.) in the provision of wireless services. Although the small syste...
Conference Paper
Full-text available
Beam forming techniques of adaptive antenna arrays (smart antennas) allow to reduce the mutual interference of simultaneous transmission in wireless access systems exploiting angular separation of user terminals. At the radio resource management layer the information on the arrival direction of signals can be taken into account by the scheduling al...
Conference Paper
Full-text available
The impressive market spread of IEEE 802.11 based wireless local area networks (WLAN) calls for quantitative approaches in the network planning procedure. It is common belief that such networks have the potential to replace traditional indoor wired local networks and allow flexible access outdoors, eventually competing with classical cellular syste...