Optimal Placement of Valves in a Water Distribution Network with CLP(FD)

This paper presents a new application of logic programming to a real-life problem in hydraulic engineering. The work is developed as a collaboration of computer scientists and hydraulic engineers, and applies Constraint Logic Programming to solve a hard combinatorial problem. This application deals with one aspect of the design of a water distribution network, i.e., the valve isolation system design. We take the formulation of the problem by Giustolisi and Savic (2008) and show how, thanks to constraint propagation, we can get better solutions than the best solution known in the literature for the Apulian distribution network. We believe that the area of the so-called hydroinformatics can benefit from the techniques developed in Constraint Logic Programming and possibly from other areas of logic programming, such as Answer Set Programming.Comment: Best paper award at the 27th International Conference on Logic Programming - ICLP 2011; Theory and Practice of Logic Programming, (ICLP'11) Special Issue, volume 11, issue 4-5, 201

LOGIC AND CONSTRAINT PROGRAMMING FOR COMPUTATIONAL SUSTAINABILITY

Computational Sustainability is an interdisciplinary field that aims to develop computational and mathematical models and methods for decision making concerning the management and allocation of resources in order to help solve environmental problems. This thesis deals with a broad spectrum of such problems (energy efficiency, water management, limiting greenhouse gas emissions and fuel consumption) giving a contribution towards their solution by means of Logic Programming (LP) and Constraint Programming (CP), declarative paradigms from Artificial Intelligence of proven solidity. The problems described in this thesis were proposed by experts of the respective domains and tested on the real data instances they provided. The results are encouraging and show the aptness of the chosen methodologies and approaches. The overall aim of this work is twofold: both to address real world problems in order to achieve practical results and to get, from the application of LP and CP technologies to complex scenarios, feedback and directions useful for their improvement

A Bilevel Mixed Integer Linear Programming Model for Valves Location in Water Distribution Systems

The positioning of valves on the pipes of a Water Distribution System (WDS) is a core decision in the design of the isolation system of a WDS. When closed, valves permit to isolate a small portion of the network, so called a sector, which can be de-watered for maintenance purposes at the cost of a supply disruption. However, valves have a cost so their number is limited, and their position must be chosen carefully in order to minimize the worst-case supply disruption which may occur during pipe maintenance. Supply disruption is usually measured as the undelivered user demand. When a sector is isolated by closing its boundary valves, other portions of the network may become disconnected from the reservoirs as a secondary effect, and experience supply disruption as well. This induced isolation must be taken into account when computing the undelivered demand induced by a sector isolation. While sector topology can be described in terms of graph partitioning, accounting for induced undelivered demand requires network flow modeling. The aim of the problem is to locate a given number of valves at the extremes of the network pipes so that the maximum supply disruption is minimized. We present a Bilevel Mixed Integer Linear Programming (MILP) model for this problem and show how to reduce it to a single level MILP by exploiting duality. Computational results on a real case study are presented, showing the effectiveness of the approach

Solving Real-Life Hydroinformatics Problems with Operations Research and Artificial Intelligence

Many real life problems in the hydraulic engineering literature can be modelled as constrained optimisation problems. Often, they are addressed in the literature through genetic algorithms, although other techniques have been proposed. In this thesis, we address two of these real life problems through a variety of techniques taken from the Artificial Intelligence and Operations Research areas, such as mixed-integer linear programming, logic programming, genetic algorithms and path relinking, together with hybridization amongst these technologies and with hydraulic simulators. For the first time, an Answer Set Programming formulation of hydroinformatics problems is proposed. The two real life problems addressed hereby are the optimisation of the response in case of contamination events, and the optimisation of the positioning of the isolation valves. The constraints of the former describe the feasible region of the Multiple Travelling Salesman Problem, while the objective function is computed by a hydraulic simulator. A simulation–optimisation approach based on Genetic Algorithms, mathematical programming, and Path Relinking, and a thorough experimental analysis are discussed hereby. The constraints of the latter problem describe a graph partitioning enriched with a maximum flow, and it is a new variant of the common graph partitioning. A new mathematical model plus a new formalization in logic programming are discussed in this work. In particular, the technologies adopted are mixed-integer linear programming and Answer Set Programming. Addressing these two real applications in hydraulic engineering as constrained optimisation problems has allowed for i) computing applicable solutions to the real case, ii) computing better solutions than the ones proposed in the hydraulic literature, iii) exploiting graph theory for modellization and solving purposes, iv) solving the problems by well suited technologies in Operations Research and Artificial Intelligence, and v) designing new integrated and hybrid architectures for a more effective solving

Constraint programming for optimal design of architectures for water distribution tanks and reservoirs: a case study

Sustav za raspodjelu vode je bitna komponenta svakog gradskog infrastrukturnog sustava. Njegov je projekt uglavnom težak zadatak zbog postojanja nekoliko složenih međusobno povezanih parametara. Između ostalih, neki parametri koji se moraju proučiti su potražnja za vodom, potrebni tlak, topografija, lokacija resursa, pouzdanost sustava, i korištenje energije. U ovom smo radu usmjereni na postojeći slučaj sustava za distribuciju vode s ciljem smanjenja troškova instaliranja zadovoljavanjem zahtjeva toga sustava. Problem rješavamo primjenom najnovijih metoda Programiranja Ograničenja kombiniranih s Analizom Intervala u svrhu preciznog baratanja s trajnim varijablama odluka. Eksperimentalni rezultati pokazuju da je predloženi pristup izvediv i globalni optimum postignut u svim slučajevima i u zadovoljavajućem vremenu.A water distribution system is an essential component of any urban infrastructure system. Its design is commonly a hard task mainly due to the presence of several complex interrelated parameters. Among others, some parameters to study are the water demand, pressure requirements, topography, location of resources, system reliability, and energy uses. In this paper, we focus on a real case of water distribution system in order to minimize installation costs by satisfying the given system requirements. We solve the problem by using state-of-the-art Constraint Programming techniques combined with Interval Analysis for rigorously handling continuous decision variables. Experimental results demonstrate the feasibility of the proposed approach, where the global optimum is reached in all instances and in reasonable runtime

CONSTRAINT PROGRAMMING FOR OPTIMAL DESIGN OF ARCHITECTURES FOR WATER DISTRIBUTION TANKS AND RESERVOIRS: A CASE STUDY

Original scientific paper A water distribution system is an essential component of any urban infrastructure system. Its design is commonly a hard task mainly due to the presence of several complex interrelated parameters. Among others, some parameters to study are the water demand, pressure requirements, topography, location of resources, system reliability, and energy uses. In this paper, we focus on a real case of water distribution system in order to minimize installation costs by satisfying the given system requirements. We solve the problem by using state-of-the-art Constraint Programming techniques combined with Interval Analysis for rigorously handling continuous decision variables. Experimental results demonstrate the feasibility of the proposed approach, where the global optimum is reached in all instances and in reasonable runtime. Keywords: constraint programming, optimization, water distribution Programiranje ograničenja za optimalni projekt arhitekture spremišta i rezervoara za distribuciju vode: analiza slučaja Izvorni znanstveni članak Sustav za raspodjelu vode je bitna komponenta svakog gradskog infrastrukturnog sustava. Njegov je projekt uglavnom težak zadatak zbog postojanja nekoliko složenih međusobno povezanih parametara. Između ostalih, neki parametri koji se moraju proučiti su potražnja za vodom, potrebni tlak, topografija, lokacija resursa, pouzdanost sustava, i korištenje energije. U ovom smo radu usmjereni na postojeći slučaj sustava za distribuciju vode s ciljem smanjenja troškova instaliranja zadovoljavanjem zahtjeva toga sustava. Problem rješavamo primjenom najnovijih metoda Programiranja Ograničenja kombiniranih s Analizom Intervala u svrhu preciznog baratanja s trajnim varijablama odluka. Eksperimentalni rezultati pokazuju da je predloženi pristup izvediv i globalni optimum postignut u svim slučajevima i u zadovoljavajućem vremenu

Infective Endocarditis: Inflammatory Response, Genetic Susceptibility, Oxidative Stress, and Multiple Organ Failure

Infective endocarditis is defined by a focus of infection within the heart. Despite the optimal care, the mortality approaches 30% at 1 year, so the care for this type of patients represents a challenge to improve the result in your care. The challenges in this clinical entity have several aspects such as the diversity of germs that cause endocarditis, and the most important epidemiologically has generated resistance to antimicrobial treatment along with the possibility of apoptosis in their host-germ interaction. The immunogenetic susceptibility to host infection is discussed, which represents a deep area of research. Inflammation, local and systemic, is complex, with the genesis of reactive oxygen species, which are harmful when the antioxidant defenses are exceeded, causing the break in the mitochondrial electron transport chain with the fall in energy genesis, multiple organ failure, and death. Both at the cellular level and in the mitochondria, possible therapeutic targets are also commented

Advancing Urban Flood Resilience With Smart Water Infrastructure

Advances in wireless communications and low-power electronics are enabling a new generation of smart water systems that will employ real-time sensing and control to solve our most pressing water challenges. In a future characterized by these systems, networks of sensors will detect and communicate flood events at the neighborhood scale to improve disaster response. Meanwhile, wirelessly-controlled valves and pumps will coordinate reservoir releases to halt combined sewer overflows and restore water quality in urban streams. While these technologies promise to transform the field of water resources engineering, considerable knowledge gaps remain with regards to how smart water systems should be designed and operated. This dissertation presents foundational work towards building the smart water systems of the future, with a particular focus on applications to urban flooding. First, I introduce a first-of-its-kind embedded platform for real-time sensing and control of stormwater systems that will enable emergency managers to detect and respond to urban flood events in real-time. Next, I introduce new methods for hydrologic data assimilation that will enable real-time geolocation of floods and water quality hazards. Finally, I present theoretical contributions to the problem of controller placement in hydraulic networks that will help guide the design of future decentralized flood control systems. Taken together, these contributions pave the way for adaptive stormwater infrastructure that will mitigate the impacts of urban flooding through real-time response.PHDCivil EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/163144/1/mdbartos_1.pd