This paper describes the results of a pilot energy efficiency application, which is a part of the European project Esmartcity. The pilot refers to a real building of Politecnico di Milano composed of 14 classrooms over 4 floors. A quite complex centralized thermal network composed of different delivery devices (fan coils and radiators) and generation devices (water-to-water and air-to-water heat pumps, air handling unit with heat recovery) is used to control each room temperature, humidity and CO2levels. In spite of its complexity, the overall system is unable to sufficiently compensate disturbances, which are mainly due to people occupancy. The installation of smart multi sensors in a mesh network over the building allows data collection sufficient to build realistic physical models, design innovative and non-intrusive control strategies for disturbance compensations, and evaluate performance. In particular, the paper designs and compares an innovative rule-based feedback-feedforward control scheme integrating and estimation of people counting algorithms and a water temperature tracking algorithm based on a short recirculation circuit. Results show energy efficiency enforcement of about 12.6% and 10.7% respectively, without the need of structural retrofitting of the building and with a small, though measureable, comfort increase.

The paper addresses the problem to develop a reliable energy model of a building, to predict its future behavior and also to evaluate the impact of specific retrofitting actions. In particular, the problem is here addressed with the help of a real test case, namely a multi-storey residential building located in north of Italy. Four modeling approaches including purely data-driven (black-box), purely physics-based (white-box with EnergyPlus) starting from Building Information Modeling files, tuned white-box (tuned EnergyPlus) and hybrid model (gray-box) have been developed based on real sensor data (indoor and outdoor temperatures, solar radiation, energy consumption) and construction data. The paper discusses the main advantages and disadvantages of the various techniques in front of a real case, and provide suggestions on how to obtain a reasonable compromise between accuracy and amount of available data.

This paper addresses the problem of sharing a private Electrical energy Storage System (ESS) for thermoelectrical energy management in a group of buildings. Each building is equipped with an ESS which can be used partly or completely by other buildings in the same group. This sharing strategy creates coupling constraints among the controllers of each individual building. In this context, an increment proximal minimization method has been employed to manage the energy flows among the various ESS's through a distributed approach. The local controller of each building employs a Model Predictive Control (MPC) which focuses on balancing economic optimization and occupant comfort while fulfilling various local technical constraints. The proposed technique allows local controllers to operate with maximum autonomy and privacy since, at each iteration, a little amount of information is exchanged between each local controller to a centralized coordination unit. Indeed, only the information related to the coupling constraints is required to exchange with the centralized unit. The most significant advantage of the method is to allow the individual building to exploit effectively not only its own ESS but also any excess power and energy capacity of the ESSs of other buildings. The simulation results show the accuracy and efficiency of the proposed method.

This paper addresses the problem of thermal energy efficiency in domestic buildings. As opposed to classic optimal approach, a sensitivity analysis and comparison have been performed to evaluate both comfort and consumption of different heating scheduling, corresponding to different user-oriented scenarios, which allows to derive basic operating rules. Also continuous and discontinuous heating strategies are compared. The various scenarios are evaluated for different building thermal properties and different climatic conditions, under a classic mixed PID and hysteresis control scheme. The case study here considered is a house heated through a radiant floor system. A new index of assessment of user's comfort is also proposed. This paper explores the importance of heating scheme in terms of comfort and energy saving and highlights the importance of the decision maker point of view when deciding the most appropriate heating strategy. An optimal control strategy is also implemented (model-based predictive control) for comparison.

The dynamic model of thermal zones has nonlinear characteristics, large inertia and time variability. Dominating these difficulties in order to increase overall energy efficiency in buildings and improve the comfort level of building occupants is a controversial issue nowadays. Although there are several traditional, simple and effective control strategies such as thermostatic valves on radiators (TVR) or PID controllers to cope with these difficulties, some alternative solutions may be more efficient. In this study, the dynamic model of a single zone including hydronic system will be formulated according to the energy balance equation of the wall, pavement, zone and pipelines. This model can be easily extended to large thermal zones for instance for commercial buildings. Then, the suboptimal second order Sliding Mode Control (SMC) will be implemented on the simplified dynamic model. Besides, first order SMC will be analyzed for comparison and cross-validation of the suboptimal method. At the end the application of sliding mode approach will be analyzed for a radiant floor model including mixing valve and return water as an uncertainty resource. The main purpose of this study is to formulate a reliable dynamic model for thermal zones and make a cross-validation on the implemented first order SMC and suboptimal second order SMC.

Sensitivity analysis plays a vital role in building energy analysis. It is done to clarify which are the crucial variables affecting building thermal performance and to evaluate quantitatively those effects. It can be conducted both through energy simulation models and real case observations. The present paper is devoted to the description of the sensitivity analysis techniques that are able to extract the most effective parameters on the energy consumption of a commercial building, particularly medical centers. Energy consumption in medical centers, generally, depends on several parameters ranging from technical and geometrical aspects to climatic conditions. This paper is focused on the application of sensitivity analysis in term of energy consumption in medical centers through a benchmark simulation model which is developed by National Renewable Energy Laboratory (NREL) in order to classify the most effective parameters on energy consumption of a large hospitals.

This paper presents a model predictive control approach for the economic optimization of a microgrid including smart buildings, wind power production facilities and an energy storage unit. Various optimization scenarios are considered in a comprehensive and unified framework, which can be adapted to pursue different objectives at the same time, such as ensuring the electricity supply to the smart buildings, maximizing the profit from the electricity trading market, or managing the energy storage. The optimization problem can be addressed in a model predictive framework using the receding horizon approach, and ultimately formulated as a quadratic programming problem, which can be solved with reliable and efficient tools. In order to analyze a realistic scenario, the relevant data are taken from real systems (i.e., from a real wind farm and from a real commercial building, located in Italy). Simulation results show the economic advantages that can be gained through the combined usage of renewable energy generation and energy storage.

The paper describes an interesting combination of auto-tuning and adaptive scheduling approaches to design and update a feedback/feedforward control of the temperature in buildings.The focus here is on residential houses endowed with radiant floors, which are intrinsically complex to control due to large inertia and operational constraints, and on the disturbance rejection of the external temperature.Pure auto-tuning techniques may fail to converge if the initialization step is not done properly, due to the wide variety of possible buildings and compensation hard to adapt in closed loop.The proposed approach combines a classification of the typology of rooms based on physical parameters with auto-tuning, so that in a two-step closed-loop procedure, the room cluster can be quickly identified, and consequently the feedback controller and feedforward compensator be tuned.Numerical examples are provided to test the robustness of the proposed approach.

The present paper focuses on the development of a control system strategy on medium size industrial boilers (up to 1 MW) with the aim of having safe and efficient operation for the boiler itself.The class of the considered boiler is D-type water tube boiler.The basic plant model is based on Åström and Bell nonlinear dynamic model with simple adaptation due to specific geometries and physical constraints.The control system is mainly a combination of a pressure control loop and a three-element level controller.The pressure control loop here proposed consists of a gain scheduling PID control strategy to operate on heat power in order to keep the pressure at its desired value.The three-element level controller is a two-loop cascade control with feed forward water aimed at correcting the mismatch between the demand (steam flow) and feed water flow: level variation must be considered during this process because of the non-minimum phase behaviour of the level.Due to switching behaviour of gain scheduling approach, an adaptive control rule is also investigated in order to simplify the overall control structure and alleviate the adverse effects of the switching among many controllers in industrial applications.

The present paper addresses the design of an optimal online scheduler for a robotized packaging system. The task of the plant is to pick randomly incoming products from a conveyor belt which can never be stopped, and pack them into boxes with multiple capacity, with the goal to lose as less products as possible. Through a special mathematical representation, the control problem is formulated as a MILP optimization problem to be solved whenever a product is moved by a robot or enters the conveyor. The result is the assignment of products to robots and box places, which defines current and future missions for all the robots. In addition, the optimal scheduler decides also the speeds of the conveyors, to maximize the throughput. The proposed approach is independent of the layout (same belt directions, opposite belt directions, cross directions) and deals seamlessly with the steady state condition and transient behaviors. Numerical results confirm the superiority of the proposed approach with respect to the simpler solutions adopted in industrial applications.

The paper deals with the diagnostics of industrial automation devices and in particular with the real-time fault isolation. A diagnostic model-based method is proposed with the aim to isolate the occurrences of faults in automatic machinery simplifying the synthesis of the diagnostic models and the application of the developed technique to real cases. The theoretical foundation lays on the diagnoser automaton, which is suitably extended with time and with special modeling techniques that make it suitable for real-time execution rather than off-line test of the diagnosability. The model here adopted is called TiDiaM (Timed Diagnostic Model) for which automatic synthesis algorithms and a Java real-time executor (TiDE, Timed Diagnosis Executor) are proposed. The approach has been applied to a test case (the subsystem of an automatic machining centre called Pallet changer) in order to demonstrate its real-time applicability to an industrial example.

The work presented in this paper describes the concept of domain specific views (DSVs) according to which the specification of the control behavior is provided to the control developer. The basic idea is to investigate different application fields, to try to find common rules and models in different fields, and finally to build around this an automatic or semi-automatic transformation into executable code. The original idea is defined in a bigger aim that is the definition of a model oriented to the so-called ldquoautomation componentrdquo, used to standardize the design of an automation system. In the paper, the investigation is discussed for the discrete manufacturing and energy production fields, while in the main project (MEDEIA FP7-2007-211448) other fields are investigated and many languages and methodologies to develop control, diagnosis and simulation of automatic systems have been analyzed.

Energy saving is presently one of the main worldwide challenges. Energy savings can be obtained through energy efficiency increase in the management of energy devices, like heat pumps and co-generators, and with renewable sources. In this paper both actions are considered, in an integrated way, in order to pursue better savings. In particular, a building thermal system is analyzed. All the components, from generation up to consumption (e.g. radiant panels) are modeled and a control system is then developed and simulated. The first results show control effectiveness to achieve important energy savings and drive to search for advanced control techniques.

The aim of this paper is to describe a research roadmap for a multi-domain model-driven embedded systems design approach and the corresponding meta-model which is applicable to the domain of complex Industrial Automation and Control Systems (IACS). The special requirements of the industrial automation sector are taken into account by this novel approach, utilizing existing model-driven techniques. This approach is currently being developed in the Framework Seven (FP7) Embedded Systems Design project MEDEIA funded by the European Commission.

The paper deals with the problem of modeling and implementation of distributed automation systems for manufacturing applications. In particular, a novel approach has been conceived. A suitable meta-model of the production system has been derived, compliant with the state-of-the-art industrial standards. After the compilation and validation stages, an ontology is derived containing all the necessary definitions of modeling entities and constraints, to be used directly and explicitly in the execution of the control code. This entitles the control application to be defined as "model-driven" or better "ontology-driven". The results are obtained within the running EU project PABADIS'PROMISE(P2).

This paper addresses the dependability analysis of protection schemes of transmission grids using a computer simulator. Following modern protection schemes, a stochastic hybrid model has been developed in Modelica/Dymola environment. The model supports the evaluation of required dependability on the basis of suitable probability indices. A different simulation strategy has been implemented and its main features are discussed in detail. A logging tool has been created to supervise discrete events and assist in the results analyses. Furthermore, a custom simulation control panel helps to manage and to launch the simulation outside the Modelica environment.

A crucial step in the logic-control design for flexible manufacturing systems is the modeling of the desired behavior in terms of production sequences. These are typically expressed as a series of informal specifications which are to be translated into a formal model. The present paper introduces a Petri net-based methodology for the modeling of production sequences conceived as an incremental process, which progressively adds subnets to a partial model until all specifications have been included. A formal verification of the model is performed at every stage, so that specifications, which are incongruent with the current model and can jeopardize its correctness, can be detected and rejected or modified. No unnecessary modeling constraints are imposed on the model class and behaviors characterized by complex alternative-parallel relationships between operations can be represented. A specific algorithm is provided for the automatic synthesis of complex connection structures in the model, allowing for greater flexibility and complexity in the design process. Note to practitioners - Petri-net (PN) models can be effectively used in the development and validation of industrial logic-control systems as long as well-structured modeling techniques are available that can be easily automated in a computer-aided design environment. This paper introduces a structured and modular novel design methodology based on PNs, which constructs the logic-control model in an incremental fashion, taking progressively into account the user's product-flow specifications, in terms of composition constraints on the operation execution. Each step of the design process increases the model according to rules which guarantee that it holds specific well-definiteness properties. In particular, the methodology prevents possible design mistakes from leading to deadlocks. From a practical point of view, the design process fits the step-by-step specification method that is commonly adopted quite well, with the great advantage of having immediate feedback on the formal correctness of the model at each step. Also, given a suitable implementation in software packages, the interaction with the user does not require specific knowledge of PNs. The actual control logic can then be obtained by adding the resource model to the product-flow model and detailing operations.

Most applications in industrial automation could be hazardous for people, plant and environment. Therefore it is necessary for related distributed control systems, implementing safety functions for such applications, to rely on a real-time and fault tolerant communication among all connected stations. To realise this objective, safety related networks should be realised using Ethernet-based protocols with additional layers involved to fulfill safety requisites. The paper investigates the state of art technology of Ethernet-based safe communication systems with special attention to functional safety network requirements defined by the IEC 61508, pointing out the problems and examining how these communication protocols satisfy the defined requirements.

This paper discusses the design and the development of a control architecture for reconfigurable manufacturing systems. It presents the approach proposed by the PABADIS' PROMISE European research project which targets the issues of reconfigurability, flexibility, and efficiency in the context of the interaction among the three levels of the control pyramid (ERP, MES, Field). The key feature of the overall control architecture is a distributed organization based on agent technology and on a specific ontology for manufacturing systems.

The paper addresses the problem of modelling a FMS with random recipes and controlling it with an agent-based architecture. One of the features of the system are the random recipes, i.e. recipes that are unknown a priori for the control system, which represent a high flexible-routing class of FMS. In particular, a PN model able to represent both the mechanism of generation of random recipes and then the execution of such randomly generated recipe is shown. The obtained formal model is then studied to develop suitable control policies, e.g. against deadlocks. Then, such a model, is implemented in one of the most popular agent platforms, JADE (Java agent development framework)

The paper presents a modular control model to develop the control functions for manufacturing systems and its implementation using IEC 61499 function blocks. In particular, a new control module for automation objects is formally specified and its use on a hierarchical functional architecture has been discussed and the possible distribution of its IEC 61499 implementation is investigated. Finally, an application of such a model and its implementation for the development of the control functions for a laboratory plant emulating a general manufacturing system is shown

MOTIVATION: Many aging genes have been found from unbiased screens in model organisms. Genetic interventions promoting longevity are usually quantitative, while in many other biological fields (e.g. development) null mutations alone have been very informative. Therefore, in the case of aging the task is larger and the need for a more efficient genetic search strategy is especially strong. RESULTS: The topology of genetic and metabolic networks is organized according to a scale-free distribution, in which hubs with large numbers of links are present. We have developed a computational model of aging genes as the hubs of biological networks. The computational model shows that, after generalized damage, the function of a network with scale-free topology can be significantly restored by a limited intervention on the hubs. Analyses of data on aging genes and biological networks support the applicability of the model to biological aging. The model also might explain several of the properties of aging genes, including the high degree of conservation across different species. The model suggests that aging genes tend to have a higher number of connections and therefore supports a strategy, based on connectivity, for prioritizing what might otherwise be a random search for aging genes.

The paper addresses the problem of enumerating minimal siphons in an ordinary Petri net. The algorithms developed in this work recursively use a problem partitioning procedure to reduce the original search problem to multiple simpler search subproblems. Each subproblem has specific additional place constraints with respect to the original problem. Some results on algorithm correctness, convergence, and computational complexity are provided, as well as an experimental evaluation of performance. The algorithms can be applied to enumerate minimal, place-minimal siphons, or even siphons that are minimal with respect to given subsets of places.

In this paper we describe a totally new and original approach for combining global and local information in medical image processing. We implemented a virtual mobile robot and trained it using fuzzy neural networks to recognize segments of the myocardium while he navigates autonomously around the left ventricle (LV) of the heart. On its journey around the heart, the virtual exploring robot applies appropriate local edge detection to delineate fully automatically the borders of the myocardium. This may sound unconventional but it has proven effective enough to be integrated in a clinical analytical software tool.

This paper proposes a simple and effective way to represent shared resources in manufacturing systems within a Petri net model previously developed. Such a model relies on the bottom-up and modular approach to synthesis and analysis. The designer may define elementary tasks and then connect them with one another with three kinds of connections: self-loops, inhibitor arcs and simple synchronizations. A theoretical framework has been established for the analysis of liveness and reversibility of such models. The generalized synchronization, here formalized, represents an extension of the simple synchronization, allowing the merging of suitable subnets among elementary tasks. It is proved that under suitable, but not restrictive, hypotheses the generalized synchronization may be substituted for a simple one, thus being compatible with all the developed theoretical body.

When dealing with complex automation systems, the development and maintenance of control software often is a delicate task and takes a long time. The paper illustrates a Petri nets-based model to design logic controllers in an incremental mode, in which liveness analysis can be easily carried out, based on the compressed information contained in a compact graph that can be associated to the Petri net. Moreover, the incremental liveness analysis allows the portion of a net specifically involved in a fault to be identified and suggests a number of possible, even complex, remedies according to the nature of the detected faults. A necessary and sufficient condition of liveness is stated and proved.>

The paper faces the reachability and the reversibility problems in a class of Petri nets larger than other classes investigated for the same problems. The considered class of Petri net represents a formal language to design and analyze logic controllers. These nets may be decomposed in simple structures, called elementary control tasks, linked together through a limited number of connections, giving rise to arbitrarily complex nets. Such connections are the ones encountered in a typical logic control problem, as exchange of enabling signals (consensus/deny to control maneuvers) and the synchronous execution (shared resources modeling or shared operations). The purpose of the paper is to enlarge the set of theoretical tools previously developed for the incremental approach to the liveness analysis of a net, to be incorporated into a special CAD environment. In particular, the addressed topics are the choice of the initial marking and the analysis of reachability of nonlive markings.>

A conceptual and practical methodology is proposed for designing logic control systems with Petri nets. The main objectives are to reduce the design effort due to the complexity of control problems and to provide design criteria that perfectly fit the fundamental engineering approach to complexity, namely incremental design. The methodology is based on concepts coming from a number of theorems stated and proved. The designer is then provided with powerful basic net structures, implementing single control tasks, and with useful connections to coordinate and synchronize these tasks. This enables the designer to solve simple control problems and aggregate separate designs to form a more complex structure. Simple rules are provided that guarantee the preservation, after the merging of previous designs, of important net properties, like boundedness, cyclicness, and lifeness. To do so, it is sufficient to analyze an opportune graph based on the connections among tasks.>