Adam Sędziwy

Advanced street lighting control

Design and control of outdoor lighting systems is a complex task, which is made even more difficult by introducing features like dynamic, sensor-based operation, multiple lighting levels and sophisticated, adjustable luminaires. This paper proposes an integrated approach, based on formal graph-based models and methods, to handle both of these tasks. The introduced formalisms help handle the state-space explosion related to the aforementioned characteristics. Control is performed by means of AI techniques (including rule-based systems and pattern matching), which is applied to the system using graph transformations. An illustrative, simple example is carried out throughout the paper, but the presented methods are highly scalable, which made them applicable to several practical projects of varying scale and characteristics.

A New Approach to Street Lighting Design

ABSTRACT This article compares two methods of roadway lighting design for situations compliant with EN 13201-2 ME/MEW series. The goal is to find out which one yields a more energy-efficient installation. The first method (further referred to as the “default” one), used by industry-standard software, assumes equally spaced luminaires (in any arrangement) and uniform width of the corresponding roadway. The second one (referred to as the “custom” one) operates on exact inventory data including spacing, road width, mounting height, and other parameters given per luminaire rather than set up globally. Both approaches are assumed to find solutions (installation setups) giving minimal energy consumption, which is accomplished, among others, by lamp dimming. The article presents the performed computations, discusses the obtained results, and analyzes the factors that might influence them. Results show that using the custom computation method and actual inventory data may bring an energy usage reduction at the level of 10% and more, compared to the default approach. Another issue critical from the practical point of view is the complexity of the solution-finding process. Although commonly known programs allow for building custom (nonuniform) scenes, the trial-and-error method of solution finding remarkably increases the design preparation time. Special heuristics embedded in the custom method allow avoiding the complexity issue and enable bulk processing, which is crucial in the case of large-scale computations made, for example, for large retrofits.

Parallel graph transformations supported by replicated complementary graphs

Graph transformations are the powerful formalism allowing describing a behavior of systems of various types. Parallel computations paradigm makes computations faster if we are able to reduce additional costs related to a communication overhead and a complexity of design of such systems. Replicated complementary graphs concept allows a parallel execution of graph transformation rules (designed for the centralized graph case) on a distributed environment. The possibility and the cost of data replication will be considered in the paper in the context of doublepushout approach.

Parallel graph transformations with double pushout grammars

Multiagent systems implementing artificial intelligence systems, require a formal representation to specify and simulate their properties and behavior. Double pushout graph grammars posses a very high expressive power; the possibility of the use of parallel graph transformations in a distributed environment make them useful in this area thanks to application of the complementary graphs concept. The mentioned idea is formally introduced and the polynomial computational complexity of underlying algorithms is proved.

Representation of Objects in Agent-Based Lighting Design Problem

Applying agent systems for solving large-scale design problems in particular in smart grid solutions, requires using proper representations at all levels of system description and specification. In the paper we introduce formally the hierarchical hypergraph representation of an urban space including both maps and physical objects like buildings. Such representation enables further decomposition of system model and performing parallel computations on it.

Solving Large-Scale Multipoint Lighting Design Problem Using Multi-Agent Environment

In the paper we focus on the problem of large-scale distribution of lighting points. Its solution is constrained by economic issues like power consumption or exploitation costs and, on the other side, by the computational complexity of design process. Multi-agent computational environment combined with graph and hypergraph representations of a problem allow meeting design requirements and objectives and, on the other hand, make the method applicable for large systems for which computational effectiveness is a crucial factor.

On the effective distribution and maintenance of knowledge represented by complementary graphs

Graph transformations are a powerful tool enabling the formal description of the behavior of software systems. In most cases, however, this tool fails due to its low efficiency. This can be overcome by introducing parallel graph transformations. The concept of complementary graphs enables two things: the decomposition of a centralized graph into many cooperating subgraphs, and their parallel transformations. Such a model is very useful in an agent environment, where subgraphs represent an individual knowledge of particular agents; this knowledge may be partially replicated and exchanged between the agents. The rules of a cooperation and an implicit synchronization of a knowledge, represented in this way, have been already defined in [10]. The second very important issue is the way of an initial graph distribution assuming the size criterion: the heuristic method proposed previously succeeds in 60% (i.e. 60% of subgraphs is consistent with the criterion). The method presented in this paper gives over 90% fit.

Labelled transition system generation from Alvis language

Alvis is a modelling language designed for the modelling and formal verification of embedded systems. The key concept of Alvis is an agent that denotes any distinguished part of a considered system with defined identity persisting in time. Alvis combines a graphical modelling of interconnections among agents with a high level programming language used for describing a behaviour of agents. The basic property of the Alvis Toolkit is the ability of generating of a formal system description directly from the Alvis source code. A way of generating Labelled Transition Systems for Alvis models is presented in the paper.

Application of distributed graph transformations to automated generation of control patterns for intelligent lighting systems

Abstract Designing a large infrastructure, such as a street lighting system, is a complex task itself especially in the context of Smart City and Smart Grid approaches. The problem is made even harder if it needs to be designed with control in mind. To facilitate a complex design process without losing fidelity, a graph-based formalism, namely General Environment Model (GEM), is proposed to be applied to model such an environment. Moreover, another graph-based model, namely Control Availability Graph or shortly CAG, is proposed to enable definition of routines for dynamic control of large-scale systems. Both of these models have been verified in practice, but the transition from GEM to CAG had been performed manually. In this paper, we propose a coherent, formal method of generating a control system from the graph-based environment description while taking into account the designers decisions. An application of the generated CAG as a control system yields up to 34% of energy consumption reduction in a pilot deployment of over 3500 light points for the city of Krakow, Poland.

Computational Support for Optimizing Street Lighting Design

The design of an urban area lighting has to preserve compliance with existing standards and regulations but also satisfy non-formalized rules related to the functionality, reliability or energy efficiency. The next important step following the design process is ensuring the optimal performance of a lighting system. It may be accomplished by a suitable system control. Such a formulation of a problem implies the high computational complexity of the design tasks. For that reason it’s necessary to develop an approach allowing to overcome the complexity problem. This article presents main factors determining the street lighting design and on the other side the formal methods providing an effective support in a design process.