Towards the integration of system modelling with scenario planning to support strategy: the case of the UK energy industry

A key aspect of strategy is sense-making of the unfolding uncertainty in the business environment and responding appropriately to achieve organisational objectives. However, uncertainty means that there is more than one future open to an organisation. Sense-making is therefore problematic. Scenario planning is one approach to sense-making that helps to explore and understand uncertainty, aiming for the identification of potential predetermined elements in the business environment. In this paper we propose the integration of systems modelling with scenario planning to support the exploration of uncertainty, identify knowledge gaps that set a (subsequent) research agenda, understand the role and usefulness of historical data, and model research outcomes to help reveal potential predetermined elements. Specifically, scenario planning identifies potential predetermined elements in the business environment; system modelling in the form of behaviour-over-time graphs, causal mapping and feedback loops helps in structuring and linking variables and their interaction to provide an understanding of the systemic drivers of these predetermined elements. Methodological integration of this type enhances modellers’ ability to support strategy in organisations.     

Optimal preventive maintenance policy for electric power distribution systems based on the fuzzy AHP methods

In power distribution systems, with their great vastness and various outage causes, one of the most important problems of power distribution companies is to select a suitable maintenance strategy of system elements and method of financial planning for the maintenance of system elements with the two objectives of decrease in outage costs and improvement of system reliability. In this article, a practical method is introduced for the selection of a suitable system elements maintenance strategy; moreover, to plan the preventive maintenance budget for the system elements, two methods are offered: the cost optimization method and the fuzzy Analytic Hierarchy Process (AHP) method. In the former method, a new model of system maintenance cost is offered. This model, based on system outage information, the elements maintenance costs are determined as functions of system reliability indices and preventive maintenance budget. The latter method, too, a new guideline is introduced for considering the cost and reliability criteria in the trend of preventive maintenance budget planning. In this method, the preventive maintenance budget for the elements is determined based on relative priority of elements with reliability criteria. © 2015 Wiley Periodicals, Inc. Complexity 21: 70–88, 2016     

Energy policy modelling in developing and industrializing countries

A large number of models have been developed and used for energy policy planning, in a regional, national or international level, in order to cope with the broad variety of issues related to the energy problem. Energy models belong to the class of policy models, which address fuzzy and complex issues involving many non-quantitative factors, such as political issues, behavioural aspects, etc., as well as many uncertainties and lack of rigorous knowledge concerning the structure of the reference system, and the interrelationships of its elements. The role of energy policy models is very important, since they enhance understanding and communication, and they assist the policymakers to review plausible future configurations of relevant decision variables and parameters. In this paper one of the most important areas of energy modelling is investigated, that concerning the interactions between energy and economy in the group of Developing and Industrializing Countries (DIC's). It is pointed out that energy models used in the DIC's must capture the particular features of energy policy in these countries, such as rapid economic development fueled by expensive, depleting and often imported energy resources; dependence on foreign resources such as energy, capital, technology, etc.; management of indigenous resources, social structural changes, rapid population growth, urbanization and industrialization. In order to improve energy models and enhance their contributions in policy analysis, it is proposed that modelling efforts should be directed towards a better understanding of the energy-economy relationships in the DIC's, as well as towards the development of validated data bases.     

Mathematical modelling of hydraulic transients in simple systems

Efficiency and economy in the design and operation of a hydraulic system, as well as its safety, are objectives needing precise calculations of pressures and flowrates within the system. The calculations are typically very time-consuming and, depending on the characteristics of the system, very complicated and difficult to organize. A suitable mathematical modelling of the different ingredients in a hydraulic system is necessary to get useful results, which help fulfill those objectives. In this paper, the mathematical modelling used to develop a computer program to simulate hydraulic transients in a simple system is described. The program (DYAGATS), developed by the authors, is currently being used by organizations and consultancies to simulate and, consequently, analyze hydraulic transients in water systems. It makes use of the so-called elastic model, also known as waterhammer, to model the behavior of the fluid within the pipes. Also, lump models for the different elements that introduce, damp, modify, absorb, etc., perturbations in the systems are presented in a unified treatment. The main objective is to provide users with a powerful tool to devise the potential risks to which an installation may be exposed and to develop suitable protection strategies.     

Efficient algorithms for combined heat and power production planning under the deregulated electricity market

Combined heat and power (CHP) production is an important energy production technology that can yield much higher total energy efficiency than separate heat and power generation. In CHP production, the heat and power production follows a joint characteristic, which means that the production planning must be done in coordination. Cost-efficient operation of a CHP system can be planned by using an optimization model. A long-term planning model decomposes into thousands of hourly models. Earlier, in the regulated electric power market, the planning problem was symmetrically driven by heat and power demand. The liberalization of the power market has created an asymmetrical planning problem, where heat production responds to the demand and power production to the volatile market price. In this paper, we utilize this asymmetry to develop novel envelope-based dual algorithms for solving the hourly CHP models efficiently. The basic idea is to transform the three-dimensional characteristic operating region for heat and power production of each CHP plant into a two-dimensional envelope by taking the power price as a parameter. Then the envelopes of each plant are used for looking up the optimal solution rapidly. We propose two versions of the algorithm: the on-line envelope construction algorithm (ECON) where the envelopes are constructed for each hour based on the power price and the off-line envelope construction algorithm (ECOFF) where envelopes are pre-computed for all different power price ranges. We derive the theoretical time complexity of the two algorithms and compare their performance empirically with realistic test models against the ILOG CPLEX solver and the Power Simplex (PS) algorithm. PS is an extremely efficient specialized primal algorithm developed for the symmetrical CHP planning problem under the regulated market. On average, when reusing previous basic solutions, ECON is 603 times faster than CPLEX and 1.3 times faster than PS. ECOFF is 1860 times faster than CPLEX and four times faster than PS.     

Planning under uncertainty using parallel computing

Industry and government routinely solve deterministic mathematical programs for planning and schelduling purposes, some involving thousands of variables with a linear or non-linear objective and inequality constraints. The solutions obtained are often ignored because they do not properly hedge against future contingencies. It is relatively easy to reformulate models to include uncertainty. The bottleneck has been (and is) our capability to solve them. The time is now ripe for finding a way to do so. To this end, we describe in this paper how large-scale system methods for solving multi-staged systems, such as Bender's Decomposition, high-speed sampling or Monte Carlo simulation, and parallel processors can be combined to solve some important planning problems involving uncertainty. For example, parallel processors may make it possible to come to better grips with the fundamental problems of planning, scheduling, design, and control of complex systems such as the economy, an industrial enterprise, an energy system, a water-resource system, military models for planning-and-control, decisions about investment, innovation, employment, and health-delivery systems.     

Damped vibrations of the beam systems in rotational transportation

The major aim of this thesis is dynamical analysis of systems in rotational transportation with taking into consideration in the mathematical models the damping forces. The dissipation of energy in form of damping is inseparable connected with motion of analyzed systems. Up to now modelling of rod and beam systems in transportation was very often based on simplification and reduction of damping effect and on the other side the considerations very rarely apply to systems where the transportation effect was took into consideration. In this thesis the dynamical flexibility of the damped beam systems in transportation was presented. Analyzing systems were assumed as simple homogenous beam systems with symmetrical cross-section constant on whole length of the system. Most popular technical applications of such systems are put into use in propellers and sails of wind power plant, main, auxiliary rotors of helicopters, turbines, etc. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Bioenergy Systems Planning Using Location–Allocation and Landscape Ecology Design Principles

Rural energy planning is a nexus of sustainable development issues, particularly the sustainable utilization of biomass resources, on which rural parts of the developing world remain critically dependent. A landscape based rural bioenergy planning framework is presented, which is based on location–allocation and landscape ecology principles and considers both domestic and commercial energy demands and energy flows, as well as the landscape impact of the required bioenergy production zones. p-median modelling principles underly the location–allocation formulation. Optimized bioenergy landscape designs are presented, which illustrate both accessibility and landscape ecology objectives.     

Die Anwendung der gemischt-ganzzahligen linearen Optimierung zur Planung elektrischer Energieverteilnetze

Zusammenfassung Eine Analyse der Aufgabenstellungen und der Vorgangsweise bei der Planung elektrischer Energieverteilnetze zeigt Möglichkeiten für den Einsatz computerorientierter Berechnungsverfahren auf. Die wirtschaftlichen und technischen Zusammenhänge sowie Fragen der Lösbarkeit praktischer Planungsaufgaben führen zur Anwendung der gemischt-ganzzahligen linearen Optimierung. Die wichtigsten Komponenten der Zielfunktion sind die Investitions-, Verlust- und Ausfallkosten. Wesentliche Nebenbedingungen sind die thermische Belastbarkeit der Leitungen, die Lastflußbeziehungen, die Knotenspannungs- und Zuverlässigkeitsrestriktionen. Zur Lösung umfangreicher Aufgabenstellungen, wie sie in der Praxis auftreten, ist eine zweckmäßige Modellbildung von großer Bedeutung. Auf andere Anwendungsmöglichkeiten der gemischt-ganzzahligen linearen Optimierung im Bereich der Ausbau- und Betriebsplanung elektroenergetischer Systeme wird hingewiesen. Entscheidendes Kriterium für die praktische Anwendbarkeit dieser Planungsmethode ist der Modellumfang und damit der Lösungsaufwand. Zwei einfache Beispiele liefern dem Planer Anhaltspunkte für den praktischen Einsatz.

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Summary An analysis of planning processes in the area of power system planning reveals possibilities for computer application. The abilities to find useful solutions for problems of practical size, the economic and technical relations in distribution systems lead to linear mixed-integer models. The main components of the objective function are investment costs, costs of power losses and costs of energy not served. Essential technical restrictions are the thermal ratings of lines, load flow equations, nodal voltage and reliability restrictions. Sophisticated modelling techniques are necessary for extensive problems to restrict the model size. The applicability of linear mixedinteger models for other system extension or operating planning tasks is discussed. The main difficulty for widespread use is the expense to find solutions for models of practical size. Two examples show the application of the method for distribution network design.

     

Desenvolvimento de uma ferramenta computacional para a análise de elementos de membrana em concreto estrutural

Reinforced concrete elements subjected to membrane forces, i.e., elements subjected to in-plane shear and axial stresses are very common for modeling complex structures such as aircraft hangars, nuclear power plants, offshore oil platforms and long-span bridges. While the design of reinforcement for membrane elements is well adressed the same can not be said regarding the analysis of performance of these elements. Into this context, the present paper aims at providing a numerical tool developed in the Matlab platform, taking into account the “Modified Compression Field Theory”. In order to certificate the performance of the proposed tool, extensive numerical results were compared with experimental results available in the literature. The obtained results revealed that the proposed tool is very confident for the analysis of reinforced concrete membrane elements.     

Operational research in health services planning

Some of the characteristics which distinguish social planning from planning in the private sector, or in publicly owned industry, are identified. A survey of OR investigations (both tactical and strategic) in the area of health services planning supports the case that the mainstream OR contribution does violence to the nature of the system under study. In particular, problems are formulated in terms of (or transformed into) single objectives, to be optimized; aspects of the social world are subject to wholesale quantification, with resulting distortion; models make implausible data demands; project definition and execution reinforce the ‘scientisation’ of political debate; problems are formulated on the assumption of a single hierarchically powerful decision-maker; and problems are formulated as if they must be solved in toto at one point in time. It is suggested that we should look to the converse of these qualities for new directions in the application of operational research in social planning. Some examples are given of techniques and approaches, drawn both from within health services planning and from other areas, which exhibit these alternative characteristics.     

Identifying strategic action in highly politicized contexts using agent-based qualitative system dynamics

In the early phases of using system dynamics models to support strategic decision-making, the emphasis is on expressing information and physical flows. These aspects appropriately dominate those managed systems that can be thought of as being mechanistic. We suggest, however, that such an emphasis, to the exclusion of equally important system attributes such as power, leverage, influence and control, is inappropriate for a large class of problems involving agents and groups of agents in the system definition. Such politicized systems are ubiquitous, particularly in the strategic context, and in managing them it is necessary to take the political aspects of power into account at an early stage in the analysis. We present an approach to this class of problems, using a qualitative procedure based on influence diagrams. This method has been extensively and successfully used in consultancy to study the motivations and powers of agents and thereby produces naturally an output directed at action planning at the strategic level. While it is complementary to numerical system dynamics approaches, it is more successful in deriving components of strategic action directly from analysis.     

Stakeholder preference elicitation and modelling in multi-criteria decision analysis – A case study on urban water supply

Integration of multiple objectives to evaluate the alternative operating rules for urban water supply reservoir systems can be effectively accomplished by multi-criteria decision aid techniques, where preference elicitation and modelling plays an important role. This paper describes a preference elicitation and modelling procedure involving the multi-criteria outranking method PROMETHEE in evaluating these alternative operating rules. The Melbourne water supply system was considered as the case study. Eight performance measures (PMs) were identified under four main objectives to evaluate the system performance under alternative operating rules. Three major hypothetical stakeholder groups namely, resource managers, water users, and environmental interest groups were considered in decision-making. An interviewer-assisted questionnaire survey was used to derive the preference functions and weights of the PMs. The evaluation of alternative operating rules is not covered in this paper, rather an approach to elicit and model stakeholder preferences in decision-making is described.     

The Role of Discrete Event Simulation Techniques in Finite Capacity Scheduling

Discrete event simulation is becoming an established tool in finite capacity scheduling. However, recent work on scheduling systems has concentrated on the development of different modelling approaches and tools, without proper examination of how they can be used to meet business objectives. This paper examines the role of scheduling in improving business performance and suggests possible considerations in the development and implementation of a finite capacity scheduler. It reviews the advantages and limitations of discrete event simulation as a modelling technique for scheduling, and argues the need for further research to develop more versatile tools. A simulation-based scheduling system incorporating bottleneck planning principles to maintain throughput with low inventory is described, as are the experiences gained during its implementation in a medium-sized press shop.     

Robust placement and tuning of UPFC via a new multiobjective scheme‐based fuzzy theory

This article addresses a new modified honey bee mating optimization namely multiobjective honey bee mating optimization (MOIHBMO) based fuzzy multiobjective methodology for optimal locating and parameter setting of unified power flow controller (UPFC) in a power system for a long‐term period. One of the profits obtained by UPFC placement in a transmission network is the reduction in total generation cost due to its ability to change the power flow pattern in the network. Considering this potential, UPFC can be also used to remove or at least mitigate the congestion in transmission networks. The other issue in a power system is voltage violation which could even render the optimal power flow problem infeasible to be solved. Voltage violation could be also mitigated by proper application of UPFC in a transmission system. These objectives are considered simultaneously in a unified objective function for the proposed optimization algorithm. At first, these objectives are fuzzified and designed to be comparable against each other and then they are integrated and introduced to a MOIHBMO method to find the solution which maximizes the value of integrated objective function in a 3‐year planning horizon, considering the load growth. A power injection model is adopted for UPFC. Unlike, the most previous works in this field the parameters of UPFC are set for each load level to avoid inconvenient rejection of more optimal solutions. IEEE reliability test system is used as an illustrative example to show the effectiveness of the proposed method. © 2014 Wiley Periodicals, Inc. Complexity 21: 126–137, 2015     

Redundant objective functions in linear vector maximum problems and their determination

Suppose that in a multicriteria linear programming problem among the given objective functions there are some which can be deleted without influencing the set E of all efficient solutions. Such objectives are said to be redundant. Introducing systems of objective functions which realize their individual optimum in a single vertex of the polyhedron generated by the restriction set, the notion of relative or absolute redundant objectives is defined. A theory which describes properties of absolute and relative redundant objectives is developed. A method for determining all the relative and absolute redundant objectives, based on this theory, is given. Illustrative examples demonstrate the procedure.     

Efficient generation of alternative perspectives in public environmental policy formulation: applying co-evolutionary simulation–optimization to municipal solid waste management

In public policy formulation, it is generally preferable to create several quantifiably good alternatives that provide very different approaches to the particular situation. This is because public sector decision-making typically involves complex problems that are riddled with incompatible performance objectives and possess competing design requirements which are very difficult—if not impossible—to quantify and capture at the time supporting decision models are constructed. There are invariably unmodelled design issues, not apparent at the time of model construction, which can greatly impact the acceptability of the model’s solutions. Furthermore, public environmental policy formulation problems often contain considerable stochastic uncertainty and there are frequently numerous stakeholders with irreconcilable perspectives involved. Consequently, it is preferable to generate several alternatives that provide multiple, disparate perspectives to the problem. These alternatives should possess near-optimal objective measures with respect to the known modelled objective(s), but be fundamentally different from each other in terms of the system structures characterized by their decision variables. By generating a set of very different solutions, it is hoped that some of these dissimilar alternatives can provide very different perspectives that may serve to satisfy the unmodelled objectives. This study provides a co-evolutionary simulation–optimization modelling-to-generate-alternatives approach that can be used to efficiently create multiple solution alternatives that satisfy required system performance criteria in highly uncertain environments and yet are maximally different in their decision space. This new stochastic approach is very computationally efficient, since it permits the simultaneous generation of good solution alternatives in a single computational run of the SO algorithm. The efficacy and efficiency of this technique is specifically demonstrated using an earlier waste management case to enable direct comparisons to previous methods. Waste management systems provide an ideal setting for illustrating the modelling techniques used for such public environmental policy formulation, since they possess all of the prevalent incongruencies and system uncertainties inherent in complex planning processes.     

An Interactive,Graphical Approach to Linear Financial Models

Early attempts to utilize linear algebraic (L.P.) techniques in financial planning met with little success. This was probably due to a misunderstanding of the process by which financial and corporate plans were formulated. The planning process is now better understood and the use of computer-based models is well accepted. However current modelling systems perform only simple arithmetic evaluations. There is a prima facie case for re-examining linear algebraic methods to exploit the considerable amount of information which is available within a plan. This paper describes the work done in the South of Scotland Electricity Board to develop an interactive financial modelling system.     

Mechanical systems,equivalent in Lyapunov's sense to systems not containing non-conservative positional forces

Developing results obtained previously (Refs. Koshlyakov VN. Structural transformations of the equations of perturbed motion of a certain class of dynamical systems. Ukr Mat Zh 1997; 49 (4): 535–539; Koshlyakov VN. Structural transformations of dynamical systems with gyroscopic forces. Prikl Mat Mekh 1997; 61 (5): 774–780; Koshlyakov VN, Makarov VL. The theory of gyroscopic systems with non-conservative forces. Prikl Mat Mekh 2001; 65 (4): 698–704; Koshlyakov VN, Makarov VL. The stability of non-conservative systems with degenerate matrices of dissipative forces. Prikl Mat Mekh 2004; 68 (6): 906–913), the general problem of eliminating non-conservative positional structures from the second-order differential equation with constant matrix coefficients, obtained when modelling many mechanical systems, is considered. It is assumed that the matrices of the dissipative and non-conservative positional structures may, in particular, be degenerate. Under fairly general assumptions, theorems containing the necessary and sufficient conditions for a Lyapunov transformation to exist are proved. This converts the initial matrix equation to an equivalent autonomous form (in Lyapunov's sense) with a symmetrical matrix of the positional forces. An illustrative example is considered.     

Uncertainty in energy-economic modelling of the electrical power sector

The purpose of the present paper is to investigate what significance, if any, inclusion of uncertainties has for the conclusions of the modelling and analysis, i.e., whether the policy recommendations implicit in the results of the analysis depend on the inclusion or not of uncertainties. We do this within the context of a model of the Northern European electricity sector. The paper considers uncertainties about future states of nature. More specifically, we consider the inflow of water into a hydropower production system, where the states of nature are represented by a “dry”, a “normal” and a “wet” year. The problems may be formulated as non-linear optimisation models where the objective function basically consists of the expected value of the sum of consumers', producers', and authorities' surplus. The models take into account that there are losses in the transmission and distribution of electricity, and that the consumers pay an energy tax on their use of electricity. The consumers are divided into two groups, households and industry. Also, complementarity formulations are used, as these are shown to be more adequate for certain aspects, in particular where risk aversion within a liberalised market context is modelled. For each of eight Northern European countries, the basic results of the models are the installation of new production capacities, the production on old and new production capacities, the electricity prices, and the interchange between the countries. The investment in new production capacity is represented by a single value for each country, while the productions differ in that they depend on natural phenomena, which we refer to as the state of nature and represent by stochastic variables. It was found that in this context it was relatively easy to include stochastic elements in the model. Second, complementarity formulations are preferable to optimisation based modelling for some problem types. Third, results of the stochastic model have natural interpretations, also compared to one or several versions of a deterministic model. And fourth, we have seen that the quantitative results, and hence the implied policy recommendations, may differ significantly from those of deterministic models. We therefore conclude that increased attention should be given to the inclusion of stochastic elements into the modelling of energy systems. This revised version was published online in June 2006 with corrections to the Cover Date.