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作者： SAMAN AMINBAKHSH MIDDLE EAST TECHNICAL UNIVERSITY

学位级别：博士

Construction industry necessitates formulating impeccable plans by decision makers for securing optimal outcomes. Managers often face the challenge of compromising between diverse and usually conflicting objectives. Particularly, accurate decisions on the time and cost must be made in every construction project since project success is chiefly related to these objectives. This is realized by addressing the time-cost trade-off problem (TCTP) which is an optimization problem and its objective is to identify the set of time-cost alternatives that provide the optimal schedule(s). Due to discreteness of many resources in realistic projects, discrete version of this problem (DTCTP) is of great practical relevance. The Pareto front extension of DTCTP is a multi-objective optimization problem that facilities preference articulation of decision makers by providing them with a set of mutually non-dominated solutions of same quality. Due to the complex nature of DTCTP, the literature on large-scale problems is virtually void; besides, most of the existing methods do not suit actual practices and popular commercial planning software lack tools for solution of DTCTP. The main focus of this thesis relates to providing means for optimization of real- life-scale Pareto oriented DTCTPs and it aims to contribute to both researchers and practitioners by tightening the gap between the literature and the real-world requirements of the projects. The results of the comparative studies reveal that the proposed methods are successful for solving large-scale DTCTPs and provide the management with a quantitative basis for decisions on selection of the proper alternatives for the real-life-scale construction projects.

关键词： Discrete Time-Cost Trade-Off Problem Heuristic mixed-integer linear programming Pareto Front Particle Swarm Optimization

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Modeling Demand Propagation in Guaranteed Service Models

Modeling Demand Propagation in Guaranteed Service Models

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9th Vienna International Conference on Mathematical Modelling (MATHMOD)

作者： Loehnert, Madeleine Rambau, Joerg DATEV eG Nurnberg Germany Univ Bayreuth D-9540 Bayreuth Germany

In this paper, the class of guaranteed service models for multi-echelon inventory management is enhanced with explicit demand propagation. More specifically, the known mixed integer linear programming formulation for the guaranteed service model is refined by new variables and restrictions so that it describes the internal demand propagation exactly for linear demand bound functions. With this feature, aspects like outsourcing as well as decision dependent stochastic demands at internal stock points can be expressed exactly. The relevance of the new model is shown in an illustrative example, where the new model is able to find a solution with almost 40% lower actual cost compared to the existing approximative model without explicit demand propagation.

关键词： multi-echelon inventory management mixed-integer linear programming demand propagation outsourcing lost demand

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Filter Optimization for Real Time Digital Processing of Radiofrequency Signals: Application to Oscillator Metrology 72

Filter Optimization for Real Time Digital Processing of Radi...

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IEEE International Frequency Control Symposium (IFCS)

作者： Hugeat, A. Bernard, J. Goavec-Merou, G. Bourgeois, P. -Y. Friedt, J. -M. FEMTO ST Time & Frequency Dept Besancon France FEMTO ST Comp Sci Dept DISC Besancon France

ISBN: (纸本)9781538632147

Software Defined Radio (SDR) provides stability, flexibility and reconfigurability to radiofrequency signal processing. Applied to oscillator characterization in the context of ultrastable clocks, stringent filtering requirements are defined by spurious signal or noise rejection needs. Since real time radiofrequency processing must be performed in a Field Programmable Array to meet timing constraints, we investigate optimization strategies to design filters meeting rejection characteristics while limiting the hardware resources required and keeping timing constraints within the targeted measurement bandwidths.

关键词： Software Defined Radio mixed-integer linear programming Finite Impulse Response filter

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Hierarchical programming for Worst-Case Analysis of Power Grids 20

Hierarchical Programming for Worst-Case Analysis of Power Gr...

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Power Systems Computation Conference (PSCC)

作者： Djelassi, Hatim Mitsos, Alexander Fliscounakis, Stephane Panciatici, Patrick Rhein Westfal TH Aachen AVT Proc Syst Engn SVT Aachen Germany Reseau Transport Elect Versailles France

ISBN: (纸本)9781910963104

The aim of the present paper is to provide (n-1)-reliability to a power grid, guaranteeing nominal operation after the failure of any one out of n present grid components. Building on previous work (Fliscounakis et al., IEEE Transactions on Power Systems, 2013), a hierarchical programming problem is proposed to characterize the worst-case behavior of a power grid under a given contingency. The formulation is a mixed integer linear generalized semi-infinite program with a max-min program embedded. The different levels correspond to the choice of preventive actions, realization of uncertainties in the power supply and demand, and the choice of corrective actions. In order to model active components of the grid, models are proposed for load balancing and the behavior of phase-shifting transformers. Since no rigorous solution approaches are published for the problem at hand, the possibility of extending generalized semi infinite programming approaches to the present problem is discussed.

关键词： Hierarchical programming mixed-integer linear programming operation under uncertainty security-constrained optimal power flow worst-case analysis

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Scenario modelling and optimisation of renewable energy integration for the energy transition

Scenario modelling and optimisation of renewable energy inte...

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作者： Victor CODINA GIRONES ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE

学位级别：博士

A large number of countries have engaged themselves in an energy transition towards more re- newable energy in their energy systems. Motivations stem mainly from the need to reduce CO 2 emissions, and from a desire of their population to phase out technologies such as nuclear. Most of these countries promote biomass, wind and solar energy sources, among other possibilities. How- ever the current rate of deployment of renewable energy systems globally is not sufficient to reach the CO 2 emissions reduction that would allow to maintain the global average temperature increase below the 2 ° C threshold. The main barriers to a wider integration of renewable energy systems are i) their limited realisable potential, ii) their still limited competitiveness, iii) their intermittence; iv) public acceptance often related to poor level of energy literacy amongst citizens. Citizens are key decision-makers. They must decide on energy policies and on the energy technologies they use, hence they have the power to foster or halt the energy transition. This thesis presents two different strategies for addressing the problem of the integration of re- newable energy sources for energy transitions. The first one (Chapter 1) consists in developing an energy modelling tool to help decision-makers understand the energy system and find their own answers. The modelling approach also includes a new methodology for the calculation of the total cost of a national energy system. A model of the Swiss energy system has been created following this approach, which serves as basis to develop the Swiss-Energyscope online calculator. This calculator and its model present an optimal trade-off between scientific rigour and user-friendliness, which allows the reproduction of the energy transition scenarios conceived by the Swiss Government, and consequently its use for energy policy making. The second strategy (chapters 2 and 3) profits from the possibilities offered by mathematical mod- elling and optimi

关键词： Renewable energy renewable electricity energy transition energy scenarios energy planning en-ergy policy national energy systems energy modeling decision-making support energy calculator energy literacy optimization mixed-integer linear programming Switzerland woody biomass conversion biomass conversion pathways biofuels exergy

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Optimal Positioning of Mobile Emergency Resources for Resilient Restoration

Optimal Positioning of Mobile Emergency Resources for Resili...

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North American Power Symposium (NAPS)

作者： Poudel, Shiva Mukherjee, Monish Dubey, Anamika Washington State Univ Sch Elect Engn & Comp Sci Pullman WA 99164 USA

ISBN: (纸本)9781538671382

The extreme weather events have a significant impact on the aging and outdated power distribution infrastructures resulting in extended outages, the loss of critical services, and affecting customers' safety. This calls for ensuring a resilient operation by quickly restoring the critical services during natural disasters. Truck-mounted mobile emergency resources (MERs) are critical assets for fast electric service restoration across a distribution network, especially when customers do not have access to the main grid. This paper proposes a novel method for positioning and dispatching MERs to restore critical loads by dynamically forming restored networks or microgrids. A graph-theoretic approach is proposed to optimally locate MERs that maximally restores critical loads while simultaneously making the grid robust to post-restoration failures. The problem is modeled as a mixed-integer linear program that satisfies feeder's connectivity and operational constraints and assumes a radial operation in an open-loop distribution feeder with multiple tie-switches. Numerical simulations are performed to demonstrate the effectiveness of the proposed approach with the help of a multi-feeder test case with 7 tie-switches and 160 sectionalizing switches supplying 9 critical loads (CLs) using 4 MERs.

关键词： Distribution system restoration resilience mobile energy resources mixed-integer linear programming

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Security-Constrained Unit Commitment Considering Wind Generation Uncertainty

Security-Constrained Unit Commitment Considering Wind Genera...

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International Conference on Power System Technology (POWERCON)

作者： Zhai, Fang Shi, Li-Bao Ni, Yi-Xin Tsinghua Univ Grad Sch Shenzhen Shenzhen 518055 Peoples R China Natl Key Lab Power Syst Shenzhen Shenzhen 518055 Peoples R China

ISBN: (纸本)9781538664612

This paper presents a two-stage stochastic programming model for security-constrained unit commitment considering wind generation uncertainty and network security constraints. In this model, some possible scenarios are generated for describing wind generation uncertainty. Furthermore, a scenario reduction technology based on heuristic simultaneous backward reduction is applied to improve the computational efficiency. For the solution of this model, the linearization method is applied to transform this nonlinear optimization model into a deterministic and linear optimization model so that a mixed-integer linear program algorithm can be employed. Finally, numerical tests performed on a six-bus power system demonstrate the validity and effectiveness of the proposed model and optimization strategy.

关键词： Unit commitment wind power stochastic programming scenario analysis mixed-integer linear programming

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Retirement optimization through aircraft transfers and employment

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JOURNAL OF AIR TRANSPORT MANAGEMENT 2019年 79卷

作者： Newcamp, Jeffrey Verhagen, W. J. C. Santos, Bruno F. Curran, Richard Delft Univ Technol Fac Aerosp Kluyverweg 1 NL-2629 HS Delft Netherlands

Military aircraft retirements are an afterthought for many lifecycle planners. More active management of end-of-life fleets can yield increased confidence in fleet capability and retirement timelines. This work provides fleet managers with a tool to manage remaining aircraft flight hours to yield a desired fleet retirement pattern. It solves an equivalent flight hour minimization problem using a mixed-integer linear programming model for a military aircraft fleet having a network with basing and mission type constraints. The model minimizes differences in remaining equivalent flight hours for individual aircraft in future years, thereby allowing a fleet manager to alter the timeline for retirement of individual aircraft. A relocation cost is applied to discourage excessive, costly aircraft relocations. The United States Air Force A-10 Thunderbolt II aircraft is used as a case study while disruptions such as deployments are modeled to show the methodology's robustness. This work proves that a fleet of aircraft with dissimilar utilization histories and varying amounts of remaining useful lifetime can be actively managed to change the time at which individual aircraft are ready for retirement. The benefit to fleet managers is the ability to extract additional lifetime out of their aircraft prior to retirement.

关键词： Military aircraft Aircraft retirement mixed-integer linear programming Aircraft transfers

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BUSINESS ANALYSIS OF THE DRONE'S LAST MILE DELIVERY ENVIRONMENT

BUSINESS ANALYSIS OF THE DRONE'S LAST MILE DELIVERY ENVIRONM...

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作者： Caio Ferreira da Rosa Pantarotto POLITECNICO DI TORINO

学位级别：硕士

A good transportation from the last hub to the final customer receives the name of last mile delivery. Last mile is currently the least efficient component of the delivery chain, presenting high costs besides the small distances incurred. The major challenges of last mile delivery as it is today are related to an increase of labor costs and the wastes inherent to the current model of attended home delivery. In addition to that, customer requirements are getting more rigid as they expect not only precise and costless deliveries, but also fast ones. In that scenario, drone technology emerges as a potential problem solver. The introduction of drones performing the last mile delivery can improve its efficiency by increasing the asset usage, reducing the work force demanded and performing deliveries within a short lead time, among others. However, the introduction of this technology still faces some barriers, mainly related to its legalization, public acceptance and other issues related to the technology itself, such as its range and interaction with the final customer. In addition, the introduction of this technology does not only affect some operational components of the delivery chain, but also how the business entities within this environment perform their roles and interact with each other. Because of that, a study of the concept of business model and how it can be applied to the last mile delivery context was necessary. To develop suitable business models, a defined framework was used and a general classification of the drone usage potentialities on the specific context was made. As result, four business models involving different business entities, with the common factor that they all used the drone technology to perform the last mile delivery, were developed and analyzed, presenting not only how the actors interacted between each other but also the context in which each model could be applied. The four business models discusses were (i) centralized distribution c

关键词： last mile delivery drone technology business model mixed-integer linear programming

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Long-Term Co-optimized Generation and Transmission Expansion Planning with Renewables in Complicated Environments

Long-Term Co-optimized Generation and Transmission Expansion...

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2nd IEEE Conference on Energy Internet and Energy System Integration (EI2)

作者： Li Hui Liu Siwei Wu Lei Qi Qingru Zhang Mingli Shu Jun State Grid Econ Technol Res Inst Co Ltdr Beijing Peoples R China Clarkson Univ ECE Dept Potsdam NY USA Liaoning Elect Co Ltd Econ Tech Res Inst Shenyang Liaoning Peoples R China North China Elect Power Univ EE Dept Beijing Peoples R China

ISBN: (纸本)9781538685495

This paper presents a new approach for solving the multi-year co-optimized generation and transmission expansion planning problem with renewable energy resources in geographic information systems (GIS). The proposed optimization model is to determine when (which year), where (which cell), and what (which type) generators and transmission lines will be built for minimizing the sum of investment costs, operation costs (including energy and emission costs), and load shedding costs during the planning horizon. Prevailing constraints include power balance requirements, branch limits, power limits of generators, and construction limits of cells. A two-step approach to combine Dijkstra's algorithm and mixed-integer linear programming (MILP) is introduced for solving the large-scale optimization problem. The effectiveness of the proposed approach is validated by numerical case studies on a 9-bus system.

关键词： Long-term planning co-optimized generation and transmission expansion planning renewable generation planning optimal line routing geographic information systems Dijkstra's algorithm mixed-integer linear programming

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