This letter presents a new expression of the chance constraint, representing ramping and operating reserve, in the context of the mixedintegerlinearprogramming (MILP) formulation for solving the hybrid stochastic/d...
详细信息
This letter presents a new expression of the chance constraint, representing ramping and operating reserve, in the context of the mixedintegerlinearprogramming (MILP) formulation for solving the hybrid stochastic/deterministic unit commitment (SDUC) problem. Based on projected disjunctive programming, the nonlinear chance constraint is converted into a set of linear constraints that has a more compact size. Numerical simulations highlight the primacy of the proposed MILP-SDUC reformulation as compared with other formulation approaches.
The integration of process planning and scheduling is important for an efficient utilisation of manufacturing resources. In general, there are two types of models for this problem. Although some MILP models have been ...
详细信息
The integration of process planning and scheduling is important for an efficient utilisation of manufacturing resources. In general, there are two types of models for this problem. Although some MILP models have been reported, most existing models belong to the first type and they cannot realise a true integration of process planning and scheduling. Especially, they are completely powerless to deal with the cases where jobs are expressed by network graphs because generating all the process plans from a network graph is difficult and inefficient. The network graph-specific models belong to the other type, and they have seldom been deliberated on. In this research, some novel MILP models for integrated process planning and scheduling in a job shop flexible manufacturing system are developed. By introducing some network graph-oriented constraints to accommodate different operation permutations, the proposed models are able to express and utilise flexibilities contained in network graphs, and hence have the power to solve network graph-based instances. The established models have been tested on typical test bed instances to verify their correctness. Computational results show that this research achieves the anticipant purpose: the proposed models are capable of solving network graph-based instances.
The paper provides a comparison between different control allocation techniques in over-actuated Autonomous Underwater Vehicles. The pseudoinverse, linearprogramming (LP), Quadratic programming (QP), mixedinteger Li...
详细信息
The paper provides a comparison between different control allocation techniques in over-actuated Autonomous Underwater Vehicles. The pseudoinverse, linearprogramming (LP), Quadratic programming (QP), mixedintegerlinearprogramming (MILP) and mixedinteger Quadratic programming (MIQP) are evaluated in simulation on the V-Fides vehicle model. The MILP and MIQP techniques allow to include in their implementations a more detailed characterization of the non-linear static behaviour of the actuators. This customizability can be also exploited to improve the practical stability of the system. The metrics used for comparison include the maximum attainable forces and torques, the integral of the error allocation and the required thrusters effort. Our simulation results show that, in particular with respect to thrusters effort, MILP and MIQP are the preferred allocation methods. The computational complexity associated to both methods is not such to compromise their implementation in operating vehicles;in particular, the MILP version is currently implemented in the V-Fides vehicle. (C) 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
An increasing number of applications in all aspects of society rely on data. Despite the long line of research in data cleaning and repairs, data correctness has been an elusive goal. Errors in the data, can be extrem...
详细信息
ISBN:
(纸本)9781450335317
An increasing number of applications in all aspects of society rely on data. Despite the long line of research in data cleaning and repairs, data correctness has been an elusive goal. Errors in the data, can be extremely disruptive, and are detrimental to the effectiveness and proper function of data-driven applications. Even when data, is cleaned, new errors can be introduced by applications and users who interact with the data. Subsequent valid updates can obscure these errors and propagate them through the dataset causing more discrepancies. Any discovered errors tend to be corrected superficially, on a case-by-case basis, further obscuring the true underlying cause, and snaking detection of the remaining errors harder. In this demo proposal, we outline the design of QFix, a query-centric framework that derives explanations and repairs for discrepancies in relational data based on potential errors in the queries that operated on the data. This is a marked departure from traditional data-centric techniques that directly fix the data. We then describe how users will use QFix in a demonstration scenario. Participants will be able to select from a number of transactional benchmarks, introduce errors into the queries that are executed, and compare the fixes to the queries proposed by QFix as well as existing alternative algorithms such as decision trees.
This paper presents a mixed-integer linear programming model to define the optimal operation of energy storage devices in radial distribution systems. The objective considered is the reduction of the energy purchase c...
详细信息
ISBN:
(纸本)9781509028757
This paper presents a mixed-integer linear programming model to define the optimal operation of energy storage devices in radial distribution systems. The objective considered is the reduction of the energy purchase cost from the distribution substation. The modeling of the energy storage devices determines both the charging and discharging periods, and the injected and extracted power. In addition, the number of daily charge/discharge cycles of the storage devices is limited to avoid an excessive reduction of their lifespan. The proposed model was used to analyze the influence of the location of energy storage devices in the operation of a system. The efficiency of the methodology was tested in several cases, using a 136-node distribution system.
To cover a large portion of annual electricity demand of an island with renewable power sources, battery capacity should be high because of temporal inconsistency between renewable power generation and power demand. B...
详细信息
ISBN:
(纸本)9781509033881
To cover a large portion of annual electricity demand of an island with renewable power sources, battery capacity should be high because of temporal inconsistency between renewable power generation and power demand. But such high battery capacity is practically infeasible because battery forms the greatest part of the cost of the renewable power system. As an alternative solution, wind turbines can he in idle state when overall renewable power generation is high, to reduce the required battery capacity. This paper investigates the optimal operational state scheduling of wind turbines for battery capacity reduction and its effect to reduction of renewable power generation and cost. A mixed-integer linear programming problem is formulated for the scheduling. A case study shows that the decrease of renewable power generation due to idle state of wind turbines is small, even if the battery capacity heroines significantly lower.
This paper presents a new methodology to security-constrained unit commitment (SCUC) problem with demand response resource (DRR) which is regarded as virtual power plant (VPP). In this paper, based on DRR bids informa...
详细信息
This paper presents a new methodology to security-constrained unit commitment (SCUC) problem with demand response resource (DRR) which is regarded as virtual power plant (VPP). In this paper, based on DRR bids information submitted to Korea Power Exchange (KPX), price elasticity and peak load are calculated and DRR cost function is obtained. The scheduling includes generator characteristics, DRR and reliability constraints Cost functions for generator and DRR are modeled as a piecewise linear function and an mixedintegerlinearprogramming (MILP) based method is applied to solve the optimization problem. Proposed methodology is tested and validated on The IEEE RTS-24 system. Through numerical simulation, DRR has demonstrated the decrease in the total operation cost as well as the curtailment of peak load. (c) 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
We present in this paper a general decomposition framework to solve exactly adjustable robust linear optimization problems subject to polytope uncertainty. Our approach is based on replacing the polytope by the set of...
详细信息
We present in this paper a general decomposition framework to solve exactly adjustable robust linear optimization problems subject to polytope uncertainty. Our approach is based on replacing the polytope by the set of its extreme points and generating the extreme points on the fly within row generation or column-and-row generation algorithms. The novelty of our approach lies in formulating the separation problem as a feasibility problem instead of a max-min problem as done in recent works. Applying the Farkas lemma, we can reformulate the separation problem as a bilinear program, which is then linearized to obtained a mixed-integer linear programming formulation. We compare the two algorithms on a robust telecommunications network design under demand uncertainty and budgeted uncertainty polytope. Our results show that the relative performance of the algorithms depend on whether the budget is integer or fractional.
This paper provides a novel self-scheduling model for price-taker generation companies (GENCOs) participating in a day-ahead energy market. Also, this paper models the effect of uncertainty of generating units' fo...
详细信息
ISBN:
(纸本)9781509041688
This paper provides a novel self-scheduling model for price-taker generation companies (GENCOs) participating in a day-ahead energy market. Also, this paper models the effect of uncertainty of generating units' forced outage considered by stochastic optimization approach in the self-scheduling. This approach allows the producer to maximize its profit while controlling the risk of profit variability. A scenario generation technique is considered to produce the scenarios for modeling the uncertainty source. Moreover, a well-known scenario reduction tool is applied to reduce the computational burden of the problem. A proposed methodology solves a set of stochastic mixed-integer linear programming (MILP) problems. The framework is effectively applied to a test system and the effect of GENCOs' unavailability and risk are obtained and discussed.
End-to-end flows, which have a set of chainlike subtasks, are widely used in distributed real-time systems. For instance, multimedia and automative applications require that subtasks finish executing on a chain of pro...
详细信息
ISBN:
(纸本)9781450347877
End-to-end flows, which have a set of chainlike subtasks, are widely used in distributed real-time systems. For instance, multimedia and automative applications require that subtasks finish executing on a chain of processors before their end-to-end deadlines. The scheduling of such chained subtasks decides the schedulability of a distributed real-time system. Since the subtask priority assignment problem is NP-hard in general, most heuristics are presented to schedule end-to-end flows in two separate steps. The first step calculates intermediate relative deadlines for frames, and the second step makes scheduling decisions under EDF scheduling. Because the quality of the priority assignment of subtasks will directly affect the schedulability of the distributed systems, the two separate steps may cause pessimism in schedulability analysis. To reduce potential pessimism, we combine the two steps in our novel dGMF-PA (distributed generalized multiframe tasks with parameter adaption) model. We present an algorithm based on mixed-integer linear programming for optimally selecting frame relative deadlines in the dGMF-PA model. An approximation algorithm is also proposed to reduce computational running time. Our approximation algorithm has a tunable speed-up factor of 1 + epsilon where epsilon can be arbitrarily small, with respect to the exact schedulability test of dGMF-PA tasks under EDF scheduling. Extensive experiments have shown that our approximation algorithm (which is a sufficient schedulability test) can schedule at most 44 % more than HOSPA, an existing state-of-the-art algorithm.
暂无评论