B-coloring is a problem in graph theory. It can model some real applications, as well as being used to enhance solution methods for the classical graph coloring problem. In turn, improved solutions for the classical c...
详细信息
B-coloring is a problem in graph theory. It can model some real applications, as well as being used to enhance solution methods for the classical graph coloring problem. In turn, improved solutions for the classical coloring problem would impact a larger pool of practical applications in several different fields such as scheduling, timetabling and telecommunications. Given a graph G = (V, E), the b-coloring problem aims to maximize the number of colors used while assigning a color to every vertex in V, preventing adjacent vertices from receiving the same color, with every color represented by a special vertex, called a b-vertex. A vertex can be a b-vertex only if the set of colors assigned to its adjacent vertices includes all the colors, apart from the one assigned to the vertex *** work employs methods based on linear programming to derive new upper and lower bounds for the problem. In particular, starting from a Mixed Integer linear programming model recently presented, upper bounds are obtained through partial linear relaxations of this model, while lower bounds are derived by considering different variations of the original model, modified to target a specific number of colors provided as input. The experimental campaign documented in the paper led to several improvements to the state-of-the-art results.(c) 2022 The Author(s). Published by Elsevier Ltd on behalf of Association of European Operational Research Societies (EURO). This is an open access article under the CC BY-NC-ND license (http://***/licenses/by-nc-nd/4.0/).
We propose a vector linear programming formulation for a non-stationary, finite-horizon Markov decision process with vector-valued rewards. Pareto efficient policies are shown to correspond to efficient solutions of t...
详细信息
This letter proposes a new power gain pattern synthesis-based (PGPS-based) algorithm for maximizing the minimum array power gain in a wide-beam mainlobe via linear programming. The existing PGPS-based algorithm has be...
详细信息
This letter proposes a new power gain pattern synthesis-based (PGPS-based) algorithm for maximizing the minimum array power gain in a wide-beam mainlobe via linear programming. The existing PGPS-based algorithm has been proved to outperform the existing shaped beam pattern synthesis based (SBPS-based) algorithms. However, its optimal solution to the PGPS problem can only be obtained via iterative procedures and its convergence cannot be theoretically guaranteed. One disadvantage of this nonconvergence is that the desired sidelobe level (SLL) might be unobtainable. This letter reformulates the original PGPS problem and transforms it into an approximately equal convex form. As a result, the convergence of the proposed algorithm is ensured and the desired SLL can always be obtained. Moreover, the proposed algorithm can accelerate the computational time. Its performance is assessed with HFSS simulated data by comparing it with the existing PGPS-based algorithm and the SBPS-based algorithms.
This study discusses the practicality of Realistic Mathematics Education based learning design of linear programming for financial accounting and major in Xth grade vocational high schools. The research method used is...
详细信息
Due to the increasing number of renewable energy sources (RES) and electric vehicles (EVs) in Germany and the resulting risk of overloading the electrical grid, the charging process of the EVs must be controlled and a...
详细信息
Due to the increasing number of renewable energy sources (RES) and electric vehicles (EVs) in Germany and the resulting risk of overloading the electrical grid, the charging process of the EVs must be controlled and adapted to the generation of the RES. Therefore, a charging control system based on the method of linear programming (LP) is proposed in this research. The aim is to charge several EVs to the desired state of charge (SoC) of the battery in the given time while maximizing the share of photovoltaic (PV) power generation during charging and reducing charging load peaks. In order to achieve the aim of the optimization, a PV forecast is used to predict the locally generated PV power. The results show that the charging control system in this paper is particularly suitable for EVs that have long parking time during the day, such as a typical working day. A single charging point with a power of 22 kW is sufficient to charge six EVs completely during working hours. The controlled charging of six EVs maximizes the PV share during charging and reduces charging load peaks.
The large-scale penetration of electric vehicles (EVs) into the power system will provoke new challenges needed to be handled by distribution system operators (DSOs). Demand response (DR) strategies play a key role in...
详细信息
The large-scale penetration of electric vehicles (EVs) into the power system will provoke new challenges needed to be handled by distribution system operators (DSOs). Demand response (DR) strategies play a key role in facilitating the integration of each new asset into the power system. With the aid of the smart grid paradigm, a day-ahead charging operation of large-scale penetration of EVs in different regions that include different aggregators and various EV parking lots (EVPLs) is propounded in this study. Moreover, the uncertainty of the related EV owners, such as the initial state-of-energy and the arrival time to the related EVPL, is taken into account. The stochasticity of PV generation is also investigated by using a scenario-based approach related to daily solar irradiation data. Last but not least, the operational flexibility is also taken into consideration by implementing peak load limitation (PLL) based DR strategies from the DSO point of view. To reveal the effectiveness of the devised scheduling model, it is performed under various case studies that have different levels of PLL, and for the cases with and without PV generation.
A plethora of program analysis and optimization techniques rely on linear programming at their heart. However, such techniques are often considered too slow for production use. While today's best solvers are optim...
详细信息
A plethora of program analysis and optimization techniques rely on linear programming at their heart. However, such techniques are often considered too slow for production use. While today's best solvers are optimized for complex problems with thousands of dimensions, linear programming, as used in compilers, is typically applied to small and seemingly trivial problems, but to many instances in a single compilation run. As a result, compilers do not benefit from decades of research on optimizing large-scale linear programming. We design a simplex solver targeted at compilers. A novel theory of transprecision computation applied from individual elements to full data-structures provides the computational foundation. By carefully combining it with optimized representations for small and sparse matrices and specialized small-coefficient algorithms, we (1) reduce memory traffic, (2) exploit wide vectors, and (3) use low-precision arithmetic units effectively. We evaluate our work by embedding our solver into a state-of-the-art integer set library and implement one essential operation, coalescing, on top of our transprecision solver. Our evaluation shows more than an order-of-magnitude speedup on the core simplex pivot operation and a mean speedup of 3.2x (vs. GMP) and 4.6x (vs. IMath) for the optimized coalescing operation. Our results demonstrate that our optimizations exploit the wide SIMD instructions of modern microarchitectures effectively. We expect our work to provide foundations for a future integer set library that uses transprecision arithmetic to accelerate compiler analyses.
While quantum weight enumerators establish some of the best upper bounds on the minimum distance of quantum error-correcting codes, these bounds are not optimized to quantify the performance of quantum codes under the...
详细信息
A separate case of a statement of the problem of the vector optimization, i.e., the problem of multipurpose linear programming (LP) is studied. Its formulation is presented as well as two the most common approaches to...
详细信息
作者：
Petráček, PetrVlk, BořivojŠvéda, Jiří
Department of Production Machines and Equipment Faculty of Mechanical Engineering Czech Technical University in Prague Czech Republic
This paper focuses on two aspects of feedrate optimization via linear programming methods. Namely, the effect of curve sampling on time optimality of the resultant feedrate profile and a method of feedrate profile ada...
详细信息
暂无评论