New Algorithm to Solve Mixed Integer Quadratically Constrained Quadratic Programming Problems Using Piecewise Linear Approximation

Techniques and methods of linear optimization underwent a significant improvement in the 20th century which led to the development of reliable mixed integer linear programming (MILP) solvers. It would be useful if these solvers could handle mixed integer nonlinear programming (MINLP) problems. Piecewise linear approximation (PLA) is one of most popular methods used to transform nonlinear problems into linear ones. This paper will introduce PLA with brief a background and literature review, followed by describing our contribution before presenting the results of computational experiments and our findings. The goals of this paper are (a) improving PLA models by using nonuniform domain partitioning, and (b) proposing an idea of applying PLA partially on MINLP problems, making them easier to handle. The computational experiments were done using quadratically constrained quadratic programming (QCQP) and MIQCQP and they showed that problems under PLA with nonuniform partition resulted in more accurate solutions and required less time compared to PLA with uniform partition.

PROFIT DISTRIBUTION IN IPD PROJECTS BASED ON WEIGHT FUZZY COOPERATIVE GAMES

Integrated Project Delivery (IPD) is regarded as an effective project delivery method that can deal with the challenge of the rapid development of the architecture, engineering, and construction (AEC) industry. In the IPD team, the alliance profit is not distributed fairly and effectively due to uncertainty, preventing the achievement of the IPD project goals. This study focuses on optimizing the profit distribution among stakeholders in IPD projects and uses quadratic programming models to solve fuzzy cooperative games in the IPD. A payoff function is used in the fuzzy alliance to determine the characteristics of the interval-valued fuzzy numbers, and different weights of the alliance and the efficiency of the player’s participation in the IPD are considered in the profit distribution. A case study is conducted, and the results of the proposed method are compared with those of crisp cooperative games. The results show that the fuzzy cooperative game increases the profit of participants in IPD projects. It is more practical to use weight fuzzy cooperative games than crisp games to express imputation. Moreover, the quadratic programming models and methods result in a fair and efficient profit distribution scheme in IPD projects.

Optimization-based transient control of turbofan engines: a sequential quadratic programming approach

Engine transient control has been challenging due to its stringent requirements from both performance and safety. Many methodologies have been proposed such as conventional schedule-based methods, linear parameter varying, multiobjective optimization and evolutionary computations etc. These approaches have been well-established and led to a series of significant results. However, they are either not providing limit protection or requiring exhaustive computational resources, particularly when generating results into full flight envelope applications. Consequently a compromise between limit protection and computational complexity is necessitated. This note considers a sequential quadratic programming (SQP)-based method for full flight envelope investigations. The proposed method can provide important design guidance and the corresponding claims are validated through detailed analysis and simulations.

Penerapan Harmony Search Algorithm untuk Menyelesaikan Economic Dispatch dengan Memperhitungkan Rugi-Rugi Transmisi

Penelitian ini bertujuan untuk menyelesaikan masalah Economic Dispatch (EC) menggunakan metode Artificial Intelligence (AI). Salah satu metode AI tersebut adalah Metode Harmony Search Algorithm (HSA). HSA ini merupakan suatu metode yang terinspirasi dari nada-nada musik yang di dengar. Simulasi HSA ini akan di implementasikan pada sistem 6 unit generator 425 MW yang ada di IEEE. Hasil simulasi menggunakan metode HSA dan metode Quadratic Programming (QP) dengan rugi-rugi transmisi adalah hasil metode HAS memperoleh biaya bahan bakar sebesar 24057,9070 $/h dan rugi-rugi transmisi sebesar 7,1246 MW. Sedangkan menggunakan metode QP memperoleh biaya bahan bakar sebesar 24059,4257 $/h dan rugi-rugi transmisi 7,1626 MW. Simulasi menggunakan metode HSA memperoleh biaya bahan bakar dan rugi rugi transmisi yang lebih kecil di bandingkan dengan menggunakan metode QP.