论文标题
优越:寻求可行性和目标函数降低的不对称作用
Superiorization: The asymmetric roles of feasibility-seeking and objective function reduction
论文作者
论文摘要
可以将卓越的方法视为在寻求可行性和最小化最小化之间的概念上说明。它不是试图解决由建模约束和所选目标函数组成的全面约束最小化问题。相反,任务是找到一个可行的点,该点是“优越”(以明确的方式),相对于目标函数,仅通过寻求可行性的算法返回的目标函数。我们从电视上回顾了优越的方法以及今天的位置,并提出了对其的严格表述,但仅部分解决了保证问题。应用程序字段中的现实情况通常由建模过程定义的约束和数据(根据测量值获得或由模型用户决定)表示。寻求可行性的问题需要在所有约束的交集中找到一个点,而无需使用任何目标函数来针对任何特定的可行点。卓越方法的核心是建模者希望使用目标函数,这是限制因素,以寻求一种可行的解决方案,该解决方案将具有较低(不一定是最小)目标函数值的可行解决方案。这个目标比全面的约束最小化的要求少于寻求可行性的最小化,但要求更高。强调满足约束的需求,因为它们代表了现实世界的情况,人们认识到“寻求可行性和降低可行性的不对称作用”,即实现约束是主要任务,而降低了外在目标功能仅发挥二次作用。卓越方法论中有两个研究方向:弱优势和强大的优势。
The superiorization methodology can be thought of as lying conceptually between feasibility-seeking and constrained minimization. It is not trying to solve the full-fledged constrained minimization problem composed from the modeling constraints and the chosen objective function. Rather, the task is to find a feasible point which is "superior" (in a well-defined manner) with respect to the objective function, to one returned by a feasibility-seeking only algorithm. We telegraphically review the superiorization methodology and where it stands today and propose a rigorous formulation of its, yet only partially resolved, guarantee problem. The real-world situation in an application field is commonly represented by constraints defined by the modeling process and the data, obtained from measurements or otherwise dictated by the model-user. The feasibility-seeking problem requires to find a point in the intersection of all constraints without using any objective function to aim at any specific feasible point. At the heart of the superiorization methodology lies the modeler desire to use an objective function, that is exogenous to the constraints, in order to seek a feasible solution that will have lower (not necessarily minimal) objective function value. This aim is less demanding than full-fledged constrained minimization but more demanding than plain feasibility-seeking. Putting emphasis on the need to satisfy the constraints, because they represent the real-world situation, one recognizes the "asymmetric roles of feasibility-seeking and objective function reduction", namely, that fulfilling the constraints is the main task while reduction of the exogenous objective function plays only a secondary role. There are two research directions in the superiorization methodology: Weak superiorization and strong superiorization.