Constraint qualification failure in action

This note presents a theoretical analysis of disjunctive constraints featuring unbounded variables. In this framework, classical modeling techniques, including big-M approaches, are not applicable. We introduce a lifted second-order cone formulation of such on/off constraints and discuss related constraint qualification issues. A solution is proposed to avoid solvers' failure.Financial support by grants: Digiteo Emergence ‘‘PASO’’, Digiteo Chair 2009-14D ‘‘RMNCCO’’, Digiteo Emergence 2009-55D ‘‘ARM’’ is gratefully acknowledged

Corel Painter Software as a Platform for the Production of Plastic Art paintings

Objectives: The study aims to: 1.Identify the technical possibilities offered by Corel Painter software for the visual artist in the production of paintings 2.Identify the most important technical processing features in Corel Painter software 3.Identify the aspects of artistic creativity implemented in Corel Painter software environment paintings. 4.Conducting an analytical & critical study for the artist works resulted from using Corel Painter program. Research hypotheses: The current research assumed that there is a significant relationship (zero or positive) between the use of Corel Painter software environment and paintings outputs for the artist using the program in the field of digital art. The research sample: The study was conducted on the Corel Painter program and the paintings that are the outputs of using this program as an illustration of the role to play in providing a platform for digital graphic simulating the traditional drawing Results: The current research found that there is a significant relationship (zero or positive) between the use of Corel Painter software environment and paintings outputs for the artist using the program in the field of digital art. also the research found that the disadvantages of digital art is that it often lacks the depth and texture, but that Corel painter program has dozens of drawing surfaces, and more to help in achieving more realistic results, Finally, the research concluded that Corel Painter is a program that is looking for a traditional artist to move into the world of digital painting, which allows the production of paintings the influence of graffiti, oil and watercolor and others enjoyed by the program Keywords: Corel Painter- Plastic Art- Digital Ar

Determinants Of The Voluntary Formation Of A Company Audit Committee: Evidence From Palestine

Drawing on agency theory, this paper investigates the determinants of voluntary audit committee (AC) formation among non-bank firms listed on the Palestine Stock Exchange (PSE). We used the annual reports of nearly all non-bank companies listed on the PSE as well as the company guides issued by the PSE for the period between 2010 and 2012. Logistic regression analysis was performed to identify the influence of a set of corporate governance mechanisms, ownership structures and company characteristics on the voluntary formation of ACs among non-bank Palestinian firms. The result of the analysis demonstrated that the AC is influenced by foreign ownership, institutional ownership, board diligence and external auditor type. This paper adds to the limited AC literature in Middle Eastern countries in general and in the Arab World in particular. This paper not only examines the determinants of the voluntary formation of ACs but also attempts to theorise about this formation

Does Corporate Governance Constrain Earnings Management in an Unstable Economic and Political Environment?

The purpose of this research is to examine the effects of corporate governance structures on earnings management behavior in a weakly governed and politically unstable environment. A panel of data from 35 non-bank companies listed on the Palestine Exchange between 2012 and 2019 was employed. A fixed effects regression model was used to examine the impact of certain board characteristics (board size, board meetings, and audit committee formation) and ownership structures (institutional ownership, foreign ownership, and ownership concentration) on earnings management in the volatile and risky political and economic environment of Palestine. The findings indicate that corporate governance and ownership systems in Palestine appear to be ineffective in constraining earnings management practices. None of the board attributes appear to constrain earnings management practices. However, there is weak evidence to show that ownership concentration has some effect in curbing earnings manipulation. The findings of this study are expected to increase awareness among Palestinian regulators, investors, and other policymakers regarding the role of boards of directors and institutional and foreign shareholders in monitoring Palestinian listed companies to enhance corporate governance and the quality of financial reporting

Convex Relaxations for Gas Expansion Planning

Expansion of natural gas networks is a critical process involving substantial capital expenditures with complex decision-support requirements. Given the non-convex nature of gas transmission constraints, global optimality and infeasibility guarantees can only be offered by global optimisation approaches. Unfortunately, state-of-the-art global optimisation solvers are unable to scale up to real-world size instances. In this study, we present a convex mixed-integer second-order cone relaxation for the gas expansion planning problem under steady-state conditions. The underlying model offers tight lower bounds with high computational efficiency. In addition, the optimal solution of the relaxation can often be used to derive high-quality solutions to the original problem, leading to provably tight optimality gaps and, in some cases, global optimal soluutions. The convex relaxation is based on a few key ideas, including the introduction of flux direction variables, exact McCormick relaxations, on/off constraints, and integer cuts. Numerical experiments are conducted on the traditional Belgian gas network, as well as other real larger networks. The results demonstrate both the accuracy and computational speed of the relaxation and its ability to produce high-quality solutions