The Traveling Salesman Problem Under Squared Euclidean Distances

Let $P$ be a set of points in $\mathbb{R}^d$, and let $\alpha \ge 1$ be a real number. We define the distance between two points $p,q\in P$ as $|pq|^{\alpha}$, where $|pq|$ denotes the standard Euclidean distance between $p$ and $q$. We denote the traveling salesman problem under this distance function by TSP($d,\alpha$). We design a 5-approximation algorithm for TSP(2,2) and generalize this result to obtain an approximation factor of $3^{\alpha-1}+\sqrt{6}^{\alpha}/3$ for $d=2$ and all $\alpha\ge2$. We also study the variant Rev-TSP of the problem where the traveling salesman is allowed to revisit points. We present a polynomial-time approximation scheme for Rev-TSP$(2,\alpha)$ with $\alpha\ge2$, and we show that Rev-TSP$(d, \alpha)$ is APX-hard if $d\ge3$ and $\alpha>1$. The APX-hardness proof carries over to TSP$(d, \alpha)$ for the same parameter ranges.Comment: 12 pages, 4 figures. (v2) Minor linguistic change

The Traveling Salesman Problem under squared Euclidean distances

Let P be a set of points in Rd, and let a = 1 be a real number. We define the distance between two points p, q ¿ P as |pq|a, where |pq| denotes the standard Euclidean distance between p and q. We denote the traveling salesman problem under this distance function by Tsp(d,a). We design a 5-approximation algorithm for Tsp(2,2) and generalize this result to obtain an approximation factor of 3a-1 +v6a/3 for d = 2 and all a = 2. We also study the variant Rev-Tsp of the problem where the traveling salesman is allowed to revisit points. We present a polynomial-time approximation scheme for Rev- Tsp(2, a) with a = 2, and we show that Rev-Tsp(d,a) is apx-hard if d = 3 and a > 1. The apx-hardness proof carries over to Tsp(d, a) for the same parameter ranges

The Traveling Salesman Problem under squared Euclidean distances

Let P be a set of points in Rd, and let a = 1 be a real number. We define the distance between two points p, q ¿ P as |pq|a, where |pq| denotes the standard Euclidean distance between p and q. We denote the traveling salesman problem under this distance function by Tsp(d,a). We design a 5-approximation algorithm for Tsp(2,2) and generalize this result to obtain an approximation factor of 3a-1 +v6a/3 for d = 2 and all a = 2. We also study the variant Rev-Tsp of the problem where the traveling salesman is allowed to revisit points. We present a polynomial-time approximation scheme for Rev- Tsp(2, a) with a = 2, and we show that Rev-Tsp(d,a) is apx-hard if d = 3 and a > 1. The apx-hardness proof carries over to Tsp(d, a) for the same parameter ranges

WORKPLACE HAPPINESS: ORGANIZATIONAL ROLE AND THE RELIABILITY OF SELF-REPORTING

Happier employees are more productive. Organizations across industry, no doubt, try to improve their employees’ happiness with the objective to achieve higher profitability and company value. While this issue has drawn increasing attention in high tech and other industries, little is known about the happiness of project management professionals. More research is needed to explore the current situation of workplace happiness of project management professionals and the driving factors behind it. This thesis explores the workplace happiness (subjective well-being) of project management professionals based on the exploratory statistical analysis of a survey 225 professionals in the state of Maryland, conducted in October 2014. The thesis applies Structural Equation Modeling and multiple regression analysis to the dataset and shows no significant impact of gender, age, work experience, and some other demographic traits on workplace happiness, also named well-being. Statistically significant factors for workplace happiness include: creating pleasant work environment, promoting open organization and well-managed team, and good organization to work for. With respect to the reliability of self-reporting, the study finds that the comprehensive appraisal tool designed by Happiness Works and New Economics Foundation can give a more reliable happiness evaluation. Two key factors, i.e. career perspectives and free to be self, can help alleviate the overconfidence of workplace happiness

Algoritmos de aproximação para problemas de alocação de instalações e outros problemas de cadeia de fornecimento

Orientadores: Flávio Keidi Miyazawa, Maxim SviridenkoTese (doutorado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: O resumo poderá ser visualizado no texto completo da tese digitalAbstract: The abstract is available with the full electronic documentDoutoradoCiência da ComputaçãoDoutor em Ciência da Computaçã