Matching random colored points with rectangles

Let S ¿ [0, 1]2 be a set of n points, randomly and uniformly selected. Let R ¿ B be a random partition, or coloring, of S in which each point of S is included in R uniformly at random with probability 1/2. We study the random number M(n) of points of S that are covered by the rectangles of a maximum strong matching of S with axis-aligned rectangles. The matching consists of closed rectangles that cover exactly two points of S of the same color. A matching is strong if all its rectangles are pairwise disjoint. We prove that almost surely M(n) = 0.83 n for n large enough. Our approach is based on modeling a deterministic greedy matching algorithm, that runs over the random point set, as a Markov chain.Postprint (published version

Perceived Stress and Self-efficacy as Correlates of Satisfaction With the Dissertation Process Among Doctoral Students in Educational Psychology in Selected Universities in the United States

Purpose of the Study The purpose of this study is to investigate the role of perceived stress and self efficacy on student satisfaction with the dissertation process among doctoral students in educational psychology in selected universities in the United States. Method Survey research method was used as the research platform for this study. Online surveys using Survey Monkey were administered to doctoral student in Educational Psychology from selected universities in the United States. Dissertation self-efficacy was measured with the Dissertation Self-Efficacy Scale (DSES; Varney, 2003). Perceived Stress was measured with the Perceived Stress Scale-10 (PSS-10; Cohen, Kamarch & Mermelstein, 1983). Student satisfaction was measured by a single, straight forward question on how satisfied doctoral candidates and recent graduates were with the dissertation process. Descriptive statistics analysis was performed by frequency, mean and standard deviation to find out how satisfied were doctoral students in educational psychology with the dissertation process. Independent samples T-test were used to test significant gender differences in the satisfaction with the dissertation process. Finally, multiple regression analysis was conducted to analyze the correlations between perceived stress, self-efficacy and satisfaction with the dissertation process. Results Results indicated that participants in this study reported moderate levels of satisfaction with the dissertation process. The independent-samples t-test indicated no gender differences in student satisfaction with the dissertation process. Descriptive statistics and multiple regression analysis indicated that both perceived stress and self efficacy are positively and significantly correlated with satisfaction, suggesting that those with high levels of self-efficacy and moderate levels of perceived stress tend to be more satisfied with the dissertation process. Also, regression analysis indicated that the two predictor model accounts for 28% of the variance in satisfaction with the dissertation process. Conclusions In summary, high levels of dissertation self-efficacy and moderate or optimal levels of stress, influence satisfaction with the dissertation process and could enhance program completion of educational psychology doctoral students. Both students and institutions should focus on increasing doctoral candidates’ dissertation self-efficacy, maintaining moderate or optimal levels of stress and reducing high stress when necessary, and also on increasing student satisfaction with the dissertation process by maintaining program quality and encouraging positive and supportive student-advisor relationships

Self-efficacy, Locus of Control, Perceived Stress and Student Satisfaction as Correlates of Dissertation Completion

Purpose of the Study Doctoral students face a multitude of challenges in the process of completing their degree, and barriers to the success of doctoral program completion can occur at many different levels. Many factors contribute to dissertation completion or non-completion. Studying the influence of these factors on the task of dissertation completion may result in enhancing dissertation progress and program completion. The purpose of this study is to investigate the role of self-efficacy, locus of control, perceived stress and student satisfaction on dissertation completion among doctoral students in educational psychology at selected university in the United States. Method Survey research method was used as the research platform for this study. Online surveys using Survey Monkey were administered to doctoral student in Educational Psychology from selected universities in the United States. Dissertation self-efficacy was measured with the Dissertation Self-Efficacy Scale (DSES; Varney, 2003). Locus of control was measured with the Responsibility Scale (RS; Kluever & Green, 1998). Perceived Stress was measured with the Perceived Stress Scale (PSS; Cohen, Kamarch & Mermelstein, 1983). Student Satisfaction was measured by a single, straight forward question on how satisfied doctoral candidates and recent graduates were with the dissertation process. Path analysis was used to test the validity of a conceptualized model inter-relating participants’ self-efficacy, locus of control, perceived stress, satisfaction and dissertation/program completion. Results Results indicate that participants in this study reported high levels of self-efficacy, low levels of shared responsibility suggesting that participants believe that students rather than the institution should be in control for tasks associated with dissertation progress; and moderate levels of perceived stress and satisfaction with the dissertation process. Also, the model developed to study the relationships and interrelations between the variables explained 17% of the variance in dissertation progress/completion, primarily by the direct effects of self-efficacy, perceived stress and student satisfaction, and indirectly by locus of control. The model suggested that doctoral candidates are more likely to make progress on their dissertation and complete their programs if they report high selfefficacy and greater satisfaction with the dissertation process, and if they report low levels of institutional responsibility versus personal responsibility, and low or optimal levels of stress. High levels of stress appear to decrease both self-efficacy and satisfaction with the dissertation process. Conclusions An important finding of this study is the direct positive relationship between selfefficacy and student satisfaction with dissertation progress/completion, with self-efficacy being the most important predictor of dissertation completion followed by student satisfaction with the dissertation process. The more doctoral students believe in their ability to complete their dissertations and the more satisfied they are with the dissertation process, the more progress they make and the more likely they are to complete their doctoral program. In summary, high levels of dissertation self-efficacy, low levels of shared responsibility, moderate or optimal levels of stress, and moderate levels of student satisfaction with the dissertation process could enhance program completion of educational psychology doctoral students. Both students and institutions should focus on increasing doctoral candidates’ dissertation self-efficacy, establishing who is responsible for each task involved in the dissertation process, maintaining moderate or optimal levels of stress and reducing high stress when necessary, and also on increasing student satisfaction with the dissertation process by maintaining program quality and encouraging positive and supportive student - advisor relationships

The absorption of UE funds in the current context of the cohesion policy

Romania continues to be affected by the global recession. It has suffered a significant reduction in foreign investment since the start of the recession, as investors have moved away from emerging markets in search for security. Developing an appropriate, focused strategy for the allocation of EU funds is only the first, though perhaps the most important step in implementing the EU cohesion policy. The successful implementation of EU co-funded projects is contingent not only upon the effectiveness of these countries’ administrative systems, but also on the activity of the potential beneficiaries

Experimental results regarding the influence of initial ovality on local buckling under external pressure (collapse) of oil industry tubulars

An important load which can considerably affect the resistance capacity of oil industry tubulars (mainly casing and tubing in high pressure wells, and submarine pipelines installed in deep waters) is the external pressure, causing the pipe collapse phenomenon. Some of the factors with the greatest influence on pipe collapse behaviour are its geometrical imperfections (ovality, eccentricity, etc.). This paper presents the results of research activities aimed to investigate the influence of the pipe initial ovality on the external pressure collapse phenomenon, in order to define design methodologies and criteria for assessing the external pressure resistance capacity of oil industry tubulars. To that purpose, some tests have been performed on small scale pipe specimens, based on the similitude law, and their results have been compared with the calculation formulas usually used to assess pipe collapse resistance capacity considering the influence of initial ovality. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/1090

Analysis of the residual stress level in casing and its influence on the collapse strength

The collapse resistance of casing is influenced by many factors, among which the level of residual stresses is an essential one. This paper presents the results of research activities aimed to determine such stress level in seamless tube specimens made of grade N80 steel. These activities included: the selection – based on experimental and theoretical studies – of the most adequate method to determine the residual circumferential stresses in tubes for well casing; a series of experimental tests to define the level of such residual stresses and its variation across the tube thickness; finally, an evaluation of the influence of such stresses upon the value of the collapse pressure of casing. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/1156

Kosterlitz-Thouless scaling at many-body localization phase transitions

We propose a scaling theory for the many-body localization (MBL) phase transition in one dimension, building on the idea that it proceeds via a 'quantum avalanche'. We argue that the critical properties can be captured at a coarse-grained level by a Kosterlitz-Thouless (KT) renormalization group (RG) flow. On phenomenological grounds, we identify the scaling variables as the density of thermal regions and the lengthscale that controls the decay of typical matrix elements. Within this KT picture, the MBL phase is a line of fixed points that terminates at the delocalization transition. We discuss two possible scenarios distinguished by the distribution of rare, fractal thermal inclusions within the MBL phase. In the first scenario, these regions have a stretched exponential distribution in the MBL phase. In the second scenario, the near-critical MBL phase hosts rare thermal regions that are power-law distributed in size. This points to the existence of a second transition within the MBL phase, at which these power-laws change to the stretched exponential form expected at strong disorder. We numerically simulate two different phenomenological RGs previously proposed to describe the MBL transition. Both RGs display a universal power-law length distribution of thermal regions at the transition with a critical exponent $\alpha_c=2$, and continuously varying exponents in the MBL phase consistent with the KT picture.Comment: 17 pages, 10 figures; v3. minor changes, as published; v2. added section and appendix with new numerical simulations, expanded discussio

Blocking Coloured Point Sets

This paper studies problems related to visibility among points in the plane. A point $x$ \emph{blocks} two points $v$ and $w$ if $x$ is in the interior of the line segment $\bar{vw}$. A set of points $P$ is \emph{$k$-blocked} if each point in $P$ is assigned one of $k$ colours, such that distinct points $v,w\in P$ are assigned the same colour if and only if some other point in $P$ blocks $v$ and $w$. The focus of this paper is the conjecture that each $k$-blocked set has bounded size (as a function of $k$). Results in the literature imply that every 2-blocked set has at most 3 points, and every 3-blocked set has at most 6 points. We prove that every 4-blocked set has at most 12 points, and that this bound is tight. In fact, we characterise all sets $\{n_1,n_2,n_3,n_4\}$ such that some 4-blocked set has exactly $n_i$ points in the $i$-th colour class. Amongst other results, for infinitely many values of $k$, we construct $k$-blocked sets with $k^{1.79...}$ points

Exploration of Finite 2D Square Grid by a Metamorphic Robotic System

We consider exploration of finite 2D square grid by a metamorphic robotic system consisting of anonymous oblivious modules. The number of possible shapes of a metamorphic robotic system grows as the number of modules increases. The shape of the system serves as its memory and shows its functionality. We consider the effect of global compass on the minimum number of modules necessary to explore a finite 2D square grid. We show that if the modules agree on the directions (north, south, east, and west), three modules are necessary and sufficient for exploration from an arbitrary initial configuration, otherwise five modules are necessary and sufficient for restricted initial configurations