A new selection operator for genetic algorithms that balances between premature convergence and population diversity

The research objective is to find a balance between premature convergence and population diversity with respect to genetic algorithms (GAs). We propose a new selection scheme, namely, split-based selection (SBS) for GAs that ensures a fine balance between two extremes, i.e. exploration and exploitation. The proposed selection operator is further compared with five commonly used existing selection operators. A rigorous simulation-based investigation is conducted to explore the statistical characteristics of the proposed procedure. Furthermore, performance evaluation of the proposed scheme with respect to competing methodologies is carried out by considering 14 diverse benchmarks from the library of the traveling salesman problem (TSPLIB). Based on t-test statistic and performance index (PI), this study demonstrates a superior performance of the proposed scheme while maintaining the desirable statistical characteristics

Pen-based Methods For Recognition and Animation of Handwritten Physics Solutions

There has been considerable interest in constructing pen-based intelligent tutoring systems due to the natural interaction metaphor and low cognitive load afforded by pen-based interaction. We believe that pen-based intelligent tutoring systems can be further enhanced by integrating animation techniques. In this work, we explore methods for recognizing and animating sketched physics diagrams. Our methodologies enable an Intelligent Tutoring System (ITS) to understand the scenario and requirements posed by a given problem statement and to couple this knowledge with a computational model of the student\u27s handwritten solution. These pieces of information are used to construct meaningful animations and feedback mechanisms that can highlight errors in student solutions. We have constructed a prototype ITS that can recognize mathematics and diagrams in a handwritten solution and infer implicit relationships among diagram elements, mathematics and annotations such as arrows and dotted lines. We use natural language processing to identify the domain of a given problem, and use this information to select one or more of four domain-specific physics simulators to animate the user\u27s sketched diagram. We enable students to use their answers to guide animation behavior and also describe a novel algorithm for checking recognized student solutions. We provide examples of scenarios that can be modeled using our prototype system and discuss the strengths and weaknesses of our current prototype. Additionally, we present the findings of a user study that aimed to identify animation requirements for physics tutoring systems. We describe a taxonomy for categorizing different types of animations for physics problems and highlight how the taxonomy can be used to define requirements for 50 physics problems chosen from a university textbook. We also present a discussion of 56 handwritten solutions acquired from physics students and describe how suitable animations could be constructed for each of them

Surgical treatment of zygomatic bone fracture using two points fixation versus three point fixation-a randomised prospective clinical trial

<p>Abstract</p> <p>Background</p> <p>The zygoma plays an important role in the facial contour for both cosmetic and functional reasons; therefore zygomatic bone injuries should be properly diagnosed and adequately treated. Comparison of various surgical approaches and their complications can only be done objectively using outcome measurements which in turn require protocol management and long-term follow up. The preference for open reduction and internal fixation of zygomatic fractures at three points has continued to grow in response to observations of inadequate results from two point and one point fixation techniques.</p> <p>The objectives of this study were to compare the efficacy of zygomatic bone after treatment with ORIF using 2 point fixation and ORIF using 3 point fixation and compare the outcome of two procedures.</p> <p>Methods</p> <p>100 patients were randomly divided equally into two groups. In group A, 50 patients were treated by ORIF using two point fixation by miniplates and in group B, 50 patients were treated by ORIF using three point fixation by miniplates. They were evaluated for their complications during and after surgery with their advantages and disadvantages and the difference between the two groups was observed.</p> <p>Results</p> <p>A total of 100 fractures were sustained. We found that postoperative complication like decreased malar height and vertical dystopia was more common in those patients who were treated by two point fixation than those who were treated with three point fixation.</p> <p>Conclusions</p> <p>Based on this study open reduction and internal fixation using three point fixation by miniplates is the best available method for the treatment zygomatic bone fractures.</p

The aggregate association index and its extensions

Research Doctorate - Doctor of Philosophy (PhD)The analysis of aggregate data from 2x2 contingency tables has a long and interesting history. Traditionally, the approach taken to estimate the unknown cell frequencies (or some function of them) is to use ecological inference (EI). However, EI relies on assumptions that are either untestable or are unrealistic. Rather than adopting strategies to estimate the unknown cells, one may instead focus on understanding the underlying association structure between the variables using the <i>Aggregate Association Index</i> (AAI). Given only the aggregate data, the AAI quantifies how likely it is that an association exists between two nominal dichotomous variables when a test of independence is performed at the α level of significance. Such a test therefore relies on Pearson’s chi-squared statistic and does so in terms of the conditional proportion P₁. Here, P₁ is the proportion of individuals/subjects classified into the first column category of the 2x2 table given that they are classified into the first row category. This thesis discusses and expands upon the AAI which was proposed less than a decade ago. The generalisations and variants of the original AAI that we propose highlight the emerging growth of this index in the context of aggregate data analysis and how the AAI overcomes many of the pitfalls that confront the analyst when performing EI. We generalise the AAI to incorporate various linear transformations related to P₁ and demonstrate the invariance of the index to <i>any</i> linear transformation; for example, such transformations include the independence ratio, Pearson contingency, standardised residual and adjusted residual. We also show how the AAI is linked to one of the most common measures of association used to analyse 2x2 contingency tables – the odds ratio. The link between the AAI and odds ratio is investigated further as we establish the theoretical relationship between the index and the extended hypergeometric distribution. In doing so, the analyst may consider any <i>a priori</i> association structure using a new variant of the AAI called the <i>Extended Aggregate Association Index</i> (EAAI). Further extensions of the AAI are also made by generalising the index to incorporate the structure of ordered dichotomous variables. This is achieved by examining the features of ordinal log-linear models and how they may be used to analyse aggregate data. Since the underlying statistic that we shall be using is Pearson’s chi-squared statistic, its magnitude (and therefore the magnitude of the AAI) is strongly influenced by the size of the sample being studied. So, this thesis examines the impact of the sample size on the AAI and proposes strategies to minimise the impact of the sample size on the magnitude of the index. We also introduce the pseudo p-value so that the analyst can evaluate the relative significance of the AAI while isolating the impact of the sample size. Another new measure of association for analysing aggregate data is proposed in this thesis – the <i>Aggregate Informative Index</i> (AII). This index provides insight into how informative the aggregate data of a 2x2 table is for assessing the association between the two dichotomous variables. We also propose an F-statistic to test the statistical significance of the observed AII for a given sample size

Wizard Of Wii : Ttoward Understanding Player Experience In First Person Games With 3D Gestures

We present a user study that begins to explore aspects of players experience in first person games that use 3D gestures for interaction. Our study uses Wizard of Wii, a video game prototype that has players perform a set of 25 distinct gestures over the course of four different game quests using the Nintendo Wii Remote. Our results indicate that players\u27 ability to recall gestures improved with repeated play and they believed themselves to be performing better in the game. However, while the recognition accuracy improved significantly with repeated play, players were unable to perceive the difference. Copyright 2011 ACM

Physicsbook: A Sketch-Based Interface For Animating Physics Diagrams

In all human-robot interaction, trust is an important element to consider because the presence or absence of trust certainly impacts the ultimate outcome of that interaction. Limited research exists that delineates the development and maintenance of this trust in various operational contexts. Our own prior research has investigated theoretical and empirically supported antecedents of human-robot trust. Here, we describe progress to date relating to the development of a comprehensive human-robot trust model based on our ongoing program of research. © 2012 Authors

PhysicsBook: A Sketch-based Interface for Animating Physics Diagrams

We present PhysicsBook, a prototype system that enables users to solve physics problems using a sketch-based interface and then animates any diagram used in solving the problem to show that the solution is correct. PhysicsBook recognizes the diagrams in the solution and infers relationships among diagram components through the recognition of mathematics and annotations such as arrows and dotted lines. For animation, PhysicsBook uses a customized physics engine that provides entry points for hand-written mathematics and diagrams. We discuss the design of PhysicsBook, including details of algorithms for sketch recognition, inference of user intent and creation of animations based on the mathematics written by a user. Specifically, we describe how the physics engine uses domain knowledge to perform data transformations in instances where it cannot use a given equation directly. This enables PhysicsBook to deal with domains of problems that are not directly related to classical mechanics. We provide examples of scenarios of how PhysicsBook could be used as part of an intelligent tutoring system and discuss the strengths and weaknesses of our current prototype. Lastly, we present the findings of a preliminary usability study with five participants

Applying Mathematical Sketching To Sketch-Based Physics Tutoring Software

We present a prototype sketch-based physics tutoring system that combines mathematical sketching, an interaction paradigm that supports construction of dynamic illustrations using the association of handwritten mathematical expressions with drawings to govern animation behavior, and a custom physics engine. We highlight key features of our core system that focus on correcting approximately drawn sketches and maintaining the correspondence between imprecise handwritten drawings and precise mathematical specifications. We describe the behavior and design of the system in detail and finally, present two example scenarios illustrating its possible uses in an educational setting. © 2010 Springer-Verlag Berlin Heidelberg

Towards Intelligent Motion Inferencing In Mathematical Sketching

We present a new approach for creating dynamic illustrations to assist in the understanding of concepts in physics and mathematics using pen-based interaction. Our approach builds upon mathematical sketching by combining the ability to make associations between handwritten mathematics and free-form drawings with an underlying physics engine. This combination lets users create animations without having to directly specify object behavior with position functions through time, yet still supports writing the mathematics needed to formulate a problem. This functionality significantly expands the capabilities of mathematical sketching to support a wider variety of dynamic illustrations. We describe our approach to creating this mathematical sketching/physics engine fusion and discuss how it provides a foundation for using mathematical sketching in intelligent tutoring systems. Copyright 2010 ACM