5529316
Mixture models for dynamic statistical pressure snakes
This paper introduces a new approach to statistical pressure snakes. It uses statistical modeling for both object and background to obtain a more robust pressure model. The Expectation Maximization (EM) algorithm is used to model the data into a Mixture of Gaussians (MoG). Bayesian theory is then employed as a decision making mechanism. Experimental results using the traditional pressure model and the new mixture pressure model demonstrate the effectiveness of the new models.
2626294
Computation of shape through controlled active exploration
Accurate knowledge of depth continues to be of critical importance in robotic systems. Without accurate depth knowledge, tasks such as inspection, tracking, grasping, and collision-free motion planning prove to be difficult and often unattainable. Traditional visual depth recovery has relied upon techniques that require the solution of the correspondence problem or require known lighting conditions and Lambertian surfaces. In this paper, we present a technique for the derivation of depth from feature points on a target's surface using the controlled active vision framework. We use a single visual sensor mounted on the end-effector of a robotic manipulator to automatically select feature points and to derive depth estimates for those features using adaptive control techniques. Movements of the manipulator produce displacements that are measured using a sum-of-squared difference (SSD) optical flow. The measured displacements are fed into the controller to alter the path of the manipulator and to refine the depth estimate.<<ETX>>
5822992
Active Deformable Models Using Density Estimation
This paper introduces a new approach to active deformable models. The paper starts with a brief review of the relevant approaches. We then use the Expectation Maximization and Parzen Window techniques to develop a more robust formulation for pressure snakes. The generic nature of the proposed model allows it to perform well on complex colored images. We show, by several examples, the enhanced performance of the snake under the new formulation, compared to the performance of other known snake formulations.
14452564
Eye Tracking Using Active Deformable Models
Developing a robust, non-intrusive, inexpensive eye tracker is quite a challenge in the computer vision field. This paper introduces a new eye tracking approach based on an enhanced formulation of the statistical pressure snakes. Using a head-mounted camera, to eliminate the effect of head movements, we can detect and track the eye pupil robustly. Experimental results on video sequences for normal and blinking eyes are presented with high accuracy.
41677043
Unknown object grasping using statistical pressure models
Grasping is one of the most fundamental and challenging tasks in robotics. Applications range from space missions (e.g., collection of rock samples) to industrial automation. In this work, we use a camera mounted on the end-effector of a manipulator to grasp an unknown object in the workspace. A novel deformable contour model is used to determine plausible grasp axes of the target object. Potential grasp point pairs are generated, ranked based upon measurements taken from the contour, and a vision-guided grasp of the object using the highest ranked grasp point pair is executed. Several experimental results are presented.
42411588
Computer vision issues during eye-in-hand robotic tasks
Our previous work has introduced the framework of controlled active vision that provides a bridge between computer vision and control theory. This paper presents some of the computer vision techniques that were employed in order to detect targets, automatically select features, measure feature displacements, and evaluate measurements during the various applications of the controlled active vision framework. We experimented with a lot of different techniques, but the most robust proved to be the sum-of-squared differences (SSD) optical flow technique. Search optimizations and dynamic pyramiding are proposed in order to provide real-time performance. In addition, several techniques for the evaluation of the measurements are presented. One important characteristic of these techniques is that they can also be used for the selection of features for tracking in conjunction with several numerical criteria that guarantee the robustness of the servoing. These techniques are important aspects of our work since they can be implemented either on-line or off-line. The paper concludes with results from the application of these techniques to real images.
10134033
SPE Evaluation of a Client/Server Application
This paper presents the results of a software performance evaluation of a client/server application in an Open Systems environment. Some interesting features of the design and the graphical user interface are described and their performance characteristics are evaluated. The evaluation uses a new Software Performance Engineering (SPE) tool to create software models and evaluate design alternatives.
2552665
From UML models to software performance results: an SPE process based on XML interchange formats
The SPE process uses multiple performance assessment tools depending on the state of the software and the amount of performance data available. This paper describes two XML based interchange formats that facilitate using a variety of performance tools in a plug-and-play manner thus enabling the use of the tool best suited to the analysis. The Software Performance Model Interchange Format (S-PMIF) is a common representation that is used to exchange information between (UML-based) software design tools and software performance engineering tools. On the other hand, the performance model interchange format (PMIF 2.0) is a common representation for system performance model data that can be used to move models among system performance modeling tools that use a queueing network model paradigm. This paper first defines an XML based S-PMIF based on an updated SPE meta-model Then it demonstrates the feasibility of using both the S-PMIF and the PMIF 2.0 to automatically translate an architecture description in UML into both a software performance model and a system performance model to study the performance characteristics of the architecture. This required the implementation of some extensions to the XPRIT software in order to export UML models into the S-PMIF and a new function in the SPEED software to import S-PMIF models, which are also described. The SPE process and an experimental proof of concept are presented.
45578333
Editor's Introduction
Editors’ Introduction We are pleased to present here the first issue of Studies in the Bible and Antiquity. Studies is dedicated to Latter-day Saint research on the Old Testament, New Testament, and other texts or topics that illuminate our understanding of the Bible and religion in antiquity. It is the first LDS periodical devoted exclusively to these subjects and will serve as a companion to the other periodicals of the Neal A. Maxwell Institute for Religious Scholarship dedicated to the study of the scripture and faith of the Restored Gospel. Studies in the Bible and Antiquity serves the needs of two constituencies. Like its sister publications, Studies serves a broad community of general LDS readers who study and teach the Bible and who wish to better understand both the biblical text and its world. Yet Studies is also a journal by LDS scholars for LDS scholars, as well as for our academic colleagues who have an interest in LDS approaches to the Bible and religion in antiquity. Therefore, many of the articles published here will be technical in nature. But to serve our general readership, we will work with authors of more technical studies to ensure that even the most specialized articles are as accessible as possible to nonspecialists. This inaugural issue of Studies contains five excellent articles. In “A Comparison of the Communal Lament Psalms and the TreatyCovenant Formula,” Daniel Belnap examines the communal lament psalms within the context of the Hittite covenantal formula. Belnap aptly demonstrates through many examples from the lament psalms that the relationship between Israel and Jehovah fits comfortably within the ancient Hittite treaty-covenant formula, which provides insight into how the Lord taught the Israelites about repentance and forgiveness within the context of their own time. This article has implications for our understanding of LDS covenant making, covenant breaking, and the restoration of covenantal blessings through repentance. ii • Studies in the Bible and Antiquity 1 (2009) David Bokovoy’s article, “From the Hand of Jacob: A Ritual Analysis of Genesis 27,” analyzes the element of ritual in Jacob’s deception when receiving a blessing from Isaac. Insights gleaned from Hebrew and other ancient practices suggest that hand placement, exchange of clothing, and the seeking of blessing probably relate to rituals associated with the temple. Bokovoy believes that the deception of Jacob may be better understood as a ritual act common to his environment, giving insight into a difficult-to-understand part of the book of Genesis. In “And the Word Was Made Flesh: An LDS Exegesis of the Blood and Water Imagery in the Gospel of John,” Eric D. Huntsman examines a number of Greek words and phrases that illuminate how the Gospel of John presents the symbolic nature of blood and water. It is commonly known that John, more than the other three evangelists, employed symbolism very extensively, and Huntsman has illustrated this fact well with his discussion of blood and water as symbols of the atonement of Jesus Christ. Julie M. Smith’s “Pointing Our Souls to Christ: Lessons from Leviticus” examines the Book of Leviticus analogically and shows how the ritual laws of Leviticus pointed the Israelites towards Christ and the atonement. Smith’s rereading of Leviticus, informed by contemporary exegetical method, will help readers see Leviticus not as a “dry and irrelevant” legal code, but as a witness to Christ as Savior and Redeemer. Finally, Gaye Strathearn in “The Valentinian Bridal Chamber in the Gospel of Philip” examines whether the “bridal chamber” in the Gospel of Philip may be seen as providing evidence of a primitive practice like modern LDS temple marriage. Some LDS scholars have suggested that this is the case. Strathearn carefully describes the issues and provides an accurate and insightful assessment to help readers draw informed conclusions. We now present this debut issue of Studies in the Bible and Antiquity with our hope that readers will find in its original and carefully researched articles a greater understanding and appreciation of the Bible and the biblical world.
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General Principles for Performance Oriented Design
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Best Practices for Software Performance Engineering
Performance—responsiveness and scalability—is a make-or-break quality for software. Software Performance Engineering (SPE) provides a systematic, quantitative approach to constructing software systems that meet performance objectives.It prescribes ways to build performance into new systems rather than try to fix them later. Many companies suc- cessfully apply SPE and they attest to the financial, quality, customer satisfaction and other benefits of doing it right the first time. This paper describes 24 best practices for applying SPE to proactively managing the per- formance of new applications. They are vital for successful, proactive SPE efforts, and they are among the practices of world-class SPE organizations. They will help you to establish new SPE programs and fine tune existing efforts in line with practices used by the best software development projects.