206840260
Software Performance Engineering
Performance is critical to the success of today's software systems. However, many software products fail to meet their performance objectives when they are initially constructed. Fixing these problems is costly and causes schedule delays, cost overruns, lost productivity, damaged customer relations, missed market windows, lost revenues, and a host of other difficulties. This chapter presents software performance engineering (SPE), a systematic, quantitative approach to constructing software systems that meet performance objectives. SPE begins early in the software development process to model the performance of the proposed architecture and high-level design. The models help to identify potential performance problems when they can be fixed quickly and economically.
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General Principles for Performance Oriented Design
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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.
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Designing High-Performance Distributed Applications Using Software Performance Engineering: A Tutorial
Summary This paper reviewed the purpose of SPE, the steps forapplying the SPE methods throughout the life cycle ofnew systems, the data requirements and illustrated aperformance walkthrough approach for gathering thedata. The software and system execution models forassessing the performance of alternatives weredescribed and their use throughout the life cycle wasreviewed.SPE is becoming increasingly popular for large,strategic systems to systematically manage theperformance. The models are relatively easy toconstruct and evaluate with the performance modelingtools available today. SPE’s current problems are notthe technical problems of constructing and evaluatingthe performance models. The chief barriers aremaking developers and managers aware of SPE’spotential, and persuading them to incorporate themethods into their development life cycle. References [HEID93] Ruth V. Heidel and George W. Dodson,(Editor), Special Issue on Client/Server Computing ,CMG Transactions, no. 82, 1993.[SMIT88a] Connie U. Smith, "Applying SynthesisPrinciples to Create Responsive Software Systems,"
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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.
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Performance Model Interchange Format: Semantic Validation
A Performance Model Interchange Format (PMIF) provides a mechanism whereby system model information may be transferred among queueing network model (QNM) based modeling tools. The PMIF allows diverse tools to exchange information and requires only that those tools provide importing/exporting mechanisms from/to the PMIF. The XML specification of the PMIF allows implementers to use widely available tools to parse the XML file, check the syntax, and simplify the translation to/from the XML format. Those tools, however, do not know the semantics of a QNM so they cannot check the XML to ensure that it contains a valid QNM. This paper presents the study of the validations needed to carry out such a semantic analysis, and the development of a semantic validation tool that can be used by any developer who wants to implement PMIF import/export mechanisms.
9601024
Using COTS to Construct a High Performance Robot Arm
In this paper we present a design study and technical specifications of a high performance robotic manipulator to be used for ball catching experiments using commercial off-the-shelf (COTS) components. Early evaluation shows that very good performance can be achieved using standardized PowerCube actuator modules from Amtec and a standard workstation using CAN bus communication. Implementation issues of low-level control and software platform are also described, as well as early experimental evaluation of the system.
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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.
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A Critical Appraisal of the Box Counting Method to Assess the Fractal Dimension of Tree Crowns
In this paper, we study the application of the box counting method (BCM) to estimate the fractal dimension of 3D plant foliage. We use artificial crowns with known theoretical fractal dimension to characterize the accuracy of the BCM and we extend the approach to 3D digitized plants. In particular, errors are experimentally characterized for the estimated values of the fractal dimension. Results show that, with careful protocols, the estimated values are quite accurate. Several limits of the BCM are also analyzed in this context. This analysis is used to introduce a new estimator, derived from the BCM estimator, whose behavior is characterized.
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Experiences with electronic and voice mail
Organizational computing tools are often developed and managed with an eye toward increasing efficiency. Two of today's most widespread tools are electronic mail and voice mail. They are often considered similar asynchronous communication systems, one less rich than the other. We report usage results from a single firm which adopted both electronic mail and voice mail at the same time. Survey respondents view technologies as vital to accomplishing business, but use them in quite different ways. Electronic mail was utilized to communicate with all personnel equally. In contrast, respondents communicated with their peers using voice mail more than they did up or down the corporate hierarchy. The technologies were used differently for internal and external communication. Both of these results fly in the face of information richness theory.
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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>>