Abstract: To date there have been a number of efforts that attempt to characterize various aspects of the World Wide Web. This paper presents a summary of these efforts, highlighting regularities and insights that have been discovered across the variety of access points available for instrumentation. Characterizations that are derived from client, proxy, and server instrumentation are reviewed as well as efforts to characterize the entire structure of the WWW. Given the dynamic nature of the Web, it may be surprising for some readers to find that many properties of the Web follow regular and predictable patterns that have not changed in form over the Web’s lifetime. Understanding these aspects as well as those that vary is critical to designing a better Web, and as a direct consequence, creating a more enjoyable user experience.

Abstract: In this paper we present the design of SvPablo, a language independent performance analysis and visualization system that can be easily extended to new contexts with minimal changes to the software infrastructure. At present, SvPablo supports analysis of applications written in C, Fortran 77, Fortran 90, and HPF on a variety of sequential and parallel systems. In addition to capturing application data via software instrumentation, SvPablo also exploits hardware performance counters to capture the interaction of software and hardware. Both hardware and software performance data are summarized during program execution, enabling measurement of programs that execute for hours or days on hundreds of processors. This performance data is stored in a format designed to be language transparent and portable. We demonstrate the usefulness of SvPablo for tuning application programs with a case study running on an SGI Origin 2000.

Abstract: A method and system for compensating for instrumentation overhead in trace data by computing average minimum event times is provided. In order to profile a program, the program is executed to generate trace records that are written to a trace file. A set of trace event records are processed, and the trace events are represented as one or more nodes in a tree data structure. One or more performance statistics are stored at each node in the tree data structure, and a performance statistic at each node is processed to determine an overhead compensation value. The overhead compensation value is determined by computing a local overhead value for each node in the tree data structure. The total execution time of a routine corresponding to the event represented by the node is retrieved, and the local overhead value is computed as the average of the execution time over the number of calls to the routine and the number of calls from the routine to other routines. The minimum of all of the local overhead values is the maximum possible global value used as the overhead compensation value. The overhead compensation value is then applied to the performance statistic at each node.

Abstract: A method of back-tracing execution of a computer program, where the computer program comprises a plurality of blocks, comprises instrumenting an original version of the program by adding instrumentation code to some or all of the blocks to form an instrumented program. Instrumentation can be added at the binary or source level, or at link time. The instrumentation code records execution sequence information upon execution of the corresponding instrumented block to create a trace record of the executed program. The execution sequence information for each block comprises a block identifier which identifies the corresponding block. A detailed back-trace is generated, after the program has executed, by replacing each recorded block identifier with program counters associated with each instruction in the corresponding block. The application may comprise several programs or subprograms, in which case separate regions of memory can be maintained. Each region is associated with a program or subprogram or a set of programs or subprograms and stores therein part of the trace record corresponding to the associated set of programs or subprograms. The trace records themselves may be of different types. After execution, the trace record is presented to a user, in the form of assembly code, or more preferably, in the form of source level code. In an alternative embodiment, a summary of the trace record recorded during execution of an instrumented program is presented to a user. Various types of traces can be produced, including a last instruction trace and a first instruction trace.

Abstract: The invention provides a software instrumentation tool operative to control the execution of a target program, and to execute user-specified instrumentation actions upon occurrence of corresponding user-specified events during target program execution. Advantageously, the instrumentation tool permits the instrumentation actions to be implemented without modification of the target program code, and can be used to provide any desired type of instrumentation on any target program. In an illustrative embodiment, the instrumentation tool includes a frontend portion which provides a creation graphical user interface (GUI) to the tool, and a backend portion which controls execution of the target program and executes the user-specified actions. The frontend portion also includes, for a given target program, a created GUI which is created by a user for providing selected instrumentation functions for the given target program. The frontend and backend portions of the instrumentation tool may each be running on a different machine, or both may run on the same machine. The invention may be used in a wide variety of applications, including application program modification and management, fault tolerance, real-time collaboration, process monitoring, software rejuvenation and graphical interface generation.

Abstract: The present article proposes the design of a hardware-independent system for automating various analytical methods. System design is based on the division of the software into four layers, defining a communications interface among them. The definition of these layers allows the isolation of the highest, corresponding to the analytical application, from the lowest, the hardware, composed of the various parts of the block diagram. Although this system was initially designed for automating flow techniques (flow-injection analysis, FIA, and sequential-injection analysis, SIA), its conception allows the development of much more general applications, depending on the user's imagination. The system is very open, in the sense that it is not necessary to adapt the program as system possibilities are expanded. Thus, if new instrumentation (modules in the block diagram) is incorporated, one need only develop independently a minimum of software to comply with the previously defined interface. This system has been developed under the 32-bit Windows 95 environment, making the exchange of information with other applications very simple and allowing the various possibilities offered by the program to be executed simultaneously (for example, data acquisition and processing). © 1999 John Wiley & Sons, Inc. Lab Robotics and Automation 11: 131–140, 1999

Abstract: The objective of this work is to chart intriguing new possibilities and challenges resulting from the driving force and enabling factors of computing power and bandwidth that lie ahead of the instrumentation-and-measurement community. We do so by describing research and applications on the boundary between measurement, instrumentation, and virtual environments, and elucidate trends with some examples. We focus on three issues that are relevant to our view. The first issue deals with some of the essentials of instrument computer coupling. This part has a review-like character, and shows how the traditional hardware instrument was transformed into a network-accessible virtual instrument. The second issue deals with the changes in the programming paradigm and user interface of the virtual instrument. Here, we discuss how the notions of object and the advances of computer graphics transformed the programming model and the interaction of the user with it and its associated data. The third part deals with new developments, which we label virtual environments. It also deals with (sensor) data fusion in abstract environments. We show how this work can be seen as a logical fusion of the previous two developments.

Abstract: This article is directed to discuss the fundamental characteristics of measurement systems based on digital processing, with specific focus on virtual instruments and distributed measurement systems. Its goal is to point out the characteristics and the features related to issues of accuracy, precision and sensitivity, so as to achieve a better understanding of the effective usability of these technologies, avoid problems due to their superficial application, and promote the best use of these advanced, powerful methods. Finally, we consider the problem of the traceability of the measurement results coming from the instrumentation based on digital signal processing.

Abstract: A method and system for identifying sets of instructions within a computer program, execution of which serve as an indicator for processing of a transaction by the computer program and that together comprise a witness set The witness set may be employed to monitor execution of the computer program and detect processing of the transaction Witness sets are constructed by iteratively filtering an initial set of instructions based on profile data collected during execution of the computer program

Abstract: A method and system that utilize the expressiveness of hardware description languages for efficiently and comprehensively monitoring performance characteristics of a digital circuit design during simulation. According to the present invention, a design entity that is part of a digital circuit design is first described utilizing a hardware description language. Next, a counting instrument is described utilizing the same hardware description language. The counting instrument is designed to detect occurrences of a count event within the design entity during simulation of the digital circuit design. The counting instrument is associated with the design entity utilizing a non-conventional call, such that the counting instrument may be utilized to monitor each instantiation of the design entity within the simulation model without the instrumentation entity becoming incorporated into the digital circuit design. In association with the counting instrument, a linear feedback shift register is automatically generated for recording the number of occurrences of the count event within the design entity.

Abstract: Modern bioprocesses are monitored by on-line sensing devices mounted either in situ or externally. In addition to sensor probes, more and more analytical subsystems are being exploited to monitor the state of a bioprocess on-line and in real time. Some of these subsystems deliver signals that are useful for documentation only, other, less delayed systems generate signals useful for closed loop process control. Various conventional and non-conventional monitoring instruments are evaluated; their usefulness, benefits and associated pitfalls are discussed.

Abstract: Pre-defined performance tools enable instrumentation and optimization of a heterogeneous program by modifying a platform-neutral intermediate representation (IR) of the program. The intermediate representation is hierarchy of base elements that correspond to instructions, code blocks, procedures and components within the program. Each base element exports an application program interface that provides for navigation, querying and modification of the corresponding element in the hierarchy. An application program interface for the entire intermediate representation includes the application program interfaces for the individual elements along with additional functionality. A user can request instrumentation and optimization of any level of the intermediate representation hierarchy and the performance tools perform the required modifications to the intermediate representation. When a modification requires inserting instructions, the performance tools add prologue and epilog code to connect the inserted instructions with the original intermediate representation instructions. When the intermediate representation instructions are translated into platform-specific instructions and executed, the modifications made to the intermediate representation provide the instrumentation and/or optimization of the heterogeneous program.

Abstract: A computer-based apparatus provides access to complex technical information needed, for example, to maintain and repair complicated equipment, such as a motor vehicle. The apparatus includes a combined user interface and main control module to communicate with at least one remotely operated instrumentation module to control and obtain data by wireless communication. The combined user interface and main control module has an interactive display which enables the user to command the functions of the remotely deployed instrumentation module(s) and enter data through interaction with the display, as well as executes diagnostic application programs and displays information to the user. Alternatively, a separate user interface module and main control module connected by wireless communication can be provided, in which the user interface module not only commands the functions of the instrumentation module(s), but also commands remote execution of diagnostic application programs by the main control module.

Abstract: Detecting and resolving performance problems in distributed systems often requires measurements of end-to-end ("finger tip to eyeball") response times. Existing approaches embed transaction definitions in instrumentation codes. As a result, service providers (e.g., ISPs) cannot tailor transaction definitions to the usage patterns of their customers. We propose a new approach-ETE (end-to-end)-in which transaction definitions are externalized so that they can be customized. This is accomplished by having instrumentation generate events (not transactions) and employing a separate component-the transaction generator-that uses external definitions of transactions to construct response time measurements from event streams. ETE provides measurements of both end-to-end response times and their components. The latter reflect delays for services within distributed systems (e.g., name resolution service). We have used ETE to measure response times for Web transactions, terminal emulators, and Lotus Notes.

Abstract: From the Publisher: Visual Instrumentation: Optical Design and Engineering Principles details design techniques beginning with the eye itself. Authored by a team of top experts in the field, this volume provides the information needed to design and evaluate optical instruments.

Abstract: A method and system for compensating for instrumentation overhead in trace data is provided. To profile a program, the program is executed to generate trace records that are written to a trace file. A set of event trace records in a trace file is processed to determine one or more trace overhead compensation values. The trace overhead compensation values are determined by computing, for each successive pair of event trace records in the trace file, a difference between a first timestamp in a preceding event trace record and a second timestamp in a succeeding event trace record. The minimum value of all of these differences is then stored as a trace overhead compensation value representing an amount of time for instrumentation processing of an event. The one or more trace overhead compensation values are applied to the event trace records during subsequent processing of the set of event trace records.

Abstract: Over years, radical changes in engineering technology have taken place due to greatly improved instrumentation, enhanced computing power, new sensors and upgraded transmission mediums making it possible to achieve in the field what once could only be done on laboratory models. In daily life, the use of an active self-testing instrumentation endowed with a self-diagnostic capability built into the structural fabric of a machine permits us to monitor the initiation of breakdown, corrosion and erosion. This has become particularly important in such means of transportation as planes, boats and automobiles where advanced instrumentation, signal processing and pattern recognition systems operate in fairly conventional structures. By capitalizing on the technological progress in the field of instrumentation and data processing, help can be contemplated for elderly people in nursing homes through detection of abnormal situations. The continued assistance to elderly people is achieved by utilizing a technological system respectful of the elderly's privacy and operating without their active participation.

Abstract: A critical review of on-line mass spectrometry is presented, illustrating instrumentation, data treatment, and applications drawn from both control and research environments. Both direct and membrane inlets are included. The discussion of instrumentation focuses on commercially available options, although some research options that offer promise for future process applications are also mentioned briefly. Special considerations attendant upon the high-precision measurements needed for simultaneous analysis and continuous process control are emphasized. Applications illustrate a range of problems benefitting from rapid, simultaneous analysis of volatiles.

Abstract: Program errors are hard to find because of the cause-effect gap between the time when an error occurs and the time when the error becomes apparent to the programmer. Although debugging techniques such as conditional and data breakpoints help to find error causes in simple cases, they fail to effectively bridge the cause-effect gap in many situations. Dynamic query-based debuggers offer programmers an effective tool that provides instant error alert by continuously checking inter-object relationships while the debugged program is running. To speed up dynamic query evaluation, our debugger (implemented in portable Java) uses a combination of program instrumentation, load-time code generation, query optimization, and incremental reevaluation. Experiments and a query cost model show that selection queries are efficient in most cases, while more costly join queries are practical when query evaluations are infrequent or query domains are small.

Abstract: Computer systems and applications are growing more complex. Consequently, performance analysis has become more difficult due to the complex, transient interrelationships among runtime components. To diagnose these types of performance issues, developers must use detailed instrumentation to capture a large number of performance metrics. Unfortunately, this instrumentation may actually influence the performance analysis, leading the developer to an ambiguous conclusion. In this paper, we introduce a technique for focussing a performance analysis on interesting performance metrics. This technique, called dynamic statistical projection pursuit, identifies interesting performance metrics that the monitoring system should capture across some number of processors. By reducing the number of performance metrics, projection pursuit can limit the impact of instrumentation on the performance of the target system and can reduce the volume of performance data.

Abstract: This document describes a general approach to routine quality control (QC) of single-photon emission tomography (SPECT) instrumentation. Its intent is to provide recommendations, based upon good clinical practice, that both the manufacturers and the user community can support. It represents a broad spectrum of views of manufacturers, medical physicists and nuclear medicine technologists. The document’s further intent is to provide insights into the need for SPECT QC, to describe some of the critical performance parameters of a scintillation camerabased SPECT system that are likely to vary with time, and to describe in general terms the set of tests deemed most helpful for a routine QC program. Three important points must be made at the outset: 1. The purpose of routine QC is to detect changes in per formance from a baseline condition. Typically, base line characterization is performed by acceptance testing (for example, following the NEMA protocols described in NU 1, “NU 1-1994, Performance Measurement of Scintillation Cameras.”). Thus, routine QC measurements focus on the detection of a change from baseline, rather than on absolute characterization per se. 2. Performance requirements for a scintillation camerabased SPECT system are more stringent than the requirements for planar imaging with the same camera. Therefore, performing the measurements described in this document will satisfy planar imaging QC in addition to SPECT QC. 3. A routine QC program must include a sufficiently comprehensive suite of individual measurements to ensure adequate sensitivity to detection of detrimental changes in performance. At the same time, the criteria used to judge the outcome of routine QC must not be so strict as to misleadingly identify insignificant changes as important. In this regard, a routine SPECT QC program should give technologists and clinicians the data with which to decide whether: – to image patients normally, or – to image patients while putting in a call to have the system serviced, or – to put off imaging patients until the system has been serviced and fixed. In generating the recommendations described herein, several characteristics of an acceptable SPECT QC program were deemed critical: • It should not be burdensome. • It should realistically reflect the clinical use of the system. • It should emphasize measures of the stability of the system. • It should accurately reflect the adequacy of the state of the system for clinical use. Since SPECT systems vary significantly in design, it was not possible to describe in detail all measurements to be performed (for example, specific acquisition and reconstruction parameters); for this, the user is referred to the specific recommendations of the system’s manufacturer. In this regard, when specific aspects of the recommendations given herein contradict manufacturer’s specific recommendations, the manufacturer’s recommendations take precedence. One final word of caution: The fundamental design of scintillation camera-based SPECT systems results in multiple performance parameters being coupled or linked. Thus, it is likely that an electrical or mechanical change in the system will result in changes in several measured parameters. In such a situation, it is tempting to rely on the measurement of only one or two parameters (e.g., uniformity)

Abstract: The NanoWalker project is an attempt to explore a new approach in the development of various instruments. The idea is to build a small autonomous robot capable of nanometer range motions that will provide a standard platform for new miniaturized embedded instruments. This modular approach will allow easy expansion in instrumentation capability through the use of an arbitrary number of NanoWalkers which would perform similar or different measurement simultaneously on various samples. To do so, a fair amount of electronics must be embedded for infrared wireless communication, processing, support for the embedded instrument, and accurate control and drive capability for the piezo-actuated motion system. Miniaturization of the whole assembly is also a key characteristic to allow more robots to operate simultaneously within smaller surface areas. As such, new assembly techniques applicable to small volume production must be used to achieve the smallest possible implementation. The integration phase within the technological constraints is complicated by the fact that several factors such as the weight and weight distribution of the electronic assembly will have a direct impact on the very sensitive motion behavior of the robot. The NanoWalker is briefly described with the integration phases and the requirements that must be met by the assembly process.

Abstract: The present invention relates to the area of systems management teaching means and a method for determining and managing application performance. Application Response Measurement (ARM) assumes that the managed application is a self-instrumented component. This requires invasive changes to existing applications or to add explicitly code to newly written applications. Due to this additional effort this will restrict the area of applicability of ARM. The basic idea of the present invention is to instrument not the application components. The present invention contemplates instrumenting the invocation agent instead, which in turn is responsible to call the application for execution. This solution provides application response measurement without any modification of the application being measured. It is the invocation agent that makes the appropriate ARM calls to furnish the instrumentation on behalf of the application.

Abstract: This paper presents a brief description of our achievements and current research on "an artificial neural network on a field programmable gate array as a virtual sensor". One of the characteristics of many industrial processes is the complex interrelations among the variables of the process. This has lead to the development of "software sensors" (soft-sensors or virtual sensor) where, by means of a computer program, variables are estimated from the information gathered by other measurements. Our proposal is based on a modular design of a neural network on using digital nonlinear activation functions. The design methodology, the size and complexity of the synthesised hardware and the results of the tests in a real world problem are presented together with our conclusions on the viability for its wider use on instrumentation applications.

Abstract: ▪ Abstract Much of the recent rapid progress in large-scale genomic sequencing has been driven by the dramatic improvements both in the area of biological protocols and in the availability of improved laboratory instrumentation and automation platforms We discuss recent developments in the area of bioinstrumentation that are contributing to the current revolution in genetic analysis Examples of systems for laboratory automation are described together with specific single-purpose instruments Emphasis is placed on those tools that are contributing significantly to the scale-up of genomic mapping and sequencing efforts In addition, we present a selection of more advanced measurement techniques and instrumentation developments that are likely to contribute significantly to future advances in sequencing and genome analysis