Performance Problems (performance + problem)

Distribution by Scientific Domains

Selected Abstracts

A geometric approach to robust performance of parametric uncertain systems

J. Bondia
Abstract A new approach for the robust performance problem for parametric uncertain systems is presented. Contrary to the classical approach, where specifications must be given in the frequency domain, this approach allows to deal with classical time specifications such as bounds on the overshoot, settling time and steady state error, which are matched to an uncertain reference model. Controller synthesis is then formulated as a set inclusion problem with a clear geometrical interpretation. Copyright 2003 John Wiley & Sons, Ltd. [source]

Welfare dependency as a performance problem that requires a performance improvement approach

Riad S. Aisami PhD
Leaving the welfare system does not necessarily equate to a sustainable self-sufficiency of the dependents, as the welfare reform stipulates. Therefore, the success of the welfare reform program should be determined not by the number of dependents who leave the welfare system but by the change that the welfare reform creates in recipients' lives. From a performance improvement perspective, welfare dependency can be viewed as a performance problem that requires a performance improvement approach. [source]

Training myths: False beliefs that limit the efficiency and effectiveness of training solutions, part 1

Wallace Hannum
This article questions commonly held beliefs about training as a component of performance improvement solutions. Rather than being based on theoretical and empirical support, many beliefs about training are based on little more than myth. Part 1 of this article presents myths about the relationship of training and performance and myths about determining training content. Training fails when the performance problem is caused by something other than a lack of knowledge or skill. And it is compromised when we fail to include only the essential content. [source]

A Performance Approach to Job Analysis

Al Folsom
ABSTRACT When we think of conducting analyses with a performance view, we commonly lean toward tools like front end analysis, needs assessment, performance analysis, and several variations. Usually, this starts because of a performance problem or because of an anticipated new performance. What about existing training? We look to training evaluation in its various levels to determine whether people like it, learn from it, transfer it, and whether the organization is benefiting from it. This paper describes a scenario where existing training was occurring, people suspected it could be more efficient, and yet the individuals' performance was for the most part satisfactory. We wanted to determine where the training could be made more efficient, determine if there were other barriers to performance, and do this with valid and reliable data from a large workforce. The Coast Guard's Performance Technology Center was in its infancy and was given the permission to try out alternative methods of conducting its work. This article describes the lessons learned about the process, about the technologies employed, and even the logistics of carrying out a rather large-scale effort in minimal time. [source]

Clock synchronization in Cell/B.E. traces

M. Biberstein
Abstract Cell/B.E. is a heterogeneous multicore processor that was designed for the efficient execution of parallel and vectorizable applications with high computation and memory requirements. The transition to multicores introduces the challenge of providing tools that help programmers tune the code running on these architectures. Tracing tools, in particular, often help locate performance problems related to thread and process communication. A major impediment to implementing tracing on Cell is the absence of a common clock that can be accessed at low cost from all cores. The OS clock is costly to access from the auxiliary cores and the hardware timers cannot be simultaneously set on all the cores. In this paper, we describe an offline trace analysis algorithm that assigns wall-clock time to trace records based on their thread-local time stamps and event order. Our experiments on several Cell SDK workloads show that the indeterminism in assigning wall-clock time to events is low, on average 20,40 clock ticks (translating into 1.4,2.8,s on the system used in our experiments). We also show how various practical problems, such as the imprecision of time measurement, can be overcome. Copyright 2009 John Wiley & Sons, Ltd. [source]

Specification and detection of performance problems with ASL

Michael Gerndt
Abstract Performance analysis is an important step in tuning performance-critical applications. It is a cyclic process of measuring and analyzing performance data, driven by the programmer's hypotheses on potential performance problems. Currently this process is controlled manually by the programmer. The goal of the work described in this article is to automate the performance analysis process based on a formal specification of performance properties. One result of the APART project is the APART Specification Language (ASL) for the formal specification of performance properties. Performance bottlenecks can then be identified based on the specification, since bottlenecks are viewed as performance properties with a large negative impact. We also present the overall design and an initial evaluation of the Periscope system which utilizes ASL specifications to automatically search for performance bottlenecks in a distributed manner. Copyright 2006 John Wiley & Sons, Ltd. [source]

A test suite for parallel performance analysis tools

Michael Gerndt
Abstract Parallel performance analysis tools must be tested as to whether they perform their task correctly, which comprises at least three aspects. First, it must be ensured that the tools neither alter the semantics nor distort the run-time behavior of the application under investigation. Next, it must be verified that the tools collect the correct performance data as required by their specification. Finally, it must be checked that the tools perform their intended tasks and detect relevant performance problems. Focusing on the latter (correctness) aspect, testing can be done using synthetic test functions with controllable performance properties, possibly complemented by real-world applications with known performance behavior. A systematic test suite can be built from synthetic test functions and other components, possibly with the help of tools to assist the user in putting the pieces together into executable test programs. Clearly, such a test suite can be highly useful to builders of performance analysis tools. It is surprising that, up until now, no systematic effort has been undertaken to provide such a suite. In this paper we describe the APART Test Suite (ATS) for checking the correctness (in the above sense) of parallel performance analysis tools. In particular, we describe a collection of synthetic test functions which allows one to easily construct both simple and more complex test programs with desired performance properties. We briefly report on experience with MPI and OpenMP performance tools when applied to the test cases generated by ATS. Copyright 2006 John Wiley & Sons, Ltd. [source]

Deep Start: a hybrid strategy for automated performance problem searches

Philip C. Roth
Abstract To attack the problem of scalability of performance diagnosis tools with respect to application code size, we have developed the Deep Start search strategy,a new technique that uses stack sampling to augment an automated search for application performance problems. Our hybrid approach locates performance problems more quickly and finds performance problems hidden from a more straightforward search strategy. The Deep Start strategy uses stack samples collected as a by-product of normal search instrumentation to select deep starters, functions that are likely to be application bottlenecks. With priorities and careful control of the search refinement, our strategy gives preference to experiments on the deep starters and their callees. This approach enables the Deep Start strategy to find application bottlenecks more efficiently and more effectively than a more straightforward search strategy. We implemented the Deep Start search strategy in the Performance Consultant, Paradyn's automated bottleneck detection component. In our tests, Deep Start found half of our test applications' known bottlenecks between 32% and 59% faster than the Performance Consultant's current search strategy, and finished finding bottlenecks between 10% and 61% faster. In addition to improving the search time, Deep Start often found more bottlenecks than the call graph search strategy. Copyright 2003 John Wiley & Sons, Ltd. [source]

Videoendoscopic evaluation of the upper respiratory tract in 93 sport horses during exercise testing on a high-speed treadmill

Summary Reasons for performing study: Videoendoscopy of the upper respiratory tract (URT) during high-speed treadmill exercise has proved to be invaluable in the assessment of URT dysfunction in racehorses. However, very little information exists regarding dynamic airway collapse in other sport horses used in nonracing equestrian disciplines. Objectives: To evaluate the videoendoscopic findings at rest and during exercise in a mixed population of sport horses referred for investigation of poor athletic performance and/or abnormal respiratory noise. Methods: Videoendoscopy of the upper airway was performed at rest and during high-speed treadmill exercise in 93 horses. Results: Dynamic airway obstructions were diagnosed in 77% of horses and were frequently complex in nature. The most common forms of dynamic collapse included soft palate dysfunction (54%), dynamic laryngeal collapse (38%), axial deviation of the aryepiglottic folds (24%) and pharyngeal wall collapse (18%). In the majority of horses, no obvious abnormalities were identified at rest. Enforced poll flexion was found to be a contributing factor in 24% of cases. Conclusions: Dynamic obstructions of the URT were a common cause of poor performance and/or abnormal respiratory noise in sport horses referred for investigation of performance problems. Potential relevance: This study highlights the importance of videoendoscopic evaluation of the URT during exercise in horses utilised for equestrian sports where exercise during competition is submaximal in nature. [source]

Evaluation of operators' performance for automation design in the fully digital control room of nuclear power plants

Chiuhsiang Joe Lin
Abstract Recent technical developments in computer hardware and software have meant that human,machine systems can be automated in many respects. If automation fails, however, human operators can have difficulty in recognizing the existence of a problem, identifying what has failed, and taking corrective action to remedy these out-of-the-loop (OOTL) performance problems. Several studies have suggested that taxonomies of levels of automation (LOAs) and types of automation (TOAs) can be used to solve OOTL problems. This study examined the impact of LOAs in process control automation within the context of nuclear power plants (NPPs). A simulation experiment in an NPP is performed to validate this framework using an automatic mode and a semiautomatic mode. Mental demand is found to be significantly reduced under the automatic mode; however, participants felt frustrated with this LOA. Situation awareness is found to be similar in the two modes. The results of an end-of-experiment subjective rating reveal that participants were evenly divided between the two modes with respect to generating and selecting functions. It is therefore suggested that human operators be involved in generating and selecting functions under an automatic mode. 2009 Wiley Periodicals, Inc. [source]

Determining controller benefits via probabilistic optimization

Y. Zhou
Abstract For the most part, process control research has focussed on the synthesis and tuning of controllers, which has provided a plethora of techniques that can address virtually any application. With each new control technique, a steady stream of ,successful' application results are generated and reported. Recently, a considerable number of control researchers have turned their attention to assessing the performance of installed control systems and to the diagnosis of controller performance problems. Despite successes in the areas of controller synthesis, tuning and performance analysis, almost no research has addressed the fundamental issue of determining whether the economic performance gains that are expected accrue from a proposed process control project are sufficient to justify its execution. The work presented here proposes an optimization-based technique for calculating the expected economic performance of a given control system; a method, which is analogous to analysis of variance, for determining the expected economic benefit that will arise from a particular controller improvement effort; and a sensitivity analysis approach for determining the effect of specific assumptions on control system improvement decisions. Copyright 2003 John Wiley & Sons, Ltd. [source]

Performance analysis of data scheduling algorithms for multi-item requests in multi-channel broadcast environments

Kai Liu
Abstract Nowadays querying multiple-dependent data items in a request is common in many advanced mobile applications, such as traffic information enquiry services. In addition, multi-channel architectures are widely deployed in many data dissemination systems. In this paper, we extend a number of data productivity-based scheduling algorithms and evaluate their performance in scheduling multi-item requests in multi-channel broadcast environments. We observe from the experimental results two performance problems that render these algorithms ineffective. Lastly, we discuss possible causes of these problems to give insights in the design of a better solution. Copyright 2009 John Wiley & Sons, Ltd. [source]

Traffic locality characteristics in a parallel forwarding system

W. Shi
Abstract Due to the widening gap between the performance of microprocessors and that of memory, using caches in a system to take advantage of locality in its workload has become a standard approach to improve overall system performance. At the same time, many performance problems finally reduce to cache performance issues. Locality in system workload is the fact that makes caching possible. In this paper, we first use the reuse distance model to characterize temporal locality in Internet traffic. We develop a model that closely matches the empirical data. We then extend the work to investigate temporal locality in the workload of multi-processor forwarding systems by comparing locality under different packet scheduling schemes. Our simulations show that for systems with hash-based schedulers, caching can be an effective way to improve forwarding performance. Based on flow-level traffic characteristics, we further discuss the relationship between load-balancing and hash-scheduling, which yields insights into system design. Copyright 2003 John Wiley & Sons, Ltd. [source]

Enhancing multimedia streaming over existing wireless LAN technology using the Unified Link Layer API

Tim Farnham
This paper examines how multimedia streaming scenarios can be enhanced by cross-layer interaction, and in particular link performance information and configuration options provided by the recently developed Unified Link Layer API (ULLA). It provides results of an experimental implementation developed for this purpose in a wireless LAN (WLAN) environment. Multimedia streaming is an application that is gaining in popularity for mobile devices and in particular mobile Internet-based content broadcasting is rapidly emerging as a key feature on mobile devices. In these scenarios, the wireless link (last hop) is normally the performance bottleneck due to the dynamic and limited capacity of the wireless medium. The use of ULLA in this context can provide the ability to tailor the video transmission to the wireless link performance and also to configure the links in response to performance problems or environmental changes. For this purpose the focus of multimedia streaming has been on WLAN link technology and dynamic adaptation (i.e., dynamic channel selection and video transcoding) using a dynamic resource reservation overlay protocol. Copyright 2007 John Wiley & Sons, Ltd. [source]

Engineering of pharmaceutical materials: An industrial perspective

Kwok Chow
Abstract Crystal engineering provides a rational approach to solving formulation, processing and product performance problems. This review discusses how the concept of crystal engineering can be judiciously utilized to manipulate the solid-state properties of drugs and excipients for successful pharmaceutical formulation and process development. Existing and emerging manufacturing as well as co-processing technologies being applied in the pharmaceutical industry are also presented together with selected examples of crystal form design, crystal form selection and crystal modifications for illustration purposes. 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97: 2855,2877, 2008 [source]

Reliability and validity of the Canadian Occupational Performance Measure for clients with psychiatric disorders in Taiwan

Dr Ay-Woan Pan
Abstract The purpose of the study was to examine the reliability and validity of the Canadian Occupational Performance Measure (COPM) in Taiwanese clients with psychiatric disorders. The COPM was translated into Mandarin and tested on 141 Taiwanese clients. The average age of the clients was 35.6 years; 94% were diagnosed with schizophrenia. The results of the study showed that the test,retest reliability of the COPM was r=0.842. The COPM identified occupational performance problems that included self-care (37%), productivity (25%), and leisure occupations (20%). Fifty percent of the therapists were receptive in adapting the client-centred approach and applying the COPM in their clinical practice. It was concluded that the COPM can be applied reliably to Taiwanese clients. Furthermore, the COPM was valuable in identifying information related to occupational performance that could not be identified elsewhere. Since 50% of the therapists felt reluctant about the appropriateness of the client-centred approach in their culture, it was important to examine the gap between clients' judgements and actual performance, as well as to evaluate the feasibility of the client-centred concept in clinical practice. Finally, the concept of the client-centred approach needs to be disseminated and communicated to the occupational therapy profession in order that the COPM can be adequately applied in mental health practice. Copyright 2003 Whurr Publishers Ltd. [source]

Occupational performance in older stroke wheelchair users living at home

Dr Denise T Reid Professor, Faculty of Medicine
Abstract This research aimed to identify problems in occupational performance experienced by survivors of stroke who used a wheelchair, both from their perspective and from the perspective of their caregivers. Sixteen stroke survivors over the age of 65 years who had used a prescribed wheelchair for at least one year, who lived in their own home, who were able to participate in a conversational interview and who had a caregiver willing to participate comprised the sample. The Canadian Occupational Performance Measure (COPM) was used to identify occupational performance problems and to measure stroke survivors' and caregivers' perceptions of performance. The Functional Autonomy Measurement System (SMAF) was also used to evaluate the functional performance of stroke survivors from the caregivers' perspective. The frequency and type of problems identified by the COPM were descriptively analysed and compared for both groups. The results of Mann-Whitney U tests showed no differences in the frequency of self-care, productivity and leisure problems reported between the two groups. Within-group comparisons using the Wilcoxon Signed Ranks Test showed that stroke survivors identified significantly more self-care problems than productivity-type problems (p=0.001), and more leisure problems than productivity problems (p=0.013). Caregivers identified significantly more self-care problems than productivity problems (p=0.001). The most common self-care problems reported by both stroke survivors and caregivers were dressing and bathing. Results suggest a high level of functional disability among the stroke survivors. There was a significant correlation between the score on the SMAF Instrumental Activities of Daily Living subscale and the frequency of caregiver assistance (r=0.747, p=0.001). Addressing the perspectives of both stroke survivors who are wheelchair users and their caregivers in identifying occupational performance problems at home is important for occupational therapists for planning home-based intervention. Copyright 2001 Whurr Publishers Ltd. [source]

Current status, future trends, and issues in human performance technology, part 1: Influential domains, current status, and recognition of HPT

James A. Pershing
Fifteen human performance technology experts participated in a survey investigating HPT's current status, future trends, and issues. Although HPT is not fully recognized in many organizations, such strengths as systems thinking and multidisciplinary approaches to performance problems are valued. Weaknesses reported are the rare use of HPT in small organizations, falling for quick fixes, and shortcomings in evaluation. HPT professionals need to do better at clarifying HPT principles, communicating HPT values, and demonstrating HPT's organizational impact. [source]

Object-Oriented Performance Improvement

Ian Douglas
ABSTRACT In this paper, a framework to support an object-oriented approach to performance analysis is described. The framework includes the use of collaboration, automation, visual modeling, and reusable repositories of analysis knowledge. The need for a new framework is related to the increasing concern with the cost effectiveness of student and employee development. Efforts to improve the return-on-investment in such development have been hindered by a craft orientation to the design and construction of learning and performance support materials. One solution to this problem has been to enhance the reuse of such materials. Rather than build every new system from scratch in a craft-oriented manner, it is envisioned that systems will be constructed largely of standardized, reusable objects shared through Web-based repositories. Currently, the main focus is on the technological framework necessary for an object-based approach to learning system development. There appears to be little consideration of the changes in analysis and design thinking required for the move towards object-based systems. Such systems should still be required to be directly linked to performance problems and opportunities at both the organizational and individual system levels. [source]

Cognitive strategy use by children with Asperger's syndrome during intervention for motor-based goals

Sylvia Rodger
Background:,Cognitive Orientation for (daily) Occupational Performance (CO-OP) is a cognitive approach utilised by occupational therapists to help guide children in the discovery of appropriate strategies for effective task performance through a structured problem-solving process. There has been limited research into its utility for children with Asperger's syndrome (AS). These children often present with motor difficulties, although these are not required for diagnosis of the syndrome. A recent study found that children with AS were able to use the CO-OP framework to enhance their performance of motor-based goals. Methods:,This paper presents two case studies demonstrating the use of CO-OP with children with AS, and explores the global and domain-specific strategies and types of guidance utilised to improve their task performance. Two children with AS, aged 9 and 11, with above average intellectual ability, engaged in 10 sessions of CO-OP. All sessions were videotaped. One hundred minutes of randomly selected footage were coded per child using the Observer Software Package version 5.0. Results:,The mean interrater agreement for the two children was 94.06% and 89.30%. Both children (i) utilised the global strategies ,do', followed by ,plan' and ,check', (ii) used at least three domain-specific strategies in each session with ,task specification/modification' and ,body position' utilised most, and (iii) used limited verbal self-guidance. Conclusion:,These two children with AS were able to utilise cognitive strategies to effectively solve their motor performance problems. Children with AS and those with DCD used similar strategies to achieve motor goals. CO-OP appears to have potential as an effective intervention for children with AS. Study limitations, clinical implications and directions for future research are discussed. [source]

The Use of Simulation in the Development of Individual Cognitive Expertise in Emergency Medicine

William Bond MD
Abstract This consensus group from the 2008 Academic Emergency Medicine Consensus Conference, "The Science of Simulation in Healthcare: Defining and Developing Clinical Expertise," held in Washington, DC, May 28, 2008, focused on the use of simulation for the development of individual expertise in emergency medicine (EM). Methodologically sound qualitative and quantitative research will be needed to illuminate, refine, and test hypotheses in this area. The discussion focused around six primary topics: the use of simulation to study the behavior of experts, improving the overall competence of clinicians in the shortest time possible, optimizing teaching strategies within the simulation environment, using simulation to diagnose and remediate performance problems, and transferring learning to the real-world environment. Continued collaboration between academic communities that include medicine, cognitive psychology, and education will be required to answer these questions. [source]

Disability and the Performance Paradox: Can Social Capital Bridge the Divide?

Kelly Williams-Whitt
This research captures the physical and social experience of disability by analysing the practical performance problems that arise when an ill or injured employee returns to work, and documenting how those problems are interpreted. The grounded theory approach suggests an alternative to the traditional biomedical or social perspectives on disability. Field research reveals four themes: attendance, disciplinary history, peer interaction and task function. Managerial and co-worker perceptions were significantly affected by interactions that occurred before any disability was known to exist. Historic patterns of social exchange strongly suggest that social capital theory explains problematic work performance. [source]