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排序方式: 共有803条查询结果,搜索用时 15 毫秒
71.
Arun K. Nanda Honda Shing Ten-Hwan Tzen Lionel M. Ni 《Journal of Parallel and Distributed Computing》1991,12(4)
A standard metric conventionally employed to compare the performance of different multiprocessor systems is speedup. Although providing a measure of the improvement in execution speed achievable on a system, this metric does not yield any insight into the factors responsible for limiting the potential improvement in speed. This paper studies the performance degradation in shared-memory multiprocessors as a result of contention for shared-memory resources. A replicate workload framework with a flexible mechanism for workload specification is proposed for measuring performance. Two normalized performance metrics—efficiency and overhead factor—are introduced to quantify the factors limiting performance and facilitate comparison across architectures. Finally, the proposed model is employed to measure and compare the performance of three contemporary shared-memory systems, with special emphasis on the newly released BBN Butterfly-II (TC2000), currently undergoing Beta test. 相似文献
72.
Face Detection: A Survey 总被引:5,自引:0,他引:5
In this paper we present a comprehensive and critical survey of face detection algorithms. Face detection is a necessary first-step in face recognition systems, with the purpose of localizing and extracting the face region from the background. It also has several applications in areas such as content-based image retrieval, video coding, video conferencing, crowd surveillance, and intelligent human–computer interfaces. However, it was not until recently that the face detection problem received considerable attention among researchers. The human face is a dynamic object and has a high degree of variability in its apperance, which makes face detection a difficult problem in computer vision. A wide variety of techniques have been proposed, ranging from simple edge-based algorithms to composite high-level approaches utilizing advanced pattern recognition methods. The algorithms presented in this paper are classified as either feature-based or image-based and are discussed in terms of their technical approach and performance. Due to the lack of standardized tests, we do not provide a comprehensive comparative evaluation, but in cases where results are reported on common datasets, comparisons are presented. We also give a presentation of some proposed applications and possible application areas. 相似文献
73.
Christina Soh Boon Siong Neo M. Lynne Markus 《The Journal of Strategic Information Systems》1993,2(4)
In April 1992, the Singapore Government announced its information technology (IT) vision and plan for the next 15 years to turn Singapore into ‘an intelligent island’, providing a strategic regional switching centre for expertise, goods, services and information. At the heart of this plan is a national information infrastructure that would capitalize on information as a key factor of production and an important ingredient for enhancing the quality of life of its people. Code named ‘IT2000’, the plan was developed by 60 senior managers at the National Computer Board in 1991 with participation and inputs from about 200 business and industry leaders, domain experts and academics. This paper describes the background of Singapore's drive into the information age, the IT2000 planning process, the roles of various participants and the main recommendations of the plan. An evaluation of IT2000 is made in terms of its objectives, its unanticipated results and its impacts on industry participants. Implications and lessons are drawn for strategic IT planning at the national or sectoral level. 相似文献
74.
Giannakis E Samuel CS Hewitson TD Boon WM Macris M Reeve S Lawrence J Ian Smith A Tregear GW Wade JD 《Proteomics. Clinical applications》2009,3(10):1211-1224
Kidney failure is a major health problem worldwide. Patients with end-stage renal disease require intensive medical support by dialysis or kidney transplantation. Current methods for diagnosis of kidney disease are either invasive or insensitive, and renal function may decline by as much as 50% before it can be detected using current techniques. The goal of this study was, therefore, to identify biomarkers of kidney disease (associated with renal fibrosis) that can be used for the development of a non-invasive clinical test for early disease detection. We utilized two protein-profiling technologies (SELDI-TOF MS and 2-D) to screen the plasma and kidney proteome for aberrantly expressed proteins in an experimental mouse model of unilateral uretric obstruction, which mimics the pathology of human renal disease. Several differentially regulated proteins were detected at the plasma level of day-3-obstructed animals, which included serum amyloid A1, fibrinogen α, haptoglobin precursor protein, haptoglobin and major urinary proteins 11 and 8. Differentially expressed proteins detected at the tissue level included ras-like activator protein 2, haptoglobin precursor protein, malate dehydrogenase, α enolase and murine urinary protein (all p<0.05 versus controls). Immunohistochemistry was used to confirm the up-regulation of fibrinogen. Interestingly, these proteins are largely separated into four major classes: (i) acute-phase reactants (ii) cell-signaling molecules (iii) molecules involved in cell growth and metabolism and (iv) urinary proteins. These results provide new insights into the pathology of obstructive nephropathy and may facilitate the development of specific assay(s) to detect and monitor renal fibrosis. 相似文献
75.
W M Boon H P Westerhof J S Duisterhout P V Cromme 《Computer methods and programs in biomedicine》1987,25(3):287-296
In this article the development of a computer system for General Practice, ELIAS, is described. The use of the 4th-generation software toolkit AIDA proved to be very helpful in increasing the speed of development as well as the quality of the ELIAS software. The programming support that AIDA offered, not only in increasing the rate of development but also in the flexible way in which parts of the system and the database can be adjusted (in prototyping as well as in the operational system) and its self-documenting functions, contributed to the ease of development. The consistent lay-out of the frames and uniform screen-handling, the opportunity of data validation and the availability of help information at every item in screen frames--all facilitated by AIDA--rendered ELIAS a very user-friendly system. 相似文献
76.
Boon Ping Yeo 《International journal of control》2013,86(14):1469-1474
A quasilinearization algorithm is proposed to solve optimal control problems with a scalar control variable and a scalar state inequality constraint using a transformation technique. The optimal control problem is transformed into an unconstrained problem with an auxiliary control and higher dimension. Owing to the appearance of singular arcs in the transformed problem, this is made non-singular by adding a quadratic function of the auxiliary control to its performance index. A proposed quasilinearization algorithm is then used to generate a series of solutions of the modified transformed problems which converges to the solution of the original state-constrained problem in the limit. A distinct feature of the proposed algorithm is that each modified transformed problem yields a feasible trajectory of the original state-constrained problem. Two examples have been solved to illustrate the effectiveness of the proposed quasilinearization algorithm. 相似文献
77.
78.
Assessed the potential impact of stereotypical information on memory, using 107 undergraduates. Ss saw a series of slides depicting a violent knifing incident between 2 men on the London Underground. Half were shown the altercation as occurring between 2 White men and half between a Black and a White man. In all cases, the critical slide in which the knife was presented showed it to be in the hand of the White man. After a distraction interval of 45 min Ss were given forced-choice recognition and recall tests. The latter required the Ss to write a brief account of the event while the former required Ss to choose between 2 slides. Results indicate that, when the recognition test preceded the recall test, Ss who had seen the slides with the Black and White protagonists were less accurate than those who had seen only White protagonists. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
79.
To address the wide variety of solder joint configurations, the authors have developed and applied a physics-of-failure model to predicting the service life of solder joints under thermal cycling conditions. The wide variety of solder joint geometries, materials and environments makes it impractical to develop and apply empirical models to predicting the service life of solder joint interconnects. On the other hand, a physics-of-failure model that describes the failure mechanisms in solder joints can be applied to a wide range of conditions. The physics-of-failure model framework is described and a model is demonstrated for predicting the failure of a leadless surface mount solder joint under slow thermal cycling conditions. 相似文献
80.
This study sought to determine whether the well-established relation between fraternity/sorority (Greek) membership and heavy alcohol use persists beyond the college years and whether some common third variables might account for the relation between Greek status and heavy drinking. During each of 4 years of college and 1 additional year, young adults (N ?=?319) completed measures of alcohol use, personality, alcohol expectancies, and environmental influences on drinking. Throughout the college years, Greeks consistently drank more heavily than non-Greeks. Statistically controlling for previous alcohol use did not eliminate this effect. However, Greek status did not predict postcollege heavy drinking levels. Also, perceived peer norms for heavy drinking mediated the relation between Greek affiliation and heavy alcohol use. Results are discussed in terms of situational determinants of heavy alcohol involvement in young adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献