Measurement of wide frequency range structural microvibrations with a pocket digital camera and sub-pixel techniques

Analysis of vibrations and displacements is a hot topic in structural engineering. Although there is a wide variety of methods for vibration analysis, direct measurement of displacements in the mid and high frequency range is not well solved and accurate devices tend to be very expensive. Low-cost systems can be achieved by applying adequate image processing algorithms. In this paper, we propose the use of a commercial pocket digital camera, which is able to register more than 420 frames per second (fps) at low resolution, for accurate measuring of small vibrations and displacements. The method is based on tracking elliptical targets with sub-pixel accuracy. Our proposal is demonstrated at a 10 m distance with a spatial resolution of 0.15 mm. A practical application over a simple structure is given, and the main parameters of an attenuated movement of a steel column after an impulsive impact are determined with a spatial accuracy of 4 µm.

A time scale for measuring the adaptability of school systems with an instrument, scoring method and standards for the measurement of such adaptability,

Mode of access: Internet.

Federal workforce quality : measurement and improvement : a report to the U.S. Merit Systems Protection Board and the U.S. Office of Personnel Management.

Shipping list no.: 92-0508-P.

Standards and tests for the measurement of the efficiency of schools and school systems,

cont. VI. The application of standard measurements to school administration. [By] D.C. Bliss. VII. A half-year's progress in the achievement of one school system. A. The progress as measured by the Thorndike visual vocabulary test. B. The progress as measured by the Courtis tests, series B. [By] H.G. Childs. VIII. Courtis tests in arithmetic: value to superintendents and teacher. [By] S.A. Courtis. IX. Use of standard tests at Salt Lake City, Utah. [By] E. P. Cubberley. X. Reading. [By] C.H. Judd. XI. Studies by the Bureau of research and efficiency of Kansas City, Mo. [By] George Melcher. XII. The effects of efficiency tests in reading on a city school system. [By] E.E. Oberholtzer. XIII. Investigation of spelling in the schools of Oakland, Cal. [By] J.B. Sears. XIV. Standard tests as aids in the classification and promotion of pupils. [By] Daniel Starch. XV. The use of mental tests in the school. [By] G.M. Whipple.

Performance measurement based co-ordination of enterprise resource planning systems in a virtual enterprise

As the backbone of e-business, Enterprise Resource Planning (ERP)system plays an important role in today's competitive business environment. Few publications discuss the application of ERP systems in a virtual enterprise (VE). A VE is defined as a dynamic partnership among enterprises that can bring together complementary core competencies needed to achieve a business task. Since VE strongly emphasises partner cooperation, specific issues exist relative to the implementation of ERP systems in a VE. This paper discusses the use of VE Performance Measurement System(VEPMS) to coordinate ERP systems of VE partners. It also defines the framework of a `Virtual Enterprise Resource Planning (VERP) system', and identifies research avenues in this field.

Evaluation and measurement of multiprocessor systems with shared memory

This study is concerned with several proposals concerning multiprocessor systems and with the various possible methods of evaluating such proposals. After a discussion of the advantages and disadvantages of several performance evaluation tools, the author decides that simulation is the only tool powerful enough to develop a model which would be of practical use, in the design, comparison and extension of systems. The main aims of the simulation package developed as part of this study are cost effectiveness, ease of use and generality. The methodology on which the simulation package is based is described in detail. The fundamental principles are that model design should reflect actual systems design, that measuring procedures should be carried out alongside design that models should be well documented and easily adaptable and that models should be dynamic. The simulation package itself is modular, and in this way reflects current design trends. This approach also aids documentation and ensures that the model is easily adaptable. It contains a skeleton structure and a library of segments which can be added to or directly swapped with segments of the skeleton structure, to form a model which fits a user's requirements. The study also contains the results of some experimental work carried out using the model, the first part of which tests• the model's capabilities by simulating a large operating system, the ICL George 3 system; the second part deals with general questions and some of the many proposals concerning multiprocessor systems.

I&R Systems on the Internet/Intranet Cites as the Tool for Distance Learning

This article considers the Internet/Intranet information systems as the tool for distance learning. Author considers the model of the 3-tier WEB based information system, the idea of the language for implementing and customized solution, which includes the original language and processor for fast prototyping and implementing small and middle sized Internet/Intranet information systems.

A Distance-Based Method for Attribute Reduction in Incomplete Decision Systems

There are limitations in recent research undertaken on attribute reduction in incomplete decision systems. In this paper, we propose a distance-based method for attribute reduction in an incomplete decision system. In addition, we prove theoretically that our method is more effective than some other methods.

Field investigation of contactless displacement measurement using computer vision systems for civil engineering applications

Much of the bridge stock on major transport links in North America and Europe was constructed in the 1950s and 1960s and has since deteriorated or is carrying loads far in excess of the original design loads. Structural Health Monitoring Systems (SHM) can provide valuable information on the bridge capacity but the application of such systems is currently limited by access and bridge type. This paper investigates the use of computer vision systems for SHM. A series of field tests have been carried out to test the accuracy of displacement measurements using contactless methods. A video image of each test was processed using a modified version of the optical flow tracking method to track displacement. These results have been validated with an established measurement method using linear variable differential transformers (LVDTs). The results obtained from the algorithm provided an accurate comparison with the validation measurements. The calculated displacements agree within 2% of the verified LVDT measurements, a number of post processing methods were then applied to attempt to reduce this error.

Laboratory investigation of contactless displacement measurement using computer vision systems

Much of the bridge stock on major transport links in North America and Europe was constructed in the 1950’s and 1960’s and has since deteriorated or is carrying loads far in excess of the original design loads. Structural Health Monitoring Systems (SHM) can provide valuable information on the bridge capacity but the application of such systems is currently limited by access and system cost. This paper investigates the development of a low cost portable SHM system using commercially available cameras and computer vision techniques. A series of laboratory tests have been carried out to test the accuracy of displacement measurements using contactless methods. The results from each of the tests have been validated with established measurement methods, such as linear variable differential transformers (LVDTs). A video image of each test was processed using two different digital image correlation programs. The results obtained from the digital image correlation methods provided an accurate comparison with the validation measurements. The calculated displacements agree within 4% of the verified measurements LVDT measurements in most cases confirming the suitability full camera based SHM systems

Predicting difficult laryngoscopy using ultrasound measurement of distance from skin to epiglottis

Unpredicted difficult intubation can have severe consequences, and it is a significant source of morbidity and mortality. Although recent studies indicate that specific ultrasonography (US) measurements may be predictors of difficult laryngoscopy, their use is still limited, and its quantification is missing. The purpose of this prospective observational study is to evaluate the use of US-measured distance from skin to epiglottis (DSE) for difficult laryngoscopy prediction.

The effect on CO2 emissions of taxing truck distance in retail transports

To finance transportation infrastructure and to address social and environmental negative externalities of road transports, several countries have recently introduced or consider a distance based tax on trucks. In competitive retail and transportation markets, such tax can be expected to lower the demand and thereby reduce CO2 emissions of road transports. However, as we show in this paper, such tax might also slow down the transition towards e-tailing. Considering that previous research indicates that a consumer switching from brick-and-mortar shopping to e-tailing reduces her CO2 emissions substantially, the direction and magnitude of the environmental net effect of the tax is unclear. In this paper, we assess the net effect in a Swedish regional retail market where the tax not yet is in place. We predict the net effect on CO2 emissions to be positive, but off-set by about 50% because of a slower transition to e-tailing.