Effect of body posture and common hand tools on peak torque exertion capabilities

An experimental investigation was conducted to investigate the effects of body posture and of different types of common non-powered hand tools on maximum volitional torque exertion capabilities of males and females. Thirty-six males and 14 females applied peak torque in 21 different body postures while using nine different hand tools. The data analysis indicated that, for both males and females, the magnitude of volitional torque is strongly influenced by the type of tool used and the posture assumed. Between the two, however, the effect of hand tool is more profound. The correlation between the tool type and volitional torque was of the order of 0.71. No other variable was as strongly correlated with volitional torque. Maximum volitional torque profiles, as a function of posture and tool type, are provided for males and females.     

On kineopsis and computation of structure and motion

This correspondence deals with the computation of structure and motion of rigid objects in space from image positions and optical flow. A test for rigid motion of objects in space is introduced which yields a new formulation of the problem. Assuming a central projection model for the viewing system, it is shown that image positions and optical flow at four points can achieve this perception.     

Detection of intensity changes with subpixel accuracy using laplacian-gaussian masks

We present a system that takes a gray level image as input, locates edges with subpixel accuracy, and links them into lines. Edges are detected by finding zero-crossings in the convolution of the image with Laplacian-of-Gaussian (LoG) masks. The implementation differs markedly from M.I.T.'s as we decompose our masks exactly into a sum of two separable filters instead of the usual approximation by a difference of two Gaussians (DOG). Subpixel accuracy is obtained through the use of the facet model [1]. We also note that the zero-crossings obtained from the full resolution image using a space constant ? for the Gaussian, and those obtained from the 1/n resolution image with 1/n pixel accuracy and a space constant of ?/n for the Gaussian, are very similar, but the processing times are very different. Finally, these edges are grouped into lines using the technique described in [2].     

A Chinese information processing system

The Chinese information processing system(CIPS)introduced in this paper can producegraphs,tables,flowcharts,mathematical equations,forms and also provides typesettingfacilities.The system can process not only Chinese text but also English text or a mixture ofthem.It is written in C language and runs on VAX Ⅱ/780 under Unix operating system.TheCIPS system is very easy to use and provides user-defined macro which allows abbreviationsof commonly used Chinese phrases and reduce the complexity of Chinese characters coding.     

Traumatogenic factors affecting the knees of carpet installers

An ergonomics analysis of carpet installation tasks was performed. The purpose was to identify and quality potential sources of biomechanical trauma that may be responsible for the high rates of knee morbidity found by previous researchers among carpet layers. Nine carpet layers were studied either at an apartment building worksite or at a training school. Results from a job analysis indicated that workers spent approximatately 75% of their time in the kneeling position using a tool called a knee-kicker to stretch and install carpet. Awkward body postures were identified from films of workers installing carpets. At the moment of impact the knee is severely flexed, subtended angles were less than 60 degrees. To obtain measures of impact force on the knee, the kicker-tool was instrumented with a load cell. Workers who executed the hardest kicks with the tool produced impact peak forces that averaged 3019 newtons (N), which is equivalent to about four times body weight. Measures from an accelerometer attached to the worker's knee showed values in ecxess of 120 m/s², which are comparable to those found during vigorous running and jumping exercises. The results imply that repetitive impact of the knee joint from the use of the knee-kicker combined with knee flexion, kneeling and squatting may be responsible for the high level of occupational knee-morbidity found among carpet layers.     

Tomographic reconstruction from experimentally obtained cone-beam projections

Direct reconstruction in three dimensions for two-dimensional projection data has been achieved by cone-beam reconstruction techniques. In this paper explicit formulas for a cone-beam convolution and back-projection reconstruction algorithm are given in a form which can be easily coded for a computer. The algorithm is justified by analyzing tomographic reconstructions of a uniformly attenuating sphere from simulated noisy projection data. A particular feature of this algorithm is the use of a one-dimensional rather than two-dimensional convolution function, greatly speeding up the reconstruction. The technique is applicable however large the cone angle of data capture and correctly reduces to the pure fan-beam reconstruction technique in the central section of the cone. The method has been applied to data captured on a cone-beam CT scanner designed for bone mineral densitometry.