The software engineering of a microcomputer application system

A system development methodology is outlined before describing its application to the development of a microcomputer system. Structured analysis techniques were used for determining the information flow through the system. The system was then structured into modules using structured design and information hiding techniques. The detailed design of the system was described in pseudocode. The system was coded in assembler supplemented by a set of structured programming macros. A systematic bottom-up testing procedure was adopted for system integration.     

Realizable feed-element patterns for multibeam reflector antenna analysis

The radiation pattern of a feed element is approximately described by a simple function(cos theta)^{q}. For a given element spacing of the feed array, we give simple formulas for estimating the practical value ofqwhen the element is an open-ended rectangular waveguide, an open-ended circular waveguide, a pyramidal horn, or a cigar antenna.     

Fatigue perturbed creep of pure aluminum at ambient temperatures

The creep of 99.999 pct pure aluminum subject to tension-tension cyclic stressing (dynamic creep) has been studied and compared to creep for the peak cyclic stress applied statically (static creep). The creep rate for a cyclic stress of 29.8 to 3.7 MPa was always found to be greater than the creep rate for static application of a stress of 29.8 MPa over the temperature range of 302 K to 348 K. The ratio of the dynamic creep rate to the static creep rate was found to increase with increasing strain and decreasing temperature. The apparent activation energy measured for dynamic creep was less than that measured for static creep. The substructure for dynamic creep is softer than for static creep and probably accounts for the accelerated creep rate and the lower observed activation energy.     

Liquid injection molding II. Mechanical design and characterization of a RIM machine

A unique liquid injection molding machine for polyurethane was designed and built to process a large quantity of polyurethane in a short period of time. This machine has a continuously variable flow rate. Using inexpensive, low capacity gear pumps, 5 gallon hydraulic accumulators were charged with fluid components. The fluid can be pumped into the accumulators at low pressure followed by nitrogen gas addition to the bladders to raise the fluid pressure, or the charging pumps can pump up the accumulators against an existing pressure. The two components were then discharged under pressure through linkage activated ball valves and mixed together in a mixing chamber. The system provided for a very low pressure loss during discharge, resulting in high fluid velocity. Extremely high flow rates were possible: approximately 1440 lb/min at 2500 psi, a pressure less than the maximum possible system pressure. This system delivers large flow rates of high quality urethane while still maintaining its simplicity, light weight, and relative low cost.     

Exploiting parallelism in 3-D object recognition using the connection machine

This paper addresses the problem of parallelism in 3-D object recognition and localization using a fine-grained SIMD architecture such as the Connection Machine^TM. The input images of partially occluding three-dimensional objects. The objects are made up of piecewise compositions of curved surfaces. The surfaces of interest are cylindrical, conical and spherical surfaces since they cover a large portion of objects encountered in an industrial environment. Qualitative classification of surfaces based on the signs of the Mean and Gaussian curvature is used to come up with Dihedral feature junctions. Dihedral feature junctions are shown to be robust to occlusion and offer a viewpoint independent scheme for modeling the object models and are well suited for matching and pose determination. Hough clustering is chosen as the constraint propagation mechanism on account of the ease of parallelization. Issues regarding parallelism on the Connection Machine^TM for every stage of the recognition and localization process such as segmentations, feature extraction matching and pose determination are discussed. Experimental results on the Connection Machine^TM bring out the advantages of exploiting parallelism for 3-D object recognition and localization on a fine-grained SIMD architecture.     

Identification of acutely isolated cells from developing rat cerebellum

Immunocytochemical staining was used to identify nerve and glial cells from postnatal rat cerebelli in situ and following tissue dissociation. Purkinje cells were identified using antibodies for the calcium-binding proteins calbindin and PEP19. Purkinje cells isolated during the second postnatal week were 15-20 microns in diameter and relatively abundant and displayed thin perisomatic processes. These features were used to identify Purkinje cells with scanning electron microscopy, which revealed extensive membrane infoldings. Golgi and nuclear cells were identified using antibodies against rat-303 antigen. Pale, nuclear, and Purkinje cells were identified using antibodies for rat-302 antigen. Although staining for rat-302 and rat-303 was weak during the second postnatal week, we were able to identify Golgi and pale cells even after tissue dissociation. Isolated Golgi cells were 8-10 microns in diameter and fewer in number than Purkinje cells and did not counterstain with calbindin antibodies. Isolated pale cells were 8-10 microns in diameter, rare, and resistant to calbindin antibodies. Isolated neurons from cerebellar nuclei were not located with either 302 or 303 staining, suggesting that they remained in the tissue. Golgi-Bergmann cells and astrocytes were identified using antibodies for glial fibrillary acidic protein. Isolated glial cells were 12-15 microns in diameter, more numerous than Purkinje cells, and unstained with calbindin antibodies. With phase-contrast optics, glial cells appeared flatter than neuronal cell types and had acentric nuclei. These results demonstrate that specific cell types in developing rat cerebellum can be identified after acute isolation, which should facilitate analysis of their endogenous properties.     

Vocal fold scarring: current concepts and management

Scarring of the vocal folds can occur as the result of blunt laryngeal trauma or, more commonly, as the result of surgical, iatrogenic injury after excision or removal of vocal fold lesions. The scarring results in replacement of healthy tissue by fibrous tissue and can irrevocably alter vocal fold function and lead to a decreased or absent vocal fold mucosal wave. The assessment and treatment of persistent dysphonia in patients with vocal fold scarring presents both diagnostic and therapeutic challenges to the voice treatment team. The common causes of vocal fold scarring are described, and prevention of vocal fold injury during removal of vocal fold lesions is stressed. The anatomic and histologic basis for the subsequent alterations in voice production and contemporary modalities for clinical and objective assessment will be discussed. Treatment options will be reviewed, including nonsurgical treatment and voice therapy, collagen injection, fat augmentation, endoscopic laryngoplasty, and Silastic medialization.     

CSTR type membrane—enzyme reactor with pulsatile inflow and constant outflow

The performance of membrane-enzyme reactor with cyclic ultrafiltration is investigated using the CSTR model proposed by Kim and Chang (1983a). The cyclic ultrafiltration is induced by a pulsatile inflow and constant outflow having the same flow rate as the mean value of the inflow. The behavior of this reactor is numerically and analytically examined. In addition, overall effectiveness is defined in order to investigate the availability of the soluble enzyme in the membrane reactor.