Symbols

Author(s):  
Douglas Schenck ◽  
Peter Wilson

EXPRESS-G has three basic kinds of symbol; defintion, relation, and composition. Definition and relation symbols are used to define the contents and structure of an information model. Composition symbols enable the diagrams to be spread across many physical pages. A definition symbol is a rectangle enclosing the name of the thing being defined. The type of the definition is denoted by the style of the box. Symbols are provided for EXPRESS simple types, defined types, entity types and schemas. The EXPRESS language offers a number of predefined simple types, namely Binary, Boolean, Integer, Logical, Number, Real and String. These are the terminal types of the language. The symbol for them is a solid rectangle with a double vertical line at its right end. The name of the type is enclosed within the box, as shown in Figure 18.1. The EXPRESS Generic pseudotype is not represented in EXPRESS-G as it is only used as a formal parameter to a function or procedure, and EXPRESS-G does not have these. The symbols for the select, enumeration and defined data type are dashed boxes as shown in Figure 18.2. • The symbol for a defined data type is a dashed box enclosing the name of the type. • The symbol for a select type is a dashed box with a double vertical line at the left end, enclosing the name of the select. • The symbol for an enumeration type is a dashed box with a double vertical line at the right end, enclosing the name of the enumeration. Although an enumeration is not a terminal of the EXPRESS language (because its definition includes the enumerated things), it is a terminal of the EXPRESS-G language. Figure 18.3 shows the symbol for an entity, which is a solid rectangle enclosing the name of the entity. The symbol for a schema is shown in Figure 18.3. It is a solid rectangle divided in half by a horizontal line. The name of the schema is written in the upper half of the rectangle. The lower half of the symbol is empty. EXPRESS-G does not support any notation for either function or procedure definitions.

2020 ◽  
Vol 35 (4) ◽  
pp. 448-457
Author(s):  
Usama Tariq ◽  
Alicia Parker ◽  
Leila Saadatpour ◽  
Leilani Doty ◽  
Kenneth M Heilman

Abstract Background/Objectives Whereas rare cases of hemispatial visual neglect have been reported in patients with a neurodegenerative disease, quadrantic visuospatial neglect has not been described. We report a patient with probable posterior cortical atrophy who demonstrated lower right-sided quadrantic visuospatial neglect, together with allocentric vertical neglect. Methods/Results A 68-year-old man initially noted deficits in reading and writing. Subsequently, he developed other cognitive deficits. On vertical line bisections, he deviated upward, and on horizontal line bisections, he deviated to the left. These deviations together suggest that this man’s neglect might be most severe in his right (head/body-centered) lower (below eye level) visual space. When attempting to perform vertical line bisections in all four egocentric quadrants, his upward deviations were largest in the right lower quadrant. On a cancelation test, he revealed bilateral lower (ventral) allocentric neglect but not egocentric neglect. This patient’s magnetic resonance imaging revealed cortical atrophy, most prominent in the left parietal lobe. Discussion Previous research in stroke patients has demonstrated that the parietal lobes are important in mediating attention to contralateral and inferior visual space. The presence of left parietal atrophy may have induced this right lower (ventral) egocentric inattention as well as bilateral ventral allocentric inattention. Although to our knowledge there have been no prior reports of a patient with right lower quadrantic and lower vertical allocentric visuospatial neglect, patients are rarely tested for these forms of neglect, and this patient illustrates the importance of evaluating patients for these and other forms of neglect.


Geophysics ◽  
1955 ◽  
Vol 20 (3) ◽  
pp. 539-564 ◽  
Author(s):  
J. O. Parr ◽  
W. H. Mayne

In areas where reflection shooting is difficult, it is often necessary to attenuate the energy in a broad continuous band of disturbing wavelengths to less than a few hundredths of what would be recorded if all units were bunched together. The wavelength band of the attenuated energy should be adjacent to the band of reflection wavelengths received. Attenuation of the undesired energy is best accomplished with multiple detectors or charges. In many areas the pattern should attenuate energy horizontally propagated in all directions, not just in the direction of the detector line. Neither a finite number of uniformly effective, uniformly spaced units in line nor a uniformly effective sheet of finite length will accomplish this result. A system for gradation of the effectiveness of units described in this paper does produce this result (not only for in‐line disturbances but also for disturbances coming in from the side of the line). The attenuation band can be made broad with good attenuation or narrower with still better attenuation, as desired. The variation of effectiveness can be applied to detectors or charges arranged in a horizontal line, over a horizontal area, in a vertical line, or over a vertical area. The principle of varying effectiveness can also be applied to reversed‐polarity detectors in order to accentuate certain apparent wavelengths.


Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3462 ◽  
Author(s):  
Chunyu Qiu ◽  
Shuqing Ma ◽  
Yu Chen ◽  
Zhou Meng ◽  
Jianfei Wang

A method is developed in this paper to calculate the spatial gain of a vertical line array when the plane-wave assumption is not applicable and when the oceanic ambient noise is correlated. The proposed optimal array gain (OAG), which can evaluate the array’s performance and effectively guide its deployment, can be given by an equation in which the noise gain (NG) is subtracted from the signal gain (SG); hence, a high SG and a negative NG can enhance the performance of the array. OAGs and SGs with different array locations are simulated and analyzed based on the sound propagation properties of the direct-arrival zone (DAZ) and the reliable acoustic path (RAP) using ray theory. SG and NG are related to the correlation coefficients of the signals and noise, respectively, and the vertical correlation is determined by the structures of the multipath arrivals. The SG in the DAZ is always high because there is little difference between the multipath waves, while the SG in the RAP changes with the source-receiver range because of the variety of structure in the multiple arrivals. The SG under different conditions is simulated in this work. The “dual peak” structure can often be observed in the vertical directionality pattern of the noise because of the presence of bottom reflection and deep sound channel. When the directions of the signal and noise are close, the conventional beamformer will enhance the correlation of not only the signals but also the noise; thus, the directivity of the signals and noise are analyzed. Under the condition of having a typical sound speed profile, the OAG in some areas of the DAZ and RAP can achieve high values and even exceed the ideal gain of horizontal line array 10 logN dB, while, in some other areas, it will be lowered because of the influence of the NG. The proposed method of gain analysis can provide analysis methods for vertical arrays in the deep ocean under many conditions with references. The theory and simulation are tested by experimental data.


2020 ◽  
Author(s):  
Han-Gyeol Yeom ◽  
Sam-Sun Lee ◽  
Jo-Eun Kim ◽  
Kyung-Hoe Huh ◽  
Won-Jin Yi ◽  
...  

Abstract BackgroundThe purpose of this study was to analyze the correlation between spatial resolution and ball distortion rate of panoramic radiography and to elucidate the minimum criterion for ball distortion rate, which is very relevant to clinical readability.MethodsHorizontal and vertical spatial resolution and ball distortion rates were calculated in the same position, such as the incisor, premolar, molar, and temporomandibular joint area with various object depths corresponding to 48 mm. Three devices were evaluated. A region showing spatial resolution above the reference standard was selected, and the ball distortion rate corresponding to the same region was divided into horizontal and vertical phantom groups.The mean and standard deviation of the obtained ball distortion rates were calculated. Student’s t-test was used to statistically analyze the mean difference in ball distortion rates between vertical and horizontal phantom groups.ResultsIn all devices, the horizontal line pair phantom, but not the vertical line pair phantom, was readable in all areas measured at the line pair value of at least 1.88 lp/mm. The line pair value tended to be higher toward the center and lower toward the outside. The ball distortion rate tended to decrease closer to the center and increased further away. In addition, ball distortion rates could not be measured at some areas as they were not recognized as balls due to the high degree of distortion at the outermost and innermost sides. The number of balls satisfying the reference value using the horizontal line pair phantom was 102 (mean of ball distortion rates, 20.98; standard deviation, 15.25). The number of balls satisfying the reference value using the vertical line pair phantom was 49 (mean of ball distortion rates, 16.33; standard deviation, 14.25). However, mean ball distortion rate was not significantly different between the two groups.ConclusionsFocal layer of panoramic radiography could be evaluated by the spatial resolution using horizontal and vertical line pair phantoms and by assessing ball distortion rates through a ball-type panorama phantom. A ball distortion rate of 20% could be used as a threshold to evaluate the focal layer of panoramic radiography.


Perception ◽  
1975 ◽  
Vol 4 (1) ◽  
pp. 79-83 ◽  
Author(s):  
Harvey R Schiffman ◽  
Jack G Thompson

An experiment was performed which examined the role of figural orientation directly, and the role of an inappropriately invoked size-constancy mechanism indirectly, in the actuation and magnitude of the horizontal—vertical illusion. When the vertical line of the stimulus figure was aligned above the horizontal line, the illusory effect was significant and positive; in contrast, when the vertical line was located below the horizontal line, the illusion was negative. Under the assumption that a vertical line can appear as a foreshortened line in depth, these findings support an explanation based on the operation of a misapplied size-constancy mechanism.


2012 ◽  
Vol 25 (0) ◽  
pp. 182
Author(s):  
Jacqui Howell ◽  
Mark Symmons ◽  
George Van Doorn

The horizontal–vertical illusion (HVI) has been widely and extensively reported as a visual phenomenon in which a vertical line is perceived as shorter than a horizontal line of the same length. Like a number of geometric illusions, the HVI has also been found to occur haptically, though there is less agreement in the literature as to the extent and direction of the illusion. The relatively small number of haptic HVI papers coupled with a variety of stimuli and procedures used make it difficult to make direct comparison between the visual and haptic versions of the illusion. After a brief critical literature review, the current paper reports a study in which the visual and haptic HVIs are directly compared. In a bid to reconcile previous shortcomings, three sets of stimuli were used: L-figures, inverted T-figures, and separated horizontal and vertical lines. The stimuli were presented in two lengths: 3 and 9 cm. The dependent variable was percentage error between the horizontal and vertical — no error represents an absence of illusion. As expected, inverted T-figures produced an illusion significantly stronger than both the L-figures and single lines, which in turn did not differ from each other. Further, the illusion was present to the same extent in both modalities. Stimuli of 9 cm produced relatively stronger illusions than those that measured 3 cm, and stimulus size interacted with modality. The consequences of these findings for earlier research and proffered suggestions as to what causes this and other illusions are discussed.


1972 ◽  
Vol 34 (3) ◽  
pp. 899-902 ◽  
Author(s):  
James A. Becker

This study attempted to determine the influence of the division (bisection of the horizontal line by the vertical line) and orientation (vertical line seems longer than horizontal line) factors on the vertical-horizontal illusion. 100 Ss were divided into two groups, one with knowledge of the division and orientation factors and the other group without knowledge of these factors. The results indicated that the amount of error for the group with knowledge was significantly smaller than for the group without knowledge.


2020 ◽  
Vol 5 (1) ◽  
pp. 81
Author(s):  
Lusi Epsilawati ◽  
Ria N.Firman ◽  
Irna Sufiawati ◽  
Norlaila Sarifah ◽  
Indra Gunawan

Background: The incidence of HIV had recently increased rapidly. People infected with HIV were required to take anti-viral drugs. The severity of HIV also contributes to a decrease in bone mineral density due to taking antiviral drugs. Decreased bone density in people with HIV was a chronic disease due to the long-term use of drugs. TMD in people with HIV was often associated with several factors including emotional states such as depression. Patient infected HIV was vulnerable to TMD because it triggers physical and psychological changes. TMD and decreased bone density are common in people with HIV. Researchers hope that later there will be the latest findings that can make patients infected with HIV felt safe to take drugs without worrying about the decline in bone quality. Objective: This study aimed to investigate the value of linear measurement of the condyle position in HIV- infected children and adolescents based on panoramic radiographs in Dental Hospital Padjadjaran University. Methods: This descriptive and cross-sectional method was conducted on panoramic radiographs of HIV-infected children and adolescents since was born. Condyle position was defined by linear measurement using a protractor that divides the condyle 45° of anterior, 90° of superior, and 135° of posterior joint space from a horizontal line. The distance was then measured using a digital caliper. Results: According to linear measurements of the condyle position, all samples had abnormal linear distances in children and adolescents in all gender. The standard range of anterior joint space (Ajs) was 1.3 mm, superior joint space (Sjs) was 2.1 mm, and the posterior joint space (Pjs) was 1.8 mm. The result of this research, the right women condyle sample, the standard distance of the AJS was 0%, SJS was 16%, Pjs was 18%. While the left condyle, the usual range of the AJS was 4%, SJS was 12%, Pjs was 24%. The right men condyle sample, the standard distance of the Ajs was 0%, Sjs was 17.65%, Pjs was 11.76%. While the left condyle, the usual range of the Ajs was 0%, Sjs was 11.76%, Pjs was 5.88%. Conclusions: The abnormal distance measured was found in the condyle position of children and adolescents infected with HIV.


1978 ◽  
Vol 7 (89) ◽  
Author(s):  
Brian H. Mayoh

This paper introduces a new, simple definition of what a data type is. This definition gives one possible solution of the theoretical problems: when can an actual parameter of type T be substituted for a formal parameter of type T'? When can a type T' be implemented as another type T''? The preprint is an extended version of a paper presented at MFCS 78, Zakopane.


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