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Published in Phillip A. Laplante, Dictionary of Computer Science, Engineering, and Technology, 2017
shape measure a measure such as circularity measure (compactness measure), aspect ratio, or number of skeleton nodes, which may be used to help characterize shapes as a preliminary to, or as a quick procedure for, object recognition.
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Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
shielding effectiveness Shannon's source coding theorem a major result of Claude Shannon's information theory. For lossy source coding, it gives a bound to the optimal source coding performance at a particular rate ("rate" corresponds to "resolution"). The theorem also says that the bound can be met by using vector quantization of (infinitely) high dimension. For lossless source coding, the theorem states that data can be represented (without loss of information) at a rate arbitrarily close to (but not lower than) the entropy of the data. See also rate-distortion theory. shape analysis the analysis of shapes of objects in binary images, with a view to object or feature recognition. Typically, shape analysis is carried out by measurement of skeleton topology or by boundary tracking procedures including analysis of centroidal profiles. shape from . . . the recovery of the 3-D shape of an object based on some feature (e.g., shading) of its (2-D) image. shape measure a measure such as circularity measure (compactness measure), aspect ratio, or number of skeleton nodes, which may be used to help characterize shapes as a preliminary to, or as a quick procedure for, object recognition. shape-gain vector quantization (SGVQ) a method for vector quantization where the magnitude (the gain) and the direction (the shape) of the source vector are coded separately. Such an approach gives advantages for sources where the magnitude of the input vector varies in time. shape-memory effect mechanism by which a plastically deformed object in the low-temperature martensitic condition regains its original shape when the external stress is removed and heat is applied. shape-memory smart materials include three categories, namely shape-memory alloys (SMA), shape-memory hybrid composites (SMHC), and shape-memory polymers (SMP). shaping a traffic policing process that controls the traffic generation process at the source to force a required traffic profile. shared memory characteristic of a multiprocessor system: all processors in the system share the access to main memory. In a physically shared-memory system, any processor has access to any memory location through the interconnection network. shared memory architecture a computer system having more than one processor in which each processor can access a common main memory. sharpening the enhancement of detail in an image. Processes that sharpen an image also tend to strengthen the noise in it. See edge enhancement, gradient, image enhancement, Laplacian operator, noise, Sobel operator. SHDTV See super high definition television.
Analyzing the city-level effects of land use on travel time and CO2 emissions: a global mediation study of travel time
Published in International Journal of Sustainable Transportation, 2022
This study aimed to be an analysis at a global scale of how between-city variations in land use including population density affect both travel time and CO2 emissions. Specifically, based on data compiled and edited by Nangini et al. (2019), this study differed in that the land use–travel time–carbon emission relationship was analyzed on a global scale, beyond a national/regional scale with one/several countries, using city-level emission data that were individually reported, not estimated from travel survey data or satellite images. To evaluate the mediation of travel time according to the above conceptual relationship, this study specified an SEM model. As research variables, land use characteristics were centered on population density: gross population density, proportion of the low-density built-up area (sprawl measure), and population density of the high-density built-up area (compactness measure). City-level economic, social, transportation, energy, and climate conditions were controlled for.
Exploring passenger rail markets using new station catchment size and shape metrics
Published in Journal of Spatial Science, 2018
Ting (Grace) Lin, Jianhong (Cecilia) Xia, Mark Ryan, Todd Robinson, Graham Currie, Gary McCarney, Donna Butorac
where C is the compactness of a catchment area, A is the area of a catchment area and R is the radius of the smallest circle that encloses the catchment area (Figure 4). The compactness of a catchment area of a train station is between 0 and 1. One means the catchment area is a perfect circle, i.e. the catchment is ‘completely isotropic’. If the compactness value is close to 0, the catchment area is almost a line, which means people come from only one orientation (e.g. north/south or east/west) to reach the train station and the catchment is ‘completely anisotropic’. A station is not necessarily located at the centre of its catchment area, and the above compactness measure did take this into consideration. The compactness was also calculated for each segmentation variable (i.e. age, gender, trip direction and travel mode) for each station. The results of the compactness analysis for the seven stations in the case study are presented in Section 4.
Designing freight traffic analysis zones for metropolitan areas: identification of optimal scale for macro-level freight travel analysis
Published in Transportation Planning and Technology, 2020
Prasanta K. Sahu, Aitichya Chandra, Agnivesh Pani, Bandhan Bandhu Majumdar
The average compactness in the shape of a zone system can be measured in terms of a shape index. The reason for using the shape index as a compactness measure is that it is independent of zone size (Guo and Aultman-Hall 2014). The computation of the shape index involves the area and perimeter of a zone and a perfect compact shape will have a shape index of 1. The shape index value will increase for more compact shapes. The shape index (SI) for a zone system is given by:where n is the number of zones in a zone system and is the perimeter of the ith zone, and is the area of the ith zone.