Effects Of Spatial Constraints Research Articles

Effects of spatial constraints and ages on children’s upper limb performance in mid-air gesture interaction

Through two controlled experiments, including a pie menu study and a target acquisition study, this paper investigates children’s performance on mid-air gesture interactions in different spatial constraints (i.e., in different orientations/distances), as well as the age effect on such interaction scenarios. The first experiment recorded children’s speeds and accuracies following certain directions under menus with different numbers of items, while the second evaluated the speed–accuracy trade-off (SAT) of children’s arm movements. We also compared performance differences between two age-related groups (i.e., 6–8 years old and 9–12 years old). Based on these experiments, we propose an improved design for UI menus based on mid-air gesture interaction for children. The improved design provides suggestions for setting appropriate directions and difficulty indexes, which makes it much easier and quicker for children to use the menus with mid-air interaction.

Compositional Proteomics: Effects of Spatial Constraints on Protein Quantification Utilizing Isobaric Tags.

Mass spectrometry (MS) has become an accessible tool for whole proteome quantitation with the ability to characterize protein expression across thousands of proteins within a single experiment. A subset of MS quantification methods (e.g., SILAC and label-free) monitor the relative intensity of intact peptides, where thousands of measurements can be made from a single mass spectrum. An alternative approach, isobaric labeling, enables precise quantification of multiple samples simultaneously through unique and sample specific mass reporter ions. Consequently, in a single scan, the quantitative signal comes from a limited number of spectral features (≤11). The signal observed for these features is constrained by automatic gain control, forcing codependence of concurrent signals. The study of constrained outcomes primarily belongs to the field of compositional data analysis. We show experimentally that isobaric tag proteomics data are inherently compositional and highlight the implications for data analysis and interpretation. We present a new statistical model and accompanying software that improves estimation accuracy and the ability to detect changes in protein abundance. Finally, we demonstrate a unique compositional effect on proteins with infinite changes. We conclude that many infinite changes will appear small and that the magnitude of these estimates is highly dependent on experimental design.

The topology of urban road networks and its role to urban mobility

Abstract This article studies how the topology of Urban Road Networks (URNs) is linked with socioeconomic aspects of their urban systems, aiming in revealing patterns that are related to urban mobility. The rationale of the study is based on the consideration that both the structure of urban networks and the conduct of urban mobility are controlled by complex mechanisms, where a primary driving factor affecting, either directly or indirectly, their planning, evolution and development is the existence of spatial constraints. The analysis examines how some fundamental network measures of global URNs studied in literature are related to socioeconomic indices and focuses on the case study of four URNs of the region of Thessaly, in Greece, where their socioeconomic framework is familiar. Overall, the analysis provides interesting insights about the effects of spatial constraints on the network topology, the magnitude of the examined URNs comparatively to global cases, the growth patterns between connectivity and distance and about how the network topology is related to urban mobility, population and market information.

Urban mobility under the complex network perspective: a case study of the urban road networks of Thessaly, Greece

This article studies the topology of four urban road networks (URNs) in the region of Thessaly, Greece, comparatively with some aspects of their socioeconomic environment. The purpose of the study is to enlighten the interrelation between network structure and traffic, as defined in the case of URNs submitted to spatial constraints, and to reveal the topological patterns describing the concept of urban mobility. The methodological approach examines whether some fundamental measures of complex network analysis are related to socioeconomic indices of urban mobility in the socioeconomic framework of the URNs of Thessaly. Overall, the analysis provides interesting insights about the effects of spatial constraints on the network topology, the magnitude of the examined URNs comparatively with global cases, the growth patterns between connectivity and distance, and how the network topology is related to urban mobility, population, and market information.

Effects of Spatial Constraints and Brønsted Acid Site Locations on para‐Terphenyl Ionization and Charge Transfer in Zeolites

The locations of Brønsted acid sites (BAS) in the channels of medium-pore zeolites have a significant effect on the spontaneous ionization of para-terphenyl (PP(3)) insofar as spatial constraints determine the stability of transition states and charge-transfer complexes relevant to charge separation. The ionization rates and ionization yield values demonstrate that a strong synergy exists between the H(+) polarization energy and spatial constraints imposed by the channel topology. Spectroscopic and modeling results show that PP(3) incorporation, charge separation, charge transfer and charge recombination differ dramatically among zeolites with respect to channel structure (H-FER, H-MFI, H-MOR) and BAS density in the channel. Compartmentalization of ejected electrons away from the initial site of ionization decreases dramatically the propensity for charge recombination. The main mode of PP(3)(.+) decay is hole transfer to form AlO(4)H(.+) ⋅⋅⋅PP(3) charge-transfer complexes characterized by intense absorption in the visible range. According to the nonadiabatic electron-transfer theory, the small reorganization energy in constrained channels explains the slow hole-transfer rate.

ON THE EFFECTS OF GEOGRAPHICAL CONSTRAINTS ON TASK EXECUTION IN COMPLEX NETWORKS

In the present work, the effects of spatial constraints on the efficiency of task execution in systems underlain by geographical complex networks are investigated, where the probability of connection decreases with the distance between the nodes. The investigation considers several configurations of the parameters defining the network connectivity, and the Barabási–Albert network model is also considered for comparisons. The results show that the effect of connectivity is significant only for shorter tasks, the locality of connections implied by the spatial constraints reduces efficiency, and the addition of edges can improve the efficiency of the execution, although with increasing locality of the connections the improvement is small.

Effects of Spatial Constraints on Trunk Kinematics during a Dependent Transfer on an Aircraft

A concern related to air travel by people with disabilities is the risk of low-back injuries while transferring the traveler to or from the aircraft seat. Potential contributing factors to this risk are the spatial constraints imposed by the aircraft's interior. This study investigated the effects of such constraints on the trunk angles, angular velocities, and load moment arm during a two-person dependent transfer between a wheelchair and an aircraft seat. Trunk kinematics were recorded as 33 pairs of subjects transferred a dummy to and from an aircraft seat under unconstrained and constrained conditions. The constraints primarily affected the front transferor, increasing peak trunk flexion, lateral bending, twisting, and load moment arm. Effects on the rear transferor were small and appeared to have offsetting effects on injury risk. The results suggest that the row spacing on an aircraft contributes to low-back injury risk during dependent transfers of travelers with disabilities.

The effects of spatial constraints on the evolution of weighted complex networks

Motivated by the empirical analysis of the air transportation system, we define a networkmodel that includes geographical attributes along with topological and weight (traffic)properties. The introduction of geographical attributes is made by constraining thenetwork in real space. Interestingly, the inclusion of geometrical features inducesnon-trivial correlations between the weights, the connectivity pattern and theactual spatial distances of vertices. The model also recovers the emergence ofanomalous fluctuations in the betweenness-degree correlation function as first observedby Guimerà and Amaral (2004 Eur. Phys. J. B 38 381). The presented resultssuggest that the interplay between weight dynamics and spatial constraints is a keyingredient in order to understand the formation of real-world weighted networks.

Variability of reciprocal aiming movements during standing: The effect of amplitude and frequency

This study investigated the variability of the center of pressure (COP) trajectory during voluntary whole-body oscillations. While standing upright on a force platform, eight subjects leaned forward and backward so as to perform reciprocal aiming movements with their COP at a prescribed frequency (F) and amplitude (A) using online visual feedback of their COP location. A total of 25 F-A combinations were tested for each subject (3 < A < 9 cm, and 0.35 < F < 1.35 Hz). Spatial and temporal variability of the COP was assessed by computing the standard deviation (SD) and coefficient of variation (CV) of the amplitude (trough to peak) and frequency (peak to peak) of the COP cycles within each trial, respectively. The results revealed that all variability indices depended on the prescribed F and A. Concerning the effect of spatial constraints on spatial variability, SD spatial increased as a function of A, while CV spatial decreased as function of A. A similar pattern was observed with respect to the effect of temporal constraints on temporal variability (SD temporal increased as a function of F, while CV temporal decreased). As for "cross-over" effects, there was an effect of F on spatial variability, such that SD spatial and CV spatial were minimal at 0.6 Hz. For the "cross over" effect of A on temporal variability, both SD spatial and CV spatial decreased as a function of A. Across the experimental conditions, there were weak or no correlations between variability in the time and space domain. Comparisons with an earlier study on human gait (Danion F, Varraine E, Bonnard M, Pailhous J. Stride variability in human gait: the effect of stride frequency and stride length. Gait Posture 2003;18:69-77) suggest that the effects of spatial constraints are relatively task independent, whereas the effects of temporal constraints depend on the nature of the motor task that is performed.

Small “Magnetic” Clusters of Ga and In with As and V

ABSTRACTSeveral small clusters of Ga and In with As and V atoms are pre-designed to study effects of spatial constraints on electronic and magnetic properties of such clusters by means of the Hartree-Fock (HF) method. The obtained electronic energy level structures (ELSs), optical transition energies (OTEs) and spin densities of these clusters are compared to those specific to the corresponding clusters nucleated without spatial constraints. The pre-designed indium-based clusters demonstrate the enhanced spin densities as compared to those of the gallium-based clusters with equal numbers of V atoms, and thus can be of interest for applications in spintronic and magneto-optic memory materials development.

The Effects of Spatial Constraints on the Legibility of Handwritten Alphanumeric Codes

Abstract Lists of typewritten alphanumeric codes were copied by hand into one of three spatial arrays typical of those employed in the preparation of information for computer analysis. The resulting manuscripts were then checked for accuracy by another group of subjects. It was found that arrays of blank lines gave faster performance, both copying and checking than arrays of small boxes where each alphanumeric character was written in a separate box. However, both copying and checking was faster with arrays of boxes than with arrays in which each alphanumeric character was separated by a small rising mark. These findings were consistent with those of Barnard and Wright (1976) who used familiar names instead of codes. Therefore the deleterious effects of these spatial constraints seem to have wide generality across different materials.