SPATIAL SYNTAX AS A TOOL FOR STUDYING THE STRUCTURE AND CONFIGURATION OF PUBLIC SPACES

The author presents the theory of spatial syntax, which is a key tool for under-standing of the structure of public space and its configuration. Spatial decisions are determining factors influencing to the behavioral characteristics of people who use public space. The author traces the use of spatial syntax as a tool for choosing a de-sign solution for the reconstruction of Trafalgar Square in London. The main interest of spatial syntax is finding the relationship between human needs and spaces. It is believed that behavioral characteristics are already embedded in the structure of spa-tial systems. Spatial syntax calls this relative characteristic of space as a configura-tion and offers the idea that it is this characteristic that shapes human behavior and thus contains social knowledge. Bill Hiller described the method of analysis of the existing scheme of use of the space of Trafalgar Square and around it, which was taken into account later by the authors of the reconstruction project. The perfect spatial design was to contain three key elements: simple, straight routes for pedestrians, which should cross the space in the middle, not at its edges; the presence of points of perception in several visual areas; availability of facilities for eating, drinking or recreation, located near the main walking routes. The analysis of Trafalgar Square showed that none of these elements was pre-sent in the decision of the square. Spatial analysis helped to find optimal design solu-tions. Spatial analysis of Trafalgar Square has shown that, although the effects of people movement are important, but not as much as the impact of space configura-tion. As the analysis of the design solution of the public space of Trafalgar Square confirms, a successful project means, first of all, reasonable spatial solutions.

Improving Accuracy in Studying the Interactions of Seismic Waves with Bottom Sediments

The emerging tasks of determining the features of bottom sediments, including the evolution of the seabed, require a significant improvement in the quality of data and methods for their processing. Marine seismic data has traditionally been perceived to be of high quality compared to land data. However, high quality is always a relative characteristic and is determined by the problem being solved. In a detailed study of complex processes, the interaction of waves with bottom sediments, as well as the processes of seabed evolution over short time intervals (not millions of years), we need very high accuracy of observations. If we also need significant volumes of research covering large areas, then a significant revision of questions about the quality of observations and methods of processing is required to improve the quality of data. The article provides an example of data obtained during high-precision marine surveys and containing a wide frequency range from hundreds of hertz to kilohertz. It is shown that these data, visually having a very high quality, have variations in wavelets at all analyzed frequencies. The corresponding variations reach tens of percent. The use of the method of factor decomposition in the spectral domain made it possible to significantly improve the quality of the data, reducing the variability of wavelets by several times.

Probabilistic Prediction of Strength and Fracture Toughness Scatters for Ceramics Using Normal Distribution

Tensile strength ft and fracture toughness KIC of ceramic are not deterministic properties or fixed values, but fluctuate within certain ranges. A nonlinear elastic fracture mechanics model was developed in this study and combined with the common normal distribution to predict ceramic’s ft and KIC with consideration of their scatters in a statistical sense. In the model, the relative characteristic crack size a*ch/G (characteristic crack size a*ch, average grain size G) was determined based on the fracture measurements on five types of ceramics with different G from 2 to 20 μm in the reference (Usami S, et al., Eng. Fract Mech. 1986, 23, 745). The combined application of the model and normal distribution has two functions: (i) probabilistic ft and KIC can be derived from seemingly randomly varied fracture tests on small ceramic specimens containing different initial defects/cracks, and (ii) with ft or KIC values (corresponding mean and standard deviation), fracture strength of heterogeneous samples with and without cracks can be predicted by considering scatter described by specified reliability. For the fine ceramics, the predicted results containing the mean and the upper and lower bounds with 96% reliability gained with the model, match very well with the experimental results (a, σN).

Reference-Free Displacement Estimation of Bridges Using Kalman Filter-Based Multimetric Data Fusion

Displacement responses of a bridge as a result of external loadings provide crucial information regarding structural integrity and current conditions. Due to the relative characteristic of displacement, the conventional measurement approach requires reference points to firmly install the transducers, while the points are often unavailable for bridges. In this paper, a displacement estimation approach using Kalman filter-based data fusion is proposed to provide a practical means for displacement measurement. The proposed method enables accurate displacement estimation by optimally utilizing acceleration and strain in combination that have high availability and are free from reference points for sensor installation. The Kalman filter is formulated using a state-space model representing the double integration of acceleration and model-based strain-displacement relationship. The validation of the proposed method is conducted successfully by a numerical simulation and a field experiment, which shows the efficacy and accuracy of the proposed approach in bridge displacement measurement.

Dynamics of the flood response to slow-fast landscape-climate feedbacks

The dynamical evolution of the flood response to landscape-climate feedbacks is evaluated in a joint nonlinear statistical-dynamical approach. For that purpose, a spatiotemporal sensitivity analysis is conducted on hydrological data from 1976–2008 over 804 catchments throughout Austria, and a general, data-independent nonlinear dynamical model is built linking floods with climate (via precipitation), landscape (via elevation) and their feedbacks. These involve nonlinear scale interactions, with landform evolution processes taking place at the millennial scale (slow dynamics), and climate adjusting in years to decades (fast dynamics). The results show that floods are more responsive to spatial (regional) than to temporal (decadal) variability. Catchments from dry lowlands and high wetlands exhibit similarity between the spatial and temporal sensitivities (spatiotemporal symmetry) and low landscape-climate codependence, suggesting they are not coevolving significantly. However, intermediate regions show differences between those sensitivities (symmetry breaks) and higher landscape-climate codependence, suggesting undergoing coevolution. The break of symmetry is an emergent behaviour from nonlinear feedbacks within the system. A new coevolution index is introduced relating spatiotemporal symmetry with relative characteristic celerities, which need to be taken into account in hydrological space-time trading. Coevolution is expressed here by the interplay between slow and fast dynamics, represented respectively by spatial and temporal characteristics. The dynamical model captures emerging features of the flood dynamics and nonlinear landscape-climate feedbacks, supporting the nonlinear statistical assessment of spatiotemporally asymmetric flood change. Moreover, it enables the dynamical estimation of flood changes in space and time from the given knowledge at different spatiotemporal conditions. This study ultimately brings to light emerging signatures of change in floods arising from nonlinear slow-fast feedbacks in the landscape-climate dynamics, and contributes towards a better understanding of spatiotemporal flood changes and underlying nonlinearly interacting drivers.

Simulation of Engineering Structure’s Fluctuating Wind Velocity Based on the Linear Filter Method

In the wind velocity simulation of large-span structure, it need to consider the relative characteristic of time and spatial in the same time. Based on the linear filter method, the program is design to simulate the spatial multi-nodes wind velocity time-history curve. The influence of different parameter value to simulation result is discussed. The parameter value is determined to the large-span structure simulation.