Sector search strategies for odor trail tracking

Ants, mice, and dogs often use surface-bound scent trails to establish navigation routes or to find food and mates, yet their tracking strategies remain poorly understood. Chemotaxis-based strategies cannot explain casting, a characteristic sequence of wide oscillations with increasing amplitude performed upon sustained loss of contact with the trail. We propose that tracking animals have an intrinsic, geometric notion of continuity, allowing them to exploit past contacts with the trail to form an estimate of where it is headed. This estimate and its uncertainty form an angular sector, and the emergent search patterns resemble a “sector search.” Reinforcement learning agents trained to execute a sector search recapitulate the various phases of experimentally observed tracking behavior. We use ideas from polymer physics to formulate a statistical description of trails and show that search geometry imposes basic limits on how quickly animals can track trails. By formulating trail tracking as a Bellman-type sequential optimization problem, we quantify the geometric elements of optimal sector search strategy, effectively explaining why and when casting is necessary. We propose a set of experiments to infer how tracking animals acquire, integrate, and respond to past information on the tracked trail. More generally, we define navigational strategies relevant for animals and biomimetic robots and formulate trail tracking as a behavioral paradigm for learning, memory, and planning.

Structural and thermodynamic properties of inhomogeneous fluids in rectangular corrugated nano-pores

Based on free-energy average method, an area-weighted effective potential is derived for rectangular corrugated nano-pore. With the obtained potential, classical density functional theory is employed to investigate the structural and thermodynamic properties of confined Lennard-Jones fluid in rectangular corrugated slit pores. Firstly, influence of pore geometry on the adsorptive potential is calculated and analyzed. Further, thermodynamic properties, including excess adsorption, solvation force, surface free energy and thermodynamic response functions are systematically investigated. It is found that pore geometry can largely modulate the structure of the confined fluids, which in turn influences other thermodynamic properties. In addition, the results show that different geometric elements have different influences on the confined fluids. The work provides an effective route to investigate the effect of roughness on confined fluids. It is expected to shed light on further understanding about interfacial phenomena near rough walls, and then provide useful clues for design and characterization of novel materials.

Operating Speed Prediction Models for Tangent Segments: A Brief Review

This paper provides a review of studies aimed at developing operating speed prediction models for road tangent sections. The review included many studies, conducted in different geographical areas of the world, in terms of road classification, types of vehicles, techniques and devices used in data collection, number of study sites, the principle adopted in extracting the free-flow speed, as well as the topography that the road path passes through and grads of the studied sections. Moreover, this review mentioned the analysis methods adopted in the modeling, and included the model formulas that the researchers have reached in their studies, as it showed all the geometric elements and traffic characteristics that appeared in the models as independent variables. The author has avoided critiquing or evaluating the methodologies of the reviewed research and accordingly this paper has been prepared for documentation only. The author aims primarily to save the effort and time of graduate students and researchers interested in modeling the operating speed on straight segments, as all data and information are arranged in tables and coordinated for this purpose. Doi: 10.28991/cej-2021-03091784 Full Text: PDF

Perspective/Discussion on “Quantum Mechanical Metric for Internal Cohesion in Cement Crystals” by C. C. Dharmawardhana, A. Misra and Wai-Yim Ching

The single most important structural material, and the major Portland cement binding phase in application globally, is calcium silicate hydrate (C-S-H). The concentration has increasingly changed due to its atomic level comprehension because of the chemistry and complex structures of internal C-S-H cohesion in cement crystals at different lengths. This perspective aimed at describing on calcium-silicate-hydrates (C-S-H) structures with differing contents of Ca/Si ratio based on the report entitled “Quantum mechanical metric for internal cohesion in cement crystals” published by C. C. Dharmawardhana, A. Misra and Wai-Yim Ching. Crystal structural and bond behaviors in synthesized C-S-H were also discussed. The investigator studied large subset electronic structures and bonding of the common C-S-H minerals. From each bonding type, the results and findings show a wide variety of contributions, particularly hydrogen bonding, that allow critical analyses of spectroscopic measurement and constructions of practical C-S-H models. The investigator found that the perfect overall measurement for examining crystal cohesions of the complex substances is the total bond density (TBOD), which needs to be substituted for traditional metrics such as calcium to silicon ratios. In comparison to Tobermorite and Jennite, hardly known orthorhombic phased Suolunites were revealed to have greater cohesion and total order distribution density than those of the hydrated Portland cement backbone. The findings of the perspective showed that utilizing quantum mechanical metrics, the total bond orders and total bond order distributions are the most vital criteria for assessing the crystalline cohesions in C-S-H crystals. These metrics encompass effects of both interatomic interactions and geometric elements. Thus, the total bond order distribution and bond order offer comprehensive and in-depth measures for the overall behaviors of these diverse groups of substances. The total bond order distributions must clearly be substituted for the conventional and longstanding Ca/Si ratios applied in categorizing the cement substances. The inconspicuous Suolunite crystals were found to have the greatest total bond order distributions and the perfect bonding characteristics, compositions, and structures for cement hydrates.

The Influence Of Traffic Control Devices And Road Geometric Characteristics On Traffic Crushes Of Rular Two Lane Road

Traffic accidents worldwide are among the most alarming phenomena because they cost billions of dollars due to death rates and property damage. In Ethiopia, the accident fatality rate is becoming one of the most serious problems. Specifically, in rural highways where in there are problems with traffic control device enforcement and geometric deficiencies. Gedeo zone faces a similar problem that is considered a hot issue on-road crash. This study focused on the influence of traffic control devices and geometric characteristic related to road crashes. The data collection method was a purposive sampling technique considering both primary and secondary data collection system. Direct field observations were conducted, such as field survey and recording of the existing road geometric elements to figure out which geometric element contributory to traffic crashes. The data collected from the police traffic was categorized by clustering the road into different road segments composed of the same geometric characteristics. The severity of the accident analyzed and identified the hazardous road sections (black spot area). The relationships of accident crash established between the influence of traffic control access devices and geometric elements on the crash reduction at the identified accident-prone areas. Further, the study used ANN modeling through engineering software MATLAB to analyze the weight age of crashes on specified road segments concerning geometric road characteristics. Hence, the gradient carriageway width, super-elevation, cross slope, gradient, sight distance number of the horizontal curve, number of vertical curves, and AADT are the major factors for the occurrence of both fatal and injury at the blackspot segment along the rural highway.

CenetBiplot: a new proposal of sparse and orthogonal biplots methods by means of elastic net CSVD

In this work, a new mathematical algorithm for sparse and orthogonal constrained biplots, called CenetBiplots, is proposed. Biplots provide a joint representation of observations and variables of a multidimensional matrix in the same reference system. In this subspace the relationships between them can be interpreted in terms of geometric elements. CenetBiplots projects a matrix onto a low-dimensional space generated simultaneously by sparse and orthogonal principal components. Sparsity is desired to select variables automatically, and orthogonality is necessary to keep the geometrical properties that ensure the biplots graphical interpretation. To this purpose, the present study focuses on two different objectives: 1) the extension of constrained singular value decomposition to incorporate an elastic net sparse constraint (CenetSVD), and 2) the implementation of CenetBiplots using CenetSVD. The usefulness of the proposed methodologies for analysing high-dimensional and low-dimensional matrices is shown. Our method is implemented in R software and available for download from https://github.com/ananieto/SparseCenetMA.

Underway to suprematism: comparative analysis of the works of Kazimir Malevich of 1913–1914

The subject of this research is the works of Kazimir Malevich of the period 1913–1914. Despite numerous scientific works and articles dedicated to the works of K. Malevich, the period of his becoming requires clarification. The object of this research is the Russian avant-garde art of 1913 – 1914. The author dwells on the compositional principles in the painter’s works of this period. Special attention is given to the colorful shapes and geometric elements underlying the compositions of his paintings. Analysis is conducted on the the path of Kazimir Severinovich, the transition from Futurism and Cubo-Futurism through Fevralism to the original style – suprematism. The philosophical and art history analysis in combination with the general scientific methods of research allowed developing a representation on the transformation the artistic pursuits of Kazimir Malevich towards the dominant of the black geometric colorful shape, which subsequently led to the creation of the “Black Square” and the formation of suprematism. The article examines and compares the paintings of the period 1913–1914, when Malevich had moved from being a mentee to creating his own artistic language. The study of the paintings by Kazimir Malevich and determination of large group of works similar in the techniques and colors used allows broadening and complementing the knowledge on the period prior to suprematism.

The dependence of coordinate measurements error of the geometric elements shape characteristics of products on the control points number

The issues of estimating the error of coordinate measurements of the shape characteristics of geometric elements of products depending on the number of control points, taking into account a given confidence probability, are considered. Analytical models are proposed for estimating the error based on a priori data, similar to estimating uncertainty by type B. The correspondence of model and experimental results is verified by the Monte Carlo method using a specially developed program in VBA and the library functions of the Statistical Analysis package of the Microsoft Excel program. Such a characteristic of the shape of the part as roundness is investigated. The influence of the parameters of regular structures associated with the features of the technological processes of manufacturing the part on the parameters of the distribution function of the coordinates of the control points is revealed. Fourier analysis is used to identify and quantify regular structures on the surface of the part. The sources of error that have a significant impact on the results of measurements of the shape characteristics of geometric elements of products are given. Based on the results of statistical calculations, the dependence of the measurement error of the shape characteristics on the number of control points is analyzed, the scope of application of analytical formulas for estimating the error of single measurements for a given confidence probability is determined. The article is intended for specialists in the field of practical coordinate metrology and related fields.

AERODYNAMIC ANALYSIS OF THE CLARK YH AIRFOIL

The analysis of the performance of aerodynamic airfoils leads to optimized approaches regarding the pre-design of fixed and rotating lifting surfaces, with implications on the global characteristics and performances of aircraft. The 2D aerodynamics of the airfoils provides indications on the aeromechanical behavior of the selected geometric elements, which may come as constructive solutions depending on the typology of the missions and the initial requirements of the project. The article provides a scrutiny of and certain educational perspectives on the Clark YH profile analysis, using freeware tools (Javafoil, Profiles and XFLR5).