Kinds Of Spatial Distributions Research Articles

The effects of communication topology on mixed traffic flow: modelling and analysis

This paper aims to evaluate the combined impact of the communication topology (CT) and vehicular spatial distribution (SD) on mixed traffic of human-driven vehicles (HDVs) and connected and autonomous vehicles (CAVs). A generalized car-following (CF) model is presented to capture mixed traffic dynamics, integrating the effects of the CT, human reaction time, information delay and the optimal velocity changes with memory. Then, the linear stable condition of the model is derived using the perturbation method. Finally, extensive simulations are conducted under different CTs (i.e., multiple-predecessor leader following (MPLF) topology, predecessor following (PF) topology, and predecessor-leader following (PLF) topology) and six kinds of SDs. The results reveal that the MPLF topology demonstrates the best steady performance (i.e., stability) and dynamic performance (i.e., smoothness), and that the SD where CAVs are concentrated at the front of the traffic flow shows superior dynamic performance.

Adaptive spatial partition learning for image classification

Spatial Pyramid Matching is a successful extension of bag-of-feature model to embed spatial information of local features, in which the image is divided into a sequence of increasingly finer girds, and the grids are taken as uniform spatial partitions in ad-hoc manner without any theoretical motivation. Obviously, the uniform spatial partition cannot adapt to different spatial distribution across image categories. To this end, we propose a data-driven approach to adaptively learn the discriminative spatial partitions corresponding to each class, and explore them for image classification. First, a set of over-complete spatial partitions covering kinds of spatial distribution of local features are created in a flexible manner, and we concatenate the feature representations of each partitioned region. Then we adopt a discriminative learning formulation with the group sparse constraint to find a sparse mapping from the feature representation to the label space. To further enhance the robustness of the model, we compress the feature representation by removing the dimensions corresponding to those unimportant partitioned regions, and explore the compressed representation to generate a multi-region matching kernel prepared to train a one-versus-others SVM classifier. The experiments on three object datasets (i.e. Caltech-101, Caltech-256, Pascal VOC 2007), and one scene dataset (i.e. 15-Scenes) demonstrate the effectiveness of our proposed method.

Craft data mapping and spatial analysis for historical landscape modeling

Abstract This paper discusses research on gypsum decorated ceilings of Piemonte. They are a precious architectural and rural cultural heritage and are extremely delicate and fragile due to the material characteristics. Some examples of these ceilings date as far back as the late16th century and the earliest examples were made near the end of the 19th century. Apparently similar to wooden coffered ceilings, the gypsum panels in these ceilings have a bearing function together with the wooden framework and they present a very rich collection of decorations derived from the wood carving tradition. The issues on which this paper focuses are the analyses carried out by GIS data management, intended to improve our knowledge of the value of these ceilings. New information about their presence, state of conservation and reasons for their widespread occurrence are the basic pillars for planning possible conservation strategies. A first step in the analysis addresses the comparison of the similarities between ceiling decoration and certain traditional works of wood crafts found in the same area. The collection of data concerning the carved decoration of wooden doors between the 16th and the 19th centuries, together with the organization of a geo-referenced spatial database, has provided the opportunity to identify the presence of gypsum ceilings and carved doors in the same places and belonging to the same period. A second step deals with the meaning of these different kinds of spatial distributions. The generation of different kinds of data clusters, based on the repeated elements on the decorations has been researched. Spatial analyses based on average distances, weighted overlay analysis and involving the digital terrain model of the general area have been performed in order to compare ceiling distributions based on decoration similarities and the historical road network.

SPATIAL DISTRIBUTION OF ELECTRON ENERGY IN THIN FILM ELECTROLUMINESCENT DEVICES

We adopted an analytical approach based on fitting of the full band structure of ZnS by polynomials.We studied the electron transport process in phosphor layer of thin-film electroluminescent divices by Monte Carlo Simulation.Two kinds of spatial distributions of electron energy are obtained in phosphor layers of the sandwich structure and the layered optimization structure,and the explanation about it is also given.

ON THE ORIGIN AND PERSISTENCE OF ERROR IN GEOGRAPHY

ABSTRACT Human error concerning the geography of the earth has been recurrent throughout historic time. Some kinds of error arise because of the problems of dealing with phenomena in the three-dimensional zone forming earth-space. The broad curvature of the earth, the sheer diversity of earth-space, and the patterns of change through time all form pitfalls for the geographer who is, thereby, liable to error in his descriptive analyses. The problems of placing percepts (things perceived) against concepts (mental abstractions) make for difficulties in analyzing the three-dimensional spatial zone in which geographers work. Among the kinds of error committed there are avoidable varieties, such as the inexact use of descriptive and analytical language, the uncritical use of statistical data, the acceptance of unreliable data, and the confusion of the several kinds of spatial distributions. Less avoidable error derives from the formulation of hypotheses accounting for phenomena which, when critically examined a...

Annals of the Association of American Geographers

Human error concerning the geography of the earth has been recurrent throughout historic time. Some kinds of error arise because of the problems of dealing with phenomena in the three-dimensional zone forming earth-space. The broad curvature of the earth, the sheer diversity of earth-space, and the patterns of change through time all form pitfalls for the geographer who is, thereby, liable to error in his descriptive analyses. The problems of placing percepts (things perceived) against concepts (mental abstractions) make for difficulties in analyzing the three-dimensional spatial zone in which geographers work. Among the kinds of error committed there are avoidable varieties, such as the inexact use of descriptive and analytical language, the uncritical use of statistical data, the acceptance of unreliable data, and the confusion of the several kinds of spatial distributions. Less avoidable error derives from the formulation of hypotheses accounting for phenomena which, when critically examined against accurate data, turn out to be inadequate, incomplete, or wrong. Such early hypotheses may actually become stimulants to progress in research; the Huttonian theory of the observable causation for landforms in time produced all of modern landform theory while at the same time producing many errors in analytical explanation. The construct of a model, per conceptualization, risks dangers of obscuring effective explanation owing to the fact that models normally can originally be only caricatures of reality. The Davisian cycle of erosion so obscured progress for a long period by its overacceptance. Social Darwinism, similarly, obstructed effective explanation for a period. The persistence of error becomes an obstruction to progress in geography. The overlong employment of Maury's simple model of the earth's wind systems was such a persistence. Currently the dichotomy of the dualism phrased as physical geography and human geography constitutes an error of persistence. The elimination of avoidable error and the replacement of inadequate to erring hypotheses require a continuing process of critical review, lest avoidable error continue into persistent error. However, on the present errors of inadequate hypotheses may be built the progress of geography in the future. THIS essay offers some thoughts on the origin and persistence of error in geography. Received for publication August 19, 1966. 1 Address given by the Honorary President of the Association of American Geographers at its 62nd Annual Meeting, Toronto, Ontario, Canada, August 31, 1966. Not that geographers have contributed more than their share of error to the unfolding of man's comprehension of the universe. -In all fields of learning, as Joseph Jastrow pointed out, the rare flashes of intuitive judgment illuminate man's slow progress through quagmires of ignorance, thickets of superstition,