scholarly journals A Multilevel Road Alignment Model for Spatial-Query-by-Sketch

2020 ◽  
Vol 10 (21) ◽  
pp. 7685
Author(s):  
Ming Tang ◽  
Zoe Falomir ◽  
Yehua Sheng
Keyword(s):  
Spatial Relationship ◽  
Experimental Results ◽  
Spatial Query ◽  
Specific Location ◽  
Sketch Maps ◽  
Road Maps ◽  
Alignment Model ◽  
Sketch Map

A sketch map represents an individual’s perception of a specific location. However, the information in sketch maps is often distorted and incomplete. Nevertheless, the main roads of a given location often exhibit considerable similarities between the sketch maps and metric maps. In this work, a shape-based approach was outlined to align roads in the sketch maps and metric maps. Specifically, the shapes of main roads were compared and analyzed quantitatively and qualitatively in three levels pertaining to an individual road, composite road, and road scene. An experiment was performed in which for eight out of nine maps sketched by our participants, accurate road maps could be obtained automatically taking as input the sketch and the metric map. The experimental results indicate that accurate matches can be obtained when the proposed road alignment approach Shape-based Spatial-Query-by-Sketch (SSQbS) is applied to incomplete or distorted roads present in sketch maps and even to roads with an inconsistent spatial relationship with the roads in the metric maps. Moreover, highly similar matches can be obtained for sketches involving fewer roads.

scholarly journals Unsupervised Sub-tree Alignment for Tree-to-Tree Translation

2013 ◽  
Vol 48 ◽  
pp. 733-782 ◽  
Author(s):  
T. Xiao ◽  
J. Zhu
Keyword(s):  
Machine Translation ◽  
State Of The Art ◽  
Experimental Results ◽  
Alignment Accuracy ◽  
Syntactic Structures ◽  
Tree Alignment ◽  
Matrix Encoding ◽  
Word Alignments ◽  
Alignment Model ◽  
Translation Systems

This article presents a probabilistic sub-tree alignment model and its application to tree-to-tree machine translation. Unlike previous work, we do not resort to surface heuristics or expensive annotated data, but instead derive an unsupervised model to infer the syntactic correspondence between two languages. More importantly, the developed model is syntactically-motivated and does not rely on word alignments. As a by-product, our model outputs a sub-tree alignment matrix encoding a large number of diverse alignments between syntactic structures, from which machine translation systems can efficiently extract translation rules that are often filtered out due to the errors in 1-best alignment. Experimental results show that the proposed approach outperforms three state-of-the-art baseline approaches in both alignment accuracy and grammar quality. When applied to machine translation, our approach yields a +1.0 BLEU improvement and a -0.9 TER reduction on the NIST machine translation evaluation corpora. With tree binarization and fuzzy decoding, it even outperforms a state-of-the-art hierarchical phrase-based system.

Ordering

2015 ◽  
pp. 586-598
Author(s):  
Sahib Jan ◽  
Angela Schwering ◽  
Jia Wang ◽  
Malumbo Chipofya
Keyword(s):  
Spatial Information ◽  
Empirical Work ◽  
Computational Approach ◽  
Cognitive Effects ◽  
Constraint Networks ◽  
Spatial Objects ◽  
Sketch Maps ◽  
Map Alignment ◽  
Street Segments ◽  
Sketch Map

Sketch maps are externalizations of cognitive maps which are typically distorted, schematized, incomplete, and generalized. Processing spatial information from sketch maps automatically requires reliable formalizations which are not subject to schematization, distortion or other cognitive effects in sketch maps. Based on previous empirical work, the authors identified different sketch aspects such as ordering, topology and orientation to align and integrate spatial information from sketch maps with metric maps qualitatively. This research addresses the question how these qualitative sketch aspects can be formalized for a computational approach for sketch map alignment. In this study, the authors focus on the ordering aspect: ordering of landmarks and street segments along routes and around junctions. The authors first investigate different qualitative representations and propose suitable representations to formalize these aspects. The proposed representations capture qualitative relations between spatial objects in the form of qualitative constraint networks. The authors then evaluate the proposed representations by testing the accuracy of qualitative constraints between sketched objects and their corresponding objects in a metric map. The results of the evaluation show that the proposed representations are suitable for the alignment of spatial objects from sketch maps with metric maps.

scholarly journals An Improved Ball Pivot Algorithm-Based Ground Filtering Mechanism for LiDAR Data

2019 ◽  
Vol 11 (10) ◽  
pp. 1179 ◽  
Author(s):  
Wei Ma ◽  
Qingquan Li
Keyword(s):  
Spatial Relationship ◽  
Single Layer ◽  
Experimental Results ◽  
Lidar Data ◽  
Initial Surface ◽  
Seed Point ◽  
Pivot Algorithm ◽  
Group Iii ◽  
Digital Elevation ◽  
Elevation Model

Automatic ground filtering is an essential step for Digital Elevation Model (DEM) generation, which has significant application value. However, extraction and classification of ground points from the Light Detection and Ranging (LiDAR) data, especially in multitudinous terrain situations, is a challenging task because it is difficult to determine the set of optimal parameters for removing various non-ground features. In this paper, a new ground filtering technique based on an improved Ball Pivot Algorithm (BPA) is proposed. At the beginning, the LiDAR point cloud dataset was divided into different subsets based on the 2D regular grid. The lowest point in each grid was selected as the seed point to build a single-layer surface. After that, the improved BPA was executed to remove points on the higher location. Then, the rest of the points were calculated and selected as a new seed point according to the spatial relationship with the initial surface. Finally, non-ground points were filtered by means of improved BPA traversing all the grids. Our experimental results on the Benchmark dataset provided by the International Society for Photogrammetry and Remote Sensing (ISPRS) Working Group III/3 showed high accuracy (with a mean kappa coefficient over 80%) in terms of completeness, correctness, and quality for DEM generation. The experimental results demonstrated the proposed method is robust to various terrain situations, as it is more effective and feasible for ground filtering.

An Empirical Study on Pertinent Aspects of Sketch Maps for Navigation

2013 ◽  
Vol 7 (4) ◽  
pp. 26-43 ◽  
Author(s):  
Jia Wang ◽  
Rui Li
Keyword(s):  
Cognitive Maps ◽  
Spatial Relations ◽  
Qualitative Reasoning ◽  
Spatial Thinking ◽  
Navigation Systems ◽  
Spatial Awareness ◽  
Sequential Order ◽  
Spatial Objects ◽  
Sketch Maps ◽  
Sketch Map

Navigation systems which employ sequence-based directions have been found not effective in facilitating the spatial ability for humans to be aware of themselves in an environment. Traditional maps are found easily conveying the configuration of spatial objects but having difficulty to facilitate the correspondence to spatial objects in the real world. Sketch maps as schematic map-like representations have been suggested being a possible way of achieving goals of facilitating both navigation and spatial awareness. Moreover, sketch maps as externalizations of cognitive maps have been proved as reliable representations for human spatial thinking. In this study, the authors investigate the characteristics of directions given in two different forms: sketch maps and verbal descriptions (turn-by-turn instructions). The investigation addresses three aspects of spatial relations which are orientation, street topology and sequential order and their representations using existing qualitative reasoning calculi. The results of this study demonstrate sketch maps as a better direction-giving method and provide insights of applying sketch-map-like components for navigation.

scholarly journals Hyperspectral image spectral-spatial classification via weighted Laplacian smoothing constraint-based sparse representation

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254362
Author(s):  
Eryang Chen ◽  
Ruichun Chang ◽  
Ke Guo ◽  
Fang Miao ◽  
Kaibo Shi ◽  
...  
Keyword(s):  
Sparse Representation ◽  
Hyperspectral Image ◽  
Matching Pursuit ◽  
Spatial Relationship ◽  
Nearest Neighbors ◽  
Weighting Factor ◽  
Experimental Results ◽  
Spectral Information ◽  
Weighted Laplacian ◽  
Laplacian Smoothing

As a powerful tool in hyperspectral image (HSI) classification, sparse representation has gained much attention in recent years owing to its detailed representation of features. In particular, the results of the joint use of spatial and spectral information has been widely applied to HSI classification. However, dealing with the spatial relationship between pixels is a nontrivial task. This paper proposes a new spatial-spectral combined classification method that considers the boundaries of adjacent features in the HSI. Based on the proposed method, a smoothing-constraint Laplacian vector is constructed, which consists of the interest pixel and its four nearest neighbors through their weighting factor. Then, a novel large-block sparse dictionary is developed for simultaneous orthogonal matching pursuit. Our proposed method can obtain a better accuracy of HSI classification on three real HSI datasets than the existing spectral-spatial HSI classifiers. Finally, the experimental results are presented to verify the effectiveness and superiority of the proposed method.

scholarly journals DEM based Terrain Sketch Mapping in a Loess Landform by considering visual hierarchy and feature generalization

2019 ◽  
Vol 1 ◽  
pp. 1-2
Author(s):  
Yihan Cheng ◽  
Xin Yang ◽  
Hailong Liu
Keyword(s):  
Loess Plateau ◽  
The Loess Plateau ◽  
Perspective View ◽  
Visual Hierarchy ◽  
Feature Lines ◽  
Loess Landform ◽  
Sketch Maps ◽  
Filter Noise ◽  
Terrain Features ◽  
Sketch Map

<p><strong>Abstract.</strong> A terrain sketch map can effectively describe the terrain features and spatial pattern of a landscape, which are sketched with lines by a geographer after recognizing, analyzing and summarizing the features of a terrain scene to present his/her understanding of a landscape (Bao 1956, Chen 1958, Liu 1988). Compared with a digital elevation model (DEM) scene map, a terrain sketch map, as a scientific abstraction and expression of geomorphological features from the perspective view, is characterized by conciseness and profoundness to show the intrinsic features of a landscape. With the rapid development of computer visualization and digital terrain analysis methods, computer-assisted terrain sketches based on DEM may be automatically generated, depending on geographic cognition theory and the sketch description method.</p><p> Previous research has generated terrain scene maps based on DEM data and has produced various styles of terrain maps, i.e. oil painting, ink painting, pen and pencil sketch maps (Visvalingam et al. 1998, Whelan et al. 2003, Way et al. 2006, Bhattacharjee et al. 2008). However, those computer-drawn sketch maps have focused on the artistic effect rather than depicting terrain features and landform structures. Moreover, the area used for sketch mapping in those researches was relatively small, and visual hierarchy was not considered. Thus, those maps differ considerably from hand-drawn sketch maps by geographers or geologists. Therefore, this paper aims to generate terrain sketch map which can express terrain features as well as artistic effect.</p><p> In this study, one loess ridge-hill area (Wuqi) in the loess plateau of China was selected by considering the typicality of the geomorphic types and the availability of data. The 5&amp;thinsp;m resolution DEM data was obtained from the National Administration of Surveying, Mapping and Geoinformation, with an area of 102&amp;thinsp;km<sup>2</sup>.</p><p> Three aspects as terrain features, visual hierarchy and feature generalization were considered in this paper.</p><p> Firstly, the typical terrain features must be presented in the sketch map. The loess shoulder line, bank gully lines and surface flow lines in loess landform area were extracted (Yang et al. 2017, Yang et al. 2018). Then based on the Bresenham algorithm (Bresenham 1965), the visual outlines in perspective view were generated.</p><p> Secondly, the visual hierarchy is considered in this study. In a terrain sketch map, more topographically-detailed information is described in the near view, whereas only the approximate outlines and less topographical information are displayed in the distant view. Therefore, a self-adapted visual hierarchy division method was proposed. The scenes are visually divided into three levels, i.e. near view, medium view and distant view. Different numbers and types of terrain features are assigned to each visual level to obtain the effect of clear near and blurred distant views.</p><p> Thirdly, in complexity terrain area, the scene will not only look staggered and messy, but will also affect topographic recognition even only visual outlines are displayed in distant view. Therefore a method of combining DEM and visual watershed generalization was proposed to simplify the visual outlines in distant view.</p><p> Finally, the terrain sketch map is assessed and verified through a questionnaire survey which includes three specialist experts, seven graduate students and twelve undergraduate students with knowledge in geomorphology or geography.</p><p> The result show that the important feature lines added to the terrain sketch map could effectively help to recognize the typical landform characteristics in the loess plateau of China. The severity of soil erosion by gullies are obviuosly presented (Fig.1d) comparing to the sketch mapping with only visual outlines (Fig1b). The map look messy and unsigtly if all the terrain feature lines were put into the map (Fig.1c). By considering the law of air perspective, the visual hierarchy was divided and the visual outlines in the distant view was generalized, thereby realizing the characteristics of a terrain sketch map clear in near view and blurred in distant view (Fig.1d). It also showed from the questionnaire that DEM resolution influence the performance of our method especially with coarse resolution DEM. The experts suggested that filter noise in near view and generalisation in distant view can be further improved.</p>

scholarly journals Opinion Relation Co-Extraction Based on Partially-Supervised Topical Relations Word Alignment Model

2020 ◽  
Vol 8 (6) ◽  
pp. 135-142
Keyword(s):  
Experimental Results ◽  
Word Alignment ◽  
Ranking Algorithm ◽  
Fine Grained ◽  
Opinion Extraction ◽  
Proposed Model ◽  
On Line ◽  
Alignment Model ◽  
Associated Variable

The most critical tools for fine-grained opinion extraction are opinion goals and opinion terms extracted from on-line comments. The key part of this process is to identify the connection between terms. To do this, the Word Alignment Model (WAM) was introduced in which the associated variable can be identified by word alignment by an opinion goal. Nevertheless, its ability to extract opinion words was less successful. In order to determine opinion connections as a process of alignment, the partially supervised Word Alienation Model (PSWAM) has therefore been created. Then a visual co-ranking algorithm was implemented together with the Opinion Relationship Map, to model all the candidates and to measure the confidence of each voter by defining their opinion. In addition, higher-confidence candidates were extracted as opinions or opinions. This method, though, involves an added kind of interaction with terms such as topical connections in graphic thought. Therefore the current relationship is assumed in this report in order to model the applicants and derive the feelings, views and opinions. The efficiency of co-extracting thoughts, viewpoints and issues is enhanced effectively by using this method. The experimental results further indicate that compared to the existing paradigm, the efficiency of the proposed model.

Electroluminescence imaging of Cu(In,Ga)Se2 thin film modules

2009 ◽  
Vol 1165 ◽  
Author(s):  
Uwe Rau ◽  
Thomas Kirchartz ◽  
Anke Helbig ◽  
Bart Elger Pieters
Keyword(s):  
Thin Film ◽  
Network Model ◽  
Evaluation Method ◽  
Voltage Drop ◽  
Experimental Results ◽  
Specific Location ◽  
Current Voltage ◽  
Electroluminescence Intensity ◽  
Current Voltage Characteristics ◽  
The Individual

AbstractElectroluminescence images gained from Cu(In,Ga)Se2 mini-modules under different voltage bias conditions are investigated. The mini-modules of area 20 × 20 cm2 with 42 cells exhibit typically 10-20 localized shunts. The consequences of these shunts on the performance of the individual cells and of the entire module are analyzed quantitatively by evaluating the electroluminescence images. Our evaluation method uses the fact that the electroluminescence intensity at each position in each cell within the module depends on the actual voltage drop over the junction at this specific location. Thus, the analysis of the electroluminescence intensity allows us to reconstruct the current/voltage characteristics of all individual cells in the module. In addition, we provide first simulations using a distributed diode network model to quantitatively explain the experimental results.

The art of maps

2019 ◽  
pp. 227-239
Author(s):  
Matthew J. Genge
Keyword(s):  
High Resolution ◽  
Geological Mapping ◽  
Geological Maps ◽  
Record Data ◽  
Sketch Maps ◽  
Field Notes ◽  
Sketch Map

Geological maps record the exposure of different rock units at the surface and are crucial in determining the stratigraphy and structure of a region. Creating and interpreting geological maps are important skills for an Earth Scientist. This chapter describes the methods used in geological mapping, including the tactics involved during fieldwork and the conventions and symbols used to record data. The chapter illustrates the use of sketch maps during fieldwork to record high resolution observations in areas with complex geological relationships. Four examples of sketch map are given to demonstrate how they can be used in field notes to record spatially constrained observations.

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