On Self Intersections of Freeform Curves and Surfaces

2008 ◽  
Author(s):  
Gershon Elber
Keyword(s):  
Algebraic Structure ◽  
State Of The Art ◽  
Geometric Design ◽  
The Self ◽  
The Other ◽  
Challenging Problem ◽  
Curves And Surfaces ◽  
Current State ◽  
Art Research ◽  
Surface Intersections

The computations of curve-curve and surface-surface intersections are considered difficult problems in geometric design. Numerous results were annually published on these topics for the last several decades. Moreover, the detection and more so the computation and even elimination of self-intersections in freeform curves and surfaces is viewed by many as a far more challenging problem, with much fewer satisfactory results. In recent years, several methods were developed to robustly detect, compute and even eliminate self intersections in general freeform (typically NURBs) curves and surfaces, exploiting intrinsic and/or geometric properties, on one side, and the algebraic structure of the shape, on the other. Other methods are specific and employ special properties of the problem in hand, as is the case of offset computation. In this work, we will survey some of our results and others, and provide a birds view of the current state-of-the-art research, on the self-intersections problem, in the freeform domain.

Occupant pre-crash kinematics in rotated seat arrangements

2021 ◽  
pp. 095440702110045
Author(s):  
Alexander Diederich ◽  
Christophe Bastien ◽  
Karthikeyan Ekambaram ◽  
Alexis Wilson
Keyword(s):  
State Of The Art ◽  
The Other ◽  
Human Model ◽  
Multi Objective ◽  
Emergency Braking ◽  
Seating Arrangement ◽  
Current State ◽  
Occupant Comfort ◽  
Occupant Kinematics ◽  
Belt System

The introduction of automated L5 driving technologies will revolutionise the design of vehicle interiors and seating configurations, improving occupant comfort and experience. It is foreseen that pre-crash emergency braking and swerving manoeuvres will affect occupant posture, which could lead to an interaction with a deploying airbag. This research addresses the urgent safety need of defining the occupant’s kinematics envelope during that pre-crash phase, considering rotated seat arrangements and different seatbelt configurations. The research used two different sets of volunteer tests experiencing L5 vehicle manoeuvres, based in the first instance on 22 50th percentile fit males wearing a lap-belt (OM4IS), while the other dataset is based on 87 volunteers with a BMI range of 19 to 67 kg/m2 wearing a 3-point belt (UMTRI). Unique biomechanics kinematics corridors were then defined, as a function of belt configuration and vehicle manoeuvre, to calibrate an Active Human Model (AHM) using a multi-objective optimisation coupled with a Correlation and Analysis (CORA) rating. The research improved the AHM omnidirectional kinematics response over current state of the art in a generic lap-belted environment. The AHM was then tested in a rotated seating arrangement under extreme braking, highlighting that maximum lateral and frontal motions are comparable, independent of the belt system, while the asymmetry of the 3-point belt increased the occupant’s motion towards the seatbelt buckle. It was observed that the frontal occupant kinematics decrease by 200 mm compared to a lap-belted configuration. This improved omnidirectional AHM is the first step towards designing safer future L5 vehicle interiors.

scholarly journals Fast Accurate and Automatic Brushstroke Extraction

2021 ◽  
Vol 17 (2) ◽  
pp. 1-24
Author(s):  
Yunfei Fu ◽  
Hongchuan Yu ◽  
Chih-Kuo Yeh ◽  
Tong-Yee Lee ◽  
Jian J. Zhang
Keyword(s):  
Neural Network ◽  
Efficient Algorithm ◽  
Deep Neural Network ◽  
High Efficiency ◽  
State Of The Art ◽  
High Reliability ◽  
The Other ◽  
Manual Annotation ◽  
Stroke Extraction ◽  
Art Research

Brushstrokes are viewed as the artist’s “handwriting” in a painting. In many applications such as style learning and transfer, mimicking painting, and painting authentication, it is highly desired to quantitatively and accurately identify brushstroke characteristics from old masters’ pieces using computer programs. However, due to the nature of hundreds or thousands of intermingling brushstrokes in the painting, it still remains challenging. This article proposes an efficient algorithm for brush Stroke extraction based on a Deep neural network, i.e., DStroke. Compared to the state-of-the-art research, the main merit of the proposed DStroke is to automatically and rapidly extract brushstrokes from a painting without manual annotation, while accurately approximating the real brushstrokes with high reliability. Herein, recovering the faithful soft transitions between brushstrokes is often ignored by the other methods. In fact, the details of brushstrokes in a master piece of painting (e.g., shapes, colors, texture, overlaps) are highly desired by artists since they hold promise to enhance and extend the artists’ powers, just like microscopes extend biologists’ powers. To demonstrate the high efficiency of the proposed DStroke, we perform it on a set of real scans of paintings and a set of synthetic paintings, respectively. Experiments show that the proposed DStroke is noticeably faster and more accurate at identifying and extracting brushstrokes, outperforming the other methods.

Glacially-Triggered Faulting

2021 ◽  
Keyword(s):  
Solid Earth ◽  
State Of The Art ◽  
Ice Sheet ◽  
Northern Europe ◽  
Fault Activity ◽  
Current State ◽  
Investigation Methods ◽  
Art Research ◽  
International Experts ◽  
Fault Scarps

Glacially triggered faulting describes movement of pre-existing faults caused by a combination of tectonic and glacially induced isostatic stresses. The most impressive fault-scarps are found in northern Europe, assumed to be reactivated at the end of the deglaciation. This view has been challenged as new faults have been discovered globally with advanced techniques such as LiDAR, and fault activity dating has shown several phases of reactivation thousands of years after deglaciation ended. This book summarizes the current state-of-the-art research in glacially triggered faulting, discussing the theoretical aspects that explain the presence of glacially induced structures and reviews the geological, geophysical, geodetic and geomorphological investigation methods. Written by a team of international experts, it provides the first global overview of confirmed and proposed glacially induced faults, and provides an outline for modelling these stresses and features. It is a go-to reference for geoscientists and engineers interested in ice sheet-solid Earth interaction.

Qillah: A Morphological Extension for Identifying Plural-of-Paucity Arabic Words

2021 ◽  
pp. 2050013
Author(s):  
Ahlam Fuad ◽  
Amany bin Gahman ◽  
Rasha Alenezy ◽  
Wed Ateeq ◽  
Hend Al-Khalifa
Keyword(s):  
State Of The Art ◽  
The Other ◽  
Rule Based ◽  
Current State ◽  
Maximum Accuracy ◽  
Classical Arabic

Plural of paucity is one type of broken plural used in the classical Arabic. It is used when the number of people or objects ranges from three to 10. Based on our evaluation of four current state-of-the-art Arabic morphological analyzers, there is a lack of identification of broken plural words, specifically the plural of paucity. Therefore, this paper presents “[Formula: see text]” Qillah (paucity), a morphological extension that is built on top of other morphological analyzers and uses a hybrid rule-based and lexicon-based approach to enhance the identification of plural of paucity. Two versions of the Qillah were developed, one is based on FARASA morphological analyzer and the other is based on CALIMA Star analyzer, as these are some of the best-performing morphological analyzers. We designed two experiments to evaluate the effectiveness of our proposed solution based on a collection of 402 different Arabic words. The version based on CALIMA Star achieved a maximum accuracy of 93% in identifying the plural-of-paucity words compared to the baselines. It also achieved a maximum accuracy of 98% compared to the baselines in identifying the plurality of the words.

Generating Predictable and Adaptive Dialog Policies in Single- and Multi-domain Goal-oriented Dialog Systems

2021 ◽  
Vol 15 (04) ◽  
pp. 419-439
Author(s):  
Nhat Le ◽  
A. B. Siddique ◽  
Fuad Jamour ◽  
Samet Oymak ◽  
Vagelis Hristidis
Keyword(s):  
State Of The Art ◽  
Directed Graphs ◽  
Dependency Graph ◽  
The Other ◽  
Middle Ground ◽  
User Characteristics ◽  
Dialog Systems ◽  
Dependency Graphs ◽  
Novel Structure ◽  
Art Research

Most existing commercial goal-oriented chatbots are diagram-based; i.e. they follow a rigid dialog flow to fill the slot values needed to achieve a user’s goal. Diagram-based chatbots are predictable, thus their adoption in commercial settings; however, their lack of flexibility may cause many users to leave the conversation before achieving their goal. On the other hand, state-of-the-art research chatbots use Reinforcement Learning (RL) to generate flexible dialog policies. However, such chatbots can be unpredictable, may violate the intended business constraints, and require large training datasets to produce a mature policy. We propose a framework that achieves a middle ground between the diagram-based and RL-based chatbots: we constrain the space of possible chatbot responses using a novel structure, the chatbot dependency graph, and use RL to dynamically select the best valid responses. Dependency graphs are directed graphs that conveniently express a chatbot’s logic by defining the dependencies among slots: all valid dialog flows are encapsulated in one dependency graph. Our experiments in both single-domain and multi-domain settings show that our framework quickly adapts to user characteristics and achieves up to 23.77% improved success rate compared to a state-of-the-art RL model.

The SLC9A-C Mammalian Na+/H+Exchanger Family: Molecules, Mechanisms, and Physiology

2019 ◽  
Vol 99 (4) ◽  
pp. 2015-2113 ◽  
Author(s):  
S. F. Pedersen ◽  
L. Counillon
Keyword(s):  
State Of The Art ◽  
Expression Profiles ◽  
Tissue Expression ◽  
Gene Organization ◽  
Core Knowledge ◽  
Current State ◽  
Organ Systems ◽  
Evolutionarily Conserved ◽  
Solute Carrier ◽  
Art Research

Na+/H+exchangers play pivotal roles in the control of cell and tissue pH by mediating the electroneutral exchange of Na+and H+across cellular membranes. They belong to an ancient family of highly evolutionarily conserved proteins, and they play essential physiological roles in all phyla. In this review, we focus on the mammalian Na+/H+exchangers (NHEs), the solute carrier (SLC) 9 family. This family of electroneutral transporters constitutes three branches: SLC9A, -B, and -C. Within these, each isoform exhibits distinct tissue expression profiles, regulation, and physiological roles. Some of these transporters are highly studied, with hundreds of original articles, and some are still only rudimentarily understood. In this review, we present and discuss the pioneering original work as well as the current state-of-the-art research on mammalian NHEs. We aim to provide the reader with a comprehensive view of core knowledge and recent insights into each family member, from gene organization over protein structure and regulation to physiological and pathophysiological roles. Particular attention is given to the integrated physiology of NHEs in the main organ systems. We provide several novel analyses and useful overviews, and we pinpoint main remaining enigmas, which we hope will inspire novel research on these highly versatile proteins.

scholarly journals Vectorised Spreading Activation algorithm for centrality measurement

2011 ◽  
Vol 59 (7) ◽  
pp. 469-476 ◽  
Author(s):  
Alexander Troussov ◽  
František Dařena ◽  
Jan Žižka ◽  
Denis Parra ◽  
Peter Brusilovsky
Keyword(s):  
Network Flows ◽  
State Of The Art ◽  
Network Models ◽  
The Other ◽  
Spreading Activation ◽  
Computationally Efficient ◽  
Current State ◽  
Initial Seed ◽  
Spreading Activation Algorithm ◽  
Computationally Efficient Algorithms

Spreading Activation is a family of graph-based algorithms widely used in areas such as information retrieval, epidemic models, and recommender systems. In this paper we introduce a novel Spreading Activation (SA) method that we call Vectorised Spreading Activation (VSA). VSA algorithms, like “traditional” SA algorithms, iteratively propagate the activation from the initially activated set of nodes to the other nodes in a network through outward links. The level of the node’s activation could be used as a centrality measurement in accordance with dynamic model-based view of centrality that focuses on the outcomes for nodes in a network where something is flowing from node to node across the edges. Representing the activation by vectors allows the use of the information about various dimensionalities of the flow and the dynamic of the flow. In this capacity, VSA algorithms can model multitude of complex multidimensional network flows. We present the results of numerical simulations on small synthetic social networks and multi­dimensional network models of folksonomies which show that the results of VSA propagation are more sensitive to the positions of the initial seed and to the community structure of the network than the results produced by traditional SA algorithms. We tentatively conclude that the VSA methods could be instrumental to develop scalable and computationally efficient algorithms which could achieve synergy between computation of centrality indexes with detection of community structures in networks. Based on our preliminary results and on improvements made over previous studies, we foresee advances and applications in the current state of the art of this family of algorithms and their applications to centrality measurement.

scholarly journals Planar Prior Assisted PatchMatch Multi-View Stereo

2020 ◽  
Vol 34 (07) ◽  
pp. 12516-12523
Author(s):  
Qingshan Xu ◽  
Wenbing Tao
Keyword(s):  
Graphical Model ◽  
State Of The Art ◽  
Depth Estimation ◽  
3D Models ◽  
The Other ◽  
Depth Information ◽  
Probabilistic Graphical Model ◽  
Challenging Problem ◽  
Matching Cost ◽  
Planar Regions

The completeness of 3D models is still a challenging problem in multi-view stereo (MVS) due to the unreliable photometric consistency in low-textured areas. Since low-textured areas usually exhibit strong planarity, planar models are advantageous to the depth estimation of low-textured areas. On the other hand, PatchMatch multi-view stereo is very efficient for its sampling and propagation scheme. By taking advantage of planar models and PatchMatch multi-view stereo, we propose a planar prior assisted PatchMatch multi-view stereo framework in this paper. In detail, we utilize a probabilistic graphical model to embed planar models into PatchMatch multi-view stereo and contribute a novel multi-view aggregated matching cost. This novel cost takes both photometric consistency and planar compatibility into consideration, making it suited for the depth estimation of both non-planar and planar regions. Experimental results demonstrate that our method can efficiently recover the depth information of extremely low-textured areas, thus obtaining high complete 3D models and achieving state-of-the-art performance.

Current State of the Art: Problem-Driven Multi-Functional Bio-Inspired Designs

2019 ◽  
Author(s):  
Devesh Bhasin ◽  
Daniel A. McAdams
Keyword(s):  
Engineering Design ◽  
State Of The Art ◽  
The Other ◽  
Current State ◽  
Other Hand ◽  
Design Generation ◽  
Biomimetic Approach ◽  
Functional Solution

Abstract The development of multi-functional designs is one of the prime reasons to adopt bio-inspired design in engineering design. However, the development of multi-functional bio-inspired designs is mostly solution-driven, in the sense that an available multi-functional solution drives the search for a problem that can be solved by implementing the available solution. The solution-driven nature of the approach restricts the engineering designers to the use of the function combinations found in nature. On the other hand, a problem-driven approach to multi-functional designs allows the designers to form some combination of functions best suited for the problem at hand. However, few works exist in the literature that focus on the development of multi-functional bio-inspired solutions from a problem-driven perspective. In this work, we analyze the existing works that aid the designers in combining multiple biological strategies to develop multi-functional bio-inspired designs. The analysis is carried out by comparing and contrasting the existing frameworks that support multi-functional bio-inspired design generation. The criteria of comparison are derived from the steps involved in the unified problem-driven biomimetic approach. In addition, we qualitatively compare the multi-functional bio-inspired designs developed using existing frameworks to the multi-functional designs existing in biology. Our aim is to explore the capabilities and limitations of current methods to support the generation multi-functional bio-inspired designs.

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