A FAST STRAIGHT-SKELETON ALGORITHM BASED ON GENERALIZED MOTORCYCLE GRAPHS

2012 ◽  
Vol 22 (05) ◽  
pp. 471-498 ◽  
Author(s):  
STEFAN HUBER ◽  
MARTIN HELD
Keyword(s):  
Time Complexity ◽  
Desktop Computer ◽  
Text Memory ◽  
Straight Line ◽  
Memory Footprint ◽  
Industrial Strength ◽  
Graphics Rendering ◽  
Point Arithmetic ◽  
Theoretical Foundations

This paper deals with the fast computation of straight skeletons of planar straight-line graphs (PSLGs) at an industrial-strength level. We discuss both the theoretical foundations of our algorithm and the engineering aspects of our implementation Bone. Our investigation starts with an analysis of the triangulation-based algorithm by Aichholzer and Aurenhammer and we prove the existence of flip-event-free Steiner triangulations. This result motivates a careful generalization of motorcycle graphs such that their intimate geometric connection to straight skeletons is maintained. Based on the generalized motorcycle graph, we devise a non-procedural characterization of straight skeletons of PSLGs and we discuss how to obtain a discretized version of a straight skeleton by means of graphics rendering. Most importantly, this generalization allows us to present a fast and easy-to-implement straight-skeleton algorithm. We implemented our algorithm in C++ based on floating-point arithmetic. Extensive benchmarks with our code Bone demonstrate an [Formula: see text] time complexity and [Formula: see text] memory footprint on 22 300 datasets of diverse characteristics. This is a linear factor better than the implementation provided by CGAL 4.0, which shows an [Formula: see text] time complexity and an [Formula: see text] memory footprint; the CGAL code has been the only fully-functional straight-skeleton code so far. In particular, on datasets with ten thousand vertices, Bone requires about 0.2–0.6 seconds instead of 4–7 minutes consumed by the CGAL code, and Bone uses only 20 MB heap memory instead of several gigabytes. We conclude our paper with a discussion of the engineering aspects and principles that make Bone reliable enough to compute the straight skeleton of datasets comprising a few million vertices on a desktop computer.

scholarly journals A New Method for the Extraction of Diode Parameters Using a Single Exponential Model

2000 ◽  
Vol 22 (3) ◽  
pp. 157-163 ◽  
Author(s):  
S. Dib ◽  
M. De La Bardonnie ◽  
A. Khoury ◽  
F. Pelanchon ◽  
P. Mialhe
Keyword(s):  
Least Squares Method ◽  
Exponential Model ◽  
New Method ◽  
Ordinate Axis ◽  
Straight Line ◽  
Current Voltage ◽  
Method Approach ◽  
Single Exponential

A new method for extracting junction parameters of the single diode model is presented. A least squares method approach considers the deviation ∆V=f(I) between the experimental current-voltage (I-V) characteristic and a theoretical arbitrary characteristic. A specific case- the ∆V graph reducing to a straight line–is identified and the knowledge of the slope and of the intercept with the ordinate axis leads to the determination of the junction parameters. The method is applied to the characterization of the emitter-base junction of transistors and the results are discussed.

CHARACTERIZATION OF THE FUNCTIONAL ADHESION PROPERTY OF THE MONOCYTE FIBRINOGEN RECEPTOR WITH A MONOCLONAL ANTIBODY (Mab) DIRECTED TO THE ACTIVATED STATE OF THE PLATELET GLYCOPROTEIN (GP) IIb/IIIa

1987 ◽  
Author(s):  
Dario C Altieri ◽  
Rossella Bader ◽  
Pier M Mannucci
Keyword(s):  
Surface Antigen ◽  
Platelet Glycoprotein ◽  
Blood Monocytes ◽  
Adhesion Properties ◽  
Fibrinogen Receptor ◽  
Plot Analysis ◽  
Straight Line ◽  
Platelet Receptor ◽  
Activated State

We recently showed that human blood monocytes bind fibrinogen through a genuine surface antigen only in part similar to the platelet GP Ilb/IIIa. Moreover, some anti-GP IIb/IIIa Mabs cross-react with monocytes. In this study we used the 7E3 Mab which preferentially binds to the activated conformation of the platelet GP IIb/IIIa to characterize the dynamic mechanism of "exposure" of the monocyte fibrinogen receptor. 7E3 Mab (25 μg/ml) completely suppressed the binding of i25I-fibrinogen to ADP (10μM)-stimulated monocytes. However, differently from the platelet GP IIb/IIIa, 125I-7E3 binding to unstimulated monocytes was a non-specific and non-saturable reaction. In contrast, after stimulation with ADP (10 μM), suspensions of human monocytes bound 125I-7E3 with saturation of 25-30 μg/ml of added Mab. Scatchard plot analysis was a single-affinity straight line revealing 97,400 binding sites/monocyte with a dissociation constant of 5.2×10−8 M. The monocyte surface antigen uniquely expressed after ADP-activation recognized by 7E3 was visualized by immunoprecipitation studies. Surface iodinated platelet lysate subjected to immunoprecipitation with 7E3 revealed a single band with molecular weight (Mr) of 116,000 corresponding to the platelet GP IIb/IIIa. In contrast, monocytes showed a dimeric surface antigen precipitated by 7E3 in two subunits with Mr=l55,000 and 95,000 respectively. These data indicate that the adhesion properties of the monocyte fibrinogen receptor defined by an anti-platelet GP IIb/IIIa cross-reacting Mab are structurally and functionally distinct from those of the platelet receptor.

scholarly journals On a Class of Polar Log-Aesthetic Curves

2021 ◽  
Author(s):  
Victor Parque
Keyword(s):  
Industrial Design ◽  
Polar Coordinate System ◽  
Navigation Systems ◽  
Straight Line ◽  
Manufactured Products ◽  
Bird Eggs ◽  
Polar Coordinate ◽  
Specific Curvature

Abstract Curves are essential concepts that enable compounded aesthetic curves, e.g., to assemble complex silhouettes, match a specific curvature profile in industrial design, and construct smooth, comfortable, and safe trajectories in vehicle-robot navigation systems. New mechanisms able to encode, generate, evaluate, and deform aesthetic curves are expected to improve the throughput and the quality of industrial design. In recent years, the study of (log) aesthetic curves have attracted the community’s attention due to its ubiquity in natural phenomena such as bird eggs, butterfly wings, falcon flights, and manufactured products such as Japanese swords and automobiles. A (log) aesthetic curve renders a logarithmic curvature graph approximated by a straight line, and polar aesthetic curves enable to mode user-defined dynamics of the polar tangential angle in the polar coordinate system. As such, the curvature profile often becomes a by-product of the tangential angle. In this paper, we extend the concept of polar aesthetic curves and establish the analytical formulations to construct aesthetic curves with user-defined criteria. In particular, we propose the closed-form analytic characterizations of polar log-aesthetic curves meeting user-defined criteria of curvature profiles and dynamics of polar tangential angles. We present numerical examples portraying the feasibility of rendering the logarithmic curvature graphs represented by a straight line. Our approach enables the seamless characterization of aesthetic curves in the polar co-ordinate system, which can model aesthetic shapes with desirable aesthetic curvature profiles.

scholarly journals The Performance on Slope Number of Hypercube, Normal Representation of Butterfly and Benes Networks

2019 ◽  
Vol 9 (1) ◽  
pp. 2349-2352
Keyword(s):  
Quality Measures ◽  
Parallel Architectures ◽  
Line Segments ◽  
Normal Representation ◽  
Straight Line ◽  
Benes Networks

Many quality measures have been defined for graph drawings. In order to optimize these measures, slope number is considered to minimize the distinct edge slopes. The edges of the graphs are designed here as straight line segments. A number of distinct slopes required to draw the graph is called slope number. In this paper the slopenumber is discussed for known parallel architectures like hypercube, butterfly and benes networks. In addition to that the characterization of these networks is investigated and the results are observed for the defined problem.

scholarly journals Verification of connectivity of electrical connections in topology of radio electronic equipment products

2019 ◽  
pp. 21-25
Author(s):  
G. N. Brusnikin
Keyword(s):  
Time Complexity ◽  
Undirected Graph ◽  
Electronic Equipment ◽  
Large Dimension ◽  
Complexity Of Algorithms ◽  
Colored Graphs ◽  
Straight Line ◽  
Effective Use ◽  
Electrical Connections

The solution of the problem of verifying the connectivity of electrical connections in the VLSI topology is considered. Effective use of computing resources is based on the use of quasi‑linear computational (temporal and capacitive) complexity of algorithms: sweeping the plane of a straight line for constructing a graph of electrical connections; allocation of subsets of connected vertices in the components of the connection of an undirected graph of large dimension for the determination of electrically connected contacts; establish isomorphism of component‑full colored graphs for comparing the restored list with the original list of electrical connections The proposed solution has a time complexity O(N + N log2 N ) and the capacitive complexity O(s + N ), where N is the number of elements in the topology and s is the number of contacts in the source circuit.

scholarly journals Predation and oviposition potential of Brazilian populations of the predatory mite Amblyseius tamatavensis (Acari: Phytoseiidae) on eggs of Bemisia tabaci (Insecta: Hemiptera)

Acarologia ◽  
2019 ◽  
Vol 59 (1) ◽  
pp. 120-128
Author(s):  
Marcela Massaro ◽  
Gilberto J. de Moraes
Keyword(s):  
Bemisia Tabaci ◽  
Morphological Characterization ◽  
Straight Line ◽  
Straight Line Distance ◽  
Vector Insect ◽  
Mixed Origin ◽  
Biotype B ◽  
Two Populations ◽  
Biological Differences

Amblyseius tamatavensis has been reported from over 20 countries around the world, and is also widely distributed in Brazil. It has been reported as potentially useful for the control of Bemisia tabaci, a pest/vector insect of great economic importance worldwide. Some studies have reported some biological differences among phytoseiid populations. The objective of this work was to compare 14 populations of different regions of Brazil (from the states of Alagoas, Goiás, Minas Gerais and São Paulo; straight line distance between northern and southern extremes of 2,560 km) in relation to the predation and oviposition potential when fed with eggs of B. tabaci biotype B. The morphological characterization of these mites showed that the population from Olhos d'Agua das Flores (Alagoas state) and a population from mixed origin maintained in the laboratory for about 5 years were constituted by mites with larger dorsal and ventrianal shield dimensions and presented the highest rates of daily predation (respectively 7.9 and 7.0 eggs/ female) and oviposition (1.2 and 1.1 eggs/ female). A positive and significant relationship was observed between mean population predation and oviposition rates. The results suggest that subsequent efforts should focus on exploring the variability of mites of these two populations in relation to predation and oviposition potential, in order to select a new, more promising population to control B . tabaci biotype B.

scholarly journals COMPARISON OF CHARACTERIZATION OF FIGHTING ROOSTER (Gallus gallus) SEMEN EJACULATES RECOVERED BY ELECTROEJACULATION AND DORSAL MASSAGE TECHNIQUES

SPERMOVA ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 32-38
Author(s):  
Andres Moscoso Piedra ◽  
◽  
Marco Muñoz ◽  
Daniel Argudo Garzon ◽  
Jorge Samaniego ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Gallus Gallus ◽  
Quality Parameters ◽  
Sperm Viability ◽  
Lower Response ◽  
Semen Collection ◽  
Straight Line ◽  
A Priority

Implementing alternatives methods to dorsal massage (e.g., electroejaculation) for recovering semen from fighting rooster, known to be very stressful due to its aggressiveness, has become a priority for breeders of this cock breed in Ecuador. Therefore, the objective of the present study was to evaluate two semen collection techniques in fighting roosters, one by electroejaculation (EE) and another by dorsal massage (DM) on seminal quality parameters. For this purpose, thirty attempts of semen recovery from six adult Spanish fighting roosters were carried out using DM (n = 12) and EE (n = 18). Electroejaculation was performed previous sedation, applying five stimulation cycles (of 2 s) generated from a handmade electroejaculation probe (9 to 12 V). The results showed that the EE produced lower response (P < 0.01) to semen ejaculation than the DM (44.4 % vs. 100.0 %, respectively). However, semen samples obtained by EE had better (P < 0.05) spermatic kinetic with greater values of straight-line velocity (VSL, µm/s), average path velocity (VAP, µm/s), and beat-cross frequency (BCF, Hz) as well as higher percentages (P < 0.01) of wobble and linearity compared to DM, irrespective of sperm viability. In addition, the number of urates present in the ejaculates obtained by EE was lower (P < 0.05) than those obtained by DM. In conclusion, electrical stimulation with prior sedation produced a low semen ejaculation response in fighting cocks. However, EE yielded semen ejaculates with better spermatic kinetic compared with the conventional dorsal massage technique.

Variance weighting functions in radioimmunoassay calibration

1986 ◽  
Vol 251 (3) ◽  
pp. E357-E361 ◽  
Author(s):  
T. W. Gettys ◽  
P. M. Burrows ◽  
D. M. Henricks
Keyword(s):  
Counting Rate ◽  
Weighting Function ◽  
Weighted Least Squares ◽  
Weighting Functions ◽  
Software Packages ◽  
Precise Estimation ◽  
Straight Line ◽  
Mean And Variance ◽  
The Relationship

Software packages for radioimmunoassay calibration assume that expected counting rate is a function of ligand dose. Previous studies have indicated that variances of counting rate are also related to dose, but the structure of individual assays does not permit precise estimation of counting rate variances at individual doses. The method described here uses results from an accumulation of assays to characterize the relationship between mean and variance of counting rate, thus providing a variance weighting function for the calibration. Analysis of 140 cortisol assays, all with two replicates of each of 50 sources (9 standard doses, 3 quality control preps, and 38 unknowns), led to an asymmetric rising ogive relating variances to means of counting rates. A rectangular hyperbola provided an adequate characterization of this relationship in an accumulation of 21 testosterone assays. Relationships between mean and variance of counting rate in 19 growth hormone assays and 7 triiodothyronine assays were characterized by a straight line and a rising exponential curve, respectively. Calibration curves, such as the commonly adopted logistic ogive in relation to log dose, are fitted by weighted least squares to observed counts directly using empirical weights proportional to the reciprocal of estimated counting variance. The advantage of this method is that all observations contribute to the calibration in accordance with their merit.

SHORTEST DESCENDING PATHS: TOWARDS AN EXACT ALGORITHM

2011 ◽  
Vol 21 (04) ◽  
pp. 431-466 ◽  
Author(s):  
MUSTAQ AHMED ◽  
ANNA LUBIW
Keyword(s):  
Approximation Algorithms ◽  
Polynomial Time ◽  
Shortest Path ◽  
Exact Algorithm ◽  
Full Characterization ◽  
Polynomial Time Algorithms ◽  
Straight Line ◽  
Bend Angles ◽  
Special Classes

A path from s to t on a polyhedral terrain is descending if the height of a point p never increases while we move p along the path from s to t. Although a shortest path on a terrain unfolds to a straight line, a shortest descending path (SDP) does not. We give a full characterization of the bend angles of an SDP, showing that they follow a generalized form of Snell's law of refraction of light. The complexity of finding SDPs is open—only approximation algorithms are known. We reduce the SDP problem to the problem of finding an SDP through a given sequence of faces. We give polynomial time algorithms for SDPs on two special classes of terrains, but argue that the general case will be difficult.

Sign in / Sign up

Export Citation Format

Share Document