Uniqueness and minimality of large face-width embeddings of graphs

COMBINATORICA ◽  
1995 ◽  
Vol 15 (4) ◽  
pp. 541-556 ◽  
Author(s):  
Bojan Mohar
Keyword(s):  
Face Width ◽  
Large Face

scholarly journals Asymptotic properties of rooted 3-connected maps on surfaces

1996 ◽  
Vol 60 (1) ◽  
pp. 31-41 ◽  
Author(s):  
Edward A. Bender ◽  
Zhicheng Gao ◽  
L. Bruce Richmond ◽  
Nicholas C. Wormald
Keyword(s):  
Asymptotic Properties ◽  
Face Width ◽  
Almost All ◽  
Large Face

AbstractIn this paper we obtain asymptotics for the number of rooted 3-connected maps on an arbitrary surface and use them to prove that almost all rooted 3-connected maps on any fixed surface have large edge-width and large face-width. It then follows from the result of Roberston and Vitray [10] that almost all rooted 3-connected maps on any fixed surface are minimum genus embeddings and their underlying graphs are uniquely embeddable on the surface.

scholarly journals The Crossing Number of a Projective Graph is Quadratic in the Face–Width

10.37236/770 ◽  
2008 ◽  
Vol 15 (1) ◽  
Author(s):  
I. Gitler ◽  
P. Hliněný ◽  
J. Leaños ◽  
G. Salazar
Keyword(s):  
Approximation Algorithm ◽  
Projective Plane ◽  
Crossing Number ◽  
Orientable Surface ◽  
Constant Factor ◽  
Bounded Degree ◽  
Face Width ◽  
Projective Graph ◽  
The Face ◽  
Large Face

We show that for each integer $g\geq0$ there is a constant $c_g > 0$ such that every graph that embeds in the projective plane with sufficiently large face–width $r$ has crossing number at least $c_g r^2$ in the orientable surface $\Sigma_g$ of genus $g$. As a corollary, we give a polynomial time constant factor approximation algorithm for the crossing number of projective graphs with bounded degree.

scholarly journals Asymptotic Enumeration of Labelled Graphs by Genus

10.37236/500 ◽  
2011 ◽  
Vol 18 (1) ◽  
Author(s):  
Edward A. Bender ◽  
Zhicheng Gao
Keyword(s):  
Orientable Surface ◽  
Asymptotic Formulas ◽  
Asymptotic Enumeration ◽  
Connected Graphs ◽  
Face Width ◽  
Surface Maps ◽  
Connected Surface ◽  
Labelled Graphs ◽  
Large Face

We obtain asymptotic formulas for the number of rooted 2-connected and 3-connected surface maps on an orientable surface of genus $g$ with respect to vertices and edges simultaneously. We also derive the bivariate version of the large face-width result for random 3-connected maps. These results are then used to derive asymptotic formulas for the number of labelled $k$-connected graphs of orientable genus $g$ for $k\le3$.

Effects of misalignment on load distribution in large face-width helical gears

2003 ◽  
Vol 217 (2) ◽  
pp. 93-98 ◽  
Author(s):  
J Haigh ◽  
J N Fawcett
Keyword(s):  
Load Distribution ◽  
Experimental Results ◽  
Helical Gears ◽  
Face Width ◽  
Stress Levels ◽  
The Uk ◽  
The University ◽  
Large Face

Experimental results, obtained from the UK 8 MW facility for gear research at the University of Newcastle, are presented, which show how the load distribution across a large face-width gear varies with misalignment. Tests were carried out over a range of torque conditions using pinion flanks which were crowned or which had lead modification. The crowned flanks were shown to be more tolerant of misalignment but, at low misalignments, gave slightly higher stress levels than those with lead modification.

Improving the Characteristics of Gear Pumps: Part A — Discharge

2003 ◽  
Author(s):  
Ahmed M. M. El-Bahloul ◽  
Yasser Z. R. Ali
Keyword(s):  
Correction Factor ◽  
Helix Angle ◽  
Tooth Profile ◽  
Radius Of Curvature ◽  
Circular Arc ◽  
Pressure Angle ◽  
Face Width ◽  
Angle Change ◽  
Number Of Teeth ◽  
Gear Pumps

The main objective of this paper is to study the effect of gear geometry on the discharge of gear pumps. We have used gears of circular-arc tooth profile as gear pumps and have compared between these types of gearing and spur, helical gear pumps according to discharge. The chosen module change from 2 to 16 mm, number of teeth change from 8 to 20 teeth, pressure angle change from 10 to 30 deg, face width change from 20 to 120 mm, correction factor change from −1 to 1, helix angle change from 5 to 30 deg, and radii of curvature equal 1.4, 1.5, 2, 2.5, 2.75, and 3m are considered. The authors deduced that the tooth rack profile with radius of curvature equal 2.5, 2.75, 3m for all addendum circular arc tooth and convex-concave tooth profile, and derived equations representing the tooth profile, and calculated the points of intersections between curves of tooth profile. We drive the formulas for the volume of oil between adjacent teeth. Computer program has been prepared to calculate the discharge from the derived formulae with all variables for different types of gear pumps. Curves showing the change of discharge with module, number of teeth, pressure angle, face width, correction factor, helix angle, and radius of curvature are presented. The results show that: 1) The discharge increases with increasing module, number of teeth, positive correction factor, face width and radius of curvature of the tooth. 2) The discharge increases with increasing pressure angle to a certain value and then decreases with increasing pressure angle. 3) The discharge decreases with increasing helix angle. 4) The convex-concave circular-arc gears gives discharge higher than that of alla ddendum circular arc, spur, and helical gear pumps respectively. 5) A curve fitting of the results are done and the following formulae derived for the discharge of involute and circular arc gear pumps respectively: Q=A1bm2z0.895e0.065xe0.0033αe−0.0079βQ=A2bm2z0.91ρ10.669e−0.0047β

The effect of space allowance and milk yield level on the performance and behaviour of dairy cattle housed in straw yards

1998 ◽  
Vol 1998 ◽  
pp. 108-108
Author(s):  
J. A. Fregonesi ◽  
J.D. Leaver
Keyword(s):  
Dairy Cattle ◽  
Milk Yield ◽  
Stocking Density ◽  
Important Variable ◽  
Early Lactation ◽  
Ways Of Coping ◽  
Yield Level ◽  
Face Width ◽  
Holstein Friesian ◽  
Friesian Cows

Space allowance could be an important variable affecting production, health, reproductive performance and behaviour of dairy cattle. Also, high and low yielding cows may have different ways of coping with insufficient space allowance. The aim of this experiment was to study the influence of space allowance and milk yield level on the performance and behaviour of strawyard housed dairy cows.The experiment was carried out using 24 Holstein Friesian cows with two groups in early lactation of high (over 30 kg/day milk yield) and two groups in late lactation of low yield (under 25 kg/day milk yield). The groups were allocated to strawyard systems with low stocking density (bed area/cow = 9 m2; pen area/cow = 13.5 m2; feed face width/cow = 1.5 m) or high stocking density (bed area/cow = 4.5 m2; pen area/cow = 6.75 m2; feed face width/cow = 0.75m) conforming to a changeover design with two periods, each of four weeks. The cows were fed a total mixed ration ad libitum and 2kg/cow/day of concentrate in the milking parlour. All animals were milked twice daily.

Teaching Large Sections of a Business Communication Course

2017 ◽  
Vol 80 (1) ◽  
pp. 114-129
Author(s):  
Carol Wright
Keyword(s):  
Student Learning ◽  
Business Communication ◽  
Pedagogical Strategies ◽  
Communication Course ◽  
Face To Face ◽  
Large Sections ◽  
Large Face

The purpose of this research is to examine specific examples of how business communication courses are delivered in large, face-to-face university classes to discover implications of these large courses. This case study reviewed four classes from two different midsized universities whose classes range from 48 to 300 students. Findings suggest that, when faced with the possibility of teaching more students, it is important to understand that pedagogical strategies may need to be adjusted to maintain student learning. These strategies include modifying the course to the lecture/lab structure, limiting the amount of writing, or allowing the instructor to teach fewer courses.

scholarly journals Correlation of morphological parameters of donkey from Austria

2021 ◽  
Vol 53 (2) ◽  
Author(s):  
Darko Drobnjak ◽  
Radka Vlaeva ◽  
Goran Stanišić ◽  
Radomir Mandić ◽  
Natalija Grittner ◽  
...  
Keyword(s):  
Body Length ◽  
Pearson Correlation ◽  
Good Reason ◽  
Statistical Correlation ◽  
Head Length ◽  
Chest Circumference ◽  
Average Height ◽  
Face Width ◽  
Equus Asinus ◽  
Almost All

The donkey, as a work animal, is gradually losing its value. Agriculture industrialization, mechanization of many processes on mountain and valley farms have lead to a reduction of donkey livestock. This reduction gives cause for concern, and is good reason to study all aspects of these domestic animals in order to revive its role, to restart livestock growth in its familiar habitats, and to introduce it into new environments. This study focuses on these aspects. The domestic donkey (Equus asinus) originated from Africa, and there are two kinds of African donkeys: Nubian and Somali. Their enormous, almost mystical, endurance is well known. There is no place in the world where a donkey is not able to perform the most difficult work, above all in transporting goods. A donkey has an amazing capability of stable movement through the most difficult places. For study sample consisted of 44 donkeys (28 males and 16 females) from Austria. The following morphometric parameters were analysed: height at the withers, height at the back, height of the croup, body length, chest depth, chest width, chest circumference anterior, chest circumference posterior, shin circumference, head length, skull length, face length, skull width, face width, length of ears. Measurements were performed using a ruler, tape measure and vernier callipers. The average height at the withers of males was 116.40 cm, ranging from 99.60 to 140.60 cm, while for females, the average was 102.38 cm, ranging from 90.50 to 125.70 cm. Body length of males was on average 121.85 cm with a standard deviation of 11.79, while the mean body length for females is 115.80 cm, with a range of 101.00 to 131.00 cm. Male head length ranged from 48.00 to 71.00 cm, with an average of 55.60 cm, while in females, head length was on average 50.06 cm, ranging from 43.00 to 56.00 cm. Using the Pearson correlation, a very significant or significant positive statistical correlation was observed between almost all parameters of males, while for females, Pearson correlation values had slightly different values than for males. There was no statistically significant correlation between chest width and anterior chest circumference with nearly any other parameters. For females, a negative correlation between the skull width and all other parameters was also observed.

scholarly journals Face morphology of brazilian and peruvian populations: analysis of proportion and linear measurement indexes

2017 ◽  
Vol 20 (3) ◽  
Author(s):  
Elaine Cristina Sousa Dos Santos ◽  
Diego Jesus Bradariz Pimentel ◽  
Laís Lopes Machado De Matos ◽  
Laís Valencise Magri ◽  
Ana Maria Bettoni Rodrigues Da Silva ◽  
...  
Keyword(s):  
Latin American ◽  
Linear Measurement ◽  
Linear Measurements ◽  
3D Images ◽  
Brazilian Sample ◽  
Face Width ◽  
The Face ◽  
Mouth Width ◽  
3D Stereophotogrammetry ◽  
Face Morphology

<p><strong>Objective: </strong>To compare the proportion and linear measurement indexes between Brazilian and Peruvian population through 3D stereophotogrammetry and to stablish the face profile of these two Latin American populations. <strong>Material and Methods: </strong>40 volunteers (Brazilian n=21– 10 males and 11 females; Peruvian n=19 – 8 males and 11 females) aged between 18 and 40 years (mean of 28.7±9.1) had landmarks marked on the face. Then, 3D images were obtained (VECTRA M3) and the indexes of proportion and linear measurement (face, nose, and lips) were calculated. The data were statistically analyzed by One-Way ANOVA (p&lt;0.05). <strong>Results: </strong>The proportion indexes did not reveal marked differences either between the studied populations or genders (p&gt;0.05). The following linear measurements showed intergroup statistically significant differences: face width and height, nose width and height, upper facial height, mouth width, protrusion of the nose tip (p&lt;0.05). The Brazilian females showed the smallest significant differences. <strong>Conclusions: </strong>Despite the different ethnic compositions, the Brazilian and Peruvian populations did not differ regarding the proportions of the face, nose, and lips. The differences observed in Brazilian females may be related to gender and/or to the Caucasian heritage of the Brazilian sample.</p><p><strong>Keywords</strong></p><p>Photogrammetry; Face; Tridimensional Image.<strong></strong></p>

Sign in / Sign up

Export Citation Format

Share Document