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Author Gielis, J. openurl 
  Title Er bestaan geen absurde, irrationele, onregelmatige of onderling niet-onmeetbare meetkundige getallen Type A2 Journal article
  Year 2021 Publication (down) Wiskunde en onderwijs Abbreviated Journal  
  Volume 47 Issue 188 Pages 23-33  
  Keywords A2 Journal article; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2032-0485 ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ admin @ c:irua:183083 Serial 7934  
Permanent link to this record
 

 
Author Shi, P.; Liu, M.; Ratkowsky, D.A.; Gielis, J.; Su, J.; Yu, X.; Wang, P.; Zhang, L.; Lin, Z.; Schrader, J. pdf  url
doi  openurl
  Title Leaf area-length allometry and its implications in leaf shape evolution Type A1 Journal article
  Year 2019 Publication (down) Trees: structure and function Abbreviated Journal  
  Volume 33 Issue 4 Pages 1073-1085  
  Keywords A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract According to Thompson’s principle of similarity, the area of an object should be proportional to its length squared. However, leaf area–length data of some plants have been demonstrated not to follow the principle of similarity. We explore the reasons why the leaf area–length allometry deviates from the principle of similarity and examine whether there is a general model describing the relationship among leaf area, width and length. We sampled more than 11,800 leaves from six classes of woody and herbaceous plants and tested the leaf area–length allometry. We compared six mathematical models based on root-mean-square error as the measure of goodness-of-fit. The best supported model described a proportional relationship between leaf area and the product of leaf width and length (i.e., the Montgomery model). We found that the extent to which the leaf area–length allometry deviates from the principle of similarity depends upon the extent of variation of the ratio of leaf width to length. Estimates of the parameter of the Montgomery model ranged between 1/2, which corresponds to a triangular leaf with leaf length as its height and leaf width as its base, and π/4, which corresponds to an elliptical leaf with leaf length as its major axis and leaf width as its minor axis, for the six classes of plants. The narrow range in practice of the Montgomery parameter implies an evolutionary stability for the leaf area of large-leaved plants despite the fact that leaf shapes of these plants are rather different.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000475992600010 Publication Date 2019-04-04  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0931-1890; 1432-2285 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:159970 Serial 8170  
Permanent link to this record
 

 
Author Lian, M.; Shi, P.; Zhang, L.; Yao, W.; Gielis, J.; Niklas, K.J. pdf  url
doi  openurl
  Title A generalized performance equation and its application in measuring the Gini index of leaf size inequality Type A1 Journal article
  Year 2023 Publication (down) Trees: structure and function Abbreviated Journal  
  Volume 37 Issue Pages 1555-1565  
  Keywords A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract The goal of this study is to provide a rigorous tool to quantify the inequality of the leaf size distribution of an individual plant, thereby serving as a reference trait for quantifying plant adaptations to local environmental conditions. The tool to be presented and tested employs three components: (1) a performance equation (PE), which can produce flexible asymmetrical and symmetrical bell-shaped curves, (2) the Lorenz curve (i.e., the cumulative proportion of leaf size vs. the cumulative proportion of number of leaves), which is the basis for calculating, and (3) the Gini index, which measures the inequality of leaf size distribution. We sampled 12 individual plants of a dwarf bamboo and measured the area and dry mass of each leaf of each plant. We then developed a generalized performance equation (GPE) of which the PE is a special case and fitted the Lorenz curve to leaf size distribution using the GPE and PE. The GPE performed better than the PE in fitting the Lorenz curve. We compared the Gini index of leaf area distribution with that of leaf dry mass distribution and found that there was a significant difference between the two indices that might emerge from the scaling relationship between leaf dry mass and area. Nevertheless, there was a strong correlation between the two Gini indices (r2 = 0.9846). This study provides a promising tool based on the GPE for quantifying the inequality of leaf size distributions across individual plants and can be used to quantify plant adaptations to local environmental conditions.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001069570200001 Publication Date 2023-08-26  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0931-1890; 1432-2285 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.3 Times cited Open Access Not_Open_Access: Available from 26.02.2024  
  Notes Approved Most recent IF: 2.3; 2023 IF: 1.842  
  Call Number UA @ admin @ c:irua:199562 Serial 8874  
Permanent link to this record
 

 
Author Gielis, J.; Verhulst, R.; Caratelli, D.; Ricci, P.E.; Tavkhelidze, I. url  openurl
  Title On means, polynomials and special functions Type A1 Journal article
  Year 2014 Publication (down) The teaching of mathematics Abbreviated Journal  
  Volume 17 Issue 1 Pages 1-20  
  Keywords A1 Journal article; Educational sciences; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1451-4966; 2406-1077 ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:128660 Serial 8327  
Permanent link to this record
 

 
Author Shi, P.; Ratkowsky, D.A.; Gielis, J. url  doi
openurl 
  Title The generalized Gielis geometric equation and its application Type A1 Journal article
  Year 2020 Publication (down) Symmetry-Basel Abbreviated Journal Symmetry-Basel  
  Volume 12 Issue 4 Pages 645-10  
  Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract Many natural shapes exhibit surprising symmetry and can be described by the Gielis equation, which has several classical geometric equations (for example, the circle, ellipse and superellipse) as special cases. However, the original Gielis equation cannot reflect some diverse shapes due to limitations of its power-law hypothesis. In the present study, we propose a generalized version by introducing a link function. Thus, the original Gielis equation can be deemed to be a special case of the generalized Gielis equation (GGE) with a power-law link function. The link function can be based on the morphological features of different objects so that the GGE is more flexible in fitting the data of the shape than its original version. The GGE is shown to be valid in depicting the shapes of some starfish and plant leaves.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000540222200156 Publication Date 2020-04-21  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2073-8994 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.7 Times cited 4 Open Access  
  Notes ; This research was funded by the Jiangsu Government Scholarship for Overseas Studies (grant number: JS-2018-038). ; Approved Most recent IF: 2.7; 2020 IF: 1.457  
  Call Number UA @ admin @ c:irua:168141 Serial 6526  
Permanent link to this record
 

 
Author Huang, W.; Li, Y.; Niklas, K.J.; Gielis, J.; Ding, Y.; Cao, L.; Shi, P. url  doi
openurl 
  Title A superellipse with deformation and its application in describing the cross-sectional shapes of a square bamboo Type A1 Journal article
  Year 2020 Publication (down) Symmetry-Basel Abbreviated Journal Symmetry-Basel  
  Volume 12 Issue 12 Pages 2073  
  Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract Many cross-sectional shapes of plants have been found to approximate a superellipse rather than an ellipse. Square bamboos, belonging to the genus Chimonobambusa (Poaceae), are a group of plants with round-edged square-like culm cross sections. The initial application of superellipses to model these culm cross sections has focused on Chimonobambusa quadrangularis (Franceschi) Makino. However, there is a need for large scale empirical data to confirm this hypothesis. In this study, approximately 750 cross sections from 30 culms of C. utilis were scanned to obtain cross-sectional boundary coordinates. A superellipse exhibits a centrosymmetry, but in nature the cross sections of culms usually deviate from a standard circle, ellipse, or superellipse because of the influences of the environment and terrain, resulting in different bending and torsion forces during growth. Thus, more natural cross-sectional shapes appear to have the form of a deformed superellipse. The superellipse equation with a deformation parameter (SEDP) was used to fit boundary data. We find that the cross-sectional shapes (including outer and inner rings) of C. utilis can be well described by SEDP. The adjusted root-mean-square error of SEDP is smaller than that of the superellipse equation without a deformation parameter. A major finding is that the cross-sectional shapes can be divided into two types of superellipse curves: hyperellipses and hypoellipses, even for cross sections from the same culm. There are two proportional relationships between ring area and the product of ring length and width for both the outer and inner rings. The proportionality coefficients are significantly different, as a consequence of the two different superellipse types (i.e., hyperellipses and hypoellipses). The difference in the proportionality coefficients between hyperellipses and hypoellipses for outer rings is greater than that for inner rings. This work informs our understanding and quantifying of the longitudinal deformation of plant stems for future studies to assess the influences of the environment on stem development. This work is also informative for understanding the deviation of natural shapes from a strict rotational symmetry.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000602546300001 Publication Date 2020-12-15  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2073-8994 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.7 Times cited Open Access  
  Notes Approved Most recent IF: 2.7; 2020 IF: 1.457  
  Call Number UA @ admin @ c:irua:174472 Serial 8622  
Permanent link to this record
 

 
Author Gielis, J. url  doi
openurl 
  Title Fred Van Oystaeyen : Time hybrids: a new generic theory of reality Type Review
  Year 2023 Publication (down) Symmetry, Culture and Science Abbreviated Journal  
  Volume 34 Issue 3 Pages 347-351  
  Keywords Review; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: NA  
  Call Number UA @ admin @ c:irua:199538 Serial 8871  
Permanent link to this record
 

 
Author Chapman, D.; Gielis, J. doi  openurl
  Title Gielis transformations for the audiovisual geometry database Type A1 Journal article
  Year 2021 Publication (down) Symmetry : culture and science Abbreviated Journal  
  Volume 32 Issue 2 Pages 177-180  
  Keywords A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract This publication introduces the audiovisual geometry database with Gielis transformations as initial records for a prototype of the database. A concise overview is given of the rationale behind the database and studying wave phenomena with Gielis transformations. First results on a form of timbral polyphony observed in Gielis curves and future work are briefly discussed.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date 2021-07-02  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0865-4824 ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access Not_Open_Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ admin @ c:irua:180965 Serial 8004  
Permanent link to this record
 

 
Author Gielis, J. pdf  url
doi  openurl
  Title Phi-bonacci in Ancient Greece Type A1 Journal article
  Year 2021 Publication (down) Symmetry : culture and science Abbreviated Journal  
  Volume 32 Issue 1 Pages 25-40  
  Keywords A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract Fibonacci numbers are a very popular subject in mathematics, culture and science. A major open question is why the ancient Greeks overlooked this series, while they were very familiar with the golden mean and division in extreme and mean ratio. Furthermore, they could compute the square root of five to a high degree of precision using Theon 's ladder. This fact is based on tables built with side and diagonal numbers, and it is a simple and incredibly efficient method to compute roots of integers, though it is little known even now among most of the experts. The biologist D 'Arcy Wentworth Thompson showed that the same method could be used to generate the Fibonacci series using a simple shift in the computation of the tables. He argues, quite convincingly, that the ancient Greeks could not have overlooked this. Actually, the same method can be used to generate all possible regular phyllotaxis patterns.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000643822700002 Publication Date 2021-03-30  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0865-4824 ISBN Additional Links UA library record; WoS full record  
  Impact Factor Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: NA  
  Call Number UA @ admin @ c:irua:178322 Serial 8376  
Permanent link to this record
 

 
Author Gielis, J.; Brasili, S. doi  openurl
  Title The apeirogon and dual numbers Type A1 Journal article
  Year 2021 Publication (down) Symmetry : culture and science Abbreviated Journal  
  Volume 32 Issue 2 Pages 157-160  
  Keywords A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract The richness, diversity, connection, depth and pleasure of studying symmetry continue to open doors. Here we report a connection between Coxeter's Apeirogon and the geometry associated with pictorial space, parabolic rotation and dual numbers.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000670122100011 Publication Date 2021-07-02  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0865-4824 ISBN Additional Links UA library record; WoS full record  
  Impact Factor Times cited Open Access Not_Open_Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ admin @ c:irua:179759 Serial 8652  
Permanent link to this record
 

 
Author Gielis, J. url  doi
openurl 
  Title Simon Stevin as a central figure in the development of abstract algebra and generic programming Type A1 Journal article
  Year 2023 Publication (down) Symmetry : culture and science Abbreviated Journal  
  Volume 34 Issue 2 Pages 155-168  
  Keywords A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract Simon Stevin (1548-1620) is mainly known for the decimal system and his Clootkrans proof. His influence is also profound in infinitesimal calculus, mechanics, and even in abstract algebra and today’s conception of polynomials, algorithms, and generic programming. Here we review his influence as assessed in generic programming. According to Dr. Stepanov, one of the most influential researchers in generic programming, Stevin’s work on polynomials can be regarded as the essence of generic programming: an algorithm from one domain can be applied in another similar domain.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001068714100003 Publication Date 2023-07-11  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0865-4824 ISBN Additional Links UA library record; WoS full record  
  Impact Factor Times cited Open Access Not_Open_Access: Available from 08.02.2024  
  Notes Approved Most recent IF: NA  
  Call Number UA @ admin @ c:irua:198000 Serial 8929  
Permanent link to this record
 

 
Author Li, Y.; Quinn, B.K.; Gielis, J.; Li, Y.; Shi, P. url  doi
openurl 
  Title Evidence that supertriangles exist in nature from the vertical projections of Koelreuteria paniculata fruit Type A1 Journal article
  Year 2022 Publication (down) Symmetry Abbreviated Journal Symmetry-Basel  
  Volume 14 Issue 1 Pages 23  
  Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract Many natural radial symmetrical shapes (e.g., sea stars) follow the Gielis equation (GE) or its twin equation (TGE). A supertriangle (three triangles arranged around a central polygon) represents such a shape, but no study has tested whether natural shapes can be represented as/are supertriangles or whether the GE or TGE can describe their shape. We collected 100 pieces of Koelreuteria paniculata fruit, which have a supertriangular shape, extracted the boundary coordinates for their vertical projections, and then fitted them with the GE and TGE. The adjusted root mean square errors (RMSEadj) of the two equations were always less than 0.08, and >70% were less than 0.05. For 57/100 fruit projections, the GE had a lower RMSEadj than the TGE, although overall differences in the goodness of fit were non-significant. However, the TGE produces more symmetrical shapes than the GE as the two parameters controlling the extent of symmetry in it are approximately equal. This work demonstrates that natural supertriangles exist, validates the use of the GE and TGE to model their shapes, and suggests that different complex radially symmetrical shapes can be generated by the same equation, implying that different types of biological symmetry may result from the same biophysical mechanisms.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000746030100001 Publication Date 2021-12-27  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2073-8994 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.7 Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: 2.7  
  Call Number UA @ admin @ c:irua:186453 Serial 7158  
Permanent link to this record
 

 
Author Shi, P.; Wang, L.; Quinn, B.K.K.; Gielis, J. url  doi
openurl 
  Title A new program to estimate the parameters of Preston's equation, a general formula for describing the egg shape of birds Type A1 Journal article
  Year 2023 Publication (down) Symmetry Abbreviated Journal Symmetry-Basel  
  Volume 15 Issue 1 Pages 231-10  
  Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract Preston's equation is a general model describing the egg shape of birds. The parameters of Preston's equation are usually estimated after re-expressing it as the Todd-Smart equation and scaling the egg's actual length to two. This method assumes that the straight line through the two points on an egg's profile separated by the maximum distance (i.e., the longest axis of an egg's profile) is the mid-line. It hypothesizes that the photographed egg's profile is perfectly bilaterally symmetrical, which seldom holds true because of photographic errors and placement errors. The existing parameter estimation method for Preston's equation considers an angle of deviation for the longest axis of an egg's profile from the mid-line, which decreases prediction errors to a certain degree. Nevertheless, this method cannot provide an accurate estimate of the coordinates of the egg's center, and it leads to sub-optimal parameter estimation. Thus, it is better to account for the possible asymmetry between the two sides of an egg's profile along its mid-line when fitting egg-shape data. In this paper, we propose a method based on the optimization algorithm (optimPE) to fit egg-shape data and better estimate the parameters of Preston's equation by automatically searching for the optimal mid-line of an egg's profile and testing its validity using profiles of 59 bird eggs spanning a wide range of existing egg shapes. We further compared this method with the existing one based on multiple linear regression (lmPE). This study demonstrated the ability of the optimPE method to estimate numerical values of the parameters of Preston's equation and provide the theoretical egg length (i.e., the distance between two ends of the mid-line of an egg's profile) and the egg's maximum breadth. This provides a valuable approach for comparing egg shapes among conspecifics or across different species, or even different classes (e.g., birds and reptiles), in future investigations.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000927531000001 Publication Date 2023-01-13  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2073-8994 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 2.7 Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: 2.7; 2023 IF: 1.457  
  Call Number UA @ admin @ c:irua:195347 Serial 7279  
Permanent link to this record
 

 
Author Wang, L.; Ratkowsky, D.A.; Gielis, J.; Ricci, P.E.; Shi, P. url  doi
openurl 
  Title Effects of the numerical values of the parameters in the Gielis equation on its geometries Type A1 Journal article
  Year 2022 Publication (down) Symmetry Abbreviated Journal Symmetry-Basel  
  Volume 14 Issue 12 Pages 2475-12  
  Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract The Lamé curve is an extension of an ellipse, the latter being a special case. Dr. Johan Gielis further extended the Lamé curve in the polar coordinate system by introducing additional parameters (n1, n2, n3; m): rφ=1Acosm4φn2+1Bsinm4φn3−1/n1, which can be applied to model natural geometries. Here, r is the polar radius corresponding to the polar angle φ; A, B, n1, n2 and n3 are parameters to be estimated; m is the positive real number that determines the number of angles of the Gielis curve. Most prior studies on the Gielis equation focused mainly on its applications. However, the Gielis equation can also generate a large number of shapes that are rotationally symmetric and axisymmetric when A = B and n2 = n3, interrelated with the parameter m, with the parameters n1 and n2 determining the shapes of the curves. In this paper, we prove the relationship between m and the rotational symmetry and axial symmetry of the Gielis curve from a theoretical point of view with the condition A = B, n2 = n3. We also set n1 and n2 to take negative real numbers rather than only taking positive real numbers, then classify the curves based on extremal properties of r(φ) at φ = 0, π/m when n1 and n2 are in different intervals, and analyze how n1, n2 precisely affect the shapes of Gielis curves.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000904525700001 Publication Date 2022-11-23  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2073-8994 ISBN Additional Links UA library record; WoS full record  
  Impact Factor 2.7 Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: 2.7  
  Call Number UA @ admin @ c:irua:191860 Serial 7301  
Permanent link to this record
 

 
Author Gielis, J.; Tavkhelidze, I.; Ricci, P.E. url  openurl
  Title Generalized Möbius-Listing bodies and the heart Type A3 Journal article
  Year 2023 Publication (down) Sn – 2247-689x Abbreviated Journal  
  Volume 13 Issue 2 Pages 58-70  
  Keywords A3 Journal article; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract Generalized Möbius-Listing surfaces and bodies generalize Möbius bands, and this research was motivated originally by solutions of boundary value problems. Analogous to cutting of the original Möbius band, for this class of surfaces and bodies, results have been obtained when cutting such bodies or surfaces. The results can be applied in a wide range of fields in the natural science, and here we propose how they can serve as a model for the heart and the circulatory system.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos http://rjm-cs.ro/2023v13i2_7.pdf#page=1 Publication Date  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record; http://rjm-cs.ro/2023v13i2_7.pdf#page=1  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:200773 Serial 9043  
Permanent link to this record
 

 
Author Gielis, J.; Grigolia, R. url  openurl
  Title Lamé curves and Rvachev's R-functions Type A3 Journal article
  Year 2022 Publication (down) Sn – 1512-0066 Abbreviated Journal  
  Volume 37 Issue Pages 1-4  
  Keywords A3 Journal article; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract Gielis transformations are a generalization of Lame curves. To combine domains, we can make use of the natural alliance between Lame's work and Rvachev's R-functions. A logical next step is the extension to n-valued logic dening dierent partitions.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ admin @ c:irua:189316 Serial 7178  
Permanent link to this record
 

 
Author Tavkhelidze, I.; Gielis, J.; Pinelas, S. file  openurl
  Title About some methods of analytic representation and classification of a wide set of geometric figures with “complex” configuration Type A3 Journal article
  Year 2020 Publication (down) Sn – 1512-0066 Abbreviated Journal  
  Volume 34 Issue Pages 81-84  
  Keywords A3 Journal article; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ admin @ c:irua:174475 Serial 7406  
Permanent link to this record
 

 
Author Gielis, J.; Tavkhelidze, I. file  openurl
  Title The Mӧbius phenomenon in Generalized Mӧbius-Listing bodies with cross sections of odd and even polygons Type A3 Journal article
  Year 2020 Publication (down) Sn – 1512-0066 Abbreviated Journal  
  Volume 34 Issue Pages 23-26  
  Keywords A3 Journal article; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access  
  Notes Approved Most recent IF: NA  
  Call Number UA @ admin @ c:irua:174474 Serial 8257  
Permanent link to this record
 

 
Author Tavkhelidze, I.; Gielis, J. pdf  openurl
  Title The process of cutting GMLmn bodies with dm-knives Type A3 Journal article
  Year 2018 Publication (down) Sn – 1512-0066 Abbreviated Journal  
  Volume 32 Issue Pages 67-70  
  Keywords A3 Journal article; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:159971 Serial 8417  
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Author Tavkhelidze, I.; Gielis, J. openurl 
  Title Structure of the dm knives and process of cutting of GML(man) or GRT(man) bodies Type A3 Journal article
  Year 2019 Publication (down) Sn – 1512-0066 Abbreviated Journal  
  Volume 33 Issue Pages  
  Keywords A3 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Additional Links UA library record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:164897 Serial 8588  
Permanent link to this record
 

 
Author Gielis, J. pdf  doi
openurl 
  Title Double helix of phyllotaxis : analysis of the geometric model of plant morphogenesis, by Boris Rozin Type Review
  Year 2021 Publication (down) Quarterly Review Of Biology Abbreviated Journal Q Rev Biol  
  Volume 96 Issue 2 Pages 139-140  
  Keywords Review; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos Publication Date 2021-05-19  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0033-5770; 1539-7718 ISBN Additional Links UA library record  
  Impact Factor 4.25 Times cited Open Access Not_Open_Access  
  Notes Approved Most recent IF: 4.25  
  Call Number UA @ admin @ c:irua:178829 Serial 7824  
Permanent link to this record
 

 
Author Mescia, L.; Lamacchia, C.M.; Chiapperino, M.A.; Bia, P.; Gielis, J.; Caratelli, D. pdf  doi
openurl 
  Title Design of irregularly shaped lens antennas including supershaped feed Type P1 Proceeding
  Year 2019 Publication (down) Progress in Electromagnetic Research Symposium (PIERS) T2 – 2019 PhotonIcs & Electromagnetics Research Symposium – Spring (PIERS-Spring), 17-20 June, 2019, Rome, Italy Abbreviated Journal  
  Volume Issue Pages 169-173  
  Keywords P1 Proceeding; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract A new class of irregularly shaped dielectric lens antennas with a supershaped microstrip antenna feeder is presented and detailed in this work. The surface of the lens antenna and the feeder shape have been modelled by using the three and two-dimensional Gielis formula, respectively. The antenna design has been carried out by integrating an home-made software tool with the CST Microwave Studio®. The radiation properties of the whole antenna system have been evaluated using a dedicated high-frequency technique based on the tube tracing approximation. Moreover, the effects due to the multiple internal reflections have been properly modeled. The proposed model was applied to study unusual and complex lens antenna systems with the aim to design special radiation characteristics.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000550769300021 Publication Date 2020-03-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 978-1-72813-403-1; 978-1-72813-404-8; 978-1-72813-403-1 ISBN Additional Links UA library record; WoS full record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:169169 Serial 7766  
Permanent link to this record
 

 
Author Mescia, L.; Chiapperino, M.A.; Bia, P.; Lamacchia, C.M.; Gielis, J.; Caratelli, D. pdf  doi
openurl 
  Title Multiphysics modelling of membrane electroporation in irregularly shaped cells Type P1 Proceeding
  Year 2019 Publication (down) Progress in Electromagnetic Research Symposium (PIERS) T2 – 2019 PhotonIcs & Electromagnetics Research Symposium – Spring (PIERS-Spring), 17-20 June 2019, Rome, Italy Abbreviated Journal  
  Volume Issue Pages 2992-2998  
  Keywords P1 Proceeding; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract Electroporation is a non-thermal electromagnetic phenomenon widely used in medical diseases treatment. Different mathematical models of electroporation have been proposed in literature to study pore evolution in biological membranes. This paper presents a nonlinear dispersive multiphysic model of electroporation in irregular shaped biological cells in which the spatial and temporal evolution of the pores size is taken into account. The model solves Maxwell and asymptotic Smoluchowski equations and it describes the dielectric dispersion of cell media using a Debye-based relationship. Furthermore, the irregular cell shape has been modeled using the Gielis superformula. Taking into account the cell in mitosis phase, the electroporation process has been studied comparing the numerical results pertaining the model with variable pore radius with those in which the pore radius is supposed constant. The numerical analysis has been performed exposing the biological cell to a rectangular electric pulse having duration of 10 μs. The obtained numerical results highlight considerable differences between the two different models underling the need to include into the numerical algorithm the differential equation modeling the spatial and time evolution of the pores size.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000550769302159 Publication Date 2020-03-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 978-1-72813-404-8; 978-1-72813-403-1 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:169170 Serial 8288  
Permanent link to this record
 

 
Author Mescia, L.; Chiapperino, M.A.; Bia, P.; Lamacchia, C.M.; Gielis, J.; Caratelli, D. pdf  doi
openurl 
  Title Relevance of the cell membrane modelling for accurate analysis of the pulsed electric field-induced electroporation Type P1 Proceeding
  Year 2019 Publication (down) Progress in Electromagnetic Research Symposium (PIERS) T2 – 2019 PhotonIcs & Electromagnetics Research Symposium – Spring (PIERS-Spring), 17-20 June 2019, Rome, Italy Abbreviated Journal  
  Volume Issue Pages 2985-2991  
  Keywords P1 Proceeding; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract In this work, a nonlinear dispersive multiphysic model based on Maxwell and asymptotic Smoluchowsky equations has been developed to analyze the electroporation phenomenon induced by pulsed electric field on biological cells. The irregular plasma membrane geometry has been modeled by incorporating in the numerical algorithm the Gielis superformula as well as the dielectric dispersion of the plasma membrane has been modeled using the multi-relaxation Debye-based relationship. The study has been carried out with the aim to compare our model implementing a thin plasma membrane with the simplified model in which the plasma membrane is modeled as a distributed impedance boundary condition. The numerical analysis has been performed exposing the cell to external electric pulses having rectangular shapes. By an inspection of the obtained results, significant differences can be highlighted between the two models confirming the need to incorporate the effective thin membrane into the numerical algorithm to well predict the cell response to the pulsed electric fields in terms of transmembrane voltages and pore densities, especially when the cell is exposed to external nanosecond pulses.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000550769302158 Publication Date 2020-03-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 978-1-72813-404-8; 978-1-72813-403-1 ISBN Additional Links UA library record; WoS full record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:169171 Serial 8469  
Permanent link to this record
 

 
Author Gielis, J.; Caratelli, D.; Fougerolle, Y.; Ricci, P.E.; Tavkelidze, I.; Gerats, T. url  doi
openurl 
  Title Universal natural shapes : from unifying shape description to simple methods for shape analysis and boundary value problems Type A1 Journal article
  Year 2012 Publication (down) PLoS ONE Abbreviated Journal  
  Volume 7 Issue 9 Pages e29324-11  
  Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract Gielis curves and surfaces can describe a wide range of natural shapes and they have been used in various studies in biology and physics as descriptive tool. This has stimulated the generalization of widely used computational methods. Here we show that proper normalization of the Levenberg-Marquardt algorithm allows for efficient and robust reconstruction of Gielis curves, including self-intersecting and asymmetric curves, without increasing the overall complexity of the algorithm. Then, we show how complex curves of k-type can be constructed and how solutions to the Dirichlet problem for the Laplace equation on these complex domains can be derived using a semi-Fourier method. In all three methods, descriptive and computational power and efficiency is obtained in a surprisingly simple way.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000309517500001 Publication Date 2012-09-30  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1932-6203 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:102202 Serial 8711  
Permanent link to this record
 

 
Author Wang, L.; Miao, Q.; Niinemets, Ü.; Gielis, J.; Shi, P. url  doi
openurl 
  Title Quantifying the variation in the geometries of the outer rims of corolla tubes of Vinca major L Type A1 Journal article
  Year 2022 Publication (down) Plants Abbreviated Journal  
  Volume 11 Issue 15 Pages 1987-12  
  Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract Many geometries of plant organs can be described by the Gielis equation, a polar coordinate equation extended from the superellipse equation, . Here, r is the polar radius corresponding to the polar angle φ; m is a positive integer that determines the number of angles of the Gielis curve when φ ∈ [0 to 2π); and the rest of the symbols are parameters to be estimated. The pentagonal radial symmetry of calyxes and corolla tubes in top view is a common feature in the flowers of many eudicots. However, prior studies have not tested whether the Gielis equation can depict the shapes of corolla tubes. We sampled randomly 366 flowers of Vinca major L., among which 360 had five petals and pentagonal corolla tubes, and six had four petals and quadrangular corolla tubes. We extracted the planar coordinates of the outer rims of corolla tubes (in top view) (ORCTs), and then fitted the data with two simplified versions of the Gielis equation with k = 1 and m = 5: (Model 1), and (Model 2). The adjusted root mean square error (RMSEadj) was used to evaluate the goodness of fit of each model. In addition, to test whether ORCTs are radially symmetrical, we correlated the estimates of n2 and n3 in Model 1 on a log-log scale. The results validated the two simplified Gielis equations. The RMSEadj values for all corolla tubes were smaller than 0.05 for both models. The numerical values of n2 and n3 were demonstrated to be statistically equal based on the regression analysis, which suggested that the ORCTs of V. major are radially symmetrical. It suggests that Model 1 can be replaced by the simpler Model 2 for fitting the ORCT in this species. This work indicates that the pentagonal or quadrangular corolla tubes (in top view) can both be modeled by the Gielis equation and demonstrates that the pentagonal or quadrangular corolla tubes of plants tend to form radial symmetrical geometries during their development and growth.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000839115100001 Publication Date 2022-08-01  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2223-7747 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: NA  
  Call Number UA @ admin @ c:irua:189315 Serial 7200  
Permanent link to this record
 

 
Author Yao, W.; Niinemets, Ü.; Yao, W.; Gielis, J.; Schrader, J.; Yu, K.; Shi, P. url  doi
openurl 
  Title Comparison of two simplified versions of the Gielis equation for describing the shape of bamboo leaves Type A1 Journal article
  Year 2022 Publication (down) Plants Abbreviated Journal  
  Volume 11 Issue 22 Pages 3058-11  
  Keywords A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract Bamboo is an important component in subtropical and tropical forest communities. The plant has characteristic long lanceolate leaves with parallel venation. Prior studies have shown that the leaf shapes of this plant group can be well described by a simplified version (referred to as SGE-1) of the Gielis equation, a polar coordinate equation extended from the superellipse equation. SGE-1 with only two model parameters is less complex than the original Gielis equation with six parameters. Previous studies have seldom tested whether other simplified versions of the Gielis equation are superior to SGE-1 in fitting empirical leaf shape data. In the present study, we compared a three-parameter Gielis equation (referred to as SGE-2) with the two-parameter SGE-1 using the leaf boundary coordinate data of six bamboo species within the same genus that have representative long lanceolate leaves, with >300 leaves for each species. We sampled 2000 data points at approximately equidistant locations on the boundary of each leaf, and estimated the parameters for the two models. The root–mean–square error (RMSE) between the observed and predicted radii from the polar point to data points on the boundary of each leaf was used as a measure of the model goodness of fit, and the mean percent error between the RMSEs from fitting SGE-1 and SGE-2 was used to examine whether the introduction of an additional parameter in SGE-1 remarkably improves the model’s fitting. We found that the RMSE value of SGE-2 was always smaller than that of SGE-1. The mean percent errors among the two models ranged from 7.5% to 20% across the six species. These results indicate that SGE-2 is superior to SGE-1 and should be used in fitting leaf shapes. We argue that the results of the current study can be potentially extended to other lanceolate leaf shapes.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000887783400001 Publication Date 2022-11-14  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2223-7747 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: NA  
  Call Number UA @ admin @ c:irua:191859 Serial 7289  
Permanent link to this record
 

 
Author Huang, L.; Ratkowsky, D.A.; Hui, C.; Gielis, J.; Lian, M.; Shi, P. url  doi
openurl 
  Title Inequality measure of leaf area distribution for a drought-tolerant landscape plant Type A1 Journal article
  Year 2023 Publication (down) Plants Abbreviated Journal  
  Volume 12 Issue 17 Pages 3143-11  
  Keywords A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract Measuring the inequality of leaf area distribution per plant (ILAD) can provide a useful tool for quantifying the influences of intra- and interspecific competition, foraging behavior of herbivores, and environmental stress on plants’ above-ground architectural structures and survival strategies. Despite its importance, there has been limited research on this issue. This paper aims to fill this gap by comparing four inequality indices to measure ILAD, using indices for quantifying household income that are commonly used in economics, including the Gini index (which is based on the Lorenz curve), the coefficient of variation, the Theil index, and the mean log deviation index. We measured the area of all leaves for 240 individual plants of the species Shibataea chinensis Nakai, a drought-tolerant landscape plant found in southern China. A three-parameter performance equation was fitted to observations of the cumulative proportion of leaf area vs. the cumulative proportion of leaves per plant to calculate the Gini index for each individual specimen of S. chinensis. The performance equation was demonstrated to be valid in describing the rotated and right shifted Lorenz curve, given that >96% of root-mean-square error values were smaller than 0.004 for 240 individual plants. By examining the correlation between any of the six possible pairs of indices among the Gini index, the coefficient of variation, the Theil index, and the mean log deviation index, the data show that these indices are closely related and can be used interchangeably to quantify ILAD.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001065193100001 Publication Date 2023-08-31  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2223-7747 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access OpenAccess  
  Notes Approved Most recent IF: NA  
  Call Number UA @ admin @ c:irua:199564 Serial 8886  
Permanent link to this record
 

 
Author Gao, J.; Huang, W.; Gielis, J.; Shi, P. url  doi
openurl 
  Title Plant morphology and function, geometric morphometrics, and modelling : decoding the mathematical secrets of plants Type Editorial
  Year 2023 Publication (down) Plants Abbreviated Journal  
  Volume 12 Issue 21 Pages 3724-2  
  Keywords Editorial; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 001103336500001 Publication Date 2023-10-30  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2223-7747 ISBN Additional Links UA library record; WoS full record  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:201173 Serial 9072  
Permanent link to this record
 

 
Author Fougerolle, Y.D.; Truchetet, F.; Demonceaux, C.; Gielis, J. pdf  doi
openurl 
  Title A robust evolutionary algorithm for the recovery of rational Gielis curves Type A1 Journal article
  Year 2013 Publication (down) Pattern recognition Abbreviated Journal  
  Volume 46 Issue 8 Pages 2078-2091  
  Keywords A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL)  
  Abstract Gielis curves (GC) can represent a wide range of shapes and patterns ranging from star shapes to symmetric and asymmetric polygons, and even self intersecting curves. Such patterns appear in natural objects or phenomena, such as flowers, crystals, pollen structures, animals, or even wave propagation. Gielis curves and surfaces are an extension of Lamé curves and surfaces (superquadrics) which have benefited in the last two decades of extensive researches to retrieve their parameters from various data types, such as range images, 2D and 3D point clouds, etc. Unfortunately, the most efficient techniques for superquadrics recovery, based on deterministic methods, cannot directly be adapted to Gielis curves. Indeed, the different nature of their parameters forbids the use of a unified gradient descent approach, which requires initial pre-processings, such as the symmetry detection, and a reliable pose and scale estimation. Furthermore, even the most recent algorithms in the literature remain extremely sensitive to initialization and often fall into local minima in the presence of large missing data. We present a simple evolutionary algorithm which overcomes most of these issues and unifies all of the required operations into a single though efficient approach. The key ideas in this paper are the replacement of the potential fields used for the cost function (closed form) by the shortest Euclidean distance (SED, iterative approach), the construction of cost functions which minimize the shortest distance as well as the curve length using R-functions, and slight modifications of the evolutionary operators. We show that the proposed cost function based on SED and R-function offers the best compromise in terms of accuracy, robustness to noise, and missing data.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Wos 000317944800002 Publication Date 2013-01-29  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-3203 ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor Times cited Open Access  
  Notes Approved no  
  Call Number UA @ admin @ c:irua:107181 Serial 8485  
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