scholarly journals 3D Structural Model and Visualization of Blood Vessels Based on L-System

2021 ◽  
Vol 18 (24) ◽  
pp. 1407
Author(s):  
Siriprapa Ritraksa ◽  
Khamron Mekchay
Keyword(s):  
Blood Vessels ◽  
Structural Model ◽  
Future Research ◽  
Total Blood ◽  
Murray's Law ◽  
Murray’S Law ◽  
L System ◽  
Angle Condition ◽  
System L ◽  
Additional Assumptions

The insight in structures of the blood vessels is a basis for study of blood flows to help understanding the abnormalities of blood vessels that can cause vascular diseases. Basic concept used for constructing structures of blood vessels in organs is arterial branching, which is usually characterized by fractal similarity in the bifurcation pattern. In this work, the concept of Lindenmayer system (L-system) is modified for three-dimensional (3D) tree-like structures to model structures of blood vessels in organs, and then, applied to construct and visualize structural blood vessels via our software created based on openGL and Lazarus program. The structure of blood vessels is constructed based on the physiological law of arterial branching proposed Murray (Murray’s law) under additional assumptions and constraints such as the spreading of blood vessels to cover all directions, the angle condition and the non-overlapping vessels condition. The concept is applied to simulate structures of blood vessels in 3 study cases, including symmetric arterial branching, non-symmetric arterial branching and structure of blood vessel on different domains. The results of structures of blood vessels generated from all cases are measured based on the number of segments, the total blood volume and the fractal dimension. The results of modeling and simulation in this work are illustrated by comparing with other results appeared literature. Moreover, the constructed structures of the blood vessels based on this 3D L-system could be useful for future research such as blood flow, pressure and other properties involving in structures of blood vessels in different organs of human and animals. HIGHLIGHTS A new 3D L-system is developed based on directional vectors for construction of 3D tree-like structures such as structures of blood vessels The model of structures of blood vessels is constructed based on the physiological laws of arterial branching (Murray’s law) with additional assumptions on the spreading of blood vessels, the angle condition, and the non-overlapping of blood vessels Algorithm and software are developed based on L-system to simulate and visualize 3D structures of blood vessels GRAPHICAL ABSTRACT

scholarly journals Hierarchy in materials for maximized efficiency

2020 ◽  
Vol 7 (11) ◽  
pp. 1626-1630
Author(s):  
Li-Hua Chen ◽  
Yu Li ◽  
Bao-Lian Su
Keyword(s):  
Design Theory ◽  
Materials Design ◽  
Research Direction ◽  
Future Research ◽  
Future Research Direction ◽  
Murray's Law ◽  
Murray’S Law ◽  
The Future

This perspective article gives the future research direction on the application of the generalized Murray's law for the design of porous hierarchy in materials and the establishment of a general materials design theory 'law of hierarchy' taking four types of hierarchy into account.

scholarly journals Modelling of retinal vasculature based on genetically tuned parametric L-system

2018 ◽  
Vol 5 (5) ◽  
pp. 171639 ◽  
Author(s):  
Seyed Mohammad Ali Aghamirmohammadali ◽  
Ramin Bozorgmehry Boozarjomehry ◽  
Mohammad Abdekhodaie
Keyword(s):  
Inverse Problem ◽  
Blood Vessels ◽  
Feature Matching ◽  
Image Data ◽  
Retinal Vasculature ◽  
L System ◽  
Retinal Blood Vessels ◽  
System L ◽  
Generating Tree ◽  
Special Instance

Structures of retinal blood vessels are of great importance in diagnosis and treatment of diseases that affect the eyes. Parametric Lindenmayer system (L-system) is one of the powerful rule-based methods that has a great capability for generating tree-like structures using simple rewriting rules. In this study, a novel framework, which can be used to model the retinal vasculature based on available images, has been proposed. This framework presents a solution to special instance of a general open problem, the L-system inverse problem, in which L-system rules should be obtained based on images representing a particular tree-like structure. In this study, genetic algorithm with a novel objective function based on feature matching and an L-system grammar comparison has been used along with nonlinear regression to solve the parametric L-system inverse problem. The resulting L-system growth rules have been employed to predict inaccessible vascular branches. Graphical and quantitative comparison between model results and target structures of different case studies reveals that the proposed framework can be used to generate the structure of retinal blood vessels accurately. Even in the cases lacking sufficient image data, it can provide acceptable predictions.

Assessment of Teacher Attitudes Toward Inclusion of Students with Disabilities: A Confirmatory Factor Analysis

1997 ◽  
Vol 14 (1) ◽  
pp. 51-64 ◽  
Author(s):  
Georgios D. Sideridis ◽  
Judy P. Chandler
Keyword(s):  
Physical Education ◽  
Music Education ◽  
Students With Disabilities ◽  
Structural Equation ◽  
Structural Model ◽  
Equation Modeling ◽  
Future Research ◽  
Physical Education Teachers ◽  
The Status ◽  
Fit Index

The Teacher Integration Attitudes Questionnaire (TIAQ) was developed in order to assess the attitudes and beliefs of teachers (n = 110) with regard to the inclusion of students with disabilities in regular education settings. Using Structural Equation Modeling, the final structural model of the TIAQ comprised four constructs, namely, “Skills,” “Benefits,” “Acceptance,” and “Support.” The final model was fully supported by the derivation sample of music education teachers (n = 54) and produced a Comparative Fit Index (CFI = 1.00). The replication sample of physical education teachers (n = 56) partially supported the generality of the TIAQ, (CFI = .844). Further, the internal consistency properties of the TIAQ (Cronbach’s alpha was .77 for both samples) were satisfactory. We conclude that the psychometric properties of the TIAQ were adequate, and it can be used as a valid assessment in evaluating the status of inclusion for students with disabilities as perceived by music education and physical education teachers. However, future research is needed to support its generality with other groups of teachers and professionals.

scholarly journals The role of self-control, self-efficacy, metacognition, and motivation in predicting school achievement

Psihologija ◽  
2019 ◽  
Vol 52 (1) ◽  
pp. 35-52
Author(s):  
Vladimir Dzinovic ◽  
Rajka Djevic ◽  
Ivana Djeric
Keyword(s):  
Self Efficacy ◽  
Structural Model ◽  
School Achievement ◽  
Self Regulation ◽  
Self Control ◽  
Future Research ◽  
Self Regulated Learning ◽  
Regulated Learning ◽  
Eighth Grade Students

Self-control and self-regulated learning refer to those processes and strategies whereby individuals exert agency in facing educational demands. This study tested a structural model which predicts that self-control has direct effect on school achievement, as well as mediated by metacognitive self-regulation, academic self-efficacy, and regulatory motivational styles as the variables related to self-regulated learning. The research was carried out on a stratified random sample of 575 eighth grade students. It was shown that the effect of self-control on achievement is mediated by self-efficacy. In other words, students who have heightened selfcontrol and believe in their own ability to meet school demands will be successful in school regardless of the complexity of their learning or whether they are autonomously motivated. The implications of such a finding were considered, as well as the limitations of the research and the indications for future research.

The effect of clustering on competitiveness improvement in Hebron

2017 ◽  
Vol 28 (5) ◽  
pp. 631-654 ◽  
Author(s):  
Ibrahim M. Awad ◽  
Alaa A. Amro
Keyword(s):  
Structural Equation ◽  
Structural Model ◽  
Model Building ◽  
Measurement Model ◽  
Background Information ◽  
Equation Modeling ◽  
Future Research ◽  
Research Model ◽  
Content Type ◽  
The Impact

Purpose The purpose of this paper is to map the cluster in the leather and shoes sector for improving the competitiveness of the firms. Toward this end, the study is organized to examine the impact of clustering on competitiveness improvement. The influence of competitive elements and performance (Porter’s diamond) and balanced score card was utilized. Design/methodology/approach A random sample of 131 respondents was chosen during the period from May 2016 to July 2016. A structural equation modeling (SEM) analysis was applied to investigate the research model. This approach was chosen because of its ability to test casual relationships between constructs with multiple measurement items. Researchers proposed a two-stage model-building process for applying SEM. The measurement model was first examined for instrument validation, followed by an analysis of the structural model for testing associations hypothesized by the research model. Findings The main findings show that there is a unidirectional causal relationship between improvements of performance and achieve competitiveness and also reveal that the Palestinian shoes and leather cluster sector is vital and strong, and conclude that clustering can achieve competitiveness for small- and medium-sized enterprises. Research limitations/implications Future research can examine the relationship between clustering and innovation. The effect of clustering using other clustering models other than Porter’s model is advised to be used for future research. Practical implications The relationships among clustering and competitiveness may provide a practical clue to both, policymakers and researchers on how cluster enhances economic firms such as a skilled workforce, research, development capacity, and infrastructure. This is likely to create assets such as trust, synergy, collaboration and cooperation for improved competitiveness. Originality/value The findings of this study provide background information that can simultaneously be used to analyze relationships among factors of innovation, customer’s satisfaction, internal business and financial performance. This study also identified several essential factors in successful firms, and discussed the implications of these factors for developing organizational strategies to encourage and foster competitiveness.

Identifikasi Hambatan Penerapan Lean di Usaha Kecil dan Menengah (UKM)

2021 ◽  
Vol 4 (2) ◽  
pp. 107-124
Author(s):  
Mochammad Rifky Pamungkas ◽  
Erna Maulina ◽  
Margo Purnomo
Keyword(s):  
Structural Model ◽  
Small And Medium Enterprises ◽  
Future Research ◽  
Small Contribution ◽  
Lean Implementation ◽  
Study Approach ◽  
Management Commitment ◽  
Medium Enterprises ◽  
The City

Today's world competition has increased the pressure on Small and Medium Enterprises (SMEs) to adopt lean implementations. The purpose of this study is to make a small contribution by exploring the Lean Implementation Barrier (LIB) in SMEs through three case studies of SMEs in the city of Bandung. A case study approach is used and followed by the Interpretative Structural Model (ISM) in order to see the inter-LIB relationship. The results of this study indicate that lack of management commitment and leadership, lack of employee involvement and lack of resources are the main obstacles to lean implementation in SMEs in Indonesia. Moreover, poor communication among various levels within the company and inadequate dissemination of knowledge about the benefits of lean also create barriers to lean implementation. The implication of this research is to strengthen and expand information related to research on the application of lean in SMEs, especially the results of the identified barriers that can assist SMEs in implementing lean or future research in developing and identifying barriers to implementing lean in SMEs.

scholarly journals Perceived Confidence and Quality: Perception of Employers Towards Fresh Graduates: a Study in Malaysia

2018 ◽  
Vol 7 (3.21) ◽  
pp. 437
Author(s):  
Irza Hanie Abu Samah ◽  
Aidanazima Abashah ◽  
Saraih Ummi Naiemah
Keyword(s):  
Human Resource ◽  
Manufacturing Industry ◽  
Structural Model ◽  
Data Gathering ◽  
Measurement Model ◽  
Partial Least Square ◽  
Least Square ◽  
Future Research ◽  
Resource Officers ◽  
Human Resource Officers

Graduates quality has become a major issue recently especially in today’s scenario. Graduates quality can be varying when it perceived by employers. Different sector of industry has different standard of quality. The interpretation of employers towards graduates counts the job placement of graduates. It is hard to standardized quality across industries. Several attributes show that competence relatedness and autonomy do influence the quality of graduates. A quantitative method was used in this study for data gathering. All items were using 10-point likert scale. The content validity of this questionnaire were reviewed by five human resource professionals, and Cronbach alpha for each item is more than 0.75 which is acceptable. Questionnaires were given to the human resource officers in the company through email. Convenient sampling was applied in this study for data collection. 50 questionnaires were distributed across manufacturing industry and services industry in Malaysia. Using Partial least square to analyze the data, this study found out that competence in communication is the same criteria which majority across industries are seeking upon graduates. Therefore, Industries that involved are manufacturing (34.38%) and services (65.63%).  Measurement model and structural model were assessed to see the relationship. It shows that perception on competence has most influenced towards quality (AVE=0.849, R2=0.734=Q2=0.443).  This study concludes that employers around the world are looking at similar attribute on graduate’s competence. This study also warrants a future research, whereby researcher could get more sample size and by doing sample which involves employers, graduates and educators.

Graph-Based Interpretation of L-System Encodings Toward Aeroelastic Topology Optimization of a Morphing Airfoil in Supersonic Flow

2019 ◽  
Author(s):  
Brent R. Bielefeldt ◽  
Darren J. Hartl ◽  
Joshua D. Hodson ◽  
Gregory W. Reich ◽  
Philip S. Beran ◽  
...  
Keyword(s):  
Supersonic Flow ◽  
Performance Criteria ◽  
Preliminary Design ◽  
Structural Topology ◽  
L System ◽  
Design Variables ◽  
System L ◽  
Interpretation Algorithm ◽  
Actuation Systems ◽  
Reconfigurable Structures

Abstract This work details the preliminary design of a morphing airfoil in supersonic flow using evolutionary design principles. The structural topology of the airfoil includes a fixed outer mold line, fixed spars, and designable internal stiffeners and actuators. The designable components are generated using a bio-inspired model known as a Lindenmayer System (L-System), which encodes design variables and governs the development of a structural topology when coupled with an interpretation algorithm. Here, we utilize a graph-based interpretation scheme known as Spatial Interpretation for the Development of Reconfigurable Structures (SPIDRS), which has been shown to effectively explore the mechanism design space using a limited number of design variables. The optimization process behind this preliminary design problem is discussed, and optimal airfoil topologies capable of meeting specified aerodynamic performance criteria are presented in hopes of gaining a better understanding of how actuation systems could be integrated into the next generation of aircraft.

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