bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Using Mobile Devices on Students' Performance in Writing
Authors: Patronis Marielle
Published: July 2016

The number of projects exploring the potential of mobile device-facilitated learning is steadily growing in higher education, prompted, in part, by the use of mobile technology in the work place. The use of mobile devices has expanded from short-term trials on a small scale to large-scale integration in educational settings from primary to higher education. With this increase, the use of textual-based communication has also increased. Hence, the mode of writing faces a new environment from printed text to the digital. However, there remains a lack of analysis that brings together the findings of the impact of using mobile devices on students' performance in academic writing. Consequently, the aim of this chapter is to provide an overview of how mobile devices impact students' performance in writing along with recommendations for possible future pedagogical uses of mobile technologies. The chapter builds on a pilot study conducted in spring 2014 at a university in Dubai, UAE, which explored the effect of using the iPad on learners' writing performance.
Review of Data Mining Techniques and Parameters for Recommendation of Effective Adaptive E-Learning System
Authors: Mahajan Renuka
Published: July 2016

This chapter revolves around the synthesis of three research areas- data mining, personalization, recommendation systems and adaptive e-Learning systems. It also introduces a comprehensive list of parameters, extricated by reviewing the existing research intensity during the period of 2000 to October 2014, for understanding what should be essential parameters for adapting an e-learning. In general, we can consider and answer few questions to answer this body of literature ‘what' can be adapted? What can we adapt to? How do we adapt? This review tries to answer on ‘what' can be adapted. Thus, it advances earlier personalization studies. The gaps in the previous studies in building adaptive e-learning systems were also reviewed. It can help in designing new models for adaptation and formulating novel recommender system techniques. This will provide a foundation to industry experts and scientists for future research in adaptive e-learning.
History and Overview of the Recommender Systems
Authors: M. Venkatesan , K. Thangadurai
Published: July 2016

This Chapter analyzes the recommender systems, their history and its framework in brief. The current generation of filtering techniques in recommendation methods can be broadly classified into the following five categories. Techniques used in these categories are discussed in detail. Data mining algorithms techniques are implemented in recommender systems to filters user data ratings. Area of application of Recommender Systems gives broad idea and such as how it gives impact and why it is used in the e-commerce, Online Social Networks (OSN), and so on. It has shifted the core of Internet applications from devices to users. In this chapter, issues and recent research in recommender system are also discussed.
Collaborative and Clustering Based Strategy in Big Data
Authors: Jain Arushi , Bhatnagar Vishal , Sharma Pulkit
Published: July 2016

There is a proliferation in the amount of data generated and its volume, which is going to persevere for many coming years. Big data clustering is the exercise of taking a set of objects and dividing them into groups in such a way that the objects in the same groups are more similar to each other according to a certain set of parameters than to those in other groups. These groups are known as clusters. Cluster analysis is one of the main tasks in the field of data mining and is a commonly used technique for statistical analysis of data. While big data collaborative filtering defined as a technique that filters the information sought by the user and patterns by collaborating multiple data sets such as viewpoints, multiple agents and pre-existing data about the users' behavior stored in matrices. Collaborative filtering is especially required when a huge data set is present.
Statistical Relational Learning for Collaborative Filtering a State-of-the-Art Review
Authors: Nishani Lediona , Biba Marenglen
Published: July 2016

People nowadays base their behavior by making choices through word of mouth, media, public opinion, surveys, etc. One of the most prominent techniques of recommender systems is Collaborative filtering (CF), which utilizes the known preferences of several users to develop recommendation for other users. CF can introduce limitations like new-item problem, new-user problem or data sparsity, which can be mitigated by employing Statistical Relational Learning (SRLs). This review chapter presents a comprehensive scientific survey from the basic and traditional techniques to the-state-of-the-art of SRL algorithms implemented for collaborative filtering issues. Authors provide a comprehensive review of SRL for CF tasks and demonstrate strong evidence that SRL can be successfully implemented in the recommender systems domain. Finally, the chapter is concluded with a summarization of the key issues that SRLs tackle in the collaborative filtering area and suggest further open issues in order to advance in this field of research.
Facilitating Knowledge Sharing on Social Media for Students of International Relations and Conflict Studies in Nigeria
Authors: Okolie-Osemene James
Published: July 2016

This chapter has examined ways of facilitating knowledge sharing for the benefit of students of international relations and conflict studies in Nigerian universities. It is evident that tertiary institutions' students of the 21st Century cannot study now without the use of social media which serves as a platform for information sharing and knowledge production. It is a medium through which knowledge is transferred to users by think tanks and organisations across the world. Given that not only students benefit, people from all walks of life are not also left out as social networks record large number of users daily. This explains how social media serves as data bank for scholars and why students now need to continuously search to find related materials on social media. Using qualitative data the author used observation method in the classroom setting in the University of Ibadan and Wellspring University, Benin City, Nigeria. It should be stated that the type of digital device used by students can as well determine their level of access to the social media in Nigeria. Observations show that social media is very relevant for students especially in the study and teaching of international relations and conflict studies given the number of global courses like new states in world politics, democracy and human rights, post-cold war politics, global refugee regimes, international law problems of peacemaking and peacekeeping, among others which all generate issues on daily basis that need to be shared as relevant academic materials for among students.
Towards a Model of Social Media Impacts on Cybersecurity Knowledge Transfer
Authors: Patnayakuni Nainika , Patnayakuni Ravi , Gupta Jatinder N. D.
Published: July 2016

Technical solutions to security have been suggested but found lacking and it has been recognized that security is a people issue as well, and behavioral research on information security is critical. Individual learning about cybersecurity is not formal and linear, but complex and network based. In this paper we develop a model of how social media characteristics impact cybersecurity knowledge transfer using technology threat avoidance theory. In developing the conceptual model we seek to answer the following questions. How do users discover cybersecurity knowledge on social media platforms? What are the platform and interaction characteristics that enable them to find cybersecurity knowledge and share this knowledge with others? In doing so we consider the impact of the threat and protection context on cybersecurity knowledge transfer which is different from knowledge transfer in the other contexts.
Foundations of Multimedia Information Processing
Authors: Das Bhattacharjee Anindita
Published: July 2016

It is easy to understand image and video stream by a human being but a computer can't understand them at all. For that reason there are several methods to make the computer to understand about the media it is being talked about. The following writing discusses about how to analyze a video or an image by using several methods like scene analysis, and shot boundary detection and analysis, frame analysis, hypermedia representation, segmentation of media. All of these are the representation of the whole media that have been fed as input and these representation outputs are used by computer by computer vision algorithm to process a video or image and give the expected results. The main focus of this writing is discussing how to use the above mentioned methods in any of the media video or image and extract the information required to represent the whole media under process.
Compressive Sensing for Biometric System
Authors: Thanki Rohit M. , Borisagar Komal R.
Published: July 2016

Biometric system is used by many institution, organization and industry for automatic recognition of person. One of the main reason for popularity of used for biometric system is that the ability of the system to identify between an authorized person and unauthorized person. There are many challenges associated with the biometric system such as designing of human recognition algorithm, compression of biometric templates, privacy and security of biometric templates in biometric systems. This chapter gives an application of Compressive Sensing (CS) theory for solutions of the above mentioned challenges in biometric systems. Recent research and trends in a biometric system indicated that many challenging of biometric system problems are being solved using Compressive Sensing (CS) theory and sparse representation algorithms. This chapter gives an overview of sparsity property of various image transforms and application of compressive sensing and sparse representation with regards to biometric image compression, biometric image recognition and biometric image protection.
Integration of Different Analytical Concepts on Multimedia Contents in Service of Intelligent Knowledge Extraction
Authors: Klepac Goran
Published: July 2016

This chapter will introduce methodology how to use analytical potential of multimedia contents like YouTube, Bing Videos or Vimeo for discovering behavioral consumer characteristics. Chapter will also show how to consolidate unstructured text data sources from blogs and Twitter with revealed knowledge from multimedia contents for better understanding consumer habits and needs. For this purposes Social Network Analysis will be used as well as text mining techniques on different internet data sources. Presented methodology has practical value where information about customer behavior, preferences and changes in preferences during different time periods is valuable information for campaign planning, campaign management and new product development. Presented methodology also captures different techniques for data crawling from different internet resources, as well as analytical consolidation of revealed results which aim is better understanding of client behavior.
Can We Induce a Cognitive Representation of a Prosthetic Arm by Means of Crossmodal Stimuli?
Authors: Franco Mateus , Ortiz Tiago V. , Amorim Henrique A. , Faber Jean
Published: July 2016

The ownership feeling of our body occurs mainly due to feedback responses in real-time from environment stimuli to our own body. These constant feedbacks induce a neuronal arrangement, generating a representative map and, consequently, an ownership and unity feeling, named as a body schema. Although there is a relative well knowing of the sensorial mapping about each part of our body, there are still several gaps about how the integration of all this representation is indeed accomplished. Many researchers have shown high rates of prosthesis non-acceptance due to different reasons. Here, the authors discuss an experimental protocol to induce optimally the ownership feeling associated with upper limb prosthesis, by means of a crossmodal vibro-tactile stimulation over the individual's body. The main hypothesis is that through this procedure the participant will extend their proprioception and achieve an ownership feeling of the prosthesis.
Cognitive Processes in the Reception of Interactive Short Film Script
Authors: Bieging Patricia , Busarello Raul Inácio
Published: July 2016

This chapter aims to present mental representations by seven audiovisual specialists on Sirena, the antagonist of a noir fictional story in a multilinear interactive short film script. To this end, a reception study was created with in-depth interviews with specialists after reading the script to discuss its several aspects. This approach is of qualitative character. The study was conducted between June and October 2015 in São Paulo, Brazil. It is possible to perceive that participants have interpreted the character differently in spite of its consistent build. We could verify that the mental representation of the antagonist was aided by the world-view and experience of each interviewed specialist, which has led to unique readings of the character.
Understanding How the Mind Works
Authors: Feitosa-Santana Claudia
Published: July 2016

The understanding of the inner workings of the mind are relevant to enhance curriculum achievements, therefore optimizing the professional practice in general and of the arts and design in particular. The recent birth of neuroscience as a transdisciplinary field poses a challenge to the curriculum and is yet to be included as an integral part of its core. The lessons taught by #TheDress viral Internet phenomenon are here discussed with the intention of enlightening the urgency of a popularization of neuroscience knowledge, from daily life to the professional practice, as a tool to explain how context and experience influence our perception. Along the same lines, the section “The Roots of Human Behavior” addresses the fundamental concept of human behavior and how our emotions were built by our genes, helping us understand basic and complex human choices. Finally, the section “The Neuroscience of Creativity” discusses the neural basis of creativity and its relation to intelligence by dissecting what neuroscience already knows about the development of creativity and how the work environment could foster creativity. The discussion of these topics in this chapter aims to enlighten readers of the importance of neuroscience knowledge in the curriculum and how the arts and design practices can benefit society to become more tolerant.
Efficient Development and Execution of Adaptable Online Games on Clouds
Authors: Meiländer Dominik , Gorlatch Sergei
Published: July 2016

Massively Multiplayer Online Games (MMOG) are a challenging class of applications: they combine high demands on real-time user interactivity and adaptability with the problem of an efficient and economic utilization of resources for the dynamically changing number of users. This chapter studies how MMOG can benefit from Cloud Computing with its Infrastructure-as-a-Service (IaaS) approach to cost-efficient leasing resources on demand. The chapter makes two major contributions: (1) a new lifecycle model for the development of adaptable MMOG expresses major design and execution aspects of Cloud-based MMOG, and (2) a resource management system RTF-RMS implements efficient load balancing for MMOG on Clouds. The authors illustrate how their lifecycle model and RTF-RMS system support the efficient development and execution of adaptable MMOG on Clouds and demonstrate the advantages of their approach in an experimental evaluation.
Emerging Technologies and Applications for Cloud-Based Gaming
Authors: Gopal Deverajan Ganesh , Kaushik Sekaran
Published: July 2016

Cloud computing technology has revolutionized the field of networks and the way of utilizing the resources remotely. In the gaming field this has changed the way of playing traditional games in relation to online on-demand available games which reduces the hassle at the clients' end. In order to play a game online, the game content is processed at the server end and rendered images are transmitted to the client's end. This makes the way of accessing easier and the game can be played even without the hardware or software required for the game. We review the cloud gaming architecture and the different types of streaming used by various cloud gaming platforms. Also, the issues and challenges with the service provider technologies used in the cloud gaming are discussed briefly.
Issues in On-Demand Cloud-Based Gaming Storage
Authors: Raj Ebin Deni , Babu L. D. Dhinesh
Published: July 2016

Cloud computing is the most utilized and evolving technology in the past few years and has taken computing to a whole new level such that even common man is receiving the benefits. The end user in cloud computing always prefers a cloud service provider which is efficient, reliable and best quality of service at the lowest possible price. A cloud based gaming system relieves the player from the burden of possessing high end processing and graphic units. The storage of games hosted in clouds using the latest technologies in cloud has been discussed in detail. The Quality of service of games hosted in cloud is the main focus of this chapter and we have proposed a mathematical model for the same. The various factors in dealing with the quality of service on cloud based games have been analyzed in detail. The quality of experience of cloud based games and its relation with quality of service has been derived. This chapter focuses on the various storage techniques, quality of experience factors and correlates the same with QoS in cloud based games.
Cloud-Based Gaming Services
Authors: Nag Shivangshu , Srivastava Vipul Kumar , Krishna Ragam Sai
Published: July 2016

This chapter talks about the latest technology being used for Cloud Gaming. It discusses about various aspects of this technology. The first part gives a brief introduction about what is actually cloud gaming and the ways in which it is implemented. The subsequent section talks about the various servers and units involved in the whole process. The next section talks about the importance of performance and efficiency in the Cloud Gaming system. There are various advantages of implementing such systems over the traditional gaming systems and of course every coin has two sides and thus there are various limitations of this technology which are discussed further in the chapter. What can be the new advancements and the future of the Cloud Gaming System has also been taken up in this chapter. Some case studies have also been included in this chapter to understand the various topics more clearly by analyzing the present scenarios and systems. The companies which offer cloud based gaming services have been discussed about to understand their technologies and implementation mechanisms.
A Need for Greater Collaboration
Authors: Sourial Mariette , Bamdas Jo Ann M. , Constanzo Angelica , Ishak Marina E.
Published: July 2016

Patient safety concerns have risen to such levels that multiple organizations and initiatives have been created to reduce hospital readmissions and medication errors in the United States healthcare system. Interprofessional education and collaborative practice (IPECP) has become a center of focus in healthcare education and the competency-based programs help health providers function more effectively as a team, train new university and college healthcare students to become ready for collaborative practice, and assist in making new policies and practices to improve today's healthcare system. This chapter provides a comprehensive overview of healthcare initiatives created to help lower hospital readmission rates and polypharmacy errors. These projects, programs, and initiatives optimize patient care while minimizing costs. With pharmacists, physicians, nurses, social workers, and other professionals and caregivers build better teams with improved communication and understanding each other's roles and responsibilities, the global healthcare system will overcome the numerous challenges.
Mental Illness, Youth, and Lessons from Residential Treatment Centers
Authors: Allison Krista , Allison Chris
Published: July 2016

This chapter explores mental illness in children and youth. In addition to understanding who is affected, this chapter seeks to express a holistic and comprehensive approach to physical, mental, and spiritual health. Research in each of these areas is discussed and relevant stories are presented from the authors' combined 10 years of experience in various residential treatment centers. Additionally, practical tools for families, educators, and clinicians are discussed. The purpose of this chapter is to increase awareness of the struggles mentally ill children endure and equip families, educators, and clinicians with practical tools for assisting children with mental illnesses.
Culture of Learning Cities
Authors: Dotson Ebbin , Hibbler Dan K. , Scott Leodis
Published: July 2016

This chapter contributes a conceptual framework for addressing the health of communities through the synergy of leisure, public health, and continuing education systems at a localized city level. The culture learning cities offers a broader setting and case for implementing solutions that increase the overall health of communities. Key built environments within learning cities, such as parks, can serve as nontraditional continuing education structures, where people can learn and share their differences and experiences that continually improve qualities of the individual, community, and society.
Framework of Indian Healthcare System and its Challenges
Authors: Mehta Prashant
Published: July 2016

India, one of the oldest civilizations and second most populous country is ethnically, linguistically, geographically, religious, and demographically diverse is poorly ranked due to complex public healthcare system, which suffers from insufficient funding, poor management. Poor health intertwined with poverty, affordability, accessibility, burden of infectious and non-communicable affecting lives of most Indians. Healthcare ecosystems are complex and still evolving, investments in service delivery system, infrastructure, and technology, are still being experimented and explored. India's booming population; increasing purchasing power; rising awareness of personal health and hygiene; and significant growth in infectious, chronic degenerative, and lifestyle diseases are driving the growing market. In this chapter we will explore accessible and affordable healthcare system, state of public healthcare, healthcare reforms, governance (Constitutional Provisions, Law, and Policy framework) in healthcare delivery, and Opportunity offered by market drivers.
Use of Soldered or Glued PCSB as Interconnection between PCB and Ceramic Package in Harsh Environment
Authors: Gakkestad Jakob , Opland Ottar , Dalsjø Per , Helland Susanne , Kristiansen Helge , Visser Taklo Maaike M. , Wright Daniel N.
Published: July 2016

Polymer Core Solder Balls (PCSB) have been used as interconnects between a 16 pin leadless chip carrier (LCC) ceramic package and a small FR4 board. A comparison was made between two different volumes of SnPb solder and an isotropic conductive adhesive (ICA) for the attachment of the PCSB to the board and to the package. Shear testing and electrical measurements were performed to characterize the interconnects as bonded and during thermal shock cycling (TSC) tests. No significant reductions of the measured fracture forces was observed for any of the sample groups. However, using a larger volume of solder or ICA resulted in less degradation of interconnect resistance during TSC, and the results for the solder were overall better than for ICA.
Reliability of Passive UHF RFID Copper Tags on Plywood Substrate in High Humidity Conditions
Authors: Sipilä Erja , Virkki Johanna , Sydänheimo Lauri , Ukkonen Leena
Published: July 2016

The growth of the wireless world, especially the increasing popularity of the Internet of Things, has created a need for cost-effective and environmentally friendly electronics. Great potential lies especially in versatile applications of passive UHF RFID components. However, the reliability of these components is a major issue to be addressed. This paper presents a preliminary reliability study of glue-coated and non-coated brush-painted copper tags on a plywood substrate in high humidity conditions. The passive UHF RFID components presented in this paper are fabricated using brush-painting and photonic sintering of cost-effective copper oxide ink directly on a plywood substrate. The performance of the glue-coated and non-coated tags is evaluated through wireless tag measurements before and after high humidity testing. The measurement results show that the copper tags on plywood substrate initially achieve peak read ranges of 7–8 meters and the applied coating does not affect to the read range. Moisture does not prevent the coated tags from working in a tolerable way, although the tag performance slightly temporarily decreases due to the moisture absorption. However, when the moisture exposure is long, the performance degradation comes irreversible. The absorbed moisture decreases the read range of the non-coated tags and the performance does not return back to normal after drying. Hence, the coating improves the reliability of the tags in a moist environment compared to the non-coated tags. Based on our results, the plywood material and the used manufacturing methods are very potential for low-cost, high-volume green electronics manufacturing.
A CG-Type Method for Inverse Quadratic Eigenvalue Problems in Model Updating of Structural Dynamics
Authors: Li Jiaofen , Hu Xiyan
Published: July 2016

In this paper we first present a CG-type method for inverse eigenvalue problem of constructing real and symmetric matricesM, DandKfor the quadratic pencilQ(λ) =λ2M+ λD+K, so thatQ(λ) has a prescribed subset of eigenvalues and eigenvectors. This method can determine the solvability of the inverse eigenvalue problem automatically. We then consider the least squares model for updating a quadratic pencilQ(λ). More precisely, we update the model coefficient matrices M, C and K so that (i) the updated model reproduces the measured data, (ii) the symmetry of the original model is preserved, and (iii) the difference between the analytical triplet (M, D, K) and the updated triplet (Mnew,Dnew,Knew) is minimized. In this paper a computationally efficient method is provided for such model updating and numerical examples are given to illustrate the effectiveness of the proposed method.
Modeling of Ice-Water Phase Change in Horizontal Annulus Using Modified Enthalpy Method
Authors: Tombarević Esad , Vušanović Igor
Published: July 2016

Phase change in ice-water systems in the geometry of horizontal cylindrical annulus with constant inner wall temperature and adiabatic outer wall is modeled with an enthalpy-based mixture model. Solidification and melting phenomena under different temperature conditions are analyzed through a sequence of numerical calculations. In the case of freezing of water, the importance of convection and conduction as well as the influence of cold pipe temperature on time for the complete solidification are examined. As for the case of melting of ice, the influence of the inner pipe wall temperature on the shape of the ice-water interface, the flow and temperature fields in the liquid, the heat transfer coefficients and the rate of melting are analyzed. The results of numerical calculations point to good qualitative agreement with the available experimental and other numerical results.
Finite Element θ-Schemes for the Acoustic Wave Equation
Authors: Karaa Samir
Published: July 2016

In this paper, we investigate the stability and convergence of a family of implicit finite difference schemes in time and Galerkin finite element methods in space for the numerical solution of the acoustic wave equation. The schemes cover the classical explicit second-order leapfrog scheme and the fourth-order accurate scheme in time obtained by the modified equation method. We derive general stability conditions for the family of implicit schemes covering some well-known CFL conditions. Optimal error estimates are obtained. For sufficiently smooth solutions, we demonstrate that the maximal error in the L2-norm error over a finite time interval converges optimally as O(hp+1 + ∆ts), where p denotes the polynomial degree, s=2 or 4, h the mesh size, and ∆t the time step.
A Maximum Entropy Method Based on Orthogonal Polynomials for Frobenius-Perron Operators
Authors: Ding Jiu , Rhee Noah H.
Published: July 2016

Let S: [0, 1]→[0, 1] be a chaotic map and let f* be a stationary density of the Frobenius-Perron operator PS: L1→L1 associated with S. We develop a numerical algorithm for approximating f*, using the maximum entropy approach to an under-determined moment problem and the Chebyshev polynomials for the stability consideration. Numerical experiments show considerable improvements to both the original maximum entropy method and the discrete maximum entropy method.
On Modifications of Continuous and Discrete Maximum Principles for Reaction-Diffusion Problems
Authors: Faragó István , Korotov Sergey , Szabó Tamás
Published: July 2016

In this work, we present and discuss some modifications, in the form
of two-sided estimation (and also for arbitrary source functions instead of usual sign-conditions), of continuous and discrete maximum principles for the reactiondiffusion problems solved by the finite element and finite difference methods.
A Brief Review of Elasticity and Viscoelasticity for Solids
Authors: Banks Harvey Thomas , Hu Shuhua , Kenz Zackary R.
Published: July 2016

There are a number of interesting applications where modeling elastic and/or viscoelastic materials is fundamental, including uses in civil engineering, the food industry, land mine detection and ultrasonic imaging. Here we provide an overview of the subject for both elastic and viscoelastic materials in order to understand the behavior of these materials. We begin with a brief introduction of some basic terminology and relationships in continuum mechanics, and a review of equations of motion in a continuum in both Lagrangian and Eulerian forms. To complete the set of equations, we then proceed to present and discuss a number of specific forms for the constitutive relationships between stress and strain proposed in the literature for both elastic and viscoelastic materials. In addition, we discuss some applications for these constitutive equations. Finally, we give a computational example describing the motion of soil experiencing dynamic loading by incorporating a specific form of constitutive equation into the equation of motion.
Hydrodynamic Regimes, Knudsen Layer, Numerical Schemes: Definition of Boundary Fluxes
Authors: Besse Christophe , Borghol Saja , Goudon Thierry , Lacroix-Violet Ingrid , Dudon Jean-Paul
Published: July 2016

We propose a numerical solution to incorporate in the simulation of a system of conservation laws boundary conditions that come from a microscopic modeling in the small mean free path regime. The typical example we discuss is the derivation of the Euler system from the BGK equation. The boundary condition relies on the analysis of boundary layers formation that accounts from the fact that the incoming kinetic flux might be far from the thermodynamic equilibrium.
Adaptive Finite Element Approximations for a Class of Nonlinear Eigenvalue Problems in Quantum Physics
Authors: Chen Huajie , Gong Xingao , He Lianhua , Zhou Aihui
Published: July 2016

In this paper, we study an adaptive finite element method for a class of nonlinear eigenvalue problems resulting from quantum physics that may have a nonconvex energy functional. We prove the convergence of adaptive finite element approximations and present several numerical examples of micro-structure of matter calculations that support our theory.
Algebraic Multigrid Preconditioning for Finite Element Solution of Inhomogeneous Elastic Inclusion Problems in Articular Cartilage
Authors: Hu Zhengzheng , Haider Mansoor A
Published: July 2016

In studying biomechanical deformation in articular cartilage, the presence of cells (chondrocytes) necessitates the consideration of inhomogeneous elasticity problems in which cells are idealized as soft inclusions within a stiff extracellular matrix. An analytical solution of a soft inclusion problem is derived and used to evaluate iterative numerical solutions of the associated linear algebraic system based on discretization via the finite element method, and use of an iterative conjugate gradient method with algebraic multigrid preconditioning (AMG-PCG). Accuracy and efficiency of the AMG-PCG algorithm is compared to two other conjugate gradient algorithms with diagonal preconditioning (DS-PCG) or a modified incomplete LU decomposition (Euclid-PCG) based on comparison to the analytical solution. While all three algorithms are shown to be accurate, the AMG-PCG algorithm is demonstrated to provide significant savings in CPU time as the number of nodal unknowns is increased. In contrast to the other two algorithms, the AMG-PCG algorithm also exhibits little sensitivity of CPU time and number of iterations to variations in material properties that are known to significantly affect model variables. Results demonstrate the benefits of algebraic multigrid preconditioners for the iterative solution of assembled linear systems based on finite element modeling of soft elastic inclusion problems and may be particularly advantageous for large scale problems with many nodal unknowns.
A Novel Perturbative Iteration Algorithm for Effective and Efficient Solution of Frequency-Dependent Eigenvalue Problems
Authors: Lin Rongming
Published: July 2016

Many engineering structures exhibit frequency dependent characteristics and analyses of these structures lead to frequency dependent eigenvalue problems. This paper presents a novel perturbative iteration (PI) algorithm which can be used to effectively and efficiently solve frequency dependent eigenvalue problems of general frequency dependent systems. Mathematical formulations of the proposed method are developed and based on these formulations, a computer algorithm is devised. Extensive numerical case examples are given to demonstrate the practicality of the proposed method. When all modes are included, the method is exact and when only a subset of modes are used, very accurate results are obtained.
Modifying and Reducing Numerical Dissipation in A Two-Dimensional Central-Upwind Scheme
Authors: Yu Chi-Jer , Liu Chii-Tung
Published: July 2016

This study presents a modification of the central-upwind Kurganov scheme for approximating the solution of the 2D Euler equation. The prototype, extended from a 1D model, reduces substantially less dissipation than expected. The problem arises from over-restriction of some slope limiters, which keep slopes between interfaces of cells to be Total-Variation-Diminishing. This study reports the defect and presents a re-derived optimal formula. Numerical experiments highlight the significance of this formula, especially in long-time, large-scale simulations.
Development and Comparative Studies of Three Non-free Parameter Lattice Boltzmann Models for Simulation of Compressible Flows
Authors: Yang L. M. , Shu C. , Wu J.
Published: July 2016

This paper at first shows the details of finite volume-based lattice Boltzmann method (FV-LBM) for simulation of compressible flows with shock waves. In the FV-LBM, the normal convective flux at the interface of a cell is evaluated by using one-dimensional compressible lattice Boltzmann model, while the tangential flux is calculated using the same way as used in the conventional Euler solvers. The paper then presents a platform to construct one-dimensional compressible lattice Boltzmann model for its use in FV-LBM. The platform is formed from the conservation forms of moments. Under the platform, both the equilibrium distribution functions and lattice velocities can be determined, and therefore, non-free parameter model can be developed. The paper particularly presents three typical non-free parameter models, D1Q3, D1Q4 and D1Q5. The performances of these three models for simulation of compressible flows are investigated by a brief analysis and their application to solve some one-dimensional and two-dimensional test problems. Numerical results showed that D1Q3 model costs the least computation time and D1Q4 and D1Q5 models have the wider application range of Mach number. From the results, it seems that D1Q4 model could be the best choice for the FV-LBM simulation of hypersonic flows.
Collocation Methods for A Class of Volterra Integral Functional Equations with Multiple Proportional Delays
Authors: Zhang Kai , Li Jie
Published: July 2016

In this paper, we apply the collocation methods to a class of Volterra integral functional equations with multiple proportional delays (VIFEMPDs). We shall present the existence, uniqueness and regularity properties of analytic solutions for this type of equations, and then analyze the convergence orders of the collocation solutions and give corresponding error estimates. The numerical results verify our theoretical analysis.
Numerical Simulation of a Multi-Frequency Resistivity Logging-While-Drilling Tool Using a Highly Accurate and Adaptive Higher-Order Finite Element Method
Authors: Ma Zhonghua , Liu Dejun , Li Hui , Gao Xinsheng
Published: July 2016

A novel, highly efficient and accurate adaptive higher-order finite element method (hp-FEM) is used to simulate a multi-frequency resistivity logging-while-drilling (LWD) tool response in a borehole environment. Presented in this study are the vector expression of Maxwell’s equations, three kinds of boundary conditions, stability weak formulation of Maxwell’s equations, and automatichp-adaptivity strategy. The newhp-FEM can select optimal refinement and calculation strategies based on the practical formation model and error estimation. Numerical experiments show that the newhp-FEM has an exponential convergence rate in terms of relative error in a user-prescribed quantity of interest against the degrees of freedom, which provides more accurate results than those obtained using the adaptiveh-FEM. The numerical results illustrate the high efficiency and accuracy of the method at a given LWD tool structure and parameters in different physical models, which further confirm the accuracy of the results using the Hermes library (http://hpfem.org/hermes) with a multi-frequency resistivity LWD tool response in a borehole environment.
Moving Finite Element Simulations for Reaction-Diffusion Systems
Authors: Hu Guanghui , Qiao Zhonghua , Tang Tao
Published: July 2016

This work is concerned with the numerical simulations for two reaction-diffusion systems, i.e., the Brusselator model and the Gray-Scott model. The numerical algorithm is based upon a moving finite element method which helps to resolve large solution gradients. High quality meshes are obtained for both the spot replication and the moving wave along boundaries by using proper monitor functions. Unlike [33], this work finds out the importance of the boundary grid redistribution which is particularly important for a class of problems for the Brusselator model. Several ways for verifying the quality of the numerical solutions are also proposed, which may be of important use for comparisons.
Shape Analysis and Solution to a Class of Nonlinear Wave Equation with Cubic Term
Authors: Li Xiang , Zhang Weiguo , Zhao Yan
Published: July 2016

In this paper, we analyze the relation between the shape of the bounded traveling wave solutions and dissipation coefficient of nonlinear wave equation with cubic term by the theory and method of planar dynamical systems. Two critical values which can characterize the scale of dissipation effect are obtained. If dissipation effect is not less than a certain critical value, the traveling wave solutions appear as kink profile; while if it is less than this critical value, they appear as damped oscillatory. All expressions of bounded traveling wave solutions are presented, including exact expressions of bell and kink profile solitary wave solutions, as well as approximate expressions of damped oscillatory solutions. For approximate damped oscillatory solution, using homogenization principle, we give its error estimate by establishing the integral equation which reflects the relations between the exact and approximate solutions. It can be seen that the error is an infinitesimal decreasing in the exponential form.
A High-Order NVD/TVD-Based Polynomial Upwind Scheme for the Modified Burgers’ Equations
Authors: Gao Wei , Liu Yang , Cao Bin , Li Hong
Published: July 2016

A bounded high order upwind scheme is presented for the modified Burgers’ equation by using the normalized-variable formulation in the finite volume framework. The characteristic line of the present scheme in the normalized-variable diagram is designed on the Hermite polynomial interpolation. In order to suppress unphysical oscillations, the present scheme respects both the TVD (total variational diminishing) constraint and CBC (convection boundedness criterion) condition. Numerical results demonstrate the present scheme possesses good robustness and high resolution for the modified Burgers’ equation.
An Acceleration Method for Stationary Iterative Solution to Linear System of Equations
Authors: Lin Qun , Peng Wujian
Published: July 2016

An acceleration scheme based on stationary iterative methods is presented for solving linear system of equations. Unlike Chebyshev semi-iterative method which requires accurate estimation of the bounds for iterative matrix eigenvalues, we use a wide range of Chebyshev-like polynomials for the accelerating process without estimating the bounds of the iterative matrix. A detailed error analysis is presented and convergence rates are obtained. Numerical experiments are carried out and comparisons with classical Jacobi and Chebyshev semi-iterative methods are provided.
Group Invariant Solutions of the Full Plastic Torsion of Rod with Arbitrary Shaped Cross Sections
Authors: Huang Kefu , Li Houguo
Published: July 2016

Based on the theory of Lie group analysis, the full plastic torsion of rod with arbitrary shaped cross sections that consists in the equilibrium equation and the non-linear Saint Venant-Mises yield criterion is studied. Full symmetry group admitted by the equilibrium equation and the yield criterion is a finitely generated Lie group with ten parameters. Several subgroups of the full symmetry group are used to generate invariants and group invariant solutions. Moreover, physical explanations of each group invariant solution are discussed by all appropriate transformations. The methodology and solution techniques used belong to the analytical realm.
Application of Improved (G′/G)–Expansion Method to Traveling Wave Solutions of Two Nonlinear Evolution Equations
Authors: Liu Xiaohua , Zhang Weiguo , Li Zhengming
Published: July 2016

In this work, the improved (G′/G)-expansion method is proposed for constructing more general exact solutions of nonlinear evolution equation with the aid of symbolic computation. In order to illustrate the validity of the method we choose the RLW equation and SRLW equation. As a result, many new and more general exact solutions have been obtained for the equations. We will compare our solutions with those gained by the other authors.
Steady States of Sheared Active Nematics
Authors: Cui Zhenlu , Zeng Xiaoming , Su Jianbing
Published: July 2016

A continuum hydrodynamic model has been used to characterize flowing active nematics. The behavior of such a system subjected to a weak steady shear is analyzed. We explore the director structures and flow behaviors of the system in flow-aligning and flow tumbling regimes. Combining asymptotic analysis and numerical simulations, we extend previous studies to give a complete characterization of the steady states for both contractile and extensile particles in flow-aligning and flow-tumbling regimes. Another key prediction of this work is the role of the system size on the steady states of an active nematic system: if the system size is small, the velocity and the director angle files for both flow-tumbling contractile and extensile systems are similar to those of passive nematics; if the system is big, the velocity and the director angle files for flow-aligning contractile systems and tumbling extensile systems are akin to sheared passive cholesterics while they are oscillatory for flow-aligning extensile and tumbling contractile systems.
New Error Estimates of Nonconforming Finite Element Methods for the Poisson Problem with Low Regularity Solution
Authors: Li Youai
Published: July 2016

In this paper, we revisit a priori error analysis of nonconforming finite element methods for the Poisson problem. Based on some techniques developed in the context of the a posteriori error analysis, under two reasonable assumptions on the nonconforming finite element spaces, we prove that, up to some oscillation terms, the consistency error can be bounded by the approximation error. We check these two assumptions for the most used lower order nonconforming finite element methods. Compared with the classical error analysis of the nonconforming finite element method, the a priori analysis herein only needs the H1 regularity of the exact solution.
A Second-Order Three-Level Difference Scheme for a Magneto-Thermo-Elasticity Model
Authors: Cao Hai-Yan , Sun Zhi-Zhong , Zhao Xuan
Published: July 2016

This article deals with the numerical solution to the magneto-thermo-elasticity model, which is a system of the third order partial differential equations. By introducing a new function, the model is transformed into a system of the second order generalized hyperbolic equations. A priori estimate with the conservation for the problem is established. Then a three-level finite difference scheme is derived. The unique solvability, unconditional stability and second-order convergence inL∞-norm of the difference scheme are proved. One numerical example is presented to demonstrate the accuracy and efficiency of the proposed method.
Modified Ghost Fluid Method as Applied to Fluid-Plate Interaction
Authors: Xu Liang , Liu Tiegang
Published: July 2016

The modified ghost fluid method (MGFM) provides a robust and efficient interface treatment for various multi-medium flow simulations and some particular fluid-structure interaction (FSI) simulations. However, this methodology for one specific class of FSI problems, where the structure is plate, remains to be developed. This work is devoted to extending the MGFM to treat compressible fluid coupled with a thin elastic plate. In order to take into account the influence of simultaneous interaction at the interface, a fluid-plate coupling system is constructed at each time step and solved approximately to predict the interfacial states. Then, ghost fluid states and plate load can be defined by utilizing the obtained interfacial states. A type of acceleration strategy in the coupling process is presented to pursue higher efficiency. Several one-dimensional examples are used to highlight the utility of thismethod over looselycoupled method and validate the acceleration techniques. Especially, this method is applied to compute the underwater explosions (UNDEX) near thin elastic plates. Evolution of strong shock impacting on the thin elastic plate and dynamic response of the plate are investigated. Numerical results disclose that this methodology for treatment of the fluid-plate coupling indeed works conveniently and accurately for different structural flexibilities and is capable of efficiently simulating the processes of UNDEX with the employment of the acceleration strategy.