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Dr. Atila Ertas
Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409, USA

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0 galling
0 3D Printing Technology
0 Test method development
0 Transdisciplinary complex system design

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Journal article
Published: 10 May 2021 in Designs
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The continued displacement of refugees from their homes and homelands (now greater than 50 million people worldwide) places increased focus and attention on evolving the designs of temporary housing that is available to be provided to the refugee population, especially in rural areas where housing does not already exist and must be constructed in very little time. Complex engineering problems involving social issues, such as this case study, benefit from the use of Integrated Transdisciplinary (TD) Tools (ITDT) to effectively and efficiently address the design questions related to them. The integrated use of TD Tools such as Kano Analysis, KJ Diagrams, Critical to Quality (CTQ), House of Quality (HOQ)/Quality Function Design (QFD), Theory of Inventive Problem Solving (TRIZ), Axiomatic Design (AD), Interpretive Structural Modeling (ISM), and Design Structure Matrix (DSM) through an end-to-end unique design process leads to innovation and elimination of design conflicts for especially complicated design problems. The objective of this study is to examine the design of temporary refugee housing using integrated TD tools mentioned above. This research concludes that the use of the ITDT approach provides an innovative, decoupled design.

ACS Style

Daniel Moran; Atila Ertas; Utku Gulbulak. A Unique Transdisciplinary Engineering-Based Integrated Approach for the Design of Temporary Refugee Housing Using Kano, HOQ/QFD, TRIZ, AD, ISM and DSM Tools. Designs 2021, 5, 31 .

AMA Style

Daniel Moran, Atila Ertas, Utku Gulbulak. A Unique Transdisciplinary Engineering-Based Integrated Approach for the Design of Temporary Refugee Housing Using Kano, HOQ/QFD, TRIZ, AD, ISM and DSM Tools. Designs. 2021; 5 (2):31.

Chicago/Turabian Style

Daniel Moran; Atila Ertas; Utku Gulbulak. 2021. "A Unique Transdisciplinary Engineering-Based Integrated Approach for the Design of Temporary Refugee Housing Using Kano, HOQ/QFD, TRIZ, AD, ISM and DSM Tools." Designs 5, no. 2: 31.

Journal article
Published: 07 January 2021 in Education Sciences
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Transdisciplinary research (TR) is a growing field in a myriad of subject domains ranging from sustainability to education. The idea is to solve complex problems through the collaborative participation of academic actors, community stakeholders, governments, and other leaders to jointly define the problem and find solutions. To accomplish such complex projects, one of the main tools is an efficient technology platform. The need for an efficient technology platform, in turn, leads to a need for an evaluation tool to determine which is the most suitable for a given transdisciplinary research situation, however, a literature review confirms that research on such evaluation tools is scarce. The goal of this paper is to improve the evaluation of technology platforms for individual TR projects, based on the characteristics of that specific TR. The research question is “Can TR characteristics be used to construct an evaluation tool for technology platforms?” The specific aims used to answer the question were: the following: (1) to define the characteristics (core activities and skills) of TR and (2) to construct a tool for evaluating technology platforms for use in TR. Methodology: For the first specific aim, a literature meta-analysis was used; the second specific aim was addressed following a newly developed methodology, including elements of the technology acceptance model and elements of a standard technology evaluation process. Results: A chart for defining the core activities and skills in TR was developed, and a tool was constructed for evaluating technology platforms that could be used in TR.

ACS Style

Pratap Chillakanti; Stephen Ekwaro-Osire; Atila Ertas. Evaluation of Technology Platforms for Use in Transdisciplinary Research. Education Sciences 2021, 11, 23 .

AMA Style

Pratap Chillakanti, Stephen Ekwaro-Osire, Atila Ertas. Evaluation of Technology Platforms for Use in Transdisciplinary Research. Education Sciences. 2021; 11 (1):23.

Chicago/Turabian Style

Pratap Chillakanti; Stephen Ekwaro-Osire; Atila Ertas. 2021. "Evaluation of Technology Platforms for Use in Transdisciplinary Research." Education Sciences 11, no. 1: 23.

Journal article
Published: 03 September 2020 in Computers
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The aerospace and defense industry is facing an end-of-life production issue with legacy embedded uniprocessor systems. Most, if not all, embedded processor manufacturers have already moved towards system-on-a-chip multicore architectures. Current scheduling arrangements do not consider schedules related to safety and security. The methods are also inefficient because they arbitrarily assign larger-than-necessary windows of execution. This research creates a hierarchical scheduling framework as a model for real-time multicore systems to integrate the scheduling for safe and secure systems. This provides a more efficient approach which automates the migration of embedded systems’ real-time software tasks to multicore architectures. A novel genetic algorithm with a unique objective function and encoding scheme was created and compared to classical bin-packing algorithms. The simulation results show the genetic algorithm had 1.8–2.5 times less error (a 56–71% difference), outperforming its counterparts in uniformity in utilization. This research provides an efficient, automated method for commercial, private and defense industries to use a genetic algorithm to create a feasible two-level hierarchical schedule for real-time embedded multicore systems that address safety and security constraints.

ACS Style

Brandon Woolley; Susan Mengel; Atila Ertas. An Evolutionary Approach for the Hierarchical Scheduling of Safety- and Security-Critical Multicore Architectures. Computers 2020, 9, 71 .

AMA Style

Brandon Woolley, Susan Mengel, Atila Ertas. An Evolutionary Approach for the Hierarchical Scheduling of Safety- and Security-Critical Multicore Architectures. Computers. 2020; 9 (3):71.

Chicago/Turabian Style

Brandon Woolley; Susan Mengel; Atila Ertas. 2020. "An Evolutionary Approach for the Hierarchical Scheduling of Safety- and Security-Critical Multicore Architectures." Computers 9, no. 3: 71.

Journal article
Published: 23 July 2020 in Applied Sciences
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The first part of this paper outlined the Statistical Agent-based Model of Development and Evaluation (SAbMDE) and demonstrated the model’s ability to estimate development cycle resource utilization. This second part of the paper explores the model’s ability to compute development cycle information content and process risk. Risk managers focus mostly on outcome risk, i.e., the likelihood that a running system will behave in an undesirable manner. SAbMDE assumes that a subset of outcome risks are not inherent and immutable but are, instead, the result of defects and vulnerabilities introduced during the system’s development process. The likelihood of defect and vulnerability introduction is a process risk. SAbMDE further assumes that measuring process risk is a prerequisite for minimizing defects and vulnerabilities and, therefore, outcome risk. The model implements the measurement with Shannon’s information–probability relationship similar to its use in Axiomatic Design Theory (ADT). This paper details the SAbMDE’s information and risk calculations and demonstrates those calculations with examples. The process risk calculation is consistent with and offers a mechanism for the ADT Information Axiom.

ACS Style

Samuel Denard; Atila Ertas; Susan Mengel; Stephen Ekwaro-Osire. Development Cycle Modeling: Process Risk. Applied Sciences 2020, 10, 5082 .

AMA Style

Samuel Denard, Atila Ertas, Susan Mengel, Stephen Ekwaro-Osire. Development Cycle Modeling: Process Risk. Applied Sciences. 2020; 10 (15):5082.

Chicago/Turabian Style

Samuel Denard; Atila Ertas; Susan Mengel; Stephen Ekwaro-Osire. 2020. "Development Cycle Modeling: Process Risk." Applied Sciences 10, no. 15: 5082.

Journal article
Published: 21 July 2020 in Applied Sciences
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This paper presents results produced by a domain-independent system development model that enables objective and quantitative calculation of certain development cycle characteristics. The presentation recounts the model’s motivation and includes an outline of the model’s structure. The outline shows that the model is constructive. As such, it provides an explanatory mechanism for the results that it produces, not just a representation of qualitative observations or measured data. The model is a Statistical Agent-based Model of Development and Evaluation (SAbMDE); and it appears to be novel with respect to previous design theory and methodology work. This paper focuses on one development cycle characteristic: resource utilization. The model’s resource estimation capability is compared to Boehm’s long-used software development estimation techniques. His Cone of Uncertainty (COU) captures project estimation accuracy empirically at project start but intuitively over a project’s duration. SAbMDE calculates estimation accuracy at start up and over project duration; and SAbMDE duplicates the COU’s empirical values. Additionally, SAbMDE produces results very similar to the Constructive Cost Model (COCOMO) effort estimation for a wide range of input values.

ACS Style

Samuel Denard; Atila Ertas; Susan Mengel; Stephen Ekwaro-Osire. Development Cycle Modeling: Resource Estimation. Applied Sciences 2020, 10, 5013 .

AMA Style

Samuel Denard, Atila Ertas, Susan Mengel, Stephen Ekwaro-Osire. Development Cycle Modeling: Resource Estimation. Applied Sciences. 2020; 10 (14):5013.

Chicago/Turabian Style

Samuel Denard; Atila Ertas; Susan Mengel; Stephen Ekwaro-Osire. 2020. "Development Cycle Modeling: Resource Estimation." Applied Sciences 10, no. 14: 5013.

Journal article
Published: 29 February 2020 in Transdisciplinary Journal of Engineering & Science
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This paper defines a process of predictive approach to evaluate the maintainability of a Commercial Off-the-Shelf (COTS)-based system(CBS) by analyzing the complexity of the deployment of the system. The approach integrates architectural dependencies and the system’s concept of operations to derive a network-based representation of the software system. A greater understanding of the deployment complexity is gained by using a Design Structure Matrix (DSM) to determine the number of architectural dependencies on a COTS product, or in-degree, for each COTS product in the system. The arithmetic mean of the in-degree for all nodes in the system is then compared with the perceived effort to maintain the system. The resultant measure – the in-degree mean – is useful in evaluating the maintainability of the operational system while the system is being designed and throughout its lifetime. Architects can use the approach to assist in COTS product selection and to make product trades to optimize the maintainability of the system. Integrators can use the approach to optimize product deployment and to determine the upgrade strategy for deployment. Finally, maintenance engineers can use the approach to estimate the effort required to maintain the system and to identify areas in which extensive product expertise is required. Because the approach requires only basic information about the system, it can be applied early in the design process and used until the system is decommissioned.

ACS Style

Michael Smith; William Lawson; Atila Ertas; James Surles. Process of Measuring the Maintainability of Commercial Off-the-Shelf (COTS) Based Systems: A Complexity Approach. Transdisciplinary Journal of Engineering & Science 2020, 11, 1 .

AMA Style

Michael Smith, William Lawson, Atila Ertas, James Surles. Process of Measuring the Maintainability of Commercial Off-the-Shelf (COTS) Based Systems: A Complexity Approach. Transdisciplinary Journal of Engineering & Science. 2020; 11 ():1.

Chicago/Turabian Style

Michael Smith; William Lawson; Atila Ertas; James Surles. 2020. "Process of Measuring the Maintainability of Commercial Off-the-Shelf (COTS) Based Systems: A Complexity Approach." Transdisciplinary Journal of Engineering & Science 11, no. : 1.

Journal article
Published: 05 February 2020 in Energies
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The development of adsorptive natural gas storage tanks for vehicles requires the synthesis of many technologies. The design for an effective Adsorbed Natural Gas (ANG) tank requires that the tank be filled isothermally within a five-minute charge time. The heat generated within the activated carbon is on the order of 150 MJ/m3 of storage volume. The tank can be effectively buffered using Phase Change Material (PCM) to absorb the heat. The effective design of these tanks requires knowledge of the thermal properties of activated carbon with adsorbed methane. This paper discusses experimental measurements of the thermal conductivity of activated carbon with adsorbed methane. It was found that within the tank the thermal conductivity remains almost constant within the temperature and pressure ranges that ANG tanks will operate.

ACS Style

Atila Ertas; Christopher T. R. Boyce; Utku Gulbulak. Experimental Measurement of Bulk Thermal Conductivity of Activated Carbon with Adsorbed Natural Gas for ANG Energy Storage Tank Design Application. Energies 2020, 13, 682 .

AMA Style

Atila Ertas, Christopher T. R. Boyce, Utku Gulbulak. Experimental Measurement of Bulk Thermal Conductivity of Activated Carbon with Adsorbed Natural Gas for ANG Energy Storage Tank Design Application. Energies. 2020; 13 (3):682.

Chicago/Turabian Style

Atila Ertas; Christopher T. R. Boyce; Utku Gulbulak. 2020. "Experimental Measurement of Bulk Thermal Conductivity of Activated Carbon with Adsorbed Natural Gas for ANG Energy Storage Tank Design Application." Energies 13, no. 3: 682.

Journal article
Published: 13 September 2019 in Bioengineering
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Almost ten percent of the American population have heart diseases. Since the number of available heart donors is not promising, left ventricular assist devices are implemented as bridge therapies. Development of the assist devices benefits from both in-vivo animal and in-vitro mock circulation studies. Representation of the heart is a crucial part of the mock circulation setups. Recently, a beating left ventricular simulator with latex rubber and helically oriented McKibben actuators has been proposed. The simulator was able to mimic heart wall motion, however, flow rate was reported to be limited to 2 liters per minute. This study offers a finite element driven design domain identification to identify the combination of wall thickness, number of actuators, and the orientation angle that results in better deformation. A nonlinear finite element model of the simulator was developed and validated. Design domain was constructed with 150 finite element models, each with varying wall thickness and number of actuators with varying orientation angles. Results showed that the combination of 4 mm wall thickness and 8 actuators with 90 degrees orientation performed best in the design domain.

ACS Style

Utku Gulbulak; Atila Ertas. Finite Element Driven Design Domain Identification of a Beating Left Ventricular Simulator. Bioengineering 2019, 6, 83 .

AMA Style

Utku Gulbulak, Atila Ertas. Finite Element Driven Design Domain Identification of a Beating Left Ventricular Simulator. Bioengineering. 2019; 6 (3):83.

Chicago/Turabian Style

Utku Gulbulak; Atila Ertas. 2019. "Finite Element Driven Design Domain Identification of a Beating Left Ventricular Simulator." Bioengineering 6, no. 3: 83.

Journal article
Published: 09 April 2019 in Metals
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The first part of this paper explored the identification of various methodological challenges which have to be addressed when designing complex multi-system integration associated with titanium metalworking and manufacture, while in this second part of the paper, we explore the evolution of System of Systems (SoS) design and development of complex multi-system integration. Theory of Inventive Problem Solving (TRIZ) is employed to address identified system incongruity. The utilization of the SoS design approach coupled with the TRIZ innovation technique proved effective at addressing the system constraints for the titanium manufacturing supply chain. The utilization of the two-part process prescribed by the SoS design approach proved effective at addressing requirements and broadly stated industry needs. Through this unique system, design net-shaped structural beam from common aerospace grade titanium (Ti-6Al-4V) was successfully manufactured.

ACS Style

Adam Stroud; Atila Ertas. Net Shape Extrusion of Titanium Bars through Coupled two Part Preform Manufacturing Process: System of Systems Approach—Part II. Metals 2019, 9, 423 .

AMA Style

Adam Stroud, Atila Ertas. Net Shape Extrusion of Titanium Bars through Coupled two Part Preform Manufacturing Process: System of Systems Approach—Part II. Metals. 2019; 9 (4):423.

Chicago/Turabian Style

Adam Stroud; Atila Ertas. 2019. "Net Shape Extrusion of Titanium Bars through Coupled two Part Preform Manufacturing Process: System of Systems Approach—Part II." Metals 9, no. 4: 423.

Journal article
Published: 09 April 2019 in Metals
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Titanium has an excellent combination of properties that make it an attractive material for use in aerospace applications. The one area in which titanium is not aligned with customer needs is affordability. Components made from titanium are many times more expensive than those manufactured from other alloys. The supply chain of an extruded product is no exception. A breakthrough in extrusion cost reduction would enable wider adoption of titanium in many structural member applications. In an effort to accomplish any breakthrough in titanium component costs, the entire supply chain for manufacturing should be evaluated simultaneously. Due to the complex interaction of the many facets of the systems in a manufacturing supply chain, it is inferred that the supply chain in its entirety must be the focus of the design activity in order to be successful. Design improvements on a single facet of manufacture may have little to no effect on the manufacture of the component. If the improvement has a detrimental impact on another system in the supply chain, overall performance may be lowered. The use of a system of systems’ (SoS) design approach was used due to its capability to address complex multi-system integration problems associated with titanium metalworking and manufacture.

ACS Style

Adam Stroud; Atila Ertas. Complex Multi-System Integration Problems Associated with Titanium Metalworking and Manufacture: System of Systems Aproach—Part I. Metals 2019, 9, 424 .

AMA Style

Adam Stroud, Atila Ertas. Complex Multi-System Integration Problems Associated with Titanium Metalworking and Manufacture: System of Systems Aproach—Part I. Metals. 2019; 9 (4):424.

Chicago/Turabian Style

Adam Stroud; Atila Ertas. 2019. "Complex Multi-System Integration Problems Associated with Titanium Metalworking and Manufacture: System of Systems Aproach—Part I." Metals 9, no. 4: 424.

Journal article
Published: 01 April 2018 in Journal of Manufacturing Processes
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ACS Style

A.W. Stroud; Atila Ertas. Development of a rolling finishing system to deliver net shape components from titanium structural extruded shapes. Journal of Manufacturing Processes 2018, 32, 187 -198.

AMA Style

A.W. Stroud, Atila Ertas. Development of a rolling finishing system to deliver net shape components from titanium structural extruded shapes. Journal of Manufacturing Processes. 2018; 32 ():187-198.

Chicago/Turabian Style

A.W. Stroud; Atila Ertas. 2018. "Development of a rolling finishing system to deliver net shape components from titanium structural extruded shapes." Journal of Manufacturing Processes 32, no. : 187-198.

Book chapter
Published: 24 May 2017 in Transdisciplinary Higher Education
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Transdisciplinary education offers an opportunity to enhance complex problem-solving skills for engineers (among other disciplines), increase efficacy for diverse students, and increase possibilities for deep learning experiences. In order to test the efficacy of Transdisciplinary (TD) content pedagogy, we undertook a quasi-experimental case study design research project where we compared the levels of engagement, trust, collaboration, and problem-solving skills developed in an undergraduate mechanical engineering course and compared those results with a ‘control’ mechanical engineering course that was on the same subject matter and taught by the same teacher. Findings suggest that the TD course does increase collaboration, problem-solving, and engagement. Our results also show that TD content pedagogy allows students to engage in rich learning experiences that create moments where they see the world differently, where they are ‘pulled up short’; and this approach may give students important advantages in the classroom and the workforce.

ACS Style

H. Greenhalgh-Spencer; K. Frias; A. Ertas. Transdisciplinary Content Pedagogy in Undergraduate Engineering Education: Being Pulled Up Short. Transdisciplinary Higher Education 2017, 73 -89.

AMA Style

H. Greenhalgh-Spencer, K. Frias, A. Ertas. Transdisciplinary Content Pedagogy in Undergraduate Engineering Education: Being Pulled Up Short. Transdisciplinary Higher Education. 2017; ():73-89.

Chicago/Turabian Style

H. Greenhalgh-Spencer; K. Frias; A. Ertas. 2017. "Transdisciplinary Content Pedagogy in Undergraduate Engineering Education: Being Pulled Up Short." Transdisciplinary Higher Education , no. : 73-89.

Research article
Published: 30 August 2016 in Shock and Vibration
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Structures which are commonly used in our infrastructures are becoming lighter with progress in material science. These structures due to their light weight and low stiffness have shown potential problem of wind-induced vibrations, a direct outcome of which is fatigue failure. In particular, if the structure is long and flexible, failure by fatigue will be inevitable if not designed properly. The main objective of this paper is to perform theoretical analysis for a novel free pendulum device as a passive vibration absorber. In this paper, the beam-tip mass-free pendulum structure is treated as a flexible multibody dynamic system and the ANCF formulation is used to demonstrate the coupled nonlinear dynamics of a large deflection of a beam with an appendage consisting of a mass-ball system. It is also aimed at showing the complete energy transfer between two modes occurring when the beam frequency is twice the ball frequency, which is known as autoparametric vibration absorption. Results are discussed and compared with findings of MSC ADAMS. This novel free pendulum device is practical and feasible passive vibration absorber in the mitigation of large amplitude wind-induced vibrations in traffic signal structures.1. IntroductionMany mechanical systems can be modeled as a beam with a lumped mass, such as a wing of an airplane with a mounted engine, a robot arm carrying a welding tool, or a traffic light. Understanding the dynamics of those systems having flexible and slender beams is of great importance in vibration analyses to prevent catastrophic failures of the structures. Therefore, there is an extensive amount of experimental and numerical work on the responses of beams in the nonlinear dynamics and vibration field.There is widespread interest in pendulum modeling and the use of the pendulum as a vibration absorber. This interest ranges from the dynamics of Josephson’s Junction in solid state physics [1] to the rolling motion of ships [2, 3] and the rocking motion of buildings and structures under earthquakes [4].Autoparametric vibration absorber is a device designed to absorb the energy from the primary mass (main mass) at conditions of combined internal and external resonance. Autoparametric resonance is a special case of parametric vibration and is said to exist if the conditions at the internal resonance and external resonance are met simultaneously due to external force [5–7]. Autoparametric vibration absorber has received considerable attention since mid-1980s and researchers published many interesting papers [8–19]. There are many practical examples of designing vibration absorber published using the concept of autoparametric resonance [20–26].The first studies in multibody systems were on the dynamics of the rigid bodies which were related to gyrodynamics, the mechanism theory, and biomechanics. A good review of this topic is given by Schiehlen [27]. One of the first formalisms is given by Hooker and Margulies [28] in which they analyzed the satellites interconnected with spherical joints. Another formulation was published in 1967 by Roberson and Wittenburg [29]. Wittenburg [30] wrote the first textbook on multibody dynamics in which he explained rigid body kinematics and dynamics as well as general multibody systems. In 1988, Nikravesh [31] provided information about the computer-aided analysis of multibody systems in his textbook. Haug [32] provided basic methods of the computer-aided kinematics and dynamics for spatial and planar systems. Many more authors provided textbooks in the field of kinematic and dynamic simulations of multibody systems such as Roberson and Schwertassek [33], Huston [34], and García de Jalón and Bayo [35].Until now, we discussed papers and textbooks that were related to the multibody systems consisting of rigid bodies. However, in many applications, bodies undergo large deformations, which necessitate the modeling of the flexible bodies. Flexible multibody systems have attracted many researchers and several flexible multibody formulations have been established such as the floating frame of reference method, incremental finite element corotational method, and the large rotation vector method. Agrawal and Shabana [36] proposed the component mode synthesis method in which each elastic component is identified by three sets of modes: rigid body, reference modes, and normal modes. Rigid body modes are used to describe the rigid body translation and large rotations of a body reference, reference modes are used to define a unique displacement field, and the normal modes are used to define the deformation relative to the body reference. An alternative formulation was proposed by Yoo and Haug [37] in which a lumped mass finite element structural analysis formulation is used to generate deformation modes. In the floating reference frame formulation, a mixed set of absolute and local deformation coordinates are used to define the configuration of the deformable body [38–40]. This method became the most widely used approach due to its straightforward nature. However, the mass matrix, centrifugal, and Coriolis forces appear to be highly nonlinear. The incremental finite element approach uses rotation angles as nodal variables, which lead to linearized kinematic equations. Therefore, models obtained by using incremental finite elements cannot describe the exact rigid body displacements [41]. In order to solve this problem in the incremental finite element approach, a different approach called the large rotation vector formulation has been proposed. In this method, finite rotations are employed instead of infinitesimal rotations, which results in an exact modeling of the rigid body displacements [42].Most of the methods explained above suffer from highly nonlinear terms inside the mass matrix, centrifugal, and Coriolis forces. Therefore, a new approach called the absolute nodal coordinate formulation (ANCF) was proposed for the solution of large deformation problems [40, 43–50]. In this formulation, instead of the angle of rotations, absolute slopes are used as nodal variables.In this paper, the beam-tip mass-ball structure is treated as a flexible multibody dynamic system and the ANCF formulation is used to demonstrate the coupled nonlinear dynamics of a large deflection of a beam with an appendage consisting of a mass-free pendulum system. This novel free pendulum device is practical and feasible passive vibration absorber in the mitigation of large amplitude wind-induced vibrations in traffic signal structures.2. Formulation of Equations of Motions for Flexible Multibody Dynamics2.1. Displacement FieldIn this paper, a planar beam element is used to model flexible beam under investigation. Referring to Figure 1, the global position vector of an arbitrary point on the element is defined in terms of the nodal coordinates and the element shape function as [44]where is the global shape function and is the vector of element nodal coordinates defined asThe elements of the vector of nodal coordinates are defined as [44]where is the beam element length and is the axial coordinate that defines the position of an arbitrary point on the element in the undeformed state. , , , and are the absolute displacement coordinates and , , , and are the global slopes of the nodes.Figure 1: Planar beam element.The element shape function can be defined as [43]where2.2. Mass MatrixKinetic energy of the finite element can be written asSubstituting (1) into (6) yieldswhere is the element volume, is the mass density of the beam element material, and is the mass matrix of the element. Using (7), the mass matrix of the element can be calculated as2.3. Generalized Elastic ForcesIn order to develop the equations of motion of the beam element, generalized elastic forces, , corresponding to the beam element have to be defined. If the strain energy of the element is , then the vector of elastic forces is defined asIn this paper, continuum mechanics approach is used to derive the strain energy of the element in the absolute nodal coordinate formulation. This approach uses arc length to define the element deformation instead of using the local coordinate system. The strain energy of the element can be written aswhere is the strain energy due to the longitudinal deformation and is the strain energy due to the bending.The longitudinal strain, , and the bending curvature, , can be defined as [51] Using (1), (9), (10), and (11), one can find the vector of elastic forces as where stiffness matrices and are defined as [51]More detailed derivation for the elastic forces is well explained in [51].2.4. Generalized Gravity ForcesLet be the distributed gravity force applied on an arbitrary point on the element. Then, the virtual work done due to this external force can be defined aswhere is the virtual change in the position vector of the point of application of the force. Using (1), one can write the virtual work term aswhere is the vector of generalized forces associated with the element nodal coordinates.Using (15), virtual work due to the distributed gravity force of the beam element for the planar case can be written as Therefore, using (16), the vector of generalized distributed gravity forces can be written as2.5. Generalized Constraint ForcesLet be the set of generalized coordinates of the flexible body, where is the number of coordinates. If is the number of the constraints, where , then the vector of constraint equations can be written in the form ofand the Jacobian of the constraint equations can be defined asUsing the vector of Lagrange Multipliers, , one can write generalized constraint forces, , as [40]where is given by (19) and is defined as2.6. Equations of MotionUsing the principles of virtual work in dynamics and the expression of the kinetic and strain energies given in (6) and (10), the system equations of motion in augmented form can be written as [40]where is the constant symmetric mass matrix, is the vector of

ACS Style

Emrah Gumus; Atila Ertas. Analysis of Free Pendulum Vibration Absorber Using Flexible Multi-Body Dynamics. Shock and Vibration 2016, 2016, 1 -19.

AMA Style

Emrah Gumus, Atila Ertas. Analysis of Free Pendulum Vibration Absorber Using Flexible Multi-Body Dynamics. Shock and Vibration. 2016; 2016 ():1-19.

Chicago/Turabian Style

Emrah Gumus; Atila Ertas. 2016. "Analysis of Free Pendulum Vibration Absorber Using Flexible Multi-Body Dynamics." Shock and Vibration 2016, no. : 1-19.

Journal article
Published: 14 May 2016 in Journal of Systems Science and Systems Engineering
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ACS Style

A. Ertas; M. W. Smith; D. Tate; W. D. Lawson; T. B. Baturalp. Complexity of system maintainability analysis based on the interpretive structural modeling methodology: Transdisciplinary approach. Journal of Systems Science and Systems Engineering 2016, 25, 254 -268.

AMA Style

A. Ertas, M. W. Smith, D. Tate, W. D. Lawson, T. B. Baturalp. Complexity of system maintainability analysis based on the interpretive structural modeling methodology: Transdisciplinary approach. Journal of Systems Science and Systems Engineering. 2016; 25 (2):254-268.

Chicago/Turabian Style

A. Ertas; M. W. Smith; D. Tate; W. D. Lawson; T. B. Baturalp. 2016. "Complexity of system maintainability analysis based on the interpretive structural modeling methodology: Transdisciplinary approach." Journal of Systems Science and Systems Engineering 25, no. 2: 254-268.

Conference paper
Published: 01 April 2016 in 2016 Annual IEEE Systems Conference (SysCon)
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This paper shows how the McCabe cyclomatic complexity measure can be applied to enterprise architectures using standard enterprise architecture framework tools.

ACS Style

Bob Stroud; Atila Ertas. Enterprise cyclomatic complexity. 2016 Annual IEEE Systems Conference (SysCon) 2016, 1 -7.

AMA Style

Bob Stroud, Atila Ertas. Enterprise cyclomatic complexity. 2016 Annual IEEE Systems Conference (SysCon). 2016; ():1-7.

Chicago/Turabian Style

Bob Stroud; Atila Ertas. 2016. "Enterprise cyclomatic complexity." 2016 Annual IEEE Systems Conference (SysCon) , no. : 1-7.

Book chapter
Published: 01 January 2016 in Emerging Trends in Applications and Infrastructures for Computational Biology, Bioinformatics, and Systems Biology
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A novel, fully automated systemic mock human circulation loop (MCL) design is proposed, prototyped, and introduced with a wide literature review of MCL and left ventricular (LV) form and function. Drawbacks and strengths of current MCLs and their pumping systems are investigated and an inference has been made for requirements of a novel MCL design. It has been found that proposed MCL design should not only be capable of replicating a wide range of cardiac operating scenarios, but also the pumping system should better represent LV for simulating various cardiovascular diseases, particularly muscular dysfunctions. Also, the proposed MCL design should be fully automated and control essential MCL parameters such as compliance and resistance. Medical papers showed that LV has principal functionalities such as elastance, torsional, and twisting motion of ventricular wall, which play an important role in motion and contraction of LV. These features are implemented on a proposed pneumatic muscle-actuated heart simulator that only contains a LV chamber.

ACS Style

T.B. Baturalp; A. Ertas. State-of-the-Art Mock Human Blood Circulation Loop. Emerging Trends in Applications and Infrastructures for Computational Biology, Bioinformatics, and Systems Biology 2016, 357 -369.

AMA Style

T.B. Baturalp, A. Ertas. State-of-the-Art Mock Human Blood Circulation Loop. Emerging Trends in Applications and Infrastructures for Computational Biology, Bioinformatics, and Systems Biology. 2016; ():357-369.

Chicago/Turabian Style

T.B. Baturalp; A. Ertas. 2016. "State-of-the-Art Mock Human Blood Circulation Loop." Emerging Trends in Applications and Infrastructures for Computational Biology, Bioinformatics, and Systems Biology , no. : 357-369.

Journal article
Published: 09 June 2015 in International Journal on Artificial Intelligence Tools
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An innovative process that assists users in non-quantitative problem solving is presented. The process, called Ramic, employs the idea of psychological projection in an innovative way to help users focus, express and think through problems. Its applicability ranges from assisting with simple non-analytic decision-making to developing and assessing strategies. In the virtual realm, harnessing the power of psychological projection for problem solving has been attempted in the form of a process called Sand Tray. Attempts at virtualization have garnered little traction potentially due to encumbrance of the interface. Ramic, in contrast, is innately set up for digital use through a relatively simple interface. A key question this paper explores is how to quantitatively measure the value of Ramic in relation to the well-established process of Sand Tray. Even though these processes operate on qualitative problems, a preference analysis tool called conjoint analysis is used to build an experiment and derive specific user utilities for each process. To perform the study, both processes required testing in the physical domain. A 32-person study is presented and indicates the Ramic projective process to have a 23% higher user utility than Sand Tray in the area of problem solving. As such, it presents an opportunity to explore a new way in which individuals can approach non-analytical problem solving and how computers can assist them in the task.

ACS Style

Vijay Ramamoorthy; Atila Ertas; Derrick Tate. Assessing a New Projective Problem Solving Tool Using Conjoint Analysis. International Journal on Artificial Intelligence Tools 2015, 24, 1 .

AMA Style

Vijay Ramamoorthy, Atila Ertas, Derrick Tate. Assessing a New Projective Problem Solving Tool Using Conjoint Analysis. International Journal on Artificial Intelligence Tools. 2015; 24 (3):1.

Chicago/Turabian Style

Vijay Ramamoorthy; Atila Ertas; Derrick Tate. 2015. "Assessing a New Projective Problem Solving Tool Using Conjoint Analysis." International Journal on Artificial Intelligence Tools 24, no. 3: 1.

Conference paper
Published: 01 April 2015 in 2015 Annual IEEE Systems Conference (SysCon) Proceedings
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This paper exposes Enterprise Architecture (EA) taxonomy work in process in support of research in the use of EA Frameworks (EAFs) to address complexity in enterprise design.

ACS Style

Bob Stroud; Atila Ertas. A taxonomy for enterprise architecture framework. 2015 Annual IEEE Systems Conference (SysCon) Proceedings 2015, 828 -831.

AMA Style

Bob Stroud, Atila Ertas. A taxonomy for enterprise architecture framework. 2015 Annual IEEE Systems Conference (SysCon) Proceedings. 2015; ():828-831.

Chicago/Turabian Style

Bob Stroud; Atila Ertas. 2015. "A taxonomy for enterprise architecture framework." 2015 Annual IEEE Systems Conference (SysCon) Proceedings , no. : 828-831.

Journal article
Published: 08 October 2014 in Journal of Mechanical Design
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Inherent in biologically inspired design (BID) is the selection of one or more analogs from which one or more strategies are extracted and transferred into the engineering domain. The selection of an analog is a fundamental step in biomimetic process, but locating relevant biological analogies can be challenging. Often, designers may fixate on an analogy or choose an established analogy without rigorous examination of alternatives. This practice is problematic—as basing a new design on an invalid assumption can lead to suboptimal results. This paper makes contribution to evaluation of analogy utility. The contribution is made by combining stochastic multicriteria acceptability analysis (SMAA) with a set of criteria, derived from BID, to assist multidisciplinary decision makers (DMs) in evaluating candidate design analogs. The resulting framework, which we call the biotransferability framework, is being developed to assist multidisciplinary teams to choose, rank, or sort candidate design analogs by assessing biology-to-engineering transfer risk.

ACS Style

M. Lindsey Williams; Atila Ertas; Derrick Tate. Using Stochastic Multicriteria Acceptability Analysis in Biologically Inspired Design as a Multidisciplinary Tool to Assess Biology-to-Engineering Transfer Risk for Candidate Analogs. Journal of Mechanical Design 2014, 136, 111107 .

AMA Style

M. Lindsey Williams, Atila Ertas, Derrick Tate. Using Stochastic Multicriteria Acceptability Analysis in Biologically Inspired Design as a Multidisciplinary Tool to Assess Biology-to-Engineering Transfer Risk for Candidate Analogs. Journal of Mechanical Design. 2014; 136 (11):111107.

Chicago/Turabian Style

M. Lindsey Williams; Atila Ertas; Derrick Tate. 2014. "Using Stochastic Multicriteria Acceptability Analysis in Biologically Inspired Design as a Multidisciplinary Tool to Assess Biology-to-Engineering Transfer Risk for Candidate Analogs." Journal of Mechanical Design 136, no. 11: 111107.

Conference paper
Published: 28 February 2012 in Conference Proceedings of the Society for Experimental Mechanics Series
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Using image processing and analysis, the dynamic behavior of the beam-free-pendulum system under low and high sinusoidal excitation was investigated. The system responses were investigated experimentally in the neighborhood of primary resonance condition. The results exhibited autoparametric interaction between the beam and the free pendulum when the primary resonance condition was satisfied. Experiments were conducted for two different pendulum weights under two different shaker forcing amplitudes, and the results were compared. Experimental data were obtained by sweeping between the frequencies that contain the resonance condition under investigation. The results of experiments for different beam-tip mass and pendulum mass ratios indicate that more powerful absorption action can be achieved when the smaller mass ratios are used.

ACS Style

Richard Landis; Atila Ertas; Emrah Gumus; Faruk Güngör. Free-Pendulum Vibration Absorber Experiment Using Digital Image Processing. Conference Proceedings of the Society for Experimental Mechanics Series 2012, 167 -180.

AMA Style

Richard Landis, Atila Ertas, Emrah Gumus, Faruk Güngör. Free-Pendulum Vibration Absorber Experiment Using Digital Image Processing. Conference Proceedings of the Society for Experimental Mechanics Series. 2012; ():167-180.

Chicago/Turabian Style

Richard Landis; Atila Ertas; Emrah Gumus; Faruk Güngör. 2012. "Free-Pendulum Vibration Absorber Experiment Using Digital Image Processing." Conference Proceedings of the Society for Experimental Mechanics Series , no. : 167-180.