Makine Mühendisliği Bölümü Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.11779/1944
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Conference Object The Minimum Variance Distortionless Response Beamformer for Damage Identification Using Modal Curvatures(Association of American Publishers, 2023) Eroğlu, Uğurcan; Pau, A.This study presents a damage identification procedure in beams based on the use of beamforming algorithms, which are mostly utilized in inverse problems of source identification and image reconstruction. We choose the modal curvatures as observed quantities and compare the performance of the Bartlett beamformer, minimum variance distortionless response (MVDR) processor, and of a conventional objective function based on the modal curvatures. By means of a set of experiments, we show that the MVDR processor can overcome some of the difficulties encountered with other estimators, especially in cases of slight damage, or damage located between two sensors. © 2023, Association of American Publishers. All rights reserved.Conference Object Perturbations for Vibration of Nano-Beams of Local/Nonlocal Mixture(Association of American Publishers, 2023) Ruta, Giuseppe; Eroğlu, UğurcanHere we extend the perturbation approach, previously presented in the literature for Eringen’s two-phase local/nonlocal mixture model, to free vibration of purely flexible beams. In particular, we expand the eigenvalues and the eigenvectors into power series of the fraction coefficient of the non-local material response up to 2nd order. We show that the family of 0th order bending couples satisfy the natural and essential boundary conditions of the 1st order; hence, the 1st order solution can conveniently be constructed using the eigenspace of the 0th order with no necessity of additional conditions. We obtain the condition of solvability that provides the incremental eigenvalue in closed form. We further demonstrate that the 1st order increment of the eigenvalue is always negative, providing the well-known softening effect of long-range interactions among the material points of a continuum modelled with Eringen’s theory. We examine a simply supported beam as a benchmark problem and present the incremental eigenvalues in closed form. © 2023, Association of American Publishers. All rights reserved.Conference Object Citation - Scopus: 6System-On Based Driver Drowsiness Detection and Warning System(IEEE, 2022) Yazici, Berkay; Ayhan, Tuba; Özdemir, ArdaThe aim of this project is to detect the drowsiness level of the driver in the vehicle, to warn the driver and to prevent possible accidents. Percentage Eye Closure (PERCLOS) and Convolutional Neural Network (CNN) are used to detect drowsiness. The system is implemented on Xilinx PYNQ-Z2 development board. The system is tested under real world conditions in real time. A high accuracy rate of 92% and a fast working system with 0.8 s is achieved. A speaker is activated to warn the driver when drowsiness is detected. Moreover, the drowsiness information is sent to the cloud by using a Wi-Fi module.Conference Object Assessment of the Models for Predicting the Responses of Spherical Objects in Viscoelastic Mediums and at Viscoelastic Interfaces(IOP Publishing Ltd, 2021) Körük, HasanSpherical objects, such as bubbles and spheres, embedded in mediums and atviscoelastic interfaces are encountered in many applications, including the determination ofmaterial properties. This paper assesses the models for predicting the responses of sphericalobjects in viscoelastic mediums and at viscoelastic interfaces used in various applications. Themodels are presented very compactly, and evaluations are performed based on the analyses ofthe models for the spherical objects in viscoelastic mediums and at viscoelastic interfaces. First,the models for predicting the static displacements of spherical objects are presented andassessed. After that, the models for predicting the dynamic responses of spherical objects arepresented and their dynamic behaviours are compared. Then, the models for the deformation ofthe medium around spherical objects and stress distribution are presented and evaluated. Themodels and evaluations presented in this study can be exploited in various applications,including biomedical applications.Conference Object Development of a Model for Predicting Dynamic Response of a Sphere at Viscoelastic Interface: a Dynamic Hertz Model(IOP Publishing Ltd, 2021) Körük, HasanA model for predicting the dynamic response of a sphere at viscoelastic interface is presented. The model is based on Hertz contact model and the model for a sphere in a medium.In addition to the elastic properties of medium and the size of sphere, the model considers thedensity of sphere, the density and viscosity of medium, and damping of oscillations of spheredue to radiation of shear waves. The model can predict not only the effects of the mechanicalproperties of medium, the physical properties of sphere, and the amplitude of excitation forceon sphere displacement, but also the effects of these parameters on shift of resonancefrequency. The proposed model can be used to identify the elastic and damping properties ofmaterials, and to understand the dynamic responses of spherical objects at viscoelasticinterfaces in practical applications.Conference Object Study of Tuned Mass Damper for Attenuating Skyscraper Oscillations Through Project-Based Learning(Filodiritto Publisher, 2019) Şengül, Özden; Dorantes-Gonzalez, Dante JorgeThe intention of the project was to introduce a complex real-life engineering problem in an easy manner to sophomore students, namely, the topic of a tuned mass damper (TMD). Even though TMD is a multiple-degree-of-freedom vibration problem seen only in advanced university courses, the phenomenon of earthquake effects on buildings is easy to understand. In order to ease the complexity, the multi-degree-of-freedom mathematical problem was converted into a single degree of freedom, such as the behavior of a vertical single-mass cantilever beam. Through a do-it-yourself project to be done in home conditions, students are introduced to the topic of mechanical vibrations via seismic action on tall buildings. Two sections of the "Engineering Mechanics: Dynamics" course, with an overall number of 58 students, participated in the project. The project develops critical thinking and inquiry skills by designing and constructing the physical prototype of a building-like structure and its corresponding tuned mass damper; conducting an experiment under certain restrictions to test the stabilizing effect of the damper after an initial displacement; learning a proper software application to graph and measure underdamped oscillations; calculating corresponding vibration parameters; as well as analyzing and discussing experimental results. Students approach the problem of mass-damper tuning by means of trial and error, an on-purpose strategy to add fun and gambling to the process, to enthusiastically compete for the best performance in terms of efficiency of attenuation. Data were collected from direct observation, surveys, reports and presentations. The results showed that students positively and enthusiastically responded at all project stages and with a better understanding of the phenomenon and engagement in comparison with previous students of the same course without project. The impact of the project on students’ engagement and implications for engineering education are discussed.Conference Object Improved Business Model Representation of Innovation Concepts(World Conference on Technology, Innovation and Entrepreneurship, 2015) Dorantes-Gonzalez, Dante Jorge; Küçükaydın, Hande; Özlem, Şirin; Bulgan, Gökçe; Aydın, Utkun; Son Turan, Semen; Karamollaoğlu, Nazlı; Teixeira, Frederico FialhoExcept for academics and consultants, the concept and purpose of innovation (not to mention related concepts such as “Open Innovation", "Free-Intellectual Property Innovation," or "Open Source Innovation") is usually unclear for most entrepreneurs and other practitioners. It often times happens that newly coined terminology becomes misleading or may even include a certain degree of sensationalism, hence turning into a matter of debate for specialists in the realm of technology management. Such has been the case for the term “Open Innovation”, since the word “open” is mainly related to crowd sourced innovation, but not for the openness on intellectual property rights. Since innovation is about the commercialization of original ideas, so we propose a simple and visual business model setting to resolve these concepts. To this regard, the “Business Model Canvas” has been used in business and entrepreneurship to sketch and frame the key points behind the development of a startup. This model was suggested by Alexander Osterwalder (2008) in his work on Business Model Ontology, as a strategic analysis template for developing startups or documenting existing businesses. It describes the firm’s value proposition, partners, resources, activities, customer relationships, distribution channels, customers, revenue streams and cost structure. However, when it comes to innovative startups, this template does not explicitly include such significant innovation components as intellectual property, its alignment to strategies, and intellectual property flow. The present paper proposes the use of an improved version of the Business Model Canvas to originally represent different models of innovation like Open Innovation, thus providing a clear, visual and quick representation of their meaning, and consequently, contribute to a better understanding of different concepts of innovation.Conference Object A Novel Business Model Frame for Innovative Startups - (may 12-14, 2017)(World Conference on Technology, Innovation and Entrepreneurship, 2017) Dorantes-Gonzalez, Dante JorgeThe business model canvas has been used in business and entrepreneurship to sketch and frame the key points behind the development of a startup, and it was meant to strategically analyze and develop startups or documenting existing businesses. The business model canvas describes the firm’s value proposition, partners, resources, activities, customer relationships, distribution channels, customers, revenue streams and cost structure. However, when it comes to innovative startups, this template does not explicitly include innovation measures, no problem/opportunity formulation, or even such a basic component of a business model, as the profit formula. The present paper proposes a novel business model frame to visually and concisely sketch, besides accurately state traditional business concepts, key innovation concepts that any startup should integrate to be a game-changer in a competitive market. This new model is based on a combination of key principles of the theory of inventive problem solving (TRIZ) applied to business and management, such as multi-screen analysis of value-conflict mapping, trends of ideality of business system evolution positioning, among others; but also intellectual property, disruptive strategies, and open innovation, as well as startup metrics to describe the business differentiation and attractiveness to potential investors, incubators and accelerators.Conference Object Laser-Generated Surface Acoustic Wave-Based Study and Detection of Surface Cracks(Int. Sc. & Tech. Conf. Beam technologies & Laser Applications, 2015) Chen, Kun; Fu, Xing; Li, Tingting; Dorantes-Gonzalez, Dante Jorge; Li, Yanning; Wu, SenMonitoring cracks to check the integrity of engineering materials by Non- Destructive Testing (NDT) in industry is significant in industry. And within the NDT techniques, Laser-Generated Surface Acoustic Wave technique (LSAW) has shown to be a promising technique. To further develop non-contact and accurate testing strengths of this method, models for analyzing the generation, propagation and tracking of surface acoustic waves (SAW’s) changes in S45C steel samples with distributed cracks are developed by using Finite Element Method (FEM). Time and frequency domain analyses are used to process the acoustic wave signals after the interaction with cracks. The simulation results and preliminary analyses reveal the good potential LSAW’s have to monitor cracks. First results in developing an experimental setup for crack detection are also provided.Conference Object A Business Model Frame for Innovative Startups - (july 11-15, 2017)(Global Business & Technology Association, 2017) Dorantes-Gonzalez, Dante JorgeCurrent business model frames such as the Business Model Canvas and the Lean Canvas do not address aspects of open innovation, problem statement, innovative problem solving, business metrics and disruptive strategies; therefore, a novel business model frame is introduced to cover these aspects. This new model is based on a combination of key principles of the theory of inventive problem solving applied to business and management, such as multi-screen analysis of value-conflict mapping, trends of ideality of business system evolution positioning, among others; but also, intellectual property, disruptive strategies, and open innovation, as well as startup metrics to describe the business differentiation and attractiveness to potential investors, incubators and accelerators. The entrepreneur designing his/her own startup should be able to justify if not all, most of the items to be able to demonstrate the idea strengths. And regarding both building blocks “Product Formulation and Inventive Problem Solving” and “Disruption Strategy”, certain training should be necessary.