IYTE GCRIS Database (Izmir Institute of Technology)
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Vis-Assist: Computer Vision and Haptic Feedback-Based Wearable Assistive Device for Visually Impaired
No full textVisual impairment affects millions of people worldwide, posing significant challenges in their daily lives and personal safety. While assistive technologies, both wearable and non-wearable, can help mitigate these challenges, wearable devices offer the advantage of hands-free operation. In this context, we present Vis-Assist, a novel wearable visual assistive device capable of detecting and classifying objects, measuring their distances, and providing real-time haptic feedback through a vibration motor array, all using an integrated low-cost computational unit without the need for external servers. Our study distinguishes itself by utilizing haptic feedback to convey object information, allowing visually impaired individuals to discern between 19 different object classes following a brief training period. Haptic feedback offers an alternative to audio that doesn't block hearing and can be used alongside it, serving as a complementary solution. The performance of the developed wearable device was evaluated through two types of experiments with four participants. The results demonstrate that users can identify the location of objects and thereby prevent collisions with obstacles. The experiments conducted demonstrate that users, on average, can locate a predefined object, such as a chair, within a 40 m2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}\end{document} vacant space in under 94 seconds. Furthermore, users exhibit proficiency in finding objects while navigating around obstacles in the same environment, achieving this task in less than 121 seconds on average. The system developed here has high potential to help the self-navigation of visually impaired people and make their daily lives easier. To facilitate further research in this field, the complete source code for this study has been made publicly available on GitHub
Dynamic and Stochastic Optimization of Algae Cultivation Process
No full textThis study offers a realistic representation of system dynamics which accounts for light intensity, biomass, substrate, and nitrogen concentration, by employing stochastic programming techniques to account for spatial and temporal variations for algae growth. The optimization task focuses on lipid productivity and selectivity, which are crucial factors in the context of algal biofuel production. Different scenarios from likely and unlikely cases of model parameters were evaluated. Optimal initial conditions for key variables such as nitrogen, substrate, light, biomass, lipid, and surface light intensity are calculated, considering the uncertainty of the parameters as well as other governing equations. The results show that a remarkable 11.18% increase in lipid productivity compared to a reference scenario. Furthermore, in the stochastic case, our results highlight that uncertainty has a disproportionately large effect on biomass in comparison to lipid concentration, providing valuable insights into the behavior of the system under varying conditions. This provides a comprehensive exploration of the parameter uncertainty on lipid productivity and algal growth
Food Question in Planning: Perspectives From Two Turkish Metropolis
No full textThis study examines the integration of urban food systems into planning practices within Türkiye's two major metropolises: İzmir and Ankara. Addressing the challenges posed by climate change, urbanization, and economic crises, the research advocates for a transformative approach to urban food systems through socio-ecological and circularity frameworks. It identifies systemic vulnerabilities in the current agri-food systems, including environmental degradation, social inequalities, and inefficiencies in food production, distribution, and consumption. Through qualitative methodologies—semi-structured interviews, ethnographic observations, and content analysis of strategic planning documents—the study explores local agri-food strategies, emphasizing the critical need for holistic urban food planning. While İzmir demonstrates significant progress with its basin-based agricultural strategies, Ankara’s fragmented initiatives reveal a pressing need for cohesive urban food strategies. Both cities struggle with integrating rural-urban food linkages and systemic planning for storage, logistics, and equitable food access. The findings underscore the potential of localized, participatory governance in enhancing food sovereignty and resilience. However, the research highlights that piecemeal strategies remain insufficient to address the multifaceted challenges of food insecurity and environmental sustainability, advocating for comprehensive, equitable, and regenerative urban food systems as critical components of sustainable urban food planning and development. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024
Nanoarchitectonics Approach To Graphite/Starch-supported Bioelectrode for Enhanced Supercapacitor Performance
No full textThere has been an increasing interest in finding suitable materials for supercapacitor applications in response to the growing need for energy, to use alternative energy sources to fossil fuels in addition to energy storage. In this regard, bio-based carbon-loaded materials can be a promising option for high-performance supercapacitors because of their abundance, diversity, and reproducibility with waste management strategies. In this study, a new graphite-loaded bioelectrode is synthesized for supercapacitor application. The electrochemical performance of the synthesized electrode is tested at room temperature using the cyclic voltammetry method, and the capacity and energy density of the electrodes are evaluated. The electrochemical performance of 1 g of graphiteloaded bioelectrode was 3.5 mA/cm2, while the specific capacitance value was 355.6 F/g at a current density of 0.5 A/g. Furthermore, the bioelectrode provided significant cyclic stability with 93.5% in specific capacitance value after 5000 charge/discharge cycles at the current density of 0.5 A/g. Consequently, the synthesized bioelectrode can be a promising option for energy storage as a sustainable electrode due to its superior conductivity, stability, and low cost
Ultrafast High-Temperature Sintering of Yttria-Stabilized Zirconia in Reactive Nsub>2/Sub> Atmosphere
No full textSo far, ultrafast high-temperature sintering (UHS) has always been carried out in an inert environment. In the present work, we investigated UHS of 3YSZ in nitrogen and argon atmosphere showing that "the atmosphere matters". Highly densified samples can be obtained in both environments but densification and grain growth are significantly retarded in N-2. Moreover, the phase evolution is strongly atmosphere-dependent with the samples treated in Ar remaining tetragonal and those treated under N-2 progressively reducing their tetragonality, eventually converting into cubic zirconia and rock salt oxynitride. The results can be explained by the incorporation of nitrogen within the ZrO2 lattice. Electrochemical impedance spectroscopy demonstrates that while the ionic bulk conductivity are marginally influenced by the sintering atmosphere, the grain boundaries' capacitive behavior strongly changes. After UHS under 30 A, excellent ionic conductors were obtained without substantial grain boundary-blocking effects
Estimation of Settlement-Induced Damage in Masonry Buildings From Displacement Measurements
No full textIn current engineering practice, building damage due to nearby ground excavation activities is typically quantified by processing displacement measurements. Building displacements at discrete points are used to determine deflection measures (such as angular distortion) which are then employed to estimate building strains using elastic beam models; damage is subsequently categorised according to the limiting tensile strain criteria. The reliability of this procedure relies on the extent to which the equivalent beam models employed in the analysis provide a realistic representation of the building behaviour. However, few published investigations are available on this issue. The current paper provides an appraisal of displacement-based building damage estimation techniques by employing digital image correlation displacement data collected from a recent experimental campaign on the settlement response of three half-scale masonry buildings. The results demonstrate that the treatment of buildings with equivalent beam models does not capture building deformation kinematics, potentially leading to inaccurate estimations of damage severity and location. An alternative strain interpretation procedure, inspired by an equivalent frame idealisation of a building fa ; ccedil;ade with openings, is proposed. This procedure, which uses a limited number of displacement measurements, offers a robust interpretation of strains. Its effectiveness in estimating damage is assessed through experimental data. It is demonstrated that the current limiting tensile strain criteria need to be modified to provide a reliable estimation of crack widths when using the equivalent frame idealisation
Recent Advances in Hydrogel-Based 3D Disease Modeling and Drug Screening Platforms
No full textThree-dimensional (3D) disease modeling and drug screening systems have become important in tissue engineering, drug screening, and development. The newly developed systems support cell and extracellular matrix (ECM) interactions, which are necessary for the formation of the tissue or an accurate model of a disease. Hydrogels are favorable biomaterials due to their properties: biocompatibility, high swelling capacity, tunable viscosity, mechanical properties, and their ability to biomimic the structure and function of ECM. They have been used to model various diseases such as tumors, cancer diseases, neurodegenerative diseases, cardiac diseases, and cardiovascular diseases. Additive manufacturing approaches, such as 3D printing/bioprinting, stereolithography (SLA), selective laser sintering (SLS), and fused deposition modeling (FDM), enable the design of scaffolds with high precision; thus, increasing the accuracy of the disease models. In addition, the aforementioned methodologies improve the design of the hydrogel-based scaffolds, which resemble the complicated structure and intricate microenvironment of tissues or tumors, further advancing the development of therapeutic agents and strategies. Thus, 3D hydrogel-based disease models fabricated through additive manufacturing approaches provide an enhanced 3D microenvironment that empowers personalized medicine toward targeted therapeutics, in accordance with 3D drug screening platforms. © 2025. The Author(s), under exclusive license to Springer Nature Switzerland AG
Staging Nişantaşı: Cultural Conflicts and Ideological Representations of Urban Space in Turkish Tv Culture
No full textThis paper examines how urban spaces become sites of ideological contestation through their representation in popular media, focusing specifically on Ni ; scedil;anta ; scedilimath;, a historically significant neighborhood in Istanbul that embodies the class tensions within T ; uuml;rkiye's modernization narrative. Drawing on cultural geography as a theoretical framework, the study analyzes how this distinctive urban space functions as both physical setting and symbolic element in post-2000 Turkish television dramas. Since the expansion of private broadcasting, these TV series have emerged as powerful agents in shaping public consciousness about space, class, and identity. Through semiotic analysis of selected programs, this research reveals how Ni ; scedil;anta ; scedilimath;'s portrayal constructs and reinforces social class distinctions in contemporary Turkish society. The findings demonstrate that urban geography serves as a reflective surface for cultural and social conflict, with television representations amplifying Ni ; scedil;anta ; scedilimath;'s multi-layered spatial identity formed through historical processes, societal dynamics, and personal narratives. By connecting these representations to broader patterns of class differentiation in T ; uuml;rkiye, this study contributes to our understanding of how media portrayals of urban spaces simultaneously reflect and reinforce class distinction through collective social imaginaries
Vibration Analysis and Optimal Design of Multiscale Hybrid Flax Fiber/ Graphene Nanoplatelets Reinforced Laminates Using Modified Differential Evolution Algorithm
No full textOne of the relatively recent developments in composites is using different material combinations and nano-scale reinforcements such as Graphene Nanoplatelets (GPLs) to develop hybrid fiber composites. A further development is the use of natural flax fiber in composites in response to a growing demand over the past few decades for affordable, lightweight, and environmentally-friendly materials. In order to meet this growing demand, in the present study composites based on graphene nanoplatelets and flax fibers are investigated considering their weight, cost, and natural frequency implications. Furthermore, the Modified Differential Evolution (MDE) algorithm is implemented for the optimum design problems involving the stacking sequences and weight fractions of GPLs in each layer. For the optimal design problems, natural frequency is defined as the objective function with the design variables specified as the orientations of flax fibers and the weight contents of GPLs in each layer. The effective material properties are computed based on Halpin-Tsai and the rule of mixture formulations. Navier solution approach is implemented to solve the eigenvalue problems with the stiffness matrix based on the Firstorder Shear Deformation Theory (FSDT). Optimal designs based on flax fibers, optimal GPL contents, and stacking sequences lead to efficient and environmentally-friendly composite plates. Optimum multiscale hybrid nanocomposite designs include high natural frequency, light weight, and cost-effectiveness compared to conventional carbon and glass fibers reinforced equivalents
A Novel Ml-Dem Algorithm for Predicting Particle Motion in Rotary Drums
No full textThe discrete element method (DEM) is a widely used approach for studying the behavior of particles in industrial equipment, including rotary drums. Although DEM is highly accurate and efficient, it suffers from the computational cost in simulations. The primary objective of this research is to reduce the computational costs of DEM by introducing a novel machine learning (ML) approach based on a deep neural network for predicting particle behavior in rotary drums. The proposed approach utilizes a continuous convolution operator in a neural network. To evaluate its effectiveness, the results of the proposed ML-DEM approach were compared quantitatively and qualitatively with the experimental data and the conventional DEM results. It was shown that in addition to its high accuracy, the proposed approach reduces the computational costs by approximately 35 % and 65 % compared to the conventional DEM simulations on GPU and CPU (with 8 processors), respectively. Furthermore, to ensure the comprehensive and independent validation of the proposed algorithm, the study investigated the effects of various parameters such as drum rotational speed and fill ratio on lateral entropy-based mixing, circulation time, and velocity profile in the active layer. The results were then compared with those obtained using the conventional DEM and found to be in good agreement. This new algorithm can serve as a starting point for reducing computational costs in simulating particle motion in granular systems