Atılım Academic Archive (Atılım University)
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Randomised Comparison Between Navigation and Non-Navigation Camera Control Performance in a Surgical Simulation Task Using a Haptic Device Interface
No full textIntroduction:Navigation skills for controlling the camera in the surgical field are critical for many minimally invasive surgery (MIS) procedures. Currently, endoscopes lack integrated navigation aids, making camera control a challenging task. This experimental study aims to investigate the effect of navigation guidance on the performance of beginners.Patients and Methods:A custom computer-based simulation environment was developed for this study, featuring two conditions - one with navigation guidance and one without - focussed on a camera-cleaning task. Participants (64 beginners) were randomly assigned to one of these groups and used two haptic devices to simulate the endoscope and surgical tools.Results:Participants in the guided condition performed significantly better than those in the unguided condition. Notably, female participants completed the task in significantly less time under the guided condition compared to the unguided one.Conclusion:These findings suggest that incorporating navigation aids into endoscope interfaces could improve user performance, especially for beginners. Medical device manufacturers should consider adding navigation features to enhance usability. In addition, simulation-based instructional systems should integrate navigation aids to better support surgical training.TUBITAK [112K287]This study is conducted for improving the scenario designs of the educational materials which are developed for endo-neurosurgery education project (ECE: TUBITAK 1001, Project No: 112K287) purposes. The authors would like to thank the support of the TUEB & Idot;TAK 1001 programme for realising this research. The researchers would also like to thank the ECE project team and the Hacettepe University Medical School for their valuable support throughout the research
Regular AdS3 Black Holes From a Regularized Gauss-Bonnet Coupling
No full textWe obtain a three-dimensional bi-vector-tensor theory of the generalized Proca class by regularizing the Gauss-Bonnet invariant within the Weyl geometry. We show that the theory admits a regular AdS3 black hole solution with primary hairs. Introducing a deformation in the theory, a different regular AdS3 black hole solution is obtained. Charged generalizations of these solutions are given by coupling to Born-Infeld electrodynamics
Comparison of Voice Call Based and Multimodal Telerehabilitation After Total Knee Arthroplasty: A Randomized Controlled Trial
No full textBackground Telerehabilitation has emerged as a promising approach in postoperative care following total knee arthroplasty(TKA);nevertheless,the relative effectiveness of different telerehabilitation modules is still under discussion, leaving room for alternative and multimodal program approaches. Objectives This study aimed to compare the effectiveness of a multimodal telerehabilitation(MTR) and voice call based telerehabilitation(VTR) in patients undergoing TKA. Methods A two-arm randomized controlled trial was conducted with 24 patients (68.42 +/- 9.28y) in the MTR group and 21(71.19 +/- 7.26y) in the VTR group. The MTR group received weekly digital booklets containing asynchronous exercise videos, one voice call, one video call,and text messages,for a total of three contacts per week. The VTR group received weekly printed booklets and voice calls three times a week(on alternate days) over the 8-week intervention period. Outcomes were assessed face to face at discharge, and at the 4th and 8th postoperative weeks. Measures included Visual Analog Scale(VAS), active and passive range of motion(ROM), Knee Osteoarthritis Outcome Score-Physical Function(KOOS-PS), Five Repetition Sit to Stand Test(5xSST), Brief Fear of Movement(BFoM) Scale, isometric Quadriceps muscle strength, Forgotten Joint Score-12(FJS-12),Exercise Adherence Rating Scale(EARS). The primary outcome was active knee flexion ROM. Statistical significance was set at p < .05; effect sizes (r, W) were reported for the Mann - Whitney U and Wilcoxon tests. Results After 8 weeks, a statistically significant difference in pain during activity was observed between the MTR and VTR groups (p < .001, r = 0.62). Both groups showed significant gains in active and passive knee flexion ROM, 5xSST, and KOOS-PS scores (all p < .001), while the MTR group also improved in rest pain, knee extension, and BFoM (all p < .001). At week 8, statistically significant differences were observed between the MTR and VTR groups across all outcome measures (all p < .001). Conclusion Both telerehabilitation approaches were effective in improving pain, ROM, and functional outcomes after TKA.Although this study did not compare outcomes with conventional in-person rehabilitation, MTR showed greater overall improvements than VTR. Nevertheless, VTR remains a reasonable alternative when MTR cannot be implemented
Robust Divergence-Based Tests of Hypotheses for Simple Step-Stress Accelerated Life-Testing Under Gamma Lifetime Distributions
No full textMany modern devices are highly reliable, with long lifetimes before their failure. Conducting reliability tests under actual use conditions may require therefore impractically long experimental times to gather sufficient data for developing accurate inference. To address this, Accelerated Life Tests (ALTs) are often used in industrial experiments to induce product degradation and eventual failure more quickly by increasing certain environmental stress factors. Data collected under such increased stress conditions are analyzed, and results are then extrapolated to normal operating conditions. These tests typically involve a small number of devices and so pose significant challenges, such as interval-censoring. As a result, the outcomes are particularly sensitive to outliers in the data. Additionally, a comprehensive analysis requires more than just point estimation; inferential methods such as confidence intervals and hypothesis testing are essential to fully assess the reliability behaviour of the product. This paper presents robust statistical methods based on minimum divergence estimators for analyzing ALT data of highly reliable devices under step-stress conditions and Gamma lifetime distributions. Robust test statistics generalizing the Rao test and divergence-based tests for testing linear null hypothesis are then developed. These hypotheses include in particular tests for the significance of the identified stress factors and for the validity of the assumption of exponential lifetimes. © 202
The Existence of Positive Solutions to the Fractional Q-Differential Equations with Integral Boundary Conditions
No full textIn this research, we investigate the existence of positive solutions to the fractional q-differential equations under new specified boundary conditions. We employ the alpha-theta-contraction fixed point theorem to analyze our results. Additionally, several examples are provided to illustrate the main results
Semiautomated Delay Analysis Method Selection for Construction Projects: A Rule-Based Approach
No full textGiven the availability of various delay analysis methods, each yielding different results, the proper selection of an appropriate methodology is of paramount importance. Despite the necessity for automation to resolve delay conflicts, the current literature lacks an automated approach to assist contractors and project owners in reaching a consensus on selecting the most suitable delay analysis method without requiring a third party. Hence, to bridge the gap between theoretical research and practical application in achieving an automated delay analysis method, a novel rule-based expert system has been proposed. A structured, multiphase methodology that includes a review of existing methods, identification of key facts, determination of facts and expert rules, development of a forward chaining inference engine, and validation stages is used. Five real-world case examples and the decisions of experts for 15 hypothetical case examples are used for validation. The case examples demonstrate that the system can successfully automate the selection of the most appropriate delay analysis method and support a transparent, systematic approach to managing delays in construction projects. Furthermore, the system can foster consensus among project stakeholders during the selection of a delay analysis method and has the potential to contribute to the resolution of delay disputes
An Approach for Regime-Switching Stochastic Control Problems With Memory and Terminal Conditions
Full text linkSavku, Emel/0000-0001-8731-2928In this research article, we focus on a stochastic optimal control problem with two types of terminal constraints. These specific conditions provide real-valued and stochastic Lagrange multipliers. Our model evolves according to a Markov regime-switching jump diffusion model with memory. In this context, the memory is represented by a Stochastic Differential Delay Equation. We present two theorems for each constraint within the general formulation of stochastic optimal control theory in a Lagrangian environment. We approach to this task from a theoretical perspective and provide mild technical assumptions, which make our theorems applicable for a broad class of stochastic control problems as well as for a wide range of disciplines such as engineering, biology, operations research, medicine, computer science and economics. In this work, we apply Stochastic Maximum Principle to demonstrate an optimal dividend policy corresponding to a time-delayed wealth process of a company. Moreover, we determine the real-valued Lagrange multiplier of this control problem explicitly
Potential Localization Strategies and Strategic Instruments in Nuclear Power Generation
No full textDeploying the right strategies is of paramount importance and plays a key role in technology transfer to achieve localization. Today, around 30 countries are considering or embarking on nuclear power programs. What are the potential strategies for nuclear power technology localization? This study attempts to identify localization strategies in nuclear technology and also to unfold tested approaches, business models, strategic legal and technical instruments. The methodology of the study treats the nuclear industry in a state as a "unit" in which a variation of PEST analysis is implemented to reveal macro-environmental factors followed by SWOT analysis to identify strengths, weaknesses, opportunities and threats of available approaches, business models, legal and technical instruments. Four principal strategies emerge: (1) learning by doing; (2) transfer, adopt, assimilate, develop and export; (3) own or operate with limited transfer; and (4) wait and see. The first two strategies are proposed for the countries willing to launch an ambitious nuclear power program. Own or operate with limited transfer strategy can be deployed in those countries prioritizing security of supply, source of reliable base load generation, general economic development, technological and qualified human resources development. Wait and see strategy is convenient for those countries awaiting progress of new technologies or phased out nuclear power but planning to reintroduce it in the future. Regardless of the strategy selected, wise guiding policies and coherent set of actions must be deployed for a successful assimilation and acquisition of the design,Science Citation Index Expande
The Distribution of Wind Power from a Dispersed Array of Wind Turbine Generators and Its Reliability Based Applications
No full textIn this paper, the probability distribution of wind power from a dispersed array of wind turbine sites is studied considering forced outage rates of wind turbines. The wind speeds at distinct sites are assumed to be dependent and the dependence is modeled by copulas. In particular, the probability distribution of the aggregate power from two sites is exactly derived. The probability distribution of the aggregate power is also derived under the particular case when site 1 consists of n1 identical wind turbines of type 1 and site 2 consists of n2 identical wind turbines of type 2. Numerical results are presented to illustrate the theoretical findings for a chosen copula function
Comparative Analysis of Vibration Axis Effects on Ultrasonic Vibration-Assisted Machining of Inconel 718
No full textInconel 718 is widely utilized in critical engineering sectors, particularly aerospace, owing to its exceptional creep resistance, corrosion resistance, and retention of mechanical strength at elevated temperatures. However, its high hardness, low thermal conductivity, and strong work-hardening tendency make it extremely difficult to machine using conventional techniques. Ultrasonic Vibration-Assisted Machining (UVAM) has emerged as an effective strategy to overcome these limitations by superimposing high-frequency, low-amplitude vibrations onto the cutting process. Depending on the vibration direction, UVAM can significantly change chip formation, tool-workpiece interaction, and surface integrity. In this study, the influence of three UVAM modes-longitudinal (Z-UVAM), feed-directional (X-UVAM), and multi-axial (XZ-UVAM)-on the machining behavior of Inconel 718 was systematically investigated. The findings reveal that XZ-UVAM provides the most advantageous outcomes, primarily due to its intermittent cutting mechanism. Compared with Conventional Machining (CM), XZ-UVAM reduced cutting forces by up to 43% and areal surface roughness by 37%, while generating surfaces with more uniform topographies and smaller peak-to-valley variations. Furthermore, UVAM enhanced subsurface microhardness as a result of the surface hammering effect, which may improve fatigue performance. XZ-UVAM also effectively minimized burr formation, demonstrating its potential for high-quality, sustainable, and efficient machining of Inconel 718.The Scientific and Technological Research Council of Turkey (TUBITAK) [22M381]This research was funded by The Scientific and Technological Research Council of Turkey (TUBITAK), grant number 22M381