Erol Özçelik

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Papers by Erol Özçelik

Fusion of smartphone sensor data for classification of daily user activities

Multimedia Tools and Applications, 2021

New mobile applications need to estimate user activities by using sensor data provided by smart w... more New mobile applications need to estimate user activities by using sensor data provided by smart wearable devices and deliver context-aware solutions to users living in smart environments. We propose a novel hybrid data fusion method to estimate three types of daily user activities (being in a meeting, walking, and driving with a motorized vehicle) using the accelerometer and gyroscope data acquired from a smart watch using a mobile phone. The approach is based on the matrix time series method for feature fusion, and the modified Better-than-the-Best Fusion (BB-Fus) method with a stochastic gradient descent algorithm for construction of optimal decision trees for classification. For the estimation of user activities, we adopted a statistical pattern recognition approach and used the k-Nearest Neighbor (kNN) and Support Vector Machine (SVM) classifiers. We acquired and used our own dataset of 354 min of data from 20 subjects for this study. We report a classification performance of 98...

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The Effect of Training, Used-Hand, and Experience on Endoscopic Surgery Skills in an Educational Computer-Based Simulation Environment (ECE) for Endoneurosurgery Training

Surgical Innovation, 2019

Today, virtual simulation environments create alternative hands-on practice opportunities for sur... more Today, virtual simulation environments create alternative hands-on practice opportunities for surgical training. In order to increase the potential benefits of such environments, it is critical to understand the factors that influence them. This study was conducted to determine the effects of training, used-hand, and experience, as well as the interactions between these variables, on endoscopic surgery skills in an educational computer-based surgical simulation environment. A 2-hour computer-based endoneurosurgery simulation training module was developed for this study. Thirty-one novice- and intermediate-level resident surgeons from the departments of neurosurgery and ear, nose, and throat participated in this experimental study. The results suggest that a 2-hour training during a 2-month period through computer-based simulation environment improves the surgical skills of the residents in both-hand tasks, which is necessary for endoscopic surgical procedures but not in dominant han...

The Underlying Reasons of the Navigation Control Effect on Performance in a Virtual Reality Endoscopic Surgery Training Simulator

International Journal of Human–Computer Interaction, 2018

ABSTRACT Navigation control skills of surgeons become very critical for surgical procedures. Stra... more ABSTRACT Navigation control skills of surgeons become very critical for surgical procedures. Strategies improving these skills are important for developing higher-quality surgical training programs. In this study, the underlying reasons of the navigation control effect on performance in a virtual reality-based navigation environment are evaluated. The participants’ performance is measured in conditions: navigation control display and paper-map display. Performance measures were collected from 45 beginners and experienced residents. The results suggest that navigation display significantly improved performance of the participants. Also, navigation was more beneficial for beginners than experienced participants. The underlying reason of the better performance in the navigation condition was due to lower number of looks to the map, which causes attention shifts between information sources. Accordingly, specific training scenarios and user interfaces can be developed to improve the navigation skills of the beginners considering some strategies to lower their number of references to the information sources.

Insights From Pupil Size to Mental Workload of Surgical Residents: Feasibility of an Educational Computer-Based Surgical Simulation Environment (ECE) Considering the Hand Condition

Surgical innovation, Jan 12, 2018

The advantage of simulation environments is that they present various insights into real situatio... more The advantage of simulation environments is that they present various insights into real situations, where experimental research opportunities are very limited-for example, in endoscopic surgery. These operations require simultaneous use of both hands. For this reason, surgical residents need to develop several motor skills, such as eye-hand coordination and left-right hand coordination. While performing these tasks, the hand condition (dominant, nondominant, both hands) creates different degrees of mental workload, which can be assessed through mental physiological measures-namely, pupil size. Studies show that pupil size grows in direct proportion to mental workload. However, in the literature, there are very limited studies exploring this workload through the pupil sizes of the surgical residents under different hand conditions. Therefore, in this study, we present a computer-based simulation of a surgical task using eye-tracking technology to better understand the influence of t...

Construct and face validity of the educational computer-based environment (ECE) assessment scenarios for basic endoneurosurgery skills

Surgical Endoscopy, 2017

In neurosurgery education, there is a paradigm shift from time-based training to criterion-based ... more In neurosurgery education, there is a paradigm shift from time-based training to criterion-based model for which competency and assessment becomes very critical. Even virtual reality simulators provide alternatives to improve education and assessment in neurosurgery programs and allow for several objective assessment measures, there are not many tools for assessing the overall performance of trainees. This study aims to develop and validate a tool for assessing the overall performance of participants in a simulation-based endoneurosurgery training environment. A training program was developed in two levels: endoscopy practice and beginning surgical practice based on four scenarios. Then, three experiments were conducted with three corresponding groups of participants (Experiment 1, 45 (32 beginners, 13 experienced), Experiment 2, 53 (40 beginners, 13 experienced), and Experiment 3, 26 (14 novices, 12 intermediate) participants). The results analyzed to understand the common factors among the performance measurements of these experiments. Then, a factor capable of assessing the overall skill levels of surgical residents was extracted. Afterwards, the proposed measure was tested to estimate the experience levels of the participants. Finally, the level of realism of these educational scenarios was assessed. The factor formed by time, distance, and accuracy on simulated tasks provided an overall performance indicator. The prediction correctness was very high for the beginners than the one for experienced surgeons in Experiments 1 and 2. When non-dominant hand is used in a surgical procedure-based scenario, skill levels of surgeons can be better predicted. The results indicate that the scenarios in Experiments 1 and 2 can be used as an assessment tool for the beginners, and scenario-2 in Experiment 3 can be used as an assessment tool for intermediate and novice levels. It can be concluded that forming the balance between perceived action capacities and skills is critical for better designing and developing skill assessment surgical simulation tools.

Personality type indicator models in serious games: A case study in a surgical navigation game

2015 International Conference on Information Technology Based Higher Education and Training (ITHET), 2015

Serious games are a popular concept in both the research and commercial areas. It is agreed that ... more Serious games are a popular concept in both the research and commercial areas. It is agreed that the concept refers to the use of computer games without the main purpose of pure entertainment. In addition to being entertaining, they have some additional educational or training objectives as well. Serious games are used in different areas such as military, government, educational, corporate, and healthcare. However, according to their individual differences, it is not always possible to provide such an educational environment that fits expectations and preferences of all audience. Hence, personalization is becoming an essential issue in serious game environments, which focus on a human-centered paradigm aiming to provide adaptive and personalized services to the users according to the context. However, how such a personalization should be affectively implemented in the design of serious games is a challenge. This study aims to better understand the affect of personality types on game play. For this purpose, a game-based simulation environment which also records all details of the player during the performance of several tasks in the game play was used. Twenty nine students were asked to play the simulation game. Additionally, their personality types were collected based on the theory of psychological types by Carl Jung, the Myers-Briggs Type Indicator (MBTI) which measures personality preferences as defined by Four Dichotomous pairs of mental functions or attitudes. The correlation between these personality types and individual performance measures of players during the game play was analyzed. However no significant correlation between game parameters and the players' personality types has been recorded. This may be because of the limited number of participants that need to be examined in the future studies.

The Effect of Split Attention in Surgical Education

Lecture Notes in Computer Science, 2014

Surgical education through simulation is an important area to improve the level of education and ... more Surgical education through simulation is an important area to improve the level of education and to decrease the risks, ethical considerations and cost of the educational environments. In the literature there are several studies conducted to better understand the effect of these simulation environments on learning. However among those studies the human-computer interaction point of view is very limited. Surgeons need to look at radiological images such as magnetic resonance images (MRI) to be sure about the location of the patient's tumor during a surgical operation. Thus, they go back and forth between physically separated places (e.g. the operating table and light screen display for MRI volume sets). This study is conducted to investigate the effect of presenting different information sources in close proximity on human performance in surgical education. For this purpose, we have developed a surgical education simulation scenario which is controlled by a haptic interface. To better understand the effect of split attention in surgical education, an experimental study is conducted with 27 subjects. The descriptive results of study show that even the integrated group performed the tasks with a higher accuracy level (by traveling less distance, entering less wrong directions and hitting less walls), the results are not statistically significant. Accordingly, even there are some evidences about the effect of split attention on surgical simulation environments, the results of this study need to be validated by controlling students' skill levels on controlling the haptic devices and 2D/3D space perception skills. The results of this study may guide the system developers to better design the HCI interface of their designs especially for the area of surgical simulation.

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Estimation of Polypropylene Concentration of Modified Bitumen Images by Using k-NN and SVM Classifiers

Journal of Computing in Civil Engineering, 2015

ABSTRACT The goal of this study is to design an expert system that automatically classifies the m... more ABSTRACT The goal of this study is to design an expert system that automatically classifies the microscopic images of polypropylene fiber (PPF) modified bitumen including seven different contents of fibers. Optical microscopy was used to capture the images from thin films of polypropylene fiber modified bitumen samples at a magnification scale of 100 ×. A total of 313 images were pre-processed, and features were extracted and selected by the exhaustive search method. The k-nearest neighbor (k-NN) and multiclass support vector machine (SVM) classifiers were applied to quantify the representation capacity. The k-NN and multiclass SVM classifiers reached an accuracy rate of 87% and 86%, respectively. The results suggest that the proposed expert system can successfully estimate the concentration of PPF in bitumen images with good generalization characteristics. 11 Engineers.

The effect of uncertainty on learning in game-like environments

Computers & Education, 2013

Considering the role of games for educational purposes, there has an increase in interest among e... more Considering the role of games for educational purposes, there has an increase in interest among educators in applying strategies used in popular games to create more engaging learning environments. Learning is more fun and appealing in digital educational games and, as a result, it may become more effective. However, few research studies have been conducted to establish principles based on empirical research for designing engaging and entertaining games so as to improve learning. One of the essential characteristics of games that has been unexplored in the literature is the concept of uncertainty. This study examines the effect of uncertainty on learning outcomes. In order to better understand this effect on learning, a game-like learning tool was developed to teach a database concept in higher education programs of software engineering. The tool is designed in two versions: one including uncertainty and the other including no uncertainty. The experimental results of this study reveal that uncertainty enhances learning. Uncertainty is found to be positively associated with motivation. As motivation increases, participants tend to spend more time on answering the questions and to have higher accuracy in these questions.

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Gesture-based interaction for learning: time to make the dream a reality

British Journal of Educational Technology, 2012

Introduction Research studies have shown that individuals who make hand gestures learn better tha... more Introduction Research studies have shown that individuals who make hand gestures learn better than the ones who do not (eg, Alibali & Goldin-Meadow, 1993; Broaders, Cook, Mitchell & Goldin-Meadow, 2007). For instance, when children use their hands while they are explaining how they solve mathematical equivalence problems (eg, 6 + 4 +5 = _ + 5), they perform better in post-tests (Broaders et al, 2007). Comprehension and, consequently, memory are improved by these acts (Stevanoni & Salmon, 2005). In addition, gestures facilitate deep and long-lasting learning (Cutica & Bucciarelli, 2008).

Why does signaling enhance multimedia learning? Evidence from eye movements

Computers in Human Behavior, 2010

Previous studies have suggested that signaling enhances multimedia learning. However, there is no... more Previous studies have suggested that signaling enhances multimedia learning. However, there is not 20 enough evidence showing why signaling leads to better performance. The goal of this study was to exam-21 ine the effects of signaling on learning outcomes and to reveal the underlying reasons for this effect by 22 using eye movement measures. The participants were 40 undergraduate students who were presented 23 with either signaled or nonsignaled multimedia materials. Labels in the illustration were signaled by 24 temporarily changing the color of the items. The results suggest that the signaled group outperformed 25 the nonsignaled group on transfer and matching tests. Eye movement data shows that signaling guided 26 attention to relevant information and improved the efficiency and effectiveness of finding necessary 27 information. 28

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An eye-tracking study of how color coding affects multimedia learning

Computers & Education, 2009

Color coding has been proposed to promote more effective learning. However, insufficient evidence... more Color coding has been proposed to promote more effective learning. However, insufficient evidence currently exists to show how color coding leads to better learning. The goal of this study was to investigate the underlying cause of the color coding effect by utilizing eye movement data. Fifty-two participants studied either a color-coded or conventional format of multimedia instruction. Eye movement data were collected during the study. The results indicate that color coding increased retention and transfer performance. Enhancement of learning by color coding was due to efficiency of locating corresponding information between illustration and text. Color coding also attracted attention of learners to perceptually salient information.

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The effect of competition on learning in games

Computers & Education, 2015

Today serious games are having an important impact on areas other than entertainment. Studies sho... more Today serious games are having an important impact on areas other than entertainment. Studies show that serious games have a potential of creating learning environments to better reach the educational and training goals. The game design characteristics and game elements are need to be explored in detail for increasing the expected benefits of the gaming environments. In this study, the effect of competition, one of the design elements of game environments, on learning is analyzed experimentally. The study is conducted with 142 students. The results of this study show that when a competition environment is created in a serious game, motivation and post-test scores of learners improve significantly. The results of this study are expected to guide the serious game designers for improving the potential benefits of serious games.

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Simulation-Based Environments for Surgical Practice

by Nergiz Cagiltay, Erol Özçelik, and Gonca Gokce Menekse Dalveren

—Modeling and simulation environments provide several insights about the real situations such as ... more —Modeling and simulation environments provide several insights about the real situations such as endoscopic surgery. Endoscopic surgery requires both hand skills, so, understanding the effect of using dominant or non dominant hand on mental workload is important to better design, develop and implement modeling and simulation environments to support real-life implementations of surgical procedures. This experimental study presents a simulation application of eye-tracking approach to understand mental workload in different hand conditions: dominant hand, non-dominant hand and both hand. The results of the study show that, performing simulated surgical tasks by both hands compared to dominant hand, increases mental workload which is evident by higher pupil size. Accordingly, to manage the mental-load problems of surgeons while performing complex tasks that require both hand usage simulation-based environments can be used. Consequently, collection of detailed information such as eye-data, can give several insights about the behaviors of the surgeons. Also, their required skills can be improved by development of simulation and training environments.

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