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Publication Open Access A novel haptic feature set for the classification of interactive motor behaviors in collaborative object transfer(Institute of Electrical and Electronics Engineers (IEEE), 2021) Küçükyılmaz, Ayşe; Department of Mechanical Engineering; Başdoğan, Çağatay; Şirintuna, Doğanay; Al-Saadi, Zaid Rassim Mohammed; Faculty Member; Department of Mechanical Engineering; College of Engineering; Graduate School of Sciences and Engineering; 125489; N/A; N/AHaptics provides a natural and intuitive channel of communication during the interaction of two humans in complex physical tasks, such as joint object transportation. However, despite the utmost importance of touch in physical interactions, the use of haptics is under-represented when developing intelligent systems. This article explores the prominence of haptic data to extract information about underlying interaction patterns within physical human-human interaction (pHHI). We work on a joint object transportation scenario involving two human partners, and show that haptic features, based on force/torque information, suffice to identify human interactive behavior patterns. We categorize the interaction into four discrete behavior classes. These classes describe whether the partners work in harmony or face conflicts while jointly transporting an object through translational or rotational movements. In an experimental study, we collect data from 12 human dyads and verify the salience of haptic features by achieving a correct classification rate over 91% using a Random Forest classifier.
Publication Metadata only A review of surface haptics: enabling tactile effects on touch surfaces(Institute of Electrical and Electronics Engineers (IEEE) Computer Society, 2020) Giraud, Frederic; Levesque, Vincent; Choi, Seungmoon; Department of Mechanical Engineering; Başdoğan, Çağatay; Faculty Member; Department of Mechanical Engineering; College of Engineering; 125489In this article, we review the current technology underlying surface haptics that converts passive touch surfaces to active ones (machine haptics), our perception of tactile stimuli displayed through active touch surfaces (human haptics), their potential applications (human-machine interaction), and finally, the challenges ahead of us in making them available through commercial systems. This article primarily covers the tactile interactions of human fingers or hands with surface-haptics displays by focusing on the three most popular actuation methods: vibrotactile, electrostatic, and ultrasonic.Publication Metadata only Adaptive human force scaling via admittance control for physical human-robot interaction(IEEE Computer Soc, 2021) Aydın, Yusuf; N/A; Department of Mechanical Engineering; Al Qaysi, Yahya Mohey Hamad; Başdoğan, Çağatay; PhD Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 125489The goal of this article is to design an admittance controller for a robot to adaptively change its contribution to a collaborative manipulation task executed with a human partner to improve the task performance. This has been achieved by adaptive scaling of human force based on her/his movement intention while paying attention to the requirements of different task phases. In our approach, movement intentions of human are estimated from measured human force and velocity of manipulated object, and converted to a quantitative value using a fuzzy logic scheme. This value is then utilized as a variable gain in an admittance controller to adaptively adjust the contribution of robot to the task without changing the admittance time constant. We demonstrate the benefits of the proposed approach by a pHRI experiment utilizing Fitts' reaching movement task. The results of the experiment show that there is a) an optimum admittance time constant maximizing the human force amplification and b) a desirable admittance gain profile which leads to a more effective co-manipulation in terms of overall task performance.Publication Metadata only An adaptive and diversified vehicle routing approach to reducing the security risk of cash-in-transit operations(Wiley, 2017) Bozkaya, Burçin; Department of Industrial Engineering; N/A; Salman, Fatma Sibel; Telciler, Kaan; Faculty Member; Master Student; Department of Industrial Engineering; College of Engineering; Graduate School of Sciences and Engineering; 178838; N/AWe consider the route optimization problem of transporting valuables in cash-in-transit (CIT) operations. The problem arises as a rich variant of the capacitated vehicle routing problem (CVRP) with time windows and pickup and deliveries. Due to the high-risk nature of this operation (e.g., robberies) we consider a bi-objective function where we attempt to minimize the total transportation cost and the security risk of transporting valuables along the designed routes. For risk minimization, we propose a composite risk measure that is a weighted sum of two risk components: (i) following the same or very similar routes, and (ii) visiting neighborhoods with low socioeconomic status along the routes. We also consider vehicle capacities in terms of monetary value carried as per insurance regulations. We develop an adaptive randomized bi-objective path selection algorithm that uses the composite risk measure in choosing alternative paths between origin-destination pairs over a sequence of days. We solve the rich CVRP approximately for each day with updated costs. We test our solution approach on a data set from a CIT delivery service provider and provide insights on how the routes diversify daily. Our approach generates a spectrum of solutions with costrisk trade-off to support decision making.Publication Metadata only An institutional perspective: how gatekeepers on a higher education interact for the organization of access(Springer, 2023) Department of Media and Visual Arts; Yıldız, Zeynep; Subaşı, Özge; Department of Media and Visual Arts; Graduate School of Social Sciences and HumanitiesThere is growing research on how collaborative systems could support equity in shaping access for marginalized communities in different contexts. Higher education institutions are essential contexts for examining issues around equity-based organization of access for diverse populations, including people with disabilities. However, there is a shortage of research in CSCW investigating equal access in higher education settings. To address this gap, in this case study, we aim to have a closer look at how gatekeepers (people who are responsible for accessibility) in a higher education institution organize access for members with disabilities. Gatekeeping has long been discussed in disability justice to examine systemic and institutional barriers for people with disabilities. We reveal how gatekeepers interact and collaborate around existing institutional communication channels to collect access-related requests and distribute access in the higher education setting. Our data shows that existing practices come with institutional challenges hindering equity and inclusion for members with disabilities. Key issues revealed through our findings are (1) communication tools and non-shared definitions around access, (2) lack of tools for experience documentation, (3) ineffective feedback loops around access requests, (4) impact-based prioritization for access requests. We discuss how our analysis contributes to equity-oriented system design for future collaboration around organizing higher education access at the institutional level.Publication Open Access An optoelectromechanical tactile sensor for detection of breast lumps(Institute of Electrical and Electronics Engineers (IEEE), 2013) Yıldız, Mustafa Zahid; Güçlü, Burak; Department of Mechanical Engineering; Başdoğan, Çağatay; Ayyıldız, Mehmet; Faculty Member; Master Student; Department of Mechanical Engineering; College of Engineering; 125489; N/AWe developed a compact tactile imaging (TI) system to guide the clinician or the self-user for noninvasive detection of breast tumors. Our system measures the force distribution based on the difference in stiffness between a palpated object and an abnormality within. The average force resolution, force range, and the spatial resolution of the device are 0.02 N, 0-4 N, and 2.8 mm, respectively. To evaluate the performance of the proposed TI system, compression experiments were performed to measure the sensitivity and specificity of the system in detecting tumor-like inclusions embedded in tissue-like cylindrical silicon samples. Based on the experiments performed with 11 inclusions, having two different sizes and two different stiffnesses located at three different depths, our TI system showed an average sensitivity of 90.8 +/- 8.1 percent and an average specificity of 89.8 +/- 12.7 percent. Finally, manual palpation experiments were performed with 12 human subjects on the same silicon samples and the results were compared to that of the TI system. The performance of the TI system was significantly better than that of the human subjects in detecting deep inclusions while the human subjects performed slightly better in detecting shallow inclusions close to the contact surface.Publication Open Access Analysis of push-type epidemic data dissemination in fully connected networks(Elsevier, 2014) Sezer, Ali Devin; Department of Mathematics; Çağlar, Mine; Faculty Member; Department of Mathematics; College of Sciences; 105131Consider a fully connected network of nodes, some of which have a piece of data to be disseminated to the whole network. We analyze the following push-type epidemic algorithm: in each push round, every node that has the data, i.e., every infected node, randomly chooses c E Z. other nodes in the network and transmits, i.e., pushes, the data to them. We write this round as a random walk whose each step corresponds to a random selection of one of the infected nodes; this gives recursive formulas for the distribution and the moments of the number of newly infected nodes in a push round. We use the formula for the distribution to compute the expected number of rounds so that a given percentage of the network is infected and continue a numerical comparison of the push algorithm and the pull algorithm (where the susceptible nodes randomly choose peers) initiated in an earlier work. We then derive the fluid and diffusion limits of the random walk as the network size goes to infinity and deduce a number of properties of the push algorithm: (1) the number of newly infected nodes in a push round, and the number of random selections needed so that a given percent of the network is infected, are both asymptotically normal, (2) for large networks, starting with a nonzero proportion of infected nodes, a pull round infects slightly more nodes on average, (3) the number of rounds until a given proportion lambda of the network is infected converges to a constant for almost all lambda is an element of (0, 1). Numerical examples for theoretical results are provided.Publication Metadata only BindMe: a thread binding library with advanced mapping algorithms(Wiley, 2018) N/A; Department of Computer Engineering; Department of Computer Engineering; Soomro, Pirah Noor; Sasongko, Muhammad Aditya; Erten, Didem Unat; PhD Student; Researcher; Faculty Member; Department of Computer Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; N/A; 219274Binding parallel tasks to cores according to a placement policy is one of the key aspects to achieve good performance in multicore machines because it can reduce on-chip communication among parallel threads. Binding also prevents operating system from migrating threads, which improves data locality. However, there is no single mapping policy that works best among all different kinds of applications and platforms because each machine has a different topology and each application exhibits different communication pattern. Determining the best policy for a given application and machine requires extra programming effort. To relieve the programmer from that burden, we introduce BindMe, A thread binding library that assists programmer to bind threads to underlying hardware. BindMe incorporates state-of-the-art mapping algorithms, which use communication pattern in an application to formulate an efficient task placement policy. We also introduce ChoiceMap, A communication aware mapping algorithm that respects mutual priorities of parallel tasks and performs a fair mapping by reducing communication volume among cores. We have tested BindMe and ChoiceMap with various applications from NaS parallel benchmark and Rodinia bechmark. Our results show that choosing a mapping policy that best suits the application behavior can increase its performance and no single policy gives the best performance across different applications.Publication Open Access Cyberphysical blockchain-enabled peer-to-peer energy trading(Institute of Electrical and Electronics Engineers (IEEE), 2020) Aloqaily, Moayad; Alfandi, Omar; N/A; Department of Computer Engineering; Ali, Faizan Safdar; Özkasap, Öznur; Faculty Member; Department of Computer Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 113507Scalability and security problems with centralized architecture models in cyberphysical systems have provided opportunities for blockchain-based distributed models. A decentralized energy-trading system takes advantage of various sources and effectively coordinates the energy to ensure the optimal utilization of available resources. Three blockchainbased energy-trading models are proposed to overcome the technical challenges and market barriers as well as enhance the adoption of this disruptive technology.Publication Metadata only Duty-cycle optimization for IEEE 802.15.4 wireless sensor networks(Assoc Computing Machinery, 2013) Park, Pangun; Fischione, Carlo; Sangiovanni-Vincentelli, Alberto; Department of Electrical and Electronics Engineering; Ergen, Sinem Çöleri; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 7211Most applications of wireless sensor networks require reliable and timely data communication with maximum possible network lifetime under low traffic regime. These requirements are very critical especially for the stability of wireless sensor and actuator networks. Designing a protocol that satisfies these requirements in a network consisting of sensor nodes with traffic pattern and location varying over time and space is a challenging task. We propose an adaptive optimal duty-cycle algorithm running on top of the IEEE 802.15.4 medium access control to minimize power consumption while meeting the reliability and delay requirements. Such a problem is complicated because simple and accurate models of the effects of the duty cycle on reliability, delay, and power consumption are not available. Moreover, the scarce computational resources of the devices and the lack of prior information about the topology make it impossible to compute the optimal parameters of the protocols. Based on an experimental implementation, we propose simple experimental models to expose the dependency of reliability, delay, and power consumption on the duty cycle at the node and validate it through extensive experiments. The coefficients of the experimental-based models can be easily computed on existing IEEE 802.15.4 hardware platforms by introducing a learning phase without any explicit information about data traffic, network topology, and medium access control parameters. The experimental-based model is then used to derive a distributed adaptive algorithm for minimizing the power consumption while meeting the reliability and delay requirements in the packet transmission. The algorithm is easily implementable on top of the IEEE 802.15.4 medium access control without any modifications of the protocol. An experimental implementation of the distributed adaptive algorithm on a test bed with off-the-shelf wireless sensor devices is presented. The experimental performance of the algorithms is compared to the existing solutions from the literature. The experimental results show that the experimental-based model is accurate and that the proposed adaptive algorithm attains the optimal value of the duty cycle, maximizing the lifetime of the network while meeting the reliability and delay constraints under both stationary and transient conditions. Specifically, even if the number of devices and their traffic configuration change sharply, the proposed adaptive algorithm allows the network to operate close to its optimal value. Furthermore, for Poisson arrivals, the duty-cycle protocol is modeled as a finite capacity queuing system in a star network. This simple analytical model provides insights into the performance metrics, including the reliability, average delay, and average power consumption of the duty-cycle protocol.