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Department: search.filters.department.Department of Electrical and Electronics EngineeringSubject: search.filters.subject.Computer architecture

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Now showing 1 - 10 of 21
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    Broadcasting brake lights with MIMO-OFDM based vehicular VLC
    (IEEE Computer Society, 2016) Narmanloğlu, Ömer; Uysal, Murat; N/A; Department of Electrical and Electronics Engineering; Turan, Buğra; Ergen, Sinem Çöleri; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 7211
    Inter-vehicular connectivity to enhance road safety and enable highly autonomous driving is increasingly becoming popular. Despite the prevalent works on radio-frequency (RF) based vehicular communication schemes, visible light communication (VLC) is considered to be a promising candidate for vehicular communications due to its low complexity and RF interference-free nature. This paper investigates applicability of VLC to enhance road safety based on real world measurements. Deployment of multiple light emitting diodes (LEDs) enables multiple-input multiple-output (MIMO) transmission in the context of vehicular VLC. We consider direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM) based MIMO transmission scheme and evaluate the performances of different MIMO modes including repetition code (RC) and spatial multiplexing (SM), different modulation orders and different transmitter-receiver selection. The results reveal that selection of the closest transmitters to the receivers, provide better performance due to high signal-to-noise-ratio (SNR) requirements for RC mode. However, usage of all possible transmitters does not always yield better performance due to power division at the transmitter side. Moreover, SM suffers from channel correlation whereas the performance of RC shows more degradation on higher-order modulations that are required to yield the same throughput with SM.
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    Data-driven abnormal behavior detection for autonomous platoon
    (IEEE Computer Society, 2018) N/A; Department of Electrical and Electronics Engineering; Department of Computer Engineering; Uçar, Seyhan; Ergen, Sinem Çöleri; Özkasap, Öznur; PhD Student; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Department of Computer Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; 7211; 113507
    Autonomous platoon is a technique where co-operative adaptive cruise control (CACC) enabled vehicles are organized into groups of close following vehicles through communication. It is envisioned that with the increased demand for autonomous vehicles, platoons would be a part of our life in near future. Although many efforts have been devoted to implement the vehicle platooning, ensuring the security remains challenging. Due to lack of security, platoons would be subject to modified packets which can mislead the platoon and result in platoon instability. Therefore, identifying malicious vehicles has become an important requirement. In this paper, we investigate a data-driven abnormal behavior detection approach for an autonomous platoon. We propose a novel statistical learning based technique to detect data anomalies. We demonstrate that shared speed value among platoon members would be sufficient to detect the misbehaving vehicles.
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    Dimming support for visible light communication in intelligent transportation and traffic system
    (Ieee, 2016) N/A; N/A; Department of Electrical and Electronics Engineering; Department of Computer Engineering; Department of Electrical and Electronics Engineering; Uçar, Seyhan; Turan, Buğra; Ergen, Sinem Çöleri; Özkasap, Öznur; Ergen, Mustafa; PhD Student; PhD Student; Faculty Member; Faculty Member; Faculty Member; Department of Computer Engineering; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; College of Engineering; N/A; N/A; 7211; 113507; N/A
    The automotive industry is under a major change and new vehicles are being enriched by the recent advances in communication. Not only business plans are changing due to connected and urbanized lifestyle, but also transportation is becoming more intelligent with smart roads that connect smart cars. Technology coined as the vehicular ad-hoc network (VANET) is harmonizing with Intelligent Transportation System (ITS) and Intelligent Traffic System (ITF). However, ITS and ITF systems suffer from the scarcity of radio frequency spectrum. Visible light communication (VLC) that uses modulated optical radiation in the visible light spectrum is an alternative medium being researched. To date, the majority of research on vehicular VLC was aimed at achieving high data rates provided that high lighting quality is achieved without any concern on dimmable LED lights. Auto-dimmable headlights gain attention due to danger caused by sudden glare on drivers at night conditions which makes dimming in VLC necessary. In this paper, we first present the latest concept of vehicular VLC on ITS and ITF systems and address dimming utility. We then demonstrate experimentally that dimming is a key parameter in VLC which affects data dissemination and received power signal strength.
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    Dimming support for visible light communication in intelligent transportation and traffic system
    (Institute of Electrical and Electronics Engineers (IEEE), 2016) N/A; N/A; Department of Electrical and Electronics Engineering; Department of Computer Engineering; Department of Electrical and Electronics Engineering; Uçar, Seyhan; Turan, Buğra; Ergen, Sinem Çöleri; Özkasap, Öznur; Ergen, Mustafa; PhD Student; PhD Student; Faculty Member; Faculty Member; Faculty Member; Department of Computer Engineering; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; College of Engineering; N/A; N/A; 7211; 113507; N/A
    The automotive industry is under a major change and new vehicles are being enriched by the recent advances in communication. Not only business plans are changing due to connected and urbanized lifestyle, but also transportation is becoming more intelligent with smart roads that connect smart cars. Technology coined as the vehicular ad-hoc network (VANET) is harmonizing with Intelligent Transportation System (ITS) and Intelligent Traffic System (ITF). However, ITS and ITF systems suffer from the scarcity of radio frequency spectrum. Visible light communication (VLC) that uses modulated optical radiation in the visible light spectrum is an alternative medium being researched. To date, the majority of research on vehicular VLC was aimed at achieving high data rates provided that high lighting quality is achieved without any concern on dimmable LED lights. Auto-dimmable headlights gain attention due to danger caused by sudden glare on drivers at night conditions which makes dimming in VLC necessary. In this paper, we first present the latest concept of vehicular VLC on ITS and ITF systems and address dimming utility. We then demonstrate experimentally that dimming is a key parameter in VLC which affects data dissemination and received power signal strength.
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    Distributed management of service-enabled flow-paths across multiple SDN domains
    (IEEE, 2015) Civanlar, Seyhan; Lokman, Erhan; Kaytaz, Bülent; Department of Electrical and Electronics Engineering; Tekalp, Ahmet Murat; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 26207
    Future Internet may be comprised of interconnected multiple software-defined networks (SDN), where each domain is administered by a different controller or control plane. Provisioning of an end-to-end flow-path across such a network with specific service levels requires collaboration between domain controllers across control planes. A service-enabled flow-path shall be quality of service (QoS) enabled, reliable and/or secure, which requires a transport path with certain quantitative service level requirements such as high throughput, low packet loss, or high availability. Each SDN controller can autonomously determine such end-to-end flow-paths when all other SDN controllers periodically advertise to other controllers its available service-enabled paths. Doing so, each SDN controller is presented with several service-enabled path alternatives, crossing other domains, to choose from. We propose a multi-domain SDN controller design, wherein each SDN controller shares its network's "summarized" topology of service-enabled paths with other SDN controllers, such that all domains (controllers) have real-time autonomous decision making capability for end-to-end flow-path selection. We also describe how an SDN controller can reserve and release a flow traversing other SDN domains.
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    Dynamic management of control plane performance in software-defined networks
    (Institute of Electrical and Electronics Engineers (IEEE), 2016) Görkemli, Burak; Parlakışık, A. Murat; Civanlar, Seyhan; Ulaş, Aydın; Department of Electrical and Electronics Engineering; Tekalp, Ahmet Murat; Faculty Member; Department of Electrical and Electronics Engineering; College of Engineering; 26207
    The controller or the control plane is at the heart of software defined networks (SDN). As SDN migrates to wide area networks (WAN), scalability and performance are two important factors that differentiate one controller from another, and they are critical for success of SDN for end-to-end service management. We distinguish control flows from data flows, and introduce a novel dynamic control plane architecture to distribute different control flows among multiple controller instances depending on specific controller load and controller processor utilization or on the data flow service type. We propose control flow tables - a concept introduced in this paper - that are embedded in OpenFlow flow tables to distribute the control flows among various controller instances. Experimental results demonstrate the improvements in the data plane service performance as a result of the proposed control flow management procedures when the bottleneck is the controller CPU or throughput of links between the controller and switches.
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    Employing 60 GHz ISM band for 5G wireless communications
    (IEEE, 2014) Fadel, Etimad; N/A; Department of Electrical and Electronics Engineering; Yılmaz, Türker; Akan, Özgür Barış; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 6647
    Wireless data traffic is continuously increasing due to the steady rise in both connected device number and traffic per device. Wireless networks, traditionally confined below 6 giga-hertz, are getting clogged and unable to satisfy the ever-increasing demands of its users. Already aware of this, telecommunications industry and academia have been working on solutions. One of the main methods for throughput increase is operation bandwidth expansion; however, sufficient spectrum is not available within the conventional frequencies. Following various considerations, 60 GHz industrial, scientific and medical radio band has been selected as the new spectrum to be utilized and wireless personal and local area network standards for the band are already completed. In line with the stated developments, this paper proposes the use of 60 GHz band for the fifth generation (5G) communication systems. After very briefly setting the scene of the current wireless communication networks, the physical layer properties of the 60 GHz band are presented. A representative indoor simulation between the fourth generation and proposed 5G cases is set and performed. The results are assessed and compared before concluding the paper.
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    Exploring projection based mixed reality with tangibles for nonsymbolic preschool math education
    (Assoc Computing Machinery, 2019) N/A; N/A; Department of Psychology; Department of Media and Visual Arts; Department of Electrical and Electronics Engineering; Salman, Elif; Beşevli, Ceylan; Göksun, Tilbe; Özcan, Oğuzhan; Ürey, Hakan; Master Student; Researcher; Faculty Member; Faculty Member; Faculty Member; Department of Psychology; Department of Media and Visual Arts; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Social Sciences and Humanities; College of Social Sciences and Humanities; College of Social Sciences and Humanities; College of Engineering; N/A; N/A; 47278; 12532; 8579
    A child's early math development can stem from interactions with the physical world. Accordingly, current tangible interaction studies focus on preschool children's formal (symbolic) mathematics, i.e. number knowledge. However, recent developmental studies stress the importance of nonsymbolic number representation in math learning, i.e. understanding quantity relations without counting(more/less). To our knowledge, there are no tangible systems based on this math concept. We developed an initial tangible based mixed-reality(MR) setup with a small tabletop projector and depth camera. Our goal was observing children's interaction with the setup to guide our further design process towards developing nonsymbolic math trainings. In this paper we present our observations from sessions with four 3-to-5 year old children and discuss their meaning for future work. Initial clues show that our MR setup leads to exploratory and mindful interactions, which might be generalizable to other tangible MR systems for child education and could inspire interaction design studies.
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    Millimetre wave communication for 5G iot applications
    (Springer International Publishing Ag, 2016) N/A; N/A; Department of Electrical and Electronics Engineering; Yılmaz, Türker; Gökkoca, Gökçe; Akan, Özgür Barış; PhD Student; Master Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Social Sciences and Humanities; College of Engineering; N/A; N/A; 6647
    Mobile communications industry is going through an era of very rapid advancement as multiple major innovations are about to take place. Fifth generation (5G) of mobile communication systems is developed to become an all-encompassing solution to fundamentally every broadband wireless communication need of the next decade. Since both the communication and electronic technologies are matured enough, machine-to-machine communication is also about to take off, placing a completely new set of demands on the wireless networks. As the spectrum is already limited in the conventional sub 6 GHz bands, in order to generate efficient applications for the Internet of Things (IoT) within the 5G systems, utilization of new frequency bands are needed. Comprising, both licensed and unlicensed, ample bandwidth, millimetre wave (mm-wave) band is the primary candidate for adoption. In line with these, in this chapter mm-wave band is analyzed for use in 5G IoT implementations. Subsequent to introduction, a brief description of mm-wave band channel characteristics is provided. Then, enabling physical layer techniques of modulation, error control coding and multiple input multiple output are reviewed from the 5G mm-wave point of view. Following conclusions, the chapter ends with open research issues and future research directions.
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    Minimum length scheduling for wireless powered communication networks with discrete rates
    (IEEE, 2020) N/A; Department of Electrical and Electronics Engineering; Salık, Elif Dilek; Ergen, Sinem Çöleri; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 7211
    Radio frequency energy harvesting is an alternative solution to power the next generation wireless networks. the vast majority of the existing works focus on continuous rate transmission model, Although discrete rate model is more realistic for practical communication networks. We study the joint optimization of energy harvesting and information transmission times with the objective of minimizing the total schedule length of a multi-user, harvest-then-transmit, wireless powered communication network while following discrete Signal-to-Noise Ratio and rate transmission model. the users are required to transmit a minimum amount of data to the access point under a maximum transmit power limit. the formulated problem is mixed integer, non-linear and non-convex. First, we solve the case where the rate allocations are given. then, we exploit given rate allocation problem's optimality characteristics to achieve the global optimal solution for the original problem. We propose an exponential time optimal algorithm which exhibits practical superiority to the brute force algorithm, and two polynomial time heuristics, one of which prioritizes minimizing information transmission times, while the other focuses on improving energy harvesting time. Performances of the proposed algorithms are compared both to an algorithm which assigns continuous rates to the user, i.e., best lower bound, and to an algorithm which discretize the former continuous rate solution. Simulation results show that the proposed heuristic algorithms perform close to the optimal solution, and the proposed algorithms outperform the algorithm that discretize the continuous rate solution up to 56:9% for smaller access point power and 46:7% for higher number of users. This proves the importance of optimizing the total schedule length for discrete rate model as the users will be forced to transmit at discrete rates practically.