Researcher:
Koca, Çağlar

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PhD Student

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Çağlar

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Koca

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Koca, Çağlar

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2015 - 20184

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Researcher Of Publications: search.filters.isAuthorOfPublication.6a87dd2c-fedc-4934-93bc-21b86dabf491

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    Rate region analysis of multi-terminal neuronal nanoscale molecular communication channel
    (Institute of Electrical and Electronics Engineers (IEEE), 2017) Akan, Ozgur B.; N/A; N/A; Ramezani, Hamideh; Koca, Çağlar; PhD Student; PhD Student; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; N/A; N/A
    In this paper, we investigate the communication channel capacity among hippocampal pyramidal neurons. To this aim, we study the processes included in this communication and model them with realistic communication system components based on the existing reports in the physiology literature. We consider the communication between two neurons and reveal the effects of the existence of multiple terminals between these neurons on the achievable rate per spike. To this objective, we derive the power spectral density (PSD) of the signal in the output neuron and utilize it to calculate the rate region of the channel. Moreover, we evaluate the impacts of vesicle availability on the achievable rate by deriving the expected number of available vesicles in input neuron using a realistic vesicle release model. Simulation results show that number of available vesicles for release does not affect the achievable rate of neuro-spike communication with univesicular release model. However, in neurons that multiple vesicles can release from each synaptic terminal, achievable rate is significantly affected by depletion of vesicles. Moreover, we show that increasing the number of synaptic terminals between two neurons makes the synaptic connection stronger. Hence, it is an important factor in learning and memory, which occur in the hippocampal region of the brain based on the synaptic connectivity.
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    Anarchy versus cooperation on internet of molecular things
    (IEEE-Inst Electrical Electronics Engineers Inc, 2017) N/A; N/A; Department of Electrical and Electronics Engineering; Koca, Çağlar; 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
    Using the advances in molecular communications (MCs), nanomachines as a group can undertake complex tasks. With the emergence of Internet of molecular things (IoMT), such nanomachine groups are now larger than ever. However, the minimal design of nanomachines makes cooperation difficult. In this paper, we investigate the performances of anarchic and cooperative transmitters in IoMT. We design an MC game in which nanomachines choose to cooperate or confront. We discuss the advantages and disadvantages of cooperation and state the possible transmitter personalities using game theoretic principles. Moreover, we focus on methods to ensure cooperation and we explore the optimal transmitter behavior if its partner rejects cooperation. Finally, we deduce that although ensuring cooperation may be done effectively with minimum hardware, anarchy is not necessarily a bad result. We also realize that in case a transmitter rejects cooperation, perpetual confrontation is not a good approach.
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    Quantum memory management systems
    (Association for Computing Machinery, Inc, 2015) Department of Electrical and Electronics Engineering; N/A; Akan, Özgür Barış; Koca, Çağlar; Faculty Member; PhD Student; Department of Electrical and Electronics Engineering; College of Engineering; Graduate School of Sciences and Engineering; 6647; N/A
    Quantum computation is a developing area in science. Owing to the new developments in nanotechnology, some practical quantum computing applications are emerging. Even though quantum computation possesses many inherent superiorities, it suffer from a tight bottleneck: Quantum Storage. In this paper, we identify properties of a good quantum storage unit and propose unique quantum memory structures and discuss them in terms of circuit complexity, access delay complexity, maximum connectivity and ancillary qubits required. We reveal that quantum teleportation provide advantage only in maximum connectivity among the properties we analyzed. © 2015 ACM.
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    PublicationOpen Access
    Internet of hybrid energy harvesting things
    (Institute of Electrical and Electronics Engineers (IEEE), 2018) Department of Electrical and Electronics Engineering; Akan, Özgür Barış; Çetinkaya, Oktay; Koca, Çağlar; Özger, Mustafa; Faculty Member; Researcher; PhD Student; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering
    Internet of Things (IoT) is a perfect candidate to realize efficient observation and management for Smart City concept. This requires deployment of large number of wireless devices. However, replenishing batteries of thousands, maybe millions of devices may be hard or even impossible. In order to solve this problem, Internet of Energy Harvesting Things (IoEHT) is proposed. Although the first studies on IoEHT focused on energy harvesting (EH) as an auxiliary power provisioning method, now completely battery-free and self-sufficient systems are envisioned. Taking advantage of diverse sources that the concept of Smart City offers helps us to fully appreciate the capacity of EH. In this way, we address the primary shortcomings of IoEHT; availability, unreliability, and insufficiency by the Internet of Hybrid EH Things (IoHEHT). In this paper, we survey the various EH opportunities, propose an hybrid EH system, and discuss energy and data management issues for battery-free operation. We mathematically prove advantages of hybrid EH compared to single source harvesting as well. We also point out to hardware requirements and present the open research directions for different network layers specific to IoHEHT for Smart City concept.