Browsing by Subject "heterogeneous"

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    An Enhanced Heterogeneous Gateway-Based Energy-Aware Multi-Hop Routing Protocol for Wireless Sensor Networks
    (2022-03-25) Jibreel, Fuseini; Tuyishimire, Emmanuel; Daabo, Mohammed Ibrahim
    Wireless Sensor Networks (WSNs) continue to provide essential services for various applications such as surveillance, data gathering, and data transmission from hazardous environments to safer destinations. This has been enhanced by the energy-efficient routing protocols that are mostly designed for such purposes. Gateway-based Energy-Aware Multi-hop Routing protocol (MGEAR) is one of the homogenous routing schemes that was recently designed to more efficiently reduce the energy consumption of distant nodes. However, it has been found that the protocol has a high energy consumption rate, lower stability period, and poorer data transmission to the Base station (BS) when it was deployed for a longer period of time. In this paper, an enhanced Heterogeneous Gateway-based Energy-Aware multi-hop routing protocol (HMGEAR) is proposed. The proposed routing scheme is based on the introduction of heterogeneous nodes in the existing scheme, selection of the head based on the residual energy, introduction of multi-hop communication strategy in all the regions of the network, and implementation of energy hole elimination technique. All these strategies are aiming at reducing energy consumption and extend the life of the network. Results show that the proposed routing scheme outperforms two existing ones in terms of stability period, throughputs, residual energy, and the lifetime of the network.
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    The gas content of luminous compact blue galaxies in the COSMOS field
    (2024) Arlow, Henco; Pisano, Daniel J; Bershady, Matthew
    Luminous compact blue galaxies (LCBGs) are a heterogeneous subset of starburst galaxies. Their number density drops quite significantly as we approach lower redshifts. As a set of galaxies that evolve quickly, they make excellent candidates for studying galactic evolution as a whole. In order to understand how galaxies evolve, we make use of LCBGs to study their gas content as it changes over approximately nine billion years of lookback time. We make use of HI emission line data provided by the full CHILES survey, covering a redshift range of z=0 to z=0.45 within the COSMOS f ield as well as continuum data of the same field provided by the CHILES Continuum Polarization survey. In this thesis we set out to study the properties of LCBGs in these f ields to better understand the nature of these objects as they evolve to the present day. We report on direct detections of HI found in LCBGs in CHILES.Wealsoperform acubelet stacking technique on LCBGs for which we have known spectroscopic redshifts in CHILES. From these stacks we measure average HI masses as well as upper limit values for non-detections to study how it evolves with redshift. We also measure the star formation rates of a set of LCBGs using continuum fluxes in CHILES Con Pol and compare our results to measurements made with data from CHILES's first epoch. Continuum stacking is then performed in several redshift and stellar mass bins to extract average star formation rates. We proceed to fit appropriate functions to these relations in order to quantify the dependence of LCBG sSFRs to their stellar mass and redshift.