Browsing by Subject "Storage"
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Item Assessing the role of culvert sediment storage an urbanized watershed(2023-01-01) Chase, Jason Hamilton; Miller, Andrew J; Geography and Environmental Systems; Geography and Environmental SystemsWatershed urbanization has profound impacts on sediment dynamics. Land development introduces novel pathways of sediment storage and remobilization to the stream environment, notably in the form of culverts. This study sought to contextualize the role of culvert sediment storage and remobilization through the lens of fluvial geomorphology and to explore the interaction of culverts with sediment dynamics in an urbanized watershed. This was performed by assessing characteristics of culvert sites that influence sediment storage and by comparing the quantity and type of sediment stored in culverts to sediment associated with other forms of storage and sediment transport. A combination of remote- and field-based techniques were used to study culvert sediment storage, natural sediment storage in channel bar deposits, channel erosion, and sediment storage and remobilization associated with high-magnitude precipitation events in the heavily urbanized Dead Run watershed near Baltimore, Maryland. Additional data sourced from a previous study in this watershed were also included to incorporate analyses of suspended sediment transport.The total mass of sediment stored throughout culvert sites in Dead Run was 749 metric tons. Regression analyses performed using sediment storage mass and culvert site characteristics indicated that storage was driven by culvert size and slope, though the predominant factor was the degree of slope change as the stream channel enters the culvert. This result suggests that the alteration of hydraulic conditions at the culvert is the primary driver of culvert sediment deposition. Comparisons of sediment size fractioned-masses from culverts to those of other geomorphic features and processes also suggested that, while culverts predominantly stored coarse sediment at approximately 50% sand and 47.5% gravel, culverts stored proportionally more sand and fine sediment compared to natural channel bars (around 0.3 tons per meter of channel length). Culvert deposits showed different responses to large precipitation events and associated high flows, with net sediment storage and remobilization occurring across different sites. However, fine sediment in culverts was observed to be in overall lower abundance throughout the watershed following the storm events, with an average loss of very fine sediment (<125 µm) at 68%. Overall, it can be inferred from this study that culvert sediment storage is primarily induced by alterations to local hydraulic conditions, though the ways in which culvert sediment is stored and remobilized vary depending on sediment size. Culvert sediment storage was observed to be quite dynamic regarding both magnitude and sediment size over the short time scale of this study Ð a trend that warrants further investigation and incorporation of this form of storage into broader-scale urban sediment studies.Item The Lightweight Virtual File System(2017-01-01) Golpayegani, Navid; Halem, Milton; Computer Science and Electrical Engineering; Computer ScienceA data center today is responsible for safely managing big data volumes and balancing the complex needs between data producers and consumers. This balance often involves reconciling the needs of easy access and rapid retrieval in ways desired by the consumers with the needs of long term availability, reliability, and expandability of data producers. The long term continuous support of data storage adds another layer of complexity for the file system. As storage architecture and big data volumes evolve, existing file system's primary focus is performance while less attention is payed to addressing the problems of the above long term servicing needs of their clients. I have developed the Lightweight Virtual File System (LVFS) to address these prob- lems through the unique conceptual approach of separating the most common tasks in- volved in a file system; namely storing data, locating data, and organizing data. Standard file systems are developed as single monolithic systems performing all three tasks. LVFS replaces these tasks with an architecture which enables the dynamic combination of dif- ferent algorithms for each of those tasks. Using this approach, LVFS is capable of con- structing a storage system, which allows for ready availability, reliability, expandability, and long term support while, simultaneously, assuring the performance of a stable system customizable to meet the needs of data consumers. After successful development and testing to allow for merging decades old storage ar- chitecture with new and incompatible ones, such as HGST Active Archive System, NASA Goddard Space Flight Center's Terrestrial Information Systems Laboratory adopted LVFS for their production environment to create a single, integrated storage system without any software modifications. UMBC's Center for Hybrid Multicore Productivity Research de- ployed an instance on the IBM iDataPlex ?BlueWave? cluster to utilize Seagate's Active Drive systems as a storage and on-disk compute platform. With LVFS we show we were able to perform MapReduce computation directly on the drive with comparable perfor- mance to Hadoop running on BlueWave. It also shows a significant reduction in data leav- ing the active drive during computation thereby significantly increasing throughput.