Jörg Ott, Jussi Kangasharju, Nitinder Mohan · 2025
Emerging Low Earth Orbit (LEO) satellite constellations have been considered for uses beyond plain Internet access, including content caching and edge computing. Assuming satellites are equipped with inter-satellite links, we propose using these links and thus the space in-between satellites, paired with a dedicated satellite queuing system, to "store" data and provide access by keeping data in constant flux around the globe. We describe the properties and explore the capabilities of such a system and discuss some potential uses.
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Satzger, Benjamin · Publication Server OPUS (University of Augsburg) · 2007
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Trumler, Wolfgang · 2007
Abstract. Due to the huge amount of integrated devices and sensors in everyday objects ubiquitous systems are in vicinity and will be deployed in large scales in the near future. We expect these system to be unreliable as nodes may crash or vanish from time to time. Therefore a reliable data store is needed to offer application developers a secure place to store the data of the services. The data store itself is subject to the same unreliable infrastructure thus it must expose self-healing capabilities to overcome data loss due to node failures. In this paper we propose a distributed self-healing data store for ubiquitous systems that guarantees the availability of the stored data even if there is a node failure every 36 seconds in a system consisting of 100 nodes. We also monitor the availability of the nodes to improve the way the data of the data store is distributed in the system. 1
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Pietzowski, Andreas · OPUS (Augsburg University) · 2007
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首藤一幸, Kazuyuki Shudo · Tokyo Tech Research Repository (Tokyo Institute of Technology) · 2011
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Cottrell, Jared D. (Jared Desjardins), 1975- · DSpace@MIT (Massachusetts Institute of Technology) · 1998
Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.
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Xin Wang, Jianhua Su · 2013
This paper analyzes the advantages and disadvantages of the traditional HDFS cluster architecture. An application framework designed for the small and medium-sized HDFS clusters is proposed in this paper to make up for incomplete HDFS application architecture, difficulties on deploying, inefficiency on I/O processing of small files. In addition, a caching mechanism is added to optimize the operation system on processing small files. Experiments show that this plan is feasible and the increased disk cache can significantly improve the efficiency of processing small files and optimize the system.
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Auer, Jonas · Fachbereich Informatik (University of Stuttgart) · 2017
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Rajesh Bharati, Vahida Attar · Smart innovation, systems and technologies · 2022
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Marti Fraiz, Jonathan, Queralt Calafat, Anna, Gasull Moreira, Daniel et al. · LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) · 2017
In the Big Data era, both the academic community and industry agree that a crucial point to obtain the maximum benefits from the explosive data growth is integrating information from different sources, and also combining methodologies to analyze and process it. For this reason, sharing data so that third parties can build new applications or services based on it is nowadays a trend. Although most data sharing initiatives are based on public data, the ability to reuse data generated by private companies is starting to gain importance as some of them (such as Google, Twitter, BBC or New York Times) are providing access to part of their data. However, current solutions for sharing data with third parties are not fully convenient to either or both data owners and data consumers. Therefore we present dataClay, a distributed data store designed to share data with external players in a secure and flexible way based on the concepts of identity and encapsulation. We also prove that dataClay is comparable in terms of performance with trendy NoSQL technologies while providing extra functionality, and resolves impedance mismatch issues based on the Object Oriented paradigm for data representation.
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Panescu, Adrian-Tudor · Figshare · 2016
This paper presents TAO, Facebook's solution for storing and efficiently serving its social graph. A data model, an API for querying this data model and the hardware infrastructure put in place for this are detailed, along with a real-world performance evaluation.<br>This presentation was part of the first Papers We Love meetup in Iasi, Romania, in January 2016.
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Adrian-Tudor Pãnescu · Figshare · 2016
This paper presents TAO, Facebook's solution for storing and efficiently serving its social graph. A data model, an API for querying this data model and the hardware infrastructure put in place for this are detailed, along with a real-world performance evaluation.<br>This presentation was part of the first Papers We Love meetup in Iasi, Romania, in January 2016.
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David Novák · Lecture notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering · 2015
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DaeYoub Kim · Journal of the Korea Institute of Information Security and Cryptology · 2015
ABSTRACT To seamlessly provide content through the Internet, it is gener ally considered to use distributed processing for content reque sts converged on original content providers like P2P, CDN, and ICN. That is, after other nodes temporally save content, they handl e content requests instead of original content providers. However, in this case, it may be possible that a content sender is dif ferent from the original provider of the content. In this case, users may be exposed to various risks. To solve such a problem, it is highly recommended to verify received contents before using the m, but it can cause network traffic increases as well as a seri ous service delay. This paper proposes an efficient content verific ation scheme for distributed networking/data store environments and analyzes its performance. Keywords: Futur Internet, NDN, Web Caching, Content Verification, MHT I.서 론 * 초기 인터넷의 주된 목적은 원격 호스트들 간의 안전한 연결을 제공하는 것이었기 때문에, 현재와 같 접수일(2015년 5월 30일), 게재확정일(2015년 6월 22일)*본 연구는 한국연구재단 연구과제(NRF-2013R1A1A 2008389) 지원으로 수행하였습니다.†주저자, daeyoub69@suwon.ac.kr‡교신저자, daeyoub69@suwon.ac.kr(Corresponding author)
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Stanisław Deniziak, Tomasz Michno, Adam Krechowicz · Annals of Computer Science and Information Systems · 2015
The multimedia databases are becoming more and more popular nowadays. One of their main problem is a huge data amount storage. Another problem with multimedia databases is querying. Traditional approaches, based on textual keywords are not sufficient. More advanced techniques, incorporating image content features, should be used. In this paper we propose new multimedia database structure with ability of Content Based Image Retrieval which is based on our previous work: Query by Shape method (QS). Query by Shape is a method which is based on decomposing an object into features. Each feature may consists of shape primitive, a color or a texture. In this paper we only use shape primitives. In order to achieve high scalability and workload control, we propose a modified Scalable Distributed Two-layer Data Structure, as a storage. The modification incorporates adding tree structure, comparing algorithm and returning a set of results to the client.
Cited by 8Open access
Thomas Risse · 2005
The introduction of Service Oriented Architectures enables the transition from integrated, centrally controlled systems to federated and dynamic configurable systems. Scalability and reliability are key requirements for such infrastructures. Due to the size and dynamic only decentralized and self-organizing systems are able to accomplish the previously mentioned requirements. In this paper we describe our approach to tackle the problem within the BRICKS project. Here we use a completely decentralized XML database to store several types of metadata. We will present the database architecture and the way it is used in the BRICKS architecture, exemplary for service discovery. Furthermore will we give an overview of current research activities and preliminary results.
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Kaiwen Zhang, Mohammad Sadoghi, Hans‐Arno Jacobsen · 2016
There has been a recent push in the database community towards supporting real-time analytical queries (OLAP) while sustaining a large volume of fine-grained updates (OLTP). Supporting these types of workloads require both an efficient data storage layer as well as a distributed architecture. In this demo, we address the latter point with our Distributed Lineage-based Data Store (DL-Store), which is a distributed data processing engine. DL-Store is built on top of L-Store, which is a lineage-based storage architecture designed to handle mixed OLTP and OLAP workloads, and provides scalability and elasticity by supporting multiple L-Store nodes. To maintain the desired consistency semantics, DL-Store employs a distributed transaction handler component which can horizontally scaled by provisioning additional transaction manager nodes. We leverage partitioning in the record space of the transactions to minimize communication across transaction managers while ensuring consistent execution. The demo shows our implementation of DL-Store over Apache Spark using a variety of use cases.
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G. P. Dubois-Felsmann, W Röthel, D. Kovalskyi et al. · CERN Document Server (European Organization for Nuclear Research) · 2005
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Cyril Grandjean · Radar (Oxford Brookes University) · 2012
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Peters, Nicholas · Scholarly Commons (Embry–Riddle Aeronautical University) · 2022
The task of achieving successful store separation from aircraft and spacecraft has historically been and continues to be, a critical issue for the aerospace industry. Whether it be from store-on-store wake interactions, store-parent body interactions or free stream turbulence, a failed case of store separation poses a serious risk to aircraft operators. Cases of failed store separation do not simply imply missing an intended target, but also bring the risk of collision with, and destruction of, the parent body vehicle. Given this risk, numerous well-tested procedures have been developed to help analyze store separation within the safe confines of wind tunnels. However, due to increased complexity in store separation configurations, such as rotorcraft and cavity-based separation, there is a growing desire to incorporate computational fluid dynamics (CFD) into the early stages of the store separation analysis. A viable method for achieving this objective is available through data-driven surrogate modeling of store distributed loads. This dissertation investigates the practicality of applying various data-driven modeling techniques to the field of store separation. These modeling methods will be applied to four demonstration scenarios: reduced order modeling of a moving store, design optimization, supersonic store separation, and rotorcraft store separation. For the first demonstration scenario, results are presented for three sub-tasks. In the first sub-task proper orthogonal decomposition (POD), dynamic mode decomposition (DMD), and convolutional neural networks (CNN) were compared for their capability to replicate distributed pressure loads of a pitching up prolate spheroid. Results indicated that POD was the most efficient approach for surrogate model generation. For the second sub-task, a POD-based surrogate model was derived from CFD simulations of an oscillating prolate spheroid subject to varying reduced frequency and amplitude of oscillation. The obtained surrogate model was shown to provide high-fidelity predictions for new combinations of reduced frequency and amplitude with a maximum percent error of integrated loads of less than 3\%. Therefore, it was demonstrated that the surrogate model was capable of predicting accurately at intermediate states. Further analysis showed a similar surrogate model could be generated to provide accurate store trajectory modeling under subsonic, transonic, and supersonic conditions. In the second demonstration scenario, a POD-based surrogate model is derived from a series of CFD simulations of isolated rotors in hover and forward flight. The derived surrogate models for hover and forward flight were shown to provide integrated load predictions within 1% of direct CFD simulation. Additionally, results indicated that computational expense could be reduced from 20 hours on 440 CPUs to less than a second on a single CPU. Given the reduction of cost and high fidelity of the surrogate model, the derived model was leveraged to optimize the twist and taper ratio of the rotor such that the efficiency of the rotor was maximized. For the third demonstration scenario, a POD and CNN surrogate model was derived for fixed-wing based supersonic store separation. Results demonstrated that both models were capable of providing high-fidelity predictions of the store's distributed loads and subsequent trajectory. For the final demonstration scenario, a POD-based surrogate model was derived for the case of a store launching from a rotorcraft. The surrogate model was derived from three CFD simulations while varying ejection force. This surrogate model was then validated against CFD simulation of a new store ejection force. Results indicated that while the surrogate model struggled to provide detailed predictions of store distributed loads, mean load variations could be modeled well at a massively reduced computational cost. For each rotorcraft store separation CFD simulation, the computational cost required 10 days of simulation time across 880. While using the surrogate model, comparable predictions could be produced in under a minute on a single core. Overall findings from this study indicate that massive CFD generated data-sets can be efficiently leveraged to create meaningful surrogate models capable of being deployed to highly iterative design tasks relevant to store separation. Through further improvements, similar surrogate models can be combined with a control strategy to achieve trajectory optimization and control.
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