Graph databases, similar to other nosql approaches, have emerged as an alternative to solve specific problems ill fitted to relational models. The huge amounts of data produced, and the high capability for horizontal ...
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ISBN:
(纸本)9781509050475
Graph databases, similar to other nosql approaches, have emerged as an alternative to solve specific problems ill fitted to relational models. The huge amounts of data produced, and the high capability for horizontal scalability provided by nosql databases has led to the increasing adoption of these systems, which can now be adapted to support geographic data. This article presents an analysis on the behavior of a graph oriented geographic databases compared to those designed with a relational model, using the database management systems PostgreSQL/PostGIS and Neo4j.
nosql database system is widely used in Big Data environment for its high performance and scalability. Due to the width of usage of nosql database, it is inevitable to store sensitive data in it. Utilizing homomorphic...
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nosql database system is widely used in Big Data environment for its high performance and scalability. Due to the width of usage of nosql database, it is inevitable to store sensitive data in it. Utilizing homomorphic encryption, sensitive data can be encrypted and calculated in the form of ciphertext to preserve privacy. Although calculating on homomorphically encrypted data is possible, searching on these data is not simple for the calculating results are encrypted and the search engine doesn't know what data should be sent back to the requester. A homomorphic searching scheme is proposed to handle this problem. In this scheme, the searching function is divided into two parts named homomorphic comparing and homomorphic decryption. The homomorphic comparing is executed by the encrypted data holder, and the homomorphic decryption is executed by the key holder. With this scheme, encrypted data holder can only get encrypted data and calculate the encrypted differences of these data, and the key holder can only get the encrypted differences and decrypt them. A sample implementation of the scheme with MongoDB is given. Analysis and experimental results show that the proposed scheme is secure and practical.
Emerging byte-addressable non-volatile memory is considered an alternative storage device for persistence guarantee with high performance. In this work, we design NVCL (NVRAM Cache-Line Granularity Logging) and develo...
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ISBN:
(纸本)9781538674048
Emerging byte-addressable non-volatile memory is considered an alternative storage device for persistence guarantee with high performance. In this work, we design NVCL (NVRAM Cache-Line Granularity Logging) and develop it in Redis. The proposed NVCL exploits the cache-line flush granularity of NVRAM to maintain the write-ahead differential log and is able to flush non-continuous dirty cache lines to guarantee persistence. NVCL effectively reduces the size of persistent logs by only flushing updated data in every memory page. We measured the performance on an Intel machine with a 16 GiB non-volatile dual in-line memory module (NVDIMM). Our performance study shows that NVCL can save up to 127× NVRAM writes and shows 84% speedup comparing to Redis append-only-file logging mechanism. NVCL also reduces up to 50% NVRAM writes and achieves 15% speedup over state-of-the-art logging mechanism NVWAL.
Distributed control strategies have been attracted significant attention due to numerous advantages over traditional centralized control strategies. The development of deep reinforcement learning method provides a nov...
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Distributed control strategies have been attracted significant attention due to numerous advantages over traditional centralized control strategies. The development of deep reinforcement learning method provides a novel approach to control grid without knowing the system's parameters. The training and validating process with grid simulation as environment have been supported by several toolboxes. In this paper, a platform based on redis nosql database is proposed to the deploy the multi-agent system of deep reinforcement learning algorithms for control microgrid in a distributed manner. The accuracy of agent implementation under realistic condition with physical communication network can be evaluated with the proposed platform. The distributed control in islanded DC microgrid using Deep Deterministic Policy Gradient is introduced as an use case to show the operation of the platform.
The advent of the so-called nosql databases has brought about a new model of using storage systems. While traditional relational database systems took advantage of features offered by centrally-managed, enterprise-cla...
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ISBN:
(纸本)9781450319003
The advent of the so-called nosql databases has brought about a new model of using storage systems. While traditional relational database systems took advantage of features offered by centrally-managed, enterprise-class storage arrays, the new generation of database systems with weaker data consistency models is content with using and manag- ing locally attached individual storage devices and providing data reliability and availability through high-level software features and protocols. This tutorial aims to review the architecture of selected nosql DBs to lay the foundations for understanding how these new DB systems behave. In particular, it focuses on how (in)efficiently these new systems use I/O and other resources to accomplish their work. The tutorial examines the behavior of several nosql DBs with an emphasis on Cassandra - a popular nosql DB system. It uses I/O traces and resource utilization profiles captured in private cloud deployments that use both dedicated directly attached storage as well as shared networked storage.
The paper work is mainly focussing on query optimization of database on cloud computing environment. We are also taking care of implementation of such cloud databases on public as well as private cloud system. During ...
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ISBN:
(纸本)9781728188768;9781728188775
The paper work is mainly focussing on query optimization of database on cloud computing environment. We are also taking care of implementation of such cloud databases on public as well as private cloud system. During the research of this topic, after going through various literatures available, we found that resource allocation on private cloud and public cloud is really a challenging one and also working on cloud databases for optimization on nosql databases through various cluster will be a new concepts of implementation and we wish to see their real-time results based on various operation.
The trajectory data often contains a large amount of information. So effective storage management is needed to analyze and apply the trajectory data. This paper proposes a distributed storage strategy for the characte...
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The trajectory data often contains a large amount of information. So effective storage management is needed to analyze and apply the trajectory data. This paper proposes a distributed storage strategy for the characteristics of trajectory data and the requirement of data balance among distributed nodes. A trajectory data is converted into a rectangle by the MBR to ensure data integrity;and the center of the MBR is calculated for K-Means clustering;then, this paper divides the clustering results by grid and merges the grids with high overlap rate. Finally, a data partitioning strategy is used to store the divided data in each nodes so that the data volume of each node is balance. Experiments show that the proposed distributed storage strategy can effectively take into account the integrity of trajectory data, spatial proximity, data structure flexibility to achieve data balance among each nodes based on distributed nosql database.
Large volumes of data present a significant challenge and can lead to high costs for organizations. As datasets grow, the operational efficiency of applications tends to decline, which can result in customer attrition...
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ISBN:
(数字)9798331504946
ISBN:
(纸本)9798331504953
Large volumes of data present a significant challenge and can lead to high costs for organizations. As datasets grow, the operational efficiency of applications tends to decline, which can result in customer attrition. Therefore, enhancing the performance of applications is crucial for capturing increasingly large amounts of customer data. Cloud computing services provide a practical solution to this performance issue by effectively managing both SQL and nosql databases. This paper outlines a case study aimed at identifying the most effective method for improving application performance with large and continuously expanding datasets. To achieve this, the query performance of SQL and nosql systems are compared. The comparison involves measuring the runtimes of queries executed on SQL and nosql databases hosted in the cloud, using the TPC benchmark. The experiment assesses the response times of both database types, ultimately indicating which method performs better.
Modern nosql databases use log-structured merge (LSM) storage architectures to support high write throughput. LSM architectures aggregate writes in a mutable MemTabte (stored in memory), which is regularly flushed to ...
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ISBN:
(数字)9781728108582
ISBN:
(纸本)9781728108599
Modern nosql databases use log-structured merge (LSM) storage architectures to support high write throughput. LSM architectures aggregate writes in a mutable MemTabte (stored in memory), which is regularly flushed to disk, creating a new immutable file called an SSTable. Periodically, some of the SSTables are chosen to be merged - replaced with a single SSTable containing their union. A merge policy (a.k.a. compaction policy) specifies when to do merges and which SSTables to combine. A bounded depth merge policy is one that guarantees that the number of SSTables never exceeds a given parameter k, typically in the range 3-10. Bounded-depth policies are useful in applications where low read latency is crucial, but they and their underlying combinatorics are not yet well understood. This paper compares several bounded-depth policies, including representative policies from industrial nosql databases and two new ones based on recent theoretical modeling. The results validate the proposed theoretical model and show that, compared to the existing policies, the newly proposed policies can have substantially lower write amplification.
Injection attacks remain yet one of the major challenges in non-relational data stores or nosql databases. Indeed, such databases are intended to store big data and are classified into four categories; Key-values Stor...
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Injection attacks remain yet one of the major challenges in non-relational data stores or nosql databases. Indeed, such databases are intended to store big data and are classified into four categories; Key-values Stores, Wide Column Stores, Document Stores, and Graph databases. The different vulnerabilities of these nosql databases have attracted many researchers to attempt solving or mitigating this problem. Unfortunately, extensive experiments have revealed that all proposed approaches and techniques are away from the expectations. This is due mainly to their focusing only either on some parts of the problem or on a specific nosql engine. In this paper, we propose an open tool architecture which can take into consideration any nosql engines belonging to the four data stores categories whatever the programming language used. The proposed tool architecture is able to detect first vulnerable statements in the static mode on the developer side. Second, it detects also automatically injection attacks during run-time on the server side thanks to the added instrumenting statements during the first control (static mode). The easy expansion and adaptation of the proposed tool to any nosql engine and/or any kind of attacks and/or programming languages makes it very attractive compared the existing ones. Indeed nowadays, we observe the emergence of new kinds of attacks once a new security approach or framework or technique is proposed.
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