An orbital service model allows data to be collected, stored and used on different nodes comprising an ad-hoc system where provider craft supply services to consumer craft. Ad-hoc networks and provider-consumer relati...
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ISBN:
(纸本)9781628410112
An orbital service model allows data to be collected, stored and used on different nodes comprising an ad-hoc system where provider craft supply services to consumer craft. Ad-hoc networks and provider-consumer relationships are commonly used in various applications on Earth. The deterministic movement of spacecraft, however, allows the ad-hoc network and service providing model to operate in a different way than would be typical in most terrestrial ad-hoc networks. While long periods of no direct node-to-node connectivity may exist, the periods of connectivity are pre-known based on orbital parameters. Additionally, paths for indirect connectivity can be identified and evaluated for cost effectiveness. This paper presents a data management approach for an orbital computing ad-hoc system. Algorithms for determining where data should be stored (identification of most useful point of storage, whether multiple copies are justified) and how movement should be affected (transfer scheduling, replication, etc.) are presented and evaluated.
This paper will examine the underlying features of the distributed database architecture .Learning the task of distributed database management system will lead us to a successful design. The design will improve scalab...
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ISBN:
(纸本)9781424437566
This paper will examine the underlying features of the distributed database architecture .Learning the task of distributed database management system will lead us to a successful design. The design will improve scalability, accessibility and flexibility while accessing various types of data. Developing a successful distributed database system requires to address the importance of security issues that may arise and possibly compromise the access control and the integrity of the system. We propose some solutions for some security aspects such as multilevel access control, confidentiality, reliability, integrity and recovery that pertain to a distributed database system.
Due to covert channel problem, traditional concurrency control protocols cannot be used in multilevel secure database system. Concurrency control protocol for multilevel secure database should ensure that transactions...
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ISBN:
(纸本)0769530508
Due to covert channel problem, traditional concurrency control protocols cannot be used in multilevel secure database system. Concurrency control protocol for multilevel secure database should ensure that transactions at lower security level are never delayed by higher security level transactions in the event of a data conflict. This may lead to the abortion or re-execution of high security level transactions over and over again making the secure concurrency control protocol unfair towards high security level transactions. In this paper we propose a feedback based secure concurrency control protocol for multilevel secure distributed databases, which ensure fairness property for transactions at different security level. Through a detailed simulation study we examine the fairness and performance of our feedback based secure concurrency control for a variety of workloads.
The problem of traditional distributed database implementation in real-time control is discussed. According to features of data in real-time control distributed system, a enhanced performance design model (EPADM) of d...
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distributed databases are fundamental infrastructures of today's large-scale software systems such as cloud systems. Detecting anomalies in distributed databases is essential for maintaining software availability....
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ISBN:
(纸本)9798400704901
distributed databases are fundamental infrastructures of today's large-scale software systems such as cloud systems. Detecting anomalies in distributed databases is essential for maintaining software availability. Existing approaches, predominantly developed using Loghub-a comprehensive collection of log datasets from various systems-lack datasets specifically tailored to distributed databases, which exhibit unique anomalies. Additionally, there's a notable absence of datasets encompassing multi-anomaly, multinode logs. Consequently, models built upon these datasets, primarily designed for standalone systems, are inadequate for distributed databases, and the prevalent method of deeming an entire cluster anomalous based on irregularities in a single node leads to a high false-positive rate. This paper addresses the unique anomalies and multivariate nature of logs in distributed databases. We expose the first open-sourced, comprehensive dataset with multivariate logs from distributed databases. Utilizing this dataset, we conduct an extensive study to identify multiple database anomalies and to assess the effectiveness of state-of-the-art anomaly detection using multivariate log data. Our findings reveal that relying solely on logs from a single node is insufficient for accurate anomaly detection on distributed database. Leveraging these insights, we propose MultiLog, an innovative multivariate log-based anomaly detection approach tailored for distributed databases. Our experiments, based on this novel dataset, demonstrate MultiLog's superiority, outperforming existing state-of-the-art methods by approximately 12%.
Technological revolutions have greatly increased the use of IoT devices for our daily life. Driving the fact that everything surrounding us is getting connected what turns into an unstoppable increase in the amount of...
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ISBN:
(纸本)9781728110165
Technological revolutions have greatly increased the use of IoT devices for our daily life. Driving the fact that everything surrounding us is getting connected what turns into an unstoppable increase in the amount of data produced. This data represents the state of diverse environmental events and helps to control a large set of distinct activities. So, accurate and secure management of this data is essential for any computing platform. Moreover, in order to provide real-time services in a distributed system (i.e., smart city), the data should be properly and securely managed. It is well known that shifting these tasks to the edge (i.e., near to the end users), highly facilitates these two objectives. The recently proposed Fog-to-Cloud (F2C) model is intended to enable data processing near to the edge, which helps to get better latency-sensitive services. However, some challenges remain to accurately and securely manage this data over the system, mainly due to the distributed F2C nature. Thus, considering these facts and challenges, in this paper we propose an architectural solution aimed at building a secure distributed database for F2C systems. Then, considering a real-case scenario, we perform some tests to measure the performance of our proposing schema. Finally, by comparing the performance between traditional cloud, fog/edge based execution model and our proposing SFDDM, we validate the effectiveness of our proposing schema.
Multilevel security requirements introduce a new dimension to traditional database schedulers as they cause covert channels. To prevent covert channels, scheduler for multilevel secure database should ensure that tran...
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ISBN:
(纸本)9781424429271
Multilevel security requirements introduce a new dimension to traditional database schedulers as they cause covert channels. To prevent covert channels, scheduler for multilevel secure database should ensure that transactions at low security level are never delayed by high security level transactions in the event of a data conflict. This may subjected to an indefinite delay if it is forced to abort repeatedly to high security level transactions and making the secure scheduler unfair towards high security level transactions [12]. This paper proposes secure database scheduler that is based on both optimistic and locking techniques (SO2PL) for multilevel secure distributed database systems. The proposed database scheduler is free from covert channels without starving the high security level transactions. Through a simulation study we evaluate the performance of the SO2PL and compare it with S2PL scheduler.
In recent years, with the progress of IoT, the entry data from various sensors is accumulated on the cloud server and used for various analyses as big data. On the other hand, in order to transfer a large amount of da...
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ISBN:
(纸本)9781538621950
In recent years, with the progress of IoT, the entry data from various sensors is accumulated on the cloud server and used for various analyses as big data. On the other hand, in order to transfer a large amount of data to the cloud server, there were the problems such as the restriction of network bandwidth, and the delay of feedback control of the sensors. For these problems, Fog computing has been proposed in which the primary processing of the sensor data is performed at the fog node installed near the sensors, and only its processing results are transferred to the cloud server. However, in this method, in the case where the original data of the sensor is required for various analyses at the cloud server, such a data must be transferred additionally. That is, a mechanism is necessary to manage the data of the entire system and to mutually utilize it. In this paper, I propose a data model which consists of three levels: the first level saves the original sensor data and is placed in the fog node;the second level saves the extraction data extracted by the primary processing;the third level saves the analysis results data. The second and third levels are placed in the cloud server. And, by constructing this data model with a distributed database, it can be performed efficiently to refer the arbitrary original sensor data in the fog nodes from the cloud server. Moreover, I implement this reference processing in two ways using MongoDB, which is a kind of NoSQL database, to evaluate this data model. And, I show it is necessary to select the reference way according to the system environment: the network bandwidth, the database performance of the fog node and cloud server, and the number of the fog nodes.
With the database becoming ever-larger, the architecture is developing continually in order that the data and resource can be shared. There are many problems exiting in distributed database Based on C/S. After analyzi...
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ISBN:
(纸本)9812565329
With the database becoming ever-larger, the architecture is developing continually in order that the data and resource can be shared. There are many problems exiting in distributed database Based on C/S. After analyzing the advantage and disadvantage of single-tiered, double-tiered and three-tiered architecture, this paper proposes a solution of multi-tiered architecture. Finally, this paper gives an example of the multi-tiered architecture to demonstrate the advantage of it.
In the last years, remarkable improvements have been made in the ability of distributed database systems performance. A distributed database is composed of some sites which are connected to each other through network ...
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ISBN:
(纸本)9781509047086
In the last years, remarkable improvements have been made in the ability of distributed database systems performance. A distributed database is composed of some sites which are connected to each other through network connections. In this system, if good harmonization isn't made between different transactions, it may result in database incoherence. Nowadays, because of the complexity of many sites and their connection methods, it is difficult to extend different models in distributed database serially. The principle goal of concurrency control in distributed database is to ensure not interfering in accessibility of common database by different sites. Different concurrency control algorithms have been suggested to use in distributed database systems. In this paper, some available methods have been introduced and compared for concurrency control in distributed database.
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