After the starting of operation on December 1998, Subaru Telescope ARchive System (STARS) continued to store and manage the data taken at the summit of Mauna Kea, Hawaii, and total amount of data is currently about 3 ...
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ISBN:
(纸本)0819446238
After the starting of operation on December 1998, Subaru Telescope ARchive System (STARS) continued to store and manage the data taken at the summit of Mauna Kea, Hawaii, and total amount of data is currently about 3 TB in amount or similar to 600,000 files. The data production rate is increasing gradually with increasing stability of telescope and instrument operation. There were some upgrades in STARS itself after our report performed in the last SPIE meeting held in Munich on March 2000, and also were some new features developed and established in Mitaka, Japan for mirroring all data stored in STARS. We also started the releasing the data whicv passed the proprietary terms to world wide via seperate system. We will discuss about the concepts and current status of our distributed archive systems in detail, and its impact to scientific or enginieering return from Subaru telescope.
A demand-driven parallelization of the ray tracing algorithm is presented. Correctness and optimality of a perfect load balancing algorithm for image space subdivision are proved and its exact message complexity is gi...
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ISBN:
(纸本)3540440496
A demand-driven parallelization of the ray tracing algorithm is presented. Correctness and optimality of a perfect load balancing algorithm for image space subdivision are proved and its exact message complexity is given. An integration of antialiasing into the load balancing algorithm is proposed. A distributed object database allows rendering of complex scenes which cannot be stored in the memory of a single processor. Each processor maintains a permanent subset of the object database as well as a cache for a temporary storage of other objects. A use of object bounding boxes and bounding hierarchy in combination with the LRU (Last Recently Used) caching policy reduces the number of requests for missing data to a necessary minimum. The proposed parallelization is simple and robust. It should be easy to implement with any sequential ray tracer and any message-passing system. Our implementation is based on POV-Ray and PVM.
Using a distributed database system as a part of the distributed web sever architecture has obvious advantages. It is shown that a first phase distributed database system can be build by extending an existing object o...
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Using a distributed database system as a part of the distributed web sever architecture has obvious advantages. It is shown that a first phase distributed database system can be build by extending an existing object oriented database system with application-specific additions. A web database is implemented, as a part of the traditional HTTP-based distributed web server, using this distributed database system. (C) 1999 Elsevier Science B.V. All rights reserved.
distributed databases in general-purpose business software such as groupware widely use a method for simultaneously updating the replicas of other databases owned by each database according to the replication routing ...
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distributed databases in general-purpose business software such as groupware widely use a method for simultaneously updating the replicas of other databases owned by each database according to the replication routing schedule. In this paper, a replication routing schedule is discussed in which the time required for updating the replica is the minimum in the distributed database. Specifically, an optimization problem is first formulated for deriving the replication routing schedule with minimum update time. Next, in the cases of even and odd numbers of distributed databases, an algorithm providing a replication routing schedule as an optimum solution is presented in the even case, while a heuristic algorithm providing an approximate solution is shown for the odd case. These algorithms are extremely simple and are practical since the required amount of computational processing is small. (C) 1998 Scripta Technica, Electron Comm Jpn Pt 1, 82(2): 11-20, 1999.
Focusing on a distributed control service-control-node (SCP) that houses a database (DB) distributed across multiple modules, this paper proposes an autonomous distributed SCP architecture using multicasting access to...
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Focusing on a distributed control service-control-node (SCP) that houses a database (DB) distributed across multiple modules, this paper proposes an autonomous distributed SCP architecture using multicasting access to the distributed DB, and highlights its application areas. We assume as a basic condition that neither the network nor the other modules in the system are aware of the DB configuration. Based on this condition, we propose two basic methods: a unicast approach in which the DB management module that is selected at random by the network routes the DB access request to the module where the target data resides (Method A), and a multicast method in which DB access requests are broadcast to all modules (Method B). A quantitative evaluation is made of the number of required modules and required communications performance between modules which is determined by the capacity of the main memory and processing capacity of the processors. Based on the results, we conclude that Method B better exploits the advantages of module autonomous distribution technology within the limits that the economy of inter-module communication overhead is not impaired. Furthermore, in the event a module fails in Method B, a scheme is proposed in which the defective module is cut out of the multicast group, and multicasting continues. This could be implemented most effectively using a separate route under hardware control that is independent of the on-line communications route between modules.
In a lazy master replicated database, a transaction can commit after updating one replica copy (primary copy) at some master node. After the transaction commits, the updates are propagated towards the other replicas (...
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In a lazy master replicated database, a transaction can commit after updating one replica copy (primary copy) at some master node. After the transaction commits, the updates are propagated towards the other replicas (secondary copies), which are updated in separate refresh transactions. A central problem is the design of algorithms that maintain replica's consistency while at the same time minimizing the performance degradation due to the synchronization of refresh transactions. In this paper, we propose a simple and general refreshment algorithm that solves this problem and we prove its correctness. The principle of the algorithm is to let refresh transactions wait for a certain "deliver time" before being executed at a node having secondary copies. We then present two main optimizations to this algorithm. One is based on specific properties of the topology of replica distribution across nodes. In particular, we characterize the nodes for which the deliver time can be null. The other improves the refreshment algorithm by using an immediate update propagation strategy.
In this paper, we discuss our proposal of a distributed database system, DB-MAN (distributed database system based on database Migration in ATM Networks), which takes advantage of database migration in virtual local a...
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In distributed databases for general-purpose business software, such as groupware, the asynchronous replication update method is widely employed to assure coincidence in the contents of the database; the replications ...
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In this paper, a causal-phase ordering protocol is used as concurrency control mechanism to commit soft real-time distributed transactions. The protocol, called Causal-CC, consists of subdividing active transactions i...
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ISBN:
(纸本)1880843404
In this paper, a causal-phase ordering protocol is used as concurrency control mechanism to commit soft real-time distributed transactions. The protocol, called Causal-CC, consists of subdividing active transactions into distinct sets. Transactions into each set are virtually serialized and distributed over the servers composing the distributed system. Causal phases are then created according to the possible conflicts between transactions. These transactions are scheduled so as transactions of two successive phases are ensured to commit in a causal partial order. Causal-CC permits to reduce the execution time and to reduce the number of conflicts, allowing then more transactions to meet their deadlines.
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