38,202 research outputs found
Incremental Data Migration for Multi-Database Systems
Nowadays, database systems are one of the most
popular and essential software programs in computer systems.
Many computers are installed a database system and users
maybe want to use these database systems as one system. The
multi-database system is one of the solutions to this request.
The multi-database system is a kind of the distributed database
system. It is a cluster of independent database systems. As the
distributed database system, the multi-database system has
some problems. One of these problems is data migration
among individual database systems in the multi-database
system. Many reorganization techniques for distributed
database systems already proposed. But these techniques are
not always adaptive to the data migration in the multidatabase
system. In order to overcome this problem, we adapt
the incremental scheme to the data migration in the multidatabase
system. In our new scheme, a large data migration
operation is divided into small ones, and other operations are
inserted between them. The experimental result proves the
improvement of the turn-around times of other operations
Synthesis of time-to-amplitude converter by mean coevolution with adaptive parameters
Copyright © 2011 the authors and Scientific Research Publishing Inc. This work is licensed under a Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/)The challenging task to synthesize automatically a time-to-amplitude converter, which unites by its functionality several digital circuits, has been successfully solved with the help of a novel methodology. The proposed approach is based on a paradigm according to which the substructures are regarded as additional mutation types and when ranged with other mutations form a new adaptive individual-level mutation technique. This mutation approach led to the discovery of an original coevolution strategy that is characterized by very low selection rates. Parallel island-model evolution has been running in a hybrid competitive-cooperative interaction throughout two incremental stages. The adaptive population size is applied for synchronization of the parallel evolutions
Towards a Holistic Integration of Spreadsheets with Databases: A Scalable Storage Engine for Presentational Data Management
Spreadsheet software is the tool of choice for interactive ad-hoc data
management, with adoption by billions of users. However, spreadsheets are not
scalable, unlike database systems. On the other hand, database systems, while
highly scalable, do not support interactivity as a first-class primitive. We
are developing DataSpread, to holistically integrate spreadsheets as a
front-end interface with databases as a back-end datastore, providing
scalability to spreadsheets, and interactivity to databases, an integration we
term presentational data management (PDM). In this paper, we make a first step
towards this vision: developing a storage engine for PDM, studying how to
flexibly represent spreadsheet data within a database and how to support and
maintain access by position. We first conduct an extensive survey of
spreadsheet use to motivate our functional requirements for a storage engine
for PDM. We develop a natural set of mechanisms for flexibly representing
spreadsheet data and demonstrate that identifying the optimal representation is
NP-Hard; however, we develop an efficient approach to identify the optimal
representation from an important and intuitive subclass of representations. We
extend our mechanisms with positional access mechanisms that don't suffer from
cascading update issues, leading to constant time access and modification
performance. We evaluate these representations on a workload of typical
spreadsheets and spreadsheet operations, providing up to 20% reduction in
storage, and up to 50% reduction in formula evaluation time
Vectorwise: Beyond Column Stores
textabstractThis paper tells the story of Vectorwise, a high-performance analytical database system, from multiple perspectives: its history from academic project to commercial product, the evolution of its technical
architecture, customer reactions to the product and its future research and development roadmap. One take-away from this story is that the novelty in Vectorwise is much more than just column-storage:
it boasts many query processing innovations in its vectorized execution model, and an adaptive mixed
row/column data storage model with indexing support tailored to analytical workloads. Another one is that there is a long road from research prototype to commercial product, though database research continues to achieve a strong innovative influence on product development
A Fast and Efficient Incremental Approach toward Dynamic Community Detection
Community detection is a discovery tool used by network scientists to analyze
the structure of real-world networks. It seeks to identify natural divisions
that may exist in the input networks that partition the vertices into coherent
modules (or communities). While this problem space is rich with efficient
algorithms and software, most of this literature caters to the static use-case
where the underlying network does not change. However, many emerging real-world
use-cases give rise to a need to incorporate dynamic graphs as inputs.
In this paper, we present a fast and efficient incremental approach toward
dynamic community detection. The key contribution is a generic technique called
, which examines the most recent batch of changes made to an
input graph and selects a subset of vertices to reevaluate for potential
community (re)assignment. This technique can be incorporated into any of the
community detection methods that use modularity as its objective function for
clustering. For demonstration purposes, we incorporated the technique into two
well-known community detection tools. Our experiments demonstrate that our new
incremental approach is able to generate performance speedups without
compromising on the output quality (despite its heuristic nature). For
instance, on a real-world network with 63M temporal edges (over 12 time steps),
our approach was able to complete in 1056 seconds, yielding a 3x speedup over a
baseline implementation. In addition to demonstrating the performance benefits,
we also show how to use our approach to delineate appropriate intervals of
temporal resolutions at which to analyze an input network
COBOL to Java and Newspapers Still Get Delivered
This paper is an experience report on migrating an American newspaper
company's business-critical IBM mainframe application to Linux servers by
automatically translating the application's source code from COBOL to Java and
converting the mainframe data store from VSAM KSDS files to an Oracle
relational database. The mainframe application had supported daily home
delivery of the newspaper since 1979. It was in need of modernization in order
to increase interoperability and enable future convergence with newer
enterprise systems as well as to reduce operating costs. Testing the modernized
application proved to be the most vexing area of work. This paper explains the
process that was employed to test functional equivalence between the legacy and
modernized applications, the main testing challenges, and lessons learned after
having operated and maintained the modernized application in production over
the last eight months. The goal of delivering a functionally equivalent system
was achieved, but problems remained to be solved related to new feature
development, business domain knowledge transfer, and recruiting new software
engineers to work on the modernized application.Comment: 4 pages, Accepted to be Published in: Proceedings of the 2018 IEEE
International Conference on Software Maintenance and Evolution (ICSME),
September 23-29, 2018, Madrid, Spai
Microservices Architecture Enables DevOps: an Experience Report on Migration to a Cloud-Native Architecture
This article reports on experiences and lessons learned during incremental migration and architectural refactoring of a commercial mobile back end as a service to microservices architecture. It explains how the researchers adopted DevOps and how this facilitated a smooth migration
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