• Journal of KIISE:Databases
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• v.29 no.6
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• pp.464-476
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• 2002

Main-memory database systems which reside entire databases in main memory are suitable for high-performance real-time transaction processing. If two-phase locking(2PL) as concurrency control protocol is used for the transactions accessing main-memory databases, however, the possibility of lock conflict will be low but lock operations become relatively big overhead in total transaction processing time. In this paper, We designed a real-time static locking(RT-SL) protocol which minimizes lock operation overhead and reflects the priority of transactions and we implemented it on a main-memory real-time database system, Mr.RT. We also evaluate and compare its performance with the existing real-time locking protocols based on 2PL such as 2PL-PI and 2PL-HP. The extensive experiments reveal that our RT-SL outperforms the existing ones in most cases.

• International Journal of Reliability and Applications
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• v.3 no.4
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• pp.155-164
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• 2002

This paper focuses on how modem data mining can be integrated with real-time relational databases and commercial data warehouses to improve reliability in real-time. An important Issue for many manufacturers is the development of relational databases that link key product attributes with real-time process parameters. Helpful data for key product attributes in manufacturing may be derived from destructive reliability testing. Destructive samples are taken at periodic time intervals during manufacturing, which might create a long time-gap between key product attributes and real-time process data. A case study is briefly summarized for the medium density fiberboard (MDF) industry. MDF is a wood composite that is used extensively by the home building and furniture manufacturing industries around the world. The cost of unacceptable MDF was as large as 5% to 10% of total manufacturing costs. Prevention can result In millions of US dollars saved by using better Information systems.

• Journal of the Korean Society for Railway
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• v.19 no.4
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• pp.445-455
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• 2016

A goal of the Real-time railway safety supervision system is to improve the safety oversight efficiency and to prevent accidents by integrating existing distributed monitoring systems, train, signal, power and facilities. So, the system require better performance regarding real-time processing based on big data. The disk-based database that is used in existing railway control systems has a problem with real-time processing; memory-based databases haves a limitation in terms of big-data processing; and time series databases haves a limitation in terms of real-time processing. So, we need a new database architecture for simultaneous real-time processing based on big data. In this study, we review the existing railway monitoring systems and propose a new database architecture for a real-time railway safety supervision system.

• Journal of KIISE:Software and Applications
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• v.26 no.10
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• pp.1167-1167
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• 1999

Although spatial databases support an efficient spatial management on objects in the real world, they have a characteristic that process only spatial information valid at current time, So in case of change in the spatial domain, it is very hard to support an efficient historical management for time-varying spatial information because they delete an old value and then replace with new value that is valid at current time. To solve these problems, there are rapidly increasing of interest for spatiotemporal databases, which serve historical functions for spatial information as well as spatial management functions for an object. However most of them presented in an abstract time-varying spatial phenomenon, but have not presented a concrete policy in spatiotemporal databases. In this paper, we propose a spatiotemporal data model that supports bitemporal time concepts in three dimensional architecture. In the proposed model, not only data types and their operation for object of spatiotemporal databases have been classified, but also mathematical expressions using formal semantics for them have been given. Then, the data structures and their operations based on relational database model as well as object-oriented database model are presented.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.142-144
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• 2001

응용 환경에서 동시에 이종의 모델을 지원하는 다수의 데이터베이스에 대하여 이들을 동시에 사용하거나 서로 간의 데이터 이전을 위해서는 스키마 변환과 질의 변환이 필요하다. 본 논문에서는 이종 모델 데이터베이스간의 상호 질의를 위해, 1) 관계형 스키마를 객체지향 스키마로 변환하고, 2) 관계 데이터베이스의 데이터를 객체 데이터베이스로 이전하며, 3)사용자의 관계형 질의를 객체 데이터베이스에서 인식할 수 있도록 변환하는 수행하는 중개자(Mediator)의 설계에 대해 기술한다. 제안된 중개자는 관계형 SQL 질의를 받아서, 데이터의 위치에 다랄 적절한 질의로 변환한 후, 관계 데이터베이스와 객체 데이터베이스에 있는 데이터를 자동으로 처리한다. 결과적으로, 중개자는 서로 다른 데이터베이스를 동시에 사용할 수 있는 기초가 될 것이다.

• Journal of Information Processing Systems
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• v.6 no.2
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• pp.163-176
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• 2010

Nowadays due to the rapid advances in the field of information systems, transactional databases are being updated regularly and/or periodically. The knowledge discovered from these databases has to be maintained, and an incremental updating technique needs to be developed for maintaining the discovered association rules from these databases. The concept of Temporal Association Rules has been introduced to solve the problem of handling time series by including time expressions into association rules. In this paper we introduce a novel algorithm for Incremental Mining of General Temporal Association Rules (IMTAR) using an extended TFP-tree. The main benefits introduced by our algorithm are that it offers significant advantages in terms of storage and running time and it can handle the problem of mining general temporal association rules in incremental databases by building TFP-trees incrementally. It can be utilized and applied to real life application domains. We demonstrate our algorithm and its advantages in this paper.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.2
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• pp.356-363
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• 2002

Transactions in real-time active databases have the notion of activeness where transactions are generated by external effects and another transaction. In this paper, we improve the real -time active concurrency control algorithm by applying Thomas' write rule and considering relationship between transactions fired by active rules. We also present the experimental results of our algorithm comparing other real-time active concurrency control algorithms. The experimental results show that our algorithm has superior performance with respect to the raio of transactions satisfying deadline.

• Journal of Industrial Technology
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• v.20 no.B
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• pp.219-226
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• 2000

In this paper, we propose a new novel method for similarity search that supports time warping. Our primary goal is to innovate on search performance in large databases without false dismissal. To attain this goal, we devise a new distance function $D_{tw-lb}$ that consistently underestimates the time warping distance and also satisfies the triangular inequality. $D_{tw-lb}$ uses a 4-tuple feature vector extracted from each sequence and is invariant to time warping. For efficient processing, we employ a multidimensional index that uses the 4-tuple feature vector as indexing attributes and $D_{tw-lb}$ as a distance function. We prove that our method does not incur false dismissal. To verify the superiority of our method, we perform extensive experiments. The results reveal that our method achieves significant speedup up to 43 times with real-world S&P 500 stock data.

• Journal of Wetlands Research
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• v.14 no.3
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• pp.385-397
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• 2012

A grid based physically distributed model analyzes rainfall-runoff using physical parameters and grid-typed spatial and hydrological data. This study have developed a real time runoff modelling system using GRM RT(Grid based Rainfall-runoff Model Real Time) which is a real time flow analysis module in GRM, a grid based physically distributed rainfall-runoff model. Weather radar data received in real time are calibrated by using real time AWS from Korea Meteorological Administration(KMA), and they are applied to real time runoff modeling. And the runoff model is calibrated by using observed discharges from a water level gauge in real time. This study have designed and implemented the databases necessary to construct the real time runoff modelling system, and established the process of a real time runoff modelling. And the performances of the developed system have been evaluated. The system have been applied to Nerinheon watershed located in the upstream of Soyanggang Dam and the application results are evaluated.

• Genomics & Informatics
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• v.2 no.3
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• pp.142-146
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• 2004

Biological data and analysis tools are accumulated in distributed databases and web servers. For this reason, biologists who want to find information from the web should be aware of the various kinds of resources where it is located and how it is retrieved. Integrating the data from heterogeneous biological resources will enable biologists to discover new knowledge across the specific domain boundaries from sequences to expression, structure, and pathway. And inevitably biological databases contain noisy data. Therefore, consensus among databases will confirm the reliability of its contents. We have developed WeSAT that integrates distributed and heterogeneous biological databases and analysis tools, providing through Web Services protocols. In WeSAT, biologists are retrieved specific entries in SWISS-PROT/EMBL, PDB, and KEGG, which have annotated information about sequence, structure, and pathway. And further analysis is carried by integrated services for example homology search and multiple alignments. WeSAT makes it possible to retrieve real time updated data and analysis from the scattered databases in a single platform through Web Services.