• The KIPS Transactions:PartD
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• v.10D no.6
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• pp.917-926
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• 2003

More views in data warehouse, can respond to the users more rapidly because the user's requests may be processed by utilizing only the materialized views with higher probabilities rather than accessing base relations. But, more views cause longer update duration of all the materialized views. During the update time, queries of users can not be processed because accesses to the datawarehouse are blocked. Thus, the update durations of the materialized views are necessary to be reduced. In this paper, we propose algorithm the update duration of the materialized views owing to managing by distinguishing insecton/deletion operations. Though there might overheads for distinguishing insertion/deletion, we concluded that the proposed algorithm could be excellent than others.

• Asia pacific journal of information systems
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• v.13 no.4
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• pp.191-206
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• 2003

More views in data warehouse, can respond to the users more rapidly because the user's requests might be processed by accessing only the materialized views with higher probabilities rather than accessing base relations. But, the update duration for maintaining materialized views limits the number of materialized views in data warehouse. In this paper, we propose the algorithm for reducing update duration of materialized views, of which aggregation functions are maintained by self-maintenance. We also implement the proposed algorithm and evaluate the performance of the algorithm.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.1
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• pp.1-9
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• 2017

This paper proposes to improve the performance of a strap down inertial navigation system using a foot-mounted low-cost inertial measurement unit/magnetometer by configuring an attitude and heading reference system. To track position accurately and for attitude estimations, considering different dynamic constraints, magnetic measurement and a zero velocity update technique is used. A conventional strap down method based on integrating angular rate to determine attitude will inevitably induce long-term drift, while magnetometers are subject to short-term orientation errors. To eliminate this accumulative error, and thus, use the navigation system for a long-duration mission, a hybrid configuration by integrating a miniature micro electromechanical system (MEMS)-based attitude and heading detector with the conventional navigation system is proposed in this paper. The attitude and heading detector is composed of three-axis MEMS accelerometers and three-axis MEMS magnetometers. With an absolute algorithm based on gravity and Earth's magnetic field, rather than an integral algorithm, the attitude detector can obtain an absolute attitude and heading estimation without drift errors, so it can be used to adjust the attitude and orientation of the strap down system. Finally, we verify (by both formula analysis and from test results) that the accumulative errors are effectively eliminated via this hybrid scheme.

• Journal of KIISE:Databases
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• v.32 no.1
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• pp.100-110
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• 2005

The update transactions to be executed in spatial databases usually have been known as interactive and long duration works. To improve the parallelism of concurrent updates, it needs multiple transactions concurrently update a large spatial object which has a spatial extensions larger than workspace of a client. However, under the existing locking protocols, it is not possible to concurrently update a large spatial object because of conflict of a write lock This paper proposes a partial locking scheme of enabling a transaction to set locks on parts of a big object. The partial locking scheme which is an exclusive locking scheme set by user, acquires locks for a part of the big object to restrict the unit of concurrency control to a partial object of a big object. The scheme gives benefits of improving the concurrency of un updating job for a large object because it makes the lock control granularity finer.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.2210-2214
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• 2009

This paper summarizes progress on work under the Asian Pacific FRIEND(Flow Regimes from International Experimental and Network Data - APFRIEND) initiative of the International Hydrological Programme (IHP) of the United Nations Educational, Scientific and Cultural Organisation (UNESCO) from 2005 to 2009. The results of initial work on Rainfall Intensity Duration Frequency (IFD) have just been published as a volume by UNESCO. The results of work to date is concisely presented and observations made about lessons learnt on how to successfully integrate work from nine diverse countries with differing approaches to both hydrology and water resource management structures and on some possible directions for future work.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2000.11a
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• pp.369-374
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• 2000

Despite their tilde application of some traditional project management techniques like the Program Evaluation and Review Technique, they lack of learning, one of important factors in many disciplines today due to a static view far prefect progression. This study proposes a framework for estimation by learning based on a Linear Bayesian approach. As a project progresses, we sequentially observe the durations of completed activities. By reflecting this newly available information to update the distribution of remaining activity durations and thus project duration, we can implement a decision support system that updates e.g. the expected project completion time as well as the probabilities of completing the project within talc due date and by a certain date. By Implementing such customized systems, project manager can be aware of changing project status more effectively and better revise resource allocation plans.

• Journal of Intelligence and Information Systems
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• v.6 no.2
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• pp.91-98
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• 2000

Despite their wide application of some traditional project management techniques like the Program Evaluation and Review Technique, they lack of learning, one of important factors in many disciplines today, due to a static view for project progression. This study proposes a framework for estimation by loaming based on a Linear Bayesian approach. As a project Progresses, we sequentially observe the durations of completed activities. By reflecting this newly available information to update the distribution of remaining activity durations and thus project duration, we can implement a decision support system that updates e.g., the expected project completion time as well as the probabilities of completing the project within the due bate and by a certain date. By implementing such customized system, project manager can be aware of changing project status more effectively and better revise resource allocation plans.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.195-200
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• 2012

We present a new algorithm which can improve the tracking performance of the double-talk robust algorithm. A detection method of the echo path change and a modification method for the update equation of the conventional adaptive filter are proposed. A duration of the high error signal to scale parameter ratio varies according to the call status and this property is used to detect the echo path change. The proposed update equation of the adaptive filter improves the tracking performance by prohibiting wrong selection of the error signal. Simulations using real speech signals and echo paths of the ITU-T G.168 standard confirmed that as compared to the conventional algorithm, the proposed algorithm improved the tracking performance by more than 4 dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.8
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• pp.1336-1345
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• 2002

Materialized views in data warehouse play important roles in rapidly answering to users's requests for information Processing. More views in data warehouse, can respond to the users more rapidly because the user's requests may be processed by using only the materialized views with higher probabilities rather than accessing base relations. The limited duration, during which the materialized views are updated due to base relations's changes, limits the number of materialized views in data warehouse. In this paper, we propose efficient policy for updating the materialized views, which can save the update duration of views although MIN/MAX values frequently change in base relation. The policy updates the materialized views by distinguishing whether MIN/MAX values's changes in the base relation are insert value or delete value. Then, the number of accesses to the base relation is descreased when updating the MIN/MAX values in the materialized views.

• Journal of Communications and Networks
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• v.10 no.1
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• pp.38-43
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• 2008

In this paper, adaptive channel borrowing approach fuzzy neural networks for load balancing (ACB-FNN) is presented to maximized the number of served calls and the depending on asymmetries traffic load problem. In a wireless network, the call's arrival rate, the call duration and the communication overhead between the base station and the mobile switch center are vague and uncertain. A new load balancing algorithm with cell involved negotiation is also presented in this paper. The ACB-FNN exhibits better learning abilities, optimization abilities, robustness, and fault-tolerant capability thus yielding better performance compared with other algorithms. It aims to efficiently satisfy their diverse quality-of-service (QoS) requirements. The results show that our algorithm has lower blocking rate, lower dropping rate, less update overhead, and shorter channel acquisition delay than previous methods.