• International conference on construction engineering and project management
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• 2009.05a
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• pp.856-863
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• 2009

The problem of urban decay in Hong Kong has drawn much attention of both practitioners and academics. Poorly managed buildings not just give a negative image to the Pearl of the Orient in the region, but also pose potential risk hazards to the health and safety of the general public. While it is necessary to devise a comprehensive plan on redevelopment and urban planning, preserving the existing buildings to maintain their conditions for habitation can be a short-term option to safeguard quality standard. With the increasing number of ageing buildings in Hong Kong, a lot of research efforts have been devoted to managing repair and maintenance projects properly (for example those initiated and funded by the Construction Industry Institute, Hong Kong; and the current study financially supported by The Hong Kong Polytechnic University). Given the short duration and more diversified nature of work, building repair and maintenance works are found to be more difficult to monitor and regulate when compared with new works. This paper aims to provide a comprehensive analysis on the problems of running building maintenance projects. An extensive review of contemporary literature was firstly conducted, which forms a solid basis for developing an empirical study on the problems and difficulties of running building maintenance projects from the viewpoints of industrial practitioners with a view to formulating effective strategies for managing maintenance projects successfully.

• Journal of KIISE:Databases
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• v.29 no.6
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• pp.492-501
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• 2002

An asynchronous trigger processor (ATP) is a oftware system that processes triggers after update transactions to databases are complete. In an ATP, discrimination networks are used to check the trigger conditions efficiently. Discrimination networks store their internal states in memory nodes. TriggerMan is an ATP and uses Gator network as the .discrimination network. The changes in databases are delivered to TriggerMan in the form of tokens. Processing tokens against a Gator network updates the memory nodes of the network and checks the condition of a trigger for which the network is built. Parallel token processing is one of the methods that can improve the system performance. However, uncontrolled parallel processing breaks trigger processing semantic consistency. In this paper, we propose four trigger processing consistency levels that allow parallel token processing with minimal anomalies. For each consistency level, a parallel token processing technique is developed. The techniques are proven to be valid and are also applicable to materialized view maintenance.

• Journal of Sasang Constitutional Medicine
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• v.12 no.2
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• pp.1-7
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• 2000

Greeting the 100 year celebration of the death of Master Dong-mu, through investigating his thoght on Scholarship and Philosophy, and his new view of human being based on Sasang, I tried to reevaluate him as a Confucianist of practical mind. The conclusions were as followings ; 1. Dong-mu's recognition system of things is that based on the mind of summarizing things in view of Affair-Mind-Body-Object originated from Confucianism, and It developed 'the Marvel of Easiness & simpleness based on Yin-yang' into 'the Marvel of Easiness & simpleness based on Sasang' 2 Through understanding old Confucianism newly, Dong-mu summarized human being as having a natural character in view of Nature and Order and an autonomical character in view of Knowledge and Deed, and emphasized an autonomical character in view of Knowledge and Deed 3. In view of Knowledge and Deed, Dong-mu presented How to Say and Behave, and took it as a model of behavior in the new Confucianism. Also he presented the view of Knowledge and Deed based on Constitutions, and took it as a new mind of treatment. 4. Dong-mu can be estimated highly, in that he completed a new confucian view-point of Human being in the period of philosophic chaos, and executed the mind of General health maintenance and the mind of control others through a confucian self-control.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.39
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• pp.89-98
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• 1996

This paper is concerned with cost analysis model in free -replacement policy under the periodic maintenance policy The free-replacement policy with minimal repairable item is considered as follows; in a manufacturer's view point operating unit is periodically replaced, if a failure occurs between minimal repair and periodic maintenance time, unit is remained in a failure condition. Also unit undergoes minimal repair at failures in minimal-repair interval. Then total expected cost per unit time is calculated according to maintenance period Tin a viewpoint of consumer's. The expected costs are included repair cost and usage cost: operating, fixed, minimal repair and loss cost. Numerical example is shown in which failure time of item has beta distribution.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1864-1870
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• 2007

The inspection periods for the metro EMU maintenances vary variously according to the countries and railway operators. And the inspection systems vary according to the safety, economical, technical aspects, and also the social environments like passengers and maintenance qualities, etc. Also, in economic point of view, maintenance requires the man power, facilities, equipments, purchasing of parts and the loss of not being in revenue service during the maintenance period. Recently, there is a tendency that the inspection periods are extended gradually owing to the increased reliabilities of the equipments and parts of EMUs. Even if it is the EMUs that are already be in service, once the inspection method is innovated, the inspection time can be reduced. The inspection management innovation scheme includes such methods as the complete module to module replacement when trouble shooting a faulty parts before putting the EMU back to revenue service, the replacements of parts in complete set unit for the heavy maintenance, the establishments of exchange periods for the wasting parts, modernization of inspection equipments, introduction of RAMS for the reliability improvement and computerization of EMU maintenance management, etc. I think it is possible to optimize the inspection scopes and periods per parts and equipments by the introduction of RAMS.

• Journal of the Korean Data and Information Science Society
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• v.24 no.4
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• pp.773-781
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• 2013

Recently, an extended warranty of the system following the expiration of the basic warranty is becoming increasingly popular to the user. In this respect, we suggest a preventive maintenance model following the expiration of extended warranty with minimal repair warranty from the user's point of view in this paper. Under basic warranty and extended warranty, the failed system is minimally repaired by the manufacturer at no cost to the user. For the preventive maintenance model, we derive the expressions for the expected cycle length, the expected total cost and the expected cost rate per unit time. Also, we determine the optimal preventive maintenance period and the optimal preventive maintenance number by minimizing the expected cost rate per unit time. Finally, the numerical examples are presented to illustrate the purpose when the failure time of the system has a Weibull distribution.

• Korean Journal of Computational Design and Engineering
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• v.19 no.1
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• pp.61-67
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• 2014

This paper proposes a procedure enabling the extraction of view-dependent triangular approximations from a height map. In general, procedures to approximate a height map use tree hierarchies. These methods, however, have a limitation in terms of accuracy, because they depend on tree hierarchy than terrain features. To overcome the difficult, we apply the simplification method for triangular meshes to a height map. The proposed procedure maintains full decimation procedure to support multiresolution. The maintenance of decimation procedure results in creation of the groups (trees), each of which consists of vertices that can be merged into one vertex (root node). As the groups have tolerance which is determined by some tests, they support the generation of view-dependent arbitrary triangular meshes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.6
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• pp.1082-1087
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• 2006

This paper presents a gas turbine data acquisition and monitoring system using a LabVIEW programming. The developed real-time monitoring system entitled a C-Tune DAS Plays an important role to make an analysis of the real-time operation of the gas turbine under maintenance. the LabVIEW based software is divided into three parts according to their original functions; Data acquisition, Data analysis and display, and Data storage. The data acquisition part receives data from a PMS (Plant Management System) server and two cFPs (Compact-Field Point). To verify the validity of the developed system, it is applied to gas turbines in the combined cycle power plant in Korea.

• The KIPS Transactions:PartD
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• v.9D no.4
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• pp.561-570
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• 2002

In order to evaluate the performance of incremental update algorithms, we perform experimental tests on the time of updating view objects. In this paper, the incremental update algorithms are evaluated on two kinds of materialized methods : materialization by value-copy and materialization by preserving object identifiers (OIDs). The result of performance evaluation shows that there is little difference in the updating time of view objects between two materialization methods. The evaluation of query processing on spatial views shows that materialization by value-copy is much better than materialization by preserving OIDs. As the results of overall performance evaluation, it is more desirable to use the incremental update method based on materialization by value-copy than the incremental update method based on materialization by preserving OIDs.

• Journal of Energy Engineering
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• v.24 no.1
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• pp.10-16
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• 2015

Recently, RCM(reliability centered maintenance) process is introduced and applied for the planning and implementing efficient and effective maintenance system in terms of optimal rolling stock maintenance. Particularly, cost-time benefits analysis associated with the implementation of RCM for rolling stock maintenance is necessary and required for railway operator in advance. The RCM process was primarily starting from military, airplane and nuclear industries and is now adapted in railway industry for local railway operators. This paper focuses on suggesting the way of connecting the RCM process with railway maintenance activities in the railway operation field. Thus, in order to introduce and establish reliability activities, it needs to review and evaluate the maintenance environment in the organizational point of view. Based on these reviews and evaluations, various maintenance methodologies are reviewed for customizing local railway field situations and establish specific process in the application of major systems on the reliability technology. In this paper, the railway RCM process is proposed for the establishment and construction of the systematic and optimal maintenance system.