• The Transactions of the Korea Information Processing Society
• /
• v.6 no.11
• /
• pp.2875-2888
• /
• 1999

In this paper we present compiler-based active rule system to efficiently maintain spatial integrity constraints in a heterogeneous, distributed environment. Specially, the prototype active rule system presented has been developed as a component of a whole middleware system called SDBC(Spatile DataBase Connectivity). Due to this reason, our active rule system is provided for heterogeneous ODBMSs in a distributed environment and used to define spatial integrity constraints using the active rules in E-C-A(Event-Condition-Action) type. Using this active rule system, an application programmer can free himself from a heavier burden on the integrity maintenance of application objects. In the compiler-based approach, active rules applicable to events raised by a database program are directly inserted into the program in a function type by the preprocessor, and then they are compiled with the application program source codes. One advantage of this approach is that there is no run-time overhead accompanied by monitoring all the database transitions when preprocessed program is executed. This active rule system also provides facilities to manage changed rules and dynamically interpret those rules at run-tuime.

• Journal of Intelligence and Information Systems
• /
• v.12 no.3
• /
• pp.95-110
• /
• 2006

To enhance the rule-based reasoning capability of Semantic Web, the XRML (eXtensible Rule Markup Language) approach embraces the meta-information necessary for the extraction of explicit rules from Web pages and its maintenance. To effectuate the automatic identification of rules from unstructured texts, this research develops a framework of using rule ontology. The ontology can be acquired from a similar site first, and then can be used for multiple sites in the same domain. The procedure of ontology-based rule identification is regarded as a graph search problem with incomplete nodes, and an A* algorithm is devised to solve the problem. The procedure is demonstrated with the domain of shipping rates and return policy comparison portal, which needs rule based reasoning capability to answer the customer's inquiries. An example ontology is created from Amazon.com, and is applied to the many online retailers in the same domain. The experimental result shows a high performance of this approach.

• Proceedings of the KSR Conference
• /
• 1999.05a
• /
• pp.390-397
• /
• 1999

This paper investigates about the prediction of rail bending fatigue lifes for the purpose of the effective maintenance of surface irregularities of rail welded parts. The rail bending stresses are calculated using a track dynamic analysis program. The rail surface irregularities measured in situ are given as inputs in the analyses. On the other hand, the S-N curves are derived based on the results of bending fatigue tests. Using data found so far, rail fatigue lifes are estimated adopting a modified Miner's rule. The useful guides for maintenance of rail welded part are proposed in terms of grinding period and grinding depth of rail surface irregularities.

• International Journal of Reliability and Applications
• /
• v.4 no.1
• /
• pp.13-26
• /
• 2003

This paper presents a comparative study of a few commonly used maintenance scheduling methods for small utilities that consists solely of thermal generating plants. Two deterministic methods and a stochastic method are examined. The deterministic methods employ the leveling of reserve capacity criterion, of which one uses a heuristic rule to level the deterministic equivalent load obtained by using the product of the unit capacity and its corresponding forced outage rate. The stochastic method simulates the leveling of risk criterion by using the peak load carry capacity of available units. The results indicate that for the size and type of the maintenance scheduling problem described In this study, the stochastic method does not produce a schedule which is significantly better than the deterministic methods.

• Nuclear Engineering and Technology
• /
• v.56 no.10
• /
• pp.4327-4334
• /
• 2024

Preventive Maintenance(PM) for safety component during power operation at nuclear power plants, On-Line Maintenance(OLM) refers to intentionally entering the Limited Condition of Operation(LCO) specified in the Technical Specification(TS) for safety-related systems and components in order to perform preventive maintenance within the Allowed Outage Time (AOT). This study assessed the feasibility of conducting OLM at the domestic APR1400 nuclear power plant. It focused on preventive maintenance duration and risk perspectives. A total of 78 FEGs were developed for 4450 facilities, considering system functions and preventive maintenance scope during output operation for eight safety-related systems. Additionally, maintenance items included in FEGs were selected, designated as targets for OLM, and their maintenance durations were evaluated and compared with AOT for each maintenance item. As a result, the Auxiliary Feedwater and Essential Chilled Water systems were identified as systems allowing OLM. Furthermore, utilizing the Risk Monitoring System (RIMS), the increased risk value due to the unavailability of target equipment during preventive maintenance was analyzed to determine whether it falls within the acceptable range. Regarding the temporary risk increase caused by OLM, it was observed that in all systems, it falls within Zone III according to NUMARC93-01 standards, allowing for normal equipment arrangement for OLM. However, according to the risk increase standards rate in domestic nuclear power plants, when maintaining the A-train in four systems including Component Cooling Water, they are all evaluated as 'Orange,' indicating that measures for risk mitigation are necessary for OLM to be feasible. When considering extending AOT up to 1.6 times the maintenance time, the risk increase falls within Zone III according to permissible change in risk standards, indicating that AOT extension might be feasible based solely on risk changes. To apply OLM within the permissible risk management scope in domestic nuclear power plants, regulatory policies need to allow voluntary LCO entry for preventive maintenance, necessitating clear determination by regulatory agencies using risk-informed policies. While OLM seems viable concerning maintenance duration and quantitative risk aspects, for inducing regulatory policy changes, comprehensive OLM guidelines are necessary, including risk management strategies.

• Journal of Intelligence and Information Systems
• /
• v.7 no.1
• /
• pp.161-175
• /
• 2001

In this paper, a detection method of contradiction between input informations is proposed when the inference is processed in rule-based systems. The proposed method is accomplished by improving the label representation and the label management scheme in a conventional ATMS(Assumption-based Truth Maintenance System). The Proposed method also can represent and process input informations having uncertainty values.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.14 no.7
• /
• pp.552-559
• /
• 2002

The fault detection and diagnosis (FDD) technology may be applied in order to decrease the energy consumption and the maintenance cost of the air conditioning system. In this study, rule bases and curve fitting models were used to detect faults in an air handling unit. Gradually progressed faults, such as the fan speed degradation, the coil water leakage, the humidifier nozzle clogging, the sensor degradation and the damper stoppage, were applied to the developed FBD system. Simulation results show good detections and diagnoses of these faults. Therefore, this method may be effectively used for the fault detection and diagnosis of the air handling unit.

• Journal of KIBIM
• /
• v.9 no.2
• /
• pp.21-28
• /
• 2019

Recently, many scan projects are gradually increasing for maintenance, construction. The scan data contains useful data, which can be generated in the target application from the facility, space. However, modeling the scan data required for the application requires a lot of cost. In example, the converting 3D point cloud obtained from scan data into 3D object is a time-consuming task, and the modeling task is still very manual. This research proposes Scan-to-Geometry Mapping Rule Definition (S2G-MD) which maps point cloud data to geometry for irregular building plane objects. The S2G-MD considers user use case variability. The method to define rules for mapping scan to geometry is proposed. This research supports the reverse engineering semi-automatic process for the building planar geometry from the user perspective.

• Journal of Energy Engineering
• /
• v.20 no.3
• /
• pp.200-208
• /
• 2011

KHNP (Korea Hydro & Nuclear Power Co.) defines and manages equipment of Nuclear Power Plants systematically with functional importance determination of each equipment for efficient maintenance and optimal preventive maintenance. But the existing functional importance determinations have some different results between the plants, systems and engineers due to gap of understanding of classification criteria because they have been done in terms of equipment level rather than function level. so that caused the repeated work. To make up for this problem improve methodology of functional importance determination using MR (Maintenance Rule) and do classification of equipment for new nuclear power plants based on function level. In addition, methodical documentation for basis of importance determination is done to help that system engineers can easily understand and use.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.4 no.2
• /
• pp.185-191
• /
• 2000

The safety problem of aged tunnels has been emphasized. For the effective maintenance, site inspection of tunnel structures and surrounding grounds are required periodically. Also, the determination of safety of tunnels is not a simple problem. So the role experienced engineer in the maintenance is very important and development of an expert system that can perform as the engineers, has been needed. In this study, from the results of numerical analysis in several case, new precision inspection rules which can substitute actual numerical analysis are determined by a commercial program FLAC and regression analysis under various parameters such as material property, lining thickness, overburden and laterial coefficients. They are added to the knowledge base to determine safety of tunnel lining. To verify the expert system, the results are compared with an existing tunnel diagnosis report. It can be concluded that the new rule are well represented the actual numerical analysis under various site conditions. Therefore it is expected that the systematic management for effective maintenance of tunnel structure will be possible.