• Proceedings of the KIEE Conference
• /
• 2006.11a
• /
• pp.357-359
• /
• 2006

Traditional time based preventive maintenance is used to constant maintenance interval for equipment life. In order to consider economic aspect for time based preventive maintenance, preventive maintenance is scheduled by RCM(Reliability-Centered Maintenance) evaluation. So, Markov state model is utilized considering stochastic state in RCM. In this paper, a Markov state model which can be used for scheduling and optimization of maintenance is presented. The deterioration process of system condition is modeled by a Markov model. In case study, simulation results about RCM are used to the real historical data of combustion turbine generating units in Korean power systems.

• Proceedings of the KSRS Conference
• /
• 2006.03a
• /
• pp.202-205
• /
• 2006

The objective of this study is to analyze the hazard-areas for landslide using GIS and RS. LRA (Logistic Regression Analysis) and AHP (Analytic Hierarchy Program) methods were used for evaluation of the hazard-areas by six topographic factors (slope, aspect, elevation, soil drain, soil depth, land use). These methods were applied to Anseong-si where frequent landslides were occurred mainly by the regional heavy rainfall. A landslide hazard-map of Anseong-si could describe into 7 hazard-grades. As results, LRA method was underestimated in higher grades areas, while AHP method was underestimated in lower grades areas. In order to evaluate the hazard-areas for landslides with accuracy, these results of each method were overlapped and the results of suggested method were compared with the historical landslide hazard records of KFRI (Korea Forest Research Institute).

• Smart Structures and Systems
• /
• v.14 no.3
• /
• pp.367-376
• /
• 2014

Ambient vibration techniques are nowadays a very popular tool to assess dynamic properties of buildings. Due to its non destructive character, this method is particularly valuable, especially for health monitoring of historical monuments. The present ambient vibration experiment consists on the evaluation of vibration modes of a Medieval tower. Situated in Soncino (close to Cremona, in the Northern Italian region named Lombardia), the tower of 41.5 meters height has been monitored by seismometers located at different points inside the structure. Spectral ratios of the recorded ambient vibrations clearly identify a fundamental mode at about 1 Hz, with a slight difference in the two horizontal components. A second mode is also evidenced at approx 4-5 Hz, with a moderate degree of uncertainty. The records of a ML 4.4 earthquake, occurred during the monitoring period, confirm the information obtained by microtremor analysis. Daily variations of both 1st and 2nd mode were detected: these variations, of an amount up to 2%, seem to be well related with the temperature.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2006.11a
• /
• pp.71-74
• /
• 2006

This study shows the historical background, and work flow of PRA (Probabilistic Risk Assessment) method which devised by NASA during the space development. It also illustrates the possibility of adoption of the method to evaluation of reliability KSLV project.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
• /
• v.15 no.1
• /
• pp.3-13
• /
• 2004

A historical overview of the relationship between law and medicine, particularly psychiatry, was presented along with the religious, social and legal aspects of the societies in the Western hemisphere as they affected the concepts and philosophy of the legal system in each society at different point in history. The evolution of the modern concept of juvenile court system and changing patterns of implementing the juvenile law in the United States, particularly the mental health evaluation process to determine the youths' competence to stand trial, were presented in detail. The ultimate goals of protecting the civil rights of children, adolescents and youths are emphasized.

• International Journal of CAD/CAM
• /
• v.6 no.1
• /
• pp.125-137
• /
• 2006

Nowadays, many commercial CAD systems support history-based, constraint-based and feature-based modeling. Unfortunately, most systems fail during the re-evaluation phase when various kind of topological changes occur. This issue is known as "persistent naming" which refers to the problem of identifying entities in an initial parametric model and matching them in the re-evaluated model. Most works in this domain focus on the persistent naming of atomic entities such as vertices, edges or faces. But very few of them consider the persistent naming of aggregates like shells (any set of faces). We propose in this paper a complete framework for identifying and matching any kind of entities based on their underlying topology, and particularly shells. The identifying method is based on the invariant structure of each class of form features (a hierarchical structure of shells) and on its topological evolution (an historical structure of faces). The matching method compares the initial and the re-evaluated topological histories, and computes two measures of topological similarity between any couple of entities occurring in both models. The naming and matching method has been implemented and integrated in a prototype of commercial CAD Software (Topsolid).

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.2
• /
• pp.248-253
• /
• 2007

Traditional time based preventive maintenance is used to constant maintenance interval for equipment life. In order to consider economic aspect for time based preventive maintenance, preventive maintenance is scheduled by RCM(Reliability-Centered Maintenance) evaluation. So, Markov state model is utilized considering stochastic state in RCM. In this paper, a Markov state model which can be used for scheduling and optimization of maintenance is presented. The deterioration process of system condition is modeled by a Markov model. In case study, simulation results about RCM are used to the real historical data of combustion turbine generating units in Korean power systems.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.111-112
• /
• 2008

Although two types of uncertainty such as randomness and fuzziness simultaneously exist in power systems, yet they have been treated as distinct fields to evaluate the power system reliability. Thus, this paper presents a reliability assessment method based on a combined concept of fuzzy and probability. To reflect the two-fold uncertainty, a modified load duration curve(MLDC) is proposed using the probability distribution of historical load data in which a fuzzy model for the peak load forecast is embedded. IEEE RTS system was used to demonstrate the usefulness and applicability of the proposed method, and the reliability indices were obtained using the proposed MLDC. The results show a wider insight into impact of load fuzziness on uncertainties of reliability indices for power systems.

• Management Science and Financial Engineering
• /
• v.16 no.1
• /
• pp.17-46
• /
• 2010

This paper studies six different AHP (Analytic Hierarchy Process) approaches and suggests that the features of the approaches are classified by application circumstances in order to contribute to the applicability and quality usage of the AHP. Our study investigates the hierarchical principles and characteristics of the AHP, and historical debates on the AHP evaluation in which the six approaches have been involved. One of six approaches is an ANP (Analytic Network Process) application that is directly connected to AHP usage. The application differences among the six approaches are validated with a plain example. Then, the four circumstances of AHP applications are classified by two dimensions: the first dimension is whether or not the importance (weights) of criteria is independent of restrictively setting alternatives, and the second dimension is whether or not preference (priorities) of alternatives is independent of adding alternative(s) to or removing alternative(s) from the considering set of alternatives. Then featuring way of weighting criteria is classified. We suggest the distinguishing manners and describe the implications of the AHP application. Finally, we discuss rank reversal and multiplicative AHP.

• Korean Journal of Veterinary Research
• /
• v.53 no.3
• /
• pp.185-187
• /
• 2013

An 11-year-old, toy poodle dog was presented with dermatologic lesions and mammary gland tumor (MGT) evaluation. A solitary, lobulated MGT (size $2.5{\times}3.5$ cm) was affecting the 5th left mammary gland. Firm, oval plaque skin lesions were present on the left dorsal carpal area. The skin lesions were alopecic and salivary staining. The dog had historical separation anxiety and excessive licking of skin lesions were observed. Based on the clinical and histopathologic examinations, MGT was diagnosed with mammary complex adenoma and the skin lesions were diagnosed with acral lick dermatitis. Behavior modification treatment using oral clomipramine was effective.