• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.264-270
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• 1998

This research broadens the prime concern of nuclear power plant operations from safe performance to both economic and safe performance. First emergency diesel generator is identified as one of main contributors for the lost plant availability through the review of plants forced outage records. The framework of an integrated architecture for performing modern on-line condition for operational availability improvement is configured in this work. For the development of the comprehensive sensor networks for complex target systems, an integrated methodology incorporating a structural hierarchy, a functional hierarchy, and a fault-system matrix is formulated. The second part of our research is development of intelligent diagnosis and maintenance advisory system, which employs Bayesian Belief networks (BBNs) as a high level reasoning tool incorporating inherent uncertainty use in probabilistic inference. Our prototype diagnosis algorithms are represented explicitly through topological symbols and links between them in a causal direction. As new evidence from sensor network development is entered into the model especially, our advisory of system provides operational advice concerning both availability and safety, so that the operator is able to determine the likely modes, diagnose the system state, locate root causes, and take the most advantageous action. Thereby, this advice improves operational availability

• Journal of Welding and Joining
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• v.15 no.5
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• pp.64-73
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• 1997

Deformations of structures due to welding appear much complicated and deformated modes are also complex. As parameters governing deformations are various and effect of parameters on deformations is not well known, precise prediction of deformation due to welding has been a difficult problem. Until now, many research papers as to welding deformation have been published, but the research results can explain only one aspect of welding deformation have been published, but the research results can explain only one aspect of welding deformation and are hard to be used in reasonable prediction of welding deformations in complicated structures. In this study, based on the accumulated results concerning to welding deformations, a practical method to predict complicated welding deformations of large structure is proposed. A simplified model to estimate residual plastic strains is suggested and main parameters affecting residual plastic strains are shown to be heat input and joint restaints. Inherent strain theory and experimental data are combined with the finite element method and welding deformations of large structures are calculated by elastic analysis. Comparison of calculated results with experimental data shows the accuracy and validity of the proposed method.

• Journal of Korean Society for Geospatial Information Science
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• v.3 no.2 s.6
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• pp.199-211
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• 1995

Bus, Which is together with subway the main part of public transportation modes in the city, is reviewed for the development of an optimal feeder-bus service area. Based on the IDRISI of GIS package, and taking into account of the convenience of downtown-oriented public transportation users at peak time, a model for the development of feeder-bus service area and a solution and introduced. Major result in this study is as follows: Development is given to a model that is designed to overcome the shortage of the existing models, which has limits in simulating the real situation; Variables were used in combination so that bus and subway route, station spacing, and operating frequency can be determined simultaneously, which enables to elucidate the mutual relationship and the structure in public transportation system. A model for feeder-bus area development is also given applied to determination and opening of subway and urban express bus route and new transportation systems. The model developed in this paper is useful in the case of extension and opening of subway and urban express bus route and new transportation Systems.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.177-182
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• 2003

In this study, a performance model of the Smart UAV propulsion system with ducts, tip jets and variable main nozzle, which has flight capability of the rotary wing mode for the take-off/landing and low speed forward flight as welt as the fixed wing mode for high speed forward flight, has been newly developed. With the proposed model, steady-state performance analysis was performed at various flight modes and conditions, such as rotary wing mode, fixed wing mode, compound wing, mode altitude and flight speed. In investigation of performance analysis, it was noted that the operational capability of the propulsion system was limited due to the duct losses depending on each flight mode, and the limitation with the altitude variation case has much greater than that with the flight speed variation case.

• Journal of Korean Public Health Nursing
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• v.19 no.1
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• pp.64-73
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• 2005

The purpose of this study was to discuss the difference of stress by the grade, examine the relationship between characteristics and main stress, and to investigate the effect of the National Examination of Registered Nurses on stress by using the stress self-rating scale targeting university nursing students (n=314), The stress self-rating scale consists of three subscales: stress responses, stressors and coping parts, such as perceived social support and a sense of humor. The data were analyzed by descriptive statistics, t-test, Pearson's correlation coefficient and regression analysis. The results showed that passing the National Examination of Registered Nurses was the first problem among the stressors. Stressors of the living factors and nursing factors, and subjective stressors of the surveyed nursing students were the highest among the senior students, but stressors of nursing factors increased according to the grade of the nursing students. Perceived stress responses were high in psychological responses of other aspects, and perceived stress responses increased according to the grade (p<.001). Senior students had a high weight of perceived stress responses (problem-focused, emotion-focused). and active and negative coping modes. Significant factors that explained the stressors were coping mode(r=.62-82. p<.01) and cognition(r=.19. p<.01). including the social support. These findings suggest that social support was very important for seniors. and that we have to develop approaches to decrease stress according to the student grade for nursing education process.

• The Journal of the Acoustical Society of Korea
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• v.36 no.3
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• pp.186-193
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• 2017

Silla Great Bell was manufactured in order to ring for the new millennium in succession to King Seongdeok Divine Bell. This study investigates how Silla Great Bell is similar to King Seongdeok Divine Bell in respect of structure and sound. First, design and manufacturing processes are introduced and dimensions of the two bells are compared and the similarity is estimated. Three main characteristics of the sound of a Korean bell are magnificent and harmonic striking sound, dynamic beat, and long lasting hum tone. These three features are compared and objectively estimated using physical parameters. The purpose of the study is to provide useful information to manufacture Korean bell which has beautiful appearance and excellent sound.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.509-516
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• 2003

In tile design of base isolation system for building and short-span bridge, shift of the natural period of the structure is main objective. But, most long-span bridges such as a cable-stayed bridges have a number of long-period modes due to their flexibility and small structural damping. thus the design concept of base isolation system for building and short-span brigde may be difficult to use directly to these structures. However, the effectiveness of LRB for cable-stayed bridges is indicated by Ali and Abdel-Ghaffar. In this study, the design procedure and guidelines of LRB for a seismically excited cable-stayed bridge are investigated. The design properties of LRB are chosen that the design index(DI) is minimized or little changed for variation of properties. This result show that the stiffer rubber and bigger lead core size are need to cable-stayed bridges. And the seismic performance of designed LRB is also investigated. The consequences show that the perforamnce of designed LRB is better than that of Naeim-Kelly mettled designning LRB for general building structures. Moreover, the design properties of LRB are researched to several diffrent dominant frequency of earthquake. The results present that the plastic and elastic stiffness of LRB are affected by the dominant frequency of earthquake.

• Journal of Haehwa Medicine
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• v.9 no.2
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• pp.223-239
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• 2001

A literature study on cancer therapy of warm-hot oriental medicine was done, and the results were as follows. 1. In oriental medicine, oncogens are six exopathogens, seven modes of emotion, overwork, pathogenic factors, and especially related with pathologic cold situation. 2. There are many capillaries in tuomr, and because temperature of inner space of tumor is higher than normal organization. Tumor cell has a character which is weak for high temperature. 3. Warm-hot herb drugs have effects of dissipating mass, warming kidney to reinforce yang and dispering, so it has a function of suppressing tumor as well as improving immunity in cancer therapy. 4. In traditional medical books, main prescriptions of cancer therapy are xinzhiyinyanggongjiwan(新製陰陽攻積丸), qianjinxiaoshiwan(千金硝石丸), feiqiwan(肥氣丸), xibenwan(息賁丸), fuliangwan(伏梁丸), beiqiwan, bentunwan(賁豚丸), zengsunwujiwan(增損五積丸), and these are composed of warm-hot herb drugs. 5. In current, the study of warm-hot drugs is progressed in immunological capacity, anti-tumor activity, stimulating bone marrow and regulating hormone secretion. It will be expected that advanced study of these must be accomplished in cancer patients.

• Smart Structures and Systems
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• v.15 no.3
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• pp.523-541
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• 2015

Structural health monitoring of steel truss bridge based on changes in modal properties was investigated in this study. Vibration measurements with five sensors were conducted at an existing Warren truss bridge with partial fractures in diagonal members before and after an emergency repair work. Modal properties identified by the Eigensystem Realization Algorithm showed evidences of increases in modal damping due to the damage in diagonal member. In order to understand the dynamic behavior of the bridge and possible mechanism of those increases in modal damping, theoretical modal analysis was conducted with three dimensional frame models. It was found that vibrations of the main truss could be coupled internally with local vibrations of diagonal members and the degree of coupling could change with structural changes in diagonal members. Additional vibration measurements with fifteen sensors were then conducted so as to understand the consistency of those theoretical findings with the actual dynamic behavior. Modal properties experimentally identified showed that the damping change caused by the damage in diagonal member described above could have occurred in a diagonal-coupled mode. The results in this study imply that damages in diagonal members could be detected from changes in modal damping of diagonal-coupled modes.

• Wind and Structures
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• v.22 no.6
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• pp.685-701
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• 2016

Downbursts are of great harm to transmission lines and many towers can even be destroyed. The downburst wind field model by Chen and Letchford was applied, and the wind loads of two typical transmission towers in inland areas and littoral areas were calculated separately. Spatial finite element models of the transmission towers were established by elastic beam and link elements. The wind loads as well as the dead loads of conductors and insulators were simplified and applied on the suspension points by concentrated form. Structural analysis on two typical transmission towers under normal wind and downburst was completed. The bearing characteristics and the failure modes of the transmission towers under downburst were determined. The failure state of tower members can be judged by the calculated stress ratios. It shows that stress states of the tower members were mainly controlled by 45 degree wind load. For the inland areas with low deign wind velocity, though the structural height is not in the highest wind velocity zone of downburst, the wind load under downburst is much higher than that under normal wind. The main members above the transverse separator of the legs will be firstly destroyed. For the littoral areas with high deign wind velocity, the wind load under downburst is lower than under normal wind. Transmission towers are not controlled by the wind loads from downbursts in design process.