• Child Health Nursing Research
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• v.10 no.3
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• pp.251-261
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• 2004

Purpose: To investigate the degree and sources of stress which fathers of infants in NICU experience. Method: Eighty-five fathers of NICU infants at 5 university hospitals in Seoul volunteered to complete the Parental Stressor Scale for NICU (PSS: NICU) from September 1, to October 15, 2002. Result: Total perceived stress was 3.50±0.76. The highest score were in Parental Role Alteration (3.76±0.83) and Appearance and Behavior (3.65±1.04). The total perceived stress score (PSS), correlated significantly with method (t=3.50, p=.01), and route (F=5.30, p=.00) of feeding. Light & Sound correlated significantly with birth weight (F=3.39, p=.02), medical diagnosis(F=2.30, p=.03), plan of operation(t=2.50, p=.01), operation (t=3.80, p=.02), method (F=4.90, p=.003), and route (F=4.70, p=.00) of feeding. Infant Appearance and Behavior correlated significantly with birth weight (F=5.12, p=.01), plan of operation (t=2.50, p=.01), method (F=3.50, p=.01), and route (F=7.80, p=.00) of feeding. Parental Role Alteration correlated significantly with care of incubator (t=-.68, p=.03), method of feeding (F=2.80, p=.04) and education level of father (F=3.00, p=.05). Conclusion: Father with NICU infants were concerned mostly with parental role alteration and infant appearance. Nursing intervention should include fathers of NICU infants.

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.655-669
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• 1995

Restorative procedures can lead to weakening tooth due to reduction and alteration of tooth structure. It is essential to prevent fractures to conserve tooth. Among the several parameters in cavity designs, cavity isthmus is very important. In this study, amalgam 0 cavity was prepared on maxillary first premolar. Two dimensional finite element models were made by serial photographic method and isthmus(1/4, 1/3, 1/2, 2/3 of intercuspal distance) were varied. Three or four-nodal mesh were used for the two dimensional finite element models. The periodontal ligament and alveolar bone surrounding the tooth were excluded in these models. 1S model was sound tooth with no amalgam cavity. B model was assumed perfect bonding between the restoration and cavity wall. Both compressive and tensile forces were distributed directly to the adjacent regions. A load of 500N was applied vertically at the first node from the lingual slope of the buccal cusp tip. This study analysed von Mises stress, 1 and 2 directional normal stress and Y and Z axis translation with FEM software Super SAPII Version 5.2 (Algor Interactive System Co.) and hardware 486 DX2 PC. The results were as :follows : 1. 1S model was slightly different with 1B model in stress distibution. 1S, 2B, 3B, 4B models showed similiar stress distribution. 2. 1S model and four B models showed similiar pattern in Y axis and Z axis translation. 3. 1S model and four B models showed the bending phenomenon in the translation. 4. As increasing of the width of the cavity, experimental group was similiar with the control group in stress distribution. 5. As increasing of the width of the cavity, experimental group was similiar with the control group in Y and Z axis tranlation.

• Journal of the Institute of Convergence Signal Processing
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• v.16 no.2
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• pp.50-55
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• 2015

The noise of MRI shooting is 100dB loud and has an intensive psychological and physiological influences on the human body. ECG signals were measured by experimental methods, while wearing earplugs for 15 minutes in the stable state. Then the ECG signals were measured for 30 minutes while listening to about 100dB of sound in a MRI equipment. In this study, the heart rate variability of men and women was analyzed according to the MRI noise stress level through the frequency analysis. As the MRI noise level is about 100dB, HRV analysis resulted in an imbalance between the sympathetic and parasympathetic. During the period from the resting state up to 10 minutes, the maximum stress state was shown. This study will encourage MRI workers to take interests in hearing protection for the patient and to make objective indicators about MRI noises.

• Tunnel and Underground Space
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• v.25 no.2
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• pp.144-154
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• 2015

Mechanical energy is accumulated in the object when stress is exerted on rock specimens, and the failure is occurred when the stress is larger than critical stress. The accumulated energy is emitted as various forms including physical deformation, light, heat and sound. Uniaxial compression strength test and point load strength test were carried out in low temperature environment, and thermal variation of rock specimens were observed and analyzed quantitatively using thermal infrared camera images. Temperature of failure plane was increased just before the failure because of concentration of stress, and was rapidly increased at the moment of the failure because of the emission of thermal energy. The variations of temperature were larger in diorite and basalt specimens which were strong and fresh than in tuff specimens which were weak and weathered. This study can be applied to prevent disasters in rock slope, tunnel and mine in cold regions and to analyze satellite image for predicting earthquake in cold regions.

• Transactions of Materials Processing
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• v.16 no.4 s.94
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• pp.293-298
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• 2007

Recently, there is a need to produce a large forged part for the flight, shipping, some energies, and military industries, etc. Therefore, an open die forging technique of cast ingots is required to obtain higher quality of large size forged parts. Cogging process is one of the primary stages in many open die forging processes. In the cogging process prior to some open die forging processes, internal cavities have to be eliminated for defect-free. The present work is concerned with the elimination of the internal cavities in large ingots so as to obtain sound products. In this study, hot compression tests were carried out to obtain the flow stress of cast microstructure at different temperature and strain rates. The FEM analysis is performed to investigate the overlap defect of cast ingots during cogging stage. The measured flow stress data were used to simulate the cogging process of cast ingot using the practical material properties. Also the analysis of cavity closure is performed by using the $DEFORM^{TM}-3D$. The calculated results of cavity closure behavior are compared with the measured results before and after cogging, which are scanned by the X-ray scanner. From this result, the criteria for deformation amounts effect on the cavity closure can be investigated by the comparison between practical experiment and numerical analysis.

• Smart Structures and Systems
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• v.21 no.6
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• pp.715-725
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• 2018

Truss-Z (TZ) is an Extremely Modular System (EMS). Such systems allow for creation of structurally sound free-form structures, are comprised of as few types of modules as possible, and are not constrained by a regular tessellation of space. Their objective is to create spatial structures in given environments connecting given terminals without self-intersections and obstacle-intersections. TZ is a skeletal modular system for creating free-form pedestrian ramps and ramp networks. The previous research on TZ focused on global discrete geometric optimization of the spatial configuration of modules. This paper reports on the first attempts at structural optimization of the module for a single-branch TZ. The internal topology and the sizing of module beams are subject to optimization. An important challenge is that the module is to be universal: it must be designed for the worst case scenario, as defined by the module position within a TZ branch and the geometric configuration of the branch itself. There are four variations of each module, and the number of unique TZ configurations grows exponentially with the branch length. The aim is to obtain minimum-mass modules with the von Mises equivalent stress constrained under certain design load. The resulting modules are further evaluated also in terms of the typical structural criterion of compliance.

• Structural Engineering and Mechanics
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• v.44 no.6
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• pp.815-837
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• 2012

A plated beam is strengthened by bonding a thin plate to the tension face; it often fails because of premature debonding of the thin plate from the original beam in a brittle manner. A sound understanding of the mechanism of such debonding failure is very important for the effective use of this strengthening technique. This paper presents an improved analytical solution for interfacial stresses that incorporates multiple loading conditions simultaneously, including prestress, mechanical and thermal loads, and the effects of adherend shear deformations and curvature mismatches between the beam and the plate. Simply supported beams bonded with a thin prestressing plate and subjected to both mechanical and thermal loading were considered in the present work. The effects of the curvature mismatch and adherend shear deformations of the beam and plate were investigated and compared. The main mechanisms affecting the distribution of interfacial stresses were analyzed. Both the normal and shear stresses were found to be significantly influenced by the coupled effects of the elastic moduli with the ratios $E_a/E_b$ and $E_a/E_p$.

• IE interfaces
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• v.18 no.2
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• pp.158-166
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• 2005

Human-error and mental stress caused by psychophysiological dissonance between people and artificial environments have become a social problem. And it is a common knowledge that comfort environment reduces human-error and mental stress. Comfort sensibility is related to complex interactions between fabric, climatic, physiological and psychological variables. Currently, comfort sensibility has been evaluated by many sensory tests. However, it is difficult to evaluate comfort sensibility because a concrete concept of comfort sensibility is hard to define. In this paper, we propose a model to evaluate the comfort sensibility using Fuzzy-weighted score on an individual's subjective state for the stimulus. To represent the degree of comfort sensibility level for the stimulus, we represent comfort sensibility using 2 dimensional sensibility vector model. And we use the fuzzy-weighted score that is a fuzzy version of the weighted checklist technique computerized for evaluating the subjects. As an example, this model is applied to 1/f fluctuation sound evaluation. The results show that this model can be effectively used to the quantitative evaluation of comfort sensibility for the stimulus.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.651-655
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• 2004

This paper studies the designing method and application for grommets, rubber material used to absorb vibration on the air conditioner compressor. The existing grommet with hardness 40 degrees, EPDM, has the high transmissibility on the compressor that causes additional structure born sound. The problem for EPDM is transformation over long time usage possibly due to its design in which stress is concentrated on a certain position. In order to resolve it, silicon material was previously used with the same design in some models. The vibration performance did improve, but the cost became high. Below are the major developments regarding improvements in compressor rubber material, vibration performance and durability through design change, and new grommet to attain cost reduction. 1 The optimum grommet design for stress even distribution through FEM methods. 2. Comparison for grommet material and design for improved transmissibility. 3. Assess for grommets durability and product applications.

• The Journal of the Acoustical Society of Korea
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• v.26 no.7
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• pp.306-316
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• 2007

Based on a concept of soundscape, this study aims to investigate Koreans' preference for auditory elements, features, and impressions depending upon the season, and examine how these auditory factors of soundstape and seasons interact with each other and attempt to discover their influence on people's auditory preferences. According to an environmental psychological approach called the caption evaluation method, 45 college students examined the soundscape of Namwon City while racing the streets in four seasons. In order to analyze the interactions between seasons and such auditory factors as elements, features, and impressions, it was conducted the GLM univariate analysis and the NPAR tests for independent samples. The results of the analyses show that there are interactive effects between seasons and auditory factors like elements, features, and impressions and that the auditory factors have an effect on auditory preference. Moreover, as for seasonal preference for auditory elements, it was found that people prefer natural sound in spring, summer, and fall while they prefer social sound in winter. Concerning seasonal preference for auditory features, people place a focus on the behaviors in spring, summer, and winter while they stress the surroundings in autumn, as for seasonal preference for auditory impressions, they make much of sound characteristics in spring and winter but they value the atmosphere of streets in summer and fall. The results of this study can he utilized as useful data in determining which auditory factors among elements, features, and impressions to take into consideration in a soundscape design.