• Composites Research
• /
• v.15 no.3
• /
• pp.18-29
• /
• 2002

The bending vibration and thermal flutter instability of spacecraft booms modeled as circular thin-walled beams of closed cross-section and subjected to thermal radiation loading is investigated in this paper. The thin-walled beam model incorporates a number of nonclassical effects of transverse shear, primary and secondary warping, rotary inertia and anisotropy of constituent materials. Thermally induced vibration response characteristics of a composite thin walled beam exhibiting the circumferantially uniform system(CUS) configuration are exploited in connection with the structural flapwise bending-lagwise bending coupling resulting from directional properties of fiber reinforced composite materials and from ply stacking sequence. The numerical simulations display deflection time-history as a function of the ply-angle of fibers of the composite materials, damping factor, incident angle of solar heat flux, as well as the boundary of the thermal flutter instability domain. The adaptive control are provided by a system of piezoelectric devices whose sensing and actuating functions are combined and that are bonded or embedded into the host structure.

• Journal of Korean Public Health Nursing
• /
• v.28 no.3
• /
• pp.432-444
• /
• 2014

Purpose: This descriptive study was conducted in order to investigate the research trends of past nursing studies related to disasters in Korea, and to identify the direction of future research. Methods: Fifty studies conducted from July 1995 to June 2014 were analyzed according to general characteristics, disaster phase, disaster type, and research theme based on the four areas and 10 domains of the ICN Framework of Disaster Nursing Competencies. Results: The majority of studies were designed using quantitative methods (29). In disaster type, 12 studies explored natural disasters, and 14 explored manmade disasters. Disaster responders were the subject of 31 studies. In relation to research topics, the majority of studies were in the area of preparedness competencies of the ICN Framework (26). The studies were concentrated in the domain of education and preparedness (24). Conclusion: The total number of studies on disasters had increased over the years, while the topics failed to deal with all domains of the ICN Framework. The results indicate that the future direction of nursing research on disasters is to be vitalized through the flexibility of research design, systematic approach based on global perspectives, research on emergency responders and vulnerable people, and research relating to community-based disaster nursing.

• Journal of Biomedical Engineering Research
• /
• v.34 no.3
• /
• pp.135-140
• /
• 2013

We have developed an ultra wide-field of view Optical Coherence Tomography(OCT) which has capability to 2D and 3D views of cross-sectional structure of in vivo human retina. Conventional OCT has a limitation in visualizing the entire retina due to a reduced field of view. We designed an optical setup to significantly improve the lateral scanning range to be more than 20 mm. The entire human retinal structure in 2D and 3D was reported in this paper with the developed OCT system. Also, we empirically searched an optimized image size for real time visualization by analyzing variation of the frame rate with different lateral scan points. The size was concluded to be $1024{\times}2000{\times}300$ pixels which took 9 seconds for visualization.

• Quality Improvement in Health Care
• /
• v.24 no.1
• /
• pp.23-29
• /
• 2018

Background: The purpose of this study was to examine undergraduate medical students' perceptions and intentions regarding patient safety during clinical clerkships. Methods: Cross-sectional and self-administered questionnaire survey was conducted on 34 students from one medical school using a modified version of the Medical Student Safety Attitudes and Professionalism Survey (MSSAPS). We assessed $4^{rd}-year$ medical students' perceptions of the cultures ('safety', 'teamwork', and 'error disclosure'), 'behavioural intentions' concerning patient safety issues and 'overall patient safety'. The overall response rate was 66.4%. Results: Among safety domains, "teamwork culture" was rated highest. "Error disclosure culture" received the lowest ratings. Regarding the error disclosure domain, only 10% of respondents reported that they have received education or training on how to disclose medical error to patients. Independent of survey domains, when students were asked "Overall, do you think your hospital is safe based on your clinical rotation?", 61.8% reported that the hospital was safe. Conclusions: Assessing students' perceptions of safety culture can provide clerkship directors and educators with information that enhances the educational environment and promotes patient safety. Discussions of medical errors, patient safety, and how best to incorporate an analysis of these issues into the existing curriculum are needed.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.3
• /
• pp.1761-1768
• /
• 2013

This cross-sectional and descriptive study was designed to determine symptoms emerging due to chemotherapy treatment and their effects on children's quality of life. The research was carried out between February 2008 and February 2009 at the pediatric oncology clinics in four hospitals, focusing on 93 patients receiving chemotherapy. A survey form, the Pediatric Quality of Life Inventory (PedsQL 4.0) and the Memorial Symptom Assessment Scale (MSAS) were used as data collection tools. Chi-square and Student t tests were performed for data analysis. Some 51.6% of the children were aged 13-15 years old, and 51.8% were boys and 50.5% were diagnosed as having solid tumors. There were significant relations between: antimetabolite chemotherapeutics and feeling irritable and worrying (p=0.001, p=0.030); vinkoalkaloid and numbness/tingling in hands/feet (p=0.043); antracyclines and lack of energy and skin changes (p=0.021, p=0.004); and corticosteroids and lack of appetite, nausea and sadness (p=0.008, p=0.009, p=0.009). Several symptoms such as feeling sad, worrying and feeling irritable caused a significant decrease in the total domain of quality of life scores (p=0.034, p=0.012, p=0.010, respectively). Chemotherapeutic drugs can cause symptoms that can seriously affect quality of life in children.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.11 no.1
• /
• pp.45-52
• /
• 2016

This paper suggests a new method of finding regularization parameter for image restoration problems. Wiener filter requires priori information such that power spectrums of original image and noise. Constrained least squares restoration also requires knowledge of the noise level. If the prior information is not available, separate optimization functions for Tikhonov regularization parameter are suggested in the literature such as generalized cross validation and L-curve criterion. In this paper, self-regularization method that connects bias term of augmented linear system and smoothing term of Tikhonov regularization is introduced in the frequency domain and applied to the image restoration problems. Experimental results show the effectiveness of the proposed method.

• Fibers and Polymers
• /
• v.1 no.1
• /
• pp.37-44
• /
• 2000

A finite element method is employed fer a flow analysis of the melt spinning process of a non-circular fiber, a PET(polyethylene terephthalate) filament. The flow field is divided into two regions of die channel and spin-line. A two dimensional analysis is used for the flow within the die channel and a three dimensional analysis fur the flow along the spin-line. The Newtonian fluid is assumed for the PET melt and material properties are considered to be constant except for the viscosity. Effects of gravitation, air drag force, and surface tension are neglected. Although the spin-line length is 4.5 m only five millimeters from the spinneret are evaluated as the domain of the analysis. Isothermal and non-isothermal cases are studied fer the flow within the die channel. The relationship between the mass flow rate and the pressure gradient is presented for the two cases. Three dimensional flow along the spin-line is obtained by assuming isothermal conditions. It is shown that changes in velocity and cross-sectional shape occur mostly in the region of 1mm from the die exit.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.41 no.5
• /
• pp.217-223
• /
• 2004

In block-based lossy video compression, severe quantization causes discontinuities along block boundaries so that annoying blocking artifacts are visible in decoded video images. These blocking artifacts significantly decrease the subjective image quality. In order to reduce the blocking artifacts in decoded images, many algorithms have been proposed. However studies on so called comer outlier, have been very limited. Corner outliers make image edges look disconnected from those of neighboring blocks at cross block boundary. In order to solve this problem we propose a corner outlier detection and compensation algorithm as loop-filtering in spatial domain. Experiment results show that the proposed method provides much improved subjective image quality.

• Wind and Structures
• /
• v.14 no.3
• /
• pp.221-238
• /
• 2011

The estimated response of large-scale engineering structures to severe wind loads is prone to modelling uncertainties that can only ultimately be assessed by full-scale testing. To this end ambient vibration data from full-scale monitoring of the historic Clifton Suspension Bridge has been analysed using a combination of a frequency domain system identification method and a more elaborate stochastic identification technique. There is evidence of incipient coupling action between the first vertical and torsional modes in strong winds, providing unique full-scale data and making this an interesting case study. Flutter derivative estimation, which has rarely previously been attempted on full-scale data, was performed to provide deeper insight into the bridge aerodynamic behaviour, identifying trends towards flutter at higher wind speeds. It is shown that, as for other early suspension bridges with bluff cross-sections, single-degree-of-freedom flutter could potentially occur at wind speeds somewhat below requirements for modern designs. The analysis also demonstrates the viability of system identification techniques for extracting valuable results from full-scale data.

• Advances in aircraft and spacecraft science
• /
• v.4 no.4
• /
• pp.467-486
• /
• 2017

A method for decoupling reliability based design optimization problem into a set of deterministic optimization and performing a reliability analysis is described. The inner reliability analysis and the outer optimization are performed separately in a sequential manner. Since the outer optimizer must perform a large number of iterations to find the optimized shape and size of structure, the computational cost is very high. Therefore, during the course of this research, new multilevel reliability optimization methods are developed that divide the design domain into two sub-spaces to be employed in an iterative procedure: one of the shape design variables, and the other of the size design variables. In each iteration, the probability constraints are converted into equivalent deterministic constraints using reliability analysis and then implemented in the deterministic optimization problem. The framework is first tested on a short column with cross-sectional properties as design variables, the applied loads and the yield stress as random variables. In addition, two cases of curvilinearly stiffened panels subjected to uniform shear and compression in-plane loads, and two cases of curvilinearly stiffened panels subjected to shear and compression loads that vary in linear and quadratic manner are presented.