• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.28.2-28.2
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• 2015

High redshift quasars (z > 5) hold keys to understanding the evolution of the universe in its early stage. Yet, the number of high redshift quasars uncovered from previous studies is relatively small (70 or so), and are concentrated mostly in a limited redshift range (z ~ 6). To understand the early mass growth of supermassive black holes and the final stage of the cosmic reionization, it is important to find a statistically meaningful sample of quasars with various physical properties. Here we present a survey for high redshift quasars at 5 < z < 7. Through color selection techniques using multi-wavelength data, we found quasar candidates and carried out imaging follow-up observations to reduce contaminants. After optical spectroscopy, we discovered eight new quasars. We obtained near-infrared spectra for 3 of these 8 quasars, measured their physical properties such as black hole masses and Eddington ratios, and found that the high redshift quasars we discovered are growing via accretion more vigorous than those of their lower redshift counterparts. We estimated the quasar number densities from our discoveries and compared them to those expected from the quasar luminosity functions in literature. In contrast to the observed number density of quasars at z ~ 5, which agrees with literature, the observed number density at z ~ 7 shows values lower than what is expected, even after considering an extrapolated number density evolution. We conclude that the quasar number density at z ~ 7 declines toward higher redshift, more steeply than the empirically expected evolution.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.1
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• pp.36-43
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• 2017

A drug infuser is a well-known device that is widely used in various areas of clinical practice. However, some materials used in the drug infuser have been developed for particular purposes and thus, their design characteristics have to be changed considerably. Especially, the implications of a new filler in the drug infuser have migrated to the areas of body corrections in plastic surgery. In this study, the design process of a drug infuser managing a large content volume has been studied from the perspective of structure safety. A new design of the drug infuser that uses a 10 cc filler with high viscosity is presented. Finite element analysis is used to confirm that the assembled drug infuser is safe enough to hold the required loading of 490 N. Furthermore, the final prototype of the drug infuser was successful in reducing the weight up to 400 g without compromising the safety.

• Journal of the Korea Furniture Society
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• v.10 no.1
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• pp.33-42
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• 1999

This study aims to organize the research ways of interior design for clothing stores as a management strategy in the market changing rapidly. The public met their needs in a mass production system. However, the brand-name companies began to create the conditions of consumption for people, there appeared people with new lifestyles and new way of thoughts so that their propensity to consume resulted in consumption activities, and it become varied, individual, and highly qualified. Therefore, in view of consumers' priority, based on SI sales environment this paper aims to create a new image by re-designing the interior and furniture of shops which will help to enhance the image of brand name. Therefore, the brand-name companies will expect a large sale for the new product and it will apply to sales environments of other products and influence them. The purpose of this paper is to find a desirable way to increase sales efficiency for the companies. In order to get a concept and propriety of sales environment design, examined mutual relation to each study of interior design, marketing, and fashion design. Through referring to the documents research of these fields I could get a conception and basic structure for them. Based on the theoretical knowledge, this study was made to show to examine and generalize the existing sales environments and situations and set up a new concept for this. It will apply to interior design and store holds and present a new design alternative for improvement.

• 한국경영정보학회:학술대회논문집
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• 2008.06a
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• pp.383-393
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• 2008

Online games are the popular topic due to the increased total online game market volume nowadays. And many studies on online games are released. But most studies used the questionnaire method that reveals only section of the situation like a snapshot. For this reason, previous studies have a little limitation that does not show dynamical changing issues like a product life cycle and changes in customer's mind Because of this, we studied on online games with the system dynamic model which can show dynamic simulations to analysis time series data. We chose MMORPG (Massively Multi-play Online) RPG (Role Playing Game) in sort of online games because it has many absorbing factors and enthusiastic users. We designed the simulation model which analyzes the influences of update and CRM strategy on users. We put the game developer who is ready for updated version game and released that periodically and focused on dormant users who used to be enthusiastic about MMORPG. The simulation results showed that the update has positive influences on new users gathering and hold established users. And CRM strategies help to prevent dormant users from transferring to rivals by offering them re-absorbing factors. Through this study, we confirmed the importance of update on online games and the necessity of introducing CRM strategy in the online game market.

• Journal of Biosystems Engineering
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• v.15 no.3
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• pp.177-185
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• 1990

The break of rotary blade is occured from a stress concentration of the inside of blade by the outside impulsive load. In order to examine its inside stress and stress concentration of rotary blade, a epoxy plate which is suitable to applicate by photoelastic system is used to experiment. These results are summarized as follow. 1. Refer to the existence of bolt hole and a size of its of rotary blade, a stress concentration which cause the break of rotary blade is not exposed. 2. It is expected to be break to section of hold of rotary blade and the break of this is due to that there are concentrated by shearing force, bending moment and bending stress. 3. When the crack which caused from processing are set up to any location, the stress concentration taken to the creak point. 4. Without regard to the location of the reaction points of rotary blade, the bending stress which is greated than the bending moment is occured within about 6 em toward the center line of bolt hole and it was possible to break that section.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.37-41
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• 2007

Fast Fourier Transformation(FFT) is one of the most useful way to analyze response signal for the purpose of grasping the dynamic characteristics of system. Excitation is a factor or process making noise or vibration. It's typical and simple experimental method widely used for catching hold of dynamic peculiar characters and modal behaviors of system by frequency analysis. There are harmonic excitation, impact excitation, random excitation, sweep excitation, chirp excitation and so on as the ideal method in an experiment using exciter. In this thesis, excitation testing module for NI-PXI equipment is developed. The analyzing module is developed with LabVIEW tool. A user can generate each waveform for shaking a structure and see quickly and easily modal shape of system with this module. This developed module will be expected to build up more convenient and serviceable measurement system.

• Asian Oncology Nursing
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• v.11 no.1
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• pp.26-32
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• 2011

Purpose: The purpose of this study was to analyze the trend of cognitive developmental interventions on patients with breast cancer who underwent chemotherapy. Methods: The researcher searched databases and selected 17 literatures using chemotherapy, breast cancer, cognitive function and intervention as searching key words. Searched databases included Ovid, Pubmed, Proquest and Medline and data collection period was from January 2000 to May 2010. Results: Interventions for patients with breast cancer have been continuously developed and frequent research topics included breast cancer, chemotherapy, quality of life, and cognitive function. In terms of study design, four research articles were pre-experimental study designs, one was case study, and the rest of studies were non-equivalent pretest-posttest control group design. Effects of intervention were examined in only 5 studies among 17. The interventions were not found to have direct effects in cognitive improvement. Conclusion: It is needed to figure out the mechanism of cognitive deterioration of the patients with breast cancer who underwent chemotherapy. And nursing interventions needs to be developed in order to hold up the cognitive downhill and help their cognitive rehabilitation.

• Journal of Korean Public Health Nursing
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• v.12 no.1
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• pp.37-54
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• 1998

For the purpose of investigating the job implementation of industrial health nurses catch hold of satisfaction, relational character of influence. A questionnaire survey was carried out on 131 nurses who employed at the manufacture of electronic products$(27.1\%)$, distribution industry$(38\%)$, service station$(22\%)$, construction$(10\%)$, et cetra The tool of this study was modified as completed from kang's(l991) checklist of questions were composed of the performance of nurses' duty(13 items), the factor of main influential character of nurses' job(11 items), job satisfaction(26 items). The results were as follows. 1. Industrial health nurses worked to labor follow up study after physical examination$(100\%)$, medication$(97.1\%)$, workers regular physical examination(95.5%), dressing$(94.1\%)$. 2. The factor of influence of job performance were personal relation$(100\%)$, satisfaction of nurses job performance$(86.7\%)$, environment of workplace$(86.7\%)$. 3. A period of long work experienced nurses felt the highest satisfaction as 3.44 point.

• Environmental Engineering Research
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• v.23 no.2
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• pp.195-204
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• 2018

A pilot scale study was conducted on a down-flow hanging sponge (DHS) reactor installed at a sewage treatment plant in Banda Aceh, Indonesia for treatment of desludging septic tank wastewater. Raw wastewater with an average biochemical oxygen demand (BOD) and total suspended solids of 139 mg/L and 191 mg/L, respectively, was pumped into the reactor. Two different hydraulic retention times (HRTs, 3 h and 4 h) were investigated, equivalent to organic loadings of 1.11 and $0.78kg\;BOD/m^3/d$, respectively. The average BOD concentration in the final effluent was 46 and 26 mg/L at HRTs of 3 and 4 h, respectively. The concentration of retained sludge along the reactor height was 10.2-18.7 g VSS/L-sponge, and the sludge activities were 0.24-0.32 and 0.04-0.40 mg/g VSS/h for heterotrophs and nitrification, respectively. Values of water hold-up volume, dispersion coefficient, and number of tank in-series found from tracer studies of clean sponge and biomass-loaded sponge confirmed that growth of retained sludge on the sponge module improved hydraulic performance of the reactor. Adoption of the DHS reactor by this Indonesian sewage treatment plant would enhance the role of the current desludging septic tank wastewater treatment system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8C
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• pp.598-604
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• 2008

The hold-type display panel such as a liquid crystal displays(LCD) has problem of motion blur. The problem can be improved by a Frame Rate-up Conversion(FRC) using a frame interpolation. We propose a Motion Estimation(ME) by using adaptively expanded block based on frame difference for PRC. The proposed method is executed using an adaptively expanded block in order to get more accurate motion vector. By using frame difference, we can reduce complexity more significantly than conventional methods. We use quantitative analysis in order to evaluate experimental results. The results show that the proposed method has better performance and lower complexity than conventional methods.