• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.5
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• pp.397-407
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• 2004

It is well known that some key parameters, such as evaporating temperature, refrigerant mass flow rate, face velocity and inlet air temperature, have significant influence on the evaporator performance. However performance studies related to a humid environment have been very scarce. It is demonstrated that the refrigerant mass flow rate, heat flux, water condensing rate and air outlet temperature of the evaporator significantly increase with air inlet relative humidity. As the air inlet relative humidity increases, the latent and total heat transfer rates increase, but the sensible heat transfer rate decreases. The purpose of this study is to provide experimental data on the effect of air inlet relative humidity on the air and refrigerant side pressure drop characteristics for a slit fin-tube heat exchanger. Experiments were carried out under the conditions of inlet refrigerant saturation temperature of 7 $^{\circ}C$ and mass flux varied from 150 to 250 kg/$m^2$s. The condition of air was dry bulb temperature of 27$^{\circ}C$, air Velocity Varied from 0.38 to 1.6 m/s. Experiments Showed that air Velocity decreased 8.7% on 50% of relative humidity 40% of that at degree of superheat of 5$^{\circ}C$, which resulted that pressure drop of air and refrigerant was decreased 20.8 and 8.3% for 50% of relative humidity as compared to 40%, respectively.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.34.3-34.3
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• 2008

Relative navigation system is presented using measurements from a single-channel global positioning system (GPS) simulator. The objective of this study is to provide real-time relative navigation results as well as absolute navigation results for two formation flying satellites separated about 1km in low earth orbit. To improve the performance, more accurate dynamic model and modified relative measurement model are developed. This modified method prevents non-linearity of the measurement model from degrading precision by applying linearization about the states from absolute navigation algorithm not about a priori states. Furthermore, absolute states are obtained using ion-free GRAPHIC pseudo-ranges and precise relative states are provided using double differential carrier-phase data based on Extended Kalman Filter. The software-based simulation is performed and achieved meter-level precision for absolute navigation and millimeter-level precision for relative navigation. The absolute and relative accuracies at steady state are about 0.77m and 4mm respectively (3D, r.m.s.). In addition, Integer ambiguity algorithm (LAMBDA method) improves simulation performances.

• The Journal of Korean Institute for Practical Engineering Education
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• v.4 no.1
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• pp.7-12
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• 2012

There are two ways in general for evaluating the accomplishments used by the universities, one is relative evaluation, the other is absolute evaluation. Recently, Korean universities have had the problem with score inflation due to absolute evaluation. The advantage of relative evaluation compared with absolute evaluation is for us to distinguish one's academic accomplishments from others. However, relative evaluation would lead to over-competition. Through this paper, I tired to analyze how cooperative learning influences the academic accomplishments under relative evaluation. Cooperative learning in the relative evaluation of student accomplishments conducted were divided into three groups. And analyzed a result and following presented about the research which in necessary.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1358-1366
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• 2006

In order to study the effects of shell contents on the liquefaction resistance of the shelly sand, NGI cyclic simple shear tests were performed for the shelly sands with shell contents of 0%, 5%, 10%, 20% and 30% under the effective vertical stress of 50kPa, 100kPa and 150kPa for 40% and 55% of relative density, respectively. Cyclic simple shear test results showed that for the low effective vertical stress, liquefaction resistance increased rapidly with the increase of shell contents in both 40% and 55% relative density. On the other hand, for the high effective vertical stress, the liquefaction resistance increased slightly in 40% relative density whereas the resistance was almost same in 55% relative density. Liquefaction resistance decreased with increasing effective vertical stress for both 40% and 55% relative density. In the same effective vertical stress and shell contents, liquefaction resistance increased with the increase of relative density of sands.

• Journal of Sensor Science and Technology
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• v.29 no.4
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• pp.237-242
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• 2020

This paper deals with relative position estimation using a Kalman filter (KF) based on inertial sensors that have been widely used in various biomechanics-related outdoor applications. In previous studies, the relative position is determined using relative orientation and predetermined segment-to-joint (S2J) vectors, which are assumed to be constant. However, because body segments are influenced by soft tissue artifacts (STAs), including the deformation and sliding of the skin over the underlying bone structures, they are not constant, resulting in significant errors during relative position estimation. In this study, relative position estimation was performed using a KF, where the S2J vectors were adopted as time-varying states. The joint constraint and the variations of the S2J vectors were used to develop a measurement model of the proposed KF. Accordingly, the covariance matrix corresponding to the variations of the S2J vectors continuously changed within the ranges of the STA-causing flexion angles. The experimental results of the knee flexion tests showed that the proposed KF decreased the estimation errors in the longitudinal and lateral directions by 8.86 and 17.89 mm, respectively, compared with a conventional approach based on the application of constant S2J vectors.

• Journal of Preventive Medicine and Public Health
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• v.20 no.2 s.22
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• pp.255-260
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• 1987

The digital dust indicator (Sibata P-5), one of the direct·reading instruments was evaluated for the respirable dust in the underground coal mine environments. As a reference, respirable dust was determined using three cyclones and/or impactors. All the tests were performed on aerosol in twenty underground coal mines. The coefficients of mass-relative concentration were $0.067{\pm}0.054$ (Mean$\pm$Standard deviation) (range: 0.006-0.172). The relationship between relative concentration and temperature was not significant statistically. Also, the relationship of relative concentration and relative humidity was not significant. Mass concentration and relative concentration were $5.31{\pm}5.22mg/m^3$ and $162{\pm}163$ CPM ($Mean{\pm}Standard$ deviation) respectively. The range of mass concentration was $1.22-22.69mg/m^3$; relative concentration 16-628 CPM. The relationship of mass concentration and relative concentration was not significant in these ranges.

• Journal of Ocean Engineering and Technology
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• v.19 no.2 s.63
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• pp.53-59
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• 2005

The effect of pH on the corrosion characteristics in the dissimilar friction welded zone of IN713LC-SCM440 in the loaded torsional stress was studied. The corrosion experiment was performed for 120 hours on the specimens with five steps of pH. The surface corrosion pattern of the SCM440 area showed global corrosion and narrow pitting, which was caused by galvanic corrosion between friction welded IN713LC and SCM440, but corrosion did not proceeded from the IN713LC area. The average relative electrode potential gradually tends to decrease with the elapse of the immersion time in the acidity area. The average corrosion current also gradually tend to decrease The corrosion rate showed a larger value when the average relative electrode potential was higher and the average relative current was lower. The corrosion rate showed a larger value when the average relative electrode potential was higher in the acidity area, and it showed large when the average relative electrode potential was lower in the alkalinity area.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.5
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• pp.457-462
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• 2005

The aim of this study is to evaluate the relative signal intensity of TMJ retrodiscal tissue in T2-weighted MRI as diagnostic marker of temporomandibular disorder(TMD). 58 temporomandibular joints from 29 TMD patients (14 men & 15 women) were evaluated. The relative signal intensity of retrodiscal tissue in T2-weighted MRI was referenced to brain gray matter same size of the region of interest(ROI). The collected data was compared to disc positions (normal, anterior disc displacement with reduction, anterior disc displacement without reduction), the presence of joint effusion. The relative signal intensity of retrodiscal tissue was significantly increased when the disc was displaced without reduction. And the relative signal intensity of retrodiscal tissue was significantly increased when joint effusion was present. The results suggest that evaluating the relative signal intensity of TMJ retrodiscal tissue using a T2-weighted MRI is valuable as a non-invasive tool for diagnosing the procession of TMD.

• Journal of Korean Academy of Nursing Administration
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• v.22 no.4
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• pp.362-372
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• 2016

Purpose: The aim of this study was to investigate whether job satisfaction in clinical nurses was dependent on work intensity and whether physical discomfort mediated the relationships between these variables. Methods: Structural equation modeling was used with a sample of 253 clinical nurses from four general hospitals. In the model, absolute work intensity, relative work intensity, and flexibility were considered as exogenous variables and physical discomfort as a mediating variable. Data were collected using self-report measures such as the Labor Intensity Questionnaire, the Rating of Perceived Exertion, and the Index of Job Satisfaction. Results: The results of the structural equation modeling found that the higher scores on absolute and relative work intensity were positively associated with physical discomfort but only relative work intensity was significantly related to job satisfaction. Physical discomfort mediated the relationships between absolute work intensity and job satisfaction and between relative work intensity and job satisfaction. Among three kinds of work intensity, only relative work intensity had direct and indirect effects on job satisfaction. Conclusion: The findings suggest that increase in relative work intensity might play an important role in decreasing job satisfaction in clinical nurses and a reasonable reward system considering relative work intensity could be necessary.

• English Language & Literature Teaching
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• v.8 no.2
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• pp.131-150
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• 2003

The purpose of this paper is to provide two levels of conceptualization of a category such as an absolute category in semantic level and a relative category in pragmatic level on the basis of Aristotelian category theory and prototype category theory. I do not intend to criticize classical category theory and prototype category theory but to show that these two types of category are applied to the different world. Aristotelian categorization is an absolute category because it is based on the possible world called the meta-world and it has an absolute truth value. The members of an absolute category is presented as a set. There is a clear boundary between members and non-members because they are distinguished by the absolute criteria An absolute category is semantic conceptualization. This absolute category is changed into a relative category when it is applied in the real world. A relative category which corresponds to a prototype category is based on the real world called the object world and it has a relative truth value. Here individuals are categorized by the cognition and perception of human beings. A relative category is pragmatic conceptualization. In conclusion, while classical categories which are called absolute categories represent sentence meaning, prototype categories which are called relative categories represent utterance meaning.