• Journal of ILASS-Korea
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• v.27 no.2
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• pp.101-108
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• 2022

Performance and emissions with different diesel injection methods were analyzed in a natural gas-diesel, dual-fuel engine under low-load conditions. Natural gas was supplied to intake port during the intake stoke to form a natural gas-air premixed mixture for all methods. Diesel was injected directly into the cylinder during the compression stroke in three ways: early injections, late injections, and a combination of early and late injections. The early injections had the highest thermal efficiency among the three methods owing to its highest combustion efficiency. The wide dispersion of diesel before the combustion initiation also allowed superior emissions characteristics.

• ETRI Journal
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• v.45 no.6
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• pp.1007-1021
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• 2023

Stroke is the leading cause of permanent disability in adults, and it can cause permanent brain damage. According to the World Health Organization, 795 000 Americans experience a new or recurrent stroke each year. Early detection of medical disorders, for example, strokes, can minimize the disabling effects. Thus, in this paper, we consider various risk factors that contribute to the occurrence of stoke and machine learning algorithms, for example, the decision tree, random forest, and naive Bayes algorithms, on patient characteristics survey data to achieve high prediction accuracy. We also consider the semisupervised self-training technique to predict the risk of stroke. We then consider the near-miss undersampling technique, which can select only instances in larger classes with the smaller class instances. Experimental results demonstrate that the proposed method obtains an accuracy of approximately 98.83% at low cost, which is significantly higher and more reliable compared with the compared techniques.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.1
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• pp.38-49
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• 2015

Past study of tsunami heavily relied on the numerical modelling using 2D Boussinesq Eq. and Solitary wave. Lately, based on the fact that numerically simulated run up heights based on solitary wave are somewhat smaller than the measured one, Leading Depression N (LDN) Wave has been elaborated, which can account the advancement of a shore line before tsunami strikes a shore. Thereafter it is reported that more accurate simulation can be possible once LDN is deployed. On the other hand, there were numerous reports indicating that stable LDN wave can't be sustained in the hydraulic model test. These conflicts between the hydraulic model tests and numerical results have their roots on the assumption made in the derivation of Boussinesq type wave model such as that wave nonlinearity is equally balanced with wave dispersiveness. Hence, in the numerical simulation based on the Boussinesq type wave model, wave dispersiveness is inevitably underestimated, especially in deep water. Based on this rationale, we developed the modified methodology for the generation of stable LDN wave in the 3D numerical wave flume, and proceeded to numerically analyze the depression effect of Hybrid Breaker on the run up height due to tsunami using the Navier Stoke Equation. The verification of newly proposed wave model in this study was carried out using the run up height from the hydraulic model test. It was shown that Hybrid Breaker consisting of three water chamber and slope at its front can reduce 13% of run up height for H = 5m, and 10% of run up height for H = 6m.

• The Korean Journal of Rehabilitation Nursing
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• v.9 no.1
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• pp.15-24
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• 2006

Purpose: This study was to explore the cognitive function of Korean-Chinese stroke patient in China. Method: The study sample was 100 who were possible to communicate and agreed. The data were collected from one Brain's hospital at Yanji in China and by trained nurse from December 12, 2005 to April 28, 2006. The measurement tools were Digit span, Trail making, and MMSE-K. The data were analysed by SPSS Win 11.5 using frequency, t-test, ANOVA, and Pearson's correlation coefficients. Results: The mean score of DSF was 5.07, 3.42 of DSB, 161.37 of TMA, 229.28 of TMB, 22.64 of MMSE-K. There was a significant difference in DSF (F=6.35, p=.001), DSB (F=6.10, p=.001), TMA (F=3.53, p=.018), TMB (F=3.26, p=.025), MMSE-K score (F=12.97, p=.000) according to age, and DSF (F=6.67, p=.000), DSB (F=6.01, p=.000), TMA (F=5.82, p=.001), TMB (F=6.23, p=.001), and MMSE-K score (F=13.02, p=.000) according to educational level, and DSF (F=5.35, p=.006), DSB (F=3.16, p=.047), TMA (F=3.30, p=.041), TMB (F=3.42, p=.037), and MMSE-K score (F=4.95, p=.009) according to duration of disease, and DSB (F=3.54, p=.018), and MMSE-K (F=6.05, p=.001) according to frequencies of hospitalization. There was high correlation between DSF and DSB (r=.581, p=.000), TMA and TMB (r=.936, p=.000), MMSE-K and DSF (r=.579, p=.000), MMSE-K and DSB (r=.591, p=.000), DSF and TMA (r=.727, p=.000), and DSF and TMB (r=.721, p=.000). Conclusion: The cognitive evaluation score of Korean-Chinese stroke patients in China was in normal limit. The age, educational level, duration of disease and income were significant demographic characteristic affecting cognitive function. Further study need to compare the cognitive function of Korean-Chinese stoke patients in China and stoke patients in Korea.

• 재활복지
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• v.18 no.4
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• pp.221-235
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• 2014

Recently, the frequency of stroke disease is increased due to the rapid aging population, and is contributed to the major occurrence factors of the posteriori acquired disability. This study is about an postural change device for the control of supine posture which is an assisted equipment using in daily rehabilitation process for overcoming the disability by the aftereffects of the stoke disease. In this paper, the existing domestic and Japan postural appliances is examined and its comparison and categorization is performed according to its functions and purposes. Here, in order to control the supine posture state, the design method for advanced multi functional system is proposed, which is devised to have an unified mattress control operations of combining the bedsore prevention tube with the supine posture tilting tube. And also, in addition of an smart function, it is designed to enable to perform an RF functions such as the monitoring of the present device state, the alteration of the basic position and the control of alternative floating and supine posture. This system control hardware consists of three main parts : the sensor detection part, the motor driving /control part, and the system control part for bluetooth communication. In results, we confirmed that the system designed by this research is possible to make it practical as an advanced smart postural change device combined by IoT technology in the application field of the recent IT technology.

• Journal of Biomedical Engineering Research
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• v.2 no.2
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• pp.89-102
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• 1981

The recirculating flows which occur in the prosthetic heart valve have been known to cause several diseases in the human body. And the recent studies show that the shear stress at the wall of the artery is also very important factor in the formation of thrombus. And many studies knave been devoted in obtaining more information about the blood flow through the prosthetic heart valve. In this Paper, the steady axisymmetric flow through the Disc-Type Heart Valve is studied by using the numerical method. The geometry of the Disc-Type Heart Valve is simplified, and the flow is assumed to be steady axisymmetric flow. The vorticity transport equation derived from the Wavier-Stoke's equation is used as the governing equation, and the explicit finite difference method is used to obtain the steady state solution. The results for several Reynolds numbers show that the recirculating flow becomes large as the Remolds number increases. Furthermore, it can be shown that the magnitudes of the vorticity and the stresses are also increased with the Reynolds number, but there is only a little change in their configurations of distribution and in their positions of maximum values.

• Journal of muscle and joint health
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• v.19 no.2
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• pp.107-119
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• 2012

Purpose: This study was conducted to extract international classification of functioning, disability, and health (ICF) core sets for measuring functional status in acute stroke patients, and to evaluate clinical applicability of the core sets. Methods: A set of 22 ICF items on functional status in acute stroke patients were extracted from the Korean general ICF core sets and ICF core sets for stroke patients. The extracted ICF functional items were assessed at the time of admission and discharge among 100 stroke patients who were admitted in a university hospital. Results: Comparing to functional status at admission of acute stroke patients, the overall functional status at discharge was improved. However, functions on defecation, skin protection, and relationship with immediate family at the time of discharge were not significantly changed. Conclusion: The set of ICF functional items identified in this study may be reliable and valid to assess acute stoke patients' body functions, activities and participation and environmental factors in the holistic and comprehensive nursing context. Nursing interventions on bowel elimination and skin protection for acute stroke patients need to be developed.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.6
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• pp.24-32
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• 2004

The effects of guide vanes and tip clearances on the characteristics nf axial flow fans are investigated both computationally and experimentally. Performance test of fans carried out in full scale shows considerable effects of tip clearance between rotor tip and duct on the characteristics of fans. The tested results are compared with the computation based on the finite volume method to solve the Navier-Stoke equations with $textsc{k}$-$\varepsilon$ turbulence model. The comparison shows good agreements between experimental and computational results. In addition, the effects of shape of guide vanes are numerically studied. The results show that increased volume of separated region around the guide vane reduces the recovery of tangential component of kinetic energy in the wake, resulting in loss of efficiency

• Journal of Acupuncture Research
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• v.20 no.2
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• pp.161-172
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• 2003

Objective : This study was designed to investigate the relation between the angiotensin converting enzyme(ACE) gene polymorphism and stroke in the Korean population. Methods : This study was carried out on 58 stroke patients who were hospitalized in the department of acupuncture & moxibustion, college of Oriental Medicine, Kyung-Hee University and 61 healthy control subjects. Blood samples from all subjects were obtaind for DNA extration. The extracted DNA was amplified by polymerase chain reaction(PCR). PCR products were visualized by 2% agarose gel electrophoresis. Results : The sub-genotypes of ACE gene were II homozygotes, ID heterozygotes, DD homozygotes. While the distribution of ACE polymorphism in control subjects was 31%, 51%, 18%, the distribution of it in stoke patients was 33%, 52%, 16%(II, ID, DD). Thus, there was no significant different between the control and stroke groups. Conclusions : we conclude that there is no significant association between ACE gene polymorphism and storke in Korean papulation. However, the findings of this study need to be confirmed in large patients and further studies. Additional epidemiologicallly based studies of the effects and relationship between ACE or other genes and lifesyles with regard to stroke required.

• Journal of Korean Biological Nursing Science
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• v.16 no.1
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• pp.52-59
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• 2014

Purpose: The purpose of this study was to investigate antioxidant capacity and relating factors including gender, obesity, lifestyle factors, and nutrient intake in chronic stroke patients. Methods: A total of 188 chronic stroke patients who visited a medical center in Seoul participated in the study. A structured questionnaire was used to assess their clinical characteristics and lifestyles. Blood samples were collected for ferric reducing ability of plasma (FRAP) for antioxidant capacity. Dietary intake of the patients were obtained for 2 days by 24 hours recall method. Results: The mean FRAP was $392.0{\mu}mol/L$. According to the hierarchical multiple regression analysis, the factors related to high FRAP were male sex (p=.036), alcohol drinking (p=.013), and calorie intake deficiency (p=.005). Conclusion: We found that antioxidant capacity was related to lifestyle factors including alcohol drinking, and calorie intake in chronic stroke patients. A tailored strategy is needed to increase antioxidant capacity according to gender and lifestyles in the chronic phase of stoke patients.