• Journal of Korea Port Economic Association
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• v.36 no.2
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• pp.109-124
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• 2020

Using panel data on freight rates and ship prices in the dry freighter market from January 2015 to December 2019, this study investigates the characteristics of shipping industry fluctuations. The analysis aims at two aspects of academic contribution. First, this study analyzes the relationship between shipping indicators and ship price based on separate dry-bulk ships, while the previous research considered the overall shipping index and weighted average ship prices. Second, the VAR model for the causality test is extended to a heterogeneous mixed panel model capable of limiting coefficients. There is a peak estimated by removing the cross-correlation problem, which is mainly raised in panel data analysis, using bootstrap estimation and solving the problem of information loss due to differences in non-stationary data. An empirical investigation of the causal relationship between economic fluctuations and ship price shows that the effect on the ship price from the freight is significant at the 1% level. This implies that there is a one-way relationship with demand in the shipping industry rather than a bilateral relationship.

• Korean Journal of Digital Imaging in Medicine
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• v.9 no.2
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• pp.31-38
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• 2007

To evaluate the accuracy and extent in the localization of cerebral motor coutex activation using a gradient- echo echo planar imaging(GE-EPI) compared to spin-echo echo planar iimaging(SE-EPI) on 3T MR imaging. Functional MR imaging of cerebral motor cortex activation was examined in GE-EPI and SE-EPI in five healthy male volunteers. A right finger movement was accomplished with a paradigm of 6 task and rest, periods and the cross-correlation was used for a statistical mapping algorithm. We evaluated any sorts of differenced of the time seried and the signal intensity changes between the rest and task periods obtained with two technoques. The qualitative analysis was distributed with activation sites of large veins and small veins by using two techniques and was found that both the techniques were clinically uesful for delineating large veins and small veins in fMRL Signal intensity charge of the rest and activation periods provided simmilar activations in both methods(GE-EPI : 0.93$\pm$0.11, SE-EPI : 0.80$\pm$.015) but the signal intensity in GE-EPI(133.95$\pm$15.76) was larger than in SE-EPI(74.5$\pm$18.90). The average SNRs of EPI raw data were higher at SMA in SE-EPI(48.54$\pm$12.37) than GE-EPI(41.4$\pm$12.54) and at M1 in SE-EPI(43.24$\pm$11.77) than GE-EPI(38.27$\pm$6.53). The localization of activation voxels of the GE-EPI showed a larger vein but the SE-EPI generally showed small vein. Then the analysis results of the two techniques were used for a statistacal paired student t-test. SE-EPI was found clinically useful for localizing the cerebral moter cortex cativation on 3.0T, but showed a little different activation patterns comparad to GE-EPI. In conclusion, SE-EPI may be feasible and can detect true cortical activation from capillaries and GE-EPI can obtain the large veins in the motor cortex activation on 3T MR imaging.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.sup3
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• pp.263-268
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• 2016

Cervical cancer is the fourth common cancer among women worldwide. Pap smear screening has resulted in deceasing incidence of cervical cancer in developed countries but low uptake of Pap smear screening among women in developing countries is still a public health challenge. The aim of this cross-sectional study was to assess the relationship between self-efficacy and timely uptake of Pap smear among Iranian women. A total of 580 married women referred to primary health care centers covered administratively by Shahid Beheshti University of Medical Sciences in Tehran were administered a questionnaire by trained staff. Data were analyzed with SPSS (version 16) software, using univariate and multivariate logistic regression. The mean age for participants was $33.1{\pm}8.8years$. There was a significant association between self-efficacy and Pap smear screening (P<0.01). There was also a positive correlation between duration of marriage and husband's education with Pap smear uptake (P<0.01). In univariate analysis, there was a significant association between Pap smear uptake and level of selfefficacy (OR = 15.3 for intermediate and OR=7.4 for good level), duration of marriage (OR = 5.7 for 5-14 years and OR=10.4 for more than 15), age (OR =2.7 for 27-34 years and OR=7.4 for more than 35 years) and husband education level (OR=2.3 for more than 12 years of education). In multivariate analysis, significant associations persisted between Pap smear uptake and self-efficacy (OR = 23.8; 95% CI: 8.7, 65.5), duration of marriage (OR = 5.9; 95% CI: 2.8, 12.2), age (OR = 3.9; 95% CI: 1.2, 12.9) and husband's education (OR = 2.5; 95% CI: 2.0, 10.3). Efforts are needed to increase women's knowledge about cervical cancer and improve their self-efficacy and perceptions of the Pap smear screening in order to reduce cervical cancer incidence and mortality rates.

• Journal of Hospice and Palliative Care
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• v.15 no.4
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• pp.205-211
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• 2012

Purpose: This study was performed to identify the level of stress perceived by nurses who attend dying patients in the cancer care unit; their understanding regarding end-of-life care and related training needs. Methods: A cross-sectional descriptive study was conducted with 151 nurses stationed at the cancer care units of four general hospitals located in Seoul and Gyeonggi province in Korea. Data were collected using self-reported questionnaires and the response rate was 96%. The data were analyzed using t-test, ANOVA and Pearson's correlation analysis. SPSS 12.0 was used for data analysis. Results: Nurses experienced a high level of stress in the end-of-life care settings. Their understanding of end-of-life care was above the mid-point of the scale while their training needs for end-of-life care was relatively high. The more experienced the nurses were, the more stressed they were, particularly due to excessive workload. Nurses who served longer in the cancer unit tended to show greater needs for end-of-life care training. Conclusion: This study found nurses perform end-of-life care with a high level of stress but with insufficient understanding, and thus, showed great needs for related training. Such findings can be useful to develop an end-of-life care training program for nurses.

• Journal of Korean Clinical Nursing Research
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• v.23 no.1
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• pp.9-19
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• 2017

Purpose: This study aimed to identify multidimensional factors influencing burnout in intensive care unit(ICU) nurses. Methods: A descriptive cross-sectional design was used. Data were collected during February 2016 from a convenience sample of 222 tertiary hospital ICU nurses and analyzed using t-test, ANOVA, correlation analysis, and multiple regression analysis. Results: Burnout correlated positively with compassion fatigue (CF)(r=.37, p<.001), and negatively with compassion satisfaction (CS)(r=-.66, p<.001). The regression model explained 57% of the variance in burnout. For individual characteristics in the model, perceived health status (${\beta}=-.27$, p<.001) and gender (${\beta}=.14$, p=.028) were the most influential factors for ICU nurses' burnout. In the model with added work-related characteristics, nursing environment (${\beta}=-.22$, p=.001), perceived health status (${\beta}= -.20$, p=.001), and satisfaction with department (${\beta}=-.19$, p=.007) were the most influential factors. Finally, for the model with psychological characteristics added, CS (${\beta}=-.56$, p<.001) and CF (${\beta}=.35$, p<.001) were the most influential factors. Conclusion: Results reveal that most ICU nurses have a moderate level of CF and a moderate to high level of CS and burnout, and that individual, work-related and psychological factors are relevant in ICU nurses' burnout. Programs or interventions to reduce burnout should be developed taking into account these multidimensional factors.

• Food Science and Preservation
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• v.24 no.1
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• pp.145-152
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• 2017

In this study, near infrared (NIR) spectroscopy known as a non-destructive analysis technique was applied to investigate peptide cleavage and consequent release of amino acids in soybean lumps as affected by its moisture content and incubation time during fermentation at 25 for 3 weeks. The NIR spectra of the soybean lump semi-dried and soaked in saline water showed that absorption intensity around 1,400 nm originating from hydrogen bonds of water decreased and absorption band shifted to 1,430 nm as moisture content decreased during incubation at 25 for 3 weeks. In addition, absorption around 2,050 nm which was assigned to amino groups increased as incubation time increased. NIR spectra data from 1,000 to 2,250 nm showed higher accuracy in the discriminant analysis between outside and inside parts of fermented soybean lumps than visible spectra result. NIR spectroscopy for the amino acid and moisture contents in traditional fermented soybean lumps showed relatively good accuracy with the multiple correlation coefficient ($R^2$) of 0.91 and 0.81, respectively, and root mean square error of cross validation (RMSECv) of 0.23 and 0.83%, respectively, in partial least square regression (PLSR). These results indicate that NIR spectral observations could be applicable to control the fermentation process for preparation of soybean products.

• Journal of Energy Engineering
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• v.17 no.2
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• pp.116-123
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• 2008

In order to study the heat transfer, effectiveness and pressure drop of an internal heat exchanger (IHX) for $CO_2$, heat pump under heating condition, the experiment and numerical analysis were performed. Four kinds of IHXs were used. The section-by-section method and Hardy-Cross method were used for the numerical analysis. The effects of IHX on the flow rate of refrigerant, the IHX length, the operating condition of a gas-cooler and an evaporator and the type of IHXs were investigated. With increasing the flow rate, the heat transfer rate increased about 25%. The heat transfer of the micro-channel tube was larger about 100% than that of the coaxial tube. With increasing the IHX length, the heat transfer rate decreased. The low-side pressure drop was larger compared with that of the high-side. And the pressure drop of the microchannel tube was larger about 100% than that of the coaxial tube. With increasing the high-side temperature and decreasing the low-side temperature, the heat transfer rate increased about 3%. From this study, we can see that new correlation on $CO_2$ heat transfer characteristics and tube type is necessary.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1500-1506
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• 2015

The headcut erosion at the confluence section of a mainstream and tributary can migrate up the tributary streams, and rapid degradation can threaten the stability of hydraulic structures installed in the channel. Therefore, quantitative analysis for the development and mechanism of headcut erosion is needed to prevent damage due to the headcut. In this study, hydraulic experiments for headcut erosion in the channel with noncohesive materials were performed and the knickpoint movement and final bed slope change were analyzed based on the different hydraulic conditions. As a result, the knickpoint movement was 1.5 times faster when the difference in velocity between the upstream and downstream sections was 2.5 times greater and the central part of the cross-section was eroded and collapsed earlier than the left and right sides. The movement length of headcut erosion was longer and the final bed slope was milder as the velocity difference between the upstream and downstream sections was increased. This study showed that a correlation between the knickpoint movement and bed slope change by headcut erosion and the water level difference of upstream and downstream sections was not constant compared to the velocity difference.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4349-4358
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• 2013

This study aimed to examine the relation between subjective oral hygiene status of the elderly and oral health impact profile and to present it as basic data for the improvement of quality of life and oral care. The study subjects were 231 elderly people aged 65 and over. This study measured the oral health behavior and subjective oral hygiene status based on cross analysis by calculating the median of OHIP-14 to divide the above-median group into a subgroup and the below-median group into a superordinate group. Correlation and regression analyses were performed to examine the effects on the oral health impact profile. The oral health impact profile according to oral health behaviors was not significant. The oral health impact profile based on the subjective oral hygiene states is currently affected by oral hygiene status, masticatory problems, toothache, xerostomia and halitosis. As a result of regression analysis to confirm the effect on the oral health impact profile, much experience of masticatory problems, toothache, xerostomia and gum diseases is the most influential. This shows that the subjective oral hygiene status is not healthy as the oral health impact profile is high. It is considered necessary to establish an oral health promotion program to improve the quality of life of the elderly and active oral care methods in the future.

• Journal of Veterinary Clinics
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• v.34 no.2
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• pp.140-145
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• 2017

The goal of this study was to investigate risk factors associated with porcine reproductive and respiratory syndrome (PRRS) in pig farms in the Republic of Korea using logistic regression and a multilevel model. A cross-sectional study was applied to 305 pig farms with a questionnaire-based interview by veterinarians between March 2014 and February 2015. The questionnaire comprised eight categories: proximity to neighbors, disinfection, visitors, vehicles, insecticides, wild animals, gilts, and feeding. In total, 61 questions in eight categories related to pig farm biosecurity were investigated. Farms were classified as PRRS stable or unstable based on the results of an antibody test and PCR. For univariate analysis, keeping production records with computers (OR = 0.283, 95% CI = 0.056 - 1.425), accredited farm with no use of antibiotics (OR = 0.412, 95% CI = 0.134 - 1.269), reviewing health record of semen prior to purchasing (OR = 0.492, 95% CI = 0.152 - 1.589), complete isolation of runt pigs (OR = 0.264, 95% CI = 0.084 - 0.829), compulsory registering for visitors (OR = 0.424, 95% CI = 0.111 - 1.612), keeping records of insecticide history (OR = 0.406, 95% CI = 0.089 - 1.846), routine on-farm monitoring by veterinarians (OR = 0.314, 95% CI = 0.069 - 1.423), and use of on-farm checklist for biosecurity monitoring (OR = 0.313, 95% CI = 0.063 - 1.553) were found to decrease the probability of PRRS infection. Multivariate and multilevel analysis revealed only two factors, complete isolation of runt pigs (OR = 0.165, 95% CI = 0.045 - 0.602 and OR = 0.208, 95% CI = 0.055 - 0.782) and compulsory registering for visitors (OR = 0.106, 95% CI = 0.017 - 0.655 and OR = 0.119, 95% CI = 0.017 - 0.809) were found to decrease the probability of PRRS infection. The intracluster correlation coefficient of a province for multilevel model was 0.05. The results of this study might facilitate biosecurity measures for individual farms to reduce the probability of PRRS infection.