• Industrial Engineering and Management Systems
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• v.13 no.2
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• pp.163-171
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• 2014

Under amazing increase in markets and certain demand on qualified service in the delivery system, global logistic optimization is becoming a keen interest to provide an essential infrastructure coping with modern competitive prospects. As a key technology for such deployment, we have been engaged in the practical studies on vehicle routing problem (VRP) in terms of Weber model, and developed a hybrid approach of meta-heuristic methods and the graph algorithm of minimum cost flow problem. This paper extends such idea to multi-depot VRP so that we can give a more general framework available for various real world applications including those in green or low carbon logistics. We show the developed procedure can handle various types of problem, i.e., delivery, direct pickup, and drop by pickup problems in a common framework. Numerical experiments have been carried out to validate the effectiveness of the proposed method. Moreover, to enhance usability of the method, Google Maps API is applied to retrieve real distance data and visualize the numerical result on the map.

• Journal of the Korean Institute of Landscape Architecture
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• v.21 no.4
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• pp.29-41
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• 1994

The purposes of this study are (a)to investigate the effect of follow-up on the increase of response rate;(b)to analyze the effect of follow-up on the statistics by predetermined response rates ; therefore, (c)to describe the importance of high response rate and to suggest methods in order to increase response rate in mail survey. Telephone directory of Seoul was utilized as a sampling frame, and modified Total Design Method(TDM) was applied to collect the data. The results are summarized as follows. 1. Final response rate was 76.5% by 2 follow-ups. 2. The first follow-up with telephone call had a significant effect on increase of response rate. As a result, follow-up by postcard in TDM could be omitted in this method. 3. The second follow-up by registered mail did not have a significant effect. Therefore, use of this procedure is depending upon such research situtations as importance of high response rate and cost available. 4. Follow-ups helped to make collected sample highly representative. 5. Most questionnaires were arrived on the first half of data collection period in each follow-up. 6. Most of questionnaires were collected for 10 weeks. Accumulated responses could be fitted by exponential and logistic curve, simultaneously. The fitted curve suggested that eventually limited number of questionnaires by arrived. So, if researchers want higher response rate, they have to conduct more follow-ups. 7. Statistics in the predetermined response rate were not changed significantly. But replications are needed to generalize this result.

• Physical Therapy Korea
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• v.31 no.1
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• pp.48-54
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• 2024

Background: Promoting patients' safe return home at discharge and reducing length of stay in hospital is key for Restorative Rehabilitation Institution (RMI). Objects: This study was designed to identify the factors influencing the return to home and length of stay among various factors. Methods: A total of 120 stroke patients (76 males and 44 females) who were hospitalized in an adult inpatient unit of a RMI for more than 2 months were retrospectively analyzed for this study (multivariate logistic regression analyses, p < 0.001). As predictor variables for assessing the return to home and length of stay, demographic data (sex, age, duration between onset and admission, length of stay, caregiver after discharge, occupation after discharge, reason for discharge, and household type after discharge) were collected. Additionally, following measurements were selectively collected from patient's medical records: scores of Mini-Mental State Examination Korean version (K-MMSE), modified Barthel Index Korean version (K-MBI), Berg Balance Scale and Functional Ambulation Category were obtained at admission and discharge. Results: The K-MMSE at admission and K-MBI at discharge were found to be the predictors of return to home. Additionally, K-MBI at admission influenced the length of stay. Conclusion: This study suggests cognitive functioning at admission and the level of activities of daily living at discharge predicted the return to home and length of stay.

• Tuberculosis and Respiratory Diseases
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• v.81 no.3
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• pp.247-255
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• 2018

Background: Patients with acute respiratory failure secondary to tuberculous destroyed lung (TDL) have a poor prognosis. The aim of the present retrospective study was to develop a mortality prediction model for TDL patients who require mechanical ventilation. Methods: Data from consecutive TDL patients who had received mechanical ventilation at a single university-affiliated tertiary care hospital in Korea were reviewed. Binary logistic regression was used to identify factors predicting intensive care unit (ICU) mortality. A TDL on mechanical Ventilation (TDL-Vent) score was calculated by assigning points to variables according to ${\beta}$ coefficient values. Results: Data from 125 patients were reviewed. A total of 36 patients (29%) died during ICU admission. On the basis of multivariate analysis, the following factors were included in the TDL-Vent score: age ${\geq}65$ years, vasopressor use, and arterial partial pressure of oxygen/fraction of inspired oxygen ratio <180. In a second regression model, a modified score was then calculated by adding brain natriuretic peptide. For TDL-Vent scores 0 to 3, the 60-day mortality rates were 11%, 27%, 30%, and 77%, respectively (p<0.001). For modified TDL-Vent scores 0 to ${\geq}3$, the 60-day mortality rates were 0%, 21%, 33%, and 57%, respectively (p=0.001). For both the TDL-Vent score and the modified TDL-Vent score, the areas under the receiver operating characteristic curve were larger than that of other illness severity scores. Conclusion: The TDL-Vent model identifies TDL patients on mechanical ventilation with a high risk of mortality. Prospective validation studies in larger cohorts are now warranted.

• Korean Journal of Veterinary Service
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• v.31 no.4
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• pp.497-504
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• 2008

A cross-sectional study was undertaken to report prevalence and to identify risk factors of subclinical mastitis of dairy cattle in Sylhet district of Bangladesh. Among 325 dairy farms of the district 12 farms(3.7%) were selected conveniently for this study. All the dairy cows of the 12 farms were selected for sample collection. Fresh milk samples from each of the selected dairy cows were collected aseptically in separate sterilized test tube as RF, RH, LF and LH quarter of the udder. Rapid modified White Side Test(WST) was used to detect subclinical mastitis(SCM). Results of WST and data derived from filled in questionnaire were entered in Microsoft Excel 2003 and transferred to $STATA^{(R)}$, version 8.0/Intercooled(Stata Corporation, Texas, USA, 2003). The overall prevalence of SCM and its distribution in different categories of variables in cow and their exact binomial 95% confidence intervals were calculated in $STATA^{(R)}$. Simple bivariable associations among independent variables were investigated by $x^2$ test in $STATA^{(R)}$. Multiple logistic regression analysis with backward elimination method was used to identify risk factors of SCM. To identify significant variation in quarter SCM, linear regression analysis was performed after arcsine transformation of the data. The overall prevalence of SCM found in this study is 54%. Dairy cows with teat lesions had significantly increased SCM(OR=12342, P value=0.000, 95% CI=762, 199798) than others without teat lesions. The Holstein Friesian X Jersey X Sahiwal breed has significantly decreased(OR=0.18, p=0.03, 95% CI 0.04, 0.85) SCM than other breeds. The prevalence of SCM found in this study is in agreement with others. The injury in the teat increases the probability of getting infected with microbes and thereby mastitis. If the prevalence of teat lesion can be decreased the probability of subclinical mastitis will also be decreased. The negatively associated Holstein Friesian X Jersey X Sahiwall breed may help in planning mastitis control program if this finding can be validated by a more powerful case-control or cohort study design.

• Journal of The Korean Society of Emergency Medicine
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• v.29 no.5
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• pp.449-454
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• 2018

Objective: The SAFARI score was introduced to assess the risk of convulsive seizure during admission for aneurysmal subarachnoid hemorrhage in 2017. This study was conducted to determine whether the SAFARI score derived from the afore-mentioned study could be applied to patients with aneurysmal subarachnoid hemorrhage in Korea. Methods: We conducted a retrospective study of patients who were diagnosed with aneurysmal subarachnoid hemorrhage from March 2013 to October 2017. Patients' age, sex, blood pressure, pulse rate, body temperature, Glasgow-Coma Scale, Hunt-Hess scale, modified Fisher grade, size of ruptured aneurysm, surgery type, transfusion, and SAFARI score were compared between the seizure and non-seizure groups. The area under the receiver operator characteristic curves was calculated to evaluate the predictive ability for seizure during admission. Logistic regression analysis was used to analyze predictive factors for seizure during admission. Results: A total of 220 patients were included. Ninety-seven (44.1%) were male and 123 (55.9%) were female. The mean age of the patients was 65.8 years old (range, 56-75). The area under the curve of the SAFARI score for predicting seizure was 0.813. The SAFARI score was the only significant predictor of seizure during admission, while other factors were not statistically significant upon logistic regression analysis. Conclusion: The SAFARI score could be used for predicting seizure during admission in patients with aneurysmal subarachnoid hemorrhage.

• Journal of Nutrition and Health
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• v.54 no.6
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• pp.631-643
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• 2021

Purpose: Frailty is a clinical syndrome in older adults, and adequate nutrition is a modifiable factor in preventing the condition. The current study aims to investigate the association between frailty and dietary intake in the Korean elderly. Methods: This cross-sectional study included data from the 2018 Korean National Health and Nutrition Examination Survey of 1,268 subjects (535 men and 733 women) aged 65 years or older. Frailty was defined as having more than three of the following 5 modified Fried frailty phenotype criteria: unintentional weight loss, exhaustion, walking difficulties, weakness, and low physical activity. Dietary intake was assessed by applying the one-day 24-hour dietary recall. The association between frailty and dietary intakes were analyzed by multiple logistic regression. Results: Totally, 9.7% men and 21.9% women were classified as the frail group. Increasing levels of frailty were proportional to a decreased mean nutrient adequacy ratio in both genders. Moreover, the total food intake was significantly low in the frail elderly. In male subjects, multiple logistic regression analyses after adjusting covariates showed that the odds ratio (OR) of frailty in the highest tertile of the consumption of fruits (OR [95% confidence interval, CI] = 0.34 [0.13-0.93], p-trend = 0.021) were significantly lower than values obtained in the lowest tertile. In females, the highest tertile of fish and shellfish intake showed a significantly lower OR for frailty (OR [95% CI] = 0.55 [0.30-0.99], p-trend = 0.045), as compared with the lowest tertile. Conclusion: The present study indicates that high intake of fruits for men, and fish and shellfish for women, are probably linked with lowering the risk of frailty in the elderly.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• v.26 no.2
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• pp.141-151
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• 2024

Objective: Double microcatheter technique (dMC) can be the alternative to Single microcatheter technique (sMC) for challenging cases, but there is lack of studies comparing dMC to sMC especifically for small ruptured aneurysms. Our objective was to compare the safety and efficacy of dMC to sMC in treating small (≤5 mm) and tiny (≤3 mm) ruptured aneurysms. Methods: This study focused on 91 out of 280 patients who had ruptured aneurysms and underwent either single or double microcatheter coil embolization. These patients were treated with either single or double microcatheter coil embolization. We divided the patients into two groups based on the procedural method and evaluated clinical features and outcomes. Subgroup analyses were conducted specifically for tiny aneurysms, comparing the two methods, and within the dMC group, we also examined whether the aneurysm was tiny or not. In addition, univariate logistic regression analysis was performed to assess the impact of coil packing density. Results: The mean values for most outcome measures in the dMC group were higher than those in the sMC group, but these differences did not reach statistical significance (coil packing density, 45.739% vs. 39.943%; procedural complication, 4.17% vs. 11.94%; recanalization, 8.3% vs. 10.45%; discharge discharge modified Rankin Scale (mRS), 1.83 vs. 1.97). The comparison between tiny aneurysms and other sizes within the dMC group did not reveal any significant differences in terms of worse outcomes or increased risk. The only factor that significantly influenced coil packing density in the univariate logistic regression analysis was the size of the aneurysm (OR 0.309, 95% CI 0.169-0.566, p=0.000). Conclusions: The dMC proved to be a safe and viable alternative to the sMC for treating small ruptured aneurysms in challenging cases.

• Korean Journal of Radiology
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• v.24 no.10
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• pp.1028-1037
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• 2023

Objective: To evaluate the computed tomography (CT) features for diagnosing metastatic cervical lymph nodes (LNs) in patients with differentiated thyroid cancer (DTC) and validate the CT-based risk stratification system suggested by the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) guidelines. Materials and Methods: A total of 463 LNs from 399 patients with DTC who underwent preoperative CT staging and ultrasound-guided fine-needle aspiration were included. The following CT features for each LN were evaluated: absence of hilum, cystic changes, calcification, strong enhancement, and heterogeneous enhancement. Multivariable logistic regression analysis was performed to identify independent CT features associated with metastatic LNs, and their diagnostic performances were evaluated. LNs were classified into probably benign, indeterminate, and suspicious categories according to the K-TIRADS and the modified LN classification proposed in our study. The diagnostic performance of both classification systems was compared using the exact McNemar and Kosinski tests. Results: The absence of hilum (odds ratio [OR], 4.859; 95% confidence interval [CI], 1.593-14.823; P = 0.005), strong enhancement (OR, 28.755; 95% CI, 12.719-65.007; P < 0.001), and cystic changes (OR, 46.157; 95% CI, 5.07-420.234; P = 0.001) were independently associated with metastatic LNs. All LNs showing calcification were diagnosed as metastases. Heterogeneous enhancement did not show a significant independent association with metastatic LNs. Strong enhancement, calcification, and cystic changes showed moderate to high specificity (70.1%-100%) and positive predictive value (PPV) (91.8%-100%). The absence of the hilum showed high sensitivity (97.8%) but low specificity (34.0%). The modified LN classification, which excluded heterogeneous enhancement from the K-TIRADS, demonstrated higher specificity (70.1% vs. 62.9%, P = 0.016) and PPV (92.5% vs. 90.9%, P = 0.011) than the K-TIRADS. Conclusion: Excluding heterogeneous enhancement as a suspicious feature resulted in a higher specificity and PPV for diagnosing metastatic LNs than the K-TIRADS. Our research results may provide a basis for revising the LN classification in future guidelines.

• Korean Journal of Adult Nursing
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• v.26 no.4
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• pp.393-402
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• 2014

Purpose: The aim of this study was to describe the risk of dysphagia among older adults in senior centers and to find the relationships between the risk of dysphagia and dysphagia-specific quality of life. Methods: The participants were 260 community-dwelling older adults, aged 65 years in two senior centers. Data were collected by self-report questionnaires or face to face interviews. The instruments were the modified dysphagia risk assessment scale for elderly and dysphagia-specific quality of life questionnaire. The data were analyzed using t-test, $x^2$-test, logistic regression, and pearson's correlation. Results: 162 older adults (62.3%) were classified as having the risk of dysphagia. Severe dry mouth (OR=15.677, CI=2.986~82.297), neurologic disease (OR=10.125, CI=1.092~93.899), gastritis (OR=5.731, CI=1.482~22.173), denture discomfort (OR=2.969, CI=1.016~8.677), teeth discomfort (OR=2.61, CI=1.311~5.196) were the significant factors predicting the risk of dysphagia. There is a significant correlation between the risk of dysphagia and dysphagia-specific quality of life. Conclusion: Dysphagia could be a major health problem among community dwelling older adults. It can affect the dysphagia-specific quality of life. Older adults having severe dry mouth, neurologic disease, or gastritis should receive dysphagia risk assessment and proper management on a regular basis. An effective nursing intervention needs to be developed for the older adults with risk factors of dysphagia.