• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.2
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• pp.64-79
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• 2023

This study reviewed the process of applying the Monte Carlo simulation technique to the traffic allocation problem of metropolitan subways. The analysis applied the assumption of a normal distribution in which the travel time information of the inter-station sample is the basis of the probit model. From this, the average and standard deviation are calculated by separating the traffic between stations. A plan was proposed to apply the simulation with the weights of the in-vehicle time of individual links and the walking and dispatch interval of transfer. Long-distance traffic with a low number of samples of 50 or fewer was evaluated as a way to analyze the characteristics of similar traffic. The research results were reviewed in two directions by applying them to the Seoul Metropolitan Subway Network. The travel time between single stations on the Seolleung-Seongsu route was verified by applying random sampling to the in-vehicle time and transfer time. The assumption of a normal distribution was accepted for sample sizes of more than 50 stations according to the inter-station traffic sample of the entire Seoul Metropolitan Subway. For long-distance traffic with samples numbering less than 50, the minimum distance between stations was 122Km. Therefore, it was judged that the sample deviation equality was achieved and the inter-station mean and standard deviation of the transport card data for stations at this distance could be applied.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.28 no.1
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• pp.41-50
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• 2023

Dissolved oxygen sensors have characteristics in which data drift occurs over time. Therefore, in-situ calibration of the dissolved oxygen sensor is essential to accurately measure the concentration of dissolved oxygen in seawater. In order to provide a method for in-situ calibration, appropriate number of samples for calibration, and laboratory calibration interval of the dissolved oxygen sensor, the dissolved oxygen sensor values were compared with the measured values by titration on a total of 133 samples from three different cruises in the Indian Ocean, Pacific Ocean, and East Sea over a period of about one year. As a result, it is preferable to calibrate the sensor value using the correlation of a straight line obtained by directly comparing the final concentration value given by the sensor and the measured value. For the accurate calibration, at least 30 samples must be used to enable in-situ calibration within an accuracy range of about 1%. In addition, it is recommended that a laboratory calibration should perform within 1 year for the membrane type dissolved oxygen sensor for CTD to achieve a performance of 70% or more.

• Journal of agriculture & life science
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• v.50 no.4
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• pp.59-71
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• 2016

The occurrence and growth of grass and sedge weed species were investigated in the transplanted rice fields that have different transplanting dates from Apr. 30 to Jun 19 with 10-day interval. The growth and yield of rice plant grown without weed control examined in each plot that has different transplanting dates. Both grass and sedge weeds showed greater plant numbers in the early transplanted plots(Apr. 30 and May 10) than late transplanted plots. Based on the occurring number and dry weight of weeds, the experimental plots were classified into two groups, early group and late group. Weed occurrence and growth were not dramatically different within a group even the occurrence was enhanced as delayed transplanting. Echinochloa spp. that was the most problematic weed showed higher dry weight in early-transplanted field until July, however, the greater dry weight was observed in the late-transplanted plots after August. Sedge weeds including Eleocharis kuroguwai and Scirpus juincoides showed persistently higher value of dry weight in early-transplanted plots than late plots over the experimental period. As the puddling was conducted earlier, emergences of grass and sedge weeds were occurred early and weed growth rate became greater. Therefore, growth and yield of rice that transplanted early decreased more strongly due to the strong suppression by grass and sedge weeds showing the enhanced weed growth rates in early-transplanted plots. Based on the weed growth rate, the adverse effects of grass weeds was maintained for longer period than sedge weeds that showed higher growth rates before heading date of rice plant.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.2
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• pp.93-102
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• 2023

Objectives: With the evolution of direct reading sensors, it is possible to monitor several substances through telecommunication. However, there are some limitations on the use of direct reading technologies in the Occupational Safety and Health Act in South Korea, which only applies to detector tubes, noise, heat, and carbon monoxides. The number of chemicals and their amount of use have been continuously increasing in South Korea. The Ministry of Employment and Labor (MoEL) has concerns about worker's health because exposure is only covered for about 1.2% of all distributed chemicals. Using a direct reading monitor with photoionization detectors (PID-DRMs), gases and vapors chemicals can be measured. Based on the data, business owners are able to create corrective strategies, provide better working routines, and select correct respiratory equipment. PID-DRMs are less expensive and easier to handle for an owner voluntarily controlling chemicals emitted in the workplace. However, there are several limitations on using these PID-DRMs to the degree that the MoEL has not been able to select a legal monitor. The aim of this study was to review previous studies related to PID-DRMs and identify the characterization and limitation on PID-DRMs. Methods: To search for related studies on PID-DRMs, key words were used including direct reading monitors/instruments and/or photoionization detectors. Through that, four domestic and 15 international studies were reviewed. Results: Studies on PID-DRMs were conducted by chamber (enclosed, dynamic, walk-in) and in the field (experimental environment, actual environment). The concentration of PID-DRMs and charcoal tubes were compared for a single substance or mixture, or within the PID-DRMs. There was a high correlation between the two concentrations, but it did not meet the accuracy criteria (95% confidence interval, within 25%) of the NIOSH technical report (2012). In addition, differences in measured values occurred according to environmental factors (temperature, humidity) and high concentration, and concentration values tended to be underestimated due to contamination of the sensor. As a way to improve the accuracy of PID concentration, it was proposed to use correction factors, charcoal tube-based correction factors, or to calibrate the PID-DRMs in the same environment as the workplace. Conclusions: PID-DRMs can likely be used by business owners for the purpose of voluntarily managing the workplace environment, and it is expected that it will be possible to use them as legal equipment if a PID sensor can be upgraded and the limitations of the sensor (temperature, humidity, high concentration evaluation, sensor pollution) can be overcome in the near future.

• Journal of Gastric Cancer
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• v.23 no.3
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• pp.499-508
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• 2023

Purpose: Despite scientific evidence regarding laparoscopic gastrectomy (LG) for advanced gastric cancer treatment, its application in patients receiving neoadjuvant chemotherapy remains uncertain. Materials and Methods: We used the 2019 Korean Gastric Cancer Association nationwide survey database to extract data from 489 patients with primary gastric cancer who received neoadjuvant chemotherapy. After propensity score matching analysis, we compared the surgical outcomes of 97 patients who underwent LG and 97 patients who underwent open gastrectomy (OG). We investigated the risk factors for postoperative complications using multivariate analysis. Results: The operative time was significantly shorter in the OG group. Patients in the LG group had significantly less blood loss than those in the OG group. Hospital stay and overall postoperative complications were similar between the two groups. The incidence of Clavien-Dindo grade ≥3 complications in the LG group was comparable with that in the OG group (1.03% vs. 4.12%, P=0.215). No statistically significant difference was observed in the number of harvested lymph nodes between the two groups (38.60 vs. 35.79, P=0.182). Multivariate analysis identified body mass index (odds ratio [OR], 1.824; 95% confidence interval [CI], 1.029-3.234; P=0.040) and extent of resection (OR, 3.154; 95% CI, 1.084-9.174; P=0.035) as independent risk factors for overall postoperative complications. Conclusions: Using a large nationwide multicenter survey database, we demonstrated that LG and OG had comparable short-term outcomes in patients with gastric cancer who received neoadjuvant chemotherapy.

• Journal of Korean Medicine Rehabilitation
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• v.33 no.3
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• pp.149-160
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• 2023

Objectives This study is for reporting current status and strategies of thread embedding acupuncture (TEA) in temporomandibular joint disorder (TMD) using web-based survey. Methods Survey was conducted online via E-mail among Korean medicine doctors registered with the Association of Korean Medicine. The questionnaire is developed by Korean medicine doctor in Kyung Hee University Hospital at Gangdong. The survey consisted mainly of multiple-choice questions on the current status and strategies of TEA for TMD. Results Total of 427 doctors responded. TEA was mostly used for 'Cosmetic purpose and others' with 287 respondents (67.2%), and 102 respondents (23.9%) having experience with TEA for TMD. The most common purpose for TEA for TMD was 'Improving muscle contraction and tension' with 290 respondents (67.9%). The average interval was reported 2.12 weeks, and the most common response for the number of treatments was five sessions with 127 respondents (29.7%). The most common criterion for determining the treatment site was based on anatomical structure, accounting for 92.7%. The most effective anatomical structure was the 'Masseter muscle' with 83.1%, followed by the 'Temporal muscle' with 51.8%. TEA direction for TMD was dominant in 'affected side' for all muscles. Conclusions Through a survey, we can investigate clinical usage of TEA for TMD. This study can be helpful in creating standardized criteria for TEA on TMD in the future.

• 한국체육학회지인문사회과학편
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• v.57 no.2
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• pp.509-518
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• 2018

The purpose of this study was to examine the association between resting heart rate (RHR) and the prevalence of colorectal cancer in Korean adults. A cross sectional analysis was performed using the Korea National Health and Nutrition Examination Survey (2005 to 2014). Total number of subjects were 10,564 adults aged over 19 years. The results showed that individuals in the highest quartile of RHR had a significantly higher prevalence of colorectal cancer (Odds ratio (OR) 2.27, 95% confidence interval (CI): 1.34-3.85 to OR 3.00, 95%CI: 1.30-6.92) compared to those in the lowest quartile. Futhermore, every 10 beat per minutes (bpm) increase in RHR was associated with 27% (95%CI: 1.03-1.58) increased prevalence of colorectal cancer. In addition, after stratification by age and gender, the result showed that older people (>65 years) in the highest quartile of RHR had a significantly higher prevalence of colorectal cancer compared to those who were in the lowest quartile of RHR. (male OR 3.19, 95%CI: 1.10-9.24 to OR 3.38, 95%CI: 1.18-9.73; female OR 2.90, 95%CI: 1.13-7.42 to OR 5.59, 95%CI: 1.20-25.99). In this study, we examined the feasibility of RHR as a predictive factor of colorectal cancer prevalence. Moreover, we found that RHR was closely related to the prevalence of colorectal cancer in the age of over 65 years.

• Journal of Korean Dental Science
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• v.16 no.2
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• pp.128-148
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• 2023

Dementia is an umbrella term that describes the loss of thinking, memory, attention, logical reasoning, and other mental abilities to the extent that it interferes with the activities of daily living. More than 50 million individuals worldwide live with dementia, which is expected to increase to 131 million by 2050. Recent research has shown that poor oral health increases the risk of dementia, while oral health declines with cognitive decline. In this narrative review, the literature was based on the "hypothesis" that dementia and oral health have a close relationship, and appropriate oral health and occlusal rehabilitation treatment can improve the quality of life of patients with dementia and prevent progression. We conducted a literature search in PubMed and Google Scholar databases, using the search terms "dementia," "major neurocognitive disorder," "dentition," "occlusion," "tooth loss," "dental prosthesis," "dental implant," and "occlusal rehabilitation" in the title field over the past 30 years. A total of 131 studies that scientifically addressed dementia, oral health, and/or oral rehabilitation were included. In a meta-analysis, the random effect model demonstrated significant tooth loss increasing the dementia risk 3.64-fold (pooled odds ratio=3.64, 95% confidence interval [2.50~5.32], P-value=0.0348). Tooth loss can be an important indicator of cognitive function decline. As the number of missing teeth increases, the risk of dementia increases. Loss of teeth can lead to a decrease in the ascending information to the brain and reduced masticatory ability, cerebral blood flow, and psychological atrophy. Oral microbiome dysbiosis and migration of key bacterial species to the brain can also cause dementia. Additionally, inflammation in the oral cavity affects the inflammatory response of the brain and the complete body. Conversely, proper oral hygiene management, the placement of dental implants or prostheses to replace lost teeth, and the restoration of masticatory function can inhibit symptom progression in patients with dementia. Therefore, improving oral health can prevent dementia progression and improve the quality of life of patients.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.3
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• pp.236-244
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• 2023

The purpose of this study was to examine the economic feasibility of providing services according to the nationwide expansion of early warning services. The net present value method, one of the cost-benefit analysis methods, was applied to the analysis. As a benefit item that constituted the net present value, the damage reduction amount using crop insurance data and the willingness to pay for the use of early warning services were used. The cost items included system construction and maintenance costs, and text transmission costs. As a result of the analysis, it was found that the nationwide expansion of early warning services had economic feasibility, and its economic effect varied depending on the level of text message use (10 % to 40 %, 10 %p interval) of participating farmers. In the future, the economic effect of early warning services is expected to increase further due to the increase in the number of farmers participating in early warning services and the increase in crop damage caused by climate change. It is necessary to further enhance the economic effect of early warning services by actively utilizing information delivery means through apps or the web as well as text messages.

• Pediatric Infection and Vaccine
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• v.31 no.1
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• pp.55-63
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• 2024

Purpose: A 2-dose varicella vaccination strategy has been introduced in many countries worldwide, aiming to increase vaccine effectiveness (VE) against varicella infection. In this network meta-analysis, we aimed to provide a comprehensive evaluation and an overall estimated effect of varicella vaccination strategies, via a Bayesian model. Methods: For each eligible study, we collected trial characteristics, such as: 1-dose vs. 2-dose, demographic characteristics, and outcomes of interest. For studies involving different doses, we aggregated the data for the same number of doses delivered into one arm. The preventive effect of 1-dose vs. 2-dose of varicella vaccine were evaluated in terms of the odds ratio (OR) and corresponding equal-tailed 95% confidence interval (95% CI). Results: A total of 903 studies were retrieved during our literature search, and 25 interventional or observational studies were selected for the Bayesian network meta-analysis. A total of 49,265 observed individuals were included in this network meta-analysis. Compared to the 0-dose control group, the OR of all varicella infections were 0.087 (95% CI, 0.046-0.164) and 0.310 (95% CI, 0.198-0.484) for 2-doses and one-dose, respectively, which corresponded to VE of 69.0% (95% CI, 51.6-81.2) and VE of 91.3% (95% CI, 83.6-95.4) for 1- and 2-doses, respectively. Conclusions: A 2-dose vaccine strategy was able to significantly reduce varicella burden. The effectiveness of 2-dose vaccination on reducing the risk of infection was demonstrated by sound statistical evidence, which highlights the public health need for a 2-dose vaccine recommendation.