• The Journal of the Korea Contents Association
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• v.22 no.6
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• pp.69-77
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• 2022

Physical experiment through MBL has been used in many schools for a long time since students can check the experiment results immediately and conduct the experiment easily. However, conducting the experiment, not knowing the principle of the device or simply concentrating on the derived data has been raised as the problem of MBL experiment. To supplement this problem, this study measured the acceleration of gravity with the picket fence method, which is often used in MBL experiment, utilizing Arduino, calculated the error rate through a comparison to the actual acceleration of gravity and discussed the educational application of the experiment to measure it. As a result of the experiment, the error rate between the acceleration of gravity calculated by the experiment and the actual acceleration of gravity was about 1%, so it turned out that relatively accurate measurements were possible. Also, the sample mean of the experimental value was included in the confidence interval of 95%, so it could be concluded that it was a significant experiment. In addition, this study showed the possibility of the educational application of the experiment to measure it through the following: It can supplement the structural disadvantages of MBL; it can consider the interaction between Physics and Math; it is possible to converge with information course in STEAM education; and it is inexpensive to be equipped with the equipment. Hopefully, the physical experiment utilizing Arduino will further be revitalized in science gifted education based on this study.

• Resources Recycling
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• v.31 no.4
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• pp.34-39
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• 2022

In this study, effects of ultrasonic energy on the cementation reaction and copper recovery rate were investigated for different types of iron samples, such as plate, chip, and powder, for recovering copper from waste etchant, which contained ~3.5% copper. The cementation reaction using the ultrasonic energy was more effective than the simple stirring reaction, with the former exhibiting a high copper recovery rate than the latter for the same time interval. When cementation was performed for 25 min with ultrasonic treatment, rather than simple stirring, the copper recovery rate of the plate, chip, and powder improved from 7.0% to 12.0%, 14.0% to 46.1%, and 41.9% to 77.2%, respectively. Therefore, the use of ultrasonic energy could detach the copper recovered by the cementation reaction from the surface of the iron samples, thereby increasing the copper recovery rate. Owing to the use of ultrasonic energy, the copper recovery rate increased by 2-6 times, and the recovered copper exhibited a decreased particle size compared to that obtained via simple stirring.

• Journal of Digestive Cancer Reports
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• v.8 no.2
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• pp.81-90
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• 2020

We performed a comprehensive meta-analysis on whether Helicobacter pylori (H. pylori) eradication can prevent gastric cancer in individuals with precancerous lesions (chronic atrophic gastritis, intestinal metaplasia, and dysplasia). The studies evaluating the effect of H. pylori eradication on gastric cancer were searched from PubMed, KoreaMed, EMBASE, and Cochrane Library. Subgroup analyses by precancerous lesions, regions and follow-up time were performed. Six randomized clinical trials were included. In the overall population, H. pylori eradication significantly decreased the risk of gastric cancer (risk ratio [RR]=0.56; 95% confidence interval [CI]: 0.41-0.77, p<0.01). Eradication therapy significantly reduced the risk of gastric cancer in Asian and group who followed up more than 10 years (RR=0.51; 95% CI: 0.35-0.73, p<0.01; I²=0%, p=0.46). However, subgroup analysis according to the precancerous lesions did not show any significant results (p>0.05). In the general population especially in Asian population, H. pylori eradication can reduce the risk of gastric cancer. The effect of the eradication treatment is remarkable upon the long-term follow-up. In contrast, there is insufficient evidence whether the eradication should be recommended for the individuals with precancerous lesions.

• Journal of the Korean Regional Science Association
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• v.38 no.2
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• pp.59-72
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• 2022

In line with increasing interest of climate change and pedestrian rights, the city of Seoul has been implementing car-free pedestrian street policies. The government and the private sector agreed to introduce carfree streets, expecting to increase the urban vibrancy and attract customers in the streets. However, studies that empirically analyze the effects of the policy are insufficient, and there are no studies that reevaluate the car-free pedestrian street policy after the COVID-19 outbreak. Therefore, this study evaluates the car-free pedestrian street policy at the commercial street, the Jongno 52-gil, using the synthetic control method. As a result of the analysis, it was found that the car-free pedestrian street policy was valid for enhancing urban vibrancy. Also, it was found that proper time interval is required to assess the policy since the peak increase of policy was observed in 3 months after the policy implementation. However, less than a year, the increase of the de facto population density on the Jongno 52-gil was revealed to be insignificant. In addition, the Jongno 52-gil was more vulnerable in the decrease of the de facto population density in the COVID-19 period than the synthetic control region. The results of this study suggest that long-term population inflow measures and flexible counterplan to contagious diseases are necessary in the car-free pedestrian street policy.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.3
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• pp.39-47
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• 2022

In this paper, we proposed a thickness measurement method of concrete slab using GPR, and the verification of the suggested algorithm was carried out through real-scale experiment. The thickness measurement algorithm developed in this study is to set the relative dielectric constant based on the unique shape of parabola, and time series data can be converted to thickness information. GPR scanning were conducted in four types of slab structure for noise reduction, including finishing mortar, autoclaved lightweight concrete, and noise damping layer. The thickness obtained by GPR was compared with Boring data, and the average error was 1.95 mm. In order to investigate the effect of finishing materials on the slab, additional three types of finishing materials were placed, and the following average error was 1.70 mm. In addition, sampling interval from device, the effect of radius on the shape of parabola, and Boring error were comprehensively discussed. Based on the experimental verification, GPR scanning and the suggested algorithm have a great potential that they can be applied to the thickness measurement of finishing mortar from concrete slab with high accuracy.

• Nutrition Research and Practice
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• v.16 no.5
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• pp.604-615
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• 2022

BACKGROUND/OBJECTIVES: This study aimed to investigate cancer-specific survival (CSS) and associated risk factors in elderly gastric cancer (EGC) patients. SUBJECTS/METHODS: EGC patients (≥ 70 yrs) who underwent curative gastrectomy between January 2013 and December 2017 at our hospital were included. Clinicopathologic characteristics and survival data were collected. Receiver operating characteristic (ROC) analysis was used to extract the best cutoff point for body mass index (BMI). A Cox proportional hazards model was used to determine the risk factors for CSS. RESULTS: In total, 290 EGC patients were included, with a median age of 74.7 yrs. The median follow-up time was 31 (1-77) mon. The postoperative 1-yr, 3-yr and 5-yr CSS rates were 93.7%, 75.9% and 65.1%, respectively. Univariate analysis revealed risk factors for CSS, including age (hazard ratio [HR] = 1.08; 95% confidence interval [CI], 1.01-1.15), intensive care unit (ICU) admission (HR = 1.73; 95% CI, 1.08-2.79), nutritional risk screening (NRS 2002) score ≥ 5 (HR = 2.33; 95% CI, 1.49-3.75), and preoperative prognostic nutrition index score < 45 (HR = 2.06; 95% CI, 1.27-3.33). The ROC curve showed that the best BMI cutoff value was 20.6 kg/m². Multivariate analysis indicated that a BMI ≤ 20.6 kg/m² (HR = 2.30; 95% CI, 1.36-3.87), ICU admission (HR = 1.97; 95% CI, 1.17-3.30) and TNM stage (stage II: HR = 5.56; 95% CI, 1.59-19.43; stage III: HR = 16.20; 95% CI, 4.99-52.59) were significantly associated with CSS. CONCLUSIONS: Low BMI (≤ 20.6 kg/m²), ICU admission and advanced pathological TNM stages (II and III) are independent risk factors for CSS in EGC patients after curative gastrectomy. Nutrition support, better perioperative management and early diagnosis would be helpful for better survival.

• Journal of Internet Computing and Services
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• v.24 no.1
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• pp.61-69
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• 2023

Recently, as the fishery resources are depleted, expectations for productivity improvement by 'rearing fishery' in land farms are greatly rising. In the case of land farms, unlike ocean environments, it is easy to control and manage environmental and breeding factors, and has the advantage of being able to adjust production according to the production plan. On the other hand, unlike in the natural environment, there is a disadvantage in that operation costs may significantly increase due to the artificial management for fish growth. Therefore, profit maximization can be pursued by efficiently operating the farm in accordance with the planned target shipment. In order to operate such an efficient farm and nurture fish, an accurate growth prediction model according to the target fish species is absolutely required. Most of the growth prediction models are mainly numerical results based on statistical analysis using farm data. In this paper, we present a growth prediction model from a stochastic point of view to overcome the difficulties in securing data and the difficulty in providing quantitative expected values for inaccuracies that existing growth prediction models from a statistical point of view may have. For a stochastic approach, modeling is performed by introducing a Gaussian process regression method based on water temperature, which is the most important factor in positive growth. From the corresponding results, it is expected that it will be able to provide reference values for more efficient farm operation by simultaneously providing the average value of the predicted growth value at a specific point in time and the confidence interval for that value.

• Journal of The Korean Society of Clinical Toxicology
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• v.20 no.2
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• pp.58-65
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• 2022

Purpose: Alcohol is one of the most commonly co-ingested agents in deliberate self-poisoning (DSP) cases presenting at the emergency department (ED). The increased impulsivity, aggressiveness, and disinhibition caused by alcohol ingestion may have different clinical features and outcomes in cases of DSP. This study investigates whether alcohol co-ingestion affects the clinical features and outcomes of DSP patients in the ED. Methods: This was a single-center retrospective study. We investigated DSP cases who visited our ED from January 2010 to December 2016. Patients were classified into two groups: with (ALC+) or without (ALC-) alcohol co-ingestion. The clinical features of DSP were compared by considering the co-ingestion of alcohol, and the factors related to discharge against medical advice (AMA) of DSP were analyzed. Results: A total of 689 patients were included in the study, with 272 (39.5%) in the ALC+ group. Majority of the ALC+ group patients were middle-aged males (45-54 years old) and arrived at the ED at night. The rate of discharge AMA from ED was significantly higher in the ALC+ group (130; 47.8%) compared to the ALC- group (p=0.001). No significant differences were obtained in the poisoning severity scores between the two groups (p=0.223). Multivariate analysis revealed that alcohol co-ingestion (odds ratio [OR]=1.42; 95% confidence interval [CI], 1.01-1.98), alert mental status (OR=1.65; 95% CI, 1.17-2.32), past psychiatric history (OR=0.04; 95% CI, 0.01-0.28), age >65 years (OR=0.42; 95% CI, 0.23-0.78), and time from event to ED arrival >6 hrs (OR=0.57; 95% CI, 0.37-0.88) were independent predictive factors of discharge AMA (p=0.043, p=0.004, p=0.001, p=0.006, and p=0.010, respectively). Conclusion: Our results determined a high association between alcohol co-ingestion and the outcome of discharge AMA in DSP patients. Emergency physicians should, therefore, be aware that DSP patients who have co-ingested alcohol may be uncooperative and at high risk of discharge AMA.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.6
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• pp.375-380
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• 2022

High-speed railway bridges carry a risk of dynamic response amplification due to resonance caused by train loads, and running safety and riding comfort must therefore be reviewed through dynamic analysis in accordance with design codes. The running safety and ride comfort calculation procedure, however, is time consuming and expensive because dynamic analyses must be performed for every 10 km/h interval up to 110% of the design speed, including the critical speed for each train type. In this paper, a deep-learning-based prediction system that can predict the running safety and ride comfort in advance is proposed. The system does not use dynamic analysis but employs a deep learning algorithm. The proposed system is based on a neural network trained on the dynamic analysis results of each train and speed of the railway bridge and can predict the running safety and ride comfort according to input parameters such as train speed and bridge characteristics. To confirm the performance of the proposed system, running safety and riding comfort are predicted for a single span, straight simple beam bridge. Our results confirm that the deck vertical displacement and deck vertical acceleration for calculating running safety and riding comfort can be predicted with high accuracy.

• Archives of Plastic Surgery
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• v.49 no.6
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• pp.716-723
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• 2022

Background In March 2021, the United States Food and Drug Administration (FDA) safety communication cautioned against the use of acellular dermal matrix (ADM) products in breast reconstruction and reiterated that the FDA does not approve ADM use in breast surgery. This study aims to assess the safety of ADM use in breast reconstruction. Methods Women who underwent ADM and non-ADM assisted tissue expander (TE)-based breast reconstruction were identified using the National Surgical Quality Improvement Program database (2012-2019). Trends of ADM use over time, and 30-day outcomes of surgical site infection (SSI), dehiscence, and unplanned reoperation were assessed. Results Of the 49,049 TE-based breast reconstructive cases, 42.4% were ADM assisted and 57.6% non-ADM assisted. From 2012 to 2019, the use of ADM increased from 26.1 to 55.6% (relative risk [RR] =1.10; p < 0.01). Higher rates of SSI (3.9 vs. 3.4%; p = 0.003) and reoperation (7.4 vs. 6.0%; p < 0.001) were seen in the ADM cohort. There was no significant difference seen in dehiscence rates (0.7 vs. 0.7%; p = 0.73). The most common reoperation within 30 days for the ADM group (17.6%) was removal of TE without insertion of implant (current procedural terminology: 11,971). ADM-assisted breast reconstruction was associated with increased relative risk of SSI by 10% (RR = 1.10, confidence interval [CI]: 1.01-1.21; p = 0.03) and reoperation by 15% (RR = 1.15, CI: 1.08-1.23; p < 0.001). Conclusions ADM-assisted breast reconstruction more than doubled from 2012 to 2019. There are statistically higher complication rates of SSI (0.5%) and reoperation (1.4%) with ADM use in TE-based breast reconstruction, suggesting that reconstruction without ADM is safe when comparing immediate postoperative outcomes.