• Journal of Biomedical Engineering Research
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• v.45 no.1
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• pp.10-19
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• 2024

The purpose of this study is to conduct a summative evaluation of the usability of a general-purpose ventilator to determine whether it can be used for its intended purpose in the intended environment by the intended user and to find possible errors in use. The importance of ventilators has increased due to the accelerated aging of the population and the impact of the pandemic. In addition, patients who require ventilators are often in critical condition, so even a small error in use can be fatal. Therefore, it is important to ensure that the ventilator has sufficient stability and can be used satisfactorily without inconvenience to the user. In this study, we conducted a usability test with 17 respiratory nurses with more than 3 years of experience using the ventilator. We analyzed the task success rate, satisfaction, and opinions of the intended users while going through a total of 17 scenarios. Satisfaction was captured through an ASQ questionnaire and subjective opinions were captured through a detailed opinion questionnaire. The results showed a high level of satisfaction with an average score of 6.3 for the use scenarios. Evaluators expressed satisfaction with the overall visibility and versatility of the features, but noted that improvements were needed for calibration tasks with low task success rates. As the calibration method is different from other equipment, it was suggested that specific explanations of the calibration method and the picture that appears when calibrating are needed, and that if relevant training is provided, the equipment can be used without problems. If the usability evaluation is not limited to securing efficiency and satisfaction from the intended users, but also continuously receives feedback from users to prepare for use in emergency environments such as pandemic situations, it will be very helpful to seize opportunities such as emergency authorization in future situations, and ultimately contribute to patient safety by reducing use errors.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.6
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• pp.1-10
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• 2023

Strong Critics of' Moral Hazard, due to plummeting severely their stock price down and damage falling on plain investor, has been skyrocketed against massively and simultaneously exercising stock option right of C-Level members in Stock market listed startups right after IPO regardless of proper and legal process followed. Korean Financial Supervisory Board initiate new act of extending to apply'Lock-up Rule'even to stock option of core interest group after IPO. However, it will cause startups and venture more difficulties to recruit top level of talented staffs. This paper aims to propose RSU(Restricted Stock Unit) as alternative to breakthrough the current deadlock issue with respect to stock option controversy many startups facing. This paper to meet goal, first, including Korean introducing status of RSU, it clarify the concept of RSU by comparing exploration with Restricted Stock and define characteristic of RSU by comparing Stock Option. Second, it bring more effective ways of startups introducing RSU in Korea overcoming its limitations and challenges. Third, it carry out FGI to legal expert deeply involved of introducing RSU in Korea at policy domain. FGI focus on defining core challenging factors and their level of huddles of introducing RSU in Korea with proposing breakthrough policies to landing RSU softly in Korea. Fourth, it suggest valid policies of introducing and stabilizing RSU in Korea completely. This paper expect some contributions Korean startups and venture on finding market friendly right breakthrough out of stock option dilemma currently in.

• Industry Promotion Research
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• v.9 no.1
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• pp.39-45
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• 2024

Dangerous tasks that occur every day at industrial site manufacturing plants, which have recently been making rapid changes, were classified by type, and the effect of mobile circuit television (CCTV) on safety accidents among daily safety management methods was analyzed. The subject of the study is about 3,000 workers who manage the infrastructure facility sector to supply utilities such as gas, water, and electricity to the display manufacturing process located in Asan City, and the study was conducted based on the daily dangerous work from 2019 to 2022, and during this study period, many construction works such as new investment and expansion of construction and manufacturing processes were occurring at the site. As a result, the rate of safety accidents and exposure to risks are expanding, and most of the safety accidents occurred because the sectors that did not follow the basics and the safety measures on the site were not implemented. In this paper, it was confirmed that there is an accident reduction effect according to the relationship between the dangerous work classified according to the work importance and the mobile CCTV shooting rate. Considering the characteristics of the manufacturing plant site, it can be used to play the role of basic data for preventing safety accidents based on the expansion of the introduction of a new safety management culture in the future.

• Korean Journal of Radiology
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• v.23 no.2
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• pp.159-171
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• 2022

Objective: This study aimed to investigate the impact of baseline values and temporal changes in body composition parameters, including skeletal muscle index (SMI) and visceral adipose tissue area (VAT), measured using serial computed tomography (CT) imaging on the prognosis of operable breast cancers in Asian patients. Materials and Methods: This study retrospectively included 627 Asian female (mean age ± standard deviation [SD], 53.6 ± 8.3 years) who underwent surgery for stage I-III breast cancer between January 2011 and September 2012. Body composition parameters, including SMI and VAT, were semi-automatically calculated on baseline abdominal CT at the time of diagnosis and follow-up CT for post-treatment surveillance. Serial changes in SMI and VAT were calculated as the delta values. Multivariable Cox regression analysis was used to evaluate the association of baseline and delta SMI and VAT values with disease-free survival. Results: Among 627 patients, 56 patients (9.2%) had breast cancer recurrence after a median of 40.5 months. The mean value ± SD of the baseline SMI and baseline VAT were 43.7 ± 5.8 cm²/m² and 72.0 ± 46.0 cm², respectively. The mean value of the delta SMI was -0.9 cm²/m² and the delta VAT was 0.5 cm². The baseline SMI and VAT were not significantly associated with disease-free survival (adjusted hazard ratio [HR], 0.983; 95% confidence interval [CI], 0.937-1.031; p = 0.475 and adjusted HR, 1.001; 95% CI, 0.995-1.006; p = 0.751, respectively). The delta SMI and VAT were also not significantly associated with disease-free survival (adjusted HR, 0.894; 95% CI, 0.766-1.043; p = 0.155 and adjusted HR, 1.001; 95% CI, 0.989-1.014; p = 0.848, respectively). Conclusion: Our study revealed that baseline and early temporal changes in SMI and VAT were not independent prognostic factors regarding disease-free survival in Asian patients undergoing surgery for breast cancer.

• Clinical Endoscopy
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• v.56 no.6
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• pp.761-768
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• 2023

Background/Aims: Self-expandable metallic stents (SEMSs) are widely adopted for the palliation of dysphagia in patients with malignant esophageal strictures. An important adverse event is the development of SEMS-induced esophagorespiratory fistulas (SEMS-ERFs). This study aimed to assess the risk factors related to the development of SEMS-ERF after SEMS placement in patients with esophageal cancer. Methods: This retrospective study was performed at the Instituto do Cancer do Estado de São Paulo. All patients with malignant esophageal strictures who underwent esophageal SEMS placement between 2009 and 2019 were included in the study. Results: Of the 335 patients, 37 (11.0%) developed SEMS-ERF, with a median time of 129 days after SEMS placement. Stent flare of 28 mm (hazard ratio [HR], 2.05; 95% confidence interval [CI], 1.15-5.51; p=0.02) and post-stent chemotherapy (HR, 2.0; 95% CI, 1.01-4.00; p=0.05) were associated with an increased risk of developing SEMS-ERF, while lower-third tumors were a protective factor (HR, 0.5; 95% CI, 0.26-0.85; p=0.01). No difference was observed in overall survival. Conclusions: The incidence of SEMS-ERFs was 11%, with a median time of 129 days after SEMS placement. Post-stent chemotherapy and a 28 mm stent flare were associated with a higher risk of SEMS-ERF.

• Journal of Gastric Cancer
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• v.20 no.2
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• pp.152-164
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• 2020

Purpose: To compare long-term disease-free survival (DFS) between patients receiving tegafur/gimeracil/oteracil (S-1) or capecitabine plus oxaliplatin (CAPOX) adjuvant chemotherapy (AC) for gastric cancer (GC). Materials and Methods: This retrospective multicenter observational study enrolled 983 patients who underwent curative gastrectomy with consecutive AC with S-1 or CAPOX for stage II or III GC at 27 hospitals in Korea between February 2012 and December 2013. We conducted propensity score matching to reduce selection bias. Long-term oncologic outcomes, including DFS rate over 5 years (over-5yr DFS), were analyzed postoperatively. Results: The median and longest follow-up period were 59.0 and 87.6 months, respectively. DFS rate did not differ between patients who received S-1 and CAPOX for pathologic stage II (P=0.677) and stage III (P=0.899) GC. Moreover, hazard ratio (HR) for recurrence did not differ significantly between S-1 and CAPOX (reference) in stage II (HR, 1.846; 95% confidence interval [CI], 0.693-4.919; P=0.220) and stage III (HR, 0.942; 95% CI, 0.664-1.337; P=0.738) GC. After adjustment for significance in multivariate analysis, pT (4 vs. 1) (HR, 11.667; 95% CI, 1.595-85.351; P=0.016), pN stage (0 vs. 3) (HR, 2.788; 95% CI, 1.502-5.174; P=0.001), and completion of planned chemotherapy (HR, 2.213; 95% CI, 1.618-3.028; P<0.001) were determined as independent prognostic factors for DFS. Conclusions: S-1 and CAPOX AC regimens did not show significant difference in over-5yr DFS after curative gastrectomy in patients with stage II or III GC. The pT, pN stage, and completion of planned chemotherapy were prognostic factors for GC recurrence.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.3
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• pp.679-690
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• 2015

The need to remove the cause of traffic accidents by improving the engineering system for a vehicle and the road in order to minimize the accident hazard. This is likely to cause traffic accident continue to take a large and significant social cost and time to improve the reliability and efficiency of this generally poor road, thereby generating a lot of damage to the national traffic accident caused by improper environmental factors. In order to minimize damage from traffic accidents, the cause of accidents must be eliminated through technological improvements of vehicles and road systems. Generally, it is highly probable that traffic accident occurs more often on roads that lack safety measures, and can only be improved with tremendous time and costs. In particular, traffic accidents at intersections are on the rise due to inappropriate environmental factors, and are causing great losses for the nation as a whole. This study aims to present safety countermeasures against the cause of accidents by developing an intersection Traffic safety evaluation model. It will also diagnose vulnerable traffic points through BPA (Back -propagation algorithm) among artificial neural networks recently investigated in the area of artificial intelligence. Furthermore, it aims to pursue a more efficient traffic safety improvement project in terms of operating signalized intersections and establishing traffic safety policies. As a result of conducting this study, the mean square error approximate between the predicted values and actual measured values of traffic accidents derived from the BPA is estimated to be 3.89. It appeared that the BPA appeared to have excellent traffic safety evaluating abilities compared to the multiple regression model. In other words, The BPA can be effectively utilized in diagnosing and practical establishing transportation policy in the safety of actual signalized intersections.

• Radiation Oncology Journal
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• v.17 no.2
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• pp.129-135
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• 1999

Purpose : This study evaluated early bowel complications in cervix cancer patients, following external radiotherapy (ERT and high dose rate intracavitary radiation (HDR ICR). Factors affecting the risk of developing early bowel complications and its incidence are analyzed and discussed Materials and Methods : The study is the retrospective review of 66 patients who received radiotherapy at Chungbuk National University Hospital from April 1994 to December 1998. The patients underwent 41.4 or 50.4 Gy ERT according to FIGO stage and tumor size, then A point dose was boosted to 71.4 or 74.4 Gy using a remotely controlled afterloading Buchler HDR ICR. The EORTC/RTOG morbidity criteria were used to grade early bowel complications, which are valid from day 1, the commencement of therapy, through day 90. The actuarial incidence, severity of complications were investigated and clinical pretreatment factors relevant to complications were found through univariate (Wilcoxon) and multivariate (Cox proportional hazard model) analysis. Results : Of the 66 patients, 30 patients (46$\%$) developed early bowel complications; 25 patients (38$\%$) with grade 1 or 2, 4 patients (0$\%$) with grade 3 and 1 patient (2$\%$) with grade 4. The complications usually began to occur 3 weeks after the commencement of radiotherapy. The actuarial incidence of early bowel complications was 41$\%$ at 10 weeks. The early bowel complications were associated significantly with an old age and a history of previous abdomino-pelvic surgery. All three patients who had a protracted overall treatment time (about 2 weeks) due to severe bowel complication, suffered from pelvic recurrences. Conclusion : Forty six percent of patients experienced early bowel complications, most of which were grade 1 or 2 and relieved spontaneously or by medication. The patients with an old age or a previous surgery have a high probability of early complications and they may be less compliant with planned radiotherapy. So more careful precaution is necessary for these patients.

• Radiation Oncology Journal
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• v.19 no.3
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• pp.224-229
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• 2001

Purpose : The aim of this study is to analyze the treatment failure patterns and the risk factors for locoregional or distant failure of uterine cervical carcinoma treated with radiation therapy. Materials and methods . A retrospective analysis was undertaken of 154 patients treated with curative radiation therapy in Gyeongsang National University Hospital from April 1989 through December 1997. According to FIGO classification, 12 patients were stage IB, 24 were IIA, 98 were IIB, 1 were IIIA, 17 were IIIB, 2 were IVA. Results : Overall treatment failure rate was $42.1\%$ (65/154), and that of complete responder was $31.5\%$ (41/130). Among 65 failures, 25 failed locoregionally, another 25 failed distantly, and 15 failed locoregionally and distantly. Multivariate analysis confirmed tumor size (>4 cm) as risk factor for locoregional failure, and tumor size (>4 cm), pelvic lymph node involvement as risk factors for distant failure. Conclusion : On the basis of results of our study and recent published data of prospective randomized study for locally advanced uterine cervical carcinoma, we concluded that uterine cervical carcinoma with size more than 4 cm or pelvic lymph node involvement should be treated with concurrent chemoradiation.

• Journal of The Korean Ophthalmological Society
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• v.59 no.12
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• pp.1166-1172
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• 2018

Purpose: To investigate the efficacy, and identify predictors of success of selective laser trabeculoplasty (SLT) in open-angle glaucoma (OAG) patients after adjusting for intraocular pressure (IOP) changes in the untreated fellow eye. Methods: This retrospective chart review included 52 eyes of 52 OAG patients who underwent SLT in one eye and were followed-up for at least 1 year after the procedure. The IOP was measured before the treatment, at 1, 2, and 3 months posttreatment, and every 3 months thereafter. To account for the possible influence of IOP fluctuations on laser outcomes, post-laser IOP values of the treated eye of each patient were also analyzed, after adjusting for IOP changes in the untreated fellow eye. Success was defined as an IOP decrease ${\geq}20%$ of the pretreatment IOP. The success rate was determined based on Kaplan-Meier survival analysis and factors predictive of success were analyzed using the Cox proportional hazard model. Results: The mean pretreatment IOP was $23.17{\pm}6.96mmHg$. The mean IOP reduction was $5.59{\pm}4.78mmHg$ (29.7%) and the success rate was 65.4% at 1 year. The adjusted mean IOP reduction was $4.70{\pm}4.67mmHg$ (23.9%) and the adjusted success rate was 53.9%. Pretreatment IOP was associated with SLT success; the higher the pretreatment IOP, the greater the post-laser IOP reduction (p = 0.025). Age and mean deviation index did not show a significant association with SLT success (p = 0.066 and p = 0.464, respectively). Conclusions: SLT is a safe and effective alternative method of IOP reduction in OAG patients. Herein, pretreatment IOP was the only factor significantly associated with SLT success. IOP fluctuations of the untreated eye should be considered for a better understanding of the impact of treatment.