• Nuclear Engineering and Technology
• /
• v.55 no.10
• /
• pp.3913-3923
• /
• 2023

Todays, medium energy resolution detectors are preferably used in radioisotope identification devices(RID) in nuclear and radioactive material categorization. However, there is still a need to develop or enhance « automated identifiers » for the useful RID algorithms. To decide whether any material is SNM or NORM, a key parameter is the better energy resolution of the detector. Although masking, shielding and gain shift/stabilization and other affecting parameters on site are also important for successful operations, the suitability of the RID algorithm is also a critical point to enhance the identification reliability while extracting the features from the spectral analysis. In this study, a RID algorithm based on Bayesian statistical method has been modified for medium energy resolution detectors and applied to the uranium gamma-ray spectra taken by a LaBr3:Ce detector. The present Bayesian RID algorithm covers up to 2000 keV energy range. It uses the peak centroids, the peak areas from the measured gamma-ray spectra. The extraction features are derived from the peak-based Bayesian classifiers to estimate a posterior probability for each isotope in the ANSI library. The program operations were tested under a MATLAB platform. The present peak based Bayesian RID algorithm was validated by using single isotopes(²⁴¹Am, ⁵⁷Co, ¹³⁷Cs, ⁵⁴Mn, ⁶⁰Co), and then applied to five standard nuclear materials(0.32-4.51% at.²³⁵U), as well as natural U- and Th-ores. The ID performance of the RID algorithm was quantified in terms of F-score for each isotope. The posterior probability is calculated to be 54.5-74.4% for ²³⁸U and 4.7-10.5% for ²³⁵U in EC-NRM171 uranium materials. For the case of the more complex gamma-ray spectra from CRMs, the total scoring (ST) method was preferred for its ID performance evaluation. It was shown that the present peak based Bayesian RID algorithm can be applied to identify ²³⁵U and ²³⁸U isotopes in LEU or natural U-Th samples if a medium energy resolution detector is was in the measurements.

• Nuclear Engineering and Technology
• /
• v.55 no.10
• /
• pp.3543-3548
• /
• 2023

Shutdown chemistry evolution is performed in nuclear power plants at each refueling outage (RFO) to establish safe conditions to open system and minimize inventory of corrosion products in the reactor coolant system (RCS). After hydrogen peroxide is added to RCS during shutdown chemistry evolution, corrosion products are released and are removed by filters and ion exchange resins in the chemical volume control system (CVCS). Shutdown chemistry evolution including RCS clean-up time to remove released corrosion products impacts the critical path schedule during RFOs. The estimation of clean-up time prior to RFO can provide more reliable actions for RCS clean-up operations and transients to operators during shutdown chemistry. Electric Power Research Institute (EPRI) shutdown calculator (SDC) enables to provide clean-up time by Co-58 peak activity through operational data from nuclear power plants (NPPs). In this study, we have investigated the results of EPRI SDC by shutdown chemistry data of Co-58 activity using NPP data from previous cycles and modeled the estimated clean-up time by EPRI SDC using average Co-58 activity of the NPP. We selected two RFO data from the NPP to evaluate EPRI SDC results using the purification time to reach to 1.3 mCi/cc of Co-58 after hydrogen peroxide addition. Comparing two RFO data, the similar purification time between actual and computed data by EPRI SDC, 0.92 and 1.74 h respectively, was observed with the deviation of 3.7-7.2%. As the modeling the estimated clean-up time, we calculated average Co-58 peak concentration for normal cycles after cycle 10 and applied two-sigma (2σ, 95.4%) for predicted Co-58 peak concentration as upper and lower values compared to the average data. For the verification of modeling, shutdown chemistry data for RFO 17 was used. Predicted RCS clean-up time with lower and upper values was between 21.05 and 27.58 h, and clean-up time for RFO 17 was 24.75 h, within the predicted time band. Therefore, our calculated modeling band was validated. This approach can be identified that the advantage of the modeling for clean-up time with SDC is that the primary prediction of shutdown chemistry plans can be performed more reliably during shutdown chemistry. This research can contribute to improving the efficiency and safety of shutdown chemistry evolution in nuclear power plants.

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

• Tunnel and Underground Space
• /
• v.34 no.3
• /
• pp.218-230
• /
• 2024

Recently, many studies have been conducted for safety management in construction sites by incorporating computer vision. Anchor box parameters are used in state-of-the-art deep learning-based object detection and segmentation, and the optimized parameters are critical in the training process to ensure consistent accuracy. Those parameters are generally tuned by fixing the shape and size by the user's heuristic method, and a single parameter controls the training rate in the model. However, the anchor box parameters are sensitive depending on the type of object and the size of the object, and as the number of training data increases. There is a limit to reflecting all the characteristics of the training data with a single parameter. Therefore, this paper suggests a method of applying multiple parameters optimized through data split to solve the above-mentioned problem. Criteria for efficiently segmenting integrated training data according to object size, number of objects, and shape of objects were established, and the effectiveness of the proposed data split method was verified through a comparative study of conventional scheme and proposed methods.

• Food Science and Preservation
• /
• v.30 no.2
• /
• pp.262-271
• /
• 2023

The objective of this study is to compare and assess the effectiveness of real-time polymerase chain reaction (RT-PCR), loop-mediated isothermal amplification (LAMP), and the selective agar plate method for the detection of Salmonella spp. and Listeria monocytogenes in ready-to-eat (RTE) foods. In RTE foods, the detection performance of the three methods (RT-PCR [SureTect^TM kit and PowerChek^TM kit], LAMP [3M MDS], selective agar) were similar at 0-10, 10-50, 50-100, and 100- CFU/mL of Salmonella spp. and L. monocytogenes. We found that with RT-PCR, the Ct value of salad was significantly higher (p<0.05) than other RTE foods, indicating that fiber plays a critical role as an obstacle to the rapid detection of Salmonella spp. However, the Ct value displayed a mixed pattern according to the inoculation level of L. monocytogenes. The use of rapid detection kits and machines mostly depends on the user's choice, with accuracy, ease of use, and economy being the primary considerations. As an RT-PCR kit, SureTect^TM and PowerChek^TM showed high accuracy in detecting Salmonella spp. and L. monocytogenes in RTE foods, showing that they can replace the existing RT-PCR kits available. Additionally, LAMP also showed excellent detection performance, suggesting that it has the potential to be used as a food safety management tool.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.24 no.1
• /
• pp.125-132
• /
• 2024

The purpose of this study is to discover a drone utilization model tailored to local characteristics, propose directions for building a drone demonstration city based on demand surveys for drone activation, and suggest ways to utilize and support a drone application system. First, according to the survey results, there was a high understanding of and necessity for drone demonstration projects, particularly in addressing urban issues, which were deemed to have a significant impact. Second, based on the analysis of priorities and short- and long-term approaches, disaster-related tasks were evaluated as a priority, requiring an approach through medium- to long-term strategies. Third, it was noted that budgetary considerations emerged as the most critical issue during project implementation. Practitioners and experts expressed willingness to actively introduce drone-based technologies into their work when budget and technology were ready. Budgetary constraints were identified as the most significant obstacle to proper implementation, emphasizing the need for resolution. Fourth, the necessity of demand surveys during project development was identified in certain areas. Demand surveys were deemed essential for drone-based demonstration city construction, and a survey indicated that public leadership in this regard was also necessary. Fifth, concerning approaches in specific areas, the field of safety and disaster management was highlighted as the most crucial for application.

• Journal of the Korean Society of Radiology
• /
• v.84 no.3
• /
• pp.606-614
• /
• 2023

Purpose This study aimed to evaluate the efficacy and safety of transcatheter arterial embolization (TAE) for bleeding due to uterine body cancer. Materials and Methods In this retrospective study, six patients with varying types of uterine body cancer who underwent TAE for bleeding control were investigated. Angiographic findings, cross-sectional images, TAE details, and clinical outcomes were studied. Technical and clinical success rates were calculated. Results The identified patients had endometrioid adenocarcinoma, sarcoma, and gestational trophoblastic neoplasia, and most were patients with advanced-stage cancer. In four patients, tumor bleeding presented as vaginal bleeding. Technical success was achieved in all seven TAE procedures in six patients. Two patients with recurrent masses who had undergone hysterectomy presented with hematochezia, and TAE was able to provide technical success in these patients as well. The clinical success rate was 50%, indicating bleeding control for > 1 week. Rebleeding was directly associated with death in one patient. On the following day, mild fever was observed in one patient. Conclusion TAE can be considered an effective and safe method of bleeding control for uterine body cancer, especially during critical periods throughout the disease course of patients with inoperable, advanced-stage cancer.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.10
• /
• pp.1497-1507
• /
• 2016

The purpose of this study was to conduct importance and performance analysis of sanitation management in workers at small and medium foodservice industries using HACCP prerequisites. Questionnaires were distributed to 500 small and medium foodservice industry workers in Seoul Gyeonggi province, and a total of 458 responses were used for analysis. Factors with relatively low comparison degree were as follows. 'Handwashing and clean uniform of employee in the workplace', 'regular checking and managing of trapped vermin and rodents', 'checking stocked raw materials', 'recording and filing the results of improved food safety factors', and 'regular cleaning and sterilizing of monitoring tools' factors must be improved along with their performance levels through sanitation education. According to the IPA results, among the 15 HACCP prerequisite factors with high importance but low performance were '2. Regular checking and managing of trapped vermin and rodents', '4. Handwashing and clean uniform of employee in the workplace', '14. Preventing food cross-contamination'. Furthermore, the small and medium foodservice industry IPA with high importance but low performance were 'Regular checking and managing of trapped vermin and rodents', 'Handwashing and clean uniform of employee in the workplace', and 'Preventing food cross-contamination' for the small foodservice industry, along with 'Vermin and rodents control' and 'Recording and filing the results of improved food safety factors' for the medium foodservice industry. Thus, there is a need for reinforced hygiene education through case studies on actual food service establishments to fulfill sanitation guidelines and set amended guides for much-needed items for small and mid-sized food service.

• Journal of Korean Society of Transportation
• /
• v.32 no.3
• /
• pp.266-279
• /
• 2014

For the evaluation of roadway safety, diverse methods, including before-after studies, simple comparison using historic traffic accident data, methods based on experts' opinion or literature, have been applied. Especially, many research efforts have developed traffic accident prediction models in order to identify critical elements causing accidents and evaluate the level of safety. A traffic accident prediction model must secure predictability and transferability. By acquiring the predictability, the model can increase the accuracy in predicting the frequency of accidents qualitatively and quantitatively. By guaranteeing the transferability, the model can be used for other locations with acceptable accuracy. To this end, traffic accident prediction models using non-linear regression, artificial neural network, and structural equation were developed in this study. The predictability and transferability of three models were compared using a model development data set collected from 90 signalized intersections and a model validation data set from other 33 signalized intersections based on mean absolute deviation and mean squared prediction error. As a result of the comparison using the model development data set, the artificial neural network showed the highest predictability. However, the non-linear regression model was found out to be most appropriate in the comparison using the model validation data set. Conclusively, the artificial neural network has a strong ability in representing the relationship between the frequency of traffic accidents and traffic and road design elements. However, the predictability of the artificial neural network significantly decreased when the artificial neural network was applied to a new data which was not used in the model developing.

• Journal of Gastric Cancer
• /
• v.6 no.2
• /
• pp.103-108
• /
• 2006

Purpose: The circular stapled Billroth I gastrectomy has been gradually popularized because of several advantages. Thus, this study aims to identify what to be supplemented for the safety of this technique by examining the potential complication after the circular stapled Billroth I gastrectomy. Materials and Methods: This study selected 594 patients who underwent the circular stapled Billroth I gastrectomy because of the gastric cancer in our department of surgery from Jan. 1998 to Dec. 2004 as the subjects. As of Jan. 2001 when the bleeding on the anastomosis site was visually checked through the small incision at the opposite curvature to the lesion of the stomach to be resected and so the operation was completed, the patients were divided into the Group I (n=219) and Group II (n=375), which were the patients before and after Jan. 2001, respectively. Then, the clinical characteristics and postoperative anastomotic complications of both groups were compared. Results: For the comparison of complications between two groups, the anastomotic leakage was found in four cases in Group I and three cases in Group II (p=0.196). The stenosis on the anastomosis region was not observed in both groups. The bleeding on the anastomosis region illustrates the statistically significant difference between Group I and Group II, with 43 cases and 2 cases, respectively (P=0.0019). Conclusion: The circular stapled Billroth I gastrectomy is recommended because of several advantages of this technique. However, the bleeding on the anastomosis site may be indicated as the critical issue. Accordingly, the visual check on the bleeding on the anastomosis site during the operation will improve the safety of circular stapler.