• Journal of Auto-vehicle Safety Association
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• v.14 no.2
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• pp.57-69
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• 2022

Recently, as interest in self-driving cars has increased worldwide, research and development on the Advanced Driver Assist System is actively underway. Among them, the purpose of Adaptive Cruise Control (ACC) is to minimize the driver's driving fatigue through the control of the vehicle's longitudinal speed and relative distance. In this study, for the research of the ACC test in the real environment, the real-road test was conducted based on domestic-road test scenario proposed in preceding study, considering ISO 15622 test method. In this case, the distance measurement method using the dual camera was verified by comparing and analyzing the result of using the dual camera and the result of using the measurement equipment. As a result of the comparison, two results could be derived. First, the relative distance after stabilizing the ACC was compared. As a result of the comparison, it was found that the minimum error rate was 0.251% in the first test of scenario 8 and the maximum error rate was 4.202% in the third test of scenario 9. Second, the result of the same time was compared. As a result of the comparison, it was found that the minimum error rate was 0.000% in the second test of scenario 10 and the maximum error rate was 9.945% in the second test of scenario 1. However, the average error rate for all scenarios was within 3%. It was determined that the representative cause of the maximum error occurred in the dual camera installed in the test vehicle. There were problems such as shaking caused by road surface vibration and air resistance during driving, changes in ambient brightness, and the process of focusing the video. Accordingly, it was determined that the result of calculating the distance to the preceding vehicle in the image where the problem occurred was incorrect. In the development stage of ADAS such as ACC, it is judged that only dual cameras can reduce the cost burden according to the above derivation of test results.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.5
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• pp.233-252
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• 2022

Recently, various studies have been conducted to improve automated vehicle (AV) safety for AVs commercialization. In particular, the scenario method is directly related to essential safety assessments. However, the existing scenario do not have objectivity and explanability due to lack of data and experts' interventions. Therefore, this paper presents the AVs safety assessment extended scenario using real traffic accident data and vision transformer (ViT), which is explainable artificial intelligence (XAI). The optimal ViT showed 94% accuracy, and the scenario was presented with Attention Map. This work provides a new framework for an AVs safety assessment method to alleviate the lack of existing scenarios.

• Journal of the Korea Safety Management & Science
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• v.16 no.4
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• pp.81-90
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• 2014

Modern systems can be characterized by ever-increasing complexity of both the functionality and system scale. Thus, due to the complexity the chances of accidents resulting from systems failure can then be growing. Even worse is that those accidents could result in disastrous damage to the human being and properties as well. Therefore, the need for the developed systems to be assured with systems safety is apparent in a variety of industries such as rail, automobiles, airplanes, ships, oil refinery, chemical production plants, and so on. To this end, in the industry an appropriate safety standard has been published for its own safety-assured products. One of the core activities included in the most safety standards is hazard analysis. A conventional approach to hazard analysis seems to depend upon the scenarios derived from the ones used previously in similar systems or based on former experience. The objective of this paper is to study an improved process for scenario-based hazard analysis. To achieve the goal, the top-level safety requirements have first been reflected in the scenarios. By analyzing and using them, the result has then lead to the development of safety-assured systems. The method of modeling and simulation has been adopted in the generation and verification of scenarios to check whether the safety requirements are reflected properly in the scenarios. Application of the study result in the case of rail safety assurance has also been discussed.

• The Journal of Society for e-Business Studies
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• v.14 no.3
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• pp.71-85
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• 2009

Nowadays the research and development of various middleware for the ubiquitous computing environment has been demanded and many application services have been provided. The practical ubiquitous computing environment is the world where a variety of services based on RFID/USN devices are integrated with each other and make synergy effects all together. In the end user perspectives, there should be a middleware platform and business logic framework collaborating various services all together to satisfy the user requirements. In addition, the platform should provide the user to describe a scenario based on various event to maximize the collaboration. In this paper, we have proposed business logic framework which is supporting collaboration between heterogeneous service systems based on the user's scenario. We have also tried to show the efficiency and scalability of the proposed framework by providing the result of a couple of tests.

• Journal of Digital Convergence
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• v.19 no.1
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• pp.229-237
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• 2021

The purpose of this study is to verify the effects of Simulation-based Chest Tube Drainage Management Nursing Education on the Nursing Students' Response to Scenario Experiences, Confidence in Learning, and Problem Solving Abilities. This study was performed with a one-group pretest-posttest design, and a total of 133 junior nursing students have participated in the research (31 teams of simulation-based education). According to the results of the study, most of the students have shown a positive response to the scenario experience after the simulation training, while their confidence in learning and problem-solving skills have improved significantly. This proves that simulation-based training using simulators can be very effective in practical nursing training. It is expected that this research could make a meaningful contribution to improving the overall quality of field-oriented practical training and clinical practice.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.3
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• pp.169-177
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• 2021

In this paper, we propose a novel global navigation satellite system (GNSS) spoofing detection technique through an array antenna-based direction of arrival (DoA) estimation of satellite and spoofer. Specifically, we consider a sophisticated GNSS spoofing attack scenario where the spoofer can accurately mimic the multiple pseudo-random number (PRN) signals since the spoofer has its own GNSS receiver and knows the location of the target receiver in advance. The target GNSS receiver precisely estimates the DoA of all PRN signals using compressed sensing-based orthogonal matching pursuit (OMP) even with a small number of samples, and it performs spoofing detection from the DoA estimation results of all PRN signals. In addition, considering the initial situation of a sophisticated spoofing attack scenario, we designed the algorithm to have high spoofing detection performance regardless of the relative spoofing signal power. Therefore, we do not consider the assumption in which the power of the spoofing signal is about 3 dB greater than that of the authentic signal. Then, we introduce design parameters to get high true detection probability and low false alarm probability in tandem by considering the condition for the presence of signal sources and the proximity of the DoA between authentic signals. Through computer simulations, we compare the DoA estimation performance between the conventional signal direction estimation method and the OMP algorithm in few samples. Finally, we show in the sophisticated spoofing attack scenario that the proposed spoofing detection technique using OMP-based estimated DoA of all PRN signals outperforms the conventional spoofing detection scheme in terms of true detection and false alarm probability.

• Journal of The Korean Society of Agricultural Engineers
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• v.65 no.3
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• pp.69-82
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• 2023

Representative meteorological data of the rural water district, which is the spatial unit of the study, was produced using the grid-based national standard RCP scenario rainfall data provided by the Korea Meteorological Administration. The retrospective reproducibility of the climate model scenario data was analyzed, and the change in climate characteristics in the water district unit for the future period was presented. Finally the data characteristics and differences of each meteorological element according to various spatial resolution conversion and post-processing methods were examined. As a main result, overall, the distribution of average precipitation and R95p of the grid data, has reasonable reproducibility compared to the ASOS observation, but the maximum daily rainfall tends to be distributed low nationwide. The number of rainfall days tends to be higher than the station-based observation, and this is because the grid data is generally calculated using the area average concept of representative rainfall data for each grid. In addition, in the case of coastal regions, there is a problem that administrative districts of islands and rural water districts do not match. and In the case of water districts that include mountainous areas, such as Jeju, there was a large difference in the results depending on whether or not high rainfall in the mountainous areas was reflected. The results of this study are expected to be used as foundation for selecting data processing methods when constructing future meteorological data for rural water districts for future agricutural water management plans and climate change vulnerability assessments.

• Journal of Nutrition and Health
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• v.46 no.1
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• pp.50-60
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• 2013

The aims of this study were to estimate daily intake of macrominerals from beverages, liquid teas, and liquid coffees and to evaluate their potential health risks for Korean children and adolescents (1-to 19 years old). Assessment of dietary intake was conducted using the actual level of sodium, calcium, phosphorus, potassium, and magnesium in non-alcoholic beverages and (207 beverages, 19 liquid teas, and 24 liquid coffees) the food consumption amount drawn from "The Fourth Korea National Health and Nutrition Examination Survey (2007-2009)". To estimate the dietary intake of non-alcoholic beverages, 6,082 children and adolescents (Scenario I) were compared with 1,704 non-alcoholic beverage consumption subjects among them (Scenario II). Calculation of the estimated daily intake of macrominerals was based on point estimates and probabilistic estimates. The values of probabilistic macromineral intake, which is a Monte-Carlo approach considering probabilistic density functions of variables, were presented using the probabilistic model. The level of safety for macrominerals was evaluated by comparison with population nutrient intake goal (Goal, 2.0 g/day) for sodium, tolerable upper intake level (UL) for calcium (2,500 mg/day) and phosphorus (3,000-3,500 mg/day) set by the Korean Nutrition Society (Dietary Reference Intakes for Koreans, KDRI). For total children and adolescents (Scenario I), mean daily intake of sodium, calcium, phosphorus, potassium, and magnesium estimated by probabilistic estimates using Monte Carlo simulation was, respectively, 7.93, 10.92, 6.73, 23.41, and 1.11, and 95th percentile daily intake of those was, respectively, 28.02, 44.86, 27.43, 98.14, and 3.87 mg/day. For consumers-only (Scenario II), mean daily intake of sodium, calcium, phosphorus, potassium, and magnesium estimated by probabilistic estimates using Monte Carlo simulation was, respectively, 19.10, 25.77, 15.83, 56.56, and 2.86 mg/day, and 95th percentile daily intake of those was, respectively, 62.67, 101.95, 62.09, 227.92, and 8.67 mg/day. For Scenarios I II, sodium, calcium, and phosphorus did not have a mean an 95th percentile intake that met or exceeded the 5% of Goal and UL.

• Korean Management Science Review
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• v.28 no.3
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• pp.73-82
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• 2011

Basel II advanced measurement approaches for operational risk need to estimate the frequency and severity distribution of operational losses. Due to lack of internal loss data, the estimation is impossible in many cases and so external loss data might be used by scaling on asset or gross income. To get around lack of loss data, scenario analysis combined with loss distribution approach can be useful in calculating the capital charge of operational risk. However, scenario based loss distribution approach requires much time and effort. Instead we may apply the analytic hierarchy process to measure operational risk of financial institutions. The analytic hierarchy process combined with loss distribution approach is to estimate the capital charge of operational risk in other areas based on the operational VaR in an area with sufficient loss data. AHP provides a tool for timely measurement of operational risk in this rapidly changing global environment.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.22 no.2
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• pp.180-189
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• 2015

Purpose: The purpose of this study was to identify the types of errors that occurred and were recovered in a simulated transfusion scenario by nursing students. Methods: Twenty-eight teams of a total of 89 nursing students participated in a transfusion simulation using a high fidelity simulator. Data were collected by observing rule based errors and built in errors recovered according to the framework of Eindhoven model. Reflective journaling was used to identify perceived safety-threatening errors and commitment to improvement. Data were analyzed using descriptive statistics. Results: All teams committed the rule based errors in the scenario. The most common errors occurred in the coordination category related to communication with physician. Most of students perceived the transfusion reaction as a safety-threatening error. Conclusion: The findings indicate that students lack patient safety competence. The simulation training to decrease errors and improve safe practice provides nursing students with an effective strategy to develop patient safety competence.