Until all vehicles are equipped with autonomous driving technology, there will inevitably be mixed traffic conditions that consist of autonomous vehicles (AVs) and manual vehicles (MVs). Interactions between AVs and MVs have a negative impact on traffic flow. Cloverleaf interchanges (ICs) have a high potential to cause traffic accidents owing to merging and diverging. Analyzing the driving safety of cloverleaf ICs in mixed traffic flows is an essential element of proactive traffic management to prevent accidents. This study proposes a comprehensive simulation approach that integrates driving simulation (DS) and traffic simulation (TS) to effectively analyze vehicle interactions between AVs and MVs. The purpose of this study is to identify hazardous road spots for a freeway cloverleaf IC by integrating DS and TS in mixed traffic flow. The driving behavior data of MVs collected through a DS were used to implement vehicle maneuvering based on an intelligent driver model in the TS. The driving behavior of the AVs was implemented using the VISSIM parameters of the AVs presented in the CoEXist project. Additionally, the market penetration rate of AVs, ranging from 10% to 90% in 10% increments, was considered in the analysis. Deceleration rate to avoid crashes was adopted as the evaluation indicator, and pinpointing hazardous spot technique was used to derive hazardous road spots for the cloverleaf IC. The most hazardous road spot was identified in the deceleration lane where greater speed changes were observed. Hazardous road spots moved downstream within the deceleration lane as traffic volumes increased based on level of service. The number of AVs decelerating stably increased as traffic increased, thereby improving the safety of the deceleration lane. These results can be used to determine the critical point of warning information provision for preventing accidents when introducing AVs.
Sequential zone picking is an order picking method designed to enhance warehouse efficiency by dividing the storage area into multiple zones and picking items in a sequential order across these zones. Picked items are often placed in dedicated totes and transported between zones using a conveyor system, which manages the picking flow but can occasionally result in inefficiencies during the process. This study presents a variant of the sequential zone picking system, called a dual-lane zone picking system (DZP), which consists of two parallel conveyor lanes without buffers between consecutive zones. This conveyor configuration allows the picker in each zone to alternate processing between the two lanes, thereby lessening the constraints of tote transitions between zones and improving both system throughput and picker utilization. We design and conduct a series of experiments using a discrete-event simulation model to evaluate the performance of DZPs. The experiment results indicate that DZP surpasses the original single-lane zone picking system by shortening the system’s mean flow time in low flow intensity scenarios and achieving a higher maximum throughput and worker utilization in high flow intensity scenarios. Additionally, we investigate the effects of the number of zones and order batching size on the performance of DZP to gain further insights into the system’s operational control.
Purpose: This study aimed to analyze the reviewers’ evaluations of papers submitted to the Journal of the Korean Society for Simulation in Nursing between 2019 and June 2024. Methods: We analyzed 117 quantitative (69 published and 48 unpublished) and 16 qualitative (11 published and five unpublished) studies. The reviewers’ checklist-based evaluations were analyzed using means and standard deviations. The scope method was used to examine the reviewers’ subjective evaluations. Results: For quantitative studies, the highest average score among published papers was in the “Research Theme” category (3.64±0.73). Contrastingly, the lowest average scores were in the “Discussion” category, with 3.32±0.74 for quantitative studies and 3.23±0.74 for qualitative studies. In rejected papers, the “Discussion” category recorded the lowest scores, at 2.35±0.74 for quantitative studies and 1.92±0.76 for qualitative studies. Conclusion: The results demonstrated the research characteristics of this journal and focus of the review by providing information on the reviewers’ evaluations. Structured scientific research based on these results will contribute to improving the academic quality of journals by reinforcing the openness and systematicity of academic communication.
Purpose: This study aimed to identify the need for simulation education to strengthen patient safety competencies in nursing practice field experience and explore and analyze improvements in simulation education. Methods: Data were collected through focus group interviews with 31 participants from four groups of fourth-year nursing students and one group of new nurses from August 7, 2023 to February 11, 2024. Interview data were systematically reviewed by qualitative content analysis. Results: Five major themes were identified; (1) awareness of patient safety competencies among nursing students and new nurses, (2) awareness of patient safety education among nursing students and new nurses, (3) simulation education topics for strengthening patient safety competencies, (4) interfering factors of simulation education for strengthening patient safety competencies, and (5) facilitating factors of simulation education to strengthen patient safety competencies. Accordingly, 15 categories were derived, and the current status of simulation education for patient safety, educational needs, and improvements were reported. Conclusion: This study attempted to reflect on the needs of learners before developing a simulation education program and derive educational content to strengthen patient safety competencies.
This study was conducted to simulate the lifetime of the membrane by analyzing the performance of the membrane degraded by chlorine. Chlorine exposure under several conditions caused the degradation of the membrane, resulting in the absence of any salts and an extreme increase in permeability. When the n value was calculated and compared through CnT analysis and CTn analysis, the p values were all less than 0.005, but CTn analysis, which had a higher R2 value, was adopted to simulate the membrane lifetime. Power coefficients take on values higher than 1, indicating that the exposure time to chlorine has a greater influence on membrane deterioration than the chlorine exposure concentration at 20℃ and 30℃. In particular, the process should be operated at less than 0.5 ppm at 30°C, and the chlorine exposure time of 1 cycle should be set to within 15 hours. In addition, the sensitivity to chlorine increased by 10.5 to 12.2 times when the chlorine exposure temperature increased by 10°C through the correlation between the chlorine exposure cycle and membrane lifetime. The membrane lifetime investigated in this study is only an estimated value, entirely because of chlorine membrane deterioration, excluding raw water characteristics and the type of detergent. Accordingly, it is considered that the membrane lifetime simulation can be applied by comparing the membrane performance with the actual process based on the filtration performance of membrane deterioration by chlorine.
Determining the number of operators who set up the machines in a human-machine system is crucial for maximizing the benefits of automated production machines. A man-machine chart is an effective tool for identifying bottlenecks, improving process efficiency, and determining the optimal number of machines per operator. However, traditional man-machine charts are lacking in accounting for idle times, such as interruptions caused by other material handling equipment. We present an adjusted man-machine chart that determines the number of machines per operator, incorporating idleness as a penalty term. The adjusted man-machine chart efficiently deploys and schedules operators for the hole machining process to enhance productivity, where operators have various idle times, such as break times and waiting times by forklifts or trailers. Further, we conduct a simulation validation of traditional and proposed charts under various operational environments of operators’ fixed and flexible break times. The simulation results indicate that the adjusted man-machine chart is better suited for real-world work environments and significantly improves productivity.
The waste secondary battery contains a significant amount of valuable metals, making its recycling highly desirable. However, conventional chemical methods for recycling are environmentally unfriendly and cost-ineffective. Rather than the chemical method, this paper deals with a mechanical method for recovering electrode materials from waste secondary batteries by blowing pressurized air onto the interface area between the electrode and the separator. Especially, in this study, the effective blowing angle were searched by simulating the separation of the electrode material from the separator through 1-way fluid structure interaction analysis based on the Cohesive Zone Modeling technique.
This study aimed to explore nursing students' experience of learning cardiopulmonary resuscitation (CPR) in a web-based virtual simulation (vSim) through analysis of the reflection journals. Method: From June to July 2020, data were collected from 48 fourth-year nursing students who performed the simulation by reviewing prompt feedback on their CPR performance. The contents of the reflection journals were analyzed using NVivo qualitative data analysis software. Results: Nursing students experienced unfamiliarity with the English-based virtual environment as well as psychological pressure and anxiety about emergencies. Incorrect interventions were identified in the following order of frequency: violation of defibrillator guidelines, missing fundamental nursing care, error in applying an electrocardiogram monitor, inadequate initial response to cardiac arrest, insufficient chest compression, and inadequate ventilation. Lastly, the participants learned the importance of embodied knowledge, for knowing and acting accurately and reacting immediately, and their attitudes as nurses, such as responsibility, calmness, and attentiveness. Learning strategies included memory retention through repetition, real-time feedback analysis, pre-learning, and imagining action sequences in advance. The level of achievement, time required, CPR quality, and confidence improved with behavior-modification strategies developed through self-reflection. Conclusion: Educational interventions that are based on understanding accurate algorithms can strengthen selfawareness of mistakes to improve efficient imparting of CPR education.
Dry storage of nuclear fuel is compromised by threats to the cladding integrity, such as creep and hydride reorientation. To predict these phenomena, spent fuel simulation codes have been developed. In spent fuel simulation, temperature information is the most influential factor for creep and hydride formation. Traditional fuel simulation codes required a user-defined temperature history input which is given by separate thermal analysis. Moreover, geometric changes in nuclear fuel, such as creep, can alter the cask’s internal subchannels, thereby changing the thermal analysis. This necessitates the development of a coupled thermal and nuclear fuel analysis code. In this study, we integrated the 2D FDM nuclear fuel code GIFT developed at SNU with COBRA -SFS. Using this, we analyzed spent nuclear stored in TN-24P dry storage cask over several decades and identified conditions posing threats due to phenomena like creep and hydrogen reorientation, represented by the burnup and peak cladding temperature at the start of dry storage. We also investigated the safety zone of spent nuclear fuel based on burnup and wet storage duration using decay heat.
본 연구의 목적은 시뮬레이션 실습 교육에서 임상수행능력에 대한 명확한 개념의 속성을 규명 하고 이를 조직화하여 임상수행능력에 대한 이론적 근거를 마련하기 위해 시도되었다. 연구 방법으로는 Walker And Avant의 개념분석 방법을 사용하였다. KISS, KMbase, DBpia, RISS, PubMed, CINAHL, Medline의 데이터베이스에서 보건의료인 교육을 위한 시뮬레이션 교육이 권고된 시점인 2000년부터 2023 년 4월까지 보고된 논문을 수집하였다. 연구 결과 임상수행능력의 속성은 (1) 지식, 판단, 기술의 종합적인 능력, (2) 의료 환경 변화에 능숙히 대처하는 능력, (3) 간호 대상자의 요구에 적절하게 대응하여 간호 역할 을 수행하는 능력이다. 본 연구는 시뮬레이션 실습 교육에서 임상수행능력에 대한 연구가 활발한 상황에서 간호학적 관점의 중요성을 인식하고, 개념분석을 한 연구로서 의의가 있다. 본 연구에서 나타난 시뮬레이 션 실습 교육에서 임상수행능력 속성을 포함한 훈련 프로그램 및 도구를 개발하고 이를 활용하여 프로그램 의 효과를 측정하는 것이 필요할 것으로 사료된다.
본 논문에서는 3차원 엮임 재료의 재료 물성치들을 효율적으로 분석하고 추후 최적설계 연구에 활용하기 위해서 파라메트릭 배치 해석 워크플로우를 제시하였다. 3차원 엮임 재료를 구성하는 와이어들 사이의 간격을 설계 매개변수로 하는 파라메트릭 모델에 대해 서 임의의 변수 조합을 가지는 2,500개의 수치 모델을 생성하였으며, 상용 프로그램인 매트랩과 앤시스의 여러 모듈을 사용하여 체적 탄성계수, 열전도도, 유체투과율과 같은 다양한 재료 물성치들을 배치 해석을 통해서 자동으로 얻어질 수 있도록 구성하였다. 이와 같 이 얻어진 대용량의 재료 물성치 데이터베이스를 활용해서 회귀 분석을 수행하였으며, 그 결과 설계 변수들과 재료 물성치 사이의 경 향성과 수치 해석 결과의 정확도를 검증하였다. 또한 확보된 데이터베이스를 통해서 3차원 엮임 재료의 물성치를 예측할 수 있는 인 공 신경망을 구성하고 학습시켰으며, 그 결과 임의의 설계 매개변수 값들을 가지는 엮임 재료 모델에 대해서 구조 및 유체해석 과정 없 이도 높은 정확도로 재료 물성치들을 추정할 수 있음을 확인하였다.
PURPOSES : Because a driving simulator typically focuses on analyzing a driver’s driving behavior, it is difficult to analyze the effect on the overall traffic flow. In contrast, traffic simulation can analyze traffic flow, that is, the interaction between vehicles; however, it has limitations in describing a driver’s driving behavior. Therefore, a method for integrating the simulator and traffic simulation was proposed. Information that could be controlled through driving experiments was used, and only the lane-change distance was considered so that a more natural driving behavior could be described in the traffic flow. METHODS : The simulated connection method proposed in this study was implemented under the assumption of specific traffic conditions. The driver’s lane-changing behavior (lane-changing distance, deceleration, and steering wheel) due to the occurrence of road debris was collected through a driving study. The lane-change distance was input as a parameter for the traffic simulation. Driving behavior and safety were compared between the basic traffic simulation setting, in which the driver's driving behavior information was not reflected, and the situation in which the driving simulator and traffic simulation were integrated. RESULTS : The number of conflicts between the traffic simulation default settings (Case 1) and the situation in which the driving simulator and traffic simulation were integrated (Case 2) was determined and compared for each analysis. The analysis revealed that the number of conflicts varied based on the level of service and road alignment of the analysis section. In addition, a statistical analysis was performed to verify the differences between the scenarios. There was a significant difference in the number of conflicts based on the level of service and road alignment. When analyzing a traffic simulation, it is necessary to replicate the driving behavior of the actual driver. CONCLUSIONS : We proposed an integration plan between the driving simulator and traffic simulation. This information can be used as fundamental data for the advancement of simulation integration methods.
Essential macleod program (EMP) was used to optimize the transmittance of the transparent conducting layers in an oxidemetal- oxide structure. For EMP simulation, the optical coefficient of the material was extracted using an ellipsometer. Following the simulation studies, oxide-metal-oxide samples were fabricated experimentally, and their optical and electrical properties were analyzed. Multilayer SiInZnO/Ag/Siinzno (S/A/S) structures were grown on glass substrates using radio frequency (RF) and direct current (DC) sputtering at room temperature. Due to the occurrence of destructive interference at the metal and oxide interface, the S/A/S structure exhibited excellent optical properties. As the thickness of the top and bottom oxide layers was increased, the transmittance spectrum was red-shifted due to partial wave interference at the Ag interface. Change in thickness of the top oxide layer had a greater effect on the transmittance than that of the bottom oxide layer. This was due to the difference in refractive index occurring at each interface. Change in Ag thickness shifted the absorption edge in the short wavelength region. Whereas electrical properties, such as sheet resistance and carrier concentration, were found to be dependent on thickness of the sandwiched metal layer. An excellent figure of merit of 63.20 ×10−3Ω−1 was obtained when the thickness of the Ag layer was 11 nm, and the top and bottom oxide layer thickness were 45 and 60 nm, respectively. These values suggest promising optoelectronic properties and are encouraging for future transparent electrode applications.
A methodology is under development to reconstruct and predict the long-term evolution of the natural barrier comprising the site of radioactive waste disposal. The natural barrier must protect the human zone from radionuclides for a long time. So for this, we need to be able to restore the evolution of the bedrock constituting the natural barrier from the past to the present and to predict from the present to the future. A methodology is being studied using surface outcrop, tunnel face of KURT (KAERI Underground Research Tunnel), and drill core at KAERI (Korea Atomic Energy Research Institute). Among them, drill core is an essential material for identifying deep geological properties, which could not be confirmed near the surface when considering the geological condition of the repository in the deep part. In this study, we selected several qualitative and quantitative analyses to construct a deep lithological model from the disposal perspective. These were applied to drill core samples around the KURT. There are the dikes presumed the Cretaceous were intruded by Jurassic granitoids in the study area. Analyzing trace elements of each rock type in the study area classified through geochemical characteristics and microstructure in previous studies made it possible to obtain qualitative information on the petrogenetic process. In addition, synthesizing the quantitative numerical age allows for grasping the evolution of bedrock, including intrusion and cutting relationships. LAICPMS was used for determining the age of zircons in plutonic rocks. The highly reliable 40Ar-39Ar method was selected for volcanic rocks because it can correct the loss of Ar gas and obtain the values of two types of Ar isotopes in a single sample. As a result, it was possible to infer the formation environment of rocks through anomalies in specific trace element content. And according to the numerical ages, it was possible to support the known separated rock type found in previous studies or to present a quantitative precedence relation for unclassified rocks. These methods could be applied to reconstruct the long-term evolution of bedrock within natural barriers.
In this study, computer simulation of the drawbridge structure was performed to verify the validity of the design and to evaluate its safety. For this, the follower bracket was modeled, and the parts of the follower bracket were connected using 1D elements. The boundary condition applied moments to the rotation shaft of the girder gear in the clockwise and counterclockwise directions, and the connection between the upper parts was modeled using 1D elements to model the bolted connection. In case of rotational shaft deformation, an analysis was performed on the displacement occurring in the structure during the opening/closing operation. As a result of structural analysis of the follower bracket for various cases, the stress at the connection was lower than the tensile strength and yield strength, so it was evaluated as safe. Through this, we intend to use it as a data that can identify anomalies.
게임의 세계는 최근 몇 년간 빠르게 진화해 왔다. 특히 여성 게이머들의 수가 증가하면서, 이들의 구체적인 요구를 이해할 필요성이 대두되고 있다. 본 연구는 여성 데이트 시뮬레이션 모바일 게임 및 게임 캐릭터 디자 인 분야에서 여성 게임 이용자의 요구와 선호를 분석하고자 한다. 최근에는 여성 중심의 게임에 대한 관심이 증가하고 있지만, 여성 게임 플레이어를 대상으로 한 게임은 아직 충분히 개발되지 않았다. 따라서 본 연구에 서는 광범위한 문헌 검토와 설문조사를 통해 여성 게이머들의 선호를 파악하고, 이를 바탕으로 여성 데이트 시뮬레이션 모바일 게임의 캐릭터 디자인 방향을 제안한다. 이를 통해 게임 디자이너 및 개발자들은 현대 여 성들의 요구를 더욱 잘 이해하고, 높은 수준의 게임을 개발할 수 있을 것이다. 더 줄일 수 있다. 그리고 제안 된 모델은 앞으로 다른 게임이나 스포츠 게임에도 적용될 것이다.
Forest fires in Korea usually start in the fall and occur every year until spring. Most wildfires are human resources that combine topographical characteristics and carelessness, and failure to respond in the initial stage and lack of cleanup are spreading to large-scale wildfires. In order to prevent these wildfires, active cooperation from the public is essential. As can be seen from recent wildfires, the attention of the public is needed above all else because large-scale wildfires in Korea are occurring due to the people's negligence. If a wildfire spreads and becomes large, it causes damage to life and property, and the damage is irreversible. In this study, various methods were used to prevent forest fires and improve initial suppression ability. In order to minimize damage, the model analyzed by the 119 Special Rescue Team in Gangwon, Chungcheong and nearby forest fires was analyzed on the combustion progress and wind direction by time period. The propagation speed by the wind direction was simulated. Until now, most of the wildfires have been extinguished by firefighting, but I hope that the Forest Service will take the lead and maintain coordination with related organizations.