• International Journal of Aeronautical and Space Sciences
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• v.15 no.2
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• pp.163-172
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• 2014

This paper proposes a novel guidance law based on the block backstepping sliding mode control and extended state observer (ESO), which also takes into account the autopilot dynamic characteristics of the near space interceptor (NSI), and the impact angle constraint of attacking the maneuvering target. Based on the backstepping control approach, the target maneuvers and the parameter uncertainties of the autopilot are regarded as disturbances of the outer loop and inner loop, respectively. Then, the ESO is constructed to estimate the target acceleration and the inner loop disturbance, and the block backstepping sliding model guidance law is employed, based on the estimated disturbance value. Furthermore, in order to avoid the "explosion of complexity" problem, first-order low-pass filters are also introduced, to obtain differentiations of the virtual control variables. The stability of the closed-loop guidance system is also proven, based on the Lyapunov theory. Finally, simulation results demonstrate that the proposed guidance law can not only overcome the influence of the autopilot dynamic delay and target maneuvers, but also obtain a small miss distance.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.2
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• pp.278-294
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• 2015

Considering the guidance and control problem of the near space interceptor (NSI) during the terminal course, this paper proposes a three-channel independent integrated guidance and control (IGC) scheme based on the backstepping sliding mode and finite time disturbance observer (FTDO). Initially, the three-channel independent IGC model is constructed based on the interceptor-target relative motion and nonlinear dynamic model of the interceptor, in which the channel coupling term and external disturbance are regarded as the total disturbances of the corresponding channel. Then, the FTDO is introduced to estimate the target acceleration and control system loop disturbances, and the feed-forward compensation term based on the estimated values is employed to effectively remove the effect of disturbances in finite time. Subsequently, the IGC algorithm based on the backstepping sliding mode is also given to obtain the virtual control moment. Furthermore, a robust least-squares weighted control allocation (RLSWCA) algorithm is employed to distribute the previous virtual control moment among the corresponding aerodynamic fins and reaction jets, which also takes into account the uncertainty in the control effectiveness matrix. Finally, simulation results show that the proposed IGC method can obtain the small miss distance and smooth interceptor trajectories.

• Proceedings of the Safety Management and Science Conference
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• 2005.11a
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• pp.74-82
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• 2005

안전사고 원인에 대하여 Near-Miss Report 분석을 근거로 하여, 재해원인에 대하여 접근해 보고, 이 Data를 참고로 첨단산업에서의 재해 유형을 분석해보고, 유형에 따른 기여인자를 기존 Human-ware, Hard-ware, System-ware를 구성요소로 해서 첨단산업에서의 각각의 수행인자의 비율 분석을 통한 판단한 결과는 Human-ware와 Hard-ware 비율은 4:1로 나타났고, 첨단사업장에서의 5년간의 사고건수를 근거로 원인에 대한 수행인자의 ANOVA로 분석하여 4개인자에 대한 분산 분석을 도출하였고 이에따른 Loss와 Time과 Accident 관계와 Effect of Intervention관계와 Reason's Accident Causation Model과 Perrow's Normal Accident Theory Model를 연관시켜서 첨단산업에서의 사고이론 Model를 추출해서 첨단산업에서의 안전사고에 대한 유형을 분석해서 사고를 사전에 제거키 위한 새로운 모델을 제시하고자 한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.4-6
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• 2016

준해양사고 통보제도(Marine Incidents Reporting System)는 우리나라의 선박소유자 및 선박운항자가 선박의 구조 설비 또는 운용과 관련하여 시정 또는 개선되지 않으면 선박과 사람의 안전 및 해양환경 등에 위해를 끼치거나 위해를 끼칠 수 있는 사태로서 해양사고를 제외한 사건이나 사고에 대하여 자율적으로 중앙해양안전심판원에 통보하도록 하여 심판원은 이를 분석하여 교훈을 발굴하고 정기적으로 업계에 전파하여 해양사고 예방에 도움이 되고자 하는 제도이다. 동 제도는 2010월 4월 조기 시행 한 후 시행 5년차에 접어들었지만 홍보부족, 선박의 특수성, 제도적 장치의 부족으로 통보제도 운영에 어려움을 격고 있다. 본 논문에서는 IMO 해양사고조사코드와 국내외 유사 준사고 보고제도 분석 후 통보대상자를 대상으로 준 해양사고 통보제도의 현황에 대한 설문을 실시하고 분석함으로써 동 제도의 활성화 방안을 제시하고자 한다.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.183-186
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• 2011

There are numerous crashed deaths or near-miss accidents in everywhere. The outbreak place is not just developing countries such as India and Iran, but also leading countries including Japan and German. The crashed death of pedestrian seems to be an unavoidable accident. However, it was revealed in social psychology field that the accident can be treated as a kind of physical phenomenon. In this study, we apply discrete element method frequently used in the field of two-phase flow to pedestrian flow with collective behavior psychology. This approach is a field of social science and physics, called computational sociology. The acquired results show that emergency exit size can be related with the wall slope of the exit.

• Journal of the Korea Safety Management & Science
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• v.11 no.3
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• pp.33-40
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• 2009

Steel and iron manufacture works exist that many latency risk as melting liquid of high temperature, work of high place, and so on. Once in a while, the accident case make use of basic data for latency risk analysis in a place of business. In this paper, we investigated the cause of the accident in steel an iron works. The result, we came across that many latency risk in steel and iron manufacture works. The main type of risk are fall, narrow, come flying, etc. Most of the latency risk type are repetition and conventional accident. Accordingly, steel and manufacture works must prevent to repetition and conventional accident.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.169-171
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• 2013

The ships always have had the risk of collision. There are also a number of near-miss situations especially in the congested area such as port entrance, restricted waters and crossing point of the ship's route. In those areas, the navigator might have more stress than other areas. If the collision risk of decided area is calculated, it might be possible to analyse the human factors by using this data. It is also helpful for deciding a position of aids to navigation or any other system for the safety navigation. For this purpose, the model of collision risk with AIS data has been explained in this paper. The calculated result from the proposed model has been examined by using the simulation.

• Journal of the Korean Society of Safety
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• v.37 no.2
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• pp.28-34
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• 2022

This study analyzes the impact that accidents and near misses have on clients' and contractors' awareness of safety culture. Due to the unique characteristic of employment structure in Korea, the occurrence of accidents differs by company size, which has relevant implications for the establishment of safety culture. Attention has been drawn to the importance of the management of accidents and near misses, with safety awareness acting as a core factor. A positive effect on the prevention of accidents could be achieved by noting the difference in safety awareness between clients and contractors and suggesting an associated suitable safety management system. In support of this study, a survey was distributed to workers in the automobile manufacturing industry (May-August 2020), and data from a total of 574 workers was collected and analyzed, including 399 clients' worksers and 175 contractors' workers. The questionnaire addressed participants' experiences of accidents and near misses as well as 50 items from the Nordic Occupational Safety Climate Questionnaire. Analysis of the responses was conducted using the methods of frequency analysis, Fisher's exact test, t-test, correlation analysis, and regression analysis. The results demonstrated that clients had more experiences with accidents and near misses compared to contractors. Additional differences between clients and contractors were noted in terms of the safety culture factors of learning, communication, and trust. A correlation was observed between the experience of accidents and safety justice management: for clients and contractors who experienced accidents, safety justice management was 9.4 times higher. Furthermore, clients' and contractors' awareness of employees' commitment to safety was determined to be 28.5 times higher in those who had experienced near misses This study concludes that, in order to improve accident prevention through the management of accidents and near misses, clients must focus on overseeing safety justice management and aspects of safety culture factors, while contractors must focus efforts on managing employees' commitment to safety. In further applications, this study could provide baseline data for health and safety activities in terms of the safety culture of clients and contractors. Further study on the establishment of safety culture as related to employment structure is proposed for future research.

• Progress in Medical Physics
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• v.25 no.4
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• pp.298-303
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• 2014

In this study, we examine the trends and types of incidents frequently occur during radiation therapy by using the data from the radiation oncology safety information system (ROSIS), according to discovery method explores the development direction of future research accident cause factor control method. This study was carried out analysis of incident data in ROSIS nearly 1163 cases in last 11 years from 2003 to 2013. We categorized into treatment methods, found the time, discoverer of occupations and finding ways to analyze the data. Then, we calculate the percentage and the classification for each item. About 1163 cases of incident cases including the near miss cases, external radiation therapy, brachytherapy and other were 97%, 2% and 1%. In the case was improperly planned dose delivery was 44% (497 cases) which 429 cases (86%) was found before 3 fractions and 13 cases were found after 11 fractions. The investigation was found to be distributed in various a found times. Approximately 42% of found time was during treatment and 29% of patients were found the problem during inspection chart. Occupation to discover the most radiation accidents was the radiation therapist (53%) who works in treatment room. Among 1163 incidence cases, 24% cases were found the accident before the treatment, therefore most of accident were found after of during the treatment (70%, 813 cases). This trend is acquired through ROSIS analysis, is expected to be not significantly different in the case of Korea, so it is necessary more diverse and systematic research for the prevention and early detection by using the ROSIS data.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.3
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• pp.287-293
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• 2017

The purpose of this study is to keep the safety of the car ferry passengers and vessels by investigating and analyzing vessel safety management systems in Korea and China. To this end, we investigated Korea-China car ferries and the current status and causes of global marine accidents corresponding to the sizes of the vessels from Korea and China. Furthermore, we investigated car ferries' crew management and safety management. As a result of the analysis of the ferry accident, the causes of human error and ship's age were the greatest, but the ship's companies showed a negative stance regarding the age restriction. It seems that it is necessary to utilize the near-miss accident reporting system and differentiate the management of ship's aging. Also, it was analyzed that both the ship company and the crew of the ship need to strengthen their awareness of safety management.