• 대한안전경영과학회지
• /
• 제14권2호
• /
• pp.23-33
• /
• 2012

Recent technological advances in the domestic railway industry have turned out to deliver a profound impact on the forefront of other industries as well. Furthermore, the introduction of the high-speed railway systems has made it possible to travel around our country in a day, thereby changing our life styles a lot. However, it has been well recognized that many factors can cause unanticipated accidents during the operation. One of the causes is known to be the human errors made by the train operators in locomotive cabs. The problem is getting more serious as the trains run at high speed. As such, the objective of this paper is on how to improve the work environment of the locomotive cabs. Our approach is based on the systems engineering methodology. Specifically, we first identify the context and scope of the problem to be solved. We then continue our effort in deriving the requirements set to accomplish the improvement. These results are utilized in constructing a computer-aided management system for test and evaluation intended for the improvement. The approach taken and the results obtained in this paper is expected to make a contribution on the route to keeping our nation's technologies on the competitive edges in the high-speed railway systems industry.

• 한국추진공학회지
• /
• 제25권3호
• /
• pp.127-137
• /
• 2021

발사대시스템은 다양한 설비로 구성된다. 이들 설비를 원격 운용하는 발사관제시스템은 제어 알고리즘 개발과 검증에 많은 시간과 노력이 소요된다. 알고리즘 검증은 소프트웨어 제작자가 시험절차서에 기반한 시뮬레이션 상태 값을 입력하고, 알고리즘 흐름에 따라 출력 결과를 확인하는 과정을 통해 이루어진다. 이러한 검증 과정은 반복적으로 수행되므로 작업 오류를 쉽게 유발할 수 있다. 본 논문에서는 작업 오류의 최소화와 검증 기간 단축이 가능한 스크립트 시험절차서 기반의 효율적인 자동화 검증 방법을 제안하며, 발사대의 고압가스 공급설비와 전자식 유공압패널설비 제어 알고리즘 검증시험에 적용한 결과를 제시한다.

• 한국항행학회논문지
• /
• 제28권1호
• /
• pp.87-94
• /
• 2024

항공산업의 발전에도 불구하고 조종사의 인적오류에 의한 항공기 사고는 지속해서 발생하고 있다. 인적오류에 의한 항공기 사고의 원인은 비행안전을 저해하는 위해(hazard) 요인을 사전에 제거하지 못해 사고로 이어지는 것이다. 본 연구는 국내 항공사에 근무하는 운항승무원과 일반항공 (general aviation)의 조종사를 대상으로, 비행안전을 위협하는 여러 가지 위해 요인 중에서 조종사에게 심리적, 신체적으로 영향을 미치는 직무스트레스와 피로, 불안감이 안전행동에는 어떠한 영향을 미치는지 살펴보았다. 아울러 직무스트레스와 안전행동의 간에 안전문화의 매개효과를 확인하기 위한 실증분석을 실시하였다. 연구 결과에 의하면 직무스트레스는 조종사의 안전행동에 직접적인 영향을 줄 뿐만이 아니라 안전분위기, 보고문화와 같은 항공사의 안전문화에도 영향을 미친다는 것이다. 이러한 조종사의 직무스트레스와 안전문화, 안전행동간의 상관관계를 통해 안전관리시스템의 성과를 제고하고자 한다.

• 수산해양기술연구
• /
• 제60권2호
• /
• pp.152-160
• /
• 2024

We analyzed risk factors of coastal gillnet fishers during fishing process and considered work safety measures to reduce safety accidents during fishing using a UWB (ultra wideband) based positioning system. The static position accuracy of the UWB based positioning system was 45 cm. When entering a port, there is a risk of falling overboard. When casting a net, there was a risk of falling overboard due to being hit by fishing gear or guards, or getting caught in a buoy line or sinker line. When hauling a net, there is a risk of getting caught between fishing gear and net hauler, and the risk of musculoskeletal disorders due to repetitive work over a long period of time. Most safety accidents during work on fishing boats are blamed on human errors of the fisher and skipper, but safety accidents occur due to a mixture of mechanical and equipment factors, work and environmental factors, and management factors in addition to human errors. Therefore, the 4E were presented as countermeasures against the 4M, which are causes of safety accidents, and the proposed measures were used to identify risk factors for operation process, comply with work safety rules, and ensure the wearing of personal protective equipments. We need to reduce safety accidents during work by making it part of our daily routine. These research results can be used in the future for optimal placement of fishing gear and fishing nets in other coastal industries where safety accidents occur frequently.

• Advanced Composite Materials
• /
• 제18권4호
• /
• pp.297-314
• /
• 2009

A design method is proposed to optimize the stacking sequence of laminated composite plates for desired vibration characteristics. The objective functions are the natural frequencies of the laminated plates, and three types of optimization problems are studied where the fundamental frequency and the difference of two adjacent frequencies are maximized, and the difference between the target and actual frequencies is minimized. The design variables are a set of discrete values of fiber orientation angles with prescribed increment in the layers of the plates. The four lamination parameters are used to describe the bending property of a symmetrically laminated plate, and are optimized by a gradient method in the first stage. A new technique is introduced in the second stage to convert from the optimum four lamination parameters into the stacking sequence that is composed of the optimum fiber orientation angles of all the layers. Plates are divided into sub-domains composed of the small number of layers and designed sequentially from outer domains. For each domain, the optimum angles are determined by minimizing the errors between the optimum lamination parameters obtained in the first step and the parameters for all possible discrete stacking sequence designs. It is shown in numerical examples that this design method can provide with accurate optimum solutions for the stacking sequence of vibrating composite plates with various boundary conditions.

• 한국항해학회지
• /
• 제12권2호
• /
• pp.1-22
• /
• 1988

The transportations of most of cargoes in world trade have been fulfilled through sea lanes and it seems this trend will not change in near future. Nowadays, inview of the technical aspects of merchant vessels, they are continuously enlarged in hull size and greatly specialized in structure for the cargo spaces and dramatically automatized in navigating, piloting, cargo operating and various other operations, which unavoidably require high technicals in operating the modern merchant vessels. On the contrary to the trend of requiring of operating high technicals, the capabilities of crew on board have been gradually declining in technical competence and their morale for accomplishing their duties on board vessels has greatly falled won compared with that of old days. The above result inevitably brings many problems in operating modern vessels and causes accidents which are avoidable through good competence and high morale of the crew. We intend to analyze the causes of several great sea accident with which it seems some human errors are connected more or less directly or indirectly. We hope that this study could suggest some measures which help to prevent the recurrence of similar accidents by Korean ship's crews.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• 제4권2호
• /
• pp.165-171
• /
• 2004

Robots will be able to coexist with humans and support humans effectively in near future. One of the most important aspects in the development of human-friendly robots is to cooperation between humans and robots. In this paper, we proposed a method for multi-object identification in order to achieve such human-centered system and robot localization in intelligent space. The intelligent space is the space where many intelligent devices, such as computers and sensors, are distributed. The Intelligent Space achieves the human centered services by accelerating the physical and psychological interaction between humans and intelligent devices. As an intelligent device of the Intelligent Space, a color CCD camera module, which includes processing and networking part, has been chosen. The Intelligent Space requires functions of identifying and tracking the multiple objects to realize appropriate services to users under the multi-camera environments. In order to achieve seamless tracking and location estimation many camera modules are distributed. They causes some errors about object identification among different camera modules. This paper describes appearance based object representation for the distributed vision system in Intelligent Space to achieve consistent labeling of all objects. Then, we discuss how to learn the object color appearance model and how to achieve the multi-object tracking under occlusions.

• 한국항공운항학회지
• /
• 제22권4호
• /
• pp.1-7
• /
• 2014

The purpose of study is to investigate the current user interface level of air traffic control system with the usability analysis and satisfaction survey questionnaire on user satisfaction. Think aloud protocol is used to identify not only task analysis, but also the level of user-friendliness of the FIMS and ASDE system, and the user interface questionnaires was conducted by QUIS. We collected data from 6 controllers for Think aloud protocol and 15 controllers for QUIS in Incheon airport. The results showed that the system was the valuable tool for ensuring human performance with the support of memory and the facilitation of decision-making tasks. It helps air traffic controllers perform better and minimize errors in a congested time. The human-computer interface system design, however, was not applied, which led to the increase of workload. Air traffic controller participation in software development provided excellent examples for applications in terms of software in FIMS. Based on these results, the study provided that the usability of system interface was necessary to take into account human factors. The development and design of system was discussed in User Interface environment.

• Computers and Concrete
• /
• 제20권6호
• /
• pp.719-729
• /
• 2017

A considerable research is available on the seismic response of Reinforced Concrete (RC) shear wall-frame buildings, but the studies on the reliability of such buildings, with the consideration of human error, are limited. In the present study, a detailed procedure for reliability assessment of RC shear wall-frame building subjected to earthquake loading against serviceability limit state is presented. Monte Carlo simulation was used for the reliability assessment. The procedure was implemented on a 10-story RC building to demonstrate that the shear walls improve the reliability substantially. The annual and life-time failure probabilities of the studied building were estimated by employing the information of the annual probability of earthquake occurrence and the design life of the building. A simple risk-based cost assessment procedure that relates both the structural life-time failure probability and the target reliability with the total cost of the building was then presented. The structural failure probability (i.e., the probability of exceeding the allowable drift) considering human errors was also studied. It was observed that human error in the estimation of total load and/or concrete strength changes the reliability sharply.

• 자동차안전학회지
• /
• 제13권4호
• /
• pp.129-143
• /
• 2021

This paper proposes actuator fault detection and adaptive fault-tolerant control algorithms using performance index and human-like learning for longitudinal autonomous vehicles. Conventional longitudinal controller for autonomous driving consists of supervisory, upper level and lower level controllers. In this paper, feedback control law and PID control algorithm have been used for upper level and lower level controllers, respectively. For actuator fault-tolerant control, adaptive rule has been designed using the gradient descent method with estimated coefficients. In order to adjust the control parameter used for determination of adaptation gain, human-like learning algorithm has been designed based on perceptron learning method using control errors and control parameter. It is designed that the learning algorithm determines current control parameter by saving it in memory and updating based on the cost function-based gradient descent method. Based on the updated control parameter, the longitudinal acceleration has been computed adaptively using feedback law for actuator fault-tolerant control. The finite window-based performance index has been designed for detection and evaluation of actuator performance degradation using control error.