This study aims to model an accident that occurred at building demolition work sites in Gwangju in 2021 by using functional resonance analysis method(FRAM) and to understand a range of factors contributing to the accident based on the concepts and principles of FRAM and Safety-II. The nature of building demolition works needs to be understood from the viewpoint of socio-technical systems. Not only technical factors but also non-technical factors, including human, organizational, and political factors, and their complicated interrelationships should be considered in the modeling and analysis of accidents happening in the works. Because of the inherent complexity of a demolition works, it is unlikely to specify all of the necessary activities to be conducted in the works and their accountable actors. Additionally, unexpected situations are likely to happen and therefore some activity procedures cannot be followed in a prescribed way, which means that workers sometimes should conduct their activities in an improvisional way. Those characteristics of building demolition works indicate that a traditional accident analysis method based on a linear cause-effect relationship would be inadequate, and that more systemic approaches that can deal with the socio-technical complexities and characteristics of demolition works should be used. With this in mind, we applied FRAM to the accident happening in Gwangju in 2021 and attempted to understand the accident based on the concepts and principles of FRAM and Safety-II (e.g. a functional variablity and its propagation to another function). Lastly, we also suggested ways to enhance the safety of building demolition working sites.

There has been a significant decline in the number of rail accidents in Korea since system safety management activities were introduced. Nonetheless, analyzing and preventing human error-related accidents is still an important issue in railway industry. As a railway system is increasingly automated and intelligent, the mechanism and process of an accident occurrence are more and more complicated. It is now essential to consider a variety of factors and their intricate interactions in the analysis of rail accidents. However, it has proved that traditional accident models and methods based on a linear cause-effect relationship are inadequate to analyze and to assess accidents in complex systems such as railway systems. In order to supplement the limitations of traditional safety methods, recently some systemic safety models and methods have been developed. Of those, FRAM(Functional Resonance Analysis Method) has been recognized as one of the most useful methods for analyzing accidents in complex systems. It reflects the concepts of performance adjustment and performance variability in a system, which are fundamental to understanding the processes of an accident in complex systems. This study aims to apply FRAM to the analysis of a rail accident involving human errors, which occurred recently in South Korea. Through the application of FRAM, we found that it can be a useful alternative to traditional methods in the analysis and assessment of accidents in complex systems. In addition, it was also found that FRAM can help analysts understand the interactions between functional elements of a system in a systematic manner.

RF magnetron sputtering 법으로 T a2 O5 세라믹 타겟과 S r2N b2 O7 세라믹 타겟을 동시 sputtering하여 저유전율 S r2(T a1-x , N bx)2 O7(STNO) 박막을 p-type Si (100) 기판 위에 증착하여 NDRO 강유전체 메모리 (Non-destructive read out ferro-electric random access memory)에 사용되는 Pt/STNO/Si (MFS) 구조의 응용 가능성을 확인하였다. Sr2Nb2 O7 (SN O) 타겟과 T a2 O5 타겟의 출력의 비를 100w/100w, 70w/100w, 그리고 50w/100w로 조절하면서 x 값을 달리하여 조성을 변화시켰다. 성장된 박막을 850˚C, 900˚C, 그리고 950˚C에서 1시간 동안 산소 분위기에서 열처리하였다. 조성과 열처리 온도에 따른 구조적 특징을 XRD에 의해 관찰하였으며 표면특성은 FE-SBM에 의해 관찰하였고, C-V 측정과 I-V 측정으로 박막의 전기적 특성을 조사하였다. SNO 타겟과 T a2 O5 타켓의 출력비에 따른 STNO 박막의 성장 결과 70W/170W의 출력비에서 성장된 STNO박막에서 Ta의 양이 상대적 맡은 x=0.4였으며 가장 우수한 C-V 특성 및 누설 전류 특성을 보였다. 이 조성에서 성장된 STNO박막은 3-9V외 인가전압에서 메모리 윈도우 갑이 0.5-8.3V였고 누설전류밀도는 -6V의 인가전압에서 7.9×10-8A /cm2였다.