• 한국안전학회지
• /
• 제14권2호
• /
• pp.178-191
• /
• 1999

More than twenty methods were suggested for Human Reliability Analysis (HRA) in the field of safety analysis for Nuclear Power Plants (NPPs). However, there is still a high uncertainty on the analysis and a difficulty in performing HRA. New methods and approaches are under studying to overcome such limitations of current HRA. This paper presents some results of study to analysis limitations of current HRA in viewpoint of user, i.e., HRA analyst. The limitation analysis was based on 89 human error events modeled in a Probabilistic Safety Assessment (PSA) project for NPPs in Korea. Total 17 specific limitations were identified and categorized into seven groups. Important analysis has also been undertaken to assess the order of priority among those limitations. Finally, seven requirements with priority ranking were generated for an advanced framework and methodology of HRA.

• 한국보건간호학회지
• /
• 제13권1호
• /
• pp.25-40
• /
• 1999

This study was to identify various personal characteristics between those having a helper and those not having a helper for ADL and IADL performance in noninstitutionalized elders. Secondary analysis was done with the data collected in 1994 national survey of aged householders. Of the elders with ADL limitations $47.8\%$ had no helper. while $26.2\%$ of those with IADL limitations had no helper. Those elders with a helper experienced more limitations in ADL and in IADL than those with no helper. Most of the helpers were family members. whereas very few had a formal helper. Age period and subjective economic status were significantly different between the groups with a helper and with no helper for both ADL and IADL. Compared to the elders with a helper. those elders with no helper had fewer children living together. whereas they had more grandchildren. They also had more contacts with friends or neighbors. Health status. in general. was worse in those elders with a helper than those with no helper. Logistic regression analysis revealed that ADL and IADL limitations had largest influence on having an ADL helper. The odds ratios for low levels of subjective economic status were very high. As for having an IADL helper. IADL score was the most important predictor. In particular. ADL limitations had a negative effect on having an IADL helper. This finding may indicate the urgency of ADL needs. which leads to the lack of an IADL helper when both ADL and IADL limitations are present. Considering the nature of ADL. those disabled elders with low economic status need public support for their daily activities and for home visiting nursing services. There should be studies of examining the adequacy of help in satisfying basic needs for performing ADL and IADL in elders.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2009년도 추계학술대회 논문집
• /
• pp.797-803
• /
• 2009

The accurate prediction of dynamic characteristics of high speed rotors, such as gas turbines, is important to avoid the possibility of operating the machinery near the critical speeds or unstable speed regions. However, the dynamic analysis methods and softwares for gas turbines have been developed in the process of producing many gas turbines by manufacturers and most of them have seldom been disclosed to the public. Recently, commercial FEM softwares, such as SAMCEF, ANSYS and NASTRAN, started supporting some rotordynamics analysis modules based on 3-D finite elements. In this paper, the dynamic analysis method using commercial S/W, especially ANSYS, is attempted for the small-size gas turbine engine rotor, and the analysis capability and limitations of its rotordyamics module are evaluated for further improvement of the module. As the preliminary procedure, the rotordyamic analysis capability of ANSYS was tested and evaluated with the reference models of the well-known dynamics. The limitations in application of the rotordynamics module were then identified. Under the current capability and limitations of ANSYS, it is shown that Lee diagram, a new frequency-speed diagram enhanced with the concept of $H{\infty}$ in rotating machinery, can be indirectly obtained from FRFs computed from harmonic response analysis of ANSYS. Finally, it is demonstrated based on the modeling and analysis method developed in the process of the S/W verification that the conventional Campbell diagram, Lee diagram, mode shapes and critical speeds of the small-size gas turbine engine rotor can be computed using the ANSYS rotordynamics module.

• 한국소음진동공학회논문집
• /
• 제20권1호
• /
• pp.36-44
• /
• 2010

The accurate prediction of dynamic characteristics of high speed rotors, such as gas turbines, is important to avoid the possibility of operating the machinery near the critical speeds or unstable speed regions. However, the dynamic analysis methods and softwares for gas turbines have been developed in the process of producing many gas turbines by manufacturers and most of them have seldom been disclosed to the public. Recently, commercial FEM softwares, such as SAMCEF, ANSYS and NASTRAN, started supporting some rotordynamics analysis modules based on 3-D finite elements. In this paper, the dynamic analysis method using commercial S/W, especially ANSYS, is attempted for the small-size gas turbine engine rotor, and the analysis capability and limitations of its rotordyamics module are evaluated for further improvement of the module. As the preliminary procedure, the rotordyamic analysis capability of ANSYS was tested and evaluated with the reference models of the well-known dynamics. The limitations in application of the rotordynamics module were then identified. Under the current capability and limitations of ANSYS, it is shown that Lee diagram, a new frequency-speed diagram enhanced with the concept of $H{\infty}$ in rotating machinery, can be indirectly obtained from FRFs computed from harmonic response analysis of ANSYS. Finally, it is demonstrated based on the modeling and analysis method developed in the process of the S/W verification that the conventional Campbell diagram, Lee diagram, mode shapes and critical speeds of the small-size gas turbine engine rotor can be computed using the ANSYS rotordynamics module.

• International Journal of Internet, Broadcasting and Communication
• /
• 제14권4호
• /
• pp.11-19
• /
• 2022

Data mining has broad applications that reach beyond scholarly and scientific research and provide internet search engine services that are commonly used forms of Text and Data Mining('TDM') of websites. The exceptions and limitations for data mining provide a competitive advantage in the global race for policy innovation because it permits researchers to conduct computational analysis - TDM on any materials to which they have access. For this purpose, Japan and the EU added limitations on copyright to legalize some TDM research through amendments to copyright law, and the U.S. copyright law has allowed data mining by the fair use provision. On the other hand, there are no explicit exceptions and limitations for data mining under the Korean Copyright Act, and there are no cases considering data mining fair use. We review comparatively exceptions and limitations on copyright which will help to encourage AI-related business by using more data smoothly through the mining process and extracting more valuable information.

• 한국IT서비스학회지
• /
• 제20권3호
• /
• pp.75-86
• /
• 2021

As artificial intelligence is actively studied, chatbot systems are being applied to various fields. In particular, many chatbot systems for psychological counseling have been studied that can comfort modern people. However, while most psychological counseling chatbots are studied as rule-base and deep learning-based chatbots, there are large limitations for each chatbot. To overcome the limitations of psychological counseling using such chatbots, we proposes a novel psychological counseling AI chatbot system. The proposed system consists of a GPT-2 model that generates output sentence for Korean input sentences and an Electra model that serves as sentiment analysis and anxiety cause classification, which can be provided with psychological tests and collective intelligence functions. At the same time as deep learning-based chatbots and conversations take place, sentiment analysis of input sentences simultaneously recognizes user's emotions and presents psychological tests and collective intelligence solutions to solve the limitations of psychological counseling that can only be done with chatbots. Since the role of sentiment analysis and anxiety cause classification, which are the links of each function, is important for the progression of the proposed system, we experiment the performance of those parts. We verify the novelty and accuracy of the proposed system. It also shows that the AI chatbot system can perform counseling excellently.

• 한국안전학회지
• /
• 제28권1호
• /
• pp.158-163
• /
• 2013

While job stress evaluations are reported in the recent surveys upon the nuclear power plants(NPPs), any significant advance in the types of questionnaires is not currently found. There are limitations to their usefulness as analytic tools for the management of safety resources in NPPs. Data mining(DM) has emerged as one of the key features for data computing and analysis to conduct a survey analysis. There are still limitations to its capability such as dimensionality associated with many survey questions and quality of information. Even though some survey methods may have significant advantages, often these methods do not provide enough evidence of causal relationships and the statistical inferences among a large number of input factors and responses. In order to address these limitations on the data computing and analysis capabilities, we propose an advanced procedure of survey analysis incorporating the DM method into a statistical analysis. The DM method can reduce dimensionality of risk factors, but DM method may not discuss the robustness of solutions, either by considering data preprocesses for outliers and missing values, or by considering uncontrollable noise factors. We propose three steps to address these limitations. The first step shows data mining with response surface method(RSM), to deal with specific situations by creating a new method called response surface data mining(RSDM). The second step follows the RSDM with detailed statistical relationships between the risk factors and the response of interest, and shows the demonstration the proposed RSDM can effectively find significant physical, psycho-social, and environmental risk factors by reducing the dimensionality with the process providing detailed statistical inferences. The final step suggest a robust stress management system which effectively manage job stress of the workers in NPPs as a part of a safety resource management using the surrogate variable concept.

• 한국IT서비스학회지
• /
• 제7권3호
• /
• pp.159-174
• /
• 2008

The purpose of this study was to introduce a case that used web2.0 techniques to overcome the limitations of current DACUM method. For the purpose, firstly, we summarized the characteristics and limitations of current DACUM as a method to develop an occupational curriculum. The summary indicated that the results of DACUM process are likely to be influenced by the selection procedure of out-performers. In addition, current DACUM method is difficult to be adapted to big organizations, difficult to reflect rapidly changing society, and lack of qualitative review for the findings. To overcome these limitations, Seoul city designed a transformed DACUM method based on web2.0 techniques. The most outstanding features of the transformed DACUM method were web-based peer review systems to validate the findings of DACUM workshop. We concluded that the transformed DACUM method was proper to big size organizations faced with rapid changes and some organizations with special needs to establish their training systems based on the results of job analysis. Finally, we discussed several practical tips for the Seoul city's method.

• 에너지공학
• /
• 제13권4호
• /
• pp.267-274
• /
• 2004

스크린 메쉬윅 및 소결윅 히트파이프의 열수송 한계를 예측하기 위한 이론적 해석을 수행하였다. 히트파이프의 직경은 8mm이고 작동유체는 물을 사용하였다 250메쉬 조건에서, 각각의 유효 모세관 반경(r$_{c}$ ), 기공률($\varepsilon$), 투과율(K)을 토대로 작동온도와 윅 두께 그러고 경사각에 따른 모세관압력과 열 수송 한계, 열 저항을 분석하였다. 작동온도가 높고 윅 두께가 증가할수록 모세관한계가 높아졌으며, 대체로 소결윅이 스크린적보다 높은 열수송 한계를 나타냈다. 스크린윅의 열저항이 소결윅보다 높았으며, 두 가지 모두 윅 두께가 증가함에 따라 열저항이 선형적으로 상승하였다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
• /
• pp.77-82
• /
• 1996

This paper is concerned with how to utilize kinematic redundancy to reconstruct the inverse kinematic solution which is not attainable due to hardware limitations. By analyzing the error due to hardware limitations, we are to show that the recoverability of limitation reduces to the solvability of a reconstruction equation under the feasibility condition. It will be next shown that the reconstruction equation is solvable if the configuration is not a joint-limit singularity. The reconstruction method will be proposed based on the geometrical analysis of recoverability of hardware limitations. The method has the feature that no task motion error is induced by the hardware limitations while minimizing a possible null motion error, under the recoverability assumed.