• Nuclear Engineering and Technology
• /
• 제48권1호
• /
• pp.129-143
• /
• 2016

Sometimes, we need or try to figure out somebody's thoughts from his or her behaviors such as eye movement, facial expression, gestures, and motions. In safety-critical and complex systems such as nuclear power plants, the inference of operators' thoughts (understanding or diagnosis of a current situation) might provide a lot of opportunities for useful applications, such as development of an improved operator training program, a new type of operator support system, and human performance measures for human factor validation. In this experimental study, a novel method for inference of an operator's thoughts from his or her eye movement data is proposed and evaluated with a nuclear power plant simulator. In the experiments, about 80% of operators' thoughts can be inferred correctly using the proposed method.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
• /
• pp.795-798
• /
• 1997

• 산업공학
• /
• 제13권4호
• /
• pp.751-758
• /
• 2000

Situation awareness is defined as a person's perception of the elements of the environment within a volume of time and space, the comprehension of their meaning and the projection of their status in the near future. Situation awareness is important in attempting to evaluate human behavior in operating complex systems such as aircraft, air traffic control, and nuclear power plant systems. From the literatures this study reviews the relationship between situation awareness and numerous individual, system and environmental factors, and also reviews the methodologies for the empirical measurement of situation awareness applicable to Korea Next Generation Reactor (KNGR) design project. Attention, working memory, workload, stress, system complexity, and automation are presented as critical factors limiting operator's situation awareness. Mental models and goal-directed behavior are hypothesized as important mechanisms overcoming these limits. This study summarized hypothesized guidelines for interface design to improve situation awareness of reactor operators. Some of the guidelines should be tested in the KNGR evaluation experiments in the future.

• Nuclear Engineering and Technology
• /
• 제41권3호
• /
• pp.247-270
• /
• 2009

This paper reviews studies on information searching behavior in process control systems and discusses some implications learned from previous studies for use in human factors studies on nuclear power plants (NPPs) main control rooms (MCRs). Information searching behavior in NPPs depends on expectancy, value, salience, and effort. The first quantitative scanning model developed by Senders for instrument panel monitoring considered bandwidth (change rate) of instruments as a determining factor in scanning behavior. Senders' model was subsequently elaborated by other researchers to account for value in addition to bandwidth. There is also another type of model based on the operator's situation awareness (SA) which has been developed for NPP application. In these SA-based models, situation-event relations or rules on system dynamics are considered the most significant factor forming expectancy. From the review of previous studies it is recommended that, for NPP application, (1) a set of symptomatic information sources including both changed and unchanged symptoms should be considered along with bandwidth as determining factors governing information searching (or visual sampling) behavior; (2) both data-driven monitoring and knowledge-driven monitoring should be considered and balanced in a systematic way; (3) sound models describing mechanisms of cognitive activities during information searching tasks should be developed so as to bridge studies on information searching behavior and design improvement in HMI; (4) the attention-situation awareness (A-SA) modeling approach should be recognized as a promising approach to be examined further; and (5) information displays should be expected to have totally different characteristics in advanced control rooms. Hence much attention should be devoted to information searching behavior including human-machine interface (HMI) design and human cognitive processes.

• 대한전자공학회논문지SP
• /
• 제38권6호
• /
• pp.640-647
• /
• 2001

본 논문에서는 BLU(back light unit) 검사에 적합하도록 잡음에 강건한 일반화 대칭 변환을 주목 연산자로 제안하여 적용함으로써 형태와 크기 및 명도가 다양한 BLU 얼룩들을 효과적으로 검출하였다. 제안한 주목 연산자는 두 화소 명도변화의 크기와 대칭성뿐만 아니라 그 방사(radial)방향의 수렴 및 발산 극성도 반영시켜 잡음이나 불규칙한 배경영상의 양극성 대칭도 누적을 상쇄시킴으로써 명도분포가 일정치 않고 복잡한 무늬의 배경을 갖는 BLU 특유의 검사영상으로부터 얼룩만을 효과적으로 검출할 수 있도록 하였다. CCD 카메라로 입력된 고해상도의 BLU 검사영상에 대해 실험하여 BLU 얼룩 검사에 효과적으로 활용할 수 있음을 확인하였다.

• 대한수학회논문집
• /
• 제9권4호
• /
• pp.917-926
• /
• 1994

Let ($M, G_M, F$) be a (p+q)-dimensional Riemannian manifold with a foliation F of codimension q and a bundle-like metric $g_M$ with respect to F ([9]). Aside from the Laplacian $\bigtriangleup_g$ associated to the metric g, there is another differnetial operator, the Jacobi operator $J_D$, which is a second order elliptic operator acting on sections of the normal bundle. Its spectrum isdiscrete as a consequence of the compactness of M. The study of the spectrum of $\bigtriangleup_g$ acting on functions or forms has attracted a lot of attention. In this point of view, the present authors [7] have studied the spectrum of the Laplacian and the curvature of a compact orientable cosymplectic manifold. On the other hand, S. Nishikawa, Ph. Tondeur and L. Vanhecke [6] studied the spectral geometry for Riemannian foliations. The purpose of the present paper is to study the relation between two spectra and the transversal geometry of cosymplectic foliations. We shall be in $C^\infty$-category. Manifolds are assumed to be connected.

• Nuclear Engineering and Technology
• /
• 제54권4호
• /
• pp.1261-1270
• /
• 2022

This study was conducted to investigate the possibility of using gaze entropy to evaluate an operator's situation awareness in an emergency accident situation of a nuclear power plant. Gaze entropy can be an effective measure for evaluating an operator's situation awareness at a nuclear power plant because it can express gaze movement as a single comprehensive number. In order to determine the relationship between situation awareness and gaze entropy for an emergency accident situation of a nuclear power plant, an experiment was conducted to measure situation awareness and gaze entropy using simulators created for emergency accident situations LOCA, SGTR, SLB, and LOV. The experiment was to judge the accident situation of nuclear power plants presented in the simulator. The results showed that situation awareness and Shannon, dwell time, and Markov entropy had a significant negative correlation, while visual attention entropy (VAE) did not show any significant correlation with situation awareness. The results determined that Shannon entropy, dwell time entropy, and Markov entropy could be used as measures to evaluate situation awareness.

• Nuclear Engineering and Technology
• /
• 제40권4호
• /
• pp.251-254
• /
• 2008

Issues and themes concerned with nuclear power plant uprating are examined. Attention is brought to the fact that many candidate nuclear power plants for uprating have anyway been operated below their rated power for a significant part of their operating life. The key issues remain safety and reliability in operation at all times, irrespective of the nuclear power plant's chronological or design age or power rating. The effects of power uprates are discussed in terms of material aspects and expected demands on the systems, structures and components. The impact on operation and maintenance methods is indicated in terms of changes to the ageing surveillance programmes. Attention is brought to the necessity checking or revising operator actions after power up-rating has been implemented.

• 전기학회논문지
• /
• 제65권7호
• /
• pp.1161-1168
• /
• 2016

Battery energy storage system(BESS) attract the attention of the power system operators with its fast response to a disturbance in spite of its limited energy capacity. This paper proposes the operating method of BESS for following the Automatic Generation Control(AGC) frequency control which is centrally distributed by a system operator. As BESS needs to just meet the control requirement from the system operator, it should be able to properly manage the state of charge(SOC) of BESS to be available to control signal. For doing these, the proposed method distributes the control requirement to available batteries in proportion to its SOC. In addition, unavailable batteries are controlled to recover the SOC to an appropriate range, and the recovering power is supplied by available batteries meeting the control requirement. Moreover, the proposed method manages the efficiency of power conversion system (PCS) by limiting the number of PCS to be assigned for the low control requirement. Finally, the case studies are carried out to verify the effectiveness of proposed strategy.

• 품질경영학회지
• /
• 제26권1호
• /
• pp.108-125
• /
• 1998

The EWMA(Exponentially Weighted Moving Average) has recently received a great deal of attention in the quality control literature as a process monitoring tool on the shop floor of manufacturing industires, since it is easy to plot, to interpret, and its control limits are easy to obtain. Most a, pp.ications of the EWMA for process monitoring have concentrated on the problem of detecting shifts of a process mean and a process standard deviation with ARL(Average Run Length) properties. But there may be the necessity of controlling linearity on product quality such as the correlation coefficient to the process operator. Control managers may want to protect the increase of a process correlation coefficient value, such as 0, between two variables of interest. However, there are few studies concerned on this part. Therefore, we propose EWMA models for a process correlation coefficient using two transformed statistics, T-statistic and (Fisher's) Z-statistic. We also present some results of simulation by SAS/IML and compare two models.