Introducing artificial depth cues to improve task performance in ITER maintenance actions

NARCIS (Netherlands)

Heemskerk, C.J.M.; Eendebak, P.T.; Schropp, G.Y.R.; Hermes, H.V.; Elzendoorn, B.S.Q.; Magielsen, A.J.

2013-01-01

Maintenance operations on ITER tokamak components will be largely performed by remote handling. In previous work it was shown that representative maintenance tasks could be performed significantly faster with direct visual feedback than with camera feedback. In post-test interviews, operators

An approach to integrating surveillance and maintenance tasks to prevent the dominant failure causes of critical components

International Nuclear Information System (INIS)

Martorell, S.; Munoz, A.; Serradell, V.

1995-01-01

Surveillance requirements and maintenance activities in a nuclear power plant aim to preserve components' inherent reliability. Up to now, predictive and preventive maintenance mainly concerned plant staff, but the US Nuclear Regulatory Commission Maintenance Rule released in July 1991 will have significant impact on how nuclear power plants perform and document this maintenance. Reliability Centered Maintenance (RCM) is a systematic methodology to establish maintenance tasks for critical components in plant with a high degree of compliance with the goals of the Rule. RCM pursues the identification of applicable and efficient tasks to prevent these components from developing their dominant failure causes, and, in turn, towards achieving proper levels of components availability with low cost. In this paper, we present an approach for identifying the most suitable set of tasks to achieve this goal, which involves the integration of maintenance activities and surveillance requirements for each critical component based on the unavailability and cost associated with each individual task which is performed on it

Integrated Technical Information for the Air Logistics Center: Enhancing Maintenance Technician Task Performance

National Research Council Canada - National Science Library

Mitta, Deborah

1998-01-01

This technical paper documents the final results of an analysis of the task environment under which depot maintenance technicians perform their jobs--specifically, programmed depot maintenance (PDM) for F-15 aircraft...

Study on the methodology for predicting and preventing errors to improve reliability of maintenance task in nuclear power plant

International Nuclear Information System (INIS)

Hanafusa, Hidemitsu; Iwaki, Toshio; Embrey, D.

2000-01-01

The objective of this study was to develop and effective methodology for predicting and preventing errors in nuclear power plant maintenance tasks. A method was established by which chief maintenance personnel can predict and reduce errors when reviewing the maintenance procedures and while referring to maintenance supporting systems and methods in other industries including aviation and chemical plant industries. The method involves the following seven steps: 1. Identification of maintenance tasks. 2. Specification of important tasks affecting safety. 3. Assessment of human errors occurring during important tasks. 4. Identification of Performance Degrading Factors. 5. Dividing important tasks into sub-tasks. 6. Extraction of errors using Predictive Human Error Analysis (PHEA). 7. Development of strategies for reducing errors and for recovering from errors. By way of a trial, this method was applied to the pump maintenance procedure in nuclear power plants. This method is believed to be capable of identifying the expected errors in important tasks and supporting the development of error reduction measures. By applying this method, the number of accidents resulting form human errors during maintenance can be reduced. Moreover, the maintenance support base using computers was developed. (author)

The Neural Mechanisms Underlying Internally and Externally Guided Task Selection

Science.gov (United States)

Orr, Joseph M.; Banich, Marie T.

2013-01-01

While some prior work suggests that medial prefrontal cortex (MFC) regions mediate freely chosen actions, other work suggests that the lateral frontal pole (LFP) is responsible for control of abstract, internal goals. The present study uses fMRI to determine whether the voluntary selection of a task in pursuit of an overall goal relies on MFC regions or the LFP. To do so, we used a modified voluntary task switching (VTS) paradigm, in which participants choose an individual task to perform on each trial (i.e., a subgoal), under instructions to perform the tasks equally often and in a random order (i.e. the overall goal). In conjunction, we examined patterns of activation in the face of irrelevant, but task-related external stimuli that might nonetheless influence task selection. While there was some evidence that the MFC was involved in voluntary task selection, we found that the LFP and anterior insula (AI) were crucial to task selection in the pursuit of an overall goal. In addition, activation of the LFP and AI increased in the face of environmental stimuli that might serve as an interfering or conflicting external bias on voluntary task choice. These findings suggest that the LFP supports task selection according to abstract, internal goals, and leaves open the possibility that MFC may guide action selection in situations lacking in such top-down biases. As such, the current study represents a critical step towards understanding the neural underpinnings of how tasks are selected voluntarily to enable an overarching goal. PMID:23994316

Assistance tools for generic definition of ITER maintenance tasks and scenarios in advanced supervisory control systems

International Nuclear Information System (INIS)

Zieba, Stéphane; Russotto, François-Xavier; Da Silva Simoes, Max; Measson, Yvan

2013-01-01

Highlights: ► Improve supervisory control systems for ITER in-vessel and hot cell maintenance. ► Optimize remote handling operations effectiveness, reliability and safety. ► Provide a generic description of the maintenance tasks and scenarios. ► Development of context-based assistances for operators and supervisor. ► Improvement of operator's situation awareness. -- Abstract: This paper concerns the improvement of supervisory control systems in the context of remote handling for the maintenance tasks in ITER. This work aims at providing a single formalism and tools to define in a generic way the ITER maintenance tasks and scenarios for in-vessel and hot cell operations. A three-layered approach is proposed to model these tasks and scenarios. Physical actions are defined for the scene elements. From these physical actions, behaviours are defined to represent high-level functionalities. Finally, interaction modes define the way that behaviours are achieved in terms of human–machine interactions. Case study concerning the blanket maintenance procedure is discussed concerning the contributions of the descriptive model and the context-based assistances to the activities of supervisory control

Task analysis of human-in-the-loop tele-operated maintenance: What can be learned from JET?

International Nuclear Information System (INIS)

Boessenkool, H.; Thomas, J.; Heemskerk, C.J.M.; Baar, M.R. de; Steinbuch, M.; Abbink, D.A.

2014-01-01

Highlights: •Maintenance task execution at JET was analyzed to guide improvements for ITER. •A large variation in task duration was found for various operator experience levels. •Results indicate significant room for improvement for tele-operated performance. •Improvent of visual feedback and artificial guiding forces was considered promising. -- Abstract: Remote maintenance will determine the available uptime of future fusion plants such as ITER. Experience at predecessor JET showed that a human-in-the-loop tele-operated approach is crucial, although this approach entails drawbacks such as the unavoidable extensive operator training and relatively long execution times. These drawbacks are common knowledge, but little quantitative research is available to guide improvements (such as improved training methods, or active operator support systems). The aim of this paper is to identify the key areas for further improvement of tele-operated maintenance. This is achieved by a detailed task analysis based on recent maintenance at JET, using task logbooks and video data as well as interviews with experienced master–slave operators. The resulting task analysis shows the (sub)tasks that were most time-consuming and shows a large variance in time performance within operators, but also substantial differences between qualified operators with different levels of experience. The operator interviews indicate that intuitive (virtual) visual feedback and artificial (guiding) forces are promising directions for improvement. The results found in this study will be used for future research and development activities focusing on haptic guiding strategies, with the aim to further design and optimize RH maintenance systems for ITER and beyond

Introducing artificial depth cues to improve task performance in ITER maintenance actions

International Nuclear Information System (INIS)

Heemskerk, C.J.M.; Eendebak, P.T.; Schropp, G.Y.R.; Hermes, H.V.; Elzendoorn, B.S.Q.; Magielsen, A.J.

2013-01-01

Highlights: ► Operators regard lack of 3D perception as primary factor hindering remote maintenance. ► Promising techniques to improve depth perception are depth gauges and stereo vision. ► First experiment shows artificial depth gauges need to be designed with care. ► Second experiment shows that stereo vision improves task performance significantly. -- Abstract: Maintenance operations on ITER tokamak components will be largely performed by remote handling. In previous work it was shown that representative maintenance tasks could be performed significantly faster with direct visual feedback than with camera feedback. In post-test interviews, operators indicated that they regarded the lack of 3D perception as the primary factor hindering their performance. This paper discusses various techniques to improve depth perception in teleoperation, including stereo vision, head tracking, virtual camera views and depth gauges. The most promising techniques were tested. Performance metrics included time-to-complete, path analysis and operator work-load. In a first experiment, artificial depth gauges views were tested in a 1:1 scale hardware testbed with mechanical master-slave manipulators handled by experienced operators. Robust real-time image processing was achieved with marker-based objects. The simple depth gauge and graphical overlay did not significantly improve task performance. Operators commented on their view of the task being “obstructed” by the graphical overlay, and the depth gauge was judged not very informative. In a second experiment, real time tracking was combined with VR display including stereo and head tracking. While stereo was found to improve the task performance significantly over the 1 camera (mono) condition, head tracking unexpectedly did not

Introducing artificial depth cues to improve task performance in ITER maintenance actions

Energy Technology Data Exchange (ETDEWEB)

Heemskerk, C.J.M., E-mail: c.heemskerk@heemskerk-innovative.nl [Heemskerk Innovative Technology, Sassenheim (Netherlands); Eendebak, P.T. [TNO Netherlands Organisation for Applied Scientific Research (Netherlands); Schropp, G.Y.R. [Heemskerk Innovative Technology, Sassenheim (Netherlands); Hermes, H.V. [TU Eindhoven (Netherlands); Elzendoorn, B.S.Q. [FOM Institute DIFFER (Dutch Institute for Fundamental Energy Research), Association EURATOM-FOM, Partner in the Trilateral Euregio Cluster, P.O. Box 1207, 3430 BE Nieuwegein (Netherlands); Magielsen, A.J. [NRG, P.O. Box 25, 1755 ZG Petten (Netherlands)

2013-10-15

Highlights: ► Operators regard lack of 3D perception as primary factor hindering remote maintenance. ► Promising techniques to improve depth perception are depth gauges and stereo vision. ► First experiment shows artificial depth gauges need to be designed with care. ► Second experiment shows that stereo vision improves task performance significantly. -- Abstract: Maintenance operations on ITER tokamak components will be largely performed by remote handling. In previous work it was shown that representative maintenance tasks could be performed significantly faster with direct visual feedback than with camera feedback. In post-test interviews, operators indicated that they regarded the lack of 3D perception as the primary factor hindering their performance. This paper discusses various techniques to improve depth perception in teleoperation, including stereo vision, head tracking, virtual camera views and depth gauges. The most promising techniques were tested. Performance metrics included time-to-complete, path analysis and operator work-load. In a first experiment, artificial depth gauges views were tested in a 1:1 scale hardware testbed with mechanical master-slave manipulators handled by experienced operators. Robust real-time image processing was achieved with marker-based objects. The simple depth gauge and graphical overlay did not significantly improve task performance. Operators commented on their view of the task being “obstructed” by the graphical overlay, and the depth gauge was judged not very informative. In a second experiment, real time tracking was combined with VR display including stereo and head tracking. While stereo was found to improve the task performance significantly over the 1 camera (mono) condition, head tracking unexpectedly did not.

Scheduling a maintenance activity under skills constraints to minimize total weighted tardiness and late tasks

Directory of Open Access Journals (Sweden)

Djalal Hedjazi

2015-04-01

Full Text Available Skill management is a key factor in improving effectiveness of industrial companies, notably their maintenance services. The problem considered in this paper concerns scheduling of maintenance tasks under resource (maintenance teams constraints. This problem is generally known as unrelated parallel machine scheduling. We consider the problem with a both objectives of minimizing total weighted tardiness (TWT and number of tardiness tasks. Our interest is focused particularly on solving this problem under skill constraints, which each resource has a skill level. So, we propose a new efficient heuristic to obtain an approximate solution for this NP-hard problem and demonstrate his effectiveness through computational experiments. This heuristic is designed for implementation in a static maintenance scheduling problem (with unequal release dates, processing times and resource skills, while minimizing objective functions aforementioned.

Optimizing preventive maintenance with maintenance templates

International Nuclear Information System (INIS)

Dozier, I.J.

1996-01-01

Rising operating costs has caused maintenance professionals to rethink their strategy for preventive maintenance (PM) programs. Maintenance Templates are pre-engineered PM task recommendations for a component type based on application of the component. Development of the maintenance template considers the dominant failure cause of the component and the type of preventive maintenance that can predict or prevent the failure from occurring. Maintenance template development also attempts to replace fixed frequency tasks with condition monitoring tasks such as vibration analysis or thermography. For those components that have fixed frequency PM intervals, consideration is given to the maintenance drivers such as criticality, environment and usage. This helps to maximize the PM frequency intervals and maximize the component availability. Maintenance Templates have been used at PECO Energy's Limerick Generating Station during the Reliability Centered Maintenance (RCM) Process to optimize their PM program. This paper describes the development and uses of the maintenance templates

Evaluating Virtual Reality and Augmented Reality Training for Industrial Maintenance and Assembly Tasks

Science.gov (United States)

Gavish, Nirit; Gutiérrez, Teresa; Webel, Sabine; Rodríguez, Jorge; Peveri, Matteo; Bockholt, Uli; Tecchia, Franco

2015-01-01

The current study evaluated the use of virtual reality (VR) and augmented reality (AR) platforms, developed within the scope of the SKILLS Integrated Project, for industrial maintenance and assembly (IMA) tasks training. VR and AR systems are now widely regarded as promising training platforms for complex and highly demanding IMA tasks. However,…

Parietal EEG alpha suppression time of memory retrieval reflects memory load while the alpha power of memory maintenance is a composite of the visual process according to simultaneous and successive Sternberg memory tasks.

Science.gov (United States)

Okuhata, Shiho; Kusanagi, Takuya; Kobayashi, Tetsuo

2013-10-25

The present study investigated EEG alpha activity during visual Sternberg memory tasks using two different stimulus presentation modes to elucidate how the presentation mode affected parietal alpha activity. EEGs were recorded from 10 healthy adults during the Sternberg tasks in which memory items were presented simultaneously and successively. EEG power and suppression time (ST) in the alpha band (8-13Hz) were computed for the memory maintenance and retrieval phases. The alpha activity differed according to the presentation mode during the maintenance phase but not during the retrieval phase. Results indicated that parietal alpha power recorded during the maintenance phase did not reflect the memory load alone. In contrast, ST during the retrieval phase increased with the memory load for both presentation modes, indicating a serial memory scanning process, regardless of the presentation mode. These results indicate that there was a dynamic transition in the memory process from the maintenance phase, which was sensitive to external factors, toward the retrieval phase, during which the process converged on the sequential scanning process, the Sternberg task essentially required. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Latent human error analysis and efficient improvement strategies by fuzzy TOPSIS in aviation maintenance tasks.

Science.gov (United States)

Chiu, Ming-Chuan; Hsieh, Min-Chih

2016-05-01

The purposes of this study were to develop a latent human error analysis process, to explore the factors of latent human error in aviation maintenance tasks, and to provide an efficient improvement strategy for addressing those errors. First, we used HFACS and RCA to define the error factors related to aviation maintenance tasks. Fuzzy TOPSIS with four criteria was applied to evaluate the error factors. Results show that 1) adverse physiological states, 2) physical/mental limitations, and 3) coordination, communication, and planning are the factors related to airline maintenance tasks that could be addressed easily and efficiently. This research establishes a new analytic process for investigating latent human error and provides a strategy for analyzing human error using fuzzy TOPSIS. Our analysis process complements shortages in existing methodologies by incorporating improvement efficiency, and it enhances the depth and broadness of human error analysis methodology. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Operation and maintenance in the cooling and ventilation group

OpenAIRE

Bangert, N

2003-01-01

A core team of CERN staff is running the daily operations of the cooling and ventilation equipment at CERN, thus assuring multiple interfaces such as constant contact with the users of existing installations, the project leaders for new installations and intern-divisional communication. As support of this team, re-tendered contracts with external companies for the maintenance and operational tasks have been put into place multiple years ago. Higherlevel maintenance continues to be entrusted t...

The effect of the external regulator's absence on children's speech use, manifested self-regulation, and task performance during learning tasks

NARCIS (Netherlands)

Agina, Adel M.; Agina, Adel Masaud; Kommers, Petrus A.M.; Steehouder, M.F.

2011-01-01

The present study was conducted to explore the effect of the absence of the external regulators on children’s use of speech (private/social), task performance, and self-regulation during learning tasks. A novel methodology was employed through a computer-based learning environment that proposed

A preventive maintenance policy based on dependent two-stage deterioration and external shocks

International Nuclear Information System (INIS)

Yang, Li; Ma, Xiaobing; Peng, Rui; Zhai, Qingqing; Zhao, Yu

2017-01-01

This paper proposes a preventive maintenance policy for a single-unit system whose failure has two competing and dependent causes, i.e., internal deterioration and sudden shocks. The internal failure process is divided into two stages, i.e. normal and defective. Shocks arrive according to a non-homogeneous Poisson process (NHPP), leading to the failure of the system immediately. The occurrence rate of a shock is affected by the state of the system. Both an age-based replacement and finite number of periodic inspections are schemed simultaneously to deal with the competing failures. The objective of this study is to determine the optimal preventive replacement interval, inspection interval and number of inspections such that the expected cost per unit time is minimized. A case study on oil pipeline maintenance is presented to illustrate the maintenance policy. - Highlights: • A maintenance model based on two-stage deterioration and sudden shocks is developed. • The impact of internal system state on external shock process is studied. • A new preventive maintenance strategy combining age-based replacements and periodic inspections is proposed. • Postponed replacement of a defective system is provided by restricting the number of inspections.

Quality upgrading and cost reducing effects of using an operation control system for performance of maintenance tasks

International Nuclear Information System (INIS)

Ramler, K.

1996-01-01

According to available results, the use of an operation control system has come up to expections with respect to a quality enhancement of maintenance work. The tasks are performed more safely and there is more insight into the processes. so that, as indirect results, cost savings and rationalisation effects are to be expected. However, the cost savings achieved through the operation control system for maintenance tasks will remain modest. The truly cost-effective optimisation potentials in the maintenance area primarily consist in a reduction of preventive measures to the required scope, i.e reduction of the envisaged quantity of processes for maintenance and recurrent inspection. In order to extend savings to the organisational level, with respect to personnel expenditure, by DP supported maintenance planning, a suitable optimisation of the organisational structure and personnel employment is inevitable, because otherwise the rationalisation potentials will remain utopia. (orig.) [de

A condition-based maintenance of a dependent degradation-threshold-shock model in a system with multiple degradation processes

International Nuclear Information System (INIS)

Caballé, N.C.; Castro, I.T.; Pérez, C.J.; Lanza-Gutiérrez, J.M.

2015-01-01

This paper proposes a condition-based maintenance strategy for a system subject to two dependent causes of failure: degradation and sudden shocks. The internal degradation is reflected by the presence of multiple degradation processes in the system. Degradation processes start at random times following a Non-homogeneous Poisson process and their growths are modelled by using a gamma process. When the deterioration level of a degradation process exceeds a predetermined value, we assume that a degradation failure occurs. Furthermore, the system is subject to sudden shocks that arrive at the system following a Doubly Stochastic Poisson Process. A sudden shock provokes the total breakdown of the system. Thus, the state of the system is evaluated at inspection times and different maintenance tasks can be carried out. If the system is still working at an inspection time, a preventive maintenance task is performed if the deterioration level of a degradation process exceeds a certain threshold. A corrective maintenance task is performed if the system is down at an inspection time. A preventive (corrective) maintenance task implies the replacement of the system by a new one. Under this maintenance strategy, the expected cost rate function is obtained. A numerical example illustrates the analytical results. - Highlights: • A condition-based maintenance model is proposed. • Two dependent causes of failure are considered: deterioration and external shocks. • Deterioration is given by multiple degradation processes growing by a gamma process. • The initiation of degradation processes follows a Non-homogeneous Poisson process. • External shocks arrive at the system by using a Doubly Stochastic Poisson Process

Optimization of perceptual learning: effects of task difficulty and external noise in older adults.

Science.gov (United States)

DeLoss, Denton J; Watanabe, Takeo; Andersen, George J

2014-06-01

Previous research has shown a wide array of age-related declines in vision. The current study examined the effects of perceptual learning (PL), external noise, and task difficulty in fine orientation discrimination with older individuals (mean age 71.73, range 65-91). Thirty-two older subjects participated in seven 1.5-h sessions conducted on separate days over a three-week period. A two-alternative forced choice procedure was used in discriminating the orientation of Gabor patches. Four training groups were examined in which the standard orientations for training were either easy or difficult and included either external noise (additive Gaussian noise) or no external noise. In addition, the transfer to an untrained orientation and noise levels were examined. An analysis of the four groups prior to training indicated no significant differences between the groups. An analysis of the change in performance post-training indicated that the degree of learning was related to task difficulty and the presence of external noise during training. In addition, measurements of pupil diameter indicated that changes in orientation discrimination were not associated with changes in retinal illuminance. These results suggest that task difficulty and training in noise are factors important for optimizing the effects of training among older individuals. Copyright © 2013 Elsevier B.V. All rights reserved.

Maintenance of EDF nuclear power plants and servicing companies. Progress report

International Nuclear Information System (INIS)

Baize, Jean-Marc; Reveillon, Sylvie

1997-01-01

French Electricity Company (EDF - Electricite de France) and the associated servicing companies, engaged in maintenance partnership from 1991, reinforce and expand their policy by undersigning a progress charter, to cope with the safety and nuclear sector competition issues. This charter stipulates the mutual engagements in the following sectors: 1. Transparency in calling for servicing; 2. Development of the intervenors' professionalism; 3. Improvement in forecasting activity tasks; 4. Radioprotection; 5. Safety and working conditions. The 55 reactors of the EDF nuclear stock are stopped annually for around 6 weeks for refueling. On this occasion the essential maintenance works necessary to ensure the optimal safety of the installations are carried out. The maintenance requires the intervention of 30,000 employees, 10,000 EDF agents and 20,000 external intervenors and represents an amount of 14 million working hours. The full maintenance expenses amounts up to 11 billion FF in 1996, 6 billion of which are assigned to external companies

Can Dual Task Walking Improve in Parkinson's Disease After External Focus of Attention Exercise? A Single Blind Randomized Controlled Trial.

Science.gov (United States)

Beck, Eric N; Intzandt, Brittany N; Almeida, Quincy J

2018-01-01

It may be possible to use attention-based exercise to decrease demands associated with walking in Parkinson's disease (PD), and thus improve dual task walking ability. For example, an external focus of attention (focusing on the effect of an action on the environment) may recruit automatic control processes degenerated in PD, whereas an internal focus (limb movement) may recruit conscious (nonautomatic) control processes. Thus, we aimed to investigate how externally and internally focused exercise influences dual task walking and symptom severity in PD. Forty-seven participants with PD were randomized to either an Externally (n = 24) or Internally (n = 23) focused group and completed 33 one-hour attention-based exercise sessions over 11 weeks. In addition, 16 participants were part of a control group. Before, after, and 8 weeks following the program (pre/post/washout), gait patterns were measured during single and dual task walking (digit-monitoring task, ie, walking while counting numbers announced by an audio-track), and symptom severity (UPDRS-III) was assessed ON and OFF dopamine replacement. Pairwise comparisons (95% confidence intervals [CIs]) and repeated-measures analyses of variance were conducted. Pre to post: Dual task step time decreased in the external group (Δ = 0.02 seconds, CI 0.01-0.04). Dual task step length (Δ = 2.3 cm, CI 0.86-3.75) and velocity (Δ = 4.5 cm/s, CI 0.59-8.48) decreased (became worse) in the internal group. UPDRS-III scores (ON and OFF) decreased (improved) in only the External group. Pre to washout: Dual task step time ( P = .005) and percentage in double support ( P = .014) significantly decreased (improved) in both exercise groups, although only the internal group increased error on the secondary counting task (ie, more errors monitoring numbers). UPDRS-III scores in both exercise groups significantly decreased ( P = .001). Since dual task walking improvements were found immediately, and 8 weeks after the cessation of an

Human factor analysis and preventive countermeasures of maintenance in nuclear power plant

International Nuclear Information System (INIS)

Zhang Li; Hu Chao

2008-01-01

Based on the human error analysis theory and the characteristics of maintenance in a nuclear power plant, human factors of maintenance in NPP are divided into three different areas: human, technology, and organization, in which human refers to the individual factors, mainly including psychological quality, physiological characteristic, state of health, knowledge, skill level, and interpersonal relationship. Technology includes the maintenance technology, maintenance strategy, maintenance tool, maintenance interface, maintenance regulation, and work environment. Organization includes task arrangement, information communication, training, personnel external environment, team construction, and leadership. The analysis also reveals that the organization factors, which can indirectly influence personnel performance, are the primary initiators of human error. Based on these, some countermeasures are brought forward in order to reduce human errors. (authors)

Factor analysis for imperfect maintenance planning at nuclear power plants by cognitive task analysis

International Nuclear Information System (INIS)

Takagawa, Kenichi; Iida, Hiroyasu

2011-01-01

Imperfect maintenance planning was frequently identified in domestic nuclear power plants. To prevent such an event, we analyzed causal factors in maintenance planning stages and showed the directionality of countermeasures in this study. There is a pragmatic limit in finding the causal factors from the items based on report descriptions. Therefore, the idea of the systemic accident model, which is used to monitor the performance variability in normal circumstances, is taken as a new concept instead of investigating negative factors. As an actual method for analyzing usual activities, cognitive task analysis (CTA) was applied. Persons who experienced various maintenance activities at one electric power company were interviewed about sources related to decision making during maintenance planning, and then usual factors affecting planning were extracted as performance variability factors. The tendency of domestic events was analyzed using the classification item of those factors, and the directionality of countermeasures was shown. The following are critical for preventing imperfect maintenance planning: the persons in charge should fully understand the situation of the equipment for which they are responsible in the work planning and maintenance evaluation stages, and they should definitely understand, for example, the maintenance bases of that equipment. (author)

Improving human performance in maintenance personnel

International Nuclear Information System (INIS)

Gonzalez Anez, Francisco; Agueero Agueero, Jorge

2010-01-01

The continuous evolution and improvement of safety-related processes has included the analysis, design and development of training plans for the qualification of maintenance nuclear power plant personnel. In this respect, the international references in this area recommend the establishment of systematic qualification programmes for personnel performing functions or carrying out safety related tasks. Maintenance personnel qualification processes have improved significantly, and training plans have been designed and developed based on Systematic Approach to Training methodology to each job position. These improvements have been clearly reflected in recent training programmes with new training material and training facilities focused not only on developing technical knowledge and skills but also on improving attitudes and safety culture. The objectives of maintenance training facilities such as laboratories, mock-ups real an virtual, hydraulic loops, field simulators and other training material to be used in the maintenance training centre are to cover training necessities for initial and continuous qualification. Evidently, all these improvements made in the qualification of plant personnel should be extended to include supplemental personnel (external or contracted) performing safety-related tasks. The supplemental personnel constitute a very spread group, covering the performance of multiple activities entailing different levels of responsibility. Some of these activities are performed permanently at the plant, while others are occasional or sporadic. In order to establish qualification requirements for these supplemental workers, it is recommended to establish a rigorous analysis of job positions and tasks. The objective will be to identify the qualification requirements to assure competence and safety. (authors)

Identification of tasks of maintenance centered in the reliability; Identificacion de tareas de mantenimiento centrado en la confiabilidad

Energy Technology Data Exchange (ETDEWEB)

Torres V, A.; Rivero O, J.J. [Dpto. Ingenieria Nuclear, Instituto Superior de Tecnologias y Ciencias Aplicadas, Ave. Salvador Allende y Luaces, Quinta de los Molinos, Plaza, Ciudad Habana (Cuba)]. e-mail: atorres@fctn.isctn.edu.cu

2004-07-01

The methodology of Reliability Centered Maintenance (RCM) it has become, after the discovery of their advantages, an objective of many industrial facilities to optimize their maintenance. However, diverse subjective factors affect the determination of the parameters (technical of predictive to apply and times among interventions) that characterize the tasks of RCM. A method to determine the monitoring tasks at condition and the times more recommended for to apply the monitoring by time and the search of faults, with focus in system. This methodology has been computerized inside the code MOSEG Win Ver 1.0. The same has been applied with success to the determination of tasks of RCM in industrial objectives. (Author)

The Development of Memory Maintenance: Children's Use of Phonological Rehearsal and Attentional Refreshment in Working Memory Tasks

Science.gov (United States)

Tam, Helen; Jarrold, Christopher; Baddeley, Alan D.; Sabatos-DeVito, Maura

2010-01-01

Past research suggests that children begin to phonologically rehearse at around 7 years of age. Less is known regarding the development of refreshment, an attention-based maintenance mechanism. Therefore, the use of these two maintenance methods by 6- and 8-year-olds was assessed using memory span tasks that varied in their opportunities for…

Development of a standard methodology for optimizing remote visual display for nuclear maintenance tasks

Science.gov (United States)

Clarke, M. M.; Garin, J.; Prestonanderson, A.

A fuel recycle facility being designed at Oak Ridge National Laboratory involves the Remotex concept: advanced servo-controlled master/slave manipulators, with remote television viewing, will totally replace direct human contact with the radioactive environment. The design of optimal viewing conditions is a critical component of the overall man/machine system. A methodology was developed for optimizing remote visual displays for nuclear maintenance tasks. The usefulness of this approach was demonstrated by preliminary specification of optimal closed circuit TV systems for such tasks.

Analysis of internal and external validity criteria for a computerized visual search task: A pilot study.

Science.gov (United States)

Richard's, María M; Introzzi, Isabel; Zamora, Eliana; Vernucci, Santiago

2017-01-01

Inhibition is one of the main executive functions, because of its fundamental role in cognitive and social development. Given the importance of reliable and computerized measurements to assessment inhibitory performance, this research intends to analyze the internal and external criteria of validity of a computerized conjunction search task, to evaluate the role of perceptual inhibition. A sample of 41 children (21 females and 20 males), aged between 6 and 11 years old (M = 8.49, SD = 1.47), intentionally selected from a private management school of Mar del Plata (Argentina), middle socio-economic level were assessed. The Conjunction Search Task from the TAC Battery, Coding and Symbol Search tasks from Wechsler Intelligence Scale for Children were used. Overall, results allow us to confirm that the perceptual inhibition task form TAC presents solid rates of internal and external validity that make a valid measurement instrument of this process.

Competence within Maintenance

OpenAIRE

Nerland, Annette Smørholm

2010-01-01

Maintenance can be a contributing factor to unwanted events, as well as desired events and states. Human competence can be defined as the ability to perform a specific task, action or function successfully, and is therefore a key factor to proper execution of maintenance tasks. Hence,maintenance will have negative consequences if done wrong, and give positive results when done right. The purpose of this report is to study the many aspects of maintenance competence. Endeavoring to improve ...

Effectiveness of a Play Therapy Intervention on Children's Externalizing and Off-Task Behaviors

Science.gov (United States)

Meany-Walen, Kristin K.; Teeling, Sunny; Davis, Aubrey; Artley, George; Vignovich, Andrea

2017-01-01

Children's externalizing and off-task behaviors are deemed a major concern for elementary teachers and interfere with the classroom learning environment (Abidin & Robinson, 2002; Shillingford-Butler & Theodore, 2013). Children with these behaviors are at risk of falling behind academically and experiencing ongoing behavioral problems…

Functional connectivity supporting the selective maintenance of feature-location binding in visual working memory

Directory of Open Access Journals (Sweden)

Sachiko eTakahama

2014-06-01

Full Text Available Information on an object’s features bound to its location is very important for maintaining object representations in visual working memory. Interactions with dynamic multi-dimensional objects in an external environment require complex cognitive control, including the selective maintenance of feature-location binding. Here, we used event-related functional magnetic resonance imaging to investigate brain activity and functional connectivity related to the maintenance of complex feature-location binding. Participants were required to detect task-relevant changes in feature-location binding between objects defined by color, orientation, and location. We compared a complex binding task requiring complex feature-location binding (color-orientation-location with a simple binding task in which simple feature-location binding, such as color-location, was task-relevant and the other feature was task-irrelevant. Univariate analyses showed that the dorsolateral prefrontal cortex (DLPFC, hippocampus, and frontoparietal network were activated during the maintenance of complex feature-location binding. Functional connectivity analyses indicated cooperation between the inferior precentral sulcus (infPreCS, DLPFC, and hippocampus during the maintenance of complex feature-location binding. In contrast, the connectivity for the spatial updating of simple feature-location binding determined by reanalyzing the data from Takahama et al. (2010 demonstrated that the superior parietal lobule (SPL cooperated with the DLPFC and hippocampus. These results suggest that the connectivity for complex feature-location binding does not simply reflect general memory load and that the DLPFC and hippocampus flexibly modulate the dorsal frontoparietal network, depending on the task requirements, with the infPreCS involved in the maintenance of complex feature-location binding and the SPL involved in the spatial updating of simple feature-location binding.

Development of a standard methodology for optimizing remote visual display for nuclear-maintenance tasks

International Nuclear Information System (INIS)

Clarke, M.M.; Garin, J.; Preston-Anderson, A.

1981-01-01

The aim of the present study is to develop a methodology for optimizing remote viewing systems for a fuel recycle facility (HEF) being designed at Oak Ridge National Laboratory (ORNL). An important feature of this design involves the Remotex concept: advanced servo-controlled master/slave manipulators, with remote television viewing, will totally replace direct human contact with the radioactive environment. Therefore, the design of optimal viewing conditions is a critical component of the overall man/machine system. A methodology has been developed for optimizing remote visual displays for nuclear maintenance tasks. The usefulness of this approach has been demonstrated by preliminary specification of optimal closed circuit TV systems for such tasks

Estimating Maintenance Cost for Web Applications

Directory of Open Access Journals (Sweden)

Ion IVAN

2016-01-01

Full Text Available The current paper tackles the issue of determining a method for estimating maintenance costs for web applications. The current state of research in the field of web application maintenance is summarized and leading theories and results are highlighted. The cost of web maintenance is determined by the number of man-hours invested in maintenance tasks. Web maintenance tasks are categorized into content maintenance and technical maintenance. Research is centered on analyzing technical maintenance tasks. The research hypothesis is formulated on the assumption that the number of man-hours invested in maintenance tasks can be assessed based on the web application’s user interaction level, complexity and content update effort. Data regarding the costs of maintenance tasks is collected from 24 maintenance projects implemented by a web development company that tackles a wide area of web applications. Homogeneity and diversity of collected data is submitted for debate by presenting a sample of the data and depicting the overall size and comprehensive nature of the entire dataset. A set of metrics dedicated to estimating maintenance costs in web applications is defined based on conclusions formulated by analyzing the collected data and the theories and practices dominating the current state of research. Metrics are validated with regards to the initial research hypothesis. Research hypothesis are validated and conclusions are formulated on the topic of estimating the maintenance cost of web applications. The limits of the research process which represented the basis for the current paper are enunciated. Future research topics are submitted for debate.

Generation IV Nuclear Energy Systems Construction Cost Reductions through the Use of Virtual Environments - Task 4 Report: Virtual Mockup Maintenance Task Evaluation

Energy Technology Data Exchange (ETDEWEB)

Timothy Shaw; Anthony Baratta; Vaughn Whisker

2005-02-28

Task 4 report of 3 year DOE NERI-sponsored effort evaluating immersive virtual reality (CAVE) technology for design review, construction planning, and maintenance planning and training for next generation nuclear power plants. Program covers development of full-scale virtual mockups generated from 3D CAD data presented in a CAVE visualization facility. This report focuses on using Full-scale virtual mockups for nuclear power plant training applications.

Generation IV Nuclear Energy Systems Construction Cost Reductions through the Use of Virtual Environments - Task 4 Report: Virtual Mockup Maintenance Task Evaluation

International Nuclear Information System (INIS)

Timothy Shaw; Anthony Baratta; Vaughn Whisker

2005-01-01

Task 4 report of 3 year DOE NERI-sponsored effort evaluating immersive virtual reality (CAVE) technology for design review, construction planning, and maintenance planning and training for next generation nuclear power plants. Program covers development of full-scale virtual mockups generated from 3D CAD data presented in a CAVE visualization facility. This report focuses on using Full-scale virtual mockups for nuclear power plant training applications

Competitive Position of Dependent Passenger Car Maintenance Companies – Influences, Developments and Challenges in the German Market

Directory of Open Access Journals (Sweden)

Werdich Karl

2015-06-01

Full Text Available The presented paper concerns itself with passenger car maintenance companies and their competitiveness. Internal and external influences, change drivers and general changes in the companies and their organisation were identified and analysed. The influence of the development of technology and the diffusion of innovations are highlighted in particular. Under consideration of the competitiveness factors, current and future challenges for the passenger car maintenance companies were worked out. Based on these analyses, future tasks, problem statements and challenges were compiled for passenger car maintenance companies from which other subjects of scientific investigation in area of strategic and economic importance arose.

External exposure dose of car mechanics during the maintenance of the cars from the risk cautionary area

International Nuclear Information System (INIS)

Kawakami, Hiroto; Yamada, Norikazu; Sasaki, Satoru; Kawasaki, Satoru

2011-12-01

At the request of the Local Nuclear Emergency Response Headquarters, JNES has estimated the effective external exposure dose of car mechanics during the maintenance of the cars from the risk cautionary area. JNES investigated the contamination of the cars from the risk cautionary area and of the average cars at Fukushima city cooperated by the Japan Automobile Dealers Association. Data of screed cars by the Local Nuclear Emergency Response Headquarters is also considered in. Effective external exposure dose of car mechanics treating the cars screened with the emergency situation screening level is estimated to be less than 1 mSv/y under the conservative conditions. This result shows that particular health concern isn't necessary for them. (author)

Learner-Centered Instruction (LCI): Volume IV, The Simulated Maintenance Task Environment (SMTE): A Job Specific Simulator.

Science.gov (United States)

Rifkin, Kenneth I.; And Others

The purpose of the simulated maintenance task environment is to provide a means for training and job performance testing of the flight line weapon control systems mechanic/technician for the F-111A aircraft. It provides practice in flight line equipment checkout, troubleshooting, and removal and replacement of line replaceable units in the…

Using the system maintenance datastore to characterize lifetime maintenance for PLiM

International Nuclear Information System (INIS)

Watson, P.; Dam, R.; Nickerson, J.

2004-01-01

A comprehensive Plant Life Management (PLiM) program involves evaluating a large amount of information. For any plant, there are numerous maintenance, surveillance and inspection programs for the important systems, structures and components. There is extensive industry experience on component failure modes, degradation mechanisms and recommended maintenance practices. This information forms the basis of the aging assessment work, through which improvements to these plant programs are identified. AECL has developed several tools to manage the quantities of information required in aging assessment studies, such as the SYSTMS (SYtematic approach for the development of STrategy for Maintenance and Surveillance) tool and the System Maintenance Datastore (SMD). The SMD has been developed to serve as a hub to a Systematic based Adaptive Maintenance Program (SAMP), by storing maintenance resource requirements for recommended maintenance tasks for use by the other processes in a SAMP. The SMD can be used to (a) quantify the savings or cost of optimising a maintenance program, (b) characterize and understand long term trends in condition-based maintenance due to component aging, (c) quantify the resource savings due to optimum timing of component replacement or general plant refurbishment, and (d) provide aging assessment cost information for input to plant asset evaluation. The SMD contains data for regular maintenance program tasks, plant condition assessment recommendations, and equipment refurbishment costs. A prototype SMD has been developed with data tables populated with information from operating CANDU stations. The SMD is now available to be used either with a SYSTMS evaluation or with a plant's database of maintenance tasks. (author)

The development of memory maintenance: children's use of phonological rehearsal and attentional refreshment in working memory tasks.

Science.gov (United States)

Tam, Helen; Jarrold, Christopher; Baddeley, Alan D; Sabatos-DeVito, Maura

2010-11-01

Past research suggests that children begin to phonologically rehearse at around 7 years of age. Less is known regarding the development of refreshment, an attention-based maintenance mechanism. Therefore, the use of these two maintenance methods by 6- and 8-year-olds was assessed using memory span tasks that varied in their opportunities for maintenance activity. Experiment 1 showed that nonverbal processing impaired both groups' performance to similar extents. Experiment 2 employed phonologically similar or dissimilar memory items and compared the effects of verbal versus nonverbal processing on recall. Both groups showed evidence of phonological maintenance under nonverbal processing but not under verbal processing. Furthermore, nonverbal processing again impaired recall. Verbal processing was also more detrimental to performance in 8-year-olds than in 6-year-olds. Together, the results suggest that nonverbal processing impairs recall by obstructing refreshment and that developmental change in maintenance between 6 and 8 years of age consists primarily of an increase in phonological rehearsal. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Environmental hardening of robots for nuclear maintenance and surveillance tasks

International Nuclear Information System (INIS)

Hintenlang, D.E.; Tulenko, J.S.; Wheeler, R.; Roy, T.

1990-01-01

The University of Florida, in cooperation with the Universities of Texas, Tennessee, and Michigan and Oak Ridge National Laboratory, is developing an advanced robotic system for the US Department of Energy under the University Program for Robotics for Advanced Reactors. As part of this program, the University of Florida has been pursuing the development of environmentally hardened components so that autonomous robotic systems can successfully carry out their tasks under the most extreme expected environmental conditions. This requirement means that the designed robotic system with its onboard computer-based intelligence must be able to successfully complete tasks in toxic, radioactive, wet, temperature extremes, and other physically impairing environments. As part of this program, a study was carried out to determine the environmental conditions that should be set as the design criteria for robotic systems to maintain reasonable operations for nuclear plants in the course of maintenance, testing, and surveillance under all conditions, including plant upset. It was decided that Florida would build a combined environmental testing facility to test specific devices in high-radiation/high-temperature combined environments. This environmental test chamber has been built and successfully tested to over 250 degree F. This facility will provide some of the first combined temperatures/radiation data for many large-scale integrated components

Design Guidelines for the Development of Virtual Reality and Augmented Reality Training Systems for Maintenance and Assembly Tasks

Directory of Open Access Journals (Sweden)

Tecchia Franco

2011-12-01

Full Text Available The current work describes design guidelines for the development of Virtual Reality (VR and Augmented Reality (AR platforms to train technicians on maintenance and assembly tasks of industrial machineries. The main skill involved in this kind of tasks is the procedural skill. Based on past literature and studies conducted within the SKILLS project, several main design guidelines were formulated. First, observational learning integrated properly within the training protocol increases training efficiency. Second, training protocols combining physical and cognitive fidelity enhances procedural skills acquisition. Third, guidance aids should be provided in a proper and controlled way. And last, enriched information about the task helps trainees to develop a useful mental model of the task. These recommendations were implemented in both VR and AR training platforms.

Developmental changes in using verbal self-cueing in task-switching situations: the impact of task practice and task-sequencing demands

Science.gov (United States)

Kray, Jutta; Gaspard, Hanna; Karbach, Julia; Blaye, Agnès

2013-01-01

In this study we examined whether developmental changes in using verbal self-cueing for task-goal maintenance are dependent on the amount of task practice and task-sequencing demands. To measure task-goal maintenance we applied a switching paradigm in which children either performed only task A or B in single-task blocks or switched between them on every second trial in mixed-task blocks. Task-goal maintenance was determined by comparing the performance between both blocks (mixing costs). The influence of verbal self-cueing was measured by instructing children to either name the next task aloud or not to verbalize during task preparation. Task-sequencing demands were varied between groups whereas one group received spatial task cues to support keeping track of the task sequence, while the other group did not. We also varied by the amount of prior practice in task switching while one group of participants practiced task switching first, before performing the task naming in addition, and the other group did it vice versa. Results of our study investigating younger (8–10 years) and older children (11–13 years) revealed no age differences in beneficial effects of verbal self-cueing. In line with previous findings, children showed reduced mixing costs under task-naming instructions and under conditions of low task-sequence demands (with the presence of spatial task cues). Our results also indicated that these benefits were only obtained for those groups of children that first received practice in task switching alone with no additional verbalization instruction. These findings suggest that internal task-cueing strategies can be efficiently used in children but only if they received prior practice in the underlying task so that demands on keeping and coordinating various instructions are reduced. Moreover, children benefitted from spatial task cues for better task-goal maintenance only if no verbal task-cueing strategy was introduced first. PMID:24381566

Maintenance proficiency evaluation test bank

International Nuclear Information System (INIS)

Maier, Loran

2003-01-01

The Maintenance Proficiency Evaluation Test Bank (MPETB) is an Electric Power Research Institute- (EPRJ-) operated, utility-sponsored means of developing, maintaining, and disseminating secure, high-quality written and performance maintenance proficiency tests. EPRTs charter is to ensure that all tests and test items that go into the Test Bank have been validated, screened for reliability, and evaluated to high standards of psychometric excellence. Proficiency tests of maintenance personnel.(mechanics, electricians, and instrumentation and control [I and C] technicians) are most often used to determine if an experienced employee is capable of performing maintenance tasks without further training. Such tests provide objective evidence for decisions to exempt an employee from what, for the employee, is unnecessary training. This leads to considerable savings in training costs and increased productivity because supervisors can assign personnel to tasks at which their competence is proven. The ultimate objective of proficiency evaluation is to ensure that qualified maintenance personnel are available to meet the maintenance requirements of the plant Numerous task-specific MPE tests (both written and performance) have been developed and validated using the EPRI MPE methodology by the utilities participating in the MPETB project A task-specific MPE consists of a multiple-choice written examination and a multi-step performance evaluation that can be used to assess an individual's present knowledge and skill level for a given maintenance task. The MPETB contains MPEs and test items for the mechanical, electrical, and I and C classifications that are readily available to participating utilities. Presently, utilities are placing emphasis on developing MPEs to evaluate outage-related maintenance tasks that demonstrate the competency and qualifications of plant and contractor personnel before the start of outage work. Utilities are also using the MPE methodology and process to

Asbestos exposure of building maintenance personnel.

Science.gov (United States)

Mlynarek, S; Corn, M; Blake, C

1996-06-01

The exposures of building maintenance personnel and occupants to airborne asbestos fibers, and the effects of operations and maintenance programs on those exposures, continue to be an important public health issue. The subject of this investigation was a large metropolitan county with numerous public buildings which routinely conducted air sampling for asbestos. A total of 302 personal air samples in nine task categories collected during maintenance worker activities in proximity to asbestos-containing materials were analyzed; 102 environmental air samples in four task categories were also analyzed. The arithmetic means of the 8-hr time weighted average exposures for personal sampling for each task category were all below the Occupational Safety and Health Administration permissible exposure level of 0.1 fibers (f)/cc > 5 microm. The highest mean 8-hr time weighted average exposure was 0.030 f/cc > 5 microm for ceiling tile replacement. The maximum asbestos concentration during sample collection for environmental samples was 0.027 f/cc > 5 microm. All asbestos-related maintenance work was done within the framework of an Operations and Maintenance Program (OMP) which utilized both personal protective equipment and controls against fiber release/dispersion. Results are presented in association with specific OMP procedures or controls. These results support the effectiveness of using Operations and Maintenance Programs to manage asbestos in buildings without incurring unacceptable risk to maintenance workers performing maintenance tasks.

Job analysis of maintenance-mechanic position for the nuclear power plant maintenance personnel reliability model

International Nuclear Information System (INIS)

Siegel, A.I.; Bartter, W.D.; Kopstein, F.F.

1982-06-01

The task list method of job survey was used. In collaboration with BWR and PWR personnel, a list of 107 tasks performed by maintenance mechanics was developed, grouped into: remove and install, test and repair, inspect and perform preventive maintenance, miscellaneous, communication, and report preparation. For each listed task, the questionnaire form inquired into: frequency of performance, task completion time, safety consequences of improper performance, and the amount of training required to perform the task proficiently. Scaled information was requested about seven abilities: (1) visual speed, accuracy, and recognition; (2) gross motor coordination; (3) fine manual dexterity; (4) strength and stamina; (5) cognition; (6) memory; and (7) problem solving required for function completion. Survey forms were distributed to 27 nuclear power plants. Thirty-one maintenance mechanics representing 17 plants returned the completed forms. Frequency of performing tasks was bimodally distributed: (1) between once a year and once every six months, and (2) about once a week. More than half of the tasks have potential risk consequences if improperly performed. The five tasks with the greatest risk implications in the case of inadequate performance were: (1) remove and install reactor and dry-well heads, (2) test and repair reactor system components, (3) remove and install pressurizer mechanical relief valves, (4) test and repair pressurizer relief valves, (5) remove and install core spray pumps, seals, and valves. Hierarchically, the public risk associated with the various functions was: (1) remove and install, (2) test and repair, (3) preventive maintenance, (4) miscellaneous tasks, (5) communication, and (6) report preparation

Augmented reality application utility for aviation maintenance work instruction

Science.gov (United States)

Pourcho, John Bryan

Current aviation maintenance work instructions do not display information effectively enough to prevent costly errors and safety concerns. Aircraft are complex assemblies of highly interrelated components that confound troubleshooting and can make the maintenance procedure difficult (Drury & Gramopadhye, 2001). The sophisticated nature of aircraft maintenance necessitates a revolutionized training intervention for aviation maintenance technicians (United States General Accounting Office, 2003). Quite simply, the paper based job task cards fall short of offering rapid access to technical data and the system or component visualization necessary for working on complex integrated aircraft systems. Possible solutions to this problem include upgraded standards for paper based task cards and the use of integrated 3D product definition used on various mobile platforms (Ropp, Thomas, Lee, Broyles, Lewin, Andreychek, & Nicol, 2013). Previous studies have shown that incorporation of 3D graphics in work instructions allow the user to more efficiently and accurately interpret maintenance information (Jackson & Batstone, 2008). For aircraft maintenance workers, the use of mobile 3D model-based task cards could make current paper task card standards obsolete with their ability to deliver relevant, synchronized information to and from the hangar. Unlike previous versions of 3D model-based definition task cards and paper task cards, which are currently used in the maintenance industry, 3D model based definition task cards have the potential to be more mobile and accessible. Utilizing augmented reality applications on mobile devices to seamlessly deliver 3D product definition on mobile devices could increase the efficiency, accuracy, and reduce the mental workload for technicians when performing maintenance tasks (Macchiarella, 2004). This proposal will serve as a literary review of the aviation maintenance industry, the spatial ability of maintenance technicians, and benefits of

Maintenance-Ready Web Application Development

Directory of Open Access Journals (Sweden)

Ion IVAN

2016-01-01

Full Text Available The current paper tackles the subject of developing maintenance-ready web applications. Maintenance is presented as a core stage in a web application’s lifecycle. The concept of maintenance-ready is defined in the context of web application development. Web application maintenance tasks types are enunciated and suitable task types are identified for further analysis. The research hypothesis is formulated based on a direct link between tackling maintenance in the development stage and reducing overall maintenance costs. A live maintenance-ready web application is presented and maintenance related aspects are highlighted. The web application’s features, that render it maintenance-ready, are emphasize. The cost of designing and building the web-application to be maintenance-ready are disclosed. The savings in maintenance development effort facilitated by maintenance ready features are also disclosed. Maintenance data is collected from 40 projects implemented by a web development company. Homogeneity and diversity of collected data is evaluated. A data sample is presented and the size and comprehensive nature of the entire dataset is depicted. Research hypothesis are validated and conclusions are formulated on the topic of developing maintenance-ready web applications. The limits of the research process which represented the basis for the current paper are enunciated. Future research topics are submitted for debate.

The Effects of Task Demand and External Stimuli on Learner's Stress Perception and Performance

OpenAIRE

Lim, Yee Mei; Ayesh, Aladdin, 1972-; Stacey, Martin; Tan, Li Peng

2016-01-01

Over the past decades, research in e-learning has begun to take emotions into account, which is also known as affective learning. It advocates an education system that is sentient of learner's cognitive and affective states, as learners' performance could be affected by emotional factors. This exploratory research examines the impacts of task demand and external stimuli on learner's stress perception and job performance. Experiments are conducted on 160 undergraduate students from a higher le...

Nuclear maintenance strategy and first steps for preliminary maintenance plan of the EU HCLL & HCPB Test Blanket Systems

Energy Technology Data Exchange (ETDEWEB)

Galabert, Jose, E-mail: jose.galabert@f4e.europa.eu [F4E Fusion for Energy, EU Domestic Agency, c/Josep Pla, 2. B3, 08019, Barcelona (Spain); Hopper, Dave [AMEC Foster Wheeler, Faraday Street, Birchwood Park, WA3 6GN (United Kingdom); Neviere, Jean-Cristophe [ITER Organization, Route de Vinon-sur-Verdon, CS 90046, 13067, St. Paul Lez Durance Cedex (France); Nodwell, David [CCFE, Culham Science Centre, Abingdon, OX14 3DB, Oxfordshire (United Kingdom); Pascal, Romain [ITER Organization, Route de Vinon-sur-Verdon, CS 90046, 13067, St. Paul Lez Durance Cedex (France); Poitevin, Yves; Ricapito, Italo [F4E Fusion for Energy, EU Domestic Agency, c/Josep Pla, 2. B3, 08019, Barcelona (Spain); White, Gareth [AMEC Foster Wheeler, Faraday Street, Birchwood Park, WA3 6GN (United Kingdom)

2017-03-15

Highlights: • Nuclear maintenance strategy for the two European (EU) Test Blanket Systems (TBS): i/. Helium Cooled Lead Lithium (HCLL) and ii/. Helium Cooled Pebble Bed (HCPB). • Preliminary identification of maintenance tasks for most relevant components of the EU HCLL & HCPB TBS. • Preliminary feasibility analysis for hands-on maintenance tasks of some relevant components of the European Test Blanket Systems. • Design recommendations for enhancement of the European Test Blanket Systems maintainability. - Abstract: This paper gives an overview of nuclear maintenance strategy to be followed for the European HCLL & HCPB Test Blanket Systems (TBS) to be installed in ITER. One of the several core documents to prepare in view of their licensing is their respective ‘Maintenance Plan’. This document is fundamental for ensuring sound performance and safety of the TBS during ITER’s operational phase and shall include, amongst others, relevant information on: maintenance organization, preventive and corrective maintenance task procedures, condition monitoring for key components, maintenance work planning, and a spare parts plan, just to mention some of the key topics. In compliance with the ITER Plant Maintenance policy, first steps have been taken aimed at defining nuclear maintenance strategy for some of the most relevant HCLL & HCPB TBS components, conducted by F4E in collaboration with industry. After a brief recall of maintenance strategy of the TBM Program (PBS-56), this paper analyses main features of EU HCLL & HCPB TBS maintainability and identifies, at their conceptual design phase, a preliminary list of maintenance tasks to be developed for their most representative components. In addition, the paper also presents the first nuclear maintenance studies conducted for replacement of the Q{sub 2} Getter Beds, identifying some design recommendations for their sound maintainability.

Nuclear maintenance strategy and first steps for preliminary maintenance plan of the EU HCLL & HCPB Test Blanket Systems

International Nuclear Information System (INIS)

Galabert, Jose; Hopper, Dave; Neviere, Jean-Cristophe; Nodwell, David; Pascal, Romain; Poitevin, Yves; Ricapito, Italo; White, Gareth

2017-01-01

Highlights: • Nuclear maintenance strategy for the two European (EU) Test Blanket Systems (TBS): i/. Helium Cooled Lead Lithium (HCLL) and ii/. Helium Cooled Pebble Bed (HCPB). • Preliminary identification of maintenance tasks for most relevant components of the EU HCLL & HCPB TBS. • Preliminary feasibility analysis for hands-on maintenance tasks of some relevant components of the European Test Blanket Systems. • Design recommendations for enhancement of the European Test Blanket Systems maintainability. - Abstract: This paper gives an overview of nuclear maintenance strategy to be followed for the European HCLL & HCPB Test Blanket Systems (TBS) to be installed in ITER. One of the several core documents to prepare in view of their licensing is their respective ‘Maintenance Plan’. This document is fundamental for ensuring sound performance and safety of the TBS during ITER’s operational phase and shall include, amongst others, relevant information on: maintenance organization, preventive and corrective maintenance task procedures, condition monitoring for key components, maintenance work planning, and a spare parts plan, just to mention some of the key topics. In compliance with the ITER Plant Maintenance policy, first steps have been taken aimed at defining nuclear maintenance strategy for some of the most relevant HCLL & HCPB TBS components, conducted by F4E in collaboration with industry. After a brief recall of maintenance strategy of the TBM Program (PBS-56), this paper analyses main features of EU HCLL & HCPB TBS maintainability and identifies, at their conceptual design phase, a preliminary list of maintenance tasks to be developed for their most representative components. In addition, the paper also presents the first nuclear maintenance studies conducted for replacement of the Q_2 Getter Beds, identifying some design recommendations for their sound maintainability.

Externalizing psychopathology and gain-loss feedback in a simulated gambling task: dissociable components of brain response revealed by time-frequency analysis.

Science.gov (United States)

Bernat, Edward M; Nelson, Lindsay D; Steele, Vaughn R; Gehring, William J; Patrick, Christopher J

2011-05-01

Externalizing is a broad construct that reflects propensity toward a variety of impulse control problems, including antisocial personality disorder and substance use disorders. Two event-related potential responses known to be reduced among individuals high in externalizing proneness are the P300, which reflects postperceptual processing of a stimulus, and the error-related negativity (ERN), which indexes performance monitoring based on endogenous representations. In the current study, the authors used a simulated gambling task to examine the relation between externalizing proneness and the feedback-related negativity (FRN), a brain response that indexes performance monitoring related to exogenous cues, which is thought to be highly related to the ERN. Time-frequency (TF) analysis was used to disentangle the FRN from the accompanying P300 response to feedback cues by parsing the overall feedback-locked potential into distinctive theta (4-7 Hz) and delta (<3 Hz) TF components. Whereas delta-P300 amplitude was reduced among individuals high in externalizing proneness, theta-FRN response was unrelated to externalizing. These findings suggest that in contrast with previously reported deficits in endogenously based performance monitoring (as indexed by the ERN), individuals prone to externalizing problems show intact monitoring of exogenous cues (as indexed by the FRN). The results also contribute to a growing body of evidence indicating that the P300 is attenuated across a broad range of task conditions in high-externalizing individuals.

Preventive maintenance basis: Volume 31 -- Relays -- timing. Final report

International Nuclear Information System (INIS)

Worledge, D.; Hinchcliffe, G.

1998-07-01

US nuclear power plants are implementing preventive maintenance (PM) tasks with little documented basis beyond fundamental vendor information to support the tasks or their intervals. The Preventive Maintenance Basis project provides utilities with the technical basis for PM tasks and task intervals associated with 40 specific components such as valves, electric motors, pumps, and HVAC equipment. This document provides a program of preventive maintenance tasks suitable for application to timing relays. The PM tasks that are recommended provide a cost-effective way to intercept the causes and mechanisms that lead to degradation and failure. They can be used in conjunction with material from other sources, to develop a complete PM program or to improve an existing program

Preventive maintenance basis: Volume 30 -- Relays -- control. Final report

International Nuclear Information System (INIS)

Worledge, D.; Hinchcliffe, G.

1998-07-01

US nuclear power plants are implementing preventive maintenance (PM) tasks with little documented basis beyond fundamental vendor information to support the tasks or their intervals. The Preventive Maintenance Basis project provides utilities with the technical basis for PM tasks and task intervals associated with 40 specific components such as valves, electric motors, pumps, and HVAC equipment. This document provides a program of preventive maintenance tasks suitable for application to control relays. The PM tasks that are recommended provide a cost-effective way to intercept the causes and mechanisms that lead to degradation and failure. They can be used in conjunction with material from other sources, to develop a complete PM program or to improve an existing program

The effect of the nonhuman external regulator’s answer-until-correct (AUC) versus knowledge-of-result (KR) task feedback on children’s behavioral regulation during learning tasks

NARCIS (Netherlands)

Agina, Adel Masaud; Agina, Adel M.; Kommers, Petrus A.M.; Steehouder, M.F.

2011-01-01

The present study was conducted to shed a new light on the nonhuman’s external regulation effect on children’s behavioral regulation through investigating the effect of the computer’s task feedback answer-until-correct (AUC) versus knowledge-of-result (KR) with 40 preschool children (boys/girls)

After reliability centred maintenance. Preventive maintenance living program implementation at Bruce Power

International Nuclear Information System (INIS)

Harazim, Michael L.; Ferguson, Brian J.

2003-01-01

Industrial preventive maintenance (PM) programs represent a large part of plant O and M costs. PM Optimization (PMO) projects represent an effective mechanism for identifying unnecessary PM, extending PM intervals and infusing predictive maintenance (PdM) methods. However, once optimized, what process prevents the PM program from returning to a state of disarray? This is the function of a PM living program (PMLP). In 1997, an independent performance assessment identified concerns with the applicability and effectiveness of all Ontario Power Generation, Inc. (OPGI) PM programs. In response, OPGI instituted an Integrated Maintenance Program (IMP) including Reliability Centred Maintenance (RCM) and a PMLP. It should be noted that the PMLP was developed for the 3 OPGI nuclear Sites (i.e. Bruce, Pickering, and Darlington). Effective 1 May 2001, the Bruce Site has been leased to a group of investors lead by British Energy. This paper is written in historical context and therefore refers to the Bruce Site as part of OPGI. The PMLP is made up of five elements: 1) process control, 2) change control, 3) worker feedback, 4) program performance metrics, and 5) deferral module. A PMLP software tool, originally applied to Duke Energy nuclear plants, was enhanced and customized specifically for the OPGI PMLP, and then implemented at all three of OPGI's nuclear sites. The objective of the OPGI PMLP was to: Provide processes/procedures for continual optimization of all site PM tasks, Ensure effective and timely revision of PM tasks in the work management system, Ensure PM tasks remain applicable/effective at all times, Maintain and enhance PM consistency on a component, system and Site basis, Ensure that new predictive maintenance techniques are applied and integrated with the PM program, Ensure that mandated PM tasks are identified and executed, Provide a mechanism for craft feedback, Meet regulatory requirements for PM program effectiveness, and Provide PM task deferral

Maintenance training centre at NPP Paks, Hungary

International Nuclear Information System (INIS)

Babos, K.

1996-01-01

The lecture shows the feature of WWER-440/213 units maintenance, the existing maintenance training system, the necessity of the change in maintenance training system at NPP Paks. The author introduces the would-be maintenance training centre, the training facilities and the main tasks related to the maintenance training. (author)

Characteristics of organizational culture at the maintenance units of two Nordic nuclear power plants

International Nuclear Information System (INIS)

Reiman, Teemu; Oedewald, Pia; Rollenhagen, Carl

2005-01-01

This study aims to characterize and assess the organizational cultures of two Nordic nuclear power plant (NPP) maintenance units. The research consisted of NPP maintenance units of Forsmark (Sweden) and Olkiluoto (Finland). The study strives to anticipate the consequences of the current practices, conceptions and assumptions in the given organizations to their ability and willingness to fulfill the organizational core task. The methods utilized in the study were organizational culture and core task questionnaire (CULTURE02) and semi-structured interviews. Similarities and differences in the perceived organizational values, conceptions of one's own work, conceptions of the demands of the maintenance task and organizational practices at the maintenance units were explored. The maintenance units at Olkiluoto and Forsmark had quite different organizational cultures, but they also shared a set of dimensions such as strong personal emphasis placed on safety. The authors propose that different cultural features and organizational practices may be equally effective from the perspective of the core task. The results show that due to the complexity of the maintenance work, the case organizations tend to emphasize some aspects of the maintenance task more than others. The reliability consequences of these cultural solutions to the maintenance task are discussed. The authors propose that the organizational core task, in this case the maintenance task, should be clear for all the workers. The results give implications that this has been a challenge recently as the maintenance work has been changing. The concepts of organizational core task and organizational culture could be useful as management tools to anticipate the consequences of organizational changes

Industrial Maintenance Strategies

International Nuclear Information System (INIS)

Sajjad Akbar

2006-01-01

Industrial plants have become more complex due to technological advancement. This has made the task of maintenance more difficult. The maintenance costs in terms of resources and downtime loss are so high that maintenance function has become a critical factor in a plant's profitability. Industry should devote as much forethought to the management of maintenance function as to production. Maintenance has grown from an art to a precise, technical engineering science. Planning, organizing scheduling and control of maintenance using modern techniques pays dividends in the form of reduced costs and increased reliability. The magnitude and the dimension of maintenance have multiplied due to development in the engineering technologies. Production cost and capacities are directly affected by the breakdown time. Total operating cost including the maintenance cost plays an important role in replacement dimension. The integrated system approach would bring forth the desired results of high maintenance standards. The standards once achieved and sustained, would add to the reliability of the plan and relieve heavy stresses and strains on the engineering logistic support. (author)

Maintenance as a corporate strategy.

Science.gov (United States)

Clarke, D

2000-11-01

As we move towards the 21st century, those Manufacturing Industries that survive, will have changed their "efficiency" focus away from the conventional wisdom of "efficient individual tasks", to focus on the "effectiveness of a total manufacturing process". This seemingly insignificant change of emphasis, (from task to process) must include "the integration of process plant maintenance into the production process". Manufacturing companies, which do not include an effective plant maintenance strategy into their business strategy, will not survive the business environment of the 21st Century.

Status of fusion maintenance

International Nuclear Information System (INIS)

Fuller, G.M.

1984-01-01

Effective maintenance will be an essential ingredient in determining fusion system productivity. This level of productivity will result only after close attention is paid to the entire system as an entity and appropriate integration of the elements is made. The status of fusion maintenance is reviewed in the context of the entire system. While there are many challenging developmental tasks ahead in fusion maintenance, the required technologies are available in several high-technology industries, including nuclear fission

The Maintenance Personnel Performance Simulation (MAPPS) model: A human reliability analysis tool

International Nuclear Information System (INIS)

Knee, H.E.

1985-01-01

The Maintenance Personnel Performance Simulation (MAPPS) model is a computerized, stochastic, task-oriented human behavioral model developed to provide estimates of nuclear power plant (NPP) maintenance team performance measures. It is capable of addressing person-machine, person-environment, and person-person relationships, and accounts for interdependencies that exist between the subelements that make up the maintenance task of interest. The primary measures of performance estimated by MAPPS are: 1) the probability of successfully completing the task of interest and 2) the task duration time. MAPPS also estimates a host of other performance indices, including the probability of an undetected error, identification of the most- and least-likely error-prone subelements, and maintenance team stress profiles during task execution

Working memory updating occurs independently of the need to maintain task-context: accounting for triggering updating in the AX-CPT paradigm.

Science.gov (United States)

Kessler, Yoav; Baruchin, Liad J; Bouhsira-Sabag, Anat

2017-01-01

Theoretical models suggest that maintenance and updating are two functional states of working memory (WM), which are controlled by a gate between perceptual information and WM representations. Opening the gate enables updating WM with input, while closing it enables keeping the maintained information shielded from interference. However, it is still unclear when gate opening takes place, and what is the external signal that triggers it. A version of the AX-CPT paradigm was used to examine a recent proposal in the literature, suggesting that updating is triggered whenever the maintenance of the context is necessary for task performance (context-dependent tasks). In four experiments using this paradigm, we show that (1) a task-switching cost takes place in both context-dependent and context-independent trials; (2) task-switching is additive to the dependency effect, and (3) unlike switching cost, the dependency effect is not affected by preparation and, therefore, does not reflect context-updating. We suggest that WM updating is likely to be triggered by a simple mechanism that occurs in each trial of the task regardless of whether maintaining the context is needed or not. The implications for WM updating and its relationship to task-switching are discussed.

Investigating the Development of the Internal and External Service Tasks of Non-executive Directors: The Case of the Netherlands (1997-2005)

OpenAIRE

Bezemer, P.J.; Maassen, G.F.; van den Bosch, F.A.J.; Volberda, H.W.

2007-01-01

textabstractDuring the last decade, globalization and liberalization of financial markets, changing societal expectations and corporate governance scandals have increased the attention for the fiduciary duties of non-executive directors. In this context, recent corporate governance reform initiatives have emphasized the control task and independence of non-executive directors. However, little attention has been paid to their impact on the external and internal service tasks of non-executive d...

A human factors approach to effective maintenance

International Nuclear Information System (INIS)

Penington, J.; Shakeri, S.

2006-01-01

Traditionally in the field of Human Factors within the nuclear industry, the focus has been to identify the potential for human errors in operating tasks, and develop strategies to prevent their occurrence, provide recovery mechanisms, and mitigate the consequences of error as appropriate. Past experience has demonstrated however a significant number of human errors within the nuclear industry occur during maintenance tasks. It is for this reason, and the fact that our nuclear power plants are ageing and increasingly in need of maintenance, that the industry must pay more attention to maintenance tasks. The purpose of this paper is to present a framework for effective maintenance programs, and based upon this framework discuss an approach (an audit tool) that can be used to both design such a program, and to assess existing programs. In addition, this tool can form the basis of cost benefit decisions relating to priorities for improvements to existing programs. (author)

Preventive maintenance basis: Volume 19 -- HVAC -- chillers and compressors. Final report

International Nuclear Information System (INIS)

Worledge, D.; Hinchcliffe, G.

1997-12-01

US nuclear power plants are implementing preventive maintenance (PM) tasks with little documented basis beyond fundamental vendor information to support the tasks or their intervals. The Preventive Maintenance Basis project provides utilities with the technical basis for PM tasks and task intervals associated with 40 specific components such as valves, electric motors, pumps, and HVAC equipment. This document provides a program of preventive maintenance tasks suitable for application to HVAC -- Chillers and Compressors. The PM tasks that are recommended provide a cost-effective way to intercept the causes and mechanisms that lead to degradation and failure. They can be used in conjunction with material from other sources, to develop a complete PM program or to improve an existing program

External costs related to power production technologies. ExternE national implementation for Denmark

Energy Technology Data Exchange (ETDEWEB)

Schleisner, L; Sieverts Nielsen, P [eds.

1997-12-01

The objective of the ExternE National Implementation project has been to establish a comprehensive and comparable set of data on externalities of power generation for all EU member states and Norway. The tasks include the application of the ExternE methodology to the most important fuel cycles for each country as well as to update the already existing results, to aggregate these site- and technology-specific results to more general figures. The current report covers the detailed information concerning the ExternE methodology. Importance is attached to the computer system used in the project and the assessment of air pollution effects on health, materials and ecological effects. Also the assessment of global warming damages are described. Finally the report covers the detailed information concerning the national implementation for Denmark for an offshore wind farm and a wind farm on land, a decentralised CHP plant based on natural gas and a decentralised CHP plant base on biogas. (au) EU-JOULE 3. 79 tabs., 11 ills., 201 refs.

External costs related to power production technologies. ExternE national implementation for Denmark

International Nuclear Information System (INIS)

Schleisner, L.; Sieverts Nielsen, P.

1997-12-01

The objective of the ExternE National Implementation project has been to establish a comprehensive and comparable set of data on externalities of power generation for all EU member states and Norway. The tasks include the application of the ExternE methodology to the most important fuel cycles for each country as well as to update the already existing results, to aggregate these site- and technology-specific results to more general figures. The current report covers the detailed information concerning the ExternE methodology. Importance is attached to the computer system used in the project and the assessment of air pollution effects on health, materials and ecological effects. Also the assessment of global warming damages are described. Finally the report covers the detailed information concerning the national implementation for Denmark for an offshore wind farm and a wind farm on land, a decentralised CHP plant based on natural gas and a decentralised CHP plant base on biogas. (au) EU-JOULE 3. 79 tabs., 11 ills., 201 refs

Outsourcing versus in-house maintenance of medical devices: a longitudinal, empirical study.

Science.gov (United States)

Miguel-Cruz, Antonio; Rios-Rincón, Adriana; Haugan, Gregory L

2014-03-01

To determine what factors have a significant influence on the performance of medical device maintenance outsourcing, and to determine how the performance of external governance structures differs depending on whether a hospital is private or public. This was a longitudinal study of 590 maintenance transactions at 20 hospitals in Bogotá, Colombia, involving 764 medical devices and 72 maintenance service providers. Maintenance performance data (i.e., turn-around time in hours; TAT) for the service providers (either in-house or outsourced) were primarily collected over a 20-month period, from December 2009-August 2011, by means of a monitoring procedure; then, a hazards model was run. The availability of specific repair parts, in-stock, in the city in which the medical devices were located, had a positive impact on the performance of both internal and external governance structures. Online service also had a positive impact on both, with a stronger positive impact on the performance of internal governance than on that of external governance. For transactions governed by external structures, better performance was seen in private hospitals than in public ones. In public health institutions, internal governance showed better performance than external governance. Both internal and external governance structures showed better performance in private healthcare institutions than in public ones. In public health institutions, internal governance shows better performance than external governance; this suggests that healthcare managers should reconsider the trend to eliminate in-house maintenance service staff in public healthcare institutions.

The virtual maintenance system: a computer-based support tool for robust design, product monitoring, fault diagnosis and maintenance planning

NARCIS (Netherlands)

van Houten, Frederikus J.A.M.; Kimura, F.

2000-01-01

Digital (geometric) product models can be used for maintainability analysis and maintenance planning. It is not feasible to build digital product models for maintenance purposes only, but if a digital product model is available, it may be used to support many maintenance-related engineering tasks.

Preventive maintenance basis: Volume 37 -- Main turbine EHC hydraulics. Final report

International Nuclear Information System (INIS)

Worledge, D.; Hinchcliffe, G.

1998-11-01

US nuclear power plants are implementing preventive maintenance (PM) tasks with little documented basis beyond fundamental vendor information to support the tasks or their intervals. The Preventive Maintenance Basis project provides utilities with the technical basis for PM tasks and task intervals associated with 40 specific components such as valves, electric motors, pumps, and HVAC equipment. This document provides a program of preventive maintenance tasks suitable for application to the main turbine EHC hydraulic fluid and associated components. The PM tasks that are recommended provide a cost-effective way to intercept the causes and mechanisms that lead to degradation and failure. They can be used in conjunction with material from other sources, to develop a complete PM program or to improve an existing program

Mapping of the Underlying Neural Mechanisms of Maintenance and Manipulation in Visuo-Spatial Working Memory Using An n-back Mental Rotation Task: A Functional Magnetic Resonance Imaging Study.

Science.gov (United States)

Lamp, Gemma; Alexander, Bonnie; Laycock, Robin; Crewther, David P; Crewther, Sheila G

2016-01-01

Mapping of the underlying neural mechanisms of visuo-spatial working memory (WM) has been shown to consistently elicit activity in right hemisphere dominant fronto-parietal networks. However to date, the bulk of neuroimaging literature has focused largely on the maintenance aspect of visuo-spatial WM, with a scarcity of research into the aspects of WM involving manipulation of information. Thus, this study aimed to compare maintenance-only with maintenance and manipulation of visuo-spatial stimuli (3D cube shapes) utilizing a 1-back task while functional magnetic resonance imaging (fMRI) scans were acquired. Sixteen healthy participants (9 women, M = 23.94 years, SD = 2.49) were required to perform the 1-back task with or without mentally rotating the shapes 90° on a vertical axis. When no rotation was required (maintenance-only condition), a right hemispheric lateralization was revealed across fronto-parietal areas. However, when the task involved maintaining and manipulating the same stimuli through 90° rotation, activation was primarily seen in the bilateral parietal lobe and left fusiform gyrus. The findings confirm that the well-established right lateralized fronto-parietal networks are likely to underlie simple maintenance of visuo-spatial stimuli. The results also suggest that the added demand of manipulation of information maintained online appears to require further neural recruitment of functionally related areas. In particular mental rotation of visuospatial stimuli required bilateral parietal areas, and the left fusiform gyrus potentially to maintain a categorical or object representation. It can be concluded that WM is a complex neural process involving the interaction of an increasingly large network.

Performing maintenance activities on-line a risk perspective

International Nuclear Information System (INIS)

Darling, S.S.; Mairs, T.P.

1993-01-01

The US nuclear power industry is attempting to deal with the issue of optimizing the performance of maintenance activities with the advent of the maintenance rule. The impact of any maintenance activity on the safe operation of a nuclear power facility can be quantified on the basis of risk. Therefore, it is incumbent upon the industry to accommodate the regulator and present a maintenance optimization program in terms that explicitly address the potential risk inherent in its concept and implementation. The motivation for utilities to perform maintenance while the plant is operating (i.e., on-line) is readily perceived to offer the following advantages: 1. greater system availability; 2. higher plant capacity factor; 3. more evenly distributed workload for the maintenance department; and 4. overall safer plant operation. However, risks inherent in undertaking maintenance activities during power operation could amount to the realization that reapportionment of these tasks is not cost-beneficial. Therefore, it is important that any utility considering implementing such a paradigm in maintenance philosophy establish a rigorous process to select, perform, and monitor maintenance tasks performed while operating

Lean Maintenance Applied to Improve Maintenance Efficiency in Thermoelectric Power Plants

Directory of Open Access Journals (Sweden)

Orlando Duran

2017-10-01

Full Text Available Thermoelectric power plants consist of a set of critical equipment that require high levels of availability and reliability. Due to this, maintenance of these physical assets is gaining momentum in industry. Maintenance is considered as an activity that contributes to improving the availability, efficiency and productivity of each piece of equipment. Several techniques have been used to achieve greater efficiencies in maintenance, among which we can find the lean maintenance philosophy. Despite the wide diffusion of lean maintenance, there is no structured method that supports the prescription of lean tools applied to the maintenance function. This paper presents the experience gathered in two lean maintenance projects in thermoelectric power plants. The application of lean techniques was based on using a previously developed multicriterial decision making process that uses the Fuzzy Analytic Hierarchy Process (AHP methodology to carry out a diagnosis and prescription tasks. That methodology allowed the prescription of the appropriated lean techniques to resolve the main deficiencies in maintenance function. The results of applying such lean tools show that important results can be obtained, making the maintenance function in thermoelectric power plants more efficient and lean.

Data management in maintenance outsourcing

International Nuclear Information System (INIS)

Murthy, D.N.P.; Karim, M.R.; Ahmadi, A.

2015-01-01

Most businesses view maintenance as tasks carried out by technicians and the data collected is mostly cost related. There is a growing trend towards outsourcing of maintenance and the data collection issues are not addressed properly in most maintenance service contracts. Effective maintenance management requires proper data management - data collection and analysis for decision-making. This requires a proper framework and when maintenance is outsourced it raises several issues and challenges. The paper develops a framework for data management when maintenance is outsourced and looks at a real case study that highlights the need for proper data management. - Highlights: • Framework for data management in maintenance outsourcing. • Black-box to grey-box approaches for modelling. • Improvements to maintenance decision-making. • Case study to illustrate the approaches and the shortcomings in data collection

Outsourcing versus in-house maintenance of medical devices: a longitudinal, empirical study

Directory of Open Access Journals (Sweden)

Antonio Miguel-Cruz

2014-03-01

Full Text Available OBJECTIVE: To determine what factors have a significant influence on the performance of medical device maintenance outsourcing, and to determine how the performance of external governance structures differs depending on whether a hospital is private or public. METHODS: This was a longitudinal study of 590 maintenance transactions at 20 hospitals in Bogotá, Colombia, involving 764 medical devices and 72 maintenance service providers. Maintenance performance data (i.e., turn-around time in hours; TAT for the service providers (either in-house or outsourced were primarily collected over a 20-month period, from December 2009-August 2011, by means of a monitoring procedure; then, a hazards model was run. RESULTS: The availability of specific repair parts, in-stock, in the city in which the medical devices were located, had a positive impact on the performance of both internal and external governance structures. Online service also had a positive impact on both, with a stronger positive impact on the performance of internal governance than on that of external governance. For transactions governed by external structures, better performance was seen in private hospitals than in public ones. In public health institutions, internal governance showed better performance than external governance. Both internal and external governance structures showed better performance in private healthcare institutions than in public ones. CONCLUSIONS: In public health institutions, internal governance shows better performance than external governance; this suggests that healthcare managers should reconsider the trend to eliminate in-house maintenance service staff in public healthcare institutions.

Contextual assessment of maintenance culture at Olkiluoto and Forsmark

Energy Technology Data Exchange (ETDEWEB)

Reiman, T.; Oedewald, P. [VTT Industrial Systems (Finland); Rollenhagen, C.; Eriksson, I. [Maelardalen University (Sweden)

2004-04-01

The study aims to characterise, assess and develop the organisational cultures of participating nuclear power companies' maintenance units. The assessment is made by the means of maintenance core task modelling that has already been started in previous studies. The theoretical core task model is used in evaluating the characteristics of the organisational culture. We aim to identify what are the strengths and weaknesses of the case organisation's culture in relation to its core task. The study also aims to validate the methodology for contextual assessment of organisational culture. In addition to case specific results, the study acts as a benchmark between the participating companies and gives a chance to compare the different culture profiles between the companies. Similarities and differences between the organisational cultures at the maintenance units were identified. The purpose is not however to evaluate which organisation is better, but to raise issues that require attention at the organisations. When evaluative statements are made, the criteria are formed on the basis of the core task model: Even though the practices differ, from the perspective of the maintenance core task they might both be as effective. (au)

Contextual assessment of maintenance culture at Olkiluoto and Forsmark

International Nuclear Information System (INIS)

Reiman, T.; Oedewald, P.; Rollenhagen, C.; Eriksson, I.

2004-04-01

The study aims to characterise, assess and develop the organisational cultures of participating nuclear power companies' maintenance units. The assessment is made by the means of maintenance core task modelling that has already been started in previous studies. The theoretical core task model is used in evaluating the characteristics of the organisational culture. We aim to identify what are the strengths and weaknesses of the case organisation's culture in relation to its core task. The study also aims to validate the methodology for contextual assessment of organisational culture. In addition to case specific results, the study acts as a benchmark between the participating companies and gives a chance to compare the different culture profiles between the companies. Similarities and differences between the organisational cultures at the maintenance units were identified. The purpose is not however to evaluate which organisation is better, but to raise issues that require attention at the organisations. When evaluative statements are made, the criteria are formed on the basis of the core task model: Even though the practices differ, from the perspective of the maintenance core task they might both be as effective. (au)

The working memory stroop effect: when internal representations clash with external stimuli.

Science.gov (United States)

Kiyonaga, Anastasia; Egner, Tobias

2014-08-01

Working memory (WM) has recently been described as internally directed attention, which implies that WM content should affect behavior exactly like an externally perceived and attended stimulus. We tested whether holding a color word in WM, rather than attending to it in the external environment, can produce interference in a color-discrimination task, which would mimic the classic Stroop effect. Over three experiments, the WM Stroop effect recapitulated core properties of the classic attentional Stroop effect, displaying equivalent congruency effects, additive contributions from stimulus- and response-level congruency, and susceptibility to modulation by the percentage of congruent and incongruent trials. Moreover, WM maintenance was inversely related to attentional demands during the WM delay between stimulus presentation and recall, with poorer memory performance following incongruent than congruent trials. Together, these results suggest that WM and attention rely on the same resources and operate over the same representations. © The Author(s) 2014.

Maintenance Personnel Performance Simulation (MAPPS) model: a human reliability analysis tool

International Nuclear Information System (INIS)

Knee, H.E.

1985-01-01

The Maintenance Personnel Performance Simulation (MAPPS) model is a computerized, stochastic, task-oriented human behavioral model developed to provide estimates of nuclear power plant (NPP) maintenance team performance measures. It is capable of addressing person-machine, person-environment, and person-person relationships, and accounts for interdependencies that exist between the subelements that make up the maintenance task of interest. The primary measures of performance estimated by MAPPS are: (1) the probability of successfully completing the task of interest; and (2) the task duration time. MAPPS also estimates a host of other performance indices, including the probability of an undetected error, identification of the most- and least-likely error-prone subelements, and maintenance team stress profiles during task execution. The MAPPS model was subjected to a number of evaluation efforts that focused upon its practicality, acceptability, usefulness, and validity. Methods used for these efforts included a case method approach, consensus estimation, and comparison with observed task performance measures at a NPP. Favorable results, such as close agreement between task duration times for two tasks observed in the field (67.0 and 119.8 minutes, respectively), and estimates by MAPPS (72.0 and 124.0 minutes, respectively) enhance the confidence in the future use of MAPPS. 8 refs., 1 fig

The default mode network and the working memory network are not anti-correlated during all phases of a working memory task.

Science.gov (United States)

Piccoli, Tommaso; Valente, Giancarlo; Linden, David E J; Re, Marta; Esposito, Fabrizio; Sack, Alexander T; Di Salle, Francesco

2015-01-01

The default mode network and the working memory network are known to be anti-correlated during sustained cognitive processing, in a load-dependent manner. We hypothesized that functional connectivity among nodes of the two networks could be dynamically modulated by task phases across time. To address the dynamic links between default mode network and the working memory network, we used a delayed visuo-spatial working memory paradigm, which allowed us to separate three different phases of working memory (encoding, maintenance, and retrieval), and analyzed the functional connectivity during each phase within and between the default mode network and the working memory network networks. We found that the two networks are anti-correlated only during the maintenance phase of working memory, i.e. when attention is focused on a memorized stimulus in the absence of external input. Conversely, during the encoding and retrieval phases, when the external stimulation is present, the default mode network is positively coupled with the working memory network, suggesting the existence of a dynamically switching of functional connectivity between "task-positive" and "task-negative" brain networks. Our results demonstrate that the well-established dichotomy of the human brain (anti-correlated networks during rest and balanced activation-deactivation during cognition) has a more nuanced organization than previously thought and engages in different patterns of correlation and anti-correlation during specific sub-phases of a cognitive task. This nuanced organization reinforces the hypothesis of a direct involvement of the default mode network in cognitive functions, as represented by a dynamic rather than static interaction with specific task-positive networks, such as the working memory network.

Reservoir Maintenance and Development Task Report for the DOE Geothermal Technologies Office GeoVision Study.

Energy Technology Data Exchange (ETDEWEB)

Lowry, Thomas Stephen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Finger, John T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Carrigan, Charles R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Foris, Adam [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kennedy, Mack B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Corbet, Thomas F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Doughty, Christine A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pye, Steven [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sonnenthal, Eric L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-09-01

This report documents the key findings from the Reservoir Maintenance and Development (RM&D) Task of the U.S. Department of Energy's (DOE), Geothermal Technologies Office (GTO) Geothermal Vision Study (GeoVision Study). The GeoVision Study had the objective of conducting analyses of future geothermal growth based on sets of current and future geothermal technology developments. The RM&D Task is one of seven tasks within the GeoVision Study with the others being, Exploration and Confirmation, Potential to Penetration, Institutional Market Barriers, Environmental and Social Impacts, Thermal Applications, and Hybrid Systems. The full set of findings and the details of the GeoVision Study can be found in the final GeoVision Study report on the DOE-GTO website. As applied here, RM&D refers to the activities associated with developing, exploiting, and maintaining a known geothermal resource. It assumes that the site has already been vetted and that the resource has been evaluated to be of sufficient quality to move towards full-scale development. It also assumes that the resource is to be developed for power generation, as opposed to low-temperature or direct use applications. This document presents the key factors influencing RM&D from both a technological and operational standpoint and provides a baseline of its current state. It also looks forward to describe areas of research and development that must be pursued if the development geothermal energy is to reach its full potential.

Airline experience with reliability-centered maintenance

International Nuclear Information System (INIS)

Matteson, T.D.

1985-01-01

Reliability-Centered Maintenance is a process for developing preventive maintenance programs. Its concepts evolved from the post WWII experience of the airline community. Its genesis was in a paper by F. Stanley Nowlan and Thomas D. Matteson of United Airlines for the American Institute of Aeronautics and Astronautics in 1967. Its first application was to the Boeing 747. It has subsequently been adopted by the FAA and the Department of Defense and applied to many new transport and military aircraft. Its objective is applicable and effective preventive maintenance and it has proven to be a highly effective replacement for the prior intuitive processes for selective preventive maintenance tasks. It focuses on system functions, functional failures, then dominant failure modes and effects. It then uses a decision tree to classify failure criticality and identify applicable and effective tasks. The result is a program focused on maintaining inherent safety and reliability at minimum cost. (orig.)

Airline experience with reliability-centered maintenance

Energy Technology Data Exchange (ETDEWEB)

Matteson, T.D.

1985-11-01

Reliability-Centered Maintenance is a process for developing preventive maintenance programs. Its concepts evolved from the post WWII experience of the airline community. Its genesis was in a paper by F. Stanley Nowlan and Thomas D. Matteson of United Airlines for the American Institute of Aeronautics and Astronautics in 1967. Its first application was to the Boeing 747. It has subsequently been adopted by the FAA and the Department of Defense and applied to many new transport and military aircraft. Its objective is applicable and effective preventive maintenance and it has proven to be a highly effective replacement for the prior intuitive processes for selective preventive maintenance tasks. It focuses on system functions, functional failures, then dominant failure modes and effects. It then uses a decision tree to classify failure criticality and identify applicable and effective tasks. The result is a program focused on maintaining inherent safety and reliability at minimum cost. (orig.).

External costs related to power production technologies. ExternE national implementation for Denmark

International Nuclear Information System (INIS)

Schleisner, L.; Sieverts Nielsen, P.

1997-12-01

The objective of the ExternE National Implementation project has been to establish a comprehensive and comparable set of data on externalities of power generation for all EU member states and Norway. The tasks include the application of the ExternE methodology to the most important fuel cycles for each country as well as to update the already existing results; to aggregate these site- and technology-specific results to more general figures. The current report covers the results of the national implementation for Denmark. Three different fuel cycles have been chosen as case studies. These are fuel cycles for an offshore wind farm and a wind farm on land, a decentralised CHP plant based on natural gas and a decentralised CHP plant based on biogas. The report covers all the details of the application of the methodology to these fuel cycles aggregation to a national level. (au) EU-JOULE 3. 59 tabs., 25 ills., 61 refs

External costs related to power production technologies. ExternE national implementation for Denmark

Energy Technology Data Exchange (ETDEWEB)

Schleisner, L; Sieverts Nielsen, P

1997-12-01

The objective of the ExternE National Implementation project has been to establish a comprehensive and comparable set of data on externalities of power generation for all EU member states and Norway. The tasks include the application of the ExternE methodology to the most important fuel cycles for each country as well as to update the already existing results; to aggregate these site- and technology-specific results to more general figures. The current report covers the results of the national implementation for Denmark. Three different fuel cycles have been chosen as case studies. These are fuel cycles for an offshore wind farm and a wind farm on land, a decentralised CHP plant based on natural gas and a decentralised CHP plant based on biogas. The report covers all the details of the application of the methodology to these fuel cycles aggregation to a national level. (au) EU-JOULE 3. 59 tabs., 25 ills., 61 refs.

A concept of distributed architecture for maintenance robot systems

International Nuclear Information System (INIS)

Asama, Hajime

1990-01-01

Aiming at development of a robot system for maintenance tasks in nuclear power plants, a concept of distributed architecture for autonomous robot systems is discussed. At first, based on investigation of maintenance tasks, requirements for maintenance robots are introduced, and structures to realize multi-functions are discussed. Then, as a new design strategy of maintenance robot system, an autonomous and decentralized robot systems is proposed, which is composed of multiple robots, computers, and equipments, and concept of ACTRESS (ACTor-based Robots and Equipments Synthetic System) including communication framework between robotic components is designed. Finally, as a model of ACTRESS, a experimental system is developed, which deals with object-pushing tasks by two micromice and an environment modeler with communicating with each other. Both of parallel independent motion and cooperative motion based on communication is reconciled, and the efficiency of the distributed architecture is verified. (author)

Caffeine improves anticipatory processes in task switching

NARCIS (Netherlands)

Tieges, Zoe; Snel, Jan; Kok, Albert; Wijnen, Jasper G.; Lorist, Monicque M.; Ridderinkhof, K. Richard

We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials

An exploration of the relations between external representations and working memory.

Directory of Open Access Journals (Sweden)

Jiajie Zhang

Full Text Available It is commonly hypothesized that external representations serve as memory aids and improve task performance by means of expanding the limited capacity of working memory. However, very few studies have directly examined this memory aid hypothesis. By systematically manipulating how information is available externally versus internally in a sequential number comparison task, three experiments were designed to investigate the relation between external representations and working memory. The experimental results show that when the task requires information from both external representations and working memory, it is the interaction of information from the two sources that determines task performance. In particular, when information from the two sources does not match well, external representations hinder instead of enhance task performance. The study highlights the important role the coordination among different representations plays in distributed cognition. The general relations between external representations and working memory are discussed.

Differential effects of white noise in cognitive and perceptual tasks

Directory of Open Access Journals (Sweden)

Nora Alicia Herweg

2015-11-01

Full Text Available Beneficial effects of noise on higher cognition have recently attracted attention. Hypothesizing an involvement of the mesolimbic dopamine system and its functional interactions with cortical areas, the current study aimed to demonstrate a facilitation of dopamine-dependent attentional and mnemonic functions by externally applying white noise in five behavioral experiments including a total sample of 167 healthy human subjects. During working memory, acoustic white noise impaired accuracy when presented during the maintenance period (experiment 1-3. In a reward based long-term memory task, white noise accelerated perceptual judgments for scene images during encoding but left subsequent recognition memory unaffected (experiment 4. In a modified Posner task (experiment 5, the benefit due to white noise in attentional orienting correlated weakly with reward dependence, a personality trait that has been associated with the dopaminergic system. These results suggest that white noise has no general effect on cognitive functions. Instead, they indicate differential effects on perception and cognition depending on a variety of factors such as task demands and timing of white noise presentation.

Differential effects of white noise in cognitive and perceptual tasks.

Science.gov (United States)

Herweg, Nora A; Bunzeck, Nico

2015-01-01

Beneficial effects of noise on higher cognition have recently attracted attention. Hypothesizing an involvement of the mesolimbic dopamine system and its functional interactions with cortical areas, the current study aimed to demonstrate a facilitation of dopamine-dependent attentional and mnemonic functions by externally applying white noise in five behavioral experiments including a total sample of 167 healthy human subjects. During working memory, acoustic white noise impaired accuracy when presented during the maintenance period (Experiments 1-3). In a reward based long-term memory task, white noise accelerated perceptual judgments for scene images during encoding but left subsequent recognition memory unaffected (Experiment 4). In a modified Posner task (Experiment 5), the benefit due to white noise in attentional orienting correlated weakly with reward dependence, a personality trait that has been associated with the dopaminergic system. These results suggest that white noise has no general effect on cognitive functions. Instead, they indicate differential effects on perception and cognition depending on a variety of factors such as task demands and timing of white noise presentation.

The future of artificial intelligence in nuclear plant maintenance

International Nuclear Information System (INIS)

Norgate, G.

1984-01-01

Robots with vision and force sensing capability, performing tasks under computer control, will offer new opportunities to reduce human exposure to radiation. Such machines do not yet exist and even simple maintenance tasks challenge current robot technology. Recently increased priority for research on artificial intelligence and fifth generation computer technology is likely to bring useful maintenance robots closer to reality

Transportation cask decontamination and maintenance at the potential Yucca Mountain repository

International Nuclear Information System (INIS)

Hartman, D.J.; Miller, D.D.; Hill, R.R.

1992-04-01

This study investigates spent fuel cask handling experience at existing nuclear facilities to determine appropriate cask decontamination and maintenance operations at the potential Yucca Mountain repository. These operations are categorized as either routine or nonroutine. Routine cask decontamination and maintenance tasks are performed in the cask preparation area at the repository. Casks are taken offline to a separate cask maintenance area for major nonroutine tasks. The study develops conceptual designs of the cask preparation area and cask maintenance area. The functions, layouts, and major features of these areas are also described

Annual report of the maintenance division for 1965

International Nuclear Information System (INIS)

Nikolic, M.

1965-12-01

The personnel of the Division is organized in groups, each responsible for a number of tasks related to maintenance of reactor mechanical structures, electric equipment, electronic equipment. According to the action plan for 1965 the division for RA reactor maintenance the main activities were: planned maintenance of the reactor components, planned repair of the main components, indispensable repairs during reactor operation, repair during planned shutdown periods and tasks related to improvement of operation components and systems. Quite a significant number of failures was related to electronic equipment resulting from failures of thermometers in the heavy water system due to vibrations of the pumps. A number of spare parts and tools were produced needed for maintenance of reactor components, as well as instruments for control and calibration of reactor measuring devices [sr

Exploring Virtual Mental Practice in Maintenance Task Training

Science.gov (United States)

Bauerle, Tim; Brnich, Michael J.; Navoyski, Jason

2016-01-01

Purpose: This paper aims to contribute to a general understanding of mental practice by investigating the utility of and participant reaction to a virtual reality maintenance training among underground coal mine first responders. Design/Methodology/Approach: Researchers at the National Institute for Occupational Safety and Health's Office of Mine…

Verifying elementary ITER maintenance actions with the MS2 benchmark product

NARCIS (Netherlands)

Heemskerk, C. J. M.; Elzendoorn, B. S. Q.; Magielsen, A. J.; Schropp, G. Y. R.

2011-01-01

A new facility has been taken in operation to investigate the influence of visual and haptic feedback on the performance of remotely executed ITER RH maintenance tasks. A reference set of representative ITER remote handling maintenance tasks was included the master slave manipulator system (MS2)

Pilot Study for Maintenance Rule at KSNP

International Nuclear Information System (INIS)

Choi, Kwang Hee; Jeong, Hyeon Jong; Jee, Moon Hak; Hong, Sung Yull

2005-01-01

Maintenance Rule (MR), which was developed to monitor the effectiveness of maintenance in a nuclear power plant (NPP), has been received as highly successful program by and large since its implementation in 1996 in the United States. Korea has initiated two pilot programs to implement the Maintenance Rule program in 2003. Selected plants for the pilot implementation are Kori 3 and 4 units and Ulchin 3 and 4 units, where Kori 3 and 4 units are Westinghouse units and Ulchin 3 and 4 units are Korean Standardized Nuclear Power (KSNP) Plant units. This paper describes the results of each key tasks completed to date and insights gained from pilot study on the KSNP units. Currently, Scoping of the functions of maintenance rule and determination of safety significance level have been completed during first year. As first task, total 607 functions were identified and defined by detailed function analysis on 135 systems that cover all plant systems. About 55% of total functions are selected as within the scope of maintenance rule. Among these inscoped functions, 56% of scoped functions are safety related and 44% are non-safety related functions. Evaluation of safety significance for each function was determined by expert panel consist of eight experts in field of plant maintenance, operation, PSA, work schedule and system engineers. As a result, about 46% of functions were determined to be high safety significant functions and rest of the functions were classified as low safety significant. The remaining tasks that are included determination of performance criteria and preparation of implementing guideline will be performed in following years

Heimdall System for MSSS Sensor Tasking

Science.gov (United States)

Herz, A.; Jones, B.; Herz, E.; George, D.; Axelrad, P.; Gehly, S.

In Norse Mythology, Heimdall uses his foreknowledge and keen eyesight to keep watch for disaster from his home near the Rainbow Bridge. Orbit Logic and the Colorado Center for Astrodynamics Research (CCAR) at the University of Colorado (CU) have developed the Heimdall System to schedule observations of known and uncharacterized objects and search for new objects from the Maui Space Surveillance Site. Heimdall addresses the current need for automated and optimized SSA sensor tasking driven by factors associated with improved space object catalog maintenance. Orbit Logic and CU developed an initial baseline prototype SSA sensor tasking capability for select sensors at the Maui Space Surveillance Site (MSSS) using STK and STK Scheduler, and then added a new Track Prioritization Component for FiSST-inspired computations for predicted Information Gain and Probability of Detection, and a new SSA-specific Figure-of-Merit (FOM) for optimized SSA sensor tasking. While the baseline prototype addresses automation and some of the multi-sensor tasking optimization, the SSA-improved prototype addresses all of the key elements required for improved tasking leading to enhanced object catalog maintenance. The Heimdall proof-of-concept was demonstrated for MSSS SSA sensor tasking for a 24 hour period to attempt observations of all operational satellites in the unclassified NORAD catalog, observe a small set of high priority GEO targets every 30 minutes, make a sky survey of the GEO belt region accessible to MSSS sensors, and observe particular GEO regions that have a high probability of finding new objects with any excess sensor time. This Heimdall prototype software paves the way for further R&D that will integrate this technology into the MSSS systems for operational scheduling, improve the software's scalability, and further tune and enhance schedule optimization. The Heimdall software for SSA sensor tasking provides greatly improved performance over manual tasking, improved

49 CFR 193.2629 - External corrosion control: buried or submerged components.

Science.gov (United States)

2010-10-01

...) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS Maintenance § 193.2629 External... external corrosive attack must be protected from external corrosion by— (1) Material that has been designed...

Decreasing inventory of a cement factory roller mill parts using reliability centered maintenance method

Science.gov (United States)

Witantyo; Rindiyah, Anita

2018-03-01

According to data from maintenance planning and control, it was obtained that highest inventory value is non-routine components. Maintenance components are components which procured based on maintenance activities. The problem happens because there is no synchronization between maintenance activities and the components required. Reliability Centered Maintenance method is used to overcome the problem by reevaluating maintenance activities required components. The case chosen is roller mill system because it has the highest unscheduled downtime record. Components required for each maintenance activities will be determined by its failure distribution, so the number of components needed could be predicted. Moreover, those components will be reclassified from routine component to be non-routine component, so the procurement could be carried out regularly. Based on the conducted analysis, failure happens in almost every maintenance task are classified to become scheduled on condition task, scheduled discard task, schedule restoration task and no schedule maintenance. From 87 used components for maintenance activities are evaluated and there 19 components that experience reclassification from non-routine components to routine components. Then the reliability and need of those components were calculated for one-year operation period. Based on this invention, it is suggested to change all of the components in overhaul activity to increase the reliability of roller mill system. Besides, the inventory system should follow maintenance schedule and the number of required components in maintenance activity so the value of procurement will be decreased and the reliability system will increase.

Phonological similarity effect in complex span task.

Science.gov (United States)

Camos, Valérie; Mora, Gérôme; Barrouillet, Pierre

2013-01-01

The aim of our study was to test the hypothesis that two systems are involved in verbal working memory; one is specifically dedicated to the maintenance of phonological representations through verbal rehearsal while the other would maintain multimodal representations through attentional refreshing. This theoretical framework predicts that phonologically related phenomena such as the phonological similarity effect (PSE) should occur when the domain-specific system is involved in maintenance, but should disappear when concurrent articulation hinders its use. Impeding maintenance in the domain-general system by a concurrent attentional demand should impair recall performance without affecting PSE. In three experiments, we manipulated the concurrent articulation and the attentional demand induced by the processing component of complex span tasks in which participants had to maintain lists of either similar or dissimilar words. Confirming our predictions, PSE affected recall performance in complex span tasks. Although both the attentional demand and the articulatory requirement of the concurrent task impaired recall, only the induction of an articulatory suppression during maintenance made the PSE disappear. These results suggest a duality in the systems devoted to verbal maintenance in the short term, constraining models of working memory.

Subcontracting Railway Maintenance

DEFF Research Database (Denmark)

Thommesen, Jacob

2010-01-01

railway infrastructure manager (InfraMan), whichis subcontracting maintenance tasks to other companies. InfraMan has implemented various central elements in managing their subcontractors. The latter are required to present a safety plan as part of their bid, they must be approved if they are to be awarded...

Automated pose estimation of objects using multiple ID devices for handling and maintenance task in nuclear fusion reactor

International Nuclear Information System (INIS)

Umetani, Tomohiro; Morioka, Jun-ichi; Tamura, Yuichi; Inoue, Kenji; Arai, Tatsuo; Mae, Yasusi

2011-01-01

This paper describes a method for the automated estimation of three-dimensional pose (position and orientation) of objects by autonomous robots, using multiple identification (ID) devices. Our goal is to estimate the object pose for assembly or maintenance tasks in a real nuclear fusion reactor system, with autonomous robots cooperating in a virtual assembly system. The method estimates the three-dimensional pose for autonomous robots. This paper discusses a method of motion generation for ID acquisition using the sensory data acquired by the measurement system attached to the robots and from the environment. Experimental results show the feasibility of the proposed method. (author)

Main maintenance operations for Test Blanket Systems in ITER TBM port cells

Energy Technology Data Exchange (ETDEWEB)

Pascal, R., E-mail: romain.pascal@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Cortes, P.; Friconneau, J.-P.; Giancarli, L.M.; Gotewal, K.K.; Iseli, M.; Kim, B.Y.; Levesy, B.; Martins, J.-P.; Merola, M. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Nevière, J.-C. [Comex-Nucleaire, 13115 Saint Paul Lez Durance (France); Patisson, L. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Siarras, A. [Sogetti, Parc de la Duranne, 13857 Aix-en-Provence (France); Tesini, A. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

2013-10-15

Highlights: • The Test Blanket System components layout in Port Cell room is described. • The maintenance of the two Test Blanket Systems in ITER port cell is addressed. • The overall replacement/maintenance strategy is defined. • The main maintenance tasks of the systems are discussed. • The maintenance strategy and required tools are presented. -- Abstract: Each Test Blanket System in ITER is formed by an in-vessel component, the Test Blanket Module, and several associated ancillary systems (coolant and Tritium systems, instrumentation and control systems). The paper describes the overall replacement/maintenance strategy and the main maintenance tasks that have to be considered in the design of the systems. It shows that there are no critical issues.

Verifying elementary ITER maintenance actions with the MS2 benchmark product

International Nuclear Information System (INIS)

Heemskerk, C.J.M.; Elzendoorn, B.S.Q.; Magielsen, A.J.; Schropp, G.Y.R.

2011-01-01

A new facility has been taken in operation to investigate the influence of visual and haptic feedback on the performance of remotely executed ITER RH maintenance tasks. A reference set of representative ITER remote handling maintenance tasks was included the master slave manipulator system (MS2) benchmark product. The benchmark product was used in task performance tests in a representative two-handed dexterous manipulation test bed at NRG. In the setup, the quality of visual feedback was varied by exchanging direct view with indirect view setups in which visual feedback is provided via video cameras. Interaction forces were measured via an integrated force sensor. The impact of feedback quality on the performance of maintenance tasks at the level of handling individual parts was measured and analysed. Remote execution of the maintenance actions took roughly 3-5 times more time than hands-on. Visual feedback was identified as the dominant factor, including aspects like (lack of) operator control over camera placement, pan, tilt and zoom, lack of 3D perception, image quality, and latency. Haptic feedback was found to be important, but only in specific contact transition and constrained motion tasks.

ATLAS Maintenance and Operation management system

CERN Document Server

Copy, B

2007-01-01

The maintenance and operation of the ATLAS detector will involve thousands of contributors from 170 physics institutes. Planning and coordinating the action of ATLAS members, ensuring their expertise is properly leveraged and that no parts of the detector are understaffed or overstaffed will be a challenging task. The ATLAS Maintenance and Operation application (referred to as Operation Task Planner inside the ATLAS experiment) offers a fluent web based interface that combines the flexibility and comfort of a desktop application, intuitive data visualization and navigation techniques, with a lightweight service oriented architecture. We will review the application, its usage within the ATLAS experiment, its underlying design and implementation.

Computerized management of plant intervention tasks

International Nuclear Information System (INIS)

Quoidbach, G.

2004-01-01

The main objective of the 'Computerized Management of Plant Intervention Tasks' is to help the staff of a nuclear or a conventional power plant or of any other complex industrial facility (chemical industries, refineries, and so on) in planning, organizing, and carrying out any (preventive or corrective) maintenance task. This 'Computerized Management of Plant Intervention Tasks' is organized around a data base of all plant components in the facility that might be subjected to maintenance or tagout. It allows to manage, by means of intelligent and configurable 'mail service', the course of the intervention requests as well as various treatments of those requests, in a safe and efficient way, adapted to each particular organization. The concept of 'Computerized Management' of plant intervention tasks was developed by BELGATOM in 1983 for the Belgian nuclear power plants of ELECTRABEL. A first implementation of this concept was made at that time for the Doel NPP under the name POPIT (Programming Of Plant Intervention Tasks). In 1988, it was decided to proceed to a functional upgrade of the application, using advanced software and hardware techniques and products, and to realize a second implementation in the Tihange NPP under the name ACM (Application Consignation Maintenance). (author)

The ITER EC H and CD Upper Launcher: Maintenance concepts

International Nuclear Information System (INIS)

Ronden, D.M.S.; Baar, M. de; Chavan, R.; Elzendoorn, B.S.Q.; Grossetti, G.; Heemskerk, C.J.M.; Koning, J.F.; Landis, J.-D.; Spaeh, P.; Strauss, D.

2013-01-01

Highlights: ► We explain how an overall maintenance strategy defines individual maintenance tasks. ► Concepts are presented for replacement strategies of the in-vessel optical components. ► Vertical placement of the Upper Launcher in the Hot Cell may simplify maintenance. -- Abstract: Maintenance of the ITER EC H and CD Upper Launcher (UL) shall be performed through the use of Remote Handling (RH) in the ITER Hot Cell Facility (HCF). The UL design will have to be fully compliant with ITER RH maintenance requirements and the set of RH tooling and services available in the HCF. This paper describes the development of an overall maintenance strategy for the UL, starting from a listing of all conceivable maintenance operations, including hands-on tasks. Components for which design concepts are discussed in this paper are the Blanket Shield Module (BSM), the steering mirror (M4), the mid optics (M1, M2) and the waveguide (WG) feed-through plate. Aspects related to RH documentation, overall maintenance strategy and design concepts for optimizing the maintainability of the UL are presented

Quality assurance for the maintenance of nuclear power plants

International Nuclear Information System (INIS)

Modemann, G.

1985-01-01

In order to maintain the quality of a nuclear power plant, it is essential that the numerous participants involved in maintenance work consistently fulfil their specified tasks, and that the quality control circuit is closed and functions smoothly. First of all, the report briefly explains the significance of the operational organization of a nuclear power plant and the role of the supervisory authority with the consulted experts. The quality control circuit for maintenance illustrates the tasks and cooperation of the participants. An idea is given of the testing and monitoring criteria which are implemented to assure the quality of the different types of maintenance and the procurement of supplies. (orig.) [de

Opportunistic or event-driven maintenance at the Stanford Linear Accelerator Center

International Nuclear Information System (INIS)

Allen, C.W.; Anderson, S.; Erickson, R.; Linebarger, W.; Sheppard, J.C.; Stanek, M.

1997-03-01

The Stanford Linear Accelerator Center (SLAC) uses a maintenance management philosophy that is best described as opportunistic or event-driven. Opportunistic maintenance can be defined as a systematic method of collecting, investigating, pre-planning, and publishing a set of proposed maintenance tasks and acting on them when there is an unscheduled failure or repair ''opportunity''. Opportunistic maintenance can be thought of as a modification of the run-to-fail maintenance management philosophy. This maintenance plan was adopted and developed to improve the overall availability of SLAC's linear accelerator, beam delivery systems, and associated controls, power systems, and utilities. In the late 1980's, as the technical complexity of the accelerator facility increased, variations on a conventional maintenance plan were used with mixed results. These variations typically included some type of regular periodic interruption to operations. The periodic shutdowns and unscheduled failures were additive and resulted in unsatisfactory availability. Maintenance issues are evaluated in a daily meeting that includes the accelerator managers, maintenance supervisors and managers, safety office personnel, program managers, and accelerator operators. Lists of pending maintenance tasks are made available to the general SLAC population by a World Wide Web site on a local internet. A conventional information system which pre-dates the WWW site is still being used to provide paper copies to groups that are not yet integrated into the WWW system. The local internet provides real time maintenance information, allowing people throughout the facility to track progress on tasks with essentially real-time status updates. With the introduction of opportunistic maintenance, the accelerator's availability has been measurably better. This paper will discuss processes, rolls and responsibilities of key maintenance groups, and management tools developed to support opportunistic maintenance

MO-A-BRB-03: Integration Issues in Electronic Charting for External Beam Therapy

International Nuclear Information System (INIS)

Sutlief, S.

2015-01-01

The process of converting to an electronic chart for radiation therapy can be daunting. It requires a dedicated committee to first research and choose appropriate software, to review the entire documentation policy and flow of the clinic, to convert this system to electronic form or if necessary, redesign the system to more easily conform to the electronic process. Those making the conversion and those who already use electronic charting would benefit from the shared experience of those who have been through the process in the past. Therefore TG262 was convened to provide guidance on electronic charting for external beam radiation therapy and brachytherapy. This course will present the results of an internal survey of task group members on EMR practices in External Beam Radiation Therapy as well as discuss important issues in EMR development and structure for both EBRT and brachytherapy. Learning Objectives: Be familiarized with common practices and pitfalls in development and maintenance of an electronic chart in Radiation Oncology Be familiarized with important issues related to electronic charting in External Beam Radiation Therapy Be familiarized with important issues related to electronic charting in Brachytherapy

Effectiveness of external cues to facilitate task performance in people with neurological disorders: a systematic review and meta-analysis.

Science.gov (United States)

Harrison, Stephanie L; Laver, Kate E; Ninnis, Kayla; Rowett, Cherie; Lannin, Natasha A; Crotty, Maria

2018-03-09

To examine in people with neurological disorders, which method/s of providing external cues to improve task performance are most effective. Medline, EMBASE, and PsycINFO were systematically searched. Two reviewers independently screened, extracted data, and assessed the quality of the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE). Twenty six studies were included. Studies examined a wide-range of cues including visual, tactile, auditory, verbal, and multi-component cues. Cueing (any type) improved walking speed when comparing cues to no cues (mean difference (95% confidence interval): 0.08 m/s (0.06-0.10), I 2  = 68%, low quality of evidence). Remaining evidence was analysed narratively; evidence that cueing improves activity-related outcomes was inconsistent and rated as very low quality. It was not possible to determine which form of cueing may be more effective than others. Providing cues to encourage successful task performance is a core component of rehabilitation, however there is limited evidence on the type of cueing or which tasks benefit most from external cueing. Low-quality evidence suggests there may be a beneficial effect of cueing (any type) on walking speed. Sufficiently powered randomised controlled trials are needed to inform therapists of the most effective cueing strategies to improve activity performance in populations with a neurological disorder. Implications for rehabilitation Providing cues is a core component of rehabilitation and may improve successful task performance and activities in people with neurological conditions including stroke, Parkinson's disease, Alzheimer's disease, traumatic brain injury, and multiple sclerosis, but evidence is limited for most neurological conditions with much research focusing on stroke and Parkinson's disease. Therapists should consider using a range of different types of cues depending on the aims of treatment and the neurological condition. There is

A Study on Human Factors in Maintenance of a Nuclear Power Plant (NPP)

International Nuclear Information System (INIS)

Park, Young Ho; Seong, Poong Hyun

2006-01-01

In human factors research, more attention has been devoted to the operation of a nuclear power plant (NPP) than to their maintenance. However, more NPP incidents are caused by inadequate maintenance rather than by faulty operation. There is a trend in NPP toward introducing digital technology into safety and non-safety systems. This lead to changes of maintenance, and support systems such as diagnosis system, augmentation system and handy terminal will be developed. In this context, it is important to identify tasks of human related to each phase of maintenance and their relation in order to apply those to maintenance. However, there are few researches of human factors in maintenance. This paper studies on framework of cognitive task analysis for developing maintenance support systems

A Taxonomy for Heavy-Duty Telemanipulation Tasks Using Elemental Actions

Directory of Open Access Journals (Sweden)

Alexander Owen-Hill

2013-10-01

Full Text Available In the maintenance of large scientific facilities, telemanipulation procedures can involve various subprocedures which in turn are made up of a sequence of subtasks. This work presents a taxonomy which describes a set of elemental actions for heavy-duty telemanipulation, along with an example of these actions in a standard maintenance subprocedure. As maintenance tasks are often very different at high-level, this generalized way of deconstructing tasks allows a highly adaptable approach to describe the sequence of any procedure, which can then be used for such applications as task monitoring, automation or detection of incomplete tasks. We describe in detail the properties of each elemental action and apply the taxonomy to an example subprocedure to show how the process can be generalizable. An automatic state-machine creation stage is shown, which would be used at the task scheduling stage to simplify calculations carried out during the moment-by-moment execution of the task.

The-Abstraction-Hierarchy-based Mobile PC Display Design for NPP Maintenance

International Nuclear Information System (INIS)

Kim, In; Kim, Bo Gyung; Seong, Poong Hyun; Ha, Jun Su

2010-01-01

Recently, the importance of effective maintenance in nuclear power plants (NPPs) has been emphasized and research into effective maintenance by adopting mobile maintenance aids (MMAs) have been attempted. For improved and effective use of an MMA display design method based on abstraction hierarchy (AH) is proposed and its design considerations are discussed in this study. Six levels of abstraction hierarchy are proposed in this paper to classify the maintenance information. By classifying and organizing maintenance information using AH, maintenance information can be used effectively by users with either high or low levels of expertise. When information classification has been finished, the information for MMA design is selected and designed. With the considerations of MMA design analysis and guidelines, AH-based MMA is designed for the maintenance tasks. An experiment is conducted using the AH-based MMA in order to estimate the effectiveness of the proposed method for the maintenance tasks and to identify design considerations to enhance the proposed MMAs. The result indicated that an AH-based manual was more effective than a conventional manual in terms of task completion time and number of errors. The workload for the AH-based manual was estimated less than the conventional manual for subjects with low level of expertise. As the level of expertise increases, subjects tended to follow more abstract information while the number of navigations decreased. It is believed that when mobile devices become pervasive in NPP maintenance fields, AH-model applied MMAs can be used as an effective maintenance supporting tool

Maintenance evaluation using risk based criteria

International Nuclear Information System (INIS)

Torres Valle, A.

1996-01-01

The maintenance evaluation is currently performed by using economic and, in some case, technical equipment failure criteria, however this is done to a specific equipment level. In general, when statistics are used the analysis for maintenance optimization are made isolated and whit a post mortem character; The integration provided by mean of Probabilistic Safety assessment (PSA) together with the possibilities of its applications, allow for evaluation of maintenance on the basis of broader scope criteria in regard to those traditionally used. The evaluate maintenance using risk based criteria, is necessary to follow a dynamic and systematic approach, in studying the maintenance strategy, to allow for updating the initial probabilistic models, for including operational changes that often take place during operation of complex facilities. This paper proposes a dynamic evaluation system of maintenance task. The system is illustrated by means of a practical example

Proposing New Heuristic Approaches for Preventive Maintenance Scheduling

Directory of Open Access Journals (Sweden)

majid Esmailian

2013-08-01

Full Text Available The purpose of preventive maintenance management is to perform a series of tasks that prevent or minimize production breakdowns and improve reliability of production facilities. An important objective of preventive maintenance management is to minimize downtime of production facilities. In order to accomplish this objective, personnel should efficiently allocate resources and determine an effective maintenance schedule. Gopalakrishnan (1997 developed a mathematical model and four heuristic approaches to solve the preventive maintenance scheduling problem of assigning skilled personnel to work with tasks that require a set of corresponding skills. However, there are several limitations in the prior work in this area of research. The craft combination problem has not been solved because the craft combination is assumed as given. The craft combination problem concerns the computation of all combinations of assigning multi skilled workers to accomplishment of a particular task. In fact, determining craft combinations is difficult because of the exponential number of craft combinations that are possible. This research provides a heuristic approach for determining the craft combination and four new heuristic approach solution for the preventive maintenance scheduling problem with multi skilled workforce constraints. In order to examine the new heuristic approach and to compare the new heuristic approach with heuristic approach of Gopalakrishnan (1997, 81 standard problems have been generated based on the criterion suggested by from Gopalakrishnan (1997. The average solution quality (SQ of the new heuristic approaches is 1.86% and in old heuristic approaches is 8.32%. The solution time of new heuristic approaches are shorter than old heuristic approaches. The solution time of new heuristic approaches is 0.78 second and old heuristic approaches is 6.43 second, but the solution time of mathematical model provided by Gopalakrishnan (1997 is 152 second. �

Working Memory as Internal Attention: Toward an Integrative Account of Internal and External Selection Processes

Science.gov (United States)

Kiyonaga, Anastasia; Egner, Tobias

2012-01-01

Working memory (WM) and attention have been studied as separate cognitive constructs, although it has long been acknowledged that attention plays an important role in controlling the activation, maintenance, and manipulation of representations in WM. WM has, conversely, been thought of as a means of maintaining representations to voluntarily guide perceptual selective attention. It has more recently been observed, however, that the contents of WM can capture visual attention, even when such internally maintained representations are irrelevant, and often disruptive, to the immediate external task. Thus the precise relationship between WM and attention remains unclear, but it appears that they may bi-directionally impact one another, whether or not internal representations are consistent with external perceptual goals. This reciprocal relationship seems, further, to be constrained by limited cognitive resources to handle demands in either maintenance or selection. We propose here that the close relationship between WM and attention may be best described as a give-and-take interdependence between attention directed toward actively maintained internal representations (traditionally considered WM) versus external perceptual stimuli (traditionally considered selective attention), underpinned by their shared reliance on a common cognitive resource. Put simply, we argue that WM and attention should no longer be considered as separate systems or concepts, but as competing and impacting one another because they rely on the same limited resource. This framework can offer an explanation for the capture of visual attention by irrelevant WM contents, as well as a straightforward account of the underspecified relationship between WM and attention. PMID:23233157

Working memory as internal attention: toward an integrative account of internal and external selection processes.

Science.gov (United States)

Kiyonaga, Anastasia; Egner, Tobias

2013-04-01

Working memory (WM) and attention have been studied as separate cognitive constructs, although it has long been acknowledged that attention plays an important role in controlling the activation, maintenance, and manipulation of representations in WM. WM has, conversely, been thought of as a means of maintaining representations to voluntarily guide perceptual selective attention. It has more recently been observed, however, that the contents of WM can capture visual attention, even when such internally maintained representations are irrelevant, and often disruptive, to the immediate external task. Thus, the precise relationship between WM and attention remains unclear, but it appears that they may bidirectionally impact one another, whether or not internal representations are consistent with the external perceptual goals. This reciprocal relationship seems, further, to be constrained by limited cognitive resources to handle demands in either maintenance or selection. We propose here that the close relationship between WM and attention may be best described as a give-and-take interdependence between attention directed toward either actively maintained internal representations (traditionally considered WM) or external perceptual stimuli (traditionally considered selective attention), underpinned by their shared reliance on a common cognitive resource. Put simply, we argue that WM and attention should no longer be considered as separate systems or concepts, but as competing and influencing one another because they rely on the same limited resource. This framework can offer an explanation for the capture of visual attention by irrelevant WM contents, as well as a straightforward account of the underspecified relationship between WM and attention.

Is a Responsive Default Mode Network Required for Successful Working Memory Task Performance?

Science.gov (United States)

Čeko, Marta; Gracely, John L.; Fitzcharles, Mary-Ann; Seminowicz, David A.; Schweinhardt, Petra

2015-01-01

In studies of cognitive processing using tasks with externally directed attention, regions showing increased (external-task-positive) and decreased or “negative” [default-mode network (DMN)] fMRI responses during task performance are dynamically responsive to increasing task difficulty. Responsiveness (modulation of fMRI signal by increasing load) has been linked directly to successful cognitive task performance in external-task-positive regions but not in DMN regions. To investigate whether a responsive DMN is required for successful cognitive performance, we compared healthy human subjects (n = 23) with individuals shown to have decreased DMN engagement (chronic pain patients, n = 28). Subjects performed a multilevel working-memory task (N-back) during fMRI. If a responsive DMN is required for successful performance, patients having reduced DMN responsiveness should show worsened performance; if performance is not reduced, their brains should show compensatory activation in external-task-positive regions or elsewhere. All subjects showed decreased accuracy and increased reaction times with increasing task level, with no significant group differences on either measure at any level. Patients had significantly reduced negative fMRI response (deactivation) of DMN regions (posterior cingulate/precuneus, medial prefrontal cortex). Controls showed expected modulation of DMN deactivation with increasing task difficulty. Patients showed significantly reduced modulation of DMN deactivation by task difficulty, despite their successful task performance. We found no evidence of compensatory neural recruitment in external-task-positive regions or elsewhere. Individual responsiveness of the external-task-positive ventrolateral prefrontal cortex, but not of DMN regions, correlated with task accuracy. These findings suggest that a responsive DMN may not be required for successful cognitive performance; a responsive external-task-positive network may be sufficient

Attention modulates maintenance of representations in visual short-term memory.

Science.gov (United States)

Kuo, Bo-Cheng; Stokes, Mark G; Nobre, Anna Christina

2012-01-01

Recent studies have shown that selective attention is of considerable importance for encoding task-relevant items into visual short-term memory (VSTM) according to our behavioral goals. However, it is not known whether top-down attentional biases can continue to operate during the maintenance period of VSTM. We used ERPs to investigate this question across two experiments. Specifically, we tested whether orienting attention to a given spatial location within a VSTM representation resulted in modulation of the contralateral delay activity (CDA), a lateralized ERP marker of VSTM maintenance generated when participants selectively encode memory items from one hemifield. In both experiments, retrospective cues during the maintenance period could predict a specific item (spatial retrocue) or multiple items (neutral retrocue) that would be probed at the end of the memory delay. Our results revealed that VSTM performance is significantly improved by orienting attention to the location of a task-relevant item. The behavioral benefit was accompanied by modulation of neural activity involved in VSTM maintenance. Spatial retrocues reduced the magnitude of the CDA, consistent with a reduction in memory load. Our results provide direct evidence that top-down control modulates neural activity associated with maintenance in VSTM, biasing competition in favor of the task-relevant information.

Risk analysis of external radiation therapy

International Nuclear Information System (INIS)

Arvidsson, Marcus

2011-09-01

External radiation therapy is carried out via a complex treatment process in which many different groups of staff work together. Much of the work is dependent on and in collaboration with advanced technical equipment. The purpose of the research task has been to identify a process for external radiation therapy and to identify, test and analyze a suitable method for performing risk analysis of external radiation therapy

Computer assisted procedure maintenance

International Nuclear Information System (INIS)

Bisio, R.; Hulsund, J. E.; Nilsen, S.

2004-04-01

The maintenance of operating procedures in a NPP is a tedious and complicated task. Through the whole life cycle of the procedures they will be dynamic, 'living' documents. Several aspects of the procedure must be considered in a revision process. Pertinent details and attributes of the procedure must be checked. An organizational structure must be created and responsibilities allotted for drafting, revising, reviewing and publishing procedures. Available powerful computer technology provides solutions within document management and computerisation of procedures. These solutions can also support the maintenance of procedures. Not all parts of the procedure life cycle are equally amenable to computerized support. This report looks at the procedure life cycle in todays NPPs and discusses the possibilities associated with introduction of computer technology to assist the maintenance of procedures. (Author)

Software protocol design: Communication and control in a multi-task robot machine for ITER vacuum vessel assembly and maintenance

International Nuclear Information System (INIS)

Li, Ming; Wu, Huapeng; Handroos, Heikki; Yang, Guangyou; Wang, Yongbo

2015-01-01

applying these protocols, the software for a multi-task robot machine that is used for ITER vacuum vessel assembly and maintenance has been developed and it is demonstrated that machining tasks of the robot machine, such as milling, drilling, welding etc., can be implemented in both an individual and composite way.

Software protocol design: Communication and control in a multi-task robot machine for ITER vacuum vessel assembly and maintenance

Energy Technology Data Exchange (ETDEWEB)

Li, Ming, E-mail: ming.li@lut.fi [Laboratory of Intelligent Machines, Lappeenranta University of Technology (Finland); Wu, Huapeng; Handroos, Heikki [Laboratory of Intelligent Machines, Lappeenranta University of Technology (Finland); Yang, Guangyou [School of Mechanical Engineering, Hubei University of Technology, Wuhan (China); Wang, Yongbo [Laboratory of Intelligent Machines, Lappeenranta University of Technology (Finland)

2015-10-15

applying these protocols, the software for a multi-task robot machine that is used for ITER vacuum vessel assembly and maintenance has been developed and it is demonstrated that machining tasks of the robot machine, such as milling, drilling, welding etc., can be implemented in both an individual and composite way.

76 FR 81009 - Aviation Rulemaking Advisory Committee-New Task

Science.gov (United States)

2011-12-27

... Committee--New Task AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of new task... Rulemaking Advisory Committee (ARAC) a new task to develop a comprehensive program of voluntary accreditation... maintenance program (CAMP). This task addresses, in part, the ARAC recommendation developed by the Commercial...

MAPPS (Maintenance Personnel Performance Simulation): a computer simulation model for human reliability analysis

International Nuclear Information System (INIS)

Knee, H.E.; Haas, P.M.

1985-01-01

A computer model has been developed, sensitivity tested, and evaluated capable of generating reliable estimates of human performance measures in the nuclear power plant (NPP) maintenance context. The model, entitled MAPPS (Maintenance Personnel Performance Simulation), is of the simulation type and is task-oriented. It addresses a number of person-machine, person-environment, and person-person variables and is capable of providing the user with a rich spectrum of important performance measures including mean time for successful task performance by a maintenance team and maintenance team probability of task success. These two measures are particularly important for input to probabilistic risk assessment (PRA) studies which were the primary impetus for the development of MAPPS. The simulation nature of the model along with its generous input parameters and output variables allows its usefulness to extend beyond its input to PRA

Maintenance considerations of the Starfire Commercial Tokamak

International Nuclear Information System (INIS)

Trachael, C.A.; Zahn, H.S.; Field, R.E.; Stevens, H.C.

1979-01-01

An initial reactor design has been developed for the Starfire Tokamak reactor that incorporates maintenance features to permit reactor and plant operation with a 75% availability. All components of the reactor can be replaced utilizing highly automated remote maintenance techniques. Provisions for contact maintenance are included but would only be utilized on a contingency basis since it is believed that allowable dose rates will be decreased in future years. A modular design approach is used for the reactor and auxiliary subsystems to permit efficient use of remote maintenance. The modular approach minimizes the number of different maintenance operations required and can result in use of simple tasks such as push, pull, turn, etc., maneuvers for module removal. Fault isolation is provided for each replaceable module

Is a Responsive Default Mode Network Required for Successful Working Memory Task Performance?

Science.gov (United States)

Čeko, Marta; Gracely, John L; Fitzcharles, Mary-Ann; Seminowicz, David A; Schweinhardt, Petra; Bushnell, M Catherine

2015-08-19

In studies of cognitive processing using tasks with externally directed attention, regions showing increased (external-task-positive) and decreased or "negative" [default-mode network (DMN)] fMRI responses during task performance are dynamically responsive to increasing task difficulty. Responsiveness (modulation of fMRI signal by increasing load) has been linked directly to successful cognitive task performance in external-task-positive regions but not in DMN regions. To investigate whether a responsive DMN is required for successful cognitive performance, we compared healthy human subjects (n = 23) with individuals shown to have decreased DMN engagement (chronic pain patients, n = 28). Subjects performed a multilevel working-memory task (N-back) during fMRI. If a responsive DMN is required for successful performance, patients having reduced DMN responsiveness should show worsened performance; if performance is not reduced, their brains should show compensatory activation in external-task-positive regions or elsewhere. All subjects showed decreased accuracy and increased reaction times with increasing task level, with no significant group differences on either measure at any level. Patients had significantly reduced negative fMRI response (deactivation) of DMN regions (posterior cingulate/precuneus, medial prefrontal cortex). Controls showed expected modulation of DMN deactivation with increasing task difficulty. Patients showed significantly reduced modulation of DMN deactivation by task difficulty, despite their successful task performance. We found no evidence of compensatory neural recruitment in external-task-positive regions or elsewhere. Individual responsiveness of the external-task-positive ventrolateral prefrontal cortex, but not of DMN regions, correlated with task accuracy. These findings suggest that a responsive DMN may not be required for successful cognitive performance; a responsive external-task-positive network may be sufficient. We studied the

Maintenance related to life management: Survey and control of equipment ageing

International Nuclear Information System (INIS)

Hevia Ruperez, F.

2000-01-01

The aim of this paper is to review relevant objectives and aspects of the Maintenance Evaluation and Improvement Programmes for Nuclear Power Plant Life Management. Recent experience shows that current maintenance practice often fails to directly address long-term degradation that affects singular plant components and equipment populations. Instead, delayed attention to the consequences makes good Life Management unfeasible. This has brought about the need for specific Maintenance Evaluation and Improvement Programmes to adjust to the basic objective of Life Management which is to protect against, mitigate and/or monitor ageing that affects the safe, profitable life of the facility. The paper analyses the methodologies used, incidents during their application and the main conclusions reached from the implementation of these programmes in Spanish nuclear power plants. Special attention is paid to recommended solutions for improving the efficiency of the utility's contributions, its leadership in task development and integration, and its interfaces with organisations specialised in providing services that support Life Management Programmes. The coexistence of these and other similar maintenance programmes make it necessary to integrate tasks to optimise effort and tools. The paper analyses the guidelines to be considered when integrating these Programmes with other maintenance optimisation programmes (economy and feasibility, RCM) and with tasks derived from the application of Maintenance Rule regulatory requirements. Lastly, the paper reports on the state of these Maintenance Evaluation and Improvement Programmes, their development, what prospects they have, and the Industry's initiative and actions concerning the matter. (author)

Service for maintenance of electronic equipment of the RA reactor, Report for 1977 - Annex IV

International Nuclear Information System (INIS)

Milosevic, M.

1977-01-01

This report describes the tasks and organizational structure of the Service for maintenance of electronic equipment of the RA reactor. The most important task of this Service is control and maintenance of the reactor control and protection instruments, operation control, and dosimetry system. Besides data about this basic instrumentation, the report includes data about control and maintenance of other electronic equipment related to the experimental devices [sr

CaMKII Requirement for in Vivo Insular Cortex LTP Maintenance and CTA Memory Persistence

Directory of Open Access Journals (Sweden)

Yectivani Juárez-Muñoz

2017-11-01

Full Text Available Calcium-calmodulin/dependent protein kinase II (CaMKII plays an essential role in LTP induction, but since it has the capacity to remain persistently activated even after the decay of external stimuli it has been proposed that it can also be necessary for LTP maintenance and therefore for memory persistence. It has been shown that basolateral amygdaloid nucleus (Bla stimulation induces long-term potentiation (LTP in the insular cortex (IC, a neocortical region implicated in the acquisition and retention of conditioned taste aversion (CTA. Our previous studies have demonstrated that induction of LTP in the Bla-IC pathway before CTA training increased the retention of this task. Although it is known that IC-LTP induction and CTA consolidation share similar molecular mechanisms, little is known about the molecular actors that underlie their maintenance. The purpose of the present study was to evaluate the role of CaMKII in the maintenance of in vivo Bla-IC LTP as well as in the persistence of CTA long-term memory (LTM. Our results show that acute microinfusion of myr-CaMKIINtide, a selective inhibitor of CaMKII, in the IC of adult rats during the late-phase of in vivo Bla-IC LTP blocked its maintenance. Moreover, the intracortical inhibition of CaMKII 24 h after CTA acquisition impairs CTA-LTM persistence. Together these results indicate that CaMKII is a central key component for the maintenance of neocortical synaptic plasticity as well as for persistence of CTA-LTM.

Preventive maintenance basis: Volume 1 -- Air-operated valves. Final report

International Nuclear Information System (INIS)

Worledge, D.; Hinchcliffe, G.

1997-07-01

US nuclear plants are implementing preventive maintenance (PM) tasks with little documented basis beyond fundamental vendor information to support the tasks or their intervals. The Preventive Maintenance Basis project provides utilities with the technical basis for PM tasks and task intervals associated with 40 specific components such as valves, electric motors, pumps, and HVAC equipment. This report provides an overview of the PM Basis project and describes use of the PM Basis database. This document provides a program of PM tasks suitable for application to Air Operated Valves (AOV's) in nuclear power plants. The PM tasks that are recommended provide a cost-effective way to intercept the causes and mechanisms that lead to degradation and failure. They can be used, in conjunction with material from other sources, to develop a complete PM program or to improve an existing program. Users of this information will be utility managers, supervisors, craft technicians, and training instructors responsible for developing, optimizing, or fine-tuning PM programs

External Data and Attribute Hyperlink Programs for Promis*e(Registered Trademark)

Science.gov (United States)

Derengowski, Rich; Gruel, Andrew

2001-01-01

External Data and Attribute Hyperlink are computer programs that can be added to Promis*e(trademark) which is a commercial software system that automates routine tasks in the design (including drawing schematic diagrams) of electrical control systems. The programs were developed under the Stennis Space Center's (SSC) Dual Use Technology Development Program to provide capabilities for SSC's BMCS configuration management system which uses Promis*e(trademark). The External Data program enables the storage and management of information in an external database linked to a drawing. Changes can be made either in the database or on the drawing. Information that originates outside Promis*e(trademark) can be stored in custom fields that can be added to the database. Although this information is not available in Promis*e(trademark) printed drawings, it can be associated with symbols in the drawings, and can be retrieved through the drawings when the software is running. The Attribute Hyperlink program enables the addition of hyperlink information as attributes of symbols. This program enables the formation of a direct hyperlink between a schematic diagram and an Internet site or a file on a compact disk, on the user's hard drive, or on another computer on a network to which the user's computer is connected. The user can then obtain information directly related to the part (e.g., maintenance, or troubleshooting information) associated with the hyperlink.

Maintenance Maneuver Automation for an Adapted Cylindrical Shape TEC

Directory of Open Access Journals (Sweden)

Rafael Morales

2016-09-01

Full Text Available Several manufacturers have developed devices with which to harness tidal/current power in areas where the depth does not exceed 40 m. These are the so-called first generation Tidal Energy Converters (TEC, and they are usually fixed to the seabed by gravity. When carrying out maintenance tasks on these devices it is, therefore, necessary to remove the nacelles from their bases and raise them to the surface of the sea. They must subsequently be placed back on their bases. These tasks require special high performance ships, signifying high maintenance costs. The automation of emersion and immersion maneuvers will undoubtedly lead to lower costs, given that ships with less demanding requirements will be required for the aforementioned maintenance tasks. This research presents a simple two degrees of freedom dynamic model that can be used to control a first generation TEC that has been conceived of to harness energy from marine currents. The control of the system is carried out by means of a water ballast system located inside the nacelle of the main power unit and is used as an actuator to produce buoying vertical forces. A nonlinear control law based on a decoupling term for the closed loop depth and/or orientation control is also proposed in order to ensure adequate behavior when the TEC performs emersion and immersion maneuvers with only hydrostatic buoyancy forces. The control scheme is composed of an inner loop consisting of a linear and decoupled input/output relationship and the vector of friction and compressibility terms and an outer loop that operates with the tracking error vector in order to ensure the asymptotically exponential stability of the TEC posture. Finally, the effectiveness of the dynamic model and the controller approach is demonstrated by means of numerical simulations when the TEC is carrying out an emersion maneuver for the development of general maintenance tasks and an emersion maneuver for blade-cleaning maintenance

Applying reliability centered maintenance analysis principles to inservice testing

International Nuclear Information System (INIS)

Flude, J.W.

1994-01-01

Federal regulations require nuclear power plants to use inservice test (IST) programs to ensure the operability of safety-related equipment. IST programs are based on American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code requirements. Many of these plants also use Reliability Centered Maintenance (RCM) to optimize system maintenance. ASME Code requirements are hard to change. The process for requesting authority to use an alternate strategy is long and expensive. The difficulties of obtaining this authority make the use of RCM method on safety-related systems not cost effective. An ASME research task force on Risk Based Inservice Testing is investigating changing the Code. The change will allow plants to apply RCM methods to the problem of maintenance strategy selection for safety-related systems. The research task force is working closely with the Codes and Standards sections to develop a process related to the RCM process. Some day plants will be able to use this process to develop more efficient and safer maintenance strategies

Optimizing preventive maintenance

International Nuclear Information System (INIS)

DiCola, F.E.

1988-01-01

The traditional approach to preventive maintenance (PM) is based on adherence to manufacturers's requirements and recommended frequencies. When equipment fails, either new procedures are established or the frequency is increased. This leads to an increase in the number of PM activities, overloading not only maintenance resources, but support as well. There is no correlation between more PM and an increase in equipment reliability. More PM may actually induce failures. Reliability-centered maintenance, a new concept in utility maintenance, is based on identifying system/subsystem functions, failures, and dominant failure modes to develop or revise PM tasks. The activities described in this paper are based on actual implementation of this concept on an ongoing project to upgrade the PM program at one of the largest electric utilities in the country. Optimum PM activities are those that, when implemented, will minimize factors that c cause equipment to fail. One technique described illustrates how equipment performance, failure modes, and causes can be related to minimize the occurrence of failures. Operating history and service life of a component are key factors in determining the most effective PM activities, provided that the factors are related to failure modes and causes

External flood probabilistic safety analysis of a coastal NPP

International Nuclear Information System (INIS)

Pisharady, Ajai S.; Chakraborty, M.K.; Acharya, Sourav; Roshan, A.D.; Bishnoi, L.R.

2015-01-01

External events pose a definitive challenge to safety of NPP, solely due to their ability to induce common cause failures. Flooding incidents at Le Blayais NPP, France, Fort Calhoun NPP, USA and Fukushima Daiichi have pointed to the importance of external flooding as an important contributor to NPP risk. A methodology developed for external flood PSA of a coastal NPP vulnerable to flooding due to tsunami, cyclonic storm and intense local precipitation is presented in this paper. Different tasks for EFPSA has been identified along with general approach for completing each task

Maintenance for life management

International Nuclear Information System (INIS)

Hevia, F.

1997-01-01

Life Management is based on the detection, monitoring and control of long-term degradation that affects individual plant components and important populations. Experience has shown that in many cases current maintenance practices do not attend to ageing directly; instead they deal with the consequences when it is already too late, when good Life Management is no longer practical. This has brought about the need for specific Maintenance Evaluation and Improvement Programmes to adjust to the basic objective of Life Management which is to project against, monitor and mitigate ageing that can affect the safe and profitable operating life of the facility. New regulatory requirements for ageing monitoring and effective maintenance to ensure safety (Maintenance Rule) have made it even more necessary to implement the Maintenance Evaluation Programme to cope with ageing, and to integrate that tasks in both programmes to optimise effort and use of tools. This paper presents a brief description of the objectives and methodologies of these Programmes which has been applied to plants around the world and in Spain at the Garona and Vandellos II plants in Spain as part of the PIE project for developing a Remanent Life Evaluation System for nuclear power plants. (Author)

[The maintenance of automatic analysers and associated documentation].

Science.gov (United States)

Adjidé, V; Fournier, P; Vassault, A

2010-12-01

The maintenance of automatic analysers and associated documentation taking part in the requirements of the ISO 15189 Standard and the French regulation as well have to be defined in the laboratory policy. The management of the periodic maintenance and documentation shall be implemented and fulfilled. The organisation of corrective maintenance has to be managed to avoid interruption of the task of the laboratory. The different recommendations concern the identification of materials including automatic analysers, the environmental conditions to take into account, the documentation provided by the manufacturer and documents prepared by the laboratory including procedures for maintenance.

Analyse of Maintenance Cost in ST

CERN Document Server

Jenssen, B W

2001-01-01

An analyse has been carried out in ST concerning the total costs for the division. Even though the target was the maintenance costs in ST, the global budget over has been analysed. This has been done since there is close relation between investments & consolidation and the required level for maintenance. The purpose of the analyse was to focus on maintenance cost in ST as a ratio of total maintenance costs over the replacement value of the equipment, and to make some comparisons with other industries and laboratories. Families of equipment have been defined and their corresponding ratios calculated. This first approach gives us some "quantitative" measurements. This analyse should be combined with performance indicators (more "qualitative" measurements) that are telling us how well we are performing. This will help us in defending our budget, make better priorities, and we will satisfy the requirements from our external auditors.

Multiple Learning Strategies Project. Building Maintenance & Engineering. Visually Impaired.

Science.gov (United States)

Smith, Dwight; And Others

This instructional package is designed for visually impaired students in the vocational area of building maintenance and engineering. The twenty-eight learning modules are organized into six units: floor care, general maintenance tasks; restrooms; carpet care; power and hand tools; and cabinet construction. Each module, printed in large block…

Virtual maintenance technology for reactor system based on PPR technology

International Nuclear Information System (INIS)

Wu Yaxiang; Ma Baiyong

2009-01-01

Based on the Product, Process and Resources (PPR) technology, the establishing technology of virtual maintenance environment for the reactor system and the process structure tree for virtual maintenance is studied, and the flow for the maintainability design and simulation for reactor system is put forward. Based on the subsection simulation of maintenance process and layered design of maintenance actions, the leveled structure of the reactor system virtual maintenance task is studied. The relation for the data of product, process and resource is described by Plan Evaluation and Review Technology (PERT) diagram to define the maintenance operation. (authors)

SUMO: operation and maintenance management web tool for astronomical observatories

Science.gov (United States)

Mujica-Alvarez, Emma; Pérez-Calpena, Ana; García-Vargas, María. Luisa

2014-08-01

SUMO is an Operation and Maintenance Management web tool, which allows managing the operation and maintenance activities and resources required for the exploitation of a complex facility. SUMO main capabilities are: information repository, assets and stock control, tasks scheduler, executed tasks archive, configuration and anomalies control and notification and users management. The information needed to operate and maintain the system must be initially stored at the tool database. SUMO shall automatically schedule the periodical tasks and facilitates the searching and programming of the non-periodical tasks. Tasks planning can be visualized in different formats and dynamically edited to be adjusted to the available resources, anomalies, dates and other constrains that can arise during daily operation. SUMO shall provide warnings to the users notifying potential conflicts related to the required personal availability or the spare stock for the scheduled tasks. To conclude, SUMO has been designed as a tool to help during the operation management of a scientific facility, and in particular an astronomical observatory. This is done by controlling all operating parameters: personal, assets, spare and supply stocks, tasks and time constrains.

Maintenance for the Millennium: Another Approach

International Nuclear Information System (INIS)

Sculthorpe, Barruy R.

2002-01-01

Nuclear units nationwide are struggling to increase plant reliability and availability while at the same time reduce their operating and maintenance costs. Some very costly investments have been made in programs such as Reliability Centered Maintenance [RCM]. Florida Power and Light's approach at the St. Lucie Nuclear Plant has taken a slightly different approach. Building on our knowledge of the RCM process and an already existing 'World Class' Predictive Maintenance Program, a 'Condition-Based' Maintenance Program that takes advantage of the RCM philosophy and our toolbox full of advanced and highly successful predictive maintenance technologies. These tools currently consist of vibration analysis, lubricant analysis (both physical property and wear metals analysis, thermographic analysis, motor current signature analysis, tribology and process parameter trending. All employed with the intent to evaluate a machines health. This machine health check allows the forecasting of future preventative maintenance [PM's] tasks and the revision of existing PM's to maximize machine performance and eliminate 'no-value-added' maintenance activities/costs. Within the last year, the Condition-Based Maintenance Program has produced a cost saving of approximately $1.5 million dollars. As the program matures, these cost savings will accumulate well into the millennium. (authors)

Susquehanna SES maintenance supervisor training and certification

International Nuclear Information System (INIS)

Deckman, M.

1991-01-01

Susquehanna's program targets all Supervisors, Supervisor Candidates, and Temporary Supervisors that are responsible for in-plant maintenance or maintenance support activities, including: mechanical maintenance; electrical maintenance; maintenance support (labor support, radwaste, etc.); mobile construction support (mechanical and electrical); chemistry; health physics; maintenance planning; and instrument and controls. The program integrates the three major areas of direct Supervisory responsibilities: (1) Leadership and Management - Skills that require interpersonal activities that are typically humanistic and subjective; such as coaching, motivating, communications, etc. (2) Technical and Administrative - Knowledge that is directly related to the job of Supervising from the production, regulatory, accountability perspective. These topics are very objective and include training on topics such as workpackages, plant chemistry parameters, radiological concerns, etc. (3) Technical Skills - Ensure each Supervisor is technically competent in the plant systems, components, or equipment he/she is tasked with maintaining or overseeing. Typical skills found in this area are, circuit breaker maintenance, primary system sampling, or overhauling pumps

RA Reactor operation and maintenance (I-IX), Part I

International Nuclear Information System (INIS)

Zecevic, V.

1963-12-01

The report on RA reactor operation and maintenance for year 1963 is divided in six tasks. This volume contains the introductory report, and three tasks of the final report, namely reactor exploitation, reactivity changes of the RA reactor before repair, planning of refuelling

Preventive maintenance basis: Volume 24 -- Battery -- flooded lead-acid (lead-calcium, lead antimony, plante). Final report

International Nuclear Information System (INIS)

Worledge, D.; Hinchcliffe, G.

1997-12-01

US nuclear power plants are implementing preventive maintenance (PM) tasks with little documented basis beyond fundamental vendor information to support the tasks or their intervals. The Preventive Maintenance Basis project provides utilities with the technical basis for PM tasks and task intervals associated with 40 specific components such as valves, electric motors, pumps, and HVAC equipment. This document provides a program of preventive maintenance tasks suitable for application to flooded lead-acid batteries. The PM tasks that are recommended provide a cost-effective way to intercept the causes and mechanisms that lead to degradation and failure. They can be used in conjunction with material from other sources, to develop a complete PM program or to improve an existing program. This document provides a program of preventive maintenance (PM) tasks suitable for application to flooded lead-acid batteries. The PM tasks that are recommended provide a cost-effective way to intercept the causes and mechanisms that lead to degradation and failure. They can be used, in conjunction with material from other sources, to develop a complete PM program or to improve an existing program. Users of this information will be utility managers, supervisors, system engineers, craft technicians, and training instructors responsible for developing, optimizing, or fine-tuning PM programs

Stroop task among patients with obsessive-compulsive disorder (OCD) and pathological gambling (PG) in methadone maintenance treatment (MMT).

Science.gov (United States)

Peles, Einat; Weinstein, Aviv; Sason, Anat; Adelson, Miriam; Schreiber, Shaul

2014-12-01

To evaluate the impaired attention selection (Stroop interference effect) and general performance [reaction times (RTs)] on the Stroop task among methadone maintenance treatment (MMT) patients with obsessive compulsive disorder (OCD), pathological gambling (PG), both PG/OCD or none, and the influence if having ADHD. Eighty-six patients and 15 control subjects underwent the Stroop task, which measured RTs of condition-related words (color, obsessive compulsive disorder, pathological gambling, addiction) and neutral words. MMT patients had longer RTs on the Stroop task compared with controls. RTs were longer among patients with OCD and in those who abused drugs on the study day. The combined PG/OCD group had the longest RTs, but they were also characterized as abusing more drugs, being older, and having worse cognitive status. Stroop color interference differed only among MMT patients with ADHD, and it was higher among those with OCD than those without OCD. The modified condition-related Stroop did not show any interference effect of OCD, addiction, or gambling words. MMT patients had generally poorer performance, as indicated by longer RTs, that were related to clinical OCD, drug abuse, poor cognitive state, and older age. Patients with both clinical OCD and ADHD had a higher Stroop interference effect, which is a reflection of an attention deficit. In order to improve clinical approach and treatment of MMT patients, OCD and ADHD should be evaluated (and treated as needed).

Task 4.2.2: Task report prepared for the second CRP meeting 5-8 October 1993, Budapest, Hungary

International Nuclear Information System (INIS)

Fujita, Yushi

1993-01-01

This is a preliminary report on Task 4.2.2. of IAEA Coordinated Research Program on Operator Support Systems in Nuclear Power Plants. The purposes of Task 4.2.2 are defined as follows: evaluate functions assigned to operators, maintenance personnel, or plant management staff; identify where operator support systems (OSS) can support those functions in a productive way. In this report, discussion is made of (i) a framework for evaluating functions assigned to operators, maintenance personnel, or plant management staff, and (ii) where OSS can be most beneficial to support these functions. In addition, recommendations for future efforts are made

A New Hybrid Approach for Augmented Reality Maintenance in Scientific Facilities

Directory of Open Access Journals (Sweden)

Héctor Martínez

2013-09-01

Full Text Available Maintenance in scientific facilities is a difficult issue, especially in large and hazardous facilities, due to the complexity of tasks and equipment. Augmented reality is a technology that has already shown great promise in the maintenance field. With the help of augmented reality applications, maintenance tasks can be carried out faster and more safely. The problem with current applications is that they are small-scale prototypes that do not easily scale to large facility maintenance applications. This paper presents a new hybrid approach that enables the creation of augmented reality maintenance applications for large and hazardous scientific facilities. In this paper, a new augmented reality marker and the algorithm for its recognition is proposed. The performance of the algorithm is verified in three test cases, showing promising results in two of them. Improvements in robustness in the third test case in which the camera is moving quickly or when light conditions are extreme are subject to further studies. The proposed new approach will be integrated into an existing augmented reality maintenance system.

RA reactor operation and maintenance in 1992, Part 1

International Nuclear Information System (INIS)

Sotic, O.; Cupac, S.; Sulem, B.; Zivotic, Z.; Majstorovic, D.; Tanaskovic, M.

1992-01-01

During 1992 Ra reactor was not in operation. All the activities were fulfilled according to the previously adopted plan. Basic activities were concerned with revitalisation of the RA reactor and maintenance of reactor components. All the reactor personnel was busy with reconstruction and renewal of the existing reactor systems and building of the new systems, maintenance of the reactor devices. Part of the staff was trained for relevant tasks and maintenance of reactor systems [sr

External noise distinguishes attention mechanisms.

Science.gov (United States)

Lu, Z L; Dosher, B A

1998-05-01

We developed and tested a powerful method for identifying and characterizing the effect of attention on performance in visual tasks as due to signal enhancement, distractor exclusion, or internal noise suppression. Based on a noisy Perceptual Template Model (PTM) of a human observer, the method adds increasing amounts of external noise (white gaussian random noise) to the visual stimulus and observes the effect on performance of a perceptual task for attended and unattended stimuli. The three mechanisms of attention yield three "signature" patterns of performance. The general framework for characterizing the mechanisms of attention is used here to investigate the attentional mechanisms in a concurrent location-cued orientation discrimination task. Test stimuli--Gabor patches tilted slightly to the right or left--always appeared on both the left and the right of fixation, and varied independently. Observers were cued on each trial to attend to the left, the right, or evenly to both stimuli, and decide the direction of tilt of both test stimuli. For eight levels of added external noise and three attention conditions (attended, unattended, and equal), subjects' contrast threshold levels were determined. At low levels of external noise, attention affected threshold contrast: threshold contrasts for non-attended stimuli were systematically higher than for equal attention stimuli, which were, in turn, higher than for attended stimuli. Specifically, when the rms contrast of the external noise is below 10%, there is a consistent 17% elevation of contrast threshold from attended to unattended condition across all three subjects. For higher levels of external noise, attention conditions did not affect threshold contrast values at all. These strong results are characteristic of a signal enhancement, or equivalently, an internal additive noise reduction mechanism of attention.

Electrophysiological signatures of phonological and semantic maintenance in sentence repetition.

Science.gov (United States)

Meltzer, Jed A; Kielar, Aneta; Panamsky, Lilia; Links, Kira A; Deschamps, Tiffany; Leigh, Rosie C

2017-08-01

Verbal short-term memory comprises resources for phonological rehearsal, which have been characterized anatomically, and for maintenance of semantic information, which are less understood. Sentence repetition tasks tap both processes interactively. To distinguish brain activity involved in phonological vs. semantic maintenance, we recorded magnetoencephalography during a sentence repetition task, incorporating three manipulations emphasizing one mechanism over the other. Participants heard sentences or word lists and attempted to repeat them verbatim after a 5-second delay. After MEG, participants completed a cued recall task testing how much they remembered of each sentence. Greater semantic engagement relative to phonological rehearsal was hypothesized for 1) sentences vs. word lists, 2) concrete vs. abstract sentences, and 3) well recalled vs. poorly recalled sentences. During auditory perception and the memory delay period, we found highly left-lateralized activation in the form of 8-30 Hz event-related desynchronization. Compared to abstract sentences, concrete sentences recruited posterior temporal cortex bilaterally, demonstrating a neural signature for the engagement of visual imagery in sentence maintenance. Maintenance of arbitrary word lists recruited right hemisphere dorsal regions, reflecting increased demands on phonological rehearsal. Sentences that were ultimately poorly recalled in the post-test also elicited extra right hemisphere activation when they were held in short-term memory, suggesting increased demands on phonological resources. Frontal midline theta oscillations also reflected phonological rather than semantic demand, being increased for word lists and poorly recalled sentences. These findings highlight distinct neural resources for phonological and semantic maintenance, with phonological maintenance associated with stronger oscillatory modulations. Copyright © 2017 Elsevier Inc. All rights reserved.

External effects in Swiss hydropower

International Nuclear Information System (INIS)

Hauenstein, W.; Bonvin, J.; Vouillamoz, J.

1999-01-01

The article discusses the external costs and benefits of hydropower that are not internalised in normal book-keeping. Several negative and positive effects are discussed. The results of a study that addressed the difficult task of quantifying these external effects are presented. An assessment of the results gained shows that difficulties are to be met regarding system limits, methods of expressing the effects in monetary terms and ethical factors. The report also examines the consideration of external effects as a correction factor for falsified market prices for electricity

Nuclear power plant maintenance personnel reliability prediction (NPP/MPRP) effort at Oak Ridge National Laboratory

International Nuclear Information System (INIS)

Knee, H.E.; Haas, P.M.; Siegel, A.I.

1981-01-01

Human errors committed during maintenance activities are potentially a major contribution to the overall risk associated with the operation of a nuclear power plant (NPP). An NRC-sponsored program at Oak Ridge National Laboratory is attempting to develop a quantitative predictive technique to evaluate the contribution of maintenance errors to the overall NPP risk. The current work includes a survey of the requirements of potential users to ascertain the need for and content of the proposed quantitative model, plus an initial job/task analysis to determine the scope and applicability of various maintenance tasks. In addition, existing human reliability prediction models are being reviewed and assessed with respect to their applicability to NPP maintenance tasks. This paper discusses the status of the program and summarizes the results to date

Amooty, a stair climbing intelligent maintenance robot

Energy Technology Data Exchange (ETDEWEB)

1985-04-01

Toshiba Corporation and a team from Tokyo University have jointly developed a prototype of a mobile, stair climbing intelligent robot, named Amooty, for inspection and maintenance tasks in nuclear power plants.

Discussion on allowed outage time at online maintenance in Japan

International Nuclear Information System (INIS)

Kobayashi, Masahide

2009-01-01

The purpose of this report is clarification of the handling of online maintenance in important system for nuclear safety of nuclear power plant in Japan, and discusses future tasks of online maintenance in Japan. Now, online maintenance is limited few cases in Japan. But, the needs and importance of online maintenance will be increase near future. It is necessary to evaluate safety at the online maintenance, and if necessary PSA results were used. It will be safety to do online maintenance within AOT, but safety of repetition of online maintenance must be evaluated. And, it is necessary to evaluate the influence to which the man-power during year is leveled by OLM. (author)

Preventive maintenance basis: Volume 21 -- HVAC, air handling equipment. Final report

International Nuclear Information System (INIS)

Worledge, D.; Hinchcliffe, G.

1997-12-01

US nuclear plants are implementing preventive maintenance (PM) tasks with little documented basis beyond fundamental vendor information to support the tasks or their intervals. The Preventive Maintenance Basis project provides utilities with the technical basis for PM tasks and task intervals associated with 40 specific components such as valves, electric motors, pumps, and HVAC equipment. This report provides an overview of the PM Basis project and describes use of the PM Basis database. Volume 21 of the report provides a program of PM tasks suitable for application to HVAC-Air Handling Equipment. The PM tasks that are recommended provide a cost-effective way to intercept the causes and mechanisms that lead to degradation and failure. They can be used, in conjunction with material from other sources, to develop a complete PM program or to improve an existing program. Users of this information will be utility managers, supervisors, craft technicians, and training instructors responsible for developing, optimizing, or fine-tuning PM programs

Preventive maintenance basis: Volume 15 -- Rotary screw air compressors. Final report

International Nuclear Information System (INIS)

Worledge, D.; Hinchcliffe, G.

1997-07-01

US nuclear plants are implementing preventive maintenance (PM) tasks with little documented basis beyond fundamental vendor information to support the tasks or their intervals. The Preventive Maintenance Basis project provides utilities with the technical basis for PM tasks and task intervals associated with 40 specific components such as valves, electric motors, pumps, and HVAC equipment. This report provides an overview of the PM Basis project and describes use of the PM Basis database. Volume 15 of the report provides a program of PM tasks suitable for application to rotary screw air compressors in nuclear power plants. The PM tasks that are recommended provide a cost-effective way to intercept the causes and mechanisms that lead to degradation and failure. They can be used, in conjunction with material from other sources, to develop a complete PM program or to improve an existing program. Users of this information will be utility managers, supervisors, craft technicians, and training instructors responsible for developing, optimizing, or fine-tuning PM programs

Amooty, a stair climbing intelligent maintenance robot

International Nuclear Information System (INIS)

Anon.

1985-01-01

Toshiba Corporation and a team from Tokyo University have jointly developed a prototype of a mobile, stair climbing intelligent robot, named Amooty, for inspection and maintenance tasks in nuclear power plants. (author)

Electric motor predictive and preventive maintenance guide

International Nuclear Information System (INIS)

Oliver, J.A.

1992-07-01

Electric motor performance is vital to the reliable and efficient operation of power plants. The failure of one or more critical motors could cause lost capacity and excessive repair and maintenance cost. However, existing maintenance recommendations proposed by vendors for electric motors have sometimes encouraged many overly conservative maintenance practices. These practices have lead to excessive maintenance activities and costs which have provided no extra margin of operability. EPRI has sponsored RP2814-35 to develop a guide which provides power plants with information and guidance for establishing an effective maintenance program which will aid in preventing unexpected motor failures and assist in planning motor maintenance efforts. The guide includes a technical description which summarizes technical data relative to the four basic types of motors and their components in general use in power plants. The significant causes of motor failures are investigated and described in detail and methods to optimize service life and minimize maintenance cost through appropriate preventive maintenance and conditioning program are presented. This guide provides a foundation for an effective electric motor maintenance program and simplifies the selection of predictive and preventive maintenance tasks. Its use will enable maintenance personnel in nuclear and fossil plants to plan motor repairs during scheduled outages and avoid costly unexpected failures

Design and evaluation of augmented reality for nuclear power plant maintenance based on Cognitive activity analysis

International Nuclear Information System (INIS)

Koo, Jwa Jin

2008-02-01

The goals of maintenance in nuclear power plants (NPPs) are to reduce the number of plant shutdowns, to decrease the shutdown time, to minimize the maintenance costs, and to improve nuclear safety. Furthermore, it is difficult for maintenance personnel to conduct work in NPPs due to the complexity of NPPs, safety issues and time constraints. Human errors should be prevented to achieve maintenance goals in NPPs. Therefore, it is necessary to improve working conditions by introducing support systems. Augmented Reality (AR) has the potential to assist with maintenance tasks and make maintenance personnel concentrate on the tasks, which will then the reduced human error and improve human performance. The working procedure for AR systems was designed based on the characteristics of cognitive activity, and an experiment was conducted to estimate the effectiveness of AR. The results indicated that a well-designed working procedure for AR systems was more effective than a conventional paper-based working procedure. In addition, participants made fewer errors using the designed working procedure. AR systems as maintenance support systems are beneficial technology that can improve maintenance performance by reducing cognitive loads and unnecessary movements. An AR application can be attractive and effective at supporting maintenance task

The modulation of EEG variability between internally- and externally-driven cognitive states varies with maturation and task performance.

Directory of Open Access Journals (Sweden)

Jessie M H Szostakiwskyj

Full Text Available Increasing evidence suggests that brain signal variability is an important measure of brain function reflecting information processing capacity and functional integrity. In this study, we examined how maturation from childhood to adulthood affects the magnitude and spatial extent of state-to-state transitions in brain signal variability, and how this relates to cognitive performance. We looked at variability changes between resting-state and task (a symbol-matching task with three levels of difficulty, and within trial (fixation, post-stimulus, and post-response. We calculated variability with multiscale entropy (MSE, and additionally examined spectral power density (SPD from electroencephalography (EEG in children aged 8-14, and in adults aged 18-33. Our results suggest that maturation is characterized by increased local information processing (higher MSE at fine temporal scales and decreased long-range interactions with other neural populations (lower MSE at coarse temporal scales. Children show MSE changes that are similar in magnitude, but greater in spatial extent when transitioning between internally- and externally-driven brain states. Additionally, we found that in children, greater changes in task difficulty were associated with greater magnitude of modulation in MSE. Our results suggest that the interplay between maturational and state-to-state changes in brain signal variability manifest across different spatial and temporal scales, and influence information processing capacity in the brain.

Equipment and special tool design for remote maintenance

International Nuclear Information System (INIS)

Northey, L.M.; Thomson, J.D.

1985-01-01

Maintenance tasks performed in locations with hostile environments and/or limited space accesses often require equipment that is operated remotely. This paper discusses considerations that should be addressed in the design of remote maintenance equipment. Some of the topics include proper material selection, interface identifications, operational feedback devices and cost limitations. These considerations add ''human engineering'' to the equipment design to assure protection of the tool and the operating personnel. Examples of remote maintenance and inspection systems that were developed by the Westinghouse Hanford Company and that utilize many of these design considerations are included

Maintenance, endogeneous, respiration, lysis, decay and predation

DEFF Research Database (Denmark)

loosdrecht, Marc C. M. Van; Henze, Mogens

1999-01-01

mechanism is microbiologically correct. The lysis/decay model mechanism is a strongly simplified representation of reality. This paper tries to review the processes grouped under endogenous respiration in activated sludge models. Mechanisms and processes such as maintenance, lysis, internal and external...... decay, predation and death-regeneration are discussed. From recent microbial research it has become evident that cells do not die by themselves. Bacteria are however subject to predation by protozoa. Bacteria store reserve polymers that in absence of external substrate are used for growth...

Building Maintenance. Student Learning Guide.

Science.gov (United States)

Palm Beach County Board of Public Instruction, West Palm Beach, FL.

This student learning guide contains one module for completing a course in building maintenance. It is designed especially for use in secondary schools in Palm Beach County, Florida. The module covers one task, and consists of a purpose, performance objective, enabling objectives, learning activities keyed to resources, information sheets, student…

Planning of Maintenance and Repair of Complicated Technical Systems

Directory of Open Access Journals (Sweden)

N. I. Liseychikov

2004-01-01

Full Text Available It is expedient to use mathematical models for substantiation of operational material consumption at maintenance of complicated technical systems. The appropriate tasks have been considered: minimization of operational material consumption; determination of maximum scope of work to be executed while maintaining one system; optimization of operational material consumption while organizing maintenance of a system group; planning of technical maintenance and determination of a number of systems to be maintained. Formalization and solution of the above problems have been accomplished.

High-definition television evaluation for remote handling task performance

International Nuclear Information System (INIS)

Fujita, Y.; Omori, E.; Hayashi, S.; Draper, J.V.; Herndon, J.N.

1986-01-01

In a plant that employs remote handling techniques for equipment maintenance, operators perform maintenance tasks primarily by using the information from television systems. The efficiency of the television system has a significant impact on remote maintenance task performance. High-definition television (HDTV) transmits a video image with more than twice the number of horizontal scan lines as standard-resolution television (1125 for HDTV to 525 for standard-resolution NTSC television). The added scan lines dramatically improve the resolution of images on the HDTV monitors. This paper describes experiments designed to evaluate the impact of HDTV on the performance of typical remote tasks. The experiments described in this paper compared the performance of four operators using HDTV with their performance while using other television systems. The experiments included four television systems: (a) high-definition color television, (b) high-definition monochromatic television, (c) standard-resolution monochromatic television, and (d) standard-resolution stereoscopic monochromatic television

Ecological Interface Design of Augmented Reality Display for Nuclear Power Plant Maintenance

International Nuclear Information System (INIS)

Kim, In; Seong, Poong Hyun

2008-01-01

The importance of maintenance in nuclear power plants (NPPs) has been emphasized through many researches. The goals of maintenance in nuclear power plants are not only to reduce the number of shutdowns which directly affects to the profit, but also to prevent accidents or incidents hence improves nuclear safety. It is known that reduction of the rate of human error in maintenance tasks can be achieved if maintenance personnel are properly supported by maintenance support systems. Among many proposed maintenance support system, the use of augmented reality (AR) has been proposed

The nuclear power plant maintenance personnel reliability prediction (NPP/MPRP) effort at Oak Ridge National Laboratory

International Nuclear Information System (INIS)

Knee, H.E.; Haas, P.M.; Siegel, A.I.

1982-01-01

Human errors committed during maintenance activities are potentially a major contribution to the overall risk associated with the operation of a nuclear power plant (NPP). An NRC-sponsored program at Oak Ridge National Laboratory is attempting to develop a quantitative predictive technique to evaluate the contribution of maintenance errors to the overall NPP risk. The current work includes a survey of the requirements of potential users to ascertain the need for and content of the proposed quantitative model, plus an initial job/task analysis to determine the scope and applicability of various maintenance tasks. In addition, existing human reliability prediction models are being reviewed and assessed with respect to their applicability to NPP maintenance tasks. This paper discusses the status of the program and summarizes the results to date

Equipment reliability process improvement and preventive maintenance optimization

International Nuclear Information System (INIS)

Darragi, M.; Georges, A.; Vaillancourt, R.; Komljenovic, D.; Croteau, M.

2004-01-01

The Gentilly-2 Nuclear Power Plant wants to optimize its preventive maintenance program through an Integrated Equipment Reliability Process. All equipment reliability related activities should be reviewed and optimized in a systematic approach especially for aging plants such as G2. This new approach has to be founded on best practices methods with the purpose of the rationalization of the preventive maintenance program and the performance monitoring of on-site systems, structures and components (SSC). A rational preventive maintenance strategy is based on optimized task scopes and frequencies depending on their applicability, critical effects on system safety and plant availability as well as cost-effectiveness. Preventive maintenance strategy efficiency is systematically monitored through degradation indicators. (author)

Program strategies for maintenance management, organization and planning

International Nuclear Information System (INIS)

Czegeny, J.I.

2003-01-01

In this paper we look respectively at three specific examples showing program strategies for maintenance management, organization and planning. Starting with preventive maintenance optimization, we will look at one Bruce B Predefined task on the Reactor Regulating System to illustrate reduced maintenance requirement, a maintenance management strategy. Next discussed is the organizational strategy at Darlington to have an engineering program meet the jurisdictional requirements for maintaining certification for TSSA registered pressure vessels. The last look-see will show the earned value of the planning for the first Pickering A unit to be returned to service. Finally all the above is tied together in a compare and contrast of what works and what could be improved upon. (author)

NASA work unit system file maintenance manual

Science.gov (United States)

1972-01-01

The NASA Work Unit System is a management information system for research tasks (i.e., work units) performed under NASA grants and contracts. It supplies profiles on research efforts and statistics on fund distribution. The file maintenance operator can add, delete and change records at a remote terminal or can submit punched cards to the computer room for batch update. The system is designed for file maintenance by a person with little or no knowledge of data processing techniques.

Working memory load and distraction: dissociable effects of visual maintenance and cognitive control.

Science.gov (United States)

Konstantinou, Nikos; Beal, Eleanor; King, Jean-Remi; Lavie, Nilli

2014-10-01

We establish a new dissociation between the roles of working memory (WM) cognitive control and visual maintenance in selective attention as measured by the efficiency of distractor rejection. The extent to which focused selective attention can prevent distraction has been shown to critically depend on the level and type of load involved in the task. High perceptual load that consumes perceptual capacity leads to reduced distractor processing, whereas high WM load that reduces WM ability to exert priority-based executive cognitive control over the task results in increased distractor processing (e.g., Lavie, Trends in Cognitive Sciences, 9(2), 75-82, 2005). WM also serves to maintain task-relevant visual representations, and such visual maintenance is known to recruit the same sensory cortices as those involved in perception (e.g., Pasternak & Greenlee, Nature Reviews Neuroscience, 6(2), 97-107, 2005). These findings led us to hypothesize that loading WM with visual maintenance would reduce visual capacity involved in perception, thus resulting in reduced distractor processing-similar to perceptual load and opposite to WM cognitive control load. Distractor processing was assessed in a response competition task, presented during the memory interval (or during encoding; Experiment 1a) of a WM task. Loading visual maintenance or encoding by increased set size for a memory sample of shapes, colors, and locations led to reduced distractor response competition effects. In contrast, loading WM cognitive control with verbal rehearsal of a random letter set led to increased distractor effects. These findings confirm load theory predictions and provide a novel functional distinction between the roles of WM maintenance and cognitive control in selective attention.

Elements of a total MOV maintenance program

International Nuclear Information System (INIS)

Lavallee, W.L.

1989-01-01

Establishing a good preventive and predictive maintenance program for motor-operated valves (MOVs) is an especially challenging task for nuclear power plants. Because of the sheer number of MOVs involved, all with somewhat different characteristics and requirements, and the extremely critical functions that some of the MOVs perform, the maintenance program quickly becomes a major exercise in coordination. This paper outlines a three-phase approach to achieving a comprehensive MOV maintenance program. It is based on experience in assisting nuclear plants with their MOV programs and encountering many of the pitfalls that can hamper these programs. The three phases include up-front engineering preparation, field diagnostic testing, and maintenance follow-up and trending. Each of these phases is discussed, and a flowchart describing the individual elements of each phase is provided

Maintenance strategy for tilting table of rolling mill based on reliability considerations

International Nuclear Information System (INIS)

Deshpande, V.S.; Modak, J.P.

2003-01-01

Reliability centred maintenance (RCM) is a new strategic framework for ensuring that any asset continues to perform, as its users want it to perform. RCM is a process used to determine the maintenance requirement of any physical asset in its operating context. RCM process entails asking seven questions about each of the selected assets. It makes use of two documents namely, RCM information worksheet and RCM decision worksheet. RCM decision diagram integrates all the decision processes into a single strategic framework. RCM concept developed by US commercial airlines industry has been successfully implemented by Military, Navy, Nuclear power plants, electric power generation and distribution undertakings and several other sectors. These projects have been carried out in the United Kingdom, The Republic of Ireland, the United States, Hong Kong, Australia, Spain and Singapore. The fact that people has enthusiastically received RCM at all levels and has enabled users to achieve some remarkable successes in all of these countries, suggests that it can be universally employed. Literature review indicates that RCM approach is not conventionally applied in process industries in India. Presently, predictive maintenance (PDM) approach along with conventional preventive maintenance is used in continuous/process industries. This approach if implemented in totality will increase the production cost to a large degree and make the production uneconomical. Similarly breakdown maintenance (BDM) approach cannot be applied in such industries as each breakdown involves huge costs. RCM approach is a compromise between PDM and BDM approach for optimising the cost and ensuring the availability of machine. The RCM approach has been applied to the tilting table system of rolling mill for the research work reported in this paper. In the present study, preventive maintenance tasks suggested for power transmission subsystem, guiding and transportation subsystem and hydraulic subsystem in

Using systematic aging assessments to improve effectiveness of plant maintenance programs

International Nuclear Information System (INIS)

Watson, P.; Yang, J.X.; Dam, R.F.; Nickerson, J.H.

2003-01-01

Nuclear plant equipment aging assessment studies provided by AECL include life assessments, condition assessments or systematic assessments of maintenance. AECL has developed several tools to apply the results of aging assessment studies to improve the effectiveness of actual plant maintenance programs. The Systematic Assessment of Maintenance and the SYSTMS tool generate maintenance tasks for a system. The System Maintenance Datastore tool assesses the maintenance resources on a system basis, and can thus quantify the savings realized by optimizing the maintenance program. Long term trends in condition-based maintenance due to component aging can be predicted, and resource savings due to optimum timing of component replacement or general plant refurbishment can be quantified. The System based Adaptive Maintenance Process ensures the maintenance program is continually updated to reflect the latest plant equipment condition and maintenance strategy information. (author)

Payment mechanisms for winter road maintenance services

Directory of Open Access Journals (Sweden)

Adel Abdi

2013-12-01

Full Text Available In countries with severe winters a major part of the annual budget for road maintenance is allocated on performance of winter road maintenance tasks. Finding appropriate remuneration forms to compensate entrepreneurs for performed road measures during winter is not an easy task in order to minimise or eliminate disputes and satisfy both client organisations and contractors. On the other hand improper reimbursement models lead either to the client’s annual budget imbalance due to unnecessary cost overruns or affect contractor’s cash-flow. Such cases in turn affect just-in-time winter road maintenance and then traffic safety. To solve such problems, a number of countries in cold regions like Sweden have developed different remuneration models based more on weather data called Weather Index. Therefore the objective of this paper is to investigate and evaluate the payment models applied in Sweden. The study uses a number of approaches namely; domestic questionnaire survey, analysis of a number of contract documents, a series of meetings with the project managers and an international benchmarking. The study recognised four remuneration models for winter maintenance service of which one based on weather data statistics. The study reveals the payment model based on weather data statistics is only applied for the roads with higher traffic flow and the model generates most uncertainty.

Attention is required for maintenance of feature binding in visual working memory

Science.gov (United States)

Heider, Maike; Husain, Masud

2013-01-01

Working memory and attention are intimately connected. However, understanding the relationship between the two is challenging. Currently, there is an important controversy about whether objects in working memory are maintained automatically or require resources that are also deployed for visual or auditory attention. Here we investigated the effects of loading attention resources on precision of visual working memory, specifically on correct maintenance of feature-bound objects, using a dual-task paradigm. Participants were presented with a memory array and were asked to remember either direction of motion of random dot kinematograms of different colour, or orientation of coloured bars. During the maintenance period, they performed a secondary visual or auditory task, with varying levels of load. Following a retention period, they adjusted a coloured probe to match either the motion direction or orientation of stimuli with the same colour in the memory array. This allowed us to examine the effects of an attention-demanding task performed during maintenance on precision of recall on the concurrent working memory task. Systematic increase in attention load during maintenance resulted in a significant decrease in overall working memory performance. Changes in overall performance were specifically accompanied by an increase in feature misbinding errors: erroneous reporting of nontarget motion or orientation. Thus in trials where attention resources were taxed, participants were more likely to respond with nontarget values rather than simply making random responses. Our findings suggest that resources used during attention-demanding visual or auditory tasks also contribute to maintaining feature-bound representations in visual working memory—but not necessarily other aspects of working memory. PMID:24266343

Attention is required for maintenance of feature binding in visual working memory.

Science.gov (United States)

Zokaei, Nahid; Heider, Maike; Husain, Masud

2014-01-01

Working memory and attention are intimately connected. However, understanding the relationship between the two is challenging. Currently, there is an important controversy about whether objects in working memory are maintained automatically or require resources that are also deployed for visual or auditory attention. Here we investigated the effects of loading attention resources on precision of visual working memory, specifically on correct maintenance of feature-bound objects, using a dual-task paradigm. Participants were presented with a memory array and were asked to remember either direction of motion of random dot kinematograms of different colour, or orientation of coloured bars. During the maintenance period, they performed a secondary visual or auditory task, with varying levels of load. Following a retention period, they adjusted a coloured probe to match either the motion direction or orientation of stimuli with the same colour in the memory array. This allowed us to examine the effects of an attention-demanding task performed during maintenance on precision of recall on the concurrent working memory task. Systematic increase in attention load during maintenance resulted in a significant decrease in overall working memory performance. Changes in overall performance were specifically accompanied by an increase in feature misbinding errors: erroneous reporting of nontarget motion or orientation. Thus in trials where attention resources were taxed, participants were more likely to respond with nontarget values rather than simply making random responses. Our findings suggest that resources used during attention-demanding visual or auditory tasks also contribute to maintaining feature-bound representations in visual working memory-but not necessarily other aspects of working memory.

MO-A-BRB-01: Review of TG-262 Internal Survey of Practices in EMR for External Beam Therapy

International Nuclear Information System (INIS)

Mechalakos, J.

2015-01-01

The process of converting to an electronic chart for radiation therapy can be daunting. It requires a dedicated committee to first research and choose appropriate software, to review the entire documentation policy and flow of the clinic, to convert this system to electronic form or if necessary, redesign the system to more easily conform to the electronic process. Those making the conversion and those who already use electronic charting would benefit from the shared experience of those who have been through the process in the past. Therefore TG262 was convened to provide guidance on electronic charting for external beam radiation therapy and brachytherapy. This course will present the results of an internal survey of task group members on EMR practices in External Beam Radiation Therapy as well as discuss important issues in EMR development and structure for both EBRT and brachytherapy. Learning Objectives: Be familiarized with common practices and pitfalls in development and maintenance of an electronic chart in Radiation Oncology Be familiarized with important issues related to electronic charting in External Beam Radiation Therapy Be familiarized with important issues related to electronic charting in Brachytherapy

Remote maintenance challenges presented in the ITER engineering design

International Nuclear Information System (INIS)

Burgess, T.W.; Herndon, J.N.; Schrock, S.L.; Lousteau, D.C.

1995-01-01

Leading fusion energy research institutions are currently engaged in the Engineering Design Activity for the International Thermonuclear Experimental Reactor (ITER). A tokamak reactor design is evolving which emphasizes high system performance in a minimum overall reactor and building size. The resulting high component density dictates careful attention to ITER remote maintenance considerations in the development of the configuration. The complexity and scale of ITER remote maintenance tasks are well beyond the scope of today's experience and technology. This paper discusses the remote maintenance philosophy, describes the basic configuration as it relates to maintenance, and describes the basic procedures and equipment required. Key enabling technology research and development needs are also addressed

Preventive maintenance program of motorized operated valves (MOV) at Cernavoda NPP

International Nuclear Information System (INIS)

Groza, M.; Moldoveanu, Edy

2001-01-01

This is a Power Point presentation. The following objectives are addressed: A. Determine the target of MOV program; B. Define the strategy for MOV; C. Establish the MOV program execution phases; D. Identification of key parameters; E. Examples. The target of MOV program is to improve the safety by ensuring the adequacy of safety valves and the reliability of safety equipment and, subsequently, to ensure the economic operation of the plant. Consequences of MV malfunction are indicated. The strategy for MOV program development is both general, namely, to define the minimal requirements of preventive /corrective maintenance activities for all MOV's according to design/ manufacture specification and particular, namely to identify MV's specific problems and the need for increasing/decreasing the preventing maintenance tasks or frequency established in 'general' MOV program. Strategy for MOV program development implies: - Establish MOV program applicability; - Develop diagnostic strategy (define key parameters ); - Perform program for engineering review; - Establish program for preventive maintenance; - Revise procedures for operating and maintenance tests; - Dynamic evaluation of MOV. The program execution phases are listed as follows: 1. Perform risk assessment of the MOV's to determine criticality level (program applicability); 2. Collect data to fill in MOV Application Data Sheet; 3. Perform engineering review to determine functional parameters acceptable range and determine key parameters; 4. Analysis for maintenance tasks / frequencies selection and determination of implementing actions (engineer review); 5. Prepare work packages for availability confirmation; 6. Schedule and plan corrective actions or provide input to other programs; 7. Schedule and plan implementing actions in preparation for program field execution; 8. Program field implementation; 9. Program monitoring, evaluation and optimization. The criteria defining the key operational and maintenance

Maintenance concept development for the Compact Ignition Tokamak

International Nuclear Information System (INIS)

Macdonald, D.

1988-01-01

The Compact Ignition Tokamak (CIT), located at the Princeton Plasma Physics Laboratory, will be the next major experimental machine in the US Fusion Program. Its use of deuterium-tritium (D-T) fuel requires the use of remote handling technology to carry out maintenance operations on the machine. These operations consist of removing and repairing such components as diagnostic equipment modules by using remotely operated maintenance equipment. The major equipment being developed for maintenance external to the vacuum vessel includes both bridge-mounted and floor-mounted manipulator systems. Additionally, decontamination (decon) equipment, hot cell repair facilities, and equipment for handling and packaging solid radioactive waste (rad-waste) are being developed. Recent design activities have focused on establishing maintenance system interfaces with the facility design, developing manipulator system requirements, and using mock-ups to support the tokamak configuration design. 3 refs., 8 figs

Maintenance work on CERN mobile phone services

CERN Multimedia

2007-01-01

Maintenance work on the CERN GSM services will be carried out by our mobile operator, Sunrise, from 8.00 p.m. on 25 June to 1 a.m. on 26 June. External calls from CERN mobile phones using the 333 prefix may be disrupted for 30 minutes during this time. Other type of calls, e.g. mobile to mobile or mobile to CERN fixed phones, will not be affected. Should you have any questions regarding this maintenance operation, please contact the switchboard by phone (76111) or e-mail (standard.telephone@cern.ch) Telecom Section IT/CS

Application of reliability centered maintenance to Embalse NPP

International Nuclear Information System (INIS)

Torres, Antonio; Perdomo, Manuel; Fornero, Damian; Corchera, Roberto

2010-01-01

One of the most recent applications of Probabilistic Safety Analysis to Embalse NPP is the Safety Oriented Maintenance Program developed through the Reliability Centered Maintenance (RCM) methodology. Such an application was carried out by a cooperated effort between the staff of nuclear safety department of NPP and experts from Instituto Superior de Tecnologias y Ciencias Aplicadas of Cuba. So far 6 technological systems have been analyzed with important results regarding the optimization of preventive and predictive maintenance program of those systems. Any tasks of RCM were automated via MOSEG code. The results of this study were focused on the elaboration and modification of the Preventive Program, prioritization of stocks, reorientation of predictive techniques and modification in the time parameters of maintenance. (author)

NPP component maintenance and life management in Russia

International Nuclear Information System (INIS)

Tutnov, I.; Lyssakov, V.

2002-01-01

This report represents the conceptual strategies (ideas) on life management programs for nuclear power plants. Use of the optimum programs for NPP's NDE, maintenance service, operation and service life can provide the best economic benefit for the utilities. The paper presents general approaches to life management, maintenance service, and risks of operating and service life of NPPs in Russia. The report offers some optimized ways for the solution of these important tasks

Establishing a predictive maintenance program at the Hanford Site

International Nuclear Information System (INIS)

Winslow, R.W.

1994-05-01

This document contains information about a new Predictive Maintenance Program being developed and implemented at the Hanford Reservation. Details of the document include: background on persons developing the program, history of predictive maintenance, implementation of new program, engineering task analysis, network development and new software, issues to be resolved, benefits expected, and appendix gives information about the symposium from which this paper is based

Comparison of all-remote and personnel access maintenance operations for INTOR

International Nuclear Information System (INIS)

Spampinato, P.T.; Finn, P.A.; Gohar, M.Y.; Stasko, R.R.

1985-01-01

The INTOR reference design was developed to permit limited maintenance operations external to the reactor in a ''hands-on'' mode; all internal operations would be remotely accomplished. The design embodies those requirements for shielding, tritium containment and cleanup, and confinement of contaminated particulate matter to permit personnel access. The cost reflects these requirements, at least first order. The impact of personnel access on the reactor design and its costs are cause to reexamine the maintenance approach on which much of the present configuration is based. The purpose of this study is to compare the benefits and costs associated with personnel access maintenance procedures to those associated with all-remote maintenance procedures and to identify modifications to the baseline design that could enhance maintenance operations

Neuroimaging in aging: brain maintenance [version 1; referees: 2 approved

Directory of Open Access Journals (Sweden)

Lars Nyberg

2017-07-01

Full Text Available Neuroimaging studies of the aging brain provide support that the strongest predictor of preserved memory and cognition in older age is brain maintenance, or relative lack of brain pathology. Evidence for brain maintenance comes from different levels of examination, but up to now relatively few studies have used a longitudinal design. Examining factors that promote brain maintenance in aging is a critical task for the future and may be combined with the use of new techniques for multimodal imaging.

Integrated maintenance program (IMP)

International Nuclear Information System (INIS)

Zemdegs, R.T.; Chout, Q.B.

1998-01-01

the station's maintenance effectiveness and reduce maintenance costs including RCM4, callup overhauls, analysis of equipment and system failure history to name a few. It has become apparent that there is no single D o-All m aintenance strategy. What is needed is an integrated program combining the benefits of a variety of problem-specific strategies. Such a program should address both the short term and long term station requirements. The impact of the Integrated Maintenance Program (IMP) is expected to be high. In the short term, IMP will upgrade the call-up management system to provide accurate classification, effective monitoring and reporting, and develop a documented rationale (PMO) for each Preventive Maintenance task. To the greatest extent possible, IMP will utilize on-condition (predictive) maintenance and result in the elimination of replacement of many obsolete or ineffective preventive maintenance call-ups. The IMP described in this paper, will improve maintenance effectiveness, equipment reliability and have cost benefits to Ontario Hydro. In doing so it will reduce the cost of maintenance and improve system availability and reliability. (author)

Using Modern Methodologies with Maintenance Software

Science.gov (United States)

Streiffert, Barbara A.; Francis, Laurie K.; Smith, Benjamin D.

2014-01-01

Jet Propulsion Laboratory uses multi-mission software produced by the Mission Planning and Sequencing (MPS) team to process, simulate, translate, and package the commands that are sent to a spacecraft. MPS works under the auspices of the Multi-Mission Ground Systems and Services (MGSS). This software consists of nineteen applications that are in maintenance. The MPS software is classified as either class B (mission critical) or class C (mission important). The scheduling of tasks is difficult because mission needs must be addressed prior to performing any other tasks and those needs often spring up unexpectedly. Keeping track of the tasks that everyone is working on is also difficult because each person is working on a different software component. Recently the group adopted the Scrum methodology for planning and scheduling tasks. Scrum is one of the newer methodologies typically used in agile development. In the Scrum development environment, teams pick their tasks that are to be completed within a sprint based on priority. The team specifies the sprint length usually a month or less. Scrum is typically used for new development of one application. In the Scrum methodology there is a scrum master who is a facilitator who tries to make sure that everything moves smoothly, a product owner who represents the user(s) of the software and the team. MPS is not the traditional environment for the Scrum methodology. MPS has many software applications in maintenance, team members who are working on disparate applications, many users, and is interruptible based on mission needs, issues and requirements. In order to use scrum, the methodology needed adaptation to MPS. Scrum was chosen because it is adaptable. This paper is about the development of the process for using scrum, a new development methodology, with a team that works on disparate interruptible tasks on multiple software applications.

Preventive maintenance basis: Volume 16 -- Power operated relief valves, solenoid actuated. Final report

International Nuclear Information System (INIS)

Worledge, D.; Hinchcliffe, G.

1997-07-01

US nuclear plants are implementing preventive maintenance (PM) tasks with little documented basis beyond fundamental vendor information to support the tasks or their intervals. The Preventive Maintenance Basis project provides utilities with the technical basis for PM tasks and task intervals associated with 40 specific components such as valves, electric motors, pumps, and HVAC equipment. This report provides an overview of the PM Basis project and describes use of the PM Basis database. This volume 16 of the report provides a program of PM tasks suitable for application to power operated relief valves (PORV's) that are solenoid actuated. The PM tasks that are recommended provide a cost-effective way to intercept the causes and mechanisms that lead to degradation and failure. They can be used, in conjunction with material from other sources, to develop a complete PM program or to improve an existing program. Users of this information will be utility managers, supervisors, craft technicians, and training instructors responsible for developing, optimizing, or fine-tuning PM programs

[A comparative study of maintenance services using the data-mining technique].

Science.gov (United States)

Cruz, Antonio M; Aguilera-Huertas, Wilmer A; Días-Mora, Darío A

2009-08-01

The main goal in this research was comparing two hospitals' maintenance service quality. One of them had a contract service; the other one had an in-house maintenance service. The authors followed the next stages when conducting this research: domain understanding, data characterisation and sample reduction, insight characterisation and building the TAT predictor. Multiple linear regression and clustering techniques were used for improving the efficiency of corrective maintenance tasks in a clinical engineering department (CED). The indicator being studied was turnaround time (TAT). The institution having an in-house maintenance service had better quality indicators than the contract maintenance service. There was lineal dependence between availability and service productivity.

Multiple Learning Strategies Project. Building Maintenance & Engineering. Low Reader. [Vol. 1.

Science.gov (United States)

Smith, Dwight; And Others

This instructional package is one of two designed for low reader students (those reading at a 3-6 grade level) in the vocational area of building maintenance and engineering. The forty-six learning modules are organized into three units: floor care; general maintenance tasks; and restrooms. Each module includes these elements: a performance…

Optimization of radiation protection of cell maintenance of radiopharmaceutical production

International Nuclear Information System (INIS)

Machado, Jessica S.; Gerulis, Eduardo; Todo, Alberto S.; Rodrigues Junior, Orlando

2011-01-01

This paper performs a study of maintenance tasks realized in production cells to suggest improvements related to the occupational doses based on the optimization principle of the radioprotection. A data survey has been realized of the doses received by the workers during the maintenance. The average values of effective doses are lower than the limits established in the regulations, however can be optimized

Dental hygiene student experiences in external placements in Australia.

Science.gov (United States)

Taylor, Jane A; Hayes, Melanie J; Wallace, Linda

2012-05-01

While placements in external locations are being increasingly used in dental education globally, few studies have explored the student learning experience at such placements. The purpose of this study was to investigate student experiences while on external placement in a baccalaureate dental hygiene program. A self-reporting questionnaire was distributed to final-year dental hygiene students (n=77) at the University of Newcastle, Australia, in 2010. The questionnaire included questions regarding the type of placement, experiences offered, supervision, resources available, and lasting impressions. Responding students were generally positive about their external placement experience and indicated that the majority of facilities provided them with the opportunity to provide direct patient care and perform clinical tasks typical of a practicing hygienist. However, there was a statistically significant difference in their opinions about discipline-focused and community placements. Students indicated that their external placement experience provided opportunities to learn more about time and patient management, including hands-on experience with specific clinical tasks. Ongoing evaluations are necessary to ensure that external placements meet both student needs and intended learning outcomes within dental hygiene programs.

Operations and maintenance plans for the TFTR

International Nuclear Information System (INIS)

Allen, H.L.; Fedor, B.J.

1978-01-01

Princeton University Plasma Physics Laboratory (PPPL) is constructing a Tokamak Fusion Test Reactor (TFTR) scheduled to begin operation for fusion research experiments in late 1981, first with hydrogen and deuterium plasmas and later, in the second phase, using tritium for high power fusion studies. This latter mode will introduce considerable complexity to operation and maintenance of the TFTR in terms of meeting requirements for tritium handling, adequate radiation shielding, and corrective and preventive maintenance procedures. In this paper we discuss plans for the installation and preoperational testing of the major subsystems of TFTR, proposed start-up and operating scenarios for the device and the system of operational control. In addition, the TFTR Maintenance Plan and related procedures for specific major maintenance tasks are described, including the use of remote handling equipment and remote manipulators. Each of these topics is addressed in terms of the current status of planning and development

ITER assembly and maintenance

International Nuclear Information System (INIS)

Honda, T.; Davis, F.; Lousteau, D.

1991-01-01

This document is intended to describe the work conducted by the ITER Assembly and Maintenance (A and M) Design Unit and the supporting home teams during the ITER Conceptual Design Activities, carried out from 1988 through 1990. Its content consists of two main sections, i.e., Chapter III, which describes the identified tasks to be performed by the A and M system and a general description of the required equipment; and Chapter IV, which provides a more detailed description of the equipment proposed to perform the assigned tasks. A two-stage R and D program is now planned, i.e., (1) a prototype equipment functional tests using full scale mock-ups and (2) a full scale integration demonstration test facility with real components (vacuum vessel with ports, blanket modules, divertor modules, armor tiles, etc.). Crucial in-vessel and ex-vessel operations and the associated remote handling equipment, including handling of divertor plates and blanket modules will be demonstrated in the first phase, whereby the database needed to proceed with the engineering phase will be acquired. The second phase will demonstrate the ability of the overall system to execute the required maintenance procedures and evaluate the performance of the prototype equipment

An Abstraction Hierarchy based mobile PC display design in NPP maintenance considering the level of expertise

International Nuclear Information System (INIS)

Yim, Ho Bin; Kim, In; Seong, Poong Hyun

2011-01-01

Research highlights: → Six levels of Abstraction Hierarchy based information for maintenance were proposed. → Errors and workload with AH based information display were reduced for LL subjects. → Design concerns discovered can be applied to practical use of mobile maintenance aids. - Abstract: Recently, the importance of effective maintenance in nuclear power plants (NPPs) has been emphasized and research into effective maintenance by adopting mobile maintenance aids (MMAs) have been attempted. For improved and effective use of an MMA display design method based on the hierarchy is proposed and its design considerations are discussed in this study. Six levels of hierarchy are proposed in this paper to classify the maintenance information. By classifying and organizing maintenance information using the hierarchy, maintenance information can be used effectively by users with either high or low levels of expertise. When information classification has been finished, the information for MMA design is selected and designed. With the considerations of MMA design analysis and guidelines, a hierarchy-based MMA is designed for the maintenance tasks. An experiment is conducted using the hierarchy-based MMA in order to estimate the effectiveness of the proposed method for the maintenance tasks and to identify design considerations to enhance the proposed MMAs. The result indicated that a hierarchy-based manual was more effective than a conventional manual in terms of task completion time and number of errors. The workload for the hierarchy-based manual was estimated less than the conventional manual for subjects with low level of expertise. As the level of expertise increases, subjects tended to follow more abstract information while the number of navigations decreased. It is believed that when mobile devices become pervasive in NPP maintenance fields, the hierarchy model applied MMAs can be used as an effective maintenance supporting tool.

The operational challenge of remote maintenance

International Nuclear Information System (INIS)

Forsythe, L.

2015-01-01

Full text of publication follows. With the declining supply of fossil fuels that are used in power stations today, and the ongoing concern over climate change, nuclear fusion is one of the most promising options for generating large amounts of carbon-free energy in the future. Fuel supplies for fusion will be available for millions of years, with 1 kg of fusion fuel providing the same amount of energy as 10 thousand tonnes of fossil fuel. Unlike conventional fission reactors, the radioactive waste produced from fusion is short-lived, and will be safe to dispose of conventionally within 100 years. Although fusion has the huge advantage of being a carbon free energy source, there are complexities when it comes to maintaining the machine. Due to the nature of the fusion reaction, the components within the area of the reactor vacuum vessel become radioactive, which requires maintenance and modifications to be conducted remotely to protect human operators. Remote maintenance is the use of manipulators to carry out tasks in challenging or hostile environments, which would otherwise cause harm to humans. Remote handling slave manipulators do the work of a human by mimicking the movements from a master robotic manipulator that is controlled by a human operator. This means that remote handling can be used in many other areas other too, such as space; fission power plants; sub-sea; and nuclear material handling or in adverse environments such as: low or high temperature; chemically contaminated; combustible and low oxygen environments. Remote maintenance requires specialist engineers to take into consideration many aspects normally taken for granted when carrying out a task manually. Constraints such as the space around us; viewing and lighting; the human body's dexterity and flexibility; the weight and centre of gravity of tools and components, and how we securely grip and handle them; and access to fixings and fastenings. All these are factors that require careful

Integrated maintenance management model in the printing industry

Directory of Open Access Journals (Sweden)

Csaba Horváth

2010-09-01

Full Text Available Rapid technological and economic changes are setting radically new task for maintenance divisions of printingworks. In this dissertation the author provides a summary on the possible approaches for the adoption to the newrequirements. He formulates his situation analysis based on an exhaustive questionnaire survey, and points out thecurrents of changes and challenges caused by the expected developments in the maintenance field of the printingindustry.Based on the possible answers on these challenges, the Author has compiled a - yet missing - maintenance managementmodel that encompasses the maintenance specialties of the industry, as well as the professional heritage andthe latest scientific accomplishments in the discipline of maintenance.The model is based on the widely accepted quality focused maintenance approach, that is supplemented by theAuthor with four new aspects - 1 reliability-focused culture, 2 quality management system, 3 employment ofexternal service provides, 4 maintenance characteristics specific to printing machinery - determining their effectsand integrating them into one single system.In order to construct the model, the Author develops specific solutions that can be seen as own scientific achievementson the specification of maintenance characteristics of printing machinery; on the efficiency improving applicationsof quality management systems, modern knowledge management and reliability focused corporate culture;and on the implementation of a maintenance information system.

Brain Activation during Associative Short-Term Memory Maintenance is Not Predictive for Subsequent Retrieval

Directory of Open Access Journals (Sweden)

Heiko eBergmann

2015-09-01

Full Text Available Performance on working memory (WM tasks may partially be supported by long-term memory (LTM processing. Hence, brain activation recently being implicated in WM may actually have been driven by (incidental LTM formation. We examined which brain regions actually support successful WM processing, rather than being confounded by LTM processes, during the maintenance and probe phase of a WM task. We administered a four-pair (faces and houses associative delayed-match-to-sample (WM task using event-related fMRI and a subsequent associative recognition LTM task, using the same stimuli. This enabled us to analyze subsequent memory effects for both the WM and the LTM test by contrasting correctly recognized pairs with incorrect pairs for either task. Critically, with respect to the subsequent WM effect, we computed this analysis exclusively for trials that were forgotten in the subsequent LTM recognition task. Hence, brain activity associated with successful WM processing was less likely to be confounded by incidental LTM formation. The subsequent LTM effect, in contrast, was analyzed exclusively for pairs that previously had been correctly recognized in the WM task, disclosing brain regions involved in successful LTM formation after successful WM processing. Results for the subsequent WM effect showed no significantly activated brain areas for WM maintenance, possibly due to an insensitivity of fMRI to mechanisms underlying active WM maintenance. In contrast, a correct decision at WM probe was linked to activation in the retrieval success network (anterior and posterior midline brain structures. The subsequent LTM analyses revealed greater activation in left dorsolateral prefrontal cortex and posterior parietal cortex in the early phase of the maintenance stage. No supra-threshold activation was found during the WM probe. Together, we obtained clearer insights in which brain regions support successful WM and LTM without the potential confound of the

Brain activation during associative short-term memory maintenance is not predictive for subsequent retrieval.

Science.gov (United States)

Bergmann, Heiko C; Daselaar, Sander M; Beul, Sarah F; Rijpkema, Mark; Fernández, Guillén; Kessels, Roy P C

2015-01-01

Performance on working memory (WM) tasks may partially be supported by long-term memory (LTM) processing. Hence, brain activation recently being implicated in WM may actually have been driven by (incidental) LTM formation. We examined which brain regions actually support successful WM processing, rather than being confounded by LTM processes, during the maintenance and probe phase of a WM task. We administered a four-pair (faces and houses) associative delayed-match-to-sample (WM) task using event-related functional MRI (fMRI) and a subsequent associative recognition LTM task, using the same stimuli. This enabled us to analyze subsequent memory effects for both the WM and the LTM test by contrasting correctly recognized pairs with incorrect pairs for either task. Critically, with respect to the subsequent WM effect, we computed this analysis exclusively for trials that were forgotten in the subsequent LTM recognition task. Hence, brain activity associated with successful WM processing was less likely to be confounded by incidental LTM formation. The subsequent LTM effect, in contrast, was analyzed exclusively for pairs that previously had been correctly recognized in the WM task, disclosing brain regions involved in successful LTM formation after successful WM processing. Results for the subsequent WM effect showed no significantly activated brain areas for WM maintenance, possibly due to an insensitivity of fMRI to mechanisms underlying active WM maintenance. In contrast, a correct decision at WM probe was linked to activation in the "retrieval success network" (anterior and posterior midline brain structures). The subsequent LTM analyses revealed greater activation in left dorsolateral prefrontal cortex and posterior parietal cortex in the early phase of the maintenance stage. No supra-threshold activation was found during the WM probe. Together, we obtained clearer insights in which brain regions support successful WM and LTM without the potential confound of

On-line maintenance at Cofrentes NPP

International Nuclear Information System (INIS)

Roldan Vilches, J.; Moreno Matarranz, M. A.; Hermana Mendioroz, I.

1998-01-01

Cofrentes NPP has begun in 1997 activities related to At Power Preventive Maintenance over trains or systems which lead to a voluntary entry in a Limitative Condition of Operation (LCO) of the Technical Specifications. From others benefits, this program ha improved the risk management and the staff's knowledge over the functions and safety implications of the different systems, the better exploit of the resources, the co-ordination of the different organisations involved (Maintenance an Operation) and the reductions of works during shutdowns. Previous to each work, a feasibility study analyzes qualitative and quantitative (PSA), using the Risk Monitor, the implications on safety of all the tasks, assuring that the global safety of the Plant is always maintained. Tech. Spec. are analyzed in detail and also are analyzed situations of simultaneous unavailabilities of systems which could lead to a high risk situation. Two different risk controls are defined (punctual and accumulated) to assure that high risk situations will not be given. Finally, historical risk profile is analyzed to assure that the accumulated risk increase is not significant. Risk Monitor helps staff in the schedule and follow-up of the activities of On-Line Maintenance. Each one of the tasks are deeply planned and harshly analyzed and are carried out by high qualified workers. By the moment, this program is running with fully satisfaction on the Plant. (Author)

Experiences on implementation of on-the-job training programmes for maintenance personnel in Asco and Vandellos II NPP

International Nuclear Information System (INIS)

Gonzalez Anez, F.

2002-01-01

This paper presents a process and methodology for definition and implementation of On-Job-Training Programmes (OJTP) for new maintenance personnel in Asco and Vandellos II. The content of these OJTP has been defined for each maintenance job position. A simplified task analysis was carried out to specify common and specific training. Generally, the specific maintenance training programs includes training modules in classroom and workshop environment on (1) maintenance of components and (2) maintenance fundamentals of mechanical, electrical and instrumentation. This specific training has been finally completed with a OJT programme based on the execution, observation or/and discussion about the main maintenance activities under entitled worker supervision. Each lesson, task or activity is defined in a format where the training objective, milestones and deliverables are specified. The list of activities makes up the OJTP. It is based on applicable plant procedures and maintenance instruction to each job position. Several participants or actors have been defined to implement the OJTP: co-ordinator of the process, tutors for each OJT task, line maintenance manager and trainee. Co-ordinator is the link among all actors. He knows the OJTP scope and plans the training activities according to the line maintenance manager. Co-ordinator carries out a tracking process, informs to training and maintenance managers about the progress in the programme, elaborates the progress and final reports and keeps training records. Tutors, usually entitled workers in the job position, transfer the knowledge to the trainee and discuss, review and assess the trainee's performance. Trainee carries out the scheduled tasks, keeps records of work done, prepares deliverables and informs about his activities to the Co-ordinator. The OJT programme for each new maintenance worker starts with a launching meeting with all involved actors. The goals of this meeting are to explain the OJTP scope and

Multiple Learning Strategies Project. Building Maintenance & Engineering. Educable Mentally Impaired. [Vol. 2.

Science.gov (United States)

Constantini, Debra; And Others

This instructional package is one of three designed for educable mentally impaired students in the vocational area of building maintenance and engineering. The thirty-four learning modules are organized into six units: general maintenance tasks; restrooms; chalkboards; carpet care; office cleaning; and grounds. Each module includes these elements:…

A new mobile application for maintenance tasks in photovoltaic installations by using GPS data

International Nuclear Information System (INIS)

Fernández-Pacheco, D.G.; Molina-Martínez, J.M.; Ruiz-Canales, A.; Jiménez, M.

2012-01-01

Highlights: ► Portable and easy-to-use solution to detect possible failures at a PV installation. ► Calculation of solar and photovoltaic parameters by using a mobile device with GPS. ► No software which confers this utility to a mobile device can be found in the market. - Abstract: The application of the Information and Communication Technologies (ICTs) to the photovoltaic (PV) energy sector has increased notably in the last years. This paper presents a new mobile software application for maintenance tasks in PV installations by determining the PV output power of the system, the daily energy production, the clear-sky global solar radiation and other parameters associated with solar position from Global Position Data in handheld devices endowed with Android or Windows Mobile operating systems. The calculation of these parameters permits a technician to know if the PV plant is working properly, since the difference between the PV output power supplied by the installation in a clear-sky day for a determined hourly period and the values estimated by the application should be minimal. In case of fixed installations, the application also permits to determine if the PV module support structures of the installation are correctly oriented. Some comparisons between data supplied by four real PV installations and data calculated by the proposed application were performed for evaluation purposes.

The Effect of Fatigued External Rotator Muscles of the Shoulder on the Shoulder Position Sense

Directory of Open Access Journals (Sweden)

Naoya Iida

2011-10-01

Full Text Available This study aimed to investigate the effect of fatigue in shoulder external rotator muscles on position sense of shoulder abduction, internal rotation, and external rotation. The study included 10 healthy subjects. Shoulder position sense was measured before and after a fatigue task involving shoulder external rotator muscles. The fatigue task was performed using an isokinetic machine. To confirm the muscle fatigue, electromyography (EMG was recorded, and an integrated EMG and median power frequency (MDF during 3 sec performed target torque were calculated. After the fatigue task, the MDF of the infraspinatus muscle significantly decreased. This indicates that the infraspinatus muscle was involved in the fatigue task. In addition, the shoulder position sense of internal and external rotation significantly decreased after the fatigue task. These results suggest that the fatigue reduced the accuracy of sensory input from muscle spindles. However, no significant difference was observed in shoulder position sense of abduction before and after the fatigue task. This may be due to the fact that infraspinatus muscle did not act as prime movers in shoulder abduction. These results suggest that muscle fatigue decreased position sense during movements in which the affected muscles acted as prime movers.

Multiple Learning Strategies Project. Building Maintenance & Engineering. Educable Mentally Impaired. [Vol. 1.

Science.gov (United States)

Smith, Dwight; And Others

This instructional package is one of three designed for educable mentally impaired students in the vocational area of building maintenance and engineering. The thirty learning modules are organized into two units: floor care and general maintenance tasks. Each module includes these elements: a performance objective page which tells the student…

A study on mobile PC display design in NPP maintenance considering the level of expertise

International Nuclear Information System (INIS)

Kim, In

2010-02-01

Recently, the importance of effective maintenance in nuclear power plants (NPPs) has been emphasized and research into effective maintenance by adopting mobile maintenance aids (MMAs) have been attempted. MMAs are currently used during operation and maintenance in NPPs, but no method that considers the limitations of mobile devices has been proposed. For improved and effective use, an MMA display design method based on abstraction hierarchy (AH) is proposed and its design considerations are discussed in this study. Six levels of abstraction hierarchy are proposed in this paper to classify the maintenance information. By classifying and organizing maintenance information using AH, maintenance information can be used effectively by users either high or low levels of expertise. When information classification has been finished, the information requirements and relationships for MMA design is extracted from the analysis of the AH result. Representative human-machine interface (HMI) guidelines issued by the US NRC, which are generally used in NPPs, are applied. With the considerations of MMA design analysis and practical guidelines, AH-based MMA is designed for maintenance tasks. An experiment is conducted using the AH-based MMA in order to estimate the effectiveness of the proposed method for maintenance tasks and to identify design considerations to enhance the proposed MMAs. The result indicated that an AH-based manual was more effective than a conventional manual in terms of task completion time and number of errors. The workload for the AH-based manual was estimated to be less than the conventional manual for low levels of expertise. However, a conventional manual was more comprehensive than the proposed manual and the steps contained in the maintenance manual were easier to remember. As the level of expertise increases, subjects tended to follow more abstract information while the number of navigations decreased. It is believed that when mobile devices become

Design of equipment safety & reliability for an aseptic liquid food packaging line through maintenance engineering

OpenAIRE

Riccetti, Sauro

2011-01-01

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. The organisation of maintenance, in the Aseptic Liquid Food (ALF) industry, represents an important management task that enables a company to pursue higher manufacturing effectiveness and improved market share. This research is concerned with the process to design and implement maintenance tasks. These two complementary processes (design and implementation) have been thought and designed to a...

Experience based reliability centered maintenance

International Nuclear Information System (INIS)

Haenninen, S.; Laakso, K.

1993-03-01

The systematic analysis and documentation of operating experiences should be included in a living NPP life management program. Failure mode and effects and maintenance effects analyses are suitable methods for analysis of the failure and corrective maintenance experiences of equipment. Combined use of the information on occurred functional failures and the decision tree logic of the reliability centered maintenance identifies applicable and effective preventive maintenance tasks of equipment in an old plant. In this study the electrical motor drives of closing and isolation valves (MOV) of TVO and Loviisa nuclear power plants were selected to serve as pilot study objects. The study was limited to valve drives having actuators manufactured by AUMA in Germany. The fault and maintenance history of MOVs from 1981 up to and including October 1991 in different safety and process systems at TVO 1 and 2 nuclear power units was at first analyzed in a systematic way. The scope of the components studied was 81 MOVs in safety-related systems and 127 other MOVs per each TVO unit. In the case of the Loviisa plant, the observation period was limited to three years, i.e. from February 1989 up to February 1992. The scope of the Loviisa 1 and 2 components studied was 44 respectively 95 MOVs. (25 refs., 22 figs., 8 tabs.)

Development and maintenance of product configuration systems: Requirements for a documentation tool

DEFF Research Database (Denmark)

Hvam, Lars; Christensen, Simon Pape; Jensen, Klaes Ladeby

2005-01-01

by letting a documentation tool handle trivial time consuming tasks (notification on change, consistency check etc.), as a computer often handles these tasks in a better way. Thus, a serious bottleneck in the maintenance of configuration systems can be eliminated by applying Information System (IS...

Evaluation of artillery equipment maintenance support capability based on grey clustering

Science.gov (United States)

Zhai, Mei-jie; Gao, Peng

2017-12-01

This paper, the theory and method of evaluating the capability of equipment maintenance support in China and abroad are studied, from the point of view of the combat task of artillery troops and the strategic attachment in the future military struggle. This paper establishes the framework of the evaluation Index system of the equipment maintenance support capability of the artillery units, and applies the grey clustering method to the evaluation of the equipment maintenance support capability of the artillery units, and finally evaluates the equipment maintenance and support capability of the artillery brigade as an example, and analyzes the evaluation results. This paper finds out the outstanding problems existing in the maintenance and support of military equipment, and puts forward some constructive suggestions, in order to improve the status of military equipment maintenance and support and improve the level of future equipment maintenance.

Computerized management of plant intervention tasks

International Nuclear Information System (INIS)

Remacle, J.; Quoidbach, G.

1993-01-01

The concept of 'computerized management' of plant intervention tasks was developed by TRACTEBEL in 1983 for the Belgian power plants of ELECTRABEL. The main objective of the 'Computerized Management of Plant Intervention Tasks' is to help the staff of a nuclear or a conventional power plant in planning, organizing, and carrying out any (preventive or corrective) maintenance task. It consists of a group of interconnected functional modules acting on a unique and homogeneous data base. A short description of 3 modules is given, i.e., the 'User' Module, the 'Equipment' Module and the 'Periodic Procedure' Module. (Z.S.)

Designer's guidebook for first wall/blanket/shield assembly, maintenance, and repair

International Nuclear Information System (INIS)

1983-01-01

This is the initial issue of the guidebook. Since a guidebook of this type must incorporate information concerning a wide range of subjects, much additional data will eventually be included. The guidebook will document, in summary and easily referenceable form, data, designs, design concepts, design guidelines and background information useful to the FWBS and to the Maintenance System designer. In providing guidelines for the AMR of the FWBS, the guidebook must, of necessity, include guidelines for all aspects of maintenance associated with the FWBS. These include most maintenance operations within the reactor room necessary to gain access, identify faults, and handle equipment related to FWBS maintenance. In addition, the guidelines include those required to define facility requirements for handling and repair of FWBS and related reactor components external to the reactor room. Particular emphasis is given to remote maintenance design and operations

Human Error Probability Assessment During Maintenance Activities of Marine Systems

Directory of Open Access Journals (Sweden)

Rabiul Islam

2018-03-01

Full Text Available Background: Maintenance operations on-board ships are highly demanding. Maintenance operations are intensive activities requiring high man–machine interactions in challenging and evolving conditions. The evolving conditions are weather conditions, workplace temperature, ship motion, noise and vibration, and workload and stress. For example, extreme weather condition affects seafarers' performance, increasing the chances of error, and, consequently, can cause injuries or fatalities to personnel. An effective human error probability model is required to better manage maintenance on-board ships. The developed model would assist in developing and maintaining effective risk management protocols. Thus, the objective of this study is to develop a human error probability model considering various internal and external factors affecting seafarers' performance. Methods: The human error probability model is developed using probability theory applied to Bayesian network. The model is tested using the data received through the developed questionnaire survey of >200 experienced seafarers with >5 years of experience. The model developed in this study is used to find out the reliability of human performance on particular maintenance activities. Results: The developed methodology is tested on the maintenance of marine engine's cooling water pump for engine department and anchor windlass for deck department. In the considered case studies, human error probabilities are estimated in various scenarios and the results are compared between the scenarios and the different seafarer categories. The results of the case studies for both departments are also compared. Conclusion: The developed model is effective in assessing human error probabilities. These probabilities would get dynamically updated as and when new information is available on changes in either internal (i.e., training, experience, and fatigue or external (i.e., environmental and operational conditions

Determination of Pareto frontier in multi-objective maintenance optimization

International Nuclear Information System (INIS)

Certa, Antonella; Galante, Giacomo; Lupo, Toni; Passannanti, Gianfranco

2011-01-01

The objective of a maintenance policy generally is the global maintenance cost minimization that involves not only the direct costs for both the maintenance actions and the spare parts, but also those ones due to the system stop for preventive maintenance and the downtime for failure. For some operating systems, the failure event can be dangerous so that they are asked to operate assuring a very high reliability level between two consecutive fixed stops. The present paper attempts to individuate the set of elements on which performing maintenance actions so that the system can assure the required reliability level until the next fixed stop for maintenance, minimizing both the global maintenance cost and the total maintenance time. In order to solve the previous constrained multi-objective optimization problem, an effective approach is proposed to obtain the best solutions (that is the Pareto optimal frontier) among which the decision maker will choose the more suitable one. As well known, describing the whole Pareto optimal frontier generally is a troublesome task. The paper proposes an algorithm able to rapidly overcome this problem and its effectiveness is shown by an application to a case study regarding a complex series-parallel system.

Dynamical signatures of isometric force control as a function of age, expertise, and task constraints.

Science.gov (United States)

Vieluf, Solveig; Sleimen-Malkoun, Rita; Voelcker-Rehage, Claudia; Jirsa, Viktor; Reuter, Eva-Maria; Godde, Ben; Temprado, Jean-Jacques; Huys, Raoul

2017-07-01

From the conceptual and methodological framework of the dynamical systems approach, force control results from complex interactions of various subsystems yielding observable behavioral fluctuations, which comprise both deterministic (predictable) and stochastic (noise-like) dynamical components. Here, we investigated these components contributing to the observed variability in force control in groups of participants differing in age and expertise level. To this aim, young (18-25 yr) as well as late middle-aged (55-65 yr) novices and experts (precision mechanics) performed a force maintenance and a force modulation task. Results showed that whereas the amplitude of force variability did not differ across groups in the maintenance tasks, in the modulation task it was higher for late middle-aged novices than for experts and higher for both these groups than for young participants. Within both tasks and for all groups, stochastic fluctuations were lowest where the deterministic influence was smallest. However, although all groups showed similar dynamics underlying force control in the maintenance task, a group effect was found for deterministic and stochastic fluctuations in the modulation task. The latter findings imply that both components were involved in the observed group differences in the variability of force fluctuations in the modulation task. These findings suggest that between groups the general characteristics of the dynamics do not differ in either task and that force control is more affected by age than by expertise. However, expertise seems to counteract some of the age effects. NEW & NOTEWORTHY Stochastic and deterministic dynamical components contribute to force production. Dynamical signatures differ between force maintenance and cyclic force modulation tasks but hardly between age and expertise groups. Differences in both stochastic and deterministic components are associated with group differences in behavioral variability, and observed behavioral

Proactive maintenance initiatives at Argonne National Laboratory-West

International Nuclear Information System (INIS)

Duckwitz, N.R.; Duncan, L.W.; Whipple, J.J.

1995-01-01

In the late 1980's, ANL-W Management foresaw a need to provide dedicated technical support for maintenance supervisors. Maintenance supervisors were facing increased challenges to ensure all environmental, safety, and waste management regulations were followed in daily maintenance activities. This increased burden was diverting supervisory time away from on-the-job supervision. Supervisors were finding less time for their ''mentor'' roles to ensure maintenance focused on finding and correcting root causes. Additionally the traditional maintenance organization could not keep up with the explosion in predictive maintenance technologies. As a result, engineers were tasked to provide direct technical support to the maintenance organization. Today the maintenance technical support group consists of two mechanical engineers, two electrical engineers and an I ampersand C engineer. The group provides a readily available, quick response resource for crafts people and their supervisors. They can and frequently do ask the support group for help to determine the root cause and to effect permanent fixes. Crafts and engineers work together informally to make an effective maintenance team. In addition to day-to-day problem solving, the technical support group has established several maintenance improvement programs for the site. This includes vibration analysis of rotating machinery, testing of fuel for emergency diesel generators, improving techniques for testing of high efficiency particulate air (HEPA) filters, and capacity testing of UPS and emergency diesel starting batteries. These programs have increased equipment reliability, reduced conventional routine maintenance, reduced unexpected maintenance, and improved testing accuracy. This paper will discuss the interaction of the technical support group within the maintenance department. Additionally the maintenance improvement programs will be presented along with actual cases encountered, the resolutions and lessons learned

A study on an autonomous pipeline maintenance robot, 5

International Nuclear Information System (INIS)

Fukuda, Toshio; Hosokai, Hidemi; Otsuka, Masashi.

1989-01-01

The path planning is very important for the pipeline maintenance robot because there are many obstacles on pipeline such as flanges and T-joints and others, and because pipelines are constructed as a connected network in a very complicated way. Furthermore the maintenance robot Mark III previously reported has the ability to transit from one pipe to another the path planner should consider. The expert system especially aimed for path planning, named PPES (Path Planning Expert System), is described in this paper. A human-operator has only to give some tasks to this system. This system automatically replies with the optimal path, which is based on the calculation of the task levels and list of some control commands. Task level is a criterion to determine one optimal path. It consists of the difference of potential energies, the static joint torques, velocity of the robot, step numbers of the grippers' or body's movement, which the robot requires. This system also has graphic illustrations, so that the operator can easily check and understand the plant map and the result of the path planning. (author)

Task relevance modulates the cortical representation of feature conjunctions in the target template.

Science.gov (United States)

Reeder, Reshanne R; Hanke, Michael; Pollmann, Stefan

2017-07-03

Little is known about the cortical regions involved in representing task-related content in preparation for visual task performance. Here we used representational similarity analysis (RSA) to investigate the BOLD response pattern similarity between task relevant and task irrelevant feature dimensions during conjunction viewing and target template maintenance prior to visual search. Subjects were cued to search for a spatial frequency (SF) or orientation of a Gabor grating and we measured BOLD signal during cue and delay periods before the onset of a search display. RSA of delay period activity revealed that widespread regions in frontal, posterior parietal, and occipitotemporal cortices showed general representational differences between task relevant and task irrelevant dimensions (e.g., orientation vs. SF). In contrast, RSA of cue period activity revealed sensory-related representational differences between cue images (regardless of task) at the occipital pole and additionally in the frontal pole. Our data show that task and sensory information are represented differently during viewing and during target template maintenance, and that task relevance modulates the representation of visual information across the cortex.

Probabilistic safety assessment support for the maintenance rule at Duke Power Company

International Nuclear Information System (INIS)

Brewer, H. Duncan; Canady, Ken S.

1999-01-01

The Nuclear Regulatory Commission (NRC) published the Maintenance Rule on July 10, 1991 with an implementation date of July 10, 1996 . Maintenance rule implementation at the Duke Power Company has used probabilistic safety assessment (PSA) insights to help focus the monitoring of structures, systems and components (SSC) performance and to ensure that maintenance is effectively performed. This paper describes how the probabilistic risk assessment (PRA) group at the Duke Power Company provides support for the maintenance rule by performing the following tasks: (1) providing a member of the expert panel; (2) determining the risk-significant SSCs; (3) establishing SSC performance criteria for availability and reliability; (4) evaluating past performance and its impact on core damage risk as part of the periodic assessment; (5) providing input to the PRA matrix; (6) providing risk analyses of combinations of SSCs out of service; (7) providing support for the SENTINEL program; and (8) providing support for PSA training. These tasks are not simply tied to the initial implementation of the rule. The maintenance rule must be kept consistent with the current design and operation of the plant. This will require that the PRA models and the many PSA calculations performed to support the maintenance rule are kept up-to-date. Therefore, support of the maintenance rule will be one of the primary roles of the PSA group for the remainder of the life of the plant

Ex-vessel remote maintenance for the Compact Ignition Tokamak

International Nuclear Information System (INIS)

Spampinato, P.T.; Macdonald, D.

1987-01-01

The use of deuterium-tritium (D-T) fuel for operation of the Compact Ignition Tokamak (CIT) requires the use of remote handling technology to carry out maintenance operations on the machine. These operations consist in removing and repairing such components as diagnostic modules by using remotely operated maintenance equipment. The major equipment being developed for maintenance external to the plasma chamber includes a bridge-mounted manipulator system for test cell operations, decontamination (decon) equipment, hot cell equipment, and solid-radiation-waste-handling equipment. Wherever possible, the project will use commercially available equipment. Several areas of the maintenance system design were addressed in fiscal year (FY) 1987, including conceptual designs of manipulator systems, the start of a remote equipment research and development (RandD) program, and definition of the hot cell, decon, and equipment repair facility requirements. R and D work included preliminary demonstrations of remote handling operations on full-size, partial mock-ups of the CIT machine at the Oak Ridge National Laboratory (ORNL) Remote Operations and Maintenance Development (ROMD) Facility. 1 ref., 6 figs

Maintenance modeling and optimization integrating human and material resources

International Nuclear Information System (INIS)

Martorell, S.; Villamizar, M.; Carlos, S.; Sanchez, A.

2010-01-01

Maintenance planning is a subject of concern to many industrial sectors as plant safety and business depend on it. Traditionally, the maintenance planning is formulated in terms of a multi-objective optimization (MOP) problem where reliability, availability, maintainability and cost (RAM+C) act as decision criteria and maintenance strategies (i.e. maintenance tasks intervals) act as the only decision variables. However the appropriate development of each maintenance strategy depends not only on the maintenance intervals but also on the resources (human and material) available to implement such strategies. Thus, the effect of the necessary resources on RAM+C needs to be modeled and accounted for in formulating the MOP affecting the set of objectives and constraints. In this paper RAM+C models to explicitly address the effect of human resources and material resources (spare parts) on RAM+C criteria are proposed. This extended model allows accounting for explicitly how the above decision criteria depends on the basic model parameters representing the type of strategies, maintenance intervals, durations, human resources and material resources. Finally, an application case is performed to optimize the maintenance plan of a motor-driven pump equipment considering as decision variables maintenance and test intervals and human and material resources.

Maintenance modeling and optimization integrating human and material resources

Energy Technology Data Exchange (ETDEWEB)

Martorell, S., E-mail: smartore@iqn.upv.e [Dpto. Ingenieria Quimica y Nuclear, Universidad Politecnica Valencia (Spain); Villamizar, M.; Carlos, S. [Dpto. Ingenieria Quimica y Nuclear, Universidad Politecnica Valencia (Spain); Sanchez, A. [Dpto. Estadistica e Investigacion Operativa Aplicadas y Calidad, Universidad Politecnica Valencia (Spain)

2010-12-15

Maintenance planning is a subject of concern to many industrial sectors as plant safety and business depend on it. Traditionally, the maintenance planning is formulated in terms of a multi-objective optimization (MOP) problem where reliability, availability, maintainability and cost (RAM+C) act as decision criteria and maintenance strategies (i.e. maintenance tasks intervals) act as the only decision variables. However the appropriate development of each maintenance strategy depends not only on the maintenance intervals but also on the resources (human and material) available to implement such strategies. Thus, the effect of the necessary resources on RAM+C needs to be modeled and accounted for in formulating the MOP affecting the set of objectives and constraints. In this paper RAM+C models to explicitly address the effect of human resources and material resources (spare parts) on RAM+C criteria are proposed. This extended model allows accounting for explicitly how the above decision criteria depends on the basic model parameters representing the type of strategies, maintenance intervals, durations, human resources and material resources. Finally, an application case is performed to optimize the maintenance plan of a motor-driven pump equipment considering as decision variables maintenance and test intervals and human and material resources.

Post-warm-up muscle temperature maintenance: blood flow contribution and external heating optimisation.

Science.gov (United States)

Raccuglia, Margherita; Lloyd, Alex; Filingeri, Davide; Faulkner, Steve H; Hodder, Simon; Havenith, George

2016-02-01

Passive muscle heating has been shown to reduce the drop in post-warm-up muscle temperature (Tm) by about 25% over 30 min, with concomitant sprint/power performance improvements. We sought to determine the role of leg blood flow in this cooling and whether optimising the heating procedure would further benefit post-warm-up T m maintenance. Ten male cyclists completed 15-min sprint-based warm-up followed by 30 min recovery. Vastus lateralis Tm (Tmvl) was measured at deep-, mid- and superficial-depths before and after the warm-up, and after the recovery period (POST-REC). During the recovery period, participants wore water-perfused trousers heated to 43 °C (WPT43) with either whole leg heating (WHOLE) or upper leg heating (UPPER), which was compared to heating with electrically heated trousers at 40 °C (ELEC40) and a non-heated control (CON). The blood flow cooling effect on Tmvl was studied comparing one leg with (BF) and without (NBF) blood flow. Warm-up exercise significantly increased Tmvl by ~3 °C at all depths. After the recovery period, BF Tmvl was lower (~0.3 °C) than NBF Tmvl at all measured depths, with no difference between WHOLE versus UPPER. WPT43 reduced the post-warm-up drop in deep-Tmvl (-0.12 °C ± 0.3 °C) compared to ELEC40 (-1.08 ± 0.4 °C) and CON (-1.3 ± 0.3 °C), whereas mid- and superficial-Tmvl even increased by 0.15 ± 0.3 and 1.1 ± 1.1 °C, respectively. Thigh blood flow contributes to the post-warm-up Tmvl decline. Optimising the external heating procedure and increasing heating temperature of only 3 °C successfully maintained and even increased T mvl, demonstrating that heating temperature is the major determinant of post-warm-up Tmvl cooling in this application.

Conversion of a mainframe simulation for maintenance performance to a PC environment

International Nuclear Information System (INIS)

Gertman, D.I.

1990-01-01

The computer model MAPPS, the Maintenance Personnel Performance Simulation, has been developed and validated by the US NRC [Nuclear Regulatory Commission] in order to improve maintenance practices and procedures at nuclear power plants. This model has now been implemented and improved, in a PC [personal computer] environment and renamed MICROMAPPS. The model is stochastically based and users are able to simulate the performance of 2- to 8-person crews for a variety of maintenance tasks under a variety of conditions. These conditions include aspects of crew actions as potentially influenced by the task, the environment, or the personnel involved. For example, the influence of the following factors is currently modeled within the MAPPS computer code: (1) personnel characteristics include but are not limited to intellectual and perceptual motor ability levels, the effect of fatigue and conversely, of rest breaks on performance, stress, communication, supervisor acceptance, motivation, organizational climate, time since the tasks was last performed and the staffing level available; (2) task variables include but are not limited to time allowed, occurrence of shift change, intellectual requirements, perceptual motor requirements, procedures quality, necessity for protective clothing and essentiality of a procedures quality, necessity for protective clothing and essentiality of a subtask; and (3) environment variables include temperature of the workplace, radiation level, and noise levels. The output describing maintainer performance includes subtask and task identification, success proportion, work and wait durations, time spent repeating various subtasks and outcome in terms of errors detected by the crew, false alarms, undetected errors, duration, and the probability of success. The model is comprehensive and allows for the modeling of decision making, trouble-shooting and branching of tasks

Stay Focused! The Effects of Internal and External Focus of Attention on Movement Automaticity in Patients with Stroke

Science.gov (United States)

Kal, E. C.; van der Kamp, J.; Houdijk, H.; Groet, E.; van Bennekom, C. A. M.; Scherder, E. J. A.

2015-01-01

Dual-task performance is often impaired after stroke. This may be resolved by enhancing patients’ automaticity of movement. This study sets out to test the constrained action hypothesis, which holds that automaticity of movement is enhanced by triggering an external focus (on movement effects), rather than an internal focus (on movement execution). Thirty-nine individuals with chronic, unilateral stroke performed a one-leg-stepping task with both legs in single- and dual-task conditions. Attentional focus was manipulated with instructions. Motor performance (movement speed), movement automaticity (fluency of movement), and dual-task performance (dual-task costs) were assessed. The effects of focus on movement speed, single- and dual-task movement fluency, and dual-task costs were analysed with generalized estimating equations. Results showed that, overall, single-task performance was unaffected by focus (p = .341). Regarding movement fluency, no main effects of focus were found in single- or dual-task conditions (p’s ≥ .13). However, focus by leg interactions suggested that an external focus reduced movement fluency of the paretic leg compared to an internal focus (single-task conditions: p = .068; dual-task conditions: p = .084). An external focus also tended to result in inferior dual-task performance (β = -2.38, p = .065). Finally, a near-significant interaction (β = 2.36, p = .055) suggested that dual-task performance was more constrained by patients’ attentional capacity in external focus conditions. We conclude that, compared to an internal focus, an external focus did not result in more automated movements in chronic stroke patients. Contrary to expectations, trends were found for enhanced automaticity with an internal focus. These findings might be due to patients’ strong preference to use an internal focus in daily life. Future work needs to establish the more permanent effects of learning with different attentional foci on re-automating motor

Stay Focused! The Effects of Internal and External Focus of Attention on Movement Automaticity in Patients with Stroke.

Science.gov (United States)

Kal, E C; van der Kamp, J; Houdijk, H; Groet, E; van Bennekom, C A M; Scherder, E J A

2015-01-01

Dual-task performance is often impaired after stroke. This may be resolved by enhancing patients' automaticity of movement. This study sets out to test the constrained action hypothesis, which holds that automaticity of movement is enhanced by triggering an external focus (on movement effects), rather than an internal focus (on movement execution). Thirty-nine individuals with chronic, unilateral stroke performed a one-leg-stepping task with both legs in single- and dual-task conditions. Attentional focus was manipulated with instructions. Motor performance (movement speed), movement automaticity (fluency of movement), and dual-task performance (dual-task costs) were assessed. The effects of focus on movement speed, single- and dual-task movement fluency, and dual-task costs were analysed with generalized estimating equations. Results showed that, overall, single-task performance was unaffected by focus (p = .341). Regarding movement fluency, no main effects of focus were found in single- or dual-task conditions (p's ≥ .13). However, focus by leg interactions suggested that an external focus reduced movement fluency of the paretic leg compared to an internal focus (single-task conditions: p = .068; dual-task conditions: p = .084). An external focus also tended to result in inferior dual-task performance (β = -2.38, p = .065). Finally, a near-significant interaction (β = 2.36, p = .055) suggested that dual-task performance was more constrained by patients' attentional capacity in external focus conditions. We conclude that, compared to an internal focus, an external focus did not result in more automated movements in chronic stroke patients. Contrary to expectations, trends were found for enhanced automaticity with an internal focus. These findings might be due to patients' strong preference to use an internal focus in daily life. Future work needs to establish the more permanent effects of learning with different attentional foci on re-automating motor control

The effects of ergonomic stressors on process tool maintenance and utilization

Energy Technology Data Exchange (ETDEWEB)

Miller, D.

1998-03-31

This study examines ergonomic stressors associated with front-end process tool maintenance, relates them to decreased machine utilization, and proposes solution strategies to reduce their negative impact on productivity. Member company ergonomists observed technicians performing field maintenance tasks on seven different bottleneck tools and recorded ergonomic stressors using SEMaCheck, a graphics-based, integrated checklist developed by Sandia National Laboratories. The top ten stressors were prioritized according to a cost formula that accounted for difficulty, time, and potential errors. Estimates of additional time on a task caused by ergonomic stressors demonstrated that machine utilization could be increased from 6% to 25%. Optimal solution strategies were formulated based on redesign budget, stressor cost, and estimates of solution costs and benefits

Evaluation of Hands-Free Devices for the Display of Maintenance Procedures

Science.gov (United States)

Whitmore, Mihriban; Hoffman, Ronald B.; Litaker, Harry, Jr.; Solem, Jody; Holden, Kritina; Twyford, Evan; Conlee, Carl

2007-01-01

Over the past year, NASA's focus has turned to crewed long duration and exploration missions. On these journeys, crewmembers will be required to execute thousands of procedures to maintain life support systems, check out space suits, conduct science experiments, and perform medical exams. To support the many complex tasks crewmembers undertake in microgravity, NASA is interested in providing crewmembers a hands-free work environment to promote more efficient operations. The overarching objective is to allow crewmembers to use both of their hands for tasks related to their mission, versus holding a paper manual or interacting with a display. The use of advanced, hands-free tools will undoubtedly make the crewmembers task easier, but they can also add to overall task complexity if not properly designed. A leading candidate technology for supporting a hands-free environment is the Head-Mounted Display (HMD). A more recent technology (e-book reader) that could be easily temp-stowed near the work area is also a potential hands-free solution. Previous work at NASA involved the evaluation of several commercially available HMDs for visual quality, comfort, and fit, as well as suitability for use in microgravity. Based on results from this work, three HMDs were selected for further evaluation (along with an e-book reader), using International Space Station (ISS)-like maintenance procedures. Two evaluations were conducted in the Space Station Mockup and Trainer Facility (SSMTF) located at the NASA Johnson Space Center (building 9). The SSMTF is a full scale, medium fidelity replica of the pressurized portions of the ISS. It supports crew training such as ingress and egress, habitability, and emergency procedures. In each of the two evaluations, the participants performed two maintenance procedures. One maintenance procedure involved inspecting air filters in a life support system and replacing them with a clean filter if one were found to be contaminated. The second

Organisational culture in maintenance. A case study at Olkiluoto nuclear power plant

International Nuclear Information System (INIS)

Reiman, T.; Oedewald, P.

2004-05-01

In the publication an assessment of organisational culture in a maintenance organisation is described in detail. The assessment is based on the Contextual Assessment of Organisational Culture (CAOC) methodology developed at VTT. On the basis of the results the development needs of the maintenance work are discussed. The case study was conducted at the maintenance unit of TVO's Olkiluoto nuclear power plant. The research consisted of three phases: characterisation of the maintenance culture (with interviews, survey, group working and a feedback seminar), assessment of the cultural features, and two development seminars for the entire maintenance unit on the basis of the assessment results. Results showed that the personnel were committed to their tasks and they perceive their work as highly meaningful. The personnel were able to perceive very well how their tasks contribute to the organisational goals. Most of the workers were also very proud of their plant and their own proficiency. General job satisfaction was quite good. Low sense of control, weak sense of solidarity and a perceived lack of positive feedback were experienced as the most negative aspects of the culture. Perceived lack of sufficient resources and an unequal distribution of labour were experienced as lowering the sense of control and causing work stress. The work itself was experienced as quite routine-like and the personnel had difficulties in identifying any challenging aspects in their own tasks. Know-how and responsibility are the central aspects that are emphasised in the artefacts (management talk, procedures etc.) of the culture. Nevertheless, it was not always clear what was meant by 'responsibility' or 'responsible behavior'. Despite the obscurity of the concept of responsibility at TVO and the cultural emphasis on certainty, safety and carefulness were considered as values of utmost importance in the organisation. Cohesiveness values were perceived to be quite low, and improvements to them

A holistic framework of degradation modeling for reliability analysis and maintenance optimization of nuclear safety systems

International Nuclear Information System (INIS)

Lin, Yanhui

2016-01-01

Components of nuclear safety systems are in general highly reliable, which leads to a difficulty in modeling their degradation and failure behaviors due to the limited amount of data available. Besides, the complexity of such modeling task is increased by the fact that these systems are often subject to multiple competing degradation processes and that these can be dependent under certain circumstances, and influenced by a number of external factors (e.g. temperature, stress, mechanical shocks, etc.). In this complicated problem setting, this PhD work aims to develop a holistic framework of models and computational methods for the reliability-based analysis and maintenance optimization of nuclear safety systems taking into account the available knowledge on the systems, degradation and failure behaviors, their dependencies, the external influencing factors and the associated uncertainties.The original scientific contributions of the work are: (1) For single components, we integrate random shocks into multi-state physics models for component reliability analysis, considering general dependencies between the degradation and two types of random shocks. (2) For multi-component systems (with a limited number of components):(a) a piecewise-deterministic Markov process modeling framework is developed to treat degradation dependency in a system whose degradation processes are modeled by physics-based models and multi-state models; (b) epistemic uncertainty due to incomplete or imprecise knowledge is considered and a finite-volume scheme is extended to assess the (fuzzy) system reliability; (c) the mean absolute deviation importance measures are extended for components with multiple dependent competing degradation processes and subject to maintenance; (d) the optimal maintenance policy considering epistemic uncertainty and degradation dependency is derived by combining finite-volume scheme, differential evolution and non-dominated sorting differential evolution; (e) the

TPX remote maintenance and shielding

International Nuclear Information System (INIS)

Rennich, M.J.; Nelson, B.E.

1994-01-01

The Tokamak Physics Experiment machine design incorporates comprehensive planning for efficient and safe component maintenance. Three programmatic decisions have been made to insure the successful implementation of this objective. First, the tokamak incorporates radiation shielding to reduce activation of components and limit the dose rate to personnel working on the outside of the machine. This allows most of the ex-vessel equipment to be maintained through conventional ''hands-on'' procedures. Second, to the maximum extent possible, low activation materials will be used inside the shielding volume. This resulted in the selection of Titanium (Ti-6Al-4V) for the vacuum vessel and PFC structures. The third decision stipulated that the primary in-vessel components will be replaced or repaired via remote maintenance tools specifically provided for the task. The component designers have been given the responsibility of incorporating maintenance design and for proving the maintainability of the design concepts in full-scale mockup tests prior to the initiation of final fabrication. Remote maintenance of the TPX machine is facilitated by general purpose tools provided by a special purpose design team. Major tools will include an in-vessel transporter, a vessel transfer system and a large component transfer container. In addition, tools such as manipulators and remotely operable impact wrenches will be made available to the component designers by this group. Maintenance systems will also provide the necessary controls for this equipment

Computer-Based Simulations for Maintenance Training: Current ARI Research. Technical Report 544.

Science.gov (United States)

Knerr, Bruce W.; And Others

Three research efforts that used computer-based simulations for maintenance training were in progress when this report was written: Game-Based Learning, which investigated the use of computer-based games to train electronics diagnostic skills; Human Performance in Fault Diagnosis Tasks, which evaluated the use of context-free tasks to train…

Abnormal externally guided movement preparation in recent-onset schizophrenia is associated with impaired selective attention to external input.

Science.gov (United States)

Smid, Henderikus G O M; Westenbroek, Joanna M; Bruggeman, Richard; Knegtering, Henderikus; Van den Bosch, Robert J

2009-11-30

Several theories propose that the primary cognitive impairment in schizophrenia concerns a deficit in the processing of external input information. There is also evidence, however, for impaired motor preparation in schizophrenia. This provokes the question whether the impaired motor preparation in schizophrenia is a secondary consequence of disturbed (selective) processing of the input needed for that preparation, or an independent primary deficit. The aim of the present study was to discriminate between these hypotheses, by investigating externally guided movement preparation in relation to selective stimulus processing. The sample comprised 16 recent-onset schizophrenia patients and 16 controls who performed a movement-precuing task. In this task, a precue delivered information about one, two or no parameters of a movement summoned by a subsequent stimulus. Performance measures and measures derived from the electroencephalogram showed that patients yielded smaller benefits from the precues and showed less cue-based preparatory activity in advance of the imperative stimulus than the controls, suggesting a response preparation deficit. However, patients also showed less activity reflecting selective attention to the precue. We therefore conclude that the existing evidence for an impairment of externally guided motor preparation in schizophrenia is most likely due to a deficit in selective attention to the external input, which lends support to theories proposing that the primary cognitive deficit in schizophrenia concerns the processing of input information.

Optimization of the preventive maintenance plan of a series components system

Energy Technology Data Exchange (ETDEWEB)

Duarte, Jose A. Caldeira [Mathematical Department, Instituto Politecnico de Setubal/Escola Superior de Tecnologia de Setubal, Campus do IPS, Estefanilha, 2914-508 Setubal (Portugal)]. E-mail: jduarte@est.ips.pt; Craveiro, Joao C. Taborda A. [MIIT, Manutencao Industrial Informatizada e Tecnologia, Lda, Av. Elias Garcia, 123, 5o, Lisbon (Portugal); Trigo, Tomas Pedro [MIIT, Manutencao Industrial Informatizada e Tecnologia, Lda, Av. Elias Garcia, 123, 5o, Lisbon (Portugal)

2006-04-15

One of the most critical problems in preventive maintenance is the determination of the optimum frequency to perform preventive maintenance in equipment, in order to ensure its availability. In this paper, we propose an algorithm to solve the previous problem for equipment that exhibit linearly increasing hazard rate and constant repair rate. Based on this algorithm, we have developed another one to solve the problem of maintenance management of a series system based on preventive maintenance over the different system components. We assume that all components of the system still exhibit linearly increasing hazard rate and constant repair rate and that preventive maintenance would bring the system to the as good as new condition. We define a cost function for maintenance tasks (preventive and corrective) for the system. The algorithm calculates the interval of time between preventive maintenance actions for each component, minimizing the costs, and in such a way that the total downtime, in a certain period of time, does not exceed a predetermined value.

Relative importance of expertise, lifting height and weight lifted on posture and lumbar external loading during a transfer task in manual material handling.

Science.gov (United States)

Plamondon, André; Larivière, Christian; Delisle, Alain; Denis, Denys; Gagnon, Denis

2012-01-01

The objective of this study was to measure the effect size of three important factors in manual material handling, namely expertise, lifting height and weight lifted. The effect of expertise was evaluated by contrasting 15 expert and 15 novice handlers, the effect of the weight lifted with a 15-kg box and a 23-kg box and the effect of lifting height with two different box heights: ground level and a 32 cm height. The task consisted of transferring a series of boxes from a conveyor to a hand trolley. Lifting height and weight lifted had more effect size than expertise on external back loading variables (moments) while expertise had low impact. On the other hand, expertise showed a significant effect of posture variables on the lumbar spine and knees. All three factors are important, but for a reduction of external back loading, the focus should be on the lifting height and weight lifted. The objective was to measure the effect size of three important factors in a transfer of boxes from a conveyor to a hand trolley. Lifting height and weight lifted had more effect size than expertise on external back loading variables but expertise was a major determinant in back posture.

Translational research: bridging the gap between long-term weight loss maintenance research and practice.

Science.gov (United States)

Akers, Jeremy D; Estabrooks, Paul A; Davy, Brenda M

2010-10-01

The number of US adults classified as overweight or obese has dramatically increased in the past 25 years, resulting in a significant body of research addressing weight loss and weight loss maintenance. However, little is known about the potential of weight loss maintenance interventions to be translated into actual practice settings. Thus, the purpose of this article is to determine the translation potential of published weight loss maintenance intervention studies by determining the extent to which they report information across the reach, efficacy/effectiveness, adoption, implementation, and maintenance (RE-AIM) framework. A secondary purpose is to provide recommendations for research based on these findings. To identify relevant research articles, a literature search was conducted using four databases; 19 weight loss maintenance intervention studies were identified for inclusion. Each article was evaluated using the RE-AIM Coding Sheet for Publications to determine the extent to which dimensions related to internal and external validity were reported. Approximately half of the articles provided information addressing three RE-AIM dimensions, yet only a quarter provided information addressing adoption and maintenance. Significant gaps were identified in understanding external validity, and metrics that could facilitate the translation of these interventions from research to practice are presented. Based upon this review, it is unknown how effective weight loss maintenance interventions could be in real-world situations, such as clinical or community practice settings. Future studies should be planned to address how weight loss maintenance intervention programs will be adopted and maintained, with special attention to costs for participants and for program implementation. Copyright © 2010 American Dietetic Association. Published by Elsevier Inc. All rights reserved.

Tribological diagnostics as a precondition for maintenance

International Nuclear Information System (INIS)

Jolevski, Tome

1999-01-01

The concept of maintenance in one industrial system usually represents a sum of constructions and rules that point out to several facts: 1) over which technical system the maintenance should be applied, 2) when it should be applied and 3) on which way it should be organized. In our real industrial systems the contemporary maintenance of the technical systems is not enough. Also, other contemporary measures whose basic task is to prevent unplanned stoppages as well as damages in the production process are insufficient. The equipment of the technical systems with devices for permanent monitoring of the condition, in other words with devices for technical diagnostic is unsatisfactorily, with a small exemption of the devices for vibration diagnostic monitoring of the condition in real time. The tribological diagnostics, using the procedures and methods without destroying as well as measuring and monitoring the condition of the lubrication devices, allows to find out the real status of the technical systems in operation. On that basic it is possible to undertake correct maintenance measures which would provide promising and safe operation of the technical systems. (Author)

Social Ontology Documentation for Knowledge Externalization

Science.gov (United States)

Aranda-Corral, Gonzalo A.; Borrego-Díaz, Joaquín; Jiménez-Mavillard, Antonio

Knowledge externalization and organization is a major challenge that companies must face. Also, they have to ask whether is possible to enhance its management. Mechanical processing of information represents a chance to carry out these tasks, as well as to turn intangible knowledge assets into real assets. Machine-readable knowledge provides a basis to enhance knowledge management. A promising approach is the empowering of Knowledge Externalization by the community (users, employees). In this paper, a social semantic tool (called OntoxicWiki) for enhancing the quality of knowledge is presented.

Decision, Annex 3[Organizational structure of the Division for reactor maintenance]; Prilog br. 3, Odluka

Energy Technology Data Exchange (ETDEWEB)

Pavicevic, M [Reaktor RA, Odelenje odrzavanja, Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

1965-12-15

The objective of the decision about the change in the organizational scheme of the Division for RA reactor maintenance is to achieve efficiency. The tasks are precisely defined as to divide the maintenance and repair tasks from special ones related to improvement of reactor operation its applicability. [Serbo-Croat] U cilju poboljsanja organizacije rada Odelenja odrzavanja reaktora RA, kao i efikasnijeg koriscenja raspolozivog kadra izvrsice se razgranicenje poslova odrzavanja i remonta od posebnih zadataka koji se odnose na poboljsanje rada reaktora i povecanje njegovih mogucnosti.

Optimisation of maintenance and inspection work in nuclear power plants

International Nuclear Information System (INIS)

Meyer, V.

1996-01-01

The long-term planning and comparative evaluation of inspection and maintenance intervals as well as results of electric components and machinery have to be intensified in order to shorten maintenance shut-down periods, e.g. of the Grohnde reactor station, thus improving the availability of the plant and the specific electricity generation cost. Economically efficient maintenance has to be based on an efficient organisational structure. Outsourcing of less plant-specific work and tasks offers the possibility for in-house personnel to concentrate on their core competences. All the measures discussed contribute to improving the economic efficiency of the nuclear power plants. (orig./DG) [de

Robustness evaluation of cutting tool maintenance planning for soft ground tunneling projects

Directory of Open Access Journals (Sweden)

Alena Conrads

2018-03-01

Full Text Available Tunnel boring machines require extensive maintenance and inspection effort to provide a high availability. The cutting tools of the cutting wheel must be changed timely upon reaching a critical condition. While one possible maintenance strategy is to change tools only when it is absolutely necessary, tools can also be changed preventively to avoid further damages. Such different maintenance strategies influence the maintenance duration and the overall project performance. However, determine downtime related to a particular maintenance strategy is still a challenging task. This paper shows an analysis of the robustness to achieve the planned project performance of a maintenance strategy considering uncertainties of wear behavior of the cutting tools. A simulation based analysis is presented, implementing an empirical wear prediction model. Different strategies of maintenance planning are compared by performing a parameter variation study including Monte-Carlo simulations. The maintenance costs are calculated and evaluated with respect to their robustness. Finally, an improved and robust maintenance strategy has been determined. Keywords: Mechanized tunneling, Maintenance, Wear of cutting tools, Process simulation, Robustness, Uncertainty modeling

Transfer of training from one working memory task to another: Behavioural and neural evidence

Directory of Open Access Journals (Sweden)

Erin L. Beatty

2015-06-01

Full Text Available N-back working memory (WM tasks necessitate the maintenance and updating of dynamic rehearsal sets during performance. The delayed matching-to-sample (dMTS task is another WM task, which in turn involves the encoding, maintenance, and retrieval of stimulus representations in sequential order. Because both n-back and dMTS engage WM function, we hypothesized that compared to a control task not taxing WM, training on the n-back task would be associated with better performance on dMTS by virtue of training a shared mental capacity. We tested this hypothesis by randomly assigning subjects (N = 43 to train on either the n-back (including 2-back and 3-back levels or an active control task. Following training, dMTS was administered in the fMRI scanner. The n-back group performed marginally better than the active control group on dMTS. In addition, although the n-back group improved more on the less difficult 2-back level than the more difficult 3-back level across training sessions, it was improvement on the 3-back level that accounted for 21% of the variance in dMTS performance. For the control group, improvement in training across sessions was unrelated to dMTS performance. At the neural level, greater activation in the left inferior frontal gyrus, right posterior parietal cortex and the cerebellum distinguished the n-back group from the control group in the maintenance phase of dMTS. Degree of improvement on the 3-back level across training sessions was correlated with activation in right lateral prefrontal and motor cortices in the maintenance phase of dMTS. Our results suggest that although n-back training is more likely to improve performance in easier blocks, it is improvement in more difficult blocks that is predictive of performance on a target task drawing on WM. In addition, the extent to which training on a task can transfer to another task is likely due to the engagement of shared cognitive capacities and underlying neural substrates�

Reliability Centred Maintenance (RCM) Analysis of Laser Machine in Filling Lithos at PT X

Science.gov (United States)

Suryono, M. A. E.; Rosyidi, C. N.

2018-03-01

PT. X used automated machines which work for sixteen hours per day. Therefore, the machines should be maintained to keep the availability of the machines. The aim of this research is to determine maintenance tasks according to the cause of component’s failure using Reliability Centred Maintenance (RCM) and determine the amount of optimal inspection frequency which must be performed to the machine at filling lithos process. In this research, RCM is used as an analysis tool to determine the critical component and find optimal inspection frequencies to maximize machine’s reliability. From the analysis, we found that the critical machine in filling lithos process is laser machine in Line 2. Then we proceed to determine the cause of machine’s failure. Lastube component has the highest Risk Priority Number (RPN) among other components such as power supply, lens, chiller, laser siren, encoder, conveyor, and mirror galvo. Most of the components have operational consequences and the others have hidden failure consequences and safety consequences. Time-directed life-renewal task, failure finding task, and servicing task can be used to overcome these consequences. The results of data analysis show that the inspection must be performed once a month for laser machine in the form of preventive maintenance to lowering the downtime.

When attention wanders: Pupillometric signatures of fluctuations in external attention.

Science.gov (United States)

Konishi, Mahiko; Brown, Kevin; Battaglini, Luca; Smallwood, Jonathan

2017-11-01

Attention is not always directed to events in the external environment. On occasion our thoughts wander to people and places distant from the here and now. Sometimes, this lack of external attention can compromise ongoing task performance. In the current study we set out to understand the extent to which states of internal and external attention can be determined using pupillometry as an index of ongoing cognition. In two experiments we found that periods of slow responding were associated with elevations in the baseline pupil signal over three and a half seconds prior to a behavioural response. In the second experiment we found that unlike behavioural lapses, states of off-task thought, particularly those associated with a focus on the past and with an intrusive quality, were associated with reductions in the size of the pupil over the same window prior to the probe. These data show that both states of large and small baseline pupil size are linked to states when attention is not effectively focused on the external environment, although these states have different qualities. More generally, these findings illustrate that subjective and objective markers of task performance may not be equivalent and underscore the importance of developing objective indicators that can allow these different states to be understood. Copyright © 2017 Elsevier B.V. All rights reserved.

Harsh Parenting and Child Externalizing Behavior: Skin Conductance Level Reactivity as a Moderator

OpenAIRE

Erath, Stephen A.; El-Sheikh, Mona; Cummings, E. Mark

2009-01-01

Skin conductance level reactivity (SCLR) was examined as a moderator of the association between harsh parenting and child externalizing behavior. Participants were 251 boys and girls (8–9 years). Mothers and fathers provided reports of harsh parenting and their children’s externalizing behavior; children also provided reports of harsh parenting. SCLR was assessed in response to a socioemotional stress task and a problem-solving challenge task. Regression analyses revealed that the association...

Tokamak Fusion Core Experiment maintenance study

International Nuclear Information System (INIS)

Snyder, A.M.; Watts, K.D.

1985-01-01

The recently completed Tokamak Fusion Core Experiment (TFCX) design project was carried out to investigate potential next generation tokamak concepts. An important aspect of this project was the early development and incorporation of remote maintainability throughout the design process. This early coordination and incorporation of maintenance aspects to the design of the device and facilities would assure that the machine could ultimately be maintained and repaired in an efficient and cost effective manner. To meet this end, a rigorously formatted engineering trade study was performed to determine the preferred configuration for the TFCX reactor based primarily on maintenance requirements. The study indicated that the preferred design was one with an external vacuum vessel and torrodial field coils that could be removed via a simple radial motion. The trade study is presented and the preferred TFCX configuration is described

Conversion of a mainframe simulation for maintenance performance to a PC environment

International Nuclear Information System (INIS)

Gertman, D.I.

1991-01-01

A computer-based simulation capable of generating human error probabilities (HEPs) for maintenance activities is presented. The HEPs are suitable for use in probabilistic risk assessments (PRAs) and are an important source of information for data management systems such as NUCLARR- the Nuclear Computerized Library for Assessing Reactor Reliability. (1) The basic computer model MAPPS--the maintenance personnel performance simulation has been developed and validated by the US NRC in order to improve maintenance practices and procedures at nuclear power plants. This model validated previously, has now been implemented and improved, in a PC environment, and renamed MicroMAPPS. The model is stochastically based, able to simulate the performance of 2 to 15 person crews for a variety of maintenance conditions. These conditions include aspects of crew actions as potentially influenced by the task, the environment, or characteristics of the personnel involved. The nature of the software code makes it particularly appropriate for determining changes in HEP rates due to fluctuations in important task, environment,. or personnel parameters. The presentation presents a brief review of the mainframe version of the code and presents a summarization of the enhancements which dramatically change the nature of the human computer interaction

Complete guide to preventive and predictive maintenance

CERN Document Server

Levitt, Joel

2011-01-01

This book shares the best practices, mistakes, victories, and essential steps for success which the author has gleaned from working with countless organizations. Unlike other books that only focus on the engineering issues (task lists) or management issues (CMMS), this in-depth resource is the first to give true emphasize to the four aspects of success in preventive maintenance systems - engineering, management, economic, and psychological - thereby enabling readers to have a balanced view and understanding of what is happening in their organizations. Additionally, it blends concrete actionable steps and structures with the theory behind the steps. It includes check sheets, history of PM, stories, photographs, and case histories. It contains a glossary of terms. It provides sample task lists for a variety of equipment with some of the logic behind each task. It offers templates for developing your own tasking. It includes protocols for detailed economic analysis with examples.

Individual Differences Influencing Immediate Effects of Internal and External Focus Instructions on Children's Motor Performance.

Science.gov (United States)

van Abswoude, Femke; Nuijen, Nienke B; van der Kamp, John; Steenbergen, Bert

2018-06-01

A large pool of evidence supports the beneficial effect of an external focus of attention on motor skill performance in adults. In children, this effect has been studied less and results are inconclusive. Importantly, individual differences are often not taken into account. We investigated the role of working memory, conscious motor control, and task-specific focus preferences on performance with an internal and external focus of attention in children. Twenty-five children practiced a golf putting task in both an internal focus condition and external focus condition. Performance was defined as the average distance toward the hole in 3 blocks of 10 trials. Task-specific focus preference was determined by asking how much effort it took to apply the instruction in each condition. In addition, working memory capacity and conscious motor control were assessed. Children improved performance in both the internal focus condition and external focus condition (ŋ p 2  = .47), with no difference between conditions (ŋ p 2  = .01). Task-specific focus preference was the only factor moderately related to the difference between performance with an internal focus and performance with an external focus (r = .56), indicating better performance for the preferred instruction in Block 3. Children can benefit from instruction with both an internal and external focus of attention to improve short-term motor performance. Individual, task-specific focus preference influenced the effect of the instructions, with children performing better with their preferred focus. The results highlight that individual differences are a key factor in the effectiveness in children's motor performance. The precise mechanisms underpinning this effect warrant further research.

Pre-conceptual design assessment of DEMO remote maintenance

Energy Technology Data Exchange (ETDEWEB)

Loving, A., E-mail: antony.loving@ccfe.ac.uk [EURATOM/Culham Center Fusion Energy, Culham Science Centre, OX14 3DB, Abingdon (United Kingdom); Crofts, O.; Sykes, N.; Iglesias, D.; Coleman, M.; Thomas, J. [EURATOM/Culham Center Fusion Energy, Culham Science Centre, OX14 3DB, Abingdon (United Kingdom); Harman, J. [EFDA Close Support Unit Garching, Boltzmannstaße 2, D-85748 Garching Bei München (Germany); Fischer, U. [Karlsruhe Institute of Technology, Institute for Neutron Physics and Reactor Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany); Sanz, J. [Instituto de Fusión Nuclear/UPM, Madrid (Spain); Siuko, M. [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT (Finland); Mittwollen, M. [Karlsruhe Institute of Technology, Institut für Fördertechnik und Logistiksysteme, Gotthard-Franz-Straße 8, Geb.50.38, 76131 Karlsruhe (Germany)

2014-10-15

EDFA, as part of the Power Plant Physics and Technology programme, has been working on the pre-conceptual design of a Demonstration Power Plant (DEMO). As part of this programme, a review of the remote maintenance strategy considered maintenance solutions compatible with expected environmental conditions, whilst showing potential for meeting the plant availability targets. A key finding was that, for practical purposes, the expected radiation levels prohibit the use of complex remote handling operations to replace the first wall. In 2012/2013, these remote maintenance activities were further extended, providing an insight into the requirements, constraints and challenges. In particular, the assessment of blanket and divertor maintenance, in light of the expected radiation conditions and availability, has elaborated the need for a very different approach from that of ITER. This activity has produced some very informative virtual reality simulations of the blanket segments and pipe removal that are exceptionally valuable in communicating the complexity and scale of the required operations. Through these simulations, estimates of the maintenance task durations have been possible demonstrating that a full replacement of the blankets within 6 months could be achieved. The design of the first wall, including the need to use sacrificial limiters must still be investigated. In support of the maintenance operations, a first indication of the requirements of an Active Maintenance Facility (AMF) has been elaborated.

Advanced Maintenance Simulation by Means of Hand-Based Haptic Interfaces

Science.gov (United States)

Nappi, Michele; Paolino, Luca; Ricciardi, Stefano; Sebillo, Monica; Vitiello, Giuliana

Aerospace industry has been involved in virtual simulation for design and testing since the birth of virtual reality. Today this industry is showing a growing interest in the development of haptic-based maintenance training applications, which represent the most advanced way to simulate maintenance and repair tasks within a virtual environment by means of a visual-haptic approach. The goal is to allow the trainee to experiment the service procedures not only as a workflow reproduced at a visual level but also in terms of the kinaesthetic feedback involved with the manipulation of tools and components. This study, conducted in collaboration with aerospace industry specialists, is aimed to the development of an immersive virtual capable of immerging the trainees into a virtual environment where mechanics and technicians can perform maintenance simulation or training tasks by directly manipulating 3D virtual models of aircraft parts while perceiving force feedback through the haptic interface. The proposed system is based on ViRstperson, a virtual reality engine under development at the Italian Center for Aerospace Research (CIRA) to support engineering and technical activities such as design-time maintenance procedure validation, and maintenance training. This engine has been extended to support haptic-based interaction, enabling a more complete level of interaction, also in terms of impedance control, and thus fostering the development of haptic knowledge in the user. The user’s “sense of touch” within the immersive virtual environment is simulated through an Immersion CyberForce® hand-based force-feedback device. Preliminary testing of the proposed system seems encouraging.

Knowledge Pipeline: A Task Oriented Way to Implement Knowledge Management

International Nuclear Information System (INIS)

Pan Jiajie

2014-01-01

Concept of knowledge pipeline: There are many pipelines named by tasks or business processes in an organization. Knowledge contributors put knowledge to its corresponding pipelines. A maintenance team could keep the knowledge in pipelines clear and valid. Users could get knowledge just like opening a faucet in terms of their tasks or business processes

Automatic scheduling of maintenance work in nuclear power plants

International Nuclear Information System (INIS)

Kasahara, T.; Nishizawa, Y.; Kato, K.; Kiguchi, T.

1987-01-01

An automatic scheduling method for maintenance work in nuclear power plants has been developed using an AI technique. The purpose of this method is to help plant operators by adjusting the time schedule of various kinds of maintenance work so that incorrect ordering or timing of plant manipulations does not cause undersirable results, such as a plant trip. The functions of the method were tested by off-line simulations. The results show that the method can produce a satisfactory schedule of plant component manipulations without interference between the tasks and plant conditions

Human area MT+ shows load-dependent activation during working memory maintenance with continuously morphing stimulation.

Science.gov (United States)

Galashan, Daniela; Fehr, Thorsten; Kreiter, Andreas K; Herrmann, Manfred

2014-07-11

Initially, human area MT+ was considered a visual area solely processing motion information but further research has shown that it is also involved in various different cognitive operations, such as working memory tasks requiring motion-related information to be maintained or cognitive tasks with implied or expected motion.In the present fMRI study in humans, we focused on MT+ modulation during working memory maintenance using a dynamic shape-tracking working memory task with no motion-related working memory content. Working memory load was systematically varied using complex and simple stimulus material and parametrically increasing retention periods. Activation patterns for the difference between retention of complex and simple memorized stimuli were examined in order to preclude that the reported effects are caused by differences in retrieval. Conjunction analysis over all delay durations for the maintenance of complex versus simple stimuli demonstrated a wide-spread activation pattern. Percent signal change (PSC) in area MT+ revealed a pattern with higher values for the maintenance of complex shapes compared to the retention of a simple circle and with higher values for increasing delay durations. The present data extend previous knowledge by demonstrating that visual area MT+ presents a brain activity pattern usually found in brain regions that are actively involved in working memory maintenance.

Maintenance optimization in nuclear power plants through genetic algorithms

International Nuclear Information System (INIS)

Munoz, A.; Martorell, S.; Serradell, V.

1999-01-01

Establishing suitable scheduled maintenance tasks leads to optimizing the reliability of nuclear power plant safety systems. The articles addresses this subject, whilst endeavoring to tackle an overall optimization process for component availability and safety systems through the use of genetic algorithms. (Author) 20 refs

Balance maintenance as an acquired motor skill: Delayed gains and robust retention after a single session of training in a virtual environment.

Science.gov (United States)

Elion, Orit; Sela, Itamar; Bahat, Yotam; Siev-Ner, Itzhak; Weiss, Patrice L Tamar; Karni, Avi

2015-06-03

Does the learning of a balance and stability skill exhibit time-course phases and transfer limitations characteristic of the acquisition and consolidation of voluntary movement sequences? Here we followed the performance of young adults trained in maintaining balance while standing on a moving platform synchronized with a virtual reality road travel scene. The training protocol included eight 3 min long iterations of the road scene. Center of Pressure (CoP) displacements were analyzed for each task iteration within the training session, as well as during tests at 24h, 4 weeks and 12 weeks post-training to test for consolidation phase ("offline") gains and assess retention. In addition, CoP displacements in reaction to external perturbations were assessed before and after the training session and in the 3 subsequent post-training assessments (stability tests). There were significant reductions in CoP displacements as experience accumulated within session, with performance stabilizing by the end of the session. However, CoP displacements were further reduced at 24h post-training (delayed "offline" gains) and these gains were robustly retained. There was no transfer of the practice-related gains to performance in the stability tests. The time-course of learning the balance maintenance task, as well as the limitation on generalizing the gains to untrained conditions, are in line with the results of studies of manual movement skill learning. The current results support the conjecture that a similar repertoire of basic neuronal mechanisms of plasticity may underlay skill (procedural, "how to" knowledge) acquisition and skill memory consolidation in voluntary and balance maintenance tasks. Copyright © 2015 Elsevier B.V. All rights reserved.

Tasks of physicists and graduated engineers in diagnostic radiology

International Nuclear Information System (INIS)

Angerstein, W.

1987-01-01

The tasks of physicists and engineers in diagnostic radiology are compiled and trends of development are discussed. Specific duties can be selected from these tasks for each department and physicist individually. An attempt is made to characterize the specific tasks of medical physics. The most important tasks are concerning subjects of (1) investment planning, (2) quality control and quality assurance, (3) service and maintenance, (4) radiation protection and electrical safety, (5) development, testing and adaption of equipment, (6) assistance in running the radiologic department, (7) research, (8) pre- and postgraduate training, (9) educational training, (10) miscellaneous. (author)

33 CFR 385.22 - Independent scientific review and external peer review.

Science.gov (United States)

2010-07-01

... external peer review. 385.22 Section 385.22 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT... RESTORATION PLAN CERP Implementation Processes § 385.22 Independent scientific review and external peer review... members, shall not attempt to influence the panel's review or assign this panel any other tasks, nor...

Designer's guidebook for first wall/blanket/shield assembly, maintenance, and repair

Energy Technology Data Exchange (ETDEWEB)

1983-12-30

This is the initial issue of the guidebook. Since a guidebook of this type must incorporate information concerning a wide range of subjects, much additional data will eventually be included. The guidebook will document, in summary and easily referenceable form, data, designs, design concepts, design guidelines and background information useful to the FWBS and to the Maintenance System designer. In providing guidelines for the AMR of the FWBS, the guidebook must, of necessity, include guidelines for all aspects of maintenance associated with the FWBS. These include most maintenance operations within the reactor room necessary to gain access, identify faults, and handle equipment related to FWBS maintenance. In addition, the guidelines include those required to define facility requirements for handling and repair of FWBS and related reactor components external to the reactor room. Particular emphasis is given to remote maintenance design and operations.

External query expansion in the blogosphere

NARCIS (Netherlands)

Weerkamp, W.; de Rijke, M.; Voorhees, E.M.; Buckland, L.P.

2009-01-01

We describe the participation of the University of Amsterdam’s ILPS group in the blog track at TREC 2008. We mainly explored different ways of using external corpora to expand the original query. In the blog post retrieval task we did not succeed in improving over a simple baseline (equal weights

Maintenance Personnel Performance Simulation (MAPPS) model: description of model content, structure, and sensitivity testing. Volume 2

International Nuclear Information System (INIS)

Siegel, A.I.; Bartter, W.D.; Wolf, J.J.; Knee, H.E.

1984-12-01

This volume of NUREG/CR-3626 presents details of the content, structure, and sensitivity testing of the Maintenance Personnel Performance Simulation (MAPPS) model that was described in summary in volume one of this report. The MAPPS model is a generalized stochastic computer simulation model developed to simulate the performance of maintenance personnel in nuclear power plants. The MAPPS model considers workplace, maintenance technician, motivation, human factors, and task oriented variables to yield predictive information about the effects of these variables on successful maintenance task performance. All major model variables are discussed in detail and their implementation and interactive effects are outlined. The model was examined for disqualifying defects from a number of viewpoints, including sensitivity testing. This examination led to the identification of some minor recalibration efforts which were carried out. These positive results indicate that MAPPS is ready for initial and controlled applications which are in conformity with its purposes

The use of condition monitoring information for maintenance planning and decision-making

Energy Technology Data Exchange (ETDEWEB)

Laakso, K.; Rosqvist, T. [VTT Industrial Systems (Finland); Paulsen, J.L. [Risoe National Lab., Roskilde (Denmark)

2002-12-01

A survey is presented outlining the use of condition monitoring information in three Nordic nuclear power plants. The questions of the survey relate to the role of condition monitoring in strategic, as well as operative, maintenance planning and decision-making. The survey indicates that condition monitoring is increasingly implemented at nuclear power plants, but very selectively and in a rather slow pace for predictive maintenance. A combined strategy of condition based maintenance and predetermined preventive maintenance is applied for important equipment such as main circulation pumps and steam turbines. A realistic aim is to reduce the number of costly or error prone maintenance and disassembling inspection activities by condition monitoring given that the approach enables a good diagnosis and prediction. Systematic follow-up and analysis of such condition monitoring information followed by a case-specific planning and decision making of timely and rightly directed maintenance actions can justify an extension of the intervals of a number of predetermined inspection, maintenance or periodic testing tasks. (au)

Reliability Centered Maintenance as a tool for plant life extension

International Nuclear Information System (INIS)

Elliott, J.O.; Mulay, J.N.; Nakahara, Y.

1991-01-01

Currently in the nuclear industry there is a growing interest in lowering the cost and complexity of maintenance activities while at the same time improving plant reliability and safety in an effort to prepare for the technical and regulatory challenges of life extension. This seemingly difficult task is being aided by the introduction of a maintenance philosophy developed originally by the airline industry and subsequently applied with great success both in that industry and the U.S. military services. Reliability Centered Maintenance (RCM), in its basic form, may be described as a consideration of reliability and maintenance problems from a systems level approach, allowing a focus on preservation of system function as the aim of a maintenance program optimized for both safety and economics. It is this systematic view of plant maintenance, with the emphasis on overall functions rather than individual parts and components which sets RCM apart from past nuclear plant maintenance philosophies. It is also the factor which makes application of RCM an ideal first step in development of strategies for life extension, both for aging plants, and for plants just beginning their first license term. (J.P.N.)

Effective maintenance practices to manage system aging

International Nuclear Information System (INIS)

Chockie, A.; Bjorkelo, K.

1992-01-01

For a variety of economic and technical reasons, there has been a growing concern with the aging of complex systems and components and the role that maintenance can play in reducing this degradation. A study for the Nuclear Regulatory Commission was recently undertaken to identify effective maintenance practices that could be adapted by the nuclear industry in the United States to assist in managing the aging degradation of plant systems and components. Four organizations were examined to assess the influence that their maintenance programs have on their ability to address the systems and component aging degradation issues. An effective maintenance program was found to be essential to the management of system and component aging. The four key elements of an effective maintenance program that are important to an aging management program were identified. These are: the selection of critical systems and components; the development of an understanding of aging through the collection and analysis of equipment performance information; the development of appropriate preventive and predictive maintenance tasks to manage equipment and system aging degradation; the use of feedback mechanisms to continuously improve the management of aging systems and components. These elements were found to be common to all four organizations. In examining how the four organizations have structured their maintenance programs to include these key elements provides valuable lessons not only for the nuclear power industry, but also for any industrial organization that is concerned with the management of system and component aging degradation. This document provides detail, of these studies

Proceedings of the workshop on better nuclear plant maintenance: improving human and organisational performance

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-04-05

A significant proportion of nuclear plant events is attributable to failures that take place during maintenance and periodic testing. Human and organisational factors are frequently identified as making a major contribution to these events. Despite this recognition, licensee and regulatory oversight in the human and organisational area has tended to focus more on operational matters than maintenance. Owing to the importance of human and organisational performance on nuclear plant maintenance, the CSNI Special Experts' Group on Human and Organisational Factors (SEGHOF) hosted a workshop entitled 'Better nuclear plant maintenance: improving human and organisational performance'. The workshop provided an international forum for staff from nuclear plants, research bodies, and regulators to discuss human and organisational challenges to maintenance, and initiatives to support effective performance. Over 60 participants from about 20 countries participated. The workshop was divided into five sessions: 1) International guidance to improve maintenance performance; 2) Lessons learned through maintenance operating experience; 3) Licensee initiatives to support reliable maintenance; 4) Regulatory approaches to assuring effective licensee maintenance; and 5) Recent trends and their impact on maintenance. Sessions commenced with oral presentations of papers followed by break-out and plenary discussions. Session 4 on regulatory approaches included short presentations from ten regulatory bodies and was followed by discussion comparing these approaches. The main findings of the workshop concern: the retirements of experienced staff; the increasing use of contractors to perform maintenance activities; the use of skill-broadening in maintenance; the role of supervisors at the plant level; the organisational changes that are used to optimise the use of plant staff resources; the effective planning of maintenance tasks; the time allowed to complete maintenance tasks; the development

Diminished neural responses predict enhanced intrinsic motivation and sensitivity to external incentive.

Science.gov (United States)

Marsden, Karen E; Ma, Wei Ji; Deci, Edward L; Ryan, Richard M; Chiu, Pearl H

2015-06-01

The duration and quality of human performance depend on both intrinsic motivation and external incentives. However, little is known about the neuroscientific basis of this interplay between internal and external motivators. Here, we used functional magnetic resonance imaging to examine the neural substrates of intrinsic motivation, operationalized as the free-choice time spent on a task when this was not required, and tested the neural and behavioral effects of external reward on intrinsic motivation. We found that increased duration of free-choice time was predicted by generally diminished neural responses in regions associated with cognitive and affective regulation. By comparison, the possibility of additional reward improved task accuracy, and specifically increased neural and behavioral responses following errors. Those individuals with the smallest neural responses associated with intrinsic motivation exhibited the greatest error-related neural enhancement under the external contingency of possible reward. Together, these data suggest that human performance is guided by a "tonic" and "phasic" relationship between the neural substrates of intrinsic motivation (tonic) and the impact of external incentives (phasic).

Insula tuning towards external eating versus interoceptive input in adolescents with overweight and obesity.

Science.gov (United States)

Mata, Fernanda; Verdejo-Roman, Juan; Soriano-Mas, Carles; Verdejo-Garcia, Antonio

2015-10-01

This study was aimed to examine if adolescent obesity is associated with alterations of insula function as indexed by differential correlations between insula activation and perception of interoceptive feedback versus external food cues. We hypothesized that, in healthy weight adolescents, insula activation will positively correlate with interoceptive sensitivity, whereas in excess weight adolescents, insula activation will positively correlate with sensitivity towards external cues. Fifty-four adolescents (age range 12-18), classified in two groups as a function of BMI, excess weight (n = 22) and healthy weight (n = 32), performed the Risky-Gains task (sensitive to insula function) inside an fMRI scanner, and completed the heartbeat perception task (measuring interoceptive sensitivity) and the Dutch Eating Behaviour Questionnaire (measuring external eating as well as emotional eating and restraint) outside the scanner. We found that insula activation during the Risky-Gains task positively correlated with interoceptive sensitivity and negatively correlated with external eating in healthy weight adolescents. Conversely, in excess weight adolescents, insula activation positively correlated with external eating and negatively correlated with interoceptive sensitivity, arguably reflecting obesity related neurocognitive adaptations. In excess weight adolescents, external eating was also positively associated with caudate nucleus activation, and restrained eating was negatively associated with insula activation. Our findings suggest that adolescent obesity is associated with disrupted tuning of the insula system towards interoceptive input. Copyright © 2015 Elsevier Ltd. All rights reserved.

Building and integrating reliability models in a Reliability-Centered-Maintenance approach

International Nuclear Information System (INIS)

Verite, B.; Villain, B.; Venturini, V.; Hugonnard, S.; Bryla, P.

1998-03-01

Electricite de France (EDF) has recently developed its OMF-Structures method, designed to optimize preventive maintenance of passive structures such as pipes and support, based on risk. In particular, reliability performances of components need to be determined; it is a two-step process, consisting of a qualitative sort followed by a quantitative evaluation, involving two types of models. Initially, degradation models are widely used to exclude some components from the field of preventive maintenance. The reliability of the remaining components is then evaluated by means of quantitative reliability models. The results are then included in a risk indicator that is used to directly optimize preventive maintenance tasks. (author)

SOFTM: a software maintenance expert system in Prolog

DEFF Research Database (Denmark)

Pau, L.; Negret, J. M.

1988-01-01

A description is given of a knowledge-based system called SOFTM, serving the following purposes: (1) assisting a software programmer or analyst in his application code maintenance tasks, (2) generating and updating automatically software correction documentation, (3) helping the end user register......, and on interfacing capabilities of Prolog II to a variety of other languages...

The Effects of Locus of Control and Task Difficulty on Procrastination.

Science.gov (United States)

Janssen, Tracy; Carton, John S

1999-12-01

The authors investigated the effects of locus of control expectancies and task difficulty on procrastination. Forty-two college students were administered an academic locus of control scale and a task that was similar to a typical college homework assignment. The students were randomly assigned to 1 of 2 task difficulty levels. Although none of the results involving task difficulty was significant, several results involving locus of control were significant. Specifically, analyses revealed that students with internal locus of control expectancies tended to begin working on the assignment sooner than students with external locus of control expectancies. In addition, students with internal locus of control completed and returned the assignment sooner than students with external locus of control. The results are discussed within the context of J. B. Rotter's (1966, 1975, 1982) social learning theory.

Technical requirements on knowledge base and instrumentation system for decision making in plant operation and maintenance

International Nuclear Information System (INIS)

Kitamura, Masaharu; Yoshikawa, Shinji; Hasegawa, Makoto

1998-03-01

A series of technical surveys and studies are described in this report to examine and identify technical requirements to be posed on knowledge base and instrumentation system as the fundamental in high reliability computational decision making in operation and maintenance of nuclear power plants. Monitoring and diagnosis are focused as the important tasks among the operation/maintenance-related tasks. A concrete monitoring and diagnosis system configuration has been proposed consisting of distributed symptom database and of on-demand measurement subsystem. An prototype of the proposed system configuration has been successfully verified. (author)

Remote maintenance lessons learned on prototypical reprocessing equipment

International Nuclear Information System (INIS)

Kring, C.T.; Schrock, S.L.

1990-01-01

A major objective of the Consolidated Fuel Reprocessing Program at the Oak Ridge National Laboratory is to develop and demonstrate the technology required to reprocess spent nuclear fuel. The Fuel Recycle Division, over the past 16 years, has undertaken this objective by designing and testing prototypical hardware representing essentially every major equipment item currently included in most fuel reprocessing plant conceptual designs. These designs are based on total remote maintenance to increase plant availability and reduce radiation exposure to plant operators. The designs include modular equipment to facilitate maintainability and the remote manipulation necessary to accomplish maintenance tasks. Prototypic equipment has been installed and tested in a cold mock-up of a reprocessing hot cell, called the remote operations and maintenance demonstration facility. The applied maintenance concept utilizes the dexterity and mobility of bridge-mounted, force-reflecting servomanipulators. Prototypic processing equipment includes a remote disassembly system, a remote shear system, a rotary dissolver, a remote automated sampler system, removable equipment racks to support chemical process equipment items, and the advanced servomanipulators. Each of these systems and a brief description of functions are discussed

Visual-Spatial Attention Aids the Maintenance of Object Representations in Visual Working Memory

Science.gov (United States)

Williams, Melonie; Pouget, Pierre; Boucher, Leanne; Woodman, Geoffrey F.

2013-01-01

Theories have proposed that the maintenance of object representations in visual working memory is aided by a spatial rehearsal mechanism. In this study, we used two different approaches to test the hypothesis that overt and covert visual-spatial attention mechanisms contribute to the maintenance of object representations in visual working memory. First, we tracked observers’ eye movements while remembering a variable number of objects during change-detection tasks. We observed that during the blank retention interval, participants spontaneously shifted gaze to the locations that the objects had occupied in the memory array. Next, we hypothesized that if attention mechanisms contribute to the maintenance of object representations, then drawing attention away from the object locations during the retention interval would impair object memory during these change-detection tasks. Supporting this prediction, we found that attending to the fixation point in anticipation of a brief probe stimulus during the retention interval reduced change-detection accuracy even on the trials in which no probe occurred. These findings support models of working memory in which visual-spatial selection mechanisms contribute to the maintenance of object representations. PMID:23371773

Study to determine the reliability and validity of a needs-assessment instrument used within the mechanical maintenance field of the nuclear electrical-generating industry

International Nuclear Information System (INIS)

Russell, L.O.

1982-01-01

This study was to determine if task parameter ratings provided by nuclear power plant maintenance mechanics assessed the true task frequency, criticality, and difficulty. This was to measure the data's usefulness as a training needs assessment indicator. A questionnaire entitled Job Task Questionnaire for Maintenance Mechanics was developed and used to collect data from job incumbents. Development was based on plant visits and incumbent interviews. Duties, tasks, parameters, and scales were then compiled to form the questionnaire. The questionnaire was then pilot tested. A random sample was selected from the national population of nuclear power plant maintenance mechanics. This resulted in a sample which was stratified across the job title and random within the job title. The descriptive analysis did not tend to indicate that the mean value of each task parameter provided a true or valid value. The overall conclusion drawn from the data analysis was that the ratings did not provide a substantially valid or reliable indication on which to base task training needs

Internalizing versus Externalizing Control: Different Ways to Perform a Time-Based Prospective Memory Task

Science.gov (United States)

Huang, Tracy; Loft, Shayne; Humphreys, Michael S.

2014-01-01

"Time-based prospective memory" (PM) refers to performing intended actions at a future time. Participants with time-based PM tasks can be slower to perform ongoing tasks (costs) than participants without PM tasks because internal control is required to maintain the PM intention or to make prospective-timing estimates. However, external…

Improvement of the preventive maintenance program of an emergency diesel generator set

International Nuclear Information System (INIS)

Jacquot, J.P.; Meuwisse, C.; Cailleaux, J.P.

1995-01-01

An exhaustive Reliability Centered Maintenance (RCM) analysis was performed of the emergency diesel generator sets in Electricite de France 900-MW nuclear power plants. The first part of this paper describes the Reliability Centered Maintenance approach, including the functional breakdown, complete analysis of operation feedback and safety assessment of the risk induced by functional diesel failures. The second part shows how this kind of RCM analysis can be used to improve the efficiency of periodic tests of the machine, and more generally, the efficiency of condition-directed maintenance tasks. The underlying objective is to minimize risk and aging of the machine

Age-related changes of frontal-midline theta is predictive of efficient memory maintenance.

Science.gov (United States)

Kardos, Z; Tóth, B; Boha, R; File, B; Molnár, M

2014-07-25

Frontal areas are thought to be the coordinators of working memory processes by controlling other brain areas reflected by oscillatory activities like frontal-midline theta (4-7 Hz). With aging substantial changes can be observed in the frontal brain areas, presumably leading to age-associated changes in cortical correlates of cognitive functioning. The present study aimed to test whether altered frontal-midline theta dynamics during working memory maintenance may underlie the capacity deficits observed in older adults. 33-channel EEG was recorded in young (18-26 years, N=20) and old (60-71 years, N=16) adults during the retention period of a visual delayed match-to-sample task, in which they had to maintain arrays of 3 or 5 colored squares. An additional visual odd-ball task was used to be able to measure the electrophysiological indices of sustained attentional processes. Old participants showed reduced frontal theta activity during both tasks compared to the young group. In the young memory maintenance-related frontal-midline theta activity was shown to be sensitive both to the increased memory demands and to efficient subsequent memory performance, whereas the old adults showed no such task-related difference in the frontal theta activity. The decrease of frontal-midline theta activity in the old group indicates that cerebral aging may alter the cortical circuitries of theta dynamics, thereby leading to age-associated decline of working memory maintenance function. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Assessing Biobehavioural Self-Regulation and Coregulation in Early Childhood: The Parent-Child Challenge Task.

Science.gov (United States)

Lunkenheimer, Erika; Kemp, Christine J; Lucas-Thompson, Rachel G; Cole, Pamela M; Albrecht, Erin C

2017-01-01

Researchers have argued for more dynamic and contextually relevant measures of regulatory processes in interpersonal interactions. In response, we introduce and examine the effectiveness of a new task, the Parent-Child Challenge Task, designed to assess the self-regulation and coregulation of affect, goal-directed behavior, and physiology in parents and their preschoolers in response to an experimental perturbation. Concurrent and predictive validity was examined via relations with children's externalizing behaviors. Mothers used only their words to guide their 3-year-old children to complete increasingly difficult puzzles in order to win a prize ( N = 96). A challenge condition was initiated mid-way through the task with a newly introduced time limit. The challenge produced decreases in parental teaching and dyadic behavioral variability and increases in child negative affect and dyadic affective variability, measured by dynamic systems-based methods. Children rated lower on externalizing showed respiratory sinus arrhythmia (RSA) suppression in response to challenge, whereas those rated higher on externalizing showed RSA augmentation. Additionally, select task changes in affect, behavior, and physiology predicted teacher-rated externalizing behaviors four months later. Findings indicate the Parent-Child Challenge Task was effective in producing regulatory changes and suggest its utility in assessing biobehavioral self-regulation and coregulation in parents and their preschoolers.

Dataset Documentation for the ERTMS-Oriented Signalling Maintenance in the Danish Railway System

DEFF Research Database (Denmark)

M. Pour, Shahrzad

2017-01-01

This documentation provides information about the dataset generated as part of a PhD thesis (Towards Signalling Maintenance Scheduling Problem for European Railway Traffic Management System ) for the signaling maintenance of the Danish railway system . The data instances (M.Pour 2018a; M.Pour 2018b......) have been created for the purpose of adaptation to the newest railway signalling standard which is so called European Railway Traffic Management System(ERTMS). The chapter provides explanation of the different types of maintenance tasks in the ERTMS, followed by data definition. Furthermore...

ITER L 6 equatorial maintenance duct remote handling study

International Nuclear Information System (INIS)

Millard, J.

1996-09-01

The status and conclusions of a preliminary study of equatorial maintenance duct remote handling is reported. Due to issues with the original duct design a significant portion of the study had to be refocused on equatorial duct layout studies. The study gives an overview of some of the options for design of these ducts and the impact of the design on the equipment to work in the duct. To develop a remote handling concept for creating access through the ducts the following design tasks should be performed: define the operations sequences for equatorial maintenance duct opening and closing; review the remote handling requirements for equatorial maintenance duct opening and closing; design concept for door and pipe handling equipment and to propose preliminary procedures for material handling outsides the duct. 35 figs

Influence of visual feedback on human task performance in ITER remote handling

Energy Technology Data Exchange (ETDEWEB)

Schropp, Gwendolijn Y.R., E-mail: g.schropp@heemskerk-innovative.nl [Utrecht University, Utrecht (Netherlands); Heemskerk Innovative Technology, Noordwijk (Netherlands); Heemskerk, Cock J.M. [Heemskerk Innovative Technology, Noordwijk (Netherlands); Kappers, Astrid M.L.; Tiest, Wouter M. Bergmann [Helmholtz Institute-Utrecht University, Utrecht (Netherlands); Elzendoorn, Ben S.Q. [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM/FOM, Partner in the Trilateral Euregio Clusterand ITER-NL, PO box 1207, 3430 BE Nieuwegein (Netherlands); Bult, David [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM/FOM, Partner in the Trilateral Euregio Clusterand ITER-NL, PO box 1207, 3430 BE Nieuwegein (Netherlands)

2012-08-15

Highlights: Black-Right-Pointing-Pointer The performance of human operators in an ITER-like test facility for remote handling. Black-Right-Pointing-Pointer Different sources of visual feedback influence how fast one can complete a maintenance task. Black-Right-Pointing-Pointer Insights learned could be used in design of operator work environment or training procedures. - Abstract: In ITER, maintenance operations will be largely performed by remote handling (RH). Before ITER can be put into operation, safety regulations and licensing authorities require proof of maintainability for critical components. Part of the proof will come from using standard components and procedures. Additional verification and validation is based on simulation and hardware tests in 1:1 scale mockups. The Master Slave manipulator system (MS2) Benchmark Product was designed to implement a reference set of maintenance tasks representative for ITER remote handling. Experiments were performed with two versions of the Benchmark Product. In both experiments, the quality of visual feedback varied by exchanging direct view with indirect view (using video cameras) in order to measure and analyze its impact on human task performance. The first experiment showed that both experienced and novice RH operators perform a simple task significantly better with direct visual feedback than with camera feedback. A more complex task showed a large variation in results and could not be completed by many novice operators. Experienced operators commented on both the mechanical design and visual feedback. In a second experiment, a more elaborate task was tested on an improved Benchmark product. Again, the task was performed significantly faster with direct visual feedback than with camera feedback. In post-test interviews, operators indicated that they regarded the lack of 3D perception as the primary factor hindering their performance.

Influence of visual feedback on human task performance in ITER remote handling

International Nuclear Information System (INIS)

Schropp, Gwendolijn Y.R.; Heemskerk, Cock J.M.; Kappers, Astrid M.L.; Tiest, Wouter M. Bergmann; Elzendoorn, Ben S.Q.; Bult, David

2012-01-01

Highlights: ► The performance of human operators in an ITER-like test facility for remote handling. ► Different sources of visual feedback influence how fast one can complete a maintenance task. ► Insights learned could be used in design of operator work environment or training procedures. - Abstract: In ITER, maintenance operations will be largely performed by remote handling (RH). Before ITER can be put into operation, safety regulations and licensing authorities require proof of maintainability for critical components. Part of the proof will come from using standard components and procedures. Additional verification and validation is based on simulation and hardware tests in 1:1 scale mockups. The Master Slave manipulator system (MS2) Benchmark Product was designed to implement a reference set of maintenance tasks representative for ITER remote handling. Experiments were performed with two versions of the Benchmark Product. In both experiments, the quality of visual feedback varied by exchanging direct view with indirect view (using video cameras) in order to measure and analyze its impact on human task performance. The first experiment showed that both experienced and novice RH operators perform a simple task significantly better with direct visual feedback than with camera feedback. A more complex task showed a large variation in results and could not be completed by many novice operators. Experienced operators commented on both the mechanical design and visual feedback. In a second experiment, a more elaborate task was tested on an improved Benchmark product. Again, the task was performed significantly faster with direct visual feedback than with camera feedback. In post-test interviews, operators indicated that they regarded the lack of 3D perception as the primary factor hindering their performance.

Maintenance personnel performance simulation (MAPPS): a model for predicting maintenance performance reliability in nuclear power plants

International Nuclear Information System (INIS)

Knee, H.E.; Krois, P.A.; Haas, P.M.; Siegel, A.I.; Ryan, T.G.

1983-01-01

The NRC has developed a structured, quantitative, predictive methodology in the form of a computerized simulation model for assessing maintainer task performance. Objective of the overall program is to develop, validate, and disseminate a practical, useful, and acceptable methodology for the quantitative assessment of NPP maintenance personnel reliability. The program was organized into four phases: (1) scoping study, (2) model development, (3) model evaluation, and (4) model dissemination. The program is currently nearing completion of Phase 2 - Model Development

The TFTR maintenance manipulator

International Nuclear Information System (INIS)

Kungl, D.; Loesser, D.; Heitzenroeder, P.; Cerdan, G.

1989-01-01

TFTR plans to begin D-T experiments in mid 1990. The D-T experimental program will produce approximately one hundred shots, with a neutron generation rate of 10 19 neutrons per shot. This will result in high levels of activation in TFTR, especially in the vacuum vessel. The primary purpose of the Maintenance Manipulator is to provide a means of remotely performing certain defined maintenance and inspection tasks inside the vacuum torus so as to minimize personnel exposure to radiation. The manipulator consists of a six-link folding boom connected to a fixed boom on a movable carriage. The entire manipulator is housed in a vacuum antechamber connected to the vacuum torus, through a port formerly used for a vacuum pumping duct. The configuration extends 180 0 in either direction to provide complete coverage of the torus. The four 3500 l/s turbopumps which were formerly used in the pumping duct will be mounted on the antechamber. The manipulator will utilize two end effectors. The first, called a General Inspection Arm (GIA) provides a movable platform to an inspection camera and an in-vacuum leak detector. The second is a bilateral, force-reflecting pair of slave arms which utilize specially developed tools to perform several maintenance functions. All components except the slave arms are capable of operating in TFTR's vacuum environment and during 150 0 C bakeout of the torus. (orig.)

On the application of copula in modeling maintenance contract

International Nuclear Information System (INIS)

Iskandar, B P; Husniah, H

2016-01-01

This paper deals with the application of copula in maintenance contracts for a nonrepayable item. Failures of the item are modeled using a two dimensional approach where age and usage of the item and this requires a bi-variate distribution to modelling failures. When the item fails then corrective maintenance (CM) is minimally repaired. CM can be outsourced to an external agent or done in house. The decision problem for the owner is to find the maximum total profit whilst for the agent is to determine the optimal price of the contract. We obtain the mathematical models of the decision problems for the owner as well as the agent using a Nash game theory formulation. (paper)

External event analysis methods for NUREG-1150

International Nuclear Information System (INIS)

Bohn, M.P.; Lambright, J.A.

1989-01-01

The US Nuclear Regulatory Commission is sponsoring probabilistic risk assessments of six operating commercial nuclear power plants as part of a major update of the understanding of risk as provided by the original WASH-1400 risk assessments. In contrast to the WASH-1400 studies, at least two of the NUREG-1150 risk assessments will include an analysis of risks due to earthquakes, fires, floods, etc., which are collectively known as eternal events. This paper summarizes the methods to be used in the external event analysis for NUREG-1150 and the results obtained to date. The two plants for which external events are being considered are Surry and Peach Bottom, a PWR and BWR respectively. The external event analyses (through core damage frequency calculations) were completed in June 1989, with final documentation available in September. In contrast to most past external event analyses, wherein rudimentary systems models were developed reflecting each external event under consideration, the simplified NUREG-1150 analyses are based on the availability of the full internal event PRA systems models (event trees and fault trees) and make use of extensive computer-aided screening to reduce them to sequence cut sets important to each external event. This provides two major advantages in that consistency and scrutability with respect to the internal event analysis is achieved, and the full gamut of random and test/maintenance unavailabilities are automatically included, while only those probabilistically important survive the screening process. Thus, full benefit of the internal event analysis is obtained by performing the internal and external event analyses sequentially

Mobile robotics for CANDU maintenance

International Nuclear Information System (INIS)

Lipsett, M.G.; Rody, K.H.

1996-01-01

Although robotics researchers have been promising that robotics would soon be performing tasks in hazardous environments, the reality has yet to live up to the hype. The presently available crop of robots suitable for deployment in industrial situations are remotely operated, requiring skilled users. This talk describes cases where mobile robots have been used successfully in CANDU stations, discusses the difficulties in using mobile robots for reactor maintenance, and provides near-term goals for achievable improvements in performance and usefulness. (author) 5 refs., 2 ills

Reliability Centered Maintenance (RCM) Methodology and Application to the Shutdown Cooling System for APR-1400 Reactors

Energy Technology Data Exchange (ETDEWEB)

Faragalla, Mohamed M.; Emmanuel, Efenji; Alhammadi, Ibrahim; Awwal, Arigi M.; Lee, Yong Kwan [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

2016-10-15

Shutdown Cooling System (SCS) is a safety-related system that is used in conjunction with the Main Steam and Main or Auxiliary Feedwater Systems to reduce the temperature of the Reactor Coolant System (RCS) in post shutdown periods from the hot shutdown operating temperature to the refueling temperature. In this paper RCM methodology is applied to (SCS). RCM analysis is performed based on evaluation of Failure Modes Effects and Criticality Analysis (FME and CA) on the component, system and plant. The Logic Tree Analysis (LTA) is used to determine the optimum maintenance tasks. The main objectives of RCM is the safety, preserve the System function, the cost-effective maintenance of the plant components and increase the reliability and availability value. The RCM methodology is useful for improving the equipment reliability by strengthening the management of equipment condition, and leads to a significant decrease in the number of periodical maintenance, extended maintenance cycle, longer useful life of equipment, and decrease in overall maintenance cost. It also focuses on the safety of the system by assigning criticality index to the various components and further selecting maintenance activities based on the risk of failure involved. Therefore, it can be said that RCM introduces a maintenance plan designed for maximum safety in an economical manner and making the system more reliable. For the SCP, increasing the number of condition monitoring tasks will improve the availability of the SCP. It is recommended to reduce the number of periodic maintenance activities.

Present status of the Nuclear Maintenance Training Center

International Nuclear Information System (INIS)

Kotani, Fumio

1995-01-01

The education and training to keep and improve the knowledge and skills of the maintenance personnel and to hand down the skills undoubtedly play important roles in safe operation and increased reliability to a nuclear power station. The Nuclear Maintenance Training Center (hereafter called the Center) provides a variety of education and training curriculums based on the levels and abilities of the trainees. The Center aims to enhance the personnel's maintenance technique by offering the curriculums on maintenance basic education for operators and supporting education and training for the personnel of contractors. The Center has two main features: first, it has the actual components or the equipment similar to the actual components which will enable the practical training; second, we regard the past troubles as valuable experiences and, therefore, focuses on the education to prevent recurrence of troubles by teaching the trainees the meaning and necessity of the training they take. For eleven years since the establishment of the Center, it has been utilized by the total number of about 60,000 people. As for the tasks in the future, the Center is expected to vitalize itself to give attractive education and training and become more actively involved in development of the maintenance personnel with the adequate knowledge and skills. (author)

Key Performance Indicators for Maintenance Management Effectiveness of Public Hospital Building

Directory of Open Access Journals (Sweden)

Farhana Omar Mardhiah

2017-01-01

Full Text Available Effectiveness of management in maintenance aspect holds the key element in influencing the performance of overall maintenance management. Similarly, public hospital building needs an effective maintenance management as this type of building in nature is one of the most complex issues in the field of maintenance. Improper building maintenance management adopted by the organization significantly will interrupt the overall operation of the building. Therefore, this paper is aim to identifying the key performance indicator (KPI of effectiveness of maintenance management for the public hospital building. A total of 32 set of questionnaires were distributed to the maintenance manager for each hospital in the northern region of peninsular Malaysia by using self-administration strategy. The survey answer was analyzed by performing descriptive analysis in SPSS. Overall, the result of descriptive analysis shows that all the ten factors of effectiveness of maintenance management are accepted as KPI since the mean value is at least 3.93 which classified as important and significant. The most significant factor of effectiveness of maintenance management is task planning and scheduling with the mean score of 4.35. While less significant factor is identify as maintenance approach with the value of mean score is 3.93. The both results indicates that the management need to have well-structured planning for the maintenance works and also need to embrace the exact strategy of maintenance approach in order to achieved better overall performance of maintenance management. This study may draw a standard practice for the government in assessing the performance of public facilities in terms of maintenance management.

Preventive maintenance and reliability-centered maintenance

International Nuclear Information System (INIS)

Anderson, J.G.

1989-01-01

In the recent past, the primary function of the preventive maintenance program at a nuclear power plant was to maintain the operability and reliability of the plant. Reducing overall maintenance costs by performing effective preventive maintenance, instead of more costly and disruptive corrective maintenance, instead of more costly and disruptive corrective maintenance, was a secondary consideration. In today's operating environment, the preventive maintenance program must meet the test of cost-effectiveness as well as many new standards for performance that are being required by rate regulators. The preventive maintenance program must be able to withstand the challenge of independent audit to a new standard of technical adequacy and compliance with recommendations from component vendors. In this new environment, the standard that is being applied at the San Onofre nuclear generating station (SONGS) is that the preventive maintenance program must meet the test of cost-effectiveness, improve equipment performance, support increased plant availability, and (a) literally implement the recommendations of the vendor, (b) provide other compensation for the vendor recommendation, or (c) provide technical justification for the deviation. The subject of this paper is the way that reliability-centered maintenance (RCM) is helping SONGS meet these challenges

Extending Virtual Reality simulation of ITER maintenance operations with dynamic effects

International Nuclear Information System (INIS)

Heemskerk, C.J.M.; Baar, M.R. de; Boessenkool, H.; Graafland, B.; Haye, M.J.; Koning, J.F.; Vahedi, M.; Visser, M.

2011-01-01

Virtual Reality (VR) simulation can be used to study, improve and verify ITER maintenance operations during preparation. VR can also improve the situational awareness of human operators during actual Remote Handling (RH) operations. Until now, VR systems use geometric models of the environment and the objects being handled and kinematic models of the manipulation systems. The addition of dynamic effects into the VR simulation was investigated. Important dynamic effects are forces due to contact transitions and the bending of beams under heavy loads. A novel dynamics simulation module was developed and introduced as an add-on to the VR4Robots VR software. Tests were performed under simplified test conditions and in the context of realistic ITER maintenance tasks on a benchmark product and on the ECRH Upper Port Launcher Plug (UPL). The introduction of dynamic effects into VR simulations was found to add realism and provide new insights in procedure development. The quality of the haptic feedback depends strongly on the haptic device used to 'display' haptic feedback to the operator. Dynamic effect simulation can also form the basis for real-time guidance support to operators during the execution of maintenance tasks (augmented reality).

Distinct electrophysiological indices of maintenance in auditory and visual short-term memory.

Science.gov (United States)

Lefebvre, Christine; Vachon, François; Grimault, Stephan; Thibault, Jennifer; Guimond, Synthia; Peretz, Isabelle; Zatorre, Robert J; Jolicœur, Pierre

2013-11-01

We compared the electrophysiological correlates for the maintenance of non-musical tones sequences in auditory short-term memory (ASTM) to those for the short-term maintenance of sequences of coloured disks held in visual short-term memory (VSTM). The visual stimuli yielded a sustained posterior contralateral negativity (SPCN), suggesting that the maintenance of sequences of coloured stimuli engaged structures similar to those involved in the maintenance of simultaneous visual displays. On the other hand, maintenance of acoustic sequences produced a sustained negativity at fronto-central sites. This component is named the Sustained Anterior Negativity (SAN). The amplitude of the SAN increased with increasing load in ASTM and predicted individual differences in the performance. There was no SAN in a control condition with the same auditory stimuli but no memory task, nor one associated with visual memory. These results suggest that the SAN is an index of brain activity related to the maintenance of representations in ASTM that is distinct from the maintenance of representations in VSTM. © 2013 Elsevier Ltd. All rights reserved.

Inducing task-relevant responses to speech in the sleeping brain.

Science.gov (United States)

Kouider, Sid; Andrillon, Thomas; Barbosa, Leonardo S; Goupil, Louise; Bekinschtein, Tristan A

2014-09-22

Falling asleep leads to a loss of sensory awareness and to the inability to interact with the environment [1]. While this was traditionally thought as a consequence of the brain shutting down to external inputs, it is now acknowledged that incoming stimuli can still be processed, at least to some extent, during sleep [2]. For instance, sleeping participants can create novel sensory associations between tones and odors [3] or reactivate existing semantic associations, as evidenced by event-related potentials [4-7]. Yet, the extent to which the brain continues to process external stimuli remains largely unknown. In particular, it remains unclear whether sensory information can be processed in a flexible and task-dependent manner by the sleeping brain, all the way up to the preparation of relevant actions. Here, using semantic categorization and lexical decision tasks, we studied task-relevant responses triggered by spoken stimuli in the sleeping brain. Awake participants classified words as either animals or objects (experiment 1) or as either words or pseudowords (experiment 2) by pressing a button with their right or left hand, while transitioning toward sleep. The lateralized readiness potential (LRP), an electrophysiological index of response preparation, revealed that task-specific preparatory responses are preserved during sleep. These findings demonstrate that despite the absence of awareness and behavioral responsiveness, sleepers can still extract task-relevant information from external stimuli and covertly prepare for appropriate motor responses. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Co-morbid pain and opioid addiction: long term effect of opioid maintenance on acute pain.

Science.gov (United States)

Wachholtz, Amy; Gonzalez, Gerardo

2014-12-01

Medication assisted treatment for opioid dependence alters the pain experience. This study will evaluate changes pain sensitivity and tolerance with opioid treatments; and duration of this effect after treatment cessation. 120 Individuals with chronic pain were recruited in 4 groups (N = 30): 1-methadone for opioid addiction; 2-buprenorphine for opioid addiction; 3-history of opioid maintenance treatment for opioid addiction but with prolonged abstinence (M = 121 weeks; SD = 23.3); and 4-opioid naïve controls. Participants completed a psychological assessment and a cold water task including, time to first pain (sensitivity) and time to stopping the pain task (tolerance). Data analysis used survival analyses. A Kaplan-Meier-Cox survival analysis showed group differences for both pain sensitivity (log rank = 15.50; p opioid maintenance resulted in differing pain sensitivity compared to opioid naïve (p's opioid maintenance compared to active methadone patients (p opioid naïve control group participants (p's opioid abstinence increased (R = .37; p opioid maintenance, there appears to be long-term differences in pain sensitivity that do not resolve with discontinuation of opioid maintenance. Although pain sensitivity does not change, pain tolerance does improve after opioid maintenance cessation. Implications for treating co-morbid opioid addiction and pain (acute and chronic) are discussed. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Task control signals in pediatric Tourette syndrome show evidence of immature and anomalous functional activity

Directory of Open Access Journals (Sweden)

Jessica A Church

2009-11-01

Full Text Available Tourette Syndrome (TS is a pediatric movement disorder that may affect control signaling in the brain. Previous work has proposed a dual-networks architecture of control processing involving a task-maintenance network and an adaptive control network (Dosenbach et al., 2008. A prior resting-state functional connectivity MRI (rs-fcMRI analysis in TS has revealed functional immaturity in both putative control networks, with “anomalous” correlations (i.e. correlations outside the typical developmental range limited to the adaptive control network (Church et al., 2009. The present study used functional MRI (fMRI to study brain activity related to adaptive control (by studying start-cues signals, and to task-maintenance (by studying signals sustained across a task set. Two hypotheses from the previous rs-fcMRI results were tested. First, adaptive control (i.e., start-cue activity will be altered in TS, including activity inconsistent with typical development (“anomalous”. Second, group differences found in task maintenance (i.e., sustained activity will be consistent with functional immaturity in TS. We examined regions found through a direct comparison of adolescents with and without TS, as well as regions derived from a previous investigation that showed differences between unaffected children and adults. The TS group showed decreased start-cue signal magnitude in regions where start-cue activity is unchanged over typical development, consistent with anomalous adaptive control. The TS group also had higher magnitude sustained signals in frontal cortex regions that overlapped with regions showing differences over typical development, consistent with immature task maintenance in TS. The results demonstrate task-related fMRI signal differences anticipated by the atypical functional connectivity found previously in adolescents with TS, strengthening the evidence for functional immaturity and anomalous signaling in control networks in adolescents

Opportune maintenance and predictive maintenance decision support

OpenAIRE

Thomas , Edouard; Levrat , Eric; Iung , Benoît; Cocheteux , Pierre

2009-01-01

International audience; Conventional maintenance strategies on a single component are being phased out in favour of more predictive maintenance actions. These new kinds of actions are performed in order to control the global performances of the whole industrial system. They are anticipative in nature, which allows a maintenance expert to consider non-already-planned maintenance actions. Two questions naturally emerge: when to perform a predictive maintenance action; how a maintenance expert c...

Maintenance program, organization and procedures

International Nuclear Information System (INIS)

Schegk, J.R.R.

1986-01-01

The Rheinisch-Westfaelisches Elektrizitaetswerk AG (RWE) operates two pressurized water reactors (PWR) with 1.200 MW and 1.300 MW and two boiling water reactors (BWR) with an electrical output of 1.300 MW each. The PWR were commissioned in 1975 and 1977 respectively and have so far achieved a cumulative availability of 72%. The BWR started operating in 1984 and 1985. Since than they have been generating with a cumulative availability of 88%. The reliability of the nuclear power stations resulted in a trouble-free operation. For the last two years, the unscheduled non-availability amounted to 3,7% and 6,5% for the PWR and the BWR respectively. These favourable operating results derive inter alia from systematic preventive maintenance and consistent outage management. Apart from the personnel structure in the power stations the functional sequence of planning, control, performance as well as evaluation of maintenance results constitute a closed cycle. In order to ensure and support an effective cooperation of the above mentioned four functional sequences of a cycle, uniform and computer-assisted information and planning aids have been introduced such as task lists, job ordering, time scheduling and materials management. As a result of this preventive maintenance system the average refueling outage period is 35 to 42 days. (orig.)

Modeling and simulation of maintenance treatment in first-line non-small cell lung cancer with external validation

International Nuclear Information System (INIS)

Han, Kelong; Claret, Laurent; Sandler, Alan; Das, Asha; Jin, Jin; Bruno, Rene

2016-01-01

Maintenance treatment (MTx) in responders following first-line treatment has been investigated and practiced for many cancers. Modeling and simulation may support interpretation of interim data and development decisions. We aimed to develop a modeling framework to simulate overall survival (OS) for MTx in NSCLC using tumor growth inhibition (TGI) data. TGI metrics were estimated using longitudinal tumor size data from two Phase III first-line NSCLC studies evaluating bevacizumab and erlotinib as MTx in 1632 patients. Baseline prognostic factors and TGI metric estimates were assessed in multivariate parametric models to predict OS. The OS model was externally validated by simulating a third independent NSCLC study (n = 253) based on interim TGI data (up to progression-free survival database lock). The third study evaluated pemetrexed + bevacizumab vs. bevacizumab alone as MTx. Time-to-tumor-growth (TTG) was the best TGI metric to predict OS. TTG, baseline tumor size, ECOG score, Asian ethnicity, age, and gender were significant covariates in the final OS model. The OS model was qualified by simulating OS distributions and hazard ratios (HR) in the two studies used for model-building. Simulations of the third independent study based on interim TGI data showed that pemetrexed + bevacizumab MTx was unlikely to significantly prolong OS vs. bevacizumab alone given the current sample size (predicted HR: 0.81; 95 % prediction interval: 0.59–1.09). Predicted median OS was 17.3 months and 14.7 months in both arms, respectively. These simulations are consistent with the results of the final OS analysis published 2 years later (observed HR: 0.87; 95 % confidence interval: 0.63–1.21). Final observed median OS was 17.1 months and 13.2 months in both arms, respectively, consistent with our predictions. A robust TGI-OS model was developed for MTx in NSCLC. TTG captures treatment effect. The model successfully predicted the OS outcomes of an independent study based on interim

Modeling and simulation of maintenance treatment in first-line non-small cell lung cancer with external validation.

Science.gov (United States)

Han, Kelong; Claret, Laurent; Sandler, Alan; Das, Asha; Jin, Jin; Bruno, Rene

2016-07-13

Maintenance treatment (MTx) in responders following first-line treatment has been investigated and practiced for many cancers. Modeling and simulation may support interpretation of interim data and development decisions. We aimed to develop a modeling framework to simulate overall survival (OS) for MTx in NSCLC using tumor growth inhibition (TGI) data. TGI metrics were estimated using longitudinal tumor size data from two Phase III first-line NSCLC studies evaluating bevacizumab and erlotinib as MTx in 1632 patients. Baseline prognostic factors and TGI metric estimates were assessed in multivariate parametric models to predict OS. The OS model was externally validated by simulating a third independent NSCLC study (n = 253) based on interim TGI data (up to progression-free survival database lock). The third study evaluated pemetrexed + bevacizumab vs. bevacizumab alone as MTx. Time-to-tumor-growth (TTG) was the best TGI metric to predict OS. TTG, baseline tumor size, ECOG score, Asian ethnicity, age, and gender were significant covariates in the final OS model. The OS model was qualified by simulating OS distributions and hazard ratios (HR) in the two studies used for model-building. Simulations of the third independent study based on interim TGI data showed that pemetrexed + bevacizumab MTx was unlikely to significantly prolong OS vs. bevacizumab alone given the current sample size (predicted HR: 0.81; 95 % prediction interval: 0.59-1.09). Predicted median OS was 17.3 months and 14.7 months in both arms, respectively. These simulations are consistent with the results of the final OS analysis published 2 years later (observed HR: 0.87; 95 % confidence interval: 0.63-1.21). Final observed median OS was 17.1 months and 13.2 months in both arms, respectively, consistent with our predictions. A robust TGI-OS model was developed for MTx in NSCLC. TTG captures treatment effect. The model successfully predicted the OS outcomes of an independent study

Scanning the business external environment for information: evidence from Greece

Directory of Open Access Journals (Sweden)

L. Kourteli

2005-01-01

Full Text Available Introduction. This paper examines the business external environment scanning theory for information in the context of Greece. Method. A questionnaire was developed to explore the relationships between general and task business environment, perceived uncertainty, scanning strategy, and sources of information with respect to type of environment, size and industry.The research was based on a sample of 144 private organizations operating in North Greece. Analysis. Data collected were analysed using SPSS. The statistical procedures of chi-squared homogeneity test, ANOVA, Duncan's test of homogeneity of means, and related samples t-test were followed for testing the hypotheses developed. Results. The results show that perceived uncertainty of the general and task business external environment factors depend on the type of the environment, size of organization, and industry where the organizations operate; organizations adapt their scanning strategy to the complexity of the environment; personal sources of information seem to be more important than impersonal sources; external sources of information are equally important with internal sources; and higher levels of environmental uncertainty are associated with higher levels of scanning the various sources. Conclusion. Business external environment scanning of information is influenced by the characteristics of the organizations themselves and by the characteristics of the external environment within which the organizations operate. The study contributes to both environmental scanning theory and has important messages for practitioners.

Preferential processing of task-irrelevant beloved-related information and task performance: Two event-related potential studies.

Science.gov (United States)

Langeslag, Sandra J E; van Strien, Jan W

2017-09-18

People who are in love have better attention for beloved-related information, but report having trouble focusing on other tasks, such as (home)work. So, romantic love can both improve and hurt cognition. Emotional information is preferentially processed, which improves task performance when the information is task-relevant, but hurts task performance when it is task-irrelevant. Because beloved-related information is highly emotional, the effects of romantic love on cognition may resemble these effects of emotion on cognition. We examined whether beloved-related information is preferentially processed even when it is task-irrelevant and whether this hurts task performance. In two event-related potential studies, participants who had recently fallen in love performed a visuospatial short-term memory task. Task-irrelevant beloved, friend, and stranger faces were presented during maintenance (Study 1), or encoding (Study 2). The Early Posterior Negativity (EPN) reflecting early automatic attentional capturing and the Late Positive Potential (LPP) reflecting sustained motivated attention were largest for beloved pictures. Thus, beloved pictures are preferentially processed even when they are task-irrelevant. Task performance and reaction times did not differ between beloved, friend, and stranger conditions. Nevertheless, self-reported obsessive thinking about the beloved tended to correlate negatively with task performance, and positively with reaction times, across conditions. So, although task-irrelevant beloved-related information does not impact task performance, more obsessive thinking about the beloved might relate to poorer and slower overall task performance. More research is needed to clarify why people experience trouble focusing on beloved-unrelated tasks and how this negative effect of love on cognition could be reduced. Copyright © 2017 Elsevier Ltd. All rights reserved.

Classifying Desirable Features of Software Visualization Tools for Corrective Maintenance

NARCIS (Netherlands)

Sensalire, Mariam; Ogao, Patrick; Telea, Alexandru

2008-01-01

We provide an evaluation of 15 software visualization tools applicable to corrective maintenance. The tasks supported as well as the techniques used are presented and graded based on the support level. By analyzing user acceptation of current tools, we aim to help developers to select what to

Maintenance of item and order information in verbal working memory.

Science.gov (United States)

Camos, Valérie; Lagner, Prune; Loaiza, Vanessa M

2017-09-01

Although verbal recall of item and order information is well-researched in short-term memory paradigms, there is relatively little research concerning item and order recall from working memory. The following study examined whether manipulating the opportunity for attentional refreshing and articulatory rehearsal in a complex span task differently affected the recall of item- and order-specific information of the memoranda. Five experiments varied the opportunity for articulatory rehearsal and attentional refreshing in a complex span task, but the type of recall was manipulated between experiments (item and order, order only, and item only recall). The results showed that impairing attentional refreshing and articulatory rehearsal similarly affected recall regardless of whether the scoring procedure (Experiments 1 and 4) or recall requirements (Experiments 2, 3, and 5) reflected item- or order-specific recall. This implies that both mechanisms sustain the maintenance of item and order information, and suggests that the common cumulative functioning of these two mechanisms to maintain items could be at the root of order maintenance.

Working memory maintenance is sufficient to reduce state anxiety.

Science.gov (United States)

Balderston, Nicholas L; Quispe-Escudero, David; Hale, Elizabeth; Davis, Andrew; O'Connell, Katherine; Ernst, Monique; Grillon, Christian

2016-11-01

According to the attentional control theory (ACT) proposed by Eysenck and colleagues, anxiety interferes with cognitive processing by prioritizing bottom-up attentional processes over top-down attentional processes, leading to competition for access to limited resources in working memory, particularly the central executive (Eysenck, Derakshan, Santos, & Calvo, ). However, previous research using the n-back working memory task suggests that working memory load also reduces state anxiety. Assuming that similar mechanisms underlie the effect of anxiety on cognition, and the effect of cognition on anxiety, one possible implication of the ACT would suggest that the reduction of state anxiety with increasing working memory load is driven by activation of central executive attentional control processes. We tested this hypothesis using the Sternberg working memory paradigm, where maintenance processes can be isolated from central executive processes (Altamura et al., ; Sternberg, ). Consistent with the n-back results, subjects showed decreased state anxiety during the maintenance period of high-load trials relative to low-load trials, suggesting that maintenance processes alone are sufficient to achieve this state anxiety reduction. Given that the Sternberg task does not require central executive engagement, these results are not consistent with an implication of the ACT where the cognition/anxiety relationship and anxiety/cognition relationship are mediated by similar central executive mechanisms. Instead, we propose an extension of the ACT such that engaging working memory maintenance suppresses state anxiety in a load-dependent manner. Furthermore, we hypothesize that the efficacy of this effect may moderate the effect of trait anxiety on cognition. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Task planning systems with natural language interface

International Nuclear Information System (INIS)

Kambayashi, Shaw; Uenaka, Junji

1989-12-01

In this report, a natural language analyzer and two different task planning systems are described. In 1988, we have introduced a Japanese language analyzer named CS-PARSER for the input interface of the task planning system in the Human Acts Simulation Program (HASP). For the purpose of a high speed analysis, we have modified a dictionary system of the CS-PARSER by using C language description. It is found that the new dictionary system is very useful for a high speed analysis and an efficient maintenance of the dictionary. For the study of the task planning problem, we have modified a story generating system named Micro TALE-SPIN to generate a story written in Japanese sentences. We have also constructed a planning system with natural language interface by using the CS-PARSER. Task planning processes and related knowledge bases of these systems are explained. A concept design for a new task planning system will be also discussed from evaluations of above mentioned systems. (author)

Operation and Maintenance Plan for the 300-FF-5 Operable Unit

International Nuclear Information System (INIS)

Singleton, K.M.

1996-09-01

This document is the operation and maintenance plan for the 300-FF-5 groundwater operable unit. The purpose of this plan is to identify tasks necessary to verify the effectiveness of the selected alternative. This plan also describes the monitoring program and administrative tasks that will be used as the preferred alternative for the remediation of groundwater in the 300-FF-5 Operable Unit. The preferred alternative selected for remediation of groundwater consists of institutional controls

Assessment for Learning Tasks and the Peer Assessment Process

Science.gov (United States)

Lauf, Lorraine; Dole, Shelley

2010-01-01

A program of Assessment for Learning (AfL) was implemented with 107 Year 12 students as part of their preparation for a major external test. Students completed extended mathematics tasks and selected student responses were used for peer assessment purposes. This paper reports on two of the AfL elements, namely task selection and peer assessment as…

Operationalizing Proneness to Externalizing Psychopathology as a Multivariate Psychophysiological Phenotype

Science.gov (United States)

Nelson, Lindsay D.; Patrick, Christopher J.; Bernat, Edward M.

2010-01-01

The externalizing dimension is viewed as a broad dispositional factor underlying risk for numerous disinhibitory disorders. Prior work has documented deficits in event-related brain potential (ERP) responses in individuals prone to externalizing problems. Here, we constructed a direct physiological index of externalizing vulnerability from three ERP indicators and evaluated its validity in relation to criterion measures in two distinct domains: psychometric and physiological. The index was derived from three ERP measures that covaried in their relations with externalizing proneness the error-related negativity and two variants of the P3. Scores on this ERP composite predicted psychometric criterion variables and accounted for externalizing-related variance in P3 response from a separate task. These findings illustrate how a diagnostic construct can be operationalized as a composite (multivariate) psychophysiological variable (phenotype). PMID:20573054

Ex-vessel remote maintenance design for the Compact Ignition Tokamak

International Nuclear Information System (INIS)

Spampinato, P.T.; Macdonald, D.

1987-01-01

The use of deuterium-tritium (D-T) fuel for operation of the Compact Ignition Tokamak (CIT) imposes a requirement for remote handling technology to carry out maintenance operations on auxiliary machine components. These operations consist of removing and repairing components such as diagnostics and radio frequency (rf) heating modules using remotely operated maintenance equipment. The major equipment that is being developed to accomplish maintenance external to the plasma chamber includes the bridge-mounted manipulator system for test cell operations, decontamination (decon) equipment, hot cell equipment, and solid rad-waste handling equipment. Wherever possible, the project will use commercially available equipment. Several areas of the maintenance system design have been addressed in fiscal year (FY) 1987. These included conceptual designs of manipulator systems, the start of a remote equipment research and development (R and D) program, and definition of the hot cell, decon, and equipment repair facility requirements. The manipulator work included investigating transporters and viewing/lighting subsystems. In each case, existing commercial units are being assessed initially, along with viable alternative approaches. R and D work also included demonstrations of remote handling operations on full-size, partial mock-ups of the CIT machine at the Oak Ridge National Laboratory (ORNL) Remote Operations and Maintenance Development Facility

Hybrid computing using a neural network with dynamic external memory.

Science.gov (United States)

Graves, Alex; Wayne, Greg; Reynolds, Malcolm; Harley, Tim; Danihelka, Ivo; Grabska-Barwińska, Agnieszka; Colmenarejo, Sergio Gómez; Grefenstette, Edward; Ramalho, Tiago; Agapiou, John; Badia, Adrià Puigdomènech; Hermann, Karl Moritz; Zwols, Yori; Ostrovski, Georg; Cain, Adam; King, Helen; Summerfield, Christopher; Blunsom, Phil; Kavukcuoglu, Koray; Hassabis, Demis

2016-10-27

Artificial neural networks are remarkably adept at sensory processing, sequence learning and reinforcement learning, but are limited in their ability to represent variables and data structures and to store data over long timescales, owing to the lack of an external memory. Here we introduce a machine learning model called a differentiable neural computer (DNC), which consists of a neural network that can read from and write to an external memory matrix, analogous to the random-access memory in a conventional computer. Like a conventional computer, it can use its memory to represent and manipulate complex data structures, but, like a neural network, it can learn to do so from data. When trained with supervised learning, we demonstrate that a DNC can successfully answer synthetic questions designed to emulate reasoning and inference problems in natural language. We show that it can learn tasks such as finding the shortest path between specified points and inferring the missing links in randomly generated graphs, and then generalize these tasks to specific graphs such as transport networks and family trees. When trained with reinforcement learning, a DNC can complete a moving blocks puzzle in which changing goals are specified by sequences of symbols. Taken together, our results demonstrate that DNCs have the capacity to solve complex, structured tasks that are inaccessible to neural networks without external read-write memory.

Maintenance Planning of Offshore Wind Turbine using Condition Monitoring Information

DEFF Research Database (Denmark)

Ramírez, José G. Rangel; Sørensen, John Dalsgaard

2009-01-01

Deterioration processes such as fatigue and corrosion are typically affecting offshore structures. To "control" this deterioration, inspection and maintenance activities are developed. Probabilistic methodologies represent an important tool to identify the suitable strategy to inspect and control...... the deterioration in structures such as offshore wind turbines (OWT). Besides these methods, the integration of condition monitoring information (CMI) can optimize the mitigation activities as an updating tool. In this paper, a framework for risk-based inspection and maintenance planning (RBI) is applied for OWT....... With the integration of CMI by means Bayesian inference, a slightly change of first inspection times are coming up, influenced by the reduction of the uncertainty and harsher or milder external agents....

Development of maintenance equipment for nuclear material fabrication equipment in a highly active hot cell

International Nuclear Information System (INIS)

Park, J. J.; Yang, M. S.; Kim, K. H. and others

2000-09-01

This report presents the development of a maintenance system for a highly contaminated nuclear material handling equipment at a hot-cell. This maintenance system has mainly three subsystems - a gamma-radiation measurement module for detecting a gamma-radiation level and identifying its distribution in-situ, a dry-type decontamination device for cleaning up contaminated particles, and a maintenance chamber for isolating contaminated equipment. The mechanical design considerations, controller, capabilities and remote operation and manipulation of the maintenance system are described. Such subsystems developed were installed and tested in the IMEF (Irradiated Material Examination Facility) M6 hot-cell after mock-up tests and performed their specific tasks successfully

Development of maintenance equipment for nuclear material fabrication equipment in a highly active hot cell

Energy Technology Data Exchange (ETDEWEB)

Park, J. J.; Yang, M. S.; Kim, K. H. and others

2000-09-01

This report presents the development of a maintenance system for a highly contaminated nuclear material handling equipment at a hot-cell. This maintenance system has mainly three subsystems - a gamma-radiation measurement module for detecting a gamma-radiation level and identifying its distribution in-situ, a dry-type decontamination device for cleaning up contaminated particles, and a maintenance chamber for isolating contaminated equipment. The mechanical design considerations, controller, capabilities and remote operation and manipulation of the maintenance system are described. Such subsystems developed were installed and tested in the IMEF (Irradiated Material Examination Facility) M6 hot-cell after mock-up tests and performed their specific tasks successfully.

Maintenance optimization and prognostics of residual life - A state of the art report

Energy Technology Data Exchange (ETDEWEB)

Nystad, Bent

2006-01-15

In many industries a huge part of the daily operational costs are related to maintenance. One key function in cutting costs is in optimization of the maintenance efforts. A major task is to change the work culture and work processes from being repair oriented, with focus on repairing breakdowns, to being proactive and maintain critical parts/systems before failures occur. Estimation of residual life distributions is of great need to obtain an optimum preventive maintenance strategy. In this report two approaches for estimation of residual life are discussed. The first model assumes that the residual life follows a Weibull distribution where the parameters are dependent on expert judgement, inspection data, repair data, and technical health trends. The second model is based on a continuous time Markov chain. In maintenance optimization a quantitative approach like the mean residual life estimation is needed in addition to a qualitative approach like the Reliability Centred Maintenance (RCM) methodology to give support for e.g. optimization of the maintenance overhaul intervals.The use of residual life knowledge in opportunistic maintenance is also discussed.(auth)

Externality costs by resource. E. Renewable generation resources

International Nuclear Information System (INIS)

Anon.

1991-01-01

This chapter describes the environmental impacts associated with operation of renewable energy technologies. Renewable energy technologies currently supply 8% of US total energy usage and that figure is certain to grow. The rate of growth will depend heavily on the availability of research and development funds, and could reach 28% of US energy demands by 2030. Renewable generation resources include hydroelectric development, solar energy technologies, wind conversion facilities, and biomass fueled generation. A task force of personnel from five national laboratories recently concluded that renewable energy technologies generally have lower environmental impacts than do fossil fuel energy systems. The task force also stated that a comprehensive and comparative analysis of environmental impacts is needed and would strengthen the National Energy Strategy. This chapter summarizes some of the available literature on costing the environmental externalities associated with hydro, solar, wind, and biomass facilities. The less prevalent renewable energy technologies, including geothermal and ocean energy technologies, were not researched. The cost ranges identified are summarized in Table 1. The Table does not include a value for hydroelectric energy. The one study which attempted to value hydroelectric externalities was highly site-specific and has been criticized for having vastly overstated the value of the externalities

Experience in the application of S.A.T. for maintenance training at Cernavoda N.P.P. - U1

International Nuclear Information System (INIS)

Erdinici, Abdula

1999-01-01

A short history of Maintenance Training at Cernavoda NPP Unit 1 will be presented highlighting the fact that: - Cernavoda NPP Unit 1 is the first nuclear power plant in Romania; - Construction/Commissioning and initial operation was done under the direct supervision of expert specialists (from Canada, Italy and US). In addition, the application of Systematic Approach to Training (S.A.T.) principles at Cernavoda NPP for all training activities will be addressed. A short history of how maintenance training activity developed over time will be detailed to address the following issues: - how the S.A.T. stages were applied; - how maintenance experience was gained during Unit 1 Construction/Commissioning initial operation and how this experience has been evaluated, credited and transferred; - how maintenance training was documented; - how the maintenance training activity is organized; - on-the-job training for maintenance personnel. Concerning other training activities at Cernavoda NPP the maintenance begins with a training needs analysis for each maintenance position. These needs are documented through Job Related Training requirements (JRTR's) produced for each maintenance position. During commissioning/initial operation, only necessary maintenance training has been delivered, such as: pump alignments, use of maintenance procedure, application of maintenance documentation. The 'hands-on' activities under expatriates specialists supervision was the main training activity. Training coordinators for each maintenance activity (Mechanical, EI. I-and-C, and Services maintenance) have been appointed to administer maintenance training. Following the declaration of the unit in commercial operation, a new approach has been taken related to maintenance Bucharest A Task Force to evaluate maintenance training status and experience has been established. This group was initiated at the Training Department initiative and it was initially co-ordinated by a Canadian maintenance

Functional Dissociation of Confident and Not-Confident Errors in the Spatial Delayed Response Task Demonstrates Impairments in Working Memory Encoding and Maintenance in Schizophrenia

Directory of Open Access Journals (Sweden)

Jutta S. Mayer

2018-05-01

Full Text Available Even though extensively investigated, the nature of working memory (WM deficits in patients with schizophrenia (PSZ is not yet fully understood. In particular, the contribution of different WM sub-processes to the severe WM deficit observed in PSZ is a matter of debate. So far, most research has focused on impaired WM maintenance. By analyzing different types of errors in a spatial delayed response task (DRT, we have recently demonstrated that incorrect yet confident responses (which we labeled as false memory errors rather than incorrect/not-confident responses reflect failures of WM encoding, which was also impaired in PSZ. In the present study, we provide further evidence for a functional dissociation between confident and not-confident errors by manipulating the demands on WM maintenance, i.e., the length over which information has to be maintained in WM. Furthermore, we investigate whether these functionally distinguishable WM processes are impaired in PSZ. Twenty-four PSZ and 24 demographically matched healthy controls (HC performed a spatial DRT in which the length of the delay period was varied between 1, 2, 4, and 6 s. In each trial, participants also rated their level of response confidence. Across both groups, longer delays led to increased rates of incorrect/not-confident responses, while incorrect/confident responses were not affected by delay length. This functional dissociation provides additional support for our proposal that false memory errors (i.e., confident errors reflect problems at the level of WM encoding, while not-confident errors reflect failures of WM maintenance. Schizophrenic patients showed increased numbers of both confident and not-confident errors, suggesting that both sub-processes of WM—encoding and maintenance—are impaired in schizophrenia. Combined with the delay length-dependent functional dissociation, we propose that these impairments in schizophrenic patients are functionally distinguishable.

Assessment of reliability and maintenance of motor operated valves at Finnish NPPS

International Nuclear Information System (INIS)

Laakso, K.; Haenninen, S.; Simola, K.

1994-01-01

This paper summarizes two studies on motor operated valve (MOV) failure and maintenance experiences in Finnish nuclear power plants. In the first study, described in section 2 of this paper, the failure reports of MOVs at Finnish BWR units from a nine years' time period were analyzed in a systematic way. The dominant failure mechanisms were identified and time-dependencies in failure occurrence were studied. This study initiated an experience based reliability centered maintenance (RCM) analysis of motor operated valve drives, which is summarized in chapter 3 of this paper. The RCM analysis resulted in the identification and proposal of the most suitable and effective maintenance tasks for consideration. 9 refs, 3 figs, 1 tab

Maintenance of auditory-nonverbal information in working memory.

Science.gov (United States)

Soemer, Alexander; Saito, Satoru

2015-12-01

According to the multicomponent view of working memory, both auditory-nonverbal information and auditory-verbal information are stored in a phonological code and are maintained by an articulation-based rehearsal mechanism (Baddeley, 2012). Two experiments have been carried out to investigate this hypothesis using sound materials that are difficult to label verbally and difficult to articulate. Participants were required to maintain 2 to 4 sounds differing in timbre over a delay of up to 12 seconds while performing different secondary tasks. While there was no convincing evidence for articulatory rehearsal as a main maintenance mechanism for auditory-nonverbal information, the results suggest that processes similar or identical to auditory imagery might contribute to maintenance. We discuss the implications of these results for multicomponent models of working memory.

Evidence that communication impairment in schizophrenia is associated with generalized poor task performance.

Science.gov (United States)

Merrill, Anne M; Karcher, Nicole R; Cicero, David C; Becker, Theresa M; Docherty, Anna R; Kerns, John G

2017-03-01

People with schizophrenia exhibit wide-ranging cognitive deficits, including slower processing speed and decreased cognitive control. Disorganized speech symptoms, such as communication impairment, have been associated with poor cognitive control task performance (e.g., goal maintenance and working memory). Whether communication impairment is associated with poorer performance on a broader range of non-cognitive control measures is unclear. In the current study, people with schizophrenia (n =51) and non-psychiatric controls (n =26) completed speech interviews allowing for reliable quantitative assessment of communication impairment. Participants also completed multiple goal maintenance and working memory tasks. In addition, we also examined (a) simple measures of processing speed involving highly automatic prepotent responses and (b) a non-cognitive control measure of general task performance. Schizophrenia communication impairment was significantly associated with poor performance in all cognitive domains, with the largest association found with processing speed (r s =-0.52). Further, communication impairment was also associated with the non-cognitive control measure of poor general task performance (r s =-0.43). In contrast, alogia, a negative speech symptom, and positive symptoms were less if at all related to cognitive task performance. Overall, this study suggests that communication impairment in schizophrenia may be associated with relatively generalized poor cognitive task performance. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Application of estimating effective dose from external radiation using two dosimeters during maintenance periods at KNPPS

International Nuclear Information System (INIS)

Kim, Hee Geun; Kong, Tae Young

2008-01-01

The application of a two-dosimeter and its algorithm and a test of its use in an inhomogeneous high radiation field are described. The goal was to develop an improved method for estimating the effective dose during maintenance periods at Korean nuclear power plants (NPPs). The use of the method in domestic and international NPPs including USA, Canada and Japan was also investigated. The algorithms used by the Canadian Ontario Power Generation (OPG) and American ANSI HPS N13.41, Lakshmanan, NCRP, EPRI and Texas A and M University were extensively analyzed as two-dosimeter algorithms. The possibility of their application to NPPs was evaluated using data for each algorithm from two-dosimeter results for an inhomogeneous high radiation field during maintenance periods at Korean NPPs. (author)

Demonstration of reliability centered maintenance

International Nuclear Information System (INIS)

Schwan, C.A.; Morgan, T.A.

1991-04-01

Reliability centered maintenance (RCM) is an approach to preventive maintenance planning and evaluation that has been used successfully by other industries, most notably the airlines and military. Now EPRI is demonstrating RCM in the commercial nuclear power industry. Just completed are large-scale, two-year demonstrations at Rochester Gas ampersand Electric (Ginna Nuclear Power Station) and Southern California Edison (San Onofre Nuclear Generating Station). Both demonstrations were begun in the spring of 1988. At each plant, RCM was performed on 12 to 21 major systems. Both demonstrations determined that RCM is an appropriate means to optimize a PM program and improve nuclear plant preventive maintenance on a large scale. Such favorable results had been suggested by three earlier EPRI pilot studies at Florida Power ampersand Light, Duke Power, and Southern California Edison. EPRI selected the Ginna and San Onofre sites because, together, they represent a broad range of utility and plant size, plant organization, plant age, and histories of availability and reliability. Significant steps in each demonstration included: selecting and prioritizing plant systems for RCM evaluation; performing the RCM evaluation steps on selected systems; evaluating the RCM recommendations by a multi-disciplinary task force; implementing the RCM recommendations; establishing a system to track and verify the RCM benefits; and establishing procedures to update the RCM bases and recommendations with time (a living program). 7 refs., 1 tab

Skin Conductance Level Reactivity Moderates the Association Between Harsh Parenting and Growth in Child Externalizing Behavior

OpenAIRE

Erath, Stephen A.; El-Sheikh, Mona; Hinnant, J. Benjamin; Cummings, E. Mark

2011-01-01

Skin conductance level reactivity (SCLR) was examined as a moderator of the association between harsh parenting at age 8 years and growth in child externalizing behavior from age 8 to age 10 (N = 251). Mothers and fathers provided reports of harsh parenting and their children’s externalizing behavior; children also provided reports of harsh parenting. SCLR was assessed in response to a socioemotional stress task and a problem-solving challenge task. Latent growth modeling revealed that boys w...

RA Reactor operation and maintenance (I-IX), Part I; Pogon i odrzavanje reaktora RA (I-IX), I Deo

Energy Technology Data Exchange (ETDEWEB)

Zecevic, V [Institute of Nuclear Sciences Boris Kidric, Reaktor RA, Vinca, Beograd (Serbia and Montenegro)

1963-12-15

The report on RA reactor operation and maintenance for year 1963 is divided in six tasks. This volume contains the introductory report, and three tasks of the final report, namely reactor exploitation, reactivity changes of the RA reactor before repair, planning of refuelling.

Mobile devices applied in the maintenance; Dispositivos moveis aplicados na manutencao

Energy Technology Data Exchange (ETDEWEB)

Ribeiro, Robison Tirre; Monteiro, Claudio Rogerio; Oliveira, Hudson Texeira de; Pacheco, Rogerio da Silva; Milrad, Shlomo [Transportadora Brasileira Gasoduto Bolivia Brasil S.A., Rio de Janeiro, RJ (Brazil)

2004-07-01

In natural gas pipeline companies, like TBG (Transportadora Brasileira Gasoduto Bolivia Brasil S.A.), with large extensions of pipes and installations distributed so far from each other it is usual that maintenance personnel go to the field job and sometimes do not come back to the office at the same day. In addition, the need to access the corporate network to input maintenance data in the Maintenance Module of Enterprise Resource Planning means that maintenance registries are something that do not flow easily from field to database. Technicians also spend a lot of time in front of the computer decreasing their productive working hours. Being aware of the importance of data to a consistent integrity pipeline program and to solve the problems related above, TBG implemented Maintenance in the Palm of the Hand project and distributed hand held PCs to all technicians, with software that works like an electronic maintenance work order. This system permits to collect maintenance data in real time and also providing important information to help technicians perform their jobs. If necessary, they can start a maintenance request. At any moment it is possible to connect to the corporate network and download data to CMMS. This project allowed TBG to increase quality and reliability of maintenance data and speed of information flow from field to CMMS, eliminating the need to print work orders and data sheets, increasing the productivity of technicians and reducing the time spent on boring tasks such as taking notes. (author)

In-vessel maintenance remote manipulator system

International Nuclear Information System (INIS)

Jimenez, E.

1978-01-01

The radiation environment within the Tokamak Fusion Test Reactor (TFTR) vacuum vessel necessitates the development of a Remote Manipulator System (RMS) to perform required periodic inspection and maintenance tasks. The RMS must be able to perform dexterous operations and handle loads that exceed human capabilities. The limited size of the access ports on the TFTR vacuum vessel and the performance profile, defined by the various handling requirements, present unique design constraints. The design approach and formulation of a RMS configuration which satisfies TFTR requirements is presented herein

Ethnicity- and sex-based discrimination and the maintenance of self-esteem.

Science.gov (United States)

Lönnqvist, Jan-Erik; Hennig-Schmidt, Heike; Walkowitz, Gari

2015-01-01

The psychological underpinnings of labor market discrimination were investigated by having participants from Israel, the West Bank and Germany (N = 205) act as employers in a stylized employment task in which they ranked, set wages, and imposed a minimum effort level on applicants. State self-esteem was measured before and after the employment task, in which applicant ethnicity and sex were salient. The applicants were real people and all behavior was monetarily incentivized. Supporting the full self-esteem hypothesis of the social identity approach, low self-esteem in women was associated with assigning higher wages to women than to men, and such behavior was related to the maintenance of self-esteem. The narrower hypothesis that successful intergroup discrimination serves to protect self-esteem received broader support. Across all participants, both ethnicity- and sex-based discrimination of out-groups were associated with the maintenance of self-esteem, with the former showing a stronger association than the latter.

Ethnicity- and Sex-Based Discrimination and the Maintenance of Self-Esteem

Science.gov (United States)

2015-01-01

The psychological underpinnings of labor market discrimination were investigated by having participants from Israel, the West Bank and Germany (N = 205) act as employers in a stylized employment task in which they ranked, set wages, and imposed a minimum effort level on applicants. State self-esteem was measured before and after the employment task, in which applicant ethnicity and sex were salient. The applicants were real people and all behavior was monetarily incentivized. Supporting the full self-esteem hypothesis of the social identity approach, low self-esteem in women was associated with assigning higher wages to women than to men, and such behavior was related to the maintenance of self-esteem. The narrower hypothesis that successful intergroup discrimination serves to protect self-esteem received broader support. Across all participants, both ethnicity- and sex-based discrimination of out-groups were associated with the maintenance of self-esteem, with the former showing a stronger association than the latter. PMID:25978646

Java Tool Framework for Automation of Hardware Commissioning and Maintenance Procedures

International Nuclear Information System (INIS)

Ho, J C; Fisher, J M; Gordon, J B; Lagin, L J; West, S L

2007-01-01

The National Ignition Facility (NIF) is a 192-beam laser system designed to study high energy density physics. Each beam line contains a variety of line replaceable units (LRUs) that contain optics, stepping motors, sensors and other devices to control and diagnose the laser. During commissioning and subsequent maintenance of the laser, LRUs undergo a qualification process using the Integrated Computer Control System (ICCS) to verify and calibrate the equipment. The commissioning processes are both repetitive and tedious when we use remote manual computer controls, making them ideal candidates for software automation. Maintenance and Commissioning Tool (MCT) software was developed to improve the efficiency of the qualification process. The tools are implemented in Java, leveraging ICCS services and CORBA to communicate with the control devices. The framework provides easy-to-use mechanisms for handling configuration data, task execution, task progress reporting, and generation of commissioning test reports. The tool framework design and application examples will be discussed

Transfer of Skills Evaluation for Assembly and Maintenance Training

Directory of Open Access Journals (Sweden)

Peveri Matteo

2011-12-01

Full Text Available One of the research topics within the EU-project SKILLS1 was the training of Industrial Maintenance and Assembly (IMA tasks. The IMA demonstrator developed comprehends two different training platforms, one based on technologies of Virtual Reality (VR and the other one on Augmented Reality (AR. To qualify the efficiency of the developed training systems different studies have been conducted, followed by a final “Transfer of Skill” evaluation that has been performed by service technicians at the “SIDEL industrial training centre” in Parma. This evaluation included qualitative methods (feedback collection in questionnaires as well as quantitative methods (experiments with control groups. The results demonstrate that both platforms are useful and suitable training tools for IMA tasks, and that the AR training decreased the number of unsolved errors in the task.

Development of the CAI system for inheritance of maintenance expertise

International Nuclear Information System (INIS)

Hanafusa, Hidemitsu; Chigusa, Naoki; Furuta, Kazuo

2002-01-01

High quality maintenance is required in order to secure the safety of nuclear power plants. The engineers engaged in maintenance activities have to master various knowledge, including the explicit and tacit knowledge of experienced experts, through education and training. Moreover, it is also very important to prevent these knowledge from getting scattered and lost with a change of generation and to share the knowledge or expertise. The purpose of this study is to develop a support system for the next generation experts to help them master and make use of the knowledge of their predecessors. The knowledge or expertise consist of ''knowledge about the maintenance tasks'', ''knowledge about structure/function of plant system/equipment'', and ''individual knowledge based on trouble experience etc.''. The ways this knowledge could be represented were considered first, then this support system was developed based on such representation. (author)

The right maintenance on the right components, at the right time, with the right parts: maintaining high plant reliability through an effective maintenance program

International Nuclear Information System (INIS)

Von Hatten, P.

2008-01-01

The objective of the maintenance program at a Nuclear Power Plant is to be proactive and prevent unexpected failures of equipment that can impact on Nuclear or Conventional Safety and Plant Production. This does not mean that all equipment failures will be prevented; in a number of cases the most cost effective solution is to allow equipment to run to failure. Deciding what components are critical to the plant is the first step. The industry uses guidance from INPO Advanced Process, AP913, to classify components as Critical, Non Critical or Run to Failure based on the consequence of the failure. Once this is complete, then the right maintenance program needs to be specified. This is done through utilization of experience from the industry based on the type of component. Maintenance strategies and templates have been produced for most power plant components. Each station or fleet needs then to apply the criteria, with exceptions as required, to determine the maintenance requirements and frequency for their components. This includes predictive and preventative maintenance. The more critical the component is the more rigorous the maintenance requirements. Once the maintenance program is defined it can be implemented. This requires that the Preventative Maintenance (PM's) are updated to ensure the correct tasks are in place and the frequency is correct. Work Management will group the PM's so they can scheduled efficiently and to minimize equipment down time. The last element is to ensure that the required parts are specified and are stocked or readily available for the maintenance when it is scheduled. This is an ongoing effort since components become obsolete or suppliers go out of business or change hands. (author)

JRR-3 maintenance program utilizing accumulated maintenance data

International Nuclear Information System (INIS)

Izumo, Hironobu; Kato, Tomoaki; Kinase, Masami; Torii, Yoshiya; Murayama, Yoji

2007-07-01

JRR-3(Japan Research Reactor No.3) has been operated for more than 15 years after the modification, without significant troubles by carrying out maintenance such as the preventive maintenance (mainly time-based maintenance) for the safety-grade equipments and the breakdown maintenance for the non-safety-grade equipments. Unscheduled shutdowns causes by aged non-safety-grade equipments have been increasing, and the resources such as budgets have been decreasing year by year. In this situation, JRR-3 maintenance program was reviewed about safety, reliability and economic efficiency. This report offers the policy of the maintenance review and the future direction of maintenance programs. (author)

Principles of MONJU maintenance. Characteristic of MONJU maintenance and reflection of LWR maintenance experience to FBR

International Nuclear Information System (INIS)

Nakai, Satoru; Nishio, Ryuichi; Uchihashi, Masaya; Kaneko, Yoshihisa; Yamashita, Hironobu; Yamaguchi, Atsunori; Aoki, Takayuki

2014-01-01

A sodium cooled fast breeder reactor (FBR) has unique systems and components and different degradation mechanism from light water reactor (LWR) so that need to establish maintenance technology in accordance with its features. The examination of the FBR maintenance technology is carried out in the special committee for considering the maintenance for Monju established in the Japan Society of Maintenology (JSM). As a result of the study such as extraction of Monju maintenance feature, maintenance technology benchmark between Monju and LWR components and survey of LWR maintenance experience, it is clear that principles of maintenance are same as LWR, necessity of LWR maintenance experience reflection and points to be considered in Monju maintenance. The road map to establish a FBR maintenance technology in the technical aspect became clear and it is vital to acquire operation and maintenance experience of the plant to implement this road map, and to establish a fast reactor maintenance. (author)

Opportunistic maintenance considering non-homogenous opportunity arrivals and stochastic opportunity durations

International Nuclear Information System (INIS)

Truong Ba, H.; Cholette, M.E.; Borghesani, P.; Zhou, Y.; Ma, L.

2017-01-01

Many systems and manufacturing processes undergo intermittent operation due to external factors (e.g. weather, low market prices), offering opportunities to conduct maintenance with reduced production losses. Making use of appropriate opportunities can thus lead to significant reduction in the total cost of maintenance and improvement in productivity. In this paper, an opportunistic maintenance (OM) model is developed considering two critical properties of real world opportunities: (i) non-homogeneous opportunity arrivals and (ii) stochastic opportunity duration. The model enables exploiting downtime cost savings from “partial” opportunities (stops shorter than the required maintenance time) thus extending the potential benefit of OM. The criteria for accepting maintenance opportunities are found by minimizing the single-cycle total cost. A closed form expression of the single-cycle total cost is derived for a given PM/OM policy and then a Genetic Algorithm is used to solve the optimization problem. Numerical results are presented to assess the benefit of opportunistic maintenance and the marginal benefit of considering partial opportunities. Results indicate that significant savings can be achieved by considering OM. Moreover, it is shown that the novel consideration of partial opportunities significantly increase the benefit of OM. - Highlights: • Opportunistic and time-based preventive maintenance jointly optimized. • Non-homogeneous opportunity arrivals and stochastic durations considered. • “Partial” opportunities considered for the first time. • Opportunity duration thresholds used as a decision criterion. • Numerical study conducted to evaluate benefit of optimized policy.

e-Learning Application for Machine Maintenance Process using Iterative Method in XYZ Company

Science.gov (United States)

Nurunisa, Suaidah; Kurniawati, Amelia; Pramuditya Soesanto, Rayinda; Yunan Kurnia Septo Hediyanto, Umar

2016-02-01

XYZ Company is a company based on manufacturing part for airplane, one of the machine that is categorized as key facility in the company is Millac 5H6P. As a key facility, the machines should be assured to work well and in peak condition, therefore, maintenance process is needed periodically. From the data gathering, it is known that there are lack of competency from the maintenance staff to maintain different type of machine which is not assigned by the supervisor, this indicate that knowledge which possessed by maintenance staff are uneven. The purpose of this research is to create knowledge-based e-learning application as a realization from externalization process in knowledge transfer process to maintain the machine. The application feature are adjusted for maintenance purpose using e-learning framework for maintenance process, the content of the application support multimedia for learning purpose. QFD is used in this research to understand the needs from user. The application is built using moodle with iterative method for software development cycle and UML Diagram. The result from this research is e-learning application as sharing knowledge media for maintenance staff in the company. From the test, it is known that the application make maintenance staff easy to understand the competencies.

Laboratory simulation of maintenance activity

International Nuclear Information System (INIS)

Kantowitz, B.H.

1988-01-01

Laboratory research in highly controlled settings can augment, but not replace, studies in plant or training center locations. A laboratory simulation involves abstraction of the human information processing and social interactions required in prototypical maintenance tasks. A variety of independent variables can be studied quickly, efficiently, and at relatively low cost. Sources of human error can be identified in terms of models of human perception, cognition, action, attention, and social/organizational processes. This paper discusses research in progress at the Battelle Human Performance Laboratory. Both theoretical aspects and practical implications are considered. Directions for future human factors research are indicated

Use of Job Task Analysis (JTA) in the development of craft training programs

International Nuclear Information System (INIS)

Gonyeau, J.A.; Long, R.E.

1985-01-01

Northern States Power Company is making a major effort to develop performance based training. It is finding the use of JTA data very helpful in the revision of its maintenance craft training programs. The technique being used involves a group of interns from the Training and Development Program of the University of Minnesota. These interns are largely graduate students, but with no nuclear and little mechanical/electrical experience. A Job Analysis for each discipline was used to: guide the following task analysis, determine program content, evaluate existing OJT check lists, and to define the four crafts used for mechanical maintenance. From the Job Analysis, a Training Task List was developed and correlated to training materials. The analysis of the tasks on the Training Task List is proceeding. Taxonomies of systems or subjects are compared to existing lesson plans. These taxonomies are useful when writing new lesson plans. The taxonomies are an excellent start for the development of enabling objectives. A Nine-Step Plan is being followed in the application of JTA data to the development and refinement of performance based training

Conditions of job performance quality during nuclear reactor maintenance

International Nuclear Information System (INIS)

Babos, K.; Takacs, J.

1991-01-01

The education and training programs of the maintenance personnel at the Paks Nuclear Power Plant, Hungary are described. In addition to well trained personnel, the conditions of job quality involves the preparation of job by proper check lists and availability of documentation, and the inspection and checking of the accomplishment of job tasks. Such an inspection procedure is proposed. (R.P.) 2 figs

Centralized operations and maintenance planning at the Atacama Large Millimeter/submillimeter Array (ALMA)

Science.gov (United States)

Lopez, Bernhard; Whyborn, Nicholas D.; Guniat, Serge; Hernandez, Octavio; Gairing, Stefan

2016-07-01

The Atacama Large Millimeter/submillimeter Array (ALMA) is a joint project between astronomical organizations in Europe, North America, and East Asia, in collaboration with the Republic of Chile. ALMA consists of 54 twelve-meter antennas and 12 seven-meter antennas operating as an aperture synthesis array in the (sub)millimeter wavelength range. Since the inauguration of the observatory back in March 2013 there has been a continuous effort to establish solid operations processes for effective and efficient management of technical and administrative tasks on site. Here a key aspect had been the centralized maintenance and operations planning: input is collected from science stakeholders, the computerized maintenance management system (CMMS) and from the technical teams spread around the world, then this information is analyzed and consolidated based on the established maintenance strategy, the observatory long-term plan and the short-term priorities definitions. This paper presents the high-level process that has been developed for the planning and scheduling of planned- and unplanned maintenance tasks, and for site operations like the telescope array reconfiguration campaigns. We focus on the centralized planning approach by presenting its genesis, its current implementation for the observatory operations including related planning products, and we explore the necessary next steps in order to fully achieve a comprehensive centralized planning approach for ALMA in steady-state operations.

The Ilizarov external fixator: what remains of the wire pretension after dynamic loading?

NARCIS (Netherlands)

Renard, A.J.S.; Schutte, B.G.; Verdonschot, N.J.J.; Kampen, A. van

2005-01-01

BACKGROUND: Maintenance of wire pretension in an Ilizarov external fixator is dependent on the torque applied to the fixation bolts. We therefore measured immediately after surgery the clinically applied torques. The median value was only 10 N m (range 8-14N m). We wondered whether this value is

The U.S. Federal Highway Administration winter Maintenance Decision Support System (MDSS) project

Energy Technology Data Exchange (ETDEWEB)

Pisano, P.A. [Federal Highway Administration, Road Weather Managment Program, Washington, D.C. (United States); Stern, A.D. [Mitretek Systems, Inc., Oceanic, Atmospheric and Space Systems, Falls Church, VA (United States); Mahoney, W.P. [National Center for Atmospheric Research, Research Applications Program, Boulder, CO (United States)

2004-07-01

Managing a winter maintenance program today is an increasingly complex endeavor. Just making sure that a plow blade is at the ready when the first flake falls is only a small part of the task. With tight budgets and the high expectation of the public for keeping roads clear of snow and ice, today's maintenance manager has to be able to handle multiple tasks or risk getting behind the onslaught of winter weather. Good information leads to effective practices, however all of the regulations concerning chemical applications, environmental impacts and multiple, often contradictory weather forecasts can lead to information overload. The United States Department of Transportation (DOT), Federal Highway Administration (FHWA) recognized this potential problem in the late 1990's as part of its Road Weather Management (RWM) program. Generally speaking, there were plenty of weather forecasts, along with a few companies that issued road-specific forecasts, but there was a lack of linkage between the information available and the decisions made by winter maintenance managers. It was this weak link that became the genesis for the winter Maintenance Decision Support System (MDSS). The MDSS has since matured into a functional prototype. During the winter of 2002-2003, the prototype was deployed at several maintenance garages in central Iowa for a field demonstration. This paper will document the implementation of the demonstration, a summary of lessons learned, and technology transfer activities. It will also describe plans for a longer, more comprehensive demonstration during the winter of 2003-2004. (orig.)

Preliminary Analysis of ISS Maintenance History and Implications for Supportability of Future Missions

Science.gov (United States)

Watson, Kevin J.; Robbins, William W.

2004-01-01

The International Space Station (ISS) enables the study of supportability issues associated with long-duration human spaceflight. The ISS is a large, complex spacecraft that must be maintained by its crew. In contrast to the Space Shuttle Orbiter vehicle, but similar to spacecraft that will be component elements of future missions beyond low-Earth orbit, ISS does not return to the ground for servicing and provisioning of spares is severely constrained by transportation limits. Although significant technical support is provided by ground personnel, all hands-on maintenance tasks are performed by the crew. It is expected that future missions to distant destinations will be further limited by lack of resupply opportunities and will, eventually, become largely independent of ground support. ISS provides an opportunity to begin learning lessons that will enable future missions to be successful. Data accumulated over the first several years of ISS operations have been analyzed to gain a better understanding of maintenance-related workload. This analysis addresses both preventive and corrective maintenance and includes all U.S segment core systems. Systems and tasks that are major contributors to workload are identified. As further experience accrues, lessons will be learned that will influence future system designs so that they require less maintenance and, when maintenance is required, it can be performed more efficiently. By heeding the lessons of ISS it will be possible to identify system designs that should be more robust and point towards advances in both technology and design that will offer the greatest return on investment.

Dissociating rehearsal and refreshing in the maintenance of verbal information in 8-year-old children

Science.gov (United States)

Mora, Gérome; Camos, Valérie

2015-01-01

Recent models of working memory suggest that two systems are involved in verbal working memory: one is dedicated to the maintenance of phonological representations through verbal rehearsal, while the other would maintain multimodal representations through attentional refreshing (Camos et al., 2009; Baddeley, 2012). Previous studies provided evidence on the existence of these two maintenance systems, on their independence, and how they affect recall performance in adults. However, only one study had already explored the relationships between these two systems in children ( Tam et al., 2010). The aim of the present study was to further examine how the two systems account for working memory performance in children. Eight-year-old children performed complex span tasks in which the availability of either the rehearsal or the refreshing was impeded by a concurrent articulation or an attention-demanding task, respectively. Moreover, the phonological similarity of the memoranda was manipulated. Congruently with studies showing that older children can used these maintenance systems, impeding any of the two systems reduced recall performance. Moreover, the manipulation of the two mechanisms did not interact, as previously observed in adults. This suggests that the two maintenance mechanisms are independent in 8-year-old children as they are in adults. However, the results concerning the phonological similarity effect (PSE) differed from what is observed in adults. Whereas the PSE relies only on the availability of rehearsal in adults, a more complex pattern appeared in children: the concurrent articulation as well as the concurrent task modulated the emergence of the PSE. PMID:25667577

Dissociating Rehearsal and Refreshing in the Maintenance of Verbal Information in 8-Year-Old Children

Directory of Open Access Journals (Sweden)

Gérome eMora

2015-01-01

Full Text Available Recent models of working memory suggest that two systems are involved in verbal working memory: one is dedicated to the maintenance of phonological representations through verbal rehearsal, while the other would maintain multimodal representations through attentional refreshing (Baddeley, 2012; Camos et al., 2009. Previous studies provided evidence on the existence of these two maintenance systems, on their independence, and how they affect recall performance in adults. However, only one study had already explored the relationships between these two systems in children (Tam et al., 2010. The aim of the present study was to further examine how the two systems account for working memory performance in children. Eight-year-old children performed complex span tasks in which the availability of either the rehearsal or the refreshing was impeded by a concurrent articulation or an attention-demanding task, respectively. Moreover, the phonological similarity of the memoranda was manipulated. Congruently with studies showing that older children can used these maintenance systems, impeding any of the two systems reduced recall performance. Moreover, the manipulation of the two mechanisms did not interact, as previously observed in adults. This suggests that the two maintenance mechanisms are independent in 8-year-old children as they are in adults. However, the results concerning the phonological similarity effect differed from what is observed in adults. Whereas the phonological similarity effect relies only on the availability of rehearsal in adults, a more complex pattern appeared in children: the concurrent articulation as well as the concurrent task modulated the emergence of the phonological similarity effect.

Dissociating rehearsal and refreshing in the maintenance of verbal information in 8-year-old children.

Science.gov (United States)

Mora, Gérome; Camos, Valérie

2015-01-01

Recent models of working memory suggest that two systems are involved in verbal working memory: one is dedicated to the maintenance of phonological representations through verbal rehearsal, while the other would maintain multimodal representations through attentional refreshing (Camos et al., 2009; Baddeley, 2012). Previous studies provided evidence on the existence of these two maintenance systems, on their independence, and how they affect recall performance in adults. However, only one study had already explored the relationships between these two systems in children ( Tam et al., 2010). The aim of the present study was to further examine how the two systems account for working memory performance in children. Eight-year-old children performed complex span tasks in which the availability of either the rehearsal or the refreshing was impeded by a concurrent articulation or an attention-demanding task, respectively. Moreover, the phonological similarity of the memoranda was manipulated. Congruently with studies showing that older children can used these maintenance systems, impeding any of the two systems reduced recall performance. Moreover, the manipulation of the two mechanisms did not interact, as previously observed in adults. This suggests that the two maintenance mechanisms are independent in 8-year-old children as they are in adults. However, the results concerning the phonological similarity effect (PSE) differed from what is observed in adults. Whereas the PSE relies only on the availability of rehearsal in adults, a more complex pattern appeared in children: the concurrent articulation as well as the concurrent task modulated the emergence of the PSE.

Olfactory short-term memory encoding and maintenance - an event-related potential study.

Science.gov (United States)

Lenk, Steffen; Bluschke, Annet; Beste, Christian; Iannilli, Emilia; Rößner, Veit; Hummel, Thomas; Bender, Stephan

2014-09-01

This study examined whether the memory encoding and short term maintenance of olfactory stimuli is associated with neurophysiological activation patterns which parallel those described for sensory modalities such as vision and auditory. We examined olfactory event-related potentials in an olfactory change detection task in twenty-four healthy adults and compared the measured activation to that found during passive olfactory stimulation. During the early olfactory post-processing phase, we found a sustained negativity over bilateral frontotemporal areas in the passive perception condition which was enhanced in the active memory task. There was no significant lateralization in either experimental condition. During the maintenance interval at the end of the delay period, we still found sustained activation over bilateral frontotemporal areas which was more negative in trials with correct - as compared to incorrect - behavioural responses. This was complemented by a general significantly stronger frontocentral activation. Summarizing, we were able to show that olfactory short term memory involves a parallel sequence of activation as found in other sensory modalities. In addition to olfactory-specific frontotemporal activations in the memory encoding phase, we found slow cortical potentials over frontocentral areas during the memory maintenance phase indicating the activation of a supramodal memory maintenance system. These findings could represent the neurophysiological underpinning of the 'olfactory flacon', the olfactory counter-part to the visual sketchpad and phonological loop embedded in Baddeley's working memory model. Copyright © 2014 Elsevier Inc. All rights reserved.

Ontology Maintenance using Textual Analysis

Directory of Open Access Journals (Sweden)

Yassine Gargouri

2003-10-01

Full Text Available Ontologies are continuously confronted to evolution problem. Due to the complexity of the changes to be made, a maintenance process, at least a semi-automatic one, is more and more necessary to facilitate this task and to ensure its reliability. In this paper, we propose a maintenance ontology model for a domain, whose originality is to be language independent and based on a sequence of text processing in order to extract highly related terms from corpus. Initially, we deploy the document classification technique using GRAMEXCO to generate classes of texts segments having a similar information type and identify their shared lexicon, agreed as highly related to a unique topic. This technique allows a first general and robust exploration of the corpus. Further, we apply the Latent Semantic Indexing method to extract from this shared lexicon, the most associated terms that has to be seriously considered by an expert to eventually confirm their relevance and thus updating the current ontology. Finally, we show how the complementarity between these two techniques, based on cognitive foundation, constitutes a powerful refinement process.

Task Interruption: Resumption Lag and the Role of Cues

National Research Council Canada - National Science Library

Altmann, Erik M; Trafton, J. G

2004-01-01

...), indicating a substantial disruptive effect. To probe the nature of the disruption, they examined the role of external cues associated with the interrupted task and found that cues available immediately before an interruption facilitate performance immediately afterwards, thus reducing the resumption lag. This "cue-availability" effect suggests that people deploy preparatory perceptual and memory processes, apparently spontaneously, to mitigate the disruptive effects of task interruption.

Sensor-driven, fault-tolerant control of a maintenance robot

International Nuclear Information System (INIS)

Moy, M.M.; Davidson, W.M.

1987-01-01

A robot system has been designed to do routine maintenance tasks on the Sandia Pulsed Reactor (SPR). The use of this Remote Maintenance Robot (RMR) is expected to significantly reduce the occupational radiation exposure of the reactor operators. Reactor safety was a key issue in the design of the robot maintenance system. Using sensors to detect error conditions and intelligent control to recover from the errors, the RMR is capable of responding to error conditions without creating a hazard. This paper describes the design and implementation of a sensor-driven, fault-tolerant control for the RMR. Recovery from errors is not automatic; it does rely on operator assistance. However, a key feature of the error recovery procedure is that the operator is allowed to reenter the programmed operation after the error has been corrected. The recovery procedure guarantees that the moving components of the system will not collide with the reactor during recovery

Verbal monitoring in Parkinson’s disease: A comparison between internal and external monitoring

Science.gov (United States)

Mertens, Jolien; Mariën, Peter; Santens, Patrick; Pickut, Barbara A.; Hartsuiker, Robert J.

2017-01-01

Patients with Parkinson’s disease (PD) display a variety of impairments in motor and non-motor language processes; speech is decreased on motor aspects such as amplitude, prosody and speed and on linguistic aspects including grammar and fluency. Here we investigated whether verbal monitoring is impaired and what the relative contributions of the internal and external monitoring route are on verbal monitoring in patients with PD relative to controls. Furthermore, the data were used to investigate whether internal monitoring performance could be predicted by internal speech perception tasks, as perception based monitoring theories assume. Performance of 18 patients with Parkinson’s disease was measured on two cognitive performance tasks and a battery of 11 linguistic tasks, including tasks that measured performance on internal and external monitoring. Results were compared with those of 16 age-matched healthy controls. PD patients and controls generally performed similarly on the linguistic and monitoring measures. However, we observed qualitative differences in the effects of noise masking on monitoring and disfluencies and in the extent to which the linguistic tasks predicted monitoring behavior. We suggest that the patients differ from healthy subjects in their recruitment of monitoring channels. PMID:28832595

Psychological factors associated with weight loss maintenance: theory-driven practice for nurse practitioners.

Science.gov (United States)

Valek, Rebecca M; Greenwald, Beverly J; Lewis, Carolyn C

2015-04-01

The authors discuss the psychological factors associated with weight loss maintenance and the use of Pender's health promotion model as a guide for the construction of clinical interventions to address these factors. The psychological factors include internal drive for weight maintenance, ongoing self-monitoring, long-term flexibility, positive mood and emotions, appropriate goals, and management of external stimuli. Nurse practitioners can help combat obesity trends through caring for patients in a holistic manner. Periodic psychological needs-assessments for patients who desire to maintain weight loss may further promote long-term success in weight management. © The Author(s) 2015.

RA Reactor operation and maintenance (I-IX), part VII, Task 3.08/04, Refurbishment of the RA reactor

International Nuclear Information System (INIS)

Zecevic, V.

1963-12-01

This volume covers the following reports concerned with the maintenance and repair work of the RA reactor: repair of the technical water system; maintenance of the transportation equipment; vacuuming and drying during refurbishment; repair and decontamination of the distillation device; and the report on participation of the operational dosimetry division in the RA reactor refurbishment activities

Swimming Pool Hygiene: Self-Monitoring, Task Clarification, and Performance Feedback Increase Lifeguard Cleaning Behaviors

Science.gov (United States)

Rose, Henry M. S.; Ludwig, Timothy D.

2009-01-01

The effects of task clarification, self-monitoring, and performance feedback on cleaning behaviors of 9 lifeguards in 3 performance areas (vacuuming, lobby tidying, and pool deck maintenance) were investigated using an ABA reversal design at a county swim complex. A specific task in each performance area was used as a behavioral control. Following…

Two-dimensional systolic-array architecture for pixel-level vision tasks

Science.gov (United States)

Vijverberg, Julien A.; de With, Peter H. N.

2010-05-01

This paper presents ongoing work on the design of a two-dimensional (2D) systolic array for image processing. This component is designed to operate on a multi-processor system-on-chip. In contrast with other 2D systolic-array architectures and many other hardware accelerators, we investigate the applicability of executing multiple tasks in a time-interleaved fashion on the Systolic Array (SA). This leads to a lower external memory bandwidth and better load balancing of the tasks on the different processing tiles. To enable the interleaving of tasks, we add a shadow-state register for fast task switching. To reduce the number of accesses to the external memory, we propose to share the communication assist between consecutive tasks. A preliminary, non-functional version of the SA has been synthesized for an XV4S25 FPGA device and yields a maximum clock frequency of 150 MHz requiring 1,447 slices and 5 memory blocks. Mapping tasks from video content-analysis applications from literature on the SA yields reductions in the execution time of 1-2 orders of magnitude compared to the software implementation. We conclude that the choice for an SA architecture is useful, but a scaled version of the SA featuring less logic with fewer processing and pipeline stages yielding a lower clock frequency, would be sufficient for a video analysis system-on-chip.

Relationship between Quality of Building Maintenance System and Occupant Satisfaction for Office Buildings

Directory of Open Access Journals (Sweden)

Hamid A.H.A

2014-03-01

Full Text Available Buildings will be weary, decaying and dirty as time goes by; but with highquality maintenance management we can prolong the life-span of building, provide building services and keep the building performance at its ultimate level. The importance of carrying out a systematic and routine maintenance is to conserve building performance. However, this task is often neglected due to various factors including misunderstanding the needs of the maintenance works and lack of budget allocation. This paper highlights the current practice of maintenance management that are being implemented in 6 office buildings located in Kuala Lumpur, Johor, Kedah and Pulau Pinang. Using the responses of questionnaire answered by 150 respondents employed from these selected offices, personal interviews and visual inspection the following findings were made: the occupants were satisfied with the maintenance management of their buildings elements and the delivery characteristics of maintenance works. Visual inspection however showed that some elements are not in a good condition. In conclusion, some recommendations are made to improve the existing system including the establishment of a maintenance plan, selection of experienced contractors and the provision of a service desk.

A Study on Relationships between Functional Performance and Task Performance Measure through Experiments in NPP MCR

International Nuclear Information System (INIS)

Jang, In Seok; Seong, Poong Hyun; Park, Jin Kyun

2011-01-01

Further improvements in levels of organization, management, man-machine interfaces, education, training, etc. are required, if high operating reliability of operators in huge and complex plants such as chemical plants and electrical power generating plants is to be maintained. Improvement requires good understanding of operators' behavior, including defining what is good performance for operators, especially in emergency situations. Human performance measures, therefore, are important to enhance performance and to reduce the probability of incidents and accidents in Nuclear Power Plants (NPPs). Operators' performance measures are used for multi-objectives such as control room design, human system interface evaluation, training, procedure and so on. There are two kinds of representative methods to measure operators' performance. These methods are now known as the functional performance measure and task performance measure. Functional performance measures are basically based on the plant process parameters. Functional performance measures indicate how well the operators controlled selected critical parameters. The parameters selected in this paper are derived from the four Critical Safety Functions (CSFs) identified in the emergency operating procedures such as achievement of subcriticality, maintenance of core cooling, maintenance of heat sink and maintenance of containment integrity. Task performance measures are based on the task analysis. Task analysis is to determine the tasks required and how operators are performed. In this paper, task analysis is done with ideal path for an accident completed by experts and Emergency Operation Procedure (EOP). However, most literatures related to operators' performance have been using one of these measures and there is no research to find out the relationships between two measures. In this paper, the relationships between functional performance measure and task performance measure are investigated using experiments. Shortly

Preventive Maintenance Scheduling for Multicogeneration Plants with Production Constraints Using Genetic Algorithms

Directory of Open Access Journals (Sweden)

Khaled Alhamad

2015-01-01

Full Text Available This paper describes a method developed to schedule the preventive maintenance tasks of the generation and desalination units in separate and linked cogeneration plants provided that all the necessary maintenance and production constraints are satisfied. The proposed methodology is used to generate two preventing maintenance schedules, one for electricity and the other for distiller. Two types of crossover operators were adopted, 2-point and 4-point. The objective function of the model is to maximize the available number of operational units in each plant. The results obtained were satisfying the problem parameters. However, 4-point slightly produce better solution than 2-point ones for both electricity and water distiller. The performance as well as the effectiveness of the genetic algorithm in solving preventive maintenance scheduling is applied and tested on a real system of 21 units for electricity and 21 units for water. The results presented here show a great potential for utility applications for effective energy management over a time horizon of 52 weeks. The model presented is an effective decision tool that optimizes the solution of the maintenance scheduling problem for cogeneration plants under maintenance and production constraints.

Simulation of machine-maintenance training in virtual environment

International Nuclear Information System (INIS)

Yoshikawa, Hidekazu; Tezuka, Tetsuo; Kashiwa, Ken-ichiro; Ishii, Hirotake

1997-01-01

The periodical inspection of nuclear power plants needs a lot of workforces with a high degree of technical skill for the maintenance of various sorts of machines. Therefore, a new type of maintenance training system is required, where trainees can get training safely, easily and effectively. In this study we developed a training simulation system for disassembling a check valve in virtual environment (VE). The features of this system are as follows: Firstly, the trainees can execute tasks even in wrong order, and can experience the resultant conditions. In order to realize this environment, we developed a new Petri-net model for representing the objects' states in VE. This Petri-net model has several original characteristics, which make it easier to manage the change of the objects' states. Furthermore, we made a support system for constructing the Petri-net model of machine-disassembling training, because the Petri-net model is apt to become of large size. The effectiveness of this support system is shown through the system development. Secondly, this system can perform appropriate tasks to be done next in VE whenever the trainee wants even after some mistakes have been made. The effectiveness of this function has also been confirmed by experiments. (author)

Job analysis of the maintenance supervisor and instrument and control supervisor positions for the nuclear power plant maintenance personnel reliability model

International Nuclear Information System (INIS)

Bartter, W.D.; Siegel, A.I.; Federman, P.J.

1982-11-01

The present report presents the results of an analysis of the jobs of maintenance mechanic supervisors and instrument and control technician supervisors in nuclear power plants. Such an analysis was considered to be a necessary step in defining the scope and focus of a model for predicting and analyzing nuclear power maintenance reliability. The model will focus upon tasks and subtasks performed by various job positions. The results of this job analysis, along with the results of a survey of user needs vis-a-vis such a model and the results of parallel analyses of the job of maintenance mechanics and of instrument and control technicians provide the sound foundation on which such a model may be built. Job analysis possesses implications for a number of purposes. It provides insight into selection standards, job structuring and organization, performance analysis, training objective establishment, and training content derivation. Accordingly, the results of the present work possess implications for a variety of interest areas relative to safe and efficient operation of nuclear power plants

External plans for radiological emergency

International Nuclear Information System (INIS)

Suarez, G.; Vizuet G, J.; Benitez S, J.A.

1999-01-01

Since 1989, the National Institute of Nuclear Research in Mexico shares in the task of Food and Water Control corresponding to the FT-86 task force of External Plans for Radiological Emergency (PERE), in charge of the Veracruz Health Services. In the PERE preparation stage previous actions are necessary developed for the preparation and updating of this plan and the task organization with the purpose to maintaining standing and operable in any time and circumstance, the capability to response in the face of an emergency. This stage englobes activities which must be realized before to carry out the Plan as they are the specialized training of personnel which participates and the execution of exercises and simulacrums. Until 1998, training and exercises for this task had been realized under diverse possible sceneries but in conditions that simulated the presence of radioactive material. For this reason, it should be emphasized the training realized during the days 6th, 7th, 8th July, 1999, in the emergency planning zone of the Plan, which to carry out using radioactive material. The National Institute of Nuclear Research had in charge of the training. This work describes all the activities for the realization of this training. (Author)

Neurological Correlates of Reward Responding in Adolescents With and Without Externalizing Behavior Disorders

Science.gov (United States)

Gatzke-Kopp, Lisa M.; Beauchaine, Theodore P.; Shannon, Katherine E.; Chipman, Jane; Fleming, Andrew P.; Crowell, Sheila E.; Liang, Olivia; Aylward, Elizabeth; Johnson, L. Clark

2009-01-01

Opposing theories of striatal hyper- and hypodopaminergic functioning have been suggested in the pathophysiology of externalizing behavior disorders. To test these competing theories, the authors used functional MRI to evaluate neural activity during a simple reward task in 12- to 16-year-old boys with attention-deficit/hyperactivity disorder and/or conduct disorder (n = 19) and in controls with no psychiatric condition (n = 11). The task proceeded in blocks during which participants received either (a) monetary incentives for correct responses or (b) no rewards for correct responses. Controls exhibited striatal activation only during reward, shifting to anterior cingulate activation during nonreward. In contrast, externalizing adolescents exhibited striatal activation during both reward and nonreward. Externalizing psychopathology appears to be characterized by deficits in processing the omission of predicted reward, which may render behaviors that are acquired through environmental contingencies difficult to extinguish when those contingencies change. PMID:19222326

Innovative techniques in maintenance training

International Nuclear Information System (INIS)

Soileau, J.B.; Blackwell, C.; Rackos, N.; Elmer, L.B.

1991-01-01

Performance based training has its beginning with a Job and Task Analysis (JTA), and culminates with the presentation of the developed training material. For optimum training effectiveness, a post training feedback mechanism is utilized to update and/or upgrade material content. A Job Task Analysis uses subject matter experts and supporting documentation to define the skills and knowledge necessary to perform functions from total position responsibilities to the simplest tasks, depending on desired results. Once skills and knowledge are defined, decisions on needed curriculum can be made including objectives, exams, and training settings (classroom, lab, or job site). This focused curriculum and the determination of best training settings are innovations of the performanced based training system. Past training experience has illustrated that a baseline level of classroom training acts as a catalyst for optimum hands-on training. The trainee exits the training phase able to do the job proficiently. This provides the training customer with quality training with minimum investment. Maintenance Training at Comanche Peak Steam Electric Station (CPSES) integrates the knowledge and skill needs by providing the individual with focused classroom presentations followed by sufficient laboratory time to practice actual task activities. Labs are configured to represent plant equipment and work environment to the maximum extent possible and duplicate in-plant work orders and procedures are used. This allows actions to be analyzed and corrective feedback given as necessary. As an added benefit, any mistakes made during training has minimal, if any, impact on plant performance

A Skill-based Robot Co-worker for Industrial Maintenance Tasks

DEFF Research Database (Denmark)

Koch, Paul Jacob; van Amstel, Marike Koch; Dębska, Patrycja

2017-01-01

This paper investigates the concept of a sensor based robot co-worker working in flexible industrial environments together with and alongside human operators. In this particular work, a realisation of a robot co-worker scenario is developed in order to demonstrate the implementation of a robot co......-worker from the starting point of an autonomous industrial mobile manipulator. The cobot is applied on the industrially relevant task of screwing by the use of a skill-based approach. The technical work on the human-robot interface and the screwing skill is described....

Managed maintenance, the next step in power plant maintenance

International Nuclear Information System (INIS)

Butterworth, G.; Anderson, T.M.

1984-01-01

The Westinghouse Nuclear Services Integration Division managed maintenance services are described. Essential to the management and control of a total plant maintenance programme is the development of a comprehensive maintenance specification. During recent years Westinghouse has jointly developed total plant engineering-based maintenance specifications with a number of utilities. The process employed and the experience to date are described. To efficiently implement the maintenance programme Westinghouse has developed a computer software program specifically designed for day to day use at the power plant by maintenance personnel. This program retains an equipment maintenance history, schedules maintenance activities, issues work orders and performs a number of sophisticated analyses of the maintenance backlog and forecast, equipment failure rates, etc. The functions of this software program are described and details of Westinghouse efforts to support the utilities in reducing outage times through development of predefined outage plans for critical report maintenance activities are given. Also described is the experience gained in the training of specialized maintenance personnel, employing competency-based training techniques and equipment mock-ups, and the benefits experienced, in terms of improved quality and productivity of maintenance performed. The success experienced with these methods has caused Westinghouse to expand the use of these training techniques to the more routine skill areas of power plant maintenance. A significant reduction in the operating costs of nuclear power plants will only be brought about by a significant improvement in the quality of maintenance. Westinghouse intends to effect this change by expanding its international service capabilities and to make major investments in order to promote technological developments in the area of power plant maintenance. (author)

Development and Implementation of a Condition Based Maintenance Program for Geothermal Power Plants; FINAL

International Nuclear Information System (INIS)

Steve Miller; Jim Eddy; Murray Grande; Shawn Bratt; Manuchehr Shirmohamadi

2002-01-01

This report describes the development of the RCM team, identifying plant assets and developing an asset hierarchy, the development of sample Failure Mode Effects Analysis (FMEAs), identifying and prioritizing plant systems and components for RCM analysis, and identifying RCM/CBM software/hardware vendors. It also includes the Failure Mode Effects Analysis (FMEA) for all Class I Systems, Maintenance Task Assignments, use of Conditioned Based Maintenance (CBM) Tools and Displays of the RCM software System Development to date

Application of reliability-centered maintenance to boiling water reactor emergency core cooling systems fault-tree analysis

International Nuclear Information System (INIS)

Choi, Y.A.; Feltus, M.A.

1995-01-01

Reliability-centered maintenance (RCM) methods are applied to boiling water reactor plant-specific emergency core cooling system probabilistic risk assessment (PRA) fault trees. The RCM is a technique that is system function-based, for improving a preventive maintenance (PM) program, which is applied on a component basis. Many PM programs are based on time-directed maintenance tasks, while RCM methods focus on component condition-directed maintenance tasks. Stroke time test data for motor-operated valves (MOVs) are used to address three aspects concerning RCM: (a) to determine if MOV stroke time testing was useful as a condition-directed PM task; (b) to determine and compare the plant-specific MOV failure data from a broad RCM philosophy time period compared with a PM period and, also, compared with generic industry MOV failure data; and (c) to determine the effects and impact of the plant-specific MOV failure data on core damage frequency (CDF) and system unavailabilities for these emergency systems. The MOV stroke time test data from four emergency core cooling systems [i.e., high-pressure coolant injection (HPCI), reactor core isolation cooling (RCIC), low-pressure core spray (LPCS), and residual heat removal/low-pressure coolant injection (RHR/LPCI)] were gathered from Philadelphia Electric Company's Peach Bottom Atomic Power Station Units 2 and 3 between 1980 and 1992. The analyses showed that MOV stroke time testing was not a predictor for eminent failure and should be considered as a go/no-go test. The failure data from the broad RCM philosophy showed an improvement compared with the PM-period failure rates in the emergency core cooling system MOVs. Also, the plant-specific MOV failure rates for both maintenance philosophies were shown to be lower than the generic industry estimates

Differential effects of cognitive load on emotion: Emotion maintenance versus passive experience.

Science.gov (United States)

DeFraine, William C

2016-06-01

Two separate lines of research have examined the effects of cognitive load on emotional processing with similar tasks but seemingly contradictory results. Some research has shown that the emotions elicited by passive viewing of emotional images are reduced by subsequent cognitive load. Other research has shown that such emotions are not reduced by cognitive load if the emotions are actively maintained. The present study sought to compare and resolve these 2 lines of research. Participants either passively viewed negative emotional images or maintained the emotions elicited by the images, and after a delay rated the intensity of the emotion they were feeling. Half of trials included a math task during the delay to induce cognitive load, and the other half did not. Results showed that cognitive load reduced the intensity of negative emotions during passive-viewing of emotional images but not during emotion maintenance. The present study replicates the findings of both lines of research, and shows that the key factor is whether or not emotions are actively maintained. Also, in the context of previous emotion maintenance research, the present results support the theoretical idea of a separable emotion maintenance process. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

An external focus of attention enhances balance learning in older adults.

Science.gov (United States)

Chiviacowsky, Suzete; Wulf, Gabriele; Wally, Raquel

2010-10-01

Studies with young adults have shown that an external focus of attention (i.e., on the movement effect) results in more effective motor learning and greater automaticity than an internal focus (i.e., on one's own body movements). The present study examined whether instructions inducing an external versus internal attentional focus would differentially affect the learning of a balance task in 32 older adults (24 females and 8 males, mean age: 69.4 years), divided equally, by number and gender, into two groups. The task required participants to stand on a balance platform (stabilometer) tilting to the left and right, and to try to keep the platform as close to horizontal as possible during each 30-s trial. The external focus group was instructed to concentrate on keeping markers on the platform horizontal, while the internal focus group was instructed to concentrate on keeping their feet horizontal. The dependent variable was time in balance (i.e., platform movements within ± 5°). Participants performed 10 practice trials on day 1, with focus reminders given before each trial. Learning was assessed by a retention test, consisting of five trials without instructions, performed 1 day later. The external focus group outperformed the internal focus group in retention [F(4, 120)=3.46, p=.01]. The results demonstrate that the learning benefits of an external attentional focus are generalizable to older learners. Copyright © 2010 Elsevier B.V. All rights reserved.

Maintenance of non-consciously presented information engages the prefrontal cortex

Directory of Open Access Journals (Sweden)

Fredrik eBergström

2014-11-01

Full Text Available Conscious processing is generally seen as required for flexible and willful actions, as well as for tasks that require durable information maintenance. Here we present research that questions the assumption that only consciously perceived information is durable (> 500 ms. Using the attentional blink phenomenon, we rendered otherwise relatively clearly perceived letters non-conscious. In a first experiment we systematically manipulated the delay between stimulus presentation and response, for the purpose of estimating the durability of non-conscious perceptual representations. For items reported not seen, we found that behavioral performance was better than chance across intervals up to 15 seconds. In a second experiment we used fMRI to investigate the neural correlates underlying the maintenance of non-conscious perceptual representations. Critically, the relatively long delay period demonstrated in experiment 1 enabled isolation of the signal change specifically related to the maintenance period, separate from stimulus presentation and response. We found sustained BOLD signal change in the right mid-lateral prefrontal cortex, orbitofrontal cortex, and crus II of the cerebellum during maintenance of non-consciously perceived information. These findings are consistent with the controversial claim that working-memory mechanisms are involved in the short-term maintenance of non-conscious perceptual representations.

Program integration of predictive maintenance with reliability centered maintenance

International Nuclear Information System (INIS)

Strong, D.K. Jr; Wray, D.M.

1990-01-01

This paper addresses improving the safety and reliability of power plants in a cost-effective manner by integrating the recently developed reliability centered maintenance techniques with the traditional predictive maintenance techniques of nuclear power plants. The topics of the paper include a description of reliability centered maintenance (RCM), enhancing RCM with predictive maintenance, predictive maintenance programs, condition monitoring techniques, performance test techniques, the mid-Atlantic Reliability Centered Maintenance Users Group, test guides and the benefits of shared guide development

TH-A-BRC-00: New Task Groups for External Beam QA: An Overview

International Nuclear Information System (INIS)

2016-01-01

AAPM TG-135U1 QA for Robotic Radiosurgery - Sonja Dieterich Since the publication of AAPM TG-135 in 2011, the technology of robotic radiosurgery has rapidly developed. AAPM TG-135U1 will provide recommendations on the clinical practice for using the IRIS collimator, fiducial-less real-time motion tracking, and Monte Carlo based treatment planning. In addition, it will summarize currently available literature about uncertainties. Learning Objectives: Understand the progression of technology since the first TG publication Learn which new QA procedures should be implemented for new technologies Be familiar with updates to clinical practice guidelines AAPM TG-178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance - Steven Goetsch Purpose: AAPM Task Group 178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance was formed in August, 2008. The Task Group has 12 medical physicists, two physicians and two consultants. Methods: A round robin dosimetry intercomparison of proposed ionization chambers, electrometer and dosimetry phantoms was conducted over a 15 month period in 2011 and 2012 (Med Phys 42, 11, Nov, 2015). The data obtained at 9 institutions (with ten different Elekta Gamma Knife units) was analyzed by the lead author using several protocols. Results: The most consistent results were obtained using the Elekta ABS 16cm diameter phantom, with the TG-51 protocol modified as recommended by Alfonso et al (Med Phys 35, 11, Nov 2008). A key white paper (Med Phys, in press) sponsored by Elekta Corporation, was used to obtain correction factors for the ionization chambers and phantoms used in this intercomparison. Consistent results were obtained for both Elekta Gamma Knife Model 4C and Gamma Knife Perfexion units as measured with each of two miniature ionization chambers. Conclusion: The full report gives clinical history and background of gamma stereotactic radiosurgery, clinical examples and history, quality assurance recommendations and outline

TH-A-BRC-00: New Task Groups for External Beam QA: An Overview

Energy Technology Data Exchange (ETDEWEB)

NONE

2016-06-15

AAPM TG-135U1 QA for Robotic Radiosurgery - Sonja Dieterich Since the publication of AAPM TG-135 in 2011, the technology of robotic radiosurgery has rapidly developed. AAPM TG-135U1 will provide recommendations on the clinical practice for using the IRIS collimator, fiducial-less real-time motion tracking, and Monte Carlo based treatment planning. In addition, it will summarize currently available literature about uncertainties. Learning Objectives: Understand the progression of technology since the first TG publication Learn which new QA procedures should be implemented for new technologies Be familiar with updates to clinical practice guidelines AAPM TG-178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance - Steven Goetsch Purpose: AAPM Task Group 178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance was formed in August, 2008. The Task Group has 12 medical physicists, two physicians and two consultants. Methods: A round robin dosimetry intercomparison of proposed ionization chambers, electrometer and dosimetry phantoms was conducted over a 15 month period in 2011 and 2012 (Med Phys 42, 11, Nov, 2015). The data obtained at 9 institutions (with ten different Elekta Gamma Knife units) was analyzed by the lead author using several protocols. Results: The most consistent results were obtained using the Elekta ABS 16cm diameter phantom, with the TG-51 protocol modified as recommended by Alfonso et al (Med Phys 35, 11, Nov 2008). A key white paper (Med Phys, in press) sponsored by Elekta Corporation, was used to obtain correction factors for the ionization chambers and phantoms used in this intercomparison. Consistent results were obtained for both Elekta Gamma Knife Model 4C and Gamma Knife Perfexion units as measured with each of two miniature ionization chambers. Conclusion: The full report gives clinical history and background of gamma stereotactic radiosurgery, clinical examples and history, quality assurance recommendations and outline

Analysis of Maintenance Service Contracts for Dump Trucks Used in Mining Industry with Simulation Approach

Science.gov (United States)

Dymasius, A.; Wangsaputra, R.; Iskandar, B. P.

2016-02-01

A mining company needs high availability of dump trucks used to haul mining materials. As a result, an effective maintenance action is required to keep the dump trucks in a good condition and hence reducing failure and downtime of the dump trucks. To carry out maintenance in-house requires a high intensive maintenance facility and high skilled maintenance specialists. Often, outsourcing maintenance is an economic option for the company. An external agent takes a proactive action with offering some maintenance contract options to the owner. The decision problem for the owner is to decide the best option and for the agent is to determine the optimal price for each option offered. A non-cooperative game-theory is used to formulate the decision problems for the owner and the agent. We consider that failure pattern of each truck follows a non-homogeneous Poisson process (NHPP) and a queueing theory with multiple servers is used to estimate the downtime. As it involves high complexity to model downtime using a queueing theory, then in this paper we use a simulation method. Furthermore, we conduct experiment to seek for the best number of maintenance facilities (servers) which minimises maintenance and penalty costs incurred to the agent.

Effects of Attentional Focus and Age on Suprapostural Task Performance and Postural Control

Science.gov (United States)

McNevin, Nancy; Weir, Patricia; Quinn, Tiffany

2013-01-01

Purpose: Suprapostural task performance (manual tracking) and postural control (sway and frequency) were examined as a function of attentional focus, age, and tracking difficulty. Given the performance benefits often found under external focus conditions, it was hypothesized that external focus instructions would promote superior tracking and…

Classification of EEG signals to identify variations in attention during motor task execution.

Science.gov (United States)

Aliakbaryhosseinabadi, Susan; Kamavuako, Ernest Nlandu; Jiang, Ning; Farina, Dario; Mrachacz-Kersting, Natalie

2017-06-01

Brain-computer interface (BCI) systems in neuro-rehabilitation use brain signals to control external devices. User status such as attention affects BCI performance; thus detecting the user's attention drift due to internal or external factors is essential for high detection accuracy. An auditory oddball task was applied to divert the users' attention during a simple ankle dorsiflexion movement. Electroencephalogram signals were recorded from eighteen channels. Temporal and time-frequency features were projected to a lower dimension space and used to analyze the effect of two attention levels on motor tasks in each participant. Then, a global feature distribution was constructed with the projected time-frequency features of all participants from all channels and applied for attention classification during motor movement execution. Time-frequency features led to significantly better classification results with respect to the temporal features, particularly for electrodes located over the motor cortex. Motor cortex channels had a higher accuracy in comparison to other channels in the global discrimination of attention level. Previous methods have used the attention to a task to drive external devices, such as the P300 speller. However, here we focus for the first time on the effect of attention drift while performing a motor task. It is possible to explore user's attention variation when performing motor tasks in synchronous BCI systems with time-frequency features. This is the first step towards an adaptive real-time BCI with an integrated function to reveal attention shifts from the motor task. Copyright © 2017 Elsevier B.V. All rights reserved.

Age-related Multiscale Changes in Brain Signal Variability in Pre-task versus Post-task Resting-state EEG.

Science.gov (United States)

Wang, Hongye; McIntosh, Anthony R; Kovacevic, Natasa; Karachalios, Maria; Protzner, Andrea B

2016-07-01

Recent empirical work suggests that, during healthy aging, the variability of network dynamics changes during task performance. Such variability appears to reflect the spontaneous formation and dissolution of different functional networks. We sought to extend these observations into resting-state dynamics. We recorded EEG in young, middle-aged, and older adults during a "rest-task-rest" design and investigated if aging modifies the interaction between resting-state activity and external stimulus-induced activity. Using multiscale entropy as our measure of variability, we found that, with increasing age, resting-state dynamics shifts from distributed to more local neural processing, especially at posterior sources. In the young group, resting-state dynamics also changed from pre- to post-task, where fine-scale entropy increased in task-positive regions and coarse-scale entropy increased in the posterior cingulate, a key region associated with the default mode network. Lastly, pre- and post-task resting-state dynamics were linked to performance on the intervening task for all age groups, but this relationship became weaker with increasing age. Our results suggest that age-related changes in resting-state dynamics occur across different spatial and temporal scales and have consequences for information processing capacity.

The advantages of reliability centered maintenance for standby safety systems

International Nuclear Information System (INIS)

Dam, R.F.; Ayazzudin, S.; Nickerson, J.H.; DeLong, A.I.

2002-01-01

predictive monitoring. The testing in this strategy is part of an effort to ensure that the desired function is not only available today, but will be available tomorrow as well. This paper considers the application of a streamlined form of RCM to the Emergency Core Cooling (ECC) and Standby Generator (SG) Systems of a CANDU plant. Recently completed studies provide useful insight into the important value added of the systematic assessment approach (using RCM techniques) for these standby safety systems. In the case of RCM analysis performed on the Emergency Core Cooling (ECC) System of Point Lepreau Nuclear Power Generating Station (PLGS), it was found that 60% of the current maintenance tasks are testing (functional, stroke, logic, and annunciation tests). Similarly, the SGs have 50% of the maintenance tasks associated with testing. The paper considers how the results of the RCM analysis demonstrate that the analysis can be used to assist in the optimization of the testing program dictated by reliability while also taking better advantage of the testing through condition monitoring and predictive maintenance techniques. Further, the results illustrate the importance of identifying and linking the different plant activities within a well integrated plant culture. (author)

Application of declarative modeling approaches for external events

International Nuclear Information System (INIS)

Anoba, R.C.

2005-01-01

Probabilistic Safety Assessments (PSAs) are increasingly being used as a tool for supporting the acceptability of design, procurement, construction, operation, and maintenance activities at Nuclear Power Plants. Since the issuance of Generic Letter 88-20 and subsequent IPE/IPEEE assessments, the NRC has issued several Regulatory Guides such as RG 1.174 to describe the use of PSA in risk-informed regulation activities. Most PSA have the capability to address internal events including internal floods. As the more demands are being placed for using the PSA to support risk-informed applications, there has been a growing need to integrate other eternal events (Seismic, Fire, etc.) into the logic models. Most external events involve spatial dependencies and usually impact the logic models at the component level. Therefore, manual insertion of external events impacts into a complex integrated fault tree model may be too cumbersome for routine uses of the PSA. Within the past year, a declarative modeling approach has been developed to automate the injection of external events into the PSA. The intent of this paper is to introduce the concept of declarative modeling in the context of external event applications. A declarative modeling approach involves the definition of rules for injection of external event impacts into the fault tree logic. A software tool such as the EPRI's XInit program can be used to interpret the pre-defined rules and automatically inject external event elements into the PSA. The injection process can easily be repeated, as required, to address plant changes, sensitivity issues, changes in boundary conditions, etc. External event elements may include fire initiating events, seismic initiating events, seismic fragilities, fire-induced hot short events, special human failure events, etc. This approach has been applied at a number of US nuclear power plants including a nuclear power plant in Romania. (authors)

Ranking procedure on maintenance tasks for monitoring of embankment dams

International Nuclear Information System (INIS)

Andersen, G.R.; Bouvier, C.; Back, W.E.

1999-01-01

A multistep strategy for the prioritization of maintenance and repair funds for the monitoring of embankment dams is proposed wherein the most important device in the worst condition is preferred. The strategy involves determining the importance of each device (in terms of dam safety) and measuring its condition through field inspections. A condition definition for each device is developed in terms of its ability to function optimally in its diagnostic role. Relative importance of the monitoring devices is defined in terms of diagnostic value and proceeds by considering: (1) the failure modes and their conditional probabilities; (2) adverse conditions and their conditional probabilities; (3) indicators that provide information on these adverse conditions and their relative diagnostic value; and (4) monitoring devices that are used to assess the presence of the indicators and their relative diagnostic value. A panel of dam safety experts is used to answer the questions necessary to implement this methodology through a process of expert elicitation. An interactive DOS-based C++ computer program has been developed to assist in the expert elicitation necessary to implement this methodology

Design and construction of an in-pipe robot for inspection and maintenance

KAUST Repository

Sibai, Fadi N.

2012-12-01

Inspection and maintenance of aging pipelines is crucial to the reliable and continued distribution of hydrocarbons. In this paper, we describe the design and construction of a robotic platform for inspection and minor maintenance of pipelines. The 7.5 kg robotic platform was demonstrated to move straight inside 12″ to 16″ diameter pipes in a forward or backward direction, and either horizontally or vertically. The experimental robotic platform has three sets of two wheels, and three driving motors. The equations governing the mechanical frame\\'s component sizes are presented and the robotic frame component dimensions derived. The paper also discusses the construction and testing of the robot. Future work includes adding sensors, controls for turning, a microcontroller board, and a robotic arm for performing maintenance tasks. © 2012 IEEE.

Design and construction of an in-pipe robot for inspection and maintenance

KAUST Repository

Sibai, Fadi N.; Sayegh, Amer Ahmed; Al-Taie, Ihsan

2012-01-01

Inspection and maintenance of aging pipelines is crucial to the reliable and continued distribution of hydrocarbons. In this paper, we describe the design and construction of a robotic platform for inspection and minor maintenance of pipelines. The 7.5 kg robotic platform was demonstrated to move straight inside 12″ to 16″ diameter pipes in a forward or backward direction, and either horizontally or vertically. The experimental robotic platform has three sets of two wheels, and three driving motors. The equations governing the mechanical frame's component sizes are presented and the robotic frame component dimensions derived. The paper also discusses the construction and testing of the robot. Future work includes adding sensors, controls for turning, a microcontroller board, and a robotic arm for performing maintenance tasks. © 2012 IEEE.

Status of the reliability centered maintenance program at Ontario Hydro's Bruce 'A' Nuclear Division

International Nuclear Information System (INIS)

Khan, I.

1995-01-01

Bruce A started a preventive maintenance (PM) quality improvement program in August of 1991. This initiative was taken to address the concerns expressed by the AECB and the Peer Audits finding. The concerns were on the quality of the Bruce A PM Program and its execution in the field. Reliability Centered Maintenance (RCM) analysis was selected as the PM program quality improvement and optimization technique. Therefore, RCM became a key component of Bruce A's Integrated PM program and maintenance strategy. As a result of RCM implementation, and improvements in the work planning and scheduling process, Bruce A is seeing downward trends in the corrective maintenance work load, maintenance preventable forced outages, overdue/missed PM tasks and corrective maintenance backlog. Control Room Operators have reported observing an improvement in systems and equipment response to transients. Other benefits include a documented, controlled and traceable PM program. In addition, the team approach required by RCM has started to improve staff confidence in the PM program which, in turn, is improving the compliance with the PM program. (author)

Evaluation of implementation of municipal roads’ maintenance plans in Palestine: A pilot case study

Directory of Open Access Journals (Sweden)

Amjad Issa

2017-09-01

Full Text Available The recent preparation of the Operation and Maintenance (O&M Manual for Palestinian municipalities is an important step to guide them towards preparing and implementing their O&M priority-based plans, considering scare resources. During the course of preparation of the Manual, the proposed procedures were applied at ten pilot municipalities. This study aims to explore the outcome of the implementation of the 2014 O&M road maintenance plans at these municipalities. To achieve this, analysis of the outcome of a questionnaire designed to collect relevant information from these municipalities was conducted. The results show that seven of the targeted municipalities used the prioritization criteria proposed in the O&M Manual. Despite that the remaining municipalities had the liberty to slightly change the relative weight of the indicators, sensitivity analysis was conducted and indicated robustness of the indicators. The average percentage of roads’ lengths of the actually maintained to the planned was 35%, suggesting that the plans were ambitious and need to be more rational. Most of the allocated funds for road maintenance came from the municipalities own budgets, indicating need to have more financing by the government to ensure the integrity of the municipal road infrastructure assets. The results also indicated that 95% of the maintenance works were executed through external contracts, and that the municipalities need to be supported and equipped to conduct the basic road maintenance works. Keywords: Road maintenance plans, Maintenance prioritization, Municipal roads’ maintenance, Maintenance plans evaluation, Palestine

Cognitive impairment in methadone maintenance patients.

Science.gov (United States)

Mintzer, Miriam Z; Stitzer, Maxine L

2002-06-01

Few well-controlled studies have examined psychomotor and cognitive performance in methadone maintenance patients (MMP). In the present study, performance of 18 opioid-dependent MMP was evaluated relative to that of 21 control participants without substance abuse histories. The MMP and control groups were balanced with respect to gender, race, age, years of education, current employment status, current reading level, and estimated IQ score. Recent drug abstinence was verified by urine testing. Participants with a urine screen positive for benzodiazepines or a breathalyzer test positive for alcohol prior to performance testing were excluded. To avoid testing under conditions of acute heroin or cocaine intoxication, but without testing under conditions of acute withdrawal, participants with current use of heroin or cocaine were only required to abstain for 24 h prior to performance testing. MMP exhibited impairment relative to controls in psychomotor speed (digit symbol substitution and trail-making tests), working memory (two-back task), decision making (gambling task), and metamemory (confidence ratings on a recognition memory test); results also suggested possible impairment in inhibitory mechanisms (Stroop color-word paradigm). MMP did not exhibit impairment in time estimation, conceptual flexibility or long-term memory. The wide range of impaired functions is striking, and may have important implications for daily functioning in MMP. Further research is necessary to determine the clinical significance of the impairments in laboratory-based tests for daily performance in the natural environment, as well as to differentiate impairments due to acute methadone dosing, chronic methadone maintenance, chronic poly-drug abuse, and other factors. Copyright 2002 Elsevier Science Irealnd Ltd.

Comparison of genetic algorithm and harmony search for generator maintenance scheduling

International Nuclear Information System (INIS)

Khan, L.; Mumtaz, S.; Khattak, A.

2012-01-01

GMS (Generator Maintenance Scheduling) ranks very high in decision making of power generation management. Generators maintenance schedule decides the time period of maintenance tasks and a reliable reserve margin is also maintained during this time period. In this paper, a comparison of GA (Genetic Algorithm) and US (Harmony Search) algorithm is presented to solve generators maintenance scheduling problem for WAPDA (Water And Power Development Authority) Pakistan. GA is a search procedure, which is used in search problems to compute exact and optimized solution. GA is considered as global search heuristic technique. HS algorithm is quite efficient, because the convergence rate of this algorithm is very fast. HS algorithm is based on the concept of music improvisation process of searching for a perfect state of harmony. The two algorithms generate feasible and optimal solutions and overcome the limitations of the conventional methods including extensive computational effort, which increases exponentially as the size of the problem increases. The proposed methods are tested, validated and compared on the WAPDA electric system. (author)

Maintenance of relational information in working memory leads to suppression of the sensory cortex.

Science.gov (United States)

Ikkai, Akiko; Blacker, Kara J; Lakshmanan, Balaji M; Ewen, Joshua B; Courtney, Susan M

2014-10-15

Working memory (WM) for sensory-based information about individual objects and their locations appears to involve interactions between lateral prefrontal and sensory cortexes. The mechanisms and representations for maintenance of more abstract, nonsensory information in WM are unknown, particularly whether such actively maintained information can become independent of the sensory information from which it was derived. Previous studies of WM for individual visual items found increased electroencephalogram (EEG) alpha (8-13 Hz) power over posterior electrode sites, which appears to correspond to the suppression of cortical areas that represent irrelevant sensory information. Here, we recorded EEG while participants performed a visual WM task that involved maintaining either concrete spatial coordinates or abstract relational information. Maintenance of relational information resulted in higher alpha power in posterior electrodes. Furthermore, lateralization of alpha power due to a covert shift of attention to one visual hemifield was marginally weaker during storage of relational information than during storage of concrete information. These results suggest that abstract relational information is maintained in WM differently from concrete, sensory representations and that during maintenance of abstract information, posterior sensory regions become task irrelevant and are thus suppressed. Copyright © 2014 the American Physiological Society.

Robots take a hand in inspection, maintenance and repair

International Nuclear Information System (INIS)

Cruickshank, A.

1985-01-01

In the search for better economic performance through higher availability, utilities are beginning to look with interest at the uses of robotics. However, while some routine surveillance jobs may be amenable to existing commercial robot technology, most maintenance and repair tasks are not. A lot of work still needs to be done to develop robotic devices that can be employed effectively in the sometimes congested and inaccessible environments inside containments. (author)

Robots take a hand in inspection, maintenance and repair

Energy Technology Data Exchange (ETDEWEB)

Cruickshank, A

1985-04-01

In the search for better economic performance through higher availability, utilities are beginning to look with interest at the uses of robotics. However, while some routine surveillance jobs may be amenable to existing commercial robot technology, most maintenance and repair tasks are not. A lot of work still needs to be done to develop robotic devices that can be employed effectively in the sometimes congested and inaccessible environments inside containments.

Reliability-centered maintenance for ground-based large optical telescopes and radio antenna arrays

Science.gov (United States)

Marchiori, G.; Formentin, F.; Rampini, F.

2014-07-01

In the last years, EIE GROUP has been more and more involved in large optical telescopes and radio antennas array projects. In this frame, the paper describes a fundamental aspect of the Logistic Support Analysis (LSA) process, that is the application of the Reliability-Centered Maintenance (RCM) methodology for the generation of maintenance plans for ground-based large optical telescopes and radio antennas arrays. This helps maintenance engineers to make sure that the telescopes continue to work properly, doing what their users require them to do in their present operating conditions. The main objective of the RCM process is to establish the complete maintenance regime, with the safe minimum required maintenance, carried out without any risk to personnel, telescope and subsystems. At the same time, a correct application of the RCM allows to increase the cost effectiveness, telescope uptime and items availability, and to provide greater understanding of the level of risk that the organization is managing. At the same time, engineers shall make a great effort since the initial phase of the project to obtain a telescope requiring easy maintenance activities and simple replacement of the major assemblies, taking special care on the accesses design and items location, implementation and design of special lifting equipment and handling devices for the heavy items. This maintenance engineering framework is based on seven points, which lead to the main steps of the RCM program. The initial steps of the RCM process consist of: system selection and data collection (MTBF, MTTR, etc.), definition of system boundaries and operating context, telescope description with the use of functional block diagrams, and the running of a FMECA to address the dominant causes of equipment failure and to lay down the Critical Items List. In the second part of the process the RCM logic is applied, which helps to determine the appropriate maintenance tasks for each identified failure mode. Once

Familiarity and Within-Person Facial Variability: The Importance of the Internal and External Features.

Science.gov (United States)

Kramer, Robin S S; Manesi, Zoi; Towler, Alice; Reynolds, Michael G; Burton, A Mike

2018-01-01

As faces become familiar, we come to rely more on their internal features for recognition and matching tasks. Here, we assess whether this same pattern is also observed for a card sorting task. Participants sorted photos showing either the full face, only the internal features, or only the external features into multiple piles, one pile per identity. In Experiments 1 and 2, we showed the standard advantage for familiar faces-sorting was more accurate and showed very few errors in comparison with unfamiliar faces. However, for both familiar and unfamiliar faces, sorting was less accurate for external features and equivalent for internal and full faces. In Experiment 3, we asked whether external features can ever be used to make an accurate sort. Using familiar faces and instructions on the number of identities present, we nevertheless found worse performance for the external in comparison with the internal features, suggesting that less identity information was available in the former. Taken together, we show that full faces and internal features are similarly informative with regard to identity. In comparison, external features contain less identity information and produce worse card sorting performance. This research extends current thinking on the shift in focus, both in attention and importance, toward the internal features and away from the external features as familiarity with a face increases.