Maintenance Workload Research Articles

Modularization for the Cell Ontology

AbstractOne of the premises of the OBO Foundry is that development of an orthogonal set of ontologies will increase domain expert contributions and logical interoperability, and decrease maintenance workload. For these reasons, the Cell Ontology (CL) is being re-engineered. This process requires the extraction of sub-modules from existing OBO ontologies, which presents a number of practical engineering challenges. These extracted modules may be intended to cover a narrow or a broad set of species. In addition, applications and resources that make use of the Cell Ontology have particular modularization requirements, such as the ability to extract custom subsets or unions of the Cell Ontology with other OBO ontologies. These extracted modules may be intended to cover a narrow or a broad set of species, which presents unique complications.We discuss some of these requirements, and present our progress towards a customizable simple-to-use modularization tool that leverages existing OWL-based tools and opens up their use for the CL and other ontologies.

Parametric Models for Aircraft Engine Removals Resulting from Foreign Object Damage

AbstractAn earlier nonparametric statistical study of GE F414 engine removals from operational F/A‐18 aircraft in US Navy service provided insights into the lifetime patterns of engine removals for various causes. Inspection of the estimated hazard function for engine removals for foreign object damage (FOD) suggested that a parametric analysis using Erlang distributions might be fruitful, bolstered by a hypothesized relevance to the maintenance procedures governing engine removals for this cause, and their outcomes. The objective was both a better model to forecast engine removals and to provide insight into the number of FOD incidents it took to drive an engine removal. Gamma and Erlang distributions did better fit the removals data and provide a tool for predicting engine removals, aircraft availability impact, and the resultant maintenance workload. A parametric model using a cascade of Erlang functions was developed to simulate the combined FOD/line maintenance process, which provides insight into the outcomes expected under reasonable simplifying assumptions. This model predicts that the key research issue, the probability that a typical FOD event prompts a removal, cannot be estimated from engine removals data alone. Field data must be collected to gain understanding of the underlying frequency of FOD and the utility of the present inspection criteria.

How to Improve the Reliability of Wind Turbines

According to the failure of wind turbines in operation, the failure cause and phenomenon of wind turbines is analyzed, combined with the reliability of wind turbine subsystems, measures aiming at cooperation parts and purchased parts are proposed, the reliability of the whole wind turbines is improved in a certain extent. At the same time, condition monitoring system can carry through the early detecting and diagnosing to potential component failure maintain. Besides, automatic lubrication system can realize accurate and timeliness lubrication, also can reduce maintenance workload, preserve correct lubrication and smooth running of all parts.

Hotel engineering facilities: A case study of maintenance performance

Many hotels are using computerised maintenance management systems (CMMS) to organize building and facility maintenance works. The data recorded by a CMMS are useful information to assessment of maintenance performance but few have paid attention to this application. The findings of a pilot case study conducted based on a 618-room hotel in Hong Kong, as reported in this paper, include how the hotel's CMMS was utilized to facilitate maintenance work organization and the analyses of the CMMS records and associated documentary information for a 12-month period. The study revealed that the maintenance workload was dominated by electrical installations, and the guestrooms demanded for far more maintenance works than the other areas. Significant correlation was found between equipment downtime and amount of maintenance work orders. A range of performance curves and indicators which is useful for assessing maintenance performance of hotel engineering facilities is also presented.

A New Roller Conveyor Driven by Linear Motor

To solve technical problems of current roller conveyor, such as big volume, complex structure and heavy maintenance workload, a new roller conveyor has been researched by adopting advanced technology of three-phase A.C linear motor. It has no intermediate transmission units that exist in the conventional roller conveyor, and is a new form structure of the conveyor. The device consists mainly of rollers and linear motors. The roller serves as driving and load-bearing mechanism, and as the rotor of linear motor, too. In the process of operation, with rollers served as the carriers, the friction force between rollers and objects transmits the motion consummately to achieve the goal of transportation. This new conveyor can completely replace the current various types of roller conveyor with such features as simple structure, low failure rate and cost.

Maintainability risks of condominiums in Sri Lanka

PurposeWith increased architectural, design and functional requirements and complexities, maintaining a modern building can easily become a costly affair. There is much evidence in the literature review as well as from the factual data, showing the significant increase of the maintenance budget in the recent past. This is due to the fact that, these complexities eventually generate many deficiencies and difficulties and, in turn, creates a tremendous maintenance workload and an undue budget. Therefore, the purpose of this paper is to discuss factors related to such issues in the form of risks involved in the maintainability of buildings and further, explore several strategies and industry actions at the industry level to resolve this burning problem. This paper is focused to address the condominium properties.Design/methodology/approachThis approach of investigation of the risk factors was based on exploring the causes of existing defects and problems, which tend to lower the maintainability. Existing literature, site observations/interviews and questionnaire surveys were used to gather the required data.FindingsThere are 13 number of critical maintainability problems, 43 respective factors as “maintainability risk” factors and 12 subsequent industry actions for better maintainability, in the findings. In addition, nine maintainability strategies are explored based on the relevant risk conditions to enhance the maintainability at the organizational/project level and three industry motivators are extracted from the relevant industry actions. A simplified framework for maintainability is proposed based on the strategies and the industry actions.Research limitations/implicationsThe data collection has to be limited to the Colombo metropolitan region due to limited resources.Originality/valueThe paper provides useful information to the designers, clients, facilities managers/maintenance managers and users, on maintainability issues related to condominiums. This information highlights the important risk conditions, strategies and industry motivators in order to minimize these problems. These findings may provide an opportunity to promote “highly maintainable buildings for the future”.

Development and Evaluation of a Low-Cost and High-Capacity DICOM Image Data Storage System for Research

Thin-slice CT data, useful for clinical diagnosis and research, is now widely available but is typically discarded in many institutions, after a short period of time due to data storage capacity limitations. We designed and built a low-cost high-capacity Digital Imaging and COmmunication in Medicine (DICOM) storage system able to store thin-slice image data for years, using off-the-shelf consumer hardware components, such as a Macintosh computer, a Windows PC, and network-attached storage units. "Ordinary" hierarchical file systems, instead of a centralized data management system such as relational database, were adopted to manage patient DICOM files by arranging them in directories enabling quick and easy access to the DICOM files of each study by following the directory trees with Windows Explorer via study date and patient ID. Software used for this system was open-source OsiriX and additional programs we developed ourselves, both of which were freely available via the Internet. The initial cost of this system was about $3,600 with an incremental storage cost of about $900 per 1 terabyte (TB). This system has been running since 7th Feb 2008 with the data stored increasing at the rate of about 1.3 TB per month. Total data stored was 21.3 TB on 23rd June 2009. The maintenance workload was found to be about 30 to 60 min once every 2 weeks. In conclusion, this newly developed DICOM storage system is useful for research due to its cost-effectiveness, enormous capacity, high scalability, sufficient reliability, and easy data access.

Evaluation and prediction of on‐line maintenance workload in nuclear power plants

AbstractThis study evaluates engineers' mental workload while maintaining digital systems in nuclear power plants (NPPs). First, according to the factors affecting the mental workload, a questionnaire was designed to evaluate the mental workload of maintenance engineers at the Second NPP in Taiwan. Then 16 maintenance engineers from the Second NPP participated in the experiment survey. The results indicated that the mental workload was lower in maintaining digital systems than that in analog systems. Finally, a mental workload model based on the neural network technique was established to predict the mental workload of maintenance engineers in maintaining digital systems. Through predicting mental workload, the manager can organize the human resources for each daily task to sustain the appropriate mental workload as well as improve maintenance performance. © 2008 Wiley Periodicals, Inc.

Long-term complications of bone-anchored hearing aids: a 14-year experience

To report cases of long-term surgical complications, implant failure and revision surgery, within a large bone-anchored hearing aid programme. Retrospective, case-cohort study. Tertiary referral centre. One hundred and sixty-five adults and children who had undergone a total of 177 bone-anchored hearing aid implantations. Diagnosis and explanation of adverse events and device failure. Operative complications and survival analysis, surgical challenges related to revisions, and causes of failure. Twenty-one per cent of patients (3.4 per cent of those observed) suffered from skin reactions; this rate did not increase over time. Seventeen per cent had loss of osseointegration at a median interval of 6.3 months. Loss of osseointegration was observed more frequently in patients with a 3 mm compared with a 4 mm fixture (p < 0.001). Intra-operatively, the only complication was bleeding, occurring in 3 per cent of patients. Post-operative complications included: primary bleeding (2 per cent); severe skin reactions requiring intravenous antibiotics, cautery or grafting (8 per cent); thickening or overgrowth of skin requiring excision (8 per cent); failure of osseointegration requiring a new fixture (18 per cent); and graft necrosis requiring revision (1 per cent). In two patients, it was necessary to explore the area to remove overgrowth of bone. In 16 patients (10 per cent), the bone-anchored hearing aid had to be abandoned due to failure of osseointegration (n = 4), dissatisfaction with the aid (n = 6), intolerable pain (n = 4), hair growth around the abutment (n = 1) or recurrent infections (n = 1). In 12 of these patients, the bone-anchored hearing aid was removed surgically. Overall, 57 patients (34 per cent) underwent revision surgery. Awareness of complications is becoming increasingly important in bone-anchored hearing aid programme. A substantial workload of device maintenance should be anticipated, and patients should be appropriately counselled beforehand. Ninety per cent of our patients chose to persevere with this form of hearing rehabilitation.

ABCGrid: Application for Bioinformatics Computing Grid

We have developed a package named Application for Bioinformatics Computing Grid (ABCGrid). ABCGrid was designed for biology laboratories to use heterogeneous computing resources and access bioinformatics applications from one master node. ABCGrid is very easy to install and maintain at the premise of robustness and high performance. We implement a mechanism to install and update all applications and databases in worker nodes automatically to reduce the workload of manual maintenance. We use a backup task method and self-adaptive job dispatch approach to improve performance. Currently, ABCGrid integrates NCBI_BLAST, Hmmpfam and CE, running on a number of computing platforms including UNIX/Linux, Windows and Mac OS X. The source code, executables and documents can be downloaded from http://abcgrid.cbi.pku.edu.cn

Determination of preventive maintenance periodicities of standby devices

This article presents a statistical approach of analysis and decision that uses reliability techniques to define the best periodicity for preventive maintenance of power system protective relays. Relays are standby devices and may stay in the hidden failure state when they are not working. This state of failure generates difficulties in the determination of preventive maintenance periodicities. A case study presented in this work deals specifically with the reliability of the transmission and distribution system protective relays of CEMIG (the state owned Electrical Power Company of Minas Gerais, Brazil). Preventive maintenance data of protective relays obtained during a 4-year period were used in the proposed method. The choice of the periodicities, distinguished by groups of similar relay and voltage operation levels of the protected systems, is made according to the failure risk level that the company is willing to take. The main result obtained by using this method is a substantial reduction of 62% in the amount of preventive maintenance work load for the relays of the distribution system.

Nomencurator: a nomenclatural history model to handle multiple taxonomic views

Evolutionary studies are generating increasing numbers of phylogenies which, in turn, sometimes result in changes to hierarchical organization and therefore changes in taxonomic nomenclature. A three-layered data model for a nomenclature database has been developed in order to elucidate the information structure in nomenclature and as a means to organize and manage a large, dynamic knowledge-base. In contrast to most other taxonomic databases, the model is publication-oriented rather than taxon-oriented and dynamic rather than static, in order to mimic the processes that taxonomists use naturally. The three-layered structure requires data integrity localized to each publication, instead of global data integrity, which relaxes constraints common to taxonomic databases and permits multiple taxonomic opinions: taxon names are made available as metadata within the model. Its prototype implementation, written in C ++, has an autonomous self-identification mechanism to avoid spurious data-inflation in a publication-oriented data model. Self-identification is also desirable for distributed implementations of the nomenclature database. Publication-oriented design also will make maintenance easier than for taxon-oriented databases, much of the maintenance workload being amenable to automation. The three-layered data model was designed for use by taxonomists, but is also able to provide concise, reduced expression for non-experts required in biodiversity research, for example.

Nomencurator: a nomenclatural history model to handle multiple taxonomic views

Evolutionary studies are generating increasing numbers of phylogenies which, in turn, sometimes result in changes to hierarchical organization and therefore changes in taxonomic nomenclature. A three-layered data model for a nomenclature database has been developed in order to elucidate the information structure in nomenclature and as a means to organize and manage a large, dynamic knowledge-base. In contrast to most other taxonomic databases, the model is publication-oriented rather than taxon-oriented and dynamic rather than static, in order to mimic the processes that taxonomists use naturally. The three-layered structure requires data integrity localized to each publication, instead of global data integrity, which relaxes constraints common to taxonomic databases and permits multiple taxonomic opinions: taxon names are made available as metadata within the model. Its prototype implementation, written in C++, has an autonomous self-identification mechanism to avoid spurious data-inflation in a publication-oriented data model. Self-identification is also desirable for distributed implementations of the nomenclature database. Publication-oriented design also will make maintenance easier than for taxon-oriented databases, much of the maintenance workload being amenable to automation. The three-layered data model was designed for use by taxonomists, but is also able to provide concise, reduced expression for non-experts required in biodiversity research, for example.

Analyzing human error in aircraft ground damage incidents

Ground damage incidents (incidents in which airline personnel cause damage to an aircraft on the ground) occur as airline personnel are working on, or around, an aircraft on the ground, either on the ramp or at a maintenance facility. Each incident can be quite costly to the airline, with costs both tangible (repair costs and lost revenue) and intangible (passenger inconvenience, increased maintenance workload). Thus, airlines have a financial incentive to reduce the number of ground damage incidents that occur. One of the airline's most difficult tasks has been to utilize the information collected in their existing error reporting systems to determine the common latent failures which contribute to typical ground damage incidents. In this study, 130 ground damage incidents from a major airline were reviewed to determine the active and latent failures. Twelve distinct hazard patterns (representing the active failures) were identified, with three hazard patterns accounting for 81% of all ground damage incidents. Nine major latent failures were identified, and the relationships between the hazard patterns and latent failures were examined in depth. This type of analysis allows the latent failures common to different hazard patterns to be identified, and provides a means for developing focused intervention strategies to prevent future ground damage. Relevance to industry Airlines have generally had a difficult time analyzing reports of human error to make improvements in their maintenance systems. This study provides a methodology that allows reports of human error to be analyzed, and interventions developed based on the results of the analysis. The methodology would also be applicable to, and useful in, other industries.

Development of a computerized equipment management program at Children's Hospital "Bambino Gesù" of Rome, Italy.

The main activities of the Clinical Engineering Service at the Children's Hospital "Bambino Gesù" of Rome, Italy and the computerized system developed in-house for electromedical equipment management are described here. The approach recently adopted and implemented for an objective cost/benefit evaluation of the equipment installed at the hospital is also described. The program outputs appear to be effective tools, both in evaluating maintenance costs and workload increases from new equipment installations and, more relevantly, in comparing similar equipment from different manufacturers during prepurchase evaluation.

A Supervisory Grid to Understand the Role of the Maintenance Foreman in Process Industries

The maintenance foreman occupies a critical role in a process industry. He is at the focus of two strong, sometimes conflicting, sets of influences, top-down from senior management, and bottom-up from the maintenance workload and tradesmen. It is a complex and ambiguous role both to the foremen themselves and to their managers. This paper explains why such ambiguity is likely to arise. A novel matrix is developed comprising four key interrelated domains of the maintenance foreman's role, and into which all the duties he is normally expected to perform can be categorized. The resulting supervisory grid clarifies both the wide scope of these duties, and identifies the two differing personal characteristics which maintenance foremen require in order to succeed in performing them. The grid has many practical applications. In particular it provides a sound basis for examining the new specialist and diversified roles for maintenance foremen which are now emerging in the process industry.

An expert system to estimate highway pavement routine maintenance work load

Abstract An expert system was developed that can be used to estimate highway pavement routine maintenance needs at a subdistrict level. The knowledge base was prepared by extracting the experience and judgement of unit foremen. The expert system is written in LISP and is interactive in nature. It requires the user to input information about the general features of the highway section and the observed distress data. The package gives explicit recommendations as to the type and amount of activities to be performed along with the information on expected costs.

The effective maintenance of lighting installations in a large organisation

The Department is responsible for the design, installation and subsequent maintenance of electrical services, including lighting, in approximately 3,500 premises including major public buildings. For the maintenance workload to be carried out effectively and within appropriate financial limits maintenance procedures and standards have to be established although, of necessity, standards will vary. The quality of the original design and installation work will influence the maintenance standards and ease of access and reliability are other factors that affect the level of maintenance achieved. The implications of the Health and Safety at Work Act and the need to conserve energy also have a significant impact on maintenance work.

An Automated Procedure to Establish Workzone Boundaries for Air Force Facilities Maintenance Operations

The problem of balancing maintenance workloads among geographical workzones on an air force base is discussed. An algorithm is presented which assigns facilities to workzones such that facilities assigned to the same workzone satisfy two conditions:

IS AUTOMATION THE MAGIC POTION FOR MANNING PROBLEMS?

ABSTRACTThis paper examines the recent experience in the UNITED STATES NAVY where automation has been introduced into new ship designs. While other attributes are recognized in the introduction of automated shipboard systems, such as the ability to respond more quickly in combat situations, this paper focuses on the effects of automation upon ship manpower requirements. Specific examples show that expected reductions in manning were not achieved in recent ship designs where automation was incorporated for that purpose. While the use of shipboard automation is not without its critics, the U.S. Fleet appears to have accepted the concept. User feedback addresses the issues of reliability, the provisions for backup systems, the need for better qualified personnel and the concern about maintenance workload. The authors provide specific recommendations for improved guidance to ship designers to more effectively apply automation in the ship design process.