901 resultados para Lean maintenance


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Lean body mass (LBM) and muscle mass remains difficult to quantify in large epidemiological studies due to non-availability of inexpensive methods. We therefore developed anthropometric prediction equations to estimate the LBM and appendicular lean soft tissue (ALST) using dual energy X-ray absorptiometry (DXA) as a reference method. Healthy volunteers (n= 2220; 36% females; age 18-79 y) representing a wide range of body mass index (14-44 kg/m2) participated in this study. Their LBM including ALST was assessed by DXA along with anthropometric measurements. The sample was divided into prediction (60%) and validation (40%) sets. In the prediction set, a number of prediction models were constructed using DXA measured LBM and ALST estimates as dependent variables and a combination of anthropometric indices as independent variables. These equations were cross-validated in the validation set. Simple equations using age, height and weight explained > 90% variation in the LBM and ALST in both men and women. Additional variables (hip and limb circumferences and sum of SFTs) increased the explained variation by 5-8% in the fully adjusted models predicting LBM and ALST. More complex equations using all the above anthropometric variables could predict the DXA measured LBM and ALST accurately as indicated by low standard error of the estimate (LBM: 1.47 kg and 1.63 kg for men and women, respectively) as well as good agreement by Bland Altman analyses. These equations could be a valuable tool in large epidemiological studies assessing these body compartments in Indians and other population groups with similar body composition.

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The E&P sector can learn much about asset maintenance from the space and satellite industry. Practitioners from both the upstream oil and gas industry and the space and satellite sector have repeatedly noted several striking similarities between the two industries over the years, which have in turn resulted in many direct comparisons in the media and industry press. The similarities between the two industries have even resulted in a modest amount of cross-pollinating between the respective supply chains. Because the operating conditions of both industries are so extreme, some oil and gas equipment vendors have occasionally sourced motors and other parts from aerospace contractors. Also, satellites are now being used to assess oil fires, detect subsidence in oil fields, measure oil spills, collect and transmit operational data from oil and gas fields, and monitor the movement of icebergs that might potentially collide with offshore oil and gas installations.

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Lean strategies have been developed to eliminate or reduce waste and thus improve operational efficiency in a manufacturing environment. However, in practice, manufacturers encounter difficulties to select appropriate lean strategies within their resource constraints and to quantitatively evaluate the perceived value of manufacturing waste reduction. This paper presents a methodology developed to quantitatively evaluate the contribution of lean strategies selected to reduce manufacturing wastes within the manufacturers’ resource (time) constraints. A mathematical model has been developed for evaluating the perceived value of lean strategies to manufacturing waste reduction and a step-by-step methodology is provided for selecting appropriate lean strategies to improve the manufacturing performance within their resource constraints. A computer program is developed in MATLAB for finding the optimum solution. With the help of a case study, the proposed methodology and developed model has been validated. A ‘lean strategy-wastes’ correlation matrix has been proposed to establish the relationship between the manufacturing wastes and lean strategies. Using the correlation matrix and applying the proposed methodology and developed mathematical model, authors came out with optimised perceived value of reduction of a manufacturer's wastes by implementing appropriate lean strategies within a manufacturer's resources constraints. Results also demonstrate that the perceived value of reduction of manufacturing wastes can significantly be changed based on policies and product strategy taken by a manufacturer. The proposed methodology can also be used in dynamic situations by changing the input in the programme developed in MATLAB. By identifying appropriate lean strategies for specific manufacturing wastes, a manufacturer can better prioritise implementation efforts and resources to maximise the success of implementing lean strategies in their organisation.

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Roofing tile manufacturing is a mass production process with high operational and inventory wastes and costs. Due to huge operational costs, excessive inventory and wastes, and quality problems, roofing tile manufacturers are trying to implement lean manufacturing practice in their operations in order to remain competitive in an ncreasingly competitive global market. The aim of this research is to evaluate the possibility of reducing the operational and inventory costs of the tile manufacturing process through waste minimization. This paper analyses the current waste situation in a tile manufacturing process and develops current and future value stream mapping for such a process with a view to implementing lean principles in manufacturing. The focus of the approach is on cost reduction by eliminating non-value-added activities.

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Purpose – The purpose of this paper is to develop an effective methodology for implementing lean manufacturing strategies and a leanness evaluation metric using continuous performance measurement (CPM). Design/methodology/approach – Based on five lean principles, a systematic lean implementation methodology for manufacturing organizations has been proposed. A simplified leanness evaluation metric consisting of both efficiency and effectiveness attributes of manufacturing performance has been developed for continuous evaluation of lean implementation. A case study to validate the proposed methodology has been conducted and proposed CPM metric has been used to assess the manufacturing leanness. Findings – Proposed methodology is able to systematically identify manufacturing wastes, select appropriate lean tools, identify relevant performance indicators, achieve significant performance improvement and establish lean culture in the organization. Continuous performance measurement matrices in terms of efficiency and effectiveness are proved to be appropriate methods for continuous evaluation of lean performance. Research limitations/implications – Effectiveness of the method developed has been demonstrated by applying it in a real life assembly process. However, more tests/applications will be necessary to generalize the findings. Practical implications – Results show that applying the methods developed, managers can successfully identify and remove manufacturing wastes from their production processes. By improving process efficiency, they can optimize their resource allocations. Manufacturers now have a validated step by step methodology for successfully implementing lean strategies. Originality/value – According to the authors’ best knowledge, this is the first known study that proposed a systematic lean implementation methodology based on lean principles and continuous improvement techniques. Evaluation of performance improvement by lean strategies is a critical issue. This study develops a simplified leanness evaluation metric considering both efficiency and effectiveness attributes and integrates it with the lean implementation methodology.

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The cost of surgical instrumentation is a major investment for any operating theatre. Repair or premature replacement of instruments is an additional financial burden. Although instrument care, handling, cleaning and sterilisation are usually components of orientation programs for instrument processing personnel, it should also be included in the scrub nurse orientation program. A thorough knowledge of the historical development of instruments; instrument classification and purpose; and careful use and handling will equip the scrub nurse in fulfilling a vital role in preventative maintenance of surgical instrumentation

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For industrial wireless sensor networks, maintaining the routing path for a high packet delivery ratio is one of the key objectives in network operations. It is important to both provide the high data delivery rate at the sink node and guarantee a timely delivery of the data packet at the sink node. Most proactive routing protocols for sensor networks are based on simple periodic updates to distribute the routing information. A faulty link causes packet loss and retransmission at the source until periodic route update packets are issued and the link has been identified as broken. We propose a new proactive route maintenance process where periodic update is backed-up with a secondary layer of local updates repeating with shorter periods for timely discovery of broken links. Proposed route maintenance scheme improves reliability of the network by decreasing the packet loss due to delayed identification of broken links. We show by simulation that proposed mechanism behaves better than the existing popular routing protocols (AODV, AOMDV and DSDV) in terms of end-to-end delay, routing overhead, packet reception ratio.

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In the present study, we examined the associations of early nutrition with adult lean body mass (LBM) and muscle strength in a birth cohort that was established to assess the long-term impact of a nutrition program. Participants (n = 1,446, 32% female) were born near Hyderabad, India, in 29 villages from 1987 to 1990, during which time only intervention villages (n = 15) had a government program that offered balanced protein-calorie supplementation to pregnant women and children. Participants’ LBM and appendicular skeletal muscle mass were measured using dual energy x-ray absorptiometry; grip strength and information on lifestyle indicators, including diet and physical activity level, were also obtained. Ages (mean = 20.3 years) and body mass indexes (weight (kg)/height (m)2; mean = 19.5) of participants in 2 groups were similar. Current dietary energy intake was higher in the intervention group. Unadjusted LBM and grip strength were similar in 2 groups. After adjustment for potential confounders, the intervention group had lower LBM (β = −0.75; P = 0.03), appendicular skeletal muscle mass, and grip strength than did controls, but these differences were small in magnitude (<0.1 standard deviation). Multivariable regression analyses showed that current socioeconomic position, energy intake, and physical activity level had a positive association with adult LBM and muscle strength. This study could not detect a “programming” effect of early nutrition supplementation on adult LBM and muscle strength.

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The double burden of childhood undernutrition and adult-onset adiposity in transitioning societies poses a significant public health challenge. The development of suboptimal lean body mass (LBM) could partly explain the link between these two forms of malnutrition. This review examines the evidence on both the role of nutrition in “developmental programming” of LBM and the nutritional influences that affect LBM throughout the life course. Studies from developing countries assessing the relationship of early nutrition with later LBM provide important insights. Overall, the evidence is consistent in suggesting a positive association of early nutritional status (indicated by birth weight and growth during first 2 years) with LBM in later life. Evidence on the impact of maternal nutritional supplementation during pregnancy on later LBM is inconsistent. In addition, the role of nutrients (protein, zinc, calcium, vitamin D) that can affect LBM throughout the life course is described. Promoting optimal intakes of these important nutrients throughout the life course is important for reducing childhood undernutrition as well as for improving the LBM of adults.

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This study unveils causes of accidents in repair, maintenance, alteration and addition (RMAA) work. RMAA work is playing an increasingly important role in developed societies, including Hong Kong. Safety problems associated with RMAA work in Hong Kong has reached an alarming level. In view of rapid expansion of the RMAA sector and rising proportion of accidents in the construction industry, there is a pressing need to investigate causes of RMAA accidents. Structured interviews were conducted with RMAA contractors to explore causes of accidents in the RMAA sector. A two-round Delphi method with 13 safety experts was subsequently employed to verify the interview findings and rank the relative degree of importance for various causes of accidents. Accidents happen in RMAA work due to intersection of reasons. One of the root causes of accidents in RMAA works is low safety awareness of RMAA workers; however, wider organizational and industrial factors are not negligible. This study sheds light on why accidents happen in the RMAA sector. Only when the factors leading to accidents are identified can effective measures be made.

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Repair, maintenance, minor alteration, and addition work (RMAA) has become more and more important in developed societies, but its safety performance is alarming. For example, RMAA projects accounted for 53.2% of the total construction market and the percentage of RMAA accidents to all construction accidents in the Hong Kong Special Administrative Region (HKSAR) increased considerably in 2007. The RMAA sector has a huge potential for safety improvement. This study aims to explore and evaluate the difficulties of implementing safety practices in RMAA work. The mixed methods approach was adopted, and semistructured interviews and a two-round Delphi survey were conducted for the data collection. Major difficulties were identified, including limited safety resources for small and medium enterprises (SMEs), difficulty in changing the mindset of RMAA workers, and difficulty in performing safety supervision. These obstacles for implementing safety practices in the RMAA sector, if successfully removed, could significantly improve the safety performance of the RMAA sector and the construction industry as a whole.

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Software development settings provide a great opportunity for CSCW researchers to study collaborative work. In this paper, we explore a specific work practice called bug reproduction that is a part of the software bug-fixing process. Bug re-production is a highly collaborative process by which software developers attempt to locally replicate the ‘environment’ within which a bug was originally encountered. Customers, who encounter bugs in their everyday use of systems, play an important role in bug reproduction as they provide useful information to developers, in the form of steps for reproduction, software screenshots, trace logs, and other ways to describe a problem. Bug reproduction, however, poses major hurdles in software maintenance as it is often challenging to replicate the contextual aspects that are at play at the customers’ end. To study the bug reproduction process from a human-centered perspective, we carried out an ethnographic study at a multinational engineering company. Using semi-structured interviews, a questionnaire and half-a-day observation of sixteen software developers working on different software maintenance projects, we studied bug reproduction. In this pa-per, we present a holistic view of bug reproduction practices from a real-world set-ting and discuss implications for designing tools to address the challenges developers face during bug reproduction.

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Safety of repair, maintenance, alteration, and addition (RMAA) works have long been neglected because RMAAworks are often minute and only last for a short period of time. With rising importance of the RMAA sector in many developed societies, safety of RMAA works has begun to draw attention. Many RMAA contracting companies are small- and medium-sized enterprises (SMEs) that do not have comprehensive safety management systems. Existing safety legislation and regulations for new construction sites are not fully applicable to RMAAworks. Instead of relying on explicit and well-established safety systems, tacit safety knowledge plays an extremely important role in RMAA projects. To improve safety of RMAAworks, safety knowledge should be better managed. However, safety knowledge is difficult to capture in RMAA works. This study aims to examine safety management practices of RMAA contracting companies to see how safety knowledge of RMAA projects is managed. Findings show that RMAA contracting companies undertaking large-scale RMAA projects have more initiatives of safety management. Safety management of small-scale RMAA works relies heavily on the motivation of site supervisors and self-regulation of workers. Better tacit knowledge management improves safety performance. To enhance safety capability of RMAA contracting companies, a knowledge sharing culture should be cultivated. The government should provide assistance to SMEs to implement proper safety management practices in small-sized projects. Potentials of applying computer software technology in RMAA projects to capture, store, and retrieve safety information should be explored. Employees should be motivated to share safety knowledge by giving proper recognition to those who are willing to share.

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Purpose The repair, maintenance, minor alteration and addition (RMAA) sector has been expanding in many developed cities. Safety problems of the RMAA sector have attracted the attention of many governments. This study has the objectives of comparing the level of safety climate of workers, supervisors and managers in the RMAA sector; and explaining/ predicting the impact of safety climate on injury occurrence of workers, supervisors and managers. Design/methodology/approach A questionnaire survey was administered to RMAA contracting companies in Hong Kong. Findings When comparing the safety climate perception of workers, supervisors and managers in the RMAA sector, the supervisors group had the lowest mean safety climate score. Results showed that a positive workforce safety attitude and acceptance of safety rules and regulations reduced the workers’ likelihood of having injuries. A reasonable production schedule led to a lower probability of supervisors being injured. Management commitment and effective safety management reduced the probability of managers being injured. Originality/value This study revealed variations of safety climate at the different levels in the organizational hierarchy and their varying influence on safety performance of the RMAA sector. Safety of RMAA works could be improved by promulgating specific safety measures at the different hierarchy levels.

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This study examines fatalities of repair, maintenance, minor alteration, and addition (RMAA) works which occurred in Hong Kong between January 2000 and October 2011. A total of 119 RMAA fatalities were recorded. Particular emphasis was placed on fall from height accidents as they accounted for the vast majority of RMAA fatal accidents for the period. A cluster analysis was conducted on fall from height fatal cases. The cluster analysis clearly identified three groups of fall from height fatalities: (1) bamboo scaffolders aged between 25 and 34 who fell from external wall/facade in the beginning of weekdays; (2) miscellaneous workers aged between 45 and 54 who fell from other/unknown places in the end of weekdays; and (3) manual labour aged between 35 and 44 who fell at floor level/from floor openings in weekends. Unsafe process and improper procedures were the main unsafe condition leading to fatalities whereas safety belt not properly used was the main unsafe action leading to fatalities. Specific safety interventions were recommended for each of these groups to help avoid these fatalities.