960 resultados para Production performance
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The main aim of this research is to demonstrate strategic supplier performance evaluation of a UK-based manufacturing organisation using an integrated analytical framework. Developing long term relationship with strategic suppliers is common in today's industry. However, monitoring suppliers' performance all through the contractual period is important in order to ensure overall supply chain performance. Therefore, client organisations need to measure suppliers' performance dynamically and inform them on improvement measures. Although there are many studies introducing innovative supplier performance evaluation frameworks and empirical researches on identifying criteria for supplier evaluation, little has been reported on detailed application of strategic supplier performance evaluation and its implication on overall performance of organisation. Additionally, majority of the prior studies emphasise on lagging factors (quality, delivery schedule and value/cost) for supplier selection and evaluation. This research proposes both leading (organisational practices, risk management, environmental and social practices) and lagging factors for supplier evaluation and demonstrates a systematic method for identifying those factors with the involvement of relevant stakeholders and process mapping. The contribution of this article is a real-life case-based action research utilising an integrated analytical model that combines quality function deployment and the analytic hierarchy process method for suppliers' performance evaluation. The effectiveness of the method has been demonstrated through number of validations (e.g. focus group, business results, and statistical analysis). Additionally, the study reveals that enhanced supplier performance results positive impact on operational and business performance of client organisation.
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In the world, scientific studies increase day by day and computer programs facilitate the human’s life. Scientists examine the human’s brain’s neural structure and they try to be model in the computer and they give the name of artificial neural network. For this reason, they think to develop more complex problem’s solution. The purpose of this study is to estimate fuel economy of an automobile engine by using artificial neural network (ANN) algorithm. Engine characteristics were simulated by using “Neuro Solution” software. The same data is used in MATLAB to compare the performance of MATLAB is such a problem and show its validity. The cylinder, displacement, power, weight, acceleration and vehicle production year are used as input data and miles per gallon (MPG) are used as target data. An Artificial Neural Network model was developed and 70% of data were used as training data, 15% of data were used as testing data and 15% of data is used as validation data. In creating our model, proper neuron number is carefully selected to increase the speed of the network. Since the problem has a nonlinear structure, multi layer are used in our model.
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As the world’s natural resources dwindle and critical levels of environmental pollution are approached, sustainability becomes a key issue for governments, organisations and individuals. With the consequences of such an issue in mind, this paper introduces a unifying approach to measure the sustainability performance of socio-economic systems based on the interplay between two key variables: essentiality of consumption and environmental impact. This measure attributes to every system a ‘fitness’ value i.e. a quantity that reflects its ability to remain resilient/healthy by avoiding ecological, social and economic collapse as it consumes the available resources. This new measure is tested on a system where there is a limited supply of resources and four basic consumption types. The analysis has theoretical implications as well as practical importance as it can help countries, organisations or even individuals, in finding better ways to measure sustainability performance.
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Tool life is an important factor to be considered during the optimisation of a machining process since cutting parameters can be adjusted to optimise tool changing, reducing cost and time of production. Also the performance of a tool is directly linked to the generated surface roughness and this is important in cases where there are strict surface quality requirements. The prediction of tool life and the resulting surface roughness in milling operations has attracted considerable research efforts. The research reported herein is focused on defining the influence of milling cutting parameters such as cutting speed, feed rate and axial depth of cut, on three major tool performance parameters namely, tool life, material removal and surface roughness. The research is seeking to define methods that will allow the selection of optimal parameters for best tool performance when face milling 416 stainless steel bars. For this study the Taguchi method was applied in a special design of an orthogonal array that allows studying the entire parameter space with only a number of experiments representing savings in cost and time of experiments. The findings were that the cutting speed has the most influence on tool life and surface roughness and very limited influence on material removal. By last tool life can be judged either from tool life or volume of material removal.
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2000 Mathematics Subject Classification: 60G52, 90B30.
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Elevated cholesterol in mid-life has been associated with increased risk of dementia in later life. We have previously shown that low density lipoprotein (LDL) is more oxidised in the plasma of dementia patients although total cholesterol levels remained unchanged [1]. We have investigated the hypothesis that amyloid beta production and neurodegeneration can be driven by oxidised lipids derived from LDL following the loss of blood brain barrier integrity with ageing. Therefore, we have investigated amyloid beta formation in SHSY5Y cells treated with LDL, minimally modified (ox) LDL, and lipids extracted from both forms of LDL. LDL-treated SHSY-5Y cell viability was not significantly decreased with up to 8 μg LDL/2 × 104 cells compared to untreated cells. However, 8 μg oxLDL protein/2 × 104 cells decreased the cell viability significantly by 33.7% (P < 0.05). A more significant decrease in cell viability was observed when treating cells with extracted lipids from 8 μg of LDL (by 32.7%; P < 0.01) and oxLDL (by 41%; P < 0.01). In parallel, the ratio of reduced to oxidised GSH was decreased; GSH concentrations were significantly decreased following treatment with 0.8 μg/ml oxLD-L (7.35 ± 0.58;P < 0.01), 1.6 μg/ml (5.27 ± 0.23; P < 0.001) and 4 μg/ml (5.31 ± 0.31; P < 0.001). This decrease in redox potential was associated with an increase acid sphingomyelinase activity and lipid raft formation which could be inhibited by desipramine; SHSY5Y cells treated with oxLDL, and lipids from LDL and oxLDL for 16 h showed significantly increased acid sphingomyelinase activity (5.32 ± 0.35; P < 0.05, 5.21 ± 0.6; P < 0.05, and 5.58 ± 0.44; P < 0.01, respectively) compared to control cells (2.96 ± 0.34). As amyloid beta production is driven by the activity of beta secretase and its association with lipid rafts, we investigated whether lipids from ox-LDL can influence amyloid beta by SHSY-5Y cells in the presence of oxLDL. Using ELISA and Western blot, we confirmed that secretion of amyloid beta oligomers is increased by SHSY-5Y cells in the presence of oxLDL lipids. These data suggest a mechanism whereby LDL, and more significantly oxLDL lipids, can drive amyloid beta production and cytotoxicity in neuronal cells. [1] Li L, Willets RS, Polidori MC, Stahl W, Nelles G, Sies H, Griffiths HR. Oxidative LDL modification is increased in vascular dementia and is inversely associated with cognitive performance. Free Radic Res. 2010 Mar; 44(3): 241–8.
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In this study, we developed a DEA-based performance measurement methodology that is consistent with performance assessment frameworks such as the Balanced Scorecard. The methodology developed in this paper takes into account the direct or inverse relationships that may exist among the dimensions of performance to construct appropriate production frontiers. The production frontiers we obtained are deemed appropriate as they consist solely of firms with desirable levels for all dimensions of performance. These levels should be at least equal to the critical values set by decision makers. The properties and advantages of our methodology against competing methodologies are presented through an application to a real-world case study from retail firms operating in the US. A comparative analysis between the new methodology and existing methodologies explains the failure of the existing approaches to define appropriate production frontiers when directly or inversely related dimensions of performance are present and to express the interrelationships between the dimensions of performance.
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The pyrolytic behaviour of individual component in biomass needs to be understood to gain insight into the mechanism of biomass pyrolysis. A comparative study on the pyrolysis of cellulose (hexose-based polysaccharides) and hemicallulose (pentose-based polysaccharides) is performed by two sets of experiments including TG analysis and Py-GC-MS/FTIR. The samples of these two polysaccharide components are thermally decomposed in TGA at the heating rate of 5 and 60 K/min to demonstrate the different characteristics of mass loss stage(s) between them. The yield of pyrolytic products is examined by a fluidized-bed fast pyrolysis unit. The experiment confirms that cellulose mainly contributes to bio-oil production (reaching the maximum of 72% at 580 °C), while hemicellulose works as an important precursor for the char production (∼25%). The compounds in the gaseous mixture (CO and CO2) and bio-oil (levoglucosan, furfural, aldehyde, acetone and acetic acid) are further characterized by GC-MS for cellulose and GC-FTIR for hemicellulose, and their formations are investigated thoroughly. © 2010 Elsevier Ltd. All rights reserved.
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The demand for fresh water production is growing day by day with the increase in world population and with industrial growth. Use of desalination technology is increasing to meet this demand. Among desalination technologies, solar stills require low maintenance and are readily affordable; however their productivity is limited. This paper aims to give a detailed review about the various types of solar stills, covering passive and active designs, single- and multi-effect types, and the various modifications for improved productivity including reflectors, heat storage, fins, collectors, condensers, and mechanisms for enhancing heat and mass transfer. Photovoltaic-thermal and greenhouse type solar stills are also covered. Material advances in the area of phase change materials and nanocomposites are very promising to enhance further performance; future research should be carried out in these and other areas for the greater uptake of solar still technology.
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The links between operational practices and performance are well studied in the literature, both theoretically and empirically. However, mostly internal factors are inspected more closely as the basis of operational performance, even if the impact of external, environmental factors is often emphasized. Our research fills a part of this existing gap in the literature. We examine how two environmental factors, market dynamism and competition impact the use of some operational practices (such as quality improvement, product development, automation, etc.) and the resulting operations and business performance. The method of path analysis is used. Data were acquired through an international survey (IMSS – International Manufacturing Strategy Survey), which was executed in 2005, in 23 participating countries in so called "innovative" industries (ISIC 28-35) with a sample of 711 firms. Results show that both market dynamism and competition have large impact on business performance, but the indirect effects, through operations practices are rather weak compared to direct ones. The most influential practices are from the area of process and control, and quality management.
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A lean termelési rendszer szociotechnikai megközelítése szerint a lean technikai elemei (technikai alrendszer) a kimagasló teljesítményt nyújtó munkaerő-szervezési rendszer (HPWS) gyakorlataival (szocio alrendszer) kapcsolódnak össze. A tanulmány ezt a megközelítést MacDuffie (1995) szervezetilogika-koncepciója alapján mutatja be. A lean termelési rendszer munkaerő-szervezési rendszerével kapcsolatosan négy témakört tekint át: (1) a lean termelési rendszer munkaerő-szervezési rendszerekre gyakorolt hatását, (2) a HPWSgyakorlatok használatát és (3) teljesítményhatását, végül a (4) munkásokra gyakorolt hatásokat. A feldolgozott koncepcionális és empirikus munkákban valamennyi pontban számos ellentmondás fedezhető fel. _____ According to the socio-technical view of lean production lean system is built on both technical and human resource practices (subsystems). The concept of organizational logic developed by MacDuffie (1995) describes how lean techniques and high performance working systems practices mutually suppose each other in lean environment. This study reviews four fields of human issues in relation to lean production: (1) the impact of lean system on work organization; (2) the use HPWS practices and (3) their impact on operational performance indicators in lean producers; (4) the impact of lean production on workers. The review of empirical and conceptual studies points out that there are many contradictions regarding the above points.
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Environmental protectionism and sustainable development has been gaining increased attention among governments, investors and consumers alike. As a result, firms are facing growing pressure from the various stakeholders to improve their environmental performance. This study is focusing on the food industry, which in recent years has been a subject of increased scrutiny due to their role in resource consumption, waste generation and unsustainable production practices. Our research is aiming to examine how the financial community evaluates the environmental stewardship of food industry companies as proxied by market reactions in response to environmental news. Are all company related environmental news items evaluated equally, and which financial and non-financial firm-specific attributes can influence market responses? Have there been changes in reactions on the stock exchange in the past two decades?
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The implementation of country-specific supply chain coordination techniques ensures an optimal global supply chain performance. This paper looks at success factors going with a supply chain coordination strategy within the global supply chain of a successful, medium-sized, privately-owned company, one having locations in North America (USA), Europe (Hungary) and Asia (China). Through the shown GSL’s Chinese plant, we will endeavor to argue that increased collaboration in the supply network with appropriate supply chain coordination brings down not only the inventory level but can also improve conformance quality and reduce quoted lead times.
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The so-called "High Performance Working System" (HPWS) and the lean production are representing the theoretical and methodological foundations of this paper. In this relation it is worth making distinction between various theoretical streams of the HPWS. The first theoretical stream in the literature is focusing on the diffusion of the Japanese-style management and organizational practices both in the US and in the Europe. The second theoretical strand comprises the approach of sociology of work and dealing with the learning/innovation capabilities of the new forms of work organization. Finally, the third theoretical approach is addressing on the types of knowledge and learning process and their relations with the innovation capabilities of the firm. The authors’ analysis is based on the international comparison, both in regional and in cross country comparison. For regional comparison the share of ICT clusters in Europe, USA and the rest of the world was assessed. For the purpose of the cross-country comparison in the EU, the innovation performance measured by the index Innovation Union Scoreboard (IUS) was used in both the before and after the financial crisis.
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This paper, using detailed time measurements of patients complemented by interviews with hospital management and staff, examines three facets of an emergency room's (ER) operational performance: (1) effectiveness of the triage system in rationing patient treatment; (2) factors influencing ER's operational performance in general and the trade-offs in flow times, inventory levels (that is the number of patients waiting in the system), and resource utilization; (3) the impacts of potential process and staffing changes to improve the ER's performance. Specifically, the paper discusses four proposals for streamlining the patient flow: establishing designated tracks (fast track, diagnostic track), creating a holding area for certain type of patients, introducing a protocol that would reduce the load on physicians by allowing a registered nurse to order testing and treatment for some patients, and potentially and in the longer term, moving from non-ER specialist physicians to ER specialists. The paper's findings are based on analyzing the paths and flow times of close to two thousand patients in the emergency room of the Medical Center of Leeuwarden (MCL), The Netherlands. Using exploratory data analysis the paper presents generalizable findings about the impacts of various factors on ER's lead-time performance and shows how the proposals fit with well-documented process improvement theories. © 2010 Elsevier B.V. All rights reserved.