2,119 research outputs found
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Knowledge based system implementation for lean process in low volume automotive manufacturing (LVAM) with reference to process manufacturing
YesGlobal manufacturing industry mostly depends on new product development and processes to
become competitive. The product development process for automotive industry is normally
complicated, lengthy, expensive, and risky. Hence, a study of lean manufacturing processes for
low volume manufacturing in automotive industry is proposed to overcome this issue by
eliminating all wastes in the lengthy process. This paper presents a conceptual design approach to
the development of a hybrid Knowledge Based (KB) system for lean process in Low Volume
Automotive Manufacturing (LVAM). The research concentrates on the low volume processes by
using a hybrid KB system, which is a blend of KB system and Gauging Absences of Pre-requisites
(GAP). The hybrid KB/GAP system identifies all potential waste elements of low volume process
manufacturing. The KB system analyses the difference between the existing and the benchmark
standards for lean process for an effective implementation through the GAP analysis technique.
The proposed model explores three major lean process components, namely Employee
Involvement, Waste Elimination, and Kaizen (continuous improvement). These three components
provide valuable information in order for decision makers to design and implement an optimised
low volume manufacturing process, but which can be applied in all process manufacturing,
including chemical processing
Decomposition of manufacturing processes: a review
YesManufacturing is a global activity that started during the industrial revolution in the late
19th century to cater for the large-scale production of products. Since then,
manufacturing has changed tremendously through the innovations of technology,
processes, materials, communication and transportation. The major challenge facing
manufacturing is to produce more products using less material, less energy and less
involvement of labour. To face these challenges, manufacturing companies must have a
strategy and competitive priority in order for them to compete in a dynamic market. A
review of the literature on the decomposition of manufacturing processes outlines three
main processes, namely: high volume, medium volume and low volume. The
decomposition shows that each sub process has its own characteristics and depends on
the nature of the firm’s business. Two extreme processes are continuous line production
(fast extreme) and project shop (slow extreme). Other processes are in between these
two extremes of the manufacturing spectrum. Process flow patterns become less
complex with cellular, line and continuous flow compared with jobbing and project. The
review also indicates that when the product is high variety and low volume, project or
functional production is applied.The financial support by the Malaysian Government, Universiti Malaysia Pahang and Bradford University for this research is gratefully acknowledged
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Performance measurement system for a manufacturing environment: KB/GAP/AHP approach
YesDesigning and implementing Performance Measurement System (PMS) is an integral part of management control systems. This paper presents an original and novel approach to designing and benchmarking of PMSs for a manufacturing environment through a hybrid framework which overcomes the shortcomings of earlier models. A detailed review was taken of previous models and their limitations were identified. The present hybrid PMS model seeks to improve the earlier research models by the following novel approach: implementation of a Knowledge Based (KB) expert system, Gauging Absences of Pre-requisite (GAP) analysis and Analytic Hierarchy Process (AHP) methodology in an integrated KBPMS. The paper has shown that the present hybrid (KB-AHP-GAP) approach to developing a KBPMS model is a realistic methodology. The combination of the KB-AHP-GAP approach allows detailed benchmarking of the PMS existing within a manufacturing organisation. Furthermore, this approach can assist in identifying and prioritising the key decisions that need to be actioned to overcome the existing PMS shortcomings
Novel heuristic for low-batch manufacturing process scheduling optimisation with reference to process engineering
YesScheduling is an important element that has a major impact on the efficiency of all
manufacturing processes. It plays an important role in optimising the manufacturing times and
costs resulting in energy efficient processes. It has been estimated that more than 75% of
manufacturing processes occur in small batches. In such environments, processes must be able to
perform a variety of operations on a mix of different batches. Batch-job scheduling optimisation is
the response to such low batch manufacturing problems. The optimisation of batch-job process
scheduling problem is still a challenge to researchers and is far from being completely solved due
to its combinatorial nature. In this paper, a novel hybrid heuristic (HybH) solution approach for
batch-job scheduling problem is presented with the objective of optimising the overall Makespan
(Cmax). The proposed HybH is the combination of Index Based Heuristic (IBH) and the Finished
Batch-Job (FBJ) process schedule. The heuristic assigns the first operation to a batch-job using
IBH and the remaining operations on the basis FBJ process schedule. The FBJ process schedule
gives priority to the batch-job with early finished operations, without violating the constraints of
process order. The proposed HybH is explained with the help of a detailed example. Several
benchmark problems are solved from the literature to check the validity and effectiveness of the
proposed heuristic. The presented HybH has achieved batch-job process schedules which have
outperformed the traditional heuristics. The results are encouraging and show that the proposed
heuristic is a valid methodology for batch process scheduling optimisation
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Simulation Model of Maritime Inventory Routing Problem with Particular Application to Cement Distribution
yesSimulation is undoubtedly a very useful tool for modelling a system specifically in the presence of stochastic elements and complex interactions between the system entities. In this paper, a simulation model to support decision making in ship scheduling for Maritime Inventory Routing Problem (MIRP) with particular application to cement distribution is presented. The system under study is a combined discrete and continuous system, where a heterogeneous fleet of ships with various sizes and types of contracts transport bulk cement products from production facility (Central Supply, CS) of a cement company to its packing plants (Distribution Centres, DCs). The simulation model in this study has been designed and developed thoroughly to emulate the complexity of the real system of the MIRP. The simulation model has demonstrated the capability to provide support for decision making in ship scheduling of the heterogeneous shipping fleet in the following forms: (a) real time states of inventory levels at CS and DCs and (b) ships’ routing. In addition, one of the main strength of this simulation model is its flexibility. It can be easily expanded or adjusted to different size of system entities for example number of CSs, DCs, berths, vessels, and products.Support for this research is provided by the Directorate of Higher Education, Ministry of National Education, Republic of Indonesi
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Development of an Interface Analysis Template for System Design Analysis
yesInterface definition is an essential and integral part of systems engineering. In current practice, interface requirements or control documents are generally used to define systems or subsystems interfaces. One of the challenges with the use of such documents in product development process is the diversity in their types, methodology, contents coverage, and structure across various design levels and across multidisciplinary teams, which often impedes the design process. It is important that interface information is described with appropriate detail and minimal or no ambiguity at each design level. The purpose of this paper is to present an interface analysis template (IAT) as a structured tool and coherent methodology, built upon a critical review of existing literature concepts, with the aim of using and implementing the same template for capturing interface requirements at various levels of design starting from stakeholders' level down to component level analysis. The proposed IAT is illustrated through a desktop case study of an electric pencil sharpener, and two examples of application to automotive systems
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Application of the interface analysis template for delivering system requirements
yesThis paper presents a structured approach for systems requirements analysis that integrates use case modelling with a coherent flows based approach for describing interface exchanges based on the Interface Analysis Template. The approach is discussed in the context of current frameworks for requirements elicitation from the engineering design and systems engineering domains, and it is illustrated with an automotive case study. This illustrates the strength of the framework to support structured multi-domain and multi-disciplinary analysis of requirements for complex systems
Role of serum angiotensin converting enzyme in sarcoidosis
This study was conducted to determine the role of Serum Angiotensin Converting Enzyme (SACE) as a marker in the differential diagnosis of pulmonary diseases and prognosis of sarcoidosis, A retrospective analysis of 113 medical records of patients at The Aga Khan University Hospital, with laboratory investigation for SACE was performed. Among 113 patients, 51 cases were found to have sarcoidosis, 44 of them had SACE levels greater than 52 lU/L (mean ACE 104.44). SACE levels were also found elevated in other clinical conditions like tuberculosis (mean 58.64 lUlL), but the enzyme level were less (p0.04) than those found in sarcoidosis (mean (92-97 lUlL). SACE activity was found to be considerably lower in other chronic lung diseases such as, fibrosing alveolitis (mean 43.98 lUlL), interstitial lung disease (mean 42.11 lU/L) and chronic obstructive lung disease (mean 40.85 lUlL). Twenty patients of sarcoidosis, who received steroid tretalment subsequently showed a decline in the SACE levels. SACE is a useful marker in differential diagnosis as 37.2% cases of sarcoidosis compared to only 9.09% of tuberculosis had SACE levels greater than 100 lUlL. In addition, our data also suggest that serum ACE is useful for the diagnosis as well as monitoring prognosis in sarcoidosis (JPMA 48:131,1998)
Pulmonary infiltrates during chemotherapy-induced febrile neutropenia: incidence, patterns and outcomes
OBJECTIVE: To analyze the incidence, etiologies, radiographic patterns, and clinical outcomes of adult leukemics with prolonged febrile neutropenia and pneumonia. METHODS: A retrospective study was conducted at a tertiary care hospital. The medical records of adult patients with acute myeloid leukemia diagnosed between January 1989 and June 2000 and undergoing induction chemotherapy were included. Only the patients who presented with a pulmonary infiltrate, secondary leukemia (e.g., transformed chronic myeloid leukemia underlying myelodysplastic syndrome, or disease following alkylating agent therapy) were included and those developing infiltrates following consolidation chemotherapy were excluded. RESULTS: A total of 124 patients were admitted to the hospital with a diagnosis of AML during the study period. Thirty-one patients were excluded; 93 patients received induction chemotherapy and were included in the study analysis. The median age was 36 years (15 - 70 years); 58 males and 35 females. Sixty two percent patients received Cytosine Arabinoside (Ara-C), 17% received Etoposide, 11% received Ara-C and Mitoxantrone, and 6% received All-trans-retinoic Acid. The mean onset and duration of neutropenia were 5 and 15 days, respectively. Pulmonary infiltrates were identified during 45% of neutropenic episodes. A presumptive causative organism was isolated from 50% of patients with an infiltrate: Gram-positive bacteria were most common (47%) followed by Gram-negative bacilli (33%) and fungi (20%). Survival data were available for 88 patients; median disease free survival for the entire cohort was 7 months. Male sex (p=0.015), onset of neutropenia (p=0.02) and bilateral distribution of an infiltrate (p=0.03) were statistically significant predictors of early mortality. For patients with and without pneumonia, the median disease-free interval and overall survival were 2.5 and 4.6 months and 9 and 13 months (p=0.038 and p=0.095) respectively. CONCLUSION: Neutropenia occurred at a mean of 5.0 after initiation of induction chemotherapy. The majority of patients had bilateral pulmonary infiltrates. Male sex, onset of neutropenia and bilateral distribution of an infiltrate were found to be statistically significant predictors of early mortality
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A Framework for Complex Product Architecture Analysis using an Integrated Approach
YesContemporary design decomposition and synthesis analytical tasks at the conceptual design stage reply on functional and structural modelling approaches. There is a wide diversity of elements used by various modelling approaches for information and representation of product architecture, which incurs difficulties for multidisciplinary engineers working across different phases of design in capturing, visualising, sharing and tracing consistent yet common knowledge and elements across the function and structure domains. This prompts for fixation of detail and common modelling knowledge across both functional and structural analytical approaches which is also critical from automatized software perspective. A limitation of existing approaches is that they tend to focus more on ‘what’ and less on ‘how’ (and vice versa). This paper proposes an integrated conceptual product architecting approach that combines and expands the functional and structural modelling approaches, enabling capturing and tracing knowledge coherently through a common binding domain. This is underpinned by the view that most interaction requirements amongst the physical components during structural modelling can be derived from functional modelling. The proposed integrated approach is underpinned by the critical analysis and synthesis of existing approaches in literature dealing with functional and structural architecture analysis, integrated within a Multiple Domain Matrix (MDM) to fuse the knowledge of both solution independent (functional) and dependent (structural) analyses. The proposed framework is illustrated with a case study of solar robot toy, followed by discussion and suggestions for future work
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