Analysis Of Production Lines Research Articles

Analysis of Production Line with Finite Buffers and a General Service Term

This paper considers a production line with continuous loading at the first automation service station or machine and buffers placed forward the queuers. Each machine operates within an indefinite service time. There is much data available on modeling and analysis of the transfer lines. However, most of the results are for the steady-state operation. The system under consideration operates within the finite time interval. A method is suggested to study the production line. According to the method, we chart the system operation process; calculate of distribution formula for the remaining durations of time period of the system being in the states marked at the chart. Then we calculate the state indexes. A detailed description of the states allows calculating, for example, blocking machine indexes and machine down time probabilities and durations.

Production Line Analysis via Value Stream Mapping: A Lean Manufacturing Process of Color Industry

Lean Manufacturing (LM) is a business strategy that was developed in Japan. The main role of lean manufacturing is to determine as well as to eliminate the waste. Companies implement LM to keep their competitiveness over their competitors by improving the manufacturing system's productivity and quality enhancement of the product. The goal of this paper is to apply one of the most significant lean manufacturing techniques called Value Stream Mapping (VSM) to improve the production line of a color industry as a case of study. To achieve this goal, lean fundamental principles was implemented to construct VSM for identification and elimination of wastes by using team formation, product selection, conceptual design, and time-frame formulation through takt time calculation. Based on the future VSM, final results showed that by implementing some lean thinking techniques, Production Lead-time (PLT) decreased from 8.5 days to 6 days, and the value added time decreased from 68 minutes to 37 minutes.

The throughput rate of serial production lines with deterministic process times and random setups

We conduct exact analysis of serial production lines with deterministic service durations and various classes of random state-dependent setups between customers. Our focus is on assessing the produ...

Improving the management of product lines by performing domain knowledge extraction and cross product line analysis

ContextIncrease in market competition is one of the main reasons for developing and maintaining families of systems, termed Product Lines (PLs). Managing those PLs is challenging, let alone the management of several related PLs. Currently, those PLs are managed separately or their relations are analyzed assuming explicit specification of dependencies or use of an underlying terminology. Such assumptions may not hold when developing the PLs in different departments or companies applying various engineering processes. ObjectiveIn this work we call for utilizing the knowledge gained from developing and maintaining different PLs in the same domain in order to recommend on improvements to the management of PLs. MethodThe suggested approach conducts domain knowledge extraction and cross PL analysis on feature diagrams – the main aid for modeling PL variability. The domain knowledge is extracted by applying similarity metrics, clustering, and mining techniques. Based on the created domain models, the approach performs cross PL analysis that examines relations in the domain models and generates improvement recommendations to existing PLs and overall management recommendations (e.g., merging or splitting PLs). ResultsThe approach outcomes were evaluated by humans in a domain of mobile phones. The evaluation results may provide evidence that the outcomes of the approach in general and its recommendations in particular meet human perception of the given domain. ConclusionWe conclude that through domain knowledge extraction and cross PL analysis the suggested approach may generate recommendations useful to the management of individual PLs, as well as to the overall management of different PLs in the same domain.

Reliability Defects Identification of Serial Production Systems: Application to a Piston Production Line

Failure and repair data are urgently needed for reliability and maintainability analysis of production lines. A piston production line is traced, and field failure data during a period of 15 months are collected. The statistical analysis of the failure and repair data and the determination of the theoretical distributions parameters that best fit to failure data were carried out, based on which, reliability of the piston production line is evaluated from a global perspective. Furthermore, a failure losses-based importance measure method for repairable systems was proposed and used for reliability defects identification of the piston production line from a local perspective, the primary failure modes and equipments that were prone to failures were ranked with this method. This analysis will be essential and valuable to identify the reliability problems for current and further designing projects of production lines for piston or other important parts of motor engine.

Performance Analysis of Exponential Multi-Server Production Lines with Fluid Flow and Finite Buffers

This article presents an approximation method for fluid flow production lines with multi-server workstations and finite buffers. Each workstation consists of parallel identical servers, which are subject to operation-dependent failures with exponentially distributed uptimes and downtimes. The proposed method decomposes the production line into single-buffer subsystems, each described by a continuous state Markov process, the parameters of which are determined iteratively. The approximation method is appropriate for the analysis of longer production lines, able to accurately estimate performance characteristics (e.g., throughput and mean buffer content), and shown to perform well on a large test set.

A Classification and Survey of Analysis Strategies for Software Product Lines

Software-product-line engineering has gained considerable momentum in recent years, both in industry and in academia. A software product line is a family of software products that share a common set of features. Software product lines challenge traditional analysis techniques, such as type checking, model checking, and theorem proving, in their quest of ensuring correctness and reliability of software. Simply creating and analyzing all products of a product line is usually not feasible, due to the potentially exponential number of valid feature combinations. Recently, researchers began to develop analysis techniques that take the distinguishing properties of software product lines into account, for example, by checking feature-related code in isolation or by exploiting variability information during analysis. The emerging field of product-line analyses is both broad and diverse, so it is difficult for researchers and practitioners to understand their similarities and differences. We propose a classification of product-line analyses to enable systematic research and application. Based on our insights with classifying and comparing a corpus of 123 research articles, we develop a research agenda to guide future research on product-line analyses.

The throughput rate of serial production lines with deterministic process times and random setups: Markovian models and applications to semiconductor manufacturing

We conduct exact analysis of serial production lines with deterministic service durations and various classes of random state-dependent setups between customers. Our focus is on assessing the production rate, or just-in-time (JIT) throughput. We demonstrate that such systems can be modeled as a Markov chain and consider various types of setups inspired by clustered photolithography tools in semiconductor manufacturing. We deduce when exact closed form expressions for the production rate are possible and when a numeric solution to the Markov chain balance equations are required. As these systems have shown promise for modeling process bound clustered photolithography tools, we study their accuracy versus detailed simulation for predicting the tool throughput. Various practical features such as the capacity of a pre-scan buffer and batch customers (to model wafer lots) are investigated.

Safety analysis of mechatronic product lines

Most methodologies for the design and analysis of mechatronic systems target a single product. From a business perspective, successful product development requires shortening development times, reducing engineering costs and offering a greater variety of product options for customers. In software engineering, the software product line (SPL) technology has been developed to meet these conflicting goals, and several major companies have reported success stories resulting from SPL adoption. In mechanical engineering, similar methodologies have been developed under the name of product platforms. Methodologies for analyzing product qualities such as safety or reliability have been introduced for both SPL and product platforms. The problem with these methodologies is that they consider either software or mechanical product design, so they do not guide developers to find the best balance between the controller and the equipment to be controlled. Several system properties of a mechatronic product line should be investigated with mechatronic analysis methodologies before the development process branches to software, electronic and mechanical design. In particular, safety is one system property that can only be analyzed by considering both the equipment and its controller, so mechatronic methodologies early in the design are advantageous for discovering safety-related design constraints before costly design commitments are made. This paper extends the Functional Failure Identification and Propagation (FFIP) framework to the safety analysis of a mechatronic product line with options in software signal connections and equipment. The result of applying FFIP is that unsafe combinations of options are removed from the product line.

Performance Analysis of Non-Homogeneous Hybrid Production Lines

 Abstract—For analyzing performance of non-homogeneous hybrid lines, a new technique of dealing with nonhomogeneous lines is proposed to transform a non-homogeneous production line into a homogeneous line, which is based on decomposition method. The technique extends the applicability of decomposition method to nonhomogeneous lines. The technique is discussed by numerical experiments comparing with aggregation method, what's more, the advantages and disadvantages are specified. The technique complements and develops the system analysis techniques of hybrid production lines. Index Terms—Hybrid system, system performance, Non-homogeneousness, decomposition method.

SIMULATION MODELING OF AUTOMATIC PRODUCTION LINES WITH INTERMEDIATE BUFFERS

A production line is an important class of manufacturing system when large quantities of identical or similar products are to be produced. The performance of a production line is highly influenced by machine failures. When a machine fails, it is then be unavailable during a certain amount of time required to repair it. Analysis of production lines divides into three types: analytical, approximation and simulation models. The analytical and approximation models have assumptions, which make these models unrealistic such as reliable workstations, certain processing distribution, the first workstation cannot be starved and the last workstation cannot be blocked. The main problems in production lines treatment are the calculation of throughput and average levels of buffers because of the great size of state space. An analytical model is reviewed to clarify the limitations to use such treatment in real production lines. Simulation modeling of production lines is considered very important for designers interested in: Workload Allocation Problem (WAP), Server Allocation Problem (SAP), and Buffer Allocation Problem (BAP). This paper studies and analyzes the performance keys, which effect on production lines. A simulation model is developed by using ARENA software and used to analyze and test several bottlenecks that are causing severe congestions in different areas on the production line and could resolve all of these bottlenecks. In this paper, an actual cement production line is used as a case study. After a simulation time of 13 days, a simulation results show the line bottlenecks, workstations utilization, buffer capacities and the line production rate. The outputs clarify redesign of allocation of buffers, which verify an optimum size could be made; it might be taken into consideration when designers implement such lines. Finally modified better workstations utilization, buffer capacities and the line production rate with an increase about 15% of the production rate and economizing of 37 % from buffer capacities.

A comparison of product-based, feature-based, and family-based type checking

Analyzing software product lines is difficult, due to their inherent variability. In the past, several strategies for product-line analysis have been proposed, in particular, product-based , feature-based , and family-based strategies. Despite recent attempts to conceptually and empirically compare different strategies, there is no work that empirically compares all of the three strategies in a controlled setting. We close this gap by extending a compiler for feature-oriented programming with support for product-based, feature-based, and family-based type checking. We present and discuss the results of a comparative performance evaluation that we conducted on a set of 12 feature-oriented, Java -based product lines. Most notably, we found that the family-based strategy is superior for all subject product lines: it is substantially faster, it detects all kinds of errors, and provides the most detailed information about them.

Modeling and analysis of closed loop manufacturing systems using parameter coupling

Closed loop manufacturing systems (CLMSs) with recirculating material handling devices are extensively used in various industrial environments. The performance of such systems is impacted by many factors such as the total capacity of pallets, the actual number of pallets in the system, the machine reliability and processing time, the pallet index speed, and the positions of loading/unloading points. These factors make the accurate analysis and optimization of complex CLMSs very difficult and challenging. This paper presents a new parameter coupling technique to model and analyze a wide range of CLMSs. It is an enhancement based on the existing open production line analysis with unreliable assembly machines and finite buffers. Virtual assembly machines are introduced to represent the specific phenomena of CLMSs such as the recirculation of empty pallets and the sharing of conveyor space. Two types of parameter coupling patterns, the machine parameter coupling, and the buffer capacity coupling, are introduced to reflect the characteristics of the CLMSs. The parameter coupling technique is simple and effective for analyzing a broad range of CLMSs. Comparisons between this analytic method and simulation experiments demonstrate that the proposed parameter coupling technique is fast, accurate and robust.

Analysis of exponential reliable production lines using Kronecker descriptors

This paper presents a solution procedure for reliable production lines with service times distributed according to an exponential distribution, based on a Markovian formulation with a Kronecker structured representation (sum of tensor products). Specifically, structured Markovian formalisms are used to reduce the impact of the well-known state explosion problem associated with other methods of solution. Such formalisms combined with the Kronecker representation deliver memory efficiency in storing very large models, i.e. models with more than states. The exact steady-state solutions of these models may be obtained using efficient existing software packages. The proposed solution procedure is illustrated with two detailed examples, and generalised with a model construction algorithm. The computed throughput for several examples of production lines with perfectly reliable machines, as well as the computational costs in terms of CPU time to solve them with PEPS2007 and GTAexpress software packages, are also presented. In effect the paper demonstrates the power of the use of the Kronecker descriptor analysis applied to the derivation of the exact solution of the particular class of production lines considered. The Kronecker descriptor methodology is well-known to analysts concerned with computer and communication systems.

A formal framework for software product lines

ContextA Software Product Line is a set of software systems that are built from a common set of features. These systems are developed in a prescribed way and they can be adapted to fit the needs of customers. Feature models specify the properties of the systems that are meaningful to customers. A semantics that models the feature level has the potential to support the automatic analysis of entire software product lines. ObjectiveThe objective of this paper is to define a formal framework for Software Product Lines. This framework needs to be general enough to provide a formal semantics for existing frameworks like FODA (Feature Oriented Domain Analysis), but also to be easily adaptable to new problems. MethodWe define an algebraic language, called SPLA, to describe Software Product Lines. We provide the semantics for the algebra in three different ways. The approach followed to give the semantics is inspired by the semantics of process algebras. First we define an operational semantics, next a denotational semantics, and finally an axiomatic semantics. We also have defined a representation of the algebra into propositional logic. ResultsWe prove that the three semantics are equivalent. We also show how FODA diagrams can be automatically translated into SPLA. Furthermore, we have developed our tool, called AT, that implements the formal framework presented in this paper. This tool uses a SAT-solver to check the satisfiability of an SPL. ConclusionThis paper defines a general formal framework for software product lines. We have defined three different semantics that are equivalent; this means that depending on the context we can choose the most convenient approach: operational, denotational or axiomatic. The framework is flexible enough because it is closely related to process algebras. Process algebras are a well-known paradigm for which many extensions have been defined.

Approximate Performance Analysis of Production Lines with Continuous Material Flows and Finite Buffers

In this paper, we analyze production lines consisting of a number of machines in series with a finite buffer between each pair of machines. The flow of products through the machines is continuous. Each machine suffers from breakdowns, because of, for example, failures, cleaning and changeover. The up- and downtimes are independent and generally distributed. We develop a novel method to efficiently and accurately estimate the throughput and the mean buffer content of the production line. This method relies on decomposition of the production line into two-stage, one-buffer subsystems aggregating the up- and downstream part of the line. It is the use of aggregation of machine speeds, starvation times and blocking times, in combination with numerically stable matrix-analytic techniques for the steady-state subsystem analysis, that renders an efficient iterative method, capable of evaluating long production lines. We demonstrate that the proposed method performs well on a large test set consisting of over 49,000 cases, including production lines of up to 16 machines. Remarkably, the performance of the method does not deteriorate in case of highly unpredictable up- and downtimes, as often seen in practice. We apply the method to a bottling line at brewery Heineken Den Bosch and an assembly line at NXP Semiconductors.

Performance Analysis of Serial Production Lines with Deteriorating Product Quality

In manufacturing systems with perishable products (e.g., food, metal processing, etc.), the quality of a part is highly dependent on its residence time within the system. However, behavior and properties of these systems have not been studied systematically, and, therefore, is carried out in this paper. Specifically, we assume that the probability that each unfinished part is of good quality is a decreasing function of its residence time in the preceding buffer. Then, in the framework of serial production lines with machines having Bernoulli reliability model, we derive closed-form formulas for performance evaluation in the two-machine line case, and develop an aggregation-based procedure to approximate the performance measures in M > 2-machine lines. In addition, we study monotonicity properties of these production lines using numerical experiments. Finally, a case study in an automotive stamping plant is discussed.

Performance analysis of exponential production lines with fluid flow and finite buffers

This article presents an approximative analysis of production lines with fluid flow, consisting of a number of machines or servers in series and a finite buffer between each pair of servers. Each server suffers from operationally dependent breakdowns, characterized by exponentially distributed up- and downtimes. An iterative method is constructed that efficiently and accurately estimates performance characteristics such as throughput and mean total buffer content. The method is based on decomposition of the production line into single-buffer subsystems. Novel features of the method are (i) modeling of the aggregate servers in each subsystem; (ii) equations to iteratively determine the processing behavior of these servers; and (iii) use of matrix-analytic techniques to analyze each subsystem. The proposed method performs well on a large test set, including long and imbalanced production lines. For production lines with imbalance in mean downtimes, it is shown that a more refined modeling of the servers in each subsystem leads to significantly better performance.

AoURN-based modeling and analysis of software product lines

Software Product Line Engineering concerns itself with domain engineering and application engineering. During domain engineering, the whole product family is modeled with a preferred flavor of feature models and additional models as required (e.g., domain models or scenario-based models). During application engineering, the focus shifts toward a single family member and the configuration of the member's features. Recently, aspectual concepts have been employed to better encapsulate individual features of a Software Product Line (SPL), but the existing body of SPL work does not include a unified reasoning framework that integrates aspect-oriented feature description artifacts with the capability to reason about stakeholders' goals while taking feature interactions into consideration. Goal-oriented SPL approaches have been proposed, but do not provide analysis capabilities that help modelers meet the needs of the numerous stakeholders involved in an SPL while at the same time considering feature interactions. We present an aspect-oriented SPL approach for the requirements phase that allows modelers (a) to capture features, goals, and scenarios in a unified framework and (b) to reason about stakeholders' needs and perform trade-off analyses while considering undesirable interactions that are not obvious from the feature model. The approach is based on the Aspect-oriented User Requirements Notation (AoURN) and helps identify, prioritize, and choose products based on analysis results provided by AoURN editor and analysis tools. We apply the AoURN-based SPL framework to the Via Verde SPL to demonstrate the feasibility of this approach through the selection of a Via Verde product configuration that satisfies stakeholders' needs and results in a high-level, scenario-based specification that is free from undesirable feature interactions.

Clothing Workshop Production Line Analysis and Improvement Research Based on IE

In the face of problems of labor shortage, high cost and low efficiency, if the company can implement industrial projects scientifically, enterprises could effectively increase the garment processing efficiency and enhance their marketability. This article firstly takes a clothing firm for example, analyzes and identifies problems on the production line, by using methods of program analyzing and stopwatch measuring; Secondly, this article will analyze enterprises’ methods of working and balancing to improve its balance; Finally, the results show that the application of the researching method has dramatically increased the balance of the assembly line and enterprises’ production rate.