Performance management in flexible manufacturing systems

This article treats several performance management decision problems in flexible manufacturing systems (FMSs). This work differs from a number of other studies in that we allow the processing rates at the machines to be varied, and the system has to meet a given throughput goal per unit time. The managerial decision options modeled here include part routing and allocation of tasks to machines, work-in-progress (WIP) levels, capacity expansions, tool-type selection, the setting of throughput goals, and multiperiod production planning. We discuss and explain the insights and implications, partly nonintuitive, gained from our investigations. Finally, extensive numerical evaluations are included to illustrate the economic and performance impact of the various performance management alternatives. These results demonstrate that substantial economic benefits can be achieved by careful tuning of the FMS operational parameters.     

Cutting-tool management in computer-integrated manufacturing

The problem of cutting tool management has been brought to the forefront with the emergence of computer-integrated manufacturing (CIM) and, in particular, flexible manufacturing systems (FMSs). The financial and operational ramifications of effective tool management has spurred considerable research in this area during the past decade and many researchers are proposing sound solutions to various facets of this broad-ranging and difficult problem. This paper identifies critical areas of research for the development of tool management systems in CIM. To develop a framework for this, the paper examines and categorizes work in academia and in industry on the management of cutting-tools in CIM and describes some key implementations, particularly in the metal-cutting industry. The solution of manufacturing problems generally demands an eclectic approach, and for this reason, we have tried to taxonomize, describe, and critique the various research thrusts in an attempt to provide a synthesis of use in more unified approaches.     

Implementation of a configurable laboratory information management system for use in cellular process development and manufacturing

Background aimsRegulatory requirements for the manufacturing of cell products for clinical investigation require a significant level of record-keeping, starting early in process development and continuing through to the execution and requisite follow-up of patients on clinical trials. Central to record-keeping is the management of documentation related to patients, raw materials, processes, assays and facilities.MethodsTo support these requirements, we evaluated several laboratory information management systems (LIMS), including their cost, flexibility, regulatory compliance, ongoing programming requirements and ability to integrate with laboratory equipment. After selecting a system, we performed a pilot study to develop a user-configurable LIMS for our laboratory in support of our pre-clinical and clinical cell-production activities. We report here on the design and utilization of this system to manage accrual with a healthy blood-donor protocol, as well as manufacturing operations for the production of a master cell bank and several patient-specific stem cell products.ResultsThe system was used successfully to manage blood donor eligibility, recruiting, appointments, billing and serology, and to provide annual accrual reports. Quality management reporting features of the system were used to capture, report and investigate process and equipment deviations that occurred during the production of a master cell bank and patient products.ConclusionsOverall the system has served to support the compliance requirements of process development and phase I/II clinical trial activities for our laboratory and can be easily modified to meet the needs of similar laboratories.     

A model management systems approach to manufacturing systems design

Manufacturing systems design involves the solution of a complex series of interrelated problems. This complexity will increase in the future as manufacturing practices change to meet increased global competition. Research within manufacturing systems design has mainly been focused on finding improved models for solving particular problems, or extending existing modeling techniques. This has resulted in numerous modeling tools being available to support manufacturing systems design. However, little research work has been carried out into consolidating the existing theories and models. As a result, a large body of this work has not been applied in industry. Model management has evolved as a research area which investigates methods for storing, modifying, and manipulating models. This article describes a prototype model management system for manufacturing systems design. The objective here is not to develop “another” decision support system for manufacturing design, but to illustrate, through the development of a prototype system, a number of key ideas of how concepts from the area of model management systems can be used to support manufacturing systems design. The prototype model management system utilizes the structured modeling framework and uses an extended version of the structured modeling language. An important aspect of the prototype model management system is the incorporation of the model development task, thus allowing the system to be easily updated and adapted. The prototype system was evaluated using a range of queueing network models for manufacturing systems design.     

Performance evaluation of a machine vision system for insect pests identification of field crops using artificial neural networks

Feature extraction is a crucial part of advanced image recognition systems. In this research, an autonomous detection device was designed and developed for insect pest detection to improve the ability of intelligent systems in order to annihilate harmful insect pests in agricultural crop fields. Device included a dark chamber, a CCD digital camera, a LDR lightening module and a personal computer. The proposed programme for precise insect pest detection was based on an image processing algorithm and artificial neural networks (ANNs). After image acquisition, the insect pests’ images were extracted from original images with Canny filtration. Afterwards, four morphological and three textural features from the obtained images were measured and normalised. Performance of ANN model was tested successfully for Beet armyworm (Spodoptera exigua) recognition in images using back-propagation supervised learning method and inspection data. Results showed that proposed system was able to identify S. exigua in the images from other species. Such this machine vision system can be used in autonomous field robots to achieve a modern farmer’s assistant.     

Complexity management in visualizing protein interaction networks

MOTIVATION: Protein-protein interaction networks often consist of thousands of nodes or more. This severely limits the utility of many graph drawing tools because they become too slow for an interactive analysis of the networks and because they produce cluttered drawings with many edge crossings. RESULTS: A new layout algorithm with complexity management operations in visualizing a large-scale protein interaction network was developed and implemented in a program called InterViewer3. InterViewer3 simplifies a complex network by collapsing a group of nodes with the same interacting partners into a composite node and by replacing a clique with a star-shaped subgraph. The experimental results demonstrated that InterViewer3 is one order of magnitude faster than the other drawing programs and that its complexity management is successful.     

药品生产质量保证体系的建立

以《药品生产质量管理规范》(GMP)为依据,运用“过程方法”、“管理的系统方法”和“层次分析”理论,以药品生产体系的增值链系统为线索,对药品生产质量管理中的工序控制、信息传递、各子系统间的关联和衔接进行分析,以流程图的形式表示,并将系统要素人、物、信息和程序控制标明,建立起质量保证体系。涵盖了系统的全部关键质量控制点,职责清晰、不易遗漏、便于控制和发现问题。解决了药品生产质量控制及GMP实施中的难点,是药品生产企业行之有效的质量管理的手段。     

Allocating buffer storages in a flexible manufacturing system

This article reports an approximation scheme to determine buffer capacities required to achieve the target performance level in a general flexible manufacturing system with multiple products. This work extends our previous study of sequential production lines with a single product. The manufacturing system is operated using a pull mechanism, and the performance level is measured by the average proportion of demands backlogged. Simulation experiments were performed to study the validity of the approximation scheme under various situations.     

Scheduling algorithms for a two-machine flexible manufacturing system

The flexible manufacturing system (FMS) considered in this paper is composed of two CNC machines working in series—a punching machine and a bending machine connected through rollers acting as a buffer system of finite capacity. The main difference between the present problem and the standard two-machine flow shop problem with finite intermediate capacity is precisely the buffer system, which in our problem consists of two stacks of parts supported by rollers: the first stack contains the output of the punching machine, while the second stack contains the input for the bending machine. When the second stack is empty, the first stack may be moved over. Furthermore, the capacity of each stack depends on the particular part type being processed. The FMS can manufacture a wide range of parts of different types. Processing times on the two machines are usually different so that an unbalance results in their total workload. Furthermore, whenever there is a change of the part type in production, the machines must be properly reset—that is, some tools need to be changed or repositioned. A second important difference between the present problem and the usual two-machine flow shop problem is the objective. Given a list ofp part types to be produced in known quantities, the problem considered here is how to sequence or alternate the production of the required part types so as to achieve various hierarchical targets: minimize the makespan (the total time needed to complete production) and, for instance, compress the idle periods of the machine with less workload into a few long enough intervals that could be utilized for maintenance or other reasons. Although Johnson's rule is optimal in some particular cases, the problem addressed in the paper isNP-hard in general: heuristic procedures are therefore provided.     

Performance analysis of virtual clusters in personal communication networks

The objective of the paper is to analyze the performance of virtual cluster architectures in wireless networks. The key issues in wireless domain are flooding, connectivity, and power management. These issues arise during the path finding and maintenance between source and destination nodes. To overcome these issues three approaches are introduced in this paper namely; fusion virtual structure, link quality connected dominating set and cluster backbone approach. These approaches follow the distributed localized computations for virtual cluster constructions and focus on fundamental connectivity problems and are partially involved in power saving process of individual nodes. The proposed methods are analyzed in terms of backbone size, packet delivery ratio and normalized routing overhead and the results are witnessed by simulation.     

Scheduling tasks and vehicles in a flexible manufacturing system

Due to their increasing applicability in modern industry, flexible manufacturing systems (FMSs), their design, and their control have been studied extensively in the recent literature. One of the most important issues that has arisen in this context is the FMS scheduling problem. This article is concerned with a new model of an FMS system, motivated by the practical application that takes into account both machine and vehicle scheduling. For the case of a given machine schedule, a simple polynomial-time algorithm is presented that checks the feasibility of a vehicle schedule and constructs it whenever one exists. Then a dynamic programming approach to construct optimal machine and vehicle schedules is proposed. This technique results in a pseudopolynomialtime algorithm for a fixed number of machines.     

Signaling networks in the plant circadian system

Significant advances have been made during the past year in the genetic and molecular dissection of the plant circadian system. Several proteins involved in circadian clock regulation have been identified and the way that their interactions contribute to temporal organization is starting to emerge. In addition, genomic approaches have identified hundreds of genes under clock control, providing a molecular basis to our understanding of how the clock coordinates plant physiology and development with daily and seasonal environmental cycles.     

Content-based image retrieval system using neural networks

An effective image retrieval system is developed based on the use of neural networks (NNs). It takes advantages of association ability of multilayer NNs as matching engines which calculate similarities between a user's drawn sketch and the stored images. The NNs memorize pixel information of every size-reduced image (thumbnail) in the learning phase. In the retrieval phase, pixel information of a user's drawn rough sketch is inputted to the learned NNs and they estimate the candidates. Thus the system can retrieve candidates quickly and correctly by utilizing the parallelism and association ability of NNs. In addition, the system has learning capability: it can automatically extract features of a user's drawn sketch during the retrieval phase and can store them as additional information to improve the performance. The software for querying, including efficient graphical user interfaces, has been implemented and tested. The effectiveness of the proposed system has been investigated through various experimental tests.     

Developing a computer control system for a flexible manufacturing cell

This article focuses on the development of a computer control system for a flexible manufacturing cell. The paper outlines the various modules that are required for a computer control system and elaborates on the development of some of these modules. This is part of an ongoing research project at the University of the Witwatersrand. The aim of the project is to demonstrate the viability of flexible manufacturing systems to South African industry. Thus the main constraints of the project were cost, ease of implementation, and ease of maintainability. This necessitated the use of existing machinery and of computer systems and software that were readily available and already familiar to industry.     

Organizing life cycle management in practice: challenges of a multinational manufacturing corporation

Purpose

The environmental life cycle management (LCM) literature proposes many factors considered critical in order to successfully conduct LCM. This study contrasts these vague and general factors proposed as critical to LCM in existing literature, with detailed accounts of LCM in practice.

Methods

A literature review of three related research fields, i.e., LCM, life cycle thinking, and sustainable supply chain management, is contrasted with a study of how LCM is enacted in practice in a large multinational manufacturing company recognized for its LCM work. A qualitative study, with mainly a managerial focus, is conducted based on interviews, workshops, part-time observations, and document studies.

Results and discussion

The literature review demonstrates that the three related research fields provide different accounts of LCM: all apply a holistic environmental perspective, but with different emphases and using largely different research methods. The empirical study shows that integration was a common topic at the studied company and that solutions were often sought in tools and processes. Middle management support proved important, and challenging, in these integration efforts. Challenges identified also included further integrating LCM into departments such as purchasing and sales.

Conclusions

The constant focus on integration at the studied company implies that LCM work is an ongoing effort. Several integration paths are identified: (1) inclusion of sustainability aspects in tools and processes, (2) finding ways to work around certain organizational levels, and (3) using networks and social interaction to create commitment and integration. Although the concept of LCM implies a holistic approach, LCM in practice reveals a lack of a comprehensive overview of LCM-related initiatives and of involved sustainability practitioners within the studied organization.

     

Performance modeling of a manufacturing cell with a single material transporter: An approximation

We consider a flexible manufacturing system with a number of workstations, a single material transporter, and a common storage space of finite capacity. The material handling delay times are explicitly considered in the model and assumed to follow a two-stage Coxian distribution. The material processing times on a workstation also have a two-stage Coxian distribution. The routing of parts within the system follows a Markov chain. An approximate performance model is developed and the results are compared with the exact or simulation results. We also investigate how this performance model compares to a simulation with deterministic routing and processing times. Finally, we study the effect, on the performance measures, of ignoring the material transporter or of modeling the transporter as a central server with aggregation of routing information.     

The properties of global risk networks and corresponding risk management strategies

Global risks interconnect with one another and threaten our society as a highly interdependent system. However, knowledge on how risk materializations influence one another is limited. Thus, this study provides a network model to measure risk interdependence and presents recommendations on the integrative risk management framework.

This study develops a global risk network and calculates its key indicators of structural characteristics. Results show that global risks are closely interconnected and a particular triangle relationship exists among environmental, geopolitical, and societal risks. To improve the resilience of a risk system, the systematic important risks, which are “man-made environmental catastrophes” and “interstate conflict” in this study, should be monitored and controlled. Furthermore, we simplify the risk system by entirely managing risks in the same group based on our reclassification. Our method is considerably effective in detecting upcoming crisis and assists supervisors take timely action to prevent crisis.     

Optimal production control of a service-oriented manufacturing system with customer balking behavior

The great challenge for service-oriented manufacturing (SOM) is how to cope with customer behavior while making decision on production planning and scheduling. In this paper, we consider a single-stage manufacturing system for SOM with impatient customers. In order to represent customer balking behavior caused by backlog, we employ a balking function, which is an arbitrary non-decreasing function of the backlog for characterizing the customer’s response to the backlog. The objective is to find the optimal production policy that minimizes the system cost. The problem is formulated as a Markov decision process. The optimal production policy is proved to be a base-stock policy. The effects of system parameters on the optimal base-stock level are analytically investigated, and the impact of customer balking behavior on the system is illustrated by numerical example in which linear balking function is employed. Numerical example shows that customer balking has a significant impact on the optimal control and the performance measures of the system under the optimal policy.     

Modeling of phenol degradation system using artificial neural networks

Pseudomonas pictorum (NICM-2077) an effective strain used in the biodegradation of phenol was grown on various nutrient compounds which protect the microbes while confronting shock loads of concentrated toxic pollutants during waste water treatment. In the present study the effect of glucose, yeast extract, (NH₄)₂SO₄ and NaCl on phenol degradation has been investigated and a Artificial Neural Network (ANN) Model has been developed to predict degradation. Also the learning, recall and generalization characteristics of neural networks has been studied using phenol degradation system data. The network model was then compared with a Multiple Regression Analysis model (MRA) arrived from the same training data. Further, these two models were used to predict the percentage degradation of phenol for a blind test data. Though both the models perform equally well ANN is found to be better than MRA due to its slightly higher coefficient of correlation, lower RMS error value and lower average absolute error value during prediction.     

An iterative approach to system setup problems in flexible manufacturing systems

System setup problems in flexible manufacturing systems deal with short-term planning problems such as part type selection, machine grouping, operation assignment, tooling, fixture and pallet allocation, and routing. In this article, we consider three of the subproblems: part type selection, machine grouping, and loading. We suggest a heuristic approach to solve the subproblems consistently with the objective of maximizing the expected production rate. The proposed procedure includes routines to generate all possible machine grouping alternatives for a given set of machines, to obtain optimal target workloads for each grouping alternative, and to allocate operations and tools to machine groups. These routines are executed iteratively until a good solution to the system setup problem is obtained. Computational experience is reported.