Can Saygin

Auction-based distributed scheduling and control scheme for flexible manufacturing systems

An auction-based algorithm for real-time scheduling of flexible manufacturing systems with alternate routings is presented. The effectiveness of the proposed framework is demonstrated by comparing it with various priority rules via simulation. The framework was built on a model developed by MacChiaroli and Riemma in 2002. The cost function of the original model was modified to incorporate ‘time’ as the primary criterion. The coefficients in the cost function were calibrated to improve the effectiveness of the approach. A software environment that included various Visual Basic® modules and the simulation package Promodel® were developed to implement the concept. The model was compared with typical priority rules on the basis of average tardiness, average lateness, average due date deviation, utilization balance, average throughput, average wait time and total cost. Analysis of the results showed that the auction-based approach outperformed the priority rules on most performance measures. The study concluded with a discussion on future research on auction-based models and on their application in the area of flexible manufacturing systems.

A Systems Approach to Viable RFID Implementation in the Supply Chain

This article presents a systems approach to RFID deployment in a supply chain from two perspectives: (1) RFID data-based decision-making at all levels of supply chain and (2) communications infrastructure necessary to provide seamless data and information flow. The main contribution of this article is highlighting the interconnection between these two perspectives and the fact that without tackling these issues simultaneously, no viable solution can be developed. Unlike typical articles in the literature, which solely highlight the potential advantages of RFID technologies, this article aims to provide an overview of the basic challenges of deploying RFID systems in supply networks. By providing visibility, effective RFID implementation in a supply chain can bridge the gap between the shop floor and higher level operations. Such a revolutionary concept changes the traditional “linear” structured supply chains into network-centric supply chains. Based on this concept, this article presents a wide range of RFID applications, ranging from shop floor control to inventory management, and discusses technical and research challenges.

Mahalanobis-Taguchi System as a Multi-Sensor Based Decision Making Prognostics Tool for Centrifugal Pump Failures

A novel Mahalanobis Taguchi System (MTS) based fault detection, isolation, and prognostics scheme is presented. The proposed scheme fuses data from multiple sensors into a single system level performance metric using Mahalanobis Distance (MD), and generates fault clusters based on MD values. MD thresholds derived from the clustering analysis are used for fault detection and isolation. When a fault is detected, the prognostics scheme, which monitors the progression of the MD values over time, is initiated. Then, using a linear approximation, time to failure is estimated. The performance of the scheme has been validated via experiments performed on a mono-block centrifugal water pump testbed. The pump has been instrumented with vibration, pressure, temperature, and flow sensors; and experiments involving healthy and various types of faulty operating conditions have been performed. The experiments show that the proposed approach renders satisfactory results for centrifugal water pump fault detection, isolation, and prognostics. Overall, the proposed solution provides a reliable multivariate analysis and real-time decision making tool that 1) fuses data from multiple sensors into a single system level performance metric; 2) extends MTS by providing a single tool for fault detection, isolation, and prognosis, eliminating the need to develop each separately; and 3) offers a systematic way to determine the key parameters, thus reducing analysis overhead. In addition, the MTS-based scheme is process independent, and can easily be implemented on wireless motes1, and deployed for real-time monitoring, diagnostics, and prognostics in a wide variety of industrial environments.

Dissimilarity maximization method for real-time routing of parts in random flexible manufacturing systems

This paper presents a dissimilarity maximization method (DMM) for real-time routing selection and compares it via simulation with typical priority rules commonly used in scheduling and control of flexible manufacturing systems (FMSs). DMM aims to reduce the congestion in the system by selecting a routing for each part among its alternative routings such that the overall dissimilarity among the selected routings is maximized. In order to evaluate the performance of DMM, a random FMS, where the product mix is not known prior to production and off-line scheduling is not possible, is selected for the simulation study. A software environment that consists of a computer simulation model, which mimics a physical system, a C++ module, and a linear program solver is used to implement the DMM concept. In addition to DMM, the simulation study uses two priority rules for routing (i.e., machine) selection and seven priority rules for selecting parts awaiting service at machine buffers. The results show (1) DMM outperforms the other two routing selection rules on production rate regardless of the part selection rule used, and (2) its performance is highly dependent on the part selection rules it is combined with.

Real‐time routing selection for automated guided vehicles in a flexible manufacturing system

Purpose – The purpose of this paper is to present the development of an architecture for real‐time routing of automated guided vehicles (AGV) in a random flexible manufacturing system (FMS).Design/methodology/approach – AGV routing problem is modeled using an evolutionary algorithm‐based intelligent path planning model, which handles vehicle assignments to material handling requests and makes routing decisions with the objective of maximizing the system throughput. The architecture is implemented on a 3‐layer software environment in order to evaluate the effectiveness of the proposed model.Findings – The proposed architecture, along with the evolutionary algorithm‐based routing model, is implemented in a simulated FMS environment using hypothetical production data. In order to benchmark the performance of the path planning algorithm, the same FMS model is run by traditional dispatching rules. The analysis shows that the proposed routing model outperforms the traditional dispatching rules for real‐time rou...

RFID data-based inventory management of time-sensitive materials

In this paper, an adaptive inventory management model, which is founded on a forecasting algorithm that utilizes RFID-based state and event data for tracking and dispatching of time sensitive materials in a manufacturing facility, is presented. The impact of integrating RFID technologies with inventory control on the shop floor is discussed. This study compares a traditional, static inventory model with the proposed model on the basis of cost savings, inventory and waste reduction, and decision making complexity. The validity of the proposed model is demonstrated in a simulation environment, which also demonstrates the overall benefits and effectiveness of RFID technologies in providing low cost manufacturing solutions, reduced inventory levels, and lower overall waste.

A testbed architecture for Auto‐ID technologies

Purpose – This paper presents an overview on the Auto‐ID (Automatic Identification) technologies testbed that has been established at the University of Missouri‐Rolla (UMR) with the objective of supporting research, development, and implementation of Auto‐ID technologies in network‐centric manufacturing environments.Design/methodology/approach – UMRs Auto‐ID testbed uses a unique hardware‐in‐the‐loop simulation methodology, which integrates decision‐making model development with the design of networking topology and data routing/scheduling schemes, in order to develop, test, and implement viable Auto‐ID solutions. The methodology is founded on a 3‐level integrated model: controller simulation, distributed controller simulation, and distributed controller simulation with hardware‐in‐the‐loop.Findings – This paper discusses two case studies that highlight the effective use of RFID technology, its potential advantages, challenges, and deficiencies stemming from particular applications. These applications in...

Interference mitigation and read rate improvement in RFID‐based network‐centric environments

Purpose – This paper investigates interference mitigation and read rate improvement by using novel power control and graph‐based scheduling schemes for radio frequency identification (RFID) systems.Design/methodology/approach – The first method is a distributed power control (DPC) scheme proposed as an alternative to listen‐before‐talk (LBT) for RFID systems specified under CEPT regulations. The DPC algorithm employs reader transmission power as the system control variable to achieve a desired read range and read rate without causing unwanted interference. The second approach is graph‐based scheduling, which uses a graph coloring‐based approach to temporally separate readers with overlapping interrogation zones. The scheduling of the timeslots is carried out so as to offer better efficiency for each reader.Findings – This paper shows that power control, graph theory, collision probability analysis along with timeslot scheduling schemes can be widely adapted to solve general RFID problems. The study shows ...

Impact of reputation information sharing in an auction-based job allocation model for small and medium-sized enterprises

This research investigates the impact of reputation information sharing in an auction-based job allocation system using a multi-agent based simulation model based on three performance measures: economic efficiency, throughput index, and penalty index. Two forms of reputation information sharing systems, dyadic and public, were implemented and studied. Dyadic reputation systems deal with one-to-one information sharing, while public reputation systems deal with many-to-many information sharing. The paper proposes a hybrid auction mechanism, which is a combination of the sealed bid and reverse auction mechanisms. Analysis of the simulation results shows that reputation information sharing benefits the system tremendously by increasing the overall economic efficiency and throughput index, while decreasing the penalty index of the system. The results also show that as the significance of reputation in the market increases, the benefits realised in terms of economic efficiency and throughput index also increases.

Special issue on ‘RFID-Enabled Manufacturing: Insights and Lessons from Industrial Cases’

Radio frequency identification (RFID) has received a great deal of attention for its potential ability to perform non-contact object identification and to provide visibility at the point of use in a variety of different industries. Over the last several years, we have seen various applications in the manufacturing industry ranging from inventory monitoring to tool tracking to automatic collection and processing of real-time production data aiming to reduce and avoid the error-prone, tedious manual activities. We have seen that RFID data can be used to generate valuable information, which can reduce inventory levels, cut down lead times, and facilitate enterprise-wide operational visibility throughout the entire product lifecycle across the supply chain. Real-time operational visibility and traceability closes the loop of production planning and control facilitating adaptive decision making. There have been companies who have initiated exploratory efforts for RFID-enabled manufacturing solutions for their day-to-day operations, some on a small scale and some as pilot implementations. Many equipment vendors have developed their RFID solutions and introduced them to the market. Worldwide efforts are in place to develop standards for RFID development and deployment. In spite of all these focused efforts, the progress of achieving the potential benefits of RFID in manufacturing has been slow. The aim of this Special Issue is to solicit and collect valuable insights gained and lessons learned through real-life experiences, including success stories and failures. Eight papers have been selected for inclusion in this Special Issue. It is hoped that this Special Issue inspires more interest and draws more attention to researchers and practitioners in the field. The first paper by Zhu et al. presents a case study on RFID application in a typical household appliance manufacturing environment, in parallel to the barcode technology. While benefits have been reported, several practical issues have also been recognised for those who are considering similar applications. The second paper by Wang, Kowk and Ip deals with the application of RFID for quality evaluation system design for the wine industry. A method of using RFID-enabled real-time data to provide quality evaluation of the final wine has been discussed. The quality evaluation system can discover accidents in time to reduce losses and prevent counterfeit. One-of-a-Kind-Production (OKP) is a non-repetitive manufacturing mode that produces customised products with unique components. Due to the varying production requirements and inadequate operation experience, the unique components and related operations often cause great dynamics in the workshop execution process. The third paper by Wang et al. presents an easy-to-deploy and simple-to-use RFIDenabled manufacturing execution system (MES) to achieve such real-time control for typical OKP workshops. Through the case study in a mould and die manufacturing company, technical, social and organisational issues have been reported. The fourth paper by Chen employs a modular design to develop a flexible manufacturing system (FMS) cell controller based on RFID. This article discusses the feasibility of applying this method to a real production line. It is intended that the proposed method of developing a cell controller could serve as a reference template for tracking and control, facilitating the rapid introduction and application of RFID technology into industrial FMS in the future. The fifth paper by Dai et al. reports on an industrial case study about the RFID implementation project at a typical small-and-medium sized (SME) engine valve manufacturer. The company adopted RFID-enabled shop-floor manufacturing solutions across its entire operations with little experience in the use of information systems/technology. Based on RFID-enabled real-time shop-floor data, the company has extended the efforts in setting up and integrating MES and an enterprise resource planning system. The success of this case company demonstrates that RFID is not just for automotive giants but also practically useful for typical SME automotive part suppliers. The sixth paper by Huang et al. reported on the development and application of RFID-enabled realtime monitoring system (RRMS) to improve visualisation and controllability of the painted body storage (PBS) in a Chinese multi-purpose vehicle manufacturer. RRMS improves the efficiency of operation and makes PBS into a transparent, open and controllable system. Moreover, integrated with MES, RRMS International Journal of Computer Integrated Manufacturing Vol. 25, No. 1, January 2012, 1–2