Fu-Kwun Wang

An evaluation of freight consolidation policies in global third party logistics

The collaborative integration with global third party logistics (3PL) to execute physical distribution dictates the success of any global supply chain (GSC) application. In an overall effort to minimize the system-wide cost, global 3PL can apply various consolidation policies to maximize the utilization of expensive transportation such as aircraft. Freight consolidation has received considerable attention in recent years, but the application of consolidation policies by integrated global 3PL under an e-business model is rarely discussed. The emergence of mass customization has challenged integrated logistics providers to adjust their consolidation policies in order to simultaneously minimize the cost and fulfill the service commitments. This paper examines a special class of freight consolidation at an integrated global logistics company in GSC. A mathematical programming model has been developed to assist the evaluation of consolidation policies. The computational results reveal a substantial cost saving and a service level improvement of about 20% as a consequence of implementing a collaborative consolidation policy.

Using principal component analysis in process performance for multivariate data

Quality measures can be used to evaluate a processs performance. Analyzing related quality characteristics such as weight, width and height can be combined using multivariate statistical techniques. Recently, multivariate capability indices have been developed to assess the process capability of a product with multiple quality characteristics. This approach assumes multivariate normal distribution. However, obtaining these distributions can be a complicated task, making it difficult to derive the needed confidence intervals. Therefore, there is a need to develop one robust method to deal with the process performance on non-multivariate normal data. Principal component analysis (PCA) can transform the high-dimensional problems into lower dimensional problems and provide sufficient information. This method is particularly useful in analyzing large sets of correlated data. Also, the application of PCA does not require multivariate normal assumption. In this study, several capability indices are proposed to summarize the process performance using PCA. Also, the corresponding confidence intervals are derived. Real-world case studies will illustrate the value and power of this methodology.

Simulation analysis of dispatching rules for an automated interbay material handling system in wafer fab

Here, the performance evaluation of a double-loop interbay automated material handling system (AMHS) in wafer fab was analysed by considering the effects of the dispatching rules. Discrete event simulation models based on SIMPLE++ were developed to implement the heuristic dispatching rules in such an AMHS system with a zone control scheme to avoid vehicle collision. The layout of an interbay system is a combination configuration in which the hallway contains double loops and the vehicles have double capacity. The results show that the dispatching rule has a significant impact on average transport time, waiting time, throughput and vehicle utilization. The combination of the shortest distance with nearest vehicle and the first encounter first served rule outperformed the other rules. Furthermore, the relationship between vehicle number and material flow rate by experimenting with a simulation model was investigated. The optimum combination of these two factors can be obtained by response surface methodology.

A new model with bathtub-shaped failure rate using an additive Burr XII distribution

Abstract It is a common situation that the failure rate function has a bathtub shape for many mechanical and electronic components. A simple model based on adding two Burr XII distributions is presented for modeling this type data. The graphical estimation on probability paper is illustrated, and examples of its usage are presented. The Akaike Information Criterion was used for judging the adequacy of the models presented for the numerical examples. It can be seen that the proposed model is a very competitive model for describing the bathtub-shaped failure rate lifetime data.

CAPABILITY INDEX USING PRINCIPAL COMPONENTS ANALYSIS

Multivariate process capability indices have recently been developed to assess the capability of processes having multiple characteristics. When quality variables are related characteristics, analysis should be based on a multivariate statistical techni..

Applying Six-Sigma to Supplier Development

Supply chain management (SCM) adopts a systematic and integrative approach to managing the operations and relationships among different parties in supply chains. To implement SCM successfully involves a lot of issues. One of the major issues is supplier development. On the other hand, studies have investigated how quality management can be employed in SCM to improve the performance of various issues in the whole supply network. This study will develop an application guideline for the assessment, improvement, and control of quality in SCM using Six-Sigma improvement methodology. Improvements in the quality of all supply chain processes lead to cost reductions as well as service enhancements. In our approach, supplier evaluation is conducted by principal component analysis. The measurement data from 25 suppliers of a PC manufacturer in Taiwan, including two major input variables and three major output variables, will be used for demonstration.

Learning curve analysis in total productive maintenance

An apparatus which serves to control automatically the speed of a pump according to the temperature of the oil being pumped from a reservoir. The controller is comprised of a parallel bank of thermal switches each connected to its dropping load resistor through a series isolation relay which places the load on a motor which drives the oil pump directly related to the viscosity of the oil in the reservoir.

Maximum likelihood estimation of the Burr XII parameters with censored and uncensored data

Abstract This paper presents the methodology for obtaining point and interval estimates of the parameters of the Burr Type XII distribution with multiple-censored and singly-censored data (Type I censoring or Type II censoring) as well as complete data, using the maximum likelihood method. The basis is the likelihood expression for multiple-censored data. The other types of censoring and complete data are treated as special cases. A FORTRAN language program was used. Some illustrative examples are included.

Evaluating the efficiency of implementing total productive maintenance

Abstract Total Productive Maintenance (TPM) has been widely recognized as a strategic weapon for improving manufacturing performance. This has also been successfully implemented in many organizations. The evaluation of TPM efficiency can assist factories in improving their operations across a variety of dimensions. In particular, it aids factories in monitoring their performance in comparison with other factories. Effective benchmarks of high performance and efficient cluster are identified for improving the factories in the other groups. Here, Data Envelopment Analysis (DEA) is used to evaluate the efficiency score for when the utility function considers its many attributes. A prediction model by the multiple regression method is obtained. This regression equation can be used to obtain the expected efficiency score for checking the performance of implementing TPM. Finally, the proposed methodology can identify a peer group of efficient factories against which to benchmark. The actual improvement process may involve identifying the operating practices and procedures of the benchmark factories and engaging in re-engineering programs.

Connecting transport AMHS in a wafer fab

Automated material handling system (AMHS) plays a significant role in wafer fabrication. In this paper, a new concept of an automated material handling system in a 300 mm wafer fabrication, called the connecting transport AMHS, is proposed. It can accomplish the wafer moving tasks by using different types of vehicles between bays and, within each bay, by a single system with interconnected lines. In the connecting transport system, the time that is spent waiting for an empty vehicle is eliminated effectively, and the WIP level can be reduced. Four different vehicle types are found and their operational issues are also discussed. Furthermore, three different combinations of vehicles are found and the AMHS for a 300 mm wafer fab can be one of the above three methods, or any mixture of these methods. A simple mathematical model is used to determine the minimum number of vehicles for the different connecting transports.