Doraid Dalalah and Wasfi Al-Rawabdeh
The purpose of this paper is to benchmark alternatives of decision problems that include risk and uncertainty considering different risk attitudes via a new data envelopment…
Abstract
Purpose
The purpose of this paper is to benchmark alternatives of decision problems that include risk and uncertainty considering different risk attitudes via a new data envelopment analysis (DEA) decision model.
Design/methodology/approach
A new utility function of strict bounds is applied in a data envelopment model to evaluate all possible stochastic alternatives (i.e. gambles). The amount of risk in the alternatives is measured by a newly introduced risk ratio (RR). Each alternative is considered as a decision making unit (DMU). The alternatives efficiency frontier is found via linear optimization of the DEA model.
Findings
In contrast to literature studies of binary decision alternatives, here, benchmarking is conducted to evaluate multiple decision alternatives with unbounded utility of the payoffs along with a new DEA decision model. Different surveys and studies have been used to validate the model. DEA could demonstrate the ability to uncover relationships that remain hidden for other methodologies. The resulting rankings remarkably conform to those elicited by subjects.
Social implications
Individuals of different wealth backgrounds evaluate risky decision problems differently.
Originality/value
The paper contributes to the existing research by benchmarking multiple alternatives as compared to the literature research which usually assesses binary problems. Instead of using explicit utilities, the model implements the efficiencies along with a new utility function and a new RR. The introduction of DEA to such a decision field is found to be successful in benchmarking numerous alternatives under different risk attitudes.
Details
Keywords
The purpose of this paper is to assess and benchmark Six Sigma strategies in services sector, namely, the telecom field, by establishing tables of fallouts of non-conforming…
Abstract
Purpose
The purpose of this paper is to assess and benchmark Six Sigma strategies in services sector, namely, the telecom field, by establishing tables of fallouts of non-conforming services and their associated costs along with a custom data envelopment model for benchmarking the different strategic alternatives.
Design/methodology/approach
Under normality assumption, process fallout in Six Sigma is around 0.002/3.4 part per million for a centered/shifted process. By introducing Six Sigma to applications in services sector, normality assumption may no longer be valid; hence, fallouts of non-normal attributes are computed for different one-sided quality levels. The associated costs of strategy deployment, fallout and transaction completion are all considered. Data envelopment analysis model is also established to benchmark the Six Sigma strategic plans. The strategies are detailed down to processes and to quality characteristics which constitute the decision-making units. The efficiency of each service unit is computed using both CCR and super efficiency models.
Findings
The amount of efforts/costs needed to reduce the variation in a service may differ according to the targeted quality level. For the same Six Sigma quality level, services demonstrate different performance/efficiencies and hence different returns. In some scenarios, moderate quality levels could present high efficiencies as compared to services of higher levels. It was also found that the required improvement is less in the case of Log-normal as compared to normal distributions at some quality levels. This observation is also noted across the presented distributions of this study (Normal, Log-normal, Exponential, Gamma and Weibull).
Social implications
The deployment of Six Sigma in services is mostly found in time-related concepts such as timeliness of billing, lifetimes in reliability engineering, queueing theory, healthcare and telecommunication.
Originality/value
The paper contributes to the existing research by presenting an assessment model of Six Sigma strategies in services of non-normal distributions. Strategies of different quality levels present diverse efficiencies; hence, higher quality levels may not be the best alternatives in terms of the returns on investment. The computed fallout rates of the different distributions can serve as palm lines for further deployment of Six Sigma in services. Besides, the combination of optimization and Six Sigma analysis provides additional benchmarking tool of strategic plans in both manufacturing and services sector.
Omar Bataineh, Tarek Al-Hawari, Hussam Alshraideh and Dorid Dalalah
The purpose of this paper is to improve production effectiveness of equipment by facilitating the implementation of the key principles of total productive maintenance (TPM).
Abstract
Purpose
The purpose of this paper is to improve production effectiveness of equipment by facilitating the implementation of the key principles of total productive maintenance (TPM).
Design/methodology/approach
A sequential TPM-based scheme consisting of 13 procedural steps is proposed. The steps cover the basic aspects of a generic improvement system, i.e. planning, implementation, checking, corrective action and control.
Findings
The proposed scheme was effective in increasing the overall equipment effectiveness by 62.6 percent over a nine-month period only. This was a direct reflection of improvements in equipment availability, efficiency and product quality. A positive feedback regarding the smooth implementation of the scheme was also received from the responsible maintenance staff.
Research limitations/implications
The proposed scheme is intended mainly to the manufacturing industrial sector, which utilizes failure-prone equipment in running operations.
Originality/value
This study presents an original scheme that tries to avoid the many barriers of success frequently encountered during the implementation of TPM schemes, as reported in the literature. This scheme is unique in integrating between 5S and safety, health and environment initiatives, by capitalizing on the close relation between the two initiatives, and simplifying procedures for measuring how well the two initiatives are implemented in an organization in one score card. Different from previous studies, the scheme treats both “education and training” and 6S as a foundation to the core TPM principles.