Kenneth H. Doerr

Impact of material flow policies and goals on job outcomes

A manual production line was examined for effects of different material flow policies and 3 different goal-setting policies. The line used a push system, where workers work at their own pace (assuming available work ) and pass work to the next station as soon as the work is completed, and a pull system, where workers pass work only when the next worker needs it. Three different goal-setting policies involved no specified goals, individual goals, or group goals confounded with monetary incentives and feedback. Measurements were taken from unobtrusive videotaping and worker questionnaires. Analyses indicated productivity increased approximately 25% when group goals were matched to a pull policy (compared to a push policy with no specified goals). Other results relating to productivity and job satisfaction are discussed.

MEASUREMENT ISSUES IN PERFORMANCE-BASED LOGISTICS

Performance Based Logistics (PBL) is an acquisition reform that is intended to improve weapon systems logistics by reducing cost, improving reliability, and reducing footprint. PBL is an extension of a broad process of rationalizing and, in many cases, outsourcing government services. As with other examples of governmental service outsourcing, measurement issues arise in the gap between governmental objectives and service measurement, and in the contrast between clear profit-centered vendor metrics, and more complex mission-oriented governmental metrics. Beyond this, however, PBL presents new challenges to the relationship between governmental agencies and their service vendors. In many cases, weapons systems logistical support involves levels of operational risk that are more difficult to measure and more difficult to value than other government services. We discuss the implications of operational risk and other measurement issues on PBL implementation.

A worker-based approach for modeling variability in task completion times

Abstract Three sources of variability in task completion times are identified: the task itself, the worker performing the task, and the environment where the task is performed. Although all three sources might play a role, for practical purposes researchers seek a parsimonious model of variability in task completion times which identifies the most significant source. It is typically assumed that the most significant sources are the task itself or the environment where the task is performed. In this paper we investigate the notion that the worker performing the task may be the most significant source of variability in task completion times, and propose a modeling approach for this situation. We also present the results of a field experiment that support the proposed modeling approach.

Work flow policy and within-worker and between-workers variability in performance

Work flow policies are shown to induce a change in average between-workers variability (worker heterogeneity) and within-worker variability in performance times. In a laboratory experiment, the authors measured the levels of worker heterogeneity and within-worker variability under an individual performance condition, a work sharing condition, and a fixed assignment condition. The work sharing policy increased the levels of worker heterogeneity and worker variability, whereas the fixed assignment policy decreased them. These effects, along with work flow policy main effects on mean performance times and variability are examined. This article represents an initial step in understanding effects that may be important in the selection of an operating policy, the ignorance of which may lead to costly misestimates of performance.

In-house development of scheduling decision support systems: case study for scheduling semiconductor device test operations

Most manufacturing processes can benefit from an automated scheduling system. However, the design of a fast, computerised scheduling system that achieves high-quality results and requires minimal resources is a difficult undertaking. Efficient scheduling of a semiconductor device test facility requires an information system that provides good schedules quickly. Semiconductor device testing is the last stage of the long semiconductor manufacturing process, and therefore is subjected to customer service pressures. The cost of an off-the-shelf computerised scheduling system may be prohibitive for many companies. In addition, many companies are taken aback by other characteristics of off-the-shelf scheduling systems, such as code confidentiality, maintenance costs, and failure rates. We draw upon the literature and our field case to discuss some of the trade-offs between in-house development and off-the-shelf acquisition of software. We describe the in-house design and implementation of a scheduling decision support system for one device test facility. Using the design and implementation process of this system as a case study, we discuss how one facility uses in-house design of systems in a strategic way, as a competitive capability.

A design of experiments approach to readiness risk analysis

We develop a simulation model to aid in identifying and evaluating promising alternatives to achieve improvements in weapon system-level availability when services for system components are outsourced. Two outcomes are valued: improvements in average operational availability for the weapon system, and reductions in the probability that operational availability of the weapon system falls below a given planning threshold (readiness risk). In practice, these outcomes must be obtained through performance-based agreements with logistics providers. The size of the state space, and the non-linear and stochastic nature of the outcomes, precludes the use of optimization approaches. Instead, we use designed experiments to evaluate simulation scenarios in an intelligent way. This is an efficient approach that enables us to assess average readiness and readiness risk outcomes of the alternatives, as well as to identify the components and logistics factors with the greatest impact on operational availability

Design, coordination and control of hybrid factories

In this paper, the authors elaborate the notion of a hybrid factory: factories in which some production capacity is dedicated to process‐oriented manufacturing, and some is dedicated to product‐oriented manufacturing. We present the results of a field study of one such factory and, using it as an example, develop a list of eight issues that may arise as a part of implementing and managing a hybrid factory. Where possible, we tie these issues into existing research streams. We show how our field site addressed these issues and, based on their experience, suggest new areas for investigation by researchers. An examination of the way our field site implemented and managed a hybrid factory also provides insight for managers facing similar situations.

Bi-criteria risk analysis of domain-specific and cross-domain changes in complex systems

Abstract Government and not-for-profit organizations measure success in terms of their ability to promote an organizational mission. Complex assets in such organizations are acquired in a budget-allocation process which reflects mission priorities. So, complex assets in such an environment must be managed so that availability of the asset is sufficient to support mission objectives as planned. But cost must also be contained within the budget plan, or other mission objectives may suffer. Hence, an objective in such environments is to simultaneously control (1) the risk that percent-availability will fall below a minimum planning threshold α , and control (2) the risk that cost will exceed the planned budget β . This problem is especially difficult because the two risks are negatively correlated. In this paper we examine this bi-criteria risk minimization problem, for an organization in which the departments (domains) of the organization must compete for scarce resources to achieve organizational objectives. We develop a model that can be used to assess bi-criteria risk of single-domain proposals, and a ranking-and-selection procedure which can be used to choose between those proposals. We then conduct a limited search of solutions which involve linear combinations of the proposals, in order to investigate the potential benefits of ‘breaking silos’ and ‘cooperation’ across domains. Results suggest that for complex systems at least, cross-domain solutions are not always superior to single-domain solutions, and that integrated system models are needed to properly evaluate single-domain or cross-domain solutions.

An analysis of STOM (ship to objective maneuver) in sea based logistics

Operational Maneuver From the Sea (OMFTS) and its implementing concept, Sea Based Logistics (SBL) stress the need for logistically supporting forces ashore directly from a sea base. This study analyzes the capability of a current LHD-class amphibious ship to sustain a force deployed ashore through direct Ship-To-Objective Maneuver (STOM) of replenishment and logistics support. We have developed a simulation model that can evaluate performance of STOM operations using an LHD-class amphibious ship as a sea base. Results indicate a substantial increase in the number of aircraft, and reliability of those aircraft, and/or a substantial reduction in sustainment requirements are needed in order to successfully accomplish the scenarios used in this study. The results of this study could support the design of future LHD-class ships.

Fuel Sharing in Expeditionary Operations

Abstract Expeditionary units operate beyond the normal supply chain. We examine a situation in which expeditionary units are dispersed and moving forward to achieve some mission objective. The logistics decision must be made: should resources (fuel) be shared between those expeditionary units. Our criterion is mission risk, or the probability the expeditionary mission succeeds. Mission risk is modeled as a function of both logistics risk and operational risk. We present a model of fuel sharing which incorporates this balance of risks and we demonstrate the effectiveness of fuel sharing in an extended numerical example, based on historical data from the Ardennes campaign in WWII.