Paul M. Griffin

Coordinated supply chain management

Abstract Historically, the three fundamental stages of the supply chain, procurement, production and distribution, have been managed independently, buffered by large inventories. Increasing competitive pressures, and market globalization are forcing firms to develop supply chains that can quickly respond to customer needs. To remain competitive, these firms must reduce operating costs while continuously improving customer service. With recent advances in communications and information technology, as well as a rapidly growing array of logistics options, firms have an opportunity to reduce operating costs by coordinating the planning of these stages. In this paper, we review the literature addressing coordinated planning between two or more stages of the supply chain, placing particular emphasis on models that would lend themselves to a total supply chain model. Finally, we suggest directions for future research.

Effectiveness of Fluoride in Preventing Caries in Adults

To date, no systematic reviews have found fluoride to be effective in preventing dental caries in adults. The objective of this meta-analysis was to examine the effectiveness of self- and professionally applied fluoride and water fluoridation among adults. We used a random-effects model to estimate the effect size of fluoride (absolute difference in annual caries increment or relative risk ratio) for all adults aged 20+ years and for adults aged 40+ years. Twenty studies were included in the final body of evidence. Among studies published after/during 1980, any fluoride (self- and professionally applied or water fluoridation) annually averted 0.29 (95%CI: 0.16–0.42) carious coronal and 0.22 (95%CI: 0.08–0.37) carious root surfaces. The prevented fraction for water fluoridation was 27% (95%CI: 19%–34%). These findings suggest that fluoride prevents caries among adults of all ages.

Robot exploration with combinatorial auctions

We study how to coordinate a team of mobile robots to visit a number of given targets in a partially unknown terrain. Robotics researchers have studied single-item auctions to perform this exploration task but these do not make synergies between the targets into account. We therefore design combinatorial auctions, propose different combinatorial bidding strategies and compare their performance with each other, as well as to single item auctions and an optimal centralized mechanism. Our computational results in teambots, a multi-robot simulator, indicate that combinatorial auctions generally lead to significantly superior team performance than single-item auctions, and generate very good results compared to an optimal centralized mechanism.

Estimating Rates of New Root Caries in Older Adults

Although older adults are keeping their teeth longer, no national data are available on new caries in this age group. To characterize the extent of caries among older adults, we systematically reviewed studies on root caries incidence, increment, attack rate, and annual total (root + coronal) caries increment. We used a random-effects model to estimate annual summary measures and their 95% confidence intervals (CI) and tested for heterogeneity. For the 9 studies reporting root caries incidence, the summary measure equaled 23.7% (CI = 17.1–30.2%). For the 9 studies reporting root caries increment, the summary measure was 0.47 surfaces (CI = 0.34–0.61). For the 7 studies reporting total caries increment, the summary measure equaled 1.31 surfaces (95% CI = 1.01–1.61 surfaces). Because of heterogeneity, summary measures should be interpreted with caution. This research suggests, however, that older adults experience high rates of new caries and could benefit from caries-prevention programs.

Supplier- and buyer-driven channels in a two-stage supply chain

In this paper we explore the impact of power structure on price, sensitivity of market price, and profits in a two-stage supply chain with a single-product, -supplier and -buyer. We develop and analyze the case where the supplier has dominant bargaining power and the case where the buyer has dominant bargaining power, and consider a pricing scheme for the buyer that involves both a multiplier and a constant mark up. We show that it is optimal for the buyer to set the mark-up to zero and use only a multiplier and that the market price and its sensitivity are higher when operational costs (namely distribution and inventory) exist. We also observe that the sensitivity of the market price increases nonlinearly as the wholesale price increases, and derive a lower bound for it. Through experimental analysis, we show that marginal impact of increasing shipment cost and carrying charge (interest rate) on prices and profits are decreasing in both cases.

Generation of uniquely encoded light patterns for range data acquisition

Abstract A method is presented for generating an encoded pattern which may be used for a special structured lighting system. This pattern consists of a matrix of colored circles which is projected onto a scene by backlighting. A single camera is used to image the projected colored light beams, and range data for the object are obtained. Because the light pattern is encoded, the correspondence between the projected beams from the pattern and imaged beams is easily determined, and hence range data may be solved for quickly. Further, this method may be used in dynamic environments.

Burden of oral disease among older adults and implications for public health priorities.

Dental disease is largely preventable. Many older adults, however, experience poor oral health. National data for older adults show racial/ethnic and income disparities in untreated dental disease and oral health-related quality of life. Persons reporting poor versus good health also report lower oral health-related quality of life. On the basis of these findings, suggested public health priorities include better integrating oral health into medical care, implementing community programs to promote healthy behaviors and improve access to preventive services, developing a comprehensive strategy to address the oral health needs of the homebound and long-term-care residents, and assessing the feasibility of ensuring a safety net that covers preventive and basic restorative services to eliminate pain and infection.

Path planning for a mobile robot

Two problems for path planning of a mobile robot are considered. The first problem is to find a shortest-time, collision-free path for the robot in the presence of stationary obstacles in two dimensions. The second problem is to determine a collision-free path (greedy in time) for a mobile robot in an environment of moving obstacles. The environment is modeled in space-time and the collision-free path is found by a variation of the A* algorithm. >

Coordination of Marketing and Production for Price and Leadtime Decisions

We study a firm which serves customers that are sensitive to quoted price and leadtime, with pricing and leadtime decisions being made by the marketing and production departments, respectively. We analyze the inefficiencies created by the decentralization of the price and leadtime decisions. In the decentralized setting, the total demand generated is larger, leadtimes are longer, quoted prices are lower, and the firms profits are lower as compared to the centralized setting. We show that coordination can be achieved using a transfer price contract with bonus payments. We also provide insights on the sensitivity of the optimal decisions with respect to market characteristics, sequence of decisions and the firms capacity level.

Pricing and scheduling decisions with leadtime flexibility

This paper studies a problem faced by a manufacturer who has the ability to set prices to influence demand, reject orders, and set leadtimes or due-dates for accepted orders. We present decision models that integrate pricing and production decisions for the cases where the manufacturer charges the same price or different prices to different customers. Through numerical analyses, we present insights regarding the benefits of price customization, leadtime, and inventory flexibilities, in various demand environments.