24 research outputs found

    Bargaining power and supply base diversification

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    In this paper, the authors examine a supply base diversification problem faced by a buyer who periodically holds auctions to award short term supply contracts among a cohort of suppliers (i.e., the supply base). To mitigate significant cost shocks to procurement, the buyer can diversify her supply base by selecting suppliers from different regions. The authors find that the optimal degree of supply base diversification depends on the buyer’s bargaining power, i.e., the buyer’s ability to choose the auction mechanism. At one extreme, when the buyer has full bargaining power and thus can dictatorially implement the optimal mechanism, she prefers to fully diversify. At the other extreme, when the buyer uses a reverse English auction with no reserve price due to her lack of bargaining power, she may consider protecting herself against potential price escalation from cost-advantaged suppliers by using a less diversified supply base. The authors find that in general the more bargaining power the buyer has to control price escalation from cost-advantaged suppliers the more she prefers a diversified supply base. This insight is shown to be robust to correlation between regional costs, asymmetry across regions, and intermediate levels of bargaining power.supply base diversification; supplier; buyer; procurement; bargaining

    Bargaining Power and Supply Base Diversification

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    We examine a supply base diversification problem faced by a buyer who periodically holds auctions to award short term supply contracts among a cohort of suppliers (i.e., the supply base). To mitigate significant cost shocks to procurement, the buyer can diversify her supply base by selecting suppliers from different regions. We find that the optimal degree of supply base diversification depends on the buyer’s bargaining power, i.e., the buyer’s ability to choose the auction mechanism. At one extreme, when the buyer has full bargaining power and thus can dictatorially implement the optimal mechanism, she prefers to fully diversify. At the other extreme, when the buyer uses a reverse English auction with no reserve price due to her lack of bargaining power, she may consider protecting herself against potential price escalation from cost-advantaged suppliers by using a less diversified supply base. We find that in general the more bargaining power the buyer has to control price escalation from cost-advantaged suppliers the more she prefers a diversified supply base. This insight is shown to be robust to correlation between regional costs, asymmetry across regions, and intermediate levels of bargaining power.http://deepblue.lib.umich.edu/bitstream/2027.42/61192/1/1118_Beil.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/61192/4/1118r_Beil.pd

    Simultaneously Managing Procurement Costs and Risks.

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    The average US manufacturer spends 40-60% of its revenue to procure goods and services. Transcending its more tactical beginnings in vertically integrated firms, today the procurement function serves as a vital gatekeeper to low-cost and low-risk inputs for a firm. Strategic procurement involves operational processes such as supplier qualification screening to identify capable suppliers and also economic processes such as auctions and mechanism design to negotiate terms and prices with suppliers. Reflecting these challenges, the dissertation research studies how companies can simultaneously manage procurement costs and risks. The dissertation consists of three essays. The first essay adopts an optimal mechanism analysis to study how a buyer can best use a reverse auction in combination with supplier qualification screening processes to determine which qualified new supplier to contract with. The main takeaway for practitioners is that the standard industrial practice of fully qualifying all suppliers before the auction can be improved upon by judiciously delaying all or part of the qualification screening process until after the auction. The second essay extends the insights of the first essay to a setting where a buyer conducts an auction with her qualified incumbent supplier and a possibly unqualified entrant, and shows that the incumbent will strategically drop out of the auction early to forestall a bidding war if the buyer delays the entrant's qualification screening until after the auction. The third essay examines how a buyer can choose suppliers from different geographic regions to mitigate region-specific cost shocks to ``non-price costs" covering logistics, tariffs, shipping insurance and commissions. It shows that the buyer's optimal diversification decision depends on her degree of bargaining clout, i.e., her ability to impose auction mechanisms to curtail suppliers' windfall profit-taking. The more bargaining power the buyer has, the more she prefers a diversified supply base.Ph.D.Business AdministrationUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/64797/1/wanzhixi_1.pd

    Complementary assets as pipes and prisms: Innovation incentives and trajectory choices

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108073/1/smj2159.pd

    Distribution Channel Choice and Divisional Conflict in Remanufacturing Operations

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    We consider a firm consisting of two divisions, one responsible for designing and manufacturing new products and the other responsible for remanufacturing operations. The firm will sell these new and remanufactured products either directly to the consumer (direct selling) or through an independent retailer (indirect selling). Our study demonstrates that a firm’s organizational structure can affect its marketing decisions. Specifically, a decentralized firm with separate manufacturing and remanufacturing divisions can benefit from indirect selling with higher firm profit, supply chain profit, and total consumer demand than direct selling. Moreover, this structure also induces a remanufacturable product design. In contrast, a centralized firm in which the manufacturing and remanufacturing divisions are consolidated is intuitively better off by choosing direct selling than indirect selling. Furthermore, we show that, surprisingly, when the focal firm sells through an independent retailer, a decentralized internal structure can result in higher supply chain profit than a centralized internal structure. We further investigate the case of dual dedicated channels and conclude that, while direct selling of remanufactured products and indirect selling of new products can better induce a remanufacturable product design and higher supply chain profit, it is not in the best interest of the firm in terms of total sales and firm profit

    Estimation of Reference Voltages for Time-difference Electrical Impedance Tomography

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    Model and analysis of labor supply for ride-sharing platforms in the presence of sample self-selection and endogeneity

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    Ministry of Education, Singapore under its Academic Research Funding Tier

    High‐Efficiency Graphene‐Oxide/Silicon Solar Cells with an Organic‐Passivated Interface

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    A breakthrough in graphene-oxide/silicon heterojunction solar cells is presented in which edge-oxidized graphene and an in-plane charge transfer dopant (Nafion) are combined to form a high-quality passivating contact scheme. A graphene oxide (GO):Nafion ink is developed and an advanced back-junction GO:Nafion/n-Si solar cell with a high-power conversion efficiency (18.8%) and large area (5.5 cm2) is reported. This scalable solution-based processing technique has the potential to enable low-cost carbon/silicon heterojunction photovoltaic devices

    Morphological diversity of single neurons in molecularly defined cell types.

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    Dendritic and axonal morphology reflects the input and output of neurons and is a defining feature of neuronal types1,2, yet our knowledge of its diversity remains limited. Here, to systematically examine complete single-neuron morphologies on a brain-wide scale, we established a pipeline encompassing sparse labelling, whole-brain imaging, reconstruction, registration and analysis. We fully reconstructed 1,741 neurons from cortex, claustrum, thalamus, striatum and other brain regions in mice. We identified 11 major projection neuron types with distinct morphological features and corresponding transcriptomic identities. Extensive projectional diversity was found within each of these major types, on the basis of which some types were clustered into more refined subtypes. This diversity follows a set of generalizable principles that govern long-range axonal projections at different levels, including molecular correspondence, divergent or convergent projection, axon termination pattern, regional specificity, topography, and individual cell variability. Although clear concordance with transcriptomic profiles is evident at the level of major projection type, fine-grained morphological diversity often does not readily correlate with transcriptomic subtypes derived from unsupervised clustering, highlighting the need for single-cell cross-modality studies. Overall, our study demonstrates the crucial need for quantitative description of complete single-cell anatomy in cell-type classification, as single-cell morphological diversity reveals a plethora of ways in which different cell types and their individual members may contribute to the configuration and function of their respective circuits

    Methylprednisolone as Adjunct to Endovascular Thrombectomy for Large-Vessel Occlusion Stroke

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    Importance It is uncertain whether intravenous methylprednisolone improves outcomes for patients with acute ischemic stroke due to large-vessel occlusion (LVO) undergoing endovascular thrombectomy. Objective To assess the efficacy and adverse events of adjunctive intravenous low-dose methylprednisolone to endovascular thrombectomy for acute ischemic stroke secondary to LVO. Design, Setting, and Participants This investigator-initiated, randomized, double-blind, placebo-controlled trial was implemented at 82 hospitals in China, enrolling 1680 patients with stroke and proximal intracranial LVO presenting within 24 hours of time last known to be well. Recruitment took place between February 9, 2022, and June 30, 2023, with a final follow-up on September 30, 2023.InterventionsEligible patients were randomly assigned to intravenous methylprednisolone (n = 839) at 2 mg/kg/d or placebo (n = 841) for 3 days adjunctive to endovascular thrombectomy. Main Outcomes and Measures The primary efficacy outcome was disability level at 90 days as measured by the overall distribution of the modified Rankin Scale scores (range, 0 [no symptoms] to 6 [death]). The primary safety outcomes included mortality at 90 days and the incidence of symptomatic intracranial hemorrhage within 48 hours. Results Among 1680 patients randomized (median age, 69 years; 727 female [43.3%]), 1673 (99.6%) completed the trial. The median 90-day modified Rankin Scale score was 3 (IQR, 1-5) in the methylprednisolone group vs 3 (IQR, 1-6) in the placebo group (adjusted generalized odds ratio for a lower level of disability, 1.10 [95% CI, 0.96-1.25]; P = .17). In the methylprednisolone group, there was a lower mortality rate (23.2% vs 28.5%; adjusted risk ratio, 0.84 [95% CI, 0.71-0.98]; P = .03) and a lower rate of symptomatic intracranial hemorrhage (8.6% vs 11.7%; adjusted risk ratio, 0.74 [95% CI, 0.55-0.99]; P = .04) compared with placebo. Conclusions and Relevance Among patients with acute ischemic stroke due to LVO undergoing endovascular thrombectomy, adjunctive methylprednisolone added to endovascular thrombectomy did not significantly improve the degree of overall disability.Trial RegistrationChiCTR.org.cn Identifier: ChiCTR210005172
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