95 research outputs found

    Anglo-Dutch, Split-Award Spectrum Auctions with a Downstream Market

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    Treating spectrum of different bandwidths as essentially distinct inputs needed for possibly different types of services has formed the core of spectrum analysis in academic research so far. New technological advances, such as cognitive radio, now allow us to move away from this inflexibility and to open up the new possibility of making different spectrum bands compatible. Spectrum, it is envisaged, is to become divisible and homogeneous. Auctions for this case have not been previously analyzed. By suitably adapting the Anglo-Dutch spectrum auction of Binmore and Klemperer (2000) and the split-award procurement auction of Anton and Yao (1989) and combining the adapted versions, we set out an ‘Anglo-Dutch split-award auction’ for divisible and homogeneous radio spectrum. An important feature of the game is a post-auction stage where the firms who have acquired some spectrum compete in the production of radio services. The equilibrium of the complete information game is completely characterized and important differences with the procurement auction highlighted. Finally, we compare the performance of our auction mechanism with a complete information form of the Binmore – Klemperer mechanism.radio spectrum, spectrum trading, imperfect competition

    A note on: jury size and the free rider problem

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    This note reassesses the basic result in Mukhopadhaya (2003) that, when jurors may acquire costly signals about a defendant's guilt, with a larger jury size the probability of reaching a correct verdict may in fact fall, contrary to the Condorcet Jury Theorem. We show that if the jurors coordinate on any one of a number of (equally plausible) asymmetric equilibria other than the symmetric equilibrium considered by Mukhopadhaya, the probability of accuracy reaches a maximum for a particular jury size and remains unchanged with larger juries, thus mitigating Mukhopadhaya''s result somewhat. However, the case for limiting the jury size – a recommendation by Mukhopadhaya – gains additional grounds if one shifts the focus from maximizing the probability of reaching a correct verdict to the maximization of the overall social surplus, measured by the expected benefits of jury decisions less the expected costs of acquiring signals.

    A Note on: Jury Size and the Free Rider Problem

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    This note reassesses the basic result in Mukhopadhaya (2003) that, when jurors may acquire costly signals about a defendant’s guilt, with a larger jury size the probability of reaching a correct verdict may in fact fall, contrary to the Condorcet Jury Theorem. We show that if the jurors coordinate on any one of a number of (equally plausible) asymmetric equilibria other than the symmetric equilibrium considered by Mukhopadhaya, the probability of accuracy reaches a maximum for a particular jury size and remains unchanged with larger juries, thus mitigating Mukhopadhaya’s result somewhat. However, the case for limiting the jury size a recommendation by Mukhoapdhaya gains additional grounds if one shifts the focus from maximizing the probability of reaching a correct verdict to the maximization of the overall social surplus, measured by the expected benefits of jury decisions less the expected costs of acquiring signals.jury size, free rider problem, Condorcet Jury Theorem

    Joint NASA Ames/Langley Experimental Evaluation of Integrated Air/Ground Operations for En Route Free Maneuvering

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    In order to meet the anticipated future demand for air travel, the National Aeronautics and Space Administration (NASA) is investigating a new concept of operations known as Distributed Air-Ground Traffic Management (DAG-TM). Under the En Route Free Maneuvering component of DAG-TM, appropriately equipped autonomous aircraft self separate from other autonomous aircraft and from managed aircraft that continue to fly under today s Instrument Flight Rules (IFR). Controllers provide separation services between IFR aircraft and assign traffic flow management constraints to all aircraft. To address concept feasibility issues pertaining to integrated air/ground operations at various traffic levels, NASA Ames and Langley Research Centers conducted a joint human-in-the-loop experiment. Professional airline pilots and air traffic controllers flew a total of 16 scenarios under four conditions: mixed autonomous/managed operations at three traffic levels and a baseline all-managed condition at the lowest traffic level. These scenarios included en route flights and descents to a terminal area meter fix in airspace modeled after the Dallas Ft. Worth area. Pilots of autonomous aircraft met controller assigned meter fix constraints with high success. Separation violations by subject pilots did not appear to vary with traffic level and were mainly attributable to software errors and procedural lapses. Controller workload was lower for mixed flight conditions, even at higher traffic levels. Pilot workload was deemed acceptable under all conditions. Controllers raised several safety concerns, most of which pertained to the occurrence of near-term conflicts between autonomous and managed aircraft. These issues are being addressed through better compatibility between air and ground systems and refinements to air and ground procedures

    Feasibility of Mixed Equipage Operations in the Same Airspace

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    This study used a human-in-the-loop simulation to examine the feasibility of mixed equipage operations in an automated separation assurance environment under higher traffic densities. The study involved two aircraft equipage alternatives with and without data link and four traffic conditions. In all traffic conditions the unequipped traffic count was increased linearly throughout the scenario from approximately 5 to 20 aircraft. Condition One consisted solely of this unequipped traffic, while the remaining three conditions also included a constant number of equipped aircraft operating within the same airspace: 15 equipped aircraft in condition two, 30 in condition three, and 45 in condition four. If traffic load became excessive during any run, participants were instructed to refuse sector entry to inbound unequipped aircraft until sector load became manageable. Results showed a progressively higher number of unequipped aircraft turned away under the second, third, and fourth scenario conditions. Controller workload also increased progressively. Participants rated the mixed operations concept as acceptable, with some qualifications about procedures and information displays. These results showed that mixed operations might be feasible in the same airspace, if unequipped aircraft count is held to a workable level. This level will decrease with increasing complexity. The results imply that integrated airspace configuration is feasible to a limit. The results also indicate that the conflict detection and resolution automation, equipage, and traffic density are important factors that will need to be considered for airspace configuration

    Impact of safety-related dose reductions or discontinuations on sustained virologic response in HCV-infected patients: Results from the GUARD-C Cohort

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    BACKGROUND: Despite the introduction of direct-acting antiviral agents for chronic hepatitis C virus (HCV) infection, peginterferon alfa/ribavirin remains relevant in many resource-constrained settings. The non-randomized GUARD-C cohort investigated baseline predictors of safety-related dose reductions or discontinuations (sr-RD) and their impact on sustained virologic response (SVR) in patients receiving peginterferon alfa/ribavirin in routine practice. METHODS: A total of 3181 HCV-mono-infected treatment-naive patients were assigned to 24 or 48 weeks of peginterferon alfa/ribavirin by their physician. Patients were categorized by time-to-first sr-RD (Week 4/12). Detailed analyses of the impact of sr-RD on SVR24 (HCV RNA <50 IU/mL) were conducted in 951 Caucasian, noncirrhotic genotype (G)1 patients assigned to peginterferon alfa-2a/ribavirin for 48 weeks. The probability of SVR24 was identified by a baseline scoring system (range: 0-9 points) on which scores of 5 to 9 and <5 represent high and low probability of SVR24, respectively. RESULTS: SVR24 rates were 46.1% (754/1634), 77.1% (279/362), 68.0% (514/756), and 51.3% (203/396), respectively, in G1, 2, 3, and 4 patients. Overall, 16.9% and 21.8% patients experienced 651 sr-RD for peginterferon alfa and ribavirin, respectively. Among Caucasian noncirrhotic G1 patients: female sex, lower body mass index, pre-existing cardiovascular/pulmonary disease, and low hematological indices were prognostic factors of sr-RD; SVR24 was lower in patients with 651 vs. no sr-RD by Week 4 (37.9% vs. 54.4%; P = 0.0046) and Week 12 (41.7% vs. 55.3%; P = 0.0016); sr-RD by Week 4/12 significantly reduced SVR24 in patients with scores <5 but not 655. CONCLUSIONS: In conclusion, sr-RD to peginterferon alfa-2a/ribavirin significantly impacts on SVR24 rates in treatment-naive G1 noncirrhotic Caucasian patients. Baseline characteristics can help select patients with a high probability of SVR24 and a low probability of sr-RD with peginterferon alfa-2a/ribavirin

    Meta-analysis of genome-wide association data and large-scale replication identifies additional susceptibility loci for type 2 diabetes

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    Genome-wide association (GWA) studies have identified multiple new genomic loci at which common variants modestly but reproducibly influence risk of type 2 diabetes (T2D)1-11. Established associations to common and rare variants explain only a small proportion of the heritability of T2D. As previously published analyses had limited power to discover loci at which common alleles have modest effects, we performed meta-analysis of three T2D GWA scans encompassing 10,128 individuals of European-descent and ~2.2 million SNPs (directly genotyped and imputed). Replication testing was performed in an independent sample with an effective sample size of up to 53,975. At least six new loci with robust evidence for association were detected, including the JAZF1 (p=5.0×10−14), CDC123/CAMK1D (p=1.2×10−10), TSPAN8/LGR5 (p=1.1×10−9), THADA (p=1.1×10−9), ADAMTS9 (p=1.2×10−8), and NOTCH2 (p=4.1×10−8) gene regions. The large number of loci with relatively small effects indicates the value of large discovery and follow-up samples in identifying additional clues about the inherited basis of T2D

    Sulfur-nitrogen bonded metal chelates. Part 17. Reactions of alcohols with the co-ordinated nitrile in nickel(II) complexes [NiL(NCR)][ClO<SUB>4</SUB>](L = a S,N,N-tridentate anion; R = Me, Et, or Ph) under different conditions

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    The reactions of the nitrile complexes [NiL(NCR)][ClO4]{HL1= methyl 2-[(2'-aminoethyl)amino]-cyclopent-1-enedithiocarboxylate, HL2= methyl 2-[(2'-dimethylaminoethyl)amino]cyclopent-1-enedithiocarboxylate, HL3= methyl 2-[(2'-diethylaminoethyl)amino]cyclopent-1-enedithio-carboxylate; R = Me, Et, or Ph} with methanol and ethanol under different experimental conditions have been investigated. Rate constants for these reactions have been measured spectrophotometric ally at 25 °C. Dry methanol reacts with the nitrile complexes, in absence of free nitrile, to produce dinuclear ”-methoxo complexes [Ni2L2(”-OMe)][ClO4] and the same reaction with wet methanol gives [Ni2L2(”-OH)][ClO4]. Both methoxo- and hydroxo-bridged compounds react with imidazole to form ”-imidazolato dinuclear complexes. All the complexes have been isolated and characterized. Dry methanol adds to the co-ordinated nitrile in complexes [NiL(NCR)][ClO4] in the presence of excess of free RCN, to produce imino-ether complexes [NiL{NH═C(OMe)R}][ClO4]. The rate data show the following decreasing order of reactivity of the nitrile complexes: [NiL1(NCMe)]+ &gt; [NiL1(NCEt)]+ &gt; [NiL2(NCMe)]+ &gt; [NiL3(NCMe)]+. The reaction rate with ethanol is much slower than that with methanol. The rates of formation of imino-ether complexes increase by more than four orders of magnitude when sodium alkoxide is used as a catalyst
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