3,127 research outputs found

    Trading Inefficiencies in California's Electricity Markets

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    We study price convergence between the two major markets for wholesale electricity in California from their deregulation in April 1998 through November 2000, nearly the end of trading in one market. We would expect profit-maximizing traders to have eliminated persistent price differences between the markets. Institutional impediments and traders' incomplete understanding of the markets, however, could have delayed or prevented price convergence. We find that the two benchmark electricity prices in California -- the Power Exchange's day-ahead price and the Independent System Operator's real-time price -- differed substantially after the markets opened but then appeared to be converging by the beginning of 2000. Starting in May 2000, however, price levels and price differences increased dramatically. We consider several explanations for the significant price differences and conclude that rapidly changing market rules and market fundamentals, including one buyer's attempt to exercise a form of monopsony power, made it difficult for traders to take advantage of opportunities that ex post appear to have been profitable.

    The Changing Accountability Climate and Resulting Demands for Improved Fiduciary Capacity Affecting the World of Public Charities

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    In the wake of the scandals at major corporations such as Enron and WorldCom, attorneys general of several states are proposing additional legislative reforms to ensure financial accountability of nonprofit organizations, and both the Senate Finance Committee and House Ways and Means Committee have recently held hearings on proposed reforms for exempt organizations. These increasing demands for accountability have, in turn, amplified the pressure on boards of directors of all nonprofit organizations to govern effectively. But what is effective governance in this new climate of accountability, particularly for organizations holding exalted status under I.R.C. § 501(c)(3) and concomitant “public charity” status under 509(a)? This article will review current developments in the area of fiduciary duty of boards of directors of nonprofit tax-exempt organizations, to suggest what current trends indicate may be enhanced definitions of directors’ fiduciary duties in the post-Enron environment

    Inefficiencies and market power in financial arbitrage: a study of California's electricity markets

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    As with other commodities, electricity is often traded on both forward and spot markets. This was initially true in the restructured California electricity ndustry from 1998 to 2000. Though the power traded in the forward and spot markets was for delivery at the same times and locations, prices often differed in significant and predictable ways. We consider several explanations for this apparent inefficiency, concluding that uncertainty about regulatory penalties for trading in the spot market caused most firms to avoid trading on inter-market price differences. The few firms that did carry out these trades did not find it profit-maximizing to eliminate the price differences. Skyrocketing prices in the summer of 2000, however, changed the major buyers’ (utilities’) incentives and increased the price differentials between the markets

    Patching laser-reduced graphene oxide with carbon nanodots

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    Three-dimensional graphenes are versatile materials for a range of electronic applications and considered among the most promising candidates for electrodes in future electric double layer capacitors (EDLCs) as they are expected to outperform commercially used activated carbon. Parameters such as electrical conductivity and active surface area are critical to the final device performance. By adding carbon nanodots to graphene oxide in the starting material for our standard laser-assisted reduction process, the structural integrity (i.e. lower defect density) of the final 3D-graphene is improved. As a result, the active surface area in the hybrid starting materials was increased by 130% and the electrical conductivity enhanced by nearly an order of magnitude compared to pure laser-reduced graphene oxide. These improved material parameters lead to enhanced device performance of the EDLC electrodes. The frequency response, i.e. the minimum phase angle and the relaxation time, were significantly improved from −82.2° and 128 ms to −84.3° and 7.6 ms, respectively. For the same devices the specific gravimetric device capacitance was increased from 110 to a maximum value of 214 F g−1 at a scan rate of 10 mV s−1

    Estimation and prediction of the vehicle's motion basedon visual odometry and Kalman filter

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    Proceeding of: 14th International Conference, ACIVS 2012, Brno, Czech Republic, September 4-7, 2012The movement of the vehicle is an useful information for different applications, such as driver assistant systems or autonomous vehicles. This information can be known by different methods, for instance, by using a GPS or by means of the visual odometry. However, there are some situations where both methods do not work correctly. For example, there are areas in urban environments where the signal of the GPS is not available, as tunnels or streets with high buildings. On the other hand, the algorithms of computer vision are affected by outdoor environments, and the main source of difficulties is the variation in the ligthing conditions. A method to estimate and predict the movement of the vehicle based on visual odometry and Kalman filter is explained in this paper. The Kalman filter allows both filtering and prediction of vehicle motion, using the results from the visual odometry estimation.This work was also supported by Spanish Government through the CICYT projects FEDORA (Grant TRA2010-20255-C03-01), Driver Distraction Detector System (Grant TRA2011-29454-C03-02) and by CAM through the projects SEGVAUTO-II.Publicad

    Introducing EMMIE: An evidence rating scale to encourage mixed-method crime prevention synthesis reviews

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    Objectives This short report describes the need for, and the development of, a coding system to distil the quality and coverage of systematic reviews of the evidence relating to crime prevention interventions. The starting point for the coding system concerns the evidence needs of policymakers and practitioners. Methods The coding scheme (EMMIE) proposed builds on previous scales that have been developed to assess the probity, coverage and utility of evidence both in health and criminal justice. It also draws on the principles of realist synthesis and review. Results The proposed EMMIE scale identifies five dimensions to which systematic reviews intended to inform crime prevention should speak. These are the Effect of intervention, the identification of the causal Mechanism(s) through which interventions are intended to work, the factors that Moderate their impact, the articulation of practical Implementation issues, and the Economic costs of intervention

    Preliminary study of the reliability of imaging charge coupled devices

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    Imaging CCDs are capable of low light level response and high signal-to-noise ratios. In space applications they offer the user the ability to achieve extremely high resolution imaging with minimum circuitry in the photo sensor array. This work relates the CCD121H Fairchild device to the fundamentals of CCDs and the representative technologies. Several failure modes are described, construction is analyzed and test results are reported. In addition, the relationship of the device reliability to packaging principles is analyzed and test data presented. Finally, a test program is defined for more general reliability evaluation of CCDs
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