97 research outputs found

    The Role of CPS Nonresponse on the Level and Trend in Poverty

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    The Current Population Survey Annual Social and Economic Supplement (ASEC) serves as the data source for official income, poverty, and inequality statistics in the United States. There is a concern that the rise in nonresponse to earnings questions could deteriorate data quality and distort estimates of these important metrics. We use a dataset of internal ASEC records matched to Social Security Detailed Earnings Records (DER) to study the impact of earnings nonresponse on estimates of poverty from 1997-2008. Our analysis does not treat the administrative data as the “truth”; instead, we rely on information from both administrative and survey data. We compare a “full response” poverty rate that assumes all ASEC respondents provided earnings data to the official poverty rate to gauge the nonresponse bias. On average, we find the nonresponse bias is about 1.0 percentage point

    An Overview of Quasi-Monte Carlo Methods in Control Systems

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    Many control problems are so complex that analytic techniques fail to solve them [2]. Furthermore, even when analytic solutions are available, they may be computationally costly [2] and generally result in very high-order compensators [3]. Due to these reasons, we tend to accept approximate answers which provide us with certain performance guarantees for such problems. Sampling methods thus come into the picture to try and remedy the “cost of solution” problem by drawing samples from an appropriate space, and providing an approximate answer. For many years, random sampling has dominated the afore mentioned arena [8, 11, 4]. Random sample generation, with a uniform underlying distribution, however tends to cluster the samples on the boundary of the sample space in higher dimensions. It is for this reason that we are interested in presenting a method that distributes the points regularly in the sample space while providing deterministic guarantees on the error involved. Recently, deterministic or quasi-Monte Carlo (QMC) methods have proven superior to random methods in several applications such as the calculation of certain integrals [6], financial derivatives [7] and motion planning in robotics [10]. They have also been used for stability analysis of high speed networks [9]. In this work, we provide an overview of such deterministic quasi-Monte Carlo method of sampling, and their applications to control systems analysis and design. We present the basic concepts pertaining to quasi-Monte Carlo deterministic sampling. Such concepts include the following: Indicator functions, performance objective, generation of point sets, total variation, and error bounds

    Trouble in the Tails? What We Know about Earnings Nonresponse 30 Years after Lillard, Smith, and Welch

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    Earnings nonresponse in household surveys is widespread, yet there is limited knowledge of how nonresponse biases earnings measures. We examine the consequences of nonresponse on earnings gaps and inequality using Current Population Survey individual records linked to administrative earnings data. The common assumption that earnings are missing at random is rejected. Nonresponse across the earnings distribution is U-shaped, highest in the left and right tails. Inequality measures differ between household and administrative data due in part to nonresponse. Nonresponse biases earnings differentials by race, gender, and education, particularly in the tails. Flexible copula-based models can account for nonrandom nonresponse

    Trouble in the Tails? What We Know about Earnings Nonresponse Thirty Years after Lillard, Smith, and Welch

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    Earnings nonresponse in household surveys is widespread, yet there is limited evidence on whether and how nonresponse bias affects measured earnings. This paper examines the patterns and consequences of nonresponse using internal Current Population Survey individual records linked to administrative Social Security Administrative data on earnings for calendar years 2005-2010. Our findings confirm the conjecture by Lillard, Smith, and Welch (1986) that nonresponse across the earnings distribution is U-shaped. Left-tail “strugglers” and right-tail “stars” are least likely to report earnings. Household surveys understate earnings dispersion, reporting too few low and too few extremely high earners. Throughout much of the earnings distribution nonresponse is ignorable, but there exists trouble in the tails

    AllenRV: an Extensible Monitor for Multiple Complex Specifications with High Reactivity

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    International audienceAllenRV is a tool for monitoring temporal specifications, designed for ensuring good scalability in terms of size and number of formulae, and high reactivity. Its features reflect this design goal. For ensuring scalability in the number of formulae, it can simultaneously monitor a set of formulae written in past and future, next-free LTL, with some metric extensions; their efficient simultaneous monitoring is supported by a let construct allowing to share computations between formulae. For ensuring scalability in the size of formulae, it allows defining new abstractions as user-defined operators, which take discrete time boolean signals as arguments, but also constant parameters such as delays. For ensuring high reactivity, its monitoring algorithm does not require clock tick events, unlike many other tools. This is achieved by recomputing output signals both upon input signals changes and upon internally generated timeout events relative to such changes. As a consequence, monitoring remains efficient on arbitrarily fine-grained time domains. AllenRV is implemented by extending the existing Allen language and compiler, initially targeting ubiquitous applications using binary sensors, with temporal logic operators and a comprehensive library of user-defined operators on top of them. The most complex of these operators, including a complete adaptation of Allen-logic relations as selection operators, are proven correct with respect to their defined semantics. Thus, AllenRV offers an open platform for cooperatively developing increasingly complex libraries of high level, general or domain-specific, temporal operators and abstractions, without compromising correctness

    Re-branding Abu Dhabi: From oil giant to energy titan

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    This article presents a case study of Abu Dhabi\u27s \u27energy re-branding\u27 since 2005 when it declared its intention to transform itself from an oil exporter to a total energy giant that also embraces alternative (renewable and nuclear) energy. The first part of the article identifies the benefits of this policy for Abu Dhabi\u27s external diplomacy but argues that the real driver is the emirate\u27s domestic gas shortage and its effects on economic diversification and political legitimacy. The second part of the article discusses the motivations and interactions of local and foreign agents by focusing on the implementation of alternative energy platforms. It therefore provides a rare glimpse of the policy-making process in Abu Dhabi. The final part of the article examines the extent to which energy re-branding may be linked to a process by the government to reiterate, reinterpret and repudiate Emirati identity in order to enhance regime legitimacy in the twenty-first century. © 2012 Macmillan Publishers Ltd

    Analiza FPGA implementacije bilateralnih algoritama upravljanja za dodirnu teleoperaciju

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    This paper presents the FPGA implementation of sliding mode control algorithm for bilateral teleoperation, such that, the problem of haptic teleoperation is addressed. The presented study improves haptic fidelity by widening the control bandwidth. For wide control bandwidth, short control periods as well as short sampling periods are required that was achieved by the FPGA. The presented FPGA design methodology applies basic optimization methods in order to meet the required control period as well as the required hardware resource consumption. The circuit specification was performed by the high-level programing language LabVIEW using the fixed-point data type. Hence, short design times for producing the FPGA logic circuit can be achieved. The proposed FPGA-based bilateral teleoperation was validated by master-slave experimental device.Ovaj rad opisuje FPGA implementaciju algoritama upravljanja kliznim režimima za bilateralnu teleoperaciju, pri čemu je opisan problem haptičke teleoperacije. Prikazano istraživanje poboljšava dodirnu pouzdanost proširenjem upravljačkog propusnog pojasa. Za široki propusni pojas, potrebni su kratki upravljački periodi i brzo vrijeme uzorkovanja, što je postignuto primjenom FPGA sklopovlja. Prikazana metodologija za projektiranje FPGA sklopovlja koristi osnovne optimizacijske metode s ciljem postizanja potrebnih upravljačkih perioda i zahtijevane fizičke iskorištenosti sklopovlja. Specifikacije sklopovlja su provedene programskim jezikom visoke razine LabVIEW uz korištenje podataka s nepomičnim decimalnim zarezom. Stoga je moguće implementirati traženu logiku na FPGA sklopovlje u kratkom vremenu. Opisana bilateralna teleoperacija temeljena na FPGA slopovlju je testirana na eksperimentalnom postavu s nadre.enim i podre.enim čvorom
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