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Observable
Terms modified by Observable Selected AbstractsIndependence in Appearance and in Fact: An Experimental Investigation,CONTEMPORARY ACCOUNTING RESEARCH, Issue 1 2003Nicholas Dopuch Abstract In this study, we use experimental markets to assess the effect of the Security and Exchange Commission's (SEC's) new independence rule on investors' perceptions of independence, investors' payoff distributions, and market prices. The new rule requires client firms to disclose in their annual proxy statements the amount of nonaudit fees paid to their auditors. The new disclosure is intended to inform investors of auditors' incentives to compromise their independence. Our experimental design is a 2 3 between-subjects design, where we control the presence (unbiased reports) or absence of auditor independence in fact (biased reports). While independence in fact was not immediately observable to investors, we controlled for independence in appearance by varying the public disclosure of the extent of nonaudit services provided by the auditor to the client. In one market setting, investors were not given any information about whether the auditor provided such nonaudit services; in a second setting, investors were explicitly informed that the auditor did not provide any non-audit services; and in a third setting, investors were told that the auditor provided nonaudit services that could be perceived to have an adverse effect on independence in fact. We found that disclosures of nonaudit services reduced the accuracy of investors' beliefs of auditors' independence in fact when independence in appearance was inconsistent with independence in fact. This then caused prices of assets to deviate more from their economic predictions (lower market efficiency) in the inconsistent settings relative to the no-disclosure and consistent settings. Thus, disclosures of fees for nonaudit services could reduce the efficiency of capital markets if such disclosures result in investors forming inaccurate beliefs of auditor independence in fact - that is, auditors appear independent but they are not independent in fact, or vice versa. The latter is the maintained position of the American Institute of Certified Public Accountants (AICPA), which argued against the new rule. Further research is needed to assess the degree of correspondence between independence in fact and independence in appearance. [source] Centrioles are freed from cilia by severing prior to mitosis,CYTOSKELETON, Issue 7 2010Jeremy D.K. Parker Abstract Cilia are necessary for normal tissue development and homeostasis and are generally present during interphase, but not in mitosis. The precise mechanism of premitotic ciliary loss has been controversial, with data supporting either sequential disassembly through the transition zone or, alternatively, a severing event at the base of the cilia. Here we show by live cell imaging and immunofluoresence microscopy that resorbing flagella of Chlamydomonas leave remnants associated with the mother cell wall. We postulated that the remnants are the product of severing of doublet microtubules between the basal bodies and the flagellar transition zone, thereby freeing the centrioles to participate in spindle organization. We show via TEM that flagellar remnants are indeed flagellar transition zones encased in vesicles derived from the flagellar membrane. This transition zone vesicle can be lodged within the cell wall or it can be expelled into the environment. This process is observable in Chlamydomonas, first because the released flagellar remnants can remain associated with the cell by virtue of attachments to the cell wall, and second because the Chlamydomonas transition zone is particularly rich with electron-dense structure. However, release of basal bodies for spindle-associated function is likely to be conserved among the eukaryotes. © 2010 Wiley-Liss, Inc. [source] Compaction of cell shape occurs before decrease of elasticity in CHO-K1 cells treated with actin cytoskeleton disrupting drug cytochalasin DCYTOSKELETON, Issue 4 2009Christian Schulze Abstract The actin filaments of the cytoskeleton form a highly dynamic polymer scaffold which is actively involved in many essential mechanisms such as cell migration, transport, mitosis, and mechanosensitivity. We treated CHO-K1 cells with different concentrations of the actin cytoskeleton disrupting drug cytochalasin D. Then investigating the cells' elastic behaviour by scanning force microscopy-based rheology we confirmed for high cytochalasin D concentrations (,1.5 ,M) a significant decrease of mechanical stability. At lower concentrations we measured no significant softening, but flattening and a horizontal contraction was observable even at low concentrations (,0.3 ,M) of cytochalasin D. The observed changes in cell shape resulted in a lower cell volume, showing that there is compensation by volume for small decreases in cytoskeletal strength resulting from reduced numbers or lengths of actin filaments. These results suggest that the characteristic functions defining a cell's mechanical stability such as mechanosensitivity can be maintained via small changes in cell volume in order to counter fluctuations in cytoskeletal composition. Cell Motil. Cytoskeleton 2009. © 2009 Wiley-Liss, Inc. [source] Managing Interdependence: The Effects of Outsourcing Structure on the Performance of Complex Projects,DECISION SCIENCES, Issue 1 2008Pamsy P. Hui ABSTRACT The outsourcing of complex activities has become a common organizational practice. Yet very little research has focused on the implications of how these activities are divided up among outsourcing partners. Drawing on structural contingency theory, we argue that: (1) because activities within stages of complex projects are highly interdependent, outsourcing structures where owner firms do not maintain high levels of dominance over the activities that are performed will pose control and coordination challenges, leading to poor project performance; (2) the adverse effects of poorly structured outsourcing arrangements will spill over to subsequent project stages when activities are interdependent across project stages; and (3) dividing activities among large numbers of contractors or distributing work evenly among contractors exacerbates coordination and control problems further contributing to poor project performance. Our empirical analysis of 323 capital facility construction projects supports our predictions. Overall, these results provide strong evidence that some outsourcing structures are more costly than others and that because of the nature of complex projects the detrimental effects of poorly structured outsourcing are often not completely observable at the time activities are completed. We discuss the implications of our findings for capital construction and for outsourcing more generally. [source] Lithium response across generationsACTA PSYCHIATRICA SCANDINAVICA, Issue 5 2009P. Grof Objective:, To describe and integrate observations from bipolar patients responsive to lithium stabilization and their children. Method:, Selected findings are described from the clinical and biological investigations of adults meeting research criteria for bipolar disorder and for responsiveness to lithium stabilization; and from prospective studies of the children of lithium responders and non-responders. Results:, Response to prophylactic lithium identifies a valid subtype of bipolar disorder, however the search for biological markers of lithium response, while promising, has so far remained inconclusive. Adult responders to lithium stabilization exhibit definable clinical features which are also observable in their affected children. In prospective studies the children of bipolar parents develop symptoms earlier than reported previously, with marked differences between the offspring of lithium responders and non-responders. The illness evolves in predictable clinical stages, first from non-specific sleep and anxiety disorders to mood symptoms and then, often starting in adolescence, major depressive and later activated episodes. Conclusion:, Investigating and comparing unequivocal responders and non-responders to long-term lithium treatment and their offspring is a fertile research strategy for addressing a multitude of clinical and research questions. [source] Cross Section and Panel Data Estimators for Nonseparable Models with Endogenous RegressorsECONOMETRICA, Issue 4 2005Joseph G. Altonji We propose two new methods for estimating models with nonseparable errors and endogenous regressors. The first method estimates a local average response. One estimates the response of the conditional mean of the dependent variable to a change in the explanatory variable while conditioning on an external variable and then undoes the conditioning. The second method estimates the nonseparable function and the joint distribution of the observable and unobservable explanatory variables. An external variable is used to impose an equality restriction, at two points of support, on the conditional distribution of the unobservable random term given the regressor and the external variable. Our methods apply to cross sections, but our lead examples involve panel data cases in which the choice of the external variable is guided by the assumption that the distribution of the unobservable variables is exchangeable in the values of the endogenous variable for members of a group. [source] Income Variance Dynamics and HeterogeneityECONOMETRICA, Issue 1 2004Costas Meghir Recent theoretical work has shown the importance of measuring microeconomic uncertainty for models of both general and partial equilibrium under imperfect insurance. In this paper the assumption of i.i.d. income innovations used in previous empirical studies is removed and the focus of the analysis is placed on models for the conditional variance of income shocks, which is related to the measure of risk emphasized by the theory. We first discriminate amongst various models of earnings determination that separate income shocks into idiosyncratic transitory and permanent components. We allow for education- and time-specific differences in the stochastic process for earnings and for measurement error. The conditional variance of the income shocks is modelled as a parsimonious ARCH process with both observable and unobserved heterogeneity. The empirical analysis is conducted on data drawn from the 1967,1992 Panel Study of Income Dynamics. We find strong evidence of sizeable ARCH effects as well as evidence of unobserved heterogeneity in the variances. [source] Innovation and Peripherality: An Empirical Comparative Study of SMEs in Six European Union Member CountriesECONOMIC GEOGRAPHY, Issue 1 2008Andrew Copus Abstract This article examines the rates of innovative activity of small and medium-sized enterprises (SMEs) in central areas and equally developed but less accessible areas in six European Union member states. The probability of innovating is well predicted by the observable characteristics of firms, entrepreneurial characteristics, and business networks. More accessible areas consistently present higher rates of innovative activity than do their peripheral counterparts. The difference in the rates of peripheral and central areas is decomposed into observable and non-observable factors. The entire innovation gap is attributed to nonobservable factors that constitute a combination of behavior and environment. Innovation policy for SMEs should aim to meet businesses' specific needs (firm-specific factors) and to sustain and improve the innovative environment. [source] The Electrochemical Behavior of Nitrazepam at a Screen-Printed Carbon Electrode and Its Determination in Beverages by Adsorptive Stripping VoltammetryELECTROANALYSIS, Issue 19 2009Natasha Abstract The cyclic voltammetric behavior of nitrazepam was investigated at screen-printed carbon electrodes over the range ,1.5,V to +1.5,V. Two reduction peaks were observable on the negative scan, at ,0.7,V, and ,1.2,V using pH,6 buffer. On the return scan a single oxidation peak was obtained at ,0.05,V. For quantitative analysis of beverages, we developed an anodic adsorptive stripping voltammetric method which required only dilution with buffer. The identification of nitrazepam and flunitrazepam could be achieved using cyclic voltammetry. [source] Crystal structure of HLA-A*2402 complexed with a telomerase peptideEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 1 2006David Abstract HLA-A*2402 is the most commonly expressed HLA allele in oriental populations. It is also widely expressed in the Caucasian population, making it one of, if not the most abundant HLA,I types. In order to study its structure in terms of overall fold and peptide presentation, a soluble form of this HLA,I (,1, ,2, ,3 and ,2m domains) has been expressed, refolded and crystallized in complex with a cancer-related telomerase peptide (VYGFVRACL), and its structure has been solved to 2.8,Ĺ resolution. The overall structure of HLA-A*2402 is virtually identical to other reported peptide-HLA,I structures. However, there are distinct features observable from this structure at the HLA,I peptide binding pockets. The size and depth of pocket,B makes it highly suitable for binding to large aromatic side chains, which explains the high prevalence of tyrosine at peptide position,2. Also, for HLA binding at peptide position,5, there is an additional anchor point, which allows the proximal amino acids to protrude out, providing a prominent feature for TCR interaction. Finally, pocket,F allows the anchor residue at position,9 to be bound unusually deeply within the HLA structure. [source] Sex differences in the estimated intelligence of school childrenEUROPEAN JOURNAL OF PERSONALITY, Issue 3 2002Adrian Furnham This study investigated sex differences in estimated general and multiple intelligence in school children, their parents, and their teachers. There were three groups of participants: 285 (149 female, 136 male) pupils of a mixed government-run comprehensive school, between the ages of 13 and 16 years; 93 mothers and 58 fathers of the pupils; and five female and eight male teachers. Children estimated their own and their parents' IQ, whilst the parents estimated their own and their children's IQ; the teachers estimated only the children's intelligence. The aims of this study were firstly to assess whether perceptions of male intellectual superiority were observable in school age children and school teachers, and to make direct comparisons between the children's self-estimations and those of the parents and the teachers. Secondly, this study aimed to replicate previous literature on adult self-estimations of overall and multiple intelligences, and to compare these to estimations by children of these adults (their parents). Fewer sex differences were observed than expected. Teachers' estimations did not follow conceptions of male superiority. The patterns of sex differences in mother and teacher estimations of children were similar to each other, as were those of fathers and children. Verbal and numerical abilities were found to be most closely related to estimations of overall IQ in all three groups. Most striking was the lack of correlation between father and daughter estimations of each other. Reasons why this study failed to replicate findings on adult samples are discussed. Copyright © 2002 John Wiley & Sons, Ltd. [source] Optimal measurement placement for security constrained state estimation using hybrid genetic algorithm and simulated annealingEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 2 2009T. Kerdchuen Abstract This paper proposes a hybrid genetic algorithm and simulated annealing (HGS) for solving optimal measurement placement for power system state estimation. Even though the minimum number of measurement pairs is N considering the single measurement loss, their positions are required to make the system observable. HGS algorithm is a genetic algorithm (GA) using the acceptance criterion of simulated annealing (SA) for chromosome selection. The P, observable concept is used to check the network observability with and without single measurement pair loss contingency and single branch outage. Test results of 10-bus, IEEE 14, 30, 57, and 118-bus systems indicate that HGS is superior to tabu search (TS), GA, and SA in terms of higher frequency of the best hit and faster computational time. Copyright © 2007 John Wiley & Sons, Ltd. [source] INVESTIGATING EVOLUTIONARY TRADE-OFFS IN WILD POPULATIONS OF ATLANTIC SALMON (SALMO SALAR): INCORPORATING DETECTION PROBABILITIES AND INDIVIDUAL HETEROGENEITYEVOLUTION, Issue 9 2010Mathieu Buoro Evolutionary trade-offs among demographic parameters are important determinants of life-history evolution. Investigating such trade-offs under natural conditions has been limited by inappropriate analytical methods that fail to address the bias in demographic estimates that can result when issues of detection (uncertain detection of individual) are ignored. We propose a new statistical approach to quantify evolutionary trade-offs in wild populations. Our method is based on a state-space modeling framework that focuses on both the demographic process of interest as well as the observation process. As a case study, we used individual mark,recapture data for stream-dwelling Atlantic salmon juveniles in the Scorff River (Southern Brittany, France). In freshwater, juveniles face two life-history choices: migration to the ocean and sexual maturation (for males). Trade-offs may appear with these life-history choices and survival, because all are energy dependent. We found a cost of reproduction on survival for fish staying in freshwater and a survival advantage associated with the "decision" to migrate. Our modeling framework opens up promising prospects for the study of evolutionary trade-offs when some life-history traits are not, or only partially, observable. [source] Low-Threshold Distributed-Feedback Lasers Based on Pyrene-Cored Starburst Molecules with 1,3,6,8-Attached Oligo(9,9-Dialkylfluorene) ArmsADVANCED FUNCTIONAL MATERIALS, Issue 17 2009Ruidong Xia Abstract Here, a detailed characterization of the optical gain properties of sky-blue-light-emitting pyrene-cored 9,9-dialkylfluorene starbursts is reported; it is shown that these materials possess encouragingly low laser thresholds and relatively high thermal and environmental stability. The materials exhibit high solid-state photoluminescence (PL) quantum efficiencies (>90%) and near-single-exponential PL decay transients with excited state lifetimes of ,1.4,ns. The thin-film slab waveguide amplified spontaneous emission (ASE)-measured net gain reaches 75,78,cm,1. The ASE threshold energy is found to remain unaffected by heating at temperatures up to 130,°C, 40 to 50,°C above Tg. The ASE remained observable for annealing temperatures up to 170 or 200,°C. 1D distributed feedback lasers with 75% fill factor and 320,nm period show optical pumping thresholds down to 38,65,Wcm,2, laser slope efficiencies up to 3.9%, and wavelength tuning ranges of ,40,nm around 471,512,nm. In addition, these lasers have relatively long operational lifetimes, with N1/2,,,1.1,×,105,pulses for unencapsulated devices operated at ten times threshold in air. [source] Modelling and analysis of attenuation anisotropy in multi-azimuth VSP data from the Clair fieldGEOPHYSICAL PROSPECTING, Issue 5 2007Sonja Maultzsch ABSTRACT Anisotropic variations in attenuation are of interest since they can give information on the fracture system and may be more amenable to measurement than absolute attenuation values. We examine methods for detecting changes in relative attenuation with azimuth from VSP data, and validate the techniques on synthetic data. Analysis of a multi-azimuth walkaway VSP data set from a fractured hydrocarbon reservoir indicates that such azimuthal variations in P-wave attenuation are observable. The effects are localized in the reservoir, and analysis allows the prediction of a fracture strike direction, which agrees with geological information. The observed effects can be modelled under reasonable assumptions, which suggests the validity of the link between the anisotropic attenuation and the fracturing. [source] Does Work Always Pay in Germany?GERMAN ECONOMIC REVIEW, Issue 3 2010Christoph Scheicher Equity; redistribution; social insurance; taxes Abstract. Income redistribution in Germany is the result of a combination of several redistribution instruments: there is a complex income tax law, different obligatory social insurances and supplementary benefits. This paper estimates income redistribution by quantile regression, using German EVS data. Two results are obtained: income after redistribution does not always increase in line with income before redistribution, i.e. for people with a low income before redistribution, it does not make sense to increase their efforts, since more work means less earnings. Further, an increasing redistribution rate for higher incomes is not always observable from the data. [source] Maternal employment and overweight children: does timing matter?HEALTH ECONOMICS, Issue 8 2008Stephanie von Hinke Kessler Scholder Abstract Recent literature has shown consistent evidence of a positive relationship between maternal employment and children's overweight status. These studies largely use average weekly work hours over the child's life to measure employment. This paper specifically aims at exploring the importance of the timing of employment. Using various econometric techniques to control for observable and unobservable child and family characteristics, the results show that full-time maternal employment during mid-childhood positively affects the probability of being overweight at age 16. There is no evidence that part-time or full-time employment at earlier/later ages affects this probability. Copyright © 2008 John Wiley & Sons, Ltd. [source] Rhythmic hippocampal slow oscillation characterizes REM sleep in humansHIPPOCAMPUS, Issue 6 2001Róbert Bódizs Abstract Hippocampal rhythmic slow activity (RSA) is a well-known electrophysiological feature of exploratory behavior, spatial cognition, and rapid eye movement (REM) sleep in several mammalian species. Recently, RSA in humans during spatial navigation was reported, but systematic data regarding human REM sleep are lacking. Using mesio-temporal corticography with foramen ovale electrodes in epileptic patients, we report the presence of a 1.5,3-Hz synchronous rhythmic hippocampal oscillation seemingly specific to REM sleep. This oscillation is continuous during whole REM periods, is clearly observable by visual inspection, and appears in tonic and phasic REM sleep episodes equally. Quantitative analysis proved that this 1.5,3-Hz frequency band significantly differentiates REM sleep from waking and slow-wake sleep (SWS). No other frequency band proved to be significant or showed this high rhythmicity. Even in temporo-lateral surface recordings, although visually much less striking, the relative power of the 1.5,3-Hz frequency band differentiates REM sleep from other states with statistical significance. This could mean that the 1.5,3-Hz hippocampal RSA spreads over other cortical areas in humans as in other mammals. We suggest that this oscillation is the counterpart of the hippocampal theta of mammalian REM sleep, and that the 1.5,3-Hz delta EEG activity is a basic neurophysiological feature of human REM sleep. Hippocampus 2001;11:747,753. © 2001 Wiley-Liss, Inc. [source] Development of a historical ice database for the study of climate change in CanadaHYDROLOGICAL PROCESSES, Issue 18 2002Frédéric Lenormand Abstract The Canadian government has been compiling various observations on freshwater and coastal sea ice conditions for many years. However, the records are not easily accessible and are dispersed within different government departments. Given this, a major effort was undertaken in order to gather all available observations into a common database,the Canadian Ice Database (CID). This database will respond to the needs for climate monitoring in Canada, the validation and improvement of numerical ice models and the development of new remote-sensing methods. Indeed, several studies have shown that freshwater ice and sea ice are good proxy indicators of climate variability and change. The first version of CID contains in situ observations from 757 sites distributed across Canada, which were originally kept on digital or paper records at the Meteorological Service of Canada Headquarters and the Canadian Ice Service (CIS). The CID holds 63 546 records covering the period from ice season 1822,23 to 2000,01. An analysis of the database allows one to trace the temporal evolution of the ice networks. The freeze-up/break-up network of 2000,01 only represents 4% of what it was in 1985,86. A drastic decline of the ice thickness and the snow on ice network is also observable. In 1997,98, it represented only 10% of the network that existed in 1984,85. The major budget cuts in Canadian government agencies during the late 1980s and the 1990s offer the most plausible explanation for the drastic decline in the ice observation networks. Weekly ice coverage determination on large lakes from satellite imagery by the CIS and the national volunteer ice monitoring program, IceWatch, may provide a means of reviving, at least, the freeze-up/break-up network. Copyright © 2002 John Wiley & Sons, Ltd. [source] Germ-line transformation of the South American malaria vector, Anopheles albimanus, with a piggyBac/EGFP transposon vector is routine and highly efficientINSECT MOLECULAR BIOLOGY, Issue 4 2002O. P. Perera Abstract Stable and efficient germ-line transformation was achieved in the South American malaria vector, Anopheles albimanus, using a piggyBac vector marked with an enhanced green fluorescent protein gene regulated by the Drosophila melanogaster polyubiquitin promoter. Transgenic mosquitoes were identified from four independent experiments at frequencies ranging from 20 to 43% per fertile G0. Fluorescence was observable throughout the body of larvae and pupae, and abdominal segments of adults. Transgenic lines analysed by Southern hybridization had one to six germ-line integrations, with most lines having three or more integrations. Hybridized transposon vector fragments and insertion site sequences were consistent with precise piggyBac -mediated integrations, although this was not verified for all lines. The piggyBac/PUbnlsEGFP vector appears to be a robust transformation system for this anopheline species, in contrast to the use of a piggyBac vector in An. gambiae. Further tests are needed to determine if differences in anopheline transformation efficiency are due to the marker systems or to organismal or cellular factors specific to the species. [source] NONPARAMETRIC SURVEY RESPONSE ERRORS,INTERNATIONAL ECONOMIC REVIEW, Issue 4 2007Rosa L. Matzkin I present nonparametric methods to identify and estimate the biases associated with response errors. When applied to survey data, these methods can be used to analyze how observable and unobservable characteristics of the respondent, and characteristics of the design of the survey, affect errors in the responses. This provides a method to correct the biases that those errors generate, by using the estimated response errors to "undo" those biases. The results are useful also to design better surveys, since they point at characteristics of the design and of subpopulations of respondents that can provide identification of response errors. Several models are considered. [source] Sensor network design for fault tolerant estimationINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 1 2004M. Staroswiecki Abstract This paper addresses the problem of fault tolerant estimation and the design of fault tolerant sensor networks. Fault tolerance is defined with respect to a given estimation objective, namely a given functional of the system state should remain observable when sensor failures occur. Redundant and minimal sensor sets are defined and organized into an automaton which contains all the subsets of sensors such that the estimation objective can be achieved. Three criteria, which evaluate the system fault tolerance with respect to sensor failures when a reconfiguration strategy is used, are introduced: (strong and weak) redundancy degrees (RD), sensor network reliability (R), and mean time to non-observability (MTTNO). Sensor networks are designed by finding redundant sensor sets whose RD and/or R and/or MTTNO are larger than some specified values. A ship boiler example is developed for illustration. Copyright © 2004 John Wiley & Sons, Ltd. [source] An analysis of cloud observations from Vernadsky, AntarcticaINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 10 2010Amélie Kirchgäßner Abstract This paper presents results of a combined analysis of cloud observations made at the Antarctic base Faraday/Vernadsky between 1960 and 2005 and sea ice concentration from the HadISST1 data set. The annual total cloud cover has increased significantly during this period with the strongest and most significant positive trend found in winter, and positive tendencies observable in all seasons. This trend is associated with a decrease in sea ice concentration in the area of the Western Antarctic Peninsula. Though the observed sea ice reduction is actually larger and more significant in summer and autumn, there is actually a significant relation between total cloud cover and sea ice concentration only in winter. The increase in the total cloud cover is neither reflected in the low cloud amount nor in the number of records for low, medium or high level clouds. It is therefore thought that the increase in the total cloud cover is caused by an increase in the amount of medium and/or high level clouds. Instead, records for the low cloud amount show a redistribution from cases of extreme cloud cover (0, 1, 7 and 8 okta), which account for up to 90% of annual records, to cases of moderate cloud cover. In accordance with the decrease in sea ice, this may indicate a shift from low-level stratiform towards convective clouds. Copyright © 2009 Royal Meteorological Society [source] Characterizing user-perceived impairment events using end-to-end measurementsINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 10 2005Soshant Bali Abstract Measures of quality of service (QoS) must correlate to end-user experience. For multimedia services, these metrics should focus on the phenomena that are observable by the end-user. Metrics such as delay and loss may have little direct meaning to the end-user because knowledge of specific coding and/or adaptive techniques is required to translate delay and loss to the user-perceived performance. Impairment events, as defined in this paper, are observable by the end-users independent of coding, adaptive playout or packet loss concealment techniques employed by their multimedia applications. Time between impairments and duration of impairments are metrics that are easily understandable by a network user. Methods to detect these impairment events using end-to-end measurements are developed here. In addition, techniques to identify Layer 2 route changes and congestion events using end-to-end measurements are also developed. These are useful in determining what caused the impairments. End-to-end measurements were conducted for about 26 days on 9 different node pairs to evaluate the developed techniques. Impairments occurred at a high rate on the two paths on which congestion events were detected. On these two paths, congestion occurred for 6,8 hours during the day on weekdays. Impairments caused by route changes were rare but lasted for several minutes. Copyright © 2005 John Wiley & Sons, Ltd. [source] High-resolution images from compressed low-resolution video: Motion estimation and observable pixelsINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 2 2004L. D. Alvarez Abstract In this article, we address the problem of obtaining a high-resolution (HR) image from a compressed low-resolution (LR) video sequence. Motion information plays a critical role in solving this problem, and we determine which pixels in the sequence provide useful information for calculating the high-resolution image. The bit stream of hybrid motion compensated video compression methods includes low-resolution motion-compensated images; we therefore also study which pixels in these images should be used to increase the quality of the reconstructed image. Once the useful (observable) pixels in the low-resolution and motion-compensated sequences have been detected, we modify the acquisition model to only account for these observations. The proposed approach is tested on real compressed video sequences and the improved performance is reported. © 2004 Wiley Periodicals, Inc. Int J Imaging Syst Technol 14, 58,66, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20008 [source] The N -particle wave function as a homogeneous functional of the densityINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 14 2007Tamás Gál Abstract It is shown that requiring consistency with the structure of the equation that determines the wave function associated to a density ,() by density-functional theory, yields the N -particle wave function as a degree-half homogeneous functional of the density, and leads to a separation A[N, ,] of N dependence (with N = ,,() d) of density functionals A[,] = A[,,, ,] for which A[,,, ,,] = , A[,, ,]; as a consequence of the linearity of quantum mechanical operators. This implies that the ground-state value of any quantum mechanical observable arises naturally as a degree-one homogeneous N -particle density functional. This general scheme for the structure of density functionals can be considered as the conceptual generalization of the Weizsäcker functional, which is the exact degree-one homogeneous one-particle kinetic-energy density functional. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [source] A generalized homogeneous domination approach for global stabilization of inherently nonlinear systems via output feedbackINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 7 2007Jason Polendo Abstract In this paper, we introduce a generalized framework for global output feedback stabilization of a class of uncertain, inherently nonlinear systems of a particularly complex nature since their linearization around the equilibrium is not guaranteed to be either controllable or observable. Based on a new observer/controller construction and a homogeneous domination design, this framework not only unifies the existing output feedback stabilization results, but also leads to more general results which have been never achieved before, establishing this methodology as a universal tool for the global output feedback stabilization of inherently nonlinear systems. Copyright © 2006 John Wiley & Sons, Ltd. [source] On stabilization of nonlinear systems under data rate constraints using output measurementsINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 6 2006C. De Persis Abstract We present a contribution to the problem of semi-global asymptotic stabilization of nonlinear continuous-time systems under data rate constraints when only output measurements are available. We consider systems which are uniformly observable and we point out that the design of an ,embedded-observer' decoder and a controller which semi-globally stabilize this class of systems under data-rate constraints requires an appropriate choice of the observer gain and the data rate. Copyright © 2006 John Wiley & Sons, Ltd. [source] Design of exponential observers for nonlinear systems by embeddingINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 3 2004A. Rapaport Abstract For nonlinear systems in ,n which are observable but not uniformly, we study how to design explicitly exponential observers, after having the system immersed in ,m with m>n. The central issue concerns the determination of a lipschitzian extension in ,m of the dynamics, which is defined exclusively on a subset of empty interior. We propose some constructive tools and illustrate their utility on a biological example. Copyright © 2004 John Wiley & Sons, Ltd. [source] State, Corruption, and Criminalisation in ChinaINTERNATIONAL SOCIAL SCIENCE JOURNAL, Issue 169 2001Guilhem Fabre Given the decentralisation and opening-up that China has been experiencing since 1979, the rise of corruption and the criminal economy can be attributed to the increased opportunities observable at macro-economic level and a context of relative impunity for the most serious offences. Functionalist and culturalist interpretations of this corruption fail to take account of its political dimension, which is not simply a matter of its instrumentalisation in the struggle between ruling factions. Contrary to the situation prevailing in certain democratic developing countries, criminals in China do not have the option of becoming state representatives, but certain state representatives, notably at local level, are well placed to make choices to the advantage of criminal circles, as happens in Mexico, and so share in the illicit gains. 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