3,853 research outputs found

    Stable phase retrieval with low-redundancy frames

    Full text link
    We investigate the recovery of vectors from magnitudes of frame coefficients when the frames have a low redundancy, meaning a small number of frame vectors compared to the dimension of the Hilbert space. We first show that for vectors in d dimensions, 4d-4 suitably chosen frame vectors are sufficient to uniquely determine each signal, up to an overall unimodular constant, from the magnitudes of its frame coefficients. Then we discuss the effect of noise and show that 8d-4 frame vectors provide a stable recovery if part of the frame coefficients is bounded away from zero. In this regime, perturbing the magnitudes of the frame coefficients by noise that is sufficiently small results in a recovery error that is at most proportional to the noise level.Comment: 12 pages AMSLaTeX, 1 figur

    Stock assessment in brown shrimp (Crangon crangon) part 1: Investigation of possible methods

    Get PDF
    Het Ministerie van LNV, de gezamenlijke Producentenorganisaties voor de garnalenvisserij in Nederland, en de natuurorganisaties Stichting de Noordzee en de Waddenvereniging hebben het belang onderschreven van een gezamenlijk traject naar een verduurzaming van de garnalenvisserij en het verkrijgen van een MSC (Marine Stewardship Councel) certificering voor de garnalenvisserij. Om voor een MSC label in aanmerking te komen moet er aangetoond worden dat de gewone garnaal, Crangon crangon, niet overbevist wordt. Momenteel wordt de garnalen visserij niet beheerd en is er geen officiële bestandschatting. Wel worden er door de ICES crangon werkgroep (WGCRAN, ICES working Group on crangon fisheries and life history) op een beschrijvende manier de fluctuaties in dichtheden van de gewone garnaal bijgehouden. Het is echter wenselijk om tot een meer kwantitatieve bestandschatting te komen

    Maternal Interaction Style in Affective Disordered, Physically Ill, and Normal Women

    Full text link
    Affective style (AS) and communication deviance (CD) have been suggested as markers of dysfunctional family environments that may be associated with psychiatric illness. Studies have focused mainly on parental responses during family interactions when an offspring is the identified patient. The present study is unique in examining AS and CD in mothers with unipolar depression, bipolar disorder, or chronic physical illness, and in normal controls. The sample consisted of 64 mothers with children ages 8 to 16. Unipolar mothers were more likely to show negative AS than were any other maternal group. There were no group differences for CD. Chronic stress, few positive life events, and single parenting were associated with AS. CD was associated solely with lower socioeconomic status. Results suggest that dysfunctional interactions are determined not only by maternal psychopathology, but also by an array of contextual factors that are related to the quality of the family environment

    A failure recovery planning prototype for Space Station Freedom

    Get PDF
    NASA is investigating the use of advanced automation to enhance crew productivity for Space Station Freedom in numerous areas, including failure management. A prototype is described that uses various advanced automation techniques to generate courses of action whose intents are to recover from a diagnosed failure, and to do so within the constraints levied by the failure and by Freedom's configuration and operating conditions

    Communication Styles of Children of Mothers with Affective Disorders, Chronic Medical Illness, and Normal Controls: A Contextual Perspective

    Full text link
    Research has demonstrated impaired parent-child relationships in families with affective disorders. The present study examines the association of children\u27s interactional style during a direct conflict-solving task to both the mother\u27s interactional style and the child\u27s diagnostic status. The sample includes 63 children, ages 8 to 16, of mothers with affective disorders, chronic medical illness, and normal controls. Children\u27s dominant coping style profile (CS) (autonomous, neutral, or critical) was related to their mother\u27s affective style (AS) (benign or negative). Affective disorder in the child at 6-month followup was associated with a critical CS profile at intake, while the child\u27s nonaffective symptomatology was unrelated to CS. Findings indicate that children\u27s affective disturbance is linked to interpersonal deficits in affectively charged situations. Results suggest that the child\u27s CS is more strongly predicted by maternal AS than by either the child\u27s or the mother\u27s diagnostic status

    Longitudinal Study of Diagnoses in Children of Women With Unipolar and Bipolar Affective Disorder

    Full text link
    School-age children of unipolar depressed, bipolar, chronically medically ill, or normal women were diagnosed every 6 months for up to 3 years. Offspring of unipolar women had the highest rates of disorder at all evaluations, but children of bipolar and medically ill mothers also experienced significant rates of disorder. Observing diagnoses from both past lifetime and prospective follow-up assessments, it appeared that most children who had diagnoses had onsets in preadolescence and continued a chronic or intermittent course of disorder. Thus, risk to offspring of ill mothers is not transitory and indicates a pernicious course that commonly includes affective disorders alone or in combination with behavior and anxiety disorders

    Case Study Sanwich Terns - a probabilistic analysis of the ecological effects of dreding

    Get PDF
    Every year, large amounts of sand are extracted from the North Sea to meet the demands for construction activities. Potential ecological effects of these sand mining activities have to be examined and reported in so called Environmental Impact Assessments (EIA’s). In the Netherlands, the potential impacts of sand mining activities on tern populations often form an important topic in these EIA’s. Sand mining causes an increase in silt concentrations. This increase will influence the turbidity of the water, which may affect populations of visual hunting birds, such as terns

    Depression in women: The family context and risk for recurrence

    Get PDF
    Is there something about the lives of depressed women that contribute to a vicious cycle of stress and depression? Examination of the interpersonal lives of depressed women reveals several characteristics that portend recurrent depression and intergenerational transmission of depression. From a large community sample of families in which the mothers had varying histories of depressive disorders (or no depression), 4 sources of stress are illustrated: marriage to men with psychopathology, children with disorders and impaired functioning, marital distress and relatively problematic relationships with children, and high levels of stressful life events to which these sources have contributed. These stressful circumstances were then shown to predict current depressive episodes (recurrence) and symptomatology. Women appear to select themselves into highly stressful environments that contribute to a cycle of stress and depression, and require treatments that target these circumstances and interpersonal vulnerabilities

    Data availability for the evaluation of stock status of species without catch advice: Case study: turbot (Psetta maxima) and Brill (Scophthalmus rhombus)

    Get PDF
    Several commercially important demersal fish stocks for the North Sea fisheries are classified as “category 11” in the light of the EU policy paper on fisheries management (17 May 2010, COM(2010) 241). For stocks in this category, there is no STECF (Scientific, technical and economic committee for fisheries ) management advice, due to the unknown status of the stocks. The reason for this is that the data and information available to perform analytical stock assessments are highly uncertain or lacking. This document describes existing data and options for collecting new data for the evaluation of the state of category 11 stocks. We focus on turbot and brill in the North Sea. Existing data from logbooks and the market sampling program can be used to estimate LPUE series used in age-based stock assessment methods, similar to other commercially important flatfish species such as plaice and sole. Landings Per Unit of Effort (LPUE) data of the Dutch beam trawl fleet > 221 kW were standardised for engine power and corrected for targeting behaviour as described below and graphically shown in Figure 3.2.1. The methods are similar to those used to analyse commercial LPUE data for North Sea plaice, described in Quirijns and Poos (2010). Landing rates (LPUE) by market category were calculated for the period 2002-2010. The corrected LPUE series indicate an increase in commercial LPUE for both species during the period 2002-2006. For turbot, the LPUE stays stable in the first five years, increases between 2006 and 2008, and decreases afterwards. The increase in brill LPUE is larger, and occurs throughout the study period. Compared to other commercially important flatfish species relatively few brill and turbot market samples are taken. This reduces the ability to track the cohorts in the LPUE series of the older ages which is a prerequisite for reliable stock assessment estimates. Also, the time series currently spans only 9 years. Collection of additional data may therefore be desirable. Expanding the BTS survey will provide industry independent data and would therefore give easily interpretable results. The option of an industry survey is also a good option if the survey is already being executed for sole and plaice. However, both options are costly. Therefore, the option of increasing the samples of turbot and brill at the auction is relatively easy and relatively inexpensive and therefore at present the most promising. The methods used for this document will not per definition be applicable for all category 11 species. For dab, flounder, lemon sole and tub gurnard, samples at the auctions are taken to collect biological data. For these species it may be possible to raise the data in a similar way as was done in this report to estimate the age composition of the stock. For other species (witch flounder, horse mackerel, silver smelt, red mullet and squid) there is no market sampling. For these species, other methods will have to be developed

    Process and information integration via hypermedia

    Get PDF
    Success stories for advanced automation prototypes abound in the literature but the deployments of practical large systems are few in number. There are several factors that militate against the maturation of such prototypes into products. Here, the integration of advanced automation software into large systems is discussed. Advanced automation systems tend to be specific applications that need to be integrated and aggregated into larger systems. Systems integration can be achieved by providing expert user-developers with verified tools to efficiently create small systems that interface to large systems through standard interfaces. The use of hypermedia as such a tool in the context of the ground control centers that support Shuttle and space station operations is explored. Hypermedia can be an integrating platform for data, conventional software, and advanced automation software, enabling data integration through the display of diverse types of information and through the creation of associative links between chunks of information. Further, hypermedia enables process integration through graphical invoking of system functions. Through analysis and examples, researchers illustrate how diverse information and processing paradigms can be integrated into a single software platform
    • …
    corecore