960 resultados para Four-color problem


Relevância:

30.00% 30.00%

Publicador:

Resumo:

IEEE Transactions on Knowledge and Data Engineering, vol. 15, no. 5, pp. 1338-1343, 2003.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Celem publikacji jest podjęcie próby przeanalizowania polityki, jaką Turcja prowadzi wobec obcokrajowców poszukujących schronienia na jej terytorium. O ważkości zagadnienia zadecydowała w ostatnich latach przede wszystkim tocząca się w Syrii wojna domowa, w wyniku której na terytorium Turcji znalazło się ponad 700 tysięcy Syryjczyków. Szczególne w tym kontekście kontrowersje budzi fakt stosowania przez Turcję podwójnych standardów w przedmiocie nadawania imigrantom konwencyjnego statusu uchodźcy. Państwo to, jako jedno z czterech na świecie, w momencie przystępowania do Konwencji dotyczącej statusu uchodźców i Protokołu nowojorskiego zastrzegło sobie prawo do stosowania w tej materii tzw. kryterium geograficznego. W efekcie, o ile status uchodźcy nadany być może osobom przybywającym zza zachodnich granic Turcji, o tyle uciekinierzy z państw takich, jak Syria, Iran, czy Irak z formalnego punktu widzenia są „poszukującymi schronienia” (tur. sığınmacı). To zaś oznacza brak ich konwencyjnej ochrony. Celem artykułu jest jednak nie tylko przeanalizowanie prawnego i rzeczywistego położenia, w jakim znajdują się ofiary syryjskiej wojny domowej, przybywające na terytorium Turcji, a także próba przewidzenia scenariusza rozwoju tejże sytuacji. Celem uczynienia analizy możliwie najbardziej rzetelną, odwołano się zarówno do anglo, jak i tureckojęzycznych materiałów źródłowych.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

A neural network model of 3-D visual perception and figure-ground separation by visual cortex is introduced. The theory provides a unified explanation of how a 2-D image may generate a 3-D percept; how figures pop-out from cluttered backgrounds; how spatially sparse disparity cues can generate continuous surface representations at different perceived depths; how representations of occluded regions can be completed and recognized without usually being seen; how occluded regions can sometimes be seen during percepts of transparency; how high spatial frequency parts of an image may appear closer than low spatial frequency parts; how sharp targets are detected better against a figure and blurred targets are detector better against a background; how low spatial frequency parts of an image may be fused while high spatial frequency parts are rivalrous; how sparse blue cones can generate vivid blue surface percepts; how 3-D neon color spreading, visual phantoms, and tissue contrast percepts are generated; how conjunctions of color-and-depth may rapidly pop-out during visual search. These explanations arise derived from an ecological analysis of how monocularly viewed parts of an image inherit the appropriate depth from contiguous binocularly viewed parts, as during DaVinci stereopsis. The model predicts the functional role and ordering of multiple interactions within and between the two parvocellular processing streams that join LGN to prestriate area V4. Interactions from cells representing larger scales and disparities to cells representing smaller scales and disparities are of particular importance.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The child is the most precious asset and the focal point of development for any country. However, unless children are brought up in a stimulating and conducive environment getting the best possible care and protection, their physical, mental, emotional and social development is susceptible to permanent damage. Ethiopia, being one of the least developed countries of the world due to interrelated and complex socio-economic factors including man-made and natural calamities, a large portion of our population - especially children - are victimized by social evils like famine, disease, poverty, mass displacement, lack of education and family instability. Owing to the fact that children are the most vulnerable group among the whole society and also because they constitute half of the population it is evident that a considerable number of Ethiopian children are living under difficult circumstances. Therefore, as in a number of other third world countries there are many poor, displaced, unaccompanied and orphaned children in our country. A considerable proportion of these children work on the street with some even totally living on the street without any adult care and protection. These children are forced to the streets in their tight for survival. They supplement their parents meagre income or support themselves with the small incomes they earn doing menial jobs. In doing this, street children face the danger of getting into accidents and violence, they get exploited and abused, many are forced to drop out of school or never get the chance to be enroled at all and some drift into begging or petty crime. This study is undertaken mainly for updating the findings of previous studies, monitoring changing trends, examining new facts of the problem and getting a better understanding of the phenomenon in the country by covering at least some of the major centres where the problem is acute. Thus, the outcome of this research can be useful in the formation of the social welfare programme of the country. Finally, in recognition of the urgency of the problem and the limited resources available, the Ministry of Labour and Social Affairs expresses appreciation to all agencies engaged in the rehabilitation of street children and prevention of the problem. The Ministry also calls for more co-operation and support between concerned governmental and non-governmental organizations in their efforts for improving the situation of street children and in curbing the overwhelming nature of the problem.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Deriving maps of phytoplankton taxa based on remote sensing data using bio-optical properties of phytoplankton alone is challenging. A more holistic approach was developed using artificial neural networks, incorporating ecological and geographical knowledge together with ocean color, bio-optical characteristics, and remotely sensed physical parameters. Results show that the combined remote sensing approach could discriminate four major phytoplankton functional types (diatoms, dinoflagellates, coccolithophores, and silicoflagellates) with an accuracy of more than 70%. Models indicate that the most important information for phytoplankton functional type discrimination is spatio-temporal information and sea surface temperature. This approach can supply data for large-scale maps of predicted phytoplankton functional types, and an example is shown.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Phytoplankton, at the base of the marine food web, represent a fundamental food source in coral reef ecosystems. The timing (phenology) and magnitude of the phytoplankton biomass are major determinants of trophic interactions. The Red Sea is one of the warmest and most saline basins in the world, characterized by an arid tropical climate regulated by the monsoon. These extreme conditions are particularly challenging for marine life. Phytoplankton phenological indices provide objective and quantitative metrics to characterize phytoplank- ton seasonality. The indices i.e. timings of initiation, peak, termination and duration are estimated here using 15 years (1997–2012) of remote sensing ocean-color data from the European Space Agency (ESA) Climate Change Initiative project (OC-CCI) in the entire Red Sea basin. The OC-CCI product, comprising merged and bias-corrected observations from three independent ocean-color sensors (SeaWiFS, MODIS and MERIS), and processed using the POLYMER algorithm (MERIS period), shows a significant increase in chlorophyll data cover- age, especially in the southern Red Sea during the months of summer NW monsoon. In open and reef-bound coastal waters, the performance of OC-CCI chlorophyll data is shown to be comparable with the performance of other standard chlorophyll products for the global oceans. These features have permitted us to investigate phytoplankton phenology in the entire Red Sea basin, and during both winter SE monsoon and summer NW monsoon periods. The phenological indices are estimated in the four open water provinces of the basin, and further examined at six coral reef complexes of particular socio-economic importance in the Red Sea, including Siyal Islands, Sharm El Sheikh, Al Wajh bank, Thuwal reefs, Al Lith reefs and Farasan Islands. Most of the open and deeper waters of the basin show an apparent higher chlorophyll concentration and longer duration of phyto- plankton growth during the winter period (relative to the summer phytoplankton growth period). In contrast, most of the reef-bound coastal waters display equal or higher peak chlorophyll concentrations and equal or lon- ger duration of phytoplankton growth during the summer period (relative to the winter phytoplankton growth period). The ecological and biological significance of the phytoplankton seasonal characteristics are discussed in context of ecosystem state assessment, and particularly to support further understanding of the structure and functioning of coral reef ecosystems in the Red Sea.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Heavy particle collisions, in particular low-energy ion-atom collisions, are amenable to semiclassical JWKB phase integral analysis in the complex plane of the internuclear separation. Analytic continuation in this plane requires due attention to the Stokes phenomenon which parametrizes the physical mechanisms of curve crossing, non-crossing, the hybrid Nikitin model, rotational coupling and predissociation. Complex transition points represent adiabatic degeneracies. In the case of two or more such points, the Stokes constants may only be completely determined by resort to the so-called comparison- equation method involving, in particular, parabolic cylinder functions or Whittaker functions and their strong-coupling asymptotics. In particular, the Nikitin model is a two transition-point one-double-pole problem in each half-plane corresponding to either ingoing or outgoing waves. When the four transition points are closely clustered, new techniques are required to determine Stokes constants. However, such investigations remain incomplete, A model problem is therefore solved exactly for scattering along a one-dimensional z-axis. The energy eigenvalue is b(2)-a(2) and the potential comprises -z(2)/2 (parabolic) and -a(2) + b(2)/2z(2) (centrifugal/centripetal) components. The square of the wavenumber has in the complex z-plane, four zeros each a transition point at z = +/-a +/- ib and has a double pole at z = 0. In cases (a) and (b), a and b are real and unitarity obtains. In case (a) the reflection and transition coefficients are parametrized by exponentials when a(2) + b(2) > 1/2. In case (b) they are parametrized by trigonometrics when a(2) + b(2) <1/2 and total reflection is achievable. In case (c) a and b are complex and in general unitarity is not achieved due to loss of flux to a continuum (O'Rourke and Crothers, 1992 Proc. R. Sec. 438 1). Nevertheless, case (c) coefficients reduce to (a) or (b) under appropriate limiting conditions. Setting z = ht, with h a real constant, an attempt is made to model a two-state collision problem modelled by a pair of coupled first-order impact parameter equations and an appropriate (T) over tilde-tau relation, where (T) over tilde is the Stueckelberg variable and tau is the reduced or scaled time. The attempt fails because (T) over tilde is an odd function of tau, which is unphysical in a real collision problem. However, it is pointed out that by applying the Kummer exponential model to each half-plane (O'Rourke and Crothers 1994 J. Phys. B: At. Mel. Opt. Phys. 27 2497) the current model is in effect extended to a collision problem with four transition points and a double pole in each half-plane. Moreover, the attempt in itself is not a complete failure since it is shown that the result is a perfect diabatic inelastic collision for a traceless Hamiltonian matrix, or at least when both diagonal elements are odd and the off-diagonal elements equal and even.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

ANPO (A Non-predefined Outcome) is an an art-making methodology that employs structuralist theory of language (Saussure, Lacan, Foucault) combined with Hegel’s dialectic and the theory of creation of space by Lefebvre to generate spaces of dialogue and conversation between community members and different stakeholders. These theories of language are used to find artistic ways of representing a topic that community members have previously chosen. The topic is approached in a way that allows a visual, aural, performative and gustative form. To achieve this, the methodology is split in four main steps: step 1 ‘This is not a chair’, Step 2 ‘The topic’, Step 3 ‘ Vis-á-vis-á-vis’ and step 4. ‘Dialectical representation’ where the defined topic is used to generate artistic representations.The step 1 is a warm up exercise informed by the Rene Magritte painting ‘This is not a Pipe’. This exercise aims to help the participants to see an object as something else than an object but as a consequence of social implications. Step 2, participants choose a random topic and vote for it. The artist/facilitator does not predetermine the topic, participants are the one who propose it and choose it. Step 3, will be analysed in this publication and finally step 4, the broken down topic is taken to be represented and analysed in different ways. 

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Recently, a single-symbol decodable transmit strategy based on preprocessing at the transmitter has been introduced to decouple the quasi-orthogonal space-time block codes (QOSTBC) with reduced complexity at the receiver [9]. Unfortunately, it does not achieve full diversity, thus suffering from significant performance loss. To tackle this problem, we propose a full diversity scheme with four transmit antennas in this letter. The proposed code is based on a class of restricted full-rank single-symbol decodable design (RFSDD) and has many similar characteristics as the coordinate interleaved orthogonal designs (CIODs), but with a lower peak-to-average ratio (PAR).

Relevância:

30.00% 30.00%

Publicador:

Resumo:

There has been an increasing focus on social and emotional development in educational programmes in early childhood as both variables are believed to influence behavioural outcomes in the classroom. However, relationships between social and emotional development and behaviour in early childhood have rarely been explored. This article sets out to investigate the conceptualisation of these variables and their inter-relationships. Structural equation models were used to assess if differences exist between boys and girls in relation to social and emotional competences, which could affect the relative success of such programmes. This article is based on cross-sectional data collected from 749 four- to six-year-olds and their teachers. The findings generally supported the hypothesised relationships between social and emotional development variables and prosocial behaviour (including internalising behaviour) for boys and girls. However, some gender differences were noted in externalising behaviour, which teachers often consider to be most significant due to its potentially disruptive nature in the classroom.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Although alcohol problems and alcohol consumption are related, consumption does not fully account for differences in vulnerability to alcohol problems. Therefore, other factors should account for these differences. Based on previous research, it was hypothesized that risky drinking behaviours, illicit and prescription drug use, affect and sex differences would account for differences in vulnerability to alcohol problems while statistically controlling for overall alcohol consumption. Four models were developed that were intended to test the predictive ability of these factors, three of which tested the predictor sets separately and a fourth which tested them in a combined model. In addition, two distinct criterion variables were regressed on the predictors. One was a measure of the frequency that participants experienced negative consequences that they attributed to their drinking and the other was a measure of the extent to which participants perceived themselves to be problem drinkers. Each of the models was tested on four samples from different populations, including fIrst year university students, university students in their graduating year, a clinical sample of people in treatment for addiction, and a community sample of young adults randomly selected from the general population. Overall, support was found for each of the models and each of the predictors in accounting for differences in vulnerability to alcohol problems. In particular, the frequency with which people become intoxicated, frequency of illicit drug use and high levels of negative affect were strong and consistent predictors of vulnerability to alcohol problems across samples and criterion variables. With the exception of the clinical sample, the combined models predicted vulnerability to negative consequences better than vulnerability to problem drinker status. Among the clinical and community samples the combined model predicted problem drinker status better than in the student samples.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Twenty-eight grade four students were ca.tegorized as either high or low anxious subjects as per Gillis' Child Anxiety Scale (a self-report general measure). In determining impulsivity in their response tendencies, via Kagan's Ma.tching Familiar Figures Test, a significant difference between the two groups was not found to exist. Training procedures (verbal labelling plus rehearsal strategies) were introduced in modification of their learning behaviour on a visual sequential memory task. Significantly more reflective memory recall behaviour was noted by both groups as a result. Furthermore, transfer of the reflective quality of this learning strategy produced significantly less impulsive response behaviour for high and low anxious subjects with respect to response latency and for low anxious subjects with respect to response accuracy.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The goal of this study was to examine the change, over a two year period, in mothers' reports of children's challenging behaviour and family conflict as they relate to change in parenting hassles (stress) among families who have preschool children with and without communication delays. Forty-four parent-child dyads participated in this Family Resource Project study that was funded by the Canadian Language and Literacy Research Network. Thirty-one ofthese families had preschool children with communication delays and 13 children were identified as not having communication delays. Child behaviour was evaluated using the Oppositional Subscale and ADHD Index of the Conners Parent Rating Scale (CPRS-R:S), the Conflict Subscale ofthe Family Environment Scale was used to examine family conflict, and the Parent Hassles Scale was used to examine parental stress. Results showed that change in mothers' daily hassles was influenced by change in their preschool children's ADHD behaviour and change in family conflict. Change in child oppositional behaviour did not predict change in mothers' hassles scores.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Efficient optic disc segmentation is an important task in automated retinal screening. For the same reason optic disc detection is fundamental for medical references and is important for the retinal image analysis application. The most difficult problem of optic disc extraction is to locate the region of interest. Moreover it is a time consuming task. This paper tries to overcome this barrier by presenting an automated method for optic disc boundary extraction using Fuzzy C Means combined with thresholding. The discs determined by the new method agree relatively well with those determined by the experts. The present method has been validated on a data set of 110 colour fundus images from DRION database, and has obtained promising results. The performance of the system is evaluated using the difference in horizontal and vertical diameters of the obtained disc boundary and that of the ground truth obtained from two expert ophthalmologists. For the 25 test images selected from the 110 colour fundus images, the Pearson correlation of the ground truth diameters with the detected diameters by the new method are 0.946 and 0.958 and, 0.94 and 0.974 respectively. From the scatter plot, it is shown that the ground truth and detected diameters have a high positive correlation. This computerized analysis of optic disc is very useful for the diagnosis of retinal diseases

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The paper will consist of three parts. In part I we shall present some background considerations which are necessary as a basis for what follows. We shall try to clarify some basic concepts and notions, and we shall collect the most important arguments (and related goals) in favour of problem solving, modelling and applications to other subjects in mathematics instruction. In the main part II we shall review the present state, recent trends, and prospective lines of development, both in empirical or theoretical research and in the practice of mathematics instruction and mathematics education, concerning problem solving, modelling, applications and relations to other subjects. In particular, we shall identify and discuss four major trends: a widened spectrum of arguments, an increased globality, an increased unification, and an extended use of computers. In the final part III we shall comment upon some important issues and problems related to our topic.