994 resultados para preliminary communication


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In this paper, we present robust semi-blind (SB) algorithms for the estimation of beamforming vectors for multiple-input multiple-output wireless communication. The transmitted symbol block is assumed to comprise of a known sequence of training (pilot) symbols followed by information bearing blind (unknown) data symbols. Analytical expressions are derived for the robust SB estimators of the MIMO receive and transmit beamforming vectors. These robust SB estimators employ a preliminary estimate obtained from the pilot symbol sequence and leverage the second-order statistical information from the blind data symbols. We employ the theory of Lagrangian duality to derive the robust estimate of the receive beamforming vector by maximizing an inner product, while constraining the channel estimate to lie in a confidence sphere centered at the initial pilot estimate. Two different schemes are then proposed for computing the robust estimate of the MIMO transmit beamforming vector. Simulation results presented in the end illustrate the superior performance of the robust SB estimators.

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The artificial reopening of the lagoon inlet, made in Grand-Bantam in September 1987 in order to reduce the aquatic weeds proliferation, induced some environmental and fish communities alterations in the eastern part of the Ebrié lagoon (Côte d'Ivoire). A preliminary field survey made in May 1988 shows an increase in the salinity rate and an increase of the marine component among fish communities, when compared to the former ecological state of this lagoon area (reference data of 1980 and 1981).

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155Mb/s operation of an optical wireless link is achieved by using the spectral characteristics and angular emission spectra of a 7-element tracking array of 980nm RC-LEDs. Preliminary results show extension to 200 Mb/s/channel. © 2006 Optical Society of America.

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Feeding and vocal behaviours of wild black gibbons (Hylobates concolor) were observed from 1987 to 1989 in south-western Yunnan, notably H. concolor jingdongensis at Mt. Wuliang (24-degrees 18-42'N, 100-degrees 30-50'E) in the early spring of 1989. 12 plant species were observed to have been eaten by the gibbons; these included tree species, lianas and epiphytes. Approximately 21 % of feeding time was devoted to eating fruits, 61 % to leaf buds and shoots, 7 % to flowers and 11 % to leaves. The gibbons preferred fruits to leaves even though they commonly ate leaves. In this study, the morning songs (duet and solo), reponsive (territorial) songs, alarm calls and communication calls were recorded. The gibbons sang their morning songs mainly in the early morning, with a single bout lasting more than 10 min on average. The singing of a group would trigger other groups, and all groups in an area tended to sing sequentially. The morning duet song bout was dominated by an adult male. The male emitted booms, aa notes, early multimodulated figures, intermediate multimodulated figures and codas, the latter occurring only in duets following the female's great call. The female uttered great calls and abortive great calls. The subadults or juveniles also took part in the morning songs. Lone males were heard to utter solos which lasted longer than the duets of the pairs.

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The significance of the “physicality” involved in learning to play a musical instrument and the essential role of teachers are areas in need of research. This article explores the role of gesture within teacher–student communicative interaction in one-to-one piano lessons. Three teachers were required to teach a pre-selected repertoire of two contrasting pieces to three students studying piano grade 1. The data was collected by video recordings of piano lessons and analysis based on the type and frequency of gestures employed by teachers in association to teaching behaviours specifying where gestures fit under (or evade) predefined classifications. Spontaneous co-musical gestures were observed in the process of piano tuition emerging with similar general communicative purposes as spontaneous co-verbal gestures and were essential for the process of musical communication between teachers and students. Observed frequencies of categorized gestures varied significantly between different teaching behaviours and between the three teachers. Parallels established between co-verbal and co-musical spontaneous gestures lead to an argument for extension of McNeill’s (2005) ideas of imagery–language–dialectic to imagery–music–dialectic with relevant implications for piano pedagogy and fields of study invested in musical communication.

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Thesis (Ph.D.)--University of Washington, 2013

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Background Infant development is adversely affected in the context of postnatal depression. This relationship may be mediated by both the nature of early mother-infant interactions and the quality of the home environment. Aim To establish the usefulness of the Global Ratings Scales of Mother-Infant Interaction and the Infant-Toddler version of the Home Observation for the Measurement of the Environment (IT-HOME), and to test expected associations of the measures with characteristics of the social context and with major or minor depression. Method Both assessments were administered postnatally in four European centres; 144 mothers were assessed with the Global Ratings Scales and 114 with the IT-HOME. Affective disorder was assessed by means of the Structured Clinical Interview for DSM-IV Disorders. Results Analyses of mother-infant interaction indicated no main effect for depression but maternal sensitivity to infant behaviour was associated with better infant communication, especially for women who were not depressed. Poor overall emotional support also reduced sensitivity scores. Poor support was also related to poorer IT-HOME scores, but there was no effect of depression. Conclusions The Global Ratings Scales were effectively applied but there was less evidence of the usefulness of the IT-HOME. Declaration of interest None.

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Theory of mind ability has been associated with performance in interpersonal interactions and has been found to influence aspects such as emotion recognition, social competence, and social anxiety. Being able to attribute mental states to others requires attention to subtle communication cues such as facial emotional expressions. Decoding and interpreting emotions expressed by the face, especially those with negative valence, are essential skills to successful social interaction. The current study explored the association between theory of mind skills and attentional bias to facial emotional expressions. According to the study hypothesis, individuals with poor theory of mind skills showed preferential attention to negative faces over both non-negative faces and neutral objects. Tentative explanations for the findings are offered emphasizing the potential adaptive role of vigilance for threat as a way of allocating a limited capacity to interpret others’ mental states to obtain as much information as possible about potential danger in the social environment.

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Background: The cognitive bases of language impairment in specific language impairment (SLI) and autism spectrum disorders (ASD) were investigated in a novel non-word comparison task which manipulated phonological short-term memory (PSTM) and speech perception, both implicated in poor non-word repetition. Aims: This study aimed to investigate the contributions of PSTM and speech perception in non-word processing and whether individuals with SLI and ASD plus language impairment (ALI) show similar or different patterns of deficit in these cognitive processes. Method & Procedures: Three groups of adolescents (aged 14–17 years), 14 with SLI, 16 with ALI, and 17 age and non-verbal IQ matched typically developing (TD) controls, made speeded discriminations between non-word pairs. Stimuli varied in PSTM load (two- or four-syllables) and speech perception load (mismatches on a word-initial or word-medial segment). Outcomes & Results: Reaction times showed effects of both non-word length and mismatch position and these factors interacted: four-syllable and word-initial mismatch stimuli resulted in the slowest decisions. Individuals with language impairment showed the same pattern of performance as those with typical development in the reaction time data. A marginal interaction between group and item length was driven by the SLI and ALI groups being less accurate with long items than short ones, a difference not found in the TD group. Conclusions & Implications: Non-word discrimination suggests that there are similarities and differences between adolescents with SLI and ALI and their TD peers. Reaction times appear to be affected by increasing PSTM and speech perception loads in a similar way. However, there was some, albeit weaker, evidence that adolescents with SLI and ALI are less accurate than TD individuals, with both showing an effect of PSTM load. This may indicate, at some level, the processing substrate supporting both PSTM and speech perception is intact in adolescents with SLI and ALI, but also in both there may be impaired access to PSTM resources.

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The social cost of food scares has been the object of substantial applied research worldwide. In Italy, meat and dairy products are often the vectors of food-borne pathogens, and this is well known by the public. Most cases of food contamination and poisoning find their causes in the way food is handled after, rather than before purchase. However, a large fraction is still caused by mishandling at the industrial stage. With this in mind, we set out to estimate Italian households’ willingness to pay (WTP) for a reduction in the risk of meat and dairy food contamination using contingent valuation. The survey design incorporated features specifically conceived to overcome difficulties faced in previous survey research, especially with respect to individualized food expenditures and risk communication. In order to achieve this objective a CAPI (computer-assisted personal interview) survey was devised to tackle two major issues which emerged in previous contingent valuation studies. The first issue is connected to the way of communicating risk to consumers in order to allow them to make optimal choices and the second one to the results deriving from these studies. In fact, estimates from contingent valuation regarding food safety are given just for single products and so marketers may find it hard to extrapolate them to the aggregate. Our results show that in Italy there are segments of consumers who would benefit from higher standards of food safety for farm animal products.

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This paper reports part of a study that examines how members of a senior management team in a public sector organisation make decisions under urgency. Four regional managers, who are geographically dispersed around New Zealand were interviewed, either face-to-face or via telephone, regarding their experiences of decision making under urgency.

Preliminary results indicate that only three out of a possible seven steps of a conventional decision making process are used during the urgent decision making process. The study also shows that participants do not fully utilise the information and communication technology available during the decision making process. The implications the findings have for practice and research are discussed.

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Study investigating the telecommunication information needs of people with communication disabilities in Australia. Participants were informed about the project through flyers, letters, e-mail, disability agency contacts, and Web sites. A survey with multiple choice and closed and open-ended items was developed. People with communication disabilities used a hard-copy survey format to facilitate completion. Sixty-five participants age eighteen and over from Victoria, Tasmania, South Australia, and Queensland completed the survey. Preliminary results of the study indicated that the participants requested six text-based adaptations: (1) make information clear and easy to read and understand, (2) use larger print, (3) highlight the key points, (4) use dot points, (5) use visual information, such as photos and communication symbols, and (6) provide a range of oral/audio and visual formats for information. The accessibility characteristics requested by the participants called for the development of text and Web-based formats, and for the development of inclusive design guidelines. The authors concluded that further investigation was required to determine the best possible method of making the information accessible.

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Since the September 11,2001 terrorist attacks in New York City, many countries including Australia have been able to justify the use of biometric devices for identification and surveillance of their own citizens and others in the name of national security.

This paper reports on the preliminary findings of a survey that examined Australians' views and experiences with the use of biometric devices in everyday situations in the context of their potential to serve as a 'Panopticon' to keep the nation's citizenry under surveillance. It discusses the adoption of the new communication technology from the point of view of the Justification model that sees technology choice as social
gambling and the pluralist view of technology that sees technology as neutral in itself but as having negative or positive effects on society based on how It is used.

The paper proposes the need for Australian society to balance citizens' right to privacy and civil liberties with the right to stay alive and safe from terrorism and how it may be done with the necessary legal and regulator)' safeguards.