A video-based real-time vehicle detection method by classified background learning

A new two-level real-time vehicle detection method is proposed in order to meet the robustness and efficiency requirements of real world applications. At the high level, pixels of the background image are classified into three categories according to the characteristics of Red, Green, Blue (RGB) curves. The robustness of the classification is further enhanced by using<br />line detection and pattern connectivity. At the lower level, an exponential forgetting algorithm with adaptive parameters for different categories is utilised to calculate the background and reduce the distortion by the small motion of video cameras. Scene tests show that the proposed method is more robust and faster than previous methods, which is very suitable for real-time vehicle detection in outdoor environments, especially concerning locations where the level of illumination changes frequently and speed detection is important.

Describing elements of mathematics lessons that accommodate diversity in student background

We are researching actions that teachers can take to improve mathematics learning for all students. Structural elements of the lessons being trialled include making aspects of pedagogy explicit to seek to overcome differences in familiarity with schooling processes, and sequencing tasks with the potential to engage students. This article reports research on teachers building learning communities by preparing variations to set tasks in order to address differences in students&rsquo; backgrounds.<br />

Effect of carotenoids and background colour on the skin pigmentation of Australian snapper Pagrus auratus (Bloch & Schneider, 1801)

Three 2-factor experiments were conducted to determine the effects of background colour and synthetic carotenoids on the skin colour of Australian snapper Pagrus auratus. Initially, we evaluated the effects on skin colour of supplementing diets for 50 days with 60 mg kg^&minus;1 of either astaxanthin (LP; Lucantin^&reg;Pink), canthaxanthin (LR; Lucantin^&reg; Red), apocarotenoic acid ethyl ester (LY; Lucantin^&reg; Yellow), selected combinations of the above or no carotenoids and holding snapper (mean weight=88 g) in either white or black cages. In a second experiment, all snapper (mean weight=142 g) from Experiment 1 were transferred from black to white, or white to white cages to measure the short-term effects of cage colour on skin <i>L*</i>,<i> a*</i> and <i>b*</i> colour values. Skin colour was measured after 7 and 14 days, and total carotenoid concentrations were determined after 14 days.<br /><br />Cage colour was the dominant factor affecting the skin lightness of snapper with fish from white cages much lighter than fish from black cages. Diets containing astaxanthin conferred greatest skin pigmentation and there were no differences in redness (<i>a*</i>) and yellowness (<i>b*</i>) values between snapper fed 30 or 60 mg astaxanthin kg^&minus;1. Snapper fed astaxanthin in white cages displayed greater skin yellowness than those in black cages. Transferring snapper from black to white cages increased skin lightness but was not as effective as growing snapper in white cages for the entire duration. Snapper fed astaxanthin diets and transferred from black to white cages were less yellow than those transferred from white to white cages despite the improvement in skin lightness (<i>L*</i>), and the total carotenoid concentration of the skin of fish fed astaxanthin diets was lower in white cages. Diets containing canthaxanthin led to a low level of deposition in the skin while apocarotenoic acid ethyl ester did not alter total skin carotenoid content or skin colour values in snapper.<br /><br />In a third experiment, we examined the effects of dietary astaxanthin (diets had 60 mg astaxanthin kg^&minus;1 or no added carotenoids) and cage colour (black, white, red or blue) on skin colour of snapper (mean weight=88 g) after 50 days. Snapper fed the astaxanthin diet were more yellow when held in red or white cages compared with fish held in black or blue cages despite similar feed intake and growth. The skin lightness (<i>L*</i> values) was correlated with cage <i>L</i>* values, with the lightest fish obtained from white cages. The results of this study suggest that snapper should be fed 30 mg astaxanthin kg^&minus;1 in white cages for 50 days to increase lightness and the red colouration prized in Australian markets.<br />

Changes in skin colour and cortisol response of Australian snapper Pagrus auratus (Bloch & Schneider, 1801) to different background colours

A two-factor experiment was carried out to investigate the change in skin colour and plasma cortisol response of cultured Australian snapper Pagrus auratus to a change in background colour. Snapper (mean weight=437 g) were held in black or white tanks and fed diets containing 39 mg unesterified astaxanthin kg^&minus;1 for 49 days before being transferred from white tanks to black cages (WB) or black tanks to white cages (BW). Skin colour values [<i>L^*</i> (lightness), <i>a^*</i> (redness) and <i>b^*</i> (yellowness)] of all snapper were measured at stocking (<i>t</i>=0 days) and from cages of fish randomly assigned to each sampling time at 0.25, 0.5, 1, 2, 3, 5 and 7 days. Plasma cortisol was measured in anaesthetized snapper following colour measurements at 0, 1 and 7 days. Fish from additional black-to-black (BB) and white-to-white (WW) control treatments were also sampled for colour and cortisol at those times. Rapid changes occurred in skin lightness (<i>L^*</i>values) after altering background colour with maximum change in <i>L^* </i>values for BW and WB treatments occurring within 1 day. Skin redness (<i>a*</i>) of BW snapper continued to steadily decrease over the 7 days (<i>a*</i>=7.93 &times; e^{&minus;0.051 &times; time}). Plasma cortisol concentrations were highest at stocking when fish were held at greater densities and were not affected by cage colour. The results of this study suggest that transferring dark coloured snapper to white cages for 1 day is sufficient to affect the greatest benefit in terms of producing light coloured fish while minimizing the reduction in favourable red skin colouration.<br />

Modification of the visual background increases the conspicuousness of golden-collared manakin displays

Effective visual communication requires signals that are easy to detect, transmit, receive, and discriminate. Animals can increase the probability that their visual signals would be detected by evolving signals that contrast with their visual background. Animals can further enhance this contrast by behaviorally modifying the existing visual background. Male golden-collared manakins (Manacus vitellinus) clear leaf litter from the ground to form courts, which are used as display arenas. Using reflectance measures of the signal (male plumage) and the visual background (cleared court and adjacent litter), the irradiance measures of ambient light during display, and published measures of photoreceptor sensitivity of a Passerine, we test the hypothesis that court-clearing augments the contrast between male plumage and the visual background. We find that the chromatic and brightness contrasts of golden patches used during courtship are greater against the cleared court than against adjacent litter. In addition, we find that cleared courts provide a less variable background for these color patches, resulting in displays that consistently contrast the visual background. These results suggest that behavioral modification of the visual background may act to increase the conspicuousness of colorful male plumage during display, providing an explanation for why golden-collared manakins, and possibly other species, build or clear display courts. <br />

Effect of social background on the development of probabilistic concepts

This research explores how the social backgrounds of a group of students contributed to their intuitive knowledge in probabilistic reasoning, and influenced their processing of the associated mathematics. A group of Year 11 students who came from families for whom the phenomenon of track gambling formed an important part of their cultural background was identified. Another group consisting of students in the same mathematics course (Year 11 Maths in Society) but from families for whom the phenomenon of gambling in any form was totally absent from their social backgrounds was identified. Twenty students were selected from each group. The research employed a qualitative methodology in which a phenomenographic approach was used to investigate the qualitatively different ways in which individuals within the two groups thought about concepts involving probabilistic reasoning, and processed the related mathematical skills and concepts. The cognitive processes involved in the applications of probabilistic and related mathematical concepts in a variety of both gambling and non-gambling situations were studied in order to determine whether this culturally based knowledge could be viewed as a type of ‘ethnomathematics.’ Data were obtained through individual structured interviews which enabled patterns of reasoning to be compared and contrasted. Analyses of these data enabled intuitive mathematical understandings possessed by the gamblers not only to be identified, but also to be linked with their social backgrounds. Also differences between how individuals in the two groups processed probabilistic and associated mathematical knowledge were determined. This research complements and extends existing knowledge and theories related to culturally-based mathematical knowledge. Implications for further research, for classroom teaching, and for curriculum development in the study of probability in senior secondary mathematics classes are discussed.

Mental health and life satisfaction of young Australians : the role of family background

This paper uses the Household, Income and Labour Dynamics in Australia Survey to investigate the factors that influence young Australians&rsquo; mental health and life satisfaction, with an emphasis upon the role of family background. It also explores male and female differences concerning those background effects. The results indicate a particularly significant negative association between parental divorce and well-being, and suggest that the timing of divorce matters. Distinguishing the samples by gender shows that this relationship remains significant only for females. Past living arrangements consistently turn out to be statistically insignificant whether the sample used is the total, males or females. The current living arrangements, however, appear to be significantly associated with both mental health and life satisfaction of males. Adding potentially confounding characteristics to our basic regression, which includes only the family background variables, suggests that some of the &lsquo;aggregate&rsquo; effects of family background might work indirectly through the mediating variables such as education or lifestyles, though most of them remain direct. Among those, marital status, education, labour market experience and lifestyles seem to be the major factors explaining the dispersion in well-being of young Australians. Income and wealth, on the other hand, have only a minor impact.<br />

Optimal redistribution when educational background matters

Higher education plays an important role in determining individuals lifetime<br />earnings. In turn, the decision to become educated depends to a large extent on innate ability and on family characteristics, including both family<br />wealth and educational background. In this paper, we abstract from family<br />income differences to concentrate on the effects of fiscal policies on the<br />decision to undertake higher education when the educational background<br />matters. In a dynamic framework, where successive generations are linked by educational background, we consider a government that uses both linear income taxation and a lump-sum subsidy to education. Conditions for<br />optimality of each policy are derived. The factors that determine the sign<br />and magnitude of the tax rate and the subsidy are identified and include<br />concerns for redistribution, efficiency and the educational externality on<br />future generations<br />

Background paper : "Aid effectiveness and selectivity : integrating multiple objectives into aid allocation"

Research on development aid has largely focused on the effectiveness of these transfers in promoting growth or on their allocation among developing countries. Rarely if ever did these research areas intersect, in that studies seeking to explain observed or prescribe optimal inter-country aid allocations did not take into account effectiveness issues and vice versa. Collier and Dollar (C-D, 2002), in a move broadly consistent with the IDA&rsquo;s long-standing approach to its country allocation system, changed this state of affairs with their &ldquo;aid selectivity&rdquo; approach to inter-country aid allocation. C-D, building on the empirical work of Burnside and Dollar (B-D, 1997, 2000), which concluded that the effectiveness of aid in promoting growth depended on the policy regimes of recipient countries, derived &ldquo;poverty efficient&rdquo; inter-recipient aid allocations. According to the prescriptive C-D selectivity approach, optimal aid allocation favours countries with high levels of poverty, low per capita incomes and sound policy regimes. Such allocations are considered poverty efficient by maximising the number of people pulled out of poverty. Countries with unsound policies regimes receive less aid in the C-D selectivity approach as these regimes lessen aid&rsquo;s impact on growth and thus poverty reduction.<br />