Understanding travel behavior using demographic and socioeconomic variables as travel constraints

Samdahl and Jekubovich (1997) view constraints as a subset of reasons for not engaging in a particular behavior. There is limited empirical research on the role of demographic and socioeconomic variables as travel constraints. This study investigates the relationships between a wide range of short and long trip planning and travel behaviors and sociodemographic constraints comprised of age, income and life cycle.

This research uses data generated from a cross-sectional, self-completed survey on travel and tourism which was collected during 2003 and 2004 from 49,105 Australian respondents. This paper utilizes binomial regression to find that age, income and life stage have significant differential and interactive effects on travel behavior. The results show that sociodemographic variables act in different ways to constrain/free different types of travel behavior. Implications are provided for national and state based tourism authorities. There is a need to understand these phenomena. Current research is addressing these issues.

Revised stratigraphy of the Blanchetown Clay, Murray Basin: age constraints on the evolution of paleo Lake Bungunnia

Paleo Lake Bungunnia covered more than 40 000 km2 of southern Australia during the Plio-Pleistocene, although the age and origin of the lake remain controversial. The Blanchetown Clay is the main depositional unit and outcrop at Nampoo Station in far-western New South Wales provides the most continuous lacustrine section preserved in the basin. Here the Blanchetown Clay represents the maximum lake fill and comprises: (i) a basal well-sorted sand with interbedded clay (Chowilla Sand), representing initial flooding at the time of lake formation; (ii) a thick sequence of green-grey clay comprised dominantly of kaolinite and illite, with the apparently cyclic occurrence of illite interpreted to represent cool and dry glacial climatic intervals; and (iii) a 2.6 m-thick sequence of finely laminated silt and silty clay, here defined as the Nampoo Member of the Blanchetown Clay. New magnetostratigraphic data constrain the age of the oldest lake sediments to be younger than 2.581 Ma (Matuyama-Gauss boundary) and probably as young as 2.4 Ma. This age is significantly younger than the age of 3.2 Ma previously suggested for lake formation. The youngest Blanchetown Clay is older than 0.781 Ma (Brunhes-Matuyama boundary) and probably as old as 1.2 Ma. The Nampoo Station section provides a framework for the construction of a regional Plio-Pleistocene stratigraphy in the Murray Basin.

Investigation of the intersection of constraints model of motion perception

The direction and speed of motion of a one-dimensional (1-D) stimulus, such as a grating, presented within a circular aperture is ambiguous. This ambiguity, referred to as the Aperture Problem (Fennema & Thompson, 1979) results from (i) the inability to detect motion parallel to grating orientation, and (ii) the occlusion of border information, such as the ‘ends’ of the grating, by the surface forming the aperture, Adelson and Movshon's (1982) intcrsection-of-constraints (IOC) model of motion perception describes a two-stage method of disambiguating the motion of 1-D moving stimuli (e.g., gratings) to produce unambiguous motion of two-dimensional (2-D) objects (e.g., plaid patterns) made up of several 1-D components. Specifically, in the IOC model ambiguous 1-D motions extracted by Stage 1 component-selective mechanisms are integrated by Stage 2 pattern-selective mechanisms to produce unambiguous 2-D motion signals. ‘Integration’ in the context of the IOC model involves determining the single motion vector (i.e., combination of direction and speed) which is consistent with the I-D components of a 2-D object. Since the IOC model assumes that 2-D objects undergo pure translation (i.e., without distortion, rotation, etc.), the motion vector consistent with all 1-D components describes the motion of the 2-D object itself. Adelson and Movshon (1982) propose that neural implementation of the computation underlying the IOC model is reflected in the perception of coherent 2-D plaid motion reported when two separately-moving ‘component’ gratings are superimposed. Using these plaid patterns the present thesis assesses the IOC model in terms of its ability to account for the perception of 2-D motion in a variety of circumstances. In the first series of experiments it is argued that the unambiguous motion perceived for a single grating presented within a rectangular aperture (i.e., the Barberpole illusion; Wallach, 1976) reflects application of the IOC computation to the moving 1-D grating and the stationary boundary of the aperture. While contrary to the assumption which underlies the IOC model (viz., that integration occurs between moving 1-D stimuli), evidence consistent with the involvement of the IOC computation in mediating the Barberpole illusion (in which there is only one moving stimulus) is obtained by measuring plaid coherence as a function of aperture shape. It is found that rectangular apertures which bias perceived component motions in directions consistent with plaid direction facilitate plaid coherence, while rectangular apertures which bias perceived component motions in directions inconsistent with plaid direction disrupt plaid coherence. In the second series of experiments, perceived directions of motion of type I symmetrical, type I asymmetrical, and type II plaids are measured with the aim of investigating the deviations in plaid directions reported by Ferrera and Wilson (1990) and Yo and Wilson (1992). Perceived directions of both asymmetrical and type II plaids are shown to deviate away from lOC-predicted directions and towards mean component direction. Furthermore, the magnitude of these deviations is being proportional to the difference between lOC-predicted plaid direction and mean component direction. On the basis of these directional deviations, modification to the IOC model is proposed. In the modified IOC model it is argued that plaid perception involves (i) the activity of Stage 2 pattern-selective mechanisms (and the Stage 1 component-selective mechanisms which input into these pattern-selective mechanisms) involved in implementing the IOC computation, and (ii) component-selective mechanisms which influence plaid perception directly, and ‘extraneously’ to the IOC computation. In the third series of experiments the validity of this modified IOC model, as well as the validity of alternative one-stage models of plaid perception are assessed in relation to perceived directions of plaid-induced MAEs as a function of both plaid direction and mean component direction. It is found that plaid-induced MAEs are shifted away from directions opposite to lOC-predicted plaid direction towards the direction opposite to mean component direction. This pattern of results is taken to be consistent with the modified IOC model which predicts the activity, and adaptation both of mechanisms signalling plaid direction (via implementation of the IOC computation), and ‘extraneous-type’ component-selective mechanisms signalling component directions. Alternative one-stage models which predict the adaptation of only mechanisms signalling plaid direction (the feature-tracking model), or the adaptation only of mechanisms signalling component directions (the distribution-of-activity model), cannot account for the directions of plaid-induced MAEs reported. The ability of the modified IOC model to account for the perceived directions of (i) gratings in rectangular apertures, (ii) various types of plaid in circular apertures, and (iii) directions of plaid-induced MAEs, is interpreted as supporting the proposition that human motion perception is based on a parallel and distributed process involving Stage 2 pattern-selective mechanisms (and the Stage 1 component-selective mechanisms which input into these mechanisms) taken to implement the IOC computation, and component-selective mechanisms taken to provide an 'extraneous' direct contribution to motion perception.

Using everyday experiences in teaching secondary mathematics in Malawi : possibilities and constraints for change

Proponents of socially and culturally oriented mathematics education have argued that teaching approaches which value and connect with the learner's prior knowledge and everyday experience are more likely to promote active, meaningful, relevant and liberatory learning than approaches which rely on transmission and abstract presentation of mathematical content. In Malawi, proposals to reform the outdated secondary mathematics curriculum have been made with the aim of aligning mathematics instruction with the social and political changes in the current Malawian society. Using a case study approach, this study investigated the extent to which everyday experiences could be used as a vehicle for changing the learning and teaching of secondary mathematics in Malawi. The study was collaborative, taking place over a period of five months in severely overcrowded and poorly resourced classes in two schools. It involved three mathematics teachers in a cycle of planning and teaching mathematics lessons based on the use of everyday experiences, and observation of and reflection on these lessons, in order to document the effects of using everyday experiences on student learning and teachers' teaching practices. The data was collected through student questionnaires; classroom observations and fieldnotes; interviews and reflective meetings with teachers; and informal meetings with key education officials in Malawi. Mathematics examination results from students involved in this study and a corresponding group from the previous year were collected. A reflective and critical approach was adopted in the interpretation and discussion of the data. Teachers' participation in this study resulted in heightened awareness of their teaching roles and the value of linking school mathematics with everyday experience. The study also shows that students found mathematics interesting and important to learn despite their lack of success in it. In addition, the study documented a number of constraints to change in mathematics instruction such as teachers' focus on mathematics content and examination requirements, and students' resistance to inquiry learning. It also recorded possibilities and barriers to collaboration both between teachers and researchers, and teachers themselves. The findings of this study are timely since they could serve to inform the reform of the Malawian secondary mathematics curriculum currently being undertaken, which began without a critical examination of the classroom conditions necessary to accommodate a socio-politically relevant mathematics education.

Australian teaching and learning centres through the eyes of their directors : characteristics, capacities and constraints

This paper is based on research to identify common factors that contribute to the effective strategic leadership of teaching and learning centres. The second of three phases of data collection involved a survey of Directors of Australian teaching and learning centres. The data collected were quantitatively analysed using a range of descriptive, parametric and non-parametric techniques. Based on a response rate of 81.6 percent, we present a contemporary, comprehensive and representative quantitative snapshot of Australian teaching and learning centres, as seen through the eyes of their Directors. The time since last restructure, incumbency of the current Director and total Directorship experience of the current Centre Director all have mean values of ‘sometime in the previous one to three years’. Most Centres would consider their work in the areas of ‘recognition and reward’ and ‘professional development of staff’ as high impact functions, and they would be pleased with their efforts in the former area, and wish to perform better on the latter. The principal constraint identified by Centres was ‘lack of staff time’, both in the Faculties and in the Centre, to engage in teaching and learning improvement activities. Overall, Centres feel well included in relevant university committees and other activities.

Geometric and material constraints in parametric modelling : the design to fabrication process

Parametric modelling, commonly used in the automotive and aerospace industries, has recently been adopted in the architecture and construction fields. The ability to design small repeatable components and apply them to a larger governing surface geometry is one area of parametric modelling that has great design potential. This two level modelling control, of component and overall surface, can allow designers to explore new types of form generation subject to parametric constraints. This paper reports on the design to fabrication process using repeatable components over a governing or carrier surface. The paper reports on our study of the requirements and possible solutions for successfully controlling a repeatable element, known as a Representative Volumetric Element (RVE), using geometric parameters of a larger governing surface geometry and material properties. This modelling process, coupled with Rapid
Manufacturing (RM) and Computer Numerically Controlled (CNC) machines has the potential to significantly reduce the interface between design and fabrication.

Utilizing and adapting leisure constraints models to enhance 'short-break' vacations : case study of Melbourne, Australia

Short-break tourism is likely to continue as a popular vacation for time-, income- and special interest conscious tourists. With the competition for visitors, destinations need to consider the constraints and facilitators associated with tourist decision-making for short-break vacations. This study presents the application of a leisure model toward better explaining such vacation choices. This study found key constraints, such as time and awareness, inhibited visitors from visiting attractions. The importance and influence of word-of-mouth recommendations plays a key role in gaining the attention of future visitors.

A practical approach to achieving agility : a theory of constraints perspective

This article documents an action research (AR) project aimed at identifying the practical steps needed to become an agile manufacturer through a combination of the theory of constraints (TOC) and resource- based view (RBV) approaches in a small to medium enterprise (SME) in the Australian manufacturing sector. To date, lean production has been highlighted as a possible catalyst for creating an agile manufacturer, despite the evidence suggesting that lean manufacturing lacks the responsiveness and adaptability to effectively handle a rapidly changing market place and only works well in a stable environment. A more flexible system of production is required to fully encompass the agile characteristics needed to attain a competitive advantage. This research provides empirical evidence that the TOC perspective can be used as a practical approach for becoming an agile manufacturer. The study provides a workable approach for small firms to achieve ‘Agility’ in practice.

Evolutionary psychology and the rehabilitation of offenders : constraints and consequences

The mainstream view in criminology and correctional psychology is that evolutionary perspectives have little to offer researchers or practitioners and may in fact lead to overly reductionist and crude responses to the complex issue of crime and its consequences. However, in our view all the major evolutionary approaches to the explanation of human behavior have something of value to contribute, with niche construction providing a particularly useful lens upon crime and its management. In this paper we analyze the concept of rehabilitation and describe the key features of effective rehabilitation. We argue that niche construction is responsive to the cognitive versatility and behavioral flexibility of human beings and can also accommodate the important role of social and cultural scaffolding in the rehabilitation process.

Time and energy constraints in demanding phases of the annual cycle : an example of time limitation in refuelling migratory swans

The daily metabolizable energy intake of an animal is potentially limited by either the available feeding time or by its capacity to process energy. Animals are generally considered not to be time-limited but rather to be energy-processing-limited. This is concluded from the common observation that an animal's feeding time per day increases with a decrease in food density. We argue that such changes in feeding time are in theory also expected when no constraints are operating. Thus, a study of the constraints on energy intakes of free-living animals should be performed during demanding phases of the year. As an example, we collected data on time and energy budgets of Bewick's swan (Cygnus columbianus bewickii) refuelling during migration on fennel pondweed (Potamogeton pectinatus) tubers in two years differing two-fold in tuber biomass density. As predicted by time limitation, the feeding time (defined as the time with the head submerged) did not change in response to a change in food biomass density, both within and between years (averaging 12.2 h d⁻¹). Contrary to energy-processing limitation, and again in line with time limitation, the daily metabolizable energy intake varied, being greater in the year with high than in the year with low food densities. We conclude that more studies are needed of animals operating under demanding conditions before it can be assessed whether free-living animals are generally energy-processing- or time-limited.