An investigation of the development of navigation design guidelines for online educational applications delivery to a primary school audience

Despite growing interest in educational websites for children, there has been surprisingly little research conducted into the design of websites intended for a younger audience. This research aims to determine how the design principles identified in the extant body of literature, might be fused with the development practices currently employed within a focus organisation (case study organisation), to synthesise and partially validate a set of website navigation design guidelines for use when developing website navigation for primary school students, between the ages of nine and twelve years.

Terminal approach navigation for autonomous robots in a sensory network

In this paper we present a technique based on precision guidance approach for the sensor delivery and reception problem between two mobile robots. A slave robot is employed to collect sensors and slack them on a tray carried by the mobile master robot. We define the terminal attitude of the slave robot with respect to the master and present a LQR control approach to solving the problem of achieving a desired terminal approach angle necessary for the appropriate sensor delivery. The approach criteria is defined in terms of both minimizing the miss distance and controlling the slave robot's body attitude with respect to the master robot at the terminal point.

Robust terminal attitude navigation for autonomous vehicles

Here we define the terminal attitude of the pursuer with respect to a target and present a LQR and H¿ control approach to solving the problem of pursuer achieving a desired terminal attack/approach angle. The intercept or engagement criteria is defined in terms of both minimizing the miss distance and controlling the pursuer's body attitude with respect to the target at the terminal point. This approach in comparison to previous approaches consider the relativistic approach of the pursuer with respect to the target as opposed the absolute velocities of the two dynamic bodies, and have possible applications ranging from autonomous vehicle entry in to a mother craft to nossle engagements in on-flight refuelling or even in precision missile guidance. Here we also suitably formulate the H¿ control ideas directly applicable to the underlying problem and presents both state feedback and output feed back results for the case of finite horizon and non-zero initial conditions together with a optimal parameter value to achieve a desired terminal characteristic in terms of the original weighting parameters.

A usability instrument for evaluating websites-navigation elements

Many small businesses websites have become an important advertising medium. However little consideration is given to how these websites might be made more effective. Many factors impact on website effectiveness, including navigation. Research here describes a usability instrument developed for evaluating small business websites and uses navigation as an example of its application. The research found that the quality of navigation does have an impact on ease-of-use of a site, user's emotional response and frustration levels and a user's intention to return to that website. The research also established the statistically significant elements that contribute to navigation.

Information navigation and knowledge discovery in virtual communities

Over the past decade, advances in the Internet and media technology have literally brought people closer than ever before. It is interesting to note that traditional sociological definitions of a community have been outmoded, for community has extended far beyond the geographical boundaries that were held by traditional definitions (Wellman & Gulia, 1999). Virtual or online community was defined in such a context to describe various forms of computer-mediated communication (CMC). Although virtual communities do not necessarily arise from the Internet, the overwhelming popularity of the Internet is one of the main reasons that virtual communities receive so much attention (Rheingold, 1999). The beginning of virtual communities is attributed to scientists who exchanged information and cooperatively conduct research during the 1970s. There are four needs of participants in a virtual community: member interest, social interaction, imagination, and transaction (Hagel & Armstrong, 1997). The first two focus more on the information exchange and knowledge discovery; the imagination is for entertainment; and the transaction is for commerce strategy. In this article, we investigate the function of information exchange and knowledge discovery in virtual communities. There are two important inherent properties embedded in virtual communities (Wellman, 2001):

Trajectory characterizations for a discrete-time bearing-only navigation strategy

In this paper we explore the geometry of a particular navigation scheme which guides a pursuer from a fixed initial position to a given fixed final position using a one-step look ahead strategy and using only bearing measurements. We explicitly characterize the optimal trajectories for the problem in terms of the Cramer-Rao bound such that the derived trajectories permit a minimization in the error of an unbiased estimate of the target position.

Optimal trajectory characterization for a pursuer navigation scheme

In this paper we examine the geometry of a number of bearing-only navigation schemes for guiding a pursuer from a fixed initial position to a final target position. We explicitly characterize the optimal trajectories for the given problems in terms of analyzing those trajectories which attempt to minimize the error in an estimate of the target position using successive bearing measurements made along the trajectory.

Diver navigation system acoustic signal encoding/decoding optimisation

This thesis describes the optimisation of the encoding and decoding processes used to transmit and receive frequency coded data tones acoustically during the operation of an underwater diver navigation system. The aim was to reduce the time required to both generate these data tones for transmission as well as to decode these tones during reception. Encoding of the data tones is performed using a phase lock loop under the control of a microcontroller. A technique was developed which combined both hardware and software modifications to effectively halve the phase lock loop settling time, and therefore the time required to generate these tones. Decoding of these data tones is achieved using the Fast Fourier Transform. Alternative forms of the Discrete Fourier Transform were explored to find the most efficient in terms of execution time. Numerous software optimisations were then applied which led to a reduction in program execution time of 54 % with no penalty in program complexity or length. Testing of the system under identical real-life operating conditions showed no evidence of any system performance degradation as a result of these optimisations.

On the geometry of localization, tracking and navigation

The thesis characterizes the geometry of certain localization, tracking and navigation problems. For instance, the potential localization performance of certain multi-sensor systems is measurably linked to the relative sensor-target geometry. Additionally, several optimal and robust algorithms for localization and tracking are designed which exploit the underlying geometry of the problem considered.

Navigation of four-wheel-steering mobile robots using robust fault-tolerant sliding mode control

This paper addresses the leader-follower tracking problem of a four-wheel-steering robot subjected to nonlinear uncertainties. Two control laws have been developed, based on the adaptive sliding mode method and the adaptive input-output feedback linearization method. The proposed control schemes have been tested by means of simulations.

Contextual navigation in a multimedia journal

This work presents a framework for multimedia journaling,maintaining strong relationships between the document and embedded media. This enables media archives that are robust to changes in software environments, such as changes in web-sharing services, proprietary file formats and enables portability across operating system. We develop a journaling application using an existing multimedia framework, and show the power of the paradigm with specific case studies.