Eiffel assertions and the external structure of classes and objects

The “external structure” in an object oriented system refers here to the  graphs of objects and classes. The class structure graph or class model is derived from the object structure graph or object model, and in this operation structural information is lost, or never made explicit. Although object oriented programming languages capture the class model as declarations,  contradictory assumptions about object model properties may be made introducing faults into the design. Consistent assumptions about the object model can be specified in the code using assertions such as Eiffel’s  invariants, preconditions and postconditions. Three examples specifying the external structure are considered.

Performance and narrative, bodies and movement in the construction of places and objects, spaces and knowledges: The case of the Maltese megaliths

The article explores the ways knowledge and space are co-produced performatively through bodily movement in an examination of the Maltese megaliths the first complex stone structures in the world. It is argued that knowledge is best seen as spatialized narratives of human actions and objects as materialized forms of those spatial narratives. Rewriting our social and historical narratives so that the performativity of place, space and knowledge is restored opens new possibilities for rethinking the social and material order.

A token-based independent update protocol for managing replicated objects

This paper presents the design and evaluation of a token-based protocol supporting independent updates of replicated objects. The paper makes three major contributions. Firstly, a token is used to simplify the control of update propagation and ordering. Secondly a partial commit state is introduced to support independent updates and to enhance the efficiency of transaction processing. Thirdly, a data partition methodology based on priorities is adopted to reduce update conflicts. We evaluate our protocol in comparison of two existing replication-control protocols in terms of transaction processing efficiency.

Automating the construction of replicated objects in a cluster of workstations

This paper describes a tool that mimics the design of the remote procedure call (RPC) system to support the building of replicated objects in a cluster of workstations (COW). The tool includes an interface definition language for describing a replica group, a language preprocessor and a runtime library system. The paper also presents one example and discusses some performance issues for replicated objects.

Grid-based method for ranking images with multiple objects

One of the content-based image retrieval techniques is the shape-based technique, which allows users to ask for objects similar in shape to a query object. Sajjanhar and Lu proposed a method for shape representation and similarity measure called the grid-based method [1]. They have shown that the method is effective for the retrieval of segmented objects based on shape. In this paper, we describe a system which uses the grid-based method for retrieval of images with multiple objects. We perform experiments on the prototype system to compare the performance of the grid-based method with the Fourier descriptors method [2]. Preliminary results have been presented.

A comparative study of computational value in visual cues used in positioning 3D objects

This paper explores the comparative computational values of using a variety of visual cues in 3D environments. The authors reflect upon the possible repercussions of computationally less expensive visual cues on users' ability to efficiently and accurately interact with three-dimensional images. This study compares the effectiveness of expensive soft shadows against less expensive hard shadows and expensive partial-occlusion (obtained by semi-transparent surface) against less expensive occlusion on users' ability to accurately position objects in imminent contact with other objects in a three-dimensional environment.

Alternating heat transfer between objects of large geometrical difference

The heat transfer on the surface of an object in a gas fluidised bed is sequentially and alternately induced by particle-packet and gas bubble. This phenomenon is studied with computational simulation. The particle-packet and bubble are modelled by a double particle-layers and porous medium model and a hemispherical model, respectively. The heat transfer to and within the object is simulated concurrently. Different grid schemes are applied and different grid sizes are used in meshing the particle-packet and the object as there is a very large difference in their geometrical sizes. Based on theoretical analysis, an approximate method is developed to calculate the heat flux at the surface of the object. The simulation is implemented in a CFD package and the results are compared with experiments.

Managing social and intellectual capital to inform design and development of learning objects : issues, applications and technologies

The purpose of this paper is to present and analyse a case example of the development and implementation of a digital learnmg object in context with academic literature in the field. The paper's content describes the creation of a multimedia learning object from conception in 2004 to completion m 2006. Provided is the rationale and outcome of a strategically funded University project aimed at illuminating an industrial case study of good management and communication practices for use in classrooms throughout the entire university. This paper is intended to act as a guide for others. Our experience as academics in successful dialogue With educational technologists will inspire and inform those embarking on similar projects, and aspects of it will generalise to development and implementation Issues for other kinds of learning objects.

Learning to detect texture objects by artificial immune approaches

This paper introduces a novel method to detect texture objects from satellite images. First, a hierarchical strategy is developed to extract texture objects according to their roughness. Then, an artificial immune approach is presented to automatically generate segmentation thresholds and texture filters, which are used in the hierarchical strategy. In this approach, texture objects are regarded as antigens, and texture object filters and segmentation thresholds are regarded as antibodies. The clonal selection algorithm inspired by human immune system is employed to evolve antibodies. The population of antibodies is iteratively evaluated according to a statistical performance index corresponding to object detection ability, and evolves into the optimal antibody using the evolution principles of the clonal selection. Experimental results of texture object detection on satellite images are presented to illustrate the merit and feasibility of the proposed method.

Programming your - objects (turtles, textboxes, sliders and buttons) in microworlds

This article outlines some new-object commands of Logo Microworlds and includes the use of buttons, sliders and programmable colours. The ability to assign object properties including font, colour and frames are discussed. As is assigning object-instructions and commands such as click on and clickoff, launch and cancel. Programming the turtle, making a new turtle, running simultaneous turtles, programming graphic colours and sliders as well as understanding dotimes are explored.

Time-to-Collision (TTC) judgements with offsize objects show that Tau needs to be intergrated with familiar size to explain TTC performance

Observers judged TTC with computer-generated displays simulating an approaching object in three familiar-size conditions:

(i) Real-size (smaller, larger objects depicted as tennis, soccer balls respectively).
(ii) Off-size (smaller, larger objects depicted as soccer, tennis balls respectively).
(iii) Ambiguous-size (smaller, larger objects depicted as texture-less black balls of different size).

Displays simulated objects approaching observersí viewpoint from 24.96 m, and disappearing at 5.76 m. Manipulation of approach velocities (4.8-19.2 msec-1) produced viewing times from 1.0 to 4.0 sec, and delays between object disappearance and tau-based TTC ranging from 0.3 to 1.2 sec. Motion characteristics of smaller and larger objects in the three familiar-size conditions simulated those of approaching real-sized tennis and soccer balls respectively; that is, for each approach velocity, tau‚-based TTC was the same across the three conditions for smaller and larger objects.

Results showed that, consistent with the proposition of tau-determined TTC, TTC estimates in the real-size condition were uninfluenced by object size. This is contrary to previous reports that TTC for larger objects is underestimated relative to TTC for smaller objects. However, such size-dependent TTC differences were found in the ambiguous-size condition, with even larger differences in the off-size condition; TTCs for the ëlargerí tennis ball were much less than TTCs to the ësmallerí soccer ball compared to corresponding TTCs in the ambiguous-size condition. These results are problematic for the proposition that tau solely determines TTC. We discuss the role of perceptual learning in resolving this problem.

Reuse of learning objects? why, how and when?

This paper describes the rationale behind the specification and acquisition of a Digital Objects Management System (DOMS) at Deakin University. Key drivers are: compliance with the provisions of the Digital Agenda Act for the communication of copyright works; improved management of Deakin’s intellectual property, and reduction in costs of delivering online content via a learning management system.

Details of the desired functionality and potential integration issues are addressed. During the specification stage, additional uses for a digital object management system were identified that relate to the broader notion of knowledge management, and these will be discussed.

At the time of writing, no decision has been made as to which vendor(s) will be successful in gaining the University’s contract for the management of digital learning objects.