A survey of parallel computer architectures

An attempt is made to place recent architectural innovations in the broader context of parallel architecture development by surveying the fundamentals of both newer and more established parallel computer architectures and by placing these architectural alternatives in a coherent framework. The primary emphasis is on architectural constructs rather than specific parallel machines. Three categories of architecture are defined and discussed: synchronous architectures, comprising vector, SIMD (single-instruction-stream, multiple-data-stream) and systolic machines; MIMD (multiple-instruction-stream, multiple-data-stream) with either distributed or shared memory; and MIMD-based paradigms, comprising MIMD/SIMD hybrid, dataflow, reduction, and wavefront types     

A survey of point-based techniques in computer graphics

In recent years point-based geometry has gained increasing attention as an alternative surface representation, both for efficient rendering and for flexible geometry processing of highly complex 3D-models. Point-sampled objects do neither have to store nor to maintain globally consistent topological information. Therefore they are more flexible compared to triangle meshes when it comes to handling highly complex or dynamically changing shapes. In this paper, we make an attempt to give an overview of the various point-based methods that have been proposed over the last years. In particular we review and evaluate different shape representations, geometric algorithms, and rendering methods, which use points as a universal graphics primitive.     

A survey of issues in computer network security

Computer networks are proliferating rapidly for a number of reasons discussed in this paper. During this boom, relatively little attention has been paid to computer network security. This paper describes problems posed by network security and presents a survey of methods and technologies available today to enhance network security. Current methods are discussed, including information security strategy, computer security and its relation to network security, data communications security, and data encryption. Ideas from promising areas of research close the paper.     

A survey of computer crime legislation in the United States

This article surveys federal and state computer crime legislation in the US. In addition to one principal federal statute, more than two‐thirds of the states have laws in place, with legislative activity ongoing in many jurisdictions. Despite wide variation in the structure and wording of these statutes, almost all work to prohibit unauthorized access to or use of computers and databases, the use of a computer as an instrument of fraud, and most presently foreseeable forms of computer sabotage. The application of the federal statute to a particular transaction requires interstate activity or connections. The evidence of successful enforcement is patchy, although in recent years there has been a significant increase in the resources devoted to the problem. There are few reported court decisions to shed light on the interpretive ambiguities that many of the statutes have created.     

Wrist postures in the general population of computer users during a computer task

Computer activities have commonly been linked to the development of musculoskeletal disorders (MSDs) in the upper limbs. However, to understand the effects computer use has on such disorders, it is necessary to identify and classify the movements involved in performing common computer tasks, one of these being typing. Motion analysis techniques were adopted to determine the movements involved during a typing task. This involved markers being placed on the knuckles, wrists and forearms of participants. This marker configuration allowed for the flexion, extension, radial deviation, ulnar deviation and a combination of these movements to be calculated. The results in one plane of motion show a mean extension|flexion and radial|ulnar deviation of 18.825°?±?10.013° and 5.228°?±?11.703° respectively. The most common position in two planes of motion was 20° extension with a simultaneous 20° ulnar deviation (10.72%). The results depict an alternative method of categorizing wrist positions in two planes during computer use. Coincident wrist postures should be addressed as opposed to motion in a single plane as these postures may result in different ergonomic risk factors developing.     

A survey of digital computer memory systems

Many types of storage and memory systems have been proposed for use in digital computing systems. The survey paper discusses only the various systems whose reaction time is faster than human reaction time and employs a historical approach to the subject. Criteria for evaluation are discussed as well as comparisons among the different systems as to general applicability, ease of construction and use, speed of operation, latency time, memory span, and economy     

Usage control in computer security: A survey

Protecting access to digital resources is one of the fundamental problems recognized in computer security. As yet it remains a challenging problem to work out, starting from the design of a system until its implementation. Access control is defined as the ability to permit or deny access to a particular resource (object) by a particular entity (subject). Three most widely used traditional access control models are: Discretionary Access Control (DAC), Mandatory Access Control (MAC), and Role Based Access Control (RBAC).Traditional access control solutions do not respond adequately to new challenges addressed by modern computer systems. Today highly distributed, network-connected, heterogeneous and open computing environment requires a fine-grained, flexible, persistent and continuous model for protecting the access and usage of digital resources.This paper surveys the literature on Usage Control (UCON) model proposed by Park and Sandhu (2002) [1], Park (2003) [2] and Zhang (2006) [3]. Usage control is a novel and promising approach for access control in open, distributed, heterogeneous and network-connected computer environments. It encompasses and enhances traditional access control models, Trust Management (TM) and Digital Rights Management (DRM), and its main novelties are mutability of attributes and continuity of access decision evaluation.     

A survey of blind users on the usability of email applications

Blind users face many challenges and obstacles when using computers at home and in the workplace, including difficulties in accessing web sites and using corporate software. A detailed understanding of usability problems in common email applications can inform designs that will provide improved usability. To help understand the challenges faced, a web-based survey on email usage by blind screen reader users was conducted. This paper presents the results of the survey of 129 blind users, which reveal several important facets of email applications that can be improved for blind users. The paper also discusses the specific challenges that are faced by blind users when using desktop and web-based email software.     

A microcomputer training system for electric wheelchair users

The problem addressed by this paper is the need to assess a severely physically handicapped person's ability to drive a joystick controlled electric wheelchair, and the parallel need for training in the use of a motorised chair. The only alternative assessment method is to obtain a motorised chair and place the person being assessed in it. This can involve considerable wasted expense if a chair is bought which subsequently proves to be unsuitable. When an unskilled person is practising using a motorised wheelchair constant supervision is necessary, which can be very time consuming.This paper outlines the development of a computer-based means of assessment and training for motorised wheelchair users. A suite of programs has been developed to run on a BBC microcomputer, which allows the ability of a severely physically handicapped person to be tested. The assessments which can be made include tests of the ability to make simple joystick movements in response to a prompt, and more complex investigations of the skills necessary to guide a wheelchair around barriers and obstacles. In addition to their use for assessment the programs can be used repeatedly for training, and a point-scoring system is included to indicate what improvement has been made.The software has been developed to resemble a computer game to facilitate its use with children, and makes extensive use of the BBC computer's colour graphics and sound generator. The software has been used by a number of establishments and individuals, and some user reactions are included in the paper.     

A survey of trust in computer science and the Semantic Web

Trust is an integral component in many kinds of human interaction, allowing people to act under uncertainty and with the risk of negative consequences. For example, exchanging money for a service, giving access to your property, and choosing between conflicting sources of information all may utilize some form of trust. In computer science, trust is a widely used term whose definition differs among researchers and application areas. Trust is an essential component of the vision for the Semantic Web, where both new problems and new applications of trust are being studied. This paper gives an overview of existing trust research in computer science and the Semantic Web.     

A comparative study of information input devices for aging computer users

The fast aging of many western and eastern societies and their increasing reliance on information technology create a compelling need to reconsider older users' interactions with computers. Changes in perceptual and motor skill abilities that often accompany the aging process have important implications for the design of information input devices. This paper summarises the results of two comparative studies on information input with 90 subjects aged between 20 and 75 years. In the first study, three input devices – mouse, touch screen and eye-gaze control – were analysed concerning efficiency, effectiveness and subjective task difficulty with respect to the age group of the computer user. In the second study, an age-differentiated analysis of hybrid user interfaces for input confirmation was conducted combining eye-gaze control with additional input devices. Input confirmation was done with the space bar of a PC keyboard, speech input or a foot pedal. The results of the first study show that regardless of participants' age group, the best performance in terms of short execution time results from touch screen information input. This effect is even more pronounced for the elderly. Regarding the hybrid interfaces, the lowest mean execution time, error rate and task difficulty were found for the combination of eye-gaze control with the space bar. In conclusion, we recommend using direct input devices, particularly a touch screen, for the elderly. For user groups with severe motor impairments, we suggest eye-gaze information input.     

A sample survey of attitudes to computer studies

There is a general concern at present that curricular and technological change affecting the education and career aspirations of school pupils is not being fully exploited by girls. Whilst there are many reasons which can be offered to explain this trend most arise from subjective analysis or are extrapolated from surveys conducted into the factors affecting the uptake of science subjects. Much research which has considered attitudes to and the uptake of computer studies/information technology in schools has tended to be based on relatively small or isolated pupil populations but in this present study the attitudes of 1500 sixth-form boys and girls have been explored using standard questionnaire techniques. The pupil population was selected to cover a range of school types, pupil social class, ability, religion and sex as the dominant label. The survey questions were framed to explore attitudes to computing and computers, aspirations towards computer-related careers and attitudes to activities such as programming and games playing. Statistical tests have been applied to the results in order to identify overall trends and to assess the significance of boy-girl agreement and disagreement on various aspects.     

Security awareness of computer users: A phishing threat avoidance perspective

Phishing is an online identity theft, which aims to steal confidential information such as username, password and online banking details from its victims. To prevent this, anti-phishing education needs to be considered. Therefore, the research reported in this paper examines whether conceptual knowledge or procedural knowledge has a positive effect on computer users’ self-efficacy to thwart phishing threats. In order to accomplish this, a theoretical model based on Liang and Xue’s (2010) Technology Threat Avoidance Theory (TTAT) has been proposed and evaluated. Data was collected from 161 regular computer users to elicit their feedback through an online questionnaire. The study findings revealed that the interaction effect of conceptual and procedural knowledge positively impacts on computer users’ self-efficacy, which enhances their phishing threat avoidance behaviour. It can therefore be argued that well-designed end-user security education contributes to thwart phishing threats.     

Verification of computer users using keystroke dynamics

This paper presents techniques to verify the identity of computer users using the keystroke dynamics of computer user's login string as characteristic patterns using pattern recognition and neural network techniques. This work is a continuation of our previous work where only interkey times were used as features for identifying computer users. In this work we used the key hold times for classification and then compared the performance with the former interkey time-based technique. Then we use the combined interkey and hold times for the identification process. We applied several neural network and pattern recognition algorithms for verifying computer users as they type their password phrases. It was found that hold times are more effective than interkey times and the best identification performance was achieved by using both time measurements. An identification accuracy of 100% was achieved when the combined hold and intekey time-based approach were considered as features using the fuzzy ARTMAP, radial basis function networks (RBFN), and learning vector quantization (LVQ) neural network paradigms. Other neural network and classical pattern algorithms such as backpropagation with a sigmoid transfer function (BP, Sigm), hybrid sum-of-products (HSOP), sum-of-products (SOP), potential function and Bayes' rule algorithms gave moderate performance.     

A survey of aging and weathering phenomena in computer graphics

Aging phenomena often play a key role in realistic rendering: excepting when the desired result is specifically a brand-new virtual object, their absence can lead to non-realistic surfaces, looking too clean and smooth. To solve these problems, artists either compose multiple textures manually, or directly modify object geometries. However, such techniques may not be suitable to obtain realistic results: aging processes are resulting from materials’ composition, objects usury, weathering conditions, and a great number of other physical, biological, and chemical parameters. To create realistic images that exhibit a specific aging process, a designer has to know how this process appears and grows, in a physicochemical way. In this paper, we will propose a survey of techniques permitting to represent aging and weathering phenomena in computer graphics. We will use a classification depending on the processes involved, as aging phenomena influence all aspects of the rendered images (texture, reflection properties, and geometry).     

The influence of computer anxiety on experienced computer users while performing complex computer tasks

This study was conducted to test the hypothesis whether computer anxiety has a hindering effect on experienced computer users while performing complex computer tasks. Participants were 75 third-year psychology students taking a Delphi programming course. Prior to the course, a computer anxiety scale was filled in. Computer performance was measured in four different ways: through final course grade, predicted final grade, self-perceived programming skills, and through observed behavior while programming a computer application. The results showed that computer anxiety was found to correlate with the students’ prediction of their final grade and with the perception of their own computer skills, but had no effect on actual performance as measured by the final course grade. Furthermore, there was no significant effect of computer anxiety on behavioral measures while students were programming a computer application. The findings point into the direction of a “threshold effect”, where anxiety only hinders performance when this anxiety is sufficiently severe or when the context in which the task to be executed on a computer is ambiguous.     

A survey of technology accessibility problems faced by older users in China

Internet accessibility for older users has become an important issue to promote inclusion and participation in the Information Society. This paper proposes an investigation into the technology accessibility problems faced by older users in China. The research reported here was conducted by means of an exploratory survey with a Web-based questionnaire and discussions with older users at meetings. The study had 180 valid answers and involved representatives from each of the 25 provinces of China. The results show that 39% of the participants cannot or can only partially access information, because of various kinds of accessibility problems. Many participants indicated that the main problems in accessing the Internet were health barriers, circumstances barriers, and Internet design barrier. The possible reason for these difficulties could be that the government doesn’t foster a social environment conducive to helping the elderly to get online and that it does not provide services for the elderly designed to help them access information electronically. The poor rate of accessibility industry for the elderly, as well as the lack of Chinese accessibility laws, is an important issue that must be dealt with to promote greater Internet accessibility for the elderly.