Evaluating websites for older adults: adherence to ‘senior-friendly’ guidelines and end-user performance

Older adults in the US are the fastest-growing demographic, and also the largest-growing group of internet users. The aim of this research was to evaluate websites designed for older adults in terms of (i) how well they adhere to ‘senior-friendly’ guidelines and (ii) overall ease of use and satisfaction. In Experiment I, 40 websites designed for older adults were heuristically evaluated based on their adherence to usability guidelines derived by the National Institute on Aging and the National Library of Medicine. In Experiment II, three websites with varying levels of guideline compliance were evaluated by older adults in a usability test. Results from this study indicate that the website most compliant with the ‘senior-friendly’ guidelines resulted in higher task success, but did not result in significantly better efficiency, satisfaction, or preference. These findings demonstrate the importance of using both guidelines and usability testing when designing websites for older adults.     

Usability evaluation of a virtual reality smartphone app for a living museum

This paper elaborates the empirical evidence of a usability evaluation of a VR and non-VR virtual tour application for a living museum. The System Usability Scale (SUS) was used in between participants experiments (Group 1: non-VR version and Group 2: VR version) with 40 participants. The results show that the mean scores of all components for the VR version are higher compared to the non-VR version, overall SUS score (72.10 vs 68.10), usability score (75.50 vs 71.70), and learnability (58.40 vs 57.00). Further analysis using a two-tailed independent t test showed no difference between the non-VR and VR versions. Additionally, no significant difference was observed between the groups in the context of gender, nationality, and prior experience (other VR tour applications) for overall SUS score, usability score, and learnability score. Α two-tailed independent t test indicated no significant difference in the usability score between participants with VR experience and no VR experience. However, a significant difference was found between participants with VR experience and no VR experience for both SUS score (t(38) = 2.17, p = 0.037) and learnability score (t(38) = 2.40, p = 0.021). The independent t test results indicated a significant difference between participant with and without previous visits to SCV for the usability score (t(38) = −2.31, p = 0.027), while there was no significant differences observed in other components. It can be concluded that both versions passed based on the SUS score. However, the sub-scale usability and learnability scores indicated some usability issue.

     

Some generalized Jacobi polynomials

We give explicitly the recurrence coefficients in the three term recurrence relation of some generalized Jacobi polynomials defined by the positive weight ϱ(α,α + p;x,μ) = 6^−μ(1−x²)^α(1−x)^p on [−1, +1]. The case p = 0 can be found in Chihara's book. The case p = 1 is treated by the first author, and we consider here the cases p = 2,3,4. These recurrence coefficients can be used to prove that their corresponding polynomials are random walk and then are of interest in birth and death process [1,2]; for instance, the cases p = 1,2 are treated.     

Accessibility,usability, and security evaluation of Hungarian government websites

Public sector bodies are increasingly relying on the Internet. On this channel, indispensable information is transmitted to the public and a wide range of services is already available. Therefore, the usability, accessibility, and the security of these websites are very important. Accessibility is particularly crucial for persons with disabilities. The accessibility of public service websites is regulated by a number of laws; among others, the directive “on the accessibility of the websites and mobile applications of public sector bodies” adopted by the European Parliament in 2016. This obliges all European Union member states to make all public sector websites and mobile applications accessible by 23 September 2021. In practice, this means that websites must fulfil the level AA recommendations in WCAG 2.1. In our study, a website assessment method is developed by comparing different analytical tools. With this method, we analysed how Hungarian websites of public sector bodies fulfil the requirements of the directive. We have also investigated how well they comply with usability and security guidelines. The results showed that none of the 25 websites of the examined Hungarian public sector bodies could completely fulfil the recommendations of the Web Content Accessibility Guidelines (WCAG) and that half of the websites had only the lowest level of compliance in usability tests. From the security point of view, almost half of the websites use outdated server versions and programming language, which is very critical. We have proposed several suggestions to address the major problems, so website developers and administrators can improve the accessibility, usability, and security aspects of these websites.

     

Effect of evaluators’ cognitive style on heuristic evaluation: Field dependent and field independent evaluators

Heuristic evaluation is a widely used usability evaluation method [Rosenbaum et al., 2000. A toolkit for strategic usability: results from workshops, panels, and surveys. In: Little, R., Nigay, L. (Eds.), In: Proceedings of ACM CHI 2000 Conference, New York, pp. 337–344]. But it suffers from large variability in the evaluation results due to differences among evaluators [Nielsen, 1993. Usability Engineering. Academic Press, Boston, MA]. The evaluation performance of evaluators with two types of cognitive styles—ten field independent (FI) subjects and ten field dependent (FD) subjects were compared. The results indicated that the FI subjects produced evaluation results with significantly higher thoroughness (t₁₈=3.49, p=0.0026), validity (t₁₈=4.26, p=0.0005), effectiveness (t₁₈=5.14, p=0.0001), and sensitivity (t₁₈=3.16, p=0.005) than the FD subjects. When assessing their own evaluation experiences, the FI subjects felt it was easier to find usability problems than the FD subjects (t₁₈=2.10, p=0.049), but the FD subjects felt more guided during the evaluation than the FI subjects (t₁₈=2.28, p=0.035).     

The Impact of Geographic Location on the Subjective Assessment of System Usability

Marketing researchers use geography to identify specific user groups for studies to more effectively describe their potential customer base. Since usability professionals often recruit users employing similar selection criteria as their marketing peers, the use of geographic information might also be relevant when selecting usability test participants. In total, 3,168 participants from across the United States rated the usability of different hardware, software, and web-based products using the System Usability Scale (SUS). SUS scores were compared across geographic divisions to determine if usability assessments differ by location. SUS scores were also compared across rural and urban areas to determine if usability assessment scores change with population density. There was a lack of evidence to support significant differences in usability scores across both US geographic areas and zones of population density. The findings suggest that people make similar system usability assessments regardless of the area of the United States in which they live.     

High and low spatial frequencies in website evaluations

Statement of Relevance:

Which features of websites are important for users' perceptions regarding aesthetics or usability? This study investigates how evaluations of aesthetic appeal and usability depend on high vs. low spatial frequencies. High spatial frequencies convey information on fine details, whereas low spatial frequencies convey information about the global layout. Participants rated aesthetic appeal and usability of 50 website screenshots from different domains. Screenshots were presented unfiltered, low-pass filtered with blurred targets or high-pass filtered with high-pass filtered targets. The main result is that low spatial frequencies can be seen to have a unique contribution in perceived website aesthetics, thus confirming a central prediction from processing fluency theory. There was no connection between low spatial frequencies and usability evaluations, whereas strong correlations were found between ratings of high-pass filtered websites and those of unfiltered websites in aesthetics and usability. This study thus offers a new perspective on the biological basis of users' website perceptions.

This research links ergonomics to neurocognitive models of visual processing. This paper investigates how high and low spatial frequencies, which are neurologically processed in different visual pathways, independently contribute to users' perceptions of websites. This is very relevant for theories of website perceptions and for practitioners of web design.     

Understanding internet recruitment via signaling theory and the elaboration likelihood model

A detailed model specifying the linkages between Internet recruitment websites and organizational attraction was examined. Participants (N = 581) viewed Fortune 500 company websites and responded to questions about the content and design of these websites and their resulting attitudes, fit perceptions, and organizational attraction. Results showed that recruitment website content and design influence attitudes toward the recruitment websites, organizational attitudes, and subsequently organizational attraction. The moderating effects of person-organization (P-O) and person-job (P-J) fit were examined. Two sets of hypotheses based on signaling theory (  and ) and the elaboration likelihood model ( Petty & Cacioppo, 1981) were largely supported. Consistent with signaling theory, the amount of job and organizational information on a recruitment website interacted with website usability, such that when less job information was presented, website usability played a greater role in predicting favorable attitudes towards the organization. Consistent with the elaboration likelihood model, when P-J fit was high, website aesthetics were less important in predicting attitudes towards the organization.     

FPGA based unified architecture for public key and private key cryptosystems

Recently, security in embedded system arises attentions because of modern electronic devices need cautiously either exchange or communicate with the sensitive data. Although security is classical research topic in worldwide communication, the researchers still face the problems of how to deal with these resource constraint devices and enhance the features of assurance and certification. Therefore, some computations of cryptographic algorithms are built on hardware platforms, such as field program gate arrays (FPGAs). The commonly used cryptographic algorithms for digital signature algorithm (DSA) are rivest-shamir-adleman (RSA) and elliptic curve cryptosystems (ECC) which based on the presumed difficulty of factoring large integers and the algebraic structure of elliptic curves over finite fields. Usually, RSA is computed over GF(p), and ECC is computed over GF(p) or GF(2 ^p ). Moreover, embedded applications need advance encryption standard (AES) algorithms to process encryption and decryption procedures. In order to reuse the hardware resources and meet the trade-off between area and performance, we proposed a new triple functional arithmetic unit for computing high radix RSA and ECC operations over GF(p) and GF(2 ^p ), which also can be extended to support AES operations. A new high radix signed digital (SD) adder has been proposed to eliminate the carry propagations over GF(p). The proposed unified design took up 28.7% less hardware resources than implementing RSA, ECC, and AES individually, and the experimental results show that our proposed architecture can achieve 141.8MHz using approximately 5.5k CLBs on Virtex-5 FPGA.     

Efficient and Scalable PRAM Algorithms for Discrete-Event Simulation of Bounded Degree Networks

We describe two new parallel algorithms, one conservative and another optimistic, for discrete-event simulation on an exclusive-read exclusive-write parallel random-access machine (EREW PRAM). The target physical systems are bounded degree networks which are represented by logic circuits. Employing p processors, our conservative algorithm can simulate up to O(p) independent messages of a system with n logical processes in O(log n) time. The number of processors, p, can be optimally varied in the range 1 ≤ p ≤ n. To identify independent messages, this algorithm also introduces a novel scheme based on a variable size time window. Our optimistic algorithm is designed to reduce the rollback frequency and the memory requirement to save past states and messages. The optimistic algorithm also simulates O(p) earliest messages on a p-processor computer in O(log n) time. To our knowledge, such a theoretical efficiency in parallel simulation algorithms, conservative or optimistic, has been achieved for the first time.     

Consumer feelings and behaviours towards well designed websites

We analysed the effect of a well designed website in terms of five indicators: purchase intention, positive attitudes, trust, satisfaction and perceived risk. These effects (measured by 21 items) were successfully combined into a single construct using Rasch's Model. The construct was then tested by building a website designed by experts for a fictitious clothes company. It was compared with four less-well-designed websites created by modifying the well designed website by removing one of the four major constructs [web security; customer service; amount and quality of information provided; and usability]. These websites were surfed by 350 consumers (in five subsamples); the experts were then asked to express their perceptions and attitudes of the sites a posteriori. The association between the five websites and the 21 items was displayed visually through a perceptual map built with DYANE software. This showed that a well designed website does not always have the best effect on all 21 items measured.     

The number of pessimistic guesses in Generalized Black-peg Mastermind

Mastermind is a famous two-player game, where the codemaker has to choose a secret code and the codebreaker has to guess it in as few questions as possible using information he receives from the codemaker after each guess. In Generalized Black-peg Mastermind for given arbitrary numbers p, c, the secret code consists of p pegs each having one of c colors, and the received information consists only of a number of black pegs, where this number equals the number of pegs matching in the corresponding question and the secret code. Let b(p,c) be the pessimistic number of questions for Generalized Black-peg Mastermind. By a computer program we compute several values b(p,c). By introducing some auxiliary games and combining this program with theoretical methods, for arbitrary c we obtain exact formulas for b(2,c), b(3,c) and b(4,c) and give upper and lower bounds for b(5,c) and a lower bound for b(6,c). Furthermore, for arbitrary p, we present upper bounds for b(p,2), b(p,3) and b(p,4). Finally, we give bounds for the general case b(p,c). In particular, we improve an upper bound recently proved by Goodrich.     

Efficient online algorithm for identifying useless states in distributed systems

In a distributed system, detecting whether a given logical predicate is true on the global states is fundamental for testing and debugging the program. Detecting predicates by examining all global states is intractable due to the combinatorial nature of the problem. This work designs an efficient online algorithm that identifies the consistent and useless states each time a new state is reported. This paper formulates the optimality of detecting algorithms in terms of pseudo states, which are employed to represent unknown states to the monitor process. Based on this technique, memory space of the debugger can be minimized by removing the useless states without affecting the debugging results. While minimizing memory space, the proposed algorithm requires only O(p ² M) time in total, where p is the number of processes, and M is the number of reported states.     

The number of pessimistic guesses in Generalized Mastermind

Mastermind is a famous two-player game, where the codemaker has to choose a secret code and the codebreaker has to guess it in as few questions as possible. The code consists of 4 pegs, each of which is one of 6 colors. In Generalized Mastermind a general number p of pegs and a general number c of colors is considered. Let f(p,c) be the pessimistic number of questions for the generalization of Mastermind with an arbitrary number p of pegs and c of colors. By a computer program we compute ten new values of f(p,c). Combining this program with theoretical methods, we compute all values f(3,c) and a tight lower and upper bound for f(4,c). For f(p,2) we give an upper bound and a lower bound. Finally, combining results for fixed p and c, we give bounds for the general case f(p,c).     

Randomized parallel list ranking for distributed memory multiprocessors

We present a randomized parallel list ranking algorithm for distributed memory multiprocessors, using a BSP type model. We first describe a simple version which requires, with high probability, log(3p)+log ln(n)=Õ(logp+log logn) communication rounds (h-relations withh=Õ(n/p)) andÕ(n/p)) local computation. We then outline an improved version that requires high probability, onlyr?(4k+6) log(2/3p)+8=Õ(k logp) communication rounds wherek=min{i?0 |ln(i+1)n?(2/3p)²ⁱ⁺¹}. Notekn) is an extremely small number. Forn andp?4, the value ofk is at most 2. Hence, for a given number of processors,p, the number of communication rounds required is, for all practical purposes, independent ofn. Forn?1, 500,000 and 4?p?2048, the number of communication rounds in our algorithm is bounded, with high probability, by 78, but the actual number of communication rounds observed so far is 25 in the worst case. Forn?10010100 and 4?p?2048, the number of communication rounds in our algorithm is bounded, with high probability, by 118; and we conjecture that the actual number of communication rounds required will not exceed 50. Our algorithm has a considerably smaller member of communication rounds than the list ranking algorithm used in Reid-Miller’s empirical study of parallel list ranking on the Cray C-90.⁽¹⁾ To our knowledge, Reid-Miller’s algorithm⁽¹⁾ was the fastest list ranking implementation so far. Therefore, we expect that our result will have considerable practical relevance.