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1.
People often attribute their reluctance to study texts on screen to technology-related factors rooted in hardware or software. However, previous studies have pointed to screen inferiority in the metacognitive regulation of learning. The study examined the effects of time pressure on learning texts on screen relative to paper among undergraduates who report only moderate paper preference. In Experiment 1, test scores on screen were lower than on paper under time pressure, with no difference under free regulation. In Experiment 2 the time condition was manipulated within participants to include time pressure, free regulation, and an interrupted condition where study was unexpectedly stopped after the time allotted under time pressure. No media effects were found under the interrupted study condition, although technology-related barriers should have taken their effect also in this condition. Paper learners who preferred this learning medium improved their scores when the time constraints were known in advance. No such adaptation was found on screen regardless of the medium preference. Beyond that, paper learning was more efficient and self-assessments of knowledge were better calibrated under most conditions. The results reinforce the inferiority of self-regulation of learning on screen and argue against technology-related factors as the main reason for this.  相似文献   

2.

Visually impaired individuals often rely on assistive technologies such as white canes for independent navigation. Many electronic enhancements to the traditional white cane have been proposed. However, only a few of these proof-of-concept technologies have been tested with authentic users, as most studies rely on blindfolded non-visually impaired participants or no testing with participants at all. Experiments involving blind users are usually not contrasted with the traditional white cane. This study set out to compare an ultrasound-based electronic cane with a traditional white cane. Moreover, we also compared the performance of a group of visually impaired participants (N = 10) with a group of blindfolded participants without visual impairments (N = 31). The results show that walking speed with the electronic cane is significantly slower compared to the traditional white cane. Moreover, the results show that the performance of the participants without visual impairments is significantly slower than for the visually impaired participants. No significant differences in obstacle detection rates were observed across participant groups and device types for obstacles on the ground, while 79% of the hanging obstacles were detected by the electronic cane. The results of this study thus suggest that electronic canes present only one advantage over the traditional cane, namely in its ability to detect hanging obstacles, at least without prolonged practice. Next, blindfolded participants are insufficient substitutes for blind participants who are expert cane users. The implication of this study is that research into digital white cane enhancements should include blind participants. These participants should be followed over time in longitudinal experiments to document if practice will lead to improvements that surpass the performance achieved with traditional canes.

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3.
Ontologies are becoming increasingly important in a variety of different fields, such as intelligent searching on the web, knowledge sharing and reuse, knowledge management, etc. Therefore, we expect that the need for tools to support the construction of ontologies will increase significantly in the coming years. In this paper, we investigate several of these tools. We evaluate the tools using two different ontologies: a simple one about university employees, and a second, more complex one, about the structure of a university study. The evaluation was conducted using a framework, which incorporates aspects of ontology buildings and testing, as well as cooperation with other users. Our conclusions are that the usefulness of the tools depends on the level of the users and the stage of development of the ontology.  相似文献   

4.
Evaluating e-learning systems is a complex activity which requires considerations of several criteria addressing quality in use as well as educational quality. Heuristic evaluation is a widespread method for usability evaluation, yet its output is often prone to subjective variability, primarily due to the generality of many heuristics. This paper presents the pattern-based (PB) inspection, which aims at reducing this drawback by exploiting a set of evaluation patterns to systematically drive inspectors in their evaluation activities. The application of PB inspection to the evaluation of e-learning systems is reported in this paper together with a study that compares this method to heuristic evaluation and user testing. The study involved 73 novice evaluators and 25 end users, who evaluated an e-learning application using one of the three techniques. The comparison metric was defined along six major dimensions, covering concepts of classical test theory and pragmatic aspects of usability evaluation. The study showed that evaluation patterns, capitalizing on the reuse of expert evaluators know-how, provide a systematic framework which reduces reliance on individual skills, increases inter-rater reliability and output standardization, permits the discovery of a larger set of different problems and decreases evaluation cost. Results also indicated that evaluation in general is strongly dependent on the methodological apparatus as well as on judgement bias and individual preferences of evaluators, providing support to the conceptualisation of interactive quality as a subjective judgement, recently brought forward by the UX research agenda.  相似文献   

5.
The involvement of Meta-heuristic algorithms in robot motion planning has attracted the attention of researchers in the robotics community due to the simplicity of the approaches and their effectiveness in the coordination of the agents. This study explores the implementation of many meta-heuristic algorithms, e.g. Genetic Algorithm (GA), Differential Evolution (DE), Particle Swarm Optimization (PSO) and Cuckoo Search Algorithm (CSA) in multiple motion planning scenarios. The study provides comparison between multiple meta-heuristic approaches against a set of well-known conventional motion planning and navigation techniques such as Dijkstra’s Algorithm (DA), Probabilistic Road Map (PRM), Rapidly Random Tree (RRT) and Potential Field (PF). Two experimental environments with difficult to manipulate layouts are used to examine the feasibility of the methods listed. several performance measures such as total travel time, number of collisions, travel distances, energy consumption and displacement errors are considered for assessing feasibility of the motion planning algorithms considered in the study. The results show the competitiveness of meta-heuristic approaches against conventional methods. Dijkstra ’s Algorithm (DA) is considered a benchmark solution and Constricted Particle Swarm Optimization (CPSO) is found performing better than other meta-heuristic approaches in unknown environments.  相似文献   

6.
Agent-based models (ABMs) are increasingly recognized as valuable tools in modelling human-environmental systems, but challenges and critics remain. One pressing challenge in the era of “Big Data” and given the flexibility of representation afforded by ABMs, is identifying the appropriate level of complicatedness in model structure for representing and investigating complex real-world systems. In this paper, we differentiate the concepts of complexity (model behaviour) and complicatedness (model structure), and illustrate the non-linear relationship between them. We then systematically evaluate the trade-offs between simple (often theoretical) models and complicated (often empirically-grounded) models. We propose using pattern-oriented modelling, stepwise approaches, and modular design to guide modellers in reaching an appropriate level of model complicatedness. While ABMs should be constructed as simple as possible but as complicated as necessary to address the predefined research questions, we also warn modellers of the pitfalls and risks of building “mid-level” models mixing stylized and empirical components.  相似文献   

7.
ABSTRACT

In the age of information revolution, information and communication technologies are penetrating all levels of societies and are also influencing the political aspect of each country by providing some facilities such as the Internet and web technologies. Democracy, as a universal value and a political system, is also well known and has an important role in the sublimation of the human societies. This study attempts to examine the effect of Internet extension on democracy promotion by using a panel consisting of 122 countries covering the period from the year 2000 to 2014. In order to estimate the effect, and also to deal with the endogeneity and autocorrelation problems, the dynamic panel data models are employed in the study. The results of estimation models indicate that Internet extension has a significantly positive effect on democracy promotion during the period. In the end, some ideas for further research are presented.  相似文献   

8.
Digital competences amongst the younger generations and the role of schools faced with the spread of new youth practices are topics of increasing interest. Some commentators state that, thanks to the intensive use of digital media, young people are developing significant competences that also correspond to important cognitive processes and new learning styles. However, other authors emphasize that there is no evidence about the positive impact of new technological practices on the development of significant cognitive abilities.In this paper we present a research study carried out in Italian schools on adolescents’ (aged 14-16) digital competence. On the basis of a preliminary theoretical model, a digital competence questionnaire was formulated and subsequently administered to a sample of secondary school students.The aim was to verify whether adolescents’ digital skills are limited to simple technical aspects or expand beyond them including a range of more significant knowledge and skills related to a conceptual understanding of technology, socio-relational knowledge and high-order cognitive skills. Like other studies, this research shows that when attention is shifted from strictly technical aspects to critical cognitive and socio-ethical dimensions involved in the use of technologies, students’ knowledge and competences result inadequate. The authors conclude that the optimistic portrayal of younger generations’ digital competences is poorly founded. Furthermore, it is pointed out that understanding students’ digital competence levels through fast assessment tools is a fundamental opportunity for schools to analyse deficiencies and prepare adequate intervention strategies.  相似文献   

9.
Nowadays, multi-core processor is the main technology used in desktop PCs, laptop computers and mobile hardware platforms. As the number of cores on a chip keeps increasing, it adds up the complexity and impacts more on both power and performance of a processor. In multi-processors, the number of cores and various parameters, such as issue-width, number of instructions and execution time, are key design factors to balance the amount of thread-level parallelism and instruction-level parallelism. In this paper, we perform a comprehensive simulation study that aims to find the optimum number of processor cores in desktop/laptop computing processor models with shallow pipeline depth. This paper also explores the trade-off between the number of cores and different parameters used in multi-processors in terms of power–performance gains and analyzes the impact of 3D stacking on the design of simultaneous multi-threading and chip multiprocessing. Our analysis shows that the optimum number of cores varies with different classes of workloads, namely: SPEC2000, SPEC2006 and MiBench. Simulation study is presented using architectures with shorter pipeline depth, showing that (1) the optimum number of cores for power–performance is 8, (2) the optimum number of threads in the range [2, 4], and (3) for beyond 32 cores, multi-core processors are no longer efficient in terms of performance benefits and overall power consumption.  相似文献   

10.
Many full truckload pick-up and delivery problems in the intermodal freight container transport industry can be modeled as Asymmetric Traveling Salesman Problems (ATSPs). Several authors have noted that while ATSPs are NP-hard, some instances are readily solved to optimality in only a short amount of time. Furthermore, the literature contains several references to the Stacker Crane Problem (SCP) as an “easy” problem amidst the ATSPs. We put this hypothesis to test by using statistical methods to build a model relating measurable distance matrix structures to the amount of time required by two existing exact solvers in finding solutions to over 500 ATSP instances. From this analysis we conclude that SCPs are not necessarily easier than other ATSPs, but a special subset of SCPs, termed drayage problems, are more readily solved. We speculate that drayage problems are “easy” because of a comparatively high number of zeros in symmetric locations within the distance matrix. In real-world drayage problems (i.e. the movement of containers a short distance to/from a port or rail terminal), these zeros correspond to the prevalence of jobs originating at or destined to a fixed number of freight terminals.  相似文献   

11.
Dear editor, Implementation attacks such as fault attack(FA)[1]and side-channel analysis (SCA)[2]are signifi-cant threats to the cryptographic device security.I...  相似文献   

12.
Process-based forest ecosystem models vary from simple physiological, complex physiological, to hybrid empirical-physiological models. Previous studies indicate that complex models provide the best prediction at plot scale with a temporal extent of less than 10 years, however, it is largely untested as to whether complex models outperform the other two types of models at plot and regional scale in longer timeframe (i.e. decades). We compared model predictions of aboveground carbon by one representative model of each model type (PnET-II, ED2 and LINKAGES v2.2, respectively) with field data (19–77 years) at both scales in the Central Hardwood Forests of the United States. At plot scale, predictions by complex physiological model were the most concordant with field data, suggesting that physiological processes are more influential than forest composition and structure. Hybrid model provided the best predictions at regional scale, suggesting that forest composition and structure may be more influential than physiological processes.  相似文献   

13.
Multimodal fusion is a complex topic. For surveillance applications audio–visual fusion is very promising given the complementary nature of the two streams. However, drawing the correct conclusion from multi-sensor data is not straightforward. In previous work we have analysed a database with audio–visual recordings of unwanted behavior in trains (Lefter et al., 2012) and focused on a limited subset of the recorded data. We have collected multi- and unimodal assessments by humans, who have given aggression scores on a 3 point scale. We showed that there are no trivial fusion algorithms to predict the multimodal labels from the unimodal labels since part of the information is lost when using the unimodal streams. We proposed an intermediate step to discover the structure in the fusion process. This step is based upon meta-features and we find a set of five which have an impact on the fusion process. In this paper we extend the findings in (Lefter et al., 2012) for the general case using the entire database. We prove that the meta-features have a positive effect on the fusion process in terms of labels. We then compare three fusion methods that encapsulate the meta-features. They are based on automatic prediction of the intermediate level variables and multimodal aggression from state of the art low level acoustic, linguistic and visual features. The first fusion method is based on applying multiple classifiers to predict intermediate level features from the low level features, and to predict the multimodal label from the intermediate variables. The other two approaches are based on probabilistic graphical models, one using (Dynamic) Bayesian Networks and the other one using Conditional Random Fields. We learn that each approach has its strengths and weaknesses in predicting specific aggression classes and using the meta-features yields significant improvements in all cases.  相似文献   

14.
One of the main problems of today’s ubiquitous computing systems is that they do not meet their quality requirements. Ubiquitous computing services such as mobile data services (MDS) are fundamentally different from traditional information systems (IS) in terms of important quality factors such as information or system quality because it has been used in various life contexts. We identify important quality factors on various contexts in Korea MDS market. Using the results of qualitative study, we propose research model. To identify the effect of motivational orientation type on users’ behavior, we classified users according to their propensities into intrinsic and extrinsic motivational orientation groups. The results show that the impact of quality factors on user satisfaction is differentiated depending on motivational orientation types. The paper concludes with a discussion of the study’s limitations and implications.  相似文献   

15.
Stable dispersions of micro and nanosized Al2O3 particles in ethylene glycol are prepared with the aid of sonication. The temperature dependant acoustic properties such as ultrasonic velocity, adiabatic compressibility, attenuation and acoustic impedance are studied and reported in this paper. In microfluids the particle–fluid interaction is observed to decrease with increase of concentration of particles whereas in nanofluids it is observed to increase up to the critical concentration (0.6 Wt%) and above which the particle–particle interaction dominates due to agglomeration of particles. A range of concentration with significant particle–fluid interaction is identified for effective nanofluid applications.  相似文献   

16.
Social broadcasting services, such as Twitter and YouTube, are revolutionizing the way we access information and publish our own content. What is the key innovation of such services? We argue that the key innovation of social broadcasting services is recognizing and connecting people’s need for information and attention. While the value of information is widely studied, the importance of attention is less well understood. We use a collection of nearly 3 million Twitter user profiles to study the cross-sectional characteristics of user behavior; we also monitor 521 active Twitter users over a period of 282 days to carry out time-series analyses and a panel data analysis of user behavior. The empirical results consistently suggest that people’s search for attention is an important motivation for them to contribute content on Twitter. This finding supports our conceptual view of social broadcasting services as innovative platforms connecting people’s need for information and attention. It also has important implications for practitioners in this booming field.  相似文献   

17.
Small businesses often suffer from a lack of resources, which in many cases they cite as a reason why they cannot prepare for crises. Increasingly frequent threats may have forced them to rethink their thinking. The aim of this study is to compare data from 2009, 2012, 2019 and 2021 and thus provide the basis for the non/confirmation of the hypothesis of continuously increasing crisis preparedness in small enterprises. A questionnaire survey was conducted within Czech small businesses in the mentioned years. More than 1000 respondents participated in the research each year. The outputs were statistically processed. Different prevention approach strategies in each year, barriers that complicate preparation and understanding of the not/importance of prevention have been identified. A basic hypothesis could not be confirmed. However, in the context of how highly the importance of crisis preparedness is assessed, actual active prevention is still low. Managers still do not consider crisis preparedness to be part of their competitiveness. The practical benefit of the research is to initiate their reflection on the necessity of crisis prevention. Theoretical contribution is its comparative character over time, allowing to monitor the evolution of the approach of small business managers.  相似文献   

18.
Social networking sites (SNSs) are important tools for college students to maintain and develop social capital. Yet, few studies on the social implications of using SNSs have focused on international students and their use of different social media platforms for social capital. This study aims to fill this gap by examining the implications of using host country and home country SNSs for social capital among Chinese international students in the United States. A survey of Chinese international students at a large public university (N = 210) reveals that both Facebook and Renren use are positively associated with bridging social capital but not with bonding social capital. Facebook use has a stronger relationship with bridging social capital than does Renren use. Yet, only Renren use has a significant and positive relationship with maintaining home country social capital. These results have practical implications for international students to develop different types of social capital through different social media platforms.  相似文献   

19.
OBJECTIVE: To test whether feedback and discussion of ergonomic and psychosocial working environment data during 1 short session with individual, groups, or supervisors of VDU workers had effects on (1) the quality of implemented modifications in workplace design, working technique, or psychosocial aspects; (2) psychological demands, decision latitude, and social support; (3) comfort during computer work, emotional stress, and prevalence of musculoskeletal symptoms or eye discomfort. METHODS: Thirty-six workgroups from 9 organizations were randomized to 3 feedback conditions (individual, workgroup, supervisor) or control. Follow-up was 6 months after intervention. Questionnaire data aggregated on the workgroup level were used. RESULTS: Effect (positive) on social support was indicated from feedback to supervisors. Conclusion: Feedback and discussion of ergonomic and psychosocial working environment data with supervisors of white-collar VDU workers may have positive effect on social support measured as a group characteristic. Sources of potential bias are discussed.  相似文献   

20.
The objective of this study was to determine the quality of MEDLINE searches done by physicians, physician trainees, and expert searchers (clinicians and librarians). Its design was an analytic survey with independent replication in a setting of self-service online searching from medical wards, an intensive care unit, a coronary care unit, an emergency room, and an ambulatory clinic in a 300-bed teaching hospital. Participating were all M.D. clinical clerks, house, and attending staff responsible for patients in the above settings. Intervention for all participants consisted of a 2-h small group class and 1-h practice session on MEDLINE searching (GRATEFUL MED) before free access to MEDLINE. Search questions from 104 randomly selected novice searches were given to 1 of 13 clinicians with prior search experience and 1 of 3 librarians to run independent searches (triplicated searches). Measurements and main results from these unique citations of the triplicated searches were sent to expert clinicians to rate for relevance (7-point scale). Recall (number of relevant citations retrieved from an individual search divided by the total number of relevant citations from all searches on the same topic) and precision (proportion of relevant citations retrieved in each search) were calculated. Librarians were significantly better than novices for both. Librarians had equivalent recall to, and better precision than, experienced end-users. Unexpectedly, only 20% of relevant citations were retrieved by more than one search of the set of three, with the conclusion that novice searchers on MEDLINE via GRATEFUL MED after brief training have relatively low recall and precision. Recall improves with experience but precision remains suboptimal. Further research is needed to determine the "learning curve," evaluate training interventions, and explore the non-overlapping retrieval of relevant citations by different searchers.  相似文献   

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