Can movement parallax compensate lacking stereopsis in spatial explorative search tasks?

In an explorative task subjects were asked to track a line presented in combination with other confusing lines on a 3D display. 24 subjects performed the explorative task under three depth cue conditions which were: stereopsis, movement parallax or a combination of stereopsis and movement parallax (stereo and parallax).

Task performance was assessed by recording completion time and correctness of answer.

The combination of stereopsis and movement parallax gave rise to highest percentage of correct answers (84%), followed by the condition where movement parallax was the only depth cue (80%). Percentage of correct answers in both conditions was found to be significantly higher than it was in the condition with stereopsis (60%).

Mean completion time was about the same in the stereo and parallax condition and the stereopsis condition. Compared to the movement parallax condition both means were significantly decreased.

Accuracy in completing the task was found to be similar in 3D displays enabling movement parallax and in 3D displays presenting stereoscopic images.     

Can quantum entanglement detection schemes improve search?

Quantum computation, in particular Grover’s algorithm, has aroused a great deal of interest since it allows for a quadratic speed-up to be obtained in search procedures. Classical search procedures for an N element database require at most O(N) time complexity. Grover’s algorithm is able to find a solution with high probability in ){O(\sqrt{N})} time through an amplitude amplification scheme. In this work we draw elements from both classical and quantum computation to develop an alternative search proposal based on quantum entanglement detection schemes. In 2002, Horodecki and Ekert proposed an efficient method for direct detection of quantum entanglement. Our proposition to quantum search combines quantum entanglement detection alongside entanglement inducing operators. The quantum search algorithm relies on measuring a quantum superposition after having applied a unitary evolution. We deviate from the standard method by focusing on fine-tuning a unitary operator in order to infer the solution with certainty. Our proposal sacrifices space for speed and depends on the mathematical properties of linear positive maps Λ which have not been operationally characterized. Whether such a Λ can be easily determined remains an open question.     

Correction to: Can search result summaries enhance the web search efficiency and experiences of the visually impaired users?

There are limited studies that are addressing the challenges of visually impaired (VI) users when viewing search results on a search engine interface by using a screen reader. This study investigates the effect of providing an overview of search results to VI users. We present a novel interactive search engine interface called InteractSE to support VI users during the results exploration stage in order to improve their interactive experience and web search efficiency. An overview of the search results is generated using an unsupervised machine learning approach to present the discovered concepts via a formal concept analysis that is domain-independent. These concepts are arranged in a multi-level tree following a hierarchical order and covering all retrieved documents that share maximal features. The InteractSE interface was evaluated by 16 legally blind users and compared with the Google search engine interface for complex search tasks. The evaluation results were obtained based on both quantitative (as task completion time) and qualitative (as participants’ feedback) measures. These results are promising and indicate that InteractSE enhances the search efficiency and consequently advances user experience. Our observations and analysis of the user interactions and feedback yielded design suggestions to support VI users when exploring and interacting with search results.

     

How can multimodal cues from child-directed interaction reduce learning complexity in robots?

Robots have to deal with an enormous amount of sensory stimuli. One solution in making sense of them is to enable a robot system to actively search for cues that help structuring the information. Studies with infants reveal that parents support the learning-process by modifying their interaction style, dependent on their child's developmental age. In our study, in which parents demonstrated everyday actions to their preverbal children (8–11 months old), our aim was to identify objective parameters for multimodal action modification. Our results reveal two action parameters being modified in adult–child interaction: roundness and pace. Furthermore, we found that language has the power to help children structuring actions sequences by synchrony and emphasis. These insights are discussed with respect to the built-in attention architecture of a socially interactive robot, which enables it to understand demonstrated actions. Our algorithmic approach towards automatically detecting the task structure in child-designed input demonstrates the potential impact of insights from developmental learning on robotics. The presented findings pave the way to automatically detect when to imitate in a demonstration task.     

Encoding search trees in lists †

We study the optimal encoding of search trees in lists and, in particular, in single-linked lists. We are able to provide an 0(n²) construction algorithm for weighted binary search trees, which can be generalized to give an 0(n² log m) algorithm for weighted m-ary search trees.     

Raters’ reliability in clone benchmarks construction

Cloned code often complicates code maintenance and evolution and must therefore be effectively detected. One of the biggest challenges for clone detectors is to reduce the amount of irrelevant clones they found, called false positives. Several benchmarks of true and false positive clones have been introduced, enabling tool developers to compare, assess and fine-tune their tools. Manual inspection of clone candidates is performed by raters that do not have expertise on the underlying code. This way of building benchmarks might be unreliable when considering context-dependent clones i.e., clones valid for a specific purpose. Our goal is to investigate the reliability of rater judgments about context-dependent clones. We randomly select about 600 clones from two projects and ask several raters, including experts of the projects, to manually classify these clones. We observe that judgments of non expert raters are not always repeatable. We also observe that they seldomly agree with each others and with the expert. Finally, we find that the project and the fact that a clone is a true or false positive might have an influence on the agreement between the expert and non experts. Therefore, using non experts to produce clone benchmarks could be unreliable.     

Can a short nap and bright light function as implicit learning and visual search enhancers?

The present study examined effects of a short nap (20 min) and/or bright light (2000 lux) on visual search and implicit learning in a contextual cueing task. Fifteen participants performed a contextual cueing task twice a day (1200–1330 h and 1430–1600 h) and scored subjective sleepiness before and after a short afternoon nap or a break period. Participants served a total of four experimental conditions (control, short nap, bright light and short nap with bright light). During the second task, bright light treatment (BLT) was applied in the two of the four conditions. Participants performed both tasks in a dimly lit environment except during the light treatment. Results showed that a short nap reduced subjective sleepiness and improved visual search time, but it did not affect implicit learning. Bright light reduced subjective sleepiness. A short nap in the afternoon could be a countermeasure against sleepiness and an enhancer for visual search.

Practitioner Summary: The study examined effects of a short afternoon nap (20 min) and/or bright light (2000 lux) on visual search and implicit learning. A short nap is a powerful countermeasure against sleepiness compared to bright light exposure in the afternoon.     

Is visual content in textual search interfaces beneficial to dyslexic users?

Dyslexia is a learning disability characterised by problems with accurate or fluent word recognition, poor decoding, and poor spelling abilities. Although several studies have addressed dyslexia and Web accessibility, less is known about how dyslexia affects information search. This study investigated whether the inclusion of icons in search user interfaces enhances performance among dyslexics. A total of 21 dyslexics and 21 controls completed 52 search tasks in 4 conditions: icons only, words only, and both icons and words in a grid layout and a list layout, while eye movements were recorded. Dyslexics took significantly longer than controls to locate targets in tasks containing text, but not in the icon-only condition. Dyslexics had longer fixation durations than controls in both icon and text based search arrays, suggesting higher mental load associated with search tasks generally. The addition of words to icon arrays led to faster search times within controls, but not dyslexics. Dyslexics also exhibited more fixations on dual-modality tasks, and longer scanpaths than controls in list layout. Both groups were fastest searching the list layout, with icons and words listed in columns. Results are discussed in terms of the design of accessible search interfaces for dyslexic users, taking into account mental load of dual-modality information display, and the arrangement of search items. Empirical data is provided for the design of accessible search results interfaces for dyslexics.     

Why did you pick that? Visualising relevance criteria in exploratory search

In this article, we present a set of approaches in analysing data gathered during experimentation with exploratory search systems and users’ acts of judging the relevance of the information retrieved by the system. We present three tools for quantitatively analysing encoded qualitative data: relevance-criteria profile, relevance-judgement complexity and session visualisation. Relevance-criteria profiles capture the prominence of each criterion usage with respect to the search sessions of individuals or selected user groups (e.g. groups defined by the users affiliations and/or level of research experience). Relevance-judgement complexity, on the other hand, reflects the number of criteria involved in a single judgment process. Finally, session visualisation brings these results together in a sequential representation of criteria usage and relevance judgements throughout a session, potentially allowing the researcher to quickly detect emerging patterns with respect to interactions, relevance criteria usage and complexity. The use of these tools is demonstrated using results from a pilot-user study that was conducted at the Robert Gordon University in 2008. We conclude by highlighting how these tools might be used to support the improvement of end-user services in digital libraries.     

Are hospitals becoming high reliability organizations?

High Reliability Organizations (HROs) are complex systems in which many accidents and adverse events that could occur within those systems or at the interfaces with other systems are actually avoided or prevented. Many organizations in high-risk industries have successfully implemented HRO approaches. In recent years, initiatives have been undertaken aimed at transforming hospitals into HROs. Actually, despite some improvements, these initiatives have not shown the expected results. In this paper, we discuss the possible reasons for such outcomes. We will show that, when compared with traditional HROs, hospitals are undoubtedly high-risk organizations, but have specificities and experience systemic socio-organizational barriers that make them difficult to transform into HROs.     

Can small shifts in circadian phase affect performance?

Small shifts in circadian timing occur frequently as a result of daylight saving time or later weekend sleep. These subtle shifts in circadian phase have been shown to influence subjective sleepiness, but it remains unclear if they can significantly affect performance. In a retrospective analysis we examined performance on the Psychomotor Vigilance Test before bedtime and after wake time in 11 healthy adults on fixed sleep schedules based on their habitual sleep times. The dim light melatonin onset, a marker of circadian timing, was measured on two occasions. An average 1.1?h shift away from a proposed optimal circadian phase angle (6?h between melatonin onset and midpoint of sleep) significantly slowed mean, median and fastest 10% reaction times before bedtime and after wake time (p?相似文献   

Theoretical results in genetic programming: the next ten years?

We consider the theoretical results in GP so far and prospective areas for the future. We begin by reviewing the state of the art in genetic programming (GP) theory including: schema theories, Markov chain models, the distribution of functionality in program search spaces, the problem of bloat, the applicability of the no-free-lunch theory to GP, and how we can estimate the difficulty of problems before actually running the system. We then look at how each of these areas might develop in the next decade, considering also new possible avenues for theory, the challenges ahead and the open issues.     

Information search and paid results — proposition and test of a hierarchy-of-effect model

Search engines stand as the first entry point to internet resources for 70% of users. The results page is therefore an appealing place for advertising in the form of sponsored links also called paid results. Yet little academic knowledge has been developed to understand users’ perceptions and behaviors toward sponsored links. In particular it is of foremost importance to delineate factors that influence click intention and behavior. This paper proposes a hierarchy-of-effects model in order to understand surfers’ click on sponsored links. An empirical study is conducted over 349 participants confronted to three different Search Engine Result Pages (SERP) representing three search situations. Results indicate a significant relationship between attitude toward sponsored links and behavioral intention. In addition, past satisfaction is found to significantly predict click behavior. The contribution of this study for both researchers and practitioners is discussed.     

Is paid search overrated? When bricks-and-mortar-only retailers should not use paid search

While bricks-and-mortar-only retailers do not offer online purchasing, they often take advantage of multi-channel management strategies to reach consumers in a pre-purchase phase. We investigate whether paid search can increase the sales of brick-and-mortar retailers who promote their offers via an informational website. Although a sizeable one third of all retailers still trade without an online-shop, previous work has been silent about the effects of paid search for them. We make use of a randomized field experiment and an end-to-end tracking mechanism to investigate the cross-channel behavior of individual consumers. Our empirical results suggest that, whilst paid search increases the number of potential customers through enhancing the reach of marketing initiatives, store sales are not increased. We conclude that customers who search online to buy offline primarily use paid search as a navigational shortcut to the retailer’s website. Consequently, bricks-and-mortar-only retailers seeking to increase store purchases should approach paid search with caution.     

Can quantum discord increase in a quantum communication task?

Quantum teleportation of an unknown quantum state is one of the few communication tasks which has no classical counterpart. Usually the aim of teleportation is to send an unknown quantum state to a receiver. But is it possible in some way that the receiver’s state has more quantum discord than the sender’s state? We look at a scenario where Alice and Bob share a pure quantum state and Alice has an unknown quantum state. She performs joint measurement on her qubits and channel to prepare Bob’s qubits in a mixed state which has higher quantum discord than hers. We also observe an interesting feature in this scenario, when the quantum discord of Alice’s qubits increases, then the quantum discord of Bob’s prepared qubits decreases. Furthermore, we show that the fidelity of one-qubit quantum teleportation using Bob’s prepared qubits as the channel is higher than using Alice’s qubits.     

Which social elements are visible in virtual groups? Addressing the categorization of social expressions

Learning is a social process. That is why it is extremely important to understand how students interact socially in online courses and how it affects the learning process. However, social aspects, understood as those expressions or comments that go beyond strictly academic interaction, i.e. the need to carry out group work, are not clearly defined. Researchers have proposed different models of categories to observe or measure social aspects. This paper contributes to this field through addressing the categorization of social expression in online groups through a qualitative research procedure. Specifically, 19 indicators have been identified and organized into 4 categories: formal, attitudinal, emotional and informal. The findings suggest that those indicators related to formal and attitudinal aspects appear more often than emotional and informal ones. Different profiles (Psychology or Computer Engineering) as well as different levels of experience in online learning (beginners or experts) have also been analyzed, concluding that Psychology students turn to social expressions more often than Computer Engineering ones. As students progress in their undergraduate studies, social expressions are perceived and used to the extent that they ease the learning process.     

Can thioglycosides imitate the oxonium intermediate in glycosyl hydrolases?

Glycosyl hydrolases catalyse the acid hydrolysis of the glycosidic bond of glycans. The structure of barley beta-D-glucan glucohydrolase in complex with a thiol substrate analogue presents very short contacts between the carboxyl oxygen atoms of the catalytic acid and the sulphur atom of the inhibitor. The geometries of acetic acid and dimethylsulfide in various ionisation states from ab initio molecular orbital calculations predict similar short contacts when an acetate anion forms a complex with a sulphonium cation. The energy of this complex is, however, significantly greater than the energy of the complex where both acetic acid and dimethylsulfide are neutral. Calculations on an active site model of barley beta-D-glucan glucohydrolase indicate that the protein environment is able to significantly reduce this energy. The energy required for mechanical constraint of the short S...O separations, however, is identical to that required for the transfer of the proton from the acid to the sulphur. The identity of the species participating in the short contacts remains unanswered.     

When Can Limited Randomness Be Used in Repeated Games?

The central result of classical game theory states that every finite normal form game has a Nash equilibrium, provided that players are allowed to use randomized (mixed) strategies. However, in practice, humans are known to be bad at generating random-like sequences, and true random bits may be unavailable. Even if the players have access to enough random bits for a single instance of the game their randomness might be insufficient if the game is played many times. In this work, we ask whether randomness is necessary for equilibria to exist in finitely repeated games. We show that for a large class of games containing arbitrary two-player zero-sum games, approximate Nash equilibria of the n-stage repeated version of the game exist if and only if both players have Ω(n) random bits. In contrast, we show that there exists a class of games for which no equilibrium exists in pure strategies, yet the n-stage repeated version of the game has an exact Nash equilibrium in which each player uses only a constant number of random bits. When the players are assumed to be computationally bounded, if cryptographic pseudorandom generators (or, equivalently, one-way functions) exist, then the players can base their strategies on “random-like” sequences derived from only a small number of truly random bits. We show that, in contrast, in repeated two-player zero-sum games, if pseudorandom generators do not exist, then Ω(n) random bits remain necessary for equilibria to exist.