Searching Tasks Research Articles

State-Transform MPC-SMC-Based Trajectory Tracking Control of Cross-Rudder AUV Carrying Out Underwater Searching Tasks

Abstract: In this study, we present a novel dual-loop robust trajectory tracking framework for autonomous underwater vehicles, with the objective of enhancing their performance in underwater searching tasks amidst oceanic disturbances. Initially, a real-world AUV experiment is conducted to validate the efficacy of a cross-rudder AUV configuration in maintaining sailing angle stability during the diving stage, which exhibits a strong capability for straight-line sailing. Building upon the experimental findings, we introduce a state-transform-model predictive guide law to compute the desired velocity for the dynamics loop. This guide law dynamically adjusts the controller across varying depths, thereby reducing model predictive control (MPC) computation while optimizing timing without compromising precision or convergence speed. Subsequently, we incorporate a sliding mode controller with a prescribed disturbance observer into the velocity control loop to concurrently enhance the robustness and convergence rate of the system. This innovative amalgamation of controllers significantly improves tracking precision and convergence rate, while also alleviating the computational burden—a pervasive challenge in AUV MPC control. Finally, various condition simulations are conducted to validate the robustness, effectiveness, and superiority of the proposed method. These simulations underscore the enhanced performance and reliability of our proposed trajectory tracking framework, highlighting its potential utility in real-world AUV applications.

Examining Eye Tracking Metrics and Cognitive Function in Post-Stroke Individuals: A Comparison of Visual Searching Tasks between Those with and without Cognitive Impairment

Introduction: After a stroke, individuals commonly experience visual problems and impaired cognitive function, which can significantly impact their daily lives. In addition to visual neglect and hemianopia, stroke survivors often have difficulties with visual search tasks. Researchers are increasingly interested in using eye tracking technology to study cognitive processing and determine whether eye tracking metrics can be used to screen and assess cognitive impairment in patients with neurological disorders. As such, assessing these areas and understanding their relationship is crucial for effective stroke rehabilitation. Methods: We enrolled 60 stroke patients in this study and evaluated their eye tracking performance and cognitive function through a series of tests. Subsequently, we divided the subjects into two groups based on their scores on the HK-MoCA test, with scores below 21 out of 30 indicating cognitive impairment. We then compared the eye tracking metrics between the two groups and identified any significant differences that existed. Spearman correlation analysis was conducted to explore the relationship between clinical test scores and eye tracking metrics. Moreover, we employed a Mann-Whitney U test to compare eye tracking metrics between groups with and without cognitive impairment. Results: Our results revealed significant correlations between various eye tracking metrics and cognitive tests (p ≤ 0.001–0.041). Furthermore, the group without cognitive impairment demonstrated higher saccade velocity, gaze path velocity, and shorter time to target than the group with cognitive impairment (p ≤ 0.001–0.040). Receiver operating characteristic curve analyses were performed, and the optimal cut-off values for gaze path velocity and saccade velocity were 329.665 (px/s) (sensitivity = 0.80, specificity = 0.533) and 2.150 (px/ms) (sensitivity = 0.733, specificity = 0.633), respectively. Conclusions: Our findings indicate a significant correlation between eye tracking metrics and cognitive test scores. Furthermore, the group with cognitive impairment exhibited a significant difference in these metrics, and a cut-off value was identified to predict whether a client was experiencing cognitive impairment.

Early Detection of Human Decision-Making in Concealed Object Visual Searching Tasks: An EEG-BiLSTM Study.

Detecting concealed objects presents a significant challenge for human and artificial intelligent systems. Detecting concealed objects task necessitates a high level of human attention and cognitive effort to complete the task successfully. Thus, in this study, we use concealed objects as stimuli for our decision-making experimental paradigms to quantify participants' decision-making performance. We applied a deep learning model, Bi-directional Long Short Term Memory (BiLSTM), to predict the participant's decision accuracy by using their electroencephalogram (EEG) signals as input. The classifier model demonstrated high accuracy, reaching 96.1% with an epoching time range of 500 ms following the stimulus event onset. The results revealed that the parietal-occipital brain region provides highly informative information for the classifier in the concealed visual searching tasks. Furthermore, the neural mechanism underlying the concealed visual-searching and decision-making process was explained by analyzing serial EEG components. The findings of this study could contribute to the development of a fault alert system, which has the potential to improve human decision-making performance.

Evolutionary Dynamics of Division of Labor Games for Underwater Searching Tasks

Division of labor in self-organized groups is a problem of both theoretical significance and application value. Many application problems in the real world require efficient task allocation. We propose a model combining bio-inspiration and evolutionary game theory. This research model theoretically analyzes the problem of target search in unknown areas for multi-robot systems. If the robot’s operating area is underwater, the problem becomes more complicated due to its information sharing restrictions. Additionally, it drives strategy updates and calculates the fixed probability of relevant strategies, using evolutionary game theory and the commonly used Fermi function. Our study estimates the fixed probability under arbitrary selection intensity and the fixed probability and time under weak selection for the two-player game model. In the multi-player game, we get these results for weak selection, which is conducive to the coexistence of the two strategies. Moreover, the conducted simulations confirm our analysis. These results help to understand and design effective mechanisms in which self-organizing collective dynamics appears in the form of maximizing the benefits of multi-agent systems in the case of the asymmetric game.

Exploring the Role of Distraction in Weak Flow–Performance Link Based on VR Searching Tasks

The weak association between flow experience and task performance (also known as weak flow-performance link) can reduce the positive effect of virtual reality (VR) applications. Distraction caused by incongruence between the primary task and interactive artifacts may be a direct factor leading to the weak link, but it has still not been tested. To empirically test this assumption and explore approaches to alleviate it, we developed the ‘VR searching paradigm’ and a prototype VR system, based on which three comparative experiments were conducted. Study 1 tested the effect of distraction and proved that high levels of distraction caused by incongruence can lead to the weak link (β = 0.198, p = 0.391). Next, two common design guidelines were proposed to deal with distraction. Study 2 tested the effect of reducing conspicuous but task-irrelevant distractors (guideline 1) on flow-performance link. Study 3 tested the effect of providing visual cues (utilizing distractors to achieve task-oriented selective attention), which is guideline 2, on flow-performance link. The results of studies 2 and 3 revealed that both guidelines helped enhance the task performance without damaging flow experience, alleviating the weak link problem (β = 0.351, p = 0.031; β = 0.255, p = 0.041). Our results provide the first piece of evidence that directly proves the effect of distraction on weak flow-performance link, which helps improve the explanation of the mechanism. Moreover, this paper is the first that proves the effectiveness of two easy approaches to alleviating the weak link by way of guiding the user’s task-relevant attention.

A COMPARATIVE RESEARCH ON G-HMM AND TSS TECHNOLOGIES FOR EYE MOVEMENT TRACKING ANALYSIS

Eye movement analysis provides a new way for disease screening, quantification and assessment. In order to track and analyze eye movement scanpaths under different conditions, this paper proposed the Gaussian mixture-Hidden Markov Model (G-HMM) modeling the eye movement scanpath during saccade, combing with the Time-Shifting Segmentation (TSS) method for model optimization, and also the Linear Discriminant Analysis (LDA) method was utilized to perform the recognition and evaluation tasks based on the multi-dimensional features. In the experiments, 800 real scene images of eye-movement sequences datasets were used, and the experimental results show that the G-HMM method has high specificity for free searching tasks and high sensitivity for prompt object search tasks, while TSS can strengthen the difference of eye movement characteristics, which is conducive to eye movement pattern recognition, especially for search tasks.

Exploration Enhanced RPSO for Collaborative Multitarget Searching of Robotic Swarms

Particle Swarm Optimization (PSO) is an excellent population-based optimization algorithm. Meanwhile, because of its inspiration source and the velocity update feature, it is also widely used in the collaborative searching tasks for swarm robotics. One of the PSO-based models for robotic swarm searching tasks is Robotic PSO (RPSO). It adds additional items for obstacle avoidance into standard PSO and has been applied to many single-target search tasks. However, due to PSO’s global optimization characteristics, it is easy to converge to a specific position in the search space and lose the ability to explore further. When faced with the problem of multitarget searching, it may become inefficient or even invalid. This paper proposes an Exploration Enhanced Robotic PSO (E2RPSO) method for multitarget searching problems for robotic swarms. The proposed method modifies the third item in the RPSO as an additional attraction term. This item not only enables the robot to avoid collisions but also guides the swarm to search unexplored regions as much as possible. This operation increases the swarm’s task-specific (top-down) diversity, making the system cover a broader search area and avoid falling into local optimums. Besides, the aggregation degree and evolution speed factors are also included in determining the inertia weight of the proposed method, which adjusts the swarm’s internal (bottom-up) diversity dynamically. The comparison results show that this method can balance the relationship between exploration and exploitation well, which has the potential to be applied to multitarget searching scenarios.

Autonomous Searching for a Diffusive Source Based on Minimizing the Combination of Entropy and Potential Energy.

The infotaxis scheme is a search strategy for a diffusive source, where the sensor platform is driven to reduce the uncertainty about the source through climbing the information gradient. The infotaxis scheme has been successfully applied in many source searching tasks and has demonstrated fast and stable searching capabilities. However, the infotaxis scheme focuses on gathering information to reduce the uncertainty down to zero, rather than chasing the most probable estimated source when a reliable estimation is obtained. This leads the sensor to spend more time exploring the space and yields a longer search path. In this paper, from the context of exploration-exploitation balance, a novel search scheme based on minimizing free energy that combines the entropy and the potential energy is proposed. The term entropy is implemented as the exploration to gather more information. The term potential energy, leveraging the distance to the estimated sources, is implemented as the exploitation to reinforce the chasing behavior with the receding of the uncertainty. It results in a faster effective search strategy by which the sensor determines its actions by minimizing the free energy rather than only the entropy in traditional infotaxis. Simulations of the source search task based on the computational plume verify the efficiency of the proposed strategy, achieving a shorter mean search time.

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Planning of any military activities, including reconnaissance and retrieval activities of the National Guard of Ukraine (NGU) formations, involves knowledge of the capabilities of actors. In the case of reconnaissance, we are talking about intelligence, surveillance and reconnaissance groups (ISRGs) which may include regular reconnaissance units or temporary ones designed to perform specific tasks. The process of forming such temporary groups requires knowledge of certain capabilities of the personnel. This is especially important the planning of search activities in the direction by the relay mode. When planning a search this way it is convenient to use the empirical models of ISRGs. They can be developed on the basis of the data on the capabilities of the individual servicemen of the corresponding units, for example, intelligence teams of Special Forces operational detachments, as well as individual detachments of the Special Forces of the NGU, to perform searching tasks. The development of the mentioned empirical model involves knowledge of the capabilities of servicemen to search one or another mode of search a certain combat order specific conditions. Such information can be obtained during the implementation of real military-combat tasks or field studies and exercises. The compilation of empirical models based on such knowledge is today a definite problem. For the first time, the attention was drawn to the need to create an empirical ISRG model for conducting the relay search during the field studies that were conducted October 2006. During this field event, the relay search was conducted by two search (relay) teams. The teams were formed from regular reconnaissance battalions of the special purpose of the designated unit. Studies have identified the disadvantages of this approach. In regular reconnaissance groups, the ability of an individual intelligence officer to perform search tasks differed significantly. The search rate was determined by a weaker one. This disadvantage was taken into account during a tactical training that was held mountainous areas May 2008. A part of this study, devoted to the development of research issues of relay search, revealed the benefits of completing search teams not on the basis of regular reconnaissance groups, but on the principle of creating temporary teams of soldiers of equal opportunity. The latest field trials, conducted 2017-2019 identified the need for teams to be formed on the basis of special empirical data of individual servicemen. It is expedient to describe such temporary search teams the form of empirical models of ISRGs of various search capabilities. This greatly simplifies the process of designing a relay search, first of all, the distribution of the route for the search stages and the definition of the search must a mental analogue of the ISRG is considered, which is formed from the personnel of a specific intelligence unit or a special-purpose unit of the NGU capable of solving search tasks given regimes and combat orders. This model should reflect the search capabilities of the formed ISRG through verbal, logical, graphical, graph-analytic or mathematical description. In excess of the time during which the personnel is able to withstand the given power of physical activity, the capabilities of personnel is significantly reduced. As a rule, this significant decrease is accompanied by a sharp drop the indicators of special capabilities of the personnel, first of all, the rational decision-making ability, as well as other, such as visual and operational memory, sometimes physiological response to extreme situations. The ability to make a rational decision is evaluated by the degree of implementation of a systematic approach to solving one or another test tactical task associated with the legend of the search. The evaluation is carried out by using reference responses, which are developed as unambiguous answers to each tactical task. The given characteristics must form the basis of passports-forms, which are expedient to create for temporary ISRGs, suitable for performing search tasks with the given level of loading and acceptable ability to solve certain tactical tasks.

Web users with autism: eye tracking evidence for differences

ABSTRACTAnecdotal evidence suggests that people with autism may have different processing strategies when accessing the web. However, limited empirical evidence is available to support this. This paper presents an eye tracking study with 18 participants with high-functioning autism and 18 neurotypical participants to investigate the similarities and differences between these two groups in terms of how they search for information within web pages. According to our analysis, people with autism are likely to be less successful in completing their searching tasks. They also have a tendency to look at more elements on web pages and make more transitions between the elements in comparison to neurotypical people. In addition, they tend to make shorter but more frequent fixations on elements which are not directly related to a given search task. Therefore, this paper presents the first empirical study to investigate how people with autism differ from neurotypical people when they search for information within web pages based on an in-depth statistical analysis of their gaze patterns.

Defining and seeking to identify critical Internet literacy: a discourse analysis of fifth‐graders' Internet search and evaluation activity

AbstractPedagogic focus is shifting increasingly from teaching students to search the Internet efficiently to encouraging critical Internet literacy, but this paper argues that these more complex and subtle skills are both challenging to teach and difficult to identify. The paper presents an analysis of the discourse of triads of fifth graders undertaking an Internet search task that emphasised decisions relating to the trustworthiness and relevance of websites. The analysis uses two lenses – the Vygotskian concept ofobuchenieand Mercer's notion of ‘inter‐thinking’ – to help identify discourse markers that could support teachers in identifying and teaching critical Internet literacy. More work is needed, but it is argued that if our goal is to develop critical Internet literacy, the concept of obuchenie helps us to understand the socio‐cognitive prerequisites of group learning in Internet searching tasks, while the concept of ‘interthinking’ offers us a distribution mechanism that can be applied in helping students acquire the skills of independent and critical analysis as they carry out those tasks.

A unified approach for gathering and exclusive searching on rings under weak assumptions

Consider a set of mobile robots placed on distinct nodes of a discrete, anonymous, and bidirectional ring. Asynchronously, each robot takes a snapshot of the ring, determining the size of the ring and which nodes are either occupied by robots or empty. Based on the observed configuration, it decides whether to move to one of its adjacent nodes or not. In the first case, it performs the computed move, eventually. This model of computation is known as Look-Compute-Move. The computation depends on the required task. In this paper, we solve both the well-known Gathering and Exclusive Searching tasks. In the former problem, all robots must simultaneously occupy the same node, eventually. In the latter problem, the aim is to clear all edges of the graph. An edge is cleared if it is traversed by a robot or if both its endpoints are occupied. We consider the exclusive searching where it must be ensured that two robots never occupy the same node. Moreover, since the robots are oblivious, the clearing is perpetual, i.e., the ring is cleared infinitely often. In the literature, most contributions are restricted to a subset of initial configurations. Here, we design two different algorithms and provide a characterization of the initial configurations that permit the resolution of the problems under very weak assumptions. More precisely, we provide a full characterization (except for few pathological cases) of the initial configurations for which gathering can be solved. The algorithm relies on the necessary assumption of the local-weak multiplicity detection. This means that during the Look phase a robot detects also whether the node it occupies is occupied by other robots, without acquiring the exact number. For the exclusive searching, we characterize all (except for few pathological cases) aperiodic configurations from which the problem is feasible. We also provide some impossibility results for the case of periodic configurations.

Математична теорія оптимального керування в практичних задачах

In this article the literature analysis is provided basing on the history of the maximum principle from its’ very discovery. Also some significant examples of tasks for optimal control in different fields of application are described. Starting from this point the optimal solutions searching tasks concerning printing industry are analyzed. Basing on this the hypothetic task for optimal control in ink and water supply had been stated. While adding the typical transportation delay and the margins set by this phenomenon, the task for optimal control search had been finalized. With this the simplified point with the ink or fountain solution will travel through the complex rollers system in the printing unit that are doing the rotating, oscillating and rotating-oscillate-transporting moves.The conducted research shows the existence of ability to set the process of achieving and constant keeping the ink—water balance, while having some numbers of ink and fountain solution supply according to the number of printing and non-printing elements on the printing form in offset printing.The mathematical model for solving the task of optimal control search while setting and correcting the amounts of ink and fountain solution supply in the preprint preparation and while controlling the print-run itself was proposed. This is crucial for keeping the normalized parameters of optical density and color difference on the imprint, as the trajectory of ink of fountain solution flow change was determined for the corrections in «increase» or «decrease» directions.

Experimental Comparisons of Leading Display and RSVP Display of Chinese Dynamic Text in Searching Tasks

Objective: This study investigates user performance and user perceptions of dynamic Chinese text displays (Leading display and RSVP display) when users search for target information. Background: Today, information searching with dynamic displays is widely used in TV programs, on Internet advertisements, for traffic information systems, and more. Method: A human factors experiment was conducted to compare both displays. Eighteen subjects participated in evaluating two simulated interfaces for the leading display and the RSVP display. Results: The results show that the leading display was better in terms of search time and certain subjective measurements (Easiness, frustration, anxiety). The latter results are consistent with the conclusions of other research efforts showing that dynamic displays are more effective and efficient when reading information. Conclusion: The leading display is more useful for Chinese users in terms of both information searching and information reading. Application: This study helps design dynamic displays written in Chinese texts.

Critical Print Size for Word Search Tasks in Japanese Chinese Characters and Japanese Alphabet

The estimation of optimal print size for reading is often essential in clinical treatment and/or universal design; however, it is not known how to calculate the proper letter size for reading with maximum efficiency. Psychophysics studies have revealed psychometric functions of reading that exhibit a hill-like shape with a plateau of maximum speed and a downfall beyond Critical Print Size (CPS). To control the magnification rate of visual aids for patients with visual impairments, CPS that can indicate the boundary of maximum efficiency is now becoming a noteworthy index to determine optimal letter size. In addition to reading, word searching is also an important task for our living. However, the CPS of word search tasks has not been examined yet. We estimated the CPS of word search from the results of two experiments focused on searching for words in Chinese characters and Japanese alphabet (Katakana: square forms) in Japanese. The functions of the searching tasks showed a hill-like shape almost identical to the reading tasks but with elevated speed, and the CPS were stable around 0 logMAR in both the reading and the searching tasks. Hence, CPS is unsusceptible to tasks and can function as a robust marker for the smallest print size with maximum speed. This finding indicates that CPS is the threshold of proficiency (maximum/reduced) beyond the threshold of vision (visible/invisible). CPS can be a meaningful index to achieve the appropriate control of print size and subsequently help people with visual problems.

A faceted approach to conceptualizing tasks in information seeking

The nature of the task that leads a person to engage in information interaction, as well as of information seeking and searching tasks, have been shown to influence individuals’ information behavior. Classifying tasks in a domain has been viewed as a departure point of studies on the relationship between tasks and human information behavior. However, previous task classification schemes either classify tasks with respect to the requirements of specific studies or merely classify a certain category of task. Such approaches do not lead to a holistic picture of task since a task involves different aspects. Therefore, the present study aims to develop a faceted classification of task, which can incorporate work tasks and information search tasks into the same classification scheme and characterize tasks in such a way as to help people make predictions of information behavior. For this purpose, previous task classification schemes and their underlying facets are reviewed and discussed. Analysis identifies essential facets and categorizes them into Generic facets of task and Common attributes of task. Generic facets of task include Source of task, Task doer, Time, Action, Product, and Goal. Common attributes of task includes Task characteristics and User’s perception of task. Corresponding sub-facets and values are identified as well. In this fashion, a faceted classification of task is established which could be used to describe users’ work tasks and information search tasks. This faceted classification provides a framework to further explore the relationships among work tasks, search tasks, and interactive information retrieval and advance adaptive IR systems design.

Eighth graders’ web searching strategies and outcomes: The role of task types, web experiences and epistemological beliefs

This study reported an investigation of eighth graders’ (14-year-olds) web searching strategies and outcomes, and then analyzed their correlations with students’ web experiences, epistemological beliefs, and the nature of searching tasks. Eighty-seven eighth graders were asked to fill out a questionnaire for probing epistemological beliefs (from positivist to constructivist-oriented views) and finished three different types of searching tasks. Their searching process was recorded by screen capture software and answers were reviewed by two expert teachers based on their accuracy, richness and soundness. Five quantitative indicators were used to assess students’ searching strategies: number of keywords, visited pages, maximum depth of exploration, refinement of keyword, and number of words used in the first keyword. The main findings derived from this study suggested that, students with richer web experiences could find more correct answers in “close-ended” search tasks. In addition, students with better metacognitive skills such as keyword refinement tended to achieve more successful searching outcomes in such tasks. However, in “open-ended” tasks, where questions were less certain and answers were more elaborated, students who had more advanced epistemological beliefs, concurring with a constructivist view, had better searching outcomes in terms of their soundness and richness. This study has concluded that epistemological beliefs play an influential role in open-ended Internet learning environments.

“F” Pattern Scanning of Text and Images in Web Pages

This article discusses users' visual scan paths of web pages containing text and/or images while conducting browsing and searching tasks on an e-commerce website. Participants were exposed to two web pages, one image-based and one text-based, and asked to perform either a search or browse task on each. They were also asked to perform a search task for a non-existent category on the image-based page. Results show that users follow a fairly uniform scan path with greater fixations on images above the fold when browsing through image-based pages. Fixation counts dramatically dropped on images close to the fold and below the fold. The users performing the searching task on the image-based page seemed very efficient. They seemed to employ unique and random scan paths to successfully accomplish the search. Nielsen's ‘F’ pattern (2006) was confirmed in both the text-browse and text-search tasks.

Conceptual framework for tasks in information studies

AbstractToday information‐intensive work tasks in professional settings involve highly dynamic information utilization in which information seeking and searching tasks are taking a more central role. This article considers the concept of task in the context of information studies in order to provide a definitional clarity for task‐based information seeking and retrieval studies. We identify (1) the central task levels as well as (2) the kinds of dimensions connected to the levels from the perspective of information studies. The analysis is aimed to serve as a conceptual starting point for empirical studies in the research area. The focus is on some central aspects of tasks that are recognized within information studies as well as related research areas (e.g., organizational studies). We define two levels of information‐related subtasks: information seeking tasks and information search tasks. Information retrieval tasks are explicitly considered as a specific type of information search task. We describe differences and connections between these task levels. Finally, the implications of the proposed conceptual framework for information studies are discussed.

Interaction Devices and Web Design for Novice Older Users

ABSTRACT This study investigated the effects of interaction devices on the Internet performance of novice older users, and ways to provide appropriate voice assistance to enhance browsing and searching performance of such users. Three experiments were designed and conducted to test three hypotheses. The results indicated that touch screen and handwriting recognition are better than mouse and keyboard in browsing time in the third trial. Touch screen was also found to be better in terms of performance time for keyword search tasks than mouse and voice input in the second trial, and is better in terms of user error for keyword search tasks than mouse and voice input in the first trial. Learning effects were found for using touch screen and handwriting recognition, and mouse and keyboard for browsing and searching tasks. Furthermore, voice-menu assistance was associated with higher satisfaction for browsing tasks.