A Reward Population-Based Differential Genetic Harmony Search Algorithm

To overcome the shortcomings of the harmony search algorithm, such as its slow convergence rate and poor global search ability, a reward population-based differential genetic harmony search algorithm is proposed. In this algorithm, a population is divided into four ordinary sub-populations and one reward sub-population, for each of which the evolution strategy of the differential genetic harmony search is used. After the evolution, the population with the optimal average fitness is combined with the reward population to produce a new reward population. During an experiment, tests were conducted first on determining the value of the harmony memory size (HMS) and the harmony memory consideration rate (HMCR), followed by an analysis of the effect of their values on the performance of the proposed algorithm. Then, six benchmark functions were selected for the experiment, and a comparison was made on the calculation results of the standard harmony memory search algorithm, reward population harmony search algorithm, differential genetic harmony algorithm, and reward population-based differential genetic harmony search algorithm. The result suggests that the reward population-based differential genetic harmony search algorithm has the merits of a strong global search ability, high solving accuracy, and satisfactory stability.

How Does Approaching a Lead Vehicle and Monitoring Request Affect Drivers’ Takeover Performance? A Simulated Driving Study with Functional MRI

With the popularization and application of conditionally automated driving systems, takeover requirements are becoming more and more frequent, and the subsequent takeover safety problems have attracted attention. The present study used functional magnetic resonance imaging (fMRI) technology, combined with driving simulation experiments, to study in depth the effects of critical degree and monitor request (MR) 30 s in advance on drivers’ visual behavior, takeover performance and brain activation. Results showed that MR can effectively improve the driver’s visual and takeover performance, including visual reaction times, fixation frequency and duration, takeover time, and takeover mode. The length of the reserved safety distance can significantly affect the distribution of longitudinal acceleration. Critical or non-critical takeover has a significant impact on the change of pupil diameter and the standard deviation of lateral displacement. Five brain regions, including the middle occipital gyrus (MOG), fusiform gyrus (FG), middle temporal gyrus (MTG), precuneus and precentral, are activated under the stimulation of a critical takeover scenario, and are related to cognitive behaviors such as visual cognition, distance perception, memory search and movement association.

Application of an artificial intelligence algorithm model of memory retrieval and roaming in sorting Chinese medicinal materials

In order to capture autobiographical memory, inspired by the development of human intelligence, a computational AM model for autobiographical memory is proposed in this paper, which is a three-layer network structure, in which the bottom layer encodes the event-specific knowledge comprising 5W1H, and provides retrieval clues to the middle layer, encodes the related events, and the top layer encodes the event set. According to the bottom-up memory search process, the corresponding events and event sets can be identified in the middle layer and the top layer respectively; At the same time, AM model can simulate human memory roaming through the process of rule-based memory retrieval. The computational AM model proposed in this paper not only has robust and flexible memory retrieval, but also has better response performance to noisy memory retrieval cues than the commonly used memory retrieval model based on keyword query method, and can also imitate the roaming phenomenon in memory.

Event boundaries are steppingstones for memory retrieval

Personal experience extends over time. When we recall memories from our lives, we often scan extended episodes to remember, for instance, where we placed our car keys. Here we investigate the hypothesis that high level structure, marked by boundaries between events, guides us through this retrieval process. We present a model of memory search in which humans can replay past experience on a fine-grained temporal scale, but also skip ahead to the beginning of a new event in order to speed up the retrieval process. In a naturalistic interview paradigm, we provide evidence in human response times for such a skipping mechanism: When participants scanned extended segments from a movie in their memory, their reaction times were better explained by a model incorporating the number of event boundaries in the segment and the distance of the target to the previous event boundary (with both predictors explaining significant variance), compared to a model incorporating the actual duration of a segment. This supports the idea that, in scanning their memory, humans can skip to the beginning of a new event if they decide that the target is not present in that event; this has the effect of decoupling their memory scanning reaction times from the actual duration of the segment. This conclusion is further supported by the results of a second study where participants were asked to do detailed mental simulation instead of memory scanning. Participants took substantially longer to perform such mental simulation compared to participants that scanned their memory. Those mental simulation times were still explained better by a model where participants skip, but -- compared to memory scanning -- the threshold for skipping was much higher.

Associations of word memory, verbal fluency, processing speed and crystallised cognitive ability with one-legged balance performance in mid and later life

Background Cognitive integration of sensory input and motor output plays an important role in balance. Despite this, it is not clear if specific cognitive processes are associated with balance and how these associations change with age. We examined longitudinal associations of word memory, verbal fluency, search speed and reading ability with repeated measures of one-legged balance performance. Methods Up to 2934 participants in the MRC National Survey of Health and Development, a British birth cohort study, were included. At age 53, word memory, verbal fluency, search speed and reading ability were assessed. One-legged balance times (eyes closed) were measured at ages 53, 60-64 and 69 years. Associations between each cognitive measure and balance time were assessed using random-effects models. Adjustments were made for sex, death, attrition, height, body mass index, health conditions, health behaviours, education, and occupational class. Results In sex-adjusted models, one SD higher scores in word memory, search speed and verbal fluency were associated with 14.1% (95%CI: 11.3,16.8), 7.2% (4.4,9.9) and 10.3% (7.5,13.0) better balance times at age 53, respectively. Higher reading scores were associated with better balance, although this association plateaued. Associations were partially attenuated in mutually-adjusted models and effect sizes were smaller at ages 60-64 and 69. In fully-adjusted models, associations were largely explained by education, although remained for word memory and search speed. Conclusions Higher cognitive performance across all measures was independently associated with better balance performance in midlife. Identification of individual cognitive mechanisms involved in balance could lead to opportunities for targeted interventions in midlife.

The role of metamemory in autobiographical memory performance in dysphoric individuals

Autobiographical memory (AM) performance in individuals with depressive symptoms has repeatedly been shown to be overgeneral (OGM) in nature, and characterized by summaries of repeated events or long periods of time rather than a single event tied to a unique spatial and temporal context. The present body of work was designed to address the metamnemonic aspects of AM performance in dysphoric individuals, with the underlying motivation being that OGM may not be a unique phenomenon specific to depression or AM, and that it may reflect a more general pattern of memory impairment. The studies presented herein examine various aspects of metamemory and other memory processes that may offer a parsimonious account of OGM as poor event memory in general, rather than a specific standalone finding. In Study 1 several metamnemonic processes were investigated using a quantity-accuracy profile approach. Here, the results showed that performance between dysphoric and non-dysphoric participants was nearly indistinguishable on measures of calibration, resolution, grain-size setting, and criterion setting, suggesting that these aspects of metamemory are intact in dysphoria for immediately tested material. Study 2 examined whether it is possible to “create” OGMs by employing a delay manipulation for both autobiographical (3 day delay) and laboratory-based events (7 day delay). Indeed, the results from this study showed that the performance on both tasks declines for both groups, but that this effect was of a greater magnitude in the dysphoric group. Critically, no differences emerged for immediately tested information. Finally, Study 3 examined the role of working memory and memory search strategies in the recollection of autobiographically relevant information. The results from Study 3 showed that dysphoric individuals may engage in a less organized search strategy than non-dysphoric participants as exhibited by a tendency to switch set in the midst of thematically related information. Taken as a whole, these data indicate that OGM may be attributable to deficits in memory search strategies in conjunction with memories that may be more prone to decay and/or forgetting, suggesting that OGM may not be a depression-specific phenomenon, but rather the downstream deficit of degraded memory representation.

The role of metamemory in autobiographical memory performance in dysphoric individuals

Autobiographical memory (AM) performance in individuals with depressive symptoms has repeatedly been shown to be overgeneral (OGM) in nature, and characterized by summaries of repeated events or long periods of time rather than a single event tied to a unique spatial and temporal context. The present body of work was designed to address the metamnemonic aspects of AM performance in dysphoric individuals, with the underlying motivation being that OGM may not be a unique phenomenon specific to depression or AM, and that it may reflect a more general pattern of memory impairment. The studies presented herein examine various aspects of metamemory and other memory processes that may offer a parsimonious account of OGM as poor event memory in general, rather than a specific standalone finding. In Study 1 several metamnemonic processes were investigated using a quantity-accuracy profile approach. Here, the results showed that performance between dysphoric and non-dysphoric participants was nearly indistinguishable on measures of calibration, resolution, grain-size setting, and criterion setting, suggesting that these aspects of metamemory are intact in dysphoria for immediately tested material. Study 2 examined whether it is possible to “create” OGMs by employing a delay manipulation for both autobiographical (3 day delay) and laboratory-based events (7 day delay). Indeed, the results from this study showed that the performance on both tasks declines for both groups, but that this effect was of a greater magnitude in the dysphoric group. Critically, no differences emerged for immediately tested information. Finally, Study 3 examined the role of working memory and memory search strategies in the recollection of autobiographically relevant information. The results from Study 3 showed that dysphoric individuals may engage in a less organized search strategy than non-dysphoric participants as exhibited by a tendency to switch set in the midst of thematically related information. Taken as a whole, these data indicate that OGM may be attributable to deficits in memory search strategies in conjunction with memories that may be more prone to decay and/or forgetting, suggesting that OGM may not be a depression-specific phenomenon, but rather the downstream deficit of degraded memory representation.