41,121 results on '"hidden Markov model"'
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2. Detection Windows from Hidden Markov Model for Discovering Varying Causal Relations Between Time Series
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Wang, Kaijun, Fang, Ying, Luo, Tianjian, Ghosh, Ashish, Editorial Board Member, Zhou, Lizhu, Editorial Board Member, Zhou, Xiao-Hua, editor, and Jia, Jinzhu, editor
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- 2025
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3. HMM-CPM: a cloud instance resource prediction method tracing the workload trends via hidden Markov model.
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Yang, Zhihe, Wang, Xiaogang, Li, Rongting, and Liu, Yangli
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HIDDEN Markov models , *MARKOV processes , *PREDICTION models , *CLOUD computing , *PROBLEM solving - Abstract
Accurate prediction of cloud resource instances is becoming increasingly important for public cloud users and cloud service providers, because it touches on the reasonable reservation of cloud resources with minimize costs. However, current methods do not predict the instance types of cloud resources based on the application workloads from users, and less consider the characteristics of workload data changes in the real-time prediction. To solve these problems, this paper proposes an application workload-dependent cloud resource instance prediction model to predict appropriate cloud instance resource usage in a timely manner. Firstly, we adopt a trend degree (TD) to classify all requested workloads into three types of wave trend patterns. Next, a Hidden Markov model based cloud resource prediction method (HMM-CPM) tracing the requested workload trends is presented. Finally, the reasonable cloud instance types following the patterns of the requested workloads can be predicted. The simulation results show that the proposed method can predict cloud resource instance types in the scenario with certain workload fluctuation, and the prediction accuracy is higher than the existing related approaches. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Asynchronous fault detection filtering for nonhomogeneous Markov jump systems with dynamic quantization subject to a novel hybrid cyber attacks.
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Hua, Mingang, Sun, Ni, Deng, Feiqi, Fei, Juntao, and Chen, Hua
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The problem of asynchronous fault detection filtering for nonhomogeneous Markov jumping systems with dynamic quantization and hybrid cyber attacks is addressed in this paper. The introduction of polytopic-structure-based transition probabilities is employed to describe the nonhomogeneous Markov process. An asynchronous fault detection filter is proposed, which utilizes the hidden Markov model to achieve comprehensive access to the plant mode information. Prior to transmission to the filter, the measurement output of the system undergoes quantization using a dynamic quantizer. The novel hybrid cyber attacks model being discussed involves four types of attacks: deception attacks, denial-of-service attacks, no attack, and hybrid attacks with both deception and denial-of-service attacks. By constructing Lyapunov functional, sufficient conditions are presented for achieving the stochastic stability with H ∞ performance. Under the complex network environment, the industrial application of the presented asynchronous fault detection filtering model is demonstrated on a non-isothermal continuous stirred tank reactor. The simulation results confirm the practicality of the proposed design method. • The dynamic quantizer is adopted to quantify measurement output signals to reduce information exchange frequency and communication burden. • A convex polyhedron is used to describe the time-varying transition probability matrix. • Due to the mode information between the filter and the plant cannot be fully obtained in the networked control system, a HMM-based asynchronous mechanism is proposed. • In order to improve the system performance, a novel hybrid network attack model is proposed, which includes four attack modes. [ABSTRACT FROM AUTHOR]
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- 2024
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5. On regime changes in text data using hidden Markov model of contaminated vMF distribution.
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Zhang, Yingying, Sarkar, Shuchismita, Chen, Yuanyuan, and Zhu, Xuwen
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This paper presents a novel methodology for analyzing temporal directional data with scatter and heavy tails. A hidden Markov model with contaminated von Mises-Fisher emission distribution is developed. The model is implemented using forward and backward selection approach that provides additional flexibility for contaminated as well as non-contaminated data. The utility of the method for finding homogeneous time blocks (regimes) is demonstrated on several experimental settings and two real-life text data sets containing presidential addresses and corporate financial statements respectively. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Prior exposure to racial discrimination and patterns of acute parasympathetic nervous system responses to a race‐related stress task among Black adults.
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Volpe, Vanessa V., Kendall, Emmett B., Collins, Abbey N., Graham, Matthew G., Williams, Jonathan P., and Holochwost, Steven J.
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PARASYMPATHETIC nervous system , *BLACK people , *HIDDEN Markov models , *RACE discrimination , *SINUS arrhythmia , *LIFE course approach - Abstract
Black adults' prior exposure to racial discrimination may be associated with their acute parasympathetic reactivity to and recovery from a new race‐related stressor. Existing analytical approaches to investigating this link obscure nuances in the timing, magnitude, and patterns of these acute parasympathetic nervous system (PNS) responses. In a re‐analysis of a prior study, we utilize an hidden Markov model (HMM) approach to examine how prior experiences of racial discrimination are associated with intraindividual patterns of (1) physiological states of PNS activity and (2) patterns of and variability in transitions between these physiological states. Participants (N = 118) were Black young adults (range 18–29 years; Mage = 19.67, SDage = 2.04) who completed an online survey to index prior racial discrimination exposure, followed by an in‐person lab visit during which their PNS activity in response to a race‐related stress task was measured via electrocardiogram and converted into respiratory sinus arrhythmia. HMMs indicated evidence for two states: baseline and a second state representing a significant reduction in respiratory sinus arrhythmia. Most participants (93.22%) demonstrated a blunted response to the task, indicating that they did not transition from baseline during the procedure. Prior racial discrimination was not associated with HMM states or state transition parameters. Blunted physiological responses may be an important area of future investigation that could inform early life course mental and physical health screenings. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Movement decisions driving metapopulation connectivity respond to social resources in a long-lived ungulate, bighorn sheep (Ovis canadensis).
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Ricci, Lauren E., Cox, Mike, and Manlove, Kezia R.
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BIGHORN sheep , *HIDDEN Markov models , *DISCRETE choice models , *ANIMAL mechanics , *MARKOV processes - Abstract
The spatial availability of social resources is speculated to structure animal movement decisions, but the effects of social resources on animal movements are difficult to identify because social resources are rarely measured. Here, we assessed whether varying availability of a key social resource—access to receptive mates—produces predictable changes in movement decisions among bighorn sheep in Nevada, the United States. We compared the probability that males made long-distance 'foray' movements, a critical driver of connectivity, across three ecoregions with varying temporal duration of a socially mediated factor, breeding season. We used a hidden Markov model to identify foray events and then quantified the effects of social covariates on the probability of foray using a discrete choice model. We found that males engaged in forays at higher rates when the breeding season was short, suggesting that males were most responsive to the social resource when its existence was short lived. During the breeding season, males altered their response to social covariates, relative to the non-breeding season, though patterns varied, and age was associated with increased foray probability. Our results suggest that animals respond to the temporal availability of social resources when making the long-distance movements that drive connectivity. This article is part of the theme issue 'The spatial–social interface: a theoretical and empirical integration'. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Predator–prey space use and landscape features influence movement behaviors in a large‐mammal community.
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Bassing, Sarah B., Satterfield, Lauren, Ganz, Taylor R., DeVivo, Melia, Kertson, Brian N., Roussin, Trent, Wirsing, Aaron J., and Gardner, Beth
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Predator hunting strategies, such as stalking versus coursing behaviors, are hypothesized to influence antipredator behaviors of prey and can describe the movement behaviors of predators themselves. Predators and prey may alter their movement in relation to predator hunting modes, yet few studies have evaluated how these strategies influence movement behaviors of free‐ranging animals in a multiple‐predator, multiple‐prey system. We fit hidden Markov models (HMM) with movement data derived from >400 GPS‐collared ungulates and large predators in eastern Washington, USA. We used these models to test our hypotheses that stalking (cougars [Puma concolor]) and coursing (gray wolves [Canis lupus]) predators would exhibit different broad‐scale movement behaviors consistent with their respective hunting strategies in areas that increased the likelihood of encountering or capturing ungulate prey (e.g., habitats selected by deer [Odocoileus spp.]). Similarly, we expected that broadscale movement behaviors of prey would change in response to background levels of predation risk associated with each predator's hunting strategy. We found that predators and ungulate prey adjusted their broadscale movements in response to one another's long‐term patterns of habitat selection but not based on differences in predator‐hunting strategies. Predators changed their movement behaviors based on the type of prey, whereas ungulates generally reduced movement in areas associated with large predators, regardless of the predator's hunting strategy. Both predator and prey movements varied in response to landscape features but not necessarily based on habitat that would facilitate specific hunting behaviors. Our results suggest that predators and prey adjust their movements at broad temporal scales in relation to long‐term patterns of risk and resource distributions, potentially influencing their encounter rates with one another at finer spatiotemporal scales. Habitat features further influenced changes in movement, resulting in a complex combination of movement behaviors in multiple‐predator, multiple‐prey systems. [ABSTRACT FROM AUTHOR]
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- 2024
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9. A Novel Automatic Map Matching Method Based on Hybrid Computing Framework of Hidden Markov Model and Conditional Random Field.
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Hu, Dongfeng and Zong, Liansong
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HIDDEN Markov models , *MARKOV processes , *AUTOMATIC classification , *TECHNOLOGICAL progress , *CLASSIFICATION - Abstract
In recent years, automatic map matching has received great technical progress. However, when it comes to vague matching situations such as improper vocabulary use, there still lack reliable solutions. To handle the current gap, this paper proposes a novel automatic map matching method based on the hybrid computing framework of hidden Markov model (HMM) and conditional random field. First, the data filtering is completed by performing second-order transformation towards automatic matching conditions of HMM. Then, the data classification is completed using automatic data classification based on the conditional random field. After that, a hybrid computing framework with spatial elements and layer selection is built to generate map matching results. Finally, some simulation experiments are conducted for evaluation. For one thing, the trend of matching accuracy changes under specified conditions is basically the same as that of nonspecified conditions. The maximum difference in matching calculation values is about 3 times. However, once the vocabulary continues to increase, the difference in matching results between the two narrows to 10–20%. For the other thing, the matching accuracy of a specified state is higher than that of sending a specified state. While nonspecified fuzzy matching accuracy is about 3 times higher and nonspecified precision matching accuracy is about 50% higher. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Dynamic transient brain states in preschoolers mirror parental report of behavior and emotion regulation.
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Toffoli, Lisa, Zdorovtsova, Natalia, Epihova, Gabriela, Duma, Gian Marco, Del Popolo Cristaldi, Fiorella, Pastore, Massimiliano, Astle, Duncan E., and Mento, Giovanni
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CONTROL (Psychology) , *COGNITIVE ability , *COGNITIVE development , *MARKOV processes , *EMOTION regulation - Abstract
The temporal dynamics of resting‐state networks may represent an intrinsic functional repertoire supporting cognitive control performance across the lifespan. However, little is known about brain dynamics during the preschool period, which is a sensitive time window for cognitive control development. The fast timescale of synchronization and switching characterizing cortical network functional organization gives rise to quasi‐stable patterns (i.e., brain states) that recur over time. These can be inferred at the whole‐brain level using hidden Markov models (HMMs), an unsupervised machine learning technique that allows the identification of rapid oscillatory patterns at the macroscale of cortical networks. The present study used an HMM technique to investigate dynamic neural reconfigurations and their associations with behavioral (i.e., parental questionnaires) and cognitive (i.e., neuropsychological tests) measures in typically developing preschoolers (4–6 years old). We used high‐density EEG to better capture the fast reconfiguration patterns of the HMM‐derived metrics (i.e., switching rates, entropy rates, transition probabilities and fractional occupancies). Our results revealed that the HMM‐derived metrics were reliable indices of individual neural variability and differed between boys and girls. However, only brain state transition patterns toward prefrontal and default‐mode brain states, predicted differences on parental‐report questionnaire scores. Overall, these findings support the importance of resting‐state brain dynamics as functional scaffolds for behavior and cognition. Brain state transitions may be crucial markers of individual differences in cognitive control development in preschoolers. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Developing a secure voice recognition service on Raspberry Pi.
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Van-Hoan Le, Nhu-Quynh Luc, and Duc-Huy Quach
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ARTIFICIAL neural networks ,ADVANCED Encryption Standard ,HIDDEN Markov models ,FAST Fourier transforms ,RSA algorithm - Abstract
In this study, we present a novel voice recognition service developed on the Raspberry Pi 4 model B platform, leveraging the fast Fourier transform (FFT) for efficient speech-to-digital signal conversion. By integrating the hidden Markov model (HMM) and artificial neural network (ANN), our system accurately reconstructs speech input. We further fortify this service with dual-layer encryption using the Rivest-Shamir-Adleman (RSA) and advanced encryption standard (AES) methods, achieving encryption and decryption times well suited for real-time applications. Our results demonstrate the system's robustness and efficiency: speech processing within 1.2 to 1.9 seconds, RSA 2048-bit encryption in 2 to 6 milliseconds, RSA decryption in 6 to 10 milliseconds, and AES-GCM 256-bit encryption and decryption in approximately 2.6 to 3 seconds. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Jobs-housing balance and travel patterns among different occupations as revealed by Hidden Markov mixture models: the case of Hong Kong.
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Zhang, Feiyang, Loo, Becky P. Y., Lan, Hui, Chan, Antoni B., and Hsiao, Janet H.
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HIDDEN Markov models ,EXPECTATION-maximization algorithms ,TRAFFIC congestion ,MARKOV processes ,CITIES & towns - Abstract
The spatial mismatch between jobs and housing in cities creates long daily travels that exacerbate climate change, air pollution, and traffic congestion. Yet, not enough research on occupational differences has been done. This study first applies the Hidden Markov Mixture Model (H3M) to model travel patterns for different occupation groups in Hong Kong. Then, the Variational Bayesian Hierarchical EM algorithm is used to identify common lifestyle clusters. Next, a binary logistic regression is developed to examine whether the lifestyle clusters can be explained by jobs-housing balance. This study is among the first to consider travel patterns as a Markov process and apply H3M to examine jobs-housing balance by fine-grain occupation group. The method is transferable and universally applicable; and the results provide occupation-specific insights on jobs-housing balance in an Asian context. The research findings suggest that different occupation groups have different travel patterns in Hong Kong. Two lifestyle clusters, "balanced and compact activity space" and "work-oriented and extensive travels", are unveiled. Notably, the latter is associated a lower level of jobs-housing balance. Some occupations in the quaternary industry ("information and communications", "profession, science and technology", "real estate", and "finance and insurance") are having more serious jobs-housing imbalance. The paper concludes with a discussion on improving the occupation-specific jobs-housing balance in accordance with Hong Kong's future development goals. [ABSTRACT FROM AUTHOR]
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- 2024
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13. Naivety dies with the calf: calf loss to human hunters imposes behavioral change in a long-lived but heavily harvested ungulate.
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Graf, Lukas, Thurfjell, Henrik, Ericsson, Göran, and Neumann, Wiebke
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HIDDEN Markov models ,ANTIPREDATOR behavior ,HABITAT selection ,MOOSE ,HUMAN settlements - Abstract
Background: In prey, patterns of individual habitat selection and movement can be a consequence of an individuals' anti-predator behavior. Adjustments of anti-predator behavior are important for prey to increase their survival. Hunters may alter the anti-predator behavior of prey. In long-lived animals, experience may cause behavioral changes during individuals' lifetime, which may result in altered habitat selection and movement. Our knowledge of which specific events related to hunting activity induce behavioral changes in solitary living species is still limited. Methods: We used offspring loss in a solitary and long-lived ungulate species, moose (Alces alces), as our model system. We investigated whether offspring loss to hunters induces behavioral changes in a species subjected to heavy human harvest but free from natural predation. To test for behavioral change in relation to two proxies for experience (calf fate and age), we combined movement data from 51 adult female moose with data on their offspring survival and female age. We tested for adjustments in females' habitat selection and movement following calf harvest using Hidden Markov Models and integrated Step Selection Analysis to obtain behavioral state specific habitat selection coefficients. Results: We found that females with a harvested calf modified habitat selection and movement during the following hunting season. Female moose selected for shorter distance to roads during the night, selected for shorter distance to forests and greater distance to human settlements following calf harvest than females who had not lost a calf. The survival of twins in a given hunting season was related to female age. Older females we more likely to have twins survive the hunting season. Conclusions: Our findings suggest that losing offspring to human harvest imposes behavioral changes in a long-lived ungulate species, leading to adjustments in females' habitat selection and movement behavior, which may lower the risk of encountering hunters. In our study, female moose that experienced calf loss selected for lower distance to forest and selected for greater distance to human settlements during periods of high hunting pressure compared to females without the experience of calf loss during the previous hunting season. We interpret this as potential learning effects. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Faster computation of likelihood gradients for discrete observation Hidden Markov model.
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Chawla, Manesh
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DATA compression , *MARKOV processes , *PARAMETER estimation , *ALGORITHMS - Abstract
AbstractIn this article we present an algorithm for faster computation of HMM likelihood gradients when the observation space is discrete. Many parameter estimation algorithms for HMM require repeated computation of gradient to optimize the likelihood function. Gradient computation is costly therefore its faster computation can improve their performance greatly. We develop an algorithm for faster computation of gradient using ideas from data compression. Our algorithm decreased computation cost of gradients by a factor of three to five. We apply our methods to speed up the Baum-Welch algorithm by similar factors. [ABSTRACT FROM AUTHOR]
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- 2024
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15. Adaptive neural network‐based security asynchronous control for uncertain Markov jump power systems with dead zone under DoS attack.
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Dong, Shanling, Liu, Enjun, Wang, Bo, Liu, Meiqin, and Chen, Guanrong
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HIDDEN Markov models , *MARKOVIAN jump linear systems , *DENIAL of service attacks , *STATE feedback (Feedback control systems) , *MARKOV processes - Abstract
The article deals with the security control stabilization problem of uncertain Markov jump power systems with input dead zone under stochastic denial‐of‐service (DoS) attack. DoS attack is modeled as a discrete‐time Markov process. Dual hidden Markov models are respectively used to detect the modes of the original power systems and the one under DoS attack. Based on the detected modes and neural networks (NNs), adaptive NN‐based security asynchronous control strategies are proposed, where both state feedback and output feedback are studied simultaneously. With the developed control laws, all trajectories of the closed‐loop systems are bounded stable in the stochastic setting. Simulation results demonstrate the correctness and usefulness of the proposed techniques. [ABSTRACT FROM AUTHOR]
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- 2024
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16. Optimizing 4G Cellular Networks: A Predictive Analysis Using Hidden Markov Models.
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Kosasih, Eka and Oktavia, Tanty
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MACHINE learning , *DATA mining , *STANDARD deviations , *4G networks , *5G networks - Abstract
Automating performance improvement in 4G cellular networks is a challenging research area due to existing limitations in artificial intelligence and machine learning applications. This study addresses these challenges by developing a data analysis model using Hidden Markov Models (HMM) to predict Key Performance Indicators (KPIs) and automate performance assessments. Data was analyzed from 1600 new sites of a mobile operator in Indonesia, collected from July 2023 to January 2024. The methodology follows Knowledge Discovery in Database (KDD) for data mining and applying HMMs to forecast KPIs such as eRAB Drop Rate and Setup Success Rate. The model achieved a Mean Absolute Error (MAE) of 0.005 and a Root Mean Square Error (RMSE) of 0.069 for eRAB Drop Rate, with an F1 Score reaching up to 99.76%. The performance of the model improves with an increasing number of observation states, particularly for Inter Frequency Handover Success Rate (HOSR) and RRC Connection Setup Success Rate. Despite strong performance, there is potential for further enhancement, especially for KPIs with high variability like Intra Frequency HOSR. This research demonstrates that HMMs are effective in predicting KPIs with high accuracy, rather than traditional time-series models. The results align with recent studies and suggest that combining HMMs with techniques such as LSTM or Random Forests could improve predictive accuracy. These methods are also applicable to another technology, especially 5G networks, offering valuable insights for more effective network management and performance optimization. [ABSTRACT FROM AUTHOR]
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- 2024
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17. Facial Recognition Using Hidden Markov Model and Convolutional Neural Network.
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Bilal, Muhammad, Razzaq, Saqlain, Bhowmike, Nirman, Farooq, Azib, Zahid, Muhammad, and Shoaib, Sultan
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CONVOLUTIONAL neural networks , *HIDDEN Markov models , *SINGULAR value decomposition , *DATABASES , *PRINCIPAL components analysis - Abstract
Face recognition (FR) uses a passive approach to person authentication that avoids face-to-face contact. Among different FR techniques, most FR approaches place little emphasis on reducing powerful cryptography and instead concentrate on increasing recognition rates. In this paper, we have proposed the Hidden Markov Model (HMM) and convolutional Neural Network (CNN) models for FR by using ORL and Yale datasets. Facial images from the given data sets are divided into 3 portions, 4 portions, 5 portions, and 6 portions corresponding to their respective HMM hidden states being used in the HMM model. Quantized levels of eigenvalues and eigenvector coefficients of overlapping blocks of facial images define the observation states of the HMM model. For image selection and rejection, a threshold is calculated using singular value decomposition (SVD). After training HMM on 3 states HMM, 4 states HMM, 5 states HMM, and 6 states HMM, the recognition accuracies are 96.5%, 98.5%, 98.5%, and 99.5%, respectively, on the ORL database and 90.6667%, 94.6667%, 94.6667%, and 94.6667% on the Yale database. The CNN model uses convolutional layers, a max-pooling layer, a flattening layer, a dense layer, and a dropout layer. Relu is used as the activation function in all layers except in the last layer, where softmax is used as the activation function. Cross entropy is used as a loss function, and we have used the Adam optimizer in our proposed algorithm. The proposed CNN model has given 100% training and testing accuracy on the ORL data set. While using the Yale data set, the CNN model has a training accuracy of 100% and a testing accuracy of 85.71%. In this paper, our proposed model showed that the HMM model is cost-effective with lesser accuracy, while the CNN model is more accurate as compared to HMM but has a higher computational cost. [ABSTRACT FROM AUTHOR]
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- 2024
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18. Evidence of longitudinal differences in spring migration strategies of an Arctic‐nesting goose.
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VonBank, Jay A., Kraai, Kevin J., Collins, Daniel P., Link, Paul T., Weegman, Mitch D., Cao, Lei, and Ballard, Bart M.
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BIRD migration , *WHITE-fronted goose , *MATING grounds , *MIGRATORY birds , *GPS receivers - Abstract
During spring, migratory birds are required to optimally balance energetic costs of migration across heterogeneous landscapes and weather conditions to survive and reproduce successfully. Therefore, an individual's migratory performance may influence reproductive outcomes. Given large‐scale changes in land use, climate, and potential carry‐over effects, understanding how individuals migrate in relation to breeding outcomes is critical to predicting how future scenarios may affect populations. We used GPS tracking devices on 56 Greater White‐fronted Geese (Anser albifrons) during four spring migrations to examine whether migration characteristics influenced breeding propensity and breeding outcome. We found a strong longitudinal difference in arrival to the breeding areas (18 days earlier), pre‐nesting duration (90.9% longer), and incubation initiation dates (9 days earlier) between western‐ and eastern‐Arctic breeding regions, with contrasting effects on breeding outcomes, but no migration characteristic strongly influenced breeding outcome. We found that breeding region influenced whether an individual likely pursued a capital or income breeding strategy. Where individuals fell along the capital‐income breeding continuum was influenced by longitude, revealing geographic effects of life‐history strategy among conspecifics. Factors that govern breeding outcomes likely occur primarily upon arrival to breeding areas or are related to individual quality and previous breeding outcome, and may not be directly tied to migratory decision‐making across broad scales. [ABSTRACT FROM AUTHOR]
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- 2024
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19. Exact Decoding of a Sequentially Markov Coalescent Model in Genetics.
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Ki, Caleb and Terhorst, Jonathan
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HIDDEN Markov models , *POPULATION genetics , *FREQUENTIST statistics , *GENETIC variation , *MARKOV processes - Abstract
In statistical genetics, the sequentially Markov coalescent (SMC) is an important family of models for approximating the distribution of genetic variation data under complex evolutionary models. Methods based on SMC are widely used in genetics and evolutionary biology, with significant applications to genotype phasing and imputation, recombination rate estimation, and inferring population history. SMC allows for likelihood-based inference using hidden Markov models (HMMs), where the latent variable represents a genealogy. Because genealogies are continuous, while HMMs are discrete, SMC requires discretizing the space of trees in a way that is awkward and creates bias. In this work, we propose a method that circumvents this requirement, enabling SMC-based inference to be performed in the natural setting of a continuous state space. We derive fast, exact procedures for frequentist and Bayesian inference using SMC. Compared to existing methods, ours requires minimal user intervention or parameter tuning, no numerical optimization or E-M, and is faster and more accurate. for this article are available online. [ABSTRACT FROM AUTHOR]
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- 2024
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20. Comparison between EEG and MEG of static and dynamic resting‐state networks.
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Cho, SungJun, van Es, Mats, Woolrich, Mark, and Gohil, Chetan
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FUNCTIONAL magnetic resonance imaging , *HIDDEN Markov models , *LARGE-scale brain networks , *MAGNETIC resonance imaging , *MAGNETOENCEPHALOGRAPHY - Abstract
The characterisation of resting‐state networks (RSNs) using neuroimaging techniques has significantly contributed to our understanding of the organisation of brain activity. Prior work has demonstrated the electrophysiological basis of RSNs and their dynamic nature, revealing transient activations of brain networks with millisecond timescales. While previous research has confirmed the comparability of RSNs identified by electroencephalography (EEG) to those identified by magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI), most studies have utilised static analysis techniques, ignoring the dynamic nature of brain activity. Often, these studies use high‐density EEG systems, which limit their applicability in clinical settings. Addressing these gaps, our research studies RSNs using medium‐density EEG systems (61 sensors), comparing both static and dynamic brain network features to those obtained from a high‐density MEG system (306 sensors). We assess the qualitative and quantitative comparability of EEG‐derived RSNs to those from MEG, including their ability to capture age‐related effects, and explore the reproducibility of dynamic RSNs within and across the modalities. Our findings suggest that both MEG and EEG offer comparable static and dynamic network descriptions, albeit with MEG offering some increased sensitivity and reproducibility. Such RSNs and their comparability across the two modalities remained consistent qualitatively but not quantitatively when the data were reconstructed without subject‐specific structural MRI images. [ABSTRACT FROM AUTHOR]
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- 2024
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21. Composite‐observer‐based asynchronous control for hidden Markov nonlinear systems with disturbances.
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Cheng, Weidi, He, Shuping, Wang, Hai, and Sun, Changyin
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MARKOVIAN jump linear systems , *HIDDEN Markov models , *BACKSTEPPING control method , *NONLINEAR systems , *MARKOV processes - Abstract
Summary: In this article, an asynchronous adaptive tracking control approach is presented for a type of hidden Markov jump nonlinear systems with external disturbances. In this joint jump process model, hidden Markov model signifies the dynamics of the actual system, whereas the signal emits from the detector symbolizes the transmitted information. This leads to the phenomenon of asynchronization between the modes of the system and that of the controller. Accordingly, an asynchronous observer is developed by using the mode information from the detector to develop an asynchronous control approach. The observer contains a disturbance estimation part, to compensate the unknown external inputs. Utilizing the backstepping scheme, a strict‐feedback asynchronous tracking controller is formulated, guaranteeing that all signals within the closed‐loop system are semi‐globally uniformly ultimately bounded in probability. Finally, the validity of the presented methodology is illustrated by means of a simulation example. [ABSTRACT FROM AUTHOR]
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- 2024
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22. Efficiently bounding deadline miss probabilities of Markov chain real-time tasks.
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Friebe, Anna, Marković, Filip, Papadopoulos, Alessandro V., and Nolte, Thomas
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In real-time systems analysis, probabilistic models, particularly Markov chains, have proven effective for tasks with dependent executions. This paper improves upon an approach utilizing Gaussian emission distributions within a Markov task execution model that analyzes bounds on deadline miss probabilities for tasks in a reservation-based server. Our method distinctly addresses the issue of runtime complexity, prevalent in existing methods, by employing a state merging technique. This not only maintains computational efficiency but also retains the accuracy of the deadline-miss probability estimations to a significant degree. The efficacy of this approach is demonstrated through the timing behavior analysis of a Kalman filter controlling a Furuta pendulum, comparing the derived deadline miss probability bounds against various benchmarks, including real-time Linux server metrics. Our results confirm that the proposed method effectively upper-bounds the actual deadline miss probabilities, showcasing a significant improvement in computational efficiency without significantly sacrificing accuracy. [ABSTRACT FROM AUTHOR]
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- 2024
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23. Energy demand pattern analysis in South Korea using hidden Markov model‐based classification.
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Lee, Jaeyong and Hwang, Beom Seuk
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HIDDEN Markov models ,ENERGY consumption ,RESIDENTIAL patterns ,MARKOV processes ,TIME series analysis - Abstract
Understanding energy demand patterns in the residential sector is crucial for improving energy efficiency through demand‐side management. Load curve classification is a useful method for analyzing energy demand patterns. In this paper, we employ a hidden Markov model (HMM)‐based classification to residential load curves in South Korea. We also investigate how the number of hidden states affects classification performance by allowing HMM to train with a different number of hidden states for each class. We compare our HMM‐based method with several state‐of‐the‐art models and find that it outperforms other competing models in multiple datasets. Additionally, we use the fitted HMM model to make inferences about the load curves, gaining deeper insights into energy demand patterns. [ABSTRACT FROM AUTHOR]
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- 2024
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24. Asynchronous event-triggered guaranteed cost control of uncertain 2-D Markov jump Roesser systems with actuator saturation.
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Liu, Jiazheng, Yang, Yang, and Song, Yaru
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This paper investigates the asynchronous event-triggered guaranteed cost control problem for two-dimensional Markov jump Roesser systems with parameter uncertainties and actuator saturation. The hidden Markov model is constructed to characterize the asynchronous phenomenon induced by the mode mismatch between the system and the controller, and a hidden Markov model-based event-triggered mechanism is adopted in controller design to save communication resources. The convex hull representation is employed to process saturated inputs. By using the quadratic Lyapunov function methods and linear matrix inequality techniques, some sufficient criteria are developed to guarantee the asymptotic stability of the addressed system with a guaranteed cost under three different boundary conditions. Finally, a convex optimization algorithm with linear matrix inequality constraints is proposed to design the optimal asynchronous event-triggered guaranteed cost controller, and a numerical example is considered to demonstrate its validity. [ABSTRACT FROM AUTHOR]
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- 2024
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25. RESEARCH ON THE CONSTRUCTION OF AI COMPOSITION SYSTEM BASED ON HMMS.
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Weijia YANG and Inho LEE
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ARTIFICIAL intelligence ,HIDDEN Markov models ,MUSICAL form ,COMPUTER science ,MARKOV processes - Abstract
Copyright of Yegah Musicology Journal / Yegah Müzikoloji Dergisi is the property of International Yegah Music Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2024
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26. Naivety dies with the calf: calf loss to human hunters imposes behavioral change in a long-lived but heavily harvested ungulate
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Lukas Graf, Henrik Thurfjell, Göran Ericsson, and Wiebke Neumann
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Alces alces ,Anti-predator behavior ,Hidden Markov Model ,Integrated Step Selection Function ,Sweden ,Biology (General) ,QH301-705.5 - Abstract
Abstract Background In prey, patterns of individual habitat selection and movement can be a consequence of an individuals’ anti-predator behavior. Adjustments of anti-predator behavior are important for prey to increase their survival. Hunters may alter the anti-predator behavior of prey. In long-lived animals, experience may cause behavioral changes during individuals’ lifetime, which may result in altered habitat selection and movement. Our knowledge of which specific events related to hunting activity induce behavioral changes in solitary living species is still limited. Methods We used offspring loss in a solitary and long-lived ungulate species, moose (Alces alces), as our model system. We investigated whether offspring loss to hunters induces behavioral changes in a species subjected to heavy human harvest but free from natural predation. To test for behavioral change in relation to two proxies for experience (calf fate and age), we combined movement data from 51 adult female moose with data on their offspring survival and female age. We tested for adjustments in females’ habitat selection and movement following calf harvest using Hidden Markov Models and integrated Step Selection Analysis to obtain behavioral state specific habitat selection coefficients. Results We found that females with a harvested calf modified habitat selection and movement during the following hunting season. Female moose selected for shorter distance to roads during the night, selected for shorter distance to forests and greater distance to human settlements following calf harvest than females who had not lost a calf. The survival of twins in a given hunting season was related to female age. Older females we more likely to have twins survive the hunting season. Conclusions Our findings suggest that losing offspring to human harvest imposes behavioral changes in a long-lived ungulate species, leading to adjustments in females' habitat selection and movement behavior, which may lower the risk of encountering hunters. In our study, female moose that experienced calf loss selected for lower distance to forest and selected for greater distance to human settlements during periods of high hunting pressure compared to females without the experience of calf loss during the previous hunting season. We interpret this as potential learning effects.
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- 2024
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27. Facial Recognition Using Hidden Markov Model and Convolutional Neural Network
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Muhammad Bilal, Saqlain Razzaq, Nirman Bhowmike, Azib Farooq, Muhammad Zahid, and Sultan Shoaib
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convolutional neural network ,hidden Markov model ,principal component analysis ,singular value decomposition ,Electronic computers. Computer science ,QA75.5-76.95 - Abstract
Face recognition (FR) uses a passive approach to person authentication that avoids face-to-face contact. Among different FR techniques, most FR approaches place little emphasis on reducing powerful cryptography and instead concentrate on increasing recognition rates. In this paper, we have proposed the Hidden Markov Model (HMM) and convolutional Neural Network (CNN) models for FR by using ORL and Yale datasets. Facial images from the given data sets are divided into 3 portions, 4 portions, 5 portions, and 6 portions corresponding to their respective HMM hidden states being used in the HMM model. Quantized levels of eigenvalues and eigenvector coefficients of overlapping blocks of facial images define the observation states of the HMM model. For image selection and rejection, a threshold is calculated using singular value decomposition (SVD). After training HMM on 3 states HMM, 4 states HMM, 5 states HMM, and 6 states HMM, the recognition accuracies are 96.5%, 98.5%, 98.5%, and 99.5%, respectively, on the ORL database and 90.6667%, 94.6667%, 94.6667%, and 94.6667% on the Yale database. The CNN model uses convolutional layers, a max-pooling layer, a flattening layer, a dense layer, and a dropout layer. Relu is used as the activation function in all layers except in the last layer, where softmax is used as the activation function. Cross entropy is used as a loss function, and we have used the Adam optimizer in our proposed algorithm. The proposed CNN model has given 100% training and testing accuracy on the ORL data set. While using the Yale data set, the CNN model has a training accuracy of 100% and a testing accuracy of 85.71%. In this paper, our proposed model showed that the HMM model is cost-effective with lesser accuracy, while the CNN model is more accurate as compared to HMM but has a higher computational cost.
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- 2024
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28. Finite mixture of hidden Markov models for tensor-variate time series data.
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Asilkalkan, Abdullah, Zhu, Xuwen, and Sarkar, Shuchismita
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The need to model data with higher dimensions, such as a tensor-variate framework where each observation is considered a three-dimensional object, increases due to rapid improvements in computational power and data storage capabilities. In this study, a finite mixture of hidden Markov model for tensor-variate time series data is developed. Simulation studies demonstrate high classification accuracy for both cluster and regime IDs. To further validate the usefulness of the proposed model, it is applied to real-life data with promising results. [ABSTRACT FROM AUTHOR]
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- 2024
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29. Dynamic functional connectivity and gene expression correlates in temporal lobe epilepsy: insights from hidden markov models
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Lu Qin, Qin Zhou, Yuting Sun, Xiaomin Pang, Zirong Chen, and Jinou Zheng
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Temporal lobe epilepsy ,Cognitive impairment ,Dynamic functional connectivity ,Hidden Markov model ,Resting-state functional magnetic resonance imaging ,Gene expression ,Medicine - Abstract
Abstract Backgroud Temporal lobe epilepsy (TLE) is associated with abnormal dynamic functional connectivity patterns, but the dynamic changes in brain activity at each time point remain unclear, as does the potential molecular mechanisms associated with the dynamic temporal characteristics of TLE. Methods Resting-state functional magnetic resonance imaging (rs-fMRI) was acquired for 84 TLE patients and 35 healthy controls (HCs). The data was then used to conduct HMM analysis on rs-fMRI data from TLE patients and an HC group in order to explore the intricate temporal dynamics of brain activity in TLE patients with cognitive impairment (TLE-CI). Additionally, we aim to examine the gene expression profiles associated with the dynamic modular characteristics in TLE patients using the Allen Human Brain Atlas (AHBA) database. Results Five HMM states were identified in this study. Compared with HCs, TLE and TLE-CI patients exhibited distinct changes in dynamics, including fractional occupancy, lifetimes, mean dwell time and switch rate. Furthermore, transition probability across HMM states were significantly different between TLE and TLE-CI patients (p
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- 2024
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30. Using lineups to evaluate goodness of fit of animal movement models
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John Fieberg, Smith Freeman, and Johannes Signer
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animal movement ,assumptions ,goodness of fit ,hidden Markov model ,integrated step‐selection analysis ,lineup ,Ecology ,QH540-549.5 ,Evolution ,QH359-425 - Abstract
Abstract Movement models are frequently fit to animal location data to understand how individuals respond to and interact with local environmental features. Several open‐source software packages are available for analysing animal movements and can facilitate parameter estimation, yet there are relatively few methods available for evaluating model goodness of fit. We describe how a simple graphical technique, the lineup protocol, can be used to evaluate goodness of fit of integrated step‐selection analyses and hidden Markov models, but the method can be applied much more broadly. We leverage the ability to simulate data from fitted models and demonstrate the approach using both an integrated step‐selection analysis and a hidden Markov model applied to fisher (Pekania pennanti) data. A variety of responses and movement metrics can be used to evaluate models, and the lineup protocol can be tailored to focus on specific model assumptions or movement features that are of primary interest. Although it is possible to evaluate statistical significance using a formal hypothesis test, the method can also be used in a more exploratory fashion (e.g. to explore variability in model behaviour across stochastic simulations or to identify areas where the model could be improved). We provide coded examples and vignettes to demonstrate the flexibility of the approach. We encourage movement ecologists to consider how their models will be applied when choosing appropriate graphical responses for evaluating goodness of fit.
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- 2024
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31. Dynamic functional connectivity and gene expression correlates in temporal lobe epilepsy: insights from hidden markov models.
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Qin, Lu, Zhou, Qin, Sun, Yuting, Pang, Xiaomin, Chen, Zirong, and Zheng, Jinou
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FUNCTIONAL magnetic resonance imaging , *HIDDEN Markov models , *TEMPORAL lobe epilepsy , *DEFAULT mode network , *LARGE-scale brain networks - Abstract
Backgroud: Temporal lobe epilepsy (TLE) is associated with abnormal dynamic functional connectivity patterns, but the dynamic changes in brain activity at each time point remain unclear, as does the potential molecular mechanisms associated with the dynamic temporal characteristics of TLE. Methods: Resting-state functional magnetic resonance imaging (rs-fMRI) was acquired for 84 TLE patients and 35 healthy controls (HCs). The data was then used to conduct HMM analysis on rs-fMRI data from TLE patients and an HC group in order to explore the intricate temporal dynamics of brain activity in TLE patients with cognitive impairment (TLE-CI). Additionally, we aim to examine the gene expression profiles associated with the dynamic modular characteristics in TLE patients using the Allen Human Brain Atlas (AHBA) database. Results: Five HMM states were identified in this study. Compared with HCs, TLE and TLE-CI patients exhibited distinct changes in dynamics, including fractional occupancy, lifetimes, mean dwell time and switch rate. Furthermore, transition probability across HMM states were significantly different between TLE and TLE-CI patients (p < 0.05). The temporal reconfiguration of states in TLE and TLE-CI patients was associated with several brain networks (including the high-order default mode network (DMN), subcortical network (SCN), and cerebellum network (CN). Furthermore, a total of 1580 genes were revealed to be significantly associated with dynamic brain states of TLE, mainly enriched in neuronal signaling and synaptic function. Conclusions: This study provides new insights into characterizing dynamic neural activity in TLE. The brain network dynamics defined by HMM analysis may deepen our understanding of the neurobiological underpinnings of TLE and TLE-CI, indicating a linkage between neural configuration and gene expression in TLE. [ABSTRACT FROM AUTHOR]
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- 2024
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32. Beyond Time-Homogeneity for Continuous-Time Multistate Markov Models.
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Kendall, Emmett B., Williams, Jonathan P., Hermansen, Gudmund H., Bois, Frederic, and Thanh, Vo Hong
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HIDDEN Markov models , *STOCHASTIC processes , *PARAMETER estimation , *DIFFERENTIAL equations , *ANALYTICAL solutions , *MARKOV processes - Abstract
Abstract– Multistate Markov models are a canonical parametric approach for data modeling of observed or latent stochastic processes supported on a finite state space. Continuous-time Markov processes describe data that are observed irregularly over time, as is often the case in longitudinal medical data, for example. Assuming that a continuous-time Markov process is time-homogeneous, a closed-form likelihood function can be derived from the Kolmogorov forward equations—a system of differential equations with a well-known matrix-exponential solution. Unfortunately, however, the forward equations do not admit an analytical solution for continuous-time, time-inhomogeneous Markov processes, and so researchers and practitioners often make the simplifying assumption that the process is piecewise time-homogeneous. In this article, we provide intuitions and illustrations of the potential biases for parameter estimation that may ensue in the more realistic scenario that the piecewise-homogeneous assumption is violated, and we advocate for a solution for likelihood computation in a truly time-inhomogeneous fashion. Particular focus is afforded to the context of multistate Markov models that allow for state label misclassifications, which applies more broadly to hidden Markov models (HMMs), and Bayesian computations bypass the necessity for computationally demanding numerical gradient approximations for obtaining maximum likelihood estimates (MLEs). Supplemental materials are available online. [ABSTRACT FROM AUTHOR]- Published
- 2024
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33. CW-PRED: Prediction of C-terminal surface anchoring sorting signals in bacteria and Archaea.
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Chatziargyri, Aikaterini G., Stasi, Evangelia A., Tsirigos, Konstantinos I., Litou, Zoi I., Iconomidou, Vassiliki A., and Bagos, Pantelis G.
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GRAM-positive bacteria , *BACTERIAL proteins , *GRAM-negative bacteria , *MARKOV processes , *SORTASES - Abstract
Sorting signals are crucial for the anchoring of proteins to the cell surface in archaea and bacteria. These proteins often feature distinct motifs at their C-terminus, cleaved by sortase or sortase-like enzymes. Gram-positive bacteria exhibit the LPXTGX consensus motif, cleaved by sortases, while Gram-negative bacteria employ exosortases recognizing motifs like PEP. Archaea utilize exosortase homologs known as archaeosortases for signal anchoring. Traditionally identification of such C-terminal sorting signals was performed with profile Hidden Markov Models (pHMMs). The Cell-Wall PREDiction (CW-PRED) method introduced for the first time a custom-made class HMM for proteins in Gram-positive bacteria that contain a cell wall sorting signal which begins with an LPXTG motif, followed by a hydrophobic domain and a tail of positively charged residues. Here we present a new and updated version of CW-PRED for predicting C-terminal sorting signals in Archaea, Gram-positive, and Gram-negative bacteria. We used a large training set and several model enhancements that improve motif identification in order to achieve better discrimination between C-terminal signals and other proteins. Cross-validation demonstrates CW-PRED's superiority in sensitivity and specificity compared to other methods. Application of the method in reference proteomes reveals a large number of potential surface proteins not previously identified. The method is available for academic use at http://195.251.108.230/apps.compgen.org/CW-PRED/ and as standalone software. [ABSTRACT FROM AUTHOR]
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- 2024
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34. Absolute direction in organelle movement.
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Plomer, Solveig, Meyer, Annika, Gebhardt, Philipp, Ernst, Theresa, Schleiff, Enrico, and Schneider, Gaby
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RANDOM walks , *ORGANELLES , *MARKOV processes , *CELL motility , *ANGLES , *SPEED - Abstract
In movement analysis, correlated random walk (CRW) models often use so‐called turning angles, which are measured relative to the previous movement direction. To segregate between different movement modes, hidden Markov models (HMMs) describe movements as piecewise stationary CRWs in which the distributions of turning angles and step sizes depend on the underlying state. This typically allows for the segregation of movement modes that show different movement speeds. We show that in some cases, it may be interesting to investigate absolute angles, that is, biased random walks (BRWs) instead of turning angles. In particular, while discrimination between states in the turning angle setting can only rely on movement speed, models with absolute angles can be used to discriminate between sections of different movement directions. A preprocessing algorithm is provided that enables the analysis of absolute angles in the existing R package moveHMM. In a data set of movements of cell organelles, models using not the turning angle but the absolute angle could capture interesting additional properties. Goodness‐of‐fit was increased for HMMs with absolute angles, and HMMs with absolute angles tended to choose a higher number of states, suggesting the existence and relevance of prominent directional changes in the present data set. These results suggest that models with absolute angles can provide important information in the analysis of movement patterns if the existence and frequency of directional changes is of biological importance. [ABSTRACT FROM AUTHOR]
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- 2024
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35. Enhancing Speech Assistive Systems Through a Sequence-to-Vector Representation Approach for Disordered Speech.
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Vishnika Veni, S. and Santhi, B.
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HIDDEN Markov models , *SPEECH perception , *MACHINE learning , *SPEECH , *SUPPORT vector machines - Abstract
Speech assistive system for people with neuro disorders is a highly challenging task till date. Any kind of neuro cognitive disability affects the speech production mechanism that leads to speech impairment. Representation learning methods have recently emerged to improve the outcome of machine learning algorithms. In case of complex recognition tasks such as disordered speech recognition, learning compact and efficient representations for disordered speech utterances is important. Recent deep learning-based architectures need sufficiently large amount of impaired speech samples which are tedious with respect to neurologically disabled people. In this work, we focus on proposing a representation learning approach that uses traditional sequential model such as Hidden Markov Model (HMM) which works moderately well with small amount of impaired speech data. We propose a novel sequence to vector-based HMM State Sequence (HMM-SS) approach which is very compact and has proved to be an efficient representation for disordered speech utterances. The efficiency of the proposed HMM-SS approach is assessed using four datasets, namely 50 words of TORGO, 100-common words dataset of the UA-SPEECH, 50 help-seeking words and 100-common words of Impaired speech corpus in Tamil corpus. The proposed approach outperforms the baseline HMM, DNN-HMM and a recent state-of-the-art approach for all four datasets. The discriminative ability and the compactness of the proposed representation proved effective for disordered speech recognition. [ABSTRACT FROM AUTHOR]
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- 2024
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36. Comparable foraging effort and habitat use between two geographically proximate tropical seabird colonies.
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Trevail, Alice M., Vallocchia, Sonia, Nicoll, Malcolm A. C., Carr, Peter, Votier, Stephen C., Wood, Hannah, and Freeman, Robin
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COLONIAL birds , *MARINE parks & reserves , *HABITAT selection , *OCEAN temperature , *ANT algorithms , *SPATIAL ecology , *HABITATS - Abstract
Effective seabird conservation requires understanding their marine spatial ecology. Tracking can reveal details of their foraging ecology and habitat use, as well as the suitability of marine protected areas for at-sea conservation, but results are often regionally specific. Here we characterised the foraging behaviour of tropical breeding brown boobies Sula leucogaster in the Chagos Archipelago, Western Indian Ocean, and tested habitat requirements. GPS tracking of thirteen individuals from two colonies, located 142 km apart on the same atoll (Great Chagos Bank), showed similar foraging effort and habitat preferences despite differences in season and breeding stage. Brown boobies from both tracked populations foraged close to the colony along the atoll shelf edge, avoiding deep oceanic areas and shallow waters of the Great Chagos Bank atoll, but within the Chagos Archipelago Marine Protected Area. Sea-level height anomaly and sea surface temperature were important foraging predictors at both sites, although birds experienced distinct environmental conditions between colonies. These results suggest that while brown boobies have colony-specific at-sea foraging areas, similarities in habitat drivers of distribution and foraging behaviour can inform predictions of distributions at other colonies within the archipelago, with important benefits for at-sea conservation efforts. [ABSTRACT FROM AUTHOR]
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- 2024
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37. Evidence for Mood Instability in Patients With Bipolar Disorder: Applying Multilevel Hidden Markov Modeling to Intensive Longitudinal Ecological Momentary Assessment Data.
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Mildiner Moraga, Sebastian, Bos, Fionneke M., Doornbos, Bennard, Bruggeman, Richard, van der Krieke, Lian, Snippe, Evelien, and Aarts, Emmeke
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HIDDEN Markov models , *MOOD (Psychology) , *BIPOLAR disorder , *MULTILEVEL models , *MARKOV processes , *ECOLOGICAL momentary assessments (Clinical psychology) - Abstract
Bipolar disorder (BD) is a chronic psychiatric condition characterized by large episodic changes in mood and energy. Recently, BD has been proposed to be conceptualized as chronic cyclical mood instability, as opposed to the traditional view of alternating discrete episodes with stable periods in-between. Recognizing this mood instability may improve care and call for high-frequency measures coupled with advanced statistical models. To uncover empirically derived mood states, a multilevel hidden Markov model (HMM) was applied to 4-month ecological momentary assessment data in 20 patients with BD, yielding ∼9,820 assessments in total. Ecological momentary assessment data comprised self-report questionnaires (5 × daily) measuring manic and depressive constructs. Manic and depressive symptoms were also assessed weekly using the Altman Self-Rating Mania Scale and the Quick Inventory for Depressive Symptomatology Self-Report. Alignment between HMM-uncovered momentary mood states and weekly questionnaires was assessed with a multilevel linear model. HMM uncovered four mood states: neutral, elevated, mixed, and lowered, which aligned with weekly symptom scores. On average, patients remained <25 hr in one state. In almost half of the patients, mood instability was observed. Switching between mood states, three patterns were identified: patients switching predominantly between (a) neutral and lowered states, (b) neutral and elevated states, and (c) mixed, elevated, and lowered states. In all, elevated and lowered mood states were interspersed by mixed states. The results indicate that chronic mood instability is a key feature of BD, even in "relatively" euthymic periods. This should be considered in theoretical and clinical conceptualizations of the disorder. General Scientific Summary: The article investigates bipolar disorder with advanced statistical methods and adds evidence challenging the traditional view of alternating discrete mood episodes with stable periods in-between. Instead, it suggests that chronic mood instability may be a significant aspect of bipolar disorder and calls for high-frequency assessments using advanced statistical models to better understand and improve care for individuals with the disorder. [ABSTRACT FROM AUTHOR]
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- 2024
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38. An outlier detection method based on the hidden Markov model and copula for wireless sensor networks.
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Dogmechi, Sina, Torabi, Zeinab, and Daneshpour, Negin
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HIDDEN Markov models , *WIRELESS sensor networks , *MARKOV processes , *MODEL theory , *DATA distribution - Abstract
Some of the collected data by wireless sensor networks (WSNs) often digress from the normal pattern of the set and are called the 'outliers' or 'anomalies'. These outlier data are usually derived from an error that can be due to the constraints of sensor nodes such as problems in the processing unit, power supply, and component failure or an event occurring at the development site of sensor nodes, including the earthquake or flood, affecting the quality of the collected data and their reliability for decision making. In this work, a method is proposed for detecting outlier data in networks based on the hidden Markov model and the copula theory. Copula was used because of its ability to deal with multivariate sets and its unlimitedness in such a way that it required no assumption about data distribution, and Markov has been applied due to its good performance in forecasting. The results of evaluations on the actual data from the Intel laboratory represent the efficiency of the proposed method. Bases on the performance evaluations of the proposed method, in comparison with a relatively new work leading to good results. [ABSTRACT FROM AUTHOR]
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- 2024
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39. Using multiple scales of movement to highlight risk–reward strategies of coyotes (Canis latrans) in mixed‐use landscapes.
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Van Scoyoc, Amy, Calhoun, Kendall L., and Brashares, Justin S.
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PUMAS ,NATURAL selection ,MARKOV processes ,AGRICULTURE ,PREDATORY animals ,HABITAT selection ,HABITATS - Abstract
Many wildlife species vary habitat selection across space, time, and behavior to maximize rewards and minimize risk. Multi‐scale research approaches that identify variation in wildlife habitat selection can highlight not only habitat preferences and risk tolerance but also movement strategies that afford coexistence or cause conflict with humans. Here, we examined how anthropogenic and natural features influenced coyote (Canis latrans) habitat selection in a mixed‐use, agricultural landscape in Mendocino County, California, USA. We used resource selection functions and hidden Markov models to test whether coyote selection for anthropogenic and natural features varied by time of day or by behavioral state (resting, foraging, and traveling). We found that coyotes avoided development, but, contrary to our expectations, coyotes selected for roads, agriculture, and areas with risk of human encounter and rifle use regardless of diel period or behavioral state. While traveling, coyotes increased selection for roads and avoided ruggedness, indicating that unpaved roads may enhance connectivity for coyotes in mixed‐use landscapes. Finally, we found that coyotes selected for mountain lion habitat when resting and at night, signifying that risk from natural predators was not a factor in habitat selection at coarse scales. Coyote habitat selection for places and times associated with human activity, without variation across scales, signals a potential for conflict if coyotes are perceived by people as a nuisance. [ABSTRACT FROM AUTHOR]
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- 2024
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40. 基于路网复杂度分区的轨迹分段地图匹配方法.
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王庆庆, 郭杜杜, 王洋, 周飞, and 秦音
- Abstract
Copyright of Journal of Computer Engineering & Applications is the property of Beijing Journal of Computer Engineering & Applications Journal Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2024
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- View/download PDF
41. Flexible modeling of headache frequency fluctuations in migraine with hidden Markov models.
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Dumkrieger, Gina M., Ishii, Ryotaro, and Goadsby, Peter J.
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HIDDEN Markov models , *MIGRAINE , *HEADACHE , *DIARY (Literary form) - Abstract
Objective Background Methods Results Conclusion To explore hidden Markov models (HMMs) as an approach for defining clinically meaningful headache‐frequency‐based groups in migraine.Monthly headache frequency in patients with migraine is known to vary over time. This variation has not been completely characterized and is not well accounted for in the classification of individuals as having chronic or episodic migraine, a diagnosis with potentially significant impacts on the individual. This study investigated variation in reported headache frequency in a migraine population and proposed a model for classifying individuals by frequency while accounting for natural variation.The American Registry for Migraine Research (ARMR) was a longitudinal multisite study of United States adults with migraine. Study participants completed quarterly questionnaires and daily headache diaries. A series of HMMs were fit to monthly headache frequency data calculated from the diary data of ARMR.Changes in monthly headache frequency tended to be small, with 47% of transitions resulting in a change of 0 or 1 day. A substantial portion (24%) of months reflected daily headache with individuals ever reporting daily headache likely to consistently report daily headache. An HMM with four states with mean monthly headache frequency emissions of 3.52 (95% Prediction Interval [PI] 0–8), 10.10 (95% PI 4–17), 20.29 (95% PI 12–28), and constant 28 days/month had the best fit of the models tested. Of sequential month‐to‐month headache frequency transitions, 12% were across the 15‐headache days chronic migraine cutoff. Under the HMM, 38.7% of those transitions involved a change in the HMM state, and the remaining 61.3% of the time, a change in chronic migraine classification was not accompanied by a change in the HMM state.A divide between the second and third states of this model aligns most strongly with the current episodic/chronic distinction, although there is a meaningful overlap between the states that supports the need for flexibility. An HMM has appealing properties for classifying individuals according to their headache frequency while accounting for natural variation in frequency. This empirically derived model may provide an informative classification approach that is more stable than the use of a single cutoff value. [ABSTRACT FROM AUTHOR]
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- 2024
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42. Artificial intelligence tools for the identification of antibiotic resistance genes.
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Olatunji, Isaac, Bardaji, Danae Kala Rodriguez, Miranda, Renata Rezende, Savka, Michael A., and Hudson, André O.
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DRUG resistance in bacteria ,ARTIFICIAL intelligence ,IDENTIFICATION ,GENETIC mutation ,FEATURE selection ,BACTERIAL diseases - Abstract
The fight against bacterial antibiotic resistance must be given critical attention to avert the current and emerging crisis of treating bacterial infections due to the inefficacy of clinically relevant antibiotics. Intrinsic genetic mutations and transferrable antibiotic resistance genes (ARGs) are at the core of the development of antibiotic resistance. However, traditional alignment methods for detecting ARGs have limitations. Artificial intelligence (AI) methods and approaches can potentially augment the detection of ARGs and identify antibiotic targets and antagonistic bactericidal and bacteriostatic molecules that are or can be developed as antibiotics. This review delves into the literature regarding the various AI methods and approaches for identifying and annotating ARGs, highlighting their potential and limitations. Specifically, we discuss methods for (1) direct identification and classification of ARGs from genome DNA sequences, (2) direct identification and classification from plasmid sequences, and (3) identification of putative ARGs from feature selection. [ABSTRACT FROM AUTHOR]
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- 2024
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43. Hidden Markov model with Pitman-Yor priors for probabilistic topic model.
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Guo, Jianjie, Guo, Lin, Xu, Wenchao, and Zhang, Haibin
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WORD frequency , *NATURAL languages , *HIDDEN Markov models , *PARAMETRIC modeling , *STATISTICAL models - Abstract
Abstract.Empirical studies of natural language have demonstrated that word frequencies follow power law distributions. However, standard statistical models often fail to capture this property. The Pitman-Yor process (PYP), a Bayesian non parametric model capable of generating power law distributions, has been widely used in probabilistic topic models to handle data with an infinite number of components. However, existing PYP topic models rarely account for the relationships between topics. Hidden Markov models (HMMs) are popular models for modeling topic relationships. To address this limitation, we propose a probabilistic topic model that combines HMM with Pitman-Yor priors. The posterior inference was performed by using variational Bayes methods. We applied our method to text categorization and compared it with two related topic models: the hidden Markov topic model and hierarchical PYP topic model. [ABSTRACT FROM AUTHOR]
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- 2024
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44. Brain state dynamics differ between eyes open and eyes closed rest.
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Ingram, Brandon T., Mayhew, Stephen D., and Bagshaw, Andrew P.
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MAGNETIC resonance imaging , *HIDDEN Markov models , *FUNCTIONAL connectivity , *FUNCTIONAL magnetic resonance imaging - Abstract
The human brain exhibits spatio‐temporally complex activity even in the absence of external stimuli, cycling through recurring patterns of activity known as brain states. Thus far, brain state analysis has primarily been restricted to unimodal neuroimaging data sets, resulting in a limited definition of state and a poor understanding of the spatial and temporal relationships between states identified from different modalities. Here, we applied hidden Markov model (HMM) to concurrent electroencephalography‐functional magnetic resonance imaging (EEG‐fMRI) eyes open (EO) and eyes closed (EC) resting‐state data, training models on the EEG and fMRI data separately, and evaluated the models' ability to distinguish dynamics between the two rest conditions. Additionally, we employed a general linear model approach to identify the BOLD correlates of the EEG‐defined states to investigate whether the fMRI data could be used to improve the spatial definition of the EEG states. Finally, we performed a sliding window‐based analysis on the state time courses to identify slower changes in the temporal dynamics, and then correlated these time courses across modalities. We found that both models could identify expected changes during EC rest compared to EO rest, with the fMRI model identifying changes in the activity and functional connectivity of visual and attention resting‐state networks, while the EEG model correctly identified the canonical increase in alpha upon eye closure. In addition, by using the fMRI data, it was possible to infer the spatial properties of the EEG states, resulting in BOLD correlation maps resembling canonical alpha‐BOLD correlations. Finally, the sliding window analysis revealed unique fractional occupancy dynamics for states from both models, with a selection of states showing strong temporal correlations across modalities. Overall, this study highlights the efficacy of using HMMs for brain state analysis, confirms that multimodal data can be used to provide more in‐depth definitions of state and demonstrates that states defined across different modalities show similar temporal dynamics. [ABSTRACT FROM AUTHOR]
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- 2024
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45. Intelligent prediction method of urban road traffic congestion based on knowledge graph technology.
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Liu, T. and Su, H. D.
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K-means clustering , *INTELLIGENT transportation systems , *CITY traffic , *TRAFFIC congestion , *KNOWLEDGE graphs , *HIDDEN Markov models , *STANDARD deviations - Abstract
The intelligent prediction of urban road traffic congestion is of great significance for improving traffic efficiency, reducing congestion, and optimizing resource allocation, thereby improving the overall mobility and quality of life of the city. In order to overcome the shortcomings of traditional prediction methods for urban road traffic congestion, such as poor prediction accuracy and long prediction time, an intelligent prediction method of urban road traffic congestion based on knowledge graph technology is proposed in this paper. Urban road data are collected in a static and dynamic way, and urban road traffic data are clustered by improved K-means clustering algorithm. Using stepwise regression method to repair urban road traffic data, combining knowledge graph technology to mine the influencing factors of urban road traffic congestion, and combining hidden Markov model to realize intelligent prediction of urban road traffic congestion. The experimental results show that the average absolute error of this method is 0.378, the mean root mean square error is 1.284, and the time formula of urban road traffic congestion intelligent prediction is below 0.32s. It prove that new the prediction method has the characteristics of high precision and high efficiency. [ABSTRACT FROM AUTHOR]
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- 2024
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46. Experimental Methodology to Optimize Power Flow in Utility Grid with Integrated Renewable Energy and Storage Devices Using Hidden Markov Model.
- Author
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Karthik, T. S., Kamalakkannan, D., Murugesan, S., Patra, Jyoti Prasad, Walid, Md. Abul Ala, Chenchireddy, Kalagotla, A, Syed Musthafa, and Jagadish Kumar, B.
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HIDDEN Markov models , *RENEWABLE energy sources , *ELECTRIC utilities , *ENERGY storage , *DEEP reinforcement learning , *ELECTRICAL load , *MICROGRIDS - Abstract
A continuous energy supply to the load side is required by modern power systems. This calls for a sound understanding of how to forecast load demand in the present and the future with the least degree of inaccuracy. Typically, a sequential method with two steps—forecasting and optimization—is used to derive judgments from data. For achieving this goal, optimized power flow is focused in this paper through load forecasting, mode selection, and optimization of power forecasting. Firstly, load forecasting is implemented using time series, and economic and weather-related information for the different consumer's load. Then mode selection is implemented using Hidden Markov Model that determines the requested load for grid-connected or RES mode. When composite RES is developed, the percentage of serviced load rises as more renewable energy sources are added. Following the implementation of the consumer load and mode selection, optimization is used to improve the power flow. The empirical findings show enhanced prescriptive performance when compared to answers found in single- and multi-household contexts. Also, we offer insightful information on how explaining performance is described. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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47. Understanding Human Cognition Through Computational Modeling.
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Hsiao, Janet Hui‐wen
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ARTIFICIAL neural networks , *HIDDEN Markov models , *COGNITION , *ARTIFICIAL intelligence , *COGNITIVE neuroscience - Abstract
One important goal of cognitive science is to understand the mind in terms of its representational and computational capacities, where computational modeling plays an essential role in providing theoretical explanations and predictions of human behavior and mental phenomena. In my research, I have been using computational modeling, together with behavioral experiments and cognitive neuroscience methods, to investigate the information processing mechanisms underlying learning and visual cognition in terms of perceptual representation and attention strategy. In perceptual representation, I have used neural network models to understand how the split architecture in the human visual system influences visual cognition, and to examine perceptual representation development as the results of expertise. In attention strategy, I have developed the Eye Movement analysis with Hidden Markov Models method for quantifying eye movement pattern and consistency using both spatial and temporal information, which has led to novel findings across disciplines not discoverable using traditional methods. By integrating it with deep neural networks (DNN), I have developed DNN+HMM to account for eye movement strategy learning in human visual cognition. The understanding of the human mind through computational modeling also facilitates research on artificial intelligence's (AI) comparability with human cognition, which can in turn help explainable AI systems infer humans' belief on AI's operations and provide human‐centered explanations to enhance human−AI interaction and mutual understanding. Together, these demonstrate the essential role of computational modeling methods in providing theoretical accounts of the human mind as well as its interaction with its environment and AI systems. In this paper, I summarize my research in visual cognition, language processing, and explainable AI to demonstrate the essential role of computational modeling methods in providing theoretical accounts of the human mind as well as its interaction with its environment and AI systems. [ABSTRACT FROM AUTHOR]
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- 2024
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48. 1-Dodecanol as Potential Inducer for the FAO1 Promoter (PFAO1) in Morphologically Identified Meyerozyma guilliermondii Strain SO.
- Author
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Mahyon, Nur Iznida, Sabri, Suriana, Jijew, George Crisol, Salleh, Abu Bakar, Leow, Thean Chor, Lim, Si Jie, Oslan, Siti Nur Hazwani, Masomian, Malihe, and Oslan, Siti Nurbaya
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SCANNING transmission electron microscopy , *BIOCHEMICAL substrates , *PICHIA pastoris , *PROTEIN structure , *PROTEIN expression - Abstract
Alcohol oxidase (AOX) oxidizes alcohols to produce carbonyl compounds and peroxides. Its promoter (PAOX1) is widely used in methylotrophic yeasts. A promising yeast expression system (Pichia sp. strain SO) was developed for bacterial lipase expression regulated by PAOX1 of Komagataella phaffii (previously known as Pichia pastoris). However, its unidentified AOX gene and the protein structure have deterred the search for the best inducer. This study was aimed to identify the yeast species and determine the best inducer for PAOX1 upregulation using in silico AOX protein analysis. Morphological (scanning and transmission electron microscopies) and carbon assimilation analyses confirmed isolate SO as Meyerozyma guilliermondii (previously known as Pichia guilliiermondii). Using Hidden-Markov model and degenerate PCR, the LCAO gene (2091 bp) was discovered in M. guilliermondii strain SO. The enzyme, MgFAO1 shared 14% similarity to K. phaffii AOX1 protein (KpAOX1). Molecular docking of MgFAO1 three-dimensional structure predicted using AlphaFold2 showed its preference toward long-chain 1-dodecanol as the substrate unlike KpAOX1 (short-chain methanol). While the alcohol-binding pocket in MgFAO1 was more hydrophobic compared to KpAOX1, 1-dodecanol could be a better inducer for protein expression in M. guilliermondii strain SO. Thus, in silico pipeline employed in this study can help identify homologous proteins in other expression hosts and their preferred substrates for promoter upregulation. However, the computational analyses were merely predictions and further wet-lab validation is required. Yet, this strategy allows cost-efficient screening of potential inducers for microbe-based protein production in the industries, reducing the production cost and offering cheaper options for consumers. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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49. Detection of Track Bed Defects Based on Fibre Optic Sensor Signals and an Improved Hidden Markov Model.
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Li, Wenya, He, Lang, Li, Zhengying, and Wan, Yuan
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HIDDEN Markov models ,AREA measurement ,MARKOV processes ,FEATURE extraction ,OPTICAL sensors ,POWER spectra - Abstract
Railway track bed defects affect the normal operation of trains and pose great safety risks. In order to detect such issues early, we developed a railway track bed defect detection method which uses optical fibre sensors and an improved HMM (hidden Markov model) to detect the signals collected by a DAS (distributed acoustic sensing) system. First, by analysing the physical process of train operation and determining the number of hidden states, a waveform segmentation method based on average amplitude was used to solve the problem of unequal signal lengths. Second, an adaptive power spectrum energy ratio calculation method was employed to extract track fault features, a set of which was constructed by combining various quantity features. Then, normal and abnormal models were trained according to the sensor measurement area. Finally, the probability of detecting the signal with each model was compared to determine whether the signal was abnormal. Experiments were conducted to compare the applicability of the waveform segmentation method and the feature extraction method. The results show that the HMM based on both waveform segmentation and track bed defect feature sets had the highest recognition rate, the lowest number of false detection areas, and a greater impact on the signal in the early development stage of track bed defects. The proposed method, therefore, has strong recognition ability, which makes it suitable for track bed defect detection. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. HMM-Based Blockchain Visual Automatic Deployment System.
- Author
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Yi, Junkai, Wang, Jin, Tan, Lingling, and Yuan, Taifu
- Subjects
BLOCKCHAINS ,HIDDEN Markov models - Abstract
The traditional blockchain deployment process is too complicated and has high technical requirements for blockchain deployers. Deploying a blockchain requires building a complex software-dependent environment, being able to use Linux commands for cumbersome parameter configurations, as well as the need to consider whether the hardware meets the requirements for running a blockchain. To address these current challenges in blockchain deployment both domestically and internationally, a web-based automatic deployment system with an interactive front-end and back-end has been developed. This system streamlines the process by automatically configuring and deploying blockchains while providing deployers with a graphical interface to monitor the entire deployment procedure. Meanwhile, in order to improve the efficiency of blockchain deployment, a Hidden Markov Model has been designed for blockchain deployment, which can predict the best deployment method for blockchain deployment under the current software environment. As one of the excellent blockchain platforms in China, Chainmaker has the outstanding features of independent control, flexible assembly, software and hardware integration, open source, and openness. The system takes Chainmaker as an experimental object and after a lot of tests, it can easily build a blockchain network on the server. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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