UNRAVELING MARKOV PROCESSES IN MOVEMENT PATTERNS OF INDICATOR SPECIES IN RESPONSE TO CHEMICAL STRESSORS

2011 ◽  
Vol 25 (12n13) ◽  
pp. 1143-1149 ◽  
Author(s):  
TUYEN VAN NGUYEN ◽  
YUEDAN LIU ◽  
IL-HYO JUNG ◽  
TAE-SOO CHON ◽  
SANG-HEE LEE
Keyword(s):  
Markov Processes ◽  
Transition Probability ◽  
Movement Patterns ◽  
Critical Issue ◽  
Transition Probability Matrix ◽  
Behavioral Changes ◽  
Environmental Stressors ◽  
Biological Responses ◽  
Low Concentrations ◽  
Before And After

Revealing biological responses of organisms in responding to environmental stressors is the critical issue in contemporary ecological sciences. Markov processes in behavioral data were unraveled by utilizing the hidden Markov model (HMM). Individual organisms of daphnia (Daphnia magna) and zebrafish (Danio rerio) were exposed to diazinon at low concentrations. The transition probability matrix (TPM) and the emission probability matrix (EPM) were accordingly estimated by training with the HMM and were verified before and after the treatments with 10-6 tolerance in 103 iterations. Structured property in behavioral changes was accordingly revealed to characterize dynamic processes in movement patterns. Parameters and sequences produced through the HMM training could be a suitable means of monitoring toxic chemicals in environment.

scholarly journals Steganalysis of Quantization Index Modulation Steganography in G.723.1 Codec

2020 ◽  
Vol 12 (1) ◽  
pp. 17
Author(s):  
Zhijun Wu ◽  
Rong Li ◽  
Panpan Yin ◽  
Changliang Li
Keyword(s):  
Transition Probability ◽  
Principal Component ◽  
Transition Probability Matrix ◽  
Support Vector ◽  
Quantization Index Modulation ◽  
Distribution Probability ◽  
Before And After ◽  
Security Of Network ◽  
Index Value ◽  
Index Modulation

Steganalysis is used for preventing the illegal use of steganography to ensure the security of network communication through detecting whether or not secret information is hidden in the carrier. This paper presents an approach to detect the quantization index modulation (QIM) of steganography in G.723.1 based on the analysis of the probability of occurrence of index values before and after steganography and studying the influence of adjacent index values in voice over internet protocol (VoIP). According to the change of index value distribution characteristics, this approach extracts the distribution probability matrix and the transition probability matrix as feature vectors, and uses principal component analysis (PCA) to reduce the dimensionality. Through a large amount of sample training, the support vector machine (SVM) is designed as a classifier to detect the QIM steganography. The speech samples with different embedding rates and different durations were tested to verify their impact on the accuracy of the steganalysis. The experimental results show that the proposed approach improves the accuracy and reliability of the steganalysis.

Estimation of State Transition Probabilities in Asynchronous Vector Markov Processes

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Waleed A. Farahat ◽  
H. Harry Asada
Keyword(s):  
Population Dynamics ◽  
Markov Processes ◽  
State Transition ◽  
Transition Probabilities ◽  
Transition Probability ◽  
Transition Probability Matrix ◽  
Sampling Schemes ◽  
Markov Chain Sampling ◽  
Bayesian Formulation ◽  
Wide Range

Vector Markov processes (also known as population Markov processes) are an important class of stochastic processes that have been used to model a wide range of technological, biological, and socioeconomic systems. The dynamics of vector Markov processes are fully characterized, in a stochastic sense, by the state transition probability matrix P. In most applications, P has to be estimated based on either incomplete or aggregated process observations. Here, in contrast to established methods for estimation given aggregate data, we develop Bayesian formulations for estimating P from asynchronous aggregate (longitudinal) observations of the population dynamics. Such observations are common, for example, in the study of aggregate biological cell population dynamics via flow cytometry. We derive the Bayesian formulation, and show that computing estimates via exact marginalization are, generally, computationally expensive. Consequently, we rely on Monte Carlo Markov chain sampling approaches to estimate the posterior distributions efficiently. By explicitly integrating problem constraints in these sampling schemes, significant efficiencies are attained. We illustrate the algorithm via simulation examples and show that the Bayesian estimation schemes can attain significant advantages over point estimates schemes such as maximum likelihood.

scholarly journals Cellular Statistical Models of Broken Cloud Fields. Part III: Markovian Properties

2017 ◽  
Vol 74 (9) ◽  
pp. 2921-2935 ◽  
Author(s):  
Mikhail D. Alexandrov ◽  
Alexander Marshak
Keyword(s):  
Distribution Function ◽  
Probability Distribution ◽  
Markov Processes ◽  
Statistical Models ◽  
Probability Distribution Function ◽  
Transition Probability ◽  
Transition Probability Matrix ◽  
Cloud Fraction ◽  
Future Studies ◽  
The Third

Abstract In the third part of the “Cellular Statistical Models of Broken Cloud Fields” series the cloud statistics formalism developed in the first two parts is interpreted in terms of the theory of Markov processes. The master matrix introduced in this study is a unifying generalization of both the cloud fraction probability distribution function (PDF) and the Markovian transition probability matrix. To illustrate the new concept, the master matrix is used for computation of the moments of the cloud fraction PDF—in particular, the variance—which until now has not been analytically derived in the framework of the authors’ previous work. This paper also serves as a bridge to the proposed future studies of the effects of sampling and averaging on satellite-based cloud masks.

Uncertainties Associated with Assessing the Risk of an Endocrine Active Substance in the Canadian Environment

2001 ◽  
Vol 36 (2) ◽  
pp. 319-330 ◽  
Author(s):  
Mark Servos ◽  
Don Bennie ◽  
Kent Burnison ◽  
Philippa Cureton ◽  
Nicol Davidson ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Endocrine Disruption ◽  
Endocrine System ◽  
Problem Formulation ◽  
Normal Function ◽  
Weight Of Evidence ◽  
Biological Responses ◽  
Low Concentrations ◽  
Multigenerational Effects

Abstract A number of biological responses and multigenerational effects, mediated through the disruption of endocrine systems, have been observed in biota exposed to relatively low concentrations of environmental contaminants. These types of responses need to be considered within a weight of evidence approach in our risk assessment and risk management frameworks. However, including endocrine responses in an environmental risk assessment introduces a number of uncertainties that must be considered. A risk assessment of nonylphenol and nonylphenol polyethoxylates (NP/NPE) is used as a case study to demonstrate the sources and magnitude of some of the uncertainties associated with using endocrine disruption as an assessment endpoint. Even with this relatively well studied group of substances, there are substantial knowledge gaps which contribute to the overall uncertainties, limiting the interpretation within the risk assessment. The uncertainty of extrapolating from in vitro or biochemical responses to higher levels of organization or across species is not well understood. The endocrine system is very complex and chemicals can interact or interfere with the normal function of endocrine systems in a number of ways (e.g., receptors, hormones) which may or may not result in an adverse responses in the whole organism. Using endocrine responses can lead to different conclusions than traditional endpoints due to a variety of factors, such as differences in relative potencies of chemicals for specific endpoints (e.g., receptor binding versus chronic toxicity). The uncertainties can also be considerably larger and the desirability of using endocrine endpoints should be carefully evaluated. Endocrine disruption is a mode of action and not a functional endpoint and this needs to be considered carefully in the problem formulation stage and the interpretation of the weight of evidence.

On calculating extinction probabilities for branching processes in random environments

1969 ◽  
Vol 6 (03) ◽  
pp. 478-492 ◽  
Author(s):  
William E. Wilkinson
Keyword(s):  
Generating Functions ◽  
Infinite Sequence ◽  
Branching Processes ◽  
Transition Probability ◽  
Transition Probability Matrix ◽  
Random Environments ◽  
Real Numbers ◽  
Discrete Time Markov Chain ◽  
Extinction Probabilities ◽  
Image Position

Consider a discrete time Markov chain {Zn } whose state space is the non-negative integers and whose transition probability matrix ║Pij ║ possesses the representation where {Pr }, r = 1,2,…, is a finite or denumerably infinite sequence of non-negative real numbers satisfying , and , is a corresponding sequence of probability generating functions. It is assumed that Z 0 = k, a finite positive integer.

scholarly journals Twelve Years of the Italian Program to Enhance Relational and Communication Skills (PERCS)

2021 ◽  
Vol 18 (2) ◽  
pp. 439
Author(s):  
Lidia Borghi ◽  
Elaine C. Meyer ◽  
Elena Vegni ◽  
Roberta Oteri ◽  
Paolo Almagioni ◽  
...  
Keyword(s):  
Communication Skills ◽  
Repeated Measures ◽  
Behavioral Changes ◽  
Chi Square ◽  
Future Directions ◽  
Public And Private ◽  
Learner Centered ◽  
Difficult Conversations ◽  
Booster Sessions ◽  
Before And After

To describe the experience of the Italian Program to Enhance Relations and Communication Skills (PERCS-Italy) for difficult healthcare conversations. PERCS-Italy has been offered in two different hospitals in Milan since 2008. Each workshop lasts 5 h, enrolls 10–15 interdisciplinary participants, and is organized around simulations and debriefing of two difficult conversations. Before and after the workshops, participants rate their preparation, communication, relational skills, confidence, and anxiety on 5-point Likert scales. Usefulness, quality, and recommendation of the program are also assessed. Descriptive statistics, t-tests, repeated-measures ANOVA, and Chi-square were performed. A total of 72 workshops have been offered, involving 830 interdisciplinary participants. Participants reported improvements in all the dimensions (p < 0.001) without differences across the two hospitals. Nurses and other professionals reported a greater improvement in preparation, communication skills, and confidence, compared to physicians and psychosocial professionals. Usefulness, quality, and recommendation of PERCS programs were highly rated, without differences by discipline. PERCS-Italy proved to be adaptable to different hospital settings, public and private. After the workshops, clinicians reported improvements in self-reported competencies when facing difficult conversations. PERCS-Italy’s sustainability is based on the flexible format combined with a solid learner-centered approach. Future directions include implementation of booster sessions to maintain learning and the assessment of behavioral changes.

Further enhancement on H∞ sliding mode control design for singular Markovian jump systems with partly known transition probabilities

2021 ◽  
pp. 107754632198920
Author(s):  
Zeinab Fallah ◽  
Mahdi Baradarannia ◽  
Hamed Kharrati ◽  
Farzad Hashemzadeh
Keyword(s):  
Transition Probabilities ◽  
Sliding Mode ◽  
Transition Probability ◽  
Transition Probability Matrix ◽  
Linear Matrix ◽  
Sliding Mode Controller ◽  
Sliding Surface ◽  
Markovian Jump ◽  
Markovian Jump System ◽  
Singular Markovian Jump Systems

This study considers the designing of the H ∞ sliding mode controller for a singular Markovian jump system described by discrete-time state-space realization. The system under investigation is subject to both matched and mismatched external disturbances, and the transition probability matrix of the underlying Markov chain is considered to be partly available. A new sufficient condition is developed in terms of linear matrix inequalities to determine the mode-dependent parameter of the proposed quasi-sliding surface such that the stochastic admissibility with a prescribed H ∞ performance of the sliding mode dynamics is guaranteed. Furthermore, the sliding mode controller is designed to assure that the state trajectories of the system will be driven onto the quasi-sliding surface and remain in there afterward. Finally, two numerical examples are given to illustrate the effectiveness of the proposed design algorithms.

Spouse Caregivers' Perceptions of Influence of Dementia on Marriage

2002 ◽  
Vol 14 (1) ◽  
pp. 47-58 ◽  
Author(s):  
Ulla Eloniemi-Sulkava ◽  
Irma-Leena Notkola ◽  
Kaija Hämäläinen ◽  
Terhi Rahkonen ◽  
Petteri Viramo ◽  
...  
Keyword(s):  
Behavioral Change ◽  
Intervention Study ◽  
Negative Impact ◽  
Behavioral Changes ◽  
Telephone Interviews ◽  
Before And After ◽  
Spouse Caregivers ◽  
Dementing Illness ◽  
Male Patients ◽  
Patients Experience

Objectives: To investigate what kind of changes spouse caregivers of demented patients experience after the onset of dementia (a) in the general atmosphere, happiness, and relations of marriage and (b) in the sexual side of marriage. Design: Semistructured telephone interviews of spouse caregivers of demented patients. Setting: Community-living demented patients and their spouse caregivers in eastern Finland. Participants: The spouse caregivers of 42 demented patients recruited from a previous intervention study. Measures: The questionnaire covered different areas of marriage from the time before and after the onset of dementia. Results: A statistically significant decline had occured in extent of happiness (p = .012), in equal relations (p = .001), and in patients' expressions of sexual needs (p < .001) when compared the time before and after dementia. Twenty-five (60%) of the caregivers reported that the demented patient had shown at least one negative sexual behavioral change during the course of dementia. Seven male patients (24%) had shown the behavioral symptom of constantly expressing need for making love. One in 10 caregivers had experienced positive sexual behavioral changes. In one third of the patients, the expressions of tenderness towards the caregiver had increased. Dementia did not affect significantly the general atmosphere of the marriage. Out of those still in home care, at 3 years from the onset of dementia, 19 couples (46%) continued to practice intercourse, at 5 years the number was 15 couples (41%), and at 7 years it had declined to 7 couples (28%). Conclusions: Dementing illness has a major negative impact on many dimensions of marriage. However, there are also positive changes and preserved aspects of marriage. Dementia seems to have a surprisingly little impact on whether the couple continues to have intercourse when compared with the general aging population.

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