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find Keyword "Markov model" 17 results
  • Study on method of laparoscopic training based on eye gaze tracking techniques

    In current domestic research on laparoscopic training, researchers usually consider instrument movement path in the hand-eye coordination relationship. However, they ignore the information contained in visual cues by which could guide and control instrument movements. Studies in other areas have shown that trainers can improve their perceptual-motor skills by gaze training. This paper was designed to examine the effectiveness of eye gaze tracking technology in laparoscopic training and to analyze gaze strategy of the subjects in different training methods. The Tobii X1 Light Eye Tracker was used to track the gaze position of subjects when they were performing the two-handed transferring task in box trainer, and to obtain parameters related to gaze strategy including the efficiency of task completion, as well as visual search, visual processing and observation transfer analysis based on Markov chain model. The results showed that the completion time during the last training in gaze training group was decreased by 101.5 s comparing to the first training. Compared with video training group, gaze strategy of gaze training group has a significant change, such as fixation and saccade duration rate was increased by 38%, fixation duration on target area was increased, and saccade amplitude increased by 0.58°, and the probability of the fixation point transferring to equipment decreased by 15%. The results demonstrated that eye gaze tracking technology can be used in laparoscopic training, and can improve the subjects’ skills and shorten the learning curve by learning gaze strategies of experts.

    Release date:2017-10-23 02:15 Export PDF Favorites Scan
  • Dupilumab injection in the treatment of moderate to severe atopic dermatitis in adults: a cost-effectiveness analysis

    ObjectiveTo evaluate the economics of duplizumab in combination with optimal supportive care versus optimal supportive care for moderate-to-severe atopic dermatitis in adults from the perspective of our health system. MethodsA Markov model embedded in a decision tree was constructed to compare the long-term cost-utility of dupilumab combined with optimal supportive care versus optimal supportive care, and a sensitivity analysis was performed on the results. ResultsThe results of the basic analysis showed that compared with the optimal supportive care, dupliyuzumab in combination with optimal supportive care resulted in 3.82 more QALYs, while its cost was 125 549.42 yuan more. The ICER was 32 854.83 yuan/QALY, which was less than one times China's per capita GDP in 2022, and was economical. Univariate sensitivity analysis showed that factors such as Dupilumab-16-week post - no response utility value, Dupilumab-52-week post response rate and Dupilumab-52-week adherence had a greater impact on the cost changes. The results of the probabilistic sensitivity analysis showed a stable model structure and good robustness. ConclusionIn adult patients with moderate-to-severe atopic dermatitis, dupliyuzumab in combination with an optimal supportive care regimen is more cost-effective compared to an optimal supportive care regimen.

    Release date:2024-05-13 09:34 Export PDF Favorites Scan
  • Affective Stress Rating Method Based on Improved Hidden Markov Model

    To solve the defect which is recognizing but not rating the stress, or rating but not considering the influence of the previous stress state to the current state of the existing affective stress evaluation method, this paper proposes an approach of affective stress rating model on electrocardiogram (ECG). An affective stress rating algorithm based on hidden Markov model (HMM) was established with the theory of affective computing. The individual's affective stress was rated using this affective rating model combining the investigation questionnaire. Features like complexity and approximate entropy of ECG were used in the model, and a matching process suggested that it improved the accuracy of affective stress rating. The result of the experiment illustrated that the model considering the environmental factors and the influence of previous stress state to the current state was an effective method in affective stress rating, and the accuracy of rating was improved by this affective stress rating method.

    Release date:2017-01-17 06:17 Export PDF Favorites Scan
  • Economic evaluation of human papillomavirus vaccine versus Chinese women aged 18 to 25 for treating cervical cancer

    Objective To evaluate the cost effectiveness of human papillomavirus vaccine (HPV) for treating cervical cancer. Methods We constructed a Markov model to evaluate the cost-effectiveness of HPV versus Chinese healthy women aged 18 to 25 for treating Cervical Cancer. We calculated the clinical benefits and cost-effectiveness and judged the results based on willing to pay. Sensitivity analysis was made for parameters like cost, discounting rate and vaccine efficacy. Results HPV vaccination was a cost-effective option under the local willing to pay value with the incremental cost utility ratio 43 489 per QALY gained. It proved that vaccination was an economic and effective solution. Conclusion Given the results of Markov model, the cost effectiveness of HPV vaccination of Chinese women aged 18 to 25 is positive. Considering the data sources and model hypothesis, this report has some limitations. Further studies are warranted.

    Release date:2017-01-18 07:50 Export PDF Favorites Scan
  • Hidden Markov models for human interactive behavior

    In order to meet the requirements in the cooperation and competition experiments for an individual patient in clinical application, two human interactive behavior key-press models based on hidden Markov model (HMM) were proposed. To validate the cooperative and competitive models, a verification experimental task was designed and the data were collected. The correlation of the score and subjects’ participation level has been used to analyze the reasonability verification. Behavior verification was conducted by comparing the statistical difference in response time for subjects between human-human and human-computer experiment. In order to verify the physiological validity of the models, we have utilized the coherence analysis to analyze the deep information of prefrontal brain area. Reasonability verification shows that the correlation coefficient for the training data and the testing data is 0.883 1 and 0.578 6 respectively based on cooperation model, and 0.813 1 and 0.617 8 respectively based on the competition model. The behavioral verification result shows that the cooperation and competition models have an accuracy of 71.43% respectively. The results of physiological validity show that the deep information of prefrontal brain area could been extracted based on the cooperation and competition models, and reveal the consistency of coherence between the double key-press cooperative and competitive experiments, respectively. Above all, the high consistency is obtained between the cooperatio/competition model and the double key-press experiment by the behavioral and physiological evaluation results. Consequently, the cooperation and competition models could be applied to clinical trials.

    Release date:2019-02-18 03:16 Export PDF Favorites Scan
  • Febuxostat versus allopurinol in chronic gout treatment: a pharmacoeconomic evaluation

    ObjectivesTo compare the efficacy and economy of febuxostat and allopurinol in the treatment of chronic gout, and to provide reference for clinical rational drug use.MethodsThe Markov model was established to conduct cost-effectiveness analysis for febuxostat and allopurinol serving as the front-line treated medicines. In view of the uncertainty of model parameters, single factor, probability sensitivity analysis and other methods were used to analyze the stability of the results.ResultsThe cost of the therapeutic schedule of allopurinol 300 mg was lower than febuxostat 40 mg, and it saved RMB 4 339.6 Yuan for each patients on average, while obtained 0.067 more QALY. Uncertainty analysis revealed that only those utility value which could not reach the standard influenced the final results in all included variable elements. When the aspiration payment value was zero, the percentage of therapeutic schedule for allopurinol 300 mg was 100. With the increase of aspiration payment value, the probability for febuxostat scheme becoming the superior one showed a very gradual growth. When the aspiration payment value reached 150 000, the probability still remained under 10%.ConclusionsAllopurinol is more economical than finasteride as the first choice in the treatment of chronic gout. Therefore, it is recommended that allopurinol should be used as the first-line drug for economical considerations.

    Release date:2018-06-20 02:05 Export PDF Favorites Scan
  • The survival analysis applied in calculation of markov model transition probability in pharmaceutical evaluation

    Markov model is one of the decision analysis models, which is widely used in pharmacoeconomic evaluation studies. In terms of dealing with changes of disease risks during different times, the transition probabilities among different Markov health states becomes hard to calculate. Nevertheless, survival analysis is an available resolution. In this paper, we introduced how to apply survival analysis in calculation of transition probability in time-dependent model based on cumulative probability with a case analysis on advanced gastric cancer Markov model, and provide more information for researchers to build models.

    Release date:2018-10-19 01:55 Export PDF Favorites Scan
  • A pace recognition method for exoskeleton wearers based on support vector machine-hidden Markov model

    In order to improve the motion fluency and coordination of lower extremity exoskeleton robots and wearers, a pace recognition method of exoskeleton wearer is proposed base on inertial sensors. Firstly, the triaxial acceleration and triaxial angular velocity signals at the thigh and calf were collected by inertial sensors. Then the signal segment of 0.5 seconds before the current time was extracted by the time window method. And the Fourier transform coefficients in the frequency domain signal were used as eigenvalues. Then the support vector machine (SVM) and hidden Markov model (HMM) were combined as a classification model, which was trained and tested for pace recognition. Finally, the pace change rule and the human-machine interaction force were combined in this model and the current pace was predicted by the model. The experimental results showed that the pace intention of the lower extremity exoskeleton wearer could be effectively identified by the method proposed in this article. And the recognition rate of the seven pace patterns could reach 92.14%. It provides a new way for the smooth control of the exoskeleton.

    Release date:2022-04-24 01:17 Export PDF Favorites Scan
  • Nab-paclitaxel plus gemcitabine vs. gemcitabine for metastatic pancreatic cancer in China: a health economic evaluation

    ObjectivesTo evaluate the economic efficacy of nab-paclitaxel (NAB-P) combined with gemcitabine (GEM) versus GEM alone in the treatment of metastatic pancreatic cancer in China.MethodsA Markov model simulating the costs and health outcomes was developed to estimate quality-adjusted life years (QALYs) and incremental cost-effectiveness ratio (ICER). The impact of parameter uncertainty on the model was assessed by deterministic one-way sensitivity analysis.ResultsNAB-P combined with GEM was shown superior efficacy compared to gemcitabine monotherapy, however with higher costs. The ICER between the two groups was 964 780.79¥/QALY.ConclusionsCompared with gemcitabine monotherapy, NAB-P combined with GEM is not cost-effective. The conclusion is confirmed by deterministic one-way sensitivity analysis.

    Release date:2019-09-10 02:02 Export PDF Favorites Scan
  • Cost-effectiveness analysis of thyroid disease screening in pregnant women in China

    Objective To compare the economic effectiveness of universal screening, high-risk population screening, and no screening strategies for thyroid disease prevention and control among pregnant women in China through cost-effectiveness analysis, providing evidence-based support for optimizing health policy decisions on prenatal thyroid disease screening. Methods Based on the characteristics of thyroid disorders during pregnancy, a combined decision tree and Markov model was developed to conduct a lifetime cost-effectiveness analysis across three strategies: no screening, high-risk population screening, and universal screening. Sensitivity analyses were performed on key parameters. Results Base-case analysis demonstrated that universal screening was the most cost-effective strategy when the World Health Organization (WHO)-recommended payment threshold of 1×gross domestic product (GDP) per capita was used, with an incremental cost-effectiveness ratio (ICER) of 20636.18 yuan per quality-adjusted life year (QALY) compared to no screening, followed by high-risk population screening (ICER=21071.71 yuan/QALY). The results of the sensitivity analysis showed a strong stability of the model. Conclusions Of the 3 screening programs for thyroid disease in pregnancy, universal screening is the most cost-effective when the WHO-recommended payment threshold of 1×GDP per capita is used.

    Release date:2025-04-27 01:50 Export PDF Favorites Scan
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