Status Transitions Research Articles

Optimization based method to develop representative driving cycle for real-world fuel consumption estimation

The lack of representative driving cycles is cited as one of main reasons for the increasing gap between vehicle test cycle and real-world fuel consumptions. Many past studies employed random and semi-random methods for developing driving cycles, by which the driving cycles aligned with real world driving characteristics may not be obtained. Besides, most of the existing methodologies were proposed for relative long trajectories, and cannot handle short trajectories “chopped” for road segments. Therefore, a new Simulated Annealing (SA) based method is proposed, resulting in a speed-acceleration pattern better aligned with real-world driving characteristics. The speed-acceleration status transitions are directly derived from the sample snippets rather than idealized trip trajectories based on SA optimization. In a case study in Fujian Province, China, the SA-based method could stably converge to observed values as the number of iterations increases and it greatly reduces the error by up to 23% over traditional methods. Finally, the accuracy of fuel consumption estimation is improved by imposing restriction on the starting and ending speeds of driving cycles. The method could improve fuel consumption estimation and also provide a better understanding on regional driving pattern, it can be used as a valuable tool for supporting energy and climate policies.

Potemkin village: the Barbados republic status transition advisory committee

The continuation of the symbolism of the presence of the British crown in the constitutional, political and cultural fabric of the Commonwealth has been a matter of public consideration and scholar...

Marital Status, Marital Transitions, and Sleep Quality in Mid to Late Life

This study aimed to understand how marital status and marital transitions were related to sleep quality in mid to late life and whether these findings differed by gender. Data from 2,872 participants 50-74 years old from the ORANJ BOWLSM, a longitudinal panel study in New Jersey, were used. Marital status and sleep quality were examined in two waves that were approximately 10 years apart. Individuals in a significant romantic relationship and women had worse sleep quality than those in other marital status groups and men. Compared to individuals who remained married, individuals who remained divorced or widowed or who became widowed had better sleep quality, whereas those who became divorced had worse sleep quality; individuals who transitioned into marriage had better sleep quality than those who remained divorced or widowed. Marital status and gender appear important for at least some indices of sleep quality, an important predictor of late-life health.

The Health Status Transition and Medical Expenditure Evaluation of Elderly Population in China.

(1) Background: Because of the rapid expansion of the aging population in China, their health status transition and future medical expenditure have received increasing attention. This paper analyzes the health transition of the elderly and how their health transition impacts medical expenditures. At the same time, feasible policy suggestions are provided to respond to the rising medical expenditure and the demand for social care. (2) Methods: The data were obtained from the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to 2015 and analyzed using the Markov model and the Two-Part model (TPM) to forecast the size of the elderly population and their medical expenditures for the period 2020–2060. (3) Results: The study indicates that: (1) for the elderly with a mild disability, the probability of their health improvement is high; in contrast, for the elderly with a moderate or severe disability, their health deterioration is almost certain; (2) the frequency of the diagnosis and treatments of the elderly is closely related to their health status and medical expenditure; alternatively, as the health status deteriorates, the intensity of the elderly individuals’ acceptance of their diagnosis and treatment increases, and so does the medical expense; (3) the population of the elderly with mild and moderate disability demonstrates an inverted “U”-shape, which reaches a peak around 2048, whereas the elderly with severe disability show linear growth, being the target group for health care; (4) with the population increase of the elderly who have severe disability, the medical expenditure increases significantly and poses a huge threat to medical service supply. Conclusions: It is necessary to provide classified and targeted health care according to the health status of the elderly. In addition, improving the level of medical insurance, establishing a mechanism for sharing medical expenditure, and adjusting the basic demographic structure are all important policy choices.

Tracking spatial dynamics of functional connectivity during a task

Functional connectivity (FC) measured from functional magnetic resonance imaging (fMRI) provides a powerful tool to explore brain organization. Studies of the temporal dynamics of brain organization have shown a large temporal variability of the functional connectome, which may be associated with mental status transitions and/or adaptive process. Most dynamic studies, e.g. functional connectome and functional network connectivity (FNC), have focused on the macroscopic FC changes, i.e. the changes of temporal coherence across various brain network sources, nodes and/or regions of interest, where it is assumed within the network or node that the FC is static. In this paper, we develop a novel method to examine the spatial dynamics of FC, without the assumption of its intra-network stationarity. We applied our approach to fMRI data during an auditory oddball task (AOD) from twenty-two subjects, in an attempt to capture/validate the approach by evaluating whether spatial connectivity varies with task condition. The results showed that connectivity networks exhibit spatial variability over time, in addition to participating in conventional temporal dynamics, i.e. cross-network variability or dynamic functional network connectivity (dFNC). Furthermore, we studied the relationship of spatial dynamic in FC to cognitive processes, by performing a cluster analysis to evaluate an individual's functional correspondence towards the ‘target’ (oddball) detection from AOD task, and extracting cognitive task correspondence states as well as their dynamic FC spatial maps segregated by such states. We found a clear trend in different task-guided states, particularly, a prominent reduction of task stimulus synchrony state along with strong anticorrelation between default mode network (DMN) and cognitive attentional networks. We also observed an increasing occurrence of the task desynchrony state which showed an absence of DMN anticorrelation. The results highlight the impact of a well-studied cognitive task on the observed spatial dynamic structure. We also showed that the FC spatial dynamic pattern from our method largely corresponds to macroscopic dFNC patterns, but with more details and specifications over space, meanwhile the connectivity within the source itself provides novel information and varies over time. Overall, we demonstrate clear evidence of the presence of the (usually ignored) spatial dynamics of connectivity, its links to the task and implications of cognition/mental status.

Five-year longitudinal study of frailty prevalence and course assessed using the Kihon Checklist among community-dwelling older adults in Japan

The aim of this study was to analyze the 5-year natural course of frailty status assessed with the Kihon Checklist (KCL) and the risk factors of transition towards frailty in community-dwelling older adults. We used the data from the postal KCL survey conducted by the municipal government between 2011 and 2016. The sample of the current study consisted of 551 older adults (265 men and 286 women) aged 65–70 years in 2011. The median KCL score increased from 2 (interquartile range 1–3) in 2011 to 3 (1–5) in 2016 (p < 0.001). Hence, the prevalence of frailty increased from 8.0 to 12.3% (p < 0.001). Regarding the 5-year transitions in frailty status, 68.3% of participants remained unchanged, while 21.4% transitioned towards a worse frailty status, and 10.3% towards an improved status. Of the 507 respondents who were robust or prefrail at the baseline, 44 experienced a transition towards frailty, indicating that the 5-year incidence of frailty was 8.7%. These 44 individuals had higher body mass indexes (BMI) and lower physical activity scores on the KCL than others (p < 0.05), the latter of which was an independent predictor of transition toward frailty in the multivariate analysis. This study was the first to evaluate the 5-year natural course of frailty status assessed using the KCL in community-dwelling elderly adults, in which the prevalence of frailty increased by 4.3%. To prevent transition towards frailty, maintaining optimal physical activity is recommended.

Sex work, gender transition, family rejection and depressive symptoms among transgender women in India

Background: Transgender women in India face unique stressors associated with minority experiences, such as experiences of gender transition and participation in sex work. However, the relationship between sex work, transition and mental health outcomes is understudied in this population. Aims: This article aims to examine the association between gender transition status, sex work, family rejection and depressive symptoms among transgender women in India. Methods: Data comes from a cross-sectional epidemiological study with transgender women from three states of India; Karnataka, Maharashtra and Tamil Nadu (N = 1366). Multivariate regressions were used to examine the association between sex work status and gender transition and how gender transition, and sex work are associated with depressive symptoms. Results: 70% of the sample reported being in sex work and over 82% endorsed taking some form of gender transition service. Those who reported being in sex work were significantly more likely to have undergone breast augmentation, hormonal therapy and gender affirming surgery. Those who reported ever being married were less likely to report gender affirming surgery and were more likely to report hormonal therapy. Additionally, being in sex work, undergoing transition, leaving home because of sexual orientation, and being married were significantly associated with depressive symptoms. Discussion: Community-led organizations and other service agencies must incorporate intersectional experiences and identities, including sex work and gender transition, in their programs to further social and health justice for transgender women in India. Policy and programmatic implications are discussed. Supplemental data for this article is available online at https://doi.org/10.1080/26895269.2021.1939220

Code status transitions in patients with high-risk acute myeloid leukemia (AML).

e19009 Background: Patients with high-risk AML often experience aggressive medical care at the end of life (EOL) such as hospitalization and intensive care unit (ICU) admission. Despite this, studies examining code status transitions in this population are lacking. Methods: We conducted a mixed methods study of 107 patients with high-risk AML enrolled in supportive care studies at Massachusetts General Hospital between 2014-2019. High-risk AML was defined as 1) new diagnosis &gt; 60 years or 2) relapsed/refractory AML. Two physicians used consensus-driven medical record review to characterize code status transitions. Code statuses were coded as ‘full’ (confirmed or presumed), ‘restricted’ (i.e., do not resuscitate), or ‘comfort measures only’ (CMO); confirmations of presumed status were not coded as transitions. Results: At diagnosis of high-risk AML, 91.9% of patients were ‘full code’ (48.5% presumed, 43.4% confirmed) and 8.1% had restrictions on life-sustaining therapies. Overall, 55.1% (59/107) of patients experienced a code status transition, with a median of two transitions (range 1-4). Median time from first to last transition was 11 days (range 1-306) and from last transition to death was 1 day (range 0-11). Most of these transitions (79.6%; 48/59) were transitions to CMO near EOL. We identified three processes leading to code status transitions (Table): 1) pre-emptive conversations prior to any clinical change (15.3%; 9/59); 2) anticipatory conversations at the time of acute clinical deterioration (15%; 9/59); and 3) futility conversations after acute clinical deterioration, focused on withdrawing life-sustaining therapy (64.4%; 38/59). Only 55.9% (33/59) of patients participated in their last code status transition and 22.0% (13/59) of these transitions occurred in the ICU or Emergency Room. Conclusions: Most patients with high-risk AML had code status transitions at EOL, often following clinical deterioration that limited their ability to engage in EOL discussions. Interventions to promote earlier and more specific code status conversations are needed to improve patients’ ability to voice their EOL preferences.[Table: see text]

Transitions in Smoking among Adults Newly Purchasing the JUUL System.

Objectives: In this study, we prospectively assessed changes in smoking a year after US adults' first-time purchase of a JUUL Starter Kit (JSK). Methods: Descriptive analyses assessed transitions in smoking status at 12 months among adult (age ≥21) JSK purchasers providing baseline and 12-month follow-up data (N = 27,164 [49.0% of baseline]), stratified by baseline smoking status. Baseline regular use of other ENDS was also considered. Results: Purchasers included baseline past 30-day smokers (65.2%), former smokers (12.0%), and never smokers (9.7%); over 90% were ever-smokers. One year later, the majority (58%) of those smoking at baseline reported no longer smoking. Former smokers or never smokers who were smoking at 12 months represented less than 2% of respondents. Former and current smokers who were regularly using other ENDS at baseline were less likely to report smoking at 12 months. Conclusions: Past 30-day smoking prevalence in a large longitudinal study of first-time JSK purchasers fell by more than half over 12 months. Analyzing the sample composition at purchase and transitions within subgroups defined by smoking status allows for a detailed understanding to help inform assessments of the population health impact of ENDS.

A Social Media Study on Mental Health Status Transitions Surrounding Psychiatric Hospitalizations.

For people diagnosed with a mental illness, psychiatric hospitalization is one step in a long journey, consisting of clinical recovery such as removal of symptoms, and social reintegration involving resuming social roles and responsibilities, overcoming stigma and self-maintenance of the condition. Both clinical recovery and social reintegration need to go hand-in-hand for the overall well-being of individuals. However, research exploring social media for mental health has considered narrower, disjoint conceptualizations of people with mental illness - either as a patient or as a support-seeker. In this paper, we combine medical records with social media data of 254 consented individuals who have experienced a psychiatric hospitalization to address this gap. Adopting a theory-driven, Gaussian Mixture modeling approach, we provide a taxonomy of six heterogeneous behavioral patterns characterizing peoples' mental health status transitions around hospitalizations. Then we present an empirically derived framework, based on feedback from clinical researchers, to understand peoples' trajectories around clinical recovery and social reintegration. Finally, to demonstrate the utility of this taxonomy and the empirical framework, we assess social media signals that are indicative of individuals' reintegration trajectories post-hospitalization. We discuss the implications of combining peoples' clinical and social experiences in mental health care and the opportunities this intersection presents to post-discharge support and technology-based interventions for mental health.

Depression or anxiety symptoms associated with occupational role transitions in Brazilian adults with a traumatic spinal cord injury: A multivariate analysis.

Psychological morbidity is commonly experienced by people with a spinal cord injury (SCI), but whether it is associated with occupational role transitions in is unknown. To analyze whether anxiety or depression symptoms are independently associated to increased likelihoods of role transitions in adults with SCI. Cross-sectional study; multivariate analysis using a heteroscedastic Dirichlet regression. Thirty persons with traumatic SCI. Role Checklist (e.g. role transitions: dependent variables) and Beck's Depression Inventory and State-Trait Anxiety Inventory (independent variables), adjusted for socio-demographic, functional, and injury-level confounders. Greater depression symptoms independently increased the likelihood of occupational role transitions, either for roles loss [adjusted Odds Ratio (AOR): 1.04; 95% confidence interval (CI):1.009-1.080] or roles gain [AOR: 1.07; 95% CI:1.02-1.13], as opposed to continued occupational roles. Higher anxiety as a trait, in turn, independently reduced the likelihood of occupational roles gain [AOR: 0.93; 95% CI: 0.869-0.992]. The "worker" role was the one lost more frequently (83%). Psychological morbidity is associated to occupational role transitions, as opposed to continued roles. Further research (e.g. with larger samples, longitudinal design, using structural equation modelling) should elucidate on the intricate relationships between mental health status and occupational role transitions in people experiencing SCI.

Pre-adolescence DNA methylation is associated with BMI status change from pre- to post-adolescence

BackgroundPrevious studies have shown that DNA methylation (DNAm) is associated with body mass index (BMI). However, it is unknown whether DNAm at pre-adolescence is associated with BMI status transition from pre- to post-adolescence. In the Isle of Wight (IoW) birth cohort, genome-wide DNA methylation in whole blood was measured using Illumina Infinium Human450 and EPIC BeadChip arrays in n = 325 subjects, and pre- to post-adolescence BMI transition was classified into four groups: (1) normal to normal, (2) normal to overweight or obese, (3) overweight or obese to normal, and (4) persistent overweight or obese. We used recursive random forest to screen genome-wide Cytosine-phosphate-Guanine (CpG) sites with DNAm potentially associated with BMI transition for each gender, and the association of BMI status transition with DNAm at an earlier age was assessed via logistic regressions. To evaluate gender specificity, interactions between DNAm and gender were included in the model. Findings in the IoW cohort were further tested in an independent cohort, the Avon Longitudinal Study of Parents and Children (ALSPAC).ResultsIn total, 174 candidate CpGs were selected including CpGs from screening and CpGs previously associated correctionally with BMI in children and adults. Of these 174 CpGs, pre-adolescent DNAm of 38 CpGs in the IoW cohort was associated with BMI status transition, including 30 CpGs showing gender-specific associations. Thirteen CpGs showed consistent associations between the IoW cohort and the ALSPAC cohort (11 of which were gender-specific).ConclusionPre-adolescence DNAm is associated with the change in BMI status from pre- to post-adolescence and such associations are likely to be gender-specific.

Guest Editorial: Data Analytics Streamlines Autonomous Driving

Artificial Intelligence (AI) incorporates the decision-making engine that is responsible for automating vehicle driving without human intervention. However, reliable and accurate decisions can only be concluded when a history of events has been accumulated by the AI engine for an extended set of operations over prolonged periods. The events are associated with status transitions of the vehicle while traveling between different geolocations. Vehicle sensors also generate sets of various information that reports platform status and the visuals of its surrounding domains including nearby objects. The automation system also acquires additional data from vehicle-to-vehicle communications and intelligent transportation systems. This diverse data helps to draw the Augmented Reality (AR) and Virtual Reality (VR) of surrounding domains that can also interact together to produce a new combined Mixed Reality (MR). Correlating all those realities with peripheral data sources leads to new 3D synergy namely eXtended Reality (XR). This aggregation of data is supported by key technology enablers such as cross-layer cyber-physical features and Bigdata storage. Training those families of labeled data improves the accuracy of machine learning predictions and safety of autonomous vehicles. This proves that acquiring more data with smart categorizing will enrich the autonomy of the transportation system.

Investigating the role of familial and peer-related factors on electronic nicotine delivery systems (ENDS) use among U.S. adolescents

IntroductionTobacco use is a public health concern, and adolescents are at an increased risk of starting and continuing to use tobacco relative to other age groups. Parent involvement and other social environmental factors may influence the development and persistence of tobacco use behaviors in adolescence. This study used the nationally representative Population Assessment of Tobacco and Health (PATH) study data set, and responses from 7025 adolescent participants were analyzed to illustrate the longitudinal relationship between social environment influences and use of adolescent electronic nicotine delivery systems (i.e., ENDS). MethodsSocial environmental factors were assessed at Wave 3 and then compared to electronic nicotine delivery systems (ENDS) status transitions (i.e., initiation, expansion, persistence) at follow-up. Survey-weighted multivariable logistic regression models were used to calculate adjusted odds ratios (AOR) and 95% confidence intervals (CI). ResultsInitiation and persistence of ENDS use were associated with tobacco availability in the house, perception of having no adverse parent reaction to discovering ENDS use and having a best friend who uses ENDS. Initiation of ENDS use was further associated with having biological relatives who have ever been diagnosed with a substance use disorder (SUD) and persistence of ENDS use was also positively associated with lack of in-house rules. Parents talking about ENDS use with adolescents had no association across all three outcomes. ConclusionsFindings suggest that parental and environmental factors alter the risk of initiation and persistence of ENDS and tobacco use in adolescents, and these should be considered when working with this at-risk population.

Sex differences in deterioration of sleep properties associated with aging: a 12-year longitudinal cohort study.

The sleep patterns of humans are greatly influenced by age and sex and have various effects on overall health as they change continuously during the lifespan. We investigated age-dependent changes in sleep properties and their relation to sex in middle-aged individuals. We analyzed data from 2,640 participants (mean age of 49.8 ± 6.8 years at baseline, 50.6% women) in the Korean Genome and Epidemiology Study, which assessed sleep habits using the Pittsburgh Sleep Quality Index and other clinical characteristics. We analyzed the sleep habit changes that occurred between baseline and a follow-up point (mean interval: 12.00 ± 0.16 years). Associations of age and sex with 9 sleep characteristics were evaluated. Age was associated with most of the sleep characteristics cross-sectionally and longitudinally (P < .05), except for the time in bed at baseline (P = .455) and change in sleep duration (P = .561). Compared with men, women had higher Pittsburgh Sleep Quality Index scores, shorter time in bed, shorter sleep duration, and longer latency at baseline (P ≤ .001). Longitudinal deterioration in Pittsburgh Sleep Quality Index score, habitual sleep efficiency, duration, and latency was more prominent in women (P < .001). The sex differences in these longitudinal sleep changes were mainly noticeable before age 60 years (P < .05). Worsening of Pittsburgh Sleep Quality Index scores, habitual sleep efficiency, and latency was most evident in perimenopausal women. Men presented with greater advancement of chronotype (P = .006), with the peak sex-related difference occurring when they were in their late 40s (P = .048). Aging is associated with substantial deterioration in sleep quantity and quality as well as chronotype advancement, with the degree and timing of these changes differing by sex.

So called athletic identity, incompatible with reality: Static identity structure, status transitions and health behaviour dynamics in student athletes

The aim of the present study is to examine the athletic identity, status transitions and health-related behavioral dynamics of student athletes. Descriptive survey model was used and 398 individuals participated in the present study. Data was collected by Athletic Identity Measurement Scale (AIMS), information form, ranking and closed-ended qualitative questions. According to findings, it was found that the students' downright transitions increased in processes. On the contrary, ANOVA analyses show no differences in athletic identity scores according to grade levels (p&gt;.05). An increase was seen in maladaptive health behaviors (p&lt;.05). Additionally, maladaptive health behaviors increase after sport termination and beginning of university. It was concluded as a result of the study that individuals' acceptance of athletic identity becomes continuous in spite of the changes in their sport participation status; however, health behaviors are not compatible with the continuity of athletic identity.

Predictors of Mild Cognitive Impairment Stability, Progression, or Reversion in the Lothian Birth Cohort 1936.

Background:Mild cognitive impairment (MCI) describes a borderland between healthy cognition and dementia. Progression to and reversion from MCI is relatively common but more research is required to understand the factors affecting this fluidity and improve clinical care interventions.Objective:We explore these transitions in MCI status and their predictive factors over a six-year period in a highly-phenotyped longitudinal study, the Lothian Birth Cohort 1936.Methods:MCI status was derived in the LBC1936 at ages 76 (n = 567) and 82 years (n = 341) using NIA-AA diagnostic guidelines. Progressions and reversions between healthy cognition and MCI over the follow-up period were assessed. Multinomial logistic regression assessed the effect of various predictors on the likelihood of progressing, reverting, or maintaining cognitive status.Results:Of the 292 participants who completed both time points, 41 (14%) participants had MCI at T1 and 56 (19%) at T2. Over the follow-up period, 74%remained cognitively healthy, 12%transitioned to MCI, 7%reverted to healthy cognition, and 7%maintained their baseline MCI status. Findings indicated that membership of these transition groups was affected by age, cardiovascular disease, and number of depressive symptoms.Conclusion:Findings that higher baseline depressive symptoms increase the likelihood of reverting from MCI to healthy cognition indicate that there may be an important role for the treatment of depression for those with MCI. However, further research is required to identify prevention strategies for those at high risk of MCI and inform effective interventions that increase the likelihood of reversion to, and maintenance of healthy cognition.

Is Democracy Good for Corporate Investment?

Using corporate data in 19 countries that experienced democracy status transitions between 1983 and 2017, we find that firm investment decreases by over 30% following democratization. This negative democracy-investment relationship is driven by higher employee welfare and regulatory costs and is stronger for politically connected firms, financially unconstrained firms and in less corrupted countries. The firm investment drop is also due primarily to the reduced investment inefficiency that accompanies higher post-democratization firm profitability, valuation, and stock return. The initial drop has a duration of only two years, and firm investment eventually increases in the fifth year after democratization. Several robustness tests and IV regressions further confirm our main results.

Association of Dietary Intake with the Transitions of Frailty among Japanese Community-Dwelling Older Adults

BackgroundFrailty is a dynamic process, with frequent transitions between frailty, prefrailty, and robust statuses over time. The effect of dietary intake on frailty transitions is unknown.ObjectiveTo examine the association between dietary intake and frailty transitions.DesignSurvey-based retrospective analysis of the National Institute for Longevity Sciences-Longitudinal Study of Aging data.SettingAreas neighboring the National Center for Geriatrics and Gerontology in Aichi Prefecture, Japan.ParticipantsWe included 469 prefrail community dwellers aged 60–87 years who participated both in the baseline (2008–2010) and 2-year follow-up (2010–2012) surveys of the National Institute for Longevity Sciences-Longitudinal Study of Aging.MeasurementsTransitions of frailty were categorized by changes in status from baseline to follow-up: “deterioration (prefrail to frail),” “persistence (persistent prefrail),” and “reversal (prefrail to robust).” Estimated dietary (nutrients and food) intakes assessed by 3-day dietary records in each frailty transition were analyzed with a multivariate-adjusted general linear model after adjusting for sex, age, education, family income, smoking, and chronic disease.ResultsAt the 2-year follow-up, 28%, 7%, and 65% of participants had robust, frail, and pre-frail status, respectively. Among 13 food groups, only milk and dairy product intake was positively associated with frailty reversal even after adjusting for all frailty criteria at baseline. Despite insignificant differences in the estimated mean intakes, the baseline intake of saturated fatty acids, potassium, and vitamin B1 tended to be the highest in the reversal group. The estimated mean (standard error) for milk and dairy product intake (g/day) was 79.1 (28.6), 129.3 (19.9), and 161.7 (21.7) for the deterioration, persistence, and reversal groups, respectively (P=0.0036, P-trend=0.0019).ConclusionsDaily consumption of dairy products may contribute to frailty reversal and frailty prevention among older community dwellers who consume small amounts of dairy products. Other food groups showed no association with frailty status transitions.

Detection of Covert Timing Channel Based on Time Series Symbolization

Covert Timing Channels(CTCs) is a technique to leak information. CTCs only modify inter-arrival time sequence(IATs) between packets, consequently, traditional network security mechanisms, such as firewalls and proxies, can not effectively detect CTCs. If CTCs are maliciously utilized by criminals, will pose a great threat to network security. Classic CTCs detection methods, such as KS-test, Entropy-test, etc, not only have less universality and robustness, but also require more sampled IATs to detect CTCs, therefore, how to improve performance of detection methods against CTCs, has became a popular research in recent years. In this paper, a new CTCs detection method based on time series symbolization is proposed. It firstly converts the sampled IATs to symbolic time series, and regards each discrete value as a status. Then counts the times of transition for each status to status, and calculates the status transition probability matrix(STPM). Finally, it differentiates the label(overt or covert) of sampled IATs, by calculating similarity score. Experimental results about detection accuracy show that, in an ideal network environment, compared with classic methods, our method has better performance, with average accuracy of about 96%. Besides, our method has better performance as well, with the existence of network interference.