The serpentine convergent-divergent nozzle represents an optimal configuration for nextgeneration fighter aircraft characterized by low detectability and high thrust-to-weight ratio.In contrast to the serpentine conve...The serpentine convergent-divergent nozzle represents an optimal configuration for nextgeneration fighter aircraft characterized by low detectability and high thrust-to-weight ratio.In contrast to the serpentine convergent nozzle,such configuration offers increased design flexibility with additional parameters,leading to heightened interactions among these parameters.As such,it is crucial to reveal the influence of design parameters on the aerodynamic performance of the serpentine convergent-divergent nozzle and the multifactor interaction,as well as its mechanism.Therefore,the influence,interaction and sensitivity of parameters on the aerodynamic performance of the nozzle were numerically investigated using the orthogonal test method.Additionally,the influence mechanism of the convergence angle,throat aspect ratio,and axial length to inlet diameter on the flow characteristics of the nozzle was investigated in detail.The results show that the convergence angle is identified as the main factor affecting the aerodynamic parameters of the nozzle.As the convergence angle increases,the thrust coefficient,total pressure recovery coefficient and discharge coefficient gradually decrease.The interaction between throat aspect ratio and other parameters is obvious.Different design parameters affect the local loss and the friction loss by affecting the curvature and wetted perimeter area,resulting in different aerodynamic characteristics of serpentine convergent-divergent nozzle.展开更多
BACKGROUND Gallbladder cancer(GBC)is the most common malignant tumor of the biliary system,and is often undetected until advanced stages,making curative surgery unfeasible for many patients.Curative surgery remains th...BACKGROUND Gallbladder cancer(GBC)is the most common malignant tumor of the biliary system,and is often undetected until advanced stages,making curative surgery unfeasible for many patients.Curative surgery remains the only option for long-term survival.Accurate postsurgical prognosis is crucial for effective treatment planning.tumor-node-metastasis staging,which focuses on tumor infiltration,lymph node metastasis,and distant metastasis,limits the accuracy of prognosis.Nomograms offer a more comprehensive and personalized approach by visually analyzing a broader range of prognostic factors,enhancing the precision of treatment planning for patients with GBC.AIM A retrospective study analyzed the clinical and pathological data of 93 patients who underwent radical surgery for GBC at Peking University People's Hospital from January 2015 to December 2020.Kaplan-Meier analysis was used to calculate the 1-,2-and 3-year survival rates.The log-rank test was used to evaluate factors impacting prognosis,with survival curves plotted for significant variables.Single-factor analysis revealed statistically significant differences,and multivariate Cox regression identified independent prognostic factors.A nomogram was developed and validated with receiver operating characteristic curves and calibration curves.Among 93 patients who underwent radical surgery for GBC,30 patients survived,accounting for 32.26%of the sample,with a median survival time of 38 months.The 1-year,2-year,and 3-year survival rates were 83.87%,68.82%,and 53.57%,respectively.Univariate analysis revealed that carbohydrate antigen 19-9 expre-ssion,T stage,lymph node metastasis,histological differentiation,surgical margins,and invasion of the liver,ex-trahepatic bile duct,nerves,and vessels(P≤0.001)significantly impacted patient prognosis after curative surgery.Multivariate Cox regression identified lymph node metastasis(P=0.03),histological differentiation(P<0.05),nerve invasion(P=0.036),and extrahepatic bile duct invasion(P=0.014)as independent risk factors.A nomogram model with a concordance index of 0.838 was developed.Internal validation confirmed the model's consistency in predicting the 1-year,2-year,and 3-year survival rates.CONCLUSION Lymph node metastasis,tumor differentiation,extrahepatic bile duct invasion,and perineural invasion are independent risk factors.A nomogram based on these factors can be used to personalize and improve treatment strategies.展开更多
Objective This study aimed to explore the association of single nucleotide polymorphisms(SNP)in the matrix metalloproteinase 2(MMP-2)signaling pathway and the risk of vascular senescence(VS).Methods In this cross-sect...Objective This study aimed to explore the association of single nucleotide polymorphisms(SNP)in the matrix metalloproteinase 2(MMP-2)signaling pathway and the risk of vascular senescence(VS).Methods In this cross-sectional study,between May and November 2022,peripheral venous blood of151 VS patients(case group)and 233 volunteers(control group)were collected.Fourteen SNPs were identified in five genes encoding the components of the MMP-2 signaling pathway,assessed through carotid-femoral pulse wave velocity(cf PWV),and analyzed using multivariate logistic regression.The multigene influence on the risk of VS was assessed using multifactor dimensionality reduction(MDR)and generalized multifactor dimensionality regression(GMDR)modeling.Results Within the multivariate logistic regression models,four SNPs were screened to have significant associations with VS:chemokine(C-C motif)ligand 2(CCL2)rs4586,MMP2 rs14070,MMP2rs7201,and MMP2 rs1053605.Carriers of the T/C genotype of MMP2 rs14070 had a 2.17-fold increased risk of developing VS compared with those of the C/C genotype,and those of the T/T genotype had a19.375-fold increased risk.CCL2 rs4586 and MMP-2 rs14070 exhibited the most significant interactions.Conclusion CCL2 rs4586,MMP-2 rs14070,MMP-2 rs7201,and MMP-2 rs1053605 polymorphisms were significantly associated with the risk of VS.展开更多
Mastitis is a complex, multifactorial disease. Pathogens, cows and farmers （via management） all play a role. It is costly and annoying for the farmer and threatens the image of the entire dairy industry. Prevention ...Mastitis is a complex, multifactorial disease. Pathogens, cows and farmers （via management） all play a role. It is costly and annoying for the farmer and threatens the image of the entire dairy industry. Prevention and control of mastitis is based on multiple principles that have been known for a long time. To implement them successfully, they should be put forward by a motivated and motivating advisor that transfers the existing knowledge to the farmer. When the changes are data-driven, applied by an encouraged farmer through a farm-specific implementation, prevention and control of mastitis will be successful and result in happy cows, happy farmers, happy advisors, happy consumers, and a happy industry. Nationwide projects focussing on communication and transfer of existing knowledge in prevention and control are very helpful in reaching high numbers of farmers and advisors and harmonizing the message brought by different parties. This paper gives an overview of multifactorial approach of mastitis management and prevention with a focus on milking, bedding and data-analysis.展开更多
Functional zoning is an important mechanism for achieving national park planning and management objective.Better functional zoning is of great significance to the protection of ecosystem legitimacy and integrity,the a...Functional zoning is an important mechanism for achieving national park planning and management objective.Better functional zoning is of great significance to the protection of ecosystem legitimacy and integrity,the appropriate utilization of resources,community integration,and feasible management.In the present study,the proposed Qinghai Lake National Park is the research object.Based on the critical goal of ecological protection,the importance of ecosystem service functions and the ecological sensitivities were evaluated.The results showed that the ecosystem service functions and the ecological sensitivity of the whole region are high.Among them,lake,river and wetland as the most strictly protected ecosystems account for the highest proportion.Then this study divided the proposed Qinghai Lake National Park into five functional areas through grid calculations,spatial analysis and multifactor trade-off.The results indicated that the goal of functional zoning for national park is to maximize the overall utility of park protection value and its comprehensive functions based on its spatial units with different functions,management and control requirements.The zoning scheme addresses the lack of sustainable development in Qinghai Lake National Park due to ecological environmental changes and single-resource zoning with resource protection as the primary goal.This study can serve as a reference for spatial functional zoning methods of national land parks,nature reserves and other natural protected areas.展开更多
The soybean aphid, Aphis glycines Matsumura(Hemiptera: Aphididae), is one of the greatest threats to soybean production, and both trend analysis and periodic analysis of its population dynamics are important for integ...The soybean aphid, Aphis glycines Matsumura(Hemiptera: Aphididae), is one of the greatest threats to soybean production, and both trend analysis and periodic analysis of its population dynamics are important for integrated pest management(IPM). Based on systematically investigating soybean aphid populations in the field from 2018 to 2020, this study adopted the inverse logistic model for the first time, and combined it with the classical logistic model to describe the changes in seasonal population abundance from colonization to extinction in the field. Then, the increasing and decreasing phases of the population fluctuation were divided by calculating the inflection points of the models, which exhibited distinct seasonal trends of the soybean aphid populations in each year. In addition, multifactor logistic models were then established for the first time, in which the abundance of soybean aphids in the field changed with time and relevant environmental conditions. This model enabled the prediction of instantaneous aphid abundance at a given time based on relevant meteorological data. Taken as a whole, the successful approaches implemented in this study could be used to build a theoretical framework for practical IPM strategies for controlling soybean aphids.展开更多
Based on Wiener process model, a new approach for reliability evaluation of cross-linked polyethylene(XLPE) is proposed to improve the lifetime evaluation reliability of XLPE under multi-stressing conditions and study...Based on Wiener process model, a new approach for reliability evaluation of cross-linked polyethylene(XLPE) is proposed to improve the lifetime evaluation reliability of XLPE under multi-stressing conditions and study the failure probability distribution. In this paper, two accelerated aging tests are carried out under combined thermal and vibration conditions. The volume resistance degradation data of XLPE samples are tested with a24 h interval under the accelerated stressing conditions at(130℃, 12 m/s^2) and(150℃, 8.5 m/s^2), respectively.Nonlinear degradation data obtained from the experiment are transformed to linear intermediate-variable values using time scaling function, and then linearized degradation data are calculated and evaluated on the basis of linear Wiener process model. Considering traditional Arrhenius equation and inverse power criterion, parameters of the linear Wiener model are estimated according to the maximum likelihood function. The relationship curves on probability density and reliability are given, and the lifetime distribution of XLPE under different stressing conditions is also obtained for evaluating the reliability of XLPE insulation. Finally, the life expectancy of XLPE is 17.9 a under an allowance temperature of 90℃ and an actual vibration acceleration of 0.5 m/s^2. The approach and results in this paper may be used for reliability assessment of high-voltage multiple samples or apparatuses.展开更多
Objective The effects of interactions between genetic and environmental factors on the noise-induced hearing loss(NIHL)are still unclear.This study aimed to assess interactions among gene polymorphisms,noise metrics,a...Objective The effects of interactions between genetic and environmental factors on the noise-induced hearing loss(NIHL)are still unclear.This study aimed to assess interactions among gene polymorphisms,noise metrics,and lifestyles on the risk of NIHL.Methods A case-control study was conducted using 307 patients with NIHL and 307 matched healthy individuals from five manufacturing industries.General demographic data,lifestyle details,and noise exposure levels were recorded.The Kompetitive allele-specific polymerase chain reaction(KASP)was used to analyze the genotypes of 18 SNPs.Results GMDR model demonstrated a relevant interaction between NRN1 rs3805789 and CAT rs7943316(P=0.0107).Subjects with T allele of rs3805789 or T allele of rs7943316 had higher risks of NIHL than those with the SNP pair of rs3805789-CC and rs7943316-AA(P<0.05).There was an interaction among rs3805789,rs7943316,and kurtosis(P=0.0010).Subjects exposed to complex noise and carrying both rs3805789-CT and rs7943316-TT or rs3805789-CT/TT and rs7943316-AA had higher risks of NIHL than those exposed to steady noise and carrying both rs3805789-CC and rs7943316-AA(P<0.05).The best six-locus model involving NRN1 rs3805789,CAT rs7943316,smoking,video volume,physical exercise,and working pressure for the risk of NIHL was found to be the interaction(P=0.0010).An interaction was also found among smoking,video volume,physical exercise,working pressure,and kurtosis(P=0.0107).Conclusion Concurrence of NRN1 and CAT constitutes a genetic risk factor for NIHL.Complex noise exposure significantly increases the risk of NIHL in subjects with a high genetic risk score.Interactions between genes and lifestyles as well as noise metrics and lifestyles affect the risk of NIHL.展开更多
Nighttime sap flow(Q_(n))is an important physiological activity under which trees manage drought stress.An in-depth understanding of the characteristics of Q_(n)and its response to environmental and canopy conditions ...Nighttime sap flow(Q_(n))is an important physiological activity under which trees manage drought stress.An in-depth understanding of the characteristics of Q_(n)and its response to environmental and canopy conditions are of significance for arid area forest and water management.This study measured daily sap flow(Q_(s))of a Larix principis-rupprechtii plantation in the Liupan Mountains,northwest China during the 2017-2019 growing seasons,and separated Q_(s)into daytime sap flow(Qd)and Q_(n).Meteorological conditions(reference evapotranspiration,ETref),canopy structure(leaf area index,LAI),and soil moisture(relative soil water content,RSWC)were considered as the main biophysical factors affecting Q_(n).The structural equation model and upper boundary line method determined the effects of compound and single factors on Q_(n)The daily mean Q_(n)values during the growing seasons in 2017,2018,and 2019 were 0.024,0.026,and 0.030 mm d-1,accounting for 6.2,11.2,and 10.1%of Q_(s),respectively.Q_(n)at different canopy development phases(leaf expanding,LG;leaf expanded,LD;and defoliation,DF)over three years was LD>LG>DF.Q_(n)increased with increasing ETref,whereas the ratio of Q_(n)to Q_(s)decreased.Q_(n)did not show regular variation in the three-year growing seasons under different soil moisture conditions.ETrefand LAI mainly controlled Q_(n)by affecting Qd,whereas RSWC had no significant effect on Q_(n).Q_(n)had a positive and linear relationship with LAI and a quadratic relationship with ETref.Both explained 40%of variation in Q_(n)Meteorological and canopy conditions are important factors affecting Q_(n)on the semi-humid study site.The application of the Q_(n)model coupled with the impact of ETrefand LAI furthers understanding of the impacts of climate and forest structure change on Q_(n).展开更多
Objective: To understand the status quo of PICC Catheter-associated Skin Impairment (CASI) in some hospitals at all levels in Jingzhou city, and to explore the risk factors for PICC Catheter-associated Skin Impairment...Objective: To understand the status quo of PICC Catheter-associated Skin Impairment (CASI) in some hospitals at all levels in Jingzhou city, and to explore the risk factors for PICC Catheter-associated Skin Impairment. Methods: From June 2019 to July 2020, a self-made questionnaire for CASI status was used to facilitate the extraction of CASI patients in PICC in some hospitals at all levels in Jingzhou city. Local skin lesions were collected and classified during PICC maintenance, and the damage types, occurrence frequency and related influencing factors of CASI were counted to identify independent risk factors. Results: In this study, there were 173 cases of CASI in PICC’s patients including local infection 56.1% (97/173), exudation at the puncture site 16.8% (29/173), irritant dermatitis 21.4% (37/173), allergic dermatitis 4.6% (8/173), and tension injury 1.2% (2/173). After univariate analysis, there were statistically significant differences between CASI occurrence type and duration of catheter wear, age, underlying disease, skin moisture and hyperhidrosis, PICC maintenance as required, hospital grade maintenance and intermittent chemotherapy (P < 0.05). Then, disordered multiple Logistic regression analysis was performed, and exudation at the puncture site was used as the reference group. The results showed that patients with PICC were more likely to have CASI if they were aged, long catheter time, had diabetes, had moist and sweaty skin, and were in the intermittent stage of chemotherapy. Conclusion: The incidence of CASI is high in patients aged 70 - 79 years, and local infection is the most common. PICC’s patients with diabetes are at high risk of CASI. PICC’s patients with excessive sweating are more likely to have CASI. The intermittent stage of chemotherapy is the excessive CASI;time with tube affects CASI occurrence.展开更多
Process integration method is used to establish a composite model to perform computations of hybrid models for water quality assessment of Haihe River, and a resolution is presented to clear the long-term obscurity ab...Process integration method is used to establish a composite model to perform computations of hybrid models for water quality assessment of Haihe River, and a resolution is presented to clear the long-term obscurity about the differences between single-factor assessment(SFA) and multifactor assessment(MFA) of water quality in this paper. Symbolic models were introduced to describe the types and orders of computations involved in SFA and such MFAs as Nemerow comprehensive index(NCI) and fuzzy comprehensive assessment(FCA). Facilitated by paired t-tests, the composite model of absolute distance(AD) was established to test the differences between SFA and MFAs on four water quality indicators(WQI). Matlab(R14) programs for these models were developed to perform integrative computations on 3 217 batches of water data obtained from seven monitoring sites of Haihe River from 2008 to 2017. Paired t-tests show that results of our SFA model(SFA-4) are not significantly different(p=0.926) from that of SFA based on all WQI, however, extremely significantly different from results of NCI(p=0) and FCA(p=0). SFA-4 is proved by AD model to be farther away from FCA(AD-S→F=1.075) than from NCI(AD-S→N=0.634). More than proving the deduction of SFA≥NCI≥FCA in most cases(p=0.885), the results from AD show that MFAs approach SFA when surface water becomes good(SFA=1) or worst(SFA=6), whereas depart to the farthest distance from SFA when surface water becomes worse(SFA=3). To sum up, the integrative computations involved in AD model on the water data are effective and efficient(improved by 44.2%). Furthermore, AD model shows the differences between SFA and MFAs clearly.展开更多
The COVID-19 outbreak and its medical distancing phenomenon have effectively turned the global healthcare challenge into an opportunity for Telecare Medical Information Systems.Such systems employ the latest mobile an...The COVID-19 outbreak and its medical distancing phenomenon have effectively turned the global healthcare challenge into an opportunity for Telecare Medical Information Systems.Such systems employ the latest mobile and digital technologies and provide several advantages like minimal physical contact between patient and healthcare provider,easy mobility,easy access,consistent patient engagement,and cost-effectiveness.Any leakage or unauthorized access to users’medical data can have serious consequences for any medical information system.The majority of such systems thus rely on biometrics for authenticated access but biometric systems are also prone to a variety of attacks like spoong,replay,Masquerade,and stealing of stored templates.In this article,we propose a new cancelable biometric approach which has tentatively been named as“Expression Hash”for Telecare Medical Information Systems.The idea is to hash the expression templates with a set of pseudo-random keys which would provide a unique code(expression hash).This code can then be serving as a template for verication.Different expressions would result in different sets of expression hash codes,which could be used in different applications and for different roles of each individual.The templates are stored on the server-side and the processing is also performed on the server-side.The proposed technique is a multi-factor authentication system and provides advantages like enhanced privacy and security without the need for multiple biometric devices.In the case of compromise,the existing code can be revoked and can be directly replaced by a new set of expression hash code.The well-known JAFFE(The Japanese Female Facial Expression)dataset has been for empirical testing and the results advocate for the efcacy of the proposed approach.展开更多
To realize the automatic detection of solar radio burst(SRB)intensity,detection based on a modified multifactor support vector machine(SVM)algorithm is proposed.First,the influence of SRB on global navigation satellit...To realize the automatic detection of solar radio burst(SRB)intensity,detection based on a modified multifactor support vector machine(SVM)algorithm is proposed.First,the influence of SRB on global navigation satellite system(GNSS)signals is analyzed.Feature vectors,which can reflect the SRB intensity of stations,are also extracted.SRB intensity is classified according to the solar radio flux,and different class labels correspond to different SRB intensity types.The training samples are composed of feature vectors and their corresponding class labels.Second,training samples are input into SVM classifiers to one-against-one training to obtain the optimal classification models.Finally,the optimal classification model is synthesized into a modified multifactor SVM classifier,which is used to automatically detect the SRB intensity of new data.Experimental results indicate that for historical SRB events,the average accuracy of SRB intensity detection is greater than 90%when the solar incident angle is higher than 20°.Compared with other methods,the proposed method considers many factors with higher accuracy and does not rely on radio telescopes,thereby saving cost.展开更多
Chronic heart failure (CHF) is a clinical syndrome as a common pathway at the end stage of cardiac diseases of different etiologies, and it is currently the only cardiovascular disease with an increasing prevalenc... Chronic heart failure (CHF) is a clinical syndrome as a common pathway at the end stage of cardiac diseases of different etiologies, and it is currently the only cardiovascular disease with an increasing prevalence in the developed countries. In the United States, the prevalence of CHF at age 50 years is 1.0%, whereas it reaches 7.5% at age 80years. In the United Kingdom, the prevalence of CHF is5.0% at age 60-70 years, and 10-20% at age 80 years. The situation is similar in Italy and Portugal. Despite being a developing country in Asia, China has experienced rapid progress in acquiring medical knowledge and advancing techniques in recent years. Due to the markedly declined mortality of acute myocardial infarction (AMI) as well as the aging of Chinese population, about four million Chinese have CHF with a prevalence of 0.9%, most of whom are 60 years of age and older.……展开更多
Objective:To analyze the syndrome characteristics in patients with chronic persistent asthma.Methods:365 patients(121 males,244 females,60.829.1 years old)with chronic persistent asthma were enrolled in this cross-sec...Objective:To analyze the syndrome characteristics in patients with chronic persistent asthma.Methods:365 patients(121 males,244 females,60.829.1 years old)with chronic persistent asthma were enrolled in this cross-sectional study.The information of syndrome,symptoms,signs,tongue coating and pulse were collected from all patients.The syndrome characteristics of chronic persistent asthma were examined through the multifactor dimensionality reduction(MDR)analysis and the results were verified by the Chi-square test.Results:The results of the MDR analysis and the Chi-square test showed the following positive correlation of the interaction among:the deficiency syndrome of the lung and spleen and deep pulse,disinclination to talk due to lack of qi,fatigue,lassitude and thick tongue coating;the deficiency syndrome of the lung and kidney and dizziness and disinclination to talk due to lack of qi,fatigue,lassitude and pallid complexion;the syndrome of phlegm-heat obstructing the lung and rapid pulse,abdominal distension,disinclination to talk due to lack of qi,frequent urination and lassitude;the syndrome of phlegm-dampness obstructing the lung and disinclination to talk due to lack of qi,greasy coating,fatigue and lassitude.(P<.05 for all).Conclusion:The syndrome of chronic persistent asthma is characterized by fatigue and lassitude due to dysfunction of the lung,spleen and kidney.展开更多
This study investigates the effects of changes in local macroeconomic risk factors on returns on the banking,chemicals,insurance,telecommunication,and utilities industries in the U.S.market.Using a multifactor pricing...This study investigates the effects of changes in local macroeconomic risk factors on returns on the banking,chemicals,insurance,telecommunication,and utilities industries in the U.S.market.Using a multifactor pricing model and data from 1998:01 to 2017:12,empirical results show that the banking,chemical,and telecommunication industries show more differences in their stock reactions to local macroeconomic risk factors.The insurance and telecommunication industries do not react significantly to risk factors.However,all the industries show strong reactions to local market portfolio.展开更多
We develop various statistical methods important for multidimensional genetic data analysis. Theorems justifying application of these methods are established. We concentrate on the multifactor dimensionality reduction...We develop various statistical methods important for multidimensional genetic data analysis. Theorems justifying application of these methods are established. We concentrate on the multifactor dimensionality reduction, logic regression, random forests, stochastic gradient boosting along with their new modifications. We use complementary approaches to study the risk of complex diseases such as cardiovascular ones. The roles of certain combinations of single nucleotide polymorphisms and non-genetic risk factors are examined. To perform the data analysis concerning the coronary heart disease and myocardial infarction the Lomonosov Moscow State University supercomputer “Chebyshev” was employed.展开更多
Xu deep volcanic gas reservoir is typical of complex lithology, severe inhomogeneity, big difficulty to extract. Pressure sensitivity always exists in gas reservoirs. Prorating production is too high or low, causing p...Xu deep volcanic gas reservoir is typical of complex lithology, severe inhomogeneity, big difficulty to extract. Pressure sensitivity always exists in gas reservoirs. Prorating production is too high or low, causing problems, as for the energy loss, reservoir damage, bottom effusion, thus lowing the gas productivity and affecting development benefit. So it have to research on a new reasonably production proration method considering multi influential factors. It is a reasonably production proration method considering multi influential factors in Xu gas reservoir, with guidelines such as capacity use, pressure draw down, gas recovery rate, water out and throughout water data is reasonably, so we can long term use it to guide gas field exploitation.展开更多
Cloud computing(CC)is an advanced technology that provides access to predictive resources and data sharing.The cloud environment represents the right type regarding cloud usage model ownership,size,and rights to acces...Cloud computing(CC)is an advanced technology that provides access to predictive resources and data sharing.The cloud environment represents the right type regarding cloud usage model ownership,size,and rights to access.It introduces the scope and nature of cloud computing.In recent times,all processes are fed into the system for which consumer data and cache size are required.One of the most security issues in the cloud environment is Distributed Denial of Ser-vice(DDoS)attacks,responsible for cloud server overloading.This proposed sys-tem ID3(Iterative Dichotomiser 3)Maximum Multifactor Dimensionality Posteriori Method(ID3-MMDP)is used to overcome the drawback and a rela-tively simple way to execute and for the detection of(DDoS)attack.First,the pro-posed ID3-MMDP method calls for the resources of the cloud platform and then implements the attack detection technology based on information entropy to detect DDoS attacks.Since because the entropy value can show the discrete or aggregated characteristics of the current data set,it can be used for the detection of abnormal dataflow,User-uploaded data,ID3-MMDP system checks and read risk measurement and processing,bug ratingfile size changes,orfile name changes and changes in the format design of the data size entropy value.Unique properties can be used whenever the program approaches any data error to detect abnormal data services.Finally,the experiment also verifies the DDoS attack detection capability algorithm.展开更多
Non-parametric methods are treasured in data analysis,particularly in finance.ST-metric is a new concept,introduced by Tulunay(2017).It offers non-parametric methods and a new geometric view to data analysis.In that p...Non-parametric methods are treasured in data analysis,particularly in finance.ST-metric is a new concept,introduced by Tulunay(2017).It offers non-parametric methods and a new geometric view to data analysis.In that paper,ST-metric concept has been applied to performance measures of portfolios.In this current paper,we purpose another ST-metric method for finding factor exposures in the five-style-factors model.Here the style factors are value,size,minimum volatility,quality and momentum.The main idea is to find the factor exposures(weights)of the five-factors-model by minimizing the ST-metric between benchmark returns and the constructed factor model returns.We compare ST-metric method with Tracking Error method(TE-method)which is used for factor analysis of major indexes,decomposed into the style factors(tradable via Exchange Traded Funds(ETFs))by Ang et al.(2018).We show that ST-metric method gives better estimation of the factor exposures(weights)than tracking error method,in general,and further how ST-metric values vary with respect to fluctuations.This explains the reason behind the efficiency of the ST-metric method.We support this idea with empirical evidences.展开更多
基金supported by the National Science and Technology Major Project of China(No.J2019-Ⅲ-0009-0053)。
文摘The serpentine convergent-divergent nozzle represents an optimal configuration for nextgeneration fighter aircraft characterized by low detectability and high thrust-to-weight ratio.In contrast to the serpentine convergent nozzle,such configuration offers increased design flexibility with additional parameters,leading to heightened interactions among these parameters.As such,it is crucial to reveal the influence of design parameters on the aerodynamic performance of the serpentine convergent-divergent nozzle and the multifactor interaction,as well as its mechanism.Therefore,the influence,interaction and sensitivity of parameters on the aerodynamic performance of the nozzle were numerically investigated using the orthogonal test method.Additionally,the influence mechanism of the convergence angle,throat aspect ratio,and axial length to inlet diameter on the flow characteristics of the nozzle was investigated in detail.The results show that the convergence angle is identified as the main factor affecting the aerodynamic parameters of the nozzle.As the convergence angle increases,the thrust coefficient,total pressure recovery coefficient and discharge coefficient gradually decrease.The interaction between throat aspect ratio and other parameters is obvious.Different design parameters affect the local loss and the friction loss by affecting the curvature and wetted perimeter area,resulting in different aerodynamic characteristics of serpentine convergent-divergent nozzle.
基金Supported by Xiao-Ping Chen Foundation for The Development of Science and Technology of Hubei Province,No.CXPJJH122002-061.
文摘BACKGROUND Gallbladder cancer(GBC)is the most common malignant tumor of the biliary system,and is often undetected until advanced stages,making curative surgery unfeasible for many patients.Curative surgery remains the only option for long-term survival.Accurate postsurgical prognosis is crucial for effective treatment planning.tumor-node-metastasis staging,which focuses on tumor infiltration,lymph node metastasis,and distant metastasis,limits the accuracy of prognosis.Nomograms offer a more comprehensive and personalized approach by visually analyzing a broader range of prognostic factors,enhancing the precision of treatment planning for patients with GBC.AIM A retrospective study analyzed the clinical and pathological data of 93 patients who underwent radical surgery for GBC at Peking University People's Hospital from January 2015 to December 2020.Kaplan-Meier analysis was used to calculate the 1-,2-and 3-year survival rates.The log-rank test was used to evaluate factors impacting prognosis,with survival curves plotted for significant variables.Single-factor analysis revealed statistically significant differences,and multivariate Cox regression identified independent prognostic factors.A nomogram was developed and validated with receiver operating characteristic curves and calibration curves.Among 93 patients who underwent radical surgery for GBC,30 patients survived,accounting for 32.26%of the sample,with a median survival time of 38 months.The 1-year,2-year,and 3-year survival rates were 83.87%,68.82%,and 53.57%,respectively.Univariate analysis revealed that carbohydrate antigen 19-9 expre-ssion,T stage,lymph node metastasis,histological differentiation,surgical margins,and invasion of the liver,ex-trahepatic bile duct,nerves,and vessels(P≤0.001)significantly impacted patient prognosis after curative surgery.Multivariate Cox regression identified lymph node metastasis(P=0.03),histological differentiation(P<0.05),nerve invasion(P=0.036),and extrahepatic bile duct invasion(P=0.014)as independent risk factors.A nomogram model with a concordance index of 0.838 was developed.Internal validation confirmed the model's consistency in predicting the 1-year,2-year,and 3-year survival rates.CONCLUSION Lymph node metastasis,tumor differentiation,extrahepatic bile duct invasion,and perineural invasion are independent risk factors.A nomogram based on these factors can be used to personalize and improve treatment strategies.
基金supported by the Construction of Prevention and Treatment System of Geriatric Syndromes Focusing on Disability and Dementia(No.21-1-2-2-zyyd-nsh)。
文摘Objective This study aimed to explore the association of single nucleotide polymorphisms(SNP)in the matrix metalloproteinase 2(MMP-2)signaling pathway and the risk of vascular senescence(VS).Methods In this cross-sectional study,between May and November 2022,peripheral venous blood of151 VS patients(case group)and 233 volunteers(control group)were collected.Fourteen SNPs were identified in five genes encoding the components of the MMP-2 signaling pathway,assessed through carotid-femoral pulse wave velocity(cf PWV),and analyzed using multivariate logistic regression.The multigene influence on the risk of VS was assessed using multifactor dimensionality reduction(MDR)and generalized multifactor dimensionality regression(GMDR)modeling.Results Within the multivariate logistic regression models,four SNPs were screened to have significant associations with VS:chemokine(C-C motif)ligand 2(CCL2)rs4586,MMP2 rs14070,MMP2rs7201,and MMP2 rs1053605.Carriers of the T/C genotype of MMP2 rs14070 had a 2.17-fold increased risk of developing VS compared with those of the C/C genotype,and those of the T/T genotype had a19.375-fold increased risk.CCL2 rs4586 and MMP-2 rs14070 exhibited the most significant interactions.Conclusion CCL2 rs4586,MMP-2 rs14070,MMP-2 rs7201,and MMP-2 rs1053605 polymorphisms were significantly associated with the risk of VS.
文摘Mastitis is a complex, multifactorial disease. Pathogens, cows and farmers （via management） all play a role. It is costly and annoying for the farmer and threatens the image of the entire dairy industry. Prevention and control of mastitis is based on multiple principles that have been known for a long time. To implement them successfully, they should be put forward by a motivated and motivating advisor that transfers the existing knowledge to the farmer. When the changes are data-driven, applied by an encouraged farmer through a farm-specific implementation, prevention and control of mastitis will be successful and result in happy cows, happy farmers, happy advisors, happy consumers, and a happy industry. Nationwide projects focussing on communication and transfer of existing knowledge in prevention and control are very helpful in reaching high numbers of farmers and advisors and harmonizing the message brought by different parties. This paper gives an overview of multifactorial approach of mastitis management and prevention with a focus on milking, bedding and data-analysis.
基金National Key Research and Development Program of China(2019YFD1100401)The Young Talent Program of Xi’an Jiaotong University(GG6J007)The Fundamental Research Funds for the Central Universities(2662021JC009)。
文摘Functional zoning is an important mechanism for achieving national park planning and management objective.Better functional zoning is of great significance to the protection of ecosystem legitimacy and integrity,the appropriate utilization of resources,community integration,and feasible management.In the present study,the proposed Qinghai Lake National Park is the research object.Based on the critical goal of ecological protection,the importance of ecosystem service functions and the ecological sensitivities were evaluated.The results showed that the ecosystem service functions and the ecological sensitivity of the whole region are high.Among them,lake,river and wetland as the most strictly protected ecosystems account for the highest proportion.Then this study divided the proposed Qinghai Lake National Park into five functional areas through grid calculations,spatial analysis and multifactor trade-off.The results indicated that the goal of functional zoning for national park is to maximize the overall utility of park protection value and its comprehensive functions based on its spatial units with different functions,management and control requirements.The zoning scheme addresses the lack of sustainable development in Qinghai Lake National Park due to ecological environmental changes and single-resource zoning with resource protection as the primary goal.This study can serve as a reference for spatial functional zoning methods of national land parks,nature reserves and other natural protected areas.
基金supported by the Chinese National Special Fund for Agro-scientific Research in the Public Interest (201003025 and 201103022)the National Key Research and Development Program of China (2018YFD0201004)the Discipline Construction Project of Liaoning Academy of Agricultural Sciences, China (2019DD082612)。
文摘The soybean aphid, Aphis glycines Matsumura(Hemiptera: Aphididae), is one of the greatest threats to soybean production, and both trend analysis and periodic analysis of its population dynamics are important for integrated pest management(IPM). Based on systematically investigating soybean aphid populations in the field from 2018 to 2020, this study adopted the inverse logistic model for the first time, and combined it with the classical logistic model to describe the changes in seasonal population abundance from colonization to extinction in the field. Then, the increasing and decreasing phases of the population fluctuation were divided by calculating the inflection points of the models, which exhibited distinct seasonal trends of the soybean aphid populations in each year. In addition, multifactor logistic models were then established for the first time, in which the abundance of soybean aphids in the field changed with time and relevant environmental conditions. This model enabled the prediction of instantaneous aphid abundance at a given time based on relevant meteorological data. Taken as a whole, the successful approaches implemented in this study could be used to build a theoretical framework for practical IPM strategies for controlling soybean aphids.
基金the National Key R&D Program of China(No.2017YFB0902705)
文摘Based on Wiener process model, a new approach for reliability evaluation of cross-linked polyethylene(XLPE) is proposed to improve the lifetime evaluation reliability of XLPE under multi-stressing conditions and study the failure probability distribution. In this paper, two accelerated aging tests are carried out under combined thermal and vibration conditions. The volume resistance degradation data of XLPE samples are tested with a24 h interval under the accelerated stressing conditions at(130℃, 12 m/s^2) and(150℃, 8.5 m/s^2), respectively.Nonlinear degradation data obtained from the experiment are transformed to linear intermediate-variable values using time scaling function, and then linearized degradation data are calculated and evaluated on the basis of linear Wiener process model. Considering traditional Arrhenius equation and inverse power criterion, parameters of the linear Wiener model are estimated according to the maximum likelihood function. The relationship curves on probability density and reliability are given, and the lifetime distribution of XLPE under different stressing conditions is also obtained for evaluating the reliability of XLPE insulation. Finally, the life expectancy of XLPE is 17.9 a under an allowance temperature of 90℃ and an actual vibration acceleration of 0.5 m/s^2. The approach and results in this paper may be used for reliability assessment of high-voltage multiple samples or apparatuses.
基金supported by Zhejiang Key Research and Development Program of China[No.2015C03039,No.20152013A01]Zhejiang Provincial Program for the Cultivation of High-level Innovative Health Talents,China+2 种基金Zhejiang Health Innovative Talent Training Project of Chinageneral scientific research project of Zhejiang Science and Technology Department of China[No.Y201941671]Natural Science Foundation of Zhejiang Provincial,China[LY18H260002]。
文摘Objective The effects of interactions between genetic and environmental factors on the noise-induced hearing loss(NIHL)are still unclear.This study aimed to assess interactions among gene polymorphisms,noise metrics,and lifestyles on the risk of NIHL.Methods A case-control study was conducted using 307 patients with NIHL and 307 matched healthy individuals from five manufacturing industries.General demographic data,lifestyle details,and noise exposure levels were recorded.The Kompetitive allele-specific polymerase chain reaction(KASP)was used to analyze the genotypes of 18 SNPs.Results GMDR model demonstrated a relevant interaction between NRN1 rs3805789 and CAT rs7943316(P=0.0107).Subjects with T allele of rs3805789 or T allele of rs7943316 had higher risks of NIHL than those with the SNP pair of rs3805789-CC and rs7943316-AA(P<0.05).There was an interaction among rs3805789,rs7943316,and kurtosis(P=0.0010).Subjects exposed to complex noise and carrying both rs3805789-CT and rs7943316-TT or rs3805789-CT/TT and rs7943316-AA had higher risks of NIHL than those exposed to steady noise and carrying both rs3805789-CC and rs7943316-AA(P<0.05).The best six-locus model involving NRN1 rs3805789,CAT rs7943316,smoking,video volume,physical exercise,and working pressure for the risk of NIHL was found to be the interaction(P=0.0010).An interaction was also found among smoking,video volume,physical exercise,working pressure,and kurtosis(P=0.0107).Conclusion Concurrence of NRN1 and CAT constitutes a genetic risk factor for NIHL.Complex noise exposure significantly increases the risk of NIHL in subjects with a high genetic risk score.Interactions between genes and lifestyles as well as noise metrics and lifestyles affect the risk of NIHL.
基金funded by the National Natural Science Foundation of China(41971038U20A2085+3 种基金32171559U21A2005)the Fundamental Research Funds of CAF(CAFYBB2020QB004CAFYBB2021ZW002)。
文摘Nighttime sap flow(Q_(n))is an important physiological activity under which trees manage drought stress.An in-depth understanding of the characteristics of Q_(n)and its response to environmental and canopy conditions are of significance for arid area forest and water management.This study measured daily sap flow(Q_(s))of a Larix principis-rupprechtii plantation in the Liupan Mountains,northwest China during the 2017-2019 growing seasons,and separated Q_(s)into daytime sap flow(Qd)and Q_(n).Meteorological conditions(reference evapotranspiration,ETref),canopy structure(leaf area index,LAI),and soil moisture(relative soil water content,RSWC)were considered as the main biophysical factors affecting Q_(n).The structural equation model and upper boundary line method determined the effects of compound and single factors on Q_(n)The daily mean Q_(n)values during the growing seasons in 2017,2018,and 2019 were 0.024,0.026,and 0.030 mm d-1,accounting for 6.2,11.2,and 10.1%of Q_(s),respectively.Q_(n)at different canopy development phases(leaf expanding,LG;leaf expanded,LD;and defoliation,DF)over three years was LD>LG>DF.Q_(n)increased with increasing ETref,whereas the ratio of Q_(n)to Q_(s)decreased.Q_(n)did not show regular variation in the three-year growing seasons under different soil moisture conditions.ETrefand LAI mainly controlled Q_(n)by affecting Qd,whereas RSWC had no significant effect on Q_(n).Q_(n)had a positive and linear relationship with LAI and a quadratic relationship with ETref.Both explained 40%of variation in Q_(n)Meteorological and canopy conditions are important factors affecting Q_(n)on the semi-humid study site.The application of the Q_(n)model coupled with the impact of ETrefand LAI furthers understanding of the impacts of climate and forest structure change on Q_(n).
文摘Objective: To understand the status quo of PICC Catheter-associated Skin Impairment (CASI) in some hospitals at all levels in Jingzhou city, and to explore the risk factors for PICC Catheter-associated Skin Impairment. Methods: From June 2019 to July 2020, a self-made questionnaire for CASI status was used to facilitate the extraction of CASI patients in PICC in some hospitals at all levels in Jingzhou city. Local skin lesions were collected and classified during PICC maintenance, and the damage types, occurrence frequency and related influencing factors of CASI were counted to identify independent risk factors. Results: In this study, there were 173 cases of CASI in PICC’s patients including local infection 56.1% (97/173), exudation at the puncture site 16.8% (29/173), irritant dermatitis 21.4% (37/173), allergic dermatitis 4.6% (8/173), and tension injury 1.2% (2/173). After univariate analysis, there were statistically significant differences between CASI occurrence type and duration of catheter wear, age, underlying disease, skin moisture and hyperhidrosis, PICC maintenance as required, hospital grade maintenance and intermittent chemotherapy (P < 0.05). Then, disordered multiple Logistic regression analysis was performed, and exudation at the puncture site was used as the reference group. The results showed that patients with PICC were more likely to have CASI if they were aged, long catheter time, had diabetes, had moist and sweaty skin, and were in the intermittent stage of chemotherapy. Conclusion: The incidence of CASI is high in patients aged 70 - 79 years, and local infection is the most common. PICC’s patients with diabetes are at high risk of CASI. PICC’s patients with excessive sweating are more likely to have CASI. The intermittent stage of chemotherapy is the excessive CASI;time with tube affects CASI occurrence.
基金Supported by the National Natural Science Foundation of China(61872147,61761023).
文摘Process integration method is used to establish a composite model to perform computations of hybrid models for water quality assessment of Haihe River, and a resolution is presented to clear the long-term obscurity about the differences between single-factor assessment(SFA) and multifactor assessment(MFA) of water quality in this paper. Symbolic models were introduced to describe the types and orders of computations involved in SFA and such MFAs as Nemerow comprehensive index(NCI) and fuzzy comprehensive assessment(FCA). Facilitated by paired t-tests, the composite model of absolute distance(AD) was established to test the differences between SFA and MFAs on four water quality indicators(WQI). Matlab(R14) programs for these models were developed to perform integrative computations on 3 217 batches of water data obtained from seven monitoring sites of Haihe River from 2008 to 2017. Paired t-tests show that results of our SFA model(SFA-4) are not significantly different(p=0.926) from that of SFA based on all WQI, however, extremely significantly different from results of NCI(p=0) and FCA(p=0). SFA-4 is proved by AD model to be farther away from FCA(AD-S→F=1.075) than from NCI(AD-S→N=0.634). More than proving the deduction of SFA≥NCI≥FCA in most cases(p=0.885), the results from AD show that MFAs approach SFA when surface water becomes good(SFA=1) or worst(SFA=6), whereas depart to the farthest distance from SFA when surface water becomes worse(SFA=3). To sum up, the integrative computations involved in AD model on the water data are effective and efficient(improved by 44.2%). Furthermore, AD model shows the differences between SFA and MFAs clearly.
文摘The COVID-19 outbreak and its medical distancing phenomenon have effectively turned the global healthcare challenge into an opportunity for Telecare Medical Information Systems.Such systems employ the latest mobile and digital technologies and provide several advantages like minimal physical contact between patient and healthcare provider,easy mobility,easy access,consistent patient engagement,and cost-effectiveness.Any leakage or unauthorized access to users’medical data can have serious consequences for any medical information system.The majority of such systems thus rely on biometrics for authenticated access but biometric systems are also prone to a variety of attacks like spoong,replay,Masquerade,and stealing of stored templates.In this article,we propose a new cancelable biometric approach which has tentatively been named as“Expression Hash”for Telecare Medical Information Systems.The idea is to hash the expression templates with a set of pseudo-random keys which would provide a unique code(expression hash).This code can then be serving as a template for verication.Different expressions would result in different sets of expression hash codes,which could be used in different applications and for different roles of each individual.The templates are stored on the server-side and the processing is also performed on the server-side.The proposed technique is a multi-factor authentication system and provides advantages like enhanced privacy and security without the need for multiple biometric devices.In the case of compromise,the existing code can be revoked and can be directly replaced by a new set of expression hash code.The well-known JAFFE(The Japanese Female Facial Expression)dataset has been for empirical testing and the results advocate for the efcacy of the proposed approach.
基金The National Key Research and Development Plan of China(No.2018YFB0505103)the National Natural Science Foundation of China(No.61873064)。
文摘To realize the automatic detection of solar radio burst(SRB)intensity,detection based on a modified multifactor support vector machine(SVM)algorithm is proposed.First,the influence of SRB on global navigation satellite system(GNSS)signals is analyzed.Feature vectors,which can reflect the SRB intensity of stations,are also extracted.SRB intensity is classified according to the solar radio flux,and different class labels correspond to different SRB intensity types.The training samples are composed of feature vectors and their corresponding class labels.Second,training samples are input into SVM classifiers to one-against-one training to obtain the optimal classification models.Finally,the optimal classification model is synthesized into a modified multifactor SVM classifier,which is used to automatically detect the SRB intensity of new data.Experimental results indicate that for historical SRB events,the average accuracy of SRB intensity detection is greater than 90%when the solar incident angle is higher than 20°.Compared with other methods,the proposed method considers many factors with higher accuracy and does not rely on radio telescopes,thereby saving cost.
文摘 Chronic heart failure (CHF) is a clinical syndrome as a common pathway at the end stage of cardiac diseases of different etiologies, and it is currently the only cardiovascular disease with an increasing prevalence in the developed countries. In the United States, the prevalence of CHF at age 50 years is 1.0%, whereas it reaches 7.5% at age 80years. In the United Kingdom, the prevalence of CHF is5.0% at age 60-70 years, and 10-20% at age 80 years. The situation is similar in Italy and Portugal. Despite being a developing country in Asia, China has experienced rapid progress in acquiring medical knowledge and advancing techniques in recent years. Due to the markedly declined mortality of acute myocardial infarction (AMI) as well as the aging of Chinese population, about four million Chinese have CHF with a prevalence of 0.9%, most of whom are 60 years of age and older.……
基金This project is supported by the State Administration of Traditional Chinese Medicine(No.7-21).
文摘Objective:To analyze the syndrome characteristics in patients with chronic persistent asthma.Methods:365 patients(121 males,244 females,60.829.1 years old)with chronic persistent asthma were enrolled in this cross-sectional study.The information of syndrome,symptoms,signs,tongue coating and pulse were collected from all patients.The syndrome characteristics of chronic persistent asthma were examined through the multifactor dimensionality reduction(MDR)analysis and the results were verified by the Chi-square test.Results:The results of the MDR analysis and the Chi-square test showed the following positive correlation of the interaction among:the deficiency syndrome of the lung and spleen and deep pulse,disinclination to talk due to lack of qi,fatigue,lassitude and thick tongue coating;the deficiency syndrome of the lung and kidney and dizziness and disinclination to talk due to lack of qi,fatigue,lassitude and pallid complexion;the syndrome of phlegm-heat obstructing the lung and rapid pulse,abdominal distension,disinclination to talk due to lack of qi,frequent urination and lassitude;the syndrome of phlegm-dampness obstructing the lung and disinclination to talk due to lack of qi,greasy coating,fatigue and lassitude.(P<.05 for all).Conclusion:The syndrome of chronic persistent asthma is characterized by fatigue and lassitude due to dysfunction of the lung,spleen and kidney.
文摘This study investigates the effects of changes in local macroeconomic risk factors on returns on the banking,chemicals,insurance,telecommunication,and utilities industries in the U.S.market.Using a multifactor pricing model and data from 1998:01 to 2017:12,empirical results show that the banking,chemical,and telecommunication industries show more differences in their stock reactions to local macroeconomic risk factors.The insurance and telecommunication industries do not react significantly to risk factors.However,all the industries show strong reactions to local market portfolio.
文摘We develop various statistical methods important for multidimensional genetic data analysis. Theorems justifying application of these methods are established. We concentrate on the multifactor dimensionality reduction, logic regression, random forests, stochastic gradient boosting along with their new modifications. We use complementary approaches to study the risk of complex diseases such as cardiovascular ones. The roles of certain combinations of single nucleotide polymorphisms and non-genetic risk factors are examined. To perform the data analysis concerning the coronary heart disease and myocardial infarction the Lomonosov Moscow State University supercomputer “Chebyshev” was employed.
文摘Xu deep volcanic gas reservoir is typical of complex lithology, severe inhomogeneity, big difficulty to extract. Pressure sensitivity always exists in gas reservoirs. Prorating production is too high or low, causing problems, as for the energy loss, reservoir damage, bottom effusion, thus lowing the gas productivity and affecting development benefit. So it have to research on a new reasonably production proration method considering multi influential factors. It is a reasonably production proration method considering multi influential factors in Xu gas reservoir, with guidelines such as capacity use, pressure draw down, gas recovery rate, water out and throughout water data is reasonably, so we can long term use it to guide gas field exploitation.
文摘Cloud computing(CC)is an advanced technology that provides access to predictive resources and data sharing.The cloud environment represents the right type regarding cloud usage model ownership,size,and rights to access.It introduces the scope and nature of cloud computing.In recent times,all processes are fed into the system for which consumer data and cache size are required.One of the most security issues in the cloud environment is Distributed Denial of Ser-vice(DDoS)attacks,responsible for cloud server overloading.This proposed sys-tem ID3(Iterative Dichotomiser 3)Maximum Multifactor Dimensionality Posteriori Method(ID3-MMDP)is used to overcome the drawback and a rela-tively simple way to execute and for the detection of(DDoS)attack.First,the pro-posed ID3-MMDP method calls for the resources of the cloud platform and then implements the attack detection technology based on information entropy to detect DDoS attacks.Since because the entropy value can show the discrete or aggregated characteristics of the current data set,it can be used for the detection of abnormal dataflow,User-uploaded data,ID3-MMDP system checks and read risk measurement and processing,bug ratingfile size changes,orfile name changes and changes in the format design of the data size entropy value.Unique properties can be used whenever the program approaches any data error to detect abnormal data services.Finally,the experiment also verifies the DDoS attack detection capability algorithm.
文摘Non-parametric methods are treasured in data analysis,particularly in finance.ST-metric is a new concept,introduced by Tulunay(2017).It offers non-parametric methods and a new geometric view to data analysis.In that paper,ST-metric concept has been applied to performance measures of portfolios.In this current paper,we purpose another ST-metric method for finding factor exposures in the five-style-factors model.Here the style factors are value,size,minimum volatility,quality and momentum.The main idea is to find the factor exposures(weights)of the five-factors-model by minimizing the ST-metric between benchmark returns and the constructed factor model returns.We compare ST-metric method with Tracking Error method(TE-method)which is used for factor analysis of major indexes,decomposed into the style factors(tradable via Exchange Traded Funds(ETFs))by Ang et al.(2018).We show that ST-metric method gives better estimation of the factor exposures(weights)than tracking error method,in general,and further how ST-metric values vary with respect to fluctuations.This explains the reason behind the efficiency of the ST-metric method.We support this idea with empirical evidences.
