Telomeres, which are found at the ends of eukaryotic chromosomes, are composed of tandem arrays of repetitive sequences and safeguard genomic stability. Previous studies have revealed that telomeric repeats are also p...Telomeres, which are found at the ends of eukaryotic chromosomes, are composed of tandem arrays of repetitive sequences and safeguard genomic stability. Previous studies have revealed that telomeric repeats are also present at internal chromosomal loci in many eukaryotes. However, the biological role of these interstitial telomeric sequences (ITSs) remains unknown. The integrity of telomeric length and chromatin structure is required for telomere stability. However, the study of these telomeric features can be impeded by the presence of ITSs. Frequently cutting restriction enzymes have been revealed to be very useful tools for the study of the length and chromatin structure of telomeres independent of the presence of ITSs.展开更多
1.Where did the Olympic gamescome from?There are many different stories about the be-ginning of the Olympics.One myth says that the guardians of the infantgod Zeus held the first footrace,or that Zeus himselfstarted t...1.Where did the Olympic gamescome from?There are many different stories about the be-ginning of the Olympics.One myth says that the guardians of the infantgod Zeus held the first footrace,or that Zeus himselfstarted the Games to celebrate his victory over his fa-ther Cronus for control of the world.Another tradi-tion states that after the Greek hero Pelops won achariot race against King Oenomaus to marry Oeno-展开更多
Risperidone is a safe second-generation antipsychotic which is rarely associated with the emergence of a few adverse effects,such as oral lesions and stomatitis.We report the case of a 77-year-old woman affected by a ...Risperidone is a safe second-generation antipsychotic which is rarely associated with the emergence of a few adverse effects,such as oral lesions and stomatitis.We report the case of a 77-year-old woman affected by a neurocognitive disorder with psychotic features and treated with risperidone 2 mg/day.After 1 week,she showed a burning mouth syndrome with oral lesions and risperidone was discontinued.Antipsychotic-induced oral ulcerations may be caused by the reduction of saliva protection with minor adverse effects related to oral movement disorders or impairment of the bacterial flora of saliva.展开更多
Background Mizoribine (MZR) is an immunosuppressant used to treat adult nephropathy.There is little experience with the drug in treating Chinese children with frequently relapsing nephrotic syndrome (FRNS).We investig...Background Mizoribine (MZR) is an immunosuppressant used to treat adult nephropathy.There is little experience with the drug in treating Chinese children with frequently relapsing nephrotic syndrome (FRNS).We investigated the efficacy and safety for treating MZR with FRNS.Furthermore,the relationship between efficacy and serum concentration was investigated.Methods A prospective multicenter observational 12-month study was performed for evaluating the usefulness of MZR with FRNS.Serum MZR concentration was measured,and the relationships between pharmacokinetic parameters (Cmax,AUC),number of relapses,and urinary protein were evaluated.Results Eighty-two pediatric patients from four hospitals were treated with MZR and prednisone.MZR treatment significantly reduced the number of relapses and steroid doses.A correlation between pharmacokinetic parameters and relapses was observed,which fits well with the sigmoidal Emax model.Even in the relationship between pharmacokinetic parameters and urinary proteins,it was recognized that there was a threshold in the pharmacokinetic parameters for the therapeutic effect similar to the results obtained with the sigmoidal Emax model.Eleven patients (13.4%) experienced mild adverse events.Conclusions MZR therapy was effective in reducing the number of relapses and steroid doses.No severe adverse reactions were observed.Therapeutically effective serum concentrations were estimated to be Cmax > about 2 μg/mL or AUC > about 10 lag h/mL.MZR and steroid treatment were effective and safe for pediatric FRNS.展开更多
For the titanium tube industry in 2016,the widespread loss in the industry in 2015 will quicken the adjustment pace of product structure in the tube market,and create new industrial situation;furthermore,the'One B...For the titanium tube industry in 2016,the widespread loss in the industry in 2015 will quicken the adjustment pace of product structure in the tube market,and create new industrial situation;furthermore,the'One Belt,One Road'plan in the'Thirteenth Five Year'Plan will also boost demand in the tube market.Meanwhile,due to the tremendous base in capacity and output,and excessively long absorption time;coupled with heavy展开更多
The development of sarcopenia in patients with chronic liver disease has been recognized as a predictor of poor outcome.Sarcopenia,or the progressive loss of skeletal muscle mass begins to manifest in the early stages...The development of sarcopenia in patients with chronic liver disease has been recognized as a predictor of poor outcome.Sarcopenia,or the progressive loss of skeletal muscle mass begins to manifest in the early stages of chronic liver disease and worsens with progression to advanced liver disease with a prevalence approaching 60%in patients with end-stage liver disease(1).展开更多
Animal medicines,which boast a lengthy history as treasures of traditional Chinese medicine(TCM),frequently encounter safety challenges stemming from the accumulation of heavy metals and harmful elements,such as arsen...Animal medicines,which boast a lengthy history as treasures of traditional Chinese medicine(TCM),frequently encounter safety challenges stemming from the accumulation of heavy metals and harmful elements,such as arsenic(As)[1].The toxicity of As differs by species,especially inorganic arsenic(iAs),and current methods for assessing herbal risks based on total arsenic(tAs)content are insufficient[2].To address this,studies have focused on As contamination in TCMs,especially leeches.Widely used for anticoagulant and other pharmacological activities,leeches are susceptible to water contamination and high As levels due to immature farming technology[3].The aim of this study was to comprehensively analyze the distribution of tAs and toxic elements in leeches from multiple sources and batches.We used advanced analytical techniques(e.g.,liquid chromatography-inductively coupled plasma mass spectrometry(LC-ICPMS))to accurately identify As forms.This study aims to investigate the biological effects at the exposure point through in vitro experiments(simulating physiological conditions)and assess the potential clinical risks associated with iAs.展开更多
通过坚持每周健身六天,汤姆·凯里奇成功改善了身心健康状况。Celebrated chef and Great British Menu judge Tom Kerridge hits the gym six days a week to maintain his mental and physical health.The culinary star,who is a...通过坚持每周健身六天,汤姆·凯里奇成功改善了身心健康状况。Celebrated chef and Great British Menu judge Tom Kerridge hits the gym six days a week to maintain his mental and physical health.The culinary star,who is a two‑Michelin‑starred pub owner,explained his switch from swimming to gym workouts was due to the frequent travel his job needs,noting the challenge of finding hotels with pools.展开更多
China and Vietnam have maintained close theatrical exchange.A group of Vietnamese students studied at the Central Academy of Drama and the National Academy of Chinese Theatre Arts(NACTA)of China in the 1950s and’60s....China and Vietnam have maintained close theatrical exchange.A group of Vietnamese students studied at the Central Academy of Drama and the National Academy of Chinese Theatre Arts(NACTA)of China in the 1950s and’60s.The past decade has witnessed steadily improving relations between the two countries.Their cultural exchange,especially in theatrical arts,has become increasingly fruitful in three distinct ways.展开更多
TarGuess-I is a leading model utilizing Personally Identifiable Information for online targeted password guessing.Due to its remarkable guessing performance,the model has drawn considerable attention in password secur...TarGuess-I is a leading model utilizing Personally Identifiable Information for online targeted password guessing.Due to its remarkable guessing performance,the model has drawn considerable attention in password security research.However,through an analysis of the vulnerable behavior of users when constructing passwords by combining popular passwords with their Personally Identifiable Information,we identified that the model fails to consider popular passwords and frequent substrings,and it uses overly broad personal information categories,with extensive duplicate statistics.To address these issues,we propose an improved password guessing model,TGI-FPR,which incorporates three semantic methods:(1)identification of popular passwords by generating top 300 lists from similar websites,(2)use of frequent substrings as new grammatical labels to capture finer-grained password structures,and(3)further subdivision of the six major categories of personal information.To evaluate the performance of the proposed model,we conducted experiments on six large-scale real-world password leak datasets and compared its accuracy within the first 100 guesses to that of TarGuess-I.The results indicate a 2.65%improvement in guessing accuracy.展开更多
In wind and solar renewable-dominant hybrid alternating current/direct current(AC/DC)power systems,the active power of high-voltage direct current(HVDC)system is significantly limited by the security and stability eve...In wind and solar renewable-dominant hybrid alternating current/direct current(AC/DC)power systems,the active power of high-voltage direct current(HVDC)system is significantly limited by the security and stability events caused by cascading failures.To identify critical lines in cascading failures,a rapid risk assessment method is proposed based on the gradient boosting decision tree(GBDT)and frequent pat-tern growth(FP-Growth)algorithms.First,security and stability events triggered by cascading failures are analyzed to explain the impact of cascading failures on the maximum DC power.Then,a cascading failure risk index is defined,focusing on the DC power being limited.To handle the strong nonlinear relationship between the maximum DC power and cascading failures,a GBDT with an update strategy is utilized to rapidly predict the maximum DC power under uncertain operating conditions.Finally,the FP-Growth algorithm is improved to mine frequent patterns in cascading failures.The importance index for each fault in a frequent pattern is defined by evaluating its impact on cascading failures,enabling the identification of critical lines.Simulation results of a modified Ningxia–Shandong hybrid AC/DC system in China demonstrate that the proposed method can rapidly assess the risk of cascading failures and effectively identify critical lines.展开更多
In this paper, we propose an efficient algorithm, called FFP-Growth (shortfor fast FP-Growth) , to mine frequent itemsets. Similar to FP-Growth, FFP-Growth searches theFP-tree in the bottom-up order, but need not cons...In this paper, we propose an efficient algorithm, called FFP-Growth (shortfor fast FP-Growth) , to mine frequent itemsets. Similar to FP-Growth, FFP-Growth searches theFP-tree in the bottom-up order, but need not construct conditional pattern bases and sub-FP-trees,thus, saving a substantial amount of time and space, and the FP-tree created by it is much smallerthan that created by TD-FP-Growth, hence improving efficiency. At the same time, FFP-Growth can beeasily extended for reducing the search space as TD-FP-Growth (M) and TD-FP-Growth (C). Experimentalresults show that the algorithm of this paper is effective and efficient.展开更多
Dear editor,Patients frequently visit the emergency room with acute chest pain.While some potentially life-threatening disorders may cause the pain,in approximately 80%of cases,the chest pain source is benign,and musc...Dear editor,Patients frequently visit the emergency room with acute chest pain.While some potentially life-threatening disorders may cause the pain,in approximately 80%of cases,the chest pain source is benign,and musculoskeletal chest pain accounts for nearly 20%– 50%of those cases.^[1–6]Thus,pain caused by benign and pathological conditions of the chest wall encountered in the emergency department is sometimes incorrectly attributed to angina pectoris or pleuritic and other serious cardiopulmonary diseases.展开更多
Free spanning pipelines are suspended between two points on an uneven seaffoor. The variations of structural conditions, such as the changes in soil property, flow velocity, axial force and span length etc., directly ...Free spanning pipelines are suspended between two points on an uneven seaffoor. The variations of structural conditions, such as the changes in soil property, flow velocity, axial force and span length etc., directly affect working performance of the whole submarine pipeline system. But until now few researches have focused on condition identification for free span （CIFS）. A method to identify the operational conditions of free spanning submarine pipelines based on vibration measurements is proposed in this paper. Firstly, the ill-posedness of CIFS is analyzed in detail. Secondly, the framework for CIFS based on the nonlinear kernel discriminant analysis （KDA） is established. Thirdly, the internal structural characteristics of natural frequencies, normalized frequencies and frequency change ratios are studied. And then the condition feature vector for CIFS is extracted by use of the vibration measurements. Finally, the validity of the proposed approach is evaluated by a case study. The results demonstrate that the proposed approach can effectively identify each condition of free span when condition variation occurs even if under measurement noise. It is concluded that the proposed method is a promising tool for CIFS in real applications.展开更多
A new algorithm based on an FC-tree （frequent closed pattern tree） and a max-FCIA （maximal frequent closed itemsets algorithm） is presented, which is used to mine the frequent closed itemsets for solving memory an...A new algorithm based on an FC-tree （frequent closed pattern tree） and a max-FCIA （maximal frequent closed itemsets algorithm） is presented, which is used to mine the frequent closed itemsets for solving memory and time consuming problems. This algorithm maps the transaction database by using a Hash table,gets the support of all frequent itemsets through operating the Hash table and forms a lexicographic subset tree including the frequent itemsets.Efficient pruning methods are used to get the FC-tree including all the minimum frequent closed itemsets through processing the lexicographic subset tree.Finally,frequent closed itemsets are generated from minimum frequent closed itemsets.The experimental results show that the mapping transaction database is introduced in the algorithm to reduce time consumption and to improve the efficiency of the program.Furthermore,the effective pruning strategy restrains the number of candidates,which saves space.The results show that the algorithm is effective.展开更多
The target reliability indices of the foundation structures of sea-crossing bridges on the serviceability limit state （SLS） are different from those of common bridges due to their different surroundings. Consequentl...The target reliability indices of the foundation structures of sea-crossing bridges on the serviceability limit state （SLS） are different from those of common bridges due to their different surroundings. Consequently, three levels of the target reliability indices, which are 1.5, 2. 0 and 2. 3, respectively, for those structures on the SLS are suggested based on the Joint Committee on Structural Safety （JCSS） model code, and a new method of calibrating factors of live loads, which is based on the contribution ratio of tensile stresses of reinforcing bars produced by various loads to the maximum crack width of concrete, is proposed. Finally, the calibration of the reliability-based factors of the frequent value and the quasi-permanent value of live loads is conducted by the Joint Committee （JC） method through an actual design, and the indices are proved to be reasonable and the new method is proved to be feasible.展开更多
By analyzing the features of cold and warm summer of the northeast China during 1961-2002,the results showed the time from 1960s to late 1970s was the phase of cold summer took place,and the time from 1980s to early 1...By analyzing the features of cold and warm summer of the northeast China during 1961-2002,the results showed the time from 1960s to late 1970s was the phase of cold summer took place,and the time from 1980s to early 1990s was the phase of cold and warm summer alternately took place.After the middle and late period of 1990s,it was the concentrated occurrence period of warm summer.The cool and warm summer had the continuity and cluster occurrence characteristics.The frequency of the cool summer was more than the warm summer,and the abnormal degree of warm summer was stronger than the cool summer,and the influence scope was wide.The cool summer had 4 frequent occurrence centers,and the warm summer had 2 frequent occurrence centers,located at the mountain zone and the hills zone.Not only the cool summer was easy to appear,but also the warm summer was easy to happen in the west and the east of Heilongjiang province.Comparatively speaking,the cool summer was easier to appear in the Changbai Mountain area.展开更多
文摘Telomeres, which are found at the ends of eukaryotic chromosomes, are composed of tandem arrays of repetitive sequences and safeguard genomic stability. Previous studies have revealed that telomeric repeats are also present at internal chromosomal loci in many eukaryotes. However, the biological role of these interstitial telomeric sequences (ITSs) remains unknown. The integrity of telomeric length and chromatin structure is required for telomere stability. However, the study of these telomeric features can be impeded by the presence of ITSs. Frequently cutting restriction enzymes have been revealed to be very useful tools for the study of the length and chromatin structure of telomeres independent of the presence of ITSs.
文摘1.Where did the Olympic gamescome from?There are many different stories about the be-ginning of the Olympics.One myth says that the guardians of the infantgod Zeus held the first footrace,or that Zeus himselfstarted the Games to celebrate his victory over his fa-ther Cronus for control of the world.Another tradi-tion states that after the Greek hero Pelops won achariot race against King Oenomaus to marry Oeno-
文摘Risperidone is a safe second-generation antipsychotic which is rarely associated with the emergence of a few adverse effects,such as oral lesions and stomatitis.We report the case of a 77-year-old woman affected by a neurocognitive disorder with psychotic features and treated with risperidone 2 mg/day.After 1 week,she showed a burning mouth syndrome with oral lesions and risperidone was discontinued.Antipsychotic-induced oral ulcerations may be caused by the reduction of saliva protection with minor adverse effects related to oral movement disorders or impairment of the bacterial flora of saliva.
文摘Background Mizoribine (MZR) is an immunosuppressant used to treat adult nephropathy.There is little experience with the drug in treating Chinese children with frequently relapsing nephrotic syndrome (FRNS).We investigated the efficacy and safety for treating MZR with FRNS.Furthermore,the relationship between efficacy and serum concentration was investigated.Methods A prospective multicenter observational 12-month study was performed for evaluating the usefulness of MZR with FRNS.Serum MZR concentration was measured,and the relationships between pharmacokinetic parameters (Cmax,AUC),number of relapses,and urinary protein were evaluated.Results Eighty-two pediatric patients from four hospitals were treated with MZR and prednisone.MZR treatment significantly reduced the number of relapses and steroid doses.A correlation between pharmacokinetic parameters and relapses was observed,which fits well with the sigmoidal Emax model.Even in the relationship between pharmacokinetic parameters and urinary proteins,it was recognized that there was a threshold in the pharmacokinetic parameters for the therapeutic effect similar to the results obtained with the sigmoidal Emax model.Eleven patients (13.4%) experienced mild adverse events.Conclusions MZR therapy was effective in reducing the number of relapses and steroid doses.No severe adverse reactions were observed.Therapeutically effective serum concentrations were estimated to be Cmax > about 2 μg/mL or AUC > about 10 lag h/mL.MZR and steroid treatment were effective and safe for pediatric FRNS.
文摘For the titanium tube industry in 2016,the widespread loss in the industry in 2015 will quicken the adjustment pace of product structure in the tube market,and create new industrial situation;furthermore,the'One Belt,One Road'plan in the'Thirteenth Five Year'Plan will also boost demand in the tube market.Meanwhile,due to the tremendous base in capacity and output,and excessively long absorption time;coupled with heavy
文摘The development of sarcopenia in patients with chronic liver disease has been recognized as a predictor of poor outcome.Sarcopenia,or the progressive loss of skeletal muscle mass begins to manifest in the early stages of chronic liver disease and worsens with progression to advanced liver disease with a prevalence approaching 60%in patients with end-stage liver disease(1).
基金supported by the National Natural Science Foundation of China(Grant No.:82404856)the National Key Research and Development Program of China(Grant No.:2023YFC3504100)the Key projects for Building a Scientific System for Drug Regulation,China(Project No.:RS2024Z006).
文摘Animal medicines,which boast a lengthy history as treasures of traditional Chinese medicine(TCM),frequently encounter safety challenges stemming from the accumulation of heavy metals and harmful elements,such as arsenic(As)[1].The toxicity of As differs by species,especially inorganic arsenic(iAs),and current methods for assessing herbal risks based on total arsenic(tAs)content are insufficient[2].To address this,studies have focused on As contamination in TCMs,especially leeches.Widely used for anticoagulant and other pharmacological activities,leeches are susceptible to water contamination and high As levels due to immature farming technology[3].The aim of this study was to comprehensively analyze the distribution of tAs and toxic elements in leeches from multiple sources and batches.We used advanced analytical techniques(e.g.,liquid chromatography-inductively coupled plasma mass spectrometry(LC-ICPMS))to accurately identify As forms.This study aims to investigate the biological effects at the exposure point through in vitro experiments(simulating physiological conditions)and assess the potential clinical risks associated with iAs.
文摘通过坚持每周健身六天,汤姆·凯里奇成功改善了身心健康状况。Celebrated chef and Great British Menu judge Tom Kerridge hits the gym six days a week to maintain his mental and physical health.The culinary star,who is a two‑Michelin‑starred pub owner,explained his switch from swimming to gym workouts was due to the frequent travel his job needs,noting the challenge of finding hotels with pools.
文摘China and Vietnam have maintained close theatrical exchange.A group of Vietnamese students studied at the Central Academy of Drama and the National Academy of Chinese Theatre Arts(NACTA)of China in the 1950s and’60s.The past decade has witnessed steadily improving relations between the two countries.Their cultural exchange,especially in theatrical arts,has become increasingly fruitful in three distinct ways.
基金supported by the Joint Funds of National Natural Science Foundation of China(Grant No.U23A20304)the Fund of Laboratory for Advanced Computing and Intelligence Engineering(No.2023-LYJJ-01-033)+1 种基金the Special Funds of Jiangsu Province Science and Technology Plan(Key R&D ProgramIndustryOutlook and Core Technologies)(No.BE2023005-4)the Science Project of Hainan University(KYQD(ZR)-21075).
文摘TarGuess-I is a leading model utilizing Personally Identifiable Information for online targeted password guessing.Due to its remarkable guessing performance,the model has drawn considerable attention in password security research.However,through an analysis of the vulnerable behavior of users when constructing passwords by combining popular passwords with their Personally Identifiable Information,we identified that the model fails to consider popular passwords and frequent substrings,and it uses overly broad personal information categories,with extensive duplicate statistics.To address these issues,we propose an improved password guessing model,TGI-FPR,which incorporates three semantic methods:(1)identification of popular passwords by generating top 300 lists from similar websites,(2)use of frequent substrings as new grammatical labels to capture finer-grained password structures,and(3)further subdivision of the six major categories of personal information.To evaluate the performance of the proposed model,we conducted experiments on six large-scale real-world password leak datasets and compared its accuracy within the first 100 guesses to that of TarGuess-I.The results indicate a 2.65%improvement in guessing accuracy.
基金supported by the National Key Research and Development Program of China"Key technologies for system stability and HVDC transmission of large-scale renewable energy generation base without conventional power support(2022YFB2402700)"the project of the State Grid Corporation of China(52272222001J).
文摘In wind and solar renewable-dominant hybrid alternating current/direct current(AC/DC)power systems,the active power of high-voltage direct current(HVDC)system is significantly limited by the security and stability events caused by cascading failures.To identify critical lines in cascading failures,a rapid risk assessment method is proposed based on the gradient boosting decision tree(GBDT)and frequent pat-tern growth(FP-Growth)algorithms.First,security and stability events triggered by cascading failures are analyzed to explain the impact of cascading failures on the maximum DC power.Then,a cascading failure risk index is defined,focusing on the DC power being limited.To handle the strong nonlinear relationship between the maximum DC power and cascading failures,a GBDT with an update strategy is utilized to rapidly predict the maximum DC power under uncertain operating conditions.Finally,the FP-Growth algorithm is improved to mine frequent patterns in cascading failures.The importance index for each fault in a frequent pattern is defined by evaluating its impact on cascading failures,enabling the identification of critical lines.Simulation results of a modified Ningxia–Shandong hybrid AC/DC system in China demonstrate that the proposed method can rapidly assess the risk of cascading failures and effectively identify critical lines.
文摘In this paper, we propose an efficient algorithm, called FFP-Growth (shortfor fast FP-Growth) , to mine frequent itemsets. Similar to FP-Growth, FFP-Growth searches theFP-tree in the bottom-up order, but need not construct conditional pattern bases and sub-FP-trees,thus, saving a substantial amount of time and space, and the FP-tree created by it is much smallerthan that created by TD-FP-Growth, hence improving efficiency. At the same time, FFP-Growth can beeasily extended for reducing the search space as TD-FP-Growth (M) and TD-FP-Growth (C). Experimentalresults show that the algorithm of this paper is effective and efficient.
文摘Dear editor,Patients frequently visit the emergency room with acute chest pain.While some potentially life-threatening disorders may cause the pain,in approximately 80%of cases,the chest pain source is benign,and musculoskeletal chest pain accounts for nearly 20%– 50%of those cases.^[1–6]Thus,pain caused by benign and pathological conditions of the chest wall encountered in the emergency department is sometimes incorrectly attributed to angina pectoris or pleuritic and other serious cardiopulmonary diseases.
基金supported by the Key Program of National Natural Science Foundation of China(GrantNo.50439010)the Main Program of the Ministry of Education of China(Grant No.305003)
文摘Free spanning pipelines are suspended between two points on an uneven seaffoor. The variations of structural conditions, such as the changes in soil property, flow velocity, axial force and span length etc., directly affect working performance of the whole submarine pipeline system. But until now few researches have focused on condition identification for free span （CIFS）. A method to identify the operational conditions of free spanning submarine pipelines based on vibration measurements is proposed in this paper. Firstly, the ill-posedness of CIFS is analyzed in detail. Secondly, the framework for CIFS based on the nonlinear kernel discriminant analysis （KDA） is established. Thirdly, the internal structural characteristics of natural frequencies, normalized frequencies and frequency change ratios are studied. And then the condition feature vector for CIFS is extracted by use of the vibration measurements. Finally, the validity of the proposed approach is evaluated by a case study. The results demonstrate that the proposed approach can effectively identify each condition of free span when condition variation occurs even if under measurement noise. It is concluded that the proposed method is a promising tool for CIFS in real applications.
基金The National Natural Science Foundation of China(No.60603047)the Natural Science Foundation of Liaoning ProvinceLiaoning Higher Education Research Foundation(No.2008341)
文摘A new algorithm based on an FC-tree （frequent closed pattern tree） and a max-FCIA （maximal frequent closed itemsets algorithm） is presented, which is used to mine the frequent closed itemsets for solving memory and time consuming problems. This algorithm maps the transaction database by using a Hash table,gets the support of all frequent itemsets through operating the Hash table and forms a lexicographic subset tree including the frequent itemsets.Efficient pruning methods are used to get the FC-tree including all the minimum frequent closed itemsets through processing the lexicographic subset tree.Finally,frequent closed itemsets are generated from minimum frequent closed itemsets.The experimental results show that the mapping transaction database is introduced in the algorithm to reduce time consumption and to improve the efficiency of the program.Furthermore,the effective pruning strategy restrains the number of candidates,which saves space.The results show that the algorithm is effective.
基金The National Natural Science Foundation of China (No.50538070).
文摘The target reliability indices of the foundation structures of sea-crossing bridges on the serviceability limit state （SLS） are different from those of common bridges due to their different surroundings. Consequently, three levels of the target reliability indices, which are 1.5, 2. 0 and 2. 3, respectively, for those structures on the SLS are suggested based on the Joint Committee on Structural Safety （JCSS） model code, and a new method of calibrating factors of live loads, which is based on the contribution ratio of tensile stresses of reinforcing bars produced by various loads to the maximum crack width of concrete, is proposed. Finally, the calibration of the reliability-based factors of the frequent value and the quasi-permanent value of live loads is conducted by the Joint Committee （JC） method through an actual design, and the indices are proved to be reasonable and the new method is proved to be feasible.
文摘By analyzing the features of cold and warm summer of the northeast China during 1961-2002,the results showed the time from 1960s to late 1970s was the phase of cold summer took place,and the time from 1980s to early 1990s was the phase of cold and warm summer alternately took place.After the middle and late period of 1990s,it was the concentrated occurrence period of warm summer.The cool and warm summer had the continuity and cluster occurrence characteristics.The frequency of the cool summer was more than the warm summer,and the abnormal degree of warm summer was stronger than the cool summer,and the influence scope was wide.The cool summer had 4 frequent occurrence centers,and the warm summer had 2 frequent occurrence centers,located at the mountain zone and the hills zone.Not only the cool summer was easy to appear,but also the warm summer was easy to happen in the west and the east of Heilongjiang province.Comparatively speaking,the cool summer was easier to appear in the Changbai Mountain area.
