Due to the fact that semantic role labeling (SRL) is very necessary for deep natural language processing, a method based on conditional random fields (CRFs) is proposed for the SRL task. This method takes shallow ...Due to the fact that semantic role labeling (SRL) is very necessary for deep natural language processing, a method based on conditional random fields (CRFs) is proposed for the SRL task. This method takes shallow syntactic parsing as the foundation, phrases or named entities as the labeled units, and the CRFs model is trained to label the predicates' semantic roles in a sentence. The key of the method is parameter estimation and feature selection for the CRFs model. The L-BFGS algorithm was employed for parameter estimation, and three category features: features based on sentence constituents, features based on predicate, and predicate-constituent features as a set of features for the model were selected. Evaluation on the datasets of CoNLL-2005 SRL shared task shows that the method can obtain better performance than the maximum entropy model, and can achieve 80. 43 % precision and 63. 55 % recall for semantic role labeling.展开更多
The use of hidden conditional random fields (HCRFs) for tone modeling is explored. The tone recognition performance is improved using HCRFs by taking advantage of intra-syllable dynamic, inter-syllable dynamic and d...The use of hidden conditional random fields (HCRFs) for tone modeling is explored. The tone recognition performance is improved using HCRFs by taking advantage of intra-syllable dynamic, inter-syllable dynamic and duration features. When the tone model is integrated into continuous speech recognition, the discriminative model weight training (DMWT) is proposed. Acoustic and tone scores are scaled by model weights discriminatively trained by the minimum phone error (MPE) criterion. Two schemes of weight training are evaluated and a smoothing technique is used to make training robust to overtraining problem. Experiments show that the accuracies of tone recognition and large vocabulary continuous speech recognition (LVCSR) can be improved by the HCRFs based tone model. Compared with the global weight scheme, continuous speech recognition can be improved by the discriminative trained weight combinations.展开更多
In order to avoid the noise and over fitting and further improve the limited classification performance of the real decision tree, a traffic incident detection method based on the random forest algorithm is presented....In order to avoid the noise and over fitting and further improve the limited classification performance of the real decision tree, a traffic incident detection method based on the random forest algorithm is presented. From the perspective of classification strength and correlation, three experiments are performed to investigate the potential application of random forest to traffic incident detection: comparison with a different number of decision trees; comparison with different decision trees; comparison with the neural network. The real traffic data of the 1-880 database is used in the experiments. The detection performance is evaluated by the common criteria including the detection rate, the false alarm rate, the mean time to detection, the classification rate and the area under the curve of the receiver operating characteristic (ROC). The experimental results indicate that the model based on random forest can improve the decision rate, reduce the testing time, and obtain a higher classification rate. Meanwhile, it is competitive compared with multi-layer feed forward neural networks (MLF).展开更多
Let X (t)(t∈R^N) be a d-dimensional fractional Brownian motion. A contiunous function f:R^N→R^d is called a polar function of X(t)(t∈R^N) if P{ t∈R^N\{0},X(t)=t(t)}=0. In this paper, the characteristies of the cla...Let X (t)(t∈R^N) be a d-dimensional fractional Brownian motion. A contiunous function f:R^N→R^d is called a polar function of X(t)(t∈R^N) if P{ t∈R^N\{0},X(t)=t(t)}=0. In this paper, the characteristies of the class of polar functions are studied. Our theorem 1 improves the previous results of Graversen and Legall. Theorem2 solves a problem of Legall (1987) on Brownian motion.展开更多
This paper focuses on the analysis of running conditions and machining processes of conical cam with oscillating follower. We point out the common errors existing in the design and machining of the widely used plane e...This paper focuses on the analysis of running conditions and machining processes of conical cam with oscillating follower. We point out the common errors existing in the design and machining of the widely used plane expansion method of conical cam trough-out line. We show that the motion can be divided into two parts, i.e. the oscillating motion of oscillating bar and the rotary motion of oscillating bar relative to the conical cam. By increasing the rotary motion of oscillating bar, the motion path of tapered roller on oscillating bar (i.e. contour surface of conical cam) can be expanded on the cylinder. Based on these analyses, we present a creative and effective designing and machining method for 3D curve expansion of conical cam with oscillating follower.展开更多
In this paper,wavefield storage optimization strategies are discussed with respect to reverse-time migration(RTM)imaging in reflection-acoustic logging,considering the problem of massive wavefield data storage in RTM ...In this paper,wavefield storage optimization strategies are discussed with respect to reverse-time migration(RTM)imaging in reflection-acoustic logging,considering the problem of massive wavefield data storage in RTM itself.In doing so,two optimization methods are proposed and implemented to avoid wavefield storage.Firstly,the RTM based on the excitation-amplitude imaging condition uses the excitation time to judge the imaging time,and accordingly,we only need to store a small part of wavefield,such as the wavefield data of dozens of time points,the instances prove that they can even be imaged by only two time points.The traditional RTM usually needs to store the wavefield data of thousands of time points,compared with which the data storage can be reduced by tens or even thousands of times.Secondly,the RTM based on the random boundary uses the idea that the wavefield scatters rather than reflects in a random medium to reconstruct the wavefield source and thereby directly avoid storing the forward wavefield data.Numerical examples show that compared with other migration algorithms and the traditional RTM,both methods can effectively reduce wavefield data storage as well as improve data-processing efficiency while ensuring imaging accuracy,thereby providing the means for high-efficiency and highprecision imaging of fractures and caves by boreholes.展开更多
Background It is debatable whether treating multimorbid nursing home patients with antihypertensive drugs produces beneficial effects. Most cardiovascular guidelines promote treatment; few have advice on how to depres...Background It is debatable whether treating multimorbid nursing home patients with antihypertensive drugs produces beneficial effects. Most cardiovascular guidelines promote treatment; few have advice on how to deprescribe when treatment may no longer be necessary. We investigated the effect of medication review on antihypertensive drug use and the association between cognition, blood pressure, and prescribing. Methods From August 2014 to December 2015, 765 patients from 72 units (clusters) in 32 Norwegian nursing homes were included in a 4-month, multicentre, cluster-randomized, controlled trial, with 9-month follow-up. Patients ≥ 65 years old with antihypertensive treatment (n = 295, 39%) were randomized to systematic medication review where the physician received support from peers (collegial mentoring) or were given care as usual (control condition). Outcome measures were the number of antihypertensive drugs, systolic blood pressure, and pulse. We used hospitalizations and deaths as criteria to assess harm. Results At baseline, each patient used 9.2 ± 3.5 regular drugs, and 1.6 ± 0.7 antihypertensives. Mean blood pressure was 128/71 mmHg and 9% had a systolic pressure ≥ 160 mmHg. Between baseline and month four, antihypertensives were deprescribed to a significantly higher extent in the intervention group (n = 43, 32%) compared to control (n = 11, 10%); Incidence Rate Ratio = 0.8, 95% CI = 0.7?0.9. In the intervention group, there was an immediate increase in systolic blood pressure when antihypertensives were reduced, from baseline 128 ± 19.5 mmHg to 143 ± 25.5 mmHg at month four. However, at month nine, the blood pressure had reverted to baseline values (mean 134 mmHg). Deprescription did not affect pulse and systolic pressure. The number of hospitalizations was higher in control patients at month four (P = 0.031) and nine (P = 0.041). Conclusion A systematic medication review supported by collegial mentoring significantly decreased the use of antihypertensive drugs in nursing home patients without an effect on the systolic blood pressure over time.展开更多
Seismic sedimentology is the study of sedimentary rocks and facies using seismic data. However, often the sedimentary body features can't be described quantitatively due to the limit of seismic resolution. High resol...Seismic sedimentology is the study of sedimentary rocks and facies using seismic data. However, often the sedimentary body features can't be described quantitatively due to the limit of seismic resolution. High resolution inversion offsets this limitation and is applied to seismic sedimentology to identify subtle traps under complex geologic conditions, thereby widening the applicable range of seismic sedimentology. In this paper, based on seismic sedimentology, seismic phase-controlled nonlinear random inversion is used to predict the sandy conglomerate reservoir of Es3 in the Chezhen depression in Shengli Oilfield. Thickness and sedimentary microfacies maps of sandy conglomerate bodies in several stages are presented and several subtle traps were predicted and verified by drilling.展开更多
Video object segmentation is important for video surveillance, object tracking, video object recognition and video editing. An adaptive video segmentation algorithm based on hidden conditional random fields (HCRFs) is...Video object segmentation is important for video surveillance, object tracking, video object recognition and video editing. An adaptive video segmentation algorithm based on hidden conditional random fields (HCRFs) is proposed, which models spatio-temporal constraints of video sequence. In order to improve the segmentation quality, the weights of spatio-temporal con- straints are adaptively updated by on-line learning for HCRFs. Shadows are the factors affecting segmentation quality. To separate foreground objects from the shadows they cast, linear transform for Gaussian distribution of the background is adopted to model the shadow. The experimental results demonstrated that the error ratio of our algorithm is reduced by 23% and 19% respectively, compared with the Gaussian mixture model (GMM) and spatio-temporal Markov random fields (MRFs).展开更多
Split Hopkinson pressure bar(SHPB) apparatus, usually used for testing behavior of material in median and high strain-rate, is now widely used in the study of rock dynamic constitutive relation, damage evolvement me...Split Hopkinson pressure bar(SHPB) apparatus, usually used for testing behavior of material in median and high strain-rate, is now widely used in the study of rock dynamic constitutive relation, damage evolvement mechanism and energy consumption. However, the possible reasons of sampling disturbance, machining error and so on often lead to the scattering of test results, and bring ultimate difficulty for forming general test conclusion. Based on the stochastic finite element method, the uncertain parameters of specimen density ps, specimen radius Rs, specimen elastic modulus Es and specimen length Ls in the data processing of SHPB test were considered, and the correlation between the parameters and the test results was analyzed. The results show that the specimen radius Rs has direct correlation with the test result, improving the accuracy in preparing and measuring of specimen is an effective way to improve the accuracy of test and minish the scattering of results for SHPB test.展开更多
In order to study whether the random events set can be used in Rudongbank of Nantong or not, we use ADCIRC model to stimulate the storm surge affectingRudong bank based on random events set. Then we use p-III curve to...In order to study whether the random events set can be used in Rudongbank of Nantong or not, we use ADCIRC model to stimulate the storm surge affectingRudong bank based on random events set. Then we use p-III curve to fit peak-value ofsurge of all the years to get the surge of typical return periods. The result shows that theresults of fitting by ADCIRC and by historical data coincide well in lower return periods,but to higher return periods, the results of fitting by ADCIRC are significantly higher thanthat of fitting by historical data. Due to the short time, it’s not enough for the extremestorm surge events to occur, the results of higher return periods are not reliable, so wecan’t rule out the reasonability of results based on random events set. The results offitting based on random events set are accurate in lower return periods and we can alsofully estimate the surge of higher return periods based on random events set. In thesituation of lacking historical data of hundreds of years, random events set can beaccepted as a tool to compute the return period of storm surge. Consideration of globalwarming, the possibility of super typhoons’ appearance will rise, which will result inhigher surge of return periods. In order to prevent the disaster of storm surge, thegovernment needs to deepen and reinforce the coastal engineering like seawalls and embankments.展开更多
Objectives:to verify the feasibility and reliability of the electronic version of Chinese SF-36 based on the Quality-of-Life-Recorder. Design: A crossover randomized controlled trial, comparing a paper-based and an el...Objectives:to verify the feasibility and reliability of the electronic version of Chinese SF-36 based on the Quality-of-Life-Recorder. Design: A crossover randomized controlled trial, comparing a paper-based and an electronic version of the Chinese SF-36, was conducted. According to generated random numbers, interviewees were asked to fill out either the electronic version or the paper version first. The second version was filled in after a pause of at least 10 min. Settings and participants: One group of 100 medical students at the School of Medicine of Zhejiang University and the other group of 50 outpatients at a clinic for general practice in Hangzhou City (China) were eventually recruited in this study. Results: The acceptance of the electronic version was good (60% of medical students and 84% of outpatients preferred the electronic version). At the level of eight-scale scores, the mean-difference for each scale (except for general health) between the two versions was less than 5%. At the level of 36 questions, the percentage of "exact agreement" ranged within 64%~99%; the percentage of "global agreement" ranged within 72%~99%; 77% of the kappa coefficients demonstrated "good/excellent agreement" and 23% of the kappa coefficients demonstrated "medium agreement". Conclusion: This study, for the first time, can provide empirical basis for the confirmation of the feasibility and reliability of the electronic version of the Chinese SF-36 and may provide an impulse towards widespread deployment of the Quality-of-Life-Recorder in Chinese populations.展开更多
AIM:To investigate health-related quality of life(HRQoL) and psychological outcomes in 256 adults who had undergone liver transplantation(LT).METHODS:A stratified random sampling method was used in this follow-up mult...AIM:To investigate health-related quality of life(HRQoL) and psychological outcomes in 256 adults who had undergone liver transplantation(LT).METHODS:A stratified random sampling method was used in this follow-up multicenter study to select a representative sample of recipients undergoing either living donor liver transplantation(LDLT) or deceased donor liver transplantation(DDLT).HRQoL was measured by using the Chinese version of Medical Outcome Study Short Form-36(SF-36),and psychological outcomes by using the beck anxiety inventory(BAI) and the self-rating depression scale(SDS).Clinical and demographic data were collected from the records of the Chinese Liver Transplant Registry and via questionnaires.RESULTS:A total of 256 patients were sampled,including 66(25.8%) receiving LDLT and 190(74.2%) undergoing DDLT;15(5.9%) recipients had anxiety and four(1.6%) developed severe depression after the operation.Compared with LDLT recipients,DDLT patients had higher scores in general health(60.33 ± 16.97 vs 66.86 ± 18.42,P = 0.012),role-physical(63.64 ± 42.55 vs 74.47 ± 36.46,P = 0.048),roleemotional(61.11 ± 44.37 vs 78.95 ± 34.31,P = 0.001),social functioning(78.60 ± 22.76 vs 88.16 ± 21.85,P = 0.003),vitality(70.30 ± 15.76 vs 75.95 ± 16.40,P = 0.016),mental health(65.88 ± 12.94 vs 71.85 ± 15.45,P = 0.005),physical component summary scale(PCS,60.07 ± 7.36 vs 62.58 ± 6.88,P = 0.013) and mental component summary scale(MCS,52.65 ± 7.66 vs 55.95 ± 10.14,P = 0.016).Recipients > 45 years old at the time of transplant scored higher in vitality(77.33 ± 15.64 vs 72.52 ± 16.66,P = 0.020),mental health(73.64 ± 15.06 vs 68.00 ± 14.65,P = 0.003) and MCS(56.61 ± 10.00 vs 54.05 ± 9.30,P = 0.037) than those aged ≤ 45 years.MCS was poorer in recipients with than in those without complications(52.92 ± 12.21 vs 56.06 ± 8.16,P = 0.017).Regarding MCS(55.10 ± 9.66 vs 50.0 ± 10.0,P < 0.05) and PCS(61.93 ± 7.08 vs 50.0 ± 10.0,P < 0.05),recipients scored better than the Sichuan general and had improved overall QoL compared to patients with chronic diseases.MCS and PCS significantly correlated with scores of the BAI(P < 0.001) and the SDS(P < 0.001).CONCLUSION:Age > 45 years at time of transplant,DDLT,full-time working,no complications,anxiety and depression were possible factors influencing postoperative HRQoL in liver recipients.展开更多
Based on variable sized chunking, this paper proposes a content aware chunking scheme, called CAC, that does not assume fully random file contents, but tonsiders the characteristics of the file types. CAC uses a candi...Based on variable sized chunking, this paper proposes a content aware chunking scheme, called CAC, that does not assume fully random file contents, but tonsiders the characteristics of the file types. CAC uses a candidate anchor histogram and the file-type specific knowledge to refine how anchors are determined when performing de- duplication of file data and enforces the selected average chunk size. CAC yields more chunks being found which in turn produces smaller average chtmks and a better reduction in data. We present a detailed evaluation of CAC and the experimental results show that this scheme can improve the compression ratio chunking for file types whose bytes are not randomly distributed (from 11.3% to 16.7% according to different datasets), and improve the write throughput on average by 9.7%.展开更多
This paper presents software reliability modeling issues at the early stage of a software development for fault tolerant software management system. Based on Stochastic Reward Nets, an effective model of hierarchical ...This paper presents software reliability modeling issues at the early stage of a software development for fault tolerant software management system. Based on Stochastic Reward Nets, an effective model of hierarchical view for a fault tolerant software management system is put forward, and an approach that consists of system transient performance analysis is adopted. A quantitative approach for software reliability analysis is given. The results show its usefulness for the design and evaluation of the early-stage software reliability modeling when failure data is not available.展开更多
To provide services in presence of failures or attacks in a timely manner, the network survivability was analyzed. Based on stochastic Petri nets, we put forward an effective model for ad hoe network and adopt a two-p...To provide services in presence of failures or attacks in a timely manner, the network survivability was analyzed. Based on stochastic Petri nets, we put forward an effective model for ad hoe network and adopt a two-phase approach consisting of the steady-state availability analysis and the system transient performance analysis, then provide a quantitative approach for analysis of the network survivability. The results show that the proposed model is useful for the design and evaluation of the wireless ad hoc network.展开更多
基金The National Natural Science Foundation of China(No60663004)the PhD Programs Foundation of Ministry of Educa-tion of China (No20050007023)
文摘Due to the fact that semantic role labeling (SRL) is very necessary for deep natural language processing, a method based on conditional random fields (CRFs) is proposed for the SRL task. This method takes shallow syntactic parsing as the foundation, phrases or named entities as the labeled units, and the CRFs model is trained to label the predicates' semantic roles in a sentence. The key of the method is parameter estimation and feature selection for the CRFs model. The L-BFGS algorithm was employed for parameter estimation, and three category features: features based on sentence constituents, features based on predicate, and predicate-constituent features as a set of features for the model were selected. Evaluation on the datasets of CoNLL-2005 SRL shared task shows that the method can obtain better performance than the maximum entropy model, and can achieve 80. 43 % precision and 63. 55 % recall for semantic role labeling.
文摘The use of hidden conditional random fields (HCRFs) for tone modeling is explored. The tone recognition performance is improved using HCRFs by taking advantage of intra-syllable dynamic, inter-syllable dynamic and duration features. When the tone model is integrated into continuous speech recognition, the discriminative model weight training (DMWT) is proposed. Acoustic and tone scores are scaled by model weights discriminatively trained by the minimum phone error (MPE) criterion. Two schemes of weight training are evaluated and a smoothing technique is used to make training robust to overtraining problem. Experiments show that the accuracies of tone recognition and large vocabulary continuous speech recognition (LVCSR) can be improved by the HCRFs based tone model. Compared with the global weight scheme, continuous speech recognition can be improved by the discriminative trained weight combinations.
基金The National High Technology Research and Development Program of China(863 Program)(No.2012AA112304)the Scientific Innovation Research of College Graduates in Jiangsu Province(No.CXZZ13-0119)
文摘In order to avoid the noise and over fitting and further improve the limited classification performance of the real decision tree, a traffic incident detection method based on the random forest algorithm is presented. From the perspective of classification strength and correlation, three experiments are performed to investigate the potential application of random forest to traffic incident detection: comparison with a different number of decision trees; comparison with different decision trees; comparison with the neural network. The real traffic data of the 1-880 database is used in the experiments. The detection performance is evaluated by the common criteria including the detection rate, the false alarm rate, the mean time to detection, the classification rate and the area under the curve of the receiver operating characteristic (ROC). The experimental results indicate that the model based on random forest can improve the decision rate, reduce the testing time, and obtain a higher classification rate. Meanwhile, it is competitive compared with multi-layer feed forward neural networks (MLF).
文摘Let X (t)(t∈R^N) be a d-dimensional fractional Brownian motion. A contiunous function f:R^N→R^d is called a polar function of X(t)(t∈R^N) if P{ t∈R^N\{0},X(t)=t(t)}=0. In this paper, the characteristies of the class of polar functions are studied. Our theorem 1 improves the previous results of Graversen and Legall. Theorem2 solves a problem of Legall (1987) on Brownian motion.
基金Project supported by the National Natural Science Foundation of China (No. 50575205)the HiTech Research and Development Program (863) of China (No. 2006AA04Z233)and the Natural Science Foundation of Zhejiang Province (Nos. Y104243 and Y105686), China
文摘This paper focuses on the analysis of running conditions and machining processes of conical cam with oscillating follower. We point out the common errors existing in the design and machining of the widely used plane expansion method of conical cam trough-out line. We show that the motion can be divided into two parts, i.e. the oscillating motion of oscillating bar and the rotary motion of oscillating bar relative to the conical cam. By increasing the rotary motion of oscillating bar, the motion path of tapered roller on oscillating bar (i.e. contour surface of conical cam) can be expanded on the cylinder. Based on these analyses, we present a creative and effective designing and machining method for 3D curve expansion of conical cam with oscillating follower.
基金supported by CNPC scientific research and technology development projects(No.2016A-3605)
文摘In this paper,wavefield storage optimization strategies are discussed with respect to reverse-time migration(RTM)imaging in reflection-acoustic logging,considering the problem of massive wavefield data storage in RTM itself.In doing so,two optimization methods are proposed and implemented to avoid wavefield storage.Firstly,the RTM based on the excitation-amplitude imaging condition uses the excitation time to judge the imaging time,and accordingly,we only need to store a small part of wavefield,such as the wavefield data of dozens of time points,the instances prove that they can even be imaged by only two time points.The traditional RTM usually needs to store the wavefield data of thousands of time points,compared with which the data storage can be reduced by tens or even thousands of times.Secondly,the RTM based on the random boundary uses the idea that the wavefield scatters rather than reflects in a random medium to reconstruct the wavefield source and thereby directly avoid storing the forward wavefield data.Numerical examples show that compared with other migration algorithms and the traditional RTM,both methods can effectively reduce wavefield data storage as well as improve data-processing efficiency while ensuring imaging accuracy,thereby providing the means for high-efficiency and highprecision imaging of fractures and caves by boreholes.
文摘Background It is debatable whether treating multimorbid nursing home patients with antihypertensive drugs produces beneficial effects. Most cardiovascular guidelines promote treatment; few have advice on how to deprescribe when treatment may no longer be necessary. We investigated the effect of medication review on antihypertensive drug use and the association between cognition, blood pressure, and prescribing. Methods From August 2014 to December 2015, 765 patients from 72 units (clusters) in 32 Norwegian nursing homes were included in a 4-month, multicentre, cluster-randomized, controlled trial, with 9-month follow-up. Patients ≥ 65 years old with antihypertensive treatment (n = 295, 39%) were randomized to systematic medication review where the physician received support from peers (collegial mentoring) or were given care as usual (control condition). Outcome measures were the number of antihypertensive drugs, systolic blood pressure, and pulse. We used hospitalizations and deaths as criteria to assess harm. Results At baseline, each patient used 9.2 ± 3.5 regular drugs, and 1.6 ± 0.7 antihypertensives. Mean blood pressure was 128/71 mmHg and 9% had a systolic pressure ≥ 160 mmHg. Between baseline and month four, antihypertensives were deprescribed to a significantly higher extent in the intervention group (n = 43, 32%) compared to control (n = 11, 10%); Incidence Rate Ratio = 0.8, 95% CI = 0.7?0.9. In the intervention group, there was an immediate increase in systolic blood pressure when antihypertensives were reduced, from baseline 128 ± 19.5 mmHg to 143 ± 25.5 mmHg at month four. However, at month nine, the blood pressure had reverted to baseline values (mean 134 mmHg). Deprescription did not affect pulse and systolic pressure. The number of hospitalizations was higher in control patients at month four (P = 0.031) and nine (P = 0.041). Conclusion A systematic medication review supported by collegial mentoring significantly decreased the use of antihypertensive drugs in nursing home patients without an effect on the systolic blood pressure over time.
基金sponsored by the 973 Program(Grant No.2006CB202306)Open Fund of the State Key Laboratory of Petroleum Resource and Prospecting(Grant No.PRPDX2008-07)
文摘Seismic sedimentology is the study of sedimentary rocks and facies using seismic data. However, often the sedimentary body features can't be described quantitatively due to the limit of seismic resolution. High resolution inversion offsets this limitation and is applied to seismic sedimentology to identify subtle traps under complex geologic conditions, thereby widening the applicable range of seismic sedimentology. In this paper, based on seismic sedimentology, seismic phase-controlled nonlinear random inversion is used to predict the sandy conglomerate reservoir of Es3 in the Chezhen depression in Shengli Oilfield. Thickness and sedimentary microfacies maps of sandy conglomerate bodies in several stages are presented and several subtle traps were predicted and verified by drilling.
基金Project supported by the National Natural Science Foundation of China (Nos. 60473106, 60273060 and 60333010)the Ministry of Education of China (No. 20030335064)the Education Depart-ment of Zhejiang Province, China (No. G20030433)
文摘Video object segmentation is important for video surveillance, object tracking, video object recognition and video editing. An adaptive video segmentation algorithm based on hidden conditional random fields (HCRFs) is proposed, which models spatio-temporal constraints of video sequence. In order to improve the segmentation quality, the weights of spatio-temporal con- straints are adaptively updated by on-line learning for HCRFs. Shadows are the factors affecting segmentation quality. To separate foreground objects from the shadows they cast, linear transform for Gaussian distribution of the background is adopted to model the shadow. The experimental results demonstrated that the error ratio of our algorithm is reduced by 23% and 19% respectively, compared with the Gaussian mixture model (GMM) and spatio-temporal Markov random fields (MRFs).
基金Projects(50490274, 50534030) supported by the National Natural Science Foundation of ChinaProject supported by the Natural Science Foundatin of Hunan Province, China
文摘Split Hopkinson pressure bar(SHPB) apparatus, usually used for testing behavior of material in median and high strain-rate, is now widely used in the study of rock dynamic constitutive relation, damage evolvement mechanism and energy consumption. However, the possible reasons of sampling disturbance, machining error and so on often lead to the scattering of test results, and bring ultimate difficulty for forming general test conclusion. Based on the stochastic finite element method, the uncertain parameters of specimen density ps, specimen radius Rs, specimen elastic modulus Es and specimen length Ls in the data processing of SHPB test were considered, and the correlation between the parameters and the test results was analyzed. The results show that the specimen radius Rs has direct correlation with the test result, improving the accuracy in preparing and measuring of specimen is an effective way to improve the accuracy of test and minish the scattering of results for SHPB test.
文摘In order to study whether the random events set can be used in Rudongbank of Nantong or not, we use ADCIRC model to stimulate the storm surge affectingRudong bank based on random events set. Then we use p-III curve to fit peak-value ofsurge of all the years to get the surge of typical return periods. The result shows that theresults of fitting by ADCIRC and by historical data coincide well in lower return periods,but to higher return periods, the results of fitting by ADCIRC are significantly higher thanthat of fitting by historical data. Due to the short time, it’s not enough for the extremestorm surge events to occur, the results of higher return periods are not reliable, so wecan’t rule out the reasonability of results based on random events set. The results offitting based on random events set are accurate in lower return periods and we can alsofully estimate the surge of higher return periods based on random events set. In thesituation of lacking historical data of hundreds of years, random events set can beaccepted as a tool to compute the return period of storm surge. Consideration of globalwarming, the possibility of super typhoons’ appearance will rise, which will result inhigher surge of return periods. In order to prevent the disaster of storm surge, thegovernment needs to deepen and reinforce the coastal engineering like seawalls and embankments.
基金Project (No. WKJ2006-2-016) supported by the project of "Effect of Chronic Disease and Health-Related Quality of Life on Health Service Utilization" from the Ministry of Health, China
文摘Objectives:to verify the feasibility and reliability of the electronic version of Chinese SF-36 based on the Quality-of-Life-Recorder. Design: A crossover randomized controlled trial, comparing a paper-based and an electronic version of the Chinese SF-36, was conducted. According to generated random numbers, interviewees were asked to fill out either the electronic version or the paper version first. The second version was filled in after a pause of at least 10 min. Settings and participants: One group of 100 medical students at the School of Medicine of Zhejiang University and the other group of 50 outpatients at a clinic for general practice in Hangzhou City (China) were eventually recruited in this study. Results: The acceptance of the electronic version was good (60% of medical students and 84% of outpatients preferred the electronic version). At the level of eight-scale scores, the mean-difference for each scale (except for general health) between the two versions was less than 5%. At the level of 36 questions, the percentage of "exact agreement" ranged within 64%~99%; the percentage of "global agreement" ranged within 72%~99%; 77% of the kappa coefficients demonstrated "good/excellent agreement" and 23% of the kappa coefficients demonstrated "medium agreement". Conclusion: This study, for the first time, can provide empirical basis for the confirmation of the feasibility and reliability of the electronic version of the Chinese SF-36 and may provide an impulse towards widespread deployment of the Quality-of-Life-Recorder in Chinese populations.
基金Supported by A grant from the National Science and Technology Major Project of China,No.2008ZX10002-025, 2008ZX10002-026
文摘AIM:To investigate health-related quality of life(HRQoL) and psychological outcomes in 256 adults who had undergone liver transplantation(LT).METHODS:A stratified random sampling method was used in this follow-up multicenter study to select a representative sample of recipients undergoing either living donor liver transplantation(LDLT) or deceased donor liver transplantation(DDLT).HRQoL was measured by using the Chinese version of Medical Outcome Study Short Form-36(SF-36),and psychological outcomes by using the beck anxiety inventory(BAI) and the self-rating depression scale(SDS).Clinical and demographic data were collected from the records of the Chinese Liver Transplant Registry and via questionnaires.RESULTS:A total of 256 patients were sampled,including 66(25.8%) receiving LDLT and 190(74.2%) undergoing DDLT;15(5.9%) recipients had anxiety and four(1.6%) developed severe depression after the operation.Compared with LDLT recipients,DDLT patients had higher scores in general health(60.33 ± 16.97 vs 66.86 ± 18.42,P = 0.012),role-physical(63.64 ± 42.55 vs 74.47 ± 36.46,P = 0.048),roleemotional(61.11 ± 44.37 vs 78.95 ± 34.31,P = 0.001),social functioning(78.60 ± 22.76 vs 88.16 ± 21.85,P = 0.003),vitality(70.30 ± 15.76 vs 75.95 ± 16.40,P = 0.016),mental health(65.88 ± 12.94 vs 71.85 ± 15.45,P = 0.005),physical component summary scale(PCS,60.07 ± 7.36 vs 62.58 ± 6.88,P = 0.013) and mental component summary scale(MCS,52.65 ± 7.66 vs 55.95 ± 10.14,P = 0.016).Recipients > 45 years old at the time of transplant scored higher in vitality(77.33 ± 15.64 vs 72.52 ± 16.66,P = 0.020),mental health(73.64 ± 15.06 vs 68.00 ± 14.65,P = 0.003) and MCS(56.61 ± 10.00 vs 54.05 ± 9.30,P = 0.037) than those aged ≤ 45 years.MCS was poorer in recipients with than in those without complications(52.92 ± 12.21 vs 56.06 ± 8.16,P = 0.017).Regarding MCS(55.10 ± 9.66 vs 50.0 ± 10.0,P < 0.05) and PCS(61.93 ± 7.08 vs 50.0 ± 10.0,P < 0.05),recipients scored better than the Sichuan general and had improved overall QoL compared to patients with chronic diseases.MCS and PCS significantly correlated with scores of the BAI(P < 0.001) and the SDS(P < 0.001).CONCLUSION:Age > 45 years at time of transplant,DDLT,full-time working,no complications,anxiety and depression were possible factors influencing postoperative HRQoL in liver recipients.
基金Supported by the National Natural Science Foundation of China (No.60673001) the State Key Development Program of Basic Research of China (No. 2004CB318203).
文摘Based on variable sized chunking, this paper proposes a content aware chunking scheme, called CAC, that does not assume fully random file contents, but tonsiders the characteristics of the file types. CAC uses a candidate anchor histogram and the file-type specific knowledge to refine how anchors are determined when performing de- duplication of file data and enforces the selected average chunk size. CAC yields more chunks being found which in turn produces smaller average chtmks and a better reduction in data. We present a detailed evaluation of CAC and the experimental results show that this scheme can improve the compression ratio chunking for file types whose bytes are not randomly distributed (from 11.3% to 16.7% according to different datasets), and improve the write throughput on average by 9.7%.
基金This work was supported in part by the Ph.D.Programs Foundation of Ministry of Education of China under
文摘This paper presents software reliability modeling issues at the early stage of a software development for fault tolerant software management system. Based on Stochastic Reward Nets, an effective model of hierarchical view for a fault tolerant software management system is put forward, and an approach that consists of system transient performance analysis is adopted. A quantitative approach for software reliability analysis is given. The results show its usefulness for the design and evaluation of the early-stage software reliability modeling when failure data is not available.
基金the PhD Programs Foundation for Young Researchers of Ministry of Education of China(Grant No.20070217051)the National High Technology Research and Development Program of China(Grant No.2007AA01Z491)
文摘To provide services in presence of failures or attacks in a timely manner, the network survivability was analyzed. Based on stochastic Petri nets, we put forward an effective model for ad hoe network and adopt a two-phase approach consisting of the steady-state availability analysis and the system transient performance analysis, then provide a quantitative approach for analysis of the network survivability. The results show that the proposed model is useful for the design and evaluation of the wireless ad hoc network.