Traditional packet classification for IPv4 involves examining standard 5-tuple of a packet header,source address,destination address,source port,destination port and protocol.With introduction of IPv6 flow label field...Traditional packet classification for IPv4 involves examining standard 5-tuple of a packet header,source address,destination address,source port,destination port and protocol.With introduction of IPv6 flow label field which entails labeling the packets belonging to the same flow,packet classification can be resolved based on 3 dimensions:flow label,source address and destination address.In this paper,we propose a novel approach for the 3-tuple packet classification based on flow label.Besides,by introducing a conversion engine to covert the source-destination pairs to the compound address prefixes,we put forward an algorithm called Reducing Dimension(RD) with dimension reduction capability,which combines heuristic tree search with usage of buckets.And we also provide an improved version of RD,called Improved RD(IRD),which uses two mechanisms:path compression and priority tag,to optimize the performance.To evaluate our algorithm,extensive experiments have been conducted using a number of synthetically generated databases.For the memory consumption,the two proposed new algorithms only consumes around 3% of the existing algorithms when the number of filters increases to 10 k.And for the average search time,the search time of the two proposed algorithms is more than four times faster than others when the number of filters is 10 k.The results show that the proposed algorithm works well and outperforms many typical existing algorithms with the dimension reduction capability.展开更多
Cerebral blood flow is strongly associated with brain function, and is the main symptom and diagnostic basis for a variety of encephalopathies. However, changes in cerebral blood flow after mild traumatic brain injury...Cerebral blood flow is strongly associated with brain function, and is the main symptom and diagnostic basis for a variety of encephalopathies. However, changes in cerebral blood flow after mild traumatic brain injury remain poorly understood. This study sought to observe changes in cerebral blood flow in different regions after mild traumatic brain injury using pulsed arterial spin labeling. Our results demonstrate maximal cerebral blood flow in gray matter and minimal in the white matter of patients with mild traumatic brain injury. At the acute and subacute stages, cerebral blood flow was reduced in the occipital lobe, parietal lobe, central region, subcutaneous region, and frontal lobe. Cerebral blood flow was restored at the chronic stage. At the acute, subacute, and chronic stages, changes in cerebral blood flow were not apparent in the insula. Cerebral blood flow in the temporal lobe and limbic lobe diminished at the acute and subacute stages, but was restored at the chronic stage. These findings suggest that pulsed arterial spin labeling can precisely measure cerebral blood flow in various brain regions, and may play a reference role in evaluating a patient＇s condition and judging prognosis after traumatic brain injury.展开更多
Optical flow method is one of the most important methods of analyzing motion images. Optical flow field is used to analyze characteristics of motion objects. According to motion features of micro-electronic mechani-ca...Optical flow method is one of the most important methods of analyzing motion images. Optical flow field is used to analyze characteristics of motion objects. According to motion features of micro-electronic mechani-cal system (MEMS) micro-structure, the optical algorithm based on label field and neighborhood optimization is presented to analyze the in-plane micro-motion of micro-structure. Firstly, high speed motion states for each fre-quency segment of micro-structure in cyclic motion are frozen based on stroboscopic principle. Thus a series of dynamic images of micro-structure are obtained. Secondly, the presented optical algorithm is used to analyze the image sequences, and can obtain reliable and precise optical field and reduce computing time. As micro-resonator of testing object, the phase-amplitude curve of micro-structure is derived. Experimental results indicate that the meas-urement precision of the presented algorithm is high, and measurement repeatability reaches 40 nm under the same experiment condition.展开更多
AIM: To assess whether non invasive blood flow measurement by arterial spin labeling in several brain regions detects minimal hepatic encephalopathy. METHODS: Blood flow(BF) was analyzed by arterial spin labeling(ASL)...AIM: To assess whether non invasive blood flow measurement by arterial spin labeling in several brain regions detects minimal hepatic encephalopathy. METHODS: Blood flow(BF) was analyzed by arterial spin labeling(ASL) in different brain areas of 14 controls, 24 cirrhotic patients without and 16 cirrhotic patients with minimal hepatic encephalopathy(MHE). Images were collected using a 3 Tesla MR scanner(Achieva 3T-TX, Philips, Netherlands). Pulsed ASL was performed. Patients showing MHE were detected using the battery Psychometric Hepatic Encephalopathy Score(PHES) consisting of five tests. Different cognitive and motor functions were also assessed: alterations in selective attention were evaluated using the Stroop test. Patients and controls also performed visuo-motor and bimanual coordination tests. Several biochemical parameters were measured: serum pro-inflammatory interleukins(IL-6 and IL-18), 3-nitrotyrosine, cGMP and nitrates+nitrites in plasma, and blood ammonia. Bivariate correlations were evaluated.RESULTS: In patients with MHE, BF was increased in cerebellar hemisphere(P = 0.03) and vermis(P = 0.012) and reduced in occipital lobe(P = 0.017). BF in cerebellar hemisphere was also increased in patients without MHE(P = 0.02). Bimanual coordination was impaired in patients without MHE(P = 0.05) and much more in patients with MHE(P < 0.0001). Visuo-motor coordination was impaired only in patients with MHE(P < 0.0001). Attention was slightly affected in patients without MHE and more strongly in patients with MHE(P< 0.0001). BF in cerebellar hemisphere and vermis correlated with performance in most tests of PHES [(number connection tests A(NCT-A), B(NCT-B)and line tracing test] and in the congruent task of Stroop test. BF in frontal lobe correlated with NCT-A. Performance in bimanual and visuomotor coordination tests correlated only with BF in cerebellar hemisphere. BF in occipital lobe correlates with performance in the PHES battery and with CFF. BF in cerebellar hemisphere correlates with plasma cGMP and nitric oxide(NO) metabolites. BF in vermis cerebellar also correlates with NO metabolites and with 3-nitrotyrosine. IL-18 in plasma correlates with BF in thalamus and occipital lobe.CONCLUSION: Non invasive BF determination in cerebellum using ASL may detect MHE earlier than the PHES. Altered NO-cGMP pathway seems to be associated to altered BF in cerebellum.展开更多
基金This paper was supported by the National Natural Science Foundation of China under Crant No. 61003282 the Funda- mental Research Funds for the Central Universities under Crant No. 2011RCI）508+1 种基金 National Basic Research Program of China under Crant No. 2009CB320505 National High Technol-ogy Research and Development Program of China under Oant No. 2011AA010704.
文摘Traditional packet classification for IPv4 involves examining standard 5-tuple of a packet header,source address,destination address,source port,destination port and protocol.With introduction of IPv6 flow label field which entails labeling the packets belonging to the same flow,packet classification can be resolved based on 3 dimensions:flow label,source address and destination address.In this paper,we propose a novel approach for the 3-tuple packet classification based on flow label.Besides,by introducing a conversion engine to covert the source-destination pairs to the compound address prefixes,we put forward an algorithm called Reducing Dimension(RD) with dimension reduction capability,which combines heuristic tree search with usage of buckets.And we also provide an improved version of RD,called Improved RD(IRD),which uses two mechanisms:path compression and priority tag,to optimize the performance.To evaluate our algorithm,extensive experiments have been conducted using a number of synthetically generated databases.For the memory consumption,the two proposed new algorithms only consumes around 3% of the existing algorithms when the number of filters increases to 10 k.And for the average search time,the search time of the two proposed algorithms is more than four times faster than others when the number of filters is 10 k.The results show that the proposed algorithm works well and outperforms many typical existing algorithms with the dimension reduction capability.
文摘Cerebral blood flow is strongly associated with brain function, and is the main symptom and diagnostic basis for a variety of encephalopathies. However, changes in cerebral blood flow after mild traumatic brain injury remain poorly understood. This study sought to observe changes in cerebral blood flow in different regions after mild traumatic brain injury using pulsed arterial spin labeling. Our results demonstrate maximal cerebral blood flow in gray matter and minimal in the white matter of patients with mild traumatic brain injury. At the acute and subacute stages, cerebral blood flow was reduced in the occipital lobe, parietal lobe, central region, subcutaneous region, and frontal lobe. Cerebral blood flow was restored at the chronic stage. At the acute, subacute, and chronic stages, changes in cerebral blood flow were not apparent in the insula. Cerebral blood flow in the temporal lobe and limbic lobe diminished at the acute and subacute stages, but was restored at the chronic stage. These findings suggest that pulsed arterial spin labeling can precisely measure cerebral blood flow in various brain regions, and may play a reference role in evaluating a patient＇s condition and judging prognosis after traumatic brain injury.
基金Supported by Youth Natural Science Foundation of Beijing University of Chemical Technology (No.QN0734).
文摘Optical flow method is one of the most important methods of analyzing motion images. Optical flow field is used to analyze characteristics of motion objects. According to motion features of micro-electronic mechani-cal system (MEMS) micro-structure, the optical algorithm based on label field and neighborhood optimization is presented to analyze the in-plane micro-motion of micro-structure. Firstly, high speed motion states for each fre-quency segment of micro-structure in cyclic motion are frozen based on stroboscopic principle. Thus a series of dynamic images of micro-structure are obtained. Secondly, the presented optical algorithm is used to analyze the image sequences, and can obtain reliable and precise optical field and reduce computing time. As micro-resonator of testing object, the phase-amplitude curve of micro-structure is derived. Experimental results indicate that the meas-urement precision of the presented algorithm is high, and measurement repeatability reaches 40 nm under the same experiment condition.
基金Supported by Ministerio de Ciencia e Innovación,Nos.FIS PS09/00806FIS PI12/00884 to Montoliu C+3 种基金SAF2011-23051,CSD2008-00005 to Felipo VConsellería de Educación Generalitat Valenciana,Nos.PROMETEO-2009-027,ACOMP/2012/066 to Felipo V,No.ACOMP/2012/056 to Montoliu CSanitat,No.AP-004/11 to Felipo V,AP-087/11 to Montoliu CFundación ERESA to Montoliu C
文摘AIM: To assess whether non invasive blood flow measurement by arterial spin labeling in several brain regions detects minimal hepatic encephalopathy. METHODS: Blood flow(BF) was analyzed by arterial spin labeling(ASL) in different brain areas of 14 controls, 24 cirrhotic patients without and 16 cirrhotic patients with minimal hepatic encephalopathy(MHE). Images were collected using a 3 Tesla MR scanner(Achieva 3T-TX, Philips, Netherlands). Pulsed ASL was performed. Patients showing MHE were detected using the battery Psychometric Hepatic Encephalopathy Score(PHES) consisting of five tests. Different cognitive and motor functions were also assessed: alterations in selective attention were evaluated using the Stroop test. Patients and controls also performed visuo-motor and bimanual coordination tests. Several biochemical parameters were measured: serum pro-inflammatory interleukins(IL-6 and IL-18), 3-nitrotyrosine, cGMP and nitrates+nitrites in plasma, and blood ammonia. Bivariate correlations were evaluated.RESULTS: In patients with MHE, BF was increased in cerebellar hemisphere(P = 0.03) and vermis(P = 0.012) and reduced in occipital lobe(P = 0.017). BF in cerebellar hemisphere was also increased in patients without MHE(P = 0.02). Bimanual coordination was impaired in patients without MHE(P = 0.05) and much more in patients with MHE(P < 0.0001). Visuo-motor coordination was impaired only in patients with MHE(P < 0.0001). Attention was slightly affected in patients without MHE and more strongly in patients with MHE(P< 0.0001). BF in cerebellar hemisphere and vermis correlated with performance in most tests of PHES [(number connection tests A(NCT-A), B(NCT-B)and line tracing test] and in the congruent task of Stroop test. BF in frontal lobe correlated with NCT-A. Performance in bimanual and visuomotor coordination tests correlated only with BF in cerebellar hemisphere. BF in occipital lobe correlates with performance in the PHES battery and with CFF. BF in cerebellar hemisphere correlates with plasma cGMP and nitric oxide(NO) metabolites. BF in vermis cerebellar also correlates with NO metabolites and with 3-nitrotyrosine. IL-18 in plasma correlates with BF in thalamus and occipital lobe.CONCLUSION: Non invasive BF determination in cerebellum using ASL may detect MHE earlier than the PHES. Altered NO-cGMP pathway seems to be associated to altered BF in cerebellum.
