The dependence of elastic moduli of shales on the mineralogy and microstructure of shales is important for the prediction of sweet spots and shale gas production. Based on 3D digital images of the microstructure of Lo...The dependence of elastic moduli of shales on the mineralogy and microstructure of shales is important for the prediction of sweet spots and shale gas production. Based on 3D digital images of the microstructure of Longmaxi black shale samples using X-ray CT, we built detailed 3D digital images of cores with porosity properties and mineral contents. Next, we used finite-element （FE） methods to derive the elastic properties of the samples. The FE method can accurately model the shale mineralogy. Particular attention is paid to the derived elastic properties and their dependence on porosity and kerogen. The elastic moduli generally decrease with increasing porosity and kerogen, and there is a critical porosity （0.75） and kerogen content （ca. ≤3%） over which the elastic moduli decrease rapidly and slowly, respectively. The derived elastic moduli of gas- and oil-saturated digital cores differ little probably because of the low porosity （4.5%） of the Longmaxi black shale. Clearly, the numerical experiments demonstrated the feasibility of combining microstructure images of shale samples with elastic moduli calculations to predict shale properties.展开更多
The properties of the seismic geophones are important factors for high-resolution seismic exploration and have a great influence on data quality. For this reason, we have tested three kinds of geophones currently used...The properties of the seismic geophones are important factors for high-resolution seismic exploration and have a great influence on data quality. For this reason, we have tested three kinds of geophones currently used in several regions with different geological features： desert, saline-alkali farmland, and carbonate areas in mountainous regions in order to test their property indexes. Based on the geophone vibration equation and from the property index effects ofgeophone and the connection of the geophones on seismic data, we analyzed seismic data quality acquired inthe tested regions and suggest that suitable geophone property indexes, reasonable choice of geophone types, and the suitable geophone connection can enhance the signal/noise ratio of seismic data.展开更多
In the execution of method invocation sequences to test component security,abnormal or normal information is generated and recorded in a monitor log. By searching abnormal information from monitor log,the exceptions t...In the execution of method invocation sequences to test component security,abnormal or normal information is generated and recorded in a monitor log. By searching abnormal information from monitor log,the exceptions that the component has can be determined. To facilitate the searching process,string searching methods could be employed. However,current approaches are not effective enough to search long pattern string. In order to mine the specific information with less number of matches,we proposed an improved Sunday string searching algorithm in this paper. Unlike Sunday algorithm which does not make use of the already matched characters,the proposed approach presents two ideas — utilizing and recycling these characters. We take advantage of all matched characters in main string,if they are still in the matchable interval compared with pattern string,to increase the distance that pattern string moves backwards. Experimental analysis shows that,compared to Sunday algorithm,our method could greatly reduce the matching times,if the scale of character set constituting both main string and pattern string is small,or if the length of pattern string is long. Also,the proposed approach can improve the search effectiveness for abnormal information in component security testing.展开更多
Calculations and analyses are made for the ultimate composition of 158 Chinese power coals. The results reveal that the carbon content on as received basis, Cr, increases linearly with the increase of the low heating ...Calculations and analyses are made for the ultimate composition of 158 Chinese power coals. The results reveal that the carbon content on as received basis, Cr, increases linearly with the increase of the low heating value Qnot,a, on as received basis; the hydrogen content on as received basis, Hr, first increases with the increase of the volatile content on dry ash free basis Vdaf （Vdaf 〈 33.0%） and then decreases （Vdaf 〉 33.0%）; the oxygen content on as received basis, Oar, increases linearly with the increase of Vau, ranging between 2.0% and 12.5%. By comparison, the nitrogen content on as received basis N of bituminous and lean coal is higher, while the sulfur content on as received basis Sar Of anthracite is higher than bituminous coal, lean coal and lignite. The hydrogen on as received basis Hr is important for the conversion between low heating value and high heating value on as received basis for Chinese power coals, and Sr is important for the calculation of high heating value from the oxygen bomb heat value for Chinese power coals.展开更多
The conventional digital core models are usually small in size and have difficulty in representing the complex structures of heterogeneous rocks;Therefore,the parameters of simulated rock physics are difficult to be r...The conventional digital core models are usually small in size and have difficulty in representing the complex structures of heterogeneous rocks;Therefore,the parameters of simulated rock physics are difficult to be referenced.In this study,we propose a feasible simulation method for obtaining multi-scale and multi-component digital cores based on three types of sandstone samples.In the proposed method,the plug and subplug samples are scanned via micro-computed tomography at different resolutions.Furthermore,the images are precisely registered using the proposed hybrid image registration method.In case of high-resolution images,the traditional segmentation method is used to segment the cores into pores and minerals.Subsequently,we established the relations between the gray values and the porosity/mineral content in case of the low-resolution images based on the registered domains and the relation curves were applied to the segmentation of the low-resolution images.The core images constitute the multi-scale and multi-component digital core models after segmentation.Further,the elastic properties of the three samples were simulated at both fine and coarse scales based on the multi-scale and multi-component digital core models,and four component models were considered.The results show that the multi-scale and multi-component digital core models can overcome the representative limits of the conventional digital core models and accurately characterize pores and minerals at different scales.The numerical results of the elastic modulus are more representative at large scales,and considerably reliable results can be obtained by appropriately considering the minerals.展开更多
For precise plastic deformation,microstructure control is essential especially for β-solidifying γ-TiAl alloy with duplex structure.Based on stereology,the microstructure of isothermally compressed γ-TiAl alloy was...For precise plastic deformation,microstructure control is essential especially for β-solidifying γ-TiAl alloy with duplex structure.Based on stereology,the microstructure of isothermally compressed γ-TiAl alloy was divided into β_(0) grains,remnant α_(2)/γ lamellar colonies,α_(2) and γ grains.The results show that the volume fraction of β_(0) grains slightly increases in the isothermally compressed γ-TiAl alloy with the increase of height reduction.Meanwhile,the volume fractions of remnant α_(2)/γ lamellar colonies and α_(2) grains decrease.However,the volume fraction of γ grains increases from 64.39% to 78.47%.According to the quantitative results,the α→γ phase transformation was investigated in-depth,and it is found that isothermal compression accelerates the α→γ phase transformation.The first α→γ phase transformation is similar to ledge-controlled transformation,through which remnant α_(2)/γ lamellar colonies finally convert intoγgrains in isothermal compression.The second is achieved by α/γ phase interface immigration.展开更多
The deep fissured rock mass is affected by coupled effects of initial ground stress and external dynamic disturbance.In order to study the effect of internal flaw on pre-stressed rock mechanical responses and failure ...The deep fissured rock mass is affected by coupled effects of initial ground stress and external dynamic disturbance.In order to study the effect of internal flaw on pre-stressed rock mechanical responses and failure behavior under impact loading,intact granite specimens and specimens with different flaw inclinations are tested by a modified split Hopkinson pressure bar(SHPB)and digital image correlation(DIC)method.The results show that peak strain and dynamic strength of intact specimens and specimens with different flaw angles(α)decrease with the increase of axial static pressure.The 90°flaw has weak reduction effect on peak strain,dynamic strength and combined strength,while 45°and 0°flaws have remarkable reduction effect.Specimens with 90°flaw are suffered combined shear and tensile failure under middle and low axial static pre-stresses,and suffered shear failure under high axial static pre-stresses.Specimens with 45°and 0°flaws are suffered oblique shear failure caused by pre-existing flaw under different axial static pre-stresses.Besides,based on digital image correlation method,it is found that micro-cracks before formation of macro fractures(include shear and tensile fractures)belong to tensile cracks.Tensile and shear strain localizations at pre-existing flaw tip for specimen with 45°and 0°flaws are produced much earlier than that at other positions.展开更多
This paper explores the potential to use accurate but outdated channel estimates for adaptive modulation. The work is novel in that the research is conditioned on block by block adaptation. First,we define a new quant...This paper explores the potential to use accurate but outdated channel estimates for adaptive modulation. The work is novel in that the research is conditioned on block by block adaptation. First,we define a new quantity,the Tolerable Average Use Delay (TAUD),which can indicate the ability of an adaptation scheme to tolerate the delay of channel estimation results. We find that for the variable-power schemes,TAUD is a constant and dependent on the target Bit Error Rate (BER),average power and Doppler frequency; while for the constant-power schemes,it depends on the ad-aptation block length as well. At last,we investigate the relation between the delay tolerating per-formance and the spectral efficiency and give the system design criterion. The delay tolerating per-formance is improved at the price of lower data rate.展开更多
Using the recent compilation of the isotopic composition data of surface snow of Antarctic ice sheet, we proposed an improved interpolation method of δD, which utilizes geographical factors （i.e., latitude and altit...Using the recent compilation of the isotopic composition data of surface snow of Antarctic ice sheet, we proposed an improved interpolation method of δD, which utilizes geographical factors （i.e., latitude and altitude） as the primary predictors and incorporates inverse distance weighting （IDW） technique. The method was applied to a high-resolution digital elevation model （DEM） to produce a grid map of multi-year mean δD values with lkm spatial resolution for Antarctica. The mean absolute deviation between observed and estimated data in the map is about 5.4‰, and the standard deviation is 9‰. The resulting δD pattern resembles well known characteristics such as the depletion of the heavy isotopes with increasing latitude and distance from coast line, but also reveals the complex topographic effects.展开更多
Chunk alignment for the bilingual corpus is the base of Example-based Machine Translation. An anchor-based English-Chinese bilingual chunk alignment model and the corresponding algorithm of alignment are presented in ...Chunk alignment for the bilingual corpus is the base of Example-based Machine Translation. An anchor-based English-Chinese bilingual chunk alignment model and the corresponding algorithm of alignment are presented in this paper. It can effectively overcome the sparse data problem due to the limited size of the bilingual corpus. In this model, the chunk segmentation disarnbiguation is delayed to the alignment process, and hence the accuracy of chunk segmentation is improved. The experimental results demonstrate the feasibility and viability of this model.展开更多
This paper addresses some of the problems related to direct surface temperature measurement of a salient pole synchronous generator excitation winding in rotation. Excitation winding temperature is used for determinin...This paper addresses some of the problems related to direct surface temperature measurement of a salient pole synchronous generator excitation winding in rotation. Excitation winding temperature is used for determining the dynamic limit in a PQ diagram. The paper also addresses procedures of improving the accuracy of surface temperature measurement using the contact DS 18B20 digital temperature probes. The paper also provides experimental results of direct temperature measurement of the excitation winding surface conducted in the salient pole synchronous generator in the rotation.展开更多
It is discovered a new three-, four-component Petasis, Passerini, Hantzsch, Kabachnic-Fields, Ugi reactions with of arsine, stibine and bismuthine in organometallic chemistry. Modifications were replaced to a nitrogen...It is discovered a new three-, four-component Petasis, Passerini, Hantzsch, Kabachnic-Fields, Ugi reactions with of arsine, stibine and bismuthine in organometallic chemistry. Modifications were replaced to a nitrogen atom of classical reactions of atoms of phosphorus, arsenic, antimony and bismuth. It has been proposed a new mechanism for possible reactions.展开更多
In this paper, we present life and scientific work of Dr. Milog Radojcic （1903-1975）, the professor of the University of Belgrade and corresponding member of the Serbian Academy of Science and Arts. In the backgroun...In this paper, we present life and scientific work of Dr. Milog Radojcic （1903-1975）, the professor of the University of Belgrade and corresponding member of the Serbian Academy of Science and Arts. In the background of all of Radojcic＇s scientific works were the doctrine of anthroposophy and geometry as its essential part. It led him to, at the time, most contemporary problems in mathematics and mathematical physics. His interest in Medieval art reveals a personality capable to unify by itself artistic and scientific worldview. His published works were digitized in 2008 at the Mathematical Institute of the Serbian Academy of Sciences and Arts and exhibited as a part of the virtual library of the National Center for Digitization. Some of his papers, both published and unpublished ones, are extremly actual and their republishing could be very important not only for scientific but also for general public as well展开更多
The author will propose that qualia--typically understood as the purely subjective and phenomenal elements of experience--are not specifically brain processes, but are instead best thought of as world processes that c...The author will propose that qualia--typically understood as the purely subjective and phenomenal elements of experience--are not specifically brain processes, but are instead best thought of as world processes that can be characterized as distributed self-organizing networks of Whiteheadian actual entities. If this is correct, then we need not wrestle with the materialist＇s ＂hard problem＂ of explaining how consciousness can arise from the purely objective particles and forces of fundamental ptiysics, but we will need to explain in what sense microparticles and other physical objects are experiential and objectively real without embracing panpsychism. Since Whiteheadian actual entities have intrinsic natures grounding the subjective and phenomenal aspects of experience, and extrinsic relations grounding objective physical properties, we find that qualia, understood in light of Whiteheadian actual entities, can provide the metaphysical foundations for both the subjective and objective aspects of the world.展开更多
Issues specific to older migrants moving country are not yet fully understood as there are few studies on this age group. These migrants are most likely to be caught in attending to the needs of their children or thei...Issues specific to older migrants moving country are not yet fully understood as there are few studies on this age group. These migrants are most likely to be caught in attending to the needs of their children or their elderly parents, both requiring support. Over a period of two years, 35 older Polish migrants were interviewed and they told their stories of the migration experience. It was found that they had to make choices and were faced with quite difficult decisions on whether they were going to leave children or parents in Poland while they were forced into a position where they had to find work outside their own country due to age discrimination. Both men and women expressed feelings of guilt at leaving sick parents, and at not being able to afford to travel back to Poland more regularly to be with their families. Without effective cost or free digital technology, these families would not be able to sustain communication channels and relationships would break down. Consequently both the economic and emotional costs to these families and the communities in which they live could be very high.展开更多
This paper presents a component object model (COM) based framework for managing, analyzing and visualizing massive multi-scale digital elevation models (DEMs). The framework consists of a data management component (DM...This paper presents a component object model (COM) based framework for managing, analyzing and visualizing massive multi-scale digital elevation models (DEMs). The framework consists of a data management component (DMC), which is based on RDBMS/ORDBMS, a data analysis component (DAC) and a data render component (DRC). DMC can manage massive multi-scale data expressed at various reference frames within a pyramid database and can support fast access to data at variable resolution. DAC integrates many useful applied analytic functions whose results can be overlaid with the 3D scene rendered by DRC. DRC provides view-dependent data paging with the support of the underlying DMC and organizes the potential visible data at different levels into rendering.展开更多
The closed-loop stability issue of finite-precision realizations was investigated for digital control-lers implemented in block-floating-point format. The controller coefficient perturbation was analyzed resultingfrom...The closed-loop stability issue of finite-precision realizations was investigated for digital control-lers implemented in block-floating-point format. The controller coefficient perturbation was analyzed resultingfrom using finite word length (FWL) block-floating-point representation scheme. A block-floating-point FWL closed-loop stability measure was derived which considers both the dynamic range and precision. To facilitate the design of optimal finite-precision controller realizations, a computationally tractable block-floating-point FWL closed-loop stability measure was then introduced and the method of computing the value of this measure for a given controller realization was developed. The optimal controller realization is defined as the solution that maximizes the corresponding measure, and a numerical optimization approach was adopted to solve the resulting optimal realization problem. A numerical example was used to illustrate the design procedure and to compare the optimal controller realization with the initial realization.展开更多
Computer system＇s runtime information is an essential part of the digital evidence. Current digital forensic approaches mainly focus on memory and I/O data, while the runtime instructions from processes are often ign...Computer system＇s runtime information is an essential part of the digital evidence. Current digital forensic approaches mainly focus on memory and I/O data, while the runtime instructions from processes are often ignored. We present a novel approach on runtime instruction forensic analysis and have developed a forensic system which collects instruction flow and extracts digital evidence. The system is based on whole-system emulation technique and analysts are allowed to define analysis strategy to improve analysis efficiency and reduce overhead. This forensic approach and system are applicable to binary code analysis, information retrieval and matware forensics.展开更多
We propose a new scripting model for rapid and easier development of packet processing using shell scripts. In this paper we present EtherPIPE, a character network I/O device, that allows the programmer to access netw...We propose a new scripting model for rapid and easier development of packet processing using shell scripts. In this paper we present EtherPIPE, a character network I/O device, that allows the programmer to access network traffic data as a file through UNIX commands. By setting a UNIX pipe ＂r＇ from or to EtherP1PE＇s output or input with UNIX commands, packets can be easily processed, executing functions such as packet filtering, packet capturing, generating arbitrary packets, and rewriting header information. In order to prove the utilities of our model, we have developed FPGA-based EtherPIPE adapter using a commodity FPGA card and a character device driver featuring new offloading functions. With our prototype implementation, packet scripting works at 1Gbps wire-speed, receiving packets with precise hardware timestamps. This paper argues for use cases of the EtherPIPE, and discusses enhanced formats of character devices for easier network scripting.）展开更多
基金supported by the Chinese Academy of Sciences Strategic Leading Science and Technology projects(Grant No.XDB10010400)the China Postdoctoral Science Foundation(Grant No.2015M570142)
文摘The dependence of elastic moduli of shales on the mineralogy and microstructure of shales is important for the prediction of sweet spots and shale gas production. Based on 3D digital images of the microstructure of Longmaxi black shale samples using X-ray CT, we built detailed 3D digital images of cores with porosity properties and mineral contents. Next, we used finite-element （FE） methods to derive the elastic properties of the samples. The FE method can accurately model the shale mineralogy. Particular attention is paid to the derived elastic properties and their dependence on porosity and kerogen. The elastic moduli generally decrease with increasing porosity and kerogen, and there is a critical porosity （0.75） and kerogen content （ca. ≤3%） over which the elastic moduli decrease rapidly and slowly, respectively. The derived elastic moduli of gas- and oil-saturated digital cores differ little probably because of the low porosity （4.5%） of the Longmaxi black shale. Clearly, the numerical experiments demonstrated the feasibility of combining microstructure images of shale samples with elastic moduli calculations to predict shale properties.
基金supported by the National Basic Research Program of China(973 Program)(Grant No.2007CB209603)
文摘The properties of the seismic geophones are important factors for high-resolution seismic exploration and have a great influence on data quality. For this reason, we have tested three kinds of geophones currently used in several regions with different geological features： desert, saline-alkali farmland, and carbonate areas in mountainous regions in order to test their property indexes. Based on the geophone vibration equation and from the property index effects ofgeophone and the connection of the geophones on seismic data, we analyzed seismic data quality acquired inthe tested regions and suggest that suitable geophone property indexes, reasonable choice of geophone types, and the suitable geophone connection can enhance the signal/noise ratio of seismic data.
基金supported by National Natural Science Foundation of China (NSFC grant number:61202110,61401180 and 61502205)the Postdoctoral Science Foundation of China (Grant number:2015M571687 and 2015M581739)the Graduate Research Innovation Project of Jiangsu Province(KYLX15_1079 and KYLX16_0900)
文摘In the execution of method invocation sequences to test component security,abnormal or normal information is generated and recorded in a monitor log. By searching abnormal information from monitor log,the exceptions that the component has can be determined. To facilitate the searching process,string searching methods could be employed. However,current approaches are not effective enough to search long pattern string. In order to mine the specific information with less number of matches,we proposed an improved Sunday string searching algorithm in this paper. Unlike Sunday algorithm which does not make use of the already matched characters,the proposed approach presents two ideas — utilizing and recycling these characters. We take advantage of all matched characters in main string,if they are still in the matchable interval compared with pattern string,to increase the distance that pattern string moves backwards. Experimental analysis shows that,compared to Sunday algorithm,our method could greatly reduce the matching times,if the scale of character set constituting both main string and pattern string is small,or if the length of pattern string is long. Also,the proposed approach can improve the search effectiveness for abnormal information in component security testing.
文摘Calculations and analyses are made for the ultimate composition of 158 Chinese power coals. The results reveal that the carbon content on as received basis, Cr, increases linearly with the increase of the low heating value Qnot,a, on as received basis; the hydrogen content on as received basis, Hr, first increases with the increase of the volatile content on dry ash free basis Vdaf （Vdaf 〈 33.0%） and then decreases （Vdaf 〉 33.0%）; the oxygen content on as received basis, Oar, increases linearly with the increase of Vau, ranging between 2.0% and 12.5%. By comparison, the nitrogen content on as received basis N of bituminous and lean coal is higher, while the sulfur content on as received basis Sar Of anthracite is higher than bituminous coal, lean coal and lignite. The hydrogen on as received basis Hr is important for the conversion between low heating value and high heating value on as received basis for Chinese power coals, and Sr is important for the calculation of high heating value from the oxygen bomb heat value for Chinese power coals.
基金supported by the National Natural Science Foundation of China Research(Nos.41574122 and 41374124)National Science and Technology major Project(No.2016ZX05006002-004)。
文摘The conventional digital core models are usually small in size and have difficulty in representing the complex structures of heterogeneous rocks;Therefore,the parameters of simulated rock physics are difficult to be referenced.In this study,we propose a feasible simulation method for obtaining multi-scale and multi-component digital cores based on three types of sandstone samples.In the proposed method,the plug and subplug samples are scanned via micro-computed tomography at different resolutions.Furthermore,the images are precisely registered using the proposed hybrid image registration method.In case of high-resolution images,the traditional segmentation method is used to segment the cores into pores and minerals.Subsequently,we established the relations between the gray values and the porosity/mineral content in case of the low-resolution images based on the registered domains and the relation curves were applied to the segmentation of the low-resolution images.The core images constitute the multi-scale and multi-component digital core models after segmentation.Further,the elastic properties of the three samples were simulated at both fine and coarse scales based on the multi-scale and multi-component digital core models,and four component models were considered.The results show that the multi-scale and multi-component digital core models can overcome the representative limits of the conventional digital core models and accurately characterize pores and minerals at different scales.The numerical results of the elastic modulus are more representative at large scales,and considerably reliable results can be obtained by appropriately considering the minerals.
基金the financial supports from the National Natural Science Foundation of China(No.51975478)the Fundamental Research Funds for the Central Universities,China(No.3102019MS0403).
文摘For precise plastic deformation,microstructure control is essential especially for β-solidifying γ-TiAl alloy with duplex structure.Based on stereology,the microstructure of isothermally compressed γ-TiAl alloy was divided into β_(0) grains,remnant α_(2)/γ lamellar colonies,α_(2) and γ grains.The results show that the volume fraction of β_(0) grains slightly increases in the isothermally compressed γ-TiAl alloy with the increase of height reduction.Meanwhile,the volume fractions of remnant α_(2)/γ lamellar colonies and α_(2) grains decrease.However,the volume fraction of γ grains increases from 64.39% to 78.47%.According to the quantitative results,the α→γ phase transformation was investigated in-depth,and it is found that isothermal compression accelerates the α→γ phase transformation.The first α→γ phase transformation is similar to ledge-controlled transformation,through which remnant α_(2)/γ lamellar colonies finally convert intoγgrains in isothermal compression.The second is achieved by α/γ phase interface immigration.
基金Project(2019JJ20028)supported by the Outstanding Youth Science Foundations of Hunan Province of ChinaProject(51774321)supported by the National Natural Science Foundation of ChinaProject(2018YFC0604606)supported by the State Key Research Development Program of China。
文摘The deep fissured rock mass is affected by coupled effects of initial ground stress and external dynamic disturbance.In order to study the effect of internal flaw on pre-stressed rock mechanical responses and failure behavior under impact loading,intact granite specimens and specimens with different flaw inclinations are tested by a modified split Hopkinson pressure bar(SHPB)and digital image correlation(DIC)method.The results show that peak strain and dynamic strength of intact specimens and specimens with different flaw angles(α)decrease with the increase of axial static pressure.The 90°flaw has weak reduction effect on peak strain,dynamic strength and combined strength,while 45°and 0°flaws have remarkable reduction effect.Specimens with 90°flaw are suffered combined shear and tensile failure under middle and low axial static pre-stresses,and suffered shear failure under high axial static pre-stresses.Specimens with 45°and 0°flaws are suffered oblique shear failure caused by pre-existing flaw under different axial static pre-stresses.Besides,based on digital image correlation method,it is found that micro-cracks before formation of macro fractures(include shear and tensile fractures)belong to tensile cracks.Tensile and shear strain localizations at pre-existing flaw tip for specimen with 45°and 0°flaws are produced much earlier than that at other positions.
基金Supported by the National Natural Science Foundation of China (No.60496311).
文摘This paper explores the potential to use accurate but outdated channel estimates for adaptive modulation. The work is novel in that the research is conditioned on block by block adaptation. First,we define a new quantity,the Tolerable Average Use Delay (TAUD),which can indicate the ability of an adaptation scheme to tolerate the delay of channel estimation results. We find that for the variable-power schemes,TAUD is a constant and dependent on the target Bit Error Rate (BER),average power and Doppler frequency; while for the constant-power schemes,it depends on the ad-aptation block length as well. At last,we investigate the relation between the delay tolerating per-formance and the spectral efficiency and give the system design criterion. The delay tolerating per-formance is improved at the price of lower data rate.
基金Under the auspices of National Natural Science Foundation of China (No. 40825017, 40576001)100 Talents Project of Chinese Academy of SciencesNational Key Technologies R&D Program of China (No. 2006BAB18B01)
文摘Using the recent compilation of the isotopic composition data of surface snow of Antarctic ice sheet, we proposed an improved interpolation method of δD, which utilizes geographical factors （i.e., latitude and altitude） as the primary predictors and incorporates inverse distance weighting （IDW） technique. The method was applied to a high-resolution digital elevation model （DEM） to produce a grid map of multi-year mean δD values with lkm spatial resolution for Antarctica. The mean absolute deviation between observed and estimated data in the map is about 5.4‰, and the standard deviation is 9‰. The resulting δD pattern resembles well known characteristics such as the depletion of the heavy isotopes with increasing latitude and distance from coast line, but also reveals the complex topographic effects.
文摘Chunk alignment for the bilingual corpus is the base of Example-based Machine Translation. An anchor-based English-Chinese bilingual chunk alignment model and the corresponding algorithm of alignment are presented in this paper. It can effectively overcome the sparse data problem due to the limited size of the bilingual corpus. In this model, the chunk segmentation disarnbiguation is delayed to the alignment process, and hence the accuracy of chunk segmentation is improved. The experimental results demonstrate the feasibility and viability of this model.
文摘This paper addresses some of the problems related to direct surface temperature measurement of a salient pole synchronous generator excitation winding in rotation. Excitation winding temperature is used for determining the dynamic limit in a PQ diagram. The paper also addresses procedures of improving the accuracy of surface temperature measurement using the contact DS 18B20 digital temperature probes. The paper also provides experimental results of direct temperature measurement of the excitation winding surface conducted in the salient pole synchronous generator in the rotation.
文摘It is discovered a new three-, four-component Petasis, Passerini, Hantzsch, Kabachnic-Fields, Ugi reactions with of arsine, stibine and bismuthine in organometallic chemistry. Modifications were replaced to a nitrogen atom of classical reactions of atoms of phosphorus, arsenic, antimony and bismuth. It has been proposed a new mechanism for possible reactions.
文摘In this paper, we present life and scientific work of Dr. Milog Radojcic （1903-1975）, the professor of the University of Belgrade and corresponding member of the Serbian Academy of Science and Arts. In the background of all of Radojcic＇s scientific works were the doctrine of anthroposophy and geometry as its essential part. It led him to, at the time, most contemporary problems in mathematics and mathematical physics. His interest in Medieval art reveals a personality capable to unify by itself artistic and scientific worldview. His published works were digitized in 2008 at the Mathematical Institute of the Serbian Academy of Sciences and Arts and exhibited as a part of the virtual library of the National Center for Digitization. Some of his papers, both published and unpublished ones, are extremly actual and their republishing could be very important not only for scientific but also for general public as well
文摘The author will propose that qualia--typically understood as the purely subjective and phenomenal elements of experience--are not specifically brain processes, but are instead best thought of as world processes that can be characterized as distributed self-organizing networks of Whiteheadian actual entities. If this is correct, then we need not wrestle with the materialist＇s ＂hard problem＂ of explaining how consciousness can arise from the purely objective particles and forces of fundamental ptiysics, but we will need to explain in what sense microparticles and other physical objects are experiential and objectively real without embracing panpsychism. Since Whiteheadian actual entities have intrinsic natures grounding the subjective and phenomenal aspects of experience, and extrinsic relations grounding objective physical properties, we find that qualia, understood in light of Whiteheadian actual entities, can provide the metaphysical foundations for both the subjective and objective aspects of the world.
文摘Issues specific to older migrants moving country are not yet fully understood as there are few studies on this age group. These migrants are most likely to be caught in attending to the needs of their children or their elderly parents, both requiring support. Over a period of two years, 35 older Polish migrants were interviewed and they told their stories of the migration experience. It was found that they had to make choices and were faced with quite difficult decisions on whether they were going to leave children or parents in Poland while they were forced into a position where they had to find work outside their own country due to age discrimination. Both men and women expressed feelings of guilt at leaving sick parents, and at not being able to afford to travel back to Poland more regularly to be with their families. Without effective cost or free digital technology, these families would not be able to sustain communication channels and relationships would break down. Consequently both the economic and emotional costs to these families and the communities in which they live could be very high.
文摘This paper presents a component object model (COM) based framework for managing, analyzing and visualizing massive multi-scale digital elevation models (DEMs). The framework consists of a data management component (DMC), which is based on RDBMS/ORDBMS, a data analysis component (DAC) and a data render component (DRC). DMC can manage massive multi-scale data expressed at various reference frames within a pyramid database and can support fast access to data at variable resolution. DAC integrates many useful applied analytic functions whose results can be overlaid with the 3D scene rendered by DRC. DRC provides view-dependent data paging with the support of the underlying DMC and organizes the potential visible data at different levels into rendering.
文摘The closed-loop stability issue of finite-precision realizations was investigated for digital control-lers implemented in block-floating-point format. The controller coefficient perturbation was analyzed resultingfrom using finite word length (FWL) block-floating-point representation scheme. A block-floating-point FWL closed-loop stability measure was derived which considers both the dynamic range and precision. To facilitate the design of optimal finite-precision controller realizations, a computationally tractable block-floating-point FWL closed-loop stability measure was then introduced and the method of computing the value of this measure for a given controller realization was developed. The optimal controller realization is defined as the solution that maximizes the corresponding measure, and a numerical optimization approach was adopted to solve the resulting optimal realization problem. A numerical example was used to illustrate the design procedure and to compare the optimal controller realization with the initial realization.
文摘Computer system＇s runtime information is an essential part of the digital evidence. Current digital forensic approaches mainly focus on memory and I/O data, while the runtime instructions from processes are often ignored. We present a novel approach on runtime instruction forensic analysis and have developed a forensic system which collects instruction flow and extracts digital evidence. The system is based on whole-system emulation technique and analysts are allowed to define analysis strategy to improve analysis efficiency and reduce overhead. This forensic approach and system are applicable to binary code analysis, information retrieval and matware forensics.
文摘We propose a new scripting model for rapid and easier development of packet processing using shell scripts. In this paper we present EtherPIPE, a character network I/O device, that allows the programmer to access network traffic data as a file through UNIX commands. By setting a UNIX pipe ＂r＇ from or to EtherP1PE＇s output or input with UNIX commands, packets can be easily processed, executing functions such as packet filtering, packet capturing, generating arbitrary packets, and rewriting header information. In order to prove the utilities of our model, we have developed FPGA-based EtherPIPE adapter using a commodity FPGA card and a character device driver featuring new offloading functions. With our prototype implementation, packet scripting works at 1Gbps wire-speed, receiving packets with precise hardware timestamps. This paper argues for use cases of the EtherPIPE, and discusses enhanced formats of character devices for easier network scripting.）
