With the development of Internet and information technology, the digital crimes are also on the rise. Computer forensics is an emerging research area that applies computer investigation and analysis techniques to help...With the development of Internet and information technology, the digital crimes are also on the rise. Computer forensics is an emerging research area that applies computer investigation and analysis techniques to help detection of these crimes and gathering of digital evidence suitable for presentation in courts. This paper provides foundational concept of computer forensics, outlines various principles of computer forensics, discusses the model of computer forensics and presents a proposed model.展开更多
SLAM is one of the most important components in robot navigation. A SLAM algorithm based on image sequences captured by a single digital camera is proposed in this paper. By this algorithm, SIFT feature points are sel...SLAM is one of the most important components in robot navigation. A SLAM algorithm based on image sequences captured by a single digital camera is proposed in this paper. By this algorithm, SIFT feature points are selected and matched between image pairs sequentially. After three images have been captured, the environment’s 3D map and the camera’s positions are initialized based on matched feature points and intrinsic parameters of the camera. A robust method is applied to estimate the position and orientation of the camera in the forthcoming images. Finally, a robust adaptive bundle adjustment algorithm is adopted to optimize the environment’s 3D map and the camera’s positions simultaneously. Results of quantitative and qualitative experiments show that our algorithm can reconstruct the environment and localize the camera accurately and efficiently.展开更多
Using the method of numerical matrix diagonalization within the effective-mass approximation, we investigated a D^--center quantum dot system subjected to a Gaussian potential confinement. We obtain the dependence of ...Using the method of numerical matrix diagonalization within the effective-mass approximation, we investigated a D^--center quantum dot system subjected to a Gaussian potential confinement. We obtain the dependence of binding energies of the ground-states of the D^--center on the depth of Gaussian potential and the magnetic field strength. The result shows clearly that the binding energies of the ground-states of the D^--center are rather sensitive to the depth of potential and the strength of magnetic field.展开更多
The finiteness of superstring theory at each order in perturbation theory is considered with respect to the ten-dimensional effective action. The quantum consistency of the ten-dimensional superstring effective action...The finiteness of superstring theory at each order in perturbation theory is considered with respect to the ten-dimensional effective action. The quantum consistency of the ten-dimensional superstring effective action is confirmed with an analysis of the perturbative expansion of the quartic sector. It is found to be compatible with the finiteness of reduced four-dimensional theory. Furthermore, implications for the validity of superstring perturbation theory at lower energies is considered.展开更多
Taking Shenzhen city as an example, the statistical and physical relationship between the density of pollutants and various atmospheric parameters are analyzed in detail, and a space-partitioned city air pollution pot...Taking Shenzhen city as an example, the statistical and physical relationship between the density of pollutants and various atmospheric parameters are analyzed in detail, and a space-partitioned city air pollution potential prediction scheme is established based on it. The scheme considers quantitatively more than ten factors at the surface and planetary boundary layer (PBL), especially the effects of anisotropy of geographical environment, and treats wind direction as an independent impact factor. While the scheme treats the prediction equation respectively for different pollutants according to their differences in dilute properties, it considers as well the possible differences in dilute properties at different districts of the city under the same atmospheric condition, treating predictions respectively for different districts. Finally, the temporally and spatially high resolution predictions for the atmospheric factors are made with a high resolution numerical model, and further the space-partitioned and time-variational city pollution potential predictions are made. The scheme is objective and quantitative, and with clear physical meaning, so it is suitable to use in making high resolution air pollution predictions.展开更多
Language, reading, and reading-related tasks were administered to 148 children from lower primary （Standard 1, 2, and 3） in Kenyan schools. The aim was to investigate the literacy developmental trends across the yea...Language, reading, and reading-related tasks were administered to 148 children from lower primary （Standard 1, 2, and 3） in Kenyan schools. The aim was to investigate the literacy developmental trends across the years and establish which of the two variables, word identification skills or target language oral proficiency influenced reading comprehension performance. The results indicated that word identification skills independently influenced reading comprehension performance in both standard 2 and standard 3 classes, but target language oral skills did not. Further, the analysis of invented spelling task performance revealed evidence of transfer of alphabetic coding skills of first language to English orthography. The spelling errors reflected letter-sound patterns not found in English orthography. Analysis of the miscues in the spelling task revealed that children rely on first language phonological processes to spell target language unfamiliar words as long the languages have a common alphabetic system.展开更多
Efficient numerical solver for the SchrSdinger equation is very important in physics and chemistry. The finite element discrete variable representation （FE-DVR） was first proposed by Rescigno and Mc-Curdy [Phys. Rev...Efficient numerical solver for the SchrSdinger equation is very important in physics and chemistry. The finite element discrete variable representation （FE-DVR） was first proposed by Rescigno and Mc-Curdy [Phys. Rev. A 62, 032706 （2000）] for solving quantum-mechanical scattering problems. In this work, an FE-DVR method in a mapped coordinate was proposed to improve the efficiency of the original FE-DVR method. For numerical demonstration, the proposed approach is applied for solving the electronic eigenfunctions and eigenvalues of the hydrogen atom and vibrational states of the electronic state 3E＋ of the Cs2 molecule which has long-range interaction potential. The numerical results indicate that the numerical efficiency of the original FE-DVR has been improved much using our proposed mapped coordinate scheme.展开更多
The initiation of the National New Drug Innovation Key Technology Program marked a strategic shift of new drug discovery in China, which will greatly enhance the new drug discovery research activities. It presents a v...The initiation of the National New Drug Innovation Key Technology Program marked a strategic shift of new drug discovery in China, which will greatly enhance the new drug discovery research activities. It presents a valuable opportunity for the growth and quality advancement of pharmaceutical science journals. As the only comprehensive English journal of the Chinese Pharmaceutical Association, In the new situation, Journal of Chinese Pharmaceutical Sciences （JCPS） plays a critical role in the communication of new discoveries in pharmaceutical researches to the scientific community. To fulfill the roles as an internationally recognized platform for the communication of the new drug discoveries supported by the National New Drug Innovation Programs, the JCPS editorial office will take advantage of its English language specialty, emphasize quality and digital access, and promote the advancement of the journal.展开更多
We propose a position sensorless control scheme for a four-switch,three-phase brushless DC motor drive,based on the zero crossing point detection of phase back-EMF voltages using newly defined error functions(EFs). Th...We propose a position sensorless control scheme for a four-switch,three-phase brushless DC motor drive,based on the zero crossing point detection of phase back-EMF voltages using newly defined error functions(EFs). The commutation in-stants are 30° after detected zero crossing points of the EFs. Developed EFs have greater magnitude rather than phase or line voltages so that the sensorless control can work at a lower speed range. Moreover,EFs have smooth transitions around zero voltage level that reduces the commutation errors. EFs are derived from the filtered terminal voltages vao and vbo of two low-pass filters,which are used to eliminate high frequency noises for calculation of the average terminal voltages. The feasibility of the proposed sensorless control is demonstrated by simulation and experimental results.展开更多
文摘With the development of Internet and information technology, the digital crimes are also on the rise. Computer forensics is an emerging research area that applies computer investigation and analysis techniques to help detection of these crimes and gathering of digital evidence suitable for presentation in courts. This paper provides foundational concept of computer forensics, outlines various principles of computer forensics, discusses the model of computer forensics and presents a proposed model.
基金Project supported by the National Natural Science Foundation of China (Nos. 60534070 and 60502006)the Science and Tech-nology Department of Zhejiang Province (No. 2005C14008), China
文摘SLAM is one of the most important components in robot navigation. A SLAM algorithm based on image sequences captured by a single digital camera is proposed in this paper. By this algorithm, SIFT feature points are selected and matched between image pairs sequentially. After three images have been captured, the environment’s 3D map and the camera’s positions are initialized based on matched feature points and intrinsic parameters of the camera. A robust method is applied to estimate the position and orientation of the camera in the forthcoming images. Finally, a robust adaptive bundle adjustment algorithm is adopted to optimize the environment’s 3D map and the camera’s positions simultaneously. Results of quantitative and qualitative experiments show that our algorithm can reconstruct the environment and localize the camera accurately and efficiently.
基金Thc project supported by National Natural Science Foundation of China under Grant Nos. 10475021 and 10275014
文摘Using the method of numerical matrix diagonalization within the effective-mass approximation, we investigated a D^--center quantum dot system subjected to a Gaussian potential confinement. We obtain the dependence of binding energies of the ground-states of the D^--center on the depth of Gaussian potential and the magnetic field strength. The result shows clearly that the binding energies of the ground-states of the D^--center are rather sensitive to the depth of potential and the strength of magnetic field.
文摘The finiteness of superstring theory at each order in perturbation theory is considered with respect to the ten-dimensional effective action. The quantum consistency of the ten-dimensional superstring effective action is confirmed with an analysis of the perturbative expansion of the quartic sector. It is found to be compatible with the finiteness of reduced four-dimensional theory. Furthermore, implications for the validity of superstring perturbation theory at lower energies is considered.
文摘Taking Shenzhen city as an example, the statistical and physical relationship between the density of pollutants and various atmospheric parameters are analyzed in detail, and a space-partitioned city air pollution potential prediction scheme is established based on it. The scheme considers quantitatively more than ten factors at the surface and planetary boundary layer (PBL), especially the effects of anisotropy of geographical environment, and treats wind direction as an independent impact factor. While the scheme treats the prediction equation respectively for different pollutants according to their differences in dilute properties, it considers as well the possible differences in dilute properties at different districts of the city under the same atmospheric condition, treating predictions respectively for different districts. Finally, the temporally and spatially high resolution predictions for the atmospheric factors are made with a high resolution numerical model, and further the space-partitioned and time-variational city pollution potential predictions are made. The scheme is objective and quantitative, and with clear physical meaning, so it is suitable to use in making high resolution air pollution predictions.
文摘Language, reading, and reading-related tasks were administered to 148 children from lower primary （Standard 1, 2, and 3） in Kenyan schools. The aim was to investigate the literacy developmental trends across the years and establish which of the two variables, word identification skills or target language oral proficiency influenced reading comprehension performance. The results indicated that word identification skills independently influenced reading comprehension performance in both standard 2 and standard 3 classes, but target language oral skills did not. Further, the analysis of invented spelling task performance revealed evidence of transfer of alphabetic coding skills of first language to English orthography. The spelling errors reflected letter-sound patterns not found in English orthography. Analysis of the miscues in the spelling task revealed that children rely on first language phonological processes to spell target language unfamiliar words as long the languages have a common alphabetic system.
文摘Efficient numerical solver for the SchrSdinger equation is very important in physics and chemistry. The finite element discrete variable representation （FE-DVR） was first proposed by Rescigno and Mc-Curdy [Phys. Rev. A 62, 032706 （2000）] for solving quantum-mechanical scattering problems. In this work, an FE-DVR method in a mapped coordinate was proposed to improve the efficiency of the original FE-DVR method. For numerical demonstration, the proposed approach is applied for solving the electronic eigenfunctions and eigenvalues of the hydrogen atom and vibrational states of the electronic state 3E＋ of the Cs2 molecule which has long-range interaction potential. The numerical results indicate that the numerical efficiency of the original FE-DVR has been improved much using our proposed mapped coordinate scheme.
文摘The initiation of the National New Drug Innovation Key Technology Program marked a strategic shift of new drug discovery in China, which will greatly enhance the new drug discovery research activities. It presents a valuable opportunity for the growth and quality advancement of pharmaceutical science journals. As the only comprehensive English journal of the Chinese Pharmaceutical Association, In the new situation, Journal of Chinese Pharmaceutical Sciences （JCPS） plays a critical role in the communication of new discoveries in pharmaceutical researches to the scientific community. To fulfill the roles as an internationally recognized platform for the communication of the new drug discoveries supported by the National New Drug Innovation Programs, the JCPS editorial office will take advantage of its English language specialty, emphasize quality and digital access, and promote the advancement of the journal.
文摘We propose a position sensorless control scheme for a four-switch,three-phase brushless DC motor drive,based on the zero crossing point detection of phase back-EMF voltages using newly defined error functions(EFs). The commutation in-stants are 30° after detected zero crossing points of the EFs. Developed EFs have greater magnitude rather than phase or line voltages so that the sensorless control can work at a lower speed range. Moreover,EFs have smooth transitions around zero voltage level that reduces the commutation errors. EFs are derived from the filtered terminal voltages vao and vbo of two low-pass filters,which are used to eliminate high frequency noises for calculation of the average terminal voltages. The feasibility of the proposed sensorless control is demonstrated by simulation and experimental results.
