In this paper we deduce the analytic solutions of the first- and second-order vertical derivative zero points for gravity anomalies in simple regular models with single, double, and multiple edges and analyze their sp...In this paper we deduce the analytic solutions of the first- and second-order vertical derivative zero points for gravity anomalies in simple regular models with single, double, and multiple edges and analyze their spatial variation. For another simple regular models where it is difficult to obtain the analytic expression of the zero point, we try to use the profile zero points to analyze the spatial variation. The test results show that the spatial variation laws of both first- and second-order vertical derivative zero points are almost the same but the second-order derivative zero point position is closer to the top surface edge of the geological bodies than the first-order vertical derivative and has a relatively high resolution. Moreover, with an increase in buried depth, for a single boundary model, the vertical derivative zero point location tends to move from the top surface edge to the outside of the buried body but finally converges to a fixed value. For a double boundary model, the vertical derivative zero point location tends to migrate from the top surface edge to the outside of the buried body. For multiple boundary models, the vertical derivative zero point location converges from the top surface edge to the outside of the buried body where some zero points coincide and finally vanish. Finally, the effectiveness and reliability of the proposed method is verified using real field data.展开更多
This study investigates the stability problem of gob-side entry retaining (GER) and backfilling wall which located under the key block B. Based on the combined research of elastic-plastic mechanics, structure mechan...This study investigates the stability problem of gob-side entry retaining (GER) and backfilling wall which located under the key block B. Based on the combined research of elastic-plastic mechanics, structure mechanics and modern theory of mining-induced pressure, the caving characteristic and roof structure over the GER were analyzed, and the vertical force and the torque on retained entry roof were also derived as the position for the retained entry varies. On the basis of the specific geology in Huainan mining area, the results indicate that a relatively more stable position for retained entry neighbors the hinge point of block A and B, and it also located at a scope ranging from this point to the one-third length of block B in horizontal direction. As to appropriate position for backfilling wall, this study recommends partial- road-in backfilling method for GER. Field trial conducted at panel face 12418 of Xieqiao Mine demonstrates that the recommended width for original entry is 3.6 m and the preferred width proportion between original retained entry and original entry is 75 % or so whereas the avoidable one is 88 % or so. These findings provide qualitative references to the mines which share similar geology as what Huainan mining area characterized.展开更多
Objective: The aim of this study was to evaluate the utility of an upright-type 11-gauge stereotactic vacuumassisted biopsy device (Mammotome) for the diagnosis of breast microcalcifications Methods: Between May 2001 ...Objective: The aim of this study was to evaluate the utility of an upright-type 11-gauge stereotactic vacuumassisted biopsy device (Mammotome) for the diagnosis of breast microcalcifications Methods: Between May 2001 and October 2005, 154 biopsies in 152 patients with microcalcifications were performed using the upright-type 11-gauge stereotactic vacuum-assisted biopsy device. Patients in whom this biopsy was diagnosed as carcinoma or a borderline lesion, had a subsequent surgical excision of the lesion. Histopathological and radiological features of the two specimens were then compared with each other. Results: Microcalcification was identified on specimen mammograms and microscopic slides in 97.4% of cases. Of 154 Mammotome biopsies 98 (63.6%) were benign, 51 (33.1%) were malignant, 3 (1.9%) showed atypical hyperplasia, and 2 (1.3%) were indeterminate, respectively. Of the 48 cases that received surgical excision, 6 of 36 ductal carcinomas in situ (16.7%) upstaged to invasive ductal carcinoma and 1 of 2 atypical ductal hyperplasias was upstaged to ductal carcinoma in situ. The positive predictive value of the 11-gauge Mammotome for the diagnosis of invasion in breast cancer was 100%. Linear calcification and pleomorphic calcification linear/segmental distribution was reliable indications of malignancy. The mean follow-up time of the benign lesions was 22 months, and without evidence of lesion growth. Complications included vasovagal reactions (6.3%), bleeding (0.6%) and hematoma (2.6%). Conclusion: The upright stereotactic 11-gauge Mammotome procedure is an effective and reliable method for the diagnosis of breast microcalcifications. It has minimal side effects. For lesions diagnosed as ADH or DCIS with the 11-gauge Mammotome, subsequent surgical excision should be performed.展开更多
With the rapid growth of coal chemical industry in China, the selection and application of Air Separation Unit(ASU) became very important. As the core unit in coal chemical industry, ASU will greatly impact the engine...With the rapid growth of coal chemical industry in China, the selection and application of Air Separation Unit(ASU) became very important. As the core unit in coal chemical industry, ASU will greatly impact the engineering construction and operation/production of coal chemical business. In this paper, major suppliers of ASU at home and abroad were reviewed, and the major supplying status of ASU in China was introduced. The ASUs in operation of SINOPEC were listed and discussed. On this basis, some suggestions of ASU selection strategies were provided on localization, standardization and operation methods.展开更多
An air dense medium fluidized bed separator(ADMFBS) is used for dry beneficiation of coal using ultrafine magnetite particles as a pseudo-fluid medium. In this process, the coal particle gains additional weight due to...An air dense medium fluidized bed separator(ADMFBS) is used for dry beneficiation of coal using ultrafine magnetite particles as a pseudo-fluid medium. In this process, the coal particle gains additional weight due to coating on its surface and deposition at dead zone area by fine magnetite particles.Hence, the effective density of coal particle increases and the position of coal particle changes accordingly. In this work, an attempt was made to predict the position of coal particle in non-bubbling condition dense medium fluidized bed system. Coal particles of different shape such as cubical, rectangular prism,spherical and triangular prism with different projected area and density were used. The results show that the position of coal particle in air dense medium fluidized bed follows descending order with respect to the increase of density, projected area of coal particle and different shapes(i.e., triangular prism, cubical,rectangular prism and spherical). Empirical mathematical correlations were developed to predict the position of coal particle.展开更多
This paper presents a robust object tracking approach via a spatially constrained colour model. Local image patches of the object and spatial relation between these patches are informative and stable during object tra...This paper presents a robust object tracking approach via a spatially constrained colour model. Local image patches of the object and spatial relation between these patches are informative and stable during object tracking. So, we propose to partition an object into patches and develop a Spatially Constrained Colour Model (SCCM) by combining the colour distributions and spatial configuration of these patches. The likelihood of the candidate object is given by estimating the confidences of the pixels in the candidate object region. The appearance model is learnt from the first frame and the tracking is carried out by particle filter. The experimental results show that the proposed tracking approach can accurately track the object with scale changes, pose variance and partial occlusion.展开更多
The configuration space is a fundamental concept that is widely used in algorithmic robotics. Many applications in robotics, computer-aided design, and related areas can be reduced to computational problems in terms o...The configuration space is a fundamental concept that is widely used in algorithmic robotics. Many applications in robotics, computer-aided design, and related areas can be reduced to computational problems in terms of configuration spaces. In this paper, we survey some of our recent work on solving two important challenges related to configuration spaces: ~ how to efficiently compute an approximate representation of high-dimensional configuration spaces; and how to efficiently perform geometric proximity and motion planning queries (n high-dimensional configuration spaces. We present new configuration space construction algorithms based on machine learning and geometric approximation techniques. These algorithms perform collision queries on many configuration samples. The collision query results are used to compute an approximate representation for the configuration space, which quickly converges to the exact configuration space. We also present parallel GPU-based algorithms to accelerate the performance of optimization and search computations in configuration spaces. In particular, we design efficient GPU-based parallel k-nearest neighbor and parallel collision detection algorithms and use these algorithms to accelerate motion planning.展开更多
This paper presents a trust region algorithm with null space technique fornonlinear equality constrained optimization. Considering in the null space methods that,the convergent rate of range space step is faster than ...This paper presents a trust region algorithm with null space technique fornonlinear equality constrained optimization. Considering in the null space methods that,the convergent rate of range space step is faster than the null space step for the most cases,the proposed algorithm computes null steps more often than range space step. Moreover,the new algorithm is based on the reduced Hessian SQP method. Global convergence ofthe proposed algorithm is proved. The effectiveness of the method is demonstrated bysome numerical examples.展开更多
基金jointly supported by the National Major Science and Technology Program (No. 2008ZX05025)the National 973 Program (Grant No. 2009CB219400)
文摘In this paper we deduce the analytic solutions of the first- and second-order vertical derivative zero points for gravity anomalies in simple regular models with single, double, and multiple edges and analyze their spatial variation. For another simple regular models where it is difficult to obtain the analytic expression of the zero point, we try to use the profile zero points to analyze the spatial variation. The test results show that the spatial variation laws of both first- and second-order vertical derivative zero points are almost the same but the second-order derivative zero point position is closer to the top surface edge of the geological bodies than the first-order vertical derivative and has a relatively high resolution. Moreover, with an increase in buried depth, for a single boundary model, the vertical derivative zero point location tends to move from the top surface edge to the outside of the buried body but finally converges to a fixed value. For a double boundary model, the vertical derivative zero point location tends to migrate from the top surface edge to the outside of the buried body. For multiple boundary models, the vertical derivative zero point location converges from the top surface edge to the outside of the buried body where some zero points coincide and finally vanish. Finally, the effectiveness and reliability of the proposed method is verified using real field data.
文摘This study investigates the stability problem of gob-side entry retaining (GER) and backfilling wall which located under the key block B. Based on the combined research of elastic-plastic mechanics, structure mechanics and modern theory of mining-induced pressure, the caving characteristic and roof structure over the GER were analyzed, and the vertical force and the torque on retained entry roof were also derived as the position for the retained entry varies. On the basis of the specific geology in Huainan mining area, the results indicate that a relatively more stable position for retained entry neighbors the hinge point of block A and B, and it also located at a scope ranging from this point to the one-third length of block B in horizontal direction. As to appropriate position for backfilling wall, this study recommends partial- road-in backfilling method for GER. Field trial conducted at panel face 12418 of Xieqiao Mine demonstrates that the recommended width for original entry is 3.6 m and the preferred width proportion between original retained entry and original entry is 75 % or so whereas the avoidable one is 88 % or so. These findings provide qualitative references to the mines which share similar geology as what Huainan mining area characterized.
基金Supported by a grant from the Sasakawa Foundation (Japan) of Japan China Medical Association
文摘Objective: The aim of this study was to evaluate the utility of an upright-type 11-gauge stereotactic vacuumassisted biopsy device (Mammotome) for the diagnosis of breast microcalcifications Methods: Between May 2001 and October 2005, 154 biopsies in 152 patients with microcalcifications were performed using the upright-type 11-gauge stereotactic vacuum-assisted biopsy device. Patients in whom this biopsy was diagnosed as carcinoma or a borderline lesion, had a subsequent surgical excision of the lesion. Histopathological and radiological features of the two specimens were then compared with each other. Results: Microcalcification was identified on specimen mammograms and microscopic slides in 97.4% of cases. Of 154 Mammotome biopsies 98 (63.6%) were benign, 51 (33.1%) were malignant, 3 (1.9%) showed atypical hyperplasia, and 2 (1.3%) were indeterminate, respectively. Of the 48 cases that received surgical excision, 6 of 36 ductal carcinomas in situ (16.7%) upstaged to invasive ductal carcinoma and 1 of 2 atypical ductal hyperplasias was upstaged to ductal carcinoma in situ. The positive predictive value of the 11-gauge Mammotome for the diagnosis of invasion in breast cancer was 100%. Linear calcification and pleomorphic calcification linear/segmental distribution was reliable indications of malignancy. The mean follow-up time of the benign lesions was 22 months, and without evidence of lesion growth. Complications included vasovagal reactions (6.3%), bleeding (0.6%) and hematoma (2.6%). Conclusion: The upright stereotactic 11-gauge Mammotome procedure is an effective and reliable method for the diagnosis of breast microcalcifications. It has minimal side effects. For lesions diagnosed as ADH or DCIS with the 11-gauge Mammotome, subsequent surgical excision should be performed.
文摘With the rapid growth of coal chemical industry in China, the selection and application of Air Separation Unit(ASU) became very important. As the core unit in coal chemical industry, ASU will greatly impact the engineering construction and operation/production of coal chemical business. In this paper, major suppliers of ASU at home and abroad were reviewed, and the major supplying status of ASU in China was introduced. The ASUs in operation of SINOPEC were listed and discussed. On this basis, some suggestions of ASU selection strategies were provided on localization, standardization and operation methods.
文摘An air dense medium fluidized bed separator(ADMFBS) is used for dry beneficiation of coal using ultrafine magnetite particles as a pseudo-fluid medium. In this process, the coal particle gains additional weight due to coating on its surface and deposition at dead zone area by fine magnetite particles.Hence, the effective density of coal particle increases and the position of coal particle changes accordingly. In this work, an attempt was made to predict the position of coal particle in non-bubbling condition dense medium fluidized bed system. Coal particles of different shape such as cubical, rectangular prism,spherical and triangular prism with different projected area and density were used. The results show that the position of coal particle in air dense medium fluidized bed follows descending order with respect to the increase of density, projected area of coal particle and different shapes(i.e., triangular prism, cubical,rectangular prism and spherical). Empirical mathematical correlations were developed to predict the position of coal particle.
基金Supported by the National Natural Science Foundation of China (No. 60677040)
文摘This paper presents a robust object tracking approach via a spatially constrained colour model. Local image patches of the object and spatial relation between these patches are informative and stable during object tracking. So, we propose to partition an object into patches and develop a Spatially Constrained Colour Model (SCCM) by combining the colour distributions and spatial configuration of these patches. The likelihood of the candidate object is given by estimating the confidences of the pixels in the candidate object region. The appearance model is learnt from the first frame and the tracking is carried out by particle filter. The experimental results show that the proposed tracking approach can accurately track the object with scale changes, pose variance and partial occlusion.
基金partially supported by the Army Research Office,the National Science Foundation,Willow Garagethe Seed Funding Programme for Basic Research at the University of Hong Kong
文摘The configuration space is a fundamental concept that is widely used in algorithmic robotics. Many applications in robotics, computer-aided design, and related areas can be reduced to computational problems in terms of configuration spaces. In this paper, we survey some of our recent work on solving two important challenges related to configuration spaces: ~ how to efficiently compute an approximate representation of high-dimensional configuration spaces; and how to efficiently perform geometric proximity and motion planning queries (n high-dimensional configuration spaces. We present new configuration space construction algorithms based on machine learning and geometric approximation techniques. These algorithms perform collision queries on many configuration samples. The collision query results are used to compute an approximate representation for the configuration space, which quickly converges to the exact configuration space. We also present parallel GPU-based algorithms to accelerate the performance of optimization and search computations in configuration spaces. In particular, we design efficient GPU-based parallel k-nearest neighbor and parallel collision detection algorithms and use these algorithms to accelerate motion planning.
基金This research is partly supported by the Hunan Provincial Natural Science Foundtion of China and Hunan Provincial Education Foundation of China 02B021
文摘This paper presents a trust region algorithm with null space technique fornonlinear equality constrained optimization. Considering in the null space methods that,the convergent rate of range space step is faster than the null space step for the most cases,the proposed algorithm computes null steps more often than range space step. Moreover,the new algorithm is based on the reduced Hessian SQP method. Global convergence ofthe proposed algorithm is proved. The effectiveness of the method is demonstrated bysome numerical examples.