In order to develop an automated segmentation system for Computed Tomography （CT） brain images, a new approach which consists of several unsupervised segmcotation techniques was introduced. The system segments the C...In order to develop an automated segmentation system for Computed Tomography （CT） brain images, a new approach which consists of several unsupervised segmcotation techniques was introduced. The system segments the CT brain images into three partitions, i. e., abnormalities, cerebrospinal fluid （CSF）, and brain matter. Our approach consists of two phase-segmentation methods. In the first phase segmentation, k-means and fuzzy cmeans （FCM） methods were implemented to segment and transform the images into the binary images. Based on the connected component in binary images, a decision tree was employed for the annotation of normal or abnormal regions. In the second phase segmentation, the modified FCM with population-diameter independent （PDI） segmentation was applied to segment the images into CSF and brain matter. The experimental results have shown that our proposed system is feasible and yield satisfactory results.展开更多
The emergence of third generation mobile system (3G) makes video transmission in wireless environment possible, and the latest 3GPP/3GPP2 standards require 3G terminals support H.264/AVC. Due to high packet loss rate ...The emergence of third generation mobile system (3G) makes video transmission in wireless environment possible, and the latest 3GPP/3GPP2 standards require 3G terminals support H.264/AVC. Due to high packet loss rate in wireless envi- ronment, error resilience for 3G terminals is necessary. Moreover, because of the hardware restrictions, 3G mobile terminals support only part of H.264/AVC error resilience tool. This paper analyzes various error resilience tools and their functions, and presents 2 error resilience strategies for 3G mobile streaming video services and mobile conversational services. Performances of the proposed error resilience strategies were tested using off-line common test conditions. Experiments showed that the proposed error resilience strategies can yield reasonably satisfactory results.展开更多
X2CrNiMoN25-7-3 duplex stainless steel is suitable for chloride-containing environments such as seawater because it has excellent pitting corrosion resistance. Duplex stainless cast steel is often used to accommodate ...X2CrNiMoN25-7-3 duplex stainless steel is suitable for chloride-containing environments such as seawater because it has excellent pitting corrosion resistance. Duplex stainless cast steel is often used to accommodate the complexity of part geometry at joints. However, machining after casting is indispensable. This study evaluated the cutting characteristics of stainless cast steel. Adhesion of the cutting edge was weak at high cutting speeds, but tool wear was large. Diffusion and reactions between the work-pieces and the tool edge were investigated. Slight inter-diffusion and a reaction phase were observed, but the bond-ability was low.展开更多
The use of batteries in UAVs （unmanned aerial vehicles） has become common due to some advantages in comparison with internal combustion engines such as weight reduction and better power control. However, in these ve...The use of batteries in UAVs （unmanned aerial vehicles） has become common due to some advantages in comparison with internal combustion engines such as weight reduction and better power control. However, in these vehicles it is critical to monitor the RUL （remaining useful life） of the batteries. This information can be used, for instance, as a decision support tool to define which missions could be assigned to the UAV until the next battery recharge. This work presents a methodology to predict the RUL of Li-Po （Lithium-Polymer） batteries. The approach uses an extended Kalman filter and an exponential model for the degradation evolution. The proposed methodology uses time series of battery terminal voltages, assuming that the discharge occurs under a constant current condition. Different discharge current levels were considered.The results showed that the proposed methodology provides good results, despite its simplicity.展开更多
In a flank array on an unmanned underwater vehicle （UUV）, self-generated noise which has broadband and colored spectrum property in frequency and spatial domain is the main factor affecting the performance of weak s...In a flank array on an unmanned underwater vehicle （UUV）, self-generated noise which has broadband and colored spectrum property in frequency and spatial domain is the main factor affecting the performance of weak signal detection, so the technique of adaptive noise cancellation （ANC） as well as physical denoising and active noise cancellation are often used in practice. Because ANC is based on correlations, improvements in performance come from better correlation between reference signals and primary signals. Taking full advantage of the characteristics of flank arrays and the characteristics of information obtained from hydrophones, a new method for reference signal acquisition for adaptive noise cancellation is proposed, in which the multi-channel reference signals are obtained by accurate delaying for a given direction of arrival （DOA） and differencing between adjacent outputs of array elements. The validity of the proposed method was verified through system modeling simulations and lake experiments which showed good performance with little additional computational burden.展开更多
Thermal neutron radiography is a useful complementary tool of the other non-destructive testing methods for the hydrogenous materials and heavy metal subassembly.By the use of MC method program and the thermal neutron...Thermal neutron radiography is a useful complementary tool of the other non-destructive testing methods for the hydrogenous materials and heavy metal subassembly.By the use of MC method program and the thermal neutron digital radiography facility at SPRR-300 reactor,the simulation and experimental study of the thermal neutron tomography has been developed.Its method and result has been introduced and analyzed.展开更多
The research was conducted to develop a robot that can navigate a paddy in between rows or hills which were transplanted by the machine transplanter with equal distance. An initial prototype robotic battery-type weede...The research was conducted to develop a robot that can navigate a paddy in between rows or hills which were transplanted by the machine transplanter with equal distance. An initial prototype robotic battery-type weeder was manufactured and tested to navigate and control weeds in rice paddy fields, but a speed was so slow, and thus second engine-type prototype was developed. A working acreage for weed control has been attained at and up to 0.8 ha/day. Small and young weed seedlings were uprooted and destroyed by passive devices in between rows as well as hills. This robot was smoothly navigated in between rows on behalf of the guidance under camera and sensor systems and control weeds with mechanical by the use of implements such as passive rotary weeders and then weeds would be cut and buried into the soils. Also muddy water was generated during operation which was none penetrated by light for weed germination to occur. The authors concluded that the robotic was an effective alternative implement to control weeds in lowland rice paddy as long as this tool was systematically introduced into the rice fields at three time intervals, viz. 15-20 days, 25-30days, and 35-40 days after transplanting of rice seedlings.展开更多
文摘In order to develop an automated segmentation system for Computed Tomography （CT） brain images, a new approach which consists of several unsupervised segmcotation techniques was introduced. The system segments the CT brain images into three partitions, i. e., abnormalities, cerebrospinal fluid （CSF）, and brain matter. Our approach consists of two phase-segmentation methods. In the first phase segmentation, k-means and fuzzy cmeans （FCM） methods were implemented to segment and transform the images into the binary images. Based on the connected component in binary images, a decision tree was employed for the annotation of normal or abnormal regions. In the second phase segmentation, the modified FCM with population-diameter independent （PDI） segmentation was applied to segment the images into CSF and brain matter. The experimental results have shown that our proposed system is feasible and yield satisfactory results.
基金Project supported by the National Natural Science Foundation of China (Nos. 60473106 and 60333010), China Ministry of Education(No. 20030335064), and China Ministry of Science and Technology(No. 2003AA4Z1020)
文摘The emergence of third generation mobile system (3G) makes video transmission in wireless environment possible, and the latest 3GPP/3GPP2 standards require 3G terminals support H.264/AVC. Due to high packet loss rate in wireless envi- ronment, error resilience for 3G terminals is necessary. Moreover, because of the hardware restrictions, 3G mobile terminals support only part of H.264/AVC error resilience tool. This paper analyzes various error resilience tools and their functions, and presents 2 error resilience strategies for 3G mobile streaming video services and mobile conversational services. Performances of the proposed error resilience strategies were tested using off-line common test conditions. Experiments showed that the proposed error resilience strategies can yield reasonably satisfactory results.
文摘X2CrNiMoN25-7-3 duplex stainless steel is suitable for chloride-containing environments such as seawater because it has excellent pitting corrosion resistance. Duplex stainless cast steel is often used to accommodate the complexity of part geometry at joints. However, machining after casting is indispensable. This study evaluated the cutting characteristics of stainless cast steel. Adhesion of the cutting edge was weak at high cutting speeds, but tool wear was large. Diffusion and reactions between the work-pieces and the tool edge were investigated. Slight inter-diffusion and a reaction phase were observed, but the bond-ability was low.
文摘The use of batteries in UAVs （unmanned aerial vehicles） has become common due to some advantages in comparison with internal combustion engines such as weight reduction and better power control. However, in these vehicles it is critical to monitor the RUL （remaining useful life） of the batteries. This information can be used, for instance, as a decision support tool to define which missions could be assigned to the UAV until the next battery recharge. This work presents a methodology to predict the RUL of Li-Po （Lithium-Polymer） batteries. The approach uses an extended Kalman filter and an exponential model for the degradation evolution. The proposed methodology uses time series of battery terminal voltages, assuming that the discharge occurs under a constant current condition. Different discharge current levels were considered.The results showed that the proposed methodology provides good results, despite its simplicity.
基金the National Natural Science Foundation of China under Grant No.60572098
文摘In a flank array on an unmanned underwater vehicle （UUV）, self-generated noise which has broadband and colored spectrum property in frequency and spatial domain is the main factor affecting the performance of weak signal detection, so the technique of adaptive noise cancellation （ANC） as well as physical denoising and active noise cancellation are often used in practice. Because ANC is based on correlations, improvements in performance come from better correlation between reference signals and primary signals. Taking full advantage of the characteristics of flank arrays and the characteristics of information obtained from hydrophones, a new method for reference signal acquisition for adaptive noise cancellation is proposed, in which the multi-channel reference signals are obtained by accurate delaying for a given direction of arrival （DOA） and differencing between adjacent outputs of array elements. The validity of the proposed method was verified through system modeling simulations and lake experiments which showed good performance with little additional computational burden.
基金Supported by the development fund of Science and Technology of China Academy of Engineering Physics.The project number:250
文摘Thermal neutron radiography is a useful complementary tool of the other non-destructive testing methods for the hydrogenous materials and heavy metal subassembly.By the use of MC method program and the thermal neutron digital radiography facility at SPRR-300 reactor,the simulation and experimental study of the thermal neutron tomography has been developed.Its method and result has been introduced and analyzed.
文摘The research was conducted to develop a robot that can navigate a paddy in between rows or hills which were transplanted by the machine transplanter with equal distance. An initial prototype robotic battery-type weeder was manufactured and tested to navigate and control weeds in rice paddy fields, but a speed was so slow, and thus second engine-type prototype was developed. A working acreage for weed control has been attained at and up to 0.8 ha/day. Small and young weed seedlings were uprooted and destroyed by passive devices in between rows as well as hills. This robot was smoothly navigated in between rows on behalf of the guidance under camera and sensor systems and control weeds with mechanical by the use of implements such as passive rotary weeders and then weeds would be cut and buried into the soils. Also muddy water was generated during operation which was none penetrated by light for weed germination to occur. The authors concluded that the robotic was an effective alternative implement to control weeds in lowland rice paddy as long as this tool was systematically introduced into the rice fields at three time intervals, viz. 15-20 days, 25-30days, and 35-40 days after transplanting of rice seedlings.
