Multiple-input multiple-output （MIMO） radar is a new concept with some new characteristics, such as multiple orthogonal waveforms and omnidirectional coverage. Based on Stein＇s lemma, we use relative entropy as a p...Multiple-input multiple-output （MIMO） radar is a new concept with some new characteristics, such as multiple orthogonal waveforms and omnidirectional coverage. Based on Stein＇s lemma, we use relative entropy as a precise and general measure of error exponent to study detection performance for both MIMO radar and phased array radar. And based on derived analytical results, we further study the system configuration problem of Bistatic MIMO radar systems, where transmitters and receivers are located in different positions. Some interesting results are presented. For phased array radar, when the total numbers of transmitters and receivers are fixed, we should always make the number of transmitters equal to the number of receivers. For MIMO radar, we should use a small number of transmitters in low signal noise ratio （SNR） region, and make the number of transmitters equal to the number of receivers in high SNR region. These results are instructive for deployment of bistatic MIMO radar systems in the future.展开更多
Recent years, underground mining method is becoming popular because of its potentially high productivity and efficiency. In this method, a mining machinery; load haul dump(LHD), is used as both an excavator and a tran...Recent years, underground mining method is becoming popular because of its potentially high productivity and efficiency. In this method, a mining machinery; load haul dump(LHD), is used as both an excavator and a transporter of ore. This paper proposes a distributed system that realizes the excavation and transport functions with separated vehicles, an excavator and a transporter. In addition, this research proposes a mining map and configurations suitable for the proposed distributed system. To evaluate the productivity of the proposed system, a simulation environment has been developed. Analysis using the simulator reveals what performance factors of the excavator and the transporter have large impacts on the productivity. Simulation results also demonstrate the difference of potential between LHD system and the distributed system that can be explained based on their functions allocation.展开更多
Core damage accident scenarios are identified for the metal-fueled, sodium-cooled fast reactor （SFR）, KALIMER-600, which is under development at KAERI. A level 1 probabilistic safety assessment （PSA） model is deve...Core damage accident scenarios are identified for the metal-fueled, sodium-cooled fast reactor （SFR）, KALIMER-600, which is under development at KAERI. A level 1 probabilistic safety assessment （PSA） model is developed using the identified accident scenarios and the system fault tree models for the safety systems which are needed to mitigate the accidents. Using the preliminary level 1 PSA models, core damage frequency is estimated for the metal fueled KALIMER-600 conceptual design. Sensitivity studies for various design alternatives of safety systems are performed to find out optimal configurations in point of view of risk minimization.展开更多
New Zealand is well known for export of meat and dairy products from low cost pastoral systems. These farm systems are continually evolving for increased efficiency, in part through the use of metabolic energy modelin...New Zealand is well known for export of meat and dairy products from low cost pastoral systems. These farm systems are continually evolving for increased efficiency, in part through the use of metabolic energy modeling tools by farmers and farm consultants to explore alternative farm system configurations and identify new efficiencies. One recent innovation is the introduction of a herb pasture area, such as plantain. We used metabolic energy modeling to quantify seasonal feed flows in two successive years in a New Zealand hill country farm system, and to analyze the impact of the introduction of an area of plantain. Models employed were a self-built Microsoft Excel spreadsheet and a commercial New Zealand farm systems modeling package, FARMAX.Herbage production, animal performance and financial results for a base farm scenario created from the average of survey data for hill farms in the southern North Island, and the same farm with 10% and 20% of the area in plantain for the years 2010–2011 and 2011–2012 were modeled. The self-built model performed similarly to the commercial model. The system configuration of the base farm stockpiles surplus autumn feed for release to animals in winter and also incorporates flexibility that confers resilience to interannual weather variation through varying dates animals are purchased or sold. The introduction of an area of plantain was predicted to increase herbage production, animal performance and financial returns.The predicted benefit was higher for the year 2010–2011 where a drought occurred in summer than for the following year with higher summer rainfall. This demonstrates the profitability of introducing a plantain area to New Zealand hill farm systems, and suggests plantain will assist to mitigate adverse effects of warmer and drier summer conditions associated with current climate change trends.展开更多
基金Supported in part by the National Natural Science Foundation of China (Grant No. 60602048)aviation science funds of China(Grant No. 20060112118)the National Ministry Foundation of China (Grant No. 20094010040)
文摘Multiple-input multiple-output （MIMO） radar is a new concept with some new characteristics, such as multiple orthogonal waveforms and omnidirectional coverage. Based on Stein＇s lemma, we use relative entropy as a precise and general measure of error exponent to study detection performance for both MIMO radar and phased array radar. And based on derived analytical results, we further study the system configuration problem of Bistatic MIMO radar systems, where transmitters and receivers are located in different positions. Some interesting results are presented. For phased array radar, when the total numbers of transmitters and receivers are fixed, we should always make the number of transmitters equal to the number of receivers. For MIMO radar, we should use a small number of transmitters in low signal noise ratio （SNR） region, and make the number of transmitters equal to the number of receivers in high SNR region. These results are instructive for deployment of bistatic MIMO radar systems in the future.
文摘Recent years, underground mining method is becoming popular because of its potentially high productivity and efficiency. In this method, a mining machinery; load haul dump(LHD), is used as both an excavator and a transporter of ore. This paper proposes a distributed system that realizes the excavation and transport functions with separated vehicles, an excavator and a transporter. In addition, this research proposes a mining map and configurations suitable for the proposed distributed system. To evaluate the productivity of the proposed system, a simulation environment has been developed. Analysis using the simulator reveals what performance factors of the excavator and the transporter have large impacts on the productivity. Simulation results also demonstrate the difference of potential between LHD system and the distributed system that can be explained based on their functions allocation.
文摘Core damage accident scenarios are identified for the metal-fueled, sodium-cooled fast reactor （SFR）, KALIMER-600, which is under development at KAERI. A level 1 probabilistic safety assessment （PSA） model is developed using the identified accident scenarios and the system fault tree models for the safety systems which are needed to mitigate the accidents. Using the preliminary level 1 PSA models, core damage frequency is estimated for the metal fueled KALIMER-600 conceptual design. Sensitivity studies for various design alternatives of safety systems are performed to find out optimal configurations in point of view of risk minimization.
文摘New Zealand is well known for export of meat and dairy products from low cost pastoral systems. These farm systems are continually evolving for increased efficiency, in part through the use of metabolic energy modeling tools by farmers and farm consultants to explore alternative farm system configurations and identify new efficiencies. One recent innovation is the introduction of a herb pasture area, such as plantain. We used metabolic energy modeling to quantify seasonal feed flows in two successive years in a New Zealand hill country farm system, and to analyze the impact of the introduction of an area of plantain. Models employed were a self-built Microsoft Excel spreadsheet and a commercial New Zealand farm systems modeling package, FARMAX.Herbage production, animal performance and financial results for a base farm scenario created from the average of survey data for hill farms in the southern North Island, and the same farm with 10% and 20% of the area in plantain for the years 2010–2011 and 2011–2012 were modeled. The self-built model performed similarly to the commercial model. The system configuration of the base farm stockpiles surplus autumn feed for release to animals in winter and also incorporates flexibility that confers resilience to interannual weather variation through varying dates animals are purchased or sold. The introduction of an area of plantain was predicted to increase herbage production, animal performance and financial returns.The predicted benefit was higher for the year 2010–2011 where a drought occurred in summer than for the following year with higher summer rainfall. This demonstrates the profitability of introducing a plantain area to New Zealand hill farm systems, and suggests plantain will assist to mitigate adverse effects of warmer and drier summer conditions associated with current climate change trends.
