Supervisory Control and Data Acquisition （SCADA） is used broadly to portray control and management solutions in a wide range of industries. SCADA system failure may lead to disastrous consequences since the health a...Supervisory Control and Data Acquisition （SCADA） is used broadly to portray control and management solutions in a wide range of industries. SCADA system failure may lead to disastrous consequences since the health and the safety of the public as the economic viability of the community it serves depends on it. After its introduction in DPDC over a decade ago, the SCADA system hardly had any performance upgradation. Currently, the microwave link in SCADA Communication is observing problems that are rendering the entire structure obsolete. This paper revises the possibility to implement a new communication technology and proposes Free Space Optical （FSO） communication to enhance SCADA system reliability. FSO refers to the transmission of modulated visible or infrared （IR） beams through the air to obtain optical communication. Like optical fiber, FSO also uses lasers to transmit data, but instead of enclosing the data stream in a glass fiber, the data is transmitted through the air. It is a secure, cost-effective alternative to other wireless connectivity options.展开更多
Extreme weather and climate events are likely to cause disastrous consequences for agriculture and food security. This study investigated the impacts of drought in year 2012 on corn yield in the United States Corn Bel...Extreme weather and climate events are likely to cause disastrous consequences for agriculture and food security. This study investigated the impacts of drought in year 2012 on corn yield in the United States Corn Belt by integrating county-level crop yield data from the USDA NASS Quick Stats database and precipitation data from the NCDC GHCN-Daily database. It is found that precipitation over an 8-week period in corn growth stages is critical for corn yield, the logarithm of precipitation during the period explained 55% of corn yield variation. The results indicated the importance of water supply in corn silking stage, and provided an approach to assess the impacts of drought on corn yield quantitatively.展开更多
文摘Supervisory Control and Data Acquisition （SCADA） is used broadly to portray control and management solutions in a wide range of industries. SCADA system failure may lead to disastrous consequences since the health and the safety of the public as the economic viability of the community it serves depends on it. After its introduction in DPDC over a decade ago, the SCADA system hardly had any performance upgradation. Currently, the microwave link in SCADA Communication is observing problems that are rendering the entire structure obsolete. This paper revises the possibility to implement a new communication technology and proposes Free Space Optical （FSO） communication to enhance SCADA system reliability. FSO refers to the transmission of modulated visible or infrared （IR） beams through the air to obtain optical communication. Like optical fiber, FSO also uses lasers to transmit data, but instead of enclosing the data stream in a glass fiber, the data is transmitted through the air. It is a secure, cost-effective alternative to other wireless connectivity options.
文摘Extreme weather and climate events are likely to cause disastrous consequences for agriculture and food security. This study investigated the impacts of drought in year 2012 on corn yield in the United States Corn Belt by integrating county-level crop yield data from the USDA NASS Quick Stats database and precipitation data from the NCDC GHCN-Daily database. It is found that precipitation over an 8-week period in corn growth stages is critical for corn yield, the logarithm of precipitation during the period explained 55% of corn yield variation. The results indicated the importance of water supply in corn silking stage, and provided an approach to assess the impacts of drought on corn yield quantitatively.
