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
The movement of the wood skidding means on the natural ground causes damages in the soil and in the remaining stand, the size of which depends on the kind, the resistance and the soil conditions, from the size and mov...The movement of the wood skidding means on the natural ground causes damages in the soil and in the remaining stand, the size of which depends on the kind, the resistance and the soil conditions, from the size and movements frequency on the machines as well as from the length of the skidding wood. This study was carried out in a productive forest of Greece, the resistance of the soil in connection with the moisture and the category of the native stone, the pressure that tires of tractors exert in the soil, are estimated. It also estimated the percentage of the trees in the remaining stand which suffer damages from the movement of various means. The above means are used for the skidding of wood of different lengths. According to the results of the research some measures are suggested so as to decrease the damages, which are caused in the soil and in the remaining stand.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The movement of the wood skidding means on the natural ground causes damages in the soil and in the remaining stand, the size of which depends on the kind, the resistance and the soil conditions, from the size and movements frequency on the machines as well as from the length of the skidding wood. This study was carried out in a productive forest of Greece, the resistance of the soil in connection with the moisture and the category of the native stone, the pressure that tires of tractors exert in the soil, are estimated. It also estimated the percentage of the trees in the remaining stand which suffer damages from the movement of various means. The above means are used for the skidding of wood of different lengths. According to the results of the research some measures are suggested so as to decrease the damages, which are caused in the soil and in the remaining stand.
