Forest wildfires pose significant and growing threats to human safety, wildlife habitat, regional economies and global climate change. It is crucial that forest fires be subject to timely and accurate monitoring by fo...Forest wildfires pose significant and growing threats to human safety, wildlife habitat, regional economies and global climate change. It is crucial that forest fires be subject to timely and accurate monitoring by forest fire managers and other stake-holders. Measurement by spaceborne equipment has become a practical and appealing method to monitor the occurrence and development of forest wildfires. Here we present an overview of the principles and case studies of forest fire monitoring（FFM） with satelliteand drone-mounted infrared remote sensing（IRRS）. This review includes four types of FFM-relevant IRRS algorithms： bi-spectral methods, fixed threshold methods, spatial contextual methods, and multi-temporal methods. The spatial contextual methods are presented in detail since they can be applied easily with commonly available satellite IRRS data, including MODIS, VIIRS, and Landsat 8 OLI. This review also evaluates typical cases of FFM using NOAAAVHRR, EOS-MODIS, S-NPP VIIRS, Landsat 8 OLI,MSG-SEVIRI, and drone infrared data. To better implement IRRS applications in FFM, it is important to develop accurate forest masks, carry out systematic comparative studies of various forest fire detection systems（known as forest fire products）, and improve methods for assessing the accuracy of forest fire detection. Medium-resolution IRRS data are effective for landscape-scale FFM, and the VIIRS 375 m contextual algorithm and RST-FIRES algorithm are helpful for closely tracking forest fires（including small and shortlived fires） and forest-fire early warning.展开更多
The topic investigated competition in marketing as a survival yardstick for small and medium enterprises （SMEs） in Nigeria. The objectives addressed by this study were： （1） identifying different types and intensi...The topic investigated competition in marketing as a survival yardstick for small and medium enterprises （SMEs） in Nigeria. The objectives addressed by this study were： （1） identifying different types and intensity of competition that SMEs are exposed to along the life-cycle portfolio in Nigeria; （2） quantifying the strength of SMEs vis-a-vis some foreign enterprises in terms of market competition; and （3） proffering solutions on how best they could match competitively these foreign enterprises. Relevant models and theories were employed in literature to evolve detailed analysis of issues relating to the variables used in terms of competition in marketing and survival of juice-producing SMEs. Two hypotheses were investigated through the survey of 20 prominent Ikeja based SMEs using Cluster sampling, 5-points Likert summated rating scale was adopted, while Yard＇s formula with 95% confidence level and 5% error tolerance was used. Alternative form validity of the instrument was measured at 0.63 while its reliability was measured at Cronbach＇s alpha of 0.70. Pearson＇s product-moment correlation was used in testing hypothesis 1 while standard multiple regressions were used to test hypothesis 2. Findings revealed that there was strong relationship between survival of juice-producing SMEs with forms of competition on a firm＇s life-cycle; while competition had positive effects on survival components for the enterprises. It was concluded that since competition subsists in any firm＇s life-cycle, strategies to support operations for survival must be adopted. It was recommended that operators of SMEs have to monitor and manage competition as it affects their businesses positively and/or negatively.展开更多
基金financially supported by The National Natural Science Foundation of China[41471366]The Mc Intire-Stennis Cooperative Forestry Research Program
文摘Forest wildfires pose significant and growing threats to human safety, wildlife habitat, regional economies and global climate change. It is crucial that forest fires be subject to timely and accurate monitoring by forest fire managers and other stake-holders. Measurement by spaceborne equipment has become a practical and appealing method to monitor the occurrence and development of forest wildfires. Here we present an overview of the principles and case studies of forest fire monitoring（FFM） with satelliteand drone-mounted infrared remote sensing（IRRS）. This review includes four types of FFM-relevant IRRS algorithms： bi-spectral methods, fixed threshold methods, spatial contextual methods, and multi-temporal methods. The spatial contextual methods are presented in detail since they can be applied easily with commonly available satellite IRRS data, including MODIS, VIIRS, and Landsat 8 OLI. This review also evaluates typical cases of FFM using NOAAAVHRR, EOS-MODIS, S-NPP VIIRS, Landsat 8 OLI,MSG-SEVIRI, and drone infrared data. To better implement IRRS applications in FFM, it is important to develop accurate forest masks, carry out systematic comparative studies of various forest fire detection systems（known as forest fire products）, and improve methods for assessing the accuracy of forest fire detection. Medium-resolution IRRS data are effective for landscape-scale FFM, and the VIIRS 375 m contextual algorithm and RST-FIRES algorithm are helpful for closely tracking forest fires（including small and shortlived fires） and forest-fire early warning.
文摘The topic investigated competition in marketing as a survival yardstick for small and medium enterprises （SMEs） in Nigeria. The objectives addressed by this study were： （1） identifying different types and intensity of competition that SMEs are exposed to along the life-cycle portfolio in Nigeria; （2） quantifying the strength of SMEs vis-a-vis some foreign enterprises in terms of market competition; and （3） proffering solutions on how best they could match competitively these foreign enterprises. Relevant models and theories were employed in literature to evolve detailed analysis of issues relating to the variables used in terms of competition in marketing and survival of juice-producing SMEs. Two hypotheses were investigated through the survey of 20 prominent Ikeja based SMEs using Cluster sampling, 5-points Likert summated rating scale was adopted, while Yard＇s formula with 95% confidence level and 5% error tolerance was used. Alternative form validity of the instrument was measured at 0.63 while its reliability was measured at Cronbach＇s alpha of 0.70. Pearson＇s product-moment correlation was used in testing hypothesis 1 while standard multiple regressions were used to test hypothesis 2. Findings revealed that there was strong relationship between survival of juice-producing SMEs with forms of competition on a firm＇s life-cycle; while competition had positive effects on survival components for the enterprises. It was concluded that since competition subsists in any firm＇s life-cycle, strategies to support operations for survival must be adopted. It was recommended that operators of SMEs have to monitor and manage competition as it affects their businesses positively and/or negatively.
