This work studies the problem of control design for linear systems with input saturation.It is well known that integral quadratic constraints(IQC) can be used to describe input saturation and that the use of IQC in an...This work studies the problem of control design for linear systems with input saturation.It is well known that integral quadratic constraints(IQC) can be used to describe input saturation and that the use of IQC in analysis can lead to less conservative performance bound and larger domain of attraction.In this work,it is shown that a class of commonly used IQCs may not help in control synthesis.That is,the use of these IQCs does not enlarge the guaranteed domain of performance for synthesis.展开更多
Agricultural inputs are necessities in a production process just as food is a necessity for human survival. Production comes with the use of inputs. The cultivation of maize in Cameroon is predominantly dominated by s...Agricultural inputs are necessities in a production process just as food is a necessity for human survival. Production comes with the use of inputs. The cultivation of maize in Cameroon is predominantly dominated by smallholder farmers who use traditional methods and face drudgery. The current production level of maize in the country is declining and to meet consumption requirements, huge quantities of the commodity are imported. This study questions the impacts of variable input costs on maize production. Inputs are building blocks of production costs;it is therefore important for maize farmers to be alerted on the effective use of farm inputs in order to obtain higher returns. Data were collected with the use of a structured questionnaire. They were analysed using descriptive statistics and OLS Regression techniques. Results show that on average per hectare, each maize farmer spends USD10.12 on seeds, USD28.90 on fertilizer, USD8.90 on labour, and USD13.28 on herbicides. The regression results show that estimated coefficients of unit costs of fertilizer, herbicides and labour were negative but insignificant while land and hybrid seeds were positive. Input subsidy is recommended as a policy instrument to lower prices paid by farmers.展开更多
Rising labor opportunity cost is one of the most important characteristics of farmers' economic environment in present China,and brings great agricultural land use changes correspondingly.Based on the stratified r...Rising labor opportunity cost is one of the most important characteristics of farmers' economic environment in present China,and brings great agricultural land use changes correspondingly.Based on the stratified random sample of rural households in Sui County,this paper estimates the opportunity cost of farm labors,and then analyzes its effect on farmers' agricultural land use decisions.The findings show that the households with higher labor opportunity cost are more likely to reduce labor intensity and increase labor-saving input in their land use decisions.From the descriptive analysis,we also find these households always prefer grain crop planting,reduce yield-raising input or even rent out their cultivated land.As labor and yield-raising input are two essential positive factors for grain production,continuous declining of labor input and yield-raising input caused by rising labor opportunity cost may influence the grain yield per unit area in the future.展开更多
文摘This work studies the problem of control design for linear systems with input saturation.It is well known that integral quadratic constraints(IQC) can be used to describe input saturation and that the use of IQC in analysis can lead to less conservative performance bound and larger domain of attraction.In this work,it is shown that a class of commonly used IQCs may not help in control synthesis.That is,the use of these IQCs does not enlarge the guaranteed domain of performance for synthesis.
文摘Agricultural inputs are necessities in a production process just as food is a necessity for human survival. Production comes with the use of inputs. The cultivation of maize in Cameroon is predominantly dominated by smallholder farmers who use traditional methods and face drudgery. The current production level of maize in the country is declining and to meet consumption requirements, huge quantities of the commodity are imported. This study questions the impacts of variable input costs on maize production. Inputs are building blocks of production costs;it is therefore important for maize farmers to be alerted on the effective use of farm inputs in order to obtain higher returns. Data were collected with the use of a structured questionnaire. They were analysed using descriptive statistics and OLS Regression techniques. Results show that on average per hectare, each maize farmer spends USD10.12 on seeds, USD28.90 on fertilizer, USD8.90 on labour, and USD13.28 on herbicides. The regression results show that estimated coefficients of unit costs of fertilizer, herbicides and labour were negative but insignificant while land and hybrid seeds were positive. Input subsidy is recommended as a policy instrument to lower prices paid by farmers.
基金Under the auspices of National Science Foundation of China(Grant no.40971062)
文摘Rising labor opportunity cost is one of the most important characteristics of farmers' economic environment in present China,and brings great agricultural land use changes correspondingly.Based on the stratified random sample of rural households in Sui County,this paper estimates the opportunity cost of farm labors,and then analyzes its effect on farmers' agricultural land use decisions.The findings show that the households with higher labor opportunity cost are more likely to reduce labor intensity and increase labor-saving input in their land use decisions.From the descriptive analysis,we also find these households always prefer grain crop planting,reduce yield-raising input or even rent out their cultivated land.As labor and yield-raising input are two essential positive factors for grain production,continuous declining of labor input and yield-raising input caused by rising labor opportunity cost may influence the grain yield per unit area in the future.
