The force model during needle insertion into soft tissue is important for accurate percutaneous intervention.In this paper,a force model for needle insertion into a tissue- equivalent material is presented and a serie...The force model during needle insertion into soft tissue is important for accurate percutaneous intervention.In this paper,a force model for needle insertion into a tissue- equivalent material is presented and a series of experiments are conducted to acquire data from needle soft- tissue interaction process.In order to build a more accurate insertion force model,the interaction force between a surgical needle and soft tissue is divided into three parts:stiffness force,friction force,and cutting force.The stiffness force is modeled on the basis of contact mechanics model.The friction force model is presented using a modified Winkler' s foundation model.The cutting force is viewed as a constant depending on a given tissue.The proposed models in the paper are established on the basis of the mechanical properties and geometric parameters of the needle and soft tissue.The experimental results illustrate that the force models are capable of predicting the needle-tissue interaction force.The force models of needle insertion can provide real-time haptic feedback for robot-assisted procedures,thereby improving the accuracy and safety of surgery.展开更多
The hypothesis ＂happy productive worker＂ states that happy employees, whose needs are satisfied in their workplace, have greater performance than unhappy employees. Therefore, the purpose of this research is to exam...The hypothesis ＂happy productive worker＂ states that happy employees, whose needs are satisfied in their workplace, have greater performance than unhappy employees. Therefore, the purpose of this research is to examine empirically the effects that job satisfaction and well-being at work generate on the individual job performance, investigating the moderating role that the components of the organizational structure play in this relationship. To achieve the main objective, some secondary objectives were proposed： （1） test the predictive effect of well-being, satisfaction, personal, and professional variables on individual performance; and （2） test the moderating effect of the components of the organizational structure in the relationship among well-being, satisfaction, and individual job performance. This research originates of a consolidated statement for the business society, but very few empirical studies. This way, the hypothesis consisted in the components of the organizational structure will positively enhance the relationship among well-being at work, job satisfaction, and individual job performance. The final sample consisted of 134 participants, of a clinical laboratory and of federal court of justice. For the development of the questionnaire, four instruments were used; one for each construct. The proposal has four relationship variables and the statistical procedure used to test this hypothesis was multiple linear regressions. Considering the hypothetical theoretical model presented, personal and professional variables are predictors of job performance; thus, these variables were also included as independent variables. The results of the regression model showed that the variables ＂age＂, ＂well-being at work＂, ＂job satisfaction＂, and ＂components of organizational structure＂ are responsible for explaining 64% of the variance of the variable criteria and individual job performance The moderating role of the variable ＂components of organizational structure＂ was also observed, because its inclusion increased the explained variance of the dependent variable. After all the discussions developed, the two main contributions appear： （1） the predictive effect of well-being at work in relation to performance and （2） identifying the moderating effect of the components of the organizational structure.展开更多
In this paper, transmission power control problem for uplink LTE network is investigated and a new autonomic uplink power control scheme was proposed based on utility function, which is a self- organized algorithm. Th...In this paper, transmission power control problem for uplink LTE network is investigated and a new autonomic uplink power control scheme was proposed based on utility function, which is a self- organized algorithm. The whole approach is based on the economic concept named utility function. Then a self-organized algorithm is distributed in each mobile users to control the transmission power and to maximize the transmission utility. The proposed scheme is solved through the Lagrange multiplier technique. It is proved that the utility function based algorithm optimal power level can be model. is applicable and the achieved based on our展开更多
基金Supported by the National Natural Science Foundation of China(No.51175373)New Century Educational Talents Plan of Chinese Education Ministry(No.NCET-10-0625)+1 种基金Key Technology and Development Program of Tianjin Municipal Science and Technology Commission(No.12ZCDZSY10600)Tianjin Key Laboratory of High Speed Cutting&Precision Machining(TUTE)(2013120024001167)
文摘The force model during needle insertion into soft tissue is important for accurate percutaneous intervention.In this paper,a force model for needle insertion into a tissue- equivalent material is presented and a series of experiments are conducted to acquire data from needle soft- tissue interaction process.In order to build a more accurate insertion force model,the interaction force between a surgical needle and soft tissue is divided into three parts:stiffness force,friction force,and cutting force.The stiffness force is modeled on the basis of contact mechanics model.The friction force model is presented using a modified Winkler' s foundation model.The cutting force is viewed as a constant depending on a given tissue.The proposed models in the paper are established on the basis of the mechanical properties and geometric parameters of the needle and soft tissue.The experimental results illustrate that the force models are capable of predicting the needle-tissue interaction force.The force models of needle insertion can provide real-time haptic feedback for robot-assisted procedures,thereby improving the accuracy and safety of surgery.
文摘The hypothesis ＂happy productive worker＂ states that happy employees, whose needs are satisfied in their workplace, have greater performance than unhappy employees. Therefore, the purpose of this research is to examine empirically the effects that job satisfaction and well-being at work generate on the individual job performance, investigating the moderating role that the components of the organizational structure play in this relationship. To achieve the main objective, some secondary objectives were proposed： （1） test the predictive effect of well-being, satisfaction, personal, and professional variables on individual performance; and （2） test the moderating effect of the components of the organizational structure in the relationship among well-being, satisfaction, and individual job performance. This research originates of a consolidated statement for the business society, but very few empirical studies. This way, the hypothesis consisted in the components of the organizational structure will positively enhance the relationship among well-being at work, job satisfaction, and individual job performance. The final sample consisted of 134 participants, of a clinical laboratory and of federal court of justice. For the development of the questionnaire, four instruments were used; one for each construct. The proposal has four relationship variables and the statistical procedure used to test this hypothesis was multiple linear regressions. Considering the hypothetical theoretical model presented, personal and professional variables are predictors of job performance; thus, these variables were also included as independent variables. The results of the regression model showed that the variables ＂age＂, ＂well-being at work＂, ＂job satisfaction＂, and ＂components of organizational structure＂ are responsible for explaining 64% of the variance of the variable criteria and individual job performance The moderating role of the variable ＂components of organizational structure＂ was also observed, because its inclusion increased the explained variance of the dependent variable. After all the discussions developed, the two main contributions appear： （1） the predictive effect of well-being at work in relation to performance and （2） identifying the moderating effect of the components of the organizational structure.
文摘In this paper, transmission power control problem for uplink LTE network is investigated and a new autonomic uplink power control scheme was proposed based on utility function, which is a self- organized algorithm. The whole approach is based on the economic concept named utility function. Then a self-organized algorithm is distributed in each mobile users to control the transmission power and to maximize the transmission utility. The proposed scheme is solved through the Lagrange multiplier technique. It is proved that the utility function based algorithm optimal power level can be model. is applicable and the achieved based on our
