This research focuses on the home health care optimization problem that involves staff routing and scheduling problems.The considered problem is an extension of multiple travelling salesman problem.It consists of find...This research focuses on the home health care optimization problem that involves staff routing and scheduling problems.The considered problem is an extension of multiple travelling salesman problem.It consists of finding the shortest path for a set of caregivers visiting a set of patients at their homes in order to perform various tasks during a given horizon.Thus,a mixed-integer linear programming model is proposed to minimize the overall service time performed by all caregivers while respecting the workload balancing constraint.Nevertheless,when the time horizon become large,practical-sized instances become very difficult to solve in a reasonable computational time.Therefore,a new Learning Genetic Algorithm for mTSP(LGA-mTSP)is proposed to solve the problem.LGA-mTSP is composed of a new genetic algorithm for mTSP,combined with a learning approach,called learning curves.Learning refers to that caregivers’productivity increases as they gain more experience.Learning curves approach is considered as a way to save time and costs.Simulation results show the efficiency of the proposed approach and the impact of learning curve strategy to reduce service times.展开更多
In this scientific paper, a complete field of research will be presented, with a detailed dendroclimatology of work, with final results, and conclusions. The research area is named as: “ROGOT”, and within the Forest...In this scientific paper, a complete field of research will be presented, with a detailed dendroclimatology of work, with final results, and conclusions. The research area is named as: “ROGOT”, and within the Forestry Office “Kragujevac” (Serbia), one of the holdings of J.P. Serbia-Forest. An oak tree (Quercus robur Lat.) will be analyzed, and this 30-tree will be arranged in three experimental fields. It should be emphasized that in each experimental field, 5 trees of generative, and 5 trees of deciduous origin will be analyzed, (10 trees per field, total of 30 trees) in order to exclude the genetic basis of variability. Luznjak’s forests are in a dense garden unit of approximate age close to 80 years, which is a good starting point for dendroclimate analysis. The work also analyzes the density of wood, and it has been proven that the density of wood of oak varies, depending on the climate change. Finally, the most appropriate statistical data processing is done. In the end, it was concluded that the research was successful, and that oak (Quercus robur Lat.) was proved to be an excellent indicator of climate change. Climate change is a very important topic in the world today.展开更多
Purpose–The purpose of this paper is to deal with the stabilization of the continuous-time TakagiSugeno(TS)fuzzy models by using their discretized models.Design/methodology/approach–In this case,a discrete model is...Purpose–The purpose of this paper is to deal with the stabilization of the continuous-time TakagiSugeno(TS)fuzzy models by using their discretized models.Design/methodology/approach–In this case,a discrete model is obtained from the discretization of the continuous TS fuzzy model.The gains obtained from a non-parallel distributed compensation controller ensuring the stabilization of the discrete model are used to check if the discrete control law used in the continuous time without any zero-order hold can stabilize the continuous TS model.Findings–This method is compared to another published method.Originality/value–Therefore,the originality of this paper consists in the fusion of the two continuous and discrete cases to obtain new stabilization conditions in the continuous case.Simulation examples show the interest of the proposed approach.展开更多
Purpose–The purpose of this paper is to deal with the stabilization of the continuous Takagi Sugeno(TS)fuzzy models using their discretized forms based on the decay rate performance approach.Design/methodology/appro...Purpose–The purpose of this paper is to deal with the stabilization of the continuous Takagi Sugeno(TS)fuzzy models using their discretized forms based on the decay rate performance approach.Design/methodology/approach–This approach is structured as follows:first,a discrete model is obtained from the discretization of the continuous TS fuzzy model.The discretized model is obtained from the Euler approximation method which is used for several orders.Second,based on the decay rate stabilization conditions,the gains of a non-PDC control law ensuring the stabilization of the discrete model are determined.Third by keeping the values of the gains,the authors determine the values of the performance criterion and the authors check by simulation the stability of the continuous TS fuzzy models through the zero order hold.Findings–The proposed idea lead to compare the performance continuous stability results with the literature.The comparison is,also,taken between the quadratic and non-quadratic cases.Originality/value–Therefore,the originality of this paper consists in the improvement of the continuous fuzzy models by using their discretized models.In this case,the effect of the discretization step on the performances of the continuous TS fuzzy models is studied.The usefulness of this approach is shown through two examples.展开更多
文摘This research focuses on the home health care optimization problem that involves staff routing and scheduling problems.The considered problem is an extension of multiple travelling salesman problem.It consists of finding the shortest path for a set of caregivers visiting a set of patients at their homes in order to perform various tasks during a given horizon.Thus,a mixed-integer linear programming model is proposed to minimize the overall service time performed by all caregivers while respecting the workload balancing constraint.Nevertheless,when the time horizon become large,practical-sized instances become very difficult to solve in a reasonable computational time.Therefore,a new Learning Genetic Algorithm for mTSP(LGA-mTSP)is proposed to solve the problem.LGA-mTSP is composed of a new genetic algorithm for mTSP,combined with a learning approach,called learning curves.Learning refers to that caregivers’productivity increases as they gain more experience.Learning curves approach is considered as a way to save time and costs.Simulation results show the efficiency of the proposed approach and the impact of learning curve strategy to reduce service times.
文摘In this scientific paper, a complete field of research will be presented, with a detailed dendroclimatology of work, with final results, and conclusions. The research area is named as: “ROGOT”, and within the Forestry Office “Kragujevac” (Serbia), one of the holdings of J.P. Serbia-Forest. An oak tree (Quercus robur Lat.) will be analyzed, and this 30-tree will be arranged in three experimental fields. It should be emphasized that in each experimental field, 5 trees of generative, and 5 trees of deciduous origin will be analyzed, (10 trees per field, total of 30 trees) in order to exclude the genetic basis of variability. Luznjak’s forests are in a dense garden unit of approximate age close to 80 years, which is a good starting point for dendroclimate analysis. The work also analyzes the density of wood, and it has been proven that the density of wood of oak varies, depending on the climate change. Finally, the most appropriate statistical data processing is done. In the end, it was concluded that the research was successful, and that oak (Quercus robur Lat.) was proved to be an excellent indicator of climate change. Climate change is a very important topic in the world today.
文摘Purpose–The purpose of this paper is to deal with the stabilization of the continuous-time TakagiSugeno(TS)fuzzy models by using their discretized models.Design/methodology/approach–In this case,a discrete model is obtained from the discretization of the continuous TS fuzzy model.The gains obtained from a non-parallel distributed compensation controller ensuring the stabilization of the discrete model are used to check if the discrete control law used in the continuous time without any zero-order hold can stabilize the continuous TS model.Findings–This method is compared to another published method.Originality/value–Therefore,the originality of this paper consists in the fusion of the two continuous and discrete cases to obtain new stabilization conditions in the continuous case.Simulation examples show the interest of the proposed approach.
文摘Purpose–The purpose of this paper is to deal with the stabilization of the continuous Takagi Sugeno(TS)fuzzy models using their discretized forms based on the decay rate performance approach.Design/methodology/approach–This approach is structured as follows:first,a discrete model is obtained from the discretization of the continuous TS fuzzy model.The discretized model is obtained from the Euler approximation method which is used for several orders.Second,based on the decay rate stabilization conditions,the gains of a non-PDC control law ensuring the stabilization of the discrete model are determined.Third by keeping the values of the gains,the authors determine the values of the performance criterion and the authors check by simulation the stability of the continuous TS fuzzy models through the zero order hold.Findings–The proposed idea lead to compare the performance continuous stability results with the literature.The comparison is,also,taken between the quadratic and non-quadratic cases.Originality/value–Therefore,the originality of this paper consists in the improvement of the continuous fuzzy models by using their discretized models.In this case,the effect of the discretization step on the performances of the continuous TS fuzzy models is studied.The usefulness of this approach is shown through two examples.
