The initial motivation of the lifting technique is to solve the H∞control problems.However,the conventional weighted H∞design does not meet the conditions required by lifting,so the result often leads to a misjudgem...The initial motivation of the lifting technique is to solve the H∞control problems.However,the conventional weighted H∞design does not meet the conditions required by lifting,so the result often leads to a misjudgement of the design.Two conditions required by using the lifting technique are presented based on the basic formulae of the lifting.It is pointed out that only the H∞disturbance attenuation problem with no weighting functions can meet these conditions,hence,the application of the lifting technique is quite limited.展开更多
Deficiencies of the performance-based iterative learning control （ILC） for the non-regular systems are investigated in detail, then a faster control input updating and lifting technique is introduced in the design o...Deficiencies of the performance-based iterative learning control （ILC） for the non-regular systems are investigated in detail, then a faster control input updating and lifting technique is introduced in the design of performance index based ILCs for the partial non-regular systems. Two ldnds of optimal ILCs based on different performance indices are considered. Finally, simulation examples are given to illustrate the feasibility of the proposed learning controls.展开更多
BACKGROUND Among the rapidly developing single-incision laparoscopic cholecystectomy(LC)techniques,transumbilical single-incision LC is increasingly replacing the traditional LC,with advantages of minimal invasion,sli...BACKGROUND Among the rapidly developing single-incision laparoscopic cholecystectomy(LC)techniques,transumbilical single-incision LC is increasingly replacing the traditional LC,with advantages of minimal invasion,slight postoperative pain,faster recovery.Despite the advantages mentioned above,the currently available specialized single-port laparoscopic instruments are hindered by high costs and limited applications,challenging their widespread use in medical facilities.AIM To design a two-point lifting/retracting(TPLR)technique for transumbilical single-port LC(TUSPLC)based on the anatomical features of the Calot's triangle(or cystohepatic triangle)and investigate its surgical feasibility.METHODS The clinical data of 103 patients who underwent TUSPLC utilizing the TPLR technique in the Department of Hepatobiliary Surgery at our hospital between June 2023 and June 2024 were retrospectively analyzed.The patient cohort included 82 cases of cholelithiasis,11 cases of gallbladder polyps,6 cases of concurrent gallstones and polyps,and 4 cases of gallbladder adenomyomatosis.RESULTS All the surgical procedures were conducted using standard laparoscopic instruments.Surgery was successful in 98(95.14%)patients using the TPLR method,which effectively exposed the Calot's triangle during surgery.The operative time ranged from 35 to 70 minutes,with an average of 42.4±26.8 minutes.In 3 cases,an additional operative port was required below the xiphoid process,and 2 cases were converted to conventional three-port LC.No complications such as abdominal pain,fever,bile leakage,hemorrhage,or incisional infection were noted postoperatively.No discernible surgical scars were observed at the 2-week postoperative reexamination.Additionally,a 3-month follow-up period revealed no complications.CONCLUSION The TPLR technique,developed based on the anatomical features of the Calot's triangle,facilitates exposure of the Calot's triangle during surgery.It is a simple,safe,feasible,and cost-effective method,and a promising approach for single-port LC.展开更多
A dual-rate preview control strategy for a type of discrete-time system is proposed based on the theory of multirate control. First, by using the discrete lifting technique, the general dual-rate discrete-time system ...A dual-rate preview control strategy for a type of discrete-time system is proposed based on the theory of multirate control. First, by using the discrete lifting technique, the general dual-rate discrete-time system is converted into a single-rate augmented system. On this basis, the augmented error system is constructed by introducing a first-order difference operator and the previewable reference signal. Then the tracking problem is transformed into a regulator problem of the augmented error system. The optimal preview control law of the augmented error system is obtained by using standard linear quadratic optimal preview control theory, and then the optimal preview controller of the original system is derived. In addition, the necessary and sufficient conditions for the controller are given.Finally, simulation results show the effectiveness of the proposed method.展开更多
In this paper, we investigate spectral method for mixed inhomogeneous boundary value problems in three dimensions. Some results on the three-dimensional Legendre approxima- tion in Jacobi weighted Sobolev space are es...In this paper, we investigate spectral method for mixed inhomogeneous boundary value problems in three dimensions. Some results on the three-dimensional Legendre approxima- tion in Jacobi weighted Sobolev space are established, which improve and generalize the existing results, and play an important role in numerical solutions of partial differential equations. We also develop a lifting technique, with which we could handle mixed inho- mogeneous boundary conditions easily. As examples of applications, spectral schemes are provided for three model problems with mixed inhomogeneous boundary conditions. The spectral accuracy in space of proposed algorithms is proved. Efficient implementations are presented. Numerical results demonstrate their high accuracy, and confirm the theoretical analysis well.展开更多
基金Supported by the Harbin Engineering University Fund for Basic Projects(heuft06041)
文摘The initial motivation of the lifting technique is to solve the H∞control problems.However,the conventional weighted H∞design does not meet the conditions required by lifting,so the result often leads to a misjudgement of the design.Two conditions required by using the lifting technique are presented based on the basic formulae of the lifting.It is pointed out that only the H∞disturbance attenuation problem with no weighting functions can meet these conditions,hence,the application of the lifting technique is quite limited.
基金supported by the National Natural Science Foundation of China (No.60774023)Hunan Provincial Natural Science Foundation (No.06JJ50141)
文摘Deficiencies of the performance-based iterative learning control （ILC） for the non-regular systems are investigated in detail, then a faster control input updating and lifting technique is introduced in the design of performance index based ILCs for the partial non-regular systems. Two ldnds of optimal ILCs based on different performance indices are considered. Finally, simulation examples are given to illustrate the feasibility of the proposed learning controls.
文摘BACKGROUND Among the rapidly developing single-incision laparoscopic cholecystectomy(LC)techniques,transumbilical single-incision LC is increasingly replacing the traditional LC,with advantages of minimal invasion,slight postoperative pain,faster recovery.Despite the advantages mentioned above,the currently available specialized single-port laparoscopic instruments are hindered by high costs and limited applications,challenging their widespread use in medical facilities.AIM To design a two-point lifting/retracting(TPLR)technique for transumbilical single-port LC(TUSPLC)based on the anatomical features of the Calot's triangle(or cystohepatic triangle)and investigate its surgical feasibility.METHODS The clinical data of 103 patients who underwent TUSPLC utilizing the TPLR technique in the Department of Hepatobiliary Surgery at our hospital between June 2023 and June 2024 were retrospectively analyzed.The patient cohort included 82 cases of cholelithiasis,11 cases of gallbladder polyps,6 cases of concurrent gallstones and polyps,and 4 cases of gallbladder adenomyomatosis.RESULTS All the surgical procedures were conducted using standard laparoscopic instruments.Surgery was successful in 98(95.14%)patients using the TPLR method,which effectively exposed the Calot's triangle during surgery.The operative time ranged from 35 to 70 minutes,with an average of 42.4±26.8 minutes.In 3 cases,an additional operative port was required below the xiphoid process,and 2 cases were converted to conventional three-port LC.No complications such as abdominal pain,fever,bile leakage,hemorrhage,or incisional infection were noted postoperatively.No discernible surgical scars were observed at the 2-week postoperative reexamination.Additionally,a 3-month follow-up period revealed no complications.CONCLUSION The TPLR technique,developed based on the anatomical features of the Calot's triangle,facilitates exposure of the Calot's triangle during surgery.It is a simple,safe,feasible,and cost-effective method,and a promising approach for single-port LC.
基金Supported by the National Natural Science Foundation of China(61174209)
文摘A dual-rate preview control strategy for a type of discrete-time system is proposed based on the theory of multirate control. First, by using the discrete lifting technique, the general dual-rate discrete-time system is converted into a single-rate augmented system. On this basis, the augmented error system is constructed by introducing a first-order difference operator and the previewable reference signal. Then the tracking problem is transformed into a regulator problem of the augmented error system. The optimal preview control law of the augmented error system is obtained by using standard linear quadratic optimal preview control theory, and then the optimal preview controller of the original system is derived. In addition, the necessary and sufficient conditions for the controller are given.Finally, simulation results show the effectiveness of the proposed method.
文摘In this paper, we investigate spectral method for mixed inhomogeneous boundary value problems in three dimensions. Some results on the three-dimensional Legendre approxima- tion in Jacobi weighted Sobolev space are established, which improve and generalize the existing results, and play an important role in numerical solutions of partial differential equations. We also develop a lifting technique, with which we could handle mixed inho- mogeneous boundary conditions easily. As examples of applications, spectral schemes are provided for three model problems with mixed inhomogeneous boundary conditions. The spectral accuracy in space of proposed algorithms is proved. Efficient implementations are presented. Numerical results demonstrate their high accuracy, and confirm the theoretical analysis well.
