The authors consider a robust optimal reinsurance and investment problem in a risk model with two dependent classes of insurance business for an Ambiguity-Averse insurer(AAI).The insurer aims to minimize the goal-reac...The authors consider a robust optimal reinsurance and investment problem in a risk model with two dependent classes of insurance business for an Ambiguity-Averse insurer(AAI).The insurer aims to minimize the goal-reaching probability that the value of the wealth process reaches a low barrier before a high goal.Using the stochastic control approach based on the Hamilton-JacobiBellman(HJB)equation,the authors derive the robust optimal reinsurance and investment strategies,as well as the corresponding value function.The authors conclude that the robust optimal investmentreinsurance strategy coincides with the one without model ambiguity,but the value function differs.As a consequence,ignoring model uncertainty leads to significant value function loss for the AAI.Besides,it is worth noting that if the insurer has only one business,the sum of the degenerated value function and the one of(Luo,et al.,2019)is equal to 1 both for ambiguity and ambiguity-neutral.Finally,numerical examples are given to illustrate our results.展开更多
AIM To compare the efficacy of a session of extracorporeal shock wave lithotripsy(ESWL) before endoscopic retrograde cholangiopancreatography(ERCP) vs ERCP only for problematic and large common bile duct(CBD) stones.M...AIM To compare the efficacy of a session of extracorporeal shock wave lithotripsy(ESWL) before endoscopic retrograde cholangiopancreatography(ERCP) vs ERCP only for problematic and large common bile duct(CBD) stones.METHODS Adult patients with CBD stones for whom initial ERCP was unsuccessful because of the large size of CBD stones were identified. The patients were randomized into two groups,an "ESWL + ERCP group" and an "ERCP-only" group. For ESWL + ERCP cases,ESWL was performed prior to ERCP. Clearance of the CBD,complications related to the ESWL/ERCP procedure,frequency of mechanical lithotripsy use and duration of the ERCP procedure were evaluated in both groups.RESULTS There was no significant difference in baseline characteristics between the two groups. A session of ESWL before ERCP compared with ERCP only resulted in similar outcomes in terms of successful stone removal within the first treatment session(74.2% vs 71.0%,P = 0.135),but a higher clearance rate within the second treatment session(84.4% vs 51.6%,P = 0.018) and total stone clearance(96.0% vs 86.0%,P = 0.029). Moreover,ESWL prior to ERCP not only reduced ERCP procedure time(43 ± 21 min vs 59 ± 28 min,P = 0.034) and the rate of mechanical lithotripsy use(20% vs 30%,P = 0.025),but also raised the clearance rate of extremely large stones(80.0% vs 40.0%,P = 0.016). Post-ERCP complications were similar for the two groups.CONCLUSION Based on the higher rate of successful stone removal and minimal complications,ESWL prior to ERCP appears to be a safe and effective treatment for the endoscopic removal of problematic and large CBD stones.展开更多
阐述IEC 60364-4-41:2005《Lowvoltage electrical installations—Part 4-41:Protection for safety—Protection against electric shock》标准规定TT系统内由同一保护电器所保护的所有电气设备必须采用共用接地防电击的原由,举例说...阐述IEC 60364-4-41:2005《Lowvoltage electrical installations—Part 4-41:Protection for safety—Protection against electric shock》标准规定TT系统内由同一保护电器所保护的所有电气设备必须采用共用接地防电击的原由,举例说明户外农电装置、施工场地、路灯等TT系统应用中的接地和防电击实施方案。着重叙述路灯TT系统共用接地并采用过电流防护电器兼防电击在我国的特殊现实意义。展开更多
基金supported by the Natural Science Foundation of Hunan Province under Grant No.2023JJ30381the Changsha Municipal Natural Science Foundation under Grant No.kq2208159+2 种基金the Humanities and Social Science Fund of Ministry of Education of China under Grant No.23YJC910008the Graduate Research and Innovation Project of Hunan Province under Grant No.CX20230241the Graduate Research and Innovation Project of Central South University under Grant No.1053320222639。
文摘The authors consider a robust optimal reinsurance and investment problem in a risk model with two dependent classes of insurance business for an Ambiguity-Averse insurer(AAI).The insurer aims to minimize the goal-reaching probability that the value of the wealth process reaches a low barrier before a high goal.Using the stochastic control approach based on the Hamilton-JacobiBellman(HJB)equation,the authors derive the robust optimal reinsurance and investment strategies,as well as the corresponding value function.The authors conclude that the robust optimal investmentreinsurance strategy coincides with the one without model ambiguity,but the value function differs.As a consequence,ignoring model uncertainty leads to significant value function loss for the AAI.Besides,it is worth noting that if the insurer has only one business,the sum of the degenerated value function and the one of(Luo,et al.,2019)is equal to 1 both for ambiguity and ambiguity-neutral.Finally,numerical examples are given to illustrate our results.
文摘AIM To compare the efficacy of a session of extracorporeal shock wave lithotripsy(ESWL) before endoscopic retrograde cholangiopancreatography(ERCP) vs ERCP only for problematic and large common bile duct(CBD) stones.METHODS Adult patients with CBD stones for whom initial ERCP was unsuccessful because of the large size of CBD stones were identified. The patients were randomized into two groups,an "ESWL + ERCP group" and an "ERCP-only" group. For ESWL + ERCP cases,ESWL was performed prior to ERCP. Clearance of the CBD,complications related to the ESWL/ERCP procedure,frequency of mechanical lithotripsy use and duration of the ERCP procedure were evaluated in both groups.RESULTS There was no significant difference in baseline characteristics between the two groups. A session of ESWL before ERCP compared with ERCP only resulted in similar outcomes in terms of successful stone removal within the first treatment session(74.2% vs 71.0%,P = 0.135),but a higher clearance rate within the second treatment session(84.4% vs 51.6%,P = 0.018) and total stone clearance(96.0% vs 86.0%,P = 0.029). Moreover,ESWL prior to ERCP not only reduced ERCP procedure time(43 ± 21 min vs 59 ± 28 min,P = 0.034) and the rate of mechanical lithotripsy use(20% vs 30%,P = 0.025),but also raised the clearance rate of extremely large stones(80.0% vs 40.0%,P = 0.016). Post-ERCP complications were similar for the two groups.CONCLUSION Based on the higher rate of successful stone removal and minimal complications,ESWL prior to ERCP appears to be a safe and effective treatment for the endoscopic removal of problematic and large CBD stones.
文摘阐述IEC 60364-4-41:2005《Lowvoltage electrical installations—Part 4-41:Protection for safety—Protection against electric shock》标准规定TT系统内由同一保护电器所保护的所有电气设备必须采用共用接地防电击的原由,举例说明户外农电装置、施工场地、路灯等TT系统应用中的接地和防电击实施方案。着重叙述路灯TT系统共用接地并采用过电流防护电器兼防电击在我国的特殊现实意义。
