PurposeAn enhanced recovery after surgery (ERAS) protocol incorporates up-to-date perioperative care principles; the primary aim in using an ERAS protocol is to reduce issues that delay the recovery and cause the complications. The aim of this study was to compare outcomes associated with head and neck cancer surgery with free-flap reconstruction before and after implementation of an ERAS protocol.MethodsOutcomes were analyzed by dividing patients into 2 groups: 29 patients in the non-ERAS group and 60 patients in the ERAS group. The ERAS group performed a prospective observational cohort study of patients who underwent a head and neck cancer surgery with free-flap reconstruction in Ajou University Hospital from August 2015 to December 2017. The non-ERAS group retrospectively reviewed the medical records of patients who had undergone the same surgery from August 2012 to July 2015.ResultsDemographics, comorbidities, hospital length of stay (LOS), postoperative complications, starting time of rehabilitation, and postoperative periods before radiotherapy for the non-ERAS and ERAS groups were compared. Hospital LOS was significantly lower for patients whose care followed the ERAS protocol than for patients in the non-ERAS group (30.87 ± 20.72 days vs. 59.66 ± 40.43 days, P < 0.0001).ConclusionIn this study, hospital LOS was reduced through fast recovery after the implementation of the ERAS protocol. Therefore, the ERAS protocol appeared feasible and safe in head and neck cancer surgery with free-flap reconstruction.

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This paper investigates the adaptive incremental backstepping sliding mode control for the rotorcraft trajectory-tracking control problem to enhance the robustness to the matched uncertainty in the model. First, the incremental dynamics is used for the control design to exclude the adverse effect of the mismatched model uncertainties on the trajectory-tracking performance. Secondly, the sliding-mode control strategy is adopted in the second design stage of the backstepping controller, and the effect of switching gains on the controller robustness is thoroughly studied using the rotorcraft model with different levels of the matched uncertainties. To clarify the robustness enhancement using the adaptive selection of switching gains, this paper chooses three different control structures consisting of the traditional backstepping control and two backstepping sliding mode controls with the fixed or adaptively adjusted switching gains. These control designs are applied to the trajectory-tracking control for the helical-turn maneuver of the Bo-105 helicopter to compare their relative robustness to the matched uncertainties. The results prove that adaptive incremental backstepping sliding mode control shows much higher robustness than other two designs, and the controller even with the fixed switching gains can be used to improve the robustness of the pure backstepping control design. Therefore, the present adaptive incremental backstepping sliding mode control is effectively applicable with the rotorcraft model which typically contains many different sources of both matched and mismatched uncertainties.

Recently, interest in mission autonomy related to Unmanned Combat Aerial Vehicles(UCAVs) for performing highly dangerous Air-to-Surface Missions(ASMs) has been increasing. Regarding autonomous mission planners, studies currently being conducted in this field have been mainly focused on creating a path from a macroscopic 2D environment to a dense target area or proposing a route for intercepting a target. For further improvement, this paper treats a mission planning algorithm on an ASM which can plan the path to the target dense area in consideration of threats spread in a 3D terrain environment while planning the shortest path to intercept multiple targets. To do so, ASMs are considered three sequential mission elements: ingress, intercept, and egress. The ingress and egress elements require a terrain flight path to penetrate deep into the enemy territory. Thus, the proposed terrain flight path planner generates a nap-of-the-earth path to avoid detection by enemy radar while avoiding enemy air defense threats. In the intercept element, the shortest intercept path planner based on the Dubins path concept combined with nonlinear programming is developed to minimize exposure time for survivability. Finally, the integrated ASM planner is applied to several mission scenarios and validated by simulations using a rotorcraft model.

This paper investigates an adaptive backstepping control based on the immersion-and-invariance (I&I) method for a rotorcraft’s trajectory-tracking control problem. To effectively cope with both parametric uncertainties and external disturbances affecting all forces and moments of a rotorcraft, the I&I-based disturbance observer is designed and combined with an adaptive backstepping controller. During the design process, a simple form of the observer structure is suggested, and the performance of the observer is analyzed using a candidate Lyapunov function. Then, the closed-loop stability of the adaptive controller is analyzed for both time-invariant and time-varying disturbances. Additionally, the tuning function-based adaptive backstepping controller is designed and used to investigate the outperformance achievable with the proposed method. Finally, comparative simulation results using a high-fidelity rotorcraft math model is provided to show the effectiveness of the proposed strategy.