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In most situations, the high performance of permanent magnet synchronous motors (PMSMs) depends on an absence of chaos; consequently, suppressing chaos becomes quite important. Therefore, this study confirms the chaotic motion and then applies synchronization to a chaotic PMSM system to control chaos. Rich dynamics of the PMSM system are studied using a bifurcation diagram, phase portraits, a Poincaré map, frequency spectra and Lyapunov exponents. First, the largest Lyapunov exponent is estimated using synchronization to identify periodic and chaotic motions. Next, complex nonlinear behaviors are thoroughly observed throughout a range of parameter values in the bifurcation diagram. Finally, a proposed continuous feedback control method based on synchronization characteristics eliminated chaotic oscillations. Numerical simulations are utilized to verify the feasibility and efficiency of the proposed control technique.

Introduction. Low back pain (LBP) is one of the most common complaints in the emergency department (ED). There are several research articles providing evidence for acupuncture for treating chronic LBP but few about treating acute LBP. This study assessed the efficacy and safety of acupuncture for the treatment of acute LBP in the ED. Materials and methods. A clinical pilot cohort study was conducted. 60 participants, recruited in the ED, were divided into experimental and control groups with 1 dropout during the study. Life-threatening conditions or severe neurological defects were excluded. The experimental group (n = 45) received a series of fixed points of acupuncture. The control group (n = 14) received sham acupuncture by pasting seed-patches near acupoints. Back pain was measured using the visual analog scale (VAS) at three time points: baseline and immediately after and 3 days after intervention as the primary outcome. The secondary outcomes were heart rate variability (HRV) and adverse events. Results. The VAS demonstrated a significant decrease (P value <0.001) for the experimental group after 15 minutes of acupuncture. The variation in HRV showed no significant difference in either group. No adverse event was reported. Conclusion. Acupuncture might provide immediate effect in reducing the pain of acute LBP safely.

BackgroundDizziness and vertigo account for roughly 4% of chief symptoms in the emergency department (ED). Pharmacological therapy is often applied for these symptoms, such as vestibular suppressants, anti-emetics and benzodiazepines. However, every medication is accompanied with unavoidable side-effects. There are several research articles providing evidence of acupuncture treating dizziness and vertigo but few studies of acupuncture as an emergent intervention in ED. We performed a pilot cohort study to evaluate the efficacy and safety of acupuncture in treating patients with dizziness and vertigo in ED.MethodsA total of 60 participants, recruited in ED, were divided into acupuncture and control group. Life-threatening conditions or central nervous system disorders were excluded to ensure participants’ safety. The clinical effect of treating dizziness and vertigo was evaluated by performing statistical analyses on data collected from questionnaires of Dizziness Handicap Inventory (DHI), Visual Analog Scale (VAS) of dizziness and vertigo, and heart rate variability (HRV).ResultsThe variation of VAS demonstrated a significant decrease (p-value: 0.001 and p-value: 0.037) between two groups after two different durations: 30 mins and 7 days. The variation of DHI showed no significant difference after 7 days. HRV revealed a significant increase in high frequency (HF) in the acupuncture group. No adverse event was reported in this study.ConclusionAcupuncture demonstrates a significant immediate effect in reducing discomforts and VAS of both dizziness and vertigo. This study provides clinical evidence on the efficacy and safety of acupuncture to treat dizziness and vertigo in the emergency department.Trial registrationClinicalTrials.gov ID: NCT02358239. Registered 5 February 2015

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