Variable stiffness actuator is a new actuation of robot which is inspired by motor control of human arm. And it is promising way to exploit the human-like performance and human-like motion. However, due to the mechanical complexity and redundancy of the actuators, it is not trivial to control the variable stiffness actuated robot to perform a human-like motion. In this paper, the weight lifting problem with variable stiffness actuated robot is studied. Then, the original problem is formulated as a constrained optimal control problem and transformed as a general nonlinear programming problem with Gauss pseudospectral method. Simulation studies demonstrate the effectiveness of the proposed method compared with the iLQR approach. Furthermore, the simulations results are presented to show the influence of stiffness variation of variable stiffness actuators on the weight lifting problem.
Offshore wind energy has become the fastest growing form of renewable energy for the last few years. And the development of offshore wind farms (OWFs) is now characterized by a boom. OWF siting is crucial in the success of wind energy projects. Therefore, this paper aims to introduce intelligent algorithms to improve the siting assessment under conditions of multisource and uncertain information. An optimization macrositing model based on Cloud-Bayesian Network (Cloud-BN) is put forward. We introduce the cloud model and adaptive Gaussian cloud transformation (A-GCT) algorithm to grade indicators and apply BN to achieve nonlinear integration and inference of multi-indicators. Combined with the fuzzy representation of the cloud model and probabilistic reasoning of BN, the proposed model can investigate the most efficient siting areas of OWFs in the North Sea of Europe. The experimental results indicate that the siting accuracy is up to % with reference to the actual OWF location.
The widespread application of wireless mobile services and requirements of ubiquitous access have resulted in drastic growth of the mobile traffic and huge energy consumption in ultradense networks (UDNs). Therefore, energy-efficient design is very important and is becoming an inevitable trend. To improve the energy efficiency (EE) of UDNs, we present a joint optimization method considering user association and small-cell base station (SBS) on/off strategies in UDNs. The problem is formulated as a nonconvex nonlinear programming problem and is then decomposed into two subproblems: user association and SBS on/off strategies. In the user association strategy, users associate with base stations (BSs) according to their movement speeds and utility function values, under the constraints of the signal-to-interference ratio (SINR) and load balancing. In particular, taking care of user mobility, users are associated if their speed exceeds a certain threshold. The macrocell base station (MBS) considers user mobility, which prevents frequent switching between users and SBSs. In the SBS on/off strategy, SBSs are turned off according to their loads and the amount of time required for mobile users to arrive at a given SBS to further improve network energy efficiency. By turning off SBSs, negative impacts on user associations can be reduced. The simulation results show that relative to conventional algorithms, the proposed scheme achieves energy efficiency performance enhancements.
This paper establishes the equivalent relationships between the half-sinusoidal load, triangular load, vertical stepwise load, and moving traffic load. The governing equation was established for analyzing the dynamic responses of pavement, and half-sinusoidal load, triangular load, and vertical stepwise load functions were transformed into Fourier series expressions. The partial differential governing equations were simplified as ordinary differential equations and the analytical solutions were obtained. Further, the solutions were validated through comparing the theoretical results with numerical simulated results. Calculation results revealed that, for unchanged load periods, increasing the amplitudes of the three loads by 1.06, 1.31, and 1.35 times can better simulate the moving traffic loads. For unchanged load function amplitudes, increasing the function periods by 1.07, 2.23, and 2.1 times (for half-sinusoidal, triangular, and vertical stepwise loads, resp.) can improve the simulation performance. The fatigue life of asphalt pavements under the moving traffic load agrees with that of the three load simulations, indicating that the fatigue life of asphalt pavements is only associated with the load amplitude but not the load patterns.
Dichloromethane:methanol (1:1, v/v) extracts of different maturity stages (immature, partly mature, and mature) of authenticated leaves of Ceylon cinnamon (CC) were used in this study. Antioxidant properties [total polyphenolic content (TPC) and total flavonoid content (TFC), 1, 1-diphenyl-2-picryl-hydrazyl (DPPH), 2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS)), oxygen radical absorbance capacity (ORAC), and ferric reducing antioxidant power (FRAP)] and glycemic regulatory properties [antiamylase (AA); antiglucosidase (AG)] were evaluated using 96-well microplate based bio assays in vitro (TPC, TFC, DPPH, ABTS, ORAC n=4 each; FRAP, AA, AG n=3 each). Results clearly revealed significant differences (p partly mature leaf > immature leaf. This is the first study to report on antioxidant and glycemic regulatory properties of different maturity stages of leaf of Ceylon cinnamon and highlights its potential use in management of oxidative stress-associated chronic diseases including diabetes mellitus.
Objective. The aim of the study was to establish, by means of linear regressions analysis, whether RANTES and CCL2 have a relationship with age, sex, heart rate, ejection fraction, white blood cells count, monocyte count, platelet count, mean platelet volume, hsCRP concentration, creatinine and eGFR value, applied treatments, and coronary risk factors in polish cardiovascular disease patients. Methods. Plasma chemokines concentrations were measured by ELISA method (R&D Systems Europe Ltd., Abingdon, England) in 115 cardiovascular disease patients (83 myocardial infarction/AMI and 32 stable angina/SA) and in the control group (N=25). Results. Univariate linear regression analysis found that (1) for men mean RANTES plasma level is 1.56 times higher as compared to women; (2) if patient’s age increases by 1 year, the mean RANTES concentration value increases by 1.4%; (3) if CCL2 concentration increases by 10 pg/mL, the mean RANTES concentration value increases by 3.3%; (4) if hsCRP concentration increases by 1 mg/L, the mean RANTES concentration value increases by 1.0%. By means of multiple linear regression analysis we found that (1) for men the mean plasma RANTES concentration value increases 1.89 times as compared to women; (2) if CCL2 concentration increases by 10 pg/mL, the mean RANTES concentration value increases by 3.4%; (3) if MPV increases by 1 fL, the mean RANTES concentration value increases by 12%, if other model parameters are fixed. For CCL2 we did not obtain statistically significant linear regression models. Conclusion. Due to high variability of obtained CCL2 concentrations, it seems that RANTES better reflects the presence of the atherosclerotic lesion than CCL2. RANTES as a marker of atherosclerotic process may be an important therapeutic target, and the assessment of RANTES concentration should be interpreted depending on patient’s sex, age, platelet hyperactivity state, hsCRP, and CCL2 concentration.
Introduction. Delirium during ICU stay is a widespread problem with complex aetiology. A premorbid psychiatric disorder has been associated with an increased incidence of delirium in the general hospital population, but data on the impact of ICU delirium and consequences for morbidity and long-term mortality remain scarce. Methods. In this single-centre retrospective analysis, 472 patients with an ICU stay >48 hours were included during a 2-year period. Postresuscitation and neurosurgical patients were not included. The primary aim of the study was to establish the incidence and duration of delirium during ICU stay in patients with (PS group) and without (NPS group) a premorbid psychiatric disorder. Data were analysed with applicable nonparametric tests. In a secondary analysis, patients were compared according to the presence or absence of delirium. Finally, a binary logistic regression model was constructed to correct for potential confounders. Results. Of all patients, 19.7% were included in the PS group. Baseline characteristics with respect to severity of illness and type of admission did not differ between groups, but PS patients were significantly younger and more often female in comparison with NPS patients. The overall incidence of delirium during ICU was 57% and did not significantly differ between groups (65% in PS group vs. 56% in the NPS group, ). In a univariate analysis, the presence of a psychiatric history was also associated with prolonged mechanical ventilation, length of stay ICU, and hospital stay, but not with long-term all-cause mortality. The presence of delirium at any time during ICU admission was significantly associated with prolonged mechanical ventilation and prolonged ICU and hospital stay, but not with mortality. In a Kaplan–Meier analysis, 5-year all-cause mortality was clearly separated between groups, but the difference remained statistically insignificant (,). In a binary logistic regression model, age, male sex, APACHE III score, and premorbid psychiatric disorder (OR 1.8, CI 1.1–3.0; ) were all independently associated with the presence of delirium. Conclusions. In ICU patients with a length of stay >48 hours and a premorbid psychiatric disorder, the incidence of delirium was not significantly higher in comparison with patients without a premorbid psychiatric disorder.
Coagulation factor XIII (FXIII) is the final enzyme in the coagulation cascade and plays an important role in catalyzing the intermolecular cross-linking of fibrin polymers. FXIII deficiency is a rare disorder that presents with recurrent soft tissue bleeding. In this case report, we describe a patient with recurrent hematomas, following a revision total hip arthroplasty (THA). A 50-year-old female patient with no past history of bleeding and with a normal perioperative coagulation profile presented with recurrent hip joint hematomas. Her plasma FXIII activity showed a slight decrease (69%). Therefore, the patient was diagnosed with an acquired deficiency and was administered FXIII to correct it. The bleeding did not recur once the FXIII activity had returned to a normal level (76%). At 2 months after the second evacuation procedure, the patient was discharged from the hospital in an ambulatory state. There has been no recurrence of a hematoma since. We managed a rare case of acquired FXIII deficiency, which highlighted that a patient can present with an acquired bleeding disorder despite having a normal coagulation profile. An acquired FXIII deficiency should be suspected in patients with inexplicable, sudden-onset bleeding, as early diagnosis and treatment are important to prevent life-threatening complications.
The main purpose of this paper is to investigate the mechanism of sliding phenomenon in Filippov (nonsmooth) dynamical systems by attractor analysis and vector analysis. A corresponding simple model based on Chua’s circuit with periodic excitation was introduced as an example. The attractor analysis proposed in our previous work is used to discuss the complicated oscillations of the Filippov system. However, it failed to perfectly explain the sliding phenomena and establish an analytical method of constant voltage control. Therefore, the geometric structure and analytic conditions of sliding bifurcations in the general n-dimensional piecewise smooth system are discussed in detail by vector structure analysis. The prospects of practical application of this method are also discussed in the end.