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A large number of modular multilevel converters (MMC) are connected to HVDC transmission systems nowadays. This paper aims at the short-circuit fault in the DC line of the HVDC transmission system and the problem of capacitor voltage imbalance in MMC, proposing a new type of MMC sub-module, which has both the DC fault self-clearing ability and the capacitor voltage self-balancing ability. This sub-module combines the topology of half bridge and full bridge. It uses the reverse capacitor voltage to forcibly turn off the conducting diode to block the fault current loop. At the same time, the two capacitances charge and discharge states are consistent by utilizing the operating mode of the sub-module. It is possible to directly achieve a self-balancing capacitor voltage without complex balancing voltage control. The MATLAB/Simulink simulation verifies the effectiveness of the DC fault blocking capability and capacitor voltage balance capability of the proposed sub-module.

The Wii balance board (WBB) is a simplified force plate system used to evaluate the balancing ability of the elderly via a sensory interaction task to confirm a significant standing balance index. The accuracy of this system has been verified in previous studies. In this study, an instrumented and modified clinical test of sensory interaction on balance (i-mCTSIB) was performed on 84 elderly subjects, and the variables for center of pressure (CoP) were calculated using WBB for each task condition. The results indicate that the visual condition has a significant effect on the sway proprioceptive sensory variables with a foam condition as their complexity increases. In addition, the correlation between the variable and Berg Balance Scale was not confirmed since CTSIB is a sensory interaction on balance ability. Therefore, WBB can be used to evaluate balancing ability based on sensory interactions consisting of the surface condition.

The aim of the study was the examination of the relationships among gymnasts’ training age, body mass index (BMI), balance control during the execution of handstand, standing scale forward, and stork standing in relevé position, and their performance in competition settings. Forty young competitive gymnasts (20 males; age: 12.20 ± 1.98 years, and 20 females; age: 12.33 ± 2.07 years, mean ± SD) participated in this study. A portable digital platform for posturography was used to measure maximal pressure, center of pressure (CoP) sway area, CoP linear distance displacement and CoP velocity. The resulting data were analyzed using an integrated software module (Foot Checker, version 4.0). The results confirm the reliability of the measurements. Strong positive correlations were found between gymnasts' performance in the gymnastics competition, and their training age and BMI, with relationships also identified between performance and variables related to balance control. Regression analysis revealed that gymnasts' training age, BMI, and balance control in performing the assessed gymnastics skills had predictive significance in determining their performance in the competition, taking into account differences between age groups. Despite the limitations of the study, the results represent a valuable contribution to the literature by expanding knowledge about predicting gymnastics performance in competition. Furthermore, the results provide evidence for the identification of talent in gymnasts, offer coaches insights to improve training efficiency, and provide recommendations for future research in this area. Namen raziskave je bil preučiti povezave med leti vadbe telovadcev, indeksom telesne mase (ITM), nadzorom ravnotežja med izvajanjem stoje na rokah, razovke stojno zanožno in stoji na eni nogi v vzponu ter njihovo uspešnost v tekmovalnih okoljih. V tej raziskavi je sodelovalo 40 mladih  telovadcev in telovadk (20 moških; starost: 12,20 ± 1,98 let in 20 žensk; starost: 12,33 ± 2,07 let, povprečje ± SD). Prenosna pritiskovna plošča je bila uporabljena za merjenje najvišjega tlaka, območja nihanja središča tlaka (CoP), premika premočrtne razdalje CoP in hitrosti CoP. Dobljene podatke smo razčlenili z vgrajenim programom (Foot Checker, različica 4.0). Rezultati potrjujejo zanesljivost meritev. Ugotovljene so bile močne pozitivne povezave med uspešnostjo telovadcev na tekmovanju ter njihovimi leti vadbe in ITM, pri čemer so bila ugotovljena tudi razmerja med uspešnostjo in spremenljivkami, povezanimi z nadzorom ravnotežja. Regresijska metoda je pokazala, da imajo leta vadbe, ITM in nadzor ravnotežja pri izvajanju telovadnih prvin napovedni pomen pri določanju njihove uspešnosti na tekmovanju, ob upoštevanju razlik med starostnimi skupinami. Kljub omejitvam raziskave rezultati predstavljajo dragocen prispevek k literaturi z razširitvijo znanja o napovedovanju telovadne uspešnosti na tekmovanju. Poleg tega rezultati zagotavljajo dokaze za prepoznavanje nadarjenosti pri telovadcih, vaditeljem ponujajo vpogled v izboljšanje učinkovitosti vadbe in dajejo priporočila za prihodnje raziskave na tem področju.

PurposeTo systematically evaluate the effect of Baduanjin on the balancing ability of older adults.MethodsThe systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Six electronic databases were searched for eligible studies. Data synthesis and statistical analysis using a random effects model were performed with Review Manager 5.4. Random-effects weights were used to pool the effect sizes. Publication bias was assessed by funnel plot.ResultsA total of 17 RCTs involving 1,267 patients were identified. The meta-analysis showed that the Baduanjin group was significantly superior to the control group in balancing performance measured by Berg balance scale [mean difference (MD) 4.82; 95% confidence interval (CI) 3.40 to 6.24, P < 0.00001], Timed Up and Go (MD −2.21, 95% CI −2.69 to −1.74, P < 0.00001) and Eye Closed One Leg Standing Balance (MD 2.01, 95% CI 0.79 to 3.23, P < 0.00001) tests.ConclusionBaduanjin can effectively affect the balancing ability of older adults. More high-quality evidence-based studies are required to confirm these findings.Systematic review registration[https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=293183], identifier [CRD42021293183].

Purpose In the case of Hungarian folk dancers, it is crucial to maintain correct posture and promptly respond to imbalances. However, traditional dances often lack specific training to develop these skills. Methods In this present study, twelve dancers (8 male, 4 female, age: 21.7 ± 3.6 years) and ten non-dancers subjects forming a control group (6 male, 4 female, age: 21.6 ± 2.87 years) participated. During the measurements a 60-second long bipedal balancing test on the balance board was completed two times, and a spinning intervention was inserted in between the two sessions. The balance capabilities of the two groups were assessed through the characterization of motion on an unstable board, and the analysis of subject’s center of mass and head movements. Results Dancers applied a more sophisticated and resource-intensive strategy to address the balancing task, yielding a better balancing performance in terms of balance board parameters. By preferring a solid stability in the medio-lateral direction, a greater fluctuation in the anterior-posterior direction can be observed (e.g., significantly lower SampEn values). The overall more successful performance is further evidenced by within-subject comparison since significant differences were observed mostly within the control group. Based on the results, the advanced balancing ability of the folk dancer group is more likely to be acquired through years of experience. Conclusion The results indicate that additional specialized training could further enhance this ability, encouraging the reliance on poorly memorized corrective movements and reducing the risk of injury.

Neurological patients using a powered lower-body exoskeleton for rehabilitation of standing and walking skills in an upright body pose face the safety challenge of postural instability and fall. Current research, therefore, develops exoskeletons with self-balancing functions. This study suggests basing the exoskeleton’s stabilization of standing posture on a human-derived postural control mechanism. A corresponding control system has previously been successfully tested with specific balancing tasks in humanoid robots. Here, we provide a short introduction into the control method and, using a lightweight robot, present as a test of the balancing an experimental shift in the body weight distribution (as if, e.g., a human exoskeleton user was raising an arm or leaning the upper body or lifting an external weight). An overview of other specific balancing tests previously already investigated in humans and humanoids is also briefly mentioned. Overall, the tests will allow the quantification of the capabilities of self-balancing exoskeletons developed for patients with partial paralysis of lower body sensorimotor functions.

The space vector modulation strategy for the three-phase/wire/level VIENNA rectifier is analysed in this study. Furthermore, the voltage balancing ability of DC-link neutral point is demonstrated as well. The maximum unbalanced rate between the loads for dual-output under different modulation indices m is theoretically calculated when the converter works in unity power factor. A robust controller to balance the output voltage under the unbalanced load for different modulation indices is proposed. An experimental prototype was built to verify the theoretical analysis. The voltages for dual-output are balanced when the converter works as a power factor corrector, and therefore the theoretical analysis is verified. Finally, the series of tested maximum unbalanced rate between the loads for dual-output under different modulation indices m was given, which verifies the theoretical analysis.

The purpose of this study was to evaluate the influence of fear of falling on balancing ability during abrupt deceleration in aged women. The subjects were 20 women aged between 67 and 75 years. They were classified into two groups, one having a fear of falling (group FF, n = 10) and another without this fear (group NFF, n = 10). The two groups had similar daily physical activities. Changes in the centre of foot pressure (CFP) were measured during postural sway following horizontal deceleration of the force platform on which they were standing, and the response time and CFP displacement were evaluated. In addition, the electromyogram (EMG) onset in the tibialis anterior muscle and medial gastrocnemius muscle during abrupt deceleration, and its difference between the two muscles were measured. and the relative level of co-contraction of antagonistic muscles (the co-contraction index, CCI) in the lower extremity muscle group was calculated. The response time and CFP displacement immediately after abrupt deceleration were significantly higher in group FF than in NFF (P < 0.05). The EMG onset in the two muscles did not significantly differ between the two groups. The difference in EMG onset between the two muscles was significantly lower in group FF than in NFF (P < 0.05). The CCI was significantly higher in group FF than in NFF (P < 0.05). These results suggest that there were negative effects of a fear of falling on the balancing ability immediately after abrupt deceleration. This may be because a fear of falling increases the co-contraction of antagonist muscles in the lower extremity muscle group.

Age-related differences in postural control in response to a relatively large deceleration resulting from postural disturbance were investigated in eight normal elderly men (age range 67-72 years) and eight young men as controls (age range 19-22 years) using a moving platform. Data were obtained for the hip, knee and ankle angles, position of the centre of foot pressure (CFP), head acceleration, and muscle activity of the leg muscles. The elderly subjects had slower and larger ankle and hip joint movements, and CFP displacement in response to the disturbance compared to the young controls. The elderly subjects also had a delayed occurrence, and greater magnitude of peak acceleration of head rotation than did the young subjects. For the elderly subjects, the CFP was closely related to angular changes in the hip joint movement, but not to those of the ankle and knee joint movements. For the young subjects, on the other hand, the CFP was significantly correlated with angular change in the ankle joint. Cocontraction of the tibialis anterior and gastrocnemius muscles was observed in the elderly subjects. The results indicated that a movement pattern for postural correction in the elderly adults was different from that of the young adults. The elderly relied more on hip movements while the young controls relied on ankle movements to control postural stability.

Unimensional accounts of revisionism – those that align states along a single continuum from supporting the status quo to seeking a complete overhaul of the international system – miss important variation between a desire to alter the balance of military power and a desire to alter other elements of international order. We propose a two-dimensional property space that generates four ideal types: status-quo actors, who are satisfied with both order and the distribution of power; reformist actors, who are fine with the current distribution of power but seek to change elements of order; positionalist actors, who see no reason to alter the international order but do aim to shift the distribution of power; and revolutionary actors, who want to overturn both international order and the distribution of capabilities. This framework helps make sense of a number of important debates about hegemony and international order, such as the possibility of revisionist hegemonic powers, controversies over the concept of ‘soft balancing’, and broader dynamics of international goods substitution during power transitions.