A voltage-sensorless control method to balance the input currents of a three-wire boost rectifier under unbalanced input voltages condition

This paper proposes a control method that can balance the input currents of the three-phase three-wire boost rectifier under unbalanced input voltage condition. The control objective is to operate the rectifier in the high-power-factor mode under balanced input voltage condition but to give overriding priority to the current balance function in case of unbalance in the input voltage. The control structure has been divided into two major functional blocks. The inner loop current-mode controller implements resistor emulation to achieve high-power-factor operation on each of the two orthogonal axes of the stationary reference frame. The outer control loop performs magnitude scaling and phase-shifting operations on current of one of the axes to make it balanced with the current on the other axis. The coefficients of scaling and shifting functions are determined by two closed-loop prportional-integral (PI) controllers that impose the conditions of input current balance as PI references. The control algorithm is simple and high performing. It does not require input voltage sensing and transformation of the control variables into a rotating reference frame. The simulation results on a MATLAB-SIMULINK platform validate the proposed control strategy. In implementation Texas Instrument's digital signal processor TMS320F24OF is used as the digital controller. The control algorithm for high-power-factor operation is tested on a prototype boost rectifier under nominal and unbalanced input voltage conditions.

Leisure sports and postural control:Can a black belt protect your balance from aging?

To determine potential benefits of intensive leisure sports for age-related changes in postural control, we tested 3 activity groups comprising 70 young (M = 21.67 years, SD = 2.80) and 73 older (M = 62.60 years, SD = 5.19) men. Activity groups were martial artists, who held at least 1st Dan (black belt), sportive individuals exercising sports without explicit balance components, and nonsportive controls. Martial artists had an advantage over sportive individuals in dynamic posture tasks (upright stance on a sway-referenced platform), and these 2 active groups showed better postural control than nonsportive participants. Age-related differences in postural control were larger in nonsportive men compared with the 2 active groups, who were similar in this respect. In contrast, negative age differences in other sensorimotor and cognitive functions did not differ between activity groups. We concluded that individuals engaging in intensive recreational sports have long-term advantages in postural control. However, even in older martial artists with years of practice in their sports, we observed considerable differences favoring the young. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

A Smart Grid Information System for Demand Side Participation: Remote Control of Domestic Appliances to Balance Demand

Due to the intermittent nature of renewable generation it is desirable to consider the potential of controlling the demand-side load to smooth overall system demand. The architecture and control methodologies of such a system on a large scale would require careful consideration. Some of these considerations are discussed in this paper; such as communications infrastructure, systems architecture, control methodologies and security. A domestic fridge is used in this paper as an example of a controllable appliance. A layered approach to smart-grid is introduced and it can be observed how each smart-grid component from physical cables, to the end-devices (or smart-applications) can be mapped to these set layers. It is clear how security plays an integral part in each component of the smart-grid so this is also an integral part of each layer. The controllable fridge is described in detail and as one potential smart-grid application which maps to the layered approach. A demonstration system is presented which involves a Raspberry Pi (a low-power, low-cost device representing the appliance controller).

Postural control and functional balance in individuals with diabetic peripheral neuropathy

A Neuropatia diabética periférica (NDP) cursa com redução somatossensitiva que pode levar a alterações no controle postural. O objetivo do estudo foi avaliar o controle postural na postura ereta, em diferentes condições, e o equilíbrio funcional em indivíduos com NDP, correlacionar os resultados obtidos na avaliação do controle postural com os valores do teste do equilíbrio funcional e comparar os resultados obtidos no grupo neuropata com o grupo controle, verificando as possíveis diferenças entre as condições de avaliação em ambos os grupos. Participaram do estudo 13 mulheres com NDP (GN) e 17 mulheres não diabéticas (GC). A avaliação do controle postural foi realizada por cinemetria nas condições: olhos abertos (OA), olhos fechados (OF) e semi tandem (ST). Após processamento no MATLAB, foram geradas as variáveis: amplitude média de oscilação (AMO) na direção ântero-posterior (AP) e médio-lateral (ML); e velocidade média de oscilação (VMO) na direção AP e ML. O equilíbrio funcional foi avaliado pelo Timed Up and Go Test. Houve diferença significante entre os grupos (p<0,005) na AMO-AP OA e OF, AMO-ML of e ST e VMO-ML ST. Houve diferença entre as condições OA e ST (p<0,005) e of e ST (p<0,005) para as variáveis AMO-ML e VMO-ML, com maior prejuízo para o GN, que também apresentou um menor equilíbrio funcional (p=0,001). A instabilidade ML foi correlacionada positivamente com o desequilíbrio funcional. Os resultados nos mostram uma alteração no sistema de controle postural na NDP, o que pode levar estes indivíduos a um maior risco a quedas e prejuízos funcionais.

Ajuste del balance de pagos, política crediticia y control del endeudamiento externo = Balance-of-payments adjustment, credit policy and control of the external debt

Incluye Bibliografía

Postural control in elderly women with osteoporosis: comparison of balance, strengthening and stretching exercises. A randomized controlled trial

Objective: To compare the efficacy of balance training associated with muscle strengthening or stretching, relative to no intervention, in the postural control of elderly women with osteoporosis. Design: A randomized, controlled trial. Subjects and interventions: Sample consisted of 50 women aged 65 years or older, with osteoporosis, randomized into one of three groups: strengthening group (n = 17) performed balance training with muscle strengthening; stretching group (n = 17) performed balance training with stretching; and control group (n = 16), no activities. Interventions lasted eight weeks, twice a week, 60 minutes a day. Main measures: Postural control was evaluated by the modified Clinical Test of Sensory Interaction for Balance (CTSIBm) and Limits of Stability Test. Strength was assessed by dynamometry and the shortening of the hamstrings by goniometry. Results: Relative to controls, participants in the strengthening group displayed significantly increased dorsiflexion strength and knee flexion strength, as well as centre of pressure velocity, directional control, and oscillation velocity (CTSIBm test). The stretching group had significantly improvements in hamstring length, knee flexion strength, centre of pressure velocity, and amplitude of movements. Relative to the stretching group, the strengthening group yielded better knee extension strength and directional control. Conclusion: The results suggest that both interventions are effective in improving postural control when compared to the control group, and the strengthening group was superior to the stretching group in knee extension strength and in directional control.

Genetic variability and the hypothalamic control of energy balance

Background. Obesity is a major health problem throughout the industrialized world. Despite numerous attempts to curtail the rapid growth of obesity, its incidence continues to rise. Therefore, it is crucial to better understand the etiology of obesity beyond the concept of energy balance.^ Aims. The first aim of this study was to first investigate the relationship between eating behaviors and body size. The second goal was to identify genetic variation associated with eating behaviors. Thirdly, this study aimed to examine the joint relationships between eating behavior, body size and genetic variation.^ Methods. This study utilized baseline data ascertained in young adults from the Training Interventions and Genetics of Exercise (TIGER) Study. Variables assessed included eating behavior (Emotional Eating Scale, Eating Attitudes Test-26, and the Block98 Food Frequency Questionnaire), body size (body mass index, waist and hip circumference, waist/hip ratio, and percent body fat), genetic variation in genes implicated related to the hypothalamic control of energy balance, and appropriate covariates (age, gender, race/ethnicity, smoking status, and physical activity. For the genetic association analyses, genotypes were collapsed by minor allele frequency, and haplotypes were estimated for each gene. Additionally, Bayesian networks were constructed in order to determine the relationships between genetic variation, eating behavior and body size.^ Results. We report that the EAT-26 score, Caloric intake, percent fat, fiber intake, HEAT index, and daily servings of vegetables, meats, grains, and fats were significantly associated with at least one body size measure. Multiple SNPs in 17 genes and haplotypes from 12 genes were tested for their association with body size. Variation within both DRD4 and HTR2A was found to be associated with EAT-26 score. In addition, variation in the ghrelin gene (GHRL) was significantly associated with daily Caloric intake. A significant interaction between daily servings of grains and the HEAT index and variation within the leptin receptor gene (LEPR) was shown to influence body size.^ Conclusion. This study has shown that there is a substantial genetic component to eating behavior and that genetic variation interacts with eating behavior to influence body size.^

Performance of pressure control valves and flow meters precision in operational irrigation-water balance accuracy

In pressure irrigation-water distribution networks, pressure regulating devices for controlling the discharged flow rate by irrigation units are needed due to the variability of flow rate. In addition, applied water volume is used controlled operating the valve during a calculated time interval, and assuming constant flow rate. In general, a pressure regulating valve PRV is the commonly used pressure regulating device in a hydrant, which, also, executes the open and close function. A hydrant feeds several irrigation units, requiring a wide range in flow rate. In addition, some flow meters are also available, one as a component of the hydrant and the rest are placed downstream. Every land owner has one flow meter for each group of field plots downstream the hydrant. Its lecture could be used for refining the water balance but its accuracy must be taken into account. Ideal PRV performance would maintain a constant downstream pressure. However, the true performance depends on both upstream pressure and the discharged flow rate. The objective of this work is to asses the influence of the performance on the applied volume during the whole irrigation events in a year. The results of the study have been obtained introducing the flow rate into a PRV model. Variations on flow rate are simulated by taking into account the consequences of variations on climate conditions and also decisions in irrigation operation, such us duration and frequency application. The model comprises continuity, dynamic and energy equations of the components of the PRV.

A neuroendocrine role for chemerin in hypothalamic remodelling and photoperiodic control of energy balance

We thank Donna Wallace and the animal house staff for their help with the animal studies. We thank Pat Bain for help in preparing the figures. This work was supported by the Biotechnology and Biological Science Research Council (BBSRC) grant number BB/K001043/1 (G.H., A.W.R., P.N.S., P.J.Mc. and P.J.M.) and the Scottish Government (A.W.R., L.M.T., C.D.M. and P.J.M.).