Objective To investigate the co-effect of Demand-control-support （DCS） model and Effort-reward Imbalance （ERI） model on the risk estimation of depression in humans in comparison with the effects when they are used...Objective To investigate the co-effect of Demand-control-support （DCS） model and Effort-reward Imbalance （ERI） model on the risk estimation of depression in humans in comparison with the effects when they are used respectively. Methods A total of 3 632 males and 1 706 females from 13 factories and companies in Henan province were recruited in this cross-sectional study. Perceived job stress was evaluated with the Job Content Questionnaire and Effort-Reward Imbalance Questionnaire （Chinese version）. Depressive symptoms were assessed by using the Center for Epidemiological Studies Depression Scale （CES-D）. Results DC （demands/job control ratio） and ERI were shown to be independently associated with depressive symptoms. The outcome of low social support and overcommitment were similar. High DC and low social support （SS）, high ERI and high overcommitment, and high DC and high ERI posed greater risks of depressive symptoms than each of them did alone. ERI model and SS model seem to be effective in estimating the risk of depressive symptoms if they are used respectively. Conclusion The DC had better performance when it was used in combination with low SS. The effect on physical demands was better than on psychological demands. The combination of DCS and ERI models could improve the risk estimate of depressive symptoms in humans.展开更多
Indoor CO2 concentration depends on the number of persons, their metabolic rates, other sources of indoor pollution, ventilation rate and ventilation efficiency. These factors are not considered by the Spanish technic...Indoor CO2 concentration depends on the number of persons, their metabolic rates, other sources of indoor pollution, ventilation rate and ventilation efficiency. These factors are not considered by the Spanish technical building code since ventilation is set only by a fixed air change rate. This paper aims to explore the possibilities of DCVS （demand controlled ventilation systems） to ensure adequate and sustainable ventilation. It is based on a research project carried out by the University of the Basque Country （EHU-UPV） and Euskadi Public Housing and Soil Join-Stock Company （VISESA）： the living rooms of 90 dwellings were provided with DCVS, where CO2 sensors were used to dynamically control the ventilation rate. Tests were carried out using tracer gas techniques, with results showing the air age to be adequate at every point of the occupied zones and free of stagnant areas, therefore proving the system＇s effectiveness and rapid response, and its energy savings.展开更多
Nowadays renewable energy has become a trend for energy production but its variable nature has made balancing of demand and supply of the power grid difficult. Dynamic demand management using smart appliances is propo...Nowadays renewable energy has become a trend for energy production but its variable nature has made balancing of demand and supply of the power grid difficult. Dynamic demand management using smart appliances is proposed to serve as a way that part of the regulation burden of balancing demand and supply is shifted to the demand side. However, if all appliances respond to the same frequency deviation, they may start to synchronize, causing large power overshoots and instability of the power grid. Therefore, the idea of implementing randomness into the frequency control of the appliances is proposed and this is what we call a stochastic approach. Simulators are built from scratch to model both scenarios. The effect of synchronization is analyzed and the parameters that can affect the synchronization are investigated. It has been found that the larger the contribution from the smart appliances to the power grid, the easier and faster the synchronization takes place. The stochastic approach solves the problem of synchronization and averages out the large power overshoot. However, the overall performance of stochastic operations is unacceptable due to the randomness in the operation though the mean and variance are as expected. More advanced feedback policies and schemes may be designed to achieve a better performance.展开更多
温控负荷(temperature control loads,TCLs)灵活性可行域的有效量化和聚合是其响应电价与调控信号的前提。由于TCLs能量在时间上耦合,且设备调节特性和物理参数各异,具有较高异质性,现有聚合方法面临计算复杂度高、适配性差等问题。该...温控负荷(temperature control loads,TCLs)灵活性可行域的有效量化和聚合是其响应电价与调控信号的前提。由于TCLs能量在时间上耦合,且设备调节特性和物理参数各异,具有较高异质性,现有聚合方法面临计算复杂度高、适配性差等问题。该文基于极端场景法建立了通用虚拟电池(virtual battery,VB)模型,即通过一套标准电池参数描述资源灵活性,其通用形式使得聚合可行域可以按一定规则线性求和获得。在此基础上,提出一种基于虚拟电池模型的外逼近闵可夫斯基聚合方法,并从数学上不失一般性地对不同异质性设备聚合的有效性进行了证明与推广。最后,提出了考虑系统灵活性供需平衡的负荷聚合商日前优化调度模型。算例结果表明,所提温控负荷可行域聚合方法在提高了外逼近精度的同时保证了较高的计算效率。相比传统模型,所提聚合模型有着更好的优化性能。展开更多
基金funded by Henan Provincial Health Science and Technology Key Projects(201001009)National Science and Technology Infrastructure Program(2006BAI06B 08),China
文摘Objective To investigate the co-effect of Demand-control-support （DCS） model and Effort-reward Imbalance （ERI） model on the risk estimation of depression in humans in comparison with the effects when they are used respectively. Methods A total of 3 632 males and 1 706 females from 13 factories and companies in Henan province were recruited in this cross-sectional study. Perceived job stress was evaluated with the Job Content Questionnaire and Effort-Reward Imbalance Questionnaire （Chinese version）. Depressive symptoms were assessed by using the Center for Epidemiological Studies Depression Scale （CES-D）. Results DC （demands/job control ratio） and ERI were shown to be independently associated with depressive symptoms. The outcome of low social support and overcommitment were similar. High DC and low social support （SS）, high ERI and high overcommitment, and high DC and high ERI posed greater risks of depressive symptoms than each of them did alone. ERI model and SS model seem to be effective in estimating the risk of depressive symptoms if they are used respectively. Conclusion The DC had better performance when it was used in combination with low SS. The effect on physical demands was better than on psychological demands. The combination of DCS and ERI models could improve the risk estimate of depressive symptoms in humans.
文摘Indoor CO2 concentration depends on the number of persons, their metabolic rates, other sources of indoor pollution, ventilation rate and ventilation efficiency. These factors are not considered by the Spanish technical building code since ventilation is set only by a fixed air change rate. This paper aims to explore the possibilities of DCVS （demand controlled ventilation systems） to ensure adequate and sustainable ventilation. It is based on a research project carried out by the University of the Basque Country （EHU-UPV） and Euskadi Public Housing and Soil Join-Stock Company （VISESA）： the living rooms of 90 dwellings were provided with DCVS, where CO2 sensors were used to dynamically control the ventilation rate. Tests were carried out using tracer gas techniques, with results showing the air age to be adequate at every point of the occupied zones and free of stagnant areas, therefore proving the system＇s effectiveness and rapid response, and its energy savings.
文摘Nowadays renewable energy has become a trend for energy production but its variable nature has made balancing of demand and supply of the power grid difficult. Dynamic demand management using smart appliances is proposed to serve as a way that part of the regulation burden of balancing demand and supply is shifted to the demand side. However, if all appliances respond to the same frequency deviation, they may start to synchronize, causing large power overshoots and instability of the power grid. Therefore, the idea of implementing randomness into the frequency control of the appliances is proposed and this is what we call a stochastic approach. Simulators are built from scratch to model both scenarios. The effect of synchronization is analyzed and the parameters that can affect the synchronization are investigated. It has been found that the larger the contribution from the smart appliances to the power grid, the easier and faster the synchronization takes place. The stochastic approach solves the problem of synchronization and averages out the large power overshoot. However, the overall performance of stochastic operations is unacceptable due to the randomness in the operation though the mean and variance are as expected. More advanced feedback policies and schemes may be designed to achieve a better performance.
文摘温控负荷(temperature control loads,TCLs)灵活性可行域的有效量化和聚合是其响应电价与调控信号的前提。由于TCLs能量在时间上耦合,且设备调节特性和物理参数各异,具有较高异质性,现有聚合方法面临计算复杂度高、适配性差等问题。该文基于极端场景法建立了通用虚拟电池(virtual battery,VB)模型,即通过一套标准电池参数描述资源灵活性,其通用形式使得聚合可行域可以按一定规则线性求和获得。在此基础上,提出一种基于虚拟电池模型的外逼近闵可夫斯基聚合方法,并从数学上不失一般性地对不同异质性设备聚合的有效性进行了证明与推广。最后,提出了考虑系统灵活性供需平衡的负荷聚合商日前优化调度模型。算例结果表明,所提温控负荷可行域聚合方法在提高了外逼近精度的同时保证了较高的计算效率。相比传统模型,所提聚合模型有着更好的优化性能。
