Aim To determine the global optimal solution for a mine ventilation network under given network topology and airway characteristics. Methods\ The genetic algorithm was used to find the global optimal solution of the ...Aim To determine the global optimal solution for a mine ventilation network under given network topology and airway characteristics. Methods\ The genetic algorithm was used to find the global optimal solution of the network. Results\ A modified genetic algorithm is presented with its characteristics and principle. Instead of working on the conventional bit by bit operation, both the crossover and mutation operators are handled in real values by the proposed algorithms. To prevent the system from turning into a premature problem, the elitists from two groups of possible solutions are selected to reproduce the new populations. Conclusion\ The simulation results show that the method outperforms the conventional nonlinear programming approach whether from the viewpoint of the number of iterations required to find the optimum solutions or from the final solutions obtained.展开更多
In large mines,single fan is usually not enough to ventilate all the working areas.Single mine-fan approach cannot be directly applied to multiple-fan networks because the present of multiple pressures and air quantit...In large mines,single fan is usually not enough to ventilate all the working areas.Single mine-fan approach cannot be directly applied to multiple-fan networks because the present of multiple pressures and air quantities associated with each fan in the network.Accordingly,each fan in a multiple-fan system has its own mine characteristic curve,or a subsystem curve.Under some consideration,the conventional concept of a mine characteristic curve of a single-fan system can be directly extended to that of a particular fan within a multiple-fan system.In this paper the mutual effect of the fans on each other and their effect on the stability of the ventilation network were investigated by Hardy Cross algorithm combined with a switching-parameters technique.To show the validity and reliability of this algorithm,the stability of the ventilation system of Abu-Tartur Mine(one of the largest underground mine in Egypt)has been studied.展开更多
According to the nonlinear and time dependent features of the ventilation systems for coal mines, a neural network method is applied to control the ventilator for coal mines in real time. The technical processes of co...According to the nonlinear and time dependent features of the ventilation systems for coal mines, a neural network method is applied to control the ventilator for coal mines in real time. The technical processes of coal mine ventilation system are introduced, and the principle of controlling a ventilation fan is also explained in detail. The artificial neutral network method is used to calculate the wind quantity needed by work spots in coal mine on the basis of the data collected by the system, including ventilation conditions, environmental temperatures, humidity, coal dust and the contents of all kinds of poisonous and harmful gases. Then the speed of ventilation fan is controlled according to the required wind which is determined by an overall integration of data. A neural network method is presented for overall optimized solution or the genetic algorithm of simulated annealing.展开更多
In underground constructions, a good ventilation design not only delivers fresh air to establish good working environment, but also provides a scientific and reliable basis to prevent disasters. In emergency cases, un...In underground constructions, a good ventilation design not only delivers fresh air to establish good working environment, but also provides a scientific and reliable basis to prevent disasters. In emergency cases, unexpected closure of the main airways may occur, providing the workers with alternative airways is substantial. This is important not only to sustain personnel lives, but also to prevent the mine ventilation system from damage. In this research, alternate solutions were introduced in case of failure in the underground construction to keep a pre-assigned fixed quantity in a working place for mine ventilation network. Eight different collapse scenarios were proposed to study their effect on the air quantity distribution among the branches in the ventilation circuit. From these scenarios, it is found that providing a sufficient air quantity in the working places could be achieved through modification of the network topology and adjusting the values of the regulators pressure. It is also indicated that the distance between the collapse and working places has a great effect on the amount of air delivered to it. A reduction in the power consumption could be done by re-arrange the installed regulators and decreasing the number of nodes and branches inside the network. A relationship representing the effect of changing the network topology on the total network power consumption was deduced through regression analysis. It is found that the total network power is quadratic dependent on the number of regulators and number of branches while it is directly dependent on the regulator power.展开更多
In mine ventilation network calculation, the total ventilatiou perameters, such as total specific resistance and total natural veutilatiou pressure of an overall mine ventilation system, play an important role on sele...In mine ventilation network calculation, the total ventilatiou perameters, such as total specific resistance and total natural veutilatiou pressure of an overall mine ventilation system, play an important role on selecting main fan and regulating its operating point. This paper explains the critical effect of network’ s total parameter calculation on the above two aspects and presents a new method, the junction pressure composing method(JPC method), which can be applied to calculate the total resistance.of an overall, complex and multi-fan ventilation network. Based on the total ressistance and airflow rate of main fan, total specific resistance of a natwork is easily calculated. This method gets rid of those shortcomings in the route airflow working mathod(RAW method), greatly improves computing speed and adaptability, and can calculate the total parameters of a mine ventilation network rapidly and conveniently. This method is proved to be correct and reliable by example tests.展开更多
This paper constructed the mine ventilation network model using the powerful function of attribute management and display of GIS based on the study of GIS and mine ventilation network. In a mine ventilation network, a...This paper constructed the mine ventilation network model using the powerful function of attribute management and display of GIS based on the study of GIS and mine ventilation network. In a mine ventilation network, a specified result can be obtained by defining weight values for attribute fields as the constraint condition. It is of great importance for mines to determine the best rescue and leaving route by the analyses of mine ventilation network routes, nodes and loops when a mine accident happens.展开更多
The stability of branched airflow of ventilation network is guarantee of safety in production of coal mine. Two indexes which stand for the stability of branches of ventilation network in coal mine were put forward in...The stability of branched airflow of ventilation network is guarantee of safety in production of coal mine. Two indexes which stand for the stability of branches of ventilation network in coal mine were put forward in this paper, that are airflow intensity and sta- bility index of branched airflow, The airflow stability of working place was divided into different grade according to the stability index. The conclusion has great significance for safety in production of coal mine.展开更多
In order to overcome the disadvantages of diagonal connection structures that are complex and for which it is difficult to derive the discriminant of the airflow directions of airways, we have applied a multiple regre...In order to overcome the disadvantages of diagonal connection structures that are complex and for which it is difficult to derive the discriminant of the airflow directions of airways, we have applied a multiple regression method to analyze the effect, of changing the rules of mine airflows, on the stability of a mine ventilation system. The amount of air （ Qj ） is determined for the major airway and an optimum regression equation was derived for Qi as a function of the independent variable （ Ri ）, i.e., the venti- lation resistance between different airways. Therefore, corresponding countermeasures are proposed according to the changes in airflows. The calculated results agree very well with our practical situation, indicating that multiple regression analysis is simple, quick and practical and is therefore an effective method to analyze the stability of mine ventilation systems.展开更多
The calculating methods for path number and path matrix of ventilation net- works without unidirectional circuits were introduced,and the inapplicability problem of the matrix algorithm to determine paths in a ventila...The calculating methods for path number and path matrix of ventilation net- works without unidirectional circuits were introduced,and the inapplicability problem of the matrix algorithm to determine paths in a ventilation network with unidirectional circuit was brought forward,and a depth-first search method based algorithm to determine path ma- trix by means of modifying search strategies was discussed.The method is suitable for ventilation networks with unidirectional circuits and ventilation networks without unidirec- tional circuits,moreover the complexity is less than the complexities of matrix based algo- rithms.A series of methods and means to avoid and to reduce the negative effects of un- idirectional circuits such as the optimum of the positions of fan stations,the increase or de-crease of fan station numbers,the optimum regulation of network and the analysis of diagonal structures were put forward.展开更多
The stability of ventilation system includes stabilities of branch, network and main fan. The ventilation system is a dynamic process. The parameters in the ventilation system vary with time. In the paper, a group of ...The stability of ventilation system includes stabilities of branch, network and main fan. The ventilation system is a dynamic process. The parameters in the ventilation system vary with time. In the paper, a group of mathematical models of quantitative analysis are set up, and the mathematical models are suitable to any ventilation system.展开更多
Ventilation characteristic parameters are the base of ventilation network solution; however, they are apt to be affected by operating errors, reading errors, airflow stability, and other factors, and it is difficult t...Ventilation characteristic parameters are the base of ventilation network solution; however, they are apt to be affected by operating errors, reading errors, airflow stability, and other factors, and it is difficult to obtain accurate results. In order to check the ventilation characteristic parameters of mines more accurately, the integrated method of circuit and path is adopted to overcome the drawbacks caused by the traditional path method or circuit method in the digital debugging process of ventilation system, which can improve the large local error or the inconsistency between the airflow direction and the actual situation caused by inaccuracy of the ventilation characteristic parameters or checking in the ventilation network solution. The results show that this method can effectively reduce the local error and prevent the pseudo-airflow reversal phenomenon; in addition, the solution results are consistent with the actual situation of mines, and the effect is obvious.展开更多
This paper systematically introduced the method of direct, indirect and free-network adjustments and their application in data process of minewide ventilation measurements. The direct adjustment is suitable for errors...This paper systematically introduced the method of direct, indirect and free-network adjustments and their application in data process of minewide ventilation measurements. The direct adjustment is suitable for errors collating of the measurements of airflow rates. The indirect method is suitable for the adjustment of ventilation resistance. The free-net method is adapted to the combined adjustment of the measurements of both the ventilation in branches of the air network and the air pressure at nodes of the ventilation network, the partial adjustment is also introduced here to be used for saving the storage locations in computer required for the adjustment for large scale mine ventilation measurements.展开更多
Solar chimneys are renewable energy systems designed to enhance natural ventilation,improving thermal comfort in buildings.As passive systems,solar chimneys contribute to energy efficiency in a sustainable and environ...Solar chimneys are renewable energy systems designed to enhance natural ventilation,improving thermal comfort in buildings.As passive systems,solar chimneys contribute to energy efficiency in a sustainable and environmentally friendly way.The effectiveness of a solar chimney depends on its design and orientation relative to the cardinal directions,both of which are critical for optimal performance.This article presents a supervised learning approach using artificial neural networks to forecast the performance indicators of solar chimneys.Thedataset includes information from 2784 solar chimney configurations,which encompasses various factors such as chimney height,channel thickness,glass thickness,paint,wall material,measurement date,and orientation.The case study examines the four cardinal orientations and weather data from Mexico City,covering the period from 01 January to 31 December 2024.The main results indicate that the proposed artificial neural network models achieved higher coefficient of determination values(0.905-0.990)than the baseline method across performance indicators of the solar chimney system,demonstrating greater accuracy and improved generalization.The proposed approach highlights the potential of using artificial neural networks as a decision-making tool in the design stage of solar chimneys in sustainable architecture.展开更多
In the goal optimization and control optimization process the problems with common artificial neural network algorithm are unsure convergence, insufficient post-training network precision, and slow training speed, in ...In the goal optimization and control optimization process the problems with common artificial neural network algorithm are unsure convergence, insufficient post-training network precision, and slow training speed, in which partial minimum value question tends to occur. This paper conducted an in-depth study on the causes of the limi-tations of the algorithm, presented a rapid artificial neural network algorithm, which is characterized by integrating multiple algorithms and by using their complementary advan-tages. The salient feature of the method is self-organization, which can effectively prevent the optimized results from tending to be partial minimum values. Overall optimization can be achieved with this method, goal function can be searched for in overall scope. With op-timization control of coal mine ventilator as a practical application, the paper proves that by integrating multiple artificial neural network algorithms, best control optimization and goal optimized can be achieved.展开更多
In order to know the ventilating capacity of imperial smelt furnace(ISF), and increase the output of plumbum, an intelligent modeling method based on gray theory and artificial neural networks(ANN) is proposed, in whi...In order to know the ventilating capacity of imperial smelt furnace(ISF), and increase the output of plumbum, an intelligent modeling method based on gray theory and artificial neural networks(ANN) is proposed, in which the weight values in the integrated model can be adjusted automatically. An intelligent predictive model of the ventilating capacity of the ISF is established and analyzed by the method. The simulation results and industrial applications demonstrate that the predictive model is close to the real plant, the relative predictive error is 0.72%, which is 50% less than the single model, leading to a notable increase of the output of plumbum.展开更多
Successful weaning from ventilator play a critical role in improving the prognosis of patients who are treated in the intensive care unit(ICU).Several spontaneous breath trials(SBTs)have been developed to evaluate the...Successful weaning from ventilator play a critical role in improving the prognosis of patients who are treated in the intensive care unit(ICU).Several spontaneous breath trials(SBTs)have been developed to evaluate the ability of an individual patient to remain spontaneous breathing after disconnecting mechanical ventilation.However,it remains unclear which SBT techniques should be preferentially taken into consideration for critically ill patients receiving ventilator.We performed this network meta-analysis to investigate the comparative efficacy of all common SBTs and then found that automatic tube compensation(ATC)was better than others in increasing initial SBTsuccess rate and successful weaning rate.Therefore,ATC should be optimally considered to assess the ability of liberating ventilator in critical ill.展开更多
文摘Aim To determine the global optimal solution for a mine ventilation network under given network topology and airway characteristics. Methods\ The genetic algorithm was used to find the global optimal solution of the network. Results\ A modified genetic algorithm is presented with its characteristics and principle. Instead of working on the conventional bit by bit operation, both the crossover and mutation operators are handled in real values by the proposed algorithms. To prevent the system from turning into a premature problem, the elitists from two groups of possible solutions are selected to reproduce the new populations. Conclusion\ The simulation results show that the method outperforms the conventional nonlinear programming approach whether from the viewpoint of the number of iterations required to find the optimum solutions or from the final solutions obtained.
文摘In large mines,single fan is usually not enough to ventilate all the working areas.Single mine-fan approach cannot be directly applied to multiple-fan networks because the present of multiple pressures and air quantities associated with each fan in the network.Accordingly,each fan in a multiple-fan system has its own mine characteristic curve,or a subsystem curve.Under some consideration,the conventional concept of a mine characteristic curve of a single-fan system can be directly extended to that of a particular fan within a multiple-fan system.In this paper the mutual effect of the fans on each other and their effect on the stability of the ventilation network were investigated by Hardy Cross algorithm combined with a switching-parameters technique.To show the validity and reliability of this algorithm,the stability of the ventilation system of Abu-Tartur Mine(one of the largest underground mine in Egypt)has been studied.
文摘According to the nonlinear and time dependent features of the ventilation systems for coal mines, a neural network method is applied to control the ventilator for coal mines in real time. The technical processes of coal mine ventilation system are introduced, and the principle of controlling a ventilation fan is also explained in detail. The artificial neutral network method is used to calculate the wind quantity needed by work spots in coal mine on the basis of the data collected by the system, including ventilation conditions, environmental temperatures, humidity, coal dust and the contents of all kinds of poisonous and harmful gases. Then the speed of ventilation fan is controlled according to the required wind which is determined by an overall integration of data. A neural network method is presented for overall optimized solution or the genetic algorithm of simulated annealing.
文摘In underground constructions, a good ventilation design not only delivers fresh air to establish good working environment, but also provides a scientific and reliable basis to prevent disasters. In emergency cases, unexpected closure of the main airways may occur, providing the workers with alternative airways is substantial. This is important not only to sustain personnel lives, but also to prevent the mine ventilation system from damage. In this research, alternate solutions were introduced in case of failure in the underground construction to keep a pre-assigned fixed quantity in a working place for mine ventilation network. Eight different collapse scenarios were proposed to study their effect on the air quantity distribution among the branches in the ventilation circuit. From these scenarios, it is found that providing a sufficient air quantity in the working places could be achieved through modification of the network topology and adjusting the values of the regulators pressure. It is also indicated that the distance between the collapse and working places has a great effect on the amount of air delivered to it. A reduction in the power consumption could be done by re-arrange the installed regulators and decreasing the number of nodes and branches inside the network. A relationship representing the effect of changing the network topology on the total network power consumption was deduced through regression analysis. It is found that the total network power is quadratic dependent on the number of regulators and number of branches while it is directly dependent on the regulator power.
文摘In mine ventilation network calculation, the total ventilatiou perameters, such as total specific resistance and total natural veutilatiou pressure of an overall mine ventilation system, play an important role on selecting main fan and regulating its operating point. This paper explains the critical effect of network’ s total parameter calculation on the above two aspects and presents a new method, the junction pressure composing method(JPC method), which can be applied to calculate the total resistance.of an overall, complex and multi-fan ventilation network. Based on the total ressistance and airflow rate of main fan, total specific resistance of a natwork is easily calculated. This method gets rid of those shortcomings in the route airflow working mathod(RAW method), greatly improves computing speed and adaptability, and can calculate the total parameters of a mine ventilation network rapidly and conveniently. This method is proved to be correct and reliable by example tests.
文摘This paper constructed the mine ventilation network model using the powerful function of attribute management and display of GIS based on the study of GIS and mine ventilation network. In a mine ventilation network, a specified result can be obtained by defining weight values for attribute fields as the constraint condition. It is of great importance for mines to determine the best rescue and leaving route by the analyses of mine ventilation network routes, nodes and loops when a mine accident happens.
文摘The stability of branched airflow of ventilation network is guarantee of safety in production of coal mine. Two indexes which stand for the stability of branches of ventilation network in coal mine were put forward in this paper, that are airflow intensity and sta- bility index of branched airflow, The airflow stability of working place was divided into different grade according to the stability index. The conclusion has great significance for safety in production of coal mine.
基金Project F010206 supported by the National Natural Science Foundation of China
文摘In order to overcome the disadvantages of diagonal connection structures that are complex and for which it is difficult to derive the discriminant of the airflow directions of airways, we have applied a multiple regression method to analyze the effect, of changing the rules of mine airflows, on the stability of a mine ventilation system. The amount of air （ Qj ） is determined for the major airway and an optimum regression equation was derived for Qi as a function of the independent variable （ Ri ）, i.e., the venti- lation resistance between different airways. Therefore, corresponding countermeasures are proposed according to the changes in airflows. The calculated results agree very well with our practical situation, indicating that multiple regression analysis is simple, quick and practical and is therefore an effective method to analyze the stability of mine ventilation systems.
文摘The calculating methods for path number and path matrix of ventilation net- works without unidirectional circuits were introduced,and the inapplicability problem of the matrix algorithm to determine paths in a ventilation network with unidirectional circuit was brought forward,and a depth-first search method based algorithm to determine path ma- trix by means of modifying search strategies was discussed.The method is suitable for ventilation networks with unidirectional circuits and ventilation networks without unidirec- tional circuits,moreover the complexity is less than the complexities of matrix based algo- rithms.A series of methods and means to avoid and to reduce the negative effects of un- idirectional circuits such as the optimum of the positions of fan stations,the increase or de-crease of fan station numbers,the optimum regulation of network and the analysis of diagonal structures were put forward.
文摘The stability of ventilation system includes stabilities of branch, network and main fan. The ventilation system is a dynamic process. The parameters in the ventilation system vary with time. In the paper, a group of mathematical models of quantitative analysis are set up, and the mathematical models are suitable to any ventilation system.
基金Supported by the National Natural Science Foundation of China （61772159）
文摘Ventilation characteristic parameters are the base of ventilation network solution; however, they are apt to be affected by operating errors, reading errors, airflow stability, and other factors, and it is difficult to obtain accurate results. In order to check the ventilation characteristic parameters of mines more accurately, the integrated method of circuit and path is adopted to overcome the drawbacks caused by the traditional path method or circuit method in the digital debugging process of ventilation system, which can improve the large local error or the inconsistency between the airflow direction and the actual situation caused by inaccuracy of the ventilation characteristic parameters or checking in the ventilation network solution. The results show that this method can effectively reduce the local error and prevent the pseudo-airflow reversal phenomenon; in addition, the solution results are consistent with the actual situation of mines, and the effect is obvious.
文摘This paper systematically introduced the method of direct, indirect and free-network adjustments and their application in data process of minewide ventilation measurements. The direct adjustment is suitable for errors collating of the measurements of airflow rates. The indirect method is suitable for the adjustment of ventilation resistance. The free-net method is adapted to the combined adjustment of the measurements of both the ventilation in branches of the air network and the air pressure at nodes of the ventilation network, the partial adjustment is also introduced here to be used for saving the storage locations in computer required for the adjustment for large scale mine ventilation measurements.
文摘Solar chimneys are renewable energy systems designed to enhance natural ventilation,improving thermal comfort in buildings.As passive systems,solar chimneys contribute to energy efficiency in a sustainable and environmentally friendly way.The effectiveness of a solar chimney depends on its design and orientation relative to the cardinal directions,both of which are critical for optimal performance.This article presents a supervised learning approach using artificial neural networks to forecast the performance indicators of solar chimneys.Thedataset includes information from 2784 solar chimney configurations,which encompasses various factors such as chimney height,channel thickness,glass thickness,paint,wall material,measurement date,and orientation.The case study examines the four cardinal orientations and weather data from Mexico City,covering the period from 01 January to 31 December 2024.The main results indicate that the proposed artificial neural network models achieved higher coefficient of determination values(0.905-0.990)than the baseline method across performance indicators of the solar chimney system,demonstrating greater accuracy and improved generalization.The proposed approach highlights the potential of using artificial neural networks as a decision-making tool in the design stage of solar chimneys in sustainable architecture.
基金Supported by the Science Foundation of the Liaoning Province(2004C011)
文摘In the goal optimization and control optimization process the problems with common artificial neural network algorithm are unsure convergence, insufficient post-training network precision, and slow training speed, in which partial minimum value question tends to occur. This paper conducted an in-depth study on the causes of the limi-tations of the algorithm, presented a rapid artificial neural network algorithm, which is characterized by integrating multiple algorithms and by using their complementary advan-tages. The salient feature of the method is self-organization, which can effectively prevent the optimized results from tending to be partial minimum values. Overall optimization can be achieved with this method, goal function can be searched for in overall scope. With op-timization control of coal mine ventilator as a practical application, the paper proves that by integrating multiple artificial neural network algorithms, best control optimization and goal optimized can be achieved.
文摘In order to know the ventilating capacity of imperial smelt furnace(ISF), and increase the output of plumbum, an intelligent modeling method based on gray theory and artificial neural networks(ANN) is proposed, in which the weight values in the integrated model can be adjusted automatically. An intelligent predictive model of the ventilating capacity of the ISF is established and analyzed by the method. The simulation results and industrial applications demonstrate that the predictive model is close to the real plant, the relative predictive error is 0.72%, which is 50% less than the single model, leading to a notable increase of the output of plumbum.
文摘Successful weaning from ventilator play a critical role in improving the prognosis of patients who are treated in the intensive care unit(ICU).Several spontaneous breath trials(SBTs)have been developed to evaluate the ability of an individual patient to remain spontaneous breathing after disconnecting mechanical ventilation.However,it remains unclear which SBT techniques should be preferentially taken into consideration for critically ill patients receiving ventilator.We performed this network meta-analysis to investigate the comparative efficacy of all common SBTs and then found that automatic tube compensation(ATC)was better than others in increasing initial SBTsuccess rate and successful weaning rate.Therefore,ATC should be optimally considered to assess the ability of liberating ventilator in critical ill.
