The reliability and availability of the reactor protection system （RPS） can be improved by using M out of N judg- ment system. By analyzing two quantitative indicators, the rate of refusal to operate and mal-operati...The reliability and availability of the reactor protection system （RPS） can be improved by using M out of N judg- ment system. By analyzing two quantitative indicators, the rate of refusal to operate and mal-operation rate, a strict math- ematical formula and an approximate calculation are stated. The differences of a series of judgment systems are discussed on condition that the unsafe failure probability and the security failure probability are both 0.1. Based on given parameters （A, B,P, Q）： A is upper limit of the refusal rate for the RPS, B is upper limit of the real-operation rate, P and Q are basic protection unit rates corresponding to refusal rate and mal-operation rate, respectively. According to these parameters, the values of N and M can be solved.展开更多
Long-term climatic data （maximum temperature, minimum temperature, rainfall and evaporation） for Big Bend in the Lowveld, a semi-arid region of Swaziland, were analysed for any changes or variations. Evaporation and...Long-term climatic data （maximum temperature, minimum temperature, rainfall and evaporation） for Big Bend in the Lowveld, a semi-arid region of Swaziland, were analysed for any changes or variations. Evaporation and rainfall data were analysed to assess water resources availability in the region. Analysis of the available data shows that there is no indication of decrease in rainfall with time, but the results show that there has been a steady increase in minimum temperatures over the last 25 years. The average effective water resources index, measured as the difference between mean annual rainfall and mean annual evaporation, for the region in the period from 1965 to 2001 was -1,500 mm. The large negative index implies low available water for the region, a situation that is likely to affect agricultural, hydropower and other water related development activities in the region. The negative effective water index implies deficits in the region＇s water resources which call for better management of the region＇s water resources. In the agriculture sector, this requires promoting technologies and practices that provide for water saving, improved water use performance and high water productivity. These include soil conservation tillage, wastewater reuse, runoff harvesting and soil fertility interventions through application of fertilizers, manures and mulches, and agronomic management. There is need for more analysis for the other regions in order to get a countrywide picture of the climate as well as water resources situations.展开更多
From the point of view of urban consumption behavior, urban fresh water consumption could be classified as three types, namely, direct, indirect and induced water consumption. A calculation approach of urban flesh wat...From the point of view of urban consumption behavior, urban fresh water consumption could be classified as three types, namely, direct, indirect and induced water consumption. A calculation approach of urban flesh water consumption was presented based on the theory of urban basic material consumption and the input-output method, which was utilized to calculate urban fresh water consumption of China, and to analyze its structural change and causes. The results show that the total urban flesh water consumption increased 561.7× 10^9m^3, and the proportion to the total national flesh water resources increased by 20 percentage points from 1952 to 2005. The proportion of direct and induced water consumption had been continuously rising, and it increased by 15 and 35 percentage points separately from 1952 to 2005, while the proportion of indirect water consumption decreased by 50 percentage points. Urban indi- rect water consumption was mainly related to urban grain, beef and mutton consumption, and urban induced water consumption had a close relationship with the amount of carbon emission per capita. Finally, some countermeasures were put forward to realize sustainable utilization of urban fresh water resources in China.展开更多
Service composition is considered to be an effective way for resource sharing and node collaboration in Mobile Ad hoc NETworks (MANETs) environment.In order to improve the reliability and shorten the response time of ...Service composition is considered to be an effective way for resource sharing and node collaboration in Mobile Ad hoc NETworks (MANETs) environment.In order to improve the reliability and shorten the response time of composite services,this paper first analyzes the node environments and network environments that affect the component services' availability,and then proposes an Environment-aware Quantitative Evaluation Model for Service Availability (EQEM-SA).In addition,based on EQEM-SA,a service field concept is proposed as well as the availability attenuation equation,where the availability value is considered as the field strength.Then the service selection approach based on service field model is presented.The effectiveness of the proposed approach is illustrated and compared with related references,and the results of experimental evaluations indicate that our approach significantly reduces the failure rate and shortens the service delay.展开更多
This study monitored the present status ofPenaeus monodon post larvae （PL.） of Kholpatua river in Satkhira. The survey was conducted in Kholpatua river from January 2014 to December 2014 and was compared with the te...This study monitored the present status ofPenaeus monodon post larvae （PL.） of Kholpatua river in Satkhira. The survey was conducted in Kholpatua river from January 2014 to December 2014 and was compared with the ten years old secondary data. The results showed that there was a 41.57% decrease in number of catches ofP. monodon PL. over the course of time from ten years ago to the year of 2014. Although the number of active fishermen＇s boats have increased from 250 to 360 in ten years. The study also showed that the severe shrimp seed collection activities reduced the availability ofP. monodon PL. at Satkhira district, which has a severe negative impact on the availability of total catches. To control such decrease of P. monodon PL. in Bangladesh, more intensive study should be done.展开更多
Peroral cholangioscopy was first described in 1970s and has recently gained popularity.Peroral cholangioscopy is appealing to therapeutic endoscopists because a direct intraluminal view of the biliary duct system offe...Peroral cholangioscopy was first described in 1970s and has recently gained popularity.Peroral cholangioscopy is appealing to therapeutic endoscopists because a direct intraluminal view of the biliary duct system offers possibilities for diagnosis and interventions beyond that which other imaging or endoscopic modalities can provide.As the image quality of cholangioscopies improves,so too does their diagnostic capability,and as their durability and maneuverability increases,so too does their potential use for therapeutic applications.This editorial is intended to provide a brief review of recent developments in peroral cholangioscopy and current indications for its use.展开更多
AIM: To investigate the liver stiffness measurement (LSM) applicability and variability with reference to three probe positions according to the region of liver biopsy. METHODS: The applicability for LSM was defined a...AIM: To investigate the liver stiffness measurement (LSM) applicability and variability with reference to three probe positions according to the region of liver biopsy. METHODS: The applicability for LSM was defined as at least 10 valid measurements with a success rate greater than 60% and an interquartile range/median LSM < 30%. The LSM variability compared the inter-position concordance and the concordance with FibroTest. RESULTS: Four hundred and forty two consecutive patients were included. The applicability of the anterior position (81%) was significantly higher than that of the reference (69%) and lower positions (68%), (both P = 0.0001). There was a signif icant difference (0.5 kPa, 95% CI 0.13-0.89; P < 0.0001) between mean LSM estimated at the reference position (9.3 kPa) vs the anterior position (8.8 kPa). Discordance between positions was associated with thoracic fold (P = 0.008). The discordance rate between the reference position result and FibroTest was higher when the 7.1 kPa cutoff was used to define advanced fibrosis instead of 8.8 kPa (33.6% vs 23.5%, P = 0.03).CONCLUSION: The anterior position of the probe should be the fi rst choice for LSM using Fibroscan, as it has a higher applicability without higher variability compared to the usual liver biopsy position.展开更多
Nine targets which stand both for the static characteristic of produced formations and the dynamic parameter of wells including the average permeability,variation coefficient of permeability,moving capability,remainin...Nine targets which stand both for the static characteristic of produced formations and the dynamic parameter of wells including the average permeability,variation coefficient of permeability,moving capability,remaining recoverable reserves,coefficient of flooding,daily oil production,increasing rate of water cut,cumulative liquid production per unit meter and efficiency index of oil production are selected as the evaluation indexes,a novel model to evaluate the porous formations in long-term waterflooding sand reservoir was established by using the support vector machine and clustering analysis. Data of 57 wells from Shentuo 21 block Shengli oilfield was analyzed by using the model. Four kinds of formation groups were gained. According to the analysis result,different adjustment solutions were put forward to develop the relevant formations. The Monthly oil production increased 7.6 % and the water cut decreased 8.9 % after the adjusted solutions. Good results indicate that the learning from this method gained will be valuable adding to other long-term waterflooding sand reservoirs in Shengli oilfield and other similar reservoirs worldwide.展开更多
In peer-assisted streaming network, service provider needs to pre-pushing resources to some users for caching. This scheme can increase the resource availability. In traditional strategy, in order to guarantee the use...In peer-assisted streaming network, service provider needs to pre-pushing resources to some users for caching. This scheme can increase the resource availability. In traditional strategy, in order to guarantee the user＇s quality of service （QoS）, the pre-pushing action can only start at the time point that the certain user has not used the computer for more than 20 minutes. If the user comes back, the pre-pushing action will be stopped. We claim that this is not an efficient scheme. In this paper, we propose a novel pre-pushing scheme to improve the pre-pushing efficiency, while meeting the user＇s QoS requirements. The basic idea is using the user＇s available bandwidth as much as possible in the condition of meeting the user＇s QoS requirements. Then we design an available bandwidth calculating strategy. The numerical simulation demonstrates that our proposed scheme outperforms the traditional one.展开更多
基金Research Project of Hunan Province Education Department(No.14C0972)
文摘The reliability and availability of the reactor protection system （RPS） can be improved by using M out of N judg- ment system. By analyzing two quantitative indicators, the rate of refusal to operate and mal-operation rate, a strict math- ematical formula and an approximate calculation are stated. The differences of a series of judgment systems are discussed on condition that the unsafe failure probability and the security failure probability are both 0.1. Based on given parameters （A, B,P, Q）： A is upper limit of the refusal rate for the RPS, B is upper limit of the real-operation rate, P and Q are basic protection unit rates corresponding to refusal rate and mal-operation rate, respectively. According to these parameters, the values of N and M can be solved.
文摘Long-term climatic data （maximum temperature, minimum temperature, rainfall and evaporation） for Big Bend in the Lowveld, a semi-arid region of Swaziland, were analysed for any changes or variations. Evaporation and rainfall data were analysed to assess water resources availability in the region. Analysis of the available data shows that there is no indication of decrease in rainfall with time, but the results show that there has been a steady increase in minimum temperatures over the last 25 years. The average effective water resources index, measured as the difference between mean annual rainfall and mean annual evaporation, for the region in the period from 1965 to 2001 was -1,500 mm. The large negative index implies low available water for the region, a situation that is likely to affect agricultural, hydropower and other water related development activities in the region. The negative effective water index implies deficits in the region＇s water resources which call for better management of the region＇s water resources. In the agriculture sector, this requires promoting technologies and practices that provide for water saving, improved water use performance and high water productivity. These include soil conservation tillage, wastewater reuse, runoff harvesting and soil fertility interventions through application of fertilizers, manures and mulches, and agronomic management. There is need for more analysis for the other regions in order to get a countrywide picture of the climate as well as water resources situations.
基金Under the auspices of Key Project of National Natural Science Foundation of China (No. 40535026)
文摘From the point of view of urban consumption behavior, urban fresh water consumption could be classified as three types, namely, direct, indirect and induced water consumption. A calculation approach of urban flesh water consumption was presented based on the theory of urban basic material consumption and the input-output method, which was utilized to calculate urban fresh water consumption of China, and to analyze its structural change and causes. The results show that the total urban flesh water consumption increased 561.7× 10^9m^3, and the proportion to the total national flesh water resources increased by 20 percentage points from 1952 to 2005. The proportion of direct and induced water consumption had been continuously rising, and it increased by 15 and 35 percentage points separately from 1952 to 2005, while the proportion of indirect water consumption decreased by 50 percentage points. Urban indi- rect water consumption was mainly related to urban grain, beef and mutton consumption, and urban induced water consumption had a close relationship with the amount of carbon emission per capita. Finally, some countermeasures were put forward to realize sustainable utilization of urban fresh water resources in China.
基金supported in part by the National Key Basic Research Program of China(Grant Nos.2009CB320406and2009CB320504)Foundation for Innovative Research Groups of the National Natural Science Foundation of China(Grant No.60821001)National Natural Science Foundation of China(Grant No.61070206)
文摘Service composition is considered to be an effective way for resource sharing and node collaboration in Mobile Ad hoc NETworks (MANETs) environment.In order to improve the reliability and shorten the response time of composite services,this paper first analyzes the node environments and network environments that affect the component services' availability,and then proposes an Environment-aware Quantitative Evaluation Model for Service Availability (EQEM-SA).In addition,based on EQEM-SA,a service field concept is proposed as well as the availability attenuation equation,where the availability value is considered as the field strength.Then the service selection approach based on service field model is presented.The effectiveness of the proposed approach is illustrated and compared with related references,and the results of experimental evaluations indicate that our approach significantly reduces the failure rate and shortens the service delay.
文摘This study monitored the present status ofPenaeus monodon post larvae （PL.） of Kholpatua river in Satkhira. The survey was conducted in Kholpatua river from January 2014 to December 2014 and was compared with the ten years old secondary data. The results showed that there was a 41.57% decrease in number of catches ofP. monodon PL. over the course of time from ten years ago to the year of 2014. Although the number of active fishermen＇s boats have increased from 250 to 360 in ten years. The study also showed that the severe shrimp seed collection activities reduced the availability ofP. monodon PL. at Satkhira district, which has a severe negative impact on the availability of total catches. To control such decrease of P. monodon PL. in Bangladesh, more intensive study should be done.
文摘Peroral cholangioscopy was first described in 1970s and has recently gained popularity.Peroral cholangioscopy is appealing to therapeutic endoscopists because a direct intraluminal view of the biliary duct system offers possibilities for diagnosis and interventions beyond that which other imaging or endoscopic modalities can provide.As the image quality of cholangioscopies improves,so too does their diagnostic capability,and as their durability and maneuverability increases,so too does their potential use for therapeutic applications.This editorial is intended to provide a brief review of recent developments in peroral cholangioscopy and current indications for its use.
文摘AIM: To investigate the liver stiffness measurement (LSM) applicability and variability with reference to three probe positions according to the region of liver biopsy. METHODS: The applicability for LSM was defined as at least 10 valid measurements with a success rate greater than 60% and an interquartile range/median LSM < 30%. The LSM variability compared the inter-position concordance and the concordance with FibroTest. RESULTS: Four hundred and forty two consecutive patients were included. The applicability of the anterior position (81%) was significantly higher than that of the reference (69%) and lower positions (68%), (both P = 0.0001). There was a signif icant difference (0.5 kPa, 95% CI 0.13-0.89; P < 0.0001) between mean LSM estimated at the reference position (9.3 kPa) vs the anterior position (8.8 kPa). Discordance between positions was associated with thoracic fold (P = 0.008). The discordance rate between the reference position result and FibroTest was higher when the 7.1 kPa cutoff was used to define advanced fibrosis instead of 8.8 kPa (33.6% vs 23.5%, P = 0.03).CONCLUSION: The anterior position of the probe should be the fi rst choice for LSM using Fibroscan, as it has a higher applicability without higher variability compared to the usual liver biopsy position.
基金supported by funds from the Key Pro-ject of Chinese National Programs for Fundamental Research and Development (863 Program) under thenumber 2007AA090701the Young and Mid-dle-aged Researchers Innovation and Technology Foun-dation of CNPC under the number 04E7029
文摘Nine targets which stand both for the static characteristic of produced formations and the dynamic parameter of wells including the average permeability,variation coefficient of permeability,moving capability,remaining recoverable reserves,coefficient of flooding,daily oil production,increasing rate of water cut,cumulative liquid production per unit meter and efficiency index of oil production are selected as the evaluation indexes,a novel model to evaluate the porous formations in long-term waterflooding sand reservoir was established by using the support vector machine and clustering analysis. Data of 57 wells from Shentuo 21 block Shengli oilfield was analyzed by using the model. Four kinds of formation groups were gained. According to the analysis result,different adjustment solutions were put forward to develop the relevant formations. The Monthly oil production increased 7.6 % and the water cut decreased 8.9 % after the adjusted solutions. Good results indicate that the learning from this method gained will be valuable adding to other long-term waterflooding sand reservoirs in Shengli oilfield and other similar reservoirs worldwide.
基金the National Natural Science Foundation of China under Grant No.61202079,61308018，the China Postdoctoral Science Foundation under Grant No.2014T70031，the Fundamental Research Funds for the Central Universities under Grant No.FRF-TP-14-046A2
文摘In peer-assisted streaming network, service provider needs to pre-pushing resources to some users for caching. This scheme can increase the resource availability. In traditional strategy, in order to guarantee the user＇s quality of service （QoS）, the pre-pushing action can only start at the time point that the certain user has not used the computer for more than 20 minutes. If the user comes back, the pre-pushing action will be stopped. We claim that this is not an efficient scheme. In this paper, we propose a novel pre-pushing scheme to improve the pre-pushing efficiency, while meeting the user＇s QoS requirements. The basic idea is using the user＇s available bandwidth as much as possible in the condition of meeting the user＇s QoS requirements. Then we design an available bandwidth calculating strategy. The numerical simulation demonstrates that our proposed scheme outperforms the traditional one.
