A model of continuous-time insider trading in which a risk-neutral in-sider possesses two imperfect correlated signals of a risky asset is studied.By conditional expectation theory and filtering theory,we first establ...A model of continuous-time insider trading in which a risk-neutral in-sider possesses two imperfect correlated signals of a risky asset is studied.By conditional expectation theory and filtering theory,we first establish three lemmas:normal corre-lation,equivalent pricing and equivalent profit,which can guarantee to turn our model into a model with insider knowing full information.Then we investigate the impact of the two correlated signals on the market equilibrium consisting of optimal insider trading strategy and semi-strong pricing rule.It shows that in the equilibrium,(1)the market depth is constant over time;(2)if the two noisy signals are not linerly correlated,then all private information of the insider is incorporated into prices in the end while the whole information on the asset value can not incorporated into prices in the end;(3)if the two noisy signals are linear correlated such that the insider can infer the whole information of the asset value,then our model turns into a model with insider knowing full information;(4)if the two noisy signals are the same then the total ex ant profit of the insider is increasing with the noise decreasing,while down to O as the noise going up to infinity;(5)if the two noisy signals are not linear correlated then with one noisy signal fixed,the total ex ante profit of the insider is single-peaked with a unique minimum with respect to the other noisy signal value,and furthermore as the noisy value going to O it gets its maximum,the profit in the case that the real value is observed.展开更多
[Objective] The study was to explore the major factors affecting diary cattle brucellosis risk assessment,as well as their strong-to-weak sequence,so as to provide theoretical basis for assessing diary cattle brucello...[Objective] The study was to explore the major factors affecting diary cattle brucellosis risk assessment,as well as their strong-to-weak sequence,so as to provide theoretical basis for assessing diary cattle brucellosis risk level in different regions.[Method] From 4 dimensions of feeding and importing,breeding,housing and polyculture situation,an evaluation index system was set up,and diary cattle brucellosis risk survey was conducted in 3 typical regions.Finally,systematic multilevel grey relation entropy method was applied to perform data analysis.[Result] The strong-to-weak sequence of Level 1 impact factor of diary cattle brucellosis was as follows：feeding and importinghousingpolyculture situationbreeding;the sequence of Level 2 impact factor was U32〉U12〉U11〉U31〉U21〉U42〉U43〉U23〉U22〉U41;the risk level sequence of 3 typical regions was Province A（County A1,A2,A3）Province B（County B1,B2,B3）Province C（County C1,C2,C3）.[Conclusion] According to the weight of Level 1 index strata,administrative departments at all levels and dairy cattle farmers should lay emphasis on the aspects of feeding,importing and housing;viewed from the perspective of Level 2 index strata,dairy cattle farmers should value the siting of cattle field,the brucellosis surveillance before importing and milking modes most.According to the diary cattle brucellosis risk level of 3 typical regions,if administrative departments at all levels strengthen peoples＇ awareness of their personal health and increase investment in this area,with new healthy cultured atmosphere built,the risk level of diary cattle brucellosis will surly decline.展开更多
Objective Several studies have examined the relationships between dietary potassium and sodium and hypertension, but few have evaluated the association between serum potassium or sodium and risk of incident hypertensi...Objective Several studies have examined the relationships between dietary potassium and sodium and hypertension, but few have evaluated the association between serum potassium or sodium and risk of incident hypertension. We therefore investigated the associations between serum potassium and sodium and risk of incident hypertension in a Chinese community-based population. Methods A total of 839 normotensive individuals without cardiovascular disease from the Chinese Multi-Provincial Cohort Study who took part in the baseline examination in 2007-2008 and the follow-up survey in 2012-2013 were included in this study. Odds ratios （OR） and 95% confidence intervals （95%CI） for baseline serum potassium and sodium in relation to the risk of new-onset hypertension were evaluated using multivari- ate logistic regression models. Results During five years of follow-up, 218 （26.0%） individuals progressed to hypertension. Logistic re- gression adjusting for multiple confounders showed that every 1 mEq/L increment in baseline serum potassium level was associated with a 75% increased risk of hypertension （OR： 1.75; 95%CI： 1.01-3.04; P = 0.04）. Compared with adults with serum potassium level of 4.20-4.79 mEq/L, adults with level 〉 4.80 mEq/L had an 84% increased risk of hypertension （OR： 1.84; 95%CI： 1.14-2.96; P = 0.01）. There was no significant association between serum sodium and risk of hypertension （OR： 0.96; 95%CI： 0.89-1.04; P = 0.33）. Conclusions Base- line serum potassium level, but not baseline serum sodium level, was positively related to the risk of incident hypertension in the Chinese population.展开更多
Purpose： The aims of this study were to assess differences of limb symmetry index （LSI） in strength- and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related pe...Purpose： The aims of this study were to assess differences of limb symmetry index （LSI） in strength- and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related performance levels and to prospectively assess limb differences as a possible risk factor for traumatic and overuse injury in youth ski racers. Methods： The study （Study 1） included 285 high-level competitive ski racers （125 females, 160 males） of 3 age-related performance levels and based on the school system： 95 youth （10-14 years, secondary modem school）, 107 adolescent （15-19 years, grammar school）, and 83 elite athletes （20-34 years）. To investigate the second aim （Study 2）, 67 of the 95 youth athletes were included and any traumatic or overuse injuries were prospectively recorded over 2 seasons. All athletes performed 4 unilateral tests （strength related： one-leg counter movement jump （OL-CMJ） and one-leg isometric/isokinetic press strength test （OL-ILS）; coordination related： one-leg stability test （OL-ST） and one-leg speedy jump test （OL-SJ））. The LSI was calculated by dividing the dominant leg by the nondominant leg and multiplying by 100. Kruskal-Wallis H tests and binary logistic regression analyses were conducted. Results： There were significant differences between the LSI of the 3 age-related performance-level groups only in the strength-related tests： the OL-CMJ （X^2（2, 285） = 9.09; p = 0.01） and the OL-ILS （X^2（2,285） = 14.79; p 〈 0.01）. The LSI for OL-ILS was found to be a significant risk factor for traumatic injury in youth ski racers （Wald = 7.08; p 〈 0.01）. No significant risk factors were found for overuse injuries. Conclusion： Younger athletes display slightly greater LSI values only in the strength-related tests. The cut-off value of limb differences of 〈 10% for return to sport decisions seems to be appropriate for elite athletes, but for youth and adolescent athletes it has to be critically discussed. It seems to be necessary to define thresholds based on specific performance tasks （strength vs. coordination related） rather than on generalizations, and age-related performance levels must be considered. Limb differences in unilateral leg extension strength represent a significant injury risk factor in youth ski racers.2018 Published by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license. （http：//creativecommons.org/licenses/by-nc-nd/4.0/）.展开更多
This paper tries to demonstrate that the principle of the risk allocation based on the balance is the most effective way to resolve the risk allocation problems of public-private partnership （PPP） contracts and pres...This paper tries to demonstrate that the principle of the risk allocation based on the balance is the most effective way to resolve the risk allocation problems of public-private partnership （PPP） contracts and presents suggestions how to carry out this principle. For PPP projects, it is necessary to set up a workable and commercially viable risk sharing mechanism to satisfy the different interests and the objectives of both the public sector and the private sector. An effective risk allocation mechanism is not only an important part in preparing project documents, but also an essential part in the success of PPP contracts. Risk allocation can be represented in a risk matrix. The more balanced the risk allocation is, the lower the risk degree of PPP contracts is. Therefore, the most effective risk allocation of PPP contracts is that the public sector and the private sector take part in risk management together in all the stages of the project and allocate the balanced risks. The outcomes of this paper can be used by both the public sector and the private sector to make a good choice of the PPP contract form.展开更多
The aim of the research was to evaluate overall quality of introduction of hazard analysis and critical control points （HACCP） prerequisites and HACCP procedures in catering sector in Latvia to reveal common problem...The aim of the research was to evaluate overall quality of introduction of hazard analysis and critical control points （HACCP） prerequisites and HACCP procedures in catering sector in Latvia to reveal common problems that can provoke food-borne infection outbreaks. Certain quantitative indicators were defined and analyzed to conclude about characteristic trends related to implementation of food safety legislation. The state＇s monitoring data on surveillance of catering establishments were used. Fulfillment of legislative requirements in about 6,000 catering establishments was evaluated during time period of 2004-2009. The results of investigation were obtained with help of statistical analyses using MS Excel computer program. The results of the research suggest that most of catering establishments （e.g., 83.6% during 2009） meet the hygiene requirements only partly. Non-conformities regarding HACCP-based self-control procedures were fixed during 49.2% of inspections. The research reveals characteristic shortcomings that are established from year to year, e.g., improper hygiene of premises （established during 30%-40% of inspections, depending on the year）, poor hygiene of technological equipment （established during 27%-37% of inspections）, poor personnel hygiene （established during 11%-22% of inspections）, inadequate competence of food service personnel （established during 10%-35% of inspections）, as well as non-observance of cleaning-disinfection procedures and technological parameters for food processing （established during 11%-25% of inspections, depending on the year）. Actual shortcomings can lead to both the direct and the indirect cross-contamination of food. On the base of the research, it was concluded that further detailed assessment of potential food safety risks is relevant to establish risk-based monitoring activities in catering sector.展开更多
On the basis of the reaction rules and its influencing factors of sulfur compounds in MIP naphtha, a correlation model for describing the correlation between mass fraction of sulfur in MIP naphtha, mass fraction of su...On the basis of the reaction rules and its influencing factors of sulfur compounds in MIP naphtha, a correlation model for describing the correlation between mass fraction of sulfur in MIP naphtha, mass fraction of sulfur in feedstock and volume fraction of olefin in naphtha was developed and the model＇s parameters were estimated. The residual error distribution and statistical study showed that the developed model was reasonable and reliable and able to predict the mass fraction of sulfur compounds in naphtha. The correlation model can provide theoretical guidance and operation base for adjusting process parameters to produce EURO IV gasoline by the MIP units. The model was validated by its application on the MIP unit of Qingdao Refining ＆ Chemical Company. On this unit, the tail oil with low sulfur content obtained via hydrotreating gas oil was used as the feedstock and the olefin content of naphtha was reduced by promoting hydrogen transfer reaction through adjustment of process parameters. Thus, EURO IV clean gasoline was manufactured by this MIP unit.展开更多
The financial crisis in late 2008 arrested economic development in the construction sector in the Middle East, with the result that investors＇ confidence in the sector is severely depressed. Delays constitute one of ...The financial crisis in late 2008 arrested economic development in the construction sector in the Middle East, with the result that investors＇ confidence in the sector is severely depressed. Delays constitute one of the highest impediments to project success. In this respect, the traditional management is no longer sufficient for construction project success. The objective of this study is to conduct a literature review to identify additional effective measures for controlling the potential delays risks in construction projects in order to maximize the opportunities for success in those projects. Thirty-six scholarly articles published between 2000 and 2011 are reviewed to identify related MDRC （measures for delays risks control）. This survey reveals that 60% of the studies are related to decision-making, performance, risk management variations and poor management knowledge of stakeholders and that 20% of these studies are undertaken in the Middle East. A further 25% of the studies are related to the lack of financial risk by stakeholders, and of these 14% are in the Middle East. A knowledge gap is identified in terms of project performance, stakeholder management and risk management, which are seen as significant measures of success in controlling project delay.展开更多
Floor water inrush is one of the main types of coal mine water hazards.With the development of deep mining,the prediction and evaluation of floor water inrush is particularly significant.This paper proposes a variable...Floor water inrush is one of the main types of coal mine water hazards.With the development of deep mining,the prediction and evaluation of floor water inrush is particularly significant.This paper proposes a variable weight model,which combines a multi-factor interaction matrix(MFIM)and the technique for order performance by similarity to ideal solution(TOPSIS)to implement the risk assessment of floor water inrush in coal mines.Based on the MFIM,the interaction between seven evaluation indices,including the confined water pressure,water supply condition and aquifer water yield property,floor aquifuge thickness,fault water transmitting ability,fracture development degree,mining depth and thickness and their influence on floor water inrush were considered.After calculating the constant weights,the active degree evaluation was used to assign a variable weight to the indices.The values of the middle layer and final risk level were obtained by TOPSIS.The presented model was successfully applied in the 9901 working face in the Taoyang Mine and four additional coal mines and the results were highly consistent with the engineering situations.Compared with the existing nonlinear evaluation methods,the proposed model had advantages in terms of the weighting,principle explanation,and algorithm structure.展开更多
A new method for submarine pipeline routing risk quantitative analysis was provided, and the study was developed from qualitative analysis to quantitative analysis.The characteristics of the potential risk of the subm...A new method for submarine pipeline routing risk quantitative analysis was provided, and the study was developed from qualitative analysis to quantitative analysis.The characteristics of the potential risk of the submarine pipeline system were considered, and grey-mode identification theory was used. The study process was composed of three parts: establishing the indexes system of routing risk quantitative analysis, establishing the model of grey-mode identification for routing risk quantitative analysis, and establishing the standard of mode identification result. It is shown that this model can directly and concisely reflect the hazard degree of the routing through computing example, and prepares the routing selection for the future.展开更多
AIM:To conduct a meta-analysis to estimate the determinants of the association between erosive esophagitis (EE)and body mass index(BMI). METHODS:We identified the studies using PubMed. Studies were selected for analys...AIM:To conduct a meta-analysis to estimate the determinants of the association between erosive esophagitis (EE)and body mass index(BMI). METHODS:We identified the studies using PubMed. Studies were selected for analysis based on certain inclusion and exclusion criteria.Data were extracted from each study on the basis of predefined items.Metaanalyses were performed to verify the risk factors,such as obesity and gender. RESULTS:Twenty-one studies were included in this systematic review.These studies demonstrated an association between increasing BMI and the presence of EE[95%confidence interval(CI):1.35-1.88,overweight,odds ratio(OR)=1.60,P value homogeneity =0.003,95%CI:1.65-2.55,obese,OR=2.05,P< 0.01].The heterogeneity disappeared by stratifying for gender.No publication bias was observed in this metaanalysis by the Egger method. CONCLUSION:This analysis demonstrates a positive association between BMI and the presence of EE,especially in males.The risk seems to progressively increase with increasing weight.展开更多
文摘A model of continuous-time insider trading in which a risk-neutral in-sider possesses two imperfect correlated signals of a risky asset is studied.By conditional expectation theory and filtering theory,we first establish three lemmas:normal corre-lation,equivalent pricing and equivalent profit,which can guarantee to turn our model into a model with insider knowing full information.Then we investigate the impact of the two correlated signals on the market equilibrium consisting of optimal insider trading strategy and semi-strong pricing rule.It shows that in the equilibrium,(1)the market depth is constant over time;(2)if the two noisy signals are not linerly correlated,then all private information of the insider is incorporated into prices in the end while the whole information on the asset value can not incorporated into prices in the end;(3)if the two noisy signals are linear correlated such that the insider can infer the whole information of the asset value,then our model turns into a model with insider knowing full information;(4)if the two noisy signals are the same then the total ex ant profit of the insider is increasing with the noise decreasing,while down to O as the noise going up to infinity;(5)if the two noisy signals are not linear correlated then with one noisy signal fixed,the total ex ante profit of the insider is single-peaked with a unique minimum with respect to the other noisy signal value,and furthermore as the noisy value going to O it gets its maximum,the profit in the case that the real value is observed.
基金Supported by Special Research Fund for Public Sector(Agriculture)(200903055)~~
文摘[Objective] The study was to explore the major factors affecting diary cattle brucellosis risk assessment,as well as their strong-to-weak sequence,so as to provide theoretical basis for assessing diary cattle brucellosis risk level in different regions.[Method] From 4 dimensions of feeding and importing,breeding,housing and polyculture situation,an evaluation index system was set up,and diary cattle brucellosis risk survey was conducted in 3 typical regions.Finally,systematic multilevel grey relation entropy method was applied to perform data analysis.[Result] The strong-to-weak sequence of Level 1 impact factor of diary cattle brucellosis was as follows：feeding and importinghousingpolyculture situationbreeding;the sequence of Level 2 impact factor was U32〉U12〉U11〉U31〉U21〉U42〉U43〉U23〉U22〉U41;the risk level sequence of 3 typical regions was Province A（County A1,A2,A3）Province B（County B1,B2,B3）Province C（County C1,C2,C3）.[Conclusion] According to the weight of Level 1 index strata,administrative departments at all levels and dairy cattle farmers should lay emphasis on the aspects of feeding,importing and housing;viewed from the perspective of Level 2 index strata,dairy cattle farmers should value the siting of cattle field,the brucellosis surveillance before importing and milking modes most.According to the diary cattle brucellosis risk level of 3 typical regions,if administrative departments at all levels strengthen peoples＇ awareness of their personal health and increase investment in this area,with new healthy cultured atmosphere built,the risk level of diary cattle brucellosis will surly decline.
文摘Objective Several studies have examined the relationships between dietary potassium and sodium and hypertension, but few have evaluated the association between serum potassium or sodium and risk of incident hypertension. We therefore investigated the associations between serum potassium and sodium and risk of incident hypertension in a Chinese community-based population. Methods A total of 839 normotensive individuals without cardiovascular disease from the Chinese Multi-Provincial Cohort Study who took part in the baseline examination in 2007-2008 and the follow-up survey in 2012-2013 were included in this study. Odds ratios （OR） and 95% confidence intervals （95%CI） for baseline serum potassium and sodium in relation to the risk of new-onset hypertension were evaluated using multivari- ate logistic regression models. Results During five years of follow-up, 218 （26.0%） individuals progressed to hypertension. Logistic re- gression adjusting for multiple confounders showed that every 1 mEq/L increment in baseline serum potassium level was associated with a 75% increased risk of hypertension （OR： 1.75; 95%CI： 1.01-3.04; P = 0.04）. Compared with adults with serum potassium level of 4.20-4.79 mEq/L, adults with level 〉 4.80 mEq/L had an 84% increased risk of hypertension （OR： 1.84; 95%CI： 1.14-2.96; P = 0.01）. There was no significant association between serum sodium and risk of hypertension （OR： 0.96; 95%CI： 0.89-1.04; P = 0.33）. Conclusions Base- line serum potassium level, but not baseline serum sodium level, was positively related to the risk of incident hypertension in the Chinese population.
文摘Purpose： The aims of this study were to assess differences of limb symmetry index （LSI） in strength- and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related performance levels and to prospectively assess limb differences as a possible risk factor for traumatic and overuse injury in youth ski racers. Methods： The study （Study 1） included 285 high-level competitive ski racers （125 females, 160 males） of 3 age-related performance levels and based on the school system： 95 youth （10-14 years, secondary modem school）, 107 adolescent （15-19 years, grammar school）, and 83 elite athletes （20-34 years）. To investigate the second aim （Study 2）, 67 of the 95 youth athletes were included and any traumatic or overuse injuries were prospectively recorded over 2 seasons. All athletes performed 4 unilateral tests （strength related： one-leg counter movement jump （OL-CMJ） and one-leg isometric/isokinetic press strength test （OL-ILS）; coordination related： one-leg stability test （OL-ST） and one-leg speedy jump test （OL-SJ））. The LSI was calculated by dividing the dominant leg by the nondominant leg and multiplying by 100. Kruskal-Wallis H tests and binary logistic regression analyses were conducted. Results： There were significant differences between the LSI of the 3 age-related performance-level groups only in the strength-related tests： the OL-CMJ （X^2（2, 285） = 9.09; p = 0.01） and the OL-ILS （X^2（2,285） = 14.79; p 〈 0.01）. The LSI for OL-ILS was found to be a significant risk factor for traumatic injury in youth ski racers （Wald = 7.08; p 〈 0.01）. No significant risk factors were found for overuse injuries. Conclusion： Younger athletes display slightly greater LSI values only in the strength-related tests. The cut-off value of limb differences of 〈 10% for return to sport decisions seems to be appropriate for elite athletes, but for youth and adolescent athletes it has to be critically discussed. It seems to be necessary to define thresholds based on specific performance tasks （strength vs. coordination related） rather than on generalizations, and age-related performance levels must be considered. Limb differences in unilateral leg extension strength represent a significant injury risk factor in youth ski racers.2018 Published by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license. （http：//creativecommons.org/licenses/by-nc-nd/4.0/）.
文摘This paper tries to demonstrate that the principle of the risk allocation based on the balance is the most effective way to resolve the risk allocation problems of public-private partnership （PPP） contracts and presents suggestions how to carry out this principle. For PPP projects, it is necessary to set up a workable and commercially viable risk sharing mechanism to satisfy the different interests and the objectives of both the public sector and the private sector. An effective risk allocation mechanism is not only an important part in preparing project documents, but also an essential part in the success of PPP contracts. Risk allocation can be represented in a risk matrix. The more balanced the risk allocation is, the lower the risk degree of PPP contracts is. Therefore, the most effective risk allocation of PPP contracts is that the public sector and the private sector take part in risk management together in all the stages of the project and allocate the balanced risks. The outcomes of this paper can be used by both the public sector and the private sector to make a good choice of the PPP contract form.
文摘The aim of the research was to evaluate overall quality of introduction of hazard analysis and critical control points （HACCP） prerequisites and HACCP procedures in catering sector in Latvia to reveal common problems that can provoke food-borne infection outbreaks. Certain quantitative indicators were defined and analyzed to conclude about characteristic trends related to implementation of food safety legislation. The state＇s monitoring data on surveillance of catering establishments were used. Fulfillment of legislative requirements in about 6,000 catering establishments was evaluated during time period of 2004-2009. The results of investigation were obtained with help of statistical analyses using MS Excel computer program. The results of the research suggest that most of catering establishments （e.g., 83.6% during 2009） meet the hygiene requirements only partly. Non-conformities regarding HACCP-based self-control procedures were fixed during 49.2% of inspections. The research reveals characteristic shortcomings that are established from year to year, e.g., improper hygiene of premises （established during 30%-40% of inspections, depending on the year）, poor hygiene of technological equipment （established during 27%-37% of inspections）, poor personnel hygiene （established during 11%-22% of inspections）, inadequate competence of food service personnel （established during 10%-35% of inspections）, as well as non-observance of cleaning-disinfection procedures and technological parameters for food processing （established during 11%-25% of inspections, depending on the year）. Actual shortcomings can lead to both the direct and the indirect cross-contamination of food. On the base of the research, it was concluded that further detailed assessment of potential food safety risks is relevant to establish risk-based monitoring activities in catering sector.
文摘On the basis of the reaction rules and its influencing factors of sulfur compounds in MIP naphtha, a correlation model for describing the correlation between mass fraction of sulfur in MIP naphtha, mass fraction of sulfur in feedstock and volume fraction of olefin in naphtha was developed and the model＇s parameters were estimated. The residual error distribution and statistical study showed that the developed model was reasonable and reliable and able to predict the mass fraction of sulfur compounds in naphtha. The correlation model can provide theoretical guidance and operation base for adjusting process parameters to produce EURO IV gasoline by the MIP units. The model was validated by its application on the MIP unit of Qingdao Refining ＆ Chemical Company. On this unit, the tail oil with low sulfur content obtained via hydrotreating gas oil was used as the feedstock and the olefin content of naphtha was reduced by promoting hydrogen transfer reaction through adjustment of process parameters. Thus, EURO IV clean gasoline was manufactured by this MIP unit.
文摘The financial crisis in late 2008 arrested economic development in the construction sector in the Middle East, with the result that investors＇ confidence in the sector is severely depressed. Delays constitute one of the highest impediments to project success. In this respect, the traditional management is no longer sufficient for construction project success. The objective of this study is to conduct a literature review to identify additional effective measures for controlling the potential delays risks in construction projects in order to maximize the opportunities for success in those projects. Thirty-six scholarly articles published between 2000 and 2011 are reviewed to identify related MDRC （measures for delays risks control）. This survey reveals that 60% of the studies are related to decision-making, performance, risk management variations and poor management knowledge of stakeholders and that 20% of these studies are undertaken in the Middle East. A further 25% of the studies are related to the lack of financial risk by stakeholders, and of these 14% are in the Middle East. A knowledge gap is identified in terms of project performance, stakeholder management and risk management, which are seen as significant measures of success in controlling project delay.
基金Projects(41877239,51379112,51422904,40902084,41772298)supported by the National Natural Science Foundation of ChinaProject(2019GSF111028)supported by the Key Technology Research and Development Program of Shandong Province,China+1 种基金Project(2018JC044)supported by the Fundamental Research Funds of Shandong University,ChinaProject(JQ201513)supported by the Natural Science Foundation of Shandong Province,China。
文摘Floor water inrush is one of the main types of coal mine water hazards.With the development of deep mining,the prediction and evaluation of floor water inrush is particularly significant.This paper proposes a variable weight model,which combines a multi-factor interaction matrix(MFIM)and the technique for order performance by similarity to ideal solution(TOPSIS)to implement the risk assessment of floor water inrush in coal mines.Based on the MFIM,the interaction between seven evaluation indices,including the confined water pressure,water supply condition and aquifer water yield property,floor aquifuge thickness,fault water transmitting ability,fracture development degree,mining depth and thickness and their influence on floor water inrush were considered.After calculating the constant weights,the active degree evaluation was used to assign a variable weight to the indices.The values of the middle layer and final risk level were obtained by TOPSIS.The presented model was successfully applied in the 9901 working face in the Taoyang Mine and four additional coal mines and the results were highly consistent with the engineering situations.Compared with the existing nonlinear evaluation methods,the proposed model had advantages in terms of the weighting,principle explanation,and algorithm structure.
文摘A new method for submarine pipeline routing risk quantitative analysis was provided, and the study was developed from qualitative analysis to quantitative analysis.The characteristics of the potential risk of the submarine pipeline system were considered, and grey-mode identification theory was used. The study process was composed of three parts: establishing the indexes system of routing risk quantitative analysis, establishing the model of grey-mode identification for routing risk quantitative analysis, and establishing the standard of mode identification result. It is shown that this model can directly and concisely reflect the hazard degree of the routing through computing example, and prepares the routing selection for the future.
文摘AIM:To conduct a meta-analysis to estimate the determinants of the association between erosive esophagitis (EE)and body mass index(BMI). METHODS:We identified the studies using PubMed. Studies were selected for analysis based on certain inclusion and exclusion criteria.Data were extracted from each study on the basis of predefined items.Metaanalyses were performed to verify the risk factors,such as obesity and gender. RESULTS:Twenty-one studies were included in this systematic review.These studies demonstrated an association between increasing BMI and the presence of EE[95%confidence interval(CI):1.35-1.88,overweight,odds ratio(OR)=1.60,P value homogeneity =0.003,95%CI:1.65-2.55,obese,OR=2.05,P< 0.01].The heterogeneity disappeared by stratifying for gender.No publication bias was observed in this metaanalysis by the Egger method. CONCLUSION:This analysis demonstrates a positive association between BMI and the presence of EE,especially in males.The risk seems to progressively increase with increasing weight.
