Trend forecasting is an important aspect in fault diagnosis and work state supervision. The principle, where Grey theory is applied in fault forecasting, is that the forecast system is considered as a Grey system; the...Trend forecasting is an important aspect in fault diagnosis and work state supervision. The principle, where Grey theory is applied in fault forecasting, is that the forecast system is considered as a Grey system; the existing known information is used to infer the unknown information's character, state and development trend in a fault pattern, and to make possible forecasting and decisions for future development. It involves the whitenization of a Grey process. But the traditional equal time interval Grey GM (1,1) model requires equal interval data and needs to bring about accumulating addition generation and reversion calculations. Its calculation is very complex. However, the non equal interval Grey GM (1,1) model decreases the condition of the primitive data when establishing a model, but its requirement is still higher and the data were pre processed. The abrasion primitive data of plant could not always satisfy these modeling requirements. Therefore, it establishes a division method suited for general data modeling and estimating parameters of GM (1,1), the standard error coefficient that was applied to judge accuracy height of the model was put forward; further, the function transform to forecast plant abrasion trend and assess GM (1,1) parameter was established. These two models need not pre process the primitive data. It is not only suited for equal interval data modeling, but also for non equal interval data modeling. Its calculation is simple and convenient to use. The oil spectrum analysis acted as an example. The two GM (1,1) models put forward in this paper and the new information model and its comprehensive usage were investigated. The example shows that the two models are simple and practical, and worth expanding and applying in plant fault diagnosis.展开更多
Gemstones have fascinated mankind forever,and people traveled far to find them.The Silk Road is one of the most traditional trade routes in the middle ages that was used to bring the precious stones to the European ma...Gemstones have fascinated mankind forever,and people traveled far to find them.The Silk Road is one of the most traditional trade routes in the middle ages that was used to bring the precious stones to the European market.Later,emeralds from Colombia were shipped via the ocean to the Old World.展开更多
Background: Family planning has clearly been a major public health success as evidenced by substantial fertility decline and reductions in maternal mortality in countries with high contraceptive prevalence rates. Nige...Background: Family planning has clearly been a major public health success as evidenced by substantial fertility decline and reductions in maternal mortality in countries with high contraceptive prevalence rates. Nigerian governments have continued to expand the scope and improve accessibility and availability of contraceptive commodities to improve uptake, giving the numerous benefits. Objective: To determine the trends in contraceptive usage and the preferred method among clients visiting the family planning clinic of University of Port Harcourt Teaching Hospital (UPTH), Nigeria. Method: It was a cross sectional study of all clients who accepted contraceptive methods at the UPTH, between 1st January 2000 and 31st December, 2015. Results: During the period, a total of 9190 clients accepted contraceptive methods, and 40,334 women were delivered in the maternity unit giving an acceptance rate of 1 in 4 deliveries or 22.8%. The acceptors of modern contraceptives increased steadily from 491 clients in 2001 to a peak in 2008 with 1477 clients and sharply declined to 381 in 2009 before increasing gradually again to 519 clients in 2015. The most commonly used method was the male condom by 3194 clients (37.9%), followed by injectables, which was accepted by 2185 clients (23.8%) while 1752 clients (19.1%) used the IUD. Implant contraceptive was used by 915 clients (9.9%), followed by oral contraceptive pills used by 547 (6.0%). Female sterilization was the least commonly used method by 302 clients (3.3%). There was no vasectomy over the 15 years period. Conclusion: Contraceptive trend in Port Harcourt has an ambivalent acceptance pattern. Although male condom and injectable contraceptives are the most commonly used method over time, the subdermal implants are increasingly becoming very popular in recent time. Female sterilization remains the least common method with no record of vasectomy.展开更多
The impact trend of rock-coal system was studied by the method of accumulat- ing and releasing of deformation energy and interaction of rock-coal system.The system model of roof-coal-floor was established.Based on the...The impact trend of rock-coal system was studied by the method of accumulat- ing and releasing of deformation energy and interaction of rock-coal system.The system model of roof-coal-floor was established.Based on the RFPA software,rock fracture process analysis system,the numerical test of deformation,fracture and energy transmis- sion of nonlinear and nonhomogeneous rock-coal system,and the numerical test and evaluating method of impact trend of rock-coal system were achieved.When the same coal seam was in different roof and floor conditions,the fracture process of rock-coal sys- tem can be classified as gradual,sudden and delayed fracture three kinds,and their im- pact trend can be classified as void,intense and medium correspondingly.The rock-coal system's impact trend is evaluated by the system impact index μ and burst expanding forms.The criteria μ are μ<1.0,1.0≤μ<1.5 and μ≥1.5 when the impact trend is void,in- tense or medium,which are tested and verified by the No.2 and No.4 coal seams in Sun- cun mine.展开更多
由于数据定价对促进企业数字化转型、构建数据要素市场和促进经济可持续发展具有重要意义,因此借助CiteSpace文献计量分析软件,以中国知网、Web of Science数据库中相关研究文献为数据源,聚焦数据定价研究的主题演变、趋势、时代背景,对...由于数据定价对促进企业数字化转型、构建数据要素市场和促进经济可持续发展具有重要意义,因此借助CiteSpace文献计量分析软件,以中国知网、Web of Science数据库中相关研究文献为数据源,聚焦数据定价研究的主题演变、趋势、时代背景,对1993—2022年国内外数据定价权威文献进行计量分析。研究发现,1993—2022年国内外数据定价的研究整体呈波动上升趋势,近3年热度明显;研究模式国外多为合作共享研究而国内多为独立研究,均缺乏研究机构与数据供应商的合作研究;研究内容国内侧重于数据定价的成本效益、公平交易、隐私权属等,国外则侧重于数据定价的隐私安全与保护、人工智能算法、客户服务质量等,均与信息技术的发展密切相关;未来,数据定价研究将进一步立足“双碳”背景,结合环境、社会和公司治理(Environmental,Social and Governance,ESG)投资理念,布局和拓展新视角。展开更多
文摘Trend forecasting is an important aspect in fault diagnosis and work state supervision. The principle, where Grey theory is applied in fault forecasting, is that the forecast system is considered as a Grey system; the existing known information is used to infer the unknown information's character, state and development trend in a fault pattern, and to make possible forecasting and decisions for future development. It involves the whitenization of a Grey process. But the traditional equal time interval Grey GM (1,1) model requires equal interval data and needs to bring about accumulating addition generation and reversion calculations. Its calculation is very complex. However, the non equal interval Grey GM (1,1) model decreases the condition of the primitive data when establishing a model, but its requirement is still higher and the data were pre processed. The abrasion primitive data of plant could not always satisfy these modeling requirements. Therefore, it establishes a division method suited for general data modeling and estimating parameters of GM (1,1), the standard error coefficient that was applied to judge accuracy height of the model was put forward; further, the function transform to forecast plant abrasion trend and assess GM (1,1) parameter was established. These two models need not pre process the primitive data. It is not only suited for equal interval data modeling, but also for non equal interval data modeling. Its calculation is simple and convenient to use. The oil spectrum analysis acted as an example. The two GM (1,1) models put forward in this paper and the new information model and its comprehensive usage were investigated. The example shows that the two models are simple and practical, and worth expanding and applying in plant fault diagnosis.
文摘Gemstones have fascinated mankind forever,and people traveled far to find them.The Silk Road is one of the most traditional trade routes in the middle ages that was used to bring the precious stones to the European market.Later,emeralds from Colombia were shipped via the ocean to the Old World.
文摘Background: Family planning has clearly been a major public health success as evidenced by substantial fertility decline and reductions in maternal mortality in countries with high contraceptive prevalence rates. Nigerian governments have continued to expand the scope and improve accessibility and availability of contraceptive commodities to improve uptake, giving the numerous benefits. Objective: To determine the trends in contraceptive usage and the preferred method among clients visiting the family planning clinic of University of Port Harcourt Teaching Hospital (UPTH), Nigeria. Method: It was a cross sectional study of all clients who accepted contraceptive methods at the UPTH, between 1st January 2000 and 31st December, 2015. Results: During the period, a total of 9190 clients accepted contraceptive methods, and 40,334 women were delivered in the maternity unit giving an acceptance rate of 1 in 4 deliveries or 22.8%. The acceptors of modern contraceptives increased steadily from 491 clients in 2001 to a peak in 2008 with 1477 clients and sharply declined to 381 in 2009 before increasing gradually again to 519 clients in 2015. The most commonly used method was the male condom by 3194 clients (37.9%), followed by injectables, which was accepted by 2185 clients (23.8%) while 1752 clients (19.1%) used the IUD. Implant contraceptive was used by 915 clients (9.9%), followed by oral contraceptive pills used by 547 (6.0%). Female sterilization was the least commonly used method by 302 clients (3.3%). There was no vasectomy over the 15 years period. Conclusion: Contraceptive trend in Port Harcourt has an ambivalent acceptance pattern. Although male condom and injectable contraceptives are the most commonly used method over time, the subdermal implants are increasingly becoming very popular in recent time. Female sterilization remains the least common method with no record of vasectomy.
基金the Ministry of Education Backbone Teachers Funded Projects
文摘The impact trend of rock-coal system was studied by the method of accumulat- ing and releasing of deformation energy and interaction of rock-coal system.The system model of roof-coal-floor was established.Based on the RFPA software,rock fracture process analysis system,the numerical test of deformation,fracture and energy transmis- sion of nonlinear and nonhomogeneous rock-coal system,and the numerical test and evaluating method of impact trend of rock-coal system were achieved.When the same coal seam was in different roof and floor conditions,the fracture process of rock-coal sys- tem can be classified as gradual,sudden and delayed fracture three kinds,and their im- pact trend can be classified as void,intense and medium correspondingly.The rock-coal system's impact trend is evaluated by the system impact index μ and burst expanding forms.The criteria μ are μ<1.0,1.0≤μ<1.5 and μ≥1.5 when the impact trend is void,in- tense or medium,which are tested and verified by the No.2 and No.4 coal seams in Sun- cun mine.
文摘由于数据定价对促进企业数字化转型、构建数据要素市场和促进经济可持续发展具有重要意义,因此借助CiteSpace文献计量分析软件,以中国知网、Web of Science数据库中相关研究文献为数据源,聚焦数据定价研究的主题演变、趋势、时代背景,对1993—2022年国内外数据定价权威文献进行计量分析。研究发现,1993—2022年国内外数据定价的研究整体呈波动上升趋势,近3年热度明显;研究模式国外多为合作共享研究而国内多为独立研究,均缺乏研究机构与数据供应商的合作研究;研究内容国内侧重于数据定价的成本效益、公平交易、隐私权属等,国外则侧重于数据定价的隐私安全与保护、人工智能算法、客户服务质量等,均与信息技术的发展密切相关;未来,数据定价研究将进一步立足“双碳”背景,结合环境、社会和公司治理(Environmental,Social and Governance,ESG)投资理念,布局和拓展新视角。
