Analysis of catchment Land use/Land cover (LULC) change is a vital tool in ensuring sustainable catchment management. The study analyzed land use/land cover changes in the Rwizi catchment, south western Uganda from 19...Analysis of catchment Land use/Land cover (LULC) change is a vital tool in ensuring sustainable catchment management. The study analyzed land use/land cover changes in the Rwizi catchment, south western Uganda from 1989-2019 and projected the trend by 2040. Landsat images, field observations, key informant interviews and focus group discussions were used to collect data. Changes in cropland, forestland, built up area, grazing land, wetland and open water bodies were analyzed in ArcGIS version 10.2.2 and ERDAS IMAGINE 14 software and a Markov chain model. All the LULC classes increased in area except grazing land. Forest land and builtup area between 2009-2019 increased by 370.03% and 229.53% respectively. Projections revealed an increase in forest land and builtup area by 2030 and only built up area by 2040. LULCC in the catchment results from population pressure, reduced soil fertility and high value of agricultural products.展开更多
This study examines vishing, a form of social engineering scam using voice communication to deceive individuals into revealing sensitive information or losing money. With the rise of smartphone usage, people are more ...This study examines vishing, a form of social engineering scam using voice communication to deceive individuals into revealing sensitive information or losing money. With the rise of smartphone usage, people are more susceptible to vishing attacks. The proposed Emoti-Shing model analyzes potential victims’ emotions using Hidden Markov Models to track vishing scams by examining the emotional content of phone call audio conversations. This approach aims to detect vishing scams using biological features of humans, specifically emotions, which cannot be easily masked or spoofed. Experimental results on 30 generated emotions indicate the potential for increased vishing scam detection through this approach.展开更多
It is important to consider the changing states in hedging.The Markov regime-switching dynamic correlation multivariate stochastic volatility( MRS-DC-MSV) model was proposed to solve this issue. DC-MSV model and MRS-D...It is important to consider the changing states in hedging.The Markov regime-switching dynamic correlation multivariate stochastic volatility( MRS-DC-MSV) model was proposed to solve this issue. DC-MSV model and MRS-DC-MSV model were used to calculate the time-varying hedging ratios and compare the hedging performance. The Markov chain Monte Carlo( MCMC) method was used to estimate the parameters. The results showed that,there were obviously two economic states in Chinese financial market. Two models all did well in hedging,but the performance of MRS-DCMSV model was better. It could reduce risk by nearly 90%. Thus,in the hedging period,changing states is a factor that cannot be neglected.展开更多
Retailing is a dynamic business domain where commodities and goods are sold in small quantities directly to the customers.It deals with the end user customers of a supply-chain network and therefore has to accommodate...Retailing is a dynamic business domain where commodities and goods are sold in small quantities directly to the customers.It deals with the end user customers of a supply-chain network and therefore has to accommodate the needs and desires of a large group of customers over varied utilities.The volume and volatility of the business makes it one of the prospectivefields for analytical study and data modeling.This is also why customer segmentation drives a key role in multiple retail business decisions such as marketing budgeting,customer targeting,customized offers,value proposition etc.The segmentation could be on various aspects such as demographics,historic behavior or preferences based on the use cases.In this paper,historic retail transactional data is used to segment the custo-mers using K-Means clustering and the results are utilized to arrive at a transition matrix which is used to predict the cluster movements over the time period using Markov Model algorithm.This helps in calculating the futuristic value a segment or a customer brings to the business.Strategic marketing designs and budgeting can be implemented using these results.The study is specifically useful for large scale marketing in domains such as e-commerce,insurance or retailers to segment,profile and measure the customer lifecycle value over a short period of time.展开更多
Modeling urban land-use dynamics is critical for urban experts’and infrastructure managers’planning.This study attempts to explore the land-use/land-cover(LULC)dynamics of Gondar using satellite images from 1984 to ...Modeling urban land-use dynamics is critical for urban experts’and infrastructure managers’planning.This study attempts to explore the land-use/land-cover(LULC)dynamics of Gondar using satellite images from 1984 to 2020.Markov-Chain and Cellular Automata(MC-CA)models have been recognized as performing well in predicting urban land-use change.However,only a few models work in Ethiopia in general,and no study in Gondar has applied this approach to study urban land-use patterns.Therefore,Gondar land-use/land cover changes of Gondar were predicted using the MC-CA model in IDRISI.The built-up area in Gondar city covered 1413 ha(3%of the total area)in 1984 and increased to 2380 ha(5%)in 1994;21153 ha(45.5%)in 2004;22622 ha(48.7%)in 2014;and 23427 ha(50.5%)in 2020.The area has been predicted to reach 57.5%in the 2050s,showing a faster increase that will cause a very vast loss of farmland.This will increase urban sprawl challenges as well as overall environmental disequilibrium in the preceding decade.Thus,innovative and careful structures and systems in urban planning are required to secure a sustainable urban future and to make our cities livable and competitive in the paradigm of sustainable cities.展开更多
In this paper,the distributed stochastic model predictive control(MPC)is proposed for the noncooperative game problem of the discrete-time multi-player systems(MPSs)with the undirected Markov jump graph.To reflect the...In this paper,the distributed stochastic model predictive control(MPC)is proposed for the noncooperative game problem of the discrete-time multi-player systems(MPSs)with the undirected Markov jump graph.To reflect the reality,the state and input constraints have been considered along with the external disturbances.An iterative algorithm is designed such that model predictive noncooperative game could converge to the socalledε-Nash equilibrium in a distributed manner.Sufficient conditions are established to guarantee the convergence of the proposed algorithm.In addition,a set of easy-to-check conditions are provided to ensure the mean-square uniform bounded stability of the underlying MPSs.Finally,a numerical example on a group of spacecrafts is studied to verify the effectiveness of the proposed method.展开更多
目的基于Markov模型评价肺结节低剂量螺旋CT(LDCT)筛查的卫生经济学。方法利用2021年—2023年北京市某三甲医院的肺结节LDCT筛查数据和部分国外临床研究数据,采用成本效用分析方法,通过增量成本效用比(ICUR)确定优势筛查策略;使用R语言...目的基于Markov模型评价肺结节低剂量螺旋CT(LDCT)筛查的卫生经济学。方法利用2021年—2023年北京市某三甲医院的肺结节LDCT筛查数据和部分国外临床研究数据,采用成本效用分析方法,通过增量成本效用比(ICUR)确定优势筛查策略;使用R语言获得转移概率参数,利用TreeAge Pro 2011软件构建Markov模型。假设以我国10万名55岁及以上人群为肺结节筛查对象,模拟其疾病发展情况,并通过敏感性分析评价该模型的稳定性。结果成本效用分析显示,该模型经20次循环后,LDCT筛查策略的总成本为3543088618元,相较于不筛查策略的总成本增加了784130651元,额外获得了7996个质量调整生命年(QALY),每获得一个QALY需多花费98059.77元。采用WHO卫生经济学评价标准,LDCT筛查策略的ICUR大于1倍人均国内生产总值(GDP)但小于3倍人均GDP,为优势策略。敏感性分析显示,各变量在其敏感性分析范围内无论如何变化,都不会对ICUR产生较大影响,表明该模型具有较好的稳定性。结论在55岁及以上人群中开展每年一次肺结节LDCT筛查的ICUR小于3倍人均GDP,具有一定的经济学效用,该筛查策略有利于肺癌的“早发现、早诊断、早治疗”。展开更多
目的:基于中国卫生服务体系角度评价血塞通软胶囊对比安慰剂治疗缺血性中风患者的经济性。方法:基于血塞通软胶囊的Ⅲ期对照试验和已发表的文献数据构建markov模型,模拟患者终身的质量调整生命年(quality-adjusted life year,QALY)和增...目的:基于中国卫生服务体系角度评价血塞通软胶囊对比安慰剂治疗缺血性中风患者的经济性。方法:基于血塞通软胶囊的Ⅲ期对照试验和已发表的文献数据构建markov模型,模拟患者终身的质量调整生命年(quality-adjusted life year,QALY)和增量成本效果比(Incremental cost-effectiveness ratio ICER),并进行单因素敏感性分析和概率敏感性分析检验模型的不确定性。结果:基础分析结果显示,与安慰剂组相比,血塞通软胶囊在获得0.32个QALY且节约医疗成本,具有绝对优势,单因素敏感性分析和概率敏感性分析验证了模型的稳健性。单因素敏感性分析显示对模型结果影响程度最大的4个因素分别是mRS3-5首次住院成本、mRS0-2首次住院成本、mRS0-2的状态效用值及贴现率;概率敏感性分析显示在我国的意愿支付值之下血塞通软胶囊具有经济性的概率为100%。结论:与安慰剂相比,血塞通软胶囊在提升QALY的同时降低了相应的成本,对治疗我国缺血性中风患者具有经济性。展开更多
文摘Analysis of catchment Land use/Land cover (LULC) change is a vital tool in ensuring sustainable catchment management. The study analyzed land use/land cover changes in the Rwizi catchment, south western Uganda from 1989-2019 and projected the trend by 2040. Landsat images, field observations, key informant interviews and focus group discussions were used to collect data. Changes in cropland, forestland, built up area, grazing land, wetland and open water bodies were analyzed in ArcGIS version 10.2.2 and ERDAS IMAGINE 14 software and a Markov chain model. All the LULC classes increased in area except grazing land. Forest land and builtup area between 2009-2019 increased by 370.03% and 229.53% respectively. Projections revealed an increase in forest land and builtup area by 2030 and only built up area by 2040. LULCC in the catchment results from population pressure, reduced soil fertility and high value of agricultural products.
文摘This study examines vishing, a form of social engineering scam using voice communication to deceive individuals into revealing sensitive information or losing money. With the rise of smartphone usage, people are more susceptible to vishing attacks. The proposed Emoti-Shing model analyzes potential victims’ emotions using Hidden Markov Models to track vishing scams by examining the emotional content of phone call audio conversations. This approach aims to detect vishing scams using biological features of humans, specifically emotions, which cannot be easily masked or spoofed. Experimental results on 30 generated emotions indicate the potential for increased vishing scam detection through this approach.
基金National Natural Science Foundation of China(No.71401144)
文摘It is important to consider the changing states in hedging.The Markov regime-switching dynamic correlation multivariate stochastic volatility( MRS-DC-MSV) model was proposed to solve this issue. DC-MSV model and MRS-DC-MSV model were used to calculate the time-varying hedging ratios and compare the hedging performance. The Markov chain Monte Carlo( MCMC) method was used to estimate the parameters. The results showed that,there were obviously two economic states in Chinese financial market. Two models all did well in hedging,but the performance of MRS-DCMSV model was better. It could reduce risk by nearly 90%. Thus,in the hedging period,changing states is a factor that cannot be neglected.
文摘Retailing is a dynamic business domain where commodities and goods are sold in small quantities directly to the customers.It deals with the end user customers of a supply-chain network and therefore has to accommodate the needs and desires of a large group of customers over varied utilities.The volume and volatility of the business makes it one of the prospectivefields for analytical study and data modeling.This is also why customer segmentation drives a key role in multiple retail business decisions such as marketing budgeting,customer targeting,customized offers,value proposition etc.The segmentation could be on various aspects such as demographics,historic behavior or preferences based on the use cases.In this paper,historic retail transactional data is used to segment the custo-mers using K-Means clustering and the results are utilized to arrive at a transition matrix which is used to predict the cluster movements over the time period using Markov Model algorithm.This helps in calculating the futuristic value a segment or a customer brings to the business.Strategic marketing designs and budgeting can be implemented using these results.The study is specifically useful for large scale marketing in domains such as e-commerce,insurance or retailers to segment,profile and measure the customer lifecycle value over a short period of time.
文摘Modeling urban land-use dynamics is critical for urban experts’and infrastructure managers’planning.This study attempts to explore the land-use/land-cover(LULC)dynamics of Gondar using satellite images from 1984 to 2020.Markov-Chain and Cellular Automata(MC-CA)models have been recognized as performing well in predicting urban land-use change.However,only a few models work in Ethiopia in general,and no study in Gondar has applied this approach to study urban land-use patterns.Therefore,Gondar land-use/land cover changes of Gondar were predicted using the MC-CA model in IDRISI.The built-up area in Gondar city covered 1413 ha(3%of the total area)in 1984 and increased to 2380 ha(5%)in 1994;21153 ha(45.5%)in 2004;22622 ha(48.7%)in 2014;and 23427 ha(50.5%)in 2020.The area has been predicted to reach 57.5%in the 2050s,showing a faster increase that will cause a very vast loss of farmland.This will increase urban sprawl challenges as well as overall environmental disequilibrium in the preceding decade.Thus,innovative and careful structures and systems in urban planning are required to secure a sustainable urban future and to make our cities livable and competitive in the paradigm of sustainable cities.
基金This work was supported by the National Natural Science Foundation of China(62122063,62073268,U22B2036,11931015)the Young Star of Science and Technology in Shaanxi Province(2020KJXX-078)+1 种基金the National Science Fund for Distinguished Young Scholars(62025602)the XPLORER PRIZE。
文摘In this paper,the distributed stochastic model predictive control(MPC)is proposed for the noncooperative game problem of the discrete-time multi-player systems(MPSs)with the undirected Markov jump graph.To reflect the reality,the state and input constraints have been considered along with the external disturbances.An iterative algorithm is designed such that model predictive noncooperative game could converge to the socalledε-Nash equilibrium in a distributed manner.Sufficient conditions are established to guarantee the convergence of the proposed algorithm.In addition,a set of easy-to-check conditions are provided to ensure the mean-square uniform bounded stability of the underlying MPSs.Finally,a numerical example on a group of spacecrafts is studied to verify the effectiveness of the proposed method.
文摘目的基于Markov模型评价肺结节低剂量螺旋CT(LDCT)筛查的卫生经济学。方法利用2021年—2023年北京市某三甲医院的肺结节LDCT筛查数据和部分国外临床研究数据,采用成本效用分析方法,通过增量成本效用比(ICUR)确定优势筛查策略;使用R语言获得转移概率参数,利用TreeAge Pro 2011软件构建Markov模型。假设以我国10万名55岁及以上人群为肺结节筛查对象,模拟其疾病发展情况,并通过敏感性分析评价该模型的稳定性。结果成本效用分析显示,该模型经20次循环后,LDCT筛查策略的总成本为3543088618元,相较于不筛查策略的总成本增加了784130651元,额外获得了7996个质量调整生命年(QALY),每获得一个QALY需多花费98059.77元。采用WHO卫生经济学评价标准,LDCT筛查策略的ICUR大于1倍人均国内生产总值(GDP)但小于3倍人均GDP,为优势策略。敏感性分析显示,各变量在其敏感性分析范围内无论如何变化,都不会对ICUR产生较大影响,表明该模型具有较好的稳定性。结论在55岁及以上人群中开展每年一次肺结节LDCT筛查的ICUR小于3倍人均GDP,具有一定的经济学效用,该筛查策略有利于肺癌的“早发现、早诊断、早治疗”。
文摘目的:基于中国卫生服务体系角度评价血塞通软胶囊对比安慰剂治疗缺血性中风患者的经济性。方法:基于血塞通软胶囊的Ⅲ期对照试验和已发表的文献数据构建markov模型,模拟患者终身的质量调整生命年(quality-adjusted life year,QALY)和增量成本效果比(Incremental cost-effectiveness ratio ICER),并进行单因素敏感性分析和概率敏感性分析检验模型的不确定性。结果:基础分析结果显示,与安慰剂组相比,血塞通软胶囊在获得0.32个QALY且节约医疗成本,具有绝对优势,单因素敏感性分析和概率敏感性分析验证了模型的稳健性。单因素敏感性分析显示对模型结果影响程度最大的4个因素分别是mRS3-5首次住院成本、mRS0-2首次住院成本、mRS0-2的状态效用值及贴现率;概率敏感性分析显示在我国的意愿支付值之下血塞通软胶囊具有经济性的概率为100%。结论:与安慰剂相比,血塞通软胶囊在提升QALY的同时降低了相应的成本,对治疗我国缺血性中风患者具有经济性。
