BACKGROUND Drug utilization research has an important role in assisting the healthcare administration to know,compute,and refine the prescription whose principal objective is to enable the rational use of drugs.Resear...BACKGROUND Drug utilization research has an important role in assisting the healthcare administration to know,compute,and refine the prescription whose principal objective is to enable the rational use of drugs.Research in developing nations relating to the cost of treatment is scarce when compared with developed countries.Thus,the drug utilization research studies from developing nations are most needed,and their number has been growing.AIM To evaluate patterns of utilization of antipsychotic drugs and direct medical cost analysis in patients newly diagnosed with schizophrenia.METHODS The present study was observational in type and based on a retrospective cohort to evaluate patterns of utilization of antipsychotic drugs using World Health Organization(WHO)core prescribing indicators and anatomical therapeutic chemical/defined daily dose indicators.We also calculated direct medical costs for a period of 6 months.RESULTS This study has found that atypical antipsychotics are the mainstay of treatment for schizophrenia in every age group and subcategories of schizophrenia.The evaluation based on WHO prescribing indicators showed a low average number of drugs per prescription and low prescribing frequency of antipsychotics from the National List of Essential Medicines 2015 and the WHO Essential Medicines List 2019.The total mean drug cost of our study was 1396 Indian rupees.The total mean cost due to the investigation in our study was 1017.34 Indian rupees.Therefore,the total mean direct medical cost incurred on patients in our study was 4337.28 Indian rupees.CONCLUSION The information from the present study can be used for reviewing and updating treatment policy at the institutional level.展开更多
AIM:To compare laparoscopic pancreaticoduodenectomy(TLPD) during the initial learning curve with open pancreaticoduodenectomy in terms of outcome and costs.METHODS:This is a retrospective review of the consecutive pat...AIM:To compare laparoscopic pancreaticoduodenectomy(TLPD) during the initial learning curve with open pancreaticoduodenectomy in terms of outcome and costs.METHODS:This is a retrospective review of the consecutive patients who underwent TLPD between December 2009 and April 2014 at our institution.The experiences of the initial 15 consecutive TLPD cases,considered as the initial learning curve of each surgeon,were compared with the same number of consecutive laparotomy cases with the same spectrum of diseases in terms of outcome and costs.Laparoscopic patients with conversion to open surgery were excluded.Preoperative demographic and comorbidity data were obtained.Postoperative data on intestinal movement,pain score,mortality,complications,and costs were obtained for analysis.Complications related to surgery included pneumonia, intra-abdominal abscess,postpancreatectomy hemorrhage,biliary leak,pancreatic fistula,delayed gastric emptying,and multiple organ dysfunction syndrome.The total costs consisted of cost of surgery,anesthesia,and admission examination.RESULTS:A total of 60 patients,including 30 consecutive laparoscopic cases and 30 consecutive open cases,were enrolled for review.Demographic and comorbidity characteristics of the two groups were similar.TLPD required a significantly longer operative time(513.17 ± 56.13 min vs 371.67 ± 85.53 min,P < 0.001).The TLPD group had significantly fewer mean numbers of days until bowel sounds returned(2.03 ± 0.55 d vs 3.83 ± 0.59 d,P < 0.001) and exhaustion(4.17 ± 0.75 d vs 5.37 ± 0.81 d,P < 0.001).The mean visual analogue score on postoperative day 4 was less in the TLPD group(3.5 ± 9.7 vs 4.47 ± 1.11,P < 0.05).No differences in surgery-related morbidities and mortality were observed between the two groups.Patients in the TLPD group recovered more quickly and required a shorter hospital stay after surgery(9.97 ± 3.74 d vs 11.87 ± 4.72 d,P < 0.05).A significant difference in the total cost was found between the two groups(TLPD 81317.43 ± 2027.60 RMB vs laparotomy 78433.23 ± 5788.12 RMB,P < 0.05).TLPD had a statistically higher cost for both surgery(24732.13 ± 929.28 RMB vs 19317.53 ± 795.94 RMB,P < 0.001)and anesthesia(6192.37 ± 272.77 RMB vs 5184.10 ± 146.93 RMB,P < 0.001),but a reduced cost for admission examination(50392.93 ± 1761.22 RMB vs 53931.60 ± 5556.94 RMB,P < 0.05).CONCLUSION:TLPD is safe when performed by experienced pancreatobiliary surgeons during the initial learning curve,but has a higher cost than open pancreaticoduodenectomy.展开更多
Transportation Problems (TP), as is known, are a basic network problem which can be formulated as a Linear Programming Problem (LPP). Transportation networks are built up in order to save transportation cost. In the s...Transportation Problems (TP), as is known, are a basic network problem which can be formulated as a Linear Programming Problem (LPP). Transportation networks are built up in order to save transportation cost. In the solution procedure of a TP, finding an Initial Basic Feasible Solution (IBFS) is necessary to obtain the optimal solution. Optimality gives us the optimal route that prompts either most extreme benefit or least aggregate cost whichever is required. In this research paper, a new method named Least Cost Mean Method is proposed to obtain a better IBFS where row penalty and column penalty is brought out by the mean of lowest and next lowest cost of each row and each column of the cost matrix. The method is illustrated with numerical examples. To verify the performance of the proposed method, a comparative study is also carried out and observed that it is computationally easier and yielding comparatively better solution.展开更多
An analysis applied to an existing building considering the whole service life, regulated or, if any, measured, of energy/technological upgrading action does not only require initial investments to be taken into accou...An analysis applied to an existing building considering the whole service life, regulated or, if any, measured, of energy/technological upgrading action does not only require initial investments to be taken into account. Of course, such investments are significant and will have to be considered at a first stage, but it is not the only aspect to be considered. Provisions of Construction Procurement Guidance, No.7 Whole Life Costs state： ＂All procurement must be made solely on the basis of value for money in terms of the optimum combination of global costs--and not only initial investment costs--and quality to meet the user＇s requirements＂.展开更多
In this paper,we present a novel initial costates solver for initializing time-optimal trajectory problems in relative motion with continuous low thrust.The proposed solver consists of two primary components:training ...In this paper,we present a novel initial costates solver for initializing time-optimal trajectory problems in relative motion with continuous low thrust.The proposed solver consists of two primary components:training a Multilayer Perceptron(MLP)for generating reference sequence and Time of Flight(TOF)to the target,and deriving a system of linear algebraic equations for obtaining the initial costates.To overcome the challenge of generating training samples for the MLP,the backward generation method is proposed to obtain five different training databases.The training database and sample form are determined by analyzing the input and output correlation using the Pearson correlation coefficient.The best-performing MLP is obtained by analyzing the training results with various hyper-parameter combinations.A reference sequence starting from the initial states is obtained by integrating forward with the near-optimal control vector from the output of MLP.Finally,a system of linear algebraic equations for estimating the initial costates is derived using the reference sequence and the necessary conditions for optimality.Simulation results demonstrate that the proposed initial costates solver improves the convergence ratio and reduce the function calls of the shooting function.Furthermore,Monte-Carlo simulation illustrates that the initial costates solver is applicable to different initial velocities,demonstrating excellent generalization ability.展开更多
The release of a new artificial intelligence(AI)model,ironically,evokes a biblical memory.What has transpired in the past few days echoes the biblical story of David versus Goliath,in which the massive and wellarmed G...The release of a new artificial intelligence(AI)model,ironically,evokes a biblical memory.What has transpired in the past few days echoes the biblical story of David versus Goliath,in which the massive and wellarmed Goliath is defeated by the comparatively puny David,who comes to the battle with only his staff and sling.展开更多
During the initial impoundment period of a canyon-shaped reservoir,the water body fluctuated violently regarding water level,hydrological condition,and thermal stratification.These variations may alter the structure o...During the initial impoundment period of a canyon-shaped reservoir,the water body fluctuated violently regarding water level,hydrological condition,and thermal stratification.These variations may alter the structure of phytoplankton community,resulting in algal blooms and seriously threatening the ecological security of the reservoir.It is of great significance to understand the continuous changes of phytoplankton in the initial impoundment period for the protection of reservoir water quality.Therefore,a two-year in-situ monitoring study was conducted on water quality and phytoplankton in a representative canyonshaped reservoir named Sanhekou and the interannual changes of phytoplankton community and its response to environmental changes during the initial impoundment period were discussed at taxonomic versus functional classification levels.The results showed that the total nitrogen and permanganate index levels were relatively high in the first year due to rapid water storage and heavy rainfall input,and the more stable hydrological conditions in the second year promoted the increase of algae density and the transformation of community,and the proportion of cyanobacteria increased significantly.The succession order of phytoplankton in the first year of the initial impoundment periodwas Chlorophyta-Bacillariophyta-Chlorophyta,or J/F/X1-P/MP/W1-A/X1/MP,respectively.And the succession order in the second year was Cyanobacteria/Chlorophyta-Bacillariophyta-Chlorophyta,or L_(M)/G/P-P/A/X1-X1/J/G.Water temperature,relativewater column stability,mixing depth,and pHwere crucial factors affecting phytoplankton community succession.This study revealed the interannual succession law and driving factors of phytoplankton in the initial impoundment period and provided an important reference for the operation management and ecological protection of canyon-shaped reservoirs.展开更多
Ultra-low emission of nitrogen oxide(NO_(x))is an irreversible trend for the development of waste-to-energy industry.But traditional approaches to remove NO_(x) face significant challenge s,such as low denitration eff...Ultra-low emission of nitrogen oxide(NO_(x))is an irreversible trend for the development of waste-to-energy industry.But traditional approaches to remove NO_(x) face significant challenge s,such as low denitration efficiency,complex denitration system,and high investment and operating cost.Here we put forward a novel polymer non-catalytic reduction(PNCR)technology that utilized a new type of polymer agent to remove NO_(x),and the proposed PNCR technology was applied to the existing waste-to-energy plant to test the denitration performance.The PNCR technology demonstrated excellent denitration performance with a NO_(x) emission concentration of<100 mg/Nm^(3) and high denitration efficiency of>75%at the temperature range of 800-900℃,which showed the application feasibility even on the complex and unstable industrial operating conditions.In addition,PNCR and hybrid polymer/selective non-catalytic reduction(PNCR/SNCR)technology possessed remarkable economic advantages including low investment fee and low operating cost of<10 CNY per ton of municipal solid waste(MSW)compared with selective catalytic reduction(SCR)technology.The excellent denitration performance of PNCR technology forebodes a broad industrial application prospect in the field of flue gas cleaning for waste-to-energy plants.展开更多
Accuracy allocation is crucial in the accuracy design of machining tools.Current accuracy allocation methods primarily focus on positional deviation,with little consideration for tool direction deviation.To address th...Accuracy allocation is crucial in the accuracy design of machining tools.Current accuracy allocation methods primarily focus on positional deviation,with little consideration for tool direction deviation.To address this issue,we propose a geometric error cost sensitivity-based accuracy allocation method for five-axis machine tools.A geometric error model consisting of 4l error components is constructed based on homogeneous transformation matrices.Volumetric points with positional and tool direction deviations are randomly sampled to evaluate the accuracy of the machine tool.The sensitivity of each error component at these sampling points is analyzed using the Sobol method.To balance the needs of geometric precision and manufacturing cost,a geometric error cost sensitivity function is developed to estimate the required cost.By allocating error components affecting tool direction deviation first and the remaining components second,this allocation scheme ensures that both deviations meet the requirements.We also perform numerical simulation of a BC-type(B-axis and C-axis type)five-axis machine tool to validate the method.The results show that the new allocation scheme reduces the total geometric error cost by 27.8%compared to a uniform allocation scheme,and yields the same positional and tool direction machining accuracies.展开更多
Evaluation of hydromechanical shear behavior of unsaturated soils is still a challenging issue. The time and cost needed for conducting precise experimental investigation on shear behavior of unsaturated soils have en...Evaluation of hydromechanical shear behavior of unsaturated soils is still a challenging issue. The time and cost needed for conducting precise experimental investigation on shear behavior of unsaturated soils have encouraged several investigators to develop analytical, empirical, or semi-empirical models for predicting the shear behavior of unsaturated soils. However, most of the previously proposed models are for specimens subjected to the isotropic state of stress, without considering the effect of initial shear stress. In this study, a hydromechanical constitutive model is proposed for unsaturated collapsible soils during shearing, with consideration of the effect of the initial shear stress. The model implements an effective stress-based disturbed state concept (DSC) to predict the stress-strain behavior of the soil. Accordingly, material/state variables were defined for both the start of the shearing stage and the critical state of the soil. A series of laboratory tests was performed using a fully automated unsaturated triaxial device to verify the proposed model. The experimental program included 23 suction-controlled unsaturated triaxial shear tests on reconstituted specimens of Gorgan clayey loess wetted to different levels of suctions under both isotropic and anisotropic stress states. The results show excellent agreement between the prediction by the proposed model and the experimental results.展开更多
BACKGROUND Coronavirus disease 2019(COVID-19)is strongly associated with an increased risk of thrombotic events,including severe outcomes such as pulmonary embolism.Elevated D-dimer levels are a critical biomarker for...BACKGROUND Coronavirus disease 2019(COVID-19)is strongly associated with an increased risk of thrombotic events,including severe outcomes such as pulmonary embolism.Elevated D-dimer levels are a critical biomarker for assessing this risk.In Gabon,early implementation of anticoagulation therapy and D-dimer testing has been crucial in managing COVID-19.This study hypothesizes that elevated Ddimer levels are linked to increased COVID-19 severity.AIM To determine the impact of D-dimer levels on COVID-19 severity and their role in guiding clinical decisions.METHODS This retrospective study analyzed COVID-19 patients admitted to two hospitals in Gabon between March 2020 and December 2023.The study included patients with confirmed COVID-19 diagnoses and available D-dimer measurements at admission.Data on demographics,clinical outcomes,D-dimer levels,and healthcare costs were collected.COVID-19 severity was classified as non-severe(outpatients)or severe(inpatients).A multivariable logistic regression model was used to assess the relationship between D-dimer levels and disease severity,with adjusted odds ratios(OR)and 95%CI.RESULTS A total of 3004 patients were included,with a mean age of 50.17 years,and the majority were female(53.43%).Elevated D-dimer levels were found in 65.81%of patients,and 57.21%of these experienced severe COVID-19.Univariate analysis showed that patients with elevated D-dimer levels had 3.33 times higher odds of severe COVID-19(OR=3.33,95%CI:2.84-3.92,P<0.001),and this association remained significant in the multivariable analysis,adjusted for age,sex,and year of collection.The financial analysis revealed a substantial burden,particularly for uninsured patients.CONCLUSION D-dimer predicts COVID-19 severity and guides treatment,but the high cost of anticoagulant therapy highlights the need for policies ensuring affordable access in resource-limited settings like Gabon.展开更多
We study the two-dimensional(2D)Cauchy problem of nonhomogeneous Boussinesq system for magnetohydrodynamics convection without heat diffusion in the whole plane.Based on delicate weighted estimates,we derive the globa...We study the two-dimensional(2D)Cauchy problem of nonhomogeneous Boussinesq system for magnetohydrodynamics convection without heat diffusion in the whole plane.Based on delicate weighted estimates,we derive the global existence and uniqueness of strong solutions.In particular,the initial data can be arbitrarily large and the initial density may contain vacuum states and even have compact support.展开更多
The new edition of the International Production Cost Comparison (IPCC) from ITMF has been published.The report benchmarks manufacturing costs for a range of textile products along the primary textile value chain,disag...The new edition of the International Production Cost Comparison (IPCC) from ITMF has been published.The report benchmarks manufacturing costs for a range of textile products along the primary textile value chain,disaggregated by key cost components at each production stage.展开更多
The ease of accessing a virtually unlimited pool of resources makes Infrastructure as a Service (IaaS) clouds an ideal platform for running data-intensive workflow applications comprising hundreds of computational tas...The ease of accessing a virtually unlimited pool of resources makes Infrastructure as a Service (IaaS) clouds an ideal platform for running data-intensive workflow applications comprising hundreds of computational tasks. However, executing scientific workflows in IaaS cloud environments poses significant challenges due to conflicting objectives, such as minimizing execution time (makespan) and reducing resource utilization costs. This study responds to the increasing need for efficient and adaptable optimization solutions in dynamic and complex environments, which are critical for meeting the evolving demands of modern users and applications. This study presents an innovative multi-objective approach for scheduling scientific workflows in IaaS cloud environments. The proposed algorithm, MOS-MWMC, aims to minimize total execution time (makespan) and resource utilization costs by leveraging key features of virtual machine instances, such as a high number of cores and fast local SSD storage. By integrating realistic simulations based on the WRENCH framework, the method effectively dimensions the cloud infrastructure and optimizes resource usage. Experimental results highlight the superiority of MOS-MWMC compared to benchmark algorithms HEFT and Max-Min. The Pareto fronts obtained for the CyberShake, Epigenomics, and Montage workflows demonstrate closer proximity to the optimal front, confirming the algorithm’s ability to balance conflicting objectives. This study contributes to optimizing scientific workflows in complex environments by providing solutions tailored to specific user needs while minimizing costs and execution times.展开更多
COVID-19 placed increased pressure and urgency for effective cost management,resulting in unprecedented financial strains for hospitals.The pandemic also became a catalyst for accelerating digital transformation to im...COVID-19 placed increased pressure and urgency for effective cost management,resulting in unprecedented financial strains for hospitals.The pandemic also became a catalyst for accelerating digital transformation to improve operations and services in the healthcare industry.Morningdale Hospital is a large and reputable general hospital with a long history in the U.K.You are an intern in the Finance Department of the Hospital.The CEO has asked you to complete a patient-level cost analysis of endoscopic procedures in the Gastrointestinal Department.In your final report,you plan to include a SWOT analysis and a cost analysis using Activity-Based Costing accounting method.展开更多
The purpose of this article is to analyze the advantages and application paths of BIM5D technology in the cost control of completed houses.In the research phase,based on the reading of literature and the combination o...The purpose of this article is to analyze the advantages and application paths of BIM5D technology in the cost control of completed houses.In the research phase,based on the reading of literature and the combination of project materials,the advantages of BIM5D in the cost control project of completed houses are analyzed after introducing the cost control of completed houses and the connotation of BIM5D technology.Finally,this article starts from multiple perspectives,including BIM5D modeling,cost deviation analysis under dynamic cost control,etc.,and finally forms a relatively systematic and complete BIM cost control technology system.It is hoped that this article can provide technical reference value for China’s completed housing projects,promote the improvement of the project team’s cost control level,obtain considerable economic benefits based on completing project construction with quality and quantity,and enhance the competitiveness of enterprises.展开更多
Against the backdrop of the increasingly complex construction market environment,the whole-process cost management of agency-built projects faces issues such as cost overruns and insufficient management efficiency due...Against the backdrop of the increasingly complex construction market environment,the whole-process cost management of agency-built projects faces issues such as cost overruns and insufficient management efficiency due to the numerous stages and high technical requirements involved.This paper focuses on the key stages of whole-process cost management in agency-built projects,including project initiation,design,construction,and completion.It proposes strategies to optimize the cost management process and enhance management efficiency,providing theoretical support and practical guidance for the whole-process cost management under the agency-built model.展开更多
The commercialization of perovskite solar cells(PSCs)has garnered worldwide attention and many efforts were devoted on the improvement of efficiency and stability.Here,we estimated the cost effectivities of PSCs based...The commercialization of perovskite solar cells(PSCs)has garnered worldwide attention and many efforts were devoted on the improvement of efficiency and stability.Here,we estimated the cost effectivities of PSCs based on the current industrial condition.Through the analysis of current process,the manufacturing cost and the levelized cost of electricity(LCOE)of PSCs is estimated as 0.57$W^(−1) and 18-22 US cents(kWh)^(−1),respectively,and we demonstrate the materials cost shares 70%of the total cost.Sensitivity analysis indicates that the improvement of efficiency,yield and decrease in materials cost significantly reduce the cost of the modules.Analysis of the module cost and LCOE indicates that the PSCs have the potential to outperform the silicon solar cells in the condition of over 25%efficiency and 25-year lifetime in future.To achieve this target,it is essential to further refine the fabrication processes of each layer in the module,develop stable inorganic transport materials,and precisely control material formation and processing at the microscale and nanoscale to enhance charge transport.展开更多
文摘BACKGROUND Drug utilization research has an important role in assisting the healthcare administration to know,compute,and refine the prescription whose principal objective is to enable the rational use of drugs.Research in developing nations relating to the cost of treatment is scarce when compared with developed countries.Thus,the drug utilization research studies from developing nations are most needed,and their number has been growing.AIM To evaluate patterns of utilization of antipsychotic drugs and direct medical cost analysis in patients newly diagnosed with schizophrenia.METHODS The present study was observational in type and based on a retrospective cohort to evaluate patterns of utilization of antipsychotic drugs using World Health Organization(WHO)core prescribing indicators and anatomical therapeutic chemical/defined daily dose indicators.We also calculated direct medical costs for a period of 6 months.RESULTS This study has found that atypical antipsychotics are the mainstay of treatment for schizophrenia in every age group and subcategories of schizophrenia.The evaluation based on WHO prescribing indicators showed a low average number of drugs per prescription and low prescribing frequency of antipsychotics from the National List of Essential Medicines 2015 and the WHO Essential Medicines List 2019.The total mean drug cost of our study was 1396 Indian rupees.The total mean cost due to the investigation in our study was 1017.34 Indian rupees.Therefore,the total mean direct medical cost incurred on patients in our study was 4337.28 Indian rupees.CONCLUSION The information from the present study can be used for reviewing and updating treatment policy at the institutional level.
文摘AIM:To compare laparoscopic pancreaticoduodenectomy(TLPD) during the initial learning curve with open pancreaticoduodenectomy in terms of outcome and costs.METHODS:This is a retrospective review of the consecutive patients who underwent TLPD between December 2009 and April 2014 at our institution.The experiences of the initial 15 consecutive TLPD cases,considered as the initial learning curve of each surgeon,were compared with the same number of consecutive laparotomy cases with the same spectrum of diseases in terms of outcome and costs.Laparoscopic patients with conversion to open surgery were excluded.Preoperative demographic and comorbidity data were obtained.Postoperative data on intestinal movement,pain score,mortality,complications,and costs were obtained for analysis.Complications related to surgery included pneumonia, intra-abdominal abscess,postpancreatectomy hemorrhage,biliary leak,pancreatic fistula,delayed gastric emptying,and multiple organ dysfunction syndrome.The total costs consisted of cost of surgery,anesthesia,and admission examination.RESULTS:A total of 60 patients,including 30 consecutive laparoscopic cases and 30 consecutive open cases,were enrolled for review.Demographic and comorbidity characteristics of the two groups were similar.TLPD required a significantly longer operative time(513.17 ± 56.13 min vs 371.67 ± 85.53 min,P < 0.001).The TLPD group had significantly fewer mean numbers of days until bowel sounds returned(2.03 ± 0.55 d vs 3.83 ± 0.59 d,P < 0.001) and exhaustion(4.17 ± 0.75 d vs 5.37 ± 0.81 d,P < 0.001).The mean visual analogue score on postoperative day 4 was less in the TLPD group(3.5 ± 9.7 vs 4.47 ± 1.11,P < 0.05).No differences in surgery-related morbidities and mortality were observed between the two groups.Patients in the TLPD group recovered more quickly and required a shorter hospital stay after surgery(9.97 ± 3.74 d vs 11.87 ± 4.72 d,P < 0.05).A significant difference in the total cost was found between the two groups(TLPD 81317.43 ± 2027.60 RMB vs laparotomy 78433.23 ± 5788.12 RMB,P < 0.05).TLPD had a statistically higher cost for both surgery(24732.13 ± 929.28 RMB vs 19317.53 ± 795.94 RMB,P < 0.001)and anesthesia(6192.37 ± 272.77 RMB vs 5184.10 ± 146.93 RMB,P < 0.001),but a reduced cost for admission examination(50392.93 ± 1761.22 RMB vs 53931.60 ± 5556.94 RMB,P < 0.05).CONCLUSION:TLPD is safe when performed by experienced pancreatobiliary surgeons during the initial learning curve,but has a higher cost than open pancreaticoduodenectomy.
文摘Transportation Problems (TP), as is known, are a basic network problem which can be formulated as a Linear Programming Problem (LPP). Transportation networks are built up in order to save transportation cost. In the solution procedure of a TP, finding an Initial Basic Feasible Solution (IBFS) is necessary to obtain the optimal solution. Optimality gives us the optimal route that prompts either most extreme benefit or least aggregate cost whichever is required. In this research paper, a new method named Least Cost Mean Method is proposed to obtain a better IBFS where row penalty and column penalty is brought out by the mean of lowest and next lowest cost of each row and each column of the cost matrix. The method is illustrated with numerical examples. To verify the performance of the proposed method, a comparative study is also carried out and observed that it is computationally easier and yielding comparatively better solution.
文摘An analysis applied to an existing building considering the whole service life, regulated or, if any, measured, of energy/technological upgrading action does not only require initial investments to be taken into account. Of course, such investments are significant and will have to be considered at a first stage, but it is not the only aspect to be considered. Provisions of Construction Procurement Guidance, No.7 Whole Life Costs state： ＂All procurement must be made solely on the basis of value for money in terms of the optimum combination of global costs--and not only initial investment costs--and quality to meet the user＇s requirements＂.
基金This study was funded by the National Natural Science Foundation of China(Nos.11972077 and 12272039).
文摘In this paper,we present a novel initial costates solver for initializing time-optimal trajectory problems in relative motion with continuous low thrust.The proposed solver consists of two primary components:training a Multilayer Perceptron(MLP)for generating reference sequence and Time of Flight(TOF)to the target,and deriving a system of linear algebraic equations for obtaining the initial costates.To overcome the challenge of generating training samples for the MLP,the backward generation method is proposed to obtain five different training databases.The training database and sample form are determined by analyzing the input and output correlation using the Pearson correlation coefficient.The best-performing MLP is obtained by analyzing the training results with various hyper-parameter combinations.A reference sequence starting from the initial states is obtained by integrating forward with the near-optimal control vector from the output of MLP.Finally,a system of linear algebraic equations for estimating the initial costates is derived using the reference sequence and the necessary conditions for optimality.Simulation results demonstrate that the proposed initial costates solver improves the convergence ratio and reduce the function calls of the shooting function.Furthermore,Monte-Carlo simulation illustrates that the initial costates solver is applicable to different initial velocities,demonstrating excellent generalization ability.
文摘The release of a new artificial intelligence(AI)model,ironically,evokes a biblical memory.What has transpired in the past few days echoes the biblical story of David versus Goliath,in which the massive and wellarmed Goliath is defeated by the comparatively puny David,who comes to the battle with only his staff and sling.
基金supported by the National Key R&D Program of China(No.2022YFC3203602)the Natural Science Foundation of China(No.52370018)+1 种基金Shaanxi Provincial Youth Innovation Team Project(No.22JP040)Shaanxi Provincial Key Scientific and Technological Innovation Team(No.2023-CX-TD-32).
文摘During the initial impoundment period of a canyon-shaped reservoir,the water body fluctuated violently regarding water level,hydrological condition,and thermal stratification.These variations may alter the structure of phytoplankton community,resulting in algal blooms and seriously threatening the ecological security of the reservoir.It is of great significance to understand the continuous changes of phytoplankton in the initial impoundment period for the protection of reservoir water quality.Therefore,a two-year in-situ monitoring study was conducted on water quality and phytoplankton in a representative canyonshaped reservoir named Sanhekou and the interannual changes of phytoplankton community and its response to environmental changes during the initial impoundment period were discussed at taxonomic versus functional classification levels.The results showed that the total nitrogen and permanganate index levels were relatively high in the first year due to rapid water storage and heavy rainfall input,and the more stable hydrological conditions in the second year promoted the increase of algae density and the transformation of community,and the proportion of cyanobacteria increased significantly.The succession order of phytoplankton in the first year of the initial impoundment periodwas Chlorophyta-Bacillariophyta-Chlorophyta,or J/F/X1-P/MP/W1-A/X1/MP,respectively.And the succession order in the second year was Cyanobacteria/Chlorophyta-Bacillariophyta-Chlorophyta,or L_(M)/G/P-P/A/X1-X1/J/G.Water temperature,relativewater column stability,mixing depth,and pHwere crucial factors affecting phytoplankton community succession.This study revealed the interannual succession law and driving factors of phytoplankton in the initial impoundment period and provided an important reference for the operation management and ecological protection of canyon-shaped reservoirs.
基金supported by the National Natural Science Foundation of China(No.92367107)。
文摘Ultra-low emission of nitrogen oxide(NO_(x))is an irreversible trend for the development of waste-to-energy industry.But traditional approaches to remove NO_(x) face significant challenge s,such as low denitration efficiency,complex denitration system,and high investment and operating cost.Here we put forward a novel polymer non-catalytic reduction(PNCR)technology that utilized a new type of polymer agent to remove NO_(x),and the proposed PNCR technology was applied to the existing waste-to-energy plant to test the denitration performance.The PNCR technology demonstrated excellent denitration performance with a NO_(x) emission concentration of<100 mg/Nm^(3) and high denitration efficiency of>75%at the temperature range of 800-900℃,which showed the application feasibility even on the complex and unstable industrial operating conditions.In addition,PNCR and hybrid polymer/selective non-catalytic reduction(PNCR/SNCR)technology possessed remarkable economic advantages including low investment fee and low operating cost of<10 CNY per ton of municipal solid waste(MSW)compared with selective catalytic reduction(SCR)technology.The excellent denitration performance of PNCR technology forebodes a broad industrial application prospect in the field of flue gas cleaning for waste-to-energy plants.
基金supported by the Key R&D Program of Zhejiang Province(Nos.2023C01166 and 2024SJCZX0046)the Zhejiang Provincial Natural Science Foundation of China(Nos.LDT23E05013E05 and LD24E050009)the Natural Science Foundation of Ningbo(No.2021J150),China.
文摘Accuracy allocation is crucial in the accuracy design of machining tools.Current accuracy allocation methods primarily focus on positional deviation,with little consideration for tool direction deviation.To address this issue,we propose a geometric error cost sensitivity-based accuracy allocation method for five-axis machine tools.A geometric error model consisting of 4l error components is constructed based on homogeneous transformation matrices.Volumetric points with positional and tool direction deviations are randomly sampled to evaluate the accuracy of the machine tool.The sensitivity of each error component at these sampling points is analyzed using the Sobol method.To balance the needs of geometric precision and manufacturing cost,a geometric error cost sensitivity function is developed to estimate the required cost.By allocating error components affecting tool direction deviation first and the remaining components second,this allocation scheme ensures that both deviations meet the requirements.We also perform numerical simulation of a BC-type(B-axis and C-axis type)five-axis machine tool to validate the method.The results show that the new allocation scheme reduces the total geometric error cost by 27.8%compared to a uniform allocation scheme,and yields the same positional and tool direction machining accuracies.
文摘Evaluation of hydromechanical shear behavior of unsaturated soils is still a challenging issue. The time and cost needed for conducting precise experimental investigation on shear behavior of unsaturated soils have encouraged several investigators to develop analytical, empirical, or semi-empirical models for predicting the shear behavior of unsaturated soils. However, most of the previously proposed models are for specimens subjected to the isotropic state of stress, without considering the effect of initial shear stress. In this study, a hydromechanical constitutive model is proposed for unsaturated collapsible soils during shearing, with consideration of the effect of the initial shear stress. The model implements an effective stress-based disturbed state concept (DSC) to predict the stress-strain behavior of the soil. Accordingly, material/state variables were defined for both the start of the shearing stage and the critical state of the soil. A series of laboratory tests was performed using a fully automated unsaturated triaxial device to verify the proposed model. The experimental program included 23 suction-controlled unsaturated triaxial shear tests on reconstituted specimens of Gorgan clayey loess wetted to different levels of suctions under both isotropic and anisotropic stress states. The results show excellent agreement between the prediction by the proposed model and the experimental results.
文摘BACKGROUND Coronavirus disease 2019(COVID-19)is strongly associated with an increased risk of thrombotic events,including severe outcomes such as pulmonary embolism.Elevated D-dimer levels are a critical biomarker for assessing this risk.In Gabon,early implementation of anticoagulation therapy and D-dimer testing has been crucial in managing COVID-19.This study hypothesizes that elevated Ddimer levels are linked to increased COVID-19 severity.AIM To determine the impact of D-dimer levels on COVID-19 severity and their role in guiding clinical decisions.METHODS This retrospective study analyzed COVID-19 patients admitted to two hospitals in Gabon between March 2020 and December 2023.The study included patients with confirmed COVID-19 diagnoses and available D-dimer measurements at admission.Data on demographics,clinical outcomes,D-dimer levels,and healthcare costs were collected.COVID-19 severity was classified as non-severe(outpatients)or severe(inpatients).A multivariable logistic regression model was used to assess the relationship between D-dimer levels and disease severity,with adjusted odds ratios(OR)and 95%CI.RESULTS A total of 3004 patients were included,with a mean age of 50.17 years,and the majority were female(53.43%).Elevated D-dimer levels were found in 65.81%of patients,and 57.21%of these experienced severe COVID-19.Univariate analysis showed that patients with elevated D-dimer levels had 3.33 times higher odds of severe COVID-19(OR=3.33,95%CI:2.84-3.92,P<0.001),and this association remained significant in the multivariable analysis,adjusted for age,sex,and year of collection.The financial analysis revealed a substantial burden,particularly for uninsured patients.CONCLUSION D-dimer predicts COVID-19 severity and guides treatment,but the high cost of anticoagulant therapy highlights the need for policies ensuring affordable access in resource-limited settings like Gabon.
文摘We study the two-dimensional(2D)Cauchy problem of nonhomogeneous Boussinesq system for magnetohydrodynamics convection without heat diffusion in the whole plane.Based on delicate weighted estimates,we derive the global existence and uniqueness of strong solutions.In particular,the initial data can be arbitrarily large and the initial density may contain vacuum states and even have compact support.
文摘The new edition of the International Production Cost Comparison (IPCC) from ITMF has been published.The report benchmarks manufacturing costs for a range of textile products along the primary textile value chain,disaggregated by key cost components at each production stage.
文摘The ease of accessing a virtually unlimited pool of resources makes Infrastructure as a Service (IaaS) clouds an ideal platform for running data-intensive workflow applications comprising hundreds of computational tasks. However, executing scientific workflows in IaaS cloud environments poses significant challenges due to conflicting objectives, such as minimizing execution time (makespan) and reducing resource utilization costs. This study responds to the increasing need for efficient and adaptable optimization solutions in dynamic and complex environments, which are critical for meeting the evolving demands of modern users and applications. This study presents an innovative multi-objective approach for scheduling scientific workflows in IaaS cloud environments. The proposed algorithm, MOS-MWMC, aims to minimize total execution time (makespan) and resource utilization costs by leveraging key features of virtual machine instances, such as a high number of cores and fast local SSD storage. By integrating realistic simulations based on the WRENCH framework, the method effectively dimensions the cloud infrastructure and optimizes resource usage. Experimental results highlight the superiority of MOS-MWMC compared to benchmark algorithms HEFT and Max-Min. The Pareto fronts obtained for the CyberShake, Epigenomics, and Montage workflows demonstrate closer proximity to the optimal front, confirming the algorithm’s ability to balance conflicting objectives. This study contributes to optimizing scientific workflows in complex environments by providing solutions tailored to specific user needs while minimizing costs and execution times.
文摘COVID-19 placed increased pressure and urgency for effective cost management,resulting in unprecedented financial strains for hospitals.The pandemic also became a catalyst for accelerating digital transformation to improve operations and services in the healthcare industry.Morningdale Hospital is a large and reputable general hospital with a long history in the U.K.You are an intern in the Finance Department of the Hospital.The CEO has asked you to complete a patient-level cost analysis of endoscopic procedures in the Gastrointestinal Department.In your final report,you plan to include a SWOT analysis and a cost analysis using Activity-Based Costing accounting method.
文摘The purpose of this article is to analyze the advantages and application paths of BIM5D technology in the cost control of completed houses.In the research phase,based on the reading of literature and the combination of project materials,the advantages of BIM5D in the cost control project of completed houses are analyzed after introducing the cost control of completed houses and the connotation of BIM5D technology.Finally,this article starts from multiple perspectives,including BIM5D modeling,cost deviation analysis under dynamic cost control,etc.,and finally forms a relatively systematic and complete BIM cost control technology system.It is hoped that this article can provide technical reference value for China’s completed housing projects,promote the improvement of the project team’s cost control level,obtain considerable economic benefits based on completing project construction with quality and quantity,and enhance the competitiveness of enterprises.
文摘Against the backdrop of the increasingly complex construction market environment,the whole-process cost management of agency-built projects faces issues such as cost overruns and insufficient management efficiency due to the numerous stages and high technical requirements involved.This paper focuses on the key stages of whole-process cost management in agency-built projects,including project initiation,design,construction,and completion.It proposes strategies to optimize the cost management process and enhance management efficiency,providing theoretical support and practical guidance for the whole-process cost management under the agency-built model.
基金National Key R&D Program of China(No.2021YFB3800068)the National Natural Science Foundation of China(No.U21A20171).
文摘The commercialization of perovskite solar cells(PSCs)has garnered worldwide attention and many efforts were devoted on the improvement of efficiency and stability.Here,we estimated the cost effectivities of PSCs based on the current industrial condition.Through the analysis of current process,the manufacturing cost and the levelized cost of electricity(LCOE)of PSCs is estimated as 0.57$W^(−1) and 18-22 US cents(kWh)^(−1),respectively,and we demonstrate the materials cost shares 70%of the total cost.Sensitivity analysis indicates that the improvement of efficiency,yield and decrease in materials cost significantly reduce the cost of the modules.Analysis of the module cost and LCOE indicates that the PSCs have the potential to outperform the silicon solar cells in the condition of over 25%efficiency and 25-year lifetime in future.To achieve this target,it is essential to further refine the fabrication processes of each layer in the module,develop stable inorganic transport materials,and precisely control material formation and processing at the microscale and nanoscale to enhance charge transport.
