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A refined risk explicit interval linear programming approach for optimal watershed load reduction with objective-constraint uncertainty tradeoff analysis

Pingjian YANG,Feifei DONG,Yong LIU,Rui ZOU,Xing CHEN,Huaicheng GUO

《环境科学与工程前沿（英文）》 2016年 第10卷 第1期   页码 129-140 doi: 10.1007/s11783-014-0683-8

摘要： To enhance the effectiveness of watershed load reduction decision making, the Risk Explicit Interval Linear Programming (REILP) approach was developed in previous studies to address decision risks and system returns. However, REILP lacks the capability to analyze the tradeoff between risks in the objective function and constraints. Therefore, a refined REILP model is proposed in this study to further enhance the decision support capability of the REILP approach for optimal watershed load reduction. By introducing a tradeoff factor ( ) into the total risk function, the refined REILP can lead to different compromises between risks associated with the objective functions and the constraints. The proposed model was illustrated using a case study that deals with uncertainty-based optimal load reduction decision making for Lake Qionghai Watershed, China. A risk tradeoff curve with different values of was presented to decision makers as a more flexible platform to support decision formulation. The results of the standard and refined REILP model were compared under 11 aspiration levels. The results demonstrate that, by applying the refined REILP, it is possible to obtain solutions that preserve the same constraint risk as that in the standard REILP but with lower objective risk, which can provide more effective guidance for decision makers.

关键词： refined risk explicit interval linear programming     decision making     objective-constraint uncertainty tradeoff     aspiration level     Lake Qionghai Watershed    

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Comparison of CT-guided aspiration to key hole craniotomy in the surgical treatment of spontaneous putaminal

ZHAO Jizong, WANG Dejiang, WANG Shuo, YUAN Ge, KANG Shuai, JI Nan, ZHAO Yuanli, YE Xun, ZHOU Liangfu, ZHOU Dingbiao, WANG Renzhi, WANG Mei

《医学前沿（英文）》 2007年 第1卷 第2期   页码 142-146 doi: 10.1007/s11684-007-0027-1

摘要： This study was designed to compare the approaches and efficacies of two different ways of neurosurgical management for spontaneous putaminal hemorrhage (SPH): computed tomographic-guided aspiration (CTGA) and the key-hole approach (KHA). The indications of the two approaches are also explored. From September 2001 to 2003, a total of 1077 cases of SPH distributed in 135 hospitals all over the mainland of China were included for analysis. All cases had three-month follow-up data. The study was designed in a single-blinded manner to compare the efficacies of the different approaches. There were 563 cases in the CTGA group, 165 in the KHA group, and 217 cases in the conventional open craniotomy (COC) group. In the CTGA and KHA groups, the mortalities at one month after operation (M1m) were 17.9% and 18.3%, respectively, while the mortalities at three months after operation (M3m) were 19.4% and 19.4%, respectively (>0.05). The postoperative complications due to CTGA (23.7%) were not significantly different from those due to KHA (25.7%) ( = 0.420). The M3m of patients with Glasgow coma scale (GCS) "d8 was 3.45 and 4.0 times as much as those with GCS>8, respectively. The M3m of patients with complications was 3.92 times as much as those without complications. The M3m of patients with hemorrhage volume "e70 mL was 2.67 times as much as those <70 mL. The CTGA is not better than KHA in the treatment of SPH in terms of a more favorable outcome or less mor tality and morbidity, but CTGA could be the first choice for those with bleeding volumes "d50mL, while KHA is the first choice for those with bleeding volumes >50 mL.

关键词： tomographic-guided aspiration     single-blinded manner     favorable outcome     operation     Glasgow    

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Simulation of heterogeneous two-phase media using random fields and level sets

George STEFANOU

《结构与土木工程前沿（英文）》 2015年 第9卷 第2期   页码 114-120 doi: 10.1007/s11709-014-0267-5

摘要： The accurate and efficient simulation of random heterogeneous media is important in the framework of modeling and design of complex materials across multiple length scales. It is usually assumed that the morphology of a random microstructure can be described as a non-Gaussian random field that is completely defined by its multivariate distribution. A particular kind of non-Gaussian random fields with great practical importance is that of translation fields resulting from a simple memory-less transformation of an underlying Gaussian field with known second-order statistics. This paper provides a critical examination of existing random field models of heterogeneous two-phase media with emphasis on level-cut random fields which are a special case of translation fields. The case of random level sets, often used to represent the geometry of physical systems, is also examined. Two numerical examples are provided to illustrate the basic features of the different approaches.

关键词： microstructure     random fields     level sets     shape recovery     two-phase media    

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Insult of gastroesophageal reflux on airway: clinical significance of pharyngeal nozzle

null

《医学前沿（英文）》 2015年 第9卷 第1期   页码 117-122 doi: 10.1007/s11684-014-0343-1

摘要：

At the very time of global paying the highest attention to the worst insults of smoking as well as haze on the airway, everybody knows both are exogenous and noticeable. However, people mostly, including many medical personnel, do not know how badly the gastroesophageal reflux (GER) insults on our own airway. Symptoms of GER are commonly seen as heartburn and regurgitation, which can be mostly tolerated. However, when the up going gastric content reversely passes the esophagus and then the distal pharynx, where it appears a beak like stricture, serving as a nozzle, so as to produce numerous micro-particles and reach the oro-nasal cavity and also the airway causing allergic rhinitis and asthmatic attacks, even pulmonary parenchyma lesions. It will reduce life quality or even jeopardize life. The point that the endogenous insult appears in the respiratory system, but originates from the digestive tract is not well known and often undiagnosed and not correctly treated. The GER induced airway challenge is a treatable and preventive entity, as soon as a diagnosis is made, a good relief could be expected by means of life style adjustment, medicine, or fixation of the patulous cardia through radiofrequency or fundoplication. The author Dr. Zhonggao Wang had suffered it for long and symptoms disappeared for 8 years after anti-reflux surgery. Here is a presentation of Dr. Zhonggao Wang and his team’s work and would call attention to the public so as to recognize this relatively unknown entity — a treatable condition occurring from human itself, but not from outside surroundings as smoking or haze does.

关键词： gastroesophageal reflux     airway     pharyngeal nozzle     micro-aspiration     asthma    

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The effect of sea level rise on beach morphology of caspian sea coast

M. A. Lashteh NESHAEI, F. GHANBARPOUR

《结构与土木工程前沿（英文）》 2017年 第11卷 第4期   页码 369-379 doi: 10.1007/s11709-017-0398-6

摘要： Study of beach morphology has been one of the most important issues in coastal engineering research projects. Because of the existence of two important coastal areas located in the north and south parts of the Iran, in the present study an analysis of the coastal zone behaviour is made. Bed level elevations are measured and compared with the theoretical equilibrium profile. It is shown that the behaviour of the coastal zone in the region is consistent with the Dean (1991) equilibrium profile. In the next stage, following extensive investigations, the bed level changes due to arise in sea level at different locations in the surf zone are estimated. The mechanism of beach re-treatment due to a rise in sea level is considered based on the simplified model of Dean (1991) in which the mass balance of the sediments is taken into account. Comparison of the equilibrium profiles for different cases of sea level rise, clearly shows that because of the sediment transport induced by the fluctuation of the water level, the beach profile in the surf zone changes accordingly resulting in an erosion in the inner region of the surf zone and an accumulation of sediments towards the offshore.

关键词： wave     coastal zone     beach morphology     evolution     equilibrium profile     sea level rise    

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Level set band method: A combination of density-based and level set methods for the topology optimization

Peng WEI, Wenwen WANG, Yang YANG, Michael Yu WANG

《机械工程前沿（英文）》 2020年 第15卷 第3期   页码 390-405 doi: 10.1007/s11465-020-0588-0

摘要： The level set method (LSM), which is transplanted from the computer graphics field, has been successfully introduced into the structural topology optimization field for about two decades, but it still has not been widely applied to practical engineering problems as density-based methods do. One of the reasons is that it acts as a boundary evolution algorithm, which is not as flexible as density-based methods at controlling topology changes. In this study, a level set band method is proposed to overcome this drawback in handling topology changes in the level set framework. This scheme is proposed to improve the continuity of objective and constraint functions by incorporating one parameter, namely, level set band, to seamlessly combine LSM and density-based method to utilize their advantages. The proposed method demonstrates a flexible topology change by applying a certain size of the level set band and can converge to a clear boundary representation methodology. The method is easy to implement for improving existing LSMs and does not require the introduction of penalization or filtering factors that are prone to numerical issues. Several 2D and 3D numerical examples of compliance minimization problems are studied to illustrate the effects of the proposed method.

关键词： level set method     topology optimization     density-based method     level set band    

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钢塔节段水平预拼装关键技术研究

张永利,顾碧峰

《中国工程科学》 2010年 第12卷 第4期   页码 48-52

摘要：

通过对泰州长江公路大桥钢塔柱预拼装方案的选择和关键工艺的研究，提出结构形式复杂的钢塔节段预拼装工艺选择原则。在研究了钢塔节段预拼环境的影响、支撑条件、金属接触率等水平预拼装关键工艺控制项点后，成功地解决了泰州桥钢塔节段水平预拼装中的技术难题。钢塔节段水平预拼装填补了我国钢塔制造的技术空白，为后续复杂钢塔节段水平预拼装方案选择提供了有力基础。

关键词： 钢塔     水平预拼装     支撑控制     水平力施加    

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Two-level uncapacitated lot-sizing problem considering the financing cost of working capital requirement

Yuan BIAN, David LEMOINE, Thomas G. YEUNG, Nathalie BOSTEL

《工程管理前沿（英文）》 2020年 第7卷 第2期   页码 248-258 doi: 10.1007/s42524-019-0069-5

摘要： During financial crisis, companies constantly need free cash flows to efficiently react to any uncertainty, thus ensuring solvency. Working capital requirement (WCR) has been recognized as a key factor for releasing tied up cash in companies. However, in literatures related to lot-sizing problem, WCR has only been studied in the single-level supply chain context. In this paper, we initially adopt WCR model for a multi-level case. A two-level (supplier–customer) model is established on the basis of the classic multi-level lot-sizing model integrated with WCR financing cost. To tackle this problem, we propose sequential and centralized approaches to solve the two-level case with a serial chain structure. The ZIO (Zero Inventory Ordering) property is further confirmed valid in both cases. This property allows us to establish a dynamic programming-based algorithm, which solves the problem in O(T ). Finally, numerical tests show differences in optimal plans obtained by both approaches and the influence of varying delays in payment on the WCR of both actors.

关键词： two-level ULS problem     lot-sizing     working capital requirement     ZIO property     infinite production capacity    

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Understanding the demand predictability of bike share systems: A station-level analysis

《工程管理前沿（英文）》   页码 551-565 doi: 10.1007/s42524-023-0279-8

摘要： Predicting demand for bike share systems (BSSs) is critical for both the management of an existing BSS and the planning for a new BSS. While researchers have mainly focused on improving prediction accuracy and analysing demand-influencing factors, there are few studies examining the inherent randomness of stations’ observed demands and to what degree the demands at individual stations are predictable. Using Divvy bike-share one-year data from Chicago, USA, we measured demand entropy and quantified the station-level predictability. Additionally, to verify that these predictability measures could represent the performance of prediction models, we implemented two commonly used demand prediction models to compare the empirical prediction accuracy with the calculated entropy and predictability. Furthermore, we explored how city- and system-specific temporally-constant features would impact entropy and predictability to inform estimating these measures when historical demand data are unavailable. Our results show that entropy of demands across stations is polarized as some stations exhibit high uncertainty (a low entropy of 0.65) and others have almost no check-out demand uncertainty (a high entropy of around 1.0). We also validated that the entropy and predictability are a priori model-free indicators for prediction error, given a sequence of bike usage demands. Lastly, we identified that key factors contributing to station-level entropy and predictability include per capita income, spatial eccentricity, and the number of parking lots near the station. Findings from this study provide more fundamental understanding of BSS demand prediction, which can help decision makers and system operators anticipate diverse station-level prediction errors from their prediction models both for existing stations and for new ones.

关键词： bike share systems     demand prediction     prediction errors     machine learning     entropy    

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Conceptual design of compliant mechanisms using level set method

Shi-kui CHEN, Michael Yu WANG

《机械工程前沿（英文）》 2006年 第1卷 第2期   页码 131-145 doi: 10.1007/s11465-006-0018-y

摘要： We propose a level set method-based framework for the conceptual design of compliant mechanisms. In this method, the compliant mechanism design problem is recast as an infinite dimensional optimization problem, where the design variable is the geometric shape of the compliant mechanism and the goal is to find a suitable shape in the admissible design space so that the objective functional can reach a minimum. The geometric shape of the compliant mechanism is represented as the zero level set of a one-higher dimensional level set function, and the dynamic variations of the shape are governed by the Hamilton-Jacobi partial differential equation. The application of level set methods endows the optimization process with the particular quality that topological changes of the boundary, such as merging or splitting, can be handled in a natural fashion. By making a connection between the velocity field in the Hamilton-Jacobi partial differential equation with the shape gradient of the objective functional, we go further to transform the optimization problem into that of finding a steady-state solution of the partial differential equation. Besides the above-mentioned methodological issues, some numerical examples together with prototypes are presented to validate the performance of the method.

关键词： splitting     minimum     dimensional optimization     Hamilton-Jacobi     topological    

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System engineering for water pollution control at the watershed level in China

Wei MENG,

《环境科学与工程前沿（英文）》 2009年 第3卷 第4期   页码 443-452 doi: 10.1007/s11783-009-0037-0

摘要： The present water pollution situation at watershed level in China has been systematically analyzed. The causes of water pollution are attributed to the extensive economic developmental pattern, poor wastewater treatment, and a lack of nonpoint pollution control. The problems of water pollution control at watershed level include a lack of thought and approach, developmental delay in the environmental standard system, an inadequate monitoring ability, and an inefficient implementation of laws and regulations. From 2006 to 2020, water pollution control and governance will be a national key specific project of science and technology in China. The strategies of this project include establishing a water pollution control system at watershed level, orienting a healthy aquatic ecosystem, conducting risk management, and using comprehensive methods. The goal is to establish and complete a technological system of pollution control and management in three five-year phases. The main tasks are to develop common technologies, management systems, and mechanisms for lake eutrophication control, river pollution control, urban water environmental pollution control, potable water safety, and water environmental management. The bottlenecks of water pollution control and management in China could be systematically removed, and the demonstration of the system engineering approach will be conducted at selected key watersheds.

关键词： water pollution control     watershed     system engineering     sustainability     integrated watershed management     key specific project of science and technology    

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Analysis of inventory level under procurement constraints in supply chain

CHANG Guangshu

《机械工程前沿（英文）》 2007年 第2卷 第3期   页码 361-363 doi: 10.1007/s11465-007-0063-1

摘要： Because the inventory is one of the major factors that affect the performance of the supply chain system, efficient reduction of an inventory can effectively reduce the cost level of the total supply chain. Therefore, inventory management is an important means to optimize the operation of a supply chain and enhance the competitive advantage. Considering the (, ) policy in an inventory management, this paper establishes a model of the inventory level. Then, the change of the inventory level with and without the procurement constraints is analyzed, and their expectation and variance calculated. Consequently, the order point can be determined accurately to reduce the inventory level and the operation risk.

关键词： supply     efficient reduction     system     expectation     procurement    

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Effect of fly ash replacement level on the fracture behavior of concrete

Mahdi AREZOUMANDI, Jeffery S. VOLZ

《结构与土木工程前沿（英文）》 2013年 第7卷 第4期   页码 411-418 doi: 10.1007/s11709-013-0228-4

摘要： The production of portland cement–the key ingredient in concrete–generates a significant amount of carbon dioxide. However, due to its incredible versatility, availability, and relatively low cost, concrete is the most consumed manmade material on the planet. One method of reducing concrete’s contribution to greenhouse gas emissions is the use of fly ash to replace a significant amount of the cement. ?This study presents the results of an experimental investigation that evaluates effect of fly ash replacement level on the fracture energy of concrete. This study includes four mixes with 0%, 30%, 50%, and 70% fly ash as a cement replacement. This experimental program consisted of 32 fracture beams to study the fracture behavior of concrete. The experimental fracture energies were compared with the fracture energy provisions of different design codes and also different analytical equations. Furthermore, statistical data analyses (parametric and non-parametric) were performed to evaluate whether or not there is any statistically significant difference between the experimental fracture energies of different mixes. Results of these statistical tests show that the mix with higher level of fly ash replacement level has higher fracture energy.

关键词： concrete     fracture energy     fly ash    

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New insights into the formation of ammonium nitrate from a physical and chemical level perspective

《环境科学与工程前沿（英文）》 2023年 第17卷 第11期 doi: 10.1007/s11783-023-1737-6

摘要：

● Factor analysis of ammonium nitrate formation based on thermodynamic theory.

关键词： Ammonium nitrate formation     Thermodynamic theory     Aerosol liquid water content     Source apportionment    

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Water-level based discrete integrated dynamic control to regulate the flow for sewer-WWTP operation

Zhengsheng Lu, Moran Wang, Mingkai Zhang, Ji Li, Ying Xu, Hanchang Shi, Yanchen Liu, Xia Huang

《环境科学与工程前沿（英文）》 2020年 第14卷 第3期 doi: 10.1007/s11783-020-1222-4

摘要： A model-free sewer-WWTP integrated control was proposed. A dynamic discrete control based on the water level was developed. The approach could improve the sewer operation against flow fluctuation. The approach could increase transport capacity and enhance pump efficiency. This study aims to propose a multi-point integrated real-time control method based on discrete dynamic water level variations, which can be realized only based on the programmable logic controller (PLC) system without using a complex mathematical model. A discretized water level control model was developed to conduct the real-time control based on data-automation. It combines the upstream pumping stations and the downstream influent pumping systems of wastewater treatment plant (WWTP). The discretized water level control method can regulate dynamic wastewater pumping flow of pumps following the dynamic water level variation in the sewer system. This control method has been successfully applied in practical integrated operations of sewer-WWTP following the sensitive flow disturbances of the sewer system. The operational results showed that the control method could provide a more stabilized regulate pumping flow for treatment process; it can also reduce the occurrence risk of combined sewer overflow (CSO) during heavy rainfall events by increasing transport capacity of pumping station and influent flow in WWTP, which takes full advantage of storage space in the sewer system.

关键词： Sewer system     Integrated control     Discrete control     Water level    

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标题 作者 时间 类型 操作

A refined risk explicit interval linear programming approach for optimal watershed load reduction with objective-constraint uncertainty tradeoff analysis

Pingjian YANG,Feifei DONG,Yong LIU,Rui ZOU,Xing CHEN,Huaicheng GUO

期刊论文

Comparison of CT-guided aspiration to key hole craniotomy in the surgical treatment of spontaneous putaminal

ZHAO Jizong, WANG Dejiang, WANG Shuo, YUAN Ge, KANG Shuai, JI Nan, ZHAO Yuanli, YE Xun, ZHOU Liangfu, ZHOU Dingbiao, WANG Renzhi, WANG Mei

期刊论文

Simulation of heterogeneous two-phase media using random fields and level sets

George STEFANOU

期刊论文

Insult of gastroesophageal reflux on airway: clinical significance of pharyngeal nozzle

null

期刊论文

The effect of sea level rise on beach morphology of caspian sea coast

M. A. Lashteh NESHAEI, F. GHANBARPOUR

期刊论文

Level set band method: A combination of density-based and level set methods for the topology optimization

Peng WEI, Wenwen WANG, Yang YANG, Michael Yu WANG

期刊论文

钢塔节段水平预拼装关键技术研究

张永利,顾碧峰

期刊论文

Two-level uncapacitated lot-sizing problem considering the financing cost of working capital requirement

Yuan BIAN, David LEMOINE, Thomas G. YEUNG, Nathalie BOSTEL

期刊论文

Understanding the demand predictability of bike share systems: A station-level analysis

期刊论文

Conceptual design of compliant mechanisms using level set method

Shi-kui CHEN, Michael Yu WANG

期刊论文

System engineering for water pollution control at the watershed level in China

Wei MENG,

期刊论文

Analysis of inventory level under procurement constraints in supply chain

CHANG Guangshu

期刊论文

Effect of fly ash replacement level on the fracture behavior of concrete

Mahdi AREZOUMANDI, Jeffery S. VOLZ

期刊论文

New insights into the formation of ammonium nitrate from a physical and chemical level perspective

期刊论文

Water-level based discrete integrated dynamic control to regulate the flow for sewer-WWTP operation

Zhengsheng Lu, Moran Wang, Mingkai Zhang, Ji Li, Ying Xu, Hanchang Shi, Yanchen Liu, Xia Huang

期刊论文