一线救治伤员后送资源配置策略研究

参考国内外历史案例和数据,构建战场伤员产生的仿真模型。基于该模型,利用综合评价、资源配置优化算法,研究探讨连抢救组及营救护站的救治、后送运力配置及路径规划策略。利用假设战例验证模型,基于减员预计模型计算减员情况,分析了相应的营、连救治策略。结果验证一线伤员收拢后送运力配置及路径优化模型可靠,可为一线救治信息化、自动化、智能化发展提供技术支撑。本研究为一线伤员救治、收拢、后送力量配置及路径规划提供理论方法。     

A multi-objective combinatorial model of casualty processing in major incident response

During the emergency response to mass casualty incidents decisions relating to the extrication, treatment and transporting of casualties are made in a real-time, sequential manner. In this paper we describe a novel combinatorial optimization model of this problem which acknowledges its temporal nature by employing a scheduling approach. The model is of a multi-objective nature, utilizing a lexicographic view to combine objectives in a manner which capitalizes on their natural ordering of priority. The model includes pertinent details regarding the stochastic nature of casualty health, the spatial nature of multi-site emergencies and the dynamic capacity of hospitals. A Variable Neighborhood Descent metaheuristic is employed in order to solve the model. The model is evaluated over a range of potential problems, with results confirming its effective and robust nature.     

Applying simulation optimization to the asset allocation of a property–casualty insurer

Proper asset allocations are vital for property–casualty insurers to be competitive and solvent. Theories of finance offer little practical guidance in constructing such asset allocations however. This research integrates simulation models with a newly developed evolutionary algorithm for the multi-period asset allocation problem of a property–casualty insurer. We first construct a simulation model to simulate operations of a property–casualty insurer. Then we develop multi-phase evolution strategies (MPES) to be used with the simulation model to search for promising asset allocations for the insurer. A thorough experiment is conducted to evaluate the performance of our simulation optimization approach. Computational results show that MPES is an effective search algorithm. It dominates the grid search method by a significant margin. The re-allocation strategy resulting from MPES outperforms re-balancing strategies significantly. This research further demonstrates that the simulation optimization approach can be used to study economic issues related to multi-period asset allocation problems in practical settings.     

Safety cameras and road accidents: effectiveness in local authority areas in England

Safety cameras have been central to strategy for improving road safety in the UK (and other countries) over the past decade and a National Safety Camera (NSC) programme was introduced in the year 2000 to fund and guide the expansion of camera sites. This programme was brought to an end in 2007 and responsibility for decisions on expanding, maintaining or rolling back safety cameras has now been largely devolved to local highway authorities and their partners. To make strategic choices in such areas it is clearly vital to understand the extent to which safety cameras are effective in reducing road accident potential. Although the NSC programme has been evaluated this work has focussed mainly on assessments of impacts at camera sites rather than wider area effects: particularly local highway area effects. The research reported here has explored the rates of personal injury collisions (PIC) over the past decade on the roads of English Local Authority areas and investigated relationships between area characteristics including levels of safety camera introductions and the PIC improvements (or otherwise) reported. To assist in this analysis, an indicator of safety camera intensity has been derived in this research to reflect the relative likelihood in areas of coming into contact with safety camera sites This work shows that area improvement rates differ significantly on an urban/rural dimension and are also very dependent on prior (to camera introductions) levels of PIC risk. Controlling for these factors using a pair comparison approach, analysis shows that safety camera introduction effects are statistically detectable in very highly urbanised, high PIC risk areas and at high risk sites within areas but not elsewhere. Whilst recognising that new high risk sites can emerge in any area, the conclusion is reached that many local areas and especially more rural areas would be unlikely to gain advantage from a further general expansion of fixed point and mobile camera sites and that de-commissioning of current sites should be seriously considered.     

An Asset Liability Management Model for Casualty Insurers: Complexity Reduction vs. Parameterized Decision Rules

In this paper we study possibilities for complexity reductions in large scale stochastic programming problems with specific reference to the asset liability management (ALM) problem for casualty insurers. We describe a dynamic, stochastic portfolio selection model, within which the casualty insurer maximizes a concave objective function, indicating that the company perceives itself as risk averse. In this context we examine the sensitivity of the solution to the quality and accuracy with which economic uncertainties are represented in the model. We demonstrate a solution method that combines two solution approaches: A truly stochastic, dynamic solution method that requires scenario aggregation, and a solution method based on ex ante decision rules, that allow for a greater number of scenarios. This dynamic/fix mix decision policy, which facilitates a huge number of outcomes, is then compared to a fully dynamic decision policy, requiring fewer outcomes. We present results from solving the model. Basically we find that the insurance company is likely to prefer accurate representation of uncertainties. In order to accomplish this, it will accept to calculate its current portfolio using parameterized decision rules.     

Connected autonomous vehicles: State of practice

Connected autonomous vehicles (CAVs) have the potential to deal with the steady increase in road traffic while solving transportation related issues such as traffic congestion, pollution, and road safety. Therefore, CAVs are becoming increasingly popular and viewed as the next generation transportation solution. Although modular advancements have been achieved in the development of CAVs, these efforts are not fully integrated to operationalize CAVs in realistic driving scenarios. This paper surveys a wide range of efforts reported in the literature about the CAV developments, summarizes the CAV impacts from a statistical perspective, explores current state of practice in the field of CAVs in terms of autonomy technologies, communication backbone, and computation needs. Furthermore, this paper provides general guidance on how transportation infrastructures need to be prepared in order to effectively operationalize CAVs. The paper also identifies challenges that need to be addressed in near future for effective and reliable adoption of CAVs.     

基于离散与连续选址相结合的平面选址问题研究——以华北石油局大牛地气田污水处理厂选址为例

选址问题的研究中,大多考虑的是理论距离(例如欧式距离等);但在实际问题中,真实的公路运输距离和理论距离有较大差异,并且修建公路的成本较高.在尽量利用当前的公路交通网络同时,又能得到最优选址,在现实中具有重要意义.以华北石油局大牛地气田第一采气厂污水处理厂选址为例,分别采用重心法选址、最大值最小化选址、多目标选址等选址的方法得到污水处理厂的备选点,并结合实际距离模拟出了各个备选点的运输费用,再综合考虑当地政策和交通状况等因素,最终得到了使得运输费用最低的新的污水处理厂的位置坐标P(9.33,11.79),在该位置建立污水处理厂比之前的运输方案每年大约可节约511万元的运输费用.方法最大的优点是减小了在选址过程中理论距离与实际距离的误差,在现实中具有一定的指导意义.     

Models and algorithms to improve earthwork operations in road design using mixed integer linear programming

In road construction, earthwork operations account for about 25% of the construction costs. Existing linear programming models for earthwork optimization are designed to minimize the hauling costs and to balance the earth across the construction site. However, these models do not consider the removal of physical blocks that may influence the earthwork process. As such, current models may result in inaccurate estimates of optimal earthwork costs, leading to poor choices in road design. In this research, we extend the classical linear program model of earthwork operations to a mixed integer linear program model that accounts for blocks. We examine the economic impact of incorporating blocks via mixed integer linear programming, and find significant savings for most road designs in our test-set. However, the resulting model is considerably harder to solve than the original linear program. Based on structural observations, we introduce a set of algorithms that theoretically reduce the solving time of the model. We confirm this reduction in solve time with numerical experiments.     

Multilayers in a modulated stochastic game

We are concerned with an antagonistic stochastic game between two players A and B which finds applications in economics and warfare. The actions of the players are manifested by a series of strikes of random magnitudes at random times exerted by each player against his opponent. Each of the assaults inflicts a random damage to enemy's vital areas. In contrast with traditional games, in our setting, each player can endure multiple strikes before perishing. Predicting the ruin time (exit) of player A, along with the total amount of casualties to both players at the exit is a main objective of this work. In contrast to the time sensitive analysis (earlier developed to refine the information on the game) we insert auxiliary control levels, which both players will cross in due game before the ruin of A. This gives A (and also B) an additional opportunity to reevaluate his strategy and change the course of the game. We formalize such a game and also allow the real time information about the game to be randomly delayed. The delayed exit time, cumulative casualties to both players, and prior crossings are all obtained in a closed-form joint functional.     

基于模糊理论的交通安全评价方法的研究

道路交通安全系统的内部结构极为复杂,影响因素众多,各因素都具有模糊性.在综合研究分析国内外道路交通安全评价方法的基础上,对以往发生的道路交通事故资料进行分析,利用模糊评价理论,选取合理评价指标,建立了基于模糊的道路交通安全评价模型,对道路交通的安全性进行合理评价.     

Design decisions in interactive geometry software

Software design is increasingly being recognized as an important factor in student learning when interacting with interactive geometry software (IGS). A categorization of the operations possible within an IGS is used to identify and analyse design decisions made in a number of current IGS programs: Cabri II Plus, Cabri 3D, Cinderella, GeoGebra and Geometer’s Sketchpad. The analysis, in the context of exploring the area of a circle, is focused on construction, dragging, and alternative spatial and semantic views. A wide diversity of both design issues and individual design decisions was identified, illustrating both the scarcity of research in this area and a number of inevitable tensions, such as between functionality and complexity, and between static and dynamic geometry, related to which future research questions might be posed.     

Evaluation of a new maintenance concept for the preservation of highways

Asphalt roads gradually deteriorate over time and need mendingto remain in a good state. Inspections are performed to obtaininformation about the current state of the road; when the levelof damage reaches the established standards, the road is repairedthrough a maintenance action that is considered most cost-effective.Because of economies of scale, it is to a certain extent economicalto limit the number of maintenance services by integrating neighbouringsegments into a homogeneous section which is completely repaired.In this report we consider the question of whether it is economicallyjustified to adopt a maintenance concept in which the road isoccasionally regenerated from junction to junction with a distanceof several kilometers. The big advantage of junction-to-junctionmaintenance is that it can be done within special road barrierconstructions which reduce the road capacity only slightly,so that the road can be maintained 24 hours a day.     

Emergency response in natural disaster management: Allocation and scheduling of rescue units

Natural disasters, such as earthquakes, tsunamis and hurricanes, cause tremendous harm each year. In order to reduce casualties and economic losses during the response phase, rescue units must be allocated and scheduled efficiently. As this problem is one of the key issues in emergency response and has been addressed only rarely in literature, this paper develops a corresponding decision support model that minimizes the sum of completion times of incidents weighted by their severity. The presented problem is a generalization of the parallel-machine scheduling problem with unrelated machines, non-batch sequence-dependent setup times and a weighted sum of completion times – thus, it is NP-hard. Using literature on scheduling and routing, we propose and computationally compare several heuristics, including a Monte Carlo-based heuristic, the joint application of 8 construction heuristics and 5 improvement heuristics, and GRASP metaheuristics. Our results show that problem instances (with up to 40 incidents and 40 rescue units) can be solved in less than a second, with results being at most 10.9% up to 33.9% higher than optimal values. Compared to current best practice solutions, the overall harm can be reduced by up to 81.8%.     

Metaheuristic approaches to the placement of suicide bomber detectors

Suicide bombing is an infamous form of terrorism that is becoming increasingly prevalent in the current era of global terror warfare. We consider the case of targeted attacks of this kind, and the use of detectors distributed over the area under threat as a protective countermeasure. Such detectors are non-fully reliable, and must be strategically placed in order to maximize the chances of detecting the attack, hence minimizing the expected number of casualties. To this end, different metaheuristic approaches based on local search and on population-based search (such as a hill climber, different Greedy randomized adaptive search procedures, an evolutionary algorithm and several estimation of distribution algorithms) are considered and benchmarked against a powerful greedy heuristic from the literature. We conduct an extensive empirical evaluation on synthetic instances featuring very diverse properties. Most metaheuristics outperform the greedy algorithm, and a hill-climber is shown to be superior to remaining approaches. This hill-climber is subsequently subject to a sensitivity analysis to determine which problem features make it stand above the greedy approach, and is finally deployed on a number of problem instances built after realistic scenarios, corroborating the good performance of the heuristic.     

Insuring against loss of evidence in game-theoretic probability

Statistical testing can be framed as a repetitive game between two players, Forecaster and Sceptic. In each round, Forecaster sets prices for various gambles, and Sceptic chooses which gambles to make. If Sceptic multiplies by a large factor the capital he puts at risk, he has evidence against Forecaster’s ability. His capital at the end of each round is a measure of his evidence against Forecaster so far. This can go up and then back down. If you report the maximum so far instead of the current value, you are exaggerating the evidence against Forecaster. In this article, we show how to remove the exaggeration. Removing it means systematically reducing the maximum in such a way that a rival to Sceptic can always play so as to obtain current evidence as good as Sceptic’s reduced maximum. We characterize the functions that can achieve such reductions. Because these functions may impose only modest reductions, we think of our result as a method of insuring against loss of evidence. In the context of an actual market, it is a method of insuring against the loss of what an investor has gained so far.     

Developing geographical indicators of mileage-related costs: a case study exploring travelling public services in English local areas

The context of this study is the public sector provision of services involving travelling in local authority areas in England. Such travelling services are costly and the relative levels of these costs across different local areas have raised a number of policy issues, particularly how performance assessments of local authorities and capitation-based funding by central government take into account (or fail to take into account) the differential travel costs faced in geographical areas that differ in population dispersion (sparsity) characteristics. The research presented here is concerned with identifying and evaluating practical indicators of mileage-related costs faced in local areas and a range of indicators have been explored for three services: domiciliary care, refuse collection and home-to-school transport. The findings suggest that currently used population dispersion indicators could be improved and that the current sparsity allowances in England underestimate the relative cost effects by a considerable amount.     

Research,Reform, and Equity in U.S. Mathematics Education

This article discusses mathematics education research in relation to equity and current U.S. reforms. Although mathematics education researchers and reformers give attention to equity, work in this area tends to ignore relevant social and cultural issues. I begin by surveying articles on equity published in recent, mainstream education journals, highlighting the lack of attention given to social class and ethnicity. I discuss the implications of this limited research base. Specifically, I argue that current mathematics education reforms have been shaped by good intentions and existing research, neither of which offers adequate guidance to address the complexities of equity in mathematics classrooms today. Drawing from a study of social class differences in students' experiences in one reform-oriented classroom, I discuss the challenges and dilemmas inherent in sociocultural approaches to research in mathematics education and their potential contributions. I call for research from a sociocultural perspective, focusing on ways in which students from underrepresented groups can struggle when encountering particular instructional approaches, and ways in which teachers and students are able to address such struggles.     

Integrating technology into mathematics teaching at the university level

The emergence of new computing technologies in the second half of the twentieth century brought about new potentials and promised the rapid transformation of the teaching and learning of mathematics. However, despite the vast investments in technology resources for schools and universities, the realities of schooling and the complexities of technology-equipped environments resulted in a much slower integration process than was predicted in the 1980s. Hence researchers, together with teachers and mathematicians, began examining and reflecting on various aspects of technology-assisted teaching and learning and on the causes of slow technology integration. Studies highlighted that as technology becomes increasingly available in schools, teachers’ beliefs and conceptions about technology use in teaching are key factors for understanding the slowness of technology integration. In this paper, I outline the shift of research focus from learning and technology environment-related issues to teachers’ beliefs and conceptions. In addition, I highlight that over the past two decades a considerable imbalance has developed in favour of school-level research against university-level research. However, several changes in universities, such as students declining mathematical preparedness and demands from other sciences and employers, necessitate closer attention to university-level research. Thus, I outline some results of my study that aimed to reflect on the paucity of research and examined the current extend of technology use, particularly Computer Algebra Systems (CAS) at universities, mathematicians’ views about the role of CAS in tertiary mathematics teaching, and the factors influencing technology integration. I argue that due to mathematicians’ extensive use of CAS in their research and teaching, documenting their teaching practices and carrying out research at this level would not only be beneficial at the university level but also contribute to our understanding of technology integration at all levels.     

Research, Reform, and Equity in U.S. Mathematics Education

This article discusses mathematics education research in relation to equity and current U.S. reforms. Although mathematics education researchers and reformers give attention to equity, work in this area tends to ignore relevant social and cultural issues. I begin by surveying articles on equity published in recent, mainstream education journals, highlighting the lack of attention given to social class and ethnicity. I discuss the implications of this limited research base. Specifically, I argue that current mathematics education reforms have been shaped by good intentions and existing research, neither of which offers adequate guidance to address the complexities of equity in mathematics classrooms today. Drawing from a study of social class differences in students' experiences in one reform-oriented classroom, I discuss the challenges and dilemmas inherent in sociocultural approaches to research in mathematics education and their potential contributions. I call for research from a sociocultural perspective, focusing on ways in which students from underrepresented groups can struggle when encountering particular instructional approaches, and ways in which teachers and students are able to address such struggles.