动态像面法测量水面落点位置及误差分析

为了测量弹丸水面落点的位置, 建立了基于CCD相机动态像面的测量模型。该模型通过CCD相机辅助采集相关点位的图像信息, 对水面落点的位置函数以及误差进行了研究。首先, 利用空间几何获得靶船上三定点相对于测量船的方位、俯仰信息。接着, 结合t时刻观测图像上定点的像面坐标, 运用底片常数模型建立像面坐标和角度信息两套参量之间的关系函数, 从而得到目标落点的方位、俯仰信息, 再利用异面交会法计算出目标落点位置。最后, 分析了目标落点位置的误差来源(质心误差, 位置误差)、误差以及各误差源与位置坐标之间的关系。实验结果表明:在测量船位置精度达到0.05 m, 图像质心定位精度达到0.5 pixel时, 在最小交会误差的情况下, 目标落点的位置测量误差分别为2.8, 4.9, 4.3 m。     

Residential relocation dynamics: A microeconomic model based on agents’ socioeconomic change and learning

This article develops a mathematical model for residential location choice in which previous experience is considered via a dynamic learning process and each agent evaluates location decisions according to their utility. Agents’ idiosyncratic behavior is modeled, assuming a stochastic willingness to pay based on dwelling and neighborhood attributes and households’ socioeconomics. Additionally, the willingness to pay is affected by the agent’s experience of the urban context in previous periods. Numerical examples are given, and simulations are conducted using linear bid functions. Additionally, concepts of urban dynamics are used in the long-term, assuming quasi-equilibrium in the bids considering the externalities of urban configurations. The results are compared with a static outcome corresponding to the equilibrium model of land use. The comparison is performed using indices of urban segregation and both short- and long-term configurations. The studied dynamics show that static modeling does not explain all the features associated with such a configuration of the urban system (in both short and long term).     

The checkpoint ordering problem

We suggest a new variant of a row layout problem: Find an ordering of n departments with given lengths such that the total weighted sum of their distances to a given checkpoint is minimized. The Checkpoint Ordering Problem (COP) is both of theoretical and practical interest. It has several applications and is conceptually related to some well-studied combinatorial optimization problems, namely the Single-Row Facility Layout Problem, the Linear Ordering Problem and a variant of parallel machine scheduling. In this paper we study the complexity of the (COP) and its special cases. The general version of the (COP) with an arbitrary but fixed number of checkpoints is NP-hard in the weak sense. We propose both a dynamic programming algorithm and an integer linear programming approach for the (COP) . Our computational experiments indicate that the (COP) is hard to solve in practice. While the run time of the dynamic programming algorithm strongly depends on the length of the departments, the integer linear programming approach is able to solve instances with up to 25 departments to optimality.     

光化学反应-串联质谱法鉴定细胞中不饱和卵磷脂双键的位置

以二苯甲酮(Benzophenone,BP)为光化学反应的反应物,建立了乳腺细胞中不饱和卵磷脂双键位置和双键异构体相对含量的在线光化学反应-脉冲直流电喷雾串联质谱(PB-pulsed-dc-ESI-MS/MS)的检测方法.通过三相萃取法提取细胞中的脂类,在254 nm紫外光的照射下,使不饱和卵磷脂中的C詤C和BP中的羰基发生特异性的环加成反应(Paternó-Bǜchi,PB反应),将反应后的PB产物通过非接触式的脉冲直流电喷雾(Pulsed directed current electrospray,pulsed-dc-ESI)方式电离,并进行低能碰撞裂解得到二级串联质谱(MS/MS),从得到的二级谱图的子离子中可以获得双键位置以及双键异构体相对含量的信息.检测了癌细胞MCF-7和正常细胞MCF-10A中8种不饱和卵磷脂中的双键位置,且对其中4种双键异构体的相对含量进行分析,发现PC 16:018:1中△9异构体的含量在两种细胞中差异不明显,PC 18:018:1和PC 18:118:1中△9异构体的含量略有差异,LPC 18:1中△9异构体的含量在癌细胞和正常两种细胞中差异比较明显(56.0%±1.3%vs.71.7%±6.8%).本方法快速简易,可用于分析双键位置及双键异构体相对含量,有望对不同细胞状态以及不同疾病状态进行鉴别.     

Round‐robin test for the measurement of layer thickness of multilayer films by secondary ion mass spectrometry depth profiling

An international round‐robin test (RRT) was performed to investigate a method to determine the interface location and the layer thickness of multilayer films by secondary ion mass spectrometry (SIMS) depth profiling as a preliminary study to develop a new work item proposal in ISO/TC‐201. Two types of reference materials were used in this RRT. A SiGe alloy (Si_52.4Ge_47.6) reference film was used to determine the relative sensitivity factors of Si and Ge. A Si/Ge multilayer reference film was used to determine the relative sputtering rates of the Si and Ge layers. The layer thicknesses were measured from the interfaces determined by a 50 atomic percent definition. Seven laboratories from 5 countries participated in this international RRT. The RRT reference expanded uncertainties for Si and Ge layers in a Si/Ge multilayer with similar thicknesses as the reference film were 0.76 and 1.17 nm, respectively. However, those in a thinner Si/Ge multilayer film were slightly larger at 1.04 and 1.59 nm, respectively. Most of the thickness ratios in the 2 Si/Ge multilayer films were consistent with the RRT reference value within their expanded uncertainties.     

Correlation of precursor and product ions in single-stage high resolution mass spectrometry. A tool for detecting diagnostic ions and improving the precursor elemental composition elucidation

Monitoring of common diagnostic fragments is essential for recognizing molecules which are members of a particular compound class. Up to now, unit resolving tandem quadrupole mass spectrometers, operating in the precursor ion scan mode, have been typically used to perform such analysis. By means of high-resolution mass spectrometry (HRMS) a much more sensitive and selective detection can be achieved. However, using a single-stage HRMS instrument, there is no unequivocal link to the corresponding precursor ion, since such instrumentation does not permit a previous precursor selection. Thus, to address this limitation, an in silico approach to locate precursor ions, based on diagnostic fragments, was developed. Implemented as an Excel macro, the algorithm rapidly assembles and surveys exact mass data to provide a list of feasible precursor candidates according to the correlation of the chromatographic peak shape profile and other additional filtering criteria (e.g. neutral losses and isotopes). The macro was tested with two families of veterinary drugs, sulfonamides and penicillins, which are known to yield diagnostic product ions when fragmented. Data sets obtained from different food matrices (fish and liver), both at high and low concentration of the target compounds, were investigated in order to evaluate the capabilities and limitations of the reported approach. Finally, other possible applications of this technique, such as the elucidation of elemental compositions based on product ions and corresponding neutral losses, were also presented and discussed.     

Location of courts of justice: The making of the new judiciary map of Portugal

Location modeling techniques have been applied to an extremely wide variety of public facilities. However, their application to one of the most ubiquitous public facilities – courts of justice – has been very rare. In this paper, we describe a study promoted by the Ministry of Justice of Portugal to define a proposal for the country's new judiciary map – that is, the spatial organization of the judicial system. The new map aims to promote the efficiency and specialization of the justice system (leading to better and faster court decisions) and to provide a good level of accessibility to courts. We developed two optimization models addressing those goals – a districting model, to determine the borders of new, large judicial districts; and a court location model, to determine the location, type, size, and coverage area of the courts included in each new district. Both models are discrete facility location models and consider hierarchical facilities – generic courts and specialized courts of multiple types. Our study was publicly acknowledged by the Portuguese government as having contributed to the new judiciary map that has since been approved and implemented.     

一类多商品设施选址问题的基于线性松弛解的启发式方法

多商品设施选址问题是众多设施选址问题中一类重要而困难的问题.在这一问题中,顾客的需求可能包含不止一种商品.对于大规模问题,成熟的商业求解器往往不能在满意的时间内找到高质量的可行解.研究了无容量限制的单货源多商品设施选址问题的一般形式,并给出了应用于此类问题的两个启发式方法.这两个方法基于原选址问题的线性规划松弛问题的最优解,分别通过求解紧问题和邻域搜索的方式给出了原问题的一个可行上界.理论分析指出所提方法可以实施于任意可行问题的实例.数值结果表明所提方法可以显著地提高求解器求解此类设施选址问题的求解效率.     

考虑居民选择行为的应急避难场所选址问题研究

突发事件发生后,应急管理部门将面临选择启用哪些应急避难场所供居民避难的决策。与其它设施选址不同,处于有限理性状态下的居民可选择是否去避难以及去哪个避难所避难。为使未被服务的居民数量最小化,考虑居民的有限理性选择行为至关重要。为此,考虑居民避难距离及避难所吸引力等因素,基于竞争选址理论构建避难所对居民的效用函数。在此基础上,运用多项logit模型刻画居民的有限理性选择行为,建立基于有限理性选择行为的选址模型,并与基于效用最优选择行为和基于系统最优原则的选址模型进行对比以验证模型的合理性。为了高效地求解模型,设计了模拟退火算法和遗传算法两种启发式算法。算例分析结果验证了模型和算法的可行性和有效性,并揭示了居民理性程度、选址个数及财政预算均对选址结果有重要影响。     

需求导向的容量设施竞争选址问题研究

客户意愿与容量限制是竞争设施选址问题中两个重要的影响因素,在考虑客户意愿与设施容量共同作用条件下,建立了最小化企业总成本以及每个客户费用为目标的竞争设施选址问题优化模型,通过设计需求导向服务分配机制解决设施与客户之间服务关系分配问题,结合模拟退火思想提出了求解模型的算法。最后利用数值例子分析了需求导向服务分配机制以及目标权重、预算限额等参数对于选址决策的影响,其中考虑需求导向因素会适当增加企业的总成本,但可以减少客户所付出的费用从而增强对客户的吸引力;另外企业的预算限额对于企业的设施选址决策有着重要的影响,企业所能获取的市场份额与其选址预算限额呈正相关的关系;而客户所需付出的总费用与企业提供服务的总成本两者之间则呈负相关的关系,因此需要通过服务质量与成本之间的权衡实现最理想的选址决策。