基于改进引力搜索算法的室内定位锚节点部署方案

在室内定位场景中,锚节点的部署对定位性能具有重要影响.考虑存在障碍物的室内环境,基于缺少环境详细信息或者缺少设备模拟室内信号传播的基本场景,综合考虑可定位率、定位精度以及是否冗余部署的指标,设计一种新的评价函数,并利用改进的引力搜索算法(GSA)进行求解,在可接受时间成本内得到室内定位锚节点部署问题的较优解.仿真实验中将所提出算法与3种参考算法进行对比,在定位率、几何精度因子(GDOP)值、定位误差等方面所提出算法都表现出较优的性能;同时,针对考虑部分因素的评价函数进行比较,通过对多个指标项的分析,证实所提出的评价函数可以获得较优的锚节点部署方案,从而能够有效改善锚节点拓扑,提高定位性能.     

Positioning empty containers under dependent demand process

Owing to trade imbalance, shipping companies position empty containers between ports or depots periodically. The most difficult problem for positioning is that it is not possible to know the exact amounts of empty containers required in the future. The paper deals with the problem of positioning empty containers in a port area with multiple depots. Customer demands and returning containers in depots per unit time period are assumed to be serially-correlated and dependent random variables. Three options are considered to prepare the required extent of positioning: positioning from other overseas ports, inland positioning between depots, and leasing. The policies for empty-container management consist of three parts as follows: a coordinated, (s, S) inventory policy for positioning from other ports, (r_i, R_i) policy for inland positioning between depots; and a simple leasing policy with zero lead-time. For inland positioning policy, four heuristic methods are proposed to reposition empty containers between depots. The objective is to obtain optimal policies corresponding to different methods of inland positioning in order to minimize the expected total costs. A genetic-based optimization procedure is developed to find the optimal parameters (s, S) and (r_i, R_i). Some numerical examples and sensitivity analyses are given to demonstrate the results.     

Application of a mixed fuzzy decision making and optimization programming model to the empty container allocation

Containerization transportation has been growing fast in the past few decades. International trades have been growing fast since the globalization of world economies intensified in the early 1990s. However, these international trades are typically imbalanced in terms of the numbers of import and export containers. As a result, the relocation of empty containers has become one of the important problems faced by liner shipping companies. In this paper, we consider the empty container allocation problem where we need to determine the optimal volume of empty containers at a port and to reposition empty containers between ports to meet exporters’ demand over time. We formulate this empty container allocation problem as a two-stage model: in stage one, we propose a fuzzy backorder quantity inventory decision making model for determining the optimal quantity of empty container at a port; whereas in stage two, an optimization mathematical programming network model is proposed for determining the optimal number of empty containers to be allocated between ports. The parameters such as the cost of loading container, cost of unloading container, leasing cost of empty container, cost of storing container, supplies, demands and ship capacities for empty containers are considered in this model. By taking advantages of the fuzzy decision making and the network structure, we show how a mixed fuzzy decision making and optimization programming model can be applied to solve the empty container allocation problem. The utilization of the proposed model is demonstrated with a case of trans-Pacific liner route in the real world. Six major container ports on the trans-Pacific route are considered in the case study, including the Port of Kaohsiung, the Port of Hong Kong, the Port of Keelung, the Port of Kobe, the Port of Yokohama and the Port of Los Angles. The results show that the proposed mixed fuzzy decision making and optimization programming model can be used to solve the empty container allocation problem well.     

NR在60GHz定位过程的隐藏节点规避方法

60GHz非授权频段因其波长短、频段宽的无线传播特性可实现更高的定位信号测量精度,因此5G NR-U设备基于60GHz频段进行高精度定位倍受关注;但是由于5G网络是多网异构共存的,存在众多不同无线接入技术（RAT,radio access technology）的设备,潜在的隐藏节点多,即使5G NR-U设备采用先听后说（LBT,listen before talk）方式接入60GHz无线信道,仍无法有效规避隐藏节点,有时会严重干扰定位信号传输而影响定位性能;针对以上隐藏节点问题,文中提出对定位信号资源集中的多个定位信号资源分别配置不同的空间关系,接收端根据定位信号的测量结果实时动态调整其空间关系,尽可能多地规避潜在的隐藏节点;仿真验证结果表明所提方法可将定位信号的测量精度提升了约27%,显著降低定位误差。     

煤矿井下人员安全监测定位算法仿真研究

实时精确监测井下人员位置,对安全生产非常必要。井下环境复杂、坑道狭长,不同于室内,一段坑道不会采集到太多较好信号节点,无线信号传播时易受反射、多径传播和噪声等因素影响,致使传统Wi-Fi定位算法定位精度低,提出一种基于局部极大似然、信号强度来遴选Wi-Fi信号节点,并利用六点四四组合混合定位算法。首先信标节点周期性扫描移动定位模块,筛选出较优信号强度,并求出待求节点与信标节点间距离;然后局部极大似然六点四四组合;最后质心法求解中心,估计最终的井下人员位置。经过仿真验证：所提出的混合定位算法,定位精度明显提高。同时分析了井下不同噪声、基站情况下,几种定位算法性能,新算法定位精度仍然较高;最后还分析了算法的实时性。     

跨区域远洋航线空集装箱动态调运优化模型

由于海运业受世界经济不景气的影响,班轮企业竞争日益加剧。尽可能地降低营运成本是班轮企业生存和发展的关键因素。提出了跨区域远洋空集装箱动态调运优化模型（ECR-RDM）,该模型一方面针对传统模型（ECR-TM）基于港口间点到点空箱调运策略的缺陷,采用了基于港口集合到集合的空箱调运策略。另一方面,不同于传统模型解决空箱调运的静态分配特征,提出的模型可以根据实时需要动态分配空箱,一定程度上减少了由于调运计划和实际业务需求不同步性产生的各项成本。通过抽取实际业务中可能发生的六种情况,依次进行分析比较,验证了文中提出模型的有效性和可行性。同时,通过分析在可能的六种情况下租赁成本、存储成本、装卸成本在总调运成本中所占的比例,为班轮企业制定高效的运营策略提供决策依据。     

Development of the visible light communication device for swarm using nonlinear synchronization

This paper describes development of a visible light 4 Pulse position modulation (4PPM) data communication device for underwater swarms using a nonlinear synchronizing system. SWARM—a group robot that uses intelligence as a group—do as ants and bees, is expected to be useful for marine resource exploration. Specifically, numerous SWARMs will be grouped to explore marine resources efficiently. An important difficulty is the change in electronic circuit characteristics because of high water pressure in the deep sea. Development of small and simple underwater SWARM communication devices must eliminate this problem without using large pressure-proof containers. As described herein, we considered nonlinear synchronizing systems as effective because they can be synchronized even if system time constants differ. Such systems resemble the glow mechanism used by fireflies. They have individuality, but they flash synchronously when in a group. We developed a visible light communication device using this nonlinear synchronization system based on the firefly concept. Test results confirmed that they are synchronized even if a time constant difference exists between them. Furthermore, we achieved 4PPM data communication using the nonlinear synchronization signal as a communication clock.     

基于LTE方向型传播模型的模拟退火加权定位算法

针对LTE网络采集到的MRO数据,提出一种基于LTE方向型传播模型的模拟退火加权定位算法。先结合LTE定向天线和小区特性,引入方向型参量提出基于RSS的方向型传播模型,对传统的信号传播模型COST-231 Hata进行改进;然后提出距离比加权算法消除RSS波动误差,将定位问题转换为一元求解问题,使用模拟退火算法计算最优解;最后通过距离椭圆模型对结果进行方位校正,得到最终终端定位结果。算法对比实验结果表明,基于LTE方向型传播模型的模拟退火加权定位算法具有较高的定位精度,完全符合FCC规定的定位精度要求。     

Application of a combined fuzzy multiple criteria decision making and optimization programming model to the container transportation demand split

The container transportation demand split is one of the most important decision issues for government transportation departments and port organizations. In previous studies, many researchers assumed that the shipping carrier would aim to minimize the total operation cost by selecting an appropriate port as the most favorable one to call, and the shipper would aim to minimize the inland freight cost by selecting the nearest port as the most favorable one to import and export international trade containers. Thus, a number of mathematical programming models have been developed. But in practice, the shipping carrier not only aims to minimize the total operation cost but also takes into account other criteria such as the volume of containers and port facility conditions when choosing an appropriate port as the most favorable one to call. The shipper not only aims to minimize the inland freight cost but also takes into account the frequency of ship callings when choosing an appropriate port as the most favorable one to import and export international trade containers.Thus, the purpose of this paper is to formulate a combined fuzzy multiple criteria decision making and optimization programming model for solving the container transportation demand split problem. There are two stages in this combined model: in stage one, we first compute the container transportation demand split rate by using fuzzy multiple criteria decision making (MCDM) method; whereas in stage two, an optimization mathematical programming network model is proposed for determining the inland origin destination (O-D) of import/export containers. The utilization of the proposed model is demonstrated with a case of Taiwanese ports. The results show that the proposed combined fuzzy MCDM and optimization programming model can be used to explain the container transportation demand split practice.     

跳数加权DV-Hop定位算法

针对DV-Hop定位算法中距离估计误差对定位结果的影响,提出了一种信标节点优选方案和跳数加权DV-Hop定位算法。首先通过设定跳数阈值,保留跳数较少的信标节点,然后剔除近似在一条直线上的信标节点,完成信标节点优选,避免未知节点无法定位的情形。此外,利用Friis模型推导出距离估计误差与信号传播跳数之间的映射关系,采用传播跳数作为加权因子对定位结果进行了修正。仿真结果表明该算法降低了距离估计误差对定位精度的影响,提高了定位精度。     

基于虚拟参考标签的RFID定位系统构建方法

针对现有RFID定位系统在位置服务单一、部署大量RFID设备相互间产生信号干扰而影响定位精度等方面的不足,利用经典信号传播模型在定位区域内构造虚拟参考标签空间,进而构建了一种基于虚拟参考标签空间的移动对象定位方法。实际测试表明,本系统具有较高的定位精度,可以有效克服部署大量参考标签及定位读写器引起的设备干扰问题,定位精度在中心区域达到0.31m~1. 65m,在外围区域误差为1. 48m~3.72m。     

Sideloaders-a case study in the port industry

This report is an evaluation of a vehicle used in the port industry for handling containers. The vehicle is a self-loading lorry which both transports and stacks the containers within the port. Three aspects of the evaluation are discussed in the operating context: internal and external visibility, and the cab layouts. It is concluded that the vehicle has a restricted view to the rear, although with care this can be catered for. The design and position of the cab, however, can demand extreme and uncomfortable postures on the part of the driver. Certain anomalies in the cab control and display layouts are also briefly discussed, with a view to standardisation and a reduction of the driver's work-load. The main problem is seen as one of the integration of the driver/operator with a machine with two discrete functions. The visibility and posture problem areas are considered to stem from the compromises dictated by the nature of this dual-function vehicle. Imperial units are retained since containers are specified by the ISO on the basis of American measures.     

一种改进的基于KNN的动态预测指纹定位算法*

针对目前的WiFi室内定位普遍存在定位精度不高、定位结果不稳定等问题进行了研究,为了改善这些不稳定因素,根据室内传播信号波动较大的特点提出了一种基于KNN的指纹定位改进算法。该算法通过动态预测节点位置,从无线地图中过滤掉到标签处没有相似RSS向量的RP来寻找最近邻,以降低KNN算法的时间和计算复杂度。实验结果表明,改进后的算法在定位精确度方面有了较大的提高。因此,得出结论：改进后的KNN定位算法在减小位置漂移和定位的平均误差, 确实可以提高定位的精确度。     

基于改进Canny边缘检测的堆叠货箱分割定位方法

为了提高集装箱卸货的自动化水平,针对集装箱内堆叠货箱难分割定位的问题,提出了一种基于改进Canny边缘检测的堆叠货箱分割定位方法。通过阈值分割和形态学处理进行图像预处理,去除背景干扰,提取堆叠货箱区域图像,基于改进Canny算法对堆叠货箱进行边缘检测,根据堆叠货箱边缘特征进行筛选并基于最小二乘法进行直线拟合,解决边缘线条不连续和虚假边缘问题,对边缘进行区域化处理,以此将堆叠货箱分割成独立的货箱区域,提取每个独立货箱的最小外接矩形,得到货箱中心点的位置信息。实验结果表明,该方法对堆叠货箱有很好的分割效果,定位精度小于5 mm,满足定位精度要求。     

FM radio for indoor localization with spontaneous recalibration

The position of mobile users has become highly important information in pervasive computing environments. Indoor localization systems based on Wi–Fi signal strength fingerprinting techniques are widely used in office buildings with an existing Wi–Fi infrastructure. Our previous work has proposed a solution based on exploitation of a FM signal to deal with environments not covered with Wi–Fi signal or environments with only a single Wi–Fi access point. However, a general problem of indoor wireless positioning systems pertains to signal degradation due to the environmental factors affecting signal propagation. Therefore, in order to maintain a desirable level of localization accuracy, it becomes necessary to perform periodic calibrations of the system, which is either time consuming or requires dedicated equipment and expert knowledge. In this paper, we present a comparison of FM versus Wi–Fi positioning systems and a combination of both systems, exploiting their strengths for indoors positioning. We also address the problem of recalibration by introducing a novel concept of spontaneous recalibration and demonstrate it using the FM localization system. Finally, the results related to device orientation and localization accuracy are discussed.     

Hybrid greedy heuristics based on linear programming for the three‐dimensional single bin‐size bin packing problem

In this paper, we propose to solve the three‐dimensional single bin‐size bin packing problem (3D‐SBSBPP) using a simple strategy based on integer linear programming (ILP) heuristics, without using any improvement based on metaheuristics. We first propose an ILP that is converted into a series of three‐dimensional single knapsack problems (3D‐SKP). Then, the first tailored heuristic can be viewed as a hybrid approach in which both “selection” and “positioning” phases are combined. The first phase serves to select a subset of items where each of these items is susceptible to belonging to an active container. The positioning phase serves to pack a subset of items already preselected by the selection phase. Then, both phases cooperate till packing all items into their corresponding containers. The second heuristic can be viewed as an extended version of the first one. Indeed, before deciding whether the current container is closed or a new container is activated, “a local reoptimization phase” is considered. Finally, both proposed heuristics are evaluated on a set of random instances obtained by using the standard generator scheme of the literature. The provided results show that both proposed heuristics remain competitive when compared to the results obtained by one of the best methods of the literature.     

情境自适应的RSSI分段异构拟合定位方法

室内定位在公共安全、健康监护、定位服务等领域具有重要价值,提高定位精度和模型对环境的适应性已经成为室内定位的核心问题。其中通过接收信号强度指示RSSI值来获取距离是比较通用的方法。针对室内复杂环境中传统的对数距离损耗路径模型适用性不高的情况,提出了一种情境自适应的RSSI分段异构拟合定位方法。该方法利用信号在不同应用情境下传播损耗的差异性,将RSSI数据分为多个不同的拟合段,根据RSSI数据的区分特性寻找最优的分段拟合点,并为每个分段选择最优的拟合函数,使得分段数、分段位置和每个分段的拟合函数都适应相应的应用场景,从而实现高精度的RSSI信号拟合。实验结果表明,本文所提出的方法在RSSI拟合精度上均优于传统的单一拟合函数,可明显提高定位算法的精度。     

A simulation analysis for a transtainer-based container handling facility

The efficiency of a marine cargo terminal depends primarily upon a smooth and orderly flow of material during the container loading process. It has been observed that the transtainer operation is the bottleneck in the loading process due to the frequent container rehandles and its speed. Past attempts at improving port operations have concentrated on the computerization of the load planning function and the efficient warehouse of the outbound containers. These attempts have, to some extent, been successful but have not been able to significantly eliminate the unproductive movements of the material handling equipment during the load operation.This study proposes a methodology of utilizing a buffer space as a method to increase the utilization of the material handling equipment and reduce the total container loading time. A stimulation model using a graphics simulation system is developed to compare the proposed methodology with the current practice at the Port of Portland.The results from 96 simulation runs show that the use of a buffer space significantly improves the flow of material during the loading operation, resulting in an average of 4% reduction in the total loading time. The methodology proposed in this study can be evaluated and implemented for any transtainer-based container port operation, and is anticipated to make considerable contribution to the plannig of future container port design.     

基于无线信号K-M模型的三维室内定位算法研究

针对无线信号在室内环境中易受到干扰、波动较大等问题,提出一种改进粒子群优化RBF神经网络的无线信号K-M传播测距模型。利用RBF的非线性特性模拟室内传播的复杂性,以信号接入节点(AP)发射功率、路径损耗因子、未知节点(RP)接收信号强度值RSS等构建模型,预测输出AP与RP之间的距离d。以d为半径,AP为球心,建立多个球体方程,采用极大似然(MLE)采样方程组与RSS-d加权质心混合定位算法,粗略估算未知节点位置信息,再利用加权质心法来进一步提高RP的定位精度。通过MATLAB实验仿真表明,与常见的优化算法对比,该模型预测距离误差更小,平均距离误差为1.3 m;RP的三轴坐标平均误差分别为x轴1.55 m、y轴1.48 m、z轴0.98 m,表明该模型提高了定位精度。     

On the abstraction method for the container relocation problem

The container relocation problem or the blocks relocation problem is a classic combinatorial optimisation problem that occurs in day-to-day operations for facilities that use block stacking systems. A typical place where this problem arises is a container terminal where containers can be stacked vertically in order to utilise the scarce resource of yard surface, thus at times resulting in the unproductive reshuffling moves for containers stacked above the target container for retrieval. Due to the problem class being NP-hard, a number of studies on this topic propose heuristic approaches to solve this problem. There are a few exact methods (search-based algorithms or mathematical programming) proposed for this problem but the feasible problem size of such methods is quite restricted, limiting their practical significance. In this paper, we propose a new insight into reducing the search space of this problem by the abstraction method. Our main contribution to the existing literature is two-fold: the reduction in the search space by the abstraction method and the bidirectional search using the pattern database. Our computational results confirm that our approach enables instances of a near-practical size to be solved optimally within a reasonable computation time.