An Approach to Urban Traffic State Estimation by Fusing Multisource Information

This paper presents an information-fusion-based approach to the estimation of urban traffic states. The approach can fuse online data from underground loop detectors and global positioning system (GPS)-equipped probe vehicles to more accurately and completely obtain traffic state estimation than using either of them alone. In this approach, three parts of the algorithms are developed for fusion computing and the data processing of loop detectors and GPS probe vehicles. First, a fusion algorithm, which integrates the federated Kalman filter and evidence theory (ET), is proposed to prepare a robust, credible, and extensible fusion platform for the fusion of multisensor data. After that, a novel algorithm based on the traffic wave theory is employed to estimate the link mean speed using single-loop detectors buried at the end of links. With the GPS data, a series of technologies are combined with the geographic information systems for transportation (GIS-T) map to compute another link mean speed. These two speeds are taken as the inputs of the proposed fusion platform. Finally, tests on the accuracy, conflict resistance, robustness, and operation speed by real-world traffic data illustrate that the proposed approach can well be used in urban traffic applications on a large scale.     

基于STM8S103和WIFI的智能家居照明系统设计

人们对生活体验的要求越来越高,Android智能手机带给人们更快捷舒适的操作,WIFI无线信息传输技术日趋成熟。将WIFI无线传输方式用到智能家居照明系统,由Android智能手机终端进行控制成为一种发展趋势。STM8S103单片机作为核心控制器,由WIFI无线方式进行信息传输,结合手机终端控制程序,实现智能家居照明系统的设计。能轻松的利用Android手机对室内灯源进行开关、调光等控制,具有很好的应用和体验效果。     

Construction of ubiquitous acoustic spaces using audio watermark technology and mobile terminals

We propose ‘Ubiquitous Acoustic Spaces,’ where each sound source can emit some address information and automatically enable us to access its related cyber space, using mobile terminals. This will be used for a new type of wireless advertisement for mobile phones using sound media. In order to realize this, we have proposed a nearly lossless audio watermarking technique, utilizing two‐channel stereo audio characteristics. This enables contactless asynchronous detection of embedded watermarks through loudspeaker and microphone devices even by using cell phones. We extend the embedding frequency band width and improve the extraction precision. Thus we enable watermark extraction from both stereo channels. Possible embedding data rate can be extended to 80 bps, and almost 100% data can be extracted in case of using PC or PDA devices as terminals. Moreover, we can carry out the watermark extraction even from cell phone loudspeakers or through public telephone networks. From our experiments, almost 100% extraction of 20 bps embedded data could be achieved with these phone devices. In this paper, we describe briefly our newly proposed dual monaural watermark embedding algorithms, and present a prototype system of ubiquitous acoustic spaces using cell phones, based on our experimental results of extraction precision on several capture signal conditions including experiments using cell phones or public telephone networks. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Real-time freeway level of service using inductive-signature-based vehicle reidentification system

The Highway Capacity Manual provides a method for determining the level of service (LOS) on freeways to evaluate freeway performance. Apart from being essentially an off-line decision support tool for planning and design, it is also based on point measurements from loop detectors, which may not provide an accurate assessment of freeway section performance. In order to meet user requirements of advanced traffic management and information systems, new LOS criteria based on section measures are required for real-time freeway analysis. The main aim of this research was to demonstrate a technique for development of such LOS criteria. The study uses a new measure of effectiveness, called reidentified median section speed (RMSS), derived from analysis of inductive vehicle signatures and reidentification of vehicles traveling through a major section of freeway in the City of Irvine, CA. Two main issues regarding real-time LOS criteria were addressed. The first was how to determine the threshold values partitioning the LOS categories. To provide reliable real-time traffic information, the threshold values should be decided such that RMSSs within the same LOS category represent similar traffic conditions as much as possible. In addition, RMSSs in different LOS categories should represent dissimilar traffic conditions. The second issue concerned the aggregation interval to use for deriving LOS categories. Two clustering techniques were then employed to derive LOS categories, namely, k-means and fuzzy approaches. Wilk's Lambda analysis and LOS stability analysis were performed to design new LOS criteria. Six LOS categories defined in terms of RMSS over a fixed 240-s interval were identified as the best solution to meet two major considerations described above. The procedures used in this study are readily transferable to other similarly equipped freeway sections for the derivation of real-time LOS.     

Mobile Phones: Bad for Your Health?

Mobile phones use electromagnetic fields to establish a wireless communication link to the nearest base station. When someone speaks on a mobile phone, that phone is sending out electromagnetic waves (EM). When someone listens on a mobile phone, that phone is capturing electromagnetic waves. Electromagnetic waves go out and come into a mobile phone through its antenna. That antenna is located very close to the user's head, and people have naturally wondered about the health effects of radiation from mobile phones since their inception.     

Using ITS to Improve the Capacity of Freeway Merging Sections by Transferring Freight Vehicles

This paper investigates the effect of heavy commercial vehicles on traffic characteristics and operation of freeway merging sections. Freeways are designed to facilitate the flow of traffic, including passenger cars and trucks. The impact of these different vehicle types is not uniform, creating problems in freeway operations and safety, particularly in the vicinity of merging sections. There have been very few studies that are concerned with the traffic behavior and characteristics of heavy vehicles in these situations. Therefore, a three-year study was undertaken to investigate traffic behavior and operating characteristics during the merging process under congested traffic conditions. First extensive traffic data collection captured a wide range of traffic and geometric information using detectors, videotaping, and surveys at several interchanges. The macroscopic detector data were used to identify and quantify the impact of heavy commercial vehicles on the capacity of merging sections. Subsequently, the microscopic data were utilized to establish a model for the behavior of drivers at merging sections. Based on this behavioral model, a microsimulation program was developed to simulate the actual traffic conditions. This model was used to evaluate the capacity of a merging section for a given geometric design and traffic flow condition. In addition, this model was employed to develop a variety of intelligent transport system control strategies that are associated with heavy commercial vehicles with the goal of designing safer and less-congested freeway merging points. The implementation of the proposed control strategies showed significant improvement over the capacity of merging sections.      

Mobile communications - an overview

This article focuses on voice communications using mobile (cell) phones over mobile/cellular networks. The advances in processors, memory, signal processing, communication technologies, and several related techniques, personal mobile communications has witnessed tremendous growth. A typical mobile communication network consists of: mobile devices, BS, mobile switching centers, gateway mobile switching center. Cell phones communicate wirelessly with BSs. Base stations communicate with MSCs on fiber-optic cables or microwave links. Some of the extensions are also made in the cell phone, MMS, JPEG format, MPEG format, graphics, and animation.     

Control of Freeway Traffic Flow in Unstable Phase by $H_{infty}$ Theory

This paper devises a freeway controller that is capable of stabilizing traffic flow when the traffic system is in the unstable (congested) phase, in which a shock wave is likely to occur in the presence of any inhomogeneity and where the system is on the verge of a jam condition. Two types of traffic controllers are developed through the use of either a speed command approach that can be implemented in an intelligent transportation system (ITS) or ramp metering that is a typical way of preventing a freeway from overloading. By means of the feedback linearization technique, the discretized macroscopic traffic flow model is reformulated, in which the desired change of volume in each section is treated as a virtual input. By exploring the casual relations among density, speed, and flow change, the corresponding speed commands can be determined. The traffic flow control problem is formulated as an H_infin control design problem so that uncertainties that are associated with the macroscopic model can be taken into account. Simulations show that the devised controller can effectively stabilize the traffic flow in the unstable phase. Design flexibilities associated with the method are also discussed.     

Alien Revolt (2005-2007): A Case Study of the First Location-Based Mobile Game in Brazil

Location-aware technology and Internet connectivity embedded in mobile phones allow users to navigate physical spaces and be connected to other users, bringing many activities formerly performed "online" to physical hybrid spaces. Among such activities are location-based mobile games (LBMGs), which use urban spaces as the game scenario. This article is a case study of Alien Revolt (2005-2007), the first Brazilian LBMG, released in 2005 by the company Mind Corporation and the operator Oi in Rio de Janeiro. The game uses Java-enabled cell phones equipped with location awareness to transform the city into a battlefield. Following much of the Swedish game Botfighters' (2001-2005) idea, the first LBMG, Alien Revolt's goal involves virtually shooting other players within a specific radius in the city space. Alien Revolt exemplifies how cell phones strengthen users' connections to physical space, because they are used as collective communication devices, rather than personal private technologies. Moreover, when used for location-based activities, the cell phone plays the role of a location aware technology, rather than a mobile telephone used for two-way voice communication.     

基于改进的SSD模型手机违规使用目标检测

针对某些对手机使用有特殊规定的场所时常面临难以准确、高效地识别手机违规使用的问题,提出了一种基于改进的SSD模型来检测手机的违规使用。利用SSD模型获取初次目标位置及区域分类,并利用改进的DenseNet模型对初次目标框进行判定,从而获得精确的手机检测边界框。为改进数据预处理流程,采用了数据扩增与图像质量改善相结合的策略。在自建的手机检测数据集上的实验结果验证了这些改进策略的有效性,改进的SSD模型定位精度可达91.1%,识别精度高达98%,相比原有SSD模型提升了35%。改进的SSD模型同时具有识别精度高和定位精度高的特点,可为智能识别违规使用手机的行为提供理论依据和技术支持。     

基于SPCE061A与GPRS的变电站物联网智能安防系统设计

针对变电站内可能出现的火灾、SF6泄露、入站盗抢等情况,设计了一种基于SPCE061A单片机,通过通用无线分组业务(GPRS)发送手机短信完成变电站警报的物联网智能安防系统。该安防系统主要由3部分组成,主控单元(凌阳单片机SPCE061A)、采集(温度、烟雾、门磁传感器)单元和无线GPRS(MC35)网络报警单元。SPCE061A是主控部分,并利用温度、烟雾、门磁等传感器采集信息,内置A/D完成数据采集,并支配MC35完成无线传输,把险情以手机短消息的形式及时发送报警信息到多个人,实现手机多点自动互联。实验结果表明,该系统响应速度灵敏、警报无时延、可靠性高、布线简单,且价格低廉,应用前景广泛,不仅可以用在变电站,还可以用在居民楼、商场、仓库等一系列场合中。     

交互式手机定制与展示系统

以手机为例,研制开发了产品定制和展示系统。介绍了手机设计定制系统的用户界面与组件构成;提出了交互式定制系统的工作流程与定制实例;阐述并示例了手机虚拟展示环境,包括虚拟人模型及其结构、人体动作的设计技术。     

A CTI System to Support the Seamless Workplace and Its Implementation

This paper proposes a CTI client/server coordination system exclusively for use with a smart phone. The system makes use of a CTI client, performing combined functions of a SIP phone and a Web browser. The proposed CTI client/server coordination system comprises SIP servers and Web servers, both of which are installed in enterprises, and CTI clients that run on smart phones in a mobile environment. Furthermore, the CTI clients perform the function of SIP phone by communicating with SIP servers. In addition, CTI clients can display telephone directories and logging of phone calls stored in Web servers. They can display screens of ordinary Web browsers. Here, one might switch between a SIP phone function and a Web communication screen with merely a single touch of the tab key. Consequently, smart phones in the mobile environment make it possible to conduct telephone meetings while browsing with a Web screen.     

A simple and effective method for predicting travel times on freeways

We present a method to predict the time that will be needed to traverse a given section of a freeway when the departure is at a given time in the future. The prediction is done on the basis of the current traffic situation in combination with historical data. We argue that, for our purposes, the current traffic situation of a section of a freeway is well summarized by the current status travel time. This is the travel time that would result if one were to depart immediately and no significant changes in traffic would occur. This current status travel time can be estimated from single- or double-loop detectors, video data, probe vehicles, or any other means. Our prediction method arises from the empirical observation that there exists a linear relationship between any future travel time and the current status travel time. The slope and intercept of this relationship may change subject to the time of day and the time until departure, but linearity persists. This observation leads to a prediction scheme by means of linear regression with time-varying coefficients.     

Optimal coordination of variable speed limits to suppress shock waves

When freeway traffic is dense, shock waves may appear. These shock waves result in longer travel times and in sudden large variations in the speeds of the vehicles, which could lead to unsafe situations. Dynamic speed limits can be used to eliminate or at least to reduce the effects of shock waves. However, coordination of the variable speed limits is necessary in order to prevent the occurrence of new shock waves and/or a negative impact on the traffic flows in other locations. In this paper, we present a model predictive control approach to optimally coordinate variable speed limits for freeway traffic with the aim of suppressing shock waves. First, we optimize continuous valued speed limits, such that the total travel time is minimal. Next, we include a safety constraint that prevents drivers from encountering speed limit drops larger than, e.g., 10 km/h. Furthermore, to get a better correspondence between the computed and applied control signals, we also consider discrete speed limits. We illustrate our approach with a benchmark problem.     

拍照手机在低照度时成像分辨率的测试方法研究

分析了手机拍摄静止图像的影响因素,阐述了利用ISO 12233分辨率图表测试手机低照度成像分辨率的方法。对市场上常见的两款手机进行了测试,分别用显示图像评估法和软件测试空间频率响应法给出了计算公式、检测数据及结果,比较了两种数据分析方式的优缺点并给出结论。     

Development of a mobile spreadsheet-based PID control simulation system

The use of the electronic spreadsheet as a modeling and simulation tool in the engineering fields is increasingly popular with an increasing number of tertiary institutions, including spreadsheet as a teaching resource in the core curriculum of these fields. Concurrently, the dramatic improvement in Internet speed allows certain course material to be delivered online, facilitating electronic-learning (E-learning). E-learning frees students from the restriction of time, although they are still largely constrained by space to the nearest wired computer. However, the boundary of computing has expanded with the advance in wireless communication; now numerous handheld mobile devices (e.g., personal digital assistants (PDAs) and cellular phones) are available that will allow computing to be accomplished on the move. In turn, this wireless trend has contributed to move E-learning toward mobile learning (M-learning). Based on the previously mentioned trends, this paper presents the development, implementation, and evaluation of a mobile spreadsheet-based Proportional, Integral, Derivative (PID) control simulation system that aims to enhance the learning of the student in the field of control engineering. The system has been used in an industrial control system course at the National University of Singapore (NUS), Singapore. The mobile spreadsheet system developed is able to work with most handheld mobile devices, including the cellular phone. The methods and difficulties (e.g., limited storage space and small screen display of a cellular phone) involved in the development of the system will be duly discussed. Feedback from students that is used to assess the usefulness of the system will be released to share the benefits of such an M-learning system.     

Smart phones and interactive reports leave traffic in the rearview mirror

To convey the dynamic information related to traffic conditions in various parts of a city, we propose an environment utilizing the technology of smart phones to provide information anywhere and anytime. Called ";The Interactive Traffic Beat Project,"; it uses a Web-based service to deliver this information to people through their cell phones at the right time so that valuable time can be saved and the chaos on the roads can be managed.     

考虑坡度工况的FCHEV队列分层优化控制策略研究

在面对坡度工况时，如何开发同时兼顾车辆间协同控制与能耗经济性的控制策略是提高交通效率与发挥车辆节能潜力的关键技术之一。以燃料电池混合动力汽车队列为研究对象，以安全行驶及优化能耗为目标，提出了一种基于改进粒子群优化算法与Q学习的燃料电池混合动力汽车队列分层优化控制策略。该策略中上层控制器在保证满足与前车距离或速度限制等安全约束的前提下，利用改进的粒子群优化算法获取节能速度轨迹，并使用模型预测控制框架实时调整主车速度遵循节能速度轨迹行驶。下层控制器根据上层求解的车速和需求功率等信息建立Q学习控制器，实现燃料电池混合动力汽车动力电池与燃料电池之间的最优能量分配。仿真结果表明，本文所提出的分层控制策略在坡度工况下，表现出良好的跟踪性能和安全性能，且优化结果与动态规划策略相似，表明该策略的能耗经济性及可行性。     

基于Kalman滤波器的车辆检测与跟踪系统的实现

智能交通系统是解决城市交通拥挤最有效的方式,其中交通信息采集设备是交通系统管理的基础与前提,而基于视频图像处理的交通信息检测器较其他类型检测器,具有信息量丰富,安装和维护成本低廉的特点.本文用基于Kalman滤波器的方法实现了交通信息采集设备中的车辆检测与跟踪.它采用了一种自适应背景更新算法,通过分割、二值化、腐蚀膨胀得出前景图像,以包含前景图像的矩形框的中心作为Kalman滤波器的跟踪特征,对运动车辆进行跟踪估计得出车辆的运动轨迹和速度.一系列的视频实验表明,该方法简单可行而且对天气、光照变化、阴影有很强的适应能力.