FAME--a flexible appearance modeling environment

Combined modeling of pixel intensities and shape has proven to be a very robust and widely applicable approach to interpret images. As such the active appearance model (AAM) framework has been applied to a wide variety of problems within medical image analysis. This paper summarizes AAM applications within medicine and describes a public domain implementation, namely the flexible appearance modeling environment (FAME). We give guidelines for the use of this research platform, and show that the optimization techniques used renders it applicable to interactive medical applications. To increase performance and make models generalize better, we apply parallel analysis to obtain automatic and objective model truncation. Further, two different AAM training methods are compared along with a reference case study carried out on cross-sectional short-axis cardiac magnetic resonance images and face images. Source code and annotated data sets needed to reproduce the results are put in the public domain for further investigation.     

ACO-based routing and spectrum allocation in flexible bandwidth networks

Optical networks with flexible bandwidth provisioning are a very promising networking architecture. It enables efficient resource utilization and supports heterogeneous bandwidth demands. In this paper, we focus on the dynamic routing and spectrum allocation (RSA) problem which emerges in such networks and propose a novel dynamic RSA algorithm by means of ant colony optimization (ACO). In our proposed algorithm, ants are launched to modify the routing table according to the length and the spectrum fragmentation information along the path. A simulation study is performed considering five algorithms in terms of blocking probability: WDM-based RWA approach, KSP-based RSA approach, Slot-based RSA algorithm, and our proposed ACO-based RSA approach. We then compare the deterioration degree of blocking probability by adding more types of line rate. Simulation results indicate that our proposed ACO-based RSA approach achieves lower blocking probability, complexity, and higher adaptability to more line rates mixture.     

面向城市环境的角度矢量分簇选择协议

在车载自组织网VANETs(vehicular ad hoc networks)中,高动态的拓扑结构和频繁断裂的链路给车间通信提出挑战。为此,针对VANETs城市场景,提出基于方向矢量角簇群和桥节点的车间通信VAC-BNR(Vector-angle-cluster and bridge nodes-based routing)协议。VAC-BNR协议将城市道路划分为十字路口区域和十字路口间的直线路段区域。在十字路口区域内,选择合适的车辆作为桥节点,并由桥节点连通断裂的链路。而在直线路段区域,利用矢量角将车辆划分不同的簇群,然后计算每个簇群内节点的效用值,并选择效用值最高的车辆传输数据。仿真结果表明,提出的VAC-BNR协议能够有效地降低端到端传输时延、提高数据包传递率。与AMD相比,VAC-BNR协议的平均端到端传输时延下降了约30%,当车流密度大于80辆/km~2时,数据包传递率提高了约50%。     

Distance-adaptive routing and spectrum assignment in OFDM-based flexible transparent optical networks

Orthogonal frequency division multiplexing (OFDM) technology has been recently gaining increasing attention in flexible optical networks due to its significant spectrum efficiency, flexibility, and superior tolerance against impairments. In this paper, we put forward a novel distance-adaptive routing and spectrum assignment algorithm to select the proper modulation format dynamically based on OFDM according to the transmission reach, thereby effectively improving the spectrum utilization. The presented simulation results show that our proposed algorithm achieves significantly improved spectrum efficiency.     

针对有限TCAM的SDN网络灵活局部路由故障恢复

在软件定义网络中,使用大量的备份路径的转发规则会频繁地在交换机上进行数据流驱动,会增加带宽需求和处理延迟。对此,开发一组问题优化模型,可最小化备份路径所需的额外规则和带宽数量。由于该问题的计算复杂性,设计两个启发式算法计算备份路径:前向局部路由(FLR)和后向局部路由(BLR),从而提高TCAM和带宽的使用效率,并基于网络状态采用FLR和BLR设计了灵活自适应故障恢复框架。最后,通过在Internet 2网络拓扑上的仿真实验,显示所提算法在故障数据的抑制上要优于选取的对比算法,验证了算法性能优势。     

Study on dynamic routing and spectrum assignment in bitrate flexible optical networks

The exponential growth of Internet traffic necessitates high-capacity optical networks and has also highlighted the importance of bandwidth-flexible and multi-granularity transport platforms. Improving both transport capacity and bandwidth flexibility is a significant challenge in optical networks. A bitrate flexible network architecture that is based on orthogonal frequency division multiplexing has been proposed as a promising solution for meeting this challenge. In the current study, we focus on the online routing and spectrum assignment problems in the aforementioned network architecture and introduce a general solution for dynamic bitrate flexible traffic in distributed environments. A novel spectrum representation method based on continuous spectrum segments is introduced into the networks. Segment-based routing and signaling mechanisms provide general solutions that support both the conventional slot-based networks and the ideal fully gridless networks. The routing algorithms and spectrum selection approaches are demonstrated and compared in a simulation. Performance estimation indicates that random spectrum segment assignment achieves the lowest capacity blocking rate in light traffic, whereas the adaptive routing plus minimum residual spectrum scheme obtains the lowest capacity blocking rate under heavy traffic.     

The CMOS gate forest: an efficient and flexible high-performanceASIC design environment

The basic concepts of the second-generation gate arrays are described. The most important architectures that were used to implement the different concepts are discussed. An overview of the current status of a number of typical sea-of-gates masters is given. A number of quality marks have been defined along which the different architectures can be evaluated. These quality marks range from microarchitecture aspects such as isolation techniques and connectability of the core cells, to macro aspects such as distribution functions. Using these quality marks for reference, the Gate Forest is discussed. The Gate Forest is seen as a major extension of the sea-of-gates principle. It differs from the extant sea-of-gates concept in several important aspects. It is based on a hierarchical concept, both in architecture and design. It combines flexibility and efficiency in one environment by providing transistor-level optimization together with cell library support for different logic design styles. It furthermore supports the efficient implementation of different types of memory in any desired location. The current status of the second generation of the Gate Forest is also briefly described     

Conditions for worm-robot locomotion in a flexible environment: theory and experiments

Biological vessels are characterized by their substantial compliance and low friction that present a major challenge for crawling robots for minimally invasive medical procedures. Quite a number of studies considered the design and construction of crawling robots; however, very few focused on the interaction between the robots and the flexible environment. In a previous study, we derived the analytical efficiency of worm locomotion as a function of the number of cells, friction coefficients, normal forces, and local (contact) tangential compliance. In this paper, we introduce the structural effects of environment compliance, generalize our previous analysis to include dynamic and static coefficients of friction, determine the conditions of locomotion as function of the external resisting forces, and experimentally validate our previous and newly obtained theoretical results. Our experimental setup consists of worm robot prototypes, flexible interfaces with known compliance and a Vicon motion capture system to measure the robot positioning. Separate experiments were conducted to measure the tangential compliance of the contact interface that is required for computing the analytical efficiency. The validation experiments were performed for both types of compliant conditions, local and structural, and the results are shown to be in clear match with the theoretical predictions. Specifically, the convergence of the tangential deflections to an arithmetic series and the partial and overall loss of locomotion verify the theoretical predictions.     

Location update and routing scheme for a mobile computing environment

We present a new hierarchical location update and routing scheme for a wide area mobile computing environment with scalability of network hierarchy. Our scheme provides nearly optimal routing for most communication bypassing the mobile host's home network and home agent. We use simulation to compare our scheme with other schemes in both non‐hierarchical and hierarchical network architectures. Copyright © 2000 John Wiley & Sons, Ltd.     

An analytical paradigm to compare routing strategies in an ATMmultimedia environment

We propose an analytical model for the study of two different routing strategies in an ATM network supporting multimedia traffic flow: the multimedia virtual circuit (MVC) and the independent virtual circuit (IVC). The first strategy consists of assigning a single virtual channel to all of the monomedia streams which make up the multimedia flows; the second strategy consists of multiplexing homogeneous monomedia streams belonging to different multimedia sources on the same virtual channel. With this aim, a multimedia source is modeled as an arrival process defined as the superposition of heterogeneous correlated arrival processes, each of which models one monomedia source. In order to take into account the intermedia relationships which exist in a multimedia stream, each monomedia source is modeled as an interrupted Bernoulli process in which the transition and the arrival probabilities are functions of the states of the other monomedia sources. A finite-buffer discrete-time approach is used in order to compare MVC and IVC performance when an aggregate of N heterogeneous multimedia sources loads the network. Performance is evaluated for each monomedia source in terms of loss probability and jitter probability density function. To assess the proposed paradigm, a case study is shown     

云计算环境下通信网络路由协调控制器设计

传统路由协调控制器设计方法存在数据传输次数少、传输不准确等问题,无法将节点分配均衡,大大降低了网络控制效率。为此,提出基于云计算环境下通信网络路由协调控制器的设计。构建协调控制器模块框图,利用低压差分技术设计光纤以太网协调控制器结构;设计云计算环境下控制器消息接收与发送处理以及格式转换功能,实现可自动调节的通信路由控制器。经过实验研究表明,该控制器设计可增加数据传输次数,并提高数据传输准确率,同时控制效果较强,网络节点鲁棒性较好。     

Web网络下的异常路由数据监测技术研究

在Web网络环境下,路由器应用过程中利用信道传输介质数据会出现异常干扰数据,而传统路由数据监测技术很难准确辨别异常数据,并且存在不能承接Web网络的缺陷。针对上述问题,提出Web网络下的异常路由数据监测技术。对监控总框架进行优化设计,增设Web网络承接模块,导入多层次监测机制,通过Contra variant算法实现异常数据监测。设置仿真实验,实验结果表明,提出的数据监测技术能够有效地监控路由异常数据。     

RVCloud: a routing protocol for vehicular ad hoc network in city environment using cloud computing

Routing in Vehicular Ad hoc Network (VANET) is a challenging task due to high mobility of vehicles. In this paper, a RVCloud routing protocol is proposed for VANET to send the data efficiently to the destination vehicle using cloud computing technology. In this protocol, vehicle beacon information is send to the cloud storage through the Road Side Unit (RSU). As vehicles have less storage and computing facility, the information of all the vehicles moving in the city is maintained by the cloud. Source vehicle sends the data to the destination by sending the data to the nearby RSU. After receiving the data, RSU sends a request to the cloud for an optimal RSU information, that takes minimum packet forwarding delay to send the data to the destination. Cloud provides location service by providing destination location and optimal RSU information. Then RSU sends the data to the optimal RSU using internet. By using the internet facility, packet forwarding delay and link disruption problem are reduced. Simulation results show that, RVCloud performs better than VehiCloud, P-GEDIR, GyTAR, A-STAR, and GSR routing protocols.     

适应城市交通环境的改进型车载路由优化方法设计

为了优化城市交通环境中车载自组织网络中路由协议的链路存活时间、吞吐量等性能指标,在拓扑反应式路由协议的基础上,引入车载网络节点的位置信息,设计基于动态实时位置信息变化的车载路由协议优化模型。该模型按照十字路口车辆优先和相对位置为同方向节点优先转发的原则,根据路由信息表中位置信息区分转发控制包,并给出该路由算法的面向C++语言的UML建模图及其算法流程图。通过NS2仿真平台仿真表明,与传统的路由模型相比,该模型优化了VANETs网络中链路存活时间、时延、吞吐量等性能指标。     

基于社会环境的一种优化Prophet延迟容忍网络路由算法

在移动智能终端普及的今天,延迟容忍网络作为数据的补充传输方案具有重要的意义。在社会环境中,节点移动规律具有明显周期性,Prophet路由算法在该类场景中效果较好。因此文章提出了一种基于加强传统概率的路由算法,其在工作日模型下对E Prophet算法进行了仿真实验。实验结果表明,所提出的E Prophet算法在该场景下优于传统的Prophet算法。     

怒火救援

克雷斯(丹泽尔·华盛顿饰)是一名退伍特种部队队员,因对过去的所作所为充满愧疚而终日以酒精浇愁。朋友为他介绍了一份前往墨西哥城担任富家保镖的工作,当他到达之后发现他要保护的人是10岁的小女孩希达(达科塔·芬妮饰),以免被猖撅的黑社会绑票。然而防不胜防,已经和希达形成近似父女关系的克雷斯重伤之下也不能救得希达,得知希达被撕票的消患后克雷斯走上了疯     

WIND-FLEX: developing a novel testbed for exploring flexible radio concepts in an indoor environment

We describe the essential features of a novel testbed, code-named WIND-FLEX and developed under the auspices of the EU IST research program, whose primary goal has been to define and explore concepts related to radio flexibility, with application to an OFDM-based short-range indoor radio transceiver design. The emphasis has been on the profitable use of software and DSP tools for the purpose of demonstrating adaptivity and reconfigurability features, primarily for the lower layers (i.e., PHY and DLC/MAC layers). The topics covered briefly herein include the meaning of the terms in the present context, their instantiation in the design, their contribution to an optimized low-transmit-power scheme, the novel elements required in order to achieve it, the contribution to a guaranteed QoS philosophy, and the relationship of the testbed to broader software-defined-radio concepts.     

A flexible module library for custom DSP applications in amultiprocessor environment

The module library for the Cathedral-II synthesis environment is discussed. The underlying architectural style of the environment is defined as a hierarchical composition of flexible and parameterizable data paths, microcoded control units, interprocessor communication protocols, and input/output interfaces. A data path is called an execution unit (EXU), which consists of three parts: an input block, an output block, and a core. Only the core varies for the different EXUs. The topology and functionality of an EXU can be influenced by a set of parameters. The module library consists of two parts, a leaf-cell library and a procedure library, to place and interconnect the leaf cells to create functional building blocks that compose one EXU. The EXUs are guaranteed to work at 10 MHz. The described modules have been implemented and tested. The main features of this system are a very powerful parameterization, the technology independence of the CAD tools, and the generation speed of the modules. The current library is specially dedicated towards application-specific IC (ASIC) customized processors, although it can be used for more hardwired architectures, oriented towards higher throughput     

FIRE: a fault-independent combinational redundancy identificationalgorithm

FIRE is a novel Fault-Independent algorithm for combinational REdundancy identification. The algorithm is based on a simple concept that a fault which requires a conflict as a necessary condition for its detection is undetectable and hence redundant. FIRE does not use the backtracking-based exhaustive search performed by fault-oriented automatic test generation algorithms, and identifies redundant faults without any search. Our results on benchmark and real circuits indicate that we find a large number of redundancies (about 80% of the combinational redundancies in benchmark circuits), much faster than a test-generation-based approach for redundancy identification. However, FIRE is not guaranteed to identify all redundancies in a circuit     

浅水环境中基于熵的能量均衡路由优化算法

浅水环境具有覆盖面积小、水位低、水底环境较为复杂的特点,当在水下部署传感器节点时,其传输路径容易受到水底障碍物、水中杂物、水浪等影响,给水下传感器的路由选择带来困扰。针对浅水中传感器节点路由选择困难、能量消耗不均、生命周期短的问题,提出一种基于熵的能量均衡路由算法。该算法综合多种节点部署形式,在节点均匀分布和非均匀分布两种条件下分别计算传感器网络通信的能量损耗,权衡考虑节点的剩余能量和位置信息来选择下一跳节点,从而均衡网络能耗。利用NS-2仿真工具对该算法的性能进行仿真分析。结果表明该算法能够实现浅水中的节点通信,有效延长网络生命周期。