Supporting the Web with an information centric network that routes by name

Information Centric Networking (ICN) is a new paradigm in which the network layer provides users with content, instead of providing communication channels between hosts, and is aware of the name (or identifiers) of the contents. A fundamental ICN operation is the routing of content requests towards a node that is able to provide the requested content. To meet this goal, different routing architectures have been proposed so far.     

In-silico bonding schemes to encode chemical bonds involving sharing of electrons in molecular structures

Encoding of covalent and coordinate covalent bonds in molecular structures using ground state valence electronic configuration is achieved. The bonding due to electron sharing in the molecular structures is described with five fundamental bonding categories viz. uPair–uPair, lPair–uPair, uPair–lPair, vPair–lPair, and lPair–lPair. The involvement of lone pair electrons and the vacant electron orbitals in chemical bonding are explained with bonding schemes namely “target vacant promotion”, “source vacant promotion”, “target pairing promotion”, “source pairing promotion”, “source cation promotion”, “source pairing double bond”, “target vacant occupation”, and “double pairing promotion” schemes. The bonding schemes are verified with a chemical structure editor. The bonding in the structures like ylides, PCl₅, SF₆, IF₇, N-Oxides, BF₄⁻, AlCl₄⁻ etc. are explained and encoded unambiguously. The encoding of bonding in the structures of various organic compounds, transition metals compounds, coordination complexes and metal carbonyls is accomplished.     

Modeling multiple hop wireless networks with varying transmission power and data rate

Wireless multi-hop networks can vary both the transmission power and modulation of links. Those two parameters provide several design choices, which influence the performance of wireless multi-hop networks, e.g. minimize energy consumption, increase throughput, reduce contention, and maximize link quality. However, only network-wide metrics are considered in previous works. Further, per-flow performance metrics, such as the end-to-end energy consumption and latency, have not been studied. Those parameters directly impact the experience of users, which should be considered in capacity and performance studies. Our model incorporates per-flow metrics while also considering fading, contention, hidden terminals and packet error probabilities. We instantiate the model into an IEEE 802.11 multi-hop scenario, and evaluate common routing decisions such as maximizing link quality, maximizing data rate or minimizing the transmission power.     

基于TOPSIS的客舱布局选项评估要素分析方法

客舱布局的选择是机队规划过程中的重要部分。文中针对客舱布局方案评估问题,建立了以经济性、舒适性、通用性、维修性、适航性5个一级指标客舱布局的评价指标体系。通过对指标的合理量化以及相应指标的无量纲化,采用TOPSIS理论建立模型,通过计算接近度实现客舱布局备选方案的定量评价,并进行比较排序。最终,通过B787的5个客舱布局的方案实例分析结果表明,该方法的正确性和有效性。     

Path approximation for multi-hop wireless routing under application-based accuracy constraints

Provisioning of rich routing building blocks to mobile ad hoc networking applications has been of high interest. Several MANET applications need flexibility in describing paths their traffic will follow. To accommodate this need, previous work has proposed several viable routing schemes such as Dynamic Source Routing (DSR) and Trajectory-Based Routing (TBR). However, tradeoffs involved in the interaction of these routing schemes and the application-specific requirements have not been explored. Especially, techniques to help the application to do the right routing choices are much needed. In this paper, we consider techniques that minimize routing protocol state costs under application-based constraints. We study the constraint of “accuracy” of the application’s desired route, as this constraint provides a range of choices to the applications. As a crucial part of this concept, we investigate the tradeoff between the size of packet headers (needed to store end-to-end paths) and the network state (needed to store routing tables). We, then, apply the concept to the case of TBR with application-based accuracy constraints in obeying a given trajectory. We begin with simple discrete models to clarify the tradeoff between the packet header size and the network state. We show that the problem of accurate approximation of a trajectory (a.k.a. an application-specific end-to-end path) with the objective of minimizing the cost incurred due to header size and network state is difficult to solve optimally. We design an exhaustive search method as well as a genetic algorithm to find the optimum solution. We also develop heuristics solving this problem with smaller computational complexity and illustrate their performance. Finally, we explore ways of customizing our trajectory approximation framework for power-scarce or memory-scarce networking scenarios.     

A convex optimization approach for solving the single-vehicle cyclic inventory routing problem

This paper investigates the mathematical structure of the Single-Vehicle Cyclic Inventory Routing Problem (SV-CIRP). The SV-CIRP is an optimization problem consisting of finding a recurring distribution plan, from a single depot to a selected subset of retailers, that maximizes the collected rewards from the visited retailers while minimizing transportation and inventory costs. It appears as fundamental building block for all variants of the cyclic inventory routing problem (CIRP). One of the main complications in developing solution methods for the SV-CIRP using the current formulations is the non-convexity of the objective function. We demonstrate how the problem can be reformulated so that its continuous relaxation is a convex optimization problem. We further examine its mathematical properties and compare our findings with statements previously done in literature. Based of these findings we propose an algorithm that solves the SV-CIRP more effectively. We present experimental results on well-known benchmark instances, for which we are able to find optimal solutions for 22 out of 50 instances and obtained new best known solutions to 23 other instances.     

Carbon trading: Current schemes and future developments

This paper looks at the greenhouse gas (GHG) emissions trading schemes and examines the prospects of carbon trading. The first part of the paper gives an overview of several mandatory GHG trading schemes around the world. The second part focuses on the future trends in carbon trading. It argues that the emergence of new schemes, a gradual enlargement of the current ones, and willingness to link existing and planned schemes seem to point towards geographical, temporal and sectoral expansion of emissions trading. However, such expansion would need to overcome some considerable technical and non-technical obstacles. Linking of the current and emerging trading schemes requires not only considerable technical fixes and harmonisation of different trading systems, but also necessitates clear regulatory and policy signals, continuing political support and a more stable economic environment. Currently, the latter factors are missing. The global economic turmoil and its repercussions for the carbon market, a lack of the international deal on climate change defining the Post-Kyoto commitments, and unfavourable policy shifts in some countries, cast serious doubts on the expansion of emissions trading and indicate that carbon trading enters an uncertain period.     

On the numerical discretisation of stochastic oscillators

In this article, we propose an approach, based on the variation-of-constants formula, for the numerical discretisation over long-time intervals of several stochastic oscillators. Additive and multiplicative noises are treated separately. The proposed schemes permit the use of large step sizes in the presence of a high frequency in the problem and offer various additional properties. These new numerical integrators can be viewed as a stochastic-generalisation of the trigonometric integrators for highly oscillatory deterministic problems.     

巨厚坚硬岩浆岩不同配比的模型试验研究

针对工作面上覆巨厚坚硬岩浆岩条件,采用相似模拟的方法,研究了不同配比条件下岩浆岩的破断运移规律,对岩浆岩破断后诱发动力灾害进行了分析。研究表明:巨厚坚硬岩浆岩的配比不同岩浆岩的破断运移规律不同,当岩浆岩配比号为337时岩浆岩的初次破断是非全厚破断,破断后的岩块形状极不规则;当岩浆岩配比号为737时,坚硬巨厚岩浆岩初次破断为全厚破断,破断后的岩块形状成拱形;坚硬巨厚岩浆岩在失稳时释放大量的能量,能量传递到工作面,会对工作面产生冲击,导致工作面发生冲击地压。     

频谱灵活光网络应用策略研究

本文叙述了频谱灵活光网络的特点、功能和设备技术要点;结合1Tb/s传输系统应用,为其采用12.5GHz频谱隙进行了信道带宽分配;又通过对比各类路由频谱分配算法和频谱资源重构方式的效果,提出了实际应用中的选择建议;然后结合当前网络情况,从网络层次、结构、承载颗粒等方面出发,分析和论证了频谱灵活光网络的应用场景,以便指导其在实践中的具体应用和功能发挥。