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In view of the lack of an effective evaluation model for optical network survivability evaluation caused by geographical disasters, this paper has studied and proposed an evaluation model for optical network survivability considering geographical disasters, designed and proposed an evaluation index for survivability based on communication efficiency. On this basis, a survivability assessment method considering protection and unprotected conditions is proposed. Simulation results show that this method can effectively evaluate the invulnerability of optical networks under geographical disasters.

Reindeer (Rangifer tarandus) have lengthy seasonal migrations on land and their feet possess excellent locomotor characteristics that can adapt to complex terrains. In this study, the kinematics and vertical ground reaction force (GRF) of reindeer forelimb joints (interphalangeal jointb, metacarpophalangeal jointc, and wrist jointd) under walk, trot 1, and trot 2 were measured using a motion tracking system and Footscan pressure plates. Significant differences among different locomotor activities were observed in the joint angles, but not in changes of the joint angles (αb,αc,αd) during the stance phase. Peak vertical GRF increased as locomotor speed increased. Net joint moment, power, and work at the forelimb joints were calculated via inverse dynamics. The peak joint moment and net joint power related to the vertical GRF increased as locomotor speed increased. The feet absorbed and generated more energy at the joints. During different locomotor activities, the contribution of work of the forelimbs changed with both gait and speed. In the stance phase, the metacarpophalangeal joint absorbed more energy than the other two joints while trotting and thus performed better in elastic energy storage. The joint angles changed very little (∼5°) from 0 to 75% of the stance phase, which reflected the stability of reindeer wrist joints. Compared to typical ungulates, reindeer toe joints are more stable and the stability and energy storage of forelimb joints contribute to locomotor performance in reindeer.

Reindeer (Rangifer tarandus) have lengthy seasonal migrations on land and their feet possess excellent locomotor characteristics that can adapt to complex terrains. In this study, the kinematics and vertical ground reaction force (GRF) of reindeer forelimb joints (interphalangeal joint b, metacarpophalangeal joint c, and wrist joint d) under walk, trot 1, and trot 2 were measured using a motion tracking system and Footscan pressure plates. Significant differences among different locomotor activities were observed in the joint angles, but not in changes of the joint angles (αb, αc, αd) during the stance phase. Peak vertical GRF increased as locomotor speed increased. Net joint moment, power, and work at the forelimb joints were calculated via inverse dynamics. The peak joint moment and net joint power related to the vertical GRF increased as locomotor speed increased. The feet absorbed and generated more energy at the joints. During different locomotor activities, the contribution of work of the forelimbs changed with both gait and speed. In the stance phase, the metacarpophalangeal joint absorbed more energy than the other two joints while trotting and thus performed better in elastic energy storage. The joint angles changed very little (∼5°) from 0 to 75% of the stance phase, which reflected the stability of reindeer wrist joints. Compared to typical ungulates, reindeer toe joints are more stable and the stability and energy storage of forelimb joints contribute to locomotor performance in reindeer.

Forthcoming

International audience; Spatial models of port system evolution often depict linearly the emergence of hierarchy through successive concentration phases of originally scattered ports. The Chinese case provides a fertile ground for complementing existing works by a long-term perspective, given the early importance of river ports and seaports and the development irregularities caused by periods of closure and openness over time and across such a large land mass. In both qualitative and quantitative ways, this paper describes and analyses the changing spatial pattern of China's port system since the first unified empire (221bc). Main results underline a certain stability of the port system with regard to the location of main sea-river gateways, notwithstanding important regional shifts from one period to the other.

The growth of peripheral ports to dominant hubs has been well documented in North America and Europe, and has led to the elaboration of several theoretical models. However, although changes in containerization growth have been taking place in the South and East Asia in recent years, particularly in China, only a few studies have focused on this region. The Pearl (Zhujiang) River Delta (PRD) has a typical port system with hub and peripheral ports, and provides an excellent case for studying the Peripheral Challenge. This paper introduces the theoretical evidence of the Hayuth model and analyzes the evolution of the container port system in the PRD with five phases: 1) phase I: preconditions for change and phase II: initial container port development in the 1970s and early 1980s; 2) phase III: diffusion, consolidation, and port concentration in the middle and late 1980s; 3) phase IV: the load center in the 1990s; and (4) phase V: the Peripheral Challenge since the late 1990s. The results illustrate that the Shenzhen port presents mounting challenges to the Hong Kong port, descending from a transshipment hub of China to a regional load center of Southeast China. Furthermore, this paper explores five points that have led to the evolution of the port system in the PRD: 1) competition in the regional port systems; 2) different interested parties; 3) shift of investment strategies of international terminal operators; 4) integration of shipping networks and reorganization of carriers; and 5) cost-based competition.

http://geoscien.iga.ac.cn/EN/abstract/abstract9663.shtml; International audience; The popularization of container transport technology impacts greatly the development of container port system whose evolution theory focuses the influence of technology on spatial and temporal changes of port system, which is of important significance to the construction of port. Based on the review of research progress, we integrate the theoretical model of container port system proposed by Hayuth and Notterboom, in light of the newest characters and developing mechanism of port system in the world, and design an revised theoretical model of container port system which is divided into five spatial-temporal developing stages, including pre-containerization, introduction and experiment of technology, popularization of technology and centre of throughput, hub port, diffusion and offshore hub, regionalization of port. We describe the spatial characteristics of container port system in each developing stage in detail. Its last two developing stages are diffusion and offshore hub and regionalization result from the integrated effect of five aspects, including local restriction of hub port, change of container shipping network, integration of modern logistics resources, inland distribution network and inland terminal, macro-control of the Central Government and market mechanism of port construction. Then, we choose the Yangtze River Delta as a case study, and analyze the evolving process of container port system, especially its changes of spatial characteristics and developing mechanism, to validate the theoretical model of container port system.

The Internet has been a main method of image's transmission and storage. A significative problem is how to prevent illegal diffusion for some images. In this paper, we prefer an effective method of registering the decode program with the user's identity by which the installation procedure produces the registering number with processed chaotic sequence or random sequences.