Bootstrapping Real-world Deployment of Future Internet Architectures

The past decade has seen many proposals for future Internet architectures. Most of these proposals require substantial changes to the current networking infrastructure and end-user devices, resulting in a failure to move from theory to real-world deployment. This paper describes one possible strategy for bootstrapping the initial deployment of future Internet architectures by focusing on providing high availability as an incentive for early adopters. Through large-scale simulation and real-world implementation, we show that with only a small number of adopting ISPs, customers can obtain high availability guarantees. We discuss design, implementation, and evaluation of an availability device that allows customers to bridge into the future Internet architecture without modifications to their existing infrastructure

SDNsec: Forwarding Accountability for the SDN Data Plane

SDN promises to make networks more flexible, programmable, and easier to manage. Inherent security problems in SDN today, however, pose a threat to the promised benefits. First, the network operator lacks tools to proactively ensure that policies will be followed or to reactively inspect the behavior of the network. Second, the distributed nature of state updates at the data plane leads to inconsistent network behavior during reconfigurations. Third, the large flow space makes the data plane susceptible to state exhaustion attacks. This paper presents SDNsec, an SDN security extension that provides forwarding accountability for the SDN data plane. Forwarding rules are encoded in the packet, ensuring consistent network behavior during reconfigurations and limiting state exhaustion attacks due to table lookups. Symmetric-key cryptography is used to protect the integrity of the forwarding rules and enforce them at each switch. A complementary path validation mechanism allows the controller to reactively examine the actual path taken by the packets. Furthermore, we present mechanisms for secure link-failure recovery and multicast/broadcast forwarding.Comment: 14 page

Cost Estimate Modeling of Transportation Management Plans for Highway Projects, Research Report 11-24

Highway rehabilitation and reconstruction projects frequently cause road congestion and increase safety concerns while limiting access for road users. State Transportation Agencies (STAs) are challenged to find safer and more efficient ways to renew deteriorating roadways in urban areas. To better address the work zone issues, the Federal Highway Administration published updates to the Work Zone Safety and Mobility Rule. All state and local governments receiving federal aid funding were required to comply with the provisions of the rule no later than October 12, 2007. One of the rule’s major elements is to develop and implement Transportation Management Plans (TMPs). Using well-developed TMP strategies, work zone safety and mobility can be enhanced while road user costs can be minimized. The cost of a TMP for a road project is generally considered a high-cost item and, therefore, must be quantified. However, no tools or systematic modeling methods are available to assist agency engineers with TMP cost estimating. This research included reviewing TMP reports for recent Caltrans projects regarding state-of-the-art TMP practices and input from the district TMP traffic engineers. The researchers collected Caltrans highway project data regarding TMP cost estimating. Then, using Construction Analysis for Pavement Rehabilitation Strategies (CA4PRS) software, the researchers performed case studies. Based on the CA4PRS outcomes of the case studies, a TMP strategy selection and cost estimate (STELCE) model for Caltrans highway projects was proposed. To validate the proposed model, the research demonstrated an application for selecting TMP strategies and estimating TMP costs. Regarding the model’s limitation, the proposed TMP STELCE model was developed based on Caltrans TMP practices and strategies. Therefore, other STAs might require adjustments and modifications, reflecting their TMP processes, before adopting this model. Finally, the authors recommended that a more detailed step-by-step TMP strategy selection and cost estimate process be included in the TMP guidelines to improve the accuracy of TMP cost estimates

A Distributed Parallel Simulation Environment for Interoperability and Reusability of Models in Military Applications

Interoperability and reusability of models are main concerns in military simulation. In order to improve the interoperability and reusability of models, the model shall be separated with a particular simulation engine, and the modelling framework of models as well as the architecture of the simulation engine should be standardized. This paper describes the architecture and operational concept of simulation environment which has been developed to enhance interoperability an d reusability of models. We named this environment adaptive distributed parallel Simulation environment for Interoperable and reusable models (AddSIM). We suggested a modelling framework to promote model development, portability and interoperability with other models. Also, we proposed a layered architecture to modularise critical capabilities including kernel layer, tool/application layer, support/service layer and external interface. This means that models can be developed independently of a simulation engine and interfaced with it using API. To validate the application feasibility of AddSIM, we set up an anti-air missile engagement situation and performed simulation. In military simulation, it is expected that reusability and interoperability of models will be enhanced by using proposed AddSIM.Defence Science Journal, 2012, 62(6), pp.412-419, DOI:http://dx.doi.org/10.14429/dsj.62.147

Numerical simulation of oxygen transport in land-based aquaculture tank

Dissolved oxygen is an important indicator of the water quality and important for fish survival in aquaculture. The distribution of the dissolved oxygen is highly dependent on the flow motions, the pressure and the temperature of the water. With the development of computational fluid dynamics, the spatial and temporal distribution of dissolved oxygen in water can be predicted to evaluate and maintain the water quality. In the present study, a three-dimensional numerical model for predicting the dissolved oxygen and the water flow motions is developed. Oxygen transport in land-based aquaculture tanks is investigated by solving the Unsteady Reynolds-Averaged Navier–Stokes (URANS) equations combined with an additional species transport equation of the dissolved oxygen concentration. The volume of fluid (VOF) method is used to simulate the evolution of two-phase immiscible flows of the water and the air with an interface. The predicted dissolved oxygen concentrations (DOC) are in agreement with the experimental measurement which validate the present numerical model. The evolution of the DOC in the water and the water velocities are discussed based on the numerical simulations.publishedVersio