Water and erosion damage to coastal structures: South Carolina Coast, Hurricane Hugo, 1989

Hurricane Hugo hit U.S. Mainland on September 21, 1989 just north of Charleston, South Carolina. It was billed as the most costly hurricane on record. The loss on the mainland alone exceeded 7 billion dollars, more than 15,000 homes were destroyed and the loss of lives exceeded forty. This article documents one aspect of the multi-destructions caused by the hurricane - the water and erosion damage on water front or near water front properties. A general damage survey was given first, followed by assessment on the performance of various engineered and non-engineering structures, on the major factors contributing to failures. Conclusions were then drawn with recommendations for future improvement. (26pp.

Effects of seawalls on the adjacent beach

This study was carried out to examine the effects of seawalls on the adjacent beach by three dimensional model test. The results obtained from model test were analyzed in terms of volumetric changes and shoreline and hydrographic change to quantify the effects of seawalls. The experiments were carried out in the wave basin of Coastal and Oceanographic Engineering department, University of Florida. A model seawall was installed on the test beach (19mxl4m) which was initially molded into equilibrium shapes. During the test, hydrographic surveys were conducted at regular time intervals. The main variable in the experiment is the wave angle. Cases both with and without seawall were tested. (141pp.

On Two-Pair Two-Way Relay Channel with an Intermittently Available Relay

When multiple users share the same resource for physical layer cooperation such as relay terminals in their vicinities, this shared resource may not be always available for every user, and it is critical for transmitting terminals to know whether other users have access to that common resource in order to better utilize it. Failing to learn this critical piece of information may cause severe issues in the design of such cooperative systems. In this paper, we address this problem by investigating a two-pair two-way relay channel with an intermittently available relay. In the model, each pair of users need to exchange their messages within their own pair via the shared relay. The shared relay, however, is only intermittently available for the users to access. The accessing activities of different pairs of users are governed by independent Bernoulli random processes. Our main contribution is the characterization of the capacity region to within a bounded gap in a symmetric setting, for both delayed and instantaneous state information at transmitters. An interesting observation is that the bottleneck for information flow is the quality of state information (delayed or instantaneous) available at the relay, not those at the end users. To the best of our knowledge, our work is the first result regarding how the shared intermittent relay should cooperate with multiple pairs of users in such a two-way cooperative network.Comment: extended version of ISIT 2015 pape