Lateral displacements of commonly found gravity retaining walls in Sri Lanka due to seismic action

Gravity type retaining walls have been widely used to retain soil in Sri Lanka. However, it was reported that the performance of gravity type retaining walls during earthquake is poor. In view of the above, it was attempted in this study to develop a methodology to estimate the possible displacements of commonly found gravity retaining walls in Sri Lanka due to expected earthquakes. In addition, it was attempted to recommend an optimum shape for gravity retaining walls to minimize the possible displacements. This work was backed by Mononobe-Okabe theory and Newmark‟s sliding wedge analysis. Using Mononobe-Okabe analysis, threshold acceleration that would cause a relative displacement between retaining wall and soil, was found for different types of retaining walls. Using Newmark‟s method, an analytical model was developed to predict lateral displacements during seismic loadings. Then different acceleration-time histories of earthquakes, which are similar to those observed near Sri Lanka recently, were fed to the developed analytical model and the lateral displacements were found. Gravity retaining walls with a sloping back is found to give the least displacements, compared to the other types such as vertical and battered type gravity retaining walls for same acceleration-time history and to the same ground slope behind the retaining wall

IoTNetSim:A Modelling and Simulation Platform for End-to-End IoT Services and Networking

Internet-of-Things (IoT) systems are becoming increasingly complex, heterogeneous and pervasive, integrating a variety of physical devices and virtual services that are spread across architecture layers (cloud, fog, edge) using different connection types. As such, research and design of such systems have proven to be challenging. Despite the influx in IoT research and the significant benefits of simulation-based approaches in supporting research, there is a general lack of appropriate modelling and simulation platforms to create a detailed representation of end-to-end IoT services, i.e. from the underlying IoT nodes to the application layer in the cloud along with the underlying networking infrastructure. To aid researchers and practitioners in overcoming these challenges, we propose IoTNetSim, a novel self-contained extendable platform for modelling and simulation of end-to-end IoT services. The platform supports modelling heterogeneous IoT nodes (sensors, actuators, gateways, etc.) with their fine-grained details (mobility, energy profile, etc.), as well as different models of application logic and network connectivity. The proposed work is distinct from the current literature, being an all-in-one tool for end-to-end IoT services with a multi-layered architecture that allows modelling IoT systems with different structures. We experimentally validate and evaluate our IoTNetSim implementation using two very large-scale real-world cases from the natural environment and disaster monitoring IoT domains

RELATIONSHIP BETWEEN SOIL CONDITIONS AND OCCURRENCE OF ROOT ROT DISEASE IN A FOREST NURSERY AT KUBALPOLA.

Soil conditions influence the seasonal development and geographical distribution of soil-borne fungi and development of root diseases. Diseased seedlings and soil samples were collected from Kumbalpola nursery which is one of the largest teak nurseries in Sri Lanka. The results of the survey showed that almost 17% of seedling were affected by root rot. Rhizoctonia species, one of the soil inhabitants, was identified as the causal organism of root rot of teak. The fungal populations of infested and non-infested soils of the nursery were studied.The environmental factors which influence the severity of the disease, including soil moisture, soil pH, soil temperature, organic carbon, organic matter and nitrogen contents, were compared in both soils

Integrating SDN and NFV with QoS-aware service composition

Traditional networks are transformed to enable full integration of heterogeneous hardware and software functions, that are configured at runtime, with minimal time to market, and are provided to their end users on “as a service” principle. Therefore, a countless number of possibilities for further innovation and exploitation opens up. Network Function Virtualization (NFV) and Software-Defined Networking (SDN) are two key enablers for such a new flexible, scalable, and service-oriented network architecture. This chapter provides an overview of QoS-aware strategies that can be used over the levels of the network abstraction aiming to fully exploit the new network opportunities. Specifically, we present three use cases of integrating SDN and NFV with QoS-aware service composition, ranging from the energy efficient placement of virtual network functions inside modern data centers, to the deployment of data stream processing applications using SDN to control the network paths, to exploiting SDN for context-aware service compositions

Open access image repositories: high-quality data to enable machine learning research

Originally motivated by the need for research reproducibility and data reuse, large-scale, open access information repositories have become key resources for training and testing of advanced machine learning applications in biomedical and clinical research. To be of value, such repositories must provide large, high-quality data sets, where quality is defined as minimising variance due to data collection protocols and data misrepresentations. Curation is the key to quality. We have constructed a large public access image repository, The Cancer Imaging Archive, dedicated to the promotion of open science to advance the global effort to diagnose and treat cancer. Drawing on this experience and our experience in applying machine learning techniques to the analysis of radiology and pathology image data, we will review the requirements placed on such information repositories by state-of-the-art machine learning applications and how these requirements can be met

Judicious QoS using cloud overlays

We revisit the long-standing problem of providing network QoS to applications, and propose the concept of judicious QoS -- combining the cheaper, best effort IP service with the cloud, which offers a highly reliable infrastructure and the ability to add in-network services, albeit at higher cost. Our proposed J-QoS framework offers a range of reliability services with different cost vs. delay trade-offs, including: i) a forwarding service that forwards packets over the cloud overlay, ii) a caching service, which stores packets inside the cloud and allows them to be pulled in case of packet loss or disruption on the Internet, and iii) a novel coding service that provides the least expensive packet recovery option by combining packets of multiple application streams and sending a small number of coded packets across the more expensive cloud paths. We demonstrate the feasibility of these services using measurements from RIPE Atlas and a live deployment on PlanetLab. We also consider case studies on how J-QoS works with services up and down the network stack, including Skype video conferencing, TCP-based web transfers, and cellular access networks.First author draf

A model-driven engineering approach for the service integration of IoT systems

With the development of IoT devices and web services, the objects of the real world are more interconnected, which allows applications to extend their characteristics in different fields, including industrial or home environments, among other possible examples such as health, trade, transport, or agriculture. However, this development highlights the challenge of interoperability, because devices are heterogeneous and use different communication protocols and different data formats. For this reason, we propose a model for point-to-point integration in three-layer IoT applications: (a) hardware, which corresponds to the physical objects (controller, sensor and actuator), (b) communication, which is the bridge that allows the exchange of data between a MQTT queue and REST web services, and (c) integration, which establishes a sequence of transactions to coordinate the components of the system. For this purpose, a metamodel, a graphic editor and a code generator have been developed that allow the developer to design IoT systems formed by heterogeneous components without having in-depth knowledge of every hardware and software platform. In order to validate our proposal, a smart home scenario has been developed, with a series of sensors and actuators that combined show a complex behavior