The state of society in Ceylon as depicted in the "Saddharma-Ratnavaliya" and other Sinhalese literature of the thirteenth century.

This thesis is an attempt to reconstruct the state of society in Ceylon depicted by the Saddharma-ratnavaliya and other contemporary Sinhalese literature - that is, the society of roughly the thirteenth century A.D. Though piecemeal studies have been undertaken by different scholars at different times, hardly any attempts have been made to study, as a whole, the life and institutions of Ceylon. Thus our task is all the more difficult. Many points had to be left undecided owing to lack of evidence, and will have to remain so until further light is shed by future research. In making a study of this period one is made aware of the beginnings of the decline of Sinhalese culture. Whatever the field, whether art, architecture, or sculpture, little development can be seen. Perhaps Ceylon never recovered from the destruction and ruin caused by the alien foe during this period. The Saddharma-ratnavaliya, Pujavaliya, Vi?uddhi- marga-sannaya and Kav-silumina are the sources of our study. Other works of the preceding and succeeding periods have also been examined whenever it was necessary to find corroborative evidence. In this respect, the Maha-vamsa, Cula-vamsa, Saddharmalamkaraya and the inscriptions have proved of immense value and have been liberally quoted in support of our views. The material has been dealt with under different heads for convenience of treatment and the whole thesis is divided into three sections - Political, Religious and Social. It is needless to say that, though the material has been thus presented, in real life there was no such hard and fast compartmentalisation. All spheres of activity were vitally connected with each other and were deeply influenced by religious thought. We cannot speak of an ancient Sinhalese culture without realising how vitally Buddhistic it was. It is our hope that this thesis will prove some contribution to the understanding of the life and institutions of our ancient people

Robust access control framework for mobile cloud computing network

Unified communications has enabled seamless data sharing between multiple devices running on various platforms. Traditionally, organizations use local servers to store data and employees access the data using desktops with predefined security policies. In the era of unified communications, employees exploit the advantages of smart devices and 4G wireless technology to access the data from anywhere and anytime. Security protocols such as access control designed for traditional setup are not sufficient when integrating mobile devices with organization’s internal network. Within this context, we exploit the features of smart devices to enhance the security of the traditional access control technique. Dynamic attributes in smart devices such as unlock failures, application usage, location and proximity of devices can be used to determine the risk level of an end-user. In this paper, we seamlessly incorporate the dynamic attributes to the conventional access control scheme. Inclusion of dynamic attributes provides an additional layer of security to the conventional access control. We demonstrate that the efficiency of the proposed algorithm is comparable to the efficiency of the conventional schemes

Aquaculture knowledge to improve livelihoods

The Wayamba University and Calgary University in Canada are partners in a two year project to promote sustainable aquaculture knowledge mobilization to improve income and food security of the rural people in Sri Lanka

Environmental stochasticity and density dependence in animal population models

Biological management of populations plays an indispensable role in all areas of population biology. In deciding between possible management options, one of the most important pieces of information required by population managers is the likely population status under possible management actions. Population dynamic models are the basic tool used in deriving this information. These models elucidate the complex processes underlying the population dynamics, and address the possible consequences/merits of management actions. These models are needed to guide the population towards desired/chosen management goals, and therefore allow managers to make informed decisions between alternative management actions. The reliability that can be placed on inferences drawn from a model about the fate of a population is undoubtedly dependent on how realistically the model represents the dynamic process of the population. The realistic representation of population characteristics in models has proved to be somewhat of a thorn in the side of population biologists. This thesis focuses in particular on ways to represent environmental stochasticity and density dependence in population models. Various approaches that are used in building environmental stochasticity into population models are reviewed. The most common approach represents the environmental variation by changes to demographic parameters that are assumed to follow a simple statistical distribution. For this purpose, a distribution is often selected on the basis of expert opinion, previous practice, and convenience. This thesis assesses the effect of this subjective choice of distribution on the model predictions, and develops some objective criteria for that selection based on ecological and statistical acceptability. The more commonly used distributions are compared as to their suitability, and some recommendations are made. Density dependence is usually represented in population models by specifying one or more of the vital rates as a function of population density. For a number of reasons, a population-specific function cannot usually be selected based on data. The thesis develops some ecologically-motivated criteria for identifying possible function(s) that could be used for a given population by matching functional properties to population characteristics when they are known. It also identifies a series of properties that should be present in a general function which could be suitable for modelling a population when relevant population characteristics are unknown. The suitability of functions that are commonly chosen for such purposes is assessed on this basis. I also evaluate the effect of the choice of a function on the resulting population trajectories. The case where the density dependence of one demographic rate is influenced by the density dependence of another is considered in some detail, as in some situations it can be modelled with little information in a relatively function-insensitive way. The findings of this research will help in embedding characteristics of animal populations into population dynamics models more realistically. Even though the findings are presented in the context of slow-growing long-lived animal populations, they are more generally applicable in all areas of biological management

Environmental stochasticity and density dependence in animal population models

Biological management of populations plays an indispensable role in all areas of population biology. In deciding between possible management options, one of the most important pieces of information required by population managers is the likely population status under possible management actions. Population dynamic models are the basic tool used in deriving this information. These models elucidate the complex processes underlying the population dynamics, and address the possible consequences/merits of management actions. These models are needed to guide the population towards desired/chosen management goals, and therefore allow managers to make informed decisions between alternative management actions. The reliability that can be placed on inferences drawn from a model about the fate of a population is undoubtedly dependent on how realistically the model represents the dynamic process of the population. The realistic representation of population characteristics in models has proved to be somewhat of a thorn in the side of population biologists. This thesis focuses in particular on ways to represent environmental stochasticity and density dependence in population models. Various approaches that are used in building environmental stochasticity into population models are reviewed. The most common approach represents the environmental variation by changes to demographic parameters that are assumed to follow a simple statistical distribution. For this purpose, a distribution is often selected on the basis of expert opinion, previous practice, and convenience. This thesis assesses the effect of this subjective choice of distribution on the model predictions, and develops some objective criteria for that selection based on ecological and statistical acceptability. The more commonly used distributions are compared as to their suitability, and some recommendations are made. Density dependence is usually represented in population models by specifying one or more of the vital rates as a function of population density. For a number of reasons, a population-specific function cannot usually be selected based on data. The thesis develops some ecologically-motivated criteria for identifying possible function(s) that could be used for a given population by matching functional properties to population characteristics when they are known. It also identifies a series of properties that should be present in a general function which could be suitable for modelling a population when relevant population characteristics are unknown. The suitability of functions that are commonly chosen for such purposes is assessed on this basis. I also evaluate the effect of the choice of a function on the resulting population trajectories. The case where the density dependence of one demographic rate is influenced by the density dependence of another is considered in some detail, as in some situations it can be modelled with little information in a relatively function-insensitive way. The findings of this research will help in embedding characteristics of animal populations into population dynamics models more realistically. Even though the findings are presented in the context of slow-growing long-lived animal populations, they are more generally applicable in all areas of biological management

Learning under concept drift with follow the regularized leader and adaptive decaying proximal

Concept drift is the problem that the statistical properties of the data generating process change over time. Recently, the Time Decaying Adaptive Prediction (TDAP) algorithm1 was proposed to address the problem of concept drift. TDAP was designed to account for the effect of drifting concepts by discounting the contribution of previous learning examples using an exponentially decaying factor. The drawback of TDAP is that the rate of its decaying factor is required to be manually tuned. To address this drawback, we propose a new adaptive online algorithm, called Follow-the-Regularized-Leader with Adaptive Decaying Proximal (FTRL-ADP). There are two novelties in our approach. First, we derive a rule to automatically update the decaying rate, based on a rigorous theoretical analysis. Second, we use a concept drift detector to identify major drifts and reset the update rule accordingly. Comparative experiments with 14 datasets and 6 other online algorithms show that FTRL-ADP is most advantageous in noisy environments with real drifts.Accepted versio