H2O: An Autonomic, Resource-Aware Distributed Database System

This paper presents the design of an autonomic, resource-aware distributed database which enables data to be backed up and shared without complex manual administration. The database, H2O, is designed to make use of unused resources on workstation machines. Creating and maintaining highly-available, replicated database systems can be difficult for untrained users, and costly for IT departments. H2O reduces the need for manual administration by autonomically replicating data and load-balancing across machines in an enterprise. Provisioning hardware to run a database system can be unnecessarily costly as most organizations already possess large quantities of idle resources in workstation machines. H2O is designed to utilize this unused capacity by using resource availability information to place data and plan queries over workstation machines that are already being used for other tasks. This paper discusses the requirements for such a system and presents the design and implementation of H2O.Comment: Presented at SICSA PhD Conference 2010 (http://www.sicsaconf.org/

An Approach to Ad hoc Cloud Computing

We consider how underused computing resources within an enterprise may be harnessed to improve utilization and create an elastic computing infrastructure. Most current cloud provision involves a data center model, in which clusters of machines are dedicated to running cloud infrastructure software. We propose an additional model, the ad hoc cloud, in which infrastructure software is distributed over resources harvested from machines already in existence within an enterprise. In contrast to the data center cloud model, resource levels are not established a priori, nor are resources dedicated exclusively to the cloud while in use. A participating machine is not dedicated to the cloud, but has some other primary purpose such as running interactive processes for a particular user. We outline the major implementation challenges and one approach to tackling them

Towards Adaptable and Adaptive Policy-Free Middleware

We believe that to fully support adaptive distributed applications, middleware must itself be adaptable, adaptive and policy-free. In this paper we present a new language-independent adaptable and adaptive policy framework suitable for integration in a wide variety of middleware systems. This framework facilitates the construction of adaptive distributed applications. The framework addresses adaptability through its ability to represent a wide range of specific middleware policies. Adaptiveness is supported by a rich contextual model, through which an application programmer may control precisely how policies should be selected for any particular interaction with the middleware. A contextual pattern mechanism facilitates the succinct expression of both coarse- and fine-grain policy contexts. Policies may be specified and altered dynamically, and may themselves take account of dynamic conditions. The framework contains no hard-wired policies; instead, all policies can be configured.Comment: Submitted to Dependable and Adaptive Distributed Systems Track, ACM SAC 200

Insurance loss coverage and social welfare

Restrictions on insurance risk classification may induce adverse selection, which is usually perceived as a bad outcome, both for insurers and for society. However, a social benefit of modest adverse selection is that it can lead to an increase in `loss coverage', defined as expected losses compensated by insurance for the whole population. We reconcile the concept of loss coverage to a utilitarian concept of social welfare commonly found in economic literature on risk classification. For iso-elastic insurance demand, ranking risk classification schemes by (observable) loss coverage always gives the same ordering as ranking by (unobservable) social welfare

Insurance loss coverage under restricted risk classification: The case of iso-elastic demand

This paper investigates equilibrium in an insurance market where risk classification is restricted. Insurance demand is characterised by an iso-elastic function with a single elasticity parameter. We characterise the equilibrium by three quantities: equilibrium premium; level of adverse selection (in the economist’s sense); and “loss coverage”, defined as the expected population losses compensated by insurance. We consider both equal elasticities for high and low risk-groups, and then different elasticities. In the equal elasticities case, adverse selection is always higher under pooling than under risk-differentiated premiums, while loss coverage first increases and then decreases with demand elasticity. We argue that loss coverage represents the efficacy of insurance for the whole population; and therefore that if demand elasticity is sufficiently low, adverse selection is not always a bad thing

Estimating the volatility of property assets

When an investor is allocating assets between equities, bonds and property, this allocation needs to provide a portfolio with an appropriate risk/return trade-off: for instance, a pension scheme may prefer a robust portfolio that holds its aggregate value in a number of different situations. In order to do this, some estimate needs to be made of the volatility or uncertainty in the property assets, in order to use that in the same way as the volatilities of equities and bonds are used in the allocation. However, property assets are only valued monthly or quarterly (and are sold only rarely) whereas equities and bonds are priced continuously and recorded daily. Currently many actuaries may assume that the volatility of property assets is between those of equities and bonds, but without quantifying it from real data. The challenge for the Study Group is to produce a model for estimating the volatility or uncertainty in property asset values, for use in portfolio planning. The Study Group examined contexts for the use of volatility estimates, particularly in relation to solvency calculations as required by the Financial Services Authority, fund trustees and corporate boards, and it proposed a number of possible approaches. This report summarises that work, and it suggests directions for further investigation

Letter

"Angus MacDonald was Chief Trader at Fort Colville (originally spelled Colvile) and this letter was to his son-in-law, James McKenzie, a former Hudson's Bay Company clerk at the same fort.

The place names of the county of West Lothian

One of the first remarks made by the editors, of the Report on West Lothian of the Royal Commission on the Ancient and Historical Monuments of Scotland (Introduction xvii) concerns the sparseness of prehistoric monuments in the Lothians. This fact may partly be due to the heavily wooded and marshy state of the land, which compelled settlers to live either on the seashore or in forest clearances; and it is possible on this hypothesis that more intensive cultivation of the country has swept away such prehistoric remains as existed; it is possible also that the small number of monuments is due to the correspondingly small number of the inhabitants.Whatever is the reason - and both suggestions may be true in part - the scarcity of monuments is evident. There are a handful of flint implements, and a number of large constructions. There are three Cairns (Cairnpapple Hill, Earl Calrnie, and Laughing Hill) and one group of standing stones (Gala Braes, Bathgate); an early Iron Age grave has been discovered at Blackness, and there are several fortified sites, at Craigie Hill, Peace Knowe, Bowden Hill, and Cockleroy; one crannog has been listed, at Loch-cote, though it is probable that there was one also at Linlithgow; and two rocks with cup-markings, at Craigie Hill and at Dalmeny, are cited in the Introductio