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

Responding to unaccompanied minors in Scotland:policy and local authority perspectives

Following the provisions of the 2016 Immigration Act to permit the transfer of unaccompanied children the Scottish Government, COSLA, and local authorities have entered into negotiations with the Home Office to facilitate the arrival of children and young people to Scotland The present research sought to explore the capacity, experience and understanding of local authorities to provide a support system that can best ensure the wellbeing of children, as it has been suggested that outside of the large urban authorities there is limited experience of working with separated children.The study planned to conduct a survey across all 32 Scottish local authorities; undertake a qualitative analysis of key policy and guidance and to conduct focus group interviews with professionals in the field to explore in depth the findings of the first two stages. Due to access and engagement issues it was not possible to do focus group interviews. The findings of the report are based on the return of 14 questionnaires (44% of local authorities in Scotland) and a policy analysis of four key documents. As such the findings can be described as indicative, further work is required to explore further a number of the key issues identified.The Bacchian policy analysis indicated that some of the key guidance documents for local authorities and professionals are reluctant to engage with the more complex issues relating to children on the move, especially any reflection on the societal and geo-political reasons why children migrate in the first instance. Coupled with this there is also indication of language in documents that problematises routes of arrival that are not considered ‘legal’ and ‘safe’ thereby creating deserving and undeserving arrivals. Within the context of the documents there is concern that children are either characterised as either children or asylum seekers, when in fact they are both. While the guidance is useful for process and procedure, overall, the broader contextual analysis of children’s decisions to move is largely omitted, such that any ethical or sociological understanding of needs and responses is minimised.Local authorities are reporting higher numbers of unaccompanied children coming in to care with the number of local authorities who have over 10 in their care increasing; while official statistics are rarely published for the number of unaccompanied asylum seeking children in Scotland, it is estimated that at present local authorities are looking after approximately 140 separated children. For those local authorities that have larger numbers of children, there is greater familiarity with the processes and procedures, both in relation to immigration and welfare issues and legislation. Across all authorities there is some inconsistency in guidance consulted, with little indication of specific guidance in relation to unaccompanied children in use universally. Age assessments were the most common assessment undertaken by local authorities, although only three local authorities indicated they had consulted age assessment guidance. There was clear recognition of the needs presented by children and local authorities indicated they drew on the expertise of a number of partner agencies to support children and young people.While the present findings are limited by the number of local authorities responding, they indicate that understanding and responses to key issues and policy guidance varies substantially across local authorities in Scotland. These findings indicate children and young people may well receive different levels of service in different areas, with implications for both short and long term outcomes. While there is evidence of good work across the country, key questions remain about consistency and further, more in depth analysis of practice is required

RAFDA: A Policy-Aware Middleware Supporting the Flexible Separation of Application Logic from Distribution

Middleware technologies often limit the way in which object classes may be used in distributed applications due to the fixed distribution policies that they impose. These policies permeate applications developed using existing middleware systems and force an unnatural encoding of application level semantics. For example, the application programmer has no direct control over inter-address-space parameter passing semantics. Semantics are fixed by the distribution topology of the application, which is dictated early in the design cycle. This creates applications that are brittle with respect to changes in distribution. This paper explores technology that provides control over the extent to which inter-address-space communication is exposed to programmers, in order to aid the creation, maintenance and evolution of distributed applications. The described system permits arbitrary objects in an application to be dynamically exposed for remote access, allowing applications to be written without concern for distribution. Programmers can conceal or expose the distributed nature of applications as required, permitting object placement and distribution boundaries to be decided late in the design cycle and even dynamically. Inter-address-space parameter passing semantics may also be decided independently of object implementation and at varying times in the design cycle, again possibly as late as run-time. Furthermore, transmission policy may be defined on a per-class, per-method or per-parameter basis, maximizing plasticity. This flexibility is of utility in the development of new distributed applications, and the creation of management and monitoring infrastructures for existing applications.Comment: Submitted to EuroSys 200

DGD Gallery: Storage, sharing, and publication of digital research data

We describe a project, called the "Discretization in Geometry and Dynamics Gallery", or DGD Gallery for short, whose goal is to store geometric data and to make it publicly available. The DGD Gallery offers an online web service for the storage, sharing, and publication of digital research data.Comment: 19 pages, 8 figures, to appear in "Advances in Discrete Differential Geometry", ed. A. I. Bobenko, Springer, 201

Classification of changes in API evolution

Applications typically communicate with each other, accessing and exposing data and features by using Application Programming Interfaces (APIs). Even though API consumers expect APIs to be steady and well established, APIs are prone to continuous changes, experiencing different evolutive phases through their lifecycle. These changes are of different types, caused by different needs and are affecting consumers in different ways. In this paper, we identify and classify the changes that often happen to APIs, and investigate how all these changes are reflected in the documentation, release notes, issue tracker and API usage logs. The analysis of each step of a change, from its implementation to the impact that it has on API consumers, will help us to have a bigger picture of API evolution. Thus, we review the current state of the art in API evolution and, as a result, we define a classification framework considering both the changes that may occur to APIs and the reasons behind them. In addition, we exemplify the framework using a software platform offering a Web API, called District Health Information System (DHIS2), used collaboratively by several departments of World Health Organization (WHO).Peer ReviewedPostprint (author's final draft

Internames: a name-to-name principle for the future Internet

We propose Internames, an architectural framework in which names are used to identify all entities involved in communication: contents, users, devices, logical as well as physical points involved in the communication, and services. By not having a static binding between the name of a communication entity and its current location, we allow entities to be mobile, enable them to be reached by any of a number of basic communication primitives, enable communication to span networks with different technologies and allow for disconnected operation. Furthermore, with the ability to communicate between names, the communication path can be dynamically bound to any of a number of end-points, and the end-points themselves could change as needed. A key benefit of our architecture is its ability to accommodate gradual migration from the current IP infrastructure to a future that may be a ubiquitous Information Centric Network. Basic building blocks of Internames are: i) a name-based Application Programming Interface; ii) a separation of identifiers (names) and locators; iii) a powerful Name Resolution Service (NRS) that dynamically maps names to locators, as a function of time/location/context/service; iv) a built-in capacity of evolution, allowing a transparent migration from current networks and the ability to include as particular cases current specific architectures. To achieve this vision, shared by many other researchers, we exploit and expand on Information Centric Networking principles, extending ICN functionality beyond content retrieval, easing send-to-name and push services, and allowing to use names also to route data in the return path. A key role in this architecture is played by the NRS, which allows for the co-existence of multiple network "realms", including current IP and non-IP networks, glued together by a name-to-name overarching communication primitive.Comment: 6 page