Identifying Conflicting Requirements in Systems of Systems

A System of Systems (SoS) is an arrangement of useful and independent sub-systems, which are integrated into a larger system. Examples are found in transport systems, nutritional systems, smart homes and smart cities. The composition of component sub-systems into an SoS enables support for complex functionalities that cannot be provided by individual sub-systems on their own. However, to realize the benefits of these functionalities it is necessary to address several software engineering challenges including, but not limited to, the specification, design, construction, deployment, and management of an SoS. The various component sub-systems in an SoS environment are often concerned with distinct domains; are developed by different stake-holders under different circumstances and time; provide distinct functionalities; and are used by different stakeholders, which allow for the existence of conflicting requirements. In this paper, we present a framework to support management of emerging conflicting requirements in an SoS. In particular, we describe an approach to support identification of conflicts between resource-based requirements (i.e. requirements concerned with the consumption of different resources). In order to illustrate and evaluate the work, we use an example of a pilot study of an IoT SoS ecosystem designed to support food security at different levels of granularity, namely individuals, groups, cities, and nations

Shape optimisation with multiresolution subdivision surfaces and immersed finite elements

We develop a new optimisation technique that combines multiresolution subdivision surfaces for boundary description with immersed finite elements for the discretisation of the primal and adjoint problems of optimisation. Similar to wavelets multiresolution surfaces represent the domain boundary using a coarse control mesh and a sequence of detail vectors. Based on the multiresolution decomposition efficient and fast algorithms are available for reconstructing control meshes of varying fineness. During shape optimisation the vertex coordinates of control meshes are updated using the computed shape gradient information. By virtue of the multiresolution editing semantics, updating the coarse control mesh vertex coordinates leads to large-scale geometry changes and, conversely, updating the fine control mesh coordinates leads to small-scale geometry changes. In our computations we start by optimising the coarsest control mesh and refine it each time the cost function reaches a minimum. This approach effectively prevents the appearance of non-physical boundary geometry oscillations and control mesh pathologies, like inverted elements. Independent of the fineness of the control mesh used for optimisation, on the immersed finite element grid the domain boundary is always represented with a relatively fine control mesh of fixed resolution. With the immersed finite element method there is no need to maintain an analysis suitable domain mesh. In some of the presented two- and three-dimensional elasticity examples the topology derivative is used for creating new holes inside the domain.The partial support of the EPSRC through grant # EP/G008531/1 and EC through Marie Curie Actions (IAPP) program CASOPT project are gratefully acknowledged.This is the final version of the article. It was first available from Elsevier via http://dx.doi.org/10.1016/j.cma.2015.11.01

A normalisation procedure for biaxial bias extension tests

Biaxial Bias Extension tests have been performed on a plain-weave carbon fibre engineering fabric. The test results have been normalised using both the upper and lower bound method proposed by Potluri et al. and also using a novel alternative normalisation method based on energy arguments. The normalised results from both methods are compared and discussed

Household water security through stored rainwater and consumer acceptability: a case study of the Anuradhapura District

Rainwater harvesting has increased in popularity in Sri Lanka over the past two decades due to the number of water supply projects funded by the government and non-governmental organizations (NGOs). The stored rainwater can provide accessible, reliable, timely and adequate supplies of water to households but there are uncertainties as to safety, in terms of water quality, and consumer acceptability. A study was, therefore, conducted in the Anuradhapura District, in the dry zone, to assess consumer acceptability of stored rainwater for household purposes and to conduct rainwater quality tests in a laboratory. The majority of households in Anuradhapura meet their drinking water requirements from protected wells (59.6 %). Prior to the project, people greatly preferred open wells as a source of domestic water, followed by tubewells, because they believed that water in open wells is of good quality and drinkable. However, stored rainwater has become the priority source now, especially through roof rainwater harvesting (RRWH), which is used during the dry periods. The study revealed that more than 85 % of households use stored rainwater for drinking although some have concerns over the quality and only drink it after boiling. The easy accessibility of water and the assurance by the project team that it is of good quality are the main reasons that people are willing to drink it. The acceptability of stored rainwater for consumption was very high in water-scarce areas and with the increasing distance to the nearest and alternative sources of good-quality water. Of those who felt that they had adequate water, 84 % of the sample households found it adequate in the wet season but only 21 % in the dry season. Water quality analysis revealed that the chemical and physical quality of stored rainwater is within the acceptable range with respect to Sri Lankan Standards, SLS: 614, for potable water quality (SLIS 1983). Other domestic water sources exceeded standards for electrical conductivity, total alkalinity, hardness, ammonium nitrogen, fluorides and total iron. However, stored rainwater was of lower biological quality than other domestic water sources.Length: pp.87-97Domestic waterWater securityWater harvestingWater qualityRural areasCase studies

Compliance with standards and immerging issues of household sewage disposal systems in Gampaha Municipality Area in Western Sri Lanka

Urban centers are highly significant with limited space together with the rising urban population. Most of the houses and buildings are attached with some kind of a sewage disposal facility as central sewage disposal systems are limited. Urbanization is expected to create many problems in terms of black water disposal due to limitation of land. A study was done in Gampaha municipality area, an urban center, where there is no central sewage treatment facility. The objectives of the study were to analyze the current situation of the black water disposal system in the study area and to identify the shortcomings of the black water disposal system comparing with the standards. The study was conducted within the urban center in five GN divisions. Random samples of 44 households were selected to represent all the five GN divisions. Selected households were interviewed to collect basic data needed and physical measurements were also taken where necessary. The data categories collected are household information, toilet type and size, desludging interval and distance to nearest well. The code of practice for the design and construction of septic tanks reports that 80% of urban communities use septic tanks for sewage disposal, but this study reveals that only 18% of the population uses septic tanks. Over 82% uses typical soakage pits that are constructed with loosely constructed brick walls and bare bottom open to soil for their sewage disposal. Over 68% of the households have their toilet pits within 15m to the nearest well, which is below the recommended distance. Only 30% of the households comply with over 15m to the nearest well that is recommended for septic tanks. The recommended distance for the soakage pits to the nearest well is 30m and only 9% of the households meet this standard. The black water disposal pits are over sized in general, so that the desludging interval is more than 10 years. Recently constructed houses, due to limitation of space, have reduced the size of the pits reducing the size of desludging interval. The construction and placement of septic tanks or soakage pits in the area have not complied with the standards

Engineering Adaptive Model-Driven User Interfaces

Software applications that are very large-scale, can encompass hundreds of complex user interfaces (UIs). Such applications are commonly sold as feature-bloated off-the-shelf products to be used by people with variable needs in the required features and layout preferences. Although many UI adaptation approaches were proposed, several gaps and limitations including: extensibility and integration in legacy systems, still need to be addressed in the state-of-the-art adaptive UI development systems. This paper presents Role-Based UI Simplification (RBUIS) as a mechanism for increasing usability through adaptive behaviour by providing end-users with a minimal feature-set and an optimal layout, based on the context-of- use. RBUIS uses an interpreted runtime model-driven approach based on the Cedar Architecture, and is supported by the integrated development environment (IDE), Cedar Studio. RBUIS was evaluated by integrating it into OFBiz, an open-source ERP system. The integration method was assessed and measured by establishing and applying technical metrics. Afterwards, a usability study was carried out to evaluate whether UIs simplified with RBUIS show an improvement over their initial counterparts. This study leveraged questionnaires, checking task completion times and output quality, and eye-tracking. The results showed that UIs simplified with RBUIS significantly improve end-user efficiency, effectiveness, and perceived usability

Using interpreted runtime models for devising adaptive user interfaces of enterprise applications

Although proposed to accommodate new technologies and the continuous evolution of business processes and business rules, current model-driven approaches do not meet the flexibility and dynamic needs of feature-rich enterprise applications. This paper illustrates the use of interpreted runtime models instead of static models or generative runtime models, i.e. those that depend on code generation. The benefit of interpreting runtime models is illustrated in two enterprise user interface (UI) scenarios requiring adaptive capabilities. Concerned with devising a tool-supported methodology to accommodate such advanced adaptive user interface scenarios, we propose an adaptive UI architecture and the meta-model for such UIs. We called our architecture Custom Enterprise Development Adaptive Architecture (CEDAR). The applicability and performance of the proposed approach are evaluated by a case study