245,819 research outputs found
Feasibility study of a heat recovery system in an office building in Malta
The new Energy Performance of Buildings Directive (EU) 2018/844 has brought
about a new drive to renovate existing buildings, especially for heating and cooling systems,
whereby heat recovery techniques have become the order of the day. However, the real energy
and financial benefits of applying such techniques have not been studied in Malta, which has a
temperate Mediterranean climate. Thus, this study has performed a technical and financial
analysis of using different heat recovery options for the most common office type, that is a
medium-sized flatted office, using EnergyPlus dynamic simulation tool and multiple linear
regressions. Results showed that the coefficient of performance of the air-conditioners, the
window to wall ratio and the cooling set-point temperatures, have the greatest impact, while heat
recovery has an insignificant contribution to energy efficiency, thus making it rank low in the
list of energy efficiency priority measures for medium-sized offices in Malta.peer-reviewe
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Modeling software design diversity
Design diversity has been used for many years now as a means of achieving a degree of fault tolerance in software-based systems. Whilst there is clear evidence that the approach can be expected to deliver some increase in reliability compared with a single version, there is not agreement about the extent of this. More importantly, it remains difficult to evaluate exactly how reliable a particular diverse fault-tolerant system is. This difficulty arises because assumptions of independence of failures between different versions have been shown not to be tenable: assessment of the actual level of dependence present is therefore needed, and this is hard. In this tutorial we survey the modelling issues here, with an emphasis upon the impact these have upon the problem of assessing the reliability of fault tolerant systems. The intended audience is one of designers, assessors and project managers with only a basic knowledge of probabilities, as well as reliability experts without detailed knowledge of software, who seek an introduction to the probabilistic issues in decisions about design diversity
Reconfigurable Mobile Multimedia Systems
This paper discusses reconfigurability issues in lowpower hand-held multimedia systems, with particular emphasis on energy conservation. We claim that a radical new approach has to be taken in order to fulfill the requirements - in terms of processing power and energy consumption - of future mobile applications. A reconfigurable systems-architecture in combination with a QoS driven operating system is introduced that can deal with the inherent dynamics of a mobile system. We present the preliminary results of studies we have done on reconfiguration in hand-held mobile computers: by having reconfigurable media streams, by using reconfigurable processing modules and by migrating functions
Cloud engineering is search based software engineering too
Many of the problems posed by the migration of computation to cloud platforms can be formulated and solved using techniques associated with Search Based Software Engineering (SBSE). Much of cloud software engineering involves problems of optimisation: performance, allocation, assignment and the dynamic balancing of resources to achieve pragmatic trade-offs between many competing technical and business objectives. SBSE is concerned with the application of computational search and optimisation to solve precisely these kinds of software engineering challenges. Interest in both cloud computing and SBSE has grown rapidly in the past five years, yet there has been little work on SBSE as a means of addressing cloud computing challenges. Like many computationally demanding activities, SBSE has the potential to benefit from the cloud; âSBSE in the cloudâ. However, this paper focuses, instead, of the ways in which SBSE can benefit cloud computing. It thus develops the theme of âSBSE for the cloudâ, formulating cloud computing challenges in ways that can be addressed using SBSE
Open-TEE - An Open Virtual Trusted Execution Environment
Hardware-based Trusted Execution Environments (TEEs) are widely deployed in
mobile devices. Yet their use has been limited primarily to applications
developed by the device vendors. Recent standardization of TEE interfaces by
GlobalPlatform (GP) promises to partially address this problem by enabling
GP-compliant trusted applications to run on TEEs from different vendors.
Nevertheless ordinary developers wishing to develop trusted applications face
significant challenges. Access to hardware TEE interfaces are difficult to
obtain without support from vendors. Tools and software needed to develop and
debug trusted applications may be expensive or non-existent.
In this paper, we describe Open-TEE, a virtual, hardware-independent TEE
implemented in software. Open-TEE conforms to GP specifications. It allows
developers to develop and debug trusted applications with the same tools they
use for developing software in general. Once a trusted application is fully
debugged, it can be compiled for any actual hardware TEE. Through performance
measurements and a user study we demonstrate that Open-TEE is efficient and
easy to use. We have made Open- TEE freely available as open source.Comment: Author's version of article to appear in 14th IEEE International
Conference on Trust, Security and Privacy in Computing and Communications,
TrustCom 2015, Helsinki, Finland, August 20-22, 201
COST Action IC 1402 ArVI: Runtime Verification Beyond Monitoring -- Activity Report of Working Group 1
This report presents the activities of the first working group of the COST
Action ArVI, Runtime Verification beyond Monitoring. The report aims to provide
an overview of some of the major core aspects involved in Runtime Verification.
Runtime Verification is the field of research dedicated to the analysis of
system executions. It is often seen as a discipline that studies how a system
run satisfies or violates correctness properties. The report exposes a taxonomy
of Runtime Verification (RV) presenting the terminology involved with the main
concepts of the field. The report also develops the concept of instrumentation,
the various ways to instrument systems, and the fundamental role of
instrumentation in designing an RV framework. We also discuss how RV interplays
with other verification techniques such as model-checking, deductive
verification, model learning, testing, and runtime assertion checking. Finally,
we propose challenges in monitoring quantitative and statistical data beyond
detecting property violation
SmartUnit: Empirical Evaluations for Automated Unit Testing of Embedded Software in Industry
In this paper, we aim at the automated unit coverage-based testing for
embedded software. To achieve the goal, by analyzing the industrial
requirements and our previous work on automated unit testing tool CAUT, we
rebuild a new tool, SmartUnit, to solve the engineering requirements that take
place in our partner companies. SmartUnit is a dynamic symbolic execution
implementation, which supports statement, branch, boundary value and MC/DC
coverage. SmartUnit has been used to test more than one million lines of code
in real projects. For confidentiality motives, we select three in-house real
projects for the empirical evaluations. We also carry out our evaluations on
two open source database projects, SQLite and PostgreSQL, to test the
scalability of our tool since the scale of the embedded software project is
mostly not large, 5K-50K lines of code on average. From our experimental
results, in general, more than 90% of functions in commercial embedded software
achieve 100% statement, branch, MC/DC coverage, more than 80% of functions in
SQLite achieve 100% MC/DC coverage, and more than 60% of functions in
PostgreSQL achieve 100% MC/DC coverage. Moreover, SmartUnit is able to find the
runtime exceptions at the unit testing level. We also have reported exceptions
like array index out of bounds and divided-by-zero in SQLite. Furthermore, we
analyze the reasons of low coverage in automated unit testing in our setting
and give a survey on the situation of manual unit testing with respect to
automated unit testing in industry.Comment: In Proceedings of 40th International Conference on Software
Engineering: Software Engineering in Practice Track, Gothenburg, Sweden, May
27-June 3, 2018 (ICSE-SEIP '18), 10 page
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