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Current trends strongly indicate a transition towards large-scale programmable networks with virtual network functions. In such a setting, deployment of distributed control planes will be vital for guaranteed service availability and performance. Moreover, deployment strategies need to be completed quickly in order to respond flexibly to varying network conditions. We propose an effective optimization approach that automatically decides on the needed number of controllers, their locations, control regions, and traffic routes into a plan which fulfills control flow reliability and routability requirements, including bandwidth and delay bounds. The approach is also fast: The algorithms for bandwidth and delay bounds can reduce the running time at the level of 50x and 500x, respectively, compared to state-of-the-art and direct solvers such as CPLEX. Altogether, our results indicate that computing a deployment plan adhering to predetermined performance requirements over network topologies of various sizes can be produced in seconds and minutes, rather than hours and days. Such fast allocation of resources that guarantees reliable connectivity and service quality is fundamental for elastic and efficient use of network resources. Funding details: 671639; Funding details: VINNOVA, 2018-00735; Funding details: Stiftelsen för Strategisk Forskning, SSF, RIT15-0075; Funding text 1: This work was supported in part by the Swedish Foundation for Strategic Research (SSF) Time Critical Clouds under Grant RIT15-0075, in part by the Commission of the European Union in terms of the 5G-PPP COHERENT project under Grant 671639, and in part by the Celtic Plus 5G-PERFECTA (Vinnova) under Grant 2018-00735.

Eliciting scalability requirements during agile software development is complicated and poorly described in previous research. This article presents a lightweight artifact for eliciting scalability requirements during agile software development: the ScrumScale model. The ScrumScale model is a simple spreadsheet. The scalability concepts underlying the ScrumScale model are clarified in this design science research, which also utilizes coordination theory. This paper describes the open banking case study, where a legacy banking system becomes open. This challenges the scalability of this legacy system. The first step in understanding this challenge is to elicit the new scalability requirements. In the open banking case study, key stakeholders from TietoEVRY spent 55 hours eliciting TietoEVRY's open banking project's scalability requirements. According to TietoEVRY, the ScrumScale model provided a systematic way of producing scalability requirements. For TietoEVRY, the scalability concepts behind the ScrumScale model also offered significant advantages in dialogues with other stakeholders., 36 pages, 7 figures, 6 tables, accepted for publication in Journal of Systems and Software

The Laser Interferometer Space Antenna (LISA) and its metrology chain have to fulfill stringent performance requirements to enable the space-based detection of gravitational waves. This implies the necessity of performance verification methods. In particular, the extraction of the interferometric phase, implemented by a phasemeter, needs to be probed for linearity and phase noise contributions. This Letter reports on a hexagonal quasimonolithic optical bench implementing a three-signal test for this purpose. Its characterization as sufficiently stable down to picometer levels is presented as well as its usage for a benchmark phasemeter performance measurement under LISA conditions. These results make it a candidate for the core of a LISA metrology verification facility., 5 pages, 4 figures

Building envelopes are perhaps the most influencing players on assuring indoor comfort conditions, in alliance with their impact on the sustainability and energy-efficiency of the building during operation. However, given the multitude of commercial solutions available on the market and the use of different criteria and inconsistent semantics among the existing categorization/classification systems of construction objects, there is still a need for uniformisation of the many regarding the main Prefabricated Enclosure Wall Panel Systems (PEWPS) for building applications. In such context, this paper firstly explores the distinct categories of off-site Modern Methods of Construction (MMC), and how can they be classified. Secondly, focus will be given to panelised systems, where the classification of PEWPS is thoroughly investigated. Lastly, a summarised literature review of selected innovative research trends in advanced building envelopes is presented, with positive consequences on the comfort, energy and environmental performance of buildings. The purpose of this research is to provide a comprehensive framework to understand which singularities and challenges are associated with PEWPS; This set of tools should be accessible to designers (and construction stakeholders in general) to realise how each building solution is supposed to work on the road to fulfilling user requirements, European Union’s Horizon 2020 research and innovation programme under grant agreement No. 723825, and by research unit FCT/UID/ECI/04450/2013 (RISCO), info:eu-repo/semantics/publishedVersion

In this paper, a new type of electric field sensor is proposed for the health and safety protection of inspection staff in high-voltage environments. Compared with the traditional power frequency electric field measurement instruments, the portable instrument has some special performance requirements and, thus, a new kind of double spherical shell sensor is presented. First, the mathematical relationships between the induced voltage of the sensor, the output voltage of the measurement circuit, and the original electric field in free space are deduced theoretically. These equations show the principle of the proposed sensor to measure the electric field and the effect factors of the measurement. Next, the characteristics of the sensor are analyzed through simulation. The simulation results are in good agreement with the theoretical analysis. The influencing rules of the size and material of the sensor on the measurement results are summarized. Then, the proposed sensor and the matching measurement system are used in a physical experiment. After calibration, the error of the measurement system is discussed. Lastly, the directional characteristic of the proposed sensor is experimentally tested.

System designers need to have insight in the response times of service systems to see if they meet performance requirements. We present a high-level evaluation technique to obtain the distribution of services completion times. It is based on a high-level domain-specific language that hides the underlying technicalities from the system designer. Under the hood, probabilistic real-time model checking technology is used iteratively to obtain precise bounds and probabilities. This allows reasoning about nondeterministic, probabilistic and real-time aspects in a single evaluation. To reduce the state spaces for analysis, we use two sampling methods (for measurements) that simplify the system model: (i) applying an abstraction on time by increasing the length of a (discrete) model time unit, and (ii) computing only absolute bounds by replacing probabilistic choices with non-deterministic ones. We use an industrial case on image processing of an interventional X-ray system to illustrate our approach.

With the ever-increasing call for connected vehicles and intelligent transportation applications, vehicular networking have been of significant focus recently. Demands for highly reliable communication challenge the current underlying technology and transformations in vehicular communication are discussed. The uMTC service of the next generation mobile networking system (i.e. 5G), which is based on D2D broadcast communication, is a promising enabler for broadcast-based C-ITS applications with strict reliability requirements. In this paper, we look at the resource management aspect of D2D communication technology to contribute to vehicular broadcasting with a higher level of reliability. In this regard, we propose a resource allocation scheme which is adaptive to the varying state of a vehicular network. With focus on the network load and topology as the main criteria, our scheme aims for management of the system capacity and interference situations, in order to meet the performance requirement of D2D vehicular broadcast, in terms of reliability. The results confirm the effectiveness of our approach and provide insight on the optimal network design regarding the allowed data rate and resource assignment according to application requirements. © 2017 IEEE. IEEE Seccion Espana; IFIP; IGIC; Telecom Escuela Tecnica VLC Superior de UPV INGENIEROS de Telecomunicacion; Universitat Politecnica de Valencia

Feedback control applications are robust to occasional deadline misses. This opens up the possibility of saving scarce (computation and communication) resources on embedded platforms. Stability and performance requirements of a control loop impose restrictions on acceptable patterns of deadline misses (e.g., not too many misses in a row). Such requirements are captured by (m,k)-firmness conditions. That is, at least m control computation jobs must meet deadlines in any k consecutive jobs. (m,k)-firm design requires (i) representation of stability and performance requirements in terms of (m,k)-firm deadlines (ii) controller synthesis taking into account the (m,k)-firmness parameters (iii) schedule analysis to verify guarantees on meeting the firmness conditions. We present a co-synthesis framework for these three design components and illustrate its applicability with examples. © 2018 IEEE.

During ground system conceptual design and engineering development many tradeoff decisions are made to balance functional performance, cost, risk, robustness, reliability, interoperability, growth margin, and other life-cycle characteristics. Tradespace analysis reveals and quantifies the compound and ripple effects and interactions among performance requirements and system design options. An analytic tradespace framework is an executable model that represents the logical and causal relationships among vehicle subsystems and system performance characteristics. Logical relationships define compatibility requirements between interacting subsystems. Causal relationships quantify higher level system attributes as functions of lower level subsystem attributes. Research at the US Army, TARDEC, has been developing a generic ground system performance specification framework, and a ground system standard product classification hierarchy. The current research seeks to integrate these two frameworks with a unifying framework of the logical and causal relationships. The tradespace framework identifies the relevant subsystem attributes and how they interact to govern product performance and life-cycle characteristics, and identifies the subsystem interfaces and compatibility characteristics that constrain and enable practical ground vehicles. The objective is a qualitative and quantitative framework integrating system architecture and technology options with functional and life cycle performance to support design and performance requirement decisions. The goal is to integrate the ground system architecture and performance specification frameworks for interactive tradespace analysis and exploration. The research is motivated by, and grounded in, an understanding of the performance and affordability tradespace decisions and supporting analysis in ground vehicle development programs.

The existing LTE network architecture dose not scale well to increasing demands due to its highly centralized and hierarchical composition. In this paper we discuss the major modifications required in the current LTE network to realize a decentralized LTE architecture. Next, we develop two IP address mobility support schemes for this architecture. The proposed solutions can handle traffic redirecting and seamless IP address continuity for the nodes moving among the distributed anchor points in a resource efficient manner. Our approaches are based on the SDN (Software Defined Networking) paradigm which is also one of the most important candidate technologies to realize 5G mobile networks. We extend the NS3-LENA simulation software to implement a decentralized LTE network as well as the proposed IP mobility support schemes. The evaluation results show that the proposed solutions efficiently fulfill the functionality and performance requirements (e.g., latency and packet loss) related to mobility management.

Intelligent Transportation Systems in the domain of vehicular networking, have recently been subject to rapid development. In vehicular ad hoc networks, data broadcast is one of the main communication types and its reliability is crucial for high performance applications. However, due to the lack of acknowledgment techniques in IEEE 802.11p standard, it is challenging to ensure communication reliability. In this work, we analytically model a receiver-oriented reliability mechanism, with the objective of on-demand error recovery for multi-hop broadcast vehicular communication. In particular, using absorbing Markov modeling and probabilistic graphical modeling, we analyze its performance in terms of relevant indicators, such as overhead and delivery ratio. Further, the model is validated using simulations. The results are useful in tuning the influential parameters and accordingly adjusting trade-offs and meet performance requirements in various circumstances.

International audience; Hyperspectral imaging (HI) collects information from across the electromagnetic spectrum, covering a wide range of wavelengths. The tremendous development of this technology within the field of remote sensing has led to new research fields, such as cancer automatic detection or precision agriculture, but has also increased the performance requirements of the applications. For instance, strong time constraints need to be respected, since many applications imply real-time responses. Achieving real-time is a challenge, as hyperspectral sensors generate high volumes of data to process. Thus, so as to achieve this requisite, first the initial image data needs to be reduced by discarding redundancies and keeping only useful information. Then, the intrinsic parallelism in a system specification must be explicitly highlighted. In this paper, the PCA (Principal Component Analysis) algorithm is implemented using the RVC-CAL dataflow language, which specifies a system as a set of blocks or actors and allows its parallelization by scheduling the blocks over different processing units. Two implementations of PCA for hyperspectral images have been compared when aiming at obtaining the first few principal components: first, the algorithm has been implemented using the Jacobi approach for obtaining the eigenvectors; thereafter, the NIPALS-PCA algorithm, which approximates the principal components iteratively, has also been studied. Both implementations have been compared in terms of accuracy and computation time; then, the parallelization of both models has also been analyzed. These comparisons show promising results in terms of computation time and parallelization: the performance of the NIPALS-PCA algorithm is clearly better when only the first principal component is achieved, while the partitioning of the algorithm execution over several cores shows an important speedup for the PCA-Jacobi. Thus, experimental results show the potential of RVC-CAL to automatically generate implementations which process in real-time the large volumes of information of hyperspectral sensors, as it provides advanced semantics for exploiting system parallelization. © 2016 SPIE.

This paper deals with the design of an electromechanical device considering some prescribed performance requirements, and static and dynamic analysis of this device are carried out. In studying the transient response of such a system, as part of dynamic analysis, two methods mostly used finite element method (FEM) and finite differences method (FDM). However, these methods need much CPU time. In this work, a computer simulator program is developed for an EMA. This technique is implemented in the MATLAB-Simulink environment and tested for different design tasks such as electromagnetic valves or electromechanical brakes etc. Furthermore, by using GUIDE tools within MATLAB, a simple useful and user-friendly GUI structure is developed to provide a visual approach to design and analysis process. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 383–396, 2010; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20279

International audience; The validation of systems and specifically the conformance testing of communicating protocols is a crucial step to their development. Many approaches have been developed for a while, among which, the formal ones have proved their efficiency to test these protocols. These approaches are divided in two main sets: active and passive testing techniques. While they both have their own advantages and drawbacks, passive testing techniques are the only ones that can be applied when the controllability of the system interfaces is unavailable or when the implementation under test cannot be stimulated in runtime. In this paper, we present a logic-based passive testing approach to test in a formal way the conformance and the protocol performance requirements provided by the protocol standard or experts.We aim at formally specifying time related protocol properties in order to check them on real execution traces. Based on a new algorithm, a prototype is here developed and experienced. In order to evaluate and assess our technique, we present experiments through a set of IMS/SIP properties (regarding the conformance and the protocol performance) and execution traces. We finally discuss the results by providing relevant verdicts

We assess the energy efficiency of mobile networks in 2020, and compare it with a 2010 baseline. A comprehensive assessment approach is taken, considering all relevant scenario aspects such as data traffic growth, hardware evolutions, mobile network deployments and operations including network sharing and the dynamic switching on/off of radio resources. In order to show the best technical capacities of mobile networks in achieving energy efficiency in 2020, while ensuring a fair comparison with the 2010 baseline scenarios, we apply a realistically appropriate approach for network dimensioning, determining suitable site densities that are in line with up- and downlink coverage and performance requirements. The results show an energy efficiency improvement factor of about 793 in 2020 over 2010.

Conference of 2013 IEEE 24th International Conference on Application-Specific Systems, Architectures and Processors, ASAP 2013 ; Conference Date: 5 June 2013 Through 7 June 2013; Conference Code:98904; International audience; Embedded systems are increasingly complex and heterogeneous to deal with increasing performance requirements along with wider ranges of application domains. The architecture of such systems often includes different kinds of computing resources and accelerators (DSPs, GPUs, etc.). Thus, application developers are facing important portability issues to adapt their software code to take maximum advantage of available processing elements. Consequently, software stacks rely more and more on virtualization technologies, leveraging Just-In-Time compilation to maximize performance of applications. Nevertheless, the efficiency of Just-In-Time compilation depends on the ability to compensate its overhead with execution speedups of generated code. In this paper, we propose a solution based on a dedicated processor with specialized instructions for critical functions to improve efficiency of code generators. These specialized instructions provide an average 5× speedup on manipulations of associative arrays and dynamic memory allocation. Based on the LLVM framework, we show a 15% overall speedup on code generator's execution time. Because our specialized instructions are hidden behind standard libraries, we also argue that these instructions may be transparently reused for a wider range of applications.

International audience; Performance testing of communicating protocols is a qualitative and quantitative evaluation of a system, aiming to check whether the performance requirements have been satisfied under certain conditions. It raises an interesting issue: how to formalize the specified detailed performance requirements by taking consideration of data values of the messages. The passive testing techniques are approaches that can be applied when the controllability of the system interfaces is unavailable or when the implementation under test cannot be stimulated in runtime. In this paper, we present a novel logic-based passive testing approach in specifying time related protocol properties to be tested on real execution traces. Based on a new algorithm, a prototype is developed and experienced. In order to evaluate and assess our approach, we present experiments through a set of IMS/SIP properties and real execution traces. Finally, relevant verdicts and discussions are provided

The development of distributed systems is generally regarded as a complex and costly task, and for this reason formal description techniques such as LOTOS and ESTELLE (both standardized by the ISO) are increasingly used in this process. Our experience is that LOTOS can be exploited at many stages on the design trajectory, from requirements specification to implementation, but that the language elements do not allow direct formalization of performance requirements. To avoid duplication of effort by using two formalisms with distinct approaches, we propose a design method that incorporates performance constraints in an heuristic but effective manner.