Filetype
We focus on improving resilience of cloud services (e.g., e-commerce website), when correlated or cascading failures lead to computing capacity shortage. We study how to extend the classical cloud service architecture composed of a load-balancer and replicas with a recently proposed self-adaptive paradigm called brownout. Such services are able to reduce their capacity requirements by degrading us
Spatially-Coupled LDPC (SC-LDPC) codes have been recently shown to be very efficient for transmissions over nonergodic channels, in particular over block-fading channels [1]. In fact, it is possible to design a SC-LDPC code with any given code diversity [2]. In this work, we investigate the performance of SC-LDPC codes over block-fading channels, assuming a mismatch (or offset) between the first b
We introduce a mixed-integer optimization model for two-layer IP-over-Flexgrid networks, and present a cost study performed using the CPLEX package for the introduced model. The study concerns a generic German network with 12 nodes and 20 links in the optical layer, and a set of six IP traffic matrices with increasing demand volumes. The optimization assumes a hot-standby mechanism in the optical
We present a model for estimating the final keep/cancel decision point, on a per-feature basis, for scope inclusion in a future release. The Basic Lost Opportunity Estimation Model (BLOEM), based on data from a company that uses an agile-inspired software development model, supports feature selection when the time-dependent business value estimates change as the requirements analysis progresses. T
Measurement results of an analog channel decoder in 65 nm CMOS are presented. We target ultra compact and low power applications with low to medium throughput requirements. The decoding core is designed for (7,5)(8) convolutional codes and takes 0.104 mm(2) on silicon. The degrading effects of analog imperfections are investigated and the presented results allow power, performance and throughput t
Industry--academia collaboration is critical for empirical research to exist. However, there are many obstacles in the collaboration process. This paper reports on the experiences gained by the author, in a 2-year collaboration project on software testing which involved on-site work by the researcher in the industry premises. Based on notes, minutes of meetings, and progress reports, the project h
Reference attribute grammars (RAGs) is a powerful formalism for developing modular extensible compilers and program analysis tools. This paper presents JavaRAG, an implementation of RAGs as a Java library that is independent of the abstract syntax tree structure. This makes it possible to extend legacy compilers implemented in Java with RAG computations. We have evaluated the approach by integrati
This paper proposes a process independent post layout de-synchronization flow implemented in tool command language working on designs operating in the sub-V-T regime. The overhead due to the self-timed operation is combated by introducing full-custom delay elements and latches for a standard 65-nm CMOS process. The flow offers the possibility to adjust granularity based on user requirements. Case
Consider the communication model (y) over bar = H F (x) over bar + (n) over bar, where H; F are real-valued matrices, (x) over bar is a data vector drawn from some real-valued lattice (e.g. M-PAM), (n) over bar is additive white Gaussian noise and (y) over bar is the received vector. It is assumed that the transmitter and the receiver have perfect knowledge of the channel matrix H (perfect CSI) an
Shadowing from other vehicles can degrade the performance of vehicle-to-vehicle communication systems significantly. It is thus important to characterize and model the influence of common shadowing objects like trucks in a proper way. However, the scenario of a truck as an obstacle in highly dynamic rural and highway environments is not yet well understood. In this paper we analyze the distance de
We consider demand response solutions having the capability to monitor different variables at users' premises, like presence and temperature, and to control individual appliances. We focus on the optimal control of the appliances during time periods where the available capacity is not enough to satisfy the demand generated by houses operating freely. We propose an approach to define the utility of
In industry–academia collaboration projects, there are many issues related to different time horizons in industry and academia. If not adressed upfront, they may hinder collaboration in such projects. We analyze our experiences from a 10 year industry–academia collaboration program, the EASE Industrial Excellence Center in Sweden, and identify issues and feasible practices to overcome the hurdles
The use of large-scale antenna arrays can bring substantial improvements both in energy and spectral efficiency. This paper presents an initial study of user equipment (UE) antenna performance based on prototypes for a massive MIMO test bed. Most publications in the massive MIMO area have assumed isotropic or dipole antenna behavior at the UE side. It is, however, of greatest interest to evaluate
This paper presents the results of an accuracy study of a deterministic channel model for vehicle-to-vehicle (V2V) communications. Channel simulations obtained from the ray-tracing model developed by TU Braunschweig are compared to data gathered during the DRIVEWAY V2V channel measurement campaign at 5.6 GHz in the city of Lund in summer 2009. The analysis focuses on PDP and channel gains in an ur
In the software industry, there is a strong shift from traditional phase-based development towards agile methods and practices. This paper reports on a case study aimed at investigating if, and how, agile Requirements Engineering (RE) can remedy the challenges of traditional RE, and what new challenges agile RE may pose. The results from an initial case study with 9 practitioners from a large soft
To fulfill increasing requirements within the manufacturing sector, highly flexible and adaptable automation systems are needed. It is desirable to have one integrated approach that stretches from the process planning phase, through the implementation phase and all the way to the phase for execution of the process control logics. One promising approach is to use the concepts of service-oriented ar
This paper presents an analysis on energy dissipation of a digital half band filters operated in the the sub-threshold (sub-VT ) region with throughput constraints. The degradation of speed in the sub-VT domain is counteracted by unfolding the architectures. A filter is implemented in a basic 12-bit and its various unfolded structures. The designs are synthesized in a 65 nm low-leakage high-thresh
