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Data volumes in communication networks increase rapidly. Further, usage of social network applications is very wide spread among users, and among these applications, Facebook is the most popular. In this paper, we analyse user demands patterns and content popularity of Facebook generated traffic. The data comes from residential users in two metropolitan access networks in Sweden, and we analyse mo
In this paper we describe a systematic study on long-term evolution of residential broadband Internet traffic covering 5 calendar years from June 2007 to May 2011. The traffic evolution is characterized both in the term of the total traffic volume, as well as the traffic volumes and shares for different application categories (file sharing, video streaming etc.), with the focus on comparing the tr
The presented study deals with a specific rerouting strategy for protecting traffic flows in communication networks called Flow Adjustment Routing. The strategy is designed to handle partial link failures. We present two variants of the strategy and analyze their pros and cons. We show that the initial strategy is not directly implementable to cope with severe link failures such as total link fail
In software product line engineering, testing for regression concerns not only versions, as in one-off product development, but also regression across variants. We propose a 3D process model, with the dimensions of level, version and variant, to help analyze, plan and manage software product line testing. We derive the model from empirical observations of regression testing practice and software p
It is well-known that the radio wave propagation mechanisms inside a tunnel are different from the typical outdoor and indoor situations. Since the tunnels represent a significant type of vehicular environments, understanding the channel characteristics for the in-tunnel scenario is crucial for intelligent transport systems design. A widely used tool for simulating channel characteristics for outd
Retrospective analysis of agile projects can support identification of issues through team reflection and may enable learning and process improvements. Basing retrospectives primarily on experiences poses a risk of memory bias as people may remember events differently, which can lead to incorrect conclusions. This bias is enhanced in project retrospectives which cover a longer period compared to i
TV-on-Demand service has become one of the most popular Internet applications that continuously attracts higher user interests. With rapidly increasing user demand, the existing network conditions may not be able to ensure low start-up delay of video playback. Prefetching has been broadly investigated to cope with the start-up latency problem which is also known as user perceived latency. In this
Due to changes in the development practices at Axis Communications, towards continuous integration, faster regression testing feedback is needed. The current automated regression test suite takes approximately seven hours to run which prevents developers from integrating code changes several times a day as preferred. Therefore we want to implement a highly selective yet accurate regression testing
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
A order 3-bit continuous-time (CT) ΔΣ ADC is presented in this paper. The design equations starting from a discrete-time reference modulator to the circuit implementation are given. The non-return to zero (NRZ) DAC pulses have a half clock cycle loopdelay which is corrected by the feedforward (also known as PI) loop delay compensation, and nonlinearities in the DACs are suppressed by data-weighted
[Context and Motivation] The main role of requirements engineering (RE) is to guide development projects towards implementing products that will appeal to customers. To effectively achieve this RE needs to be coordinated with and clearly communicated to the later software development activities. [Question/Problem] Communication gaps between RE and other development activities reduce coordination a
Pervasive middleware systems are important for enabling the configuration and coordination of the services provided by devices in pervasive environments. PalCom is an example of such a system that aims to enable interaction among pervasive services over heterogeneous networks. In this paper we discuss the need for providing networking-media independent messaging among pervasive devices, and identi
Clustering is a key concept of existing MIMO channel models, such as the COST 2100 model. Parameter based clustering has been studied for a while, but how parameter based clusters relate to the physical environment is not well known yet. A measurement based ray launching tool is developed and used for studying clustering and its relation to physical scatterers. By using estimated angles and delays
The problem of burst losses in OBS networks has an impact on the service quality perceived by end users. In order to guarantee certain level of Service Quality (QoS) in terms of burst losses, wavelength resources have to be dimensioned properly. In this paper, we address the problem of the Virtual Topology (VT) design that concerns the establishment of explicit routing paths and the allocation of
This article presents an architecture of a Digital Front-End Receiver (DFE-Rx) for the next-generation mobile terminals. A main focus is placed in flexibility, scalability and concurrency. The architecture is capable of detecting, synchronizing and reporting carrier-frequency offset, of multiple concurrent radio standards. The proposed receiver is fabricated in a 65nm CMOS low power high-VT cell t
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
In conventional MIMO, propagation conditions are often considered wide-sense stationary over the entire antenna array. In massive MIMO systems, where arrays can span over large physical dimensions, the situation is quite different. For instance, significant variations in signal strength, due to shadowing, can be experienced across a large array. These effects vary with propagation environment in w
