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This work concerns efficient and reliable numerical simulations of the dynamic behaviour of a moving-boundary model for tubulin-driven axonal growth. The model is nonlinear and consists of a coupled set of a partial differential equation (PDE) and two ordinary differential equations. The PDE is defined on a computational domain with a moving boundary, which is part of the solution. Numerical simul
Recently, it has been shown that a parasitic element can be used to fully decouple closely spaced antennas. However, the decoupled antennas suffer from narrow bandwidth, as compared to the bandwidth of isolated single antennas, which is also the case for other decoupling methods, such as multiport conjugate match and neutralization line. In this paper, we investigate the potential in bandwidth enh
In this paper, we study the influence of current localization on the isolation between two antennas in a compact terminal setting. The two antennas are chosen to be a monopole and a PIFA, respectively. The degree of current localization is controlled by the permittivity value of the PIFA’s dielectric loading. Both lossless and lossy cases are simulated in order to ascertain the underlying performa
It is known that the compactness of mobile terminals complicates the design of multiple antennas, since coupling between the antennas increases when they are placed in proximity of one another. While it is possible to mitigate coupling between closely spaced antennas, a tradeoff in bandwidth is required. In this paper, we highlight ground plane excitation as an additional dimension to consider in
A simple and intuitive metric of multiplexing efficiency is proposed for evaluating the performance of MIMO antennas in the spatial multiplexing mode of operation. The metric is particularly useful for antenna engineers whose goal is to achieve the optimum antenna system design. Experimental results involving prototype mobile terminals highlight the effectiveness of our proposal.
Multiplexing efficiency is proposed as a simple and intuitive metric for characterizing multiple antenna systems in the spatial multiplexing mode of operation. Instead of comparing channel capacities of MIMO systems with different antennas, the metric offers valuable insights into the impact of antenna efficiency, efficiency imbalance and correlation on multiplexing performance. It is particularly
In this paper we describe our approach to robotic skill representation and a prototypical implementation of a programming-by-demonstration approach that allows users to generate skills and robot program primitives for later re- finement and re-use. We intend to evaluate the applicability of this approach to high-level programming in a user study, which we also explain.
Competition is an integrated part of most civilizations, from sports to education. Often competition arise whether or not it was intended and higher education is no exception from this. Should teachers acknowledge this and try to introduce competition as a part of the course or should they try to prevent competition, even spontaneously arisen competition? In this paper an overview of effects of co
In this paper, we study the performance of precoding schemes for cooperative transmission of multiple coherent base stations (BSs) that allow for overlapped clustering in a measured urban macrocellular environment at 2.66 GHz, in order to verify previous findings obtained by using simulated channel data. The evaluated precoding schemes include zero-forcing (ZF), layered virtual signal-to-interfere
Using antenna arrays for direction of arrival (DoA) estimation and source localization is a well-researched topic. In this paper, we analyze virtual antenna arrays for DoA estimation where the antenna array geometry is acquired using data from a low-cost inertial measurement unit (IMU). Performance evaluation of an unaided inertial navigation system with respect to individual IMU sensor noise para
This paper presents an efficient technique to enhance the isolation between two closely spaced PIFAs for MIMO mobile terminals. The proposed decoupling method is based on a T-shape slot impedance transformer and it enables an inter-PIFA spacing of 1 mm to be achieved. The 10 dB impedance bandwidth and 20 dB isolation bandwidth cover the 2.4 GHz WLAN band (2.4-2.48 GHz), with a maximum isolation of
Elasticity is the ability of a cloud infrastructure to dynamically change the amount of resources allocated to a running service as load changes. We build an autonomous elasticity controller that changes the number of virtual machines allocated to a service based on both monitored load changes and predictions of future load. The cloud infrastructure is modeled as a G=G=N queue. This model is used
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
A compact dual-element antenna suitable for ultrawideband (UWB) MIMO operation is proposed in this work. The size of the antenna is 25 mm by 40 mm and it covers the lower UWB band of 3.15-5.15 GHz. Apart from the inherent wideband isolation obtained through the different angle and polarization characteristics in the radiation patterns of the individual elements, the gap between the two antenna ele
