Intratumoral Thermal Reading During Photo‐Thermal Therapy by Multifunctional Fluorescent Nanoparticles

The tremendous development of nanotechnology is bringing us closer to the dream of clinical application of nanoparticles in photothermal therapies of tumors. This requires the use of specific nanoparticles that must be highly biocompatible, efficient light‐to‐heat converters and fluorescent markers. Temperature reading by the heating nanoparticles during therapy appears of paramount importance to keep at a minimum the collateral damage that could arise from undesirable excessive heating. In this work, this thermally controlled therapy is possible by using Nd³⁺ ion‐doped LaF₃ nanocrystals. Because of the particular optical features of Nd³⁺ ions at high doping concentrations, these nanoparticles are capable of in vivo photothermal heating, fluorescent tumor localization and intratumoral thermal sensing. The successful photothermal therapy experiments here presented highlight the importance of controlling therapy parameters based on intratumoral temperature measurements instead of on the traditionally used skin temperature measurements. In fact, significant differences between intratumoral and skin temperatures do exist and could lead to the appearance of excessive collateral damage. These results open a new avenue for the real application of nano­particle‐based photothermal therapy at clinical level.     

Direction of Arrival Estimation using EM-ESPRIT with Nonuniform Arrays

This paper deals with the problem of the Direction Of Arrival (DOA) estimation with nonuniform linear arrays. The proposed method is based on the Expectation Maximization method where ESPRIT is used in the maximization step. The key idea is to iteratively interpolate the data to a virtual uniform linear array in order to apply ESPRIT to estimate the DOA. The iterative approach allows one to improve the interpolation using the previously estimated DOA. One of this method’s novelties lies in its capacity of dealing with any nonuniform array geometry. This technique manifests significant performance and computational advantages over previous algorithms such as Spectral MUSIC, EM-IQML and the method based on manifold separation technique. EM-ESPRIT is shown to be more robust to additive noise. Furthermore, EM-ESPRIT fully exploits the advantages of using a nonuniform array over a uniform array: simulations show that for the same aperture and with a smaller number of sensors, the nonuniform array presents almost identical performance as the equivalent uniform array.     

WebAnalyzer: accurate detection of HTTP attack traces in web server logs

This paper presents a tool for detecting attacks against web server, using the analysis of web server log files. The main characteristic of this tool is its accuracy, being able to carefully graduate its analysis according to the actual success of the attacker. This capability is based on the design of a simple yet powerful signature definition language. We demonstrate the accuracy of the tool using a set of log lines representing several attack conditions and attack results.     

Improving mobile ad hoc network routing with satellite out‐of‐band signaling

Routing in mobile ad hoc networks is a complex task due to the mobility of the nodes and the constraints linked to a wireless multihop network (e.g., limited bandwidth, collisions, and bit errors). These adverse conditions impair not only data traffic but also routing signaling traffic, which feeds route computation. In this contribution, we propose to use satellite communications to help in the distribution of mobile ad hoc network routing signaling. The optimized link‐state routing (OLSR) is chosen among several routing protocols to be extended with satellite‐based signaling, yielding a version we call OLSR hybrid signaling (OLSR‐H). This new scheme is evaluated through simulations and yields improvements of approximately 10% in the data delivery ratio compared with a regular OLSR. This evaluation is conducted using two different network topology models, one being fit for representing forest firefighting operations. Copyright © 2013 John Wiley & Sons, Ltd.     

Quasi‐2D Colloidal Semiconductor Nanoplatelets for Narrow Electroluminescence

The first functional light‐emitting diodes (LEDs) based on quasi 2D colloidal core/shell CdSe/CdZnS nanoplatelets (NPLs). The solution‐processed hybrid devices are optimized with respect to their electroluminescent characteristics, first, by improving charge injection through exchanging the as‐synthesized NPL long‐chain ligands to shorter ones such as 3‐mercaptopropionic acid, and second, by comparing different hole‐transporting layers. NPL‐LEDs exhibit a maximum luminance of 4499 cd m^‐2 and external quantum efficiencies of 0.63%. In particular, over different applied voltages, systematically narrow electroluminescence of full width at half maximum (FWHM) in the range of 25–30 nm is observed to be independent from the choice of device configuration and NPL ligands. As spectrally narrow electroluminescence is highly attractive in terms of color purity in the context of LED applications, these results emphasize the unique potential of this new class of colloidal core/shell nanoplatelet in achieving bright and functional LEDs of superior color purity.     

A multimode CMOS PA with a single propagation path

Analog Integrated Circuits and Signal Processing - In this paper a four mode 130 nm RF CMOS power amplifier (PA) in a single propagation path topology is presented and evaluated with IEEE...     

Optimization methods for improving IP-level fast protection for local shared risk groups with Loop-Free Alternates

Lately, demand for fast failure recovery in IP networks has become compelling. The Loop-Free Alternates (LFA) specification is a simple IP Fast ReRoute (IPFRR) scheme proposed by the IETF that does not require profound changes to the network infrastructure before deployment. However, this simplicity comes at a severe price, because LFA does not provide complete protection for all possible failure cases in a general topology. This is even more so if network components are prone to fail jointly. In this paper, we study an important network optimization problem arising in this context, the so called LFA graph extension problem, which asks for augmenting the topology with new links in an attempt to improve the LFA failure case coverage. Unfortunately, this problem is NP-complete. The main contributions of the paper are a novel extension of the bipartite graph model for the LFA graph extension problem to the multiple-failure case using the model of Shared Risk Groups, and a suite of accompanying heuristics to obtain approximate solutions. We also compare the performance of the algorithms in extensive numerical studies and we conclude that the optimum can be approximated well in most cases relevant to practice.     

Detection of Channel Variations to Improve Channel Estimation Methods

In current digital communication systems, channel information is typically acquired by supervised approaches that use pilot symbols included in the transmit frames. Given that pilot symbols do not convey user data, they penalize throughput spectral efficiency, and transmit energy consumption of the system. Unsupervised channel estimation algorithms could be used to mitigate the aforementioned drawbacks although they present higher computational complexity than that offered by supervised ones. This paper proposes a simple decision method suitable for slowly varying channels to determine whether the channel has suffered a significant variation, which requires to estimate the matrix of the recently changed channel. Otherwise, a previous estimate is used to recover the transmitted symbols. The main advantage of this method is that the decision criterion is only based on information acquired during the time frame synchronization, which is carried out at the receiver. We show that the proposed criterion provides a considerable improvement of computational complexity for both supervised and unsupervised methods, without incurring in a penalization in terms of symbol error ratio. Specifically, we consider systems that make use of the popular Alamouti code. Performance evaluation is accomplished by means of simulated channels as well as making use of indoor wireless channels measured using a testbed.