Conformal phased array with beam forming for airborne satellite communication

For enhanced communication on board of aircraft novel antenna systems with broadband satellite-based capabilities are required. The installation of such systems on board of aircraft requires the development of a very low-profile aircraft antenna, which can point to satellites anywhere in the upper hemisphere. To this end, phased array antennas which are conformal to the aircraft fuselage are attractive. In this paper two key aspects of conformal phased array antenna arrays are addressed: the development of a broadband Ku-band antenna and the beam synthesis for conformal array antennas. The antenna elements of the conformal array are stacked patch antennas with dual linear polarization which have sufficient bandwidth. For beam forming synthesis a method based on a truncated Singular Value Decomposition is proposed

Analysis of Radar Absorbing FSS on Foldcores and Honeycombs

The objective of the paper is to investigate the radar absorption of honeycombs and foldcores with printed conductive patterns. These structures can be manufactured by first printing conductive Frequency Selective Surfaces (FSS) on planar substrates, which then can be used to shape foldcores and honeycombs by means of specific manufacturing technologies. Foldcores can be considered as intermediate shapes between planar sheets (where the printed patterns are perpendicular to the impinging radar waves) and honeycombs (where the printed patterns are parallel to the impinging radar wave). It is shown that the radar absorbing properties of the design strongly depend on the electrical conductivity of the paint, the size of the printed patterns and the orientation of the printed patterns with respect to the impinging wave. It is shown that a planar FSS has a maximum absorption of 50%, while foldcores and honeycombs may obtain a higher absorption due to the fact that the patterns are orientated under an angle with respect to the propagation direction of the wave

Canine and human gastrointestinal stromal tumors display similar mutations in c-KIT exon 11

<p>Abstract</p> <p>Background</p> <p>Gastrointestinal stromal tumors (GISTs) are common mesenchymal neoplasms in the gastrointestinal tract of humans and dogs. Little is known about the pathogenesis of these tumors. This study evaluated the role of <it>c-KIT </it>in canine GISTs; specifically, we investigated activating mutations in exons 8, 9, 11, 13, and 17 of <it>c-KIT </it>and exons 12, 14, and 18 of platelet-derived growth factor receptor, alpha polypeptide (<it>PDGFRA</it>), all of which have been implicated in human GISTs.</p> <p>Methods</p> <p>Seventeen canine GISTs all confirmed to be positive for KIT immunostaining were studied. Exons 8, 9, 11, 13 and 17 of <it>c-KIT </it>and exons 12, 14, and 18 of <it>PDGFRA</it>, were amplified from DNA isolated from formalin-fixed paraffin-embedded samples.</p> <p>Results</p> <p>Of these seventeen cases, six amplicons of exon 11 of <it>c-KIT </it>showed aberrant bands on gel electrophoresis. Sequencing of these amplicons revealed heterozygous in-frame deletions in six cases. The mutations include two different but overlapping six base pair deletions. Exons 8, 9, 13, and 17 of <it>c-KIT </it>and exons 12, 14, and 18 of <it>PDGFRA </it>had no abnormalities detected by electrophoresis and sequencing did not reveal any mutations, other than synonymous single nucleotide polymorphisms (SNPs) found in exon 11 of <it>c-KIT </it>and exons 12 and 14 of <it>PDGFRA</it>.</p> <p>Conclusions</p> <p>The deletion mutations detected in canine GISTs are similar to those previously found in the juxtamembrane domain of <it>c-KIT </it>in canine cutaneous mast cell tumors in our laboratory as well as to those reported in human GISTs. Interestingly, none of the other <it>c-KIT </it>or <it>PDGFRA </it>exons showed any abnormalities in our cases. This finding underlines the critical importance of <it>c-KIT </it>in the pathophysiology of canine GISTs. The expression of KIT and the identification of these activating mutations in <it>c-KIT </it>implicate KIT in the pathogenesis of these tumors. Our results indicate that mutations in <it>c-KIT </it>may be of prognostic significance and that targeting KIT may be a rational approach to treatment of these malignant tumors. This study further demonstrates that spontaneously occurring canine GISTs share molecular features with human GISTs and are an appropriate model for human GISTs.</p

Mobilise-D insights to estimate real-world walking speed in multiple conditions with a wearable device

This study aimed to validate a wearable device’s walking speed estimation pipeline, considering complexity, speed, and walking bout duration. The goal was to provide recommendations on the use of wearable devices for real-world mobility analysis. Participants with Parkinson’s Disease, Multiple Sclerosis, Proximal Femoral Fracture, Chronic Obstructive Pulmonary Disease, Congestive Heart Failure, and healthy older adults (n = 97) were monitored in the laboratory and the real-world (2.5 h), using a lower back wearable device. Two walking speed estimation pipelines were validated across 4408/1298 (2.5 h/laboratory) detected walking bouts, compared to 4620/1365 bouts detected by a multi-sensor reference system. In the laboratory, the mean absolute error (MAE) and mean relative error (MRE) for walking speed estimation ranged from 0.06 to 0.12 m/s and − 2.1 to 14.4%, with ICCs (Intraclass correlation coefficients) between good (0.79) and excellent (0.91). Real-world MAE ranged from 0.09 to 0.13, MARE from 1.3 to 22.7%, with ICCs indicating moderate (0.57) to good (0.88) agreement. Lower errors were observed for cohorts without major gait impairments, less complex tasks, and longer walking bouts. The analytical pipelines demonstrated moderate to good accuracy in estimating walking speed. Accuracy depended on confounding factors, emphasizing the need for robust technical validation before clinical application. Trial registration: ISRCTN – 12246987

Structural Integration of a Ku-band SatCom Antenna into Novel Fuselage Panel

This paper addresses the structural integration of a Ku-band SATCOM antenna in the fuselage of an aircraft. The phased array antenna consists of 25 antenna tiles that are integrated in an orthogrid fuselage panel. The specific electromagnetic aspects of the antenna integration will be discussed in this paper; this concerns the lightning protection of the antenna tiles and the electromagnetic interaction of the CFRP orthogrid and GFRP fuselage skin with the array antenna. The structural properties and thermal management of the antenna will be discussed in separate papers [1,2,3]

The New Freezing of Gait Questionnaire: Unsuitable as an Outcome in Clinical Trials?

Contains fulltext : 218916.pdf (Publisher’s version ) (Closed access)Background: Freezing of gait (FOG) is a common gait deficit in Parkinson's disease. The New Freezing of Gait Questionnaire (NFOG-Q) is a widely used and valid tool to quantify freezing of gait severity. However, its test-retest reliability and minimal detectable change remain unknown. Objective: To determine the test-retest reliability and responsiveness of the NFOG-Q. Methods: Two groups of freezers, involved in 2 previous rehabilitation trials, completed the NFOG-Q at 2 time points (T1 and T2), separated by a 6-week control period without active intervention. Sample 1 (N = 57) was measured in ON and sample 2 (N = 14) in OFF. We calculated various reliability statistics for the NFOG-Q scores between T1 and T2 as well as correlation coefficients with clinical descriptors to explain the variability between time points. Results: In sample 1 the NFOG-Q showed modest reliability (intraclass correlation coefficient = 0.68 [0.52-0.80]) without differences between T1 and T2. However, a minimal detectable change of 9.95 (7.90-12.27) points emerged for the total score (range 28 points, relative minimal detectable change of 35.5%). Sample 2 showed largely similar results. We found no associations between cognitive-related or disease severity-related outcomes and variability in NFOG-Q scores. Conclusions: We conclude that the NFOG-Q is insufficiently reliable or responsive to detect small effect sizes, as changes need to go beyond 35% to surpass measurement error. Therefore, we warrant caution in using the NFOG-Q as a primary outcome in clinical trials. These results emphasize the need for robust and objective freezing of gait outcome measures

Development of an integrated photonic beamformer for electronically-steered Ku-band phased array antenna

Currently an integrated photonic beamformer for electronically-steered Ku-band phased array antenna (PAA) system for satellite communications is being developed within a Dutch Point One R&D Innovation Project “Broadband Satellite Communication Services on High-Speed Transport Vehicles”, targeting instantaneous reception of the full Ku-band (10.7-12.75 GHz), squint-free and seamless beam steering, and polarization agility. The use of integrated photonic beamformer enables an antenna system with multi-gigahertz instantaneous bandwidth, compact form factor, light weight, and large beam scanning range, which are challenging requirements for beamformers using only electronics-based RF technologies. An important aspect tackled in this project is to reduce the system cost such that it is commercially suitable for civil purposes in mobile satellite communications, particularly in aeronautic/avionic satellite communications where a low profile and light weight are essential requirements for the antenna system

Dual-frequency phased array antennas with optical beamforming for airborne satellite communication

For enhanced communication on board of aircraft, novel antenna systems with broadband satellite-based capabilities are required. So far existing L-band satellite based systems for communications are used primarily for passenger application (APC) or administrative communications (AAC); initially analogue voice and now data are tending to evolve towards broadband digital applications. Many studies are going on worldwide to employ Ku-band TV geostationary satellites for communication with mobile terminals on aircraft. For a short period broadband internet was available on aircraft via Connexion by Boeing (CBB) services. Lufthansa installed the CBB system on some of their long-haul aircraft. In the EC Sixth Framework Programme ANASTASIA (Airborne New and Advanced Satellite techniques and Technologies in A System Integrated Approach) existing and planned aeronautical SATCOM services, systems and technology have been analysed. It has been concluded that for cockpit services, L-band systems (namely Inmarsat, MTSAT, Iridium and Globalstar) are clearly most suitable, whilst Ku-band systems have appeal for passenger service

Broadband optical beam forming for airborne phased array antenna

For enhanced communication on board aircraft, novel antenna systems with broadband satellite-based capabilities are required. The technology will enhance airline operations by providing in-flight connectivity for flight crew information and will bring live TV and high-speed Internet connectivity to passengers. The installation of such systems on board aircraft requires for aerodynamic reasons the development a very low-profile aircraft antenna, which can point to satellites anywhere in the upper hemisphere. Major keystones for the success of steerable low-profile antennas are multi-layer printed circuit boards (PCBs) with an array of broadband antenna elements, and compact micro-wave systems with appropriate beam steering capabilities. The present paper describes the development of a prototype 8times1 optical beam forming network using cascades of optical ring resonators as part of a breadboard Ku-band phased array antenna