265 research outputs found
Linear approximation of CPM signals for a reduced-complexity, multi-mode telemetry transmitter
In space applications, hardware (HW) implementation is made more expensive
not only by the levels of performance required, but also by complex and
rigorous HW qualification tests. Reducing qualification cost and time is thus a
key design requirement. In this paper, a new versatile transmitter is proposed
for space telemetry, capable of soft-switching across different linear and
continuous phase modulation schemes while maintaining the same hardware
structure. This permits a single HW qualification to ``cover'' diverse uses of
the same hardware, and thus avoid re-qualification in case of configuration
changes. The envisaged solution foresees the use of a single filter, suitable
not only for linear modulations such as M-QAM, but also for continuous phase
modulation methods. At this stage, we focus on pulse code modulation/frequency
modulation (PCM/FM), for which we propose a minimum mean square error (MMSE)
algorithm. The proposed algorithm, which adds to the system flexibility and
effectiveness, may use a single first filter based on Laurent decomposition for
initialization, if needed. Performances are assessed using the mean square
error (MSE) measure between the proposed MMSE-modulated signal and the
completely modulated signal. Simulation results confirm that the proposed
algorithm leads to MSE values that are lower than the case of Laurent
decomposition using the first component only.Comment: to be published in the IEEE ICC 2023 Conference Proceedings: SAC
Satellite and Space Communications Trac
HySenS data exploitation for urban land cover analysis
This paper addresses the use of HySenS airborne hyperspectral data for environmental urban monitoring. It is known that hyperspectral data can help to characterize some of the relations between soil composition, vegetation characteristics, and natural/artificial materials in urbanized areas. During the project we collected DAIS and ROSIS data over the urban test area of Pavia, Northern Italy, though due to a late delivery of ROSIS data only DAIS data was used in this work. Here we show results referring to an accurate characterization and classification of land cover/use, using different supervised approaches, exploiting spectral as well as spatial information. We demonstrate the possibility to extract from the hyperspectral data information which is very useful for environmental characterization of urban areas
Supervised / unsupervised change detection
The aim of this deliverable is to provide an overview of the state of the art in change detection techniques and a critique of what could be programmed to derive SENSUM products. It is the product of the collaboration between UCAM and EUCENTRE. The document includes as a necessary requirement a discussion about a proposed technique for co-registration. Since change detection techniques require an assessment of a series of images and the basic process involves comparing and contrasting the similarities and differences to essentially spot changes, co-registration is the first step. This ensures that the user is comparing like for like. The developed programs would then be used on remotely sensed images for applications in vulnerability assessment and post-disaster recovery assessment and monitoring. One key criterion is to develop semi-automated and automated techniques.
A series of available techniques are presented along with the advantages and disadvantages of each method. The descriptions of the implemented methods are included in the deliverable D2.7 ”Software Package SW2.3”.
In reviewing the available change detection techniques, the focus was on ways to exploit medium resolution imagery such as Landsat due to its free-to-use license and since there is a rich historical coverage arising from this satellite series.
Regarding the change detection techniques with high resolution images, this was also examined and a recovery specific change detection index is discussed in the report
The IEEE GRSS standardized remote sensing data website: A step towards "science 2.0" in remote sensing
The issue of homogeneity in performance assessment of proposed algorithms for information extraction is generally perceived also in the Earth Observation (EO) domain. Different authors propose different datasets to test their developed algorithms and to the reader it is frequently difficult to assess which is better for his/her specific application, given the wide variability in test sets that makes pure comparison of e.g. accuracy values less meaningful than one would desire. With our work, we gave a modest contribution to ease the problem by making it possible to automatically distribute a limited set of possible "standard" open datasets, together with some ground truth info, and automatically assess processing results provided by the users
Dense Refinement Residual Network for Road Extraction From Aerial Imagery Data
Extraction of roads from high-resolution aerial images with a high degree of accuracy is a prerequisite in various applications. In aerial images, road pixels and background pixels are generally in the ratio of ones-to-tens, which implies a class imbalance problem. Existing semantic segmentation architectures generally do well in road-dominated cases but fail in background-dominated scenarios. This paper proposes a dense refinement residual network (DRR Net) for semantic segmentation of aerial imagery data. The proposed semantic segmentation architecture is composed of multiple DRR modules for the extraction of diversified roads alleviating the class imbalance problem. Each module of the proposed architecture utilizes dense convolutions at various scales only in the encoder for feature learning. Residual connections in each module of the proposed architecture provide the guided learning path by propagating the combined features to subsequent DRR modules. Segmentation maps undergo various levels of refinement based on the number of DRR modules utilized in the architecture. To emphasize more on small object instances, the proposed architecture has been trained with a composite loss function. The qualitative and quantitative results are reported by utilizing the Massachusetts roads dataset. The experimental results report that the proposed architecture provides better results as compared to other recent architectures
HySenS data exploitation for urban land cover analysis
This paper addresses the use of HySenS airborne hyperspectral data for environmental urban monitoring. It is known that hyperspectral data can help to characterize some of the relations between soil composition, vegetation characteristics, and natural/artificial materials in urbanized areas. During the project we collected DAIS and ROSIS data over the urban test area of Pavia, Northern Italy, though due to a late delivery of ROSIS data only DAIS data was used in this work. Here we show results referring to an accurate characterization and classification of land cover/use, using different supervised approaches, exploiting spectral as well as spatial information. We demonstrate the possibility to extract from the hyperspectral data information which is very useful for environmental characterization of urban areas
Synthesis and reactivity of cytotoxic platinum(II) complexes of bidentate oximes: a step towards the functionalization of bioactive complexes
Two new platinum(II) complexes bearing triphenylphosphine and bidentate oxime ligands [Pt(Cl)(PPh3){(Îş2-N,O)-(1{C(R)=N(OH)-2(O)C10H6})}] (R = H, Me) were synthesized in good yields from trans-[PtCl(ÎĽ-Cl)(PPh3)]2. The structure of
[Pt(Cl)(PPh3){(Îş2-N,O)-(1{CH=N(OH)-2(O)C10H6})}] was determined by single-crystal X-ray diffraction. Both complexes showed good antiproliferative properties in vitro against HeLa, A2780, and A2780cis cancer cell lines. They reacted cleanly with
alkylating agents in the presence of aqueous bases under phase-transfer catalysis conditions to afford the corresponding O-alkylation products [Pt(Cl)(PPh3){(κ2-N,O)-(1{HC=N(OR′)-2(O)C10H6})}] [R′ = CH2CH2Cl, CH2Ph, (CH2)4Br] in good yields
Characteristics and patterns of care of endometrial cancer before and during COVID-19 pandemic
Objective: Coronavirus disease 2019 (COVID-19) outbreak has correlated with the disruption of screening activities and diagnostic assessments. Endometrial cancer (EC) is one of the most common gynecological malignancies and it is often detected at an early stage, because it frequently produces symptoms. Here, we aim to investigate the impact of COVID-19 outbreak on patterns of presentation and treatment of EC patients. Methods: This is a retrospective study involving 54 centers in Italy. We evaluated patterns of presentation and treatment of EC patients before (period 1: March 1, 2019 to February 29, 2020) and during (period 2: April 1, 2020 to March 31, 2021) the COVID-19 outbreak. Results: Medical records of 5,164 EC patients have been retrieved: 2,718 and 2,446 women treated in period 1 and period 2, respectively. Surgery was the mainstay of treatment in both periods (p=0.356). Nodal assessment was omitted in 689 (27.3%) and 484 (21.2%) patients treated in period 1 and 2, respectively (p<0.001). While, the prevalence of patients undergoing sentinel node mapping (with or without backup lymphadenectomy) has increased during the COVID-19 pandemic (46.7% in period 1 vs. 52.8% in period 2; p<0.001). Overall, 1,280 (50.4%) and 1,021 (44.7%) patients had no adjuvant therapy in period 1 and 2, respectively (p<0.001). Adjuvant therapy use has increased during COVID-19 pandemic (p<0.001). Conclusion: Our data suggest that the COVID-19 pandemic had a significant impact on the characteristics and patterns of care of EC patients. These findings highlight the need to implement healthcare services during the pandemic
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