Generalized Degrees of Freedom of the Symmetric Cache-Aided MISO Broadcast Channel with Partial CSIT

We consider the cache-aided MISO broadcast channel (BC) in which a multi-antenna transmitter serves $K$ single-antenna receivers, each equipped with a cache memory. The transmitter has access to partial knowledge of the channel state information. For a symmetric setting, in terms of channel strength levels, partial channel knowledge levels and cache sizes, we characterize the generalized degrees of freedom (GDoF) up to a constant multiplicative factor. The achievability scheme exploits the interplay between spatial multiplexing gains and coded-multicasting gain. On the other hand, a cut-set-based argument in conjunction with a GDoF outer bound for a parallel MISO BC under channel uncertainty are used for the converse. We further show that the characterized order-optimal GDoF is also attained in a decentralized setting, where no coordination is required for content placement in the caches.Comment: first revisio

How future surgery will benefit from SARS-COV-2-related measures: a SPIGC survey conveying the perspective of Italian surgeons

COVID-19 negatively affected surgical activity, but the potential benefits resulting from adopted measures remain unclear. The aim of this study was to evaluate the change in surgical activity and potential benefit from COVID-19 measures in perspective of Italian surgeons on behalf of SPIGC. A nationwide online survey on surgical practice before, during, and after COVID-19 pandemic was conducted in March-April 2022 (NCT:05323851). Effects of COVID-19 hospital-related measures on surgical patients' management and personal professional development across surgical specialties were explored. Data on demographics, pre-operative/peri-operative/post-operative management, and professional development were collected. Outcomes were matched with the corresponding volume. Four hundred and seventy-three respondents were included in final analysis across 14 surgical specialties. Since SARS-CoV-2 pandemic, application of telematic consultations (4.1% vs. 21.6%; p < 0.0001) and diagnostic evaluations (16.4% vs. 42.2%; p < 0.0001) increased. Elective surgical activities significantly reduced and surgeons opted more frequently for conservative management with a possible indication for elective (26.3% vs. 35.7%; p < 0.0001) or urgent (20.4% vs. 38.5%; p < 0.0001) surgery. All new COVID-related measures are perceived to be maintained in the future. Surgeons' personal education online increased from 12.6% (pre-COVID) to 86.6% (post-COVID; p < 0.0001). Online educational activities are considered a beneficial effect from COVID pandemic (56.4%). COVID-19 had a great impact on surgical specialties, with significant reduction of operation volume. However, some forced changes turned out to be benefits. Isolation measures pushed the use of telemedicine and telemetric devices for outpatient practice and favored communication for educational purposes and surgeon-patient/family communication. From the Italian surgeons' perspective, COVID-related measures will continue to influence future surgical clinical practice

Fundamental limits of robust interference management: from content-oblivious to content-aware wireless networks

In this thesis we progress towards the understanding of the fundamental limits of wireless networks with partial instantaneous channel state information at the transmitter (CSIT). We first consider classical content-oblivious networks, where the edge-nodes are unaware of the kind of requested content. We study the K-user multiple-input-single-output (MISO) broadcast channel (BC), where a K-antenna transmitter serves K single-antenna users, and we characterize the optimal degrees-of-freedom (DoF) region under arbitrary CSIT levels for the users. We then study the overloaded MISO BC with two groups of CSIT qualities. We propose a transmission scheme where no CSIT codewords are superimposed on top of spatially-multiplexed codewords. We show that the developed strategy outperforms the existing schemes and achieves the entire DoF region. Next, we move from content-oblivious networks to content-aware networks, where the edge-nodes can predict the most popular content. We first consider the K-user cache-aided MISO BC, where users are equipped with a cache memory. For a symmetric setting, in terms of channel strength levels, partial channel knowledge levels and cache sizes, we characterize the sum-generalized-degrees-of-freedom (sum-GDoF) up to a constant multiplicative factor of 12. We further show that the characterized order-optimal sum-GDoF is also attained in a decentralized setting, where no coordination is required for content placement in the caches. We then study the cache-aided interference channel, where an arbitrary number of cache-equipped transmitters serve an arbitrary number of cache-equipped receivers. Transmitters communicate with receivers over two heterogenous parallel subchannels: one with perfect CSIT, and the other with no CSIT. Under the assumptions of uncoded placement and separable one-shot linear delivery over the two sub-channels, we characterize the optimal sum-DoF to within a constant multiplicative factor of 2. We extend the result to decentralized setting, and we characterize the optimal one-shot linear sum-DoF to within a factor of 3.Open Acces

Optimal DoF region of the K-User MISO BC with Partial CSIT

We consider the K-User Multiple-Input-Single-Output (MISO) Broadcast Channel (BC) where the transmitter, equipped with M antennas, serves K users, with K ≤ M. The transmitter has access to a partial channel state information of the users. This is modelled by letting the variance of the Channel State Information at the Transmitter (CSIT) error of user i scale as O(P −α i) for the Signal-to-Noise Ratio (SNR) P and some constant αi ≥ 0. In this work we derive the optimal Degrees-of-Freedom (DoF) region in such setting

Pathological response on surgical samples is an independent prognostic variable for patients with Stage Ib2-IIb cervical cancer treated with neoadjuvant chemotherapy and radical hysterectomy: an Italian multicenter retrospective study (CTF Study).

Abstract OBJECTIVES: The purpose of this retrospective multicenter study was to correlate patterns of recurrences and clinical outcome of cervical cancer patients who underwent neoadjuvant chemotherapy [NACT] to surgery. METHODS: This study was conducted on 333 patients with FIGO stage Ib2-IIb cervical cancer who underwent NACT to surgery with pelvic lymphadenectomy. The median follow-up was 66.5 months (range, 8-212 months). Overall optimal response rate was the sum of complete and optimal partial response rates. RESULTS: An overall optimal response was obtained in 64 patients (19.2%). As for the 220 sub-optimal responders (66.1%), 127 patients had negative nodes and negative parametria and/or surgical margins, 75 patients had positive nodes with positive or negative parametria and/or surgical margins, and 18 patients had positive parametria and/or surgical margins with negative nodes. At the time of the present analysis, 79 (23.7%) of the 333 patients had a recurrence after a median time of 14.9 months (range, 4.5-123 months). Recurrent disease was pelvic in 50 (63.3%), extra-pelvic in 22 (27.9%), and both in 7 (8.8%). On multivariate analysis, pathological response to NACT was an independent prognostic variable for recurrence-free and overall survival. Patients who did not achieve an overall optimal response had a 2.757-fold higher risk of recurrence and a 5.413-fold higher risk of death than those who obtained an overall optimal response. CONCLUSIONS: Results appear to suggest that the chemo-surgical approach is an effective therapeutic option for patients with stage Ib2-IIb cervical cancer and that pathological response to NACT is the strongest prognostic factor for the outcome. © 2013. Published by Elsevier Inc. All rights reserved