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Abstract The differential privacy (DP) literature often centers on meeting privacy constraints by introducing noise to the query, typically using a pre-specified parametric distribution model with one or two degrees of freedom. However, this emphasis tends to neglect the crucial considerations of response accuracy and utility, especially in the context of categorical or discrete numerical database queries, where the parameters defining the noise distribution are finite and could be chosen optimally. This paper addresses this gap by introducing a novel framework for designing an optimal noise probability mass function (PMF) tailored to discrete and finite query sets. Our approach considers the modulo summation of random noise as the DP mechanism, aiming to present a tractable solution that not only satisfies privacy constraints but also minimizes query distortion. Unlike existing approaches focused solely on meeting privacy constraints, our framework seeks to optimize the noise distribution under an arbitrary $$(\epsilon , \delta )$$ ( ϵ , δ ) constraint, thereby enhancing the accuracy and utility of the response. We demonstrate that the optimal PMF can be obtained through solving a mixed-integer linear program. Additionally, closed-form solutions for the optimal PMF are provided, minimizing the probability of error for two specific cases. Numerical experiments highlight the superior performance of our proposed optimal mechanisms compared to state-of-the-art methods. This paper contributes to the DP literature by presenting a clear and systematic approach to designing noise mechanisms that not only satisfy privacy requirements but also optimize query distortion. The framework introduced here opens avenues for improved privacy-preserving database queries, offering significant enhancements in response accuracy and utility.

Abstract Fast‐acting smart inverters that utilize preset operating conditions to determine real and reactive power injection/consumption can create voltage instabilities (over‐voltage, voltage oscillations and more) in an electrical distribution network if set‐points are not properly configured. In this work, linear distribution power flow equations and droop‐based Volt–Var and Volt–Watt control curves are used to analytically derive a stability criterion using Lyapunov analysis that includes the network operating condition. The methodology is generally applicable for control curves that can be represented as Lipschitz functions. The derived Lipschitz constants account for smart inverter hardware limitations for reactive power generation. A local policy is derived from the stability criterion that allows inverters to adapt their control curves by monitoring only local voltage, thus avoiding centralized control or information sharing with other inverters. The criterion is independent of the internal time‐delays of smart inverters. Simulation results for inverters with and without the proposed stabilization technique demonstrate how smart inverters can mitigate voltage oscillations locally and mitigate real and reactive power flow disturbances at the substation under multiple scenarios. The study concludes with illustrations of how the control policy can dampen oscillations caused by solar intermittency and cyberattacks.

The efficacy of cardiac rehabilitation in heart-failure patients who received a left-ventricular assist device (LVAD) instead of heart transplantation (HTx) is still unclear. This study aims to evaluate whether cardiac rehabilitation is beneficial in LVAD as HTx patients in the short term and whether its effects in LVAD patients persist over time. Twenty-five LVAD patients were evaluated by functional and psychological tests at admission (T0) and discharge (T1) of a 4-week inpatient structured rehabilitation program, and follow-ups 3 (T2), 6 (T3), and 12 months (T4) after discharge. Twenty-five matched HTx patients were also studied from T0 to T1 to compare the improvements in the six-minute walk test (6MWT). The quality-of-life scores substantially improved in LVAD patients and the 6MWT showed the same functional recovery as in HTx patients from T0 to T1. After T1, numerous LVAD patients withdrew from the study. However, the 6MWT outcome increased further from T1 to T3, with a positive trend during the follow-ups. Hemoglobin and the ventilatory performance increased, and the psychological perception of heart-failure symptoms and pain further improved at T2. In conclusion, exercise-based rehabilitation programs provide similar beneficial effects in LVAD and HTx patients, without deterioration in LVAD patients up to 12 months after discharge.

Existing radio access networks (RANs) allow only for very limited sharing of the communication and computation resources among wireless operators and heterogeneous wireless technologies. We introduce the LayBack architecture to facilitate communication and computation resource sharing among different wireless operators and technologies. LayBack organizes the RAN communication and multiaccess edge computing (MEC) resources into layers, including a devices layer, a radio node (enhanced Node B and access point) layer, and a gateway layer. LayBack positions the coordination point between the different operators and technologies just behind the gateways and thus consistently decouples the fronthaul from the backhaul. The coordination point is implemented through a software defined networking (SDN) switching layer that connects the gateways to the backhaul (core) network layer. A unifying SDN orchestrator implements an SDN-based management framework that centrally manages the fronthaul and backhaul communication and computation resources and coordinates the cooperation between different wireless operators and technologies. We illustrate the capabilities of the introduced LayBack architecture and SDN-based management framework through a case study on a novel fluid cloud RAN (CRAN) function split. The fluid CRAN function split partitions the RAN functions into function blocks that are flexibly assigned to MEC nodes, effectively implementing the RAN functions through network function virtualization. We find that for non-uniform call arrivals, the computation of the function blocks with resource sharing among operators increases a revenue rate measure by more than 25% compared to the conventional CRAN where each operator utilizes only its own resources.

Background: ST elevation myocardial infarction (STEMI) in old and old-old patients presents several peculiarities in natural history, delay of hospitalization and response to treatment. Aim of this retrospective case control study was to determine presentation, complications and management of elderly patients with STEMI compared to a younger population. Methods: 462 patients (205 M and 257 F) aged ≥75 years, hospitalized in CCU between 1999 and 2003 for STEMI, were valuated. The control group consisted of 490 consecutive patients (268 M and 222 F) aged 50-70 years. Attention was focused on clinical presentation, complications, management and outcome in elderly compared with younger patients. Results: The mean interval between the onset of symptoms and the arrive in CCU was of 9 hour in the elderly compared to 4,5 hour in the control. Chest pain was less frequent (50% vs 90%) in the elderly; the prevalence of dyspnoea and neurological symptoms was higher in patients >75 years (30% vs 15% and 25% vs 10%). In the elderly, previous angina and AMI, cerebral and peripheral vascular diseases, peripheral and renal failure were frequent. Early severe complications prevailed in the elderly. Thrombolysis was performed only in 39% of the elderly compared to 65% of the control. Significantly higher was cerebral haemorrhage after thrombolysis (4,9% vs 1,8%). Comparable were the mayor extra cranial bleedings. Primary or facilitated PTCA was performed in few patients in the last year. Two weeks mortality was 20%, compared to 6,5% in the control group. Conclusion: The patientes >75 years with STEMI were hospitalized later, had atypical presentation with less chest pain and more cardiac failure, were less likely to receive thrombolysis, had more complications and more cerebral bleedings. Elderly had more associated diseases and in-hospital mortality was higher.

Background: The quantity and intensity of physical activity required for the primary prevention of coronary heart disease remain unclear. Therefore, we examined the association between physical activity and coronary risk. Methods: We studied 100 patients with chest pain, 78 men and 22 women, not older than 65 years, admitted to a coronary care unit. Patients were subdivided in 3 groups: the first group included patients with acute myocardial infarction, the second group included patients with chronic heart disease, the third included patients with non-ischemic chest-pain. A questionnaire on daily physical activity was filled by each patient. Results: A significantly higher percentage of patients with myocardial infarction and coronary heart disease had a sedentary life style compared to patients of the third group. Compared with subjects without heart disease, a significantly higher percentage of patients of the first and second group covered a daily average distance shorter than 500 meters, while a significantly inferior percentage covered a distance longer than 1 Km every day. A significantly lower percentage of patients with coronary heart disease practised sport compared with the third group. At the time of hospitalization a very small percentage of coronary heart disease patients still practised sport. Conclusions: The association between physical activity and reduced coronary risk is clear; in order to obtain benefits it is sufficient just walking every day. Regarding physical activity, continuity is important: patients, who practised sport only in juvenile age, breaking off when older, may lose the obtained advantages.

Public power system test cases that are of high quality benefit the power systems research community with expanded resources for testing, demonstrating, and cross-validating new innovations. Building synthetic grid models for this purpose is a relatively new problem, for which a challenge is to show that created cases are sufficiently realistic. This paper puts forth a validation process based on a set of metrics observed from actual power system cases. These metrics follow the structure, proportions, and parameters of key power system elements, which can be used in assessing and validating the quality of synthetic power grids. Though wide diversity exists in the characteristics of power systems, the paper focuses on an initial set of common quantitative metrics to capture the distribution of typical values from real power systems. The process is applied to two new public test cases, which are shown to meet the criteria specified in the metrics of this paper.