| 1. |
- Benkert, P., et al.
(author)
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Serum neurofilament light chain for individual prognostication of disease activity in people with multiple sclerosis: a retrospective modelling and validation study
- 2022
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In: The Lancet Neurology. - 1474-4422 .- 1474-4465. ; 21:3, s. 246-257
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Journal article (peer-reviewed)abstract
- Background: Serum neurofilament light chain (sNfL) is a biomarker of neuronal damage that is used not only to monitor disease activity and response to drugs and to prognosticate disease course in people with multiple sclerosis on the group level. The absence of representative reference values to correct for physiological age-dependent increases in sNfL has limited the diagnostic use of this biomarker at an individual level. We aimed to assess the applicability of sNfL for identification of people at risk for future disease activity by establishing a reference database to derive reference values corrected for age and body-mass index (BMI). Furthermore, we used the reference database to test the suitability of sNfL as an endpoint for group-level comparison of effectiveness across disease-modifying therapies. Methods: For derivation of a reference database of sNfL values, a control group was created, comprising participants with no evidence of CNS disease taking part in four cohort studies in Europe and North America. We modelled the distribution of sNfL concentrations in function of physiological age-related increase and BMI-dependent modulation, to derive percentile and Z score values from this reference database, via a generalised additive model for location, scale, and shape. We tested the reference database in participants with multiple sclerosis in the Swiss Multiple Sclerosis Cohort (SMSC). We compared the association of sNfL Z scores with clinical and MRI characteristics recorded longitudinally to ascertain their respective disease prognostic capacity. We validated these findings in an independent sample of individuals with multiple sclerosis who were followed up in the Swedish Multiple Sclerosis registry. Findings: We obtained 10 133 blood samples from 5390 people (median samples per patient 1 [IQR 1–2] in the control group). In the control group, sNfL concentrations rose exponentially with age and at a steeper increased rate after approximately 50 years of age. We obtained 7769 samples from 1313 people (median samples per person 6·0 [IQR 3·0–8·0]). In people with multiple sclerosis from the SMSC, sNfL percentiles and Z scores indicated a gradually increased risk for future acute (eg, relapse and lesion formation) and chronic (disability worsening) disease activity. A sNfL Z score above 1·5 was associated with an increased risk of future clinical or MRI disease activity in all people with multiple sclerosis (odds ratio 3·15, 95% CI 2·35–4·23; p<0·0001) and in people considered stable with no evidence of disease activity (2·66, 1·08–6·55; p=0·034). Increased Z scores outperformed absolute raw sNfL cutoff values for diagnostic accuracy. At the group level, the longitudinal course of sNfL Z score values in people with multiple sclerosis from the SMSC decreased to those seen in the control group with use of monoclonal antibodies (ie, alemtuzumab, natalizumab, ocrelizumab, and rituximab) and, to a lesser extent, oral therapies (ie, dimethyl fumarate, fingolimod, siponimod, and teriflunomide). However, longitudinal sNfL Z scores remained elevated with platform compounds (interferons and glatiramer acetate; p<0·0001 for the interaction term between treatment category and treatment duration). Results were fully supported in the validation cohort (n=4341) from the Swedish Multiple Sclerosis registry. Interpretation: The use of sNfL percentiles and Z scores allows for identification of individual people with multiple sclerosis at risk for a detrimental disease course and suboptimal therapy response beyond clinical and MRI measures, specifically in people with disease activity-free status. Additionally, sNfL might be used as an endpoint for comparing effectiveness across drug classes in pragmatic trials. Funding: Swiss National Science Foundation, Progressive Multiple Sclerosis Alliance, Biogen, Celgene, Novartis, Roche. © 2022 Elsevier Ltd
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| 2. |
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| 4. |
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| 5. |
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| 6. |
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| 7. |
- Meier, S, et al.
(author)
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Serum Glial Fibrillary Acidic Protein Compared With Neurofilament Light Chain as a Biomarker for Disease Progression in Multiple Sclerosis
- 2023
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In: JAMA neurology. - : American Medical Association (AMA). - 2168-6157 .- 2168-6149. ; 80:3, s. 287-297
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Journal article (peer-reviewed)abstract
- There is a lack of validated biomarkers for disability progression independent of relapse activity (PIRA) in multiple sclerosis (MS).ObjectiveTo determine how serum glial fibrillary acidic protein (sGFAP) and serum neurofilament light chain (sNfL) correlate with features of disease progression vs acute focal inflammation in MS and how they can prognosticate disease progression.Design, Setting, and ParticipantsData were acquired in the longitudinal Swiss MS cohort (SMSC; a consortium of tertiary referral hospitals) from January 1, 2012, to October 20, 2022. The SMSC is a prospective, multicenter study performed in 8 centers in Switzerland. For this nested study, participants had to meet the following inclusion criteria: cohort 1, patients with MS and either stable or worsening disability and similar baseline Expanded Disability Status Scale scores with no relapses during the entire follow-up; and cohort 2, all SMSC study patients who had initiated and continued B-cell–depleting treatment (ie, ocrelizumab or rituximab).ExposuresPatients received standard immunotherapies or were untreated.Main Outcomes and MeasuresIn cohort 1, sGFAP and sNfL levels were measured longitudinally using Simoa assays. Healthy control samples served as the reference. In cohort 2, sGFAP and sNfL levels were determined cross-sectionally.ResultsThis study included a total of 355 patients (103 [29.0%] in cohort 1: median [IQR] age, 42.1 [33.2-47.6] years; 73 female patients [70.9%]; and 252 [71.0%] in cohort 2: median [IQR] age, 44.3 [33.3-54.7] years; 156 female patients [61.9%]) and 259 healthy controls with a median [IQR] age of 44.3 [36.3-52.3] years and 177 female individuals (68.3%). sGFAP levels in controls increased as a function of age (1.5% per year; P &lt; .001), were inversely correlated with BMI (−1.1% per BMI unit; P = .01), and were 14.9% higher in women than in men (P = .004). In cohort 1, patients with worsening progressive MS showed 50.9% higher sGFAP levels compared with those with stable MS after additional sNfL adjustment, whereas the 25% increase of sNfL disappeared after additional sGFAP adjustment. Higher sGFAP at baseline was associated with accelerated gray matter brain volume loss (per doubling: 0.24% per year; P &lt; .001) but not white matter loss. sGFAP levels remained unchanged during disease exacerbations vs remission phases. In cohort 2, median (IQR) sGFAP z scores were higher in patients developing future confirmed disability worsening compared with those with stable disability (1.94 [0.36-2.23] vs 0.71 [−0.13 to 1.73]; P = .002); this was not significant for sNfL. However, the combined elevation of z scores of both biomarkers resulted in a 4- to 5-fold increased risk of confirmed disability worsening (hazard ratio [HR], 4.09; 95% CI, 2.04-8.18; P &lt; .001) and PIRA (HR, 4.71; 95% CI, 2.05-9.77; P &lt; .001).Conclusions and RelevanceResults of this cohort study suggest that sGFAP is a prognostic biomarker for future PIRA and revealed its complementary potential next to sNfL. sGFAP may serve as a useful biomarker for disease progression in MS in individual patient management and drug development.
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| 8. |
- Bissell, Malenka M., et al.
(author)
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4D Flow cardiovascular magnetic resonance consensus statement : 2023 update
- 2023
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In: Journal of Cardiovascular Magnetic Resonance. - : BMC. - 1097-6647 .- 1532-429X. ; 25:1
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Research review (peer-reviewed)abstract
- Hemodynamic assessment is an integral part of the diagnosis and management of cardiovascular disease. Four-dimensional cardiovascular magnetic resonance flow imaging (4D Flow CMR) allows comprehensive and accurate assessment of flow in a single acquisition. This consensus paper is an update from the 2015 ‘4D Flow CMR Consensus Statement’. We elaborate on 4D Flow CMR sequence options and imaging considerations. The document aims to assist centers starting out with 4D Flow CMR of the heart and great vessels with advice on acquisition parameters, post-processing workflows and integration into clinical practice. Furthermore, we define minimum quality assurance and validation standards for clinical centers. We also address the challenges faced in quality assurance and validation in the research setting. We also include a checklist for recommended publication standards, specifically for 4D Flow CMR. Finally, we discuss the current limitations and the future of 4D Flow CMR. This updated consensus paper will further facilitate widespread adoption of 4D Flow CMR in the clinical workflow across the globe and aid consistently high-quality publication standards.
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| 9. |
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| 10. |
- Andersson, Mattias, et al.
(author)
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Polar codes for bidirectional broadcast channels with common and confidential messages
- 2012
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In: International Symposium on Wireless Communication Systems (ISWCS), 2012. - : IEEE conference proceedings. - 9781467307604 ; , s. 1014-1018
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Conference paper (peer-reviewed)abstract
- We consider the bidirectional broadcast channel with common and confidential messages. We show that polar codes achieve the capacity of binary input symmetrical bidirectional broadcast channels with confidential messages, if one node's channel is a degraded version of the other node's channel. We also find a new bound on the cardinality of the auxiliary random variable in this setup.
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| 11. |
- Andersson, Mattias, et al.
(author)
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Polar Coding for Bidirectional Broadcast Channels with Common and Confidential Messages
- 2013
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In: IEEE Journal on Selected Areas in Communications. - 0733-8716 .- 1558-0008. ; 31:9, s. 1901-1908
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Journal article (peer-reviewed)abstract
- The integration of multiple services such as the transmission of private, common, and confidential messages at the physical layer is becoming important for future wireless networks in order to increase spectral efficiency. In this paper, bidirectional relay networks are considered, in which a relay node establishes bidirectional communication between two other nodes using a decode-and-forward protocol. In the broadcast phase, the relay transmits additional common and confidential messages, which then requires the study of the bidirectional broadcast channel (BBC) with common and confidential messages. This channel generalizes the broadcast channel with receiver side information considered by Kramer and Shamai. Low complexity polar codes are constructed that achieve the capacity region of both the degraded symmetric BBC, and the BBC with common and confidential messages. The use of polar codes allows an intuitive interpretation of how to incorporate receiver side information and secrecy constraints as different sets of frozen bits at the different receivers for an optimal code design. In order to show that the constructed codes achieve capacity, a tighter bound on the cardinality of an auxiliary random variable used in the converse is found using a method by Salehi.
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| 12. |
- Avula, Ramana R., 1993-, et al.
(author)
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Adversarial Inference Control in Cyber-Physical Systems : A Bayesian Approach With Application to Smart Meters
- 2024
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In: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 12, s. 24933-24948
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Journal article (peer-reviewed)abstract
- With the emergence of cyber-physical systems (CPSs) in utility systems like electricity, water, and gas networks, data collection has become more prevalent. While data collection in these systems has numerous advantages, it also raises concerns about privacy as it can potentially reveal sensitive information about users. To address this issue, we propose a Bayesian approach to control the adversarial inference and mitigate the physical-layer privacy problem in CPSs. Specifically, we develop a control strategy for the worst-case scenario where an adversary has perfect knowledge of the user’s control strategy. For finite state-space problems, we derive the fixed-point Bellman’s equation for an optimal stationary strategy and discuss a few practical approaches to solve it using optimization-based control design. Addressing the computational complexity, we propose a reinforcement learning approach based on the Actor-Critic architecture. To also support smart meter privacy research, we present a publicly accessible “Co-LivEn” dataset with comprehensive electrical measurements of appliances in a co-living household. Using this dataset, we benchmark the proposed reinforcement learning approach. The results demonstrate its effectiveness in reducing privacy leakage. Our work provides valuable insights and practical solutions for managing adversarial inference in cyber-physical systems, with a particular focus on enhancing privacy in smart meter applications.
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| 13. |
- Avula, Ramana R., et al.
(author)
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Adversarial Inference Control in Cyber-Physical Systems : A Bayesian Approach With Application to Smart Meters
- 2024
-
In: IEEE Access. - : Institute of Electrical and Electronics Engineers Inc.. - 2169-3536. ; 12, s. 24933-24948
-
Journal article (peer-reviewed)abstract
- With the emergence of cyber-physical systems (CPSs) in utility systems like electricity, water, and gas networks, data collection has become more prevalent. While data collection in these systems has numerous advantages, it also raises concerns about privacy as it can potentially reveal sensitive information about users. To address this issue, we propose a Bayesian approach to control the adversarial inference and mitigate the physical-layer privacy problem in CPSs. Specifically, we develop a control strategy for the worst-case scenario where an adversary has perfect knowledge of the user’s control strategy. For finite state-space problems, we derive the fixed-point Bellman’s equation for an optimal stationary strategy and discuss a few practical approaches to solve it using optimization-based control design. Addressing the computational complexity, we propose a reinforcement learning approach based on the Actor-Critic architecture. To also support smart meter privacy research, we present a publicly accessible ’Co-LivEn’ dataset with comprehensive electrical measurements of appliances in a co-living household. Using this dataset, we benchmark the proposed reinforcement learning approach. The results demonstrate its effectiveness in reducing privacy leakage. Our work provides valuable insights and practical solutions for managing adversarial inference in cyber-physical systems, with a particular focus on enhancing privacy in smart meter applications.
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| 14. |
- Avula, Ramana R., 1993-, et al.
(author)
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Design Framework for Privacy-Aware Demand-Side Management with Realistic Energy Storage Model
- 2021
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In: IEEE Transactions on Smart Grid. - : Institute of Electrical and Electronics Engineers (IEEE). - 1949-3053 .- 1949-3061. ; 12:4, s. 3503-3513
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Journal article (peer-reviewed)abstract
- Demand-side management (DSM) is a process by which the user demand patterns are modified to meet certain desired objectives. Traditionally, DSM was utility-driven, but with an increase in the integration of renewable sources and privacy-conscious consumers, it also becomes a “consumer-driven" process. Promising theoretical studies have shown that privacy can be achieved by shaping the user demand using an energy storage system (ESS). In this paper, we present a framework for utility-driven DSM while considering the user privacy and the ESS operational cost due to its energy losses and capacity degradation. We propose an ESS model using a circuit-based and data-driven approach that can be used to capture the ESS characteristics in control strategy designs. We measure privacy leakage using the Bayesian risk of a hypothesis testing adversary and present a novel recursive algorithm to compute the optimal privacy control strategy. Further, we design an energy-flow control strategy that achieves the Pareto-optimal trade-off between privacy leakage, deviation of demand from a DSM target profile, and the ESS cost. With numerical experiments using real household data and an emulated lithium-ion battery, we show that the desired level of privacy and demand shaping performance can be achieved while reducing the ESS degradation.
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| 15. |
- Avula, Ramana R., 1993-, et al.
(author)
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On design of optimal smart meter privacy control strategy against adversarial MAP detection
- 2020
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In: Proceedings of the ICASSP 2020 - 2020 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP). - Barcelona, Spain : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 5845-5849
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Conference paper (peer-reviewed)abstract
- We study the optimal control problem of the maximum a posteriori (MAP) state sequence detection of an adversary using smart meter data. The privacy leakage is measured using the Bayesian risk and the privacy-enhancing control is achieved in real-time using an energy storage system. The control strategy is designed to minimize the expected performance of a non-causal adversary at each time instant. With a discrete-state Markov model, we study two detection problems: when the adversary is unaware or aware of the control. We show that the adversary in the former case can be controlled optimally. In the latter case, where the optimal control problem is shown to be non-convex, we propose an adaptive-grid approximation algorithm to obtain a sub-optimal strategy with reduced complexity. Although this work focuses on privacy in smart meters, it can be generalized to other sensor networks.
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| 16. |
- Avula, Ramana R., 1993-, et al.
(author)
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Optimal privacy-by-design strategy for user demand shaping in smart grids
- 2020
-
In: Proceedings of the 2020 IEEE Power & Energy Society Innovative Smart Grid Technologies. - : Institute of Electrical and Electronics Engineers (IEEE).
-
Conference paper (peer-reviewed)abstract
- In this work, we propose an optimal privacy-by-design strategy using an energy storage system (ESS) that is capable of shaping the user demand to follow a time-varying target profile. In addition, we consider the ESS usage cost due to its energy losses and capacity degradation. We measure the privacy leakage in terms of the Bayesian risk. The proposed strategy is computed by solving a multi-objective optimization problem using the Markov decision process framework. With numerical simulations using real household consumption data and a lithium-ion battery model, we study the trade-off between the achievable Bayesian risk, the variations in the user demand from the target profile and the energy storage cost. The results show that by trading-off some privacy, the variations in the user demand can be reduced while improving the battery lifetime.
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| 17. |
- Avula, Ramana R., 1993-, et al.
(author)
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Privacy-Enhancing Appliance Filtering For Smart Meters
- 2022
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In: International Conference on Acoustics, Speech, and Signal Processing (ICASSP). - : Institute of Electrical and Electronics Engineers (IEEE).
-
Conference paper (peer-reviewed)abstract
- Non-intrusive load monitoring (NILM) is the process of disaggregating total electricity consumption measured by a smart meter into individual appliances’ contributions. In this paper, we present a privacy control strategy that selectively filters appliances’ consumption from the smart meter measurements to hinder NILM disaggregation performance. The privacy controller uses charging and discharging operations of an energy storage to achieve desired smart meter measurements. We model the household consumption using both additive and difference factorial hidden Markov models and design a control strategy to minimize privacy leakage measured in terms of Bayesian risk due to maximum a posteriori detection. Due to the high computational complexity of the optimal control strategy, we propose a computationally efficient sub-optimal strategy. We evaluate the proposed approaches using the ECO data set and show their privacy improvements against the Viterbi disaggregation algorithm.
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| 18. |
- Avula, Ramana R., et al.
(author)
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Privacy-preserving smart meter control strategy including energy storage losses
- 2018
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In: Proceedings - 2018 IEEE PES Innovative Smart Grid Technologies Conference Europe, ISGT-Europe 2018. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538645055
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Conference paper (peer-reviewed)abstract
- Privacy-preserving smart meter control strategies proposed in the literature so far make some ideal assumptions such as instantaneous control without delay, lossless energy storage systems etc. In this paper, we present a one-step-ahead predictive control strategy using Bayesian risk to measure and control privacy leakage with an energy storage system. The controller estimates energy state using a three-circuit energy storage model to account for steady-state energy losses. With numerical experiments, the controller is evaluated with real household consumption data using a state-of-the-art adversarial algorithm. Results show that the state estimation of the energy storage system significantly affects the controller's performance. The results also show that the privacy leakage can be effectively reduced using an energy storage system but at the expense of energy loss.
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| 19. |
- Avula, Ramana Reddy, 1993-, et al.
(author)
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Smart Meter Privacy Control Strategy Including Energy Storage Degradation
- 2019
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In: 2019 IEEE Milan PowerTech. - : IEEE.
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Conference paper (peer-reviewed)abstract
- In this paper, we present a degradation-aware privacy control strategy for smart meters by taking into account the capacity fade and energy loss of the battery, which has not been included previously. The energy management strategy is designed by minimizing the weighted sum of both privacy loss and total energy storage losses, where the weightage is set using a trade-off parameter. The privacy loss is measured in terms of Bayesian risk of an unauthorized hypothesis test. By making first-order Markov assumptions, the stochastic parameters of energy loss and capacity fade of the energy storage system are modelled using degradation maps. Using household power consumption data from the ECO dataset, the proposed control strategy is numerically evaluated for different trade-off parameters. Results show that, by including the degradation losses in the design of the privacy-enhancing control strategy, significant improvement in battery life can be achieved, in general, at the expense of some privacy loss.
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| 20. |
- Avula, Ramana Reddy, 1993-
(author)
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Towards Realistic Smart Meter Privacy against Bayesian Inference
- 2023
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Doctoral thesis (other academic/artistic)abstract
- Smart meters, now an essential component of modern power grids, allow energy providers to remotely monitor users' energy consumption in near real-time. While this technology offers numerous advantages for energy management and system efficiency, it also poses significant privacy concerns. High-resolution energy consumption data can reveal sensitive information about users' routines and activities, thus potentially jeopardizing their privacy. In particular, research has demonstrated that Bayesian inference attacks can effectively disaggregate smart meter data to deduce household appliance states and subsequently obtain sensitive user information.This thesis investigates the use of energy storage systems to protect smart meter data privacy against Bayesian inference attacks. Although several methods have been proposed in the literature that employ energy storage systems for this purpose, many rely on ideal assumptions such as lossless energy storage systems. To address this issue, a data-driven energy storage model that considers energy losses and capacity degradation has been proposed. Privacy leakage is quantified in terms of Bayesian risk, and control strategies are devised to minimize Bayesian risk while accounting for the energy storage system's operational constraints and economic implications. The findings reveal that non-idealities in energy storage systems significantly affect the privacy-preserving performance of control strategies. Moreover, incorporating degradation losses in the design of privacy-enhancing control strategies considerably improves battery life, albeit with some privacy loss.Taking into account the non-idealities of energy storage, this thesis introduces novel privacy-preserving control strategies using various adversarial models, which are classified based on their knowledge of the control system. These models include controller-aware and controller-unaware adversaries employing sequential hypothesis testing or maximum a posteriori detection. The proposed control strategies are evaluated through numerical simulations using real data and emulated energy storage systems. Additionally, the thesis provides a reference dataset of appliance power consumption, featuring detailed electrical measurements to support future smart meter privacy research. In summary, this work offers valuable insights and practical solutions for managing adversarial inference in cyber-physical systems, with potential applications extending to other sensor networks beyond smart meters.
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| 21. |
- Bao, Yicheng, et al.
(author)
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Proof-of-Concept of Polar Codes for Biometric Identification and Authentication
- 2022
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In: 2022 IEEE INTERNATIONAL WORKSHOP ON INFORMATION FORENSICS AND SECURITY (WIFS). - : Institute of Electrical and Electronics Engineers (IEEE).
-
Conference paper (peer-reviewed)abstract
- In this work, a complete biometrics identification and authentication system considered in [1] is implemented. In the considered system, polar codes are applied and binary symmetric memoryless channels are used for noisy enrollment and observation. The fundamental limits can be achieved with sufficiently long block length for iid binary source sequence. Fingerprints are used as the biometric source and an autoencoder is designed for pre-processing so that images are compressed to nearly uniformly distributed binary sequences with similar correlation and entropy properties to iid binary sequence. The identification and authentication system with generated secret key in [1] is implemented and simulated using pre-processed fingerprints as biometric source and polar code-based design. The proposed system design approach is systematic and flexible in choosing the optimal trade-off. The results show that identification error rates become smaller with longer code length and when the successive cancellation list algorithm is applied. Thus, it is shown by these first promising experiments that polar codes can be used in real identification and authentication systems.
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| 22. |
- Bilal, Ibrahim, et al.
(author)
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An Optimized Linear Scheme for Stabilization Over Multi-User Gaussian Networks
- 2013
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In: 2013 Information Theory And Applications Workshop (ITA). - New York : IEEE. - 9781467346481 ; , s. 290-297
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Conference paper (peer-reviewed)abstract
- Remote stabilization of linear dynamical systems over Gaussian networks is studied. Two linear time invariant systems (plants) with arbitrary distributed initial states are monitored by two separate sensors. The sensors communicate their measurements to two remotely situated controllers over a Gaussian interference, possibly with the assistance from a relay node. The common goal of the sensors, relay, and controllers is to stabilize the plants in mean-square sense. An optimized linear delay-free sensing and control scheme is proposed and sufficient conditions for mean-square stability are derived. These conditions reveal the relationship between plants' stability and communication channel parameters. It is shown that the proposed linear scheme can significantly outperform the existing estimation based control scheme in multi-user Gaussian networks.
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| 23. |
- Bilal, Ibrahim, et al.
(author)
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Feedback stabilization over a Gaussian interference relay channel
- 2013
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In: 2013 IEEE 14th Workshop on Signal Processing Advances in Wireless Communications, SPAWC. - : IEEE. - 9781467355773 ; , s. 560-564
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Conference paper (peer-reviewed)abstract
- A transmission scheme for mean square stabilization of two linear systems over a Gaussian interference relay channel is studied. A delay-free linear sensing and control strategy is proposed and an achievable stability region is derived. It shows that the stability region can be significantly enlarged by deploying a relay node in such a multi-user Gaussian channels. Furthermore we observe that the separation structure between estimation and control is inadequate in high interference regime.
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| 24. |
- Bilal, Ibrahim, et al.
(author)
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Managing interference for stabilization over wireless channels
- 2012
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In: Intelligent Control (ISIC), 2012 IEEE International Symposium on. - : IEEE. - 9781467345989 ; , s. 933-938
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Conference paper (peer-reviewed)abstract
- The remote stabilization of a first order linear plant over a wireless channel is studied. The plant is assumed to have an arbitrary distributed initial state and the wireless channel between the plant's sensor and the controller is modeled as a white Gaussian channel subject to an external interference signal. In order to combat the interference a dedicated sensor (relay) node is deployed adjacent to the interferer, which relays the interference information to both the plant's sensor and the controller. The sensor and the controller utilize this information to mitigate interference. We use delay-free linear sensing and control scheme in order to derive sufficient conditions for mean square stability. The achievable stability region significantly enlarges with the relay assisted interference cancelation scheme. Moreover the effect of interference can be completely eliminated if the encoder knows all the future values of the interference.
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| 25. |
- Bjelakovic, Igor, et al.
(author)
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On the strong converse for the broadcast capacity region of two-phase bidirectional relaying
- 2007
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In: Proceedings of the 2007 IEEE Information Theory Workshop on Information Theory for Wireless Networks, ITW. ; , s. 111-115
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Conference paper (peer-reviewed)abstract
- In our previous work we determined the weak capacity region for the broadcast phase of two-phase bidirectional relay channel. It turned out that the set of achievable rates obtained by optimizing over the two communication phases exceeds that obtained by using the network coding principle, i.e. by applying XOR to the decoded messages. In this paper we supplement our result by a proof of the strong converse with respect to the maximum error probability to the coding theorem for the broadcast phase. This result implies that the capacity region of that phase remains constant for a certain range of values of average error parameters [epsilon(1), epsilon(2)].
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| 26. |
- Cao, Le Phuong, et al.
(author)
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Optimal transmit strategy for MIMO channels with joint sum and per-antenna power constraints
- 2017
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In: 2017 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP). - : IEEE. - 9781509041176 ; , s. 3569-3573
-
Conference paper (peer-reviewed)abstract
- This paper studies optimal transmit strategies for multiple-input multiple-output (MIMO) Gaussian channels with joint sum and per-antenna power constraints. It is shown that if an unconstraint optimal allocation for an antenna exceeds a per-antenna power constraint, then the maximal power for this antenna is used in the constraint optimal transmit strategy. This observation is then used in an iterative algorithm to compute the optimal transmit strategy in closed-form. Finally, a numerical example is provided to illustrate the theoretical results.
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| 27. |
- Cao, Le Phuong, et al.
(author)
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Transmit Beamforming for Single-User Large-Scale MISO Systems With Sub-Connected Architecture and Power Constraints
- 2018
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In: IEEE Communications Letters. - : IEEE. - 1089-7798 .- 1558-2558. ; 22:10, s. 2096-2099
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Journal article (peer-reviewed)abstract
- This letter considers optimal transmit beamforming for a sub-connected large-scale MISO system with RF chain and per-antenna power constraints. The system is configured such that each RF chain serves a group of antennas. For the hybrid scheme, necessary and sufficient conditions to design the optimal digital and analog precoders are provided. It is shown that, in the optimum, the optimal phase shift at each antenna has to match the channel coefficient and the phase of the digital precoder. In addition, an iterative algorithm is provided to find the optimal power allocation. We study the case where the power constraint on each RF chain is smaller than the sum of the corresponding per-antenna power constraints. Then, the optimal power is allocated based on two properties: each RF chain uses full power and if the optimal power allocation of the unconstraint problem violates a per-antenna power constraint then it is optimal to allocate the maximal power for that antenna.
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| 28. |
- Cao, Phuong, et al.
(author)
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Optimal Transmission Rate for MISO Channels with Joint Sum and Per-antenna Power Constraints
- 2015
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In: IEEE International Conference on Communications (ICC), London, June 08-12, 2015. - 9781467364324 ; , s. 4727-4732
-
Conference paper (peer-reviewed)abstract
- We consider multiple-input single-output (MISO) Gaussian channels with joint sum and per-antenna power constraints. A closed-form solution of the optimal beamforming vector is derived which achieves the maximal transmission rate. The result shows that if the sum power constraint only optimal power allocation violates a per-antenna power constraint then the joint power constraint optimal power allocation is at the intersection of the sum power constraint and the per-antenna power constraints.
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| 29. |
- Cao, Phuong, et al.
(author)
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Optimal Transmit Strategies for Gaussian MISO Wiretap Channels
- 2018
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In: IEEE Transactions on Information Forensics and Security. - 1556-6013 .- 1556-6021.
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Journal article (other academic/artistic)abstract
- This paper studies the optimal tradeoff between secrecy and non-secrecy rates of the MISO wiretap channels for different power constraint settings:sum power constraint only, per-antenna power constraints only and joint sum and per-antenna power constraints. The problem is motivated by the fact thatchannel capacity and secrecy capacity are generally achieved by different transmit strategies. First, a necessary and sufficient condition to ensure a positive secrecy capacity is shown. The optimal tradeoff between secrecy rate and transmission rate is characterized by a weighted rate sum maximization problem. Since this problem is not necessarily convex, equivalent problem formulations are introduced to derive the optimal transmit strategies. Under sum power constraint only, a closed-form solution is provided. Under per-antenna power constraints, necessary conditions to find the optimal power allocation are provided. Sufficient conditions are provided for the special case of two transmit antennas. For the special case of parallel channels, the optimal transmit strategies can deduced from an equivalent point-to-point channel problem. Lastly, the theoretical results are illustrated by numerical simulations.
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| 30. |
- Cao, Phuong, et al.
(author)
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Optimal Transmit Strategies for Gaussian MISO Wiretap Channels
- 2020
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In: IEEE Transactions on Information Forensics and Security. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1556-6013 .- 1556-6021. ; 15, s. 829-838
-
Journal article (peer-reviewed)abstract
- This paper studies the optimal tradeoff between secrecy and non-secrecy rates of the MISO wiretap channels for different power constraint settings: sum power constraint only, per-antenna power constraints only, and joint sum and per-antenna power constraints. The problem is motivated by the fact that channel capacity and secrecy capacity are generally achieved by different transmit strategies. First, a necessary and sufficient condition to ensure a positive secrecy capacity is shown. The optimal tradeoff between secrecy rate and transmission rate is characterized by a weighted rate sum maximization problem. Since this problem is not necessarily convex, equivalent problem formulations are introduced to derive the optimal transmit strategies. Under sum power constraint only, a closed-form solution is provided. Under per-antenna power constraints, necessary conditions to find the optimal power allocation are derived. Sufficient conditions are provided for the special case of two transmit antennas. For the special case of aligned channels, the optimal transmit strategies can deduced from an equivalent point-to-point channel problem. Last, the theoretical results are illustrated by numerical simulations.
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| 31. |
- Cao, Phuong, et al.
(author)
-
Precoding Design for Massive MIMO Systems with Sub-connected Architecture and Per-antenna Power Constraints
- 2018
-
Conference paper (peer-reviewed)abstract
- This paper provides the necessary conditions to design precoding matrices for massive MIMO systems with a sub-connected architecture, RF power constraints and per-antenna power constraints. The system is configured such that each RFchain serves a group of antennas. The necessary condition to design the digital precoder is established based on a generalized water-filling and joint sum and per-antenna optimal power allocation solution, while the analog precoder is based on a per-antenna power allocation solution only. We study the analytically most interesting case where the power constraint on the RF chain is smaller than the sum of the corresponding per-antenna power constraints. For this, the optimal power is allocated based on two properties: Each RF chain uses full power and if the optimal power allocation of the unconstraint problem violates a per-antenna power constraint then it is optimal to allocate the maximal power for that antenna.
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| 32. |
- Cervia, Giulia, et al.
(author)
-
(epsilon, n) Fixed-Length Strong Coordination Capacity
- 2021
-
In: 2021 IEEE Information Theory Workshop (ITW). - : Institute of Electrical and Electronics Engineers (IEEE).
-
Conference paper (peer-reviewed)abstract
- This paper investigates the problem of synthesizing joint distributions in the finite-length regime. For a fixed block-length n and an upper bound on the distribution approximation epsilon, we prove a capacity result for fixed-length strong coordination. It is shown analytically that the rate conditions for the fixedlength regime are lower-bounded by the mutual information that appears in the asymptotical condition plus Q(-1) (epsilon) root V/n, where V is the channel dispersion, and Q(-1) is the inverse of the tail distribution function of the standard normal distribution. A full version of this paper is accessible at: https://arxiv.org/pdf/2101.06937.pdf
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| 33. |
- Cervia, Giulia, et al.
(author)
-
Fixed-Length Strong Coordination
- 2019
-
In: 2019 IEEE Information Theory Workshop, ITW 2019. - : Institute of Electrical and Electronics Engineers Inc.. - 9781538669006
-
Conference paper (peer-reviewed)abstract
- We consider the problem of synthesizing joint distributions of signals and actions over noisy channels in the finite length regime. For a fixed blocklength n and an upper bound on the distance ϵ, a coding scheme is proposed such that the induced joint distribution is \varepsilon-close in L1 distance to a target i.i.d. distribution. The set of achievable target distributions and rate for asymptotic strong coordination can be recovered from the main result of this paper by having n that tends to infinity.
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| 34. |
- Cervia, Giulia, et al.
(author)
-
Remote Joint Strong Coordination and Reliable Communication
- 2020
-
Conference paper (peer-reviewed)abstract
- We consider a three-node network, in which two agents wish to communicate over a noisy channel, while control- ling the distribution observed by a third external agent. We use strong coordination to constrain the distribution, and we provide a complete characterization of the “remote strong coordination and reliable communication” region.
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| 35. |
- Champati, Jaya Prakash, et al.
(author)
-
Minimum Achievable Peak Age of Information Under Service Preemptions and Request Delay
- 2021
-
In: IEEE Journal on Selected Areas in Communications. - : IEEE Communications Society. - 0733-8716 .- 1558-0008. ; 39:5, s. 1365-1379
-
Journal article (peer-reviewed)abstract
- There is a growing interest in analysing freshness of data in networked systems. Age of Information (AoI) has emerged as a relevant metric to quantify this freshness at a receiver, and minimizing this metric for different system models has received significant research attention. However, a fundamental question remains: what is the minimum achievable AoI in any single-server-single-source queuing system for a given service-time distribution? We address this question for the average peak AoI (PAoI) statistic by considering generate-at-will source model, service preemptions, and request delays. Our main result is on the characterization of the minimum achievable average PAoI, and we show that it is achieved by a fixed-threshold policy among the set of all causal policies. We use the characterization to provide necessary and sufficient condition for preemptions to be beneficial for a given service-time distribution. Our numerical results, obtained using well-known distributions, demonstrate that the heavier the tail of a distribution the higher the performance gains of using preemptions.
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| 36. |
- Champati, Jaya Prakash, et al.
(author)
-
On the Minimum Achievable Age of Information for General Service-Time Distributions
- 2020
-
In: Proceedings 39th IEEE Conference on Computer Communications, INFOCOM 2020.
-
Conference paper (peer-reviewed)abstract
- There is a growing interest in analysing the freshness of data in networked systems. Age of Information (AoI) has emerged as a popular metric to quantify this freshness at a given destination. There has been a significant research effort in optimizing this metric in communication and networking systems under different settings. In contrast to previous works, we are interested in a fundamental question, what is the minimum achievable AoI in any single-server-single-source queuing system for a given service-time distribution? To address this question, we study a problem of optimizing AoI under service preemptions. Our main result is on the characterization of the minimum achievable average peak AoI (PAoI). We obtain this result by showing that a fixed-threshold policy is optimal in the set of all randomized-threshold causal policies. We use the characterization to provide necessary and sufficient conditions for the service-time distributions under which preemptions are beneficial.
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| 37. |
- Chen, Yiqi, et al.
(author)
-
On Strong Secrecy for Multiple Access Channel with States and causal CSI
- 2023
-
In: 2023 IEEE International Symposium on Information Theory, ISIT 2023. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 2744-2749
-
Conference paper (peer-reviewed)abstract
- Strong secrecy communication over a discrete memoryless state-dependent multiple access channel (SD-MAC) with an external eavesdropper is investigated. The channel is governed by discrete memoryless and i.i.d. channel states and the channel state information (CSI) is revealed to the encoders in a causal manner. An inner bound of the capacity is provided. To establish the inner bound, we investigate coding schemes incorporating wiretap coding and secret key agreement between the sender and the legitimate receiver. Two kinds of block Markov coding schemes are studied. The first one uses backward decoding and Wyner-Ziv coding and the secret key is constructed from a lossy reproduction of the CSI. The other one is an extended version of the existing coding scheme for point-to-point wiretap channels with causal CSI. We further investigate some capacity-achieving cases for state-dependent multiple access wiretap channels (SD-MAWCs) with degraded message sets. It turns out that the two coding schemes are both optimal in these cases.
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| 38. |
- Do, Hieu T., et al.
(author)
-
Interfering Relay Channels
- 2017
-
In: Entropy. - : MDPI AG. - 1099-4300. ; 19:9
-
Journal article (peer-reviewed)abstract
- This paper introduces and studies a model in which two relay channels interfere with each other. Motivated by practical scenarios in heterogeneous wireless access networks, each relay is assumed to be connected to its intended receiver through a digital link with finite capacity. Inner and outer bounds for achievable rates are derived and shown to be tight for new discrete memoryless classes, which generalize and unify several known cases involving interference and relay channels. Capacity region and sum capacity for multiple Gaussian scenarios are also characterized to within a constant gap. The results show the optimality or near-optimality of the quantize-bin-and-forward coding scheme for practically relevant relay-interference networks, which brings important engineering insight into the design of wireless communications systems.
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| 39. |
- Do, Hieu T., et al.
(author)
-
Layered Coding for the Interference Channel With a Relay
- 2014
-
In: IEEE Transactions on Information Theory. - 0018-9448 .- 1557-9654. ; 60:10, s. 6154-6180
-
Journal article (peer-reviewed)abstract
- This paper studies and derives new results for the interference channel with a relay (ICR). Three inner bounds for the discrete memoryless ICR are proposed, based on three coding strategies that employ layered code at the relay. The first scheme is inspired by layered noisy network coding, proposed by Lim et al. for the two-way relay channel, the second and the third schemes rely on simpler encoding and decoding processes, dubbed layered quantize-forward. Performance of the proposed schemes is investigated for two classes of channels with Gaussian noise: the interference channel with in-band relay reception/out-of-band relay transmission and the interference with in-band relay reception/in-band relay transmission. For the former class of channels, it is shown that the first proposed scheme achieves the same inner bound as the generalized hash-forward scheme with incremental binning. In addition, the inner bound is within 0.5 bit of the capacity region under certain conditions on the channel parameters. For the latter class of channels, new upper bounds on sum-rate are established by extending known upper bounds for symmetric channels. The first inner bound is shown to be within 0.5 bit of the capacity region if the relay's power exceeds a certain threshold, which depends on channel parameters. Numerical examples show that the proposed schemes can achieve significantly higher sum-rates when compared with other compress-forward schemes. Analysis also reveals a tradeoff between achievable rates, coding delay, and complexity of the proposed schemes. Results in this paper provide a better understanding of coding for the ICR, in particular, they show that layered coding is a beneficial element in multiuser networks with relays.
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| 40. |
- Do, Tan Tai, et al.
(author)
-
Capacity analysis of continuous-time time-variant asynchronous uplink wideband CDMA system
- 2014
-
In: IEEE Vehicular Technology Conference. - 9781479944491 - 9781479944491
-
Conference paper (peer-reviewed)abstract
- This paper considers the capacity limit of an uplink wideband CDMA system. In order to make the studied results useful for the performance assessment of real cellular networks, various realistic assumptions are included in the problem. An equivalent discrete-time channel model is derived based on sufcient statistic for optimal decoding of transmit messages. The capacity regions are then characterized considering nite constellation and Gaussian input assumptions. For further insight, an analysis on the asymptotic capacity is considered, in which the conditions to simultaneously achieve the individual capacities are derived.
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| 41. |
- Do, Tan Tai, et al.
(author)
-
Capacity analysis of uplink WCDMA systems with imperfect channel state information
- 2015
-
In: IEEE Vehicular Technology Conference. - : IEEE. - 9781479980888
-
Conference paper (peer-reviewed)abstract
- This paper considers the capacity limit of an uplink wideband CDMA (WCDMA) system assuming imperfect channel state information at the receiver (CSIR). In order to make the studied results useful for the performance assessment of real cellular networks, various realistic assumptions are included in the problem. A discrete-time channel model is derived based on the mismatched filtering at the receiver. Capacity inner bounds are then characterized based on the discrete-time channel model considering different assumptions on decoding strategy. Numerical results are also provided to show the effect of imperfect CSIR on the capacity.
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| 42. |
- Do, Tan Tai, et al.
(author)
-
Optimal Transmission for the MIMO Bidirectional Broadcast Channel in the Wideband Regime
- 2013
-
In: IEEE Transactions on Signal Processing. - 1053-587X .- 1941-0476. ; 61:20, s. 5103-5116
-
Journal article (peer-reviewed)abstract
- This paper considers a transmit strategy for an AWGN MIMO bidirectional broadcast channel in the wideband regime. In order to characterize the boundaries of the wideband capacity and energy per bit regions, the transmit strategy at the relay is designed to maximize the weighted wideband rate sum. A closed form of the optimal transmit covariance matrix is derived, which shows that a single beam transmit strategy is optimal. The transmit strategies for some special cases are also analyzed. The fairness versus energy efficiency tradeoff is then discussed. In addition, an extension to multipair MIMO bidirectional broadcast channel is studied in which we show that serving a certain pair with full power is optimal in the sense of maximizing the achievable weighted wideband rate sum. Finally, a discussion on the conjecture of the minimum energy per bit for multi-pair systems is provided.
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| 43. |
- Do, Tan Tai, et al.
(author)
-
Uplink Waveform Channel With Imperfect Channel State Information and Finite Constellation Input
- 2017
-
In: IEEE Transactions on Wireless Communications. - : IEEE Press. - 1536-1276 .- 1558-2248. ; 16:2, s. 1107-1119
-
Journal article (peer-reviewed)abstract
- This paper investigates the capacity limit of an uplink waveform channel assuming imperfect channel state information at the receiver (CSIR). Various realistic assumptions are incorporated into the problem, which make the study valuable for performance assessment of real cellular networks to identify potentials for performance improvements in practical receiver designs. We assume that the continuous-time received signal is first discretized by mismatched filtering based on the imperfect CSIR. The resulting discrete-time signals are then decoded considering two different decoding strategies, i.e., an optimal decoding strategy based on specific statistics of channel estimation errors and a sub-optimal decoding strategy treating the estimation error signal as additive Gaussian noise. Motivated by the proposed decoding strategies, we study the performance of the decision feedback equalizer for finite constellation inputs, in which inter-stream interferences are treated either using their true statistics or as Gaussian noise. Numerical results are provided to exemplify the benefit of exploiting the knowledge on the statistics of the channel estimation errors and inter-stream interferences. Simulations also assess the effect of the CSI imperfectness on the achievable rate, which reveal that finite constellation inputs are less sensitive to the estimation accuracy than Gaussian input, especially in the high SNR regime.
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| 44. |
- Do, Tan Tai, et al.
(author)
-
Waveform domain framework for capacity analysis of uplink WCDMA systems
- 2015
-
In: EURASIP Journal on Wireless Communications and Networking. - : Springer. - 1687-1472 .- 1687-1499.
-
Journal article (peer-reviewed)abstract
- This paper investigates the capacity limit of an uplink WCDMA system considering a continuous-time waveform signal. Various realistic assumptions are incorporated into the problem, which make the study valuable for performance assessment of real cellular networks to identify potentials for performance improvements in practical receiver designs. An equivalent discrete-time channel model is derived based on sufficient statistics for optimal decoding of the transmitted messages. The capacity regions are then characterized using the equivalent channel considering both finite constellation and Gaussian distributed input signals. The capacity with sampling at the receiver is also provided to exemplify the performance loss due to a typical post-processing at the receiver. Moreover, we analyze the asymptotic capacity when the signal-to-noise ratio goes to infinity. The conditions to simultaneously achieve the individual capacities are derived, which reveal the impacts of signature waveform space, channel frequency selectivity and signal constellation on the system performance.
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| 45. |
- Fay, Dominik, et al.
(author)
-
Private Learning Via Knowledge Transfer with High-Dimensional Targets
- 2022
-
In: ICASSP 2022. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781665405409 - 9781665405416 ; , s. 3873-3877
-
Conference paper (peer-reviewed)abstract
- Preventing unintentional leakage of information about the training set has high relevance for many machine learning tasks, such as medical image segmentation. While differential privacy (DP) offers mathematically rigorous protection, the high output dimensionality of segmentation tasks prevents the direct application of state-of-the-art algorithms such as Private Aggregation of Teacher Ensembles (PATE). In order to alleviate this problem, we propose to learn dimensionality-reducing transformations to map the prediction target into a bounded lower-dimensional space to reduce the required noise level during the aggregation stage. To this end, we assess the suitability of principal component analysis (PCA) and autoencoders. We conclude that autoencoders are an effective means to reduce the noise in the target variables.
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| 46. |
- Fay, Dominik, et al.
(author)
-
Private Learning via Knowledge Transfer with High-Dimensional Targets
- 2022
-
In: 2022 IEEE INTERNATIONAL CONFERENCE ON ACOUSTICS, SPEECH AND SIGNAL PROCESSING (ICASSP). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 3873-3877
-
Conference paper (peer-reviewed)abstract
- Preventing unintentional leakage of information about the training set has high relevance for many machine learning tasks, such as medical image segmentation. While differential privacy (DP) offers mathematically rigorous protection, the high output dimensionality of segmentation tasks prevents the direct application of state-of-the-art algorithms such as Private Aggregation of Teacher Ensembles (PATE). In order to alleviate this problem, we propose to learn dimensionality-reducing transformations to map the prediction target into a bounded lower-dimensional space to reduce the required noise level during the aggregation stage. To this end, we assess the suitability of principal component analysis (PCA) and autoencoders. We conclude that autoencoders are an effective means to reduce the noise in the target variables.
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| 47. |
- Fay, Dominik
(author)
-
Towards Scalable Machine Learning with Privacy Protection
- 2023
-
Licentiate thesis (other academic/artistic)abstract
- The increasing size and complexity of datasets have accelerated the development of machine learning models and exposed the need for more scalable solutions. This thesis explores challenges associated with large-scale machine learning under data privacy constraints. With the growth of machine learning models, traditional privacy methods such as data anonymization are becoming insufficient. Thus, we delve into alternative approaches, such as differential privacy.Our research addresses the following core areas in the context of scalable privacy-preserving machine learning: First, we examine the implications of data dimensionality on privacy for the application of medical image analysis. We extend the classification algorithm Private Aggregation of Teacher Ensembles (PATE) to deal with high-dimensional labels, and demonstrate that dimensionality reduction can be used to improve privacy. Second, we consider the impact of hyperparameter selection on privacy. Here, we propose a novel adaptive technique for hyperparameter selection in differentially gradient-based optimization. Third, we investigate sampling-based solutions to scale differentially private machine learning to dataset with a large number of records. We study the privacy-enhancing properties of importance sampling, highlighting that it can outperform uniform sub-sampling not only in terms of sample efficiency but also in terms of privacy.The three techniques developed in this thesis improve the scalability of machine learning while ensuring robust privacy protection, and aim to offer solutions for the effective and safe application of machine learning in large datasets.
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| 48. |
- Ghourchian, Hamid, et al.
(author)
-
Block Source Coding with Sequential Encoding
- 2019
-
In: 2019 IEEE Information Theory Workshop, ITW 2019. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538669006
-
Conference paper (peer-reviewed)abstract
- We introduce the concept of achievable cumulative rate distribution functions (CRDF) to characterize sequentially encoding processes that ensure a lossless or lossy reconstruction subject to an average distortion using a non-causal decoder. Utilizing tools from majorization theory, we derive necessary and sufficient conditions on the CRDF for a given IID source. It turns out that the optimal achievable distortion level can be adequately characterized by the concave-hull of the CRDF.
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| 49. |
- Ghourchian, Hamid
(author)
-
On Secure and Sequential Source Coding
- 2023
-
Doctoral thesis (other academic/artistic)abstract
- Secure source coding is an important research area in recent years as it deals with the problem of transmitting sensitive information over insecure channels while protecting it from unauthorized access. This is particularly relevant in the context of modern communication systems where the data transmitted is often sensitive in nature and the threat of eavesdropping or data breaches is high. By developing efficient and secure source coding techniques, it is possible to ensure the confidentiality and integrity of the transmitted information, thereby protecting the privacy and security of the users. In addition, secure source coding also plays a critical role in various applications such as sensor networks, wireless communications, and cloud computing. In this thesis, we explore the topic of secure source coding from an information theoretic perspective and focus on two main problems. In the first problem, we have successfully characterized the entire achievable rate-distortion-equivocation region of a specific instance of a classic problem. We investigate the challenge of balancing the trade-off between the rate of data compression, the level of distortion in the compressed data, and the amount of information leaked to an eavesdropper when a private key is shared between the sender and the receiver. Specifically, we concentrate on a scenario where the decoder and eavesdropper have access to different side-informations that are correlated with the source.In the second problem, the focus is on studying secure rate-distortion coding, where data is compressed and transmitted in a block-wise, causal manner, and the decoding is done non-causally. A new concept called cumulative rate distribution functions (CRDFs) is introduced to describe the rate resources that are spent sequentially to compress the sequence, while the concept of cumulative leakage distribution functions (CLFs) is used to characterize the security constraints on the amount of information leakage. Using techniques from majorization theory, necessary and sufficient conditions are derived for the achievable CRDFs for a given independent and identically distributed (IID) source and CLF, and it was found that the concave-hull of the CRDF characterizes the optimal achievable rate distribution. It is also extended to consider the scenario where there is a wiretap channel between the encoder, decoder, and eavesdropper, and inner and outer bounds as well as a closed-solution for a specific case of wiretap channels are found.
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| 50. |
- Ghourchian, Hamid, et al.
(author)
-
Secure Block Joint Source-Channel Coding with Sequential Encoding
- 2023
-
In: 2023 IEEE International Symposium on Information Theory, ISIT 2023. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 2732-2737
-
Conference paper (peer-reviewed)abstract
- We extend the results of Ghourchian et al. [1] to joint source-channel coding with eavesdropping. Our work characterizes the sequential encoding process using the cumulative rate distribution functions (CRDF) and includes a security constraint using the cumulative leakage distribution functions (CLF). The information leakage is defined based on the mutual information between the source and the output of the wiretap channel to the eavesdropper. We derive inner and outer bounds on the achievable CRDF for a given source and CLF, and show that the bounds are tight when the distribution achieving the capacity of the wiretap channel is the same as the one achieving the capacity of the channel.
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