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1.	Avula, Ramana R., et al. (författare) Privacy-preserving smart meter control strategy including energy storage losses 2018 Ingår i: Proceedings - 2018 IEEE PES Innovative Smart Grid Technologies Conference Europe, ISGT-Europe 2018. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538645055 Konferensbidrag (refereegranskat)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.
2.	Avula, Ramana Reddy, 1993-, et al. (författare) Smart Meter Privacy Control Strategy Including Energy Storage Degradation 2019 Ingår i: 2019 IEEE Milan PowerTech. - : IEEE. Konferensbidrag (refereegranskat)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.
3.	Cao, Le Phuong, et al. (författare) Optimal transmit strategy for MIMO channels with joint sum and per-antenna power constraints 2017 Ingår i: 2017 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP). - : IEEE. - 9781509041176 ; , s. 3569-3573 Konferensbidrag (refereegranskat)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.
4.	Cao, Le Phuong, et al. (författare) Transmit Beamforming for Single-User Large-Scale MISO Systems With Sub-Connected Architecture and Power Constraints 2018 Ingår i: IEEE Communications Letters. - : IEEE. - 1089-7798 .- 1558-2558. ; 22:10, s. 2096-2099 Tidskriftsartikel (refereegranskat)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.
5.	Cao, Phuong, et al. (författare) Optimal Transmission Rate for MISO Channels with Joint Sum and Per-antenna Power Constraints 2015 Ingår i: IEEE International Conference on Communications (ICC), London, June 08-12, 2015. - 9781467364324 ; , s. 4727-4732 Konferensbidrag (refereegranskat)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.
6.	Cao, Phuong, et al. (författare) Optimal Transmit Strategies for Gaussian MISO Wiretap Channels 2018 Ingår i: IEEE Transactions on Information Forensics and Security. - 1556-6013 .- 1556-6021. Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)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.
7.	Cao, Phuong, et al. (författare) Precoding Design for Massive MIMO Systems with Sub-connected Architecture and Per-antenna Power Constraints 2018 Konferensbidrag (refereegranskat)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.
8.	Cervia, Giulia, et al. (författare) Fixed-Length Strong Coordination 2019 Ingår i: 2019 IEEE Information Theory Workshop, ITW 2019. - : Institute of Electrical and Electronics Engineers Inc.. - 9781538669006 Konferensbidrag (refereegranskat)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.
9.	Do, Hieu T., et al. (författare) Interfering Relay Channels 2017 Ingår i: Entropy. - : MDPI AG. - 1099-4300. ; 19:9 Tidskriftsartikel (refereegranskat)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.
10.	Do, Tan Tai, et al. (författare) Capacity analysis of uplink WCDMA systems with imperfect channel state information 2015 Ingår i: IEEE Vehicular Technology Conference. - : IEEE. - 9781479980888 Konferensbidrag (refereegranskat)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.
11.	Do, Tan Tai, et al. (författare) Uplink Waveform Channel With Imperfect Channel State Information and Finite Constellation Input 2017 Ingår i: IEEE Transactions on Wireless Communications. - : IEEE Press. - 1536-1276 .- 1558-2248. ; 16:2, s. 1107-1119 Tidskriftsartikel (refereegranskat)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.
12.	Do, Tan Tai, et al. (författare) Waveform domain framework for capacity analysis of uplink WCDMA systems 2015 Ingår i: EURASIP Journal on Wireless Communications and Networking. - : Springer. - 1687-1472 .- 1687-1499. Tidskriftsartikel (refereegranskat)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.
13.	Ghourchian, Hamid, et al. (författare) Block Source Coding with Sequential Encoding 2019 Ingår i: 2019 IEEE Information Theory Workshop, ITW 2019. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538669006 Konferensbidrag (refereegranskat)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.
14.	Goubet, Olivier, et al. (författare) Low-Complexity Scalable Iterative Algorithms for IEEE 802.11p Receivers 2015 Ingår i: IEEE Transactions on Vehicular Technology. - 0018-9545 .- 1939-9359. ; 64:9, s. 3944-3956 Tidskriftsartikel (refereegranskat)abstract In this paper, we investigate receivers for vehicle-to- vehicle (V2V) and vehicle-to-infrastructure (V2I) communications. Vehicular channels are characterized by multiple paths and time variations, which introduce challenges in the design of receivers. We propose an algorithm for IEEE 802.11p-compliant receivers, based on orthogonal frequency-division multiplexing (OFDM). We employ iterative structures in the receiver as a way to estimate the channel despite variations within a frame. The channel estimator is based on factor graphs (FGs), which allow the design of soft iterative receivers while keeping acceptable computational complexity. Throughout this paper, we focus on designing a receiver that offers a good complexity-performance tradeoff. Moreover, we propose a scalable algorithm to be able to tune the tradeoff, depending on the channel conditions. Our algorithm allows reliable communications while offering a considerable decrease in computational complexity. In particular, numerical results show the tradeoff between complexity and performance measured in computational time and bit error rate (BER), as well as frame error rate (FER) achieved by various interpolation lengths used by the estimator, which both outperform by decades the standard least squares (LS) solution. Furthermore, our adaptive algorithm shows a considerable improvement in terms of computational time and complexity against state-of-the-art and classical receptors while showing acceptable BER and FER performance.
15.	Kim, Su Min, et al. (författare) On the Entropy Computation of Large Complex Gaussian Mixture Distributions 2015 Ingår i: IEEE Transactions on Signal Processing. - 1053-587X .- 1941-0476. ; 63:17, s. 4710-4723 Tidskriftsartikel (refereegranskat)abstract The entropy computation of Gaussian mixture distributions with a large number of components has a prohibitive computational complexity. In this paper, we propose a novel approach exploiting the sphere decoding concept to bound and approximate such entropy terms with reduced complexity and good accuracy. Moreover, we propose an SNR region-based enhancement of the approximation method to reduce the complexity even further. Using Monte-Carlo simulations, the proposed methods are numerically demonstrated for the computation of the mutual information including the entropy term of various channels with finite constellation modulations such as binary and quadratic amplitude modulation (QAM) inputs for communication applications.
16.	Kittichokechai, Kittipong, et al. (författare) Coding With Action-Dependent Side Information and Additional Reconstruction Requirements 2015 Ingår i: IEEE Transactions on Information Theory. - : IEEE. - 0018-9448 .- 1557-9654. ; 61:11, s. 6355-6367 Tidskriftsartikel (refereegranskat)abstract Two classes of source/channel coding problems, namely, coding with action-dependent side information and coding with additional signal reconstruction are considered in a unified fashion. In the source coding setting, a decoder wishes to reconstruct the source subject to a distortion constraint, while an encoder is required to estimate the decoder's reconstruction reliably. Side information is action-dependent in the sense that its quality and/or availability at the encoder or decoder can be influenced by a cost-constrained action sequence. In the channel coding dual, the decoder wishes to decode both the message and the channel input sequence reliably, and the channel state information available at the encoder or decoder is assumed to depend on the action sequence. We consider discrete memoryless systems and characterize single letter expressions for the rate-distortion-cost function and channel capacity for the respective source and channel coding problems.
17.	Kittichokechai, Kittipong, et al. (författare) Secure Source Coding With a Public Helper 2016 Ingår i: IEEE Transactions on Information Theory. - : IEEE Press. - 0018-9448 .- 1557-9654. ; 62:7, s. 3930-3949 Tidskriftsartikel (refereegranskat)abstract We consider secure multi-terminal source coding problems in the presence of a public helper. Two main scenarios are studied: 1) source coding with a helper where the coded side information from the helper is eavesdropped by an external eavesdropper and 2) triangular source coding with a helper where the helper is considered as a public terminal. We are interested in how the helper can support the source transmission subject to a constraint on the amount of information leaked due to its public nature. We characterize the tradeoff among transmission rate, incurred distortion, and information leakage rate at the helper/eavesdropper in the form of the rate-distortion-leakage region for various classes of problems.
18.	Kittichokechai, Kittipong, et al. (författare) Secure Source Coding With Action-Dependent Side Information 2015 Ingår i: IEEE Transactions on Information Theory. - : IEEE Press. - 0018-9448 .- 1557-9654. ; 61:12, s. 6444-6464 Tidskriftsartikel (refereegranskat)abstract We consider the problems of secure lossy source coding with side information in the presence of a passive eavesdropper who has access to the source description. The encoder wishes to compress the source sequence in order to satisfy a distortion criterion at the decoder, while revealing only limited knowledge about the source to the eavesdropper. The side information available to the encoder, the legitimate decoder, or the eavesdropper can be influenced by a cost-constrained action sequence. Three different settings are studied. In the first two settings, we are interested in understanding the influence of the action sequence on the rate-distortion-leakage tradeoff where the action is taken either by the decoder or by the encoder to influence side information at the decoder and eavesdropper. Next, we consider a setting where common action-dependent side information is available securely to both encoder and decoder, and thus can be used for secret key generation. We characterize the optimal rate-distortion-cost-leakage region or the corresponding inner bounds for a discrete memoryless source for above settings. The results are useful in characterizing fundamental limits for example in secure sensor networking and future cyber physical systems.
19.	Li, Zuxing, et al. (författare) Privacy Against a Hypothesis Testing Adversary 2019 Ingår i: IEEE Transactions on Information Forensics and Security. - : Institute of Electrical and Electronics Engineers (IEEE). - 1556-6013 .- 1556-6021. ; 14:6, s. 1567-1581 Tidskriftsartikel (refereegranskat)abstract Privacy against an adversary (AD) that tries to detect the underlying privacy-sensitive data distribution is studied. The original data sequence is assumed to come from one of the two known distributions, and the privacy leakage is measured by the probability of error of the binary hypothesis test carried out by the AD. A management unit (MU) is allowed to manipulate the original data sequence in an online fashion while satisfying an average distortion constraint. The goal of the MU is to maximize the minimal type II probability of error subject to a constraint on the type I probability of error assuming an adversarial Neyman-Pearson test, or to maximize the minimal error probability assuming an adversarial Bayesian test. The asymptotic exponents of the maximum minimal type II probability of error and the maximum minimal error probability are shown to be characterized by a Kullback-Leibler divergence rate and a Chernoff information rate, respectively. Privacy performances of particular management policies, the memoryless hypothesis-aware policy and the hypothesis-unaware policy with memory, are compared. The proposed formulation can also model adversarial example generation with minimal data manipulation to fool classifiers. At last, the results are applied to a smart meter privacy problem, where the user's energy consumption is manipulated by adaptively using a renewable energy source in order to hide user's activity from the energy provider.
20.	Li, Zuxing, et al. (författare) Privacy against adversarial hypothesis testing : Theory and application to smart meter privacy problem 2019 Ingår i: Privacy in Dynamical Systems. - Singapore : Springer Singapore. - 9789811504938 - 9789811504921 ; , s. 43-64 Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract Hypothesis testing is the fundamental theory behind decision-making and therefore plays a critical role in information systems. A prominent example is machine learning, which is currently developed and applied to a wide range of applications. However, besides the utilities, hypothesis testing can also be implemented for an illegitimate purpose to infer on people’s privacy. Thus, the development of hypothesis testing techniques further increases the privacy leakage risks. Accordingly, the research on privacy-by-design techniques that enhance the privacy against adversarial hypothesis testing receives more and more attention recently. In this chapter, the problem of privacy against adversarial hypothesis testing is formulated in the presence of a distortion source. Information-theoretic fundamental bounds on the optimal privacy performance and corresponding privacy-enhancing technologies are first discussed under the assumption of independent and identically distributed adversarial observations. The discussion is then extended to considering a privacy problem model with memory. In the end, applications of the theoretic results and privacy-enhancing technologies to the smart meter privacy problem are illustrated.
21.	Li, Z., et al. (författare) Privacy-utility management of hypothesis tests 2019 Ingår i: 2018 IEEE Information Theory Workshop, ITW 2018. - : Institute of Electrical and Electronics Engineers Inc.. - 9781538635995 Konferensbidrag (refereegranskat)abstract The trade-off of hypothesis tests on the correlated privacy hypothesis and utility hypothesis is studied. The error exponent of the Bayesian composite hypothesis test on the privacy or utility hypothesis can be characterized by the corresponding minimal Chernoff information rate. An optimal management protects the privacy by minimizing the error exponent of the privacy hypothesis test and meanwhile guarantees the utility hypothesis testing performance by satisfying a lower bound on the corresponding minimal Chernoff information rate. The asymptotic minimum error exponent of the privacy hypothesis test is shown to be characterized by the infimum of corresponding minimal Chernoff information rates subject to the utility guarantees.
22.	Mochaourab, Rami, et al. (författare) Private Filtering for Hidden Markov Models 2018 Ingår i: IEEE Signal Processing Letters. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1070-9908 .- 1558-2361. ; 25:6 Tidskriftsartikel (refereegranskat)abstract Consider a hidden Markov model describing a system with two types of states: a monitored state and a private state. The two types of states are dependent and evolve jointly according to a Markov process with a stationary transition probability. It is desired to reveal the monitored states to a receiver but hide the private states. For this purpose, a privacy filter is necessary which suitably perturbs the monitored states before communication to the receiver. Our objective is to design the privacy filter to optimize the trade-off between monitoring accuracy and privacy, measured through a time-invariant distortion measure and Shannon's equivocation, respectively. As the optimal privacy filter is difficult to compute using dynamic programming, we adopt a suboptimal greedy approach through which the privacy filter can be computed efficiently. Here, the greedy approach has the additional advantage of not being restricted to finite time horizon setups. Simulations show the superiority of the approach compared to a privacy filter which only adds independent noise to the observations.
23.	Moles-Cases, Vicent, et al. (författare) A Comparison of OFDM, QAM-FBMC, and OQAM-FBMC Waveforms Subject to Phase Noise 2017 Ingår i: 2017 IEEE International Conference on Communications (ICC). - : IEEE. - 9781467389990 Konferensbidrag (refereegranskat)abstract Frequencies above 6 GHz are being considered by mobile communication industry for the deployment of future 5G networks. However in the higher carrier frequencies, especially the millimeter-wave frequencies (above 30 GHz), there can be severe degradations in the transmitted and received signals due to Phase Noise (PN) introduced by the local oscillators. In this paper, the effect of PN has been investigated for Orthogonal Frequency Division Multiplexing (OFDM), Offset QAM Filter-Bank Multi-Carrier (OQAM-FBMC) and QAM Filter-Bank Multi-Carrier (QAM-FBMC). The sources of degradation in these waveforms are quantified and closed-form expressions are derived for Signal-to-Interference Ratio (SIR). Evaluations are performed in terms of SIR and Symbol Error Rate (SER) for mm-wave frequencies using mmMAGIC PN model. The results reveal that OFDM outperforms OQAM-FBMC and QAM-FBMC and is a promising candidate for mm-wave communication.
24.	Oechtering, Tobias J., 1975-, et al. (författare) Coordination Coding with Causal Decoder for Vector-valued Witsenhausen Counterexample Setups 2019 Ingår i: 2019 IEEE Information Theory Workshop, ITW 2019. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538669006 ; , s. 309-313 Konferensbidrag (refereegranskat)abstract The vector-valued extension of the famous Witsenhausen counter-example setup is studied where the first decision maker (DM1) non-causally knows and encodes the iid state sequence and the second decision maker (DM2) causally estimates the interim state. The coding scheme is transferred from the finite alphabet coordination problem for which it is proved to be optimal. The extension to the Gaussian setup is based on a non-standard weak typicality approach and requires a careful average estimation error analysis since the interim state is estimated by the decoder. Next, we provide a choice of auxiliary random variables that outperforms any linear scheme. The optimal scheme remains unknown.
25.	Tanaka, Takashi, et al. (författare) Rate of prefix-free codes in LQG control systems 2016 Ingår i: 2016 IEEE International Symposium on Information Theory - Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509018062 ; , s. 2399-2403 Konferensbidrag (refereegranskat)abstract In this paper, we consider a discrete time linear quadratic Gaussian (LQG) control problem in which state information of the plant is encoded in a variable-length binary codeword at every time step, and a control input is determined based on the codewords generated in the past. We derive a lower bound of the rate achievable by the class of prefix-free codes attaining the required LQG control performance. This lower bound coincides with the infimum of a certain directed information expression, and is computable by semidefinite programming (SDP). Based on a technique by Silva et al., we also provide an upper bound of the best achievable rate by constructing a controller equipped with a uniform quantizer with subtractive dither and Shannon-Fano coding. The gap between the obtained lower and upper bounds is less than 0:754r + 1 bits per time step regardless of the required LQG control performance, where r is the rank of a signal-to-noise ratio matrix obtained by SDP, which is no greater than the dimension of the state.
26.	Treust, M. L., et al. (författare) Optimal Control Designs for Vector-valued Witsenhausen Counterexample Setups 2019 Ingår i: 2018 56th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2018. - : Institute of Electrical and Electronics Engineers Inc.. ; , s. 532-537 Konferensbidrag (refereegranskat)abstract In this work, necessary and sufficient conditions for empirical coordination of vector-valued Witsenhausen counter-example two terminal setups with non-classical information structure are derived. Vector-valued processing allows to involve coding in the design of the control strategies. Optimal characterizations are obtained for the non-causal encoding and causal decoding case as well as causal encoding and non-causal decoding case. Necessary and sufficient conditions are provided for the case with both non-causal encoding and decoding. The feasible set of target distributions can serve as optimization domain for characterizing the optimal average cost, in particular using Witsenhausen's cost function.
27.	Vu, Minh Thành, et al. (författare) Gaussian hierarchical identification with pre-processing 2018 Ingår i: Data Compression Conference Proceedings. - : Institute of Electrical and Electronics Engineers Inc.. - 9781538648834 ; , s. 277-286 Konferensbidrag (refereegranskat)abstract In this work we consider a two-stage identification problem with pre-processing where the users' data and observation are Gaussian distributed. In the first stage the processing unit returns a list of compatible users using the information from the first storage layer and the pre-processed observation. Then, the refined search is performed in the second stage where the processing unit returns the exact user's identity and a corresponding reconstruction sequence. We provide a complete rate-distortion trade-off for the Gaussian setting.
28.	Vu, Minh Thành, et al. (författare) Hierarchical identification with pre-processing 2017 Ingår i: 2017 IEEE International Symposium on Information Theory (ISIT). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509040964 ; , s. 2746-2750 Konferensbidrag (refereegranskat)abstract We study a two-stage identification problem with pre-processing to enable efficient data retrieval and reconstruction. The first stage outputs a list of compatible users to the second stage which uses it to return the exact user identity with a corresponding reconstruction sequence. The rate distortion region is characterized. A connection to a two observer identification problem is also studied.
29.	Vu, Minh Thành, et al. (författare) Hierarchical Identification with Pre-processing 2019 Ingår i: IEEE Transactions on Information Theory. - : IEEE. - 0018-9448 .- 1557-9654. ; 66:1, s. 82-113 Tidskriftsartikel (refereegranskat)abstract We study a two-stage identification problem with pre-processing to enable efficient data retrieval and reconstruc- tion. In the enrollment phase, users’ data are stored into the database in two layers. In the identification phase an observer obtains an observation, which originates from an unknown user in the enrolled database through a memoryless channel. The observation is sent for processing in two stages. In the first stage, the observation is pre-processed, and the result is then used in combination with the stored first layer information in the database to output a list of compatible users to the second stage. Then the second step uses the information of users contained in the list from both layers and the original observation sequence to return the exact user identity and a corresponding reconstruction sequence. The rate-distortion regions are characterized for both discrete and Gaussian scenarios. Specifically, for a fixed list size and distortion level, the compression-identification trade-off in the Gaussian scenario results in three different operating cases characterized by three auxiliary functions. While the choice of the auxiliary random variable for the first layer information is essentially unchanged when the identification rate is varied, the second one is selected based on the dominant function within those three. Due to the presence of a mixture of discrete and continuous random variables, the proof for the Gaussian case is highly non-trivial, which makes a careful measure theoretic analysis necessary. In addition, we study a connection of the previous setting to a two observer identification and a related problem with a lower bound for the list size, where the latter is motivated from privacy concerns.
30.	Vu, Minh thanh, et al. (författare) Lossy distributed storage with limited failure loss 2015 Ingår i: Proceedings of the International Symposium on Wireless Communication Systems. - : VDE Verlag GmbH. - 9781467365406 ; , s. 191-195 Konferensbidrag (refereegranskat)abstract In this paper a successive refinement problem is considered where decoders can access only distributed storage nodes, subject to an additional constraint on the loss of information if failures happen. We characterize the optimal tradeoff for a given a distortion tuple and an equivocation constraint between storage nodes. A binary example is provided to illustrate the trade-off between the loss of information constraint and the corresponding achievable rate region.
31.	Vu, Minh Thành, et al. (författare) Operational Equivalence of Distributed Hypothesis Testing and Identification Systems 2019 Ingår i: Proceedings 2019 IEEE International Symposium on Information Theory (ISIT). - : IEEE. ; , s. 1999-2003 Konferensbidrag (refereegranskat)abstract In this paper we revisit the connections of the distributed hypothesis testing against independence (HT) problem with the Wyner-Ahlswede-Korner (WAK) problem and the identification systems (ID). We show that the strong converse for the WAK problem is equivalent to the strong converse for the HT problem via constructive and nonconstructive transformations of codes. As another consequence of the transformation we provide a new exponentially strong converse equivalence statement. Applying the same idea, we prove a new result that the epsilon-identification capacity of the ID problem is equal to the maximum epsilon-exponent of type II of error in the HT problem when both side compression is allowed.
32.	Vu, Minh Thành (författare) Perspectives on Identification Systems 2019 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract Identification systems such as biometric identification systems have been becoming ubiquitous. Fundamental bounds on the performance of the systems have been established in literature. In this thesis we further relax several assumptions in the identification problem and derive the corresponding fundamental regions for these settings.The generic identification architecture is first extended so that users’ information is stored in two layers. Additionally, the processing is separated in two steps where the observation sequence in the first step is a noisy, pre-processed version of the original one. This setting generalizes several known settings in the literature. Given fixed pre-processing schemes, we study optimal trade-offs in the discrete and Gaussian cases. As corollaries we also provide characterizations for related problems.In a second aspect, the joint distribution in the identification problem is relaxed in several ways. We first assume that all users’ sequences are drawn from a common distribution, which depends on a state of the system. The observation sequence is induced by a channel which has its own state. Another variant, in which the channel is fixed, however the distributions of users’ sequences are not necessarily identical, is considered next. We then study the case that users’ data sequence are generated independently from a mixture distribution. Optimal performance regions of these settings are provided. We further give an inner bound and an outer bound on the region when the observation channel varies arbitrarily. Additionally, we strengthen the relation between the Wyner-Ahlswede-Körner problem and the identification problem and show the equivalence of these two.Finally, we study a binary hypothesis testing problem which decides whether or not the observation sequence is related to one user in the database. The optimal exponent of the second type of error is studied. Furthermore, we show that the single-user testing against independence problem studied by Ahlswede and Csiszár is equivalent to the identification problem as well as the Wyner-Ahlswede-Körner problem.
33.	Vu, Minh Thành, et al. (författare) Polar code for secure Wyner-Ziv coding 2017 Ingår i: 8th IEEE International Workshop on Information Forensics and Security, WIFS 2016. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509011384 Konferensbidrag (refereegranskat)abstract Secure source coding provides the methods to compress data efficiently taking the risks of unauthorized access into account. However standard information-Theoretic achievability proofs only show the existence of a coding scheme without providing a concrete code design. In the paper we provide an alternative proof of achievability for the secure Wyner-Ziv source coding problem with side information at the eavesdropper using polar coding. Due to the recent algorithmic advances in the design of polar codes, our result is highly relevant for future big data applications since it provides the basis for further developments.
34.	Vu, Minh Thành, et al. (författare) Successive refinement with cribbing and side information 2017 Ingår i: 54th Annual Allerton Conference on Communication, Control, and Computing, Allerton 2016. - : IEEE. - 9781509045495 ; , s. 70-77 Konferensbidrag (refereegranskat)abstract In this work we consider the successive refinement with side information where decoders cooperate via a cribbing link. Rate-distortion regions are characterized for non-causal side information and causal side information under appropriate constraints. An example is provided to illustrate the rate-distortion region for non-causal side information.
35.	Vu, Minh Thành, et al. (författare) Testing in Identification Systems 2018 Ingår i: 2018 IEEE INFORMATION THEORY WORKSHOP (ITW). - : IEEE. - 9781538635995 ; , s. 295-299 Konferensbidrag (refereegranskat)abstract We study a hypothesis testing problem to decide whether or not an observation sequence is related to one of users in a database which contains compressed versions of users' data. Our main interest lies on the characterization of the exponent of the probability of the second kind of error when the number of users in the database grows exponentially. We show a lower bound on the error exponent and identify special cases where the bound is tight. Next, we study the c-achievable error exponent and show a sub-region where the lower bound is tight.
36.	Vu, Minh Thành, et al. (författare) Uncertainty in Identification Systems 2018 Ingår i: IEEE International Symposium on Information Theory - Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 2386-2390 Konferensbidrag (refereegranskat)abstract We study the high-dimensional identification systems under the presence of statistical uncertainties. The task is to design mappings for enrollment and identification purposes. The identification mapping compresses users' information then stores the index in the corresponding position in a database. The identification mapping combines the information in the database and the observation which originates randomly from an enrolled user to produce an estimate of the underlying user index. We study two scenarios. Users' data are generated from the same unknown distribution while the observation channel is also subjected to uncertainty. Each user's data are generated iid from the distribution corresponding to its own state, while the observation channel is known. We provide an achievable compression-identification trade-off for the first and second settings considering both discrete and continuous cases. In the discrete scenario, the described regions are also the correspondingly complete characterizations.
37.	Wiese, Moritz, et al. (författare) Secure distributed estimation of linear systems 2017 Ingår i: 2016 IEEE Conference on Communications and Network Security, CNS 2016. - : Institute of Electrical and Electronics Engineers Inc.. - 9781509030651 ; , s. 616-620 Konferensbidrag (refereegranskat)abstract A two-dimensional linear time-invariant system is considered. The two dimensions of its states are observed by one sensor each. Every sensor quantizes its observations into a finite number of messages, using also the other sensor's past decisions. The combined sensor outputs should allow for a bounded estimation error (reliability). For a natural quantizer, we identify the cases where a price in the quantizer sum rate has to be paid for the fact that observations are distributed. At the same time, an eavesdropper should not be able to track the system state (security). Using the same quantizer as before, security is shown to be possible if the eavesdropper has less information than the estimator in that it for each sensor message pair obtains a larger set of indistinguishable message pairs.
38.	Wiese, Moritz, et al. (författare) Secure Estimation and Zero-Error Secrecy Capacity 2019 Ingår i: IEEE Transactions on Automatic Control. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9286 .- 1558-2523. ; 64:3, s. 1047-1062 Tidskriftsartikel (refereegranskat)abstract We study the problem of securely estimating the states of an unstable dynamical system subject to non-stochastic disturbances. The estimator obtains all its information through an uncertain channel, which is subject to nonstochastic disturbances as well, and an eavesdropper obtains a disturbed version of the channel inputs through a second uncertain channel. An encoder observes and block encodes the states in such a way that, upon sending the generated codeword, the estimator's error is bounded and a security criterion is satisfied, thereby ensuring that the eavesdropper obtains as little state information as possible. Two security criteria are considered and discussed with the help of a numerical example. A sufficient condition on the uncertain wiretap channel, i.e., the pair formed by the uncertain channel from the encoder to the estimator and the uncertain channel from the encoder to the eavesdropper is derived, which ensures that a bounded estimation error and security are achieved. This condition is also shown to be necessary for a subclass of uncertain wiretap channels. To formulate the condition, the zero-error secrecy capacity of uncertain wiretap channels is introduced, i.e., the maximal rate at which data can be transmitted from the encoder to the estimator in such a way that the eavesdropper is unable to reconstruct the transmitted data. Finally, the zero-error secrecy capacity of uncertain wiretap channels is studied.
39.	Wiese, Moritz, et al. (författare) Secure Estimation for Unstable Systems 2016 Ingår i: 2016 IEEE 55th Conference on Decision and Control, CDC 2016. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509018376 ; , s. 5059-5064 Konferensbidrag (refereegranskat)abstract We assume that the states of an unstable dynamical system are encoded and sent to an estimator through an uncertain channel, which is a channel disturbing its inputs in a nonstochastic manner. The encoder's codeword is also fed into another uncertain channel, at whose output an eavesdropper is listening. The estimator should obtain a uniformly bounded system state estimation error, whereas the eavesdropper's information about the system states should be subject to a security constraint. We find a condition on the relation between the uncertain channel from encoder to estimator and the uncertain channel from encoder to eavesdropper which if satisfied allows for at least one of the two following security criteria to hold: The volume of the set of states possible acccording to the eavesdropper's information tends to infinity at exponential speed-by itself (strong security) or if divided by the volume of the set of states possible according to the estimator's information (weak security).
40.	Wiese, Moritz, et al. (författare) Uncertain wiretap channels and secure estimation 2016 Ingår i: 2016 IEEE International Symposium on Information Theory. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509018062 ; , s. 2004-2008 Konferensbidrag (refereegranskat)abstract The zero-error secrecy capacity of uncertain wiretap channels is defined. If the sensor-estimator channel is perfect, it is also calculated. Further properties are discussed. The problem of estimating a dynamical system with nonstochastic disturbances is studied where the sensor is connected to the estimator and an eavesdropper via an uncertain wiretap channel. The estimator should obtain a uniformly bounded estimation error whereas the eavesdropper's error should tend to infinity. It is proved that the system can be estimated securely if the zero-error capacity of the sensor-estimator channel is strictly larger than the logarithm of the system's unstable pole and the zero-error secrecy capacity of the uncertain wiretap channel is positive.
41.	You, Yang, et al. (författare) Optimal Privacy-Enhancing and Cost-Efficient Energy Management Strategies for Smart Grid Consumers 2018 Ingår i: 2018 IEEE Statistical Signal Processing Workshop, SSP 2018. - : Institute of Electrical and Electronics Engineers Inc.. ; , s. 144-148 Konferensbidrag (refereegranskat)abstract The design of optimal energy management strategies that trade-off consumers' privacy and expected energy cost by using an energy storage is studied. The Kullback-Leibler divergence rate is used to assess the privacy risk of the unauthorized testing on consumers' behavior. We further show how this design problem can be formulated as a belief state Markov decision process problem so that standard tools of the Markov decision process framework can be utilized, and the optimal solution can be obtained by using Bellman dynamic programming. Finally, we illustrate the privacy-enhancement and cost-saving by numerical examples.
42.	Zhou, Linghui, et al. (författare) Fundamental Limits for Biometric Identification Systems without Privacy Leakage 2019 Ingår i: Proceedings 57th Annual Allerton Conference on Communication, Control, and Computing (Allerton). - : IEEE. - 9781728131511 - 9781728131528 Konferensbidrag (refereegranskat)abstract Wewithout privacy leakage. Privacy-preserving biometric identifi- cation systems that involve helper data, secret keys and private keys are considered. The helper data are stored in a public database and can be used to support the user identification. The secret key is either stored in an encrypted database or handed to the user, which can be used for authentication. Since the helper data are public and releasing the biometric information invokes privacy issues, the public helper data can only leak a negligible amount of biometric information. To achieve this, we use private keys to mask the helper data such that the public helper data contain as little as possible information about the biometrics. Moreover, a two-stage extension is also studied, where the clustering method is used such that the search complexity in the identification phase can be reduced. identification
43.	Zhou, Linghui, et al. (författare) Polar Codes for Identification Systems 2019 Ingår i: Proceedings of the 12th International ITG Conference on Systems, Communications and Coding. - 9783800748624 Konferensbidrag (refereegranskat)abstract In this paper, we study compression and identifica- tion algorithms for the identification systems using polar codes. High dimensional feature vectors representing users are first compressed and then enrolled in a database. When an unknown enrolled user is observed, the noisy observation is compared with the entries in the database and the processing unit outputs an estimated user index. We develop three approaches based on polar codes and apply them to identification systems. This is the first time that identification system based on polar codes is studied. In particular, the identification mapping is challenging. The proposed methods provide a framework of applying polar codes to identification systems. The numerical evaluation results show that they results in complexity linearly depends on the number of users and low identification error rates as the sequence length increases.

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