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See detailJoint Compression and Feedback of CSI in Correlated multiuser MISO Channels
Alodeh, Maha UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in The 17th IEEE International workshop on Signal Processing advances in Wireless Communications (2016, July)

The potential gains of multiple antennas in wireless systems can be limited by the channel state information imperfections. In this context, this paper tackles the feedback in multiuser correlated ... [more ▼]

The potential gains of multiple antennas in wireless systems can be limited by the channel state information imperfections. In this context, this paper tackles the feedback in multiuser correlated multiple input single output (MU-MISO). We propose a framework to feedback the minimum number of bits without performance degradation. This framework is based on decorrelating the channel state information by compression and then quantize the compressed (CSI) and feedback it to the base station (BS). We characterize the rate loss resulted from the proposed framework. An upper bound on the rate loss is derived in terms of the amount of feedback and the statistics of the channel. Based on this characterization, we propose am adaptive bit allocation algorithm that takes into the account the channel statistics to reduce the rate loss induced by the quantization. Moreover, in order to maintain a constant rate loss with respect to the perfect CSIT case, it is shown that the number of feedback bits should scale linearly with the SNR (in dB) and to the rank of the user transmit correlation matrix. We validate the proposed framework by Monte-carlo simulations. [less ▲]

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See detailA Joint Day-to-Day Mode and Within-Day Departure Time Choice Model for the Analysis of Dynamic Ridesharing
Viti, Francesco UL; Corman, Francesco

Scientific Conference (2014, June 19)

Sharing travels is an effective way to increase car occupancy rates and to reduce the total number of cars for the same distances travelled. A potentially attractive service based on the sharing concept ... [more ▼]

Sharing travels is an effective way to increase car occupancy rates and to reduce the total number of cars for the same distances travelled. A potentially attractive service based on the sharing concept is dynamic ridesharing (DRS), where a service provider matches up driver and passenger with similar itineraries and time schedules with an automated program. To analyse how modal shift from single passenger use of the car to high occupancy one can be realized and what are the demand management solutions that can effectively be recommended, we deal with a theoretically interesting basic model structure of a single-link case, in which we study the complex interaction of multiple factors involved in the dynamic ridesharing problem, and the joint sensitivity to the most relevant parameters involved in this behavioural process. The main contribution of this study is therefore a unified framework that is able to model the dynamics of the departure time, characterized as a within-day process, while keeping the mode choice as a day-to-day process, and characterizing explicitly the matching process of DRS. [less ▲]

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See detailJoint Decoding and Adaptive Compression with QoS Constraint for Uplinks in Cloud Radio Access Networks
Vu, Thang Xuan UL; Quek, Tony Q. S.; Nguyen, Hieu Duy

in 2015 IEEE Global Communications Conference (GLOBECOM) (2015)

Detailed reference viewed: 84 (2 UL)
See detailThe joint distribution of income and wealth
Jäntti, Markus; Sierminska, Eva M.; Van Kerm, Philippe UL

in Gornick, Janet; Jäntti, Markus (Eds.) Economic Inequality in Cross-National Perspective (2013)

Detailed reference viewed: 83 (2 UL)
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See detailJoint Estimation of Mutual Coupling, Element Factor, and Phase Center in Antenna Arrays
Mowlér, Marc; Larsson, Erik G.; Lindmark, Björn et al

in EURASIP Journal on Wireless Communications & Networking (2007), 2007

Detailed reference viewed: 7 (0 UL)
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See detailA joint exploration of executive subcomponents in binge drinking
Lannoy, Séverine; Dormal, Valérie; Billieux, Joël UL et al

in Addiction Research and Theory (2019), 27(6), 498-506

Background: Executive deficits have been largely reported in young binge drinkers during the last decade, but uncertainty remains regarding the specificity of these deficits and their variation across ... [more ▼]

Background: Executive deficits have been largely reported in young binge drinkers during the last decade, but uncertainty remains regarding the specificity of these deficits and their variation across executive subcomponents. The current study aimed at offering a theoretically-grounded and specific exploration of the differential deficits observed across executive functions in binge drinkers. Method: A total of forty university students (20 binge drinkers; 10 women, and 20 matched controls; 12 women) performed three validated neuropsychological tasks, each exploring a specific executive function, namely shifting, updating, and inhibition (specifically Resistance to Distractor Interference). Tasks were presented to participants in pseudo-randomized order. Repeated measure analyses of variance were performed for each task to compare groups’ performance. Results: A dissociation was observed across executive tasks regarding group differences: compared to controls, binge drinkers demonstrated preserved performance for shifting and updating abilities, but impaired inhibition. These results support the central role of inhibitory control in excessive alcohol consumption. In contrast with severe alcohol-use disorders, binge drinking does not appear related to a general executive deficit. Conclusions: In view of the pivotal role played by inhibition impairments in the emergence of severe alcohol-use disorders, the present data claim for developing individualized evaluation and rehabilitation programs focusing on this executive subcomponent to improve control abilities at early stages of alcohol-related disorders. [less ▲]

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See detailJoint mouse-human phenome-wide association to test gene function and disease risk.
Wang, Xusheng; Pandey, Ashutosh K.; Mulligan, Megan K. et al

in Nature communications (2016), 7

Phenome-wide association is a novel reverse genetic strategy to analyze genome-to-phenome relations in human clinical cohorts. Here we test this approach using a large murine population segregating for ... [more ▼]

Phenome-wide association is a novel reverse genetic strategy to analyze genome-to-phenome relations in human clinical cohorts. Here we test this approach using a large murine population segregating for approximately 5 million sequence variants, and we compare our results to those extracted from a matched analysis of gene variants in a large human cohort. For the mouse cohort, we amassed a deep and broad open-access phenome consisting of approximately 4,500 metabolic, physiological, pharmacological and behavioural traits, and more than 90 independent expression quantitative trait locus (QTL), transcriptome, proteome, metagenome and metabolome data sets--by far the largest coherent phenome for any experimental cohort (www.genenetwork.org). We tested downstream effects of subsets of variants and discovered several novel associations, including a missense mutation in fumarate hydratase that controls variation in the mitochondrial unfolded protein response in both mouse and Caenorhabditis elegans, and missense mutations in Col6a5 that underlies variation in bone mineral density in both mouse and human. [less ▲]

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See detailJoint Power Allocation and Access Point Selection for Cell-free Massive MIMO
Vu, Thang Xuan UL; Chatzinotas, Symeon UL; ShahbazPanahi, Shahram et al

in IEEE International Conference on Communications (2020)

Cell-free massive multiple-input multiple-output (CF-MIMO) is a promising technological enabler for fifth generation (5G) networks in which a large number of access points (APs) jointly serve the users ... [more ▼]

Cell-free massive multiple-input multiple-output (CF-MIMO) is a promising technological enabler for fifth generation (5G) networks in which a large number of access points (APs) jointly serve the users. Each AP applies conjugate beamforming to precode data, which is based only on the AP's local channel state information. However, by having the nature of a (very) large number of APs, the operation of CF-MIMO can be energy-inefficient. In this paper, we investigate the energy efficiency performance of CF-MIMO by considering a practical energy consumption model which includes both the signal transmit energy as well as the static energy consumed by hardware components. In particular, a joint power allocation and AP selection design is proposed to minimize the total energy consumption subject to given quality of service (QoS) constraints. In order to deal with the combinatorial complexity of the formulated problem, we employ norm $l_{2,1}$-based block-sparsity and successive convex optimization to leverage the AP selection process. Numerical results show significant energy savings obtained by the proposed design, compared to all-active APs scheme and the large-scale based AP selection. [less ▲]

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See detailJoint Power Allocation and Distributed Beamforming Design for Multi-Carrier Asynchronous Two-Way Relay Networks
KianiHarchehgani, Sharareh; Shahbazpanahi, Shahram UL; Dong, Min et al

in IEEE International Workshop on Signal Processing Advances in Wireless Communications (SPAWC) 2019, Cannes, July 2019 (2019, July)

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See detailJoint Power Control in Wiretap Interference Channels
Kalantari, Ashkan UL; Maleki, Sina UL; Zheng, Gan et al

in IEEE Transactions on Wireless Communications (2015)

Interference in wireless networks degrades the signal quality at the terminals. However, it can potentially enhance the secrecy rate. This paper investigates the secrecy rate in a two-user interference ... [more ▼]

Interference in wireless networks degrades the signal quality at the terminals. However, it can potentially enhance the secrecy rate. This paper investigates the secrecy rate in a two-user interference network where one of the users, namely user 1, requires to establish a confidential connection. User 1 wants to prevent an unintended user of the network to decode its transmission. User 1 has to transmit such that its secrecy rate is maximized while the quality of service at the destination of the other user, user 2, is satisfied, and both user's power limits are taken into account. We consider two scenarios: 1) user 2 changes its power in favor of user 1, an altruistic scenario, 2) user 2 is selfish and only aims to maintain the minimum quality of service at its destination, an egoistic scenario. It is shown that there is a threshold for user 2's transmission power that only below or above which, depending on the channel qualities, user 1 can achieve a positive secrecy rate. Closed-form solutions are obtained in order to perform joint optimal power control. Further, a new metric called secrecy energy efficiency is introduced. We show that in general, the secrecy energy efficiency of user 1 in an interference channel scenario is higher than that of an interference-free channel. [less ▲]

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See detailJoint Precoding and On-Board Beamforming for Multiple gateway Multibeam Satellite Systems
Joroughi, Vahid UL

in Submitted to IEEE Journal on Selected topic in Communication (JSAC) (in press)

This paper aims to design joint precoding and onboard beamforming of a multiple gateway multibeam satellite system, either in a hybrid space-ground mode, or in a totally on-board one. In such an ... [more ▼]

This paper aims to design joint precoding and onboard beamforming of a multiple gateway multibeam satellite system, either in a hybrid space-ground mode, or in a totally on-board one. In such an architecture, with employing high throughput full frequency reuse pattern over both user and feeder links, each gateway serves a cluster of adjacent beams such that the adjacent clusters are served through a set of gateways that are located at different geographical areas. However, such a system brings in two challenges to overcome. First, the interference in both user and feeder links is the bottleneck of the whole system and applying interference mitigation techniques becomes necessary. Second, as the data demand increases, the ground and space segments should employ extensive bandwidth resources in the feeder link accordingly. This entails embedding an extra number of gateways aiming to support a fair balance between the increasing demand and the corresponding required feeder link resources. To solve these problems, this study investigates the impact of employing a joint multiple gateway architecture and on-board beamforming scheme. It is shown that by properly designing the on-board beamforming scheme, the number of gateways can be kept affordable even if the data demand increases. Moreover, Zero Forcing (ZF) precoding techniques are considered to cope with the interference in both user and feeder links which embed in the following premises: (i) each gateway constructs a part of block ZF precoding matrix, (ii) the satellite and gateways perform the precoding scheme, and (iii) a joint design of ZF precoding and on-board beamforming at the payload of the satellite so that no signal processing scheme is conceived at the gateways. The provided simulation results depict the performance gain obtained by our proposed schemes. [less ▲]

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See detailJoint Precoding with Flexible Power Constraints in Multibeam Satellite Systems
Chatzinotas, Symeon UL; Zheng, Gan UL; Ottersten, Björn UL

in Joint Precoding with Flexible Power Constraints in Multibeam Satellite Systems (2011)

Detailed reference viewed: 133 (7 UL)
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See detailJoint Predistortion and PAPR Reduction in Multibeam Satellite Systems
Mengali, Alberto UL; Shankar, Bhavani UL; Ottersten, Björn UL

in Proceedings of IEEE ICC 2016 (2016, May)

Precoding for multibeam satellites with aggressive frequency reuse has attracted interest of late towards enhancing system capacity. Most of the works on precoding mitigate the linear co-channel ... [more ▼]

Precoding for multibeam satellites with aggressive frequency reuse has attracted interest of late towards enhancing system capacity. Most of the works on precoding mitigate the linear co-channel interference between the beams caused by frequency reuse. How- ever, the high power amplifier (HPA), an integral part of the satellite payload, is inherently non linear. Non-linear amplification combined with the linear co-channel interference introduces non- linear co-channel distortions at the receiver. Further, signals with very high peak to average power ratios (PAPR), typical of spectrally efficient modulations, are sensitive to the non-linear characteristic of the HPA and necessitate large back-off to have manageable distortion levels. In this work, a novel architecture comprising multistream Crest Factor Reduction (signal pre-clipping) and Signal Predistortion (SPD) in cascade, is devised to counter the non- linearities and co-channel interference in multibeam satellite sys- tems. An iterative algorithm to optimize the parameters of the signal clipping and predistortion is devised taking recourse to analytical derivations. The proposed joint estimation paradigm is shown to compare favorably with state-of-art and provides a framework to combine predistortion and precoding. [less ▲]

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See detailThe joint role of impulsivity and distorted cognitions in recreational and problem gambling: A cluster analytic approach.
Devos, Mr Gaetan; Clark, Luke; Bowden-Jones, Henrietta et al

in Journal of affective disorders (2020), 260

BACKGROUND AND AIMS: The Pathways Model (Blaszczynski & Nower, 2002) posits that problem gambling is a heterogeneous disorder with distinct subgroups (behaviorally conditioned gamblers, emotionally ... [more ▼]

BACKGROUND AND AIMS: The Pathways Model (Blaszczynski & Nower, 2002) posits that problem gambling is a heterogeneous disorder with distinct subgroups (behaviorally conditioned gamblers, emotionally vulnerable gamblers, and antisocial-impulsivist gamblers). Impulsivity traits and gambling-related cognitions are recognized as two key psychological factors in the onset and maintenance of problem gambling. To date, these constructs have been explored separately, and their joint role in determining problem gambling subtypes has received little attention. The goal of our study was to identify subgroups of gamblers based on impulsivity traits and gambling-related cognitions, and to determine whether this approach is consistent with the Pathways model. METHODS: Gamblers from the community (N=709) and treatment-seeking pathological gamblers (N=122) completed questionnaires measuring gambling habits, disordered gambling symptoms, gambling-related cognitions, and impulsivity traits. RESULTS: Cluster analyses revealed that three clusters globally aligned with the pathways proposed by Blaszczynski & Nower (2002). Two other clusters emerged: (1) impulsive gamblers without cognitive-related cognitions; and (2) gamblers without impulsivity or gambling-related cognitions. Gamblers with both heightened impulsive traits and gambling-related cognitions had more severe problem gambling symptoms. CONCLUSION: We successfully identified, based on an a priori theoretical framework, different subtypes of gamblers that varied in terms of problem gambling symptoms and clinical status. The diversity of the cluster profiles supports the development of personalized prevention strategies and psychological interventions. [less ▲]

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See detailJoint Scheduling and Beamforming in Multicell Interference Channel:Utilizing the Channel Statistics
Alodeh, Maha UL

in IEEE conference on Wireless Communications and Signal Processing (2012, October 24)

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See detailJoint Scheduling and Precoding for Frame-Based Multigroup Multicasting in Satellite Communications
Bandi, Ashok UL; Shankar, Bhavani UL; Chatzinotas, Symeon UL et al

in Bandi, Ashok; Shankar, Bhavani; Chatzinotas, Symeon (Eds.) et al Joint Scheduling and Precoding for Frame-Based Multigroup Multicasting in Satellite Communications (2019, December 09)

Recent satellite standards enforce the coding of multiple users’ data in a frame. This transmission strategy mimics the well-known physical layer multigroup multicasting (MGMC). However, typical beam ... [more ▼]

Recent satellite standards enforce the coding of multiple users’ data in a frame. This transmission strategy mimics the well-known physical layer multigroup multicasting (MGMC). However, typical beam coverage with a large number of users and limited frame length lead to the scheduling of only a few users. Moreover, in emerging aggressive frequency reuse systems, scheduling is coupled with precoding. This is addressed in this work, through the joint design of scheduling and precoding for frame-based MGMC satellite systems. This aim is formulated as the maximization of the sum-rate under per beam power constraint and minimum SINR requirement of scheduled users. Further, a framework is proposed to transform the non-smooth SR objective with integer scheduling and nonconvex SINR constraints as a difference-of-convex problem that facilitates the joint update of scheduling and precoding. Therein, an efficient convex-concave procedure based algorithm is proposed. Finally, the gains (up to 50%) obtained by the jointed design over state-of-the-art methods is shown through Monte-Carlo simulations. [less ▲]

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See detailJoint signature of two or more systems with applications to multistate systems made up of two-state components
Marichal, Jean-Luc UL; Mathonet, Pierre; Navarro, Jorge et al

in European Journal of Operational Research (2017), 263(2), 559-570

The structure signature of a system made up of n components having continuous and i.i.d. lifetimes was defined in the eighties by Samaniego as the n-tuple whose k-th coordinate is the probability that the ... [more ▼]

The structure signature of a system made up of n components having continuous and i.i.d. lifetimes was defined in the eighties by Samaniego as the n-tuple whose k-th coordinate is the probability that the k-th component failure causes the system to fail. More recently, a bivariate version of this concept was considered as follows. The joint structure signature of a pair of systems built on a common set of components having continuous and i.i.d. lifetimes is a square matrix of order n whose (k,l)-entry is the probability that the k-th failure causes the first system to fail and the l-th failure causes the second system to fail. This concept was successfully used to derive a signature-based decomposition of the joint reliability of the two systems. In the first part of this paper we provide an explicit formula to compute the joint structure signature of two or more systems and extend this formula to the general non-i.i.d. case, assuming only that the distribution of the component lifetimes has no ties. We also provide and discuss a necessary and sufficient condition on this distribution for the joint reliability of the systems to have a signature-based decomposition. In the second part of this paper we show how our results can be efficiently applied to the investigation of the reliability and signature of multistate systems made up of two-state components. The key observation is that the structure function of such a multistate system can always be additively decomposed into a sum of classical structure functions. Considering a multistate system then reduces to considering simultaneously several two-state systems. [less ▲]

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See detailA Joint Solution for Scheduling and Precoding in Multiuser MISO Downlink Channels
Bandi, Ashok UL; Shankar, Bhavani UL; Chatzinotas, Symeon UL et al

in IEEE Transactions on Wireless Communications (2019)

Detailed reference viewed: 182 (50 UL)
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See detailJoint TOA and DOA Estimation Compliant with IEEE 802.15.4a Standard
Lagunas, Eva UL; Najar, Montse; Navarro, Monica

in IEEE International Symposium on Wireless Pervasive Computing (ISWPC), Modena, Italy, 5-7 May, 2010 (2010, May)

Detailed reference viewed: 60 (1 UL)