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See detailA TWO-STEP FEATURE EXTRACTION ALGORITHM: APPLICATION TO DEEP LEARNING FOR POINT CLOUD CLASSIFICATION
Nurunnabi, Abdul Awal Md UL; Teferle, Felix Norman UL; Laefer, Debra et al

in A TWO-STEP FEATURE EXTRACTION ALGORITHM: APPLICATION TO DEEP LEARNING FOR POINT CLOUD CLASSIFICATION (2022, March)

Most deep learning (DL) methods that are not end-to-end use several multi-scale and multi-type hand-crafted features that make the network challenging, more computationally intensive and vulnerable to ... [more ▼]

Most deep learning (DL) methods that are not end-to-end use several multi-scale and multi-type hand-crafted features that make the network challenging, more computationally intensive and vulnerable to overfitting. Furthermore, reliance on empirically-based feature dimensionality reduction may lead to misclassification. In contrast, efficient feature management can reduce storage and computational complexities, builds better classifiers, and improves overall performance. Principal Component Analysis (PCA) is a well-known dimension reduction technique that has been used for feature extraction. This paper presents a two-step PCA based feature extraction algorithm that employs a variant of feature-based PointNet (Qi et al., 2017a) for point cloud classification. This paper extends the PointNet framework for use on large-scale aerial LiDAR data, and contributes by (i) developing a new feature extraction algorithm, (ii) exploring the impact of dimensionality reduction in feature extraction, and (iii) introducing a non-end-to-end PointNet variant for per point classification in point clouds. This is demonstrated on aerial laser scanning (ALS) point clouds. The algorithm successfully reduces the dimension of the feature space without sacrificing performance, as benchmarked against the original PointNet algorithm. When tested on the well-known Vaihingen data set, the proposed algorithm achieves an Overall Accuracy (OA) of 74.64% by using 9 input vectors and 14 shape features, whereas with the same 9 input vectors and only 5PCs (principal components built by the 14 shape features) it actually achieves a higher OA of 75.36% which demonstrates the effect of efficient dimensionality reduction. [less ▲]

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See detailAmbient Backscatter Assisted Co-Existence in Aerial-IRS Wireless Networks
Solanki, Sourabh UL; Gautam, Sumit; Sharma, Shree Krishna et al

in IEEE Open Journal of the Communications Society (2022), 3

Ambient backscatter communication (AmBC) is an emerging technology that has the potential to offer spectral- and energy-efficient solutions for the next generation wireless communications networks ... [more ▼]

Ambient backscatter communication (AmBC) is an emerging technology that has the potential to offer spectral- and energy-efficient solutions for the next generation wireless communications networks, especially for the Internet of Things (IoT). Intelligent reflecting surfaces (IRSs) are also perceived to be an integral part of the beyond 5G systems to complement the traditional relaying scheme. To this end, this paper proposes a novel system design that enables the co-existence of a backscattering secondary system with the legacy primary system. This co-existence is primarily driven by leveraging the AmBC technique in IRS-assisted unmanned aerial vehicle (UAV) networks. More specifically, an aerial-IRS mounted on a UAV is considered to be employed for cooperatively relaying the transmitted signal from a terrestrial primary source node to a user equipment on the ground. Meanwhile, capitalizing on the AmBC technology, a backscatter capable terrestrial secondary node transmits its information to a terrestrial secondary receiver by modulating and backscattering the ambient relayed radio frequency signals from the UAV-IRS. We comprehensively analyze the performance of the proposed design framework with co-existing systems by deriving the outage probability and ergodic spectral efficiency expressions. Moreover, we also investigate the asymptotic behaviour of outage performance in high transmit power regimes for both primary and secondary systems. Importantly, we analyze the performance of the primary system by considering two different scenarios i.e., optimal phase shifts design and random phase shifting at IRS. Finally, based on the analytical performance assessment, we present numerical results to provide various useful insights and also provide simulation results to corroborate the derived theoretical results. [less ▲]

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See detailHeidelberger Kommentar Medienstaatsvertrag Jugendmedienschutzstaatsvertrag
Cole, Mark David UL; Hartstein, Reinhard; Ring, Wolf-Dieter et al

Book published by C.F. Müller - 90. AL (2022)

Im September 2020 ist es soweit: Der neue Medienstaatsvertrag löst den bisherigen Rundfunkstaatsvertrag ab. Er bedeutet nicht weniger als eine umfassende Neuregulierung der elektronischen Medien. Auch die ... [more ▼]

Im September 2020 ist es soweit: Der neue Medienstaatsvertrag löst den bisherigen Rundfunkstaatsvertrag ab. Er bedeutet nicht weniger als eine umfassende Neuregulierung der elektronischen Medien. Auch die Vorschriften zur Aufsicht erfahren umfangreiche Neuregelungen. Insgesamt lassen sich im Vergleich zum Rundfunkstaatsvertrag erhebliche Änderungen sowohl in der Systematik als auch in vielen Details verzeichnen. Der Medienstaatsvertrag trägt damit technischen Entwicklungen ebenso Rechnung wie der Umsetzung von neuen Vorgaben auf unionaler Ebene. Überarbeitet und geändert wurden Regelungen zum Rundfunkbegriff- und Zulassungsvorschriften sowie die Plattformregulierung. Teilweise völlig neu oder mindestens erheblich geändert sind die Abschnitte zu neuen Medienformen und -plattformarten, zu "Medienintermediären", "Benutzeroberflächen" und "Video-Sharing-Diensten". Unser Standardwerk zum bisherigen Rundfunkstaatsvertrag sowie Jugendmedienschutzstaatsvertrag trägt diesen weitreichenden Änderungen Rechnung und wird zum Heidelberger Kommentar Medienstaatsvertrag Jugendmedienschutz-Staatsvertrag. In gewohnter Qualität und Expertise - Herausgeber und Autoren sind namhafte Experten aus der deutschen Medienlandschaft - wird die gesamte historische Entwicklung des föderal vereinbarten Rundfunk- und Telemedienrechts einschließlich des Jugendmedienschutzrechts und der europäischen Entwicklungen berücksichtigt und es wird eine vollständige Informationsquelle zu verfassungsrechtlichen, einfachgesetzlichen und praktischen Streitfragen geboten. Dabei enthält der Kommentar neben dem Text der Staatsverträge sämtliche relevanten begleitenden Texte wie die amtlichen Begründungen, die Ratifizierungsgesetze sowie Dokumente aus dem Europarecht und von Landesmedienanstalten, Rundfunkanstalten und Selbstkontrollorganisationen. Ausführungen zur Entstehungsgeschichte geben wertvolle Erkenntnisse zu Hintergründen des Medienstaatsvertrags. Übersichtsbeiträge zur relevanten Verfassungsrechtsprechung, zu den einschlägigen Rechtsgrundlagen und zu den europäischen Entwicklungen bilden die Basis für die ausführlichen Einzelkommentierungen zum Medienstaatsvertrag und Jugendmedienschutzstaatsvertrag. Dabei sind durchgängig die europarechtlichen Vorgaben durch die EU-Richtlinie über audiovisuelle Mediendienste (AVMD) berücksichtigt. [less ▲]

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See detailInteractive Narratives and Transmedia Storytelling: An Insight on Digital Exhibitions
Camarda, Sandra UL

in Sonnabend, Gaby; Thewes, Guy (Eds.) Narratives in History Museums – Reflections and Perspectives (2022, March)

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See detailCahiers de fiscalité luxembourgeoise et européenne - 2022/1
Chaouche, Fatima; Sinnig, Julia UL

in Cahiers de fiscalité luxembourgeoise et européenne (2022), 1(1), 201

Les Cahiers de fiscalité luxembourgeoise et européenne offrent une analyse rigoureuse et thématique du droit fiscal luxembourgeois. Associant les exigences de la recherche scientifique à la réalité de la ... [more ▼]

Les Cahiers de fiscalité luxembourgeoise et européenne offrent une analyse rigoureuse et thématique du droit fiscal luxembourgeois. Associant les exigences de la recherche scientifique à la réalité de la pratique administrative luxembourgeoise, les Cahiers proposent deux fois par an une sélection d'analyses doctrinales rédigées par des experts luxembourgeois et étrangers. Chaque numéro des Cahiers se fait également le reflet d'une analyse systémique de la jurisprudence fiscale la plus récente au niveau national - contributions directes (juridictions administratives) et fiscalité indirecte (juridictions judiciaires) - et au niveau supranational (CJUE, CEDH). La recherche en droit fiscal luxembourgeois étant au coeur de ce projet collectif éditorial, les Cahiers publient régulièrement des actes de colloques, des extraits de thèses de doctorat récemment soutenues et un travail pluriannuel de rédaction de commentaires de la loi générale des impôts (Abgabenordnung). [less ▲]

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See detailTaxation, data and destination - An analysis of destination-based taxation from the perspective of tax principles and data protection regulation
Sinnig, Julia UL

in Cahiers de fiscalité luxembourgeoise et européenne (2022), 1(1), 183-195

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See detailAre Value-Added Scores Stable Enough for High-Stakes Decisions?
Emslander, Valentin UL; Levy, Jessica UL; Scherer, Ronny et al

Scientific Conference (2022, March)

Theoretical Background: Can we quantify the effectiveness of a teacher or a school with a single number? Researchers in the field of value-added (VA) models may argue just that (e.g., Chetty et al., 2014 ... [more ▼]

Theoretical Background: Can we quantify the effectiveness of a teacher or a school with a single number? Researchers in the field of value-added (VA) models may argue just that (e.g., Chetty et al., 2014; Kane et al., 2013). VA models are widely used for accountability purposes in education and quantify the value a teacher or a school adds to their students’ achievement. For this purpose, these models predict achievement over time and attempt to control for factors that cannot be influenced by schools or teachers (i.e., sociodemographic & sociocultural background). Following this logic, what is left must be due to teacher or school differences (see, e.g., Braun, 2005). To utilize VA models for high-stakes decision-making (e.g., teachers’ tenure, the allocation of funding), these models would need to be highly stable over time. School-level stability over time, however, has hardly been researched at all and the resulting findings are mixed, with some studies indicating high stability of school VA scores over time (Ferrão, 2012; Thomas et al., 2007) and others reporting a lack of stability (e.g., Gorard et al., 2013; Perry, 2016). Furthermore, as there is no consensus on which variables to use as independent or dependent variables in VA models (Everson, 2017; Levy et al., 2019), the stability of VA could vary between different outcome measures (e.g., language or mathematics). If VA models lack stability over time and across outcome measures, their use as the primary information for high-stakes decision-making is in question, and the inferences drawn from them could be compromised. Questions: With these uncertainties in mind, we examine the stability of school VA model scores over time and investigate the differences between language and mathematics achievement as outcome variables. Additionally, we demonstrate the real-life implications of (in)stable VA scores for single schools and point out an alternative, more constructive use of school VA models in educational research. Method: To study the stability of VA scores on school level over time and across outcomes, we drew on a sample of 146 primary schools, using representative longitudinal data from the standardized achievement tests of the Luxembourg School Monitoring Programme (LUCET, 2021). These schools included a heterogeneous and multilingual sample of 7016 students. To determine the stability of VA scores in the subject of mathematics and in languages over time, we based our analysis on two longitudinal datasets (from 2015 to 2017 and from 2017 to 2019, respectively) and generated two VA scores per dataset, one for language and one for mathematics achievement. We further analyzed how many schools displayed stable VA scores in the respective outcomes over two years, and compared the rank correlations of VA scores between language and mathematics achievement as an outcome variable. Results and Their Significance: Only 34-38 % of the schools showed stable VA scores from grade 1 to 3 with moderate rank correlations of r = .37 with language and r = .34 with mathematics achievement. We therefore discourage using VA models as the only information for high-stakes educational decisions. Nonetheless, we argue that VA models could be employed to find genuinely effective teaching or school practices—especially in heterogeneous student populations, such as Luxembourg, in which educational disparities are an important topic already in primary school (Hoffmann et al., 2018). Consequently, we contrast the school climate and instructional quality, which might be a driver of the differences between schools with stable high vs. low VA scores. Literature Braun, H. (2005). Using student progress to evaluate teachers: A primer on value-added models. Educational Testing Service. Chetty, R., Friedman, J. N., & Rockoff, J. E. (2014). Measuring the impacts of teachers I: Evaluating bias in teacher value-added estimates. American Economic Review, 104(9), 2593–2632. https://doi.org/10.1257/aer.104.9.2593 Everson, K. C. (2017). Value-added modeling and educational accountability: Are we answering the real questions? Review of Educational Research, 87(1), 35–70. https://doi.org/10.3102/0034654316637199 Ferrão, M. E. (2012). On the stability of value added indicators. Quality & Quantity, 46(2), 627–637. https://doi.org/10.1007/s11135-010-9417-6 Gorard, S., Hordosy, R., & Siddiqui, N. (2013). How unstable are “school effects” assessed by a value-added technique? International Education Studies, 6(1), 1–9. https://doi.org/10.5539/ies.v6n1p1 Kane, T. J., McCaffrey, D. F., Miller, T., & Staiger, D. O. (2013). Have We Identified Effective Teachers? Validating Measures of Effective Teaching Using Random Assignment. Research Paper. MET Project. Bill & Melinda Gates Foundation. https://files.eric.ed.gov/fulltext/ED540959.pdf Levy, J., Brunner, M., Keller, U., & Fischbach, A. (2019). Methodological issues in value-added modeling: An international review from 26 countries. Educational Assessment, Evaluation and Accountability, 31(3), 257–287. https://doi.org/10.1007/s11092-019-09303-w LUCET. (2021). Épreuves Standardisées (ÉpStan). https://epstan.lu Perry, T. (2016). English value-added measures: Examining the limitations of school performance measurement. British Educational Research Journal, 42(6), 1056–1080. https://doi.org/10.1002/berj.3247 Thomas, S., Peng, W. J., & Gray, J. (2007). Modelling patterns of improvement over time: Value added trends in English secondary school performance across ten cohorts. Oxford Review of Education, 33(3), 261–295. https://doi.org/10.1080/03054980701366116 [less ▲]

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See detailDynamic Bandwidth Allocation and Precoding Design for Highly-Loaded Multiuser MISO in Beyond 5G Networks
Vu, Thang Xuan UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in IEEE Transactions on Wireless Communications (2022), 21(3), 1794-1805

Multiuser techniques play a central role in the fifth-generation (5G) and beyond 5G (B5G) wireless networks that exploit spatial diversity to serve multiple users simultaneously in the same frequency ... [more ▼]

Multiuser techniques play a central role in the fifth-generation (5G) and beyond 5G (B5G) wireless networks that exploit spatial diversity to serve multiple users simultaneously in the same frequency resource. It is well known that a multi-antenna base station (BS) can efficiently serve a number of users not exceeding the number of antennas at the BS via precoding design. However, when there are more users than the number of antennas at the BS, conventional precoding design methods perform poorly because inter-user interference cannot be efficiently eliminated. In this paper, we investigate the performance of a highly-loaded multiuser system in which a BS simultaneously serves a number of users that is larger than the number of antennas. We propose a dynamic bandwidth allocation and precoding design framework and apply it to two important problems in multiuser systems: i) User fairness maximization and ii) Transmit power minimization, both subject to predefined quality of service (QoS) requirements. The premise of the proposed framework is to dynamically assign orthogonal frequency channels to different user groups and carefully design the precoding vectors within every user group. Since the formulated problems are non-convex, we propose two iterative algorithms based on successive convex approximations (SCA), whose convergence is theoretically guaranteed. Furthermore, we propose a low-complexity user grouping policy based on the singular value decomposition (SVD) to further improve the system performance. Finally, we demonstrate via numerical results that the proposed framework significantly outperforms existing designs in the literature. [less ▲]

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See detailThe Law of the Economic and Monetary Union: Complementing, Adapting or Transforming the EU Legal Order?
Tuori, Klaus UL; Losada, Fernando

in European Papers - A Journal on Law and Integration (2022), Vol. 6(3), 1367-1521

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See detailWaveform Design for Joint Radar-Communications with Low Complexity Analog Components
Kaushik, Aryan; Arora, Aakash; Tsinos,Christos et al

Poster (2022, March)

In this paper, we aim to design an efficient and low hardware complexity based dual-function multiple-input multiple-output (MIMO) joint radar-communication (JRC) system. It is implemented via a low ... [more ▼]

In this paper, we aim to design an efficient and low hardware complexity based dual-function multiple-input multiple-output (MIMO) joint radar-communication (JRC) system. It is implemented via a low complexity analog architecture, constituted by a phase shifting network and variable gain amplifier. The proposed system exploits the multiple antenna transmitter for the simultaneous communication with multiple downlink users and radar target detection. The transmit waveform of the proposed JRC system is designed to minimize the downlink multi-user interference such that the desired radar beampattern is achieved and the architecture specific constraints are satisfied. The resulting optimization problem is non-convex and in general difficult to solve. We propose an efficient algorithmic solution based on the primal-dual framework. The numerical results show the effectiveness of the proposed approach. [less ▲]

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See detailIntelligent Reflecting Surface-assisted MU-MISOSystems with Imperfect Hardware: ChannelEstimation and Beamforming Design
Papazafeiropoulos, Anastasios; Pan, Cunhua; Kourtessis, Pandelis et al

in IEEE Transactions on Wireless Communications (2022), 21(3), 2077-2092

Intelligent reflecting surface (IRS), consisting of low-cost passive elements, is a promising technology for improvingthe spectral and energy efficiency of the fifth-generation (5G)and beyond networks. It ... [more ▼]

Intelligent reflecting surface (IRS), consisting of low-cost passive elements, is a promising technology for improvingthe spectral and energy efficiency of the fifth-generation (5G)and beyond networks. It is also noteworthy that an IRS canshape the reflected signal propagation. Most works in IRS-assisted systems have ignored the impact of the inevitable residualhardware impairments (HWIs) at both the transceiver hardwareand the IRS while any relevant works have addressed only simplescenarios, e.g., with single-antenna network nodes and/or withouttaking the randomness of phase noise at the IRS into account.In this work, we aim at filling up this gap by considering ageneral IRS-assisted multi-user (MU) multiple-input single-output(MISO) system with imperfect channel state information (CSI)and correlated Rayleigh fading. In parallel, we present a generalcomputationally efficient methodology for IRS reflect beamforming(RB) optimization. Specifically, we introduce an advantageouschannel estimation (CE) method for such systems accounting forthe HWIs. Moreover, we derive the uplink achievable spectralefficiency (SE) with maximal-ratio combining (MRC) receiver,displaying three significant advantages being: 1) its closed-formexpression, 2) its dependence only on large-scale statistics, and3) its low training overhead. Notably, by exploiting the first twobenefits, we achieve to perform optimization with respect to thethat can take place only at every several coherence intervals,and thus, reduces significantly the computational cost comparedto other methods which require frequent phase optimization.Among the insightful observations, we highlight that uncorrelatedRayleigh fading does not allow optimization of the SE, whichmakes the application of an IRS ineffective. Also, in the case thatthe phase drifts, describing the distortion of the phases in theRBM, are uniformly distributed, the presence of an IRS providesno advantage. The analytical results outperform previous worksand are verified by Monte-Carlo (MC) simulations. [less ▲]

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See detailIntegrating Macroeconomics into the EU Single Legal Order: The Role of Financial Stability in Post-Crisis Europe
Tuori, Klaus UL; Losada, Fernando

in European Papers (2022), Vol. 6(3 /2021), 1367-1396

This article follows the trajectory of the EU legal order, from its inception to its current stage, by focusing on the transformations it has experienced resulting from its increasing interaction with ... [more ▼]

This article follows the trajectory of the EU legal order, from its inception to its current stage, by focusing on the transformations it has experienced resulting from its increasing interaction with macroeconomics. When the Court of Justice declared that a new legal order resulted from the provisions of the Treaty of Rome, its interpretation stemmed from a coherent understanding of the institutional form (indirect administration) and substantive content (microeconomic integra-tion) of European integration. The addition of the macroeconomic layer of integration, with its own institutional form (integrated administration and open method of coordination) but still broadly subject to the same legal order, resulted into a less consistent whole. The crises the Union faced during the last decade tested the resistance of these structures and, although the Court has been consistently interpreting EU law according to the same procedures and tech-niques without radical deviations, the irruption of financial stability as macroeconomic impera-tive has rearranged the equilibrium in integration. Now we can argue that institutional form, substantive content and legal order of European integration are again realigned, but instead of resulting from the provisions of the Treaties and from placing the legal rationality of law at the core of the system, financial stability is the rationale coherently arranging them together. The consequences of this rearrangement for the EU legal order are the object of study of this spe-cial issue. [less ▲]

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See detailSupercurrent-enabled Andreev reflection in a chiral quantum Hall edge state
Michelsen, Andreas; Recher, Patrik; Braunecker, Bernd et al

E-print/Working paper (2022)

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See detailRefracting RIS-Aided Hybrid Satellite-Terrestrial Relay Networks: Joint Beamforming Design and Optimization
Lin, Zhi; Niu, Hehao; An, Kang et al

in IEEE Transactions on Aerospace and Electronic Systems (2022)

Reconfigurable intelligent surface (RIS) has been viewed as a promising solution in constructing reconfigurable radio environment of the propagation channel and boosting the received signal power by ... [more ▼]

Reconfigurable intelligent surface (RIS) has been viewed as a promising solution in constructing reconfigurable radio environment of the propagation channel and boosting the received signal power by smartly coordinating the passive elements’ phase shifts at the RIS. Inspired by this emerging technique, this article focuses on joint beamforming design and optimization for RIS-aided hybrid satellite-terrestrial relay networks, where the links from the satellite and base station (BS) to multiple users are blocked. Specifically, a refracting RIS cooperates with a BS, where the latter operates as a half-duplex decode-and-forward relay, in order to strengthen the desired satellite signals at the blocked users. Considering the limited onboard power resource, the design objective is to minimize the total transmit power of both the satellite and BS while guaranteeing the rate requirements of users. Since the optimized beamforming weight vectors at the satellite and BS, and phase shifters at the RIS are coupled, leading to a mathematically intractable optimization problem, we propose an alternating optimization scheme by utilizing singular value decomposition and uplink–downlink duality to optimize beamforming weight vectors, and using Taylor expansion and penalty function methods to optimize phase shifters iteratively. Finally, simulation results are provided to verify the superiority of the proposed scheme compared to the benchmark schemes [less ▲]

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See detailModal characterisation of simulation relations in probabilistic concurrent games
Zhang, Chenyi; Pang, Jun UL

in Science of Computer Programming (2022), 215

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See detailLa protection des données personnelles par le droit européen de la consommation
Poillot, Elise UL

in Combet, Mathieu (Ed.) Le droit européen de la consommation au XXIe siècle (2022)

L'article envisage la façon dont le droit de la protection des consommateurs protège les données personnelles des consommateurs et s'arrête notamment sur les difficultés posées par l'articulation du RGPD ... [more ▼]

L'article envisage la façon dont le droit de la protection des consommateurs protège les données personnelles des consommateurs et s'arrête notamment sur les difficultés posées par l'articulation du RGPD avec les textes de droit de la consommation [less ▲]

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See detailPanorama de droit de la consommation 2021
Poillot, Elise UL; Aubry, Hélène; Sauphanoir-Brouillaud, Natacha

in Recueil Dalloz (2022)