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This paper introduces the concept of a non-uniform constellation (NUC) in contrast to conventional uniform quadrature-amplitude modulation (QAM) constellations. Such constellations provide additional shaping gain, which allows reception at lower signal-to-noise ratios. ATSC3.0 will be the first major broadcasting standard, which completely uses NUCs due to their outstanding properties. We will consider different kinds of NUCs and describe their performance: 2-D NUCs provide more shaping gain at the cost of higher demapping complexity, while 1-D NUCs allow low-complexity demapping at slightly lower shaping gains. These NUCs are well suited for very large constellations sizes, such as 1k and 4k QAM.

In this paper, we introduce the overview and detailed structure of low-density parity-check (LDPC) codes, which are adopted for the physical layer standard of Advanced Television Systems Committee (ATSC) 3.0. As one of the features to mitigate channel errors efficiently, LDPC codes are used as a main part of forward error correction scheme within the bit interleaved coded modulation chain. This paper presents two different structures of LDPC codes in the ATSC 3.0 standard: 1) irregular repeat accumulate structure and 2) multi-edge type structure. After the detailed encoding methods for the two structures are introduced, the performance results including comparison studies with other broadcasting standards such as DVB-T2 and DVB-S2 are shown.

The physical layer [layer-1 (L1)] signaling (L1 signaling) of Advanced Television Systems Committee (ATSC) 3.0 is studied. In the new digital broadcasting system, ATSC 3.0, L1 signaling is designed to be more efficient but still robust compared with preceding standards such as DVB-T2. We introduce the error protection scheme of ATSC 3.0 in detail. Especially advanced methods newly employed in ATSC 3.0 are investigated with regard to its purpose and benefit in comparison to conventional DVB-T2.

Addressing human impact on the environment by focusing on shared everyday practices, rather than just individual behavior is an approach that shows promise. However, it can be challenging to put this approach into concrete use, especially in teams unfamiliar with the practice orientation. To support the practice approach, we introduce the Contextual Wheel of Practice (COWOP), a framework that can: 1) help researchers and designers to better understand practices, 2) design effective interventions, and 3) facilitate collaboration between team members from different disciplines, who may not be familiar with the practice orientation. We describe how COWOP was developed, and our experiences using COWOP in three different cases. We then position COWOP as part of the "turn to practice" in HCI, and discuss how it can be useful to HCI researchers and be applied in domains beyond sustainability, such as healthcare and privacy.

The question "What to Study in HCI" has two parts. First it asks how HCI researchers think about the research challenges they tackle: how do they decide what problems to engage with and how to study them? Second, the question also asks what is the subject of HCI: which challenges should researchers address and, ultimately, what makes us unique as a discipline? While there have been intermittent discussions on this topic in HCI, the present workshop emphasizes this question and explore some possible answers among a group of seasoned researchers. One reason is our belief that researchers can benefit from addressing these questions so as to develop their practical understanding (e.g., "tricks of the trade") of how to tackle the complexity of selecting "what to study". Second, we argue that researchers can benefit from thinking about the epistemological grounds upon which they base their everyday work, that is, thinking about what HCI is. The workshop results in publicly available key readings and position papers on "What to Study in HCI".

We present BaseLase, an interactive laser projected focus + context floor display. In order to provide a transportable system that works in areas where there are no ceilings, we provide an integrated unit (1.3m height) that stands on the floor. One unsolved challenge for laser projectors is to cover large projection areas while providing high resolution at the same time. Our focus + context laser projector solves this problem. BaseLase can cover a large context area in low resolution, while providing three movable high-resolution focus spots. We provide a convex mirror design that enables the laser to reach a large area (75m2) with low resolution while decreasing the beam divergence compared to spherical or parabolic mirrors. This hyperboloidal mirror shape approximately equalizes the point size on the floor independent from the projected location. We propose to add a number of planar mirrors on pan-tilt units to create dynamic zones of high resolution that can adjust to the user behavior. We provide example applications for BaseLase and report on user experience in preliminary trials.

This paper discusses three cases where design was carried out at the intersection between public sector and citizen communities. Based on three dominant traditions meeting there--public (municipal) decision-making, Web 2.0 and participatory design--we identify challenges and solutions regarding participation and engagement of municipal workers and citizens. While this intersection is exactly where a new form of democratic participation could develop, the three traditions were, nonetheless, far from easily combined in the specific cases. The challenges that we have identified are to: Identify win-win situations, rather than to maximize participation; to work with motivation for long-term projects across municipality and communities; to identify and work with early movers, and not just representative citizens; and to create space for local municipal agencies to develop bottom-up technological solutions. The multiplicity of co-existing traditions of involvement need more focus in the future development of participatory design.