Not just a "second order" problem in a wider economic crisis: systemic challenges for the global trading system

Reform of the multilateral trade regime is not simply a second order problem within a wider economic crisis. The completion of the Doha Round may be a second order question but the global trade regime faces a series of broader systemic challenges beyond the completion of the current negotiations. This paper identifies five challenges: (i) a marked reduction in popular support for open markets in major OECD countries; (ii) the stalling of a transition from one global economic equilibrium to another; (iii) a lack of clarity and agreement on the agenda and objectives for the WTO as we move deeper into the 21st century; (iv) the demand for fairness and justice in the governance of the WTO—the 'legitimacy' question and (v) the rise of regional preferentialism as a challenge to multilateralism. Failure to address these challenges will represent not only a fundamental question for the future of the WTO as the guarantor of the norms and rules of the global trade regime specifically, but also the ability to establish greater coherence in global economic governance overall when its need is arguably greater than at any time since the depression years of the 20th century inter-war period

III-V Solar Cells

III-V materials show a wide range of gaps making them ideal for the design of high efficiency solar cells. This chapter reviews relevant growth methods and material properties of these materials and discusses methods of combining heterogeneous materials, demonstrating the flexibility of design possible with these materials. The fundamental loss mechanisms of solar cells are analysed and quantified as a prelude to analysing high efficiency cell designs in single, tandem, and triple junction solar cells. The detailed analysis of loss mechanisms is used to obtain understanding of the limiting behaviour of these designs, and show that bulk cells remain dominated by non-radiative losses despite unity ideality factors. To conclude, this is contrasted with the operating regime of nanostructured solar cells which can be shown to operate in a radiatively dominated mode, and which therefore approach ideal solar cell efficiency limits.Comment: Draft of chapter in Materials Challenges: Inorganic Photovoltaic Solar Energy - RSC Energy and Environment Series v. 1

Unleashing the power of multi-agent voting teams

Teams of voting agents have great potential in finding optimal solutions. However, there are fundamental challenges to effectively use such teams: (i) selecting agents; (ii) aggregating opinions; (iii) assessing performance. I address all these challenges, with theoretical and experimental contributions

Accelerating Action Against Child Labour

[Excerpt] The focus of this third Global Report on child labour under the follow-up to the ILO Declaration on Fundamental Principles and Rights at Work is about honouring the commitments made in 2006 with the adoption of a Global Action Plan. The Action Plan set out time-bound targets for the elimination of child labour. Important obligations and commitments were entered into by ILO constituents. Four years is a short time to ensure major change, but it does, however, permit the Organization to take stock and gauge progress. In particular we need to know whether the world is on track to meeting the target of eliminating all the worst forms of child labour by 2016. To this end, this Global Report adopts the same four-part structure as the two previous Reports. Part I presents a dynamic global picture, updating global trends introduced in the 2006 Global Report and setting out progress in the ratification of ILO standards. Part II reviews the progress made in implementing the Global Action Plan. From this review, Part III examines key challenges and gaps that remain and how these can be addressed. Finally, Part IV sets out an agenda to accelerate progress towards meeting the 2016 target

Broadband Angular Selectivity of Light at the Nanoscale: Progress, Applications and Outlook

Humankind has long endeavored to control the propagation direction of light. Since time immemorial, shades, lenses and mirrors have been used to control the flow of light. In modern society, with the rapid development of nanotechnology, the control of light is moving toward devices at micrometer and even nanometer scales. At such scales, traditional devices based on geometrical optics reach their fundamental direction limits and cease to work. Nano photonics, on the other hand, has attracted wide attention from researchers, especially in the last decade, due to its ability to manipulate light at the nanoscale. This review focuses on the nano photonics systems that aim to select light based on its propagation direction. In the first half of this review, we survey the literature and the current state of the art focused on enabling optical broadband angular selectivity. The mechanisms we review can be classified into three main categories: (i) microscale geometrical optics, (ii) multilayer birefringent materials and (iii) Brewster modes in plasmonic systems, photonic crystals and metamaterials. In the second half, we present two categories of potential applications for broadband angularly selective systems. The first category aims at enhancing the efficiency of solar energy harvesting, through photovoltaic process or solar thermal process. The second category aims at enhancing light extracting efficiency and detection sensitivity. Finally, we discuss the most prominent challenges in broadband angular selectivity and some prospects on how to solve these challenges.Comment: 14 page, 11 figure

Tree-based Coarsening and Partitioning of Complex Networks

Many applications produce massive complex networks whose analysis would benefit from parallel processing. Parallel algorithms, in turn, often require a suitable network partition. For solving optimization tasks such as graph partitioning on large networks, multilevel methods are preferred in practice. Yet, complex networks pose challenges to established multilevel algorithms, in particular to their coarsening phase. One way to specify a (recursive) coarsening of a graph is to rate its edges and then contract the edges as prioritized by the rating. In this paper we (i) define weights for the edges of a network that express the edges' importance for connectivity, (ii) compute a minimum weight spanning tree $T^m$ with respect to these weights, and (iii) rate the network edges based on the conductance values of $T^m$'s fundamental cuts. To this end, we also (iv) develop the first optimal linear-time algorithm to compute the conductance values of \emph{all} fundamental cuts of a given spanning tree. We integrate the new edge rating into a leading multilevel graph partitioner and equip the latter with a new greedy postprocessing for optimizing the maximum communication volume (MCV). Experiments on bipartitioning frequently used benchmark networks show that the postprocessing already reduces MCV by 11.3%. Our new edge rating further reduces MCV by 10.3% compared to the previously best rating with the postprocessing in place for both ratings. In total, with a modest increase in running time, our new approach reduces the MCV of complex network partitions by 20.4%