Fast Dynamic Pointer Following via Link-Cut Trees

In this paper, we study the problem of fast dynamic pointer following: given a directed graph $G$ where each vertex has outdegree $1$, efficiently support the operations of i) changing the outgoing edge of any vertex, and ii) find the vertex $k$ vertices `after' a given vertex. We exhibit a solution to this problem based on link-cut trees that requires $O(\lg n)$ time per operation, and prove that this is optimal in the cell-probe complexity model.Comment: 7 page

APPLICATION OF BAMBOO FOR FLEXURAL AND SHEAR REINFORCEMENT IN CONCRETE BEAMS

As the developing world is industrializing and people migrate to cities, the need for infrastructure is growing quickly and concrete has become one of the most widely used construction materials. One poor construction practice observed widely across the developing world is the minimal use of reinforcement for concrete structures due to the high cost of steel. As a low-cost, high-performance material with good mechanical properties, bamboo has been investigated as an alternative to steel for reinforcing concrete. The goal of this research is to add to the knowledge base of bamboo reinforced concrete (BRC) by investigating a unique stirrup design and testing the lap-splicing of flexural bamboo reinforcement in concrete beams. Component tests on the mechanical properties of Moso bamboo (Phyllostachys edulis) were performed, including tensile tests and pull-out tests. The results of the component tests were used to design and construct 13 BRC beams which were tested under monotonic gravity loading in 3 and 4-point bending tests. Three types of beams were designed and tested, including shear controlled, flexure controlled, and lap-spliced flexure controlled beams. The test results indicated that bamboo stirrups increased unreinforced concrete beam shear capacities by up to 259%. The flexural bamboo increased beam capacities by up to 242% with an optimal reinforcement ratio of up to 3.9%, assuming sufficient shear capacity. Limitations of the bamboo reinforcement included water absorption as well as poor bonding capability to the concrete. The test results show that bamboo is a viable alternative to steel as tensile reinforcement for concrete as it increases the ultimate capacity of the concrete, allows for high deflections and cracks, and provides warning of impending structural failure

Two theories of fairness

In A Theory of Justice, John Rawls argues that justice is to be understood as fairness. The theory of justice as fairness is an ethical theory which argues that broad principles are able to capture the nature of what constitutes a just society. Rawls argues that all that is required for a society to be just is for it to be fair. A just society is one which has institutions which protect individual rights and liberties of all citizens and has a pattern of distribution of resources. Rawls\u27 institutional approach to justice has one problem. Rawls\u27 theory of justice as fairness seeks to ignore the issue of moral desert. According to Rawls, a just society is not necessarily responsible for providing people what is intuitively considered their just deserts. Justice is an attribute of society and not individuals. Rawls\u27 treatment of the issue of moral deserts reveals that his theory of justice as fairness is actually two theories of justice. The first is concerned with the hypothetical structure of an ideal society. The second is his theory of just institutions. In the ideal hypothetical society, Rawls can ignore the issue of desert. In actual social institutions, the issue of desert is more problematic. The issue of desert reveals that Rawls is committed to two theories of justice. The hypothetical theory does not need a theory of desert. The instantiation of the theory, as found in institutions, does require a working conception of desert

From Scalability to Subsidiarity in Addressing Online Harm

Large social media platforms are generally designed for scalability—the ambition to increase in size without a fundamental change in form. This means that to address harm among users, they favor automated moderation wherever possible and typically apply a uniform set of rules. This article contrasts scalability with restorative and transformative justice approaches to harm, which are usually context-sensitive, relational, and individualized. We argue that subsidiarity—the principle that local social units should have meaningful autonomy within larger systems—might foster the balance between context and scale that is needed for improving responses to harm

Cooperative Enterprise as an Antimonopoly Strategy

After decades of neglect, antitrust is once again a topic of public debate. Proponents of reviving antitrust have called for abandoning the narrow consumer welfare objective and embracing a broader set of objectives. One essential element that has been overlooked thus far is the ownership structure of the firm itself. The dominant model of investor-owned business and associated philosophy of shareholder wealth maximization exacerbate the pernicious effects of market power. In contrast, cooperative ownership models can mitigate the effects of monopoly and oligopoly, as well as advance the interests of consumers, workers, small business owners, and citizens. The promotion of fair competition among large firms should be paired with support for democratic cooperation within firms. Antitrust law has had a complicated history and relationship with cooperative enterprise. Corporations threatened by cooperatives have used the antitrust laws to frustrate the growth of these alternative businesses. To insulate cooperatives from the antitrust threat, Congress has enacted exemptions to protect cooperative entities, notably a general immunity for farm cooperatives in the 1922 Capper-Volstead Act. As part of an agenda to tame corporate monopoly, all three branches of the federal government and the states should revisit these ideas and seek to protect and enable the cooperative model across the economy. Although protections that farmers fought for a century ago may seem obsolete in an era of big-box retail and online platforms, matters of ownership design have at least as much relevance today and should be a part of the antimonopoly arsenal