The model checking problem for intuitionistic propositional logic with one variable is AC1-complete

We show that the model checking problem for intuitionistic propositional logic with one variable is complete for logspace-uniform AC1. As basic tool we use the connection between intuitionistic logic and Heyting algebra, and investigate its complexity theoretical aspects. For superintuitionistic logics with one variable, we obtain NC1-completeness for the model checking problem.Comment: A preliminary version of this work was presented at STACS 2011. 19 pages, 3 figure

Market Based Approaches for Dynamic Spectrum Assignment

Abstract—Much of the technical literature on spectrum sharing has been on developing technologies and systems for non-cooperative) opportunistic use. In this paper, we situate this approach to secondary spectrum use in a broader context, one that includes cooperative approaches to Dynamic Spectrum Access (DSA). In this paper, we introduce readers to this broader approach to DSA by contrasting it with non-cooperative sharing (opportunistic use), surveying relevant literature, and suggesting future directions for researc

Can Unlicensed Bands Be Used by Unlicensed Usage?

Since their introduction, unlicensed ISM bands have resulted in a wide range of new wireless devices and services. It is fair to say that the success of ISM was an important factor in the opening of the TV white space for unlicensed access. Further bands (e.g., 3550-3650 MHz) are being studied to support unlicensed access. Expansion of the unlicensed bands may well address one of the principle disadvantages of unlicensed (variable quality of service) which could result in a vibrant new group companies providing innovative services and better prices. However, given that many commercial mobile telephone operators are relying heavily on the unlicensed bands to manage growth in data traffic through the “offloading” strategy, the promise of these bands may be more limited than might otherwise be expected (Musey, 2013).\ud \ud Wireless data traffic has exploded in the past several years due to more capable devices and faster network technologies. While there is some debate on the trajectory of data growth, some notable reports include AT&T, which reported data growth of over 5000% from 2008 to 2010 and Cisco, who predicted that mobile data traffic will grow to 6.3 exabytes per month in average by 2015 (Hu, 2012). Although the data traffic increased dramatically, relatively little new spectrum for mobile operators has come online in the last several years; further, the “flat-rate” pricing strategy has led to declining Average Revenue Per User (ARPU) for the mobile operators. Their challenge, then, is how to satisfy the service demand with acceptable additional expenditures on infrastructure and spectrum utilization.\ud \ud A common response to this challenge has been to offload data traffic onto unlicensed (usually WiFi) networks. This can be accomplished either by establishing infrastructure (WiFi hotspots) or to use existing private networks. This phenomenon leads to two potential risks for spectrum entrants: (1) the use of offloading may overwhelm unlicensed spectrum and leave little access opportunities for newcomers; (2) the intensity of the traffic may increase interference and degrade innovative services.\ud \ud Consequently, opening more unlicensed frequency bands alone may not necessarily lead to more unlicensed usage. In this paper, we will estimate spectrum that left for unlicensed usage and analyze risks for unlicensed users in unlicensed bands in terms of access opportunities and monetary gain. We will further provide recommendations that help foster unlicensed usage in unlicensed bands

The rich demystified: A reply to Bach, Corneo, and Steiner (2008)

The contribution Bach, Corneo and Steiner (2008) has argued that "the rich" do not pay taxes adequately in relation to their income, finding, for instance, an effective tax rate of only 38.1% for the 0.001% fractile of German income taxpayers in 2001. This result contrasts sharply with the legislated top marginal income tax rate of 48.5%. We subject the results contained in Bach, Corneo and Steiner (2008) to a rigorous analysis: We find major flaws and inconsistencies with regard to methodology, i.e. the omission of corporate taxes and inter-temporal aspects of taxation. Restating basic rules for the measurement of effective tax rates, we provide values for what we term the "comprehensive nominal tax rate" (CNTR) and show that the headline result in Bach, Corneo and Steiner (2008) of 38.1% is underestimated by over 12 percentage points. As an important distributional result, the CNTR increases with increasing taxable income. --Top Incomes,Income Taxation,Taxing the Rich,Comprehensive Tax Burden

Tradeable Spectrum Interference Rights

Spectrum rights have gained increasing attention since Ronald Coase pointed out that the most efficient way to assign spectrum is to give it to those users who value it most through property-like rights and secondary markets. Defining spectrum rights turns out to be difficult due to the nature of electronic emissions[1]. As a result, it may be more practical to define interference rights (similar to pollution rights) rather than exclusive usage rights. Interference rights give a user the right to interfere with another user up to a specified level. In this paper, we develop the idea of a market in spectrum interference rights and, using some plausible use cases, illustrate its characteristics. The paper therefore includes a detailed description of interference rights along with some first order quantitative modelling of the use cases coupled with qualitative analysis

Credibility-Based Binary Feedback Model for Grid Resource Planning

In commercial grids, Grid Service Providers (GSPs) can improve their profitability by maintaining the lowest possible amount of resources to meet client demand. Their goal is to maximize profits by optimizing resource planning. In order to achieve this goal, they require an estimate of the demand for their service, but collecting demand data is costly and difficult. In this paper we develop an approach to building a proxy for demand, which we call a value profile. To construct a value profile, we use binary feedback from a collection of heterogeneous clients. We show that this can be used as a proxy for a demand function that represents a client’s willingness-to-pay for grid resources. As with all binary feedback systems, clients may require incentives to provide feedback and deterrents to selfish behavior, such as misrepresenting their true preferences to obtain superior services at lower costs. We use credibility mechanisms to detect untruthful feedback and penalize insincere or biased clients. Finally, we use game theory to study how cooperation can emerge in this community of clients and GSPs

The Rich Demystified - A Reply to Bach, Corneo, and Steiner (2008)

The contribution Bach, Corneo, and Steiner (2008) has argued that “the rich” do not pay taxes adequately in relation to their income, finding, for instance, an effective tax rate of only 38.1% for the 0.001% fractile of German income taxpayers in 2001. This result contrasts sharply with the legislated top marginal income tax rate of 48.5%. We subject the results contained in Bach, Corneo, and Steiner (2008) to a rigorous analysis: We find major flaws and inconsistencies with regard to methodology, i.e. the omission of corporate taxes and inter-temporal aspects of taxation. Restating basic rules for the measurement of effective tax rates, we provide values for what we term the “comprehensive nominal tax rate” (CNTR) and show that the headline result in Bach, Corneo, and Steiner (2008) of 38.1% is underestimated by over 12 percentage points. As an important distributional result, the CNTR increases with increasing taxable income.top incomes, income taxation, taxing the rich, comprehensive nominal tax rate

Do Anti-Dumping Rules Facilitate the Abuse of Market Dominance?

We discuss the effects of AD-protection in a standard Dixit model of entry deterrence. In an AD-regime, the newcomer is constrained by a minimum-price rule in addition to existing irreversible entrance costs. For minimum prices which lie below the Stackelberg one, we find that AD- rules distort competition. We show that AD-protection increases the advantages of entry deterrence for a wide range of combinations of sunk costs and minimum prices. When entrance costs are hight, consumer welfare is lower in an AD-regime than under free trade. Consequently, AD-protection facilitates the abuse of market dominance.anti-dumping, abuse of market dominance, strategic firm behaviour

How Do Limitations in Spectrum Fungibility Impact Spectrum Trading?

Secondary markets for spectrum trading have been considered an important solution for generating spectrum opportunities in an environment where scarcity is the rule. Nonetheless, an important factor when envisioning a successful spectrum trading environment is to consider how comparable an available frequency is to the frequency an spectrum user prefers. With this aim, we consider the fungibility scores previously determined in [1] in order to explore further parameters that can influence this quantification of the level of fungibility. Further, we merge these fungibility calculations with an existing spectrum trading model, SPECTRAD [2], seeking to determine the actual impact of the limitations of spectrum fungibility in the market viability

Scalable XML Collaborative Editing with Undo short paper

Commutative Replicated Data-Type (CRDT) is a new class of algorithms that ensures scalable consistency of replicated data. It has been successfully applied to collaborative editing of texts without complex concurrency control. In this paper, we present a CRDT to edit XML data. Compared to existing approaches for XML collaborative editing, our approach is more scalable and handles all the XML editing aspects : elements, contents, attributes and undo. Indeed, undo is recognized as an important feature for collaborative editing that allows to overcome system complexity through error recovery or collaborative conflict resolution