Land-use Change and Forestry in Austria: A Scientific Assessment of Austria's Carbon Balance in Light of Article 3 of the Kyoto Protocol

Article 3 of the Kyoto Protocol states that Parties included in Annex I shall use net changes in greenhouse gas emissions from sources and removals by sinks resulting from direct human-induced land-use change and forestry (LUCF) activities since 1990 to meet their their emission reduction commitments. However, even with clear guidelines on how to calculate LUCF emissions and removals, considerable problems remain. Our paper addresses a number of relevant issues by summarizing the knowledge gained from assessing and quantifying sources and sinks of carbon compounds relevant to Austria on the basis of an interated operational model framework, the "Austrian Carbon Balance Model" (ACBM). The ACBM covers Austria's biosphere and technosphere and at present permits project researchers to run a Reference Scenario for 1990-2050. We attempt to generalize our experience and also to compare our model results regarding Austria's net atmospheric carbon contribution on the basis of uncertainties underlying these results. This permits us (1) to identify several high-priority research issues that will enable Austria to cope adequately with its commitments under the Kyoto Protocol; and (2) to draw general conclusions that may provide support to the Conference of the Parties as it decides upon modalities, rules and guidelines in accounting for LUCF emissions and removals

Backdoor DNFs

We introduce backdoor DNFs, as a tool to measure the theoretical hardness of CNF formulas. Like backdoor sets and backdoor trees, backdoor DNFs are defined relative to a tractable class of CNF formulas. Each conjunctive term of a backdoor DNF defines a partial assignment that moves the input CNF formula into the base class. Backdoor DNFs are more expressive and potentially smaller than their predecessors backdoor sets and backdoor trees. We establish the fixed-parameter tractability of the backdoor DNF detection problem. Our results hold for the fundamental base classes Horn and 2CNF, and their combination. We complement our theoretical findings by an empirical study. Our experiments show that backdoor DNFs provide a significant improvement over their predecessors