Query complexity for searching multiple marked states from an unsorted database

An important and usual problem is to search all states we want from a database with a large number of states. In such, recall is vital. Grover's original quantum search algorithm has been generalized to the case of multiple solutions, but no one has calculated the query complexity in this case. We will use a generalized algorithm with higher precision to solve such a search problem that we should find all marked states and show that the practical query complexity increases with the number of marked states. In the end we will introduce an algorithm for the problem on a ``duality computer'' and show its advantage over other algorithms.Comment: 4 pages,4 figures,twocolum

Simulating the tail of the interference in a Poisson network model

Interference among simultaneous transmissions represents the main limitation factor for the capacity and connectivity of dense wireless networks. In this paper we provide efficient simulation laws for the tail of the interference in a simple wireless ad hoc network model. Particularly, we consider node locations distributed according to a Poisson point process and various classes of light-tailed fading distribution

Estimation of N2O emission factors for soils depending on environmental conditions and crop management

Nitrous oxide (N2O) contributes 8% to anthropogenic global warming, of which about one third are direct emissions of agricultural soils. These N2O emissions are often estimated using the default IPCC 2006 emission factor of 1% of the amount of N applied for mineral fertilizer, manure and crop residues. However, a large variation in emission factors exists due to differences in environment (e.g. weather and soil conditions), crops (grassland, arable land, crop residues) and management (e.g. type of manure and fertilizer, application rates, time of application). We developed a simple approach to determine N2O emission factors that depend on environmental, crop and management factors. The main factors controlling N2O emission are nitrate content, oxygen content, available C content, temperature and pH. The starting point of the method was a two-year monitoring study of Velthof et al. (1996), who found an emission factor of exactly 1% for grassland on a sandy soil fertilized with calcium ammonium nitrate. The conditions of this experiment were set as the reference from which the effects of other environmental conditions and management on the N2O emission factor were estimated. Based on literature and expert knowledge we determined for 19 sources of N input, three soil types, two land use types, three precipitation classes, two pH classes and three temperature classes the effect on the default emission factor. The calculated N2O emission factors ranged from 0 to 10%. The approach was applied to a European scale, using the INTEGRATOR model. The results were also produced with the standard IPCC approach and the empirical approach by Stehfest and Bouwman (2006). Differences in the overall results at EU27 scale and at regional scale are discussed. The emission factors derived from this inference scheme can improve predictions of N2O emissions with integrated large-scale model

Circular 116

Free-range reindeer in western Alaska are managed for both velvet antler and meat production. Optimal management should maximize the income generated from both meat and antler production while managing the herd at levels below the carrying capacity of the range. Meat production precludes future antler production from harvested animals, therefore harvest decisions should reflect antler and body growth rates, current antler and meat prices, natural survival rates, and population demographics. We present a user-friendly computer model to generate estimates of net income under different harvest levels and market conditions. Input variables include sex- and agespecific survival rates, harvest levels, castration rates, antler weights, body weights, and recapture rates, as well as reproductive rates, fixed and variable costs, antler price, and meat price. Mark—Recapture analysis was used to estimate survival rates. The model was calibrated using reindeer herd records from 1984-1997. Output includes changes in herd size and composition over a thirty-year period, meat production, antler production, female: male ratio, and predicted net income. The model illustrates the sensitivity of herd size to female adult survival rates

Comparison of indices for the prediction of nitrogen mineralization after destruction of managed grassland

Intensively managed grasslands are occasionally chemically killed with herbicide and ploughed in order to grow an arable crop. After this management, large N mineralization rates with large losses to the environment are commonly observed. However, it remains to be determined to what extent the chemical killing contribute to increased N mineralization. In this study the potential nitrogen (N) mineralization from grasslands, that were killed with herbicides but otherwise undisturbed, was investigated in a laboratory experiment with undisturbed soil columns. Subsequently we assessed the predictive value of several laboratory indices for N mineralization after chemically killing of the grass. Mineralization rates varied from 0.5 to 3.0 g N m-2 wk-1. The contents of total N, total C, dissolved organic carbon (DOC) and hot-KCl extractable NH4 + were best related to N mineralization rates (R2=50, 48, 38 and 47%, respectively). In combination with information on the N content of the roots and stubble and the age of grassland at destruction, up to 62% of the variation in N mineralization rates could be explained. Although previous studies suggested that dissolved organic nitrogen (DON) is a good indicator for mineralization rates, this was not the case after chemically killing grass in the current study

The collusive drawbacks of sequential auctions

Sequential first-price auctions for multiple objects are very common in procurement, electricity, tobacco, timber, and oil lease markets. In this paper we identify two ways in which a sequential format may facilitate collusion among bidders relative to a simultaneous one. The first effect relates to the cartel’s ability to identify and punish defectors within the sequence, thus lowering the gains from a deviation with respect to a simultaneous format. The second effect concerns the cartel’s ability to allocate the bidder with the highest incentive to deviate (the ‘maverick’) to the last object of the sequence, thus increasing the viability of the collusive agreement. We then analyze how the seller may counteract this two effects by limiting the amount of information disclosed to bidders across rounds, and find that partial disclosure policies have little impact on the sustainability of collusion

Higher Dimensional Transition Systems

We introduce the notion of higher dimensional transition systems as a model of concurrency providing an elementary, set-theoretic formalisation of the idea of higher dimensional transition. We show an embedding of the category of higher dimensional transition systems into that of higher dimensional automata which cuts down to an equivalence when we restrict to non-degenerate automata. Moreover, we prove that the natural notion of bisimulation for such structures is a generalisation of the strong history preserving bisimulation, and provide an abstract categorical account of it via open maps. Finally, we define a notion of unfolding for higher dimensional transition systems and characterise the structures so obtained as a generalisation of event structures

Evaluating an online learning community: Intellectual, social and emotional development and transformations.

Developing online learning communities is a promising pedagogical approach in online learning contexts for adult tertiary learners, but it is no easy task. Understanding how learning communities are formed and evaluating their efficacy in supporting teaching-learning involves a complex set of issues that have a bearing on the design and facilitation of successful online learning experiences. This paper presents findings of a case study of a semester-long online graduate course designed to facilitate a learning community at a New Zealand tertiary institution. It adopts a sociocultural analytical framework and argues for a multiple developmental analytical approach to evaluating learning that considers lecturer and student intellectual, social and emotional development and transformations. Implications are presented for online lecturers, course designers and institutional administrators

Editorial: Assessment and ICT, innovative practices and future possibilities

The New Zealand Curriculum [NZC] document states that information and communication technology [ICT] and eLearning have considerable potential to support the teaching approaches recommended in the curriculum (Ministry of Education, 2007). In this special issue, we explore the potential for ICTs to support innovative assessment practices that complement effective teaching approaches. Such innovations can enrich the opportunities students have to demonstrate their developing understandings and knowledge, and foster a sense of responsibility for their own and group/class learning. Designed thoughtfully, they can also promote positive student attitudes and motivation towards learning in curriculum learning areas, and towards learning in general

A framework for developing and implementing an online learning community

Developing online learning communities is a promising pedagogical approach in online learning contexts for adult tertiary learners, but it is no easy task. Understanding how learning communities are formed and evaluating their efficacy in supporting learning involves a complex set of issues that have a bearing on the design and facilitation of successful online learning experiences. This paper describes the development of a framework for understanding and developing an online learning community for adult tertiary learners in a New Zealand tertiary institution. In accord with sociocultural views of learning and practices, the framework depicts learning as a mediated, situated, distributed, goal-directed, and participatory activity within a socially and culturally determined learning community. Evidence for the value of the framework is grounded in the findings of a case study of a semester-long fully online asynchronous graduate course. The framework informs our understanding of appropriate conditions for the development and conduct of online learning communities. Implications are presented for the design and facilitation of learning in such contexts