10,146 research outputs found
Logic Programming Applications: What Are the Abstractions and Implementations?
This article presents an overview of applications of logic programming,
classifying them based on the abstractions and implementations of logic
languages that support the applications. The three key abstractions are join,
recursion, and constraint. Their essential implementations are for-loops, fixed
points, and backtracking, respectively. The corresponding kinds of applications
are database queries, inductive analysis, and combinatorial search,
respectively. We also discuss language extensions and programming paradigms,
summarize example application problems by application areas, and touch on
example systems that support variants of the abstractions with different
implementations
Bylaw Governance
This article argues that Delaware corporate law permits shareholders to use bylaws to circumscribe the managerial authority of the board of directors. While shareholders cannot mandate action by the board, they can enact specific prohibitions on its behavior, so long as the board retains enough discretion to implement—in practice, not merely in theory—its managerial policies by other means. The use of such circumscribing bylaws to discourage shirking (or analogous managerial abuses) by the directors or officers resembles the use of negative covenants in debt contracts that seek to prevent the debtor from squandering assets. Bylaw governance thus subtly but significantly reallocates governance power within the corporation, so as to reduce the agency costs of management. Its legal validity should also prompt courts and scholars alike to focus less on the quantity of power wielded by the shareholders, and more on the ways that power can be configured to produce managerial efficiencies
Polynomial tuning of multiparametric combinatorial samplers
Boltzmann samplers and the recursive method are prominent algorithmic
frameworks for the approximate-size and exact-size random generation of large
combinatorial structures, such as maps, tilings, RNA sequences or various
tree-like structures. In their multiparametric variants, these samplers allow
to control the profile of expected values corresponding to multiple
combinatorial parameters. One can control, for instance, the number of leaves,
profile of node degrees in trees or the number of certain subpatterns in
strings. However, such a flexible control requires an additional non-trivial
tuning procedure. In this paper, we propose an efficient polynomial-time, with
respect to the number of tuned parameters, tuning algorithm based on convex
optimisation techniques. Finally, we illustrate the efficiency of our approach
using several applications of rational, algebraic and P\'olya structures
including polyomino tilings with prescribed tile frequencies, planar trees with
a given specific node degree distribution, and weighted partitions.Comment: Extended abstract, accepted to ANALCO2018. 20 pages, 6 figures,
colours. Implementation and examples are available at [1]
https://github.com/maciej-bendkowski/boltzmann-brain [2]
https://github.com/maciej-bendkowski/multiparametric-combinatorial-sampler
Robustness and edge addition strategy of air transport networks : a case study of 'the Belt and Road'
Air transportation is of great importance in "the Belt and Road" (the B&R) region. The achievement of the B&R initiative relies on the availability, reliability, and safety of air transport infrastructure. A fundamental step is to find the critical elements in network performance. Considering the uneven distributions of population and economy, the current literature focusing on centrality measures in unweighted networks is not sufficient in the B&R region. By differentiating power and centrality in the B&R region, our analysis leads to two conclusions: (1) Deactivating powerful nodes causes a larger decrease in efficiency than deactivating central nodes. This indicates that powerful nodes in the B&R region are more critical than central nodes for network robustness. (2) Strategically adding edges between high powerful and low powerful nodes can enhance the network's ability to exchange resources efficiently. These findings can be used to adjust government policies for air transport configuration to achieve the best network performance and the most cost effective
Health Relevant Behavior and its Impact on the Physician-Patient Relationship
The importance of the physician-patient relationship for the health care market is beyond controversy. Recent work emphasizes a two-sided asymmetric information relationship between physician and patient. In contrast to most work looking only at the physician's perspective, our paper concentrates on the patient's view. Estimation results support the hypotheses that physician consultation and health relevant behavior are not stochastically independent. In the recursive bivariate probit model, patient’s health relevant behavior has a significant influence on the probability of a physician visit. This means that health care demand and not only the contact decision is determined by both, patient and physician.physician-patient relationship, health behavior, bivariate probit panel
Function extraction
AbstractLow-level imperative programming languages typically have complex operational semantics (e.g. derived from an underlying processor architecture). In this paper, we describe an automatic method for extracting recursive functions from such low-level programs. The functions are derived by formal deduction from the semantics of the programming language. For each function extracted, a proof of correspondence to the original program is automatically constructed. Subsequent program verification can then be done without referring to the details of the low-level programming language semantics at all: it suffices to prove properties of the extracted function. The technique is explained for simple while programs and also for the machine code of a widely used processor. We show how heuristics can enhance the output from the function extractor/decompiler and how the technique aids implementation of a trustworthy compiler. Our tools have been implemented in the HOL4 theorem prover
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