Logic Programming for Finding Models in the Logics of Knowledge and its Applications: A Case Study

The logics of knowledge are modal logics that have been shown to be effective in representing and reasoning about knowledge in multi-agent domains. Relatively few computational frameworks for dealing with computation of models and useful transformations in logics of knowledge (e.g., to support multi-agent planning with knowledge actions and degrees of visibility) have been proposed. This paper explores the use of logic programming (LP) to encode interesting forms of logics of knowledge and compute Kripke models. The LP modeling is expanded with useful operators on Kripke structures, to support multi-agent planning in the presence of both world-altering and knowledge actions. This results in the first ever implementation of a planner for this type of complex multi-agent domains.Comment: 16 pages, 1 figure, International Conference on Logic Programming 201

On the Road to Sustainability? A Review of a Half-Century of Biodiversity Conservation Successes in Nepal and Some Thoughts on Future Needs

We review the history, over the past half-century, of biodiversity conservation legislation and programs in Nepal. We especially consider how they have evolved in light of some earlier concerns resulting from, for example, the strict “fines and fences” conservation approaches first implemented in the 1970s, to pressing issues that emerged over time such as park-people and wildlife-human conflicts, poaching and illegal wildlife trade. We also consider how the implementation of international conservation agreements and demographic and political changes have affected conservation programs in Nepal. We finish by discussing conservation in the context of sustainable development and conclude with some thoughts on future research and managerial needs in a rapidly-changing world

Modeling Stable Matching Problems with Answer Set Programming

The Stable Marriage Problem (SMP) is a well-known matching problem first introduced and solved by Gale and Shapley (1962). Several variants and extensions to this problem have since been investigated to cover a wider set of applications. Each time a new variant is considered, however, a new algorithm needs to be developed and implemented. As an alternative, in this paper we propose an encoding of the SMP using Answer Set Programming (ASP). Our encoding can easily be extended and adapted to the needs of specific applications. As an illustration we show how stable matchings can be found when individuals may designate unacceptable partners and ties between preferences are allowed. Subsequently, we show how our ASP based encoding naturally allows us to select specific stable matchings which are optimal according to a given criterion. Each time, we can rely on generic and efficient off-the-shelf answer set solvers to find (optimal) stable matchings.Comment: 26 page

Deconstructing Local Adaptation Plans for Action (LAPAs) - Analysis of Nepal and Pakistan LAPA initiatives

This paper analyses the organizational and implementation design strategies of two ongoing Local Adaptation Plan for Action (LAPA) initiatives in Nepal and Pakistan. LAPA is considered an answer for institutionalized local-level adaptation planning that aims to capture local needs and direct resources to where, when and by whom these are most needed. While both Nepal and Pakistan LAPAs have similar objectives of bottom-up planning, the operational and structural designs of the two LAPAs are very distinct, leading to different outcomes. Different internal and external factors such as age and size of LAPA, technology, local institutional arrangements, core process and environment also exert significant structural tensions on the planned organizational design of LAPAs that may inhibit delivery of their objectives

Interval-type and affine arithmetic-type techniques for handling uncertainty in expert systems

AbstractExpert knowledge consists of statements Sj (facts and rules). The facts and rules are often only true with some probability. For example, if we are interested in oil, we should look at seismic data. If in 90% of the cases, the seismic data were indeed helpful in locating oil, then we can say that if we are interested in oil, then with probability 90% it is helpful to look at the seismic data. In more formal terms, we can say that the implication “if oil then seismic” holds with probability 90%. Another example: a bank A trusts a client B, so if we trust the bank A, we should trust B too; if statistically this trust was justified in 99% of the cases, we can conclude that the corresponding implication holds with probability 99%.If a query Q is deducible from facts and rules, what is the resulting probability p(Q) in Q? We can describe the truth of Q as a propositional formula F in terms of Sj, i.e., as a combination of statements Sj linked by operators like &, ∨, and ¬; computing p(Q) exactly is NP-hard, so heuristics are needed.Traditionally, expert systems use technique similar to straightforward interval computations: we parse F and replace each computation step with corresponding probability operation. Problem: at each step, we ignore the dependence between the intermediate results Fj; hence intervals are too wide. Example: the estimate for P(A∨¬A) is not 1. Solution: similar to affine arithmetic, besides P(Fj), we also compute P(Fj&Fi) (or P(Fj1&⋯&Fjd)), and on each step, use all combinations of l such probabilities to get new estimates. Results: e.g., P(A∨¬A) is estimated as 1

Community-based DOTS and family member DOTS for TB control in Nepal: costs and cost-effectiveness

<p>Abstract</p> <p>Background</p> <p>Two TB control strategies appropriate for South Asia (a community-based DOTS [CBD] strategy and a family-based DOTS [FBD] strategy) have been shown to be effective in Nepal in meeting the global target for the proportion of registered patients successfully treated. Here we estimate the costs and cost-effectiveness of the two strategies. This information is essential to allow meaningful comparisons between these and other strategies and will contribute to the small but growing body of knowledge on the costs and cost-effectiveness of different approaches to TB control.</p> <p>Methods</p> <p>In 2001–2, costs relating to TB diagnosis and care were collected for each strategy. Structured and semi-structured questionnaires were used to collect costs from health facility records and a sample of 10 patients in each of 10 districts, 3 using CBD and 2 using FBD. The data collected included costs to the health care system and social costs (including opportunity costs) incurred by patients and their supervisors. The cost-effectiveness of each strategy was estimated.</p> <p>Results</p> <p>Total recurrent costs per patient using the CBD and FBD strategies were US$76.2 and US$84.1 respectively. The social costs incurred by patients and their supervisors represent more than a third of total recurrent costs under each strategy (37% and 35% respectively). The CBD strategy was more cost-effective than the FBD strategy: recurrent costs per successful treatment were US$91.8 and US$102.2 respectively.</p> <p>Discussion</p> <p>Although the CBD strategy was more cost-effective than the FBD strategy in the study context, the estimates of cost-effectiveness were sensitive to relatively small changes in underlying costs and treatment outcomes. Even using these relatively patient-friendly approaches to DOTS, social costs can represent a significant financial burden for TB patients.</p

The Conducting Ring Viewed as a Wormhole

We compute the exterior Green function for a grounded equi-potential circular ring in two-dimensional electrostatics by treating the system geometrically as a "squashed wormhole" with an image charge located in a novel but obvious position, thereby implementing a method first suggested in 1897 by Sommerfeld. We compare and contrast the strength and location of the image charge in the wormhole picture with that of the conventional point of view where an image charge is located inside the circular ring. While the two viewpoints give mathematically equivalent Green functions, we believe they provide strikingly different physics perspectives. We also comment on earlier Green function results by Hobson in 1900, and by Davis and Reitz in 1971, who applied Sommerfeld's method to analyze a grounded conducting circular disk in three-dimensional electrostatics.Comment: 13 figure

Measurement of the creep behavior of thin ZrNi metallic glass films – a comparison between nanoindentation relaxation, nanoindentation creep and lab-on-chips experiments

The characterization of the time-dependent behavior of thin metallic glass films is one of the key-issue for surface engineering. Such a measurement requires loading a constant material volume located in the thin film. Unfortunately, this condition is not fulfilled in the commonly used creep nanoindentation testing, contrary to micro tensile lab-on-chip experiments or micropillar compression testing. In this paper, we show that nanoindentation relaxation is an efficient alternative to nanoindentation creep. For that purpose, an extensive study of ZrNi metallic glasses viscoplastic behavior is performed using several experimental set-up (lab on chips, nanoindentation relaxation, nanoindentation creep, constant strain rate, ...). An innovative nanoindentation methodology is used to perform long-term relaxation tests up to 10 h with excellent reproducibility. It consists in maintaining a constant contact area during the test by controlling the contact stiffness between the tip and the material. Nanoindentation relaxation, constant strain rate loading and lab-on-chips data lead to similar values of apparent activation volume and strain rate sensitivity, whereas nanoindentation creep clearly overestimates the activation volume (Fig 1). Finite element modelling of nanoindentation creep and nanoindentation relaxation also confirms this trend. We evidence, thanks to the long-term indentation relaxation test that the underlying deformation mechanisms remain unchanged on the entire investigated strain rate range. Please click Additional Files below to see the full abstract