A discriminative view of MRF pre-processing algorithms

While Markov Random Fields (MRFs) are widely used in computer vision, they present a quite challenging inference problem. MRF inference can be accelerated by pre-processing techniques like Dead End Elimination (DEE) or QPBO-based approaches which compute the optimal labeling of a subset of variables. These techniques are guaranteed to never wrongly label a variable but they often leave a large number of variables unlabeled. We address this shortcoming by interpreting pre-processing as a classification problem, which allows us to trade off false positives (i.e., giving a variable an incorrect label) versus false negatives (i.e., failing to label a variable). We describe an efficient discriminative rule that finds optimal solutions for a subset of variables. Our technique provides both per-instance and worst-case guarantees concerning the quality of the solution. Empirical studies were conducted over several benchmark datasets. We obtain a speedup factor of 2 to 12 over expansion moves without preprocessing, and on difficult non-submodular energy functions produce slightly lower energy.Comment: ICCV 201

Living on the Edge: Assessing the Effects of Catastrophic Fire on Plants Utilized by Two Endemic Subspecies of Spring Mountains Butterflies

In the past few decades there has been an increase in catastrophic, high-intensity, large-scale wildfires globally due to the combination of climate warming with more than a century of fire suppression policy. One region that has been drastically affected is the Western United States, as there has been an increase in ‘mega-fires’ in the past few decades. The 2013 Carpenter 1 Fire in the Spring Mountains, Nevada was the largest fire in recorded history in these mountains, spreading out over 11,137 hectares. Catastrophic fire like the Carpenter 1 Fire can have potentially devastating effects on endemic species inhabiting refugia on ‘sky-islands.’ The understory response to this catastrophic fire was measured using 52-1m2 plots in a burn area that supports two endemic butterfly subspecies, the Mount Charleston blue butterfly and Morand’s checkerspot, to test for resistance and resilience of sky-island species to catastrophic fire. Plots were placed in unburned, low severity burn, and high severity burn areas. The species richness of the understory was measured in the varying degrees of burn severity, while the specific nectar and larval host plant abundances of the two butterflies were measured to determine if the fire increased habitat by opening up high pre-fire tree density areas. Three years post-fire I found total species richness of understory vegetation to be greatest in unburned areas, only one species less in low severity burn areas, and significantly less in high severity burn areas. The plant community that existed pre-fire was found to have a legacy effect, as areas of high pre-fire tree density, resulting in high severity burns, were biased towards shade-tolerant plants. In contrast, areas of low pre-fire tree density, resulting in low severity burns, were biased towards plants that occur in more open, sunny conditions. The nectar plants of both butterfly species, Erigeron clokeyi and Hymenoxys lemmonii, recovered past plant densities capable of supporting the butterflies in the low severity burn. However, only Hymenoxys lemmonii has recovered enough to support the butterflies in high severity burn areas. Two of the three larval host plants of the Mount Charleston blue butterfly, Astragalus calycosus and Oxytropis oreophila have surpassed unburned densities in the low severity burn. However, only Astragalus calycosus has recovered in sufficient plant densities to support the butterfly in the high severity burn. Neither larval host plant for the Morand’s checkerspot, Castilleja martinii and Penstemon leiophyllus have recovered in either burn severity in sufficient plant densities to support the butterfly. The larval host plants of the Morand’s checkerspot may be later successional species, as Castilleja martinii occurs in old burn areas. Grasses have not surpassed unburned densities, which is important for the butterflies as high densities of grasses can impede flight behavior. Non-native species were absent throughout the study in all burn severities. These results provide insight into the resistence and resiliency of sky-island refugia to catastrophic fire

The Application of Farm Programs to Commercial Fisheries: The Case of Crop Insurance for the Bristol Bay Commercial Salmon Fisheries

Under the direction of the Agricultural Risk Protection Act of 2000, the U.S. Congress proposed a crop insurance program for the Bristol Bay, Alaska, commercial salmon fishery. This study examines the feasibility of extending crop insurance to this commercial fishery. The specific focus of this analysis is on differences between this commercial capture fishery and agricultural enterprises in the context of property rights and producer control. Findings show that differences between this commercial fishery and agricultural enterprises would require substantial modifications to existing crop insurance programs. Furthermore, it is recommended that the consideration of extending crop insurance be delayed until this fishery is rationalized.Bristol Bay, commercial fisheries, crop insurance, farm programs, property rights, risk management, salmon, Agricultural and Food Policy, Risk and Uncertainty,

Devotion in an Age of Distraction

Dr. Arand explores our connection to creation in our devotional life

Living In the Promises and Place of God- A Theology of The World

This Concordia Pages explores how locating the story of salvation within the broader, biblical story of creation impacts our witness in the world. In particular, it considers how being placed alongside our fellow creatures as recipients of God’s goodness and mercy opens up the possibility for a reciprocity of witness—the way in which our lives, contingent and intertwined, allow for both Christians and non-Christians to bear witness to the work and wonder of God. In such a context, the uniqueness of the Christian witness finds renewed purchase and possibility

Attending to the Beauty of Creation and the New Creation

The beauty of the earth, in all its intricacies, is a gift of the creator to us. And its value is not practical or ethical, but is given to us simply to delight us even as God delights in it. And it is powerful. N. T. Wright notes that beauty, whether in God’s creation or in human art, “is sometimes so powerful that it evokes our very deepest feelings of awe, wonder, gratitude, and reverence.”1 Beauty blossoms into appreciation for God’s creation and love of the creator

Living in the Promises and Places of God A Theology of the World

In this discourse mutual witness is possible as the lives of both Christians and non-Christians function as a testimony to part of the story of God

PARTICIPATION DECISIONS, ANGLER WELFARE, AND THE REGIONAL ECONOMIC IMPACT OF SPORTFISHING

We link a stochastic binary choice model of individual decisions to participate in the marine sport fisheries in Cook Inlet, Alaska, with a simulation- based sample enumeration procedure for aggregating estimates of individual angler welfare and a regionally adjusted zip code-level input-output model of regional economic activity. The result is a behaviorally based model for predicting changes in angler welfare and regional economic activity occasioned by changes in the demand for sportfishing that arise from changes in trip costs or the expected number, size, or mix of species caught. The advantages of this approach are that: changes in angler participation are determined by variables that are observable, predictable, or subject to management control; participation reflects declining marginal utility, and substitution and complementary effects across trip attributes; estimates of changes in aggregate angler welfare and changes in regional economic impacts are derived from changes in individual participation probabilities.Resource /Energy Economics and Policy,