Topology preservation is a crucial issue in parallel reductions that transform binary pictures by changing only a set of black points to white at a time. In this paper, we present sufficient conditions for topology-pr...
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Topology preservation is a crucial issue in parallel reductions that transform binary pictures by changing only a set of black points to white at a time. In this paper, we present sufficient conditions for topology-preserving parallel reductions on the three types of pictures of the unconventional 3D face-centered cubic (FCC) grid. Some conditions provide methods of verifying that a given parallel reduction always preserves the topology, and the remaining ones directly provide deletion rules of topology-preserving parallel reductions, and make us possible to generate topologically correct thinning algorithms. We give local characterizations of P-simple points, whose simultaneous deletion preserves the topology, and the relationships among the existing universal sufficient conditions for arbitrary types of binary pictures and our new FCC-specific results are also established.
Compared with far-developed measures and methods for mono-specific forest stands, the silvicultural prescriptions for mixed-species stands are at their early beginning. However, they are essential for the well-conceiv...
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Compared with far-developed measures and methods for mono-specific forest stands, the silvicultural prescriptions for mixed-species stands are at their early beginning. However, they are essential for the well-conceived establishment, design, and control of mixed-species stands, currently promoted in many countries worldwide. Here, we review the state of the art and we further develop silvicultural prescriptions for mixed-species stands for steering of experiments, stand modeling, and silviculture. We review which aspects of tree species mixing are most relevant for management goal achievement. We found the maintenance of species diversity and structural heterogeneity for ecological purpose, stabilizing productivity, and social-economic performance as main objectives. We give an overview of quantitatively formulated silvicultural prescriptions for steering mixed-species stands for forest practice, long-term experiments, forest stand models. Compared with the sophisticated guidelines for mono-specific stands, prescriptions for mixed stand are often mainly qualitative and vague. Then, we introduce methodological approaches in development for steering mixture: measures for spatial and temporal separation, species-specific growing space requirements for crop trees, coefficients for equivalence and density modification, and basic relationships for steering tree number and area-based mixing proportions. Finally, we draw conclusions for further development of methodological approaches for silvicultural steering of experiments, implementation in stand simulators, and for silvicultural operations. We see the need for improving the quantitative spatially explicit rules based at tree or cohort level, for substantiating the knowledge on species-specific allometry, growing area, tree-to-tree distances, and position-dependent competition indices for steering tree removal. We discuss the prospects and limitations of establishing silvicultural prescriptions for mixed-species stands
One of the severe problems in a fingerprint-based system is retaining the fingerprint images. In this paper, we propose a method to minimize the fingerprint images size and retain the reference points. The method is d...
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One of the severe problems in a fingerprint-based system is retaining the fingerprint images. In this paper, we propose a method to minimize the fingerprint images size and retain the reference points. The method is divided into three parts, the first part is about digital image preprocessing that allows us to eliminate the noise, improve the image, convert it into a binary image, detect the skeleton and locate the reference point. The second part concerns the detection of critical points by the Douglas-Peucker method. The final part presents the methodology for the fingerprint curves reconstruction using the fractal interpolation curves. The experimental result shows the accuracy of this reconstruction method. The relative error (ER) is between 2.007% and 5.627% and the mean squared error (MSE) is between 0.126 and 0.009 at a small iterations number. On the other hand, for a greater number of iterations, the ER is between 0.415% and 1.64% and MSE is between 0.000124 and 0.0167. This clearly indicates that the interpolated curves and the original curves are virtually identical and exceedingly close.
thinning is a widely used technique to obtain skeleton-like shape features (i.e., centerlines and medial surfaces) from digital binary objects. Conventional thinning algorithms preserve endpoints to provide important ...
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ISBN:
(纸本)9783642331404
thinning is a widely used technique to obtain skeleton-like shape features (i.e., centerlines and medial surfaces) from digital binary objects. Conventional thinning algorithms preserve endpoints to provide important geometric information relative to the object to be represented. An alternative strategy is also proposed that preserves isthmuses (i.e., generalization of curve/surface interior points). In this paper we present ten 3D parallel isthmus-based thinning algorithm variants that are derived from some sufficient conditions for topology preserving reductions.
The concept of a simple point is well known in digital topology: a black point in a binary picture is called a simple point if its deletion preserves topology. This paper introduces the notion of a simplifier point: a...
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ISBN:
(纸本)9783319591087;9783319591070
The concept of a simple point is well known in digital topology: a black point in a binary picture is called a simple point if its deletion preserves topology. This paper introduces the notion of a simplifier point: a black point in a binary picture is simplifier if it is simple, and its deletion turns a non-simple border point into simple. We show that simplifier points are line end points for both (8, 4) and (4, 8) pictures on the square grid. Our result makes efficient implementation of endpoint-based topology-preserving 2D thinning algorithms possible.
thinning is a frequently applied technique for extracting skeleton-like shape features (i.e., centerline, medial surface, and topological kernel) from volumetric binary images. Subfield-based thinning algorithms parti...
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ISBN:
(纸本)9783642137716
thinning is a frequently applied technique for extracting skeleton-like shape features (i.e., centerline, medial surface, and topological kernel) from volumetric binary images. Subfield-based thinning algorithms partition the image into some subsets which are alternatively activated, and some points in the active subfield are deleted. This paper presents a set of new 3D parallel subfield-based thinning algorithms that use four and eight subfields. The three major contributions of this paper are: 1) The deletion rules of the presented algorithms are derived from some sufficient conditions for topology preservation. 2) A novel thinning scheme is proposed that uses iteration-level endpoint checking. 3) Various characterizations of endpoints yield different algorithms.
To improve the spatial resolution of solid-state nanopores, thinning the membrane is a very important issue. The most commonly used membrane material for solid-state nanopores is silicon nitride (Si3N4). However, unti...
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To improve the spatial resolution of solid-state nanopores, thinning the membrane is a very important issue. The most commonly used membrane material for solid-state nanopores is silicon nitride (Si3N4). However, until now, stable wafer-scale fabrication of Si3N4 membranes with a thickness of less than 5 nm has not been reported, although a further reduction in thickness is desired to improve spatial resolution. In the present study, to fabricate thinner Si3N4 membranes with a thickness of less than 5 nm in a wafer, a new fabrication process that employs a polycrystalline-Si (poly-Si) sacrificial layer was developed. This process enables the stable fabrication of Si3N4 membranes with thicknesses of 3 nm. Nanopores were fabricated in the membrane using a transmission electron microscope (TEM) beam. Based on the relationship between the ionic current through the nanopores and their diameter, the effective thickness of the nanopores was estimated to range from 0.6 to 2.2 nm. Moreover, DNA translocation through the nanopores was observed.
Hilditch thinning algorithm is widely used in image pre-processing process. In this paper, we propose an improved Hilditch algorithm to acquire a more stable output. We conclude that the skeletons obtained from our al...
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ISBN:
(纸本)9780769539072
Hilditch thinning algorithm is widely used in image pre-processing process. In this paper, we propose an improved Hilditch algorithm to acquire a more stable output. We conclude that the skeletons obtained from our algorithms give better results in Chinese characters and numbers. The advantage of this algorithm corrects the beard by modifying the warp in the part of intersection.
A reduction transforms a binary picture only by changing some black points to white ones, which is referred to as deletion. Sequential reductions traverse the black points of a picture, and consider a single point for...
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A reduction transforms a binary picture only by changing some black points to white ones, which is referred to as deletion. Sequential reductions traverse the black points of a picture, and consider a single point for possible deletion, while parallel reductions can delete a set of black points simultaneously. Two reductions are called equivalent if they produce the same result for each input picture. A deletion rule is said to be equivalent if it yields a pair of equivalent parallel and sequential reductions. This paper introduces a class of equivalent deletion rules that allows us to establish a new sufficient condition for topology-preserving parallel reductions in arbitrary binary pictures. In addition we present a method of verifying that a deletion rule given by matching templates is equivalent, a necessary and sufficient condition for order-independent deletion rules, and a sufficient criterion for order-independent and translation-invariant parallel subfield-based algorithms.
We combine a process-based growth model for even-aged Norway spruce (Picea abies (L.) Karst.) with economics and optimization. Carbon storage is subsidized based on stand growth and product decay. We include detailed ...
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We combine a process-based growth model for even-aged Norway spruce (Picea abies (L.) Karst.) with economics and optimization. Carbon storage is subsidized based on stand growth and product decay. We include detailed optimized thinnings and timber quality features and present cost functions for stand-level CO2 storage. In contrast to earlier studies, our results suggest that changing thinning strategies and postponing thinnings are at least as important as lengthening the rotation period when considering economically efficient carbon storage. The role of thinning is most important in less fertile sites. Contrary to the generic Faustmann model, a higher interest rate increases rotation length on our fertile site. Including carbon release from decaying timber products as reductions from carbon subsidies only has minor effects on optimal solutions. The fertile site stores more discounted carbon. However, with a 1% interest rate, the less fertile site is cost-efficient up to 13 CO2 ***(-1), and with a 3% interest rate, it is cost-efficient up to 14 CO2 ***(-1). After these points, carbon storage on the fertile site becomes cheaper. The economic costs of carbon storage suggest that it is optimal to apply carbon storage in Norway spruce forests to meet greenhouse gas reduction commitments.
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