Parenting while serving as a frontline leader is uniquely stressful, yet little is known about how family responsibilities shape physiological stress in these roles. We followed emergency physicians and tactical police leaders, comparing parents of young children with non-parents across four days: one critical mission day, two standard workdays, and one non-workday. Using wearable sensing, expert activity labeling, and daily debriefs, we inferred stress only in sedentary epochs via a normalized-heart-rate method, with an HRV-based index as benchmark. Parents showed higher stress on workdays and non-workdays, but not on critical mission days, where attentional narrowing and strict device policies appear to suppress parenting-related differences. We contribute: (i) in-the-wild physiological evidence that parenthood amplifies stress mainly under permeable boundaries, (ii) a pragmatic stress-labeling pipeline for safety-critical settings, (iii) a configuration-based account linking boundaries, attention, and parenting, and (iv) design implications for stress-aware boundary management systems, supported by an open analysis repository.

Digital libraries have focused on change to images from the perspectives of prevention and reversal. Since change is a required component of scholarship, we seek to adding the modeling of change to support its characterization. In this paper we discuss change to images in traditional media and propose a formal model of that change. The subject calls for a kaleidoscopic approach as tracking changes in images is an interesting exercise in storytelling, both when one looks at deliberately changing them with a purpose and at tracking past changes.

In this article, we introduce a framework for the geometric design and fabrication of a family of geometrically interlocking space-filling shapes, which we call woven tiles. Our framework is based on a unique combination of (1) Voronoi partitioning of space using curve segments as the Voronoi sites and (2) the design of these curve segments based on weave patterns closed under symmetry operations. The underlying weave geometry provides an interlocking property to the tiles and the closure property under symmetry operations ensure single tile can fill space. In order to demonstrate this general framework, we focus on specific symmetry operations induced by fabric weaving patterns. We specifically showcase the design and fabrication of woven tiles on flat and curved domains by using the most common 2-fold fabrics, namely, plain, twill, and satin weaves. We further evaluate and compare the mechanical behavior of the so created woven tiles through finite element analysis.

Operating machinery while distracted is a dangerous behavior, often habitual, which is the source of accidents. Distracted driving in particular has assumed the form of an epidemic, fueled by the ubiquity of smartphone usage and the tendency to slip into absent-mindedness in tedious commutes. Here we show that a method capable of detecting and communicating overarousal trends associated with the onset of distractions, can pull the driver out of a downward psychophysiological spiral. The method is reliable, unobtrusive, and subtle in its intervention-all important characteristics for real-time corrections on human handling of critical machinery. Arousal estimation is performed by a conservative statistical filter acting upon the driver's perinasal perspiration signal, as this is continuously extracted from a thermal imaging feed. Overarousal notices are communicated via a visual indicator placed in the driver's peripheral vision. Using this method, we conducted a parallel group experiment, where a control CLCL (n=23n=23) and a biofeedback BFBF (n=24n=24) cohort were distracted mentally and physically while driving, with only the biofeedback group receiving the benefit of overarousal notification. Results show that heeding biofeedback notices, cuts dramatically the time BFBF subjects are engaged in distractions with respect to the control group, significantly reducing their arousal levels and improving their driving behaviors in the context of a typical commute.

In this paper, we introduce a geometric design and fabrication framework for a family of interlocking space-filling shapes which we call bi-axial woven tiles. Our framework is based on a unique combination of (1) Voronoi partitioning of space using curve segments as the Voronoi sites and (2) the design of these curve segments based on weave patterns closed under symmetry operations. The underlying weave geometry provides an interlocking property to the tiles and the closure property under symmetry operations ensure single tile can fill space. In order to demonstrate this general framework, we focus on specific symmetry operations induced by bi-axial weaving patterns. We specifically showcase the design and fabrication of woven tiles by using the most common 2-fold fabrics called 2-way genus-1 fabrics, namely, plain, twill, and satin weaves.

Recent advances in the computer graphics of woven images in 3-space motivate the development of a model for weavings on arbitrary surfaces of higher genus. Our paradigm differs markedly from what Grünbaum and Shepard have provided for the plane. In particular, we induce our weavings from graph imbeddings on surfaces in 3-space. Additionally, we show that the two most frequently invoked subdivision algorithms in computer graphics, the Catmull--Clark and Doo--Sabin algorithms, correspond nicely to topological surgery operations on the induced weavings. The inherently topological formulation of our model permits a graphic designer to superimpose strand colors and geometric attributes---distances, angles, and curvatures---that conform to manufacturing or artistic criteria.

This paper introduces paper-strip sculptures, a physical mesh data-structure used to represent 2-manifold mesh surfaces for understanding topological and geometrical aspects of shape modeling with visual and tactual examples. With paper strips it is possible to construct simple paper sculptures that can convincingly illustrate a variety of ideas in shape modeling - such as 2-manifold mesh surfaces, discrete Gaussian curvature, and the Gauss-Bonnet theorem - with hands-on experiments. Such sculptures can also represent links, knots and weaving. Paper-strip sculptures are also useful to represent and understand non-orientable surfaces such as the projective plane and the Klein bottle.

It has recently been shown that if we twist an arbitrary subset of edges of a mesh on an orientable surface, the resulting extended graph rotation system (EGRS) can be used to induce a cyclic weaving on the surface. In extended graph rotation systems, an edge is viewed as a paper strip that can be twisted. The sides of the paper strips provide ``two strands'' to construct weaving structures. Either these strands are ``parallel'' to the mesh edge for an ``untwisted edge'', or they both cross over the edge and over each other for a ``twisted edge''. If an arbitrary subset of edges of a mesh on an orientable surface is twisted in the same helical sense, then the EGRS induces a cyclic plain-weaving on the surface, which consists of cycles that cross other cycles (or themselves) by alternatingly going over and under. In this paper, we show that it is always possible to create a single-cycle plain-weaving starting from a mesh on an arbitrary surface, by selecting an appropriate subset of edges to be twisted. We also demonstrate how, starting from a mesh, to construct a large number of single-cycle plain-woven objects. Interestingly, the single-cycle solutions with a minimal number of edge twists correspond to plain-woven objects that are visually similar to Celtic knots. For converting plain-weaving cycles to 3D thread structures, we extend the original projection method, which previously worked only when all mesh edges are twisted. With the extension described here, our projection method can also be used to handle untwisted edges. We have developed a system that converts any manifold mesh into single-cycle plain-woven objects, by interactively controlling the proportion of edges that are twisted. The system also allows us to change the shapes of the threads with a set of parameters, interactively in real-time. We demonstrate here that by using this system, we can create a wide variety of single-cycle plain-woven objects.

In this paper, we show how to create plain-weaving over an arbitrary surface. To create a plain-weaving on a surface, we need to create cycles that cross other cycles (or themselves) by alternatingly going over and under. We use the fact that it is possible to create such cycles, starting from any given manifold-mesh surface by simply twisting every edge of the manifold mesh. We have developed a new method that converts plain-weaving cycles to 3D thread structures. Using this method, it is possible to cover a surface without large gaps between threads by controlling the sizes of the gaps. We have developed a system that converts any manifold mesh to a plain-woven object, by interactively controlling the shapes of the threads with a set of parameters. We have demonstrated that by using this system, we can create a wide variety of plain-weaving patterns, some of which may not have been seen before.

Both hair rendering and global illumination are known to be computationally expensive, and for this reason we see very few examples using global illumination techniques in hair rendering. In this paper, we elaborate on different simplification approaches to allow practical global illumination solutions for high quality hair rendering. We categorize light paths of a full global illumination solution, and analyze their costs and illumination contributions both theoretically and experimentally. We also propose two different implementation techniques using our novel projection based indirect illumination computation approach and state of the art ray tracing for hair. Our results show that by using our simplifications, a global illumination solution for hair is practical.

This paper presents our recent theoretical results on high genus modeling. We introduce a new concept called regular handles. Using regular handles it is possible to increase genus without increasing the number of vertices. Using regular handles a wide variety of mesh structures can be constructed. One of the usages of regular handles is to construct families of regular meshes, which is useful to create a wide variety of high genus mesh structures.

This paper presents our preliminary results on regular meshes in which all faces have the same size and all vertices have the same valence. A regular mesh is denoted by (n, m, g) where n is the number of the sides of faces, m is the valence of vertices and g is the genus of the mesh. For g = 0, regular meshes include regular platonic solids, all two sided polygons. For g = 1 regular meshes include regular tilings of infinite plane. Our work shows that there exist infinitely many regular meshes for g > 1. Moreover, we have constructive proofs that describe how to create high genus regular meshes that consist of triangles and quadrilaterals (3, m, g) and (4, m, g).

Most frequently used subdivision schemes such as Catmull-Clark create regular regions after several applications. This paper shows that all semi-regular regions can be created by subdivision schemes and each semi-regular region type can be created with one application of a particular subdivision scheme to a particular regular region. Using this property of subdivision schemes it is easy to cover any given surface with semi-regular tiles by applying one semi-regularity creating subdivision after several applications of a regularity creating subdivision.

In this paper, we present a set of generalized "local" mesh operators. Local operators are those that operate on a single face without affecting the rest of the mesh. Boundary edges of the chosen face also stay the same. We have identified two types of local operators: (1) Extrusions that create generalized pipes in which bottom and top polygons have the same number of sides, and (2) Stellations that create generalized pyramids, where there is a top vertex instead of top polygon. Our operators can create extrusions that are regular polyhedra including dodecahedron, icosa-hedron, octahedron and tetrahedron. The tetrahedron is created using the stellation operator, which is also useful to create generalized versions of Kepler and Poinsot solids.

Triangular and quadrilateral meshes are commonly used in computer graphics applications. We analyze the topological existence of meshes that consist of n-sided faces where n is greater than 4 such as pentagonal and hexagonal meshes. We show that it is possible to represent any 2-manifold with a mesh that is made up of only pentagons. We also show that the meshes that consist of only polygons with more than five sides cannot represent all 2-manifolds. We present a pentagonalization (or pentagonal conversion) scheme that can create a pentagonal mesh from any arbitrary mesh structure. We also introduce a pentagonal preservation scheme that can create a pentagonal mesh from any pentagonal mesh.

No abstract available.

In this paper, we describe a technique, with roots in topological graph theory, that we call rind modeling. It provides for the easy creation of surfaces resembling peeled and punctured rinds. We show how the method's two main steps of: 1) creation of a shell or crust like the rind of an orange, and 2) opening holes in the crust by punching or peeling can be encapsulated into a real time semi-automatic interactive algorithm. We include a number of worked examples, some by students in a first modeling course, that demonstrate the ease with which a large variety of intricate rind shapes can be created.

We present two methods to create realistic Chinese painting. The first method is to create 3D Chinese painting animation using existing software packages. The second method is an expressive paint tool which allows an artist to interactively create 2D Chinese painting.

In this work, we present a method to interactively create multi-segment, curved handles between two star-shaped faces of an orientable 2-manifold mesh or to connect two 2-manifold meshes along such faces. The presented algorithm combines a very simple 2D morphing algorithm with Hermite interpolation to construct the handle. Based on the method, we have developed a user interface tool that allows users to simply and easily create multi-segment curved handles.

We present a prototype system for robust, interactive and user friendly modeling of orientable 2-manifold meshes. To develop the system we introduce new topological entities for effectively manipulating 2-manifold mesh structures. We identify a minimal set of fundamental operators, which is necessary and sufficient for performing all homeomorphic and topological operations on 2-manifold mesh structures. Extremely efficient algorithms are developed for the implementation of these operators. We also developed a set of powerful, user-friendly, and effective operators at the level of user interface. Users of our system can perform a large set of homeomorphic and topological changes with these user interface level operators. Our system is topologically robust in the sense that users will never create invalid 2-manifold mesh structure with these operators. In our system, the homeomorphic and topological surgery operations can be applied alternatively on 2-manifold meshes. With our system, users can blend surfaces, construct crusts and open holes on these crusts. With our system, the shapes that look like solid, non-manifold, or 2-manifold with boundary can be manipulated. The system also provides automatic texture mapping during topology changes.

The Doubly Linked Face List (DLFL) structure introduces a powerful modeling paradigm that allows users to alternatively apply topological change operations and subdivision operations on a mesh structure. Moreover the DLFL is topologically robust in the sense that it always guarantees valid 2-manifold surfaces. We further study the relationship between DLFL structure and subdivision algorithms. First, we develop a new corner cutting scheme, which provides a tension parameter to control the shape of the subdivided surface. Second, we develop a careful and efficient algorithm for our corner cutting scheme on the DLFL structure that uses only the basic operations provided by the DLFL structure. This implementation ensures that our new corner cutting scheme preserves topological robustness. The comparative study shows that the corner cutting schemes create better handles and holes than Catmull-Clark (1978) scheme.

Modeling three-dimensional faces on the computer has been an interesting yet challenging problem. This paper presents a method for creating cartoon faces by using a subdivision scheme. We use set-operations for conceptual design of subdivision control meshes. To ensure the quality of the control mesh, we have eliminated high valenced extraordinary vertices since smoothness of the surface decreases with valence. In addition, we have limited the number of extraordinary vertices to eliminate ripples. We have also ensured an even structure around extraordinary vertices (The size of each quadrilateral in subdivided meshes are roughly similar). We have also developed a user-friendly interface to sculpt the control mesh. Using this interface we have been able to create a variety of cartoon faces.

Abstract This paper summarizes a function‐based approach to model and animate 2D and 3D flows. We use periodic functions to create cyclical animations that represent 2D and 3D flows. These periodic functions are constructed with an extremely simple algorithm from a set of oriented lines. The speed and orientation of the flow are described directly by the orientation and the lengths of these oriented lines. The resulting cyclical animations are then obtained by sampling the constructed periodic functions. Our approach is independent of dimension, i.e. for 2D and 3D flow the same types of periodic functions are used. Rendering images for 2D and 3D flows is slightly different. In 2D function values directly are mapped to color values. On the other hand, in 3D function values are first mapped to color and opacity and then the volume is rendered by our volume renderer. Modeled and animated flows are used to improve the visualization of operations of rolling piston and rotary vane compressors. Copyright © 2001 John Wiley & Sons, Ltd.

We present a simple and intuitive rendering technique to create abstract paintings. This technique allows the users to render a given animated scene with multiple cameras, using a method inspired by concepts used by cubist and futurist abstract painters. In our method, the number of cameras is unlimited and the camera parameters are continuous functions. We define the camera parameters as parametric functions that are described by images, which we call camera-control-images. The spatial distribution color in these camera-control-images determines the camera parameters such as position and orientation. For the creation of abstract paintings, we have developed two artistic techniques. In the first technique, artists incrementally paint a complicated camera-control-image for a given 3D scene. The second technique is the opposite of the first. In this technique, for a given camera-control-image artists incrementally built a 3D scene to create an interesting abstract painting. The second technique is helpful when using existing images such as photographs and paintings.

The authors present a paradigm that allows dynamic changing of the topology of 2-manifold polygonal meshes. Our paradigm always guarantees topological consistency of polygonal meshes. Based on our paradigm, by simply adding and deleting edges, handles can be created and deleted, holes can be opened or closed, polygonal meshes can be connected or disconnected. These edge insertion and edge deletion operations are highly consistent with subdivision algorithms. In particular, these operations can be easily included into a subdivision modeling system such that the topological changes and subdivision operations can be performed alternatively during model construction. We demonstrate practical examples of topology changes based on this new paradigm and show that the new paradigm is convenient, effective, efficient, and friendly to subdivision surfaces.

Meshes are the most commonly used objects in computer graphics. They generalize polyhedra by using non-planar faces. Modeling 2D manifold meshes with a simple user interface is an important problem in computer-aided geometric design. In this paper, we propose a conceptual framework for mesh modeling systems that guarantees topologically correct 2D manifolds. Our solution is based on graph rotation systems developed in topological graph theory. As an internal representation of meshes, we use a doubly-linked face list (DLFL). We have also developed a visual representation of the topology that provides a powerful tool for developing a user interface to manipulate the topology of the mesh.

We obtain a generalized version of the well-known distance function family L/sub p/ norm. We prove that the new functions satisfy distance function properties. By using these functions, convex symmetric shapes can be described as loci, the set of points which are in equal distance from a given point. We also show that these symmetric convex shapes can be easily parameterized. We also show these distance functions satisfy a Lipschitz-type condition. We provide a fast ray marching algorithm for rendering shapes described by these distance functions. These distance functions can be used as building blocks for some implicit modeling tools such as soft objects, constructive soft geometry, function representations (freps) or ray quadrics.