Three-dimensional packings with rotations
نویسندگان
چکیده
We present approximation algorithms for the three-dimensional strip packing problem, and the three-dimensional bin packing problem. We consider orthogonal packings where ninety-degree rotations are allowed. The algorithms we show for these problems have asymptotic performance bounds 2.64, and 4.89, respectively. These algorithms are for the more general case in which the bounded dimensions of the bin given in the input are not necessarily equal (that is, we consider bins for which the length, the width and the height are not necessarily equal). Moreover, we show that these problems —in the general version— are as hard to approximate as the corresponding oriented version.
منابع مشابه
Investigation of pore-scale random porous media using lattice boltzmann method
The permeability and tortuosity of pore-scale two and three-dimensional random porous media were calculated using the Lattice Boltzmann method (LBM). Effects of geometrical parameters of medium on permeability and tortuosity were investigated as well. Two major models of random porous media were reconstructed by computerized tomography method: Randomly distributed rectangular obstacles in a uni...
متن کاملKinematic Mapping and Forward Kinematic Problem of a 5-DOF (3T2R) Parallel Mechanism with Identical Limb Structures
The main objective of this paper is to study the Euclidean displacement of a 5-DOF parallel mechanism performing three translation and two independent rotations with identical limb structures-recently revealed by performing the type synthesis-in a higher dimensional projective space, rather than relying on classical recipes, such as Cartesian coordinates and Euler angles. In this paper, Study's...
متن کاملApollonian Circle Packings of the Half-plane
We consider Apollonian circle packings of a half Euclidean plane. We give necessary and sufficient conditions for two such packings to be related by a Euclidean similarity (that is, by translations, reflections, rotations and dilations) and describe explicitly the group of self-similarities of a given packing. We observe that packings with a non-trivial self-similarity correspond to positive re...
متن کاملDensest local sphere-packing diversity. II. Application to three dimensions.
The densest local packings of N three-dimensional identical nonoverlapping spheres within a radius R(min)(N) of a fixed central sphere of the same size are obtained for selected values of N up to N=1054. In the predecessor to this paper [A. B. Hopkins, F. H. Stillinger, and S. Torquato, Phys. Rev. E 81, 041305 (2010)], we described our method for finding the putative densest packings of N spher...
متن کاملThree-Dimensional Rotations as Products of Simpler Rotations
Three-Dimensional Rotations as Products of Simpler Rotations 1. The most general 3 × 3 rotation matrix In a class handout entitled, Three-Dimensional Proper and Improper Rotation Matrices, I derived the following general form for a 3× 3 matrix representation of a proper rotation by an angle θ in a counterclockwise direction about a fixed rotation axis parallel to the unit vector n̂ = (n1, n2, n3...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Computers & OR
دوره 36 شماره
صفحات -
تاریخ انتشار 2009