804 research outputs found
The B36/S125 "2x2" Life-Like Cellular Automaton
The B36/S125 (or "2x2") cellular automaton is one that takes place on a 2D
square lattice much like Conway's Game of Life. Although it exhibits high-level
behaviour that is similar to Life, such as chaotic but eventually stable
evolution and the existence of a natural diagonal glider, the individual
objects that the rule contains generally look very different from their Life
counterparts. In this article, a history of notable discoveries in the 2x2 rule
is provided, and the fundamental patterns of the automaton are described. Some
theoretical results are derived along the way, including a proof that the speed
limits for diagonal and orthogonal spaceships in this rule are c/3 and c/2,
respectively. A Margolus block cellular automaton that 2x2 emulates is
investigated, and in particular a family of oscillators made up entirely of 2 x
2 blocks are analyzed and used to show that there exist oscillators with period
2^m(2^k - 1) for any integers m,k \geq 1.Comment: 18 pages, 19 figure
An Exact Algorithm for TSP in Degree-3 Graphs via Circuit Procedure and Amortization on Connectivity Structure
The paper presents an O^*(1.2312^n)-time and polynomial-space algorithm for
the traveling salesman problem in an n-vertex graph with maximum degree 3. This
improves the previous time bounds of O^*(1.251^n) by Iwama and Nakashima and
O^*(1.260^n) by Eppstein. Our algorithm is a simple branch-and-search
algorithm. The only branch rule is designed on a cut-circuit structure of a
graph induced by unprocessed edges. To improve a time bound by a simple
analysis on measure and conquer, we introduce an amortization scheme over the
cut-circuit structure by defining the measure of an instance to be the sum of
not only weights of vertices but also weights of connected components of the
induced graph.Comment: 24 pages and 4 figure
Superpatterns and Universal Point Sets
An old open problem in graph drawing asks for the size of a universal point
set, a set of points that can be used as vertices for straight-line drawings of
all n-vertex planar graphs. We connect this problem to the theory of
permutation patterns, where another open problem concerns the size of
superpatterns, permutations that contain all patterns of a given size. We
generalize superpatterns to classes of permutations determined by forbidden
patterns, and we construct superpatterns of size n^2/4 + Theta(n) for the
213-avoiding permutations, half the size of known superpatterns for
unconstrained permutations. We use our superpatterns to construct universal
point sets of size n^2/4 - Theta(n), smaller than the previous bound by a 9/16
factor. We prove that every proper subclass of the 213-avoiding permutations
has superpatterns of size O(n log^O(1) n), which we use to prove that the
planar graphs of bounded pathwidth have near-linear universal point sets.Comment: GD 2013 special issue of JGA
Vertex-Unfoldings of Simplicial Polyhedra
We present two algorithms for unfolding the surface of any polyhedron, all of
whose faces are triangles, to a nonoverlapping, connected planar layout. The
surface is cut only along polyhedron edges. The layout is connected, but it may
have a disconnected interior: the triangles are connected at vertices, but not
necessarily joined along edges.Comment: 10 pages; 7 figures; 8 reference
All Maximal Independent Sets and Dynamic Dominance for Sparse Graphs
We describe algorithms, based on Avis and Fukuda's reverse search paradigm,
for listing all maximal independent sets in a sparse graph in polynomial time
and delay per output. For bounded degree graphs, our algorithms take constant
time per set generated; for minor-closed graph families, the time is O(n) per
set, and for more general sparse graph families we achieve subquadratic time
per set. We also describe new data structures for maintaining a dynamic vertex
set S in a sparse or minor-closed graph family, and querying the number of
vertices not dominated by S; for minor-closed graph families the time per
update is constant, while it is sublinear for any sparse graph family. We can
also maintain a dynamic vertex set in an arbitrary m-edge graph and test the
independence of the maintained set in time O(sqrt m) per update. We use the
domination data structures as part of our enumeration algorithms.Comment: 10 page
Proximity Drawings of High-Degree Trees
A drawing of a given (abstract) tree that is a minimum spanning tree of the
vertex set is considered aesthetically pleasing. However, such a drawing can
only exist if the tree has maximum degree at most 6. What can be said for trees
of higher degree? We approach this question by supposing that a partition or
covering of the tree by subtrees of bounded degree is given. Then we show that
if the partition or covering satisfies some natural properties, then there is a
drawing of the entire tree such that each of the given subtrees is drawn as a
minimum spanning tree of its vertex set
PENGARUH PENAMBAHAN LENSA NOZZLE DAN JUMLAH BLADE AIRFOIL TIPE NACA 4415 TERHADAP HASIL DAYA LISTRIK TURBIN ANGIN SUMBU HORISONTAL
Danur Lambang Pristiandaru. PENGARUH PENAMBAHAN LENSA NOZZLE
TURBIN ANGIN DAN JUMLAH BLADE AIRFOIL TIPE NACA 4415
TERHADAP HASIL DAYA LISTRIK. Skripsi, Fakultas Keguruan dan Ilmu
Pendidikan Universitas Sebelas Maret Surakarta. Januari 2016
Tujuan penelitian ini adalah: (1) Menyelidiki pengaruh jumlah blade pada
turbin angin non-twisted blade tipe airfoil NACA 4415 terhadap daya listrik yang
dihasilkan. (2) Menyelidiki pengaruh penambahan lensa nozzle pada turbin angin
non-twisted blade tipe airfoil NACA 4415 terhadap daya listrik yang dihasilkan
turbin angin. (3) Menyelidiki pengaruh bersama (interaksi) antara penambahan
lensa nozzle dan jumlah blade terhadap daya listrik yang dihasilkan turbin angin.
Penelitian ini menggunakan metode deskriptif kuantitatif. Sampel dalam
penelitian ini adalah Turbin Angin Sumbu Horisontal (TASH) dengan desain blade
airfoil NACA 4415 non-twisted. 3 desain lensa nozzle digunakan untuk mengetahui
pengaruhnya terhadap peningkatan daya listrik TASH. Terdapat 3 variasi jumlah
blade yaitu jumlah blade 2, jumlah blade 3, dan jumlah blade 4. Variasi kecepatan
angin yang digunakan dalam penelitian ini adalah 2,5 m/s, 3,5 m/s, dan 4,5 m/s.
Data diperoleh dengan melakukan pengujian TASH menggunakan angin rekayasa,
daya listrik yang dihasilkan dibaca dan direkam oleh data logger. Data yang
diperoleh dari hasil penelitian dimasukkan ke dalam tabel dan ditampilkan dalam
bentuk grafik, kemudian dianalisis.
Berdasarkan hasil penelitian dapat disimpulkan bahwa: (1) Adanya
pengaruh variasi jumlah blade terhadap daya listrik turbin angin. TASH 3 blade
menghasilkan daya listrik yang paling besar yaitu 0,7222 W pada kecepatan angin
4,5 m/s. (2) Adanya pengaruh penambahan lensa nozzle terhadap turbin angin.
Lensa nozzle mampu meningkatkan hasil daya listrik turbin angin semua jenis
variasi jumlah blade dibandingkan turbin angin tanpa lensa nozzle. (3) Ada
pengaruh bersama yang signifikan antara variasi jumlah blade dan variasi jenis
lensa terhadap daya listrik turbin angin. TASH 3 blade dengan lensa C pada
kecepatan angin 4,5 m/s memiliki daya listrik tertinggi yaitu sebesar 0,82041 W.
Daya listrik tersebut meningkat 13,60% dibanding TASH 3 blade tanpa
penambahan lensa, yaitu 0,7222 W.
Kata kunci: Turbin Angin, Lensa Nozzle, Daya Listrik, Data Logge
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