EXTENDED SKIP GRAPHS FOR EFFICIENT KEY SEARCH IN PEER-TO-PEER ENVIRONMENT

2007 ◽  
Vol 08 (02) ◽  
pp. 119-132
Author(s):  
SATOSHI FUJITA ◽  
AKIRA OHTSUBO ◽  
MASAYA MITO
Keyword(s):  
Performance Improvement ◽  
Ordered Set ◽  
Distributed Data ◽  
Graceful Degradation ◽  
Cost Performance ◽  
Routing Performance ◽  
Significant Performance ◽  
Totally Ordered Set ◽  
Skip Graphs ◽  
The Cost

In this paper, we propose three techniques to improve the cost/performance of the skip graph that was recently proposed by Aspnes and Shah. The skip graph, which is a distributed data structure that could efficiently support find, insert, and delete operations of a key drawn from a totally ordered set, consists of N nodes each of which is connected with exactly log 2 N nodes determined by a set of random binary vectors called membership vectors. In the following, we will extend the construction of the skip graph in the following two directions: 1) proposal of a subgraph of the skip graph which realizes a graceful degradation of the routing performance when the number of neighbors reduces from log 2 N, and 2) proposal of a supergraph of the skip graph which realizes a significant performance improvement when the number of neighbors increases from log 2 N. The performance of those extended graphs will be evaluated analytically.

scholarly journals Roughing Milling with Ceramic Tools in Comparison with Sintered Carbide on Nickel-Based Alloys

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 734
Author(s):  
Pablo Fernández-Lucio ◽  
Octavio Pereira Neto ◽  
Gaizka Gómez-Escudero ◽  
Francisco Javier Amigo Fuertes ◽  
Asier Fernández Valdivielso ◽  
...  
Keyword(s):  
Cutting Speed ◽  
High Volume ◽  
Cemented Carbide ◽  
Performance Ratio ◽  
Cost Performance ◽  
Ceramic Tools ◽  
The Cost ◽  
Engine Components ◽  
Coated Carbide ◽  
Milling Tools

Productivity in the manufacture of aircrafts components, especially engine components, must increase along with more sustainable conditions. Regarding machining, a solution is proposed to increase the cutting speed, but engines are made with very difficult-to-cut alloys. In this work, a comparison between two cutting tool materials, namely (a) cemented carbide and (b) SiAlON ceramics, for milling rough operations in Inconel® 718 in aged condition was carried out. Furthermore, both the influence of coatings in cemented carbide milling tools and the cutting speed in the ceramic tools were analysed. All tools were tested until the end of their useful life. The cost performance ratio was used to compare the productivity of the tested tools. Despite the results showing higher durability of the coated carbide tool, the ceramic tools presented a better behavior in terms of productivity at higher speed. Therefore, ceramic tools should be used for higher productivity demands, while coated carbide tools for low speed-high volume material removal.

A weak derivative approach to optimization of threshold parameters in a multicomponent maintenance system

2001 ◽  
Vol 38 (02) ◽  
pp. 386-406 ◽  
Author(s):  
Bernd Heidergott
Keyword(s):  
Optimization Problems ◽  
Estimation Algorithm ◽  
Replacement Policy ◽  
Cost Performance ◽  
Weak Derivative ◽  
Preventive Replacement ◽  
Maintenance System ◽  
Threshold Optimization ◽  
Age Replacement ◽  
The Cost

We consider a multicomponent maintenance system controlled by an age replacement policy: when one of the components fails, it is immediately replaced; all components older than a threshold age θ are preventively replaced. Costs are associated with each maintenance action, such as replacement after failure or preventive replacement. We derive a weak derivative estimator for the derivative of the cost performance with respect to θ. The technique is quite general and can be applied to many other threshold optimization problems in maintenance. The estimator is easy to implement and considerably increases the efficiency of a Robbins-Monro type of stochastic approximation algorithm. The paper is self-contained in the sense that it includes a proof of the correctness of the weak derivative estimation algorithm.

ON RIBBON PRESENTATIONS OF RIBBON KNOTS

1994 ◽  
Vol 03 (02) ◽  
pp. 223-231
Author(s):  
TOMOYUKI YASUDA
Keyword(s):  
Partially Ordered Set ◽  
Ordered Set ◽  
Partially Ordered ◽  
Totally Ordered Set

A ribbon n-knot Kn is constructed by attaching m bands to m + 1n-spheres in the Euclidean (n + 2)-space. There are many way of attaching them; as a result, Kn has many presentations which are called ribbon presentations. In this note, we will induce a notion to classify ribbon presentations for ribbon n-knots of m-fusions (m ≥ 1, n ≥ 2), and show that such classes form a totally ordered set in the case of m = 2 and a partially ordered set in the case of m ≥ 1.

scholarly journals On the structure of the totally ordered set of unimodal cycles

2001 ◽  
Vol 25 (5) ◽  
pp. 323-329 ◽  
Author(s):  
Irene Mulvey
Keyword(s):  
Ordered Set ◽  
Totally Ordered Set

We continue the study of a class of unimodal cycles where each cycle in the class is forced by every unimodal cycle not in the class. For every order, we identify the cycle in the class of that order, which is maximal with respect to the forcing relation.

scholarly journals The increased use value of bamboo leaves as silica source for t-type zeolite synthesis

2018 ◽  
Vol 197 ◽  
pp. 05003 ◽  
Author(s):  
Soni Setiadji ◽  
Citra Deliana Dewi Sundari ◽  
Endang Lala ◽  
Denia Febby Nurbaeti ◽  
Ira Novianti ◽  
...  
Keyword(s):  
Sem Analysis ◽  
High Price ◽  
Heating Process ◽  
Zeolite Synthesis ◽  
X Ray Diffraction ◽  
Cost Performance ◽  
Silica Source ◽  
Bamboo Leaves ◽  
Type Zeolite ◽  
The Cost

T-type zeolite can be used as catalyst, adsorbent, and membranes for gas separation. The synthesis of T-type zeolite needs to be optimized in both of the method and source of precursor, because of its relatively high price. In this research, the synthesis is done using silica extracted from bamboo leaves instead of commercial silica. This increases the value of the bamboo leaves and the cost-performance of zeolite synthesis. The silica was extracted from bamboo leaves ash using alkaline solvent. The extracted silica has 81.76% of purity and an amorphous phase. The T-type zeolite was synthesized using the molar composition of 0.15 Na2O : 0.025 Al : 0.15 K2O : 1 SiO2 : 15 H2O : 0.06 TMAOH, under hydrothermal method and heating process for 4 days, 60°C for 2 days and 120°C for the next 2 days. The characterization method using X-Ray Diffraction and Infra-Red Spectroscopy were performed to confirm the formation of T-type zeolite. The results of Scanning Electron Microscope (SEM) analysis show that the formed T-type zeolite has erionite cylindrical crystal shape.

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