Detecting alternative graph clusterings

2012 ◽  
Vol 86 (1) ◽  
Author(s):  
Supreet Mandala ◽  
Soundar Kumara ◽  
Tao Yao
Keyword(s):  
Alternative Graph

scholarly journals The Region of Collision

1956 ◽  
Vol 9 (4) ◽  
pp. 448-453
Author(s):  
W. T. Slater
Keyword(s):  
Alternative Graph ◽  
Family Of Curves ◽  
Time Distance

Captain Wylie's paper on ‘The Region of Collision’ raises some interesting points but if one accepts the view that graphing of some sort is not wholly ‘academic’ the writer feels that there is an alternative graph which Captain Wylie has not mentioned and is worth considering.As Captain Wylie has shown, the time-distance plot gives very little useful information except that it does keep prominently in mind the distance between the two vessels. The time-bearing plot is much more informative as to the element of danger present in the situation but if the time-bearing is the only plot kept then the fact that it shows no distance between the vessels is a serious disadvantage. The writer suggests that it might be worthwhile considering the advantages of plotting change of bearing against distance between the vessels, especially if this is done on a graph having precomputed curves for various minimum separations between the vessels. The sort of graph obtained is illustrated in Fig. 1 which shows a family of curves for vessels maintaining steady courses and passing at minimum separations of ½, 1 and 1½ miles, curves A, B and C respectively, on the assumption that plotting is begun from the point where the vessels are four miles apart.

Understanding Conic Sections Using Alternate Graph Paper

2006 ◽  
Vol 99 (5) ◽  
pp. 322-327
Author(s):  
Elizabeth M. Brown ◽  
Elizabeth Jones
Keyword(s):  
Conic Sections ◽  
Coordinate Systems ◽  
Graph Paper ◽  
Alternative Graph

A description of two alternative coordinate systems and their use in graphing conic sections. This alternative graph paper helps students explore the idea of eccentricity using the definitions of the conic sections. Includes multiple examples of the uses of these alternative graphing sections, along with focus - directrix definitions of conic sections to be used with the new coordinate systems.

scholarly journals Graph-Based Image Matching for Indoor Localization

2019 ◽  
Vol 1 (3) ◽  
pp. 785-804 ◽  
Author(s):  
Mario Manzo
Keyword(s):  
Data Structures ◽  
Image Matching ◽  
Indoor Localization ◽  
Graph Matching ◽  
Image Representation ◽  
Spatial Relations ◽  
Content Based Image Retrieval ◽  
Adjacency Graph ◽  
Alternative Graph ◽  
Attributed Graph

Graphs are a very useful framework for representing information. In general, these data structures are used in different application domains where data of interest are described in terms of local and spatial relations. In this context, the aim is to propose an alternative graph-based image representation. An image is encoded by a Region Adjacency Graph (RAG), based on Multicolored Neighborhood (MCN) clustering. This representation is integrated into a Content-Based Image Retrieval (CBIR) system, designed for the vision-based positioning task. The image matching phase, in the CBIR system, is managed with an approach of attributed graph matching, named the extended-VF algorithm. Evaluated in a context of indoor localization, the proposed system reports remarkable performance.

USEFULNESS OF DIRECTED ACYCLIC SUBWORD GRAPHS IN PROBLEMS RELATED TO STANDARD STURMIAN WORDS

2009 ◽  
Vol 20 (06) ◽  
pp. 1005-1023 ◽  
Author(s):  
PAWEŁ BATURO ◽  
MARCIN PIATKOWSKI ◽  
WOJCIECH RYTTER
Keyword(s):  
Linear Time ◽  
Regular Structure ◽  
Special Structure ◽  
Graph Properties ◽  
Alternative Graph ◽  
Simple Alternative ◽  
Sturmian Words ◽  
Special Factors ◽  
Exponential Size ◽  
Standard Word

The class of finite Sturmian words consists of words having particularly simple compressed representation, which is a generalization of the Fibonacci recurrence for Fibonacci words. The subword graphs of these words (especially their compacted versions) have a very special regular structure. In this paper we investigate this structure in more detail than in previous papers and show how several syntactical properties of Sturmian words follow from their graph properties. Consequently simple alternative graph-based proofs of several known facts are presented. The very special structure of subword graphs leads also to special easy algorithms computing some parameters of Sturmian words: the number of subwords, the critical factorization point, lexicographically maximal suffixes, occurrences of subwords of a fixed length, and right special factors. These algorithms work in linear time with respect to n, the size of the compressed representation of the standard word, though the words themselves can be of exponential size with respect to n. Some of the computed parameters can be also of exponential size, however we provide their linear size compressed representations. We introduce also a new concept related to standard words: Ostrowski automata.

scholarly journals Structure Optimization of Mixed-Speed Train Traffic for Cyclic Timetable: Model and Algorithm Development

2022 ◽  
Vol 2022 ◽  
pp. 1-13
Author(s):  
Jiamin Zhang ◽  
Jiarui Zhang
Keyword(s):  
Job Shop ◽  
Structure Optimization ◽  
Rail Network ◽  
Buffer Time ◽  
Alternative Graph ◽  
Train Operation ◽  
Traffic Scenario ◽  
Dependent Setup Times ◽  
One Machine

Trains can be optimally spread over the period of the cyclic timetable. By integrating sequencing issue with headway time together, this paper studies the structure optimization of mixed-speed train traffic for a cyclic timetable. Firstly, by taking it as a job-shop problem with sequence-dependent setup times on one machine, in the type of infinite capacity resource with headway (ICR + H), the problem is transformed to alternative graph (AG) and then recast to the mixed-speed train traffic planning (MSTTP) model. For the multiobjective in MSTTP, three indicators are optimized, i.e., heterogeneity, cycle time, and buffer time, which correspond to diversity of train service toward passenger, capacity consumption of rail network, and stability of train operation, respectively. Secondly, the random-key genetic algorithm (RKGA) is proposed to tackle the sequence and headway simultaneously. Finally, RKGA is coded with visual studio C# and the proposed method is validated with a case study. The rail system considered is a line section encompassing a territory of 180 km with 15 mixed-speed trains in each cycle of the timetable. Results indicate the comprehensively balanced train plan for all stakeholders from random variations of train sequence and headway time. Both the quantitative proportion of heterogeneity/homogeneity (e.g., 2.5) about the optimized distribution of the mixed train traffic and the link between train headway time and the sequence for each traffic scenario are found. All the findings can be used to arrange the mixed-speed train traffic more scientifically.

scholarly journals Time-Dependent Alternative Route Planning: Theory and Practice

Algorithms ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 220
Author(s):  
Spyros Kontogiannis ◽  
Andreas Paraskevopoulos ◽  
Christos Zaroliagis
Keyword(s):  
Travel Time ◽  
Real World ◽  
Route Planning ◽  
Theory And Practice ◽  
Time Dependent ◽  
Planning Theory ◽  
Alternative Route ◽  
Alternative Graph ◽  
Query Algorithm ◽  
Alternative Routes

We consider the problem of computing a set of meaningful alternative origin-to-destination routes, in real-world road network instances whose arcs are accompanied by travel-time functions rather than fixed costs. In this time-dependent alternative route scenario, we present a novel query algorithm, called Time-Dependent Alternative Graph (TDAG), that exploits the outcome of a time-consuming preprocessing phase to create a manageable amount of travel-time metadata, in order to provide answers for arbitrary alternative-routes queries, in only a few milliseconds for continental-size instances. The resulting set of alternative routes is aggregated in the form of a time-dependent alternative graph, which is characterized by the minimum route overlap, small stretch factor, small size, and low complexity. To our knowledge, this is the first work that deals with the time-dependent setting in the framework of alternative routes. The preprocessed metadata prescribe the minimum travel-time informations between a small set of “landmark” nodes and all other nodes in the graph. The TDAG query algorithm carries out the work in two distinct phases: initially, a collection phase constructs candidate alternative routes; consequently, a pruning phase cautiously discards uninteresting or low-quality routes from the candidate set. Our experimental evaluation on real-world, time-dependent road networks demonstrates that TDAG performed much better (by one or two orders of magnitude) than the existing baseline approaches.

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