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Parameter Analysis for Guarding Terrains

Akanksha Agrawal, Sudeshna Kolay, Meirav Zehavi, Susanne Albers
2020 Scandinavian Workshop on Algorithm Theory  
In this paper, we focus on the parameterized complexity of Terrain Guarding (both discrete and continuous) with respect to two natural parameters.  ...  We also show that, when parameterized by the number c of minima in the terrain, Discrete Orthogonal Terrain Guarding has an XP algorithm.  ...  Let (T, k) be an instance of Discrete Orthogonal Terrain S WAT 2 0 2 0 4:12 Parameter Analysis for Guarding Terrains Guarding.  ... 
doi:10.4230/lipics.swat.2020.4 dblp:conf/swat/AgrawalKZ20 fatcat:7ushypru55d7nfwfdkjz3kb4eq

Efficient parallel implementations of approximation algorithms for guarding 1.5D terrains

Goran Martinović, Domagoj Matijević, Domagoj Ševerdija
2015 Croatian Operational Research Review  
In the 1.5D terrain guarding problem, an x-monotone polygonal line is defined by k vertices and a G set of terrain points, i.e. guards, and a N set of terrain points which guards are to observe (guard)  ...  This paper will show that if the (1 + ϵ)-approximate solver for the corresponding linear program is a computer, for any ϵ > 0, an extra 1 + ϵ factor will appear in the final approximation factor for both  ...  The analysis strictly follows that of [3] which is given for ϵ = 0. The cost of rounded point-guards is w( X 0 ) ≤ 1 α ∑ g∈X0 w g x ′ g ≤ 1 α (1 + ϵ) ∑ p∈N y ′ p .  ... 
doi:10.17535/crorr.2015.0007 fatcat:teqrulo4lrdyji3xgun35hnd3m

An Approximation Scheme for Terrain Guarding [chapter]

Matt Gibson, Gaurav Kanade, Erik Krohn, Kasturi Varadarajan
2009 Lecture Notes in Computer Science  
We obtain a polynomial time approximation scheme for the terrain guarding problem improving upon several recent constant factor approximations.  ...  We thank the anonymous reviewers for useful feedback. References  ...  Guarding Terrains via Local Search Recall that our input is a polygonal terrain, a set X of points on the terrain that need to be guarded, a set G of possible guard locations, and a parameter 0 < ǫ < 1  ... 
doi:10.1007/978-3-642-03685-9_11 fatcat:n52ldvsfjnaf7ols7s5baigahm

Practical Approaches to Partially Guarding a Polyhedral Terrain [chapter]

Frank Kammer, Maarten Löffler, Paul Mutser, Frank Staals
2014 Lecture Notes in Computer Science  
We study the problem of placing guard towers on a terrain such that the terrain can be seen from at least one tower.  ...  In this paper, we consider the problem on polyhedral terrains, and we allow the guards to see only a fixed fraction of the terrain, rather than everything.  ...  This work has been partially supported by the Netherlands Organisation for Scientific Research (NWO) under grants 639.021.123 and 612.001.022.  ... 
doi:10.1007/978-3-319-11593-1_21 fatcat:e4p7gly5gncdvctjq5vfs536ry

Simulationof Wimax 802.16E Physical Layermodel

Olalekan Bello Olalekan Bello
2013 IOSR Journal of Electrical and Electronics Engineering  
In this thesis, the performance analysis is being done by studying the bit loss and Packet losses that occurred during transmission over channel.  ...  For this purpose a simulation model of WiMAX PHY layer transmitter and Receiver has been designed using MATLAB.  ...  ion Factor, n 144/125 Ratio of Guard t ime to useful symbol time, G 1/16 Table 3 : 3 Terrai n type for S UI channel Terrain Type SUI Channels C (Mostly flat terrain with light tree densities  ... 
doi:10.9790/1676-530812 fatcat:h34win5mrzbixllaf4333ddbpy

Inapproximability Results for Guarding Polygons and Terrains

S. Eidenbenz, C. Stamm, P. Widmayer
2001 Algorithmica  
We show that this inapproximability for the POINT GUARD problem for polygons with holes carries over to the problem of covering a 2.5-dimensional terrain with a minimum number of guards that are placed  ...  The same holds if the guards may be placed on the terrain itself.  ...  The authors thank the anonymous referees for helpful suggestions based on an earlier version of this paper.  ... 
doi:10.1007/s00453-001-0040-8 fatcat:usi2v5te5zfxhkjd7lignpqvvm

Development of Avalanche Information System using Remote Sensing and GIS Technology in the Indian Karakoram Himalaya

H. S. Gusain, H. S. Negi, Sudhir Dhamija, V. D. Mishra, , Snehmani
2019 Current Science  
Terrain parameters, e.g. slope, aspect, elevation, etc. have been derived using DEM. Sites in avalanche-prone areas have been identified using terrain parameters and snowfall information.  ...  Villages in the region, camp locations of borderguarding personnel, pedestrian routes followed by villagers and border-guarding personnel, avalanche sites along pedestrian routes, etc. have been digitized  ...  We thank the Director, SASE, Chandigarh for constant encouragement, and the scientists/technical officers/ staff of SASE for collection and compilation of snow avalanche and climatology data of Karakoram  ... 
doi:10.18520/cs/v117/i1/104-109 fatcat:62dline4gzcxbhfkyxwfhg3v3e

Finding minimum hidden guard sets in polygons—tight approximability results

Stephan Eidenbenz
2006 Computational geometry  
Eidenbenz, Optimum inapproximability results for finding minimum hidden guard sets in polygons and terrains, in: SWAT  ...  We study the problem MINIMUM HIDDEN GUARD SET, which consists of positioning a minimum number of guards in a given polygon (or other structure such as a terrain) such that no two guards see each other  ...  guard set of size (t), where parameter t n will be defined as part of the rake-gadget in the construction.  ... 
doi:10.1016/j.comgeo.2006.01.004 fatcat:fhr3j7k43rehfa7kzhvowlhloy

Faster transport through slower runs: ant relocation dynamics in nature

Karunakaran Anoop, Ghosh Purbayan, Annagiri Sumana
2021 figshare.com  
Analysis of more than 1000 transports across eight relocating colonies reveals that they have a path efficiency of 85%.  ...  This investigation of ants performing tandem runs through heterogeneous terrains showcases the exceptionally efficient recruitment dynamics during colony relocation.  ...  Times have been calculated based on the speed and path efficiency for each of the terrain types.  ... 
doi:10.6084/m9.figshare.13516530.v1 fatcat:jdirgf5zhrdxjjhfvrmp3bjhsm

Sweeping a terrain by collaborative aerial vehicles

Alon Efrat, Mikko Nikkilä, Valentin Polishchuk
2013 Proceedings of the 21st ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems - SIGSPATIAL'13  
We give algorithms for motion planning and coordination for a team of UAVs under various assumptions on the vehicles equipage/capabilities and present outputs of an implementation of the algorithms.  ...  Mountainous regions are typically hard to access by land; because of this, search operations in hilly terrains are often performed by airborne force such as Unmanned Aerial Vehicles (UAVs).  ...  Unfortunately, the running time for computing π2, following from our analysis, is O(n 13+ε ).  ... 
doi:10.1145/2525314.2525355 dblp:conf/gis/EfratNP13 fatcat:rvj7m3y2ufc3lobsviieyeipk4

Use of Alternative Means of Movement in Tactical Tasks of Czech Army Units

Pavel Zahradníček, Luděk Rak, Zdeněk Flasar
2021 Transportation Research Procedia  
By incorporating internal principles and models, the authors also present calculation standards for planning operations using e-bikes.  ...  By incorporating internal principles and models, the authors also present calculation standards for planning operations using e-bikes.  ...  Generalization of measured results The patrolled area comprised 10% of rough off-road terrain, 20% of very easily passable terrain, and 70% of terrain passable for a passenger car with limitations, i.e  ... 
doi:10.1016/j.trpro.2021.06.023 fatcat:djyfgu6b6nekradet6agzzmnum

Front Matter, Table of Contents, Preface, Conference Organization

Susanne Albers, Susanne Albers
2020 Scandinavian Workshop on Algorithm Theory  
Parameter Analysis for Guarding Terrains Akanksha Agrawal, Sudeshna Kolay, and Meirav Zehavi . . . . . . . . . . . . . . . . . . . . . . . . . .  ...  Wisconsin-Madison) Anca Muscholl (University Bordeaux) Luke Ong (University of Oxford) Catuscia Palamidessi (INRIA) ISSN 1868-8969 https://www.dagstuhl.de/lipics S WAT 2 0 2 0 0:ix Invited Talks Parameterized  ... 
doi:10.4230/lipics.swat.2020.0 dblp:conf/swat/X20 fatcat:fixnehua6fajlmgidegp3smd2i

The Continuous 1.5D Terrain Guarding Problem: Discretization, Optimal Solutions, and PTAS [article]

Stephan Friedrichs and Michael Hemmer and James King and Christiane Schmidt
2016 arXiv   pre-print
In the NP-hard continuous 1.5D Terrain Guarding Problem (TGP) we are given an x-monotone chain of line segments in R^2 (the terrain T) and ask for the minimum number of guards (located anywhere on T) required  ...  Furthermore, we propose several filtering techniques reducing the size of our discretization, allowing us to devise an efficient IP-based algorithm that reliably provides optimal guard placements for terrains  ...  [29] showed that the TGP is fixed-parameter tractable w.r.t. the depth of terrain onion peeling, the number of layers of upper convex hulls induced by a terrain.  ... 
arXiv:1509.08285v3 fatcat:pe2cxjo2gbf3hn5nxirgm2knva

Inapproximability of finding maximum hidden sets on polygons and terrains

Stephan Eidenbenz
2002 Computational geometry  
This is already true for a simple polygon with holes (instead of a terrain).  ...  How many people can hide in a given terrain, without any two of them seeing each other?  ...  There are some upper and lower bound results on the number of guards needed for several kinds of guards to collectively cover all of a given terrain [2] .  ... 
doi:10.1016/s0925-7721(01)00029-3 fatcat:mnyh2oz7vnbybduglp73qwuhqq

Coverage optimization to support security monitoring

Alan T. Murray, Kamyoung Kim, James W. Davis, Raghu Machiraju, Richard Parent
2007 Computers, Environment and Urban Systems  
Thus, an approach is detailed for supporting security monitoring.  ...  important aspects of the security sensor placement problem can be modeled using the maximal covering location problem (MCLP) and/or the backup coverage location problem (BCLP) combined with visibility analysis  ...  Acknowledgements Funding for this research was provided by the National Science Foundation (Information Technology Research for National Priorities) under Grant IIS-0428249.  ... 
doi:10.1016/j.compenvurbsys.2006.06.002 fatcat:kycptldfl5azpcctolwej77ua4
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