scholarly journals Efficient algorithms for the one-dimensional k-center problem

2015 ◽  
Vol 592 ◽  
pp. 135-142 ◽  
Author(s):  
Danny Z. Chen ◽  
Jian Li ◽  
Haitao Wang
2016 ◽  
Vol 26 (03n04) ◽  
pp. 185-210
Author(s):  
Haitao Wang ◽  
Jingru Zhang

The (weighted) [Formula: see text]-median, [Formula: see text]-means, and [Formula: see text]-center problems in the plane are known to be NP-hard. In this paper, we study these problems with an additional constraint that requires the sought [Formula: see text] facilities to be on a given line. We present efficient algorithms for various distance measures such as [Formula: see text]. We assume that all [Formula: see text] weighted points are given sorted by their projections on the given line. For [Formula: see text]-median, our algorithms for [Formula: see text] and [Formula: see text] metrics run in [Formula: see text] time and [Formula: see text] time, respectively. For [Formula: see text]-means, which is defined only on the squared [Formula: see text] distance, we give an [Formula: see text] time algorithm. For [Formula: see text]-center, our algorithms run in [Formula: see text] time for all three metrics, and in [Formula: see text] time for the unweighted version under [Formula: see text] and [Formula: see text] metrics. While our results for the [Formula: see text]-center problem are optimal, the results for the [Formula: see text]-median problem almost match the best algorithms for the corresponding one-dimensional problems.


2008 ◽  
Vol 67 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Stefano Passini

The relation between authoritarianism and social dominance orientation was analyzed, with authoritarianism measured using a three-dimensional scale. The implicit multidimensional structure (authoritarian submission, conventionalism, authoritarian aggression) of Altemeyer’s (1981, 1988) conceptualization of authoritarianism is inconsistent with its one-dimensional methodological operationalization. The dimensionality of authoritarianism was investigated using confirmatory factor analysis in a sample of 713 university students. As hypothesized, the three-factor model fit the data significantly better than the one-factor model. Regression analyses revealed that only authoritarian aggression was related to social dominance orientation. That is, only intolerance of deviance was related to high social dominance, whereas submissiveness was not.


2011 ◽  
Vol 35 (1) ◽  
pp. 15-27
Author(s):  
Zoran Ivić ◽  
Željko Pržulj

Adiabatic large polarons in anisotropic molecular crystals We study the large polaron whose motion is confined to a single chain in a system composed of the collection of parallel molecular chains embedded in threedimensional lattice. It is found that the interchain coupling has a significant impact on the large polaron characteristics. In particular, its radius is quite larger while its effective mass is considerably lighter than that estimated within the one-dimensional models. We believe that our findings should be taken into account for the proper understanding of the possible role of large polarons in the charge and energy transfer in quasi-one-dimensional substances.


1983 ◽  
Vol 4 ◽  
pp. 297-297
Author(s):  
G. Brugnot

We consider the paper by Brugnot and Pochat (1981), which describes a one-dimensional model applied to a snow avalanche. The main advance made here is the introduction of the second dimension in the runout zone. Indeed, in the channelled course, we still use the one-dimensional model, but, when the avalanche spreads before stopping, we apply a (x, y) grid on the ground and six equations have to be solved: (1) for the avalanche body, one equation for continuity and two equations for momentum conservation, and (2) at the front, one equation for continuity and two equations for momentum conservation. We suppose the front to be a mobile jump, with longitudinal velocity varying more rapidly than transverse velocity.We solve these equations by a finite difference method. This involves many topological problems, due to the actual position of the front, which is defined by its intersection with the reference grid (SI, YJ). In the near future our two directions of research will be testing the code on actual avalanches and improving it by trying to make it cheaper without impairing its accuracy.


2019 ◽  
Vol 67 (6) ◽  
pp. 483-492
Author(s):  
Seonghyeon Baek ◽  
Iljae Lee

The effects of leakage and blockage on the acoustic performance of particle filters have been examined by using one-dimensional acoustic analysis and experimental methods. First, the transfer matrix of a filter system connected to inlet and outlet pipes with conical sections is measured using a two-load method. Then, the transfer matrix of a particle filter only is extracted from the experiments by applying inverse matrices of the conical sections. In the analytical approaches, the one-dimensional acoustic model for the leakage between the filter and the housing is developed. The predicted transmission loss shows a good agreement with the experimental results. Compared to the baseline, the leakage between the filter and housing increases transmission loss at a certain frequency and its harmonics. In addition, the transmission loss for the system with a partially blocked filter is measured. The blockage of the filter also increases the transmission loss at higher frequencies. For the simplicity of experiments to identify the leakage and blockage, the reflection coefficients at the inlet of the filter system have been measured using two different downstream conditions: open pipe and highly absorptive terminations. The experiments show that with highly absorptive terminations, it is easier to see the difference between the baseline and the defects.


2014 ◽  
Vol 35 (3) ◽  
pp. 568-574 ◽  
Author(s):  
Zhi-zhen Zhu ◽  
Zhi-da Zhang ◽  
Fa-lin Liu ◽  
Bin-bing Li ◽  
Chong-bin Zhou

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