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52
Minimum Manhattan Network is NPComplete
"... A rectilinear path between two points p,q ∈ R 2 is a path connecting p and q with all its line segments horizontal or vertical segments. Furthermore, a Manhattan path between p and q is a rectilinear path with its length exactly dist(p, q): = p.x − q.x  + p.y − q.y. Given a set T of n points in ..."
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Cited by 8 (0 self)
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A rectilinear path between two points p,q ∈ R 2 is a path connecting p and q with all its line segments horizontal or vertical segments. Furthermore, a Manhattan path between p and q is a rectilinear path with its length exactly dist(p, q): = p.x − q.x  + p.y − q.y. Given a set T of n points in R 2, a network G is said to be a Manhattan network on T, if for all p, q ∈ T there exists a Manhattan path between p and q with all its line segments in G. For the given point set T, the Minimum Manhattan Network (MMN) Problem is to find a Manhattan network G on T with the minimum network length. In this paper, we shall prove that the decision version of MMN is strongly NPcomplete, using the reduction from the wellknown 3SAT problem, which requires a number of gadgets. The gadgets have similar structures, but play different roles in simulating the 3SAT formula. The reduction has been implemented with a computer program.
A fast 2approximation algorithm for the minimum Manhattan network problem
 In Proceedings of the 4th International Conference on Algorithmic Aspects in Information Management
, 2008
"... Abstract. Given a set T of n points in IR 2, a Manhattan Network G is a network with all its edges horizontal or vertical segments, such that for all p,q ∈ T, in G there exists a path (named a Manhattan path) of the length exactly the Manhattan distance between p and q. The Minimum Manhattan Network ..."
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Cited by 5 (2 self)
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Abstract. Given a set T of n points in IR 2, a Manhattan Network G is a network with all its edges horizontal or vertical segments, such that for all p,q ∈ T, in G there exists a path (named a Manhattan path) of the length exactly the Manhattan distance between p and q. The Minimum Manhattan Network (MMN) problem is to find a Manhattan network of the minimum length, i.e., the total length of the segments of the network is to be minimized. In this paper we present a 2approximation algorithm with time complexity O(n 2), which improves the 2approximation algorithm with time complexity Ω(n 8), proposed by Chepoi, Nouioua et al.. To the best of our knowledge, this is the best result on this problem. 1
Greedy construction of 2approximation minimum Manhattan network
 IN: PROCEEDINGS OF THE 19TH INTERNATIONAL SYMPOSIUM ON ALGORITHMS AND COMPUTATION
, 2008
"... Given a set T of n points in IR 2, a Manhattan Network G is a network with all its edges horizontal or vertical segments, such that for all p, q ∈ T, in G there exists a path (named a Manhattan path) of the length exactly the Manhattan distance between p and q. The Minimum Manhattan Network proble ..."
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Cited by 4 (1 self)
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Given a set T of n points in IR 2, a Manhattan Network G is a network with all its edges horizontal or vertical segments, such that for all p, q ∈ T, in G there exists a path (named a Manhattan path) of the length exactly the Manhattan distance between p and q. The Minimum Manhattan Network problem is to find a Manhattan network of the minimum length, i.e., the total length of the segments of the network is to be minimized. In this paper we present a 2approximation algorithm with time complexity O(n log n), which improves the 2approximation algorithm with time complexity O(n²). Moreover, compared with other 2approximation algorithms employing linear programming or dynamic programming technique, it was first discovered that only greedy strategy suffices to get 2approximation network.
Physical activity during leisure and commuting in Tianjin, China
"... Objective To investigate physical activity during leisure time and commuting among persons aged 15–69 years in the urban population of Tianjin, China, and to assess its associations with demographic and healthrelated characteristics. Methods In 1996 a crosssectional survey of 2002 males and 1974 f ..."
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Objective To investigate physical activity during leisure time and commuting among persons aged 15–69 years in the urban population of Tianjin, China, and to assess its associations with demographic and healthrelated characteristics. Methods In 1996 a crosssectional survey of 2002 males and 1974 females provided information on physical activity during leisure time and commuting and on demographics and health behaviours. Findings No leisuretime physical activity was engaged in by 67 % of females and 61 % of males. However, only 4 % of females and 9 % of males reported an absence of physical activity during commuting. The mean duration of leisuretime physical activity for the whole population was about 10 min per day. The average commuting time on foot or by bicycle was about 30 min. Leisuretime physical activity was more frequent among highly educated people, people with high incomes, whitecollar workers, married people, nonsmokers, or people commuting on foot or by bicycle than among other people. Persons with low incomes, male bluecollar workers and married people were more likely than others to engage in 30 min or more per day of physical activity on foot or by bicycle when commuting.
Ultrabroad bandwidth and highly sensitive optical ultrasonic detector for photoacoustic imaging
 ACS Photon
, 2014
"... ABSTRACT: We demonstrate an ultrasonic detector with unprecedented broad bandwidth and high sensitivity, based on an imprinted polymer optical microring. It has an acoustic response of up to 350 MHz at −3 dB and noiselimited detectable pressure as low as 105 Pa in this frequency range. Application ..."
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Cited by 3 (2 self)
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ABSTRACT: We demonstrate an ultrasonic detector with unprecedented broad bandwidth and high sensitivity, based on an imprinted polymer optical microring. It has an acoustic response of up to 350 MHz at −3 dB and noiselimited detectable pressure as low as 105 Pa in this frequency range. Application of such a detector in photoacoustic imaging leads to improved axial resolving ability compared with using the conventional ultrasound detector, and sub3 μm axial resolution is achieved, which is more than a 2fold improvement with respect to the reported record. The device’s miniaturized cavity height guarantees its broadband response, and at the same time, its high optical quality factor ensures the detection sensitivity. Our work suggests that the polymerbased miniature microring resonator works as a highperformance ultrasound detector and has potential for acquiring volumetric photoacoustic images with cellular/subcellular resolution in three dimensions.
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"... Associations between socioeconomic status and cardiovascular risk factors in an urban ..."
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Associations between socioeconomic status and cardiovascular risk factors in an urban
75 Integrating Membrane Transport with Male Gametophyte Development and Function through Transcriptomics
"... Male fert l ty depends on the proper development of the male gametophyte, successful pollen germ nat on, tube growth and del very of the sperm cells to the ovule. Prev ous stud es have shown that nutr ents l ke boron, and on grad ents or currents of Ca 2+, H +, and K + are cr t cal for pollen tube g ..."
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Cited by 7 (1 self)
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Male fert l ty depends on the proper development of the male gametophyte, successful pollen germ nat on, tube growth and del very of the sperm cells to the ovule. Prev ous stud es have shown that nutr ents l ke boron, and on grad ents or currents of Ca 2+, H +, and K + are cr t cal for pollen tube growth. However, the molecular dent t es of transporters med at ng these fluxes are mostly unknown. As a first step to integrate transport with pollen development and function, a genomewide analys s of transporter genes expressed n the male gametophyte at four developmental stages was conducted. About 1269 genes encoding classified transporters were collected from the Arabidopsis thaliana genome. Of 757 transporter genes expressed in pollen, 16 % or 124 genes, including AHA6, CNGC18, TIP1.3 and CHX08, are specifically or preferentially expressed relative to sporophyt c t ssues. Some genes are h ghly expressed n m crospores and b cellular pollen (COPT3, STP2, OPT9); while others are act vated only n tr cellular or mature pollen (STP11, LHT7). Analyses of ent re gene fam l es showed that a subset of genes, nclud ng those expressed n sporophyt c t ssues, were developmentallyregulated dur ng pollen maturat on. Early and late express on patterns revealed by transcr ptome analys s are supported by promoter::GUS analyses of CHX genes and by other methods. Recent genet c stud es based on a few transporters, nclud ng plasma membrane H + pump AHA3, Ca 2+ pump ACA9, and K + channel SPIK, further support the express on patterns and the nferred funct ons revealed by our analyses. Thus, revealing the distinct expression patterns of specific transporters and unknown polytopic proteins during microgametogenesis prov des new ns ghts for strateg c mutant analyses necessary to ntegrate the roles of transporters and potent al receptors w th
Randomnessefficient Curve Sampling Thesis by
, 2014
"... ii Curve samplers are sampling algorithms that proceed by viewing the domain as a vector space over a finite field, and randomly picking a lowdegree curve in it as the sample. Curve samplers exhibit a nice property besides the sampling property: the restriction of lowdegree polynomials over the do ..."
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ii Curve samplers are sampling algorithms that proceed by viewing the domain as a vector space over a finite field, and randomly picking a lowdegree curve in it as the sample. Curve samplers exhibit a nice property besides the sampling property: the restriction of lowdegree polynomials over the domain to the sampled curve is still lowdegree. This property is often used in combination with the sampling property and has found many applications, including PCP constructions, local decoding of codes, and algebraic PRG constructions. The randomness complexity of curve samplers is a crucial parameter for its applications. It is known that (nonexplicit) curve samplers using O(logN + log(1/δ)) random bits exist, where N is the domain size and δ is the confidence error. The question of explicitly constructing randomnessefficient curve samplers was first raised in [TSU06] where they obtained curve samplers with nearoptimal randomness complexity. In this thesis, we present an explicit construction of lowdegree curve samplers with optimal randomness complexity (up to a constant factor) that sample curves of degree(
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"... Abstract. Candida glabrata infection following total hip arthroplasty is rare and, due to the insufficiency of standardized clinical and evidencebased guidelines, there is no appropriate therapeutic schedule. The present study reports the case of a 44yearold patient with Candida glabrata infecti ..."
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Abstract. Candida glabrata infection following total hip arthroplasty is rare and, due to the insufficiency of standardized clinical and evidencebased guidelines, there is no appropriate therapeutic schedule. The present study reports the case of a 44yearold patient with Candida glabrata infection following a total hip arthroplasty. The patient was successfully treated by administration of intravenous and oral voriconazole without removal of the prosthesis. This case illustrates the significance of postoperative followup, clinician experience and the choice of the correct antifungal agent. In this case, we found in the early stage of Candida glabrata infection, we were able to control the infection without surgery through thorough irrigation. This reduces patient suffering and economic burden.
Results 1  10
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52