There has been significant success in designing highly efficient algorithms for distance and shortest-path queries in recent years; many of the state-of-the-art algorithms use the hub labeling framework. In this paper, we study the approximability of the Hub Labeling problem. We prove a hardness of Ω(log n) for Hub Labeling, matching known approximation guarantees. The hardness result applies t...

the problem of staff scheduling at a truck hub for loading and stripping of the trucks is an important and difficult problem to optimize the labor efficiency and cost. the trucks enter the hub at different hours a day, in different known time schedules and operating hours. in this paper, we propose a goal programming to maximize the labor efficiency via minimizing the allocation cost. the propo...

BACKGROUND AND PURPOSE Acute stroke clinical trials are conducted primarily at academic medical centers. As a result, patients living in rural areas are excluded from participation, results may not be generalizable to nonacademic settings, and studies may be slow to recruit subjects. Telemedicine can provide rural patients with emergency neurovascular consultation. We sought to determine whethe...

The principle of the harmonic analysis method and the its application in the hub runout measurement are introduced in detail in this article, and through the practical measurement data, the geometric meaning of judge the hub quality by the harmonic analysis method is proposed, and the disadvantages of the 8-point coordinate method are analyzed, and the computation method of the Fourier factor i...

Alzheimer's disease (AD) is a progressive neurodegenerative disease involving the alteration of gene expression at the whole genome level. Genome-wide transcriptional profiling of AD has been conducted by many groups on several relevant brain regions. However, identifying the most critical dys-regulated genes has been challenging. In this work, we addressed this issue by deriving critical genes...

Transport networks with hub structure organise the exchange of shipments between many sources and sinks. All sources and sinks are connected to a small number of hubs which serve as transhipment points, so that only few, strongly consolidated transport relations exist. While hubs and detours lead to additional costs, the savings from bundling shipments, i.e. economies of scale, usually outweigh...

A fundamental question is how complex structures are maintained after their initial specification. Stem cells reside in a specialized microenvironment, called niche, which provides essential signals controlling stem cell behavior. We addressed this question by studying the Drosophila male stem cell niche, called the hub. Once specified, the hub cells need to maintain their position and architec...

The niche directs key behaviors of its resident stem cells, and is thus crucial for tissue maintenance, repair and longevity. However, little is known about the genetic pathways that guide niche specification and development. The male germline stem cell niche in Drosophila houses two stem cell populations and is specified within the embryonic gonad, thus making it an excellent model for studyin...

This paper addresses the classical single and multiple allocation hub location problems with fully interconnected hubs, in which balanced round-trip flows on links are considered strategic decision making process. The use of is motivated by need to decrease empty-trip rate vehicles increase full-load vehicles. Mixed-integer programming models presented for versions problems. Numerical experimen...