Learn More
In wireless sensor networks (WSNs), there are numerous factors that may cause network congestion problems, such as the many-to-one communication modes, mutual interference of wireless links, dynamic changes of network topology and the memory-restrained characteristics of nodes. All these factors result in a network being more vulnerable to congestion. In(More)
In light of the problems of low recognition efficiency, high false rates and poor localization accuracy in traditional pipeline security detection technology, this paper proposes a type of hierarchical leak detection and localization method for use in natural gas pipeline monitoring sensor networks. In the signal preprocessing phase, original monitoring(More)
A limit DV-hop (LDV-hop) algorithm is put forward based on comprehensive analysis of DV-hop localization algorithms, in order to satisfy the characters of low cost and low power in WSNs. The least hop number between nodes and landmarks is counted firstly and the distance in hops is then computed. Finally the coordinates of nodes are determined. LDV-hop(More)
We cultured bone marrow-derived endothelial progenitor cells by a simple ex vivo expansion method and observed the expansion efficacy. Bone marrow mononuclear cells from five mongrel adult dogs were cultured with EGM-2MV medium in culture flasks coated with fibronectin. Morphology was observed with phase contrast microscopy, and a growth curve was(More)
OBJECTIVE To explore the effective surgical approaches in treating subclavian artery occlusion. METHODS Between December 2005 and February 2010, 53 patients with subclavian artery occlusion were treated, including left subclavian artery occlusion (35 cases) and stenosis (5 cases), right subclavian artery occlusion (5 cases) and stenosis (4 cases), and(More)
OBJECTIVE To investigate the effect of surface property of different polyether-ester block copolymers [poly(ethylene glycol-terephthalate)/poly(butylene terephthalate), PEGT/PBT] on the growth of smooth muscle cells (SMCs) and endothelial cells(ECs). METHODS Three kinds of copolymers were synthesized, which were 1000-T20 (group A), 1000PEGT70/PBT30 (group(More)
Topology control is one of the key technologies in ad hoc network. Recently some topology control algorithms focus on reducing the end-to-end delay have been proposed. However, they do not consider the delay which is caused by contending for the shared channel and collision at MAC layer. In this paper, we put forward a new delay model to character the link(More)
BACKGROUND Totally laparoscopic aortoiliac surgery has been newly developed in China. It is known as the most complex laparoscopic technique to learn because of its high-risk procedures. Analysis of the operation-related complications of this surgery is supposed to be helpful for the early success of this technique. METHODS Twelve male patients (56-70(More)