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- 저자 : Rufei Liu (검색결과 4 건)
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Energy-Aware Preferential Attachment Model for Wireless Sensor Networks with Improved Survivability
( Rufei Ma ),( Erwu Liu ),( Rui Wang ),( Zhengqing Zhang ),( Kezhi Li ),( Chi Liu ),( Ping Wang ),( Tao Zhou ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.7
Recent years have witnessed a dramatic increase in topology research of wireless sensor networks (WSNs) where both energy consumption and survivability need careful consideration. To balance energy consumption and ensure survivability against both random failures and deliberate attacks, we resort to complex network theory and propose an energy-aware preferential attachment (EPA) model to generate a robust topology for WSNs. In the proposed model, by taking the transmission range and energy consumption of the sensor nodes into account, we combine the characters of Erdos -Renyi (ER) model and Barabasi-Albert (BA) model in this new model and introduce tunable coefficients for balancing connectivity, energy consumption, and survivability. The correctness of our theoretic analysis is verified by simulation results. We find that the topology of WSNs built by EPA model is asymptotically power-law and can have different characters in connectivity, energy consumption, and survivability by using different coefficients. This model can significantly improve energy efficiency as well as enhance network survivability by changing coefficients according to the requirement of the real environment where WSNs deployed and therefore lead to a crucial improvement of network performance.
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Jingpeng Liu,Peng Huang,Xiaoqing Zhang,Yong Chen,Xin Zheng,Rufei Shen,Xuefeng Tang,Hui Yang,Song Li 대한신경외과학회 2023 Journal of Korean neurosurgical society Vol.66 No.1
Objective : Ischemia and hemorrhage of pituitary adenomas (PA) caused important clinical syndrome. However, the differences on clinical characteristics and surgical outcomes between these two kinds apoplexy were less reported. Methods : A retrospective analysis was made of patients with pituitary apoplexy between January 2013 and June 2018. Baseline and clinical characteristics before surgery were reviewed. All patients underwent transsphenoidal surgery and were followed up at least 1 year. Results : Total 67 cases (5.8%) among 1147 pituitary tumor patients were enrolled, which consisted of 28 (~2.4%) ischemic PA and 39 (~3.4%) hemorrhagic PA. There were more male patients in the ischemic group compared with hemorrhagic group (78.6% vs 53.8%, p=0.043). However, the mean age, tumor size and functional tumor ratio were significant higher in the hemorrhagic group. Headache was more common in ischemic PA (82.1%) than that of hemorrhagic PA (51.3%, p=0.011). Magnetic resonance imaging findings found that mucosal thickening and enhancement of the sphenoid sinus was observed in 15 ischemic PA patients (n=27, 55.6%), but none in patients with hemorrhagic PA (n=38, p<0.0001). It was worth noting that the rate of pre-surgical hypopituitarism in ischemic PA patients were seemed higher than that in hemorrhagic PA patients, but not significant. The two groups got a total tumor resection rate at 94.1% and 92.9%, independently. No significant difference on the operative time, blood loss in operation and complications in perioperative period was observed in two groups. After operation, cranial nerve symptoms recovered to normal at 81.8% of ischemic PA patients and 82.6% of hemorrhagic PA patients. Importantly, the incidence of postoperative hypopituitarism partially decreased in both groups, among which the rate of hypothyroidism in ischemic PA patients significantly decreased from 46.4% to 18.5% (p=0.044). Conclusion : Patients with ischemic PA presented different clinical characteristics to the hemorrhagic ones. Transsphenoidal surgery should be considered for the patients with neuro-ophthalmic deficits and might benefit for pituitary function recovery of the apoplectic adenoma patients, especially pituitary thyroid axis in ischemic PA patients.
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Automatic Extraction Method of Urban Road Curb Boundary from Vehicle-borne Laser Point Clouds
Hongwei Ren,Rufei Liu,Fei Wang,Jiben Yang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.8
With the acceleration of urbanization, urban road networks are being extended and updated at an alarming rate. How to extract the boundary information of the urban road network efficiently and scientifically to support fine urban management has become a difficult problem. Vehicle-Borne Mobile Mapping System can quickly and efficiently obtain 3D road data, and further realize the extraction of urban road boundary. Based on the tracking information of the Vehicle-Borne Mobile Mapping System, this paper extracts contiguous laser scanning lines from vehicle-borne mobile laser scanning data. By further analyzing the spatial geometric distribution features of the point clouds on different terrain of scan lines, this paper proposes an adaptive window clustering classification method based on the scan line index to solve the problem of the automatic extraction of urban road curb boundary. Experiments are carried out on two point clouds data obtained by the vehicle-borne mobile measurement system. And the accuracy of the extraction of curbs boundary is 99%. The experiment results show that this method can effectively reduce the interference of road noise points as well as the influence of facade features on the boundary extraction of curbs and adapt to different shapes and distribution conditions of urban roads curbs.
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Bori Cong,Qingying Li,Rufei Liu,Fei Wang,Danyang Zhu,Jiben Yang 대한토목학회 2022 KSCE Journal of Civil Engineering Vol.26 No.12
Mobile laser scanning can quickly and dynamically obtain a wide range of urban scene point clouds. However, due to factors such as occlusion and field of view limitation, it needs to be supplemented by terrestrial laser scanning. The acquisition methods and data quality of mobile point clouds and terrestrial point clouds are quite different, the target of urban scene point clouds is complex and diverse, and the corresponding feature is difficult to extract, so the point cloud fusion is difficult. To this end, a point cloud registration method of mobile and terrestrial scanning based on the target features of artificial ground objects is proposed. Firstly, the data features of mobile laser scanning point clouds and terrestrial laser scanning point clouds are analyzed, and the point clouds are diluted with equal density. Then, the artificial ground objects are extracted as the registration primitives to reduce the scene complexity, and the features of urban scenes and the features of point cloud eigenvalues and principal curvature attributes are analyzed. Combined with the octree voxel index, the multi-scale key point extraction method is constructed to extract the multi-scale key points of registration primitives. Finally, the key point constraint is used to improve the deficiencies of 4PCS (4-Points Congruent Sets) algorithm and ICP (Iterative Closest Point) algorithm to complete the registration of mobile and terrestrial point clouds in different road scenes. Experiments show that the point cloud registration accuracy can reach 2.6 cm, which provides a feasible method for high precision fusion of multi-platform laser point clouds.
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