The Triangle Collapse Algorithm Based on Angle Error Metrics

To solve the problems in the mesh simplification,such as the poor features preserving and too uniform in some areas,an improved triangle collapse algorithm based on angle error metrics is proposed.First,divide the triangles into three types,and different processing methods are adopted for different types of triangles.The algorithm uses the triangle collapse based on the quadratic error metrics.In order to preserving the topological structure and geometric boundary feature of the original model,the angle error metrics is added as a new feature factor on the basis of the two factors:the long and narrow degree and the local region area.This algorithm is implemented by VC++6.0 and OpenGL.The experiment shows that the algorithm preserves the boundary feature and topology of the original model well,and the speed of simplification is faster than other algorithm.

Research of Constructing 3D Digital River Based on ArcEngine and SketchUp

With the development of the 3D GIS and the digital basin, it is important for us to deal with the rivers from the 3D space. Compared to traditional forms of 2D GIS, the 3D GIS system brings better user experience for us. After introducing the current development status of the 3D digital river, the paper proposes a novel method for constructing 3D digital river system. It explores the methods in 3D digital river modeling by SketchUp, driving 3D scene by ArcScene and secondary developing by ArcGIS Engine. It discusses the specific issues of 3D river modeling with a river in Nanjing, and sums up a complete 3D modeling of operational process. Finally, that proves the feasibility of the method.

Anatomy and surgery of pure neuroendoscopic infratentorial supracerebellar approach for resection of pineal region tumor

Background: The pineal region tumors are surrounded by important structures. Neuroendoscopy has been increasingly used at home and abroad. This study is to simulate pure neuroendoscopic infratentorial supracerebellar approach for resection of pineal region tumor from the cadaveric head, and discuss the advantages and safety through this corridor. Methods: The anatomical structure for resection of pineal region tumor was visualized through pure neuroendoscopic infratentorial supracerebellar approach in three cadaveric heads. Three cases with pineal region tumors were retrospectively analyzed and summarized between June 2017 and December 2017. All cases were operated through pure neuroendoscopic infratentorial supracerebellar approach in the first affiliated hospital of Fujian medical university. Results: The anatomical structures of pineal region can be completely visualized by pure neuroendoscopic infratentorial supracerebellar corridor in the cadaveric head. Among the three cases, the first case was total resection, the second case was subtotal resection and the last case was partial resection. The postoperative pathology revealed cavernous hemangioma, germinoma and yolk sac tumor, respectively. The patients were followed-up for 1-6 months and had normal life.The KPS (karnofsky performance status) score was 100. Conclusion: The anatomical structure of the pineal region can be completely visualized and the tumor can be safely removed through pure neuroendoscopic infratentorial supracerebellar approach.

Endoscopically controlled surgery with open hemilaminectomy for the treatment of intradural extramedullary tumors:an operative technique and short-term outcomes of 20 consecutive cases

Background:To present a surgical technique for the treatment of intradural extramedullary(IDEM)tumors by using endoscopically controlled surgery with open hemilaminectomy technique.Methods:In this study,20 patients with 22 IDEM tumors were enrolled.An endoscopically controlled surgery with open hemilaminectomy was employed to remove the tumors.Data related to clinical symptoms and medical images before and after surgery were collected for perioperative evaluation and follow-up analysis.Results:All the tumors in 20 patients were well removed.The clinical symptoms were significantly reduced in all the patients as well.The short-term follow-up data showed that there was no tumor recurrence or spinal deformity.Conclusion:The endoscopically controlled surgery with open hemilaminectomy technique provided favorable exposure and satisfactory resection to the IDEM tumors.It may be an effective surgical method for treating IDEM tumors.Larger samples and longer follow-up data are needed to verify its long-term effectiveness.

UWB planar antenna technology

Recent developments of the ultra-wideband(UWB)planar antennas are reviewed,where the progress in UWB plate monopole antennas,UWB printed monopole antennas and the UWB printed slot antennas is introduced and compared.In addition,the UWB printed antennas with the band-notched functions are also presented.