Mapping the Mangrove Forest Restoration Potential and Conservation Gaps in China Based on Random Forest Model

Zhonghua Yu,Wei Li,Shaowei Zhang,Buqing Zhong,Jun Wang,이시영,최재혁,Shulin Deng 인간식물환경학회 2022 인간식물환경학회지 Vol.25 No.4

Background and objective: The area of mangroves is gradually decreasing globally, and mangroves are already one of the most threatened ecosystems. Despite net growth in the mangrove areas in China, the restoration potential of mangroves is still insufficient. This study proposed the Random forest model as an excellent data mining method to map the restoration potential based on the predicted probability of mangrove habitat suitability. Methods: We demonstrated the vital environmental variables influencing habitat suitability. The de-cisive advantages of RFM were parsimonious (variables selection), cost-effective (us-ing existing open-source data), accurate (training AUC was 0.89, testing AUC was 0.91), highly efficient (fast-training speed); and its results had high explanatory power. Here, we first mapped the conservation gaps using the RFM. Results: The results showed that temperature was the most important environmental factor influencing the habitat suit-ability of mangroves. The northern limit of suitable areas was around 24°44' N. The theoretical suitable habitat area for mangrove was 196,566.6 ha (the highly suitable area was 32,551.4 ha, the medium suitable area was 164,015.2 ha). The potential area for mangrove restoration was 176,264 ha (Guangdong with 104215.4 ha, Guangxi with 65957.5 ha). Conclusion: We proposed 24 sites with conservation gaps for mangrove forests restoration and nine potential sites as examples for the further restoration plan. We took one example site with high restoration potential for further explanation: how the key environmental factors influence the habitat suitability and how to use the infor-mation to guide the restoration strategies. RFM can be used as a data mining algo-rithm for the utmost use of the presence-only ecological data, objectively evaluating the suitability of species distribution, and providing scientifically technical data for species restoration planning.

Triqubit-state Measurement-based Image Edge Detection Algorithm

Zhonghua Wang,Faliang Huang 한국정보처리학회 2018 Journal of information processing systems Vol.14 No.6

Aiming at the problem that the gradient-based edge detection operators are sensitive to the noise, causing thepseudo edges, a triqubit-state measurement-based edge detection algorithm is presented in this paper. Combing the image local and global structure information, the triqubit superposition states are used torepresent the pixel features, so as to locate the image edge. Our algorithm consists of three steps. Firstly, theimproved partial differential method is used to smooth the defect image. Secondly, the triqubit-state ischaracterized by three elements of the pixel saliency, edge statistical characteristics and gray scale contrast toachieve the defect image from the gray space to the quantum space mapping. Thirdly, the edge image isoutputted according to the quantum measurement, local gradient maximization and neighborhood chaincode searching. Compared with other methods, the simulation experiments indicate that our algorithm hasless pseudo edges and higher edge detection accuracy.

Fenestrated Stent Graft Repair of Abdominal Aortic Aneurysm: Hemodynamic Analysis of the Effect of Fenestrated Stents on the Renal Arteries

Zhonghua Sun,Thanapong Chaichana 대한영상의학회 2010 Korean Journal of Radiology Vol.11 No.1

Objective: We wanted to investigate the hemodynamic effect of fenestrated stents on the renal arteries with using a fluid structure interaction method. Materials and Methods: Two representative patients who each had abdominal aortic aneurysm that was treated with fenestrated stent grafts were selected for the study. 3D realistic aorta models for the main artery branches and aneurysm were generated based on the multislice CT scans from two patients with different aortic geometries. The simulated fenestrated stents were designed and modelled based on the 3D intraluminal appearance, and these were placed inside the renal artery with an intra-aortic protrusion of 5.0-7.0 mm to reflect the actual patients’treatment. The stent wire thickness was simulated with a diameter of 0.4 mm and hemodynamic analysis was performed at different cardiac cycles. Results: Our results showed that the effect of the fenestrated stent wires on the renal blood flow was minimal because the flow velocity was not significantly affected when compared to that calculated at pre-stent graft implantation, and this was despite the presence of recirculation patterns at the proximal part of the renal arteries. The wall pressure was found to be significantly decreased after fenestration, yet no significant change of the wall shear stress was noticed at post-fenestration, although the wall shear stress was shown to decrease slightly at the proximal aneurysm necks. Conclusion: Our analysis demonstrates that the hemodynamic effect of fenestrated renal stents on the renal arteries is insignificant. Further studies are needed to investigate the effect of different lengths of stent protrusion with variable stent thicknesses on the renal blood flow, and this is valuable for understanding the long-term outcomes of fenestrated repair. Objective: We wanted to investigate the hemodynamic effect of fenestrated stents on the renal arteries with using a fluid structure interaction method. Materials and Methods: Two representative patients who each had abdominal aortic aneurysm that was treated with fenestrated stent grafts were selected for the study. 3D realistic aorta models for the main artery branches and aneurysm were generated based on the multislice CT scans from two patients with different aortic geometries. The simulated fenestrated stents were designed and modelled based on the 3D intraluminal appearance, and these were placed inside the renal artery with an intra-aortic protrusion of 5.0-7.0 mm to reflect the actual patients’treatment. The stent wire thickness was simulated with a diameter of 0.4 mm and hemodynamic analysis was performed at different cardiac cycles. Results: Our results showed that the effect of the fenestrated stent wires on the renal blood flow was minimal because the flow velocity was not significantly affected when compared to that calculated at pre-stent graft implantation, and this was despite the presence of recirculation patterns at the proximal part of the renal arteries. The wall pressure was found to be significantly decreased after fenestration, yet no significant change of the wall shear stress was noticed at post-fenestration, although the wall shear stress was shown to decrease slightly at the proximal aneurysm necks. Conclusion: Our analysis demonstrates that the hemodynamic effect of fenestrated renal stents on the renal arteries is insignificant. Further studies are needed to investigate the effect of different lengths of stent protrusion with variable stent thicknesses on the renal blood flow, and this is valuable for understanding the long-term outcomes of fenestrated repair.

A New Recursive Least-Squares Algorithm based on Matrix Pseudo Inverses (ICCAS 2003)

Zhonghua Quan,Soohee Han,Wookhyun Kwon 제어로봇시스템학회 2003 제어로봇시스템학회 국제학술대회 논문집 Vol.2003 No.10

The nonlinear galloping of iced transmission conductor under uniform and turbulence wind

Zhonghua Liu,Chenhui Ding,Jian Qin,Ying Lei 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.75 No.4

The analytical approach for stability and response of iced conductor under uniform wind or turbulent wind is presented in this study. A nonlinear dynamic model is established to describe the motion of iced conductor galloping. In the case of uniform wind, the stability condition is derived by analyzing the eigenvalue associated with linearized matrix; The first order and second order approximation of galloping amplitude are obtained using multi-scale method. However, real wind has random characteristics essentially. To accurately evaluate the performance of the galloping iced conductor, turbulence wind should be described by random processes. In the case of turbulence wind, the Lyapunov exponent is conducted to judge the stability condition; The probability density of displacement is obtained by using the path integral method to predict galloping amplitude. An example is proposed to verify the effectiveness of the previous methods. It is shown that the fluctuating component of wind has little influence on the stability of iced conductor, but it can increase galloping amplitude. The analytical results on stability and response are also verified by numerical time stepping method.

Robust FIR ¯lter for Linear Discrete-time System

Zhonghua Quan,Soohee Han,Wook Hyun Kwon 제어로봇시스템학회 2005 제어로봇시스템학회 국제학술대회 논문집 Vol.2005 No.6

Parallel Implementation of M-Step Kalman FIR Filter for Linear Discrete Time-invariant Systems

Zhonghua Quan,Sheng Ai Xuan,Soohee Han,Wook Hyun Kwon 제어로봇시스템학회 2006 제어로봇시스템학회 국제학술대회 논문집 Vol.2006 No.10

Multislice CT Virtual Intravascular Endoscopy for Assessing Pulmonary Embolisms: a Pictorial Review

Zhonghua Sun,Sultan Ayed Al Dosari,Curtise Ng,Ali al-Muntashari,Saud Almaliky 대한영상의학회 2010 Korean Journal of Radiology Vol.11 No.2

Multislice CT has been widely used in clinical practice for diagnosing cardiovascular disease due to its reduced invasiveness and its high spatial and temporal resolution. As a reliable alternative to conventional pulmonary angiography, multislice CT angiography has been recognized as the first line technique for detecting and diagnosing pulmonary embolism. A pulmonary embolism located in the main pulmonary artery, as well as being located in the segmental branches, can be accurately detected with multislice CT imaging, and especially with the use of 16-and 64-slice CT scanners. Visualization of pulmonary embolisms has traditionally been limited to 2D, multiplanar reformation and the 3D external surface visualizations. In this pictorial review, we present our experience of using 3D virtual intravascular endoscopy to characterize and evaluate the intraluminal appearance of pulmonary embolisms in a group of patients who were suspected of having pulmonary embolism and who were undergoing multislice CT angiography. We expect that the research findings from this study will provide insight into the extent of disease and the luminal changes to the pulmonary arteries that are due to the presence of thrombus, and so monitoring of the progress of disease and predicting the treatment outcome can well be achieved.

Multislice CT Angiography of Fenestrated Endovascular Stent Grafting for Treating Abdominal Aortic Aneurysms: a Pictorial Review of the 2D/3D Visualizations

Zhonghua Sun,Bibombe P Mwipatayi,Yvonne B Allen,David E Hartley,Michael M Lawrence-Brown 대한영상의학회 2009 Korean Journal of Radiology Vol.10 No.3

Fenestrated endovascular repair of an abdominal aortic aneurysm has been developed to treat patients with a short or complicated aneurysm neck. Fenestration involves creating an opening in the graft fabric to accommodate the orifice of the vessel that is targeted for preservation. Fixation of the fenestration to the renal arteries and the other visceral arteries can be done by implanting bare or covered stents across the graft-artery ostia interfaces so that a portion of the stent protrudes into the aortic lumen. Accurate alignment of the targeted vessels in a longitudinal aspect is hard to achieve during stent deployment because rotation of the stent graft may take place during delivery from the sheath. Understanding the 3D relationship of the aortic branches and the fenestrated vessel stents following fenestration will aid endovascular specialists to evaluate how the stent graft is situated within the aorta after placement of fenestrations. The aim of this article is to provide the 2D and 3D imaging appearances of the fenestrated endovascular grafts that were implanted in a group of patients with abdominal aortic aneurysms, based on the multislice CT angiography. The potential applications of each visualization technique were explored and compared with the 2D axial images.

The Guaranteed Bound of Horizon Size for the Stabilizing Receding Horizon Control

ZhongHua Quan,SooHee Han,WookHyun Kwon 제어로봇시스템학회 2004 제어로봇시스템학회 국제학술대회 논문집 Vol.2004 No.8