Experiments on Road Extraction from Remote Sensing Images using SVM combined with FCM and MRF

Jiawei Xu,Seop Hyeong Park 한국멀티미디어학회 2010 한국멀티미디어학회 학술발표논문집 Vol.2010 No.2

This paper presents an approach to road extraction from remote sensing images. The proposed algorithm consists of three steps. In the first step, fuzzy C-means(FCM) clustering method roughly classifies the pixels in input image to several classes. A probabilistic support vector machine(SVM) is, then, applied to classify each pixel into road or non-road class. In the final step, Markov random field(MRF) regularization is used to refine the classification results attained in the second step. Experimental results with real images are presented and compared with those obtained from several road extraction techniques. Experimental results show that the proposed algorithm outperforms several methods we compare with in terms of rank distance and quality percentage.

Eye Fixation Location Recommendation in Advanced Driver Assistance System

Jiawei Xu,Kun Guo,Federica Menchinelli,박섭형 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.2

Recent research progress on the approach of visual attention modeling for mediated perception to advanced driver assistance system (ADAS) has drawn the attention of computer and human vision researchers. However, it is still debatable whether the actual driver’s eye fi xation locations (EFLs) or the predicted EFLs which are calculated by computational visual attention models (CVAMs) are more reliable for safe driving under real-life driving conditions. We analyzed the suitability of the following two EFLs using ten typical categories of natural driving video clips: the EFLs of human drivers and the EFLs predicted by CVAMs. In the suitability analysis, we used the EFLs confi rmed by two experienced drivers as the reference EFLs. We found that both approaches alone are not suitable for safe driving and EFL suitable for safe driving depends on the driving conditions. Based on this fi nding, we propose a novel strategy for recommending one of the EFLs to the driver for ADAS under predefi ned 10 real-life driving conditions. We propose to recommend one of the following 3 EFL modes for diff erent driving conditions: driver’s EFL only, CVAM’s EFL only, and interchangeable EFL. In interchangeable EFL mode, driver’s EFL and CVAM’s EFL are interchangeable. The selection of two EFLs is a typical binary classifi cation problem, so we apply support vector machines (SVMs) to solve this problem. We also provide a quantitative evaluation of the classifi ers. The performance evaluation of the proposed recommendation method indicates that it is potentially useful to ADAS for future safe driving.

탄소나노튜브 보강 고무 복합재료의 배향해석 및 물성평가

서가울(Jiawei Xu),이동주(Dong Joo Lee) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.4

The mechanical and electrical properties of carbon nano-tube(CNT)/silicone compo- site were investigated as functions of number of inlet, CNT content, length and specimen thickness. Also, a numerical analysis carried out using moldflow2011. The mechanical and electrical properties increase with the CNT’s orientation and content. For a two-inlet mold, the weld line is formed. However, the tensile strength increases and the electrical resistivity decreases with the weld line due to the high CNT concentration in this region. The tensile strength in the vertical of the orientation direction is about 10~20% low when it compared to the value in orientation direction. As the specimen thickness increases, the tensile strength of composites decreases due to the CNT orientation and skin effect. The fiber orientation tensor of 3.5㎜ thick specimen is found to be better than the case of 2㎜ or 5㎜ by the numerical analysis. Therefore, the specimen with t=3.5㎜ has the highest tensile strength and the lowest surface electrical resistivity under the same condition.

성형조건에 따른 탄소나노튜브 보강 고무의 물성 평가

쉬자웨이(Jiawei Xu),도탄쭝(Thanh Trung Do),이동주(Dong Joo Lee) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

The carbon nano-tube(CNT)/silicone composite is fabricated by the transfer molding(TM) under different molding conditions such as inlet number, CNT content and solvent percentage. Also, those conditions are compared as a function of specimen thickness. It is found that the alignment of CNT is dependent on the molding design and processing conditions. And, it affects the mechanical and electrical properties of composites. For the case of two-inlet, the weld line is formed when two separate flow fronts are travelled in the opposite directions and meet to create the bond area, which might degrade the tensile strength of composites. Also, bond areas provide the connection of CNT and give low electrical resistivity. In addition, the measured electrical resistivity (volume and surface) with the sample accommodated in the electrode for composites are reported and examined based on the numerical analysis.

Removal of norfloxacin by combining persulfate with nano zero-valent iron modified by activated carbon and copper nanocomposite

Jiawei Zhang,Yong Chen,Jingzhuo Liang,Hui Xu 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.5

Biomimetic functional hydrogel particles with enhanced adhesion characteristics for applications in fracture conformance control

Jiawei Liu,Lin Li,Zhongzheng Xu,Yongpeng Sun,Yining Wu,Caili Dai 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.106 No.-

Fracture conformance control in reservoir can effectively improve water channel to increase crude oil displacementefficiency of subsequent waterflooding. Inspired by the remarkable underwater wet adhesionof mussel byssus, hydrogel particles which can adhere stably on the fracture rock surface in reservoir conditionscould achieve long-lasting reservoir control effect. In this work, the size-controllable biomimeticfunctional hydrogel particles were prepared by mechanical shearing after bulk hydrogel was constructedby catechol-functionalized polyacrylamide and phenolic resin crosslinking agent. The influence of solutionsalinity on the aggregation and adhesion of hydrogel particles was investigated via scanning electronmicroscope (SEM), colloidal probe atomic force microscope (AFM) and quartz crystal microbalance withdissipation (QCM-D). The results showed that hydrogel particles maintained well-dispersed state in lowsalinitywater, while exhibited significant adhesion and adsorption capacity to the silica surface in simulatedreservoir salinity water. This is of great importance to the practical applications that the hydrogelparticles would not show enhanced adhesion to rock surfaces until the reservoir salinity water was met,which was beneficial to the in-depth migration of hydrogel particles to achieve effective deep reservoirprofile control. Furthermore, the visible micro-model was designed and applied to evaluate profile controleffect of hydrogel particles, and the results showed that hydrogel particles could withstand waterflushing and adhere stably to the fracture surface. The waterflooding sweep efficiency was increasedremarkably from 20.3% ± 2.0% to 38.8% ± 2.0%. This work would help better understand the functionmechanism of hydrogel particles in reservoir control and provide novel and efficient method for the practicalapplication in enhanced oil recovery.

Porous heterostructure of h-BN/carbon as an efficient electrocatalyst for hydrogen peroxide generation

Xu Xiang,Zhao Yuying,Yuan Qixin,Wu Yuhan,He Jiawei,Fan Mengmeng 한국탄소학회 2024 Carbon Letters Vol.34 No.6

We successfully synthesized a porous carbon material with abundant hexagonal boron nitride (h-BN) dispersed on a carbon matrix (p-BN-C) as efficient electrocatalysts for two-electron oxygen reduction reaction (2e− ORR) to produce hydrogen peroxide (H2O2). This catalyst was fabricated via ball-milling-assisted h-BN exfoliation and subsequent growth of carbon structure. In alkaline solutions, the h-BN/carbon heterostructure exhibited superior electrocatalytic activity for H2O2 generation measured by a rotating ring-disk electrode (RRDE), with a remarkable selectivity of up to 90–97% in the potential range of 0.3–0.6 V vs reversible hydrogen electrode (RHE), superior to most of the reported carbon-based electrocatalysts. Density functional theory (DFT) simulations indicated that the B atoms at the h-BN heterostructure interface were crucial active sites. These results underscore the remarkable catalytic activity of heterostructure and provide a novel approach for tailoring carbon-based catalysts, enhancing the selectivity and activity in the production of H2O2 through heterostructure engineering.

Electrochemical Behavior of a Vacuum-Brazed 10Ni-WC/NiCrBSi Composite Coating

Zhu Jiawei,Zou Jiasheng,Qiao Yanxin,Wang Yi,Xu Xiangping 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.11

In this work, a 10Ni-WC/NiCrBSi composite coating was fabricated on a Q235 substrate by using vacuum brazing. The bonding strength, surface hardness and corrosion behavior of the coating were characterized by using shearing, a Vickers hardness test and an electrochemical measurement. The results showed that the bonding strength was 365.1 MPa and that the surface hardness of the coating reached nearly 2500 HV, which was ten times that of the Q235 substrate. The corrosion trend of the coating was analyzed by electrochemical impedance spectroscopy and potentiodynamic polarization curves. The results showed that the electrochemical system of the coating was a charge-transfer control system with a passive behavior. Combined corrosion micro-morphology and the energy dispersive X-ray spectroscopy (EDS) showed that the 10Ni-WC/NiCrBSi composite coating had superior corrosion resistance, but the pitting corrosion resistance of the coating was poor. In addition, after corrosion, the hard phase particles inside the coating were shown not to fail. The corrosion resistance of the vacuum-cladded 10Ni-WC/NiCrBSi coating was obtained.

Bio-base Metal Organic Frameworks as Potential CO2 Adsorbents

Zhang Jiawei,Ma Jingjing,Liu Chen,Wang Qi,Xu Yiling,Fang Long,Xia Kai,Sun Deshuai 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.7

Environmental friendliness and high adsorption capacity are important properties of CO 2 adsorbents. Bio-based metal– organic framework (bioMOFs) materials off er notable benefi ts for CO 2 capture. Amino acids like L -glutamic acid (Glu) and L-aspartate (Asp) are employed as ligands for the synthesis of bioMOFs, Asp-Cu and Glu-Cu. Characterization results confi rmed that Asp-Cu and Glu-Cu possessed tertiary amine and secondary amine structures, respectively. The adsorption capacities of Glu-Cu and Asp-Cu were up to 253 mg·g −1 and 277 mg·g −1 at 1 bar CO 2 pressure and 190 mg·g −1 and 223 mg·g −1 at 0.15 bar CO 2 pressure. The CO 2 adsorption properties of bioMOFs were comprehensively evaluated under various conditions, including temperature, water content, SO 2 concentration, and other compositions. Adsorption data were fi tted well with the pseudo-fi rst-order kinetics and Weber-Morris intraparticle diff usion model. The kinetic studies revealed that a small amount of water signifi cantly accelerated the pseudo-fi rst-order kinetic constants, whereas excess water vapor greatly hindered the intra-diff usion constants of CO 2 . The presence of SO 2 led to a decrease in the adsorption capacity of both MOFs due to rapid reactions occurring with active sites on the MOF surface. Furthermore, these bioMOFs were easily recovered and regenerated for at least 20 cycles. The primary CO 2 adsorption mechanism involved catalytic hydration reactions on Asp-Cu, while chemical adsorption occurred on Glu-Cu. Both mechanisms were accompanied by physical adsorption.

Derivation of endothelial cells from porcine induced pluripotent stem cells by optimized single layer culture system

Renyue Wei,Jiawei Lv,Xuechun Li,Yan Li,Qianqian Xu,Junxue Jin,Yu Zhang,Zhonghua Liu 대한수의학회 2020 Journal of Veterinary Science Vol.21 No.1

Regenerative therapy holds great promise in the development of cures of some untreatable diseases such as cardiovascular diseases, and pluripotent stem cells (PSCs) including induced PSCs (iPSCs) are the most important regenerative seed cells. Recently, differentiation of human PSCs into functional tissues and cells in vitro has been widely reported. However, although porcine reports are rare they are quite essential, as the pig is an important animal model for the in vitro generation of human organs. In this study, we reprogramed porcine embryonic fibroblasts into porcine iPSCs (piPSCs), and differentiated them into cluster of differentiation 31 (CD31)-positive endothelial cells (ECs) (piPSC-derived ECs, piPS-ECs) using an optimized single-layer culture method. During differentiation, we observed that a combination of GSK3β inhibitor (CHIR99021) and bone morphogenetic protein 4 (BMP4) promoted mesodermal differentiation, resulting in higher proportions of CD31-positive cells than those from separate CHIR99021 or BMP4 treatment. Importantly, the piPS-ECs showed comparable morphological and functional properties to immortalized porcine aortic ECs, which are capable of taking up low-density lipoprotein and forming network structures on Matrigel. Our study, which is the first trial on a species other than human and mouse, has provided an optimized single-layer culture method for obtaining ECs from porcine PSCs. Our approach can be beneficial when evaluating autologous EC transplantation in pig models.