AUTOMATIC DETECTION AND EXTRACTION ALGORITHM OF INTER-GRANULAR BRIGHT POINTS

Feng, Song,Ji, Kai-Fan,Deng, Hui,Wang, Feng,Fu, Xiao-Dong The Korean Astronomical Society 2012 Journal of The Korean Astronomical Society Vol.45 No.6

Inter-granular Bright Points (igBPs) are small-scale objects in the Solar photosphere which can be seen within dark inter-granular lanes. We present a new algorithm to automatically detect and extract igBPs. Laplacian and Morphological Dilation (LMD) technique is employed by the algorithm. It involves three basic processing steps: (1) obtaining candidate "seed" regions by Laplacian; (2) determining the boundary and size of igBPs by morphological dilation; (3) discarding brighter granules by a probability criterion. For validating our algorithm, we used the observed samples of the Dutch Open Telescope (DOT), collected on April 12, 2007. They contain 180 high-resolution images, and each has a $85{\times}68\;arcsec^2$ field of view (FOV). Two important results are obtained: first, the identified rate of igBPs reaches 95% and is higher than previous results; second, the diameter distribution is $220{\pm}25km$, which is fully consistent with previously published data. We conclude that the presented algorithm can detect and extract igBPs automatically and effectively.

Generic Constructions for Strong Designated Verifier Signature

Feng, Deng-Guo,Xu, Jing,Chen, Wei-Dong Korea Information Processing Society 2011 Journal of information processing systems Vol.7 No.1

A designated verifier signature is a special type of digital signature, which convinces a designated verifier that she has signed a message in such a way that the designated verifier cannot transfer the signature to a third party. A strong designated verifier signature scheme enhances the privacy of the signer such that no one but the designated verifier can verify the signer's signatures. In this paper we present two generic frame works for constructing strong designated verifier signature schemes from any secure ring signature scheme and any deniable one-pass authenticated key exchange protocol, respectively. Compared with similar protocols, the instantiations of our construction achieve improved efficiency.

Generic Constructions for Strong Designated Verifier Signature

Deng-guo Feng,Jing Xu,Wei Dong Chen 한국정보처리학회 2011 Journal of information processing systems Vol.7 No.1

Urban governance in an increasingly mobile society: the case of Chinese cities

Feng Deng 서울시립대학교 도시과학연구원 2022 도시과학국제저널 Vol.26 No.4

Cities in transitional economies have experienced rising mobility and the simultaneous evolution of urban governance. This paper explores the relationship between both inter-city migration and intra-city residential mobility and urban governance, especially in the Chinese city, through theoretical reasoning and synthesizing previous works. While acknowledging that inter-city migration may force cities to improve urban governance through the agglomeration economy, I argue that, by weakening wage capitalization, inter-city migration strengthens property interests in urban governance, pushing it towards the progrowth model. The same mechanism applies to intra-city mobility. Besides, rising mobility weakens social control in the Chinese city, which faces a dilemma: grassroots governments are expected to strengthen social control after the decline of work unit, but they are gradually marginalized in private gated communities that are dominant in Chinese cities. The observed downward turn of residential mobility for local residents in the 2000s and continuously rising mobility for migrants are partly due to the homeownership effect and, as I emphasized in this paper, partly due to the protection for property owners from territorial organizations and urban governance at large.

Enhancing Student Beliefs about Mathematical Problem Solving: Effects of a Problem-Solving based Intervention

( Feng Deng ),( Eng Guan Tay ),( Tin Lam Toh ),( Yew Hoong Leong ),( Khiok Seng Quek ),( Pee Choon Toh ),( Jaguthsing Dindyal ),( Foo Him Ho ) 한국수학교육학회 2015 수학교육연구 Vol.19 No.1

Previous studies indicated that students tended to hold less satisfactory beliefs about the discipline of mathematics, beliefs about themselves as learners of mathematics, and beliefsabout mathematics teaching and learning. However, only a few studies had developed curricular interventions to change students`` beliefs. This study aimed to examine the effect of a problem-solving curriculum (i.e., Mathematical Problem Solving for Everyone, MProSE) on Singaporean Grade 7 students`` beliefs about mathematical problemsolving (MPS). Four classes (n =142) were engaged in ten lessons with each comprising four stages: understand the problem, devise a plan, carry out the plan, and look back. Heuristics and metacognitive control were emphasized during students`` problem solving activities. Results indicated that the MProSE curriculum enabled some students to develop more satisfactory beliefs about MPS. Further path analysis showed that students`` attitudes towards the MProSE curriculum are important predictors for their beliefs.

Analytical and Numerical Studies on Steel Columns with Novel Connections in Modular Construction

En-Feng Deng,Jia-Bao Yan,Yang Ding,Liang Zong,Zhong-Xian Li,Xiao-Meng Dai 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.4

modular construction is a new type of promising structures. This type of structure is an excellent alternative to conventional on-site buildings with advantages of shortened construction time, improved construction quality and reduced environmental pollution. A new concept of modular construction with novel connections has been proposed. This paper mainly focuses on the behavior and design of the innovative steel column working together with tenons at both ends. The fourthdifferential equation was firstly adopted to develop a theoretical model to determine the buckling length of the column. Then, a 3-D nonlinear finite element (FE) model was developed to simulate the ultimate strength behavior of the novel column under pure compression. Parametric studies reveal that the tenons play a significant role in affecting the ultimate load and the corresponding end shortening, among which the length of the tenons is the most important factor. The design approach and recommendations are also discussed through assessing the applicability of the current design code.

Numerical and analytical study on initial stiffness of corrugated steel plate shear walls in modular construction

En-Feng Deng,Liang Zong,Yang Ding 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.32 No.3

Modular construction has been increasingly used for mid-to-high rise buildings attributable to the high construction speed, improved quality and low environmental pollution. The individual and repetitive room-sized module unit is usually fully finished in the factory and installed on-site to constitute an integrated construction. However, there is a lack of design guidance on modular structures. This paper mainly focuses on the evaluation of the initial stiffness of corrugated steel plate shears walls (CSPSWs) in container-like modular construction. A finite element model was firstly developed and verified against the existing cyclic tests. The theoretical formulas predicting the initial stiffness of CSPSWs were then derived. The accuracy of the theoretical formulas was verified by the related numerical and test results. Furthermore, parametric analysis was conducted and the influence of the geometrical parameters on the initial stiffness of CSPSWs was discussed and evaluated in detail. The present study provides practical design formulas and recommendations for CSPSWs in modular construction, which are useful to broaden the application of modular construction in high-rise buildings and seismic area.

Analytical and Numerical Analysis on a New Type of Bolted Connection for Modular Steel Construction

En-Feng Deng,Jun-Yi Lian,Zhe Zhang,Zhe Liu,Ji-Jian Zhou,Shi-Quan Wang 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.4

Modular steel construction (MSC) has exhibited widespread applications in civil engineering. The inter-module connection is a key issue for the seismic performance of MSC. A detailed finite element model (FEM) of a new type of bolted connection was firstly developed. Its accuracy was validated by comparing numerical results with previous experimental results in terms of hysteretic curve and failure mode. A theoretical mechanical model was developed and its capabilities on predictions of initial rotational stiffness and ultimate moment resistance of the connection were checked through validations against test results. Further, a parametric study on several specimens with different axial load ratios, boundary conditions and section of the beams was conducted. The prediction capability of the theoretical model on seismic behavior of the connection with different beam sections was checked by comparing the skeleton curves of FEA results with theoretical ones. Subsequently, a simplified FEM was established and validated to accelerate the numerical simulation of the seismic performance of the connection.

Numerical Investigation and Design of Cold-formed Steel Angle Columns with Complex Edges under Axial Compression

Jun-Feng Zhang,Mengmeng Feng,En-Feng Deng,Shiyun Pang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.2

Currently, cold-formed steel (CFS) is widely used in fabricated steel structures for high strength-to-weight ratio and ease for installation. However, limited research is available in the literature on the CFS angle columns with complex edges under axial compression. In this paper, the axial compressive capacity of the CFS angle columns with complex edges was numerically studied. The distortional buckling characteristics of 1008 CFS angle sections with complex edges were analyzed by finite strip software CUFSM. Detailed non-linear finite element model (FEM) was developed based on finite element program ABAQUS and verified by comparing with test results. The verification indicated that the developed FEM could well predict the ultimate strength and failure model of the specimens. Using the validated FEM, an extensive parametric study comprised of 330 models was conducted. The influences of the specimen length, the edge ratio and the limb-width ratio of the angle section on the axial compressive capacity of CFS angle columns with complex edges were evaluated. Then an improved direct strength method (DSM) was proposed based on the existing DSM. The evaluations based on tests and FEA results showed that using the modified DSM to predict the load-bearing capacity of the CFS angle columns with complex edges was feasible.

Experimental Investigation on Energy Mechanism of Freezing-Thawing Treated Sandstone under Uniaxial Static Compression

Hongwei Deng,Songtao Yu,Junren Deng,Bo Ke,Feng Bin 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.5

To gain a further understanding of Freeze-Thaw weathering effect on the damage of sandstone from the perspective of energy analysis, uniaxial static compression tests were conducted on sandstone samples that suffered 0, 20, 60, 100 and 140 freezingthawing cycles. Then total input strain energy, releasable elastic strain energy, dissipated energy and freezing-thawing induced damage of samples under uniaxial static compression tests were calculated and analyzed. In the mean time, the energy absorption of sandstone under dynamic loading tests (SHPB (Split-Hopkinson pressure bar) experiments) were cited and made a contrast with the dissipated energy of samples under uniaxial static compression tests. The results show that the tangent modulus, total input strain energy, releasable elastic strain energy and dissipated energy of samples decrease with Freezing-Thawing cycles go on, while the freezing-thawing induced damage grow with freezing-thawing cycles increase. In term of energy used for destroying rock samples in different test modes, less energy is needed for destroying samples in uniaxial static compression tests and it decreases with F-T cycles increase, while more energy is needed for destroying samples in dynamic impact loading and it increases with F-T cycles increase. In addition, the number of fragments of broken sample increase with the F-T cycles both in uniaxial static compression tests and dynamic loading tests, and sample under dynamic loading tests is more broken than sample under uniaxial static compression tests.