Improved definition of dynamic load allowance factor for highway bridges

Yongjun Zhou,Zhongguo John Ma,Yu Zhao,Xiongwei Shi,Shuanhai He 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.54 No.3

The main objective of this paper is to study the dynamic load allowance (DLA) calculationmethods for bridges according to the dynamic response curve. A simply-supported concrete bridge with asmooth road surface was taken as an example. A half-vehicle model was employed to calculate the dynamicresponse of deflection and bending moment in the mid-span section under different vehicle speeds using thevehicle-bridge coupling method. Firstly, DLAs from the conventional methods and code provisions wereanalyzed and critically evaluated. Then, two improved computing approaches for DLA were proposed. Inthe first approach, the maximum dynamic response and its corresponding static response or itscorresponding minimum response were selected to calculate DLA. The second approach utilized weightedaverage method to take account of multi-local DLAs. Finally, the DLAs from two approaches werecompared with those from other methods. The results show that DLAs obtained from the proposedapproaches are greater than those from the conventional methods, which indicate that the currentconventional methods underestimate the dynamic response of the structure. The authors recommend that theweighted average method based on experiments be used to compute DLAs because it can reflect thevehicle’s whole impact on the bridge.

SERS study of Ag/FeS/4-MBA interface based on the SPR effect

Ma, Ning,Zhang, Xin-Yuan,Fan, Wenyue,Guo, Shuang,Zhang, Yongjun,Liu, Yang,Chen, Lei,Jung, Young Mee Elsevier 2019 Spectrochimica acta. Part A, Molecular and biomole Vol.219 No.-

<P><B>Abstract</B></P> <P>In this work, an ordered metal-semiconductor molecular system was introduced, and 4-mercaptobenzoic acid (4-MBA) was employed to study the charge transfer (CT) at the metal-semiconductor interface based on surface-enhanced Raman scattering (SERS) spectra. The thickness of the sputtered FeS was controlled so that the surface plasmon resonance (SPR) of Ag underwent a displacement change, and the contribution of the SPR to the CT was studied through surface plasmon (SP) absorption. Furthermore, SERS spectra obtained at different excitation wavelengths were used to calculate the degree of CT in the layer-by-layer sputtering system. When Ag was irradiated with incident light, the strong SPR of Ag was excited, generating an increased electromagnetic field (EM). This amplified EM generated hot electrons at the interface between the FeS and Ag, and then the hot electrons were rearranged. Therefore, we established a simple and effective method for studying the impact of SPR on interfacial CT and analyzed the SERS spectra in accordance with Lombardi's basic theory and the physical effects associated with SPR. This theory is in good agreement with the experimental results. On this basis, we also proposed a mechanism by which SPR impacts the CT, which is beneficial for studying interfacial CT and obtaining an in-depth understanding of the CT mechanism in SERS. This work also enables the expansion of the applications of the SERS technique in the field of nanomaterials.</P> <P><B>Highlights</B></P> <P> <UL> <LI> SERS substrate was designed based on the layer-by-layer sputtering of Ag/FeS. </LI> <LI> 4-MBA was employed to study the CT at the metal-semiconductor interface. </LI> <LI> The SPR of Ag promotes the electron transfer process of the Ag/FeS/4-MBA system. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>In this paper, we designed a layer-by-layer sputtering of Ag and FeS on the PS template. FeS, as an ultranarrow bandgap semiconductor with a bandgap width of only 0.1 eV, exhibited different properties for SERS. The SPR of Ag can be tuned by controlling the FeS film thickness, which is beneficial for studying interface CT and obtaining an in-depth understanding of the CT mechanism in SERS.</P> <P>[DISPLAY OMISSION]</P>

Improved definition of dynamic load allowance factor for highway bridges

Zhou, Yongjun,Ma, Zhongguo John,Zhao, Yu,Shi, Xiongwei,He, Shuanhai Techno-Press 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.54 No.3

The main objective of this paper is to study the dynamic load allowance (DLA) calculation methods for bridges according to the dynamic response curve. A simply-supported concrete bridge with a smooth road surface was taken as an example. A half-vehicle model was employed to calculate the dynamic response of deflection and bending moment in the mid-span section under different vehicle speeds using the vehicle-bridge coupling method. Firstly, DLAs from the conventional methods and code provisions were analyzed and critically evaluated. Then, two improved computing approaches for DLA were proposed. In the first approach, the maximum dynamic response and its corresponding static response or its corresponding minimum response were selected to calculate DLA. The second approach utilized weighted average method to take account of multi-local DLAs. Finally, the DLAs from two approaches were compared with those from other methods. The results show that DLAs obtained from the proposed approaches are greater than those from the conventional methods, which indicate that the current conventional methods underestimate the dynamic response of the structure. The authors recommend that the weighted average method based on experiments be used to compute DLAs because it can reflect the vehicle's whole impact on the bridge.

자기소개서 분석을 통한 지원자의 두뇌 우성 분류

이용준(Yongjun Lee),권주원(Juwon Kwon),김중원(Jungwon Kim),마지우(Jiou Ma),이인혁(Inhyeok Lee),김동규(Dongkyu Kim),강태원(Taewon Kang) 한국정보기술학회 2021 Proceedings of KIIT Conference Vol.2021 No.11

본 논문에서는 로지스틱 회귀 분류기를 이용한 지원자의 두뇌 우성 분류에 관해 연구한다. 헤르만 사분면 (Herrmann Quadrants)에 따라 자기소개서를 사분면 각각의 특성에 맞춰 구분한 뒤, 각 자기소개서가 포함하는 특정 단어의 빈도와 비율을 계산하여 분류기를 학습시킨다. 학습된 분류기를 이용해 자기소개서를 작성한 지원자의 성향을 판단하고, 이를 통해 기업에서는 본인들이 원하는 성향을 지닌 지원자를 쉽게 찾음으로써, 채용비용을 절감할 수 있는 방향을 제시한다. In this paper, we study the judgement of applicant’s disposition using a Logistic Regression. We classify cover letter according to the characteristics of each of the ‘Herrmann Quadrants’, then, we calculate the frequency and proportion of specific words each of which contains, and train the classifier with this. We can judgement of applicant"s disposition using this classifier. And through this result, the enterprise can find applicant easily who have better disposition that they wants. And finally, this suggests a way to reduce hiring costs.

상호작용 중심의 사용자 학습 홈케어 Ai 로봇, MIMIC-U

유용준(Yongjun Yu),마지현(Jihyeon Ma),안보근(Bogeun An),강민지(Minji Kang),박기철(Kichul Park) 한국디자인학회 2023 한국디자인학회 학술발표대회 논문집 Vol.2023 No.10

A New Fine-grain SMS Corpus and Its Corresponding Classifier Using Probabilistic Topic Model

( Jialin Ma ),( Yongjun Zhang ),( Zhijian Wang ),( Bolun Chen ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.2

Nowadays, SMS spam has been overflowing in many countries. In fact, the standards of filtering SMS spam are different from country to country. However, the current technologies and researches about SMS spam filtering all focus on dividing SMS message into two classes: legitimate and illegitimate. It does not conform to the actual situation and need. Furthermore, they are facing several difficulties, such as: (1) High quality and large-scale SMS spam corpus is very scarce, fine categorized SMS spam corpus is even none at all. This seriously handicaps the researchers’ studies. (2) The limited length of SMS messages lead to lack of enough features. These factors seriously degrade the performance of the traditional classifiers (such as SVM, K-NN, and Bayes). In this paper, we present a new fine categorized SMS spam corpus which is unique and the largest one as far as we know. In addition, we propose a classifier, which is based on the probability topic model. The classifier can alleviate feature sparse problem in the task of SMS spam filtering. Moreover, we compare the approach with three typical classifiers on the new SMS spam corpus. The experimental results show that the proposed approach is more effective for the task of SMS spam filtering.

Network Threat Behavior Detection and Trend Analysis Based on the TDLC Model

Dong Ma,Yongjun Wang 한국산학기술학회 2013 SmartCR Vol.3 No.4

The rapid development of computer networks has accelerated the development of society, but also leads to much more frequent network attacks, and makes the attacks much more complex. Therefore, network intrusion detection becomes a great challenge to security in both industry and academics. In this paper, we present a network detection method based on a collaborative model against network threats and attacks, as well as trend analysis of network structure. First of all, the threat detection level collaboration model is given a specific framework and build process, as well as collaborative mechanisms. We then provide a pattern-matching algorithm and a behavioral sequence template for a simple introduction to this approach, and we explain how to use the collaborative model structure. Finally, the security situation of the entire network is analyzed by a quantitative situation evaluation model, cooperating with the network topology, and the threat type is determined by a D-S evidence theory algorithm. The experiment results show that, while running in an intranet security guard system of a large enterprise, a next-step attack can be predicted by our algorithm, and the security situation of the entire network can be accurately evaluated as well.

Experiment on the Behavior of a Self-Anchored Suspension and Cable-Stayed Hybrid Bridge during Structural Transformation

Yu Zhao,Yongjun Zhou,Lingling Wu,Changchang Li,Zhongguo John Ma 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.6

The Longgang Bridge in Shaanxi, China, is a complex continuous hybrid structure composed of two cable-stayed self-anchored suspension parts and one single-pylon cable-stayed part. A 1:20-scaled model was established due to the effect of multiple structural transformation, frequent internal force changes during the construction process, and differences between actual material parameters and theoretical calculation parameters. In this paper, the design, materials, counterweight, experimental instrumentation, and construction stages of the scaled model are introduced. Based on the experimental data, the nonlinear behavior of the self-anchored suspension and cable-stayed hybrid bridge during the structural transformation of the construction process is systematically and comprehensively studied. The evolutions of the hanger force and stayed cable force, the variation in the subcable and back-cable forces, the displacement characteristics of the suspension cable and the deflection of the stiffened girder are analyzed, and the relationships among these variables in different states of the structural system are discussed. This paper will serve as a technical reference for the construction of similar bridges in the future.

Self-Organized Synthesis and Mechanism of SnO2@Carbon Tube-Core Nanowire

Minting Luo,Yongjun Ma,Chonghua Pei,Yujing Xing,Lixia Wen,Li Zhang 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.8

SnO2@carbon tube-core nanowire was synthesized via a facile self-organized method, which was in situ by one step via Chemical Vapor Deposition. The resulting composite was characterized by scanning electron microscopy, X-ray diffraction and transmission electron microscope. The diameter of the single nanowire is between 5 nm and 60 nm, while the length would be several tens to hundreds of micrometers. Then X-ray diffraction pattern shows that the composition is amorphous carbon and tin dioxide. Transmission electron microscope images indicate that the nanowire consists of two parts, the outer carbon tube and the inner tin dioxide core. Meanwhile, the possible growth mechanism of SnO2@carbon tube-core nanowire is also discussed.

Insensitive High Cyclotrimethylenetrinitramine (RDX) Nanostructured Explosives Derived from Solvent/Nonsolvent Method in a Bacterial Cellulose (BC) Gelatin Matrix

Qingping Luo,Chonghua Pei,Guixiang Liu,Yongjun Ma,Zhaoqian Li 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2015 NANO Vol.10 No.3

Cyclotrimethylenetrinitramine (RDX) is an energetic material (EM) from the class of cyclic nitroamine explosive widely used in military applications because of its excellent integral properties. Using bacterial cellulose (BC) gelatin with a three-dimensional network as a matrix, N,Ndimethyllformamide (DMF) as the solvent of RDX, the RDX nanostructured explosives were prepared through the solvent/nonsolvent method. It was found that the solvent had a great impact on the crystallization of RDX in the solution and the RDX content in the nanostructured explosive. The RDX particles in the nanostructured explosives smoothly coated to the nanofibers of BC gelatin network at high RDX concentrations, and the granularity distributions of RDX in the nanostructured explosives were very uniform in the range of 30–50 nm. The average contents of the RDX in the nanostructured explosives are greater than 83 wt.% when the RDX concentrations of the soaked solutions are greater than 0.20 g/mL. The average content is approximately 91 wt.% when the RDX concentration is 0.30 g/mL. The decomposition temperatures of the RDX nanostructured explosives were found to decrease approximately to 20 C and their mechanical sensitivities decreased greatly compared to that of raw micro-size RDX. It opens a useful way to prepare nanostructured explosives with high energy and low mechanical sensitivity.