Particle size distributions and concentrations above radiators in indoor environments: Exploratory results from Xi`an, China

Xi Chen,Angui Li 대한환경공학회 2015 Environmental Engineering Research Vol.20 No.3

Particulate matter in indoor environments has caused public concerns in recent years. The objective of this research is to explore the influence of radiators on particle size distributions and concentrations. The particle size distributions as well as concentrations above radiators and in the adjacent indoor air are monitored in forty-two indoor environments in Xi’an, China. The temperatures, relative humidity and air velocities are also measured. The particle size distributions above radiators at ten locations are analyzed. The results show that the functional difference of indoor environments has little impact on the particle size distributions above radiators. Then the effects of the environmental parameters (particle concentrations in the adjacent indoor air, temperatures, relative humidities and air velocities) on particle concentrations above radiators are assessed by applying multiple linear regression analysis. Three multiple linear regression models are established to predict the concentrations of PM10, PM2.5 and PM1 above radiators.

Efficient VaR and CVaR Measurement via Stochastic Kriging

Chen, Xi,Kim, Kyoung-Kuk Institute for Operations Research and the Manageme 2016 INFORMS journal on computing Vol.28 No.4

<P>In this paper, stochastic kriging (SK) is considered as a metamodeling tool to capture risk-related properties of complex stochastic system outputs. To better assess the tail behavior of the underlying distribution of a system output, we specifically focus on global prediction of value-at-risk and conditional value-at-risk. Going beyond the standard SK framework intended for metamodeling of mean response surfaces, we rethink the original formulation to allow for the flexibility of utilizing different estimation methods for metamodel construction. The resulting impact on the predictive performance of SK is examined in detail. In parallel with the study by Chen et al. [Chen X, Ankenman BE, Nelson BL (2013) Enhancing stochastic kriging metamodels with gradient estimators. Oper. Res. 61(2): 512-528], we further consider the situation in which noisy gradient information can be incorporated into SK metamodel construction and prediction. The theoretical results are illustrated by two numerical examples.</P>

CircFam190a: a critical positive regulator of osteoclast differentiation via enhancement of the AKT1/HSP90β complex

Chen Kun,Chen Xi,Lang Chuandong,Yuan Xingshi,Huang Junming,Li Zhi,Xu Mingyou,Wu Kerong,Zhou Chenhe,Li Qidong,Zhu Chen,Liu Lianxin,Shang Xifu 생화학분자생물학회 2023 Experimental and molecular medicine Vol.55 No.-

The identification of key regulatory factors that control osteoclastogenesis is important. Accumulating evidence indicates that circular RNAs (circRNAs) are discrete functional entities. However, the complexities of circRNA expression as well as the extent of their regulatory functions during osteoclastogenesis have yet to be revealed. Here, based on circular RNA sequencing data, we identified a circular RNA, circFam190a, as a critical regulator of osteoclast differentiation and function. During osteoclastogenesis, circFam190a is significantly upregulated. In vitro, circFam190a enhanced osteoclast formation and function. In vivo, overexpression of circFam190a induced significant bone loss, while knockdown of circFam190a prevented pathological bone loss in an ovariectomized (OVX) mouse osteoporosis model. Mechanistically, our data suggest that circFam90a enhances the binding of AKT1 and HSP90β, promoting AKT1 stability. Altogether, our findings highlight the critical role of circFam190a as a positive regulator of osteoclastogenesis, and targeting circFam190a might be a promising therapeutic strategy for treating pathological bone loss.

The Top-K QoS-aware Paths Discovery for Source Routing in SDN

( Xi Chen ),( Junlei Wu ),( Tao Wu ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.6

Source routing is the routing scheme that arranges the whole path from source to target at the origin node that may suit the requirements from the upper layer applications’ perspective. The centralized control in SDN (Software-Defined Networking) networks enables the awareness of the global topology at the controller. Therefore, augmented source routing schemes can be designed to achieve various purposes. This paper proposes a source routing scheme that conducts the top-K QoS-aware paths discovery in SDN. First, the novel non-invasive QoS over LLDP scheme is designed to collect QoS information based on LLDP in a piggyback fashion. Then, variations of the KSP (K Shortest Paths) algorithm are derived to find the unconstrained/constrained top-K ranked paths with regard to individual/overall path costs, reflecting the Quality of Service. The experiment results show that the proposed scheme can efficiently collect the QoS information and find the top-K paths. Also, the performance of our scheme is applicable in QoS-sensitive application scenarios compared with previous works.

Reflections on Application of VR Technology in Field of News Media

Chen Xi,Jeanhun Chung 한국인터넷방송통신학회 2023 International Journal of Internet, Broadcasting an Vol.15 No.2

In recent years, virtual reality (VR) technology has been widely used in many industrial fields, especially in the fields of medical treatment, games, film and television, to improve the interaction between medical teaching and practical treatment. On the gaming side, the production of virtual reality gaming screens and scenes became increasingly popular, greatly expanding the form of the visual experience. But VR is no longer confined to the health care, education and entertainment industries. During this time, the news media industry has also begun to integrate virtual reality into interviews and user interactions. This study aims to analyze the development of VR technology from the perspectives of immersive VR news experience, real reporting, and prospects, and analyze and think about the interactive participation of media users, the transformation of traditional media, and the upgrading of practitioners' roles.

A FORWARD-BACKWARD VQ CLUSTERING ALGORITHM FOR MULTISYLLABLE WORD RECOGNITION

Xi Xian Chen,Chang Nian Cai 대한전자공학회 1989 JTC-CSCC : Joint Technical Conference on Circuits Vol.- No.-

Solid Texture Synthesis and Mapping of Liver for Virtual Surgery

Chen Si-Xi,Li Jian-Wei,Chen Guo-Dong 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.12

In order to see clearly the details inside the liver and enhance the users’ visual presence in the virtual surgery simulation system, the principles and methods of solid texture are used to render the photorealistic liver. Firstly, the sample sets are processed and multiple samples are used to synthesize the liver solid texture. Secondly, to improving the mapping efficiency of graphics hardware, the texture atlas is used to map the solid texture. In order to improve the fill rate of texture atlas, the height descending triangle bounding box method is used. The experimental result shows that the internal texture can be observed clearly. The study is of great significance to the photorealistic rendering of virtual liver surgery system, and provides a guideline for the solid texture synthesis and mapping of other human organs.

Enhancement of 1,3-Dihydroxyacetone Production from Gluconobacter oxydans by Combined Mutagenesis^s

( Xi Lin ),( Sha Liu ),( Guangrong Xie ),( Jing Chen ),( Penghua Li ),( Jianhua Chen ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.11

Wild strain L-6 was subjected to combined mutagenesis, including UV irradiation, atmospheric and room temperature plasma, and ion beam implantation, to increase the yield of 1,3-dihydroxyacetone (DHA). With application of a high-throughput screening method, mutant Gluconobacter oxydans I-2-239 with a DHA productivity of 103.5 g/l in flask-shake fermentation was finally obtained with the starting glycerol concentration of 120 g/l, which was 115.7% higher than the wild strain. The cultivation time also decreased from 54 h to 36 h. Compared with the wild strain, a dramatic increase in enzyme activity was observed for the mutant strain, although the increase in biomass was limited. DNA and amino acid sequence alignment revealed 11 nucleotide substitutions and 10 amino acid substitutions between the sldAB of strains L-6 and I-2-239. Simulation of the 3-D structure and prediction of active site residues and PQQ binding site residues suggested that these mutations were mainly related to PQQ binding, which was speculated to be favorable for the catalyzing capacity of glycerol dehydrogenase. RT-qPCR assay indicated that the transcription levels of sldA and sldB in the mutant strain were respectively 4.8-fold and 5.4-fold higher than that in the wild strain, suggesting another possible reason for the increased DHA productivity of the mutant strain.

Performance-based Analysis of Elastoplastic Rotational Behavior of Multi-cell Shaped Concrete-filled Steel Tubular Connection

Xi Chen,Jian-yang Xue,Hechao Li,Guangxu Tu,Xin Lu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.10

Experimental and theoretical research on the rotational behavior of Multi-cell shaped concrete-filled steel tubular (MCFST) connection under low-period cyclic load is performed. The experimental results showed that the design parameters had significant effects on the elastic rotational stiffness of the connection, and affected the sequence and position of the plastic hinges appearance at the column and beam ends. Furthermore, the damage mechanism of the plastic hinge lines is obtained, and the simultaneous yielding for the plastic hinges results in the rapid increase of the beam end rotation. In order to handle the problem with irregular geometry boundary and uneven distribution of tightening-ring stresses a differential element of an unified material is proposed considering the effective tightening-ring stresses of special-shaped steel tube on confined concrete, which can be used to analyse the whole mechanical and damage performance of the connection. Combining unified design theory and experimental results, the calculation for the elastic bending rigidity of the connection is obtained. Finally, the moment-rotation relation model of the connection is proposed by regression analysis on experimental results, and the theoretical results are observed to agree well with the experimental results.

The Causality Test of Network Technical Anonymity and Perceptive Anonymity

Xi Chen,Yujie Li 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.3

In order to discuss different types of network anonymity and the correlations among them, this paper separates network anonymity into two variables on the basis of subject object dichotomy. One is network technical anonymity, referring to the amount of information concealed that lead to difficulties in identifying the subject; the other is perceptive anonymity, which means how anonymous one perceive him/herself has been. Then the author explores how to measure these variables and set up a test model to see if there is any causal relation between them. The data was collected from Sina Weibo, and it is intended for empirical test. This thesis proved that there is an obvious causal relation between the two types of anonymity.