OALib Journal期刊

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匹配条件: “LI Jiao” ,找到相关结果约121844条。
Fast Tracks: A Comparison of High Speed Rail in China, Europe and the United States  [PDF]
Junfeng Jiao, Jenna Harbin, Yuan Li
Journal of Transportation Technologies (JTTs) , 2013, DOI: 10.4236/jtts.2013.32A007

High speed rail systems have blossomed in technological advances since their debut in the 1960’s with the Japanese Shinkansen line. As miles upon miles of tracks increase around the world, bringing added mobility to travelers while decreasing emissions, various technologies are leading the way to a faster tomorrow. This article explores the differences in what countries around the world are using to supply the next generation of travel modes. This paper details the differences in technological implementations from Asia, Europe, and North America. High speed rail systems are far more developed in other countries, especially China, and have required substantial government investment. The United States, with limited HSR development, stands to benefit from the technological advances of others and learn from the economic impacts of HSR in other countries.

A Fast Extraction Method in the Applicaton of UHV Transmission Line Fault Location  [PDF]
Li Wang, Jiale Suonan, Zaibin Jiao
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B242

To aim at the distribution parameter characteristics of UHV transmission line, this paper presents a fast extraction method (FE) to extract the accurate fundamentals of current and voltage from the UHV transmission line transient process, and locates the fault by utilizing two-end unsynchronized algorithm. The simulation result shows that this method has good performance of accuracy and stability, and has better location precision by comparing with results of one cycle Fourier algorithm. Therefore the method can efficiently improve the precision of fault location during the transient process, and makes the error of location results less than 0.5%.

Automatic identification and normalization of dosage forms in drug monographs
Jiao Li, Zhiyong Lu
BMC Medical Informatics and Decision Making , 2012, DOI: 10.1186/1472-6947-12-9
Abstract: As a step toward providing users with integrated access to multiple trustworthy drug resources, we aim to develop a method capable of identifying drug's dosage form information in addition to drug name recognition. We developed rules and patterns for identifying dosage forms from different sections of full-text drug monographs, and subsequently normalized them to standardized RxNorm dosage forms.Our method represents a significant improvement compared with a baseline lookup approach, achieving overall macro-averaged Precision of 80%, Recall of 98%, and F-Measure of 85%.We successfully developed an automatic approach for drug dosage form identification, which is critical for building links between different drug-related resources.Seeking drug-related information is one of the major activities of today's online healthcare professionals and consumers. To date, there are a wide variety of different drug-related resources including but not limited to: the biomedical literature in PubMed? [1], clinical trials in ClinicalTrial.gov [2], adverse drug effects in FDA's Spontaneous Reporting System, and consumer-level drug monographs in MedlinePlus? [3] and PubMed Health [4]. Owing to the heterogeneous nature of each individual resource, they are not currently linked to each other. On the other hand, their contents are often complementary to each other so that users would benefit from an integrated access to all sources relevant to a single drug. Thus, this poses an increasing need to build cross-links between these different resources for the same drug entity so that users from one site can be informed by relevant information in other sites. To this end, a critical step is to be able to identify the drug entity from the corresponding narrative text.Biomedical named entity recognition (NER) is a challenging task but it serves as a prerequisite for many subsequent tasks like relationship extraction [5]. Over the years, most NER tools have been developed for automatically recogni
Tris(nitrato-κ2O,O′)bis[4,4,5,5-tetramethyl-2-(pyridin-2-yl-κN)imidazoline-1-oxyl 3-oxide-κO]holmium(III)
Dong-Jiao Li
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812012445
Abstract: In the title compound, [Ho(NO3)3(C12H16N3O2)2], the HoIII ion is ten-coordinated in a distorted bicapped square-antiprismatic environment by two N,O-bidentate nitronyl nitroxide radical ligands and three O,O′-bidentate nitrate anions. Complex molecules are connected by C—H...O hydrogen bonds into a three-dimensional network.
Anomalous heat conduction and anomalous diffusion in one dimensional systems
Baowen Li,Jiao Wang
Physics , 2003, DOI: 10.1103/PhysRevLett.91.044301
Abstract: We establish a connection between anomalous heat conduction and anomalous diffusion in one dimensional systems. It is shown that if the mean square of the displacement of the particle is $<\Delta x^2> =2Dt^{\alpha} (0<\alpha\le 2)$, then the thermal conductivity can be expressed in terms of the system size $L$ as $\kappa = cL^{\beta}$ with $\beta=2-2/\alpha$. This result predicts that a normal diffusion ($\alpha =1$) implies a normal heat conduction obeying the Fourier law ($\beta=0$), a superdiffusion ($\alpha>1$) implies an anomalous heat conduction with a divergent thermal conductivity ($\beta>0$), and more interestingly, a subdiffusion ($\alpha <1$) implies an anomalous heat conduction with a convergent thermal conductivity ($\beta<0$), consequently, the system is a thermal insulator in the thermodynamic limit. Existing numerical data support our results.
Monitoring Mental Fatigue in Analog Space Environment Using Optical Brain Imaging  [PDF]
Xuejun Jiao, Jing Bai, Shanguang Chen, Qijie Li
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.55B011
Abstract: Accurate assessment of mental fatigue level would improve operational safety and efficacy of astronauts for long-term space flight. Identification of neurophysiological markers can index impending overload or fatigue before performance decrements using neuroimaging technologies. The current study utilized functional near-infrared spectroscopy (fNIR) to investigate the relationship of hemodynamic response in prefrontal cortex with changes of mental fatigue level, task performance (reaction time) during n-back working memory task and routine work task in analog space environment. Results indicated that the information entropy of hemodynamic response is related to task performance and subjective self-reported measures; the reaction time is predicted by regression analysis; and the accuracy of mental fatigue classification approaches 90%. Since fNIR is a portable, wearable and minimally intrusive methodology, it has the potential to be deployed in future space environments to monitoring mental fatigue and assessing the effort of operators in field environments.
OFDM Wireless Downhole Transmission Systems and Proposed SLM Method for PAPR Reduction  [PDF]
Renze Luo, Yupu Dang, Rui Li, Jiao Yang
Communications and Network (CN) , 2014, DOI: 10.4236/cn.2014.61002

At present, mud pulse transmission systems are widely used in downhole data transmission. But the systems are very low in transmission efficiency, only 5-10 bits/s, with very large anti-inter-symbol-interference (ISI). It cannot meet high requirements for high-speed transmission of modern logging system. The development of communication technology has laid some foundation for this requirement. For this purpose, the Orthogonal Frequency Division Multiplexing (OFDM) Wireless Downhole Transmission Systems are proposed for the first time because of their high transmission rate, anti-inter-symbol-interference (ISI), and high spectral efficiency, etc. Due to non-linear power amplifier (PA) of logging systems with limited dynamic range, the drawbacks of high peak-average power ratio (PAPR) may outweigh all the potential benefits of OFDM wireless downhole transmission systems. Selective mapping (SLM) method can reduce the PAPR of OFDM logging signals without distortion. But at the receiver, the conventional SLM method needs exact bits of side information (SI) to recover the data signal. The probability of erroneous SI detection has a significant influence on the error performance of the system. And individual transmissions of SI result in the reduction of bandwidth efficiency. To restore the exact data signal, our scheme codes the SI bits by linear block codes (LBC), and is easily decoded by syndrome decoding. And then the coding SI bits are superimposed onto the logging signals to omit SI bits transmission. The theory and simulation results show that the proposed method has better performance than the conventional one. Accordingly, the OFDM wireless downhole transmission systems can tackle the high PAPR problem, and highten the transmission rate of logging signals.

Hongzhi Jiao,Frank Y. Li
International Journal of Computer Networks & Communications , 2011,
Abstract: This paper proposes a TDMA-based medium access control protocol which enables cooperative communications in multi-hop wireless mesh networks. According to the proposed scheme, each router at the two-hop neighbourhood of each other is allocated to a specific time slot for accommodating either direct or cooperative transmissions in a coordinated manner, controlled by mini-slots which are part of the time slot. Benefiting from the elaborate mini-slot design, channel resources are fairly and efficiently allocated to each router so that no handshake is needed prior to each packet transmission. By providing access priority to cooperative transmission through an optimal relay which is determined by combined instantaneous relay channel conditions, higher system throughput can be achieved. To analyze the performance of the proposed cooperative protocol a Markov chain is introduced to model the behavior ofthe protocol. Simulation results demonstrate that the proposed MAC scheme can improve not only the one-hop transmission throughput but also the end-to-end throughput significantly. Moreover, the throughput performance of the proposed scheme is robust as packet size varies.
A Dynamic Parallel-rendezvous MAC Mechanism in Multi-rate Cognitive Radio Networks: MechanismDesign and Performance Evaluation
Lei Jiao,Frank Y. Li
Journal of Communications , 2009, DOI: 10.4304/jcm.4.10.752-765
Abstract: Parallel rendezvous multi-channel MAC mechanisms are regarded as an efficient method for media access control in cognitive radio networks since they do not need a control channel and use only one transceiver. However, existing parallel rendezvous MAC mechanisms assume that all channels have the same maximum capacity and channel availability for secondary users. In this paper, we propose a dynamic parallel rendezvous multi-channel MAC mechanism for synchronized multi-rate cognitive radio networks in which secondary users jump among different channels according to their own distinct hopping sequences and a node can adjust its hopping sequence according to channel conditions, in order to achieve higher system capacity. A Markov chain based model is designed to analyze the system capacity of the proposed mechanism. Numerical results show that the new mechanism can significantly improve system capacity of cognitive radio networks, compared with the traditional channel hopping MAC mechanisms.
An S-type eigenvalue localization set for tensors
Chaoqian Li,Aiquan Jiao,Yaotang Li
Mathematics , 2015,
Abstract: An S-type eigenvalue localization set for a tensor is given by breaking N={1,2,...,n} into disjoint subsets S and its complement. It is shown that the new set is tighter than those provided by L. Qi (Journal of Symbolic Computation 40 (2005) 1302-1324) and Li et al. (Numer. Linear Algebra Appl. 21 (2014) 39-50). As applications of the results, a checkable sufficient condition for the positive definiteness of tensors and a checkable sufficient condition of the positive semi-definiteness of tensors are given.

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