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Search Results: 1 - 10 of 141214 matches for " Zhi Li "
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An Optimal Algorithm for Over-the-Air Reprogramming Protocol in WSNs  [PDF]
Ting WEN, Zhi LI
Communications and Network (CN) , 2009, DOI: 10.4236/cn.2009.12017
Abstract: The over-the-air reprogramming has played an important role in Wireless Sensor Networks (WSNs), and has been widely researched. But the problems of low efficiency and high energy consumption have brought new challenges to the research. This paper presents an optimal algorithm, it is targeted to address the problem of relatively low efficiency and high energy consumption in over-the-air reprogramming in WSNs. Simulation results demonstrate that the optimal algorithm can improve the efficiency of over-the-air reprogramming in WSNs, and make the energy consumption in network not only lower but more balanced.
An Energy-Efficient Access Control Algorithm with Cross-Layer Optimization in Wireless Sensor Networks  [PDF]
Zhi Chen, Shaoqian Li
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.22022
Abstract: This paper presents a wireless sensor network (WSN) access control algorithm designed to minimize WSN node energy consumption. Based on slotted ALOHA protocol, this algorithm incorporates the power control of physical layer, the transmitting probability of medium access control (MAC) layer, and the automatic repeat request (ARQ) of link layer. In this algorithm, a cross-layer optimization is preformed to minimizing the energy consuming per bit. Through theory deducing, the transmitting probability and transmitting power level is determined, and the relationship between energy consuming per bit and throughput per node is provided. Analytical results show that the cross-layer algorithm results in a significant energy savings relative to layered design subject to the same throughput per node, and the energy saving is extraordinary in the low throughput region.
Emergency Tasks Planning Based on Formal Modeling of Emergency Plan and HTN Planning System SHOP2  [PDF]
Jun Tian, Zhi Li
Intelligent Information Management (IIM) , 2012, DOI: 10.4236/iim.2012.46040
Abstract: A theoretical approach of ordered emergency tasks generation is proposed for dealing with a specific emergency event rapidly, exactly and effectively. According to the general principles of an emergency plan developed to response to an emergency management, a workflow model is employed to complete the formal modeling of concrete emergency plan firstly. Then the HTN planning system SHOP2 is introduced, the transformation method of domain knowledge from emergency domain to SHOP2 domain is studied. At last, the general procedure to solve the emergency decision prob-lems and to generate executive emergency tasks is set up drawing support from SHOP2 planning system, which will combine the principles (or knowledge) of emergency plan and the real emergency situations.
Towards Quantitative Characterisation of the Small Force Transducer Used in Nanoindentation Instruments  [PDF]
Zhi Li, Uwe Brand
Modern Instrumentation (MI) , 2013, DOI: 10.4236/mi.2013.24009

Quantitative characterization of the mechanical properties of materials in micro-/nano-scale using depth-sensing indentation technique demands high performance of nanoindentation instruments in use. In this paper, the efforts to calibrate the capacitive force transducer of a commercial nanoindentation instrument are presented, where the quasi-static characteristic of the force transducer has been calibrated by a precise compensation balance with a resolution of ~1 nN. To investigate the dynamic response of the transducer, an electrostatic MEMS (Micro-Electro-Mechanical System) based on nano-force transfer standard with nano-Newton (10-9 Newton) resolution and a bandwidth up to 6 kHz have been employed. Preliminary experimental results indicate that 1) the force transducer under calibration has a probing force uncertainty less than 300 nN (1σ) in the calibration range of 1 mN; 2) the transient duration at contact points amounts to 10 seconds; 3) the overshoot of engagement is pre-load dependent.

Study on the Outward FDI in the USA of Chinese Enterprises  [PDF]
Shuangqin Liu, Zhi Li
Open Journal of Social Sciences (JSS) , 2015, DOI: 10.4236/jss.2015.37006

With the rapid economic development, China has sufficient foreign exchange reserves. Together with the appreciation in Chinese currency and other conditions, more and more Chinese enterprises invest overseas especially in the USA. Based on the statistics of the National Bureau of Statistics of the People’s Republic of China, in 2012 and 2013, among the top 3 countries in which Chinese enterprises have invested, the?USA ranked the second with US$ 4047.85 million and the third with US$ 3873.43 million respectively. Chinese enterprises’ FDI in the USA has been mutually beneficial to both China and the USA. However, Chinese enterprises’ FDI in the USA has encountered a variety of obstacles from the USA including American government’s interfering with FDI by political methods, difficulty to enter into some industries, and America’s protectionism. On the other hand, those Chinese enterprises also have some problems in their outward FDI in the USA such as unstable development trend of FDI, enterprises of small size with the privately-owned enterprises as the main body, and unfamiliarity with the related policies and laws. What countermeasures should Chinese enterprises adopt to deal with the obstacles or problems? This paper aims at analyzing the obstacles from the USA and the problems existing in those Chinese enterprises’ FDI in the USA by means of SWOT method and puts forward some corresponding countermeasures for the Chinese enterprises to conduct their outward FDI in the USA more effectively. The conclusions can be used for reference by companies which plan to invest in the USA or other foreign countries.

Social Responsibilities and Evaluation Indicators of Listed Companies in the Perspective of Interest Groups  [PDF]
Shuhua Liu, Li Cai, Zhi Li
American Journal of Industrial and Business Management (AJIBM) , 2012, DOI: 10.4236/ajibm.2012.23014
Abstract: With advocating scientific outlook on development and building a harmonious society, China has paid more and more attention to corporate social responsibilities, which mean that companies should fulfill their duties for the interest groups, such as shareholders, employees, consumers, suppliers, communities and governments. As China’s major economic entities, listed companies are supposed to be the pioneers who undertake on social responsibilities. From the standpoints of interest groups, it is necessary to define and determine the social responsibilities of listed companies, build an evaluation indicator system for their responsibilities, turn their responsibilities from the invisible into the visible and explore evaluation modes as well as scientific methods to evaluate their performance, so as to guide them to perform their social responsibilities properly.
4,4′-[p-Phenylenebis(oxy)]dibutanoic acid
Zhi Li
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811036828
Abstract: The complete molecule of the title compound, C14H18O6, has a center of inversion at the centroid of the benzene ring and the asymmetric unit contains one half-molecule. The conformation of the side chain is anti [C—C—C—C = 171.40 (17)°]. In the crystal, pairs of head-to-head carboxylic acid O—H...O hydrogen bonds link the molecules into infinite zigzag chains propagating along [130]. Weak C—H...π interactions between adjacent chains expand the structure into a layered network in the ac plane.
3-Oxapentane-1,5-diyl dicarbamate
Zhi Li
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812011981
Abstract: The complete molecule of the title compound, C6H12N2O5, is generated by a rotation about a twofold axis. The conformation along the bond sequence linking the two amino groups is trans-trans-(+)gauche-trans-trans. In the crystal, N—H...O hydrogen bonds link the molecules into a three-dimensional supramolecular architecture.
1,4-Phenylenebis(methylene) dicarbamate
Zhi Li
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812012718
Abstract: The title compound, C10H12N2O4, is a phenyl dicarbamate with crystallographically imposed inversion symmetry. The dihedral angle between the carbamoyloxy plane [i.e. the plane of the N—C(O)—O fragment; r.m.s. deviation = 0.002 (3) ] and the plane of the aryl ring is 29.2 (1)°. In the crystal, two different centrosymmetric N—H...O hydrogen-bond interactions are observed; these are described as R22(8) and R24(8) in graph-set notation. The rings form an alternating sequence, linking the molecules into a sheet structure parallel to (011).
Remarkable pitfalls in the diagnosis of primary central nervous system lymphoma
LI Zhi
Chinese Journal of Contemporary Neurology and Neurosurgery , 2013, DOI: 10.3969/j.issn.1672-6731.2013.01.003
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