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Search Results: 1 - 10 of 130251 matches for " LI Ang "
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2,7-Dimethyl-2,7-diazoniapyrene bis(hexafluorophosphate)
Li Ang
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811001978
Abstract: In the title compound, C16H14N22+·2PF6 , the 2,7-dimethyl-2,7-diazapyrenium (DM-diaz) cation lies on a crystallographic twofold rotation axes. The diaz groups are nearly coplanar, with a maximum deviation of 0.008 (3) . In the crystal, molecules are linked into a two-dimensional lamellar framework parallel to (104) through weak C—H...F interactions.
Research and Design of an Airfield Runway FOD Detection System Based on WSN
Li Ang
International Journal of Distributed Sensor Networks , 2013, DOI: 10.1155/2013/839586
Abstract: Foreign object debris (FOD) would potentially cause huge damage when it appears on the airport runway, so the FOD surveillance system is one of the essential protectors for airplane’s safety now. This paper introduces a designed method of airport runway FOD detection system based on WSN, analyzes function of various image acquisition sensors, and introduces FOD image analysis algorithm. Finally WSN data fusion technology is used to analyze the FOD image. 1. Foreword What is FOD? FOD is the abbreviation of foreign object debris, which refers to a foreign substance that may damage the aircraft system. There are many types of FOD, such as connecting pieces between aircraft and engine, flying objects, wild animal, leaves, sand, and stone. FOD is very harmful to the aircraft. For example, Air France Concorde crash in July 25, 2000 caused by FOD killed 113 people. The crash created by FOD took research of FOD automatic, fast, and accurate monitoring and alarm system on the agenda. This further proved that an effective safety airport runway intelligent detection system is an important part of the airport flight safety system. Nowadays, there are four typical systems in the world, the British Tarsier system (Figure 1(a)), FOD Detect detection system of Israel (Figure 1(b)), FOD Finder monitoring system (Figure 1(c)), and iFerret monitoring system (Figure 1(d)) [1–4]. Figure 1: (a) Tarsier system. (b) FOD Detect detection system. (c) FOD Finder monitoring system. (d) iFerret monitoring system. At present, most of the domestic airports are still using manual method which is neither efficient nor safe. China has not yet found the radar system on FOD monitoring. Current research methods for detecting runway FOD are mainly for image processing on the runway image to realize the detection and localization of FOD. This paper introduces the design of a runway detection system based on WSN. The main purpose of this design is to conduct real-time detection, recognition, and tracking of track target, for the general sensors are unable to achieve this goal. In this design, the radar sensor, visible light cameras, infrared cameras, and laser ranging technology are used to further analyze the grade of target threat and the position of the FOD. In addition, the system uses multiple sensors to detect, so we use the sensor data fusion technology. This design is both innovative and practical. 2. Construction of System Model 2.1. The Basic Function of the System According to the needs of real-time detection of airport runway FOD, FOD detection system should have the following
Residential Community Open-Up Strategy Based on Prim’s Algorithm and Neural Network Algorithm  [PDF]
Ximing Lv, Ang Li, Shunkai Zhang, Jianbao Li
Journal of Applied Mathematics and Physics (JAMP) , 2017, DOI: 10.4236/jamp.2017.52047
Abstract: “Open community” has aroused widespread concern and research. This paper focuses on the system analysis research of the problem that based on statistics including the regression equation fitting function and mathematical theory, combined with the actual effect of camera measurement method, Prim’s algorithm and neural network to “Open community” and the applicable conditions. Research results show that with the increasing number of roads within the district, the benefit time gradually increased, but each type of district capacity is different.
Research on Smart Growth of Sustainable Cities Based on Information Entropy and Super-Efficiency DEA Model  [PDF]
Ximing Lv, Shunkai Zhang, Ang Li, Jianbao Li
Journal of Applied Mathematics and Physics (JAMP) , 2017, DOI: 10.4236/jamp.2017.55103
Abstract: Since the “smart growth” was put forward in the late 90s, it has become an accepted design idea and concept in the field of urban design in the world, and has been deeply studied and applied. In order to better promote “smart grown”, we set up an evaluation system, which consists of eleven indicators. In this paper, Oxford City and Fengzhen City are used as the objects of the study. Then smart growth evaluation model is established. The weight of the index is calculated by the entropy method. We use the model to evaluate the development plans of the two cities, from which to calculate the contribution of the indicators on the level of smart growth. Finally, we use the super-efficient data envelopment analysis model (DEA) to rank the importance of the indicators to the smart growth. The results show that the level of smart growth in Oxford is higher than that in Fengzhen. And “Multifunctional Building Density in Central City”, “The Density of Public Area in Central City” two indicators account for more than 36% weight. The contribution of the two indicators is also located in the top two indicators. Two cities focus on the direction of smart growth is also different. In summary, the differences between China and Western countries in urban planning are mainly focused on housing and public resources.
Short-range tensor interaction and high-density nuclear symmetry energy
Ang Li,Bao-An Li
Physics , 2011,
Abstract: Effects of the short-range tensor interaction on the density-dependence of nuclear symmetry energy are examined by applying an approximate expression for the second-order tensor contribution to the symmetry energy derived earlier by G.E. Brown and R. Machleidt. It is found that the uncertainty in the short-range tensor force leads directly to a divergent high-density behavior of the nuclear symmetry energy.
An Early Warning System for Regional Rain-Induced Landslide Hazard  [PDF]
Shengshan Hou, Ang Li, Bin Han, Pinggen Zhou
International Journal of Geosciences (IJG) , 2013, DOI: 10.4236/ijg.2013.43053

Landslide in alpine regions often causes heavy losses of both human lives and properties, most of the landslides are induced by heavy rainfall. In this paper, we put forward an early warning system of rain-induced landslide. From 2002, we carried on the demonstrative work of landslide monitoring and early warning in Yaan, Sichuan Province, China, and constructed the first county-scale landslide monitoring and early warning region. Yucheng District of Yaan City is located in the west of the Sichuan Basin, right in the intersection of SichuanBasin and the Tibetan Plateau. The slopes are made of Mesozoic sedimentary rock, sandstone inter-bedded with mudstone. Yucheng District has the title “sky funnel” because of the high precipitation, the annual precipitation is about 1750 mm. We carried out detailed landslide survey, and obtained the location, scale, characteristics, influence and triggering factors of the landslides. Then we assessed the regional landslide susceptibility. Based on the evolution law of the landslides, we selected ten factors to study the relationship between the factors and landslide. Using the bi-variate statistics method, we calculated the contribution to landslide from each factor, classified the susceptibility into four categories. We set up the regional rainfall monitoring network with 13 automatic CAWS600R rain gauges. Using the landslide survey data, we studied the rainfall influencing of the regional landslides. The one-day and three-day rainfall controls the occurrence of regional landslide. We also classified the triggering effect of rainfall into four categories. We presented a method to calculate the landslide danger degree using the susceptibility and triggering category. Utilizing the predicted rainfall data and real-time monitored rainfall data, together with the landslide susceptibility map, we developed a WebGIS-based landslide warning system, which greatly strengthened the capability for geohazard

Accumulation tests for FDR control in ordered hypothesis testing
Ang Li,Rina Foygel Barber
Statistics , 2015,
Abstract: Multiple testing problems arising in modern scientific applications can involve simultaneously testing thousands or even millions of hypotheses, with relatively few true signals. In this paper, we consider the multiple testing problem where prior information is available (for instance, from an earlier study under different experimental conditions), that can allow us to test the hypotheses as a ranked list in order to increase the number of discoveries. Given an ordered list of n hypotheses, the aim is to select a data-dependent cutoff k and declare the first k hypotheses to be statistically significant while bounding the false discovery rate (FDR). Generalizing several existing methods, we develop a family of "accumulation tests" to choose a cutoff k that adapts to the amount of signal at the top of the ranked list. We introduce a new method in this family, the HingeExp method, which offers higher power to detect true signals compared to existing techniques. Our theoretical results prove that these methods control a modified FDR on finite samples, and characterize the power of the methods in the family. We apply the tests to simulated data, including a high-dimensional model selection problem for linear regression. We also compare accumulation tests to existing methods for multiple testing on a real data problem of identifying differential gene expression over a dosage gradient.
Delineating effects of tensor force on the density dependence of nuclear symmetry energy
Chang Xu,Ang Li,Bao-An Li
Physics , 2012, DOI: 10.1088/1742-6596/420/1/012090
Abstract: In this talk, we report results of our recent studies to delineate effects of the tensor force on the density dependence of nuclear symmetry energy within phenomenological models. The tensor force active in the isosinglet neutron-proton interaction channel leads to appreciable depletion/population of nucleons below/above the Fermi surface in the single-nucleon momentum distribution in cold symmetric nuclear matter (SNM). We found that as a consequence of the high momentum tail in SNM the kinetic part of the symmetry energy $E^{kin}_{sym}(\rho)$ is significantly below the well-known Fermi gas model prediction of approximately $12.5 (\rho/\rho_0)^{2/3}$. With about 15% nucleons in the high momentum tail as indicated by the recent experiments at J-Lab by the CLAS Collaboration, the $E^{kin}_{sym}(\rho)$ is negligibly small. It even becomes negative when more nucleons are in the high momentum tail in SNM. These features have recently been confirmed by three independent studies based on the state-of-the-art microscopic nuclear many-body theories. In addition, we also estimate the second-order tensor force contribution to the potential part of the symmetry energy. Implications of these findings in extracting information about nuclear symmetry energy from nuclear reactions are discussed briefly.
When reputation enforces evolutionary cooperation in unreliable MANETs
Changbing Tang,Ang Li,Xiang Li
Computer Science , 2014,
Abstract: In self-organized mobile ad hoc networks (MANETs), network functions rely on cooperation of self-interested nodes, where a challenge is to enforce their mutual cooperation. In this paper, we study cooperative packet forwarding in a one-hop unreliable channel which results from loss of packets and noisy observation of transmissions. We propose an indirect reciprocity framework based on evolutionary game theory, and enforce cooperation of packet forwarding strategies in both structured and unstructured MANETs. Furthermore, we analyze the evolutionary dynamics of cooperative strategies, and derive the threshold of benefit-to-cost ratio to guarantee the convergence of cooperation. The numerical simulations verify that the proposed evolutionary game theoretic solution enforces cooperation when the benefit-to-cost ratio of the altruistic exceeds the critical condition. In addition, the network throughput performance of our proposed strategy in structured MANETs is measured, which is in close agreement with that of the full cooperative strategy.
An Abrupt Centennial-Scale Drought Event and Mid-Holocene Climate Change Patterns in Monsoon Marginal Zones of East Asia
Yu Li, Nai'ang Wang, Chengqi Zhang
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0090241
Abstract: The mid-latitudes of East Asia are characterized by the interaction between the Asian summer monsoon and the westerly winds. Understanding long-term climate change in the marginal regions of the Asian monsoon is critical for understanding the millennial-scale interactions between the Asian monsoon and the westerly winds. Abrupt climate events are always associated with changes in large-scale circulation patterns; therefore, investigations into abrupt climate changes provide clues for responses of circulation patterns to extreme climate events. In this paper, we examined the time scale and mid-Holocene climatic background of an abrupt dry mid-Holocene event in the Shiyang River drainage basin in the northwest margin of the Asian monsoon. Mid-Holocene lacustrine records were collected from the middle reaches and the terminal lake of the basin. Using radiocarbon and OSL ages, a centennial-scale drought event, which is characterized by a sand layer in lacustrine sediments both from the middle and lower reaches of the basin, was absolutely dated between 8.0–7.0 cal kyr BP. Grain size data suggest an abrupt decline in lake level and a dry environment in the middle reaches of the basin during the dry interval. Previous studies have shown mid-Holocene drought events in other places of monsoon marginal zones; however, their chronologies are not strong enough to study the mechanism. According to the absolutely dated records, we proposed a new hypothesis that the mid-Holocene dry interval can be related to the weakening Asian summer monsoon and the relatively arid environment in arid Central Asia. Furthermore, abrupt dry climatic events are directly linked to the basin-wide effective moisture change in semi-arid and arid regions. Effective moisture is affected by basin-wide precipitation, evapotranspiration, lake surface evaporation and other geographical settings. As a result, the time scales of the dry interval could vary according to locations due to different geographical features.
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