| 21. |
- Pang, Zhibo, et al.
(författare)
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Mobile and Wide Area Deployable Sensor System for Networked Services
- 2009
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Ingår i: 2009 IEEE SENSORS. - NEW YORK : IEEE. - 9781424445486 ; , s. 1329-1332
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Konferensbidrag (refereegranskat)abstract
- A mobile and wide area deployable wireless sensor system, including hardware and software, is developed to enhance the mobility, deployment and capability of wireless sensors for networked services. Due to the dual-layer dual-directional wireless communication capability of a novel WAN-SAN coherent architecture and the removal of fix-installed gateway, all sensor nodes are remotely controllable and seamlessly integrated to internet services. Hardware modules are optimized for ultra low power and compact size. Abstract and extendable application interface is developed, based on SMS and TCP/UDP protocol, to be integrated easily into existing service systems. Hierarchical CPS-LPS Adaptive Localization, is supported based on CPS, wireless cellular ID, RFID, IR-UWB and inertial prediction. Specific data compression technique is adopted for high density data source. Finally, Fresh Food Tracking service is presented as an application example, including some field test data.
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| 22. |
- Qiu, Min, et al.
(författare)
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Silicon micro-cavities and their system applications
- 2009
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Ingår i: PHOTONICS PACKAGING, INTEGRATION, AND INTERCONNECTS IX. - : SPIE. - 9780819474674
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Konferensbidrag (refereegranskat)abstract
- We experimentally demonstrate resonance-splitting and enhanced notch as a result of the mutual mode coupling in silicon ring resonator. Dense wavelength conversions, wavelength multicasting and optical up-converter are demonstrated in the split silicon ring resonator. A temporal differentiator and format conversion from NRZ to AMI are demonstrated utilizing the filtering effect of ring resonator. Photonic phase shifter and delay line are demonstrated utilizing the phase shift of ring resonator.
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| 23. |
- Sodergren, Erica, et al.
(författare)
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The genome of the sea urchin Strongylocentrotus purpuratus.
- 2006
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 314:5801, s. 941-52
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Tidskriftsartikel (refereegranskat)abstract
- We report the sequence and analysis of the 814-megabase genome of the sea urchin Strongylocentrotus purpuratus, a model for developmental and systems biology. The sequencing strategy combined whole-genome shotgun and bacterial artificial chromosome (BAC) sequences. This use of BAC clones, aided by a pooling strategy, overcame difficulties associated with high heterozygosity of the genome. The genome encodes about 23,300 genes, including many previously thought to be vertebrate innovations or known only outside the deuterostomes. This echinoderm genome provides an evolutionary outgroup for the chordates and yields insights into the evolution of deuterostomes.
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| 24. |
- Su, Y., et al.
(författare)
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Optical signal processing in SOI waveguide devices
- 2009
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Ingår i: 2009 14th OptoElectronics and Communications Conference, OECC 2009. - 9781424441037 ; , s. -733
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Konferensbidrag (refereegranskat)abstract
- We experimentally demonstrate optical signal processing in silicon ring resonators, including slow-light delay of digital and microwave photonic signals, dense wavelength conversions/multicasting, optical up-convertion, format conversions, temporal differentiation, and bio-sensing.
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| 25. |
- Vinel, Alexey, 1983-, et al.
(författare)
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Efficient Request Mechanism Usage in IEEE 802.16
- 2006
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Ingår i: Global Telecommunications Conference, GLOBECOM 2006. - Piscataway, NJ : IEEE Press. - 1424403561 - 9781424403561 - 142440357X - 9781424403578 ; , s. 1-5
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Konferensbidrag (refereegranskat)abstract
- IEEE 802.16 protocols for metropolitanbroadband wireless access systems have been standardizedrecently. According to the standard, a subscriber station candeliver bandwidth request messages to a base station bynumerous methods. This paper provides both the simulation andanalytical models for the investigation of specified random accessmethod, which is compared with centralized polling and stationgroupingmechanisms. Based on the assumptions of Bernoullirequest arrival process and ideal channel conditions, the meandelay of a request transmission is evaluated for varying numberof transmission opportunities and different arrival rates.
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| 26. |
- Yang, Tao, et al.
(författare)
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A spatial assessment of hydrologic alteration caused by dam construction in the middle and lower Yellow River, China
- 2008
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Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 22:18, s. 3829-3843
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Tidskriftsartikel (refereegranskat)abstract
- The ‘range of variability approach’ (RVA) and mapping technique are used to investigate the spatial variability of hydrologic alterations (HA) due to dam construction along the middle and lower Yellow River, China, over the past live decades. The impacts of climate variability oil hydrological process have been removed during wet and dry periods and the focus IS Oil the impacts of human activities, Such as dam construction, on hydrological processes. Results indicate the following: (1) The impacts of the Sanmenxia reservoir oil the hydrologic alteration are relatively slight with a mean HA value of 0.48, ranking in the last place among the four large reservoirs. (2) Xiaolangdi reservoir has significantly changed the natural flow regime downstream with mean HA value of 0.56, ranking it in first place among the large reservoirs. (3) The results of ranked median degrees of 33 hydrologic alteration indicators for 10 stations in the Yellow River show that the hydrologic alteration of Huayuankou ranks the highest among 10 stream gauges. (4) Impacts of reservoirs on hydrological processes downstream of the dams are closely associated with the regulating activities of the reservoirs. At the same time, alterations of streamflow regimes resulting from climatic changes (e.g. precipitation variability) make the situation more complicated and more hydrological observations will be necessary for further analysis. The results of the current study will be greatly beneficial to the regional water resources management and restoration of eco-environmental systems in the middle and lower Yellow River characterized by intensified dam construction under a changing environment. Copyright (C) 2008 John Wiley & Sons, Ltd.
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| 27. |
- Zhang, Hongwei, et al.
(författare)
-
Prediction of Solidification Microstructure and Columnar-to-equiaxed Transition of Al-Si Alloy by Two-dimensional Cellular Automaton with "Decentred Square" Growth Algorithm
- 2009
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 49:7, s. 1000-1009
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Tidskriftsartikel (refereegranskat)abstract
- A Cellular Automaton (CA)-Finite Difference (FD) coupling model was developed to analyze the evolution of solidification microstructure and the columnar-to-equiaxed transition (CET) in AI-Si alloy. Kobayashi's microsegregation equation was adopted to describe the solute diffusion in solid phase, and a "decentred square" growth algorithm with coordinate transformation was performed to describe the grain growth and the entrapment of neighbor cells. Through the examination on the effects of operation parameters and nucleation parameters on solidification morphologies, it was found that the length of columnar grains is controlled by the dendrite tip growth kinetics, and that the width of columnar grains is controlled by the implicit relationship between nucleation density and cooling rate at ingot surface. It was also found that the size of equiaxed grains is controlled by the competition of the nucleation and the grain growth. With the controllability of nucleation density in the bulk of liquid for equiaxed grain size, the nucleant and the nucleation density in actual AI-Si alloy were estimated. Both of the CET criteria based on the solidification path by CA-FD coupling model and the one based on the curves of critical temperature gradient conditions by Hunt's model were strongly dependent on nucleation undercooling and Si concentration. A good agreement was obtained between these two.
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| 28. |
- Zhang, Qiang, et al.
(författare)
-
Abrupt behaviors of the streamflow of the Pearl River basin and implications for hydrological alterations across the Pearl River Delta, China
- 2009
-
Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694 .- 1879-2707. ; 377, s. 274-283
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we analyze the long streamflow series of three hydrological stations of the lower Pearl River basin and the streamflow ratio between Makou and Sanshui stations by using statistical techniques. Furthermore, we also attempt to address influences of precipitation and human activities (human-induced deepening of river channels) on streamflow ratio. The results indicate that: (1) the streamflow variations show remarkable relations with precipitation changes in West and East River basins, implying tremendous influences of climate changes on hydrological processes. Decreasing precipitation was observed in North River basin. However, the streamflow, amount of the Sanshui station largely increased due to enlarged streamflow allocation from the West River to the North River; (2) increasing streamflow ratio of Sanshui/(Makou + Sanshui) is the result of morphological changes (downcut) of river channels in the upper Pearl River Delta. The fast downcut of river channels is mainly due to intensive sand mining. Larger magnitude of increase in streamflow ratio corresponds well to the higher intensity of in-channel sand dredging; (3) after late-1990s, decreasing precipitation of the Pearl River basin abates the streamflow amount and also the streamflow ratio. The influences of human activities and climate changes are varying in different time intervals and in different river basins. Due to tremendous impacts of increased streamflow ratio between Sanshui and Makou station. relations between streamflow and precipitation relations in the North River basin are not statistically good. This study helps to improve understandings of the causes underlying altered streamflow variations in the lower Pearl River basin and the hydrological alterations within the Pearl River Delta region. (C) 2009 Elsevier B.V. All rights reserved.
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| 29. |
- Zhang, Qiang, et al.
(författare)
-
Changing properties of precipitation concentration in the Pearl River basin, China
- 2009
-
Ingår i: Stochastic environmental research and risk assessment (Print). - : Springer Science and Business Media LLC. - 1436-3240 .- 1436-3259. ; 23:3, s. 377-385
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, precipitation concentrations across the Pearl River basin and the associated spatial patterns are analyzed based on daily precipitation data of 42 rain gauging stations during the period 1960-2005. Regions characterized by the different changing properties of precipitation concentration index (CI) are identified. The southwest and northeast parts of the Pearl River basin are characterized by lower and decreasing precipitation CI; the northwest and south parts of the study river basin show higher and increasing precipitation CI. Higher but decreasing precipitations CI are found in the West and East River basin. Comparison of precipitation CI trends before and after 1990 shows that most parts of the Pearl River basin are characterized by increasing precipitation CI after 1990. Decreasing precipitation CI after 1990 (compared to precipitation CI changes before 1990) is observed only in a few stations located in the lower Gui River and the lower Yu River. Significant increasing precipitation CI after 1990 is detected in the West River, lower North River and upper Beipan River. These changes of precipitation CI in the Pearl River basin are likely to be associated with the consequences of the well-evidenced global warming. These findings can contribute to basin-scale water resource management and conservation of ecological environment in the Pearl River basin.
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| 30. |
- Zhang, Qiang, et al.
(författare)
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Multifractal analysis of streamflow records of the East River basin (Pearl River), China
- 2009
-
Ingår i: Physica A. - : Elsevier BV. - 0378-4371 .- 1873-2119. ; 388:6, s. 927-934
-
Tidskriftsartikel (refereegranskat)abstract
- Scaling behaviors of the long daily streamflow series of four hydrological stations (Longchuan (1952-2002), Heyuan (1951-2002), Lingxia (1953-2002) and Boluo (1953-2002)) in the mainstream East River, one of the tributaries of the Pearl River (Zhujiang River) basin, were analyzed using multifractal detrended fluctuation analysis (MF-DFA). The research results indicated that streamflow series of the East River basin are characterized by anti-persistence. MF-DFA technique showed similar scaling properties in the streamflow series of the East River basin on shorter time scales, indicating universal scaling properties over the East River basin. Different intercept values of the fitted lines Of log-log Curve of F-q(s) versus s implied hydrological regulation of water reservoirs. Based on the numerical results, we suggested that regulation activities by water reservoirs Could not impact the scaling properties of the streamflow series. The regulation activities by water reservoir only influenced the fluctuation magnitude. Therefore, we concluded that the streamflow variations were mainly the results of climate changes, and precipitation variations in particular. Strong dependence of generalized Hurst exponent h(q) on q demonstrated multifractal behavior of streamflow series of the East River basin, showing ‘universal’ multifractal behavior of river runoffs. The results of this study may provide valuable information for prediction and assessment of water resources under impacts of climatic changes and human activities in the East River basin. (C) 2008 Elsevier B.V. All rights reserved.
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