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1.
This paper targets at the problem of automatic semantic indexing of news videos by presenting a video annotation and retrieval system which is able to perform automatic semantic annotation of news video archives and provide access to the archives via these annotations. The presented system relies on the video texts as the information source and exploits several information extraction techniques on these texts to arrive at representative semantic information regarding the underlying videos. These techniques include named entity recognition, person entity extraction, coreference resolution, and semantic event extraction. Apart from the information extraction components, the proposed system also encompasses modules for news story segmentation, text extraction, and video retrieval along with a news video database to make it a full-fledged system to be employed in practical settings. The proposed system is a generic one employing a wide range of techniques to automate the semantic video indexing process and to bridge the semantic gap between what can be automatically extracted from videos and what people perceive as the video semantics. Based on the proposed system, a novel automatic semantic annotation and retrieval system is built for Turkish and evaluated on a broadcast news video collection, providing evidence for its feasibility and convenience for news videos with a satisfactory overall performance.  相似文献   
2.
针对现有基于双向Hash链技术的自愈组密钥分配方案不能抵抗撤销节点和新加入节点的共谋攻击问题,并进一步提高现有方案的性能,提出了一种适用于无线传感器网络的有效的抗共谋攻击的自愈组密钥分配方案。方案对传统的双向Hash链进行了结构性改造,在有撤销节点的会话中,用随机值替换前向密钥,使得已被撤销节点无法和新加入节点共谋获取它们未被授权的会话密钥,消除了共谋攻击对网络构成的安全威胁,更适用于俘获节点攻击高发的网络环境。方案还考虑了在实际网络环境中,并不是在每一个会话都有节点被撤销这一个实际情况,减少了通信开销和能量消耗。安全性和性能分析与仿真结果表明,方案在保证更好安全性的同时,降低了通信开销。  相似文献   
3.
The aim of this study is to examine the dye biosorption properties of lichen species called Cladonia convoluta and Evernia prunastri. Since lichens are extensively found in the environment, their suitability as a cheap adsorbent has been investigated in this study. The optimal parameters for textile dye biosorption were also determined. The dried lichen biomass showed better dye biosorption capacity than ash lichen biomass. C. convoluta had better dye biosorption capacity than E. prunastri. Dye biosorption rate was found as 71.41% at optimal conditions. This study concluded that C. convoluta was a successful and cheap biosorbent for treatment of water contaminated by Acid Red P-2BX dye.  相似文献   
4.
Chocolate compound was produced using ball mill refiner, and the effect of agitator shaft speed and refining time on the physical quality parameters (particle size, colour and steady‐state rheology) of compound chocolate was determined using response surface methodology. The shaft speed and refining time range were selected between 40–60 r.p.m. and 10–30 min, respectively. Determination coefficient of the models established for particle size, Newtonian viscosity and colour parameters (brightness, chroma and hue angle) were found to be very close to unity. Increasing shaft speed and time induced a reduction in particle size and an increase in viscosity of the samples. Temperature sweep test was also performed, and the obtained data were successfully fitted to Arrhenius equation to calculate the corresponding parameters representing temperature dependency of the compounds. The results highlighted that the establishment of such models can provide essential information in terms of optimisation of production processes regarding usage purpose of the compound chocolate.  相似文献   
5.
6.
Cerium oxide supported 5-Amino-2,4-dichlorophenol-3,5-ditertbutylsalisylaldimine-Nickel complex for the first time was used to produce H2 from hydrolysis of sodium borohydride. Cerium oxide supported Nickel complex catalyzed hydrolysis system was studied depend on temperature, concentration of sodium hydroxide, amount of Cerium oxide supported Ni complex catalyst, concentration of Ni complex and concentration of sodium borohydride. Cerium oxide supported Ni(II) complex display highly effective catalytic activity in sodium borohydride hydrolysis reaction. The obtained Cerium oxide supported Ni(II) complex catalyst was characterized by using Fourier Transform Infrared Spectroscopy, Scanning Electron Microscope, Transmission Electron Microscope, Brunauer-Emmett-Teller Surface Area Analysis, X-Ray Diffraction Analysis techniques. The catalyst stability was tested, even the fifth recycle the catalytic activity was maintained at 100%. Additionally the proposed Cerium oxide supported-Ni (II) complex catalyzed sodium borohydride hydrolysis mechanism was determined carefully. The experimental results showed that Cerium oxide supported Ni (II) complex catalyst accelerate sodium borohydride hydrolysis with 43,392 and 19,630 mL H2 gcat?1 min?1 hydrogen production rates at 50 °C and 30 °C respectively and 20,587 kJ mol?1 activation energy.  相似文献   
7.
The Turkish contracting sector has an enviable reputation for operating in high-risk international markets. The sector’s ability to respond to market instability could meaningfully be construed as sectoral-level capability. We aim to demonstrate how history can be mobilised in a formalised “strategy text” to create a strategic narrative on the sectoral level. The Geography of Contractors as published by the Turkish Contractors Association (TCA) ostensively portrays the strategic development of Turkish international contractors over four decades. Such quasi-historical narratives are routinely mobilised for the purposes of creating a shared memory on the sectoral level. The chosen strategy text draws from multiple narrative fragments derived from past experience to generate a strategic agenda for the future. The representation given to multiple voices reflects the pluralistic nature of strategy making praxis. The overarching strategy narrative reflects a performative intent in legitimising some practices whilst discrediting others. Narrative analysis demonstrates the way in which actors, actions and events are positioned within a plot structure, with direct implications for the enactment of future strategic practices. The findings suggest that strategic actions can only ever be identified in retrospect and that such arguments are always made with an eye on the future.  相似文献   
8.
SiAlON ceramics with high hardness and high toughness can be made through designing α/β-SiAlON composites. An important advantage of α-SiAlON phase is that the amount of intergranular phase is reduced by the transient liquid phase being absorbed into the matrix of α-SiAlON phase during sintering. But, the thermal stability of the α-SiAlON phase is an important concern for α/β-SiAlON composites especially at high temperatures. The use of different types of single or multiple cations during fabrication directly affects resultant microstructures and mechanical behavior of α/β-SiAlON composites. In this study, the creep behavior of a multi-cation (Y, Sm and Ca) doped α/β-SiAlON composite, in which aluminum-containing nitrogen melilite solid solution phase was designed as intergranular phase, was investigated by four-point bending creep tests under stresses from 50 to 150 MPa and at temperatures from 1300 °C to 1400 °C in air. The stress exponent was determined to be 1.6 ± 0.13 at 1400 °C and the creep activation energy was calculated to be 692 ± 37 kJ/mol−1. Grain boundary sliding coupled with diffusion was identified as the rate-controlling creep mechanism for the α/β-SiAlON composite.  相似文献   
9.
针对战场信息的不确定性和不完整性的问题,建立基于灰色局势决策法的炮兵火力方案优选模型。该模型运用灰色理论,客观全面地反映每个火力方案在每个对策下的特征,并对各火力方案的优劣进行排序。实例分析证明:该方法为炮兵指挥员选择火力方案提供了一种高效、科学的辅助决策方法。  相似文献   
10.
Glucose isomerase (GI) from Streptomycesrubiginosus was immobilized covalently onto Eupergit C 250 L made by copolymerization of N,N-methylene-bis-methacrylamide, glycidyl methacrylate, allyl glycidyl ether and methacrylamide. The catalytic efficiency of immobilized GI in isomerization of glucose to fructose was found as three fold higher than that of free GI. The residual activity of immobilized GI after 18 reuses in a batch type stirred reactor was about 85% of its initial activity. The thermal stability of immobilized GI was almost same with that of the free GI at 60 °C for 18 h preincubation time. The residual activities of immobilized GI when stored at 5 °C and 25 °C for four weeks were 72% and 69% of the initial activity, respectively. However, free GI retained 88% and 78% of its initial activity at 5 °C and 25 °C upon four weeks storage, respectively. Thus, the use of Eupergit C 250 L immobilized GI instead of free GI is suggested in enzymatic isomerization of glucose to fructose.  相似文献   
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