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Relevance feedback has recently emerged as a solution to the problem of improving the retrieval performance of an image retrieval
system based on low-level information such as color, texture and shape features. Most of the relevance feedback approaches
limit the utilization of the user’s feedback to a single search session, performing a short-term learning. In this paper we
present a novel approach for short and long term learning, based on the definition of an adaptive similarity metric and of
a high level representation of the images. For short-term learning, the relevant and non-relevant information given by the
user during the feedback process is employed to create a positive and a negative subspace of the feature space. For long-term
learning, the feedback history of all the users is exploited to create and update a representation of the images which is
adopted for improving retrieval performance and progressively reducing the semantic gap between low-level features and high-level
semantic concepts. The experimental results prove that the proposed method outperforms many other state of art methods in
the short-term learning, and demonstrate the efficacy of the representation adopted for the long-term learning.
相似文献
Annalisa FrancoEmail: |
85.
Designed 3 experiments to assess 24 preschool (mean age 64.63 mo), 24 1st-grade (mean age 76.25 mo), and 24 2nd grade (mean age 88.61 mo) children's understanding of the term word. A modified aural discrimination task was used in which Ss were required to discriminate word from nonword stimuli along only 1 dimension at a time. Exp I tested Ss' discrimination of words and sounds. Exp II examined word–phrase differentiation. Both of these experiments followed previous research in examining children's comprehension of the term word in relation to nouns. Exp III examined Ss' understanding of word with stimuli from a variety of form classes. Results indicate that Ss' word concepts have been underestimated in past research suggesting that young children lack an adequate word concept: although preschool Ss did not understand the term properly, by 1st grade word was understood. These experiments also show that Ss benefited from brief training in which they were taught to attach the metalinguistic label word to their developing concept of the word as a unit of spoken language. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
86.
陆泓 《安徽冶金科技职业学院学报》2012,22(2):63-64,77
专业英语教学难点有三:专业技术词汇;被动句式与非限定动词短语;长句.专业英语翻译学习的第一目标是准确与通畅. 相似文献
87.
水电站群长期典型日调峰电量最大模型研究 总被引:2,自引:1,他引:1
针对水电站群长期优化调度与典型日负荷分配的结合问题,建立了典型日调峰电量最大模型,采用逐次切负荷算法进行各长期调度时段典型日负荷分配,并将其嵌入长期优化调度模型。以各时段典型日剩余负荷过程最大值最小化作为优化目标,从而将长期优化调度和典型日负荷分配统一于一个模型中。通过凝聚函数法进行目标函数转换,以逐步优化算法求解。实例研究表明,该模型能够体现水电长期调度的电力电量平衡需求,结果比仅考虑平均负荷的模型更合理,并能够同时得到长期调度计划和典型日负荷分配方案,对电网水火电联合调度背景下的水电站群长期优化调度问题具有实际应用价值。 相似文献
88.
《国际计算机数学杂志》2012,89(7):1147-1159
Singularly perturbed two-point boundary-value problems (BVPs) for fourth-order ordinary differential equations (ODEs) with a small positive parameter multiplying the highest derivative with a discontinuous source term is considered. The given fourth-order BVP is transformed into a system of weakly coupled systems of two second-order ODEs, one without the parameter and the other with the parameter ? multiplying the highest derivative, and suitable boundary conditions. In this paper a computational method for solving this system is presented. In this method we first find the zero-order asymptotic approximation expansion of the solution of the weakly coupled system. Then the system is decoupled by replacing the first component of the solution by its zero-order asymptotic approximation expansion of the solution in the second equation. Then the second equation is solved by the numerical method, which is constructed for this problem and which involves an appropriate piecewise-uniform mesh. 相似文献
89.
为研究黄河口的水沙输移规律,采用基于无结构三角网格下的有限体积法建立了平面二维水沙数学模型.模型中分别采用不同方法处理粘性和非粘性沙的输移源项,并引入经验证的粘性沙输移源项改进公式.采用已有的概化水槽冲淤试验资料对模型进行了验证,然后应用于1982年6月至1983年5月期间黄河口水沙输移的数值模拟,计算得到的潮位过程及冲淤量与实测资料符合较好,结果表明模型能够较好地模拟考虑粘性沙运动的黄河口非均匀沙不平衡输移.最后比较了不同泥沙输移源项处理方式对模拟结果的影响,计算表明在黄河口水沙输移数值模拟中需要采用非均匀沙模型并同时考虑粘性和非粘性泥沙的输移. 相似文献
90.
《国际计算机数学杂志》2012,89(3):523-536
In this paper, a new method of analysis for a singular system-based electronic circuits using the Runge–Kutta (RK)–Butcher algorithm is presented for linear time-invariant and time-varying cases. The discrete solutions obtained using the RK–Butcher algorithms are compared with the exact solutions of the electronic circuit problem and are found to be very accurate. Stability regions for the Single term walsh series method and the RK–Butcher algorithms are presented. Error graphs for inductor currents and capacitor voltages are presented in a graphical form to show the efficiency of this method. This RK–Butcher algorithm can be easily implemented in a digital computer and the solution can be obtained for any length of time. 相似文献