The aim of this work is to study the interaction of spoken words and images that are used within programs targeted to popularize knowledge among teenagers. We will look into the program Bit@bit developed by Television...The aim of this work is to study the interaction of spoken words and images that are used within programs targeted to popularize knowledge among teenagers. We will look into the program Bit@bit developed by Television de Catalunya, which is intended to disseminate computer concepts, tools and procedures. In this kind of program, one can find spoken language （on/off screen voices, interviews, etc.）, other oral material （sounds, music, songs）, written language （descriptions, title sequences, inserts and Uniform Resource Locator, or electronic addresses）, and other visual material （film cut images, advertising, other TV programs, cartoons, films, both location or studio images, depicting reality, or computer screens, or logotypes）. The profusion of multimodal elements used in this program helps to keep the young audience＇s attention. The use of references to their world or knowledge, as a target group, is based on interplay among different semiotic strategies. At the same time, the entire program＇s multi-segmentation into short video clips, combined with a fast paced sound track helps its audience to understand the specialized explanations presented. Of all the multimodal wealth that the program presents, we will concentrate only on the relationship between the words and the images （leaving other secondary semiotics to one side）, the main strategy for achieving the objective of transmitting knowledge and winning adolescent audiences.展开更多
A test items knowledge library system of for adaptive learning is proposed in this paper. The first step is to carry out the quantity and quality analysis of the test items by using the Bloom＇s revised taxonomy and s...A test items knowledge library system of for adaptive learning is proposed in this paper. The first step is to carry out the quantity and quality analysis of the test items by using the Bloom＇s revised taxonomy and scale anchoring respectively to produce the characteristics for test items. A smoothing method of arbitrary anchoring revised from scale anchoring is first proposed to make tests more accurate in distinguishing test levels. In addition, raised three dimensional indicators based on the Bloom＇s revised taxonomy are adopted to validate test contents and therefore it concretely describes the examining function of items. The items obtained have the precise and concrete properties; an item knowledge library is therefore constructed combining teaching materials and items using the technologies of ontology and knowledge management. Finally, a knowledge library system of test items is established to achieve the purpose of adaptive learning for learners.展开更多
Time reversal processing （TRP） might be regarded as matched field processing with known environmental knowledge. However, the performance of TRP is degraded in an uncertain environment. A technique based on the Maxi...Time reversal processing （TRP） might be regarded as matched field processing with known environmental knowledge. However, the performance of TRP is degraded in an uncertain environment. A technique based on the Maximin criterion is pro- posed for enhancing the robustness of TRP in a waveguide with uncertain water depth. The relationship between the water depth and the focal spot translation is examined based on the waveguide-invariant theory. Then the time reversal transmissiou scheme with the Maximin criterion is performed to maximize the minimum transmission power on a target of interest. At the receiving end, coherent summation operation is carried out over the received data by a reception focusing bank. If it is neces- sary to enhance the target echo further, the iterative time reversal can be considered where the target echo corresponding to the first time reversal transmission is regarded as a secondary source. Numerical simulations and experimental results of the target localization in a waveguide tank have verified the effectiveness of robust TRP.展开更多
文摘The aim of this work is to study the interaction of spoken words and images that are used within programs targeted to popularize knowledge among teenagers. We will look into the program Bit@bit developed by Television de Catalunya, which is intended to disseminate computer concepts, tools and procedures. In this kind of program, one can find spoken language （on/off screen voices, interviews, etc.）, other oral material （sounds, music, songs）, written language （descriptions, title sequences, inserts and Uniform Resource Locator, or electronic addresses）, and other visual material （film cut images, advertising, other TV programs, cartoons, films, both location or studio images, depicting reality, or computer screens, or logotypes）. The profusion of multimodal elements used in this program helps to keep the young audience＇s attention. The use of references to their world or knowledge, as a target group, is based on interplay among different semiotic strategies. At the same time, the entire program＇s multi-segmentation into short video clips, combined with a fast paced sound track helps its audience to understand the specialized explanations presented. Of all the multimodal wealth that the program presents, we will concentrate only on the relationship between the words and the images （leaving other secondary semiotics to one side）, the main strategy for achieving the objective of transmitting knowledge and winning adolescent audiences.
文摘A test items knowledge library system of for adaptive learning is proposed in this paper. The first step is to carry out the quantity and quality analysis of the test items by using the Bloom＇s revised taxonomy and scale anchoring respectively to produce the characteristics for test items. A smoothing method of arbitrary anchoring revised from scale anchoring is first proposed to make tests more accurate in distinguishing test levels. In addition, raised three dimensional indicators based on the Bloom＇s revised taxonomy are adopted to validate test contents and therefore it concretely describes the examining function of items. The items obtained have the precise and concrete properties; an item knowledge library is therefore constructed combining teaching materials and items using the technologies of ontology and knowledge management. Finally, a knowledge library system of test items is established to achieve the purpose of adaptive learning for learners.
基金supported by the National Natural Science Foundation of China(Grant Nos.60872066 and 61171148)the National High-Tech R&D Program of China(Grant No.2009AA093601-3)
文摘Time reversal processing （TRP） might be regarded as matched field processing with known environmental knowledge. However, the performance of TRP is degraded in an uncertain environment. A technique based on the Maximin criterion is pro- posed for enhancing the robustness of TRP in a waveguide with uncertain water depth. The relationship between the water depth and the focal spot translation is examined based on the waveguide-invariant theory. Then the time reversal transmissiou scheme with the Maximin criterion is performed to maximize the minimum transmission power on a target of interest. At the receiving end, coherent summation operation is carried out over the received data by a reception focusing bank. If it is neces- sary to enhance the target echo further, the iterative time reversal can be considered where the target echo corresponding to the first time reversal transmission is regarded as a secondary source. Numerical simulations and experimental results of the target localization in a waveguide tank have verified the effectiveness of robust TRP.
