879 resultados para Skill
Resumo:
A group of 28 fisherwomen who attended demonstration on three subjects, namely, preparation of fish wafers, fish pickles and fish soup powder showed significant knowledge and skill gain for all the three messages. The total knowledge and skill gain was maximum for preparation of fish wafers followed by that for preparation of fish soup powder and fish pickles.
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Motor task variation has been shown to be a key ingredient in skill transfer, retention, and structural learning. However, many studies only compare training of randomly varying tasks to either blocked or null training, and it is not clear how experiencing different nonrandom temporal orderings of tasks might affect the learning process. Here we study learning in human subjects who experience the same set of visuomotor rotations, evenly spaced between -60° and +60°, either in a random order or in an order in which the rotation angle changed gradually. We compared subsequent learning of three test blocks of +30°→-30°→+30° rotations. The groups that underwent either random or gradual training showed significant (P < 0.01) facilitation of learning in the test blocks compared with a control group who had not experienced any visuomotor rotations before. We also found that movement initiation times in the random group during the test blocks were significantly (P < 0.05) lower than for the gradual or the control group. When we fit a state-space model with fast and slow learning processes to our data, we found that the differences in performance in the test block were consistent with the gradual or random task variation changing the learning and retention rates of only the fast learning process. Such adaptation of learning rates may be a key feature of ongoing meta-learning processes. Our results therefore suggest that both gradual and random task variation can induce meta-learning and that random learning has an advantage in terms of shorter initiation times, suggesting less reliance on cognitive processes.
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Technological investment is a key driver of innovation and the evaluation of technology potential is becoming increasingly important in this context. There is a range of approaches and tools for developing an understanding of the value of technology. However the process of communicating this potential to possible customers is not well documented in terms of theory and practice and falls outside the skill set of many technologists. This paper seeks to integrate the concepts of marketing and consultative selling into making business cases for new technologies. It describes an exploratory study which results in an outline process activity model for technologists wishing to build an effective business case for securing investment internally or when selling a technology externally. Following a review of literature, we suggest that there is potential to learn from market research and consultative sales techniques, and propose a five step process. The work has been industrially validated and forms a novel foundation for further development. © 2012 Elsevier Inc.
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基于CMOS器件的离散性机理及误差消除对策,研究了高速、高精度嵌入式CMOS数/模转换器(DAC)IP核的设计与实现。采用行、列独立译码的二次中心对称电流源矩阵结构,优化了电流源开关电路结构与开关次序;利用Cadence的Skill语言独立开发电流源矩阵的版图排序和布线方法。在0.6μm N阱CMOS工艺平台下,12-bitDAC的微分线性误差和积分线性误差分别为1LSB和1.5LSB,在采样率为150MHz、工作电源为3.3V时的平均耗为140mW。流片一次成功,主要性能指标满足设计要求。
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With the intermediate-complexity Zebiak-Cane model, we investigate the 'spring predictability barrier' (SPB) problem for El Nino events by tracing the evolution of conditional nonlinear optimal perturbation (CNOP), where CNOP is superimposed on the El Nino events and acts as the initial error with the biggest negative effect on the El Nino prediction. We show that the evolution of CNOP-type errors has obvious seasonal dependence and yields a significant SPB, with the most severe occurring in predictions made before the boreal spring in the growth phase of El Nino. The CNOP-type errors can be classified into two types: one possessing a sea-surface-temperature anomaly pattern with negative anomalies in the equatorial central-western Pacific, positive anomalies in the equatorial eastern Pacific, and a thermocline depth anomaly pattern with positive anomalies along the Equator, and another with patterns almost opposite to those of the former type. In predictions through the spring in the growth phase of El Nino, the initial error with the worst effect on the prediction tends to be the latter type of CNOP error, whereas in predictions through the spring in the decaying phase, the initial error with the biggest negative effect on the prediction is inclined to be the former type of CNOP error. Although the linear singular vector (LSV)-type errors also have patterns similar to the CNOP-type errors, they cover a more localized area than the CNOP-type errors and cause a much smaller prediction error, yielding a less significant SPB. Random errors in the initial conditions are also superimposed on El Nino events to investigate the SPB. We find that, whenever the predictions start, the random errors neither exhibit an obvious season-dependent evolution nor yield a large prediction error, and thus may not be responsible for the SPB phenomenon for El Nino events. These results suggest that the occurrence of the SPB is closely related to particular initial error patterns. The two kinds of CNOP-type error are most likely to cause a significant SPB. They have opposite signs and, consequently, opposite growth behaviours, a result which may demonstrate two dynamical mechanisms of error growth related to SPB: in one case, the errors grow in a manner similar to El Nino; in the other, the errors develop with a tendency opposite to El Nino. The two types of CNOP error may be most likely to provide the information regarding the 'sensitive area' of El Nino-Southern Oscillation (ENSO) predictions. If these types of initial error exist in realistic ENSO predictions and if a target method or a data assimilation approach can filter them, the ENSO forecast skill may be improved. Copyright (C) 2009 Royal Meteorological Society
Resumo:
A hybrid coupled ocean-atmosphere model is designed, which consists of a global AGCM and a simple anomaly ocean model in the tropical Pacific. Retroactive experimental predictions initiated in each season from 1979 to 1994 are performed. Analyses indicate that: (1) The overall predictive capability of this model for SSTA over the central-eastern tropical Pacific can reach one year, and the error is not larger than 0.8 degrees C. (2) The prediction skill depends greatly on the season when forecasts start. However, the phenomenon of SPB (spring prediction barrier) is not found in the model. (3) The ensemble forecast method can effectively improve prediction results. A new initialization scheme is discussed.
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In this letter, a new wind-vector algorithm is presented that uses radar backscatter sigma(0) measurements at two adjacent subscenes of RADARSAT-1 synthetic aperture radar (SAR) images, with each subscene having slightly different geometry. Resultant wind vectors are validated using in situ buoy measurements and compared with wind vectors determined from a hybrid wind-retrieval model using wind directions determined by spectral analysis of wind-induced image streaks and observed by colocated QuikSCAT measurements. The hybrid wind-retrieval model consists of CMOD-IFR2 [applicable to C-band vertical-vertical (W) polarization] and a C-band copolarization ratio according to Kirchhoff scattering. The new algorithm displays improved skill in wind-vector estimation for RADARSAT-1 SAR data when compared to conventional wind-retrieval methodology. In addition, unlike conventional methods, the present method is applicable to RADARSAT-1 images both with and without visible streaks. However, this method requires ancillary data such as buoy measurements to resolve the ambiguity in retrieved wind direction.
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介绍了一种排爆机器人模拟训练系统.该系统提供了友好的人机交互界面,使操作人员可以进行各种模拟训练,并提高操作水平.重点介绍了该模拟训练系统的体系结构及关键实现技术,包括排爆机器人及其工作环境的建模方法、机器人运动学和动力学简化模型、碰撞检测和技能评定等.通过实验,证明了该模拟训练系统的可行性和有效性.
Resumo:
作者设计并实现了一个基于多变元逐步回归的二叉树分类器.在树结构和特征子集的选择中采用了穷举法,比有限制条件的选择更合理更优化.用 FORTRAN 语言实现的“遍历”二叉树,充分利用了 FORTRAN 处理可调数组的能力,并采取适当技巧,从而最大限度地利用了计算机内存.该通用分类器,可用来对任何具有统计数据的模式进行分类.在对白血球的分类中,取得了五类97%,六类92.2%的高识别率.
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The estimation of Time to Collision (TTC) related to avoiding collisions or making interceptions is an important cognitive ability for individuals. A number of studies have been carried out on this topic and related theories are developed. One of the most famous theories is the τ Theory. Based on the τ Theory, researches have found that visual information and physical information of moving objects would influent the TTC estimation. Are there any other factors that can affect people’s TTC estimation? A mixed design was used to examine the TTC estimation by different types of participants (professional drivers / people can not drive), with different moving objects (car/tricycle), under different speed (slow/fast) and direction (left to right / right to left) in Occlusion Paradigm. There were 21 professional drivers and 20 individuals who cannot drive participated in the experiment which was displayed on a computer. Participants were asked to click the button when he/she believed that the moving object had just contacted the red line. E-prime was used to establish the whole experimental environment and the RT was recorded at the same time. The results revealed that: (1) there is significant different TTC estimation between car and tricycle; (2) the professional drivers have more accurate TTC estimation than people do not drive. We can come to conclusion that conceptual information and driving skill could affect TTC estimation.
Resumo:
[Abstract] Verbal communication strategy (VCS) refers to a programmed knowledge applied by individuals to understand and express intentions via language symbols in their realization of communicative objectives according to social conventions. As an important index of social development, verbal communication strategy has provided a new perspective for social skill studies. However, more work has to be done in the investigation of LD children’s VCS developmental pattern and affecting mechanism. Through contextual test, structured interview and role-play, the present study, by adopting integrated measurements of instrumental and interpersonal effectiveness, explored the developmental characteristics of Chinese learning-disabled primary school children across 3-6th grades at both comprehension and application levels. Then, their social perspective-taking performance and verbal retelling competence of each participant were examined, on the basis of which, path analysis was conducted, with social perspective-taking, verbal retelling and verbal communication strategy comprehension as independent variables, to reveal the inner mechanism affecting LD children’s application of verbal communication strategy. Finally, an intervention study was carried out through a combination of polite request strategy understanding lessons and social perspective-taking training dramas. The results indicate that:(1) No significant grade differences were found in LD group for polite request strategy, while significant differences were reported across different grades of non-LD children. For indirect reply strategy, significant grade and gender differences were found among LD children, but the developmental trajectory between the two groups was different. For both polite request and indirect reply strategies, the strategy comprehension level of LD children was significantly lower than those without learning disabilities. (2) No significant grade and gender differences were found in LD group in their application of polite request strategy, while for non-LD children, significant differences were reported across different grades. For indirect reply strategy, both LD and non-LD groups exhibited similar developmental characteristics. Significant group differences only exist in the over-all application level of polite request strategies, not in indirect reply strategies. However, the differences of the latter between the two groups were found at significant level only among the 11-12 year olds. (3) LD children’s perspective-taking and verbal retelling competence were significantly lower than those of non-LD group. For polite request strategy, the influence of social perspective-taking to strategy application was indirect and must be via strategy comprehension, while for indirect reply strategy, strategy comprehension was found to play as a partial mediator between social perspective-taking and strategy application. The influence of verbal retelling to strategy application was indirect on both types of strategies. (4) LD children’s strategy comprehension and social perspective-taking level can be improved, and the improvement of these two competences has significant positive impact on the increase of their strategy application level. Key Words: learning disabilities, verbal communication strategy, social perspective- taking
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One of the most important functions in the individual development is the interaction and integration of each sensory input. There exist two competing theories, i.e. the deficiency theory and the compensatory theory, regarding the origin and nature of changes in visual functions observed after auditory deprivation. The deficiency theory proposed that integrative processes are essential for normal development. In contrast, the compensatory theory stated that the loss of one sense may be met by a greater reliance upon, therefore an enhancement of the remaining senses. Given that hearing impaired children’s learning depends primarily on visual information, it is important to recognize the differences of visual attention between them and their hearing age-mates. Differences among age groups could exist in either selectivity or sustained attention. Study 1 and study 2 explored the selective and sustained attention development of hearing impaired and hearing students with average cognitive ability, aged from 7 years to college students. The analysis and discussion of the results are based on the visual attention development as well as deficiency theory and compensatory theory. According to the results of the study 1 and study 2, the spatial distribution and controlling of the visual attention between hearing impaired and hearing students were also investigated in the study 3 and study 4. The present work showed that: Firstly, both hearing impaired and hearing participants had the similar developmental trajectory of the sustained attention. The ability of children’s sustained attention appeared to improve with age, and in adolescence it reached the peak. The hearing impaired participants had the comparable sustained attention skills to the matched hearing ones. Besides, the results of the hearing impaired participants showed that they could maintain their attention and vigilance on the current task over the observation period. Secondly, group differences of visual attention development were found between hearing impaired and hearing participants. In the childhood, the visual attention developmental speed of the hearing impaired children was slower than that of the hearing ones. The selective attention skill of the hearing impaired were not comparable to the hearing ones, however, their selective skill improved with age, so in the adulthood, hearing impaired students showed the slight advantage in the selective attention skill over the hearing ones. Thirdly, hearing impaired and hearing participants showed the similar spatial distribution in the attention resources. In the low perceptual load condition, both participants were suffered great interference of the distrator at the fixation. In contrast, in the high perceptual load condition, hearing impaired adults were suffered more interference of the peripheral distractor, which suggested that they distributed more attention resources to the peripheral field when faced difficult tasks. Fourthly, both groups showed similar processing in the visual attention tasks. That is, they both searched the target with only the color feature in a parallel way, but in a serial way while processing orientation feature and the features with the combination of the color and orientation. Furthermore, the results indicated that two groups show similar ways in the attention controlling. In summary, the present study showed that visual attention development was dependent upon the integration of multimodal sensory information. Because of the interaction and integration of the input from various sensory, it has a negative impact on the intact sensory at the early stage of one sensory loss, however, it can better the functions of other intact sensory gradually with development and practice.
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Reading is an important human-specific skill obtained through extensive learning experience and is reliance on the ability to rapidly recognize single words. According to the behavioral studies, the most important stage of reading is the representation of “visual word form”, which is independent on surface visual features of the reading materials. The prelexical visual word form representation is characterized by the abstractive and highly effective and precise processing. Neuroimaging and neuropsychological studies have investigated the neural basis underlying the visual word form processing. On the basis of summary of the existing literature, the current thesis aimed to address three fundamental questions involving neural basis of word recognition. First, is there a dedicated neural network that is specialized for word recognition? Second, is the orthographic information represented in the putative word/character selective region (VWFA)? Third, what is the role of reading experience in the genesis of the VWFA, is experience a main driver to shape VWFA instead of evolutionary selectivity? Nineteen Chinese literate volunteers, 5 Chinese illiterates and 4 native English speakers participated in this study, and performed perceptual tasks during fMRI scanning. To address the first question, we compared the differential responses to three categories of visual objects, i.e., faces, line drawings of objects and Chinese characters, and defined the region of interesting (ROI) for the next experiment. To address the second question, Chinese character orthography was manipulated to reveal possible differential responses to real characters, false characters, radical combinations, and stroke combinations in the regions defined by the first experiment. To examine the role of reading experience in genesis of specialization for character, the responses for unfamiliar Chinese characters in Chinese illiterates and native English speakers were compared with that in the Chinese literates, and tracked the change in cortical activation after a short-term reading training in the illiterates. Data were analyzed in two dimensions. Both BOLD signal amplitude and spatial distribution pattern among multi-voxels were used to systematically investigate the responsiveness of the left fusiform gyrus to Chinese characters. Our results provide strong and clear evidence for the existence of functionally specialized regions in the human ventral occipital-temporal cortex. In the skilled readers a region specialized for written words could be consistently found in the lateral part of the left fusiform gyrus, line drawings in the median part and faces in the middle. Our results further show that spatial distribution analysis, a method that was not commonly used in neuroimaging of reading, appears to be a more effective measurement for category specialization for visual objects processing. Although we failed to provide evidence that VWFA processes orthographic information in terms of signal intensitiy, we do show that response pattern of real characters and radical collections in this area is different from that of false characters and random stroke combinations. Our last set of experiments suggests that the selective bias to reading material is clearly experience dependent. The response to unknown characters in both English speakers/readers and Chinese illiterates is fundamentally different from that of the skilled Chinese readers. The response pattern for unknown characters is more similar to that for line drawings rather as a weak version of character in skilled Chinese readers. Short-term training is not sufficient to produce VWFA bias even when tested with learned characters, rather the learned characters generated a overall upward shift of the activation of the left fusiform region. Formation of a dedicated region specialized for visual word/character might depend on long-term extensive reading experience, or there might be a critical period for reading acquisition.
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The present cross-sectional study paid attention to Chinese reading acquisition of 391 children from preschool to grade 3 in two elementary schools, and investigated the relationship between orthographic processing skills, morphological awareness, phonological awareness, naming, phonological memory, visual processing skill and reading skills, after controlling the variance of age, nonverbal intelligence and pinyin knowledge. The main results are as follows: Firstly, there are many different language skills as the predictors of Chinese reading success. Orthographic processing skills, morphological awareness, phonological awareness and naming are important in single-character recognition and comprehension. Beside them, the effect of visual processing skill and phonological memory for comprehension are also significant. Among them, the role of orthographic processing skills is the most important, whatever in single-character recognition or in comprehension. Secondly, orthographic processing skills are the most important factors in reading acquisition at low grade and its effect drops obviously after grade 2. Thirdly, morphological awareness is also the factor that cannot be ignored whatever for single-character recognition or for comprehension. Its influence appears in preschool and becomes the only significant predictor of character recognition in grade 3. Furthermore, morphological awareness is more relevant with the development of comprehension. Fourthly, phonological awareness plays the secondary role in Chinese reading acquisition except in grade 2 when its contribution is most of all. And compare with morphological awareness, the effect of phonological awareness is relative low. Fifthly, naming is important through preschool to grade 2. The contribution of phonological memory increases from preschool to grade 3 in comprehension.
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Stimulus-Response Compatibility is a key concept in human-machine interaction. It is proved that to map stimulus to response according to salient-feature coding principle will get a compatible pair. In the designing of Chinese Pinyin Code inputting devices, stimulus-response compatibility will bring the device with features of ease of use and ease of learning. In this research, Response time and error rates of two designs of salient-feature coding principle and one design of random mapping were tested along with the QWERTY keyboard. Cross-modal Compatibility Effects were found, and no significant difference between two salient-feature coding types, both on response time and error rates; but response time has shown difference between salient-feature coding designs and random mapping design. Compared with the QWERTY keyboard group, the error rates of subjects of chord keyboard group showed no significant differences. But subjects assigned to the QWERTY keyboard group have a shorter response time. One possible reason is the subjects of chord keyboard group only at beginner skill after at most 6 hours practice whereas subjects of QWERTY group were at least at novice level after take a foundation of computer class at their own college.