ABSTRACT The effects of aerodynamic model assumptions on the optimal wing-kinematics for hovering... more ABSTRACT The effects of aerodynamic model assumptions on the optimal wing-kinematics for hovering micro-air-vehicles are determined. Specific kinematic functions for the wing motion are specified and the parameters of these functions are considered as the design variables for the optimization problem. Four aerodynamic models having different levels of fidelity that capture various physical aspects of hovering aerodynamics are considered to assess the effects of these different aspects on the optimal wing kinematics. These physical aspects include the leading edge vortex, rotational lift, non-circulatory contributions, and flow unsteadiness. Conventional models for pitching wings are not adequate as they predict considerably high rotational lift and too little power requirements, which makes the optimizer, unrealistically, leans toward almost pure rotational motion with little flapping. In addition, quasi-steady modeling overestimates the generated lift and, as such, leads to a more optimal, but unrealistic, performance. Therefore efficient unsteady modeling is essential in design optimization of flapping-wing micro-air-vehicles.
The current study examined how morpho-orthographic knowledge affects the orthographic preferences... more The current study examined how morpho-orthographic knowledge affects the orthographic preferences among typical and poor native Arab readers. Two-hundred participants (100 typical and 100 poor readers) from second to sixth grade were tested using pseudo-orthographic choice task, which was composed from fifty pairs of homophonic pseudowords. For each pair of homophonic pseudowords, the participants were asked to circle the one that appears acceptable as real word according to its written orthographic pattern. The results revealed that the accuracy levels among typical readers were significantly higher than those of poor readers. Among the typical group of readers, older participants showed higher accuracy levels than younger readers, while this pattern of performance was not shown among the poor readers, indicating that morpho-orthographic knowledge which affect the spelling and orthographic preferences in Arabic is a result of intact reading development.
This paper discusses a mini-experiment; an exercise was devised to investigate the effects of rep... more This paper discusses a mini-experiment; an exercise was devised to investigate the effects of repeated articulation on the acquisition of syntax. The main participants of the experiment are two Hebrewspeaking students, one formally assessed as having reading disabilities, one female age 14 (Q) and one dyslexic male age 16 (W). Q has been learning English at school for 4 years; she is in eighth grade. She is in the group for weak learners of English and does not show signs of a reading disability. She has taken private tuition once a week for approximately 5 months. She had not previously studied the target structure in the experiment. The results are discussed in light of the literature review findings, and some applied implications and conclusions were drawn for learning disabilities (LD) teaching.
Gender differences in Arabic spelling accuracy of 288 Arabic speaking students from grade 1 to gr... more Gender differences in Arabic spelling accuracy of 288 Arabic speaking students from grade 1 to grade 9 were assessed. The spelling errors of these students were analyzed according to the paradigm of Abu- . The results showed that generally across all ages/grades girls made fewer spelling errors, especially in the phonological and semiphonological spelling errors categories. The results are discussed in light of the international language research findings. ______________
The Arabic alphabetical orthographic system has various unique features that include the existenc... more The Arabic alphabetical orthographic system has various unique features that include the existence of emphatic phonemic letters. These represent several pairs of letters that share a phonological similarity and use the same parts of the articulation system. The phonological and articulatory similarities between these letters lead to spelling errors where the subject tends to produce a pseudohomophone (PHw) instead of the correct word. Here, we investigated whether or not the unique orthographic features of the written Arabic words modulate early orthographic processes. For this purpose, we analyzed event-related potentials (ERPs) collected from adult skilled readers during an orthographic decision task on real words and their corresponding PHw. The subjects' reaction times (RTs) were faster in words than in PHw. ERPs analysis revealed significant response differences between words and the PHw starting during the N170 and extending to the P2 component, with no difference during processing steps devoted to phonological and lexico-semantic processing. Amplitude and latency differences were found also during the P6 component which peaked earlier for words and where source localization indicated the involvement of the classical left language areas. Our findings replicate some of the previous findings on PHw processing and extend them to involve early orthographical processes.
Previous research has suggested that reading Arabic is more challenging than reading Hebrew or En... more Previous research has suggested that reading Arabic is more challenging than reading Hebrew or English, even among native Arabic readers due to the visual complexity of the Arabic orthography. In particular, the fact that most of the Arabic letters connect to each other and change their basic form according to their place in the written word (beginning, middle or end) has been hypothesised to constitute a visual load affecting reading efficiency. Here, we tested this visual complexity hypothesis by manipulating word-internal orthographic connectivity during visual word recognition. Fifty-eight adult skilled readers and 20 disabled readers of Arabic performed a lexical-decision task using words (and nonwords) whose letters were naturally fully connected (Cw), partially connected (PCw) and nonconnected (NCw). Behavioural measures for words as a function of word connectivity (and word frequency) were analysed using repeated measures analysis of variance. The results revealed that within both groups of readers, higher accuracy rates were measured for the Cw rather than for the NCw, with PCw falling in between. The analysis of the individual standard deviations of the response times within each word condition revealed that Cw yielded a response variance lower than NCw, again with PCw in between. These results indicate that Cw tend to be processed more efficiently and accurately than NCw, in both reader groups. The results presented here extend recent findings in normal readers and indicate that word connectivity does not negatively
Reading and writing disabilities and generalized cognitive dysfunction are developmental in origi... more Reading and writing disabilities and generalized cognitive dysfunction are developmental in origin and are likely linked to abnormalities in brain function. In this article, we detail selective reading and writing disturbances in the spoken and written Arabic orthography of an Arab teenager (RL) who communicates with his friends via readable and understandable electronic messages. We examine the performance of RL, who was diagnosed as learning disabled, in his reading and writing of Arabic words and text in Latin orthography compared to his reading and writing in Arabic orthography. Cognitive and verbal abilities in Arabic and Latin electronic orthography were tested using traditional pen and paper as well as electronic devices. The results underline the importance of the effect of the type of Arabic orthography on reading and writing fluency.
The dominant error types were investigated as a function of phonological processing (PP) deficit ... more The dominant error types were investigated as a function of phonological processing (PP) deficit severity in four groups of impaired readers. For this aim, an error analysis paradigm distinguishing between four error types was used. The findings revealed that the different types of impaired readers were characterized by differing predominant error types. The dysphonetic errors predominated in readers with severe PP deficit and the morphological errors predominated in those with moderate deficits. Finally, readers with attention difficulties showed a predominance of semiphonetic errors. These findings were discussed in relation to reading disability subtypes and their clinical implications.
This study aimed at assessing the effects of letters' connectivity in Arabic on visual word recog... more This study aimed at assessing the effects of letters' connectivity in Arabic on visual word recognition. For this purpose, reaction times (RTs) and accuracy scores were collected from ninety-third, sixth and ninth grade native Arabic speakers during a lexical decision task, using fully connected (Cw), partially connected (PCw) and nonconnected (NCw) Arabic words and pseudowords. Effects of grade on word recognition (in RTs and accuracy) and word superiority were predicted to occur. Also, in the third grade, recognition of NCw was predicted to be faster and more accurate than recognition of Cw, because in previous studies NCw were assumed to be visually less complex. In sixth and ninth grades, due to the frequent exposure to connected forms, the recognition of Cw was predicted to be as fast as or faster and more accurate than NCw. The findings largely supported the first and the second hypotheses. As for the third graders, a mixed pattern was obtained, suggesting that the participants were probably in a transitional phase. The results from sixth graders clearly showed that NCw yielded the slowest response times and the lowest accuracy scores across connectivity conditions. Finally, for Electronic supplementary material The online version of this article (ninth graders, the absence of connectivity effects on the speed of processing was attributed to the use of very frequent and highly automatized words.
Most of the spelling error analysis has been conducted in Latin orthographies and rarely conducte... more Most of the spelling error analysis has been conducted in Latin orthographies and rarely conducted in other orthographies like Arabic. Two hundred and eighty-eight students in grades 1-9 participated in the study. They were presented nine lists of words to test their spelling skills. Their spelling errors were analyzed by error categories. The most frequent errors were phonological. The results did not indicate any significant differences in the percentages of phonological errors across grades one to nine. Thus, phonology probably presents the greatest challenge to students developing spelling skills in Arabic.
One of the unique features of the Arabic orthography that differentiates it from many other alpha... more One of the unique features of the Arabic orthography that differentiates it from many other alphabetical ones is the fact that most letters connect obligatorily to each other. Hence, these letters change their forms according to the location in the word (i.e. beginning, middle, or end), leading to the suggestion that connectivity adds a visual load which negatively impacts reading in Arabic. In this study, we investigated the effects of the orthographic connectivity on the time course of early brain electric responses during the visual word recognition. For this purpose, we collected event-related potentials (ERPs) from adult skilled readers while performing a lexical decision task using fully connected (Cw), partially connected and nonconnected words (NCw). Reaction times variance was higher and accuracy was lower in NCw compared to Cw words. ERPs analysis revealed significant amplitude and latency differences between Cw and NCw at posterior electrodes during the N170 component which implied the temporo-occipital areas. Our findings show that instead of slowing down reading, orthographic connectivity in Arabic skilled readers seems to impact positively the reading process already during the early stages of word recognition.
Journal of psycholinguistic research, Jan 28, 2015
The current study investigated the contribution of two linguistic intervention programs, phonolog... more The current study investigated the contribution of two linguistic intervention programs, phonological and morphological to the development of word spelling among skilled and poor native Arabic readers, in three grades: second, fourth and sixth. The participants were assigned to three experimental groups: morphological intervention, phonological intervention and a non-intervention control group. Phonological awareness, morphological awareness, and spelling abilities were tested before and after the intervention. Participants from both linguistic intervention programs and in all grades made significant progress in linguistic awareness and spelling after the intervention. The results showed that both intervention programs were successful in promoting children's spelling skills in both groups. Also, older poor readers showed a stronger response to the morphological intervention than the older skilled readers. A transfer effect was found with the phonological training contributing to...
This study aimed to examine the effects of visual characteristics of Arabic orthography on learni... more This study aimed to examine the effects of visual characteristics of Arabic orthography on learning to read compared to Hebrew among Arabic and Hebrew bilinguals in an elementary bilingual education framework. Speed and accuracy measures were examined in reading words and non-words in Arabic and Hebrew as follows: Arabic words and non-words composed of connected and similar letters, words and non-words composed of connected and non-similar letters, and words and non-words composed of unconnected letters. In Hebrew, words and non-words composed of similar letters and non-similar letters. It was found that Arabic speakers showed an almost equal control in all reading tasks in both languages whereas, Hebrew speakers showed better performance in their mother tongue in all reading tasks. In Arabic, the best performance was in reading words and non-words that was unconnected. Based on these findings, it was concluded that Hebrew speakers did not succeed in transferring their good ability ...
ABSTRACT The effects of aerodynamic model assumptions on the optimal wing-kinematics for hovering... more ABSTRACT The effects of aerodynamic model assumptions on the optimal wing-kinematics for hovering micro-air-vehicles are determined. Specific kinematic functions for the wing motion are specified and the parameters of these functions are considered as the design variables for the optimization problem. Four aerodynamic models having different levels of fidelity that capture various physical aspects of hovering aerodynamics are considered to assess the effects of these different aspects on the optimal wing kinematics. These physical aspects include the leading edge vortex, rotational lift, non-circulatory contributions, and flow unsteadiness. Conventional models for pitching wings are not adequate as they predict considerably high rotational lift and too little power requirements, which makes the optimizer, unrealistically, leans toward almost pure rotational motion with little flapping. In addition, quasi-steady modeling overestimates the generated lift and, as such, leads to a more optimal, but unrealistic, performance. Therefore efficient unsteady modeling is essential in design optimization of flapping-wing micro-air-vehicles.
The current study examined how morpho-orthographic knowledge affects the orthographic preferences... more The current study examined how morpho-orthographic knowledge affects the orthographic preferences among typical and poor native Arab readers. Two-hundred participants (100 typical and 100 poor readers) from second to sixth grade were tested using pseudo-orthographic choice task, which was composed from fifty pairs of homophonic pseudowords. For each pair of homophonic pseudowords, the participants were asked to circle the one that appears acceptable as real word according to its written orthographic pattern. The results revealed that the accuracy levels among typical readers were significantly higher than those of poor readers. Among the typical group of readers, older participants showed higher accuracy levels than younger readers, while this pattern of performance was not shown among the poor readers, indicating that morpho-orthographic knowledge which affect the spelling and orthographic preferences in Arabic is a result of intact reading development.
This paper discusses a mini-experiment; an exercise was devised to investigate the effects of rep... more This paper discusses a mini-experiment; an exercise was devised to investigate the effects of repeated articulation on the acquisition of syntax. The main participants of the experiment are two Hebrewspeaking students, one formally assessed as having reading disabilities, one female age 14 (Q) and one dyslexic male age 16 (W). Q has been learning English at school for 4 years; she is in eighth grade. She is in the group for weak learners of English and does not show signs of a reading disability. She has taken private tuition once a week for approximately 5 months. She had not previously studied the target structure in the experiment. The results are discussed in light of the literature review findings, and some applied implications and conclusions were drawn for learning disabilities (LD) teaching.
Gender differences in Arabic spelling accuracy of 288 Arabic speaking students from grade 1 to gr... more Gender differences in Arabic spelling accuracy of 288 Arabic speaking students from grade 1 to grade 9 were assessed. The spelling errors of these students were analyzed according to the paradigm of Abu- . The results showed that generally across all ages/grades girls made fewer spelling errors, especially in the phonological and semiphonological spelling errors categories. The results are discussed in light of the international language research findings. ______________
The Arabic alphabetical orthographic system has various unique features that include the existenc... more The Arabic alphabetical orthographic system has various unique features that include the existence of emphatic phonemic letters. These represent several pairs of letters that share a phonological similarity and use the same parts of the articulation system. The phonological and articulatory similarities between these letters lead to spelling errors where the subject tends to produce a pseudohomophone (PHw) instead of the correct word. Here, we investigated whether or not the unique orthographic features of the written Arabic words modulate early orthographic processes. For this purpose, we analyzed event-related potentials (ERPs) collected from adult skilled readers during an orthographic decision task on real words and their corresponding PHw. The subjects' reaction times (RTs) were faster in words than in PHw. ERPs analysis revealed significant response differences between words and the PHw starting during the N170 and extending to the P2 component, with no difference during processing steps devoted to phonological and lexico-semantic processing. Amplitude and latency differences were found also during the P6 component which peaked earlier for words and where source localization indicated the involvement of the classical left language areas. Our findings replicate some of the previous findings on PHw processing and extend them to involve early orthographical processes.
Previous research has suggested that reading Arabic is more challenging than reading Hebrew or En... more Previous research has suggested that reading Arabic is more challenging than reading Hebrew or English, even among native Arabic readers due to the visual complexity of the Arabic orthography. In particular, the fact that most of the Arabic letters connect to each other and change their basic form according to their place in the written word (beginning, middle or end) has been hypothesised to constitute a visual load affecting reading efficiency. Here, we tested this visual complexity hypothesis by manipulating word-internal orthographic connectivity during visual word recognition. Fifty-eight adult skilled readers and 20 disabled readers of Arabic performed a lexical-decision task using words (and nonwords) whose letters were naturally fully connected (Cw), partially connected (PCw) and nonconnected (NCw). Behavioural measures for words as a function of word connectivity (and word frequency) were analysed using repeated measures analysis of variance. The results revealed that within both groups of readers, higher accuracy rates were measured for the Cw rather than for the NCw, with PCw falling in between. The analysis of the individual standard deviations of the response times within each word condition revealed that Cw yielded a response variance lower than NCw, again with PCw in between. These results indicate that Cw tend to be processed more efficiently and accurately than NCw, in both reader groups. The results presented here extend recent findings in normal readers and indicate that word connectivity does not negatively
Reading and writing disabilities and generalized cognitive dysfunction are developmental in origi... more Reading and writing disabilities and generalized cognitive dysfunction are developmental in origin and are likely linked to abnormalities in brain function. In this article, we detail selective reading and writing disturbances in the spoken and written Arabic orthography of an Arab teenager (RL) who communicates with his friends via readable and understandable electronic messages. We examine the performance of RL, who was diagnosed as learning disabled, in his reading and writing of Arabic words and text in Latin orthography compared to his reading and writing in Arabic orthography. Cognitive and verbal abilities in Arabic and Latin electronic orthography were tested using traditional pen and paper as well as electronic devices. The results underline the importance of the effect of the type of Arabic orthography on reading and writing fluency.
The dominant error types were investigated as a function of phonological processing (PP) deficit ... more The dominant error types were investigated as a function of phonological processing (PP) deficit severity in four groups of impaired readers. For this aim, an error analysis paradigm distinguishing between four error types was used. The findings revealed that the different types of impaired readers were characterized by differing predominant error types. The dysphonetic errors predominated in readers with severe PP deficit and the morphological errors predominated in those with moderate deficits. Finally, readers with attention difficulties showed a predominance of semiphonetic errors. These findings were discussed in relation to reading disability subtypes and their clinical implications.
This study aimed at assessing the effects of letters' connectivity in Arabic on visual word recog... more This study aimed at assessing the effects of letters' connectivity in Arabic on visual word recognition. For this purpose, reaction times (RTs) and accuracy scores were collected from ninety-third, sixth and ninth grade native Arabic speakers during a lexical decision task, using fully connected (Cw), partially connected (PCw) and nonconnected (NCw) Arabic words and pseudowords. Effects of grade on word recognition (in RTs and accuracy) and word superiority were predicted to occur. Also, in the third grade, recognition of NCw was predicted to be faster and more accurate than recognition of Cw, because in previous studies NCw were assumed to be visually less complex. In sixth and ninth grades, due to the frequent exposure to connected forms, the recognition of Cw was predicted to be as fast as or faster and more accurate than NCw. The findings largely supported the first and the second hypotheses. As for the third graders, a mixed pattern was obtained, suggesting that the participants were probably in a transitional phase. The results from sixth graders clearly showed that NCw yielded the slowest response times and the lowest accuracy scores across connectivity conditions. Finally, for Electronic supplementary material The online version of this article (ninth graders, the absence of connectivity effects on the speed of processing was attributed to the use of very frequent and highly automatized words.
Most of the spelling error analysis has been conducted in Latin orthographies and rarely conducte... more Most of the spelling error analysis has been conducted in Latin orthographies and rarely conducted in other orthographies like Arabic. Two hundred and eighty-eight students in grades 1-9 participated in the study. They were presented nine lists of words to test their spelling skills. Their spelling errors were analyzed by error categories. The most frequent errors were phonological. The results did not indicate any significant differences in the percentages of phonological errors across grades one to nine. Thus, phonology probably presents the greatest challenge to students developing spelling skills in Arabic.
One of the unique features of the Arabic orthography that differentiates it from many other alpha... more One of the unique features of the Arabic orthography that differentiates it from many other alphabetical ones is the fact that most letters connect obligatorily to each other. Hence, these letters change their forms according to the location in the word (i.e. beginning, middle, or end), leading to the suggestion that connectivity adds a visual load which negatively impacts reading in Arabic. In this study, we investigated the effects of the orthographic connectivity on the time course of early brain electric responses during the visual word recognition. For this purpose, we collected event-related potentials (ERPs) from adult skilled readers while performing a lexical decision task using fully connected (Cw), partially connected and nonconnected words (NCw). Reaction times variance was higher and accuracy was lower in NCw compared to Cw words. ERPs analysis revealed significant amplitude and latency differences between Cw and NCw at posterior electrodes during the N170 component which implied the temporo-occipital areas. Our findings show that instead of slowing down reading, orthographic connectivity in Arabic skilled readers seems to impact positively the reading process already during the early stages of word recognition.
Journal of psycholinguistic research, Jan 28, 2015
The current study investigated the contribution of two linguistic intervention programs, phonolog... more The current study investigated the contribution of two linguistic intervention programs, phonological and morphological to the development of word spelling among skilled and poor native Arabic readers, in three grades: second, fourth and sixth. The participants were assigned to three experimental groups: morphological intervention, phonological intervention and a non-intervention control group. Phonological awareness, morphological awareness, and spelling abilities were tested before and after the intervention. Participants from both linguistic intervention programs and in all grades made significant progress in linguistic awareness and spelling after the intervention. The results showed that both intervention programs were successful in promoting children's spelling skills in both groups. Also, older poor readers showed a stronger response to the morphological intervention than the older skilled readers. A transfer effect was found with the phonological training contributing to...
This study aimed to examine the effects of visual characteristics of Arabic orthography on learni... more This study aimed to examine the effects of visual characteristics of Arabic orthography on learning to read compared to Hebrew among Arabic and Hebrew bilinguals in an elementary bilingual education framework. Speed and accuracy measures were examined in reading words and non-words in Arabic and Hebrew as follows: Arabic words and non-words composed of connected and similar letters, words and non-words composed of connected and non-similar letters, and words and non-words composed of unconnected letters. In Hebrew, words and non-words composed of similar letters and non-similar letters. It was found that Arabic speakers showed an almost equal control in all reading tasks in both languages whereas, Hebrew speakers showed better performance in their mother tongue in all reading tasks. In Arabic, the best performance was in reading words and non-words that was unconnected. Based on these findings, it was concluded that Hebrew speakers did not succeed in transferring their good ability ...
Uploads
Papers by Haitham Taha