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Paradoxical prosopagnosia in semantic dementia  [PDF]
Sven-Erik Fernaeus, Per Ostberg, Lars-Olof Wahlund, Nenad Bogdanovic
Advances in Alzheimer's Disease (AAD) , 2012, DOI: 10.4236/aad.2012.13008
Abstract: Objective: To study episodic and semantic memory for faces and other non-verbal information in semantic dementia (SD). Background: Semantic memory impaired in the rare diagnosis of SD by definition, including knowledge about well- known persons and their appearance. Episodic memory is held to be better preserved. Methods: Two computerized face recognition tests were administered, one measuring episodic memory (Male Faces) and one semantic memory (Political Faces) in addition to a comprehensive test battery. A computerised test of non-verbal semantic memory for national symbols (Euro Flags) was also administered druring the retention interval of the Male Faces test. Results: The SD participants were severely impaired in the episodic face recognition test. In contrast, their performance was in the normal range in Euro Flags and Political Faces, based on knowledge of national political figures. Conclusion: The results are discussed in terms of preserved dynamic memory and severely impaired memory for static facial information in semantic dementia. Research proposals regarding further studies of this paradoxical prosopagnosia in semantic dementia are presented in order to clarify issues regarding static versus dynamic aspects of face memory.
Primary progressive aphasia: A comparative study of progressive nonfluent aphasia and semantic dementia
George Annamma,Mathuranath P
Neurology India , 2005,
Abstract: Primary progressive aphasia (PPA), a degenerative disorder, is often misdiagnosed as Alzheimer′s disease. Its subtypes, semantic dementia (SD), and progressive nonfluent aphasia (PNFA), are often difficult to differentiate from each other. Our objective was to highlight the differences in the language profiles of patients with SD and PNFA. To bring out these differences, we report two patients with PPA, one with SD and the other with PNFA. They were administered the Western aphasia battery (WAB) and a semantic battery, which assesses semantic memory. The profiles of language impairment on the WAB indicated that the patient with PNFA had syntactic errors in expressive speech but relatively preserved semantics and comprehension, whereas the patient with SD had preserved syntax but made semantic errors in expressive speech, and had impaired comprehension. There were differences in their performance on the semantic battery too. The patient with SD made relatively less errors on confrontation naming, although on the pointing task he failed to point to those line drawings, which he was unable to name on confrontation. In contrast, the finding of the PNFA patient was the reverse of this. Supplementing conventional neuropsychological tests with formal tests for assessment of language functions is useful in the early diagnosis of PPA. The performance of PPA patients on a detailed assessment of language that includes use of formal tests such as the semantic battery helps to differentiate PNFA from SD.
Can Knowledge be preserved in the long run?  [PDF]
Rina Panigrahy
Computer Science , 2010,
Abstract: Can (scientific) knowledge be reliably preserved over the long term? We have today very efficient and reliable methods to encode, store and retrieve data in a storage medium that is fault tolerant against many types of failures. But does this guarantee -- or does it even seem likely -- that all knowledge can be preserved over thousands of years and beyond? History shows that many types of knowledge that were known before have been lost. We observe that the nature of stored and communicated information and the way it is interpreted is such that it always tends to decay and therefore must lost eventually in the long term. The likely fundamental conclusion is that knowledge cannot be reliably preserved indefinitely.
Making Memories: The Development of Long-Term Visual Knowledge in Children with Visual Agnosia  [PDF]
Tiziana Metitieri,Carmen Barba,Simona Pellacani,Maria Pia Viggiano,Renzo Guerrini
Neural Plasticity , 2013, DOI: 10.1155/2013/306432
Abstract: There are few reports about the effects of perinatal acquired brain lesions on the development of visual perception. These studies demonstrate nonseverely impaired visual-spatial abilities and preserved visual memory. Longitudinal data analyzing the effects of compromised perceptions on long-term visual knowledge in agnosics are limited to lesions having occurred in adulthood. The study of children with focal lesions of the visual pathways provides a unique opportunity to assess the development of visual memory when perceptual input is degraded. We assessed visual recognition and visual memory in three children with lesions to the visual cortex having occurred in early infancy. We then explored the time course of visual memory impairment in two of them at 2?years and 3.7?years from the initial assessment. All children exhibited apperceptive visual agnosia and visual memory impairment. We observed a longitudinal improvement of visual memory modulated by the structural properties of objects. Our findings indicate that processing of degraded perceptions from birth results in impoverished memories. The dynamic interaction between perception and memory during development might modulate the long-term construction of visual representations, resulting in less severe impairment. 1. Introduction Visual agnosia is a modality-specific disorder of object recognition caused by a lesion involving the visual cortex [1]. As originally described by Lissauer [2] the disorder cannot be attributed to poor sensory processing, and recognition of objects through other modalities can be relatively preserved. Most of our understanding of visual agnosia derives from investigations of adults with visual agnosia acquired after years of normal functioning [3]. Previous findings suggest that long-term memory and recognition can be concurrently or differentially impaired [1]. In the majority of cases of agnosia both memory and perception are clearly impaired [4], though, in some, the representations stored in memory are preserved even for objects that cannot be recognized [5–7]. However, data from agnosics exploring the dynamic influence of degraded perceptions on the updating of long-term visual knowledge are limited. The longitudinal investigation of the profoundly agnosic H.J.A. demonstrated a subtle deterioration in his ability to draw objects from memory over time [8]. These data might suggest an interplay between perception and memory rather than their functional independence [8]: when perceptual processing is impaired, visual memory may gradually decline, due to less
Semantic Integration of Knowledge Management Systems  [cached]
Napoleon - Alexandru Sireteanu,Constantin Florin S?rbu
Communications of the IBIMA , 2008,
Abstract: Ontologies are essential for a semantic integration of knowledge components which can be seen as superior pieces of intellectual capital. Knowledge structures connect individual or group knowledge elements from organizational knowledge bases that have been developed independently. This can aid search and navigation for the entire organizational knowledge base. As many knowledge processes cross boundaries of organizational units or of whole organizations, standardization of techniques for representing knowledge structures (Semantic Web technologies), play an important role in enabling organizations to share documented knowledge.
Representation of Knowledge patterns for Semantic Web  [PDF]
Rostislav Miarka
International Journal of Computer Science Issues , 2013,
Abstract: This article presents representation of knowledge patterns in RDF language. The approach to knowledge representation can be used in Semantic Web as a tool of finding some additional RDF assertions in the frame of linked data. The article introduces the term knowledge pattern" and dividing the knowledge patterns into two groups - to Top-level knowledge patterns and to Domain knowledge patterns. Examples of top-level knowledge patterns for sentences in the English language are also a part of this article.
Towards Semantic Knowledge Mapping: An Extension of Compendium with Semantic Knowledge Representation  [PDF]
Krishna Sapkota,Arantza Aldea,Rene Banares-Alcantara
International Journal of Artificial Intelligence & Applications , 2012,
Abstract: Compendium is a knowledge mapping application equipped with graphical representations of ideas andarguments. Extension of the processes in Compendium with Semantic Web technologies can be beneficialfor the intelligent searching of concepts or ideas, and supporting decision making process. This paperpresents the extended Compendium which exploits the Semantic Web for knowledge representation anduser interaction. The result evaluated by the experts and users showed that the extension eases andstreamlines the decision making process.
Semantic Knowledge Influences Prewired Hedonic Responses to Odors  [PDF]
Johan Poncelet,Fanny Rinck,Anne Ziessel,Pauline Joussain,Marc Thévenet,Catherine Rouby,Moustafa Bensafi
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0013878
Abstract: Odor hedonic perception relies on decoding the physicochemical properties of odorant molecules and can be influenced in humans by semantic knowledge. The effect of semantic knowledge on such prewired hedonic processing over the life span has remained unclear.
Context Tricks for Cheap Semantic Segmentation  [PDF]
Thanapong Intharah,Gabriel J. Brostow
Computer Science , 2015,
Abstract: Accurate semantic labeling of image pixels is difficult because intra-class variability is often greater than inter-class variability. In turn, fast semantic segmentation is hard because accurate models are usually too complicated to also run quickly at test-time. Our experience with building and running semantic segmentation systems has also shown a reasonably obvious bottleneck on model complexity, imposed by small training datasets. We therefore propose two simple complementary strategies that leverage context to give better semantic segmentation, while scaling up or down to train on different-sized datasets. As easy modifications for existing semantic segmentation algorithms, we introduce Decorrelated Semantic Texton Forests, and the Context Sensitive Image Level Prior. The proposed modifications are tested using a Semantic Texton Forest (STF) system, and the modifications are validated on two standard benchmark datasets, MSRC-21 and PascalVOC-2010. In Python based comparisons, our system is insignificantly slower than STF at test-time, yet produces superior semantic segmentations overall, with just push-button training.
THE ROLE OF THE SEMANTIC WEB IN STRUCTURING ORGANIZATIONAL KNOWLEDGE  [PDF]
Mangiuc Dragos Marian
Annals of the University of Oradea : Economic Science , 2009,
Abstract: The present paper is a component of an exploratory research project focused on discovering new ways to build, organize and consolidate organizational memory for an economic entity by means of the new a€ Semantic Weba€ technologies and also encloses some
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