Intelligent feature based resource selection and process planning

Lien vers la version éditeur: https://www.inderscience.com/books/index.php?action=record&rec_id=755&chapNum=3&journalID=1022&year=2010This paper presents an intelligent knowledge-based integrated manufacturing system using the STEP feature-based modeling and rule based intelligent techniques to generate suitable process plans for prismatic parts. The system carries out several stages of process planning, such as identification of the pairs of feature/tool that satisfy the required conditions, generation of the possible process plans from identified tools/machine pairs, and selection of the most interesting process plans considering the economical or timing indicators. The suitable processes plans are selected according to the acceptable range of quality, time and cost factors. Each process plan is represented in the tree format by the information items corresponding to their CNC Machine, required tools characteristics, times (machining, setup, preparatory) and the required machining sequences. The process simulation module is provided to demonstrate the different sequences of machining. After selection of suitable process plan, the G-code language used by CNC machines is generated automatically. This approach is validated through a case

Representation and Interaction of Sensorimotor Learning Processes

Human sensorimotor control is remarkably adept at utilising contextual information to learn and recall systematic sensorimotor transformations. Here, we investigate the motor representations that underlie such learning, and examine how motor memories acquired based on different contextual information interact. Using a novel three-dimensional robotic manipulandum, the 3BOT, we examined the spatial transfer of learning across various movement directions in a 3D environment, while human subjects performed reaching movements under velocity-dependent force field. The obtained pattern of generalisation suggested that the representation of dynamic learning was most likely defined in a target-based, rather than an extrinsic, coordinate system. We further examined how motor memories interact when subjects adapt to force fields applied in orthogonal dimensions. We found that, unlike opposing fields, learning two spatially orthogonal force fields led to the formation of separate motor memories, which neither interfered with nor facilitated each other. Moreover, we demonstrated a novel, more general aspect of the spontaneous recovery phenomenon using a two-dimensional force field task: when subjects learned two orthogonal force fields consecutively, in the following phase of clamped error feedback, the expression of adaptation spontaneously rotated from the direction of the second force field, towards the direction of the first force field. Finally, we examined the interaction of sensorimotor memories formed based on separate contextual information. Subjects performed reciprocating reaching and object manipulation tasks under two alternating contexts (movement directions), while we manipulated the dynamics of the task in each context separately. The results suggested that separate motor memories were formed for the dynamics of the task in different contexts, and that these motor memories interacted by sharing error signals to enhance learning. Importantly, the extent of interaction was not fixed between the context-dependent motor memories, but adaptively changed according to the task dynamics to potentially improve overall performance. Together, our experimental and theoretical results add to the understanding of mechanisms that underlie sensorimotor learning, and the way these mechanisms interact under various tasks and different dynamics.The thesis was funded by Wellcome Trust and the Yousef Jameel scholarship via Cambridge Trust

A Study on Clustering for Clustering Based Image De-Noising

In this paper, the problem of de-noising of an image contaminated with Additive White Gaussian Noise (AWGN) is studied. This subject is an open problem in signal processing for more than 50 years. Local methods suggested in recent years, have obtained better results than global methods. However by more intelligent training in such a way that first, important data is more effective for training, second, clustering in such way that training blocks lie in low-rank subspaces, we can design a dictionary applicable for image de-noising and obtain results near the state of the art local methods. In the present paper, we suggest a method based on global clustering of image constructing blocks. As the type of clustering plays an important role in clustering-based de-noising methods, we address two questions about the clustering. The first, which parts of the data should be considered for clustering? and the second, what data clustering method is suitable for de-noising.? Then clustering is exploited to learn an over complete dictionary. By obtaining sparse decomposition of the noisy image blocks in terms of the dictionary atoms, the de-noised version is achieved. In addition to our framework, 7 popular dictionary learning methods are simulated and compared. The results are compared based on two major factors: (1) de-noising performance and (2) execution time. Experimental results show that our dictionary learning framework outperforms its competitors in terms of both factors.Comment: 9 pages, 8 figures, Journal of Information Systems and Telecommunications (JIST

Antioxidant activity of Trifolium resupinatum L. exposed to different extracts from leaves, flowers and shoots of Prangos ferulacea

Prangos ferulacea is a member of Apiaceae family, is a popular fodder for livestock production and an important species in rangeland restoration. The objectives of the research are the comparative phytotoxic activity of aqueous and hydroalcoholic extracts obtained from different organs (flower, shoot and leaf) of P. ferulacea on antioxidant response of Trifolium resupinatum was investigated in a laboratory bioassay. Antioxidant enzyme activities including catalase (CAT), peroxidase (POD), ascorbic peroxidase (APX), and superoxide dismutase (SOD), in line with content of malondialdehyde (MDA) and hydrogen peroxide were measured. Results indicated that hydroalcoholic extract of P. ferulaceae flower possess the highest total phenolic content as well as highest phytotoxic effect on T. resupinatum. The highest antioxidant enzyme activity belonged to hydroalcoholic treatment. The treated T. resupinatum seedlings experienced lipid peroxidation at high extract concentrations (12% of hydroalcoholic and 100% of aqueous extract) as evidenced by increased concentration of MDA. In response to this, the activities of SOD, CAT, POD and APX increased at lower extract concentrations but significantly dropped as concentrations increased. According to results of this study, rehabilitation of T. resupinatum sites through the use of P. ferulaceae will probably not be successful

Sensitive Determination of Terazosin in Pharmaceutical Formulations and Biological Samples by Ionic-Liquid Microextraction Prior to Spectrofluorimetry

An efficient and environmentally friendly sample preparation method based on the application of hydrophobic 1-Hexylpyridinium hexafluorophosphate [Hpy][PF6] ionic liquid (IL) as a microextraction solvent was proposed to preconcentrate terazosin. The performance of the microextraction method was improved by introducing a common ion of pyridinium IL into the sample solution. Due to the presence of the common ion, the solubility of IL significantly decreased. As a result, the phase separation successfully occurred even at high ionic strength, and the volume of the settled IL-phase was not influenced by variations in the ionic strength (up to 30% w/v). After preconcentration step, the enriched phase was introduced to the spectrofluorimeter for the determination of terazosin. The obtained results revealed that this system did not suffer from the limitations of that in conventional ionic-liquid microextraction. Under optimum experimental conditions, the proposed method provided a limit of detection (LOD) of 0.027 μg L−1 and a relative standard deviation (R.S.D.) of 2.4%. The present method was successfully applied to terazosin determination in actual pharmaceutical formulations and biological samples. Considering the large variety of ionic liquids, the proposed microextraction method earns many merits, and will present a wide application in the future

Linkage of modules over Cohen-Macaulay rings

Inspired by the works in linkage theory of ideals, the concept of sliding depth of extension modules is defined to prove the Cohen-Macaulyness of linked module if the base ring is merely Cohen-Macaulay. Some relations between this new condition and other module-theory conditions such as G-dimension and sequentially Cohen-Macaulay are established. By the way several already known theorems in linkage theory are improved or recovered by new approaches.Comment: 12 Page

Improved genetic algorithms by means of fuzzy crossover operators for revenue management in airlines

Abstract: Revenue Management is an economic policy that increases the earned profit by adjusting the service demand and inventory. Revenue Management in airlines correlates with inventory control and price levels in different fare classes. We focus on pricing and seat allocation problems in airlines by introducing a constrained optimization problem in Binary Integer Programming (BIP) formulation. Two BIP problems are represented. Moreover, some improved Genetic Algorithms (GAs) approaches are used to solve these problems. We introduce new crossover operators that assign a Fuzzy Membership Function to each parent in GAs. We achieve better outputs with new methods that take lower calculation times and earn higher profits. Three different test problems in different scales are selected to evaluate the effectiveness of each algorithm. This paper defines new crossover operators that help to reach better solutions that take lower calculation times and more earned profits

Investigando o efeito destrutivo do terremoto em paisagens urbanas (estudo de caso: Ahar City)

This research has been conducted to determine the vulnerability of Ahar city spaces due to geographical location and other influential conditions. Using the results of previous researches and presenting combinational components and the modern indexes using the AHP model, this issue has been addressed and, finally, the output of data has been provided. In general, the results of the vulnerability analysis of the spaces of Ahar town indicate that most of the constructed parts of the city are in the moderate vulnerability area; marginal settlements are in the area of high vulnerability and central and historical parts are classified in the area of highly vulnerable zones. However, in the zoning of the whole city’s vulnerability, which includes built and arid spaces, the city is placed in the very low vulnerable classification. Accordingly, preventing the unauthorized separation and construction in marginal neighborhoods, the construction of neighborhood parks, the construction and completion of the main road network, the preparing restoration and renovation projects of worn-out and marginal textures, prevention the unauthorized separation outside the legal boundaries of the city, the transformation of abandoned cemeteries into public spaces such as the green space and cultural spaces, wall-laying and channeling of the rivers and river sides and dredging and updating them, are priorities of planning and implementation to rehabilitate the city of Ahar in response to the earthquake.Esta pesquisa foi realizada para determinar a vulnerabilidade dos espaços da cidade de Ahar devido à localização geográfica e outras condições influentes. Usando os resultados de pesquisas anteriores e apresentando componentes combinacionais e os índices modernos usando o modelo AHP, esta questão foi abordada e, finalmente, a saída de dados foi fornecida. Em geral, os resultados da análise de vulnerabilidade dos espaços da cidade de Ahar indicam que a maioria das partes construídas da cidade está na área de vulnerabilidade moderada; assentamentos marginais estão na área de alta vulnerabilidade e partes centrais e históricas são classificadas na área de zonas altamente vulneráveis. No entanto, no zoneamento da vulnerabilidade de toda a cidade, que inclui espaços construídos e áridos, a cidade é colocada na classificação muito baixa e vulnerável. Assim, impedir a separação e construção não autorizadas em bairros marginais, a construção de parques de bairro, a construção e conclusão da rede rodoviária principal, a preparação de projetos de restauração e renovação de texturas desgastadas e marginais, impedir a separação não autorizada fora dos limites legais da cidade, a transformação de cemitérios abandonados em espaços públicos como o espaço verde e espaços culturais, colocação de muro e canalização dos rios e fluviais e dragagem e sua atualização, são prioridades de planejamento e implantação para reabilitar a cidade de Ahar em resposta ao terremoto.Esta pesquisa foi realizada para determinar a vulnerabilidade dos espaços da cidade de Ahar devido à localização geográfica e outras condições influentes. Usando os resultados de pesquisas anteriores e apresentando componentes combinacionais e os índices modernos usando o modelo AHP, esta questão foi abordada e, finalmente, a saída de dados foi fornecida. Em geral, os resultados da análise de vulnerabilidade dos espaços da cidade de Ahar indicam que a maioria das partes construídas da cidade está na área de vulnerabilidade moderada; assentamentos marginais estão na área de alta vulnerabilidade e partes centrais e históricas são classificadas na área de zonas altamente vulneráveis. No entanto, no zoneamento da vulnerabilidade de toda a cidade, que inclui espaços construídos e áridos, a cidade é colocada na classificação muito baixa e vulnerável. Assim, impedir a separação e construção não autorizadas em bairros marginais, a construção de parques de bairro, a construção e conclusão da rede rodoviária principal, a preparação de projetos de restauração e renovação de texturas desgastadas e marginais, impedir a separação não autorizada fora dos limites legais da cidade, a transformação de cemitérios abandonados em espaços públicos como o espaço verde e espaços culturais, colocação de muro e canalização dos rios e fluviais e dragagem e sua atualização, são prioridades de planejamento e implantação para reabilitar a cidade de Ahar em resposta ao terremoto