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Search Results: 1 - 10 of 17 matches for " Asser ElGindy "
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Minefield Mapping Using Cooperative Multirobot Systems
Alaa Khamis,Asser ElGindy
Journal of Robotics , 2012, DOI: 10.1155/2012/698046
Abstract:
Minefield Mapping Using Cooperative Multirobot Systems
Alaa Khamis,Asser ElGindy
Journal of Robotics , 2012, DOI: 10.1155/2012/698046
Abstract: This paper presents a team-theoretic approach to cooperative multirobot systems. The individual actions of the robots are controlled by the Belief-Desire-Intention model to endow the robots with the know-how needed to execute these actions deliberately. The cooperative behaviors between the heterogeneous robots are governed by the Team-Log theory to endow all the robots in the team with the know-how-to-cooperate and determine the team members’ commitments to each other despite their different types, properties, and goals. The proposed approach is tested for validity with the real life problem of minefield mapping. Different minefield sweeping strategies are studied to control the mobility of the mobile sweepers within the minefield in order to maximize the area coverage and improve picture compilation capability of the multirobot system. 1. Introduction Developing a robust and cooperative team of robots capable of solving complex tasks is an interesting area of research that attracts many researchers nowadays. Achieving robust and productive cooperation between various system components is inspired by different domains such as biology, artificial life, psychology, and cognitive science in order to build artificially cooperative intelligent systems. Cooperation is defined in [1] as a purposive positive interference of agents to further the achievement of a common goal or goals compatible with their own. To achieve this effective cooperation in multirobot systems (MRS), the robots must have know-how for solving simple problems in an autonomous way and a know-how-to-cooperate by which agents can share common interests and interact with each other to solve complex problems cooperatively. In recent years, scientific community has seen a great number of research works dedicated to cooperative multirobot systems and their applications in different areas such as search and rescue [2, 3], distributed surveillance [4], communication relaying [5], agriculture [6], sorting [7], emergency services [8], and landmine detection [9]. Minefield reconnaissance and mapping is one of the most promising applications of cooperative multirobot systems. In the context of humanitarian demining, cooperative multirobot systems can be beneficial for deminers, civilians, and government. The design of an accurate sensor may reduce the amount of time needed to determine whether a landmine exists, but does not increase the safety of the deminer. Since the safety issues during the eradication process are of great concern, the use and integration of cheap and simple mobile sweepers in
High-Order Numerical Solution of Second-Order One-Dimensional Hyperbolic Telegraph Equation Using a Shifted Gegenbauer Pseudospectral Method
Kareem T. Elgindy
Mathematics , 2015,
Abstract: We present a high-order shifted Gegenbauer pseudospectral method (SGPM) to solve numerically the second-order one-dimensional hyperbolic telegraph equation provided with some initial and Dirichlet boundary conditions. The framework of the numerical scheme involves the recast of the problem into its integral formulation followed by its discretization into a system of well-conditioned linear algebraic equations. The integral operators are numerically approximated using some novel shifted Gegenbauer operational matrices of integration. We derive the error formula of the associated numerical quadratures. We also present a method to optimize the constructed operational matrix of integration by minimizing the associated quadrature error in some optimality sense. We study the error bounds and convergence of the optimal shifted Gegenbauer operational matrix of integration. Moreover, we construct the relation between the operational matrices of integration of the shifted Gegenbauer polynomials and standard Gegenbauer polynomials. We derive the global collocation matrix of the SGPM, and construct an efficient computational algorithm for the solution of the collocation equations. We present a study on the computational cost of the developed computational algorithm, and a rigorous convergence and error analysis of the introduced method. Four numerical test examples have been carried out in order to verify the effectiveness, the accuracy, and the exponential convergence of the method. The SGPM is a robust technique, which can be extended to solve a wide range of problems arising in numerous applications.
Validation of an Estonian version of the Parkinson's Disease Questionnaire (PDQ-39)
ülle Krikmann, Pille Taba, Taavi Lai, Toomas Asser
Health and Quality of Life Outcomes , 2008, DOI: 10.1186/1477-7525-6-23
Abstract: Study subjects were approached during their regular clinic follow-up visits. 104 patients consented to the study and 81 completed questionnaires were used for subsequent testing of psychometric characteristics, validity and reliability.The content validity was assessed through qualitative content analysis during the pilot study. The patients indicated that the questions were relevant to measure the quality of life of people with PD.The analysis of means showed that the ceiling and floor effects of domain results were within the limits of 15% of Summary Index and of all domains except Stigma, Social Support and Communication where the ceiling effect was 16% to 24% of the responses. Convergent validity was interpreted through correlation between disease severity and PDQ-39 domains. There was a statistically significant difference between the domain scores in patients with mild versus moderate PD in domains of Mobility, ADL, and Communication but not for Stigma, Social Support and Cognition. The reliability was good, Cronbach alpha for all domains and summary index was over 0.8 and item-test correlations between domains and summary index ranged from 0.56 to 0.83.The psychometric characteristics of an Estonian version of the PDQ-39 were satisfactory. The results of this study were comparable to the results of previous validation studies in other cultural settings in UK, USA, Canada, Spain and Italy.The Estonian version of the PDQ-39 is an acceptable, valid and reliable instrument for quality of life measurement in PD patients.Parkinson's disease (PD) is a progressive neurodegenerative disorder, characterised by bradykinesia, tremor, disturbances of postural reflexes and of the autonomic nervous system, and which is most prevalent in old age [1-3].Diagnosis and management of PD is based on clinical assessment of symptoms and signs using disease specific rating scales [4,5]. Evaluation of disease severity, effect of treatment procedures and interventions are all influence
Phosphodiesterase inhibition mediates matrix metalloproteinase activity and the level of collagen degradation fragments in a liver fibrosis ex vivo rat model
Sanne Skovg?rd Veidal, Mette Juul Nielsen, Diana Julie Leeming, Morten Asser Karsdal
BMC Research Notes , 2012, DOI: 10.1186/1756-0500-5-686
Abstract: In vivo: Rats were treated for 8?weeks with CCl4/Intralipid. Liver slices were cultured for 48?hours. Levels of C3M were determined in the supernatants of slices cultured without treatment, treated with GM6001 (positive control) or treated with IBMX (phosphodiesterase inhibitor). Enzymatic activity of MMP-2 and MMP-9 were studied by gelatin zymography. Ex vivo: The levels of serum C3M increased 77% in the CCl4-treated rats at week 8 (p?<?0.01); Levels of C3M increased significantly by 100% in fibrotic liver slices compared to controls after 48?hrs (p?<?0.01). By adding GM6001 or IBMX to the media, C3M was restored to control levels. Gelatin zymography demonstrated CCl4-treated animals had highly increased MMP-9, but not MMP-2 activity, compared to slices derived from control animals.We have combined an ex vivo model of liver fibrosis with measurement of a biochemical marker of collagen degradation in the condition medium. This technology may be used to evaluate the molecular process leading to structural fibrotic changes, as collagen species are the predominant structural part of fibrosis. These data suggest that modulation of cAMP may play a role in regulation of collagen degradation associated with liver fibrosis.Liver fibrosis due to viral or alcohol-induced injury is one of the leading causes of death worldwide [1]. Liver biopsy is the most commonly used method for fibrosis assessment, but it is invasive, associated with patient discomfort and, in rare cases, with serious complications [2-4]. Therefore, research has focused on the evaluation of non-invasive methods for the assessment of liver fibrosis [5], including a highly enforced effort in discovering and developing biochemical markers for liver fibrosis assessment. In alignment there is an urgent need for applied translational science, in which information from preclinical settings may be translated to clinical settings. One such approach may be to investigate the same biochemical analyte in liver explants
Family caregiver quality of life in multiple sclerosis among Kuwaitis: a controlled study
Asmahan F Alshubaili, Jude U Ohaeri, Abdel W Awadalla, Asser A Mabrouk
BMC Health Services Research , 2008, DOI: 10.1186/1472-6963-8-206
Abstract: Consecutive MS clinic attendees were assessed with the 26 – item WHOQOL Instrument, and for depression and disability. Similarly, caregivers independently rated their own QOL as well as their impression of patients' QOL and attitudes to patients' illness.The 170 caregivers, mean age 35.7 years, had no significant diagnostic differences in QOL domain scores and attitudes to MS. Caregivers had significantly lower QOL than the general population control group for five out of six domains and the general facet (P < 0.01), but higher QOL than the patients. When the scores were corrected for patients' depression and disability, caregivers had similar QOL with the general population group for four domains. Using corrected scores, MS caregivers had lower scores than diabetic and psychiatric caregivers in the physical, psychological and social relations domains. Majority expressed negative attitudes to MS. Caregiver QOL was more affected by their fear of having MS than their feelings about the illness and caregiving role. Caregiver attitudes had mostly no significant impact on their proxy ratings of patients' QOL. The significant predictor of caregivers' overall QOL was their impression of patients' QOL.Caregivers need specific attention if they are less educated, unemployed, afraid of having MS and caring for patients with longer duration of illness and less education. In particular, attention to patients' depression and disability could improve caregivers' QOL. Caregivers need specific programs to address fear of having MS, negative attitudes to illness and their unmet needs.Research interest in the quality of life (QOL) of persons with multiple sclerosis (MS) has been spurred by the need to broaden outcome measures to include factors that might indicate less obvious disease burdens [1,2]. Far less of this interest has been directed at the family caregivers [1,3]. It is important to study the impact of caregiving on families because MS places substantial burdens on patients
Relationship of depression, disability, and family caregiver attitudes to the quality of life of Kuwaiti persons with multiple sclerosis: a controlled study
Asmahan F Alshubaili, Abdel W Awadalla, Jude U Ohaeri, Asser A Mabrouk
BMC Neurology , 2007, DOI: 10.1186/1471-2377-7-31
Abstract: Consecutive clinic attendees at the national neurology hospital were assessed with the 26 -item WHOQOL Instrument, Beck's Depression Inventory and Expanded Disability Scale. Caregivers rated their impression of patients' QOL and attitudes to patients' illness.The 170 patients (60 m, 109 f) consisted of 145(85.3%) with RRMS and 25 with PMS, aged 32.4(SD 8.8), age at onset 27.1(7.7), EDSS score 2.9 (1.8), and 76% were employed. The patients were predominantly dissatisfied with their life circumstances. The RRMS group had higher QOL domain scores (P < 0.001), and lower depression(P > 0.05) and disability (P < 0.0001) scores than the PMS group. Patients had significantly lower QOL scores than the control group (P < 0.001). Caregiver impression was significantly correlated with patients' ratings. Depression was the commonest significant covariate of QOL domains. When we controlled for depression and disability scores, differences between the two MS groups became significant for only one (out of 6) QOL domains. Patients who were younger, better educated, employed, felt less sick and with lesser side effects, had higher QOL. The predictors of patients' overall QOL were disability score, caregiver impression of patients' QOL, and caregiver fear of having MS.Our data indicate that MS patients in stable condition and with social support can hope to have better QOL, if clinicians pay attention to depression, disability, the impact of side effects of treatment and family caregiver anxieties about the illness. The findings call for a regular program of psychosocial intervention in the clinical setting, to address these issues and provide caregiver education and supports, in order to enhance the quality of care.Multiple sclerosis (MS) is a chronic debilitating disease, arising from inflammation and demyelination of nerves in the central nervous system, characterized by remissions and relapses, affecting mostly young people and resulting in various degrees of physical and social d
Bioinformatic Approaches Reveal Metagenomic Characterization of Soil Microbial Community
Zhuofei Xu, Martin Asser Hansen, Lars H. Hansen, Samuel Jacquiod, S?ren J. S?rensen
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0093445
Abstract: As is well known, soil is a complex ecosystem harboring the most prokaryotic biodiversity on the Earth. In recent years, the advent of high-throughput sequencing techniques has greatly facilitated the progress of soil ecological studies. However, how to effectively understand the underlying biological features of large-scale sequencing data is a new challenge. In the present study, we used 33 publicly available metagenomes from diverse soil sites (i.e. grassland, forest soil, desert, Arctic soil, and mangrove sediment) and integrated some state-of-the-art computational tools to explore the phylogenetic and functional characterizations of the microbial communities in soil. Microbial composition and metabolic potential in soils were comprehensively illustrated at the metagenomic level. A spectrum of metagenomic biomarkers containing 46 taxa and 33 metabolic modules were detected to be significantly differential that could be used as indicators to distinguish at least one of five soil communities. The co-occurrence associations between complex microbial compositions and functions were inferred by network-based approaches. Our results together with the established bioinformatic pipelines should provide a foundation for future research into the relation between soil biodiversity and ecosystem function.
The Inhibitory Effect of Salmon Calcitonin on Tri-Iodothyronine Induction of Early Hypertrophy in Articular Cartilage
Pingping Chen-An, Kim Vietz Andreassen, Kim Henriksen, Yadong Li, Morten Asser Karsdal, Anne-Christine Bay-Jensen
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0040081
Abstract: Objective Salmon calcitonin has chondroprotective effect both in vitro and in vivo, and is therefore being tested as a candidate drug for cartilage degenerative diseases. Recent studies have indicated that different chondrocyte phenotypes may express the calcitonin receptor (CTR) differentially. We tested for the presence of the CTR in chondrocytes from tri-iodothyronin (T3)-induced bovine articular cartilage explants. Moreover, investigated the effects of human and salmon calcitonin on the explants. Methods Early chondrocyte hypertrophy was induced in bovine articular cartilage explants by stimulation over four days with 20 ng/mL T3. The degree of hypertrophy was investigated by molecular markers of hypertrophy (ALP, IHH, COLX and MMP13), by biochemical markers of cartilage turnover (C2M, P2NP and AGNxII) and histology. The expression of the CTR was detected by qPCR and immunohistochemistry. T3-induced explants were treated with salmon or human calcitonin. Calcitonin down-stream signaling was measured by levels of cAMP, and by the molecular markers. Results Compared with untreated control explants, T3 induction increased expression of the hypertrophic markers (p<0.05), of cartilage turnover (p<0.05), and of CTR (p<0.01). Salmon, but not human, calcitonin induced cAMP release (p<0.001). Salmon calcitonin also inhibited expression of markers of hypertrophy and cartilage turnover (p<0.05). Conclusions T3 induced early hypertrophy of chondrocytes, which showed an elevated expression of the CTR and was thus a target for salmon calcitonin. Molecular marker levels indicated salmon, but not human, calcitonin protected the cartilage from hypertrophy. These results confirm that salmon calcitonin is able to modulate the CTR and thus have chondroprotective effects.
Hundreds of Circular Novel Plasmids and DNA Elements Identified in a Rat Cecum Metamobilome
Tue Sparholt J?rgensen, Zhuofei Xu, Martin Asser Hansen, S?ren Johannes S?rensen, Lars Hestbjerg Hansen
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0087924
Abstract: Metagenomic approaches are widespread in microbiological research, but so far, the knowledge on extrachromosomal DNA diversity and composition has largely remained dependant on cultivating host organisms. Even with the emergence of metagenomics, complete circular sequences are rarely identified, and have required manual curation. We propose a robust in silico procedure for identifying complete small plasmids in metagenomic datasets from whole genome shotgun sequencing. From one very pure and exhaustively sequenced metamobilome from rat cecum, we identified a total of 616 circular sequences, 160 of which were carrying a gene with plasmid replication domain. Further homology analyses indicated that the majority of these plasmid sequences are novel. We confirmed the circularity of the complete plasmid candidates using an inverse-type PCR approach on a subset of sequences with 95% success, confirming the existence and length of discrete sequences. The implication of these findings is a broadened understanding of the traits of circular elements in nature and the possibility of massive data mining in existing metagenomic datasets to discover novel pools of complete plasmids thus vastly expanding the current plasmid database.
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