10,246 research outputs found

    Controlling Chaos in a Neural Network Based on the Phase Space Constraint

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    The chaotic neural network constructed with chaotic neurons exhibits very rich dynamic behaviors and has a nonperiodic associative memory. In the chaotic neural network, however, it is dicult to distinguish the stored patters from others, because the states of output of the network are in chaos. In order to apply the nonperiodic associative memory into information search and pattern identication, etc, it is necessary to control chaos in this chaotic neural network. In this paper, the phase space constraint method focused on the chaotic neural network is proposed. By analyzing the orbital of the network in phase space, we chose a part of states to be disturbed. In this way, the evolutional spaces of the strange attractors are constrained. The computer simulation proves that the chaos in the chaotic neural network can be controlled with above method and the network can converge in one of its stored patterns or their reverses which has the smallest Hamming distance with the initial state of the network. The work claries the application prospect of the associative dynamics of the chaotic neural network

    A Type of Delay Feedback Control of Chaotic Dynamics in a Chaotic Neural Network

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    A chaotic neural network consisting of chaotic neurons exhibits such rich dynamical behaviors as nonperiodic associative memory. But it is difficult to distinguish the stored patterns from others, since the chaotic neural network shows chaotic wandering around the stored patterns. In order to apply the nonperiodic associative memory to information search or pattern identification, it is necessary to control chaotic dynamics. In this paper, we propose a delay feedback control method for the chaotic neural network. Computer simulation shows that, by means of the control method, the chaotic dynamics in the chaotic neural network are changed. The output sequence of the controlled network wanders around one stored pattern and its reverse pattern

    Post-AGB Stars in Globular Clusters and Galactic Halos

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    We discuss three aspects of post-AGB (PAGB) stars in old populations. (1) HST photometry of the nucleus of the planetary nebula (PN) K 648 in the globular cluster (GC) M15 implies a mass of 0.60 Msun, in contrast to the mean masses of white dwarfs in GCs of ~0.5 Msun. This suggests that K 648 is descended from a merged binary, and we infer that single Pop II stars do not produce visible PNe. (2) Yellow PAGB stars are the visually brightest stars in old populations (Mv ~ -3.3) and are easily recognizable because of their large Balmer jumps; thus they show great promise as a Pop II standard candle. Two yellow PAGB stars in the GC NGC 5986 have the same V magnitudes to within +/-0.05 mag, supporting an expected narrow luminosity function. (3) Using CCD photometry and a u filter lying below the Balmer jump, we have detected yellow PAGB stars in the halo of M31 and in its dwarf elliptical companion NGC 205. With the Milky Way zero point, we reproduce the Cepheid distance to M31, and find that NGC 205 is ~100 kpc further away than M31. The star counts imply a yellow PAGB lifetime of about 25,000 yr, and their luminosities imply masses near 0.53 Msun.Comment: 6 pages, 2 figures. To appear in proceedings of Torun, Poland, workshop on "Post-AGB Objects (Proto-Planetary Nebulae) as a Phase of Stellar Evolution," ed. S.K. Gorn

    Controlling chaos in a chaotic neural network

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    The chaotic neural network constructed with chaotic neuron shows the associative memory function, but its memory searching process cannot be stabilized in a stored state because of the chaotic motion of the network. In this paper, a pinning control method focused on the chaotic neural network is proposed. The computer simulation proves that the chaos in the chaotic neural network can be controlled with this method and the states of the network can converge in one of its stored patterns if the control strength and the pinning density are chosen suitable. It is found that in general the threshold of the control strength of a controlled network is smaller at higher pinned density and the chaos of the chaotic neural network can be controlled more easily if the pinning control is added to the variant neurons between the initial pattern and the target pattern

    Ritucharya as Preventive Medicine

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    Introduction: Ayurveda the age old science of life, has always emphasized at maintaining health and preventing diseases rather than laying total focus over the treatment aspects. It has highlighted various rules and regimens regarding Ahara (diet), Vihara (regimens), Achara (conduct) and Vichara (thoughts) which are mandatory for attaining the desired healthy life. One among such regimens is “Ritucharya”, which plays an important role in acclimatizing the seasonal enforcement easily without altering body homeostasis. Purpose: Ritu (season), classified by variation of Doshas in the environment, expresses its effects on the body, hence disturbing its equilibrium (Prakruthi-Purusha Samyata Siddantha), this disequilibrium occurs due to failure in following the appropriate rules which leads to imbalance among Doshas in the body and thereafter leading to disease manifestation. Hence there arises a need to understand and implement these guidelines in accordance with the changes in Ritu. Methods: In this study Ayurveda elementary books were thoroughly searched where the concept of Ritucharya has been described and comprehended simultaneously. Result/Discussion: In this work an attempt is made to understand various concepts evolving around Ritucharya including: 1) Scientific background of Ritu 2) Seasonal regimens and diet 3) Prevention of seasonal diseases through Ritucharya 4) Increased morbidity during Ritusandi and its prevention 5) Ritu Vaiparyata and corresponding modifications. Conclusion: Although the concept of Ritucharya seems very simple, but it is crucial for balancing the constitutional entities as per seasonal changes. These guidelines thus become very important for maintaining a disease free body-mind, thus reducing morbidity to various seasonal disorders and improving one’s immunity

    Examining the Use of Social Media in Customer Co-Creation: A Blog Mining Study

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    Social media have been used by some companies to support customer co-creation in recent years. However, few academic studies have been done to investigate the use of social media for customer co-creation. To understand the current state-of-the-art and future trends about the use of social media for customer co-creation, we conducted a blog mining study to analyze relevant posts on blogs. This blog study reveals some interesting patterns, themes and future trends in this specific area

    Does angiotensin-1 converting enzyme genotype influence motor or cognitive development after pre-term birth?

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    BACKGROUND: Raised activity of the renin-angiotensin system (RAS) may both amplify inflammatory and free radical responses and decrease tissue metabolic efficiency and thus enhance cerebral injury in the preterm infant. The angiotensin-converting enzyme (ACE) DD genotype is associated with raised ACE and RAS activity as well as potentially adverse stimuli such as inflammation. The DD genotype has been associated with neurological impairments in the elderly, and thus may be also associated with poorer motor or cognitive development amongst children born preterm prematurely. METHODS: The association of DD genotype with developmental progress amongst 176 Caucasian children born at less than 33 weeks gestation (median birthweight 1475 g, range 645–2480 g; gestation 30 weeks, range 22–32; 108 male) was examined at 2 and 5 1/2 years of age. Measured neuro-cognitive outcomes were cranial ultrasound abnormalities, cerebral palsy, disability, Griffiths Developmental Quotient [DQ] at 2 yrs, and General Cognitive Ability [British Ability Scales-11] and motor performance [ABC Movement], both performed at 5 1/2 yrs. All outcomes were correlated with ACE genotype. RESULTS: The DD genotype was not associated with lower developmental quotients even after accounting for important social variables. CONCLUSION: These data do not support either a role for ACE in the development of cognitive or motor function in surviving infants born preterm or inhibition of ACE as a neuroprotective therapy

    Pandemic Pedagogy in Online Hands-on Learning for IT/IS Courses

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    Due to the coronavirus disease of 2019 (COVID-19) pandemic, many educational institutions have transitioned to online instruction. As a result, instructors need to investigate online small group learning opportunities to bond with their students who feel isolated from their peers due to social-distancing guidelines. In this paper, we discuss three key issues in online hands-on learning: 1) interactions, 2) equity and inclusive participation, and 3) students’ readiness for hands-on or higher-level cognitive learning. We reflect on our teaching experience during the COVID-19 pandemic and offer suggestions to help instructors plan and implement online small group hands-on learning
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