675 research outputs found
Towards minimizing the energy of slack variables for binary classification
No full text20.09.13 KB. Ok to add to spiral, author says conference already available online.This paper presents a binary classification algorithm that is based on the minimization of the energy of slack variables, called the Mean Squared Slack (MSS). A novel kernel extension is proposed which includes the withholding of just a subset of input patterns that are misclassified during training. The later leads to a time and memory efficient system that converges in a few iterations. Two datasets are exploited for performance evaluation, namely the adult and the vertebral column dataset. Experimental results demonstrate the effectiveness of the proposed algorithm with respect to computation time and scalability. Accuracy is also high. In specific, it equals 84.951% for the adult dataset and 91.935%, for the vertebral column dataset, outperforming state-of-the-art methods. © 2012 EURASIP
On the slack phenomena and snap force in tethers of submerged floating tunnels under wave conditions
No full textUnder severe sea wave conditions, the mooring tethers of submerged floating tunnel (SFT) might go slack. It may cause the structure failure during the service lifetime of SFT. The paper investigated SFT dynamics when going through tether slacking and the related snap force under wave conditions. Besides the nonlinearity of fluid drag and of structural geometry for a relative large structure displacement, the problem is characterized by the nonlinearity due to the discontinuity in axial stiffness of the tethers. To include these nonlinearities, the method of Lagrange energy is used to build the governing equations of SFT motion, and a bilinear oscillator is introduced to simulate the mooring tether operating in an alternating slack-taut state. The sensitivities of the occurrence of tether slacking to wave height and wave period are investigated. Results show that at a large wave height SFT tether will go slack and snap force occurs. SFT responses are categorized into three types of state according to the dynamic response characteristics of tether tension. Effects of two fundamental structure parameters, buoyancy-weight ratio (BWR) and inclined mooring angle (IMA), on the dynamic responses of SFT are analyzed. A slack-taut map of SFT tethers is built. It intuitively describes the occurrences of slack and snap force with different combinations of the two parameters. An analytical approach for slack prediction by deriving the slack criterion is provided to reveal the mechanism of the presented slack-taut map. By present research, the authors tried to make their effort to provide an alternative philosophy for SFT structural design on concerning preventing the occurrence of tether slacking and snap force. (C) 2011 Elsevier Ltd. All rights reserved
Factors regulating sediment fluxes over an engineered foredune and adjacent dune slack
No full textThis study aims to identify and understand the annual scale sediment transport patterns in a fully engineered dune-dune slack system that was created from seabed sediments for grey dune and moist dune slack habitat creation at the Delfland coast (the Netherlands). The annual morphological development was analysed using LiDAR elevation data. Daily aeolian sediment transport was simulated across the foredune and in the adjacent dune slack, using the numerical aeolian sediment transport model AeoLiS. All simulated transport events were combined to reveal how aeolian sediment transport behaves on an annual scale. Planting two continuous strips of marram grass along the top of the foredune induced rapid growth of the foredune, while limiting sediment supply to the dune slack. The armouring layer of shells that formed at the surface of the engineered topography, functioned as a supply-limiting factor and restricted the sediment entrainment and deflation of the dune slack. Therefore, the formation of a moist dune slack habitat may take longer for this engineered case than in a natural case with similar boundary conditions
On the two essential concepts for SFT: synergetic buoyancy-weight ratio and slack-taut map
No full textIn the submerged floating tunnel (SFT) design and future construction, buoyancy-weight ratio (BWR) and slack-taut performance (STP) are two intrinsic issues with respect to the SFT dynamic response and stability under the structural and external loadings. BWR is defined as the ratio of tunnel buoyancy to the whole tunnel weight. Our experiments and numerical simulations indicate that BWR dominates the dynamic response of SFT and is the most important parameter to be considered in SFT design. For this, we re-state the essential concept of "Synergetic range of BWR". This is regarded as, for an SFT structure with related environmental conditions, a suitable range of BWR value exists, which will lead to less dynamic response and more stable for the SFT. STP is the tether slacking and the related snap force under sea wave conditions. Our simulation results show that SFT tether may go slack and induce snap force at a large wave height at a certain combination of BWR and inclined morning angle (IMA) of the tether. As the second essential concept for SFT, a Slack-Taut Map of SFT is constructed, which describes the occurrences of slack and snap force (under a certain wave condition) as a function of BWR and IMA. (C) 2016 The Authors. Published by Elsevier Ltd
Study of Sediment Transport in a Tidal Channel‐Shoal System: Lateral Effects and Slack‐Water Dynamics
No full textLateral flows redistribute sediment and influence the morphodynamics of channel-shoal systems. However, our understanding of lateral transport of suspended sediment during high and low water slack is still fairly limited, especially in engineered estuaries. Human interventions such as dike-groyne structures influence lateral exchange mechanisms. The present study aims to unravel these mechanisms in a heavily engineered, turbid channel-shoal system in the Changjiang Estuary, using a high-resolution unstructured-grid three-dimensional model and in situ observations. Analysis of model results reveals two typical transport patterns during slack-water conditions, that is, shoal-to-channel transport during low water slack and channel-to-shoal transport during high water slack. A momentum balance analysis is carried out to explain mechanisms driving the lateral transport of suspended sediment during high water slack, revealing the importance of lateral pressure gradients, Coriolis force, and the curvature-induced term. Groyne fields play a crucial role in sediment transport, especially during low water slack. A model scenario in which one groyne is removed reveals that groyne fields strongly influence lateral sediment transport. The decomposition of the sediment transport flux reveals that the turbidity maximum is shaped by a balance between seaward advection by residual flows, and landward transport by tidal pumping and gravitational circulation. Within the turbidity maximum, sediment is laterally redistributed by lateral flows during slack-water conditions, greatly influencing estuarine channel morphology.</p
The Effect of Budget Participation, Information Asymmetry, Budget Emphasis, and Organizational Commitment on Budgetary Slack: Pengaruh Partisipasi Anggaran, Asimetri Informasi, Budget Emphasis Dan Komitmen Organisasi Terhadap Budgetary Slack
No full textThis study aims to analyze the effect of budgetary participation, information asymmetry, budget emphasis, and organizational commitment on budgetary slack. The sampling technique used in this research is purposive sampling. the criteria determined by the author are the sample selected only by respondents related to the process of budget preparation, implementation and accountability. In this case, it is the activity program planning for each SKPD which consists of the head of the service, the secretary, the head of the finance sub-section. Based on the questionnaire criteria, 144 questionnaires were distributed (48 SKPD x 3 Respondents). This study uses multiple linear regression analysis techniques to test the hypothesis with the SPSS version 27 data processing tool. The results of this study indicate that budgetary participation has an effect on budgetary slack. Information Asymmetry Affects Budgetary Slack. Budget Emphasis Influences Budgetary Slack. Organizational Commitment Influences Budgetary Slack
A Role for Metabotropic Glutamate Receptors in Healthy Ageing
No full textThe proportion of older individuals globally is increasing. This results in an increase in socioeconomic costs as more people are living long enough to suffer from the detrimental effects of ageing such as chronic age-related diseases. Thus, there is an urgent need to understand the mechanisms that drive ageing and promote healthy ageing. Ageing research using simple model organisms has shown that ageing can be modulated by genetic and environmental factors and these interventions extend lifespan and improve health in evolutionarily distant organisms. In this thesis, the fruit fly, Drosophila melanogaster was used to study the role of metabotropic glutamate receptors (mGluR) in biological ageing. mGluRs are highly conserved G-protein coupled receptors activated by the amino acid, L-glutamate to modulate intracellular signal transduction cascades, including the PI3K and MAP/ERK signalling pathways which play evolutionary conserved roles in animal ageing. By utilising a null mutation of the gene encoding the single fly mGluR we have found that loss of mGluR activity in flies causes sex-specific differences on longevity. This sex-specific effect was found to be strain-specific and may be partly attributed to differences in DmGluRA mRNA levels. This study also aimed to elucidate the mechanism(s) by which loss of mGluR extends lifespan. Phenotyping studies revealed that the long-lived mutants were associated with several phenotypes including increased resistance to stress, body weight and differences in triglyceride usage under starvation conditions. The studies also appear to rule out some possible mechanisms for the lifespan extension associated with loss of mGluR in Drosophila such as dietary restriction and improvements in gut physiology. RNA-Seq analysis also identified several genes which change in expression as a response to loss of mGluR signalling, many of which may explain the phenotypes observed and so are potential mechanisms of longevity. Further studies are required to fully understand the mechanisms of lifespan extension but taken together, the results form a case for mGluR as a novel ageing regulator
The development of an autonomous GPS system to monitor tidal slack in estuaries
No full textRecently, a promising method for measuring tidal slack using GPS receivers attached to buoys has been tested. The next step is to build a wireless GPS system which conducts measurements continuous and real-time. This research primarily focuses on the development of the hardware of that GPS system. Secondly it focuses on modeling the buoy behavior and calculation algorithms for determining the moment of slack. A series of GPS measurements are conducted to test the accuracy and precision of candidate receivers. For the hardware a Waspmote-board and Meshlium router are chosen. Together they provide a complete solution for the GPS system, including GPS receiver. The solution combines adaptability with low costs. The module is made waterproof and solar powered. A buoy model is made with which data sets can be simulated to test the accuracy of the calculation algorithms. The sensitivity tests of the algorithms are performed with a Monte Carlo model. Clear differences in performance between high-end and common receivers are observed. EGNOS improves only the performance of the high-end receiver. The buoys have different behaviour, not all buoys can be modeled the same. Also a bias of up to 10 minutes is found for the calculation algorithms. In terms of sensitivity of the methods, there is a critical standard deviation for the GPS receiver for which the methods become unstable.With all tested GPS receivers the moment of tidal slack can be calculated with a deviation up to 15 minutes. The greatest improvement can be made in reducing the bias in the calculation methods.Water ResourcesWater ManagementCivil Engineering and Geoscience
Modulation of ageing by genetic knock-out, phototherapy and drugs in the C. elegans worm
No full textAssisting healthy ageing is a key goal of 21st century healthcare. Caenorhabditis elegans is an attractive model species for ageing studies because of its short life cycle (ca. 3 days), its rapid development, and the homology of its genome with that of humans. Clinical phenotypic studies indicated that different flavin-containing monooxygenase (FMO) and various diol compounds had a role in longevity extension in C. elegans. New, endogenous functions of FMOs in C. elegans were determined, including fmo-4, the loss of which resulted in significant phenotypic differences and enhanced lifespan, compared with wild type worms. Nuclear magnetic resonance (NMR) spectroscopy-based metabolite analyses of extracts of different C. elegans FMO mutants at different life stages and of diol-treated worms revealed biochemistry that correlated with genotype and influence on lifespan. Meanwhile, as seen in studies with higher model organisms, irradiation of C. elegans with 670 nm red light also increased ATP levels, improved mitochondrial dynamics and enhanced worm motility. Infra-red (1072 nm) exposure was already reported to increase C. elegans lifespan. The effects of the chemical, physical and genetic interventions on C. elegans provide clues about the mechanisms and possible strategies to extend healthy lifespan in human old age
Ras signaling in aging and metabolic regulation
No full textAberrant signal transduction downstream of the Ras GTPase has a well-established role in tumorigenesis. Mutations that result in hyperactivation of Ras are responsible for a third of all human cancers. Hence, small molecule inhibitors of the Ras signal transduction cascade have been under intense focus as potential cancer treatments. In both invertebrate and mammalian models, emerging evidence has also implicated components of the Ras signaling pathway in aging and metabolic regulation. Here, I review the current evidence for Ras signaling in these newly discovered roles highlighting the interactions between the Ras pathway and other longevity assurance mechanisms. Defining the role of Ras signaling in maintaining age-related health may have important implications for the development of interventions that could not only increase lifespan but also delay the onset and/or progression of age-related functional decline
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