753 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
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
Dynamic simulation of a multi-cable driven parallel suspension platform with slack cables
No full textIn this paper, a modelling method and an accurate numerical procedure are presented to simulate the dynamical responses of a multi-cable driven parallel suspension platform system. For such systems, the cables might become slack due to external excitations and due to the fact that cables can become tensionless when been pushed in longitudinal direction. In lateral and torsional directions, the constraint forces between the cables and platform can be positive as well as negative. This paper will deal with the non-smooth cable vibrations (in longitudinal, lateral and torsional directions) by taking into account the slackness of the cables. Firstly, the Lagrange equation with constraints is used to derive the equations of motion of the multi-cable suspension platform. Then, by expressing the equations of motion and constraint equations at velocity level, a non-smooth algorithm is used to numerically solve the equations. Finally, the numerical results are compared with an ADAMS simulation, and the two results agree well with each other. Moreover, the results in this paper significantly improve the numerical results used in the analysis of the dynamics for multi-cable systems which usually neglect the lateral properties of the cables.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Mathematical Physic
Untangling the multiple effects of slack resources on firms’ exporting behavior
No full textThis is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Drawing on a behavioral theory perspective, we investigate how distinct types of slack resources affect distinct aspects of firms’ exporting behavior. Using longitudinal data of Belgian manufacturing firms, we find that financial and human resource (HR) slack affect the probability of exporting positively at a diminishing rate. Controlling for the export decision, we find that HR slack affects export intensity negatively, while financial and HR slack affect export diversity positively at a diminishing rate. Findings are economically meaningful, especially for new exporters. Taken together, our study adds new insights at the nexus of the international business and slack literatures.Research Foundation - Flander
Rice growing farmers efficiency measurement using a slack based interval DEA model with undesirable outputs
No full textIn recent years eco-efficiency which considers the effect of production process on environment in determining the efficiency of firms have gained traction and a lot of attention. Rice farming is one of such production processes which typically produces two types of outputs which are economic desirable as well as environmentally undesirable. In efficiency analysis, these undesirable outputs cannot be ignored and need to be included in the model to obtain the actual estimation of firm’s efficiency. There are numerous approaches that have been used in data envelopment analysis (DEA) literature to account for undesirable outputs of which directional distance function (DDF) approach is the most widely used as it allows for simultaneous increase in desirable outputs and reduction of undesirable outputs. Additionally, slack based DDF DEA approaches considers the output shortfalls and input excess in determining efficiency. In situations when data uncertainty is present, the deterministic DEA model is not suitable to be used as the effects of uncertain data will not be considered. In this case, it has been found that interval data approach is suitable to account for data uncertainty as it is much simpler to model and need less information regarding the underlying data distribution and membership function. The proposed model uses an enhanced DEA model which is based on DDF approach and incorporates slack based measure to determine efficiency in the presence of undesirable factors and data uncertainty. Interval data approach was used to estimate the values of inputs, undesirable outputs and desirable outputs. Two separate slack based interval DEA models were constructed for optimistic and pessimistic scenarios. The developed model was used to determine rice farmers efficiency from Kepala Batas, Kedah. The obtained results were later compared to the results obtained using a deterministic DDF DEA model. The study found that 15 out of 30 farmers are efficient in all cases. It is also found that the average efficiency values of all farmers for deterministic case is always lower than the optimistic scenario and higher than pessimistic scenario. The results confirm with the hypothesis since farmers who operates in optimistic scenario are in best production situation compared to pessimistic scenario in which they operate in worst production situation. The results show that the proposed model can be applied when data uncertainty is present in the production environmen
- …
