837 research outputs found

    Thirty years of heterogeneous vehicle routing

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    It has been around thirty years since the heterogeneous vehicle routing problem was introduced, and significant progress has since been made on this problem and its variants. The aim of this survey paper is to classify and review the literature on heterogeneous vehicle routing problems. The paper also presents a comparative analysis of the metaheuristic algorithms that have been proposed for these problems

    Budd-chiari syndrome and renal arterial neurysms due to behcet disease: a rare association

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    Behcet’s disease is a multisystemic vasculitis of unknown etiology with a chronic relapsing course. Vasculitis in Behcet’s disease with predominant vascular involvement is the only vasculitis that affects both arteries and veins of any size. Involvement of the renal artery and inferior vena cava is rare among the arteries and veins, respectively. When disease affect the veins, it is in the form of thrombosis. Arterial complications include  aneurysms, stenosis and occlusions. Both rupture of arterial aneurysm and occlusion of suprahepatic veins,  causing Budd-Chiari syndrome, are associated with a high mortality rate. Vascular involvement is more common in male patients than in female patients. Men and patients with a younger age of onset present with a more severe prognosis. In this case report, we describe a very rare cause of intrarenal arterial aneurysm’s rupture with  previous Budd-Chiari syndrome due to Behcet’s disease and successful angiographic embolization of actively bleeding aneurysm

    Analytical Solutions of Klein-Gordon Equation with Position-Dependent Mass for q-Parameter Poschl-Teller potential

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    The energy eigenvalues and the corresponding eigenfunctions of the one-dimensional Klein-Gordon equation with q-parameter Poschl-Teller potential are analytically obtained within the position-dependent mass formalism. The parametric generalization of the Nikiforov-Uvarov method is used in the calculations by choosing a mass distribution.Comment: 10 page

    Coherent States for the Non-Linear Harmonic Oscillator

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    Wave packets for the Quantum Non-Linear Oscillator are considered in the Generalized Coherent State framerwork. To first order in the non-linearity parameter the Coherent State behaves very similarly to its classical counterpart. The position expectation value oscillates in a simple harmonic manner. The energy-momentum uncertainty relation is time independent as in a harmonic oscillator. Various features, (such as the Squeezed State nature), of the Coherent State have been discussed

    Potential algebra approach to position dependent mass Schroedinger equation

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    It is shown that for a class of position dependent mass Schroedinger equation the shape invariance condition is equivalent to a potential symmetry algebra. Explicit realization of such algebras have been obtained for some shape invariant potentials

    Prototype implementation of dynavote e-voting protocol

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    Voting is regarded as one of the most effective methods for individuals to express their opinions on a given topic. Electronic voting (eVoting) refers to the use of computers or computerised voting equipments to cast ballots in an election. eVoting performed over Internet can be universally accepted in the upcoming years due to the fact that Internet plays key roles in people's lives. The DynaVote eVoting protocol claims that it is practical over a network since it does not use complex algorithms and has no physical assumptions such as untappable channels, whereas fulfilling core voting requirements such as privacy, accuracy, uncoercibility and individual verifiability. Software development requires considerable amount of time and money. Therefore, in order to utilise all resources, the prototype implementation gains more importance as it gives quick feedbacks about the practicality of the system. This paper presents a prototype implementation of DynaVote eVoting protocol over the Internet. Since DynaVote relies on PVID scheme, which is an unlinkable pseudo identity mechanism, the prototype includes implementation of PVID scheme component as well. The main outcome of this study is to prove that DynaVote protocol over Internet is practical and applicable in real life and to illustrate that PVID scheme provides unlinkability. This study also contributes some improvements in DynaVote e-voting protocol. Furthermore, this paper analyses how the prototype fulfils some electronic voting system requirements such as efficiency, transparency and mobility

    Failure behavior of composite laminates under four-point bending

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    In this study, failure behavior of fiber-reinforced composites under four-point bending is investigated. First, the tests are modeled analytically using the classical lamination theory (CLT). The maximum allowable moment resultants of [ 12]Toffaxis laminate as well as balanced and symmetric angle-ply [ 3/ 3]s composite laminates as a function of fiber orientation angle, , are obtained using Tsai-Wu, maximum stress, maximum strain, Hashin, Tsai-Hill, Hoffman, quadric surfaces, modified quadric surfaces, and Norris failure criteria. Second, the same tests are simulated using the finite element method (FEM). Thermal residual stresses are calculated and accounted for in the failure analysis. An analysis is conducted for optimal positioning of the supports so as to ensure that intralaminar failure modes dominate interlaminar (delamination) failure mode. A test setup is then constructed accordingly and experiments are conducted. The correlation of the predicted failure loads and the experimental results is discussed. The quadric surfaces criterion is found to correlate better with the experimental results among the chosen failure criteria for the selected configurations

    Multiple intracranial arachnoid cysts.

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    A 26-year-old-man presented with intermittent headache for the last two years. The patient had no other medical history such as infection, subarachnoid hemorrhage, trauma or malignancies affecting central nervous system. A cranial CT and MR were performed. Cranial imaging revealed multiple arachnoid cysts located in right temporal fossa (Galassi type 2), left temporal fossa extending to the convexity (Galassi type 3), prepontine cistern extending to the cerebellopontine angle cistern and laterally to the left cerebellar hemisphere, cerebellar interhemispheric fissure (Fig. A). The arachnoid cyst was located left to the temporal fossa and extended to the convexity and caused a moderate shift in central cranial structures. The arachnoid cysts had the same signal intensity as cerebrospinal fluid in FLAIR and other conventional sequences (Fig. B). On diffusion MR, lesions had no restricted diffusion (Fig. C). No concomitant brain abnormality was identified. Neurological examination findings were not compatible with intracranial stasis. The patient underwent cyst fenestration operation and the diagnosis was also confirmed histopathologically. After the operation the amount of headache episodes and shift of central cranial structures decreased

    Low-Dose CT Image Enhancement Using Deep Learning

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    The application of ionizing radiation for diagnostic imaging is common around the globe. However, the process of imaging, itself, remains to be a relatively hazardous operation. Therefore, it is preferable to use as low a dose of ionizing radiation as possible, particularly in computed tomography (CT) imaging systems, where multiple x-ray operations are performed for the reconstruction of slices of body tissues. A popular method for radiation dose reduction in CT imaging is known as the quarter-dose technique, which reduces the x-ray dose but can cause a loss of image sharpness. Since CT image reconstruction from directional x-rays is a nonlinear process, it is analytically difficult to correct the effect of dose reduction on image quality. Recent and popular deep-learning approaches provide an intriguing possibility of image enhancement for low-dose artifacts. Some recent works propose combinations of multiple deep-learning and classical methods for this purpose, which over-complicate the process. However, it is observed here that the straight utilization of the well-known U-NET provides very successful results for the correction of low-dose artifacts. Blind tests with actual radiologists reveal that the U-NET enhanced quarter-dose CT images not only provide an immense visual improvement over the low-dose versions, but also become diagnostically preferable images, even when compared to their full-dose CT versions
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