نتایج جستجو برای: frequency response constraints

تعداد نتایج: 1578354  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی خواجه نصیرالدین طوسی - دانشکده مهندسی برق و کامپیوتر 1391

power transformers are important equipments in power systems. thus there is a large number of researches devoted of power transformers. however, there is still a demand for future investigations, especially in the field of diagnosis of transformer failures. in order to fulfill the demand, the first part reports a study case in which four main types of failures on the active part are investigate...

Journal: :iranian journal of radiation research 0
a. mirzajani medical physics group, tehran university of medical sciences, tehran, iran n. riyahi-alam medical physics group, tehran university of medical sciences, tehran, iran m.a. oghabian medical physics group, tehran university of medical sciences, tehran, iran k. firuznia radiology group, tehran university of medical sciences, tehran, iran h. saberi neurosurgery group, tehran university of medical sciences, tehran

abstract  background: the brain response to temporal frequencies (tf) has been already reported, but with no study reported for different tf with respect to various spatial frequencies (sf).  materials and methods: fmri was performed by 1.5t ge-system in 14 volunteers during checkerboard, with tfs of 4, 6, 8 and 10hz in low and high sfs of 0.5 and 8cpd.  results: average percentage bold signal ...

An efficient technique is presented for optimum design of structures with both natural frequency and complex frequency response constraints. The main ideals to reduce the number of dynamic analysis by introducing high quality approximation. Eigenvalues are approximated using the Rayleigh quotient. Eigenvectors are also approximated for the evaluation of eigenvalues and frequency responses. A tw...

2005
Liuping Wang Peter J. Gawthrop Peter C. Young

Although structural constraints such as model order and time delay have been incorporated in the continuous time system identification since its origin, the constraints on the estimated model parameters were rarely enforced. This paper proposes a continuous time system identification approach with constraints. It shows that by incorporating physical parameter information known a priori as hard ...

Journal: :iranian journal of electrical and electronic engineering 0
منیری moniri فرشاد farshad

power transformers are key components in electrical power supplies and their failure could cause severe consequences on continuity of service and also generates substantial costs. identifying problems at an early stage, before catastrophic failure occurs, is a great benefit for reliable operation of power transformers. frequency response analysis (fra) is a new, well-known and powerful diagnost...

This paper presents a fixed-end two-mass system (TMS) with end constraints that permits uncoupled solutions for different masses. The coupled nonlinear models for the present fixed-end TMS were solved using the continuous piecewise linearization method (CPLM) and detailed investigation on the effect of mass-ratio on the TMS response was conducted. The investigations showed that increased mass-r...

Filters are particularly important class of LTI systems. Digital filters have great impact on modern signal processing due to their programmability, reusability, and capacity to reduce noise to a satisfactory level. From the past few decades, IIR digital filter design is an important research field. Design of an IIR digital filter with desired specifications leads to a no convex optimization pr...

A generalized simplified model for describing the dynamic behavior of distributed parameter systems is proposed. The various specific characteristics of gain and phase angle of distributed parameter systems are investigated from frequency response formulation and complex plane representation of the proposed simplified model. The complex plane investigation renders some important inequality cons...

Journal: :ماشین های کشاورزی 0
رمضان میرزایی سعید مینایی محمدهادی خوش تقاضا علی محمد برقعی

the most important quality indicator of fruits is the flesh firmness which is well correlated to their young’s modulus. in this research variation of vibration characteristics (shape modes, natural frequency) of apple due to change of material characteristics (density, young's models, poisson ratio) and apple volume was investigated using finite element simulation. an image processing technique...

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