this paper presents a new design for a microstrip dual-band band-pass microstrip filter (bpf) with suitable isolation between two passbands. in this design, a basic structure is used to achieve a desirable frequency characteristic in the passband. in this regard, defected ground structure (dgs) is implemented to reach optimum parameters of the filter such as bandwidth, return loss, insertion lo...

The advent of e-commerce has prompted many manufacturers to redesign their traditionalchannel structure by engaging in direct sales. In this paper, we present a dual channel inventory modelbased on queuing theory in a manufacturer-retailer supply chain, consisting of a traditional retailchannel and a direct channel which stocks are kept in both upper and lower echelon. The systemreceives stocha...

a heyting algebra is a distributive lattice with implication and a dual $bck$-algebra is an algebraic system having as models logical systems equipped with implication. the aim of this paper is to investigate the relation of heyting algebras between dual $bck$-algebras. we define notions of $i$-invariant and $m$-invariant on dual $bck$-semilattices and prove that a heyting semilattice is equiva...

different regions of a country generally have different levels of agricultural development. in fact, there is a kind of heterogeneity that makes the investigation of the agricultural development trends in provinces of the country undeniable. the present article aims to analyze the level of agricultural development and its imbalance in rural regions of west azerbaijan for urban levels in 2000s. ...

factor  is introduced for direct head loss calculation and sizing in dual-diameter laterals of sprinkler and trickle irrigation systems when the hazen-williams equation is to be applied. application of this factor prevents trial and error and uses fewer head-loss equations in calculating the total friction loss and designing dual-diameter laterals. the proposed factor is a function of total num...

in this paper, we first discuss about canonical dual of g-frameλp = {λip ∈ b(h, hi) : i ∈ i}, where λ = {λi ∈ b(h, hi) :i ∈ i} is a g-frame for a hilbert space h and p is the orthogonalprojection from h onto a closed subspace m. next, we provethat, if λ = {λi ∈ b(h, hi) : i ∈ i} and θ = {θi ∈ b(k, hi) :i ∈ i} be respective g-frames for non zero hilbert spaces hand k, and λ and θ are unitarily e...

‎In this article‎, ‎we formulate two dual models Wolfe and Mond-Weir related to symmetric nondifferentiable multiobjective programming problems‎. ‎Furthermore‎, ‎weak‎, ‎strong and converse duality results are established under $K$-$G_f$-invexity assumptions‎. ‎Nontrivial examples have also been depicted to illustrate the theorems obtained in the paper‎. ‎Results established in this paper unify...

the theory of c-frames and c-bessel mappings are the generalizationsof the theory of frames and bessel sequences. in this paper, weobtain several equivalent conditions for dual of c-bessel mappings.we show that for a c-bessel mapping $f$, a retrievalformula with respect to a c-bessel mapping $g$ is satisfied if andonly if $g$ is sum of the canonical dual of $f$ with a c-besselmapping which  wea...

this paper presents an e-ring shaped printed monopole antenna for uwb applications with dual notched bands performance. in order to generate single frequency band notch function, we applied a u-ring shaped monopole antenna, and by inserting a rectangular ring in the centre of it an e-ring shaped radiating patch created and a dual band-notch function can be achieved. the measured bandwidth of th...