• Journal of the Korean Electrochemical Society
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• v.12 no.3
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• pp.219-233
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• 2009

Mobile devices in the next generation such as camera, cell phone, network, Note PC, etc. require higher power and energy sources due to convergences of various functions. Direct methanol fuel cell (DMFC) has been focused as an attractive power source, but there are critical issues involved in its commercialization with regard to the core technologies of materials, components, and system. The requirements of key technologies are differentiated from applications and fuel supply methods. Here, the roles of the proton-conducting membrane are discussed and the current status of DMFC systems is discussed in terms of proton conductivity, methanol permeability, and water management. Materials such as perfluorinated and partially fluorinated membranes, hydrocarbon membranes, composite membranes, and other modified ionomers have been studied. These would explain the critical issues of DMFC and the role of membranes for commercialization.

• Journal of applied mathematics & informatics
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• v.30 no.1_2
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• pp.327-336
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• 2012

Let {$X_{ni}$, $i{\geq}1$, $n{\geq}1$} be an array of rowwise and pairwise negatively quadrant dependent random variables with mean zero, {$a_{ni}$, $i{\geq}1$, $n{\geq}1$} an array of weights and {$b_n$, $n{\geq}1$} an increasing sequence of positive integers. In this paper we consider some results concerning complete convergence of ${\sum}_{i=1}^{bn}a_{ni}X_{ni}$.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.18 no.1
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• pp.51-60
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• 2014

The Shortley-Weller method is a basic finite difference method for solving the Poisson equation with Dirichlet boundary condition. In this article, we review the analysis for supra-convergence of the Shortley-Weller method. Though consistency error is first order accurate at some locations, the convergence order is globally second order. We call this increase of the order of accuracy, supra-convergence. Our review is not a simple copy but serves a basic foundation to go toward yet undiscovered analysis for another supra-convergence: we present a partial result for supra-convergence for the gradient of solution.

• Advances in Computational Design
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• v.5 no.2
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• pp.177-193
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• 2020

In the present research, dynamic analysis of functionally graded (FG) graphene-reinforced beams under thermal loading has been carried out based on finite element approach. The presented formulation is based on a higher order refined beam element accounting for shear deformations. The graphene-reinforced beam is exposed to transverse periodic mechanical loading. Graphene platelets have three types of dispersion within the structure including uniform-type, linear-type and nonlinear-type. Convergences and validation studies of derived results from finite element approach are also presented. This research shows that the resonance behavior of a nanocomposite beam can be controlled by the GPL content and dispersions. Therefore, it is showed that the dynamical deflections are notably influenced by GPL weight fractions, types of GPL distributions, temperature changes, elastic foundation and harmonic load excitation frequency.

• Journal of Power System Engineering
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• v.4 no.1
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• pp.68-73
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• 2000

A mixed degree finite element solutions using hierarchical elements are investigated for convergences on a 2-D simple cases. Elements are generated block by block and each block is assigned an arbitrary solution degree. The numerical study showed that a well constructed blocks can increase the convergence and accuracy of finite element solutions. Also, it has been found that for higher order elements, the convergence trends can be deteriorated for smaller mesh sizes. A procedure for a variable fixed boundary condition has been included.

• Proceedings of the Safety Management and Science Conference
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• 2011.11a
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• pp.695-716
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• 2011

In the future, smartphone convergences are not only based on the on/offline integration, but also with the integration between mobile communications and broadcasts. Therefore, there is a need to search for new direction of mobile device that enables variety user applications that are different from the existing size and application issue. The aim of this reserch is to improve user interface of smartphone's functional attribute. The survey results in this paper showed that the most preferable attribute of smartphone among the 8 was the wireless internet 25.3%, followed by messaging 20% and application 19.8%, which totaled to 62.5%. But the samples used were mostly limited to those aged 20 through 30. So the results are not considered as a representative preference of all smartphone users, and should be considered otherwise before materializing them to a product. Therefore, for the more liable results the further research should be conducted to gather data from a variety of users of all ages, and the functional attribute should be analysed through QFD.

• Honam Mathematical Journal
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• v.39 no.1
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• pp.1-25
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• 2017

In this paper, we introduce a new scheme namely: CUIA-iterative scheme and utilize the same to prove a strong convergence theorem for quasi contractive mappings in Banach spaces. We also establish the equivalence of our new iterative scheme with various iterative schemes namely: Picard, Mann, Ishikawa, Agarwal et al., Noor, SP, CR etc for quasi contractive mappings besides carrying out a comparative study of rate of convergences of involve iterative schemes. The present new iterative scheme converges faster than above mentioned iterative schemes whose detailed comparison carried out with the help of different tables and graphs prepared with the help of MATLAB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.2C
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• pp.155-160
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• 2008

In this letter, we propose a new design of recursive systematic convolutional (RSC) codes based on the distance spectrum properties which can maximize the performance. Good constituent RSC codes of code rate 1/2 are searched by computer and presented in a table. Their performances are shown by computer simulation. New designed codes shows faster convergences according to iterative decoding and good performances.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.2
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• pp.9-17
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• 2002

For turbulent spray combustion flows a coupled numerical procedure was developed, This method was discretized by using generalized curvilinear coordinates to handle complex geometries. The preconditioning and eigenvalue rescaling techniques were employed to provide efficient convergences over a wide range of subsonic Mach numbers. The accuracy was validated by simulating the laminar cavity flow. The film cooling effect of a liquid rocket engine (KSR-III) were investigated by a spray combustion analysis. The film cooling showed a negative effect on the combustion efficiency. In the combustion chamber wall, the film cooling effect was revealed to be promoted by the production of fuel rich zone.

• Journal of Information Technology Services
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• v.8 no.3
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• pp.223-232
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• 2009

The most popular convergent services are being made mostly out of IT related services and devices. To help understand the underlying principles making convergent services the paper suggests a logical view of converging process. A service is assumed to consist of unit services that can be used in algorithmic operations to form a new convergent service. Convergence operations for a couple of unit services are typed according to whether the unit services are modified. Internal convergence leads to a new service from a combination of sub units of the two unit services. External convergences do not alter original unit services but simply combine them to form a new service. The paper also suggests several measurements to evaluate the convergent services with respect to the existing services used to create the new convergent service.