• Communications of the Korean Mathematical Society
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• v.38 no.2
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• pp.355-364
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• 2023

In this paper, we investigate the sums of the elements in the finite set $\{x^k:1{\leq}x{\leq}{\frac{n}{m}},\;gcd_u(x,n)=1\}$, where k, m and n are positive integers and gcd_u(x, n) is the unitary greatest common divisor of x and n. Moreover, for some cases of k and m, we can give the explicit formulae for the sums involving some well-known arithmetic functions.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.211-218
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• 2017

In this study, we implemented IoT Sensor Network using Mobius Platform and implemented four kinds of Z-wave sensors applicable to smart home service to verify its performance. The 12 common service functions (CSF) provided by Mobius enable application services including status monitoring of sensors to be implemented quickly. The standard service procedures and protocols have eliminated the design process of the system and shortened the meeting time for establishing protocol between application software developer, gateway developer and sensor developer, and discussion time for adjustment of opinion. We confirmed that the application service based on the implemented sensor network and the implementation of IoT sensor can shorten the development schedule, and confirmed that most of the products purchased in the market can be accommodated without change. We hope that such speediness and openness will be able to meet the demands of various services and contribute to expanding services and creating new markets.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.59-64
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• 2006

A new method to obtain explicit re-parameterization that preserves the curve degree and parametric domain is presented in this paper. The re-parameterization brings a curve very close to the arc length parameterization under $L_2$ norm but with less segmentation. The re-parameterization functions we used are $C^1$ continuous piecewise rational linear functions, which provide more flexibility and can be easily identified by solving a quadratic equation. Based on the outstanding performance of Mobius transformation on modifying pieces with monotonic parametric speed, we first create a partition of the original curve, in which the parametric speed of each segment is of monotonic variation. The values of new parameters corresponding to the subdivision points are specified a priori as the ratio of its cumulative arc length and its total arc length. $C^1$ continuity conditions are imposed to each segment, thus, with respect to the new parameters, the objective function is linear and admits a closed-form optimization. Illustrative examples are also given to assess the performance of our new method.

• Communications of the Korean Mathematical Society
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• v.17 no.1
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• pp.165-173
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• 2002

We first review Ramaswami's find Apostol's identities involving the Zeta function in a rather detailed manner. We then present corrected, or generalized formulas, or a different method of proof for some of them. We also give closed-form evaluation of some series involving the Riemann Zeta function by an integral representation of ζ(s) and Apostol's identities given here.