• Journal of the Korean Mathematical Society
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• v.59 no.5
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• pp.945-962
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• 2022

For a positive integer ℓ, $\bar{A}_{\ell}(n)$ denotes the number of over-partitions of n into parts not divisible by ℓ. In this article, we find certain Ramanujan-type congruences for $\bar{A}_{r{\ell}}(n)$, when r ∈ {8, 9} and we deduce infinite families of congruences for them. Furthermore, we also obtain Ramanujan-type congruences for $\bar{A}_{13}(n)$ by using an algorithm developed by Radu and Sellers [15].

• The Journal of the Acoustical Society of Korea
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• v.14 no.5
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• pp.36-43
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• 1995

This paper presents the lousing characteristics and the time. response of ultrasonic focusing transducer which is a coupled system with an electromechanical and an acoustical component. The Finite Element Method and the Hybrid Type Infinite Element Method are applied for the analysis. The position of the focal points and the resolutions is obtained from the loosing characteristics and the time response. It is found that the transducer with the damper, which stabilizes the displacement of the radiation surface, gives a better resolution. In conclusion, the results could be applied to the design and the performance analysis of the ultrasonic focusing transducer.

• The Journal of the Acoustical Society of Korea
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• v.22 no.1
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• pp.54-60
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• 2003

The characteristics of radiation impedance for piston source on a spherical baffle are analyzed by algorithms which consists of Finite Element Method (FEM) and Hybrid type Infinite Element Method (HIEM). The results of self-radiation impedance for radiation angle and mutual radiation impedance between piston sources coincided with other reports on the spherical rigid baffle. For the spherical non-rigid baffles, the variations of self-radiation impedance and mutual-radiation impedance are identified. Therefore, these results can be applied to design and radiation characteristics analysis of acoustic transducers.

• The Journal of the Acoustical Society of Korea
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• v.13 no.2
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• pp.68-75
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• 1994

This is the second of two companion papers wich describes the wideband array transducer design procedure and the designed transducer acoustic characteristics. In addition, the result of the designed transducer acoustic characteristics by the combined Finite Element Method and Hybrid Type Infinite Element Method, is found to better than that by the equivalent circuit model method. Therefore, the technique presented in this paper could be applied in the design and the acoustic characteristics analysis of the wideband array transducer.

• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.1
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• pp.55-67
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• 2010

Decision problem called an optimal release policies, after testing a software system in development phase and transfer it to the user, is studied. The applied model of release time exploited infinite non-homogeneous Poisson process. This infinite non-homogeneous Poisson process is a model which reflects the possibility of introducing new faults when correcting or modifying the software. The failure life-cycle distribution used generalized gamma type distribution which has the efficient various property because of various shape and scale parameter. Thus, software release policies which minimize a total average software cost of development and maintenance under the constraint of satisfying a software reliability requirement becomes an optimal release policies. In a numerical example, after trend test applied and estimated the parameters using maximum likelihood estimation of inter-failure time data, estimated software optimal release time.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2516-2520
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• 2005

In this paper, finite impulse response (FIR) smoothers are proposed for discrete-time systems. The proposed FIR smoother is designed under the constraints of linearity, unbiasedness, FIR structure, and independence of the initial state information. It is also obtained by directly minimizing the performance criterion with unbiased constraints. The approach to the MVF smoother proposed in this paper is logical and systematic, while existing results have heuristic assumption, such as infinite covariance of the initial state. Additionally, the proposed MVF smoother is based on the general system model that may have the singular system matrix and has both system and measurement noises. Thorough simulation studies, it is shown that the proposed MVF smoother is more robust against modeling uncertainties numerical errors than fixed-lag Kalman smoother which is infinite impulse response (IIR) type estimator.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.111-114
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• 2001

In this paper, the electromagnetic coupling problems are tackled on slots with nonzero thickness. The analysis is carried out by combination of the thin-wire concept and the Method of Moment(MoM) for the sake of improving computation efficiency. Under the conditions to be presented, slots can be replaced with wires that have effective radii. Also, the infinite summation-type Green's functions are calculated for the parallel-pale structure. A slot in an infinite ground is analyzed and its results are compared with the measurement in a literature. Furthermore, it is examined how the slots couple in parallel plates.

• Bulletin of the Korean Mathematical Society
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• v.47 no.1
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• pp.29-37
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• 2010

We establish the existence of weak solutions in an infinite subsonic channel in the self-similar plane to the two-dimensional Burgers system. We consider a boundary value problem in a fixed domain such that a part of the domain is degenerate, and the system becomes a second order elliptic equation in the channel. The problem is motivated by the study of the weak shock reflection problem and 2-D Riemann problems. The two-dimensional Burgers system is obtained through an asymptotic reduction of the 2-D full Euler equations to study weak shock reflection by a ramp.

• 한국초전도학회:학술대회논문집
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• v.12
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• pp.25-25
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• 2002

• 한국전산유체공학회:학술대회논문집
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• 2002.05a
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• pp.53-58
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• 2002

A three-dimensional incompressible Navier-Stokes solver is developed for the flow analysis around Micro Air Vehicle(MAV) designed by MACDL(Micro Aerodynamic Control and Design Lab), Seoul National Univ., Validations of this solver are presented for two cases, first flow over the circular cylinder with infinite length, second flow over infinite wing with wing section, E387 airfoil. Simultaneously, Wind Tunnel test is performed with Flatform Wire type sir-component balance and model designed by MACDL. The numerical results are also examined through comparison with experimental data.