• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.778-783
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• 2003

The problem considered in this paper is about the collocation of sensor and actuator for the active control of sound and vibration. It is well-known that a point collocated sensor-actuator pair offers an unconditional stability with very high performance when it is used with a direct velocity feedback (DVFB) control, because the pair has strictly positive real (SPR) property. In order to utilize this SPR characteristics, a matched piezoelectric sensor and actuator pair is considered, but this pair suffers from the in-plane motion coupling problem with the out-of$.$plane motion due to the piezo sensor and actuator interaction. This coupling phnomenon limits the stability and performance of the matched pair with DVFB control. As a new alternative, a point sensor and piezoelectric actuator pair is also considered, which provides SPR property in all frequency range except at the first resonance in very low frequency. This non-SPR resonance could be minimized by applying a phase lag compensator.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.7
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• pp.619-625
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• 2004

Direct velocity feedback (DVFB) control is known that it offers an unconditional stability with very high performance when the control strategy is applied at a point collocated sensor and actuator pair. because the sensor-actuator pair has strictly positive real (SPR) property In this paper, two types of collocated sensor-actuator pairs are considered for practical active vibration control of a structure. They are a Point collocated sensor-actuator pair and a point sensor-distributed actuator pair. Both pairs with DVFB show robust stability and performance. It is noted that the collocated point sensor-actuator ultimately acts as a “skyhook” damper, hut the point sensor-distributed actuator pair with DVFB acts as a “skyhook” rotational damper pair.

• Bulletin of the Korean Mathematical Society
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• v.56 no.3
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• pp.563-568
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• 2019

This study is concerned with the approximation properties of pairs. For ${\lambda}{\geq}1$, we prove that given a Banach space X and a closed subspace $Z_0$, if the pair ($X,Z_0$) has the ${\lambda}$-bounded approximation property (${\lambda}$-BAP), then for every ideal Z containing $Z_0$, the pair ($Z,Z_0$) has the ${\lambda}$-BAP; further, if Z is a closed subspace of X and the pair (X, Z) has the ${\lambda}$-BAP, then for every separable subspace $Y_0$ of X, there exists a separable closed subspace Y containing $Y_0$ such that the pair ($Y,Y{\cap}Z$) has the ${\lambda}$-BAP. We also prove that if Z is a separable closed subspace of X, then the pair (X, Z) has the ${\lambda}$-BAP if and only if for every separable subspace $Y_0$ of X, there exists a separable closed subspace Y containing $Y_0{\cup}Z$ such that the pair (Y, Z) has the ${\lambda}$-BAP.

• New Physics: Sae Mulli
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• v.68 no.11
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• pp.1225-1230
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• 2018

Schwinger pair production of electrons and positrons in a strong electric field is a prediction of nonperturbative quantum field theory, in which the out-vacuum is superposed of multi-particle states of the in-vacuum. Solving the Dirac or Klein-Gordon equation in the background field, though a linear wave equation, and finding the pair-production rate is a difficult or nontrivial job. The phase-integral method has recently been introduced to compute the pair production in space-dependent electric fields, and a complex analysis method has been employed to calculate the pair production in time-dependent electric fields. In this paper, we apply the complex analysis method to a Sauter-type electric field and other hyperbolic-type electric fields that vanish in the past and future and show that the Stokes phenomena in pair production occur when the time-dependent frequency for a given momentum has finite simple poles (polons) with pure imaginary residues.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.792-795
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• 2005

The guide-ways of precision machine tools are one of important element of machine tools. It has usually a pair of surfaces for constraint of one direction with bearing. In the case of precision machine tools, non-contact bearing such as hydrostatic bearing and aerostatic bearing is adopted usually. In this case, profiles of rails has effect on straightness and the clearance of bearing has effect on stiffness of guide way, which changes to higher if clearance changes to smaller. The clearance is varied along moving table according to relative distance of pair of rails. The relative distance of pair of rail can be divided by three properties. First and second properties are straightness of each pair of rail and bearing pad. And, third is parallelism about pair of rails and pairs of bearing pad. There are several methods for measuring straightness of each surface such as reversal method, sequential two point method, and way straightness. These straightness measuring methods are always acquiring deviation of profile from eliminating linear fitted inclined line and don't have the information of parallelism. Therefore, to get the small clearance for high stiffness, the straightness of rail and bearing pad and parallelism about pair of rails and pair of bearing pads are measured for correction such as regrinding, reassembling and lapping. In this research, new and easy method for measuring parallelism of pair of rails is suggested. Two displacement probe and sensor stage, which is carry on the displacement sensor, are needed. The simulation and experiment was accomplished about pair of horizontal guide way to confirm the measurement of parallelism. And, the third probe is added to measure the straightness of each rails by sequential two point method. From the estimation of combined these two methods, it is confirmed that the profiles of a pairs of rails can be measured.

• Journal of Digital Contents Society
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• v.19 no.9
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• pp.1663-1669
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• 2018

Pair programming is a software development technique in which two programmers work together at one computer. One writes code while the other reviews the code, and they switch roles frequently. Pair-programming practice in school programming lab is expected to improve the learning performance, provide collaboration experience, and promote interactions between students. This work finds out how students accept pair-programming, what make students reluctant to join pair-programming by repeated questionnaire surveys in a college programming lab class. Based on these findings aome guidelines for school pair-programming are provided. First, students should be allowed to choose to do pair-programming or not. Second, various obstacles that make students hesitate to switch roles should be removed. Third, the pair matching should be made with great care.

• Journal of applied mathematics & informatics
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• v.42 no.2
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• pp.367-377
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• 2024

Let G = (V, E) be a graph with p-vertices and q-edges and let R^◦ be a finite zero ring of order n. An injective function f : V (G) → {r₁, r₂, _…, r_k}, where r_i ∈ R^◦ is called vertex pair sum k-zero ring labeling, if it is possible to label the vertices x ∈ V with distinct labels from R^◦ such that each edge e = uv is labeled with f(e = uv) = [f(u) + f(v)] (mod n) and the edge labels are distinct. A graph admits such labeling is called vertex pair sum k-zero ring graph. The minimum value of positive integer k for a graph G which admits a vertex pair sum k-zero ring labeling is called the vertex pair sum k-zero ring index denoted by 𝜓_pz(G). In this paper, we defined the vertex pair sum k-zero ring labeling and applied to some graphs.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.4
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• pp.340-349
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• 1995

There are several problems in a fishing by the midwater pair trawl net which is used in Denmark; steeply decreasing of the net height with the towing speed increasing, the larger volume of the fishing gear in comparison with the size of the trawler, and catching of a float in a mesh, etc. To prevent steeply decreasing of the net height with the towing speed increasing and catching of a float in a mesh, it is sometimes more useful to use the kite instead of floats. This paper describes the hydrodynamic drag and the opening efficiency of the midwater pair trawl net and the midwater kite pair trawl net obtained by the model test in the circulation water channel. The results can be summarized as follows; 1. The hydrodynamic drag of the midwater kite pair trawl net is about 0.7 times smaller than that of the midwater pair trawl net. 2. The net height, mouth area and filtering volume of the midwater kite pair trawl net are smaller then those of the midwater pair trawl net when the towing speed is below 2.5knots, almost the same at 2.7knots, and are larger over 3.0knots. The net width of the midwater kite pair trawl net is same as that of the midwater pair trawl net. 3. The shapes of net mouth of both net are an oval steeply flatted with the towing speed increasing. The filtering volume of the midwater kite pair trawl net is larger then that of the midwater pair trawl net by 3% at 3.0knots, 11% at 4.0knots, and 16% at 5.0knots respectively.

• Journal of Digital Convergence
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• v.16 no.1
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• pp.117-124
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• 2018

The purpose of this study was to evaluate the effects of PAIR leadership program which can make one's own for solving problems of conflicts through understanding of self and the environmental. For this, the PAIR leadership were administered in 10 sessions for 60 minutes with 16 of the adjustment soldiers and 20 of the maladjustment soldiers of the military alternative social workers. The pre-post on the behavioral change will, interpersonal efficacy and the self-regulation level were assessed. The results were as the PAIR he maladjustment soldiers group reported significantly higher score on level of the behavioral change will, interpersonal efficacy and the self-regulation. Also the adjustment soldiers reported significantly on interpersonal efficacy and the self-regulation. This results suggest that the PAIR readership program can be applied effectively for promotion of the behavioral change will, the self-regulation.

• Journal of the Korean Mathematical Society
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• v.42 no.3
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• pp.555-571
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• 2005

A pair of pants $\Sigma(0,3)$ is a building block of oriented surfaces. The purpose of this paper is to formulate the matrix presentations of elements of the Teichmuller space of a pair of pants. In the level of the matrix group $SL(2,\mathbb{R})$, we shall show that an odd number of traces of matrix presentations of the generators of the fundamental group of $\Sigma(0,3)$ should be negative.