• 한국전자파학회논문지
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• 제24권11호
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• pp.1047-1054
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• 2013

본 논문은 다중 대역 레이더 수신기의 소형화를 위한 이중 모드 주파수 혼합기를 구현하였다. 제안한 혼합기는 역병렬 다이오드(anti-parallel diode)를 이용하였고, 제어 전압 유무에 따라 기본파 혼합기 또는 부고조파 혼합기로 동작한다. 제어 전압을 인가하여 기본파 혼합기로 동작하는 경우, X-대역에서 -10 dB 변환 손실, 2.0 dBm P1dB 특성을 나타내었고, 제어 전압을 인가하지 않은 부고조파 혼합기로 동작하는 경우 K-대역에서 -10 dB 변환 손실, 2.0 dBm P1dB 특성을 나타내었다.

• Journal of Biosystems Engineering
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• 제15권2호
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• pp.99-109
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• 1990

Rough rice is subjected to a series of static and dynamic forces during mechanical harvesting, handling and processing operations. The mechanical properties such as bioyield point, compressive strength, and deformations at the bioyield point and rupture point are important engineering data needed to develop processing machines and to determine reasonable operating conditions for these machines. The objectives of this study were to determine the mechanical properties of the rough rice kernel at loading rate of 0.664 mm/min and 1.673 mm/min and at various moisture contents, and to examine the effect of the moisture content and the loading rate on these mechanical properties. The follwing results were obtained from the study. 1. Bioyield point, rupture point, bioyield strength and ultimate strength of the rough rice kernel generally decreased in magnitude with an increase in moisture content. A little larger values of these mechanical properties were obtained at the higher loading rate. The rough rice variety and the loading rate affected significantly these mechanical properties at low moisture content, but not at the higher moisture levels. 2. Bioyield point of the sample grains varied from 20 to 80 N, and rupture point varied from 45 to 130N. Bioyield point for Japonica-type rough rice was a little higher than that for Indica-type rough rice, but there were little differnces in rupture point between two types of rough rice. 3. Bioyield strength and ultimate strength of the Japonica-type rough rice varied from 10 MPa. to 39 MPa., and from 13 MPa. to 45 MPa. respectively. Those of the Indica-type rough rice varied from 12 MPa. to 42 MPa., and from 15 MPa. to 53 MPa. respectively. 4. Deformations at bioyield point and rupture point ranged from 0.18 mm/min to 0.26 mm, and from 0.28 mm to 0.53 mm respectively. These deformations decreased with an increase in moisture content up to moisture content of approximately 17% (w.b.) and increased again thereafter. 5. Regression equations were developed to predict these mechanical properties for the rough rice kernel as a function of moisture content.

• Journal of applied mathematics & informatics
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• 제25권1_2호
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• pp.329-337
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• 2007

In the paper, we obtain the existence of positive solutions and establish a corresponding iterative scheme for BVPs $$\{^{\;(\phi_p(u'))'\;+\;q(t)f(t,u)=0,\;0\;<\;t\;<\;1,}_{\;u(0)\;-\;B(u'({\eta}))\;=\;0,\;u'(1)\;=\;0}$$ and $$\{^{\;(\phi_p(u'))'\;+\;q(t)f(t,u)=0,\;0\;<\;t\;<\;1,}_{\;u'(0)\;=\;0,\;u(1)+B(u'(\eta))\;=\;0.}$$. The main tool is the monotone iterative technique. Here, the coefficient q(t) may be singular at t = 0, 1.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(5)
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• pp.207-209
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• 2000

In this paper, we developed a feature point detection algorithm that detects upstroke point(S), peak point(P), incisura(C) point from radial pulse waveform which obtained by using the developed radial pulse transducer. As the results of experiment the three kinds of parameters can extracted with effectively from normal radial pulse waveform.

• 한국정밀공학회지
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• 제18권9호
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• pp.61-70
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• 2001

This paper introduces a new digitization method with sensor fusion for shape measurement in reverse engineering. Digitization can be classified into contact and non-contact type according to the measurement devices. Important thing in digitization is speed and accuracy. The former is excellent in speed and the latter is good for accuracy. Sensor fusion in digitization intends to incorporate the merits of both types so that the system can be automatized. Firstly, non-contact sensor with vision system acquires coarse 3D point data rapidly. This process is needed to identify and loco]ice the object located at unknown position on the table. Secondly, accurate 3D point data can be automatically obtained using scanning probe based on the previously measured coarse 3D point data. In the research, a great number of measuring points of equi-distance were instructed along the line acquired by the vision system. Finally, the digitized 3D point data are approximated to the rational B-spline surface equation, and the free-formed surface information can be transferred to a commercial CAD/CAM system via IGES translation in order to machine the modeled geometric shape.

• Journal of electromagnetic engineering and science
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• 제5권3호
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• pp.112-116
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• 2005

This paper presents a broadband two-stage low noise amplifier(LNA) operating from 3 to 10 GHz, designed with 0.18 ${\mu}m$ RF CMOS technology, The cascode feedback topology and broadband matching technique are used to achieve broadband performance and input/output matching characteristics. The proposed UWB LNA results in the low noise figure(NF) of 3.4 dB, input/output return loss($S_{11}/S_{22}$) of lower than -10 dB, and power gain of 14.5 dB with gain flatness of $\pm$1 -dB within the required bandwidth. The input-referred third-order intercept point($IIP_3$) and the input-referred 1-dB compression point($P_{ldB}$) are -7 dBm and -17 dBm, respectively.

• Nonlinear Functional Analysis and Applications
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• 제26권2호
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• pp.289-301
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• 2021

In this research, we interpret the notion of a b-cyclic (𝚽, C, D)-contraction for the pair (g, S) of self-mappings on the set Y. We employ our definition to introduce some common fixed point theorems for the two mappings g and S under a set of conditions. Also we introduce an example to support our results.

• 호남수학학술지
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• 제45권1호
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• pp.1-24
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• 2023

In the present paper, we prove common fixed point theorems for a pair of weakly compatible mappings under implicit contractive relation in quasi-partial S_b-metric spaces. We also provide an illustrative example to support our results. Furthermore, we will use the results obtained for application to two boundary value problems for the second-order differential equation. Also, we prove a common solution for the nonlinear fractional differential equation.

• 한국정보처리학회논문지
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• 제4권10호
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• pp.2512-2520
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• 1997

B-ISDN 사용자 망 접면에서 호/연결 제어를 위한 신호 기능은 ITU-T의 Q.2931과 ATM Forum의 UNI 3.1이 대표적이다. 점대점 호/연결 제어 절차를 제공하는 Q.2931은 공중망을 구성하는 장치에 적용이 되며, ATM Forum의 UNI 3.1은 여러 가지의 단말 장치 위주의 ATM 사설망을 구성하는데 적용된다. 국내의 B-ISDN 개발 사업에서는 방 장치인 ATM소형 교환기, B-NT 등과 단말장치인 B-TA등을 개발하였다. 그러나 B-ISDN에서 다양한 서비스를 제공하기 위해서는 여러 종류의 단말장치들을 필요로 한다. 공중망에서 UNI 3.1 단말 장치를 수용할 수 있다면, 여러 종류의 단말장치들을 확보할 수 있으므로 매우 효율적이다. 그러므로, 본 논문에서는 B-ISDN 공중망에 UNI 3.1 단말 장치를 접속하여 점대점 신호 절차 수행 시에 발생할 수 있는 문제점들을 예측하고, 호/연결이 원만하게 진행될 수 있는 방안들을 제안한다.

• Journal of Computational Design and Engineering
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• 제2권4호
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• pp.218-232
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• 2015

Piecewise linear (G01-based) tool paths generated by CAM systems lack $G_1$ and $G_2$ continuity. The discontinuity causes vibration and unnecessary hesitation during machining. To ensure efficient high-speed machining, a method to improve the continuity of the tool paths is required, such as B-spline fitting that approximates G01 paths with B-spline curves. Conventional B-spline fitting approaches cannot be directly used for tool path B-spline fitting, because they have shortages such as numerical instability, lack of chord error constraint, and lack of assurance of a usable result. Progressive and Iterative Approximation for Least Squares (LSPIA) is an efficient method for data fitting that solves the numerical instability problem. However, it does not consider chord errors and needs more work to ensure ironclad results for commercial applications. In this paper, we use LSPIA method incorporating Energy term (ELSPIA) to avoid the numerical instability, and lower chord errors by using stretching energy term. We implement several algorithm improvements, including (1) an improved technique for initial control point determination over Dominant Point Method, (2) an algorithm that updates foot point parameters as needed, (3) analysis of the degrees of freedom of control points to insert new control points only when needed, (4) chord error refinement using a similar ELSPIA method with the above enhancements. The proposed approach can generate a shape-preserving B-spline curve. Experiments with data analysis and machining tests are presented for verification of quality and efficiency. Comparisons with other known solutions are included to evaluate the worthiness of the proposed solution.