• 한국통신학회논문지
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• 제25권10A호
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• pp.1582-1589
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• 2000

본 논문에서는 GHz 대역에서 동작하며 소모전력이 적은 동적 D-flipflop을 제안한다. 제안하는 D-flipflop은 두 가지 측면의 장점을 제공한다. 첫째, 클럭 입력을 갖는 PMOS 트랜지스터의 개수를 줄여 기존회로와 동일한 면적하에서도 고속 동작을 할 수 있다. 둘째, 클럭 업력을 갖는 NMOS 트랜지스터 공유에 의하여 glitch를 줄이고 소모전력을 낮출 수 있다. 제안하는 D-flipflop의 성능 비교를 위하여 기존회로와 동일한 면적의 레이아웃 회로에서 소모전력 및 최대동작주파수의 측정실험을 한다. 제안하는 회로의 응용 예로 고속 prescaler에서 동일한 방법의 특성실험을 한다. 성능분석결과 기존 회로에 비하여 동작속도와 전력소모 측면에서 우수한 성능을 나타냄을 확인하였다.

• Journal of Information Processing Systems
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• 제18권4호
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• pp.457-469
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• 2022

Hydraulic concrete buildings in the northwest of China are often subject to the combined effects of low-temperature frost damage, during drying and wetting cycles, and salt erosion, so the study of concrete deterioration prediction is of major importance. The prediction model of the relative dynamic elastic modulus (RDEM) of four different kinds of modified concrete under the special environment in the northwest of China was established using Grey residual Markov theory. Based on the available test data, modified values of the dynamic elastic modulus were obtained based on the Grey GM(1,1) model and the residual GM(1,1) model, combined with the Markov sign correction, and the dynamic elastic modulus of concrete was predicted. The computational analysis showed that the maximum relative error of the corrected dynamic elastic modulus was significantly reduced, from 1.599% to 0.270% for the BS2 group. The analysis error showed that the model was more adjusted to the concrete mixed with fly ash and mineral powder, and its calculation error was significantly lower than that of the rest of the groups. The analysis of the data for each group proved that the model could predict the loss of dynamic elastic modulus of the deterioration of the concrete effectively, as well as the number of cycles when the concrete reached the damaged state.

• Current Optics and Photonics
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• 제7권4호
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• pp.337-344
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• 2023

Three-point bending is the main method for measuring the elastic modulus of a thin plate. Although various displacement transducers may be used to measure the bending, these are single-point measurements, and it is difficult to eliminate the error caused by eccentric load and shear force. Error-correction models for the elastic modulus of quartz glass using digital speckle interferometry are proposed for eccentric load and shear force. First, the positional misalignment between maximum deflection and load is analyzed, and the error caused by eccentric load is corrected. Then, the additional displacement caused by shear force at different positions of the quartz glass plate is explored. The effect of shear deformation is also corrected, by measuring two points. Since digital speckle interferometry has the advantage of full-field measurement, it can simultaneously obtain deflection data for multiple points to realize error correction. Experimental results are presented to demonstrate that the proposed model can effectively correct the measurement error of the elastic modulus.

• 한국도로학회논문집
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• 제16권3호
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• pp.35-41
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• 2014

PURPOSES : The dynamic modulus for a specimen can be determined by using either the non-destructed or destructed testing method. The Impact Resonance Testing (IRT) is the one of the non-destructed testing methods. The MTS has proved the source credibility and has the disadvantages which indicate the expensive equipment to operate and need a lot of manpower to manufacture the specimens because of the low repeatability with an experiment. To overcome these shortcomings from MTS, the objective of this paper is to compare the dynamic modulus obtained from IRT with MTS result and prove the source credibility. METHODS : The dynamic modulus obtained from IRT could be determined by using the Resonance Frequency (RF) from the Frequency Response Function (FRF) that derived from the Fourier Transform based on the Frequency Analysis of the Digital Signal Processing (DSP)(S. O. Oyadigi; 1985). The RF values are verified from the Coherence Function (CF). To estimate the error, the Root Mean Squared Error (RMSE) method could be used. RESULTS : The dynamic modulus data obtained from IRT have the maximum error of 8%, and RMSE of 2,000MPa compared to the dynamic modulus measured by the Dynamic Modulus Testing (DMT) of MTS testing machine. CONCLUSIONS : The IRT testing method needs the prediction model of the dynamic modulus for a Linear Visco-Elastic (LVE) specimen to improve the suitability.

• International Journal of Control, Automation, and Systems
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• 제5권1호
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• pp.1-7
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• 2007

In this paper, the necessary and sufficient conditions for strict positive realness of the rational transfer functions directly from basic definitions in the frequency domain are studied. A new frequency domain approach is used to check if a rational transfer function is a strictly positive real or not. This approach is based on the Taylor expansion and the Maximum Modulus Principle which are the fundamental tools in the complex functions analysis. Four related common statements in the strict positive realness literature which is appeared in the control theory are discussed. The drawback of these common statements is analyzed through some counter examples. Moreover a new necessary condition for strict positive realness is obtained from high frequency behavior of the Nyquist diagram of the transfer function. Finally a more simplified and completed conditions for strict positive realness of single-input single-output linear time-invariant systems are presented based on the complex functions analysis approach.

• The Korean Journal of Ceramics
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• 제6권1호
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• pp.37-42
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• 2000

To reduce shrinkage and the possibility of fracture during ambient pressure drying, it is of great importance to increase the strength and stiffness of the wet gels. In this paper is presented the strengthening and stiffening of wet silica gels prepared from sodium silicate (water glass) as well as properties of the corresponding xerogels. By washing gels containing different initial silica contents in water solutions at elevated pH, a maximum in shear modulus of ~4 MPa was obtained. The maximum stiffness enabled xerogels with bulk density of 0.28g/$\textrm{cm}^3$ to be made regardless of silica content and washing conditions. However, by aging the wet gels in a solution providing fresh monomers to the gel network, a shear modulus of 20 MPa was obtained after 27h. By this method monolithic xerogels with a density down to ~0.2g/$\textrm{cm}^3$ was prepared. The results are compared to alkoxide based gels.

• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.251-256
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• 2015

In this paper, an systematic approach is presented, in which the bridge-type traffic sign structure is body out by CSDDA PrePost Processor. There is dead load and wind load that is working on the structure which will make force and moment. Analyzied the stress distribution of the standard form and by changing the shape, compared the safety in terms of deflection and stress (with the standard form) to know the effect of each component in the bridge-type traffic sign structure. The safety of deflection and stress is evaluated by maximum distance/100) and ASIC code respectively. The standard form of bridge-type traffic sign structure is established by two pairs of pillar and two pairs of floor beam. Replaced the links which is consist of flange and screws as the torsion spring and nm our analysis program. By adjusting variable of rigidity modulus of torsion spring, moment between column and beam is controled depending on value of rigidity modulus.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.831-835
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• 2008

Recently, the use of C.S.G is gradually increasing as the construction material for dam, road, revetment and so on. The strength characteristics of C.S.G is affected by various influence factors such as specimen size, maximum grain size and water contents. Therefore, When designing and constructing the C.S.G structure, it is very important for us to understand the nature of used materials well and to test it's quality. Commonly, C.S.G strength test is used the cylinders specimen size of $15{\times}30$ at KS F2405. But, the specimen size extracted from the field structure is not regular. This paper aims at offering the experimental data about the compressive strength and elasticity modulus by change of the specimen size for the effective quality control of the C.S.G structure.

• Journal of the Korean Wood Science and Technology
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• 제41권5호
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• pp.392-398
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• 2013

This study investigated the effect of test zone selection for evaluating bending strength of visually graded lumber. This will contribute to the understanding of two different methods under different standards. In method I, the major defect was randomly placed in the test specimen. In method II, the major defect was randomly placed in the maximum moment zone (MMZ). The results showed that the method II is more accurate for reflecting the effect of defects governing the grade of lumber. Unless the maximum strength-reducing defect (MSRD) is placed in MMZ, the evaluated value would be higher than that of MSRD. For evaluating the modulus of rupture (MOR) of visually graded lumber in test set-up of Method I, the Eq. (5) needs to be considered.

• 한국지반환경공학회 논문집
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• 제12권5호
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• pp.59-63
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• 2011

전단탄성계수와 감쇠비와 같은 동적지반계수는 반복하중과 동적하중을 받는 지반구조물 설계에서 중요한 요소이다. 선형 한계변형률 내에서 미소변형률에 관한 전단탄성계수와 감쇠비는 변형률과 관계없이 일정하다. 전단탄성계수는 최대전단탄성계수로 감쇠비는 최소 감쇠비로 고려하였다. 동적변형특성 범주내의 최대선형탄성계수에 관련된 많은 시험들이 수행됨과 동시에 간극비, 과압밀비, 구속압, 지질이력, PI 그리고 하중주기수에 관련된 많은 인자들이 동적지반특성에 영향을 미친다. 그러나 그라우팅에 의해 향상된 지반동적특성에 관한 연구는 지하연속벽시공, 심층혼합처리공법, 강관다단그라우팅과 같이 미비한 실정이다. 본 논문에서는 그라우팅에 의해 향상된 동적지반특성을 연구하기 위하여 함수비(20%, 25%, 30%), 그라우트 주입율(5%, 10%, 15%),양생기간(7일, 28일)을 변화시키면서 공진주시험을 실시하였다. 그 결과, 밀크 그라우트의 주입율과 재령, 함수비에 따라 동적계수인 전단탄성계수와 감쇠비가 영향을 받는 것으로 나타났다.