• Structural Engineering and Mechanics
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• 제11권5호
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• pp.565-574
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• 2001

Experimental investigation into the behaviour of half-scale brick masonry panels were conducted under cyclic loading normal to the bed joint and parallel to the bed joint. For each cycle, full reloading was performed with the cycle peaks coinciding approximately with the envelope curve. Unloading, however, was carried out fully to zero stress level and partially to two different stress levels of 25 percent and 50 percent of peak stress. Stability point limit exhibits a unique stress-strain curve for full unloading but it could not be established for partial unloading. Common point limit was established for all unloading-reloading patterns considered, but its location depends on the stress level at which unloading is carried to. Common point curves were found to follow an exponential formula, while residual strains versus envelope strains can be expressed by a polynomial function of a single term. The relation between residual strain and envelope strain can be used to determine the stress level at which deterioration due to cyclic loading began.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.637-640
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• 2002

The deterioration of RC deck slabs has been a serious problem and high portion of budget has been a spent for repair and strengthening of deck slab. The concrete deck slabs are subject to direct application of vehicle loading and accumulation of fatigue damage. Besides, various environmental causes. In this paper, an probabilistic study is carried out to predict exact load effects and structural capacity of deck slab during its service life, and estimate an appropriate remaining life of deck slab. To achieve this purpose the live load model is developed using by influence line including deterioration of deck slab, and deterioration model of bridge deck slab is developed. In addition, the fatigue life of reinforced concrete deck slabs considering corrosion of reinforcement are estimated based on experimental formula. This study will help rational decisions for the management and repair of reinforced concrete deck slabs.

• ETRI Journal
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• 제32권2호
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• pp.222-229
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• 2010

A conventional pseudorandom sequence generator creates only 1 bit of data per clock cycle. Therefore, it may cause a delay in data communications. In this paper, we propose an efficient implementation method for a pseudorandom sequence generator with parallel outputs. By virtue of the simple matrix multiplications, we derive a well-organized recursive formula and realize a pseudorandom sequence generator with multiple outputs. Experimental results show that, although the total area of the proposed scheme is 3% to 13% larger than that of the existing scheme, our parallel architecture improves the throughput by 2, 4, and 6 times compared with the existing scheme based on a single output. In addition, we apply our approach to a $2{\times}2$ multiple input/multiple output (MIMO) detector targeting the 3rd Generation Partnership Project Long Term Evolution (3GPP LTE) system. Therefore, the throughput of the MIMO detector is significantly enhanced by parallel processing of data communications.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.256-261
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• 2004

This paper presents a simple two-degree of freedom PID tuning table based on the CDM design method. The structure of the control system will be composed of plant, P or PI or PID controller and a pre-filter. The finalized formula can be used based on the experimental test of the plant in the same manner as the Ziegler-Nichols' second method. That is; users just need to find the critical gain and critical period experimentally and the parameters of the P, PI or PID controller with the pre-filter can be obtained by substituting the values of critical gain and critical period in the tuning table. The simulation results of the control systems utilizing the proposed controllers compared with those using the Ziegler-Nichols' second method will also be demonstrated.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.395-398
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• 2005

The acquisition of a panoramic image has been popular in recent years due to its large number of applications. In this paper, we deal with generation of a full panoramic mosaic. When it mosaicing consecutive frames, a simple alignment method may lead to local and global alignment errors. These errors can make a full-view panoramic mosaic to be cracked. In order to solve this problem, we propose the bidirectional alignment with multi-anchor (BAMA) algorithm with a basic local alignment formula. Experimental results show that we can create full panoramic mosaics stably through the proposed algorithm.

• 대한화학회지
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• 제24권1호
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• pp.20-24
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• 1980

Benzologous pyridine계 리간드의 프론티어전자밀도와 pK값을 단순 Huckel 분자궤도함수법을 이용하여 계산하였다. 이들 리간드의 양성자 첨가과정에서 이론적인 pK 값을 구하는 기본식을 유도하였으며, 이 식을 이용하여 계산한 pK값은 실험치와 잘 일치하였으며, 리간드내의 질소원자 위치에 대한 $\pi$ 전자밀도와 사이에는 병행관계가 성립됨을 보여주었다. 또한 리간드의 프론티어전자밀도의 분포로서 친전자적, 친핵적, 라디칼반응에 대하여 각각 조사하였다.

• 한국군사과학기술학회지
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• 제20권5호
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• pp.665-672
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• 2017

Supercavitation can be generated at relatively lower speeds by injecting compressed air behind the cavitator. As a result, an artificially created supercavity is deformed and its tail tends to rise due to gravitational effects. However, practical prediction of the artificial supercavity currently depends on empirical results. In this study, a mathematical model for the artificial supercavity under the gravity effect is proposed. Based on a boundary element method, geometric characteristics of the supercavity at different flow conditions are examined. The results were compared with an existing empirical formula and also experimental observations carried out at a cavitation tunnel of the Chungnam National University.

• 설비공학논문집
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• 제1권4호
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• pp.313-318
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• 1989

Experiments have been performed to find an optimum filling quantity of working fluid in a heat pipe. The optimum operation has been defined to give a minimum temperature difference between evaporator and condenser. The experimental results show that there exists an optimum filling quantity which is slightly smaller than that calculated by the well known formula from the geometry of the wick. When the concaved vapor-liquid interface at the wick is taken into account to calculate the required quantity of working fluid, the computed value agrees with the experimentally determined quantity.

• 전력전자학회논문지
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• 제21권4호
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• pp.328-334
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• 2016

This paper examines the reliability of a VSC-HVDC valve based on a modular multilevel converter (MMC) HVDC system. The main objective of this paper is to determine the redundancy of the MMC valve. Several prediction methods are introduced, but the binomial failure method is selected to be used. To determine the availability and reliability prediction of MMC valve, which comprises a DC/DC converter, a gate driver, a capacitor, and an IGBT, the failure data of the MMC module are used as the tracking data according to the experimental result. This method uses a simplified equation to find the valve redundancy by transforming the binomial function to De Moivre's formula. This method is the first to be used to find the valve margin.

• 대한기계학회논문집
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• 제19권6호
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• pp.1539-1544
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• 1995

Copper blow test to measure the forging capability of 35 ton counterblow hammer and upset of plasticine on the model hammer to investigate the change of the blow efficiency during the forging process have been performed together with finite element analyses of these experiments. The blow efficiency of the hammer has been found to be dependent on the friction and on the contact area between the die and the workpiece. The effects of the volume and the aspect ratio of the billet have not been found. Inferring from the experimental results and Schey's empirical formula on the forging load, we expect that the efficiency also varies with the flow stress of the workpiece material and with the shape complexity of the forging product.