• Steel and Composite Structures
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• 제11권1호
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• pp.39-58
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• 2011

The subject of the ongoing research work is to analyze the composite action of the structural elements of composite slabs with profiled steel decking by experimental and numerical studies. The mechanical and frictional interlocks result in a complex behaviour and failure under horizontal shear action. This is why the design characteristics can be determined only by standardized experiments. The aim of the current research is to develop a computational method which can predict the behaviour of embossed mechanical bond under shear actions, in order to derive the design characteristics of composite slabs with profiled steel decking. In the first phase of the research a novel experimental analysis is completed on an individual concrete encased embossment of steel strip under shear action. The experimental behaviour modes and failure mechanisms are determined. In parallel with the tests a finite element model is developed to follow the ultimate behaviour of this type of embossment, assuming that the phenomenon is governed by the failure of the steel part. The model is verified and applied to analyse the effect of embossment's parameters on the behaviour. In the extended investigation different friction coefficients, plate thicknesses, heights and the size effects are studied. On the basis of the results the tendencies of the ultimate behaviour and resistance by the studied embossment's characteristics are concluded.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 춘계 학술논문 발표대회 학계
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• pp.219-223
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• 2009

This paper is the result of investigation of ONO PPSM(ONO PORTABLE SLIP METER) by way of experiment to see the validity as a slip meter, ONO PPSM is a portable slip meter which was made up for the weak points of O-Y PSM(ONO-YOSHIOKA PULL SLIP METER) which takes an accurate measurement of the slip resistance but very heavy and hard to operate. In order to know the stability of the measurement result of ONO PPSM, we measured the slip resistance against 4 different kind of floor materials. As a result of this, we found out that the coefficient of variability of CSR' is less than 0.05. Also, we verified the relation between CSR' and CSR. more specifically by doing the slip test against 7 different kinds of inorganic matter floor materials. We increased the usability of ONO PPSM as a slip meter by suggesting the method of sharing the evaluation index of slip of CSR' and C.S.R.

• Journal of Power Electronics
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• 제11권5호
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• pp.621-631
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• 2011

In space qualified DC-DC converters, optimization of the following electrical characteristics is of greater interest in comparison with other specifications; power loss/efficiency, output voltage ripple and volume/weight. The main goal of this paper is to present an appropriate solution for optimizing the above mentioned characteristics. For this purpose, a comprehensive power loss model of a DC-DC converter is fully developed. Proper models are also demonstrated for assessment of the output voltage ripple and the utilized transformer volume as the bulkiest component in a DC-DC converter. In order to provide a test bed for evaluation of the proposed models, a 50W push-pull DC-DC converter is designed and implemented. Finally, a novel cost function with three assigned weight functions is proposed in order to have a trade-off among the power loss, the output voltage ripple and the utilized transformer volume of the converter. The cost function is optimized for applications in which volume has the highest priority in comparison with power loss and ripple. The optimization results show that the transformer volume can be decreased by up to 51% and this result is verified by experimental results. The developed models and algorithms in this paper can be used for other DC-DC converter topologies with some minor modifications.

• Journal of Biosystems Engineering
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• 제10권2호
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• pp.19-26
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• 1985

This study was carried out to develop a versatile data acquisition/processing system for overall tractor performance utilizing a NEC PC-8001 microcomputer. The data acquisition system measures drawbar pull and power, wheel torque and axle power, ground speed, wheel slip, fuel flow, and engine speed. The system stores hexadecimal data for these variables in memory. Upon completion of each test run, all hexadecimal data stored in memory are recorded on floppy disc. The data processing system reads in the data collected on floppy disc and interprete them using several graphical and statistical techniques. The system uses the same microcomputer and a dot-matrix printer. The data acquisition system has been installed on a GOLDSTAR 500 tractor (2WD, 50 ps). A field study has shown that tractor performance data can be quickly and easily collected. It also appeared that the data processing system can be used to efficiently analyze the collected data. The data acquisition system has some troublesome in mounting and handling on tractor since it uses a general-purpose computer consisting of several components.

• Computers and Concrete
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• 제7권2호
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• pp.191-202
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• 2010

A laboratory investigation was conducted to characterize the constitutive property behavior of Cor-Tuf, an ultra-high-performance composite concrete. Mechanical property tests (hydrostatic compression, unconfined compression (UC), triaxial compression (TXC), unconfined direct pull (DP), uniaxial strain, and uniaxial-strain-load/constant-volumetric-strain tests) were performed on specimens prepared from concrete mixtures with and without steel fibers. From the UC and TXC test results, compression failure surfaces were developed for both sets of specimens. Both failure surfaces exhibited a continuous increase in maximum principal stress difference with increasing confining stress. The DP tests results determined the unconfined tensile strengths of the two mixtures. The tensile strength of each mixture was less than the generally assumed tensile strength for conventional strength concrete, which is 10 percent of the unconfined compressive strength. Both concretes behaved similarly, but Cor-Tuf with steel fibers exhibited slightly greater strength with increased confining pressure, and Cor-Tuf without steel fibers displayed slightly greater compressibility.

• 한국구조물진단유지관리공학회 논문집
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• 제17권5호
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• pp.31-39
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• 2013

본 연구에서는 콘크리트 강도와 앵커의 강도 변화에 따른 앵커시스템의 성능을 평가하였다. 성능평가를 위하여 후 설치 앵커의 한 종류인 Set Anchor를 선정하였다. 동결융해 시험을 통하여 콘크리트의 강도를 감소시켰고, 부식을 통하여 앵커의 강도 감소를 고려하였다. 설치 앵커인 Set Anchor를 동결융해 된 콘크리트와 일반 앵커를 설치하고, 일반 콘크리트에 부식된 앵커를 설치하여 콘크리트 내력에 따른 인발 내력을 고찰 하였다. 각 시험체별로 앵커의 직경, 앵커의 근입 깊이를 변수로 설정하였다. 실험결과 인발 하중을 받는 경우에는 앵커의 직경 및 근입 깊이에 영향이 있는 것으로 나타났다. 인발 실험시 콘크리트 콘 파괴 및 뽑힘파괴 등 콘크리트와 앵커의 내구성에 따라 파괴모드가 다르게 발생하였다. 또한 앵커의 인발 내력을 CCD (Concrete Capacity Design)방법을 사용한 결과와 비교 평가하여 새로운 수정식을 제안하였으며, 수정식을 사용하여 일반 및 동결융해 콘크리트에 설치된 앵커의 인발 내력을 예측 할 수 있었다.

• 한국정보통신학회논문지
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• 제17권10호
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• pp.2359-2368
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• 2013

본 논문에서는 power IC에서 파워가 ON되어있는 동안 입력 신호인 RD(Read) 신호 포트에 glitch와 같은 신호 잡음이 발생하더라도 파워-업(power-up)시 readout된 DOUT 데이터를 유지하면서 다시 읽기 모드로 재진입하지 못하도록 막아주는 IRD(Internal Read Data) 회로를 제안하였다. 그리고 pulsed WL(Word-Line) 구동방식을 사용하여 differential paird eFuse OTP 셀의 read 트랜지스터에 수 십 ${\mu}A$의 DC 전류가 흐르는 것을 방지하여 blowing 안된 eFuse 링크가 EM(Electro-Migration)에 의해 blowing되는 것을 막아주어 신뢰성을 확보하였다. 또한 program-verify-read 모드에서 프로그램된 eFuse 저항의 변동을 고려하여 가변 풀-업 부하(variable pull-up load)를 갖는 센싱 마진 테스트 기능을 수행하는 동시에 프로그램 데이터와 read 데이터를 비교하여 PFb(pass fail bar) 핀으로 비교 결과를 출력하는 회로를 설계하였다. $0.18{\mu}m$ 공정을 이용하여 설계된 8-비트 eFuse OTP IP의 레이아웃 면적은 $189.625{\mu}m{\times}138.850{\mu}m(=0.0263mm^2)$이다.

• 한국해양환경ㆍ에너지학회지
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• 제19권1호
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• pp.7-17
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• 2016

본 연구에서는 대형 부유식 파력-해상풍력 복합발전 구조물의 극한환경 운동 성능에 관한 실험적 연구를 다루고 있다. 대형 부유식 복합발전 구조물에 대한 운동 성능을 평가하기 위하여 1/50 축척비의 모형을 제작하였다. 그리고 설계된 계류선의 사양에 부합하는 계류선 모형을 제작하였고 자유감쇠시험 및 static pull-out 시험을 통하여 검증하였다. 주어진 구조물의 수심을 만족하기 위하여 계류선 테이블을 도입하고 환경조건에 계류판에 따른 환경조건을 확인하였다. 모형시험에서 규칙파 중 운동응답을 확인하고 파랑, 조류, 바람의 복합환경 하중을 적용하여 극한환경 운동성능을 해석하였다. 최대 운동 및, 가속도를 계측하여 운동 안전성을 판단하였고 최대 변위와 계류 하중도 선급기준에 따라 판단하였다. 이로부터 복합발전 구조물의 운동 특성에 대하여 토의하였다.

• 대한의용생체공학회:의공학회지
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• 제38권4호
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• pp.143-152
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• 2017

The main purpose of this research was to examine the EMG characteristics of driver's upper limb and driving performance for operating accelerator and brake pedal by using four types of left hand control devices(Push/Pull, Push/Right angle, Push/Rock, Push/Twist) during simulated driving. The persons with disabilities in the lower extremity have problems in operation of the vehicle because of functional impairments for controlling accelerator and brake pedal. Therefore, if hand control device is used for adaptive driving controls in persons with lower extremity loss, the disabled people could improve their quality of mobility life by driving a car. Twenty subjects were involved in this research to assess driving performance and EMG activities for operating accelerator and brake pedal by using four types of left hand controls in driving simulator. We measured EMG responses of six muscles(posterior deltoid, middle deltoid, biceps, triceps, extensor carpi radialis, and flexor carpi radialis) during pulling and pushing movement with four types of left hand controls for acceleration and braking. STISim Drive 3 program was used for evaluation test of four types of left hand control devices in straight lane course for time to reach target speed and brake reaction time. While operating the four types of left hand controls for acceleration, EMG activities of posterior deltoid in normal subjects were significantly increased(p < 0.05) compared to the disabled subjects. It was also found that EMG responses of triceps and posterior deltoid were significantly increased(p < 0.05) when using the Push/Right angle type than Push/Pull type. While operating the four types of left hand controls for braking, EMG activities of flexor carpi radialis and triceps in subjects with disability were significantly increased(p < 0.05) compared to the normal subjects. It was shown that muscle responses of posterior deltoid, middle deltoid and triceps were significantly increased when using the Push/Right angle type than Push/Rock type. Time to reach target speed and brake reaction time in subjects with disability was increased by 2.5% and 4.6% on average compared to normal subjects. The person with disabilities showed a tendency to relatively slow performance in acceleration at the straight lane course.

• 산경연구논집
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• 제10권1호
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• pp.59-67
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• 2019

Purpose - The Millennial Generation, which grew in the wake of the spread of the Internet and rapid changes in the media environment, is rapidly moving from the traditional broadcasting environment to the Internet-broadcasting environment in terms of content acceptance. With the emergence of UGC (User-generated content), the change in the status of single-person content creators enables the growth of multi-channel networks (MCN), a new content-distribution platform and an agency concept for single creators. Youtube-based MCN produces multiple single star producers and casts and provides its own video series through Youtube. It is also emerging as a major M&A target for global media providers in terms of providing content to a wide range of consumers with the same interests and consumption characteristics. In addition, for the Millennials generation, which are part of their lives, MCN is becoming the most suitable media for TGIF (Twitter, Google, i-phone, Facebook). Accordingly, this study defines newly emerging MCNs and analyzes the factors for accepting MCN-produced content based on the push-pull-mooring (PPM) model. Research design, data, and methodology - An empirical analysis is performed through a questionnaire survey. For this purpose, 204 people who have experience of watching MCN were studied. Collected data is processed through analysis of a structural equation model using R to test the hypothesis. Results - For the MCN service to become an alternative to existing media, it is necessary to continuously promote cultural diversity and diversity of attempts that conventional media cannot provide. It is the attractiveness of the alternative that has the greatest influence on the intention to switch to a MCN service. When we look at MCN content so far, certain patterns such as game progress, introduction, food, and chat rooms have already appeared. We need to overcome this and develop a completely new conceptual content that we have never seen before. This requires a more generous viewer perception of the topics covered. For diversity, linguistic and verbal violence should be tolerant in common sense to provide a foundation for securing cultural diversity. Conclusions - In this study, we tried to develop a comprehensive approach to the substitution effect of MCN. In terms of academic achievement, the PPM model is used to enhance the utilization of media and broadcasting. Practical implications are to provide an analytical framework for verifying alternative or complementary effects when viewers switch to MCN.