• ETRI Journal
• /
• 제25권3호
• /
• pp.187-194
• /
• 2003

Delay testing has become an area of focus in the field of digital circuits as the speed and density of circuits have greatly improved. This paper proposes a new scan flip-flop and test algorithm to overcome some of the problems in delay testing. In the proposed test algorithm, the second test pattern is generated by scan justification, and the first test pattern is processed by functional justification. In the conventional functional justification, it is hard to generate the proper second test pattern because it uses a combinational circuit for the pattern. The proposed scan justification has the advantage of easily generating the second test pattern by direct justification from the scan. To implement our scheme, we devised a new scan in which the slave latch is bypassed by an additional latch to allow the slave to hold its state while a new pattern is scanned in. Experimental results on ISCAS'89 benchmark circuits show that the number of testable paths can be increased by about 45 % over the conventional functional justification.

• 대한전기학회논문지:전력기술부문A
• /
• 제48권9호
• /
• pp.1161-1166
• /
• 1999

Delay testing has become highlighted in the field of digital circuits as the speed and the density of the circuits improve greatly. However, delay faults in sequential circuits cannot be detected easily due to the existence of state registers. To overcome this difficulty a new scan filp-flop is devised which can be used for both stuck-at testing and delay testing. In addition, the new scan flip-flop can be applied to both the existing functional justification method and the newly-developed reverse functional justification method which uses scan flip-flops as storing the second test patterns rather than the first test patterns. Experimental results on ISCAS 89 benchmark circuits show that the number of testable paths can be increased by about 10% on the average.

• 한국초등과학교육학회지:초등과학교육
• /
• 제24권5호특별호
• /
• pp.518-530
• /
• 2005

The purpose of this study was to investigate the characteristics of pre-service primary teachers' justifying their hypotheses about the brightness of electric bulbs. They conducted their experiments and wrote their experimental results and ideas on their worksheets. The worksheets for generating and evaluating scientific hypothesis were analyzed. Most of them generated the consumption hypothesis and designed the experiments to confirm their hypotheses or directly measure without the change of experimental conditions. The responses for valid experimental designs were $74\%$ of total responses. The $62\%$ of total responses was valid prediction for experimental results. The $60\%$ of pre-service teachers described the experimental results correctly. But other teachers described the biased results or inappropriate results. The $54\%$ of them refuted hypotheses and the $36\%$ confirmed their hypotheses. The theory-based responses were $51\%$ and the evidence-based responses were $47\%$. The $64\%$ of them proposed the possibility of the alternative hypothesis after testing their hypotheses. This study also discussed the implications of these findings for teaching and Loaming in science education.

• Child Health Nursing Research
• /
• 제24권4호
• /
• pp.443-453
• /
• 2018

Purpose: This study was describes the development and implementation a sex education program with a blended learning method for university students. Methods: Sixty-eight university students were recruited either to the experimental group (n=35) or the control group (n=33). This program was developed based on the analysis, design, development, implementation, and evaluation model. The analysis phase consisted of a literature review, focus group interview, expert consultations, and target group survey. In addition, learning objectives and structure were designed, and a printed text-book, presentation slides, cross-word puzzle, and debate topics were developed. In the implementation phase, the program was conducted 3 times over the course of 3 weeks. The evaluation phase involved verification of the effects of the program on sex-related knowledge, sexual autonomy, and justification of violence, as well as an assessment of satisfaction with the program. Results: The experimental group had significantly higher scores on sex-related knowledge (t=5.47, p<.001), sexual autonomy (t=2.40, p=.019), and justification of violence (t=2.52, p=.015) than the control group. Conclusion: The results indicate that this sex education program with blended learning was effective in meeting the needs of university students and can be widely used in this context.

• 한국학교수학회논문집
• /
• 제10권2호
• /
• pp.207-219
• /
• 2007

수학에서 중요한 부분인 증명을 학생들은 어려워한다. 증명을 테크놀로지를 이용하여 대수적 시각화 자료와 특수화된 시각화 자료를 만들어 지도하였다. 그러나 테크놀로지를 활용한 대수적 시각화 자료의 표현상 오류에 의하여, 학생들이 경험적 인식을 가지지 못하여 경험적 정당화를 하는데 어려움이 있었다. 테크놀로지를 활용한 특수화된 시각화 자료는 고정된 경우에만 성립하기 때문에 수학적 사고의 확장을 제한하였다. 이를 해결하기 위해서 테크놀로지를 활용하여 자체 제작한 중학교 3학년 기하단원의 기하적 시각화 자료와 일반화된 시각화 자료를 통해 학생들에게 경험적 인식을 심어주어 경험적 정당화를 시켰으며, 수학적 사고의 향상을 관찰할 수 있었다.

• 품질경영학회지
• /
• 제21권1호
• /
• pp.96-107
• /
• 1993

In parameter design Taguchi analyzed a statistic which he called signal-to-noise(SN) ratio by using the experimental design technique. However he gave no justification for using SN ratios in the optimization procedure of parameter design. In this paper we discuss the validity of such SN ratios as proper statistics to be analyzed in parameter design. Moreover, using the real empirical data we examine the appropriateness of SN ratios, and we explain how transformation technique can be applied in parameter design as an alternative method of analysis.

• 한국수학교육학회지시리즈A:수학교육
• /
• 제43권4호
• /
• pp.381-390
• /
• 2004

In this study, we conceptualized the ‘preformal proof’, which is a transitive level of proof from the experimental and inductive justification to the formalized mathematical proof. We investigated concrete features of the preformal proof in the historico-genetic and the didactical situations. The preformal proof can get the generality of the contents of proof, which makes a distinction from the experimental proof. And we can draw a distinction between the preformal and formal proof, in point that the preformal proof heads for the reality-oriented objects and does not use the formal language.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회B
• /
• pp.2088-2093
• /
• 2008

In this study, flow field measurement of the Pebble Bed Reactor(PBR) for the High Temperature Gas-cooled Reactor(HTGR) was performed. Large number of pebbles in the core of PBR provides complicated flow channel. Due to the complicated geometries, numerical analysis has been intensively made rather than experimental observation. However, the justification of computational simulation by the experimental study is crucial to develop solid analysis of design method. In the present study, a wind tunnel installed with pebbles stacked was constructed and equipped with the Particle Image Velocimetry(PIV). We designed the system scaled up to realize the room temperature condition according to the similarity. The PIV observation gave us stagnation points, low speed region so that the suspected high temperature region can be identified. With the further supplementary experimental works, the present system may produce valuable data to justify the Computational Fluid Dynamics(CFD) simulation method.

• 한국전산유체공학회지
• /
• 제19권2호
• /
• pp.30-39
• /
• 2014

We report in this paper the analysis of the motion of a needle and a spring in a viscous fluid under the influence of gravitational force. Lateral shift as well as vertical motion of a needle falling in a viscous fluid has been observed from a simple experiment. We also observed the combined rotation and translation of a falling spring. The trajectory and velocity of the falling needle and the spring were obtained by using an image processing technique. We also conducted numerical simulation for both problems. For the falling-needle problem, we employed a theory; but it turns out that significant correction is required for the solutions to match the numerical and experimental data. For the falling spring problem various theoretical formula were tested for their justification, but none of the existing theories can successfully predict the numerical and experimental results.

• Smart Structures and Systems
• /
• 제24권3호
• /
• pp.361-377
• /
• 2019

The stiffness of shape memory alloy (SMA) spring while in actuation is represented by an empirical model that is derived from the logistic differential equation. This model correlates the stiffness to the alloy temperature and the functionality of SMA spring as active variable stiffness actuator (VSA) is analyzed based on factors that are the input conditions (activation current, duty cycle and excitation frequency) and operating conditions (pre-stress and mechanical connection). The model parameters are estimated by adopting the nonlinear least square method, henceforth, the model is validated experimentally. The average correlation factor of 0.95 between the model response and experimental results validates the proposed model. In furtherance, the justification is augmented from the comparison with existing stiffness models (logistic curve model and polynomial model). The important distinction from several observations regarding the comparison of the model prediction with the experimental states that it is more superior, flexible and adaptable than the existing. The nature of stiffness variation in the SMA spring is assessed also from the Dynamic Mechanical Thermal Analysis (DMTA), which as well proves the proposal. This model advances the ability to use SMA integrated mechanism for enhanced variable stiffness actuation. The investigation proves that the stiffness of SMA spring may be altered under controlled conditions.