• 한국정밀공학회지
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• 제14권2호
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• pp.129-135
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• 1997

Experimental studies have been carried out to obtain uniform cups by one operation of backward extrusion. A lot of factors on dimensional accuracy of backward extruded cups are billet material, billet shape, punch shape, punch velocity, geometry of tool, tool material, and lubrication etc. In manufacturing cup-shaped parts by backward extrusion, it is very important to design the initial billet shape or the preform. The objective of this paper is to find that the shape of the initial billet is related to dimensional accuracy and also to manufacture the more accurate product simultaneously reducing the loss of material as forming the shape of the initial billet by means of upsetting.

• 컴퓨터교육학회논문지
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• 제22권3호
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• pp.113-121
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• 2019

본 연구에서는 교사들의 소프트웨어 교육 및 정보 교육 수업 전문성 함양을 위하여 백워드 설계를 기반으로 TPACK-P 교육 프로그램에 백워드 설계의 이해에 대한 내용을 포함하여 설계하였다. 이를 비정보과 교사를 대상으로 32시간의 교사 연수를 실시한 결과, 교사들은 SW교육 교수 효능감 측정도구(SE-TEBI)의 사후 검사 결과가 사전 검사에 비해 SE-TE 전체 값(t=-3.541, p<.01) 및 하위 범주인 개인효능(t=-3.559, p<.01), 결과기대(t=-2.258, p<.05)가 모두 통계적으로 유의하게 상승하였음을 확인하였다. 따라서 본 연구에서 개발한 백워드 설계 기반 TPACK-P 교육 프로그램은 교사들의 소프트웨어 교육 및 정보 교육에 대한 수업 전문성을 높이는데 도움이 된다고 해석할 수 있다. 하지만 검사 결과 전반적으로 교사들의 개인효능(PSETE)이 결과기대(SEOE)보다 낮은 경향을 보이는데, 이는 수업에 대한 자신감의 부족으로 해석된다. 따라서 추후 연구에서는 교사들의 수업 자신감을 촉진할 수 있는 교사 교육 프로그램의 개발이 요구된다.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2001년도 유체기계 연구개발 발표회 논문집
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• pp.48-53
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• 2001

A centrifugal fan design code was developed and included in $DasignFan^{TM}$. This program generates forward -curved and backward-curved bladed centrifugal fan data. With the inverse design concept used in the code, the period of designing a fm, which has given aerodynamic performance with minimal acoustic noise, is significantly shortened.. A centrifugal fan design code, developed in this study and included in $DasignFan^{TM}$, predicts the aerodynamic performance by using mean-line analysis and various loss models. In the period of design a lift force distribution between pressure side and suction side of blade is calculated. And then it is used to calculate steady loading noise from the impeller.

• 대한물리의학회지
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• 제13권2호
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• pp.53-60
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• 2018

PURPOSE: This study aimed to identify the effect of a backward walking exercise using a mirror on balance and gait in patients with stroke. METHODS: Twenty subjects with post-stroke hemiparesis volunteered to participate in this study. The experimental and control groups performed backward walking exercise plus conventional therapy or conventional physical therapy, respectively, for 6 weeks. Assessment instruments included the Berg Balance Scale (BBS), timed up and go test (TUG), and 10-m walking test (10MWT). Evaluation was performed before and after the 6-week training period. We conducted a paired t-test to compare the within-group changes before and after the intervention. An independent t-test was used to compare between-group differences. The statistical significance level was set at ${\alpha}=.05$ for all variables. RESULTS: The experimental group showed a significant within-group change in the BBS, TUG, and 10MWT (p<.05). The control group also showed a significant change (p<.05). A significant difference was observed between the experimental and control groups with regard to changes in the BBS, TUG, and 10MWT results after the interventions (p<.05). CONCLUSION: This study demonstrated that backward walking exercise using a mirror may be valuable for future research. Further studies with a wider range of pathology and longer experiment duration are required to validate the results of the present study.

• 전자공학회논문지B
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• 제33B권9호
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• pp.49-61
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• 1996

Back-propagation(BP) algorithm needs a lot of time to train the artificial neural network (ANN) to get high accuracy level in classification tasks. So there have been extensive researches to process back-propagation algorithm on parallel processors. This paper prsents a linear systolic array which calculates forward-backward propagation of BP algorithm at the same time using effective space-time transformation and PE structure. First, we analyze data flow of forwared and backward propagations and then, represent the BP algorithm into data dapendency graph (DG) which shows parallelism inherent in the BP algorithm. Next, apply space-time transformation on the DG of ANN is turn with orthogonal direction projection. By doing so, we can get a snakelike systolic array. Also we calculate the interval of input for parallel processing, calculate the indices to make the right datas be used at the right PE when forward and bvackward propagations are processed in the same PE. And then verify the correctness of output when forward and backward propagations are executed at the same time. By doing so, the proposed system maximizes parallelism of BP algorithm, minimizes th enumber of PEs. And it reduces the execution time by 2 times through making idle PEs participate in forward-backward propagation at the same time.

• 한국IT서비스학회지
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• 제9권3호
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• pp.123-144
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• 2010

As knowledge becomes a critical success factor of companies nowadays, lots of rule-based systems have been and are being developed to support their activities. Large number of rule-based systems serve as Web sites to advise, or recommend their customers. They usually use a backward chaining inference algorithm based on backtrack to implement those interactive Web-enabled rule-based systems. However, when the users like customers are using these systems interactively, it happens frequently where the users do not know some of the answers for the questions from the rule-based systems. We are going to design a backward chaining inference methodology considering unknown facts based on backtrack technique. Firstly, we review exact and inexact reasoning. After that, we develop a backward chaining inference algorithm for exact reasoning based on backtrack, and then, extend the algorithm so that it can consider unknown facts and reduce its search space. The algorithm speeded-up inference and decreased interaction time with users by eliminating unnecessary questions and answers. We expect that the Web-enabled rule-based systems implemented by our methodology would improve users' satisfaction and make companies' competitiveness.

• Physical Therapy Rehabilitation Science
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• 제7권2호
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• pp.83-87
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• 2018

Objective: The purpose of this study was to investigate the relationship between heart rate (HR), self-awareness of exercise intensity (rating of perceived exertion, RPE), and 5-meter walk test (5MWT) of persons affected by stroke during backward walking according to the preferred stride frequency (PSF), PSF+3 and PSF+6 conditions. Design: Cross-sectional study. Methods: A total of 11 persons with stroke (9 males, 2 females) participated voluntarily. All patients underwent backward walking under the PSF, PSF+3, and PSF+6 conditions in underwater and ground environments, and each condition was performed for 5 minutes. The HR, RPE, and walking speeds were measured during walking, and the measured values from underwater and ground environments were compared. Results: The HR and RPE in the ground environment were significantly increased (p<0.05), and although the 5MWT showed an increase in speed, it was not significant. The HR and RPE in the underwater environment were also significantly increased (p<0.05), however, although the 5MWT results was increased, it was not significant. The HR and RPE were significantly increased in the PSF+6 condition (p<0.05). Conclusions: The results of this study showed that backward gait training underwater can provide an appropriate exercise intensity for stroke survivors and suggests that exercises performed in an underwater environment is more effective compared to the ground environment.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.84-87
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• 1999

This paper presents a preform design method that combines the analytic method and inference of known knowledge with neural network. The analytic method is a finite element method that is used to simulate backward extrusion with pre-defined process parameters. The multi-layer network and back-propagation algorithm are utilized to learn the training examples from the simulation results. The design procedures are utilized to learn the training examples from the simulation results. The design procedures are two methods the first the neural network infer the deformed shape from the pre-defined processes parameters. The other the network infer the processes parameters from deformed shape. Especially the latest method is very useful to design the preform From the desired feature it is possible to determine the processes parameters such as friction stroke and tooling geometry. The proposed method is useful for shop floor to decide the processes parameters and preform shapes for producing sound product.

• Journal of Advanced Marine Engineering and Technology
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• 제23권5호
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• pp.678-685
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• 1999

A UBET program is developed for determining flash the optimum sizes of preform and initial billet in plane-strain closed-die forging. The program consists of forward and backward tracing processes. In the forward program, flash, die filling and forging load are predicted. In backward tracing process the optimum dimensions of initial billet and preform are determined from the final-shape data based on flash design. Experiments are carried out with pure plasticine billets ar room temperature. The theoretical predictions of forging load and flow pattern are in good agree-ment with the experimental results.

• 대한지구과학교육학회지
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• 제13권2호
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• pp.147-161
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• 2020

이 연구는 초등학생들의 천문단원에 대한 심층적인 이해를 돕고자 백워드 설계 2.0을 활용해 단원을 설계하고 적용해봄으로써 과학 학업성취도, 수행평가, 과학 수업 만족도의 효과를 확인하고자 하였다. 연구 결과, 과학 학업성취도 검사에서는 통계적으로 유의미한 차이가 없었지만, 실험집단의 평균점수가 향상되었다. 수행평가 점수 결과, 통계적으로 유의미한 차이가 있었는데, 이는 과정 중심 평가를 통해 피드백이 잘 제공되면서 심층적인 이해를 도왔기 때문이다. 과학 수업 만족도 검사 결과, 과학교사 영역을 제외한 과학교육 과정 영역과 교우 관계 영역에서는 통계적으로 유의미한 차이가 있었다. 이는 철저한 성취기준 분석을 통해 차별화된 과학과 교육과정을 설계하였으며, 성취기준 도달을 위해 다양한 학생중심의 교수·방법을 구현했기 때문이다. 이 연구를 통해 초등과학 수업에서 백워드 설계 2.0이 학습자에게 미치는 영향에 주목하고, 백워드 설계 2.0을 현장에서 효과적으로 적용할 수 있는 방법을 찾는 데 도움이 되길 기대해 본다.