• Journal of the Korean Society for Precision Engineering
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• v.14 no.2
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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.

• The Journal of Korean Association of Computer Education
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• v.22 no.3
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• pp.113-121
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• 2019

The purpose of this study is to develop TPACK-P teachers' training program based on backward design included understanding of backward design principles in order to enhance teachers' professionalism of software education and informatics education. This teachers' training program was conducted for non-informatics teachers in 32 hours. As a results, teachers showed that post-test result of SE-TEBI was higher than pre-test and the t-test results showed that the total value of SE-TE was t=-3.541(p< .01), subscale PSETE was t=-3.559( p< .01) and SEOE was t=-2.258(p< .05). Therefore, we demonstrate that it helps improve the teaching professionalism of teachers. However, as a result of the test, teachers' PSETE tend to be lower in SEOE, which is interpreted as a lack of confidence in the lessons. Therefore, in further study, it is necessary to develop a teacher education program that can promote the confidence of teachers.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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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.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.2
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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.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.9
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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.

• Journal of Information Technology Services
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• v.9 no.3
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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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• v.7 no.2
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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.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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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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• v.23 no.5
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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.

• Journal of the Korean Society of Earth Science Education
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• v.13 no.2
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• pp.147-161
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• 2020

In order to help elementary students understand the astronomical unit in depth, this study applied backward design 2.0 to check the effect on students' science academic achievement, performance evaluation, and science class satisfaction. As a result of the study, there was no statistically significant difference in the science achievement test, but the average score of the experimental group has improved. As a result of the performance evaluation test, there was a statistically significant difference because the feedback was well provided through the process-focused assessment and it helped in-depth understanding. As a result of the science class satisfaction test, there was a statistically significant difference in the areas of science curriculum and peer relation except for the science teacher area. This is because a differentiated science curriculum was designed through analysis of achievement standards, and various teaching methods of student-centered were implemented to reach achievement standards. We hope this study will focus on the impact of backward design 2.0 on learners in elementary science classes and help find ways to effectively apply backward design 2.0 in the field.