• The Mathematical Education
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• v.60 no.2
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• pp.159-172
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• 2021

The purpose of this study is to compare and analyze the effects of physical manipulative and exploratory geometry software on the spatial sense for 5^th grade elementary school students in learning nets. For this purpose, ton experimental group used Geofix, an operational learning tool, and the experimental group used Cabri 3D, an exploratory geometry software to learn the nets of solids. The comparison group was learned by worksheet only without any manipulative or software. Spatial sense tests were conducted before and after to determine the level, and eye tracking were used to analyze the strategies of students in solving nets problems. As a result, it was confirmed that the using Geofix group was the most effective for the spatial sense, and Cabri 3D could also be a good tool for learning the nets of solids. In addition, after learning the nets of solids, the analytical strategy, which was the most effective strategy for students' solving strategies, increased. In the process of solving spatial tasks such as the spatial sense tasks, eye tracking technology become a very useful tool for exploring students' strategies, so it is expected that objective and useful data will be collected through more active use in the future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.12
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• pp.3109-3120
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• 1996

SDL has been standardized to specify behavioral aspects of communication systems based on the formal description technique, and it is powerful and user friendly in the sense of supporting human communication and understanding, formal analysis andcomparison of behaviors, alternative implementations and design optimization, and its structural decomposition. However, SDL is not sufficient for an efficient handing of entrire system descriptions because the communication systems are generally very complex, and composed from the various interactions among sub-systems. Also, it is very difficult to explicitly verify dynamic views such as liveness and reachability. it leads the demands on analysis scheme to verify dynamic behaviros of specified systems. This paper presents modeling concepts of Petri Nets from SDL and transformation rules to Numerical Petri Nets to provide efficient technqiques for verification of dynamic behaviors, and proposes the reachability garaph that is able to trace all reachable states of a modeled system and reduce an information loss on the reachability tree.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.462-463
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• 2008

This paper proposes a method for dynamic output-feedback controller design for stochastic time-delay systems. Based on recent results on time-delay systems control, a tractable and delay-dependent design condition is proposed, which provides a dynamic output-feedback controller to render the closed-loop stochastic time-delay systems to be asymptotically stable in the mean-square sense. The feasibility problem of the proposed condition is recast into a cone complementarity problem. An algorithm adopting cone complementarity linearization is presented to solve the resulting problem.

• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.157-160
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• 1995

Neural networks potentially offer a general framework for modeling and control of nonlinear systems. The conventional neural network models are a parody of biological neural structures, and have very slow learning. In order to emulate some, dynamic functions, such as learning and adaption, and to better reflect the dynamics of biological neurons, M.M.Gupta and D.H.Rao have developed a 'dynamic neural model'(DNU). Proposed neural unit model is to introduce some dynamics to the neuron transfer function, such that the neuron activity depends on internal states. Numerical examples are presented for a model system. Those case studies showed that the proposed DNU is so useful in practical sense.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.199-199
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• 2000

Most of linear time-varying(LTV) systems except special cases have no general solution for the dynamic equations. Thus, it is difficult to design time-varying controllers in analytic ways, and other control design approaches such as robust control have been applied to control design for uncertain LTI systems which are the approximation of LTV systems have been generally used instead. A robust control method such as quantitative feedback theory(QFT) has an advantage of guaranteeing the stability and the performance specification against plant parameter uncertainties in frozen time sense. However, if these methods are applied to the approximated linear time-invariant(LTI) plants which have large uncertainty, the designed control will be constructed in complicated forms and usually not suitable for fast dynamic performance. In this paper, as a method to enhance the fast dynamic performance, the approximated uncertainty of time-varying parameters are reduced by the proposed QFT parameter-scheduling control design based on radial basis function (RBF) networks for LTV systems with bounded time-varying parameters.

• Journal of applied mathematics & informatics
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• v.39 no.1_2
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• pp.197-214
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• 2021

In this paper, we have studied dynamics of fractional order mathematical model of malaria transmission for two groups of human population say semi-immune and non-immune along with growing stages of mosquito vector. The present fractional order mathematical model is the extension of integer order mathematical model proposed by Ousmane Koutou et al. For this study, Atangana-Baleanu fractional order derivative in Caputo sense has been implemented. In the view of memory effect of fractional derivative, this model has been found more realistic than integer order model of malaria and helps to understand dynamical behaviour of malaria epidemic in depth. We have analysed the proposed model for two precisely defined set of parameters and initial value conditions. The uniqueness and existence of present model has been proved by Lipschitz conditions and fixed point theorem. Generalised Euler method is used to analyse numerical results. It is observed that this model is more dynamic as we have considered all classes of human population and mosquito vector to analyse the dynamics of malaria.

• PNF and Movement
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• v.21 no.2
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• pp.265-272
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• 2023

Purpose: The purpose of this study was to investigate tactile sense perception of the lower extremities according to physical function in children with spastic cerebral palsy. Methods: This study was conducted on 15 children diagnosed with spastic cerebral palsy. Physical function measurement items included dynamic balance ability, gross motor function level, and lower extremity ankle spasticity. The lower extremity tactile sensation uses a monofilament to measure the sole of the first metatarsal head, the sole of the fifth metatarsal head, the heel, the anterior part of the shin midway between the patella and the ankle joint, the kneecap, the upper anterior iliac spine, and the knee. A total of six measurements were taken in the mid-femoral region of the bone. Spearman correlation analysis was performed to determine the degree of body function and lower extremity tactile perception. Results: As the physical function of children with spastic cerebral palsy deteriorated, there was a decrease in tactile sensation in the thigh area corresponding to the proximal lower extremity. (p <.05). Conclusion: Children with spastic cerebral palsy and poor physical function have sensory loss not only in the distal part but also in the proximal part, so a treatment approach that recognizes and improves it is necessary.

• The Journal of Korean Physical Therapy
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• v.34 no.6
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• pp.312-316
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• 2022

Purpose: The purpose of this study was to investigate the effect of a kettlebell complex program according to the support surface on the lower extremity muscle activity and balance of baseball players. Methods: The participants were divided into two groups; unstable support surface group 1 (11 people) performed the kettlebell complex program on an unstable support surface, and stable support surface group 2 (10 people) performed the kettlebell complex program on a stable support surface. Muscle activity was measured by surface electromyography. Dynamic balance was measured with a balance-measuring equipment. A paired t-test was used to compare groups before and after the experiment. An independent t-test was performed to determine the difference in the degree of change between the two groups before and after the experiment. Results: The intragroup comparison between stable support surface group 1 and 2 showed significant differences in muscle activity and sense of balance. In the comparison between the groups, the difference in muscle activity in unstable support surface group1 was significant in the biceps femoris and rectus femoris muscles, and significant differences were also found in the sense of balance. Conclusion: These results suggest that a kettlebell exercise on an unstable support surface is more effective in improving muscle activity and sense of balance than a kettlebell exercise on a stable support surface.

• PNF and Movement
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• v.18 no.2
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• pp.173-182
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• 2020

Purpose: The purpose of the study was to investigate the effects of visual feedback exercise (VFE), sandal exercise (SE), and thera-band exercise (TE) on people with functional ankle instability. Methods: The 45 study participants were divided into three groups of 15. In the VFE group, participants performed short-foot exercises using visual feedback; the SE group performed sandal exercises, and the TE group performed thera-band exercises. Over a period of 8 consecutive weeks, the experimental groups exercised for 15 minutes per session, four times per week. Balance was measured using the Biodex Balance System for dynamic balance ability (overall balance index [OBI], mediolateral balance index [MBI], and anterioposterior balance index [ABI]). Vibration threshold sense (VTS) was assessed using a vibratory sensory analyzer. Ankle muscular strength was measured using the Biodex 4 Pro. The main outcome measures were assessed at baseline and after 8 weeks of training. Results: Significant improvements in dynamic balance were noted in all three groups (p < 0.05). Significant improvements in VTS and muscular strength were also noted in the VFE and TE groups but not in the SE group (p < 0.05). Conclusion: Appropriate environmental and situational mediation may be of great clinical significance for patients suffering from chronic ankle instability. It is hoped that the findings will inform a program for prevention of ankle instability.

• The KIPS Transactions:PartB
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• v.16B no.4
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• pp.327-331
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• 2009

In fuzzy logic, aggregating uncertainties is generally achieved by means of operators such as t-norms and t-conorms. However, existing aggregation operators have some disadvantages as follows : First, they are situation-independent. Thus, they may not be properly applied to dynamic aggregation process. Second, they do not give an intuitional sense to decision making process. To solve these problems, we propose a new $\varepsilon$-AMDA (Aggregation based on the fuzzy Multidimensional Decision Analysis) algorithm to reflect degrees of strength for option i (i = 1, 2, ..., n) in the decision making process. The $\varepsilon$-AMDA algorithm makes adaptive aggregation results between min (the most weakness for an option) and max (the most strength for an option) according to the values of the parameter representing degrees of strength for an option. In this respect, it may be applied to dynamic aggregation process. In addition, it provides a mechanism of the fuzzy multidimensional decision analysis for decision making, and gives an intuitional sense to decision making process. Thus, the proposed method aids the decision maker to get a suitable decision according to the degrees of strength for options (or alternatives).