• 한국초등과학교육학회지:초등과학교육
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• 제37권3호
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• pp.254-266
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• 2018

The aim of this study is to analyze STEAM lessons focused on the learner's learning. This study was conducted on 4th-graders in Y city, Kyung-gi province. The lessons were based on a joint teaching plan for students through the teacher learning community (TLC) with three teachers from the same school. Each of the three classes that conducted the class was selected and analyzed as the main center of observation by three students. The conclusions from this study are as follows: First, we identified that different levels of learners are learning in STEAM lessons through a learner-centered class analysis. Some students arrived on their own by taking the initiative in class, others by consulting with a group of friends, and others needed active teacher guidance to learn. Second, Depending on the level and characteristics of the students, some learning criteria were not reached. Some students need guidance at a glance level, and others need individually instructed or guided activities. Teachers need to keep an eye out for students and give them an appropriate level of guidance during class. In STEAM lessons, it appears that students of different levels and characteristics can immerse themselves in their own way, as well as the clear guidance of activity for their students.

• 정보교육학회논문지
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• 제2권2호
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• pp.209-214
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• 1998

컴퓨터 하드웨어의 발전과 초고속의 네트워크의 출현으로 지리적으로는 떨어져 있지만 컴퓨터 네트워크로 연결되어 있는 교사와 학생간에 동기식 학습이 가능하게 되었다. 전통적인 원격 교육과 비교하여 볼 때, 이러한 학습은 매우 높은 수준의 상호작용과 상호 협력을 제공하지만 전통적인 교실에서의 수업과 비교하여 볼 경우에는 다음과 같은 매우 중대한 결점들을 지니고 있다. 오늘날의 동기식 학습 시스템은 오디오, 비디오, 문서 편집을 제공하는 비디오 컨퍼런싱 기술에 주로 의존하고 있으며, 교수 과정의 조절, 손을 드는 행위, 지적 표시 등과 같은 특별한 교수 방법은 크게 고려하지 않고 있다. 이에 대두된 개념이 공유 화이트보드이다. 화이트보드는 전통적인 칠판의 전자적인 대체물로 이를 통해 원격 학습에 임하는 교사와 학생들이 전통적인 교실의 칠판의 이점을 취할 수 있게 된다. 따라서 본 논문에서는 화이트보드 구현시 고려 사항인 시스템 구조와 동시성 제어 방법에 대해 다양하게 살펴본다.

• 한국소음진동공학회논문집
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• 제23권5호
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• pp.438-444
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• 2013

This paper presents the replication of a desired vibration response by iterative learning control (ILC) system for a vibration motion replication actuator. The vibration motion replication actuator has parameter uncertainties including system nonlinearity and joint nonlinearity. Vehicle manufacturers worldwide are increasingly relying on road simulation facilities that put simulated loads and stresses on vehicles and subassemblies in order to reduce development time. Road simulation algorithm is the key point of developing road simulation system. With the rapid progress of digital signal processing technology, more complex control algorithms including iterative learning control can be utilized. In this paper, ILC algorithm was utilized to produce simultaneously the six channels of desired responses using the Stewart platform composed of six linear electro-magnetic actuators with Halbach magnet array. The convergence rate and accuracy showed reasonable results to meet the requirement. It shows that the algorithm is acceptable to replicate multi-channel vibration responses.

• 한국수학교육학회지시리즈A:수학교육
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• 제53권2호
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• pp.201-217
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• 2014

This research has an intention of developing a professional development program. We proposed an alternative mathematics teacher training model based on the situated learning theory, community of practice, and reflective practitioner. The developed mathematics teacher professional development program recruited participation unit that was consisted of 3 or 4 teachers in same school and total of 28 teachers from 9 schools. Also, there were 18 mentors to support each school. In this sense, it can be called multi-tired teacher community professional development program. Through the program, the teachers improve their teaching competency. Also, the operation ability of teacher learning community was improved. Learning community culture has been formed in each school. It shows ability that the explorative learning community can be operated voluntarily although the program finished. Furthermore, community shared corporate responsibility about open class. They recognize open class as a new method to improve community teaching ability than a tool to evaluate individual teaching ability.

• 로봇학회논문지
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• 제16권2호
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• pp.137-146
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• 2021

When controlling manipulator, degree of freedom is lost in singularity so specific joint velocity does not propagate to the end effector. In addition, control problem occurs because jacobian inverse matrix can not be calculated. To avoid singularity, we apply Deep Deterministic Policy Gradient(DDPG), algorithm of reinforcement learning that rewards behavior according to actions then determines high-reward actions in simulation. DDPG uses off-policy that uses 𝝐-greedy policy for selecting action of current time step and greed policy for the next step. In the simulation, learning is given by negative reward when moving near singulairty, and positive reward when moving away from the singularity and moving to target point. The reward equation consists of distance to target point and singularity, manipulability, and arrival flag. Dual arm manipulators hold long rod at the same time and conduct experiments to avoid singularity by simulated path. In the learning process, if object to be avoided is set as a space rather than point, it is expected that avoidance of obstacles will be possible in future research.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권11호
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• pp.3780-3797
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• 2022

The estimation of radio map (RM) is a fundamental and critical task for the network planning and optimization performance of mobile communication. In this paper, a RM estimation method is proposed based on a deep dual learning structure. This method can simultaneously and accurately reconstruct the urban building map (UBM) and estimate the RM of the whole cell by only part of the measured reference signal receiving power (RSRP). Our proposed method implements UBM reconstruction task and RM estimation task by constructing a dual U-Net-based structure, which is named RadioCycle. RadioCycle jointly trains two symmetric generators of the dual structure. Further, to solve the problem of interference negative transfer in generators trained jointly for two different tasks, RadioCycle introduces a dynamic weighted averaging method to dynamically balance the learning rate of these two generators in the joint training. Eventually, the experiments demonstrate that on the UBM reconstruction task, RadioCycle achieves an F1 score of 0.950, and on the RM estimation task, RadioCycle achieves a root mean square error of 0.069. Therefore, RadioCycle can estimate both the RM and the UBM in a cell with measured RSRP for only 20% of the whole cell.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권9호
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• pp.2764-2781
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• 2024

Federated learning (FL) has been proposed as an emerging distributed machine learning framework, which lowers the risk of privacy leakage by training models without uploading original data. Therefore, it has been widely utilized in the Industrial Internet of Things (IIoT). Despite this, FL still faces challenges including the non-independent identically distributed (Non-IID) data and heterogeneity of devices, which may cause difficulties in model convergence. To address these issues, a local surrogate function is initially constructed for each device to ensure a smooth decline in global loss. Subsequently, aiming to minimize the system energy consumption, an FL approach for joint CPU frequency control and bandwidth allocation, called FCBAFL is proposed. Specifically, the maximum delay of a single round is first treated as a uniform delay constraint, and a limited-memory Broyden-Fletcher-Goldfarb-Shanno bounded (L-BFGS-B) algorithm is employed to find the optimal bandwidth allocation with a fixed CPU frequency. Following that, the result is utilized to derive the optimal CPU frequency. Numerical simulation results show that the proposed FCBAFL algorithm exhibits more excellent convergence compared with baseline algorithm, and outperforms other schemes in declining the energy consumption.

• 대한물리의학회지
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• 제5권3호
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• pp.405-412
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• 2010

Purpose : The purpose of this study was to assess the effects of the trunk muscle activity on bridging exercise according to the knee joint angle. Methods : Twenty-five healthy adults volunteered to participate in this study. Subjects were required to complete following four bridging exercises; knee joint flexion $120^{\circ}$, $90^{\circ}$, $60^{\circ}$, $45^{\circ}$. Surface electromyography from selected trunk muscles was normalized to maximum voluntary isometric contraction. Muscle activity was measured by QEMG-4 system(LXM 3204, Laxtha Korea). A repeated measures of one-way ANOVA with post-hoc Bonferroni's correction was used to determine the influence of bridging exercise on muscle activity for each muscle and descriptive statistics was used to determine local/global muscle ratio. Results : The internal oblique of bridging exercises $120^{\circ}$, $90^{\circ}$ showed significantly(p<.05). The erctor spinae of all bridging exercises showed significant excepted between $60^{\circ}$ and $45^{\circ}$(p<.05). Median of internal oblique/rectus abdominis ratio of $120^{\circ}$ was 4.41, $90^{\circ}$ was 3.94, $60^{\circ}$ was 3.58, $45^{\circ}$ was 3.39. Median of internal oblique/external oblique ratio of $120^{\circ}$ was 2.66, $90^{\circ}$ was 2.43, $60^{\circ}$ was 2.87, $45^{\circ}$ was 2.64. Conclusion : Angular motion decreasing with knee joint flexion made erector spinae activation increase. on the other hand, as decreasing abdomen muscle activation, the more performing motor learning is required for abdomen muscle strength and co-contraction for the trunk stabilization.

• 한국해양공학회지
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• 제18권6호
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• pp.79-83
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• 2004

The curved blocks which compose the bow and stem of a ship contain many skewed joints that are inclined horizontally and vertically. Most of these joints have a large fitness error and are continuously changing their form and are not easily accessible. The welding position and parameter values should be appropriately set in correspondence to the shape and the inclination of the joints. The welding parameters such as current, voltage, travel speed, and melting rate, are related to each other and their values must be in a specific limited range for the sound welding. These correlations and the ranges are dependent up on the kind and size of wire, shielding gas, joint shape and fitness. To determine these relationships, extensive welding experiments were performed. The experimental data were processed using several information processing technologies. The regression method was used to determine the relationship between current voltage, and deposition rate. When a joint is inclined, the weld bead should be confined to a the limited size, inorder to avoid undercut as well as overlap due to flowing down of molten metal by gravity. The dependency of the limited weld size which is defined as the critical deposited area on various factors such as the horizontally and vertically inclined angle of the joint, skewed angle of the joint, up or down welding direction and weaving was investigated through a number of welding experiments. On the basis of this result, an ANN system was developed to estimate the critical deposited area. The ANN system consists of a 4 layer structure and uses an error back propagation learning algorithm. The estimated values of the ANN were validated using experimental values.

• 재활복지공학회논문지
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• 제10권4호
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• pp.259-265
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• 2016

본 논문에서는 폐질환 조기 검출을 위하여 Broncho vascular, Emphysema, Ground Glass Reticular, Ground Glass, Honeycomb, Normal의 6가지 폐조직에 대한 새로운 분류기법을 제안하였다. 단순 베이즈 분류기와 아다부스트 학습 기법을 도입하여 459개의 결합 히스토그램 특징인자로부터 유효한 특징인자를 선별함으로써 폐조직을 분류하였다. 다중 해상도 해석, 체적 LBP 및 CT 휘도를 기반으로 하는 결합 히스토그램 특징인자는 정확도, 민감도, 특이도 결과에서 기존의 3D AMFM보다 우수한 결과를 보였다. 제안한 특징인자와 3D AMFM 특징인자의 정확도는 각각 90.1%과 85.3%로서 제안한 특징인자의 우수한 분류 성능을 확인하였다.