• 한국과학교육학회지
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• 제39권1호
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• pp.89-99
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• 2019

이 연구는 중학교 '진화' 단원을 디지털 교재로 개발하여 학생들의 진화 개념 형성과 학습에 대한 흥미에 효과가 있는지 알아보고자 하였다. 오랜 시간에 의한 생물의 변화를 설명하는 생물 진화에 대한 설명은, 많은 내용을 다양하게 제공할 수 있고, 영상을 제작하고 편집할 수 있으며, 어려운 개념을 재미있게 제공할 수 있는 디지털 교과서가 서책형 교과서를 통해 이루어질 때 효과적일 수 있다. 연구를 위해 먼저 5E 순환학습 모형을 기반으로 전자책 저작 도구인 iBooks Author를 활용하여, 4차시로 구성된 진화수업을 만들었다. 개발한 디지털 교재의 효과 검증을 위해 서책형 수업과 디지털 교과서를 활용한 수업을 비교했다. 서책형 교재를 통한 수업과 디지털 교재를 활용한 수업 모두 진화 개념 형성에 유의미한 효과를 보였으나 생명 과학 흥미도와 진화 흥미도는 디지털 교재 수업 집단에서만 유의미하게 증가하였다. 또한 학생을 유형별로 나누어 디지털 교과서 효과를 확인한 결과 디지털 리터러시에 따라 스마트 기기에 친숙한 그룹이 수업에 더 적극적이었고 흥미가 높았다. 개발된 디지털 교재의 만족도 역시 디지털 리터러시가 높은 그룹에서 긍정적인 점수를 나타냈다. 이 연구 결과는 진화 영역 디지털 교재 개발은 어려운 진화 개념을 쉽고 재미있게 접근할 수 있는 수업 도구가 될 수 있음을 알려준다.

• 전기학회논문지P
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• 제58권4호
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• pp.397-403
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• 2009

In this paper, an exciter current control of a synchronous generator for ships using a compound type digital automatic voltage regulator (DVAR) in order to provide a constant output voltage of the generator is presented. The compound type DAVR is composed of a controller part to adjust output voltage and an power source unit to supply power to the exciter. The controller part, which generates the PWM switching pattern via the PI controller, drives a power MOSFET for bypass to limit the SG's exciter current. The power source unit part is parallel connected to an output terminal of the generator through a reactor and a power CT. The residual magnetic flux of SG provides exciter current to the exciter through the reactor during the initial running or no load state and load current supplies field current to the exciter through the power CT during loading state. This paper confirmed an experiment to verify the validity of compound type DAVR system for controlling output voltage of synchronous generator.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권2호
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• pp.486-503
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• 2023

Logs play an important role in mastering the health of the system, experienced operation and maintenance engineer can judge which part of the system has a problem by checking the logs. In recent years, many system architectures have changed from single application to distributed application, which leads to a very huge number of logs in the system and manually check the logs to find system errors impractically. To solve the above problems, we propose a method based on Message Middleware and ATT-GRU (Attention Gate Recurrent Unit) to detect the logs anomaly of distributed systems. The works of this paper mainly include two aspects: (1) We design a high-performance distributed logs collection architecture to complete the logs collection of the distributed system. (2)We improve the existing GRU by introducing the attention mechanism to weight the key parts of the logs sequence, which can improve the training efficiency and recognition accuracy of the model to a certain extent. The results of experiments show that our method has better superiority and reliability.

• 디지털산업정보학회논문지
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• 제18권1호
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• pp.11-24
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• 2022

Open Radio Access Network (O-RAN) standard has been proposed to separate the baseband signal processing unit from the Radio Frequency (RF) unit at base station system mainly for reducing the cost of base station systems through open-source interfaces between the two units. To satisfy the performance metrics in various scenarios, several fronthaul functional split options were presented by O-RAN. Amongst these options, the split option 7-2x is widely adopted in practical applications due to its excellent trade-off between the required bandwidth and RU overhead. In this paper, we present a hardware implementation of a base station system that is compliant with the Category B of O-RAN split option 7-2x. It consists of O-DU and O-RU implemented with a commercial off-the-shelf Digital Signal Processor and RF transceiver, respectively. The performance of the proposed base station system is evaluated in terms of Bit Error Rate and received signal power as well as the required fronthaul bandwidth. Through various experimental tests, we have observed that the proposed system reduces the fronthaul bandwidth nearly by 89.7% compared to the conventional system that dose not employ the O-RAN standard.

• 대한임베디드공학회논문지
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• 제19권4호
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• pp.203-210
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• 2024

The automotive industry is transitioning from traditional internal combustion engines to systems powered by motors, batteries, and various electronic control units. Central to this shift is the micro-controller unit, which processes data from various sensors for real-time environmental awareness and control. This paper explores using non-contact magnetic sensors for sensing vehicle inclination as part of a digital twin implementation. Unlike optical or contact sensors, non-contact magnetic sensors offer robust performance in challenging environments, providing consistent and reliable data under varying conditions. To optimize real-time data processing, we propose a double buffer structure to enhance digital signal processing performance in embedded systems. Experiments using a custom sensor-integrated board demonstrate that the double buffer structure with direct memory access-enabled serial peripheral interface significantly reduces data processing time and improves noise reduction filtering. Our results show that the proposed system can greatly enhance the reliability and accuracy of sensor data, crucial for real-time vehicle control systems. In particular, by using the double buffer structure proposed in this paper, it was possible to secure 8.27 times more data compared to raw data, despite performing additional filtering. The techniques outlined have potential applications in various fields, offering enhanced monitoring and optimization capabilities, thus paving the way for more advanced and efficient vehicle control technologies.

• IEIE Transactions on Smart Processing and Computing
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• 제5권1호
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• pp.29-34
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• 2016

A controller area network (CAN) controller is an integral part of an electronic control unit, particularly in an advanced driver assistance system application, and its characteristics should always be advantageous in all aspects of functionality especially in real time application. The cost should be low, while maintaining the functionality and reliability of the technology. However, a CAN protocol implementing serial operation results in slow throughput, especially in a cyclical redundancy checking (CRC) unit. In this paper, digital signal processing (DSP) algorithms are implemented, namely pipelining, unfolding, and retiming the CAN controller in the CRC unit, particularly for the encoder and decoder sections. It must attain a feasible iteration bound, a critical path that is appropriate for a CAN system, and must obtain a superior design of a high-speed parallel circuit for the CRC unit in order to have a faster transmission rate. The source code for the encoder and decoder was formulated in the Verilog hardware description language.

• Smart Structures and Systems
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• 제3권1호
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• pp.69-88
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• 2007

In this study, Field-Programmable Gate Arrays (FPGAs) are investigated as a practical solution to the challenge of designing an optimal platform for implementing algorithms in a wireless sensing unit for structuralhealth monitoring. Inherent advantages, such as tremendous processing power, coupled with reconfigurable and flexible architecture render FPGAs a prime candidate for the processing core in an optimal wireless sensor unit, especially when handling Digital Signal Processing (DSP) and system identification algorithms. This paper presents an effort to create a proof-of-concept unit, wherein an off-the-shelf FPGA development board, available at a price comparable to a microprocessor development board, was adopted. Data processing functions, including windowing, Fast Fourier Transform (FFT), and peak detection, were implemented in the FPGA using a Matlab Simulink-based high-level abstraction tool rather than hardware descriptive language. Simulations and laboratory tests were carried out to validate the design.

• 전기학회논문지
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• 제64권2호
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• pp.310-314
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• 2015

To improve the optical performance of the backlight unit with light guide plate(LGP), we investigated the effects of LGP patterns on the brightness and viewing angles properties of the backlight unit. We designed several patterns of LGP and calculated their optical properties by the optical simulation. The results reveal that the highest brightness and wide viewing angle was achieved with the extended-closed-polygon diffusion pattern and upper triangle prism pattern of the LGP.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅲ
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• pp.1403-1406
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• 2003

This paper presents a user preference description for graphics contents that is developed in the process of the MPEG-21 DIA(Digital Item Adaptation) standard. The description scheme in this paper is proposed by the authors and adopted in the current AM (Adaptation Model) document of the MPEG-21 DIA. The goal of MPEG-21 standard is providing a multimedia framework that Provides augmented and transparent use of digital contents across various networks and terminals fur the life cycle of digital contents. DI (Digital Item) is a standardized basic unit of digital contents for transaction in the scope of MPEG-21. DIA contains both media resources and metadata including rights information.

• 한국디지털건축인테리어학회논문집
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• 제5권2호
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• pp.9-14
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• 2005

The analysis system has been needed to pre-evaluate and analyze the right for sunlight and the right for view in a residential environment since the urban high density and high rise residentinal building types have been prevailing these days. The purpose of this study is to propose an digital analysis method to evaluate sunlight and view conditions in a residential environment to improve the system performance in the sense of speed and accuracy. The digital analysis method using the object-oriented 3D CAD system and parametric library is studied and applied in the system and the various outputs of the analysis system makes possible to modify the design with the speed and accuracy as a result of the analysis. The study includes the evaluation for a daylight and view condition of each unit, and the interruption degree to a vicinity environment in terms of sunlight and view conditions comparing before and after construction.