• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.11
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• pp.2009-2014
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• 2007

A novel method of minimizing video quality variation is proposed for a real-time frame-layer rate control algorithm with a transmission buffer. The proposed rate control method uses a non-iterative optimization method for low computational complexity, and performs bit allocation at the frame level to minimize variation in distortion between frames. In order to reflect the buffer status, we use well-known PID control method. Computational complexity of PID control is very low, so the proposed algorithm is suitable for real-time low-complexity video encoder. Experimental results indicate that the proposed control method provides better PSNR performance than the existing rate control method.

• Journal of the Korea Society of Computer and Information
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• v.24 no.11
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• pp.1-9
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• 2019

In this paper, we propose a Small Active Command scheme which reduces the power consumption of the command bus to DRAM. To do this, we target the ACTIVE command, which consists of multiple packets, containing the row address that occupies the largest size among the addresses delivered to the DRAM. The proposed scheme identifies frequently referenced row addresses as Hot pages first, and delivers index numbers of small caches (tables) located in the memory controller and DRAM. I-ACTIVE and I-PRECHARGE commands using unused bits of existing DRAM commands are added for index number transfer and cache synchronization management. Experimental results show that the proposed method reduces the command bus power consumption by 20% and 8.1% on average in the close-page and open-page policies, respectively.

• Journal of Drive and Control
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• v.16 no.3
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• pp.67-74
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• 2019

The automotive market has recently been investing much time and costs in improving existing technologies such as ABS (Anti-lock Braking System) and TCS (Traction Control System) and developing new technologies. Additionally, various methods have been applied and developed to reduce this. Among them, the development method using the simulation has been mainly used and developed. In this paper, we have studied a method to develop SILS (Software In the Loop Simulation) for TCS which can test various environment variables under the same conditions. We modeled hardware (vehicle engine and ABS module) and software (control logic) of TCS using MATLAB/Simulink and Carsim. Simulation was performed on the climate, road surface, driving course, etc. to verify the TCS logic. By using SILS to develop TCS control logic and controller, it is possible to verify before production and reduce the development period, manpower and investment costs.

• IEMEK Journal of Embedded Systems and Applications
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• v.14 no.1
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• pp.33-41
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• 2019

We propose an embedded solution to design a high-speed and high-accuracy 16bit analog-digital signal processing interface for the control systems using various external analog signals. Choosing TMS320F28377D micro controller unit (MCU) featuring high-performance processing in the 32-bit floating point operation, low power consumption, and various I/O device supports, we design and build the proposed system that supports both 16-bit analog-digital converter (ADC) interface and high precision digital-analog converter (DAC) interface. The ADC receives voltage-level differential signals from fully differential amplifiers, and the DAC communicates with MCU through 50 MHz bandwidth high-fast serial peripheral interface (SPI). We port the boot loader and device drivers to the implemented board, and construct the firmware development environment for the application programming. The performance of the entire implemented system is demonstrated by analog-digital signal processing tests, and is verified by comparing the test results with those of existing similar systems.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.159-160
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• 2019

It would be very important to localize people at risk as soon as possible in order to minimize the damage. Generally the infrastructure should be deployed additionally for indoor positioning system. In this paper, we proposed an indoor localization system for people at risk using the existing fire alarm networks. The system detects the signal of smart devices of people in danger immediately and let the main alarm controller ring all alarms in vessel and display the position. Thus, the proposed system can make the burden much less to deploy additional network and infrastructure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5654-5668
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• 2018

Driven by security and real-time demands of Internet of Things (IoT), the timing of fog computing and edge computing have gradually come into place. Gateways bear more nearby computing, storage, analysis and as an intelligent broker of the whole computing lifecycle in between local devices and the remote cloud. In fog computing, the edge broker requires X-aware capabilities that combines software programmability, stream processing, hardware optimization and various connectivity to deal with such as security, data abstraction, network latency, service classification and workload allocation strategy. The prosperous of Field Programmable Gate Array (FPGA) pushes the possibility of gateway capabilities further landed. In this paper, we propose a software-defined gateway (SDG) scheme for fog computing paradigm termed as Fog Computing Zero-Knowledge Gateway that strengthens data protection and resilience merits designed for industrial internet of things or highly privacy concerned hybrid cloud scenarios. It is a proxy for fog nodes and able to integrate with existing commodity gateways. The contribution is that it converts Privacy-Enhancing Technologies rules into provable statements without knowing original sensitive data and guarantees privacy rules applied to the sensitive data before being propagated while preventing potential leakage threats. Some logical functions can be offloaded to any programmable micro-controller embedded to achieve higher computing efficiency.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.113-118
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• 2020

Recently, eco-friendly electric motorcycles have been considered to replace aging gasoline motorcycles to reduce the amount of suspended fine dust in air. However, existing rechargeable battery-powered electric motorcycles have been found unacceptable by users because of their many limitations, such as long charging time, short travel distance per charge, and low driving speed. To overcome the drawbacks of conventional electric motorcycles, this paper proposes an exchangeable battery-powered electric motorcycle and a new frame shape for housing the exchangeable battery. The proposed frame is similar to that of current electric motorcycles; however, the shape and position of the saddle support, battery, and controller mount section are redesigned. The safety of the presented frame is verified through static and dynamic analyses using ABAQUS. In particular, the dynamic analysis is conducted under the most extreme condition among the various operating situations, thus confirming the robustness of the proposed frame design.

• International journal of advanced smart convergence
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• v.11 no.3
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• pp.206-214
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• 2022

Automobile manufacturers in each country are spurring the development of electric vehicles that use electric energy, an eco-friendly energy, as a futuristic vehicle. Electric vehicles have the advantage of no harmful gas or environmental pollution and low noise. Unlike automobiles using existing internal combustion engines using fossil fuels, electric vehicles use the electricity of batteries to cause rotational motion of motors. In the electric vehicle driven by the motor, it is indispensable to develop a controller for controlling the motor. One of the areas where automobile manufacturers are concentrating is the development of small electric vehicles as a personal transportation means. Small electric vehicles such as electric motorcycles, one-seat electric vehicles and two-seat electric vehicles are expanding the market as a means of operating throughout the city. In the domestic road conditions with many hills, it is effective to have a separate transmission system for small electric vehicles to drive smoothly. In this study, we propose a new type of continuously variable transmission(CVT) system to ensure that small electric vehicles can be driven smoothly in hilly domestic terrain. The proposed CVT system is equipped with a basic disk and a rotational disk in the driving pulley and the driven pulley, respectively, and is applied with a sloping spline to rotate the rotational disk. To commercialize the proposed CVT system, an experimental device was developed to examine the power transmission efficiency and the configuration of the CVT system was proposed.

• Smart Structures and Systems
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• v.29 no.4
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• pp.577-588
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• 2022

Oil refineries' Fluid Catalytic Cracking Units (FCCU) when in full operation may exhibit strong fluid dynamics caused by turbulent flow in the piping system that may induce vibrations in other mechanical and structural components of the Unity. This paper reports on the experimental-theoretical-computational program performed to get the vibration properties and the dynamic response amplitudes to find out alternative solutions to attenuate the excessive vibrations that were causing fatigue fractures in components of the bottle like reactor-regenerator of an FCC unit in operation in an existing oil refinery in Brazil. Solutions to the vibration problem were sought with the aid of a 3D finite element model calibrated with the results obtained from experimental measurements. A short description of the found solutions is given and their effectiveness are shown by means of numerical results. The solutions were guided by the concepts of structural stiffening and dynamic control performed by a nonlinear pendulum controller whose mechanical design was based on parameters determined by means of a parametric study carried out with 2D and 3D mathematical models of the coupled pendulum-structure system. The effectiveness of the proposed solutions is evaluated in terms of the fatigue life of critical welded connections.

• Journal of Internet Computing and Services
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• v.22 no.6
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• pp.1-8
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• 2021

With the rapid growth of intelligent devices and communication technologies, 5G network environment has become more heterogeneous and complex in terms of service management and orchestration. 5G architecture requires supportive technologies to handle the existing challenges for improving the Quality of Service (QoS) and the Quality of Experience (QoE) performances. Among many challenges, traffic steering is one of the key elements which requires critically developing an optimal solution for smart guidance, control, and reliable system. Mobile edge computing (MEC), software-defined networking (SDN), network functions virtualization (NFV), and deep learning (DL) play essential roles to complementary develop a flexible computation and extensible flow rules management in this potential aspect. In this proposed system, an accurate flow recommendation, a centralized control, and a reliable distributed connectivity based on the inspection of packet condition are provided. With the system deployment, the packet is classified separately and recommended to request from the optimal destination with matched preferences and conditions. To evaluate the proposed scheme outperformance, a network simulator software was used to conduct and capture the end-to-end QoS performance metrics. SDN flow rules installation was experimented to illustrate the post control function corresponding to DL-based output. The intelligent steering for network communication traffic is cooperatively configured in SDN controller and NFV-orchestrator to lead a variety of beneficial factors for improving massive real-time Internet of Things (IoT) performance.