• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.2
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• pp.61-66
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• 2014

Temporal disappearance of weather phenomena effect is frequently observed in flight simulator when large volume of terrain data are processed. This problem was solved by employing culling scheme at static ratio in the existing scheme. However, since this approach causes the irregular rendering speed according to volume of data, it is necessary to develop a new culling scheme to maintain steady rendering speed by adjusting the culling ratio dynamically. In this paper, we propose a new culling scheme to make use of distance of the visibility to determine culling ratio depending on volume of terrain data. The experimental results show that rendering speed is preserved by the proposed scheme without affecting the visuality at rendering the scene and weather phenomena effect together.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.3
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• pp.397-403
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• 2015

This paper presents a new SOC test compression scheme in Embedded Deterministic Test (EDT) compression environment. Compressed test data is brought over the TAM from the tester to the cores in SOC and decompressed in the cores. The proposed scheme allows cores tested at the same time to share some test channels. By sharing free variables in these channels across test cubes of different cores decompressed at the same time, high encoding efficiency is achieved. Moreover, no excess control data is required in this scheme. The ability to reuse excess free variables eliminates the need for high precision in matching the number of test channels with the number of care bits for every core. Experimental results obtained for some SOC designs illustrate effectiveness of the proposed test application scheme.

• IEMEK Journal of Embedded Systems and Applications
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• v.5 no.1
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• pp.39-45
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• 2010

As wireless sensor network are being deployed in a wide variety of application areas, the number of sensor nodes in a sensor filed becomes larger and larger. In the past, ISP (In-System Programming) method have been generally used for code update but the large number of sensor nodes requires a new code update method called network reprogramming. There are many challenging issues for network reprogramming since it can make an impact on the network lifetime. In this paper, a new sender selection scheme for network reprogramming protocol is proposed to decrease energy consumption for code update by minimizing overlapped area between sender nodes and reducing data contention. Simulation results show that the proposed scheme can reduce the amount of message traffic and the overall data transmission time.

• IEMEK Journal of Embedded Systems and Applications
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• v.16 no.6
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• pp.253-258
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• 2021

In this paper, we developed a hardware and software platform of the real-time data logging system to verify radar FEM (Front-end Module) and signal-processing algorithms. We developed a hardware platform based on FPGA (Field Programmable Gate Array) and DSP (Digital Signal Processor) and implemented firmware software to verify the various FEMs. Moreover, we designed PC based software platform to control radar logging parameters and save radar data. The developed platform was verified using 24 GHz multiple channel FMCW (Frequency Modulated Continuous Wave) in an environment of stationary and moving targets of chamber room.

• IEMEK Journal of Embedded Systems and Applications
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• v.14 no.2
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• pp.79-86
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• 2019

For decades, in-memory data structures have been designed for DRAM-based main memory that provides symmetric read/write performances and has no limited write endurance. However, such data structures provide sub-optimal performance for NVM as it has different characteristics to DRAM. With this motivation, we rethink a conventional red-black tree in terms of its efficacy under NVM settings. The original red-black tree constantly rebalances sub-trees so as to export fast access time over dataset, but it inevitably increases the write traffic, adversely affecting the performance for NVM with a long write latency and limited endurance. To resolve this problem, we present a variant of the red-black tree called a hierarchical balanced binary search tree. The proposed structure maintains multiple keys in a single node so as to amortize the rebalancing cost. The performance study reveals that the proposed hierarchical binary search tree effectively reduces the write traffic by effectively reaping the high capacity of NVM.

• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.3
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• pp.185-190
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• 2022

We propose a high speed data communication method for motor drive systems with fast control cycle in order to collect state variables of motor control without degrading control performance. Ethernet is chosen for communication device, and multi-core DSP architecture is exploited for communication processing load distribution. The communication program including network protocol stack and motor control program are assigned to two separate cores, and data between two cores are exchanged using interrupt-based inter-process communication mechanism, which enables to achieve a high-speed communication performance without degrading the motor control performance. The performance of developed communication method is demonstrated by real experiments using TCP, UDP and Raw Socket protocols in an experimental setup consisting of TI's TMS320F28388D motor control card and MS Windows PC.

• Proceedings of the Korean Society of Computer Information Conference
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• 2023.07a
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• pp.95-97
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• 2023

본 논문에서는 임베디드 기반의 다양한 센서를 활용한 드론의 비행기록장치 시스템 개발에 대한 새로운 아이디어를 제시한다. 이 시스템은 오픈소스 기반의 개발 보드인 라즈베리파이를 중심으로, 온도, 습도, 조도, 미세먼지 센서, 이산화탄소, 일산화탄소, 산소, 이산화질소, 아황산가스, 메탄가스, GPS, 고도 측정, IR 카메라, 카메라 모듈 센서 등 다양한 센서를 탑재하여 구성한다. 기존 드론은 주로 방역 및 방제 활동에 활용되었으나, 그 활동의 효과를 정밀하게 측정하고 분석하는 데에는 한계가 있었다. 그러나 이 논문에서 제안하는 임베디드 기반의 센서 구성은 이러한 한계를 극복할 수 있을 것으로 기대된다.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.7
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• pp.720-725
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• 2008

This paper proposes a system architecture for USN with a service robot to provide more active assisted living services for elderly persons by monitoring their mental and physical well-being with USN environments at home, hospital, or silver town. Sensors embedded in USN are used to detect preventive measures for chronic disease. Logged data are transferred to main controller of a service robot via wireless channel in which the analysis of data is performed. For the purpose of handling emergency situations, it needs real-time processing on gathering variety sensor data, routing algorithms for sensor nodes to a moving sink node and processing of logged data. This paper realized multi-hop sensor network to detect user movements with biometric data transmission and performed algorithms on Xenomai, a real-time embedded Linux. To leverage active sensing, a mobile robot is used of which task was implemented with a priority to process urgent data came from the sink-node. This software architecture is anticipated to integrate sensing, communication and computing with real-time manner. In order to verify the usefulness of a proposed system, the performance of data transferring and processing on a real-time OS with non real-time OS is also evaluated.

• IEMEK Journal of Embedded Systems and Applications
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• v.2 no.1
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• pp.31-42
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• 2007

A transform coding scheme for the transmission of audio data in ZigBee based wireless personal area networks (WPAN) is presented in this paper. Here, wavelet transform is exploited to encode the features of audio data included mainly in the low frequency region. As a result, it is confirmed that the presented scheme recovers the original audio signals much accurately while it transmits the binary data compressed as 37.5% of the entire data generated without coding scheme. Especially, the mean-squared error between the recovered and original audio data approaches $10^{-4}$ when the signal-to-noise power ratio is sufficiently high. Hence, the presented coding scheme which exploits the wavelet transform is possibly applied for high-quality audio data transmission services in a small-scale sensor network based on ZigBee. Such a result is considered to be applicable as a basic material to update the technical specifications and develop the applications of ZigBee in WPANs.

• Journal of Broadcast Engineering
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• v.2 no.1
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• pp.65-73
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• 1997

This paper propose a new triangular mesh approximation method using wavelet coefficients for large terrain data. Using spatio-freguency localization characteristics of wavelet coefficients, we determine the complexity of terrain data and approximate the data according to the complexity. This proposed algorithm is simple and requires low computational cost due to its top-down approach. Because of the similarity between the mesh approximation and data compression procedures based on wavelet transform, we combine the mesh approximation scheme with the Embedded Zerotree Wavelet (EZW) coding scheme for the effective management of large terrain data. Computer simulation results demonstrate that the proposed algorithm is very prospective for the 3-D visualization of terrain data.