• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.121.4-121
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• 2001

We propose an off-line methodology for detecting a faulty backup roll that generates eccentricity components, under the condition that the feeding velocity, equivalently the angular velocity of roll, is not constant. From a newly devised speed angle conversion algorithm, we transform all process data into those of a virtual process under a constant feeding speed. This indirectly way, we can apply a spectral analysis to the original process. In addition, we develop an online detection method of roll eccentricity based on newly designed PLG sensor. This PLG sensor is robust because of applying magnetic proximity sensnors and non-contact measurement method.

• Journal of Information Processing Systems
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• v.7 no.1
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• pp.93-102
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• 2011

In deeply scaled CMOS technologies, two major non-ideal factors are threatening the survival of the CMOS; i) PVT (process, voltage, and temperature) variations and ii) leakage power consumption. In this paper, we propose a novel post-silicon tuning methodology to scale optimum voltage and frequency "dynamically". The proposed design technique will use our PVT sensor circuits to monitor the variations and based on the monitored variation data, voltage and frequency will be compensated "automatically". During the compensation process, supply voltage is dynamically adjusted to guarantee the minimum total power consumption without violating the frequency requirement. The simulation results show that the proposed technique can reduce the total power by 85% and the static power by 53% on average for the selected ISCAS'85 benchmark circuits with 45 nm CMOS technology compared to the results of the traditional PVT compensation method.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.468-473
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• 2017

This paper presents an in-process measurement system for shaft radius measurement during grinding process. This system does not require to stop the grinding process, which can enhance productivity and quality. In order to measure the radius, the system employs an eddy current sensor that can measure without any contact with the shaft. This type of sensor is very appropriate because it is insensitive to interference such as cutting fluid, coolant, contact pressure, and wear. For data analysis, the measurement system is modeled as a linearized discrete form where the states with noise are estimated by an extended Kalman filter. This system has been validated through simulations and experiments.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.417-422
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• 2015

A service size of the IoT environment is determined by the number of sensors. The number of sensors increase means increases the amount of data generated by the IoT environment. There are studies to reliably operate a network for research and operational dynamic buffer for data when network congestion control congestion in the network environment. There are also studies of the stream data that has been processed in the connectionless network environment. In this study, we propose a sensor gateway for processing big data of the IoT environment. For this, review the RESTful for designing a sensor middleware, and apply the double-buffer algorithm to process the stream data efficiently. Finally, it generates a big data traffic using the MJpeg stream that is based on the HTTP protocol over TCP to evaluate the proposed system, with open source media player VLC using the image received and compare the throughput performance.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.1
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• pp.87-95
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• 2018

The high-precision magnetic levitation transport system is a transport device applying the principle of magnetic levitation. So it is preferable for manufactory process of semiconductor and display industries. In this system, the gap sensors are arranged discontinuously and turned on or off when the tray moves in the running direction. Therefore, precise gap data is important for precise control of the carrier. However, a slight error occurs in the process of installing the gap sensor. So, in this paper, we introduce the high-precision magnetic levitation transport system for OLED evaporation process. Also, we propose a strategy for stable flight control and an offset algorithm for tracking installation errors transport system. The performances of the proposed algorithm are validated through simulation.

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.87-92
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• 2007

Recently, developments of process monitoring system in order to detect and diagnose process abnormalities has got the spotlight in process systems engineering. Normal data obtained from processes provide available information of process characteristics to be used for modeling, monitoring, and control. Since modern chemical and environmental processes have high dimensionality, strong correlation, severe dynamics and nonlinearity, it is not easy to analyze a process through model-based approach. To overcome limitations of model-based approach, lots of system engineers and academic researchers have focused on statistical approach combined with multivariable analysis such as principal component analysis (PCA), partial least squares (PLS), and so on. Several multivariate analysis methods have been modified to apply it to a chemical process with specific characteristics such as dynamics, nonlinearity, and so on.This paper discusses about missing value estimation and sensor fault identification based on process variable reconstruction using dynamic PCA and canonical variate analysis.

• Journal of Korea Society of Digital Industry and Information Management
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• v.4 no.2
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• pp.1-12
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• 2008

Home network is a technology that provides possibilities of monitoring/controling/mutilating-recognition between optional home network machines in residences. Currently, home network or other networks like entertainment, residential electronic networks are jumbled together with heterogeneous networks in a rampaging condition. In a reality of high expectation for home networks system like the mutual application for various machines, we are required to have the unification technology for conveniences to satisfy expectations. This thesis reflects how to develop Java applications or mutual products based on convenient interfaces actually that process various sensors which create real time data stream in Java platform through Java based sensor data-stream processing embedded middleware design and realization in real time.

• IEMEK Journal of Embedded Systems and Applications
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• v.15 no.6
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• pp.269-279
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• 2020

This paper presents the design and implementation of embedded systems and autonomous path generation for autonomous speed sprayer. Autonomous Orchard Systems can be divided into embedded controller and path generation module. Embedded controller receives analog sensor data, on/off switch data and control linear actuator, break, clutch and steering module. In path generation part, we get 3D cloud point using Velodyne VLP16 LIDAR sensor and process the point cloud to generate maps, do localization, generate driving path. Then, it finally generates velocity and rotation angle in real time, and sends the data to embedded controller. Embedded controller controls steering wheel based on the received data. The developed autonomous speed sprayer is verified in test-bed with apple tree-shaped artworks.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.128-130
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• 2021

Smart cities collect data from thousands of IoT-based sensor devices for intelligent application-based services. Centralized cloud servers support application tasks with higher computation resources but introduce network latency. Fog layer-based data centers bring data processing at the edge, but fewer available computation resources and poor task allocation strategy prevent real-time data analysis. In this paper, tasks generated from devices are distributed as high resource and low resource intensity tasks. The novelty of this research lies in deploying a virtual node assigned to each cluster of IoT sensor machines serving a joint application. The node allocates tasks based on the task intensity to either cloud-computing or fog computing resources. The proposed Task Allocation Strategy provides seamless allocation of jobs based on process requirements.

• Journal of the Korea Society for Simulation
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• v.18 no.3
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• pp.83-90
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• 2009

Since wireless sensor networks are deployed in open environments, an attacker can physically capture some sensor nodes. Using information of compromised nodes, an attacker can launch false data injection attacks that report nonexistent events. False data can cause false alarms and draining the limited energy resources of the forwarding nodes. In order to detect and discard such false data during the forwarding process, various security solutions have been proposed. But since they are prevention-based solutions that involve additional operations, they would be energy-inefficient if the corresponding attacks are not launched. In this paper, we propose a detection method that can detect false data injection attacks without extra overheads. The proposed method is designed based on the signature of false data injection attacks that has been derived through simulation. The proposed method detects the attacks based on the number of reporting nodes, the correctness of the reports, and the variation in the number of the nodes for each event. We show the proposed method can detect a large portion of attacks through simulation.