• Smart Structures and Systems
• /
• v.14 no.6
• /
• pp.1269-1289
• /
• 2014

With the sub-stepping technique, the numerical analysis in real-time dynamic hybrid testing is split into the response analysis and signal generation tasks. Two target computers that operate in real-time may be assigned to implement these two tasks, respectively, for fully extending the simulation scale of the numerical substructure. In this case, the integration time-step of solving the dynamic response of the numerical substructure can be dozens of times bigger than the sampling time-step of the controller. The time delay between the real and desired feedback forces becomes more striking, which challenges the well-developed delay compensation methods in real-time dynamic hybrid testing. This paper focuses on displacement prediction and force correction for delay compensation in the real-time dynamic hybrid testing with a large integration time-step. A new displacement prediction scheme is proposed based on recently-developed explicit integration algorithms and compared with several commonly-used prediction procedures. The evaluation of its prediction accuracy is carried out theoretically, numerically and experimentally. Results indicate that the accuracy and effectiveness of the proposed prediction method are of significance.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.8 no.4 s.23
• /
• pp.24-31
• /
• 2005

This paper presents an implementation of a real-time multi-sensor data fusion algorithm for Flight Test Computer. The sensor data consist of positional information of the target from a radar, a GPS receiver and an INS. The data fusion algorithm is designed by the 21st order distributed Kalman Filter which is based on the PVA model with sensor bias states. A fault detection and correction logics are included in the algorithm for bad measurements and sensor faults. The statistical parameters for the states are obtained from Monte Carlo simulations and covariance analysis using test tracking data. The designed filter is verified by using real data both in post processing and real-time processing.

• Journal of Biosystems Engineering
• /
• v.27 no.2
• /
• pp.143-150
• /
• 2002

Several researches for site-specific weed control have tried to increase accuracy of weed detection with machine vision technique. However, there is a problem which needs substantial time to perform site-specific spraying. Therefore, new technology for real-time precision spraying system is needed. This research was executed to develope the new technology to estimate weed density and size in real time, and to conduct a real-time site-specific spraying. It would effectively reduce herbicide amounts applied for a crop field. The real-time precision spraying system consisted of a Differential Global Positioning System (DGPS) with an error of 2 cm, a machine vision system, a geomagnetic sensor for correction of view point of CCD camera and an automatic sprayer with separately controlled nozzle. The weed density was calculated with comparison between position information and a pre-designed electronic map. The position information was obtained in real time using the DGPS and the machine vision. The electronic map contained a position database of crops automatically constructed when seeding. The developed system was tested on an experimental field of Seoul National University. Success rate of the spraying was about 61%.

• Journal of Positioning, Navigation, and Timing
• /
• v.9 no.3
• /
• pp.237-248
• /
• 2020

GNSS has been evolving dramatically in recent years. There are currently 6 GNSS (4 GNSS, AND 2 RNSS) constellations, which are GPS (USA), GLONASS (Russia), BeiDou (China), Galileo (EU), QZSS (Japan), and IRNSS (India). The Number of navigation satellites is expected to be over 150 by 2020. As the number of both constellations and satellites used for the improvement of positioning performance, high accuracy, and robustness of precise positioning is more promising. However, a large amount of the correction messages is required to support the augmentation system for the available satellites of all the constellations. Since bandwidth for the correction messages is generally limited, sending or scheduling the correction messages might be a critical issue in the near future. In this study, we analyze the relationship between the size of the bandwidth and Real-Time Kinematics (RTK) performance. Multiple Signal Messages (MSM), the only Radio Technical Commission for Maritimes (RTCM) message that supports multi-constellation GNSS, has been used for this assessment. Instead of the conventional method that broadcasts all the messages at the same time, we assign the MSM broadcasting interval for each constellation in 5 seconds. An open sky static and dynamic test for this study was conducted on the roof of Sejong University. Our results show that the RTK fixed position accuracy is not affected by the 5-second interval corrections, but the ambiguity fixing rate is degraded for poor DOP cases when RTK correction are transmitted intermittently.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.4 no.1
• /
• pp.22-26
• /
• 2003

Overlap Errors and side-lobes have been simultaneously solved by the rule-based correction using the rules extracted from test patterns. Lithography process parameters affecting attPSM lithography process have been determined by the fitting method to the real process data. The correction using scattering bars has been compared to the Cr shield method. The optimal insertion rule of the scattering bal's has made it possible to suppress the side-lobes and to enhance DOF at the same time. Therefore, in this paper, the solution to both side-lobe and overlap Error has been proposed using rule-based confection. Compared to the existing Cr shield method, the proposed rule-based correction with scattering bars can reduce the process complexity and time for mask production.

• Journal of Advanced Navigation Technology
• /
• v.22 no.5
• /
• pp.375-383
• /
• 2018

In order to apply the Network RTK (real time kinematics) technology, which has been used for positioning of stationary points, to the navigation of vehicles, its infrastructure should provide correction data with a quality indicator that can show the expected accuracy in real time. In this paper, we analyzed various indicator generation algorithms such as I95 (ionospheric index 95) / G95 (geodetic index 95), SBI (semivariance based index) and RIU (residual interpolation uncertainty). We also applied them to the raw observables from the reference stations of National Geographic Information Institute and VRS (virtual reference station) users, and then examined its feasibility to be used as a real-time performance index of the Network RTK rover. 24 hour data analysis shows that the RIU index, which can represent the non-linearty of the correction, has the strongest correlation with the Network RTK rover accuracy. Therefore, RIU index is expected to be used as a real-time performance index of the Network RTK rover.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.51 no.1
• /
• pp.46-54
• /
• 2002

Plasma Display Panel (PDP) is required to be both the determination of white point of each gray level and the inverse gamma correction since no-balanced RGB cell and linear property of PDP, respectively. However, these two methods cause degradation of grey level representation and undesirable false contour in the dark areas on PDP. In this paper, we implemented real time image processor of the proposed error diffusion algorithm and unsharp masking operation to protect the blurring image caused by the error diffusion. Experimental results showed drastic improvements of gray level representation and reduction of undesirable false contour.

• ETRI Journal
• /
• v.34 no.1
• /
• pp.138-141
• /
• 2012

This letter proposes a real-time digital image stabilization system for cell phone cameras without the need for frame memory. The system post-processes an image captured with a safe shutter speed using an adaptive denoising filter and a global color correction algorithm. This system can transfer the normal brightness of an image previewed under long exposure to the captured image making it bright and crisp with low noise. It is even possible to take photos in low-light conditions. By not needing frame memory, the approach is feasible for integration into the size-constrained image sensors of cell phone cameras.

• International journal of advanced smart convergence
• /
• v.9 no.4
• /
• pp.139-148
• /
• 2020

Walking is one of the most natural and repetitive actions we do in our daily lives. However, many modern people have problems with shoulders, back and spine due to incorrect walking habits. Therefore, it is becoming important to diagnose and correct wrong walking habits, for example, in-toeing, out-toeing, etc. early, which can be a precursor to various diseases. In this study, we developed the system to diagnose and prevent incorrect gait by grasping and analyzing the angle and muscle activity of the foot according to the typical wrong gait type through MPU 6050 acceleration sensor and the surface EMG sensor. Through a smartphone, numerical and visualization screens based on walking can be used to represent the angle of the feet, real-time EMG values, and even the number of steps. The correction effect was enhanced by improving the cognitive ability through a system that allows individuals to easily diagnose gait through smart devices and improve them according to their own problems.

• International conference on construction engineering and project management
• /
• 2017.10a
• /
• pp.210-213
• /
• 2017

The construction industry has witnessed an exponential growth of drones used in the field over the past few years. Likewise, the field of maintenance has paid increasing attention to using drones with a view to improving the efficiency of condition checks in high-rise buildings and major space. Although operators manipulate drones to inspect buildings at present, drones are expected to autonomously move around without operators in a few years. Also, for indoor maintenance, it is important for drones to find accurate locations, which is implemented by real-time locating systems(RTLS). Yet, the accuracy of RTLS varies across the types of systems and indoor settings, which warrants a locating system suitable for indoor space and a location correction system designed to improve the accuracy. Hence, the current study investigated the accuracy of real-time locating systems(RTLS) for the maintenance of indoor space of buildings with drones and delved into the methods of correcting the location information to improve the accuracy of RTLS.