• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.4 no.3
• /
• pp.595-602
• /
• 2000

This paper is aimed at developing an location tracking system of mobile station based on currently available mobile communication network or mobile Phone and PCS(Personal Communication System). When the location tracking of mobile stations is in services, Emergency-119, all of crime investigation, effective urban traffic management and the safety protection of Alzheimer＇s patients can be available. In order to track the location of the mobile and base station, assumption in this paper is to use the statistic characteristics of LOS when modeling the standard noise in case that radio path is LNOS environment. The standard variation of the standard noise is $\pm150$. First, location is estimated by the positioning algorithms of TOA and TDOA and compared each other. Second, after canceling the standard noise by Kalman filter, location is estimated by the above two positioning algorithms. Finally, the location by the Kalman filter and two positioning algorithms is estimated by smoothing method. As a result, 2 dimensional average location error is imvoved by 51.2m in TOA and 34.8m in TDOA when Kalman filer and two positioning algorithms are used, compared with the two positioning algorithm used. And there is 3 more meter improvement after smoothing than Kalman filer and two positioning algorithms used.

• Journal of Biosystems Engineering
• /
• v.31 no.6 s.119
• /
• pp.489-499
• /
• 2006

Since the application of chemicals in confined spaces under the canopy of an orchard is hazardous work, it is needed to develop an autonomous guidance system for an orchard sprayer. The autonomous guidance system developed in this research could steer the vehicle by tracking an overhead guidance rail, which was installed on an existing frame structure. The autonomous guidance system consisted of an 80196 kc microprocessor, an inclinometer, two interface circuits of actuators for steering and ground speed control, and a fuzzy control algorithm. In addition, overhead guidance rails for both straight and curved paths were devised, and a trolley was designed to move smoothly along the overhead guidance rails. Evaluation tests showed that the experimental vehicle could travel along the desired path at a ground speed of 30 $\sim$ 50 cm/s with a RMS error of 5 cm and maximum deviation of less than 12 cm. Even when the vehicle started with an initial offset or a deflected heading angle, it could move quickly to track the desired path after traveling 2 $\sim$ 3 m. The vehicle could also complete turns with a curvature of 1 m. However, at a ground speed of 50 cm/s, the vehicle tended to over-steer, resulting in a zigzag motion along the straight path, and tended to turn outward from the projected line of the guidance rail.

• The Korean Journal of Physiology and Pharmacology
• /
• v.22 no.6
• /
• pp.705-712
• /
• 2018

The tube formation assay is a widely used in vitro experiment model to evaluate angiogenic properties by measuring the formation of tubular structures from vascular endothelial cells (ECs). In vitro experimental results are crucial when considered the advisability of moving forward to in vivo studies. Thus, the additional attentions to the in vitro assay is necessary to improve the quality of the pre-clinical data, leading to better decision-making for successful drug discovery. In this study, we improved the tube formation assay system in three aspects. First, we used human endothelial colony forming cells (ECFCs), which are endothelial precursors that have a robust proliferative capacity and more defined angiogenic characteristics compared to mature ECs. Second, we utilized a real-time cell recorder to track the progression of tube formation for 48 hours. Third, to minimize analysis error due to the limited observation area, we used image-stitching software to increase the microscope field of view to a $2{\times}2$ stitched area from the $4{\times}$ object lens. Our advanced tube formation assay system successfully demonstrated the time-dependent dynamic progression of tube formation in the presence and absence of VEGF and FGF-2. Vatalanib, VEGF inhibitor, was tested by our assay system. Of note, $IC_{50}$ values of vatalanib was different at each observation time point. Collectively, these results indicate that our advanced tube formation assay system replicates the dynamic progression of tube formation in response to angiogenic modulators. Therefore, this new system provides a sensitive and versatile assay model for evaluating pro- or anti-angiogenic drugs.

• Korean Chemical Engineering Research
• /
• v.58 no.3
• /
• pp.390-395
• /
• 2020

For some processes with saturations, economical operating points are on the saturation edges. Traditional feedback controllers cannot be used to regulate such processes on the saturation edges because there are abrupt dynamics changes and no feedback information at saturations. Optimization-based methods such as the model predictive control can treat this control problem without difficulty when the saturation levels and dynamics are known and not varying. Otherwise, an adaptation scheme to track the saturation levels and dynamics should be included. Here, for very simple methods to treat this control problem, two control methods based on the recent slope seeking method and the relay feedback method are proposed. Their performances are evaluated with simulations applying them to a second order liquid level system with saturation. Simulations show that these proposed control methods can find and maintain operating point of the saturation edge under 5% relative error.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.2B
• /
• pp.287-295
• /
• 2010

RTLS used to track the location of object or person in real time. However, if there are a lot of tags and readers, the conventional single RTLS server may fail to estimate location of tags. And if the server cannot receive the tags signal due to pass-loss or NLOS from more than three readers, the server fail to estimate location of tags. In this paper, we propose a special reader which embeds RTLS location engine for distributed RTLS. And by using multi-directional antenna, alleviating multi-path effect and allowing estimate tag's location only using two readers. We also implement the system, we can reduce server packet 16times and get the all results of location estimate in single second. We achieved the location error within 1m.

• Proceedings of the KSRS Conference
• /
• v.1
• /
• pp.150-152
• /
• 2006

The DISCOVER Project (${\underline{D}}istributed$ ${\underline{I}}nformation$ ${\underline{S}}ervices$ for ${\underline{C}}limate$ and ${\underline{O}}cean$ products and ${\underline{V}}isualizations$ for ${\underline{E}}arth$ ${\underline{R}}esearch$) is a NASA funded Earth Science REASoN project that strives to provide highly accurate, carefully calibrated, long-term climate data records and near-real-time ocean products suitable for the most demanding Earth research applications via easy-to-use display and data access tools. A key element of DISCOVER is the merging of data from the multiple sensors on multiple platforms into geophysical data sets consistent in both time and space. The project is a follow-on to the SSM/I Pathfinder and Passive Microwave ESIP projects which pioneered the simultaneous retrieval of sea surface temperature, surface wind speed, columnar water vapor, cloud liquid water content, and rain rate from SSM/I and TMI observations. The ocean products available through DISCOVER are derived from multi-sensor observations combined into daily products and a consistent multi-decadal climate time series. The DISCOVER team has a strong track record in identifying and removing unexpected sources of systematic error in radiometric measurements, including misspecification of SSM/I pointing geometry, the slightly emissive TMI antenna, and problems with the hot calibration source on AMSR-E. This in-depth experience with inter-calibration is absolutely essential for achieving our objective of merging multi-sensor observations into consistent data sets. Extreme care in satellite inter-calibration and commonality of geophysical algorithms is applied to all sensors. This presentation will introduce the DISCOVER products currently available from the web site, http://www.discover-earth.org and provide examples of the scientific application of both the diurnally corrected optimally interpolated global sea surface temperature product and the 4x-daily global microwave water vapor product.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.3
• /
• pp.228-235
• /
• 2010

This paper deals with an autonomous flight controller design problem for a tilt-rotor aircraft in rotary-wing mode. The inner-loop algorithm is designed using the output-based approximate feedback linearization. The model error originated from the feedback linearization is cancelled within allowable tolerance by using single-hidden-layer neural network. According to Lyapunov direct stability theory, the adaptive update law is derived to run the neural network on-line, which is based on the linear observer dynamics. Moreover, the outer-loop algorithm is designed to track the trajectory generated from way-point guidance. Especially, heading and flight-path angle line-of-sight guidance are applied to the outer-loop to improve accuracy of the landing tracking performance. The 6-DOF nonlinear simulation shows that the overall performance of the flight control algorithm is satisfactory even though the collective input response shows instantaneous actuator saturation for a short time due to the lack of the neural network and the saturation protection logic in that loop.

• Convergence Security Journal
• /
• v.7 no.1
• /
• pp.29-34
• /
• 2007

Recently, the distribution and using of the digital multimedia contents are easy by developing the internet application program and related technology. However, the digital signal is easily duplicated and the duplicates have the same quality compare with original digital signal. To solve this problem, there is the multimedia fingerprint which is studied for the protection of copyright. Fingerprinting scheme is a technique which supports copyright protection to track redistributers of electronic information using cryptographic techniques. Only regular user can know the inserted fingerprint data in fingerprinting schemes differ from a symmetric/asymmetric scheme and the scheme guarantee an anonymous before re-contributed data. In this paper, we present a new scheme which is the detection of colluded multimedia fingerprint by neural network. This proposed scheme is consists of the anti-collusion code generation and the neural network for the error correction.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2000.05a
• /
• pp.167-172
• /
• 2000

This paper is aimed at developing an location tracking for mobile station employing currently available mobile communication network of cellular phone and PCS(Personal Communication System). When the location tracking of mobile stations is in services, the services such as Emergency-119, crime investigation, effective urban traffic management or the safety protection of Alzheimer's patients, ran be available. This paper is to track the mobile station in communication network in NLOS environment. To achieve reduction of the standard noise, Kalman filter is used. In terms of the distance, positions are located by using TOA and TDOA methods in the environment that removes NLOS bias in the measured data. And then smoothing method is used. to achieve reduction of the position error values

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.6
• /
• pp.290-297
• /
• 2014

The synchronization of OFDM receiver is consisted of symbol timing offset(STO) estimation in time domain and carrier frequency offset(CFO) estimation in frequency domain. This paper proposes new algorithm for correcting the integer CFO after we have done correcting the STO and partial CFO. ICFO must be corrected, since the ICFO lead to degrade bit error rate(BER) of demodulation performance. The PN sequence has information which is subcarrier order since the modified PN sequence, length is same subcarrier, is used in this paper and is modulated each subcarrier by each chip. Thus the receiver track phase of PN sequence after FFTin order to find the subcarrier frequency offset. The proposed algorithm is faster and more simple than convenient methode as measuring carrier energy.