• Journal of Korea Multimedia Society
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• v.10 no.3
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• pp.303-315
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• 2007

This paper proposes a 3D structure recovery and registration method that uses four or more common points. For each frame of a given video, a partial structure is recovered using tracked points. The 3D coordinates, camera positions and camera directions are computed at once by our improved scaled orthographic factorization method. The partially recovered point sets are parts of a whole model. A registration of point sets makes the complete shape. The recovered subsets are integrated by transforming each coordinate system of the local point subset into a common basis coordinate system. The process of shape recovery and integration is performed uniformly and linearly without any nonlinear iterative process and without loss of accuracy. The execution time for the integration is significantly reduced relative to the conventional ICP method. Due to the fast recovery and registration framework, our shape recovery scheme is applicable to various interactive video applications. The processing time per frame is under 0.01 seconds in most cases and the integration error is under 0.1mm on average.

• Aerospace Engineering and Technology
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• v.11 no.2
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• pp.96-102
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• 2012

Recently, interests about frame error reduction method, using multiple PCM data which are received at several ground stations, are increasing. Simple data merge method is already applied to data processing system at Naro Space Center and have been used in the first and the second flight test analysis of KSLV-I. This paper is focused on error reduction with error correcting merge algorithm and time-delayed data correction algorithm. Result of applying the proposed algorithms to the flight test data shows 1.32% improvement in error rate, compared to simple-data-merge method. It is considered that presented algorithms could be very useful in generating various telemetry merge data.

• Korean Chemical Engineering Research
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• v.55 no.5
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• pp.652-659
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• 2017

In the present research, in order to predict activity coefficient of inorganic ions in electrolyte solution of a petroleum system, we studied 13 components in the electrolyte solution, including $H_2O$, $CO_2$ (aq), $H^+$, $Na^+$, $Ba^{2+}$, $Ca^{2+}$, $Sr^{2+}$, $Mg^{2+}$, $SO_4$, $CO_3$, $OH^-$, $Cl^-$, and $HCO_3$. To predict the activity coefficient of the components of the petroleum system (a solid/liquid equilibrium system), activity coefficient model of Extended UNIQUAC was studied, along with its adjustable parameters optimized based on a genetic algorithm. The total calculated error associated with optimizing the adjustable parameters of Extended UNIQUAC model considering the 13 components under study at three temperature levels (298.15, 323.15, and 373.15 K) using the genetic algorithm is found to be 0.07.

• ETRI Journal
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• v.46 no.2
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• pp.227-237
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• 2024

This study proposes a novel, conditionally applied neural network technique to reduce the overall peak-to-average power ratio (PAPR) of an orthogonal frequency division multiplexing (OFDM) system while maintaining an acceptable bit error rate (BER) level. The main purpose of the proposed scheme is to adjust only those subcarriers whose peaks exceed a given threshold. In this respect, the developed C-ANN algorithm suppresses only the peaks of the targeted subcarriers by slightly shifting the locations of their corresponding frequency samples without affecting their phase orientations. In turn, this achieves a reasonable system performance by sustaining a tolerable BER. For practical reasons and to cover a wide range of application scenarios, the threshold for the subcarrier peaks was chosen to be proportional to the saturation level of the nonlinear power amplifier used to pass the generated OFDM blocks. Consequently, the optimal values of the factor controlling the peak threshold were obtained that satisfy both reasonable PAPR reduction and acceptable BER levels. Furthermore, the proposed system does not require a recovery process at the receiver, thus making the computational process less complex. The simulation results show that the proposed system model performed satisfactorily, attaining both low PAPR and BER for specific application settings using comparatively fewer computations.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.11
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• pp.664-670
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• 2004

This paper presents a new velocity estimation strategy of a non-salient permanent magnet synchronous motor (PMSM) drive without high frequency signal injection or special PWM pattern. This approach is based on the d-axis current regulator output voltage of the drive system that has the information of rotor position error. The rotor velocity can be estimated through a rotor position tracking PI controller that controls the position error to zero. For zero and low speed operation, PI controller gains of rotor position tracking controller have a variable structure according to the estimated rotor velocity. In order to boost the bandwidth of PI controller around zero speed, a loop recovery technique is applied to the control system. The proposed method only requires the flux linkage of permanent magnet and is insensitive to the parameter estimation error and variation. The designers can easily determine the possible operating range with a desired bandwidth and perform the vector control even at low speeds. The experimental results show the satisfactory operation of the proposed sensorless algorithm under rated load conditions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.3
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• pp.475-481
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• 2009

The frequency and probability of deadlock are influential factors in the design of algorithms for deadlock. However, little work has been done in this area because it's not easy to analyze how factors such as the characteristics of process or resource, resource request and release patterns, or the number of process affect the occurrence of deadlock. This study was designed to reduce remarkably the number of state by adapting the model 'state (a,b)t' to represent the resource allocation state, as well as to include the effect of resource error rate and recovery rate in the system analysis. Various formulas about deadlock occurrence were resulted in this study such as the average time interval of deadlock, the probability that a process requesting a resource waits or deadlocks, and the probability that a request deadlocks in a cycle of length 2.

• Journal of IKEEE
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• v.23 no.3
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• pp.858-864
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• 2019

A clock system is proposed to eliminate data loss due to frequency difference between sensor nodes in a sensor utility network. The proposed clock system for each sensor node consists of a bust clock-data recovery (CDR) circuit, a digital phase-locked loop outputting a 32-phase clock, and a digital frequency synthesizer using a programmable open-loop fractional divider. A CMOS oscillator using an active inductor is used instead of a burst CDR circuit for the first sensor node. The proposed clock system is designed by using a 65 nm CMOS process with a 1.2 V supply voltage. When the frequency error between the sensor nodes is 1%, the proposed burst CDR has a time jitter of only 4.95 ns with a frequency multiplied by 64 for a data rate of 5 Mbps as the reference clock. Furthermore, the frequency change of the designed digital frequency synthesizer is performed within one period of the output clock in the frequency range of 100 kHz to 320 MHz.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.9
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• pp.723-732
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• 2016

This paper proposes an approach to fused navigation of an unmanned surface vehicle(USV) and to detection of the outlier or interference of global positioning system(GPS). The method fuses available sensor measurements through extended Kalman filter(EKF) to find the location and attitude of the USV. The method uses error covariance of EKF for detection of GPS outlier or interference. When outlier or interference of the GPS is detected, the method excludes GPS data from navigation process. The measurements to be fused for the navigation are GPS, acceleration, angular rate, magnetic field, linear velocity, range and bearing to acoustic beacons. The method is tested through simulated data and measurement data produced through ground navigation. The results show that the method detects GPS outlier or interference as well as the GPS recovery, which frees navigation from the problem of GPS abnormality.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.4
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• pp.167-177
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• 2010

Recent competitive and technological changes during the past decade have accelerated the need for better capital recovery methods. Competition and technology have together shortened the expected lives of property which could not have been forecasted several years ago. Since the usage of technological growth models has been prevalent in various technological forecasting environments, the various forms of growth models have become numerous. Of six such models studied, some models do significantly better than others, especially at low penetration levels in predicting future levels of growth. A set of criteria for choosing an appropriate model for technological growth models was developed. Two major characteristics of an S-shaped curve were elected which differentiate the various models; they are the skewness of the curve and underlying assumptions regarding the variance of error structure of the model.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.1017-1019
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• 1999

In this paper we present 2-dimensional image recovery method using Hadamard transform. Generally, the methods of Hadamard transform are more useful tools and much simplier than those of Fourier transform. The Hadamard transform can improve estimates when the detector is the source of noise. We take into account nonidealities in the system for the further improved image We also present the average mean square error(AMSE) associated with estimates with the results from computer simulations.