Sang Woo Kim - IEEE Xplore Author Profile

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This paper proposes a fault diagnosis method for a permanent magnet synchronous machine (PMSM) with an interturn short fault. The Interturn short fault degrades motor's performance and may lead to additional faults such as a demagnetization fault. In this paper, we suggest a diagnosis of the interturn short fault in PMSM using a Least Square method with voltage residual components. A rearranged fa...Show More
In this paper, an algorithm which estimates state-of-health of Li-ion battery based on impedance at low sampling rate is proposed. The algorithm includes a battery model with Warburg impedance instead of RC parallel circuit and recursive least square method for estimating the parameters. The parameters of the Warburg model and 1st order RC model at various aging cycles are analyzed. Compared with ...Show More
In technology of electronic packaging, demands of miniaturization and high-density in electronic systems has sustainably grown. Therefore, it have been required to develop the technology of three dimensional (3D) stacking using through silicon via (TSV) Technology. The TSV technology is an interconnection method by filling an electric conductive material in via hole after via formation. Cu as a fi...Show More
Demagnetization fault of Permanent magnet synchronous machine (PMSM) degrades motor's performance. As the strength of permanent magnet (PM) decreases, inductance of the PMSM changes since flux density affects electrical steel's nonlinear characteristics. It makes difficult to estimate exact flux linkages of the PMSM to diagnose demagnetization fault. In this paper, we suggested analytic inductance...Show More
A subband adaptive filter normalized least mean fourth criterion algorithm is proposed in which the fourth-order moments of subband error signals are minimized as cost functions. Simulation results verify that the proposed algorithm has a higher convergence rate than a conventional normalized subband adaptive filter algorithm in a non-Gaussian noise environment and for colored input signals.Show More
Wireless sensor networks are composed of a lot of sensor nodes and they are used to monitor environments. Since many studies on wireless sensor networks have considered a stationary sink node, they cannot provide fully ubiquitous applications based on a mobile sink node. In this paper, we forecasted mobile course through data communication between a mobile sink and fixed nodes and proposed plan to...Show More
In this study, we estimated slag foaming height from the vibration signal in an electric arc furnace (EAF). A fast Fourier transform (FFT) was used to determine the characteristics of the vibration signal in frequency spectrum. The reference height was obtained by analyzing an image of the slag gate. Finally, we developed an estimation model by using the least mean square (LMS) algorithm on the ba...Show More
This paper describes application-oriented text localization and character segmentation in images. Target texts in our application are often damaged by lots of various noise and, as a result, there are many unclear characters. Therefore, some special treatments are necessary to recognize these texts. In this paper, new optimized text localization and character segmentation algorithms are proposed. ...Show More
This paper proposes an efficient method to locate the automated guided vehicle (AGV) into the parking position using artificial visual landmark. For automated transshipment system in container terminals, the port AGV is used to transport containers autonomously and efficiently. To co-operate with the transfer crane, accurate guiding and positioning system is required. Using computer vision algorit...Show More
This paper presents a numerical expression for the excess mean-square error(EMSE) of affine projection(AP) algorithms, and the expression is proportional to the data reuse factor and the condition number of the input data. For the condition number, a recently reported technique developed by using E-norm is adopted instead of L2-norm. The proposed expression offers an insight into the mechanics of ...Show More
In this paper, we propose a support vector machine parameter tuning algorithm using dynamic encoding algorithm for handwritten digit recognition. This method uses dynamic encoding algorithm for search (DEAS) which is recently proposed optimization algorithm based on variable binary encoding length. The radius/margin bound is used for the estimation of the support vector machine generalization perf...Show More
OFDM (orthogonal frequency division multiplexing) communication is very attractive for high data rate transmission especially in the frequency selective fading channel. However, OFDM signal may be distorted by the nonlinear HPA (high power amplifier) since it has very high PAPR (peak-to-average power ratio). The proposed method is basically similar to the conventional SLM (selective mapping) metho...Show More
In this paper, we propose a fault diagnosis method for a group of distribution transformers using the graphical information of frequency responses. For a group of transformers with similar capacities and ratings, the patterns of transformer's magnitude plots appear to be almost identical with minor variations of amplitudes and locations of existing peaks and valleys in the plots. Therefore, it is ...Show More
In this paper, a new PAPR reduction method using correlation of input data sequence is proposed in order to overcome the serious drawbacks, such as necessity of side information transmission or increase of system complexity and calculation. A new PAPR reduction method can be classified into method 1 and method 2. Method 1 reduces the correlation between the smallest sub-sequence and neighbor small...Show More
High PAPR (peak to average power ratio) happens because of the summation of Walsh codes in the multicode CDMA (code division multiple access) communication system. In this paper, we propose a binary CA-MC-CDMA (constant amplitude multicode code division multiple access) system to solve the high PAPR problem. Unlike the conventional pre-coding method, there is no loss of bandwidth efficiency in the...Show More
When the ordinary least squares method is applied to the parameter estimation problem with noisy data matrix, it is well-known that the estimates turn out to be biased. While this bias term can be somewhat reduced by the use of models of higher order, or by requiring a high signal-to-noise ratio (SNR), it can never be completely removed. Consistent estimates can be obtained by means of the instrum...Show More
A newly developed optimization algorithm, called the dynamic encoding algorithm for searches (DEAS), is introduced and applied to the parameter identification of an induction motor for vector control and fault detection. Digital simulations are conducted on startup with no load and normal operation with load perturbations. DEAS is compared with the continuous-time prediction error method and the g...Show More
A transformer is one of the most important units in power networks; thus, fault diagnosis of transformers is quite significant. In this paper, the frequency-response analysis, deemed as a suitable diagnostic method for electrical and/or mechanical faults of a transformer, is employed to make a decision over a defective phase. To deal with wideband frequency responses of each phase, a synthetic spe...Show More
A novel version of the constrained affine projection (CAP) algorithm, referred to as the equally constrained affine projection (ECAP) algorithm is derived simultaneously to satisfy both the linear constraints and the residual conditions by means of the Lagrange method. In a geometrical view, the ECAP algorithm is interpreted to show a one-step optimization even with the parameter perturbation that...Show More
We study FD-OFDM (frequency diversity orthogonal frequency division multiplexing) system in the narrow-band jamming interference channel. Then, we propose an AFD-OFDM (adaptive FD-OFDM) to cope with the interference more adaptively. In FD-OFDM system, the information symbol of each parallel branch is multiplied by the orthogonal sequence and distributed into all subcarriers. So, each subcarrier tr...Show More
In recent times, the demodulator structure is reconfigurable for the SDR (software defined radio) technology that supports various communication reception modes in the radio communication. Owing to the SDR technology, it is possible to work in several modes without the peripheral hardware. We implement the M-ary FSK and BPSK demodulators on the DSP (TMS320C6203) board without the conventional comp...Show More
In this paper, we propose the PAPR (peak to average power ratio) reduction methods of SLM (selected mapping), and PTS (partial transmit sequence) to decrease the nonlinear distortion and to improve the power efficiency of the nonlinear HPA (high power amplifier) in the multi-code CDMA (code division multiple access) system. The phase rotation factors transmitted as side information in PTS and SLM ...Show More
This paper provides a technique to reduce the variation of exit thicknesses in a hot strip finishing mill. The feed-forward automatic gauge control (FFAGC) adjusts roll gap to reduce this variation by estimating the skid marks of exit slabs of previous stands. It plays a key role in FFAGC to filter the skid marks because it is difficult to exactly estimate the skid marks in the hard environment of...Show More
An induction motor is one of the most popular electrical apparatuses due to its simple structure and robust construction. Parameter identification of the induction motor has long been researched either for a vector control technique or fault detection. In this paper, a recently developed optimization algorithm is applied to the identification of whole unknown parameters in the mathematical equatio...Show More
In this paper, incremental fuzzy proportional integral (PI) speed and temperature controllers for a heavy-duty gas-turbine plant are presented. To improve performance, an analysis of incremental fuzzy PI control is provided, and new fuzzy control rules are proposed. In applying the fuzzy PI control to a gas-turbine plant, all gains are optimized by an adaptive genetic algorithm. We show the perfor...Show More