• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.525-530
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• 2013

With the increasing the importance of emotional quality of vehicle, the sound quality of systems with electric motor components has become increasingly important. Electric motors are used for windows, seats, sun roof, mirrors, steering columns, windshield wiper, climate control blowers, etc. In this paper, a study was conducted to identify sound quality factors that contribute to customer's satisfaction and preference of the window lift system. Jury test for subjective evaluation was carried out and sound quality index was developed. Averaged sound pressure level and sharpness were significant factors when glass moves down. Also, maximum loudness at stop section and averaged loudness were significant factor when glass moves up. Noise source identification was carried out for the reduced the loudness and sharpness during glass transferred section and impulsive noise at stop section, Using the source identification result, several improvement points were applied. And finally, the degree of sound quality improvement was judged using sound quality index.

• Asia-Pacific Journal of Business
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• v.11 no.3
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• pp.95-106
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• 2020

Purpose - This study examines the information effect of the disclosure of new office investments on the Korean stock market and investigates determinant of performance of sample firms. Design/methodology/approach - The sample consists of companies listed on the Korean Exchange that announced investments in new office construction for eleven-years from January 2007 to December 2017. It analyzes excess return using event study methodology and studies the determinants of abnormal return with multiple regression analysis. Findings - We find that abnormal returns of the short and long window are positive on average and statistically significant. In particular, CAR of high growth subsample is a larger positive return than that of the low one both short and long window. Difference in abnormal returns by investment size is observed only in short time window. But there is not observed difference by cash holding level. Research implications or Originality - This finding is able to be added to the evidence of the theory of corporate value maximization academically. Moreover, it shows the possibility that building a new office can have a positive effect on corporate value. It is expected to help investors make decisions because it can provide useful information to market participants in practice.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.1
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• pp.121-130
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• 2023

In children, large odontogenic cysts affect adjacent anatomical structures as well as displace developing permanent teeth. Odontogenic cysts are treated via enucleation or marsupialization. This case reports a 5-year-old boy and a 10-year-old boy who have not only displaced 3 or more permanent teeth but also elevated the maxillary sinus floor due to the large size of the cyst in the maxillary anterior region. In both cases, marsupialization was selected to minimize complications. After marsupialization, a customized acrylic obturator, window opening, and orthodontic traction for eruption guidance were gradually attempted, and it showed a good prognosis, so we report these cases.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.240-240
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• 2010

A multiple alloy metal nano-dots memory using FN tunneling was investigated in order to confirm its structural possibility for future flash memory. In this work, a multiple FePt nano-dots device with a high work function (~5.2 eV) and extremely high dot density (${\sim}\;1.2{\times}10^{13}/cm^2$) was fabricated. Its structural effect for multiple layers was evaluated and compared to one with a single layer in terms of the cell characteristics and reliability. We confirm that MOS capacitor structures with 2-4 multiple FePt nano-dot layers provide a larger threshold voltage window and better retention characteristics. Furthermore, it was also revealed that several process parameters for block oxide and inter-tunnel oxide between the nano-dot layers are very important to improve the efficiency of electron injection into multiple nano-dots. From these results, it is expected that a multiple FePt nano-dots memory using Fowler-Nordheim (FN)-tunneling could be a candidate structure for future flash memory.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.405-406
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• 2008

This paper presents a high performance 2D PE architecture for H.264 Motion Estimation(ME). While existing 2D PE architectures reuse the overlapped data of adjacent search windows scanned in 1 or 3-way, the new architecture scan adjacent windows and multiple paths instead of single raster and zigzag scanning of adjacent windows in 4 way(up,down,left,right). By reducing the redundant access factor by 1.4, the new 4-way search window improve the memory bandwidth by 70-58% compared with 1/3-way search window. With Altera Stratix-III implementation, the high performance 2D PE architecture deals with SD ($720{\times}480$) video of 2 reference frame, $48{\times}48$ search area and $16{\times}16$ macroblock by 30fps at 97.1MHz.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1487-1492
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• 2000

To identify forklift's booming noise in cabin under idling engine revolution, we discussed and applied conditioned input analysis. Acceleration signals at engine mounts and front window and rear window were considered as candidate input signals and output signal was sound pressure signal at driver's ear position in cabin. To reduce the numbers of the input signals, one idea were applied; Each one input signal from each input groups was selected, respectively because input signals in the same group were highly correlated. And Hilbert transform was used to determine the ordering of three selected inputs. Partial coherence functions, multiple coherence function and conditioned spectral density functions were investigate to the effects of booming noise by partial inputs.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.10
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• pp.611-617
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• 2003

A mechanical or electrical stimulation to the mandibular symphysis during a maximal voluntary clenching of the teeth always produces a jaw jerk followed by a silent period (transient stops) in the masseteric EMG (electromyogram). Generally, a mechanical stimulation is followed by a single silent period, and an electrical stimulation is followed by multiple silent periods. In this paper, we propose a new algorithm for determining the duration of the masseter silent period. The decision approach in essentially based upon a segmentation algorithm consisted of variance filter, median filter and gaussian filter. The new adaptive digital notch filter using R-CLMS(reverse constrained least mean-squared) algorithm is proposed for the elimination of powerline(60Hz) noise. At the same time, we design a real time measurement system for the EMG silent period under Window base.

• ETRI Journal
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• v.16 no.1
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• pp.17-34
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• 1994

In this paper, we present an architecture of the constant false alarm rate (CFAR) detector called the generalized order statistics (GOS) CFAR detector, which covers various order statistics (OS) and cell-averaging (CA) CFAR detectors as special cases. For the proposed GOS CFAR detector, we obtain unified formulas for the false alarm and detection probabilities. By properly choosing coefficients of the GOS CFAR detector, one can utilize any combination of ordered samples to estimate the background noise level. Thus, if we use a reference window of size N, we can realize $(2^N-1)$ kinds of CFAR processors and obtain their performances from the unified formulas. Some examples are the CA, the OS, the censored mean level, and the trimmed mean CFAR detectors. As an application of the GOS CFAR detector to multiple target detection, we propose an algorithm called the adaptive mean level detector, which censors adaptively the interfering target returns in a reference window.

• Smart Media Journal
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• v.7 no.4
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• pp.79-89
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• 2018

In recent years, falls among elderly people have gained serious attention as a major cause of injuries. Falls often lead to fatal consequences due to lack of prompt response and rescue. Therefore, a more accurate fall detection system and an effective feature extraction technique are required to prevent and reduce the risk of such incidents. In this paper, we proposed an efficient feature extraction technique based on multiple sliding windows and validated it through a series of experiments using supervised learning algorithms. The experiments were conducted using the public datasets obtained from tri-axial accelerometers. The results depicted that extraction of the feature from adjacent sliding windows led to high accuracy in supervised machine learning-based fall detection. Also, the experiments conducted in this study suggested that the best accuracy can be achieved by keeping the window size as small as 2 seconds. With the kNN classifier and dataset from wearable sensors, the experiments achieved accuracy rates of 94%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6B
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• pp.575-583
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• 2004

In this paper, we extend the multiple time scale control framework to the window-based congestion control, in particular, such as the TCP. This is performed by interfacing the TCP with a large time scale control module which adjusts the aggressiveness of the bandwidth consumption behavior exhibited by the TCP as a function of large time scale Self-Similar network state. i.e., conformation that exceeds the horizon of the feedback loop as determined by the RTT. How to effectively utilize such an information-due to its probabilistic nature, dispersion over the multiple time scales, and affection on the top of the existing window-based congestion controls-is a non-trivial problem. The evaluation performance of the multiple time scale TCP is facilitated by a simulation of the bench-mark environment which is based on the physical modeling of a self-similar traffic. We explicate our methodology for discerning and evaluating the impact of changes in transport protocols in the protocol stack under the self-similar traffic conditions. We discuss issues arising in the comparative performance evaluation under heavy-tailed workloads.