• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.383-386
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• 2005

This study proposes a case based reasoning system with two dimensional reduction techniques. In this study, vertical and horizontal dimensions of the research data are reduced through hybrid feature and instance selection process using genetic algorithms. We applied the proposed model to customer classification model which utilizes customers' demographic characteristics as inputs to predict their buying behavior for the specific product. Experimental results show that the proposed technique may improve the classification accuracy and outperform various optimized models of typical CBR system.

• ETRI Journal
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• v.44 no.3
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• pp.379-388
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• 2022

This study proposes a novel low-complexity algorithm for computing inverse fast Fourier transform (IFFT)/fast Fourier transform (FFT) operations in binary phase shift keying-modulated orthogonal frequency division multiplexing (OFDM) communication systems without requiring any twiddle factor multiplications. The peak-to-average power ratio (PAPR) reduction capacity of an efficient PAPR reduction technique, that is, H-SLM method, is evaluated using the proposed IFFT algorithm without any complex multiplications, and the impact of oversampling factor for the accurate calculation of PAPR is analyzed. The power spectral density of an OFDM signal generated using the proposed multiplierless IFFT algorithm is also examined. Moreover, the bit-error-rate performance of the H-SLM technique with the proposed IFFT/FFT algorithm is compared with the classical methods. Simulation results show that the proposed IFFT/FFT algorithm used in the H-SLM method requires no complex multiplications, thereby minimizing power consumption as well as the area of IFFT/FFT processors used in OFDM communication systems.

• Structural Engineering and Mechanics
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• v.10 no.6
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• pp.603-619
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• 2000

Analysis of a framed structure for vertical vibration requires a lot of computational efforts because large number of degrees of freedom are generally involved in the dynamic responses. This paper presents an efficient modeling technique for vertical vibration utilizing substructuring technique and super elements. To simplify the modeling procedure each floor in a structure is modeled as a substructure. Only the vertical translational degrees of freedom are selected as master degrees of freedom in the inside of each substructure. At the substructure-column interface, horizontal and rotational degrees of freedom are also included considering the compatibility condition of slabs and columns. For further simplification, the repeated parts in a substructure are modeled as super elements, which reduces computation time required for the construction of system matrices in a substructure. Finally, the Guyan reduction technique is applied to enhance the efficiency of dynamic analysis. In numerical examples, the efficiency and accuracy of the proposed method are demonstrated by comparing the response time histories and the analysis time.

• Journal of Magnetics
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• v.22 no.1
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• pp.55-59
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• 2017

The purpose of this study was to quantitatively evaluate image quality using intensity profile, coefficient of variation (COV), and peak signal to noise ratio (PSNR) with respect to noise reduction techniques in the ultrasound images. For that purpose, we compared with the median filter, Rudin-Osher-Fatemi (ROF), Anscombe and proposed patch group prior based denoising (PGPD) techniques. To evaluate image quality, the Shepp-Logan phantom and the ultrasound image were acquired using simulation and experiment, respectively. According to the results, the difference of intensity profile using PGPD technique is lowest compared with original Shepp-Logan phantom. In simulation, the measured COV was 0.249, 0.198, 0.198, 0.177, and 0.080 using noisy, median, ROF, Anscombe and PGPD technique, respectively. Also, in experimental image, the measured COV was 0.245, 0.230, 0.231, 0.242 and 0.187 using noisy, median, ROF, Anscombe and PGPD technique, respectively. Especially, when we used PGPD technique, the PSNR has highest value in both simulation and experiment. In this study, we performed simulation and experiment study to compare various denoising techniques in the ultrasound image. We can expect the PGPD technique to improve in medical diagnosis with excellent noise reduction.

• Journal of Korean Foot and Ankle Society
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• v.2 no.2
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• pp.82-87
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• 1998

The ankle is a complex structure supporting the entire musculoskeletal system during standing and walking. And so the goals of operative treatment for ankle fractures are to obtain an anatomical reduction that is maintained by stable fixation, resulting in a healed fracture and recovery of normal function. The 64 patients who had ankle fractures were treated by arthroscopic reduction(20 cases) and open reduction (43 cases) in Konkuk university hospital from February 1991 to October 1997 and the results were analyzed in clinical and radiological aspects. The following results were obtained. According to the criteria of Meyer, arthroscopic assisted reduction group had good or excellent results in 18 cases (90%) and open reduction group good or excellent in 35 cases (83%). The difference of the results was not significant statistically, but arthroscopic assisted reduction technique has several advantages over open technique; the best assessment of articular surface, lower wound problem, postoperatively faster rate of rehabilitation and minor discomfort.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.11a
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• pp.31-37
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• 2006

The objective of this research is to select the most effective technique from task related techniques(motion & time study, job redesign, physical environment improvement) for improving work efficiency in shipbuilding enterprise. This study consists of several principal steps. The first step is to design critical criteria in evaluating work efficiency in shipbuilding enterprises. The second step is to develop sub-criteria of the critical criteria. The third step is to develop a four level AHP(Analytic Hierarchy Process)structure using the critical criteria, sub-criteria and techniques from task related techniques. The fourth step is to develop the pairwise comparison matrix by each level of AHP structure, which was based on survey data collected at the H heavy industry. And the last step is to select the most effective technique from task related techniques using AHP analysis. The result of AHP analysis has shown clear difference in priority among task related techniques in terms of work efficiency of the shipbuilding enterprise: The reduction of normal time has more importance than the reduction of allowance time, motion & time study techniques are most important for the reduction of normal time, physical environment improvement is most important for the reduction of allowance time as well.

• Journal of The Korean Dental Society of Anesthesiology
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• v.12 no.2
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• pp.69-74
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• 2012

Background: The purpose of this study is to investigate the efficacy and safety of the sedation technique for implant surgery by combining the use of inhalation of nitrous oxide/oxygen with intravenous midazolam. Methods: Patients requiring surgery for the placement of dental implants were randomly allocated to two groups receiving intravenous midazolam or a combined technique using nitrous oxide/oxide and intravenous midazolam. Safety parameters, cooperation scores, anxiety scales, total amount of midazolam administered and recovery time were recorded and compared. Results: There were a statistically significant reduction in the amount of midazolam required to achieve optimal sedation (P<0.01), an overall significant reduction in recovery time (P<0.01), a significant reduction in anxiety scales (P<0.05), and a significant improvement in cooperation (P<0.05) and peripheral oxygen saturation (P<0.05) when a combined technique of inhalational $N_2O/O_2$ and midazolam was used. Conclusions: For implant surgery, this combining sedation technique could be safe and reliable, demonstrating reduction of total dose of midazolam and level of patient's anxiety and improvement in patient's recovery and cooperation.

• Journal of Construction Engineering and Project Management
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• v.5 no.2
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• pp.24-34
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• 2015

The complexity arises in defining the construction quality due to its perception, based on inherent market conditions and their requirements, the diversified stakeholders itself and their desired output. A quantitative survey based approach was adopted in this constructive study. A questionnaire based survey was conducted, for the assessment of construction quality perception and expectations in the context of quality improvement technique. The survey feedback of professionals, from the leading construction organizations/companies of Pakistan were analyzed. The financial capacity, organizational structure, and construction experience of the construction firms formed basis for their selection. After statistical analysis of survey feedback it was found reliable and valid for the inferential purpose to the target population of construction professionals. The quality perception was found to be project scope oriented, considered as an excess cost for a construction project and keeping the rework minimum by qualifying the required quality tests, keeping the defects minimum by ensuring the specifications of supplied material. Any quality improvement technique was expected to address the financial aspects of the construction project for the employer and contractor, by increasing the profitability through reduction in overall cost, reduction in time, reduction in defects and improving the productivity in a construction project. The study is beneficial for the construction professionals to assess the prevailing construction quality perception and the expectations from implementation of any quality improvement technique in construction projects.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.10
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• pp.1014-1022
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• 2014

In mechatronic systems using electric signals to drive control systems, driving signals including the frequency band of the unwanted signals, such as resonant frequencies and noise frequencies, can affect the accuracy of the controlled system and can cause serious damage to the system due to the resonance phenomenon of the mechatronic system. An LOS (Line of Sight) control unit is used to automatically rotate the gimbal system with a video imaging system generally mounted on modern aerial vehicles. However, it still suffers from natural frequency variation problems due to variations of operational temperature. To prevent degradation in performance, this paper proposes an adaptive filtering technique based on real-time noise analysis and adaptive notch-filtering for LOS control systems, and verifies how our proposed method maintains the LOS stabilization performance. Additionally, this filtering technique can be applied to the image noise filtering of the video imaging system. It is designed to reduce image noises generated by switching circuits or power sources. The details of design procedures of the proposed filtering technique and the experiments for the performance verification are described in this paper.

• Smart Structures and Systems
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• v.13 no.1
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• pp.99-109
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• 2014

The goal of any Model Order Reduction (MOR) technique is to build a model of order lower than the one of the real model, so that the computational effort is reduced, and the ability to estimate the input-output mapping of the original system is preserved in an important region of the input space. Actually, since only a subset of the input space is of interest, the matching is required only in this subset of the input space. In this contribution, the consequences on the achieved accuracy of adopting different reduction technique patterns is discussed mainly with reference to a linear case study.