• Journal of Broadcast Engineering
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• v.27 no.6
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• pp.840-847
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• 2022

In a deep neural network (DNN)-based speech enhancement, using global and local input speech information is closely related to model performance. Recently, a nested U-Net structure that utilizes global and local input data information using multi-scale has bee n proposed. This nested U-Net was also applied to speech enhancement and showed outstanding performance. However, a single skip connection used in nested U-Nets must be modified for the nested structure. In this paper, we propose a multi-level skip connection (MLS) to optimize the performance of the nested U-Net-based speech enhancement algorithm. As a result, the proposed MLS showed excellent performance improvement in various objective evaluation metrics compared to the standard skip connection, which means th at the MLS can optimize the performance of the nested U-Net-based speech enhancement algorithm. In addition, the final proposed m odel showed superior performance compared to other DNN-based speech enhancement models.

• Korean journal of communication and information
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• v.45
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• pp.255-295
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• 2009

The purpose of this study was to investigate how much multi-cultural traits the multiculture-oriented TV programs would have and how they tended to represent it with what kinds of meaning structures. As an object of this study, the authors chose the Program of KBS-TV which had been discussed seriously to raise a multi-cultural issue as well as a sexuality issue of lady guests. They collected 70 weekly programs from Nov. 26 of 2006 to March 31, 2008, and finally selected and analyzed 5 weekly programs as main analytic data. They tried to analyze them with various semiotic research methods, especially, linguistic semiotic research methods and pictorial research methods. As results of this study, it was found that this Program was based on multiful-levels of meaning structure: that is, superficial level, representation level and in-depth level. The superficial level of this program presented various multi-cultural traits through many and various talks of lady guests. Its representation level indicated some patterns of discourses about issues and agendas of the talks among lady guests. The in-depth level was based on the sexuality of lady guests as well as the male-dominant ideology. It was finally implicated that this Program was based on the sexuality and feminity of lady guests even though it tried to advocate its multi-cultural traits.

• Journal of the Korean Geographical Society
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• v.38 no.5
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• pp.667-685
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• 2003

To address the requirements of gap analysis for species protection, as well as the needs of state and federal agencies for detailed digital land cover, a 43-class map at the vegetation alliance level was created for the state of Kansas using multi-temporal Thematic Mapper imagery. The mapping approach included the use of three-date multi-seasonal imagery, a two-stage classification approach that first masked out cropland areas using unsupervised classification and then mapped natural vegetation with supervised classification, visualization techniques utilizing a map of small multiples and field experts, and extensive use of ancillary data in post-hoc processing. Accuracy assessment was conducted at three levels of generalization (Anderson Level I, vegetation formation, and vegetation alliance) and three cross-tabulation approaches. Overall accuracy ranged from 51.7% to 89.4%, depending on level of generalization, while accuracy figures for individual alliance classes varied by area covered and level of sampling.

• Journal of Preventive Medicine and Public Health
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• v.45 no.2
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• pp.90-97
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• 2012

Objectives: While there have been many quantitative studies on the public's attitude towards mental illnesses, it is hard to find quantitative study which focused on the contextual effect on the public's attitude. The purpose of this study was to identify factors that affect the public's beliefs and attitudes including contextual effects. Methods: We analyzed survey on the public's beliefs and attitudes towards mental illness in Korea with multi-level analysis. We analyzed the public's beliefs and attitudes in terms of prejudice as an intermediate outcome and social distance as a final outcome. Then, we focused on the associations of factors, which were individual and regional socioeconomic factors, familiarity, and knowledge based on the comparison of the intermediate and final outcomes. Results: Prejudice was not explained by regional variables but was only correlated with individual factors. Prejudice increased with age and decreased by high education level. However, social distance controlling for prejudice increased in females, in people with a high education level, and in regions with a high education level and a high proportion of the old. Therefore, social distance without controlling for prejudice increased in females, in the elderly, in highly educated people, and in regions with a high education and aged community. Conclusions: The result of the multi-level analysis for the regional variables suggests that social distance for mental illness are not only determined by individual factors but also influenced by the surroundings so that it could be tackled sufficiently with appropriate considering of the relevant regional context with individual characteristics.

• Journal of the Korea Society for Simulation
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• v.24 no.1
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• pp.9-16
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• 2015

In this paper, the multi-resolution simulation of standard linkage architecture is consists of the engineering-level (QUEST), engagement-level (SADM), the mission-level (EADSIM). It was developed the engineering-level model using battle experiment integrated development environment in the battle experimental engineering system. The engagement level model was developed using the SADM and the mission-level model was developed using EADSIM. The standard linkage architecture is designed and implemented in order to interlocking model of multiple layers. Each different simulation programs in a distributed environment was designed by HLA interface specifications for satisfying interworking. Also the integrated interoperation gateway was developed for relaying the each different simulation programs. The effective naval weapon system for measure of effectiveness develops using to improve the fidelity of the model between the various layers through multi-resolution interoperation simulation. According to the operator requirement is quickly battlefield environment can be constructed. The other simulation program that being designed through standards linkage architecture can linkage easily and efficiently.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.6
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• pp.469-477
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• 2003

This paper proposes a Carrier-Rotation (CR) PWM technique that is a new solution for the voltage unbalancing problem of flying capacitors in the Flying Capacitor Multi-level Inverter (FCMI). The proposed technique equalizes the utilization of phase leg voltage redundancies corresponding to the charging and the discharging state of individual flying capacitors during each switching period of all the switches. Therefore, the charging and the discharging quantity of flying capacitors are equal, which makes the average variation of flying capacitor voltages become zero and keeps their voltage stable during minimum specified period. It also has the reduced harmonic contents of output voltage and the same switch utilization since all the carrier signals are in phase and the switching frequency of each switch is identical. The proposed technique is analyzed precisely in flying capacitor 3-level inverter and then it has expanded to the FCMI (N-level, N>3). Experimental results on the laboratory prototype flying capacitor 3-level inverter confirm the validity of the proposed technique.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.5
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• pp.673-680
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• 2017

In the proposed paper, we designed low noise frequency synthesizer with compact size for Multi-Band. The proposed frequency synthesizer consists of fundamental frequency band(2 GHz) and harmonic frequency band(4 GHz). To improve the phase noise and spurious level of frequency synthesizer, we analyze how the configuration of frequency synthesizer affect the phase noise and design the multi-band's structure. The implemented frequency synthesizer reduce both the phase noise and spurious level. The phase noise is -92.17 dBc/Hz at 1 kHz frequency offset in 2 GHz and -90.50 dBc/Hz at 1 kHz frequency offset in 4 GHz. All spurious signals including fundamental frequency are suppressed at least 20 dBc than the second harmonic frequency.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.489-492
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• 2005

As a former level of MSC(Multi Spectral Camera) telescope of the KOMPSA T2satellite, the several performance tests of EOS(Electro Optical Subsystem) were performed in the EOS level. By these tests, not only the design requirement of payload can be verified but also the test result can be the important criterion to estimate the performance of payload in the launch and space orbit environment. The EOS Geometric Mapping test is to verify the accuracy of the alignment & assembly on the Subsystem of the MSC by measurement like these; LOS(Line of Sight), LOD(Line of Detector), Band to Band Registration, Optical Distortion and Reference Cube. This paper describes the test results and the analysis for the EOS Geometric Mapping.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.1
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• pp.97-102
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• 2011

This study was performed to design and develop an ergonomic equipment for strawberry sorting and packing in agricultural working environments. Potential risk of work related musculo-skeletal disorders associated with farm workers performing strawberry sorting and packing was analyzed through interviews, field surveys, work measurement, and working posture evaluation. For the evaluation of working posture, we used REBA, OWAS, and RULA assessment methods to identify multi-factorial risk factors. Based on the result of comprehensive assessment, a new concept of multi-level rotating table for strawberry sorting and packing was proposed to modify awkward working postures and improve the effectiveness of the farm work. Finally, the characteristics and effectiveness of new equipment was discussed in terms of improvements in productivity, safety, and subjective ratings of farm workers. The results of analysis showed that working conditions improved significantly.

• Korean Management Science Review
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• v.28 no.1
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• pp.117-127
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• 2011

In the Multi-Echelon maintenance environment, METRIC(Multi-Echelon Technique for Repairable Item Control) has been used in several different inventory level selection models, such as MOD-METRIC, Vari-METRIC, and Dyna- ETRIC. While this model's logic is easy to be implemented, a critical assumption of infinite maintenance capacity would deteriorate actual values, especially Expected Back Order(EBO)s for each item. To improve the accuracy of EBO, we develop two models using simulation and queueing theory that calculates EBO considering finite capacity. The result of our numerical example shows that the expected backorder from our model is much closer to the true value than the one from Vari-METRIC. The queueing model is preferable to the simulation model regarding the computational time.