• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.5
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• pp.543-548
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• 2014

Multiple-model based speech recognition framework (MMSR) has been known to be very successful in speech recognition. Since it uses multiple hidden Markov modes (HMMs) that corresponds to various noise types and signal-to-noise ratio (SNR) values, the selected acoustic model can have a close match with the test noisy speech. However, since the number of HMM sets is limited in practical use, the acoustic mismatch still remains as a problem. In this study, we experimentally determined the optimal SNR mapping between the test noisy speech and the HMM set to mitigate the mismatch between them. Improved performance was obtained by employing the SNR mapping instead of using the estimated SNR from the test noisy speech. When we applied the proposed method to the MMSR, the experimental results on the Aurora 2 database show that the relative word error rate reduction of 6.3% and 9.4% was achieved compared to a conventional MMSR and multi-condition training (MTR), respectively.

• Journal of the Korean Society of Systems Engineering
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• v.9 no.1
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• pp.65-84
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• 2013

This paper introduces a systems engineering approach to reliability centered maintenance to address some of the weaknesses. Reliability centered maintenance is a systematic, disciplined process that produces an efficient equipment management strategy to reduce the probability of failure [1]. The study identifies the need for RCM, requirements analysis, design for RCM implementation. Value modeling is used to evaluate the value measures of RCM. The system boundary for the study has been selected as containment spray pump and its motor drive. Failure Mode and Criticality Effects analysis is applied to evaluate the failure modes while the logic tree diagram used to determine the optimum maintenance strategy. It is concluded that condition based maintenance tasks should be enhanced to reduce component degradation and thus improve reliability and availability of the component. It is recommended to apply time directed tasks to age related failures and failure finding tasks to hidden failures.

• Journal of the Korean Society of Clothing and Textiles
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• v.18 no.3
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• pp.368-386
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• 1994

The primary purpose of this study was to identify the diversity and embellishment of American Indian clothing and relationship between culture and clothing in American Indian Culture Areas. After the introduction of European material culture, change in American Indian clothing was conducted. The result of the Study as follows: 1. The most influential factors affecting the diversity of American Indian clothing were environmental factors. Climates and geographical features, Raw material were reflected in clothing style and clothing material in each culture Area. 2. Economic situation and life style were shown to be influential to clothing development. The best known instance of this was greatly elaborated clothing and personal adornment of the Plains who had higher stand of life and nomadic life style. 3. Religious concepts were important factors influencing American Indian clothing. Indian tribes had different ritual performance they used particular motifs in clothing. Clothing, such as "ghost shirt", Apache medicine shirt and Pueblo ceremonial clothing, served hidden pur- poses. 4. Techenology was another factor identified in this study as influencing American Indian clothing. Especially, weaving skills of Southwest played a great role in textile development. Pueblo "manta" and Navaho "bil" were famous for Indian costume. 5. European material culture allowed great change of traditional native Indian clothing. American Indian had new material, new styles, new concept of clothing. 6. American Indian, although Indian applicated European trade goods, was actually quite conservative in retaining traditional designs and modes of decoration. Asthetics and traction of American Indian were reflected in American Indian clothing.d in American Indian clothing.

• Applied Microscopy
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• v.50
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• pp.25.1-25.11
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• 2020

Scanning acoustic microscopy (SAM) or Acoustic Micro Imaging (AMI) is a powerful, non-destructive technique that can detect hidden defects in elastic and biological samples as well as non-transparent hard materials. By monitoring the internal features of a sample in three-dimensional integration, this technique can efficiently find physical defects such as cracks, voids, and delamination with high sensitivity. In recent years, advanced techniques such as ultrasound impedance microscopy, ultrasound speed microscopy, and scanning acoustic gigahertz microscopy have been developed for applications in industries and in the medical field to provide additional information on the internal stress, viscoelastic, and anisotropic, or nonlinear properties. X-ray, magnetic resonance, and infrared techniques are the other competitive and widely used methods. However, they have their own advantages and limitations owing to their inherent properties such as different light sources and sensors. This paper provides an overview of the principle of SAM and presents a few results to demonstrate the applications of modern acoustic imaging technology. A variety of inspection modes, such as vertical, horizontal, and diagonal cross-sections have been presented by employing the focus pathway and image reconstruction algorithm. Images have been reconstructed from the reflected echoes resulting from the change in the acoustic impedance at the interface of the material layers or defects. The results described in this paper indicate that the novel acoustic technology can expand the scope of SAM as a versatile diagnostic tool requiring less time and having a high efficiency.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.4
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• pp.287-293
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• 2005

Ultrasonic guided waves are gaining increasing attention for the inspection of platelike and rodlike structures. At the same time, inspection methods that do not require contact with the test piece are being developed for advanced applications. This paper capitalizes on recent advances in the areas of guided wave ultrasonics and noncontact ultrasonics to demonstrate a superior method for the nondestructive detection of defects thinning simulating hidden corrosion in thin aluminum plates. The proposed approach uses EMAT(electro-magnetic acoustic transducer) for the noncontact generation and detection of guided waves. Interesting features in the dispersive behavior of selected guided modes are used for the detection of plate thinning. It is shown that mode cutoff measurements provide a qualitative detection of defects thinning. Measurement of the mode group velocity can be also used to quantify depth thinning.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.11
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• pp.5338-5359
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• 2017

In-band full-duplex (IBFD) wireless communication supports symmetric dual transmission between two nodes and asymmetric dual transmission among three nodes, which allows improved throughput for distributed IBFD wireless networks. However, inter-node interference (INI) can affect desired packet reception in the downlink of three-node topology. The current Half-duplex (HD) medium access control (MAC) mechanism RTS/CTS is unable to establish an asymmetric dual link and consequently to suppress INI. In this paper, we propose a medium access control mechanism for use in distributed IBFD wireless networks, FD-DMAC (Full-Duplex Distributed MAC). In this approach, communication nodes only require single channel access to establish symmetric or asymmetric dual link, and we fully consider the two transmission modes of asymmetric dual link. Through FD-DMAC medium access, the neighbors of communication nodes can clearly know network transmission status, which will provide other opportunities of asymmetric IBFD dual communication and solve hidden node problem. Additionally, we leverage FD-DMAC to transmit received power information. This approach can assist communication nodes to adjust transmit powers and suppress INI. Finally, we give a theoretical analysis of network performance using a discrete-time Markov model. The numerical results show that FD-DMAC achieves a significant improvement over RTS/CTS in terms of throughput and delay.

• International Commerce and Information Review
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• v.15 no.4
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• pp.341-366
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• 2013

The term, Mittelstand, has no exact english translation for the definition, but, today, Mittelstand refers to small and medium-sized enterprises(SME), mostly family-owned firms in Germany. The Mittelstand is called the backbone of the German economy because it drove the economic miracle after World War II. During the global recession and the euro zone's debt crisis in recent years, in which european businesses have faced the near-collapse of competitiveness particularly in manufacturing, the German exports are booming and exceeded exports of China in 2012. Most importantly, the Germany economic performance has been widely attributed to the strength of the Mittelstand. Many of countries, even some leading public companies are seeking to emulate the success of the Mittelstand. Investors evaluate that many of Germany's investable "hidden champions" are Mittelstand companies. The purpose of this study is to present some of answers to the following questions: Firstly, what makes the German Mittelstand so successful? Secondly, what does the success of the German Mittelstand mean for the Korean SMEs in global competitiveness? Thirdly, what Korean government has to do improve the global competitiveness of the Korean SMEs? Some discussions in this study mention the managerial implications for Korean exporting SMEs particularly in manufacturing. Several factors that account for the success of the German Mittelstand are technological excellence and the tradition of family-owned management, concentration on niche market and globalization, and institutional supports. There are some of important lessons to be learned from the German Mittelstand. If the purposes of Korean SMEs want to remain in the sustainable competitive advantage and withstand unforeseen economic turbulences in the future, they must be able to meet the followings: 1) Technology that meets the global standard or exceeding it 2) Competitiveness in price in the global market 3) Active involvement in the globalization process, utilizing various entry modes Innovative products at globally competitive price are a crucial point for Korean exporting SMEs to achieve their competitive edge over others in the target markets abroad. It is time for Korean SMEs to cultivate a core competence in manufacturing in order to position Korea as a global manufacturing hub with SMEs leading.

• Journal of Korean Classical Literature and Education
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• no.33
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• pp.211-253
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• 2016

Depending on the class and status, literary works are variously accepted and interpreted. As a result, they show different forms and ways of enjoying the novels and different variations of a text. The only ideal way of investigating and analyzting it is to meet someone who actually lived in that era. This study tries to investigate the enjoying aspects of the classic Korean classical novels by studying how the classical novels have been enjoyed in Northern Gyeong-Buk Area, especially in Cheongsong. It is a follow-up study of cases studies based in Yeongdeok, Uljin. As a result, one can come true the conclusions. In the case of Cheongsong, the Northern Area and Southern Areas show differences in their modes enjoying the Korean classical novels. The Northern Area has a strong expresses self-confidence and pride, and forms solid enjoying groups. However I could hardly find any such cases in the Southern Area. And the entertaining aspects of the classical novels are enjoyed by individuals rather than entertainers. It shows that there have been many difficulties in the culture of in taking-root classical novels as a firm ludic culture in Cheongsong. Furthermore, this survey can identify a duality of entertainers genres conception to enjoying Ga-sa and classic the Korean classical novels. The entertainers who haves read only the classical novels has not hidden ashamed of themselves as readers and entertainersof them. But the entertainers who are proud of the self as enjoyers of Ga-sa tried to dissimulate hide the fact that they read of the classical novels, because they think that a narrativity and fictitiousness, incredibility of the novels are disproportionate inappropriate to their for dignity as members of Yangban(兩班) families, and are in stark contrast to the morality and seriousness of Ga-sa.