• The Journal of the Acoustical Society of Korea
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• v.39 no.2
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• pp.131-136
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• 2020

Wake Up Word (WUW) is a short utterance used to convert speech recognizer to recognition mode. The WUW defined by the user who actually use the speech recognizer is called user-defined WUW. In this paper, to recognize user-defined WUW, we construct traditional Gaussian Mixture Model-Hidden Markov Model (GMM-HMM), Linear Discriminant Analysis (LDA)-GMM-HMM and LDA-Deep Neural Network (DNN)-HMM based system and compare their performances. Also, to improve recognition accuracy of the WUW system, a threshold method is applied to each model, which significantly reduces the error rate of the WUW recognition and the rejection failure rate of non-WUW simultaneously. For LDA-DNN-HMM system, when the WUW error rate is 9.84 %, the rejection failure rate of non-WUW is 0.0058 %, which is about 4.82 times lower than the LDA-GMM-HMM system. These results demonstrate that LDA-DNN-HMM model developed in this paper proves to be highly effective for constructing user-defined WUW recognition system.

• Journal of the Korean Chemical Society
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• v.37 no.11
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• pp.967-973
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• 1993

${\alpha},{\omega}$-Diols such as 1,6-hexanediol and 1,7-heptanediol react with secondary amines in the presence of catalytic amount of ruthenium complex at 180$^{\circ}$C for 24 hrs to give the corresponding diamino compounds in good yields. The yield of diamino compound was affected by the molar ratio of ${\alpha},{\omega}$-diol to secondary amine. The reaction was also affected by the nature of the phosphorus ligands employed. On the other hand, aromatic primary amines react with 1,2,6-hexanetriol in the presence of RuCl_3{\cdot}H_2O-3PPh_3$ at 180$^{\circ}$C for 3 hours under argon atmosphere to give selectively 1-substituted aryl-3-hydroxyperhydroazepines in good yields. Selective synthesis of these products show that two primary hydroxy groups (1,6-positions) oxidize predominantly than secondary hydroxy group (2-position) by ruthenium-phosphorus complex. The yields were decreased according to the order of para-, meta- and ortho-substituent.

• Journal of the Korea Society of Computer and Information
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• v.19 no.8
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• pp.139-150
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• 2014

In this essay, we hoped to see how the operational university job database systems perform badly, since there are a lot of signs that they fall short of data design fundamentals. Fortunately, we are able to choose a university employment support database(UESD) application as a candidate for our study. We have taken UESD system as it is and we have developed an enhanced version of the UESD system, which strictly followed the basic fundamentals in data modeling and named it as NewUESD system. Then, we have conducted a comparison to see how much UESD system is deviated from the standard balancedness found in NewUESD. From the perspective of data obesity, we computed how much UESD contains unnecessary data. The NewUESD contained no unnecessary data at all, which implies that it has only data that is necessary to form a data model. But the data obesity of UESD system is found to be more than 50%. Therefore, it is significantly higher, 37% higher in this case, than the obesity judged to be normal, which is 19% in NewUESD system.

• Journal of the Korean Vacuum Society
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• v.16 no.4
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• pp.250-261
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• 2007

We present the morphological evolution at different source powers in the ion-enhanced etching of GaAs(100) in $BCl_3-Cl_2$ plasma. With little ion bombardment at floating potential, the surface develops <110> ridges and {111} facets, as it does in purely chemical etching. Higher source power (900 W) produces well developed crystallographic surfaces while lower source power (100 W) produces poorly developed crystallographic surfaces. This is attributed to the availability of excited reactive species (chlorine atoms) depending on source powers. With more concentration of the reactive species at higher source powers, the surface of GaAs(100) would be a surface that is expected from thermodynamics while the surface morphology would be determined by sputtering in the lack of reactive species. Statistical analysis of the surfaces, based on scaling theory, revealed two spatial exponents: one (smaller than one) is formed by atomic scale mechanisms, the other (larger than one) is formed by larger scale mechanisms which is believed to develop facets. When samples are biased, the surfaces experienced bombardment resulting in suppression of ridge formation at high source power and islands formation at low source power.

• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.18-22
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• 2006

Effects of V substitution of Fe on the magnetic properties of $Fe_3O_4$ have been investigated by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), conversion electron Mossbauer spectroscopy (CEMS), and vibrating sample magnetometry (VSM) measurements on sol-gel-grown films. XRD data indicates that the $V_xFe_{3-x}O_4$ films maintain cubic structure up to x=1.0 with little change of the lattice constant. Analyses on V 2p and Fe 2p levels of the XPS data indicate that V exist as $V^{3+}$ mostly in the $V_xFe_{3-x}O_4$ films with the density of $V^{2+}$ ions increasing with increasing V content. Analyses on the CEMS data indicate that $V^{3+}$ ions substitute tetrahedral $Fe^{3+}$ sites mostly, while $V^{2+}$ ions octahedral $Fe^{2+}$ sites. Results of room-temperature VSM measurements on the films reveal that the saturation magnetization for the x=0.14 sample is larger than that of $Fe_3O_4$, while it becomes smaller than that of $Fe_3O_4$ for $x{\geq}0.5$. The coercivity of the $V_xFe_{3-x}O_4$ films is found to increase with x, attributed to the increase of anisotropy by the substitution of $V^{2+}(d^3)$ ions into the octahedral sites.

• The Journal of Korean Academy of Sensory Integration
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• v.12 no.2
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• pp.13-24
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• 2014

Objective : The purpose of this research is to choose scissoring, handling chopsticks, wearing a jacket with buttons as a significant subject in order to understand relations between writing ability of a preschool child and functional achievement ability. Methods : The subjects are 66 preschool children under the age of 5. The research has conducted for 1 week by using writing test, scissoring, handling chopsticks, wearing a jacket with buttons as an indicator of valuation. We collected statistics by using program called SPSS WIN 14.0 for the process of analysis. Results : The score of writing ability which is one of the common characteristic of subject has a significant difference in terms of statistics according to the gender. the score of girls are higher($13.33{\pm}2.55$) than boys($11.92{\pm}2.52$). Writing ability has a significant relativity with the achievement ability of scissoring(r=0.244, p=0.048),handling chopsticks(r=0.403, p=0.001), achievement ability in terms of statistics. Conclusion : A significant difference between writing ability according common characteristics of children is showed based on the gender. writing ability has a significant relativity with the achievement ability of scissoring, handling chopsticks, achievement ability.

• Journal of the Korean Magnetics Society
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• v.16 no.6
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• pp.283-286
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• 2006

We have studied the role of ${\alpha}-Al_{2}O_{3}$ buffer layer as a diffusion barrier in the Ba-ferrite/$SiO_{2}$ magnetic thin films for high-density recording media. In the interface of amorphous Ba-ferrite $(1900-{\AA}-thick)/SiO_{2}$ thin film during annealing, the interfacial diffusion started to occur at ${\sim}700^{\circ}C$. As the annealing temperature increased up to $800^{\circ}C$, the interfacial diffusion abruptly proceeded resulting in the high interface roughness and the deterioration of the magnetic properties. In order to control the interfacial diffusion at the high temperature, we introduced ${\alpha}-Al_{2}O_{3}$ buffer layer ($110-{\AA}-thick$) in the interface of Ba-ferrite/$SiO_{2}$ thin film. During the annealing of Ba-ferrite/${\alpha}-Al_{2}O_{3}/SiO_{2}$ thin film even at ${\sim}800^{\circ}C$, the interface was very smooth. The magnetic properties, such as saturation magnetization and intrinsic coercivity, were also enhanced, due to the inhibition of interfacial diffusion by the ${\alpha}-Al_{2}O_{3}$ buffer layer. Our study suggests that the ${\alpha}-Al_{2}O_{3}$ buffer layer act as a useful interfacial diffusion barrier in the Ba-ferrite/$SiO_{2}$ magnetic thin films.

• Journal of the Korean Society for Railway
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• v.11 no.4
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• pp.357-363
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• 2008

This study investigates the durability of carbon/epoxy composites for use on train car bodies under a salt water spray environment. Salt water solution with 5% NaCl, similar to natural salt water, was used for the salt water environmental tests. The specimens were obtained from a composite panel consisting of an epoxy matrix reinforced with T700 carbon fabric. The specimens were exposed to the salt water environment for up to 12 months. Mechanical tests were performed to obtain tensile properties, flexural properties, and shear properties. Dynamic mechanical analysis was used to measure such thermal properties as storage modulus, loss modulus, and tan $\delta$. Also FT/IR tests were conducted to investigate changes in chemical structure with exposure. The results revealed that fiber-dominated mechanical properties were not affected much by exposure time, but matrix-dominated mechanical properties decreased with increasing exposure time. Storage modulus was not very sensitive to exposure time, but glass transition temperature was affected, slightly decreasing with increasing exposure time. Although the peak intensity of FT/IR curves was affected slightly by exposure time, the peak shape and peak location of FT/IR curves were not noticeably changed. Carbon/epoxy composites used for this study were relatively stable to the salt water environment.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.6
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• pp.567-580
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• 2016

In recent years, our society, because of the arrival of a new paradigm according to the rapid changes in ICT has entered into future smart society and the ubiquitous era. So it can be a notable turning point in the marine disaster prevention system with big data, aspects of the era change. Therefore, this study was to derive a desirable vision for the big data marine disaster prevention informatization in terms of ICT maritime disaster prevention system development as preparedness for the maritime disaster by applying 'scenario planning' as a foresight method. Soon this study derived a successful marine disaster prevention informatization strategy as preparedness for the maritime disaster like Ferry Sewol Disaster. It proposed the big data marine disaster prevention informatization system with the use of the administrative aspects of information with spatial informatization as big data information. Also this study explored the future leadership strategy of the big data marine disaster prevention informatization in smart society. Eventually in 2030 to around, In order to still remain our marine disaster prevention informatization as a leading ICT nation, this study suggested the following strategy. It is important to ready the advanced Big Data administrative spatial informatization system In terms of prevention of incidents like Ferry Sewol Disaster.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.4
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• pp.803-812
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• 2018

The Morse code was firstly used for a wire telegraph service on May 1884 in USA. After about 10 years Korean researchers developed the Morse code in 1884 and the Morse code was firstly introduced in Korea for the wire telegraph service in September 1885. For about 130 years later, the Hangul Jamo Morse code has been used without any serious modification up to now. The Morse code is the variable length code system which each codes have a different code length. The related reference shows that English alphabet Morse code was applied in the coding theory. However, a result of analysis showed that the Hangul Jamo Morse code was not applied in the coding theory as the english alphabet code system. This paper presents the analysis result of Hangul Jamo Morse code according to the variable length coding theory. As a result of the analysis, when Hangul Jamo are coded with application of the variable length coding theory, the transmission data rate could be increased up to 25% compare to the existing code system. This paper shows a new Hangul Jamo Morse code system based on the analysis result.