• The Journal of the Acoustical Society of Korea
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• v.22 no.6
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• pp.452-456
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• 2003

We discuss how to reduce the number of inverse matrix and its dimensions requested in MLLR framework for speaker adaptation. To find a smaller set of variables with less redundancy, we adapt PCA (principal component analysis) and ICA (independent component analysis) that would give as good a representation as possible. The amount of additional computation when PCA or ICA is applied is as small as it can be disregarded. 10 components for ICA and 12 components for PCA represent similar performance with 36 components for ordinary MLLR framework. If dimension of SI model parameter is n, the amount of computation of inverse matrix in MLLR is proportioned to O(n⁴). So, compared with ordinary MLLR, the amount of total computation requested in speaker adaptation is reduced by about 1/81 in MLLR with PCA and 1/167 in MLLR with ICA.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.604-604
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• 2013

차세대 반도체 분야인 스핀트로닉스 소자의 필수적인 물질인 강자성-반도체 하이브리드 물질인 Dilute magnetic semiconductor (DMS)에 관한 연구가 최근 많은 관심을 가지고 있다. 그중에서 넓은 에너지 밴드 갭 에너지(3.37 eV)를 가지고 있고 상온에서 엑시톤 결합 에너지가 ~60 mV로 광전자 소자, 전계 디스플레이 에 응용이 가능한 물질인 ZnO는 최근에 전이금속을 도핑하여 상온에서 강자성 특성을 나타내어 활발한 연구가 이루어지고 있다. 그러나, 이 물질에 대한 특성과 자성의 원인 규명에 관한 연구는 논란이 되고 있다. 본 연구에서는 Mn이 도핑된 ZnO 나노 입자를 만들고, Mn 물질의 도핑 농도에 따른 ZnO 나노 입자의 구조, 크기 및 자기 구조를 측정하여 구조와 자성의 상관관계에 관한 연구하였다. ZnxMn1-xO 나노 입자는 화학적 졸-겔(sol-gel) 방법을 이용하여 준비하였다. ZnxMn1-xO 나노 입자의 크기 및 격자 구조적 특징은 XRD (X-ray diffraction)와 TEM (Transmission Electron Microscope), SEM (Scanning Electron Microscope), SANS (Small Angle Neutron Scattering)를 이용하여 측정하였고 물질의 자기적 특징은 SQUID를 이용하여 조사하였다. Mn 도핑이 증가함에 따라 격자간격이 커지고 나노 입자의 크기는 감소하였으며, Zn와 Mn의 성장 시, 비율이 9:1의 경우에 상온에서 강자성 특성이 나타남을 보았다. 그 이상의 Mn 도핑 비율에서는 상자성 특성이 나타남을 보았다. 본 연구를 통하여 스핀트로닉스 소자 응용을 위한 ZnO 나노 입자에 최적의 Mn 도핑 농도를 제시하고 나노 입자의 자기 특성 형성의 원인 및 모델을 제시하였다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.6
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• pp.549-559
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• 2008

This study verified the limitations of commercial GPS data processing software and the applicability on precise positioning through comparing the processing results between Bernese and TGO under various conditions. To achieve the goal, we selected three nationwide station data and two smaller local data to constitute networks. By using Bernese and TGO, those networks are processed through the baseline analysis and the network adjustment. The comparative analysis was carried out, in terms of software, baseline length and network scale, observation duration, and number of fixed points. In the comparison between softwares, the scientific software was excellent in accuracy. It was confirmed that, as GPS-related technology is developed, the performance of the receiver was enhanced. And, in parallel with this, even the functionalities of the commercial software were tremendously enhanced. The difference, however, in result between the scientific and commercial software are still exist even if it is not big. Therefore, this study confirms that the scientific software should be used when the most precise position is necessary to be computed, especially if baseline vectors are big.

• Journal of the Korea Convergence Society
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• v.12 no.11
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• pp.301-310
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• 2021

This study is qualitative research with an aim of assessing experience of prospective social work student enrolled in social welfare field practice during COVID-19 pandemic. The results are shown below. First, the major negative answers of responders were the work-study imbalance of the student, the institution's concern for spread of infection, limited experience due to low-quality-of supervision, the difficulty on choosing institution, and worries on stop of practice due to the COVID-19 pandemic. Second, the key positive answers of responders were awareness of true meaning of social welfare, a major of them, significance of field practice, importance of human rights in their field, and finally, dearness of rapport building between social workers and clients in social welfare practice settings.

• Journal of Biomedical Engineering Research
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• v.43 no.6
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• pp.424-433
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• 2022

As the proportion of non-contact telemedicine increases and the number of electrocardiogram (ECG) data measured using portable ECG monitors increases, the demand for automatic algorithms that can precisely analyze vast amounts of ECG is increasing. Since the P, QRS, and T waves of the ECG have different shapes depending on the location of electrodes or individual characteristics and often have similar frequency components or amplitudes, it is difficult to distinguish P, QRS and T waves and measure each parameter. In order to measure the widths, intervals and areas of P, QRS, and T waves, a new algorithm that recognizes the start and end points of each wave and automatically measures the time differences and amplitudes between each point is required. In this study, the start and end points of the P, QRS, and T waves were measured using six Deep Neural Networks (DNN) that recognize the start and end points of each wave. Then, by synthesizing the results of all DNNs, 12 parameters for ECG characteristics for each heartbeat were obtained. In the ECG waveform of 10 subjects provided by Physionet, 12 parameters were measured for each of 660 heartbeats, and the 12 parameters measured for each heartbeat well represented the characteristics of the ECG, so it was possible to distinguish them from other subjects' parameters. When the ECG data of 10 subjects were combined into one file and analyzed with the suggested algorithm, 10 types of ECG waveform were observed, and two types of ECG waveform were simultaneously observed in 5 subjects, however, it was not observed that one person had more than two types.

• Journal of the Korea Convergence Society
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• v.13 no.5
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• pp.195-200
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• 2022

It was in the 1990s that the human rights of persons with disabilities began to be discussed in our society. Based on the Declaration on the Rights of Persons with Disabilities adopted by the UN General Assembly in 1975, the Charter on the Rights of Persons with Disabilities was adopted on December 8, 1988. The human rights of persons with disabilities explains the important meaning of not being discriminated against just because they are persons with disabilities, the basics of human rights that all human beings have. The human rights of persons with disabilities are universal values, a basic right, and a declaration to protect the socially disadvantaged. Human rights are an important ideology that deals with the dignity and worth of human beings. In our society, people with disabilities should not be discriminated against for any reason. Persons with disabilities should be the center in matters related to the Anti-Discrimination Act and Human Rights. In addition, it can be said that it is necessary to develop and operate a system suitable for the local government for the disabled in the local community.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.4
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• pp.464-470
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• 2023

Objectives: This study evaluated occupational exposures to noise and heat stress during routine non-outage works in three coal-fired power plants in the Republic of Korea. Methods: The data were collected during the summer of 2020. Full shift noise exposure of 52 workers were measured using noise dosimeters. Heat stress of 16 worksites were measured for 70 minutes using wet-bulb globe temperature monitors. Results: The noise dosimetry results revealed time-weighted averages that ranged from 47.5 to 88.9 dBA. 2 out of 52 noise measurements exceeded 85 dBA. Based on the arithmetic mean, the coal service group showed the highest level at 80.2 dBA by job tasks. Noise exposures exceeding 85 dBA were measured in the coal service and plant operator group. Heat stress index measurements ranged from 20.3℃ to 37.2℃. 1 out of 9 indices measured in coal facilities and 4 out of 7 indices measured in boiler house exceeded 1 hour TWA during moderate work. Heat stress indices measured from boiler houses were significantly higher than those measured from coal equipment. Conclusions: The results show that overexposure to noise and heat stress may be encountered during routine non-outage work activities in coal-fired power plants. Appropriate actions should be taken to reduce future health outcome from occupational exposure to noise and heat stress in the industry.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.728-733
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• 2009

지금까지의 하천 설계는 하천의 유량, 유사량, 하상토 입도분포, 강턱의 입자 또는 하도 표면의 특성, 하곡의 경사 등을 고려하여 안정한 횡단면을 결정하기 위한 목적으로 발전되어 왔다. 하지만, 하천 복원에 있어서 이동 하상의 안정 하도 및 하천을 설계하는 작업은 수리학적, 하천 형태학적, 그리고 유사 수리학적 측면에서 매우 복잡한 문제들을 포함하고 있으며 더 나아가 다양한 생태서식처 및 환경을 제공할 수 있는 측면까지도 고려하도록 요구되어 지고 있다. 자연하천 복원 설계시 가장 선행되어야 할 작업은 복원하고자 하는 현재의 하천 및 하도의 안정성에 대한 평가이며 이러한 과정에서 평형 하천의 개념을 반드시 고려해야 한다. 안정하도 및 평형하천 형태를 계산하는 방법들이 여러 연구자들에 의해 제안되어 왔고 여러 해석적 방법들 중 Copeland의 방법은 실제로 충적하천에서의 안정 하도 평가 및 설계에 가장 많이 이용되고 있으며 미공병단에 의해 개발된 SAM(Stable Channel Analysis Model) 모형에서 채택하고 있는 해석적 방법 중 하나이다. 본 연구에서는 Copeland의 해석적 안정하도 분석 방법을 기본 모듈로 채택하고 있는 미공병단에서 개발한 SAM(Stable Channel Analysis Model)의 기본적인 특성과 활용도에 대해서 알아보고 이를 남한강 제1지류인 청미천의 구하도 복원 예정 구간에 적용시켜 현재하도의 안정성을 평가하였다. 분석 결과, 안정하도 경사는 현재 하도 경사보다 완만한 것으로 나타났으나 SAM에서 예측하고 있는 청미천의 안정 하폭은 현재 하도의 하폭보다 훨씬 작은 것으로 나타났다. 이는 현재 청미천의 복원 구간에서 사주가 많이 발생하는 이유를 뒷받침 하는 결과라고 할 수 있다. 안정수심은 현재 하도의 수심보다 깊은 것으로 계산되었다. SAM을 이용한 계산 결과들은 현재하도의 안정성 평가뿐만 아니라 복원 구간의 안정하도 설계를 위한 기초자료로 활용될 것이다.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.2
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• pp.146-151
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• 2016

In patients with fully edentulous maxilla, fabrication of implant-supported overdenture can be a viable treatment option, when a minimum of six implants were strategically placed. Among several attachment systems used for implant-supported overdentures, milled-bars prevent rotational movement of denture, thus showing great stability, and have the advantage of splinting multiple implants with each other. In this case report, a milled-bar supported overdenture was fabricated for a patient suffering from condition of fully edentulous maxilla with severe ridge resorption in the anterior residual ridge. Seven implants composed of three different systems were effectively utilized by CAD/CAM customized abutment and cement-retained milled bar.

• Journal of Korea Water Resources Association
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• v.46 no.12
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• pp.1209-1220
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• 2013

Roughness coefficients calibrated by flow modeling using the 1-dimensional numerical model were analyzed for the downstream section of Naesung Stream in this study. Also, the bedform configuration at the Hyangseok Station was predicted for measured and simulated hydraulic conditions of flows and total flow roughness was estimated with the coefficient of grain roughness. The Manning's n coefficients calibrated by numerical modeling and estimated by considering of grain and bedform roughness were compared and examined. As a result, the Manning's n by numerical modeling was greater than the coefficient range estimated by grain and bedform roughness at the low flow regime due to the other factors such as vegetation, sinuosity, and sand bar. However, the Manning's n by numerical modeling was included in the coefficient range by grain and bedform roughness at the transition and high flow regime over $500m^3/s$ of flow discharge.