• 센서학회지
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• 제31권3호
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• pp.156-162
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• 2022

This study estimates the relative position between body segments using segment orientation and segment-to-joint center (S2J) vectors. In many wearable motion tracking technologies, the S2J vector is treated as a constant based on the assumption that rigid body segments are connected by a mechanical ball joint. However, human body segments are deformable non-rigid bodies, and they are connected via ligaments and tendons; therefore, the S2J vector should be determined as a time-varying vector, instead of a constant. In this regard, our previous study (2021) proposed a method for determining the time-varying S2J vector from the learning dataset using a regression method. Because that method uses a deformation-related variable to consider the deformation of S2J vectors, the optimal variable must be determined in terms of estimation accuracy by motion and segment. In this study, we investigated the effects of deformation-related variables on the estimation accuracy of the relative position. The experimental results showed that the estimation accuracy was the highest when the flexion and adduction angles of the shoulder and the flexion angles of the shoulder and elbow were selected as deformation-related variables for the sternum-to-upper arm and upper arm-to-forearm, respectively. Furthermore, the case with multiple deformation-related variables was superior by an average of 2.19 mm compared to the case with a single variable.

• 스마트미디어저널
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• 제13권4호
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• pp.57-64
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• 2024

패션 이미지에 포함된 소재, 색상, 핏 등의 속성은 소비자가 의류를 구매하는 데 있어서 중요한 요인이다. 그러나 의류 속성을 분류하는 과정은 많은 인력을 필요로 하고, 작업자의 주관적인 판단에 의존하기 때문에 일관성이 떨어진다. 이러한 문제를 완화하기 위해 인공지능을 활용하여 패션 이미지의 의류 속성을 분류하는 연구가 필요하다. 기존 연구에서는 주로 상의 또는 하의 중 하나의 항목에 대한 의류 속성을 분류하는 것에 초점을 두고 있기 때문에 전신 패션 이미지의 경우에는 상의와 하의의 속성을 동시에 파악할 수 없다는 한계가 있었다. 본 연구는 패션 이미지의 상의와 하의를 구분하여 각 항목의 카테고리와 의류 소재의 속성을 분류할 수 있는 딥러닝 모델을 제안한다. 본 연구에서 딥러닝 모델 ResNet과 EfficientNet를 이용하였고, 학습에 활용한 데이터셋은 패션 이미지 1,002,718장과 의류 카테고리와 소재 속성을 포함한 라벨 총 125개를 사용하였다. Weighted F1-Score를 기준으로 ResNet은 0.800, EfficientNet는 0.781로 ResNet이 더 우수한 성능을 보였다.

• 대한치매학회지
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• 제23권3호
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• pp.146-160
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• 2024

Background and Purpose: The emotions of people at various stages of dementia need to be effectively utilized for prevention, early intervention, and care planning. With technology available for understanding and addressing the emotional needs of people, this study aims to develop speech emotion recognition (SER) technology to classify emotions for people at high risk of dementia. Methods: Speech samples from people at high risk of dementia were categorized into distinct emotions via human auditory assessment, the outcomes of which were annotated for guided deep-learning method. The architecture incorporated convolutional neural network, long short-term memory, attention layers, and Wav2Vec2, a novel feature extractor to develop automated speech-emotion recognition. Results: Twenty-seven kinds of Emotions were found in the speech of the participants. These emotions were grouped into 6 detailed emotions: happiness, interest, sadness, frustration, anger, and neutrality, and further into 3 basic emotions: positive, negative, and neutral. To improve algorithmic performance, multiple learning approaches were applied using different data sources-voice and text-and varying the number of emotions. Ultimately, a 2-stage algorithm-initial text-based classification followed by voice-based analysis-achieved the highest accuracy, reaching 70%. Conclusions: The diverse emotions identified in this study were attributed to the characteristics of the participants and the method of data collection. The speech of people at high risk of dementia to companion robots also explains the relatively low performance of the SER algorithm. Accordingly, this study suggests the systematic and comprehensive construction of a dataset from people with dementia.

• 한국기후변화학회지
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• 제34권8호
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• pp.3103-3127
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• 2021

Wind gusts represent one of the main natural hazards due to their increasing socioeconomic and environmental impacts on, for example, human safety, maritime-terrestrial-aviation activities, engineering and insurance applications, and energy production. However, the existing scientific studies focused on observed wind gusts are relatively few compared to those on mean wind speed. In Australia, previous studies found a slowdown of near-surface mean wind speed, termed "stilling," but a lack of knowledge on the multidecadal variability and trends in the magnitude (wind speed maxima) and frequency (exceeding the 90th percentile) of wind gusts exists. A new homogenized daily peak wind gusts (DPWG) dataset containing 548 time series across Australia for 1941-2016 is analyzed to determine long-term trends in wind gusts. Here we show that both the magnitude and frequency of DPWG declined across much of the continent, with a distinct seasonality: negative trends in summer-pring-autumn and weak negative or nontrending (even positive) trends in winter. We demonstrate that ocean-atmosphere oscillations such as the Indian Ocean dipole and the southern annular mode partly modulate decadal-scale variations of DPWG. The long-term declining trend of DPWG is consistent with the "stilling" phenomenon, suggesting that global warming may have reduced Australian wind gusts.

• Journal of Radiation Protection and Research
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• 제44권4호
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• pp.128-148
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• 2019

Massive environmental monitoring has been conducted continuously since the Fukushima Daiichi Nuclear Power accident in March of 2011 by different monitoring methods that have different features together with migration studies of radiocesium in diverse environments. These results have clarified the characteristics of radiological environments and their temporal change around the Fukushima site. At three months after the accident, multiple radionuclides including radiostrontium and plutonium were detected in many locations; and it was confirmed that radiocesium was most important from the viewpoint of long-term exposure. Radiation levels around the Fukushima site have decreased greatly over time. The decreasing trend was found to change variously according to local conditions. The air dose rates in environments related to human living have decreased faster than expected from radioactive decay by a factor of 2-3 on average; those in pure forest have decreased more closely to physical decay. The main causes of air dose rate reduction were judged to be radioactive decay, movement of radiocesium in vertical and horizontal directions, and decontamination. Land-use categories and human activities have significantly affected the reduction tendency. Difference in the air dose rate reduction trends can be explained qualitatively according to the knowledge obtained in radiocesium migration studies; whereas, the quantitative explanation for individual sites is an important future challenge. The ecological half-lives of air dose rates have been evaluated by several researchers, and a short-term half-life within 1 year was commonly observed in the studies. An empirical model for predicting air dose rate distribution was developed based on statistical analysis of an extensive car-borne survey dataset, which enabled the prediction with confidence intervals. Different types of contamination maps were integrated to better quantify the spatial data. The obtained data were used for extended studies such as for identifying the main reactor that caused the contamination of arbitrary regions and developing standard procedures for environmental measurement and sampling. Annual external exposure doses for residents who intended to return to their homes were estimated as within a few millisieverts. Different forms of environmental data and knowledge have been provided for wide spectrum of people. Diverse aspects of lessons learned from the Fukushima accident, including practical ones, must be passed on to future generations.

• 한국경제지리학회지
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• 제23권1호
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• pp.1-17
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• 2020

본 연구는 기업 간 거래망을 활용하여 지역 간 경제적 연계를 확인하고 경제적 상호의존성에 기초한 기능적 경제권을 설정하는데 그 목적이 있다. 기존의 경제권은 이미 알려진 행정도 경계나 문화적 동질성을 기준으로만 설정되거나 실증자료를 활용하더라도 통근, 인구이동, 화물흐름 등 경제활동을 충분히 설명하지 못하는 자료에만 의존하였다. 본 연구는 이러한 한계를 극복하기 위해 한국기업데이터의 CRETOP+ 데이터베이스를 활용하여 실제 기업 간 거래망을 구축하고, 커뮤니티 발견법을 적용해 우리나라의 기능적 경제권을 파악하였다. 분석결과 거래망에 따라 6~7개의 경제권이 도출되었다. 특히 수도권, 충청권, 강원권을 통합한 하나의 거대한 경제권역이 형성되어 있었으며, 전북, 전남은 서로 간의 기업 간 거래빈도가 매우 낮아 호남권으로 묶이기보다 별도의 경제권을 형성하고 있는 것으로 나타났다. 대구, 경북의 경제권과 부산, 경남의 경제권이 각각 존재하는 것으로 나타났지만 울산, 경주, 포항은 도 경계를 넘어서 별도의 권역을 형성하고 있는 것으로 나타났다. 이를 통해 본 연구는 향후 국가균형발전정책에서 실증 자료에 기반한 정책공간의 설정이 필요함을 주장한다.

• 한국환경보건학회지
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• 제49권2호
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• pp.89-98
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• 2023

Background: Organophosphorus flame retardants (OPFRs) are a group of chemical substances used in building materials and plastic products to suppress or mitigate the combustion of materials. Although OPFRs are generally used in mixed form, information on their mixture toxicity is quite scarce. Objectives: This study aims to elucidate the toxicity and determine the types of interaction (e.g., synergistic, additive, and antagonistic effect) of OPFRs mixtures. Methods: Nine organophosphorus flame retardants, including TEHP (tris(2-ethylhexyl) phosphate) and TDCPP (tris(1,3-dichloro-2-propyl) phosphate), were selected based on indoor dust measurement data in South Korea. Nine OPFRs were exposed to the luminescent bacteria Aliivibrio fischeri for 30 minutes and the human hepatocyte cell line HepG2 for 48 hours. Chemicals with significant toxicity were only used for mixture toxicity tests in HepG2. In addition, the observed EC_x values were compared with the predicted toxicity values in the CA (concentration addition) prediction model, and the MDR (model deviation ratio) was calculated to determine the type of interaction. Results: Only four chemicals showed significant toxicity in the luminescent bacteria assays. However, EC₅₀ values were derived for seven out of nine OPFRs in the HepG2 assays. In the HepG2 assays, the highest to lowest EC₅₀ were in the order of the molecular weight of the target chemicals. In the further mixture tests, most binary mixtures show additive interactions except for the two combinations that have TPhP (triphenyl phosphate), i.e., TPhP and TDCPP, and TPhP and TBOEP (tris(2-butoxyethyl) phosphate). Conclusions: Our data shows OPFR mixtures usually have additivity; however, more research is needed to find out the reason for the synergistic effect of TPhP. Also, the mixture experimental dataset can be used as a training and validation set for developing the mixture toxicity prediction model as a further step.

• 아태비즈니스연구
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• 제14권4호
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• pp.67-85
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• 2023

Purpose - This study seeks to investigate the determinants of global sourcing intention in clothing sewing industry, in particular with its focus on women's knit wear production. Design/methodology/approach - This study collected a unique set of qualitative data through 31 in-depth interviews with fashion brands, promotion agencies, and sewing factories between July 2023 and October 2023. In addition, it analyzed the dataset using the MAXQDA to complement the research findings. Findings - We have two findings. First, the interviewees commonly mentioned the following factors as reasons for considering global sourcing: the human factors(aging of skilled technicians and labor shortages), the financial factors(gap in production unit prices at home and abroad), the relational factors(lack of novelty), and the physical factors(loss of production infrastructure and network), while the human factors(skilled workforce), the production factors(delivery date and product quality), and the relational factors(timely communication and mutual trust) as reasons for continuing domestic sourcing. Additional code analysis of interview also supports this finding. On the other hand, there was also a subtle difference between buyers(brands) and suppliers(promotion agencies and processing plants), and buyers consider the exact delivery date critical so that they could see trend-sensitive women's knit wear on time, and suppliers took production costs, labor costs, and labor shortages, which are financial factors, more seriously. Research implications or Originality - This study provides a richer and more balanced view of existing literature, which has generally tended to introduce global sourcing across the clothing industry despite the existence of various diversity within the industry. In addition, through qualitative research, we introduce that the sewing industry is carried out according to complex factors, and by revealing and categorizing the determinants of global sourcing, we supplement the existing research on the clothing sewing industry centered on survey. On a practical note, this study introduces that there is a difference in view of domestic sourcing and global sourcing between buyers(brands) and suppliers(promotion agencies and sewing factories), suggesting practical implications for revitalizing networks and deriving win-win cooperation network models among members in the future.

• International Journal of Stem Cells
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• 제15권3호
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• pp.324-333
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• 2022

Background and Objectives: This study was to investigate the role of microRNA-29a-3p (miR-29a-3p) in human bone marrow mesenchymal stem cells (hBMSCs), and its relationship with steroid-associated osteonecrosis. Methods and Results: The online tool GEO2R was used to screen out the differentially expressed genes (DEGs) in GSE123568 dataset. Quantitative real time-polymerase chain reaction (qRT-PCR) was performed to detect the expression of miR-29a-3p, forkhead box O3 (FOXO3), alkaline phosphatase (ALP), bone gamma-carboxyglutamate protein (OCN) and RUNX family transcription factor 2 (Runx2) in the hBMSCs isolated from the patients with steroid-associated osteonecrosis. CCK-8 assay was executed to measure cell viability; western blot assay was utilized to detect FOXO3, ALP, Runx2, OCN and β-catenin expression. Cell apoptosis and cell cycle were detected by flow cytometry. Immunofluorescence assay was used to detect the sub-cellular localization of β-catenin. Bioinformatics analysis and luciferase reporter gene assay were performed to confirm whether miR-29a-3p can combine with FOXO3 3'UTR. MiR-29a-3p was markedly up-regulated in the hBMSCs of patients with steroid-associated osteonecrosis, while FOXO3 mRNA was significantly down-regulated. Transfection of miR-29a-3p mimics significantly inhibited the hBMSCs' proliferation, osteogenic differentiation markers' expressions, including ALP, Runx2, OCN, and repressed the ALP activity, as well as promoted cell apoptosis and cell-cycle arrest. FOXO3 was identified as a target gene of miR-29a-3p, and miR-29a-3p can inhibit the expression of FOXO3 and β-catenin, and inhibition of miR-29a-3p promoted translocation of β-catenin to the nucleus. Conclusions: MiR-29a-3p can modulate FOXO3 expression and Wnt/β-catenin signaling to inhibit viability and osteogenic differentiation of hBMSCs, thereby promoting the development of steroid-associated osteonecrosis.

• 한국지능시스템학회논문지
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• 제24권5호
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• pp.518-528
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• 2014

본 논문에서는 4차원 시공간 (4D-ST, [x,y,z,t]) 특징을 이용하여 행동 방향을 인식하는 방법을 제안한다. 이를 위해 4차원 시공간 특징점 (4D-STIPs, [x,y,z,t])을 제안하였고, 이는 여러 다른 뷰에서 촬영한 이미지들로부터 복원된 3차원 공간 (3D-S, [x,y,z]) 볼륨으로부터 계산된다. 3차원 공간정보를 갖고 있는 3D-S 볼륨과 4D-STIPs는 2차원 공간 (2D-S, [x,y]) 뷰로 사영을 하여 임의의 2D-S 뷰에서의 특징을 생성해 낼 수 있다. 이 때, 사영 방향을 결정 할 수 있으므로, 학습 시 방향에 대한 정보를 포함하여 행동 방향을 인식 할 수 있다. 행동 방향을 인식하는 과정은 두 단계로 나눌 수 있는데, 우선 어떤 행동인지를 인식하고 그 후, 방향 정보를 이용하여 최종적으로 행동 방향을 인식한다. 행동 인식과 방향 인식을 위해, 사영된 3D-S 볼륨과 4D-STIPs은 각각 움직이는 부분과 움직이지 않는 부분에 대한 정보를 담고 있는 motion history images (MHIs)와 non-motion history images (NMHIs)로 구성된다. 이러한 특징들은 행동 인식을 위해, 방향 정보에 상관없이 같은 행동이면 같은 클래스로 분류되어 support vector data description (SVDD) 분류기로 학습되고, support vector domain density description (SVDDD)을 이용하여 인식된다. 인식된 행동에서 최종적으로 방향을 인식하기 위해 각 행동을 방향 클래스로 분류하여 SVDD 분류기로 학습하고 SVDDD로 인식한다. 제안된 방법의 성능을 보이기 위해서 INRIA Xmas Motion Acquisition Sequences (IXMAS) 데이터셋에서 제공하는 3D-S 볼륨을 사용하여 학습을 하고, 행동 방향 인식 실험이 가능한 SNU 데이터셋을 구축하여 인식 실험을 하였다.