• 전기화학회지
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• 제25권4호
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• pp.125-133
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• 2022

현장 진단 검사가 가능한 센서에 대한 수요가 급증함에 따라, 이동성과 편리성이 개선된 센서에 대한 필요성이 대두되고 있다. 다양한 형태의 센서들 중에서도, 전기 변색 물질을 도입하여 분석 물질의 존재 유무 및 농도를 색 변화를 통해 나타낼 수 있는 전기 변색 센서들은 기존의 전기화학 센서 및 비색 센서의 강점들을 합친 형태의 센서로 각광받고 있다. 전기 변색 센서들은 기존 센서들에 비해 소형화 및 단순화하기 용이하며, 결과 해석이 간편하다는 장점을 지니고 있어 넓은 범위의 분석 물질들에 대해 활발히 연구되어 왔다. 더 나아가, 최근에는 전기 변색 센서를 유연한 기판 위에 형성하거나, 센서 자체에서 자가 발전이 가능하도록 발전이 이루어지고 있어 분석 물질에 대한 실시간 모니터링이 가능한 웨어러블 센서로 활용될 수 있을 것으로 기대된다. 이 리뷰에서는 다양한 형태의 전기 변색 센서들을 주요 전략 및 특징에 따라 나누어 그 원리 및 응용을 소개하였다.

• 센서학회지
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• 제31권5호
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• pp.312-317
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• 2022

Piezoelectric energy harvesting has attracted increasing attention over the last decade as a means for generating sustainable and long-lasting energy from wasted mechanical energy. To develop self-powered wearable devices, piezoelectric materials should be flexible, stretchable, and bio-eco-friendly. This study proposed the fabrication of stretchable piezoelectric composites via dispersing perovskite-structured BaTiO₃ nanoparticles inside an Ecoflex polymeric matrix. In particular, the stretchable piezoelectric sensor array was fabricated via a simple and cost-effective spin-coating process by exploiting the piezoelectric composite comprising of BaTiO₃ nanoparticles, Ecoflex matrix, and stretchable Ag coated textile electrodes. The fabricated sensor generated an output voltage of ~4.3 V under repeated compressing deformations. Moreover, the piezoelectric sensor array exhibited robust mechanical stability during mechanical pushing of ~5,000 cycles. Finite element method with multiphysics COMSOL simulation program was employed to support the experimental output performance of the fabricated device. Finally, the stretchable piezoelectric sensor array can be used as a self-powered touch sensor that can effectively detect and distinguish mechanical stimuli, such as pressing by a human finger. The fabricated sensor demonstrated potential to be used in a stretchable, lead-free, and scalable piezoelectric sensor array.

• 한국융합학회논문지
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• 제13권5호
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• pp.209-217
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• 2022

가상현실은 오큘러스로 대표되는 웨어러블 장치의 도입과 함께 새로운 국면을 맞이하였다. 이에 본 연구에서는 영어학습을 위해 1인칭 시점으로 가상현실에 직접 몰입을 가능하게 하는 오큘러스 리프트(Oculus Rift) 기반의 몰입형 가상현실을 제안한다. 학습자 시점 기반의 몰입형 가상현실에 대한 전반적이고 통합적인 고찰을 통해, 언어학습을 위한 교수설계 시 고려할 사항을 제공하는 것은 의미 있는 일이다. 따라서 본 연구는 몰입형 가상현실의 언어교육 적용의 극대화 방안을 모색하는 것을 목적으로 한다. 이러한 연구 목적을 위하여 그간의 몰입형 가상현실의 교육적 활용 사례들을 살펴보았다. 그리고 몰입형 가상현실 기반 영어학습을 위한 설계 요소의 적용을 목적으로 학습이론의 설정, 학습의 차이 고려, 학습과제 선정, 교사의 영향력 규정, 적용 감각의 종류 결정, 설계의 융통성, 사용환경을 제안하였다. 그 결과들을 통합하여 교수설계에 대한 다양한 논의와 방향성을 제시하였다.

• 대한통합의학회지
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• 제10권3호
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• pp.185-198
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• 2022

Purpose : We conducted a study to propose comparing subjective sleeping states data that was collected through scientifically measuring by using smartwatch and surveys for seafarers. In addition, we conducted a study to provide sleep though analysis of the environmental factors that influence the sleep efficiency of seafarers. Methods : For scientific measurement of seafarers' sleeping states, we measured the sleep hours and sleep efficiency for at least 3 days by using the healthcare function of smartwatches which are wearable devices. As for subjective sleeping states, we collected data on sleep hours and satisfaction rates on the quality of sleep through a survey. Lastly, as for the environmental factors that affect the sleep efficiency which is measured by smartwatches such as physical environment, bedroom space, bedroom furniture, bedding, a survey by self-evaluation method was conducted. Results : There were significant differences in the scientific sleep hours measurement values for all seafarers and the average sleep hours in the subjective survey. There were significant differences in the scientific sleep efficiency measurements of all the seafarers and the sleep satisfaction of the subjective survey, and there was no correlation between the scientific sleep efficiency and the subjective sleep satisfaction of all the seafarers. Among the environmental factors affecting the sleep efficiency of the seafarers, humidity variable had the most influence, and vibration and illuminance variables were also shown to have a very significant effect. Conclusion : We propose the measuring method that can analyze the quantitative and qualitative sleep states of the seafarers by using small activity recorders. In addition, it is very important to control humidity, vibration, and illuminance among ship environmental factors, and comfort, noise and bedroom size should also be reflected.

• 한국전문물리치료학회지
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• 제30권2호
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• pp.102-109
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• 2023

Background: While efforts have been made to differentiate fall risk in older adults using wearable devices and clinical methodologies, technologies are still infancy. We applied a decision tree (DT) algorithm using inertial measurement unit (IMU) sensor data and clinical measurements to generate high performance classification models of fall risk of older adults. Objects: This study aims to develop a classification model of fall risk using IMU data and clinical measurements in older adults. Methods: Twenty-six older adults were assessed and categorized into high and low fall risk groups. IMU sensor data were obtained while walking from each group, and features were extracted to be used for a DT algorithm with the Gini index (DT1) and the Entropy index (DT2), which generated classification models to differentiate high and low fall risk groups. Model's performance was compared and presented with accuracy, sensitivity, and specificity. Results: Accuracy, sensitivity and specificity were 77.8%, 80.0%, and 66.7%, respectively, for DT1; and 72.2%, 91.7%, and 33.3%, respectively, for DT2. Conclusion: Our results suggest that the fall risk classification using IMU sensor data obtained during gait has potentials to be developed for practical use. Different machine learning techniques involving larger data set should be warranted for future research and development.

• 예술인문사회 융합 멀티미디어 논문지
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• 제7권10호
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• pp.865-878
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• 2017

인간의 건강한 삶을 실현하기 위하여, 정신적, 육체적, 환경적 요인이 지속적이고 안정적으로 관리되어야한다. 인간건강을 안정적이고 효율적으로 관리하기 위해서 21세기 보건의료분야는 ICT기술과 지속적 상호작용 및 융합이 필수적으로 요구되어왔다. 이러한 시대적 요구는 이종(heterogeneous)기술의 결합으로 융합(fusion)기술을 창출했고, 의료기술과 ICT기술의 융합을 통해서 개인맞춤형 치료환경이 조성되며, 다양한 웨어러블 디바이스 개발로 ICT융합 모바일 건강의료 서비스가 발전되고 있다. 이러한 이종기술의 결합은 ICT융합 헬스케어시스템의 복잡도(complexity)를 기하급수적으로 상승시켜서, 다양한 기술적, 제도적, 환경적, 문화적 이슈와 문제들을 발생시키고 있다. 본 연구는 ICT 헬스케어 기술에 대해 과거부터 현재까지 이어지는 발전현황을 조명하고, 주요한 국내외 헬스케어 기술 및 정책 이슈들을 발굴하고, 최종적으로 이러한 과제들을 해결하기 위한 헬스케어 로드맵과 향후 발전방향을 제안한다.

• 한국재료학회지
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• 제33권7호
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• pp.295-301
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• 2023

Thermoelectric (TE) energy harvesting, which converts available thermal resources into electrical energy, is attracting significant attention, as it facilitates wireless and self-powered electronics. Recently, as demand for portable/wearable electronic devices and sensors increases, organic-inorganic TE films with polymeric matrix are being studied to realize flexible thermoelectric energy harvesters (f-TEHs). Here, we developed flexible organic-inorganic TE films with p-type Bi_0.5Sb_1.5Te₃ powder and polymeric matrices such as poly(3,4-eethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and poly (vinylidene fluoride) (PVDF). The fabricated TE films with a PEDOT:PSS matrix and 1 wt% of multi-walled carbon nanotube (MWCNT) exhibited a power factor value of 3.96 µW·m^-1·K^-2 which is about 2.8 times higher than that of PVDF-based TE film. We also fabricated f-TEHs using both types of TE films and investigated the TE output performance. The f-TEH made of PEDOT:PSS-based TE films harvested the maximum load voltage of 3.4 mV, with a load current of 17.4 µA, and output power of 15.7 nW at a temperature difference of 25 K, whereas the f-TEH with PVDF-based TE films generated values of 0.6 mV, 3.3 µA, and 0.54 nW. This study will broaden the fields of the research on methods to improve TE efficiency and the development of flexible organic-inorganic TE films and f-TEH.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.579-586
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• 2022

Modular building is a fast-growing construction method, mainly due to its ability to drastically reduce the amount of time it takes to construct a building and produce higher-quality buildings at a more consistent rate. However, while modular construction is relatively safer than traditional construction methods, workers are still exposed to hazards that lead to injuries and fatalities, and these hazards could be controlled using emerging smart technologies. Currently, limited information is available at the intersection of modular construction, safety risk, and smart safety technologies. This paper aims to investigate what aspects of modular construction are most dangerous for its workers, highlight specific risks in its processes, and propose ways to utilize smart technologies to mitigate these safety risks. Findings from the archival analysis of accident reports in Occupational Safety and Health Administration (OSHA) Fatality and Catastrophe Investigation Summaries indicate that 114 significant injuries were reported between 2002 and 2021, of which 67 were fatalities. About 72% of fatalities occurred during the installation phase, while 57% were caused by crushing and 85% of crash-related incidents were caused by jack failure/slippage. IoT-enabled wearable sensing devices, computer vision, smart safety harness, and Augment and Virtual Reality were identified as potential solutions for mitigating identified safety risks. The present study contributes to knowledge by identifying important safety trends, critical safety risk factors and proposing practical emerging methods for controlling these risks.

• 문화기술의 융합
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• 제9권5호
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• pp.787-800
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• 2023

본 논문은 웹 3.0 시대에 도래할 메타버스 음악 플랫폼의 학술적 이해를 도모하고 생산적인 구축 방안을 모색한 연구이다. 본 연구에서는 메타버스 음악 플랫폼이 현 시점에 지니는 의미를 입체적으로 짚어보고자 디지털 음악의 발전을 웹 1.0부터 3.0까지의 플랫폼 형성과정을 중심으로 살펴본다. 전반부에서는 메타버스 음악 플랫폼이 현재 향유하는 음악문화와 단절된 것이 아니라, 1990년대부터 지금까지 진화되어온 웹 플랫폼 환경과 밀접하게 연결되어 있다는 것을 보여주고자 했다. 또한 메타버스 플랫폼의 부상을 웹 2.0의 한계를 극복하는 동시에 웹 3.0으로의 전환과 연계된 변화로 가정하고, 최근 거론되는 1. 기술적(XR기술, 웨어러블 디바이스, 생성형 AI), 2. 문화적(디지털 아바타, 팬덤), 3. 경제적(NFT) 논의들을 현재까지 발전된 메타버스 음악 플랫폼의 발전방안과 연계시켜 논의하였다. 본 연구를 통해 '메타버스 음악 플랫폼'에 대한 합의된 개념이나 공식적인 정론이 확립되지 않은 상황에서 해당 개념에 대한 이해를 증진시키고 향후 발전방안에 대한 모색에 참고가 될 수 있기를 기대한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권10호
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• pp.2627-2642
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• 2023

Parkinson's disease (PD) is a typical, chronic neurodegenerative disease involving the concentration of dopamine, which can disrupt motor activity and cause different degrees of gait disturbance relevant to PD severity in patients. As current clinical PD diagnosis is a complex, time-consuming, and challenging task that relays on physicians' subjective evaluation of visual observations, gait disturbance has been extensively explored to make automatic detection of PD diagnosis and severity rating and provides auxiliary information for physicians' decisions using gait data from various acquisition devices. Among them, wearable sensors have the advantage of flexibility since they do not limit the wearers' activity sphere in this application scenario. In this paper, an attention-based temporal network (ATN) is designed for the time series structure of gait data (vertical ground reaction force signals) from foot sensor systems, to learn the discriminative differences related to PD severity levels hidden in sequential data. The structure of the proposed method is illuminated by Transformer Network for its success in excavating temporal information, containing three modules: a preprocessing module to map intra-moment features, a feature extractor computing complicated gait characteristic of the whole signal sequence in the temporal dimension, and a classifier for the final decision-making about PD severity assessment. The experiment is conducted on the public dataset PDgait of VGRF signals to verify the proposed model's validity and show promising classification performance compared with several existing methods.