가속도 센서를 이용한 보행속도 측정과 정확도 분석

Euntae Bae,Joonseok Park 한국차세대컴퓨팅학회 2021 한국차세대컴퓨팅학회 학술대회 Vol.2021 No.05

고령인구의 증가가 사회적 문제로 부상하면서 고령자 상황인지 및 응급상황 대응 기술에 대한 수요가 증가하고 있다. 낙상은 고령자의 일상생활에서 빈번히 발생하는 동시에 고령자의 건강과 삶의 질을 위협하는 중대한 위험요인이므로 이에 대한 대비가 중요하다. 보폭 및 보행 속도 측정과 같은 보행 분석은 낙상 가능성을 감지하는 데 중요한 인자로 알려져 있다. 본 연구에서는 저가의 가속도 센서만을 이용하여 보행속도를 측정하는 방법을 제안한다. 실험을 통해 측정 데이터와 실제 보행속도에 따른 오차 경향을 분석함으로써 일상 생활 중 보행 분석이 가능함을 확인하였다.

Dose Evaluation of the Man Adjacent to an Implanted Patient During the Prostate Cancer Brachytherapy

Euntae Park(박은태),Junghoon Kim(김정훈) 한국방사선학회 2016 한국방사선학회 논문지 Vol.10 No.1

본 연구는 전립선암의 치료방법 중 근접치료 시 환자 주변의 공간에 대한 선량을 평가한 것으로 환자, 시술자 그리고 보호자에 대한 선량을 예측함으로서 피폭을 최소한으로 예방하고자 수행하였다. 실험방법 은 몬테칼로법을 기반으로 한 MCNPX를 사용하여 가상의 공간에서 모의피폭체를 만들어 실험하였으며, 선원은 192 Ir, 125 I, 103 Pd를 seed 형태로 이식하였다. 환자를 중심으로 전방 30, 50, 100, 200 ㎝ 거리에 관심영역을 설정하여 공간 선량을 평가하였다. 그 결과 거리에 관계없이 192 Ir에서 가장 높은 선량을 나타내었다. This study is fulfilled to evaluate the exposure dose nearby a patient during the brachytherapy of the prostate cancer treatment and to minimize the radiation exposure by evaluating the exposure dose of the person near the relevant implanted patient, technicians and gardians. The experiment method is used on the study is MCNPX that is stood on the basis monte-carlo method and implant the source to MIRD-type phantom in 192 Ir, 125 I, and 103 Pd in virtual space. For dose evaluations according to distance, the radiation dose on the patient near the corresponding implanted patient is evaluated by each distance of 30, 50, 100, 200 cm to anterior from the implanted patient. As a result, 192 Ir showed a higher dose than 125 I and 103 Pd in every distance.

Asymmetric mixed-matrix membranes incorporated with nitrogen-doped graphene nanosheets for highly selective gas separation

Euntae Yang,Kunli Goh,Chong Yang Chuah,Rong Wang,Tae-Hyun Bae 한국막학회 2020 한국막학회 총회 및 학술발표회 Vol.2020 No.11

Improvement of biohydrogen generation and seawater desalination in a microbial electrodialysis cell by installing the direct proton transfer pathway between the anode and cathode chambers

Yang, Euntae,Choi, Mi-Jin,Kim, Kyoung-Yeol,Kim, In S. Taylor Francis 2013 Desalination and water treatment Vol.51 No.31

Laminar reduced graphene oxide membrane modified with silver nanoparticle-polydopamine for water/ion separation and biofouling resistance enhancement

Yang, Euntae,Alayande, Abayomi Babatunde,Kim, Chang-Min,Song, Jun-ho,Kim, In S. Elsevier 2018 Desalination Vol.426 No.-

<P><B>Abstract</B></P> <P>Laminar graphene oxide (GO) membranes with excellent water permeability have demonstrated great potential in the field of membrane-based water purification. However, low ion rejection and controversy over their biofouling propensity are hurdles GO membranes face in realizing commercial applications. This study shows that silver nanoparticle (nAg)@polydopamine (pDA) deposition on chemically reduced GO (rGO) laminates can simultaneously enhance both biofouling resistance and ion rejection. In pressurized filtration tests, the salt rejection of nAg@pDA-rGO membranes outperformed that of GO membranes despite its lowered water permeability. In osmotic filtration tests, nAg@pDA-rGO membranes achieved an increased water flux of 28.9LMH and reduced reverse solute flux of 0.21mol/m<SUP>2</SUP>·h, compared to GO membranes. Moreover, extremely low cell attachment and viability were seen on the nAg@pDA-rGO membrane, confirming the excellent antibiofouling ability of nAg-pDA-rGO membranes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fouling resistance and ion selectivity of GO membranes were improved. </LI> <LI> Enhanced ion selectivity by reduction of laminar GO layer. </LI> <LI> Increased fouling resistance by coating silver nanoparticle-polydopamine layer. </LI> <LI> Performance of GO membranes were assessed under hydraulic and osmotic pressure. </LI> <LI> Fouling resistance of GO membranes were evaluated. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Enhanced desalination performance of forward osmosis membranes based on reduced graphene oxide laminates coated with hydrophilic polydopamine

Yang, Euntae,Kim, Chang-Min,Song, Jun-ho,Ki, Hangil,Ham, Moon-Ho,Kim, In S. Elsevier 2017 Carbon Vol.117 No.-

<P>Forward osmosis (FO) processes have been recognized as a low energy required next-generation desalination technology, but the low performance of polymeric membranes remains a bottleneck in the practical application of FO. Graphene oxide (GO) membranes possess a huge potential as an alternative to polymeric membranes because of their facile fabrication procedure, ultra-thin thickness, controllable pore size, and outperformance of competing materials in terms of water transport rate; the low stability of GO laminates under water and their hydrophobic property (if GO laminates are reduced) remain as problems requiring solution prior to their practical implementation. To solve these problems, herein, the chemical reduction of GO laminates and a hydrophilic adhesive polydopamine (pDA) layer were applied. Reduced GO (rGO) laminates sustainably retained their compacted nanochannels (3.45 A) compared to pristine GO laminates, which increased the selectivity of hydrated ions. In addition, adding a pDA coating onto the rGO laminates improved the hydrophilicity of the rGO laminate surface, which accelerated the water absorption speed. As a result of these synergistic effects, pDA-coated rGO (pDA-rGO) membranes achieved an outstanding water flux of 36.6 L/m(2). h, with a reverse solute flux of 0.042 mol/m(2).h and a high salt rejection rate of 92.0% in FO. (C) 2017 Elsevier Ltd. All rights reserved.</P>

방사선치료실 내의 광중성자 에너지 분포 평가

박은태(Euntae Park),고성진(Seongjin Ko),김정훈(Junghoon Kim),강세식(Sesik Kang) 대한방사선과학회(구 대한방사선기술학회) 2014 방사선기술과학 Vol.37 No.3

의료용의 선형가속장치는 방사선치료에 있어서 그 활용도가 가장 높으며, 최근에는 10MV 이상의 고에너지 광자선을 이용한 치료가 보편화되고 있다. 그러나 광핵반응에 의한 광중성자가 생성됨으로써 방사선 방호 측면에서 많은 문제를 야기 시키고 있다. 이에 본 연구는 MCNPX 프로그램을 이용하여 치료실 내의 위치별 중성자의 특성을 분석하였다. 그 결과, 광중성자의 생성 개수도 선원 중심점을 기준으로 거리가 멀어질수록 감소됨을 알 수 있었다. 그리고 10MV에서 20MV로 에너지가 높아짐에 따른 열중성자와 속중성자의 비율은 큰 차이가 없었지만, 선원 중심점으로부터 거리가 이격될수록 열중성자의 비율이 높아지는 현상을 확인할 수 있었다. Medical linear accelerator is widely used in radiation treatment field, and high energy photons, above 10 MV nominal accelerator voltage, are commonly utilized for the radiation treatment. However, these high energy photons lead the photo-nuclear reaction and the generation of photo-neutrons are accompanied. Thus, these problematic factors are issued in the view of radiation protection. Therefore, linear accelerator and radiation treatment room are simulated from MCNPX program in this study. The measurement points of interest are selected and analyzed, and the resulting effects derived from the properties of photo-neu-tron are evaluated. Therefore, we realized that the number of generating photo-neutrons was decreased by depending on the distance from the source. No matter what the nominal energy is set, the rates thermal neutrons to fast neutrons are marginal. It is founded that the amount of the thermal neutrons were de-creased by depending on the distance from the source.

Tunable semi-permeability of graphene-based membranes by adjusting reduction degree of laminar graphene oxide layer

Yang, Euntae,Ham, Moon-Ho,Park, Ho Bum,Kim, Chang-Min,Song, Jun-ho,Kim, In S. Elsevier 2018 Journal of membrane science Vol.547 No.-

<P><B>Abstract</B></P> <P>Membrane-based water reuse and desalination technologies have been increasingly popular as an alternative water resource for mitigating global water scarcity. However, intrinsic limitations of conventional membranes restrict a further advance in membrane-based technologies. Recently, laminar-structure graphene oxide (GO) membranes fabricated by staking GO nanoplatelets have been emerging as a new water purification membrane with overcoming the conventional membrane limitations because of ultra-fast water permeation and precise molecular sieving capability based on ultra-low friction and well-defined nanochannels; to apply laminar GO membranes for ion removal such as desalination, tuning size of GO nanochannels within a sub-nanometer range is required. Herein, we adjusted reduction degree of GO laminates via varying exposure time to hydroiodic acid steam to control the size of GO nanochannels in a sub-nanometer range. Control of the hydroiodic acid vapor exposure time is a facile way to tune the nanochannel size in a sub-nanometer, and consequentially monovalent ion rejection rate can be handled.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Graphene oxide (GO) laminates was exposed to hydroiodic acid (HI) vapor for reduction. </LI> <LI> Exposure time to HI vapor was controlled to adjust degree of reduction of GO laminates. </LI> <LI> With increasing degree of reduction of GO layer, the GO nanochannel size was decreased. </LI> <LI> Water/ion semipermeability can be controlled by manipulating degree of reduction of GO layer. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

경상남도 물산업 현황 및 발전 방안

양은태(Euntae Yang),김향미(Hyang-Mi Kim),지호빈(Ho Bin Jee),송승현(Seung Hyun Song),최창규(Changkyoo Choi) 대한환경공학회 2021 대한환경공학회지 Vol.43 No.4

목적 : 경상남도의 물산업 현황과 발전 방안을 살펴보고자 한다. 방법 : 전세계 물산업과 경상남도의 지역 물산업 현황을 통계자료 및 데이터베이스의 활용, 기업을 대상으로 한 설문조사 등을 통하여 파악하였다. 그리고 이를 통해 파악된 현황과 경상남도의 산업 기반 및 지역적 특성 등이 고려된 지역 물산업 발전 전략을 살펴보았다. 결과 및 토의 : 세계 물시장은 지난 몇십 년 간 지속적으로 성장해 왔지만, 최근 코로나 대유행으로 인해 성장세가 다소 둔화될 것으로 전망되었다. 그러나 하수 내 바이러스 모니터링 등 새로운 분야에 대한 투자를 촉진시킨 측면도 있다. 국내 물산업의 경우 인프라는 잘 갖추어졌지만, 단순한 시설투자에 의한 매출 발생 구조, 물기업의 영세성과 기술력 부족 등의 문제점이 있는 것으로 드러났다. 경상남도 지역 물산업의 경우, 인프라와 관련된 상하수도 보급률은 도서산간지역이 많은 이유로 전국평균보다 낮지만, 물산업 관련 기업 수는 약 1300여개가 있는 것으로 파악되어 타시도와 비교해 많은 편으로 나타났다. 업종별로는 밸브 및 펌프 같은 물산업 관련 부품을 생산하는 제조업이 60% 이상을 차지하였다. 규모에 따른 분포에서는 ‘종업원 9인 이하’의 기업이 60% 이상을 차지하는 것으로 나타났다. 약 86% 이상의 기업이 연구개발 활동을 하지 않는 것으로 파악되었다. 이는 많은 기업이 자금 부담 및 전문 인력 부족으로 인해 기업 자체적으로는 기술 개발 및 시장 개척에 어려움을 겪고 있는 현실을 보여준다. 이러한 현실을 극복하고 지역 물산업을 발전시키기 위해서는 지방정부를 중심으로 한 물산업 육성 환경조성, 기업지원 체계 마련, 국내외 네트워크 강화 및 협력체계 구축, 지리적 특성과 산업적 장점을 활용한 물산업 육성, 추가 수요 발굴을 통한 내수시장 규모 확대 등의 전략이 필요하다. 결론 : 경상남도 지역 물산업 육성을 위해 해결해야하는 여러 문제점이 있다. 그러나 최근 정부가 본격적으로 물산업 발전을 위해 노력을 하고 있다. 따라서 경상남도도 지역 물산업의 육성을 위해 실효성 있는 발전 전략 및 정책을 수립하고 실천하는 것이 필요하다. Objectives : The status of the future development direction of the water industry in Gyeongsangnam-do Province have been explored. Methods : The status of the global and domestic water industry and the local water industry in Gyeongsangnamdo was examined through a simple survey analysis and the utilization of related-statistical data and databases. Also, the water industry development strategies of Gyeongsangnam-do were investigated by considering the status and the regional and industrial-based characteristics of Gyeongsangnam-do. Results and Discussion : The global water industry and markets have constantly been grown. The growth of the global water market was forecasted to slow down a bit due to the recent COVID-19 epidemic. On the other hand, it has promoted investment in new areas such as monitoring viruses in sewage. Although the infrastructure of the domestic water industry is well established, there are several problems such as profit structure by simple facility investment, and the poor financial condition and the lack of technical skills of the water industry-related companies. The supply rate of water and sewage in Gyeongsangnam-do was shown lower than the national average due to many islands and mountainous areas. The number of water industry-related companies was found to be about 1300 and Gyeongsangnam-do has quite a large number of water industry-related companies compared to other provinces. By sector, manufacturing industries that produce water-related components such as valves and pumps accounted for more than 60%. By scale based on the number of employees showed that “less than nine” accounted for more than 60%. More than 86% out of the total number of local water-industry companies did not conduct research and development activities. Many companies suffer from difficulties to develop technologies and pioneer new markets owing to the financial burden and lack of professional manpower. To overcome these difficulties and promote the local water industry, strategies such as creating an environment for water industry promotion, establishing a corporate support system, strengthening domestic and foreign networks, and expanding the scale of the domestic market by creating a new water business and finding additional demand by utilizing local characteristics and industrial advantages. Conclusions : Although there are various problems that need to be solved to develop the water industry in Gyeongsangnam-do Province, the Korean government is making efforts to develop the water industry these days. It is necessary to establish and implement effective development strategies and policies for promoting the local water industry in Gyeongsangnam-do Province.

Effect of initial salt concentrations on cell performance and distribution of internal resistance in microbial desalination cells.

Yang, Euntae,Choi, Mi-Jin,Kim, Kyoung-Yeol,Chae, Kyu-Jung,Kim, In S Taylor Francis ; Publications Division, Selper Ltd 2015 Environmental Technology Vol.36 No.7

<P>Microbial desalination cells (MDCs) are modified microbial fuel cells (MFCs) that concurrently produce electricity and desalinate seawater, but adding a desalination compartment and an ion-exchange membrane may increase the internal resistance (Ri), which can limit the cell performance. However, the effects of a desalination chamber and initial NaCl concentrations on the internal resistances and the cell performances (i.e. Coulombic efficiency (CE), current and power density) of MDCs have yet to be thoroughly explored; thus, the cell performance and Ri distributions of MDCs having different initial concentrations and an MFC having no desalination chamber were compared. In the MDCs, the current and power density generation increased from 2.82???mA and 158.2???mW/m2 to 3.17???mA and 204.5???mW/m2 when the initial NaCl concentrations were increased from 5 to 30???g/L, as a consequence of the internal resistances decreasing from 2432.0 to 2328.4???곽. And even though the MFC has a lower Ri than the MDCs, lower cell performances (current: 2.59???mA; power density: 141.6???mW/m2 and CE: 62.1%) were observed; there was no effect of improved junction potential in the MFC. Thus, in the MDCs, the higher internal resistances due to the addition of a desalination compartment can be offset by reducing the electrolyte resistance and improving the junction potential at higher NaCl concentrations.</P>