Synthetic Deep Neural Network Design for Lidar-inertial Odometry Based on CNN and LSTM

Hyunjin Son,Byungjin Lee,성상경 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.8

This paper proposes an integrated navigation algorithm based on the deep learning method using lidar and inertial measurements. The proposed method develops a new synthetic structure of neural networks for implementing the Lidar-inertial odometry to generate a 6 degree of freedom pose estimation. The proposed network consists of component neural networks that reflect each sensor’s characteristics, then an integrating network for combining estimates from heterogeneous sensors at the terminal stage. To secure an efficient estimation performance, a compound loss function design is exploited. The performance of the proposed deep learning-based LIO algorithm was verified through artificially generated data sets based on a high fidelity dynamics simulator. Instead of using the well-known reference data set of ground vehicles, the employed data set reflects the full 3D dynamic characteristics of the drone as well as low-cost sensor characteristics considering onboard implementation. Through the flight simulator data set, the estimation performance of the proposed synthetic network was demonstrated.

Epidemiological characteristics of and containment measures for COVID-19 in Busan, Korea

Hyunjin Son,Hyojung Lee,Miyoung Lee,Youngduck Eun,Kyounghee Park,Seungjin Kim,Wonseo Park,Sora Kwon,Byoungseon Ahn,Dongkeun Kim,Changhoon Kim 한국역학회 2020 Epidemiology and Health Vol.42 No.-

OBJECTIVES: To describe and evaluate epidemiological investigation results and containment measures implemented in Busan, where 108 cases were confirmed with coronavirus disease 2019 (COVID-19) between February 21, 2020 and March 24, 2020. METHODS: Any individual who tested positive for COVID-19 was classified as a confirmed case. Measures were taken to identify the source of infection and trace and quarantine contacts. Serial intervals were estimated and the effective reproduction number was computed. RESULTS: Of the total 18,303 COVID-19 tests performed between January 16, 2020 and March 24, 2020 in Busan, 108 yielded positive results (positive test rate, 0.6%). All confirmed cases were placed in isolation at hospitals. Of the 108 confirmed cases, 59 (54.6%) were female. The most common age group was 20-29 years with 37 cases (34.3%). Regarding symptoms at the time of diagnosis, cough (n=38, 35.2%) and fever (n=34, 31.5%) were most common; 12 cases (11.1%) were asymptomatic. The source of infection was identified in 99 cases (91.7%). A total of 3,223 contacts were identified and quarantined. Household contacts accounted for 196, and the household secondary attack rate was 8.2% (95% confidence interval [CI], 4.7 to 12.9). The mean serial interval was estimated to be 5.54 days (95% CI, 4.08 to 7.01). After February 26, (Rt) remained below 1 in Busan. CONCLUSIONS: The early containment strategy implemented in Busan shows that control is possible if outbreaks are of limited scope. In preparation for future outbreaks, public health and healthcare systems should be re-examined and put in a ready state.

초소형 관성측정모듈을 이용한 플라잉디스크의 수평축 모멘트 미계수 추정 연구

손현진(Hyunjin Son),이주환(Ju Hwan Lee),이영재(Young Jae Lee),성상경(Sangkyung Sung) 한국항공우주학회 2018 韓國航空宇宙學會誌 Vol.46 No.5

본 논문은 플라잉디스크에 탑재된 계측모듈의 IMU 데이터를 이용하여 롤링 및 피칭모멘트 감쇠미계수를 추정하는 방식을 새롭게 제시한다. 제안한 방식은 반복된 수 회의 원반비행 실험을 수행하여 데이터를 구축한 뒤 공력 계수를 추정하므로, 풍동이나 전산유체해석을 이용하는 방법에 비해 수월한 실험적 대안이 될 수 있다. 추정한 공력 계수는 플라잉디스크의 비행동역학 모델을 토대로 구현한 시뮬레이터에 적용하여 비행 궤적을 예측하는 것에 이용되었으며, 이를 GPS의 위치 궤적과 비교함으로써 성능을 검증하였다. This paper suggests a new method to estimate the roll and pitch damping moment coefficients of a flying disc through sensor data from the onboard IMU module. This method can be easily performed than wind tunnel or computational fluid dynamics methods because it estimates aerodynamic coefficients simply after accumulating the inertial data through several repeated flight experiments. Estimated coefficients are applied to a simulator which is based on the flight dynamics of a flying disc. Finally, the predicted flight trajectory is compared with the true position provided by GPS, which demonstrated the validity of the proposed estimation method.

Protection against RAGE-mediated neuronal cell death by sRAGE-secreting human mesenchymal stem cells in 5xFAD transgenic mouse model

Son, Myeongjoo,Oh, Seyeon,Park, Hyunjin,Ahn, Hyosang,Choi, Junwon,Kim, Hyungho,Lee, Hye Sun,Lee, Sojung,Park, Hye-Jeong,Kim, Seung U.,Lee, Bonghee,Byun, Kyunghee Elsevier 2017 Brain, behavior, and immunity Vol.66 No.-

<P><B>Abstract</B></P> <P>Alzheimer's disease (AD), which is the most commonly encountered neurodegenerative disease, causes synaptic dysfunction and neuronal loss due to various pathological processes that include tau abnormality and amyloid beta (Aβ) accumulation. Aβ stimulates the secretion and the synthesis of Receptor for Advanced Glycation End products (RAGE) ligand by activating microglial cells, and has been reported to cause neuronal cell death in Aβ<SUB>1–42</SUB> treated rats and in mice with neurotoxin-induced Parkinson’s disease.</P> <P>The soluble form of RAGE (sRAGE) is known to reduce inflammation, and to decrease microglial cell activation and Aβ deposition, and thus, it protects from neuronal cell death in AD. However, sRAGE protein has too a short half-life for therapeutic purposes. We developed sRAGE-secreting umbilical cord derived mesenchymal stem cells (sRAGE-MSCs) to enhance the inhibitory effects of sRAGE on Aβ deposition and to reduce the secretion and synthesis of RAGE ligands in 5xFAD mice. In addition, these cells improved the viability of injected MSCs, and enhanced the protective effects of sRAGE by inhibiting the binding of RAGE and RAGE ligands in 5xFAD mice. These findings suggest sRAGE protein from sRAGE-MSCs has better protection against neuronal cell death than sRAGE protein or single MSC treatment by inhibiting the RAGE cell death cascade and RAGE-induce inflammation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> sRAGE enhanced viability of MSCs in 5xFAD mice. </LI> <LI> sRAGE-MSCs showed low Aβ<SUB>1–42</SUB> levels and protective effects from RAGE-mediated neuronal cell death microglia activation in 5xFAD mice. </LI> <LI> Comparing sRAGE protein and MSCs, the sRAGE protein effectively modulated expression of RAGE ligands and control MSC has protective effects from neuron apoptosis in 5xFAD mice. </LI> </UL> </P>

Synthesizing diffusion tensor imaging from functional MRI using fully convolutional networks

Son, Seong-Jin,Park, Bo-yong,Byeon, Kyoungseob,Park, Hyunjin Elsevier 2019 Computers in biology and medicine Vol.115 No.-

<P><B>Abstract</B></P> <P><B>Purpose</B></P> <P>Medical image synthesis can simulate a target modality of interest based on existing modalities and has the potential to save scanning time while contributing to efficient data collection. This study proposed a three-dimensional (3D) deep learning architecture based on a fully convolutional network (FCN) to synthesize diffusion-tensor imaging (DTI) from resting-state functional magnetic resonance imaging (fMRI).</P> <P>Methods: fMRI signals derived from white matter (WM) exist and can be used for assessing WM alterations. We constructed an initial functional correlation tensor image using the correlation patterns of adjacent fMRI voxels as one input to the FCN. We considered T1-weighted images as an additional input to provide an algorithm with the structural information needed to synthesize DTI. Our architecture was trained and tested using a large-scale open database dataset (training n = 648; testing n = 293).</P> <P><B>Results</B></P> <P>The average correlation value between synthesized and actual diffusion tensors for 38 WM regions was 0.808, which significantly improves upon an existing study (<I>r</I> = 0.480). We also validated our approach using two open databases. Our proposed method showed a higher correlation with the actual diffusion tensor than the conventional machine-learning method for many WM regions.</P> <P><B>Conclusions</B></P> <P>Our method synthesized DTI images from fMRI images using a 3D FCN architecture. We hope to expand our method of synthesizing various other imaging modalities from a single image source.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Diffusion-tensor imaging was synthesized from functional magnetic resonance imaging. </LI> <LI> 3D fully convolutional network was proposed. </LI> <LI> Our method was trained and tested using a large-scale open database dataset. </LI> <LI> Our approach was tested for both normal and diseased cases. </LI> </UL> </P>

The effects of doxorubicin-loaded liposomes on viability, stem cell surface marker expression and secretion of vascular endothelial growth factor of three-dimensional stem cell spheroids

Lee, Hyunjin,Son, Jihwan,Na, Chae-Bin,Yi, Gawon,Koo, Heebeom,Park, Jun-Beom D.A. Spandidos 2018 Experimental and therapeutic medicine Vol.15 No.6

<P>The aim of the present study was to evaluate the effects of anionic, cationic and neutral liposomes containing doxorubicin on the cellular viability and osteogenic differentiation of three-dimensional stem cell spheroids. Doxorubicin-loaded liposomes were prepared using the traditional thin-lipid-film-hydration method and were characterized using transmission electron microscopy and a zeta potential analyzer. The doxorubicin release profile from these liposomes was also analyzed <I>in vitro</I>. Three-dimensional cell spheroids were fabricated using silicon elastomer-based concave microwells. Qualitative results of cellular viability were observed using a confocal microscope and quantitative cellular viability was evaluated using a Cell-Counting Kit-8 (CCK-8) assay. Furthermore, the secretion of vascular endothelial growth factor was evaluated. Western blot analysis was performed to assess the expression of collagen I and glyceraldehyde 3-phosphate. Results indicated that the spheroids were well formed in silicon elastomer-based concave microwells on day 1. In general, the shapes of the cells in the in the doxorubicin-loaded anionic, cationic and neutral liposome groups were similar to the control group except for the 10 µg/ml groups on days 3, 5, and 7. No significant changes in cellular viability were noted with the addition of doxorubicin at day 1 but significant decreases in cellular viability were noted with application of doxorubicin at day 5. Notably, higher concentrations of doxorubicin reduced the secretion of vascular endothelial growth factor and stem cell marker expression. To conclude, the present study indicated that doxorubicin-loaded anionic liposomes produced the most sustained release profile and cationic liposomes produced the highest uptake of the stem cell spheroids. These findings suggested that higher concentrations of doxorubicin-loaded liposomes affected cellular viability, the secretion of vascular endothelial growth factor and stem cell marker expression.</P>

병렬 분할된 CMOS 점증 단권변압기와 모델링

안현진(Hyunjin Ahn),손병찬(Byung Chan Son),류현식(Hyunsik Ryu),이옥구(Ockgoo Lee) 한국전자파학회 2020 한국전자파학회논문지 Vol.31 No.11

본 논문에서는 임피던스 변환율을 개선하기 위한 병렬 분할된 CMOS 점증 단권변압기를 제안한다. 또한, 이에 상응하는 확장성이 있는 CMOS 공정을 사용한 병렬 분할 기법을 사용한 모델링이 개발되었다. 제안된 병렬 분할 기법의 모델링을 사용하여 병렬 분할된 단권변압기의 정확한 성능 예측이 가능하다. 병렬 분할된 점증 단권변압기는 표준 CMOS 65 ㎚ 공정을 사용하여 제작되었다. 모델링된 결과는 측정된 결과와 우수한 일치를 보여준다. 제작된 1개/2개 병렬 분할된 CMOS 점증 단권변압기는 3 ㎓ 주파수에서 −1.21 ㏈/−1.54 ㏈의 최소삽입손실의 특성을 보이며, 50 Ω 임피던스가 9.5 Ω/6.1 Ω의 임피던스로 변환되어 보인다. In this study, a parallel-segmented complementary metal-oxide–semiconductor (CMOS) step-up autotransformer was developed to improve the impedance transformation ratio. In addition, a corresponding scalable segmentation-based model was developed on a CMOS case. The proposed segmentation-based model was used to predict the accurate performance of a parallel-segmented autotransformer. The parallel-segmented step-up autotransformer was fabricated through a standard 65 ㎚ CMOS process. The modeled results showed good agreement with the measured results. The implemented one/two parallel-segmented CMOS step-up autotransformer changed the impedance from 50 Ω to 9.5 Ω/6.1 Ω with −1.21 ㏈/−1.54 ㏈ minimum insertion loss at 3 ㎓.

보험시장에서의 거래구조 문제와 소비자보호제도에 대한 소비자평가 연구

백현진(Hyunjin Baek),손지연(Jiyeon Son),최현자(Hyuncha Choe) 한국FP학회 2020 Financial Planning Review Vol.13 No.2

본 연구는 한국소비자원의 대규모 소비자조사인 「2017 소비자시장평가지표」 원자료(N=1,000)를 활용하여 생명보험과 손해보험 시장의 거래구조 문제와 소비자보호제도에 대해 소비자가 어떻게 평가하고 있는지 살펴보고, 이들 간의 관계를 규명한 것이다. 주요 연구결과는 다음과 같다. 먼저 생명보험과 손해보험 모두에 있어 정보비대칭에 대한 문제인식, 교섭력차이에 대한 문제인식 그리고 이해상충에 대한 문제인식 각각의 평균점수는 큰 차이가 없었다. 그리고 보험소비자보호제도에 대한 소비자평가는 생명보험 및 손해보험에 있어 각 10점 만점에 평균 8.19점과 8.25점으로 나타났다. 다음으로 거래구조 문제에 대한 소비자인식이 소비자보호제도에 대한 소비자의 평가에 미치는 영향을 분석한 결과, 생명보험과 손해보험 모두에서 정보비대칭에 대한 문제인식의 영향력이 가장 크게 나타났으며, 교섭력차이에 대한 문제인식, 그리고 이해상충에 대한 문제인식이 그 뒤를 잇는 것으로 나타났다. 이상의 분석 결과는 소비자의 시각과 눈높이에서 보험시장에 대한 소비자보호제도를 평가한 결과를 분석한 것으로, 보험시장에서의 소비자지향성을 향상시키기 위해서는 거래구조 문제 중 정보비대칭 문제가 가장 우선적으로 해소되어야 함을 시사한다. 본 연구의 결과는 보험시장에서의 소비자보호제도를 소비자가 희망하는 방향으로 추진하기 위해 필요한 보완책을 마련하는데 기여할 수 있다. It is well-known that the transaction structure of insurance markets includes three types of consumer issues: information asymmetry, differences in bargaining power, and conflicts of interest. Using the data from “Consumer Markets Evaluation Indicators in Korea” generated by the Korea Consumer Agency in 2017, this study aimed to examine the relationship between consumers’ evaluation of transaction structure and consumers’ evaluation of consumer protection systems, with respect to life and non-life insurance markets. First, in both life and non-life insurance markets, no significant differences were exhibited amongst the levels of consumer evaluation of the three types of consumer issues. Moreover, the average consumer evaluation of the consumer protection system was 8.19/10 for the life insurance market and 8.25/10 for the non-life insurance market. Second, the results of the regression analyses of factors affecting consumer evaluation of the consumer protection system in life and non-life insurance markets reveal that information asymmetry had the highest impact among the three types of consumer issues. In other words, policy makers should reduce the level of information asymmetry with priority, in order to enhance the consumer evaluation level of consumer protection systems in life and non-life insurance markets. This study can provide valuable insights for policy makers who want to develop consumer-oriented consumer protection strategies in insurance markets.

Versatile 3D porous recycled carbon garments with fully-loaded active materials in the current collector for advanced lithium-ion batteries

Cho, Hyunjin,Kim, Yeonho,Yun, Yong Ju,Lee, Kyu Seung,Shim, Jaeho,Lee, Chil-Hyoung,Seo, Jin Won,Hong, Won G.,Kim, Hae Jin,Kim, Hak Yong,Son, Dong Ick Elsevier Science Ltd 2019 Composites Part B, Engineering Vol. No.

<P><B>Abstract</B></P> <P>We have developed a new and versatile three-dimensional (3D) porous and the conductive carbon spun fabric (CSF) structure and applied it to the current collector for advanced lithium-ion batteries (LIBs). The 3D porous CSF are manufactured from recycled oxidized polyacrylonitrile (Oxi-PAN) staple fibers via the spinning, the knitting, stabilization, and carbonization process in order. Furthermore, we have demonstrated the conductive T-shirts and gloves and investigated the structural, electrical, mechanical, and thermal properties of the CSF through various analytical methods including Joule heating simulation as well as the deformation simulation. The CSF with its 3D porous structure is applied as a current collector for advanced lithium batteries in order to replace the conventionally used metal-based current collector. During battery performances, the porous 3D network structure of the CSF provides effective diffusion pathway for lithium ions during the charge/discharge processes. Consequently, the CSF shows not only the improved cycling stability than that of the conventional aluminum current collector but also demonstrating high-rate performances at high percentage loading of active materials in the current collector. The pouch-type LIBs with the CSF/LiFePO<SUB>4</SUB> composites electrode exhibits excellent mechanical stability and flexibility with showing a discharge capacity of 148.7 mA h g<SUP>−1</SUP> at 2 C over 250 cycles over the 1200 times bending with a radius of 12 mm.</P> <P><B>Graphical abstract</B></P> <P>A new and versatile three-dimensional (3D) porous and the conductive carbon spun fabric (CSF) structure have been developed and have been applied it to the current collector for advanced lithium-ion batteries (LIBs).</P> <P>[DISPLAY OMISSION]</P>

RF SoC를 활용한 GNSS Spoofer 설계

최현진(Hyunjin Choi),전태현(Taehyun Jun),손석보(Seokbo Son),박일규(Ilkyu Park),고범준(Bumjun Ko),강창옥(Changok Kang) 항공우주시스템공학회 2023 항공우주시스템공학회 학술대회 발표집 Vol.2023 No.05