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11,101 results on '"Choi, Ji-An"'

126. Event Camera Based Real-Time Detection and Tracking of Indoor Ground Robots

Author

Patel, Himanshu, Iaboni, Craig, Lobo, Deepan, Choi, Ji-won, and Abichandani, Pramod

Subjects
Computer Science - Computer Vision and Pattern Recognition
Abstract

This paper presents a real-time method to detect and track multiple mobile ground robots using event cameras. The method uses density-based spatial clustering of applications with noise (DBSCAN) to detect the robots and a single k-dimensional ($k - d$) tree to accurately keep track of them as they move in an indoor arena. Robust detections and tracks are maintained in the face of event camera noise and lack of events (due to robots moving slowly or stopping). An off-the-shelf RGB camera-based tracking system was used to provide ground truth. Experiments including up to 4 robots are performed to study the effect of i) varying DBSCAN parameters, ii) the event accumulation time, iii) the number of robots in the arena, iv) the speed of the robots, and v) variation in ambient light conditions on the detection and tracking performance. The experimental results showed 100% detection and tracking fidelity in the face of event camera noise and robots stopping for tests involving up to 3 robots (and upwards of 93% for 4 robots). When the lighting conditions were varied, a graceful degradation in detection and tracking fidelity was observed.

Published
2021

139. Epitaxial single-crystal growth of transition metal dichalcogenide monolayers via atomic sawtooth Au surface

Author

Choi, Soo Ho, Kim, Hyung-Jin, Song, Bumsub, Kim, Yong In, Han, Gyeongtak, Ko, Hayoung, Boandoh, Stephen, Choi, Ji Hoon, Oh, Chang Seok, Jin, Jeong Won, Yun, Seok Joon, Shin, Bong Gyu, Jeong, Hu Young, Kim, Young-Min, Han, Young-Kyu, Lee, Young Hee, Kim, Soo Min, and Kim, Ki Kang

Subjects
Condensed Matter - Materials Science
Abstract

Growth of two-dimensional van der Waals layered single-crystal (SC) films is highly desired to manifest intrinsic material sciences and unprecedented devices for industrial applications. While wafer-scale SC hexagonal boron nitride film has been successfully grown, an ideal growth platform for diatomic transition metal dichalcogenide (TMdC) film has not been established to date. Here, we report the SC growth of TMdC monolayers in a centimeter scale via atomic sawtooth gold surface as a universal growth template. Atomic tooth-gullet surface is constructed by the one-step solidification of liquid gold, evidenced by transmission-electron-microscopy. Anisotropic adsorption energy of TMdC cluster, confirmed by density-functional calculations, prevails at the periodic atomic-step edge to yield unidirectional epitaxial growth of triangular TMdC grains, eventually forming the SC film, regardless of Miller indices. Growth using atomic sawtooth gold surface as a universal growth template is demonstrated for several TMdC monolayer films, including WS2, WSe2, MoS2, MoSe2/WSe2 heterostructure, and W1-xMoxS2 alloy. Our strategy provides a general avenue for the SC growth of diatomic van der Waals heterostructures in a wafer scale, to further facilitate the applications of TMdCs in post silicon technology., Comment: The supporting information is included in the manuscript file

Published
2020

140. Dual Precision Deep Neural Network

Author

Park, Jae Hyun, Choi, Ji Sub, and Ko, Jong Hwan

Subjects
Computer Science - Machine Learning, Computer Science - Computer Vision and Pattern Recognition
Abstract

On-line Precision scalability of the deep neural networks(DNNs) is a critical feature to support accuracy and complexity trade-off during the DNN inference. In this paper, we propose dual-precision DNN that includes two different precision modes in a single model, thereby supporting an on-line precision switch without re-training. The proposed two-phase training process optimizes both low- and high-precision modes., Comment: 5 pages, 4 figures, 2 tables

Published
2020
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141. Instant, multiscale dry transfer printing by atomic diffusion control at heterogeneous interfaces

Author

Heo, Seungkyoung, Ha, Jeongdae, Son, Sook Jin, Choi, In Sun, Lee, Hyeokjun, Oh, Saehyuck, Jekal, Janghwan, Kang, Min Hyung, Lee, Gil Ju, Jung, Han Hee, Yea, Junwoo, Lee, Taeyoon, Lee, Youngjeon, Choi, Ji-Woong, Xu, Sheng, Choi, Joon Ho, Jeong, Jae-Woong, Song, Young Min, Rah, Jong-Cheol, Keum, Hohyun, and Jang, Kyung-In

Subjects
Clinical Research
Abstract

Transfer printing is a technique that integrates heterogeneous materials by readily retrieving functional elements from a grown substrate and subsequently printing them onto a specific target site. These strategies are broadly exploited to construct heterogeneously integrated electronic devices. A typical wet transfer printing method exhibits limitations related to unwanted displacement and shape distortion of the device due to uncontrollable fluid movement and slow chemical diffusion. In this study, a dry transfer printing technique that allows reliable and instant release of devices by exploiting the thermal expansion mismatch between adjacent materials is demonstrated, and computational studies are conducted to investigate the fundamental mechanisms of the dry transfer printing process. Extensive exemplary demonstrations of multiscale, sequential wet-dry, circuit-level, and biological topography-based transfer printing demonstrate the potential of this technique for many other emerging applications in modern electronics that have not been achieved through conventional wet transfer printing over the past few decades.

Published
2021

142. Functional annotation of the 2q35 breast cancer risk locus implicates a structural variant in influencing activity of a long-range enhancer element

Author

Baxter, Joseph S, Johnson, Nichola, Tomczyk, Katarzyna, Gillespie, Andrea, Maguire, Sarah, Brough, Rachel, Fachal, Laura, Michailidou, Kyriaki, Bolla, Manjeet K, Wang, Qin, Dennis, Joe, Ahearn, Thomas U, Andrulis, Irene L, Anton-Culver, Hoda, Antonenkova, Natalia N, Arndt, Volker, Aronson, Kristan J, Augustinsson, Annelie, Becher, Heiko, Beckmann, Matthias W, Behrens, Sabine, Benitez, Javier, Bermisheva, Marina, Bogdanova, Natalia V, Bojesen, Stig E, Brenner, Hermann, Brucker, Sara Y, Cai, Qiuyin, Campa, Daniele, Canzian, Federico, Castelao, Jose E, Chan, Tsun L, Chang-Claude, Jenny, Chanock, Stephen J, Chenevix-Trench, Georgia, Choi, Ji-Yeob, Clarke, Christine L, Collaborators, NBCS, Colonna, Sarah, Conroy, Don M, Couch, Fergus J, Cox, Angela, Cross, Simon S, Czene, Kamila, Daly, Mary B, Devilee, Peter, Dörk, Thilo, Dossus, Laure, Dwek, Miriam, Eccles, Diana M, Ekici, Arif B, Eliassen, A Heather, Engel, Christoph, Fasching, Peter A, Figueroa, Jonine, Flyger, Henrik, Gago-Dominguez, Manuela, Gao, Chi, García-Closas, Montserrat, García-Sáenz, José A, Ghoussaini, Maya, Giles, Graham G, Goldberg, Mark S, González-Neira, Anna, Guénel, Pascal, Gündert, Melanie, Haeberle, Lothar, Hahnen, Eric, Haiman, Christopher A, Hall, Per, Hamann, Ute, Hartman, Mikael, Hatse, Sigrid, Hauke, Jan, Hollestelle, Antoinette, Hoppe, Reiner, Hopper, John L, Hou, Ming-Feng, Investigators, kConFab, Investigators, ABCTB, Ito, Hidemi, Iwasaki, Motoki, Jager, Agnes, Jakubowska, Anna, Janni, Wolfgang, John, Esther M, Joseph, Vijai, Jung, Audrey, Kaaks, Rudolf, Kang, Daehee, Keeman, Renske, Khusnutdinova, Elza, Kim, Sung-Won, Kosma, Veli-Matti, Kraft, Peter, Kristensen, Vessela N, Kubelka-Sabit, Katerina, Kurian, Allison W, Kwong, Ava, and Lacey, James V

Subjects
Human Genome, Genetics, Cancer, Estrogen, Prevention, Breast Cancer, 2.1 Biological and endogenous factors, Aetiology, Breast Neoplasms, CRISPR-Cas Systems, Cell Line, Chromosome Mapping, Chromosomes, Human, Pair 2, Female, Genetic Association Studies, Genetic Variation, Humans, Insulin-Like Growth Factor Binding Protein 5, Molecular Sequence Annotation, Promoter Regions, Genetic, Risk Factors, Sequence Deletion, NBCS Collaborators, kConFab Investigators, ABCTB Investigators, breast cancer risk, functional annotation, risk locus, Biological Sciences, Medical and Health Sciences, Genetics & Heredity
Abstract

A combination of genetic and functional approaches has identified three independent breast cancer risk loci at 2q35. A recent fine-scale mapping analysis to refine these associations resulted in 1 (signal 1), 5 (signal 2), and 42 (signal 3) credible causal variants at these loci. We used publicly available in silico DNase I and ChIP-seq data with in vitro reporter gene and CRISPR assays to annotate signals 2 and 3. We identified putative regulatory elements that enhanced cell-type-specific transcription from the IGFBP5 promoter at both signals (30- to 40-fold increased expression by the putative regulatory element at signal 2, 2- to 3-fold by the putative regulatory element at signal 3). We further identified one of the five credible causal variants at signal 2, a 1.4 kb deletion (esv3594306), as the likely causal variant; the deletion allele of this variant was associated with an average additional increase in IGFBP5 expression of 1.3-fold (MCF-7) and 2.2-fold (T-47D). We propose a model in which the deletion allele of esv3594306 juxtaposes two transcription factor binding regions (annotated by estrogen receptor alpha ChIP-seq peaks) to generate a single extended regulatory element. This regulatory element increases cell-type-specific expression of the tumor suppressor gene IGFBP5 and, thereby, reduces risk of estrogen receptor-positive breast cancer (odds ratio = 0.77, 95% CI 0.74-0.81, p = 3.1 × 10-31).

Published
2021

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