Fast identification of short, sound-soft open arcs by the orthogonality sampling method in the limited-aperture inverse scattering problem
The orthogonality sampling method (OSM) is a recently developed non-iterative technique for imaging and identifying targets in inverse scattering problems. In this paper, a set of short sound-soft open arcs is obtained by OSM in the limited-aperture inverse scattering problem.
의료수학연구부 | Chi Young Ahn; Seongje Chae; Won-Kwang Park*
A multi-stage SIR model for rumor spreading
We propose a multi-stage structured rumor spreading model that consists of ignorant, new spreader, old spreader, and stifler. We derive a mean field equation to obtain the multi-stage structured model on homogeneous networks.
의료수학연구부 | Sun-Ho Choi; Hyowon Seo*, MINHA YOO
Low-dose CT Image Reconstruction with a Deep Learning Prior
In low-dose computed tomography (LDCT), a penalized weighted least squares (PWLS) approach that incorporates the Poisson statistics of X-ray photons can significantly reduce excessive quantum noise.
의료수학연구부 | HYOUNG SUK PARK; KIWAN Jeon*; KYUNGSANG KIM
Single- and Multi-Frequency Direct Sampling Methods in a Limited-Aperture Inverse Scattering Problem
Although the direct sampling method (DSM) has demonstrated its feasibility and robustness for imaging of small inhomogeneities, mathematical analyses of DSM have been conducted only on the full-aperture inverse scattering problem.
의료수학연구부 | SANGWOO KANG; MARC LAMBERT; CHI YOUNG AHN; TAEYOUNG HA; and WON-KWANG PARK
Conference
Symposium on Medical Mathematics of the National Institute of Surgical Science at the center of the Fourth Industrial Revolution
The National Research Institute for Mathematical Sciences aims to inform the public of the vision and implementation plan for industrial and medical mathematics. The Medical Mathematics Symposium will be held as follows: We ask for your attention and participation. - Name of the event: Symposium on Medical Mathematics of the National Institute of Surgical Science at the center of the Fourth Industrial Revolution - Pause: February 28, 2019 (Text) 10:30 to 15:00 - Location: Conference Room I-A101 of the Institute of Convergence Technology (145) Gwanggyo-ro, Yeongtong-gu, Suwon - Inquiry: Industrial Mathematical Innovation Center (031-5171-5200)
2019-02-28 ~ 2019-02-28
Colloquium
The interface between gravitational wave detection and earthquake science
○ Title: The interface between gravitational wave detection and earthquake science - Professor, California Institute of Technology - Senior Researcher (DR2), Institute de Recherche pour le Developpement, Excellence Chair at Universite Cote d’Azur, Geoazur Laboratory - Seismology, Earth Science ○ Abstract: Recent studies reported the observation of prompt elastogravity signals during the 2011 M9.1 Tohoku earthquake, recorded with broadband seismometers and gravimeter between the rupture onset and the arrival of the seismic waves. Here we show that to extend the range of magnitudes over which the gravity perturbations can be observed and reduce the time needed for their detection, high-precision gravity strainmeters under development could be used, such as torsion bars, superconducting gradiometers or strainmeters based on atom interferometers. These instruments measure the differential gravitational acceleration between two seismically isolated test masses, and are designed to observe signals around 0.1 Hz. We show that these instruments should be able to detect prompt gravity perturbations induced by earthquakes larger than M7, up to 1000 km from the earthquake centroid within P-waves travel time and up to 120 km within the first 10 seconds of rupture onset, provided a sensitivity in gravity strain of 10-15 Hz-1/2 at 0.1 Hz can be achieved. The analysis involves simulations of the expected gravity strain signals based on an analytical model of gravity perturbations generated by fault rupture in a homogeneous half-space. As an immediate application, we discuss the possibility to improve current earthquake-early warning systems (EEWS). Our results suggest that, in comparison to conventional P-wave-based EEWS, a gravity-based warning system could perform faster detections of large off-shore subduction earthquakes (at least larger than M7.4). Gravity strainmeters could also perform earlier magnitude estimates, within the duration of the fault rupture, and therefore complement current tsunami warning systems.
2018-11-21
Seminar
AI and Industrial Mathematical Forum Guide (Daejeon Creative Economy Innovation Center)
The event will involve about 100 participants from companies and start-ups in Daejeon, introducing research and industrial mathematics, troubleshooting cases, It will consist of research and cross-enterprise networking. Since this is the first time for business to be traded in Daejeon, we ask the department manager, PI, and interested researchers to participate. The attached file is an event plan and I'll let you know once the program is finalized. Please let me know if you have any questions. □ Purpose ○ Introduce industrial mathematics concept and share cases such as artificial intelligence and big data analysis to solve corporate problems and increase sales ○ Activating a collaborative ecosystem between research institutes and engineers by matching companies interested in solving corporate problems using industrial mathematics such as artificial intelligence, big data analysis, and optimization □ Period ○ October 25th 14:00-17:00 □ Location ○ Daejeon Creative Economy Innovation Center (KAIST 9F) □ Subject presentation ○ Artificial intelligence based on industrial mathematics
2018-10-25
Conference
Ice Sheet Dynamics Model Workshops
Workshop program(tentative) Title: Ice Sheet Dynamics Model Workshops Date &time: 9 Oct. – 12 Oct. 2018 Venue: NIMS CAMP Workshop Webpage: https://camp.nims.re.kr/activities/eventpages/?id=207839&action=overview Aim &Scope: We organize this workshop to fulfill the followings: To better understand and implement the ice sheet dynamics models like ISSM and PISM, To refine the ice sheet models more efficiently, and To discuss the recent topics related to implementation and development of the models. Speakers(tentative) PISM: Andy Aschwanden, Constantine Khroulev (U. of Alaska), (Ricarda Winkelmann(PIK)) ISSM: Eric Larour, Surendra Adhikari(NASA/JPL), Mathieu Morlighem(UCI) NIMS: Dong-Uk Hwang, Yeontaek Choi KOPRI: Emilia Kyung Jin/(Won-Sang Lee) Dong-A Univ.: Young-sam Kwon Time schedule 9 Oct. 2018, Tuesday (Korea National Holiday) 10:00 – 10:30 Registration 10:30 – 11:30 Special Talk (Young-sam Kwon, Dong-A Univ.) “Mathematical &Numerical topics of Ice Sheet dynamics” 11:30 – 12:30 Lunch 12:30 – 17:30 Social Program 17:30 – 19:30 Discussion and Dinner “Present and Future Hot topics on Ice Flow Dynamics” 10 Oct. 2018, Wednesday 09:30 – 09:50 Registration 09:50 – 10:00 Opening remarks (NIMS president) 10:00 – 10:30 Division Mission (Dong-Uk Hwang, NIMS) 10:30 - 11:00 Ice Sheet Dynamics Team Mission (Yeontaek Choi, NIMS) 11:00 – 11:30 Collaboration with KOPRI (Emilia Kyung Jin, KOPRI) “Improving Future Projections of Antarctica: Observations and Modeling” 11:30 – 12:00 Introduction to participants (Tentative) 12:00 – 14:00 Lunch 14:00 – 14:30 PISM Session 1 (Andy Aschwanden, Geophysical Inst., Univ. of Alaska) “Introduction into ice sheet flow” 14:30 – 15:40 PISM Session 2 (Andy Aschwanden, Geophysical Inst., Univ. of Alaska) “The Parallel Ice Sheet Model (PISM)” 15:40 – 16:00 Break 16:00 – 15:40 PISM Session 3 (Constantine Khroulev, Geophysical Inst., Univ. of Alaska) “PISM: What it does and how it does it” 18:00 – 20:00 Banquet 11 Oct. 2018, Thursday 09:00 – 10:40 PISM Session 4 (Constantine Khroulev, Geophysical Inst., Univ. of Alaska) “Customizing and extending PISM” 10:40 – 11:00 Break 11:00 - 12:40 ISSM Session 1 (Eric Larour, NASA JPL) “ISSM Introduction and Capabilities: a Quick Start” 12:40 – 14:30 Lunch 14:30 – 16:10 ISSM Session 2 (Mathieu Morlighem, Univ. of California Irvine) “Pine Island Glacier: a simulation and experiments” 16:10 – 16:30 Break 16:30 – 18:10 ISSM Session 3 (Surendra Adhikari, NASA JPL) “Sea-level in South Korea due to global cryospheric changes” 18:10 – 20:00 Dinner 12 Oct. 2018, Friday 09:30 – 10:30 Collaboration Discussion (NIMS, KOPRI, ISSM team, PISM team) 10:30 – 12:00 Concluding discussion “The uncertainty mitigation in prediction of ice sheet mass change with Ice Sheet Dynamic Models” 12:00 ? 14:00 Lunch 14:00 ? 14:30 Dismissal Note: In PISM sessions, the lecturer prepared a VirtualBox (https://www.virtualbox.org) image with PISM already installed, so that we suggest that the audience should have VirtualBox installed on their laptops, and, in ISSM sessions, the audience need Mac OS X system with Matlab installed.
2018-10-09 ~ 2018-10-12
NIMS has solved Seoul Metro's problem of predicting and detecting mechanical equipment failure in subway stations
NIMS has solved Seoul Metro's problem of predicting and detecting mechanical equipment failure in subway stations NIMS and Seoul Metro succeeded in developing an automatic detection model for major parts and abnormalities applicable to various air conditioners in subway stations through joint research of 'Developing algorithm for mechanical equipment failure in subway stations in Seoul'. Ventilation facilities at subway stations are important facilities responsible for cooling and pleasant internal air, but the frequency of breakdowns has been steadily increasing lately due to the aging of equipment, and a lot of maintenance costs have been put in place. In response, Seoul Metro commissioned NIMS in May last year to develop mathematical data analysis methods for efficient control and maintenance of ventilation facilities. NIMS Researchers conducted a pattern analysis on the condition and conditions of components by utilizing current data collected from air conditioners (transmission fans) in subway ventilation rooms and actual date of replacement of parts.
2019-07-04
NIMS Industrial Mathematical Problem Solving Workshop in the First Half of 2019
NIMS Industrial Mathematical Problem Solving Workshop in the First Half of 2019 NIMS held a workshop on solving problems in NIMS industrial mathematics in the first half of 2019, for three days from June 26 to 28 The Industrial Mathematics Problem Solving Workshop is an event designed to bring together mathematical science researchers such as mathematicians, engineers and others to present solutions through mathematical modeling, optimization, and data analysis. In this workshop, three industry issues commissioned by companies and an institute were presented: △ scoring of oral health results, △ simulating nanofilter performance prediction, △ predicting erosion of low-orbital satellite components of atomic oxygen. About 150 researchers in related fields, consisting of NIMS researchers, NIMS industrial mathematics experts' group, professors, and graduate students, conducted a process of mathematically defining and discussing the proposed problem and presenting and discussing theoretical methodologies.
2019-07-04
NIMS-Busan City, Arrangements for the Promotion of Medical and Healthcare Industry
NIMS-Busan City, Arrangements for the Promotion of Medical and Healthcare Industry The NIMS and Busan City signed a business agreement to foster the medical and healthcare industries at the Busan University Hospital's grand auditorium on June 5 and held a joint symposium. The agreement was arranged to promote mutual cooperation with companies, hospitals and universities through the hosting of NIMS Medical Mathematics Center (scheduled for 2023), which has fostered the field of medical mathematics research as a representative brand in the Echo Delta Smart City Healthcare Cluster in Busan since the end of last year. Major agreements include △ fostering and providing mutual support in the science and technology fields and medical and healthcare industries, △ promoting joint projects related to smart healthcare clusters, △ exchanging manpower, facilities, equipment and space for the establishment of Medical Mathematics Center, △ analyzing big data, and planning new medical-related projects using AI. Through this agreement, NIMS is planning to present solutions to problems that occur in the field of businesses and public organizations through mathematical analysis of huge data related to health care, and to provide customized support for industries such as convergence research using mathematical techniques such as deep learning.
2019-07-04
NIMS-Seoul Metro signed a business partnership agreement
NIMS-Seoul Metro signed a business partnership agreement On December 20, NIMS and the Seoul Metro signed a business partnership agreement to apply the mathematical failure prediction algorithm to the automatic control of subway machines and equipment. The two agencies agreed to: △ provide analysis and resolution for adding mathematical failure prediction algorithms to the SAMBA(Smart Automatic Mechanical Big data Analysis System), △ provide relevant data to increase the value of industrial math utilization, and to share performance. Researchers from both organizations plan to develop mathematical data analysis methods that can be used to predict and detect mechanical equipment failures and to explore ways that can be applied to equipment in all subway stations.
2018-12-24
The 2nd NIMS Industrial Math Problem Solving Workshop
The 2nd NIMS Industrial Math Problem Solving Workshop The 2nd NIMS industrial math problem solving workshop in 2018 was held for three days from December 17 to 19. This workshop is designed to solve three industry issues commissioned by companies: improvement of similar document detection system using natural language processing algorithms, reliability of oral strength measurement results through deep learning, and analysis of XOR computation and pattern analysis for semiconductor-based storage device data recovery. More than 150 experts from related fields, including NIMS, industry math experts, professors and graduate school students, participated to solve the industrial problem. In addition, the workshop was attended by Osamu Saeki, director of the Institute of Mathematics for Industry(IMI) at Kyushu University in Japan. NIMS discussed future cooperation with IMI.
2018-12-24