About

Dr. Mei-Ling Ting Lee is a Professor in the Department of Epidemiology & Biostatistics at the University of Maryland, College Park. Her research focuses on models for time-to-event data, analysis of genomic data, statistical distributional theory and applications, nonparametric methods, and statistical applications in epidemiology and medical research. She developed a statistical model called the first hitting-time based threshold regression (TR) for analyzing survival data, which has been extended to machine learning neural networks for AI applications. Dr. Lee is the Founding Editor and Editor-in-Chief of the international journal Lifetime Data Analysis, which emphasizes methods for analyzing time-to-event data. She has published over 150 articles, including a widely used monograph titled 'Analysis of Microarray Gene Expression Data' in 2004, which includes sample size and power calculations for microarray studies and chapters on machine learning bioinformatics methods. Her extensive experience includes analyzing large-scale high-dimensional genomic data, and her work has significantly contributed to the fields of biostatistics and bioinformatics.

Research topics

• Nuclear physics
• Astronomy
• Physics
• Astrophysics

Selected publications

• Development of MMC-based lithium molybdate cryogenic calorimeters for AMoRE-II

  The European Physical Journal C · 2025-02-11 · 2 citations

  articleOpen access

  Abstract The AMoRE collaboration searches for neutrinoless double beta decay of $$^{100}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mn>100</mml:mn> </mml:mmultiscripts> </mml:math> Mo using molybdate scintillating crystals via low temperature thermal calorimetric detection. The early phases of the experiment, AMoRE-pilot and AMoRE-I, have demonstrated competitive discovery potential. Presently, the AMoRE-II experiment, featuring a large detector array with about 90 kg of $$^{100}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mn>100</mml:mn> </mml:mmultiscripts> </mml:math> Mo isotope, is under construction. This paper discusses the baseline design and characterization of the lithium molybdate cryogenic calorimeters to be used in the AMoRE-II detector modules. The results from prototype setups that incorporate new housing structures and two different crystal masses (316 g and 517–521 g), operated at 10 mK temperature, show energy resolutions (FWHM) of 7.55–8.82 keV at the 2.615 MeV $$^{208}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mn>208</mml:mn> </mml:mmultiscripts> </mml:math> Tl $$\gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>γ</mml:mi> </mml:math> line and effective light detection of 0.79–0.96 keV/MeV. The simultaneous heat and light detection enables clear separation of alpha particles with a discrimination power of 12.37–19.50 at the energy region around $$^{6}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mmultiscripts> <mml:mrow/> <mml:mrow/> <mml:mn>6</mml:mn> </mml:mmultiscripts> </mml:math> Li $$(n,\alpha )^3$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow> <mml:mo>(</mml:mo> <mml:mi>n</mml:mi> <mml:mo>,</mml:mo> <mml:mi>α</mml:mi> <mml:mo>)</mml:mo> </mml:mrow> <mml:mn>3</mml:mn> </mml:msup> </mml:math> H with Q-value = 4.785 MeV. Promising detector performances were demonstrated at temperatures as high as 30 mK, which relaxes the temperature constraints for operating the large AMoRE-II array.

  PublisherOA PDFDOI

• Combined Annual Modulation Dark Matter Search with COSINE-100 and ANAIS-112

  Physical Review Letters · 2025-09-17 · 7 citations

  articleOpen access

  The annual modulation signal, claimed to be consistent with dark matter as observed by DAMA/LIBRA in a sodium-iodide based detector, has persisted for over two decades. COSINE-100 and ANAIS-112 were designed to test the claim directly using the same target material. COSINE-100, located at Yangyang Underground Laboratory in South Korea, and ANAIS-112, located at Canfranc Underground Laboratory in Spain, have been taking data since 2016 and 2017, respectively. Each experiment published its respective results independently. In this Letter, we present the results of an annual modulation search as a test of the signal observed by DAMA/LIBRA with the first three respective years of data from COSINE-100 and ANAIS-112. Using a Markov Chain Monte Carlo method, we find best fit values for modulation amplitude of -0.0002±0.0026 cpd/kg/keV in the 1-6 keV and 0.0021±0.0028 cpd/kg/keV in the 2-6 keV energy regions. These results are not compatible with DAMA/LIBRA's assertion for their observation of annual modulation at 3.7σ and 2.6σ, respectively. Performing a simple combination of the newly released 6-year datasets from both experiments finds values consistent with no modulation at 0.0005±0.0019 cpd/kg/keV in the 1-6 keV and 0.0027±0.0021 cpd/kg/keV in the 2-6 keV energy regions with 4.7σ and 3.5σ respective exclusions of the DAMA/LIBRA signal.

  PublisherOA PDFDOI

• Dual TCR T Cells in the Acute Rejection Heterotopic Transplant Model

  American Journal of Transplantation · 2025-08-01

  article1st authorCorresponding
  PublisherDOI

• Efficient Time-Frequency Representations for Real-Time Deep Learning-Based Classification of LPI Radar Signal

  Journal of the Korea Academia-Industrial cooperation Society · 2025-08-31

  articleOpen access1st authorCorresponding

  본 연구는 저피탐(Low Probability of Intercept, LPI) 레이다 신호의 실시간 분석을 위해 최신 딥러닝 분류 모델에 적합한 시간 주파수 표현 기법의 적용 방안을 탐색한다. 최근의 연구에 따르면, CWD(Choi-Williams Distribution)는 STFT(Short-Time Fourier Transform)에 비해 더 정확한 시간 주파수 이미지를 생성하여 우수한 분류 성능을 제공한다. 그러나 CWD는 계산 복잡도가 높아 실시간 레이다 시스템에 적용하기에는 한계가 있다. 본 연구는 이를 극복하기 위해 계산 효율이 높은 STFT 기반의 접근 방식을 채택하고, ResNet 및 Vision Transformer와 같은 최신 딥러닝 모델에 적합하도록 구조와 파라미터를 최적화하여, CWD에 필적하는 성능을 달성할 수 있는 가능성을 탐색하였다. 먼저 두 기법 간의 이론적 계산 복잡도를 분석하고, 이를 바탕으로 시뮬레이션을 통해 분류 성능을 평가하였다. 그 결과, 기존 CNN 기반 모델에서는 CWD가 우수한 성능을 보였지만, ResNet과 Vision Transformer와 같은 최신 모델에서는 특히 낮은 신호 대 잡음비(SNR) 조건에서 오히려 STFT가 더 뛰어난 성능을 제공함을 확인하였다. 본 연구는 효율성이 뛰어난 STFT 기반 기법이 실시간 LPI 레이다 신호 처리에 적용될 경우, 성능과 효율성을 동시에 향상시킬 수 있음을 제안한다.

  PublisherDOI

• Luminescence and Scintillation Properties of NaI:In Crystal

  IEEE Transactions on Nuclear Science · 2025-03-05 · 2 citations

  article

  Single crystals of NaI activated with 0.02, 0.05, 0.1, and 0.5 mol% indium (In) have been grown with a two-zone vertical Bridgman furnace. The luminescence measurement of the crystals is carried out under the excitation of X-rays and photoluminescence (PL). Under X-ray excitation, the emission has broad bands peaking at 450 and 535 nm. The maximum radioluminescence of the crystal is obtained for NaI:0.1 mol% In. The pulse height spectra of the crystals are measured under 662 keV <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\gamma $ </tex-math></inline-formula>-rays excitation from a Cs-137 source. The absolute light yields of the crystals are calculated by comparing the 662 keV <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\gamma $ </tex-math></inline-formula>-rays photopeak with that measured for reference CsI:Tl and the indium-doped NaI crystals. The maximum light yield of ~42000 photons/MeV is found for NaI:0.5 mol% In.

  PublisherDOI

• Improved Limit on Neutrinoless Double Beta Decay of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Mo</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>100</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math> from AMoRE-I

  Physical Review Letters · 2025-02-27 · 22 citations

  article

  AMoRE searches for the neutrinoless double beta decay using 100 kg of enriched ^{100}Mo. Scintillating molybdate crystals coupled with a metallic magnetic calorimeter operate at milli-Kelvin temperatures to measure the energy of electrons emitted in the decay. AMoRE-I is a demonstrator for the full-scale AMoRE, operated at the Yangyang Underground Laboratory for over two years. The exposure was 8.02 kg year (or 3.89 kg_{^{100}Mo} year), and the total background rate near the Q value was 0.025±0.002 counts/keV/kg/year. We observed no indication of 0νββ decay and report a new lower limit of the half-life of ^{100}Mo 0νββ decay as T_{1/2}^{0ν}>2.9×10^{24} yr at 90% confidence level. The effective Majorana mass limit range is m_{ββ}<(210-610) meV using nuclear matrix elements estimated in the framework of different models, including the recent shell model calculations.

  PublisherDOI

• Long-Term Oncologic Outcome of Breast-Conserving Treatment in Patients With Breast Cancer With <i>BRCA </i>Variants

  JAMA Network Open · 2025-05-14 · 4 citations

  articleOpen access

  Importance: Patients with sporadic breast cancer have comparable prognoses after undergoing either breast-conserving treatment (BCT) or mastectomy. However, there are limited and inconsistent data on the assessment of oncologic outcomes between BCT and mastectomy in patients with pathogenic variants in BRCA1 or BRCA2. Objective: To investigate the outcomes of BCT on recurrence and survival in patients with breast cancer with BRCA1 or BRCA2 pathogenic variants. Design, Setting, and Participants: This retrospective multicenter cohort study analyzed patients from 13 institutions in South Korea with primary breast cancer with BRCA1 or BRCA2 pathogenic variants who underwent either BCT or mastectomy from January 2008 through December 2015. The median (IQR) follow-up period was 8.3 (6.4-9.6) years. Data were analyzed from September 2023 to August 2024. Exposure: BRCA1 or BRCA2 pathogenic variant and BCT. Main Outcomes and Measures: Primary outcomes were logoregional recurrence-free survival, distant recurrence-free survival, and overall survival. Propensity score matching (PSM) using the greedy nearest neighbor method was performed to match covariates to minimize potential selection bias. Results: A total of 575 female patients with BRCA1 or BRCA2 pathogenic variants were identified, all of whom were South Korean with a mean (SD) age of 42.0 (9.7) years. Among them, 367 patients (66.2%) received BCT and 186 (33.8%) were treated with mastectomy. BCT was not a factor associated with oncologic outcomes, including locoregional recurrence, compared with mastectomy. After adjusting for clinicopathologic characteristics through 1:1 PSM, there were still no statistically significant differences in oncologic outcomes between the BCT group and the mastectomy group. Multivariate analysis showed that the type of breast surgery was not significantly associated with oncologic outcomes. In subgroup analysis among matched patients based on BRCA1 or BRCA2 status, tumor size, lymph node metastasis, histologic grade, and subtype, BCT was also not a factor associated with risk for recurrence. Conclusions and Relevance: The findings from this cohort study of patients with BRCA1 or BRCA2 pathogenic variants suggested that there were no significant differences in oncologic outcomes between patients who underwent BCT and those who underwent mastectomy. Therefore, breast conservation with close surveillance can be considered a viable treatment option for BRCA1 or BRCA2 pathogenic variant carriers. Further studies incorporating prospectively collected data are warranted to validate our findings.

  PublisherDOI

• Abstract P1-06-09: Importance of Assessing Thyroid Dysfunction in Breast Cancer Patients Undergoing Pembrolizumab-based Neoadjuvant Chemotherapy

  Clinical Cancer Research · 2025-06-13

  article

  Abstract Introduction: Pembrolizumab is a novel immunotherapy agent that improves oncological outcomes in various cancer types. Although there are minor immune-related adverse events (irAEs) when used alone, various irAEs have been reported when it is combined with chemotherapy. The aims of this study were to investigate irAEs that occurred after neoadjuvant chemotherapy (NAC) with pembrolizumab based on the KEYNOTE-522 regimen for triple-negative breast cancer (TNBC) and to identify fatal irAEs that should be corrected before surgery under general anesthesia. Methods: Between 2022 and 2024, a total of, 71 cases from 81 patients who completed NAC with pembrolizumab based on KEYNOTE-522 regimen (wP/Cab and pembrolizumab followed by AC and pembrolizumab) followed by surgery were reviewed based on their medical records. All irAEs that occurred were investigated and classified into five categories: systemic, gastrointestinal, respiratory, musculoskeletal, and endocrine. Underlying diseases that existed before the diagnosis of breast cancer or complications that occurred after surgery were excluded. Results: The mean age of the patients was 49.62 (SD, ±10.6) years, and the stages at diagnosis were as follows: IIA (n=23, 32.4%), IIB (n=22, 31.0%), IIIA (n=14, 16.2%), IIIB (n=1, 1.4%), and IIIC (n=11, 15.5%). After NAC with pembrolizumab, the pCR rate was 49.3% (35/71) Fifty-three patients (62.2%) experienced adverse events, and the number of adverse events were as follows: 1 (n=11, 20.8%), 2 (n=20, 37.7%), and ≥3 (n=22, 41.5%). Gastrointestinal symptoms were the most common (n=46, 86.8%), and dermatologic symptoms were the second most common (n=31, 58.5%). Among fatal irAEs, including colitis and pneumonitis, they occurred in 11 patients (20.8%) and 2 patients (3.8%), respectively. There was no case of hepatitis, myocarditis, or hypophysitis as fatal irAEs after NAC and pembrolizumab for TNBC. Among these irAEs, thyroid disorders (n=16, 22.5%) were the most common adverse event after skin rash and nausea. Of the patients with thyroid disorders, 3 experienced fatal dysfunction. Their surgeries were delayed for an average of 8.5 weeks to correct the thyroid imbalance before they could safely undergo general anesthesia. The remaining patients, who did not experience such complications, were able to undergo surgery after an average of 5.2 weeks. Conclusion: The irAEs that occurred after NAC with pembrolizumab in TNBC were varied and included some that were severe enough to affect the timing of surgery under general anesthesia. Thyroid dysfunction, in particular, should be evaluated and corrected during the neoadjuvant chemotherapy to prevent delays in surgery. Citation Format: Byeongju Kang, Jung Eun Choi, Moohyun Lee, Ho Yong Park, Jin Hyang Jung, Soo Jung Lee, Su Hwan Kang, Jin Gu Kang, Sun Hee Kang, Jihyoung Cho, Yee Soo Chae, Soo Jung Lee, In-Hee Lee, Keon Uk Park, Hyera Kim, Jeeyeon Lee. Importance of Assessing Thyroid Dysfunction in Breast Cancer Patients Undergoing Pembrolizumab-based Neoadjuvant Chemotherapy [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2024; 2024 Dec 10-13; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2025;31(12 Suppl):Abstract nr P1-06-09.

  PublisherDOI

• Publisher Erratum: Development of MMC-based lithium molybdate cryogenic calorimeters for AMoRE-II

  The European Physical Journal C · 2025-03-10

  articleOpen access
  PublisherOA PDFDOI

• COSINE-100 full dataset challenges the annual modulation signal of DAMA/LIBRA

  Science Advances · 2025-09-03 · 5 citations

  articleOpen access

  For over 25 years, the DAMA/LIBRA collaboration has claimed to observe an annual modulation signal, suggesting the existence of dark matter interactions. However, no experiment using different target materials has observed a dark matter signal consistent with their result. To address this puzzle, the COSINE-100 collaboration conducted a model-independent test using sodium iodide crystal detectors, the same target material as DAMA/LIBRA. Analyzing data collected over 6.4 years by the effective mass of 61.3 kilograms, with improved energy calibration and time-dependent background modeling, we found no evidence of an annual modulation signal, challenging the DAMA/LIBRA result with a confidence level greater than 3σ. This finding represents a substantial step toward resolving the long-standing debate surrounding DAMA/LIBRA's dark matter claim, indicating that the observed modulation is unlikely to be caused by dark matter interactions.

  PublisherDOI

Frequent coauthors

• E. S. Seo

  University of Maryland, College Park

  591 shared

• N. Picot-Clémente

  Kyungpook National University

  471 shared

• Y. S. Yoon

  Korea Research Institute of Standards and Science

  465 shared

• L. Lutz

  Goethe University Frankfurt

  451 shared

• H. J. Kim

  419 shared

• M. Copley

  University of Maryland, College Park

  386 shared

• D. Angelaszek

  University of Maryland, College Park

  384 shared

• J. H. Han

  University of Seoul

  380 shared

Education

• Doctor of Science, Physics

  Korea University

  1992

• Master of Science, Physics

  Korea University

  1988

• Bachelor of Science, Physics

  Korea University

  1986

Awards & honors

• Elected Member, International Statistical Institute, the Net…
• Elected Fellow, Royal Statistical Society, United Kingdom (1…
• Elected Fellow, American Statistical Association, USA (1999)
• Elected Fellow, Institute of Mathematical Statistics, USA (2…
• Mosteller Statistician of the Year, American Statistical Ass…