Publications

67. Jeonghyee Kim, Suyoung Lee, Woojun Kim*, and Youngchul Sung*, “Decision convformer: Local filtering in metaformer is sufficient for decision making,” accepted to International Conference on Learning Representations  (ICLR) , May 2024 

66. Woojun Kim+, Yongjae Shin+, Jongeui Park, and Youngchul Sung*, "Sample-efficient and safe deep reinforcement learning via reset deep ensemble agents," Conference on Neural Information Processing Systems  (NeurIPS ), New Orleans, LA, Dec. 2023 (+Equal contribution)

65. Sungho Choi, Seungyul Han*, Woojun Kim, Jongseong Chae, Whiyoung Jung, and Youngchul Sung, "Domain adaptive imitation learning with visual observation," Conference on Neural Information Processing Systems  (NeurIPS ), New Orleans, LA, Dec. 2023

64. Suyoung Lee, Myungsik Cho, and Youngchul Sung*, "Parameterizing Non-Parametric Meta-Reinforcement Learning Tasks via Subtask Decomposition, Conference on Neural Information Processing Systems  (NeurIPS ), New Orleans, LA, Dec. 2023

63. Song Noh, Kyungsik Seo, Youngchul Sung, David Love, Junse Lee* and Heejung Yu*, "Joint direct and indirect channel estimation for RIS-assisted millimeter-wave systems based on array signal processing," IEEE Transactions on Wireless Communications, vol. 22, no. 11, pp. 8378 - 8391, Nov. 2023

62. Woojun Kim+, Jeonghye Kim+ and Youngchul Sung*, "LESSON: Learning to integrate exploration strategies for reinforcement learning via an option framework," International Conference on Machine Learning (ICML), Hawaii, HI, Jul. 2023 (+Equal contribution)

61. Woojun Kim and Youngchul Sung*, "An adaptive entropy regularization framework for multi-agent reinforcement learning," International Conference on Machine Learning (ICML), Hawaii, HI, Jul. 2023

60. M. Shahjalal, W. Kim, W. Khalid, S. Moon, M. Khan, S. Liu, S. Lim, E. Kim, D. Yun, J. Lee, W. Lee, S. Hwang, D. Kim, J. Lee, H. Yu, Y. Sung, and Y. Jang*, "Enabling technologies for AI empowered 6G massive radio access networks," ICT Express, vol. 9, no. 3, pp. 341 - 355, Jun. 2023

59. Whiyoung Jung, Myungsik Cho, Jongeui Park and Youngchul Sung*, "Quantile constrained reinforcement learning: A reinforcement learning framework constraining outage probability,"  Conference on Neural Information Processing Systems  (NeurIPS ) 2022,  New Orleans, LA, Nov. 2022

58.  Jongseong Chae, Seungyul Han*, Whiyoung Jung, Myungsik Cho, Sungho Choi, and Youngchul Sung, “Robust imitation learning against variations in environment dynamics,” International Conference on Machine Learning (ICML) 2022, Baltimore, MD, Jul. 2022

57. Jeewon Jeon, Woojun Kim*, Whiyoung Jung and Youngchul Sung*, “MASER: Multi-Agent reinforcementlearning with Subgoals generated from Experience Replay buffer,” International Conference on Machine Learning (ICML) 2022, Baltimore, MD, Jul. 2022

56. Song Noh, Junse Lee, Gilwon Lee, Kyungsik Seo, Youngchul Sung and Heejung Yu*, "Channel Estimation Techniques for RIS-Assisted Communication: Millimeter-Wave and Sub-THz Systems ," IEEE Vehicular Technology Magazine, vol. 17, no. 2, pp. 64 - 73, Jun. 2022

55. Song Noh, Heejung Yu, and Youngchul Sung*, "Training signal design for sparse channel estimation in intelligent reflecting surface-assisted millimeter-wave communication," IEEE  Transactions on Wireless Communications, vol. 21, no. 4, pp. 2399 - 2413, Apr. 2022

54. Giseung Park, Sungho Choi and Youngchul Sung*, "Blockwise sequential model learning for partially observable reinforcement learning," the 36rd AAAI Conference on Artificial Intelligence (AAAI ) 2022,  Vancouver, Canada, Feb. 2022  (Selected as oral presentation)

53. Seungyul Han and Youngchul Sung*, "A max-min entropy framework for reinforcement learning," Conference on Neural Information Processing Systems (NeurIPS) 2021, Dec. 2021

52. Seungyul Han and Youngchul Sung*, "Diversity Actor-Critic: Sample-Aware Entropy Regularization for Sample-Efficient Exploration," International Conference on Machine Learning (ICML) 2021,  Jul. 2021

51. Woonjun Kim, Jongeui Park, and Youngchul Sung*, "Communication in multi-agent reinforcement learning: Intention sharing," International Conference on Learning Representations (ICLR) 2021, May 2021

50. Song Noh, Jiho Song, and Youngchul Sung*, "Fast beam search and refinement for millimeter-wave massive MIMO based on two-level phased arrays," IEEE Transactions on Wireless Communications, vol. 19, no. 10, pp. 6737 - 6751, Oct. 2020

49. Whiyoung Jung, Giseung Park, and Youngchul Sung*, "Population-Guided Parallel Policy Search for Reinforcement Learning," International Conference on Learning Representations (ICLR) 2020, Vienna, Austria, May 2020 

48. Seungyul Han and Youngchul Sung*, "Dimension-Wise Importance Sampling Weight Clipping for Sample-Efficient Reinforcement Learning," International Conference on Machine Learning (ICML) 2019, Long Beach, CA, USA, Jun. 2019

47. Junyeong Seo, Youngchul Sung*, and Hamid Jafarkhani, "A high-diversity transceiver design for MISO broadcast channels," IEEE Transactions on Wireless Communications, vol. 18, no. 5, pp. 2591 - 2606, May 2019

46. Jihoon Chung et al., “5G K-simulink: Development of open-source modular link-level simulator for 5G NSA,” The Journal of Korean Institute of Communications and Information Sciences, vol. 44, no. 3, pp. 602 – 608, Mar. 2019

45. Woojun Kim, Myungsik Cho, and Youngchul Sung*, "Message-dropout: An efficient training method for multi-agent deep reinforcement learning," the  33rd AAAI Conference on Artificial Intelligence (AAAI ) 2019, Honolulu, Hawaii, Jan. 2019

44. Junyeong Seo and Youngchul Sung*, "Beam design and user scheduling for non-orthogonal multiple access with multiple antennas based on Pareto-optimality" IEEE Transactions on Signal Processing, vol. 66, no. 11, pp. 2876 - 2891, Jun. 2018

43. Gilwon Lee and Youngchul Sung*, "A new approach to user scheduling in massive multi-user MIMO broadcast channels," IEEE Transactions on Communications, vol. 66, no. 4, pp. 1481 – 1495, Apr. 2018 

42. Seungyul Han, Youngchul Sung*, and Yong H. Lee, "Filter design for generalized frequency-division multiplexing," IEEE Transactions on Signal Processing, vol. 65, no. 7, pp. 1644 - 1659, Apr. 2017

41. Jungho So and Youngchul Sung*, "Improving non-orthogonal multiple access by forming relaying broadcast channels," IEEE Communications Letters, vol. 20, no. 9, pp. 1816 - 1819, Sep. 2016. An extended version is available at arXiv.

40. Youngchul Sung*, “An introduction to multiple access in wireless communications,” KICS Information and Communication Magazine – Open Lecture Series, vol. 33, no. 6, pp. 10 – 17, Jun. 2016 (an invited article)

39. Jihoon Chung, Donggun Kim, and Youngchul Sung*, “Design of amplify-and-forward helper stations for cellular networks with device-to-device links,” The Journal of Korean Institute of Communications and Information Sciences, vol. 41, no. 5, pp. 539 – 545, May 2016

38. Gilwon Lee, Youngchul Sung*, and Marios Kountouris, "On the performance of random beamforming in sparse millimeter wave channels," IEEE Journal of Selected Topics in Signal Processing, vol. 10, no. 3, pp. 560 - 575, Apr. 2016

37. Junyeong Seo, Youngchul Sung*, Gilwon Lee, and Donggun Kim, "Training beam sequence design for millimeter-wave MIMO systems: A POMDP framework," IEEE Transactions on Signal Processing, vol. 64, no. 5, pp. 1228 - 1242, Mar. 2016

36. Gilwon Lee, Youngchul Sung*, and Junyeong Seo, "Randomly-directional beamforming in mm-wave multi-user MISO downlink," IEEE Transactions on Wireless Communications, vol. 15, no. 2, pp. 1086 - 1100, Feb. 2016

35. Gilwon Lee, Youngchul Sung*, Jungho So, and Junyeong Seo, “Research trends for realization of 5G massive MIMO,” The Magazine of the IEEK, vol. 42, no. 10, pp. 16 - 34, Oct. 2015 (an invited article)

34. Donggun Kim, Gilwon Lee, and Youngchul Sung*, "Two-stage beamformer design for massive MIMO downlink by trace quotient formulation," IEEE Transactions on Communications, vol. 63, no. 6, pp. 2200- 2211, Jun. 2015

33. Jungho So, Donggun Kim, Yuni Lee, and Youngchul Sung*, "Pilot signal design for massive MIMO systems: A received signal-to-noise-ratio-based approach," IEEE Signal Processing Letters, vol. 52, no. 5, pp. 549 - 553, May 2015

32. Song Noh, Youngchul Sung*, and Michael Zoltowski, "A new precoder design for blind channel estimation in MIMO-OFDM systems," IEEE Transactions on Wireless Communications, vol. 13, no. 12, pp. 7011-7024, Dec. 2014

31. Song Noh, Michael Zoltowski, Youngchul Sung*, and David Love "Pilot beam pattern design for channel estimation in massive MIMO systems," IEEE Journal of Selected Topics in Signal Processing, vol. 8, no. 5, pp. 787 - 801, Oct. 2014

30. Donggun Kim, Youngchul Sung*, and Jihoon Chung, "Filter-and-forward relay design for MIMO-OFDM systems," IEEE Transactions on Communications, vol. 62, no. 7, pp. 2329 - 2339, Jul. 2014. Proof of Lemma 1

29. Junse Lee, Heejung Yu and Youngchul Sung*, "Beam tracking for interference alignment in time-varying MIMO interference channels: A conjugate gradient based approach," IEEE Transactions on Vehicular Technology, vol. 63, no. 2, pp. 958 - 964, Feb. 2014

28. Juho Park and Youngchul Sung*, "On the Pareto-optimal beam structure and design for multi-user MIMO interference channels," IEEE Transactions on Signal Processing, vol. 61, no. 23, pp. 5932 - 5946, Dec. 2013

27. Donggun Kim, Junyeong Seo and Youngchul Sung*, "Filter-and-forward transparent relay design for OFDM systems," IEEE Transactions on Vehicular Technology , vol. 62, no. 9, pp. 4392-4407, Nov. 2013.

26. Yingbo Yua*, Daniel W. Bliss, Saeed Gazor, Yue Rong, and Youngchul Sung, "Guest Editorial: Theories and methods for advanced wireless relays - Issue II" IEEE Journal on Selected Areas in Communications, vol. 31, no. 8, pp. 1361 - 1367, Aug. 2013

25. Juho Park, Gilwon Lee, Youngchul Sung* and Masahiro Yukawa, "Coordinated beamforming with relaxed zero forcing: The sequential orthogonal projection combining method and rate control," IEEE Transactions on Signal Processing, vol. 61, no. 12, pp. 3100 - 3112, Jun. 2013

24. Masahiro Yukawa, Youngchul Sung* and Gilwon Lee, "Dual-domain adaptive beamformer under linearly and quadratically constrained minimum variance," IEEE Transactions on Signal Processing, vol. 61, no. 11, pp. 2874 - 2886, Jun. 2013

23. Heejung Yu, Juho Park, Youngchul Sung*, and Yong H. Lee, “Research trends in interference alignment for multi-user interference channels,” The Magazine of the IEEK, vol. 40, no. 4, pp. 54 – 66, Apr. 2013 (an invited article)

22. Yuni Lee and Youngchul Sung*, "Generalized Chernoff information for mismatched Bayesian detection and its application to energy detection," IEEE Signal Processing Letters, vol. 19, no. 11, pp. 753 - 756, Nov. 2012

21. Juho Park, Youngchul Sung*, Donggun Kim and H. Vincent Poor, "Outage probability and outage-based robust beamforming for MIMO interference channels with imperfect channel state information," IEEE Transactions on Wireless Communications, vol. 11, no. 10, pp. 3561 - 3573, Oct. 2012. ( A technical report related to the paper regarding series expansion of Gaussian quadratic forms is also available.)

20. Yingbo Yua*, Daniel W. Bliss, Saeed Gazor, Yue Rong, and Youngchul Sung, "Guest Editorial: Theories and methods for advanced wireless relays - Issue I," IEEE Journal on Selected Areas in Communications, vol. 30, no. 8, pp. 1297 - 1303, Sep. 2012

19. Cheulsoon Kim, Youngchul Sung* and Yong H. Lee, "A joint time-invariant filtering approach to the linear Gaussian relay problem," IEEE Transactions on Signal Processing , vol. 60, no. 8, pp. 4360 - 4375, Aug. 2012. Matlab code

18. Youngchul Sung*, Juho Park, and Donggun Kim, “Trends and advances in multi-cell MISO/MIMO technologies,” KICS Information and Communication Magazine, pp. 11 – 18, Aug. 2012 (an invited article)

17. Haksoo Kim, Heejung Yu, Youngchul Sung* and Yong H. Lee, "An efficient algorithm for zero-forcing coordinated beamforming," IEEE Communications Letters, vol. 16, no. 7, pp. 994 - 997, Jul. 2012

16. Youngseok Oh, Heejung Yu, Yong H. Lee and Youngchul Sung*, "A nonlinear transceiver architecture for overloaded MIMO interference channels," IEEE Transactions on Communications, vol. 60, no. 4, pp. 946 - 951, Apr. 2012

15. Heejung Yu, Youngchul Sung*, Haksoo Kim and Yong H. Lee, "Beam tracking for interference alignment in slowly-fading MIMO interference channels: A perturbations approach under a linear framework," IEEE Transactions on Signal Processing, vol. 60, no. 4, pp. 1910 - 1926, Apr. 2012

14. Heejung Yu and Youngchul Sung*, "Least squares approach to joint beam design for interference alignment in multiuser multi-input multi-output interference channels," IEEE Transactions on Signal Processing, vol. 58, no. 9, pp. 4960 - 4966, Sep. 2010

13. Jo Woon Chong, Dan Keun Sung* and Youngchul Sung, "Cross-layer performance analysis for CSMA/CA protocols: Impact of imperfect sensing," IEEE Transactions on Vehicular Technology, vol. 59, no. 3, pp. 1100 - 1108, Mar. 2010

12. Jo Woon Chong, Youngchul Sung* and Dan Keun Sung, "RawPEACH: Multi-band CSMA/CA-based cognitive radio networks," Journal of Communications and Networks, vol. 11, no. 2, pp. 174 - 185, Apr. 2009

11. Yirang Lim, Juho Park and Youngchul Sung*, "Upper bound for the loss of energy detection of signals in multipath fading channels," IEEE Signal Processing Letters, vol. 16, no. 11, pp. 949 - 952, Nov. 2009

10. Youngchul Sung*, H. Vincent Poor and Heejung Yu, "How much information can one get from a wireless ad hoc sensor network over a correlated random field?," IEEE Transactions on Information Theory, vol. 55, no. 6, pp. 2827 - 2847, Jun. 2009.  Simple Condition for Theorem 2.

9. Youngchul Sung*, Yirang Lim, Lang Tong and Alle-Jan van der Veen, "Signal processing advances for 3G WCDMA: From rake receivers to blind techniques," IEEE Communications Magazine, no. 1, pp. 48 - 54, Jan. 2009

8. Youngchul Sung*, Xin Zhang, Lang Tong and H. Vincent Poor, "Sensor configuration and activation for field detection in large sensor arrays," IEEE Transactions on Signal Processing, vol. 56, no. 2, pp. 447 - 463, Feb. 2008

7. Youngchul Sung*, Saswat Misra, Lang Tong and Anthony Ephremides, "Cooperative routing for distributed detection in large sensor networks," IEEE Journal on Selected Areas in Communications, Vol. 25, no. 2, pp. 471 - 483, Feb. 2007

6. Youngchul Sung, Saswat Misra, Lang Tong* and Anthony Ephremides, "Signal processing for application-specific ad-hoc networks," IEEE Signal Processing Magazine, vol. 23, no. 5, pp. 74 - 83, Sep. 2006

5. Youngchul Sung, Lang Tong* and H. Vincent Poor, "Neyman-Pearson detection of Gauss-Markov signals in noise: Closed-form error exponent and properties," IEEE Transactions on Information Theory, vol. 52, no. 4, pp. 1354-1365, Apr. 2006. (This paper's conference version won ICASSP 2005 Paper Award.)

4. Youngchul Sung, Lang Tong* and Ananthram Swami, "Asymptotic locally optimal detector for large scale sensor networks under the Poisson regime," IEEE Transactions on Signal Processing, vol. 53, no. 6, pp. 2005 - 2017, Jun. 2005

3. Youngchul Sung, Lang Tong* and Ananthram Swami, "Blind channel estimation for space-time coded WCDMA," EURASIP Journal on Wireless Communications and Networking, vol. 2004, no. 2, pp. 322-334, Dec. 2004

2. Youngchul Sung and Lang Tong*, "Tracking of fast-fading channels in long code CDMA," IEEE Transactions on Signal Processing, vol. 52, no.3, pp. 786-795, Mar. 2004

1. Lang Tong*, Alle-Jan van der Veen, Patrick Dewilde and Youngchul Sung, "Blind decorrelating RAKE receiver for long code WCDMA," IEEE Transactions on Signal Processing, vol. 51, no. 6, pp.1642-1655, Jun. 2003

(Asterisks denote corresponding authors.)