Publications

Journal Publications

J48. Kai Wan, Xin Yao, Hua Sun, Mingyue Ji, Giuseppe Caire, On the Information Theoretic Secure Aggregation with Uncoded Groupwise Keys, IEEE Transactions on Information Theory, Vol. 70, No. 9, Pages: 6596-6619, September 2024.

J47. Zhou Li, Hua Sun, On Extremal Rates of Storage over Graphs, IEEE Transactions on Information Theory, Vol. 70, No. 4, Pages: 2464-2478, April 2024.

J46. Yizhou Zhao, Hua Sun, Secure Summation: Capacity Region, Groupwise Key, and Feasibility, IEEE Transactions on Information Theory, Vol. 70, No. 2, Pages: 1376-1387, February 2024.

J45. Ali Gholami, Kai Wan, Hua Sun, Mingyue Ji, Giuseppe Caire, Coded Caching With Private Demands and Caches, IEEE Transactions on Information Theory, Vol. 70, No. 2, Pages: 1087-1106, February 2024.

J44. Zhou Li, Hua Sun, On the Linear Capacity of Conditional Disclosure of Secrets, IEEE Transactions on Communications, Vol. 71, No. 12, Pages: 7218-7227, December 2023.

J43. Zhou Li, Hua Sun, On Extremal Rates of Secure Storage over Graphs, IEEE Transactions on Information Forensics and Security, Vol. 18, Pages: 4721-4731, 2023.

J42. Chao Tian, Hua Sun, Jun Chen, A Shannon-Theoretic Approach to the Storage–Retrieval Trade-Off in PIR Systems, Information, Vol. 14, No. 1: 44, January 2023 (Invited Paper).

J41. Hua Sun, Compound Secure Groupcast: Key Assignment for Selected Broadcasting, IEEE Journal on Selected Areas in Information Theory, Vol. 3, No. 2, Pages: 379-389, June 2022.

J40. Ruida Zhou, Chao Tian, Hua Sun, James Plank, Two-Level Private Information Retrieval, IEEE Journal on Selected Areas in Information Theory, Vol. 3, No. 2, Pages: 337-349, June 2022.

J39. Yizhou Zhao, Hua Sun, Information Theoretic Secure Aggregation with User Dropouts, IEEE Transactions on Information Theory, Vol. 68, No. 11, Pages: 7471-7484, November 2022.

J38. Kai Wan, Hua Sun, Mingyue Ji, Daniela Tuninetti, Giuseppe Caire, On the Fundamental Limits of Device-to-Device Private Caching Under Uncoded Cache Placement and User Collusion, IEEE Transactions on Information Theory, Vol. 68, No. 9, Pages: 5701-5729, September 2022.

J37. Hua Sun, Secure Groupcast with Shared Keys, IEEE Transactions on Information Theory, Vol. 68, No. 7, Pages: 4681-4699, July 2022.

J36. Kai Wan, Hua Sun, Mingyue Ji, Daniela Tuninetti, Giuseppe Caire, Cache-Aided Matrix Multiplication Retrieval, IEEE Transactions on Information Theory, Vol. 68, No. 7, Pages: 4301-4319, July 2022.

J35. Zhou Li, Hua Sun, Conditional Disclosure of Secrets: A Noise and Signal Alignment Approach, IEEE Transactions on Communications, Vol. 70, No. 6, Pages: 4052-4062, June 2022.

J34. Kai Wan, Hua Sun, Mingyue Ji, Giuseppe Caire, On Secure Distributed Linearly Separable Computation, IEEE Journal on Selected Areas in Communications, Vol. 40, No. 3, Pages: 912-926, March 2022.

J33. Kai Wan, Hua Sun, Mingyue Ji, Giuseppe Caire, Distributed Linearly Separable Computation, IEEE Transactions on Information Theory, Vol. 68, No. 2, Pages: 1259-1278, February 2022.

J32. Chunhua Geng, Hua Sun, Syed A. Jafar, Multilevel Topological Interference Management, IEEE Transactions on Communications, Vol. 69, No. 11, Pages: 7350-7362, November 2021.

J31. Kai Wan, Hua Sun, Mingyue Ji, Giuseppe Caire, On the Tradeoff Between Computation and Communication Costs for Distributed Linearly Separable Computation, IEEE Transactions on Communications, Vol. 69, No. 11, Pages: 7390-7405, November 2021.

J30. Yizhou Zhao, Hua Sun, Expand-and-Randomize: An Algebraic Approach to Secure Computation, Entropy, Vol. 23, No. 11: 1461, November 2021.

J29. Xiang Zhang, Kai Wan, Hua Sun, Mingyue Ji, Giuseppe Caire, On the Fundamental Limits of Cache-aided Multiuser Private Information Retrieval, IEEE Transactions on Communications, Vol. 69, No. 9, Pages: 5828-5842, September 2021.

J28. Kai Wan, Hua Sun, Mingyue Ji, Daniela Tuninetti, Giuseppe Caire, On the Optimal Load-Memory Tradeoff of Cache-Aided Scalar Linear Function Retrieval, IEEE Transactions on Information Theory, Vol. 67, No. 6, Pages: 4001-4018, June 2021.

J27. Kai Wan, Hua Sun, Mingyue Ji, Daniela Tuninetti, Giuseppe Caire, Cache-Aided General Linear Function Retrieval, Entropy, Vol. 23, No. 1: 25, January 2021 (Invited Paper).

J26. Hua Sun, Private Information Delivery, IEEE Transactions on Information Theory, Vol. 66, No. 12, Pages: 7672-7683, December 2020.

J25. Hua Sun, Syed A. Jafar, On the Capacity of Locally Decodable Codes, IEEE Transactions on Information Theory, Vol. 66, No. 10, Pages: 6566-6579, October 2020.

J24. Ruida Zhou, Chao Tian, Hua Sun, Tie Liu, Capacity-Achieving Private Information Retrieval Codes from MDS-Coded Databases with Minimum Message Size, IEEE Transactions on Information Theory, Vol. 66, No. 8, Pages: 4904-4916, August 2020. (2020-2021 IEEE Data Storage Best Student Paper Award).

J23. Hua Sun, Syed A. Jafar, On the Capacity of Computation Broadcast, IEEE Transactions on Information Theory, Vol. 66, No. 6, Pages: 3417-3434, June 2020.

J22. Xinping Yi, Hua Sun, Opportunistic Topological Interference Management, IEEE Transactions on Communications, Vol. 68, No. 1, Pages: 521-535, January 2020.

J21. Xinping Yi, Hua Sun, Opportunistic Treating Interference as Noise, IEEE Transactions on Information Theory, Vol. 66, No. 1, Pages: 520-533, January 2020.

J20. Chao Tian, Hua Sun, Jun Chen, Capacity-Achieving Private Information Retrieval Codes with Optimal Message Size and Upload Cost, IEEE Transactions on Information Theory, Vol. 65, No. 11, Pages: 7613-7627, November 2019.

J19. Zhuqing Jia, Hua Sun, Syed A. Jafar, Cross Subspace Alignment and the Asymptotic Capacity of X-Secure T-Private Information Retrieval, IEEE Transactions on Information Theory, Vol. 65, No. 9, Pages: 5783-5798, September 2019.

J18. Hua Sun, Chao Tian, Breaking the MDS-PIR Capacity Barrier via Joint Storage Coding, Information, Vol. 10, No. 9: 265, September 2019 (Invited Paper).

J17. Hua Sun, The Capacity of Anonymous Communications, IEEE Transactions on Information Theory, Vol. 65, No. 6, Pages: 3871-3879, June 2019.

J16. Hua Sun, Syed A. Jafar, The Capacity of Private Computation, IEEE Transactions on Information Theory, Vol. 65, No. 6, Pages: 3880-3897, June 2019.

J15. Qiwen Wang, Hua Sun, Mikael Skoglund, The Capacity of Private Information Retrieval with Eavesdroppers, IEEE Transactions on Information Theory, Vol. 65, No. 5, Pages: 3198-3214, May 2019.

J14. Hua Sun, Syed A. Jafar, The Capacity of Symmetric Private Information Retrieval, IEEE Transactions on Information Theory, Vol. 65, No. 1, Pages: 322-329, January 2019.

J13. Hua Sun, Syed A. Jafar, Multiround Private Information Retrieval: Capacity and Storage Overhead, IEEE Transactions on Information Theory, Vol. 64, No. 8, Pages: 5743-5754, August 2018.

J12. Hua Sun, Syed A. Jafar, The Capacity of Robust Private Information Retrieval with Colluding Databases, IEEE Transactions on Information Theory, Vol. 64, No. 4, Pages: 2361-2370, April 2018.

J11. Xinping Yi, Hua Sun, Syed A. Jafar, David Gesbert, TDMA is Optimal for All-unicast DoF Region of TIM if and only if Topology is Chordal Bipartite, IEEE Transactions on Information Theory, Vol. 64, No. 3, Pages: 2065-2076, March 2018.

J10. Hua Sun, Syed A. Jafar, Private Information Retrieval from MDS Coded Data with Colluding Servers: Settling a Conjecture by Freij-Hollanti et al., IEEE Transactions on Information Theory, Vol. 64, No. 2, Pages: 1000-1022, February 2018.

J9. Hua Sun, Syed A. Jafar, Optimal Download Cost of Private Information Retrieval for Arbitrary Message Length, IEEE Transactions on Information Forensics and Security, Vol. 12, No. 12, Pages: 2920-2932, December 2017.

J8. Bofeng Yuan, Hua Sun, Syed A. Jafar, Replication-based Outer Bounds: On the Optimality of “Half the Cake” for Rank-Deficient MIMO Interference Networks, IEEE Transactions on Information Theory, Vol. 63, No. 10, Pages: 6607-6621, October 2017.

J7. Hua Sun, Syed A. Jafar, The Capacity of Private Information Retrieval, IEEE Transactions on Information Theory, Vol. 63, No. 7, Pages: 4075-4088, July 2017.

J6. Chenwei Wang, Hua Sun, Syed A. Jafar, Genie Chains: Exploring Outer Bounds on the Degrees of Freedom of MIMO Interference Networks, IEEE Transactions on Information Theory, Vol. 62, No. 10, Pages: 5573-5602, October 2016.

J5. Hua Sun, Syed A. Jafar, On the Optimality of Treating Interference as Noise for K-User Parallel Gaussian Interference Networks, IEEE Transactions on Information Theory, Vol. 62, No. 4, Pages: 1911-1930, April 2016.

J4. Hua Sun, Sundar R. Krishnamurthy, Syed A. Jafar, Rank Matching for Multihop Multiflow, IEEE Transactions on Information Theory, Vol. 61, No. 9, Pages: 4751-4764, September 2015.

J3. Chunhua Geng, Hua Sun, Syed A. Jafar, On the Optimality of Treating Interference as Noise: General Message Sets, IEEE Transactions on Information Theory, Vol. 61, No. 7, Pages: 3722-3736, July 2015.

J2. Hua Sun, Syed A. Jafar, Index Coding Capacity: How far can one go with only Shannon Inequalities?, IEEE Transactions on Information Theory, Vol. 61, No. 6, Pages: 3041-3055, June 2015.

J1. Hua Sun, Tiangao Gou, Syed A. Jafar, Degrees of Freedom of MIMO X Networks: Spatial Scale Invariance and One-Sided Decomposability, IEEE Transactions on Information Theory, Vol. 59, No. 12, Pages: 8377-8385, December 2013.

Conference Publications

C54. Kai Wan, Hua Sun, Mingyue Ji, Tiebin Mi, Giuseppe Caire, Optimal Information Theoretic Secure Aggregation with Uncoded Groupwise Keys, Proceedings of IEEE International Symposium on Information Theory (ISIT), Athens, Greece, July 2024.

C53. Ziting Zhang, Jiayu Liu, Kai Wan, Hua Sun, Mingyue Ji, Giuseppe Caire, On the Optimality of Secure Aggregation with Uncoded Groupwise Keys Against User Dropouts and User Collusion, Proceedings of IEEE International Symposium on Information Theory (ISIT), Athens, Greece, July 2024.

C52. Ali Gholami, Kai Wan, Tayyebeh Jahani-Nezhad, Hua Sun, Mingyue Ji, Giuseppe Caire, On Multi-Message Private Computation, Proceedings of IEEE International Symposium on Information Theory (ISIT), Athens, Greece, July 2024.

C51. Xiang Zhang, Kai Wan, Hua Sun, Mingyue Ji, Giuseppe Caire, A Novel Scheme for Cache-Aided Multiuser Private Information Retrieval with User-to-User Privacy, Proceedings of 2023 57th Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, CA, USA, October 2023.

C50. Kai Wan, Yin Yao, Hua Sun, Mingyue Ji, Giuseppe Caire, GroupSecAgg: Information Theoretic Secure Aggregation with Uncoded Groupwise Keys, Proceedings of IEEE International Conference on Communications (ICC), Rome, Italy, June 2023.

C49. Yizhou Zhao, Hua Sun, The Optimal Rate of MDS Variable Generation, Proceedings of IEEE International Symposium on Information Theory (ISIT), Taipei, Taiwan, June 2023.

C48. Zhou Li, Hua Sun, On Extremal Rates of Storage over Graphs, Proceedings of IEEE International Symposium on Information Theory (ISIT), Taipei, Taiwan, June 2023.

C47. Zhou Li, Yizhou Zhao, Hua Sun, Weakly Secure Summation with Colluding Users, Proceedings of IEEE International Symposium on Information Theory (ISIT), Taipei, Taiwan, June 2023.

C46. Wenbo Huang, Kai Wan, Hua Sun, Mingyue Ji, Robert Caiming Qiu, Giuseppe Caire, Fundamental Limits of Distributed Linearly Separable Computation under Cyclic Assignment, Proceedings of IEEE International Symposium on Information Theory (ISIT), Taipei, Taiwan, June 2023.

C45. Ziting Zhang, Kai Wan, Hua Sun, Mingyue Ji, Giuseppe Caire, Secure Aggregation with Uncoded Groupwise Keys Against User Collusion, Proceedings of 2023 8th International Conference on Computer and Communication Systems (ICCCS), Guangzhou, China, April 2023.

C44. Xiang Zhang, Kai Wan, Hua Sun, Mingyue Ji, Giuseppe Caire, Fundamental Limits of Cache-aided Multiuser PIR: The Two-message Two-user Case, Proceedings of IEEE International Symposium on Information Theory (ISIT), Espoo, Finland, June 2022.

C43. Ali Gholami, Kai Wan, Hua Sun, Mingyue Ji, Giuseppe Caire, Coded Caching With Private Demands and Caches, Proceedings of IEEE International Symposium on Information Theory (ISIT), Espoo, Finland, June 2022.

C42. Yizhou Zhao, Hua Sun, Information Theoretic Secure Aggregation with User Dropouts, Proceedings of IEEE International Symposium on Information Theory (ISIT), Melbourne (Virtual), Australia, July 2021.

C41. Zhou Li, Hua Sun, On the Linear Capacity of Conditional Disclosure of Secrets, Proceedings of IEEE International Symposium on Information Theory (ISIT), Melbourne (Virtual), Australia, July 2021.

C40. Hua Sun, Compound Secure Groupcast: Key Assignment for Selected Broadcasting, Proceedings of IEEE International Symposium on Information Theory (ISIT), Melbourne (Virtual), Australia, July 2021.

C39. Ruida Zhou, Chao Tian, Hua Sun, James S. Plank, Two-Level Private Information Retrieval, Proceedings of IEEE International Symposium on Information Theory (ISIT), Melbourne (Virtual), Australia, July 2021.

C38. Kai Wan, Hua Sun, Mingyue Ji, Giuseppe Caire, Secure Distributed Linearly Separable Computation, Proceedings of IEEE International Symposium on Information Theory (ISIT), Melbourne (Virtual), Australia, July 2021.

C37. Xiang Zhang, Kai Wan, Hua Sun, Mingyue Ji, Giuseppe Caire, A New Design of Cache-aided Multiuser Private Information Retrieval with Uncoded Prefetching, Proceedings of IEEE International Symposium on Information Theory (ISIT), Melbourne (Virtual), Australia, July 2021.

C36. Kai Wan, Hua Sun, Mingyue Ji, Daniela Tuninetti, Giuseppe Caire, Cache-Aided Matrix Multiplication Retrieval, Proceedings of IEEE International Symposium on Information Theory (ISIT), Melbourne (Virtual), Australia, July 2021.

C35. Zhou Li, Hua Sun, Conditional Disclosure of Secrets: A Noise and Signal Alignment Approach, Proceedings of IEEE International Symposium on Information Theory (ISIT), Los Angeles (Virtual), California, USA, June 2020.

C34. Yanliang Zhou, Qiwen Wang, Hua Sun, Shengli Fu, The Minimum Upload Cost of Symmetric Private Information Retrieval, Proceedings of IEEE International Symposium on Information Theory (ISIT), Los Angeles (Virtual), California, USA, June 2020.

C33. Xiang Zhang, Kai Wan, Hua Sun, Mingyue Ji, Cache-aided Multiuser Private Information Retrieval, Proceedings of IEEE International Symposium on Information Theory (ISIT), Los Angeles (Virtual), California, USA, June 2020.

C32. Kai Wan, Hua Sun, Mingyue Ji, Daniela Tuninetti, Giuseppe Caire, Novel Converse for Device-to-Device Demand-Private Caching with a Trusted Server, Proceedings of IEEE International Symposium on Information Theory (ISIT), Los Angeles (Virtual), California, USA, June 2020.

C31. Kai Wan, Hua Sun, Mingyue Ji, Daniela Tuninetti, Giuseppe Caire, Cache-Aided Scalar Linear Function Retrieval, Proceedings of IEEE International Symposium on Information Theory (ISIT), Los Angeles (Virtual), California, USA, June 2020.

C30. Xiang Zhang, Kai Wan, Hua Sun, Mingyue Ji, Giuseppe Caire, Private Cache-aided Interference Alignment for Multiuser Private Information Retrieval, Proceedings of 18th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOPT), Volos (Virtual), Greece, June 2020.

C29. Kai Wan, Hua Sun, Mingyue Ji, Daniela Tuninetti, Giuseppe Caire, Device-to-Device Private Caching with Trusted Server, Proceedings of IEEE International Conference on Communications (ICC), Dublin (Virtual), Ireland, June 2020.

C28. Hua Sun, Private Information Delivery, Proceedings of IEEE Information Theory Workshop (ITW), Visby, Sweden, August 2019 (Invited Paper).

C27. Qiwen Wang, Hua Sun, Mikael Skoglund, Symmetric Private Information Retrieval with Mismatched Coded Messages and Randomness, Proceedings of IEEE International Symposium on Information Theory (ISIT), Paris, France, July 2019.

C26. Ruida Zhou, Chao Tian, Tie Liu, Hua Sun, Capacity-Achieving Private Information Retrieval Codes from MDS-Coded Databases with Minimum Message Size, Proceedings of IEEE International Symposium on Information Theory (ISIT), Paris, France, July 2019.

C25. Xinping Yi, Hua Sun, Opportunistic Topological Interference Management, Proceedings of IEEE International Symposium on Information Theory (ISIT), Paris, France, July 2019.

C24. Hua Sun, Syed A. Jafar, The Capacity of Linear Computation Broadcast, Proceedings of IEEE International Conference on Communications (ICC), Shanghai, China, May 2019.

C23. Chao Tian, Hua Sun, Jun Chen, Capacity-Achieving Private Information Retrieval Codes with Optimal Message Size and Upload Cost, Proceedings of IEEE International Conference on Communications (ICC), Shanghai, China, May 2019.

C22. Yanliang Zhou, Hua Sun, Shengli Fu, On the Randomness Cost of Linear Secure Computation, Proceedings of 53rd Annual Conference on Information Sciences and Systems (CISS), Baltimore, USA, March 2019 (Invited Presentation).

C21. Qiwen Wang, Hua Sun, Mikael Skoglund, The ϵ-error Capacity of Symmetric PIR with Byzantine Adversaries, Proceedings of IEEE Information Theory Workshop (ITW), Guangzhou, China, November 2018.

C20. Qiwen Wang, Hua Sun, Mikael Skoglund, The Capacity of Private Information Retrieval with Eavesdroppers, Proceedings of 52nd Asilomar Conference on Signals, Systems, and Computers, Pacific Grove, USA, October 2018.

C19. Hua Sun, The Capacity of Anonymous Communications, Proceedings of IEEE International Symposium on Information Theory (ISIT), Vail, USA, June 2018.

C18. Chao Tian, Hua Sun, Jun Chen, A Shannon-Theoretic Approach to the Storage-Retrieval Tradeoff in PIR Systems, Proceedings of IEEE International Symposium on Information Theory (ISIT), Vail, USA, June 2018.

C17. Hua Sun, Syed A. Jafar, The Capacity of Private Computation, Proceedings of IEEE International Conference on Communications (ICC), Kansas City, USA, May 2018.

C16. Zhuqing Jia, Hua Sun, Syed A. Jafar, The Capacity of Private Information Retrieval with Disjoint Colluding Sets, Proceedings of IEEE Global Communications Conference (GLOBECOM), Singapore, December 2017.

C15. Hua Sun, Syed A. Jafar, Private Information Retrieval from MDS Coded Data with Colluding Servers: Settling a Conjecture by Freij-Hollanti et al., Proceedings of IEEE International Symposium on Information Theory (ISIT), Aachen, Germany, June 2017.

C14. Hua Sun, Syed A. Jafar, The Capacity of Private Information Retrieval with Colluding Databases, Proceedings of IEEE GLOBALSIP, Greater Washington, D.C., USA, December, 2016.

C13. Hua Sun, Syed A. Jafar, The Capacity of Private Information Retrieval, Proceedings of IEEE Global Communications Conference (GLOBECOM), Washington, DC, USA, December, 2016. (2016 GLOBECOM Best Paper Award).

C12. Hua Sun, Syed A. Jafar, The Capacity of Symmetric Private Information Retrieval, Proceedings of IEEE NETCOD, Washington, DC, USA, December, 2016.

C11. Hua Sun, Syed A. Jafar, Blind Interference Alignment for Private Information Retrieval, Proceedings of IEEE International Symposium on Information Theory (ISIT), Barcelona, Spain, July 2016. (2016 Jack Keil Wolf ISIT Student Paper Award).

C10. Bofeng Yuan, Hua Sun, Syed A. Jafar, On the Optimality of ‘‘Half the Cake‘‘ for K-user Rank-deficient (Mk X Mk) Interference Channel, Proceedings of IEEE Global Communications Conference (GLOBECOM), San Diego, USA, December 2015. (Finalist for 2015 GLOBECOM Best Paper Award).

C9. Hua Sun, Syed A. Jafar, On the Separability of GDoF Region for Parallel Gaussian TIN Optimal Interference Networks, Proceedings of IEEE International Symposium on Information Theory (ISIT), Hong Kong, China, June 2015.

C8. Hua Sun, Syed A. Jafar, Topological Interference Management with Multiple Antennas, Proceedings of IEEE International Symposium on Information Theory (ISIT), Honolulu, USA, July 2014.

C7. Hua Sun, Syed A. Jafar, On the Optimality of Treating Interference as Noise for Parallel Deterministic Interference Networks, Proceedings of IEEE International Symposium on Information Theory (ISIT), Honolulu, USA, July 2014.

C6. Chunhua Geng, Hua Sun, Syed A. Jafar, On the Optimality of Treating Interference as Noise: General Message Sets, Proceedings of IEEE International Symposium on Information Theory (ISIT), Honolulu, USA, July 2014.

C5. Chunhua Geng, Hua Sun, Syed A. Jafar, Multilevel Topological Interference Management, Proceedings of IEEE Information Theory Workshop (ITW), Seville, Spain, September 2013 (Invited Paper).

C4. Hua Sun, Chunhua Geng, Syed A. Jafar, Topological Interference Management with Alternating Connectivity, Proceedings of IEEE International Symposium on Information Theory (ISIT), Istanbul, Turkey, July 2013.

C3. Chenwei Wang, Hua Sun, Syed A. Jafar, Genie chains and the Degrees of Freedom of the K-user MIMO Interference Channel, Proceedings of IEEE International Symposium on Information Theory (ISIT), Boston, USA, July 2012.

C2. Hua Sun, Chunhua Geng, Tiangao Gou, Syed A. Jafar, Degrees of Freedom of MIMO X Networks: Spatial Scale Invariance, One-Sided Decomposability and Linear Feasibility, Proceedings of IEEE International Symposium on Information Theory (ISIT), Boston, USA, July 2012.

C1. Yunchuan Yang, Hui Zhao, Cong Sun, Hua Sun, Wenbo Wang, Distributed Beamforming with Relay-Aided Interference Alignment in Fully Connected Interference Network, Proceedings of IEEE GLOBECOM Workshops, Houston, USA, December 2011.