human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "a cache energy optimization technique for stt ram last level cache"
  Abstract: Last level caches (LLCs) occupy a large chip-area and there size is expected to grow further to offset the limitations of memory bandwidth and speed. Due to high leakage consumption of SRAM device, caches designed with SRAM consume large amount of energy. To address this, use of emerging technologies such as spin torque transfer RAM (STT-RAM) has been investigated which have lower leakage power dissipation. However, the high write latency and power of it may lead to large energy consumption which present challenges in its use. In this report, we propose a cache reconfiguration based technique for improving the energy efficiency of STT-RAM based LLCs. Our technique dynamically adjusts the active cache size to reduce the cache leakage energy consumption with minimum performance loss. We choose a suitable value of STT-RAM retention time for avoiding refresh overhead and gaining performance. Single-core simulations have been performed using SPEC2006 benchmarks and Sniper x86-64 simulator. The results show that while, compared to an STT-RAM LLC of similar area, an SRAM LLC incurs nearly 100% loss in energy and 7.3% loss in performance; our technique using STT-RAM cache saves 21.8% energy and incurs only 1.7% loss in performance.

Question: Please tell me which class the center node belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.AR(Hardware Architecture)