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: "towards focus on time"
  Abstract: spichkov/Institut fur Informatik, TU M¨ unchen,¨Boltzmannstr. 3, 85748 Garching, GermanyAbstract: On specifying and verifying timing system properties in a formal way.Keywords: Formal Methods, Speciﬁcation, Veriﬁcation, Real-Time SystemsSpecifying real-time systems, arguing about timing properties is hardly avoidable. The notionof time takes center stage for this kind of systems: abstracting from the time we may loose thecore properties of a system we represent, e.g. in many cases the causality property can be loosed.In particular, the timed domain is the most important one for representation of distributed systemswith real-time requirements.On the other hand, in many cases arguing about time makes the speciﬁcation more readablefor an average engineer: speciﬁcation of a real-time system in an untimed frame may be in somecases shorter or more elegant from mathematical point of view, but to understand such speciﬁca-tions and to argue about their properties is in many cases much more difﬁcult in comparison tothe corresponding speciﬁcations in a timed frame, where some properties like causality could berepresented explicitly. Moreover, abstraction from timing aspects can easily lead to speciﬁcationmistakes because of difﬁculties to ﬁnd a correct abstraction.One of the most well-established models for the speciﬁcation and veriﬁcation of real-timesystem design is representation of a system using timed automata, introduced by Alur andDill [AD94] – them extend the classical ﬁnite automata by a ﬁnite set of real valued clocksused to measure the time elapsed between events to constrain the runs of the automation. Themodel from Alur and Dill is well-developed, however, some its assumptions on the system couldbe too idealistic: timed automata assumes perfect continuity of clocks and, what could be evenmore critical if we deal with embedded systems, instantaneous reaction times. Another problemof this model is that it does not prevent Zeno runs [GB07]. To solve this, the idea of robust modelchecking was introduced by Puri [Pur00] and also revised in other approaches.We suggest another solution: to argue not about a single action or messages but about timeintervals containing a ﬁnite number of actions, i.e. to argue not about single messages in aninput stream, but about a sequence of messages that are present in this stream at some timeinterval. This sequence can be in general either empty or contain a single message or a numberof messages. In this approach a discrete model of time is used, because (i) this simpliﬁes thespeciﬁcation and, even more, the veriﬁcation of system properties, and (ii) any timed transitionsystem can be discretized without loss of generality. Thus, an input for our timed automata or,more generally, a timed component, is an inﬁnite sequence of ﬁnite time intervals.However a discrete model of time is used here, ones can choose any time granularity deﬁningthe concrete meaning of a time interval according to the system requirements, and, moreover,it is possible to switch from one time granularity to another: the operator s ’

Connected through hyperedge HE-1 (induced by source paper "stream processing components isabelle hol formalisation and case studies"):
  with members:
    - "from abstract modelling to remote cyber physical integration interoperability testing"
    - "towards system development methodologies from software to cyber physical domain"

Connected through hyperedge HE-2 (induced by source paper "from abstract modelling to remote cyber physical integration interoperability testing"):
  with members:
    - "towards system development methodologies from software to cyber physical domain"

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.FL(Formal Languages and Automata Theory)