Deployment strategies for distributed complex event processing

Several complex event processing (CEP) middleware solutions have been proposed in the past. They act by processing primitive events generated by sources, extracting new knowledge in the form of composite events, and delivering them to interested sinks. Event-based applications often involve a large number of sources and sinks, possibly dispersed over a wide geographical area. To better support these scenarios, the CEP middleware can be internally built around several, distributed processors, which cooperate to provide the processing and routing service. This paper introduces and compares different deployment strategies for a CEP middleware, which define (i) how the processing load is distributed over different processors and (ii) how these processors interact to produce the required results and to deliver them to sinks. Our evaluation compares the presented solutions and shows their benefits with respect to a centralized deployment, both in terms of network traffic and in terms of forwarding delay.     

Low latency complex event processing on parallel hardware

Most complex information systems are event driven: each part of the system reacts to the events happening in the other parts, potentially generating new events. Complex event processing (CEP) engines in charge of interpreting, filtering, and combining primitive events to identify higher level composite events according to a set of rules are the new breed of message-oriented middleware, which is being proposed today to better support event-driven interactions.     

RFID数据流分布式层次复杂事件处理

当前RFID应用中的复杂事件处理通常采用集中式的体系结构,这样不能适用于分布式的应用,并且由于存在单点失效和网络拥塞而缺乏健壮性和可伸缩性。同时,很多高效的RFID复杂事件处理方法不能很好地支持层次复杂事件。提出了一种基于CORBA的分布式层次复杂事件处理模型以及高效的基于查询规划的分布式层次复杂事件处理方法。实验结果表明该方法在处理大规模的分布式RFID应用时是有效的。     

支持复合事件的模型及其在中间件中的应用

介绍了COM的可连接对象技术和对复合事件的识别过程,给出了在可连接对象技术基础上进行改进和扩展的EFL事件模型,并且在其中加入了对复合事件的支持,此外还阐述了利用XML对事件进行表述的方法。介绍了基于EFL构件模型的反射式中间件PURPLE,并着重说明了EFL事件机制在PURPLE环境监测和自适应过程中的应用。     

A complex event routing infrastructure for distributed systems

With the growing number of mega services and cloud computing platforms, industrial organizations are utilizing distributed data centers at increasing rates. Rather than the request/reply model, these centers use an event-based communication model. Traditionally, the event-based middleware and the Complex Event Processing (CEP) engine are viewed as two distinct components within a distributed system’s architecture. This division adds additional system complexity and reduces the ability for consuming applications to fully utilize the CEP toolset. This article will address these issues by proposing a novel event-based middleware solution. We introduce Complex Event Routing Infrastructure (CERI), a single event-based infrastructure that serves as an event bus and provides first class integration of CEP. An unstructured peer-to-peer network is exploited to allow for efficient event transmission. To reduce network flooding, superpeers and overlay network partitioning are introduced. Additionally, CERI provides each client node the capability of local complex query evaluation. As a result, applications can offload internal logic to the query evaluation engine in an efficient manner. Finally, as more client nodes and event types are added to the system, the CERI can scale up. Because of these favorable scaling properties, CERI serves as a foundational step in bringing event-based middleware and CEP closer together into a single unified infrastructure component.     

CEPSim: Modelling and simulation of Complex Event Processing systems in cloud environments

The emergence of Big Data has had profound impacts on how data are stored and processed. As technologies created to process continuous streams of data with low latency, Complex Event Processing (CEP) and Stream Processing (SP) have often been related to the Big Data velocity dimension and used in this context. Many modern CEP and SP systems leverage cloud environments to provide the low latency and scalability required by Big Data applications, yet validating these systems at the required scale is a research problem per se. Cloud computing simulators have been used as a tool to facilitate reproducible and repeatable experiments in clouds. Nevertheless, existing simulators are mostly based on simple application and simulation models that are not appropriate for CEP or for SP. This article presents CEPSim, a simulator for CEP and SP systems in cloud environments. CEPSim proposes a query model based on Directed Acyclic Graphs (DAGs) and introduces a simulation algorithm based on a novel abstraction called event sets. CEPSim is highly customizable and can be used to analyse the performance and scalability of user-defined queries and to evaluate the effects of various query processing strategies. Experimental results show that CEPSim can simulate existing systems in large Big Data scenarios with accuracy and precision.     

A model-driven approach for facilitating user-friendly design of complex event patterns

Complex Event Processing (CEP) is an emerging technology which allows us to efficiently process and correlate huge amounts of data in order to discover relevant or critical situations of interest (complex events) for a specific domain. This technology requires domain experts to define complex event patterns, where the conditions to be detected are specified by means of event processing languages. However, these experts face the handicap of defining such patterns with editors which are not user-friendly enough. To solve this problem, a model-driven approach for facilitating user-friendly design of complex event patterns is proposed and developed in this paper. Besides, the proposal has been applied to different domains and several event processing languages have been compared. As a result, we can affirm that the presented approach is independent both of the domain where CEP technology has to be applied to and of the concrete event processing language required for defining event patterns.     

Bat4CEP: a bat algorithm for mining of complex event processing rules

Complex Event Processing (CEP) is a modern software technology for the dynamic analysis of continuous data streams. CEP is able of searching extremely large data streams in real time for the presence of event patterns. So far, specifying event patterns of CEP rules is still a manual task based on the expertise of domain experts. This paper presents a novel bat-inspired swarm algorithm for automatically mining CEP rule patterns that express the relevant causal and temporal relations hidden in data streams. The basic suitability and performance of the approach is proven by extensive evaluation with both synthetically generated data and real data from the traffic domain.

     

基于复杂事件处理的业务规则管理系统的研究

复杂事件处理技术目前已经广泛用于各个行业,特别是大数据量,行为规则很多且在系统运行阶段规则变化比较繁琐的产业。比如航空监管,通信,能源,网络,公共,证券市场等。该文介绍了复杂事件处理技术的基本概念和实现原理,并在复杂事件处理技术的启发下开发了业务规则管理系统。传统的企业应用程序开发中把业务策略硬编码到系统中,更新系统的过程需要专门的编程人员,并且会使系统稳定性面临风险,同时需要花费较长的时间。随着系统业务的日趋复杂,将复杂的业务逻辑处理模块与非业务模块分离的必要性也越来越高。采用高效的业务规则管理系统来处理复杂业务逻辑,开发人员和架构设计者可以从应用程序传统代码中提取业务逻辑。将为系统的构建和维护节省大量的人力和物力成本,并大大提高系统对业务规则修改的响应效率。     

大数据复杂事件分析方法研究与应用

复杂事件处理（Complex Event Processing, CEP）是一项伴随流式数据而出现的技术,用于不同数据源顺序混杂的事件流中发现感兴趣的事件模式。然而,随着数据量的不断递增,传统的CEP技术往往不能满足在大数据集上有效获取事件模式的处理需求。针对这一问题,本文结合数据挖掘中聚类分析与关联规则的思想,提出一种“复杂事件处理”算法,〖JP2〗并把其部署到分布式平台Hadoop上,从而发现大数据集中的复杂事件关系,有效地改变了传统技术面临海量数据的局限性。最后,应用本文算法到GPS大数据集中,发现其中的复杂事件模式,并通过实验验证本文方法具有可行性与有效性。     

一种独立于应用程序的多点触摸交互中间件*

在对鼠标事件特性分析和触摸手势描述的基础上,设计实现了一种基于鼠标事件映射的多点触摸交互中间件,包括声明法、映射法两种实现途径。该中间件能够不进行程序改造而在传统基于鼠标交互的应用程序上实现多点触摸,具有平台无关的通用性。最后通过在多款地理信息系统软件中的应用对该中间件进行了验证和评估。     

Distributed Reactive XML

XML-centric models of computation have been proposed as an answer to the demand for interoperability, heterogeneity and openness in coordination models. We present a prototype implementation of an open XML-centric coordination middleware called Distributed Reactive XML. The middleware has as theoretical foundation a general distributed extensible process calculus inspired by the theory of Bigraphical Reactive Systems. The calculus is extensible just as XML is extensible, in that its signature and reaction rules are not fixed. It is distributed by allowing both the state of processes as well as the set of reaction rules to be distributed (or partly shared) between different clients. The calculus is implemented by representing process terms as XML documents stored in a value-oriented, peer-to-peer XML Store and reaction rules as XML transformations performed by the clients. The formalism does not require that only process terms are stored—inside process terms one may store application specific data as well. XML Store provides transparent sharing of process terms between all participating peers. Conflicts between concurrent reaction rules are handled by an optimistic concurrency control. The implementation thus provides an open XML-based coordination middleware with a formal foundation that encompasses both the shared data, processes and reaction rules.     

基于CEP的RFID数据处理模型研究

RFID数据处理技术是近年来射频识别技术应用研究的热点。本文针对RFID数据的特点以及目前RFID数据处理技术的不足,探讨了将复杂事件处理（CEP）技术应用于RFID数据处理的具体技术问题,提出一种基于CEP的RFID数据处理模型,重点对高速缓存cache、事件滤波器以及复杂事件构建器等关键技术进行了研究,对该处理模型的应用进行了讨论。     

Seamless User-Level Handoff in Ubiquitous Multimedia Service Delivery

Advancing mobile computing technologies are enabling ubiquitous personal computing environment. In this paper, we focus on an important problem in such environment: user mobility. In the case of user mobility, a user is free to access his/her personalized service at anytime, anywhere, through any possible mobile/fixed devices. Providing mobility support in this scenario poses a series of challenges. The most essential problem is to preserve the user's access to the same service despite changes of the accessing host or service provider. Existing system-level mobility solutions are insufficient to address this issue since it is not aware of the application semantics. On the other hand, making each application to be mobility-aware will greatly increase the development overhead. We argue that the middleware layer is the best place to address this problem. On one hand, it is aware of application semantics. On the other hand, by building application-neutral mobility functions in the middleware layer, we eliminate the need to make each application mobility-aware. In this paper, we design a middleware framework to support user mobility in the ubiquitous computing environment. Its major mobility functions include user-level handoff management and service instantiation across heterogeneous computing platforms. We validate the major mobility functions using our prototype middleware system, and test them on two multimedia applications (Mobile Video Player and Mobile Audio Player). To maximally approximate the real-world user-mobility scenario, we have conducted experiments on a variety of computing platforms and communication paradigms, ranging from T1-connected high-end PC to handheld devices with wireless networks. The results show that our middleware framework is able to provide efficient user mobility support in the heterogeneous computing environment.     

Conformance checking of processes based on monitoring real behavior

Many companies have adopted Process-aware Information Systems (PAIS) to support their business processes in some form. On the one hand these systems typically log events (e.g., in transaction logs or audit trails) related to the actual business process executions. On the other hand explicit process models describing how the business process should (or is expected to) be executed are frequently available. Together with the data recorded in the log, this situation raises the interesting question “Do the model and the log conform to each other?”. Conformance checking, also referred to as conformance analysis, aims at the detection of inconsistencies between a process model and its corresponding execution log, and their quantification by the formation of metrics. This paper proposes an incremental approach to check the conformance of a process model and an event log. First of all, the fitness between the log and the model is measured (i.e., “Does the observed process comply with the control flow specified by the process model?”). Second, the appropriateness of the model can be analyzed with respect to the log (i.e., “Does the model describe the observed process in a suitable way?”). Appropriateness can be evaluated from both a structural and a behavioral perspective. To operationalize the ideas presented in this paper a Conformance Checker has been implemented within the ProM framework, and it has been evaluated using artificial and real-life event logs.     

MEdit4CEP-CPN: An approach for complex event processing modeling by prioritized colored petri nets

Complex Event Processing (CEP) is an event-based technology that allows us to process and correlate large data streams in order to promptly detect meaningful events or situations and respond to them appropriately. CEP implementations rely on the so-called Event Processing Languages (EPLs), which are used to implement the specific event types and event patterns to be detected for a particular application domain. To spare domain experts this implementation, the MEdit4CEP approach provides them with a graphical modeling editor for CEP domain, event pattern and action definition. From these graphical models, the editor automatically generates a corresponding Esper EPL code. Nevertheless, the generated code is syntactically but not semantically validated. To address this problem, MEdit4CEP is extended in this paper by Prioritized Colored Petri Net (PCPN) formalism, resulting in the MEdit4CEP-CPN approach. This approach provides both a novel PCPN domain-specific modeling language and a graphical editor. By using model transformations, event pattern models can be automatically transformed into PCPN models, and then into the corresponding PCPN code executable by CPN Tools. In addition, by using PCPNs we can compare the expected output with the actual output and can even conduct a quantitative analysis of the scenarios of interest. To illustrate our approach, we have conducted an air quality level detection case study and we show how this novel approach facilitates the modeling, simulation, analysis and semantic validation of complex event-based systems.     

Formally based tool support for model checking Erlang applications

Model checking as a verification technique has proved effective at the system design and hardware level, and is now beginning to be applied to program code. In this paper, we study the application of model checking techniques in the development of Erlang systems. Erlang is a concurrent functional language with specific support for the development of distributed, fault-tolerant systems with soft real-time requirements. It was designed from the start to support a concurrency-oriented programming paradigm and large distributed implementations that this supports. The methodology we describe in this paper consists of abstracting the behaviour of Erlang and OTP components into a process algebraic specification, specifically an mCRL2 specification, upon which the standard model checker CADP can be used to verify the system’s properties. In addition to rules that model the Erlang syntax, a translation mechanism for the OTP modules gen_server, supervisor and gen_fsm, and the timeout event are defined. A tool-set etomcrl2 has been developed to automate the process of translation. A small illustrative example is used to evaluate the effectiveness of the proposed techniques, and its results show that the proposed techniques are effective in both verifying properties as well as distinguishing between correct and faulty implementations of the design.     

Enabling portability in advanced information-centric services over structured peer-to-peer systems

A common factor among all the existing distributed, peer-to-peer systems is their lack of genericity. Typically, information-centric services (such as range queries) are deployed ad-hoc onto a specific peer-to-peer overlay. These kinds of solutions make them probably efficient but non-portable to other peer-to-peer infrastructures, and so the services and applications constructed over them. We do believe, instead, that a peer-to-peer-generic solution is feasible. In this paper, we tackle the genericity and portability issue specifically on structured peer-to-peer networks (SPNs).To do so, we introduce a distributed 3-layer architecture, which abstracts applications (on top of the architecture) and the peer-to-peer network currently in use (in the bottom layer). Our middleware appears in the middle layer, which is responsible to address two major challenges: (i) supporting complex, multi-dimensional application data domains and (ii) performing efficiently for a wide variety of information-centric services in the large scale.Broadly speaking, information-centric services are classified as data management (such as range or spatial queries) and content distribution services (like publish/subscribe), and our middleware is an umbrella for all them. Notice that data management services are based on the pull mode (i.e., a user lookups information previously stored in the system), whilst content distribution services obey to a push mode (i.e., the system delivers the information timely to users).The benefits of our approach are clear: (i) Our middleware can be easily deployed over existing SPNs, guaranteeing the portability of a critical mass of services and end-user applications; (ii) Several services can be added to the middleware, which will facilitate the appearance of new synergies; and (iii) our middleware deals with the application data domain transparently to services and applications, including the necessary algorithms for services to be efficiently deployed into our middleware.