Runtime software architecture based on reflective middleware

Copyright by Science in China Press 2004 Since its first literate identification and discussion[1], software architecture (SA) has become an important subfield of software engineering, receiving increasing attention from both academic and industrial communities. SA describes the gross structure of a software system with a collection of components, connectors and constraints[2]. In gen-eral, SA acts as a bridge between requirements and implementation and provides a blue-print for system cons…     

基于数据中台架构的数据管理研究

为了解决数据问题,数据管理技术的价值得到了多家公司的认可,并出现了许多关于数据管理的想法和研究。然而,在实际的业务数据管理中,仍然存在一些问题。因此,文章基于对数据中台架构的数据管理进行了深入分析。     

基于分布式中间件ICE的应用架构研究

在分布式系统中,分布式平台之间的差异增加了开发的复杂性.基于一种轻量级的分布式中间件ICE,提出了在分布式异构环境中的一般架构模型.该模型可以降低模块之间的耦合度,解决服务器负载过大的问题.将该模型应用到网络安全管理系统中,解决了网络安全管理系统中平台差异问题和服务器负载均衡问题.     

基于上下文感知移动中间件的研究与设计

移动环境和设备的限制,给移动开发带来了挑战。移动中间件能够为移动应用开发提供了一个很好的基础平台。叙述了自适应机制在中间件层实现的必要性,分析了传统面向对象中间件应用在移动计算环境中的不足。根据移动应用的需求,提出了一个基于上下文感知的移动中间件体系结构。     

A resource and context model for mobile middleware

Mobile computing systems should be self-managed to simplify operation and maintenance plus meet user’s expectation with respect to Quality of Service (QoS). When architecting self-managed mobile computing systems, one must take a holistic view on both QoS management and the entities in the mobile environment. This paper presents a novel model that includes both resources and context elements. To illustrate the usefulness of the model, it is applied to a video streaming application by: (1) modelling context elements and resources in the environment, (2) specifying context dependencies and QoS characteristics of the application, and (3) designing weakly integrated resource and context managers. We describe a middleware that uses the developed managers when evaluating context dependencies and predict offered QoS of alternative implementations of the application. In order to select the one that can operate in the current environment and that best satisfies given user preferences.     

基于上下文相关的软件体系结构求精方法

为了提高软件体系结构求精的精确性与可追溯性,使处于不同抽象层次之间的体系结构之间形成规范的映射体系,引入了形式化方法,定义了一种基于上下文相关文法的形式化的求精文法,并将该文法应用到体系结构求精中,给出了基于构件的体系结构形式化求精过程.最后,基于体系结构求精方法建立了相应的用于指导软件开发的模型.     

A pluggable middleware architecture for developing context-aware mobile applications

The proliferation of powerful smartphone devices provides a great opportunity for context-aware mobile applications becoming mainstream. However, we argue that conventional software development techniques suffer because of the added complexity required for collecting and managing context information. This paper presents a component-based middleware architecture which facilitates the development and deployment of context-aware applications via reusable components. The main contribution of this approach is the combination of a development methodology with the middleware architecture, which together bring significant value to developers of context-aware applications. Further contributions include the following: The methodology utilizes separation of concerns, thus decreasing the developmental cost and improving the productivity. The design and implementation of context-aware applications are also eased via the use of reusable components, called context plug-ins. Finally, the middleware architecture facilitates the deployment and management of the context plug-ins in a resource-aware manner. The proposed methodology and middleware architecture are evaluated both quantitatively and qualitatively.     

ID-Services: an RFID middleware architecture for mobile applications

The use of RFID middleware to support application development for and integration of RFID hardware into information systems has become quite common in RFID applications where reader devices remain stationary, which currently represents the largest part of all RFID applications in use. Another field for applying RFID technology which is offering a huge set of novel possibilities and applications are mobile applications, where readers are no longer fixed. In order to address the specific issues of mobile RFID-enabled applications and to support developers in rapid application development, we present ID-Services, an architecture for an RFID middleware that is designed to support mobile applications. The ID-Services approach has been used to implement MoVIS (Mobile Visitor Information System), a mobile application which allows museum visitors to request individually adapted multimedia information about exhibits in an intuitive way.     

Prototypical implementation of location-aware services based on a middleware architecture for super-distributed RFID tag infrastructures

We provide evidence of the feasibility and effectiveness of a middleware architecture for mobile devices (MoDs), which employs dense distributions of small computerized entities for providing fault-tolerant location-aware services. We do so by describing exemplary implementations based on radio frequency identification as an enabling technology. Firstly, we present prototypical implementations of the hardware abstraction layer and of selected core middleware services. The latter enable a MoD to store and retrieve data and position information in physical places in a fault-tolerant manner, and to identify places based on a location abstraction which is robust against failure of individual tags. Secondly, we investigate the feasibility of some higher-level services and applications by developing and evaluating prototypical systems for tracing and tracking, self-positioning, and collaborative map-making.

Interactive self-reflection and its architecture based on cellular automata

This paper proposes a novel concept ofinteractive self-reflection (ISR), and claims its importance and necessity for implementingautonomy. Concretely, ISR includes three elements that (a) precisely recognize the current situation by determining the boundary between self and others, (b) appropriately detect or produce the required information according to a sense of values, and (c) autonomously generate both the goal and the evaluation criteria. To address these issues on ISR, we implement an ISR architecture based on cellular automata, and investigate its adaptation ability as one aspect of autonomy. Through intensive simulations, we reveal the following implications: (1) the ISR architecture provides a high level of adaptability that cannot be obtained by either adaptation to the environment or adaptation from the environment; (2) the adaptability of the architecture is supported by appropriate interaction control between adaptation to the environment and adaptation from the environment. This work was presented in part at the Fifth International Symposium on Artificial Life and Robotics, Oita, Japan, January 26–28, 2000     

Programmable context awareness framework

Context-awareness enables applications to provide end-users with a richer experience by enhancing their interactions with contextual information. Several frameworks have already been proposed to simplify the development of context-aware applications. These frameworks are focused on provisioning context data and on providing common semantics, definitions and representations of these context data. They assume that applications share the same semantic, which limits the range of use cases where a framework can be used, as that assumption induces a strong coupling between context management and application logic. This article proposes a framework that decouples context management from application business logic. The aim is to reduce the overhead on applications that run on resource-limited devices while still providing mechanisms to support context-awareness and behavior adaptation. The article presents an innovative approach that involves third-parties in context processing definition by structuring it using atomic functions. These functions can be designed by third-party developers using an XML-based programming language. Its implementation and evaluation demonstrates the benefits, in terms of flexibility, of using proven design patterns from software engineering for developing context-aware application.     

BiSNET: A biologically-inspired middleware architecture for self-managing wireless sensor networks

This paper describes BiSNET (Biologically-inspired architecture for Sensor NETworks), a middleware architecture that addresses several key issues in multi-modal wireless sensor networks (MWSNs) such as autonomy, scalability, adaptability, self-healing and simplicity. Based on the observation that various biological systems have developed mechanisms to overcome these issues, BiSNET follows certain biological principles such as decentralization, food gathering/storage and natural selection to design MWSN applications. In BiSNET, each application consists of multiple software agents, which operate on the BiSNET middleware platform in individual sensor nodes, and each agent exploits certain biologically-inspired mechanisms such as energy exchange, pheromone emission, replication, migration and death. This is analogous to a bee colony (application) consisting of multiple bees (agents). This paper describes the biologically-inspired mechanisms in BiSNET, and evaluates their impacts on the autonomy, scalability, adaptability, self-healing and simplicity of MWSNs. Simulation results show that BiSNET allows sensor nodes (agents and platforms) to be scalable with respect to network size, autonomously adapt their sleep periods for power efficiency and responsiveness of data collection, adaptively aggregate data from different types of sensor nodes, and collectively self-heal (i.e., detect and eliminate) false positive sensor data. The BiSNET platform is implemented simple in its design and lightweight in its memory footprint.     

A middleware architecture for disseminating delay-constrained information in wireless sensor networks

Data dissemination is a process where information is transmitted towards different destinations. In order to prevent accidents, coordinate rescue operations and warn people about critical events, this process imposes end-to-end delay constraints. Accordingly, the delay from each source to each destination should be monitored. For this purpose, a middleware is required between the network and the applications, offering the tracking capabilities of disseminated information. In this paper, we propose a middleware architecture for disseminating delay-constrained information in Wireless Sensor Networks (WSNs). In order to evaluate the feasibility of such architecture, a proof of concept of a real scenario is implemented. For performance evaluation, the end-to-end delay and the percentage of success related to the disseminated information are analyzed. Such analysis reveals that the middleware offers a percentage of success close to 98%, which is highly superior to the success of individual resources, such as Short Message Services (SMS), emailing and twitter.     

基于情境上下文的智能虚拟装配动作预测模型

针对现有虚拟装配系统普遍缺乏对复杂情境的分析能力,难以根据上下文有效预测用户动作意图的问题,给出了虚拟装配中情境上下文的形式化定义,建立了智能虚拟装配动作预测模型.该模型通过对装配动作模式的挖掘,进行基于实例的动作意图预测,实现系统的智能虚拟装配.结合水轮发电机组的转轮体装配实例,给出了模型的实现框架.通过实验验证,该模型能够根据情境上下文准确预测用户的动作意图,实时调整零部件的动作以自动完成装配.     

SPAD: A distributed middleware architecture for QoS enhanced alternate path discovery

In the next generation Internet, the network will evolve from a plain communication medium into one that provides endless services to the users. These services will be composed of multiple cooperative distributed application elements. We name these services overlay applications. The cooperative application elements within an overlay application will build a dynamic communication mesh, namely an overlay association. The Quality of Service (QoS) perceived by the users of an overlay application greatly depends on the QoS experienced on the communication paths of the corresponding overlay association. In this paper, we present super-peer alternate path discovery (SPAD), a distributed middleware architecture that aims at providing enhanced QoS between end-points within an overlay association. To achieve this goal, SPAD provides a complete scheme to discover and utilize composite alternate end-to-end paths with better QoS than the path given by the default IP routing mechanisms.     

Bayesian approach to sensor-based context awareness

The usability of a mobile device and services can be enhanced by context awareness. The aim of this experiment was to expand the set of generally recognizable constituents of context concerning personal mobile device usage. Naive Bayesian networks were applied to classify the contexts of a mobile device user in her normal daily activities. The distinguishing feature of this experiment in comparison to earlier context recognition research is the use of a naive Bayes framework, and an extensive set of audio features derived partly from the algorithms of the upcoming MPEG-7 standard. The classification was based mainly on audio features measured in a home scenario. The classification results indicate that with a resolution of one second in segments of 5–30 seconds, situations can be extracted fairly well, but most of the contexts are likely to be valid only in a restricted scenario. Naive Bayes framework is feasible for context recognition. In real world conditions, the recognition accuracy using leave-one-out cross validation was 87% of true positives and 95% of true negatives, averaged over nine eight-minute scenarios containing 17 segments of different lengths and nine different contexts. Respectively, the reference accuracies measured by testing with training data were 88% and 95%, suggesting that the model was capable of covering the variability introduced in the data on purpose. Reference recognition accuracy in controlled conditions was 96% and 100%, respectively. However, from the applicability viewpoint, generalization remains a problem, as from a wider perspective almost any feature may refer to many possible real world situations.     

An architecture for exporting environment awareness to mobilecomputing applications

In mobile computing, factors such as add-on hardware components and heterogeneous networks result in an environment of changing resource constraints. An application in such a constrained environment must adapt to these changes so that available resources are properly utilized. We propose an architecture for exporting awareness of the mobile computing environment to an application. In this architecture, a change in the environment is modeled as an asynchronous event that includes information related to the change. Events are typed and are organized as an extensible class hierarchy so that they can be handled at different levels of abstraction according to the requirement of each application. We also compare two approaches to structure an adaptive application. One addresses the problem of incorporating adaptiveness into legacy applications, while the other considers the design of an application with adaptiveness in mind