Context-aware location discovery exchange in a ubiquitous environment

It becomes challenging in order to represent,discover and exchange location information in a ubiquitous environment due to dynamic movement and interaction between mobile nodes inside.In this paper,a new method is presented in order to make location information context-aware so that organizing the format of location information and maintaining the communication between direct connected nodes in a ubiquitous environment is enabled.The structure of a contextual location information repository and a context information communication protocol is manipulated to implement the proposed features.According to the simulation results in network simulator version2(NS2),the new method has depicted good discovery success and consumed efficient service discovery bandwidth.Other network traffic,i.e.transmission control protocol,(TCP) has been simulated in the scenarios but the new location-aware method has shown its robustness with continuous context discovery process.     

Context-aware BPEL workflow system using aspect-oriented programming

Business process execution language(BPEL)is a most recognized standard workflow language.However,it is difficult to be used in the ubiquitous system computing environment because it is difficult to describe the context information in the selection of the flow through the branch.To solve this problem,we propose a new BPEL workflow system with context-awareness by using aspect-oriented programming(AOP).This system is composed of a BPEL system module and a weaving module using AOP for context-aware.The BPEL system module generates a BPEL workflow program.And the weaving module converts a context-aware mark-up language(CAML)document to the aspect-oriented program that is applied to context-aware code without modification of the existing BPEL document.We also define a new document form that is called CAML,which provides a context-aware that is not available in BPEL.The system can generate a context-aware workflow program.It is developed in a way that inserts context information using AOP to provide context-aware services.     

基于谓词检测方法的上下文感知案例研究

当前,开发灵活的适应环境变化的上下文感知应用较为复杂。在上下文感知应用开发过程中,很多未知情况无法事先被充分考虑到,实际的开发又需要处理很多意外情形,因此有效地表示和处理上下文尤为重要。谓词检测作为实现上下文感知的重要方法之一,能够有效对上下文信息进行建模,但在实际应用中对于真实物理设备的支持如何在很大程度上仍然是未知的。为了应对以上问题,通过构建一个简单的物理场景,将谓词检测方法应用于真实的机器小车上,支持其在一个既定轨道上完成运行任务。在该场景下对原始的上下文环境进行建模,将环境特性逐步规约成特定的快照谓词和序列谓词,并在案例研究中,对规约化的谓词进行检测,将谓词检测应用于真实的机器小车实验上。实验分析的结果表明,谓词检测的方法能有效检测小车的上下文特性并成功支撑小车完成既定的行走目标。     

一种多层分布式情境装配模型

提出一种以Agent技术为基础的多层分布式的虚拟场景模型。先从装配体的视角构建装配信息模型,根据刻画特征对象的各项参数定义装配知识层;装配决策层将零件视为Agent,并定义Agent间传输状态参数的消息模板,同时根据虚拟装配任务的过程特点,建立决策规则;最后,定义用户控制层的运动控制算法,实现对用户的运动引导。实验表明该场景模型可在虚拟场景中有效呈现装配任务,并根据上下文情境准确理解用户意图。     

Adapting the User Context in Realtime: Tailoring Online Machine Learning Algorithms to Ambient Computing

Ambient systems weave computing and communication aspects into everyday life. To provide self-adaptive services, it is necessary to acquire context information using sensors and to leverage the collected information for reasoning and classification of situations. To enable self-learning systems, we propose to depart from static rule-based decisions and first-order logic to define situations from basic context, but to build on machine-learning techniques. However, existing learning algorithms show substantial weaknesses if applied in highly dynamic environments, where we expect accurate decisions in realtime while the user is in-the-loop to give feedback to the system’s recommendations. To address ambient and pervasive computing environments, we propose the FLORA—multiple classification (FLORA-MC) online learning algorithm. In particular, we enhance the FLORA algorithm to allow for (1) multiple classification and (2) numerical input values, while improving its concept drift handling capabilities; thus, making it an excellent choice for use in the area of ambient computing. The multiple classification allows context-aware systems to differentiate between multiple categories instead of taking binary decisions. Support for numerical input values enables the processing of arbitrary sensor inputs beyond nominal data. To provide the capability of concept drift handling, we propose the use of an advanced window adjustment heuristic, which allows FLORA-MC to continuously adapt to the user’s behavior, even if her/his preferences change abruptly over time. In combination with the inherent characteristics of online learning algorithms, our scheme is very well suited for realtime application in the area of ambient and pervasive computing. We describe the design and implementation of FLORA-MC and evaluate its performance vs. state-of-the-art learning algorithms. We are able to show the superior performance of our algorithm with respect to reaction time and concept drift handling, while maintaining an excellent accuracy. Our implementation is available to the research community as a WEKA module.     

上下文感知的树递归神经网络下隐式情感分析

针对现有的序列化模型对中文隐式情感分析中特征信息提取不准确以及对篇章级的文本信息提取存在的梯度爆炸或者梯度消失的问题,提出了双向长短时神经网络和上下文感知的树形递归神经网络(context-aware tree recurrent neutral network,CA-TRNN)的并行混合模型.该模型分别利用双向循环长...     

The Anatomy of a Context-Aware Application

We describe a sensor-driven, or sentient, platform for context-aware computing that enables applications to follow mobile users as they move around a building. The platform is particularly suitable for richly equipped, networked environments. The only item a user is required to carry is a small sensor tag, which identifies them to the system and locates them accurately in three dimensions. The platform builds a dynamic model of the environment using these location sensors and resource information gathered by telemetry software, and presents it in a form suitable for application programmers. Use of the platform is illustrated through a practical example, which allows a user's current working desktop to follow them as they move around the environment.     

面向情境感知的不确定性数据融合策略

情境感知计算是对传感器感知的数据进行融合从而得到用户情境信息的过程。文中针对传感器数据存在的不确定性问题,在Context Toolkit模型的基础上提出了一种面向情境感知的数据融合策略,把数据融合分为底层融合和高层融合,在这两层上分别采用模糊逻辑和动态贝叶斯网络的数据融合方法。仿真实验结果表明,这种将模糊逻辑和动态贝叶斯网络相结合的策略能有效地处理情境感知过程中的不确定数据和信息,从而提高情境感知计算的容错性和准确度。     

支持上下文感知的构件适配模型研究

为了对普适环境下的构件化应用提供支持,扩展传统的构件适配技术,在上下文感知中间件的基础上,提出支持上下文感知的构件适配模型CACAM和构件适配算法CACA,实现对环境、用户上下文的动态感知和重配置。实验结果表明,该模型能够有效地实现普适计算环境下基于上下文感知的构件适配。     

上下文感知推荐系统

近年来,上下文感知推荐系统已成为推荐系统研究领域最为活跃的研究领域之一.如何利用上下文信息进一步提高推荐系统的推荐精确度和用户满意度,成为上下文感知推荐系统的主要任务.从面向过程的角度对最近几年上下文感知推荐系统的研究进展进行综述,对其系统框架、关键技术、主要模型、效用评价以及应用实践等进行了前沿概括、比较和分析.最后,对上下文感知推荐系统有待深入的研究难点和发展趋势进行了展望.