Support for situation awareness in trustworthy ubiquitous computing application software

Due to the dynamic and ephemeral nature of ubiquitous computing (ubicomp) environments, it is especially important that the application software in ubicomp environments is trustworthy. In order to have trustworthy application software in ubicomp environments, situation‐awareness (SAW) in the application software is needed to enforce flexible security policies and detect violations of security policies. In this paper, an approach is presented to provide development and runtime support to incorporate SAW in trustworthy ubicomp application software. The development support is to provide SAW requirement specification and automated code generation to achieve SAW in trustworthy ubicomp application software, and the runtime support is for context acquisition, situation analysis and situation‐aware communication. To realize our approach, the improved Reconfigurable Context‐Sensitive Middleware (RCSM) is developed to provide the above development and runtime support. Copyright © 2006 John Wiley & Sons, Ltd.     

Service integration with UPnP agent for an ubiquitous home environment

Consumer electronics and intelligent appliances can be successful and widely used in a smart or ubiquitous home environment. Service integration had become an important issue for system development. In this paper, we present an approach for UPnP devices connecting to outer networks via UPnP aware gateway. We develop service on a smart campus network based on enhanced UPnP technologies as an example. Under such framework, intelligent system provides users individual information at the right place and the right time.     

Designing for ubiquity: the perception of privacy

Ubicomp researchers have long argued that privacy is a design issue, and it goes without saying that successful design requires that we understand the desires, concerns, and awareness of the technology's users. Yet, because ubicomp systems are relatively unusual, too little empirical research exists to inform designers about potential users. Complicating design further is the fact that ubicomp systems are typically embedded or invisible, making it difficult for users to know when invisible devices are present and functioning. As early as 1993, ubicomp researchers recognized that embedded technology's unobtrusiveness both belies and contributes to its potential for supporting potentially invasive applications. Not surprisingly, users' inability to see a technology makes it difficult for them to understand how it might affect their privacy. Unobtrusiveness, nevertheless, is a reasonable goal because such systems must minimize the demands on users. To investigate these issues further, I conducted an ethnographic study of what I believe is the first US eldercare facility to use a sensor-rich environment. Our subjects were normal civilians (rather than ubicomp researchers) who lived or worked in a ubiquitous computing environment. We interviewed residents, their family members, and the facility's caregivers and managers. Our questions focused on how people understood both the ubiquitous technology and its effect on their privacy. Although the embedded technology played a central role in how people viewed the environment, they had a limited understanding of the technology, thus raising several privacy, design, and safety issues.     

基于VxWorks的嵌入式网管代理在IP电话网关适配器中的实现

IP电话网关适配器是IPGW和PBX结合的产品,跨接在IP网和电路交换网之间。它作为协议格式转换器和数据格式转换器,是IP电话网中比较复杂的部件。SNMPAgent在IP电话网关适配器中的实现程度决定着整个IP电话网络的可管性。该文结合IP电话网关适配器设计的实际要求,给出了一个基于VxWorks操作系统的SNMPAgent的实现实例,并从实用角度出发,对Agent的模块性、安全性、独立性给予了必要的改进和完善。     

Ubiquitous Computing aus betriebswirtschaftlicher Sicht

This paper identifies and analyses potential business benefits of ubiquitous computing (ubicomp). Its aim is to challenge whether the growing visibility of topics such as ubiquitous or pervasive computing, automatic identification (Auto-ID) and radio frequency identification (RFID) can be justified from a business perspective. To do so it analyses the business contribution of existing ubicomp applications, reconstructs their development phases, introduces the business relevant base-functionalities and discusses implications on the design of products, processes and services using ubicomp applications. The creation of an alternative and rather cost efficient machine-machine-relation between already established information systems and the real world things they try to manage has been identified as the main source of business benefit. However, before businesses can systematically leverage all potential benefits, some technical and political questions, such as creating robust solutions and solving privacy issues, have to be answered.     

Petri net tools for the specification and analysis of discretecontrollers

An approach is presented for the specification, modeling, and analysis of discrete-state systems and controllers. The approach features a rule-based state-variable-specification formalism that is translated into Petri net models composed of interconnected state machines. The concept of reduced reachability graphs is introduced as a means of reducing the computational effort required to isolate and analyze subcomponent behavior within the system. The target application is discrete manufacturing systems where the costs involved in writing, debugging, and maintaining of code for online process control can be significantly reduced through the use of automated modeling and analysis techniques. The approach is illustrated by an example of a simple discrete-state system     

Formal testing of timed graph transformation systems using metric temporal graph logic

Embedded real-time systems generate state sequences where time elapses between state changes. Ensuring that such systems adhere to a provided specification of admissible or desired behavior is essential. Formal model-based testing is often a suitable cost-effective approach. We introduce an extended version of the formalism of symbolic graphs, which encompasses types as well as attributes, for representing states of dynamic systems. Relying on this extension of symbolic graphs, we present a novel formalism of timed graph transformation systems (TGTSs) that supports the model-based development of dynamic real-time systems at an abstract level where possible state changes and delays are specified by graph transformation rules. We then introduce an extended form of the metric temporal graph logic (MTGL) with increased expressiveness to improve the applicability of MTGL for the specification of timed graph sequences generated by a TGTS. Based on the metric temporal operators of MTGL and its built-in graph binding mechanics, we express properties on the structure and attributes of graphs as well as on the occurrence of graphs over time that are related by their inner structure. We provide formal support for checking whether a single generated timed graph sequence adheres to a provided MTGL specification. Relying on this logical foundation, we develop a testing framework for TGTSs that are specified using MTGL. Lastly, we apply this testing framework to a running example by using our prototypical implementation in the tool AutoGraph.

     

The changing usage of a mature campus-wide wireless network

Wireless Local Area Networks (WLANs) are now commonplace on many academic and corporate campuses. As “Wi-Fi” technology becomes ubiquitous, it is increasingly important to understand trends in the usage of these networks. This paper analyzes an extensive network trace from a mature 802.11 WLAN, including more than 550 access points and 7000 users over seventeen weeks. We employ several measurement techniques, including syslog messages, telephone records, SNMP polling and tcpdump packet captures. This is the largest WLAN study to date, and the first to look at a mature WLAN. We compare this trace to a trace taken after the network’s initial deployment two years prior.We found that the applications used on the WLAN changed dramatically, with significant increases in peer-to-peer and streaming multimedia traffic. Despite the introduction of a Voice over IP (VoIP) system that includes wireless handsets, our study indicates that VoIP has been used little on the wireless network thus far, and most VoIP calls are made on the wired network.We saw greater heterogeneity in the types of clients used, with more embedded wireless devices such as PDAs and mobile VoIP clients. We define a new metric for mobility, the “session diameter”. We use this metric to show that embedded devices have different mobility characteristics than laptops, and travel further and roam to more access points. Overall, users were surprisingly non-mobile, with half remaining close to home about 98% of the time.     

Real-World Ubicomp Deployments: Lessons Learned

Among the many branches of computer science, ubiquitous computing enjoys an unusually distinguished history of creating and deploying prototypes. Why is this? A tempting answer is that many ubicomp researchers and practitioners have backgrounds in subjects such as HCI and systems--areas with a strong focus on learning from deploying working prototypes. However, a more compelling answer might be that ubicomp, unlike almost every other subspecialty with the exception of HCI, is about embedding computing into existing human systems. This introduction is part of a special issue on Real-World Deployments.     

Understanding privacy regulation in ubicomp interactions

Ubiquitous computing contains a huge promise for more intelligent services that are available anywhere and are able to dynamically adapt to the users’ current context. However, what necessarily follows such an environment is the compromising of the users’ privacy. We aim at analyzing this complex issue by applying and extending Altman’s theoretical privacy framework, well known in social sciences, to privacy in ubicomp. Altman understands privacy as a two-way interactive process, which makes the approach promising in analyzing ubicomp where people, devices and the environment interact with each other. We point out similarities between the existing model and the features of ubicomp environment, and verify the results by applying and analyzing the resulting extended framework to typical ubicomp use cases. Based on the analysis, we argue that privacy in ubicomp can be modeled similarly to privacy in general by extending the model to cover such factors as mediation and non-human actors.

并发系统中谓词行为图的行为时序逻辑表达

行为时序逻辑(TLA)组合时序逻辑与行为逻辑, 可以对并发系统进行描述与验证, 它引入动作和行为的概念, 使得系统和属性可用它的规约公式表示, 但存在用TLA描述复杂系统时TLA公式复杂且难以理解的不足。类似于状态转移图, 对于并发转移可以用谓词行为图进行图形化表示, 谓词行为图与行为时序逻辑规约具有相同的表达能力。介绍行为时序逻辑的语法、语义及简单推理规则, 用一个简单的实例说明使用谓词行为图去描述并发转移系统的有效性, 并用系统规约的TLA公式对谓词行为图表达能力进行证明, 表明两者具有等价性, 为描述和分析并发转换系统提供了一种可行的方法。     

Designing dynamic English: a creative reading system in a context-aware fitness centre using a smart phone and QR codes

Abstract

This article describes the design and development of a context-aware ubiquitous learning (u-learning) system for users to increase fitness-related reading comprehension in a fitness centre. With the use of mobile devices and sensing technologies, practitioners and researchers of ICT and ubiquitous computing (ubicomp) are paying attention to the planning and use of u-learning components to provide users more interactions with authentic learning objects in a real context. Meanwhile, English for specific purposes (ESP) with interaction design has been a focus in recent years; however, few ESP practitioners and researchers have explored fitness-related English with ubicomp. All of the users were satisfied with the use of the smart phones and scanning of QR codes on the machines in the fitness centre to develop their reading comprehension of fitness-related English. Finally, a learning design model for Fitness English reading with u-learning components was developed and elaborated from designers' perspectives.     

Analysis and identification of speed-independent circuits on an event model

The object of this article is the analysis of asynchronous circuits for speed independence or delay insensitivity. The circuits are specified as a netlist of logic functions describing the components. The analysis is based on a derivation of an event specification of the circuit behavior in a form of a signal graph. Signal graphs can be viewed either as a formalization of timing diagrams, or as a signal interpreted version of marked graphs (a subclass of Petri nets). The main advantage of this method is that a state explosion is avoided. A restoration of an event specification of a circuit also helps to solve the behavior identification problem, i.e., to compare the obtained specification with the desired specification. We illustrate the method by means of some examples.     

Enabling user-oriented management for ubiquitous computing: The meta-design approach

This paper presents iPlumber, a user-oriented management system for ubiquitous computing environments. Different from previous low-benefit “zero-configuration” systems or high cognitive-cost “end user programming” tools, our work attempts to attain a better balance between user benefits and cost by exploring the meta-design approach. A set of typical management activities in ubicomp environments are supported, from basic-level software sharing, foraging, and low-cost software configuration to advanced-level cooperative software co-design and error handling. These activities are elaborated through a smart home control scenario. The usability of our system is validated through an initial user study with a total of 33 subjects to test the management activities from an open exhibition environment and a controlled university environment.     

Minimizing security risks in ubicomp systems

In the Internet's early days, few people foresaw the emergence of spam, phishing schemes, and malware such as viruses, worms, Trojan horses, spyware, and key loggers that plague users today. It's safe to assume that ubicomp technologies will suffer from the same sorts of unforeseen vulnerabilities that have plagued the Internet. We can't account for every possible security and privacy risk in ubiquitous computing systems. We can, however, design such systems to reduce the burden on users as well as develop better security models and interaction techniques to prevent and minimize foreseeable threats.     

QoS management in heterogeneous home networks

An OSGi (Open Services Gateway Initiative) home gateway system manages the integration of heterogeneous home networks protocols and devices to develop ubiquitous applications. Wired and wireless heterogeneous home networks have different QoS concerns. For instance, jitter and latency are important concerns in web phones, while packet loss ratio is important in on-line video. This study adopts UPnP QoS specification version 1.0 to design an adaptive QoS management mechanism based on the RMD (Resource Management in DiffServ) architecture. This study monitors real-time network traffic, and adaptively controls the bandwidth, to satisfy the minimum but most important quality for each application in home network congestion. Simulation results indicate that the average jitter, latency and packet loss are reduced by 0.1391 ms, 0.0066 s, and 5.43%, respectively. The packet loss ratio is reduced by 4.53%, and the throughput is increased by 1.2% in high definition video stream; the packet loss ratio is reduced by 1.89% for standard definition video stream, and in VoIP (Voice over IP) the jitter and latency are reduced to 0.0407 ms and 0.0209 s, respectively.     

Rapid prototyping and user-centered design of interactive display-based systems

Much work on display-based ubicomp systems (and rapid prototyping in general) focus on producing proof-of-concept demonstrators, usually to gauge technical feasibility and collect initial user feedback. In our work, we've found that it's often equally important to investigate factors such as use and appropriation and that in some cases, without user studies, technical feasibility can be meaningless. We used rapid prototyping combined with a phased, iterative, and user-centered design approach to develop five display-based ubicomp systems for real-world use over time. In this article, we discuss our aims, approach, and lessons learned. The ubicomp systems that we developed and deployed use rapid prototyping techniques and a user-centered design approach.     

Supervisor Synthesis for Real-Time Discrete Event Systems

This paper introduces a formal framework to logically analyze and control real-time discrete event systems (RTDESs). Time Petri nets are extended to controlled time Petri nets (CtlTPNs) to model the dynamics of RTDESs that can be controlled by real-time supervisors. The logical behaviors of CtlTPNs are represented by control class graphs (CCGs) which are untimed automata with timing and control information in their state transition labels. We prove that the CCG corresponding to a CtlTPN expresses completely the logical behavior of the CtlTPN. The real-time supervisor is based on a nondeterministic logical supervisor for the CCG, including the delay for control computations to ensure the supervisor is acceptable in a true real-time environment. We prove the existence of a unique maximal controllable sublanguage of a given specification language and present an algorithm to construct the sublanguage. We also prove that the real-time supervisor meets the prespecified real-time behavior and present an online control algorithm to implement real-time supervisors. The concepts and algorithms are illustrated for an example of packet reception processes in a communication network.     

分布式网络管理系统中SNMP的开发与实现

SNMP简单网络管理协议广泛应用在基于TCP/IP网络的分布式系统中,用来实现获取和设置分布式环境中代理端的信息,以实现对分布式系统的有效管理。本文讨论了SNMP中的实体结构和开发过程等问题,在被管理的实体中,通过代理进程获取本实体的状态等信息,再发送给指定的管理站软件,也可用通过trap方式将本身的改变信息发送给管理站软件;在管理端的软件中,通过SNMP在网络上任何地方获取所有支持简单网络管理协议的网络节点的信息,并且对其进行远程管理和控制。     

Context sharing in a ‘real world’ ubicomp deployment

While the application of ubicomp systems to explore context sharing has received a large amount of interest, only a very small number of studies have been carried out which involve “real world” use outside of the lab. This article presents an in-depth analysis of context sharing behaviours that built up around use of the Hermes interactive office door display system received during deployment. The Hermes system provided a groupware application supporting asynchronous messaging facilities, analogous to a digital form of Post-it notes, in order to explore the use of situated display systems to support awareness and coordination in an office environment. From this analysis we distil a set of issues relating to context sharing ranging from privacy concerns to ease of use; each supported through qualitative data from user interviews and questionnaires.