Ubiquitous Computing Systems

Transcription

1 SeoulTech UCS Lab st Ubiquitous Computing Systems JeongKyu Lee

2 목차 Ubiquitous Computing Systems 1. Introduction 2. Ubicomp Systems Topics and Challenges 2.1 Resource-Constrained Devices 2.2 Volatile Execution Environments 2.3 Heterogenous Execution Environments 2.4 Fluctuating Usage Environments 2.5 Invisible Computing 2.6 Security and Privacy 2.7 Summary 3. Creating Ubicomp Systems 3.1 Why Duild Ubicomp Systems? 3.2 Setting Your Objectives 3.2.1Testing Your Ideas 3.3 Designing Good Systems Computational Knowledge of the Physical World Seamfulness, Sensibility, and Tolerant Ignorance User Mental Model and Responsibility It Is Always Runtime Handling Transient Connections The State of the World Is It Working? 3.4 Summary 2

3 1. Introduction 1.1 Ubiqutious Computing : Simple and safe anywhere get on necessary information from a variety of networking. Definitions - researcher in the Computer Science Lab at Xerox s PARC (Palo Alto Research Center) - first articulated the idea of ubiquitous computing in Medals for all objects inserted into intelligent computing capabilities 3

4 1. Introduction 1.1 Ubiqutious Computing Ubicomp is a post-desktop model of human computer interaction in which information processing has been thoroughly integrated into everyday objects and activities. Integrate computers seamlessly into the world invisible, everywhere computing. Often called pervasive/invisible computing. Computers are mostly not invisible, they dominate interaction with them. Ubicomp is about making computers invisible. 4

5 1. Introduction 1.1 Ubiqutious Computing Definitions Ubiquitous Computing Virtual Reality Physical space + Electronic space Real Environment Ubiquitous Computing Environment 5 Virtual Environment

6 1. Introduction 1.2 Ubiqutious Computing Requirement (5C, 5A) Communication 6

7 1. Introduction Ubiquitous computing Mobile computing Intelligent environment. Technology View Computers everywhere embedded into fridges, washing machines, door locks, cars, furniture. Intelligent environment. Mobile portable computing devices Wireless communication seamless mobile/fixed. User View Invisible implicit interaction with your environment. Augmenting human abilities in context of tasks 7

8 1. Introduction 1.3 Ubiqutious Computing Characters - Mark Weiser (1952~1999) Characteristics Connected Invisible/Pervasive Calm Technology AnyTime, AnyWhere Description Interconnected in any network all objects are to exchange information. Invisible interface. Personalised service. Intelligent computer provides services to meet the user's own environment. Overcome the limitations of time and space. Possible to use a computer anywhere in the real world. 8

9 1. Introduction 1.3 Ubiqutious Computing Character Technology Device Technology Network Technology Sensing Technology Context awareness Technology Interaction Technology Security Technology Description IT SoC(System on Chip), MEMS, Nano Technology(NT), Battery BcM, IPv6, Wireless, Blue tooth, Grid, etc. RFID Technology, Sensor Network - Users and a user wants to recognize information on the environment type, - Context definition and representation techniques (Semantic Web) - Middleware for the delivery status information More convenient computing environment through the realization of human-centered user interface DRM(Digital Right Management) AAA(Authentication, Authorization, Accounting) Security Protocol technology 9

10 2. Ubicomp Systems Topics and Challenges 2.1 Resource-Constrained Devices (1/2) Moore s law has resulted into highly powerful PCs Fast CPUs Large memory sizes High network bandwidth Many UbiComp devices like PDAs, smart-phones, music players etc have significantly less resources than PCs Resource-aware computing An approach to develop technologies where the application is constantly notified about the consumption of vital resources, and can help the application (or the user) to take a decision based on available resources now and in the future 10

11 2. Ubicomp Systems Topics and Challenges 2.1 Resource-Constrained Devices (2/2) Examples Media streaming adjusted to available network bandwidth/battery Display brightness adjusted to prolong battery life Most constrained resources Energy One of the main hardware constraints to consider when building UbiComp systems and applications is power consumption and/or opportunities for energy harvesting including recharging Foraging: Collecting energy from the environment (e.g. kinetic energy from a walking person) Cyber foraging: Offloading resource-heavy tasks (e.g. to dedicated or shared servers) 11

12 2. Ubicomp Systems Topics and Challenges 2.2 Volatile Exrcution Environments (1/2) Service discovery Technology and standards enabling devices to discover each other, set up connections and start using each other s services Example: When a small portable device enters a smart space it might want to start using its displays, printers, etc Existing technologies Jini, UPnP Bonjour/Multicast DNS (mdns) Bluetooth discovery protocol Limitations Still, all these technologies fail to enable discovery beyond LANs Cumbersome use (e.g. Bluetooth need for PIN number) 12

13 2. Ubicomp Systems Topics and Challenges 2.2 Volatile Exrcution Environments (2/2) UbiComp and Distributed Systems Spontaneous changes Viewing UbiComp from a Distributed Systems perspective, the most important challenge is that of spontaneous changes: Mobile devices might appear or disappear without warning (because of physical movement, battery depletion, network error, etc) Appropriate handling of such spontaneous disconnections us needed More volatility factors exist, such as changes to the network topology Volatility in Distributed System While volatility is a known problem also for traditional distributed systems, UbiComp differs in that the connectivity changes are common rather than exceptional, and often of a more basic nature 13

14 2. Ubicomp Systems Topics and Challenges 2.3 Heterogeneous Execution Environments (1/2) Heterogeneity A UbiComp application also involves a wide range of possibly heterogeneous hardware and software: Devices and hardware components Network technology Operating Systems Input/Output capabilities Resources Sensors 14

15 2. Ubicomp Systems Topics and Challenges 2.3 Heterogeneous Execution Environments (2/2) UbiComp Applications Unlike traditional applications, in UbiComp applications do not reside on one or two at most computers but rather span several devices which need to closely coordinate their operation in order to make up the application 15

16 2. Ubicomp Systems Topics and Challenges 2.4 Fluctuating User Environments (1/2) Contemporary Computing - Users use PCs for information access on a one-to-one relationship Ubiquitous Computing - The same device might be used by several users and a user might use several devices - Many-to-many relationship between users and devices - Doing a task is no longer tied to one device, but rather it is distributed across several heterogeneous devices Challenges - Technology is overwhelming users with the need to set up and manage - Calm technology and invisible computing is the opposite of that 16

17 2. Ubicomp Systems Topics and Challenges 2.4 Fluctuating User Environments (2/2) Changing location of users Location-based computing Example: Tour guides Varying user context Context-aware computing Includes information about who is using the application, who is nearby, ambient environment details, etc Example: A smart conference room which adjusts temperature, lighting and whiteboard contents based on the users present Fluctuating user activity Activity-based computing Example: Smart hospital where personnel need to coordinate their activities based on the multiple patients they are attending to 17

18 2. Ubicomp Systems Topics and Challenges 2.5 Invisible Computing (1/2) One of the core elements of Weiser s vision of UbiComp Example: A smart home that transparently monitors its users so that It can automatically adjust the heating/ventilation/air conditioning The computers are invisible to the users in a double sense 1. The computers are embedded into buildings, furniture, medical devices, etc physical invisibility 2. The computers operate in the periphery of the users attention and are hence imperceptible mental invisibility Why is invisibility a major departure from traditional computing? Because traditional systems rely heavily on having the users attention explicitly 18

19 2. Ubicomp Systems Topics and Challenges 2.5 Invisible Computing (2/2) Challenge: Invisible Computing Significant research effort towards invisible computing Autonomic computing Systems that are capable of self-management Example: Mainly, cluster-based server architectures Proactive computing Anticipate failures and prepare for exception handling Example: Offload a mobile agent when a device s battery is running out or proactively download resources before leaving network coverage Graceful degradation Computers should not depend on volatile resources (such as networking) and be prepared to operate also when some are unavailable 19

20 2. Ubicomp Systems Topics and Challenges 2.6 Security Interactions will be cross multiple organisational boundaries specification, analysis and integration for heterogeneous OS, databases, firewalls, routers. Everything worth hacking gets hacked. Need for secure out of the box set up that can identify friend or foe level of trust. Small communicators, with confidential data, are easily lost or stolen biometric authentication. Necessary security technology exists. 20

21 2. Ubicomp Systems Topics and Challenges 2.6 Privacy Location service tracks movement to within metres. Clearly indicate you are being sensed or recorded + user control to stop recording or control distribution of information. You are now predictable System can co-relate location, context and behaviour patterns Do you want employer, colleagues or insurance company to know you carry a medical monitor? Tension between authentication and anonymity business want to authenticate you for financial transactions and to provide personalized service web sites. Constant spam of context dependent advertising 21

22 2. Ubicomp Systems Topics and Challenges Ubiquitous/Pervasive Computing Focus usually on technical challenges Other challenges: design challenges, human-computer interaction, real-time deployment, etc. Builds on previous work in the areas of - Distributed Systems - Mobile Computing 22

23 2. Ubicomp Systems Topics and Challenges Challenges What are some of the challenges in UbiComp systems research? How to design hardware and Operating Systems for sensors and embedded devices? How to allow devices to find one another and use the services of each other? How to support resource impoverished devices that run on batteries? How to enable seamless mobility and collaboration in smart spaces such as smart rooms and hospitals? Overlap with other systems research questions But unique set of challenges in UbiComp systems 23

24 2. Ubicomp Systems Topics and Challenges Nanotechnology (1/2) The trend toward miniaturization of computer components down to an atomic scale is known as nanotechnology 24

25 2. Ubicomp Systems Topics and Challenges Nanotechnology (2/2) Mobile data technology GSM, GPRS, UMTS, CDMA, WAP, Imode Wireless data technology Bluetooth, b Internet data technology IP over optical, Broadband Content services Web & WAP Applications Multimedia, Internet messaging 25

26 3. Creating Ubicomp Systems 3.1 Why Bulid Ubicomp Systems? Prototyping future systems to explore ubiquity in practice Empirical exploration of user reactions to ubicomp Gathering datasets to tackle computational problems relating to ubicomp Creating ubicomp experiences for public engagement or performance Creating research test beds to agglomerate activity and stimulate further research To explore a hypothesis concerning ubicomp more naturalistically To test the limits of computational technologies in a ubicomp setting Addressing the perceived needs of a problem domain or pressing societal issue 26

27 3. Creating Ubicomp Systems 3.2 Setting Your Objectives Testing Your Ideas Low-fidelity prototypes, which can be simple scenarios that can be discussed, paper prototypes, or even models of devices or graphical story boards of proposed interactions anything that can add richness to the discussion of the system with potential users. Video prototypes, although considerably requiring more effort to create, can communicate the concepts in the system quite effectively and act as a useful reference for explaining the system later on. Rapid prototypes of user interfaces using prototyping toolkits (see Section 2.6) can afford a more realistic synthesis of the intended user experience. Wizard of Oz prototypes of parts of the system may allow the final behavior of the system to be emulated and thus experienced by others. 27

28 3. Creating Ubicomp Systems 3.3 Designing Good Systems Computational Knowledge of the Physical Word From a systems design perspective, it is far from clear what the interfaces and internals of a ubicomp system should be, necessitating an experimental approach. 1. What can be reliably sensed 2. What can be reliably known? 3. What can be reliably inferred? 28

29 3. Creating Ubicomp Systems 3.3 Designing Good Systems Seamfulness, Sensibility, and Tolerant Ignorance Pessimistic: Only show information that is known to be correct Optimistic: Show everything as if it were correct Cautious: Explicitly present uncertainty Opportunistic: Exploit uncertainty (cf. Gaver et al., 2003) 29

30 3. Creating Ubicomp Systems 3.3 Designing Good Systems User Mental Model and Responsibility The frequency or inconvenience of potential user involvement The severity or undesirability of the consequences if the system gets it wrong The reliability of detecting the appropriate moment and appropriate action The acceptability to the user of automating the behavior 30

31 3. Creating Ubicomp Systems 3.3 Designing Good Systems It Is Always Runtime 1. Systems requiring a carefully contrived startup order are likely to fail. 2. If the availability of elements may be sporadic, your system should be able to gracefully handle disconnection and reconnection or rebinding to alternate services. 3. Assume that individual components may fail or be temporarily isolated (which is especially true of so"ware elements on mobile devices) and design your system accordingly so that state can be recovered. 4. Decide proactively how to handle data when an element is disconnected: are the data kept (e.g., bu#ered) until reconnection, and if so, how much will you bu#er before discarding. What strategy will you choose to decide which data to keep or discard (oldest, f reshest, resample, etc.)? 5. Consider including version information in protocols used in systems designed to run longitudinally to at least identify version mismatches. 31

32 3. Creating Ubicomp Systems 3.3 Designing Good Systems Handling Transient Connections - Network connections (or the lack or failure thereof) can have profound effects on the performance of ubicomp systems and, crucially, the end user experience Handling Transient Connections - Transient connections and component failures have an impact on how consistent the state of your overall system will be. It is important to design in strategies for recovering from both of these cases. Parts of your system may be replicable or sufficiently available to use wellknown techniques to mask such failures and achieve some degree of fault tolerance. However, in many ubicomp systems, software components are often intimately linked to specialist or personal hardware, or may be placed in unique locations, which makes traditional techniques involving redundant replication or fail-over inappropriate. 32

33 3. Creating Ubicomp Systems 3.3 Designing Good Systems Is It Working? Use of conventional mechanisms such as log files and network packet tracing to passively monitor running components Including status protocol messages that can be intercepted (often as periodic heartbeat messages) Adding status displays including use of hardware such as LED blink sequences, audible and visual feedback Including diagnostic interfaces such as embedded web servers that can be interrogated Enabling remote access to components such as remote shells, etc. Externalizing of state or communications by using a middleware such as a publish-subscribe event channel, Tuple Space, Message Oriented Middleware, etc. 33

34 3. Creating Ubicomp Systems Management Huge, complex systems - Billions of processors - Multiple organisations - Managing physical world, controlling sensors, actuators Hacker and virus paradise System propagates false information about individuals or organisation. Complexity of s/w installation on a workstation or server how do you cope with billions? 34

35 3. Creating Ubicomp Systems Proposed Management Solution Intelligent agents, mobile agents, policy. QoS Management Fat pipes and large storage can convert media streams to short traffic bursts in core network but still needed for wireless links. Adaptive self-management is the only answer Partitioned domains of responsibility Genetic algorithms may be suitable for long-term strategy but need more deterministic solutions for short term decision making 35

36 Reference John Krumm Ubiquitous Computing Fundamentals Weiser, Gold and Brown The origins of ubiquitous computing research at PARC in the late 1980s IBM Systems Journal, VOL 38, NO 4,

37 Q & A 37

38 Thank you 38