Glossary of Terms from the Book, Ubiquitous Computing; Smart Devices, Environments and Interactions

(Only for chapters 1 and 3 so far, last update 14/08/2013); this is work in progress. Please reference the book if using these definitions of terms in another publication)

1-tier or single tier system or monolithic system is a single collection of components that cannot be partitioned or distributed. This has advantages and disadvantages.

Abstractions define those things that are important in a system and hide or make transparent those properties that are not. Abstraction is a model to reduce system complexity using system architectures focus on reducing system complexity, simplification of the system, through using modularisation & transparency.

Abstractions make transparent (hide or mask) properties not needed by external interactions. Abstraction that simplifies the view or access to internal functionality to the outside is also called an interface.

Access transparency is where the details of system access is hidden from user(s)

Accompanied devices are ICT devices that are carried in different ways, e.g. in accessories that are carried, hand-held,

Active context awareness by a system is the system automatically adapts to the context on behalf of users

Adaptive systems are active context-aware Systems actively adapt to context changes in a dynamic environment rather than just present context changes to the user (Section 7.2.4)

Affective, emotive Computing is computing that relates to, arises from, or influences human emotions. This is also considered to be a sub-type of human intelligence (Section 5.7.4)

Agent, see intelligent system

Ambient Intelligence (AmI), is similar to UbiCom, means intelligence everywhere. There are 5 key features for AmI to be embedded, context-aware, personalised, adaptive and anticipatory (Arts and Marzano, 2003)

Anticipatory, speculative, proactive systems improve performance and user experience through anticipated actions and user goals in relation to current context, past user context and group context. This overlaps with user context-awareness (Sections 5.6 and 7.2)

Appliance is a 1-tier system, a single computer node, or device that performs a single specific service. Appliances traditionally use on embedded system design to execute single fixed task execution.

Asynchronous I/O can be used to support volatile service invocation design. This is based upon using buffers at the sender-side or receiver-side or both.

Automatic system is on that operates without human intervention (Section 10.2.1.1)

Autonomic, self-managing, self-star system is able to support various self-star properties such as self-configuring, self-healing, self-optimising and self-protecting behaviour (Section 10.4)

Autonomous system is one that acts proactively, automatically to achieve its system goals or functions. It can be autonomic, i.e., is Self-managing (supports one or more of the self-star or self-*properties. It enables humans to be able to delegate high-level goals rather than low-level tasks to it.

Basic I/O System (BIOS): often when a computer is started or booted, also called bootstrapped, software is loaded in stages. First, BIOS or Basic Input-Output System, a type of firmware, is loaded. This is used to load the operating system kernel. BIOS initialises several key hardware components and peripherals such as CPU, (primary) memory, graphics controller, etc.

Blackboard is a type of Shared Data Repository that represents and stores data created and used by other components. Data is input a repository from data producers. Data is output from a repository to data consumers.

C2C is automated and autonomous ICT-ICT system interaction, with minimal human involvement.

C2C is automated interaction between computers independent of physical environment (to an extent). It is a Virtualisation of reality facilitated by C.

C2H is interaction in which C is aware of context of H & adapts to it. C observes and models human interaction, i.e., active personalisation. Synonyms are implicit HCI or iHCI

C2P is ICT system interaction with the Physical Environment (P) that is P Context-aware. C augments or mediates reality of P. C actively adapts to context of P. Synonyms are Augmented Reality and Mediated Reality

Cache-hit: the information requested is stored in the read-ahead buffer

Cache-miss: the information requested is not stored in the read-ahead buffer

Calm computing is where ICT is nonintrusive and invisible to the user. It is integrated into the general ecology of the home or workplace and can be used intuitively by users (Section 5.7)

Canonical or common exchange data format is used between heterogeneous senders and receivers; each converts any data for exchange to a common format.

Choreographed services are where multiple interactions across multiple services occur but allow some freedom of interaction by participants (choreographed) or constrained by the use of some common entity or resource (mediated) (Sections 3.3.2, 9.2.2).

Client Server model: this is an asymmetric distributed computing model with respect to where resources reside and the direction of the interaction. Servers are resource rich. Clients (access devices) are relatively resource poor. Clients have a reliance on high available links for on-demand access to resources of servers. Client processes initiate the interaction whereas service processes on wait for client requests

Competitive, self-interested, antagonistic, adversarial systems are where Individual agents and organizations have private goals and utility functions. They seek to achieve in a multi-entity setting without requiring collaboration Entities could also act malevolently (Section 9.2.4)

Component or module or resource is part of a system that performs one or more well-defined (service) functions or services (actions) that can be designed to be loose-coupled with other components.

Computational Grids: higher aggregate computational capacity available for single applications; Grid capacity can hence exceed capacity of any single machine

Context adaptation, see context-aware

Context aware is where a system of one or more devices modifies its behaviour based upon awareness of the context and in particular its awareness of significant context changes.

Context can be defined as one of the environment situation state for the Physical Environment ( location, time, temperature, rainfall, light level etc.); Human Context (or User context or person context): interaction is usefully constrained by the identity of users; preferences; task requirements, etc.

Context-aware systems are systems can discover and take advantage of the situation or context such as: location, time and user activity. There are three main subtypes of context-awareness; physical-world, user and virtual (ICT) device awareness. Synonyms are Sentient, unique, localized and situated.

Cooperative, collaborative, benevolent system is where multiple agents (or multiple intelligent systems) can share tasks and information in order to achieve shared goals (Section 9.2.3)

Data Grids: infrastructure to synthesizing new information from distributed data repositories, e.g., data warehouses

Delayed Write is a design to enable Volatile Service Invocation. Here, updates are made to the local cache whilst services are unreachable which must be later reintegrated upon reconnection.

Devices refer to some set of system hardware and software ICT resources or components. This set is usually static fixed at design time. Dynamic component-oriented resource replacement and plug-ins (Plug and play) may be supported in some devices. Devices may support remote external service access. Devices may support local, internal service execution. Devices access specific external ICT environments or infrastructure.

Disappearing computer is a device that is too small to be visible or embedded or is visible but not noticeable, is a part of peripheral senses. Synonym is for Calm Computer

Distributed System is system of networked ICT devices that support access transparency and openness

Domain Name Service, DNS, maps IP addresses to address names and vice versa.

Dynamic Host Control Protocols, DHCP, used to dynamically assign addresses of new devices in a LAN. Device asks a DHCP server for an IP address. Addresses are leased for use from the server for a given time.

Embedded devices are incorporated into larger objects or systems to enhance them.

Embedded, encapsulated, embodied System is where input-output and computation is completely encapsulated by, or contained in, the device it controls, e.g., a system that acts as a self-contained appliance (Section 6.5)

Embodied Device is aware of its environment and the services it can access. It is bounded by its physical and ICT environment.

Embodied Reality is the opposite of VR (people in virtual world)

Emergent Organizations lead to levels of interaction that are not level of the individual interactions (Section 9.2.3.3)

Emergent, self-organising systems where more complex behaviour can arise out of multiple simple behaviours (Section 10.5)

Enterprise Service Bus or ESB supports messaging, Web Service integration, data transformation and intelligent application level routing for SOC. It decouples service provision from service access.

Environment-aware or physical context-aware systems are aware of the physical environment situation. Physical context-awareness includes spatial and temporal awareness (Sections 7.4, and 7.5)

Event is some significant data exchange that caused a significant change in system state, e.g., a flat-tyre triggers a vehicle driver to slow down. Events may be time-based, can be triggered by external environment, may be rule based, etc.

Event-Driven Architectures or EDA is an important design for SOC and MOM Architectures. Here data or message exchanges are in the form of events. Event is some input such as a message or procedure call of interest. Also referred to as Publish-and-Subscribe interaction

Explicit HCI (eHCI) is explicit, low-level device, artificial human, computer interaction such as keyboard or mouse.

Fat client (server model): suitable when access devices have a higher system spec. than thin client (access) devices and can operate when a limited network connection is available. This model may offload some of processing and storage from the server into the access device depends on application.

Firmware is a type of low-level software to control hardware. It is a basic computer program that resides in special hardware, typically in ROM, EEPROM or flash memory.

Grid computing and cloud computing is a type of distributed systems that enables large-scale coordinated use and sharing of geographically distributed resources, based on persistent, standards-based service infrastructures, often with a high-performance orientation (Foster et al., 2001)

H2C or explicit (e)HCI is interaction in which humans (H) use a model of ICT or computer systems (C) in order to explicitly interact with it. H can explicitly personalise and customise C

H2H or human to human interaction is interaction not mediated via ICT systems, e.g., talking

Handheld device is oriented to 1-handed and hands-free, have lower ICT resources.

Heterogeneous systems are able to operate across different homogeneous environments, seamless integration of devices and environments, taking on new contexts when new resources become available (Sections 3.2, 3.3)

Human Context (or User context or person context) is used in interaction that is usefully constrained by identity of users; preferences; task requirements, etc.

Hybrid P2P networks: client-server organisation used for specific tasks and interactions, i.e., services discovery; P2P organisation used for service invocation. e.g., Napster.

ICT awareness: Awareness of ICT infrastructure in which an UbiCom system exists, e.g., awareness of network QoS when transmitting messages (Section 7.6)

ICT Context or Virtual Environment Context is a UbiCom system that is aware of the services available that are available internally and externally, locally and remotely.

ICT Context or Virtual Environment Context is the state of the distributed system of devices.

Idempotent messages can be repeated, at least once, without side-effects, e.g., pressing an elevator call button again while waiting for it to arrive. This can be used to support a volatile service invocation design.

Immersed, virtual, mediated reality, Sense of presence is where a person is in a real-time interactive environment which experiences an extended sense of presence that combines the virtual and the real, often by overlaying virtual views on real views (Section 5.4.4)

Implanted devices inside humans augment the physical (and mental?) into unhealthy (and healthy?) humans, e.g., heart pacemaker

Implicit (iHCI) HCI use more natural and less conscious interaction; the device anticipate use reduces explicit user interaction

Information appliances are (tab or pad) sub-types of smart devices

Integration of services generally means that individual systems of components become statically linked, perhaps by combining data and code into a single whole repository, hence losing some of their autonomy.

Intelligent agent, see intelligent system

Intelligent System is a system whose action selection can be based upon a combination of Reactive or Reflective, Model-based, Rule/Policy-based, Logic/Reasoning or Goal-oriented. Synonyms are AI, agent-based system etc. An intelligent system can be composed or more than one intelligent system. This is referred to as Distributed AI, Multi-Agent Systems, Collective or Social Intelligent system that supports a cooperative and or competitive interaction between systems.

Interface of a system or system component is a system abstraction that simplifies the view or access to internal functionality to the external entities that interact with the system or system component.

Interoperability of services enables services to remain autonomous but to dynamically link to each other, to allow them to exchange data in a format that both understand. Distributed systems that interoperate can exchange data in a variety of data formats, encodings, etc.

Layered model: high-level service interfaces hide details of lower level ones from higher ones; is often used in network software or service design.

Learning, adaptive Systems can be designed to improve their own performance (Section 8.3.6)

Link-local Multicast Name Resolution (LLMNR) from Microsoft is another network address assignment protocol.

Loose-coupling of a system component means that the component can flexibly interoperate with many other components. This promotes horizontal interoperability between system components in different or heterogeneous application domains.

Luggable devices are oriented to 2-handed operation, use higher ICT resources

Macro-Kernel (Monolithic Kernel) is a design of an OS where all the management is done in one single large entity called the Kernel or core, i.e., Hardware related device drivers, memory management, process support, process Scheduling, Network protocol stack, file system, etc.

Memory Management (MM) is an OS kernel function that manages applications use of memory or the data and code address space in the main primary physical memory (RAM). OS kernel defines a separate region of address space for each process. If processes require more memory than the size of the primary memory (RAM), primary memory is mapped to secondary memory (e.g., hard disk)

Micro-Kernel is a design of an OS where only fundamental parts of the OS management are performed by it, in the kernel, such has memory management, Process support, Scheduling, power management. Some other OS management tasks, e.g., File system, Protocol stack etc., are performed as user level processes, outside the kernel.

Middleware is introduced in between applications and OS to simplify access to services. Middleware factors out set of generic services, e.g., database access, file system access etc. to make them application independent and OS independent.

Mobile system is where users, services, data, code and devices may be mobile (Sections 4.2, 11.7.5)

Model-based system is a system that uses a model of how itself operates and the how the world works (Section 8.3.3), There are many types of model representation such as rule-based, different types of logic-based, etc. goal-oriented, planned,

Modularisation of a system to simplify of a system is based upon two common criteria for modules (high cohesion performing well-defined functions), loose-coupling with low side-effects.

Multicast DNS (mDNS) from Apple allows a network device to choose a domain name in a local namespace and announce it using a special multicast IP address.

Multi-tier (3, 4 ... N-Tier) systems is were major system functions such as multiple application processing services, data management, data presentation are distributed on 3, 4 ... N different computer nodes.

Network discovery is used by when new devices are introduced into a network; may need to have a network address assigned to device itself as well as discovering the network addresses of others that the device needs to interoperate with.

Networked devices are interlinked using a network which is often wireless (Chapter 11). Multiple entity interaction can be coordinated synchronously or asynchronously over time and space interactions (Section 3.3.3.2)

Open system; New components can be introduced and accessed, old ones can be modified or retired. Components can be dynamically discovered (Section 3.3.2)

Openness: Allows systems to avoid having to support all its functions at design time, avoiding a closed implementation; Support different types of same function (heterogeneous)

Operating System (OS) is system software that controls and abstracts hardware. It manages resources and processes to support different applications. OS Kernel is a computer process that has privileged use of ICT resources (memory, CPU, Input Output (IO) etc.) to manage 3 main resources of a device: Processes (processing), memory (data storage), IO (communication). An OS enables user applications to become simpler and more device-independent.

Operating System Process Management is performed by the OS kernel to coordinate or schedule the use of CPU by multiple processes, i.e., sometimes the number of executable processes is greater than the number of CPUs available. It also manages inter-process communication. Types of process scheduling are pre-emptive, non-pre-emptive, etc.

Orchestrated services are where multiple interactions across multiple services can be controlled and ordered by designating some service leader (orchestrator) who acts as a central-planer.

Overlay (network) provides a logical view of the underlying physical network. Unstructured overlay networks, e.g., ad hoc networks are independent of any physical network topology and use decentralised and partially decentralised nodes. Structured overlay networks are dependent on the physical network topology of nodes and use hybrid decentralized nodes.

P2C is Physical Environment (P) interaction with simple ICT mediation (C). C Senses P. C is aware of Context of P but may not actively adapt to it.

P2P is Physical Environment (P) interaction with no ICT mediation (C).

Partial observability at sender / requester increases complexity, e.g., because a receiver cannot distinguish between crash before message is sent and a sent message being lost,

Partial P2P: Partially decentralized P2P systems where all nodes not equal, a few superpeers or supernodes are elected to operate as middleware or common used node, in part because they have high ICT resources, e.g., is used by Skype VoIP.

Peer-to-Peer Systems (P2P) can be defined as distributed systems consisting of interconnected nodes, able to self-organize into network topologies with the purpose of sharing resources such as content, CPU cycles, storage and bandwidth, capable of adapting to failures and accommodating transient populations of nodes while maintaining acceptable connectivity and performance without requiring the intermediation or support of a global centralized servers or authorities.

Person-aware systems are tailored to an individual user or type of user, based on personal details or characteristics that a user provides or is gathered about a user. This may trigger system adaptation (Sections 5.6, 5.7). Synonyms are user-aware, personalised, tailored

Post-human Sense of being in a world that exists outside ourselves, extending a normal experience of a person across space and time (Section 5.4.1)

Pre-emptive scheduler is a type of Operating System Process Management in which a static scheduler all runnable processes get fixed time-slot.

Priority scheduling is a type of Operating System Process Management in which runnable processes with a higher priority run first.

Proactive System or device is where user goals can be used to plan actions dynamically rather than pre-programmed actions (Section 8.3.4)

Process Virtual Machine or process VM is a virtual platform (actually itself another process) that executes (other) individual processes. High-level Language Process VM executes actions specified in some instruction language, e.g., Java VM.

Proxy (based Service Access): Some applications use a client proxy to simplify access processes in the client or service access device. Proxies represent a partitioning of the client into presentation (in the client) with processing and communication (in the proxy).

Publish-and-Subscribe interaction is similar to EDA. Some nodes publish events while others subscribe to being notified when specified events occur

Pull interaction: users or clients make requests, e.g., lookups to search or browse through lists of requests or capabilities previously announced to a directory

Pure P2P: no notion of fixed clients or servers, only of equal peer nodes that simultaneously functions as both dynamic servers and clients (called servents), e.g., Gnutella or Freenet

Push interaction, e.g., Bluetooth, users or clients receive service messages from senders (servers). Senders use broadcasts/multicasts to a number of unknown parties or previously registered interested parties.

Reactive, reflex system is a system whose environment events are sensed. Events then trigger action selection that may lead to actuators changing their environments (Section 8.3.2)

Read ahead is one design option to deal with volatile service invocation. Information is buffered, pre-cached in the (receiver) devices when the network is available.

Receiver or sender makes it right scheme, is used between heterogeneous senders and receivers, either the sender or receiver but not both converts any data for exchange to the data format the other can handle.

Remote Procedure Call or Remote Method interaction is a type of Distributed Service Invocation Model that hides distribution and the remote interaction, and makes it appear to be local, request reply based interaction.

Resource-constrained Systems are designed to be constrained in size to be portable or embeddable; to use constrained computation, data storage, input and output and energy (Section 13.5.2)

Semantic Web (SW) can be used to represent services, resources, etc., in terms of richer types of relationships between them such as classes and composition.

Service (Provision) Life-cycle has 4 phases: Creation, Execution (also called Operation), Maintenance and Dissolution

Service Choreography is a type of dynamic service composition that enables the individual services some flexibility in offering and coordinating their own service actions.

Service Competency is the ability to undertake the task correctly.

Service composition that is dynamic can be triggered to help enable on-demand service access. If a service does not exists it can be perhaps be created by combining two or more simpler services dynamically,, e.g., through sequencing different services.

Service Composition: Multiple services may need to be composed before used

Service Constraints or policies for a service, e.g., a service is only accessed at a physical location, from 9 AM to 5 PM.

Service creation: Service processes register in service directories. Service requesters in service access nodes or client, search or lookup or discover services. Services may get selected, configured. Multiple services may need to be composed.

Service Descriptions: (or specification) of some task is a set of one or more actions that are offered by providers to perform user task.

Service discovery, the scope of the discovery functions depends on the design and can include: Network discovery, Service name to address resolution, Service registration, Service queries to providers to match requests (pull) or service broadcasts (push) and lastly, Service selection.

Service dissolution: Services may be put off-line or Services may be terminated temporarily by the processes themselves or by requesters. Services may also be terminated permanently and removed. Hardware may need dissolution too.

Service Execution: actually performing the service on behalf of someone.

Service Grids: provide services not provided by any single machine.

Service is a system component and set of related system actions that are characterised or defined by one or more of the following: descriptions, service outcome, service offers, competency, constraints or policies.

Service matching or service lookups: can use different types of matching: exact-match, wild-card match, semantic match; white-page (name), yellow-page (service type), versus green-page.

Service Offers: (or tenders) are given by service providers to perform a task on behalf of someone else.

Service Orchestration is a type of dynamic service composition that uses a single entity, a manager or conductor, to direct the schedule of the actions of the individual services.

Service Outcomes: services are the means to achieve a defined result (the outcome).

Service processes are sequences of individual service actions that are scheduled for execution.

Service-oriented Architectures (SOA), also referred to as SOC (Computing) is where all system components are represented as services as computational or information processing components

Services of ICT systems are composed of one or more service (action)s. Core data or information services support information acquisition, processing, retrieval, storage, presentation, exchange & management. Services may be executed locally in clients or remotely in servers. Services are defined by service descriptions. Services may adhere to other properties such as policies, QoS, etc.

Shared Data Repository is a type of Distributed Service Invocation where participants communicate by leaving messages for others via some shared intermediary, e.g., electronic bulletin boards, knowledge-based black-board systems, RDBMS, etc.

Shared knowledge, Speech-act based, intentional, mentalistic systems are where multiple agents interact based upon propositional attitudes, i.e., relationships based upon beliefs, desires or wants and intentions3 (Section 9.3.3.4)

Smart access devices are a types of smart devices that have a range of forms with respect to size and 1D versus 2D versus 3D dimensions, e.g., dust, tabs (phones), pads (tablets, laptops), skins, clay and boards

Smart Boards are Meter sized displays and surfaces for collaboration

Smart Clay is an ensemble of smart dust (and smart skins?) can be formed into arbitrary three dimensional shapes as artefacts resembling many different kinds of physical object.

Smart DEI System Model, or Smart Devices, Environment and Interaction, is a model for UbiCom that supports the core internal system Ubicom properties (distributed, iHCI, context-aware, autonomy, intelligence ) to different degrees; it supports different types (phys. virtual, human) of external environment interaction to different degrees; Access Devices can be different form-factors (the six basic forms are tab, pad, board, dust, skin, clay) for devices. It supports 3 basic architectural design patterns for UbiCom smart Devices, smart Environments (are environments that can contain smart devices), smart Interaction (multiple systems can combined to form interacting systems of systems).

Smart devices are devices that support some (partial?) set of UbiCom properties.

Smart Devices can be characterised as a set of system hardware & software ICT resources. These resources can be static or fixed at design time and can support dynamic component-oriented resource extensions and plug-ins (Plug and play) of some hardware resource. It supports some local, internal autonomous service execution as well as access to specific external environments (human, physical world and distributed ICT). It supports one or more of the 5 core Ubicom system properties.

Smart Dust refers to MEMS (Micro-Electro-Mechanical System) ICT devices that are miniaturised, cheaply manufactured, without visual output displays, ranging from mm to nm. These can be embedded into 2D & 3D surfaces or scattered into 3D spaces.

Smart Environments is a physical environment consists of a set of smart devices specialised to interact within their physical and human environments. It is where computation is seamlessly used to enhance ordinary activities (Coen). It can acquire and apply knowledge about the environment and its inhabitants in order to improve their experience in that environment (Cook & Das). It typically is an embedded system. Devices maybe fixed versus anchored mobile versus unanchored or untethered mobile devices in the environment. Smart environment interaction can consist of tagging and annotating; sensing and monitoring, filtering, adapting, controlling, assembling and regulating the physical environment.

Smart Interaction is a type of design is needed to knit together many individual system components and interactions. Smart interaction promotes unified and continuous interaction model between UbiCom applications & their UbiCom infrastructure, physical world & human environments. Smart (system) extends basic interactions by supporting coordinated interaction, cooperative versus competitive interaction and/or policy and Convention based Interaction

Smart means systems are active, digital, networked, autonomous, reconfigurable, local control of its own resources, e.g., energy, data storage etc.

Smart Mobile Device is a multi-purpose ICT device, operating as a single portal to multiple remote versus local application services, e.g., personal computer, mobile phone, cameras, games consoles, etc. Its multi-functional support eases access & interoperability of multi-functions at run-time versus decreased openness of the system to maintain (upgrade) hardware components and to support more dynamic flexible run-time interoperability. It is usually a personalised device for a specified owner. The Locus of control and user interface resides in the smart device. The Main characteristics of smart devices: mobility, open service discovery, intermittent resource access.

Smart Pads are hand-held decimetre-sized devices for personalised communication

Smart Skins are fabrics based upon light emitting, conductive, polymers, organic computer devices, can be formed into more flexible non-planar display surfaces and products such as clothes and curtains.

Smart Tabs are Wearable centimetre sized devices to track goods

SOA is a paradigm for organizing and utilizing distributed capabilities that may be under the control of different ownership domains (OASIS)

SOA is defined as a style of IT architecture that delivers enterprise agility and Boundaryless Information Flow (Open Group SOA Working Group)

Stateful senders and receivers can be used to support volatile service invocation design, retaining some intermediate states about messages sent or to buffer sent messages. A stateful exchange may be more complex to synchronise than stateless communication because the equivalence of intermediate states may need to be compared.

Static device is an antonym for mobile: moved before installation, static during versus between sessions.

Superpeer or supernode, see partial P2P.

Synchronous I/O requires the receiver (e.g., server) to be ready to receive before a sender sends, else the sender will have to wait, i.e., the I/O will be blocked

System Virtual Machine or system VM enables multiple OS systems and application to be run on the same hardware. If one system VM fails, other system VMs are isolated and keep their processes running. This is used in in modern servers and server farms that need to support multiple users and their applications, and share hardware resources amongst them.

Tangible, natural Interaction is via natural user interfaces and physical artefact interaction that can involve gestures, touch, voice control, eye gaze control, etc. (Section 5.3)

Task-sharing, Communal, shared meaning systems are where the system interaction is sharable, commonly understood within a limited or well-defined domain (Section 8.4)

Thin-client (server model): Resource poor clients rely on external remote servers and a network that supports remote service access on demand, e.g., mobile terminal with a mini Web browser.

Tight-coupling of a system component means that the component is embedded or integrated with generally a few application domain specific components. This promotes vertical system integration of system components within a single application domain.

Transparency of a system (hide or mask) system properties or functions of a system or components not needed to be known by external entities such as applications and that can be performed automatically. Example types of transparency for distributed services include Access transparency, Concurrency transparency, Failure transparency (Fault Tolerance). In practice, ideal transparency of a single image for all resources and applications to simplify use, all the time and under all conditions, is hard to achieve

Transparent, virtual system reduces the operational complexity of computing, acting as a single virtual system even although it is physically distributed (Section 3.4.1)

UbiCom (Ubiquitous Computing () is a vision for computing to Enable computer-based services to be made available everywhere (Ubiquitous); Support intuitive human usage; But yet, appear to be invisible to the user. A Term Ubiquitous Computing first used in 1991 by Mark Weiser.

UbiCom Related terms: Pervasive computing, Ambient intelligence, Internet of Things, Physical Computing

UbiCom System is a system that contains system components that support a (sub-)set of UbiCom system properties. An UbiCom System operates in an external ICT Environment or infrastructure, e.g., the Internet. It uses services not owned or controlled by itself) from the external ICT Environment or infrastructure.

UbiCom: Different Combinations of Core Properties, No single, absolute definition for ubiquitous computing: distributed, iHCI, context aware, autonomous, intelligent (Poslad, 2009); distributed, iHCI, physical environment context aware (Weiser (1991); ubiquity and transparency (Buxton, 1995); distributed mobile, intelligence, augmented reality (Endres et al. , 2005); autonomy, IHCI (Millner, 2006),

Untethered or unanchored devices have no single natural or artificial host, move using environment forces, i.e., fluid or gas flows

Untethered, amorphous Able to operate independently and proactively, free from external authority, external dependencies are minimized (Sections 2.2.3.2, 6.4.4)

User aware is a system that is aware of its human user(s). Synonyms are Person-aware, User-aware, Personalised, Tailored,

User-aware ICT is aware of presence of user, user ID, user characteristics, current user tasks in relation to goals of users(as part of iHCI and context-awareness)

Utility-based, game-theoretic systems are designed to handle multiple concurrent goals (Section 8.3.5)

Viewpoints of systems can be regarded as architectural patterns - conceptual models that capture the essential elements of an ICT system architecture and its interrelationships, e.g., Individual user view, enterprise user view, Information system, service or computation platform view, Network view. Viewpoint model standards include RM-ODP (ISO), IEEE 1471 model, etc.

Virtual Machines (VM) is an important use of virtualisation for the design of a computer system. There are two types, Process VM and (operating) System VM

Virtualisation of a system or virtual system is an alternative way of reducing system complexity, compared to abstraction, to solve some limitations of abstraction, e.g., with abstraction, components are designed to support one interface need to be redesigned to support another related one, leading to a lack of interoperability. Virtualisation supports the ability to map components in 1 interface at a given level of abstraction into different interfaces and different resources at different levels of abstraction.

Volatile Service Invocation: Sometimes service access may be quite intermittent because of an intermittent network, intermittent service access

Wearable devices are ICT devices usually operated hands-free, e.g., jewellery, watches, earpieces

Web Services (WS) support machine-to-machine interaction via service Interfaces that are machine-processable and syntactical. WS SOAs consist of a range of WS specifications or protocols, depending on the application and service requirements. Core WS SOA protocols are SOAP, WSDL and UDDI.

Zero Configuration Networking (Zeroconf) automatically creates a usable IP network without configuration or special servers (unlike DHCP). It allows inexpert users to connect computers, networked printers, etc., together and expect them to work automatically. Zeroconf currently solves automating three tasks: choosing network addresses, giving a self-address, discovering names and discovering service addresses.