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OPC Unified Architecture
OPC Unified Architecture (OPC UA) is a cross-platform, open-source, IEC62541 standard for data exchange from sensors to cloud applications developed by the OPC Foundation. Distinguishing characteristics are: * Standardized data models freely available for over 60 types of industrial equipment, published by the OPC Foundation via Companion Specifications * Extensible security profiles, including authentication, authorization, encryption and checksums * Extensible security key management, including X.509, token and password * Support for both client-server and publish-subscribe communication patterns * Communication protocol independent. Mappings to several communication protocols like TCP/IP, UDP/IP, WebSockets, AMQP and MQTT are specified * Initially successful in standardized data exchange with industrial equipment (discrete manufacturing, process manufacturing, energy) and systems for data collection and control, but now also leveraged in building automation, weighing and kitc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OPC Foundation
The OPC Foundation (Open Platform Communications, formerly Object Linking and Embedding for Process Control) is an industry consortium that creates and maintains standards for open connectivity of industrial automation devices and systems, such as industrial control systems and process control generally. The OPC standards specify the communication of industrial process data, alarms and events, historical data and batch process data between sensors, instruments, controllers, software systems, and notification devices. The OPC Foundation started in 1994, as a task force comprising five industrial automation vendors ( Fisher-Rosemount, Rockwell Software, Opto 22, Intellution, and Intuitive Technology), with the purpose of creating a basic OLE for Process Control specification. OLE is a technology developed by Microsoft Corporation for the MS Windows operating system. The task force released the OPC standard in August 1996. The OPC Foundation was chartered to continue developme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metadata
Metadata is "data that provides information about other data", but not the content of the data, such as the text of a message or the image itself. There are many distinct types of metadata, including: * Descriptive metadata – the descriptive information about a resource. It is used for discovery and identification. It includes elements such as title, abstract, author, and keywords. * Structural metadata – metadata about containers of data and indicates how compound objects are put together, for example, how pages are ordered to form chapters. It describes the types, versions, relationships, and other characteristics of digital materials. * Administrative metadata – the information to help manage a resource, like resource type, permissions, and when and how it was created. * Reference metadata – the information about the contents and quality of statistical data. * Statistical metadata – also called process data, may describe processes that collect, process, or produce st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OPC Data Access
The OPC Data Access Specification is the first of a group of specifications known as the OPC Classic Specifications. OPC Data Access is a group of client–server standards that provides specifications for communicating real-time data from data acquisition devices such as PLCs to display and interface devices like Human–Machine Interfaces (HMI), SCADA systems and also ERP/ MES systems. The specifications focus on the continuous communication of data. The OPC Data Access specification is also known as OPC DA. OPC DA deals only with real-time data and not historical data (for historical data you need to use OPC Historical Data Access, or OPC HDA) or events (for Alarms and Events you need to use OPC Alarms and Events, or OPC AE). There are three attributes associated with OPC DA data. These are # a value, # the quality of the value, and # a timestamp. The OPC DA specification states that these three attributes have to be returned to an OPC client making a request. Therefore ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WS-Security
Web Services Security (WS-Security, WSS) is an extension to SOAP to apply security to Web services. It is a member of the Web service specifications and was published by OASIS. The protocol specifies how integrity and confidentiality can be enforced on messages and allows the communication of various security token formats, such as Security Assertion Markup Language (SAML), Kerberos, and X.509. Its main focus is the use of XML Signature and XML Encryption to provide end-to-end security. Features WS-Security describes three main mechanisms: * How to sign SOAP messages to assure integrity. Signed messages also provide non-repudiation. * How to encrypt SOAP messages to assure confidentiality. * How to attach security tokens to ascertain the sender's identity. The specification allows a variety of signature formats, encryption algorithms and multiple trust domains, and is open to various security token models, such as: * X.509 certificates, * Kerberos tickets, * User ID/Password cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java Native Interface
In software design, the Java Native Interface (JNI) is a foreign function interface programming framework that enables Java code running in a Java virtual machine (JVM) to call and be called by native applications (programs specific to a hardware and operating system platform) and libraries written in other languages such as C, C++ and assembly. Objectives JNI enables programmers to write native methods to handle situations when an application cannot be written entirely in the Java programming language, e.g. when the standard Java class library does not support the platform-specific features or program library. It is also used to modify an existing application (written in another programming language) to be accessible to Java applications. Many of the standard library classes depend on JNI to provide functionality to the developer and the user, e.g. file I/O and sound capabilities. Including performance- and platform-sensitive API implementations in the standard library allow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Universally Unique Identifier
A universally unique identifier (UUID) is a 128-bit nominal number, label used for information in computer systems. The term globally unique identifier (GUID) is also used. When generated according to the standard methods, UUIDs are, for practical purposes, unique. Their uniqueness does not depend on a central registration authority or coordination between the parties generating them, unlike most other numbering schemes. While the probability that a UUID will be duplicated is not zero, it is generally considered close enough to zero to be negligible. Thus, anyone can create a UUID and use it to identify something with near certainty that the identifier does not duplicate one that has already been, or will be, created to identify something else. Information labeled with UUIDs by independent parties can therefore be later combined into a single database or transmitted on the same channel, with a negligible probability of duplication. Adoption of UUIDs is widespread, with many comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C Data Types
In the C programming language, data types constitute the semantics and characteristics of storage of data elements. They are expressed in the language syntax in form of declarations for memory locations or variables. Data types also determine the types of operations or methods of processing of data elements. The C language provides basic arithmetic types, such as integer and real number types, and syntax to build array and compound types. ''Headers'' for the C standard library, to be used via include directives, contain definitions of support types, that have additional properties, such as providing storage with an exact size, independent of the language implementation on specific hardware platforms. Basic types Main types The C language provides the four basic arithmetic type specifiers ''char'', ''int'', ''float'' and ''double'', and the modifiers ''signed'', ''unsigned'', ''short'', and ''long''. The following table lists the permissible combinations in specifying a larg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Directory
Active Directory (AD) is a directory service developed by Microsoft for Windows domain networks. It is included in most Windows Server operating systems as a set of processes and services. Initially, Active Directory was used only for centralized domain management. However, Active Directory eventually became an umbrella title for a broad range of directory-based identity-related services. A server running the Active Directory Domain Service (AD DS) role is called a domain controller. It authenticates and authorizes all users and computers in a Windows domain type network, assigning and enforcing security policies for all computers, and installing or updating software. For example, when a user logs into a computer that is part of a Windows domain, Active Directory checks the submitted username and password and determines whether the user is a system administrator or normal user. Also, it allows management and storage of information, provides authentication and authorization mec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Public Key Infrastructure
A public key infrastructure (PKI) is a set of roles, policies, hardware, software and procedures needed to create, manage, distribute, use, store and revoke digital certificates and manage public-key encryption. The purpose of a PKI is to facilitate the secure electronic transfer of information for a range of network activities such as e-commerce, internet banking and confidential email. It is required for activities where simple passwords are an inadequate authentication method and more rigorous proof is required to confirm the identity of the parties involved in the communication and to validate the information being transferred. In cryptography, a PKI is an arrangement that ''binds'' public keys with respective identities of entities (like people and organizations). The binding is established through a process of registration and issuance of certificates at and by a certificate authority (CA). Depending on the assurance level of the binding, this may be carried out by an automa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SOAP
Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are used as thickeners, components of some lubricants, and precursors to catalysts. When used for cleaning, soap solubilizes particles and grime, which can then be separated from the article being cleaned. In hand washing, as a surfactant, when lathered with a little water, soap kills microorganisms by disorganizing their membrane lipid bilayer and denaturing their proteins. It also emulsifies oils, enabling them to be carried away by running water. Soap is created by mixing fats and oils with a base. A similar process is used for making detergent which is also created by combining chemical compounds in a mixer. Humans have used soap for millennia. Evidence exists for the production of soap-like materials in ancient Babylon around 2800 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WS-SecureConversation
WS-SecureConversation is a Web Services specification, created by IBM and others, that works in conjunction with WS-Security, WS-Trust and WS-Policy to allow the creation and sharing of security contexts. Extending the use cases of WS-Security, the purpose of WS-SecureConversation is to establish security contexts for multiple SOAP message exchanges, reducing the overhead of key establishment. Features * Establish a new security context in following modes: ** Security context token created by a security token service (WS-Trust STS) ** Security context token created by one of the communicating parties and propagated with a message ** Security context token created through negotiation/exchanges * Renew security context * Amend Security context (add claims) * Cancel security context * Derive key: parties may use different keys per side and function (sign/encrypt), and change keys frequently to prevent cryptographic attacks * Maintain high secure context WS-SecureConversation is m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linux
Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which includes the kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name "GNU/Linux" to emphasize the importance of GNU software, causing some controversy. Popular Linux distributions include Debian, Fedora Linux, and Ubuntu, the latter of which itself consists of many different distributions and modifications, including Lubuntu and Xubuntu. Commercial distributions include Red Hat Enterprise Linux and SUSE Linux Enterprise. Desktop Linux distributions include a windowing system such as X11 or Wayland, and a desktop environment such as GNOME or KDE Plasma. Distributions intended for ser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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