Bang-bang control

by ronfluegge 5. January 2018 16:22

Bang-bang control is a type of control system that mechanically or electronically turns something on or off when a desired target (setpoint) has been reached. Bang-bang controllers, which are also known as two-step controllers, on-off controllers or hysteresis controllers, are used in many types of home and industrial control systems (ICS).

An old-fashioned house thermostat, for example, uses bang-bang control. When the temperature drops to a pre-determined low set point, the thermostat switches the heating system on. When the temperature reaches a pre-determined high set point, the thermostat switches the heating system off. Depending upon the set points, this can result in a fairly wide range of acceptable temperatures and cause the heating system to have a fairly long response time. This is why bang-bang controllers are sometimes referred to as hysteresis controllers -- the word hysteresis describes a lag in response to change.

In product development, bang-bang control systems can be contrasted with proportional control systems. A smart thermostat in a hotel room, for example, might determine when there is an error between the setpoint and the current value of the process variable (the room's temperature) and respond to the slight deviation by opening or closing dampers. Proportional controls are more exact and have faster response times than bang-bang, all or nothing controls.

Light switches and dimmer switches also illustrate the difference between bang-bang and proportional controls. A light switch, which can be either on or off, uses bang-bang control. A dimmer switch, in contrast, reduces or increases power to the lighting load in order to achieve a lower or higher light output and uses proportional control.

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GADS OS Application Statistics 2011 - 2017

by ronfluegge 28. December 2017 16:48

The GADS Open Source website statistics for the first 7 years:

Installation Downloads - 13,335

Downloaded Files Bandwidth - 151,619.9 MB

Page views - 279,308

     United States - 225,646

     Canada - 2,524

     Argentina - 76

     Brazil - 325

     Mexico - 62

     Ireland - 42

     Australia - 225

     New Zealand - 21

Unique IP visitor addresses - 56,403

Bandwidth - Bandwidth represents the total number of kilobytes that were sent to people visiting our site.

Page Views - A page view is a successful request for a file on our web site that is considered to be a page.

LDAP Injection

by ronfluegge 15. December 2017 16:05

LDAP injection is a type of security exploit that is used to compromise the authentication process used by some websites. Websites that construct Lightweight Directory Access Protocol (LDAP) statements from data provided by users are vulnerable to this type of attack.

LDAP directories store information, known as objects, for people, servers, printers and roles. If the directory is used for website authentication, the attacker can enter malicious code into a user input field, gain unauthorized access to the directory and view or change usernames and passwords.

LDAP injection works in much the same manner as SQL injection, a type of security exploit in which the attacker adds SQL (Structured Query Language) code to a Web form. Both types of attacks primarily occur due to missing or weak input validation that does not reject malformed input or strip malicious LDAP control characters before including untrusted user input in a query.

According to security experts, the main reason that LDAP injection and similar exploits work is the fact that security is not sufficiently emphasized during the application development process. To protect the integrity of Web sites that use forms, experts recommend implementing a sanitization process to control the types and numbers of characters that can be accepted by input boxes as well as the use of multi-factor authentication (MFA) for public-facing web applications.

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