State (computer science)

About: State (computer science) is a research topic. Over the lifetime, 24436 publications have been published within this topic receiving 225733 citations.

Logic for improving integrity checking in relational data bases

Abstract: When an "updating" operation occurs on the current state of a data base, one has to ensure the new state obeys the integrity constraints. So, some of them have to be evaluated on this new state. The evaluation of an integrity constraint can be time consuming, but one can improve such an evaluation by taking advantage from the fact that the integrity constraint is satisfied in the current state. Indeed, it is then possible to derive a simplified form of this integrity constraint which is sufficient to evaluate in the new state in order to determine whether the initial constraint is still satisfied in this new state. The purpose of this paper is to present a simplification method yielding such simplified forms for integrity constraints. These simplified forms depend on the nature of the updating operation which is the cause of the state change. The operations of inserting, deleting, updating a tuple in a relation as well as transactions of such operations are considered. The proposed method is based on syntactical criteria and is validated through first order logic. Examples are treated and some aspects of the method application are discussed.

Process control system including automatic sensing and automatic configuration of devices

Abstract: A digital control system with a predetermined configuration automatically senses the connection to a network of a digital device that is not included in the predetermined configuration. The digital device is assigned temporary address information and placed in a temporary state, called a standby state, in which the digital device supplies information to the digital control system allowing a user to access the digital device including access of device information and configuration parameters. Using the device information and configuration parameters, a user selectively commissions the digital device by assigning a physical device tag, a device address, and a device identification, and installing a control strategy to the digital device, thereby placing the digital device in an operational state in communication with the digital control system. In the standby state, a user interrogates to determine the type of device that is attached, determines the role of the device in the context of the digital control system, assigns a physical device tag that assigns the determined role to the device, and verifies connection of the device to the network. Also in the standby state, the user initiates other applications applied to the device, including calibration of the device and configuring the device within the overall control scheme of the digital control system.

A method circuit and system for read error detection in a non-volatile memory array

Abstract: The present invention is a method, circuit and system for determining a reference voltage to be used in reading cells programmed to a given program state. Some embodiments of the present invention relate to a system, method and circuit for establishing a set of operating reference cells to be used in operating (e.g. reading) cells in a NVM block or array. As part of the present invention, at least a subset of cells of the NVM block or array may be read and the number of cells found at a given state associated with the array may be compared to one or more check sum values obtained during programming of the at least a subset of cells. A Read Verify threshold reference voltage associated with the given program state or associated with an adjacent state may be adjusted based on the result of the comparison.

Static state estimation in electric power systems

Abstract: A static state estimator is a collection of digital computer programs which convert telemetered data into a reliable estimate of the transmission network structure and state by accounting for 1) small random metering-communication errors; 2) uncertainties in system parameter values; 3) bad data due to transients and meter-communication failures; and 4) errors in the network structure due to faulty switch-circuit breaker status information. The overall state estimation process consists of four steps: 1) hypothesize mathematical structure; 2) estimate state vector; 3) detect bad data and/or structure errors; and identify bad data and/or structure errors. The problem is characterized by high dimensionality and the need for real-time solutions using limited computer time and storage. Various methods of solution are discussed and compared.

The Complexity of Finite Functions.

Abstract: Publisher Summary This chapter discusses the complexity of finite functions. A deterministic Turing machine consists of a finite control and a finite collection of tapes each with a head for reading and writing. The finite control is a finite collection of states. A tape is an infinite list of cells each containing a symbol. Initially, all tapes have blanks except for the first, which contains the input string. Once started, the machine goes from state to state, reading the symbols under the heads, writing new ones, and moving the heads. The exact action taken is governed by the current state, the symbols read, and the next-move function of the machine. This continues until a designated halt state is entered. The machine indicates its output by the halting condition of the tapes. In a nondeterministic Turing machine, the next-move function is multivalued. There can be several computations on a given input and several output values.