String (computer science)

About: String (computer science) is a research topic. Over the lifetime, 19430 publications have been published within this topic receiving 333247 citations. The topic is also known as: str & s.

Static checking of dynamically generated queries in database applications

Abstract: Many data-intensive applications dynamically construct queries in response to client requests and execute them. Java servlets, e.g., can create string representations of SQL queries and then send the queries, using JDBC, to a database server for execution. The servlet programmer enjoys static checking via Java's strong type system. However, the Java type system does little to check for possible errors in the dynamically generated SQL query strings. Thus, a type error in a generated selection query (e.g., comparing a string attribute with an integer) can result in an SQL runtime exception. Currently, such defects must be rooted out through careful testing, or (worse) might be found by customers at runtime. In this paper, we present a sound, static, program analysis technique to verify the correctness of dynamically generated query strings. We describe our analysis technique and provide soundness results for our static analysis algorithm. We also describe the details of a prototype tool based on the algorithm and present several illustrative defects found in senior software-engineering student-team projects, online tutorial examples, and a real-world purchase order system written by one of the authors.

Constructing deterministic finite-state automata in recurrent neural networks

Abstract: Recurrent neural networks that are trained to behave like deterministic finite-state automata (DFAs) can show deteriorating performance when tested on long strings. This deteriorating performance can be attributed to the instability of the internal representation of the learned DFA states. The use of a sigmoidel discriminant function together with the recurrent structure contribute to this instability. We prove that a simple algorithm can construct second-order recurrent neural networks with a sparse interconnection topology and sigmoidal discriminant function such that the internal DFA state representations are stable, that is, the constructed network correctly classifies strings of arbitrary length. The algorithm is based on encoding strengths of weights directly into the neural network. We derive a relationship between the weight strength and the number of DFA states for robust string classification. For a DFA with n state and minput alphabet symbols, the constructive algorithm generates a “programmed” neural network with O(n) neurons and O(mn) weights. We compare our algorithm to other methods proposed in the literature.

Fast data compressor with direct lookup table indexing into history buffer

Abstract: A cooperating data compressor, compressed data format, and data decompressor The compressor compresses an input data block (HB) to a compressed data block having the format The decompressor decompresses the compressed data block to restore the original data block The compressor has a direct lookup table (DLT) of 28×N entries, each indexable by N bytes at a current HB location and identifying a target HB location The compressor determines whether a target string at the target HB location matches a current string at the current HB location If they do not match, the compressor outputs a literal representing a datum at the current location If they match, the compressor outputs a vector from the current location to the target string Compression speed is maximized by the direct addressing of the DLT by the current N bytes in the HB Decompression speed is maximized by state machine operation according to literal/vector indicators, special case string length codes, and special case offset codes in the compressed data format

Physical Modeling of Plucked String Instruments with Application to Real-Time Sound Synthesis

Abstract: An efficient approach for real-time synthesis of plucked string instruments using physical modeling and DSP techniques is presented Results of model-based resynthesis are illustrated to demonstrate that high-quality synthetic sounds of several string instruments can be generated using the proposed modeling principles Real-time implementation using a signal processor is described, and several aspects of controlling physical models of plucked string instruments are studied

Method for determining boundaries of words in text

Abstract: A method for determining the boundaries of a symbol or word string within an image, including the steps of determining page orientation, isolating symbol strings from adjacent symbol strings, establishing a set of boundaries or references with respect to which measurements about, or further processing of, the symbol string may be made.