Computer communications

In order to improve Web performance, Web caching is recognized to be one of the effective techniques. This paper gives a brief survey of previous works on schemes to solve the problems of Web caching, and finally describes some desirable characteristics.

Caching on the World Wide Web

A computer-implemented method is disclosed. The method includes collecting cache-efficiency-indicator values of an at least one cache fragment during operation of a database system over a period of time. Providing approximation-function-parameter values for the collected, cache-efficiency-indicator values, an approximation function representing a relation between a cache-efficiency-indicator and the size of a respective cache fragment. The method continues by providing a set of workload windows based on the approximation-function-parameter values. Next, providing a workload-window information for the set of workload windows, the workload-window information including at least one approximation-function-parameter value representing each determined workload window. The method further includes storing the workload-window information for a comparison based on current, cache-efficiency-indicator values and the workload-window information.

Cache Configuration in a Database System

A system and method are disclosed to improve processing time of a database system by continuous automatic background optimization of a cache memory that is fragmented into a plurality of cache fragments is described. The system and method include collecting indicators about efficiency of individual cache fragments by at least one of measuring a cache hit ratio of each cache fragment, measuring a processing time that a CPU of the database system needs to prepare data in the individual cache fragments, and measuring execution time the CPU needs to process the data in accordance with a SQL query. The system and method include calculating and revising approximation curves for measured values of each cache fragment to find a combination of cache fragment sizes with a highest system throughput. The system and method include changing the sizes of the cache fragments to receive highest system throughput.

System and method to improve processing time of databases by cache optimization

The main goal of this study was to compare the performances of genetic algorithm (GA) and ant colony optimization (ACO) algorithm for PID controller tuning on a pressure control process. GA and ACO were used for tuning of the PID controller when predefined trajectory reference signal was applied. Offline learning approach was employed in both GA and ACO algorithms. Realized pressure process dynamic has nonlinear behavior, thus system was modeled by nonlinear auto regressive and exogenous input (NARX) type artificial neural network (ANN) approach. PID controller was also tuned by Ziegler–Nichols (Z–N) method to compare the results. A cost function was design to minimize the error along the defined cubic trajectory for the GA-PID and ACO-PID controller. Then PID controller parameters (Kp, Ki, Kd) were found by GA-PID, ACO-PID algorithms, which were adjusted with their optimal parameters. It was concluded that both ACO and GA algorithms could be used to tune the PID controllers in the pressure process with excellent performance. This material is suitable for an engineering course on neural networks, genetic algorithm, ant colony optimization and process control laboratory. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 20: 518–528, 2012

Trajectory tracking performance comparison between genetic algorithm and ant colony optimization for PID controller tuning on pressure process

A novel dynamic cache size adjustment approach for better data retrieval performance over the internet

E-MACSC: A novel dynamic cache tuning technique to reduce information retrieval roundtrip time over the Internet

The E-MACSC (Enhanced Model for Adaptive Cache Size Control ( ) is a novel approach for dynamic cache l tuning. The aim is to adaptively tune the cache size at runtime to maintain the prescribed hit ratio. It works with the popularity ratio (PR), defined by the standard deviations sampled for the relative popularity profile of the data objects at two successive time points. The changes in the PR value reflect the shifts of users' preference toward certain data objects. The E-MACSC makes use of the Convergence Algorithm (CA), which is an IEPM (Internet End-to-End Performance Measurement ( ) technique that measures the mean of a waveform quickly and accurately. Accuracy of the measurement is independent/insensitive to the waveform pattern because the CA is derived from the Central Limit Theorem.

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E-MACSC: A novel dynamic cache tuning technique to maintain the hit ratio prescribed by the user in internet applications

The self-similarity (S 2) filter is proposed for real-time applications. It can be used independently or as an extra component for the enhanced RTPD (real-time traffic pattern detector) or E-RTPD. The S 2 filter basis is the “asymptotically second-order self-similarity” concept (alternatively called statistical 2 nd OSS or S2 nd OSS) for stationary time series. The focus is the IAT (inter-arrival times) traffic. The filter is original because similar approaches are not found in the literature for detecting self-similar traffic patterns on the fly. Different experiments confirm that with help form the S 2 filter the FLC (Fuzzy Logic Controller) dynamic buffer size tuner control more accurately. As a result the FLC improves the reliability of the client/server interaction path leading to shorter roundtrip time (RTT).

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A Novel Real-Time Self-similar Traffic Detector/Filter to Improve the Reliability of a TCP Based End-to-End Client/Server Interaction Path for Shorter Roundtrip Time

Richard S. L. Wu

Papers

A novel dynamic cache size adjustment approach for better data retrieval performance over the internet

E-MACSC: A novel dynamic cache tuning technique to reduce information retrieval roundtrip time over the Internet

E-MACSC: A novel dynamic cache tuning technique to maintain the hit ratio prescribed by the user in internet applications

A Novel Real-Time Self-similar Traffic Detector/Filter to Improve the Reliability of a TCP Based End-to-End Client/Server Interaction Path for Shorter Roundtrip Time

RDCT: A novel reconfigurable dynamic cache size tuner to shorten information retrieval time over the internet