Showing papers by "Telkom Institute of Technology published in 2009"
TL;DR: In this article, a mathematical model for gas lift well system, where the ∞uid ∞ow in reservoir and pipes consists of liquid and gas, was developed, and a computation scheme was developed based on genetic algorithms.
Abstract: 1. Abstract Optimization problem for oil production in a multi gas lift wells system is discussed. The main problem is to identify allocation of gas injection for each well to obtain maximum total oil production. The gas injection rate is constrained by a maximum limit. Oil production rate is a nonlinear function of gas injection rate, which is unknown explicitly. In existing approaches, the nonlinear function is estimated from empirical or numerical simulation data, by curve fltting using regression method, or estimated by piecewise linear function. We developed here, a mathematical model for gas lift well system, where the ∞uid ∞ow in reservoir and pipes consists of liquid and gas, so the conditions represent two phase ∞ow phenomena. Relationship between gas injection and oil production is given implicitly from the model. We have also developed a computation scheme to solve the optimization problem. Considering complexity of the problem, computation scheme is developed based on genetic algorithms. Our results show quite good estimation for optimum solution. The approach also gives better quality prediction over existing approach, since all computation results come from the model, not from regression or interpolation. 2. Keywords: Gas Lift, Gas Lift Performance Curve, Constrained Optimization, Genetic Algorithm.
25 citations
01 Nov 2009
TL;DR: In this paper, a method of detecting unwanted motion blur effects that appear local within an arbitrary area on a digital image is presented. And the outcome of this detection are then subsequently used to improve the quality of the image by means of pixel correlation based deblurring method applied to the specific area identified by the motion blur detector.
Abstract: One of the frequently encountered problems in photography is the appearance of motion blurring effect due to either object movement or camera motion associated with the speed of the camera (shutter speed) when pictures are taken. This Paper presents a novel but simple method of detecting unwanted motion blur effects that appear local within an arbitrary area on a digital image. The proposed method uses various size block-based discrete cosine transform (DCT) calculations on the distorted image. The outcome of this detection are then subsequently used to improve the quality of the image by means of pixel correlation based deblurring method applied to the specific area identified by our motion blur detector. Subjective experiment to evaluate the quality of the resulting enhanced image is then conducted and objective evaluations using several published image quality metrics are also computed. Experimental results show that the quality of the enhanced images produced by the chosen deblurring method is better when local motion blur detection is employed than those without blur detection. Out of various block sizes used in the experiment, block size of 32}32 pixels produce better perceived quality.
20 citations
Proceedings Article•
01 Jan 2009TL;DR: A simple modification to the EVRC rate determination algorithm (EVRC RDA) is developed to exploit the noise-canceling property of differential microphone array to improve its performance in highly dynamic noise environment.
Abstract: Differential microphone array is known to have low sensitivity to distant sound sources. Such characteristics may be advantageous in voice activity detection where it can be assumed that the target speaker is close and background noise sources are distant. In this paper we develop a simple modification to the EVRC rate determination algorithm (EVRC RDA) to exploit the noise-canceling property of differential microphone array to improve its performance in highly dynamic noise environment. Comprehensive computer simulations show that the modified algorithm outperforms the original EVRC RDA in all tested noise conditions.
6 citations
28 Apr 2009
TL;DR: This research implements and investigates the H.264 and MPEG-4 video codec, as well as the quality of their transport over wireless environment, particularly Mobile IPv4 and Adhoc networks, and presents that the video quality is sufficiently prominent when the client/mobile node is locating either at Home Network or Foreign Network.
Abstract: As the rapid growth of multimedia communication demand, it is inevitable to develop a method that could convey multimedia applications on IP network that is previously a text-based communication. In this research, we implement and investigate the H.264 and MPEG-4 video codec, as well as the quality of their transport over wireless environment, particularly Mobile IPv4 and Adhoc networks. Video quality measurement is conducted by means of PSNR and MOS parameters, while network QoS parameters embrace one way delay, inter arrival jitter, packet loss, and user throughput. The outcomes of this research present that the video quality is sufficiently prominent when the client/mobile node is locating either at Home Network or Foreign Network.
1 citations