http://localhost:80/xmlui/handle/123456789/17403 Fri, 03 Apr 2026 23:09:34 GMT 2026-04-03T23:09:34Z http://localhost:80/xmlui/handle/123456789/19114 Title: NETWORK LATENCY EFFECT ON USER PERFORMANCE IN COLLABORATIVE VIRTUAL ENVIRONMENT USING TASK DISTRIBUTION MODEL Authors: S. Khalid; S. Ullah; A. Alam; N. Ali Abstract: Collaborative Virtual Environments (CVEs) are used for training, education, teleconferencing and assembly of synthetic objects. Network latency, loose coordination, no task distribution strategy and less awareness are the main factors that affect user performance in CVEs. The effect of network latency on user performance in CVE was analyzed. Visual and audio feedback was used for communication between the collaborators. Based on task distribution model, a simulated environment for collaborative assembly task was developed to conduct the experiments. The experiments were performed on different college students comprising of 20 virtual teams of 40 individuals using the latency from 0 to 5000 msec in LAN. The result showed that the user‟s performance was better in dynamic with audio with no latency, but whenever the lag was increased the task completion time increased than dynamic with textual based. At 1000 msec latency, the dynamic with audio and textual modality values were almost the same. Above 1000 msec of latency, the user performance in dynamic with textual was better as compared to dynamic with audio. Tue, 20 Jun 2017 00:00:00 GMT http://localhost:80/xmlui/handle/123456789/19114 2017-06-20T00:00:00Z http://localhost:80/xmlui/handle/123456789/19113 Title: AN EFFICIENT ALGORITHMIC SOLUTION FOR HIGH PAYLOAD GOOD IMPERCEPTIBILITY HYBRID IMAGE STEGANOGRAPHY Authors: A. Murtaza; F. Shaukat; G. Raja; A.K. Khan Abstract: A hybrid steganographic technique has been proposed to enlarge the size of secret message and to hide several images in one cover image. Initially, the secret images were compressed using JPEG 2000 before embedding them to the cover image. Second least significant bit plane of cover image was entirely replaced by secret message while tri-ways-pixel-value-differencing (TPVD) was used to hide secret message in remaining seven-bit cover image. The quality of stego image was enhanced by residual image coding (RIC). The cover image was divided in four sub-images, three of them provided cover for secret message using proposed technique while fourth sub-image was used to embed RIC of stego image using only TPVD, to ensure better quality in terms of peak signal to noise ratio (PSNR). Proposed technique provided the opportunity to transmit secret data without detection by different steganalysis techniques like dual statistics steganalysis. Experimental results verified that proposed technique achieved high payload with better image quality than TPVD scheme. Tue, 20 Jun 2017 00:00:00 GMT http://localhost:80/xmlui/handle/123456789/19113 2017-06-20T00:00:00Z http://localhost:80/xmlui/handle/123456789/19112 Title: AN ALGORITHM TO SEGMENT THE MID-BRAIN STRUCTURES USING MULTIRESOLUTION NON-RIGID REGISTRATION Authors: I. Amjad; F. Shaukat; G. Raja; A.K. Khan Abstract: In present study, a reference based technique has been proposed to segment midbrain structures in 3D Magnetic Resonance (MR) images using multi-resolution non-rigid registration. The proposed scheme segmented the mid-brain structures in two stages. During first stage, a target image was registered to an already segmented reference image while in second stage, segmentation information was mapped from reference to target medical image. Using this scheme, the aim was to segment nine mid-brain structures including left ventricle, right ventricle, third ventricle, anterior commissure, posterior commissure, left putamen, right putamen, left caudate nucleus and right caudate nucleus. Results of automatic segmentation achieved through reference based non-rigid registration were validated by comparing with the manual segmentation, considered as ground truth. Three metrics namely Dice Coefficient, Sensitivity and Positive Predictive Values were used for assessing the segmentation results. The proposed algorithm showed the satisfactory segmentation of mid-brain structures by achieving a mean sensitivity of 89. 85 % for five target MR images. The results indicated that the proposed scheme performed accurate segmentation of mid-brain structures. Tue, 20 Jun 2017 00:00:00 GMT http://localhost:80/xmlui/handle/123456789/19112 2017-06-20T00:00:00Z http://localhost:80/xmlui/handle/123456789/19111 Title: BIOFILM FORMATION AND CALCIUM PRECIPITATION IN BACILLUS LICHENIFORMIS AND ALCALIGENES FAECALIS FOR SOIL IMPROVEMENT Authors: B. Zeb; B. Zainab; J. Siddique; K. Zahid; N. Khaliq; A.W. Qurashi Abstract: Calcium precipitation and biofilm formation in halophilic bacteria were investigated in the current study. The strain SMK (Bacillus licheniformis) was isolated from plant rhizosphere and and AQ-1 (Alcaligenes faecalis) from marble crushing soil in Lahore. Bacterial growth, biofilm formation and CaCO3 precipitation of both strains was determined under varying stress (pH, temperature, agitation and salinity). Soil aggregation was investigated under salt stress (NaCl and MgSO4). Results showed that pH 8.0, temperature 42°C, 1.5 M salt (NaCl and MgSO4) stress without agitation was favorable for biofilm formation. Both strains were able to precipitate CaCO3 in media specially at margins of colonies in AQ-1. Effervescence of crystals with addition of concentrated HCl showed confirmatory results. Stereomicroscopic analysis of aggregates in inoculated soil and sand showed precipitation under salt stress. SMK (Bacillus licheniformis) showed high aggregation in soil. From the results, it was concluded that these indigenous strains have potential for sustainable agriculture by improving disturbed soil. Tue, 20 Jun 2017 00:00:00 GMT http://localhost:80/xmlui/handle/123456789/19111 2017-06-20T00:00:00Z