Performance Evaluation of Efficient Routing Protocols in Delay Tolerant Network under Different Human Mobility Models

Namita Mehta,Mehul Shah 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.1

Delay and/or Disruption-Tolerant Networking (DTN) is a novel communication prototype that can span across multiple networks and deal with unpredicted conditions in the Internet model.Delay-tolerant networks (DTNs) are partitioned wireless ad hoc networks with intermittent connectivity. Additional terminology in this family of dynamic networks includes disruption-tolerant networks, intermittently connected networks, and opportunistic networks. Routing of the packets in DTN is based on store-carry-and forward paradigm. In this paper, we study and analyze performance of well known PROPHET and Spray and Wait routing protocol, under different human mobility models such as Truncated Levy Walk mobility model (TLW),Self-similar Least Action Walk (SLAW) and Random way point (RWP) model. The MATLAB simulator is used in order to analyze the performance of these routing protocols.Simulation results illustrate that Spray and Wait significantly outperforms the PROPHET on aspects of delivery ratio, average delay and communication overhead.

Human-Mobility-Based Spray and Wait: Efficient Routing Protocol for Pocket Switched Networks

Namita Mehta,Mehul Shah 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.1

Delay and/or Disruption-Tolerant Networking (DTN) is a novel communication prototype that can span across multiple networks and deal with unpredicted conditions in the Internet model. Pocket Switched Networks (PSN) are delay tolerant networks with hand held devices. Nodes in a PSN make use of a store-carry-and-forward paradigm to communicate along with themselves. The routing protocols performances that have been developed for DTN based on the movement pattern of the nodes. We propose a Human Mobility based Spray & Wait Routing protocol (HMSaW). This protocol makes use of truncated power law distribution of pause time and flight length of human mobility to smartly forward data in DTN and PSN. Simulation results show that the proposed HMSaW shows better delivery ratio and the communication overhead, with marginal reduction in average delay compared to existing PROPHET and Spray & Wait Routing protocol.

Performance of Efficient Routing Protocol in Delay Tolerant Network : A Comparative Survey

Namita Mehta,Mehul Shah 보안공학연구지원센터 2014 International Journal of Future Generation Communi Vol.7 No.1

Trends of inflammatory bowel disease at a tertiary care center in northern India

( Ajit Sood ),( Kirandeep Kaur ),( Arshdeep Singh ),( Vandana Midha ),( Ramit Mahajan ),( Namita Bansal ),( Varun Mehta ),( Dharmatma Singh ) 대한장연구학회 2021 Intestinal Research Vol.19 No.3

Background/Aims: Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD), is increasingly being reported from India and other Asian countries. This study looks into the changing trends of IBD at a tertiary care center in north India over last two decades. Methods: Retrospective analysis of a prospectively maintained database of patients diagnosed with IBD between January 1991 and December 2015 was conducted. The study period was divided into five times cohorts (1991-1995, 1996-2000, 2001-2005, 2006-2010, 2011-2015). Results: During the study period, 2,467 patients (UC [n=2,137, 86.6%], CD [n=330, 13.3%], mean age 38.5±13.3 years; 55.9% males) were registered. The proportion of patients with CD increased (ratio of UC to CD declined from 15.7:1 to 4:1). The mean age at diagnosis decreased for UC (45.7±12.1 years in 1991-1995 vs. 37.6±13.0 years in 2011-2015; P=0.001) and remained consistent for CD (41.3±13.6 years in 1996-2000 vs. 41.3±16.9 years in 2011-2015, P=0.86). Patients with proctitis in UC and isolated ileal disease in CD increased over the study period (P=0.001 and P=0.007, respectively). Inflammatory CD increased (P=0.009) whereas stricturing CD decreased (P=0.01) across all cohorts. There was a trend towards less severe presentation of both UC and CD. The use of thiopurines (P=0.02) and biologics increased (P=0.001) with no significant change in trends for requirements of surgery (P=0.9). Conclusions: Increasing prevalence of CD, younger age at diagnosis, diagnosis at an earlier and milder stage, greater use of thiopurines and biologics were observed. (Intest Res 2021;19:282-290)

Clinical spectrum of elderly-onset inflammatory bowel disease in India

Yogesh Kumar Gupta,Arshdeep Singh,Vikram Narang,Vandana Midha,Ramit Mahajan,Varun Mehta,Dharmatma Singh,Namita Bansal,Madeline Vithya Barnaba Durairaj,Amit Kumar Dutta,Ajit Sood 대한장연구학회 2023 Intestinal Research Vol.21 No.2

Background/Aims: Inflammatory bowel disease (IBD) is increasingly being recognized in elderly patients. Data on clinical spectrum of elderly-onset IBD patients is lacking from India. Methods: A cross-sectional retrospective analysis of a prospectively maintained database of patients diagnosed with IBD was conducted at 2 centers in India. The clinical spectrum of elderly-onset IBD including demographic profile (age and sex), clinical presentation, disease characteristics (disease behavior and severity, extent of disease), and treatment were recorded and compared with adult-onset IBD. Results: During the study period, 3,922 (3,172 ulcerative colitis [UC] and 750 Crohn’s disease [CD]) patients with IBD were recorded in the database. A total of 186 patients (4.74%; 116 males [62.36%]) had elderly-onset IBD (69.35% UC and 30.64% CD). Diarrhea, blood in stools, nocturnal frequency and pain abdomen were the commonest presentations for UC, whereas pain abdomen, weight loss and diarrhea were the most frequent symptoms in CD. For both elderly onset UC and CD, majority of the patients had moderately severe disease. Left-sided colitis was the commonest disease location in UC. Isolated ileal disease and inflammatory behavior were the most common disease location and behavior, respectively in CD. 5-Aminosalicylates were the commonest prescribed drug for both elderly onset UC and CD. Thiopurines and biologics were used infrequently. Prevalence of colorectal cancer was higher in elderly onset IBD. Conclusions: Elderly onset IBD is not uncommon in India. Both the elderly onset UC and CD were milder, with no significant differences in disease characteristics (disease extent, location and behavior) when compared to adult-onset IBD. Colorectal cancer was more common in elderly onset IBD.

Maintaining infliximab induced clinical remission with azathioprine and 5-aminosalicylates in acute severe steroid-refractory ulcerative colitis has lower cost and high efficacy (MIRACLE): a multicenter study

( Ramit Mahajan ),( Arshdeep Singh ),( Saurabh Kedia ),( Kirandeep Kaur ),( Vandana Midha ),( Pabitra Sahu ),( Varun Mehta ),( Dharmatma Singh ),( Namita Bansal ),( Khushdeep Dharni ),( Sandeep Kausha 대한장연구학회 2022 Intestinal Research Vol.20 No.1

Background/Aims: Infliximab (IFX) has been used to induce and maintain remission in patients with severe steroid-refractory ulcerative colitis (UC). Long-term use of biologics in developing countries is limited by high cost and frequent side effects. An optimal maintenance strategy in these patients needs to be established. Methods: A retrospective analysis of maintenance of clinical remission with combination of azathioprine (AZA) and 5-aminosalicylates (5-ASA) in patients with severe steroid-refractory UC where IFX (5 mg/kg intravenously at weeks 0, 2, 6) had been used only as an induction therapy was done at 2 centers in India. Primary outcome was the proportion of patients maintaining corticosteroid-free sustained clinical remission (SCR) at the end of study period. Rates of relapse and cost of therapy were also analyzed. Results: Of the 137 patients who received rescue IFX induction therapy, 77 (56.2%) achieved clinical remission (mean age 34.81±13.32 years, 68.83% males, median follow-up 4 years, range 3 months to 6 years) and were included. Cumulative corticosteroid-free SCR was maintained in 68%, 59%, 42%, and 35% patients at 1, 2, 4, and 6 years respectively. Sixty-seven relapses were observed in 33 patients. Majority of the relapses (45/67, 67.16%) occurred within first 2 years of follow-up. Two relapses were managed with re-induction with IFX, one required colectomy, whereas all other responded to repeat course(s) of corticosteroids. Annual per capita maintenance therapy with 5-ASA and AZA was cheaper by US$ 4,526 compared to maintaining remission with IFX. Conclusions: Clinical remission achieved with IFX induction therapy in severe steroid-refractory UC can be sustained over long time with a combination of AZA and 5-ASA. (Intest Res 2022;20:64-71)

Inflammatory bowel disease (IBD)-disk accurately predicts the daily life burden and parallels disease activity in patients with IBD

( Arshdeep Singh ),( Yogesh Kumar Gupta ),( Ashvin Singh Dhaliwal ),( Bhavjeet Kaur Kahlon ),( Vasu Bansal ),( Ramit Mahajan ),( Varun Mehta ),( Dharmatma Singh ),( Ramandeep Kaur ),( Namita Bansal ) 대한장연구학회 2023 Intestinal Research Vol.21 No.3

Background/Aims: The inflammatory bowel disease (IBD)-disk is a validated, visual, 10-item, self-administered questionnaire used to evaluate IBD-related disability. The present study aimed to evaluate IBD-disk in assessment of IBD daily life burden and its relation with disease activity. Methods: A cross-sectional study was conducted between June 2021 and December 2021. Patients with IBD were asked to complete the IBD-disk and a visual analogue scale of IBD daily-life burden (scored from 0-10, score >5 indicative of high burden). The internal consistency of IBD-disk, correlation with IBD daily life burden and disease activity (assessed by partial Mayo score and Harvey Bradshaw Index in patients with ulcerative colitis [UC] and Crohn’s disease [CD], respectively) and diagnostic performance of IBD-disk to detect high burden were analyzed. Results: Out of the 546 patients (mean age 40.33±13.74 years, 282 [51.6%] males) who completed the IBD-disk, 464 (84.98%) had UC and the remaining (n=82, 15.02%) had CD. A total of 311 patients (291 UC and 20 CD; 56.95%) had active disease. The mean IBD-disk total score and IBD daily life burden were 18.39±15.23 and 2.45±2.02, respectively. The IBD-disk total score correlated strongly with the IBD daily life burden (ρ=0.94, P< 0.001), moderately with partial Mayo score (ρ=0.50) and weakly with Harvey Bradshaw Index (ρ=0.34). The IBD-disk total score >30 predicted high IBD daily-life burden. Conclusions: The IBD-disk accurately predicts the daily life burden and parallels disease activity in patients with IBD and can be applied in clinical practice. (Intest Res 2023;21:375-384)