Long Noncoding RNA Taurine-Upregulated Gene1 (TUG1) Promotes Tumor Growth and Metastasis Through TUG1/Mir-129-5p/Astrocyte-Elevated Gene-1 (AEG-1) Axis in Malignant Melanoma.

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Long, Jianwen; Menggen, Qiqige; Wuren, Qimige; Shi, Quan; Pi, Xianming

2018-03-15

BACKGROUND Malignant melanoma is a class of malignant tumors derived from melanocytes. lncRNAs have been considered as pro-/anti-tumor factors in progression of cancers. The function of lncRNA TUG1 on growth of melanoma was investigated in this study. MATERIAL AND METHODS The TUG1 and miR-129-5p expression were examined via qRT-PCR. The protein expression was investigated by Western blotting assay. Luciferase reporter assay was used to assess if lncRNA TUG1 can bind to miR-129-5p and if miR-129-5p can target AEG1 mRNA. CCK-8 and apoptosis assay were used to detect cell growth and apoptosis. The metastasis of melanoma cells was detected by wound-healing and Transwell assays. The effects of TUG1 on growth of melanoma in vivo and cell chemoresistance were investigated via xenograft animal experiment and CCK-8 assay. RESULTS The expression of TUG1 and AEG1 was elevated and the miR-129-5p level was decreased in melanoma specimens and cell lines. Downregulation of either TUG1 or AEG1 suppressed cell growth and metastasis. miR-129-5p can bind directly to AEG1 and TUG1 can directly sponge miR-129-5p. Inhibition of TUG1 expression suppressed the expression of Bcl-2, MMP-9, and cyclin D1, and raised the level of cleaved caspase3 by modulating AEG1 level in melanoma cells. Inhibition of TUG1 reduced the growth of tumors in vivo and improved the chemosensitivity of A375 cells to cisplatin and 5-FU. CONCLUSIONS Reduction of TUG1 level suppressed cell growth and metastasis by regulating AEG1 expression mediated by targeting miR-129-5p. Suppression of lnc TUG1 may be a promising therapeutic strategy in the treatment of malignant melanoma.

Targeting long non-coding RNA-TUG1 inhibits tumor growth and angiogenesis in hepatoblastoma.

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Dong, R; Liu, G-B; Liu, B-H; Chen, G; Li, K; Zheng, S; Dong, K-R

2016-06-30

Hepatoblastoma is the most common liver tumor of early childhood, which is usually characterized by unusual hypervascularity. Recently, long non-coding RNAs (lncRNA) have emerged as gene regulators and prognostic markers in several cancers, including hepatoblastoma. We previously reveal that lnRNA-TUG1 is upregulated in hepatoblastoma specimens by microarray analysis. In this study, we aim to elucidate the biological and clinical significance of TUG1 upregulation in hepatoblastoma. We show that TUG1 is significantly upregulated in human hepatoblastoma specimens and metastatic hepatoblastoma cell lines. TUG1 knockdown inhibits tumor growth and angiogenesis in vivo, and decreases hepatoblastoma cell viability, proliferation, migration, and invasion in vitro. TUG1, miR-34a-5p, and VEGFA constitutes to a regulatory network, and participates in regulating hepatoblastoma cell function, tumor progression, and tumor angiogenesis. Overall, our findings indicate that TUG1 upregulation contributes to unusual hypervascularity of hepatoblastoma. TUG1 is a promising therapeutic target for aggressive, recurrent, or metastatic hepatoblastoma.

The prognostic potential and carcinogenesis of long non-coding RNA TUG1 in human cholangiocarcinoma.

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Xu, Yi; Leng, Kaiming; Li, Zhenglong; Zhang, Fumin; Zhong, Xiangyu; Kang, Pengcheng; Jiang, Xingming; Cui, Yunfu

2017-09-12

Cholangiocarcinoma (CCA) is a fatal disease with increasing worldwide incidence and is characterized by poor prognosis due to its poor response to conventional chemotherapy or radiotherapy. Long non-coding RNAs (lncRNAs) play key roles in multiple human cancers, including CCA. Cancer progression related lncRNA taurine-up-regulated gene 1 (TUG1) was reported to be involved in human carcinomas. However, the impact of TUG1 in CCA is unclear. The aim of this study was to explore the expression pattern of TUG1 and evaluate its clinical significance as well as prognostic potential in CCA. In addition, the functional roles of TUG1 including cell proliferation, apoptosis, migration, invasion and epithelial-mesenchymal transition (EMT), were evaluated after TUG1 silencing. Our data demonstrated up-regulation of TUG1 in both CCA tissues and cell lines. Moreover, overexpression of TUG1 is linked to tumor size ( p =0.005), TNM stage ( p =0.013), postoperative recurrence ( p =0.036) and overall survival ( p =0.010) of CCA patients. Furthermore, down-regulation of TUG1 following RNA silencing reduced cell growth and increased apoptosis in CCA cells. Additionally, TUG1 suppression inhibited metastasis potential in vitro by reversing EMT. Overall, our results suggest that TUG1 may be a rational CCA-related prognostic factor and therapeutic target.

Long intergenic non-coding RNA TUG1 is overexpressed in urothelial carcinoma of the bladder.

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Han, Yonghua; Liu, Yuchen; Gui, Yaoting; Cai, Zhiming

2013-04-01

Long intergenic non-coding RNAs (lincRNAs) are a class of non-coding RNAs that regulate gene expression via chromatin reprogramming. Taurine Up-regulated Gene 1 (TUG1) is a lincRNA that is associated with chromatin-modifying complexes and plays roles in gene regulation. In this study, we determined the expression patterns of TUG1 and the cell proliferation inhibition and apoptosis induced by silencing TUG1 in urothelial carcinoma of the bladder. The expression levels of TUG1 were determined using Real-Time qPCR in a total of 44 patients with bladder urothelial carcinomas. Bladder urothelial carcinoma T24 and 5637 cells were transfected with TUG1 siRNA or negative control siRNA. Cell proliferation was evaluated using MTT assay. Apoptosis was determined using ELISA assay. TUG1 was up-regulated in bladder urothelial carcinoma compared to paired normal urothelium. High TUG1 expression levels were associated with high grade and stage carcinomas. Cell proliferation inhibition and apoptosis induction were observed in TUG1 siRNA-transfected bladder urothelial carcinoma T24 and 5637 cells. Our data suggest that lincRNA TUG1 is emerging as a novel player in the disease state of bladder urothelial carcinoma. TUG1 may have potential roles as a biomarker and/or a therapeutic target in bladder urothelial carcinoma. Copyright © 2012 Wiley Periodicals, Inc.

Down-regulation of long non-coding RNA TUG1 inhibits osteosarcoma cell proliferation and promotes apoptosis.

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Zhang, Qiang; Geng, Pei-Liang; Yin, Pei; Wang, Xiao-Lin; Jia, Jin-Peng; Yao, Jie

2013-01-01

To investigate the expression level of TUG1 and one of its transcript variants (n377360) in osteosarcoma cells and assess the role of TUG1 in proliferation and apoptosis in the U2OS cell line. TUG1 and n377360 expression levels in patients with osteosarcomas and the U2OS human osteosarcoma cell line were evaluated using real-time quantitative PCR. U2OS cells were transected with TUG1 and n377360 siRNA or non-targeting siRNA. MTS was performed to assess the cell proliferation and flow cytometry was applied to analyze apoptosis. We found significantly higher TUG1 and n377360 expression levels in osteosarcoma tissues compared with matched non-tumorous tissues. In line with this, suppression of TUG1 and n377360 expression by siRNA significantly impaired the cell proliferation potential of osteosarcoma cells. Furthermore, inhibition of TUG1 expression significantly promoted osteosarcoma cell apoptosis. The overexpression of TUG1 and n377360 in osteosarcoma specimens and the functional role of TUG1 and n377360 regarding cell proliferation and apoptosis in an osteosarcoma cell line provided evidence that the use of TUG1 or n377360 may be a viable but an as yet unexplored therapeutic strategy in tumors that over express these factors.

Die tug oor ampsdraers tydens die doleansie van 1886

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J. Visser

1986-06-01

Full Text Available In art 29 van die Nederlandse Geloofsbelydenis word bely: “Die merktekens om die ware Kerk te ken is die volgende: As die Kerk die suiwere prediking van die evangelie uitoefen, as dit die suiwer bediening van die sakramente gebruik soos Christus dit ingestel het, as die kerklike tug gebruik word om die sondes te straf.” Dit spreek vanself dat wanneer ampsdraers, aan wie Christus sy kudde toevertrou het (Hand 20 : 28, met leer en /of lewenswandel in sonde volhard en nie daarin met tug gestuit word nie, word die ware kerk nie gebou nie maar afgebreek. 0ns sal later in hierdie artikel aantoon hoedanig die suiwer tug oor ampsdraers, veral leertug, tydens die Doleansie tot skade van die kerk van Christus agterweë gebly het.

TUG1: a pivotal oncogenic long non-coding RNA of human cancers.

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Li, Zheng; Shen, Jianxiong; Chan, Matthew T V; Wu, William Ka Kei

2016-08-01

Long non-coding RNAs (lncRNAs) are a group greater than 200 nucleotides in length. An increasing number of studies has shown that lncRNAs play important roles in diverse cellular processes, including proliferation, differentiation, apoptosis, invasion and chromatin remodelling. In this regard, deregulation of lncRNAs has been documented in human cancers. TUG1 is a recently identified oncogenic lncRNA whose aberrant upregulation has been detected in different types of cancer, including B-cell malignancies, oesophageal squamous cell carcinoma, bladder cancer, hepatocellular carcinoma and osteosarcoma. In these malignancies, knock-down of TUG1 has been shown to suppress cell proliferation, invasion and/or colony formation. Interestingly, TUG1 has been found to be downregulated in non-small cell lung carcinoma, indicative of its tissue-specific function in tumourigenesis. Pertinent to clinical practice, TUG1 may act as a prognostic biomarker for tumours. In this review, we summarize current knowledge concerning the role of TUG1 in tumour progression and discuss mechanisms associated with it. © 2016 John Wiley & Sons Ltd.

TUG1 promotes osteosarcoma tumorigenesis by upregulating EZH2 expression via miR-144-3p.

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Cao, Jiaqing; Han, Xinyou; Qi, Xin; Jin, Xiangyun; Li, Xiaolin

2017-10-01

lncRNA-TUG1 (Taurine upregulated 1) is up-regulated and highly correlated with poor prognosis and disease status in osteosarcoma. TUG1 knockdown inhibits osteosarcoma cell proliferation, migration and invasion, and promotes apoptosis. However, its mechanism of action has not been well addressed. Growing evidence documented that lncRNA works as competing endogenous (ce)RNAs to modulate the expression and biological functions of miRNA. As a putative combining target of TUG1, miR-144-3p has been associated with the progress of osteosarcoma. To verify whether TUG1 functions through regulating miR-144-3p, the expression levels of TUG1 and miR-144-3p in osteosarcoma tissues and cell lines were determined. TUG1 was upregulated in osteosarcoma tissues and cell lines, and negatively correlated with miR-144-3p. TUG1 knockdown induced miR-144-3p expression in MG63 and U2OS cell lines. Results from dual luciferase reporter assay, RNA-binding protein immuno-precipitation (RIP) and applied biotin-avidin pull-down system confirmed TUG1 regulated miR-144-3p expression through direct binding. EZH2, a verified target of miR-144-3p was upregulated in osteosarcoma tissues and negatively correlated with miR-144-3p. EZH2 was negatively regulated by miR-144-3p and positively regulated by TUG1. Gain-and loss-of-function experiments were performed to analyze the role of TUG1, miR-144-3p and EZH2 in the migration and EMT of osteosarcoma cells. EZH2 over-expression partly abolished TUG1 knockdown or miR-144-3p overexpression induced inhibition of migration and EMT in osteosarcoma cells. In addition, TUG1 knockdown represses the activation of Wnt/β-catenin pathway, which was reversed by EZH2 over-expression. The activator of Wnt/β-catenin pathway LiCl could partially block the TUG1-knockdown induced osteosarcoma cell migration and EMT inhibition. In conclusion, our results showed that TUG1 plays an important role in osteosarcoma development through miRNA-144-3p/EZH2/Wnt/β-catenin pathway.

Lightweight Space Tug body structure

International Nuclear Information System (INIS)

Lager, J.R.

1976-01-01

Lightweight honeycomb sandwich construction using a wide variety of metal and fibrous composite faceskins was used in the design of a typical Space Tug skirt structure. Relatively low magnitude combined loading of axial compression and torsion resulted in designs using ultrathin faceskins, light-weight honeycomb cores, and thin faceskin/core adhesive bond layers. Two of the designs with metal faceskins (aluminum and titanium) and four with fibrous composite faceskins (using combinations of fiberglass, boron, and graphite) were evaluated through the fabrication and structural test of a series of small development panels. The two most promising concepts with aluminum and graphite/epoxy faceskins, were further evaluated through the fabrication and structural test of larger compression and shear panels. All panels tested exceeded design ultimate load levels, thereby, verifying the structural integrity of the selected designs. Projected skirt structural weights for the graphite/epoxy and aluminum concepts fall within original weight guidelines established for the Space Tug vehicle

Upregulation of long noncoding RNA TUG1 promotes cervical cancer cell proliferation and migration.

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Hu, Yingying; Sun, Xiangwei; Mao, Chenchen; Guo, Gangqiang; Ye, Sisi; Xu, Jianfeng; Zou, Ruanmin; Chen, Jun; Wang, Ledan; Duan, Ping; Xue, Xiangyang

2017-02-01

Long noncoding RNAs (lncRNAs), a novel class of transcripts that have critical roles in carcinogenesis and progression, have emerged as important gene expression modulators. Recent evidence indicates that lncRNA taurine-upregulated gene 1 (TUG1) functions as an oncogene in numerous types of human cancers. However, its function in the development of cervical cancer remains unknown. The aim of this research was to investigate the clinical significance and biological functions of TUG1 in cervical cancer. TUG1 was found to be significantly upregulated in cervical cancer tissues and four cervical cancer cell lines by quantitative real-time polymerase chain reaction (qRT-PCR). Elevated TUG1 expression was correlated with larger tumor size, advanced international federation of gynecology and obstetrics (FIGO) stage, poor differentiation, and lymph node metastasis. Furthermore, knockdown of TUG1 suppressed cell proliferation with activation of apoptosis, in part by regulating the expression of Bcl-2 and caspase-3. Silencing of TUG1 inhibited cell migration and invasion via the progression of epithelial-mesenchymal transition (EMT). Taken together, our findings indicate that TUG1 acts as an oncogene in cervical cancer and may represent a novel therapeutic target. © 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

LncRNA TUG1 is upregulated and promotes cell proliferation in osteosarcoma

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Yun-Bo, Feng; Xiao-Po, Liu; Xiao-Li, Li; Guo-Long, Cao; Pei, Zhang; Fa-Ming, Tian

2016-01-01

Abstract Objective: To examine the expression and function of long non-coding RNA taurine up-regulated 1 (TUG1) in human osteosarcoma cells. Methods: Real-time quantitive PCR was used to detect the transcription level of TUG1 in a series of osteosarcoma cell lines. Knockdown of TUG1 in U2OS cells was carried out by transient transfection of siRNAs. MTT assay was performed to access the cell growth rates. Afterwards, RNA and protein of these cells were extracted to analyze the transfection eff...

High TUG1 expression is associated with chemotherapy resistance and poor prognosis in esophageal squamous cell carcinoma.

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Jiang, Lin; Wang, Wenchao; Li, Guoli; Sun, Canlin; Ren, Zhenqin; Sheng, Haihui; Gao, Hengjun; Wang, Chaofu; Yu, Hong

2016-08-01

Long noncoding RNAs (lncRNAs) play critical roles in diverse biological processes such as tumorigenesis and metastasis. Taurine upregulated gene 1 (TUG1) is a cancer-related lncRNA that is associated with chromatin-modifying complexes and plays an important role in gene regulation. In this study, we determined the expression patterns of TUG1 in esophageal squamous cell carcinoma (ESCC) and evaluated its clinical significance. The expression level of TUG1 was examined in 218 pairs of ESCC and adjacent non-cancerous tissues by using quantitative real-time polymerase chain reaction. The relationship between TUG1 expression and clinical features and prognosis was statistically analyzed. The expression level of TUG1 was significantly upregulated in ESCC tissues compared with paired adjacent normal tissues. High TUG1 expression was significantly correlated with chemotherapy resistance. Survival analysis showed that patients with high TUG1 expression had poor prognosis, especially for cases with well and moderate differentiation, ulcerative type, smaller size, and chemotherapy-sensitive tumors. Our findings suggest that elevated TUG1 expression is related to chemotherapy resistance and may help predict a poor prognostic outcome of ESCC. TUG1 may provide a potential therapeutic target for ESCC.

Long non-coding RNA TUG1 can promote proliferation and migration of pancreatic cancer via EMT pathway.

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Qin, C-F; Zhao, F-L

2017-05-01

This paper aimed to investigate the effect of long non-coding RNA TUG1 (lncRNA TUG1) on cell proliferation, as well as cell migration in pancreatic cancer. The mRNA levels of Taurine-up-regulated gene 1 (TUG1) in three kinds of pancreatic cancer cells BxPC3, PaTu8988 and SW1990 was detected by RT-qPCR. Meantime, RT-qPCR was used to examine the mRNA levels of TUG1 in 20 cases of human pancreatic cancer tissues and its para-carcinoma tissues. pCDH-TUG1 plasmid and its empty plasmid pCDH were transfected into BxPC3 and PaTu8988 cells to up-regulate TUG1 expression. siRNA targeting TUG1 and the control siRNA were transfected into SW1990 cells to down-regulate TUG1 expression. Cell clone formation and CCK-8 assay were used to detect the cell proliferation capacity. Transwell assay was used to evaluate cell migration capacity. Western blot was applied to examine the protein expressions of MMP2, MMP9, E-cadherin, Smad 2, Smad 3, p-Smad 2, p-Smad 3, TGF-β and TGF-βR. RT-qPCR was used to detect the levels of MMP2 and MMP9. The results showed that TUG1 was differentially expressed in the three kinds of pancreatic cancer cells, among which the expression level of SW1990 was relatively high, and the expression levels of BxPC3 and PaTu8988 were relatively low. TUG1 had more expression in pancreatic cancer tissues than that in para-carcinoma tissues. After the up-regulation of TUG1, cell proliferation and migration capacities were increased, protein levels of MMP2 and MMP9 were increased and protein level of E-cadherin was declined. Conversely, after down-regulation of TUG1 expression, cell proliferation and migration capacities were weakened, protein levels of MMP2 and MMP9 were decreased and protein level of E-cadherin was increased. In addition, over-expressed TUG1 could promote Smad2 and Smad3 phosphorylation, but Smad2 and Smad3 phosphorylation were weakened after down-regulated expression of TUG1. The protein expression of TGF-β and TGF-β receptor were more in the TUG1

Long Non-Coding RNA TUG1 Expression Is Associated with Different Subtypes in Human Breast Cancer.

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Gradia, Daniela F; Mathias, Carolina; Coutinho, Rodrigo; Cavalli, Iglenir J; Ribeiro, Enilze M S F; de Oliveira, Jaqueline C

2017-12-20

Taurine upregulated 1 gene ( TUG1 ) is a long non-coding RNA associated with several types of cancer. Recently, differential expression of TUG1 was found in cancerous breast tissues and associated with breast cancer malignancy features. Although this is evidence of a potential role in breast cancer, TUG1 expression could not be associated with different subtypes, possibly due to the small number of samples analyzed. Breast cancer is a heterogeneous disease and, based on molecular signatures, may be classified into different subtypes with prognostic implications. In the present study, we include analysis of TUG1 expression in 796 invasive breast carcinoma and 105 normal samples of RNA sequencing (RNA-seq) datasets from The Cancer Genome Atlas (TCGA) and describe that TUG1 expression is increased in HER2-enriched and basal-like subtypes compared to luminal A. Additionally, TUG1 expression is associated with survival in HER2-enriched patients. These results reinforce the importance of TUG1 in breast cancer and outline its potential impact on specific subtypes.

Long Non-Coding RNA TUG1 Expression Is Associated with Different Subtypes in Human Breast Cancer

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Daniela F. Gradia

2017-12-01

Full Text Available Taurine upregulated 1 gene (TUG1 is a long non-coding RNA associated with several types of cancer. Recently, differential expression of TUG1 was found in cancerous breast tissues and associated with breast cancer malignancy features. Although this is evidence of a potential role in breast cancer, TUG1 expression could not be associated with different subtypes, possibly due to the small number of samples analyzed. Breast cancer is a heterogeneous disease and, based on molecular signatures, may be classified into different subtypes with prognostic implications. In the present study, we include analysis of TUG1 expression in 796 invasive breast carcinoma and 105 normal samples of RNA sequencing (RNA-seq datasets from The Cancer Genome Atlas (TCGA and describe that TUG1 expression is increased in HER2-enriched and basal-like subtypes compared to luminal A. Additionally, TUG1 expression is associated with survival in HER2-enriched patients. These results reinforce the importance of TUG1 in breast cancer and outline its potential impact on specific subtypes.

Long non-coding RNA TUG1 acts as a miR-26a sponge in human glioma cells.

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Li, Jun; An, Gang; Zhang, Meng; Ma, Qingfang

2016-09-02

Long non-coding RNA taurine upregulated gene 1 (TUG1) acts as an important regulator in cancer pathogenesis; however, its functional mechanism in glioma development remains unclear. This study aims to explore the potential function of TUG1 in glioma by sponging miR-26a. The expression of TUG1, miR-26a, and phosphatase and tensin homolog (PTEN) in 20 paired glioma tissues was detected by quantitative real-time PCR and subjected to correlation analysis. Bioinformatics analysis was performed by using DIANA Tools. Abnormal TUG1 expression was conducted in two glioma cells to analyze its regulation on miR-26a and PTEN using real-time PCR, western blot, and luciferase reporter assay. TUG1 expression was confirmed to be upregulated in glioma tissues, and showed an inverse correlation with downregulated miR-26a. TUG1 could negatively regulate the expression of miR-26a in glioma cells. The bioinformatics prediction revealed putative miR-26a binding sites within TUG1 transcripts. Further experiments demonstrated the positive regulation of TUG1 on the miR-26a target, PTEN, wherein TUG1 could inhibit the negative regulation of miR-26a on PTEN by binding its 3'UTR. Additionally, the expression of PTEN was also upregulated in glioma tissues, showing a positive or negative correlation with TUG1 or miR-26a, respectively. TUG1 could serve as a miR-26a sponge in human glioma cells, contributing to the upregulation of PTEN. This study revealed a new TUG1/miR-26a/PTEN regulatory mechanism and provided a further understanding of the tumor-suppressive role of TUG1 in glioma development. Copyright © 2016 Elsevier Inc. All rights reserved.

Targeting the Notch-regulated non-coding RNA TUG1 for glioma treatment.

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Katsushima, Keisuke; Natsume, Atsushi; Ohka, Fumiharu; Shinjo, Keiko; Hatanaka, Akira; Ichimura, Norihisa; Sato, Shinya; Takahashi, Satoru; Kimura, Hiroshi; Totoki, Yasushi; Shibata, Tatsuhiro; Naito, Mitsuru; Kim, Hyun Jin; Miyata, Kanjiro; Kataoka, Kazunori; Kondo, Yutaka

2016-12-06

Targeting self-renewal is an important goal in cancer therapy and recent studies have focused on Notch signalling in the maintenance of stemness of glioma stem cells (GSCs). Understanding cancer-specific Notch regulation would improve specificity of targeting this pathway. In this study, we find that Notch1 activation in GSCs specifically induces expression of the lncRNA, TUG1. TUG1 coordinately promotes self-renewal by sponging miR-145 in the cytoplasm and recruiting polycomb to repress differentiation genes by locus-specific methylation of histone H3K27 via YY1-binding activity in the nucleus. Furthermore, intravenous treatment with antisense oligonucleotides targeting TUG1 coupled with a drug delivery system induces GSC differentiation and efficiently represses GSC growth in vivo. Our results highlight the importance of the Notch-lncRNA axis in regulating self-renewal of glioma cells and provide a strong rationale for targeting TUG1 as a specific and potent therapeutic approach to eliminate the GSC population.

Downregulation of lncRNA TUG1 Affects Apoptosis and Insulin Secretion in Mouse Pancreatic β Cells

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Dan-dan Yin

2015-03-01

Full Text Available Background: Increasing evidence indicates that long noncoding RNAs (IncRNAs perform specific biological functions in diverse processes. Recent studies have reported that IncRNAs may be involved in β cell function. The aim of this study was to characterize the role of IncRNA TUG1 in mouse pancreatic β cell functioning both in vitro and in vivo. Methods: qRT-PCR analyses were performed to detect the expression of lncRNA TUG1 in different tissues. RNAi, MTT, TUNEL and Annexin V-FITC assays and western blot, GSIS, ELISA and immunochemistry analyses were performed to detect the effect of lncRNA TUG1 on cell apoptosis and insulin secretion in vitro and in vivo. Results: lncRNA TUG1 was highly expressed in pancreatic tissue compared with other organ tissues, and expression was dynamically regulated by glucose in Nit-1 cells. Knockdown of lncRNA TUG1 expression resulted in an increased apoptosis ratio and decreased insulin secretion in β cells both in vitro and in vivo . Immunochemistry analyses suggested decreased relative islet area after treatment with lncRNA TUG1 siRNA. Conclusion: Downregulation of lncRNA TUG1 expression affected apoptosis and insulin secretion in pancreatic β cells in vitro and in vivo. lncRNA TUG1 may represent a factor that regulates the function of pancreatic β cells.

Downregulation of lncRNA TUG1 affects apoptosis and insulin secretion in mouse pancreatic β cells.

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Yin, Dan-dan; Zhang, Er-bao; You, Liang-hui; Wang, Ning; Wang, Lin-tao; Jin, Fei-yan; Zhu, Ya-nan; Cao, Li-hua; Yuan, Qing-xin; De, Wei; Tang, Wei

2015-01-01

Increasing evidence indicates that long noncoding RNAs (IncRNAs) perform specific biological functions in diverse processes. Recent studies have reported that IncRNAs may be involved in β cell function. The aim of this study was to characterize the role of IncRNA TUG1 in mouse pancreatic β cell functioning both in vitro and in vivo. qRT-PCR analyses were performed to detect the expression of lncRNA TUG1 in different tissues. RNAi, MTT, TUNEL and Annexin V-FITC assays and western blot, GSIS, ELISA and immunochemistry analyses were performed to detect the effect of lncRNA TUG1 on cell apoptosis and insulin secretion in vitro and in vivo. lncRNA TUG1 was highly expressed in pancreatic tissue compared with other organ tissues, and expression was dynamically regulated by glucose in Nit-1 cells. Knockdown of lncRNA TUG1 expression resulted in an increased apoptosis ratio and decreased insulin secretion in β cells both in vitro and in vivo . Immunochemistry analyses suggested decreased relative islet area after treatment with lncRNA TUG1 siRNA. Downregulation of lncRNA TUG1 expression affected apoptosis and insulin secretion in pancreatic β cells in vitro and in vivo. lncRNA TUG1 may represent a factor that regulates the function of pancreatic β cells. © 2015 S. Karger AG, Basel.

Down-regulation of LncRNA TUG1 enhances radiosensitivity in bladder cancer via suppressing HMGB1 expression.

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Jiang, Huijuan; Hu, Xigang; Zhang, Hongzhi; Li, Wenbo

2017-04-04

Long non-coding RNAs (lncRNAs) have been reported to regulate the sensitivity of different cancer cells to chemoradiotherapy. Aberrant expression of lncRNA Taurine-upregulated gene 1 (TUG1) has been found to be involved in the development of bladder cancer, however, its function and underlying mechanism in the radioresistance of bladder cancer remains unclear. Quantitative real-time PCR (qRT-PCR) was conducted to measure the expression of TUG1 and HMGB1 mRNA in bladder cancer tissues and cell lines. HMGB1 protein levels were tested by western blot assays. Different doses of X-ray were used for radiation treatment of bladder cancer cells. Colony survival and cell viability were detected by clonogenic assay and CCK-8 Kit, respectively. Cell apoptosis was determined by flow cytometry. A xenograft mouse model was constructed to observe the effect of TUG1 on tumor growth in vivo. The levels of TUG1 and HMGB1 were remarkably increased in bladder cancer tissues and cell lines. Radiation treatment markedly elevated the expression of TUG1 and HMGB1. TUG1 knockdown inhibited cell proliferation, promoted cell apoptosis and decreased colony survival in SW780 and BIU87 cells under radiation. Moreover, TUG1 depletion suppressed the HMGB1 mRNA and protein levels. Furthermore, overexpression of HMGB1 reversed TUG1 knockdown-induced effect in bladder cancer cells. Radiation treatment dramatically reduced the tumor volume and weight in xenograft model, and this effect was more obvious when combined with TUG1 silencing. LncRNA TUG1 knockdown enhances radiosensitivity of bladder cancer by suppressing HMGB1 expression. TUG1 acts as a potential regulator of radioresistance of bladder cancer, and it may represent a promising therapeutic target for bladder cancer patients.

Verifying Safety Messages Using Relative-Time and Zone Priority in Vehicular Ad Hoc Networks

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Banani, Sam; Thiemjarus, Surapa; Kittipiyakul, Somsak

2018-01-01

In high-density road networks, with each vehicle broadcasting multiple messages per second, the arrival rate of safety messages can easily exceed the rate at which digital signatures can be verified. Since not all messages can be verified, algorithms for selecting which messages to verify are required to ensure that each vehicle receives appropriate awareness about neighbouring vehicles. This paper presents a novel scheme to select important safety messages for verification in vehicular ad hoc networks (VANETs). The proposed scheme uses location and direction of the sender, as well as proximity and relative-time between vehicles, to reduce the number of irrelevant messages verified (i.e., messages from vehicles that are unlikely to cause an accident). Compared with other existing schemes, the analysis results show that the proposed scheme can verify messages from nearby vehicles with lower inter-message delay and reduced packet loss and thus provides high level of awareness of the nearby vehicles. PMID:29652840

Prognostic significance of overexpressed long non-coding RNA TUG1 in patients with clear cell renal cell carcinoma.

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Wang, P-Q; Wu, Y-X; Zhong, X-D; Liu, B; Qiao, G

2017-01-01

The long non-coding RNAs (lncRNAs) study has gradually become one of the hot topics in the field of RNA biology. However, little is known about the pathological role of lncRNA TUG1 in clear cell renal cell carcinoma (ccRCC) patients. This study attempted to investigate the association of lncRNA TUG1 expression with progression and prognosis in ccRCC patients. Using qRT-PCR, the expression of TUG1 was measured in 203 ccRCC tissues and 45 adjacent non-cancerous tissues. Then, the relationships between TUG1 level and the clinicopathological factors of patients with ccRCC were analyzed. The prognostic significance was evaluated using Kaplan-Meier and Cox regression analyses. The relative level of TUG1was significantly higher in ccRCC tissues compared to the adjacent non-tumor tissues (p TUG1 was associated significantly with histological grade, tumor stage, lymph node metastasis and distant metastasis (all p TUG1 expression levels were associated with a shorter overall survival (p TUG1 expression was an independent prognostic marker of poor outcome. These findings suggested that TUG1 may act as a tumor promoter in ccRCC and could serve as a potential therapeutic target for this tumor.

Navigation simulator for the Space Tug vehicle

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Colburn, B. K.; Boland, J. S., III; Peters, E. G.

1977-01-01

A general simulation program (GSP) for state estimation of a nonlinear space vehicle flight navigation system is developed and used as a basis for evaluating the performance of a Space Tug navigation system. An explanation of the iterative guidance mode (IGM) guidance law, derivation of the dynamics, coordinate frames and state estimation routines are given in order to clarify the assumptions and approximations made. A number of simulation and analytical studies are used to demonstrate the operation of the Tug system. Included in the simulation studies are (1) initial offset vector parameter study; (2) propagation time vs accuracy; (3) measurement noise parametric study and (4) reduction in computational burden of an on-board implementable scheme. From the results of these studies, conclusions and recommendations concerning future areas of practical and theoretical work are presented.

Upregulation of long non-coding RNA TUG1 correlates with poor prognosis and disease status in osteosarcoma.

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Ma, Bing; Li, Meng; Zhang, Lei; Huang, Ming; Lei, Jun-Bin; Fu, Gui-Hong; Liu, Chun-Xin; Lai, Qi-Wen; Chen, Qing-Quan; Wang, Yi-Lian

2016-04-01

The pathogenesis of osteosarcoma involves complex genetic and epigenetic factors. This study was to explore the impact and clinical relevance of long non-coding RNA (lncRNA), Taurine up-regulated gene 1 (TUG1) on patients with osteosarcoma. Seventy-six osteosarcoma tissues and matched adjacent normal tissues were included for analysis. The plasma samples were obtained from 29 patients with osteosarcoma at pre-operation and post-operation, 42 at newly diagnosed, 18 who experienced disease progression or relapse, 45 post-treatment, 36 patients with benign bone tumor, and 20 healthy donors. Quantitative real-time reverse transcript polymerase chain reactions were used to assess the correlation of the expression levels of TUG1 with clinical parameters of osteosarcoma patients. TUG1 was significantly overexpressed in the osteosarcoma tissues compared with matched adjacent normal tissues (P TUG1 strongly correlated with poor prognosis and was an independent prognostic indicator for overall survival (HR = 2.78, 95% CI = 1.29-6.00, P = 0.009) and progression-free survival (HR = 1.81, 95% CI = 1.01-3.54, P = 0.037). Our constructed nomogram containing TUG1 had more predictive accuracy than that without TUG1 (c-index 0.807 versus 0.776, respectively). In addition, for plasma samples, TUG1 expression levels were obviously decreased in post-operative patients (mean ΔCT -4.98 ± 0.22) compared with pre-operation patients (mean ΔCT -6.09 ± 0.74), and the changes of TUG1 expression levels were significantly associated with disease status. Receiver operating characteristic (ROC) curve analysis demonstrated that TUG1 could distinguish patients with osteosarcoma from healthy individuals compared with alkaline phosphatase (ALP) (the area under curve 0.849 versus 0.544). TUG1 was overexpressed in patients with osteosarcoma and strongly correlated with disease status. In addition, TUG1 may serve as a molecular indicator in maintaining surveillance

From Campus Tug-of-War to Pulling Together: Using the Lean Approach

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MacIntyre, Stephen; Meade, Kelly; McEwen, Melissa

2009-01-01

Some days seem like bouts in an endless game of tug-of-war. At one end of the rope, facilities professionals must do more--tackle deferred maintenance, develop a climate strategy, and meet the energy and operational needs for a complex mix of building types and stakeholders. Tugging on the other end are the obstacles of less money, staff, and…

Long non-coding RNA TUG1 as a potential prognostic biomarker in human cancers: a meta-analysis.

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Ma, Peng-Ju; Guan, Qing-Kai; Meng, Lei; Qin, Nan; Zhao, Jia; Jin, Bao-Zhe

2017-09-22

LncRNA taurine upregulated gene 1 (TUG1) is reportedly dysregulated in various cancers. We performed this meta-analysis to clarify the usefulness of TUG1 as a prognostic marker in malignant tumors. The PubMed, Medline, OVID, Cochrane Library, and Web of Science databases were searched from inception to Jan 11, 2017. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to explore the relationship between TUG1 expression and overall survival (OS). Odds ratios (ORs) were calculated to assess the association between TUG1 expression and pathological parameters. Thirteen original studies covering 1,274 cancer patients were included in this meta-analysis. The pooled HR suggested that high TUG1 expression correlated with poor OS (pooled HR=1.41, 95% CI: 1.01-1.98) in cancer types other than non-small cell lung cancer. TUG1 expression was also related to distant metastasis (OR=3.24, 95% CI: 1.18-8.93), large tumor size (OR=4.07, 95% CI: 1.08-15.28) and advanced tumor stage (OR=3.45, 95% CI: 2.19-5.44). Begg's funnel plot and Egger's test showed no evidence of obvious asymmetry for overall survival or tumor stage. Thus high TUG1 expression appears predictive of poor OS, distant metastasis, advanced tumor stage and large tumor size. This suggests TUG1 expression could serve as a biomarker for poor prognosis in cancers.

The lncRNA TUG1 modulates proliferation in trophoblast cells via epigenetic suppression of RND3.

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Xu, Yetao; Ge, Zhiping; Zhang, Erbao; Zuo, Qing; Huang, Shiyun; Yang, Nana; Wu, Dan; Zhang, Yuanyuan; Chen, Yanzi; Xu, Haoqin; Huang, Huan; Jiang, Zhiyan; Sun, Lizhou

2017-10-12

Due to limited treatment options, pre-eclampsia (PE) is associated with fetal perinatal and maternal morbidity and mortality. During the causes of PE, failure of uterine spiral artery remodeling which might be related to functioning abnormally of trophoblast cells, result in the occurrence and progression of PE. Recently, abnormal expression of long non-coding RNAs (lncRNAs), as imperative regulators involved in human diseases progression (included PE), which has been indicated by increasing evidence. In this research, we found that TUG1, a lncRNA, was markedly reduced in placental samples from patients with PE. Loss-function assays indicated that knockdown TUG1 significantly affected cell proliferation, apoptosis, migration and network formation in vitro. RNA-seq revealed that TUG1 could affect abundant genes, and then explore the function and regulatory mechanism of TUG1 in trophoblast cells. Furthermore, RNA immunoprecipitation and chromatin immunoprecipitation assays validated that TUG1 can epigenetically inhibit the level of RND3 through binding to EZH2, thus promoting PE development. Therefore, via illuminating the TUG1 mechanisms underlying PE development and progression, our findings might furnish a prospective therapeutic strategy for PE intervention.

Long non-coding RNA TUG1 regulates ovarian cancer proliferation and metastasis via affecting epithelial-mesenchymal transition.

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Kuang, Defeng; Zhang, Xiaoping; Hua, Shaofang; Dong, Wei; Li, Zhiguo

2016-10-01

Ovarian cancer is the fifth leading cause of cancer-related death in women worldwide, and recent studies have highlighted the role of long non-coding RNAs (lncRNAs) in cancer development. However, the role of lncRNAs in ovarian cancer is largely unclear. In this study, we focused on the taurine up-regulated gene 1 (TUG1) and examined its molecular mechanism in ovarian cancer. Here, we reported that TUG1 was up-regulated in ovarian cancer tissues and ovarian cancer cells, and TUG1 expression was positively correlated with tumor grade and FIGO stage. In vitro functional assays (CCK-8 assay, colony formation assay, and cell invasion assay) revealed that knock-down of TUG1 by small RNA inference significantly inhibited cell proliferation, colony formation and cell invasion in ovarian cancer cells. Further experiment showed that knock-down of TUG1 induced cell apoptosis and altered the protein expression levels of apoptosis-related mediators in ovarian cancer cells. More importantly, knock-down of TUG1 also reversed epithelial-mesenchymal transition in ovarian cancer. In summary, our results suggest that knock-down of TUG1 may represent a novel therapeutic strategy for the treatment of ovarian cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

Long noncoding RNA TUG1 is downregulated in non-small cell lung cancer and can regulate CELF1 on binding to PRC2.

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Lin, Pei-Chin; Huang, Hsien-Da; Chang, Chun-Chi; Chang, Ya-Sian; Yen, Ju-Chen; Lee, Chien-Chih; Chang, Wen-Hsin; Liu, Ta-Chih; Chang, Jan-Gowth

2016-08-02

Long noncoding RNAs (lncRNAs) play crucial roles in tumorigenesis, and lncRNA taurine-upregulated gene 1 (TUG1) has been proven to be associated with several human cancers. However, the mechanisms of TUG1-involved regulation remain largely unknown. We examined the expressions of TUG1 in a cohort of 89 patients with non-small cell lung cancer (NSCLC) to determine the association between TUG1 expression and clinical parameters. We used circular chromosome conformation capture (4C) coupled with next-generation sequencing to explore the genome regions that interact with TUG1 and the TUG1-mediated regulation. TUG1 was significantly downregulated, and the TUG1 downregulation correlated with sex (p = 0.006), smoking status (p = 0.016), and tumor differentiation grade (p = 0.001). Knockdown of TUG1 significantly promoted the proliferation of NSCLC cells. According to the bioinformatic analysis result of TUG1 4C sequencing data, 83 candidate genes and their interaction regions were identified. Among these candidate genes, CUGBP and Elav-like family member 1 (CELF1) are potential targets of TUG1 in-trans regulation. To confirm the interaction between TUG1 and CELF1, relative expressions of CELF1 were examined in TUG1 knockdown H520 cells; results showed that CELF1 was significantly upregulated in TUG1 knockdown H520 cells. RNA immunoprecipitation was then performed to examine whether TUG1 RNA was bound to PRC2, a TUG1-involved regulation mechanism reported in previous studies. The results demonstrated that TUG1 RNA was bound to enhancer of zeste protein 2/embryonic ectoderm development (EZH2/EED), which is essential for PRC2. Finally, our designed ChIP assay revealed that the EZH2/EED was bound to the promotor region of CELF1 within 992 bp upstream of the transcript start site. TUG1 is downregulated in NSCLC. Using TUG1 4C sequencing and bioinformatic analysis, we found CELF1 to be a potential target of TUG1 RNA in in-trans regulation. Moreover, subsequent

Long non-coding RNA TUG1 promotes cell proliferation and metastasis by negatively regulating miR-300 in gallbladder carcinoma.

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Ma, Fei; Wang, Shou-Hua; Cai, Qiang; Jin, Long-Yang; Zhou, Di; Ding, Jun; Quan, Zhi-Wei

2017-04-01

As we all know, long non-coding RNAs (lncRNAs) have been reported to play vital roles in various human cancers. In this study, we aimed to explore the role of lncRNA TUG1 in gallbladder carcinoma (GBC) development. Total RNA was extracted from the tissues of thirty GBC patients, four GBC cell lines. We detected the expression levels of TUG1 using quantitative real-time PCR. We performed CCK8, colony formation, transwell invasion and apoptosis assays to study the effects of TUG1 on GBC cell proliferation and invasion. Western blot assay was performed to assess to the expression level of epithelial-mesenchymal transition (EMT) markers in transforming growth factor-β1 (TGF-β1) treated and TUG1 knockdown GBC cell. Lastly, dual-luciferase reporter assay and quantitative real-time PCR were performed to verify the potential target microRNAs (miRNAs) of TUG1. TUG1 expression was significantly overexpressed in GBC tissues. Functionally, this study demonstrated that knockdown of TUG1 significantly inhibited GBC cell proliferation, metastasis. Mechanically, we found that TUG1 is upregulated by TGF-β1, and knockdown of TUG1 inhibited GBC cell EMT. Furthermore, we identified that miR-300, which has been reported as a suppressor in other types of cancer, is negatively regulated by TUG1. LncRNA TUG1 promotes GBC cell proliferation, metastasis and EMT progression by functioning as a miRNA sponge to abrogate the endogenous effect of miR-300. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Prognostic role of long non-coding RNA TUG1 expression in various cancers: a meta-analysis.

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Zhou, Yongping; Lu, Yuxuan; Li, Runmin; Yan, Nana; Li, Xiding; Dai, Tu

2017-11-21

Several studies were conducted to explore the prognostic role of long non-coding RNA taurine upregulated gene 1 (lncRNA TUG1) expression in various cancers, with contradictory. This study aims to summarize the prognostic role of lncRNA TUG1 expression in various cancers. Embase, PubMed and Cochrane Library were completely retrieved. The cohort studies focusing on the prognostic role of lncRNA TUG1 expression in various cancers were eligible. The endpoints were overall survival (OS) and clinicopathological parameters. 9 studies involving a total of 1,078 patients were identified. The results showed that high lncRNA TUG1 expression was obviously associated with worse OS when compared to the low lncRNA TUG1 expression (HR = 1.37, 95% CI = 1.07-1.76, P = 0.01; I 2 = 85%). However, No distinct relationship was observed between the lncRNA TUG1 expression and age (OR = 0.99, 95% CI = 0.76-1.28, P = 0.92; I2 = 4%), gender (OR = 0.92, 95% CI = 0.70-1.22, P = 0.57; I 2 = 0%), diameter (OR = 0.83, 95% CI = 0.34-2.01, P = 0.67; I 2 = 85%), smoking (OR = 1.09, 95% CI = 0.37-3.21, P = 0.87; I 2 = 73%), TNM stage (OR = 0.60, 95% CI = 0.25-1.43, P = 0.25; I 2 = 86%) and lymph node metastasis (OR = 1.07, 95% CI = 0.47-2.45, P = 0.87; I 2 = 86%). In conclusion, it was revealed that high lncRNA TUG1 expression is an unfavorable predictor of OS in patients with cancers, and lncRNA TUG1 expression is a promising prognostic biomarker for various cancers.

The Lncrna-TUG1/EZH2 Axis Promotes Pancreatic Cancer Cell Proliferation, Migration and EMT Phenotype Formation Through Sponging Mir-382.

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Zhao, Liang; Sun, Hongwei; Kong, Hongru; Chen, Zongjing; Chen, Bicheng; Zhou, Mengtao

2017-01-01

Pancreatic carcinoma (PC) is the one of the most common and malignant cancers worldwide. LncRNA taurine upregulated gene 1 (TUG1) was initially identified as a transcript upregulated by taurine, and the abnormal expression of TUG1 has been reported in many cancers. However, the biological role and molecular mechanism of TUG1 in PC still needs further investigation. Quantitative real-time PCR (qRT-PCR) was performed to measure the expression of TUG1 in PC cell lines and tissues. MTT and colony formation assays were used to measure the effect of TUG1 on cell proliferation. A wound healing assay, transwell assay and western blot assay were employed to determine the effect of TUG1 on cell migration and the epithelial mesenchymal transition (EMT) phenotype. RNA-binding protein immunoprecipitation (RIP) and a biotin-avidin pulldown system were performed to confirm the interaction between miR-328 and TUG1. A gene expression array analysis using clinical samples and RT-qPCR suggested that enhancer of zeste homolog 2 (EZH2) was a target of miR-382 in PC. In this study, we reported that TUG1 was overexpressed in PC tissues and cell lines, and high expression of TUG1 predicted poor prognosis. Further experiments revealed that overexpressed TUG1 promoted cell proliferation, migration and contributed to EMT formation, whereas silenced TUG1 led to opposing results. Additionally, luciferase reporter assays, an RIP assay and an RNA-pulldown assay demonstrated that TUG1 could competitively sponge miR-382 and thereby regulate EZH2. Collectively, these findings revealed that TUG1 functions as an oncogenic lncRNA that promotes tumor progression, at least partially, by functioning as an endogenous 'sponge' and competing for miR-382 binding to the miRNA target EZH2. © 2017 The Author(s). Published by S. Karger AG, Basel.

The Lncrna-TUG1/EZH2 Axis Promotes Pancreatic Cancer Cell Proliferation, Migration and EMT Phenotype Formation Through Sponging Mir-382

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Liang Zhao

2017-08-01

Full Text Available Background/Aims: Pancreatic carcinoma (PC is the one of the most common and malignant cancers worldwide. LncRNA taurine upregulated gene 1 (TUG1 was initially identified as a transcript upregulated by taurine, and the abnormal expression of TUG1 has been reported in many cancers. However, the biological role and molecular mechanism of TUG1 in PC still needs further investigation. Methods: Quantitative real-time PCR (qRT-PCR was performed to measure the expression of TUG1 in PC cell lines and tissues. MTT and colony formation assays were used to measure the effect of TUG1 on cell proliferation. A wound healing assay, transwell assay and western blot assay were employed to determine the effect of TUG1 on cell migration and the epithelial mesenchymal transition (EMT phenotype. RNA-binding protein immunoprecipitation (RIP and a biotin-avidin pulldown system were performed to confirm the interaction between miR-328 and TUG1. A gene expression array analysis using clinical samples and RT-qPCR suggested that enhancer of zeste homolog 2 (EZH2 was a target of miR-382 in PC. Results: In this study, we reported that TUG1 was overexpressed in PC tissues and cell lines, and high expression of TUG1 predicted poor prognosis. Further experiments revealed that overexpressed TUG1 promoted cell proliferation, migration and contributed to EMT formation, whereas silenced TUG1 led to opposing results. Additionally, luciferase reporter assays, an RIP assay and an RNA-pulldown assay demonstrated that TUG1 could competitively sponge miR-382 and thereby regulate EZH2. Conclusion: Collectively, these findings revealed that TUG1 functions as an oncogenic lncRNA that promotes tumor progression, at least partially, by functioning as an endogenous ‘sponge’ and competing for miR-382 binding to the miRNA target EZH2.

Long noncoding RNA TUG1 is downregulated in non-small cell lung cancer and can regulate CELF1 on binding to PRC2

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Lin, Pei-Chin; Huang, Hsien-Da; Chang, Chun-Chi; Chang, Ya-Sian; Yen, Ju-Chen; Lee, Chien-Chih; Chang, Wen-Hsin; Liu, Ta-Chih; Chang, Jan-Gowth

2016-01-01

Long noncoding RNAs (lncRNAs) play crucial roles in tumorigenesis, and lncRNA taurine-upregulated gene 1 (TUG1) has been proven to be associated with several human cancers. However, the mechanisms of TUG1-involved regulation remain largely unknown. We examined the expressions of TUG1 in a cohort of 89 patients with non-small cell lung cancer (NSCLC) to determine the association between TUG1 expression and clinical parameters. We used circular chromosome conformation capture (4C) coupled with next-generation sequencing to explore the genome regions that interact with TUG1 and the TUG1-mediated regulation. TUG1 was significantly downregulated, and the TUG1 downregulation correlated with sex (p = 0.006), smoking status (p = 0.016), and tumor differentiation grade (p = 0.001). Knockdown of TUG1 significantly promoted the proliferation of NSCLC cells. According to the bioinformatic analysis result of TUG1 4C sequencing data, 83 candidate genes and their interaction regions were identified. Among these candidate genes, CUGBP and Elav-like family member 1 (CELF1) are potential targets of TUG1 in-trans regulation. To confirm the interaction between TUG1 and CELF1, relative expressions of CELF1 were examined in TUG1 knockdown H520 cells; results showed that CELF1 was significantly upregulated in TUG1 knockdown H520 cells. RNA immunoprecipitation was then performed to examine whether TUG1 RNA was bound to PRC2, a TUG1-involved regulation mechanism reported in previous studies. The results demonstrated that TUG1 RNA was bound to enhancer of zeste protein 2/embryonic ectoderm development (EZH2/EED), which is essential for PRC2. Finally, our designed ChIP assay revealed that the EZH2/EED was bound to the promotor region of CELF1 within 992 bp upstream of the transcript start site. TUG1 is downregulated in NSCLC. Using TUG1 4C sequencing and bioinformatic analysis, we found CELF1 to be a potential target of TUG1 RNA in in-trans regulation. Moreover, subsequent experiments showed

Downregulation of the long non-coding RNA TUG1 is associated with cell proliferation, migration, and invasion in breast cancer.

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Fan, Shulin; Yang, Zhaoying; Ke, Zirui; Huang, Keke; Liu, Ning; Fang, Xuedong; Wang, Keren

2017-11-01

Recent studies have identified many long non-coding RNAs (lncRNAs) with critical roles in various biological processes including tumorigenesis. Taurine-upregulated gene 1 (TUG1), is an lncRNA recently reported to be involved in the progression of several human cancers. This study aimed to investigate the clinical significance and biological functions of TUG1 in breast cancer. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to measure TUG1 expression in cells from breast cancer cell lines and in 58 matched pairs of breast cancer and normal tissue samples from patients with clinicopathological comparisons. Gain-and loss-of-function experiments were performed in vitro to investigate the biological role of TUG1. TUG1 expression was significantly downregulated in both breast cancer tissues and cell lines compared to controls, and low TUG1 expression was significantly correlated with mutant p53 expression (p=0.037) and lymph node metastasis (p=0.044). In vitro experiments revealed that TUG1 overexpression significantly suppressed cell proliferation by causing cell cycle arrest and inducing apoptosis in breast cancer cells, while TUG1 knockdown caused increased cell growth via promoting cell cycle progression and regulating the expression of cyclinD1 and CDK4. Further functional assays indicated that TUG1 overexpression significantly promoted cell migration and invasion while TUG1 knockdown had the opposite effects. Our findings indicate that the lncRNA TUG1 is a tumor suppressor in breast cancer, and may serve as a novel prognostic biomarker and potential therapeutic target for patients with breast cancer. Copyright © 2017. Published by Elsevier Masson SAS.

Long noncoding RNA TUG1 is a diagnostic factor in lung adenocarcinoma and suppresses apoptosis via epigenetic silencing of BAX.

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Liu, Huan; Zhou, Guizhi; Fu, Xin; Cui, Haiyan; Pu, Guangrui; Xiao, Yao; Sun, Wei; Dong, Xinhua; Zhang, Libin; Cao, Sijia; Li, Guiqin; Wu, Xiaowei; Yang, Xu

2017-11-24

Lung cancer is one of the leading causes of cancer-related mortality, and responds badly to existing treatment. Thus, it is of urgent need to identify novel diagnostic markers and therapeutic targets. Increasing evidences have indicated that long non-coding RNAs (lncRNAs) play an important role in initiation and progression of lung cancer. However, the role of lncRNA Taurine upregulated 1 (TUG1) in lung adenocarcinoma (LAD) progression is not well known. In this study, we determined the diagnostic value of TUG1 in LAD patients, and further uncovered the underlying functional mechanism. Our results showed that TUG1 was significantly upregulated in LAD cells and serum samples. Receiver operator characteristic (ROC) analysis suggested a relatively higher area under the curve (AUC) of TUG1 (0.756) contrast to cyfra21-1 (0.619). In addition, high TUG1 level was associated with enhanced tumor size, degree of differentiation, lymph node metastases, distant metastasis and TNM stage. Cell functional assays showed that knockdown of TUG1 suppressed LAD cell viability and promoted cell apoptosis. We then sought to reveal the underlying regulatory mechanism, and the pro-apoptotic protein BAX was then identified as the downstream target of TUG1. Gain and loss functional assays showed that inhibition of BAX reversed the induced apoptosis by TUG1 knockdown. Finally, RNA immunoprecipitation and Chromatin immunoprecipitation revealed that TUG1 suppressed BAX expression through physically interacting with EZH2. In conclusion, lncRNA TUG1 is a promising diagnostic marker for LAD patients and suppression of TUG1 levels could be a future direction to promote the prognosis of LAD patients.

Correlação entre os testes da caminhada, marcha estacionária e TUG em hipertensas idosas Correlation between the walk, 2-minute step and TUG tests among hypertensive older women

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R Pedrosa

2009-06-01

Full Text Available CONTEXTUALIZAÇÃO: O aumento de doenças crônicas em idosos, principalmente da Hipertensão Arterial Sistêmica, doença intimamente relacionada ao declínio da capacidade funcional, determina a necessidade do estudo de métodos de avaliação da realização das atividades, possibilitando detecção de níveis de capacidade funcional, prescrição de exercícios e acompanhamento das funções cardiovascular e motora. O teste da caminhada de 6 minutos (TC6', o teste da Marcha Estacionária de 2 minutos (TME2' e o teste Timed Up and Go (TUG são indicados para esta avaliação. Estudos em idosos saudáveis mostram a associação entre esses testes, facilitando a avaliação da capacidade funcional. Porém, em hipertensos, não existem estudos que avaliem a relação entre TC6', TME2'e TUG, justificando a realização desta pesquisa. OBJETIVOS: Verificar se existe associação entre endurance aeróbia e a mobilidade funcional em idosas hipertensas. MÉTODOS: Estudo observacional, analítico e transversal, com 32 hipertensas idosas, avaliadas por meio do TC6', TME2' e TUG. RESULTADOS:Houve correlação positiva moderada entre TC6' e TME2', r=0,36 (p=0,04 e correlação negativa moderada entre TC6'e TUG, r=-0,59 (p=0,000 e entre TME2' e TUG, r=-0,66 (p=0,000. CONCLUSÕES: Para hipertensas idosas, o TC6' pode ser substituído pelo TME2', assim como em idosos saudáveis. Quanto à correlação entre os TC6', TME2' e TUG, pode-se concluir que existe uma íntima relação entre resistência cardiovascular e mobilidade funcional; havendo menor resistência cardiovascular, há mobilidade funcional precária e vice-versa.BACKGROUND: The increase in chronic diseases among older adults, especially systemic arterial hypertension, a disease that is closely related to declining functional capacity, has created the need to study methods for activity evaluation in order to detect functional capacity levels, prescribe exercises and monitor motor and

TUG1 mediates methotrexate resistance in colorectal cancer via miR-186/CPEB2 axis.

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Li, Changfeng; Gao, Yongjian; Li, Yongchao; Ding, Dayong

2017-09-16

Colorectal cancer (CRC) is a common malignancy, most of which remain unresponsive to chemotherapy. Methotrexate (MTX) is one of the earliest cytotoxic drugs and serves as an anti-metabolite and anti-folate chemotherapy for various types of cancer. However, MTX resistance prevents its clinical application in cancer therapy. Thereby, overcoming the drug resistance is an alternative strategy to maximize the efficacy of MTX therapies in clinics. Long non-coding RNAs (lncRNAs) have gained widespread attention in recent years. More and more evidences have shown that lncRNAs play regulatory roles in various biological activities and disease progression including drug resistance in cancer cells. Here, we observed lncRNA TUG1 was associated to the MTX resistant in colorectal cancer cells. Firstly, quantitative analysis indicated that TUG1 was significantly increased in tumors which were resistant to MTX treatment. TUG1 knockdown re-sensitized the MTX resistance in colorectal cancer cells, which were MTX-resistant colorectal cell line. Furthermore, bioinformatics analysis showed that miR-186 could directly bind to TUG1, suggesting TUG1 might worked as a ceRNA to sponge miR-186. Extensively, our study also showed that CPEB2 was the direct target of miR-186 in colorectal cancer cells. Taken together, our study suggests that lncRNA TUG1 mediates MTX resistance in colorectal cancer via miR-186/CPEB2 axis. Copyright © 2017. Published by Elsevier Inc.

TUG1 promotes lens epithelial cell apoptosis by regulating miR-421/caspase-3 axis in age-related cataract.

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Li, Guoxing; Song, Huiyang; Chen, Lei; Yang, Weihua; Nan, Kaihui; Lu, Peirong

2017-07-01

Age-related cataract is among the most common chronic disorders of ageing and the apoptosis of lens epithelial cells contributes to non-congenital cataract development. We amid to explore the role of TUG1 and miR-421 in the age-related cataract. The expression level of TUG1, miR-421 and caspase-3 were detected by RT-qPCR. The apoptotic-related protein, caspase-3, Bax and blc-2 were analyzed by western blot. We performed ultraviolet (UV) irradiation to induce SAR01/04 cell apoptosis which was analyzed by flow cytometry. RIP pull-down and luciferase reporter assay were used to verified the combination and regulating among TUG1, miR-421 and caspase-3. Here, we observed that the expression level of TUG1 and caspase-3 in the anterior lens capsules of age-related cataract were significantly higher and miR-421 was significantly lower than that in the normal anterior lens capsules. The apoptosis-related protein, caspase-3, Bax and blc-2 were abnormal expression in the anterior lens capsules of age-related cataract tissue. Our data showed that the expression level of TUG1 and caspase-3 and cell apoptosis rate in SAR01/04 cells treated with UV irradiation was remarkably higher than that in the control. TUG1 negatively regulated miR-421 expression and promoted UV irradiation-induced SAR01/04 cell apoptosis. However, miR-421 inhibitor and pcDNA-caspase-3 could reverse the action of the SRA01/04 cell apoptosis by si-TUG1, which suggested TUG1 promoted UV irradiation-induced apoptosis through downregulating miR-421 expression. Furthermore, this study confirmed TUG1 could been in combination with miR-421, and TUG1 and caspase-3 were both a directly target of miR-421. TUG1 modulated lens epithelial cell apoptosis through miR-421/caspase-3 axis. These findings will offer a novel insight into the pathogenesis of cataract. Copyright © 2017 Elsevier Inc. All rights reserved.

Downregulation of the long noncoding RNA TUG1 inhibits the proliferation, migration, invasion and promotes apoptosis of renal cell carcinoma.

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Zhang, Meng; Lu, Wei; Huang, Yiqiang; Shi, Jizhou; Wu, Xun; Zhang, Xiaolong; Jiang, Runze; Cai, Zhiming; Wu, Song

2016-08-01

Long non-coding RNAs, a newly discovered category of noncoding genes, play a leading role in various biological processes, including tumorigenesis. In our study, we aimed to examine the TUG1 expression, and explore the influence of TUG1 silencing on cell proliferation and apoptosis in renal cell carcinoma (RCC) cell lines. The TUG1 expression level was detected using quantitative real-time PCR reverse transcription-polymerase chain reaction in 40 paired clear cell renal cell carcinoma (ccRCC) and adjacent paired normal tissues, as well as four RCC cell lines and one normal human proximal tubule epithelial cell line HK-2. Small interfering RNA was applied to suppress the TUG1 expression in RCC cell lines (A489 and A704). In vitro assays were conducted to further deliberate its potential functions in RCC progression. The relative TUG1 expression was significantly higher in ccRCC tissues compared to the adjacent normal renal tissues. In addition, higher TUG1 expression was equally detected in RCC cell lines (particularly in A498 and A704) compared to HK-2. The ccRCC specimens with higher TUG1 expression had a higher Fuhrman grade and larger tumor size than those with lower TUG1 expression. In vitro assays results suggested that knockdown of TUG1 suppressed RCC cells migration, invasion and proliferation, while the apoptosis process was activated. Our results indicate that TUG1 is identified as a novel oncogene in the morbid state of RCC, which potentially acts as a therapeutic target/biomarker in RCC. The graphic abstract of the present work.

The long noncoding RNA Tug1 connects metabolic changes with kidney disease in podocytes.

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Li, Szu Yuan; Susztak, Katalin

2016-11-01

An increasing amount of evidence suggests that metabolic alterations play a key role in chronic kidney disease (CKD) pathogenesis. In this issue of the JCI, Long et al. report that the long noncoding RNA (lncRNA) taurine-upregulated 1 (Tug1) contributes to CKD development. The authors show that Tug1 regulates mitochondrial function in podocytes by epigenetic targeting of expression of the transcription factor PPARγ coactivator 1α (PGC-1α, encoded by Ppargc1a). Transgenic overexpression of Tug1 specifically in podocytes ameliorated diabetes-induced CKD in mice. Together, these results highlight an important connection between lncRNA-mediated metabolic alterations in podocytes and kidney disease development.

The long noncoding RNA TUG1 regulates blood-tumor barrier permeability by targeting miR-144.

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Cai, Heng; Xue, Yixue; Wang, Ping; Wang, Zhenhua; Li, Zhen; Hu, Yi; Li, Zhiqing; Shang, Xiuli; Liu, Yunhui

2015-08-14

Blood-tumor barrier (BTB) limits the delivery of chemotherapeutic agent to brain tumor tissues. Long non-coding RNAs (lncRNAs) have been shown to play critical regulatory roles in various biologic processes of tumors. However, the role of lncRNAs in BTB permeability is unclear. LncRNA TUG1 (taurine upregulated gene 1) was highly expressed in glioma vascular endothelial cells from glioma tissues. It also upregulated in glioma co-cultured endothelial cells (GEC) from BTB model in vitro. Knockdown of TUG1 increased BTB permeability, and meanwhile down-regulated the expression of the tight junction proteins ZO-1, occludin, and claudin-5. Both bioinformatics and luciferase reporter assays demonstrated that TUG1 influenced BTB permeability via binding to miR-144. Furthermore, Knockdown of TUG1 also down-regulated Heat shock transcription factor 2 (HSF2), a transcription factor of the heat shock transcription factor family, which was defined as a direct and functional downstream target of miR-144. HSF2 up-regulated the promoter activities and interacted with the promoters of ZO-1, occludin, and claudin-5 in GECs. In conclusion, our results indicate that knockdown of TUG1 increased BTB permeability via binding to miR-144 and then reducing EC tight junction protein expression by targeting HSF2. Thus, TUG1 may represent a useful future therapeutic target for enhancing BTB permeability.

TUG1 promotes osteosarcoma tumorigenesis by upregulating EZH2 expression via miR-144-3p

OpenAIRE

Cao, Jiaqing; Han, Xinyou; Qi, Xin; Jin, Xiangyun; Li, Xiaolin

2017-01-01

lncRNA-TUG1 (Taurine upregulated 1) is up regulated and highly correlated with poor prognosis and disease status in osteosarcoma. TUG1 knockdown inhibits osteosarcoma cell proliferation, migration and invasion, and promotes apoptosis. However, its mechanism of action has not been well addressed. Growing evidence documented that lncRNA works as competing endogenous (ce)RNAs to modulate the expression and biological functions of miRNA. As a putative combining target of TUG1, miR-144-3p has been...

In vitro and mouse in vivo characterization of the potent free fatty acid 1 receptor agonist TUG-469

DEFF Research Database (Denmark)

Urban, C; Hamacher, A; Partke, H J

2013-01-01

in vitro potency of TUG-469 compared to the reference FFA1 agonist GW9508 and to prove in vivo activity in a pre-diabetic mouse model. The in vitro pharmacology of TUG-469 was studied using Ca(2+)-, cAMP-, and impedance-based assays at recombinant FFA1 and free fatty acid receptor 4, formerly known as GPR......120 (FFA4) expressing 1321N1 cells and the rat insulinoma cell line INS-1. Furthermore, we investigated the systemic effect of TUG-469 on glucose tolerance in pre-diabetic New Zealand obese (NZO) mice performing a glucose tolerance test after intraperitoneal administration of 5 mg/kg TUG-469...... significantly improved glucose tolerance in pre-diabetic NZO mice. TUG-469 turned out as a promising candidate for further drug development of FFA1 agonists for treatment of type 2 diabetes mellitus....

Long non-coding RNA TUG1 promotes cell proliferation and metastasis in human breast cancer.

Science.gov (United States)

Li, Teng; Liu, Yun; Xiao, Haifeng; Xu, Guanghui

2017-07-01

Long non-coding RNAs (LncRNAs) utilize a wide variety of mechanisms to regulate RNAs or proteins on the transcriptional or post-transcriptional levels. Accumulating studies have identified numerous LncRNAs to exert critical effects on different physiological processes, genetic disorders, and human diseases. Both clinical tissues from breast cancer patients and cultured cells were used for the qRT-PCR analysis. Specific siRNAs were included to assess the roles of TUG1 with cell viability assay, transwell assay, and cell apoptosis assay, respectively. The expression of TUG1 was enhanced in breast cancerous tissues and in highly invasive breast cancer cell lines and was associated with clinical variables, including tumor size, distant metastasis and TNM staging. Knockdown of TUG1 significantly slowed down cell proliferation, cell migration, and invasion in breast cancer cell lines MDA-MB-231 and MDA-MB-436. In addition, cell apoptotic rate was shown to increase upon siTUG1 treatment as evidenced by increases of the activities of caspase-3 and caspase-9. The identification of TUG1 as a critical mediator of breast cancer progression implied that it might serve as a biomarker for the diagnosis and treatment of breast cancer in clinic.

Upregulation of long non-coding RNA TUG1 promotes bladder cancer cell 5 proliferation, migration and invasion by inhibiting miR-29c.

Science.gov (United States)

Guo, Peng; Zhang, Guohui; Meng, Jialin; He, Qian; Li, Zhihui; Guan, Yawei

2018-01-10

Bladder cancer (BC) is one of the leading causes of cancer-related death in the word. Long non-coding RNA (lncRNA) taurine-upregulated gene 1 (TUG1) plays an important role in the development and progression of numerous cancers, including BC. However, the exact role of TUG1 in modulating BC progression is still poorly known. In this study, we found that TUG1 was upregulated and microRNA-29c (miR-29c) was downregulated in BC tissues and cell lines. Overexpression of TUG1 promoted the cell proliferation of T24 and EJ cells, whereas TUG1 knockdown had the opposite effect. Upregulation of TUG1 obviously facilitated the migration and invasion of T24 and EJ cells. In contrast, TUG1 silencing repressed the migration and invasion of T24 and EJ cells. Furthermore, TUG1 knockdown markedly increased the expression of miR-29c in vitro. On the contrary, overexpression of TUG1 remarkably decreased the expression of miR-29c. Transfection with plasmids containing mutant TUG1 has no effect on the expression of miR-29c. There were direct interactions between miR-29c and the binding sites of TUG1. In addition, the inhibitory effects of small interfering RNA specific for TUG1 on BC cell proliferation, migration and invasion were reversed by downregulation of miR-29c. Collectively, our study strongly demonstrates that TUG1 promotes BC cell proliferation, migration and invasion by inhibiting miR-29c, suggesting that lncRNATUG1 may be a promising target for BC gene therapy.

Knockdown of Long Noncoding RNA TUG1 Inhibits the Proliferation and Cellular Invasion of Osteosarcoma Cells By Sponging MiR-153.

Science.gov (United States)

Wang, Heping; Yu, Yanzhang; Fan, Shuxin; Luo, Leifeng

2017-04-12

Long noncoding RNA (lncRNA) Taurine-upregulated gene 1 (TUG1) has been confirmed to be involved in the progression of various cancers, however, its mechanism of action in osteosarcoma has not been well addressed. In our study, TUG1 was overexpressed and miR-153 was downregulated in osteosarcoma tissues and cell lines. Loss-of-function assay showed that TUG1 knockdown suppressed the viability, colony formation, and invasion of osteosarcoma cells in vitro. Moreover, TUG1 was confirmed to be a miR-153 sponge. Ectopic expression of TUG1 reversed the inhibitory effect of miR-153 on the proliferation and invasion of osteosarcoma cells. Further transplantation experiment proved the carcinogenesis of TUG1 in osteosarcoma in vivo. Collectively, our study elucidated that TUG1 contributed to the osteosarcoma development by sponging miR-153. These findings may provide a novel lncRNA-targeted therapy for patients with osteosarcoma.

LncRNA TUG1 influences papillary thyroid cancer cell proliferation, migration and EMT formation through targeting miR-145.

Science.gov (United States)

Lei, Hongwei; Gao, Yan; Xu, Xiaoying

2017-07-01

LncRNA TUG1, a tumor oncogene associated with various human cancers, has been reported to be involved in regulating various cellular processes, such as proliferation, apoptosis and invasion through targeting multiple genes. However, its biological function in thyroid cancer cells has not been elucidated. The aim of this study is to measure TUG1 expression level and evaluate its function in thyroid cancer cells. LncRNA TUG1 expression levels in thyroid cancer tissues and three thyroid cancer cell lines (the ATC cell lines SW1736 and KAT18 and the FTC cell line FTC133) were assessed by qRT-PCR and compared with that of the human normal breast epithelial cell HGC-27. MTT assay, colony formation assay, transwell assay and western blot analysis were performed to assess the effects of TUG1 on proliferation, metastasis and EMT formation in thyroid cancer cells in vitro. Rescue assay was performed to further confirm that TUG1 contributes to the progression of thyroid cancer cells through regulating miR-145/ZEB1 signal pathway. LncRNA TUG1 was found to be up-regulated in thyroid cancer tissues and thyroid cancer cells compared with that in the human normal breast epithelial cell HGC-27. Increased lncRNA TUG1 expression was found to significantly promote tumor cell proliferation, and facilitate cell invasion, while down-regulated TUG1 could obviously inhibit cell proliferation, migration/invasion and reverse EMT to MET. These results indicated that TUG1 may contribute to the progression of thyroid cancer cells by function as a ceRNA competitive sponging miR-145, and that lncRNA TUG1 is associated with tumor progression in thyroid cancer cells. © The Author 2017. Published by Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The long non-coding RNA TUG1 indicates a poor prognosis for colorectal cancer and promotes metastasis by affecting epithelial-mesenchymal transition.

Science.gov (United States)

Sun, Junfeng; Ding, Chaohui; Yang, Zhen; Liu, Tao; Zhang, Xiefu; Zhao, Chunlin; Wang, Jiaxiang

2016-02-08

Long intergenic non-coding RNAs (lncRNAs) are a class of non-coding RNAs that are involved in gene expression regulation. Taurine up-regulated gene 1 (TUG1) is a cancer progression related lncRNA in some tumor oncogenesis; however, its role in colorectal cancer (CRC) remains unclear. In this study, we determined the expression patterns of TUG1 in CRC patients and explored its effect on CRC cell metastasis using cultured representative CRC cell lines. The expression levels of TUG1 in 120 CRC patients and CRC cells were determined using quantitative real-time PCR. HDACs and epithelial-mesenchymal transition (EMT)-related gene expression were determined using western blot. CRC cell metastasis was assessed by colony formation, migration assay and invasion assay. Our data showed that the levels of TUG1 were upregulated in both CRC cell lines and primary CRC clinical samples. TUG1 upregulation was closely correlated with the survival time of CRC patients. Overexpression of TUG1 in CRC cells increased their colony formation, migration, and invasion in vitro and promoted their metastatic potential in vivo, whereas knockdown of TUG1 inhibited the colony formation, migration, and invasion of CRC cells in vitro. It is also worth pointing out that TUG1 activated EMT-related gene expression. Our data suggest that tumor expression of lncRNA TUG1 plays a critical role in CRC metastasis. TUG1 may have potential roles as a biomarker and/or a therapeutic target in colorectal cancer.

EZH2-mediated α-actin methylation needs lncRNA TUG1, and promotes the cortex cytoskeleton formation in VSMCs.

Science.gov (United States)

Chen, Rong; Kong, Peng; Zhang, Fan; Shu, Ya-Nan; Nie, Xi; Dong, Li-Hua; Lin, Yan-Ling; Xie, Xiao-Li; Zhao, Li-Li; Zhang, Xiang-Jian; Han, Mei

2017-06-15

Recent studies have revealed that long non-coding RNAs (lncRNAs) participate in vascular homeostasis and pathophysiological conditions development. But still very few literatures elucidate the regulatory mechanism of non-coding RNAs in this biological process. Here we identified lncRNA taurine up-regulated gene 1 (TUG1) in rat vascular smooth muscle cells (VSMCs), and got 4612bp nucleotide sequence. The expression level of TUG1 RNA was increased in synthetic VSMCs by real-time PCR analysis. Meanwhile, the expression of enhancer of zeste homolog 2 (EZH2) (TUG1 binding protein) increased in cytoplasm of VSMCs under the same conditions. Immunofluoresce analysis displayed the colocalization of EZH2 with α-actin in cytoplasm and F-actin in cell edge ruffles. This leads us to hypothesize the existence of cytoplasmic TUG1/EZH2/α-actin complex. Using RNA pull down assay, we found that TUG1 interacted with both EZH2 and α-actin. Disruption of TUG1 abolished the interaction of EZH2 with α-actin, and accelerated depolymerization of F-actin in VSMCs. Based on EZH2 methyltransferase activity and the potential methylation sites in α-actin structure, we revealed that α-actin was lysine-methylated. Furthermore, the methylation of α-actin was inhibited by knockdown of TUG1. In conclusion, these findings partly suggested that EZH2-mediated methylation of α-actin may be dependent on TUG1, and thereby promotes cortex F-actin polymerization in synthetic VSMCs. Copyright © 2017. Published by Elsevier B.V.

Long non-coding RNA TUG1 promotes progression of oral squamous cell carcinoma through upregulating FMNL2 by sponging miR-219.

Science.gov (United States)

Yan, Guangqi; Wang, Xue; Yang, Mingliang; Lu, Li; Zhou, Qing

2017-01-01

Oral squamous cell carcinoma (OSCC) is a prevalent oral disease with a high morbidity and mortality rate. Several long non-coding RNAs (lncRNAs) were identified as important regulators of carcinogenesis. However, the pathogenic implications of TUG1 in OSCC are still unclear. In the present study, the expression of TUG1 was increased in OSCC cells. Knockdown of TUG1 inhibited cell proliferation, migration, and invasion, and induced cell cycle arrest at G0/G1 phase, whereas overexpression of TUG1 exerted the opposite effect on OSCC cells. A reciprocal repressive interaction between TUG1 and miR-219 was found, and miR-219 inhibition abolished the tumor-suppressive effect of TUG1 knockdown on cell growth and motility. Furthermore, bioinformatics analysis and luciferase reporter assay showed that FMNL2 was a direct target of miR-219. Restoration of FMNL2 abrogated the miR-219-induced inhibition of cell proliferation, cell cycle progression, migration, and invasion. Besides, overexpression of TUG1 promoted tumor growth and metastasis in vivo . Clinically, the expression of TUG1 and FMNL2 were increased, but miR-219 was decreased in primary tumors compared to non-tumor tissues. Both the upregulated TUG1, and FMNL2 and the downregulated miR-219 was associated with advanced stage of OSCC and poor overall survival. Notably, multivariate analyses confirmed that FMNL2 was an independent risk factor for OSCC. In conclusion, our data revealed that TUG1 confers oncogenic function in OSCC and TUG1/miR-219/FMNL2 axis may be a novel therapeutic strategy in this disease.

LncRNA TUG1 sponges microRNA-9 to promote neurons apoptosis by up-regulated Bcl2l11 under ischemia.

Science.gov (United States)

Chen, Shengcai; Wang, Mengdie; Yang, Hang; Mao, Ling; He, Quanwei; Jin, Huijuan; Ye, Zi-Ming; Luo, Xue-Ying; Xia, Yuan-Peng; Hu, Bo

2017-03-25

Emerging studies have illustrated that LncRNAs TUG1 play critical roles in multiple biologic processes. However, the LncRNA TUG1 expression and function in ischemic stroke have not been reported yet. In this study, we found that LncRNA TUG1 expression was significantly up-regulated in brain ischemic penumbra from rat middle carotid artery occlusion (MCAO) model, while similar results were also observed in cultured neurons under oxygen-glucose deprivation (OGD) insult. Knockdown of TUG1 decreased the ratio of apoptotic cells and promoted cells survival in vitro, which may be regulated by the elevated miRNA-9 expression and decreased Bcl2l11 protein. Furthermore, TUG1 could directly interact with miR-9 and down-regulating miR-9 could efficiently reverse the function of TUG1 on the Bcl2l11 expression. In summary, our result sheds light on the role of LncRNA TUG1 as a miRNA sponge for ischemic stroke, possibly providing a new therapeutic target in stroke. Copyright © 2017 Elsevier Inc. All rights reserved.

Role of LncRNA TUG1 in intervertebral disc degeneration and nucleus pulposus cells via regulating Wnt/β-catenin signaling pathway.

Science.gov (United States)

Chen, Jiang; Jia, Yu-Song; Liu, Gen-Zhe; Sun, Qi; Zhang, Fan; Ma, Sheng; Wang, Yong-Jun

2017-09-23

To investigate the role of TUG1 in intervertebral disc degeneration (IDD) and human nucleus pulposus cells (NPCs) via regulating Wnt/β-catenin pathway. The study collected nucleus pulposus (NP) tissue samples from 30 patients with lumbar disc herniation (LDH) (Case group) and 18 patients with lumbar spine trauma (Control group). NPCs induced by TNF-α in vitro were divided into Blank, Vector, TUG1, TUG1-siRNA, XAV-939, TUG1 + XAV-939 groups. qRT-PCR was used to detect the expression of TUG1 and ECM-related genes, Western blot to determine the expression of Wnt/β-catenin pathway and apoptosis-related proteins, and ELISA to measure the expression of ECM-related proteins. The apoptosis was detected by TUNEL and Annexin V-FITC/PI double-staining. The proliferation and senescence were tested by CCK-8 and SA-β-gal staining respectively. TUG1 was upregulated in patients with IDD, which was positively related to Wnt and β-catenin. Besides, TUG1, Wnt1 and β-catenin were greatly increased in the NPCs after TNF-α induction. Compared with the Blank group, TUG1-siRNA and XAV-939 can appreciably down-regulate the expressions of Wnt1, β-catenin, Caspase-3, Bax, MMP3 and ADAMTS5, up-regulate the expression of Bcl-2, Aggrecan and COL2A1, inhibit the apoptosis and senescence, and promote cell proliferation; however, the TUG1 group had the completely opposite results. Silencing TUG1 may not only protect human NPCs from TNF-α-induced apoptosis and senescence, but also promote cell proliferation by blocking Wnt/β-catenin pathway, which provides a theoretical basis for the clinical treatment of IDD. Copyright © 2017 Elsevier Inc. All rights reserved.

Authentication and consensus overhead in vehicular ad hoc networks

NARCIS (Netherlands)

Petit, Jonathan; Mammeri, Zoubir

Vehicular ad hoc networks aim at increasing passenger safety by exchanging warning messages between vehicles wirelessly. A main challenge is to resist to various malicious abuses and security attacks. However, any security mechanism comes with overhead. We analyze how the authentication algorithm

Accurate 3D Localization Method for Public Safety Applications in Vehicular Ad-hoc Networks

KAUST Repository

Ansari, Abdul Rahim

2018-04-10

Vehicular ad hoc networks (VANETs) represent a very promising research area because of their ever increasing demand, especially for public safety applications. In VANETs vehicles communicate with each other to exchange road maps and traffic information. In many applications, location-based services are the main service, and localization accuracy is the main problem. VANETs also require accurate vehicle location information in real time. To fulfill this requirement, a number of algorithms have been proposed; however, the location accuracy required for public safety applications in VANETs has not been achieved. In this paper, an improved subspace algorithm is proposed for time of arrival (TOA) measurements in VANETs localization. The proposed method gives a closed-form solution and it is robust for large measurement noise, as it is based on the eigen form of a scalar product and dimensionality. Furthermore, we developed the Cramer-Rao Lower Bound (CRLB) to evaluate the performance of the proposed 3D VANETs localization method. The performance of the proposed method was evaluated by comparison with the CRLB and other localization algorithms available in the literature through numerous simulations. Simulation results show that the proposed 3D VANETs localization method is better than the literature methods especially for fewer anchors at road side units and large noise variance.

Long non-codingRNA (lncRNA) TUG1 and the prognosis of cancer: a meta-analysis.

Science.gov (United States)

Yu, X-H; Guo, W; Zhang, J; Ma, C; Chu, A-J; Wen, B-L; Zhang, X; Yan, X-Y; Wu, C-M; Wang, D-M; Qu, Y-L

2017-03-31

Some studies assessed the association between lncRNA taurine-upregulated gene 1 (TUG1) and the survival in cancer. However, the results were inconclusive.  Therefore, we performed a meta-analysis to determine this association. We used the following electronic databases to search for eligible literature: PubMed, Embase, Chinese National Knowledge Infrastructure (CNKI) and Wanfang. We used ORs and 95% CIs to measure the association between TUG1 and the survival of cancer. There was no significant association between TUG1 and OS of cancer (HR=1.26, 95% CI=0.97-1.64). In the subgroup analysis by cancer type, significant association could be find in osteosarcoma (HR=1.72, 95% CI=1.27-2.32) and digestive system's tumors (HR=1.66, 95% CI=1.04-2.66). In conclusion, this meta-analysis study indicated that TUG1 might associate with the OS of osteosarcoma and digestive system's tumors.

LncRNA TUG1 sponges miR-145 to promote cancer progression and regulate glutamine metabolism via Sirt3/GDH axis.

Science.gov (United States)

Zeng, Bing; Ye, Huilin; Chen, Jianming; Cheng, Di; Cai, Canfeng; Chen, Guoxing; Chen, Xiang; Xin, Haiyang; Tang, Chaoming; Zeng, Jun

2017-12-26

Long noncoding RNAs (lncRNAs) are important regulators in cancer progression. Deregulation of the lncRNA taurine upregulated gene 1 (TUG1) predicts poor prognosis and is implicated in the development of several cancers. In this study, we investigated the role of TUG1 in the pathogenesis of intrahepatic cholangiocarcinoma (ICC). We found that TUG1 is upregulated in ICC samples, which correlates with poor prognosis and adverse clinical pathological characteristics. Knockdown of TUG1 inhibited the proliferation, motility, and invasiveness of cultured ICC cells, and decreased tumor burden in a xenograft mouse model. When we explored the mechanisms underlying these effects, we found that TUG1 acts as an endogenous competing RNA (ceRNA) that 'sponges' miR-145, thereby preventing the degradation of Sirt3 mRNA and increasing expression of Sirt3 and GDH proteins. Accordingly, glutamine consumption, α-KG production, and ATP levels were dramatically decreased by TUG1 knockdown in ICC cells, and this effect was reversed by miR-145 inhibition. These findings indicate that the TUG1/miR-145/Sirt3/GDH regulatory network may provide a novel therapeutic strategy for treatment of ICC.

Long non-coding RNA TUG1 promotes cervical cancer progression by regulating the miR-138-5p-SIRT1 axis.

Science.gov (United States)

Zhu, Jie; Shi, Huirong; Liu, Huina; Wang, Xiaojuan; Li, Fengmei

2017-09-12

Increasing evidences showed that long non-coding RNAs (lncRNAs) play vital roles in tumor progression. Recent studies indicated that lncRNA TUG1 was upregulated and promoted tumor processes in several cancers. However, the expression and underlying mechanism of TUG1 in cervical cancer remain unclear. In the present study, we found that TUG1 expression was upregulated in cervical cancer tissues and correlated with advanced clinical features and poor overall survival. TUG1 knockdown suppressed cervical cancer cell growth and metastasis in vitro and tumor growth in vivo . In addition, our results indicated that TUG1 could act as an endogenous sponge by directly binding to miR-138-5p and suppressed miR-138-5p expression. Furthermore, we found that TUG1 could reverse the inhibitory effect of miR-138-5p on cervical cancer cells processes, which might be involved in the activation of SIRT1, a target gene of miR-138-5p, and activation of Wnt/β-catenin signaling pathway. Taken together, we elucidated that TUG1 might promote cervical cancer malignant progression via miR-138-5p-SIRT1-Wnt/β-catenin signaling pathway axis.

Upregulation of the long noncoding RNA TUG1 promotes proliferation and migration of esophageal squamous cell carcinoma.

Science.gov (United States)

Xu, Youtao; Wang, Jie; Qiu, Mantang; Xu, Lei; Li, Ming; Jiang, Feng; Yin, Rong; Xu, Lin

2015-03-01

Esophageal squamous cell carcinoma (ESCC) is one of the prevalent and deadly cancers worldwide, especially in Eastern Asia. The prognosis of ESCC remains poor; thus, it is still necessary to further dissect the underlying mechanisms and explore therapeutic targets of ESCC. Recent studies show that long noncoding RNAs (lncRNAs) have critical roles in diverse biological processes, including tumorigenesis. Some lncRNAs, such as HOTAIR and POU3F3, were reported to play important roles in ESCC. Here, we characterized the expression profile of taurine-upregulated gene 1 (TUG1), a lncRNA recruiting and binding to polycomb repressive complex 2 (PRC2), in ESCC. In a cohort of 62 patients, TUG1 was significantly overexpressed in ESCC tissues compared with paired adjacent normal tissues, and high expression level of TUG1 was associated with family history and upper segment of esophageal cancer (p TUG1 via siRNA inhibited the proliferation and migration of ESCC cells and blocked the progression of cell cycle. Therefore, our study indicates that TUG1 promotes proliferation and migration of ESCC cells and is a potential oncogene of ESCC.

LncRNA, TUG1 regulates the oral squamous cell carcinoma progression possibly via interacting with Wnt/β-catenin signaling.

Science.gov (United States)

Liang, Shuang; Zhang, Songzi; Wang, Peng; Yang, Chao; Shang, Chen; Yang, Jianjun; Wang, Jun

2017-04-15

Oral squamous cell carcinoma (OSCC) is one the most common cancer affecting the head and neck region, and the molecular mechanisms underlying OSCC development is largely unknown. Long non-coding RNAs (lncRNAs) are emerging as key regulators in tumor development. The present study aimed to investigate the role of lncRNA, taurine upregulated gene 1 (TUG1) in OSCC development. The mRNA and protein expression levels were determined by qRT-PCR and western blotting; flow cytometry and ELISA experiments were employed to examine the cell apoptosis; CCK-8 assay, MTT assay, colony formation assay, and cell invasion assay was used to determine cell growth, cell proliferation and cell invasion, respectively. qRT-PCR results showed that TUG1 was up-regulated in both OSCC tissues and cell lines. The high expression level of TUG1 was significantly correlated with TNM stage, lymph node metastasis and tumor grade in OSCC patients. CCK-8 assay, MTT assay, colony formation assay, and cell invasion assay results showed that knock-down of TUG1 by siRNA transfection suppressed cell growth, cell proliferation, and cell invasion in OSCC cell lines (Tca8113 and TSCCA). The cell apoptosis was induced in Tca8113 and TSCCA cells transfected with TUG1 siRNA. In addition, knock-down of TUG1 in Tca8113 and TSCCA cells significantly suppressed the mRNA and protein expression levels of β-catenin, cyclin D1, and c-myc. Wnt/β-catenin pathway activator (LiCl) reversed the TUG1 knock-down effect on cell proliferation, cell invasion and cell apoptosis in Tca8113 and TSCCA cells. In summary, knock-down of TUG1 suppressed cell growth, proliferation and invasion, and also induced apoptosis of OSCC possibly via targeting Wnt/β-catenin signaling. Our data suggest that knock-down of TUG1 may represent a novel therapeutic target for the management of OSCC. Copyright © 2017. Published by Elsevier B.V.

TUG1 knockdown ameliorates atherosclerosis via up-regulating the expression of miR-133a target gene FGF1.

Science.gov (United States)

Zhang, Lei; Cheng, Hailing; Yue, Yuxia; Li, Shuangzhan; Zhang, Daping; He, Ruili

Long non-coding RNAs (lncRNAs) have been revealed to participate in the pathological events associated with atherosclerosis. However, the exact role of lncRNA taurine-up-regulated gene 1 (TUG1) and its possible molecular mechanism in atherosclerosis remain unidentified. High-fat diet (HFD)-treated ApoE -/- mice were used as an in vivo model of atherosclerosis. Ox-LDL-induced macrophages and vascular smooth muscle cells (VSMCs) were employed as cell models of atherosclerosis. qRT-PCR was performed to detect the expression of TUG1 and miR-133a. Serum levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were analyzed by commercially available enzyme kits. Oil red O and hematoxylin and eosin (H&E) staining were conducted to examine atherosclerotic lesion. Luciferase reporter assay combined with RNA immunoprecipitation (RIP) was applied to confirm the interaction between TUG1, miR-133a and FGF1. Cell proliferation ability was determined by Cell Counting Kit-8 (CCK-8) assay and trypan blue dye exclusion test. Cell apoptosis was evaluated with TUNEL assay. Expression and production of inflammatory cytokines was measured with western blot and ELISA analysis. TUG1 expression was up-regulated in HFD-treated ApoE -/- mice, as well as in ox-LDL-induced RAW264.7 and MOVAS cells. TUG1 knockdown inhibited hyperlipidemia, decreased inflammatory response, and attenuated atherosclerotic lesion in HFD-treated ApoE -/- mice. TUG1 could function as a molecular sponge of miR-133a to suppress its expression. TUG1 overexpression accelerated cell growth, improved inflammatory factor expression, and inhibited apoptosis in ox-LDL-stimulated RAW264.7 and MOVAS cells, while this effect was abated after transfection with miR-133 mimic. Moreover, fibroblast growth factor 1 (FGF1) was identified as a direct target of miR-133a. Restored expression of FGF1 overturned the effect of miR-133a on cell

LncRNA TUG1 sponges miR-204-5p to promote osteoblast differentiation through upregulating Runx2 in aortic valve calcification.

Science.gov (United States)

Yu, Cong; Li, Lifu; Xie, Fei; Guo, Shichao; Liu, Fayuan; Dong, Nianguo; Wang, Yongjun

2018-01-01

Emerging evidence indicates that long non-coding RNAs (lncRNAs) play a vital role in cardiovascular physiology and pathology. Although the lncRNA TUG1 is implicated in atherosclerosis, its function in calcific aortic valve disease (CAVD) remains unknown. In this study, we found that TUG1 was highly expressed in human aortic valves and primary valve interstitial cells (VICs). Moreover, TUG1 knockdown induced inhibition of osteoblast differentiation in CAVD both in vitro and in vivo. Mechanistically, silencing of TUG1 increased the expression of miR-204-5p and subsequently inhibited Runx2 expression at the post-transcriptional level. Importantly, TUG1 directly interacted with miR-204-5p and downregulation of miR-204-5p efficiently reversed the suppression of Runx2 induced by TUG1 short hairpin RNA (shRNA). Thus, TUG1 positively regulated the expression of Runx2, through sponging miR-204-5p, and promoted osteogenic differentiation in CAVD. All together, the evidence generated by our study elucidates the role of lncRNA TUG1 as a miRNA sponge in CAVD, and sheds new light on lncRNA-directed diagnostics and therapeutics in CAVD. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions please email: journals.permissions@oup.com.

Up-regulation of Long Non-coding RNA TUG1 in Hibernating Thirteen-lined Ground Squirrels

Directory of Open Access Journals (Sweden)

Jacques J. Frigault

2016-04-01

Full Text Available Mammalian hibernation is associated with multiple physiological, biochemical, and molecular changes that allow animals to endure colder temperatures. We hypothesize that long non-coding RNAs (lncRNAs, a group of non-coding transcripts with diverse functions, are differentially expressed during hibernation. In this study, expression levels of lncRNAs H19 and TUG1 were assessed via qRT-PCR in liver, heart, and skeletal muscle tissues of the hibernating thirteen-lined ground squirrels (Ictidomys tridecemlineatus. TUG1 transcript levels were significantly elevated 1.94-fold in skeletal muscle of hibernating animals when compared with euthermic animals. Furthermore, transcript levels of HSF2 also increased 2.44-fold in the skeletal muscle in hibernating animals. HSF2 encodes a transcription factor that can be negatively regulated by TUG1 levels and that influences heat shock protein expression. Thus, these observations support the differential expression of the TUG1–HSF2 axis during hibernation. To our knowledge, this study provides the first evidence for differential expression of lncRNAs in torpid ground squirrels, adding lncRNAs as another group of transcripts modulated in this mammalian species during hibernation.

Prognostic role of lncRNA TUG1 for cancer outcome: Evidence from 840 cancer patients.

Science.gov (United States)

Liu, Jia; Lin, Jieru; Li, Yingqi; Zhang, Yunyuan; Chen, Xian

2017-07-25

LncRNA TUG1 has been demonstrated to be aberrantly expressed in several types of cancer and maybe serve as a prognostic marker for cancer patients. However, most individual studies have been limited by small sample sizes and controversial results. Therefore, this meta analysis was conducted to analyze available data to delineate the potential clinical application of lncRNA TUG1 on cancer prognosis, lymph node metastasis and tumor progression. Up to February 20, 2017, literature collections were conducted by comprehensive searching electronic databases, including Cochrane Library, PubMed, Embase, BioMed Central, Springer, ScienceDirect, ISI Web of Knowledge, together with three Chinese databases. The hazard ratios (HR) with 95% confidence interval (95% CI) were calculated to assess the strength of the association. Eight studies with a total of 840 cancer patients were included in the present meta analysis. The results indicated that elevated lncRNA TUG1 significantly predicted unfavorable overall survival (OS) (HR = 2.06, 95% CI: 1.23-3.45, P = 0.006), but failed to show incline to lymph node metastasis (HR: 1.16, 95% CI: 0.82-1.62, P = 0.40) and disease progression (III/IV vs. I/II: HR 1.16, 95% CI: 0.74-1.81, P = 0.52). In stratified analyses, a significantly unfavorable OS associated with elevated lncRNA TUG1 was observed in both bladder cancer (HR = 2.98, 95% CI: 1.84-4.83, P TUG1 was an independent prognostic biomarker for unfavorable OS but may not susceptible to lymph node metastasis and tumor progression in cancer patients.

Random intermittent search and the tug-of-war model of motor-driven transport

International Nuclear Information System (INIS)

Newby, Jay; Bressloff, Paul C

2010-01-01

We formulate the 'tug-of-war' model of microtubule cargo transport by multiple molecular motors as an intermittent random search for a hidden target. A motor complex consisting of multiple molecular motors with opposing directional preference is modeled using a discrete Markov process. The motors randomly pull each other off of the microtubule so that the state of the motor complex is determined by the number of bound motors. The tug-of-war model prescribes the state transition rates and corresponding cargo velocities in terms of experimentally measured physical parameters. We add space to the resulting Chapman–Kolmogorov (CK) equation so that we can consider delivery of the cargo to a hidden target at an unknown location along the microtubule track. The target represents some subcellular compartment such as a synapse in a neuron's dendrites, and target delivery is modeled as a simple absorption process. Using a quasi-steady-state (QSS) reduction technique we calculate analytical approximations of the mean first passage time (MFPT) to find the target. We show that there exists an optimal adenosine triphosphate (ATP) concentration that minimizes the MFPT for two different cases: (i) the motor complex is composed of equal numbers of kinesin motors bound to two different microtubules (symmetric tug-of-war model) and (ii) the motor complex is composed of different numbers of kinesin and dynein motors bound to a single microtubule (asymmetric tug-of-war model)

Random intermittent search and the tug-of-war model of motor-driven transport

Science.gov (United States)

Newby, Jay; Bressloff, Paul C.

2010-04-01

We formulate the 'tug-of-war' model of microtubule cargo transport by multiple molecular motors as an intermittent random search for a hidden target. A motor complex consisting of multiple molecular motors with opposing directional preference is modeled using a discrete Markov process. The motors randomly pull each other off of the microtubule so that the state of the motor complex is determined by the number of bound motors. The tug-of-war model prescribes the state transition rates and corresponding cargo velocities in terms of experimentally measured physical parameters. We add space to the resulting Chapman-Kolmogorov (CK) equation so that we can consider delivery of the cargo to a hidden target at an unknown location along the microtubule track. The target represents some subcellular compartment such as a synapse in a neuron's dendrites, and target delivery is modeled as a simple absorption process. Using a quasi-steady-state (QSS) reduction technique we calculate analytical approximations of the mean first passage time (MFPT) to find the target. We show that there exists an optimal adenosine triphosphate (ATP) concentration that minimizes the MFPT for two different cases: (i) the motor complex is composed of equal numbers of kinesin motors bound to two different microtubules (symmetric tug-of-war model) and (ii) the motor complex is composed of different numbers of kinesin and dynein motors bound to a single microtubule (asymmetric tug-of-war model).

Random intermittent search and the tug-of-war model of motor-driven transport

KAUST Repository

Newby, Jay

2010-04-16

We formulate the \\'tug-of-war\\' model of microtubule cargo transport by multiple molecular motors as an intermittent random search for a hidden target. A motor complex consisting of multiple molecular motors with opposing directional preference is modeled using a discrete Markov process. The motors randomly pull each other off of the microtubule so that the state of the motor complex is determined by the number of bound motors. The tug-of-war model prescribes the state transition rates and corresponding cargo velocities in terms of experimentally measured physical parameters. We add space to the resulting Chapman-Kolmogorov (CK) equation so that we can consider delivery of the cargo to a hidden target at an unknown location along the microtubule track. The target represents some subcellular compartment such as a synapse in a neuron\\'s dendrites, and target delivery is modeled as a simple absorption process. Using a quasi-steady-state (QSS) reduction technique we calculate analytical approximations of the mean first passage time (MFPT) to find the target. We show that there exists an optimal adenosine triphosphate (ATP) concentration that minimizes the MFPT for two different cases: (i) the motor complex is composed of equal numbers of kinesin motors bound to two different microtubules (symmetric tug-of-war model) and (ii) the motor complex is composed of different numbers of kinesin and dynein motors bound to a single microtubule (asymmetric tug-of-war model). © 2010 IOP Publishing Ltd.

Random intermittent search and the tug-of-war model of motor-driven transport

KAUST Repository

Newby, Jay; Bressloff, Paul C

2010-01-01

We formulate the 'tug-of-war' model of microtubule cargo transport by multiple molecular motors as an intermittent random search for a hidden target. A motor complex consisting of multiple molecular motors with opposing directional preference is modeled using a discrete Markov process. The motors randomly pull each other off of the microtubule so that the state of the motor complex is determined by the number of bound motors. The tug-of-war model prescribes the state transition rates and corresponding cargo velocities in terms of experimentally measured physical parameters. We add space to the resulting Chapman-Kolmogorov (CK) equation so that we can consider delivery of the cargo to a hidden target at an unknown location along the microtubule track. The target represents some subcellular compartment such as a synapse in a neuron's dendrites, and target delivery is modeled as a simple absorption process. Using a quasi-steady-state (QSS) reduction technique we calculate analytical approximations of the mean first passage time (MFPT) to find the target. We show that there exists an optimal adenosine triphosphate (ATP) concentration that minimizes the MFPT for two different cases: (i) the motor complex is composed of equal numbers of kinesin motors bound to two different microtubules (symmetric tug-of-war model) and (ii) the motor complex is composed of different numbers of kinesin and dynein motors bound to a single microtubule (asymmetric tug-of-war model). © 2010 IOP Publishing Ltd.

Fitness of gutta-percha cones in curved root canals prepared with reciprocating files correlated with tug-back sensation.

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Yoon, Heeyoung; Baek, Seung-Ho; Kum, Kee-Yeon; Kim, Hyeon-Cheol; Moon, Young-Mi; Fang, Denny Y; Lee, WooCheol

2015-01-01

The purpose of this study was to evaluate the gutta-percha-occupied area (GPOA) and the relationship between GPOA and tug-back sensations in canals instrumented with reciprocating files. Twenty curved canals were instrumented using Reciproc R25 (VDW, Munich, Germany) (group R) and WaveOne Primary (Dentsply Maillefer, Ballaigues, Switzerland) (group W), respectively (n = 10 each). The presence or absence of a tug-back sensation was decided for both of #25/.08 and #30/.06 cones in every canal. The percentage of GPOA at 1-, 2-, and 3-mm levels from the working length was calculated using micro-computed tomographic imaging. The correlation between the sum of the GPOA and the presence of a tug-back sensation was also investigated. The data were analyzed statistically at P = .05. A tug-back sensation was present in 45% and 100% canals for #25/.08 and #30/.06 cones, respectively, with a significant difference (P sensation (P .05). Under the conditions of this study, the tug-back sensation can be a definitive determinant for indicating higher cone fitness in the curved canal regardless of the cone type. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Overexpression of long non-coding RNA TUG1 predicts poor prognosis and promotes cancer cell proliferation and migration in high-grade muscle-invasive bladder cancer.

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Iliev, Robert; Kleinova, Renata; Juracek, Jaroslav; Dolezel, Jan; Ozanova, Zuzana; Fedorko, Michal; Pacik, Dalibor; Svoboda, Marek; Stanik, Michal; Slaby, Ondrej

2016-10-01

Long non-coding RNA TUG1 is involved in the development and progression of a variety of tumors. Little is known about TUG1 function in high-grade muscle-invasive bladder cancer (MIBC). The aims of our study were to determine expression levels of long non-coding RNA TUG1 in tumor tissue, to evaluate its relationship with clinico-pathological features of high-grade MIBC, and to describe its function in MIBC cells in vitro. TUG1 expression levels were determined in paired tumor and adjacent non-tumor bladder tissues of 47 patients with high-grade MIBC using real-time PCR. Cell line T-24 and siRNA silencing were used to study the TUG1 function in vitro. We observed significantly increased levels of TUG1 in tumor tissue in comparison to adjacent non-tumor bladder tissue (P TUG1 levels were significantly increased in metastatic tumors (P = 0.0147) and were associated with shorter overall survival of MIBC patients (P = 0.0241). TUG1 silencing in vitro led to 34 % decrease in cancer cell proliferation (P = 0.0004) and 23 % reduction in migration capacity of cancer cells (P TUG1 silencing on cell cycle distribution and number of apoptotic cells. Our study confirmed overexpression of TUG1 in MIBC tumor tissue and described its association with worse overall survival in high-grade MIBC patients. Together with in vitro observations, these data suggest an oncogenic role of TUG1 and its potential usage as biomarker or therapeutic target in MIBC.

Intra-Rater, Inter-Rater and Test-Retest Reliability of an Instrumented Timed Up and Go (iTUG Test in Patients with Parkinson's Disease.

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Rob C van Lummel

Full Text Available The "Timed Up and Go" (TUG is a widely used measure of physical functioning in older people and in neurological populations, including Parkinson's Disease. When using an inertial sensor measurement system (instrumented TUG [iTUG], the individual components of the iTUG and the trunk kinematics can be measured separately, which may provide relevant additional information.The aim of this study was to determine intra-rater, inter-rater and test-retest reliability of the iTUG in patients with Parkinson's Disease.Twenty eight PD patients, aged 50 years or older, were included. For the iTUG the DynaPort Hybrid (McRoberts, The Hague, The Netherlands was worn at the lower back. The device measured acceleration and angular velocity in three directions at a rate of 100 samples/s. Patients performed the iTUG five times on two consecutive days. Repeated measurements by the same rater on the same day were used to calculate intra-rater reliability. Repeated measurements by different raters on the same day were used to calculate intra-rater and inter-rater reliability. Repeated measurements by the same rater on different days were used to calculate test-retest reliability.Nineteen ICC values (15% were ≥ 0.9 which is considered as excellent reliability. Sixty four ICC values (49% were ≥ 0.70 and < 0.90 which is considered as good reliability. Thirty one ICC values (24% were ≥ 0.50 and < 0.70, indicating moderate reliability. Sixteen ICC values (12% were ≥ 0.30 and < 0.50 indicating poor reliability. Two ICT values (2% were < 0.30 indicating very poor reliability.In conclusion, in patients with Parkinson's disease the intra-rater, inter-rater, and test-retest reliability of the individual components of the instrumented TUG (iTUG was excellent to good for total duration and for turning durations, and good to low for the sub durations and for the kinematics of the SiSt and StSi. The results of this fully automated analysis of instrumented TUG movements

Long noncoding RNA TUG1 is downregulated in non-small cell lung cancer and can regulate CELF1 on binding to PRC2

OpenAIRE

Lin, Pei-Chin; Huang, Hsien-Da; Chang, Chun-Chi; Chang, Ya-Sian; Yen, Ju-Chen; Lee, Chien-Chih; Chang, Wen-Hsin; Liu, Ta-Chih; Chang, Jan-Gowth

2016-01-01

Background Long noncoding RNAs (lncRNAs) play crucial roles in tumorigenesis, and lncRNA taurine-upregulated gene 1 (TUG1) has been proven to be associated with several human cancers. However, the mechanisms of TUG1-involved regulation remain largely unknown. Methods We examined the expressions of TUG1 in a cohort of 89 patients with non-small cell lung cancer (NSCLC) to determine the association between TUG1 expression and clinical parameters. We used circular chromosome conformation capture...

Up-regulation of Long Non-coding RNA TUG1 in Hibernating Thirteen-lined Ground Squirrels.

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Frigault, Jacques J; Lang-Ouellette, Daneck; Morin, Pier

2016-04-01

Mammalian hibernation is associated with multiple physiological, biochemical, and molecular changes that allow animals to endure colder temperatures. We hypothesize that long non-coding RNAs (lncRNAs), a group of non-coding transcripts with diverse functions, are differentially expressed during hibernation. In this study, expression levels of lncRNAsH19 and TUG1 were assessed via qRT-PCR in liver, heart, and skeletal muscle tissues of the hibernating thirteen-lined ground squirrels (Ictidomys tridecemlineatus). TUG1 transcript levels were significantly elevated 1.94-fold in skeletal muscle of hibernating animals when compared with euthermic animals. Furthermore, transcript levels of HSF2 also increased 2.44-fold in the skeletal muscle in hibernating animals. HSF2 encodes a transcription factor that can be negatively regulated by TUG1 levels and that influences heat shock protein expression. Thus, these observations support the differential expression of the TUG1-HSF2 axis during hibernation. To our knowledge, this study provides the first evidence for differential expression of lncRNAs in torpid ground squirrels, adding lncRNAs as another group of transcripts modulated in this mammalian species during hibernation. Copyright © 2016 The Authors. Production and hosting by Elsevier Ltd.. All rights reserved.

Effects of siRNA Silencing of TUG1 and LCAL6 Long Non-coding RNAs on Patient-derived Xenograft of Non-small Cell Lung Cancer.

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Fang, Tian; Huang, Hairong; Li, Xiaoyou; Liao, Jing; Yang, Zhijian; Hoffman, Robert M; Cheng, X I; Liang, Lei; Hu, Wenjuan; Yun, Shifeng

2018-01-01

The aim of the present study was to establish a patient-derived xenograft (PDX) mouse model of non-small cell lung cancer (NSCLC) and investigate the anti-tumor efficacy of silencing of TUG1 and LCAL6 long non-coding RNA in the PDX model. PDXs were established by subcutaneously implanting NSCLC surgical tumor fragments into immunodeficient mice. PDX characterization was performed by histopathological, immunohistochemical and real-time polymerase chain reaction (RT-PCR) analyses for NSCLC subtype-specific markers and expression of LCAL6 and TUG1. Anti-tumor efficacy of siRNA silencing of TUG1 and LCAL6 was also investigated in the PDX model. The effect of TUG1 and LCAL6 silencing on protein expression of proliferation marker Ki67 and HOX-gene family HOXB7 in the tumors was assessed by immunohistochemical staining and Western blotting. Establishment of NSCLC PDX models resulted in 9 of 26 cases (34.6%). Lung squamous cell carcinomas (SCC) had a higher engraftment rate (58.3%) than lung adenocarcinomas (ADC) (18.2%) (pTUG1. The tumor volume and weight were significantly reduced in the TUG1-silenced group as compared to the control group (p0.05). Expression of both TUG1and LCAL6 was reduced by siRNA treatment. Expression of Ki67 and HOXB7 was significantly suppressed in both the TUG1- and LCAL6-silenced groups compared to the control group (pTUG1-silenced group showed more reduced Ki67 expression than the LCAL6-silenced group (pTUG1 and LCAL6. Silencing of TUG1 inhibited both tumor growth and expression of the proliferation marker Ki67 and HOX-gene family HOXB7 in the PDX model of NSCLC. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Overexpression of the long noncoding RNA TUG1 protects against cold-induced injury of mouse livers by inhibiting apoptosis and inflammation.

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Su, Song; Liu, Jiang; He, Kai; Zhang, Mengyu; Feng, Chunhong; Peng, Fangyi; Li, Bo; Xia, Xianming

2016-04-01

Hepatic injury provoked by cold storage is a major problem affecting liver transplantation, as exposure to cold induces apoptosis in hepatic tissues. Long noncoding RNAs (lncRNAs) are increasingly understood to regulate apoptosis, but the contribution of lncRNAs to cold-induced liver injury remains unknown. Using RNA-seq, we determined the differential lncRNA expression profile in mouse livers after cold storage and found that expression of the lncRNA TUG1 was significantly down-regulated. Overexpression of TUG1 attenuated cold-induced apoptosis in mouse hepatocytes and liver sinusoidal endothelial cells LSECs, in part by blocking mitochondrial apoptosis and endoplasmic reticulum (ER) stress pathways. Moreover, TUG1 attenuated apoptosis, inflammation, and oxidative stress in vivo in livers subjected to cold storage. Overexpression of TUG1 also improved hepatocyte function and prolonged hepatic graft survival rates in mice. These results suggest that the lncRNA TUG1 exerts a protective effect against cold-induced liver damage by inhibiting apoptosis in mice, and suggests a potential role for TUG1 as a target for the prevention of cold-induced liver damage in liver transplantation. RNA-seq data are available from GEO using accession number GSE76609. © 2016 Federation of European Biochemical Societies.

Increased expression of long noncoding RNA TUG1 predicts a poor prognosis of gastric cancer and regulates cell proliferation by epigenetically silencing of p57.

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Zhang, E; He, X; Yin, D; Han, L; Qiu, M; Xu, T; Xia, R; Xu, L; Yin, R; De, W

2016-02-25

Recent evidence highlights long noncoding RNAs (lncRNAs) as crucial regulators of cancer biology that contribute to tumorigenesis. LncRNA TUG1 was initially detected in a genomic screen for genes upregulated in response to taurine treatment in developing mouse retinal cells. Our previous study showed that TUG1 could affect cell proliferation through epigenetically regulating HOXB7 in human non-small cell lung cancer. However, the clinical significance and potential role of TUG1 in GC remains unclear. In this study, we found that TUG1 is significantly increased and is correlated with outcomes in gastric cancer (GC). Further experiments revealed that knockdown of TUG1 repressed GC proliferation both in vitro and in vivo. Mechanistic investigations showed that TUG1 has a key role in G0/G1 arrest. We further demonstrated that TUG1 was associated with PRC2 and that this association was required for epigenetic repression of cyclin-dependent protein kinase inhibitors, including p15, p16, p21, p27 and p57, thus contributing to the regulation of GC cell cycle and proliferation. Together, our results suggest that TUG1, as a regulator of proliferation, may serve as a candidate prognostic biomarker and target for new therapies in human GC.

The long noncoding RNA TUG1 acts as a competing endogenous RNA to regulate the Hedgehog pathway by targeting miR-132 in hepatocellular carcinoma.

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Li, Jingjing; Zhang, Qinghui; Fan, Xiaoming; Mo, Wenhui; Dai, Weiqi; Feng, Jiao; Wu, Liwei; Liu, Tong; Li, Sainan; Xu, Shizan; Wang, Wenwen; Lu, Xiya; Yu, Qiang; Chen, Kan; Xia, Yujing; Lu, Jie; Zhou, Yingqun; Xu, Ling; Guo, Chuanyong

2017-09-12

Emerging evidence shows that the Hedgehog pathway and the long noncoding RNA TUG1 play pivotal roles in cell proliferation, migration, and invasion in tumors. However, the mechanism underlying the effect of TUG1 and the Hedgehog pathway in hepatoma remains undefined. In the present study, we showed that the expression of TUG1 was negatively correlated with that of microRNA (miR)-132, and depletion of TUG1 inhibited the activation of the Hedgehog pathway in vitro and in vivo . We showed that TUG1 functions as a competing endogenous (ceRNA) by competing with miR-132 for binding to the sonic hedgehog protein in HCC, thereby suppressing the activation of Hedgehog signaling and its tumorigenic effect. These data indicate that targeting the TUG1-miR132-Hedgehog network could be a new strategy for the treatment of HCC.

Long noncoding RNA TUG1 facilitates osteogenic differentiation of periodontal ligament stem cells via interacting with Lin28A.

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He, Qin; Yang, Shuangyan; Gu, Xiuge; Li, Mengying; Wang, Chunling; Wei, Fulan

2018-04-19

Periodontal ligament stem cells (PDLSCs) are mesenchymal stem cells derived from dental tissues with multidirectional differentiation potential and excellent self-renewing ability. Recently, long noncoding RNAs (lncRNAs) have been shown to play important roles in MSC osteogenic differentiation. In this study, we found that taurine upregulated gene 1 (TUG1), an evolutionarily conserved and widely present lncRNA was significantly upregulated in osteogenically induced PDLSCs compared to their undifferentiated counterparts. Further investigation demonstrated that the expression of TUG1 was positively correlated with the osteogenic differentiation of PDLSCs following the induction, as evidenced by the increase in cellular alkaline phosphatase (ALP) level, formation of calcium nodules, and the upregulation of several osteogenic-related gene markers such as ALP, osteocalcin (OCN), and runt-related transcription factor 2 (Runx2). Conversely, TUG1 knockdown was demonstrated to inhibit the potential of PDLSCs for osteogenic differentiation. Using bioinformatics analysis, we identified lin-28 homolog A (Lin28A) as a potential target of TUG1 during osteogenic differentiation of PDLSCs. Lin28A was found to be significantly downregulated in TUG1-repressed PDLSCs and contained multiple binding sites for lncRNA TUG1. Moreover, suppression of Lin28A was shown to be able to inhibit osteogenic differentiation and decreased the expression of several osteogenic genes. Taken together, these results could help researchers better understand the mechanism that governs the osteogenic differentiation of PDLSCs, and also serve as a stepping stone for the development of novel therapeutic strategies that can be used to regenerate dental tissues.

Long non-coding RNA TUG1 is involved in cell growth and chemoresistance of small cell lung cancer by regulating LIMK2b via EZH2.

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Niu, Yuchun; Ma, Feng; Huang, Weimei; Fang, Shun; Li, Man; Wei, Ting; Guo, Linlang

2017-01-09

Taurine upregulated gene1 (TUG1) as a 7.1-kb lncRNA, has been shown to play an oncogenic role in various cancers. However, the biological functions of lncRNA TUG1 in small cell lung cancer (SCLC) remain unknown. The aim of this study is to explore the roles of TUG1 in cell growth and chemoresistance of SCLC and its possible molecular mechanism. The expression of TUG1 in thirty-three cases of SCLC tissues and SCLC cell line were examined by quantitative RT-PCR (qRT-PCR). The functional roles of TUG1 in SCLC were demonstrated by CCK8 assay, colony formation assay, wound healing assay and transwell assay, flow cytometry analysis and in vivo study through siRNA or shRNA mediated knockdown. Western blot assays were used to evaluate gene and protein expression in cell lines. Chromatin immunoprecipitation (ChIP) and RNA binding protein immunoprecipitation (RIP) were performed to confirm the molecular mechanism of TUG1 involved in cell growth and chemoresistance of small cell lung cancer. We found that TUG1 was overexpressed in SCLC tissues, and its expression was correlated with the clinical stage and the shorter survival time of SCLC patients. Moreover, downregulation of TUG1 expression could impair cell proliferation and increased cell sensitivity to anticancer drugs both in vitro and in vivo. We also discovered that TUG1 knockdown significantly promoted cell apoptosis and cell cycle arrest, and inhibited cell migration and invasion in vitro . We further demonstrated that TUG1 can regulate the expression of LIMK2b (a splice variant of LIM-kinase 2) via binding with enhancer of zeste homolog 2 (EZH2), and then promoted cell growth and chemoresistance of SCLC. Together, these results suggested that TUG1 mediates cell growth and chemoresistance of SCLC by regulating LIMK2b via EZH2.

The prognostic potential and carcinogenesis of long non-coding RNA TUG1 in human cholangiocarcinoma

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Xu, Yi; Leng, Kaiming; Li, Zhenglong; Zhang, Fumin; Zhong, Xiangyu; Kang, Pengcheng; Jiang, Xingming; Cui, Yunfu

2017-01-01

Cholangiocarcinoma (CCA) is a fatal disease with increasing worldwide incidence and is characterized by poor prognosis due to its poor response to conventional chemotherapy or radiotherapy. Long non-coding RNAs (lncRNAs) play key roles in multiple human cancers, including CCA. Cancer progression related lncRNA taurine-up-regulated gene 1 (TUG1) was reported to be involved in human carcinomas. However, the impact of TUG1 in CCA is unclear. The aim of this study was to explore the expression pa...

Long non-coding RNA TUG1 is up-regulated in hepatocellular carcinoma and promotes cell growth and apoptosis by epigenetically silencing of KLF2.

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Huang, Ming-De; Chen, Wen-Ming; Qi, Fu-Zhen; Sun, Ming; Xu, Tong-Peng; Ma, Pei; Shu, Yong-Qian

2015-09-04

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide, and the biology of this cancer remains poorly understood. Recent evidence indicates that long non-coding RNAs (lncRNAs) are found to be dysregulated in a variety of cancers, including HCC. Taurine Up-regulated Gene 1 (TUG1), a 7.1-kb lncRNA, recruiting and binding to polycomb repressive complex 2 (PRC2), is found to be disregulated in non-small cell lung carcinoma (NSCLC) and esophageal squamous cell carcinoma (ESCC). However, its clinical significance and potential role in HCC remain unclear. In this study, expression of TUG1 was analyzed in 77 HCC tissues and matched normal tissues by using quantitative polymerase chain reaction (qPCR). TUG1 expression was up-regulated in HCC tissues and the higher expression of TUG1 was significantly correlated with tumor size and Barcelona Clinic Liver Cancer (BCLC) stage. Moreover, silencing of TUG1 expression inhibited HCC cell proliferation, colony formation, tumorigenicity and induced apoptosis in HCC cell lines. We also found that TUG1 overexpression was induced by nuclear transcription factor SP1 and TUG1 could epigeneticly repress Kruppel-like factor 2 (KLF2) transcription in HCC cells by binding with PRC2 and recruiting it to KLF2 promoter region. Our results suggest that lncRNA TUG1, as a growth regulator, may serve as a new diagnostic biomarker and therapy target for HCC.

Double-negative feedback loop between long non-coding RNA TUG1 and miR-145 promotes epithelial to mesenchymal transition and radioresistance in human bladder cancer cells.

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Tan, Jiemei; Qiu, Kaifeng; Li, Mingyi; Liang, Ying

2015-10-07

LncRNAs have a critical role in the regulation of cellular processes such as cancer progression and metastasis. In the present study, we confirmed that TUG1 was overexpressed in bladder cancer tissues and established cell lines. Knockdown of TUG1 inhibited bladder cancer cell metastasis both in vitro and in vivo. Furthermore, we found that TUG1 promoted cancer cell invasion and radioresistance through inducing epithelial-to-mesenchymal transition (EMT). Interestingly, TUG1 decreased the expression of miR-145 and there was a reciprocal repression between TUG1 and miR-145 in an Argonaute2-dependent manner. ZEB2 was identified as a down-stream target of miR-145 and TUG1 exerted its function through the miR-145/ZEB2 axis. In summary, our data indicated that blocking TUG1 function may be an effective anti-cancer therapy. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Inhibition of long non-coding RNA TUG1 on gastric cancer cell transference and invasion through regulating and controlling the expression of miR-144/c-Met axis.

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Ji, Ting-Ting; Huang, Xuan; Jin, Jie; Pan, Sheng-Hua; Zhuge, Xiao-Ju

2016-05-01

To discuss the expression of long noncoding RNA TUG1 (lncRNA-TUG1) in gastric carcinoma (GC) and its effects on the transferring and invading capacity of gastric carcinoma cells. Forty cases of carcinoma tissue and para-carcinoma tissue were selected from GC patients who underwent surgical removal in Zhejiang Provincial Hospital of Chinese Traditional Medicine and Wenzhou Central Hospital from January, 2013 to December, 2014; the expressing level of lncRNA-TUG1 in GC and para-C tissues was detected by applying the qRT-PCR technique. The correlation between lncRNA-TUG1 expression and patients' clinical data was classified and analyzed. SGC-7901 cells were transfected using lncRNA-TUG1 specific siRNA. Changes of the transferring and invading capacity of siRNA-transfected SGC-7901 cells were scratch-tested and transwell-detected. qRT-PCR was applied to detect the expression level of microRNA-144 after lncRNA-TUG1 was silenced. Changes of c-Met mRNA and protein expressions was detected by qRT-PCR and western-blot test. The expression level of lncRNA-TUG1 in GC tissue was significant higher than that in para-C tissue (P TUG1 in GC tissue was significantly correlated with tumor lymph nodes metastasis and advance TNM phasing (P TUG1 specific siRNA (P TUG1 was silenced (P TUG1 shows an up-regulated expression in GC tissue and that bears a correlation with clinicopathological features of malignant tumor. lncRNA-TUG1 can promote the transferring and invading capacity of GC by inhibiting the pathway of microRNA-144/c-Met. Copyright © 2016 Hainan Medical College. Production and hosting by Elsevier B.V. All rights reserved.

Long non-coding RNA TUG1 promotes migration and invasion by acting as a ceRNA of miR-335-5p in osteosarcoma cells.

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Wang, Yong; Yang, Tao; Zhang, Zhen; Lu, Ming; Zhao, Wei; Zeng, Xiandong; Zhang, Weiguo

2017-05-01

Long non-coding RNA (lncRNA) have been the focus of increasing attention due to the role they play in many diseases, including osteosarcoma. The function of taurine upregulated gene 1 (TUG1) and its mechanism in osteosarcoma remain unclear. In our research, we found that TUG1 was elevated and correlated with a poor prognosis in osteosarcoma patients. In addition, the following functional experiment showed that decreased TUG1 could remarkably inhibit osteosarcoma cell migration and invasion, indicating that TUG1 functioned as an oncogene in osteosarcoma. Moreover, we revealed that TUG1 and Rho-associated coiled-coil-containing protein kinase 1 (ROCK1), a metastasis-related gene targeted by microRNA-335-5p (miR-335-5p), had the same miR-335-5p combining site. The subsequent luciferase assay verified TUG1 was a target of miR-335-5p. Furthermore, the results of a real-time quantitative PCR showed that TUG1 and miR-335-5p could affect each other's expression. respectively. Finally, we affirmed that TUG1 affected ROCK1 expression and ROCK1-mediated migration/invasion by working as a competitive endogenous RNA (ceRNA) via miR-335-5p. In summary, the findings of this study, based on ceRNA theory, combining the research foundation of miR-335-5p and ROCK1, and taking TUG1 as a new study point, provide new insight into molecular-level reversing migration and invasion of osteosarcoma. © 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Long Non-Coding RNA TUG1 Promotes Proliferation and Inhibits Apoptosis of Osteosarcoma Cells by Sponging miR-132-3p and Upregulating SOX4 Expression.

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Li, Gang; Liu, Keyu; Du, Xinhui

2018-03-01

Long non-coding RNA taurine upregulated gene 1 (TUG1) is reported to be a vital regulator of the progression of various cancers. This study aimed to explore the exact roles and molecular mechanisms of TUG1 in osteosarcoma (OS) development. Real-time quantitative PCR was applied to detect the expressions of TUG1 and microRNA-132-3p (miR-132-3p) in OS tissues and cells. Western blot was performed to measure protein levels of sex determining region Y-box 4 (SOX4). Cell viability was assessed using XTT assay. Cell apoptosis was evaluated using flow cytometry and caspase-3 activity detection assays. Bioinformatics analysis and luciferase reporter experiments were employed to confirm relationships among TUG1, miR-132-3p, and SOX4. TUG1 was highly expressed in human OS tissues, OS cell lines, and primary OS cells. TUG1 knockdown hindered proliferation and induced apoptosis in human OS cell lines and primary OS cells. Moreover, TUG1 inhibited miR-132-3p expression by direct interaction, and introduction of miR-132-3p inhibitor partly abrogated the effect of TUG1 knockdown on the proliferation and apoptosis of OS cells. Furthermore, SOX4 was validated as a target of miR-132-3p. Further functional analyses revealed that miR-132-3p inhibited proliferation and induced apoptosis of OS cells, while this effect was greatly abated following SOX4 overexpression. Moreover, TUG1 knockdown suppressed proliferation and promoted apoptosis by upregulating miR-132-3p and downregulating SOX4 in primary OS cells. TUG1 facilitated proliferation and suppressed apoptosis by regulating the miR-132-3p/SOX4 axis in human OS cell lines and primary OS cells. This finding provides a potential target for OS therapy. © Copyright: Yonsei University College of Medicine 2018

Screening of long non-coding RNA and TUG1 inhibits proliferation with TGF-β induction in patients with COPD.

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Tang, Wenxiang; Shen, Zhenyu; Guo, Jiang; Sun, Shenghua

2016-01-01

To evaluate differentially expressed long noncoding RNAs (lncRNAs) and the potential role of lncRNA TUG1 in patients with chronic obstructive pulmonary disease (COPD). Total RNA was extracted from both COPD and non-COPD lung tissues, and microarray analysis was performed with 25,628 lncRNA probes and 20,106 mRNA probes. In addition, five up-regulated and five down-regulated lncRNAs were selected for identification using quantitative real-time polymerase chain reaction. COPD cell model was established by transforming growth factor β (TGF-β) treatment. Cell Counting Kit-8 assay was used to detect BEAS-2B and HFL1 cell proliferation after TUG-siRNA transfection with TGF-β treatment. In addition, the expression levels of α-SMA and fibronectin proteins were determined using Western blot in BEAS-2B and HFL1 cells after TUG-siRNA transfection with TGF-β treatment. There were 8,376 (32.7%) differentially expressed lncRNAs and 5,094 (25.3%) differentially expressed mRNAs in COPD lung tissues compared with non-COPD lung tissues. Five of the analyzed lncRNAs (BC038205, BC130595, TUG1, MEG3, and LOC646329) were markedly increased, while five lncRNAs (LOC729178, PLAC2, LOC339529, LINC00229, and SNHG5) were significantly decreased in COPD lung tissues compared with non-COPD lung tissues (n=20) ( ***P TUG1 promotes BEAS-2B and HFL1 cell proliferation after TGF-β treatment through inhibiting the expression levels of α-SMA and fibronectin. Abundant, differentially expressed lncRNAs and mRNAs were identified by microarray analysis and these might play a partial or key role in the diagnosis of patients with COPD. LncRNA TUG1 may become a very important class of biomarker and may act as a potential diagnostic and therapeutic target for patients with COPD.

Long non-coding RNA TUG1 promotes progression of oral squamous cell carcinoma through upregulating FMNL2 by sponging miR-219

OpenAIRE

Yan, Guangqi; Wang, Xue; Yang, Mingliang; Lu, Li; Zhou, Qing

2017-01-01

Oral squamous cell carcinoma (OSCC) is a prevalent oral disease with a high morbidity and mortality rate. Several long non-coding RNAs (lncRNAs) were identified as important regulators of carcinogenesis. However, the pathogenic implications of TUG1 in OSCC are still unclear. In the present study, the expression of TUG1 was increased in OSCC cells. Knockdown of TUG1 inhibited cell proliferation, migration, and invasion, and induced cell cycle arrest at G0/G1 phase, whereas overexpression of TU...

Studies on urban vehicular ad-hoc networks

CERN Document Server

Zhu, Hongzi

2013-01-01

With the advancement of wireless technology, vehicular ad hoc networks (VANETs) are emerging as a promising approach to realizing 'smart cities' and addressing many important transportation problems such as road safety, efficiency, and convenience.This brief provides an introduction to the large trace data set collected from thousands of taxis and buses in Shanghai, the largest metropolis in China. It also presents the challenges, design issues, performance modeling and evaluation of a wide spectrum of VANET research topics, ranging from realistic vehicular mobility models and opportunistic ro

Long non-coding RNA TUG1 contributes to tumorigenesis of human osteosarcoma by sponging miR-9-5p and regulating POU2F1 expression.

Science.gov (United States)

Xie, Chu-Hai; Cao, Yan-Ming; Huang, Yan; Shi, Qun-Wei; Guo, Jian-Hong; Fan, Zi-Wen; Li, Ju-Gen; Chen, Bin-Wei; Wu, Bo-Yi

2016-11-01

Recent studies have shown that long non-coding RNAs (lncRNAs) have critical roles in tumorigenesis, including osteosarcoma. The lncRNA taurine-upregulated gene 1 (TUG1) was reported to be involved in the progression of osteosarcoma. Here, we investigated the role of TUG1 in osteosarcoma cells and the underlying mechanism. TUG1 expression was measured in osteosarcoma cell lines and human normal osteoblast cells by quantitative real-time PCR (qRT-PCR). The effects of TUG1 on osteosarcoma cells were studied by RNA interference in vitro and in vivo. The mechanism of competing endogenous RNA (ceRNA) was determined using bioinformatic analysis and luciferase assays. Our data showed that TUG1 knockdown inhibited cell proliferation and colony formation, and induced G0/G1 cell cycle arrest and apoptosis in vitro, and suppressed tumor growth in vivo. Besides, we found that TUG1 acted as an endogenous sponge to directly bind to miR-9-5p and downregulated miR-9-5p expression. Moreover, TUG1 overturned the effect of miR-9-5p on the proliferation, colony formation, cell cycle arrest, and apoptosis in osteosarcoma cells, which involved the derepression of POU class 2 homeobox 1 (POU2F1) expression. In conclusion, our study elucidated a novel TUG1/miR-9-5p/POU2F1 pathway, in which TUG1 acted as a ceRNA by sponging miR-9-5p, leading to downregulation of POU2F1 and facilitating the tumorigenesis of osteosarcoma. These findings may contribute to the lncRNA-targeted therapy for human osteosarcoma.

Long non-coding RNA TUG1 promotes endometrial cancer development via inhibiting miR-299 and miR-34a-5p.

Science.gov (United States)

Liu, Lifen; Chen, Xin; Zhang, Ying; Hu, Yanrong; Shen, Xiaoqing; Zhu, Weipei

2017-05-09

It is generally known that the human genome makes a large amount of noncoding RNAs compared with coding genes. Long non-coding RNAs (lncRNAs) which composed of more than 200 nucleotides have been described as the largest subclass of the non-coding transcriptome in human noncoding RNAs. Existing research shows that lncRNAs exerted biological functions in various tumors via participating in both oncogenic and tumor suppressing pathways. The previous studies indicated that lncRNA taurine upregulated 1 (TUG1) play important roles in the initiation and progression of malignancies. In this study,based on previous research, we investigated the expression and biological role of the lncRNA-TUG1. We analyzed the relationship between lncRNA-TUG1and endometrial carcinoma (EC) in a total 104 EC carcinoma specimens, compared with that in normal tissues. We found that lncRNA-TUG1 expression in cancer tissues was significantly higher than that in adjacent tissues. Through a series of experiments, the results demonstrated that lncRNA-TUG1 enhances the evolution and progression of EC through inhibiting miR-299 and miR-34a-5p.

Ad-hoc networking towards seamless communications

CERN Document Server

Gavrilovska, Liljana

2006-01-01

Ad-Hoc Networking Towards Seamless Communications is dedicated to an area that attracts growing interest in academia and industry and concentrates on wireless ad hoc networking paradigm. The persistent efforts to acquire the ability to establish dynamic wireless connections from anywhere to anyone with any device without prerequisite imbedded infrastructure move the communications boundaries towards ad-hoc networks. Recently, ad hoc networking has attracted growing interest due to advances in wireless communications, and developed framework for running IP based protocols. The expected degree of penetration of these networks will depend on the successful resolution of the key features. Ad-hoc networks pose many complex and open problems for researchers. Ad-Hoc Networking Towards Seamless Communications reveals the state-of-the-art in wireless ad-hoc networking and discusses some of the key research topics that are expected to promote and accelerate the commercial applications of these networks (e.g., MAC, rout...

LncRNA TUG1 serves an important role in hypoxia-induced myocardial cell injury by regulating the miR-145-5p-Binp3 axis

Science.gov (United States)

Wu, Zhongwei; Zhao, Shengji; Li, Chunfu; Liu, Chaoquan

2018-01-01

The aim of the present study was to investigate the function of long non-coding RNA TUG1 in hypoxia-induced myocardial cell injury and to explore the potential molecular mechanisms. The cardiomyocyte cell line H9c2 was cultured under hypoxic and normoxic conditions. TUG1 expression under hypoxic conditions was then detected. The effects of TUG1 overexpression on viability, apoptosis, migration and invasion were assayed. In addition, the microRNA (miR)-145-5p expression was detected. Following H9c2 cell transfection with miR-145-5p mimics, the H9c2 cell viability, apoptosis, migration and invasion were also detected. Additionally, the target gene of miR-145-5p was assayed by Luciferase reporter assay. The protein expressions of Wnt-3a, Wnt5a, and β-catenin in H9c2 cells under hypoxic conditions were also determined. The results revealed that hypoxia induced injury in H9c2 cells, including inhibiting cell viability, migration and invasion, and promoting cell apoptosis. Overexpression of TUG1 aggravated hypoxia-induced injury in H9c2 cells. In addition, miR-145-5p was negatively regulated by TUG1, and TUG1 overexpression aggravated hypoxia-induced injury via the downregulation of miR-145-5p. Furthermore, B-cell lymphoma 2 interacting protein 3 (Bnip3) was a target of miR-145-5p, and overexpression of Bnip3 aggravated hypoxia-induced cell injury by activating Wnt/β-catenin signaling pathways in H9c2 cells. In conclusion, overexpression of TUG1 aggravated hypoxia-induced injury in cardiomyocytes by regulating the miR-145-5p-Binp3 axis. Activation of the Wnt/β-catenin signaling pathway may be a key mechanism to mediate the role of TUG1 in regulating hypoxia-induced myocardial injury. TUG1 may be an effective diagnostic marker and therapeutic target for myocardial ischemia. PMID:29207102

Down-regulation of LncRNA TUG1 enhances radiosensitivity in bladder cancer via suppressing HMGB1 expression

OpenAIRE

Jiang, Huijuan; Hu, Xigang; Zhang, Hongzhi; Li, Wenbo

2017-01-01

Background Long non-coding RNAs (lncRNAs) have been reported to regulate the sensitivity of different cancer cells to chemoradiotherapy. Aberrant expression of lncRNA Taurine-upregulated gene 1 (TUG1) has been found to be involved in the development of bladder cancer, however, its function and underlying mechanism in the radioresistance of bladder cancer remains unclear. Methods Quantitative real-time PCR (qRT-PCR) was conducted to measure the expression of TUG1 and HMGB1 mRNA in bladder canc...

Screening of long non-coding RNA and TUG1 inhibits proliferation with TGF-β induction in patients with COPD

Directory of Open Access Journals (Sweden)

Tang WX

2016-11-01

Full Text Available Wenxiang Tang,1 Zhenyu Shen,2 Jiang Guo,2 Shenghua Sun1 1Department of Respiratory Medicine, The Third Xiangya Hospital of Central South University, 2Department of Respiratory Medicine, Xiangtan Central Hospital, Hunan, People’s Republic of China Objective: To evaluate differentially expressed long noncoding RNAs (lncRNAs and the potential role of lncRNA TUG1 in patients with chronic obstructive pulmonary disease (COPD.Methods: Total RNA was extracted from both COPD and non-COPD lung tissues, and microarray analysis was performed with 25,628 lncRNA probes and 20,106 mRNA probes. In addition, five up-regulated and five down-regulated lncRNAs were selected for identification using quantitative real-time polymerase chain reaction. COPD cell model was established by transforming growth factor β (TGF-β treatment. Cell Counting Kit-8 assay was used to detect BEAS-2B and HFL1 cell proliferation after TUG-siRNA transfection with TGF-β treatment. In addition, the expression levels of α-SMA and fibronectin proteins were determined using Western blot in BEAS-2B and HFL1 cells after TUG-siRNA transfection with TGF-β treatment.Results: There were 8,376 (32.7% differentially expressed lncRNAs and 5,094 (25.3% differentially expressed mRNAs in COPD lung tissues compared with non-COPD lung tissues. Five of the analyzed lncRNAs (BC038205, BC130595, TUG1, MEG3, and LOC646329 were markedly increased, while five lncRNAs (LOC729178, PLAC2, LOC339529, LINC00229, and SNHG5 were significantly decreased in COPD lung tissues compared with non-COPD lung tissues (n=20 (***P<0.001. Knockdown of lncRNA TUG1 promotes BEAS-2B and HFL1 cell proliferation after TGF-β treatment through inhibiting the expression levels of α-SMA and fibronectin.Conclusion: Abundant, differentially expressed lncRNAs and mRNAs were identified by microarray analysis and these might play a partial or key role in the diagnosis of patients with COPD. LncRNA TUG1 may become a very important

LncRNA TUG1 serves an important role in hypoxia-induced myocardial cell injury by regulating the miR‑145‑5p‑Binp3 axis.

Science.gov (United States)

Wu, Zhongwei; Zhao, Shengji; Li, Chunfu; Liu, Chaoquan

2018-02-01

The aim of the present study was to investigate the function of long non‑coding RNA TUG1 in hypoxia‑induced myocardial cell injury and to explore the potential molecular mechanisms. The cardiomyocyte cell line H9c2 was cultured under hypoxic and normoxic conditions. TUG1 expression under hypoxic conditions was then detected. The effects of TUG1 overexpression on viability, apoptosis, migration and invasion were assayed. In addition, the microRNA (miR)‑145‑5p expression was detected. Following H9c2 cell transfection with miR‑145‑5p mimics, the H9c2 cell viability, apoptosis, migration and invasion were also detected. Additionally, the target gene of miR‑145‑5p was assayed by Luciferase reporter assay. The protein expressions of Wnt‑3a, Wnt5a, and β‑catenin in H9c2 cells under hypoxic conditions were also determined. The results revealed that hypoxia induced injury in H9c2 cells, including inhibiting cell viability, migration and invasion, and promoting cell apoptosis. Overexpression of TUG1 aggravated hypoxia‑induced injury in H9c2 cells. In addition, miR‑145‑5p was negatively regulated by TUG1, and TUG1 overexpression aggravated hypoxia‑induced injury via the downregulation of miR‑145‑5p. Furthermore, B‑cell lymphoma 2 interacting protein 3 (Bnip3) was a target of miR‑145‑5p, and overexpression of Bnip3 aggravated hypoxia‑induced cell injury by activating Wnt/β‑catenin signaling pathways in H9c2 cells. In conclusion, overexpression of TUG1 aggravated hypoxia‑induced injury in cardiomyocytes by regulating the miR‑145‑5p‑Binp3 axis. Activation of the Wnt/β‑catenin signaling pathway may be a key mechanism to mediate the role of TUG1 in regulating hypoxia‑induced myocardial injury. TUG1 may be an effective diagnostic marker and therapeutic target for myocardial ischemia.

The 11th Annual Mediterranean Ad Hoc Networking Workshop (Med-Hoc-Net 2012)

NARCIS (Netherlands)

Pitsillides, A.; Douligeris, C.; Vassiliou, V.; Heijenk, Geert; Cavalcante de Oliveira, J.

Message from the General Chairs Welcome to the 2012 Mediterranean Ad Hoc Networking Workshop in Ayia Napa, Cyprus. We are excited to host Med-Hoc-Net. As a major annual international workshop, following recent successful workshops in Sicily (2006), Corfu (2007), Palma de Mallorca (2008), Haifa

Mobile ad hoc networking

CERN Document Server

John Wiley & Sons

2004-01-01

"Assimilating the most up-to-date information on research and development activities in this rapidly growing area, Mobile Ad Hoc Networking covers physical, data link, network, and transport layers, as well as application, security, simulation, and power management issues in sensor, local area, personal, and mobile ad hoc networks. Each of the book's sixteen chapters has been written by a top expert and discusses in-depth the most important topics in the field. Mobile Ad Hoc Networking is an excellent reference and guide for professionals seeking an in-depth examination of topics that also provides a comprehensive overview of the current state-of-the-art."--Jacket.

Astrionic system optimization and modular astrionics for NASA missions after 1974. Preliminary definition of astrionic system for space tug Mission Vehicle Payload (MVP)

Science.gov (United States)

1970-01-01

Results of preliminary studies to define the space tug astrionic system, subsystems, and components to meet requirements for a variety of missions are reported. Emphasis is placed on demonstration of the modular astrionics approach in the design of the space tug astrionic system.

P53-regulated long non-coding RNA TUG1 affects cell proliferation in human non-small cell lung cancer, partly through epigenetically regulating HOXB7 expression.

Science.gov (United States)

Zhang, E-b; Yin, D-d; Sun, M; Kong, R; Liu, X-h; You, L-h; Han, L; Xia, R; Wang, K-m; Yang, J-s; De, W; Shu, Y-q; Wang, Z-x

2014-05-22

Recently, a novel class of transcripts, long non-coding RNAs (lncRNAs), is being identified at a rapid pace. These RNAs have critical roles in diverse biological processes, including tumorigenesis. Here we report that taurine-upregulated gene 1 (TUG1), a 7.1-kb lncRNA, recruiting and binding to polycomb repressive complex 2 (PRC2), is generally downregulated in non-small cell lung carcinoma (NSCLC) tissues. In a cohort of 192 NSCLC patients, the lower expression of TUG1 was associated with a higher TNM stage and tumor size, as well as poorer overall survival (PTUG1 expression serves as an independent predictor for overall survival (PTUG1 expression was induced by p53, and luciferase and chromatin immunoprecipitation (ChIP) assays confirmed that TUG1 was a direct transcriptional target of p53. TUG1 knockdown significantly promoted the proliferation in vitro and in vivo. Moreover, the lncRNA-mediated regulation of the expression of HOX genes in tumorigenesis and development has been recently receiving increased attention. Interestingly, inhibition of TUG1 could upregulate homeobox B7 (HOXB7) expression; ChIP assays demonstrated that the promoter of HOXB7 locus was bound by EZH2 (enhancer of zeste homolog 2), a key component of PRC2, and was H3K27 trimethylated. This TUG1-mediated growth regulation is in part due to specific modulation of HOXB7, thus participating in AKT and MAPK pathways. Together, these results suggest that p53-regulated TUG1 is a growth regulator, which acts in part through control of HOXB7. The p53/TUG1/PRC2/HOXB7 interaction might serve as targets for NSCLC diagnosis and therapy.

Tanshinol suppresses endothelial cells apoptosis in mice with atherosclerosis via lncRNA TUG1 up-regulating the expression of miR-26a.

Science.gov (United States)

Chen, Chao; Cheng, Guangqing; Yang, Xiaoni; Li, Changsheng; Shi, Ran; Zhao, Ningning

2016-01-01

Endothelial cell (EC) apoptosis is a crucial process for the development of atherosclerosis. Tanshinol is reported to protect vascular endothelia and attenuate the formation of atherosclerosis. However, the potential molecule mechanism of the protective role of tanshinol in atherosclerosis need to be further investigated. ApoE(-/-)mice were fed with a high-fat diet and treated with tanshinol to detect the effect of tanshinol on endothelial cells apoptosis with TUNEL staining assay. qRT-PCR and Western blot were performed to examine the expression of TUG1 and miR-26a in endothelial cells. RNA-binding protein immunoprecipitation assay was performed to verify the relationship between TUG1 and miR-26a. It has been shown that tanshinol reduced the aortic atherosclerotic lesion area in the entire aorta and aortic sinus in a concentration dependent manner, and suppressed the endothelial cells apoptosis in ApoE(-/-) mice. We further found that the mRNA level of TUG1 was reduced and the expression of miR-26a was up-regulated by tanshinol in endothelial cells. In addition, TUG1 down-regulated the expression of miR-26a in ECV304 cells. Finally, it was shown that overexpression of TUG1 removed the reversed effect of tanshinol on oxidized low-density lipoprotein (ox-LDL)-induced endothelial cells apoptosis. Taken together, our study reveals that tanshinol could attenuate the endothelial cells apoptosis in atherosclerotic ApoE(-/-) mice. Moreover, low TUG1 expression and high level of miR-26a are associated with the endothelial protecting effect of tanshinol.

An in vitro study of the long non-coding RNA TUG1 in tongue squamous cell carcinoma.

Science.gov (United States)

Li, Zhi-Qiang; Zou, Rui; Ouyang, Ke-Xiong; Ai, Wei-Jian

2017-11-01

This study sought to study the expression of the long non-coding RNA (lncRNA) taurine-upregulated gene 1 (TUG1) in tongue squamous cell carcinoma (TSCC) and reveal its possible function. qRT-PCR was used to evaluate 27 samples of fresh TSCC tissues and adjacent normal tongue tissues. siRNA technology was employed to downregulate TUG1 expression in CAL-27 and SCC-9 cell lines. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay was utilized to assess cell proliferation ability; apoptosis and cell-cycle phases were analysed via flow cytometry. qRT-PCR findings indicated that the lncRNA TUG1 was upregulated in TSCC tissues compared with adjacent normal tongue tissues (PTUG1 expression was downregulated using siRNA technology, cell proliferation was significantly inhibited (PTUG1 may represent a potential oncogene in TSCC. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Aberrant expression of PlncRNA-1 and TUG1: potential biomarkers for gastric cancer diagnosis and clinically monitoring cancer progression.

Science.gov (United States)

Baratieh, Zohreh; Khalaj, Zahra; Honardoost, Mohammad Amin; Emadi-Baygi, Modjtaba; Khanahmad, Hossein; Salehi, Mansoor; Nikpour, Parvaneh

2017-12-01

To evaluate PlncRNA-1, TUG1 and FAM83H-AS1 gene expression and their possible role as a biomarker in gastric cancer (GC) progression. Long noncoding RNA expressions and clinicopathological characteristics were assessed in 70 paired GC tissues. Furthermore, corresponding data from 318 GC patients were downloaded from The Cancer Genome Atlas database. Expression of PlncRNA-1 and TUG1 were significantly upregulated in GC tumoral tissues, and significantly correlated with clinicopathological characters. However, FAM83H-AS1 showed no consistently differential expression. The expression of these three long noncoding RNAs was significantly higher in The Cancer Genome Atlas tumoral tissues. In conclusion, PlncRNA-1 and TUG1 genes may play a critical role in GC progression and may serve as potential diagnostic biomarkers in GC patients.

Steady-state Manoeuvring of a Generic ASD Tug in Escort Pull and Bow-rope Aided Push Operation

Directory of Open Access Journals (Sweden)

Jaroslaw Artyszuk

2014-09-01

Full Text Available This paper is devoted to expand the very promising research undertaken in the author's previous work, basically done on simplified modelling the escort push operation. Now, the other two modes of a tug's employment, as stated in the title, are covered. The special focus is again set on the indirect towing in that the towline force is much higher than the thruster force. The ratio of these two forces, referred to as the relative towing force (or amplification ratio is evaluated together with the hull drift angle and the thruster(-s angle for a given escort speed. This mutual relationship is known as the tug performance diagram. Although rather generic (container-type formulas are derived, they are supplied for exemplification purposes with simple, analytically given hull hydrodynamic forces. The aim is also here to provide a basis for further sensitivity analysis of the model and possible improvement/optimisation to the tug design. The obtained charts also could serve as rough and clear guidance for towmasters while escorting.

Long non-coding RNA TUG1 inhibits apoptosis and inflammatory response in LPS-treated H9c2 cells by down-regulation of miR-29b.

Science.gov (United States)

Zhang, Haifang; Li, Hui; Ge, Ang; Guo, Enyu; Liu, Shuxia; Zhang, Lijuan

2018-05-01

Myocarditis is an important cause for cardiovascular morbidity and mortality in children and adults. The lncRNA taurine up-regulated gene 1 (TUG1) plays important roles in cell apoptosis and inflammation in tumor and liver injury. The present study aimed to investigate the role of TUG1 in LPS-injured H9c2 cells and explore the underlying molecular mechanism. H9c2 cells were stimulated with LPS to induce inflammatory injury. The expression of TUG1 was altered by transient transfections. Cell viability and apoptotic cell rates were detected by CCK-8 assay and flow cytometry assay, respectively. Inflammatory response was determined by detecting levels of inflammatory cytokines using qRT-PCR and ELISA. Furthermore, western blot analysis was conducted to assess the expression levels of core factors related with apoptosis and activations of NF-κB and JAK/STAT signaling pathways. LPS exposure reduced cell viability but enhanced cell apoptosis and inflammation in H9c2 cells. Moreover, TUG1 expression was down-regulated in LPS-injured H9c2 cells. TUG1 overexpression attenuated LPS-induced injuries in H9c2 cells, evidenced by augmented cell viability, declined apoptotic cell rates and decreased levels of pro-apoptotic factors and inflammatory cytokines. Inversely, TUG1 inhibition exerted the opposite effects. More importantly, TUG1 negatively modulated the expression of miR-29b and miR-29b mimic blocked the effect of TUG1 overexpression on cell viability, apoptosis, inflammation and inactivation of NF-κB and JAK/STAT signaling pathways in LPS-stimulated H9c2 cells. This study demonstrated that TUG1 played the anti-apoptotic and anti-inflammatory roles in LPS-injured H9c2 cells via down-regulating miR-29b and inhibiting NF-κB and JAK/STAT pathways. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Operations analysis (study 2.1). Program SEPSIM (solar electric propulsion stage simulation). [in FORTRAN: space tug

Science.gov (United States)

Lang, T. J.

1974-01-01

Program SEPSIM is a FORTRAN program which performs deployment, servicing, and retrieval missions to synchronous equatorial orbit using a space tug with a continuous low thrust upper stage known as a solar electric propulsion stage (SEPS). The SEPS ferries payloads back and forth between an intermediate orbit and synchronous orbit, and performs the necessary servicing maneuvers in synchronous orbit. The tug carries payloads between the orbiter and the intermediate orbit, deploys fully fueled SEPS vehicles, and retrieves exhausted SEPS vehicles when, and if, required. The program is presently contained in subroutine form in the Logistical On-orbit VEhicle Servicing (LOVES) Program, but can also be run independently with the addition of a simple driver program.

Evaluating the Effect of Cognitive Dysfunction on Mental Imagery in Patients with Stroke Using Temporal Congruence and the Imagined 'Timed Up and Go' Test (iTUG.

Directory of Open Access Journals (Sweden)

Maxime Geiger

Full Text Available Motor imagery (MI capacity may be altered following stroke. MI is evaluated by measuring temporal congruence between the timed performance of an imagined and an executed task. Temporal congruence between imagined and physical gait-related activities has not been evaluated following stroke. Moreover, the effect of cognitive dysfunction on temporal congruence is not known.To assess temporal congruence between the Timed Up and Go test (TUG and the imagined TUG (iTUG tests in patients with stroke and to investigate the role played by cognitive dysfunctions in changes in temporal congruence.TUG and iTUG performance were recorded and compared in twenty patients with chronic stroke and 20 controls. Cognitive function was measured using the Montreal Cognitive Assessment (MOCA, the Frontal Assessment Battery at Bedside (FAB and the Bells Test.The temporal congruence of the patients with stroke was significantly altered compared to the controls, indicating a loss of MI capacity (respectively 45.11 ±35.11 vs 24.36 ±17.91, p = 0.02. Furthermore, iTUG test results were positively correlated with pathological scores on the Bells Test (r = 0.085, p = 0.013, likely suggesting that impairment of attention was a contributing factor.These results highlight the importance of evaluating potential attention disorder in patients with stroke to optimise the use of MI for rehabilitation and recovery. However further study is needed to determine how MI should be used in the case of cognitive dysfunction.

Evaluating the Effect of Cognitive Dysfunction on Mental Imagery in Patients with Stroke Using Temporal Congruence and the Imagined 'Timed Up and Go' Test (iTUG).

Science.gov (United States)

Geiger, Maxime; Bonnyaud, Céline; Fery, Yves-André; Bussel, Bernard; Roche, Nicolas

2017-01-01

Motor imagery (MI) capacity may be altered following stroke. MI is evaluated by measuring temporal congruence between the timed performance of an imagined and an executed task. Temporal congruence between imagined and physical gait-related activities has not been evaluated following stroke. Moreover, the effect of cognitive dysfunction on temporal congruence is not known. To assess temporal congruence between the Timed Up and Go test (TUG) and the imagined TUG (iTUG) tests in patients with stroke and to investigate the role played by cognitive dysfunctions in changes in temporal congruence. TUG and iTUG performance were recorded and compared in twenty patients with chronic stroke and 20 controls. Cognitive function was measured using the Montreal Cognitive Assessment (MOCA), the Frontal Assessment Battery at Bedside (FAB) and the Bells Test. The temporal congruence of the patients with stroke was significantly altered compared to the controls, indicating a loss of MI capacity (respectively 45.11 ±35.11 vs 24.36 ±17.91, p = 0.02). Furthermore, iTUG test results were positively correlated with pathological scores on the Bells Test (r = 0.085, p = 0.013), likely suggesting that impairment of attention was a contributing factor. These results highlight the importance of evaluating potential attention disorder in patients with stroke to optimise the use of MI for rehabilitation and recovery. However further study is needed to determine how MI should be used in the case of cognitive dysfunction.

Comparison of Efficacy and Safety of Liraglutide 3.0 mg in Individuals with BMI above and below 35 kg/m²: A Post-hoc Analysis

Science.gov (United States)

le Roux, Carel; Aroda, Vanita; Hemmingsson, Joanna; Cancino, Ana Paula; Christensen, Rune; Pi-Sunyer, Xavier

2018-01-01

Objective To investigate whether the efficacy and safety of liraglutide 3.0 mg differed between two subgroups, BMI 27 to 3.0 mg were evaluated by testing the interaction between treatment group and baseline BMI subgroup. Results Significantly greater weight loss (0–56 weeks) was observed with liraglutide 3.0 mg versus placebo in all patient groups while on treatment. There was no evidence that the weight-lowering effect of liraglutide 3.0 mg differed between BMI subgroups (interaction p > 0.05). Similarly, for most secondary endpoints significantly greater improvements were observed with liraglutide 3.0 mg versus placebo, with no indication treatment effects differing between subgroups. The safety profile of liraglutide 3.0 mg was broadly similar across BMI subgroups. Conclusion This post-hoc analysis did not indicate any differences in the treatment effects, or safety profile, of liraglutide 3.0 mg for individuals with BMI 27 to 3.0 mg can therefore be considered for individuals with a BMI of ≥35 as well as for those with a BMI of 27 to <35 kg/m². PMID:29145215

Space Tug avionics definition study. Volume 2: Avionics functional requirements

Science.gov (United States)

1975-01-01

Flight and ground operational phases of the tug/shuttle system are analyzed to determine the general avionics support functions that are needed during each of the mission phases and sub-phases. Each of these general support functions is then expanded into specific avionics system requirements, which are then allocated to the appropriate avionics subsystems. This process is then repeated at the next lower level of detail where these subsystem requirements are allocated to each of the major components that comprise a subsystem.

Intrusion detection in wireless ad-hoc networks

CERN Document Server

Chaki, Nabendu

2014-01-01

Presenting cutting-edge research, Intrusion Detection in Wireless Ad-Hoc Networks explores the security aspects of the basic categories of wireless ad-hoc networks and related application areas. Focusing on intrusion detection systems (IDSs), it explains how to establish security solutions for the range of wireless networks, including mobile ad-hoc networks, hybrid wireless networks, and sensor networks.This edited volume reviews and analyzes state-of-the-art IDSs for various wireless ad-hoc networks. It includes case studies on honesty-based intrusion detection systems, cluster oriented-based

Ad Hoc Access Gateway Selection Algorithm

Science.gov (United States)

Jie, Liu

With the continuous development of mobile communication technology, Ad Hoc access network has become a hot research, Ad Hoc access network nodes can be used to expand capacity of multi-hop communication range of mobile communication system, even business adjacent to the community, improve edge data rates. For mobile nodes in Ad Hoc network to internet, internet communications in the peer nodes must be achieved through the gateway. Therefore, the key Ad Hoc Access Networks will focus on the discovery gateway, as well as gateway selection in the case of multi-gateway and handover problems between different gateways. This paper considers the mobile node and the gateway, based on the average number of hops from an average access time and the stability of routes, improved gateway selection algorithm were proposed. An improved gateway selection algorithm, which mainly considers the algorithm can improve the access time of Ad Hoc nodes and the continuity of communication between the gateways, were proposed. This can improve the quality of communication across the network.

Evaluating the Effect of Cognitive Dysfunction on Mental Imagery in Patients with Stroke Using Temporal Congruence and the Imagined ‘Timed Up and Go’ Test (iTUG)

Science.gov (United States)

Bonnyaud, Céline; Fery, Yves-André; Bussel, Bernard; Roche, Nicolas

2017-01-01

Background Motor imagery (MI) capacity may be altered following stroke. MI is evaluated by measuring temporal congruence between the timed performance of an imagined and an executed task. Temporal congruence between imagined and physical gait-related activities has not been evaluated following stroke. Moreover, the effect of cognitive dysfunction on temporal congruence is not known. Objective To assess temporal congruence between the Timed Up and Go test (TUG) and the imagined TUG (iTUG) tests in patients with stroke and to investigate the role played by cognitive dysfunctions in changes in temporal congruence. Methods TUG and iTUG performance were recorded and compared in twenty patients with chronic stroke and 20 controls. Cognitive function was measured using the Montreal Cognitive Assessment (MOCA), the Frontal Assessment Battery at Bedside (FAB) and the Bells Test. Results The temporal congruence of the patients with stroke was significantly altered compared to the controls, indicating a loss of MI capacity (respectively 45.11 ±35.11 vs 24.36 ±17.91, p = 0.02). Furthermore, iTUG test results were positively correlated with pathological scores on the Bells Test (r = 0.085, p = 0.013), likely suggesting that impairment of attention was a contributing factor. Conclusion These results highlight the importance of evaluating potential attention disorder in patients with stroke to optimise the use of MI for rehabilitation and recovery. However further study is needed to determine how MI should be used in the case of cognitive dysfunction. PMID:28125616

Dynamic ad hoc networks

CERN Document Server

Rashvand, Habib

2013-01-01

Motivated by the exciting new application paradigm of using amalgamated technologies of the Internet and wireless, the next generation communication networks (also called 'ubiquitous', 'complex' and 'unstructured' networking) are changing the way we develop and apply our future systems and services at home and on local, national and global scales. Whatever the interconnection - a WiMAX enabled networked mobile vehicle, MEMS or nanotechnology enabled distributed sensor systems, Vehicular Ad hoc Networking (VANET) or Mobile Ad hoc Networking (MANET) - all can be classified under new networking s

LncRNA-TUG1/EZH2 Axis Promotes Cell Proliferation, Migration And The EMT Phenotype Formation Through Sponging miR-382

OpenAIRE

Chen, Zongjing; Chen, Bicheng; Zhou, Mengtao; Sun, Hongwei; Zhao, Liang; Kong, Hongru

2017-01-01

Pancreatic carcinoma (PC) is the one of the most common and malignant cancer in the world. Despite many effort have been made in recent years, the survival rate of PC still remains unsatisfied. Therefore, investigating the mechanisms underlying the progression of PC might facilitate the development of novel treatments that improve patient prognosis. LncRNA Taurine Up-regulated Gene 1 (TUG1) was initially identified as a transcript up- regulated by taurine, siRNA-based depletion of TUG1 suppre...

Long noncoding RNA TUG1 alleviates extracellular matrix accumulation via mediating microRNA-377 targeting of PPARγ in diabetic nephropathy.

Science.gov (United States)

Duan, Li-Jun; Ding, Min; Hou, Li-Jun; Cui, Yuan-Tao; Li, Chun-Jun; Yu, De-Min

2017-03-11

Long noncoding RNA taurine-upregulated gene 1 (lncRNA TUG1) has been reported to play a key role in the progression of diabetic nephropathy (DN). However, the role of lncRNA TUG1 in the regulation of diabetic nephropathy remains largely unknown. The aim of the present study is to identify the regulation of lncRNA TUG1 on extracellular matrix accumulation via mediating microRNA-377 targeting of PPARγ, and investigate the underlying mechanisms in progression of DN. Microarray was performed to screen differentially expressed miRNAs in db/db DN mice. Afterwards, computational prediction programs (TargetScan, miRanda, PicTar and miRGen) was applied to predict the target gene of miRNAs. The complementary binding of miRNA and lncRNA was assessed by luciferase assays. Protein and mRNA expression were detected by western blot and real time quantitate PCR. MiRNA-377 was screened by miRNA microarray and differentially up-regulated in db/db DN mice. PPARγ was predicted to be the target of miR-377 and the prediction was verified by luciferase assays. Expression of miR-377 was up-regulated in mesangial cell treated with high glucose (25 mM), and overexpression of miR-377 inhibited PPARγ expression and promoted PAI-1 and TGF-β1 expression. The expression of TUG1 antagonized the effect of miR-377 on the downregulation of its target PPARγ and inhibited extracellular matrix accumulation, including PAI-1, TGF-β1, fibronectin (FN) and collagen IV (Col IV), induced by high glucose. LncRNA TUG1 acts as an endogenous sponge of miR-377 and downregulates miR-377 expression levels, and thereby relieving the inhibition of its target gene PPARγ and alleviates extracellular matrix accumulation of mesangial cells, which provides a novel insight of diabetic nephropathy pathogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

Interplay between FMRP and lncRNA TUG1 regulates axonal development through mediating SnoN-Ccd1 pathway.

Science.gov (United States)

Guo, Ye; Chen, Xu; Xing, Ruxiao; Wang, Min; Zhu, Xiaojuan; Guo, Weixiang

2018-02-01

LncRNAs have recently emerged to influence the pathogenesis of fragile X syndrome (FXS), which is caused by the functional loss of fragile X mental retardation protein (FMRP). However, the interaction between FMRP and lncRNAs on regulating neuronal development remains elusive. Here, we reported that FMRP directly interacted with lncRNA TUG1, and decreased its stability. Furthermore, TUG1 bond to transcriptional regulator, SnoN, and negatively modulated SnoN-Ccd1 pathway to specifically control axonal development. These observations suggested interplay between FMRP and lncRNAs might contribute to the pathogenesis of FXS. © The Author(s) 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Generating linear regression model to predict motor functions by use of laser range finder during TUG.

Science.gov (United States)

Adachi, Daiki; Nishiguchi, Shu; Fukutani, Naoto; Hotta, Takayuki; Tashiro, Yuto; Morino, Saori; Shirooka, Hidehiko; Nozaki, Yuma; Hirata, Hinako; Yamaguchi, Moe; Yorozu, Ayanori; Takahashi, Masaki; Aoyama, Tomoki

2017-05-01

The purpose of this study was to investigate which spatial and temporal parameters of the Timed Up and Go (TUG) test are associated with motor function in elderly individuals. This study included 99 community-dwelling women aged 72.9 ± 6.3 years. Step length, step width, single support time, variability of the aforementioned parameters, gait velocity, cadence, reaction time from starting signal to first step, and minimum distance between the foot and a marker placed to 3 in front of the chair were measured using our analysis system. The 10-m walk test, five times sit-to-stand (FTSTS) test, and one-leg standing (OLS) test were used to assess motor function. Stepwise multivariate linear regression analysis was used to determine which TUG test parameters were associated with each motor function test. Finally, we calculated a predictive model for each motor function test using each regression coefficient. In stepwise linear regression analysis, step length and cadence were significantly associated with the 10-m walk test, FTSTS and OLS test. Reaction time was associated with the FTSTS test, and step width was associated with the OLS test. Each predictive model showed a strong correlation with the 10-m walk test and OLS test (P motor function test. Moreover, the TUG test time regarded as the lower extremity function and mobility has strong predictive ability in each motor function test. Copyright © 2017 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

Context discovery in ad-hoc networks

NARCIS (Netherlands)

Liu, F.

2011-01-01

With the rapid development of wireless technology and portable devices, mobile ad-hoc networks (MANETs) are more and more present in our daily life. Ad-hoc networks are often composed of mobile and battery-supplied devices, like laptops, mobile phones, and PDAs. With no requirement for

Comparison of Efficacy and Safety of Liraglutide 3.0 mg in Individuals with BMI above and below 35 kg/m²: A Post-hoc Analysis.

Science.gov (United States)

le Roux, Carel; Aroda, Vanita; Hemmingsson, Joanna; Cancino, Ana Paula; Christensen, Rune; Pi-Sunyer, Xavier

2017-01-01

To investigate whether the efficacy and safety of liraglutide 3.0 mg differed between two subgroups, BMI 27 to 3.0 mg were evaluated by testing the interaction between treatment group and baseline BMI subgroup. Significantly greater weight loss (0-56 weeks) was observed with liraglutide 3.0 mg versus placebo in all patient groups while on treatment. There was no evidence that the weight-lowering effect of liraglutide 3.0 mg differed between BMI subgroups (interaction p > 0.05). Similarly, for most secondary endpoints significantly greater improvements were observed with liraglutide 3.0 mg versus placebo, with no indication treatment effects differing between subgroups. The safety profile of liraglutide 3.0 mg was broadly similar across BMI subgroups. This post-hoc analysis did not indicate any differences in the treatment effects, or safety profile, of liraglutide 3.0 mg for individuals with BMI 27 to 3.0 mg can therefore be considered for individuals with a BMI of ≥35 as well as for those with a BMI of 27 to <35 kg/m². © 2017 The Author(s) Published by S. Karger GmbH, Freiburg.

The long non-coding RNA TUG1 indicates a poor prognosis for colorectal cancer and promotes metastasis by affecting epithelial-mesenchymal transition

OpenAIRE

Sun, Junfeng; Ding, Chaohui; Yang, Zhen; Liu, Tao; Zhang, Xiefu; Zhao, Chunlin; Wang, Jiaxiang

2016-01-01

Background Long intergenic non-coding RNAs (lncRNAs) are a class of non-coding RNAs that are involved in gene expression regulation. Taurine up-regulated gene 1 (TUG1) is a cancer progression related lncRNA in some tumor oncogenesis; however, its role in colorectal cancer (CRC) remains unclear. In this study, we determined the expression patterns of TUG1 in CRC patients and explored its effect on CRC cell metastasis using cultured representative CRC cell lines. Methods The expression levels o...

Receiver-Based Ad Hoc On Demand Multipath Routing Protocol for Mobile Ad Hoc Networks.

Science.gov (United States)

Al-Nahari, Abdulaziz; Mohamad, Mohd Murtadha

2016-01-01

Decreasing the route rediscovery time process in reactive routing protocols is challenging in mobile ad hoc networks. Links between nodes are continuously established and broken because of the characteristics of the network. Finding multiple routes to increase the reliability is also important but requires a fast update, especially in high traffic load and high mobility where paths can be broken as well. The sender node keeps re-establishing path discovery to find new paths, which makes for long time delay. In this paper we propose an improved multipath routing protocol, called Receiver-based ad hoc on demand multipath routing protocol (RB-AOMDV), which takes advantage of the reliability of the state of the art ad hoc on demand multipath distance vector (AOMDV) protocol with less re-established discovery time. The receiver node assumes the role of discovering paths when finding data packets that have not been received after a period of time. Simulation results show the delay and delivery ratio performances are improved compared with AOMDV.

Research of Ad Hoc Networks Access Algorithm

Science.gov (United States)

Xiang, Ma

With the continuous development of mobile communication technology, Ad Hoc access network has become a hot research, Ad Hoc access network nodes can be used to expand capacity of multi-hop communication range of mobile communication system, even business adjacent to the community, improve edge data rates. When the ad hoc network is the access network of the internet, the gateway discovery protocol is very important to choose the most appropriate gateway to guarantee the connectivity between ad hoc network and IP based fixed networks. The paper proposes a QoS gateway discovery protocol which uses the time delay and stable route to the gateway selection conditions. And according to the gateway discovery protocol, it also proposes a fast handover scheme which can decrease the handover time and improve the handover efficiency.

Cytoarchitecture of the human lateral occipital cortex: mapping of two extrastriate areas hOc4la and hOc4lp.

Science.gov (United States)

Malikovic, Aleksandar; Amunts, Katrin; Schleicher, Axel; Mohlberg, Hartmut; Kujovic, Milenko; Palomero-Gallagher, Nicola; Eickhoff, Simon B; Zilles, Karl

2016-05-01

The microstructural correlates of the functional segregation of the human lateral occipital cortex are largely unknown. Therefore, we analyzed the cytoarchitecture of this region in ten human post-mortem brains using an observer-independent and statistically testable parcellation method to define the position and extent of areas in the lateral occipital cortex. Two new cytoarchitectonic areas were found: an anterior area hOc4la and a posterior area hOc4lp. hOc4la was located behind the anterior occipital sulcus in rostral and ventral portions of this region where it occupies the anterior third of the middle and inferior lateral occipital gyri. hOc4lp was found in caudal and dorsal portions of this region where it extends along the superior and middle lateral occipital gyri. The cytoarchitectonic areas were registered to 3D reconstructions of the corresponding brains, which were subsequently spatially normalized to the Montreal Neurological Institute reference space. Continuous probabilistic maps of both areas based on the analysis of ten brains were generated to characterize their inter-subject variability in location and size. The maps of hOc4la and hOc4lp were then used as seeds for meta-analytic connectivity modeling and quantitative functional decoding to identify their co-activation patterns and assignment to functional domains. Convergent evidence from their location, topography, size, functional domains and connectivity indicates that hOc4la and hOc4lp are the potential anatomical correlates of the functionally defined lateral occipital areas LO-1 and LO-2.

The Lunar Space Tug: A sustainable bridge between low Earth orbits and the Cislunar Habitat

Science.gov (United States)

Mammarella, M.; Paissoni, C. A.; Viola, N.; Denaro, A.; Gargioli, E.; Massobrio, F.

2017-09-01

The International Space Station is the first space human outpost and over the last 15 years, it has represented a peculiar environment where science, technology and human innovation converge together in a unique microgravity and space research laboratory. With the International Space Station entering the second part of its life and its operations running steadily at nominal pace, the global space community is starting planning how the human exploration could move further, beyond Low-Earth-Orbit. According to the Global Exploration Roadmap, the Moon represents the next feasible path-way for advances in human exploration towards the nal goal, Mars. Based on the experience of the ISS, one of the most widespread ideas is to develop a Cislunar Station in preparation of long duration missions in a deep space environment. Cislunar space is de ned as the area of deep space under the influence of Earth-Moon system, including a set of special orbits, e.g. Earth-Moon Libration points and Lunar Retrograde Orbit. This habitat represents a suitable environment for demonstrating and testing technologies and capabilities in deep space. In order to achieve this goal, there are several crucial systems and technologies, in particular related to transportation and launch systems. The Orion Multi-Purpose Crew Vehicle is a reusable transportation capsule designed to provide crew transportation in deep space missions, whereas NASA is developing the Space Launch System, the most powerful rocket ever built, which could provide the necessary heavy-lift launch capability to support the same kind of missions. These innovations would allow quite-fast transfers from Earth to the Cislunar Station and vice versa, both for manned and unmanned missions. However, taking into account the whole Concept of Operations for both the growth and sustainability of the Cislunar Space Station, the Lunar Space Tug can be considered as an additional, new and fundamental element for the mission architecture. The

Overexpression of Long Non-Coding RNA TUG1 Promotes Colon Cancer Progression

OpenAIRE

Zhai, Hui-yuan; Sui, Ming-hua; Yu, Xiao; Qu, Zhen; Hu, Jin-chen; Sun, Hai-qing; Zheng, Hai-tao; Zhou, Kai; Jiang, Li-xin

2016-01-01

Background Colon cancer is one of the most prevalent and deadly cancers worldwide. It is still necessary to further define the mechanisms and explore therapeutic targets of colon cancer. Dysregulation of long noncoding RNAs (lncRNAs) has been shown to be correlated with diverse biological processes, including tumorigenesis. This study aimed to characterize the biological mechanism of taurine-upregulated gene 1 (TUG1) in colon cancer. Material/Methods qRT-PCR was used to analyze the expression...

75 FR 15611 - Safety Zone; United Portuguese SES Centennial Festa, San Diego Bay, San Diego, CA

Science.gov (United States)

2010-03-30

...-AA00 Safety Zone; United Portuguese SES Centennial Festa, San Diego Bay, San Diego, CA AGENCY: Coast... navigable waters of the San Diego Bay in support of the United Portuguese SES Centennial Festa. This... Centennial Festa, which will include a fireworks presentation originating from a tug and barge combination in...

Radiosynthesis of [18F]FEt-Tyr-urea-Glu ([18F]FEtTUG) as a new PSMA ligand

International Nuclear Information System (INIS)

Al-Momani, E.; Malik, N.; Machulla, H.J.; Reske, S.N.; Solbach, C.

2013-01-01

An efficient radiosynthesis of [ 18 F]FEt-Tyr-urea-Glu ([ 18 F]FEtTUG) as a new ligand for prostate specific membrane antigen (PSMA) was developed by use of [ 18 F]fluoroethyltosylate as labeling precursor. The corresponding fluoroethyl-tyrosine-urea-glutamate peptide was prepared as reference standard for HPLC control and identified and characterized by standard procedures (MS, NMR). The labeling conditions were optimized with respect to reaction time, reaction temperature, base and solvent. The maximal radiochemical yield of [ 18 F]FEtTUG (77 ± 0.8 %) was obtained within a reaction time of 15 min at a reaction temperature of 80 deg C using 10 M NaOH (18 equiv. related to precursor) in 80 % aqueous acetonitrile. The total preparation time including radiosynthesis, hydrolysis, HPLC purification and formulation was 70 min (EOB). The radiochemical purity was ≥98 %. (author)

Comparison of two-way satellite time transfer and GPS common-view time transfer between OCA and TUG

Science.gov (United States)

Kirchner, Dieter; Thyr, U.; Ressler, H.; Robnik, R.; Grudler, P.; Baumont, Francoise S.; Veillet, Christian; Lewandowski, Wlodzimierz W.; Hanson, W.; Clements, A.

1992-01-01

For about one year the time scales UTC(OCA) and UTC(TUG) were compared by means of GPS and two-way satellite time transfer. At the end of the experiment both links were independently 'calibrated' by measuring the differential delays of the GPS receivers and of the satellite earth stations by transportation of a GPS receiver and of one of the satellite terminals. The results obtained by both methods differ by about 3 ns, but reveal a seasonal variation of about 8 ns peak-to-peak which is likely the result of a temperature-dependence of the delays of the GPS receivers used. For the comparison of both methods the stabilities of the timescales are of great importance. Unfortunately, during the last three months of the experiment a less stable clock had to be used for the generation of UTC(TUG).

Selective epidemic broadcast algorithm to suppress broadcast storm in vehicular ad hoc networks

Directory of Open Access Journals (Sweden)

M. Chitra

2018-03-01

Full Text Available Broadcasting in Vehicular Ad Hoc Networks is the best way to spread emergency messages all over the network. With the dynamic nature of vehicular ad hoc networks, simple broadcast or flooding faces the problem called as Broadcast Storm Problem (BSP. The issue of the BSP will degrade the performance of a message broadcasting process like increased overhead, collision and dissemination delay. The paper is motivated to solve the problems in the existing Broadcast Strom Suppression Algorithms (BSSAs like p-Persistence, TLO, VSPB, G-SAB and SIR. This paper proposes to suppress the Broadcast Storm Problem and to improve the Emergency Safety message dissemination rate through a new BSSA based on Selective Epidemic Broadcast Algorithm (SEB. The simulation results clearly show that the SEB outperforms the existing algorithms in terms of ESM Delivery Ratio, Message Overhead, Collision Ratio, Broadcast Storm Ratio and Redundant Rebroadcast Ratio with decreased Dissemination Delay.

AD HOC TEAMWORK BEHAVIORS FOR INFLUENCING A FLOCK

Directory of Open Access Journals (Sweden)

Katie Genter

2016-02-01

Full Text Available Ad hoc teamwork refers to the challenge of designing agents that can influence the behavior of a team, without prior coordination with its teammates. This paper considers influencing a flock of simple robotic agents to adopt a desired behavior within the context of ad hoc teamwork. Specifically, we examine how the ad hoc agents should behave in order to orient a flock towards a target heading as quickly as possible when given knowledge of, but no direct control over, the behavior of the flock. We introduce three algorithms which the ad hoc agents can use to influence the flock, and we examine the relative importance of coordinating the ad hoc agents versus planning farther ahead when given fixed computational resources. We present detailed experimental results for each of these algorithms, concluding that in this setting, inter-agent coordination and deeper lookahead planning are no more beneficial than short-term lookahead planning.

Routing Protocol for Mobile Ad-hoc Wireless Networks

Directory of Open Access Journals (Sweden)

I. M. B. Nogales

2007-09-01

Full Text Available Bluetooth is a cutting-edge technology used for implementing wireless ad hoc networks. In order to provide an overall scheme for mobile ad hoc networks, this paper deals with scatternet topology formation and routing algorithm to form larger ad hoc wireless Networks. Scatternet topology starts by forming a robust network, which is less susceptible to the problems posed by node mobility. Mobile topology relies on the presence of free nodes that create multiple connections with the network and on their subsequently rejoining the network. Our routing protocol is a proactive routing protocol, which is tailor made for the Bluetooth ad hoc network. The connection establishment connects nodes in a structure that simplifies packet routing and scheduling. The design allows nodes to arrive and leave arbitrarily, incrementally building the topology and healing partitions when they occur. We present simulation results that show that the algorithm presents low formation latency and also generates an efficient topology for forwarding packets along ad-hoc wireless networks.

Extending Service Area of IEEE 802.11 Ad Hoc Networks

Science.gov (United States)

Choi, Woo-Yong

2012-06-01

According to the current IEEE 802.11 wireless LAN standards, IEEE 802.11 ad hoc networks have the limitation that all STAs (Stations) are in the one-hop transmission range of each other. In this paper, to alleviate the limitation of IEEE 802.11 ad hoc networks we propose the efficient method for selecting the most appropriate pseudo AP (Access Point) from among the set of ad hoc STAs and extending the service area of IEEE 802.11 ad hoc networks by the pseudo AP's relaying the internal traffic of IEEE 802.11 ad hoc networks. Numerical examples show that the proposed method significantly extends the service area of IEEE 802.11 ad hoc networks.

Queueing Models for Mobile Ad Hoc Networks

NARCIS (Netherlands)

de Haan, Roland

2009-01-01

This thesis presents models for the performance analysis of a recent communication paradigm: \\emph{mobile ad hoc networking}. The objective of mobile ad hoc networking is to provide wireless connectivity between stations in a highly dynamic environment. These dynamics are driven by the mobility of

Assured Resource Sharing in Ad-Hoc Collaboration

Energy Technology Data Exchange (ETDEWEB)

Ahn, Gail-Joon [Arizona State Univ., Tempe, AZ (United States)

2015-12-19

The project seeks an innovative framework to enable users to access and selectively share resources in distributed environments, enhancing the scalability of information sharing. We have investigated secure sharing & assurance approaches for ad-hoc collaboration, focused on Grids, Clouds, and ad-hoc network environments.

Game Theory in Wireless Ad-Hoc Opportunistic Radios

OpenAIRE

Mumtaz, Shahid; Gameiro, Atilio

2010-01-01

Emerging research in game theory based power control applied to ad hoc opportunist networks shows much promise to help understand the complex interactions between OR nodes in this highly dynamic and distributed environment. Also, the employment of game theory in modeling dynamic situations for opportunist ad hoc networks where OR nodes have incomplete information has led to the application of largely unexplored games such as games of imperfect monitoring. Ad hoc security using game theory is ...

The Ex hoc Architecture

DEFF Research Database (Denmark)

2006-01-01

Developed in the LIWAS project which develops technology for measuring road surfaces and communicating this data in an ad hoc environment. The communication part is built upon OOVM Resilient technology....

Cognitive radio network in vehicular ad-hoc network (VANET: A survey

Directory of Open Access Journals (Sweden)

Joanne Mun-Yee Lim

2016-05-01

Full Text Available Cognitive radio network and Vehicular Ad hoc Network (VANET are recent emerging concepts in wireless networking. Cognitive radio network obtains knowledge of its operational geographical environment to manage sharing of spectrum between primary and secondary users, while VANET shares emergency safety messages among vehicles to ensure safety of users on the road. Cognitive radio network is employed in VANET to ensure the efficient use of spectrum, as well as to support VANET’s deployment. Random increase and decrease of spectrum users, unpredictable nature of VANET, high mobility, varying interference, security, packet scheduling and priority assignment are the challenges encountered in a typical cognitive VANET environment. This paper provides survey and critical analysis on different challenges of cognitive radio VANET, with discussion on the open issues, challenges and performance metrics, for different cognitive radio VANET applications.

Innovative research of AD HOC network mobility model

Science.gov (United States)

Chen, Xin

2017-08-01

It is difficult for researchers of AD HOC network to conduct actual deployment during experimental stage as the network topology is changeable and location of nodes is unfixed. Thus simulation still remains the main research method of the network. Mobility model is an important component of AD HOC network simulation. It is used to describe the movement pattern of nodes in AD HOC network (including location and velocity, etc.) and decides the movement trail of nodes, playing as the abstraction of the movement modes of nodes. Therefore, mobility model which simulates node movement is an important foundation for simulation research. In AD HOC network research, mobility model shall reflect the movement law of nodes as truly as possible. In this paper, node generally refers to the wireless equipment people carry. The main research contents include how nodes avoid obstacles during movement process and the impacts of obstacles on the mutual relation among nodes, based on which a Node Self Avoiding Obstacle, i.e. NASO model is established in AD HOC network.

Safety Culture Monitoring: How to Assess Safety Culture in Real Time?

International Nuclear Information System (INIS)

Zronek, B.; Maryska, J.; Treslova, L.

2016-01-01

Do you know what is current level of safety culture in your company? Are you able to follow trend changes? Do you know what your recent issues are? Since safety culture is understood as vital part of nuclear industry daily life, it is crucial to know what the current level is. It is common to perform safety culture survey or ad hoc assessment. This contribution shares Temelin NPP, CEZ approach how to assess safety culture level permanently. Using behavioral related outputs of gap solving system, observation program, dedicated surveys, regulatory assessment, etc., allows creating real time safety culture monitoring without the need to perform any other activities. (author)

Report of the independent Ad Hoc Group for the Davis-Besse incident

International Nuclear Information System (INIS)

1986-06-01

The Nuclear Regulatory Commission established an independent Ad Hoc Group in January 1986 to review issues subsequent to a complete loss of feedwater event at Davis-Besse Nuclear Power Station on June 9, 1985, including the NRC Incident Investigation Team (IIT) investigation of that event. The Commission asked the Group to identify additional lessons that might be learned and from these to make recommendations to improve NRC oversight of reactor licensees. To fulfill its charter, the Ad Hoc Group examined the following: (1) pre-event interactions between the licensee and NRC concerning reliability of the auxiliary feedwater system and associated systems; (2) pre-event probabilistic assessments of the reliability of plant safety systems, NRC's review of them, and their use in regulatory decisionmaking; (3) licensee management, operation and maintenance programs as they may have contributed to equipment failures and NRC oversight of such programs; and (4) the mandate, capabilities of members, operation, and results of the NRC Davis-Besse IIT, and the use to which its report was put by the regulatory staff

Hearings before the Ad Hoc Committee on Maritime Education and Training of the Committee on Merchant Marine and Fisheries, Ninety-Third Congress; Second Session on Officer Requirements, and Session on Maritime Education Regarding Safety at Sea. Serial No. 93-44.

Science.gov (United States)

Congress of the U.S., Washington, DC. House Committee on Merchant Marine and Fisheries.

The publication consists of Congressional hearings before the Ad Hoc Committee on Maritime Education and Training: (1) June 26, 1974 hearing pertaining to officer requirements and (2) November 19, 1974 hearing on maritime education regarding safety at sea. Estimated cost per graduate for the U. S. Merchant Marine 1973 class was $31,100. Supply and…

The GPR120 agonist TUG-891 promotes metabolic health by stimulating mitochondrial respiration in brown fat

DEFF Research Database (Denmark)

Schilperoort, Maaike; van Dam, Andrea D; Hoeke, Geerte

2018-01-01

the therapeutic potential of GPR120 agonism and addressed GPR120-mediated signaling in BAT We found that activation of GPR120 by the selective agonist TUG-891 acutely increases fat oxidation and reduces body weight and fat mass in C57Bl/6J mice. These effects coincided with decreased brown adipocyte lipid content...

Broadcast design in cognitive radio ad hoc networks

CERN Document Server

Song, Yi

2014-01-01

This SpringerBrief investigates the special challenges of broadcast design in cognitive radio (CR) ad hoc networks. It introduces two broadcast protocols in CR ad hoc networks: a quality-of-service based broadcast protocol under blind information and a fully-distributed broadcast protocol with collision avoidance. A novel unified analytical model is also presented to analyze the performance of the broadcast protocols. This is the first book dedicated to the unique broadcast design challenges in CR ad hoc networks. The authors also discuss the recent research on the performance analysis of broa

An Efficient and QoS Supported Multichannel MAC Protocol for Vehicular Ad Hoc Networks.

Science.gov (United States)

Song, Caixia; Tan, Guozhen; Yu, Chao

2017-10-09

Vehicular Ad Hoc Networks (VANETs) employ multichannel to provide a variety of safety and non-safety (transport efficiency and infotainment) applications, based on the IEEE 802.11p and IEEE 1609.4 protocols. Different types of applications require different levels Quality-of-Service (QoS) support. Recently, transport efficiency and infotainment applications (e.g., electronic map download and Internet access) have received more and more attention, and this kind of applications is expected to become a big market driver in a near future. In this paper, we propose an Efficient and QoS supported Multichannel Medium Access Control (EQM-MAC) protocol for VANETs in a highway environment. The EQM-MAC protocol utilizes the service channel resources for non-safety message transmissions during the whole synchronization interval, and it dynamically adjusts minimum contention window size for different non-safety services according to the traffic conditions. Theoretical model analysis and extensive simulation results show that the EQM-MAC protocol can support QoS services, while ensuring the high saturation throughput and low transmission delay for non-safety applications.

An Efficient and QoS Supported Multichannel MAC Protocol for Vehicular Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Caixia Song

2017-10-01

Full Text Available Vehicular Ad Hoc Networks (VANETs employ multichannel to provide a variety of safety and non-safety (transport efficiency and infotainment applications, based on the IEEE 802.11p and IEEE 1609.4 protocols. Different types of applications require different levels Quality-of-Service (QoS support. Recently, transport efficiency and infotainment applications (e.g., electronic map download and Internet access have received more and more attention, and this kind of applications is expected to become a big market driver in a near future. In this paper, we propose an Efficient and QoS supported Multichannel Medium Access Control (EQM-MAC protocol for VANETs in a highway environment. The EQM-MAC protocol utilizes the service channel resources for non-safety message transmissions during the whole synchronization interval, and it dynamically adjusts minimum contention window size for different non-safety services according to the traffic conditions. Theoretical model analysis and extensive simulation results show that the EQM-MAC protocol can support QoS services, while ensuring the high saturation throughput and low transmission delay for non-safety applications.

Decentralized position verification in geographic ad hoc routing

NARCIS (Netherlands)

Leinmüller, Tim; Schoch, Elmar; Kargl, Frank; Maihöfer, Christian

Inter-vehicle communication is regarded as one of the major applications of mobile ad hoc networks (MANETs). Compared to MANETs or wireless sensor networks (WSNs), these so-called vehicular ad hoc networks (VANETs) have unique requirements on network protocols. The requirements result mainly from

Ad hoc committee on reactor physics benchmarks

International Nuclear Information System (INIS)

Diamond, D.J.; Mosteller, R.D.; Gehin, J.C.

1996-01-01

In the spring of 1994, an ad hoc committee on reactor physics benchmarks was formed under the leadership of two American Nuclear Society (ANS) organizations. The ANS-19 Standards Subcommittee of the Reactor Physics Division and the Computational Benchmark Problem Committee of the Mathematics and Computation Division had both seen a need for additional benchmarks to help validate computer codes used for light water reactor (LWR) neutronics calculations. Although individual organizations had employed various means to validate the reactor physics methods that they used for fuel management, operations, and safety, additional work in code development and refinement is under way, and to increase accuracy, there is a need for a corresponding increase in validation. Both organizations thought that there was a need to promulgate benchmarks based on measured data to supplement the LWR computational benchmarks that have been published in the past. By having an organized benchmark activity, the participants also gain by being able to discuss their problems and achievements with others traveling the same route

Ad hoc mobile wireless networks principles, protocols and applications

CERN Document Server

Sarkar, Subir Kumar; Puttamadappa, C

2007-01-01

Ad hoc mobile wireless networks have seen increased adaptation in a variety of disciplines because they can be deployed with simple infrastructures and virtually no central administration. In particular, the development of ad hoc wireless and sensor networks provides tremendous opportunities in areas including disaster recovery, defense, health care, and industrial environments. Ad Hoc Mobile Wireless Networks: Principles, Protocols and Applications explains the concepts, mechanisms, design, and performance of these systems. It presents in-depth explanations of the latest wireless technologies

Ad hoc mobile wireless networks principles, protocols, and applications

CERN Document Server

Sarkar, Subir Kumar

2013-01-01

The military, the research community, emergency services, and industrial environments all rely on ad hoc mobile wireless networks because of their simple infrastructure and minimal central administration. Now in its second edition, Ad Hoc Mobile Wireless Networks: Principles, Protocols, and Applications explains the concepts, mechanism, design, and performance of these highly valued systems. Following an overview of wireless network fundamentals, the book explores MAC layer, routing, multicast, and transport layer protocols for ad hoc mobile wireless networks. Next, it examines quality of serv

Analysis of Pervasive Mobile Ad Hoc Routing Protocols

Science.gov (United States)

Qadri, Nadia N.; Liotta, Antonio

Mobile ad hoc networks (MANETs) are a fundamental element of pervasive networks and therefore, of pervasive systems that truly support pervasive computing, where user can communicate anywhere, anytime and on-the-fly. In fact, future advances in pervasive computing rely on advancements in mobile communication, which includes both infrastructure-based wireless networks and non-infrastructure-based MANETs. MANETs introduce a new communication paradigm, which does not require a fixed infrastructure - they rely on wireless terminals for routing and transport services. Due to highly dynamic topology, absence of established infrastructure for centralized administration, bandwidth constrained wireless links, and limited resources in MANETs, it is challenging to design an efficient and reliable routing protocol. This chapter reviews the key studies carried out so far on the performance of mobile ad hoc routing protocols. We discuss performance issues and metrics required for the evaluation of ad hoc routing protocols. This leads to a survey of existing work, which captures the performance of ad hoc routing algorithms and their behaviour from different perspectives and highlights avenues for future research.

Human Costs Assessment - The Impacts of Flooding & Nonstructural Solutions. Tug Fork Valley, West Virginia & Kentucky.

Science.gov (United States)

1980-04-01

to the outside world (especially in the West Virginia side). New people are being drawn in and there is a continuing out migration. Franchised ...all of these businesses are local ones suggesting the skillful entrepreneurship of area people and the recognition of Goody’s existence in the larger...chain stores and franchise businesses. The net effect is that here is another instance in which the Tug Fork people are dependent upon outsiders. King

Hydrogeology of Two Areas of the Tug Hill Glacial-Drift Aquifer, Oswego County, New York

Science.gov (United States)

Miller, Todd S.; Bugliosi, Edward F.; Hetcher-Aguila, Kari K.; Eckhardt, David A.

2007-01-01

Two water-production systems, one for the Village of Pulaski and the other for the Villages of Sandy Creek and Lacona in Oswego County, New York, withdraw water from the Tug Hill glacial-drift aquifer, a regional sand and gravel aquifer along the western flank of the Tug Hill Plateau, and provide the sole source of water for these villages. As a result of concerns about contamination of the aquifer, two studies were conducted during 2001 to 2004, one for each water-production system, to refine the understanding of ground-water flow surrounding these water-production systems. Also, these studies were conducted to determine the cause of the discrepancy between ground-water ages estimated from previously constructed numerical ground-water-flow models for the Pulaski and Sandy Creek/Lacona well fields and the apparent ground-water ages determined using concentrations of tritium and chlorofluorocarbons. The Village of Pulaski withdrew 650,000 gallons per day in 2000 from four shallow, large-diameter, dug wells finished in glaciolacustrine deposits consisting of sand with some gravelly lenses 3 miles east of the village. Four 2-inch diameter test wells were installed upgradient from each production well, hydraulic heads were measured, and water samples collected and analyzed for physical properties, inorganic constituents, nutrients, bacteria, tritium, dissolved gases, and chlorofluorocarbons. Recharge to the Tug Hill glacial-drift aquifer is from precipitation directly over the aquifer and from upland sources in the eastern part of the recharge area, including (1) unchannelized runoff from till and bedrock hills east of the aquifer, (2) seepage to the aquifer from streams that drain the Tug Hill Plateau, (3) ground-water inflow from the till and bedrock on the adjoining Tug Hill Plateau. Water-quality data collected from four piezometers near the production wells in November 2003 indicated that the water is a calcium-bicarbonate type with iron concentrations that

A Mobility-Aware Link Enhancement Mechanism for Vehicular Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Kai-Wen Hu

2008-04-01

Full Text Available With the growth up of internet in mobile commerce, researchers have reproduced various mobile applications that vary from entertainment and commercial services to diagnostic and safety tools. Mobility management has widely been recognized as one of the most challenging problems for seamless access to wireless networks. In this paper, a novel link enhancement mechanism is proposed to deal with mobility management problem in vehicular ad hoc networks. Two machine learning techniques, namely, particle swarm optimization and fuzzy logic systems, are incorporated into the proposed schemes to enhance the accuracy of prediction of link break and congestion occurrence. The experimental results verify the effectiveness and feasibility of the proposed schemes.

A Mobility-Aware Link Enhancement Mechanism for Vehicular Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Huang Chenn-Jung

2008-01-01

Full Text Available Abstract With the growth up of internet in mobile commerce, researchers have reproduced various mobile applications that vary from entertainment and commercial services to diagnostic and safety tools. Mobility management has widely been recognized as one of the most challenging problems for seamless access to wireless networks. In this paper, a novel link enhancement mechanism is proposed to deal with mobility management problem in vehicular ad hoc networks. Two machine learning techniques, namely, particle swarm optimization and fuzzy logic systems, are incorporated into the proposed schemes to enhance the accuracy of prediction of link break and congestion occurrence. The experimental results verify the effectiveness and feasibility of the proposed schemes.

Novel store–carry–forward scheme for message dissemination in vehicular ad-hoc networks

Directory of Open Access Journals (Sweden)

Truc D.T. Nguyen

2017-12-01

Full Text Available To improve traffic safety in intelligent transportation systems, vehicles formed by vehicular ad-hoc networks (VANETs conventionally disseminate warning messages to their nearby vehicles as soon as a dangerous situation occurs. In this paper, we propose a novel scheme employing a novel story–carry–forward (SCF mechanism to tackle the network partition and broadcast storm problems, which are two major challenges in VANETs. The experimental result in the Veins simulation framework shows that the proposed SCF scheme significantly mitigates broadcast storms relative to other schemes, and maintains good coverage across various traffic densities.

Ad hoc laser networks component technology for modular spacecraft

Science.gov (United States)

Huang, Xiujun; Shi, Dele; Shen, Jingshi

2017-10-01

Distributed reconfigurable satellite is a new kind of spacecraft system, which is based on a flexible platform of modularization and standardization. Based on the module data flow analysis of the spacecraft, this paper proposes a network component of ad hoc Laser networks architecture. Low speed control network with high speed load network of Microwave-Laser communication mode, no mesh network mode, to improve the flexibility of the network. Ad hoc Laser networks component technology was developed, and carried out the related performance testing and experiment. The results showed that ad hoc Laser networks components can meet the demand of future networking between the module of spacecraft.

Scientific Opinion on the substantiation of a health claim related to “L-tug lycopene” and reduction of blood LDL-cholesterol pursuant to Article 14 of Regulation (EC) No 1924/2006

DEFF Research Database (Denmark)

Tetens, Inge

2015-01-01

claim related to “L-tug lycopene” and reduction of blood low-density lipoprotein (LDL)-cholesterol. The food constituent that is the subject of the claim is L-tug lycopene (i.e. Lyc-O-Mato® embedded in fat-rich matrices by a manufacturing process claimed as proprietary and confidential by the applicant......). The Panel considers that the food constituent, L-tug lycopene, which is the subject of the claim, is sufficiently characterised. The Panel considers that reduction of blood LDL-cholesterol concentrations is a beneficial physiological effect. A reduction in blood LDL-cholesterol concentrations reduces...... the risk of CHD. The Panel notes that the unpublished studies submitted to support the claim were exploratory in nature and insufficient information was provided to allow the scientific evaluation of these studies. The Panel concludes that a cause and effect relationship has not been established between...

Tug-of-war between classical and multicenter bonds in H-(Be)n-H species

Science.gov (United States)

Lundell, Katie A.; Boldyrev, Alexander I.

2018-05-01

Quantum chemical calculations were performed for beryllium homocatenated compounds [H-(Be)n-H]. Global minimum structures were found using machine searches (Coalescence Kick method) with density functional theory. Chemical bonding analysis was performed with the Adaptive Natural Density Partitioning method. It was found that H-(Be)2-H and H-(Be)3-H clusters are linear with classical two-center two-electron bonds, while for n > 3, three-dimensional structures are more stable with multicenter bonding. Thus, at n = 4, multicenter bonding wins the tug-of-war vs. the classical bonding.

AD HOC Networks for the Autonomous Car

Science.gov (United States)

Ron, Davidescu; Negrus, Eugen

2017-10-01

The future of the vehicle is made of cars, roads and infrastructures connected in a two way automated communication in a holistic system. It is a mandatory to use Encryption to maintain Confidentiality, Integrity and Availability in an ad hoc vehicle network. Vehicle to Vehicle communication, requires multichannel interaction between mobile, moving and changing parties to insure the full benefit from data sharing and real time decision making, a network of such users referred as mobile ad hoc network (MANET), however as ad hoc networks were not implemented in such a scale, it is not clear what is the best method and protocol to apply. Furthermore the visibility of secure preferred asymmetric encrypted ad hoc networks in a real time environment of dense moving autonomous vehicles has to be demonstrated, In order to evaluate the performance of Ad Hoc networks in changing conditions a simulation of multiple protocols was performed on large number of mobile nodes. The following common routing protocols were tested, DSDV is a proactive protocol, every mobile station maintains a routing table with all available destinations, DSR is a reactive routing protocol which allows nodes in the MANET to dynamically discover a source route across multiple network hops, AODV is a reactive routing protocol Instead of being proactive. It minimizes the number of broadcasts by creating routes based on demand, SAODV is a secure version of AODV, requires heavyweight asymmetric cryptographic, ARIANDE is a routing protocol that relies on highly efficient symmetric cryptography the concept is primarily based on DSR. A methodical evolution was performed in a various density of transportation, based on known communication bench mark parameters including, Throughput Vs. time, Routing Load per packets and bytes. Out of the none encrypted protocols, It is clear that in terms of performance of throughput and routing load DSR protocol has a clear advantage the high node number mode. The encrypted

Validation test case generation based on safety analysis ontology

International Nuclear Information System (INIS)

Fan, Chin-Feng; Wang, Wen-Shing

2012-01-01

Highlights: ► Current practice in validation test case generation for nuclear system is mainly ad hoc. ► This study designs a systematic approach to generate validation test cases from a Safety Analysis Report. ► It is based on a domain-specific ontology. ► Test coverage criteria have been defined and satisfied. ► A computerized toolset has been implemented to assist the proposed approach. - Abstract: Validation tests in the current nuclear industry practice are typically performed in an ad hoc fashion. This study presents a systematic and objective method of generating validation test cases from a Safety Analysis Report (SAR). A domain-specific ontology was designed and used to mark up a SAR; relevant information was then extracted from the marked-up document for use in automatically generating validation test cases that satisfy the proposed test coverage criteria; namely, single parameter coverage, use case coverage, abnormal condition coverage, and scenario coverage. The novelty of this technique is its systematic rather than ad hoc test case generation from a SAR to achieve high test coverage.

Nuclear power plant safety

International Nuclear Information System (INIS)

Otway, H.J.

1974-01-01

Action at the international level will assume greater importance as the number of nuclear power plants increases, especially in the more densely populated parts of the world. Predictions of growth made prior to October 1973 [9] indicated that, by 1980, 14% of the electricity would be supplied by nuclear plants and by the year 2000 this figure would be about 50%. This will make the topic of international co-operation and standards of even greater importance. The IAEA has long been active in providing assistance to Member States in the siting design and operation of nuclear reactors. These activities have been pursued through advisory missions, the publication of codes of practice, guide books, technical reports and in arranging meetings to promote information exchange. During the early development of nuclear power, there was no well-established body of experience which would allow formulation of internationally acceptable safety criteria, except in a few special cases. Hence, nuclear power plant safety and reliability matters often received an ad hoc approach which necessarily entailed a lack of consistency in the criteria used and in the levels of safety required. It is clear that the continuation of an ad hoc approach to safety will prove inadequate in the context of a world-wide nuclear power industry, and the international trade which this implies. As in several other fields, the establishment of internationally acceptable safety standards and appropriate guides for use by regulatory bodies, utilities, designers and constructors, is becoming a necessity. The IAEA is presently planning the development of a comprehensive set of basic requirements for nuclear power plant safety, and the associated reliability requirements, which would be internationally acceptable, and could serve as a standard frame of reference for nuclear plant safety and reliability analyses

agradecimento aos consultores ad hoc

Directory of Open Access Journals (Sweden)

REA Editor

2012-02-01

Full Text Available Agradecemos aos professores Nildo Viana (UFG e Flavio Sofiati (UFG, organizadores do DOSSIÊ JUVENTUDE & SOCIEDADE, e aos Consultores Ad hoc pela leitura e apreciação crítica dos artigos submetidos e publicados nesta edição.

Performance Analysis of the IEEE 802.11p Multichannel MAC Protocol in Vehicular Ad Hoc Networks.

Science.gov (United States)

Song, Caixia

2017-12-12

Vehicular Ad Hoc Networks (VANETs) employ multichannel to provide a variety of safety and non-safety applications, based on the IEEE 802.11p and IEEE 1609.4 protocols. The safety applications require timely and reliable transmissions, while the non-safety applications require efficient and high throughput. In the IEEE 1609.4 protocol, operating interval is divided into alternating Control Channel (CCH) interval and Service Channel (SCH) interval with an identical length. During the CCH interval, nodes transmit safety-related messages and control messages, and Enhanced Distributed Channel Access (EDCA) mechanism is employed to allow four Access Categories (ACs) within a station with different priorities according to their criticality for the vehicle's safety. During the SCH interval, the non-safety massages are transmitted. An analytical model is proposed in this paper to evaluate performance, reliability and efficiency of the IEEE 802.11p and IEEE 1609.4 protocols. The proposed model improves the existing work by taking serval aspects and the character of multichannel switching into design consideration. Extensive performance evaluations based on analysis and simulation help to validate the accuracy of the proposed model and analyze the capabilities and limitations of the IEEE 802.11p and IEEE 1609.4 protocols, and enhancement suggestions are given.

Ad hoc networks telecommunications and game theory

CERN Document Server

Benslama, Malek; Batatia, Hadj

2015-01-01

Random SALOHA and CSMA protocols that are used to access MAC in ad hoc networks are very small compared to the multiple and spontaneous use of the transmission channel. So they have low immunity to the problems of packet collisions. Indeed, the transmission time is the critical factor in the operation of such networks. The simulations demonstrate the positive impact of erasure codes on the throughput of the transmission in ad hoc networks. However, the network still suffers from the intermittency and volatility of its efficiency throughout its operation, and it switches quickly to the satura

Vehicular ad hoc network security and privacy

CERN Document Server

Lin, X

2015-01-01

Unlike any other book in this area, this book provides innovative solutions to security issues, making this book a must read for anyone working with or studying security measures. Vehicular Ad Hoc Network Security and Privacy mainly focuses on security and privacy issues related to vehicular communication systems. It begins with a comprehensive introduction to vehicular ad hoc network and its unique security threats and privacy concerns and then illustrates how to address those challenges in highly dynamic and large size wireless network environments from multiple perspectives. This book is richly illustrated with detailed designs and results for approaching security and privacy threats.

Optimal channel choice for collaborative ad-hoc dissemination

DEFF Research Database (Denmark)

Hu, Liang; Boudec, J-Y. L.; Vojnovic, M.

2010-01-01

Collaborative ad-hoc dissemination of information has been proposed as an efficient means to disseminate information among devices in a wireless ad-hoc network. Devices help in forwarding the information channels to the entire network, by disseminating the channels they subscribe to, plus others...... by a Metropolis-Hastings sampling algorithm. We also give a variant that accounts for battery level. This leads to a practical channel selection and re-selection algorithm that can be implemented without any central control....

Les Protocoles de routage dans les réseaux mobiles Ad Hoc ...

African Journals Online (AJOL)

Dans cet article nous présentons un état de l'art sur les protocoles de routage dans les réseaux mobiles Ad hoc. Mots clés : Réseaux mobiles ad hoc/, Protocoles de routage. Routing protocols in wireless mobile ad hoc networks. Abstract:The communication between users with handheld computers interconnected through ...

Recreating the seawater mixture composition of HOCs in toxicity tests with Artemia franciscana by passive dosing

Energy Technology Data Exchange (ETDEWEB)

Rojo-Nieto, E., E-mail: elisa.rojo@uca.es [Andalusian Centre of Marine Science and Technology (CACYTMAR), Department of Environmental Technologies, University of Cadiz, 11510 Puerto Real (Spain); Smith, K.E.C. [Department of Environmental Science, Aarhus University, DK-4000 Roskilde (Denmark); Perales, J.A. [Andalusian Centre of Marine Science and Technology (CACYTMAR), Department of Environmental Technologies, University of Cadiz, 11510 Puerto Real (Spain); Mayer, P. [Department of Environmental Science, Aarhus University, DK-4000 Roskilde (Denmark)

2012-09-15

The toxicity testing of hydrophobic organic compounds (HOCs) in aquatic media is generally challenging, and this is even more problematic for mixtures. The hydrophobic properties of these compounds make them difficult to dissolve, and subsequently to maintain constant exposure concentrations. Evaporative and sorptive losses are highly compound-specific, which can alter not only total concentrations, but also the proportions between the compounds in the mixture. Therefore, the general aim of this study was to explore the potential of passive dosing for testing the toxicity of a PAH mixture that recreates the mixture composition found in seawater from a coastal area of Spain, the Bay of Algeciras. First, solvent spiking and passive dosing were compared for their suitability to determine the acute toxicity to Artemia franciscana nauplii of several PAHs at their respective solubility limits. Second, passive dosing was applied to recreate the seawater mixture composition of PAHs measured in a Spanish monitoring program, to test the toxicity of this mixture at different levels. HPLC analysis was used to confirm the reproducibility of the dissolved exposure concentrations for the individual PAHs and mixtures. This study shows that passive dosing has some important benefits in comparison with solvent spiking for testing HOCs in aquatic media. These include maintaining constant exposure concentrations, leading to higher reproducibility and a relative increase in toxicity. Passive dosing is also able to faithfully reproduce real mixtures of HOCs such as PAHs, in toxicity tests, reproducing both the levels and proportions of the different compounds. This provides a useful approach for studying the toxicity of environmental mixtures of HOCs, both with a view to investigating their toxicity but also for determining safety factors before such mixtures result in detrimental effects.

Auto-Configuration Protocols in Mobile Ad Hoc Networks

Science.gov (United States)

Villalba, Luis Javier García; Matesanz, Julián García; Orozco, Ana Lucila Sandoval; Díaz, José Duván Márquez

2011-01-01

The TCP/IP protocol allows the different nodes in a network to communicate by associating a different IP address to each node. In wired or wireless networks with infrastructure, we have a server or node acting as such which correctly assigns IP addresses, but in mobile ad hoc networks there is no such centralized entity capable of carrying out this function. Therefore, a protocol is needed to perform the network configuration automatically and in a dynamic way, which will use all nodes in the network (or part thereof) as if they were servers that manage IP addresses. This article reviews the major proposed auto-configuration protocols for mobile ad hoc networks, with particular emphasis on one of the most recent: D2HCP. This work also includes a comparison of auto-configuration protocols for mobile ad hoc networks by specifying the most relevant metrics, such as a guarantee of uniqueness, overhead, latency, dependency on the routing protocol and uniformity. PMID:22163814

Auto-configuration protocols in mobile ad hoc networks.

Science.gov (United States)

Villalba, Luis Javier García; Matesanz, Julián García; Orozco, Ana Lucila Sandoval; Díaz, José Duván Márquez

2011-01-01

The TCP/IP protocol allows the different nodes in a network to communicate by associating a different IP address to each node. In wired or wireless networks with infrastructure, we have a server or node acting as such which correctly assigns IP addresses, but in mobile ad hoc networks there is no such centralized entity capable of carrying out this function. Therefore, a protocol is needed to perform the network configuration automatically and in a dynamic way, which will use all nodes in the network (or part thereof) as if they were servers that manage IP addresses. This article reviews the major proposed auto-configuration protocols for mobile ad hoc networks, with particular emphasis on one of the most recent: D2HCP. This work also includes a comparison of auto-configuration protocols for mobile ad hoc networks by specifying the most relevant metrics, such as a guarantee of uniqueness, overhead, latency, dependency on the routing protocol and uniformity.

SURVEI TEKNIK CLUSTERING ROUTING BERDASARKAN MOBILITAS PADA WIRELESS AD-HOC NETWORK

Directory of Open Access Journals (Sweden)

I Nyoman Trisna Wirawan

2016-01-01

Full Text Available Wireless ad-hoc merupakan sebuah skema jaringan yang didesain supaya mampu beroperasi tanpa membutuhkan infrastruktur tetap serta bersifat otonom. Teknik flooding pada proses path discovery dalam kasus wireless ad-hoc network dapat menimbulkan masalah beban jaringan yang berlebihan. Oleh karena itu, sebuah skema clustering diusulkan untuk mengurangi adanya flooding paket yang berlebihan dengan membagi node-node dalam jaringan menjadi beberapa bagian berdasarkan parameter tertentu. Teknik ini efektifuntuk mengurangi paket yang harus dilewatkan dalam jaringan. Namun masalah muncul ketika sebuah jaringan wireless ad-hoc harus membentuk sebuah cluster dengan mempertimbangkan beberapa parameter khusus. Parameter tersebut harus disesuaikan dengan kasus yang dihadapi. Pada tulisan ini akan dibahas secara khusus mengenai penerapan skema clustering dalam lingkungan wireless ad-hoc network, baik pada MANETdan penyesuaian skema clustering yang harus dilakukan pada VANET berdasarkan mobilitasnya.

Effects of Data Replication on Data Exfiltration in Mobile Ad Hoc Networks Utilizing Reactive Protocols

Science.gov (United States)

2015-03-01

aerial vehicle VANET vehicular ad hoc network VoIP Voice over Internet Protocol VRR Virtual Ring Routing xiii EFFECTS OF DATA REPLICATION ON DATA...ad hoc networks in mobile ad hoc networks (MANETs), vehicular ad hoc networks (VANETs), and flying ad hoc net- works (FANETs). Much of the research...metric, such as capacity, congestion , power, or combinations thereof. Caro refers to two different types of ants, FANTs and BANTs which are analogous to

Sensor and ad-hoc networks theoretical and algorithmic aspects

CERN Document Server

Makki, S Kami; Pissinou, Niki; Makki, Shamila; Karimi, Masoumeh; Makki, Kia

2008-01-01

This book brings together leading researchers and developers in the field of wireless sensor networks to explain the special problems and challenges of the algorithmic aspects of sensor and ad-hoc networks. The book also fosters communication not only between the different sensor and ad-hoc communities, but also between those communities and the distributed systems and information systems communities. The topics addressed pertain to the sensors and mobile environment.

Use of an Anti-Gravity Treadmill for Early Postoperative Rehabilitation After Total Knee Replacement: A Pilot Study to Determine Safety and Feasibility.

Science.gov (United States)

Bugbee, William D; Pulido, Pamela A; Goldberg, Timothy; D'Lima, Darryl D

2016-01-01

The objective was to determine the safety, feasibility, and effects of anti-gravity gait training on functional outcomes (Knee Injury and Osteoarthritis Outcome Score [KOOS], the Timed Up and Go test [TUG], Numerical Rating Scale [NRS] for pain) with the AlterG® Anti-Gravity Treadmill® device for total knee arthroplasty (TKA) rehabilitation. Subjects (N = 30) were randomized to land-based vs anti-gravity gait training over 4 weeks of physical therapy after TKA. Adverse events, complications, and therapist satisfaction were recorded. All patients completed rehabilitation protocols without adverse events. KOOS, TUG, and NRS scores improved in both groups with no significant differences between groups. For the AlterG group, Sports/Recreation and Quality of Life subscales of the KOOS had the most improvement. At the end of physical therapy, TUG and NRS pain scores improved from 14 seconds to 8 seconds and from 2.8 to 1.1, respectively. Subjectively, therapists reported 100% satisfaction with the AlterG. This initial pilot study demonstrated that the AlterG Anti-Gravity Treadmill device was safe and feasible. While functional outcomes improved over time with use of the anti-gravity gait training, further studies are needed to define the role of this device as an alternative or adjunct to established rehabilitation protocols.

Multichannel MAC Layer In Mobile Ad—Hoc Network

Science.gov (United States)

Logesh, K.; Rao, Samba Siva

2010-11-01

This paper we presented the design objectives and technical challenges in Multichannel MAC protocols in Mobile Ad-hoc Network. In IEEE 802.11 a/b/g standards allow use of multiple channels, only a single channel is popularly used, due to the lack of efficient protocols that enable use of Multiple Channels. Even though complex environments in ad hoc networks require a combined control of physical (PHY) and medium access control (MAC) layers resources in order to optimize performance. And also we discuss the characteristics of cross-layer frame and give a multichannel MAC approach.

Post hoc analysis of Japanese patients from the placebo-controlled PREVAIL trial of enzalutamide in patients with chemotherapy-naive, metastatic castration-resistant prostate cancer—updated results

Science.gov (United States)

Ueda, Takeshi

2017-01-01

Abstract A post hoc analysis of interim results from PREVAIL, a Phase III, double-blind, placebo-controlled trial of men with metastatic castration-resistant prostate cancer, demonstrated that the treatment effects, safety and pharmacokinetics of enzalutamide in Japanese patients were generally consistent with those of the overall population. A recent longer term analysis of PREVAIL demonstrated continued benefit of enzalutamide treatment over placebo. Here, we report results from a post hoc analysis of Japanese patients enrolled in PREVAIL at the prespecified number of deaths for the final analysis. In Japanese patients, enzalutamide reduced the risk of death by 35% (hazard ratio, 0.65; 95% confidence interval, 0.28–1.51) and the risk of investigator-assessed radiographic progression or death by 60% (hazard ratio, 0.40; 95% confidence interval, 0.18–0.90). These results show that treatment effects and safety in Japanese patients in the final analysis of PREVAIL continued to be generally consistent with those of the overall population. PMID:28003320

Does Ad Hoc Coronary Intervention Reduce Radiation Exposure? – Analysis of 568 Patients

Energy Technology Data Exchange (ETDEWEB)

Truffa, Márcio A. M., E-mail: marciotruffa@yahoo.com.br; Alves, Gustavo M.P.; Bernardi, Fernando; Esteves Filho, Antonio; Ribeiro, Expedito; Galon, Micheli Z.; Spadaro, André; Kajita, Luiz J.; Arrieta, Raul; Lemos, Pedro A. [Instituto do Coração - Hospital das Clínicas - Faculdade de Medicina da Universidade de São Paulo (USP), São Paulo, SP (Brazil)

2015-11-15

Advantages and disadvantages of ad hoc percutaneous coronary intervention have been described. However little is known about the radiation exposure of that procedure as compared with the staged intervention. To compare the radiation dose of the ad hoc percutaneous coronary intervention with that of the staged procedure The dose-area product and total Kerma were measured, and the doses of the diagnostic and therapeutic procedures were added. In addition, total fluoroscopic time and number of acquisitions were evaluated. A total of 568 consecutive patients were treated with ad hoc percutaneous coronary intervention (n = 320) or staged percutaneous coronary intervention (n = 248). On admission, the ad hoc group had less hypertension (74.1% vs 81.9%; p = 0.035), dyslipidemia (57.8% vs. 67.7%; p = 0.02) and three-vessel disease (38.8% vs. 50.4%; p = 0.015). The ad hoc group was exposed to significantly lower radiation doses, even after baseline characteristic adjustment between both groups. The ad hoc group was exposed to a total dose-area product of 119.7 ± 70.7 Gycm{sup 2}, while the staged group, to 139.2 ± 75.3 Gycm{sup 2} (p < 0.001). Ad hoc percutaneous coronary intervention reduced radiation exposure as compared with diagnostic and therapeutic procedures performed at two separate times.

Does Ad Hoc Coronary Intervention Reduce Radiation Exposure? – Analysis of 568 Patients

International Nuclear Information System (INIS)

Truffa, Márcio A. M.; Alves, Gustavo M.P.; Bernardi, Fernando; Esteves Filho, Antonio; Ribeiro, Expedito; Galon, Micheli Z.; Spadaro, André; Kajita, Luiz J.; Arrieta, Raul; Lemos, Pedro A.

2015-01-01

Advantages and disadvantages of ad hoc percutaneous coronary intervention have been described. However little is known about the radiation exposure of that procedure as compared with the staged intervention. To compare the radiation dose of the ad hoc percutaneous coronary intervention with that of the staged procedure The dose-area product and total Kerma were measured, and the doses of the diagnostic and therapeutic procedures were added. In addition, total fluoroscopic time and number of acquisitions were evaluated. A total of 568 consecutive patients were treated with ad hoc percutaneous coronary intervention (n = 320) or staged percutaneous coronary intervention (n = 248). On admission, the ad hoc group had less hypertension (74.1% vs 81.9%; p = 0.035), dyslipidemia (57.8% vs. 67.7%; p = 0.02) and three-vessel disease (38.8% vs. 50.4%; p = 0.015). The ad hoc group was exposed to significantly lower radiation doses, even after baseline characteristic adjustment between both groups. The ad hoc group was exposed to a total dose-area product of 119.7 ± 70.7 Gycm 2 , while the staged group, to 139.2 ± 75.3 Gycm 2 (p < 0.001). Ad hoc percutaneous coronary intervention reduced radiation exposure as compared with diagnostic and therapeutic procedures performed at two separate times

Analysis for Ad Hoc Network Attack-Defense Based on Stochastic Game Model

Directory of Open Access Journals (Sweden)

Yuanjie LI

2014-06-01

Full Text Available The attack actions analysis for Ad Hoc networks can provide a reference for the design security mechanisms. This paper presents an analysis method of security of Ad Hoc networks based on Stochastic Game Nets (SGN. This method can establish a SGN model of Ad Hoc networks and calculate to get the Nash equilibrium strategy. After transforming the SGN model into a continuous-time Markov Chain (CTMC, the security of Ad Hoc networks can be evaluated and analyzed quantitatively by calculating the stationary probability of CTMC. Finally, the Matlab simulation results show that the probability of successful attack is related to the attack intensity and expected payoffs, but not attack rate.

Securing DSR with mobile agents in wireless ad hoc networks

Directory of Open Access Journals (Sweden)

Ahmed Abosamra

2011-03-01

Full Text Available Ad hoc wireless network consists of a set of wireless nodes communicating with each other without a pre-defined infrastructure. They communicate by forwarding packets which can reach wireless nodes that do not exist in the range of the direct radio transmission. Designing ad hoc network routing protocols is a challenging task because of its decentralized infrastructure which makes securing ad hoc networks more and more challenging. Dynamic Source Routing (DSR protocol is a popular routing protocol designed for use in wireless ad hoc networks. Mobile agent is a promising technology used in diverse fields of network applications. In this paper, we try to implement DSR using mobile agents for securing this type of wireless network. Hybrid encryption technique (symmetric key encryption/public key encryption is used to improve performance; where symmetric keys are used to encrypt routing data to authenticate and authorize node sending data, while, public keys are used for the exchange of symmetric keys between nodes. We found that DSR may be secured using mobile agents with competitive performance.

Performance analysis and implementation of proposed mechanism for detection and prevention of security attacks in routing protocols of vehicular ad-hoc network (VANET

Directory of Open Access Journals (Sweden)

Parul Tyagi

2017-07-01

Full Text Available Next-generation communication networks have become widely popular as ad-hoc networks, broadly categorized as the mobile nodes based on mobile ad-hoc networks (MANET and the vehicular nodes based vehicular ad-hoc networks (VANET. VANET is aimed at maintaining safety to vehicle drivers by begin autonomous communication with the nearby vehicles. Each vehicle in the ad-hoc network performs as an intelligent mobile node characterized by high mobility and formation of dynamic networks. The ad-hoc networks are decentralized dynamic networks that need efficient and secure communication requirements due to the vehicles being persistently in motion. These networks are more susceptible to various attacks like Warm Hole attacks, denial of service attacks and Black Hole Attacks. The paper is a novel attempt to examine and investigate the security features of the routing protocols in VANET, applicability of AODV (Ad hoc On Demand protocol to detect and tackle a particular category of network attacks, known as the Black Hole Attacks. A new algorithm is proposed to enhance the security mechanism of AODV protocol and to introduce a mechanism to detect Black Hole Attacks and to prevent the network from such attacks in which source node stores all route replies in a look up table. This table stores the sequences of all route reply, arranged in ascending order using PUSH and POP operations. The priority is calculated based on sequence number and discard the RREP having presumably very high destination sequence number. The result show that proposed algorithm for detection and prevention of Black Hole Attack increases security in Intelligent Transportation System (ITS and reduces the effect of malicious node in the VANET. NCTUNs simulator is used in this research work.

Model checking mobile ad hoc networks

NARCIS (Netherlands)

Ghassemi, Fatemeh; Fokkink, Wan

2016-01-01

Modeling arbitrary connectivity changes within mobile ad hoc networks (MANETs) makes application of automated formal verification challenging. We use constrained labeled transition systems as a semantic model to represent mobility. To model check MANET protocols with respect to the underlying

MWAHCA: a multimedia wireless ad hoc cluster architecture.

Science.gov (United States)

Diaz, Juan R; Lloret, Jaime; Jimenez, Jose M; Sendra, Sandra

2014-01-01

Wireless Ad hoc networks provide a flexible and adaptable infrastructure to transport data over a great variety of environments. Recently, real-time audio and video data transmission has been increased due to the appearance of many multimedia applications. One of the major challenges is to ensure the quality of multimedia streams when they have passed through a wireless ad hoc network. It requires adapting the network architecture to the multimedia QoS requirements. In this paper we propose a new architecture to organize and manage cluster-based ad hoc networks in order to provide multimedia streams. Proposed architecture adapts the network wireless topology in order to improve the quality of audio and video transmissions. In order to achieve this goal, the architecture uses some information such as each node's capacity and the QoS parameters (bandwidth, delay, jitter, and packet loss). The architecture splits the network into clusters which are specialized in specific multimedia traffic. The real system performance study provided at the end of the paper will demonstrate the feasibility of the proposal.

MWAHCA: A Multimedia Wireless Ad Hoc Cluster Architecture

Directory of Open Access Journals (Sweden)

Juan R. Diaz

2014-01-01

Full Text Available Wireless Ad hoc networks provide a flexible and adaptable infrastructure to transport data over a great variety of environments. Recently, real-time audio and video data transmission has been increased due to the appearance of many multimedia applications. One of the major challenges is to ensure the quality of multimedia streams when they have passed through a wireless ad hoc network. It requires adapting the network architecture to the multimedia QoS requirements. In this paper we propose a new architecture to organize and manage cluster-based ad hoc networks in order to provide multimedia streams. Proposed architecture adapts the network wireless topology in order to improve the quality of audio and video transmissions. In order to achieve this goal, the architecture uses some information such as each node’s capacity and the QoS parameters (bandwidth, delay, jitter, and packet loss. The architecture splits the network into clusters which are specialized in specific multimedia traffic. The real system performance study provided at the end of the paper will demonstrate the feasibility of the proposal.

Algorithmic, LOCS and HOCS (chemistry) exam questions: performance and attitudes of college students

Science.gov (United States)

Zoller, Uri

2002-02-01

The performance of freshmen biology and physics-mathematics majors and chemistry majors as well as pre- and in-service chemistry teachers in two Israeli universities on algorithmic (ALG), lower-order cognitive skills (LOCS), and higher-order cognitive skills (HOCS) chemistry exam questions were studied. The driving force for the study was an interest in moving science and chemistry instruction from an algorithmic and factual recall orientation dominated by LOCS, to a decision-making, problem-solving and critical system thinking approach, dominated by HOCS. College students' responses to the specially designed ALG, LOCS and HOCS chemistry exam questions were scored and analysed for differences and correlation between the performance means within and across universities by the questions' category. This was followed by a combined student interview - 'speaking aloud' problem solving session for assessing the thinking processes involved in solving these types of questions and the students' attitudes towards them. The main findings were: (1) students in both universities performed consistently in each of the three categories in the order of ALG > LOCS > HOCS; their 'ideological' preference, was HOCS > algorithmic/LOCS, - referred to as 'computational questions', but their pragmatic preference was the reverse; (2) success on algorithmic/LOCS does not imply success on HOCS questions; algorithmic questions constitute a category on its own as far as students success in solving them is concerned. Our study and its results support the effort being made, worldwide, to integrate HOCS-fostering teaching and assessment strategies and, to develop HOCS-oriented science-technology-environment-society (STES)-type curricula within science and chemistry education.

Internet-Based Mobile Ad Hoc Networking (Preprint)

National Research Council Canada - National Science Library

Corson, M. S; Macker, Joseph P; Cirincione, Gregory H

1999-01-01

Internet-based Mobile Ad Hoc Networking is an emerging technology that supports self-organizing, mobile networking infrastructures, and is one which appears well-suited for use in future commercial...

A Clustering Routing Protocol for Mobile Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Jinke Huang

2016-01-01

Full Text Available The dynamic topology of a mobile ad hoc network poses a real challenge in the design of hierarchical routing protocol, which combines proactive with reactive routing protocols and takes advantages of both. And as an essential technique of hierarchical routing protocol, clustering of nodes provides an efficient method of establishing a hierarchical structure in mobile ad hoc networks. In this paper, we designed a novel clustering algorithm and a corresponding hierarchical routing protocol for large-scale mobile ad hoc networks. Each cluster is composed of a cluster head, several cluster gateway nodes, several cluster guest nodes, and other cluster members. The proposed routing protocol uses proactive protocol between nodes within individual clusters and reactive protocol between clusters. Simulation results show that the proposed clustering algorithm and hierarchical routing protocol provide superior performance with several advantages over existing clustering algorithm and routing protocol, respectively.

Multiagent Based Information Dissemination in Vehicular Ad Hoc Networks

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S.S. Manvi

2009-01-01

Full Text Available Vehicular Ad hoc Networks (VANETs are a compelling application of ad hoc networks, because of the potential to access specific context information (e.g. traffic conditions, service updates, route planning and deliver multimedia services (Voice over IP, in-car entertainment, instant messaging, etc.. This paper proposes an agent based information dissemination model for VANETs. A two-tier agent architecture is employed comprising of the following: 1 'lightweight', network-facing, mobile agents; 2 'heavyweight', application-facing, norm-aware agents. The limitations of VANETs lead us to consider a hybrid wireless network architecture that includes Wireless LAN/Cellular and ad hoc networking for analyzing the proposed model. The proposed model provides flexibility, adaptability and maintainability for traffic information dissemination in VANETs as well as supports robust and agile network management. The proposed model has been simulated in various network scenarios to evaluate the effectiveness of the approach.

Atomoxetine treatment outcomes in adolescents and young adults with attention-deficit/hyperactivity disorder: results from a post hoc, pooled analysis.

Science.gov (United States)

Adler, Lenard A; Wilens, Timothy; Zhang, Shuyu; Dittmann, Ralf W; D'Souza, Deborah N; Schuh, Leslie; Durell, Todd M

2012-02-01

Many children with attention-deficit/hyperactivity disorder (ADHD) continue to experience this disorder as adults, which may, in part, be due to the discontinuity of health care that often occurs during the transition period between late adolescence and young adulthood. Although atomoxetine is reported to be efficacious in both adolescents and young adults, no longitudinal studies have been designed to assess directly the effects of atomoxetine treatment during this transition period. As a first step, we present the results of a post hoc, pooled analysis that compared the efficacy and safety profile of atomoxetine in these 2 patient populations. The aim of the present study was to assess the efficacy and safety profile of atomoxetine treatment in adolescents and young adults with ADHD. A post hoc, pooled analysis was conducted by combining data from 6 double-blind trials (6-9 weeks in duration) that studied adolescents (12-17 years of age; atomoxetine, n = 154; placebo, n = 88; mean final dose = 1.38 mg/kg) and 3 trials (10 weeks in duration) that studied young adults (18-30 years of age; atomoxetine, n = 117; placebo, n = 125; mean final dose = 1.21 mg/kg). Efficacy measures used in these analyses were ADHD Rating Scale (ADHDRS) for adolescents, Conners' Adult ADHD Rating Scale (CAARS) for young adults, and Clinical Global Impressions-ADHD-Severity (CGI-ADHD-S) for both age groups. Treatment response was defined as ≥30% reduction from baseline in total ADHD symptom score. In adolescents (mean age, 13.4 years), atomoxetine improved ADHD significantly compared with placebo (ADHDRS total score change, -12.9 vs -7.5; P young adults (mean age, 24.7 years), atomoxetine improved ADHD significantly (CAARS total score change, -13.6 vs -7.7; P young adults (13.7% vs 4.8%, respectively; P = 0.024); in adolescents no statistically significant differences were observed in frequency of nausea between atomoxetine and placebo treatment (4.5% vs 10.2%, respectively; P = 0

Ad hoc supervision of general practice registrars as a 'community of practice': analysis, interpretation and re-presentation.

Science.gov (United States)

Clement, T; Brown, J; Morrison, J; Nestel, D

2016-05-01

General practice registrars in Australia undertake most of their vocational training in accredited general practices. They typically see patients alone from the start of their community-based training and are expected to seek timely ad hoc support from their supervisor. Such ad hoc encounters are a mechanism for ensuring patient safety, but also provide an opportunity for learning and teaching. Wenger's (Communities of practice: learning, meaning, and identity. Cambridge University Press, New York, 1998) social theory of learning ('communities of practice') guided a secondary analysis of audio-recordings of ad hoc encounters. Data from one encounter is re-presented as an extended sequence to maintain congruence with the theoretical perspective and enhance vicariousness. An interpretive commentary communicates key features of Wenger's theory and highlights the researchers' interpretations. We argue that one encounter can reveal universal understandings of clinical supervision and that the process of naturalistic generalisation allows readers to transfer others' experiences to their own contexts. The paper raises significant analytic, interpretive, and representational issues. We highlight that report writing is an important, but infrequently discussed, part of research design. We discuss the challenges of supporting the learning and teaching that arises from adopting a socio-cultural lens and argue that such a perspective importantly captures the complex range of issues that work-based practitioners have to grapple with. This offers a challenge to how we research and seek to influence work-based learning and teaching in health care settings.

TUG1, SPRY4-IT1, and HULC as valuable prognostic biomarkers of survival in cancer: A PRISMA-compliant meta-analysis.

Science.gov (United States)

Zhong, Yucheng; Chen, Zhicong; Guo, Shuyuan; Liao, Xinhui; Xie, Haibiao; Zheng, Yien; Cai, Bin; Huang, Peixian; Liu, Yuhan; Zhou, Qun; Liu, Yuchen; Huang, Weiren

2017-11-01

Long noncoding RNAs (LncRNAs) are involved in the development and progression of various cancers. Accumulating evidences indicated that expression of lncRNAs was related to the prognosis of tumors. Here, 3 well-known lncRNAs associated with cancer were gathered to prove the potential role of lncRNAs as novel predictors of survival in human cancer. This meta-analysis collected all eligible studies about TUG1, SPRY4-IT1, and HULC and explored the relationship between lncRNAs expression and lymph node metastasis (LNM) or overall survival (OS). A comprehensive, computerized literature search was undertaken by using PubMed, EMBASE, Cochrane Library, and Web of Science (up to October 10, 2017). Strength of association between 3 lncRNAs and cancer prognosis was assessed by computing the hazard ratios (HR) with its corresponding 95% confidence interval (CI). According to the inclusion and exclusion criteria, respectively, 10, 9, and 7 studies of 3 lncRNAs were included in this meta-analysis. In the current meta-analysis, it could be concluded that the expression of these 3 lncRNAs in tumor tissues is not a direct evidence of LNM. In general, there was a significant negative correlation between TUG1 levels and OS time (pooled HR 1.54, 95% CI 1.06-2.24), SPRY4-IT1 levels and OS time (pooled HR 2.12, 95% CI 1.58-2.86) and HULC levels and OS time (pooled HR 2.10, 95% CI 1.18-3.73). It could be revealed from the result that high level expression of these 3 lncRNAs might be correlated with a bad prognosis. In conclusion, the current meta-analysis demonstrated that TUG1, SPRY4-IT1, and HULC might serve as a moderate predictor of survival in human cancer.

DESAIN ALGORITMA DAN SIMULASI ROUTING UNTUK GATEWAY AD HOC WIRELESS NETWORKS

Directory of Open Access Journals (Sweden)

Nixson Meok

2009-12-01

Full Text Available   Routing protocol to the wireless ad hoc networks is very needed in the communication process between some terminals, to send the data packet through one or several node(s to the destination address where the network typology is always changing. Many previous works that discussed about routing ad hoc both for manet (mobile ad hoc networks and wireless networks, but the emphasis have more focus on comparing the performance of several routing ad hoc. While in this work, there is a bulding of routing algorithm model to gateway in land to the nodes that analogized as a boat that move on the sea. With the assumption that the communication inter terminals to radio band of Very High Frequency, thus algorithm that built in the simulation based on the range gap of the HF frequency. The result of this simulation will be developed as the platform to implement the service development of multiuser communication

Student Self-Assessment in HOCS Science Examinations: Is There a Problem?

Science.gov (United States)

Zoller, Uri; Ben-Chaim, David

1998-06-01

A specially-designed self-assessment questionnaire (SAQHOCS), containing higher-order cognitive skills (HOCS)-type questions, was administered to 71 biology majors, enrolled in a four-year college program. The gap between students' self-assessment marking, and that of their HOCS-biased teachers (the authors), is accounted for by the prevailing LOCS-orientation and the "testing culture"—a total separation between testing and learning—in contemporary science teaching. The majority of the students in the study evaluated themselves as capable of self-assessment, and felt reasonably confident in doing so. They were quite reserved as far as the applicability of the self-assessment method to nonalgorithmic ("correct/incorrect") questions is concerned. The results of this study suggest that the potential for student self-assessment within college science teaching and learning exists. However, still a great purposed effort in HOCS-oriented teaching and learning is required in order for the student self-assessment practice to become a routine integral component of HOCS science examinations.

Quantum load balancing in ad hoc networks

Science.gov (United States)

Hasanpour, M.; Shariat, S.; Barnaghi, P.; Hoseinitabatabaei, S. A.; Vahid, S.; Tafazolli, R.

2017-06-01

This paper presents a novel approach in targeting load balancing in ad hoc networks utilizing the properties of quantum game theory. This approach benefits from the instantaneous and information-less capability of entangled particles to synchronize the load balancing strategies in ad hoc networks. The quantum load balancing (QLB) algorithm proposed by this work is implemented on top of OLSR as the baseline routing protocol; its performance is analyzed against the baseline OLSR, and considerable gain is reported regarding some of the main QoS metrics such as delay and jitter. Furthermore, it is shown that QLB algorithm supports a solid stability gain in terms of throughput which stands a proof of concept for the load balancing properties of the proposed theory.

Recent development in wireless sensor and ad-hoc networks

CERN Document Server

Li, Xiaolong; Yang, Yeon-Mo

2015-01-01

Wireless Sensor Network (WSN) consists of numerous physically distributed autonomous devices used for sensing and monitoring the physical and/or environmental conditions. A WSN uses a gateway that provides wireless connectivity to the wired world as well as distributed networks. There are many open problems related to Ad-Hoc networks and its applications. Looking at the expansion of the cellular infrastructure, Ad-Hoc network may be acting as the basis of the 4th generation wireless technology with the new paradigm of ‘anytime, anywhere communications’. To realize this, the real challenge would be the security, authorization and management issues of the large scale WSNs. This book is an edited volume in the broad area of WSNs. The book covers various chapters like Multi-Channel Wireless Sensor Networks, its Coverage, Connectivity as well as Deployment. It covers comparison of various communication protocols and algorithms such as MANNET, ODMRP and ADMR Protocols for Ad hoc Multicasting, Location Based C...

A flow level model for wireless multihop ad hoc network throughput

NARCIS (Netherlands)

Coenen, Tom Johannes Maria; van den Berg, Hans Leo; Boucherie, Richardus J.

2005-01-01

A flow level model for multihop wireless ad hoc networks is presented in this paper. Using a flow level view, we show the main properties and modeling challenges for ad hoc networks. Considering different scenarios, a multihop WLAN and a serial network with a TCP-like flow control protocol, we

Energy-Aware Routing Protocol for Ad Hoc Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Mann Raminder P

2005-01-01

Full Text Available Wireless ad hoc sensor networks differ from wireless ad hoc networks from the following perspectives: low energy, lightweight routing protocols, and adaptive communication patterns. This paper proposes an energy-aware routing protocol (EARP suitable for ad hoc wireless sensor networks and presents an analysis for its energy consumption in various phases of route discovery and maintenance. Based on the energy consumption associated with route request processing, EARP advocates the minimization of route requests by allocating dynamic route expiry times. This paper introduces a unique mechanism for estimation of route expiry time based on the probability of route validity, which is a function of time, number of hops, and mobility parameters. In contrast to AODV, EARP reduces the repeated flooding of route requests by maintaining valid routes for longer durations.

Supporting Dynamic Ad hoc Collaboration Capabilities

CERN Document Server

Agarwal, D

2003-01-01

Modern HENP experiments such as CMS and Atlas involve as many as 2000 collaborators around the world. Collaborations this large will be unable to meet often enough to support working closely together. Many of the tools currently available for collaboration focus on heavy-weight applications such as videoconferencing tools. While these are important, there is a more basic need for tools that support connecting physicists to work together on an ad hoc or continuous basis. Tools that support the day-to-day connectivity and underlying needs of a group of collaborators are important for providing light-weight, non-intrusive, and flexible ways to work collaboratively. Some example tools include messaging, file-sharing, and shared plot viewers. An important component of the environment is a scalable underlying communication framework. In this paper we will describe our current progress on building a dynamic and ad hoc collaboration environment and our vision for its evolution into a HENP collaboration environment.

Supporting Dynamic Ad hoc Collaboration Capabilities

International Nuclear Information System (INIS)

Agarwal, Deborah A.; Berket, Karlo

2003-01-01

Modern HENP experiments such as CMS and Atlas involve as many as 2000 collaborators around the world. Collaborations this large will be unable to meet often enough to support working closely together. Many of the tools currently available for collaboration focus on heavy-weight applications such as videoconferencing tools. While these are important, there is a more basic need for tools that support connecting physicists to work together on an ad hoc or continuous basis. Tools that support the day-to-day connectivity and underlying needs of a group of collaborators are important for providing light-weight, non-intrusive, and flexible ways to work collaboratively. Some example tools include messaging, file-sharing, and shared plot viewers. An important component of the environment is a scalable underlying communication framework. In this paper we will describe our current progress on building a dynamic and ad hoc collaboration environment and our vision for its evolution into a HENP collaboration environment

Effect of Concomitant Medications on the Safety and Efficacy of Extended-Release Carbidopa-Levodopa (IPX066) in Patients With Advanced Parkinson Disease: A Post Hoc Analysis.

Science.gov (United States)

LeWitt, Peter A; Verhagen Metman, Leo; Rubens, Robert; Khanna, Sarita; Kell, Sherron; Gupta, Suneel

Extended-release (ER) carbidopa-levodopa (CD-LD) (IPX066/RYTARY/NUMIENT) produces improvements in "off" time, "on" time without troublesome dyskinesia, and Unified Parkinson Disease Rating Scale scores compared with immediate-release (IR) CD-LD or IR CD-LD plus entacapone (CLE). Post hoc analyses of 2 ER CD-LD phase 3 trials evaluated whether the efficacy and safety of ER CD-LD relative to the respective active comparators were altered by concomitant medications (dopaminergic agonists, monoamine oxidase B [MAO-B] inhibitors, or amantadine). ADVANCE-PD (n = 393) assessed safety and efficacy of ER CD-LD versus IR CD-LD. ASCEND-PD (n = 91) evaluated ER CD-LD versus CLE. In both studies, IR- and CLE-experienced patients underwent a 6-week, open-label dose-conversion period to ER CD-LD prior to randomization. For analysis, the randomized population was divided into 3 subgroups: dopaminergic agonists, rasagiline or selegiline, and amantadine. For each subgroup, changes from baseline in PD diary measures ("off" time and "on" time with and without troublesome dyskinesia), Unified Parkinson Disease Rating Scale Parts II + III scores, and adverse events were analyzed, comparing ER CD-LD with the active comparator. Concomitant dopaminergic agonist or MAO-B inhibitor use did not diminish the efficacy (improvement in "off" time and "on" time without troublesome dyskinesia) of ER CD-LD compared with IR CD-LD or CLE, whereas the improvement with concomitant amantadine failed to reach significance. Safety and tolerability were similar among the subgroups, and ER CD-LD did not increase troublesome dyskinesia. For patients on oral LD regimens and taking a dopaminergic agonist, and/or a MAO-B inhibitor, changing from an IR to an ER CD-LD formulation provides approximately an additional hour of "good" on time.

Twenty-One at TREC-7: ad-hoc and cross-language track

NARCIS (Netherlands)

Hiemstra, Djoerd; Kraaij, Wessel; Voorhees, E.M; Harman, D.K.

1999-01-01

This paper describes the official runs of the Twenty-One group for TREC-7. The Twenty-One group participated in the ad-hoc and the cross-language track and made the following accomplishments: We developed a new weighting algorithm, which outperforms the popular Cornell version of BM25 on the ad-hoc

Once-monthly injection of paliperidone palmitate in patients with recently diagnosed and chronic schizophrenia: a post-hoc comparison of efficacy and safety.

Science.gov (United States)

Si, Tianmei; Zhuo, Jianmin; Turkoz, Ibrahim; Mathews, Maju; Tan, Wilson; Feng, Yu

2017-12-01

The use of long-acting injectable antipsychotics in recently diagnosed schizophrenia remains less explored. We evaluated the efficacy and safety of paliperidone palmitate once-monthly (PP1M) treatment in adult patients with recently diagnosed vs. chronic schizophrenia. These post-hoc analyses included two multicenter studies. Study 1 (NCT01527305) enrolled recently diagnosed (≤5 years) and chronic (>5 years) patients; Study 2 (NCT01051531) enrolled recently diagnosed patients only. Recently diagnosed patients were further sub-grouped into ≤2 years or 2-5 years. The primary efficacy endpoint was the change from baseline in Positive and Negative Syndrome Scale (PANSS) total score. In Study 1, 41.5% patients had recent diagnosis (≤2 years: 56.8%; 2-5 years: 43.2%); 58.5% had chronic schizophrenia. In Study 2, 52.8% and 47.2% patients were grouped into ≤2 years and 2-5 years, respectively. PANSS total score showed significantly greater improvement in patients with recently diagnosed vs. chronic schizophrenia. Similar results were obtained for PANSS responder rate, improvements in PANSS, and CGI-S scores. PP1M was efficacious in both recently diagnosed and chronic schizophrenia, with the benefits being more pronounced in patients with recently diagnosed schizophrenia. This adds to growing evidence recommending long-acting antipsychotic interventions at early stages of schizophrenia.

NDN-CRAHNs: Named Data Networking for Cognitive Radio Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Rana Asif Rehman

2015-01-01

Full Text Available Named data networking (NDN is a newly proposed paradigm for future Internet, in which communication among nodes is based on data names, decoupling from their locations. In dynamic and self-organized cognitive radio ad hoc networks (CRAHNs, it is difficult to maintain end-to-end connectivity between ad hoc nodes especially in the presence of licensed users and intermittent wireless channels. Moreover, IP-based CRAHNs have several issues like scalability, inefficient-mapping, poor resource utilization, and location dependence. By leveraging the advantages of NDN, in this paper, we propose a new cross layer fine-grained architecture called named data networking for cognitive radio ad hoc networks (NDN-CRAHNs. The proposed architecture provides distinct features such as in-networking caching, security, scalability, and multipath routing. The performances of the proposed scheme are evaluated comparing to IP-based scheme in terms of average end-to-end delay and packet delivery ratio. Simulation results show that the proposed scheme is effective in terms of average contents download time and packet delivery ratios comparing to conventional cognitive radio ad hoc networks.

Packets Distributing Evolutionary Algorithm Based on PSO for Ad Hoc Network

Science.gov (United States)

Xu, Xiao-Feng

2018-03-01

Wireless communication network has such features as limited bandwidth, changeful channel and dynamic topology, etc. Ad hoc network has lots of difficulties in accessing control, bandwidth distribution, resource assign and congestion control. Therefore, a wireless packets distributing Evolutionary algorithm based on PSO (DPSO)for Ad Hoc Network is proposed. Firstly, parameters impact on performance of network are analyzed and researched to obtain network performance effective function. Secondly, the improved PSO Evolutionary Algorithm is used to solve the optimization problem from local to global in the process of network packets distributing. The simulation results show that the algorithm can ensure fairness and timeliness of network transmission, as well as improve ad hoc network resource integrated utilization efficiency.

A Framework for Speech Enhancement with Ad Hoc Microphone Arrays

DEFF Research Database (Denmark)

Tavakoli, Vincent Mohammad; Jensen, Jesper Rindom; Christensen, Mads Græsbøll

2016-01-01

Speech enhancement is vital for improved listening practices. Ad hoc microphone arrays are promising assets for this purpose. Most well-established enhancement techniques with conventional arrays can be adapted into ad hoc scenarios. Despite recent efforts to introduce various ad hoc speech...... enhancement apparatus, a common framework for integration of conventional methods into this new scheme is still missing. This paper establishes such an abstraction based on inter and intra sub-array speech coherencies. Along with measures for signal quality at the input of sub-arrays, a measure of coherency...... is proposed both for sub-array selection in local enhancement approaches, and also for selecting a proper global reference when more than one sub-array are used. Proposed methods within this framework are evaluated with regard to quantitative and qualitative measures, including array gains, the speech...

Post hoc analysis of Japanese patients from the placebo-controlled PREVAIL trial of enzalutamide in patients with chemotherapy-naive, metastatic castration-resistant prostate cancer-updated results.

Science.gov (United States)

Kimura, Go; Ueda, Takeshi

2017-03-01

A post hoc analysis of interim results from PREVAIL, a Phase III, double-blind, placebo-controlled trial of men with metastatic castration-resistant prostate cancer, demonstrated that the treatment effects, safety and pharmacokinetics of enzalutamide in Japanese patients were generally consistent with those of the overall population. A recent longer term analysis of PREVAIL demonstrated continued benefit of enzalutamide treatment over placebo. Here, we report results from a post hoc analysis of Japanese patients enrolled in PREVAIL at the prespecified number of deaths for the final analysis. In Japanese patients, enzalutamide reduced the risk of death by 35% (hazard ratio, 0.65; 95% confidence interval, 0.28-1.51) and the risk of investigator-assessed radiographic progression or death by 60% (hazard ratio, 0.40; 95% confidence interval, 0.18-0.90). These results show that treatment effects and safety in Japanese patients in the final analysis of PREVAIL continued to be generally consistent with those of the overall population. © The Author 2016. Published by Oxford University Press.

SVANET: A smart vehicular ad hoc network for efficient data transmission with wireless sensors.

Science.gov (United States)

Sahoo, Prasan Kumar; Chiang, Ming-Jer; Wu, Shih-Lin

2014-11-25

Wireless sensors can sense any event, such as accidents, as well as icy roads, and can forward the rescue/warning messages through intermediate vehicles for any necessary help. In this paper, we propose a smart vehicular ad hoc network (SVANET) architecture that uses wireless sensors to detect events and vehicles to transmit the safety and non-safety messages efficiently by using different service channels and one control channel with different priorities. We have developed a data transmission protocol for the vehicles in the highway, in which data can be forwarded with the help of vehicles if they are connected with each other or data can be forwarded with the help of nearby wireless sensors. Our data transmission protocol is designed to increase the driving safety, to prevent accidents and to utilize channels efficiently by adjusting the control and service channel time intervals dynamically. Besides, our protocol can transmit information to vehicles in advance, so that drivers can decide an alternate route in case of traffic congestion. For various data sharing, we design a method that can select a few leader nodes among vehicles running along a highway to broadcast data efficiently. Simulation results show that our protocol can outperform the existing standard in terms of the end to end packet delivery ratio and latency.

Handbook on theoretical and algorithmic aspects of sensor, ad hoc wireless, and peer-to-peer networks

CERN Document Server

Wu, Jie

2005-01-01

PrefaceAD HOC WIRELESS NETWORKSA Modular Cross Layer Architecture for Ad Hoc Networks, M. Conti, J. Crowcroft, G. Maselli, and G. TuriRouting Scalability in MANETs, J. Eriksson, S. Krishnamurthy and M. FaloutsosUniformly Distributed Algorithm for Virtual Backbone Routing in Ad Hoc Wireless Networks, D.S. KimMaximum Necessary Hop Count for Packet Routing in MANET, X. Chen and J. ShenEfficient Strategyproof Multicast in Selfish Wireless Networks, X.-Yang LiGeocasting in Ad Hoc and Sensor Networks, I. StojmenovicTopology Control for Ad hoc Networks: Present Solutions and Open Issues, C.-C. Shen a

A Group Based Key Sharing and Management Algorithm for Vehicular Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Zeeshan Shafi Khan

2014-01-01

Full Text Available Vehicular ad hoc networks (VANETs are one special type of ad hoc networks that involves vehicles on roads. Typically like ad hoc networks, broadcast approach is used for data dissemination. Blind broadcast to each and every node results in exchange of useless and irrelevant messages and hence creates an overhead. Unicasting is not preferred in ad-hoc networks due to the dynamic topology and the resource requirements as compared to broadcasting. Simple broadcasting techniques create several problems on privacy, disturbance, and resource utilization. In this paper, we propose media mixing algorithm to decide what information should be provided to each user and how to provide such information. Results obtained through simulation show that fewer number of keys are needed to share compared to simple broadcasting. Privacy is also enhanced through this approach.

INDEPENDENSI HAKIM AD-HOC PADA LINGKUNGAN PERADILAN HUBUNGAN INDUSTRIAL / THE JUDICIAL INDEPENDENCE OF AD-HOC JUDGES IN INDUSTRIAL RELATION COURT

Directory of Open Access Journals (Sweden)

Muhammad Ishar Helmi

2017-08-01

Full Text Available Undang-Undang PPHI mengatur asas penyelesaian perselisihan hubungan industrial dilakukan secara musyawarah mufakat, dengan berprinsip jika terjadi perselisihan antara pekerja/buruh dan pengusaha maka tahap pertama penyelesaian perselisihan tersebut diserahkan pada pihak yang berselisih (bipartit. Ketentuan Pasal 63 ayat (2 dan Pasal 67 ayat (1 huruf f Undang-Undang tersebut mengakibatkan hakim ad-hoc Pengadilan Hubungan Industrial, dalam menjalankan tugas dan tanggung jawabnya memeriksa dan memutus suatu perkara harus mandiri dan lepas dari segala bentuk intervensi lembaga/instansi manapun menjadi terbatasi dan tidak optimal. Hakim ad-hoc Peradilan Hubungan Industrial merupakan hakim yang diusulkan oleh serikat pekerja/serikat buruh, organisasi pengusaha, juga diberhentikan secara hormat oleh serikat pekerja/serikat buruh, organisasi pengusaha tersebut. Hal ini tentunya akan menciderai sistem peradilan yang bebas, tidak memihak dan bersih yang diimpikan karena para hakim akan dikuasai oleh para pihak yang berperkara, karena keberadaan hakim diangkat dan diberhentikan oleh pihak yang akan disidangkan di peradilan hubungan industrial tersebut. PPHI (Industrial Relations Disputes Settlement Act regulates the principle of settlement of industrial relations disputes by consensus, if there is a dispute between employee/workers and employers, the first stage of dispute settlement shall be submitted to disputing party (bipartite settlement. The provisions of Article 63 paragraph (2 and Article 67 paragraph (1 sub-paragraph f of the Act shall result in the ad-hoc judges of the Industrial Relations Court, in carrying out their duties and responsibilities to examine and decide a case shall be independent and kept away from any intervention of any institution. The ad-hoc judges of the Industrial Relations Court is a judge proposed by a trade union, employers organization, also dismissed respectfully by the trade union and the employers organization. This

Statistical analysis applied to safety culture self-assessment

International Nuclear Information System (INIS)

Macedo Soares, P.P.

2002-01-01

Interviews and opinion surveys are instruments used to assess the safety culture in an organization as part of the Safety Culture Enhancement Programme. Specific statistical tools are used to analyse the survey results. This paper presents an example of an opinion survey with the corresponding application of the statistical analysis and the conclusions obtained. Survey validation, Frequency statistics, Kolmogorov-Smirnov non-parametric test, Student (T-test) and ANOVA means comparison tests and LSD post-hoc multiple comparison test, are discussed. (author)

Evolutionary algorithms for mobile ad hoc networks

CERN Document Server

Dorronsoro, Bernabé; Danoy, Grégoire; Pigné, Yoann; Bouvry, Pascal

2014-01-01

Describes how evolutionary algorithms (EAs) can be used to identify, model, and minimize day-to-day problems that arise for researchers in optimization and mobile networking. Mobile ad hoc networks (MANETs), vehicular networks (VANETs), sensor networks (SNs), and hybrid networks—each of these require a designer’s keen sense and knowledge of evolutionary algorithms in order to help with the common issues that plague professionals involved in optimization and mobile networking. This book introduces readers to both mobile ad hoc networks and evolutionary algorithms, presenting basic concepts as well as detailed descriptions of each. It demonstrates how metaheuristics and evolutionary algorithms (EAs) can be used to help provide low-cost operations in the optimization process—allowing designers to put some “intelligence” or sophistication into the design. It also offers efficient and accurate information on dissemination algorithms topology management, and mobility models to address challenges in the ...

Decentralized session initiation protocol solution in ad hoc networks

Science.gov (United States)

Han, Lu; Jin, Zhigang; Shu, Yantai; Dong, Linfang

2006-10-01

With the fast development of ad hoc networks, SIP has attracted more and more attention in multimedia service. This paper proposes a new architecture to provide SIP service for ad hoc users, although there is no centralized SIP server deployed. In this solution, we provide the SIP service by the introduction of two nodes: Designated SIP Server (DS) and its Backup Server (BDS). The nodes of ad hoc network designate DS and BDS when they join the session nodes set and when some pre-defined events occur. A new sip message type called REGISTRAR is presented so nodes can send others REGISTRAR message to declare they want to be DS. According to the IP information taken in the message, an algorithm works like the election of DR and BDR in OSPF protocol is used to vote DS and BDS SIP servers. Naturally, the DS will be replaced by BDS when the DS is down for predicable or unpredictable reasons. To facilitate this, the DS should register to the BDS and transfer a backup of the SIP users' database. Considering the possibility DS or BDS may abruptly go down, a special policy is given. When there is no DS and BDS, a new election procedure is triggered just like the startup phase. The paper also describes how SIP works normally in the decentralized model as well as the evaluation of its performance. All sessions based on SIP in ad hoc such as DS voting have been tested in the real experiments within a 500m*500m square area where about 30 random nodes are placed.

Integration of Body Sensor Networks and Vehicular Ad-hoc Networks for Traffic Safety.

Science.gov (United States)

Reyes-Muñoz, Angelica; Domingo, Mari Carmen; López-Trinidad, Marco Antonio; Delgado, José Luis

2016-01-15

The emergence of Body Sensor Networks (BSNs) constitutes a new and fast growing trend for the development of daily routine applications. However, in the case of heterogeneous BSNs integration with Vehicular ad hoc Networks (VANETs) a large number of difficulties remain, that must be solved, especially when talking about the detection of human state factors that impair the driving of motor vehicles. The main contributions of this investigation are principally three: (1) an exhaustive review of the current mechanisms to detect four basic physiological behavior states (drowsy, drunk, driving under emotional state disorders and distracted driving) that may cause traffic accidents is presented; (2) A middleware architecture is proposed. This architecture can communicate with the car dashboard, emergency services, vehicles belonging to the VANET and road or street facilities. This architecture seeks on the one hand to improve the car driving experience of the driver and on the other hand to extend security mechanisms for the surrounding individuals; and (3) as a proof of concept, an Android real-time attention low level detection application that runs in a next-generation smartphone is developed. The application features mechanisms that allow one to measure the degree of attention of a driver on the base of her/his EEG signals, establish wireless communication links via various standard wireless means, GPRS, Bluetooth and WiFi and issue alarms of critical low driver attention levels.

Ad hoc public disclosure obligations of public companies on the capital market

Directory of Open Access Journals (Sweden)

Marjanski Vladimir

2012-01-01

Full Text Available The author gives a comprehensive analysis of the obligations of public companies regarding the provision of periodical (ad hoc information to the public on the capital market. Ad hoc disclosure is to achieve a number of aims. It is one of the devices to secure the market's functional abilities. By means of regularly fulfilling this obligation, the market is provided with all the relevant information necessary to form adequate prices of market materials - i.e. securities and other financial instruments (the function of market protection. Investors are thus being able to aptly respond to modified circumstances and deliver investment decisions whether to buy or sell market materials the price of which are being changed (the function of investor protection. Due to the fact that the duty of ad hoc disclosure encompasses the obligation to reveal insider information directly affecting the emitter, ad hoc disclosure serves as a preventive measure, i.e. as a protection against illicit trade with insider information (the function of prevention against the abuse of insider information.

Lightning Impacts on Airports - Challenges of Balancing Safety & Efficiency

Science.gov (United States)

Steiner, Matthias; Deierling, Wiebke; Nelson, Eric; Stone, Ken

2013-04-01

Thunderstorms and lightning pose a safety risk to personnel working outdoors, such as people maintaining airport grounds (e.g., mowing grass or repairing runway lighting) or servicing aircraft on ramps (handling baggage, food service, refueling, tugging and guiding aircraft from/to gates, etc.). Since lightning strikes can cause serious injuries or death, it is important to provide timely alerts to airport personnel so that they can get to safety when lightning is imminent. This presentation discusses the challenges and uncertainties involved in using lightning information and stakeholder procedures to ensure safety of outdoor personnel while keeping ramp operations as efficient as possible considering thunderstorm impacts. The findings presented are based on extensive observations of airline operators under thunderstorm impacts. These observations reveal a complex picture with substantial uncertainties related to the (1) source of lightning information (e.g., sensor type, network, data processing) used to base ramp closure decisions on, (2) uncertainties involved in the safety procedures employed by various stakeholders across the aviation industry (yielding notably different rules being applied by multiple airlines even at a single airport), and (3) human factors issues related to the use of decision support tools and the implementation of safety procedures. This research is supported by the United States Federal Aviation Administration (FAA). The views expressed are those of the authors and do not necessarily represent the official policy or position of the FAA.

Node counting in wireless ad-hoc networks

NARCIS (Netherlands)

Evers, J.H.M.; Kiss, D.; Kowalczyk, W.; Navilarekallu, T.; Renger, D.R.M.; Sella, L.; Timperio, V.; Viorel, A.; Wijk, van A.C.C.; Yzelman, A.J.; Planqué, B.; Bhulai, S.; Hulshof, J.; Kager, W.; Rot, T.

2012-01-01

We study wireless ad-hoc networks consisting of small microprocessors with limited memory, where the wireless communication between the processors can be highly unreliable. For this setting, we propose a number of algorithms to estimate the number of nodes in the network, and the number of direct

Fungal Zinc Homeostasis - A Tug of War Between the Pathogen and Host.

Science.gov (United States)

Walencik, Paulina K; Watly, Joanna; Rowinska-Zyrek, Magdalena

2016-01-01

In the last decade, drug resistant invasive mycoses have become significantly more common and new antifungal drugs and ways to specifically deliver them to the fungal cell are being looked for. One of the biggest obstacles in finding such comes from the fact that fungi share essential metabolic pathways with humans. One significant difference in the metabolism of those two cells that can be challenged when looking for possible selective therapeutics is the uptake of zinc, a nutrient crucial for the fungal survival and virulence. This work summarizes the recent advances in the biological inorganic chemistry of zinc metabolism in fungi. The regulation of zinc uptake, various types of its transmembrane transport, storage and the maintenance of intracellular zinc homeostasis is discussed in detail, with a special focus on the concept of a constant 'tug of war' over zinc between the fungus and its host, with the host trying to withhold essential Zn(II), and the fungus counteracting by producing high-affinity zinc binding molecules.

Information Sharing Modalities for Mobile Ad-Hoc Networks

Science.gov (United States)

de Spindler, Alexandre; Grossniklaus, Michael; Lins, Christoph; Norrie, Moira C.

Current mobile phone technologies have fostered the emergence of a new generation of mobile applications. Such applications allow users to interact and share information opportunistically when their mobile devices are in physical proximity or close to fixed installations. It has been shown how mobile applications such as collaborative filtering and location-based services can take advantage of ad-hoc connectivity to use physical proximity as a filter mechanism inherent to the application logic. We discuss the different modes of information sharing that arise in such settings based on the models of persistence and synchronisation. We present a platform that supports the development of applications that can exploit these modes of ad-hoc information sharing and, by means of an example, show how such an application can be realised based on the supported event model.

An implementation of traffic light system using multi-hop Ad hoc networks

KAUST Repository

Ansari, Imran Shafique

2009-08-01

In ad hoc networks nodes cooperate with each other to form a temporary network without the aid of any centralized administration. No wired base station or infrastructure is supported, and each host communicates via radio packets. Each host must act as a router, since routes are mostly multi-hop, due to the limited power transmission set by government agencies, (e.g. the Federal Communication Commission (FCC), which is 1 Watt in Industrial Scientific and Medical (ISM) band. The natures of wireless mobile ad hoc networks depend on batteries or other fatiguing means for their energy. A limited energy capacity may be the most significant performance constraint. Therefore, radio resource and power management is an important issue of any wireless network. In this paper, a design for traffic light system employing ad hoc networks is proposed. The traffic light system runs automatically based on signals sent through a multi-hop ad hoc network of \\'n\\' number of nodes utilizing the Token Ring protocol, which is efficient for this application from the energy prospective. The experiment consists of a graphical user interface that simulates the traffic lights and laptops (which have wireless network adapters) are used to run the graphical user interface and are responsible for setting up the ad hoc network between them. The traffic light system has been implemented utilizing A Mesh Driver (which allows for more than one wireless device to be connected simultaneously) and Java-based client-server programs. © 2009 IEEE.

SVANET: A Smart Vehicular Ad Hoc Network for Efficient Data Transmission with Wireless Sensors

Directory of Open Access Journals (Sweden)

Prasan Kumar Sahoo

2014-11-01

Full Text Available Wireless sensors can sense any event, such as accidents, as well as icy roads, and can forward the rescue/warning messages through intermediate vehicles for any necessary help. In this paper, we propose a smart vehicular ad hoc network (SVANET architecture that uses wireless sensors to detect events and vehicles to transmit the safety and non-safety messages efficiently by using different service channels and one control channel with different priorities. We have developed a data transmission protocol for the vehicles in the highway, in which data can be forwarded with the help of vehicles if they are connected with each other or data can be forwarded with the help of nearby wireless sensors. Our data transmission protocol is designed to increase the driving safety, to prevent accidents and to utilize channels efficiently by adjusting the control and service channel time intervals dynamically. Besides, our protocol can transmit information to vehicles in advance, so that drivers can decide an alternate route in case of traffic congestion. For various data sharing, we design a method that can select a few leader nodes among vehicles running along a highway to broadcast data efficiently. Simulation results show that our protocol can outperform the existing standard in terms of the end to end packet delivery ratio and latency.

Enhanced WWTP effluent organic matter removal in hybrid ozonation-coagulation (HOC) process catalyzed by Al-based coagulant

Energy Technology Data Exchange (ETDEWEB)

Jin, Xin [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China); Jin, Pengkang, E-mail: pkjin@hotmail.com [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China); Hou, Rui [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China); Yang, Lei [Department of Materials Science and Engineering, Monash University, Clayton, VIC, 3800 (Australia); Wang, Xiaochang C., E-mail: xcwang@xauat.edu.cn [School of Environmental and Municipal Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi Province, 710055 (China)

2017-04-05

Highlights: • A novel HOC process was firstly put forward to apply in wastewater reclamation. • Interactions between ozone and Al-based coagulants was found in the HOC process. • Ozonation can be catalyzed and enhanced by Al-based coagulants in the HOC process. • HOC process showed better organics removal than pre-ozonation-coagulation process. - Abstract: A novel hybrid ozonation-coagulation (HOC) process was developed for application in wastewater reclamation. In this process, ozonation and coagulation occurred simultaneously within a single unit. Compared with the conventional pre-ozonation-coagulation process, the HOC process exhibited much better performance in removing dissolved organic matters. In particular, the maximal organic matters removal efficiency was obtained at the ozone dosage of 1 mgO{sub 3}/mg DOC at each pH value (pH 5, 7 and 9). In order to interpret the mechanism of the HOC process, ozone decomposition was monitored. The results indicated that ozone decomposed much faster in the HOC process. Moreover, by using the reagent of O{sub 3}-resistant hydroxyl radical (·OH) probe compound, para-chlorobenzoic acid (pCBA), and electron paramagnetic resonance (EPR) analysis, it was observed that the HOC process generated higher content of ·OH compared with pre-ozonation process. This indicates that the ·OH oxidation reaction as the key step can be catalyzed and enhanced by Al-based coagulants and their hydrolyzed products in this developed process. Thus, based on the catalytic effects of Al-based coagulants on ozonation, the HOC process provides a promising alternative to the conventional technology for wastewater reclamation in terms of higher efficiency.

Ad Hoc on-Demand Distance Vector (AODV Routing Protocol Performance Evaluation on Hybrid Ad Hoc Network: Comparison of Result of Ns-2 Simulation and Implementation on Testbed using PDA

Directory of Open Access Journals (Sweden)

Riri Sari

2010-10-01

Full Text Available In Mobile Ad hoc NETwork (MANET, node supplemented with wireless equipment has the capacity to manage and organise autonomously, without the presence of network infrastructures. Hybrid ad hoc network, enable several nodes to move freely (mobile to create instant communication. Independent from infrastructure. They could access the Local Area Network (LAN or the Internet. Functionalities of ad hoc network very much dependent on the routing protocol that determines the routing around node. Ad hoc On-demand Distance Vector (AODV is one of routing protocols in ad hoc network which has a reactive characteristic. This protocol is the most common protocol being researched and used. In this Research, AODV protocol investigation was conducted by developing a testbed using Personal Computer, several Laptops (the Linux Red Hat operation system 9.0 and Fedora Core 2, and Personal Digital Assistant (PDA. This research also made a complete package by mean of cross compilation for PDA iPAQ. In general, results obtained from the simulation of AODV protocol using Network Simulator NS-2 are packet delivery ratio 99.89%, end-to-end delay of 0.14 seconds and routing overhead of 1,756.61 byte per second. Afterwards results from simulation were compared to results from testbed. Results obtained from testbed are as follows: the packet delivery ratio is 99.57%, the end-to-end delay is 1.004 seconds and the routing overhead is 1,360.36 byte per second.

Contribution to design a communication framework for vehicular ad hoc networks in urban scenarios

OpenAIRE

Tripp Barba, Carolina

2013-01-01

The constant mobility of people, the growing need to be always connected, the large number of vehicles that nowadays can be found in the roads and the advances in technology make Vehicular Ad hoc Networks (VANETs) be a major area of research. Vehicular Ad hoc Networks are a special type of wireless Mobile Ad hoc Networks (MANETs), which allow a group of mobile nodes configure a temporary network and maintain it without the need of a fixed infrastructure. A vehicular network presents some spec...

Proposal of interference reduction routing for ad-hoc networks

Directory of Open Access Journals (Sweden)

Katsuhiro Naito

2010-10-01

Full Text Available In this paper, we propose an interference reduction routing protocol for ad-hoc networks. The interference is one of the degradation factors in wireless communications. In the ad-hoc network, some nodes communicate simultaneously. Therefore, these communications cause interference each other, and some packets are corrupted due to interference from another node. In the proposed protocol, each node estimates required transmission power according to hello messages. Therefore, the node can transmit a data packet with minimum required transmission power. Consequently, the interference against neighbor nodes can be reduced. From simulation results, we can find that the proposed protocol can reduce the number of control messages and can improve the throughput performance.

Integration of Body Sensor Networks and Vehicular Ad-hoc Networks for Traffic Safety

Directory of Open Access Journals (Sweden)

Angelica Reyes-Muñoz

2016-01-01

Full Text Available The emergence of Body Sensor Networks (BSNs constitutes a new and fast growing trend for the development of daily routine applications. However, in the case of heterogeneous BSNs integration with Vehicular ad hoc Networks (VANETs a large number of difficulties remain, that must be solved, especially when talking about the detection of human state factors that impair the driving of motor vehicles. The main contributions of this investigation are principally three: (1 an exhaustive review of the current mechanisms to detect four basic physiological behavior states (drowsy, drunk, driving under emotional state disorders and distracted driving that may cause traffic accidents is presented; (2 A middleware architecture is proposed. This architecture can communicate with the car dashboard, emergency services, vehicles belonging to the VANET and road or street facilities. This architecture seeks on the one hand to improve the car driving experience of the driver and on the other hand to extend security mechanisms for the surrounding individuals; and (3 as a proof of concept, an Android real-time attention low level detection application that runs in a next-generation smartphone is developed. The application features mechanisms that allow one to measure the degree of attention of a driver on the base of her/his EEG signals, establish wireless communication links via various standard wireless means, GPRS, Bluetooth and WiFi and issue alarms of critical low driver attention levels.

Integration of Body Sensor Networks and Vehicular Ad-hoc Networks for Traffic Safety

Science.gov (United States)

Reyes-Muñoz, Angelica; Domingo, Mari Carmen; López-Trinidad, Marco Antonio; Delgado, José Luis

2016-01-01

The emergence of Body Sensor Networks (BSNs) constitutes a new and fast growing trend for the development of daily routine applications. However, in the case of heterogeneous BSNs integration with Vehicular ad hoc Networks (VANETs) a large number of difficulties remain, that must be solved, especially when talking about the detection of human state factors that impair the driving of motor vehicles. The main contributions of this investigation are principally three: (1) an exhaustive review of the current mechanisms to detect four basic physiological behavior states (drowsy, drunk, driving under emotional state disorders and distracted driving) that may cause traffic accidents is presented; (2) A middleware architecture is proposed. This architecture can communicate with the car dashboard, emergency services, vehicles belonging to the VANET and road or street facilities. This architecture seeks on the one hand to improve the car driving experience of the driver and on the other hand to extend security mechanisms for the surrounding individuals; and (3) as a proof of concept, an Android real-time attention low level detection application that runs in a next-generation smartphone is developed. The application features mechanisms that allow one to measure the degree of attention of a driver on the base of her/his EEG signals, establish wireless communication links via various standard wireless means, GPRS, Bluetooth and WiFi and issue alarms of critical low driver attention levels. PMID:26784204

Voice Communications over 802.11 Ad Hoc Networks: Modeling, Optimization and Call Admission Control

Science.gov (United States)

Xu, Changchun; Xu, Yanyi; Liu, Gan; Liu, Kezhong

Supporting quality-of-service (QoS) of multimedia communications over IEEE 802.11 based ad hoc networks is a challenging task. This paper develops a simple 3-D Markov chain model for queuing analysis of IEEE 802.11 MAC layer. The model is applied for performance analysis of voice communications over IEEE 802.11 single-hop ad hoc networks. By using the model, we finish the performance optimization of IEEE MAC layer and obtain the maximum number of voice calls in IEEE 802.11 ad hoc networks as well as the statistical performance bounds. Furthermore, we design a fully distributed call admission control (CAC) algorithm which can provide strict statistical QoS guarantee for voice communications over IEEE 802.11 ad hoc networks. Extensive simulations indicate the accuracy of the analytical model and the CAC scheme.

Ad Hoc Wireless Networking and Shared Computation for Autonomous Multirobot Systems

OpenAIRE

Bevilacqua, Riccardo; Hall, Jason S.; Horning, James; Romano, Marcello

2009-01-01

The article of record as published may be located at http://dx.doi.org/10.2514/1.40734 A wireless ad hoc network is introduced that enables inter-robot communication and shared computation among multiple robots with PC/104-based single board computers running the real-time application interface patched Linux operating system. Through the use of IEEE 802.11 ad hoc technology and User Datagram Protocol, each robot is able to exchange data without the need of a centralized router ...

Long noncoding RNA TUG1 is a diagnostic factor in lung adenocarcinoma and suppresses apoptosis via epigenetic silencing of BAX

OpenAIRE

Liu, Huan; Zhou, Guizhi; Fu, Xin; Cui, Haiyan; Pu, Guangrui; Xiao, Yao; Sun, Wei; Dong, Xinhua; Zhang, Libin; Cao, Sijia; Li, Guiqin; Wu, Xiaowei; Yang, Xu

2017-01-01

Lung cancer is one of the leading causes of cancer-related mortality, and responds badly to existing treatment. Thus, it is of urgent need to identify novel diagnostic markers and therapeutic targets. Increasing evidences have indicated that long non-coding RNAs (lncRNAs) play an important role in initiation and progression of lung cancer. However, the role of lncRNA Taurine upregulated 1 (TUG1) in lung adenocarcinoma (LAD) progression is not well known. In this study, we determined the diagn...

Guidelines for the review research reactor safety. Reference document for IAEA Integrated Safety Assessment of Research Reactors (INSARR)

International Nuclear Information System (INIS)

1997-01-01

In 1992, the IAEA published new safety standards for research reactors as part of the set of publications considered by its Research Reactor Safety Programme (RRSP). This set also includes publications giving guidance for all safety aspects related to the lifetime of a research reactor. In addition, the IAEA has also revised the Safety Standards for radiation protection. Consequently, it was considered advisable to revise the Integrated Safety Assessment of Research Reactors (INSARR) procedures to incorporate the new requirements and guidance as well as to extend the scope of the safety reviews to currently operating research reactors. The present report is the result of this revision. The purpose of this report is to give guidance on the preparation, execution, reporting and follow-up of safety review mission to research reactors as conducted by the IAEA under its INSARR missions safety service. However, it will also be of assistance to operators and regulators in conducting: (a) ad hoc safety assessments of research reactors to address individual issues such as ageing or safety culture; and (b) other types of safety reviews such as internal and peer reviews and regulatory inspections

Safety and efficacy of tiotropium in patients switching from HandiHaler to Respimat in the TIOSPIR trial

DEFF Research Database (Denmark)

Dahl, Ronald; Calverley, Peter M A; Anzueto, Antonio

2015-01-01

OBJECTIVES: This post hoc analysis of TIOtropium Safety and Performance In Respimat (TIOSPIR) evaluated safety and exacerbation efficacy in patients with stable (≥2 months) use of tiotropium HandiHaler 18 µg (HH18) prior to study entry, to evaluate whether there was a difference in risk for patie...

Analysis of DDoS Attack Effect and Protection Scheme in Wireless Mobile Ad-hoc Network

OpenAIRE

Ramratan Ahirwal; Leeladhar Mahour

2012-01-01

In Wireless mobile Ad Hoc Networks (MANET) every node functions as transmitter, router and data sink is network without infrastructure. Detecting malicious nodes in an open ad-hoc network in whichparticipating nodes have no previous security associations presents a number of challenges not faced by traditional wired networks. Traffic monitoring in wired networks is usually performed at switches,routers and gateways, but an ad-hoc network does not have these types of network elements where the...

Cognitive radio application for vehicular ad hoc networks (VANETS

Directory of Open Access Journals (Sweden)

Miladić Suzana D.

2016-01-01

Full Text Available This paper presents the application of cognitive radio technology in vehicular ad-hoc networks aimed to improve the communications between vehicles themselves as well as between vehicles and roadside infrastructure. Due to dynamic approach of spectrum access, cognitive radio is a technology that enables more efficient usage of radio-frequency spectrum. We review actual approaches and discuss research challenges related to the use of cognitive radio technology in vehicular ad hoc networks with emphasis on architecture, spectrum management as well as QoS optimization. The researching on cognitive radio application in vehicular networks is still developing and there are not many experimental platforms due to their complex setups. Some related research projects and cognitive radio realizations are provided in this paper.

Design study of RL10 derivatives. Volume 3, part 2: Operational and flight support plan. [analysis of transportation requirements for rocket engine in support of space tug program

Science.gov (United States)

Shubert, W. C.

1973-01-01

Transportation requirements are considered during the engine design layout reviews and maintenance engineering analyses. Where designs cannot be influenced to avoid transportation problems, the transportation representative is advised of the problems permitting remedies early in the program. The transportation representative will monitor and be involved in the shipment of development engine and GSE hardware between FRDC and vehicle manufacturing plant and thereby will be provided an early evaluation of the transportation plans, methods and procedures to be used in the space tug support program. Unanticipated problems discovered in the shipment of development hardware will be known early enough to permit changes in packaging designs and transportation plans before the start of production hardware and engine shipments. All conventional transport media can be used for the movement of space tug engines. However, truck transport is recommended for ready availability, variety of routes, short transit time, and low cost.

Ad Hoc Physical Hilbert Spaces in Quantum Mechanics

Czech Academy of Sciences Publication Activity Database

Fernandez, F. M.; Garcia, J.; Semorádová, Iveta; Znojil, Miloslav

2015-01-01

Roč. 54, č. 12 (2015), s. 4187-4203 ISSN 0020-7748 Institutional support: RVO:61389005 Keywords : quantum mechanics * physical Hilbert spaces * ad hoc inner product * singular potentials regularized * low lying energies Subject RIV: BE - Theoretical Physics Impact factor: 1.041, year: 2015

Wireless Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Hong-Chuan Yang

2007-01-01

Full Text Available We study the energy-efficient configuration of multihop paths with automatic repeat request (ARQ mechanism in wireless ad hoc networks. We adopt a cross-layer design approach and take both the quality of each radio hop and the battery capacity of each transmitting node into consideration. Under certain constraints on the maximum tolerable transmission delay and the required packet delivery ratio, we solve optimization problems to jointly schedule the transmitting power of each transmitting node and the retransmission limit over each hop. Numerical results demonstrate that the path configuration methods can either significantly reduce the average energy consumption per packet delivery or considerably extend the average lifetime of the multihop route.

Contribution to design a communication framework for vehicular ad hoc networks in urban scenarios

OpenAIRE

Tripp Barba, Carolina

2013-01-01

La movilidad constante de las personas y la creciente necesidad de estar conectados en todo momento ha hecho de las redes vehiculares un área cuyo interés ha ido en aumento. La gran cantidad de vehículos que hay en la actualidad, y los avances tecnológicos han hecho de las redes vehiculares (VANETS, Vehicular Ad hoc Networks) un gran campo de investigación. Las redes vehiculares son un tipo especial de redes móviles ad hoc inalámbricas, las cuales, al igual que las redes MANET (Mobile Ad hoc ...

MAC Protocol for Ad Hoc Networks Using a Genetic Algorithm

Science.gov (United States)

Elizarraras, Omar; Panduro, Marco; Méndez, Aldo L.

2014-01-01

The problem of obtaining the transmission rate in an ad hoc network consists in adjusting the power of each node to ensure the signal to interference ratio (SIR) and the energy required to transmit from one node to another is obtained at the same time. Therefore, an optimal transmission rate for each node in a medium access control (MAC) protocol based on CSMA-CDMA (carrier sense multiple access-code division multiple access) for ad hoc networks can be obtained using evolutionary optimization. This work proposes a genetic algorithm for the transmission rate election considering a perfect power control, and our proposition achieves improvement of 10% compared with the scheme that handles the handshaking phase to adjust the transmission rate. Furthermore, this paper proposes a genetic algorithm that solves the problem of power combining, interference, data rate, and energy ensuring the signal to interference ratio in an ad hoc network. The result of the proposed genetic algorithm has a better performance (15%) compared to the CSMA-CDMA protocol without optimizing. Therefore, we show by simulation the effectiveness of the proposed protocol in terms of the throughput. PMID:25140339

MAC Protocol for Ad Hoc Networks Using a Genetic Algorithm

Directory of Open Access Journals (Sweden)

Omar Elizarraras

2014-01-01

Full Text Available The problem of obtaining the transmission rate in an ad hoc network consists in adjusting the power of each node to ensure the signal to interference ratio (SIR and the energy required to transmit from one node to another is obtained at the same time. Therefore, an optimal transmission rate for each node in a medium access control (MAC protocol based on CSMA-CDMA (carrier sense multiple access-code division multiple access for ad hoc networks can be obtained using evolutionary optimization. This work proposes a genetic algorithm for the transmission rate election considering a perfect power control, and our proposition achieves improvement of 10% compared with the scheme that handles the handshaking phase to adjust the transmission rate. Furthermore, this paper proposes a genetic algorithm that solves the problem of power combining, interference, data rate, and energy ensuring the signal to interference ratio in an ad hoc network. The result of the proposed genetic algorithm has a better performance (15% compared to the CSMA-CDMA protocol without optimizing. Therefore, we show by simulation the effectiveness of the proposed protocol in terms of the throughput.

Source Authentication for Multicast in Mobile Ad Hoc Networks

National Research Council Canada - National Science Library

Ramachandran, Prabha

2003-01-01

Recent emergence and popularity of mobile ad hoc networks in a host of current-day applications has instigated a suite of research challenges, primarily in routing and security issues for such networks...

A peer-to-peer file search and download protocol for wireless ad-hoc networks

NARCIS (Netherlands)

Sözer, Hasan; Tekkalmaz, M.; Korpeoglu, I.

Deployment of traditional peer-to-peer file sharing systems on a wireless ad-hoc network introduces several challenges. Information and workload distribution as well as routing are major problems for members of a wireless ad-hoc network, which are only aware of their immediate neighborhood. In this

Analysis and Enhancements of Leader Elections algorithms in Mobile Ad Hoc Networks

OpenAIRE

Shayeji, Mohammad H. Al; Al-Azmi, AbdulRahman R.; Al-Azmi, AbdulAziz R.; Samrajesh, M. D.

2012-01-01

Mobile Ad Hoc networks (MANET), distinct from traditional distributed systems, are dynamic and self-organizing networks. MANET requires a leader to coordinate and organize tasks. The challenge is to have the right election algorithm that chooses the right leader based on various factors in MANET. In this paper, we analyze four leader election algorithms used in mobile Ad Hoc Networks. Factors considered in our analysis are time complexity, message complexity, assumptions considered, fault tol...

User-centred and context-aware identity management in mobile ad-hoc networks

CERN Document Server

Arabo, Abdullahi

2013-01-01

The emergent notion of ubiquitous computing makes it possible for mobile devices to communicate and provide services via networks connected in an ad-hoc manner. These have resulted in the proliferation of wireless technologies such as Mobile Ad-hoc Networks (MANets), which offer attractive solutions for services that need flexible setup as well as dynamic and low cost wireless connectivity. However, the growing trend outlined above also raises serious concerns over Identity Management (IM) du...

Centralized cooperative spectrum sensing for ad-hoc disaster relief network clusters

DEFF Research Database (Denmark)

Pratas, Nuno; Marchetti, Nicola; Prasad, Neeli R.

2010-01-01

Disaster relief networks have to be highly adaptable and resilient. Cognitive radio enhanced ad-hoc architecture have been put forward as a candidate to enable such networks. Spectrum sensing is the cornerstone of the cognitive radio paradigm, and it has been the target of intensive research....... The main common conclusion was that the achievable spectrum sensing accuracy can be greatly enhanced through the use of cooperative sensing schemes. When considering applying Cognitive Radio to ad-hoc disaster relief networks, spectrum sensing cooperative schemes are paramount. A centralized cluster...

LAMAN: Load Adaptable MAC for Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Realp Marc

2005-01-01

Full Text Available In mobile ad hoc radio networks, mechanisms on how to access the radio channel are extremely important in order to improve network efficiency. In this paper, the load adaptable medium access control for ad hoc networks (LAMAN protocol is described. LAMAN is a novel decentralized multipacket MAC protocol designed following a cross-layer approach. Basically, this protocol is a hybrid CDMA-TDMA-based protocol that aims at throughput maximization in multipacket communication environments by efficiently combining contention and conflict-free protocol components. Such combination of components is used to adapt the nodes' access priority to changes on the traffic load while, at the same time, accounting for the multipacket reception (MPR capability of the receivers. A theoretical analysis of the system is developed presenting closed expressions of network throughput and packet delay. By simulations the validity of our analysis is shown and the performances of a LAMAN-based system and an Aloha-CDMA-based one are compared.

Typicality Mediates Performance during Category Verification in Both Ad-Hoc and Well-Defined Categories

Science.gov (United States)

Sandberg, Chaleece; Sebastian, Rajani; Kiran, Swathi

2012-01-01

Background: The typicality effect is present in neurologically intact populations for natural, ad-hoc, and well-defined categories. Although sparse, there is evidence of typicality effects in persons with chronic stroke aphasia for natural and ad-hoc categories. However, it is unknown exactly what influences the typicality effect in this…

On the impact of network dynamics on a discovery protocol for ad-hoc networks

NARCIS (Netherlands)

Liu, F.; Heijenk, Geert

A very promising approach to discovering services and context information in ad-hoc networks is based on the use of Attenuated Bloom filters. In this paper we analyze the impact of changes in the connectivity of an ad-hoc network on this approach. We evaluate the performance of the discovery

What Is the Problem of Ad Hoc Hypotheses?

Science.gov (United States)

Bamford, Greg

1999-01-01

Philosophers' attempts to convincingly explicate the received view of an ad hoc hypothesis--that it accounts for only the observations it was designed to account for--have been unsuccessful. Familiar and firmer criteria for evaluating the hypotheses or modified theories so classified are characteristically available. Contains 41 references.…

Deny-by-Default Distributed Security Policy Enforcement in Mobile Ad Hoc Networks

Science.gov (United States)

Alicherry, Mansoor; Keromytis, Angelos D.; Stavrou, Angelos

Mobile Ad-hoc Networks (MANETs) are increasingly employed in tactical military and civil rapid-deployment networks, including emergency rescue operations and ad hoc disaster-relief networks. However, this flexibility of MANETs comes at a price, when compared to wired and base station-based wireless networks: MANETs are susceptible to both insider and outsider attacks. This is mainly because of the lack of a well-defined defense perimeter preventing the effective use of wired defenses including firewalls and intrusion detection systems.

Multiplayer Game for DDoS Attacks Resilience in Ad Hoc Networks

DEFF Research Database (Denmark)

Mikalas, Antonis; Komninos, Nikos; Prasad, Neeli R.

2011-01-01

This paper proposes a multiplayer game to prevent Distributed Denial of Service attack (DDoS) in ad hoc networks. The multiplayer game is based on game theory and cryptographic puzzles. We divide requests from nodes into separate groups which decreases the ability of malicious nodes to cooperate...... with one another in order to effectively make a DDoS attack. Finally, through our experiments we have shown that the total overhead of the multiplayer game as well as the the total time that each node needs to be served is affordable for devices that have limited resources and for environments like ad hoc...

Safety management of radioisotopes and others in educational institutions

International Nuclear Information System (INIS)

1981-01-01

Radioisotopes are extensively used in the fields of research in various educational institutions. While considerable progress has been seen in the safety management of RI utilization, such accidents as the loss of radioisotopes and radioactive contamination occurred. Under the situation, the safety management of RIs and others in RI-using facilities provided by the law has been examined by the ad hoc committee. A report by the committee is described as follows: need for a RI safety management organization, defining the responsibility of the chief technicians handling radiation, need for the practices of using RIs, etc. in education and traininng, planned RI-handling facilities, cautions for the loss of RIs and the contamination, centralization in RI safety management, improvement of remuneration for the chief technicians handling radiation, occasional restudy on the safety management of RIs, etc. (J.P.N.)

Interference in wireless ad hoc networks with smart antennas

KAUST Repository

Alabdulmohsin, Ibrahim

2014-01-01

In this paper, we show that the use of directional antennas in wireless ad hoc networks can actually increase interference due to limitations of virtual carrier sensing. We derive a simple mathematical expression for interference in both physical

Ad Hoc Human Information Nets for Asymmetric Threat Surveillance

National Research Council Canada - National Science Library

Thiruvathukal, George

2003-01-01

...: Hybrid-Hierarchical Micro-Databases, Query Optimization, and XML for Embedded Systems. After meeting with the program manager, Tom Armour, in Washington, DC, we were able to get a better perspective on the ad hoc nature of the solicitation...

Modelling Mobility in Mobile AD-HOC Network Environments ...

African Journals Online (AJOL)

In the simulation of mobile ad-hoc networks (MANETs), the probability distribution governing the movement of nodes typically varies over time and converges to a steady state distribution, known as the stationary distribution. This paper presents and evaluates the stationary distribution for location, speed and pause time of a ...

Dynamic Mobile IP routers in ad hoc networks

NARCIS (Netherlands)

Kock, B.A.; Schmidt, J.R.

2005-01-01

This paper describes a concept combining mobile IP and ad hoc routing to create a robust mobile network. In this network all nodes are mobile and globally and locally reachable under the same IP address. Essential for implementing this network are the dynamic mobile IP routers. They act as gateways

Ad Hoc Categories and False Memories: Memory Illusions for Categories Created On-The-Spot

Science.gov (United States)

Soro, Jerônimo C.; Ferreira, Mário B.; Semin, Gün R.; Mata, André; Carneiro, Paula

2017-01-01

Three experiments were designed to test whether experimentally created ad hoc associative networks evoke false memories. We used the DRM (Deese, Roediger, McDermott) paradigm with lists of ad hoc categories composed of exemplars aggregated toward specific goals (e.g., going for a picnic) that do not share any consistent set of features. Experiment…

Energy management in wireless cellular and ad-hoc networks

CERN Document Server

Imran, Muhammad; Qaraqe, Khalid; Alouini, Mohamed-Slim; Vasilakos, Athanasios

2016-01-01

This book investigates energy management approaches for energy efficient or energy-centric system design and architecture and presents end-to-end energy management in the recent heterogeneous-type wireless network medium. It also considers energy management in wireless sensor and mesh networks by exploiting energy efficient transmission techniques and protocols. and explores energy management in emerging applications, services and engineering to be facilitated with 5G networks such as WBANs, VANETS and Cognitive networks. A special focus of the book is on the examination of the energy management practices in emerging wireless cellular and ad hoc networks. Considering the broad scope of energy management in wireless cellular and ad hoc networks, this book is organized into six sections covering range of Energy efficient systems and architectures; Energy efficient transmission and techniques; Energy efficient applications and services. .

Power-Controlled MAC Protocols with Dynamic Neighbor Prediction for Ad hoc Networks

Institute of Scientific and Technical Information of China (English)

LI Meng; ZHANG Lin; XIAO Yong-kang; SHAN Xiu-ming

2004-01-01

Energy and bandwidth are the scarce resources in ad hoc networks because most of the mobile nodes are battery-supplied and share the exclusive wireless medium. Integrating the power control into MAC protocol is a promising technique to fully exploit these precious resources of ad hoc wireless networks. In this paper, a new intelligent power-controlled Medium Access Control (MAC) (iMAC) protocol with dynamic neighbor prediction is proposed. Through the elaborate design of the distributed transmit-receive strategy of mobile nodes, iMAC greatly outperforms the prevailing IEEE 802.11 MAC protocols in not only energy conservation but also network throughput. Using the Dynamic Neighbor Prediction (DNP), iMAC performs well in mobile scenes. To the best of our knowledge, iMAC is the first protocol that considers the performance deterioration of power-controlled MAC protocols in mobile scenes and then proposes a solution. Simulation results indicate that DNP is important and necessary for power-controlled MAC protocols in mobile ad hoc networks.

A User Authentication Scheme Based on Elliptic Curves Cryptography for Wireless Ad Hoc Networks.

Science.gov (United States)

Chen, Huifang; Ge, Linlin; Xie, Lei

2015-07-14

The feature of non-infrastructure support in a wireless ad hoc network (WANET) makes it suffer from various attacks. Moreover, user authentication is the first safety barrier in a network. A mutual trust is achieved by a protocol which enables communicating parties to authenticate each other at the same time and to exchange session keys. For the resource-constrained WANET, an efficient and lightweight user authentication scheme is necessary. In this paper, we propose a user authentication scheme based on the self-certified public key system and elliptic curves cryptography for a WANET. Using the proposed scheme, an efficient two-way user authentication and secure session key agreement can be achieved. Security analysis shows that our proposed scheme is resilient to common known attacks. In addition, the performance analysis shows that our proposed scheme performs similar or better compared with some existing user authentication schemes.

Mitigate DoS and DDoS attacks in Mobile Ad Hoc Networks

DEFF Research Database (Denmark)

Michalas, Antonis; Komninos, Nikos; Prasad, Neeli R.

2011-01-01

This paper proposes a technique to defeat Denial of Service (DoS) and Distributed Denial of Service (DDoS) attacks in Ad Hoc Networks. The technique is divided into two main parts and with game theory and cryptographic puzzles. Introduced first is a new client puzzle to prevent DoS attacks...... in DoS and DDoS attacks. Experimental results show the effectiveness of the approach for devices with limited resources and for environments like ad hoc networks where nodes must exchange information quickly....

Secure Geographic Routing in Ad Hoc and Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Zahariadis Theodore

2010-01-01

Full Text Available Security in sensor networks is one of the most relevant research topics in resource constrained wireless devices and networks. Several attacks can be suffered in ad hoc and wireless sensor networks (WSN, which are highly susceptible to attacks, due to the limited resources of the nodes. In this paper, we propose innovative and lightweight localization techniques that allow for intrusion identification and isolation schemes and provide accurate location information. This information is used by our routing protocol which additionally incorporates a distributed trust model to prevent several routing attacks to the network. We finally evaluate our algorithms for accurate localization and for secure routing which have been implemented and tested in real ad hoc and wireless sensor networks.

Distributed generation of shared RSA keys in mobile ad hoc networks

Science.gov (United States)

Liu, Yi-Liang; Huang, Qin; Shen, Ying

2005-12-01

Mobile Ad Hoc Networks is a totally new concept in which mobile nodes are able to communicate together over wireless links in an independent manner, independent of fixed physical infrastructure and centralized administrative infrastructure. However, the nature of Ad Hoc Networks makes them very vulnerable to security threats. Generation and distribution of shared keys for CA (Certification Authority) is challenging for security solution based on distributed PKI(Public-Key Infrastructure)/CA. The solutions that have been proposed in the literature and some related issues are discussed in this paper. The solution of a distributed generation of shared threshold RSA keys for CA is proposed in the present paper. During the process of creating an RSA private key share, every CA node only has its own private security. Distributed arithmetic is used to create the CA's private share locally, and that the requirement of centralized management institution is eliminated. Based on fully considering the Mobile Ad Hoc network's characteristic of self-organization, it avoids the security hidden trouble that comes by holding an all private security share of CA, with which the security and robustness of system is enhanced.

Verification of mobile ad hoc networks : an algebraic approach

NARCIS (Netherlands)

Ghassemi, F.; Fokkink, W.J.; Movaghar, A.

2011-01-01

We introduced Computed Network Process Theory to reason about protocols for mobile ad hoc networks (MANETs). Here we explore the applicability of our framework in two regards: model checking and equational reasoning. The operational semantics of our framework is based on constrained labeled

Challenges of evidence acquisition in wireless ad-hoc networks

CSIR Research Space (South Africa)

Mutanga, MB

2010-05-01

Full Text Available a big challenge. Thus, the aim of this paper is to explore the challenges of acquiring live evidence in wireless ad-hoc networks. We also give some legal requirements of evidence admissibility as outlined in the Communications and Transactions Act...

On the status of the EFR Euro-Breeder and its passive safety features

International Nuclear Information System (INIS)

Marth, W.

1992-01-01

The Project of the EFR, the European Fast Reactor, is characterized by close European cooperation among power utilities, plant vendors, and research centers. In the present phase up until 1993 a consistent design of the nuclear part of the plant is being elaborated with the inclusion of a site-independent safety report. The most important design features, especially those in the field of passive safety, must be backed up by reliable R and D findings. These findings will enable the ad hoc Safety Club, a body of European safety experts, to pass its vote on the general licensability of the plant concept. (orig.) [de

Search for Production of Single Top Quarks Via tcg and tug Flavor-Changing-Neutral-Current Couplings

Science.gov (United States)

Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T.; Aguilo, E.; Ahn, S. H.; Ahsan, M.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G. A.; Anastasoaie, M.; Ancu, L. S.; Andeen, T.; Anderson, S.; Andrieu, B.; Anzelc, M. S.; Arnoud, Y.; Arov, M.; Askew, A.; Åsman, B.; Assis Jesus, A. C. S.; Atramentov, O.; Autermann, C.; Avila, C.; Ay, C.; Badaud, F.; Baden, A.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, P.; Banerjee, S.; Barberis, E.; Barfuss, A.-F.; Bargassa, P.; Baringer, P.; Barnes, C.; Barreto, J.; Bartlett, J. F.; Bassler, U.; Bauer, D.; Beale, S.; Bean, A.; Begalli, M.; Begel, M.; Belanger-Champagne, C.; Bellantoni, L.; Bellavance, A.; Benitez, J. A.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Berntzon, L.; Bertram, I.; Besançon, M.; Beuselinck, R.; Bezzubov, V. A.; Bhat, P. C.; Bhatnagar, V.; Binder, M.; Biscarat, C.; Blackler, I.; Blazey, G.; Blekman, F.; Blessing, S.; Bloch, D.; Bloom, K.; Boehnlein, A.; Boline, D.; Bolton, T. A.; Boos, E. E.; Borissov, G.; Bos, K.; Bose, T.; Brandt, A.; Brock, R.; Brooijmans, G.; Bross, A.; Brown, D.; Buchanan, N. J.; Buchholz, D.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Burke, S.; Burnett, T. H.; Busato, E.; Buszello, C. P.; Butler, J. M.; Calfayan, P.; Calvet, S.; Cammin, J.; Caron, S.; Carvalho, W.; Casey, B. C. K.; Cason, N. M.; Castilla-Valdez, H.; Chakrabarti, S.; Chakraborty, D.; Chan, K.; Chan, K. M.; Chandra, A.; Charles, F.; Cheu, E.; Chevallier, F.; Cho, D. K.; Choi, S.; Choudhary, B.; Christofek, L.; Christoudias, T.; Claes, D.; Clément, B.; Clément, C.; Coadou, Y.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M.-C.; Cox, B.; Crépé-Renaudin, S.; Cutts, D.; Ćwiok, M.; da Motta, H.; Das, A.; Davies, B.; Davies, G.; de, K.; de Jong, P.; de Jong, S. J.; de La Cruz-Burelo, E.; de Oliveira Martins, C.; Degenhardt, J. D.; Déliot, F.; Demarteau, M.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Diehl, H. T.; Diesburg, M.; Doidge, M.; Dominguez, A.; Dong, H.; Dudko, L. V.; Duflot, L.; Dugad, S. R.; Duggan, D.; Duperrin, A.; Dyer, J.; Dyshkant, A.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Eno, S.; Ermolov, P.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Ferapontov, A. V.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Ford, M.; Fortner, M.; Fox, H.; Fu, S.; Fuess, S.; Gadfort, T.; Galea, C. F.; Gallas, E.; Galyaev, E.; Garcia, C.; Garcia-Bellido, A.; Gavrilov, V.; Gay, P.; Geist, W.; Gelé, D.; Gerber, C. E.; Gershtein, Y.; Gillberg, D.; Ginther, G.; Gollub, N.; Gómez, B.; Goussiou, A.; Grannis, P. D.; Greenlee, H.; Greenwood, Z. D.; Gregores, E. M.; Grenier, G.; Gris, Ph.; Grivaz, J.-F.; Grohsjean, A.; Grünendahl, S.; Grünewald, M. W.; Guo, F.; Guo, J.; Gutierrez, G.; Gutierrez, P.; Haas, A.; Hadley, N. J.; Haefner, P.; Hagopian, S.; Haley, J.; Hall, I.; Hall, R. E.; Han, L.; Hanagaki, K.; Hansson, P.; Harder, K.; Harel, A.; Harrington, R.; Hauptman, J. M.; Hauser, R.; Hays, J.; Hebbeker, T.; Hedin, D.; Hegeman, J. G.; Heinmiller, J. M.; Heinson, A. P.; Heintz, U.; Hensel, C.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hobbs, J. D.; Hoeneisen, B.; Hoeth, H.; Hohlfeld, M.; Hong, S. J.; Hooper, R.; Houben, P.; Hu, Y.; Hubacek, Z.; Hynek, V.; Iashvili, I.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffré, M.; Jain, S.; Jakobs, K.; Jarvis, C.; Jenkins, A.; Jesik, R.; Johns, K.; Johnson, C.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Juste, A.; Käfer, D.; Kahn, S.; Kajfasz, E.; Kalinin, A. M.; Kalk, J. M.; Kalk, J. R.; Kappler, S.; Karmanov, D.; Kasper, J.; Kasper, P.; Katsanos, I.; Kau, D.; Kaur, R.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. M.; Khatidze, D.; Kim, H.; Kim, T. J.; Kirby, M. H.; Klima, B.; Kohli, J. M.; Konrath, J.-P.; Kopal, M.; Korablev, V. M.; Kotcher, J.; Kothari, B.; Koubarovsky, A.; Kozelov, A. V.; Krop, D.; Kryemadhi, A.; Kuhl, T.; Kumar, A.; Kunori, S.; Kupco, A.; Kurča, T.; Kvita, J.; Lam, D.; Lammers, S.; Landsberg, G.; Lazoflores, J.; Lebrun, P.; Lee, W. M.; Leflat, A.; Lehner, F.; Lesne, V.; Leveque, J.; Lewis, P.; Li, J.; Li, L.; Li, Q. Z.; Lietti, S. M.; Lima, J. G. R.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, Z.; Lobo, L.; Lobodenko, A.; Lokajicek, M.; Lounis, A.; Love, P.; Lubatti, H. J.; Lynker, M.; Lyon, A. L.; Maciel, A. K. A.; Madaras, R. J.; Mättig, P.; Magass, C.; Magerkurth, A.; Makovec, N.; Mal, P. K.; Malbouisson, H. B.; Malik, S.; Malyshev, V. L.; Mao, H. S.; Maravin, Y.; Martin, B.; McCarthy, R.; Melnitchouk, A.; Mendes, A.; Mendoza, L.; Mercadante, P. G.; Merkin, M.; Merritt, K. W.; Meyer, A.; Meyer, J.; Michaut, M.; Miettinen, H.; Millet, T.; Mitrevski, J.; Molina, J.; Mommsen, R. K.; Mondal, N. K.; Monk, J.; Moore, R. W.; Moulik, T.; Muanza, G. S.; Mulders, M.; Mulhearn, M.; Mundal, O.; Mundim, L.; Nagy, E.; Naimuddin, M.; Narain, M.; Naumann, N. A.; Neal, H. A.; Negret, J. P.; Neustroev, P.; Nilsen, H.; Noeding, C.; Nomerotski, A.; Novaes, S. F.; Nunnemann, T.; O'Dell, V.; O'Neil, D. C.; Obrant, G.; Ochando, C.; Oguri, V.; Oliveira, N.; Onoprienko, D.; Oshima, N.; Osta, J.; Otec, R.; Otero Y Garzón, G. J.; Owen, M.; Padley, P.; Pangilinan, M.; Parashar, N.; Park, S.-J.; Park, S. K.; Parsons, J.; Partridge, R.; Parua, N.; Patwa, A.; Pawloski, G.; Perea, P. M.; Perfilov, M.; Peters, K.; Peters, Y.; Pétroff, P.; Petteni, M.; Piegaia, R.; Piper, J.; Pleier, M.-A.; Podesta-Lerma, P. L. M.; Podstavkov, V. M.; Pogorelov, Y.; Pol, M.-E.; Pompoš, A.; Pope, B. G.; Popov, A. V.; Potter, C.; Prado da Silva, W. L.; Prosper, H. B.; Protopopescu, S.; Qian, J.; Quadt, A.; Quinn, B.; Rangel, M. S.; Rani, K. J.; Ranjan, K.; Ratoff, P. N.; Renkel, P.; Reucroft, S.; Rijssenbeek, M.; Ripp-Baudot, I.; Rizatdinova, F.; Robinson, S.; Rodrigues, R. F.; Royon, C.; Rubinov, P.; Ruchti, R.; Sajot, G.; Sánchez-Hernández, A.; Sanders, M. P.; Santoro, A.; Savage, G.; Sawyer, L.; Scanlon, T.; Schaile, D.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schieferdecker, P.; Schmitt, C.; Schwanenberger, C.; Schwartzman, A.; Schwienhorst, R.; Sekaric, J.; Sengupta, S.; Severini, H.; Shabalina, E.; Shamim, M.; Shary, V.; Shchukin, A. A.; Shivpuri, R. K.; Shpakov, D.; Siccardi, V.; Sidwell, R. A.; Simak, V.; Sirotenko, V.; Skubic, P.; Slattery, P.; Smirnov, D.; Smith, R. P.; Snow, G. R.; Snow, J.; Snyder, S.; Söldner-Rembold, S.; Sonnenschein, L.; Sopczak, A.; Sosebee, M.; Soustruznik, K.; Souza, M.; Spurlock, B.; Stark, J.; Steele, J.; Stolin, V.; Stone, A.; Stoyanova, D. A.; Strandberg, J.; Strandberg, S.; Strang, M. A.; Strauss, M.; Ströhmer, R.; Strom, D.; Strovink, M.; Stutte, L.; Sumowidagdo, S.; Svoisky, P.; Sznajder, A.; Talby, M.; Tamburello, P.; Taylor, W.; Telford, P.; Temple, J.; Tiller, B.; Tissandier, F.; Titov, M.; Tokmenin, V. V.; Tomoto, M.; Toole, T.; Torchiani, I.; Trefzger, T.; Trincaz-Duvoid, S.; Tsybychev, D.; Tuchming, B.; Tully, C.; Tuts, P. M.; Unalan, R.; Uvarov, L.; Uvarov, S.; Uzunyan, S.; Vachon, B.; van den Berg, P. J.; van Eijk, B.; van Kooten, R.; van Leeuwen, W. M.; Varelas, N.; Varnes, E. W.; Vartapetian, A.; Vasilyev, I. A.; Vaupel, M.; Verdier, P.; Vertogradov, L. S.; Verzocchi, M.; Villeneuve-Seguier, F.; Vint, P.; Vlimant, J.-R.; von Toerne, E.; Voutilainen, M.; Vreeswijk, M.; Wahl, H. D.; Wang, L.; Wang, M. H. L. S.; Warchol, J.; Watts, G.; Wayne, M.; Weber, G.; Weber, M.; Weerts, H.; Wenger, A.; Wermes, N.; Wetstein, M.; White, A.; Wicke, D.; Wilson, G. W.; Wimpenny, S. J.; Wobisch, M.; Wood, D. R.; Wyatt, T. R.; Xie, Y.; Yacoob, S.; Yamada, R.; Yan, M.; Yasuda, T.; Yatsunenko, Y. A.; Yip, K.; Yoo, H. D.; Youn, S. W.; Yu, C.; Yu, J.; Yurkewicz, A.; Zatserklyaniy, A.; Zeitnitz, C.; Zhang, D.; Zhao, T.; Zhou, B.; Zhu, J.; Zielinski, M.; Zieminska, D.; Zieminski, A.; Zutshi, V.; Zverev, E. G.

2007-11-01

We search for the production of single top quarks via flavor-changing-neutral-current couplings of a gluon to the top quark and a charm (c) or up (u) quark. We analyze 230pb-1 of lepton+jets data from pp¯ collisions at a center of mass energy of 1.96 TeV collected by the D0 detector at the Fermilab Tevatron Collider. We observe no significant deviation from standard model predictions, and hence set upper limits on the anomalous coupling parameters κgc/Λ and κgu/Λ, where κg define the strength of tcg and tug couplings, and Λ defines the scale of new physics. The limits at 95% C.L. are κgc/Λ<0.15TeV-1 and κgu/Λ<0.037TeV-1.

A New Hybrid Channel Access Scheme for Ad Hoc Networks

National Research Council Canada - National Science Library

Wang, Yu; Garcia-Luna-Aceves, J. J

2002-01-01

Many contention-based channel access schemes have been proposed for multi-hop ad hoc networks in the recent past, and they can be divided into two categories, sender-initiated and receiver-initiated...

History of the research ad hoc committee on 'dissemination of information' and the special ad hoc committee on 'dissemination of information' of the Atomic Energy Society of Japan

Energy Technology Data Exchange (ETDEWEB)

Itabashi, Keizo [Japan Atomic Energy Agency, Intellectual Resources Department, Tokai, Ibaraki (Japan)

2010-06-15

The Research ad hoc committee on 'Dissemination of information' of the Atomic Energy Society of Japan was held 15 times from Oct. 1970 to Mar 1973. After that, The Special ad hoc committee on 'Dissemination of information' of the Atomic Energy Society of Japan was held 115 times from Apr. 1973 to Mar 2009. The history of these two committees is described. Activity report is arranged including the information on change of the member and topics of the meeting, and the minutes. Furthermore, the document list on International Nuclear Information System (INIS) from Japan is included. (author)

History of the research ad hoc committee on 'dissemination of information' and the special ad hoc committee on 'dissemination of information' of the Atomic Energy Society of Japan

International Nuclear Information System (INIS)

Itabashi, Keizo

2010-06-01

The Research ad hoc committee on 'Dissemination of information' of the Atomic Energy Society of Japan was held 15 times from Oct. 1970 to Mar 1973. After that, The Special ad hoc committee on 'Dissemination of information' of the Atomic Energy Society of Japan was held 115 times from Apr. 1973 to Mar 2009. The history of these two committees is described. Activity report is arranged including the information on change of the member and topics of the meeting, and the minutes. Furthermore, the document list on International Nuclear Information System (INIS) from Japan is included. (author)

On the Geometrical Characteristics of Three-Dimensional Wireless Ad Hoc Networks and Their Applications

Directory of Open Access Journals (Sweden)

2006-01-01

Full Text Available In a wireless ad hoc network, messages are transmitted, received, and forwarded in a finite geometrical region and the transmission of messages is highly dependent on the locations of the nodes. Therefore the study of geometrical relationship between nodes in wireless ad hoc networks is of fundamental importance in the network architecture design and performance evaluation. However, most previous works concentrated on the networks deployed in the two-dimensional region or in the infinite three-dimensional space, while in many cases wireless ad hoc networks are deployed in the finite three-dimensional space. In this paper, we analyze the geometrical characteristics of the three-dimensional wireless ad hoc network in a finite space in the framework of random graph and deduce an expression to calculate the distance probability distribution between network nodes that are independently and uniformly distributed in a finite cuboid space. Based on the theoretical result, we present some meaningful results on the finite three-dimensional network performance, including the node degree and the max-flow capacity. Furthermore, we investigate some approximation properties of the distance probability distribution function derived in the paper.

VMQL: A Visual Language for Ad-Hoc Model Querying

DEFF Research Database (Denmark)

Störrle, Harald

2011-01-01

In large scale model based development, analysis level models are more like knowledge bases than engineering artifacts. Their effectiveness depends, to a large degree, on the ability of domain experts to retrieve information from them ad hoc. For large scale models, however, existing query...

Access Point Security Service for wireless ad-hoc communication

NARCIS (Netherlands)

Scholten, Johan; Nijdam, M.

2006-01-01

This paper describes the design and implementation of a security solution for ad-hoc peer-to-peer communication. The security solution is based on a scenario where two wireless devices require secure communication, but share no security relationship a priori. The necessary requirements for the

FRAMEWORK FOR AD HOC NETWORK COMMUNICATION IN MULTI-ROBOT SYSTEMS

Directory of Open Access Journals (Sweden)

Khilda Slyusar

2016-11-01

Full Text Available Assume a team of mobile robots operating in environments where no communication infrastructure like routers or access points is available. The robots have to create a mobile ad hoc network, in that case, it provides communication on peer-to-peer basis. The paper gives an overview of existing solutions how to route messages in such ad hoc networks between robots that are not directly connected and introduces a design of a software framework for realization of such communication. Feasibility of the proposed framework is shown on the example of distributed multi-robot exploration of an a priori unknown environment. Testing of developed functionality in an exploration scenario is based on results of several experiments with various input conditions of the exploration process and various sizes of a team and is described herein.

A Novel Routing Algorithm for Vehicular Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Raúl Aquino Santos

2008-01-01

Full Text Available Este trabajo examina la importancia de las redes inalámbricas ad hoc y el algoritmo de enrutamiento con inundación basada en grupos (LORA-CBF para la comunicación inter-vehicular con la finalidad de optimizar el flujo de tráfico e incrementar la seguridad en las autopistas. Se discute el algoritmo de enrutamiento LORA-CBF y se presentan los resultados de simulaciones realizadas en OPNET de una autopista con alta movilidad vehicular. Primero, el modelo de simulación propuesto se valida a pequeña escala con resultados experimentales. Posteriormente, se emplean simulaciones de nuestro modelo comparándolos con Ad Hoc On-Demand Distance Vector (AODV y Dynamic Source Routing (DSR. Finalmente, se emplea un modelo de tráfico microscópico desarrollado en OPNET para simular la movilidad de 250 vehículos en una autopista y se aplica el algoritmo de enrutamiento LORA-CBF en un escenario vehicular.

simulate_CAT: A Computer Program for Post-Hoc Simulation for Computerized Adaptive Testing

Directory of Open Access Journals (Sweden)

İlker Kalender

2015-06-01

Full Text Available This paper presents a computer software developed by the author. The software conducts post-hoc simulations for computerized adaptive testing based on real responses of examinees to paper and pencil tests under different parameters that can be defined by user. In this paper, short information is given about post-hoc simulations. After that, the working principle of the software is provided and a sample simulation with required input files is shown. And last, output files are described

Report of the review committee on evaluation of the R and D subjects in the field of nuclear safety research

International Nuclear Information System (INIS)

2000-09-01

On the basis of the JAERI's Basic Guidelines for the Research Evaluation Methods and the Practices Manuals of the Institution Evaluation Committee and Research Evaluation Committee, the Ad Hoc Review Committee on Nuclear Safety Research composed of twelve experts was set up under the Research Evaluation Committee of the JAERI in order to review the R and D subjects to be implemented for five years starting in FY2000 in the Nuclear Safety Research Center (Department of Reactor Safety Research, Department of Fuel Cycle Safety Research and Department of Safety Research Technical Support). The Ad Hoc Review Committee meeting was held on January 20, 2000. According to the review methods including review items, points of review and review criteria, determined by the Research Evaluation Committee, the review was conducted based on the research plan documents submitted in advance and presentations by the Department Directors. The review report was submitted to the Research Evaluation Committee for further review and discussions in its meeting held on August 31, 2000. The Research Evaluation Committee recognized the review results as appropriate. This report describes the review results. (author)

UMDR: Multi-Path Routing Protocol for Underwater Ad Hoc Networks with Directional Antenna

Science.gov (United States)

Yang, Jianmin; Liu, Songzuo; Liu, Qipei; Qiao, Gang

2018-01-01

This paper presents a new routing scheme for underwater ad hoc networks based on directional antennas. Ad hoc networks with directional antennas have become a hot research topic because of space reuse may increase networks capacity. At present, researchers have applied traditional self-organizing routing protocols (such as DSR, AODV) [1] [2] on this type of networks, and the routing scheme is based on the shortest path metric. However, such routing schemes often suffer from long transmission delays and frequent link fragmentation along the intermediate nodes of the selected route. This is caused by a unique feature of directional transmission, often called as “deafness”. In this paper, we take a different approach to explore the advantages of space reuse through multipath routing. This paper introduces the validity of the conventional routing scheme in underwater ad hoc networks with directional antennas, and presents a special design of multipath routing algorithm for directional transmission. The experimental results show a significant performance improvement in throughput and latency.

Improving VANETs Connectivity with a Totally Ad Hoc Living Mobile Backbone

Directory of Open Access Journals (Sweden)

Joilson Alves Junior

2015-01-01

Full Text Available The vehicular ad hoc network (VANET for intelligent transportation systems is an emerging concept to improve transportation security, reliability, and management. The network behavior can be totally different in topological aspects because of the mobility of vehicular nodes. The topology can be fully connected when the flow of vehicles is high and may have low connectivity or be invalid when the flow of vehicles is low or unbalanced. In big cities, the metropolitan buses that travel on exclusive lanes may be used to set up a metropolitan vehicular data network (backbone, raising the connectivity among the vehicles. Therefore, this paper proposes the implementation of a living mobile backbone, totally ad hoc (MOB-NET, which will provide infrastructure and raise the network connectivity. In order to show the viability of MOB-NET, statistical analyses were made with real data of express buses that travel through exclusive lanes, besides evaluations through simulations and analytic models. The statistic, analytic, and simulation results prove that the buses that travel through exclusive lanes can be used to build a communication network totally ad hoc and provide connectivity in more than 99% of the time, besides raising the delivery rate up to 95%.

Collaboration Layer for Robots in Mobile Ad-hoc Networks

DEFF Research Database (Denmark)

Borch, Ole; Madsen, Per Printz; Broberg, Jacob Honor´e

2009-01-01

In many applications multiple robots in Mobile Ad-hoc Networks are required to collaborate in order to solve a task. This paper shows by proof of concept that a Collaboration Layer can be modelled and designed to handle the collaborative communication, which enables robots in small to medium size...

Recommended research program for improving seismic safety of light-water nuclear power plants

International Nuclear Information System (INIS)

1979-04-01

Recommendations are presented for research areas concerned with seismic safety. These recommendations are based on an analysis of the answers to a questionnaire which was sent to over 80 persons working in the area of seismic safety of nuclear power plants. In addition to the answers of the 55 questionnaires which were received, the recommendations are based on ideas expressed at a meeting of an ad hoc group of professionals formed by Sandia, review of literature, current research programs, and engineering judgement

Distributed optimization of a multisubchannel Ad Hoc cognitive radio network

KAUST Repository

Leith, Alex

2012-05-01

In this paper, we study the distributed-duality-based optimization of a multisubchannel ad hoc cognitive radio network (CRN) that coexists with a multicell primary radio network (PRN). For radio resource allocation in multiuser orthogonal frequency-division multiplexing (MU-OFDM) systems, the orthogonal-access-based exclusive subchannel assignment (ESA) technique has been a popular method, but it is suboptimal in ad hoc networks, because nonorthogonal access between multiple secondary-user links by using shared subchannel assignment (SSA) can bring a higher weighted sum rate. We utilize the Lagrangian dual composition tool and design low-complexity near-optimal SSA resource allocation methods, assuming practical discrete-rate modulation and that the CRN-to-PRN interference constraint has to strictly be satisfied. However, available SSA methods for CRNs are either suboptimal or involve high complexity and suffer from slow convergence. To address this problem, we design fast-convergence SSA duality schemes and introduce several novel methods to increase the speed of convergence and to satisfy various system constraints with low complexity. For practical implementation in ad hoc CRNs, we design distributed-duality schemes that involve only a small number of CRN local information exchanges for dual update. The effects of many system parameters are presented through simulation results, which show that the near-optimal SSA duality scheme can perform significantly better than the suboptimal ESA duality and SSA-iterative waterfilling schemes and that the performance loss of the distributed schemes is small, compared with their centralized counterparts. © 2012 IEEE.

Minimizing Broadcast Expenses in Clustered Ad-hoc Networks

Directory of Open Access Journals (Sweden)

S. Zeeshan Hussain

2018-01-01

Full Text Available One way to minimize the broadcast expenses of routing protocols is to cluster the network. In clustered ad-hoc networks, all resources can be managed easily by resolving scalability issues. However, blind query broadcast is a major issue that leads to the broadcast storm problem in clustered ad-hoc networks. This query broadcast is done to carry out the route-search task that leads to the unnecessary propagation of route-query even after route has been found. Hence, this query propagation poses the problem of congestion in the network. In particular this motivates us to propose a query-control technique in such networks which works based on broadcast repealing. A huge amount of work has been devoted to propose the query control broadcasting techniques. However, such techniques used in traditional broadcasting mechanisms need to be properly extended for use in the cluster based routing architecture. In this paper, query-control technique is proposed for cluster based routing technique to reduce the broadcast expenses. Finally, we report some experiments which compare the proposed technique to other commonly used techniques including standard one-class AODV that follows TTL-sequence based broadcasting technique.

Service for fault tolerance in the Ad Hoc Networks based on Multi Agent Systems

Directory of Open Access Journals (Sweden)

Ghalem Belalem

2011-02-01

Full Text Available The Ad hoc networks are distributed networks, self-organized and does not require infrastructure. In such network, mobile infrastructures are subject of disconnections. This situation may concern a voluntary or involuntary disconnection of nodes caused by the high mobility in the Ad hoc network. In these problems we are trying through this work to contribute to solving these problems in order to ensure continuous service by proposing our service for faults tolerance based on Multi Agent Systems (MAS, which predict a problem and decision making in relation to critical nodes. Our work contributes to study the prediction of voluntary and involuntary disconnections in the Ad hoc network; therefore we propose our service for faults tolerance that allows for effective distribution of information in the Network by selecting some objects of the network to be duplicates of information.

Capacity, delay and mobility in wireless ad-hoc networks

NARCIS (Netherlands)

Bansal, N.; Liu, Z.

2003-01-01

Network throughput and packet delay are two important parameters in the design and the evaluation of routing protocols for ad-hoc networks. While mobility has been shown to increase the capacity of a network, it is not clear whether the delay can be kept low without trading off the throughput. We

New data on health and safety at work in the EU27

NARCIS (Netherlands)

Venema, A.; Geuskens, G.; Heuvel, S. van den

2011-01-01

To study the occurrence of accidents resulting in injury and work-related health problems in the past 12 months in workers aged 15 to 64 years in the EU27 the Labour Force Survey (LFS) in Europe included in 2007 an ad hoc module on health and safety at work. The module consisted of four variables on

On-Demand Routing in Multi-hop Wireless Mobile Ad Hoc Networks

National Research Council Canada - National Science Library

Maltz, David A

2001-01-01

.... Routing protocols used in ad hoc networks must automatically adjust to environments that can vary between the extremes of high mobility with low bandwidth, and low mobility with high bandwidth...

Throughput and Fairness of Collision Avoidance Protocols in Ad Hoc Networks

National Research Council Canada - National Science Library

Garcia-Luna-Aceves, J. J; Wang, Yu

2004-01-01

.... In Section 1, The authors present an analytical modeling to derive the saturation throughput of these sender-initiated collision avoidance protocols in multi-hop ad hoc networks with nodes randomly...

PNNI routing support for ad hoc mobile networking: The multilevel case

Energy Technology Data Exchange (ETDEWEB)

Martinez, L.; Sholander, P.; Tolendino, L.

1998-01-01

This contribution extends the Outside Nodal Hierarchy List (ONHL) procedures described in ATM Forum Contributions 97-0766 and 97-0933. These extensions allow multiple mobile networks to form either an ad hoc network or an extension of a fixed PNNI infrastructure. A previous contribution (97-1073) covered the simplest case where the top-most Logical Group Nodes (LGNs), in those mobile networks, all resided at the same level in a PNNI hierarchy. This contribution covers the more general case wherein those top-most LGNs may reside at different PNNI hierarchy levels. Both of the SNL contributions consider flat ad hoc network architectures in the sense that each mobile network always participates in the PNNI hierarchy at the pre-configured level of its top-most LGN.

Intelligent routing protocol for ad hoc wireless network

Science.gov (United States)

Peng, Chaorong; Chen, Chang Wen

2006-05-01

A novel routing scheme for mobile ad hoc networks (MANETs), which combines hybrid and multi-inter-routing path properties with a distributed topology discovery route mechanism using control agents is proposed in this paper. In recent years, a variety of hybrid routing protocols for Mobile Ad hoc wireless networks (MANETs) have been developed. Which is proactively maintains routing information for a local neighborhood, while reactively acquiring routes to destinations beyond the global. The hybrid protocol reduces routing discovery latency and the end-to-end delay by providing high connectivity without requiring much of the scarce network capacity. On the other side the hybrid routing protocols in MANETs likes Zone Routing Protocol still need route "re-discover" time when a route between zones link break. Sine the topology update information needs to be broadcast routing request on local zone. Due to this delay, the routing protocol may not be applicable for real-time data and multimedia communication. We utilize the advantages of a clustering organization and multi-routing path in routing protocol to achieve several goals at the same time. Firstly, IRP efficiently saves network bandwidth and reduces route reconstruction time when a routing path fails. The IRP protocol does not require global periodic routing advertisements, local control agents will automatically monitor and repair broke links. Secondly, it efficiently reduces congestion and traffic "bottlenecks" for ClusterHeads in clustering network. Thirdly, it reduces significant overheads associated with maintaining clusters. Fourthly, it improves clusters stability due to dynamic topology changing frequently. In this paper, we present the Intelligent Routing Protocol. First, we discuss the problem of routing in ad hoc networks and the motivation of IRP. We describe the hierarchical architecture of IRP. We describe the routing process and illustrate it with an example. Further, we describe the control manage

ENERGY EFFICIENT ROUTING PROTOCOLS FOR WIRELESS AD HOC NETWORKS – A SURVEY

Directory of Open Access Journals (Sweden)

K. Sankar

2012-06-01

Full Text Available Reducing energy consumption, primarily with the goal of extending the lifetime of battery-powered devices, has emerged as a fundamental challenge in wireless communication. The performance of the medium access control (MAC scheme not only has a fairly significant end-result on the behaviour of the routing approach employed, but also on the energy consumption of the wireless network interface card (NIC. We investigate the inadequacies of the MAC schemes designed for ad hoc wireless networks in the context of power awareness herein. The topology changes due to uncontrollable factors such as node mobility, weather, interference, noise, as well as on controllable parameters such as transmission power and antenna direction results in significant amount of energy loss. Controlling rapid topology changes by minimizing the maximum transmission power used in ad hoc wireless networks, while still maintaining networks connectivity can prolong battery life and hence network lifetime considerably. In addition, we systematically explore the potential energy consumption pitfalls of non–power-based and power based routing schemes. We suggest a thorough energy-based performance survey of energy aware routing protocols for wireless mobile ad-hoc networks. We also present the statistical performance metrics measured by our simulations.

Research on Propagation Model of Malicious Programs in Ad Hoc Wireless Network

Directory of Open Access Journals (Sweden)

Weimin GAO

2014-01-01

Full Text Available Ad Hoc wireless network faces more security threats than traditional network due to its P2P system structure and the limited node resources. In recent years, malicious program has become one of the most important researches on international network security and information security. The research of malicious programs on wireless network has become a new research hotspot in the field of malicious programs. This paper first analyzed the Ad Hoc network system structure, security threats, the common classification of malicious programs and the bionic propagation model. Then starting from the differential equations of the SEIR virus propagation model, the question caused by introducing the SEIR virus propagation model in Ad Hoc wireless network was analyzed. This paper improved the malicious program propagation model through introducing the network topology features and concepts such as immunization delay, and designed an improved algorithm combined with the dynamic evolution of malware propagation process. Considering of the network virus propagation characteristics, network characteristics and immunization strategy to improve simulation model experiment analysis, the experimental results show that both the immunization strategy and the degrees of node can affect the propagation of malicious program.

Exploiting Mobile Ad Hoc Networking and Knowledge Generation to Achieve Ambient Intelligence

Directory of Open Access Journals (Sweden)

Anna Lekova

2012-01-01

Full Text Available Ambient Intelligence (AmI joins together the fields of ubiquitous computing and communications, context awareness, and intelligent user interfaces. Energy, fault-tolerance, and mobility are newly added dimensions of AmI. Within the context of AmI the concept of mobile ad hoc networks (MANETs for “anytime and anywhere” is likely to play larger roles in the future in which people are surrounded and supported by small context-aware, cooperative, and nonobtrusive devices that will aid our everyday life. The connection between knowledge generation and communication ad hoc networking is symbiotic—knowledge generation utilizes ad hoc networking to perform their communication needs, and MANETs will utilize the knowledge generation to enhance their network services. The contribution of the present study is a distributed evolving fuzzy modeling framework (EFMF to observe and categorize relationships and activities in the user and application level and based on that social context to take intelligent decisions about MANETs service management. EFMF employs unsupervised online one-pass fuzzy clustering method to recognize nodes' mobility context from social scenario traces and ubiquitously learn “friends” and “strangers” indirectly and anonymously.

Encaged molecules in external electric fields: A molecular "tug-of-war"

Science.gov (United States)

Gurav, Nalini D.; Gejji, Shridhar P.; Bartolotti, Libero J.; Pathak, Rajeev K.

2016-08-01

Response of polar molecules CH3OH and H2O2 and a non-polar molecule, CO2, as "guests" encapsulated in the dodecahedral water cage (H2O)20 "host," to an external, perturbative electric field is investigated theoretically. We employ the hybrid density-functionals M06-2X and ωB97X-D incorporating the effects of damped dispersion, in conjunction with the maug-cc-pVTZ basis set, amenable for a hydrogen bonding description. While the host cluster (cage) tends to confine the embedded guest molecule through cooperative hydrogen bonding, the applied electric field tends to rupture the cluster-composite by stretching it; these two competitive effects leading to a molecular "tug-of-war." The composite remains stable up to a maximal sustainable threshold electric field, beyond which, concomitant with the vanishing of the HOMO-LUMO gap, the field wins over and the cluster breaks down. The electric-field effects are gauged in terms of the changes in the molecular geometry of the confined species, interaction energy, molecular electrostatic potential surfaces, and frequency shifts of characteristic normal vibrations in the IR regime. Interestingly, beyond the characteristic threshold electric field, the labile, distorted host cluster fragmentizes, and the guest molecule still tethered to a remnant fragment, an effect attributed to the underlying hydrogen-bonded networks.

Safety and efficacy of anticoagulation for secondary stroke prevention in atrial fibrillation patients: The AMADEUS trial

NARCIS (Netherlands)

Lane, D.A.; Kamphuisen, P.W.; Minini, P.; Buller, H.R.; Lip, G.Y.H.

2010-01-01

ackground: Patients with atrial fibrillation (AF) and previous ischemic stroke are at high risk of recurrent stroke, but are also perceived to be at increased bleeding risk while treated with anticoagulants. Methods: Post-hoc analyses examined the efficacy and safety of anticoagulation of 4576 AF

Age and workers' perceptions of workplace safety: a comparative study.

Science.gov (United States)

Gyekye, Seth Ayim; Salminen, Simo

2009-01-01

The study examined the relationship between age and (i) safety perception; (ii) job satisfaction; (iii) compliance with safety management policies; and (iv) accident frequency. Participants were Ghanaian industrial workers (N=320) categorized into 4 age groups: 19-29 years; 30-39 years; 40-50 years; and 51 years and above. Workplace safety perception was assessed with Hayes, Perander, Smecko, and Trask's (1998) 50-item Work Safety Scale (WSS): a scale that effectively captures the dimensions identified by safety experts to influence perceptions of workplace safety. ANOVA was used to test for differences in the mean scores of the 4 groups. Post Hoc analysis revealed differences of statistical significance between the 2 younger cohorts and the 2 older cohorts. The results indicated a positive association between age and safety perception. Older workers had the best perceptions on safety, indicated the highest level of job satisfaction, were the most compliant with safety procedures, and recorded the lowest accident involvement rate. From a practical perspective, understanding age-related perceptions of workplace safety would benefit management's decisions regarding workers' adaptability, general work effectiveness, accident frequency, implementation of safety management policies, and handling of age-related accident characteristics.

Safety research in the field of energy production. Plan for continued Nordic projects

Energy Technology Data Exchange (ETDEWEB)

Ahlstroem, P E [Statens Vattenfallsverk, Stockholm (Sweden); Berg, J [Institutt for Atomenergi, Kjeller (Norway); Eckered, T [Statens Kaernkraftinspektion, Stockholm (Sweden)

1980-01-01

NGS, an ad hoc group of the Nordic Co-ordination Committee for Atomic Energy, has prepared this survey of proposed cooperative projects as a continuation of previous projects. New areas to be given priority are:- reactor safety, environmental effects in energy production and human reliability. Continued projects are:- quality assurance, radioactive waste and radioecology. (JIW)

QoS Routing in Ad-Hoc Networks Using GA and Multi-Objective Optimization

Directory of Open Access Journals (Sweden)

Admir Barolli

2011-01-01

Full Text Available Much work has been done on routing in Ad-hoc networks, but the proposed routing solutions only deal with the best effort data traffic. Connections with Quality of Service (QoS requirements, such as voice channels with delay and bandwidth constraints, are not supported. The QoS routing has been receiving increasingly intensive attention, but searching for the shortest path with many metrics is an NP-complete problem. For this reason, approximated solutions and heuristic algorithms should be developed for multi-path constraints QoS routing. Also, the routing methods should be adaptive, flexible, and intelligent. In this paper, we use Genetic Algorithms (GAs and multi-objective optimization for QoS routing in Ad-hoc Networks. In order to reduce the search space of GA, we implemented a search space reduction algorithm, which reduces the search space for GAMAN (GA-based routing algorithm for Mobile Ad-hoc Networks to find a new route. We evaluate the performance of GAMAN by computer simulations and show that GAMAN has better behaviour than GLBR (Genetic Load Balancing Routing.

TMAP ad hoc Working Group Fish Progress report 2007

NARCIS (Netherlands)

Bolle, L.J.; Damm, U.; Diederichs, B.; Jager, Z.; Overzee, van H.M.J.

2007-01-01

Building on previous work done by the TMAP ad hoc Working Group Fish, a meeting and a workshop were held in Hamburg in June and October 2007. The most important aim of both was to come to an agreement on how to proceed with the data preparations and analyses, and to facilitate the exchange of data

Optimal design of cluster-based ad-hoc networks using probabilistic solution discovery

International Nuclear Information System (INIS)

Cook, Jason L.; Ramirez-Marquez, Jose Emmanuel

2009-01-01

The reliability of ad-hoc networks is gaining popularity in two areas: as a topic of academic interest and as a key performance parameter for defense systems employing this type of network. The ad-hoc network is dynamic and scalable and these descriptions are what attract its users. However, these descriptions are also synonymous for undefined and unpredictable when considering the impacts to the reliability of the system. The configuration of an ad-hoc network changes continuously and this fact implies that no single mathematical expression or graphical depiction can describe the system reliability-wise. Previous research has used mobility and stochastic models to address this challenge successfully. In this paper, the authors leverage the stochastic approach and build upon it a probabilistic solution discovery (PSD) algorithm to optimize the topology for a cluster-based mobile ad-hoc wireless network (MAWN). Specifically, the membership of nodes within the back-bone network or networks will be assigned in such as way as to maximize reliability subject to a constraint on cost. The constraint may also be considered as a non-monetary cost, such as weight, volume, power, or the like. When a cost is assigned to each component, a maximum cost threshold is assigned to the network, and the method is run; the result is an optimized allocation of the radios enabling back-bone network(s) to provide the most reliable network possible without exceeding the allowable cost. The method is intended for use directly as part of the architectural design process of a cluster-based MAWN to efficiently determine an optimal or near-optimal design solution. It is capable of optimizing the topology based upon all-terminal reliability (ATR), all-operating terminal reliability (AoTR), or two-terminal reliability (2TR)

A-priori and post-hoc segmentation in the design of healthy eating campaigns

DEFF Research Database (Denmark)

Kazbare, Laura; van Trijp, Hans C. M.; Eskildsen, Jacob Kjær

2010-01-01

. Although such practice may be justifiable from the practical point of view, it is unclear how effective these implicit segmentations are. In this study the authors argue that  it is important to transcend demographic boundaries and to further segment demographic groups. A study with 13-15-year-old...... and a post-hoc segmentation. The results of the study show that it is useful and also ethical to differentiate people using segmentation methods, since it facilitates reaching more vulnerable segments of society that in general resist change. It also demonstrates that post-hoc segmentation is more helpful...

An Ad-Hoc Adaptive Pilot Model for Pitch Axis Gross Acquisition Tasks

Science.gov (United States)

Hanson, Curtis E.

2012-01-01

An ad-hoc algorithm is presented for real-time adaptation of the well-known crossover pilot model and applied to pitch axis gross acquisition tasks in a generic fighter aircraft. Off-line tuning of the crossover model to human pilot data gathered in a fixed-based high fidelity simulation is first accomplished for a series of changes in aircraft dynamics to provide expected values for model parameters. It is shown that in most cases, for this application, the traditional crossover model can be reduced to a gain and a time delay. The ad-hoc adaptive pilot gain algorithm is shown to have desirable convergence properties for most types of changes in aircraft dynamics.

The Ad Hoc process to strengthen the framework convention on climate change

Energy Technology Data Exchange (ETDEWEB)

Ramakrishna, K.; Deutz, A.M.; Jacobsen, L.A. [eds.

1995-11-01

The Woods Hole Research Center convened an International Conference on The Ad Hoc Process to Strengthen the Framework Convention on Climate Change in Woods Hole, MA, on October 7-9, 1995. The conference was conducted to examine the prospects for successful adoption of a protocol to the Framework Convention on Climate Change by 1997. In preparation for the Second session of the Ad Hoc Group on the Berlin Mandate, several governmental and nongovernmental representatives met in Woods Hole to discuss the process and possible outcome of the Berlin Mandate negotiations for a protocol or other legal instrument to strengthen the Convention. The conference was by invitation and all participants attended in their personal capacities.

3VSR: Three Valued Secure Routing for Vehicular Ad Hoc Networks using Sensing Logic in Adversarial Environment

Directory of Open Access Journals (Sweden)

Muhammad Sohail

2018-03-01

Full Text Available Today IoT integrate thousands of inter networks and sensing devices e.g., vehicular networks, which are considered to be challenging due to its high speed and network dynamics. The goal of future vehicular networks is to improve road safety, promote commercial or infotainment products and to reduce the traffic accidents. All these applications are based on the information exchange among nodes, so not only reliable data delivery but also the authenticity and credibility of the data itself are prerequisite. To cope with the aforementioned problem, trust management come up as promising candidate to conduct node’s transaction and interaction management, which requires distributed mobile nodes cooperation for achieving design goals. In this paper, we propose a trust-based routing protocol i.e., 3VSR (Three Valued Secure Routing, which extends the widely used AODV (Ad hoc On-demand Distance Vector routing protocol and employs the idea of Sensing Logic-based trust model to enhance the security solution of VANET (Vehicular Ad-Hoc Network. The existing routing protocol are mostly based on key or signature-based schemes, which off course increases computation overhead. In our proposed 3VSR, trust among entities is updated frequently by means of opinion derived from sensing logic due to vehicles random topologies. In 3VSR the theoretical capabilities are based on Dirichlet distribution by considering prior and posterior uncertainty of the said event. Also by using trust recommendation message exchange, nodes are able to reduce computation and routing overhead. The simulated results shows that the proposed scheme is secure and practical.

3VSR: Three Valued Secure Routing for Vehicular Ad Hoc Networks using Sensing Logic in Adversarial Environment.

Science.gov (United States)

Sohail, Muhammad; Wang, Liangmin

2018-03-14

Today IoT integrate thousands of inter networks and sensing devices e.g., vehicular networks, which are considered to be challenging due to its high speed and network dynamics. The goal of future vehicular networks is to improve road safety, promote commercial or infotainment products and to reduce the traffic accidents. All these applications are based on the information exchange among nodes, so not only reliable data delivery but also the authenticity and credibility of the data itself are prerequisite. To cope with the aforementioned problem, trust management come up as promising candidate to conduct node's transaction and interaction management, which requires distributed mobile nodes cooperation for achieving design goals. In this paper, we propose a trust-based routing protocol i.e., 3VSR (Three Valued Secure Routing), which extends the widely used AODV (Ad hoc On-demand Distance Vector) routing protocol and employs the idea of Sensing Logic-based trust model to enhance the security solution of VANET (Vehicular Ad-Hoc Network). The existing routing protocol are mostly based on key or signature-based schemes, which off course increases computation overhead. In our proposed 3VSR, trust among entities is updated frequently by means of opinion derived from sensing logic due to vehicles random topologies. In 3VSR the theoretical capabilities are based on Dirichlet distribution by considering prior and posterior uncertainty of the said event. Also by using trust recommendation message exchange, nodes are able to reduce computation and routing overhead. The simulated results shows that the proposed scheme is secure and practical.

ON SECURE FULL DUPLEX COMMUNICATION IN MOBILE AD HOC NETWORK

OpenAIRE

S. C. Dutta; Sudha Singh; D. K. Singh

2013-01-01

This paper is to establish Ad Hoc network in mobile phones and start fully secured full duplex communication in any situation. This type of communication will be cost effective and it will be fastest way of communication in case of any server failure or server error.

An Economic Framework for Resource Allocation in Ad-hoc Grids

NARCIS (Netherlands)

Pourebrahimi, B.

2009-01-01

In this dissertation, we present an economic framework to study and develop different market-based mechanisms for resource allocation in an ad-hoc Grid. Such an economic framework helps to understand the impact of certain choices and explores what are the suitable mechanisms from Grid user/owner

A Tool for Visualizing Mobile Ad-Hoc Network Topology Definitions Files

National Research Council Canada - National Science Library

Nguyen, Binh Q

2006-01-01

This report documents a research and development effort that the U.S. Army Research Laboratory conducted in FY05 in support of the building of an emulated tactical mobile ad hoc network (MANET) research test bed...

Capacity of Wireless Ad Hoc Networks with Opportunistic Collaborative Communications

Directory of Open Access Journals (Sweden)

Simeone O

2007-01-01

Full Text Available Optimal multihop routing in ad hoc networks requires the exchange of control messages at the MAC and network layer in order to set up the (centralized optimization problem. Distributed opportunistic space-time collaboration (OST is a valid alternative that avoids this drawback by enabling opportunistic cooperation with the source at the physical layer. In this paper, the performance of OST is investigated. It is shown analytically that opportunistic collaboration outperforms (centralized optimal multihop in case spatial reuse (i.e., the simultaneous transmission of more than one data stream is not allowed by the transmission protocol. Conversely, in case spatial reuse is possible, the relative performance between the two protocols has to be studied case by case in terms of the corresponding capacity regions, given the topology and the physical parameters of network at hand. Simulation results confirm that opportunistic collaborative communication is a promising paradigm for wireless ad hoc networks that deserves further investigation.

Capacity of Wireless Ad Hoc Networks with Opportunistic Collaborative Communications

Directory of Open Access Journals (Sweden)

O. Simeone

2007-03-01

Full Text Available Optimal multihop routing in ad hoc networks requires the exchange of control messages at the MAC and network layer in order to set up the (centralized optimization problem. Distributed opportunistic space-time collaboration (OST is a valid alternative that avoids this drawback by enabling opportunistic cooperation with the source at the physical layer. In this paper, the performance of OST is investigated. It is shown analytically that opportunistic collaboration outperforms (centralized optimal multihop in case spatial reuse (i.e., the simultaneous transmission of more than one data stream is not allowed by the transmission protocol. Conversely, in case spatial reuse is possible, the relative performance between the two protocols has to be studied case by case in terms of the corresponding capacity regions, given the topology and the physical parameters of network at hand. Simulation results confirm that opportunistic collaborative communication is a promising paradigm for wireless ad hoc networks that deserves further investigation.

An Effective Approach for Mobile ad hoc Network via I-Watchdog Protocol

Directory of Open Access Journals (Sweden)

Nidhi Lal

2014-12-01

Full Text Available Mobile ad hoc network (MANET is now days become very famous due to their fixed infrastructure-less quality and dynamic nature. They contain a large number of nodes which are connected and communicated to each other in wireless nature. Mobile ad hoc network is a wireless technology that contains high mobility of nodes and does not depend on the background administrator for central authority, because they do not contain any infrastructure. Nodes of the MANET use radio wave for communication and having limited resources and limited computational power. The Topology of this network is changing very frequently because they are distributed in nature and self-configurable. Due to its wireless nature and lack of any central authority in the background, Mobile ad hoc networks are always vulnerable to some security issues and performance issues. The security imposes a huge impact on the performance of any network. Some of the security issues are black hole attack, flooding, wormhole attack etc. In this paper, we will discuss issues regarding low performance of Watchdog protocol used in the MANET and proposed an improved Watchdog mechanism, which is called by I-Watchdog protocol that overcomes the limitations of Watchdog protocol and gives high performance in terms of throughput, delay.

A fault-tolerant small world topology control model in ad hoc networks for search and rescue

Science.gov (United States)

Tan, Mian; Fang, Ling; Wu, Yue; Zhang, Bo; Chang, Bowen; Holme, Petter; Zhao, Jing

2018-02-01

Due to their self-organized, multi-hop and distributed characteristics, ad hoc networks are useful in search and rescue. Topology control models need to be designed for energy-efficient, robust and fast communication in ad hoc networks. This paper proposes a topology control model which specializes for search and rescue-Compensation Small World-Repeated Game (CSWRG)-which integrates mobility models, constructing small world networks and a game-theoretic approach to the allocation of resources. Simulation results show that our mobility models can enhance the communication performance of the constructed small-world networks. Our strategy, based on repeated game, can suppress selfish behavior and compensate agents that encounter selfish or faulty neighbors. This model could be useful for the design of ad hoc communication networks.

Report of the evaluation by the Ad Hoc Review Committee on Health Physics. Result evaluation in fiscal year 2000

International Nuclear Information System (INIS)

2001-06-01

The Research Evaluation Committee, which consisted of 14 members from outside of the Japan Atomic Energy Research Institute (JAERI), set up an Ad Hoc Review Committee on Health Physics in accordance with the 'Fundamental Guideline for the Evaluation of Research and Development (R and D) at JAERI' and its subsidiary regulations in order to evaluate the R and D accomplishments achieved for five years from Fiscal Year 1995 to Fiscal Year 1999 at Department of Health Physics in Tokai Research Establishment and at related departments in other Establishments of JAERI. The Ad Hoc Review Committee consisted of six specialists from outside of JAERI. The Ad Hoc Review Committee conducted its activities from October 2000 to January 2001. The evaluation was performed on the basis of the materials submitted in advance and of the oral presentations made at the Ad Hoc Review Committee meeting which was held on October 10, 2000, in line with the items, viewpoints, and criteria for the evaluation specified by the Research Evaluation Committee. The result of the evaluation by the Ad Hoc Review Committee was submitted to the Research Evaluation Committee, and was judged to be appropriate at its meeting held on March 16, 2001. This report describes the result of the evaluation by the Ad Hoc Review Committee on Health Physics. (author)

Ad Hoc Transient Groups: Instruments for Awareness in Learning Networks

NARCIS (Netherlands)

Fetter, Sibren; Rajagopal, Kamakshi; Berlanga, Adriana; Sloep, Peter

2011-01-01

Fetter, S., Rajagopal, K., Berlanga, A. J., & Sloep, P. B. (2011). Ad Hoc Transient Groups: Instruments for Awareness in Learning Networks. In W. Reinhardt, T. D. Ullmann, P. Scott, V. Pammer, O. Conlan, & A. J. Berlanga (Eds.), Proceedings of the 1st European Workshop on Awareness and Reflection in

Maximization of Energy Efficiency in Wireless ad hoc and Sensor Networks With SERENA

Directory of Open Access Journals (Sweden)

Saoucene Mahfoudh

2009-01-01

Full Text Available In wireless ad hoc and sensor networks, an analysis of the node energy consumption distribution shows that the largest part is due to the time spent in the idle state. This result is at the origin of SERENA, an algorithm to SchEdule RoutEr Nodes Activity. SERENA allows router nodes to sleep, while ensuring end-to-end communication in the wireless network. It is a localized and decentralized algorithm assigning time slots to nodes. Any node stays awake only during its slot and the slots assigned to its neighbors, it sleeps the remaining time. Simulation results show that SERENA enables us to maximize network lifetime while increasing the number of user messages delivered. SERENA is based on a two-hop coloring algorithm, whose complexity in terms of colors and rounds is evaluated. We then quantify the slot reuse. Finally, we show how SERENA improves the node energy consumption distribution and maximizes the energy efficiency of wireless ad hoc and sensor networks. We compare SERENA with classical TDMA and optimized variants such as USAP in wireless ad hoc and sensor networks.

Signaling-Free Max-Min Airtime Fairness in IEEE 802.11 Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Youngsoo Lee

2016-01-01

Full Text Available We propose a novel media access control (MAC protocol, referred to as signaling-free max-min airtime fair (SMAF MAC, to improve fairness and channel utilization in ad hoc networks based on IEEE 802.11 wireless local area networks (WLANs. We introduce busy time ratio (BTR as a measure for max-min airtime fairness. Each node estimates its BTR and adjusts the transmission duration by means of frame aggregation and fragmentation, so that it can implicitly announce the BTR to neighbor nodes. Based on the announced BTR, each of the neighbor nodes controls its contention window. In this way, the SMAF MAC works in a distributed manner without the need to know the max-min fair share of airtime, and it does not require exchanging explicit control messages among nodes to attain fairness. Moreover, we successfully incorporate the hidden node detection and resolution mechanisms into the SMAF MAC to deal with the hidden node problem in ad hoc networks. The simulation results confirm that the SMAF MAC enhances airtime fairness without degrading channel utilization, and it effectively resolves several serious problems in ad hoc networks such as the starvation, performance anomaly, and hidden node problems.

Power control algorithms for mobile ad hoc networks

Directory of Open Access Journals (Sweden)

Nuraj L. Pradhan

2011-07-01

We will also focus on an adaptive distributed power management (DISPOW algorithm as an example of the multi-parameter optimization approach which manages the transmit power of nodes in a wireless ad hoc network to preserve network connectivity and cooperatively reduce interference. We will show that the algorithm in a distributed manner builds a unique stable network topology tailored to its surrounding node density and propagation environment over random topologies in a dynamic mobile wireless channel.

Multicasting in Wireless Communications (Ad-Hoc Networks): Comparison against a Tree-Based Approach

Science.gov (United States)

Rizos, G. E.; Vasiliadis, D. C.

2007-12-01

We examine on-demand multicasting in ad hoc networks. The Core Assisted Mesh Protocol (CAMP) is a well-known protocol for multicast routing in ad-hoc networks, generalizing the notion of core-based trees employed for internet multicasting into multicast meshes that have much richer connectivity than trees. On the other hand, wireless tree-based multicast routing protocols use much simpler structures for determining route paths, using only parent-child relationships. In this work, we compare the performance of the CAMP protocol against the performance of wireless tree-based multicast routing protocols, in terms of two important factors, namely packet delay and ratio of dropped packets.

A Spontaneous Ad Hoc Network to Share WWW Access

Directory of Open Access Journals (Sweden)

Lloret Jaime

2010-01-01

Full Text Available In this paper, we propose a secure spontaneous ad-hoc network, based on direct peer-to-peer interaction, to grant a quick, easy, and secure access to the users to surf the Web. The paper shows the description of our proposal, the procedure of the nodes involved in the system, the security algorithms implemented, and the designed messages. We have taken into account the security and its performance. Although some people have defined and described the main features of spontaneous ad-hoc networks, nobody has published any design and simulation until today. Spontaneous networking will enable a more natural form of wireless computing when people physically meet in the real world. We also validate the success of our proposal through several simulations and comparisons with a regular architecture, taking into account the optimization of the resources of the devices. Finally, we compare our proposal with other caching techniques published in the related literature. The proposal has been developed with the main objective of improving the communication and integration between different study centers of low-resource communities. That is, it lets communicate spontaneous networks, which are working collaboratively and which have been created on different physical places.

Energy Efficient Probabilistic Broadcasting for Mobile Ad-Hoc Network

Science.gov (United States)

Kumar, Sumit; Mehfuz, Shabana

2017-06-01

In mobile ad-hoc network (MANETs) flooding method is used for broadcasting route request (RREQ) packet from one node to another node for route discovery. This is the simplest method of broadcasting of RREQ packets but it often results in broadcast storm problem, originating collisions and congestion of packets in the network. A probabilistic broadcasting is one of the widely used broadcasting scheme for route discovery in MANETs and provides solution for broadcasting storm problem. But it does not consider limited energy of the battery of the nodes. In this paper, a new energy efficient probabilistic broadcasting (EEPB) is proposed in which probability of broadcasting RREQs is calculated with respect to remaining energy of nodes. The analysis of simulation results clearly indicate that an EEPB route discovery scheme in ad-hoc on demand distance vector (AODV) can increase the network lifetime with a decrease in the average power consumption and RREQ packet overhead. It also decreases the number of dropped packets in the network, in comparison to other EEPB schemes like energy constraint gossip (ECG), energy aware gossip (EAG), energy based gossip (EBG) and network lifetime through energy efficient broadcast gossip (NEBG).

Ad hoc Sensor Networks to Support Maritime Interdiction Operations

OpenAIRE

Osmundson, John; Bordetsky, Alex

2014-01-01

Networking sensors, decision centers, and boarding parties supports success in Maritime Interdiction Operations. Led by a team from Naval Post-graduate School (NPS), experiments were conducted in 2012 to test the use of ad-hoc, self-forming communication networks to link sensors, people, and decision centers. The experiments involved international participants and successfully shared valuable biometric and radiological sensor data between boarding parties and decis...

Peer-to-peer over mobile ad hoc networks (Chapter 11)

NARCIS (Netherlands)

Qadri, N.N.; Liotta, A.; Pierre, S.

2010-01-01

In this chapter we review various approaches for the convergence of Peer-to-Peer (P2P) and Mobile Ad hoc Networks (MANETs), identifying strengths and weaknesses, and putting things in perspective. P2P and MANETs are among the most active research topics in pervasive computing. The convergence of P2P

Intelligent Stale-Frame Discards for Real-Time Video Streaming over Wireless Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Sheu Tsang-Ling

2009-01-01

Full Text Available Abstract This paper presents intelligent early packet discards (I-EPD for real-time video streaming over a multihop wireless ad hoc network. In a multihop wireless ad hoc network, the quality of transferring real-time video streams could be seriously degraded, since every intermediate node (IN functionally like relay device does not possess large buffer and sufficient bandwidth. Even worse, a selected relay node could leave or power off unexpectedly, which breaks the route to destination. Thus, a stale video frame is useless even if it can reach destination after network traffic becomes smooth or failed route is reconfigured. In the proposed I-EPD, an IN can intelligently determine whether a buffered video packet should be early discarded. For the purpose of validation, we implement the I-EPD on Linux-based embedded systems. Via the comparisons of performance metrics (packet/frame discards ratios, PSNR, etc., we demonstrate that video quality over a wireless ad hoc network can be substantially improved and unnecessary bandwidth wastage is greatly reduced.

Cross-Layer Service Discovery Mechanism for OLSRv2 Mobile Ad Hoc Networks

Directory of Open Access Journals (Sweden)

M. Isabel Vara

2015-07-01

Full Text Available Service discovery plays an important role in mobile ad hoc networks (MANETs. The lack of central infrastructure, limited resources and high mobility make service discovery a challenging issue for this kind of network. This article proposes a new service discovery mechanism for discovering and advertising services integrated into the Optimized Link State Routing Protocol Version 2 (OLSRv2. In previous studies, we demonstrated the validity of a similar service discovery mechanism integrated into the previous version of OLSR (OLSRv1. In order to advertise services, we have added a new type-length-value structure (TLV to the OLSRv2 protocol, called service discovery message (SDM, according to the Generalized MANET Packet/Message Format defined in Request For Comments (RFC 5444. Each node in the ad hoc network only advertises its own services. The advertisement frequency is a user-configurable parameter, so that it can be modified depending on the user requirements. Each node maintains two service tables, one to store information about its own services and another one to store information about the services it discovers in the network. We present simulation results, that compare our service discovery integrated into OLSRv2 with the one defined for OLSRv1 and with the integration of service discovery in Ad hoc On-demand Distance Vector (AODV protocol, in terms of service discovery ratio, service latency and network overhead.

Cross-Layer Service Discovery Mechanism for OLSRv2 Mobile Ad Hoc Networks.

Science.gov (United States)

Vara, M Isabel; Campo, Celeste

2015-07-20

Service discovery plays an important role in mobile ad hoc networks (MANETs). The lack of central infrastructure, limited resources and high mobility make service discovery a challenging issue for this kind of network. This article proposes a new service discovery mechanism for discovering and advertising services integrated into the Optimized Link State Routing Protocol Version 2 (OLSRv2). In previous studies, we demonstrated the validity of a similar service discovery mechanism integrated into the previous version of OLSR (OLSRv1). In order to advertise services, we have added a new type-length-value structure (TLV) to the OLSRv2 protocol, called service discovery message (SDM), according to the Generalized MANET Packet/Message Format defined in Request For Comments (RFC) 5444. Each node in the ad hoc network only advertises its own services. The advertisement frequency is a user-configurable parameter, so that it can be modified depending on the user requirements. Each node maintains two service tables, one to store information about its own services and another one to store information about the services it discovers in the network. We present simulation results, that compare our service discovery integrated into OLSRv2 with the one defined for OLSRv1 and with the integration of service discovery in Ad hoc On-demand Distance Vector (AODV) protocol, in terms of service discovery ratio, service latency and network overhead.

The accuracy of interpreting key psychiatric terms by ad hoc ...

African Journals Online (AJOL)

MacFarlane et al.15 note that a greater number of people have a preference for working with ad hoc interpreters in comparison to professional interpreters ... As part of a larger study, a cross-sectional qualitative interview design was used to ..... obstacle they would face if they would receive training. They had concerns over ...

Taxonomic and ad hoc categorization within the two cerebral hemispheres.

Science.gov (United States)

Shen, Yeshayahu; Aharoni, Bat-El; Mashal, Nira

2015-01-01

A typicality effect refers to categorization which is performed more quickly or more accurately for typical than for atypical members of a given category. Previous studies reported a typicality effect for category members presented in the left visual field/right hemisphere (RH), suggesting that the RH applies a similarity-based categorization strategy. However, findings regarding the typicality effect within the left hemisphere (LH) are less conclusive. The current study tested the pattern of typicality effects within each hemisphere for both taxonomic and ad hoc categories, using words presented to the left or right visual fields. Experiment 1 tested typical and atypical members of taxonomic categories as well as non-members, and Experiment 2 tested typical and atypical members of ad hoc categories as well as non-members. The results revealed a typicality effect in both hemispheres and in both types of categories. Furthermore, the RH categorized atypical stimuli more accurately than did the LH. Our findings suggest that both hemispheres rely on a similarity-based categorization strategy, but the coarse semantic coding of the RH seems to facilitate the categorization of atypical members.

Autonomous Power Control MAC Protocol for Mobile Ad Hoc Networks

Directory of Open Access Journals (Sweden)

2006-01-01

Full Text Available Battery energy limitation has become a performance bottleneck for mobile ad hoc networks. IEEE 802.11 has been adopted as the current standard MAC protocol for ad hoc networks. However, it was developed without considering energy efficiency. To solve this problem, many modifications on IEEE 802.11 to incorporate power control have been proposed in the literature. The main idea of these power control schemes is to use a maximum possible power level for transmitting RTS/CTS and the lowest acceptable power for sending DATA/ACK. However, these schemes may degrade network throughput and reduce the overall energy efficiency of the network. This paper proposes autonomous power control MAC protocol (APCMP, which allows mobile nodes dynamically adjusting power level for transmitting DATA/ACK according to the distances between the transmitter and its neighbors. In addition, the power level for transmitting RTS/CTS is also adjustable according to the power level for DATA/ACK packets. In this paper, the performance of APCMP protocol is evaluated by simulation and is compared with that of other protocols.

Report of the evaluation by the Ad Hoc Review Committee on Information Technology. In-advance evaluation in fiscal year 2000

International Nuclear Information System (INIS)

2001-06-01

The Research Evaluation Committee, which consisted of 14 members from outside of the Japan Atomic Energy Research Institute (JAERI), set up an Ad Hoc Review Committee on Information Technology in accordance with the Fundamental Guideline for the Evaluation of Research and Development (R and D) at JAERI' and its subsidiary regulations in order to evaluate the adequacy of the R and D programs pertaining to the establishment and utilization of the Information Technology Based Laboratory (ITBL) to be implemented for five years starting in Fiscal Year 2001 at Center for Promotion of Computational Science and Engineering and Department of Environmental Sciences of JAERI. The Ad Hoc Review Committee consisted of eight specialists from outside of JAERI. The Ad Hoc Review Committee conducted its activities from February to March 2001. The evaluation was performed on the basis of the materials submitted in advance and of the oral presentations made at the Ad Hoc Review Committee meeting which was held on February 9, 2001, in line with the items, viewpoints, and criteria for the evaluation specified by the Research Evaluation Committee. The result of the evaluation by the Ad Hoc Review Committee was submitted to the Research Evaluation Committee, and was judged to be appropriate at its meeting held on March 16, 2001. This report describes the result of the evaluation by the Ad Hoc Review Committee on Information Technology. (author)

Performance Analysis of Hierarchical Group Key Management Integrated with Adaptive Intrusion Detection in Mobile ad hoc Networks

Science.gov (United States)

2016-04-05

applications in wireless networks such as military battlefields, emergency response, mobile commerce , online gaming, and collaborative work are based on the...www.elsevier.com/locate/peva Performance analysis of hierarchical group key management integrated with adaptive intrusion detection in mobile ad hoc...Accepted 19 September 2010 Available online 26 September 2010 Keywords: Mobile ad hoc networks Intrusion detection Group communication systems Group

Cross-Layer Design Approach for Power Control in Mobile Ad Hoc Networks

Directory of Open Access Journals (Sweden)

A. Sarfaraz Ahmed

2015-03-01

Full Text Available In mobile ad hoc networks, communication among mobile nodes occurs through wireless medium The design of ad hoc network protocol, generally based on a traditional “layered approach”, has been found ineffective to deal with receiving signal strength (RSS-related problems, affecting the physical layer, the network layer and transport layer. This paper proposes a design approach, deviating from the traditional network design, toward enhancing the cross-layer interaction among different layers, namely physical, MAC and network. The Cross-Layer design approach for Power control (CLPC would help to enhance the transmission power by averaging the RSS values and to find an effective route between the source and the destination. This cross-layer design approach was tested by simulation (NS2 simulator and its performance over AODV was found to be better.

Correctness-by-construction and post-hoc verification : a marriage of convenience?

NARCIS (Netherlands)

Watson, B.W.; Kourie, D.G.; Schaefer, I.; Cleophas, L.G.W.A.; Margaria, T.; Steffen, B.

2016-01-01

Correctness-by-construction (CbC), traditionally based on weakest precondition semantics, and post-hoc verification (PhV) aspire to ensure functional correctness. We argue for a lightweight approach to CbC where lack of formal rigour increases productivity. In order to mitigate the risk of

Illustration, detection and prevention of sleep deprivation anomaly in mobile ad hoc networks

International Nuclear Information System (INIS)

Nadeem, A.; Ahsan, K.; Sarim, M.

2017-01-01

MANETs (Mobile Ad Hoc Networks) have applications in various walks of life from rescue operations to battle field operations, personal and commercial. However, routing operations in MANETs are still vulnerable to anomalies and DoS (Denial of Service) attacks such as sleep deprivation. In SD (Sleep Deprivation) attack malicious node exploits the vulnerability in the route discovery function of the reactive routing protocol for example AODV (Ad Hoc On-Demand Distance Vector). In this paper, we first illustrate the SD anomaly in MANETs and then propose a SD detection and prevention algorithm which efficiently deals with this attack. We assess the performance of our proposed approach through simulation, evaluating its successfulness using different network scenarios. (author)

Position-Based Packet Forwarding for Vehicular Ad-Hoc Networks

OpenAIRE

Füßler, Holger

2007-01-01

Mobile Ad-Hoc Networks, or MANETs, are data communication networks between (potentially) mobile computer systems equipped with wireless communication devices and — in their purest form — in complete absence of communication infrastructure. Usage scenarios for these systems include communication during disaster recovery or battlefield communications. One of the great research challenges concerning MANETs is the Packet Forwarding Problem, i.e., the question to which neighbor node a data packet ...

Protocols for Detection and Removal of Wormholes for Secure Routing and Neighborhood Creation in Wireless Ad Hoc Networks

Science.gov (United States)

Hayajneh, Thaier Saleh

2009-01-01

Wireless ad hoc networks are suitable and sometimes the only solution for several applications. Many applications, particularly those in military and critical civilian domains (such as battlefield surveillance and emergency rescue) require that ad hoc networks be secure and stable. In fact, security is one of the main barriers to the extensive use…

Report of the evaluation by the Ad Hoc Review Committee on Materials Science Research. Ex-post evaluation in fiscal year 2003

International Nuclear Information System (INIS)

2004-06-01

The Research Evaluation Committee, which consisted of 13 members from outside of the Japan Atomic Energy Research Institute (JAERI), set up an Ad Hoc Review Committee on Materials Science Research in accordance with the Fundamental Guideline for the Evaluation of Research and Development (R and D) at JAERI' and its subsidiary regulations in order to evaluate the adequacy of the R and D results achieved for five years until Fiscal Year 2002 at Department of Materials Science in Tokai Research Establishment of JAERI. The Ad Hoc Review Committee consisted of eight specialists from outside of JAERI. The Ad Hoc Review Committee conducted its activities from October 2003 to February 2004. The evaluation was performed on the basis of the materials submitted in advance and of the oral presentations made at the Ad Hoc Review Committee meeting which was held on November 14, 2003, in line with the items, viewpoints, and criteria for the evaluation specified by the Research Evaluation Committee. The result of the evaluation by the Ad Hoc Review Committee was submitted to the Research Evaluation Committee, and was judged to be appropriate at its meeting held on March 8, 2004. This report describes the result of the evaluation by the Ad Hoc Review Committee on Materials Science Research. (author)

Report of the evaluation by the Ad Hoc Review Committee on Computational Science and Engineering. Result evaluation in fiscal year 2000

International Nuclear Information System (INIS)

2001-06-01

The Research Evaluation Committee, which consisted of 14 members from outside of the Japan Atomic Energy Research Institute (JAERI), set up an Ad Hoc Review Committee on Computational Science and Engineering in accordance with the 'Fundamental Guideline for the Evaluation of Research and Development (R and D) at JAERI' and its subsidiary regulations in order to evaluate the R and D accomplishments achieved for five years from Fiscal Year 1995 to Fiscal Year 1999 at Center for Promotion of Computational Science and Engineering of JAERI. The Ad Hoc Review Committee consisted of seven specialists from outside of JAERI. The Ad Hoc Review Committee conducted its activities from December 2000 to March 2001. The evaluation was performed on the basis of the materials submitted in advance and of the oral presentations made at the Ad Hoc Review Committee meeting which was held on December 27, 2000, in line with the items, viewpoints, and criteria for the evaluation specified by the Research Evaluation Committee. The result of the evaluation by the Ad Hoc Review Committee was submitted to the Research Evaluation Committee, and was judged to be appropriate at its meeting held on March 16, 2001. This report describes the result of the evaluation by the Ad Hoc Review Committee on Computational Science and Engineering. (author)

An Ad-Hoc Opportunistic Dissemination Protocol for Smartphone-based Participatory Traffic Monitoring

NARCIS (Netherlands)

Türkes, Okan; Seraj, Fatjon; Scholten, Johan; Meratnia, Nirvana; Havinga, Paul J.M.

2015-01-01

This study introduces an ad-hoc opportunistic data dissemination protocol, called VADISS, that facilitates participatory traffic monitoring applications with smartphones. As a ubiquitous alternative to existing vehicular networking methods, VADISS uses the default WiFi interfaces universally adopted

Conflict Management in "Ad Hoc" Problem-Solving Groups: A Preliminary Investigation.

Science.gov (United States)

Wallace, Les; Baxter, Leslie

Full study of small group communication must include consideration of task and socio-emotional dimensions, especially in relation to group problem solving. Thirty small groups were tested for their reactions in various "ad hoc" conflict resolution situations. Instructions to the groups were (1) no problem-solving instructions (control),…

A multi-protocol framework for ad-hoc service discovery

OpenAIRE

Flores-Cortes, C.; Blair, Gordon S.; Grace, P.

2006-01-01

Discovering the appropriate services in ad-hoc computing environments where a great number of devices and software components collaborate discreetly and provide numerous services is an important challenge. Service discovery protocols make it possible for participating nodes in a network to locate and advertise services with minimum user intervention. However, because it is not possible to predict at design time which protocols will be used to advertise services in a given context/environment,...

Brazilian Multinationals ́ Competences: Impacts of a “Tug of War” Between Cultural Legacies and Global Mindedness

Directory of Open Access Journals (Sweden)

Germano Glufke Reis

2015-01-01

Full Text Available This study investigates the simultaneous influences of culture and global mindedness on the foreign subsidiaries of Brazilian multinationals (B rMNs. Because the ability to develop competences abroad is critical for emerging multina tionals competitiveness, we proposed hypotheses and tested a model for how the competenc es of subsidiaries may be affected by the dimensions of global mindedness and culture. To do so, we conducted a multilevel survey involving the headquarters and subsidiaries of majo r BrMNs. The results suggest that global mindedness, which encompasses global orientation, g lobal knowledge, and global skills, is positively related to the development of subsidiari es ́ competences. By contrast, cultural factors, including power distance and uncertainty a voidance, are negatively related to competences development. Therefore, these dimension s may exert simultaneous and opposing stimuli and unaligned forces that affect the develo pment of competences abroad, generating a “tug of war” effect.

A LOOP-BASED APPROACH IN CLUSTERING AND ROUTING IN MOBILE AD HOC NETWORKS

Institute of Scientific and Technical Information of China (English)

Li Yanping; Wang Xin; Xue Xiangyang; C.K. Toh

2006-01-01

Although clustering is a convenient framework to enable traffic control and service support in Mobile Ad hoc NETworks (MANETs), it is seldom adopted in practice due to the additional traffic overhead it leads to for the resource limited ad hoc network. In order to address this problem, we proposed a loop-based approach to combine clustering and routing. By employing loop topologies, topology information is disseminated with a loop instead of a single node, which provides better robustness, and the nature of a loop that there are two paths between each pair of nodes within a loop suggests smart route recovery strategy. Our approach is composed of setup procedure, regular procedure and recovery procedure to achieve clustering, routing and emergent route recovering.

Mobile ad hoc networking the cutting edge directions

CERN Document Server

Basagni, Stefano; Giordano, Silvia; Stojmenovic, Ivan

2013-01-01

""An excellent book for those who are interested in learning the current status of research and development . . . [and] who want to get a comprehensive overview of the current state-of-the-art.""-E-Streams This book provides up-to-date information on research and development in the rapidly growing area of networks based on the multihop ad hoc networking paradigm. It reviews all classes of networks that have successfully adopted this paradigm, pointing out how they penetrated the mass market and sparked breakthrough research. Covering both physical issues and applica

A Cross Layer Solution to Address TCP Intra-flow Performance Degradation in Multihop Ad hoc Networks

OpenAIRE

Rakocevic, V.; Hamadani, E.

2008-01-01

Incorporating the concept of TCP end-to-end congestion control for wireless networks is one of the primary concerns in designing ad hoc networks since TCP was primarily designed and optimized based on the assumptions for wired networks. In this study, our interest lies on tackling the TCP instability and in particular intra-flow instability problem since due to the nature of applications in multihop ad hoc networks, connection instability or starvation even for a short period of time can have...

Adaptive Demand-Driven Multicast Routing in Multi-Hop Wireless Ad Hoc Networks

National Research Council Canada - National Science Library

Jetcheva, Jorjeta G

2004-01-01

...) nodes that wish to communicate. Each node in the ad hoc network acts as a router and forwards packets on behalf of other nodes, allowing nodes that are not within wireless range of each other to communicate over multi-hop paths...

Report of the evaluation by the Ad Hoc Review Committee on Materials Science Research. In-advance evaluation in fiscal year 2002

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-11-01

The Research Evaluation Committee, which consisted of 13 members from outside of the Japan Atomic Energy Research Institute (JAERI), set up an Ad Hoc Review Committee on Materials Science Research in accordance with the Fundamental Guideline for the Evaluation of Research and Development (R and D) at JAERI' and its subsidiary regulations in order to evaluate the adequacy of the R and D programs to be implemented for five years starting in Fiscal Year 2003 at Department of Materials Science in Tokai Research Establishment of JAERI. The Ad Hoc Review Committee consisted of eight specialists from outside of JAERI. The Ad Hoc Review Committee conducted its activities from April 2002 to August 2002. The evaluation was performed on the basis of the materials submitted in advance and of the oral presentations made at the Ad Hoc Review Committee meeting which was held on June 5th, 2002, in line with the items, viewpoints, and criteria for the evaluation specified by the Research Evaluation Committee. The result of the evaluation by the Ad Hoc Review Committee was submitted to the Research Evaluation Committee, and was judged to be appropriate at its meeting held on August 5th, 2002. This report describes the result of the evaluation by the Ad Hoc Review Committee on Materials Science Research. (author)

Report of the evaluation by the Ad Hoc Review Committee on Materials Science Research. In-advance evaluation in fiscal year 2002

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-11-01

The Research Evaluation Committee, which consisted of 13 members from outside of the Japan Atomic Energy Research Institute (JAERI), set up an Ad Hoc Review Committee on Materials Science Research in accordance with the Fundamental Guideline for the Evaluation of Research and Development (R and D) at JAERI' and its subsidiary regulations in order to evaluate the adequacy of the R and D programs to be implemented for five years starting in Fiscal Year 2003 at Department of Materials Science in Tokai Research Establishment of JAERI. The Ad Hoc Review Committee consisted of eight specialists from outside of JAERI. The Ad Hoc Review Committee conducted its activities from April 2002 to August 2002. The evaluation was performed on the basis of the materials submitted in advance and of the oral presentations made at the Ad Hoc Review Committee meeting which was held on June 5th, 2002, in line with the items, viewpoints, and criteria for the evaluation specified by the Research Evaluation Committee. The result of the evaluation by the Ad Hoc Review Committee was submitted to the Research Evaluation Committee, and was judged to be appropriate at its meeting held on August 5th, 2002. This report describes the result of the evaluation by the Ad Hoc Review Committee on Materials Science Research. (author)

Report of the evaluation by the ad hoc review committee on radiation application research. In-advance evaluation in fiscal year 2001

International Nuclear Information System (INIS)

2001-11-01

The Research Evaluation Committee, which consisted of 13 members from outside of the Japan Atomic Energy Research Institute (JAERI), set up an Ad Hoc Review Committee on Radiation Application Research in accordance with the Fundamental Guideline for the Evaluation of Research and Development (R and D) at JAERI' and its subsidiary regulations in order to evaluate the adequacy of the R and D programs to be implemented for five years starting in Fiscal Year 2002 at Department of Material Development, at Department of Ion-Beam-Applied Biology and at Advanced Radiation Technology Center in Takasaki Radiation Chemistry Research Establishment of JAERI. The Ad Hoc Review Committee consisted of ten specialists from outside of JAERI. The Ad Hoc Review Committee conducted its activities from May to July 2001. The evaluation was performed on the basis of the materials submitted in advance and of the oral presentations made at the Ad Hoc Review Committee meeting which was held on June 25, 2001, in line with the items, viewpoints, and criteria for the evaluation specified by the Research Evaluation Committee. The result of the evaluation by the Ad Hoc Review Committee was submitted to the Research Evaluation Committee, and was judged to be appropriate at its meeting held on July 12, 2001. This report describes the result of the evaluation by the Ad Hoc Review Committee on Radiation Application Research. (author)

Sistem Verifikasi Tanda Tangan Off-Line Berdasar Ciri Histogram Of Oriented Gradient (HOG Dan Histogram Of Curvature (HoC

Directory of Open Access Journals (Sweden)

Agus Wahyu Widodo

2015-08-01

Full Text Available Abstrak Tanda tangan dengan sifat uniknya merupakan salah satu dari sekian banyak atribut personal yang diterima secara luas untuk verifikasi indentitas seseorang, alat pembuktian kepemilikan berbagai transaksi atau dokumen di dalam masyarakat. Keberhasilan penggunaan ciri gradien dan curvature dalam bidang-bidang penelitian pengenalan pola dan bahwa tanda tangan dapat dikatakan merupakan hasil tulisan tangan yang tersusun atas beragam garis dan lengkungan (curve yang memiliki arah atau orientasi merupakan alasan bahwa kedua ciri tersebut digunakan sebagai metoda verifikasi tanda tangan offline di penelitian ini. Berbagai implementasi dari pre-processing, ekstraksi dan representasi ciri, dan pembelajaran SVM serta usaha perbaikan yang telah dilakukan dalam penelitian ini menunjukkan hasil bahwa ciri HOG dan HoC mampu dimanfaatkan dalam proses verifikasi tanda tangan secara offline.  Pada basis data GPDS960Signature, HOG dan HoC yang dihitung pada ukuran sel 30 x 30 piksel memberikan dengan nilai %FRR terbaik 26,90 dan %FAR 37,56.  Sedangkan pada basis data FUM-PHSDB, HOG dn HoC yang dihitung pada ukuran 60 x 60 piksel memberikan nilai %FRR terbaik 4 dan %FAR 57. Kata kunci: verifikasi tanda tangan, curvature, orientation, gradient, histogram of curvature (HoC, histogram of oriented gradient (HOG Abstract Signature with unique properties is one of the many personal attributes that are widely accepted to verify a person's identity, proof of ownership transactions instrument or document in the community. The successful use of gradient and curvature feature in the research fields of pattern recognition is the reason that both of these features are used as an offline signature verification method in this study. Various implementations of preprocessing, feature extraction and representation, and SVM learning has been done in the study showed results that HOG and HoC feature can be utilized in the process of offline signature verification.  HOG and

Ad-hoc Content-based Queries and Data Analysis for Virtual Observatories, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Aquilent, Inc. proposes to support ad-hoc, content-based query and data retrieval from virtual observatories (VxO) by developing 1) Higher Order Query Services that...

Interference in wireless ad hoc networks with smart antennas

KAUST Repository

Alabdulmohsin, Ibrahim

2014-08-01

In this paper, we show that the use of directional antennas in wireless ad hoc networks can actually increase interference due to limitations of virtual carrier sensing. We derive a simple mathematical expression for interference in both physical and virtual carrier sense networks, which reveals counter-intuitively that receivers in large dense networks with directional antennas can experience larger interference than in omnidirectional networks unless the beamwidth is sufficiently small. Validity of mathematical analysis is confirmed using simulations.

Formal reconstruction of attack scenarios in mobile ad hoc and sensor networks

Directory of Open Access Journals (Sweden)

Rekhis Slim

2011-01-01

Full Text Available Abstract Several techniques of theoretical digital investigation are presented in the literature but most of them are unsuitable to cope with attacks in wireless networks, especially in Mobile Ad hoc and Sensor Networks (MASNets. In this article, we propose a formal approach for digital investigation of security attacks in wireless networks. We provide a model for describing attack scenarios in a wireless environment, and system and network evidence generated consequently. The use of formal approaches is motivated by the need to avoid ad hoc generation of results that impedes the accuracy of analysis and integrity of investigation. We develop an inference system that integrates the two types of evidence, handles incompleteness and duplication of information in them, and allows possible and provable actions and attack scenarios to be generated. To illustrate the proposal, we consider a case study dealing with the investigation of a remote buffer overflow attack.

Safety regulations for radioisotopes, etc. (interim report)

International Nuclear Information System (INIS)

1980-01-01

An (interim) report by an ad hoc expert committee to the Nuclear Safety Commission, on the safety regulations for radioisotopes, etc., was presented. For the utilization of radioisotopes, etc., there is the Law Concerning Prevention of Radiation Injury Due to Radioisotopes, etc. with the advances in this field and the improvement in international standards, the regulations by the law have been examined. After explaining the basic ideas of the regulations, the problems and countermeasures in the current regulations are described: legal system, rationalization in permission procedures and others, inspection on RI management, the system of the persons in charge of radiation handling, RI transport, low-level radioactive wastes, consumer goods, definitions of RIs, radiation and sealed sources, regulations by group partitioning, RI facilities, system of personnel exposure registration, entrusting of inspection, etc. to private firms, and reduction in the works for permission among governmental offices. (author)

Enhancing On-Demand Multicast Routing Protocols using Mobility Prediction in Mobile Ad-hoc Network

Directory of Open Access Journals (Sweden)

Nermin Makhlouf

2014-08-01

Full Text Available A Mobile Ad hoc Network (MANET is a self-organizing wireless communication network in which mobile devices are based on no infrastructure like base stations or access points. Minimal configuration and quick deployment make ad hoc networks suitable for emergency situations like disaster recovery or military conflict. Since node mobility may cause links to be broken frequently, a very important issue for routing in MANETs is how to set reliable paths which can last as long as possible. To solve this problem, non-random behaviors for the mobility patterns that mobile users exhibit are exploited. This paper introduces a scheme to improve On-Demand Multicast Routing Protocol (ODMRP performances by using mobility prediction. 

Design of free patterns of nanocrystals with ad hoc features via templated dewetting

Energy Technology Data Exchange (ETDEWEB)

Aouassa, M.; Berbezier, I.; Favre, L.; Ronda, A. [IM2NP, CNRS, AMU, Marseille (France); Bollani, M.; Sordan, R. [LNES, Como (Italy); Delobbe, A.; Sudraud, P. [Orsay Physics, Fuveau (France)

2012-07-02

Design of monodisperse ultra-small nanocrystals (NCs) into large scale patterns with ad hoc features is demonstrated. The process makes use of solid state dewetting of a thin film templated through alloy liquid metal ion source focused ion beam (LMIS-FIB) nanopatterning. The solid state dewetting initiated at the edges of the patterns controllably creates the ordering of NCs with ad hoc placement and periodicity. The NC size is tuned by varying the nominal thickness of the film while their position results from the association of film retraction from the edges of the lay out and Rayleigh-like instability. The use of ultra-high resolution LMIS-FIB enables to produce monocrystalline NCs with size, periodicity, and placement tunable as well. It provides routes for the free design of nanostructures for generic applications in nanoelectronics.

The impact of brief team communication, leadership and team behavior training on ad hoc team performance in trauma care settings.

Science.gov (United States)

Roberts, Nicole K; Williams, Reed G; Schwind, Cathy J; Sutyak, John A; McDowell, Christopher; Griffen, David; Wall, Jarrod; Sanfey, Hilary; Chestnut, Audra; Meier, Andreas H; Wohltmann, Christopher; Clark, Ted R; Wetter, Nathan

2014-02-01

Communication breakdowns and care coordination problems often cause preventable adverse patient care events, which can be especially acute in the trauma setting, in which ad hoc teams have little time for advanced planning. Existing teamwork curricula do not address the particular issues associated with ad hoc emergency teams providing trauma care. Ad hoc trauma teams completed a preinstruction simulated trauma encounter and were provided with instruction on appropriate team behaviors and team communication. Teams completed a postinstruction simulated trauma encounter immediately afterward and 3 weeks later, then completed a questionnaire. Blinded raters rated videotapes of the simulations. Participants expressed high levels of satisfaction and intent to change practice after the intervention. Participants changed teamwork and communication behavior on the posttest, and changes were sustained after a 3-week interval, though there was some loss of retention. Brief training exercises can change teamwork and communication behaviors on ad hoc trauma teams. Copyright © 2014 Elsevier Inc. All rights reserved.

Report of the Ad Hoc Committee on SSC physics

International Nuclear Information System (INIS)

1990-04-01

The Ad Hoc Committee on SSC Physics has reexamined the relationship between beam energy, machine luminosity, and physics capability. In the next section, the physics motivation for the SSC is reviewed in general terms. This is followed by a discussion of the ability to detect a number of specific processes as a function of the SSC energy and luminosity. The viability of various detector technologies is then assessed as a function of luminosity. The report ends with a brief summary and some conclusions

Report of the evaluation by the Ad Hoc Review Committee on High-Temperature Engineering and Research. Result evaluation in fiscal year 2000

International Nuclear Information System (INIS)

2001-06-01

The Research Evaluation Committee, which consisted of 14 members from outside of the Japan Atomic Energy Research Institute (JAERI), set up an Ad Hoc Review Committee on High-Temperature Engineering and Research in accordance with the 'Fundamental Guideline for the Evaluation of Research and Development (R and D) at JAERI' and its subsidiary regulations in order to evaluate the R and D accomplishments achieved for five years from Fiscal Year 1995 to Fiscal Year 1999 at Department of HTTR Project and Department of Advanced Nuclear Heat Technology in Oarai Research Establishment of JAERI. The Ad Hoc Review Committee consisted of nine specialists from outside of JAERI. The Ad Hoc Review Committee conducted its activities from December 2000 to February 2001. The evaluation was performed on the basis of the materials submitted in advanced and of the oral presentations made at the Ad Hoc Review Committee meeting which was held on December 8, 2000, in line with the items, viewpoints, and criteria for the evaluation specified by the Research Evaluation Committee. The result of the evaluation by the Ad Hoc Review Committee was submitted to the Research Evaluation Committee, and was judged to be appropriate at its meeting held on March 16, 2001. This report describes the result of the evaluation by the Ad Hoc Review Committee on High-Temperature Engineering and Research. (author)

Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities

NARCIS (Netherlands)

Sloep, Peter; Kester, Liesbeth; Brouns, Francis; Van Rosmalen, Peter; De Vries, Fred; De Croock, Marcel; Koper, Rob

2007-01-01

Sloep, P.B., Kester, L., Brouns, F., Van Rosmalen, P., De Vries, F., De Croock, M., Koper, R. (2007). Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities. Presentation given at the Sixth IASTED International Conference on Web-based Education, 14-16 March,

A Survey on Trust Management for Mobile Ad Hoc Networks

Science.gov (United States)

2011-11-01

expects, trust is dangerous implying the possible betrayal of trust. In his comments on Lagerspetz’s book titled Trust: The Tacit Demand, Lahno [24...AODV Zouridaki et al. (2005 ) [79] (2006) [80] Secure routing Direct observation [79][80] Reputation by secondhand information [80] Packet dropping...areas of signal processing, wireless communications, sensor and mobile ad hoc networks. He is co-editor of the book Wireless Sensor Networks: Signal

Traffic Agents for Improving QoS in Mixed Infrastructure and Ad Hoc Modes Wireless LAN

Directory of Open Access Journals (Sweden)

Yuan Hai-Feng

2006-01-01

Full Text Available As an important complement to infrastructured wireless networks, mobile ad hoc networks (MANET are more flexible in providing wireless access services, but more difficult in meeting different quality of service (QoS requirements for mobile customers. Both infrastructure and ad hoc network structures are supported in wireless local area networks (WLAN, which can offer high data-rate wireless multimedia services to the mobile stations (MSs in a limited geographical area. For those out-of-coverage MSs, how to effectively connect them to the access point (AP and provide QoS support is a challenging issue. By mixing the infrastructure and the ad hoc modes in WLAN, we propose in this paper a new coverage improvement scheme that can identify suitable idle MSs in good service zones as traffic agents (TAs to relay traffic from those out-of-coverage MSs to the AP. The service coverage area of WLAN is then expanded. The QoS requirements (e.g., bandwidth of those MSs are considered in the selection process of corresponding TAs. Mathematical analysis, verified by computer simulations, shows that the proposed TA scheme can effectively reduce blocking probability when traffic load is light.

On knowledge transfer management as a learning process for ad hoc teams

Science.gov (United States)

Iliescu, D.

2017-08-01

Knowledge management represents an emerging domain becoming more and more important. Concepts like knowledge codification and personalisation, knowledge life-cycle, social and technological dimensions, knowledge transfer and learning management are integral parts. Focus goes here in the process of knowledge transfer for the case of ad hoc teams. The social dimension of knowledge transfer plays an important role. No single individual actors involved in the process, but a collective one, representing the organisation. It is critically important for knowledge to be managed from the life-cycle point of view. A complex communication network needs to be in place to supports the process of knowledge transfer. Two particular concepts, the bridge tie and transactive memory, would eventually enhance the communication. The paper focuses on an informational communication platform supporting the collaborative work on knowledge transfer. The platform facilitates the creation of a topic language to be used in knowledge modelling, storage and reuse, by the ad hoc teams.

Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities

NARCIS (Netherlands)

Sloep, Peter; Kester, Liesbeth; Brouns, Francis; Van Rosmalen, Peter; De Vries, Fred; De Croock, Marcel; Koper, Rob

2007-01-01

Sloep, P.B., Kester, L. Brouns, F., Van Rosmalen, P., De Vries, F., De Croock, M., Koper, R. (2007) Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities. In V. Uskov (Ed.) The Sixth IASTED International Conference on Web-based Education WBE 2007, March 14-16,

A tandem queueing model for delay analysis in disconnected ad hoc networks

NARCIS (Netherlands)

Al Hanbali, Ahmad; de Haan, Roland; Boucherie, Richardus J.; van Ommeren, Jan C.W.

2007-01-01

Ad hoc network routing protocols may fail to operate in the absence of an end-to-end connection from source to destination. This deficiency can be resolved by so-called opportunistic networking which exploits the mobility of the nodes by letting them operate as relays according to the

Model-based prototyping of an interoperability protocol for mobile ad-hoc networks

NARCIS (Netherlands)

Kristensen, L.M.; Westergaard, M.; Norgaard, P.C.; Romijn, J.; Smith, G.; Pol, van de J.

2005-01-01

We present an industrial project conducted at Ericsson Danmark A/S, Telebit where formal methods in the form of Coloured Petri Nets (CP-nets or CPNs) have been used for the specification of an interoperability protocol for routing packets between fixed core networks and mobile ad-hoc networks. The

Energy-aware architecture for multi-rate ad hoc networks

Directory of Open Access Journals (Sweden)

Ahmed Yahya

2010-06-01

Full Text Available The backbone of ad hoc network design is energy performance and bandwidth resources limitations. Multi-rate adaptation architectures have been proposed to reduce the control overhead and to increase bandwidth utilization efficiency. In this paper, we propose a multi-rate protocol to provide the highest network performance under very low control overhead. The efficiency of the proposed auto multi-rate protocol is validated extensive simulations using QualNet network simulator. The simulation results demonstrate that our solution significantly improves the overall network performance.

Adjusting Sensing Range to Maximize Throughput on Ad-Hoc Multi-Hop Wireless Networks

National Research Council Canada - National Science Library

Roberts, Christopher

2003-01-01

.... Such a network is referred to as a multi-hop ad-hoc network, or simply a multi-hop network. Most multi-hop network protocols use some form of carrier sensing to determine if the wireless channel is in use...

Energy-Aware Broadcasting and Multicasting in Wireless Ad Hoc Networks: A Cross-Layering Approach

National Research Council Canada - National Science Library

Wieselthier, Jeffrey E; Nguyen, Gam D; Ephremides, Anthony

2004-01-01

...) problems, especially when energy-aware operation is required. To address the specific problem of energy-aware tree construction in wireless ad hoc networks, we have developed the Broadcast Incremental Power (BIP...

Built-In Device Orientation Sensors for Ad-Hoc Pairing and Spatial Awareness

DEFF Research Database (Denmark)

Grønbæk, Jens Emil; O'Hara, Kenton

Mobile devices are equipped with multiple sensors. The ubiquity of these sensors is key in their ability to support in-the-wild application and use. Building on the ubiquity we look at how we can use this existing sensing infrastructure combined with user mediation to support ad-hoc sharing with ...

Impact of Mobility on the Performance of Relaying in Ad Hoc Networks

NARCIS (Netherlands)

Al Hanbali, Ahmad; Kherani, A.A.; Groenevelt, R.; Nain, P.; Altman, E

2006-01-01

We consider a mobile ad hoc network consisting of three types of nodes: source, destination, and relay nodes. All the nodes are moving over a bounded region with possibly different mobility patterns. We introduce and study the notion of relay throughput, i.e. the maximum rate at which a node can

Improving the Usability of OCL as an Ad-hoc Model Querying Language

DEFF Research Database (Denmark)

Störrle, Harald

2013-01-01

from our research and make it accessible to the OCL community, we propose the OCL Query API (OQAPI), a library of query-predicates to improve the user-friendliness of OCL for ad-hoc querying. The usability of OQAPI is studied using controlled experiments. We nd considerable evidence to support our...

Power-Aware Intrusion Detection in Mobile Ad Hoc Networks

Science.gov (United States)

Şen, Sevil; Clark, John A.; Tapiador, Juan E.

Mobile ad hoc networks (MANETs) are a highly promising new form of networking. However they are more vulnerable to attacks than wired networks. In addition, conventional intrusion detection systems (IDS) are ineffective and inefficient for highly dynamic and resource-constrained environments. Achieving an effective operational MANET requires tradeoffs to be made between functional and non-functional criteria. In this paper we show how Genetic Programming (GP) together with a Multi-Objective Evolutionary Algorithm (MOEA) can be used to synthesise intrusion detection programs that make optimal tradeoffs between security criteria and the power they consume.

RAILWAY INFRASTRUCTURE CAPACITY MANAGEMENT FOR AD-HOC TRAINS ON THE SŽDC NETWORK

Directory of Open Access Journals (Sweden)

Petr Nachtigall

2016-09-01

Full Text Available The paper describes basic principles of ad-hoc routes assignment. Each carrier has its own interface called information system KADR with SŽDC for capacity requests management. The paper describes all steps which must be done before train departure.

An Approach to Ad-hoc Messaging Networks Using Time Shifted Propagation

Directory of Open Access Journals (Sweden)

Christoph Fuchß

2007-10-01

Full Text Available Many communication devices, like mobile phones and PDAs, are enabled for near field communication by using Bluetooth. Many approaches dealt so far with the attempt to transfer mobile ad-hoc networks (MANET to the mechanism of the “fixed internet” to mobile networks. In order to achieve liability and robustness of common TCP connections routing algorithm in near field communication based networks become more sophisticated and complex. These mechanisms often do not reflect on the application’s particularities.Our approach of an ad-hoc messaging network (AMNET uses simple store-and-forward message passing to spread data asynchronously. We do not aim at the reliability of common internet networks but focus on application specific needs that can be covered by simple message passing mechanism. In this paper we will portray a powerful network by using simple devices and communication protocols on the basis of AMNETs. Simulation results of our AMNET approach provide insights towards speeding up the network setup process and to enable the use of AMNETs even with few participants by introducing a hybrid structure of infrastructure and mobile nodes.

Performance and Reliability of DSRC Vehicular Safety Communication: A Formal Analysis

Directory of Open Access Journals (Sweden)

2009-02-01

Full Text Available IEEE- and ASTM-adopted dedicated short range communications (DSRC standard toward 802.11p is a key enabling technology for the next generation of vehicular safety communication. Broadcasting of safety messages is one of the fundamental services in DSRC. There have been numerous publications addressing design and analysis of such broadcast ad hoc system based on the simulations. For the first time, an analytical model is proposed in this paper to evaluate performance and reliability of IEEE 802.11a-based vehicle-to-vehicle (V2V safety-related broadcast services in DSRC system on highway. The proposed model takes two safety services with different priorities, nonsaturated message arrival, hidden terminal problem, fading transmission channel, transmission range, IEEE 802.11 backoff counter process, and highly mobile vehicles on highway into account. Based on the solutions to the proposed analytic model, closed-form expressions of channel throughput, transmission delay, and packet reception rates are derived. From the obtained numerical results under various offered traffic and network parameters, new insights and enhancement suggestions are given.

A Multi-User Game-Theoretical Multipath Routing Protocol to Send Video-Warning Messages over Mobile Ad Hoc Networks.

Science.gov (United States)

Mezher, Ahmad Mohamad; Igartua, Mónica Aguilar; de la Cruz Llopis, Luis J; Pallarès Segarra, Esteve; Tripp-Barba, Carolina; Urquiza-Aguiar, Luis; Forné, Jordi; Sanvicente Gargallo, Emilio

2015-04-17

The prevention of accidents is one of the most important goals of ad hoc networks in smart cities. When an accident happens, dynamic sensors (e.g., citizens with smart phones or tablets, smart vehicles and buses, etc.) could shoot a video clip of the accident and send it through the ad hoc network. With a video message, the level of seriousness of the accident could be much better evaluated by the authorities (e.g., health care units, police and ambulance drivers) rather than with just a simple text message. Besides, other citizens would be rapidly aware of the incident. In this way, smart dynamic sensors could participate in reporting a situation in the city using the ad hoc network so it would be possible to have a quick reaction warning citizens and emergency units. The deployment of an efficient routing protocol to manage video-warning messages in mobile Ad hoc Networks (MANETs) has important benefits by allowing a fast warning of the incident, which potentially can save lives. To contribute with this goal, we propose a multipath routing protocol to provide video-warning messages in MANETs using a novel game-theoretical approach. As a base for our work, we start from our previous work, where a 2-players game-theoretical routing protocol was proposed to provide video-streaming services over MANETs. In this article, we further generalize the analysis made for a general number of N players in the MANET. Simulations have been carried out to show the benefits of our proposal, taking into account the mobility of the nodes and the presence of interfering traffic. Finally, we also have tested our approach in a vehicular ad hoc network as an incipient start point to develop a novel proposal specifically designed for VANETs.

A Multi-User Game-Theoretical Multipath Routing Protocol to Send Video-Warning Messages over Mobile Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Ahmad Mohamad Mezher

2015-04-01

Full Text Available The prevention of accidents is one of the most important goals of ad hoc networks in smart cities. When an accident happens, dynamic sensors (e.g., citizens with smart phones or tablets, smart vehicles and buses, etc. could shoot a video clip of the accident and send it through the ad hoc network. With a video message, the level of seriousness of the accident could be much better evaluated by the authorities (e.g., health care units, police and ambulance drivers rather than with just a simple text message. Besides, other citizens would be rapidly aware of the incident. In this way, smart dynamic sensors could participate in reporting a situation in the city using the ad hoc network so it would be possible to have a quick reaction warning citizens and emergency units. The deployment of an efficient routing protocol to manage video-warning messages in mobile Ad hoc Networks (MANETs has important benefits by allowing a fast warning of the incident, which potentially can save lives. To contribute with this goal, we propose a multipath routing protocol to provide video-warning messages in MANETs using a novel game-theoretical approach. As a base for our work, we start from our previous work, where a 2-players game-theoretical routing protocol was proposed to provide video-streaming services over MANETs. In this article, we further generalize the analysis made for a general number of N players in the MANET. Simulations have been carried out to show the benefits of our proposal, taking into account the mobility of the nodes and the presence of interfering traffic. Finally, we also have tested our approach in a vehicular ad hoc network as an incipient start point to develop a novel proposal specifically designed for VANETs.

Cross-layer model design in wireless ad hoc networks for the Internet of Things.

Science.gov (United States)

Yang, Xin; Wang, Ling; Xie, Jian; Zhang, Zhaolin

2018-01-01

Wireless ad hoc networks can experience extreme fluctuations in transmission traffic in the Internet of Things, which is widely used today. Currently, the most crucial issues requiring attention for wireless ad hoc networks are making the best use of low traffic periods, reducing congestion during high traffic periods, and improving transmission performance. To solve these problems, the present paper proposes a novel cross-layer transmission model based on decentralized coded caching in the physical layer and a content division multiplexing scheme in the media access control layer. Simulation results demonstrate that the proposed model effectively addresses these issues by substantially increasing the throughput and successful transmission rate compared to existing protocols without a negative influence on delay, particularly for large scale networks under conditions of highly contrasting high and low traffic periods.

Cross-layer model design in wireless ad hoc networks for the Internet of Things.

Directory of Open Access Journals (Sweden)

Xin Yang

Full Text Available Wireless ad hoc networks can experience extreme fluctuations in transmission traffic in the Internet of Things, which is widely used today. Currently, the most crucial issues requiring attention for wireless ad hoc networks are making the best use of low traffic periods, reducing congestion during high traffic periods, and improving transmission performance. To solve these problems, the present paper proposes a novel cross-layer transmission model based on decentralized coded caching in the physical layer and a content division multiplexing scheme in the media access control layer. Simulation results demonstrate that the proposed model effectively addresses these issues by substantially increasing the throughput and successful transmission rate compared to existing protocols without a negative influence on delay, particularly for large scale networks under conditions of highly contrasting high and low traffic periods.

The post hoc use of randomised controlled trials to explore drug associated cancer outcomes

DEFF Research Database (Denmark)

Stefansdottir, Gudrun; Zoungas, Sophia; Chalmers, John

2013-01-01

on public health before proper regulatory action can be taken. This paper aims to discuss challenges of exploring drug-associated cancer outcomes by post-hoc analyses of Randomised controlled trials (RCTs) designed for other purposes. METHODOLOGICAL CHALLENGES TO CONSIDER: We set out to perform a post......-hoc nested case-control analysis in the ADVANCE trial in order to examine the association between insulin use and cancer. We encountered several methodological challenges that made the results difficult to interpret, including short duration of exposure of interest, lack of power, and correlation between...... exposure and potential confounders. Considering these challenges, we concluded that using the data would not enlighten the discussion about insulin use and cancer risk and only serve to further complicate any understanding. Therefore, we decided to use our experience to illustrate methodological challenges...

A game-theoretic approach to optimize ad hoc networks inspired by small-world network topology

Science.gov (United States)

Tan, Mian; Yang, Tinghong; Chen, Xing; Yang, Gang; Zhu, Guoqing; Holme, Petter; Zhao, Jing

2018-03-01

Nodes in ad hoc networks are connected in a self-organized manner. Limited communication radius makes information transmit in multi-hop mode, and each forwarding needs to consume the energy of nodes. Insufficient communication radius or exhaustion of energy may cause the absence of some relay nodes and links, further breaking network connectivity. On the other hand, nodes in the network may refuse to cooperate due to objective faulty or personal selfish, hindering regular communication in the network. This paper proposes a model called Repeated Game in Small World Networks (RGSWN). In this model, we first construct ad hoc networks with small-world feature by forming "communication shortcuts" between multiple-radio nodes. Small characteristic path length reduces average forwarding times in networks; meanwhile high clustering coefficient enhances network robustness. Such networks still maintain relative low global power consumption, which is beneficial to extend the network survival time. Then we use MTTFT strategy (Mend-Tolerance Tit-for-Tat) for repeated game as a rule for the interactions between neighbors in the small-world networks. Compared with other five strategies of repeated game, this strategy not only punishes the nodes' selfishness more reasonably, but also has the best tolerance to the network failure. This work is insightful for designing an efficient and robust ad hoc network.

A framework for reactive optimization in mobile ad hoc networks

DEFF Research Database (Denmark)

McClary, Dan; Syrotiuk, Violet; Kulahci, Murat

2008-01-01

We present a framework to optimize the performance of a mobile ad hoc network over a wide range of operating conditions. It includes screening experiments to quantify the parameters and interactions among parameters influential to throughput. Profile-driven regression is applied to obtain a model....... The predictive accuracy of the model is monitored and used to update the model dynamically. The results indicate the framework may be useful for the optimization of dynamic systems of high dimension....

Dynamic fair node spectrum allocation for ad hoc networks using random matrices

Science.gov (United States)

Rahmes, Mark; Lemieux, George; Chester, Dave; Sonnenberg, Jerry

2015-05-01

Dynamic Spectrum Access (DSA) is widely seen as a solution to the problem of limited spectrum, because of its ability to adapt the operating frequency of a radio. Mobile Ad Hoc Networks (MANETs) can extend high-capacity mobile communications over large areas where fixed and tethered-mobile systems are not available. In one use case with high potential impact, cognitive radio employs spectrum sensing to facilitate the identification of allocated frequencies not currently accessed by their primary users. Primary users own the rights to radiate at a specific frequency and geographic location, while secondary users opportunistically attempt to radiate at a specific frequency when the primary user is not using it. We populate a spatial radio environment map (REM) database with known information that can be leveraged in an ad hoc network to facilitate fair path use of the DSA-discovered links. Utilization of high-resolution geospatial data layers in RF propagation analysis is directly applicable. Random matrix theory (RMT) is useful in simulating network layer usage in nodes by a Wishart adjacency matrix. We use the Dijkstra algorithm for discovering ad hoc network node connection patterns. We present a method for analysts to dynamically allocate node-node path and link resources using fair division. User allocation of limited resources as a function of time must be dynamic and based on system fairness policies. The context of fair means that first available request for an asset is not envied as long as it is not yet allocated or tasked in order to prevent cycling of the system. This solution may also save money by offering a Pareto efficient repeatable process. We use a water fill queue algorithm to include Shapley value marginal contributions for allocation.

Performance analysis of differentiated resource-sharing in a wireless ad-hoc network

NARCIS (Netherlands)

Roijers, F.; van den Berg, H.; Mandjes, M.

2010-01-01

In this paper we model and analyze a relay node in a wireless ad-hoc network; the capacity available at this node is used to both transmit traffic from the source nodes (towards the relay node), and to serve traffic at the relay node (so that it can be forwarded to successor nodes). Clearly, a

Fault Tolerant Mechanism for Multimedia Flows in Wireless Ad Hoc Networks Based on Fast Switching Paths

Directory of Open Access Journals (Sweden)

Juan R. Diaz

2014-01-01

Full Text Available Multimedia traffic can be forwarded through a wireless ad hoc network using the available resources of the nodes. Several models and protocols have been designed in order to organize and arrange the nodes to improve transmissions along the network. We use a cluster-based framework, called MWAHCA architecture, which optimizes multimedia transmissions over a wireless ad hoc network. It was proposed by us in a previous research work. This architecture is focused on decreasing quality of service (QoS parameters like latency, jitter, and packet loss, but other network features were not developed, like load balance or fault tolerance. In this paper, we propose a new fault tolerance mechanism, using as a base the MWAHCA architecture, in order to recover any multimedia flow crossing the wireless ad hoc network when there is a node failure. The algorithm can run independently for each multimedia flow. The main objective is to keep the QoS parameters as low as possible. To achieve this goal, the convergence time must be controlled and reduced. This paper provides the designed protocol, the analytical model of the algorithm, and a software application developed to test its performance in a real laboratory.

Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities

OpenAIRE

Sloep, Peter; Kester, Liesbeth; Brouns, Francis; Van Rosmalen, Peter; De Vries, Fred; De Croock, Marcel; Koper, Rob

2007-01-01

Sloep, P.B., Kester, L. Brouns, F., Van Rosmalen, P., De Vries, F., De Croock, M., Koper, R. (2007) Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities. In V. Uskov (Ed.) The Sixth IASTED International Conference on Web-based Education WBE 2007, March 14-16, Chamonix, France (pp. 549-554). Calgary, Canada: Acta Press.

Performance Analysis of Ad Hoc Dispersed Spectrum Cognitive Radio Networks over Fading Channels

Directory of Open Access Journals (Sweden)

Mohammad Muneer

2011-01-01

Full Text Available Cognitive radio systems can utilize dispersed spectrum, and thus such approach is known as dispersed spectrum cognitive radio systems. In this paper, we first provide the performance analysis of such systems over fading channels. We derive the average symbol error probability of dispersed spectrum cognitive radio systems for two cases, where the channel for each frequency diversity band experiences independent and dependent Nakagami- fading. In addition, the derivation is extended to include the effects of modulation type and order by considering M-ary phase-shift keying ( -PSK and M-ary quadrature amplitude modulation -QAM schemes. We then consider the deployment of such cognitive radio systems in an ad hoc fashion. We consider an ad hoc dispersed spectrum cognitive radio network, where the nodes are assumed to be distributed in three dimension (3D. We derive the effective transport capacity considering a cubic grid distribution. Numerical results are presented to verify the theoretical analysis and show the performance of such networks.

Forming an ad-hoc nearby storage, based on IKAROS and social networking services

International Nuclear Information System (INIS)

Filippidis, Christos; Cotronis, Yiannis; Markou, Christos

2014-01-01

We present an ad-hoc 'nearby' storage, based on IKAROS and social networking services, such as Facebook. By design, IKAROS is capable to increase or decrease the number of nodes of the I/O system instance on the fly, without bringing everything down or losing data. IKAROS is capable to decide the file partition distribution schema, by taking on account requests from the user or an application, as well as a domain or a Virtual Organization policy. In this way, it is possible to form multiple instances of smaller capacity higher bandwidth storage utilities capable to respond in an ad-hoc manner. This approach, focusing on flexibility, can scale both up and down and so can provide more cost effective infrastructures for both large scale and smaller size systems. A set of experiments is performed comparing IKAROS with PVFS2 by using multiple clients requests under HPC IOR benchmark and MPICH2.

An Agent-Based Approach To Nodes Misbehaviour Detection In Mobile Ad-Hoc Networks

Directory of Open Access Journals (Sweden)

Otor Samera U.

2017-02-01

Full Text Available Existing Misbehaviour Detection Systems in Mobile Ad-hoc Networks MANETs are challenged with routing overhead and high latency resulting from complexity and failure to isolate and block misbehaving nodes for the reason that it is difficult to detect them as they participate fully in route finding. In this work a Mobile Agent-Based Acknowledgement scheme MAACK was formulated to address this problem using an object oriented algorithm deployed to report misbehaving nodes to the source and destination by registering the Internet Protocol IP address of misbehaving nodes in their header. The scheme was simulated using Network Simulator-3 NS-3 and results benchmarked with an existing scheme the Enhanced Adaptive Acknowledgment EAACK using packet delivery ratio routing overhead and latency as performance metrics in the two scenarios. The results showed that the MAACK paradigm guaranteed a higher packet delivery ratio lower latency and routing overhead than the EAACK scheme. The model can be adapted by Ad-Hoc network protocol developers.

Forming an ad-hoc nearby storage, based on IKAROS and social networking services

Science.gov (United States)

Filippidis, Christos; Cotronis, Yiannis; Markou, Christos

2014-06-01

We present an ad-hoc "nearby" storage, based on IKAROS and social networking services, such as Facebook. By design, IKAROS is capable to increase or decrease the number of nodes of the I/O system instance on the fly, without bringing everything down or losing data. IKAROS is capable to decide the file partition distribution schema, by taking on account requests from the user or an application, as well as a domain or a Virtual Organization policy. In this way, it is possible to form multiple instances of smaller capacity higher bandwidth storage utilities capable to respond in an ad-hoc manner. This approach, focusing on flexibility, can scale both up and down and so can provide more cost effective infrastructures for both large scale and smaller size systems. A set of experiments is performed comparing IKAROS with PVFS2 by using multiple clients requests under HPC IOR benchmark and MPICH2.

The effect of DAD timeout period on address autoconfiguration in wireless ad-hoc networks

CSIR Research Space (South Africa)

Mutanga, MB

2011-09-01

Full Text Available Lack of manual management mechanisms in wireless ad-hoc networks means that automatic configuration of IP addresses and other related network parameters are very crucial. Many IP address autoconfiguration mechanisms have been proposed in literature...

An Economic Framework for Resource Allocation in Ad-hoc Grids

OpenAIRE

Pourebrahimi, B.

2009-01-01

In this dissertation, we present an economic framework to study and develop different market-based mechanisms for resource allocation in an ad-hoc Grid. Such an economic framework helps to understand the impact of certain choices and explores what are the suitable mechanisms from Grid user/owner perspectives under given circumstances. We focus on resource allocation in a Grid-based environment in the case where some resources are lying idle and could be linked with overloaded nodes in a netwo...

Report of the evaluation by the ad hoc review committee on advanced photon and synchrotron radiation research. In-advance evaluation in fiscal year 2001

International Nuclear Information System (INIS)

2001-11-01

The Research Evaluation Committee, which consisted of 13 members from outside of the Japan Atomic Energy Research Institute (JAERI), set up an Ad Hoc Review Committee on Advanced Photon and Synchrotron Radiation Research in accordance with the 'Fundamental Guideline for the Evaluation of Research and Development (R and D) at JAERI' and its subsidiary regulations in order to evaluate the adequacy of the R and D programs to be implemented for five years starting in Fiscal Year 2002 at Advanced Photon Research Center and at Synchrotron Radiation Research Center in Kansai Research Establishment of JAERI. The Ad Hoc Review Committee consisted of ten specialists from outside of JAERI. The Ad Hoc Review Committee conducted its activities from May to July 2001. The evaluation was performed on the basis of the materials submitted in advanced and of the oral presentations made at the Ad Hoc Review Committee meeting which was held on June 21, 2001, in line with the items, viewpoints, and criteria for the evaluation specified by the Research Evaluation Committee. The result of the evaluation by the Ad Hoc Review Committee was submitted to the Research Evaluation Committee, and was judged to be appropriate at its meeting held on July 12, 2001. This report describes the result of the evaluation by the Ad Hoc Review Committee on Advanced Photon and Synchrotron Radiation Research. (author)

On Throughput Improvement of Wireless Ad Hoc Networks with Hidden Nodes

Science.gov (United States)

Choi, Hong-Seok; Lim, Jong-Tae

In this letter, we present the throughput analysis of the wireless ad hoc networks based on the IEEE 802.11 MAC (Medium Access Control). Especially, our analysis includes the case with the hidden node problem so that it can be applied to the multi-hop networks. In addition, we suggest a new channel access control algorithm to maximize the network throughput and show the usefulness of the proposed algorithm through simulations.

Clustering of Mobile Ad Hoc Networks: An Adaptive Broadcast Period Approach

OpenAIRE

Gavalas, Damianos; Pantziou, Grammati; Konstantopoulos, Charalampos; Mamalis, Basilis

2011-01-01

Organization, scalability and routing have been identified as key problems hindering viability and commercial success of mobile ad hoc networks. Clustering of mobile nodes among separate domains has been proposed as an efficient approach to address those issues. In this work, we introduce an efficient distributed clustering algorithm that uses both location and energy metrics for cluster formation. Our proposed solution mainly addresses cluster stability, manageability and energy efficiency i...

Efficacy and safety of maraviroc versus efavirenz, both with zidovudine/lamivudine: 96-week results from the MERIT study.

Science.gov (United States)

Sierra-Madero, Juan; Di Perri, Giovanni; Wood, Robin; Saag, Michael; Frank, Ian; Craig, Charles; Burnside, Robert; McCracken, Jennifer; Pontani, Dennis; Goodrich, James; Heera, Jayvant; Mayer, Howard

2010-01-01

The MERIT study evaluated maraviroc versus efavirenz, both with zidovudine/lamivudine, in treatment-naïve patients with CCR5-tropic (R5) HIV-1. Post hoc analyses previously assessed week 48 outcomes in patients rescreened with R5 virus by a more sensitive tropism assay. Week 96 efficacy (post hoc, n = 614) and safety (n = 721) were assessed. Proportions of subjects <50 copies/mL (58.8% maraviroc, 62.7% efavirenz) and time to loss of virologic response (TLOVR) responders (<50 copies/mL: 60.5% vs 60.7%) were similar. Maraviroc recipients had greater CD4 increases (+ 212 vs + 171 cells/mm(3)) and fewer adverse event discontinuations (6.1% vs 15.5%), malignancies, and category C events. Week 96 data confirm week 48 observations in MERIT.

Throughput Capacity of Ad Hoc Networks with Route Discovery

Directory of Open Access Journals (Sweden)

Blum Rick S

2007-01-01

Full Text Available Throughput capacity of large ad hoc networks has been shown to scale adversely with the size of network . However the need for the nodes to find or repair routes has not been analyzed in this context. In this paper, we explicitly take route discovery into account and obtain the scaling law for the throughput capacity under general assumptions on the network environment, node behavior, and the quality of route discovery algorithms. We also discuss a number of possible scenarios and show that the need for route discovery may change the scaling for the throughput capacity.

Ad-Hoc vs. Standardized and Optimized Arthropod Diversity Sampling

Directory of Open Access Journals (Sweden)

Pedro Cardoso

2009-09-01

Full Text Available The use of standardized and optimized protocols has been recently advocated for different arthropod taxa instead of ad-hoc sampling or sampling with protocols defined on a case-by-case basis. We present a comparison of both sampling approaches applied for spiders in a natural area of Portugal. Tests were made to their efficiency, over-collection of common species, singletons proportions, species abundance distributions, average specimen size, average taxonomic distinctness and behavior of richness estimators. The standardized protocol revealed three main advantages: (1 higher efficiency; (2 more reliable estimations of true richness; and (3 meaningful comparisons between undersampled areas.

New grid based test bed environment for carrying out ad-hoc networking experiments

CSIR Research Space (South Africa)

Johnson, D

2006-09-01

Full Text Available and the third is to do analysis on a real test bed network which has implemented the ad-hoc networking protocol. This paper concerns the third option. Most researchers who have done work on test bed environments have used either indoor Wifi inter-office links...

Assessing Clinical Microbiology Practice Guidelines: American Society for Microbiology Ad Hoc Committee on Evidence-Based Laboratory Medicine Practice Guidelines Assessment.

Science.gov (United States)

Nachamkin, Irving; Kirn, Thomas J; Westblade, Lars F; Humphries, Romney

2017-11-01

As part of the American Society for Microbiology (ASM) Evidence-Based Laboratory Medicine Practice Guidelines Committee of the Professional Practice Committee, an ad hoc committee was formed in 2014 to assess guidelines published by the committee using an assessment tool, Appraisal of Guidelines for Research Evaluation II (AGREE II). The AGREE II assessment helps reviewers determine whether published guidelines are robust, transparent, and clear in presenting practice recommendations in a standardized manner. Identifying strengths and weaknesses of practice guidelines by ad hoc assessments helps with improving future guidelines through the participation of key stakeholders. This minireview describes the development of the ad hoc committee and results from their review of several ASM best practices guidelines and a non-ASM practice guideline from the Emergency Nurses Association. Copyright © 2017 American Society for Microbiology.

Worm epidemics in wireless ad hoc networks

Energy Technology Data Exchange (ETDEWEB)

Nekovee, Maziar [BT Research, Polaris 134, Adastral Park, Martlesham, Suffolk IP5 3RE (United Kingdom); Centre for Computational Science, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom)

2007-06-15

A dramatic increase in the number of computing devices with wireless communication capability has resulted in the emergence of a new class of computer worms which specifically target such devices. The most striking feature of these worms is that they do not require Internet connectivity for their propagation but can spread directly from device to device using a short-range radio communication technology, such as WiFi or Bluetooth. In this paper, we develop a new model for epidemic spreading of these worms and investigate their spreading in wireless ad hoc networks via extensive Monte Carlo simulations. Our studies show that the threshold behaviour and dynamics of worm epidemics in these networks are greatly affected by a combination of spatial and temporal correlations which characterize these networks, and are significantly different from the previously studied epidemics in the Internet.

Worm epidemics in wireless ad hoc networks

Science.gov (United States)

Nekovee, Maziar

2007-06-01

A dramatic increase in the number of computing devices with wireless communication capability has resulted in the emergence of a new class of computer worms which specifically target such devices. The most striking feature of these worms is that they do not require Internet connectivity for their propagation but can spread directly from device to device using a short-range radio communication technology, such as WiFi or Bluetooth. In this paper, we develop a new model for epidemic spreading of these worms and investigate their spreading in wireless ad hoc networks via extensive Monte Carlo simulations. Our studies show that the threshold behaviour and dynamics of worm epidemics in these networks are greatly affected by a combination of spatial and temporal correlations which characterize these networks, and are significantly different from the previously studied epidemics in the Internet.

Worm epidemics in wireless ad hoc networks

International Nuclear Information System (INIS)

Nekovee, Maziar

2007-01-01

A dramatic increase in the number of computing devices with wireless communication capability has resulted in the emergence of a new class of computer worms which specifically target such devices. The most striking feature of these worms is that they do not require Internet connectivity for their propagation but can spread directly from device to device using a short-range radio communication technology, such as WiFi or Bluetooth. In this paper, we develop a new model for epidemic spreading of these worms and investigate their spreading in wireless ad hoc networks via extensive Monte Carlo simulations. Our studies show that the threshold behaviour and dynamics of worm epidemics in these networks are greatly affected by a combination of spatial and temporal correlations which characterize these networks, and are significantly different from the previously studied epidemics in the Internet

Two-terminal reliability analyses for a mobile ad hoc wireless network

International Nuclear Information System (INIS)

Cook, Jason L.; Ramirez-Marquez, Jose Emmanuel

2007-01-01

Reliability is one of the most important performance measures for emerging technologies. For these systems, shortcomings are often overlooked in early releases as the cutting edge technology overshadows a fragile design. Currently, the proliferation of the mobile ad hoc wireless networks (MAWN) is moving from cutting edge to commodity and thus, reliable performance will be expected. Generally, ad hoc networking is applied for the flexibility and mobility it provides. As a result, military and first responders employ this network scheme and the reliability of the network becomes paramount. To ensure reliability is achieved, one must first be able to analyze and calculate the reliability of the MAWN. This work describes the unique attributes of the MAWN and how the classical analysis of network reliability, where the network configuration is known a priori, can be adjusted to model and analyze this type of network. The methods developed acknowledge the dynamic and scalable nature of the MAWN along with its absence of infrastructure. Thus, the methods rely on a modeling approach that considers the probabilistic formation of different network configurations in a MAWN. Hence, this paper proposes reliability analysis methods that consider the effect of node mobility and the continuous changes in the network's connectivity

On Energy-Efficient Hierarchical Cross-Layer Design: Joint Power Control and Routing for Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Poor HVincent

2007-01-01

Full Text Available A hierarchical cross-layer design approach is proposed to increase energy efficiency in ad hoc networks through joint adaptation of nodes' transmitting powers and route selection. The design maintains the advantages of the classic OSI model, while accounting for the cross-coupling between layers, through information sharing. The proposed joint power control and routing algorithm is shown to increase significantly the overall energy efficiency of the network, at the expense of a moderate increase in complexity. Performance enhancement of the joint design using multiuser detection is also investigated, and it is shown that the use of multiuser detection can increase the capacity of the ad hoc network significantly for a given level of energy consumption.

On Energy-Efficient Hierarchical Cross-Layer Design: Joint Power Control and Routing for Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Cristina Comaniciu

2007-03-01

Full Text Available A hierarchical cross-layer design approach is proposed to increase energy efficiency in ad hoc networks through joint adaptation of nodes' transmitting powers and route selection. The design maintains the advantages of the classic OSI model, while accounting for the cross-coupling between layers, through information sharing. The proposed joint power control and routing algorithm is shown to increase significantly the overall energy efficiency of the network, at the expense of a moderate increase in complexity. Performance enhancement of the joint design using multiuser detection is also investigated, and it is shown that the use of multiuser detection can increase the capacity of the ad hoc network significantly for a given level of energy consumption.

Wireless ad hoc and sensor networks management, performance, and applications

CERN Document Server

He, Jing

2013-01-01

Although wireless sensor networks (WSNs) have been employed across a wide range of applications, there are very few books that emphasize the algorithm description, performance analysis, and applications of network management techniques in WSNs. Filling this need, Wireless Ad Hoc and Sensor Networks: Management, Performance, and Applications summarizes not only traditional and classical network management techniques, but also state-of-the-art techniques in this area. The articles presented are expository, but scholarly in nature, including the appropriate history background, a review of current

PUCA: A Pseudonym Scheme with User-Controlled Anonymity for Vehicular Ad-Hoc Networks (VANET)

NARCIS (Netherlands)

Förster, David; Kargl, Frank; Löhr, Hans

2014-01-01

Envisioned vehicular ad-hoc networks (VANET) standards use pseudonym certificates to provide secure and privacy-friendly message authentication. Revocation of long-term credentials is required to remove participants from the system, e.g. in case of vehicle theft. However, the current approach to

FRCA: A Fuzzy Relevance-Based Cluster Head Selection Algorithm for Wireless Mobile Ad-Hoc Sensor Networks

Directory of Open Access Journals (Sweden)

Taegwon Jeong

2011-05-01

Full Text Available Clustering is an important mechanism that efficiently provides information for mobile nodes and improves the processing capacity of routing, bandwidth allocation, and resource management and sharing. Clustering algorithms can be based on such criteria as the battery power of nodes, mobility, network size, distance, speed and direction. Above all, in order to achieve good clustering performance, overhead should be minimized, allowing mobile nodes to join and leave without perturbing the membership of the cluster while preserving current cluster structure as much as possible. This paper proposes a Fuzzy Relevance-based Cluster head selection Algorithm (FRCA to solve problems found in existing wireless mobile ad hoc sensor networks, such as the node distribution found in dynamic properties due to mobility and flat structures and disturbance of the cluster formation. The proposed mechanism uses fuzzy relevance to select the cluster head for clustering in wireless mobile ad hoc sensor networks. In the simulation implemented on the NS-2 simulator, the proposed FRCA is compared with algorithms such as the Cluster-based Routing Protocol (CBRP, the Weighted-based Adaptive Clustering Algorithm (WACA, and the Scenario-based Clustering Algorithm for Mobile ad hoc networks (SCAM. The simulation results showed that the proposed FRCA achieves better performance than that of the other existing mechanisms.

FRCA: a fuzzy relevance-based cluster head selection algorithm for wireless mobile ad-hoc sensor networks.

Science.gov (United States)

Lee, Chongdeuk; Jeong, Taegwon

2011-01-01

Clustering is an important mechanism that efficiently provides information for mobile nodes and improves the processing capacity of routing, bandwidth allocation, and resource management and sharing. Clustering algorithms can be based on such criteria as the battery power of nodes, mobility, network size, distance, speed and direction. Above all, in order to achieve good clustering performance, overhead should be minimized, allowing mobile nodes to join and leave without perturbing the membership of the cluster while preserving current cluster structure as much as possible. This paper proposes a Fuzzy Relevance-based Cluster head selection Algorithm (FRCA) to solve problems found in existing wireless mobile ad hoc sensor networks, such as the node distribution found in dynamic properties due to mobility and flat structures and disturbance of the cluster formation. The proposed mechanism uses fuzzy relevance to select the cluster head for clustering in wireless mobile ad hoc sensor networks. In the simulation implemented on the NS-2 simulator, the proposed FRCA is compared with algorithms such as the Cluster-based Routing Protocol (CBRP), the Weighted-based Adaptive Clustering Algorithm (WACA), and the Scenario-based Clustering Algorithm for Mobile ad hoc networks (SCAM). The simulation results showed that the proposed FRCA achieves better performance than that of the other existing mechanisms.

Performance Analysis of Mobile Ad Hoc Unmanned Aerial Vehicle Communication Networks with Directional Antennas

Directory of Open Access Journals (Sweden)

Abdel Ilah Alshbatat

2010-01-01

Full Text Available Unmanned aerial vehicles (UAVs have the potential of creating an ad hoc communication network in the air. Most UAVs used in communication networks are equipped with wireless transceivers using omnidirectional antennas. In this paper, we consider a collection of UAVs that communicate through wireless links as a mobile ad-hoc network using directional antennas. The network design goal is to maximize the throughput and minimize the end-to-end delay. In this respect, we propose a new medium access control protocol for a network of UAVs with directional antennas. We analyze the communication channel between the UAVs and the effect of aircraft attitude on the network performance. Using the optimized network engineering tool (OPNET, we compare our protocol with the IEEE 802.11 protocol for omnidirectional antennas. The simulation results show performance improvement in end-to-end delay as well as throughput.

Report of the evaluation by the Ad Hoc Review Committee on advance science research. Result evaluation, interim evaluation, in-advance evaluation in fiscal year 2003

International Nuclear Information System (INIS)

2003-11-01

The Research Evaluation Committee, which consisted of 13 members from outside of the Japan Atomic Energy Research Institute (JAERI), set up an Ad Hoc Review Committee on Advanced Science Research in accordance with the Fundamental Guideline for the Evaluation of Research and Development (R and D) at JAERI' and its subsidiary regulations in order to evaluate the accomplishments of the research completed in Fiscal Year 2002, the accomplishments of the research started in Fiscal Year 2001, and the adequacy of the programs of the research to be started in Fiscal Year 2004 at Advanced Science Research Center of JAERI. The Ad Hoc Review Committee consisted of nine specialists from outside of JAERI. The Ad Hoc Review Committee conducted its activities from May to July 2003. The evaluation was performed on the basis of the materials submitted in advance and of the oral presentations made at the Ad Hoc Review Committee meeting which was held on June 24, 2003, in line with the items, viewpoints, and criteria for the evaluation specified by the Research Evaluation Committee. The result of the evaluation by the Ad Hoc Review Committee was submitted to the Research Evaluation Committee, and was judged to be appropriate at its meeting held on August 4, 2003. This report describes the result of the evaluation by the Ad Hoc Review Committee on Advanced Science Research. (author)

Report of the evaluation by the Ad Hoc Review Committee on Advance Science Research. Result evaluation, interim evaluation, in-advance evaluation in fiscal year 2002

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-11-01

The Research Evaluation Committee, which consisted of 13 members from outside of the Japan Atomic Energy Research Institute (JAERI), set up an Ad Hoc Review Committee on Advanced Science Research in accordance with the Fundamental Guideline for the Evaluation of Research and Development (R and D) at JAERI' and its subsidiary regulations in order to evaluate the accomplishments of the research completed in Fiscal Year 2001, the accomplishments of the research started in Fiscal Year 2000, and the adequacy of the programs of the research to be started in Fiscal Year 2003 at Advanced Science Research Center of JAERI. The Ad Hoc Review Committee consisted of eight specialists from outside of JAERI. The Ad Hoc Review Committee conducted its activities from May to July 2002. The evaluation was performed on the basis of the materials submitted in advance and of the oral presentations made at the Ad Hoc Review Committee meeting which was held on June 4, 2002, in line with the items, viewpoints, and criteria for the evaluation specified by the Research Evaluation Committee. The result of the evaluation by the Ad Hoc Review Committee was submitted to the Research Evaluation Committee, and was judged to be appropriate at its meeting held on August 5, 2002. This report describes the result of the evaluation by the Ad Hoc Review Committee on Advanced Science Research. (author)

Tug-of-war model for the two-bandit problem: nonlocally-correlated parallel exploration via resource conservation.

Science.gov (United States)

Kim, Song-Ju; Aono, Masashi; Hara, Masahiko

2010-07-01

We propose a model - the "tug-of-war (TOW) model" - to conduct unique parallel searches using many nonlocally-correlated search agents. The model is based on the property of a single-celled amoeba, the true slime mold Physarum, which maintains a constant intracellular resource volume while collecting environmental information by concurrently expanding and shrinking its branches. The conservation law entails a "nonlocal correlation" among the branches, i.e., volume increment in one branch is immediately compensated by volume decrement(s) in the other branch(es). This nonlocal correlation was shown to be useful for decision making in the case of a dilemma. The multi-armed bandit problem is to determine the optimal strategy for maximizing the total reward sum with incompatible demands, by either exploiting the rewards obtained using the already collected information or exploring new information for acquiring higher payoffs involving risks. Our model can efficiently manage the "exploration-exploitation dilemma" and exhibits good performances. The average accuracy rate of our model is higher than those of well-known algorithms such as the modified -greedy algorithm and modified softmax algorithm, especially, for solving relatively difficult problems. Moreover, our model flexibly adapts to changing environments, a property essential for living organisms surviving in uncertain environments.

Performance Analysis of Routing Protocols in Ad-hoc and Sensor Networking Environments

Directory of Open Access Journals (Sweden)

L. Gavrilovska

2009-06-01

Full Text Available Ad-hoc and sensor networks are becoming an increasingly popular wireless networking concepts lately. This paper analyzes and compares prominent routing schemes in these networking environments. The knowledge obtained can serve users to better understand short range wireless network solutions thus leading to options for implementation in various scenarios. In addition, it should aid researchers develop protocol improvements reliable for the technologies of interest.

Cross-Layer QoS Control for Video Communications over Wireless Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Pei Yong

2005-01-01

Full Text Available Assuming a wireless ad hoc network consisting of homogeneous video users with each of them also serving as a possible relay node for other users, we propose a cross-layer rate-control scheme based on an analytical study of how the effective video transmission rate is affected by the prevailing operating parameters, such as the interference environment, the number of transmission hops to a destination, and the packet loss rate. Furthermore, in order to provide error-resilient video delivery over such wireless ad hoc networks, a cross-layer joint source-channel coding (JSCC approach, to be used in conjunction with rate-control, is proposed and investigated. This approach attempts to optimally apply the appropriate channel coding rate given the constraints imposed by the effective transmission rate obtained from the proposed rate-control scheme, the allowable real-time video play-out delay, and the prevailing channel conditions. Simulation results are provided which demonstrate the effectiveness of the proposed cross-layer combined rate-control and JSCC approach.

A Novel Medium Access Control for Ad hoc Networks Based on OFDM System

Institute of Scientific and Technical Information of China (English)

YU Yi-fan; YIN Chang-chuan; YUE Guang-xin

2005-01-01

Recently, hosts of Medium Access Control (MAC) protocols for Ad hoc radio networks have been proposed to solve the hidden terminal problem and exposed terminal problem. However most of them take into no account the interactions between physical (PHY) system and MAC protocol. Therefore, the current MAC protocols are either inefficient in the networks with mobile nodes and fading channel or difficult in hardware implementation. In this paper, we present a novel media access control for Ad hoc networks that integrates a media access control protocol termed as Dual Busy Tone Multiple Access (DBTMA) into Orthogonal Frequency Division Multiplexing (OFDM) system proposed in IEEE 802.11a standard. The analysis presented in the paper indicates that the proposed MAC scheme achieves performance improvement over IEEE 802.11 protocol about 25%～80% especially in the environment with high mobility and deep fading. The complexity of the proposed scheme is also lower than other implementation of similar busy tone solution. Furthermore, it is compatible with IEEE 802.11a networks.

Level of literacy and dementia: A secondary post-hoc analysis from North-West India

Directory of Open Access Journals (Sweden)

Sunil Kumar Raina

2014-01-01

Full Text Available Introduction: A relation between literacy and dementia has been studied in past and an association has been documented. This is in spite of some studies pointing to the contrary. The current study was aimed at investigating the influence of level of literacy on dementia in a sample stratified by geography (Migrant, Urban, Rural and Tribal areas of sub-Himalayan state of Himachal Pradesh, India. Materials and Methods: The study was based on post-hoc analysis of data obtained from a study conducted on elderly population (60 years and above from selected geographical areas (Migrant, Urban, Rural and Tribal of Himachal Pradesh state in North-west India. Results: Analysis of variance revealed an effect of education on cognitive scores [F = 2.823, P =0.01], however, post-hoc Tukey′s HSD test did not reveal any significant pairwise comparisons. Discussion: The possibility that education effects dementia needs further evaluation, more so in Indian context.

A multihop key agreement scheme for wireless ad hoc networks based on channel characteristics.

Science.gov (United States)

Hao, Zhuo; Zhong, Sheng; Yu, Nenghai

2013-01-01

A number of key agreement schemes based on wireless channel characteristics have been proposed recently. However, previous key agreement schemes require that two nodes which need to agree on a key are within the communication range of each other. Hence, they are not suitable for multihop wireless networks, in which nodes do not always have direct connections with each other. In this paper, we first propose a basic multihop key agreement scheme for wireless ad hoc networks. The proposed basic scheme is resistant to external eavesdroppers. Nevertheless, this basic scheme is not secure when there exist internal eavesdroppers or Man-in-the-Middle (MITM) adversaries. In order to cope with these adversaries, we propose an improved multihop key agreement scheme. We show that the improved scheme is secure against internal eavesdroppers and MITM adversaries in a single path. Both performance analysis and simulation results demonstrate that the improved scheme is efficient. Consequently, the improved key agreement scheme is suitable for multihop wireless ad hoc networks.

Topology Control with Anisotropic and Sector Turning Antennas in Ad-hoc and Sensor Networks

Directory of Open Access Journals (Sweden)

V. Černý

2011-01-01

Full Text Available During the last several years, technological advances have allowed the development of small, cheap, embedded, independent and rather powerful radio devices that can self-organise into data networks. Such networks are usually called ad-hoc networks or, sometimes, depending on the application field, sensor networks. One of the first standards for ad-hoc networks to impose itself as a fully industrial framework for data gathering and control over such devices is IEEE 802.15.4 and, on top of it, its pair network architecture: ZigBee. In the case of multiple radio devices clamped into a small geographical area, the lack of radio bandwidth becomes a major problem, leading to multiple data losses and unnecessary power drain from the batteries of these small devices. This problem is usually perceived as interference. The deployment of appropriate topology control mechanisms (TC can solve interference. All of these algorithms calculate TC on the basis of isotropic antenna radiation patterns in the horizontal plane.

Client-Server and Peer-to-Peer Ad-hoc Network for a Flexible Learning Environment

Directory of Open Access Journals (Sweden)

Ferial Khaddage

2011-01-01

Full Text Available Peer-to-Peer (P2P networking in a mobile learning environment has become a popular topic of research. One of the new emerging research ideas is on the ability to combine P2P network with server-based network to form a strong efficient portable and compatible network infrastructure. This paper describes a unique mobile network architecture, which reflects the on-campus students’ need for a mobile learning environment. This can be achieved by combining two different networks, client-server and peer-to-peer ad-hoc to form a sold and secure network. This is accomplished by employing one peer within the ad-hoc network to act as an agent-peer to facilitate communication and information sharing between the two networks. It can be implemented without any major changes to the current network technologies, and can combine any wireless protocols such as GPRS, Wi-Fi, Bluetooth, and 3G.

Adhoc: an R package to calculate ad hoc distance thresholds for DNA barcoding identification

Directory of Open Access Journals (Sweden)

Gontran Sonet

2013-12-01

Full Text Available Identification by DNA barcoding is more likely to be erroneous when it is based on a large distance between the query (the barcode sequence of the specimen to identify and its best match in a reference barcode library. The number of such false positive identifications can be decreased by setting a distance threshold above which identification has to be rejected. To this end, we proposed recently to use an ad hoc distance threshold producing identifications with an estimated relative error probability that can be fixed by the user (e.g. 5%. Here we introduce two R functions that automate the calculation of ad hoc distance thresholds for reference libraries of DNA barcodes. The scripts of both functions, a user manual and an example file are available on the JEMU website (http://jemu.myspecies.info/computer-programs as well as on the comprehensive R archive network (CRAN, http://cran.r-project.org.

A Family of ACO Routing Protocols for Mobile Ad Hoc Networks

Science.gov (United States)

Rupérez Cañas, Delfín; Sandoval Orozco, Ana Lucila; García Villalba, Luis Javier; Kim, Tai-hoon

2017-01-01

In this work, an ACO routing protocol for mobile ad hoc networks based on AntHocNet is specified. As its predecessor, this new protocol, called AntOR, is hybrid in the sense that it contains elements from both reactive and proactive routing. Specifically, it combines a reactive route setup process with a proactive route maintenance and improvement process. Key aspects of the AntOR protocol are the disjoint-link and disjoint-node routes, separation between the regular pheromone and the virtual pheromone in the diffusion process and the exploration of routes, taking into consideration the number of hops in the best routes. In this work, a family of ACO routing protocols based on AntOR is also specified. These protocols are based on protocol successive refinements. In this work, we also present a parallelized version of AntOR that we call PAntOR. Using programming multiprocessor architectures based on the shared memory protocol, PAntOR allows running tasks in parallel using threads. This parallelization is applicable in the route setup phase, route local repair process and link failure notification. In addition, a variant of PAntOR that consists of having more than one interface, which we call PAntOR-MI (PAntOR-Multiple Interface), is specified. This approach parallelizes the sending of broadcast messages by interface through threads. PMID:28531159

A Family of ACO Routing Protocols for Mobile Ad Hoc Networks.

Science.gov (United States)

Rupérez Cañas, Delfín; Sandoval Orozco, Ana Lucila; García Villalba, Luis Javier; Kim, Tai-Hoon

2017-05-22

In this work, an ACO routing protocol for mobile ad hoc networks based on AntHocNet is specified. As its predecessor, this new protocol, called AntOR, is hybrid in the sense that it contains elements from both reactive and proactive routing. Specifically, it combines a reactive route setup process with a proactive route maintenance and improvement process. Key aspects of the AntOR protocol are the disjoint-link and disjoint-node routes, separation between the regular pheromone and the virtual pheromone in the diffusion process and the exploration of routes, taking into consideration the number of hops in the best routes. In this work, a family of ACO routing protocols based on AntOR is also specified. These protocols are based on protocol successive refinements. In this work, we also present a parallelized version of AntOR that we call PAntOR. Using programming multiprocessor architectures based on the shared memory protocol, PAntOR allows running tasks in parallel using threads. This parallelization is applicable in the route setup phase, route local repair process and link failure notification. In addition, a variant of PAntOR that consists of having more than one interface, which we call PAntOR-MI (PAntOR-Multiple Interface), is specified. This approach parallelizes the sending of broadcast messages by interface through threads.

移动Ad Hoc网络路由协议综述%A Survey of Routing Protocols for Mobile Ad Hoc Networks

Institute of Scientific and Technical Information of China (English)

张顺亮; 叶澄清; 李方敏

2003-01-01

A review of current research about routing protocols for mobile Ad Hoc networks is made. Based on classifying of them, the characteristic, the strength and the weakness of these protocols are evaluated respectively. Then some crucial strategies to improve the existing routing protocols are proposed. Besides, a frame of new routing protocol for Ad Hoc networks is put forward. Finally, open issues that still need investigation are listed.

An Automated Tool for the Creation of Desired Emulated Topologies of a Mobile Ad-Hoc Network

National Research Council Canada - National Science Library

Nguyen, Binh Q

2006-01-01

This report documents a research effort that the U.S. Army Research Laboratory conducted in FY 2005 in support of the development of advanced technologies for tactical mobile ad hoc networks (MANET...

Integrated Social and Quality of Service Trust Management of Mobile Groups in Ad Hoc Networks

Science.gov (United States)

2013-01-01

high resiliency to malicious attacks and misbehaving nodes. Keywords—trust management; mobile ad hoc networks; QoS trust; social trust; trust...paper we address an importance issue of trust management protocol design for MANETs: trust bias minimization despite misbehaving nodes performing

Ad Hoc Microphone Array Beamforming Using the Primal-Dual Method of Multipliers

DEFF Research Database (Denmark)

Tavakoli, Vincent Mohammad; Jensen, Jesper Rindom; Heusdens, Richard

2016-01-01

In the recent years, there have been increasing amount of researches aiming at optimal beamforming with ad hoc microphone arrays, mostly with fusion-based schemes. However, huge amount of computational complexity and communication overhead impede many of these algorithms from being useful in prac...... the distributed linearly-constrained minimum variance beamformer using the the state of the art primal-dual method of multipliers. We study the proposed algorithm with an experiment....

A proposed safety assurance method and its application to the fusion experimental reactor

International Nuclear Information System (INIS)

Okazaki, T.; Seki, Y.; Inabe, T.; Aoki, I.

1995-01-01

Importance categorization and hazard identification methods have been proposed for a fusion experimental reactor. A parameter, the system index, is introduced in the categorization method. The relative importance of systems with safety functions can be classified by the largeness of the system index and whether or not the system acts as a boundary for radioactive materials. This categorization can be used as the basic principle in determining structure design assessment, seismic design criteria etc. For the hazard identification the system time energy matrix is proposed, where the time and spatial distributions of hazard energies are used. This approach is formulated more systematically than an ad-hoc identification of hazard events and it is useful to select design basis events which are employed in the assessment of safety designs. (orig.)

Protocolo W2LAN para transformar una red móvil 802.11 Ad-Hoc (MANET) en una LAN Ethernet

OpenAIRE

Burrull I Mestres, Francesco; García Haro, Juan; Malgosa Sanahuja, José María; Monzó Sánchez, Francisco Miguel

2005-01-01

Las redes MANET (Mobile Ad-Hoc Network) presentan el problema de la visibilidad parcial [1], por lo que hay que considerar protocolos de encaminamiento de nivel de enlace (capa 2 OSI) o superior. Algunos ejemplos de protocolos de encaminamiento en uso podrían ser el protocolo AODV (Ad Hoc On-demand Distance Vector[2]) -reactivo- y DSDV (Destination-Sequenced Distance Vector [3]) -proactivo-. En [4] se puede encontrar una comparativa extensa sobre protocolos de encaminamiento en redes MANET, o...

Spontaneous ad hoc mobile cloud computing network.

Science.gov (United States)

Lacuesta, Raquel; Lloret, Jaime; Sendra, Sandra; Peñalver, Lourdes

2014-01-01

Cloud computing helps users and companies to share computing resources instead of having local servers or personal devices to handle the applications. Smart devices are becoming one of the main information processing devices. Their computing features are reaching levels that let them create a mobile cloud computing network. But sometimes they are not able to create it and collaborate actively in the cloud because it is difficult for them to build easily a spontaneous network and configure its parameters. For this reason, in this paper, we are going to present the design and deployment of a spontaneous ad hoc mobile cloud computing network. In order to perform it, we have developed a trusted algorithm that is able to manage the activity of the nodes when they join and leave the network. The paper shows the network procedures and classes that have been designed. Our simulation results using Castalia show that our proposal presents a good efficiency and network performance even by using high number of nodes.

Specification and Validation of an Edge Router Discovery Protocol for Mobile Ad Hoc Networks

DEFF Research Database (Denmark)

Kristensen, Lars Michael; Jensen, Kurt

2004-01-01

We present an industrial project at Ericsson Telebit A/S where Coloured Petri Nets (CP-nets or CPNs) have been used for the design and specification of an edge router discovery protocol for mobile ad-hoc networks. The Edge Router Discovery Protocol (ERDP) supports an edge router in a stationary...

Impact of mobility on the performance of relaying in ad hoc networks (Extended version)

NARCIS (Netherlands)

Al Hanbali, A.; Kherani, A.A.; Groenevelt, R.; Nain, P.; Altman, E.

2007-01-01

We consider a mobile ad hoc network consisting of three types of nodes: source, destination, and relay nodes. All the nodes are moving over a bounded region with possibly different mobility patterns. We introduce and study the notion of relay throughput, i.e. the maximum rate at which a node can

BLESSED with Opportunistic Beacons: A Lightweight Data Dissemination Model for Smart Mobile Ad-Hoc Networks

NARCIS (Netherlands)

Türkes, Okan; Scholten, Johan; Havinga, Paul J.M.

2015-01-01

This paper introduces BLESSED, a universal opportunistic ad hoc networking model intended for smart mobile devices. It enables fast and lightweight data dissemination in wireless community networks through the complementary utilization of the IEEE 802.11 and Bluetooth Low Energy standards. As a

System optimization for peer-to-peer multi hop video broadcasting in wireless ad hoc networks

NARCIS (Netherlands)

Dedeoglu, V.; Atici, C.; Salman, F.S.; Sunay, M.O.

2008-01-01

We consider peer-to-peer video broadcasting using cooperation among peers in an ad hoc wireless network. As opposed to the traditional single hop broadcasting, multiple hops cause an increase in broadcast video quality while creating interference and increasing transmission delay. We develop

Mobile agents affect worm spreading in wireless ad hoc networks

International Nuclear Information System (INIS)

Huang, Zi-Gang; Sun, Jin-Tu; Wang, Ying-Hai; Wang, Sheng-Jun; Xu, Xin-Jian

2009-01-01

Considering the dynamic nature of portable computing devices with wireless communication capability, an extended model is introduced for worm spreading in the wireless ad hoc network, with a population of mobile agents in a planar distribution, starting from an initial infected seed. The effect of agents' mobility on worm spreading is investigated via extensive Monte Carlo simulations. The threshold behavior and the dynamics of worm epidemics in the wireless networks are greatly affected by both agents' mobility and spatial and temporal correlations. The medium access control mechanism for the wireless communication promotes the sensitivity of the spreading dynamics to agents' mobility

Enhanced Secure Trusted AODV (ESTA Protocol to Mitigate Blackhole Attack in Mobile Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Dilraj Singh

2015-09-01

Full Text Available The self-organizing nature of the Mobile Ad hoc Networks (MANETs provide a communication channel anywhere, anytime without any pre-existing network infrastructure. However, it is exposed to various vulnerabilities that may be exploited by the malicious nodes. One such malicious behavior is introduced by blackhole nodes, which can be easily introduced in the network and, in turn, such nodes try to crumble the working of the network by dropping the maximum data under transmission. In this paper, a new protocol is proposed which is based on the widely used Ad hoc On-Demand Distance Vector (AODV protocol, Enhanced Secure Trusted AODV (ESTA, which makes use of multiple paths along with use of trust and asymmetric cryptography to ensure data security. The results, based on NS-3 simulation, reveal that the proposed protocol is effectively able to counter the blackhole nodes in three different scenarios.

A Safety Enhancement Broadcasting Scheme Based on Context Sensing in VANETs

Directory of Open Access Journals (Sweden)

Chen Chen

2016-01-01

Full Text Available The broadcasting plays a vital role for context awareness in VANETs (Vehicular Ad Hoc Networks whose primary goal is to improve the driving safety depending on effective information exchanging. In this paper, based on the LQG (linear quadratic Gaussian optimal control theory, a broadcasting control scheme named LQG-CCA is proposed to improve the network throughput thus increasing the opportunities for the safety-related events to be successfully handled. By predicting the network throughput with the Kalman filter model, our LQG model is envisioned to minimize the difference between the predicted and expected throughput through the adjustment of CCA (Clear Channel Assessment sensing threshold. Numerical results show that our proposed model can significantly improve the network performance in terms of average throughput, average End-to-End delay, and average packets delivery ratio compared with a highly cited work D-FPAV and a latest published model APPR.

An Incentivized Approach for Fair Participation in Wireless Ad hoc Networks

OpenAIRE

Choudhuri, Arka Rai; S, Kalyanasundaram; Sridhar, Shriyak; B, Annappa

2015-01-01

In Wireless Ad hoc networks (WANETs), nodes separated by considerable distance communicate with each other by relaying their messages through other nodes. However, it might not be in the best interests of a node to forward the message of another node due to power constraints. In addition, all nodes being rational, some nodes may be selfish, i.e. they might not relay data from other nodes so as to increase their lifetime. In this paper, we present a fair and incentivized approach for participa...

Performance Analysis of a Cluster-Based MAC Protocol for Wireless Ad Hoc Networks

Directory of Open Access Journals (Sweden)

Jesús Alonso-Zárate

2010-01-01

Full Text Available An analytical model to evaluate the non-saturated performance of the Distributed Queuing Medium Access Control Protocol for Ad Hoc Networks (DQMANs in single-hop networks is presented in this paper. DQMAN is comprised of a spontaneous, temporary, and dynamic clustering mechanism integrated with a near-optimum distributed queuing Medium Access Control (MAC protocol. Clustering is executed in a distributed manner using a mechanism inspired by the Distributed Coordination Function (DCF of the IEEE 802.11. Once a station seizes the channel, it becomes the temporary clusterhead of a spontaneous cluster and it coordinates the peer-to-peer communications between the clustermembers. Within each cluster, a near-optimum distributed queuing MAC protocol is executed. The theoretical performance analysis of DQMAN in single-hop networks under non-saturation conditions is presented in this paper. The approach integrates the analysis of the clustering mechanism into the MAC layer model. Up to the knowledge of the authors, this approach is novel in the literature. In addition, the performance of an ad hoc network using DQMAN is compared to that obtained when using the DCF of the IEEE 802.11, as a benchmark reference.

Sigsearch: a new term for post hoc unplanned search for statistically significant relationships with the intent to create publishable findings.

Science.gov (United States)

Hashim, Muhammad Jawad

2010-09-01

Post-hoc secondary data analysis with no prespecified hypotheses has been discouraged by textbook authors and journal editors alike. Unfortunately no single term describes this phenomenon succinctly. I would like to coin the term "sigsearch" to define this practice and bring it within the teaching lexicon of statistics courses. Sigsearch would include any unplanned, post-hoc search for statistical significance using multiple comparisons of subgroups. It would also include data analysis with outcomes other than the prespecified primary outcome measure of a study as well as secondary data analyses of earlier research.

Regressive research: The pitfalls of post hoc data selection in the study of unconscious mental processes.

Science.gov (United States)

Shanks, David R

2017-06-01

Many studies of unconscious processing involve comparing a performance measure (e.g., some assessment of perception or memory) with an awareness measure (such as a verbal report or a forced-choice response) taken either concurrently or separately. Unconscious processing is inferred when above-chance performance is combined with null awareness. Often, however, aggregate awareness is better than chance, and data analysis therefore employs a form of extreme group analysis focusing post hoc on participants, trials, or items where awareness is absent or at chance. The pitfalls of this analytic approach are described with particular reference to recent research on implicit learning and subliminal perception. Because of regression to the mean, the approach can mislead researchers into erroneous conclusions concerning unconscious influences on behavior. Recommendations are made about future use of post hoc selection in research on unconscious cognition.

PERFORMANCE ANALYSIS OF DSR ROUTING PROTOCOL UNDER ENERGY BASED SELFISH ATTACK IN MOBILE AD HOC NETWORKS

Directory of Open Access Journals (Sweden)

T.V.P.Sundararajan

2010-06-01

Full Text Available Mobile Ad hoc Networks (MANETs rely on the cooperation of all participating nodes to provide the fundamental operations such as routing and data forwarding. However, due to the open structure and scarcely available battery-based energy, node misbehaviors may exist.[1]. One such routing misbehavior is that some selfish nodes will participate in the route discovery and maintenance processes but refuse to forward data packets. This paper pointed out Energy based selfish nodes (EBSN where these selfish nodes tend to use the network but do not cooperate, saving battery life for their own communications [2],[3]. We present a simulation study of the effects of Energy based selfish nodes (EBSN on DSR routing protocol and its impact over network performance in terms of throughput and delay of a mobile ad hoc network where a defined percentage of nodes were misbehaving.

PROTOCOLS FOR INCREASING THE LIFETIME OF NODES OF AD HOC WIRELESS NETWORKS

Directory of Open Access Journals (Sweden)

B.Malarkodi

2010-03-01

Full Text Available Power consumption of nodes in ad hoc networks is a critical issue as they predominantly operate on batteries. In order to improve the lifetime of an ad hoc network, all the nodes must be utilized evenly and the power required for connections must be minimized. Energy management deals with the process of managing energy resources by means of controlling the battery discharge, adjusting the transmission power and scheduling of power sources so as to increase the lifetime of the nodes of an ad hoc wireless network. In this paper, two protocols are proposed to improve the lifetime of the nodes. The first protocol assumes smart battery packages with L cells and uses dynamic programming (DP to optimally select the set of cells used to satisfy a request for power. The second one proposes a MAC layer protocol denoted as Power Aware medium Access Control (PAMAC protocol which enables the network layer to select a route with minimum total power requirement among the possible routes between a source and a destination provided all nodes in the routes have battery capacity above a threshold. The life time of the nodes using the DP based scheduling policy is found through simulation and compared with that obtained using the techniques reported in the literature. It is found that DP based policy increases the lifetime of the mobile nodes by a factor of 1.15 to 1.8. The life expectancy, the average power consumption and throughput of the network using PAMAC protocol are computed through simulation and compared with that of the other MAC layer protocols 802.11, MACA, and CSMA. Besides this, the life expectancy and average power consumption of the network for different values of threshold are also compared. From the simulation results, it is observed that PAMAC consumes the least power and provides the longest lifetime among the various MAC Layer protocols. Moreover, using PAMAC as the MAC layer protocol, the performance obtained using different routing layer

Comunicaciones seguras sobre redes móviles ad hoc

OpenAIRE

Rocabado Moreno, Sergio Hernán; Arias Figueroa, Daniel; Sánchez, Ernesto

2011-01-01

En este proyecto se ha planteado investigar diferentes mecanismos para realizar comunicaciones seguras utilizando redes móviles ad-hoc, esto permitirá aprovechar las características inherentes de este tipo de redes, para llevar información crítica de forma segura a lugares donde no se disponga de acceso a redes de infraestructura. El resultado final será una propuesta que servirá de base para el desarrollo e implementación de sistemas móviles para emergencias médicas y también como material d...

A Partitioned Approach to Signal Separation with Microphone Ad Hoc Arrays

DEFF Research Database (Denmark)

Tavakoli, Vincent Mohammad; Jensen, Jesper Rindom; Benesty, Jacob

2016-01-01

In this paper, a blind algorithm is proposed for speech enhancement in multi-speaker scenarios, in which interference rejection is the main objective. Here, the ad hoc array is broken into microphone duples which are used to partition the array into local sub-arrays. The core algorithm takes...... advantage of differences in signal structure in each duple. A geometric mean filter is then used to merge the output signals obtained with different duples, and to form a global broadband maximum signal-to-interference ratio (SIR) enhancement apparatus. The resulting filter outputs are enhanced acoustic...

Increased longevity of wireless Ad hoc network through fuzzy system

Directory of Open Access Journals (Sweden)

Fawzia Abdali Larki

2014-06-01

Full Text Available The Ad hoc network is one of the multistep-based self-organizing networks, which are dynamically changing and are taken more into account as the ways of connecting the terminals through the development of wireless communication terminals. We are faced with numerous challenges in designing a wireless network such as the dynamic topology, common and limited bandwidth, and the limited energy. The nodes are moving according to the continuous changes in the topology and the source-to-destination paths are completely broken. Therefore, the repeated route discovery enhances the delay and overload of routing. Thus, it is essential to consider the link stability while designing the path in order to choose the routing protocol. Providing the multiple paths may lead to the better performance than a path. The transmission energy control in the wireless Ad hoc networks is the option for the level of transmission energy in order to transmit each node packet in this system. Therefore, transmission energy control affects the wireless medium interface. Because of choosing the appropriate protocol, the routing operation can be improved and the energy consumption can be controlled properly as well as enhancing the durability and longevity of network. The main objective of this study is to enhance the network longevity. The proposed algorithm in this research considers the combination of 2 parameters including the rate of node energy and number of steps in Fuzzy System applied on AOMDV Protocol, which is a Multipath Routing Protocol. The results of simulation also indicate the improved performance of proposed algorithm (AOMDV-F compared to AODV and AOMDV Protocols in NS2 simulator.

Undilatable Stent Neoatherosclerosis Treated with Ad Hoc Rotational Atherectomy

Directory of Open Access Journals (Sweden)

Michael Koutouzis

2017-01-01

Full Text Available A middle age woman with known ischemic heart disease and old stents in proximal left anterior descending coronary artery (LAD was admitted to Coronary Care Unit with acute coronary syndrome. The coronary angiography showed one vessel disease with significant restenosis within the previously implanted stents. The lesion was tough and remained undilatable despite high pressure balloon inflation. Eventually, the balloon ruptured creating a massive dissection of the LAD beginning immediately after the distal part of the undilatable lesion. We proceeded with a challenging ad hoc rotational atherectomy of the lesion and finally stenting of the lesion. In-stent restenosis many years after stent implantation is considered to be mainly due to neoatheromatosis compared to intimal hyperplasia, making lesion treatment more difficult and unpredictable.

Topology for efficient information dissemination in ad-hoc networking

Science.gov (United States)

Jennings, E.; Okino, C. M.

2002-01-01

In this paper, we explore the information dissemination problem in ad-hoc wirless networks. First, we analyze the probability of successful broadcast, assuming: the nodes are uniformly distributed, the available area has a lower bould relative to the total number of nodes, and there is zero knowledge of the overall topology of the network. By showing that the probability of such events is small, we are motivated to extract good graph topologies to minimize the overall transmissions. Three algorithms are used to generate topologies of the network with guaranteed connectivity. These are the minimum radius graph, the relative neighborhood graph and the minimum spanning tree. Our simulation shows that the relative neighborhood graph has certain good graph properties, which makes it suitable for efficient information dissemination.

33 CFR 175.23 - Serviceable condition.

Science.gov (United States)

2010-07-01

...) Inflator status indicators that are not broken or otherwise non-functional. (d) The inflation system of an...) BOATING SAFETY EQUIPMENT REQUIREMENTS Personal Flotation Devices § 175.23 Serviceable condition. A PFD is... deteriorated structural component that fails when tugged. (b) In addition to meeting the requirements of...

ARSENAL: A Cross Layer Architecture for Secure Resilient Tactical Mobile AdHoc Networks

Science.gov (United States)

2016-01-21

stations separated by 0.5 to 1 km can be coherently measured to a single mobile subscriber using LTE signaling. These are the first measurements of...undertake three parallel but inter-coupled tasks geared towards a) performing measurements via real deployments and enhancing our understanding of layer...dependencies and vulnerabilities in mobile ad hoc networks; these measurements will be on existing testbeds at The views, opinions and/or findings

On results of aseismatic safety examination for atomic energy facilities based on Southern Hyogo Prefecture Earthquake in 1995

International Nuclear Information System (INIS)

1996-01-01

The Nuclear Safety Commission received the report on the results of examination from the ad hoc examination committee. There was no particular effect to atomic energy facilities in the Southern Hyogo Prefecture Earthquake, however, from the viewpoint of perfecting the safety confirmation for atomic energy facilities, the Nuclear Safety Commission set up the aseismatic safety examination committee to investigate the validity of the guidelines related to aseismatic design used for safety examination. The basic plan of the investigation, the outline of the guidelines related to aseismatic design, the state of Southern Hyogo Prefecture Earthquake and the obtained knowledge and the investigation of the validity of the guidelines related to aseismatic design based on the state of Southern Hyogo Prefecture Earthquake are reported. The extraction of the items to be investigated, the evaluation of earthquakes and earthquake motion, vertical earthquake force and active faults, and the way of thinking on right under type earthquakes in the guideline for aseismatic design examination are reported. It was confirmed that the validity of guidelines is not impaired by the earthquake. (K.I.)

Estudio de la topología y protocolos de una red móvil ad-hoc

OpenAIRE

Albalat Montenegro, Bruno

2010-01-01

This project intends to describe how a basic messaging application that, using ad-hoc networks, supports delay tolerance, has been created. Its purpose is to serve as a basis for research groups to be able to work over it for their testing purposes.

MQARR-AODV: A NOVEL MULTIPATH QOS AWARE RELIABLE REVERSE ON-DEMAND DISTANCE VECTOR ROUTING PROTOCOL FOR MOBILE AD-HOC NETWORKS

Directory of Open Access Journals (Sweden)

K.G. Santhiya

2012-12-01

Full Text Available MANET (Mobile Ad-hoc Network is an infra structure less wireless ad-hoc network that does not require any basic central control. The topology of the network changes drastically due to very fast mobility of nodes. So an adaptive routing protocol is needed for routing in MANET. AODV (Ad-hoc On-demand Distance Vector routing is the effective and prominent on-demand Ad-hoc routing protocols. During route establishment phase in traditional AODV, only one route reply message will be sent in the reverse path to establish routing path. The high mobility of nodes may affect the reply messages which lead to the retransmission of route request message by the sender which in turn leads to higher communication delay, power consumption and the reduction in the ratio of packets delivered. Sending multiple route reply messages and establishing multiple paths in a single path discovery will reduce the routing overhead involved in maintaining the connection between source and destination nodes. Multipath routing can render high scalability, end-to-end throughput and provide load balancing in MANET. The new proposed novel Multipath QoS aware reliable routing protocol establishes two routes of maximum node disjoint paths and the data transfer is carried out in the two paths simultaneously. To select best paths, the new proposed protocol uses three parameters Link Eminence, MAC overhead and node residual energy. The experimental values prove that the MQARR-AODV protocol achieves high reliability, stability, low latency and outperforms AODV by the less energy consumption, overhead and delay.

Improving TCP Performance over Wireless Ad Hoc Networks with Busy Tone Assisted Scheme

Directory of Open Access Journals (Sweden)

Cai Lin

2006-01-01

Full Text Available It is well known that transmission control protocol (TCP performance degrades severely in IEEE 802.11-based wireless ad hoc networks. We first identify two critical issues leading to the TCP performance degradation: (1 unreliable broadcast, since broadcast frames are transmitted without the request-to-send and clear-to-send (RTS/CTS dialog and Data/ACK handshake, so they are vulnerable to the hidden terminal problem; and (2 false link failure which occurs when a node cannot successfully transmit data temporarily due to medium contention. We then propose a scheme to use a narrow-bandwidth, out-of-band busy tone channel to make reservation for broadcast and link error detection frames only. The proposed scheme is simple and power efficient, because only the sender needs to transmit two short messages in the busy tone channel before sending broadcast or link error detection frames in the data channel. Analytical results show that the proposed scheme can dramatically reduce the collision probability of broadcast and link error detection frames. Extensive simulations with different network topologies further demonstrate that the proposed scheme can improve TCP throughput by 23% to 150%, depending on user mobility, and effectively enhance both short-term and long-term fairness among coexisting TCP flows in multihop wireless ad hoc networks.

Neuroprotection as initial therapy in acute stroke - Third report of an Ad Hoc Consensus Group Meeting

NARCIS (Netherlands)

Bogousslavsky, J; De Keyser, J; Diener, HC; Fieschi, C; Hacke, W; Kaste, M; Orgogozo, JM; Pulsinelli, W; Wahlgren, NG

1998-01-01

Although a considerable body of scientific data is now available on neuroprotection in acute ischaemic stroke, this field is not yet established in clinical practice. At its third meeting, the European Ad Hoc Consensus Group considered the potential for neuroprotection in acute stroke and the

The doctrine of joint criminal action in the ad hoc tribunals and its scope in the Rome Statute

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Miren Odriozola-Gurrutxaga

2014-03-01

Full Text Available The first judgment of the International Criminal Court has confirmed that article 25 (3 of the Rome Statute adopts the theory of control of the act to distinguish between principals and accessories. On the contrary, since 2003, the ad hoc tribunals’ case law bases the notion of co-perpetration on the Joint Criminal Enterprise doctrine, using a subjective criterion approach. In this article we will first analyze the problems raised by that case law of the ad hoc tribunals, and then, we will study the article of the Rome Statute which apparently most resembles the Joint Criminal Enterprise doctrine: article 25 (3 (d. The article concludes that none of the three categories of that doctrine is included in the said provision.

Adaptive Probabilistic Broadcasting over Dense Wireless Ad Hoc Networks

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Victor Gau

2010-01-01

Full Text Available We propose an idle probability-based broadcasting method, iPro, which employs an adaptive probabilistic mechanism to improve performance of data broadcasting over dense wireless ad hoc networks. In multisource one-hop broadcast scenarios, the modeling and simulation results of the proposed iPro are shown to significantly outperform the standard IEEE 802.11 under saturated condition. Moreover, the results also show that without estimating the number of competing nodes and changing the contention window size, the performance of the proposed iPro can still approach the theoretical bound. We further apply iPro to multihop broadcasting scenarios, and the experiment results show that within the same elapsed time after the broadcasting, the proposed iPro has significantly higher Packet-Delivery Ratios (PDR than traditional methods.

miRNA-mediated 'tug-of-war' model reveals ceRNA propensity of genes in cancers.

Science.gov (United States)

Swain, Arpit Chandan; Mallick, Bibekanand

2018-06-01

Competing endogenous RNA (ceRNA) are transcripts that cross-regulate each other at the post-transcriptional level by competing for shared microRNA response elements (MREs). These have been implicated in various biological processes impacting cell-fate decisions and diseases including cancer. There are several studies that predict possible ceRNA pairs by adopting various machine-learning and mathematical approaches; however, there is no method that enables us to gauge as well as compare the propensity of the ceRNA of a gene and precisely envisages which among a pair exerts a stronger pull on the shared miRNA pool. In this study, we developed a method that uses the 'tug of war of genes' concept to predict and quantify ceRNA potential of a gene for the shared miRNA pool in cancers based on a score represented by SoCeR (score of competing endogenous RNA). The method was executed on the RNA-Seq transcriptional profiles of genes and miRNA available at TCGA along with CLIP-supported miRNA-target sites to predict ceRNA in 32 cancer types which were validated with already reported cases. The proposed method can be used to determine the sequestering capability of the gene of interest as well as in ranking the probable ceRNA candidates of a gene. Finally, we developed standalone applications (SoCeR tool) to aid researchers in easier implementation of the method in analysing different data sets or diseases. © 2018 The Authors. Published by FEBS Press and John Wiley & Sons Ltd.

Secure and Usable Out-Of-Band Channels for Ad Hoc Mobile Device Interactions

OpenAIRE

Kainda , Ronald; Flechais , Ivan; Roscoe , A. W.

2010-01-01

International audience; Protocols for bootstrapping security in ad hoc mobile device interactions rely on users' ability to perform specific tasks such as transferring or comparing fingerprints of information between devices. The size of fingerprints depends on the level of technical security required by a given application but, at the same time, is limited by users' inability to deal with large amounts of data with high levels of accuracy. Large fingerprints provide high technical security b...

Intelligent QoS routing algorithm based on improved AODV protocol for Ad Hoc networks

Science.gov (United States)

Huibin, Liu; Jun, Zhang

2016-04-01

Mobile Ad Hoc Networks were playing an increasingly important part in disaster reliefs, military battlefields and scientific explorations. However, networks routing difficulties are more and more outstanding due to inherent structures. This paper proposed an improved cuckoo searching-based Ad hoc On-Demand Distance Vector Routing protocol (CSAODV). It elaborately designs the calculation methods of optimal routing algorithm used by protocol and transmission mechanism of communication-package. In calculation of optimal routing algorithm by CS Algorithm, by increasing QoS constraint, the found optimal routing algorithm can conform to the requirements of specified bandwidth and time delay, and a certain balance can be obtained among computation spending, bandwidth and time delay. Take advantage of NS2 simulation software to take performance test on protocol in three circumstances and validate the feasibility and validity of CSAODV protocol. In results, CSAODV routing protocol is more adapt to the change of network topological structure than AODV protocol, which improves package delivery fraction of protocol effectively, reduce the transmission time delay of network, reduce the extra burden to network brought by controlling information, and improve the routing efficiency of network.

Panel Discussion : Report of the APS Ad-Hoc Committee on LGBT Issues

Science.gov (United States)

Atherton, Tim; Barthelemy, Ramon; Garmon, Savannah; Reeves, Kyle; APS Ad-Hoc Committee on LGBT Issues Team

Following the presentation of the findings and recommendations of the APS Ad-Hoc Committee on LGBT Issues (C-LGBT) by Committee Chair Michael Falk, a panel discussion will be held featuring several members of the committee. The discussion will focus on how APS can best ensure the recommendations of the committee are carried out in a timely fashion and other ideas on future APS efforts toward LGBT inclusion in physics. Discussion topics will also include the research and other input that shaped the committee's findings and recommendations.

Enabling Real-Time Video Services over Ad-Hoc Networks Opens the Gates for E-learning in Areas Lacking Infrastructure

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Johannes Karlsson

2009-10-01

Full Text Available In this paper we suggest a promising solution to come over the problems of delivering e-learning to areas with lack or deficiencies in infrastructure for Internet and mobile communication. We present a simple, reasonably priced and efficient communication platform for providing e-learning. This platform is based on wireless ad-hoc networks. We also present a preemptive routing protocol suitable for real-time video communication over wireless ad-hoc networks. Our results show that this routing protocol can significantly improve the quality of the received video. This makes our suggested system not only good to overcome the infrastructure barrier but even capable of delivering a high quality e-learning material.

Vehicular ad hoc networks standards, solutions, and research

CERN Document Server

Molinaro, Antonella; Scopigno, Riccardo

2015-01-01

This book presents vehicular ad-hoc networks (VANETs) from the their onset, gradually going into technical details, providing a clear understanding of both theoretical foundations and more practical investigation. The editors gathered top-ranking authors to provide comprehensiveness and timely content; the invited authors were carefully selected from a list of who’s who in the respective field of interest: there are as many from Academia as from Standardization and Industry sectors from around the world. The covered topics are organized around five Parts starting from an historical overview of vehicular communications and standardization/harmonization activities (Part I), then progressing to the theoretical foundations of VANETs and a description of the day-one standard-compliant solutions (Part II), hence going into details of vehicular networking and security (Part III) and to the tools to study VANETs, from mobility and channel models, to network simulators and field trial methodologies (Part IV), and fi...

Data management issues in mobile ad hoc networks.

Science.gov (United States)

Hara, Takahiro

2017-01-01

Research on mobile ad hoc networks (MANETs) has become a hot research topic since the middle 1990's. Over the first decade, most research focused on networking techniques, ignoring data management issues. We, however, realized early the importance of data management in MANETs, and have been conducting studies in this area for 15 years. In this review, we summarize some key technical issues related to data management in MANETs, and the studies we have done in addressing these issues, which include placement of data replicas, update management, and query processing with security management. The techniques proposed in our studies have been designed with deep considerations of MANET features including network partitioning, node participation/disappearance, limited network bandwidth, and energy efficiency. Our studies published in early 2000's have developed a new research field as data management in MANETs. Also, our recent studies are expected to be significant guidelines of new research directions. We conclude the review by discussing some future directions for research.

Intelligent self-organization methods for wireless ad hoc sensor networks based on limited resources

Science.gov (United States)

Hortos, William S.

2006-05-01

A wireless ad hoc sensor network (WSN) is a configuration for area surveillance that affords rapid, flexible deployment in arbitrary threat environments. There is no infrastructure support and sensor nodes communicate with each other only when they are in transmission range. To a greater degree than the terminals found in mobile ad hoc networks (MANETs) for communications, sensor nodes are resource-constrained, with limited computational processing, bandwidth, memory, and power, and are typically unattended once in operation. Consequently, the level of information exchange among nodes, to support any complex adaptive algorithms to establish network connectivity and optimize throughput, not only deplete those limited resources and creates high overhead in narrowband communications, but also increase network vulnerability to eavesdropping by malicious nodes. Cooperation among nodes, critical to the mission of sensor networks, can thus be disrupted by the inappropriate choice of the method for self-organization. Recent published contributions to the self-configuration of ad hoc sensor networks, e.g., self-organizing mapping and swarm intelligence techniques, have been based on the adaptive control of the cross-layer interactions found in MANET protocols to achieve one or more performance objectives: connectivity, intrusion resistance, power control, throughput, and delay. However, few studies have examined the performance of these algorithms when implemented with the limited resources of WSNs. In this paper, self-organization algorithms for the initiation, operation and maintenance of a network topology from a collection of wireless sensor nodes are proposed that improve the performance metrics significant to WSNs. The intelligent algorithm approach emphasizes low computational complexity, energy efficiency and robust adaptation to change, allowing distributed implementation with the actual limited resources of the cooperative nodes of the network. Extensions of the

Anaesthetic management of emergency pacemaker implantation in a case of neonatal lupus erythematosus with complete congenital heart block & severe respiratory distress

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Usha Kiran

2007-01-01

Full Text Available An 8-week old 3-kilogram male baby was brought to this tertiary care hospital with respiratory distress, marked tracheal tug, poor feeding and a heart rate of 46/minute. The child had been referred from a peripheral hospital as a case of neonatal lupus with complete congenital heart block. The mother was seropositive for systemic lupus erythematosus with a history of two abortions. Evaluation on admission revealed a heart rate between 40-60/ minute, respiratory rate 40-50/ minute, inspiratory stridor, bilateral crepitations, chest retrac-tion and a marked tracheal tug that improved with prone positioning. Electrocardiography and echocardiography confirmed complete congenital heart block with cardiomegaly and mild left ventricular dysfunction. Keeping in view the impending congestive heart failure, possible early cardiomyopathy and the bad obstetric history ur-gent pacemaker implantation was planned to allow early recovery of the child. The anaesthetic risk was high due to the heart block, ventricular dysfunction, laryngomalacia, severe tracheal tug and anticipated difficult weaning from controlled ventilation. General anaesthesia was administered with endotracheal tube and con-trolled ventilation using ketamine, rocuronium and sufentanil. For patient safety invasive monitoring was pro-vided and external pacing was kept standby. Epicardial pacemaker leads were implanted onto the left ventricu-lar wall through a left anterior 6th intercostal space thoracotomy. The child was electively ventilated for two post operative days. The tracheal tug and secretions gradually subsided over 2 weeks with oxygen, antibiotics, steroids, bronchodilators and physiotherapy. At the time of discharge from hospital 2 weeks after the implant the child was feeding well, tracheal tug was minimal and the lungs were clear.

A Game Theory Based Approach for Power Efficient Vehicular Ad Hoc Networks

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Kun Hua

2017-01-01

Full Text Available Green communications are playing critical roles in vehicular ad hoc networks (VANETs, while the deployment of a power efficient VANET is quite challenging in practice. To add more greens into such kind of complicated and time-varying mobile network, we specifically investigate the throughput and transmission delay performances for real-time and delay sensitive services through a repeated game theoretic solution. This paper has employed Nash Equilibrium in the noncooperative game model and analyzes its efficiency. Simulation results have shown an obvious improvement on power efficiency through such efforts.

Body position and motor imagery strategy effects on imagining gait in healthy adults: Results from a cross-sectional study.

Science.gov (United States)

Beauchet, Olivier; Launay, Cyrille P; Sekhon, Harmehr; Gautier, Jennifer; Chabot, Julia; Levinoff, Elise J; Allali, Gilles

2018-01-01

Assessment of changes in higher levels of gait control with aging is important to better understand age-related gait instability, with the perspective to improve the screening of individuals at risk for falls. The comparison between actual Timed Up and Go test (aTUG) and its imagined version (iTUG) is a simple clinical way to assess age-related changes in gait control. The modulations of iTUG performances by body positions and motor imagery (MI) strategies with normal aging have not been evaluated yet. This study aims 1) to compare the aTUG time with the iTUG time under different body positions (i.e., sitting, standing or supine) in healthy young and middle age, and older adults, and 2) to examine the associations of body positions and MI strategies (i.e., egocentric versus allocentric) with the time needed to complete the iTUG and the delta TUG time (i.e., relative difference between aTUG and iTUG) while taking into consideration clinical characteristics of participants. A total of 60 healthy individuals (30 young and middle age participants 26.6±7.4 years, and 30 old participants 75.0±4.4 years) were recruited in this cross-sectional study. The iTUG was performed while sitting, standing and in supine position. Times of the aTUG, the iTUG under the three body positions, the TUG delta time and the strategies of MI (i.e., ego representation, defined as representation of the location of objects in space relative to the body axes of the self, versus allocentric representation defined as encoding information about body movement with respect to other object, the location of body being defined relative to the location of other objects) were used as outcomes. Age, sex, height, weight, number of drugs taken daily, level of physical activity and prevalence of closed eyes while performing iTUG were recorded. The aTUG time is significantly greater than iTUG while sitting and standing (Pposition. The multiple linear regressions confirm that the supine position is associated

Implementation and Evaluation of Multichannel Multi-Interface Routing Mechanism with QoS-Consideration for Ad-Hoc Networks

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Satoh Hiroki

2010-01-01

Full Text Available To accommodate real-time multimedia application while satisfying application-level QoS requirements in a wireless ad-hoc network, we need QoS control mechanisms. We proposed a new routing mechanism for a wireless ad-hoc network composed of nodes equipped with multiple network interfaces. By embedding information about channel usage in control messages of OLSRv2, each node obtains a view of topology and bandwidth information of the whole network. Based on the obtained information, a source node determines a logical path with the maximum available bandwidth to satisfy application-level QoS requirements. In this paper, we evaluated feasibility of the proposal through simulation and practical experiments and confirmed that our proposal effectively transferred multimedia packets over a logical path avoiding congested links. The load on a network is well distributed and the network can accommodate more sessions than OLSRv2 and QOLSR.

Amoeba-inspired Tug-of-War algorithms for exploration-exploitation dilemma in extended Bandit Problem.

Science.gov (United States)

Aono, Masashi; Kim, Song-Ju; Hara, Masahiko; Munakata, Toshinori

2014-03-01

The true slime mold Physarum polycephalum, a single-celled amoeboid organism, is capable of efficiently allocating a constant amount of intracellular resource to its pseudopod-like branches that best fit the environment where dynamic light stimuli are applied. Inspired by the resource allocation process, the authors formulated a concurrent search algorithm, called the Tug-of-War (TOW) model, for maximizing the profit in the multi-armed Bandit Problem (BP). A player (gambler) of the BP should decide as quickly and accurately as possible which slot machine to invest in out of the N machines and faces an "exploration-exploitation dilemma." The dilemma is a trade-off between the speed and accuracy of the decision making that are conflicted objectives. The TOW model maintains a constant intracellular resource volume while collecting environmental information by concurrently expanding and shrinking its branches. The conservation law entails a nonlocal correlation among the branches, i.e., volume increment in one branch is immediately compensated by volume decrement(s) in the other branch(es). Owing to this nonlocal correlation, the TOW model can efficiently manage the dilemma. In this study, we extend the TOW model to apply it to a stretched variant of BP, the Extended Bandit Problem (EBP), which is a problem of selecting the best M-tuple of the N machines. We demonstrate that the extended TOW model exhibits better performances for 2-tuple-3-machine and 2-tuple-4-machine instances of EBP compared with the extended versions of well-known algorithms for BP, the ϵ-Greedy and SoftMax algorithms, particularly in terms of its short-term decision-making capability that is essential for the survival of the amoeba in a hostile environment. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Impact of mobility on the performance7 of relaying in ad hoc networks – Extended version

NARCIS (Netherlands)

Al Hanbali, Ahmad; Kherani, A.A.; Groenevelt, R.; Nain, P.; Altman, E

2007-01-01

We consider a mobile ad hoc network consisting of three types of nodes: source, destination, and relay nodes. All the nodes are moving over a bounded region with possibly different mobility patterns. We introduce and study the notion of relay throughput, i.e. the maximum rate at which a node can

Intelligent Networks Data Fusion Web-based Services for Ad-hoc Integrated WSNs-RFID

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Falah Alshahrany

2016-01-01

Full Text Available The use of variety of data fusion tools and techniques for big data processing poses the problem of the data and information integration called data fusion having objectives which can differ from one application to another. The design of network data fusion systems aimed at meeting these objectives, need to take into account of the necessary synergy that can result from distributed data processing within the data networks and data centres, involving increased computation and communication. This papers reports on how this processing distribution is functionally structured as configurable integrated web-based support services, in the context of an ad-hoc wireless sensor network used for sensing and tracking, in the context of distributed detection based on complete observations to support real rime decision making. The interrelated functional and hardware RFID-WSN integration is an essential aspect of the data fusion framework that focuses on multi-sensor collaboration as an innovative approach to extend the heterogeneity of the devices and sensor nodes of ad-hoc networks generating a huge amount of heterogeneous soft and hard raw data. The deployment and configuration of these networks require data fusion processing that includes network and service management and enhances the performance and reliability of networks data fusion support systems providing intelligent capabilities for real-time control access and fire detection.

Optimalization of Beacon Selection for Localization in Wireless AD-HOC Networks

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Martin Matula

2008-01-01

Full Text Available In this paper we engage in optimalization of convenient beacons for localization position of a node in the ad-hoc network. An algorithm designed by us localizes position of moving or static node by RSS (Received Signal Strength method and trilateration. At first, localization of unknown node runs by combination of all beacons. Than optimalizating algorithmreduces the number of beacons (and repeats localization, while only three left. Its reduction is based on highest levels of received signal strength. It is only when signals are from the nearest beacons. Position localizating exactness is statistically interpreted from all localization by beacons combination and its repeating.

Intelligent Security Auditing Based on Access Control of Devices in Ad Hoc Network

Institute of Scientific and Technical Information of China (English)

XU Guang-wei; SHI You-qun; ZHU Ming; WU Guo-wen; CAO Qi-ying

2006-01-01

Security in Ad Hoc network is an important issue under the opening circumstance of application service. Some protocols and models of security auditing have been proposed to ensure rationality of contracting strategy and operating regulation and used to identify abnormal operation. Model of security auditing based on access control of devices will be advanced to register sign of devices and property of event of access control and to audit those actions. In the end, the model is analyzed and simulated.

Mobility Models for Next Generation Wireless Networks Ad Hoc, Vehicular and Mesh Networks

CERN Document Server

Santi, Paolo

2012-01-01

Mobility Models for Next Generation Wireless Networks: Ad Hoc, Vehicular and Mesh Networks provides the reader with an overview of mobility modelling, encompassing both theoretical and practical aspects related to the challenging mobility modelling task. It also: Provides up-to-date coverage of mobility models for next generation wireless networksOffers an in-depth discussion of the most representative mobility models for major next generation wireless network application scenarios, including WLAN/mesh networks, vehicular networks, wireless sensor networks, and

Embedded Disposable Functionalized Electrochemical Biosensor with a 3D-Printed Flow Cell for Detection of Hepatic Oval Cells (HOCs

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Samar Damiati

2018-02-01

Full Text Available Hepatic oval cells (HOCs are considered the progeny of the intrahepatic stem cells that are found in a small population in the liver after hepatocyte proliferation is inhibited. Due to their small number, isolation and capture of these cells constitute a challenging task for immunosensor technology. This work describes the development of a 3D-printed continuous flow system and exploits disposable screen-printed electrodes for the rapid detection of HOCs that over-express the OV6 marker on their membrane. Multiwall carbon nanotube (MWCNT electrodes have a chitosan film that serves as a scaffold for the immobilization of oval cell marker antibodies (anti-OV6-Ab, which enhance the sensitivity of the biomarker and makes the designed sensor specific for oval cells. The developed sensor can be easily embedded into the 3D-printed flow cell to allow cells to be exposed continuously to the functionalized surface. The continuous flow is intended to increase capture of most of the target cells in the specimen. Contact angle measurements were performed to characterize the nature and quality of the modified sensor surface, and electrochemical measurements (cyclic voltammetry (CV and square wave voltammetry (SWV were performed to confirm the efficiency and selectivity of the fabricated sensor to detect HOCs. The proposed method is valuable for capturing rare cells and could provide an effective tool for cancer diagnosis and detection.

Embedded Disposable Functionalized Electrochemical Biosensor with a 3D-Printed Flow Cell for Detection of Hepatic Oval Cells (HOCs)

Science.gov (United States)

Peacock, Martin; Leonhardt, Stefan; Damiati, Laila; Baghdadi, Mohammed A.; Schuster, Bernhard

2018-01-01

Hepatic oval cells (HOCs) are considered the progeny of the intrahepatic stem cells that are found in a small population in the liver after hepatocyte proliferation is inhibited. Due to their small number, isolation and capture of these cells constitute a challenging task for immunosensor technology. This work describes the development of a 3D-printed continuous flow system and exploits disposable screen-printed electrodes for the rapid detection of HOCs that over-express the OV6 marker on their membrane. Multiwall carbon nanotube (MWCNT) electrodes have a chitosan film that serves as a scaffold for the immobilization of oval cell marker antibodies (anti-OV6-Ab), which enhance the sensitivity of the biomarker and makes the designed sensor specific for oval cells. The developed sensor can be easily embedded into the 3D-printed flow cell to allow cells to be exposed continuously to the functionalized surface. The continuous flow is intended to increase capture of most of the target cells in the specimen. Contact angle measurements were performed to characterize the nature and quality of the modified sensor surface, and electrochemical measurements (cyclic voltammetry (CV) and square wave voltammetry (SWV)) were performed to confirm the efficiency and selectivity of the fabricated sensor to detect HOCs. The proposed method is valuable for capturing rare cells and could provide an effective tool for cancer diagnosis and detection. PMID:29443890

Embedded Disposable Functionalized Electrochemical Biosensor with a 3D-Printed Flow Cell for Detection of Hepatic Oval Cells (HOCs).

Science.gov (United States)

Damiati, Samar; Peacock, Martin; Leonhardt, Stefan; Damiati, Laila; Baghdadi, Mohammed A; Becker, Holger; Kodzius, Rimantas; Schuster, Bernhard

2018-02-14

Hepatic oval cells (HOCs) are considered the progeny of the intrahepatic stem cells that are found in a small population in the liver after hepatocyte proliferation is inhibited. Due to their small number, isolation and capture of these cells constitute a challenging task for immunosensor technology. This work describes the development of a 3D-printed continuous flow system and exploits disposable screen-printed electrodes for the rapid detection of HOCs that over-express the OV6 marker on their membrane. Multiwall carbon nanotube (MWCNT) electrodes have a chitosan film that serves as a scaffold for the immobilization of oval cell marker antibodies (anti-OV6-Ab), which enhance the sensitivity of the biomarker and makes the designed sensor specific for oval cells. The developed sensor can be easily embedded into the 3D-printed flow cell to allow cells to be exposed continuously to the functionalized surface. The continuous flow is intended to increase capture of most of the target cells in the specimen. Contact angle measurements were performed to characterize the nature and quality of the modified sensor surface, and electrochemical measurements (cyclic voltammetry (CV) and square wave voltammetry (SWV)) were performed to confirm the efficiency and selectivity of the fabricated sensor to detect HOCs. The proposed method is valuable for capturing rare cells and could provide an effective tool for cancer diagnosis and detection.

Building Realistic Mobility Models for Mobile Ad Hoc Networks

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Adrian Pullin

2018-04-01

Full Text Available A mobile ad hoc network (MANET is a self-configuring wireless network in which each node could act as a router, as well as a data source or sink. Its application areas include battlefields and vehicular and disaster areas. Many techniques applied to infrastructure-based networks are less effective in MANETs, with routing being a particular challenge. This paper presents a rigorous study into simulation techniques for evaluating routing solutions for MANETs with the aim of producing more realistic simulation models and thereby, more accurate protocol evaluations. MANET simulations require models that reflect the world in which the MANET is to operate. Much of the published research uses movement models, such as the random waypoint (RWP model, with arbitrary world sizes and node counts. This paper presents a technique for developing more realistic simulation models to test and evaluate MANET protocols. The technique is animation, which is applied to a realistic scenario to produce a model that accurately reflects the size and shape of the world, node count, movement patterns, and time period over which the MANET may operate. The animation technique has been used to develop a battlefield model based on established military tactics. Trace data has been used to build a model of maritime movements in the Irish Sea. Similar world models have been built using the random waypoint movement model for comparison. All models have been built using the ns-2 simulator. These models have been used to compare the performance of three routing protocols: dynamic source routing (DSR, destination-sequenced distance-vector routing (DSDV, and ad hoc n-demand distance vector routing (AODV. The findings reveal that protocol performance is dependent on the model used. In particular, it is shown that RWP models do not reflect the performance of these protocols under realistic circumstances, and protocol selection is subject to the scenario to which it is applied. To