1. |
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2. |
- Senanayake, Indunil C., et al.
(author)
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Fungal diversity notes 1611–1716: taxonomic and phylogenetic contributions on fungal genera and species emphasis in south China
- 2023
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In: Fungal Diversity. - 1560-2745 .- 1878-9129. ; 122, s. 161-403
-
Journal article (peer-reviewed)abstract
- This article is the 15th contribution in the Fungal Diversity Notes series, wherein 115 taxa from three phyla, nine classes, 28 orders, 48 families, and 64 genera are treated. Fungal taxa described and illustrated in the present study include a new family, five new genera, 61 new species, five new combinations, one synonym, one new variety and 31 records on new hosts or new geographical distributions. Ageratinicolaceae fam. nov. is introduced and accommodated in Pleosporales. The new genera introduced in this study are Ageratinicola, Kevinia, Pseudomultiseptospora (Parabambusicolaceae), Marasmiellomycena, and Vizzinia (Porotheleaceae). Newly described species are Abrothallus altoandinus, Ageratinicola kunmingensis, Allocryptovalsa aceris, Allophoma yuccae, Apiospora cannae, A. elliptica, A. pallidesporae, Boeremia wisteriae, Calycina papaeana, Clypeococcum lichenostigmoides, Coniochaeta riskali-shoyakubovii, Cryphonectria kunmingensis, Diaporthe angustiapiculata, D. campylandrae, D. longipapillata, Diatrypella guangdongense, Dothiorella franceschinii, Endocalyx phoenicis, Epicoccum terminosporum, Fulvifomes karaiensis, F. pannaensis, Ganoderma ghatensis, Hysterobrevium baoshanense, Inocybe avellaneorosea, I. lucida, Jahnula oblonga, Kevinia lignicola, Kirschsteiniothelia guangdongensis, Laboulbenia caprina, L. clavulata, L. cobiae, L. cosmodisci, L. nilotica, L. omalii, L. robusta, L. similis, L. stigmatophora, Laccaria rubriporus, Lasiodiplodia morindae, Lyophyllum agnijum, Marasmiellomycena pseudoomphaliiformis, Melomastia beihaiensis, Nemania guangdongensis, Nigrograna thailandica, Nigrospora ficuum, Oxydothis chinensis, O. yunnanensis, Petriella thailandica, Phaeoacremonium chinensis, Phialocephala chinensis, Phytophthora debattistii, Polyplosphaeria nigrospora, Pronectria loweniae, Seriascoma acutispora, Setoseptoria bambusae, Stictis anomianthi, Tarzetta tibetensis, Tarzetta urceolata, Tetraploa obpyriformis, Trichoglossum beninense, and Tricoderma pyrrosiae. We provide an emendation for Urnula ailaoshanensis Agaricus duplocingulatoides var. brevisporus introduced as a new variety based on morphology and phylogeny.
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3. |
- Beal, Jacob, et al.
(author)
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Robust estimation of bacterial cell count from optical density
- 2020
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Journal article (peer-reviewed)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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4. |
- Felsberg, Michael, et al.
(author)
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The Thermal Infrared Visual Object Tracking VOT-TIR2015 Challenge Results
- 2015
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In: Proceedings of the IEEE International Conference on Computer Vision. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781467383905 ; , s. 639-651
-
Conference paper (peer-reviewed)abstract
- The Thermal Infrared Visual Object Tracking challenge 2015, VOTTIR2015, aims at comparing short-term single-object visual trackers that work on thermal infrared (TIR) sequences and do not apply prelearned models of object appearance. VOT-TIR2015 is the first benchmark on short-term tracking in TIR sequences. Results of 24 trackers are presented. For each participating tracker, a short description is provided in the appendix. The VOT-TIR2015 challenge is based on the VOT2013 challenge, but introduces the following novelties: (i) the newly collected LTIR (Linköping TIR) dataset is used, (ii) the VOT2013 attributes are adapted to TIR data, (iii) the evaluation is performed using insights gained during VOT2013 and VOT2014 and is similar to VOT2015.
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5. |
- Felsberg, Michael, 1974-, et al.
(author)
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The Thermal Infrared Visual Object Tracking VOT-TIR2016 Challenge Results
- 2016
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In: Computer Vision – ECCV 2016 Workshops. ECCV 2016.. - Cham : SPRINGER INT PUBLISHING AG. - 9783319488813 - 9783319488806 ; , s. 824-849
-
Conference paper (peer-reviewed)abstract
- The Thermal Infrared Visual Object Tracking challenge 2016, VOT-TIR2016, aims at comparing short-term single-object visual trackers that work on thermal infrared (TIR) sequences and do not apply pre-learned models of object appearance. VOT-TIR2016 is the second benchmark on short-term tracking in TIR sequences. Results of 24 trackers are presented. For each participating tracker, a short description is provided in the appendix. The VOT-TIR2016 challenge is similar to the 2015 challenge, the main difference is the introduction of new, more difficult sequences into the dataset. Furthermore, VOT-TIR2016 evaluation adopted the improvements regarding overlap calculation in VOT2016. Compared to VOT-TIR2015, a significant general improvement of results has been observed, which partly compensate for the more difficult sequences. The dataset, the evaluation kit, as well as the results are publicly available at the challenge website.
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6. |
- Kristan, Matej, et al.
(author)
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The Visual Object Tracking VOT2015 challenge results
- 2015
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In: Proceedings 2015 IEEE International Conference on Computer Vision Workshops ICCVW 2015. - : IEEE. - 9780769557205 ; , s. 564-586
-
Conference paper (peer-reviewed)abstract
- The Visual Object Tracking challenge 2015, VOT2015, aims at comparing short-term single-object visual trackers that do not apply pre-learned models of object appearance. Results of 62 trackers are presented. The number of tested trackers makes VOT 2015 the largest benchmark on short-term tracking to date. For each participating tracker, a short description is provided in the appendix. Features of the VOT2015 challenge that go beyond its VOT2014 predecessor are: (i) a new VOT2015 dataset twice as large as in VOT2014 with full annotation of targets by rotated bounding boxes and per-frame attribute, (ii) extensions of the VOT2014 evaluation methodology by introduction of a new performance measure. The dataset, the evaluation kit as well as the results are publicly available at the challenge website(1).
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7. |
- Kristan, Matej, et al.
(author)
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The Visual Object Tracking VOT2016 Challenge Results
- 2016
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In: COMPUTER VISION - ECCV 2016 WORKSHOPS, PT II. - Cham : SPRINGER INT PUBLISHING AG. - 9783319488813 - 9783319488806 ; , s. 777-823
-
Conference paper (peer-reviewed)abstract
- The Visual Object Tracking challenge VOT2016 aims at comparing short-term single-object visual trackers that do not apply pre-learned models of object appearance. Results of 70 trackers are presented, with a large number of trackers being published at major computer vision conferences and journals in the recent years. The number of tested state-of-the-art trackers makes the VOT 2016 the largest and most challenging benchmark on short-term tracking to date. For each participating tracker, a short description is provided in the Appendix. The VOT2016 goes beyond its predecessors by (i) introducing a new semi-automatic ground truth bounding box annotation methodology and (ii) extending the evaluation system with the no-reset experiment.
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8. |
- Kristan, Matej, et al.
(author)
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The Visual Object Tracking VOT2017 challenge results
- 2017
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In: 2017 IEEE INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW 2017). - : IEEE. - 9781538610343 ; , s. 1949-1972
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Conference paper (peer-reviewed)abstract
- The Visual Object Tracking challenge VOT2017 is the fifth annual tracker benchmarking activity organized by the VOT initiative. Results of 51 trackers are presented; many are state-of-the-art published at major computer vision conferences or journals in recent years. The evaluation included the standard VOT and other popular methodologies and a new "real-time" experiment simulating a situation where a tracker processes images as if provided by a continuously running sensor. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The VOT2017 goes beyond its predecessors by (i) improving the VOT public dataset and introducing a separate VOT2017 sequestered dataset, (ii) introducing a realtime tracking experiment and (iii) releasing a redesigned toolkit that supports complex experiments. The dataset, the evaluation kit and the results are publicly available at the challenge website(1).
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9. |
- Kristanl, Matej, et al.
(author)
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The Seventh Visual Object Tracking VOT2019 Challenge Results
- 2019
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In: 2019 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW). - : IEEE COMPUTER SOC. - 9781728150239 ; , s. 2206-2241
-
Conference paper (peer-reviewed)abstract
- The Visual Object Tracking challenge VOT2019 is the seventh annual tracker benchmarking activity organized by the VOT initiative. Results of 81 trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in the recent years. The evaluation included the standard VOT and other popular methodologies for short-term tracking analysis as well as the standard VOT methodology for long-term tracking analysis. The VOT2019 challenge was composed of five challenges focusing on different tracking domains: (i) VOT-ST2019 challenge focused on short-term tracking in RGB, (ii) VOT-RT2019 challenge focused on "real-time" short-term tracking in RGB, (iii) VOT-LT2019 focused on long-term tracking namely coping with target disappearance and reappearance. Two new challenges have been introduced: (iv) VOT-RGBT2019 challenge focused on short-term tracking in RGB and thermal imagery and (v) VOT-RGBD2019 challenge focused on long-term tracking in RGB and depth imagery. The VOT-ST2019, VOT-RT2019 and VOT-LT2019 datasets were refreshed while new datasets were introduced for VOT-RGBT2019 and VOT-RGBD2019. The VOT toolkit has been updated to support both standard short-term, long-term tracking and tracking with multi-channel imagery. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The dataset, the evaluation kit and the results are publicly available at the challenge website(1).
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10. |
- Lai, Kuei-Hung, et al.
(author)
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Antileukemic Scalarane Sesterterpenoids and Meroditerpenoid from Carteriospongia (Phyllospongia) sp., Induce Apoptosis via Dual Inhibitory Effects on Topoisomerase II and Hsp90
- 2016
-
In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
-
Journal article (peer-reviewed)abstract
- Two new scalarane sesterterpenoids, 12 beta-(3'beta-hydroxybutanoyloxy)-20,24-dimethyl-24-oxo-scalara-16-en-25-al (1) and 12 beta-(3'beta-hydroxypentanoyloxy)-20,24-dimethyl-24-oxo-scalara-16-en-25-al (2), along with one known tetraprenyltoluquinol-related metabolite (3), were isolated from the sponge Carteriospongia sp. In leukemia Molt 4 cells, 1 at 0.0625 mu g/mL (125 nM) triggered mitochondrial membrane potential (MMP) disruption and apoptosis showing more potent effect than 2 and 3. The isolates inhibited topoisomerase II alpha expression. The apoptotic-inducing effect of 3 was supported by the in vivo experiment through suppressing the volume of xenograft tumor growth (47.58%) compared with the control. Compound 1 apoptotic mechanism of action in Molt 4 cells was further elucidated through inducing ROS generation, calcium release and ER stress. Using the molecular docking analysis, 1 exhibited more binding affinity to N-terminal ATP-binding pocket of Hsp90 protein than 17-AAG, a standard Hsp90 inhibitor. The expression of Hsp90 client proteins, Akt, p70(S6k), NF kappa B, Raf-1, p-GSK3 beta, and XIAP, MDM 2 and Rb2, and CDK4 and Cyclin D3, HIF1 and HSF1 were suppressed by the use of 1. However, the expression of Hsp70, acetylated tubulin, and activated caspase 3 were induced after 1 treatment. Our results suggested that the proapoptotic effect of the isolates is mediated through the inhibition of Hsp90 and topoisomerase activities.
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11. |
- Aad, G, et al.
(author)
-
- 2015
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swepub:Mat__t
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12. |
- Abd El-Wahed, Aida, et al.
(author)
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Wasp Venom Biochemical Components and Their Potential in Biological Applications and Nanotechnological Interventions
- 2021
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In: Toxins. - : MDPI AG. - 2072-6651. ; 13:3
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Research review (peer-reviewed)abstract
- Wasps, members of the order Hymenoptera, are distributed in different parts of the world, including Brazil, Thailand, Japan, Korea, and Argentina. The lifestyles of the wasps are solitary and social. Social wasps use venom as a defensive measure to protect their colonies, whereas solitary wasps use their venom to capture prey. Chemically, wasp venom possesses a wide variety of enzymes, proteins, peptides, volatile compounds, and bioactive constituents, which include phospholipase A2, antigen 5, mastoparan, and decoralin. The bioactive constituents have anticancer, antimicrobial, and anti-inflammatory effects. However, the limited quantities of wasp venom and the scarcity of advanced strategies for the synthesis of wasp venom’s bioactive compounds remain a challenge facing the effective usage of wasp venom. Solid-phase peptide synthesis is currently used to prepare wasp venom peptides and their analogs such as mastoparan, anoplin, decoralin, polybia-CP, and polydim-I. The goal of the current review is to highlight the medicinal value of the wasp venom compounds, as well as limitations and possibilities. Wasp venom could be a potential and novel natural source to develop innovative pharmaceuticals and new agents for drug discovery.
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13. |
- Cheng, Ran, et al.
(author)
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In Vitro and in Vivo Evaluation of C-11-Labeled Azetidinecarboxylates for Imaging Monoacylglycerol Lipase by PET Imaging Studies
- 2018
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In: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 61:6, s. 2278-2291
-
Journal article (peer-reviewed)abstract
- Monoacylglycerol lipase (MAGL) is the principle enzyme for metabolizing endogenous cannabinoid ligand 2-arachidonoyglycerol (2-AG). Blockade of MAGL increases 2-AG levels, resulting in subsequent activation of the endocannabinoid system, and has emerged as a novel therapeutic strategy to treat drug addiction, inflammation, and neurodegenerative diseases. Herein we report a new series of MAGL inhibitors, which were radiolabeled by site-specific labeling technologies, including C-11-carbonylation and spirocyclic iodonium ylide (SCIDY) radio fluorination. The lead compound [C-11]10 (MAGL-0519) demonstrated high specific binding and selectivity in vitro and in vivo. We also observed unexpected washout kinetics with these irreversible radiotracers, in which in vivo evidence for turnover of the covalent residue was unveiled between MAGL and azetidine carboxylates. This work may lead to new directions for drug discovery and PET tracer development based on azetidine carboxylate inhibitor scaffold.
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14. |
- Cheng, Shuzhen, et al.
(author)
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Crassostrea gigas-Based Bioactive Peptide Protected Thrombin-Treated Endothelial Cells against Thrombosis and Cell Barrier Dysfunction
- 2022
-
In: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 70:31, s. 9664-9673
-
Journal article (peer-reviewed)abstract
- The activation of thrombin-treated endothelial cells resulted in disruption of the vascular tissues. A novel oyster-derived bioactive dodecapeptide (IEELEELEAER, P-2-CG) was reported to protect the human umbilical vein endothelial cells and their barrier function via the decrease of VE-cadherin disruption and the restoration of the F-actin arrangement. The promotion of the extrinsic pathway in this case triggers the release of tissue factors that occurs on the surface of the endothelial cells, thus changing the antithrombotic to prothrombotic. P-2-CG induced accordingly a prolongation of plasma clotting time and thrombin generation time, following the alteration of the antithrombotic phenotype. Furthermore, the antithrombotic activity of P-2-CG was also supported by the reduction of FXa and the inhibition of other factors release, for instance, inflammation factors, ROS, etc. In addition to its antithrombogenic role, P-2-CG displayed anti-inflammatory and antioxidant properties via the mitogen-activated protein kinase cascades and central signaling pathways as shown in an in vitro model of endothelial dysfunction.
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15. |
- Danaei, Goodarz, et al.
(author)
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Effects of diabetes definition on global surveillance of diabetes prevalence and diagnosis: a pooled analysis of 96 population-based studies with 331288 participants
- 2015
-
In: The Lancet Diabetes & Endocrinology. - 2213-8595 .- 2213-8587. ; 3:8, s. 624-637
-
Journal article (peer-reviewed)abstract
- Background Diabetes has been defined on the basis of different biomarkers, including fasting plasma glucose (FPG), 2-h plasma glucose in an oral glucose tolerance test (2hOGTT), and HbA(1c). We assessed the effect of different diagnostic definitions on both the population prevalence of diabetes and the classification of previously undiagnosed individuals as having diabetes versus not having diabetes in a pooled analysis of data from population-based health examination surveys in different regions. Methods We used data from 96 population-based health examination surveys that had measured at least two of the biomarkers used for defining diabetes. Diabetes was defined using HbA(1c) (HbA(1c) >= 6 . 5% or history of diabetes diagnosis or using insulin or oral hypoglycaemic drugs) compared with either FPG only or FPG-or-2hOGTT definitions (FPG >= 7 . 0 mmol/L or 2hOGTT >= 11 . 1 mmol/L or history of diabetes or using insulin or oral hypoglycaemic drugs). We calculated diabetes prevalence, taking into account complex survey design and survey sample weights. We compared the prevalences of diabetes using different definitions graphically and by regression analyses. We calculated sensitivity and specificity of diabetes diagnosis based on HbA1c compared with diagnosis based on glucose among previously undiagnosed individuals (ie, excluding those with history of diabetes or using insulin or oral hypoglycaemic drugs). We calculated sensitivity and specificity in each survey, and then pooled results using a random-effects model. We assessed the sources of heterogeneity of sensitivity by meta-regressions for study characteristics selected a priori. Findings Population prevalence of diabetes based on FPG- or-2hOGTT was correlated with prevalence based on FPG alone (r= 0 . 98), but was higher by 2-6 percentage points at different prevalence levels. Prevalence based on HbA(1c) was lower than prevalence based on FPG in 42 . 8% of age-sex-survey groups and higher in another 41 . 6%; in the other 15 . 6%, the two definitions provided similar prevalence estimates. The variation across studies in the relation between glucose-based and HbA(1c)-based prevalences was partly related to participants' age, followed by natural logarithm of per person gross domestic product, the year of survey, mean BMI, and whether the survey population was national, subnational, or from specific communities. Diabetes defined as HbA(1c) 6 . 5% or more had a pooled sensitivity of 52 . 8% (95% CI 51 . 3-54 . 3%) and a pooled specificity of 99 . 74% (99 . 71-99 . 78%) compared with FPG 7 . 0 mmol/L or more for diagnosing previously undiagnosed participants; sensitivity compared with diabetes defined based on FPG-or-2hOGTT was 30 . 5% (28 . 7-32 . 3%). None of the preselected study-level characteristics explained the heterogeneity in the sensitivity of HbA(1c) versus FPG. Interpretation Different biomarkers and definitions for diabetes can provide different estimates of population prevalence of diabetes, and differentially identify people without previous diagnosis as having diabetes. Using an HbA(1c)-based definition alone in health surveys will not identify a substantial proportion of previously undiagnosed people who would be considered as having diabetes using a glucose-based test.
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16. |
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17. |
- Du, Jinfeng, et al.
(author)
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Capacity Bounds for Backhaul-Supported Wireless Multicast Relay Networks with Cross-Links
- 2011
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In: IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC), 2011. - NEW YORK : IEEE conference proceedings. - 9781612842325 - 9781612842318 ; , s. 1-5
-
Conference paper (peer-reviewed)abstract
- We investigate the capacity bounds for a wireless multicast relay network where two sources simultaneously multicast to two destinations through Gaussian channels with the help of a full-duplex relay node. All the individual channel gains are assumed to be time-invariant and known to every nodes in the network. The transmissions from two sources and from the relay use the same channel resource (i.e. co-channel transmission) and the two source nodes are connected with an orthogonal error-free backhaul. This multicast relay network is generic in the sense that it can be extended to more general networks by tuning the channel gains within the range [0, ∞). By extending the proof of the converse developed by Cover and El Gamal for the Gaussian relay channel, we characterize the cut-set bound for this multicast relay network. We also present a lower bound by using decoding-and-forward relaying combined with network beam-forming.
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18. |
- Du, Jinfeng, et al.
(author)
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Capacity bounds for relay-aided wireless multiple multicast with backhaul
- 2010
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In: 2010 International Conference on Wireless Communications and Signal Processing, WCSP 2010. - NEW YORK : IEEE conference proceedings. - 9781424475568 - 9781424475544 ; , s. 1-5
-
Conference paper (peer-reviewed)abstract
- We investigate the capacity bounds for relay-aided two-source two-destination wireless networks with backhaul support between source nodes. Each source multicasts its own message to all destinations with the help of an intermediate relay node, which is full-duplex and shared by both sources. We are aiming to characterize the capacity region of this model given discrete memoryless Gaussian channels. We establish three capacity upper bounds by relaxing the cut-set bound, and by extending two capacity bounds originally derived for MIMO relay channels. We also present one lower bound by using decoding-and-forward relaying combined with network beam-forming.
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19. |
- Du, Jinfeng, et al.
(author)
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Cooperative Network Coding Strategies for Wireless Relay Networks with Backhaul
- 2011
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In: IEEE Transactions on Communications. - 0090-6778 .- 1558-0857. ; 59:9, s. 2502-2514
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Journal article (peer-reviewed)abstract
- We investigate cooperative network coding strategies for relay-aided two-source two-destination wireless networks with a backhaul connection between the source nodes. Each source multicasts information to all destinations using a shared relay. We study cooperative strategies based on different network coding schemes, namely, finite field and linear network coding, and lattice coding. To further exploit the backhaul connection, we also propose network coding based beamforming. We measure the performance in term of achievable rates over Gaussian channels, and observe significant gains over benchmark schemes. We derive the achievable rate regions for these schemes and find the cut-set bound for our system. We also show that the cut-set bound can be achieved by network coding based beamforming when the signal-to-noise ratios lie in the sphere defined by the source-relay and relay-destination channel gains.
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20. |
- Du, Jinfeng, et al.
(author)
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Cooperative strategies for relay-aided multi-cell wireless networks with backhaul
- 2010
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In: 2010 IEEE Information Theory Workshop, ITW 2010 - Proceedings. - NEW YORK : IEEE conference proceedings. - 9781424482627 - 9781424482634 ; , s. 1-5
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Conference paper (peer-reviewed)abstract
- We investigate cooperative strategies for relay-aided multi-source multi-destination wireless networks with backhaul support. Each source multicasts information to all destinations using a shared relay. We study cooperative strategies based on different network coding (NC) schemes, namely, finite field NC (FNC), linear NC (LNC), and lattice coding. To further exploit the backhaul connection, we also propose NC-based beam-forming (NBF). We measure the performance in term of achievable rates over Gaussian channels and observe significant gains over a benchmark scheme. The benefit of using backhaul is also clearly demonstrated in most of scenarios.
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21. |
- Du, Jinfeng
(author)
-
Cooperative Strategies in Multi-Terminal Wireless Relay Networks
- 2012
-
Doctoral thesis (other academic/artistic)abstract
- Smart phones and tablet computers have greatly boosted the demand for services via wireless access points, keeping constant pressure on the network providers to deliver vast amounts of data over the wireless infrastructure. To enlarge coverage and enhance throughput, relaying has been adopted in the new generation of wireless communication systems, such as in the Long-Term Evolution Advanced standard, and will continue to play an important role in the next generation wireless infrastructure. Depending on functionality, relaying can be characterizing into three main categories: amplify-and-forward (AF), compression-and-forward (CF), and decode-and-forward (DF). In this thesis, we investigate different cooperative strategies in wireless networks when relaying is in use.We first investigate the capacity outer and inner bounds for a wireless multicast relay network where two sources, connected by error-free backhaul, multicast to two destinations with the help of a full-duplex relay node. For high-rate backhaul scenarios, we find the exact cut-set bound of the capacity region by extending the proof of the converse for the Gaussian relay channel. For low-rate backhaul scenarios, we present two genie-aided outer bounds by extending the previous proof and introducing two lemmas on conditional (co-)variance. Our inner bounds are derived from various cooperative strategies by combining DF/CF/AF relaying with network coding schemes. We also extend the noisy network coding scheme and the short-message noisy network coding approach to correlated sources. For low-rate backhaul, we propose a new coding scheme, partial-decode-and-forward based linear network coding. We derive the achievable rate regions for these schemes and measure the performance in term of achievable rates over Gaussian channels. By numerical investigation we observe significant gains over benchmark schemes and demonstrate that the gap between upper and lower bounds is in general not large. We also show that for high-rate backhaul, the cut-set bound can be achieved when the signal-to-noise ratios lie in the sphere defined by the source-relay and relay-destination channel gains.For wireless networks with independent noise, we propose a simple framework to get capacity outer and inner bounds based on the ``one-shot'' bounding models. We first extend the models for two-user broadcast channels to many-user scenarios and then establish the gap between upper and lower bounding models. For networks with coupled links, we propose a channel decoupling method which can decompose the network into overlapping multiple-access channels and broadcast channels. We then apply the one-shot models and create an upper bounding network with only bit-pipe connections. When developing the lower bounding network, we propose a two-step update of these models for each coupled broadcast and multiple-access channels. We demonstrate by some examples that the resulting upper bound is in general very good and the gap between the upper and lower bounds is usually not large.For relay-aided downlink scenarios, we propose a cooperation scheme by cancelling interference at the transmitter. It is indeed a symbol-by-symbol approach to one-dimension dirty paper coding (DPC). For finite-alphabet signaling and interference, we derive the optimal (in terms of maximum mutual information) modulator under a given power constraint. A sub-optimal modulator is also proposed by formulating an optimization problem that maximizes the minimum distance of the signal constellation, and this non-convex optimization problem is approximately solved by semi-definite relaxation. Bit-level simulation shows that the optimal and sub-optimal modulators can achieve significant gains over the Tomlinson-Harashima precoder (THP) benchmark and over non-DPC reference schemes, especially when the power of the interference is larger than the power of the noise.
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22. |
- Du, Jinfeng, et al.
(author)
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Lower bounding models for wireless networks
- 2013
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In: Proceedings of IEEE International Symposium on Information Theory, 2013. - : IEEE conference proceedings. ; , s. 1456-1460
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Conference paper (peer-reviewed)abstract
- Motivated by the framework of network equivalencetheory [1], [2], we present capacity lower bounding models forwireless networks by construction of noiseless networks whichcan be used to calculate an inner bound for the correspondingwireless network. We first extend the “one-shot” lower boundingmodel [6] to many-user scenarios, and then propose a two-stepupdate of the one-shot models to incorporate the broadcast natureof wireless transmission. The main advantage of the proposedlower bounding method is its simplicity and the fact that it can beeasily extended to larger networks. We demonstrate by examplesthat the resulting lower bounds can even approach the capacityin some setups.
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23. |
- Du, Jinfeng, et al.
(author)
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Optimal Symbol-by-Symbol Costa Precoding for a Relay-aided Downlink Channel
- 2011
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In: IEEE Transactions on Communications. - : IEEE. - 0090-6778 .- 1558-0857. ; 59:8, s. 2274-2284
-
Journal article (peer-reviewed)abstract
- In this article, we consider practical approaches to Costa precoding (also known as dirty paper coding). Specifically, we propose a symbol-by-symbol scheme for cancellation of interference known at the transmitter in a relay-aided downlink channel. For finite-alphabet signaling and interference, we derive the optimal (in terms of maximum mutual information) modulator under a given power constraint. A sub-optimal modulator is also proposed by formulating an optimization problem that maximizes the minimum distance of the signal constellation, and this non-convex optimization problem is approximately solved by semi-definite relaxation. For the case of binary signaling with binary interference, we obtain a closed-form solution for the sub-optimal modulator, which only suffers little performance degradation compared to the optimal modulator in the region of interest. For more general signal constellations and more general interference distributions, we propose an optimized Tomlinson-Harashima precoder (THP), which uniformly outperforms conventional THP with heuristic parameters. Bit-level simulation shows that the optimal and sub-optimal modulators can achieve significant gains over the THP benchmark as well as over non-Costa reference schemes, especially when the power of the interference is larger than the power of the noise.
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24. |
- Du, Jinfeng, et al.
(author)
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Scalable Capacity Bounding Models for Wireless Networks
- 2016
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In: IEEE Transactions on Information Theory. - : IEEE Press. - 0018-9448 .- 1557-9654. ; 62:1, s. 208-229
-
Journal article (peer-reviewed)abstract
- The framework of network equivalence theory developed by Koetter et al. introduces a notion of channel emulation to construct noiseless networks as upper (respectively, lower) bounding models, which can be used to calculate the outer (respectively, inner) bounds for the capacity region of the original noisy network. Based on the network equivalence framework, this paper presents scalable upper and lower bounding models for wireless networks with potentially many nodes. A channel decoupling method is proposed to decompose wireless networks into decoupled multiple-access channels and broadcast channels. The upper bounding model, consisting of only point-to-point bit pipes, is constructed by first extending the one-shot upper bounding models developed by Calmon et al. and then integrating them with network equivalence tools. The lower bounding model, consisting of both point-to-point and point-to-points bit pipes, is constructed based on a two-step update of the lower bounding models to incorporate the broadcast nature of wireless transmission. The main advantages of the proposed methods are their simplicity and the fact that they can be extended easily to large networks with a complexity that grows linearly with the number of nodes. It is demonstrated that the resulting upper and lower bounds can approach the capacity in some setups.
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25. |
- Du, Jinfeng, et al.
(author)
-
Scalable capacity bounding models for wireless networks
-
Other publication (other academic/artistic)abstract
- Based on the framework of network equivalence theory developed by Koetter et al., this paper presents scalable capacity upper and lower bounding models for wireless networks by construction of noiseless networks that can be used to calculate outer and inner bounds, respectively, for the original networks. A channel decoupling method is proposed to decompose wireless networks into point-to-point channels, and (potentially) coupled multiple-access channels (MACs) and broadcast channels (BCs). The upper bounding model, consisting of only point-to-point bit-pipes, is constructed by firstly extending the "one-shot" bounding models developed by Calmon et al. and then integrating them with network equivalence tools. The lower bounding model, consisting of both point-to-point and point-to-points bit-pipes, is constructed based on a two-step update of the one-shot models to incorporate the broadcast nature of wireless transmission. The main advantages of the proposed methods are their simplicity and the fact that they can be extended easily to large networks with a complexity that grows linearly with the number of nodes. It is demonstrated that the gap between the resulting upper and lower bounds is usually not large, and they can approach the capacity in some setups.
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26. |
- Du, Jinfeng, et al.
(author)
-
Scalable upper bounding models for wireless networks
- 2014
-
In: Proceedings of IEEE International Symposium on Information Theory. - : IEEE conference proceedings. ; , s. 241-245
-
Conference paper (peer-reviewed)abstract
- The framework of network equivalence theory developed by Koetter et al. introduces a notion of channel emulation to construct noiseless networks as upper/lower bounding models for the original noisy network. This paper presents scalable upper bounding models for wireless networks, by firstly extending the ``one-shot'' bounding models developed by Calmon et al. and then integrating them with network equivalence tools. A channel decoupling method is proposed to decompose wireless networks into decoupled multiple-access channels (MACs) and broadcast channels (BCs). The main advantages of the proposed method is its simplicity and the fact that it can be extended easily to large networks with a complexity that grows linearly with the number of nodes. It is demonstrated that the resulting upper bounds can approach the capacity in some setups.
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27. |
- Du, Jinfeng, et al.
(author)
-
Short-Message Noisy Network Coding with Partial Source Cooperation
- 2012
-
In: Information Theory Workshop (ITW), 2012 IEEE. - : IEEE conference proceedings. - 9781467302234 ; , s. 144-147
-
Conference paper (peer-reviewed)abstract
- Noisy network coding (NNC) has been shown to outperform standard compress-and-forward (CF) in networks with multiple relays and/or multiple destinations. Recently, short-message noisy network coding (SNNC) has been proved to achieve the same rate region as NNC for independent sources but with significantly reduced encoding delay and decoding complexity. In this paper, we show that when partial cooperation between source nodes is possible, by performing rate-splitting, message exchange, and superposition coding with proper power allocation at the source nodes, SNNC can achieve a strictly larger rate region than NNC. The gain comes from coherent combining at all the receiving nodes.
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28. |
- Du, Jinfeng, et al.
(author)
-
Wireless multicast relay networks with limited-rate source-conferencing
- 2013
-
In: IEEE Journal on Selected Areas in Communications. - : IEEE Press. - 0733-8716 .- 1558-0008. ; 31:8, s. 1390-1401
-
Journal article (peer-reviewed)abstract
- We investigate capacity bounds for a wireless multicast relay network where two sources simultaneously multicast to two destinations with the help of a full-duplex relay node. The two sources and the relay use the same channel resources (i.e. co-channel transmission). We assume Gaussian channels with time-invariant channel gains which are known by all nodes. The two source nodes are connected by orthogonal limited-rate error-free conferencing links. By extending the proof of the converse for the Gaussian relay channel and introducing two lemmas on conditional (co-)variance, we present two genie-aided outer bounds of the capacity region for this multicast relay network. We extend noisy network coding to use source cooperation with the help of the theory of network equivalence. We also propose a new coding scheme, partial-decode-and- forward based linear network coding, which is essentially a hybrid scheme utilizing rate-splitting and messages conferencing at the source nodes, partial decoding and linear network coding at the relay, and joint decoding at each destination. A low-complexity alternative scheme, analog network coding based on amplify-and-forward relaying, is also investigated and shown to benefit greatly from the help of the conferencing links and can even outperform noisy network coding when the coherent combining gain is dominant.
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29. |
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30. |
- Du, Rong, 1989-, et al.
(author)
-
Energy efficient monitoring of water distribution networks via compressive sensing
- 2015
-
In: 2015 IEEE International Conference on Communications (ICC). - : IEEE conference proceedings. - 9781467364324 ; , s. 6681-6686
-
Conference paper (peer-reviewed)abstract
- The recent development of low cost wireless sensors enables water monitoring through dense wireless sensor networks (WSN). Sensor nodes are battery powered devices, and hence their limited energy resources have to be optimally managed. The latest advancements in compressive sensing (CS) provide ample promise to increase WSNs lifetime by limiting the amount of measurements that have to be collected. Additional energy savings can be achieved through CS-based scheduling schemes that activate only a limited number of sensors to sense and transmit their measurements, whereas the rest are turned off. The ultimate objective is to maximize network lifetime without sacrificing network connectivity and monitoring performance. This problem can be approximated by an energy balancing approach that consists of multiple simpler subproblems, each of which corresponds to a specific time period. Then, the sensors that should be activated within a given period can be optimally derived through dynamic programming. The complexity of the proposed CS-based scheduling scheme is characterized and numerical evaluation reveals that it achieves comparable monitoring performance by activating only a fraction of the sensors.
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31. |
- Du, Rong, et al.
(author)
-
Energy Efficient Sensor Activation for Water Distribution Networks Based on Compressive Sensing
- 2015
-
In: IEEE Journal on Selected Areas in Communications. - : IEEE. - 0733-8716 .- 1558-0008. ; 33:12, s. 2997-3010
-
Journal article (peer-reviewed)abstract
- The recent development of low cost wireless sensors enables novel internet-of-things (IoT) applications, such as the monitoring of water distribution networks. In such scenarios, the lifetime of the wireless sensor network (WSN) is a major concern, given that sensor node replacement is generally inconvenient and costly. In this paper, a compressive sensing-based scheduling scheme is proposed that conserves energy by activating only a small subset of sensor nodes in each timeslot to sense and transmit. Compressive sensing introduces a cardinality constraint that makes the scheduling optimization problem particularly challenging. Taking advantage of the network topology imposed by the IoT water monitoring scenario, the scheduling problem is decomposed into simpler subproblems, and a dynamic-programming-based solution method is proposed. Based on the proposed method, a solution algorithm is derived, whose complexity and energy-wise performance are investigated. The complexity of the proposed algorithm is characterized and its performance is evaluated numerically via an IoT emulator of water distribution networks. The analytical and numerical results show that the proposed algorithm outperforms state-of-the-art approaches in terms of energy consumption, network lifetime, and robustness to sensor node failures. It is argued that the derived solution approach is general and it can be potentially applied to more IoT scenarios such as WSN scheduling in smart cities and intelligent transport systems.
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32. |
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33. |
- Du, Rong, et al.
(author)
-
Joint node deployment and wireless energy transfer scheduling for immortal sensor networks
- 2017
-
In: 2017 15th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks, WiOpt 2017. - : Institute of Electrical and Electronics Engineers (IEEE). - 9783901882906
-
Conference paper (peer-reviewed)abstract
- The lifetime of a wireless sensor network (WSN) is limited by the lifetime of the individual sensor nodes. A promising technique to extend the lifetime of the nodes is wireless energy transfer. The WSN lifetime can also be extended by exploiting the redundancy in the nodes' deployment, which allows the implementation of duty-cycling mechanisms. In this paper, the joint problem of optimal sensor node deployment and WET scheduling is investigated. Such a problem is formulated as an integer optimization whose solution is challenging due to the binary decision variables and non-linear constraints. To solve the problem, an approach based on two steps is proposed. First, the necessary condition for which the WSN is immortal is established. Based on this result, an algorithm to solve the node deployment problem is developed. Then, the optimal WET scheduling is given by a scheduling algorithm. The WSN is shown to be immortal from a networking point of view, given the optimal deployment and WET scheduling. Theoretical results show that the proposed algorithm achieves the optimal node deployment in terms of the number of deployed nodes. In the simulation, it is shown that the proposed algorithm reduces significantly the number of nodes to deploy compared to a random-based approach. The results also suggest that, under such deployment, the optimal scheduling and WET can make WSNs immortal.
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34. |
- Du, Rong, et al.
(author)
-
Lifetime Maximization for Sensor Networks with Wireless Energy Transfer
- 2016
-
In: 2016 IEEE International Conference on Communications, ICC 2016. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781479966646 ; , s. 20-25
-
Conference paper (peer-reviewed)abstract
- In Wireless Sensor Networks (WSNs), to supply energy to the sensor nodes, wireless energy transfer (WET) is a promising technique. One of the most efficient procedures to transfer energy to the sensor nodes consists in using a sharp wireless energy beam from the base station to each node at a time. A natural fundamental question is what is the lifetime ensured by WET and how to maximize the network lifetime by scheduling the transmissions of the energy beams. In this paper, such a question is addressed by posing a new lifetime maximization problem for WET enabled WSNs. The binary nature of the energy transmission process introduces a binary constraint in the optimization problem, which makes challenging the investigation of the fundamental properties of WET and the computation of the optimal solution. The sufficient condition for which the WET makes WSNs immortal is established as function of the WET parameters. When such a condition is not met, a solution algorithm to the maximum lifetime problem is proposed. The numerical results show that the lifetime achieved by the proposed algorithm increases by about 50% compared to the case without WET, for a WSN with a small to medium size number of nodes. This suggests that it is desirable to schedule WET to prolong lifetime of WSNs having small or medium network sizes.
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35. |
- Du, Rong, et al.
(author)
-
On Maximizing Sensor Network Lifetime by Energy Balancing
- 2018
-
In: IEEE Transactions on Control of Network Systems. - : Institute of Electrical and Electronics Engineers (IEEE). - 2325-5870. ; 5:3
-
Journal article (peer-reviewed)abstract
- Many physical systems, such as water/electricity distribution networks, are monitored by battery-powered wireless-sensor networks (WSNs). Since battery replacement of sensor nodes is generally difficult, long-term monitoring can be only achieved if the operation of the WSN nodes contributes to long WSN lifetime. Two prominent techniques to long WSN lifetime are 1) optimal sensor activation and 2) efficient data gathering and forwarding based on compressive sensing. These techniques are feasible only if the activated sensor nodes establish a connected communication network (connectivity constraint), and satisfy a compressive sensing decoding constraint (cardinality constraint). These two constraints make the problem of maximizing network lifetime via sensor node activation and compressive sensing NP-hard. To overcome this difficulty, an alternative approach that iteratively solves energy balancing problems is proposed. However, understanding whether maximizing network lifetime and energy balancing problems are aligned objectives is a fundamental open issue. The analysis reveals that the two optimization problems give different solutions, but the difference between the lifetime achieved by the energy balancing approach and the maximum lifetime is small when the initial energy at sensor nodes is significantly larger than the energy consumed for a single transmission. The lifetime achieved by energy balancing is asymptotically optimal, and that the achievable network lifetime is at least 50% of the optimum. Analysis and numerical simulations quantify the efficiency of the proposed energy balancing approach.
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36. |
- Du, Rong, et al.
(author)
-
Optimal Energy Beamforming and Data Routing for Immortal Wireless Sensor Networks
- 2017
-
In: IEEE International Conference on Communications. - : Institute of Electrical and Electronics Engineers (IEEE). - 1550-3607. - 9781467389990
-
Conference paper (peer-reviewed)abstract
- Wireless sensor networks (WSNs) consist of energy limited sensor nodes, which limits the network lifetime. Such a lifetime can be prolonged by employing the emerging technology of wireless energy transfer (WET). In WET systems, the sensor nodes can harvest wireless energy from wireless charger, which can use energy beamforming to improve the efficiency. In this paper, a scenario where dedicated wireless chargers with multiple antennas use energy beamforming to charge sensor nodes is considered. The energy beamforming is coupled with the energy consumption of sensor nodes in terms of data routing, which is one novelty of the paper. The energy beamforming and the data routing are jointly optimized by a non-convex optimization problem. This problem is transformed into a semidefinite optimization problem, for which strong duality is proved, and thus the optimal solution exists. It is shown that the optimal solution of the semi-definite programming problem allows to derive the optimal solution of the original problem. The analytical and numerical results show that optimal energy beamforming gives two times better monitoring performance than that of WET without using energy beamforming.
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37. |
- Du, Rong, 1989-
(author)
-
Optimal Networking in Wirelessly Powered Sensor Networks
- 2018
-
Doctoral thesis (other academic/artistic)abstract
- Wireless sensor networks (WSNs) are nowadays widely used for the long-term monitoring of small or large regions, such as lakes, forests, cities, and industrial areas. The performance of a WSN typically consists of two aspects: i) the monitoring performance, e.g., the accuracy and the timeliness of the measurements or estimations produced by the sensor nodes of the WSN; and ii) the lifetime, i.e., how long the WSN can sustain such a performance. Naturally, we would like to have the monitoring performance as good as possible, and the lifetime as long as possible. However, in traditional WSNs, the sensor nodes generally have limited resources, especially in terms of battery capacity. If the nodes make measurements and report them frequently for a good monitoring performance, they drain their batteries and this leads to a severely shortened network lifetime. Conversely, the sensors can have a longer lifetime by sacrificing the monitoring performance. It shows the inherent trade-off between the monitoring performance and the lifetime in WSNs.We can overcome the limitations of the trade-off described above by wireless energy transfer (WET), where we can provide the sensor nodes with additional energy remotely. The WSNs with WET are called wirelessly powered sensor networks (WPSNs). In a WPSN, dedicated energy sources, e.g., static base stations or mobile chargers, transmit energy via radio frequency (RF) waves to the sensor nodes. The nodes can store the energy in their rechargeable batteries and use it later when it is needed. In so doing, they can use more energy to perform the sensing tasks. Thus, WET is a solution to improve the monitoring performance and lifetime at the same time. As long as the nodes receive more energy than they consume, it is possible that the WSN be immortal, which is impossible in traditional WSNs. Although WPSNs can potentially break the trade-off between monitoring performance and lifetime, they also bring many fundamental design and performance analysis challenges. Due to the safety issues, the power that the dedicated energy sources can use is limited. The propagation of the RF waves suffers high path losses. Therefore, the energy received by the sensor nodes is much less than the energy transmitted from the sources. As a result, to have a good WSN performance, we should optimize the energy transmission on the energy source side and the energy consumption on the nodes side. Compared to the traditional WSN scenarios where we can only optimize the sensing and data communication strategies, in WPSNs, we have an additional degree of freedom, i.e., the optimization of the energy transmission strategies. This aspect brings new technical challenges and problems that have not been studied in the traditional WSNs. Several novel research questions arise, such as when and how to transmit the energy, and which energy source should transmit. Such questions are not trivial especially when we jointly consider the energy consumption part.This thesis contributes to answer the questions above. It consists of three contributions as follows.In the first contribution, we consider a WPSN with single energy base stations (eBS) and multiple sensor nodes to monitor several separated areas of interest. The eBS has multiple antennas, and it uses energy beamforming to transmit energy to the nodes. Notice that, if we deploy multiple sensor nodes at the same area, these nodes may receive the energy from the eBS at the same time and they can reduce the energy consumption by applying sleep/awake mechanism. Therefore, we jointly study the deployment of the nodes, the energy transmission of the eBS, and the node activation. The problem is an integer optimization, and we decouple the problem into a node deployment problem and a scheduling problem. We provide a greedy-based algorithm to solve the problem, and show its performance in terms of optimality.The second contribution of the thesis starts by noticing that wireless channel state information (CSI) is important for energy beamforming. The more energy that an eBS spends in channel acquisition, the more accurate CSI it will have, thus improving the energy beamforming performance. However, if the eBS spends too much energy on channel acquisition, it will have less energy for WET, which might reduce the energy that is received by the sensor nodes. We thus investigate how much energy the eBS should spend in channel acquisition, i.e., we study the power allocation problem in channel acquisition and energy beamforming for WPSNs. We consider the general optimal channel acquisition and show that the problem is non-convex. Based on the idea of bisection search, we provide an algorithm to find the optimal solution for the single eBS cases, and a closed-form solution for the case where the eBS uses orthogonal pilot transmission, least-square channel estimation, and maximum ratio transmission for WET. The simulations show that the algorithm converges fast, and the performance is close to the theoretical upper bound.In the third contribution, we consider a joint energy beamforming and data routing problem for WPSNs. More specifically, we investigate the WPSNs consisting of multiple eBSs, multiple sensor nodes, and a sink node. Based on the received energy, the sensor nodes need to decide how to route their data. The problem aims at maximizing the minimum sensing rate of the sensor nodes while guaranteeing that the received energy of each node is no less than that is consumed. Such a problem is non-convex, and we provide a centralized solution algorithm based on a semi-definite programming transformation. We extend this approach with a distributed algorithm using alternating direction method of multipliers (ADMM). We prove that the centralized algorithm achieves the optimal energy beamforming and routing, and we show by simulation that the distributed one converges to the optimal solution. Additionally, for the cases where the energy beamforming options are pre-determined, we study the problem of finding the energy that should be spent on each vector. We observe that, if the pre-determined beamforming options are chosen wisely, their performance is close to the optimal.The results of the thesis show that WET can prolong the lifetime of WSNs, and even make them work sufficiently long for general monitoring applications. More importantly, we should optimize the WPSN by considering both the energy provision and the energy consumption part. The studies of the thesis have the potential to be used in many Internet of Things (IoT) systems in smart cities, such as water distribution lines and building monitoring.
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38. |
- Du, Rong, 1989-, et al.
(author)
-
Optimal Node Deployment and Energy Provision for Wirelessly Powered Sensor Networks
- 2018
-
In: IEEE Journal on Selected Areas in Communications. - : IEEE Press. - 0733-8716 .- 1558-0008. ; 37:2, s. 407-423
-
Journal article (peer-reviewed)abstract
- In a typical wirelessly powered sensor network (WPSN), wireless chargers provide energy to sensor nodes by using wireless energy transfer (WET). The chargers can greatly improve the lifetime of a WPSN using energy beamforming by a proper charging scheduling of energy beams. However, the supplied energy still may not meet the demand of the energy of the sensor nodes. This issue can be alleviated by deploying redundant sensor nodes, which not only increase the total harvested energy, but also decrease the energy consumption per node provided that an efficient scheduling of the sleep/awake of the nodes is performed. Such a problem of joint optimal sensor deployment, WET scheduling, and node activation is posed and investigated in this paper. The problem is an integer optimization that is challenging due to the binary decision variables and non-linear constraints. Based on the analysis of the necessary condition such that the WPSN be immortal, we decouple the original problem into a node deployment problem and a charging and activation scheduling problem. Then, we propose an algorithm and prove that it achieves the optimal solution under a mild condition. The simulation results show that the proposed algorithm reduces the needed nodes to deploy by approximately 16%, compared to a random-based approach. The simulation also shows if the battery buffers are large enough, the optimality condition will be easy to meet.
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39. |
- Du, Rong, 1989-, et al.
(author)
-
Poster : On the immortality of wireless sensor networks by wireless energy transfer — a node deployment perspective
- 2017
-
In: International Conference on Embedded Wireless Systems and Networks. - : Junction Publishing. ; , s. 206-207
-
Conference paper (peer-reviewed)abstract
- The lifetime of wireless sensor networks (WSNs) can be substantially extended by transferring energy wirelessly to the sensor nodes. In this poster, a wireless energy transfer (WET) enabled WSN is presented, where a base station transfers energy wirelessly to the sensor nodes that are deployed in several regions of interest, to supply them with energy to sense and to upload data. The WSN lifetime can be extended by deploying redundant sensor nodes, which allows the implementation of duty-cycling mechanisms to reduce nodes’ energy consumption. In this context, a problem on sensor node deployment naturally arises, where one needs to determine how many sensor nodes to deploy in each region such that the total number of nodes is minimized, and the WSN is immortal. The problem is formulated as an integer optimization, whose solution is challenging due to the binary decision variables and a non-linear constraint. A greedybased algorithm is proposed to achieve the optimal solution of such deployment problem. It is argued that such scheme can be used in monitoring systems in smart cities, such as smart buildings and water lines.
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40. |
- Du, Rong, 1989-, et al.
(author)
-
The sensable city : A survey on the deployment and management for smart city monitoring
- 2019
-
In: IEEE Communications Surveys and Tutorials. - : IEEE. - 1553-877X. ; 21:2, s. 1533-1560
-
Journal article (peer-reviewed)abstract
- In last two decades, various monitoring systems have been designed and deployed in urban environments, toward the realization of the so called smart cities. Such systems are based on both dedicated sensor nodes, and ubiquitous but not dedicated devices such as smart phones and vehicles’ sensors. When we design sensor network monitoring systems for smart cities, we have two essential problems: node deployment and sensing management. These design problems are challenging, due to large urban areas to monitor, constrained locations for deployments, and heterogeneous type of sensing devices. There is a vast body of literature from different disciplines that have addressed these challenges. However, we do not have yet a comprehensive understanding and sound design guidelines. This article addresses such a research gap and provides an overview of the theoretical problems we face, and what possible approaches we may use to solve these problems. Specifically, this paper focuses on the problems on both the deployment of the devices (which is the system design/configuration part) and the sensing management of the devices (which is the system running part). We also discuss how to choose the existing algorithms in different type of monitoring applications in smart cities, such as structural health monitoring, water pipeline networks, traffic monitoring. We finally discuss future research opportunities and open challenges for smart city monitoring.
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41. |
- Du, Rong, 1989-, et al.
(author)
-
Towards Immortal Wireless Sensor Networks by Optimal Energy Beamforming and Data Routing
- 2018
-
In: IEEE Transactions on Wireless Communications. - : Institute of Electrical and Electronics Engineers (IEEE). - 1536-1276 .- 1558-2248. ; 17:8, s. 5338-5352
-
Journal article (peer-reviewed)abstract
- The lifetime of a wireless sensor network (WSN) determines how long the network can be used to monitor the area of interest. Hence, it is one of the most important performance metrics for WSN. The approaches used to prolong the lifetime can be briefly divided into two categories: reducing the energy consumption, such as designing an efficient routing, and providing extra energy, such as using wireless energy transfer (WET) to charge the nodes. Contrary to the previous line of work where only one of those two aspects is considered, we investigate these two together. In particular, we consider a scenario where dedicated wireless chargers transfer energy wirelessly to sensors. The overall goal is to maximize the minimum sampling rate of the nodes while keeping the energy consumption of each node smaller than the energy it receives. This is done by properly designing the routing of the sensors and the WET strategy of the chargers. Although such a joint routing and energy beamforming problem is non-convex, we show that it can be transformed into a semi-definite optimization problem (SDP). We then prove that the strong duality of the SDP problem holds, and hence, the optimal solution of the SDP problem is attained. Accordingly, the optimal solution for the original problem is achieved by a simple transformation. We also propose a lowcomplexity approach based on pre-determined beamforming directions. Moreover, based on the alternating direction method of multipliers, the distributed implementations of the proposed approaches are studied. The simulation results illustrate the significant performance improvement achieved by the proposed methods. In particular, the proposed energy beamforming scheme significantly outperforms the schemes where one does not use energy beamforming, or one does not use optimized routing. A thorough investigation of the effect of system parameters, including the number of antennas, the number of nodes, and the number of chargers, on the system performance is provided. The promising convergence behavior of the proposed distributed approaches is illustrated.
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42. |
- Du, Zi-Ming
(author)
-
Biomarkers in nasopharyngeal carcinoma
- 2012
-
Doctoral thesis (other academic/artistic)abstract
- Nasopharyngeal carcinoma (NPC) is one of the most common malignancies in certain areas of Southern China, Southeastern Asia and Northern Africa. Currently, evaluation of NPC prognosis is mainly based on the tumor-node-metastasis (TNM) staging system. However, NPC patients with the same clinical stage often present different clinical courses, suggesting that the TNM staging is insufficient to predict prognosis of this disease. Therefore, it is important to find molecular biomarkers, which can help clinicians to identify NPC patients with worse prognosis and develop therapeutic interventions in NPC patients. This thesis presents the identification and investigation of mechanism of several novel markers in NPC. In the first paper, Caveolin-1 (Cav-1), a major structural component of caveolae, and CD147 (also known as extracellular matrix metalloproteinase inducer, EMMPRIN), a glycoprotein, were found to be overexpressed in NPC. Both Cav-1 and CD147 expression levels correlated significantly with metastasis and poor prognosis of NPC patients. Further studies revealed that Cav-1 and CD147 enhance NPC cell migration, which is associated with MMP-3 and MMP-11 (active) secretion. The role of microRNA-155 (miR-155) is associated with oncogenesis of several human tumors. In the second paper, miR-155 was found to be upregulated in NPC cell lines and clinical samples. EBV encoded LMP1 and LMP2A could further enhance the expression of miR-155 in NPC CNE1 and TW03 cells. JMJD1A was identified as a direct target of miR-155 in NPC. Downregulation of JMJD1A was significantly correlated with N stage of the TNM classification, a lower five-year survival rate, and a lower five-year disease-free survival rate of NPC patients. Spleen tyrosine kinase (Syk) is a nonreceptor tyrosine kinase and often aberrantly expressed in human cancers. In the third paper, high expression of Syk was detected in 24% of NPC cases. High expression of Syk, resulted partly from LMP2A expression in NPC, is associated with tumor recurrence and poor prognosis of NPC patients. Human chromosome 3 (Chr. 3) contains clusters of tumor suppressor genes (TSGs) involved in many cancer types. In the fourth paper, using Not I Chr. 3 microarray, ten candidate TSGs were found in NPC. Among them, the CpG island in the promoter region of Wingless-type Mouse mammary tumor virus integration site family, member 7A (WNT7a) and the intron 1 region of Integrin α9 (ITGA9) were confirmed to be hypermethylated in NPC by bisulfite sequencing and methylation specific PCR. Demethylating agent 5-aza-2′-deoxycytidine (5-aza-CdR) treatment could restore the expression of WNT7a and ITGA9 in NPC cell lines. Furthermore, WNT7a and ITGA9 were downregulated in NPC clinical samples. As both proteins execute significant functions related to the tumor cell biology, the potential of WNT7a and ITGA9 as diagnosis or therapeutic targets for NPC should be considered.
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43. |
- El-Seedi, Hesham, et al.
(author)
-
Chemistry and the Potential Antiviral, Anticancer, and Anti-Inflammatory Activities of Cardiotonic Steroids Derived from Toads
- 2022
-
In: Molecules. - : MDPI AG. - 1431-5157 .- 1420-3049. ; 27:19
-
Research review (peer-reviewed)abstract
- Cardiotonic steroids (CTS) were first documented by ancient Egyptians more than 3000 years ago. Cardiotonic steroids are a group of steroid hormones that circulate in the blood of amphibians and toads and can also be extracted from natural products such as plants, herbs, and marines. It is well known that cardiotonic steroids reveal effects against congestive heart failure and atrial fibrillation; therefore, the term cardiotonic has been coined. Cardiotonic steroids are divided into two distinct groups: cardenolides (plant-derived) and bufadienolides (mainly of animal origin). Cardenolides have an unsaturated five-membered lactone ring attached to the steroid nucleus at position 17; bufadienolides have a doubly unsaturated six-membered lactone ring. Cancer is a leading cause of mortality in humans all over the world. In 2040, the global cancer load is expected to be 28.4 million cases, which would be a 47% increase from 2020. Moreover, viruses and inflammations also have a very nebative impact on human health and lead to mortality. In the current review, we focus on the chemistry, antiviral and anti-cancer activities of cardiotonic steroids from the naturally derived (toads) venom to combat these chronic devastating health problems. The databases of different research engines (Google Scholar, PubMed, Science Direct, and Sci-Finder) were screened using different combinations of the following terms: cardiotonic steroids, anti-inflammatory, antiviral, anticancer, toad venom, bufadienolides, and poison chemical composition. Various cardiotonic steroids were isolated from diverse toad species and exhibited superior anti-inflammatory, anticancer, and antiviral activities in in vivo and in vitro models such as marinobufagenin, gammabufotalin, resibufogenin, and bufalin. These steroids are especially difficult to identify. However, several compounds and their bioactivities were identified by using different molecular and biotechnological techniques. Biotechnology is a new tool to fully or partially generate upscaled quantities of natural products, which are otherwise only available at trace amounts in organisms.
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44. |
- El-Seedi, Hesham, et al.
(author)
-
Exploring natural products-based cancer therapeutics derived from egyptian flora
- 2021
-
In: Journal of Ethnopharmacology. - : Elsevier BV. - 0378-8741 .- 1872-7573. ; 269
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Research review (peer-reviewed)abstract
- Ethnopharmacological relevance: Egyptian plants are a rich source of natural molecules, representing considerable biodiversity due to climate variations between the Northern, Southern, Eastern and Western regions of the country. Sinai is considered a precious nature reserves preserving flora, fauna, marine organisms, and historical habitats with ancient origins. Here, traditional medicinal approaches have been used for hundreds of years. Healthy lifestyles, low levels of stress and microbial infections, and a dependence on flora and herbal medicine might in combination explain why the burden of cancer is lower in some regions than in others.Aim of the study: The primary aim of this review is to document the plants and natural products that are used as foods and medicines in Egypt, in general, and in Sinai, in particular, with a focus on those with demonstrated anticancer activities. The documented traditional uses of these plants are described, together with their chemical and pharmacological activities and the reported outcomes of clinical trials against cancer.Materials and methods: A literature search was performed to identify texts describing the medicinal plants that are cultivated and grown in Egypt, including information found in textbooks, published articles, the plant list website (http://www.theplantlist.org/), the medicinal plant names services website (http://mpns.kew.org/mpns-portal/), and web databases (PubMed, Science Direct, and Google Scholar).Results and discussion: We collected data for most of the plants cultivated or grown in Egypt that have been previously investigated for anticancer effects and reported their identified bioactive elements. Several plant species, belonging to different families and associated with 67 bioactive compounds, were investigated as potential anticancer agents (in vitro studies). The most potent cytotoxic activities were identified for the families Asteraceae, Lamiaceae, Chenopodiaceae, Apocynaceae, Asclepiadaceae, Euphorbiaceae, Gramineae, and Liliaceae. The anticancer activities of some species, such as Punica granatum L., Nerium oleander L., Olea europea L., Matricaria chamomilla L., Cassia acutifolia L., Nigella sativa L., Capsicum frutescens L., Withania somnifera L., and Zingiber officinale Roscoe, have been examined in clinical trials. Among the various Egyptian plant habitats, we found that most of these plants are grown in the North Sinai, New-Delta, and Giza Governorates.Conclusion: In this review, we highlight the role played by Egyptian flora in current medicinal therapies and the possibility that these plants may be examined in further studies for the development of anticancer drugs. These bioactive plant extracts form the basis for the isolation of phytochemicals with demonstrated anticancer activities. Some active components derived from these plants have been applied to preclinical and clinical settings, including resveratrol, quercetin, isoquercetin, and rutin.
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45. |
- El-Seedi, Hesham R., et al.
(author)
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Honeybee products : An updated review of neurological actions
- 2020
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In: Trends in Food Science & Technology. - : Elsevier BV. - 0924-2244 .- 1879-3053. ; 101, s. 17-27
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Research review (peer-reviewed)abstract
- Background: According to the World Health Organization, two billion people will attain the age of 60 years or more by 2050. Ageing is a major risk factor for a number of neurodegenerative disorders, which currently possess challenge to the global health status, carrying economic and social consequences. Therefore, attention has been dedicated towards the development of neuroprotective agents derived from natural sources. Honeybee products, such as honey, bee pollen, bee bread, propolis, royal jelly, beeswax, and bee venom have been used for therapeutic purposes since ancient times in Egypt, Greece, and China. Despite the emergence of modern medicine, bee products remain clinically relevant owing to their potential as anti-inflammatory, anti-oxidant, and neuroprotective agents.Scope and approach: This review demonstrates the potential of bee products against neurological disorders in the light of the current literature.Key findings and conclusions: Bee products and individual isolated components have enormous therapeutic potential for multiple neurological disorders. The different studies show overall neuroprotective and nerve-tonic characteristics of bee products, mainly due to their anti-oxidant, anti-inflammatory and anti-apoptotic features. However, some limitations such as allergic reactions and the cytotoxic effect of some bee products warrant a special care in its development as drug leads in future studies.
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46. |
- Engert, Andreas, et al.
(author)
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The European Hematology Association Roadmap for European Hematology Research : a consensus document
- 2016
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In: Haematologica. - Pavia, Italy : Ferrata Storti Foundation (Haematologica). - 0390-6078 .- 1592-8721. ; 101:2, s. 115-208
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Journal article (peer-reviewed)abstract
- The European Hematology Association (EHA) Roadmap for European Hematology Research highlights major achievements in diagnosis and treatment of blood disorders and identifies the greatest unmet clinical and scientific needs in those areas to enable better funded, more focused European hematology research. Initiated by the EHA, around 300 experts contributed to the consensus document, which will help European policy makers, research funders, research organizations, researchers, and patient groups make better informed decisions on hematology research. It also aims to raise public awareness of the burden of blood disorders on European society, which purely in economic terms is estimated at (sic)23 billion per year, a level of cost that is not matched in current European hematology research funding. In recent decades, hematology research has improved our fundamental understanding of the biology of blood disorders, and has improved diagnostics and treatments, sometimes in revolutionary ways. This progress highlights the potential of focused basic research programs such as this EHA Roadmap. The EHA Roadmap identifies nine 'sections' in hematology: normal hematopoiesis, malignant lymphoid and myeloid diseases, anemias and related diseases, platelet disorders, blood coagulation and hemostatic disorders, transfusion medicine, infections in hematology, and hematopoietic stem cell transplantation. These sections span 60 smaller groups of diseases or disorders. The EHA Roadmap identifies priorities and needs across the field of hematology, including those to develop targeted therapies based on genomic profiling and chemical biology, to eradicate minimal residual malignant disease, and to develop cellular immunotherapies, combination treatments, gene therapies, hematopoietic stem cell treatments, and treatments that are better tolerated by elderly patients.
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47. |
- Fan, Weiwei, et al.
(author)
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Characterizations of a Food Decapeptide Chelating with Zn(II)
- 2020
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In: EFOOD. - : John Wiley & Sons. - 2666-3066. ; 1:4, s. 326-331
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Journal article (peer-reviewed)abstract
- Walnut proteins and peptides have been reported to have great zinc-carrying activity. In this study, the decapeptide EPNGLLLPQY (WP-10) derived from walnut protein has been prepared to figure out zinc binding mechanisms and structure-activity relationships. The space-conformation of this peptide has converted after being chelated with Zn(II). As to secondary structure, the beta-sheet structure of the peptide turned into alpha-helix and beta-turn structure. According to the atomic absorption spectra analysis, one peptide could bind with one Zn(II) via four different binding sites. The signals of different groups in infrared spectroscopy have shifted before and after chelation, and the major functional groups of this peptide involved in chelation are -NH2 and -C=O. GLU1, PRO2, ASP3, GLU4, and LEU6, and the molecular docking proved their participation in the chelating with Zn(II). (c) 2020 International Association of Dietetic Nutrition and Safety. Publishing services by Atlantis Press International B.V. This is an open access article distributed under the CC BY-NC 4.0 license (http://creativecommons.org/licenses/by-nc/4.0/).
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48. |
- Feng, Jie, et al.
(author)
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Task Scheduling and Resource Management in MEC-Enabled Computing Networks
- 2022
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In: Mobile Networks And Management, MONAMI 2021. - Cham : Springer Nature. ; , s. 127-137
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Conference paper (peer-reviewed)abstract
- The rapid development of the fifth generation (5G) promotes a variety of new applications, which will pose a huge challenge to the computing resources of networks. Computing networks is a promising technology, which can provide ubiquitous computing resources for applications in 5G. However, resource optimization in computing networks is still an open problem. In this paper, we propose a novel resource allocation framework for computing networks to investigate the energy consumption minimization problem in terms of delay constraint. To tackle the problem, we propose a dynamic task scheduling and resource allocation algorithm to utilizing the Lyapunov optimization method, which doesn't need to know any prior knowledge of networks. In order to reduce the complexity of solving the problem, we decompose the original problem into several sub-problem to solve. Particulary, the solutions of transmit power and subcarrier assignment are obtained by using the Lagrangian dual decomposition method. The solutions of computation time, postponing time, and CPU-cycle frequency are achieved in the closed form. Simulation results show that the performance of the proposed algorithms and can achieve the tradeoff between the average delay and the average energy consumption.
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49. |
- Feron, Romain, et al.
(author)
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RADSex : A computational workflow to study sex determination using restriction site-associated DNA sequencing data
- 2021
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In: Molecular Ecology Resources. - : John Wiley & Sons. - 1755-098X .- 1755-0998. ; 21:5, s. 1715-1731
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Journal article (peer-reviewed)abstract
- The study of sex determination and sex chromosome organization in nonmodel species has long been technically challenging, but new sequencing methodologies now enable precise and high-throughput identification of sex-specific genomic sequences. In particular, restriction site-associated DNA sequencing (RAD-Seq) is being extensively applied to explore sex determination systems in many plant and animal species. However, software specifically designed to search for and visualize sex-biased markers using RAD-Seq data is lacking. Here, we present RADSex, a computational analysis workflow designed to study the genetic basis of sex determination using RAD-Seq data. RADSex is simple to use, requires few computational resources, makes no prior assumptions about the type of sex-determination system or structure of the sex locus, and offers convenient visualization through a dedicated R package. To demonstrate the functionality of RADSex, we re-analysed a published data set of Japanese medaka, Oryzias latipes, where we uncovered a previously unknown Y chromosome polymorphism. We then used RADSex to analyse new RAD-Seq data sets from 15 fish species spanning multiple taxonomic orders. We identified the sex determination system and sex-specific markers in six of these species, five of which had no known sex-markers prior to this study. We show that RADSex greatly facilitates the study of sex determination systems in nonmodel species thanks to its speed of analyses, low resource usage, ease of application and visualization options. Furthermore, our analysis of new data sets from 15 species provides new insights on sex determination in fish.
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50. |
- Fu, Baifeng, et al.
(author)
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Identification and characterisation of taste-enhancing peptides from oysters (Crassostrea gigas) via the Maillard reaction
- 2023
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In: Food Chemistry. - : Elsevier. - 0308-8146 .- 1873-7072. ; 424
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Journal article (peer-reviewed)abstract
- Oysters, which are flavourful edible marine products, have been utilised to produce Maillard reaction products (MRPs), which contribute to saltiness enhancement. Here, the molecular weight distribution, free amino acids, and taste characteristics of MRPs were analysed, while ultraviolet light was used to observe the Maillard reaction. Both thermal degradation and cross-linking reactions occur during the Maillard reaction. When the Maillard reaction time was 90 min, the saltiness, umami, and richness of the MRPs peaked, however bitterness reached its lowest value. Moreover, at an MRP concentration of 1.5 mg/mL, salts were reduced by 35.71% in a 3 mg/mL sodium chloride solution without reducing saltiness, based on sensory evaluation. Glycation sites of the MRPs, which are crucial for saltiness enhancement and derived from a variety of protein sources, were determined using nano-HPLC-MS/MS analysis. Our study establishes the foundation for preparing salt-enhancing peptides, accelerating the popularisation of oyster-derived flavouring agents.
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