Unmanned aerial vehicle-aided cooperative regenerative relaying network under various environments

This paper studies a cooperative relay network that comprises an unmanned aerial vehicle (UAV) enabling amplify-and-forward (AF) and power splitting (PS) based energy harvesting. The considered system can be constructed in various environments such as suburban, urban, dense urban, and high-rise urban where the air-to-ground channels are model by a mixture of Rayleigh and Nakagami-m fading. Then, outage probability and ergodic capacity are provided under different environment-based parameters. Optimal PS ratios are also provided under normal and high transmit power regimes. Finally, the accuracy of the analytical results is validated through Monte Carlo methods

Temporal fluctuation of multidrug resistant salmonella typhi haplotypes in the mekong river delta region of Vietnam.

BACKGROUND: typhoid fever remains a public health problem in Vietnam, with a significant burden in the Mekong River delta region. Typhoid fever is caused by the bacterial pathogen Salmonella enterica serovar Typhi (S. Typhi), which is frequently multidrug resistant with reduced susceptibility to fluoroquinolone-based drugs, the first choice for the treatment of typhoid fever. We used a GoldenGate (Illumina) assay to type 1,500 single nucleotide polymorphisms (SNPs) and analyse the genetic variation of S. Typhi isolated from 267 typhoid fever patients in the Mekong delta region participating in a randomized trial conducted between 2004 and 2005. PRINCIPAL FINDINGS: the population of S. Typhi circulating during the study was highly clonal, with 91% of isolates belonging to a single clonal complex of the S. Typhi H58 haplogroup. The patterns of disease were consistent with the presence of an endemic haplotype H58-C and a localised outbreak of S. Typhi haplotype H58-E2 in 2004. H58-E2-associated typhoid fever cases exhibited evidence of significant geo-spatial clustering along the Sông H u branch of the Mekong River. Multidrug resistance was common in the established clone H58-C but not in the outbreak clone H58-E2, however all H58 S. Typhi were nalidixic acid resistant and carried a Ser83Phe amino acid substitution in the gyrA gene. SIGNIFICANCE: the H58 haplogroup dominates S. Typhi populations in other endemic areas, but the population described here was more homogeneous than previously examined populations, and the dominant clonal complex (H58-C, -E1, -E2) observed in this study has not been detected outside Vietnam. IncHI1 plasmid-bearing S. Typhi H58-C was endemic during the study period whilst H58-E2, which rarely carried the plasmid, was only transient, suggesting a selective advantage for the plasmid. These data add insight into the outbreak dynamics and local molecular epidemiology of S. Typhi in southern Vietnam

User Selection Approaches to Mitigate the Straggler Effect for Federated Learning on Cell-Free Massive MIMO Networks

This work proposes UE selection approaches to mitigate the straggler effect for federated learning (FL) on cell-free massive multiple-input multiple-output networks. To show how these approaches work, we consider a general FL framework with UE sampling, and aim to minimize the FL training time in this framework. Here, training updates are (S1) broadcast to all the selected UEs from a central server, (S2) computed at the UEs sampled from the selected UE set, and (S3) sent back to the central server. The first approach mitigates the straggler effect in both Steps (S1) and (S3), while the second approach only Step (S3). Two optimization problems are then formulated to jointly optimize UE selection, transmit power and data rate. These mixed-integer mixed-timescale stochastic nonconvex problems capture the complex interactions among the training time, the straggler effect, and UE selection. By employing the online successive convex approximation approach, we develop a novel algorithm to solve the formulated problems with proven convergence to the neighbourhood of their stationary points. Numerical results confirm that our UE selection designs significantly reduce the training time over baseline approaches, especially in the networks that experience serious straggler effects due to the moderately low density of access points.Comment: submitted for peer review

Mineralogical characteristics of graphite ore from Bao Ha deposit, Lao Cai Province and proposing a wise use

Graphite, especially, high quality graphite can be used in many industrial applications including metallurgy, batteries, fuel cells, and refractories. In 2011, Vietnam Ministry of Natural Resources and Environment issued a mineral exploration license to explore Bao Ha graphite deposit, Bao Yen district, Lao Cai Province. The studied samples were taken from 3 drill holes of the Bao Ha largest ore body. Different methods including light microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and carbon and sulfur analyzer were performed to identify its lithological and mineralogical characteristics as well as graphite quality, then propose a wise use of the resource. The Bao Ha graphite is characterized as disseminated flake graphite in massive form, which developed in the sillimanite schist and quartz-biotite schist of the Ngoi Chi formation. Graphite flakes occur as distorted clusters of flaky plates/flakes within 50÷500 mm, which is the medium size in comparison with the general grain size of graphite flake. Graphite particle makes up 33÷43% by volume and graphitic content (Cg) makes up 10.0÷11.7 wt.%. Impurities include mainly quartz, biotite, and feldspar (combining of K-feldspar and anorthite, the primary ore) or kaolinite (the weathered ore). This graphite ore should be refined to reach an ore concentration of at least 90% Cg for domestic industries of metallurgy, batteries, thermal materials, and refractories as well as for exports.ReferencesAsbury Carbons, 2015. Natural graphite - Introduction to natural graphite. http://asbury.com/technical-presentations-papers/materials-in-depth/natural-graphite/(Accessed on April 26, 2015). Bergmann J., Friedel P., Kleeberg R., 1998. BGMN - a new fundamental parameters based Rietveld program for laboratory X-ray sources, its use in quantitative analysis and structure investigations. CPD Newsletter 20, 5-8. Bien Xuan Thanh (Editor), 2014. Exploration of graphite deposit in Bao Ha area, Bao Ha community, Bao Yen district, Lao Cai province. Report. Song Da Lao Cai Mining Joint Stock Company. Cameron E., 1960. Graphite: Industrial Minerals and Rocks. Seeley W. Mudd Series, AIME (Chapter 20). European Commission, 2010. Report lists 14 critical mineral raw materials. http://europa.eu/rapid/press-release_MEMO-10-263_en.htm?locale=en. (Accessed on April 26, 2015). Garnier V., Giuliani G., Ohnenstetter D., Fallick A.E., Dubessy J., Banks D., Vinh H.Q., Lhomme T., Maluski H., Pêcher A., Bakhsh K.A., Long P.V., Trinh, P.T., Schwarz D., 2008. Marble-hosted ruby deposits from Central and Southeast Asia: Towards a new genetic model. Ore Geology Reviews, 34, 169-191. Hoang Thai Son (Editor), 1997. Geological and Mineral Resources Map of Vietnam at 1:50,000 scale, sheets Doan Hung - Yen Binh. General Department of Geology and Minerals of Vietnam. Hoang Thai Son, Pham Ngoc Thach, Nguyen The Trung, Chu Hong Phong, Nguyen Ngoc Dung, Pham Xuan Doanh, 2000. Disscussion about metamorphism facies of Song Hong Series. Proceedings. General Department of Geology and Minerals of Vietnam. Industrial Minerals, 2011. Supply Situation Report: Graphite demand soars above precrisis levels. http://www.indmin.com/Print.aspx?ArticleId=2797590 (Accessed on April 04, 2011). Industrial Minerals, 2012. The Natural Graphite Report 2012-Data, analysis and forecast for the next five years. http://www.indmin.com/downloads/reports/graphite2012.pdf. Kleeberg R., Ufer K., Bergmann, 2005. The Quantification of Disordered Clay Minerals by the Rietveld Method - Some Practical Aspects. Presentation at the 42nd Annual Meeting of the Clay Minerals Society, June 11-15, 2005, Burlington/Vermont. Lu X. and Forssberg E., 2001. Flotation selectivity and upgrading of Woxna fine graphite concentrate. Mineral Engineering, 14(l l), 1541-1543. Lu X. and Forssberg E., 2002. Preparation of high-purity and low-sulphur graphite from Woxna fine graphite concentrate by alkali roasting. Minerals Engineering. 15(10), 755-757. Luu Huu Hung (Editor), 2001. Evaluation on graphite of Bao Ha area, Bao Yen, Lao Cai. Report. General Department of Geology and Minerals of Vietnam. Ministry of Industry and Trade, 2016. Circular - amending and supplementing a number of articles of the Minister of Industry and Trade’s circular no. 41/2012/TT-BCT of December 21, 2012, providing the export of minerals (July 05, 2016). https://thuvienphapluat.vn/van-ban/Xuat-nhap-khau/Thong-tu-12-2016-TT-BCT-sua-doi-41-2012-TT-BCT-xuat-khau-khoang-san-316914.aspx Mitchell C.J., 1993. Industrial Minerals Laboratory Manual - Flake Graphite. Technical Report. British Geological Survey. Nguyen Vinh, Phan Truong Thi, 1973. Distribution of contact and dynamic metamorphic rocks in Yen Bai - Nghia Lo area. Journal of Sciences and Techniques of Mining and Geology (ISSN: 1859-1469), 22, 1-13. Hanoi University of Mining and Geology. Northern Graphite Corporation, 2015. Bissett Creek Project. http://northerngraphite.com/bissett-creek-project/ Accessed on April 30, 2015. Persistence Market Research, 2015. Global market study on graphite: Battery segment to witness highest growth by 2020. http://www.persistencemarketresearch.com/market-research/graphite-market.asp. Pham Van Long, Hoang Quang Vinh, Garnier V., Giuliani G., Ohnenstetter D., Lhomme T., Schwarz D., Fallick A., Dubessy J., Phan Trong Trinh, 2004. Gem corundum deposits in Vietnam. Journal of Gemmology, 29(3), 129-147. Pierson H.O., 1993. Handbook of carbon, graphite, diamond and fullerenes - Properties, Processing and Applications. Noyes Publications. Plumbago Co., 2013. What is graphite. http://www.plumbagographite.com/graphite-story/what-is-graphite. (Accessed on April 26, 2015). Rodas M., Luque F.J., Barrenechea J.F., Fernández-Caliani J.C., Miras A., Fernández Rodríguez C., 2000. Graphite occurrences in the Low-Pressure/High-Temperature metamorphic belt of the Sierra de Aracena (Southern Iberian Massif). Mineralogical Magazine, 64, 801-814. Simandl G.J., Paradis S., Valiquette G., Jacob H.L., 1995. Crystalline graphite deposits, classification and economic potential. Proceedings of 28th Forum on the Geology of Industrial Minerals, Marinsburg, West Virginia, May 3-8, 1992, 168-174. Simandl G.J., Paradis S., Akam C., 2015. Graphite deposit types, their origin, and economic significance. In: Simandl G.J. and Neetz M., (Eds.), Symposium on Strategic and Critical Materials Proceedings, November 13-14, 2015, Victoria, British Columbia, British Columbia Ministry of Energy and Mines, British Columbia Geological Survey Paper 2015-3, 163-171. Tran Thi Hien, Vu Tan Co, Chu Van Hoan, Vu Van Ha, Bui Van Ngu, Nguyen Duc Minh, Nguyen Bao Linh, Tran Duc Dung, 2008. Study about mineral processing technology for graphite ore from Nam Thi mine - Lao Cai province. Report. National Institute of Mining - Metallurgy Science and Technology, Vietnam. Tran Van Tri, Vu Khuc (Editors), 2001. Geology and Earth Resources of Vietnam. General Department of Geology and Minerals of Vietnam. Publishing House for Science and Technology, 645p. Tran Xuyen (Editor), 1988. Geological and Mineral Resources Map of Vietnam at 1:200,000 scale, sheets Bac Quang - Ma Quan. Map explanation. General Department of Geology and Minerals of Vietnam. U.S Geological Survey, 2007. 2007 Minerals Yearbook - Graphite. U.S Geological Survey, 10. U.S Geological Survey, 2012. Mineral commodity summaries 2012. U.S Geological Survey, 68-69. U.S Geological Survey, 2017. Mineral commodity summaries 2017. U.S Geological Survey, 74-75. Ufer K., Stanjek H., Roth G., Dohrmann R., Kleeberg R., Kaufhold S., 2008. Quantitative phase analysis of bentonites by the Rietveld method. Clay Mineral 56(2), 272-282. http://dx.doi.org/10.1346/CCMN.2008.0560210. Volkova S.A., Il’icheva O.M., Kuznetsov O.B., 2011. X-ray study of the graphite-bearing rocks from the Pestpaksha ore occurrence and structural features of graphite. Lithology and Mineral Resources, 46(4), 363-368. Vietnam Standards and Quality Institute, 1989. TCVN 4688:1989 Graphite concentrate - Marks and technical requirements.

Fed-LSAE: Thwarting Poisoning Attacks against Federated Cyber Threat Detection System via Autoencoder-based Latent Space Inspection

The significant rise of security concerns in conventional centralized learning has promoted federated learning (FL) adoption in building intelligent applications without privacy breaches. In cybersecurity, the sensitive data along with the contextual information and high-quality labeling in each enterprise organization play an essential role in constructing high-performance machine learning (ML) models for detecting cyber threats. Nonetheless, the risks coming from poisoning internal adversaries against FL systems have raised discussions about designing robust anti-poisoning frameworks. Whereas defensive mechanisms in the past were based on outlier detection, recent approaches tend to be more concerned with latent space representation. In this paper, we investigate a novel robust aggregation method for FL, namely Fed-LSAE, which takes advantage of latent space representation via the penultimate layer and Autoencoder to exclude malicious clients from the training process. The experimental results on the CIC-ToN-IoT and N-BaIoT datasets confirm the feasibility of our defensive mechanism against cutting-edge poisoning attacks for developing a robust FL-based threat detector in the context of IoT. More specifically, the FL evaluation witnesses an upward trend of approximately 98% across all metrics when integrating with our Fed-LSAE defense

Anatomical Characteristics and Variants of Prostatic Artery in Patients of Benign Hyperplasia Prostate by Digital Subtraction Angiography

AIM: This work is aimed to describe anatomical features and variants of the prostatic artery (PA) using digital subtraction angiography (DSA). METHODS: This is a descriptive statistic study. We reviewed the DSA of 348 patients, who had a PA embolisation to reduce the benign prostatic hyperplasia (BPH) symptoms at Radiology Department of Bach Mai Hospital from Oct – 2014 to Oct – 2018. RESULTS: PA was found at 660 pelvic halves, of which 30 pelvic halves (4.5%) had two PAs, 630 pelvic halves had one PA. In terms of the origin of PA, in total 690 PAs, the percentage of type 1, 2, 3, 4 and 5 was successively 33.9%, 13.9%, 18.3%, 23.9% and 10.4%, respectively. Atherosclerosis of PA observed in 20.9%. The ‘corkscrew’ pattern was found in 30.4%. The average diameter of PA was 1.5 ± 0.34mm. The anastomosis of PA with surrounding arteries was common. PA may supply rectum (6.1%), seminal vesical (9.6%), bladder (5.2%), contralateral prostatic parenchyma (13.0%), surrounding soft-tissues (3.5%). CONCLUSION: The common trunk with SVA superior vesical artery was the most common origin of PA. Anastomoses of PA with surrounding tissues were complex

Genetic variation and outcrossing rate of Dipterocarpus dyeri in the Tan Phu tropical rain forest (Dong Nai), Vietnam

Dipterocarpus dyeri (Dipterocarpaceae) is widely distributed in lowland rainforests in southeastern Vietnam. Due to over- exploitation and habitat destruction in the 1980s and 1990s, this species is listed as threatened. Understanding the genetic variation and mating rate among D. dyeri population that occurs in forest patches is necessary to establish effectively conservation strategies for this species. To conserve the species in tropical forests, genetic diversity and mating rate were investigated using eight microsatellites (single sequence repeat, SSR) as markers. All of the eight loci were polymorphic. A total of 36 different alleles were observed across the loci screened. The SSR data indicated high genetic diversity (NA = 4.5; HO = 0.542 and HE = 0.667) and high inbreeding value, FIS= 0,182. The mating system parameters were determined using the mixed mating model and the results indicated high outcrossing rate (tm=0.81 and ts=0.675) and lowselfing rate (0.19). Difference of tm-ts value indicated that inbreeding contributed to selfing rate for this species in the Tan Phu tropical rain forest. The results reflected that D. dyeri habitat in this area has been restored and the number of individuals was high, about 500 individuals. However, seedlings were not found so far in this study. These results indicated the importance of conserving of the genetic resources of Dipterocarpus dyeri species in the Tan Phu rain forest. The conservation strategy should include an establishment of an ex-situ conservation site with new big population for this species from all genetic groups, which might improve its fitness under different environmental stresses. 

Transformation Chlorophyll a of Spirulina platensis to Chlorin e6 Derivatives and Several Applications

BACKGROUND: Spirulina platensis contains a large amount of chlorophylls, chlorophyll a, that are starting materials to synthesize functionalized chlorins. Chlorin e6 (Ce6) as well as its derivatives are second generation sensitizers using in photodynamic therapy (PDT) of various cancers. In this study, we transfer chlorophyll a of S. platensis to Ce6derivatives and determine their several applications. AIM: to evaluate the effects of Ce6 derivatives to treat cancer cells. METHODS: Ce6 trimethylester was created from methyl pheophorbide a2 in S. platensis provided by the Hidumi Company, Nghe An province, Viet Nam. Hela cells were incubated with Ce6 trimethylester and the irradiated with the diode laser dose of 1.2 J/cm2/min through the system of filters £ 650 nm. MTT assay and clonogenic assay were used to determine survival rate and cloning efficiency of cells. Antimicrobial effect of Ce6 trimethylester with halogen light were studied with Propionibacterium acnes VTCC 0218 and Staphylococcus aureus VTCC 0173. RESULTS: From dry biomass (700 g) of S. platensis, after extracting chlorophyll a and methanolysis, 4.2 g of methyl pheophorbide a was obtained. The reaction to give Ce6 trimethylester with 82% yield was performed with potassium hydroxide (KOH) in MeOH/THF/CHCl3. After irradiation with a 650 nm laser at 1.2 J, the cell viability in all samples decreased with Ce6 trimethylester treatment, the survival declining trend of Hela cells treated with Ce6 trimethylester were proportional when concentration of Ce6 trimethylester increased. The rate of colony formation was declined as the concentration of Ce6 trimethylester treated was increased. The growth of both S. aureus and P. acnes can be inactivated by Ce6 trimethylester PDT. The MIC99 value against P. acnes VTCC 0218 and S. aureus VTCC 0173 of Ce6 trimethylester with halogen light was 1.25 μg/ml. CONCLUSION: The Ce6 trimethylester from S. platensis cultivated in Viet Nam could be used as a potential photosentizer for photodynamic therapy for treatment of cancer and acne

A study of consumer behavior and willingness to pay towards cosmetic products of generation Z in Hochiminh city

The global cosmetics industry is experiencing robust growth and Generation Z (Gen Z) is a potential customer source of this market. This research examines customers’ intentions to purchase cosmetic goods of Gen Z in Hochiminh city using perceived value factors as the antecedents of attitude in the model. A cross-sectional study, applying a convenient sampling method, was conducted to collect data from Gen Z people in January 2023. There were no specific cosmetics products included in the study. Descriptive analysis and Partial Least Square (PLS) method of Structural Equation Modeling (SEM) with SmartPLS 4.0.8.7 software were used to analyze the research data. The PLS-SEM analysis of 723 responses showed that attitudes toward purchasing cosmetic products are significantly positively impacted by perceived environmental value. A more positive attitude would result from increased brand credibility and product understanding of cosmetics. There was no evidence to support the impact of other perceived values (specifically, health, safety, social, spiritual, and ethical) on attitudes toward consumer behavior. Attitude was important in predicting willingness to pay (both direct and indirect). This study helps industry professionals to advance the qualities of cosmetic products by increasing and improving environmental value, product knowledge, and brand credibility. The eco-friendly pattern of production and marketing strategies focusing on product ingredients, manufacturing processes, and quality standards are necessary to enhance brand credibility and product understanding, align with consumer preferences and achieve greater success in the market