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Growth of the tropical Pinus kesiya as influenced by climate and nutrient availability along an elevational gradient

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Journal of Plant Ecology 2020年第1期13卷 97-106页

作者： le tuan ho Raimund Schneider Frank M.Thomas Department of Geobotany University of TrierFaculty of Regional and Environmental SciencesBehringstraße 2154296 TrierGermany Department of Forest Resources Management Faculty of ForestryNong Lam University HCMCThu Duc DistrictHo Chi Minh CityVietnam Department of Soil Science University of TrierFaculty of Regional and Environmental SciencesBehringstraße 2154296 TrierGermany

与温带地区相比,人们对在热带山脉中,尤其是热带针叶林中,沿海拔梯度的个体树种生长减少的原因知之甚少。我们的研究目的是检验气候或土壤条件是否会导致在高海拔分布的卡西亚松(Pinus kesiya,一种在南亚和东南亚广泛分布的松树)的生长... 详细信息

与温带地区相比,人们对在热带山脉中,尤其是热带针叶林中,沿海拔梯度的个体树种生长减少的原因知之甚少。我们的研究目的是检验气候或土壤条件是否会导致在高海拔分布的卡西亚松(Pinus kesiya,一种在南亚和东南亚广泛分布的松树)的生长减少。我们对越南中南部山脉中沿海拔梯度约在900~2000米之间的卡西亚松的树干直径增量和其年轮中^(13)C(△^(13)C)的同位素判别进行分析。同时确定其生长与△^(13)C、气候和土壤变量的关系。研究发现,树木的断面积生长量(BAI)与温度或降水之间没有一致的相关关系。相反,沿海拔梯度,我们发现BAI与△^(13)C以及与上层矿质土壤的C/N比和δ^(15)N特征呈显著负相关。BAI与土壤中有效磷(P_(a))和“碱性”阳离子(钙、镁、钾)的浓度呈正相关。我们的结论是,较高海拔下的较低温度会对树木生长产生间接影响,主要通过产生较高的C/N比并降低氮(N)和P矿化率而产生作用,而这些影响因其他负面反馈而进一步受到阻碍。主要包括:降水增加的淋溶作用而导致较低浓度的“碱性”阳离子以及较高海拔土壤矿化的N和P的有效性降低。本研究结果可以进一步解释卡西亚松的最高生长极限以及该物种在其他山区出现的情况。

关键词：树木生态学松树指示年土壤养分稳定同位素

New Collective Signatures Based on the Elliptic Curve Discrete Logarithm Problem

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Computers, Materials & Continua 2022年第10期73卷 595-610页

作者： tuan Nguyen Kim Duy ho Ngoc Nikolay A.Moldovyan School of Computer Science Duy Tan UniversityDa NangVietnam Department of Information Technology Ha NoiVietnam ITMO University St.PetersburgRussia

There have been many digital signature schemes were developed based on the discrete logarithm problem on a finite *** this study,we use the elliptic curve discrete logarithm problem to build new collective signature *** cryptosystem on elliptic curve allows to generate digital signatures with the same level of security as other cryptosystems but with smaller *** extend practical applicability and enhance the security level of the group signature protocols,we propose two new types of collective digital signature schemes based on the discrete logarithm problem on the elliptic curve:i)the collective digital signature scheme shared by several signing groups and ii)the collective digital signature scheme shared by several signing groups and several individual *** two new types of collective signatures have combined the advantages of group digital signatures and collective digital *** signatures have a fixed size and do not depend on the number of members participating in the creation of the final collective *** of the advantages of the proposed collective signature protocols is that they can be deployed on top of the available public key infrastructures.

关键词： Elliptic curve signing group individual signer collective signature group signature

Constructing Collective Signature Schemes Using Problem of Finding Roots Modulo

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Computers, Materials & Continua 2022年第7期72卷 1105-1122页

Digital signature schemes are often built based on the difficulty of the discrete logarithm problems,of the problem of factor analysis,of the problem of finding the roots modulo of large primes or a combination of the difficult problems mentioned *** this paper,we use the new difficult problem,which is to find the wth root in the finite ground field GF(p)to build representative collective signature schemes,but the chosen modulo p has a special structure distinct p=Nt_(0)t_(1)t_(2)+1,where N is an even number and t_(0),t_(1),t_(2) are prime numbers of equal magnitude,about 80 *** characteristics of the proposed scheme are:i)The private key of each signer consists of 2 components(K_(1),K_(2)),randomly selected,but the public key has only one component(Y)calculated by the formula Y=K_(w)^(1)_(1) K^(w)_(2)^(2);w_(1)=t_(0)t_(1) and w_(2)=t_(0)t_(2);and ii)The generated signature consists of a set of 3 components(e,S_(1),S_(2)).We use the technique of hiding the signer’s public key Y,which is the coefficientλgenerated by the group nanager,in the process of forming the group signature and representative collective signature to enhance the privacy of all members of the signing collective.

关键词： Computing roots finding roots modulo collective signature signing collective signing group

New Representative Collective Signatures Based on the Discrete Logarithm Problem

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Computers, Materials & Continua 2022年第10期73卷 783-799页

The representative collective digital signature scheme allows the creation of a unique collective signature on document M that represents an entire signing community consisting of many individual signers and many different signing groups,each signing group is represented by a group *** document M,a collective signature can be created using the representative digital signature scheme that represents an entire community consisting of individual signers and signing groups,each of which is represented by a group *** characteristic of this type of letter is that it consists of three elements(U,E,S),one of which(U)is used to store the information of all the signers who participated in the formation of the collective signature on document *** storing this information is necessary to identify the signer and resolve disputes later,it greatly increases the size of *** is considered a limitation of the collective signature representing 3 *** this paper,we propose and build a new type of collective signature,a collective signature representing 2 elements(E,S).In this case,the signature has been reduced in size,but it contains all the information needed to identify the signer and resolve disputes if *** construct the approved group signature scheme,which is the basic scheme for the proposed representative collective signature schemes,we use the discrete logarithm problem on the prime finite *** the end of this paper,we present the security analysis of the AGDS scheme and a performance evaluation of the proposed collective signature schemes.

关键词： Elliptic curve signing group individual signer collective signature group signature

Constructing Representative Collective Signature Protocols Using The GOST R34.10-1994 Standard

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Computers, Materials & Continua 2023年第1期74卷 1475-1491页

作者： tuan Nguyen Kim Duy ho Ngoc Nikolay A.Moldovyan School of Computer Science Duy Tan UniversityDanangVietnam Department of Information Technology HanoiVietnam ITMO University St.PetersburgRussia

The representative collective digital signature,which was suggested by us,is built based on combining the advantages of group digital signature and collective digital *** collective digital signature schema helps to create a unique digital signature that deputizes a collective of people representing different groups of signers and may also include personal *** advantage of the proposed collective signature is that it can be built based on most of the well-known difficult problems such as the factor analysis,the discrete logarithm and finding modulo roots of large prime numbers and the current digital signature standards of the United States and Russian *** this paper,we use the discrete logarithmic problem on prime finite fields,which has been implemented in the GOST R34.10-1994 digital signature standard,to build the proposed collective signature *** protocols help to create collective signatures:Guaranteed internal integrity and fixed size,independent of the number of members involved in forming the *** signature built in this study,consisting of 3 components(U,R,S),stores the information of all relevant signers in the U components,thus tracking the signer and against the“disclaim of liability”of the signer later is *** idea of hiding the signer’s public key is also applied in the proposed *** makes it easy for the signing group representative to specify which members are authorized to participate in the signature creation process.

关键词： Signing collective signing group discrete logarithm group signature collective signature GOST standards

Regularization of the Inverse Problem for Time Fractional Pseudo-parabolic Equation with Non-local in Time Conditions

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Acta Mathematica Sinica,English Series 2022年第12期38卷 2199-2219页

作者： Nguyen Duc PHUONG le Dinh LONG Anh tuan NGUYEN Dumitru BAleANU Faculty of Fundamental Science Industrial University of Ho Chi Minh CityVietnam Division of Applied Mathematics Science and Technology Advanced InstituteVanLang UniversityHoChi Minh CityVietnam Faculty of Technology Van Lang UniversityHo Chi Minh CityVietnam Department of Mathematics Cankaya UniversityAnkaraTurkey lebanese AmericanUniversity BeirutLebanon Institute of Space Sciences Magurele-BucharestRomania

This paper is devoted to identifying an unknown source for a time-fractional diffusion equation in a general bounded ***,we prove the problem is non-well posed and the stability of the source ***,by using the Modified Fractional Landweber method,we present regularization solutions and show the convergence rate between regularization solutions and sought solution are given under a priori and a posteriori choice rules of the regularization parameter,***,we present an illustrative numerical example to test the results of our theory.

关键词： Source problem fractional pseudo-parabolic problem ill-posed problem convergence estimates regularization

Is convenience really king? Comparative evaluation of catastrophic costs due to tuberculosis in the public and private healthcare sectors of Viet Nam: a longitudinal patient cost study

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贫困所致传染病(英文) 2024年第2期13卷 1-12页

作者： Nguyen hoa Binh Quang Vo Luan Nguyen Forse Rachel Jeanette Wiemers Anja Maria Christine Huynh Huy Ba Dong Thuy Thi Thu Phan Yen Thi hoang Creswell Jacob Dang Thi Minh Ha Nguyen Lan Huu Shedrawy Jad L?nnroth Knut Nguyen tuan Dinh Van Dinh Luong Annerstedt Kristi Sidney Codlin Andrew James National Lung hospital Ha Noi Viet Nam Friends for International TB Relief Ha Noi Viet Nam Department of Global Public Health WHO Collaboration Centre On Tuberculosis and Social Medicine Karolinska Institute Stockholm Sweden Stop TB Partnership Geneva Switzerland Pham Ngoc Thach hospital Ho Chi Minh City Viet Nam

Background In Viet Nam, tuberculosis (TB) represents a devastating life-event with an exorbitant price tag, partly due to lost income from daily directly observed therapy in public sector care. Thus, persons with TB may seek care in the private sector for its flexibility, convenience, and privacy. Our study aimed to measure income changes, costs and catastrophic cost incurrence among TB-affected households in the public and private *** Between October 2020 and March 2022, we conducted 110 longitudinal patient cost interviews, among 50 patients privately treated for TB and 60 TB patients treated by the National TB Program (NTP) in Ha Noi, Hai Phong and ho Chi Minh City, Viet Nam. Using a local adaptation of the Who TB patient cost survey tool, participants were interviewed during the intensive phase, continuation phase and post-treatment. We compared income levels, direct and indirect treatment costs, catastrophic costs using Wilcoxon rank-sum and chi-squared tests and associated risk factors between the two cohorts using multivariate *** The pre-treatment median monthly household income was significantly higher in the private sector versus NTP cohort (USD 868 vs USD 578;P=0.010). however, private sector treatment was also significantly costlier (USD 2075 vs USD 1313;P=0.005), driven by direct medical costs which were 4.6 times higher than costs reported by NTP participants (USD 754 vs USD 164;Phorts (Private: 55% vs NTP: 52%;P=0.675). Factors associated with catastrophic cost included being a single-person household [adjusted odds ratio [(aOR=13.71; 95% confidence interval (CI): 1.36–138.14;P=0.026], unemployment during treatment (aOR=10.86; 95%CI: 2.64–44.60;P<0.001) and experiencing TB-related stigma (aOR=37.90; 95%CI: 1.72–831.73;P=0.021).Conclusions Persons with TB in Viet Nam face similarly high risk of catastrophic costs whether treated in the

关键词： Tuberculosis Patient cost Catastrophic cost Private sector Comparative analysis Viet Nam

Adaptive data fusion framework for modeling of non-uniform aerodynamic data

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Chinese Journal of Aeronautics 2023年第7期36卷 316-336页

作者： Vinh PHAM Maxim TYAN tuan Anh NGUYEN Chi-ho leE L.V.Thang NGUYEN Jae-Woo leE Department of Aerospace Information Engineering Konkuk UniversitySeoul 05029Republic of Korea Konkuk Aerospace Design-Airworthiness Institute Konkuk UniversitySeoul 05029Republic of Korea

Multi-fidelity Data Fusion(MDF)frameworks have emerged as a prominent approach to producing economical but accurate surrogate models for aerodynamic data modeling by integrating data with different fidelity ***,most existing MDF frameworks assume a uniform data structure between sampling data sources;thus,producing an accurate solution at the required level,for cases of non-uniform data structures is *** address this challenge,an Adaptive Multi-fidelity Data Fusion(AMDF)framework is proposed to produce a composite surrogate model which can efficiently model multi-fidelity data featuring non-uniform ***,the design space of the input data with non-uniform data structures is decomposed into subdomains containing simplified ***,different MDF frameworks and a rule-based selection process are adopted to construct multiple local models for the subdomain *** the other hand,the Enhanced Local Fidelity Modeling(ELFM)method is proposed to combine the generated local models into a unique and continuous global ***,the resulting model inherits the features of local models and approximates a complete database for the whole design *** validation of the proposed framework is performed to demonstrate its approximation capabilities in(A)four multi-dimensional analytical problems and(B)a practical engineering case study of constructing an F16C fighter aircraft’s aerodynamic *** comparisons of the generated models using the proposed AMDF framework and conventional MDF approaches using a single global modeling algorithm are performed to reveal the adaptability of the proposed approach for fusing multi-fidelity data featuring non-uniform ***,the results indicated that the proposed framework outperforms the state-of-the-art MDF approach in the cases of non-uniform data.

关键词： Aerodynamic modeling Data fusion Diverse data structure Multi-fidelity data Multi-fidelity surrogate modeling

Enrichment of hydrogen in product gas from a pilot-scale rice husk updraft gasification system

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Carbon Resources Conversion 2022年第3期5卷 231-239页

作者： Phan Dinh tuan le Minh Quan Vo Trang Nhi hoang Minh Huong le Thi Kim Phung Daolun Feng hochiminh City University of Natural Resources and Environment 236B Le Van Sy St.Tan Binh Dist.Ho Chi Minh City 70.000Viet Nam Applied Research Institute for Natural Resources Materialand Environment58/4 Tran Van Du St.Tan Binh Dist.Ho Chi Minh City 70.000Viet Nam hochiminh City University of Technology 268 Ly Thuong Kiet St.Dist.10Ho Chi Minh City 70.000Viet Nam Vietnam National University-ho Chi Minh(VNU-HCM) Linh Trung WardThu Duc CityHo Chi Minh CityViet Nam College of Marine Science and Engineering Shanghai Maritime UniversityShanghai 200135PR China

An updraft gasifier was employed to treat 3 kg of dried rice husk per batch with different types of gasifying agents such as air,steam/air,and air with dolomite catalyst addition at various operating *** H2 content,low heating value,and H2/CO ratio in syngas were compared to determine the most effective solution to enhance the H2 production from rice husk *** presence of dolomite in air gasification produced the highest H2 content in the product gas,up to 15.4 mol%,followed by 7.08 and 3.6 mol%when steam/air and air standalone were used as gasifying agents,*** higher low heating value of syngas 5.1 MJ/Nm3 was observed in catalytic air gasification compared to 3.6 MJ/Nm3 when steam was *** optimal operation condition was reported at an airflow rate of 3 m3/h and a catalyst mixing ratio of 15%.

关键词： Rice husk Enriched hydrogen syngas Dolomite Updraft gasifier