Geometric Perspective on Kinematics and Singularities of Spatial Mechanisms

This doctoral dissertation deals with the kinematics and singularity analyses of serial and parallel manipulators with multiple working modes. The inverse kinematics of 6R architectures with non-spherical wrists were solved using simple geometric considerations; the problem was reduced to the solution of a trigonometric equation in one variable, the sixth joint angle. The direct kinematic analysis of the parallel manipulator, namely the Exechon, was conducted; it involves using a standard numerical tool to solve the system of equations in platform\u2019s angle variables. Both kinematics analyses took advantage of the standard numerical solver to obtain the solutions. The singularities of the Exechon were studied with the geometrical interpretation. By using the theory of reciprocal screws, the input-output velocity equations were introduced. This led to the investigation of the Jacobian matrices, which is an essential part when working with any manipulator. A method for obtaining the singularity loci and the numerical example was provided. The formulations presented in this dissertation are general and effective enough to be applicable for many other similar architectures

A New Approach to Keep the Privacy Information of the Signer in a Digital Signature Scheme

In modern applications, such as Electronic Voting, e-Health, e-Cash, there is a need that the validity of a signature should be verified by only one responsible person. This is opposite to the traditional digital signature scheme where anybody can verify a signature. There have been several solutions for this problem, the first one is we combine a signature scheme with an encryption scheme; the second one is to use the group signature; and the last one is to use the strong designated verifier signature scheme with the undeniable property. In this paper, we extend the traditional digital signature scheme to propose a new solution for the aforementioned problem. Our extension is in the sense that only a designated verifier (responsible person) can verify a signer’s signature, and if necessary (in case the signer refuses to admit his/her signature) the designated verifier without revealing his/her secret key is able to prove to anybody that the signer has actually generated the signature. The comparison between our proposed solution and the three existing solutions shows that our proposed solution is the best one in terms of both security and efficiency

THE APPLICATION OF GENERAL ENDURANCE EXERCISES TO IMPROVE 3000-METER ARMED RUNS OF MALE MILITIA FORCES AGED 25-28 IN HO CHI MINH CITY, VIETNAM

A 3000-meter run with guns, a common physical exercise to train endurance in military force, is one of the training and competition contents for male soldiers of the Vietnam People's Armed Forces in general and militia forces in particular. The purpose of this study was to build up a general endurance exercise for male militia forces aged 25-28 in Ho Chi Minh City. Independent samples t-test was used to compare the difference between the experimental and control groups, while Paired sample t-test was used to identify the difference between the pre- and post-experimental. By using the general methods in sport, 12 general endurance exercises were selected and applied for male militia forces in 3000-meter armed runs. Besides, the result showed that there was a significant difference between the two groups (the experimental group had higher scores when compared with the control one) after eight weeks of training.  Article visualizations

Private Ciphertext-Policy Attribute-based Encryption Schemes With Constant-Size Ciphertext Supporting CNF Access Policy

Attribute-based encryption (ABE) is an extension of traditional public key encryption in which the encryption and decryption phases are based on user\u27s attributes. More precisely, we focus on cipher-text-policy ABE (CP-ABE) where the secret-key is associated to a set of attributes and the ciphertext is generated with an access policy. It then becomes feasible to decrypt a ciphertext only if one\u27s attributes satisfy the used access policy. In this paper, we give the first private CP-ABE constructions with a constant-size ciphertext, supporting CNF (Conjunctive Normal Form) access policy, with the simple restriction that each attribute can only appear $k_{max}$ times in the access formula. Our two constructions are based on the BGW scheme at Crypto\u2705. The first scheme is basic selective secure (in the standard model) while our second one reaches the selective CCA security (in the random oracle model)

Anti-inflammatory activity of methyl ferulate isolated from Stemona tuberosa Lour

AbstractObjectiveTo evaluate the anti-inflammatory activity of methyl ferulate (MF) isolated from the roots of Stemona tuberosa (S. tuberosa) Lour (Stemonaceae) in lipopolysaccharide activated macrophage cells.MethodsMethanol extracts of a root powder of S. tuberosa were prepared for isolation of a potential anti-inflammatory agent using ultrasound extraction combined with repeated chromatography on silica gel. After the quantitative analyses, anti-inflammatory activity of the isolated compound was evaluated by measurement of cytokine release, NO generation, expression of cyclooxygenase-2 and phosphorylation of mitogen activated protein kinases including p38 and c-Jun NH2-terminal kinase using quantitative kits and Western blotting with specific antibodies.ResultsThe isolation process yielded a potential anti-inflammatory compound with a purity level of 99% determined by high performance liquid chromatography. The compound was identified as MF by using nuclear magnetic resonance. MF strongly inhibited the release of pro-inflammatory cytokines from macrophages, including IL-6, TNFα, IFNγ, yet it did not affect the anti-inflammatory cytokine IL-10. Phosphorylation of p38 and c-Jun NH2-terminal kinase were clearly reduced in MF-treated macrophages stimulated with lipopolysaccharide. cyclooxygenase-2 expression and NO generation by macrophages were also suppressed when the cells were treated with MF.ConclusionsThe data suggested that MF is a possible inhibitor of the mitogen activated phosphor kinase pathway and could be a potential anti-inflammatory agent isolated for the first time in medicinal plant S. tuberosa

Resistance to Pirates 2.0: A Method from Leakage Resilient Cryptography

In the classical model of traitor tracing, one assumes that a traitor contributes its entire secret key to build a pirate decoder. However, new practical scenarios of pirate has been considered, namely Pirate Evolution Attacks at Crypto 2007 and Pirates 2.0 at Eurocrypt 2009, in which pirate decoders could be built from sub-keys of users. The key notion in Pirates 2.0 is the anonymity level of traitors: they can rest assured to remain anonymous when each of them only contributes a very small fraction of its secret information. This scenario encourages dishonest users to participate in collusion and the size of collusion could become very large, possibly beyond the considered threshold in the classical model. There are numerous attempts to deal with Pirates 2.0 each of which only considers a particular form of Pirates 2.0. In this paper, we propose a method for fighting Pirates 2.0 in any form. Our method is based on the researches in key-leakage resilience. It thus gives an interesting and rather surprised connection between the rich domain of key-leakage resilient cryptography and Pirates 2.0. We first formalize the notion of key-leakage resilient revoke system and then identify sufficient conditions so that a key-leakage resilient revoke scheme can resist Pirates 2.0 in any form. We finally propose a construction of a secure key-leakage resilient identity-based revoke system that fulfills the required conditions. The main ingredient in the construction relies on the identity-based encryption with wildcards (\WIBE) and our construction of key-leakage resilient \WIBE could be useful in its own right

Biomolecular evaluation of three contrasting rice cultivars (Oryza sativa L.) in salt stress response at seedling stage.

Salt contamination of soils due to climate change faces a severe environmental issue that affects crop production today. However, the response mechanism in plants to salt stress is not fully understood. The present study investigated molecular and biochemical changes under salt stress in rice seedlings of three rice cultivars, i.e., AGPPS114 (salt-tolerant), OM6967 (moderately tolerance), VD20 (salt-sensitive). Increasing salt concentration leads to a reduction in shoot/root length but different levels among the cultivars. In contrast, reactive oxygen species (ROS) accumulation and lipid peroxidation increased progressively with increasing salt concentration and time course treatment. However, at 250 ?M of NaCl, these parameters were more adversely affected in VD20 than AGPPS114 and OM6967. Using ICP showed that Na+ accumulation in rice root increased gradually with increasing NaCl concentrations in all cultivars under salt treatment but was low in salt-sensitive cultivar VD20 compared to other cultivars. Antioxidant enzyme activity analysis indicated catalase (CAT) and superoxide dismutase (SOD) were induced during salt treatment in all cultivars. The results also showed greater proline and glycine betaine accumulation in the AGPPS114 than OM6976 and VD20. qPCR indicated a significant difference in transcript levels of the Na+-transporter gene OsSOS1, OsNHX1 and OsHKT1s in AGPPS114 and OM6967 cultivars compared to VD20 cultivar. In summary, the active regulation of genes related to Na+ transport at the transcription level and with high glycine betaine and proline accumulation levels may be involved in salt tolerance mechanisms and thus might be useful for selecting tolerant plants

The Impact of Job Satisfaction on Job Performance of Tax Officials: An Empirical Study in Vietnam

Purpose: The level of employee satisfaction with the use of e-tax systems is a major factor influencing the success of such systems. While studies typically focus on taxpayers' perspectives, this research investigates the influence of perceived ease of use, IT background, incentives, and social influence on tax officials’ job performance, mediated by tax officials’ job satisfaction.   Theoretical framework: The research is based on the Theory of Planned Behavior (TPB) and Technology Acceptance Model (TAM) to propose the research model which analyze the impact of job satisfaction on job performance.    Design/Methodology/Approach: A quantitative approach was adopted, involving surveys administered to tax officials in Vietnam. The study analyzed 250 valid responses using Cronbach's test, Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA), and Structural Equation Modeling (SEM).   Findings: The research revealed that all four factors significantly influence job performance through job satisfaction of tax officials in Vietnam. These findings provide valuable insights for tax authorities to improve job performance.   Research, Practical & Social implications: The research results contribute to other countries with similar characteristics in devising strategies to enhance employee performance. However, its limitations include its generalizability to other e-tax systems and countries. Future research with a larger sample size could bolster the applicability of these findings nationally.   Originality/Value: The research suggests tax authorities to support tax officials improve their professional skills; improve the regulations, policies on salary and bonus for tax officials; assist tax officials in using the e-tax system; implement effective communication

Phase Shift Design for RIS-Aided Cell-Free Massive MIMO with Improved Differential Evolution

This paper proposes a novel phase shift design for cell-free massive multiple-input and multiple-output (MIMO) systems assisted by reconfigurable intelligent surface (RIS), which only utilizes channel statistics to achieve the uplink sum ergodic throughput maximization under spatial channel correlations. Due to the non-convexity and the scale of the derived optimization problem, we develop an improved version of the differential evolution (DE) algorithm. The proposed scheme is capable of providing high-quality solutions within reasonable computing time. Numerical results demonstrate superior improvements of the proposed phase shift designs over the other benchmarks, particularly in scenarios where direct links are highly probable.Comment: 5 pages, 2 figures. Accepted by IEEE WC

Identity and community structure in Neolithic Man Bac, Northern Vietnam

FUNDING This research was supported by JSPS fund 16H02527 and Australian Research Council grant DP0774079. ACKNOWLEDGEMENTS Many people have been involved in the excavation and post-excavation work associated with Man Bac over the years. Here we wish to pay special thanks to Nguyen Kim Dung (then of the Institute of Archaeology, Hanoi) who co-directed the excavations in 2004/5 and 2007. The following were involved in either one or several ways between 2004/5 and 2007 (facilitation of land access, excavation, post-excavation analysis, and ublication): Nguyen Hann Khang and Nguyen Cao Tan (Ninh Binh Provincial Museum, Vietnam), the landowner of Man Bac Nguyen Van Sai, the Chung Village community, Peter Bellwood and Lorna Tilley (Australian National University), Nguyen Giang Hai (former Director, Institute of Archaeology, Hanoi), Nguyen Kim Thuy, Nguyen An Tuan, Vu The Long, Tran Thi Thuy Ha, Bui Thu Phuong, Ha Manh Thang, Nguyen Ngoc Quy, Vo Thanh Huong, Nguyen Chi Tan, Nguyen Thi Mai Huong (Institute of Archaeology, Hanoi), Mariko Yamagata (Okayama Science University, Japan), Ken-ichi Shidoda (National Museum of Nature and Science, Japan), Yukio Dodo (formerly of Tohoku University, Japan), Takeji Toizumi (Meiji University, Japan), Junmei Sawada (Nigata University of Health and Welfare, Japan), Mark Lipson (Harvard Medical School, USA), Anna Willis (James Cook University, Australia). Many thanks to Jeff Oliver for reading and commenting on an earlier draft.Peer reviewedPostprin