Cooperative Transmission Techniques in Wireless Communication Networks

Cooperative communication networks have received significant interests from both academia and industry in the past decade due to its ability to provide spatial diversity without the need of implementing multiple transmit and/or receive antennas at the end-user terminals. These new communication networks have inspired novel ideas and approaches to find out what and how performance improvement can be provided with cooperative communications. The objective of this thesis is to design and analyze various cooperative transmission techniques under the two common relaying signal processing methods, namely decode-and-forward (DF) and amplify-and-forward (AF). For the DF method, the thesis focuses on providing performance improvement by mitigating detection errors at the relay(s). In particular, the relaying action is implemented adaptively to reduce the phenomenon of error propagation: whether or not a relay’s decision to retransmit depends on its decision variable and a predefined threshold. First, under the scenario that unequal error protection is employed to transmit different information classes at the source, a relaying protocol in a singlerelay network is proposed and its error performance is evaluated. It is shown that by setting the optimal signal-to-noise ratio (SNR) thresholds at the relay for different information classes, the overall error performance can be significantly improved. Second, for multiple-relay networks, a relay selection protocol, also based on SNR thresholds, is proposed and the optimal thresholds are also provided. Third, an adaptive relaying protocol and a low-complexity receiver are proposed when binary frequency-shift-keying (FSK) modulation is employed and neither the receiver nor the transmitter knows the fading coefficients. It is demonstrated that large performance improvements are possible when the optimal thresholds are implemented at the relays and destination. Finally, under the scenario that there is information feedback from the destination to the relays, a novel protocol is developed to achieve the maximum transmission throughput over a multiple-relay network while the bit-error rate satisfies a given constraint. With the AF method, the thesis examines a fixed-gain multiple-relay network in which the channels are temporally-correlated Rayleigh flat fading. Developed is a general framework for maximum-ratio-combining detection when M-FSK modulation is used and no channel state information is available at the destination. In particular, an upper-bound expression on the system’s error performance is derived and used to verify that the system achieves the maximal diversity order. Simulation results demonstrate that the proposed scheme outperforms the existing schemes for the multiple-relay network under consideration

INVESTIGATION OF INFLUENCES OF FABRICATION TOLERANCES ON OPERATIONAL CHARACTERISTICS OF PIEZO-ACTUATED STICK-SLIP MICRO-DRIVES

Piezo-actuated stick-slip micro-drives (PASSMDs) are often used in microrobotic applications due to their advantages of a straightforward design and good operational characteristics. In this work, influences of fabrication tolerances on operational characteristics of PASSMDs are theoretically investigated. A dynamic model describing the whole macroscopic movement of the driver’s runner and the actuators, and the microscopic behavior of the frictional contacts using the method of dimensionality reduction, was used. Three essential parameters of the drives including the angle between working surfaces of the runner, the alignment angle between two actuator blocks on each side of the runner, and the stiffness of an individual actuator, whose values are impacted by the tolerance of the fabrication and assembly process, were considered as the input of the investigation. By performing hybrid-dynamic simulations, influences of these parameters on the drives' operational characteristics, including the repeatability of the step length, the critical amplitude phenomenon, and the maximal-achievable driving frequency/velocity, were evaluated. Simulation results show that these parameters significantly influence on the characteristics of the drives. The contribution of this work is so important that several important phenomena of PASSMDs, which are experimentally detected, are physically explained for the first time. The results of this work could help designers to optimize for better generations of PASSMDs

Case Study “XYZ Commercial Joint-Stock Bank”, Conversion of Financial Statements from Vietnam’s Accounting Standard into International Financing Reporting Standard

The aim of this study is to update significant differences between Vietnam’s accounting standards (VAS) and International financial report standards (IFRS). Case study “XYZ Commercial Joint-Stock Bank”, conversion of financial statements from VAS into IFRS. Analyzed the case study and status of conversion financial statements from VAS into IFRS of Vietnam listed Joint Stock Companies (JSCs) , author found and discussed impediments & challenges to convert IFRS financial statements in Vietnam and suggest to enhance roles of Vietnam Government and listed JSCs on the Vietnam stock market in an effort to convert and adopt IFRS financial statements as well as suggest to establish an IFRS conversion project to have an overview of  conversion processes financial statements from VAS into IFRS for Vietam listed JSCs Keywords: Conversion financial statement, International financial reporting standard, Vietnamese account standar

NEISKORIŠTENI POTENCIJAL I VISOKOTEHNOLOŠKA TRGOVINA: SLUČAJ IZVOZA ZEMALJA ASEAN-6

This study aims to quantify the impact of untapped export potential on ASEAN-6 countries’ high-tech exports for the 2006-2016 period. Our innovative aspect sheds new light on the relationship between the untapped export potential in the previous year and export performance in the current year. Using a system GMM estimator, we found several significant results. Firstly, untapped export potential in the last year has a positive impact on ASEAN-6 countries’ high-tech exports in the current year. Secondly, the effect of untapped export potential on ASEAN-6 countries’ high-tech exports depends on supply competencies (ASEAN-6 countries’ human capital and research and development capability) and the bilateral linkage (importing countries’ trade barriers and institutional similarity between ASEAN-6 countries and importing countries). Thirdly, supply competencies are the most important when ASEAN-6 countries export high-tech goods to high-income countries. In contrast, the bilateral linkage is the most crucial when ASEAN-6 countries ship high-tech products to low-income countries. Measures to enhance human capital, upgrade research and development capability, promote trade liberalization, and minimize the institutional distance with the trading partners are the remedy for ASEAN-6 countries to tap the untapped potential.Ova studija ima za cilj kvantificirati utjecaj neiskorištenog izvoznog potencijala na visokotehnološki izvoz zemalja ASEAN-6 za razdoblje 2006.-2016. Naš inovativni aspekt baca novo svjetlo na odnos između neiskorištenog izvoznog potencijala u prethodnoj godini i izvoznih rezultata u tekućoj godini. Koristeći sustav GMM procjenitelja, pronašli smo nekoliko značajnih rezultata. Prvo, neiskorišteni izvozni potencijal u prošloj godini ima pozitivan učinak na visokotehnološki izvoz zemalja ASEAN-6 u tekućoj godini. Drugo, učinak neiskorištenog izvoznog potencijala na visokotehnološki izvoz zemalja ASEAN-6 ovisi o opskrbnim kompetencijama (ljudski kapital i sposobnost istraživanja i razvoja u zemljama ASEAN-6) i bilateralnoj povezanosti (trgovinske prepreke zemalja uvoznica i institucionalna sličnost između zemlje ASEAN-6 i zemlje uvoznice). Treće, kompetencije u opskrbi su najvažnije kada zemlje ASEAN-6 izvoze robu visoke tehnologije u zemlje s visokim dohotkom. Nasuprot tome, bilateralna veza je najvažnija kada zemlje ASEAN-6 isporučuju visokotehnološke proizvode u zemlje s niskim prihodima. Mjere za poboljšanje ljudskog kapitala, nadogradnju istraživačkih i razvojnih sposobnosti, promicanje liberalizacije trgovine i smanjenje institucionalne udaljenosti s trgovinskim partnerima, lijek su za zemlje ASEAN-6 da iskoriste neiskorišteni potencijal

Analysis of rDNA reveals a high genetic diversity of Halophila major in the Wallacea region

The genus Halophila shows the highest species diversity within the seagrass genera. Southeast Asian countries where several boundary lines exist were considered as the origin of seagrasses. We hypothesize that the boundary lines, such as Wallace’s and Lydekker’s Lines, may act as marine geographic barriers to the population structure of Halophila major. Seagrass samples were collected at three islands in Vietnamese waters and analyzed by the molecular maker ITS. These sequences were compared with published ITS sequences from seagrasses collected in the whole region of interest. In this study, we reveal the haplotype and nucleotide diversity, linking population genetics, phylogeography, phylogenetics and estimation of relative divergence times of H. major and other members of the Halophila genus. The morphological characters show variation. The results of the ITS marker analysis reveal smaller groups of H. major from Myanmar, Shoalwater Bay (Australia) and Okinawa (Japan) with high supporting values. The remaining groups including Sri Lanka, Viet Nam, the Philippines, Thailand, Malaysia, Indonesia, Two Peoples Bay (Australia) and Tokushima (Japan) showed low supporting values. The Wallacea region shows the highest haplotype and also nucleotide diversity. Non-significant differences were found among regions, but significant differences were presented among populations. The relative divergence times between some members of section Halophila were estimated 2.15–6.64 Mya

Role of GmNAC019 transcription factor in salinity and drought tolerance of transgenic Arabidopsis thaliana

Increasingly severe drought and salinity stress due to global climate change have made these stresses bigger threats to ecosystem and agriculture. Previous studies reported that GmNAC019, a soybean NAC transcription factor - encoding gene, displayed induced expression upon drought treatment in wild-type cultivars. In this study, drought and salinity stresses were applied on GmNAC019-overexpressing Arabidopsis plants to verify the contribution of GmNAC019 in regulating plant response to the stress conditions. Results from the water loss rate and survival rate assays revealed that the transgenic line conferred improved tolerance to drought stress as evidenced by lower leaf water loss and significantly higher rate of survival than seen in the wild-type plants. Similarly, the survival rate assay for testing salinity effects on plants by growing the plants on MS medium supplemented with different NaCl concentrations also indicated that the transgenic plants had a better tolerance to salt stress as they displayed lower rate of root growth inhibition and higher survival rate. Taken these results altogether, it is suggested that GmNAC019 might play important role in aiding plant response to drought and salinity stresses. Specific functions of this gene should be elaborated in future studies to evaluate its potential application for crop improvement

Driving Factors for Green Innovation in Vietnamese Construction Enterprises

Purpose: The aim of this study is to examine the influences of different factors on green innovation in Vietnamese construction enterprises.   Theoretical framework: The theoretical framework is built upon the resource-based view, the model of organizational innovation, and stakeholder theory.   Design/methodology/approach: The research carries out a literature survey related to construction enterprises, then empirical analysis is conducted among 450 employees and managers at all level working in this field with the results analyzed using Cronbach’s Alpha analysis, exploratory factor analysis, pearson correlation analysis, linear regression analysis and One - way ANOVA analysis.   Findings: The results demonstrate that using renewable energy is well represented for green innovation in the Vietnamese construction industry and quantitative results also show positive impacts of all factors studied on green innovation: Green dynamic capabilities, Green creativity, Green knowledge sharing, Corporate environmental ethics, Pressure from industry competitors and regulators. In addition, the result affirmed there are statistically significant differences in the level of green innovation between construction enterprises of size and age, but not types of firm.   Research, Practical & Social implications: The study proposes solutions for both enterprises and regulators – one of the external stakeholders to develop green innovation in the construction sector. 

Economic Instruments and the Pollution Impact of the 2006-2010 Vietnam Socio-Economic Development Plan

The current study derives optimal growth paths for pollution emission charges, in order to control future water pollution emissions in the Vietnamese manufacturing sector. The study builds on a prior study, which estimated the manufacturing sector pollution impact of the 2006- 2010 SEDP development plan for Vietnam (Jensen et al.; 2008). The current study demonstrates that effective implementation and moderate expansion of optimal emission charges, under certain conditions, could have been used, as part of the 2006-2010 SEDP development plan, to control pollution emissions at 2005 levels. Moreover, such a scenario would have been accompanied by a moderate expansion in fiscal revenues and a relatively minor economy-wide efficiency loss. The current study, therefore, suggests that effective implementation and gradual expansion of pollution emission charges should be incorporated into future SEDP development plans, in order to control pollution emissions as development progresses in Vietnam.Vietnam, manufacturing, CGE