Assessment of factors influencing on the success of public-private partnerships infrastructure projects in Vietnam

The implementation of public-private partnerships has become one of the effective models of cooperation between the public and private sectors in the development of infrastructure in Vietnam. This model has been adopted in Vietnam for many years and is intended to help governments build infrastructure and provide an opportunity to reduce government debt profiles. This study aims to identify the most critical factors that could determine the success of these projects. A questionnaire was conducted based on the participants’ experience in the implementation of public-private partnerships projects and a total of 216 respondents were received. A regression analysis shows that six critical success factors, including factors relevant to public sector, factors relevant to private sector, factors relevant to selected process partnerships, factors relevant to risk management systems, factors relevant to project information, and factors relevant to natural environment. The findings indicated that the most effective development projects could be carried out via PPPs if the government could focus on these important factors in the implementation process. The results will influence political development towards PPP and guide partners in developing public-private partnerships projects

Beyond Certificates: 6G-ready Access Control for the Service-Based Architecture with Decentralized Identifiers and Verifiable Credentials

In 6G, mobile networks are poised to transition from monolithic structures owned and operated by single mobile network operators into multi-stakeholder networks where various parties contribute with infrastructure, resources, and services. This shift brings forth a critical challenge: Ensuring secure and trustful cross-domain access control. This paper introduces a novel technical concept and a prototype, outlining and implementing a 5G Service-based Architecture that utilizes Decentralized Identifiers and Verifiable Credentials to authenticate and authorize network functions among each other rather than relying on traditional X.509 certificates or OAuth2.0 access tokens. This decentralized approach to identity and permission management for network functions in 6G reduces the risk of a single point of failure associated with centralized public key infrastructures, unifies access control mechanisms, and paves the way for lesser complex and more trustful cross-domain key management for highly collaborative network functions of a future Service-based Architecture in 6G.Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

Delay factors in the construction of irrigation and hydropower projects in Vietnam

Irrigation and hydropower are among the most important sectors in the construction industry that propel the economic needs of a developing country like Vietnam. The construction of these projects often suffers from severe delays, leading to financial losses and other negative impacts on the economy. This paper aims to determine delay factors in the construction of these projects. Among many, 39 most important candidates of delay causes were identified from the literature review. Further surveys on project participants were conducted for the severity of these causes. An exploratory factor analysis was utilized to identify latent factors that cause delays in construction projects. The analysis result categorized a few groups of factors such as abnormal factors on the construction site (e.g., labor accidents, hydrology, water flow, extreme weather) and technical factors related to the construction contractor (e.g., unsuitable schedule, outdated construction technology, unprofessional workers) that have the greatest impact on the delay in construction of irrigation and hydropower projects in Vietnam. These findings contribute to the body of knowledge of project management and risk management, hence an improvement in the efficiency of the project sectors’ performance

Measurement of the Upper Tropospheric Density and Temperature Profiles in Hanoi Using a Raman Lidar

The nitrogen molecular density and temperature profiles of the upper troposphere are measured by a Raman lidar system in Hanoi over the range from 3 km to 19 km. The spatial and temporal resolutions of profiles are 60 m and 1h, respectively. The nitrogen molecular density profiles are directly calculated from the range-corrected lidar signal. The temperature profiles are derived from the molecular density profile based on the assumptions of the hydrostatic equilibrium, the ideal-gas law and a fixed nitrogen molecule ratio in the atmosphere. The results of our lidar measurements show good agreement with the MSISE-90 atmospheric model. The maximum errors of density and temperature measurements are 6% and 7%, respectively. We estimated the height of tropopause in Hanoi about 16 km from the derived temperature profile. The measured density and temperature profiles from this Raman lidar can be used for studying the trends and characteristics of the upper troposphere in Hanoi

Electrochemical DNA sensor for label-free soybean transgenic detection

This paper describes the development of electrochemical label- free DNA sensor for detection of transgenic in Round–up Ready Soybean (herbicide tolerance). Two pairs of electrodes which the optimized dimension is 70µm x 30µm (the width of electrode x inter-distance between fingers), were fabricated on a chip for differential measures. The DNA probe (35S 5’-GCT CCT ACA AAT GCC ATC A-3) was designed in such a way that it can hybridize with the CaMV 35S promoter of Roundup Ready soybean. The DNA was immobilized on the surface of the sensor by the mean of (3-aminopropyl)triethoxysilane (APTS) polymer. The response time of DNA sensor is less than 1 second; in case of 100% matching level, the sensitivity is 2 mV/µM. The activity of DNA sensor remains unchanged after 9 months of storage at -4oC in DI water. Some random soybean samples were collected, extracted and tested by the DNA sensor and the results were well matched with the of PCR method

Depolarization Property of Cirrus Clouds Over Hanoi

Cirrus cloud is one of the most commonly occurring cloud types globally. The clouds are found mainly to consist of floating ice crystals, which can reflect strongly incoming radiation. Lidar measurements provide an opportunity to study the microphysics and ice compositions of cirrus clouds. We have developed a polarization lidar system to measure the depolarization characteristics of the lower atmosphere over Hanoi. From our measurements of cirrus clouds over the period from 2010 to 2012, the depolarization ratio of cirrus clouds is found to be very high ranging from 20% up to 80{\%}, indicating large fraction of backscattering from ice crystals. We find a trend of increasing depolarization ratio with height and decreasing temperature. We also compare our lidar measurements with other results obtained by lidar technique in other regions of the world

Monitoring Cirrus Cloud and Tropopause Height over Hanoi Using a Compact Lidar System

Abstract. Cirrus clouds in the upper troposphere and the lower stratosphere have attracted great attention due to their important role and impact on the atmospheric radioactive balance. Because cirrus clouds are located high in the atmosphere, their study requires a high resolution remote sensing technique not only for detection but also for the characterization of their properties. The lidar technique with its inherent high sensitivity and resolution has become an indispensible tool for studying and improving our understanding of cirrus cloud. Using lidar technique we can simultaneously measure the cloud height, thickness and follow its temporal evolution. In this paper we describe the development of a compact and highly sensitive lidar system with the aim to remotely monitor for the first time the cirrus clouds over Hanoi (21001’42’’N, 105051’12’’W). From the lidar data collected during the year 2011. We derive the mean cloud height, location of cloud top, the cloud mean thickness and their temporal evolution. We then compare the location of the cloud top with the position of the tropopause determined the radiosonde data and found good that the distance between cloud top and tropopause remains fairly stable, indicating that generally the top of cirrus clouds is the good tracer of the tropopause. We found that the cirrus clouds are generally located at height between 11.2 to 15 km with average height of 13.4 km. Their thickness is between 0.3 and 3.8 km with average value of 1.7 km. We also compare the properties of cirrus cloud with that observed at other locations around the world based on lidar technique

Evaluation of Anterior Chamber Depth and Anterior Chamber Angle Changing After Phacoemulsification in the Primary Angle Close Suspect Eyes

BACKGROUND: Phacoemulsification surgery has the ability to deeply alter the segment anterior morphology, especially in eye with shallow anterior chamber (AC), narrow anterior chamber angle (ACA). However, the changes of anterior chamber depth (ACD) and ACA on the close angle suspect eyes after phacoemulsification have not been mentioned in many studies. So, we conduct this research. AIM: To evaluate the alteration in the ACA and ACD after phacoemulsification in the close angle suspect eyes. METHODS: Interventional study with no control group. Subjects were the primary angle closure suspect (PACS) eyes, that were operated by phacoemulsification with intraocular lens (IOL) at Glaucoma Department of VNIO from December 2017 to October 2018. RESULTS: 29 PACS eyes with cataract were operated by phacoemulsification with intraocular lens. After 3 months of monitoring, the average ACD augmented from 2.082 ± 0.244 to 3.673 ± 0.222 mm. AOD500 increase from 0.183 ± 0.088 to 0.388 ± 0.132 μm, AOD750 increased from 0.278 ± 0.105 to 0.576 ± 0.149 μm. The TISA500 enlarged from 0.068 ± 0.033 to 0.140 ± 0.052 mm2, TISA750 enlarged from 0.125 ± 0.052 to 0.256 ± 0.089 mm2 at the third month (p < 0.01). CONCLUSION: Phacoemulsification surgery increases the ACD and enlarged the angle in the PACS eyes