Spanning Cacti for Structurally Controllable Networks

Master'sMASTER OF SCIENC

Transfer AdaBoost SVM for Link Prediction in Newly Signed Social Networks using Explicit and PNR Features

AbstractIn signed social network, the user-generated content and interactions have overtaken the web. Questions of whom and what to trust has become increasingly important. We must have methods which predict the signs of links in the social network to solve this problem. We study signed social networks with positive links (friendship, fan, like, etc) and negative links (opposition, anti-fan, dislike, etc). Specifically, we focus how to effectively predict positive and negative links in newly signed social networks. With SVM model, the small amount of edge sign information in newly signed network is not adequate to train a good classifier. In this paper, we introduce an effective solution to this problem. We present a novel transfer learning framework is called Transfer AdaBoost with SVM (TAS) which extends boosting-based learning algorithms and incorporates properly designed RBFSVM (SVM with the RBF kernel) component classifiers. With our framework, we use explicit topological features and Positive Negative Ratio (PNR) features which are based on decision-making theory. Experimental results on three networks (Epinions, Slashdot and Wiki) demonstrate our method that can improve the prediction accuracy by 40% over baseline methods. Additionally, our method has faster performance time

Application of HEC-HMS model and satellite precipitation products to restore runoff in Laigiang river basin in Vietnam

The Laigiang river basin in the South Central Coast of Vietnam plays an important role in the socio-economic development of Binhdinh Province. In recent decades, the region has experienced commonly flooding in vast areas. This research aims to simulate event-based rainfall-runoff modelling, a historical flood event in December 2016, by applying the HEC-HMS model and rainfall data from CHIRPS. The CHIRPS data is an acceptable potential data input of the hydrology model. These have been confirmed through reliable validation indexes: The peak flood flow rate of 2,542.6 m3/s corresponds to the flood frequency of 5%; NSE with the value at 0.95; R2 coefficient reached 0.87; PBIAS being around 0.45, and PFC being at 0.89. It shows better performance in the rainy season than in the dry season. Inclusive, the CHIRPS rainfall data set and the HEC model could be used for some operational purposes in weather forecasting, especially for flood warnings in river basins in the South Central Coast, Vietnam

Beads excavated from Antsiraka Boira necropolis (Mayotte Island, 12th-13th centuries)

About hundred out of three hundred colored beads excavated from the necropolis of Antsiraka Boira (AB), in Mayotte Island (12-13th c.) were classified according to Wood’s morphological criteria and studied with a portable Raman spectrometer (532nm). Based on the recorded spectra, 22 beads were identified as representative and further analyzed in the laboratory with High-Resolution Raman spectrometers, using wavelengths of 458, 633 and 785nm. Additional SEM-EDS analysis was carried out on the surface and, sometimes, the bead cross-section. It turns out that white beads are made of aragonite and that almost all other beads have a soda glass matrix. Pyrochlore (yellow), amber/“Fe-S” (black), manganese oxide (black), copper metal nanoparticles (red), and Cu2+ ions (turquoise) chromophores were identified. Some red, yellow, black and turquoise beads also show the signature of chromium-doped tin sphene that could therefore be used as a marker. Most beads from the AB site can be classified as “Indo-Pacific”, revealing a similarity with the contemporary South African site of K2 (close to Mapungubwe). However, some red and black beads are similar to molten ceramic beads from the Vohemar Islamic necropolis (13-17th century AD, Madagascar Island). The on-site Raman analysis appears sufficient for the identification of chromophores and glass types.Un ensemble d’une centaine de perles de la nécropole d’Antsiraka Boira (AB), Mayotte (xiie-xiiie siècles), considérées comme représentatives d’un lot de ~300, a été classé selon le système morphologique de Wood et analysé par spectroscopie Raman portable (532 nm). 22 perles représentatives ont été analysées par Raman avec différentes excitations laser (458, 633 et 785 nm) et SEM-EDS en surface, ou pour certaines sur section. Les chromophores ont été identifiés : pyrochlore (jaune), ambre/Fe-S  (noir), oxyde de manganèse (noir), Cu0 metal nanoparticules (rouge) et Cu2+ ions (turquoise). Les perles blanches sont en aragonite (CaCO3). Quelques perles rouges, jaunes, noires et une perle turquoise contiennent aussi le chromophore Cr-Sn sphène. Sa signature Raman, inattendue, pourra servir de marqueur. La quasi-totalité des matrices vitreuses sont sodiques. La comparaison des perles d’AB avec celles des sites de Mapungubwe/K2 (Afrique du Sud), met en évidence l’homogénéité du corpus comme pour K2, site contemporain de Antsiraka Boira et aussi classé « Indo-Pacifique ». Certaines perles rouges et noires, sont plus proches d’une céramique fondue que d’un verre, à l’instar de perles de Vohémar (xiiie-xviie siècle, Madagascar). L’analyse au spectromètre Raman portable apparait suffisante pour identifier chromophores et types de verre

Student Satisfaction with Quality of Accounting and Auditing Education: The Case of Vietnam

This research is conducted to examine and evaluate determinants influencing the level of student satisfaction in the quality of auditing and accounting training at Vietnamese universities. Data were collected from 213 students of accounting and auditing field in three universities of National Economics University, University of Commerce and Academy of Finance. Exploratory factor analysis (EFA) and linear regression models were employed to determine the determinants influencing student satisfaction about quality of accounting and auditing. The findings show that the strongest impact on student satisfaction was the ability to serve; then training program; infrastructure component, and the last of teaching team. Based on the results, some recommendations are proposed for improving the satisfaction levels of students of accounting and auditing. Keywords: Quality of service; Quality of training; Satisfactio

Some study results of Cam Ranh - Binh Thuan mud eruption strip

Most of the mud eruption locations are distributed in a stretching strip, running in NE-SW direction from Cam Ranh - Ninh Thuan - Binh Thuan NE-SW tectonic fault zone and coinciding with a tectonically crushed zone. The erupted mud consists of sand, mud, clay. The clay contains alkaline montmorillonite, formed following chemical weathering and re-sedimentation processes from rocks containing alkaline minerals in a semi-arid climate area, located in a low terrain or a tectonic subsiding zone with a large fluctuation in groundwater level. The mud eruption  has a close relation to factors (of) climate, topography, geomorphology, hydrogeology, petrography and tectonic activities in the area. Among these, tectonic factors are the most important for they create not only soil and rock crushed zone, paving favorable conditions for strong weathering process at depth, but also to form canals to bring hot groundwater and minerals from certain depths upward, and by the effects of pressurized groundwater and partly due to the expansion in volume of bentonite clay pushing the muddy clay material through the tectonic cracks to the surface of the current terrain. The mud eruption process is not deep; but it may occur from a shallow level, about 4-18 m below, under the impact of the above elements.ReferencesCao Dinh Trieu, 2006. Characteristics of Earthquake Activities of Central Southern and Southern Sea.  Journal of Geology, Range A, 293(3-4), Hanoi.   Cao Dinh Trieu, et al., 2013. Modern geodynamics in Vietnamese territory. Natural Sciences and Technology Publishing House, Hanoi, 242.Ho Vuong Binh, et al., 1990. Research report on evaluation of prospects and possibility of using alkaline bentonite at Thuan Hai. Archived at the Center for Information Archives of Geology, Hanoi.Le Duc An, 1990. Geomorphological and neotectonic features of Thuan Hai area. Geological Science and Technique Information, (1-2), 5-25, Hanoi.Le Duy Bach, et al., 2007. Tectonic features Pliocene - Quaternary at Southeast continental shelf of Vietnam. Journal of Sciences of the Earth, 29(3), 218-227, Hanoi.Mazzini. A, A. Nermoen, M. Krotkiewski, Y. Podladchikov, S. Planke, H. Svensen, 2009. Strike-slip faulting as a trigger mechanism for overpressure release through piercement structures. Implications for the Lusi mud eruption, Indonesia. Marine and Petroleum Geology, doi:10.1016/j.marpetgeo.2009.03.001Medialdea. T, et al., 2003. Tectonics and mud eruption  development in the Gulf of Cadiz.  Marine Geology, 261(1-4), 48-63.Nguyen Duc Thai, et al., 2011. Report on survey results of land crack and mud appearance locations at Suoi Da village, Loi Hai commune, Thuan Bac district, Ninh Thuan province. Archived at Division for Water Resources Planning and Investigation for the Central Region of Vietnam.Nguyen Duc Thang (chief author) et al., 1988. Report on surveying and mapping of Geology and Minerals in Phan Rang-Nha Trang area at 1:200,000 scale. Archived at the Center for Information Archives of Geology, Hanoi.Nguyen Hong Phuong, 2004. Map of earthquake dangerous rate in Vietnam and the East Sea. Journal of Sciences of the Earth,  26(2), 97-111, Hanoi.Pham Van An, et al., 1990. Features of weathering crust at dry hot area Thuan Hai and origin of alkaline bentonite clay. Geological Science and Technique Information, (1-2), 72-79, Hanoi.Pham Van Hung, 2000. Determining kinematic properties of cracks by analyzing tectonic cracks in the South Central region, Journal of Sciences of the Earth, 29(2), 113-119, (in Vietnamese).Pham Van Hung, 2001. Quaternary - modern operational features of tectonic fault at the East edge of Kon Tum massif. Journal of Geology, 267, 43-49, Hanoi.Pham Van Nam, et al., 1988. Report on hydrogeological-engineering geological Mapping at 1:200,000 scale in Phan Rang-Nha Trang region. Archived at Division for Water Resources Planning and Investigation for the Central Region of Vietnam, Nha Trang.Phan Trong Trinh, 2012. Recent tectonics and modern geodynamics in Vietnam’s Sea and adjacent zones. Natural Sciences and Technology Publishing House, Hanoi, 331p.Pham Van Thuc, et al., 2004. Seismic zoning of the East Sea and coastal area in Vietnam. Journal of Geology, Range A, 285(11-12), Hanoi.Phung Van Phach, et al., 1996. Some research results of gases ash eruption phenomenon at Pleiku Highland in 1993. Geological Resources, 1, Science and Technique Publishing House, 396-405.Quo-Cheng Sung, Hung-Cheng Chang, HSing-Chang Liu, Yen-Chieh Chen, 2010. Mud eruption along the chihan fault in Southwestern Taiwan Arelease bend model. Geomorphology, 118, 188-198.Tran Van Thang, et al., 2006. Tectonic development characteristics of Da Lat zone and adjacent zone in late Mezozoi-Kainozoi. Journal of Sciences of the Earth, 28(2), 140-149, (in Vietnamese)..Stepanek P., Ho Trong Ty, 1986. Report on mineral geological mapping at Phan Rang-Cam Ranh at 1:50,000 scale. Archived at the Center for Information Archives of Geology, Hanoi.Vo Cong Nghiep, et al., 1998. List of hot water and minerals resources in Vietnam. Ministry of Industry, General Department of Geology and Minerals of Vietnam, Hanoi. 308p.Uong Dinh Khanh, 2004. Geomorphological characteristics of the hilly areas Ninh Thuan - Binh Thuan. Doctorate thesis, archived at National Library, Hanoi.Yin. P, S. Bern, P. Vagner, B. Loubrieu, Z. Liu, 2003. Mud eruption at the shelf margin of the East China Sea. Marine Geology, 194(3-4), 135-149.http://www.mhc.vn/. Minh Ha Bentonite Minerals JSC. 

KHẢ NĂNG LƯU TRỮ CACBON CỦA THẢM CỎ BIỂN TẠI ĐẦM LĂNG CÔ, TỈNH THỪA THIÊN HUẾ

Seagrass beds play an essential role in mitigating climate change by absorbing CO2 from the atmosphere and converting carbon into biomass through photosynthesis. We used remote sensing and GIS technology with field survey data to establish the distribution and above-ground dry biomass maps of seagrass beds in 2021. A Landsat 8 OLI satellite image was used in the interpretation process. An above-ground dry biomass map was established by building the regression function between the above-ground dry biomass and the reflectance spectrum of the image bands. The overall accuracy and the Kappa coefficient of the classification process were 95.5% and 0.94. At Lang Co Lagoon, the seagrass bed area in 2021 was about 36.18 ha, distributed primarily in the area between Lang Co Town and the north of the lagoon; and scattered in the north of the lagoon, Hoi Can, Hoi Dua, and Hoi Mit. In addition, the total carbon stock of seagrasses in Lang Co Lagoon was estimated at 5.54 tons, equivalent to 20.32 tons of CO2, in which the contribution of Halodule uninervis accounted for 61% of the total carbon stock.Thảm cỏ biển đóng vai trò quan trọng trong việc giảm thiểu biến đổi khí hậu thông qua việc hấp thụ CO2 từ khí quyển và chuyển cacbon thành sinh khối nhờ quá trình quang hợp. Chúng tôi đã sử dụng công nghệ viễn thám và GIS, kết hợp với dữ liệu khảo sát thực địa, để thành lập bản đồ phân bố và sinh khối khô trên mặt đất của hệ sinh thái thảm cỏ biển tại Đầm Lăng Cô vào năm 2021. Một ảnh vệ tinh Landsat 8 OLI đã được sử dụng trong quá trình giải đoán. Một bản đồ sinh khối khô trên mặt đất được thành lập thông qua việc xây dựng hàm hồi quy giữa sinh khối khô trên mặt đất và phổ phản xạ của các kênh ảnh Landsat. Độ chính xác tổng thể và hệ số Kappa là 95,5% và 0,94. Tại Đầm Lăng Cô, diện tích thảm cỏ biển năm 2021 chiếm khoảng 36,18 ha, phân bố chủ yếu ở các khu vực giao giữa Thị trấn Lăng Cô và phía Bắc của đầm; rải rác tại phía Bắc của đầm, Hói Cạn, Hói Dừa và Hói Mít. Ngoài ra, tổng trữ lượng cacbon của cỏ biển ở Đầm Lăng Cô là 5,54 tấn cacbon, tương đương với 20,32 tấn CO2; trong đó, sự đóng góp của loài Halodule uninervis chiếm 61% tổng trữ lượng cacbon

Towards refining the classification of glass trade beads imported into Southern Africa from the 8th to the 16th century AD

Tracing the origin of glass trade beads excavated at archaeological sites can contribute significantly to dating a site and reconstructing prehistoric trade routes. Wood developed a temporally sensitive bead sequence dating from the 8th to the 16th century AD for beads excavated at southern African sites that is commonly used by archaeologists to classify beads according to their morphology. In this study we develop a multidisciplinary methodology to refine the classification of glass beads based on morphology alone. Glass trade beads excavated at 11 sites along the upper reaches of the Limpopo River in east-central Botswana are used as case study. The beads were visually classified according to their morphological properties (colour, size, etc.) and analysed with Raman spectroscopy and portable X-ray fluorescence (XRF). Energy Dispersive Spectroscopy (EDS) of one bead showed that two types of glass were sintered together to form a recycled product, explaining the divergence of Raman spectra recorded on different zones. The study confirms the value of a morphological classification based on existing data sets as a first approach, but demonstrates that both Raman and XRF measurements can contribute to a more exact classification of glass beads imported into southern Africa from the East before the 17th century AD.Farahnaz Koleini and Linda C. Prinsloo acknowledge the financial contribution from the National Research Foundation (NRF) of South Africa and Philippe Colomban from EGIDE PROTEA.http://www.journals.elsevier.com//journal-of-cultural-heritage2017-05-31hb2016Anthropology and ArchaeologyPhysic

Antioxidant and in vitro antidiabetic activities of Peperomia pellucida (L.) Kunth extract

Peperomia pellucida (L.) is commonly used as a herbal plant. Its effectiveness in treating inflammatory diseases, digestive disorders, and cancer in tropical and subtropical countries was introduced, especially in field of folk medicine. However, this plant species has not been studied widely in Vietnam, especially for its biological activities. This study was done to determine the antioxidant capacity of P. pellucida by using in vitro and in vivo methods, as well as its inhibitory ability to α-amylase enzyme activity. The total polyphenolic and flavonoid contents of P. pellucida extract were reported to be 359.91±0.77 mg GAE/g and 200.28±1.23 mg QE/g extract, respectively. The results showed the in vitro antioxidant activity of P. pellucida extract in four methods, including DPPH, and ABTS.+, RP and TAC, had EC50 values of 730.34 μg/mL, 84.33 μg/mL, 95.28 μg/mL, respectively, and Abs0.5 value of 114.73 μg/mL. Under H2O2-induced oxidative stress, fruit flies that were raised in the feed medium supplemented with a concentration of 1 mg/mL of P. pellucida extract showed their average survival time, 50% survival time, and 10% survival time at 1.6 times, 1.8 times, and 1.62 times, respectively, higher than those of the control treatment. The ability to inhibit the α-amylase activity in P. pellucida extract was determined with an EC50 value of 115.32±2.65 μg/mL compared with the commercial drug of 18.67±0, 01 μg/mL. The research results showed that P. pellucida is a potential species in the study of natural compounds with antioxidant and antidiabetic activities

Retrospective analysis assessing the spatial and temporal distribution of paediatric acute respiratory tract infections in Ho Chi Minh City, Vietnam.

BACKGROUND: Acute respiratory tract infections (ARIs) are the leading cause of morbidity and mortality in young children in low/middle-income countries. Using routine hospital data, we aimed to examine the spatial distribution, temporal trends and climatic risk factors of paediatric ARIs in Vietnam. METHODS: Data from hospitalised paediatric (<16 years) patients with ARIs residing in Ho Chi Minh City (HCMC) between 2005 and 2010 were retrieved from the two main Children's Hospitals and the Hospital for Tropical Diseases in HCMC. Spatial mapping and time series analysis were performed after disaggregating data into upper respiratory tract infections (URIs) and lower respiratory tract infections (LRIs). RESULTS: Over the study period, there were 155 999 paediatric patients admitted with ARIs (33% of all hospital admissions). There were 68 120 URIs (14%) and 87 879 LRIs (19%). The most common diagnoses were acute pharyngitis (28% of all ARI), pneumonia (21%), bronchitis (18%) and bronchiolitis (16%). A significant increasing trend over time was found for both URIs (mean weekly incidence per 1000 population, I=3.12), incidence rate ratio for 1-week increase in time (RR 1.0, 95% CI 1.02 to 1.17) for URI and (I=4.02, RR 1.08 (95% CI 1.006 to 1.16)) for LRI. The weekly URI incidence peaked in May-June and was significantly associated with lags in weekly URI incidence and the average humidity, rainfall and water level. The weekly LRI incidence exhibited significant seasonality (P<0.0001), with an annual peak in September-October and was significantly associated with lags in weekly LRI incidence and lags in weekly average temperature, rainfall and water level. CONCLUSIONS: ARIs are a leading cause of childhood hospitalisation in HCMC, Vietnam. The incidence of ARIs was higher in the wet season and in specific HCMC districts. These results may guide health authorities in where and when to effectively allocate resources for the prevention and control of ARIs