229 research outputs found
New primitives of controlled elements F2/4 for block ciphers
This paper develops the cipher design approach based on the use of data-dependent operations (DDOs). A new class of DDO based on the advanced controlled elements (CEs) is introduced, which is proven well suited to hardware implementations for FPGA devices. To increase the hardware implementation efficiency of block ciphers, while using contemporary FPGA devices there is proposed an approach to synthesis of fast block ciphers, which uses the substitution-permutation network constructed on the basis of the controlled elements F2/4 implementing the 2 x 2 substitutions under control of the four-bit vector. There are proposed criteria for selecting elements F2/4 and results on investigating their main cryptographic properties. It is designed a new fast 128-bit block cipher MM-128 that uses the elements F2/4 as elementary building block. The cipher possesses higher performance and requires less hardware resources for its implementation on the bases of FPGA devices than the known block ciphers. There are presented result on differential analysis of the cipher MM-12
TÍNH CHẤT PHI CỔ ĐIỂN CỦA TRẠNG THÁI KẾT HỢP CẶP THÊM VÀ BỚT PHOTON HAI MODE
In this paper, we study the non-classical properties such as two-mode sum squeezing, two-mode difference squeezing, and higher-order two-mode antibunching properties of the photon-added-and-subtracted two-mode pair coherent state (PAASTMPCS). The results in the squeezing property show that the PAASTMPCS has two-mode sum squeezing but no two-mode difference squeezing. The two-mode sum squeezing of the PAASTMPCS always appears when adding and subtracting photons to two modes of a pair coherent state (PCS). Furthermore, the PAASTMPCS has higher-order two-mode antibunching in any order, and this property is enhanced when photons are simultaneously added and subtracted to two modes of the PCS. Thereby, the role of the photon addition and the photon subtraction has been confirmed by enhancing the non-classical properties of the PAASTMPCS.Trong bài báo này chúng tôi nghiên cứu các tính chất phi cổ điển như tính chất nén tổng hai mode, nén hiệu hai mode và tính chất phản kết chùm hai mode bậc cao của trạng thái kết hợp cặp thêm và bớt photon hai mode (PAASTMPCS). Các kết quả khảo sát về tính chất nén cho thấy rằng trạng thái PAASTMPCS có tính chất nén tổng hai mode nhưng không có tính chất nén hiệu hai mode. Tính chất nén tổng hai mode của trạng thái PAASTMPCS luôn xuất hiện khi thêm và bớt photon vào trạng thái kết hợp cặp (PCS). Ngoài ra, kết quả khảo sát chỉ ra rằng trạng thái PAASTMPCS còn có tính chất phản kết chùm hai mode bậc cao và tính chất này được tăng cường khi thêm và bớt photon vào PCS. Qua đó, vai trò của việc thêm và bớt photon đã được khẳng định thông qua việc tăng cường tính chất phi cổ điển của trạng thái PAASTMPCS
A STUDY ON THE SYNTHESIS OF MgAl2O4 SPINEL BY STARCH ASSISTED SOL-GEL PROCESS
In this paper, the synthesis of ceramic spinel MgAl2O4 by starch assisted sol - gel process is presented. The gel mixture was prepared by using Mg(NO3)2.6H2O, Al(NO3)3.9H2O as precursors and starch as a gel agent. The study focused on relevant components of gel mixture and the calcinating temperature. The results showed that suitable molar proportion of Mg2+/Al3+; starch/(Mg2+ + Al3+) and H2O/starch were 0.5, 0.4 and 60, respectively. The calcination at 1100 oC for 60 minutes was suitable for forming phase of spinel. The product was a single phase of spinel MgAl2O4 with excellent crystallinity and uniform size in the range of 300 to 400 nm
Isolation and production of polyhydroxybutyrate (PHB) from Bacillus pumilus NMG5 strain for bioplastic production and treatment of wastewater from paper factories
Polyhydroxybutyrate (PHB) has the potential to replace traditional plastics and limit environmental pollution caused by plastic waste. This study combined wastewater treatment with PHB production to reduce costs. Bacteria capable of synthesizing PHB were isolated from paper mill wastewater and identified using Matrix Assisted Laser Desorption/Ionization–Time of Flight (MALDI-TOF) mass spectrometry and 16S rRNA gene analysis. Bacillus pumilus NMG5 strain was found to have a good yield in modified Nutrient Broth culture, reaching 42.28% of dry biomass. The PHB product was analyzed using FTIR spectroscopy and 1H NMR spectroscopy. The bacterial strain was also tested for its ability to treat paper mill wastewater, and it showed impressive results in terms of biochemical oxygen demand (COD), total nitrogen, and total phosphorus, with efficiencies of 95.93%, 79.36%, and 83.55%, respectively. The study found that wastewater treatment combined with PHB production was a promising solution to reduce costs and limit environmental pollution. The bacterial strain B. pumilus NMG5 had a high yield of PHB, and the PHB product was of high quality, as confirmed by FTIR and 1H NMR spectroscopy. Furthermore, the bacterial strain showed impressive results in treating paper mill wastewater with high COD, total nitrogen, and total phosphorus efficiencies. These results suggest that this harmless bacterium could be used in paper mill wastewater treatment systems to produce PHB, providing a sustainable and environmentally friendly solution
INFLUENCE OF SYNTHESIS FACTORS ON PROPERTIES OF GEOPOLYMERS BASED ON RED MUD AND RICE HUSK ASH
In this paper, the effect of mixing ratio of raw materials, curing temperature and time on geopolymerization between red mud and rice husk ash were investigated. The results showed that the optimum conditions were SiO2/Al2O3 ratio of 4 and Na2O/Al2O3 ratio of 2.0, curing temperature of 100oC and curing time of 24 hours. The compressive strength, bulk density, total shrinkage of the obtained product were 22.8 MPa, 2.39 g.cm-3, 15%, respectively that met requirement of unsintered bricks using for construction
The potential of combining UAV and remote sensing in supporting precision mapping of irrigation systems for paddy land in urban agricultural areas: study case in the Hoa Vang district, Danang city, Central Vietnam
This research was carried out to test the potential of combining unmanned aerial vehicle (UAV) and remote sensing (RS) to support precision mapping of irrigation systems for paddy land. The study area is an urban/agricultural area of Central Vietnam. The Sentinel-2A imagery acquired on 30 June 2018 was interpreted according an object-based classification method aiming to map paddy land and irrigation systems for the Hoa Vang district; the total accuracy was 91.33% with a Kappa coefficient of 0.87. However, with the spatial resolution from the Sentinel-2A images (20 meters x 20 meters) it was difficult to classify paddy land and water from other objects within small and scattered parcel areas. This research was designed on five experimental flying zones, collecting 2,085 images by the UAV. With the very high spatial resolution data of the UAV, it was possible to clearly identify the boundaries of paddy land parcels, water sources such as rivers and lakes, and other objects such as canals and concrete irrigation systems. This classification derived from the orthogonal images from the five experimental zones using an object-based classification method, correcting the interpretation results of the Sentinel 2A images. Outcomes indicate that, the combination of UAV and RS can be applied to support precision mapping of irrigation systems for paddy land in urban agricultural areas.Nghiên cứu này được thực hiện nhằm thử nghiệm khả năng kết hợp giữa UAV với viễn thám trong hỗ trợ độ chính xác của bản đồ hệ thống nước tưới cho đất trồng lúa ở vùng nông nghiệp đô thị tại Miền trung Việt Nam. Ảnh viễn thám Sentinel- 2A thu nhận vào 30/6/2018 đã được giải đoán bằng phương pháp định hướng đối hướng để thành lập bản đồ hệ thống nguồn nước tưới cho huyện Hòa Vang vào năm 2018, với kết quả độ chính xác tổng số là 91,33% và hệ số kappa là 0,87. Mặc dù với kết quả giải đoán có độ chính xác cao nhưng với độ phân giải không gian của ảnh Sentinel-2A là 20m x 20m rất khó để phân loại được các vùng đất lúa có diện tích nhỏ và phân bố phân tán. Nghiên cứu này đã thiết kế 5 khu vực bay thử nghiệm với 2.085 ảnh để thu thập dữ liệu từ UAV. Có thể thấy rằng dữ liệu ảnh từ UAV với độ phân giải siêu cao có thể nhận diện và phân biệt được một cách rõ ràng không chỉ ranh giới của các thửa đất lúa, hệ thống nguồn nước như sông hồ, mà còn cả những đối tượng kênh mương thủy lợi nhỏ. Kết quả giải đoán các ảnh bay chụp bằng UAV sử dụng dụng phương pháp định hướng đối tượng, nghiên cứu này đã hiệu chỉnh được kết quả giải đoán ảnh Sentinel 2A. Kết quả cho thấy việc kết hợp dữ liệu viễn thám với UAV là hoàn toàn có khả năng sử dụng để hỗ trợ độ chính xác thành lập bản đồ hệ thống nguồn nước cho đất trồng lúa ở vùng nông nghiệp đô thị
On the Out of Distribution Robustness of Foundation Models in Medical Image Segmentation
Constructing a robust model that can effectively generalize to test samples
under distribution shifts remains a significant challenge in the field of
medical imaging. The foundational models for vision and language, pre-trained
on extensive sets of natural image and text data, have emerged as a promising
approach. It showcases impressive learning abilities across different tasks
with the need for only a limited amount of annotated samples. While numerous
techniques have focused on developing better fine-tuning strategies to adapt
these models for specific domains, we instead examine their robustness to
domain shifts in the medical image segmentation task. To this end, we compare
the generalization performance to unseen domains of various pre-trained models
after being fine-tuned on the same in-distribution dataset and show that
foundation-based models enjoy better robustness than other architectures. From
here, we further developed a new Bayesian uncertainty estimation for frozen
models and used them as an indicator to characterize the model's performance on
out-of-distribution (OOD) data, proving particularly beneficial for real-world
applications. Our experiments not only reveal the limitations of current
indicators like accuracy on the line or agreement on the line commonly used in
natural image applications but also emphasize the promise of the introduced
Bayesian uncertainty. Specifically, lower uncertainty predictions usually tend
to higher out-of-distribution (OOD) performance.Comment: Advances in Neural Information Processing Systems (NeurIPS) 2023,
Workshop on robustness of zero/few-shot learning in foundation model
THE FACTORS EFFECT TO THE FINANCIAL EFFICIENCY OF FDI (FOREIGN DIRECT INVESTMENT) ENTERPRISES LOCATED IN HO CHI MINH CITY-VIET NAM
ABSTRAC
THE FACTORS EFFECT TO THE FINANCIAL EFFICIENCY OF FDI (FOREIGN DIRECT INVESTMENT) ENTERPRISES LOCATED IN HO CHI MINH CITY-VIET NAM
ABSTRAC
A Systematic and Critical Review on the Research Landscape of Finance in Vietnam from 2008 to 2020
This paper endeavors to understand the research landscape of finance research in Vietnam during the period 2008 to 2020 and predict the key defining future research directions. Using the comprehensive database of Vietnam’s international publications in social sciences and humanities, we extract a dataset of 314 papers on finance topics in Vietnam from 2008 to 2020. Then, we apply a systematic approach to analyze four important themes: Structural issues, Banking system, Firm issues, and Financial psychology and behavior. Overall, there have been three noticeable trends within finance research in Vietnam: (1) assessment of financial policies or financial regulation, (2) deciphering the correlates of firms’ financial performances, and (3) opportunities and challenges in adopting innovations and ideas from foreign financial market systems. Our analysis identifies several fertile areas for future research, including financial market analysis in the post-COVID-19 eras, fintech, and green finance
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