Explicit Construction of Minimum Bandwidth Rack-Aware Regenerating Codes

In large data centers, storage nodes are organized in racks, and the cross-rack communication dominates the system bandwidth. We explicitly construct codes for exact repair of single node failures that achieve the optimal tradeoff between the storage redundancy and cross-rack repair bandwidth at the minimum bandwidth point (i.e., the cross-rack bandwidth equals the storage size per node). Moreover, we explore the node repair when only a few number of helper racks are connected. Thus we provide explicit constructions of codes for rack-aware storage with the minimum cross-rack repair bandwidth, lowest possible redundancy, and small repair degree (i.e., the number of helper racks connected for repair).Comment: 4 pages, 1 figure. arXiv admin note: text overlap with arXiv:2101.0873

An oil painters recognition method based on cluster multiple kernel learning algorithm

A lot of image processing research works focus on natural images, such as in classification, clustering, and the research on the recognition of artworks (such as oil paintings), from feature extraction to classifier design, is relatively few. This paper focuses on oil painter recognition and tries to find the mobile application to recognize the painter. This paper proposes a cluster multiple kernel learning algorithm, which extracts oil painting features from three aspects: color, texture, and spatial layout, and generates multiple candidate kernels with different kernel functions. With the results of clustering numerous candidate kernels, we selected the sub-kernels with better classification performance, and use the traditional multiple kernel learning algorithm to carry out the multi-feature fusion classification. The algorithm achieves a better result on the Painting91 than using traditional multiple kernel learning directly

New Carbohydrate-Based Anti-Cancer And Anti-Bacterial Vaccines

The unique carbohydrates expressed on the surface of cancer, bacterial, viral and fungal cells are excellent target antigens for the design of therapeutic or preventive vaccines. However, as antigens carbohydrates have problems. First, carbohydrates usually have low immunogenicity. Second, even if immunogenic, carbohydrates typically elicit T cell-independent immune responses. To overcome these problems and design useful vaccines based on carbohydrate antigens, they are usually coupled with carrier proteins to form conjugates to enhance the immunogenicity of the antigens. However, there are still some issues existing in glycoprotein vaccines, such as poor reproducibility of the conjugates, difficulties in quality control and so on. To deal with these issues, our group explored a strategy to utilize synthetic carbohydrate antigens with well-defined structures for the construction of glycoprotein vaccines. In the meantime, our group has also developed new vaccine carriers, such as monophosphoryl lipid A (MPLA), to construct full-synthetic carbohydrate-based vaccines that have well-defined structures and improved immunological properties. The main aims of this dissertation are to study and evaluate these semi- and full-synthetic glycoconjugates and develop carbohydrate-based vaccines against cancer and bacteria. The first part of this dissertation (Chapters 2 and 3) is focused on antitumor vaccines targeting at tumor-associated carbohydrate antigens (TACAs). For TACAs, in addition to the problems associated with carbohydrate antigens mentioned above, there is another problem, namely immunotolerance, due to their structural similarity to normal carbohydrates on normal cells. To overcome the immunotolerance problem, our group developed a novel immunotherapeutic strategy based on glycoengineering of sialo-TACAs on cancer cells. An important requirement for this strategy to work is to engineer cancer cells to express unnatural sialo-TACAs. In Chapter 2, a convenient method was developed for the quantification of various sialic acids expressed by cells and used to analyze the efficiency of N-phenylacetyl-D-mannosamine (ManNPhAc) to metabolically glycoengineer SKMEL-28 cancer cell. In specific, after cancer cells were cultured with ManNPhAc, the cells were treated with 2M acetic acid to release sialic acids and then with 1,2-diamino-4,5-methylenedioxybenzene (DMB). Sialic acids could react with DMB to form the corresponding derivatives that had strong UV absorptions. The reaction mixture was then applied to HPLC-UV analysis to determine the amounts and the ratios of natural sialic acid and its unnatural analog. It was confirmed that after incubation with ManNPhAc, the SKMEL-28 cell was effectively glycoengineered to express a significant amount of unnatural sialic acid. Another requirement for the new cancer immunotherapeutic strategy is to have effective vaccines made of TACAs that contain the correspondingly modified sialic acid. In Chapter 3, a new construct of carbohydrate-based cancer vaccines with MPLA as the carrier molecule and a build-in adjuvant, which are full-synthetic and potentially possess strong and self-adjuvanting immunological activities, were investigated. For this purpose, four MPLA analogs were prepared and immunologically evaluated to identify the ideal vaccine carrier. It was confirmed MPLA conjugates of chemically modified sTn antigen induced robust immune responses, thus they can be used as effective vaccines for the new cancer immunotherapeutic strategy. Furthermore, the optimized MPLA was used to develop Globo H-based anti-breast cancer vaccine. The immunological results of Globo H-keyhole limpet hemocyanin (KLH) and Globo H-MPLA conjugates indicated that the Globo H-MPLA conjugate had better immunogenicity than that of Globo H-KLH, including the capability of stimulating a T cell-mediated immunity. Therefore, Globo H-MPLA had the potential for being further developed into clinically useful vaccines. The second part of this dissertation (Chapter 4) is focused on the development of antibacterial vaccines based on their capsular polysaccharide antigens. Instead of using polysaccharides isolated from bacterial cells, oligomers of the polysaccharide antigen repeating units were synthesized and then conjugated with a carrier protein, such KLH, or a MPLA derivative to form semi- or full-synthetic vaccines. The resultant conjugates were evaluated in mice and their structure-activity relationships were analyzed to identify the proper repeating unit oligomers for vaccine development. In this dissertation, two types of bacteria Haemophilus Influenzae type b (Hib) and group C Neisseria meningitidis were studied. The target antigen for Hib was the repeating ribosylribitol phosphate (RRP) polysaccharide, and for group C N. meningitides, the target antigen was α[2,9]-linked polysialic acid. Immunological studies of these conjugates suggested that they all can stimulate strong T-cell mediated immune responses. Most importantly, it was concluded that short oligomers of bacterial polysaccharide antigens can be highly immunogenic and induce immune responses that can recognize and bind the target pathogens. In conclusion, in this dissertation, a new method was developed for quantitative analysis of cell surface sialic acids and analysis of the efficiency of sialic acid metabolic engineering. This method can be broadly useful for various cells and sialic acid analogs. In this dissertation, two different vaccine strategies, which could lead to semi- and fully synthetic vaccines, against cancer and bacteria have been investigated in great details. These vaccines showed promising properties and are worth further investigation. More importantly, the results of this dissertation have provided proof of principle for the new strategies, which may be widely applicable to other cancer and bacteria

Empirical research on the evaluation model and method of sustainability of the open source ecosystem

The development of open source brings new thinking and production modes to software engineering and computer science, and establishes a software development method and ecological environment in which groups participate. Regardless of investors, developers, participants, and managers, they are most concerned about whether the Open Source Ecosystem can be sustainable to ensure that the ecosystem they choose will serve users for a long time. Moreover, the most important quality of the software ecosystem is sustainability, and it is also a research area in Symmetry. Therefore, it is significant to assess the sustainability of the Open Source Ecosystem. However, the current measurement of the sustainability of the Open Source Ecosystem lacks universal measurement indicators, as well as a method and a model. Therefore, this paper constructs an Evaluation Indicators System, which consists of three levels: The target level, the guideline level and the evaluation level, and takes openness, stability, activity, and extensibility as measurement indicators. On this basis, a weight calculation method, based on information contribution values and a Sustainability Assessment Model, is proposed. The models and methods are used to analyze the factors affecting the sustainability of Stack Overflow (SO) ecosystem. Through the analysis, we find that every indicator in the SO ecosystem is partaking in different development trends. The development trend of a single indicator does not represent the sustainable development trend of the whole ecosystem. It is necessary to consider all of the indicators to judge that ecosystem’s sustainability. The research on the sustainability of the Open Source Ecosystem is helpful for judging software health, measuring development efficiency and adjusting organizational structure. It also provides a reference for researchers who study the sustainability of software engineering

Healthy or Not: A Way to Predict Ecosystem Health in GitHub

With the development of open source community, through the interaction of developers, the collaborative development of software, and the sharing of software tools, the formation of open source software ecosystem has matured. Natural ecosystems provide ecological services on which human beings depend. Maintaining a healthy natural ecosystem is a necessity for the sustainable development of mankind. Similarly, maintaining a healthy ecosystem of open source software is also a prerequisite for the sustainable development of open source communities, such as GitHub. This paper takes GitHub as an example to analyze the health condition of open source ecosystem and, also, it is a research area in Symmetry. Firstly, the paper presents the healthy definition of GitHub open source ecosystem health and, then, according to the main components of natural ecosystem health, the paper proposes the health indicators and health indicators evaluation method. Based on the above, the GitHub ecosystem health prediction method is proposed. By analyzing the projects and data collected in GitHub, it is found that, using the proposed evaluation indicators and method, we can analyze the healthy development trend of the GitHub ecosystem and contribute to the stability of ecosystem development

Analysis of four achaete-scute homologs in Bombyx mori reveals new viewpoints of the evolution and functions of this gene family

<p>Abstract</p> <p>Background</p> <p><it>achaete-scute </it>complexe (<it>AS-C</it>) has been widely studied at genetic, developmental and evolutional levels. Genes of this family encode proteins containing a highly conserved bHLH domain, which take part in the regulation of the development of central nervous system and peripheral nervous system. Many <it>AS-C </it>homologs have been isolated from various vertebrates and invertebrates. Also, <it>AS-C </it>genes are duplicated during the evolution of Diptera. Functions besides neural development controlling have also been found in <it>Drosophila AS-C </it>genes.</p> <p>Results</p> <p>We cloned four <it>achaete-scute </it>homologs (<it>ASH</it>) from the lepidopteran model organism <it>Bombyx mori</it>, including three proneural genes and one neural precursor gene. Proteins encoded by them contained the characteristic bHLH domain and the three proneural ones were also found to have the C-terminal conserved motif. These genes regulated promoter activity through the Class A E-boxes <it>in vitro</it>. Though both <it>Bm-ASH </it>and <it>Drosophila AS-C </it>have four members, they are not in one by one corresponding relationships. Results of RT-PCR and real-time PCR showed that <it>Bm-ASH </it>genes were expressed in different larval tissues, and had well-regulated expressional profiles during the development of embryo and wing/wing disc.</p> <p>Conclusion</p> <p>There are four <it>achaete-scute </it>homologs in <it>Bombyx mori</it>, the second insect having four <it>AS-C </it>genes so far, and these genes have multiple functions in silkworm life cycle. <it>AS-C </it>gene duplication in insects occurs after or parallel to, but not before the taxonomic order formation during evolution.</p

Manipulating Electromagnetic Waves with Zero Index Materials

Zero-index material is a typical metamaterial with an effective zero refractive index, possessing a variety of exotic electromagnetic properties and particular functionalities. We have considered two kinds of zero-index materials with the first one a nearly matched zero index made of magnetic metamaterial and the second one a radially anisotropic zero index. The magnetic metamaterial-based systems are shown to be significant in wavefront engineering and flexibly tunable by an external magnetic field and a temperature field. The radially anisotropic zero-index-based systems can remarkably enhance the omnidirectional isotropic radiation by enclosing a line source and a dielectric particle within a shell configuration. The physical origin lies in that the dielectric particle effectively rescatters the trapped anisotropic higher order modes and converts them into the isotropic 0th order mode radiated outside the system. The case for the system with the loss is then examined and the energy compensation with a gain particle is also demonstrated