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Ra đa xuyên đất (Ground Penetrating Radar: GPR) là phương pháp địa vất lý sử dụng sóng điện từ để nghiện cứu các cấu trúc tầng nông dưới mặt đất như dự báo sạt lở, sụt lún, vẽ bản đồ công trình ngầm đô thị, khảo cổ, gia thông,… Sóng GPR được phát dưới dạng các xung sóng điện từ nhờ anten phát, lan truyền trong môi trường và anten thu sẽ nhận lại tín hiệu phản xạ từ các mặt ranh giới hoặc các đối tượng có các thông số thuận lợi cho việc phản xạ sóng điện từ. GPR có rất nhiều thuận lợi so với các phương pháp địa vật lý khác như: không phá hủy, tốc độ thu thập số liệu nhanh, độ phân giải và độ chính xác cao… Tuy đã được sử dụng ở Việt Nam nhiều năm nay, những vẫn chưa được ứng dụng rộn...
A random geometric graph g(n, r) is a graph resulting from placing n points uniformly at random on the unit square (or on the unit disk) and connecting two points iff their Euclidean distance is at most the radius r(n). Recently, this class of random graphs has gained relevance as a natural model for wireless ad-hoc and sensor networks. Investigating properties of these graphs can unearth properties of the real-life systems they model and allow for the design of efficient algorithms. In this work, we study properties of random geometric graphs motivated by challenges encounter in sensor networks applications. Sensor networks are constructed from a large number of low-cost, low-power ...
In 1988 Persi Diaconis considered the following random walk on Zn. Pick k values from Zitand then repeatedly choose one of these values at random. This choice determines a random walk starting at 0 and the natural question that arises is, how long does it take the walk to get close to uniformly distributed on Zn for "most" choices of the k values. In 1989 A. Greenhalgh, in his thesis, gave a lower bound for a random walk on Zn. A paper written by J. Dai and M. Hildebrand in 1997 considered random walks on Zn without restrictions on n and in the case where k is a constant. It is important to note that the set of k values were chosen at random but were subject to certain divisibility re...
September 11 and hurricane Katrina have shown that timely information is important not only for disaster prevention but especially valuable in effective disaster response. From the point of view of information and communication technologies, the challenge is how to coordinate information sharing effectively among members of a complex decision-making team (e.g. the first responders for a disaster). A common difficulty is to provide useful and time-sensitive information to team members quickly but at the same time not overwhelm them with irrelevant information. This problem has also been encountered in other application domains that require effective communication in a team environment:...
Institutional accreditation is an excellent vehicle for facilitating change toward the improvement of quality in higher education. It is fulfilled by three phases: (a) a self-study, (b) a peer review, and (c) a decision by the accrediting agency. Self-study is at the heart of institutional accreditation; however, it is not always favored. Some participants consider it to be a waste of time and resources. Yet, self-study, if properly approached and packaged, can help ensure a high-quality future for the institution. This qualitative case study research explored the internal review (self-study) processes used by a Level VI public university, United States Sigma University (USSU) (a pseu...
The article discusses the use of school assignments about social justice as a method of teaching writing to adolescents. It focuses on the authors' experience of using social justice education to emphasize multicultural education and increase students articulation and criticism skills. The authors argue that high school teachers need real-time examples of social justice education in order to make similar programs work in their own classrooms. They explore the use of narrative, poetry, and exposition to engage students in social justice issues and critical thinking.
In this dissertation,, we shall consider three problems in combinatorics and graph theory. These three problems can all be classified as extremal problems. The first chapter considers another variant of graph Ramsey theory. In 2003, Bollobas asked the following question: Whenever we colour the edges of the complete graph Kn with r colours, on how many vertices can we find a k-connected subgraph using at most s colours? With Morris and Prince (see also ,  and ), we were able to provide several partial solutions to Bollobas' question. However, the problem remains largely unsolved. So, we shall also provide many conjectures and open problems. The second chapter consider...
The article discusses job employment prospects for educators and the effects financial recessions can have on the teaching profession. The author explains the possibility of teacher layoffs as school funding is reduced and examines a number of opportunities and changes this trend presents, including the hiring of teachers with greater qualifications, increased student enrollment in public schools as private schools become less affordable, and a greater reliance of educational technology, which is often more affordable and available than traditional support materials. Other possible benefits of weak economies on the teaching profession, such as improved retirement and pension packages ...
One important consideration in realizing dependable computing systems and networks is to uncover vulnerabilities in their designs to adversarial attacks. Currently, the designs of these systems employ different forms of adaptation mechanisms in order to optimize their performance by ensuring that desirable properties, such as stability, efficiency and fairness, are not compromised. This thesis discovers and studies a new type of adversarial attacks that target such adaptation mechanisms by exploiting their dynamics of operation - i.e., the characteristics of their transient behavior. We coin this new breed of adversarial attacks, Reduction of Quality (RoQ) attacks. The premise of RoQ ...
Recently the environmental movement has seen much success and progress under a newly-framed green paradigm. Yet, despite the proliferation of national attention to, and public interest in, the go-green mentality, environmental, education still seems to be truck within the budding sustainability environmental paradigm. This critical essay shares lessons that environmental education can learn through incorporating a human benefits approach. Ultimately, this essay calls for a reflection on environmental education’s presence within the budding sustainability movement and calls for the “ humanization” of environmental education discourse and pedagogical practice
Regression and neural network modeling of resilient modulus based on routine soil properties and stress states
Resilient modulus (MR) is one of the fundamental material properties in the mechanistic analysis and structural design of roadway pavements. In the current and the proposed mechanistic-empirical design guides by AASHTO, MR is used to characterize subgrade soils. Resilient modulus of subgrade soils are generally determined by conducting repeated load triaxial tests in the laboratory on remolded or undisturbed specimens. In the proposed AASHTO design guide, three hierarchical design levels are suggested. In Level 1, the required input values for MR are obtained from laboratory or field tests. For Level 2 and Level 3 designs, however, the MR values are either obtained from the agency dat...
The Sir2 proteins, also known as sirtuins, represent a large and highly conserved family of NAD+-dependent protein deacetylases that control various fundamental biological proceses. The baker’s yeast, Saccharomyces cerevisiae, has five members of this family, Sir2p and Hst1-4p, important for regulation of transcriptional silencing and genomic stability. Hst3p and Hst4p are two redundant sirtuins with the major role in maintenance of genomic stablity. They control genomic stability by regulating the level of acetylation of histone H3 lysine 56. This residue, present in the core of the nucleosome surface, is acetylated during the S phase of the cel cycle and contributes to the repair p...
One of the hallmarks of the eukaryotic cell is the possession of a nuclear envelope. Transport of macromolecules between the nuclear and cytoplasmic compartments is mainly regulated by the small GTPase, Ran. The nucleotide exchange factor RCC1 catalyzes formation of RanGTP, whereas the hydrolysis of RanGTP is stimulated by RanGAP1 and RanBP1. Because RCC1 is chromatin-bound throughout the cell cycle while RanGAP1 and RanBP1 are cytoplasmic, the concentration of RanGTP is high near the chromatin. This RanGTP gradient is essential for many cellular processes, including nuclear transport during interphase, mitotic spindle formation, and nuclear envelope assembly during mitosis. During t...
During the development of the vertebrate nervous system, cellular proliferation and differentiation result in the formation of a large number of specialized physical structures composed of many different types of cells. The phenotypic properties of a cell are largely controlled by the complement of proteins that the cell expresses. Thus, the formation of properly functioning neuronal circuitry requires precisely coordinated regulation of gene expression. Tissue-specific transcription factors play a critical role in the process of development by exerting spatiotemporal control over the expression of their specific target genes. Hundreds of transcription factors have been identified ...
The article focuses on the impact of online social media on relationships, community, and identity in the future. It offers an more people spend more of their social lives online and what they imply for organizations in the coming years. It discusses how the internet has reshaped social lives, enticing people into a virtual world where traditional interactions require new protocols. It cites some of the disadvantages and advantages of online social media and notes its influences to relationships, social ties, and family.INSET: THE
In this thesis we study two different aspects of certain classes of arithmetic groups. In the first chapter, we prove a classification for the relative growth type of lattices in higher rank algebraic groups. It states that the growth of number of points in the intersection of balls with arbitrary subgroups of lattices in higher rank algebraic groups is either polynomial or exponential. This generalizes a theorem of Lubotzky, Mozes, and Raghunathan who proved the same statement for cyclic subgroups. The second part of the thesis proposes a method for finding a lower bound for the Kazhdan constants for the tame automorphisms of the free nilpotent groups. Such groups arise very natural...
Relative property (T) has recently been used to show the existence of a variety of new rigidity phenomena, for example in von Neumann algebras and the study of orbit-equivalence relations. However, until recently there were few examples of group pairs with relative property (T) available through the literature. This motivated the following main result: A finitely gen¬erated group F admits a special linear representation with non-amenable 1l -Zariski closure if and only if it acts on an Abelian group A (of finite nonzero Q-rank) so that the corresponding group pair (F x A, A) has relative property (T). The proof is constructive. The main ingredients are Furstenberg's celebrated lemma ...