117,844 research outputs found
Chan An Ancient Maya Farming Community
No full textThe farming community of Chan thrived for over twenty centuries, surpassing the longevity of many larger Maya urban centers. Between 800 BC and 1200 AD it was a major food production center, and this collection of essays reveals the important role played by Maya farmers in the development of ancient Maya society. Chan offers a synthesis of compelling and groundbreaking discoveries gathered over ten years of research at this one archaeological site in Belize. The contributors develop three central themes, which structure the book. They examine how sustainable farming practices maintained the surrounding forest, allowing the community to exist for two millennia. They trace the origins of elite Maya state religion to the complex religious belief system developed in small communities such as Chan. Finally, they describe how the group-focused political strategies employed by local leaders differed from the highly hierarchical strategies of the Classic Maya kings in their large cities. In breadth, methodology, and findings, this volume scales new heights in the study of Maya society and culture.Cover -- Title -- Copyright -- Contents -- List of Figures -- List of Tables -- Foreword -- Acknowledgments -- 1. Introducing the Chan Site: Farmers in Complex Societies -- Part 1. Time, Space, and Landscapes -- 2. A Changing Cultural Landscape: Settlement Survey and GIS at Chan -- 3. Ceramics and Chronology at Chan -- 4. Agricultural Practices at Chan: Farming and Political Economy in an Ancient Maya Community -- 5. Agroforestry and Agricultural Production of the Ancient Maya at Chan -- Part 2. Life in a Farming Community Center -- 6. Ritual in a Farming Community -- 7. Nonroyal Governance at Chan's Community Center -- 8. "Empty" Spaces and Public Places: A Microscopic View of Chan's Late Classic West Plaza -- Part 3. Diversity across the Chan Community -- 9. Recognizing Difference in Small-Scale Settings: An Examination of Social Identity Formation at the Northeast Group, Chan -- 10. Organization of Chert Tool Economy during the Late and Terminal Classic Periods at Chan: Preliminary Thoughts Based upon Debitage Analyses -- 11. Limestone Quarrying and Household Organization at Chan -- Part 4. Bodies, Material Culture, and Meaning -- 12. The Chan Community: A Bioarchaeological Perspective -- 13. Creating Community with Shell -- 14. Obsidian Acquisition, Trade, and Regional Interaction at Chan -- 15. Contextualizing Ritual Behavior: Caches, Burials, and Problematical Deposits from Chan's Community Center -- Part 5. Conclusion -- 16. Learning from an Ancient Maya Farming Community -- References -- List of Contributors -- Index -- A -- B -- C -- D -- E -- F -- G -- H -- I -- J -- K -- L -- M -- N -- O -- P -- Q -- R -- S -- T -- V -- W -- X -- YThe farming community of Chan thrived for over twenty centuries, surpassing the longevity of many larger Maya urban centers. Between 800 BC and 1200 AD it was a major food production center, and this collection of essays reveals the important role played by Maya farmers in the development of ancient Maya society. Chan offers a synthesis of compelling and groundbreaking discoveries gathered over ten years of research at this one archaeological site in Belize. The contributors develop three central themes, which structure the book. They examine how sustainable farming practices maintained the surrounding forest, allowing the community to exist for two millennia. They trace the origins of elite Maya state religion to the complex religious belief system developed in small communities such as Chan. Finally, they describe how the group-focused political strategies employed by local leaders differed from the highly hierarchical strategies of the Classic Maya kings in their large cities. In breadth, methodology, and findings, this volume scales new heights in the study of Maya society and culture.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
K.j. Chan Offenbach A. M. Spezialhaus für Modewaren & Wäsche Complette Wohnungseinrichtungen
No full textK.J. CHAN OFFENBACH A. M. SPEZIALHAUS FÜR MODEWAREN & WÄSCHE COMPLETTE WOHNUNGSEINRICHTUNGEN
K.j. Chan Offenbach A. M. Spezialhaus für Modewaren & Wäsche Complette Wohnungseinrichtungen ( -
Vickers-Chan-7thGraders_Multiplex_Social .zip
No full textThe dataset representing the multiplex social network in a school in Victoria, Australia.
If you use this dataset in your work either for analysis or for visualization, you should acknowledge/cite the following papers:
Representing Classroom Social Structure. Melbourne: Victoria Institute of Secondary Education
M. Vickers and S. Chan, (1981)
The data were collected by Vickers from 29 seventh grade students in a school in Victoria, Australia. Students were asked to nominate their classmates on a number of relations including the following three (layers):
1. Who do you get on with in the class?
2. Who are your best friends in the class?
3. Who would you prefer to work with?
Students 1 through 12 are boys and 13 through 29 are girls.
There are 29 nodes in total, labelled with integer ID between 1 and 29, with 740 connections.
The multiplex is directed and unweighted, stored as edges list in the file
Vickers-Chan-7thGraders_multiplex.edges
with format
layerID nodeID nodeID weight
(Note: all weights are set to 1)
The IDs of all layers are stored in
Vickers-Chan-7thGraders_layers.txt
</p
Dynamic Geometric Data Structures via Shallow Cuttings
No full textWe present new results on a number of fundamental problems about dynamic geometric data structures:
1) We describe the first fully dynamic data structures with sublinear amortized update time for maintaining (i) the number of vertices or the volume of the convex hull of a 3D point set, (ii) the largest empty circle for a 2D point set, (iii) the Hausdorff distance between two 2D point sets, (iv) the discrete 1-center of a 2D point set, (v) the number of maximal (i.e., skyline) points in a 3D point set. The update times are near n^{11/12} for (i) and (ii), n^{7/8} for (iii) and (iv), and n^{2/3} for (v). Previously, sublinear bounds were known only for restricted "semi-online" settings [Chan, SODA 2002].
2) We slightly improve previous fully dynamic data structures for answering extreme point queries for the convex hull of a 3D point set and nearest neighbor search for a 2D point set. The query time is O(log^2n), and the amortized update time is O(log^4n) instead of O(log^5n) [Chan, SODA 2006; Kaplan et al., SODA 2017].
3) We also improve previous fully dynamic data structures for maintaining the bichromatic closest pair between two 2D point sets and the diameter of a 2D point set. The amortized update time is O(log^4n) instead of O(log^7n) [Eppstein 1995; Chan, SODA 2006; Kaplan et al., SODA 2017]
Orthogonal Range Searching in Moderate Dimensions: k-d Trees and Range Trees Strike Back
No full textWe revisit the orthogonal range searching problem and the exact l_infinity nearest neighbor searching problem for a static set of n points when the dimension d is moderately large. We give the first data structure with near linear space that achieves truly sublinear query time when the dimension is any constant multiple of log n. Specifically, the preprocessing time and space are O(n^{1+delta}) for any constant delta>0, and the expected query time is n^{1-1/O(c log c)} for d = c log n. The data structure is simple and is based on a new "augmented, randomized, lopsided" variant of k-d trees. It matches (in fact, slightly improves) the performance of previous combinatorial algorithms that work only in the case of offline queries [Impagliazzo, Lovett, Paturi, and Schneider (2014) and Chan (SODA'15)]. It leads to slightly faster combinatorial algorithms for all-pairs shortest paths in general real-weighted graphs and rectangular Boolean matrix multiplication.
In the offline case, we show that the problem can be reduced to the Boolean orthogonal vectors problem and thus admits an n^{2-1/O(log c)}-time non-combinatorial algorithm [Abboud, Williams, and Yu (SODA'15)]. This reduction is also simple and is based on range trees.
Finally, we use a similar approach to obtain a small improvement to Indyk's data structure [FOCS'98] for approximate l_infinity nearest neighbor search when d = c log n
Atroposelective Chan-Evans-Lam Amination
No full textThe synthetic control of atropoisomerism along C─N bonds is a major challenge, and methods that allow C─N atroposelective bond formation are rare. This is a problem because each atropoisomer can feature starkly differentiated biological properties. Yet, among the three most practical and applicable classical amination methods available: 1) the Cu-catalyzed Ullmann-Goldberg reaction, 2) the Pd-catalyzed Buchwald-Hartwig reaction, and 3) the Cu-catalyzed Chan-Evans-Lam reaction, none has truly been rendered atroposelective at the newly formed C─N bond. The first ever Chan-Evans-Lam atroposelective amination is herein described with a simple copper catalyst and new PyrOx chiral ligand. This method constitutes a change of paradigm in the field
Andy Chan oral history interview and transcript
No full textThis recording and transcript form part of a collection of oral history interviews conducted by the Chao Center for Asian Studies at Rice University. This collection includes audio recordings and transcripts of interviews with Asian Americans native to or living in Houston.Andy Chan was born in Queens, New York City in 1965. He moved to Houston in 1971 because of his father’s graphic artist career at Shell Oil Company. After studying environmental design at Texas A&M University for a year, Mr. Chan decided to go home to help his parents’ various businesses in the restaurant and graphics industries. He transferred to Texas Southern University and graduated while still working 40 hours a week in his father’s company. Eventually, Mr. Chan started his own business, Alpha Omega Graphics, which focused on the more cutting-edge side of desktop publishing.
After having children, Mr. Chan decided to sell his printing business and do more service within public education and the Houston School Districts. He served as PTO President for various elementary and middle schools, and currently serves on the District Advisory Committee. After a successful project renovating Fire Truck Park in Southside Place, Mr. Chan decided to run for City Council, and was also appointed Mayor Pro Tem in 2016 during Hurricane Harvey. This past May, he won the election for Mayor of the City of Southside Place. Mr. Chan is the first American Born Chinese to become Mayor in the state of Texas.
In this interview, Mr. Chan discusses his upbringing in New York City and Houston, his entrepreneurial endeavors throughout and after college, and his work in public education and service. He also discusses the importance of giving back to one’s community, his Asian-American identity, and his family
Sandy C. Marks Collection: A Finding Aid
No full textThis collection was processed by Lisa Grasso and Kristine Sjostedt, 2023-2024.The Sandy C. Marks Collection chronicles Dr. Marks’s career as a faculty member at UMass Chan Medical School
Dynamic Geometric Connectivity in the Plane with Constant Query Time
No full textWe present the first fully dynamic connectivity data structures for geometric intersection graphs achieving constant query time and sublinear amortized update time for many classes of geometric objects in 2D . Our data structures can answer connectivity queries between two objects, as well as "global" connectivity queries (e.g., deciding whether the entire graph is connected). Previously, the data structure by Afshani and Chan (ESA'06) achieved such bounds only in the special case of axis-aligned line segments or rectangles but did not work for arbitrary line segments or disks, whereas the data structures by Chan, Pătraşcu, and Roditty (FOCS'08) worked for more general classes of geometric objects but required n^{Ω(1)} query time and could not handle global connectivity queries.
Specifically, we obtain new data structures with O(1) query time and amortized update time near n^{4/5}, n^{7/8}, and n^{20/21} for axis-aligned line segments, disks, and arbitrary line segments respectively. Besides greatly reducing the query time, our data structures also improve the previous update times for axis-aligned line segments by Afshani and Chan (from near n^{10/11} to n^{4/5}) and for disks by Chan, Pătraşcu, and Roditty (from near n^{20/21} to n^{7/8})
- …
