Fast Hierarchical Clustering and Other Applications of Dynamic Closest Pairs

We develop data structures for dynamic closest pair problems with arbitrary distance functions, that do not necessarily come from any geometric structure on the objects. Based on a technique previously used by the author for Euclidean closest pairs, we show how to insert and delete objects from an n-object set, maintaining the closest pair, in O(n log^2 n) time per update and O(n) space. With quadratic space, we can instead use a quadtree-like structure to achieve an optimal time bound, O(n) per update. We apply these data structures to hierarchical clustering, greedy matching, and TSP heuristics, and discuss other potential applications in machine learning, Groebner bases, and local improvement algorithms for partition and placement problems. Experiments show our new methods to be faster in practice than previously used heuristics.Comment: 20 pages, 9 figures. A preliminary version of this paper appeared at the 9th ACM-SIAM Symp. on Discrete Algorithms, San Francisco, 1998, pp. 619-628. For source code and experimental results, see http://www.ics.uci.edu/~eppstein/projects/pairs

Old friends form alliance against podocytes

Wang and colleagues identify the activation of Wnt signaling as an important downstream event in transforming growth factor-β-mediated podocyte injury. Supported by other recent studies, canonical Wnt signaling is emerging as a critical stress pathway in podocytes and may be exploited for therapeutic strategies in the treatment of glomerulopathies

The family drug & alcohol court (FDAC) evaluation project

This report presents the findings from the evaluation of the first pilot Family Drug and Alcohol Court (FDAC) in Britain. FDAC is a new approach to care proceedings, in cases where parental substance misuse is a key element in the local authority decision to bring proceedings. It is being piloted at the Inner London Family Proceedings Court in Wells Street. Initially the pilot was to run for three years, to the end of December 2010, but is now to continue until March 2012. The work is co-funded by the Department for Education (formerly the Department for Children, Schools and Families), the Ministry of Justice, the Home Office, the Department of Health and the three pilot authorities (Camden, Islington and Westminster). The evaluation was conducted by a research team at Brunel University, with funding from the Nuffield Foundation and the Home Office. FDAC is a specialist court for a problem that is anything but special. Its potential to help break the inter-generational cycle of harm associated with parental substance misuse goes straight to the heart of public policy and professional practice. Parental substance misuse is a formidable social problem and a key factor in around a third of long-term cases in children’s services in some areas. It is a major risk factor for child maltreatment, family separation and offending in adults, and for poor educational performance and substance misuse by children and young people. The parents’ many difficulties create serious problems for their children and place major demands on health, welfare and criminal justice services. For these reasons, parental substance misuse is a cross-cutting government agenda. FDAC is distinctive because it is a court-based family intervention which aims to improve children’s outcomes by addressing the entrenched difficulties of their parents. It has been adapted to English law and practice from a model of family treatment drug courts that is used widely in the USA and is showing promising results with a higher number of cases where parents and children were able to remain together safely, and with swifter alternative placement decisions for children if parents were unable to address their substance misuse successfully. The catalysts for the FDAC pilot were the encouraging evidence from the USA and concerns about the response to parental substance misuse through ordinary care proceedings in England: poor coordination of adult and children’s services; late interventions to protect children; delays in reaching decisions in court; and soaring costs of proceedings, linked to the cost of expert evidence.The work is co-funded by the Department for Education (formerly the Department for Children, Schools and Families), the Ministry of Justice, the Home Office, the Department of Health and the three pilot authorities (Camden, Islington and Westminster).1 The evaluation was conducted by a research team at Brunel University, with funding from the Nuffield Foundation and the Home Office

Performance Seismic Design of the Retrofit of a University Library using Non-Conventional Methods

This research proposes a structural retrofit of a reinforced concrete building older than 50 years. The structural system is dual using frames and walls, having an area of 1980 m2 and 4 levels with a total height of 15.50 m. There are three unconventional methods to retrofit this infrastructure. The first is to install steel jackets with bolt anchors. The second methodology is through the use of jackets and anchors of Carbon Fiber Reinforced Polymers (CFRP). The third alternative is through reinforcement of walls with 2 diagonal struts made with CFRP sheets as struts, also installing CFRP anchors at each end of both struts to ensure that these sheets work up to their high levels of tension. These anchors together with the diagonal plates contribute to give ductility to the wall and in turn resist the effects of sliding at the base, a fault that is very common in rigid structures such as walls. Each unconventional reinforcement methodology used in this research is validated using laboratory tests results of reinforced columns and walls retrofitted with every of the three innovative methods. Nonlinear static analysis - Pushover of each alternative was performed and compared with the demand for the 1974 earthquake in Lima, scaling 3 seismic records to a PGA of 0.45g, which is the acceleration of design in Lima. It is shown that these proposals are effective in providing levels of shear base and displacement capacity in the inelastic design. For the 0.40mx0.80m columns, the results show that both reinforcements increase ductility by more than 10%; on the other hand, the proposal of reinforcement in the walls of 40cm thick, produced even better results increasing ductility by 100% and shear base by 100%

Competing For Loyalty: The Dynamics of Rallying Support

We consider a class of dynamic collective action problems in which either a single principal or two competing principals vie for the support of members of a group. We focus on the dynamic problem that emerges when agents negotiate and commit their support to principals sequentially. A danger for the agents in this context is that a principal may be able to succeed by exploiting competition among members of the group. Would agents benefit from introducing competition between opposing principals? We show that when principals? policies provide value to the agents, competition actually reduces agents? welfare

Pendeteksian Bit Error dalam Transmisi Data dengan Menerapkan Cyclic Redudancy Check

The communication path that will physically connect the two technologies conceptually works together such as cables. A special feature of a channel that resembles a cable is where the bits will be forwarded in the same order along with the bits sent. Data link layers have specific functions, this function includes starting from providing interfaces for services that are good for the network layer. Communication flows often make mistakes, sometimes having limited data rates and experiencing propagation delays other than zero between when bits are sent when the bit is received. This limitation is an implication of the importance of the efficiency of data transfer. Delivery of information in the telecommunications world will often occur errors in the data to be sent. This error is caused by a disturbance at the physical level, which is a disruption of the transmission line media, such as interference with electromagnetic radiation, cross communication, lightning or noise disturbance. This interference causes the information received does not match the information sent. The Cyclical Redundancy Check method, or CRC, is a method for handling error detection, this method uses binary numbers. The CRC data detection model is sent perframe consisting of a long row of bits for each frame