The component model for elementary landscapes and partial neighborhoods

Theoretical Computer Science, 545, (2014), pp. 59-75Local search algorithms exploit moves on an adjacency graph of the search space. An “elementary landscape” exists if the objective function f is an eigenfunction of the Laplacian of the graph induced by the neighborhood operator; this allows various statistics about the neighborhood to be computed in closed form. A new component based model makes it relatively simple to prove that certain types of landscapes are elementary. The traveling salesperson problem, weighted graph (vertex) coloring and the minimum graph bisection problem yield elementary landscapes under commonly used local search operators. The component model is then used to efficiently compute the mean objective function value over partial neighborhoods for these same problems. For a traveling salesperson problem over n cities, the 2-opt neighborhood can be decomposed into ⌊n/2−1⌋ partial neighborhoods. For graph coloring and the minimum graph bisection problem, partial neighborhoods can be used to focus search on those moves that are capable of producing a solution with a strictly improving objective function value.Air Force Office of Scientific Research, Air Force Materiel Command, USAF, under grant number FA9550-08-1-0422

The power of place in disaster recovery: Heritage-based practice in the post-Matthew landscape of Princeville, North Carolina

This article examines shortcomings and possible improvements to standard post-disaster recovery processes through the lens of recovery in Princeville, North Carolina, the oldest black town in the United States. Princeville has faced existential challenges since it was settled in the Tar River floodplain in 1865, most recently in 2016 with flooding caused by Hurricane Matthew. The article describes the power of place attachment and the trauma caused by place-based disaster. It points out that significant rebuilding typically begins a full three years into a standard recovery timeline. And it argues that in the midst of that recovery process, our identification of significant landscapes—i.e., landscapes worth protecting and restoring—is too heavily driven by the object-oriented standards of traditional historic preservation. This article describes work coordinated by North Carolina State University design faculty in partnership with the town of Princeville to supplement abstract, top-down recovery processes with practice that is landscape-based and interactive, that marks histories and establishes concrete symbols of ongoing life, and that promises to help displaced communities to build social-ecological resilience and to heal. This type of work will only become more vital as more communities face climate-induced disasters and the need to rebuild. By describing the impetus and possible impact of NC State’s post-disaster work with Princeville, this article seeks to start a conversation about how our recovery processes can better recognize the power of place and the role of the land as a vehicle for resilience and healing

Elementary Landscape Decomposition of the Hamiltonian Path Optimization Problem

There exist local search landscapes where the evaluation function is an eigenfunction of the graph Laplacian that corresponds to the neighborhood structure of the search space. Problems that dis- play this structure are called “Elementary Landscapes” and they have a number of special mathematical properties. The problems that are not elementary landscapes can be decomposed in a sum of elementary ones. This sum is called the elementary landscape decomposition of the problem. In this paper, we provide the elementary landscape decomposi- tion for the Hamiltonian Path Optimization Problem under two different neighborhoods.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Quasi-elementary Landscapes and Superpositions of Elementary Landscapes

Whitley, D., & Chicano F. (2012). Quasi-elementary Landscapes and Superpositions of Elementary Landscapes. (Hamadi, Y., & Schoenauer M., Ed.).Learning and Intelligent Optimization - 6th International Conference, LION 6, Paris, France, January 16-20, 2012, Revised Selected Papers. 277–291.There exist local search landscapes where the evaluation function is an eigenfunction of the graph Laplacian that corresponds to the neighborhood structure of the search space. Problems that display this structure are called “Elementary Landscapes” and they have a number of special mathematical properties. The term “Quasi-elementary landscapes” is introduced to describe landscapes that are “almost” elementary; in quasi-elementary landscapes there exists some efficiently computed “correction” that captures those parts of the neighborhood structure that deviate from the normal structure found in elementary landscapes. The “shift” operator, as well as the “3-opt” operator for the Traveling Salesman Problem landscapes induce quasi-elementary landscapes. A local search neighborhood for the Maximal Clique problem is also quasi-elementary. Finally, we show that landscapes which are a superposition of elementary landscapes can be quasi-elementary in structure.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Air Force Office of Scientific Research, Air Force Materiel Command, USAF, under grant number FA9550-11-1-0088. Spanish Ministry of Science and Innovation and FEDER under contract TIN2008-06491-C04-01 (the M∗ project). Andalusian Government under contract P07-TIC-03044 (DIRICOM project)

FUNCTIONAL BARRIERS IN IASI URBAN AREA

The forced industrialisation of cities resulted in the construction of giant sites in outlying areas. December 1989 triggered the decline of industrial activities, wich could not be sustained any longer. Gradually, industrial halls have been abandoned, turning into ghosts of past glory, „black spots” that visually pollute the city’s image. The article highlitghts the tendency of these abandoned spaces to become true functional barriers. Occupying large spaces, the former industrial units are a barrier to communication (moving obstacle) and for the development of certain areas. Perceveid as dangerous places, with a low security level, the problem of abandoned areas would be a subject for the terriorial marketing strategies. in this regard, putting into value the results of a field survey, the article studies the perception of the urban brownfields, applied for Ia?i as a case study.industrial zone, functional barrier, communication, perception, image.

Some additional properties of elementary landscapes

AbstractIn this work, we derive a general class of multistep composite elementary landscapes and present the first non-trivial lower (upper) bounds on local minima (maxima) associated with elementary landscapes

Wound/ Healing/ Scar: an Urban School

The American city contains large brownfields and urban wastelands, remnants of our industrial past. The sprawling and unchecked development of our cities combined with short-sighted zoning laws and vast industrial infrastructure created these gashes in the post-industrial landscape. Old rail yards, industrial processes, abandoned buildings, interstates, and abandoned riverfronts and wharves wound the urban landscape, and the reactionary response is to clear the site and start over. Yet as Carol Burns states, there is no such thing as a “clear” site- all sites contain permanent imprints of past and present events. This thesis posits that architecture possesses the power to heal the wounds left by these damaging actions by constructing on the site buildings that reconnect the old and the new in a manner that regenerates the site. These constructed sites begin to heal the wound while leaving an architectural “scar” on the site. This thesis addresses the social and ecological wounds left on the city of Knoxville by the interstate system. I will demonstrate how architectural scars can activate the residual spaces around and below the interstates that once divided the city, re-stitching the urban landscape. The program explores the potential for healing the social and ecological wounds through the insertion of a community elementary and middle school as a scar