Determining the impact regions of competing options in preference space

2017 ACM SIGMOD International Conference on Management of Data, SIGMOD 2017, Chicago, Illinois, USA, 14-19 May 2017In rank-aware processing, user preferences are typically represented by a numeric weight per data attribute, collectively forming a weight vector. The score of an option (data record) is defined as the weighted sum of its individual attributes. The highest-scoring options across a set of alternatives (dataset) are shortlisted for the user as the recommended ones. In that setting, the user input is a vector (equivalently, a point) in a d-dimensional preference space, where d is the number of data attributes. In this paper we study the problem of determining in which regions of the preference space the weight vector should lie so that a given option (focal record) is among the top-k score-wise. In effect, these regions capture all possible user profiles for which the focal record is highly preferable, and are therefore essential in market impact analysis, potential customer identification, profile-based marketing, targeted advertising, etc. We refer to our problem as k-Shortlist Preference Region identification (kSPR), and exploit its computational geometric nature to develop a framework for its efficient (and exact) processing. Using real and synthetic benchmarks, we show that our most optimized algorithm outperforms by three orders of magnitude a competitor we constructed from previous work on a different problem.Department of Computing2016-2017 > Academic research: refereed > Refereed conference paperbcw

Developing a conceptual model of marine farming in New Zealand

Survey and Geographic Information System (GIS) data analysis describes the relative influence of biophysical and human variables on site choices made by marine farmers in New Zealand. Community conflicts have grown in importance in determining farm location and different government planning strategies leave distinct signature patterns. Recent legislation empowers local governments to choose among three strategies for future regional aquaculture development. This paper suggests each strategy could result in different spatial outcomes. Simulation modelling of the type described here can provide a better understanding of farmer responses to management approaches and the range of futures that could result from planning choices made today

Who Benefits Whom in Daily Newspaper Markets?

Markets are generally thought to avoid problems, such as tyranny of the majority, that arise when allocation is accomplished through collective processes. Yet, with fixed costs, differentiated product markets deliver only products desired by substantial constituencies. When consumers share similar preferences, then additional consumers will bring forth additional products or improve the attributes or position of existing products and the consumers confer positive pecuniary preference externalities' on each other. However, if distinct groups of consumers have substantially different preferences, the groups can hurt each other through product markets. We document the pattern of preference externalities among black and white consumers of daily newspapers in the US. We find that, in their capacity as newspaper consumers, members of each group benefits themselves and either harm, or fail to benefit, each other through the product market. We document that product positioning provides the mechanism underlying our results. While Friedman (1962) argues that the use of political channels tends to strain the social cohesion essential for a stable society,' while, by contrast, widespread use of the market reduces the strain on the social fabric by rendering conformity unnecessary,' mounting evidence on media markets suggests otherwise.

Wright meets Markowitz: How standard portfolio theory changes when assets are technologies following experience curves

We consider how to optimally allocate investments in a portfolio of competing technologies using the standard mean-variance framework of portfolio theory. We assume that technologies follow the empirically observed relationship known as Wright's law, also called a "learning curve" or "experience curve", which postulates that costs drop as cumulative production increases. This introduces a positive feedback between cost and investment that complicates the portfolio problem, leading to multiple local optima, and causing a trade-off between concentrating investments in one project to spur rapid progress vs. diversifying over many projects to hedge against failure. We study the two-technology case and characterize the optimal diversification in terms of progress rates, variability, initial costs, initial experience, risk aversion, discount rate and total demand. The efficient frontier framework is used to visualize technology portfolios and show how feedback results in nonlinear distortions of the feasible set. For the two-period case, in which learning and uncertainty interact with discounting, we compare different scenarios and find that the discount rate plays a critical role

Economic Debate On Spatial Functional Linkages And Its Application to Key Spatial Development Challanges In Poland

This article presents a synthesis of today's world economic knowledge and the results of the analyses concerning: a) the nature of spatial functional linkages, including network structures, b) diversity of approaches concerning the application of spatial structures in the policies of encouraging the macro-level economic development of territorial units. This debate has been applied for discussing concrete dilemmas of spatial development of Poland i.e. the concept of polycentric metropolis. Such metropolis is a key part of the spatial development strategy for Poland i.e. Concept of National Spatial Development drawn up in 2008-2011 defining the objectives and priorities of the national spatial policy until 2030. Moreover, the article points to issues that require further research and deep analyses.spatial concentration, agglomeration patterns, spatial development, spatial policy

Theory vs Reality: Making Environmental Use Rights Work in New Zealand

The potential advantages in flexibility and efficiency of environmental use rights (such as permits and quotas) over prescriptive regulatory approaches have been well surveyed, and are being advocated in New Zealand now as a tool for achieving sustainable development. So why have they not been more widely adopted here? How can government help remove barriers and improve both economic and environmental outcomes in New Zealand? At the structural level the barriers tend to be well known, or presumed, as a lack of statutory frameworks or central government guidance, and information costs involved in defining the resource and in determining an appropriate rights framework to optimise its use. Even given these structural and technical barriers there remains the task of explaining why, since those barriers are not insuperable, little progress has occurred. Other factors include the extent to which such responsibility in New Zealand is delegated by central government, competing priorities for regional governments, lack of pressure on resources (eg; water in much of New Zealand), the difficulty of making contentious choices and strength of existing interests, reluctance to acknowledge any private rights to some resources, the relative ease of using existing regulatory tools, and low benefits relative to costs in small markets particularly where geographical distinctions exist such as for water and certain types of pollution. This suggests that the best focus for central government may be on better guidance, filling gaps in legislative frameworks, and providing or encouraging provision of the necessary institutions and systems in ways that allow economies of scope and scale. It is unclear how much scope there is for improvement but getting rid of unnecessary barriers, as long as it is done without unnecessary elaboration or restriction, will help secure whatever gains are out there to be had.Water, Property Rights, Transferability, Market Based Instruments

An Approach to Analyze Tradeoffs for Aerospace System Design and Operation

There are important tradeoffs that need to be considered for the design and operation of aerospace systems. In addition to tradeoffs, there may also be multiple stakeholders of interest to the system and each may have different preferences as to the balance amongst the tradeoffs under consideration. A tradeoff hyperspace is created when there are three or more tradeoff dimensions and this increases the challenge associated with resolving the hyperspace in order to determine the best design and operation of a system. The corresponding objectives of this research are to develop a framework to analyze tradeoff hyperspaces and to account for the preferences of multiple stakeholders in this framework.This work was supported by the National Aeronautics and Space Administration (NASA) under grant NRA- #NNX10AN92A (NASA Ames). The authors are grateful to Dr. Neil Y. Chen and Dr. Banavar Sridhar in the Aviation Systems Division at NASA Ames for their valuable guidance and feedback in managing this project

Solar thermal technology development: Estimated market size and energy cost savings. Volume 1: Executive summary

Estimated future energy cost savings associated with the development of cost-competitive solar thermal technologies (STT) are discussed. Analysis is restricted to STT in electric applications for 16 high-insolation/high-energy-price states. The fuel price scenarios and three 1990 STT system costs are considered, reflecting uncertainty over future fuel prices and STT cost projections. STT R&D is found to be unacceptably risky for private industry in the absence of federal support. Energy cost savings were projected to range from $0 to$10 billion (1990 values in 1981 dollars), dependng on the system cost and fuel price scenario. Normal R&D investment risks are accentuated because the Organization of Petroleum Exporting Countries (OPEC) cartel can artificially manipulate oil prices and undercut growth of alternative energy sources. Federal participation in STT R&D to help capture the potential benefits of developing cost-competitive STT was found to be in the national interest