Super Efficiency Evaluations Based on Potential Slack

Super efficiency evaluations are introduced along the lines of the potential improvements approach in Bogetoft and Hougaard (1999). Both a reference selection and a related super efficiency index is defined. The new (potential slack) super efficiency index is compared to a Farrell-based super efficiency index (as in Andersen and Petersen 1993) with respect to convex envelopment technologies.super efficiency, potential slack, reference selection, efficiency index, DEA, Research Methods/ Statistical Methods,

Net Energy Index: A New Way To Measure Energy Efficient Buildings

Energy efficiency indexes are useful for providing tangible measurements of energy efficiency in buildings. Buildings use approximately 70% of all electricity in the USA. Using that energy efficiently has two primary benefits: limiting greenhouse gas emissions and reducing grid strain. Utilizing local renewable energy sources contributes to the same benefits. Currently, there is no index that considers renewable energy sources when measuring energy efficiency. Therefore, this paper proposes the Net Energy Index, which compares the net power usage of a building to the floor area of the building in order to determine energy efficiency. If renewable energy supplies power to a building, this index is not only useful and justified, but it is also practical through advances in energy meters

On inverted index compression for search engine efficiency

Efficient access to the inverted index data structure is a key aspect for a search engine to achieve fast response times to users’ queries . While the performance of an information retrieval (IR) system can be enhanced through the compression of its posting lists, there is little recent work in the literature that thoroughly compares and analyses the performance of modern integer compression schemes across different types of posting information (document ids, frequencies, positions). In this paper, we experiment with different modern integer compression algorithms, integrating these into a modern IR system. Through comprehensive experiments conducted on two large, widely used document corpora and large query sets, our results show the benefit of compression for different types of posting information to the space- and time-efficiency of the search engine. Overall, we find that the simple Frame of Reference compression scheme results in the best query response times for all types of posting information. Moreover, we observe that the frequency and position posting information in Web corpora that have large volumes of anchor text are more challenging to compress, yet compression is beneficial in reducing average query response times

The Relationship between Working Capital Management Efficiency and EBIT

This paper is aimed at analyzing the relationship between Working Capital Management Efficiency (WCME) and Earnings before Interest&Taxes (EBIT) of the Paper Industry in India during 1997–1998 to 2005–2006. Tomeasure the WCME three index values viz., Performance Index (PI), Utilization Index (UI), and Efficiency Index (EI) are computed, and are associated with explanatory variables, viz., Cash Conversion Cycle (CCC), Accounts Payable Days (APDAYS), Accounts Receivables Days (ARDAYS), Inventory Days (INVDAYS). Further, Fixed Financial Assets Ratio (FIXDFARA), Financial Debt Ratio (FINDBTRA) and Size (Natural log of Sales) are considered as control variables in the analysis, and are associated with the EBIT. The study reveals that the Paper Industry has managed the WC satisfactorily. The APDAYS has a significant (–)ve relationship with EBIT, which indicates that by deploying payment to suppliers they improve the EBIT. The Paper Industry in India performs remarkably well during the period, however, less profitable firms wait longer to pay their bills, and pursue a decrease in CCC.Working Capital Management Efficiency, Earnings before Interest and Taxes, Current Assets, Current Liabilities, Performance Index, Utilization Index, Efficiency Index

Measuring Tax Efficiency: A Tax Optimality Index

This paper introduces an index of tax optimality that measures the distance of a current tax structure from the optimal tax structure in the presence of public goods. In doing so, we derive a [0,1] number that reveals immediately how far the current tax configuration is from the optimal one and, thereby, the degree of efficiency of a tax system. We call this number the Tax Optimality Index. We show how the basic method can be altered in order to derive a revenue equivalent uniform tax, which measures the size of the public sector. A numerical example is used to illustrate the method developed.tax optimality index, excess burden, distance function

Online Self-Indexed Grammar Compression

Although several grammar-based self-indexes have been proposed thus far, their applicability is limited to offline settings where whole input texts are prepared, thus requiring to rebuild index structures for given additional inputs, which is often the case in the big data era. In this paper, we present the first online self-indexed grammar compression named OESP-index that can gradually build the index structure by reading input characters one-by-one. Such a property is another advantage which enables saving a working space for construction, because we do not need to store input texts in memory. We experimentally test OESP-index on the ability to build index structures and search query texts, and we show OESP-index's efficiency, especially space-efficiency for building index structures.Comment: To appear in the Proceedings of the 22nd edition of the International Symposium on String Processing and Information Retrieval (SPIRE2015

Efficiency and Productivity in the Spanish Food Distribution Sector

This study investigated the efficiency and productivity change of a sample of food distribution units (MERCAs) in Spain over the 1.997-1.999 period, applying non-parametric frontier methodology in a sales efficiency framework. We specified a mean sales model composed of two blocks of variables, the production block, and the marketing management block. Then we applied output oriented DEA methodology to perform the efficiency analysis, also taking into account the overall efficiency decomposition into pure and scale efficiency. The Malmquist index was calculated in order to analyse the components of the productivity change. The mean pure sales efficiency index was high, around 0.8, the mean scale index being 0,9. As appears from the results, six food distribution units were efficient, but some of the wholesale markets need to adapt their sales technology in order that their input bundle reaches a Most Productive Scale Size unit. We found no evidence of technical change during the period considered, but concluded that a notable scale efficiency change took place during the studied period. To summarise, we conclude that improvement in sales efficiency could be reached in the studied sector in both the pure and the scale efficiency.Efficiency, Productivity, DEA method, Malmquist index, Food Distribution Unit, Productivity Analysis,