Index-based Method Research Articles

Efficient Index-Based Snippet Generation

Ranked result lists with query-dependent snippets have become state of the art in text search. They are typically implemented by searching, at query time, for occurrences of the query words in the top-ranked documents. This document-based approach has three inherent problems: (i) when a document is indexed by terms which it does not contain literally (e.g., related words or spelling variants), localization of the corresponding snippets becomes problematic; (ii) each query operator (e.g., phrase or proximity search) has to be implemented twice, on the index side in order to compute the correct result set, and on the snippet-generation side to generate the appropriate snippets; and (iii) in a worst case, the whole document needs to be scanned for occurrences of the query words, which could be problematic for very long documents. We present a new index-based method that localizes snippets by information solely computed from the index and that overcomes all three problems. Unlike previous index-based methods, we show how to achieve this at essentially no extra cost in query processing time, by a technique we call operator inversion . We also show how our index-based method allows the caching of individual segments instead of complete documents, which enables a significantly larger cache hit-ratio as compared to the document-based approach. We have fully integrated our implementation with the CompleteSearch engine.

Enumeration of unlabeled uniform hypergraphs

We consider the enumeration problem of unlabeled hypergraphs by using Pólya’s counting theory and Burnside’s counting lemma. Instead of characterizing the cycle index of the permutation group acting on the edge set E, we treat each cycle in the cycle decomposition of a permutation ρ acting on E as an equivalence class (or transitive set) of E under the operation of the group generated by ρ. Compared to the cycle index-based method, our method is more effective to deal with the enumeration problem of hypergraphs. Using this method we establish an explicit counting formula for unlabeled k-uniform hypergraphs of order n, where k is an arbitrary integer with 1≤k≤n−1. Based on our counting formula, the asymptotic behavior for the number of unlabeled uniform hypergraphs is also analyzed.

Safety Assessment Curve (SAC) for inherent safety assessment in petrochemical industry

This paper highlights the development of a new numerical approach for safety assessment called Safety Assessment Curve (SAC). Most of the current methods for assessing inherent safety are index based method. Among the disadvantages of such methods is it employs scaling by dividing physical or chemical properties into subjective ranges and sudden jump in the score value at the sub-range boundary. This new technique can offer more useful features because aside from assessing the routes numerically, it could also graphically visualizes the effect of temperature, pressure, heat of reaction, process inventory, flammability, explosiveness, toxicity and reactivity in designing an inherently safer design for both, grassroot and retrofit cases in petrochemical industry without including subjective scaling and sudden jump in the score value. Due to page limitations, this paper will only discuss the development of SAC for chemical safety parameters. This novel technique can be used as an effective method to find the safer route among several number of alternatives for chemical synthesis or process retrofitting, besides highlighting the potential source of hazards in the process through numerical and graphical approach. The new SAC technique illustrated in this paper has been tested on methyl methacrylate manufacturing confirming its superiority in comparison to index-based method. Tertiery butyl alcohol (TBA) route has the lowest Chemical Safety Total Score suggesting it as the safest routes among the three routes for MMA production compared to acetone cyanohydrin (ACH) and ethylene via methyl propionate (C2/MP) based routes.

Efficient Detection for Top Part of Research Paper with Layout Index

The detection of elements in top part of research paper is the key problem in layout analysis, because these elements are often used as the search items by user. This paper provides a index-based method for auto detection of top part from research papers. Different from existing methods, an index is used for detecting items from top part of research paper. Experiments show the advantage of our method over existing methods, and future work is also described in the paper.

Robust landslide susceptibility analysis by combination of frequency ratio, heuristic GIS-methods and ground truth evaluation for a mountainous study area with poor data availability in the Three Gorges Reservoir area, PR China

Increasing number of geohazards, like mass movements, is one of the main environmental impacts following the impoundment of the Yangtze River and its tributaries due to the inventory of the Three Gorges Dam hydroelectric power plant. Although many cities and settlements are endangered, no detailed hazard mapping is possible because of the huge size of the affected area. Due to strongly limited data availability, a robust landslide susceptibility model was established exemplarily for the Xiangxi catchment as one of the main tributaries. The analyses were limited to translational, rotational and combined landslides in soft rock sediments because these represent the main types of mass movement activity in this area. The qualitative landslide susceptibility analysis was carried out by a combination of frequency ratio analyses and a heuristic iterative index-based method using a Geographical Information System. As conditioning factors, the parameters lithology, slope angle, -aspect, -curvature, drainage buffer distance and land use were applied. To improve the objectivity of the index-based method, the results of frequency ratio analyses were taken into consideration to assess the importance of each factor. Model verification and evaluation by ground truth enable to improve the model by iterative calculations and to identify the best performance model. Results indicate that 89 % of all known landslides are located within areas showing high susceptibility according to the best performance model. The study demonstrates that a rather simple but robust model achieves good results and is applicable for regional landslide susceptibility analyses in mountainous areas with poor data availability.

A NEAR-INFRARED SPECTROSCOPIC STUDY OF YOUNG FIELD ULTRACOOL DWARFS

We present a near-infrared (0.9-2.4 microns) spectroscopic study of 73 field ultracool dwarfs having spectroscopic and/or kinematic evidence of youth (~10-300 Myr). Our sample is composed of 48 low-resolution (R~100) spectra and 41 moderate-resolution spectra (R>~750-2000). First, we establish a method for spectral typing M5-L7 dwarfs at near-IR wavelengths that is independent of gravity. We find that both visual and index-based classification in the near-IR provide consistent spectral types with optical spectral types, though with a small systematic offset in the case of visual classification at J and K band. Second, we examine features in the spectra of ~10 Myr ultracool dwarfs to define a set of gravity-sensitive indices based on FeH, VO, K, Na and H-band continuum shape. We then create an index-based method for classifying the gravities of M6-L5 dwarfs that provides consistent results with gravity classifications from optical spectroscopy. Our index-based classification can distinguish between young and dusty objects. Guided by the resulting classifications, we propose a set of low-gravity spectral standards for the near-IR. Finally, we estimate the ages corresponding to our gravity classifications.

Fast Protein Binding Site Comparison via an Index-Based Screening Technology

We present TrixP, a new index-based method for fast protein binding site comparison and function prediction. TrixP determines binding site similarities based on the comparison of descriptors that encode pharmacophoric and spatial features. Therefore, it adopts the efficient core components of TrixX, a structure-based virtual screening technology for large compound libraries. TrixP expands this technology by new components in order to allow a screening of protein libraries. TrixP accounts for the inherent flexibility of proteins employing a partial shape matching routine. After the identification of structures with matching pharmacophoric features and geometric shape, TrixP superimposes the binding sites and, finally, assesses their similarity according to the fit of pharmacophoric properties. TrixP is able to find analogies between closely and distantly related binding sites. Recovery rates of 81.8% for similar binding site pairs, assisted by rejecting rates of 99.5% for dissimilar pairs on a test data set containing 1331 pairs, confirm this ability. TrixP exclusively identifies members of the same protein family on top ranking positions out of a library consisting of 9802 binding sites. Furthermore, 30 predicted kinase binding sites can almost perfectly be classified into their known subfamilies.

A method for identifying market power

An ability to exercise market power by suppliers may significantly reduce market efficiency in restructured electricity markets. Many studies have been performed to develop an effective tool to identify market power based on indices. Most often it is rather difficult to use an index-based method for real-time analysis. This paper provides a method to identify market power that can be used in real time. The purpose is to analyze price-dispatch sensitivity to determine whether there is a generator or a subset of generators that have the ability to increase its own price profitably. Case studies performed on a modified IEEE 118-bus system are presented.

Efficient grouping and ordering processing on XML data

Processing grouping operations on XML data has become an important research issue. In this article, we propose the notion of the structure group to represent a set of XML elements or attributes which are structure-related, and might correspond to the same set of answers. Such notion is used to design two indices. First, the group index is proposed to efficiently identify the structure group satisfying the value constraint. The value index can then retrieve the required value for a particular group. We also design the structure Grouping and Ordering Tree to represent the intermediate result in the properly nested and ordered structure, so that it can be easily transformed to the final result. A series of experiments have been performed, and the results show that the proposed index-based method is more efficient than the previous Scan approach, which scans the whole XML document and is based on the hashing technique.

Efficient Mining of Interesting Patterns in Large Biological Sequences

Pattern discovery in biological sequences (e.g., DNA sequences) is one of the most challenging tasks in computational biology and bioinformatics. So far, in most approaches, the number of occurrences is a major measure of determining whether a pattern is interesting or not. In computational biology, however, a pattern that is not frequent may still be considered very informative if its actual support frequency exceeds the prior expectation by a large margin. In this paper, we propose a new interesting measure that can provide meaningful biological information. We also propose an efficient index-based method for mining such interesting patterns. Experimental results show that our approach can find interesting patterns within an acceptable computation time.

Parameter Estimation and Vulnerability Assessment of Coastal Unconfined Aquifer to Saltwater Intrusion

The focus of the present work is to characterize a tropical, coastal aquifer and to carry out its vulnerability to saltwater intrusion using hydrogeological parameters. The characterization of the aquifer involves pumping tests, vertical electrical sounding, and water quality analysis carried out at 41 monitoring wells. The area under investigation lies between two tropical, seasonal, tidal rivers, i.e., Pavanje and Gurpur rivers, joining the Arabian on the west coast of India. The aquifer is predominantly shallow and unconfined, having moderate to good groundwater potential with transimissivity and specific yield ranging from 49.2 to 461:4 m2∕day and 0.00058 to 0.2805, respectively. The electrical resistivity tests indicated that the thickness of the aquifer ranges from 18 to 30 m. The study also investigates the saltwater affected areas in the region the vertical electrical sounding and water quality analysis. The resistivity results revealed several probable isolated saltwater intruded pockets in the region with resistivity less than 70 Ωm. From the salinity analysis of water, the locations that are affected during February to May (summer) and throughout the year are identified. The wells that are located close to the coast (< 350 m) and at lower elevations (well bottom 200 ppm) during the summer period from tidal inflow along the rivers. The water samples were also analyzed for chloride to bicarbonate ratios during December to May at all the monitoring wells and were found to be exceeding the allowable limit at several locations. The saltwater vulnerability maps are derived for the area by the index-based method using the hydrogeological parameters. The method was found to be effective while compared to the field observations. The results from the analysis indicate that the aquifer is medium to highly vulnerable to saltwater intrusion at majority of the locations. The impact of projected sea level rise by 0.25 and 0.50 m from the climate change is also assessed on the vulnerability of the region to saltwater intrusion. DOI: 10.1061/(ASCE)HE.1943-5584.0000524. © 2012 American Society of Civil Engineers

Evaluation of EHS hazard and sustainability metrics during early process design stages using principal component analysis

A principal component analysis (PCA) based methodology accounting for EHS hazard and sustainability metrics has been recently proposed in literature ( Srinivasan and Nhan, 2008) to deal with the subjective weighting problem of existing index-based methods. In this study we evaluate the potential use of the PCA-based method during early phases of process design in the problem of selection between various synthesis paths, also called chemical routes, for the production of chemical compounds. The study also focuses on the impact of the methodology settings on the obtained chemical route rankings and their interpretation. Two case studies have been performed regarding the production of 4-(2-methoxyethyl)-phenol (MEP) and methyl methacrylate (MMA) using fifteen different evaluation categories capturing various sustainability metrics. The PCA-based method identified the most promising chemical routes as well as the most important evaluation categories. The necessity for normalization of the raw data was demonstrated, without the method being very sensitive to the type of normalization. Moreover, the effect of the transition approach from chemical step to chemical route scores is discussed. The results of the PCA-based method are also compared with an index-based method ( Koller et al., 2000) sharing the same evaluation categories, as well as with other index-based frameworks in order to reveal the extent of similarities.

Combining Conservation Value, Vulnerability, and Effectiveness of Mitigation Actions in Spatial Conservation Decisions: An Application to Coastal Oil Spill Combating

Increasing oil transportation and severe oil accidents in the past have led to the development of various sensitivity maps in different countries all over the world. Often, however, the areas presented on the maps are far too large to be safeguarded with the available oil combating equipment and prioritization is required to decide which areas must be safeguarded. While oil booms can be applied to safeguard populations from a drifting oil slick, decision making on the spatial allocation of oil combating capacity is extremely difficult due to the lack of time, resources and knowledge. Since the operational decision makers usually are not ecologists, a useful decision support tool including ecological knowledge must be readily comprehensible and easy to use. We present an index-based method that can be used to make decisions concerning which populations of natural organisms should primarily be safeguarded from a floating oil slick with oil booms. The indices take into account the relative exposure, mortality and recovery potential of populations, the conservation value of species and populations, and the effectiveness of oil booms to safeguard different species. The method has been implemented in a mapping software that can be used in the Gulf of Finland (Baltic Sea) for operational oil combating. It could also be utilized in other similar conservation decisions where species with varying vulnerability, conservational value, and benefits received from the management actions need to be prioritized.

Inherent occupational health assessment during basic engineering stage

Each year more people die from work-related diseases than are killed in industrial accidents. Therefore it is essential to evaluate occupational health aspect during the process design. Early evaluation of safety, health, and environmental (SHE) performance is advantageous, since the opportunities to make the process inherently benign are greater and the cost therefore lower. The methods for occupational health assessments need to be tailored to specific design stages, since the data availability is changing as the design proceeds. In this paper, an index-based method called the Occupational Health Index (OHI) is presented for the basic engineering stage. The OHI is the final of the three methods in series proposed for health assessment in development and design stages. The OHI is based on the information available in piping and instrumentation diagrams (PIDs) and the plot plan. Four health aspects are considered; chronic inhalation risks to noncarcinogens and carcinogens, acute inhalation risk, and dermal/eye risk. The index is demonstrated on separation system of a toluene hydrodealkylation process. The assessment results allow the level of occupational health risks to be evaluated, the sources of exposures be detected, and corrective actions taken in a focused way.

Evaluating Environmental Impact in Water Distribution System Design

An index-based method for the evaluation of the environmental impact of water distribution systems is introduced. The method is developed according to a set of methodological criteria to assess the environmental effect of water networks. A number of environmental measures are incorporated into the index-based method to account for nonrenewable resource consumption, greenhouse gas emissions, and emissions to air, land, and water. The index-based method can be included into a multiobjective optimization program to find design solutions that minimize cost and environmental impact. The index-based method was applied to the design of a water transmission system over a 20-year design horizon. Design alternatives were compared on the basis of the environmental impact index and cost. For the system analyzed, results indicated that of the hydraulically feasible alternatives, the five most environmentally acceptable alternatives were the five most cost-effective alternatives. Results also showed that the environmental impact index is mainly influenced by pumping energy and partially influenced by pipe diameter selection.

Optimal waveband identification for estimation of leaf area index of paddy rice

The objectives of the study were to select suitable wavebands for rice leaf area index (LAI) estimation using the data acquired over a whole growing season, and to test the efficiency of the selected wavebands by comparing them with feature positions of rice canopy spectra. In this study, the field experiment in 2002 growing season was conducted at the experimental farm of Zhejiang University, Hangzhou, China. Measurements of hyperspectral reflectance (350 approximately 2500 nm) and corresponding LAI were made for a paddy rice canopy throughout the growing season. And three methods were employed to identify the optimal wavebands for paddy rice LAI estimation: correlation coefficient-based method, vegetation index-based method, and stepwise regression method. This research selected 15 wavebands in the region of 350~2 500 nm, which appeared to be the optimal wavebands for the paddy rice LAI estimation. Of the selected wavebands, the most frequently occurring wavebands were centered around 554, 675, 723, and 1 633 nm. They were followed by 444, 524, 576, 594, 804, 849, 974, 1 074, 1 219, 1 510, and 2 194 nm. Most of them made physical sense and had their counterparts in spectral known feature positions, which indicates the promising potential of the 15 selected wavebands for the retrieval of paddy rice LAI.

Reactive Market Power Analysis Using Must-Run Indices

This paper investigates the issues of reactive power must-run capacity in power system operations, hence in electricity markets. A must-run index-based method is proposed in the paper to measure the market power held by reactive power suppliers. The Nordic 32-bus system and the IEEE 118-bus system are used to test the proposed method. The market power holders of reactive power found using the proposed method are in accord with that found in the realistic Nordic system operation and in the existing analysis of IEEE 118-bus system. The paper identifies through must-run indices possible conditions that could lead to market power in the case of applying a bid structure within a market framework. Furthermore, market structure drawbacks can cause the appearance of market power even in a topologically ideal system.

Determination of influential factors and diagnostics using multivariate statistical relationships between variables and faults

This paper proposes a variable influence (VI) index-based on-line method for diagnosing discontinuous processes. The VI index is developed using the concept of contribution plots, and can be used to explain the influence of a process variable on a specific fault. The proposed method consists of two phases: off-line VI model-building and on-line diagnosis via VI index comparison. In the off-line VI model-building phase, the off-line VI model is constructed using off-line fault data and used as a reference model for the on-line diagnosis of a new batch. The on-line diagnosis phase is triggered by an out-of-control signal of a new batch. It calculates the VI index values for new process data available at that time, which are compared with the off-line VI index values of the off-line VI model stored in the data/model base. The proposed method has the advantage that it does not require any process knowledge of operators and can automatically select an assignable cause via the comparison of VI index values. A case study on a PVC batch process is conducted to demonstrate the diagnosis performance of the proposed method. The performance of the proposed method is also evaluated when an on-line mode is not considered in the proposed framework.

An Index-based Method to Manage the Tradeoff between Diversity and Commonality during Product Family Design

The competitiveness in today's market forces many companies to rethink the way they design products. Instead of developing one product at a time, many manufacturing companies are developing families of products to provide enough variety for the marketplace while keeping costs relatively low. Although the benefits of commonality are widely known, many companies are still not taking full advantage of it when developing new products or redesigning existing ones. One reason is the lack of appropriate methods and useful indices to assess a product family based on commonality and diversity. Although many component-based commonality indices have been proposed in the literature, they emphasize commonality at the expense of diversity in a product family. In this study, the design for commonality and diversity method based on two new commonality indices — the commonality diversity index and the comprehensive metric for commonality — is introduced to help designers manage the inherent tradeoff between commonality and diversity during the product family design process. To illustrate the proposed method, an example application involving a family of single-use cameras is presented. The proposed method provides useful recommendations at both the functional and component levels during product family design.

Managing Modularity and Commonality in Product and Process Development

Managing modularity and commonality throughout product and process development has been well recognized as crucial to producing a large variety of products while maintaining low costs and quick response to the market. In recent years we have seen growing consensus and an increasing number of publications related to modularity and commonality, as well as many endeavors in industrial applications. This special issue is dedicated to reporting recent advances in modularity and commonality research. Of particular interest is a comprehensive view of modularity and commonality, encompassing design, production, logistics, and organizational aspects. Based on thorough and strict peer reviews, a total of 10 papers were selected for publication from 48 submissions. These papers represent a snapshot of cutting-edge research and aim to disseminate recent developments in the field of managing modularity and commonality. The paper by Fixson, ‘Modularity and Commonality Research: Past Developments and Future Opportunities’, provides a comprehensive literature review. It substantially extends this editorial discussion on the status quo of approaches and techniques for managing modularity and commonality in product and process development. In the paper, each of the cited references is analyzed along the dimensions’ subject, effect, and research method. The subject of study involves the product, process, organization, and innovation, whereas the set of references indicate that a strong preference is geared towards the product. Also studied is a broad range of effects, with cost issues receiving the most attention. The survey reveals that a variety of research methods have been applied to the study of modularity and commonality, but the distribution of research methods differs substantially in modularity and commonality research. One important avenue for future research lies in studies that incorporate multiple effects of modularity and commonality on various players along the supply chain, that combine multiple research methods, and that follow systems over time. Holtta-Otto and de Weck, in their paper, ‘Degree of Modularity in Engineering Systems and Products with Technical and Business Constraints’, observe that modularity has many benefits, from cost savings due to increased commonality to efficient realization of a higher variety of products. In regard to full modularity, they show how engineering systems and products, whose design is heavily influenced by technical constraints, tend to exhibit rather integral architectures. On the basis of a binary design structure matrix representation of a system or product, they propose a metric of nonzero fraction capturing the sparsity of the interrelationships between components, along with a singular value modularity index indicating the degree of internal coupling. Empirical evidence is presented suggesting that the lightweight variant of the same product tends to be more integral, contributing to higher mass efficiency. Comparative studies of sparsity and modularity reveal that some products are inherently less modular than others due to technological factors. The paper by Thevenot, Simpson, Alizon, and Shooter, ‘An Index-Based Method to Manage the Tradeoff between Diversity and Commonality during Product Family Design’, emphasizes the commonality issue in product family design. This paper examines existing commonality indices with respect to the tradeoff between commonality and diversity inherent in product families. A design for commonality and diversity method is developed based on two new commonality indices: the commonality diversity index and the comprehensive metric for commonality. An example application involving a family of single-use cameras is reported, demonstrating decision making at both the functional and component levels during product family design. With focus on design reuse, Meehan, Duffy, and Whitfield, in their paper, ‘Supporting ‘‘Design for *Author to whom correspondence should be addressed. Email: jiao@pmail.ntv.edu.sg