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Article
Publication date: 1 June 2004

Alexandros Kallantzis and Sergios Lambropoulos

A scheduling method for determining the critical path in linear projects is presented, that takes into account maximum time and distance constraints in addition to the commonly…

2207

Abstract

A scheduling method for determining the critical path in linear projects is presented, that takes into account maximum time and distance constraints in addition to the commonly used minimum time and distance constraints. The maximum constraints, though often present in the specifications of a project, are not considered during the planning procedure, since no method existed to enable scheduling with them. The proposed method builds on the concept of the maximum constraints and expands on the necessary background for their implementation into the schedule. The introduced critical path algorithm allows for grouping linear activities into four categories regarding their critical status and their ability to influence project duration. The method is applied to a low‐pressure pipeline construction project and the results are presented.

Details

Engineering, Construction and Architectural Management, vol. 11 no. 3
Type: Research Article
ISSN: 0969-9988

Keywords

Book part
Publication date: 30 September 2014

Joachim Merz and Bettina Scherg

A growing polarization of society accompanied by an erosion of the middle class is receiving increasing attention in recent German economic and social policy discussion. Our study…

Abstract

A growing polarization of society accompanied by an erosion of the middle class is receiving increasing attention in recent German economic and social policy discussion. Our study contributes to this discussion in two ways: First, on a theoretical level we propose extended multidimensional polarization indices based on a constant elasticity of substitution (CES)-type well-being function and present a new measure to multidimensional polarization, the mean minimum polarization gap, 2DGAP. This polarization intensity measure provides transparency with regard to each single attribute, which is important for targeted policies, while at the same time respecting their interdependent relations. Second, in an empirical application, time is incorporated, in addition to the traditional income measure, as a fundamental resource for any activity. In particular, genuine personal leisure time will account for social participation in the sense of social inclusion/exclusion and Amartya Sen’s capability approach.

Instead of arbitrarily choosing the attribute parameters in the CES well-being function, the interdependent relations of time and income are evaluated by the German population. With the German Socio-Economic Panel (GSOEP) and detailed time use diary data from the German Time Use Surveys (GTUSs) 1991/1992 and 2001/2002, we quantify available and extended multidimensional polarization measures as well as our new approach to measuring the polarization of the working poor and affluent in Germany.

There are three prominent empirical results: Genuine personal leisure time in addition to income is an important and significant polarization attribute. Compensation is of economic and statistical significance. The new minimum 2DGAP approach reveals that multidimensional polarization increased in the 1990s in Germany.

Open Access
Article
Publication date: 5 September 2016

Qingyuan Wu, Changchen Zhan, Fu Lee Wang, Siyang Wang and Zeping Tang

The quick growth of web-based and mobile e-learning applications such as massive open online courses have created a large volume of online learning resources. Confronting such a…

3500

Abstract

Purpose

The quick growth of web-based and mobile e-learning applications such as massive open online courses have created a large volume of online learning resources. Confronting such a large amount of learning data, it is important to develop effective clustering approaches for user group modeling and intelligent tutoring. The paper aims to discuss these issues.

Design/methodology/approach

In this paper, a minimum spanning tree based approach is proposed for clustering of online learning resources. The novel clustering approach has two main stages, namely, elimination stage and construction stage. During the elimination stage, the Euclidean distance is adopted as a metrics formula to measure density of learning resources. Resources with quite low densities are identified as outliers and therefore removed. During the construction stage, a minimum spanning tree is built by initializing the centroids according to the degree of freedom of the resources. Online learning resources are subsequently partitioned into clusters by exploiting the structure of minimum spanning tree.

Findings

Conventional clustering algorithms have a number of shortcomings such that they cannot handle online learning resources effectively. On the one hand, extant partitional clustering methods use a randomly assigned centroid for each cluster, which usually cause the problem of ineffective clustering results. On the other hand, classical density-based clustering methods are very computationally expensive and time-consuming. Experimental results indicate that the algorithm proposed outperforms the traditional clustering algorithms for online learning resources.

Originality/value

The effectiveness of the proposed algorithms has been validated by using several data sets. Moreover, the proposed clustering algorithm has great potential in e-learning applications. It has been demonstrated how the novel technique can be integrated in various e-learning systems. For example, the clustering technique can classify learners into groups so that homogeneous grouping can improve the effectiveness of learning. Moreover, clustering of online learning resources is valuable to decision making in terms of tutorial strategies and instructional design for intelligent tutoring. Lastly, a number of directions for future research have been identified in the study.

Details

Asian Association of Open Universities Journal, vol. 11 no. 2
Type: Research Article
ISSN: 1858-3431

Keywords

Article
Publication date: 28 August 2009

Vassiliki A. Koutsonikola, Sophia G. Petridou, Athena I. Vakali and Georgios I. Papadimitriou

Web users' clustering is an important mining task since it contributes in identifying usage patterns, a beneficial task for a wide range of applications that rely on the web. The…

Abstract

Purpose

Web users' clustering is an important mining task since it contributes in identifying usage patterns, a beneficial task for a wide range of applications that rely on the web. The purpose of this paper is to examine the usage of Kullback‐Leibler (KL) divergence, an information theoretic distance, as an alternative option for measuring distances in web users clustering.

Design/methodology/approach

KL‐divergence is compared with other well‐known distance measures and clustering results are evaluated using a criterion function, validity indices, and graphical representations. Furthermore, the impact of noise (i.e. occasional or mistaken page visits) is evaluated, since it is imperative to assess whether a clustering process exhibits tolerance in noisy environments such as the web.

Findings

The proposed KL clustering approach is of similar performance when compared with other distance measures under both synthetic and real data workloads. Moreover, imposing extra noise on real data, the approach shows minimum deterioration among most of the other conventional distance measures.

Practical implications

The experimental results show that a probabilistic measure such as KL‐divergence has proven to be quite efficient in noisy environments and thus constitute a good alternative, the web users clustering problem.

Originality/value

This work is inspired by the usage of divergence in clustering of biological data and it is introduced by the authors in the area of web clustering. According to the experimental results presented in this paper, KL‐divergence can be considered as a good alternative for measuring distances in noisy environments such as the web.

Details

International Journal of Web Information Systems, vol. 5 no. 3
Type: Research Article
ISSN: 1744-0084

Keywords

Open Access
Article
Publication date: 24 December 2021

Lishengsa Yue, Mohamed Abdel-Aty and Zijin Wang

This study aims to evaluate the influence of connected and autonomous vehicle (CAV) merging algorithms on the driver behavior of human-driven vehicles on the mainline.

Abstract

Purpose

This study aims to evaluate the influence of connected and autonomous vehicle (CAV) merging algorithms on the driver behavior of human-driven vehicles on the mainline.

Design/methodology/approach

Previous studies designed their merging algorithms mostly based on either the simulation or the restricted field testing, which lacks consideration of realistic driving behaviors in the merging scenario. This study developed a multi-driver simulator system to embed realistic driving behavior in the validation of merging algorithms.

Findings

Four types of CAV merging algorithms were evaluated regarding their influences on driving safety and driving comfort of the mainline vehicle platoon. The results revealed significant variation of the algorithm influences. Specifically, the results show that the reference-trajectory-based merging algorithm may outperform the social-psychology-based merging algorithm which only considers the ramp vehicles.

Originality/value

To the best of the authors’ knowledge, this is the first time to evaluate a CAV control algorithm considering realistic driver interactions rather than by the simulation. To achieve the research purpose, a novel multi-driver driving simulator was developed, which enables multi-drivers to simultaneously interact with each other during a virtual driving test. The results are expected to have practical implications for further improvement of the CAV merging algorithm.

Details

Journal of Intelligent and Connected Vehicles, vol. 5 no. 1
Type: Research Article
ISSN: 2399-9802

Keywords

Article
Publication date: 1 January 1989

EDIE M. RASMUSSEN and PETER WILLETT

The implementation of hierarchic agglomerative methods of cluster anlaysis for large datasets is very demanding of computational resources when implemented on conventional…

Abstract

The implementation of hierarchic agglomerative methods of cluster anlaysis for large datasets is very demanding of computational resources when implemented on conventional computers. The ICL Distributed Array Processor (DAP) allows many of the scanning and matching operations required in clustering to be carried out in parallel. Experiments are described using the single linkage and Ward's hierarchical agglomerative clustering methods on both real and simulated datasets. Clustering runs on the DAP are compared with the most efficient algorithms currently available implemented on an IBM 3083 BX. The DAP is found to be 2.9–7.9 times as fast as the IBM, the exact degree of speed‐up depending on the size of the dataset, the clustering method, and the serial clustering algorithm that is used. An analysis of the cycle times of the two machines is presented which suggests that further, very substantial speed‐ups could be obtained from array processors of this type if they were to be based on more powerful processing elements.

Details

Journal of Documentation, vol. 45 no. 1
Type: Research Article
ISSN: 0022-0418

Article
Publication date: 1 August 2016

Ye Li, Shanli Zhu and San-dang Guo

The purpose of this paper is to propose the grey target decision method based on three-parameter interval grey number for dealing with multi-attribute decision-making problems…

Abstract

Purpose

The purpose of this paper is to propose the grey target decision method based on three-parameter interval grey number for dealing with multi-attribute decision-making problems under uncertain environment.

Design/methodology/approach

First, the kernel and ranking method of three-parameter interval grey number are defined, which is the basis of determining the positive and negative bull’s-eye. Next, a new distance measure of three-parameter interval grey number is defined in view of the importance of the “center of gravity” point. Furthermore, a new comprehensive bull’s-eye distance is proposed based on the kernel which integrates the distance between different attributes to the positive and negative bull’s-eye. Then attribute weights are obtained by comprehensive bull’s-eye distance minimum and grey entropy maximization.

Findings

The paper provides a grey target decision method based on three-parameter interval grey number and example analysis shows that the method proposed in this paper is more reasonable and effective.

Research limitations/implications

If we have a better understanding of the distribution characteristics of three-parameter interval grey number, it is possible to have a more reasonable measure of the distance of three-parameter interval grey number.

Practical implications

The paper provides a grey target decision method, which can help decision maker deal with multi-attribute decision-making problems under uncertain environment.

Originality/value

This paper proposed the kernel and ranking method of three-parameter interval grey number, and defined a new distance measure of three-parameter interval grey number and proposed a new comprehensive bull’s-eye distance, Furthermore, this paper structured a grey target decision method based on three-parameter interval grey number.

Details

Grey Systems: Theory and Application, vol. 6 no. 2
Type: Research Article
ISSN: 2043-9377

Keywords

Article
Publication date: 11 March 2014

Zulkifli Mohamed, Mitsuki Kitani and Genci Capi

– The purpose of this paper is to compare the performance of the robot arm motion generated by neural controllers in simulated and real robot experiments.

Abstract

Purpose

The purpose of this paper is to compare the performance of the robot arm motion generated by neural controllers in simulated and real robot experiments.

Design/methodology/approach

The arm motion generation is formulated as an optimization problem. The neural controllers generate the robot arm motion in dynamic environments optimizing three different objective functions; minimum execution time, minimum distance and minimum acceleration. In addition, the robot motion generation in the presence of obstacles is also considered.

Findings

The robot is able to adapt its arm motion generation based on the specific task, reaching the goal position in simulated and experimental tests. The same neural controller can be employed to generate the robot motion for a wide range of initial and goal positions.

Research limitations/implications

The motion generated yield good results in both simulation and experimental environments.

Practical implications

The robot motion is generated based on three different objective functions that are simultaneously optimized. Therefore, the humanoid robot can perform a wide range of tasks in real-life environments, by selecting the appropriate motion.

Originality/value

A new method for adaptive arm motion generation of a mobile humanoid robot operating in dynamic human and industrial environments.

Details

Industrial Robot: An International Journal, vol. 41 no. 2
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 1 January 2006

Yueqi Zhong and Bugao Xu

This paper presents methods and algorithms to automatically segment and measure the human body.

1890

Abstract

Purpose

This paper presents methods and algorithms to automatically segment and measure the human body.

Design/methodology/approach

In the segmentation procedure, two different methods are designed to find the crotch point for the situation of non‐contacted thigh and contacted thigh, respectively. Three different methods: minimum distance algorithm, minimum inclination angle algorithm, and directional neighbor identification algorithm are introduced to search the branching points or triangle. In the body measurement procedure, a pre‐sorted circling method is designed for circumference measurement, and the basic principle of landmark acquisition has been discussed. These techniques are validated via testing over different type of scanned model.

Findings

The results of automatic segmentation and body measurement have verified that our methods are efficient and versatile in processing different type of scanned body.

Research limitations/implications

The accurate and automatic locating of wrist, ankle and knees contour can be more difficult than it appears to be.

Practical implications

The main usage of scanned body in our research is for 3D garment try‐on.

Originality/value

This paper introduces the methods for crotch identification, and the methods including minimum distance algorithm, minimum inclination angle algorithm, and directional neighbor identification algorithm for human body segmentation. It also explains the fundamental measuring techniques, and outlines the results of using these techniques in segmentation and measurement.

Details

International Journal of Clothing Science and Technology, vol. 18 no. 1
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 24 May 2013

Shouzhen Zeng

The purpose of this paper is to present a new decision making technique called the uncertain induced Minkowski OWA distance (UIMOWAD) operator.

Abstract

Purpose

The purpose of this paper is to present a new decision making technique called the uncertain induced Minkowski OWA distance (UIMOWAD) operator.

Design/methodology/approach

The developed UIMOWAD operator is a new aggregation operator that uses the IOWA operator, the Minkowski distance and interval numbers. It is an extension of the IMOWAD operator that uses uncertain information in the aggregation represented in the form of interval numbers.

Findings

The UIMOWAD operator is very suitable to deal with complex reordering processes that represent a wide range of factors in an uncertain environment that can be assessed with interval numbers.

Research limitations/implications

Clearly, this paper is devoted to the OWA operator and uncertain theory.

Practical implications

The UIMOWAD operator is applicable in a wide range of situations such as decision‐making, statistics, engineering and economics.

Originality/value

This paper fulfils an identified need to study how to make a decision according to expert's interest in uncertain environment.

Details

Kybernetes, vol. 42 no. 5
Type: Research Article
ISSN: 0368-492X

Keywords

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