Search results

21 – 30 of over 4000
Book part
Publication date: 2 November 2009

Ole Rummel

This chapter presents a model of distribution dynamics in the presence of measurement error in the underlying data. Studies of international growth convergence generally ignore…

Abstract

This chapter presents a model of distribution dynamics in the presence of measurement error in the underlying data. Studies of international growth convergence generally ignore the fact that per capita income data from the Penn World Table (PWT) are not only continuous variables but also measured with error. Together with short-time scale fluctuations, measurement error makes inferences potentially unreliable. When first-order, time-homogeneous Markov models are fitted to continuous data with measurement error, a bias towards excess mobility is introduced into the estimated transition probability matrix. This chapter evaluates different methods of accounting for this error. An EM algorithm is used for parameter estimation, and the methods are illustrated using data from the PWT Mark 6.1. Measurement error in income data is found to have quantitatively important effects on distribution dynamics. For instance, purging the data of measurement error reduces estimated transition intensities by between one- and four-fifths and more than halves the observed mobility of countries.

Details

Measurement Error: Consequences, Applications and Solutions
Type: Book
ISBN: 978-1-84855-902-8

Article
Publication date: 3 July 2020

Xiaoyun Ye and Myung-Mook Han

By using a new feature extraction method on the Cert data set and using a hidden Markov model (HMM) to model and analyze the behavior of users to distinguish whether the behavior…

Abstract

Purpose

By using a new feature extraction method on the Cert data set and using a hidden Markov model (HMM) to model and analyze the behavior of users to distinguish whether the behavior is normal within a continuous period.

Design/methodology/approach

Feature extraction of five parts of the time series by rules and sorting in chronological order. Use the obtained features to calculate the probability parameters required by the HMM model and establish a behavior model for each user. When the user has abnormal behavior, the model will return a very low probability value to distinguish between normal and abnormal information.

Findings

Generally, HMM parameters are obtained by supervised learning and unsupervised learning, but the hidden state cannot be clearly defined. When the hidden state is determined according to the data set, the accuracy of the model will be improved.

Originality/value

This paper proposes a new feature extraction method and analysis mode, which determines the shape of the hidden state according to the situation of the data set, making subsequent HMM modeling simple and efficient and in turn improving the accuracy of user behavior detection.

Details

Information & Computer Security, vol. 30 no. 1
Type: Research Article
ISSN: 2056-4961

Keywords

Article
Publication date: 30 March 2020

Hussaan Ahmad and Nasir Hayat

The purpose of this paper is to analyze the historical gas allocation pattern for seeking appropriate arrangement and utilization of potentially insufficient natural gas supply…

120

Abstract

Purpose

The purpose of this paper is to analyze the historical gas allocation pattern for seeking appropriate arrangement and utilization of potentially insufficient natural gas supply available in Pakistan up to 2030.

Design/methodology/approach

This study presents Markov chain-based modeling of historical gas allocation data followed by its validation through error evaluation. Structural prediction using classical Chapman–Kolmogorov method and varying-order polynomial regression in the historical transition matrices are presented.

Findings

Markov chain model reproduces the terminal state vector with 99.8 per cent accuracy, thus demonstrating its validity for capturing the history. Lower order polynomial regression results in better structural prediction compared with higher order ones in terms of closeness with Markov approach-based prediction.

Research limitations/implications

The data belongs to a certain geographic region with specific gas demand and supply profile. The proposition may be tested further by researchers to check the validity for other comparable structural predictions/analyses.

Practical implications

This study can facilitate policy-making in the field of natural gas allocation and management in Pakistan specifically and other comparable countries generally.

Originality/value

Two major literature gaps filled through this study are: first, Markov chain model becomes stationary when projected using Chapman–Kolmogorov relation in terms of a fixed, average transition matrix resulting in an equilibrium state after a finite number of future steps. Second, most of the previous studies analyze various gas consumption sectors individually, thus lacking integrated gas allocation policy.

Details

International Journal of Energy Sector Management, vol. 14 no. 5
Type: Research Article
ISSN: 1750-6220

Keywords

Article
Publication date: 25 February 2014

Qadeer Ahmed, Faisal I. Khan and Syed A. Raza

Asset intensive process industries are under immense pressure to achieve promised return on investments and production targets. This can be accomplished by ensuring the highest…

Abstract

Purpose

Asset intensive process industries are under immense pressure to achieve promised return on investments and production targets. This can be accomplished by ensuring the highest level of availability, reliability and utilization of the critical equipment in processing facilities. In order to achieve designed availability, asset characterization and maintainability play a vital role. The most appropriate and effective way to characterize the assets in a processing facility is based on risk and consequence of failure. The paper aims to discuss these issues.

Design/methodology/approach

In this research, a risk-based stochastic modeling approach using a Markov decision process is investigated to assess a processing unit's availability, which is referred as the risk-based availability Markov model (RBAMM). RBAMM will not only provide a realistic and effective way to identify critical assets in a plant but also a method to estimate availability for efficient planning purposes and resource optimization.

Findings

A unique risk matrix and methodology is proposed to determine the critical equipment with direct impact on the availability, reliability and safety of the process. A functional block diagram is then developed using critical equipment to perform efficient modeling. A Markov process is utilized to establish state diagrams and create steady-state equations to calculate the availability of the process. RBAMM is applied to natural gas absorption process to validate the proposed methodology. In the conclusion, other benefits and limitations of the proposed methodology are discussed.

Originality/value

A new risk-based methodology integrated with Markov model application of the methodology is demonstrated using a real-life application.

Details

International Journal of Quality & Reliability Management, vol. 31 no. 2
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 2 October 2017

Yen-Hao Hsieh and Wei-Ting Chen

The purpose of this study is to create a value variation measurement model to define the relationship among various roles in resource management within a service system; and…

363

Abstract

Purpose

The purpose of this study is to create a value variation measurement model to define the relationship among various roles in resource management within a service system; and divide value creation into two states (i.e. cocreation and codestruction) and use them as crucial indicators for value variation by adopting the service-dominant logic and using the Markov switching model.

Design/methodology/approach

This study proposed that variations in value are similar to changes in economy because both are abstract, indefinable and not easy to identify. Therefore, this study used the Markov switching model to define the state of value through value cocreation and codestruction; analyze value variations in a service system; and provide a numerical evaluation method by using the concept of probability to depict state transitions. In addition, open data from the Kaohsiung City Government’s 1999 call center were collected to address the aforementioned research objectives. The 1999 call center (service provider) offers citizens (customers) efficient consultant services to help them solve problems regarding the city government’s affairs or policies. Thus, this call center can be considered a complex service system.

Findings

This study revealed that the call center can utilize the analysis results of the Markov switching model on answer rates to predict service quality patterns. In addition, most first call resolution rates occurred under State 1 (value cocreation). To address problems caused by accidental or rare events, the call center should formulate policies to increase people and technical resources and improve service system effectiveness.

Originality/value

Enterprises currently focus on catering to customers’ needs and offering services through comprehensive service procedures to sustainably generate multiple values for customers, helping them to create values. Previous studies have mostly focused on analyzing the values of a service system and have failed to extensively explore actual value variations. Thus, the value variation measurement model proposed in the present study was able to analyze value variations of a set of call center data and illustrate value variations by using state transitions.

Details

Journal of Business & Industrial Marketing, vol. 32 no. 8
Type: Research Article
ISSN: 0885-8624

Keywords

Book part
Publication date: 9 September 2020

Yiying Cheng

Recently, there has been much progress in developing Markov switching stochastic volatility (MSSV) models for financial time series. Several studies consider various MSSV…

Abstract

Recently, there has been much progress in developing Markov switching stochastic volatility (MSSV) models for financial time series. Several studies consider various MSSV specifications and document superior forecasting power for volatility compared to the popular generalized autoregressive heteroscedasticity (GARCH) models. However, their application to option pricing remains limited, partially due to the lack of convenient closed-form option pricing formulas which integrate MSSV volatility estimates. We develop such a closed-form option pricing formula and the corresponding hedging strategy for a broad class of MSSV models. We then present an example of application to two of the most popular MSSV models: Markov switching multifractal (MSM) and component-driven regime switching (CDRS) models. Our results establish that these models perform well in one-day-ahead forecasts of option prices.

Details

Advances in Pacific Basin Business, Economics and Finance
Type: Book
ISBN: 978-1-83867-363-5

Keywords

Article
Publication date: 13 March 2017

Sameer Kumar, Nidhi Ghildayal and Neha Ghildayal

Urinary incontinence (UI) is a common chronic health condition, a problem specifically among elderly women that impacts quality of life negatively. However, UI is usually viewed…

Abstract

Purpose

Urinary incontinence (UI) is a common chronic health condition, a problem specifically among elderly women that impacts quality of life negatively. However, UI is usually viewed as likely result of old age, and as such is generally not evaluated or even managed appropriately. Many treatments are available to manage incontinence, such as bladder training and numerous surgical procedures such as Burch colposuspension and Sling for UI which have high success rates. The purpose of this paper is to analyze which of these popular surgical procedures for UI is effective.

Design/methodology/approach

This research employs randomized, prospective studies to obtain robust cost and utility data used in the Markov chain decision model for examining which of these surgical interventions is more effective in treating women with stress UI based on two measures: number of quality adjusted life years (QALY) and cost per QALY. Treeage Pro Healthcare software was employed in Markov decision analysis.

Findings

Results showed the Sling procedure is a more effective surgical intervention than the Burch. However, if a utility greater than certain utility value, for which both procedures are equally effective, is assigned to persistent incontinence, the Burch procedure is more effective than the Sling procedure.

Originality/value

This paper demonstrates the efficacy of a Markov chain decision modeling approach to study the comparative effectiveness analysis of available treatments for patients with UI, an important public health issue, widely prevalent among elderly women in developed and developing countries. This research also improves upon other analyses using a Markov chain decision modeling process to analyze various strategies for treating UI.

Details

International Journal of Health Care Quality Assurance, vol. 30 no. 2
Type: Research Article
ISSN: 0952-6862

Keywords

Article
Publication date: 3 May 2023

Fan Yang, Hao Chen and Shuai Xu

Quantitative reliability analysis can effectively identify the time the driving system needs to be maintained. Then, the potential safety problems can be found, and some…

Abstract

Purpose

Quantitative reliability analysis can effectively identify the time the driving system needs to be maintained. Then, the potential safety problems can be found, and some catastrophic failures can be effectively prevented. Therefore, this paper aims to evaluate the reliability of the switched reluctance generator (SRG) driving system.

Design/methodology/approach

In this paper, a method considering different thermal stresses and fault tolerance capacity is proposed to analyze the reliability of an SRG. A full-bridge power converter (FBPC) instead of the asymmetric half-bridge power converter (AHBPC) is adopted to drive the SRG system. First, the primary fault modes of the SRG system are introduced, and a fault criterion is proposed to determine whether the system fails. Second, the thermal circuit model of the converter is established to quickly and accurately obtain the junction temperature of the devices. At last, the Markov models of different levels are established to evaluate the reliability of the system.

Findings

The results show that the two-level Markov model is the most suitable when compared to the static model and the one-level Markov model.

Originality/value

The driving system of SRG will be more reliable after the reliability of the system is evaluated by the Markov model. At the same time, an FBPC is adopted to drive the SRG. The FBPCs have the advantages of fewer switching devices, higher integration and lower cost. The proposed driving strategy of the FBPC avoids the current reversal and the generation of dead zone time, which has the advantage of reliable operation. In addition, a precise thermal circuit model of the FBPC is proposed, and the junction temperature of each device can be obtained, respectively.

Details

Microelectronics International, vol. 40 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 1 December 1996

Brian Parker and David Caine

Gives the background to human resource planning (HRP) and argues that HRP tools are still an essential management requirement. Looks, therefore, to HRP tools that are not so…

3925

Abstract

Gives the background to human resource planning (HRP) and argues that HRP tools are still an essential management requirement. Looks, therefore, to HRP tools that are not so mathematically complex as to be of little use to the average practitioner. Provides an approach which harnesses modern spreadsheet technology to implement the previously esoteric tools of analysis ‐ “holonic modelling”. Holonic modelling recognizes that computer power and the flexibility of software packages allow problems to be structured in a flexible manner. Goes on to demonstrate the use of holonic modelling in the context of HRP.

Details

International Journal of Manpower, vol. 17 no. 8
Type: Research Article
ISSN: 0143-7720

Keywords

Article
Publication date: 3 January 2017

Rashid Mehmood, Royston Meriton, Gary Graham, Patrick Hennelly and Mukesh Kumar

The purpose of this paper is to advance knowledge of the transformative potential of big data on city-based transport models. The central question guiding this paper is: how could…

4113

Abstract

Purpose

The purpose of this paper is to advance knowledge of the transformative potential of big data on city-based transport models. The central question guiding this paper is: how could big data transform smart city transport operations? In answering this question the authors present initial results from a Markov study. However the authors also suggest caution in the transformation potential of big data and highlight the risks of city and organizational adoption. A theoretical framework is presented together with an associated scenario which guides the development of a Markov model.

Design/methodology/approach

A model with several scenarios is developed to explore a theoretical framework focussed on matching the transport demands (of people and freight mobility) with city transport service provision using big data. This model was designed to illustrate how sharing transport load (and capacity) in a smart city can improve efficiencies in meeting demand for city services.

Findings

This modelling study is an initial preliminary stage of the investigation in how big data could be used to redefine and enable new operational models. The study provides new understanding about load sharing and optimization in a smart city context. Basically the authors demonstrate how big data could be used to improve transport efficiency and lower externalities in a smart city. Further how improvement could take place by having a car free city environment, autonomous vehicles and shared resource capacity among providers.

Research limitations/implications

The research relied on a Markov model and the numerical solution of its steady state probabilities vector to illustrate the transformation of transport operations management (OM) in the future city context. More in depth analysis and more discrete modelling are clearly needed to assist in the implementation of big data initiatives and facilitate new innovations in OM. The work complements and extends that of Setia and Patel (2013), who theoretically link together information system design to operation absorptive capacity capabilities.

Practical implications

The study implies that transport operations would actually need to be re-organized so as to deal with lowering CO2 footprint. The logistic aspects could be seen as a move from individual firms optimizing their own transportation supply to a shared collaborative load and resourced system. Such ideas are radical changes driven by, or leading to more decentralized rather than having centralized transport solutions (Caplice, 2013).

Social implications

The growth of cities and urban areas in the twenty-first century has put more pressure on resources and conditions of urban life. This paper is an initial first step in building theory, knowledge and critical understanding of the social implications being posed by the growth in cities and the role that big data and smart cities could play in developing a resilient and sustainable transport city system.

Originality/value

Despite the importance of OM to big data implementation, for both practitioners and researchers, we have yet to see a systematic analysis of its implementation and its absorptive capacity contribution to building capabilities, at either city system or organizational levels. As such the Markov model makes a preliminary contribution to the literature integrating big data capabilities with OM capabilities and the resulting improvements in system absorptive capacity.

Details

International Journal of Operations & Production Management, vol. 37 no. 1
Type: Research Article
ISSN: 0144-3577

Keywords

21 – 30 of over 4000