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Article
Publication date: 15 December 2017

Maxim A. Dulebenets

The volumes of international containerized trade substantially increased over the past years. In the meantime, marine container terminal (MCT) operators are facing congestion…

1097

Abstract

Purpose

The volumes of international containerized trade substantially increased over the past years. In the meantime, marine container terminal (MCT) operators are facing congestion issues at their terminals because of the increasing number of large-size vessels, the lack of innovative technologies and advanced handling equipment and the inability of proper scheduling of the available resources. This study aims to propose a novel memetic algorithm with a deterministic parameter control to facilitate the berth scheduling at MCTs and minimize the total vessel service cost.

Design/methodology/approach

A local search heuristic, which is based on the first-come-first-served policy, is applied at the chromosomes and population initialization stage within the developed memetic algorithm (MA). The deterministic parameter control strategy is implemented for a custom mutation operator, which alters the mutation rate values based on the piecewise function throughout the evolution of the algorithm. Performance of the proposed MA is compared with that of the alternative solution algorithms widely used in the berth scheduling literature, including a MA that does not apply the deterministic parameter control strategy, typical evolutionary algorithm, simulated annealing and variable neighborhood search.

Findings

Results demonstrate that the developed MA with a deterministic parameter control can obtain superior berth schedules in terms of the total vessel service cost within a reasonable computational time. Furthermore, greater cost savings are observed for the cases with high demand and low berthing capacity at the terminal. A comprehensive analysis of the convergence patterns indicates that introduction of the custom mutation operator with a deterministic control for the mutation rate value would provide more efficient exploration and exploitation of the search space.

Research limitations/implications

This study does not account for uncertainty in vessel arrivals. Furthermore, potential changes in the vessel handling times owing to terminal disruptions are not captured.

Practical implications

The developed solution algorithm can serve as an efficient planning tool for MCT operators and assist with efficient berth scheduling for both discrete and continuous berthing layout cases.

Originality/value

The majority of studies on berth scheduling rely on the stochastic search algorithms without considering the specific problem properties and applying the guided search heuristics. Unlike canonical evolutionary algorithms, the developed algorithm uses a local search heuristic for the chromosomes and population initialization and adjusts the mutation rate values based on a deterministic parameter control strategy for more efficient exploration and exploitation of the search space.

Details

Maritime Business Review, vol. 2 no. 4
Type: Research Article
ISSN: 2397-3757

Keywords

Content available
Article
Publication date: 3 December 2019

Masoud Kavoosi, Maxim A. Dulebenets, Olumide Abioye, Junayed Pasha, Oluwatosin Theophilus, Hui Wang, Raphael Kampmann and Marko Mikijeljević

Marine transportation has been faced with an increasing demand for containerized cargo during the past decade. Marine container terminals (MCTs), as the facilities for connecting…

1552

Abstract

Purpose

Marine transportation has been faced with an increasing demand for containerized cargo during the past decade. Marine container terminals (MCTs), as the facilities for connecting seaborne and inland transportation, are expected to handle the increasing amount of containers, delivered by vessels. Berth scheduling plays an important role for the total throughput of MCTs as well as the overall effectiveness of the MCT operations. This study aims to propose a novel island-based metaheuristic algorithm to solve the berth scheduling problem and minimize the total cost of serving the arriving vessels at the MCT.

Design/methodology/approach

A universal island-based metaheuristic algorithm (UIMA) was proposed in this study, aiming to solve the spatially constrained berth scheduling problem. The UIMA population was divided into four sub-populations (i.e. islands). Unlike the canonical island-based algorithms that execute the same metaheuristic on each island, four different population-based metaheuristics are adopted within the developed algorithm to search the islands, including the following: evolutionary algorithm (EA), particle swarm optimization (PSO), estimation of distribution algorithm (EDA) and differential evolution (DE). The adopted population-based metaheuristic algorithms rely on different operators, which facilitate the search process for superior solutions on the UIMA islands.

Findings

The conducted numerical experiments demonstrated that the developed UIMA algorithm returned near-optimal solutions for the small-size problem instances. As for the large-size problem instances, UIMA was found to be superior to the EA, PSO, EDA and DE algorithms, which were executed in isolation, in terms of the obtained objective function values at termination. Furthermore, the developed UIMA algorithm outperformed various single-solution-based metaheuristic algorithms (including variable neighborhood search, tabu search and simulated annealing) in terms of the solution quality. The maximum UIMA computational time did not exceed 306 s.

Research limitations/implications

Some of the previous berth scheduling studies modeled uncertain vessel arrival times and/or handling times, while this study assumed the vessel arrival and handling times to be deterministic.

Practical implications

The developed UIMA algorithm can be used by the MCT operators as an efficient decision support tool and assist with a cost-effective design of berth schedules within an acceptable computational time.

Originality/value

A novel island-based metaheuristic algorithm is designed to solve the spatially constrained berth scheduling problem. The proposed island-based algorithm adopts several types of metaheuristic algorithms to cover different areas of the search space. The considered metaheuristic algorithms rely on different operators. Such feature is expected to facilitate the search process for superior solutions.

Content available
Article
Publication date: 23 November 2021

Phuc Bao Uyen Nguyen

The purpose is to develop search and detection strategies that maximize the probability of detection of mine-like objects.

Abstract

Purpose

The purpose is to develop search and detection strategies that maximize the probability of detection of mine-like objects.

Design/methodology/approach

The author have developed a methodology that incorporates variational calculus, number theory and algebra to derive a globally optimal strategy that maximizes the expected probability of detection.

Findings

The author found a set of look angles that globally maximize the probability of detection for a general class of mirror symmetric targets.

Research limitations/implications

The optimal strategies only maximize the probability of detection and not the probability of identification.

Practical implications

In the context of a search and detection operation, there is only a limited time to find the target before life is lost; hence, improving the chance of detection will in real terms be translated into the difference between success or failure, life or death. This rich field of study can be applied to mine countermeasure operations to make sure that the areas of operations are free of mines so that naval operations can be conducted safely.

Originality/value

There are two novel elements in this paper. First, the author determine the set of globally optimal look angles that maximize the probability of detection. Second, the author introduce the phenomenon of concordance between sensor images.

Details

Journal of Defense Analytics and Logistics, vol. 5 no. 2
Type: Research Article
ISSN: 2399-6439

Keywords

Open Access
Article
Publication date: 6 February 2024

Luuk Mandemakers, Eva Jaspers and Tanja van der Lippe

Employees facing challenges in their careers – i.e. female, migrant, elderly and lower-educated employees – might expect job searches to have a low likelihood of success and might…

Abstract

Purpose

Employees facing challenges in their careers – i.e. female, migrant, elderly and lower-educated employees – might expect job searches to have a low likelihood of success and might therefore more often stay in unsatisfactory positions. The goal of this study is to discover inequalities in job mobility for these employees.

Design/methodology/approach

We rely on a large sample of Dutch public sector employees (N = 30,709) and study whether employees with challenges in their careers are hampered in translating job dissatisfaction into job searches. Additionally, we assess whether this is due to their perceptions of labor market alternatives.

Findings

Findings show that non-Western migrant, elderly and lower-educated employees are less likely to act on job dissatisfaction than their advantaged counterparts, whereas women are more likely than men to do so. Additionally, we find that although they perceive labor market opportunities as limited, this does not affect their propensity to search for different jobs.

Originality/value

This paper is novel in discovering inequalities in job mobility by analyzing whether employees facing challenges in their careers are less likely to act on job dissatisfaction and therefore more likely to remain in unsatisfactory positions.

Details

Equality, Diversity and Inclusion: An International Journal, vol. 43 no. 9
Type: Research Article
ISSN: 2040-7149

Keywords

Open Access
Article
Publication date: 16 January 2024

Ville Jylhä, Noora Hirvonen and Jutta Haider

This study addresses how algorithmic recommendations and their affordances shape everyday information practices among young people.

Abstract

Purpose

This study addresses how algorithmic recommendations and their affordances shape everyday information practices among young people.

Design/methodology/approach

Thematic interviews were conducted with 20 Finnish young people aged 15–16 years. The material was analysed using qualitative content analysis, with a focus on everyday information practices involving online platforms.

Findings

The key finding of the study is that the current affordances of algorithmic recommendations enable users to engage in more passive practices instead of active search and evaluation practices. Two major themes emerged from the analysis: enabling not searching, inviting high trust, which highlights the how the affordances of algorithmic recommendations enable the delegation of search to a recommender system and, at the same time, invite trust in the system, and constraining finding, discouraging diversity, which focuses on the constraining degree of affordances and breakdowns associated with algorithmic recommendations.

Originality/value

This study contributes new knowledge regarding the ways in which algorithmic recommendations shape the information practices in young people's everyday lives specifically addressing the constraining nature of affordances.

Details

Journal of Documentation, vol. 80 no. 7
Type: Research Article
ISSN: 0022-0418

Keywords

Open Access
Article
Publication date: 16 October 2023

Koraljka Golub, Jenny Bergenmar and Siska Humelsjö

This article aims to help ensure high-quality subject access to Swedish lesbian, gay, bisexual, transgender, queer and intersexual (LGBTQI) fiction, and aims to identify…

Abstract

Purpose

This article aims to help ensure high-quality subject access to Swedish lesbian, gay, bisexual, transgender, queer and intersexual (LGBTQI) fiction, and aims to identify challenges that librarians consider important to address, on behalf of themselves and end users.

Design/methodology/approach

A web-based questionnaire comprising 35 closed and open questions, 22 of which were required, was sent via online channels in January 2022. By the survey closing date, 20 March 2022, 82 responses had been received. The study was intended to complement an earlier study targeting end users.

Findings

Both this study of librarians and the previous study of end users have painted a dismal image of online search services when it comes to searching for LGBTQI fiction. The need to consult different channels (e.g. social media, library catalogues and friends), the inability to search more specifically than for the broad LGBTQI category and suboptimal search interfaces were among the commonly reported issues. The results of these studies are used to inform the development of a dedicated Swedish LGBTQI fiction database with an online search interface.

Originality/value

The subject searching of fiction via online services is usually limited to genre with facets for time and place, while users are often seeking characteristics such as pacing, characterization, storyline, frame/setting, tone and language/style. LGBTQI fiction is even more challenging to search because indexing practices are not really being standardized or disseminated worldwide. This study helps address this important gap, in both research and practical applications.

Details

Journal of Documentation, vol. 79 no. 7
Type: Research Article
ISSN: 0022-0418

Keywords

Open Access
Article
Publication date: 30 October 2023

Koraljka Golub, Xu Tan, Ying-Hsang Liu and Jukka Tyrkkö

This exploratory study aims to help contribute to the understanding of online information search behaviour of PhD students from different humanities fields, with a focus on…

Abstract

Purpose

This exploratory study aims to help contribute to the understanding of online information search behaviour of PhD students from different humanities fields, with a focus on subject searching.

Design/methodology/approach

The methodology is based on a semi-structured interview within which the participants are asked to conduct both a controlled search task and a free search task. The sample comprises eight PhD students in several humanities disciplines at Linnaeus University, a medium-sized Swedish university from 2020.

Findings

Most humanities PhD students in the study have received training in information searching, but it has been too basic. Most rely on web search engines like Google and Google Scholar for publications' search, and university's discovery system for known-item searching. As these systems do not rely on controlled vocabularies, the participants often struggle with too many retrieved documents that are not relevant. Most only rarely or never use disciplinary bibliographic databases. The controlled search task has shown some benefits of using controlled vocabularies in the disciplinary databases, but incomplete synonym or concept coverage as well as user unfriendly search interface present hindrances.

Originality/value

The paper illuminates an often-forgotten but pervasive challenge of subject searching, especially for humanities researchers. It demonstrates difficulties and shows how most PhD students have missed finding an important resource in their research. It calls for the need to reconsider training in information searching and the need to make use of controlled vocabularies implemented in various search systems with usable search and browse user interfaces.

Open Access
Article
Publication date: 11 August 2023

Jacobus Gerhardus J. Nortje and Daniel Christoffel Myburgh

This paper aims to identify impediments, discuss impediments and make recommendations for the impediments during the execution of a search and seizure warrant for digital evidence…

Abstract

Purpose

This paper aims to identify impediments, discuss impediments and make recommendations for the impediments during the execution of a search and seizure warrant for digital evidence in South African criminal cases.

Design/methodology/approach

The discussion of this article, the second article of two, focuses on a literature review of international and local impediments identified in case law and published research literature and how it is approached in various jurisdictions.

Findings

This study found that impediments identified and addressed internationally during the execution of a search and seizure warrant for digital evidence are relevant to South African criminal cases and still need to be addressed during the execution of a search and seizure warrant for digital evidence in South African criminal cases.

Research limitations/implications

Although searches and seizures for digital evidence are relevant to civil, regulatory and criminal investigations, this study focuses on the search and seizure for digital evidence in criminal matters with an emphasis on the provisions of the Criminal Procedure Act 51 of 1977 and the Cybercrimes Act 19 of 2020.

Originality/value

The originality of this paper lies in the procedures followed during the physical search and seizure of digital information during the execution of search and seizure warrants for digital information in South Africa. If the South African Police Service follows the recommended procedures, it will contribute to the success of the South African Police Service, which would result in the improved quality of investigations and successful prosecution of crime in South Africa.

Details

Journal of Financial Crime, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1359-0790

Keywords

Open Access
Article
Publication date: 6 July 2023

Jacobus Gerhardus J. Nortje and Daniel Christoffel Myburgh

The purpose of this paper is to identify and discuss impediments in the compilation of an application for a search and seizure warrant for digital evidence and the structure of…

Abstract

Purpose

The purpose of this paper is to identify and discuss impediments in the compilation of an application for a search and seizure warrant for digital evidence and the structure of such a warrant in South African criminal cases.

Design/methodology/approach

This paper provides a brief overview of international and local impediments, followed by a detailed discussion of the implications of these impediments and how it is approached in various jurisdictions. The methodology of this paper consists of a literature review.

Findings

Addressing the impediments in the compilation of the application and the warrant will be beneficial for forensic investigators, the South African Police Service (SAPS) and the administration of justice in South Africa.

Research limitations/implications

Search and seizures for digital evidence form part of civil, regulatory and criminal search and seizures. This study focuses on the search and seizure of digital evidence in criminal matters pursuant to mainly the provisions of the Criminal Procedure Act 51 of 1977 and the Cybercrimes Act 19 of 2020.

Originality/value

The originality of this paper lies in the approach to the drafting of applications for search and seizure warrants for digital information in South Africa. The contribution of the study is that, by using this approach, the SAPS can address the impediments during the application and compilation of the warrants, which would enhance the quality of investigations and contribute to the successful investigation and prosecution of crime in South Africa.

Details

Journal of Financial Crime, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1359-0790

Keywords

Open Access
Article
Publication date: 14 October 2022

Koraljka Golub, Jenny Bergenmar and Siska Humlesjö

The purpose of this study is to investigate the needs of potential end-users of a database dedicated to Swedish lesbian, gay, bisexual, transgender, queer, and intersex (LGBTQI…

1100

Abstract

Purpose

The purpose of this study is to investigate the needs of potential end-users of a database dedicated to Swedish lesbian, gay, bisexual, transgender, queer, and intersex (LGBTQI) literature (e.g. prose, poetry, drama, graphic novels/comics, and illustrated books), in order to inform the development of a database, search interface functionalities, and an LGBTQI thesaurus for fiction.

Design/methodology/approach

A web questionnaire was distributed in autumn 2021 to potential end-users. The questions covered people's reasons for reading LGBTQI fiction, ways of finding LGBTQI fiction, experience of searching for LGBTQI fiction, usual search elements applied, latest search for LGBTQI fiction, desired subjects to search for, and ideal search functionalities.

Findings

The 101 completed questionnaires showed that most respondents found relevant literature through social media or friends and that most obtained copies of literature from a library. Regarding desirable search functionalities, most respondents would like to see suggestions for related terms to support broader search results (i.e. higher recall). Many also wanted search support that would enable retrieving more specific results based on narrower terms when too many results are retrieved (i.e. higher precision). Over half would also appreciate the option to browse by hierarchically arranged subjects.

Originality/value

This study is the first to show how readers of LGBTQI fiction in Sweden search for and obtain relevant literature. The authors have identified end-user needs that can inform the development of a new database and a thesaurus dedicated to LGBTQI fiction.

Details

Journal of Documentation, vol. 78 no. 7
Type: Research Article
ISSN: 0022-0418

Keywords

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