Shiu Hong Choi and James Siu Lung Lee
Minimising makespan aims to achieve high utilisation of equipment and resources by getting all jobs out quickly. This is an important scheduling criterion, especially for…
Abstract
Minimising makespan aims to achieve high utilisation of equipment and resources by getting all jobs out quickly. This is an important scheduling criterion, especially for automated systems, because of the high investment cost. The problem, however, becomes complex when many parts and machines are involved. This is because different parts may require different numbers of operations, and there are many possible schedules. For small problems, a mathematical programming model for minimising makespan is formulated. For large problems, a sequencing algorithm based on decomposition and pairwise comparison is proposed. The idea of “total overlapping time” in the sequencing algorithm is introduced to determine the solution of each sub‐schedule. It maximises the number of jobs working at different machines at the same time, while satisfying the parts’ operation precedence and machine constraints. The differences between this method and the traditional graphical method are discussed. The sequencing algorithm significantly reduces the number of schedules for consideration and hence, the computational power required.
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Shiu Hong Choi and Feng Yu Yang
The research aims to develop a practicable method to solve relatively large job‐shop scheduling problems (JSSP) for production planning in real‐time.
Abstract
Purpose
The research aims to develop a practicable method to solve relatively large job‐shop scheduling problems (JSSP) for production planning in real‐time.
Design/methodology/approach
This paper analyses some search strategies based on machine‐order space, and proposes a filter search algorithm (FSA) to reduce computing time by improving the speed of finding a proper machine order. Numerical experiments are conducted to verify the FSA.
Findings
The experiments confirmed the superior performance of the FSA, making it possible to solve relatively large JSSPs in real‐time. The results showed that the leaf‐node number affects the solution quality. The performance can be improved by increasing the leaf‐node number. There is a significant decrease in the average quality deviation when the leaf‐node number increases; but the decreasing rate becomes minor when the leaf‐node number is relatively large. While triple filters may provide more leaf‐node numbers for the FSA, dual filters are considered enough for most practical scheduling problems. A method is proposed to determine appropriate leaf‐node numbers for practical production environments.
Research limitations/implications
A limitation is that the FSA's performance is affected by the choice of leaf‐node number. Although the relationships between the solution quality and the leaf‐node number for some problems have been worked out, it will be useful future research to deduce the relationships for other job‐shop instances of different sizes.
Originality/value
The FSA is a new approach, which is particularly useful for planning production schedules needed for efficient and responsive management of manufacturing systems to cope with increasing global competition and market changes.
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Shiu Hong Choi and James Siu Lung Lee
Minimizing penalty cost is one of the major objectives in FMS decision making when job‐due dates cannot be met. The study focuses on minimization of penalty cost when neither…
Abstract
Minimizing penalty cost is one of the major objectives in FMS decision making when job‐due dates cannot be met. The study focuses on minimization of penalty cost when neither increase in system capacity nor diversification of jobs to other plants or production lines is possible. A mathematical programming model combining both part type selection and scheduling decision making is proposed for small problems. For large problems, a simple control parameter is identified. Seven despatching rules are applied in conjunction with the control parameter and their differences in performance are reported. Not only proves that performance can be improved by a filtration process applied before despatching rules are applied, but also finds that there is no significant difference in performance between different despatching rules after the appropriate filtration process is applied. The effectiveness of the proposed control parameter is further illustrated by comparing the results with a continuous flow model.
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Shiu‐Hong Choi and James Siu‐Lung Lee
Job sequencing is an important stage in any hierarchical production control model, especially when a real‐time dispatching rule is not employed. The problems become complicated…
Abstract
Job sequencing is an important stage in any hierarchical production control model, especially when a real‐time dispatching rule is not employed. The problems become complicated when constraints, such as different parts requiring different operation processes at different machines and with different production priorities, are taken into consideration in the development of sequencing models. This paper first describes a mathematical programming model developed for small flexible manufacturing systems (FMS) makespan minimization sequencing problems. For large problems, a heuristic decomposition‐based algorithm is proposed. The algorithm is based on the proposed concept of track generation and track identification. Each part type may require a different number of operation processes at different machines. A numerical example is used to illustrate the use of the algorithm.
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Shiu Hong Choi and Feng Yu Yang
The disjunctive graph is a network representation of the job‐shop scheduling problem, while the longest path problem (LPP) is one of the most important subjects in this research…
Abstract
Purpose
The disjunctive graph is a network representation of the job‐shop scheduling problem, while the longest path problem (LPP) is one of the most important subjects in this research field. This paper aims to study the special topological structure of the disjunctive graph, and proposes a suite of quick value‐setting algorithms for solving the LPPs commonly encountered in job‐shop scheduling.
Design/methodology/approach
The topological structure of the disjunctive graph is analyzed, and some properties and propositions regarding LPPs are presented. Subsequently, algorithms are proposed for solving LPPs encountered in job‐shop scheduling.
Findings
The proposed algorithms significantly improve the efficiency of the shifting‐bottleneck procedure, making it practicable to realise real‐time scheduling and hence effective operations of modern manufacturing systems.
Originality/value
The paper demonstrates that it is possible to develop very efficient algorithms by imposing a special topological structure on the network.
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This paper, which originates in an English-as-a-foreign-language (EFL) classroom activity in Hong Kong, aims to explore English learners’ expressive and creative potential in…
Abstract
Purpose
This paper, which originates in an English-as-a-foreign-language (EFL) classroom activity in Hong Kong, aims to explore English learners’ expressive and creative potential in writing by studying their work in the literary narrative genre.
Design/methodology/approach
A group of upper secondary students (15-16 years of age) with limited English resources and competence was enlisted to remake a folktale with visual and written prompts.
Findings
The writing samples demonstrate that these low-level EFL writers are able to refashion the narrative elements, and to communicate meanings for their own purposes. They exhibit logicality and problem-solving skills in their attempts to challenge and transform idea and to include themes of interest to them. There is also evidence of creative play with language in their use of dialogues and figures of speech.
Research limitations/implications
These writing outcomes suggest the need to re-vision English language arts practices in increasingly diverse education systems. Genre-based instruction, with its emphasis on “writing to mean” as a social activity supported by learning to use language, could lead to widening EFL learners’ access to genre knowledge and to greater life chances.
Practical implications
A linguistics-based pedagogy scaffolding less able EFL writers while they learn to build effective narratives is identified as a way forward.
Originality/value
Although the idea of using narratives to engage EFL learners in writing is not entirely new, this paper contributes to the field by responding to low-level learners’ writing that goes beyond linguistic “correctness”, and developing strategies for supporting creativity and language play.
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Natrawan Amornpornwiwat and Supara Kapasuwan
This study focuses on tourists’ perceptions of a capsule hotel, a budget form of accommodation with a unique appearance and the small size of a sleeping pod. The data were…
Abstract
This study focuses on tourists’ perceptions of a capsule hotel, a budget form of accommodation with a unique appearance and the small size of a sleeping pod. The data were obtained in Bangkok from 402 foreign travellers from over 30 countries. The results indicate that room size, sleep ambient control system and in-room television were the three main attributes that were positively correlated with decisions to stay in such hotels. Tourists with previous experience of staying in capsule hotels had more positive perceptions regarding room size and indicated higher intentions to stay than those without such experience. The researchers also found that budgetary considerations negatively moderated the relationship between room size and intention-to-stay. Additionally, the relationship between intention-to-stay and three other hotel attributes, including room size, the service scape and perceived security, was weaker for female travellers than for male travellers. Lastly, risk avoidance also positively moderated the relationship between intention-to-stay and location and security.
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Sladjana Cabrilo, Rosanna Leung, Fu-Sheng Tsai and Sven Dahms
This study explores how customers' individual characteristics and perceptions affect acceptance of service robots as a hotel workforce. The Interactive Technology Acceptance Model…
Abstract
Purpose
This study explores how customers' individual characteristics and perceptions affect acceptance of service robots as a hotel workforce. The Interactive Technology Acceptance Model (iTAM) has inspired us to investigate effects of customers' technological self-efficacy, perceived interactivity, sense of utility, and enjoyment-level of acceptance related to hotel-service robots as staff.
Design/methodology/approach
Data were collected from 224 customers via an online questionnaire conducted in the period April–June 2022 by convenience sampling, and then analyzed by using partial least squares – structural equation modeling (PLS-SEM).
Findings
The findings show that customers' technological self-efficacy and perceived interactivity with service robots enhances perceived usefulness and perceived enjoyment, serving as functional and emotional value components of service robots. They also demonstrate that robot's interactivity outweighs other robot's value components, such as perceived usefulness and perceived enjoyment for acceptance of service robots as employees in hotels.
Originality/value
While empirically validating the iTAM, this study emphasizes service robot interactivity as the most important aspect for customers' acceptance, and it adds a new perspective regarding the underexplored role of the customer-robot interface. Combining specific dimensions from different technology acceptance models (functional/socio-emotional/relational; utilitarian/hedonic) the study contributes to the service robot literature currently missing a more holistic understanding of consumers' experience and adoption drivers, and it provides managerial guidance on how to successfully implement service robots in hotel environments.
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Leila Alinaghian, Jilin Qiu and Kamran Razmdoost
The purpose of this paper is to systematically review and assess the current status of research on supply chain sustainability from a network structural perspective and provide an…
Abstract
Purpose
The purpose of this paper is to systematically review and assess the current status of research on supply chain sustainability from a network structural perspective and provide an organising framework for future scholarship in this area.
Design/methodology/approach
By adopting an evidence-based approach, this study conducts a systematic review of 73 articles from 18 peer-reviewed journals published between 2000 and 2020.
Findings
Adopting a social network analysis approach, the review identifies specific node-level (i.e. degree centrality, closeness centrality and betweenness centrality) and network-level (i.e. network density, network sub-groups and network diversity) structural properties that play a role in supply chain sustainability. The results reveal that structural properties determine the extent of perception of sustainability risks, the diffusion of sustainability targets, introduction of sustainable innovations, development of sustainability capabilities, adoption of sustainability initiatives and the monitoring of sustainability performance throughout the supply chain.
Originality/value
By distinguishing between supply network and sustainable supply network types, this study extends the existing understandings of the role of network connectivity patterns in supply chain sustainability through synthesising and evaluating the extant literature. This study further clarifies the role of these network structural properties in supply chain sustainability by describing their impact on a set of sustainable supply chain management practices through which firms achieve sustainability goals across their supply chains.