Search results

The purpose of this paper is to develop an attitude control strategy for the reusable boosted vehicle with large angle of attack, and to remove the cross coupling among roll, pitch and yaw channels.

The coordinated gain scheduling control strategy consists mainly of two parts. First, initially ignoring dynamic coupling, single channel gain scheduling controller is designed based on linearized models, respectively. Second, with respect to main channel gain scheduling controller, coordinated scheduling controller is used to generate intentionally cross coupling to partly cancel inter‐channel cross coupling of reusable boosted vehicle.

A coordinated gain scheduling control strategy is presented, and no such analytical solution can be found for the reusable boosted vehicle.

The design idea of coordinated gain scheduling strategy is straightforward in physical concepts and has great value for engineering applications.

Coordinated gain scheduling control strategy is novel in that single channel gain scheduling design does not involve small perturbation linearization and coordinated channel is scheduled.

The traditional practice for maintenance, quality control and production scheduling is to plan independently irrespective of an interrelationship exist between them. The purpose of this paper is to develop an approach for integrating maintenance, quality control and production scheduling. The objective is to investigate the benefits of the integrated effect in terms of the expected total cost of system operation of the three functions.

The proposed approach is based on the conditional reliability of the components. Cost model for integrating selective maintenance, quality control using sampling-based procedure and production scheduling is developed using the conditional reliability. An integrated approach is such that, first an optimal schedule for the batches to be processed is obtained independently while the maintenance and quality control decisions are optimized considering the optimal schedule on the machine. The expected total cost of conventional approach, i.e. “No integration” is calculated to compare the effectiveness of integrated approach.

The integrated approach have shown a higher cost saving as compared to the independent planning approach. The approach is practical to implement as the results are obtained in a reasonable computational time.

The approach presented in this paper is generic and can be applied at planned as well as unplanned opportunities. The proposed integrated approach is dynamic in nature, as during maintenance opportunities, it is possible to optimize the decision on maintenance, quality control and production scheduling considering the current age of components and production requirement.

The originality of the paper is in the approach for integration of the three elements of shop floor operations that are usually treated separately and rarely touched upon by researchers in the literature.

IN our series of papers on Production Control in Aircraft Engineering, we have so far covered the following subjects: (1) Preproduction Planning (Dec. 1942), (2) The Production Plan (July 1944), (3) Shop‐loading (Aug. 1943), (4) Manufacturing Order Control (Jan. 1944), (5) A System of Works Control (September 1943). The British Standards Institution in their booklet 1100, Part I, Principles of Production Control, give 6 subjects as covering the entire field, (1) Scheduling, (2) Machine and Labour Utilization, (3) Stock Control, (4) Manufacturing Order Control, (5) Progressing, and (6) The Production Plan. It will therefore be seen that No. 1, Scheduling; No. 3, Stock Control; No. 5, Progressing, have not been covered. (Note: At this stage, we can assume that No. 2, Machine and Labour Utilization, was sufficiently dealt with in the Shop‐loading paper.)

The purpose of this paper is to examine the effect of work schedules on work‐family conflict and synergy using the job demands‐resources (JD‐R) and conservation of resources models. The impact of resources including supervisor support, work schedule control and satisfaction, as well as the moderating effects of work schedules on conflict (synergy) and domain satisfaction are examined.

This quantitative study examined responses from organizationally‐employed respondents (n=2,810) from the 2002 National Study of the Changing Workforce using MANOVA and multiple regressions.

Work schedules were significantly related to work‐interfering with family (WIF) and work‐family synergy (W‐FS) but not for family interfering with work (FIW). Perceived supervisory support was significantly related to employee work schedule control and work schedule satisfaction. Perceived control of work schedule and work schedule satisfaction were significantly related to work‐family conflict and synergy. Work schedules moderated the relationship between work‐family conflict (synergy) and domain satisfaction.

Although based on a national probability sample, this study may suffer from common method variance since all measures were from the same self‐report questionnaire.

The results do suggest that solutions like increased schedule flexibility for all workers may not be efficacious in reducing work‐family conflict or increasing work‐family synergy. Employee control over work schedule, employee satisfaction with work schedule, and supervisor support need to be considered as well.

This study examined the impact of work schedules on work‐family conflict and synergy. It is noteworthy since very little research has been conducted on work schedules and synergy. The results also broaden evidence for the JD‐R and conservation of resources models.

Learner control is a widely touted and popular element of e-learning, both in the educational and organizational training domains. In this chapter, we explore the concept of learner control, highlighting its multidimensional and psychological nature. We examine the theoretical basis for the effects of learner control on learning and engagement. Next, we provide the reader with empirically based recommendations for designing learner-controlled training. We conclude by discussing how learner control research may be adapted to accommodate a variety of instructional methods, such as textbooks, mobile learning, and Massive Open Online Courses (MOOCs).

There has been much discussion on the merits of different production control philosophies, particularly MRPII, OPT and JIT. A consensus is emerging that these philosophies are not mutually exclusive, and some companies are beginning to mix and match different approaches to meet their particular needs. The design of hybrid production control systems requires the establishment of a theory of production control that embraces, but is independent of, the well‐defined philosophies of MRPII, OPT and JIT. Without such an understanding of production control there is no framework within which to build hybrid production control systems. Five universal principles of production control are set out, and it is shown how these principles can be used to construct the Integrated Production Control (IPC) Model. This model provides the conceptual framework necessary for the design of hybrid production control systems. The relationships of MRPII, OPT, and kanban, the classical JIT scheduling system, are explored, and areas of strength and weakness identified.

This paper aims at improving progress tracking and control of repetitive projects by developing a novel framework that automates the documentation of as-built information directly into the project schedule and also introduces enhanced linear scheduling formulation to support project control decisions.

The proposed framework uses e-mail technology to facilitate detailed tracking of daily as-built events of all parties through bidirectional communication between site and head office. It also provides a new formulation for more accurate critical path and linear scheduling computation to accurately update the project's time and cost during construction.

Using a case study of a road project, the paper proves that the proposed framework reduces as-built documentation effort and its schedule updates are more responsive to all as-built events than traditional scheduling techniques.

The proposed method applies to linear projects (e.g. highways) and can be extended to other repetitive projects such as high-rise buildings. It can also be extended to include voice features and procedures for forensic schedule analysis.

The developed methodology presents a low-cost approach to document timely progress information for decision makers of massive linear projects (often associated with infrastructure) to have better control over the execution of projects, save documentation time and cost, and avoid disputes and problems.

This research contributes in improving construction productivity by collecting timely as-built information using affordable communication technologies. It also presents novel advancements to the existing scheduling and control techniques to suit linear projects, which are most challenging.

The purpose of this paper is to present a new method for project tracking and control of integrated offsite and onsite activities in modular construction considering practical characteristics associated with this type of construction.

The design embraces building information modelling and integrates last planner system (LPS), linear scheduling method (LSM) and critical chain project management (CCPM) to develop tracking and control procedures for modular construction projects. The developed method accounts for constraints of resources continuity and uncertainties associated with activity duration. Features of proposed method are illustrated in a case example for tracking and control of modular projects.

Comparison between developed schedule and Monte Carlo simulation showed that baseline duration generated from simulation exceeds that produced by developed method by 12% and 10% for schedules with 50% and 90% confidence level, respectively. These percentages decrease based on interventions of members of project team in the LPS sessions. The case example results indicate that project is delayed 5% and experienced cost overrun of 2.5%.

Developed method integrated LPS, LSM and CCPM while using metrics for reliability assessment of linear schedules, namely, critical percent plan complete (PPC_cr) and buffer index (BI). PPC_cr and BI measure percentage of plan completion for critical activities and buffer consumption, respectively. The developed method provides a systematic procedure for forecasting look-ahead schedules using forecasting correction factor Δ_t and a newly developed tracking and control procedure that uses PPC_cr and BI. Quantitative cost analysis is also provided to forecast and monitor project costs to prove the robustness of proposed framework.

The purpose of this paper is to propose an integrated earned value management (EVM) approach to control quality, cost, schedule and risk of projects.

This study represents a new EVM framework by considering a quality control index. Particularly, some control indices and cumulative buffers are defined by two proposed, methods, namely the linear- and Taguchi-based methods. These methods are implemented in three different projects in different industries.

According to the results, integration of the quality index creates a better control situation by providing more accurate information. Hence, project managers could comprehensively monitor the status of important factors to make more precise decisions while maintaining the simplicity of their analysis.

From the methodological and theoretical features, this paper offers new visions because, to the best of authors’ knowledge, no comparable study has been conducted before.

The implementation and control processes of project planning and scheduling involve a wide range of methods and tools. Despite the development and modification and integration of the project management theory with newer scheduling approaches in particular, practitioners’ views on the efficiency and effectiveness of these methods and tools differ. This situation can be attributed in part to a lack of understanding of the most appropriate basis for implementing these methods and tools. This study, therefore, aims to overcome this deficiency by conceptualizing and adopting a taxonomy of planning and scheduling methods.

The study is based on a review and discourse analysis of the literature covering a large number of theoretical and empirical studies. The underlying theories of various planning and scheduling methods were analyzed with respect to the taxonomy criteria adopted in the study.

Using the taxonomy, the key characteristics of planning and scheduling methods considered in this study were identified and interpreted. These included concepts and theories; key features; suitability and usability; and benefits and limitations. Overall, the findings suggest that project managers should consider taxonomy as a support tool for selecting and prioritizing the most appropriate method or combination of methods for managing their projects. Recommendations include the need for more advanced or multi-dimensional taxonomies to cope with the diversity of project type and size.

The results of the study allow project managers to improve their current practices by utilizing taxonomy when considering the implementation of planning and scheduling methods. Moreover, taxonomy can be considered as a tool to promote learning on the part of those less experienced in planning and scheduling. Taxonomy can be considered as an initial platform for further research in this area.