Description:
Multistage interconnection networks (MINs) have been widely adopted in communication networks especially in telecommunication and multiprocessor environments. This paper aims to evaluate the reliability performance of shuffle exchange network with an additional stage (SEN+), based on Monte Carlo method using computerized simulation. The evaluation is further improvised by deploying stratified sampling into the Monte Carlo method. SEN+ described in this paper is confined to multiprocessor environment based on identical switching elements used in interconnecting multiple processors. It is shown that Monte Carlo method is capable of providing reliability evaluation for SEN+ system.
Description:
An interconnection network system consists of layers of switching elements connected together in a predefined topology providing the connectivity between the set of processors and the set of memory modules. Performance analysis of a network system is important as it determines the usability and the efficiency of the network to provide services. A shuffle-exchange network (SEN), a specific type of Multistage Interconnection Network (MIN) that consists of 2x2 switching elements, has been widely considered as a practical interconnection system. This paper presents a network reliability model based on a minimum cut set method for SEN systems. A general equation for large-scale network reliability is derived subsequently to reduce the complexity of the reliability analysis for the interconnection network system. Read more: http://www.ijpe-online.com/p2-performance-analysis-of-a-multistage-interconnection-network-system-based-on-a-minimum-cut-set-method.html#ixzz34m0gTAiy
Description:
Multistage Interconnection Networks (MINs) are network systems providing fast and efficient communications at a reasonable cost. A gamma network is a specific class of MINs, which provides redundant paths in the system. In a gamma network, information from source nodes is transmitted through a specific set of routes to destination nodes. Reliability of an MIN is used as a measure of system’s ability to transform information from input to output devices. Due to the complexity of network configuration and availability of redundant paths, reliability bounds to estimate the exact reliability of a gamma network is proposed. A numerical example of an 8 × 8 gamma network is presented to demonstrate the accuracy of the reliability bounds. When the lower bound reliability provides sufficient assurance that the system will be operational at some specified time and closely approximates the exact reliability, then no further effort for obtaining the exact reliability expression is necessary.
Description:
In this paper, ways of improving planning, execution and management of projects using Numerical Design Structure Matrix (NDSM) method are presented to address interdependency of feedback and iteration, which is common in engineering projects management. The NDSM is an alternative approach to traditional project management tools such as Program Evaluation and Review Technique (PERT), Critical Path Method (CPM), and Gantt chart that can only allow the modelling of sequential and parallel processes in projects. As a case study, the model is tested on a set of tasks in a complex petroleum oil field development project, where task sensitivity and information variability attributes are derived. By applying the NDSM method, project duration is optimized and hence total cost of the project is reduced significantly.
Description:
In this paper, an implementation of lean manufacturing through learning curve modelling for labour forecast is discussed. First, various learning curve models are presented. Then the models are analyzed in terms of their advantages and limitations. As a case study, the learning curve modelling is presented with the data derived from a production company. With the application of the learning curve, labour need can be more accurately predicted and scheduled on time.
Description:
In this paper, an implementation of lean manufacturing through learning curve modelling for labour forecast is discussed. First, various learning curve models are presented. Then the models are analyzed in terms of their advantages and limitations. As a case study, the learning curve modelling is presented with the data derived from a production company. With the application of the learning curve, labour need can be more accurately predicted and scheduled on time.
Description:
Gamma Interconnection Network (GIN) is a type of Multistage Interconnection Network (MIN) that consists of layers of switching elements connected together in a predefined topology providing the connectivity between the set of processors and the set of memory modules. GIN is constructed by 1×3, 3×3 and 3×1 switching elements. In this paper, network reliability of four other different types of Gamma hybrid networks namely Monogamma Interconnection Network (MGIN), Reliable Gamma Interconnection Network (REGIN), Cyclic Gamma Interconnection Network (CGIN) and E×tra Stage Gamma Network (ESGN) are analyzed. The results from the proposed simulation method show that the ESGN, COIN and REGIN e×hibit high network reliability performance. This is subsequently followed by the MGIN, with a marginal network reliability improvement compared to the GIN. It is also shown that the reliability model used for simulation closely appro×imates the e×act network reliability of MGIN, COIN, and REGIN
Description:
This study focuses on cost and schedule issues of international development (ID) projects. Through empirical analysis we examine ID project cost and schedule performance and the main reasons for poor project outcome. We look at 100 projects that are sponsored by the Asian Development Bank and hosted by several Asian countries. The study identifies that most late projects experience cost underrun – an unusual cost and schedule variation relation in projects. Further we identify the root causes of project delay and cost underrun. Research findings will benefit ID project professionals, organizations and the ID project body of knowledge. The study can be extended to analyse other developing country projects sponsored by different donors.
Description:
In this paper, ways of improving planning, execution and management of complex engineering projects using design structure matrix (DSM) methods: path searching, powers of the adjacency matrix, and reachability matrix are presented. This is done by identifying loops or circuits in the project. The application of the DSM methods to minimize loops or circuits is discussed. As a case study, these methods are implemented to reduce design iterations or rework in a complex engineering project. By applying the DSM methods, the project duration can be minimized and hence the total cost of the project is reduced significantly.
Description:
A challenging aspect of managing the development of complex projects is the notion of design iteration or rework. Traditional project management tools such as program evaluation and review technique (PERT), critical path method (CPM), and Gantt chart allow the modelling of sequential and parallel processes in projects, but they fail to address interdependency of feedback and iteration. Design structure matrix (DSM) is a new approach to project management, used to represent, analyse dependencies among tasks and show the order in which tasks are performed. In this paper, a case of the petroleum oil field development project is demonstrated. The project duration of the petroleum oil field development project is reduced significantly by applying the DSM method.
Description:
This paper presents a case study on a reservoir simulation modeling of recycling gas condensate using Modified Black Oil formulation (MBO) to identify and recover the by-passed condensate in Al-Raja Field. Al-Raja field is a good candidate to utilize MBO formulation instead of fully compositional due to following reasons (1) Gas injection/recycling is able to maintain the reservoir pressure above or at the dew point pressure in Al-Raja Field. (2) by keeping reservoir pressure above dew point pressure, gas injection will prevent any Retrograde Liquid Deposit (RLD) occured in the reservoir. It was well accepted methodology that MBO can be used in lean to medium rich gas condensate reservoir under gas cycling above dew point. Al-Raja field is located in the Eastern part of the Marib-AlJawf Basin Republic of Yemen. The field has a moderate-size medium rich gas condensate reservoir with an average gas production rate of 750 MMscf/D from 18 wells. The lean gas is being re-injected back into the reservoir using line-drive pattern wells. Some make up gas from nearby fields was provided to replace fuel and shrinkage volumes. The high vertical relief of the field structure leads to significant temperature gradient that resulted in challenges to model the oil-gas ratio (Rv). The primary objective of the study is (1) to evaluate the current gas recycling performance at well and field level, (2) identify the location of current by-passed condensate (3) utilize the model to improve and optimize the liquid recovery through several options of optimum field developments (infill wells). To achieve the objectives, 3-D Static and Dynamic models with 4 components MBO definition were constructed. In this study, we will show how to generate PVT Modified Black Oil (MBO) properties such as solution gas-oil ratio (Rs), oil-gas ratio (Rv), oil formation volume factor (Bo), and gas formation factor (Bg), from PVT-EOS. Whitson and Torp procedures were selected to calculate MBO properties from PVT experimental data of gas condensate. The use of the MBO approach enabled us to perform faster field performance history matching compared with the compositional. This approach preserves less run time to conduct the Al-Raja prediction including infill drilling optimization. The condensate-gas ratio distribution achieved after the history match process guided us to locate the optimum infill well locations in by-passed area for the future development. Moderate condensate areas were located, and several wells have been drilled and proved to be successful. More infill wells were recommended to raise the field production and recover the remaining reserve.
Description:
In this paper, design structure matrix (DSM) methods are presented to manage design iteration or rework which is inherent in the design process. Three DSM methods: path searching, powers of the adjacency matrix, and reachability matrix methods are discussed. Their advantages and disadvantages with respect to the project scope are summarized. As a case study, DSM methods are implemented to reduce the design iteration or rework in a complex engineering project. The main advantage of the DSM methods over traditional project management tools such as CPM or Gantt chart is in compactness and ability to present an organized and efficient mapping among tasks that is clear and easy to read regardless of size.