But-For analysis is a popular technique for apportioning the responsibility for project delays among various parties. In the literature, Modified But-For (MBF) methods utilized Venn representations ...and set theorem to avoid conflicting results and identify concurrent delays. Moreover, the MBF was extended further to analyse cases involving schedule delays and accelerations. However, due to its single-window implementation, the MBF analysis is not sensitive to event chronology and thus can produce wrong results. This article thus proposes a multiple-window MBF analysis to account for critical path fluctuations and consider the detailed chronology of progress events, which are key requirements of the professional delay analysis guidelines of AACEI and ASCE. The proposed method is comprehensive enough to analyse concurrent delay and acceleration events under multiple baseline updates. After introducing the proposed method, a case study is used to demonstrate its superiority and practical application.
Railway operations are organized according to a complex interplay of resources and according to a rigid time separation of train runs over infrastructure elements. The system dynamics are complex, ...and span in time and space. We use in this work the concepts of macroscopic fundamental diagrams, or more in general the analysis in a density-flow-speed diagram, to analyse and describe realized railway operations.
Specifically, we review the state of the art in aggregated models of railway performance. We illustrate a possible application by means of a test case. We consider realized railway operations, aggregated on a railway line with heterogeneous traffic, as measured in a set of stations. We use a density-flow-speed diagram to represent the recorded operations, similar to the concepts of macroscopic fundamental diagram or network fundamental diagram. In this sense, it is a first try to estimate a macroscopic relationship, from realized data based on heterogeneous railway services with different stopping patterns.
The analyses show the challenges of aggregate operations for different railway stretches, from realized data. We report what is the influence of delays, represented in those diagrams by a shift of the operating point. Future promising directions of research are concluded from the analysis.
•We review aggregated models of railway performance.•We analyse realized railway operations with heterogeneous traffic.•A density-flow-speed diagram represents the recorded operations.•Macroscopic relations are identified by means of Principal Component Analysis.•A roadmap of applications is identified.
-Now adays Very Large-Scale Integration (VLSI) circuits have good or great demand. Because CMOS circuit design having less power consumption. Transistors on the chip is doubled every two years, ...according to Moore’s law. So, it means transistor size is decreasing. This leads to increase the chip density and decrease the device size. The write and read depending on the bitline and bitline bar discharging and charging. When design the memory in below 16 nm uses Fin Field effect Transistor (FinFET) technology instead of CMOS (Complementary metal oxide semiconductor field effect transistor). Because to avoid short channel effect. Comparing leakage power, dynamic power and static power at 90 nm technology and write delay, read delay at both 90 nm and 45 nm technology in nine transistors (9 t), eight transistor (8 t) and six transistor (6 t) sram cell.
Nowadays, one of the major sources of issues in the construction sector in the Middle East and North Africa (MENA) region is the Extension of time (EOT) claims, which is so hard to resolve. Authors ...and practitioners have started trials in numerous academic studies to show how to properly deploy Delay Analysis Methods (or "DAMs") and to give practitioners executive guidelines to support them with proper analyses and claim resolution. The awareness of the use of these methods is essential to realize their restrictions and capacity to fit in with various project circumstances and to select appropriate delay analysis methods. The main objective of this research is to provide a guide for the selection of appropriate DAM by defining a list of important criteria that have the most preference in choosing the effective method. These criteria will be rated by collecting feedback from experts in the MENA region through questionnaires. The survey was conducted in the United Arab Emirates (UAE) for the abundance of multinational firms working on mega construction projects with multicultural backgrounds and diversity of expertise in addition to the availability of carrying out interviews when needed and the widespread adoption of standard international construction contracts. Then, the possibility of ranking is calculated by using the Relative Importance Index (RII). This ranking will be considered as an important tool for the proper selection of convenient delay analysis methods. Ultimately this paper will facilitate the selection of appropriate DAM by Delay analyst through investigating project circumstances by mapping it with current ranked criteria.
In this paper, a novel cognitive multiple-access strategy in the presence of a cooperating relay is proposed. Exploiting an important phenomenon in wireless networks, source burstiness, the cognitive ...relay utilizes the periods of silence of the terminals to enable cooperation. Therefore, no extra channel resources are allocated for cooperation and the system encounters no bandwidth losses. Two protocols are developed to implement the proposed multiple-access strategy. The maximum stable throughput region and the delay performance of the proposed protocols are characterized. The results reveal that the proposed protocols provide significant performance gains over conventional relaying strategies such as selection and incremental relaying, specially at high spectral efficiency regimes. The rationale is that the lossless bandwidth property of the proposed protocols results in a graceful degradation in the maximum stable throughput with increasing the required rate of communication. On the other hand, conventional relaying strategies suffer from catastrophic performance degradation because of their inherent bandwidth inefficiency that results from allocating specific channel resources for cooperation at the relay. The analysis reveals that the throughput region of the proposed strategy is a subset of its maximum stable throughput region, which is different from random access, where both regions are conjectured to be identical.
This paper presents a high-sensitivity high-speed dynamic voltage comparator, which is a key component for low power CMOS mixed signal applications. The proposed dynamic comparator employs ten ...transistors with only one cross-coupled latch to reduce the circuit complexity. The parallel clocked input switches reduce parasitic resistance in the latch ground path that results in a significant decrease in latch delay time. In addition, a symmetric, three stacked transistor, single stage architecture reduces the process variation effects, increases input sensitivity and provides more head room for low power-supply applications. The proposed design is implemented in 90 nm CMOS with 1.2 V power supply and 0.6 V reference voltage, and it provides 30 μV resolution, 105.6 μW power consumption at 2 GHz clock frequency.
•The economical impact of non-ATFM delays is expected to grow in the near future.•We propose a method for characterising en-route non-ATFM delays.•We define a metric to measure temporal and spatial ...airborne resilience.
The analysis of the causes behind the appearance and propagation of delays is one of the major topics inside Air Transport Management research. Existing research focuses by and large on Air Traffic Flow Management regulations and reactionary delays; less attention has been devoted to the study of the mechanisms governing the generation and absorption of delays while airborne, in spite of their important economical and environmental consequences. Here we present a methodology to detect delay-generating events, based on the comparison of planned and real trajectories; these events are then used to characterise several aspects of the dynamics of the system, e.g. its resilience. We apply this methodology to a historical data set of flights crossing the European airspace during 2011, and observe an overall resilient system, able to absorb as much delays as it generates; yet resilience is not constant, but strongly depends on the phase of the flight, and shows high spatial and temporal heterogeneities. We anticipate the proposed methodology to open new doors for the development of a better systemic performance, by enabling the characterisation and understanding of this fundamental type of delay.
Statistical analysis method has emerged as a general approach to detect relation alarms in the process industries. However, the delay between related alarms is the main cause leading to wrong ...analysis results from traditional approaches to detect correlated alarms. This paper proposed a novel detection of correlated alarms based on block matching similarities with delay (BMS-d). First, blocking alarm data sequence method is to transform alarm data into time node sequences, which is able to reduce the calculation burden of the correlation analysis. Second, a novel maximal block correlation coefficient method is presented to estimate the correlation delay between alarms. Third, a novel method is proposed to detect correlated alarms based on the block matching similarities and related alarm delay information. A numerical case and TE process are employed to demonstrate the effectiveness and efficiency of the proposed method.
•This paper proposed A Novel Detection of Correlated based on improved BMS.•The proposed BMS-d method aims at reducing the calculation burden of the correlation analysis.•The proposed BMS-d method can estimate transfer time delay between alarm variables.
•Schedule delay assessment: a traditional problem in complex and large projects.•Evaluation of schedule delays and allocation to responsible parties.•Rational ways to prevent claims and provide ...project management control.•Improved method to assess schedule delays and integrate current legacy software.•“Float bank” method to support delay evaluation and float management.
The analysis of schedule delays is a traditional problem in almost any project of some dimension and complexity. Assessing schedule delays and allocating them to responsible parties and activities is a sensitive problem in project management. In client-supplier, i.e. owner-contractor relations, the schedule delays represent a very important issue, often escalating into claims and undermining the commercial outcome of the whole project, involving lengthy negotiations and juridical cases, tracing to responsibilities and financial compensations. The present work tackles the problem of schedule delays, linking to literature already present on the subject and extending some solutions already published. In particular we introduce the concept of “float bank”, as a mean to assigning and sharing delay responsibilities between the project actors, i.e. owner, contractor and force majeure. We introduce the implementation of an algorithmic method and application of a complete case study which can be of interest to practitioners and stakeholders in the field of project management, potentially to integrate with commercial or in-house software and assist current project control, claim cases and newly so-called forensic project management.
This paper presents a robust predictive control scheme with a graphic-based delay boundary analysis to mitigate the electric vehicle (EV) drivetrain oscillating issues, subject to the multi-channel ...compounding-construction loop delays. The application of Controller Area Network (CAN) in autonomous electric vehicles (AEVs) inevitably induces multi-channel compounding-construction loop delays into the control loop. The in-deep analyzing and understanding of the network-induced loop delays is critical for the electrified powertrain and its motion control. This study aims to guarantee, explicitly, the motion stability of AEV drivetrains as safe-critical and hard real-time applications. Firstly, a graphic-based constructional representation approach is presented for modeling of the compounding-construction loop delays. To resolve the upper bound of the compounding-construction loop delays further, a mathematic expression of delay boundary-envelopment analysis is derived. Secondly, based on the reasonable upper bound, Taylor series expansion is applied to make the system model with nonlinear uncertainties caused by the network-induced loop delays represent in the form of the convex polytope. Then, with the convex polytope of the drivetrain system model, a robust model predictive control (RMPC) approach is developed to enhance the system robustness against the unexpected network-induced delays. To attenuate the online calculation burden, a scheme combining off-line design and on-line synthesis is provided. Finally, the satisfactory motion control performance in both the co-simulations (Matlab&Carsim) and bench experimental tests can strongly verify the effectiveness of the proposed approaches.
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