43 research outputs found
Performance of the Construction Manager at Risk (CMAR) Delivery Method Applied to Pipeline Construction Projects
No full textabstract: Much of the water and wastewater lines in the United States are nearing the end of their useful life. A significant reinvestment is needed in the upcoming decades to replace or rehabilitate the water and wastewater infrastructure. Currently, the traditional method for delivering water and wastewater pipeline engineering and construction projects is design-bid-build (DBB). The traditional DBB delivery system is a sequential low-integration process and can lead to inefficiencies and adverse relationships between stakeholders. Alternative project delivery methods (APDM) such as Construction Manager at Risk (CMAR) have been introduced to increase stakeholder integration and ultimately enhance project performance. CMAR project performance impacts have been studied in the horizontal and vertical construction industries. However, the performance of CMAR projects in the pipeline engineering and construction industry has not been quantitatively studied.
The dissertation fills this gap in knowledge by performing the first quantitative analysis of CMAR performance on pipeline engineering and construction projects. This study’s two research objectives are:
(1) Develop a CMAR baseline of commonly measured project performance metrics
(2) Statistically compare the cost and schedule performance of CMAR to that of the traditional DBB delivery method
A thorough literature review led to the development of a data collection survey used in conjunction with structured interviews to gather qualitative and quantitative performance data from 66 completed water and wastewater pipeline projects. Performance data analysis was conducted to provide performance benchmarks for CMAR projects and to compare the performance of CMAR and DBB.
This study provides the first CMAR performance benchmark for pipeline engineering and construction projects. The results span across seven metrics in four performance areas (cost, schedule, project change, and communication). Pipeline projects delivered using CMAR have a median cost and schedule growth of -5% and 5.10%, respectively. These results are significantly improved from DBB baseline performance shown in other industries. To verify this, a statistical analysis was done to compare the cost and schedule performance of CMAR to similar DBB pipeline projects. The results show that CMAR pipeline projects are being delivered with 6.5% less cost growth and with 12.5% less schedule growth than similar DBB projects, providing owners with increased certainty when delivering their pipeline projects.Dissertation/ThesisDoctoral Dissertation Civil Engineering 201
A 10 Mbit/s Upstream Cable Modem with Automatic EqualizationPatrick Schaumont Radim Cmar Serge Vernalde Marc Engels
No full textA fully digital QAM16 burst receiver ASIC is presented. The BO4 receiver demodulates at 10 Mbit/s and uses an advanced signal processing architecture that performs perburst automatic equalization. It is a critical building block in a broadband access system for HFC networks. The chip was designed using a C++ based flow and is implemented as a 80 Kgate 0.7u CMOS standard cell design. 1 Introduction The widespread use of Internet is opening a pathway to emerging multimedia consumer networks and applications. These require a broadband data communications link to be established in the access network that connects the consumer to a core service network. The hybrid fiber-coax (HFC) access network that is currently in use for cable TV, is considered as an attractive candidate [4]. We have developed a chip that is embedded in an HFC head-end and that demodulates data transmitted from the consumer set-top. This chip is a fully digital burst receiver, characterized as shown in table 1. The chip..
DSL and Autotuning Tools for Code Optimisation on HPC Inspired by Navigation Use Case
No full textWhen targeting high performance computing (HPC) platforms, improving the performance and scalability of code is often a tedious and time consuming task. The code has to be executed and even compiled many times under different conditions in order to observe its behaviour on the target
hardware. These experiments are performed with the goal of estimating an optimal set of the run-time environment parameters to achieve optimal performance and energy efficiency. This optimization task is best performed automatically, but due to the heterogeneous nature of the source codes and the
HPC platform, fully automation is often hard to implement. The domain specific language (DSL) and toolflow approach proposed in the ANTAREX project ( www.antarex-project.eu ) can provide the mechanisms needed for addressing properly the problems previously described. The DSL being developed
is based on the LARA DSL [1] and allows to specify strategies for code instrumentation and code transformations, including the required code adaptation for dynamic autotuning [2]. By using instrumentation strategies, the measurements can be integrated seamlessly into the development process, e.g., as a standalone stage in the continuous integration process. The ANTAREX project plans to demonstrate the usage of the LARA DSL and the autotuning approach on two
use cases in cooperation with commercial partners, HPC Accelerated Drug Discovery System (Dompe), and the Self-adaptive Navigation System (Sygic). The poster is focused on the presentation of the DSL and autotuning tools for the self-adaptive navigation system use case, which basic idea is to
combine server-side and client-side data knowledge and their routing capabilities to provide the most efficient navigation system in the context of smart cities. In such a use case, we assume a significantly large portion of drivers participating in the system. The efficiency is essential given that the routing
system needs to serve many requests requiring potentially huge computation power. Then still, even without limits to be reached, it is desirable to optimize the execution of such a system with respect to the energy efficiency.
The probabilistic Time-Dependent Travel Time Computation algorithm [3] has been selected for the demonstration of DSL and autotuning tools usage in the Self-adaptive Navigation System. The input for the algorithm is a departure time and a selected route composed as a line of road segments. A Monte Carlo simulation (MCS) is used for the computation of the probability distribution of travel time for the selected route. The simulation randomly selects probabilistic speed profiles on
road segments and computes travel time at the end of the route. Many MCS iterations are needed to obtain enough travel times for the construction of the probability distribution of travel time. The number of simulation iterations greatly affects the precision of the result
One day FCD data of Prague
No full text<p>One day floating card data (FCD) of Prague.<br>
One FCD data point represents one datum sensed from vehicle containing a GPS position and the speed of a vehicle</p>
Training sequences for road speed prediction on a selection of roads in Prague
No full text<p>Training sequences for 1 hour road speed prediction training on a selection of roads in Prague retrieved from IT4I traffic simulator.<br>First 4 columns define road identifiers, for which a timeline of speed information is provided in the next columns.<br>5th column marks the time of a day (in the range 0 to 24), which is associated with a sample as a reference time stamp.<br>Next 16 columns represent 4 timeline sequences for the 4 concerned roads over past 1 hour (vx@ represents 15min back,vx@@ 30min back, etc).<br>Last 4 columns represent timeline sequence of an output road referring to the 1<span> </span>hour future (vx+ mark represents 15min forward, vx++ 30min forward, etc.)</p>
<p>Speed value -1 means the information for a particular time instance for a particular road is missing.</p>
Road speed profiles of Prague 2022
No full text<p>Road speed profile defines average speeds across 24 hour in 15min granularity, i.e. 96 speed values per day per road.<br>The file defines the road speed profile for about ~8000 major roads of Prague.<br>The road speed profiles have been derived from FCD data collection on the date of 19.2.2022.<br>Each road is denoted by a unique road identifier. For a geo position please refer to road network definition (see roadnetwork files) </p>
Project Delivery Method Performance Evaluation for Water and Wastewater Capital Projects
No full textabstract: The water and wastewater industry in the United States is in dire need of renovation due to dwindling infrastructure and requires substantial reinvestment. Design-bid-build (DBB) is the traditional method of project delivery most widely applied in this industry. However, alternative project delivery methods (APDM) are on the rise and touting the benefits of reduced project schedule and cost. The main purpose of this study is to conduct a qualitative and quantitative performance evaluation to assess the current impact of APDM in the water and wastewater industry. A national survey was conducted targeting completed water and wastewater treatment plant projects. Responses were obtained from 75 utilities and constructors that either completed their projects using DBB, construction manager at risk (CMAR), or design-build (DB). Data analysis revealed that CMAR and DB statistically outperformed DBB in terms of project speed and intensity. Performance metrics such as cost growth, schedule growth, unit cost, factors influencing project delivery method selection, scope changes, warranty and latent defects, and several others are also evaluated. The main contribution of this study was that it was able to show that for the same project cost, water and wastewater treatment plants could be delivered under a faster schedule and with higher quality through the utilization of APDM.Dissertation/ThesisMasters Thesis Construction Management 201
Toward a Small Donor Democracy: The Past and Future of Incentive Programs for Small Political Contributions
No full textThe author begins by stating the importance of monetary contribution to a campaign and points out that most of the money for campaigns comes in the form of large donations. It then goes the introduction of campaign contributions as federal tax credits and its effects until the repeal of the tax credit by Congress. The articles then discusses state implementation of tax credits for political contribution, and compares the effects of different state programs. The article then introduces the principle that contribution incentive programs can be part of a strategy for campaign finance reform and gives several ideas how this can be done. He states that it would encourage maximum participation from small donors, should combine with additional reforms to make small contributions a central part of funding, and outlines steps to achieve that goal. The article then states benefits of a new federal tax credit, including more contributions from small donors and healthier democracy with modest costs. The article concluded by restating that political contribution incentive programs are a promising approach to increasing the voice of small donors and states several issues with this and qualifications to its success
