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1.
Comparisons of industry sectors in advanced economies since the 1960s show that the construction sector has lagged in productivity growth rates, especially in the United States. Although the US and Canadian economies are highly integrated, Canada’s experience differs in key ways. Analysis of these differences offers insight into fundamental construction productivity drivers. Three levels of analyses of construction productivity in the US are provided in this study. The first analysis compared international levels of labour productivity growth. The second compared construction productivity between the US and Canada, and the third analysed cost estimating data from RS Means estimating manuals to measure the changes in labour and partial factor productivity in the US from 1995 to 2009. Statistical significance testing indicates that labour productivity remained nearly constant in the building sub-sector and that partial factor productivity has improved at an annual compound rate of 0.66%. This supports previous findings that US construction has stagnated but is still improving in Canada, with wage differentials and training systems as potential drivers of this difference. While growth rates of productivity seem to decline with higher absolute levels of productivity, there is no evidence that high absolute productivity levels preclude significant growth.  相似文献   
2.
Recent studies show the construction industry in the USA is facing a long term labour shortage. Multiskilling has been suggested as a strategy to address this issue by utilizing existing workers more efficiently. Multiskilling decreases the number of workers hired for a project and can improve productivity. Additional benefits include higher income and increased employability of the workforce. To take full advantage of these benefits, the workforce strategy and the planning and scheduling processes of a construction project must be adapted to use multiskilling effectively and efficiently. The multiskilled workforce should be scheduled and organized to maximize the duration of employment for workers, reduce the overall labour requirements and cover the skills combinations required by the project. This research synthesizes and formalizes the methods that successful construction companies are currently applying to implement a multiskilled workforce. A methodology for implementing multiskilling is outlined as well.  相似文献   
3.
This publication continues previously published work from the authors which evaluates the storage potential of poultry fat for its use as an unmodified biofuel in heat and steam generating systems [1]. The previous work examined the physical properties of these fats while this study is concerned with chemical properties. In this study poultry fat (biofuel) and its 20%, 40%, 60% and 80% mixtures with #2 pump diesel fuel were stored for 1 year at bench scale (1L) under controlled laboratory conditions at 4, 38, 54.4 °C and at 22 °C. One hundred percent of poultry fat was studied under these same conditions with and without an antioxidant additive. Twenty and eighty percent of poultry fat mixtures were also stored at pilot scale (250 gallons) under outdoor, ambient conditions. Chemical properties relevant to the use of these mixtures as a biofuel for industrial boilers were studied and tracked. These properties include Energy Values (BTU), Ultimate Analysis (carbon, hydrogen, oxygen, ash, nitrogen, and sulfur), moisture, impurities, unsaponafiables (MIU), and Free Fatty Acid Content. Energy content of the biofuel samples dropped over the course of the study with untreated biofuel losing 18.9% of its BTU value over the course of a year. Ultimate analyses showed an overall increase in carbon composition and a decrease in oxygen content. Hydrogen levels increased in most treatments as did overall ash and sulfur percent composition. MIU values increased, this overall increase was attributable to variable increases in insolubles and unsaponifiables. Free fatty acid levels increased in all treatments. Most of the chemical changes observed in this study were reduced by the addition of antioxidant to 100% biofuel.  相似文献   
4.
The construction industry relies on skilled craft workers supplied through various training programs. Based on a nationwide survey of industry experts regarding craft training programs, this paper examines the current state and effectiveness of construction craft training via 93 respondents from a wide range of U.S. industrial and commercial construction firms and associated craft training centers. The study’s survey data allowed the writers to examine the major issues regarding craft training, such as the relative importance of basic core topics, training completion rates, the relation between trades’ engagement and training, and the barriers of advancing craft training in construction. The paper also uses the experts’ responses to estimate the benefits of craft training on productivity, turnover, absenteeism, safety, and rework. Various statistical methods are used to support the analysis. Problems are identified in craft training among the training programs examined and potential solutions for improving craft training effectiveness are suggested.  相似文献   
5.
A blood spot detection neural network was trained, tested, and evaluated entirely on eggs with blood spots and grade A eggs. The neural network could accurately distinguish between grade A eggs and blood spot eggs. However, when eggs with other defects were included in the sample, the accuracy of the neural network was reduced. The accuracy was also reduced when evaluating eggs from other poultry houses. To minimize these sensitivities, eggs with cracks and dirt stains were included in the training data as examples of eggs without blood spots. The training data also combined eggs from different sources. Similar inaccuracies were observed in neural networks for crack detection and dirt stain detection. New neural networks were developed for these defects using the method applied for the blood spot neural network development.The neural network model for blood spot detection had an average accuracy of 92.8%. The neural network model for dirt stained eggs had an average accuracy of 85.0%. The average accuracy of the crack detection neural network was 87.8%. These accuracy levels were sufficient to produce graded samples that would exceed the USDA requirements.  相似文献   
6.
Jansen  Bernard J.  Goodrum  Abby  Spink  Amanda 《World Wide Web》2000,3(4):249-254
The development of digital libraries has enhanced the integration of textual and multimedia information in many document collections. The World Wide Web provides the connectivity for many digital library users. Studies exploring the searching characteristics of Web users are an important and a growing area of research. Most Web user studies have focused on general Web searching, regardless of subject matter or format. Little research has examined how Web users search for multimedia information. Our study examines users' multimedia searching on a major Web search service. The data set examined consisted of 1,025,908 queries from 211,058 users of Excite ®, a major Web search service. From this data set, we identified and analyzed queries for audio, image, and video queries. Our findings were compared to results from general Web searching studies. Implications for the design of Web searching services and interfaces are discussed.  相似文献   
7.
The advent of the Internet and social media has revolutionized the way society communicates, the speed in which news is disseminated, and the approach that people take in their daily decision-making. Online reviews are now common place on nearly every consumer-related website. Consequently, attorneys are also being publicly scrutinized by their clients on a range of topics from price, competence, satisfaction, personality, communication, and effectiveness. On one side of the coin, this new phenomenon can be very rewarding since attorneys were previously limited to receiving a small number of referrals from the word-of-mouth promotion before the creation of online reviews. However, the exact opposite is true. Negative online reviews, whether accurate or not, may deter potential clients from even giving the attorney a second thought. As a result, a firm's business can feel the immediate impact of negative reviews. Attorneys, who legitimately need and want to protect their business and reputation, cannot speak freely online to defend their honor. Rather, an attorney must be mindful of not disclosing confidential client information or crossing other ethical lines that may then expose the attorney to potential discipline. There are several interests that must be considered such as allowing attorneys to exercise their First Amendment right to free speech, respect and adherence to the ethical rules of non-disclosure of confidential information, allowing attorneys to preserve their reputation, and protecting an attorney's marketability and means of generating income. This article explores the trend in offering reviews online in a variety of industries, including legal services, the statistical findings regarding the prevalence of this information and consumers' reliance on the information while making a purchasing decision. This article also considers the positive and negative implications of the reviews being so widely spread, while highlighting unique considerations as it relates to the practice of law and factors that may greatly skew a reviewer and reader's perceptions. Next, this article outlines the ethical considerations of attorneys if they want to respond to negative online feedback, such as disclosure of confidential information. Then, this article analyzes the American Bar Association (ABA) and several US states' ethics opinions for guidance for attorneys who wish to respond negative reviews. Finally, this article details the author's recommendations for attorneys, the ABA, and the US states and propose the areas where additional ethics opinions, rules and guidelines should be focused to establish a proper balance between the valuable insights discovered from a client's review and attorneys' legitimate interests in protecting their reputation and livelihood from inaccurate, malicious, or erroneous postings.  相似文献   
8.
There have been substantial changes in both material technology and construction productivity over the past several decades. By analyzing the changes in both material technology and productivity among 100 construction activities from 1977 to 2004, this research examines the strength and types of relationships that exist within these two occurrences. Through analysis of variance (ANOVA) and regression analyses, the researchers found that activities experiencing significant changes in material technology have also experienced substantially greater long-term improvements in both their labor and partial factor productivity. The research did find that a stronger relationship exists between changes in material technology and partial factor productivity than in labor productivity. The research also found that changes in the unit weight of materials had a significant relationship to labor productivity, while changes in installation and modularity had a significant relationship to partial factor productivity. The research findings will help industry practitioners to better understand how they may leverage technology to improve construction productivity, while also helping researchers understand the theoretical relationships between technology and construction productivity.  相似文献   
9.
10.
Equator crossing times for NOAA,ERS and EOS sun-synchronous satellites   总被引:1,自引:0,他引:1  
The local Equator Crossing Times (EXT) of the 13 National Oceanic and Atmospheric Administration (NOAA) platforms (TIROS-N and NOAA-6 through -17) flown from 1978 until the present have been summarized as a function of time and approximated analytically. The fit equations accurately reconstruct all past EXTs to within ±2 min and also allow extrapolation in time, thus providing a useful insight into the phenomenology of its evolution. The EXTs of the three European Research Satellites (ERS: ERS1, ERS2 and Envisat) and two Earth Observing System satellites (EOS: Terra and Aqua) are also presented. In contrast to the NOAA platforms, the ERS/EOS orbits are adjusted in-flight. This makes an analytical fit to the resulting man-made EXTs impractical, and less needed as the EXTs are more stable.  相似文献   
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