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91.
Due to its major advantages, service-oriented architecture (SOA) has been adopted
in various distributed systems, such as web services, grid computing systems, utility computing
systems and cloud computing systems. These systems are referred as service-based
systems (SBS). In order to effectively use these systems in various applications, one major
challenge which must be addressed is to manage the quality of services (QoS) to satisfy
users’ requirements. In SBS, multiple services are often hosted by the same server and compete
for the limited system resources of the server, such as CPU-time, memory and network
bandwidth. In addition, service compositions, resource status of servers, workflow priorities
and QoS requirements are usually dynamically changing in runtime. Hence, it is necessary
to have effective techniques to allocate the system resources to each service provided by a
server in order to satisfy the QoS requirements of multiple workflows in SBS. In this paper,
a resource allocation approach is presented to adaptively allocating the system resources
of servers to their services in runtime in order to satisfy one of the most important QoS
requirements, the throughput, of multiple workflows in SBS. 相似文献
92.
Effects of three‐dimensional virtual reality and traditional training methods on mental workload and training performance 下载免费PDF全文
Chin‐Jung Chao Sheng‐Yu Wu Yi‐Jan Yau Weng‐Yan Feng Feng‐Yi Tseng 《人机工程学与制造业中的人性因素》2017,27(4):187-196
Industries will implement effective training programs to improve training performance, and an ideal training performance occurs under proper mental workload (MWL). Virtual reality (VR) has recently been widely utilized in training; however, only a few studies have investigated its effects on MWL and training performance simultaneously. The purpose of this study is to investigate the effects of VR training and traditional training methods, such as technical manuals (TM) and multimedia films (MF), on training performance and MWL. The results of the performance measurement show that VR training is considered the best training method compared to TM and MF, particularly in the case of complex tasks. The results of physiological measurements (GSR [galvanic skin response], LF% [low frequency], and LF/HF [high frequency] ratio) show a significant difference between reading TM and using computer (MF and VR), wherein the latter has a lower MWL. However, no significant difference in subjective MWL assessment (NASA‐TLX [task load index]) and HF% measurement is found. 相似文献
93.
This paper presents a systematic methodology based on Taguchi methods to determine and optimize a machine vision system's capability. Seven factors were studied in anL
27(313) orthogonal array: lens type, color of the background, distance between two objects on the target, distance between the camera and the target, filter, lighting source, and angle between the optic axis of the camera and the surface of the target. The optimal factor-level combination was determined from the experiment results, and the response surface plots were provided for a user to choose an alternative. Because this Taguchi methods-based methodology is simple and effective, it is recommended for determining and optimizing a machine vision system's capability. 相似文献
94.
Suk Hoo Yoon Sun Ki Kim Kil Hwan Kim Tai Wan Kwon Yau Kun Teah 《Journal of the American Oil Chemists' Society》1987,64(6):870-873
Rice bran oil and double fractionated palm olein (DF palm olein) were heated at 180 C for 50 hr to measure lipid deterioration
in the oils. Free fatty acid content of both oils increased during heating; however, iodine value and smoke point decreased.
Solid fat contents of both oils were unaffected by heating time. Cloud point of rice bran oil was much lower than that of
palm olein. Color of oils changed gradually to dark brown from light yellow with increased heating time. Absolute content
of polyunsaturated fatty acid, such as linoleic acid, reduced more than that of monounsaturated fatty acid, such as oleic
acid, in both oils. In both oils, iodine value correlated very well with linoleic acid content, with correlation coefficient
higher than 0.96. 相似文献
95.
Lee AH Wang K Scott JA Yau KK McLachlan GJ 《Statistical methods in medical research》2006,15(1):47-61
Count data with excess zeros relative to a Poisson distribution are common in many biomedical applications. A popular approach to the analysis of such data is to use a zero-inflated Poisson (ZIP) regression model. Often, because of the hierarchical study design or the data collection procedure, zero-inflation and lack of independence may occur simultaneously, which render the standard ZIP model inadequate. To account for the preponderance of zero counts and the inherent correlation of observations, a class of multi-level ZIP regression model with random effects is presented. Model fitting is facilitated using an expectation-maximization algorithm, whereas variance components are estimated via residual maximum likelihood estimating equations. A score test for zero-inflation is also presented. The multi-level ZIP model is then generalized to cope with a more complex correlation structure. Application to the analysis of correlated count data from a longitudinal infant feeding study illustrates the usefulness of the approach. 相似文献
96.
Michael C. H. Hui Doris Yau 《Frontiers of Architecture and Civil Engineering in China》2011,5(4):405-414
The first “modern” type of vehicular bridge was built in Hong Kong China in the 1920s. The need for an efficient transportation system to cope with population growth and enable economic development has demanded the construction of more and more bridges since the middle of the 20th century. By 2007, Hong Kong had a total of about 1300 vehicular bridges. Four of these bridges, including the Tsing Ma Bridge, Kap Shui Mun Bridge, Ting Kau Bridge, and the cable-stayed bridge on the Hong Kong-Shenzhen Western Corridor, are considered to be major bridges supported by cables. Currently, the Stonecutters Bridge on Route No. 8 is under construction and is expected to be completed in late 2009. At the same time, the Hong Kong-Zhuhai-Macao Bridge will be in its detailed design stage soon. While efforts have been made by bridge builders to construct these giant structures, the upkeeping of these valuable assets at a high standard and ensuring their continuous functioning and performance during their intended lifespans will be another important task for bridge engineers. Wind and structural health monitoring system (WASHMS) will play a key role in this respect. 相似文献
97.
Y.H. Yau H.F. Wong N. Ahmad 《International Journal of Heat and Mass Transfer》2012,55(11-12):2879-2888
The physical processes of heat transfer are typically complicated in the curing of rubber. In this study, the image plot and the plot of the temperature profile were obtained in such an environment, and then compared with the finite element method (FEM), which is used in finite element analysis (FEA) software. A good agreement was observed, and the difference was less than 1% when evaluating the different curing conditions. This confirms that the correct curing time can be determined by studying the temperature profile, which will help to avoid the deterioration of the mechanical properties of thick rubber products. 相似文献
98.
In this work, we report the design, fabrication, and characterization of novel biochemical sensors consisting of nanoscale grooves and slits milled in a metal film to form two-arm, three-beam, planar plasmonic interferometers. By integrating thousands of plasmonic interferometers per square millimeter with a microfluidic system, we demonstrate a sensor able to detect physiological concentrations of glucose in water over a broad wavelength range (400-800 nm). A wavelength sensitivity between 370 and 630 nm/RIU (RIU, refractive index units), a relative intensity change between ~10(3) and 10(6) %/RIU, and a resolution of ~3 × 10(-7) in refractive index change were experimentally measured using typical sensing volumes as low as 20 fL. These results show that multispectral plasmonic interferometry is a promising approach for the development of high-throughput, real-time, and extremely compact biochemical sensors. 相似文献
99.
The dynamicity of available resources and network conditions, such as channel capacity and traffic characteristics, have posed major challenges to scheduling in wireless networks. Reinforcement learning (RL) enables wireless nodes to observe their respective operating environment, learn, and make optimal or near-optimal scheduling decisions. Learning, which is the main intrinsic characteristic of RL, enables wireless nodes to adapt to most forms of dynamicity in the operating environment as time goes by. This paper presents an extensive review on the application of the traditional and enhanced RL approaches to various types of scheduling schemes, namely packet, sleep-wake and task schedulers, in wireless networks, as well as the advantages and performance enhancements brought about by RL. Additionally, it presents how various challenges associated with scheduling schemes have been approached using RL. Finally, we discuss various open issues related to RL-based scheduling schemes in wireless networks in order to explore new research directions in this area. Discussions in this paper are presented in a tutorial manner in order to establish a foundation for further research in this field. 相似文献
100.
James H. Bannock Siva H. Krishnadasan Adrian M. Nightingale Chin Pang Yau Kevin Khaw Daniel Burkitt Jonathan J. M. Halls Martin Heeney John C. de Mello 《Advanced functional materials》2013,23(17):2123-2129
A method is reported for the controlled synthesis of device‐grade semiconducting polymers, utilizing a droplet‐based microfluidic reactor. Using poly(3‐hexylthiophene) (P3HT) as a test material, the reactor is shown to provide a controlled and stable environment for polymer synthesis, enabling control of molecular weight via tuning of flow conditions, reagent composition or temperature. Molecular weights of up to 92 000 Da are readily attainable, without leakage or reactor fouling. The method avoids the usual deterioration in materials quality that occurs when conventional batch syntheses are scaled from the sub‐gram level to higher quantities, with a prototype five‐channel reactor producing material of consistent molecular weight distribution and high regioregularity (>98%) at a rate of ≈60 g/day. The droplet‐synthesized P3HT compares favorably with commercial material in terms of absorption spectrum, polydispersity, regioregularity, and crystallinity, yielding power conversion efficiencies of up to 4% in bulk heterojunction solar cells with [6,6]‐phenyl‐C61‐butyric acid methyl ester. 相似文献