An annotated bibliography of GRASP – Part I: Algorithms

A greedy randomized adaptive search procedure (GRASP) is a metaheuristic for combinatorial optimization. It is a multi-start or iterative process, in which each GRASP iteration consists of two phases, a construction phase, in which a feasible solution is produced, and a local search phase, in which a local optimum in the neighborhood of the constructed solution is sought. Since 1989, numerous papers on the basic aspects of GRASP, as well as enhancements to the basic metaheuristic have appeared in the literature. GRASP has been applied to a wide range of combinatorial optimization problems, ranging from scheduling and routing to drawing and turbine balancing. This is the first of two papers with an annotated bibliography of the GRASP literature from 1989 to 2008. This paper covers algorithmic aspects of GRASP.     

Multi‐temporal analysis of MODIS data to classify sugarcane crop

This paper presents a feasibility study using multi‐temporal Enhanced Vegetation Index (EVI) from Moderate Resolution Imaging Spectroradiometer (MODIS) data to classify sugarcane crop. This study was carried out in São Paulo State which is the major sugarcane producer in Brazil, occupying more than 3.1 million hectares. Cloud‐free MODIS images (16 days mosaics) were acquired over a period of almost 15 months. Samples of sugarcane and non‐sugarcane were randomly selected and cluster analysis was performed to establish similar EVI temporal behaviour clusters. It was observed that EVI was sensitive to variations in land‐use cover mainly due to phenology and land management practices. Therefore, selection of sugarcane samples with similar EVI temporal behaviour for supervised classification was difficult due to both large planting and large harvesting periods. Consequently, cluster analysis was chosen to carry out an unsupervised classification. The best results were obtained in regions occupied by: natural and planted forest, soybean, peanuts, water bodies and urban areas which contrasted with the temporal‐spectral behaviour of sugarcane. The lowest performance was observed mainly in regions dominated by pasture, which has similar temporal‐spectral behaviour to sugarcane. This study provided useful information to define a MODIS image classification procedure for sugarcane crop for the whole State area based on the large amount of cloud‐free MODIS images when compared with other currently available optical sensors.     

Range query processing on single and multi GPU environments

Metric-space similarity search has proven suitable in a number of application domains such as multimedia retrieval and computational biology to name a few. These applications usually work on very large databases that are often indexed to speed-up on-line searches. To achieve efficient throughput, it is essential to exploit the intrinsic parallelism in the respective search query processing algorithms. Many strategies have been proposed in the literature to parallelize these algorithms either on shared or distributed memory multiprocessor systems. Lately, GPUs have been used to implement brute-force parallel search strategies instead of using index data structures. Indexing poses difficulties when it comes to achieve efficient exploitation of GPU resources. In this paper we propose single and multi GPU metric space techniques that efficiently exploit GPU tailored index data structures for parallel similarity search in large databases. The experimental results show that our proposal outperforms previous index-based sequential and OpenMP search strategies.     

Cost comparison of running web applications in the cloud using monolithic,microservice, and AWS Lambda architectures

Large Internet companies like Amazon, Netflix, and LinkedIn are using the microservice architecture pattern to deploy large applications in the cloud as a set of small services that can be independently developed, tested, deployed, scaled, operated, and upgraded. However, aside from gaining agility, independent development, and scalability, how microservices affect the infrastructure costs is a major evaluation topic for companies adopting this pattern. This paper presents a cost comparison of a web application developed and deployed using the same scalable scenarios with three different approaches: 1) a monolithic architecture, 2) a microservice architecture operated by the cloud customer, and 3) a microservice architecture operated by the cloud provider. Test results show that microservices can help reduce infrastructure costs in comparison with standard monolithic architectures. Moreover, the use of services specifically designed to deploy and scale microservices, such as AWS Lambda, reduces infrastructure costs by 70% or more, and unlike microservices operated by cloud customers, these specialized services help to guarantee the same performance and response times as the number of users increases. Lastly, we also describe the challenges we faced while implementing and deploying microservice applications, and include a discussion on how to replicate the results on other cloud providers.     

Uncovering ITIL claims: IT executives�� perception on benefits and Business-IT alignment

Over 45% of companies are estimated to use IT Service Management (ITSM) frameworks, yet, these frameworks can be imitated and hence the competitive advantage gained from these will quickly become obsolete. Therefore, research on the benefits of ITSM must focus on both operational and strategic benefits. An international survey of 441 firms was conducted to examine the benefits that IT Infrastructure Library (ITIL), the de-facto ITSM framework, provided to the IT organizations. The research focused on how (1) operational benefits, and, (2) strategic positioning of the IT organizations, specifically how the perceived level of Business-IT alignment maturity evolved as the adoption of ITIL increased. Results indicate that as the adoption of ITIL increased, the number of realized operational benefits increased, as well as the levels of maturity of the Business-IT alignment. This indicates that the further the implementation of ITIL the greater the operational and strategic benefits to the organization. Implications for practitioners and researchers are also discussed.     

Parametric study of acoustic focusing of particles in a micro-channel in the perspective to improve micro-PIV measurements

In this study, we propose a new technique to bring most of the particles in a horizontal plane at mid-height of a micro-channel in order to improve the quality of the micro-PIV measurements. The basic principle is to create a stationary acoustic wave along the channel height so that the resulting acoustic force moves the particles toward the pressure node. A parametric study has been carried out without mean flow to characterize the motion of the particles toward the nodal-plane. We found that focusing speed grows with the acoustic pressure amplitude, with the concentration of particles in the suspension and with the particles diameter. We also led a preliminary investigation of acoustic focusing together with a mean stationary flow. We still observed an important focusing of particles for low freestream velocities. Nevertheless, acoustic focusing is inefficient beyond a given critical freestream velocity U ₀ for a given set of acoustic parameters and a given type of particles. It was also shown that other phenomena, like clumps formation, can be observed without mean flow if the acoustic focusing lasts long enough.     

Incentive contrast in domestic dogs (Canis familiaris).

Dogs (Canis familiaris) trained to receive a preferred food (dry beef liver) from an experimenter learned to maintain a longer gaze on the experimenter than dogs receiving a less preferred food (dog pellets). Dogs downshifted from dry liver to pellets rejected food more frequently than nonshifted controls. Gaze duration also decreased in downshifted dogs below the level of a group always reinforced with pellets. In addition, downshifted dogs tended to move away from the experimenter, adopting a lying down posture. This phenomenon, called successive negative contrast, has been described in analogous experiments with a variety of mammalian species, but has failed to occur in similar experiments with nonmammalian vertebrates. Unlike similar previous observations, the present data were obtained in an environment involving interspecific communication. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Color measurement in hamburger buns with fat and sugar replacers

Substitution of fat and sugar in the diet has been the object of intense research as an effort to produce foods without these ingredients or with the reduction of the amount normally used. In this work, hydrogenated fat and sucrose in hamburger buns formulas were replaced by polydextrose (Litesse II^®), salatrim (Benefat^®), and sucralose (Splenda^®) and their effects on crust color were evaluated using response surface methodology (RSM). The results showed that the ingredients used had a great effect on L, a, b and ΔE values, but they can be used as an option to produce low calories baked products.