SELECTION OF FREE PARAMETER FOREL-2 ALGORITHM IN THE PROBLEM OF AUTOMATIC GROUPING OF INDUSTRIAL PRODUCTS BY HOMOGENEOUS PRODUCTION BATCHES

Исследуется проблема влияния полуавтоматического подбора свободного параметра в задаче автоматической группировки промышленной продукции по однородным производственным партиям полупроводниковых приборов, основанной на модели FOREL-2 для задач p-медиан и k-средних. The author considers the problem impact of semi-automatic selection free parameter in the problem of automatic grouping of industrial products by homogeneous production batches based on the FOREL-2 model. We provide a comparative automatic grouping quality assessment results with models of FOREL-2, p-median and k-means.

Multistage Acid Stimulation for ICD Screens Completion Using Straddle Packer and Real-Time Telemetry Coil Tubing

Inflow Control Devices (ICD) (Fig. 1) is a part of the well completion to help optimizing the production by equalizing the reservoir inflow. Multiple ICD can be installed in the completion at a long section, as each ICD going to partially choke the flow. Completing wells with ICD is one of the most common techniques that is used to maintain uniform production across multi-layer reservoirs. One of the challenges in such completions is to achieve a uniform matrix acid stimulation across these screens due to well deviation and length of the screens. In most cases an effective diversion method is required during acid treatment to ensure all the screens are treated uniformly for maintaining homogeneous production across the reservoir. Over the time, wells with ICD screens show decline in production due to plugged screens which necessitates immediate action. In most cases remedy is to acid treat all ICD screens on individual basis using straddle packer System and real-time telemetry coil system due to requirements of diversion method, criticality of the packer setting depth and downhole pressure monitoring. Multistage acid stimulation for ICD screens is achieved using straddle packer's system with real-time telemetry coiled tubing (CT). The real-time telemetry coil system ensures depth accuracy – as each ICD port length is not more than couple of inches – and monitoring of pressures and straddle packer system's integrity during multistage acid stimulation across the horizontal screens. This operation involves challenges of properly setting the packer to selectively treat each ICD screen by mechanically diverting the acid treatment while maintaining seal integrity in each stage and re-using it multiple times. After drifting and wellbore conditioning run, the multi-set straddle packer system is deployed on real-time telemetry coil (fiber-optic enabled) for multistage acid treatment. Starting from total depth, the real-time CCL readings are utilized successfully to identify the first screens joint allowing the packer system to be stationed across the required screen. The packer elements are then energized to divert the acid treatment fluid into the targeted screen Thru the coil and exiting from per adjusted nozzles between the Packers; this diversion is confirmed by monitoring bottom hole pressure inside and outside the coil tubing string. Upon completion of the acid treatment of the ICD screens the tension-compression sub of telemetry coil system confirmed the elements is de-energized to make safe to move the packer without damaging the elements. The treatment is then successfully repeated across the remaining ICD screens with positive indication of diversion across each ICD screen. This study illustrates how the combination of the straddle packer System and downhole real-time telemetry system was utilized to successfully acid stimulate up to 38 stages and monitor the behavior of straddle packer continuously during diversion of multistage acid treatment of screens while maintaining packers seal integrity and downhole pressures. In addition, the study also provides lessons learned from implementation of multi-stages packers with real-time telemetry for successful diversion of acid treatment uniformly across the screens in horizontal well.

Optimal Growth in Two-Sided Markets

We develop a theoretical model of optimal growth in two-sided markets. The model posits that market output (number of transactions) is a function of the stock of supply and demand. This market output is modeled using a homogeneous production function, which can have increasing or decreasing returns to scale. The supply and demand stock levels follow a growth model in which the rate of growth at each point in time is a function of both the surplus each side of the market receives and the attrition of supply and demand (supply and demand lifetimes). The surplus can be apportioned between the two sides of the market by changing the price paid to sellers and the price charged to buyers, which we assume the platform controls. Through these price levers, the platform can pay subsidies to one or both sides of the market. We investigate the behavior of optimal market growth, including the point at which the market becomes self-sustaining and the long-run optimal size of the market. We characterize the optimal balance between supply and demand as the market size grows and determine optimal subsidy policies that maximize discounted total profit. For the case of both increasing and decreasing returns without price constraints, we show the optimal policy is to grow using an impulse of subsidy spending (a subsidy shock) to move the market immediately to its optimal long-run size. This result is consistent with the race to growth observed in many two-sided markets like ride-sharing. This paper was accepted by Gabriel Weintraub, revenue management.

Yardstick Regulation in a Competitive Context? The Case of the Italian Airports

Over the past years, airport regulation has been generating a lot of interest in Europe, and despite the passing of Airport Charges Directive in 2009, there is ongoing debate on the need for introducing tighter airport regulations. The aim of the paper is twofold. First, acknowledging that regulation is usually applied in markets where competition is weak or absent, we evaluate the ex-ante need for price regulation in the air transport industry. By focusing on the Italian airport industry, our analysis provides evidence of a high level of competitive pressure faced by airports (both inside and outside the industry), suggesting that tighter price regulation may not be the optimal solution. Second, assuming that stricter regulation of the airport industry is necessary, we empirically investigate the applicability of yardstick regulation to the Italian airport system, outlining critical challenges and issues that may arise when applying benchmarking techniques in setting the optimum level of efficiency at regulated airports. According to current literature, applicability of empirical benchmarking techniques requires some basic research requirements to be met, such as high-quality data, a homogeneous production function, and a sufficient number of comparable observations. We find that both heterogeneity and the relatively small number of comparable airports, along with the complexity of gathering proper data, may compromise the applicability of a regulation scheme based on yardstick principles at the national level.

Coleoborers (Curculionidae: Scolytinae) in native and homogeneous systems of Brazil nut (Bertholletia excelsa bonpl.) in the Southern Amazon, Brazil

Brazil nut is one of the most important species of the Amazon due to its socioeconomic importance. Especially in homogeneous production systems, it may be susceptible to damage by wood-boring insects, as by the subfamily Scolytinae (Coleoptera: Curculionidae); thus, inadequate management conditions can cause economic damage. Therefore, the objective of the present work is to evaluate the occurrence of wood-boring insects (Curculionidae: Scolytinae) in native and homogeneous systems of Brazil nut in the Meridional Amazonian, Brazil. The study was conducted in three environments: Conserved Native Planting nut, Anthropized Native Planting nut and Homogeneous Planting nut. Twelve ethanol traps were installed in each environment during four sampling periods. The data were submitted to entomofaunistic analysis, Pearson’s correlation analysis and cluster analysis. A total of 2,243 individuals from 31 species were sampled, of which 23 were from the Anthropized Native Planting nut, 24 from the Homogeneous Planting nut and 26 from the Conserved Native Planting nut. In the faunistic analysis, we highlight the species Xyleborus affinis (Eichhoff, 1868), which was the most representative one in the three environments and a super-dominant species in all four sampling periods. There was a greater similarity between the Anthropized Native Planting nut and the Conserved Native Planting nut; these two environments showed dissimilarity with the Homogeneous Planting nut. Monitoring coleoborers in Brazil nut agroecosystems is fundamental for the establishment of integrated pest management strategies.