Rogue components: their effect and control using logical analysis of data

There is a small subset of any repairable component population that can develop a failure mode outside the scope of the standard repair and overhaul procedures, which makes them “rogue”. When this happens, a Darwinian-like “natural selection” phenomenon ensures that they will be placed in the most disadvantageous position in the asset management program, negatively affecting multiple aspects of the operational and maintenance organizations. Rogue components have long plagued the airline industry and created havoc in their asset management programs. In this paper, we describe how these rogues develop, outline the natural selection process that leads to their hampering the asset management program, and examine some of the negative impacts that ensue. Then we propose a Condition based maintenance approach to control the development of these components. We explore the use of a supervised learning data mining technique called Logical analysis of data (LAD) in CBM for the purpose of detecting rogues within a population of repairable components. We apply the resulting LAD based decision model on an inventory of turbo compressors belonging to an airline fleet. Finally, we evaluate the applicability of LAD to the rogue component detection problem and review its efficiency as a decision model for this type of problem.     

Migration of minor actinides and lanthanides in fast reactor metallic fuel

Minor actinides (MA) and lanthanides (LA) migration to the cladding in fast reactor metallic fuel is a concern because of their reaction with the cladding material. MA and LA migration test results are analyzed and reactions with the cladding are characterized. Remedies for reducing MA and LA migration and reaction with cladding are reviewed. A possible method is proposed that includes the addition of a compound forming element such as indium or thallium in fuel. These elements preferentially form stable compounds with MA and LA and should therefore reduce migration of MA and LA. As an intrinsic solution to the issue, the feasibility of the use of U-Pu-Mo alloy as fuel is studied. Unlike U-Pu-Zr, U-Pu-Mo consists of a single phase at typical fuel operation temperatures, and should have negligible fuel constituent redistribution and reduce MA and LA migration.     

Bioequivalence of two brands of ciprofloxacin 750 mg tablets (Sarf and Ciprobay) in healthy human volunteers

An open, randomized, two-way crossover study was carried out in 28 healthy volunteers at Gulf Pharmaceutical Industries (Julphar), as a joint venture with Saqr Hospital, Ras Al-Khaimah, UAE. The two commercial brands used were Sarf (Julphar, UAE) as test and Ciprobay (Bayer AG, Germany) as reference product. The drug was administered to each subject with 240 mL of water after an overnight fasting in two treatment days separated by a one-week washout period. After dosing, serial blood samples were collected for a period of 24 hr and serum was separated and analyzed for ciprofloxacin using a sensitive, reproducible, and accurate high-performance liquid chromatography (HPLC) method with ultraviolet (UV) detection. Various pharmacokinetic parameters, including AUC0-t, AUC0-infinity, Cmax, Tmax, t1/2, and lambdaz, were determined from ciprofloxacin serum concentration-time profiles for both formulations and found to be in good agreement with reported values. The parameters AUC0-t, AUC0-infinity, and Cmax were tested for bioequivalence after log-transformation of data. No significant difference was found based on analysis of variance (ANOVA); the 90% confidence intervals (95.73-107.62%, 94.98-108.26%, 92.80-103.90% for AUC0-t, AUC0-infinity, Cmax, respectively) for the test/reference ratios of these parameters were within the bioequivalence acceptance range of 80-125%. Based on this data, it is concluded that both formulations are bioequivalent and are interchangeable in medical practice.     

Validation of chlorophyll-α concentration maps from Aqua MODIS over the Gulf of Gabes (Tunisia): comparison between MedOC3 and OC3M bio-optical algorithms

Few studies have focused on the use of ocean colour remote sensors in the Gulf of Gabes (southeastern Tunisia). This work is the first study to evaluate the ocean colour chlorophyll-a product in this area. Chlorophyll-a concentrations were measured during oceanographic cruises performed off the Gulf of Gabes. These measurements were used to validate satellite data acquired from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite. First, two atmospheric correction procedures (standard and shortwave infrared) were tested to derive the remote-sensing reflectance, and then a comparison between two bio-optical (OC3M and MedOC3) algorithms were realized using the in situ measurements. Both atmospheric correction procedures gave similar results when applied to our study area indicating that most pixels were non-turbid. The comparison between bio-optical algorithms shows that using the regional bio-optical algorithm MedOC3 improves chlorophyll-a estimation in the Gulf of Gabes for the low values of this parameter.     

A Framework for the Development of an Environmental Management System: A Case Study in a Thermal Power Plant

A framework for the development of an environmental management system that satisfies the requirements of the ISO 14001 standards is presented. The framework is developed for NB Power, a company producing electricity for the province of New Brunswick in Canada. A case study is carried out in a thermal power plant called Coleson Cove. An initial review of the existing environmental management programs is presented. The environmental policy is evaluated, and the environmental aspects and impacts of the plant's activities are identified and prioritized according to prespecified criteria of severity, frequency, degree of control, and existence of regulation. Environmental objectives and targets are set and recommendations are presented.     

Semi-blind amplify-and-forward in two-way relaying networks

This paper addresses the analysis of a two-way semi-blind amplify-and-forward (AF) relay network, in which the relay node requires partial instantaneous channel state information (CSI) to amplify the received signals. First, we derive the expression of end-to-end signal-to-noise ratio in dual-hop transmissions over independent and not necessarily identically distributed Rayleigh fading channels. Based on the opportunistic AF selection relaying, we define bounds of some metrics such as average sum-rate and outage probability. Furthermore, we provide exact and approximate expressions for the average symbol error rate. The obtained results show that the performance of the proposed system decreases slightly while the processing complexity is reduced significantly compared to those of CSI-assisted AF relay schemes. In order to prove the exactness of the proposed analysis, a selection of numerical results is provided.     

Dynamic theoretic proactive caching placement game for energy saving in H‐CRAN

Edge caching is an effective feature of the next 5G network to guarantee the availability of the service content and a reduced time response for the user. However, the placement of the cache content remains an issue to fully take advantage of edge caching. In this paper, we address the proactive caching problem in Heterogeneous Cloud Radio Access Network (H‐CRAN) from a game theoretic point of view. The problem is formulated as a bargaining game where the remote radio heads (RRHs) dynamically negotiate and decide which content to cache in which RRH under energy saving and cache capacity constraints. The Pareto optimal equilibrium is proved for the cooperative game by the iterative Nash bargaining algorithm. We compare between cooperative and noncooperative proactive caching games and demonstrate how the selfishness of different players can affect the overall system performance. We also showed that our cooperative proactive caching game improves the energy consumption of 40% as compared with noncooperative game and of 68% to no‐game strategy. Moreover, the number of satisfied requests at the RRHs with the proposed cooperative proactive caching scheme is significantly increased.