A Supervised Embedding and Clustering Anomaly Detection method for classification of Mobile Network Faults

The paper introduces Supervised Embedding and Clustering Anomaly Detection (SEMC-AD), a method designed to efficiently identify faulty alarm logs in a mobile network and alleviate the challenges of manual monitoring caused by the growing volume of alarm logs. SEMC-AD employs a supervised embedding approach based on deep neural networks, utilizing historical alarm logs and their labels to extract numerical representations for each log, effectively addressing the issue of imbalanced classification due to a small proportion of anomalies in the dataset without employing one-hot encoding. The robustness of the embedding is evaluated by plotting the two most significant principle components of the embedded alarm logs, revealing that anomalies form distinct clusters with similar embeddings. Multivariate normal Gaussian clustering is then applied to these components, identifying clusters with a high ratio of anomalies to normal alarms (above 90%) and labeling them as the anomaly group. To classify new alarm logs, we check if their embedded vectors' two most significant principle components fall within the anomaly-labeled clusters. If so, the log is classified as an anomaly. Performance evaluation demonstrates that SEMC-AD outperforms conventional random forest and gradient boosting methods without embedding. SEMC-AD achieves 99% anomaly detection, whereas random forest and XGBoost only detect 86% and 81% of anomalies, respectively. While supervised classification methods may excel in labeled datasets, the results demonstrate that SEMC-AD is more efficient in classifying anomalies in datasets with numerous categorical features, significantly enhancing anomaly detection, reducing operator burden, and improving network maintenance

Factors influencing consumers' intention to return the end of life electronic products through reverse supply chain management for reuse, repair and recycling

Resource depletion, population growth and environmental problems force companies to collect their end of life (EOL) products for reuse, recycle and refurbishment through reverse supply chain management (RSCM). Success in collecting the EOL products through RSCM depends on the customers' participation intention. The objectives of this study are: (1) To examine the important factors influencing customers' attitude to participate in RSCM; (2) To examine the important factors influencing customers' subjective norm to participate in RSCM; (3) To examine the main factors influencing customers' perceived behavioral control to participate in RSCM; (4) To examine the influence of attitude, subjective norms and perceived behavioral control on customers' participation intention in RSCM. The Decomposed Theory of Planned Behaviour (DTPB) has been chosen as the underpinning theory for this research. The research conducted employed the quantitative approach. Non-probability (convenience sampling) method was used to determine the sample and data was collected using questionnaires. Partial Least Squares-Structural Equation Modeling (PLS-SEM) technique was employed. A total of 800 questionnaires were distributed among customers of electronic products in Malaysia. Finally, the questionnaire was distributed among the customers in electronic retailer companies based on convenience sampling method. The empirical results confirm that consumers perception about the risk associated with EOL electronic products, consumers' ecological knowledge and relative advantages associated with reuse, repair and recycling can influence the attitude of consumers to return the EOL products for reuse, repair and recycling to producer

Association of Gestational Free and Total Triiodothyronine With Gestational Hypertension, Preeclampsia, Preterm Birth, and Birth Weight:An Individual Participant Data Meta-analysis

Context: Triiodothyronine (T3) is the bioactive form of thyroid hormone. In contrast to thyroid-stimulating hormone and free thyroxine, we lack knowledge on the association of gestational T3 with adverse obstetric outcomes. Objective: To investigate the associaiton of gestational free or total T3 (FT3 or TT3) with adverse obstetric outcomes. Methods: We collected individual participant data from prospective cohort studies on gestational FT3 or TT3, adverse obstetric outcomes (preeclampsia, gestational hypertension, preterm birth and very preterm birth, small for gestational age [SGA], and large for gestational age [LGA]), and potential confounders. We used mixed-effects regression models adjusting for potential confounders. Results: The final study population comprised 33 118 mother–child pairs of which 27 331 had data on FT3 and 16 164 on TT3. There was a U-shaped association of FT3 with preeclampsia (P = .0069) and a J-shaped association with the risk of gestational hypertension (P = .029). Higher TT3 was associated with a higher risk of gestational hypertension (OR per SD of TT3 1.20, 95% CI 1.08 to 1.33; P = .0007). A lower TT3 but not FT3 was associated with a higher risk of very preterm birth (OR 0.72, 95% CI 0.55 to 0.94; P = .018). TT3 but not FT3 was positively associated with birth weight (mean difference per 1 SD increase in TT3 12.8, 95% CI 6.5 to 19.1 g, P &lt; .0001) but there was no association with SGA or LGA. Conclusion: This study provides new insights on the association of gestational FT3 and TT3 with major adverse pregnancy outcomes that form the basis for future studies required to elucidate the effects of thyroid function on pregnancy outcomes. Based on the current study, routine FT3 or TT3 measurements for the assessment of thyroid function during pregnancy do not seem to be of added value in the risk assessment for adverse outcomes.</p

TSH and FT4 reference interval recommendations and prevalence of gestational thyroid dysfunction: quantification of current diagnostic approaches

Context Guidelines recommend use of population- and trimester-specific TSH and FT4 reference intervals (RIs) in pregnancy. Since these are often unavailable, clinicians frequently rely on alternative diagnostic strategies. We sought to quantify the diagnostic consequences of current recommendations. Methods We included cohorts participating in the Consortium on Thyroid and Pregnancy. Different approaches were used to define RIs: a TSH fixed upper limit of 4.0 mU/L (fixed limit approach), a fixed subtraction from the upper limit for TSH of 0.5 mU/L (subtraction approach) and using non-pregnancy RIs. Outcome measures were sensitivity and false discovery rate (FDR) of women for whom levothyroxine treatment was indicated and those for whom treatment would be considered according to international guidelines. Results The study population comprised 52,496 participants from 18 cohorts. Compared to the use of trimester-specific reference intervals, alternative approaches had a low sensitivity (0.63-0.82) and high FDR (0.11-0.35) to detect women with a treatment indication or consideration. Sensitivity and FDR to detect a treatment indication in the first trimester were similar between the fixed limit, subtraction and non-pregnancy approach (0.77-0.11 vs 0.74-0.16 vs 0.60-0.11). The diagnostic performance to detect overt hypothyroidism, isolated hypothyroxinemia and (sub)clinical hyperthyroidism mainly varied between FT4 RI approaches, while the diagnostic performance to detect subclinical hypothyroidism varied between the applied TSH RI approaches. Conclusion Alternative approaches to define RIs for TSH and FT4 in pregnancy result in considerable over- and underdiagnosis compared with population- and trimester-specific RIs. Additional strategies need to be explored to optimize identification of thyroid dysfunction during pregnancy

Defining gestational thyroid dysfunction through modified non-pregnancy reference intervals: an individual participant meta-analysis

Background: Establishing local trimester-specific reference intervals for gestational TSH and FT4 is often not feasible, necessitating alternative strategies. We aimed to systematically quantify the diagnostic performance of standardized modifications of center-specific non-pregnancy reference intervals as compared to trimester-specific reference intervals. Methods: We included prospective cohorts participating in the Consortium on Thyroid and Pregnancy. After relevant exclusions, reference intervals were calculated per cohort in thyroperoxidase antibody-negative women. Modifications to the non-pregnancy reference intervals included an absolute modification (per 0.1 mU/L TSH or 1 pmol/L FT4), relative modification (in steps of 5%) and fixed limits (upper TSH limit between 3.0 to 4.5 mU/L and lower FT4 limit 5-15 pmol/L). We compared (sub)clinical hypothyroidism prevalence, sensitivity and positive predictive value (PPV) of aforementioned methodologies with population-based trimester-specific reference intervals. Results: The final study population comprised 52,496 participants in 18 cohorts. Optimal modifications of standard reference intervals to diagnose gestational overt hypothyroidism were -5% for the upper limit of TSH and +5% for the lower limit of FT4 (sensitivity 0.70, confidence interval [CI] 0.47-0.86; PPV 0.64, CI 0.54-0.74). For subclinical hypothyroidism, these were -20% for the upper limit of TSH and -15% for the lower limit of FT4 (sensitivity 0.91, CI 0.67-0.98; PPV 0.71, CI 0.58-0.80). Absolute and fixed modifications yielded similar results. Confidence intervals were wide, limiting generalizability. Conclusion: We could not identify modifications of non-pregnancy TSH and FT4 reference intervals that would enable centers to adequately approximate trimester-specific reference intervals. Future efforts should be turned towards studying the meaningfulness of trimester-specific reference intervals and risk-based decision limits

A detailed study of row-trenched holes at the combustor exit on film-cooling effectiveness

To analyse the effects of cylindrical- and row-trenched cooling holes with an alignment angle of 90 degrees on the film-cooling effectiveness near the combustor end wall surface at a blowing ratio of 3.18, the current research was done. This research included a 3D representation of a Pratt and Whitney gas turbine engine, which was simulated and analysed with a commercial finite volume package Fluent 6.2.26. The analysis was done with Reynolds-averaged Navier–Stokes turbulence model on internal cooling passages. This combustor simulator was combined with the interaction of two rows of dilution jets, which were staggered in the streamwise direction and aligned in the spanwise direction. In comparison with the baseline case of cooling holes, using row-trenched hole near the end wall surface increased the film-cooling effectiveness 44% in average

A comparison of cylindrical and row trenched film-cooling holes on a combustor endwall surface at high blowing ratio

This study was done to study the effects of cylindrical and row trenched cooling holes with alignment angle of ±60 degrees at blowing ratio of BR=3.18 on the film cooling effectiveness near the combustor end wall surface. In this study, a three-dimensional representation of a Pratt and Whitney gas turbine engine was simulated and analysed with a commercial finite volume package FLUENT 6.2.26. The analysis has been carried out with Reynolds-averaged Navier-Stokes turbulence model (RANS) on internal cooling passages. This combustor simulator was combined with the interaction of two rows of dilution jets, which were staggered in the streamwise direction and aligned in the spanwise direction. In comparison with the baseline case of cooling holes, the application of row trenched hole near the endwall surface doubled the performance of film-cooling effectiveness

Effects of row trench holes geometries on an endwall cooling

Gas turbine industries try to extend the gas turbine engine performance. By using the well-known Bryton cycle, the combustor outlet temperature must be increased to have higher efficiencies. However, the turbine inlet temperature increment creates harsh environment for the downstream components of the combustor. This requires designing an efficient cooling technique in this area. In the traditional cooling system, the increase in blowing ratio enhances cooling effectiveness. But, the coolant does not well attach on the surface at higher blowing ratios. This necessitates restructuring the cooling holes. A useful way can be trenching cooling holes at the combustor end wall surface and the alignment of row trenched holes; however, this has not been seriously considered as a solution up to the present time. The major effects of cylindrical and row trenched cooling holes with alignment angle of 0, +60 and 90 degrees at blowing ration, BR=3.18 on the effectiveness of film cooling near the combustor end wall surface is a subject to study in detail. In the current study, researchers used a FLUENT package 6.2.26 to simulate a 3-D model of a Pratt and Whitney gas turbine engine. In this research, a RANS model was used to analyses the flow behaviour on the passageways of internal cooling. In the combustor simulator, the dilution jets and cooling flow staggered in the streamwise direction and aligned in the spanwise direction as well. In comparison with the baseline case of cooling holes, the application of row trenched hole near the endwall surface increased the effectiveness of film cooling from 75% to 100% for different trench cases

Life-cycle cost optimization of prestressed simple-span concrete bridges with simple and spliced girders

In this paper, determination of the design variable optimum values of simple and spliced pre-tensioned girders in bridges is addressed by considering the life cycle cost of the whole structure. To this end, a program called OBPG is written with FORTRAN, consisting of the analysis, design and optimization subroutines based on the feasible direction method. AASHTO principles are used, assuming initial values for the design variables such as the dimensions of the girders and the deck, and the strands number. Then, using the analysis outcomes and considering the design criteria, the total cost of the structure, including that of the girders and slabs concreting, pre-tensioning cables performance, reinforcement and frameworks, are minimized as functions of the design variables. Although the initial optimization cost using life cycle cost is slightly more than that using the initial cost, optimization of the life cycle cost proves to be more economical. Ultimately, a program capable of analyzing simple and spliced pre-tensioned bridge girders is developed which calculates the life cycle and gives an optimum design. © Shiraz University

Effect of High-Frequency Electric Resistance Welding (HF-ERW) Parameters on Metallurgical Transformations and Tensile Properties of API X52 Microalloy Steel Welding Joint

This study investigates the effects of frequency, compression force and Vee angle parameters of High-Frequency Electric Resistance Welding (HF-ERW) process on mechanical properties of API X52 microalloy steel welding joint. Therefore, API X52 microalloy steel sheets having thickness of 8 mm was provided to manufacture pipes with the diameter of 16”. with direct weld seams using the HF-ERW method. During the manufacturing process, frequency values of 150, 200 and 250 kHz, compression forces of 2, 4 and 6 mark and Vee angles of 3°, 5°, and 7° were adopted. After changing the welding parameters, from the welded pipes, tensile and Charpy impact test samples prepared to macroscopically evaluate the weld metal flow and examine the effects of these parameters on mechanical properties of the welded joints. According to the results, it was concluded that frequency of 150 kHz, the compression force of 4 mark and Vee angle of 5° yields best mechanical properties in the HF-ERW joint of API X52 microalloy steel