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In on-site measurement, as the transformer’s structure is often unknown, the application of frequency domain spectroscopy (FDS) is greatly limited in moisture assessment of transformer. This paper proposes a moisture assessment method for oil-immersed paper based on the dynamic characteristic frequency even for an unknown transformer structure. FDS tests are performed on the oil-paper insulation, corresponding oil-immersed paper, and mineral oil under different moisture conditions. The moisture criterion of oil-immersed paper and the influence of the structural parameters on the calculated frequency spectroscopy at different frequencies are discussed. It is concluded that the moisture criterion’s effectiveness, which indicates the sensitivity of assessed moisture content to the error of the tan $\delta $ , changes at different frequencies. Moreover, there are some frequencies at which tan $\delta $ is not influenced by structural parameters and is close to the measured value, which are regarded as “characteristic frequencies.” Based on the characteristic frequency, the moisture content of oil-immersed paper is assessed according to the frequency spectroscopy of oil-paper insulation without the structural parameters. The result shows that the assessing frequency changes under different moisture conditions, and the error of the assessed moisture content is less than 0.1%.

Working under PWM voltage with fast voltage rise time and high frequency, medium frequency transformers may suffer from overvoltage and temperature rise in the winding. As a result, partial discharge may be triggered with high probability, threating the insulation reliability. Therefore, it is necessary to evaluate the insulation capability of medium frequency transformers with respect to partial discharge and deterioration. This paper introduces a test system based on power electronic modules that can generate repetitive pulse voltage. Then, by using this system, partial discharge inception voltage test under different temperatures and endurance lifetime test are conducted on Nomex paper, which is an insulation material usually used in medium frequency transformers. The results show the change trending of the partial discharge inception voltage of Nomex paper with temperature and indicate an accelerated aging of this material with the presence of continuous discharge.

The existing plethora of document classification techniques exploits different data sources either from the content or metadata of research articles. Various journal publishers like Springer, Elsevier, IEEE, etc., do not provide open access to the content of research articles, whereas metadata is freely available there. Metadata like title, keyword, and abstract can serve as a better alternative to the content in various scenarios. In the current literature, researchers have assessed the role of some of the metadata individually. We believe that the collective contribution of metadata parameters can play a significant role in classifying research papers. This paper presents a comprehensive evaluation of the role of metadata, individually as well as in combinations to achieve the objective of research paper classification. Moreover, we have classified the research articles into ACM hierarchy root categories (e.g. general literature, hardware, software, etc.). In this comprehensive evaluation, we have assessed all the possible combinations of metadata features against different classifiers such as Random Forest, K Nearest Neighbor, and Decision Tree. The results of this research reveal that the title & keywords combination outperforms other combinations with an F-measure score of 0.88.

Cellulosic fibre composites from agriculture waste product bast fibre such Empty Fruit Bunch (EFB) oil palm has lower cost than normal softwood fibre and they are great alternative to be considered in insulation papermaking. For this purpose, EFB fibre, kenaf fibre and their blend were used to fabricate electrical presspaper samples through a laboratory papermaking process. The study of physical, mechanical and electrical properties such as cellulosic structure, tensile strength, AC voltage breakdown and lightning impulse breakdown strength were conducted according to the standard testing method of insulation IEC60243-1:2013. From this research, the physical structure, mechanical and electrical behaviour of mixed EFB and kenaf fibre insulation paper are comparable to Kraft paper and qualified the basic criterion to be an electrical insulation paper as required by IEC60641-2 standard. The purposes of this insulation paper produced is to be use in electrical transformers, therefore the same test should be repeated to the insulation paper that have undergone aging process at normal and accelerated operating temperatures.

Researchers face difficulties in finding relevant papers to their research interest as the number of scientific publication is rapidly increasing on the web. Scientific paper recommenders have emerged as a leading solution to help researchers by automatically suggesting relevant and useful publications. Several approaches have been proposed on improving recommender systems. However, most existing approaches depend on priori user profiles, and thus they cannot recommend papers to new user. Furthermore, the existing approaches utilize non-public contextual information, and thus it cannot adequately find similarities between papers due to copyright restrictions. Also, the existing approaches consider only single level paper-citation relation to identify similarities between papers. Considering the above challenges, this paper presents a collaborative filtering based recommendation approach for scientific papers that does not depend on priori user profiles and which utilizes only public contextual information. Using citation context, we utilized 2-level paper-citation relations to find hidden associations between papers. The rational underlying this approach is that, two papers are co-occurred with same cited paper(s) and two papers are co-occurring with same citing paper(s) are significantly similar to some extent. To evaluate the performance of the proposed approach, publicly available datasets are used to conduct extensive experiments. The experimental results demonstrate that the proposed approach has significantly outperforms the baseline approaches in terms of precision, recall, F1, mean average precision, and mean reciprocal rank, which are commonly used information retrieval metrics. The novelty of this study is that, with the proposed approach, researchers are able to find relevant and useful publications over the internet regardless of their previous research experiences and research area.

In paper production, a jumbo reel is cut into multiple intermediate rolls, and each intermediate roll is then sheeted as finished goods. This problem is called a cutting stock problem and is proven to be NP-hard. The objective is to minimize material waste or trim loss from all the cuttings. In the case that any intermediate roll is not entirely used for its associated order, the intermediate roll itself could turn to be a dead stock. We use the concept of universal sizes of intermediate rolls to eliminate the dead stock. A pre-defined number of universal sizes of intermediate rolls is to be used to serve all the orders. The problem is solved using Reinforcement Artificial Bee Colony algorithm with Integer Linear Programming subroutine. This proposed approach is then tested with a set of 1,055 orders and 127 different sizes of sheet papers from a paper manufacturer. The results reveal that our method outperforms other algorithms. Our method offers the total trim loss of 3.51%, compared to the trim loss reported by the industry of at least 5%. This approach not only reduces the number of partially cut rolls, but also decreases the number of the jumbo reels needed to serve all the orders. Therefore, both the inventory cost and material cost can be saved.

The power transformer is one of the most important equipments that has a critical role in good electrical power delivery. Ageing of paper insulation inside the transformer is irreversible and hugely related to the operation of power transformer. This study involved inspection data from in-service and out-of-service 150 kV power transformers provided by the Indonesian electric company. The degree of polymerization (DP) of the cellulose paper insulation and furanic compound in the insulating oil can be used to estimate the transformer's lifetime. In this study, the correlation between HI decreasing rate (HI dec_rate ) and the loading factor of 115 transformers historical data was observed. The DP of the transformer paper was predicted (DP pred ) using the ANFIS model using the dielectric characteristics and dissolved gases as input. The results show that the correlation between the DP pred decreasing rate (DP dec_rate ) and the loading factor is more significant than that between the HI dec_rate and the loading factor

Mineral oil has long been used as an insulating liquid in transformers. Natural ester-based oil is an alternative due to its non-toxic and biodegradable characteristics. Then this study compared the rate of degradation of accelerated thermal aging paper impregnated in natural ester oil (NE) with mineral oil (MO) and Gas-to-Liquid (GTL). Sealed glass bottles containing thermally upgraded kraft paper (TUK), kraft paper (KP), pressboard (PB), and oil in an atmospheric environment were aged in an oven at 150 °C within 1344 hours. Observations were made at intervals of 336 hours during the aging. The rate of degradation of the paper was observed through the Degree of Polymerization (DP) test of kraft paper, while the chemical structure of the paper was observed through the Fourier Transform Infrared (FTIR) test of the paper. In addition, acid and moisture tests were also carried out to observe the oil-paper interaction during aging. The depolymerization rate of paper in natural ester oil is smaller compared to other oils. This indicates that NE has better thermal stability and can extend life of the transformer paper. The paper aging rate in MO is similar to GTL Oil because they both are hydrocarbons-based.

Most insulation in the power transformers consists of oil and cellulose (paper/pressboard). Mineral oil has been used as an insulating liquid for over a hundred years. However, mineral oil is a non-biodegradable oil and has a serious impact on the environment and the non- renewable energy resources. Therefore, it is important to replace this oil with another alternative insulating liquid, and PFAE was introduced in the year 2006 in Japan. In addition, the ability of an insulating system also depends on the thickness of the monomolecular cellulose fiber on the kraft paper. Hence, it is necessary to determine the appropriate thickness of kraft paper for use as an insulator on the power transformer for this type of oil. This project presents paper-oil (PFAE) charging and discharging current characteristics. The study was carried out through the implementation of experiments in the laboratory. Polarization and Depolarization Current (PDC) test has been carried out to test the conductivity and response function of the insulating materials. It was found that the thickness of kraft paper affecting the capacitance value and the PDC measurement of the tested model. In both dry and wet conditions, the sample of two layers of kraft insulation paper shows the best insulation status as it has the lowest conductivity compared to the other samples. It can be concluded that it is necessary to determine the ideal thickness of insulating paper to ensure that the power transformer has the best insulation.

The explicitly numerical or well-defined correlations between the dielectrics responses (DRs) and dielectric essences of oil-impregnated paper (OIP) insulation have not been fully understood yet. As a result, it is rather difficult to quantitatively diagnose the critical insulation condition, like determining moisture content in insulation paper (MCP) of power equipment only using electrical-based techniques such as frequency domain spectroscopy (FDS). To obtain MCP value, from a new perspective of parametric study on the circuital DR equivalence of OIP insulation-extended Debye model (EDM), the present contribution introduces a novel approach by exploring the pattern when EDM parameters vary with MCP and temperatures T. Further, mathematical correlations are developed between sensitive R-C values and MCP-T values. On the above analysis, small-scale physical models of real-life transformer bushings were prepared as test samples. Their OIP condenser bodies were artificially absorbed different controlled quantities of moisture and conditioned at different temperatures to record corresponding FDS results. Then a hybrid genetic algorithm combined with the Levenberg-Marquardt algorithm was proposed to estimate the EDM parameters by fitting the measured FDS data. Sensitive parameters therein were identified using subspectrum decomposition and formulated with MCP-T values so that a reliable moisture content estimation can be achieved once the testing temperature and FDS recordings of an insulation body are known.

Trap plays an important role in the charge transportation of three-layer oil-paper and the investigation of trap parameters at different degradation degree is of great significance for further research of the partial discharge (PD) mechanism. This article considers the turn-to-turn structure of on-board traction transformer. A defect model of three-layer oil-paper insulation was designed for PD test. The PD degradation samples are selected from the inception of PD to the breakdown of PD to study the characteristics of surface potential decay on degradation samples by using isothermal surface potential decay method. Given that, the trap distribution at different degradation stages was calculated and its influence on PD characteristics was investigated. The result shows that AC fluctuation voltages caused by inter-harmonic has a great influence on PD distribution, surface charge distribution and trap distribution. With the increase of degradation, the decay rate of surface potential increases and the decay rate of AC fluctuation voltages is larger than that pure AC. And also, the number of shallow trap with AC fluctuation voltages is larger than that with pure AC. The rate of free charge increases with the number of shallow trap increasing. More free electrons involves in the process of PD, accelerating the aging rate of three-layer oil paper samples. Therefore, it can be concluded that surface charge and trap distribution are helpful to clarify PD mechanism.

The oil-paper insulation system is widely used for the insulation purposes of power transformers as a result of its ability to withstand high thermal and electrical stresses. The presence of a gas cavity between impregnated papers layer is a serious problem. When localized breakdown takes place within this cavity, partial discharge (PD) occurs and ages the rest of the insulation system. This aging phenomenon declines the expected life time of the insulation system and subsequently the life time of the power transformers. Dissolved gas analysis is a recommended technique that is used in order to assess the state of the insulation system inside the transformers. In this paper, PD is recorded in the case of gas cavity presence between the layers of the impregnated papers under the effect of AC and DC voltage stress. This record is extended from the instance of PD inception until the breakdown of the whole insulation system. Furthermore, the concentration of the gases that dissolve in the insulating oil due to the aging of the impregnated paper is measured eight times during the record of the PD. Finally, the degradation of the insulating papers is studied optically through the use of a microscope at different stages of the aging test. Depending on PD measurements, dissolved gas analysis (DGA) results, and the optical study of the paper aging, the evolution of the aging of oil-paper insulation system as a result of internal PD is declared when AC and DC voltage stresses are applied. It is obtained that the aging evolutionary process totally differs with the alteration of the applied voltage.

An electrical tree discharge model of multilayer insulation paper was prepared, and a voltage of 20 kV was used for electrical tree cultivation and initiation tests. Based on the microscopic image information and partial discharge (PD) information during the aging of the electrical tree, the development of electrical tree discharges between layers of paper comprising epoxy resin-impregnated paper insulation was studied. The results show that, by analysing PD information such as the discharge volume phase spectrum and the discharge repetition rate phase spectrum, the development of the electrical tree branch progresses in four stages: initial, growth, stagnation, and bursting. During the growth and stagnation stages, the main discharge paths of the electrical tree are mainly formed, and there are many filamentous fibres on the path edge. During the burst stage, more branches will be formed on the electrical tree, which will cause the greatest damage to the insulation. With the extension of the electrical tree path, the discharge magnitude and discharge times also increase. There are specific discharge patterns in different growth stages of the electrical tree, and the number of discharge events in each positive half-cycle is significantly greater than that in a negative half-cycle. Combining the microscopic image information and PD information during the aging of such an electrical tree, a theoretical basis for evaluating insulation state by PD monitoring is realised. The long-chain molecules of cellulose and epoxy resin break bonds and oxidise, which decompose into a large number of free radicals, monosaccharides, and other low-molecular-weight products.

The low frequency section of frequency domain spectroscopy (FDS) of oil-paper insu- lation system can effectively reflect the ageing state and moisture of the oil-immersed paper. Meanwhile, steady-state insulation resistance is the one of indexes for the condition of transformer. In actual measurement, these two both are time-consuming and poor accessibility, thereby restraining their field applications. Aim at this problem, this paper analyses the polarization process of the oil-paper insulation in transformer, and adopts a low frequency equivalent circuit model for the oil-paper insulation to characterize the polarization process at low frequency. The simulated annealing particle swarm optimization (SAPSO) algorithm is proposed to identify the parameters in equivalent circuit, which are affected by change of insulation state. Compared with the experimental results, the errors of the steady-state insulation resistance and the tan δ below 10-3 Hz, which are calculated by the identified parameters, are less than 2.5%. This method can avoid the influence from external environment and reduce the measurement time. The time and frequency domain parameters calculated can provide reference for the ageing assessment of oil-immersed paper.

The Taguchi method was used to optimize the stack structure of electronic paper displays. The falling ball experiment was performed to analyze the effect of various combinations of cover lenses, optically clear adhesives, and substrates on the impact strength of the module surfaces. The results revealed that the stack structure considerably improved the surface impact resistance. The combination of a glass substrate electronic paper display and a plastic cover lens achieved the highest surface impact resistance.

The current study revolves around development of paper from dhaincha fiber (Sesbania aculeata). Dhaincha is a basically cultivated for improvisation of soil quality. Due to deforestation worldwide, various sources of raw materials are used in paper industries. Indian pulp and paper industry is the world's major paper industry. In this study extraction of dhaincha fiber was done followed by retting, combing, chemical analysis and by making of pulp with dhaincha fiber. The dhaincha pulp was then used for making a paper from dhaincha fiber. The thickness of the dhaincha paper was then tested with paper thickness tester. By doing further processing dhaincha paper can be used commercially by paper industry.

The NIST selection process for standardizing Post-Quantum Cryptography Mechanisms is currently running. Many papers already studied their theoretical security, but the resistance in deployed device has not been much investigated so far. In particular, fault attack is a serious threat for algorithms implemented in embedded devices. One particularly powerful technique is to use safe-error attacks. Such attacks exploit the fact that a specific fault may or may not lead to a faulty output depending on a secret value. In this paper, we investigate the resistance of various Post-Quantum candidates algorithms against such attacks.

In this work, Schottky diodes based on amorphous indium-gallium-zinc-oxide (IGZO) were fabricated on cellulose microfiber paper substrate. Silver lines used as the Schottky barrier were printed, in parallel to thermally evaporated Cr/Au ohmic contact, using a dispense printer. The morphological and electrical characteristics of the devices are presented. The fabricated diodes exhibited rectification ratios ranging from 3.4 to 34.9 at ±1V with ON voltages that range from 1.1V to 1.4 V, for device lengths (Ag to Au distance) from 145 µm to 894 µm. The diodes were characterized in a temperature range between 25°C and 80°C. They showed a decrease of the ON current when increasing temperature, which is mainly attributed to the change of the cellulose microstructure. Indeed, an opposite of the ON current behavior was registered when the diode was realized on a polyimide substrate. The realized flexible paper-based diodes offer a potential promising choice for printed environmental-friendly electronics.

The single-mode bosonic channel is addressed with classical interference in the modulation and with side information at the transmitter. This model can viewed as the quantum counterpart of the classical random-parameter Gaussian channel. Based on Costa's writing-on-dirty-paper result (1983), the effect of the channel parameter can be canceled even when the decoder has no side information, and regardless of the input power constraint. For both homodyne and heterodyne detection with a coherent-state protocol, the model reduces to a classical channel with either real or complex-valued Gaussian noise. Thereby, by applying Costa's dirty paper coding strategy, we observe that the effect of the classical interference can be canceled for those channels as well. Then, we consider the bosonic channel with joint detection, for which the classical results do not apply, and derive a dirty-paper coding lower bound. Furthermore, considering the special case of a pure-loss bosonic channel, we demonstrate that the optimal coefficient for dirty paper coding is not necessarily the MMSE estimator coefficient as in the classical setting.

The industry of disposables has undergone a huge revolution in this century owing to the busy lifestyles and technological advancements in its production and manufacturing process. Paper cups are one of the widely used products in disposable industry. It has multi utility options that is it can be used to drink water as well as beverages, soups, liquids etc. This paper entirely focuses on increasing the quality factor of production and manufacturing process of these paper cups by adding additional circuitry to the existing machinery to reduce waste of raw materials as well as the per unit cost involved in wastage of electricity. This research work is based on using proximity sensors to sense the materials and molded paper cups infront of machinery and reduce the electric wastage through a relay Mechanism assembly. This is a PLC based live project example of effectively increasing the overall efficiency of the manufacturing plant

Cortisol levels in saliva is an important biomarker of stress and its rapid detection is a significant need for overall management of health and wellness. Herein, we demonstrate two novel SERS-based approaches for the detection of cortisol directly in saliva using regular and novel hexagonal gold nanoparticles (AuNPs) on a paper substrate. Using the direct SERS method, we first show the detection of cortisol by mixing the cortisol solution with highly concentrated AuNPs on a Parchment paper surface as an active SERS substrate. We also propose an alternate lateral flow SERS (LFS) approach, which employs paper as a chromatographic channel to reduce interference from background saliva matrix for the detection using SERS. A rapid detection of spiked cortisol in saliva down to 100 µg/ml concentration by employing the ‘lateral flow SERS’ (LFS) platform is shown. Results indicate a promising route for point-of-care detection of stress biomarkers.

For the detection of product color uniformity and seam texture defects in the production process of test paper, detection methods are proposed respectively. For the detection of the color uniformity, a uniformity detection method based on dynamic light correction is proposed. The illumination correction image is used for color dynamic compensation of the test paper image to solve the influence of uneven illumination on the test paper. For the detection of texture defects such as seams, a texture defect detection method based on gray gradient aggregation intensity is proposed. This method uses one-way Gaussian convolution to strengthen features, and then calculates the gradient, divides the region and calculates the gradient extremum aggregation strength to judge texture defects, which can quickly and efficiently find seam defects. The experimental results show that the above methods have obvious effects on the color uniformity and seam detection of the test paper. The color uniformity accuracy rate is 96%, the seam detection accuracy rate is 97%. The total detection time of a single test paper is about 90ms. The algorithm is real-time and accurate, and can be used in actual production detection.

Ultraviolet (UV) irradiation was used as a tool Kraft paper. Using measurements of the DP as a function of irradiation time, a theoretical model was used to predict the local value of DP in the surface layer of the paper. After characterization of their mechanical properties, selected samples were exposed to oil flows mimicking ONAN, OFAF and reclamation conditions. The presence of a surface layer of low D Pled to significant surface roughening under high rates of oil flow,but no significant erosion. The findings indicate that the DP value at the surface is more critical than the average (or measured) D Pin determining the extent of oil flow related damage.

Life expectancy of power transformers is limited by the integrity of insulating cellulosic paper wound around transformer winding. The insulating paper is subjected to thermal, electrical and mechanical stresses. There are three main factors causing degradation in the paper, i.e. moisture, oxygen and temperature. In this work, the degradation rate due to temperature is only discussed. That means that transformer life could be shortened or extended by adjusting loads which results in higher or lower temperature conditions. The temperature, namely the hot-spot temperature is typically used to estimate the relative ageing rate and loss of insulation life. Being able to estimate the hot-spot temperature accurately given load and weather data helps operators to plan about transformer replacement properly. This could also reduce costs of early replacement due to a conservative estimation. In this work, thermal models have been developed using machine learning techniques to learn thermal behavior from historical data. The data are comprised of the hot-spot temperature estimated by winding temperature indicator (WTI), load profiles, ambient temperature, rainfall, wind speed and direction and solar radiation. The proposed method has been validated using data for five 400kV/275kV, four 400kV/132kV and two 275kV/66kV autotransformers and has been shown to work effectively.

Here, we report a preliminary analysis on the manufacturing and testing of a low-cost and eco-friendly paper-based gas sensors realized with Aerosol Jet Printing (AJP) and Flash Lamp Annealing (FLA). The hygroscopic properties of paper make it possible to detect the presence of water-soluble gases in an environment provided with a relative humidity (RH) above a given threshold $(\text{RH} > 75\%)$ . This aspect allows the usage of such technology in the realization of a future food smart packaging detecting the presence of a malevolent gas like ammonia in food. Carbon interdigitated electrodes were printed and sintered on chromatographic paper, obtaining a mean resistance value of to $(231\pm 20)\ \mathrm{k} \Omega$ and $(249\pm 28)\ \mathrm{k} \Omega$ for the left and the right electrode respectively. The sensors were tested at different relative humidity (RH) values (75, 80, 90, 100%), and once stabilized they were tested with different ammonia concentrations (3, 6, 9 and 12 ppm). A proportional decrease was evidenced in increasing RH and ammonia concentration. Considering the baseline at a constant value of $\text{RH} =75\%$ , the sensors showed a resistance decrease of 15% in presence of the lowest concentration of 3 ppm.

Oil-paper insulation is the key insulation structure of the transformers, whose aging condition is closely related to the operations of the equipment. The degree of polymerization (DP) is the direct parameter characterizing the aging condition of oil-paper insulation. Recently, the near infrared spectroscopy (NIRS) measurement powered by quantitative analysis is used to evaluate DP of the insulating papers mainly. While the applications of NIRS for DP evaluation is constrained because the present spectral quantitative analysis method is not accurate and stable enough, especially for onsite tests. In this paper, we propose a Gaussian process regression (GPR) method to predict DP of the oil- paper insulation in laboratory as well as in field. Firstly, the basic principles of GPR algorithm are illustrated. A GPR model for DP prediction is established based on the spectra of differently aged insulating paper samples which are prepared in laboratory. The GPR model show a high prediction accuracy both for training set and testing set. The established GPR model is finally applied on the DP prediction of insulating papers originating from a de-tanked transformer. The accurate predicted DP and the reliable aging assessment results indicate that the established model can be implemented on site.

Oil-paper insulation is an important component of the oil-immersed power transformer, and its insulation life is directly related to the operating life of the transformer. Therefore, it is particularly important to accurately assess the life of the oil-paper insulation system. In this paper, aging insulation paper samples with different mechanical stresses were prepared in an aging vibration chamber under laboratory conditions, and the activation energy under the synergistic machine-thermal action was obtained using the translation factor. The Arrhenius equation was then combined with the Ekenstam equation to derive an equation that can accurately determine the degree of polymerization of the oil-paper insulation system. It is proved that this equation can predict the degree of polymerization of the paper under the synergistic action of machine and heat, and can provide theoretical support for the evaluation of paper life.

Although testing software is paramount to safeguard our digitizing society, students are reluctant to consider a career in the field. A reason could be that dedicated courses on software testing are rare. However, even when such a course exists, students perceive testing as a boring, unrewarding and even dogmatic chore. For more than 10 years, we have been teaching a software testing course at the Vrije Universiteit in Amsterdam. Driven by our belief that an abundant exposure to software bugs makes good testers, we experimented with many ideas to engage students and make them love the topic. The most unorthodox, yet effective interventions we are proud of, were: (1) to scare students by analyzing past, software-related accidents, such as Therac-25 or Boeing 737-MAX; (2) to thrill them using bug-hunting gamification, enabled by the in-house developed VU-BugZoo; (3) to trust them an end-To-end testing of safety-critical software-intensive systems, such as model trains, automatic insulin pumps and even radiotherapy facilities, and (4) to inspire their career, by opening a dialog with test professionals from industry. The result is a mature course, read yearly by 50 computer science graduates, where almost 80% of the participants find the topic interesting and challenging, and 40% consider a future carrier in testing. These positive results make us confident that we found a formula that works. In this position paper, we would like to share our innovative ideas and lessons learned. Also in the future, we will stay committed to educate enthusiastic and responsible software testers.

In this paper, we obtain samples of thermal aging transformer insulation paper at 6 time points through an accelerated thermal aging test that simulates the actual operating state of the transformer. The Raman spectroscopy diagnosis model of transformer insulating paper aging is proposed. The model combines an autoencoder and a linear discriminant analysis algorithm to extract the characteristics of the Raman spectrum, and uses a Naive Bayes classification method to divide the aging stage of the insulating paper. Through the Raman spectroscopy diagnosis model of transformer insulation paper aging designed in this paper, the Raman spectroscopy characteristic quantity extracted by the AE-LDA method can effectively reflect the aging characteristic information of the insulating paper, and the Naive Bayes classification algorithm is used to predict. Research shows that the model has a high predictive accuracy for the assessment of the aging state of insulating paper, and can effectively diagnose the aging state of transformer oil-paper insulation. The Raman spectroscopy used in the diagnosis of the aging of insulating paper has good aging discrimination ability and good application prospects, and provides a new idea for the diagnosis of the aging state of transformer oil-paper insulation.

Because the traditional insulation paper state detection method has some shortcomings, this paper proposes a non-destructive detection method, which uses the texture feature value of insulation paper image to establish a relationship with the degree of polymerization (DP) of insulation paper state, and then indirectly estimates the aging state of insulation paper. Firstly, the insulation paper images in different aging states are collected, and the texture feature values of the images are extracted by gray histogram, gray level co-occurrence matrix and gray level run-length matrix; then, the texture feature values are selected by correlation; then, the validity of the selected texture feature values to represent the insulation paper state is verified by support vector machine (SVM); finally, the multiple linear regression method is used. The relationship between the degree of polymerization and the texture feature value is established and verified by the actual results. The results show that the texture feature value has a good fitting relationship with the degree of polymerization, which verifies the effectiveness of this method in evaluating the state of insulating paper.

The paper oil insulation in the power transformer is in a complicated environment, and the insulating paper will withstand the mechanical stress mainly of tensile stress. When the tensile stress and thermal stress coexist, it will have a certain impact on the aging life of the insulation paper. This paper carried out tensile-thermal joint aging experiment of insulating paper, and the change rule of the degree of polymerization of insulating paper during aging is obtained. The accumulative loss rate of polymerization degree of insulating paper under different aging conditions is calculated. Finally, the aging life of insulating paper under different tensile stress intensity and temperature is obtained by using the time-temperature superposition method combined with the influence factor of tensile stress.

The ageing status of the oil-paper insulation is closely related to the operation of the transformers. Recently, near infrared spectroscopy (NIRS) is used to identify the ageing condition of oil-paper insulation for it is a more rapid and nondestructive detection than the traditional viscometry method. However, the identification accuracy of existing quantitative analysis method of NIRS are still insufficient. This paper proposed an improved Linear discriminant analysis (LDA) method to classify the spectra and to identify the ageing condition of the insulating paper. Based on DP measurement, the insulating paper specimens prepared in laboratory are divided into varying ageing groups. The principle of LDA method is introduced. The classic LDA method has been applied to identify the ageing status of specimens respectively from 4 ageing groups and 3 ageing groups. The results show that LDA has a better performance in classifying four groups than three groups. To achieve an accurate ageing condition identification with balanced accuracy of the model and enough categories of ageing status, the improved LDA method is proposed. The identification results show that the improved method has satisfactory performance and indicates great application potentials in the ageing assessment of the oil-paper impregnated insulation.

In order to explore the effect of cationic nano-fibrillated cellulose (CNFC) doping on the electrical properties of oil-paper insulation under thermal aging conditions, insulating papers with concentrations of 0wt%, 3wt%, 5wt%, and 10wt% were prepared. After vacuum impregnation with insulating oil, an accelerated thermal aging test was carried out at 130°C for 20 days. The changes of volume resistivity, dielectric properties and electrical breakdown strength with aging time were measured and analyzed. The results show that: Compared with ordinary insulating paper, the volume resistivity and electrical breakdown strength of composite paper are improved, but the dielectric constant and dielectric loss are slightly increased. This article believes that by adding CNFC, the inner pores of the insulating paper are filled, the carrier mobility is reduced, and the electrical performance of the insulating paper is improved.

Power transformer is one of the key equipment of the power grid, and its operation reliability directly affects the safe and efficient operation of the power grid. The main cause of transformer accidents is insulation failure. Therefore, aging characteristics and mechanism of oil-filled transformer oil-paper insulation has important academic value as well as application significance. Based on the quantum chemical simulation, this paper systematically studies the physical parameters of the transformer insulating paper molecules and their dissociation process. The results showed that as for the cellulose molecule with a degree of polymerization of 10, the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital was 4.2038 eV. As for its repeating unit cellobiose, the 1,4-β-glycoside bond would be broken firstly, whose equilibrium bond length was 1.41813 A. Moreover, the bond energy was 54.18 kcal/mol, and the energy of the corresponding equilibrium configuration was -1298.2662 Hartree. Subsequently, the cellulose would generate a large amount of D-monoglucose monomer and some free radicals. The results in this paper contributed to establishing the model and the mechanism of oil-paper insulation aging process, and further identifying the aging degree of transformer and improving the reliability of transformer operation.

An emerging alternative to conventional Augmented Reality (AR) glasses designs, Beaming displays promise slim AR glasses free from challenging design trade-offs, including battery-related limits or computational budget-related issues. These beaming displays remove active components such as batteries and electronics from AR glasses and move them to a projector that projects images to a user from a distance (1-2 meters), where users wear only passive optical eyepieces. However, earlier implementations of these displays delivered poor resolutions (7 cycles per degree) without any optical focus cues and were introduced with a bulky form-factor eyepiece (50 mm thick). This paper introduces a new milestone for beaming displays, which we call HoloBeam. In this new design, a custom holographic projector populates a micro-volume located at some distance (1-2 meters) with multiple planes of images. Users view magnified copies of these images from this small volume with the help of an eyepiece that is either a Holographic Optical Element (HOE) or a set of lenses. Our HoloBeam prototypes demonstrate the thinnest AR glasses to date with a submillimeter thickness (e.g., HOE film is only 120 um thick). In addition, HoloBeam prototypes demonstrate near retinal resolutions (24 cycles per degree) with a 70 degrees-wide field of view., Comment: 15 pages, 18 Figures, 1 Table, 1 Listing

The life duration of cellulosic insulation is an essential aspect in the design of power transformer. Mineral oils have been largely used as liquid dielectrics to extend the service life of transformers. However the environmental and health aspects led to the seeking of alternative liquid dielectrics. Many authors have claimed that the use of bio-based liquids, especially natural esters can slow down the aging process of dielectric paper. The use of natural esters can therefore extend the actual operating life of transformers. Many vegetable oils have been elaborated. In this paper, we focus on palm kernel and castor oils, two non-edible vegetable oils largely present in Central Africa. We show the results of a study of thermal aging of dielectric paper immersed in palm kernel and castor oils. We start by presenting the elaboration and performance analysis processes of methyl esters of palm kernel and castor oils. Next, we develop the aging procedure; the paper was aged at 110°C during 100 hours, samples of oils and insulating paper were taken for analyses. The various tests performed included the determination of the total acid number, the UV-visible spectroscopy and the physical changes of the insulating paper. The results obtained with natural esters are compared to those obtained with mineral oil, which was used as a benchmark. The results obtained with palm kernel and castor oils confirms the excellent dielectric and cooling properties observed with other natural esters.

In the screening area of the paper mill has the high density impurities which are removed from the pulp and it is stored in the machine chest. The pulp in the machine chest is directly transferred to the head box without removing any medium density sand particles which affects the quality of the pulp. Only if the pulp entering the paper machine is clean and well-mixed with additives a good quality of paper will be produced. So in between the pulp tank and the pulp receiver a medium density cleaner is installed. The pulp in the machine chest is allowed to flow through the round hopper. Due to the circulatory motion and by centrifugal force the high density sand particles will settle in the bottom of the hopper. Due to the centripetal force the pulp is recovered from the hopper. The sand particles that settled in the bottom of the hopper are removed by the periodic opening and closing of the solenoid valves at regular interval of time. The medium density impurities are removed by creating hydro cyclone. These sequential operations are automated and controlled through PLC. So the overall plant efficiency is increased. Since the medium density impurities are removed this ensures the good quality paper production.

Electromagnetic Fault Injection (EMFI) is a well known method of introducing faults for security analysis of digital devices. Such faults can be seen as analogous to the faults which are known to naturally occur in digital devices, a known problem with designing safety-critical systems.Numerous standards have been developed for safety-critical systems, including the development of standards for increasing the rate of naturally occurring faults using particle sources. In this work, we demonstrate that desktop EMFI tooling can be used to accomplish similar testing, but with more control, effectively speeding up the evaluation process.We demonstrate using EMFI tooling for safety evaluation to recreate a highly publicized safety issue present in an automotive ECU – one that could not easily be recreated with other techniques.

In a modern society, seniors want to be a part of the digital world and the research in progress seeks to present whether through Serious Games can help their learning process and understanding of cybersecurity when online browsing, namely, deciding which actions to make when facing an eminent threat. this position paper aims to presents a new research on how Serious Games can help seniors to become more aware in the cybersecurity theme and how to be more careful when search the web. In this research the methodology apply is the Action Research, by identifying the problem –lack of knowledge that seniors have on the online threats and promoting an action –the Serious Game played to teach and motivate the senior to become safer online.