ESFK 20-100 watt S-band amplifier

Electrostatically focused klystron development for use in interplanetary spaceborne communication system

ESFK 20-100 watt S-band amplifier Quarterly report

Electrostatically focused klystron tube modification

Evaluation of a pulsed quasi-steady MPD thruster and associated subsystems

The performance of quasi-steady magnetoplasmadynamic (MPD) thrusters at high power levels is discussed. An axisymmetric configuration is used for the MPD thruster, with various cathode and anode sizes, over a wide range of experimental conditions. Thrust is determined from impulse measurements with current waveforms, while instantaneous measurements are made for all other variables. It is demonstrated that the thrust produced has a predominately self-magnetic origin and is directly proportional to the square of the current. The complete set of impulse measurement data is presented

Statistical analysis of the impact of class imbalance on model performance

Abstract. This work studies the impact of class imbalance in data distribution on models and performance metrics. With the increasing amount of data available, new challenges arise, and one of them is unbalanced data. This problem occurs when one class in a dataset is underrepresented compared to others. The under-represented class is called the minority, while the dominant class is called the majority. In an unbalanced data problem, the number of instances in the minority class is much fewer than that in the majority class, with a ratio such as 1:99. The thesis begins with a comprehensive overview of the challenges and solutions associated with unbalanced data in machine learning. Different types of class imbalances have been defined and discussion of challenges from this issue. Next the thesis discusses various techniques for dealing with unbalanced data, including resampling and more complex algorithms such as XGboost. The thesis also presents an empirical study and results on the Caravan insurance dataset. This dataset was provided in the Coil Challenge in 2000, where participants competed to develop the best model to predict whether a customer would buy insurance for their caravan. The Caravan dataset shows that only around six percent of customers will buy insurance, making it heavily unbalanced. With this distribution, the dataset is a good candidate to study the impact of imbalance on model performance and performance metrics. Unbalanced data can cause problems in various industries, from fraud detection to credit risk management. Therefore, understanding how to deal with this issue is crucial for developing accurate machine learning models that can be used effectively across different domains. This work provides valuable insights into how to address this challenge by presenting empirical evidence and discussing commonly applied solutions. It is a helpful resource for anyone interested in machine learning and data science. Using a real business data set for empirical test, there are three findings from this research. Firstly, performance metrics such as accuracy may not be suitable for heavily unbalanced data. Secondly, most common modeling method, logistic regressions may not provide best results for minority class since performance metrics are dominated by majority class. Finally, to address imbalance issue, both resampling techniques to balance data before modelling and ensemble modelling methods such as XGBoost can produce good results.Tilastollisen aineiston todennäköisyysjakaumien luokittaisen epätasapainon vaikutuksia tilastollisten mallien ennustekykyyn. Tiivistelmä. Pro gradu -tutkielmani tavoitteena on tarkastella tilastollisen aineiston todennäköisyysjakaumien luokittaisen epätasapainon vaikutuksia tilastollisten mallien ennustekykyyn. Liiketaloudelliseen aineistoon perustuvan empiirisen tutkimuksen tuloksena saatiin kolme keskeistä tulosta. Ensiksi tilastollisten mallien arvioinnissa ennustekyvyn mittarit eivät sovellu luokittaisesti epätasapainoisiin aineistoihin. Toiseksi yleisimpiin käytössä oleviin tilastollisiin malleihin kuuluva logistinen regressioanalyysi aliarvioi havaintomäärältään pienimpien osajoukkojen esiintymisten todennäköisyyttä. Kolmanneksi luokittaisesta epätapainosta aiheutuvaa tilastollisen mallin ennustetarkkuuteen liittyvää virhettä voidaan merkittävästi parantaa XGBoostmallinnustekniikalla ja resampling-menetelmillä

Improvement of thermally formed nickel silicide by ion irradiation

A significant improvement of the lateral uniformity of thermally formed Ni_(2)Si layers has been observed after low‐dose (10^(13)~3 × 10^(14) ion/cm^2) Xe irradiation of an As‐deposited Ni film. Measurements have also been made on samples that contained a thin impurity layer formed intentionally between the silicon substrate and the evaporated nickel film. The impurity layer was thick enough to prevent thermal silicide formation in unirradiated samples, but in irradiated samples, the silicide formation was not prevented. Similar results were obtained for As implantations. We attribute this effect to ion mixing of the interfacial layer. These results demonstrate that a low‐dose irradiation can render the process of silicide formation by thermal annealing more tolerant to interfacial impurities. The concept is of potential significance to VLSI technology

Sensitivity limits of a Raman atom interferometer as a gravity gradiometer

We evaluate the sensitivity of a dual cloud atom interferometer to the measurement of vertical gravity gradient. We study the influence of most relevant experimental parameters on noise and long-term drifts. Results are also applied to the case of doubly differential measurements of the gravitational signal from local source masses. We achieve a short term sensitivity of 3*10^(-9) g/Hz^(-1/2) to differential gravity acceleration, limited by the quantum projection noise of the instrument. Active control of the most critical parameters allows to reach a resolution of 5*10^(-11) g after 8000 s on the measurement of differential gravity acceleration. The long term stability is compatible with a measurement of the gravitational constant G at the level of 10^(-4) after an integration time of about 100 hours.Comment: 19 pages, 20 figure

A search for interstellar molecules in the spectra of highly reddened stars

A total of ten stars were observed with cameras of the International Ultraviolet Explorer (IUE) in both high and low dispersion. One star, X Persei (HD 24534, 6.0 BE), was analyzed in detail. Ultraviolet observations of the column densities of CO match those derived from the radio to within a factor of 4, with the difference probably due to the larger beam size of the radio measurement and the assumption of a thermal population in the rotational levels of CO. Upper limits are given to the log column densities for OH, HCl, and CH2 of 14.0, 12.3 and 12.8. The carbon abundance was found to be about solar with a possible depletion of about a factor of 2. With precautions concerning both noise and correct background, the IUE can be used for studies of interstellar molecules

Hazard Analysis Critical Control Point (HACCP) Sebagai Model Kendali Dan Penjaminan Mutu Produksi Pangan

This research is basically based on the premise that food security especially in the field of pastry making into something very important. The purpose of this study are: 1) to analyze important stages in the processing of pastry to ensure the quality of pastry; 2) Evaluate how the supervision and quality control in the processing of pastry, and 3) evaluate the basic feasibility and level of implementation of HACCP Processing Unit pastry. This research use descriptive method. In collecting observations and interviews. The results give an idea as follows: 1) The stages in the processing Pastry has adopted 7 principles of HACCP; 2) Supervision and quality control in the manufacture of pastry is in compliance with the HACCP concept, 3) the basic feasibility and level of implementation of HACCP in the processing of consecutive Pastry as follows: good, good and excellent

Analisis Keseimbangan Lintasan untuk Menciptakan Proses Produksi Pump Packaging Systems yang Efisien di PT. Bumi Cahaya Unggul

Ketidakseimbangan dalam pembagian beban kerja dengan adanya waktu tugas stasiun kerja yang menjadi bottleneck dapat mengakibatkan terjadinya peningkatan balance delay yang merugikan Perusahaan. Tujuan dalam penelitian ini adalah membuat keseimbangan lintasan untuk menciptakan proses produksi pump packaging systems yang efisien, dengan adanya perbaikan cycle time yang lebih singkat, peningkatan efisiensi lintasan produksi, mengurangi kerugian keseimbangan, meminimasi idle time dan peningkatan kapasitas produksi. Metodologi yang digunakan untuk memecahkan permasalahan adalah line balancing dengan menggunakan pendekatan metode Ranked Position Weight dan Heuristic Moodie-Young yang dilakukan dengan membuat pengaturan keadaan lintasan produksi untuk menciptakan pembagian beban kerja yang seimbang, sehingga setiap work station diharapkan mempunyai waktu tugas yang sama. Penelitian ini dilaksanakan di PT. Bumi Cahaya Unggul sebuah Perusahaan penyedia pompa. Hasil penelitian ini adalah tingkat efisiensi proses produksi Perusahaan masih belum optimal, ditandai dengan terjadinya ketidakseimbangan pembagian beban kerja akibat dari waktu tugas stasiun kerja yang menjadi bottle neck. Melalui penerapan metode line balancing, Ranked Position Weight dan Heuristic Moodie-Young dapat memberikan hasil yang signifikan yaitu peningkatan efisiensi lintasan produksi dan peningkatan kapasitas produksi