bluuebunny/crossref_metadata_2025 huggingface dataset:
Peningkatan Angka Kejadian Nyeri Kepala Primer Terhadap Kualitas Tidur Buruk Pada Mahasiswa Fakultas Kedokteran Universitas Nusa Cendana Tahun 2020
Authors: Landa Destrini Anjani , Sp.OT Dr. Su Djie To Rante, M. Biomed, , FISCM Dr. S.M.J. Koamesah., MMR.,MMPK FISPH.,
Published: March 2024

Abstrak

Latar Belakang : Menurut World Health Organization (WHO) sekitar 90% populasi dewasa di dunia setidaknya pernah mengalami satu kali nyeri kepala dalam satu tahun. Secara global, diperkirakan prevalensi nyeri kepala pada orang dewasa adalah sekitar 50-75% dengan rentang usia 18-65  tahun. Salah satu faktor resiko nyeri kepala adalah gangguan tidur. Frekuensi, intensitas dan onset nyeri kepala memiliki hubungan yang signifikan dengan kejadian gangguan tidur, termasuk mimpi  buruk, sulit untuk tertidur, terbangun terlalu  pagi dan  kualitas  tidur  yang buruk yang di sebabkan oleh perubahan neurotransmiter seperti serotonin dan melatonin yang menyebabkan gangguan pada irama sirkadian. Kelompok Mahasiswa Fakultas Kedokteran relatif rawan memiliki kualitas  tidur yang buruk. Hal ini dapat disebabkan oleh tingginya durasi dan intensitas belajar, pengerjaan tugas yang memerlukan tenaga dan konstentrasi ekstra.

Tujuan: Mengetahui hubungan kualitas tidur dengan kejadian nyeri kepala primer pada mahasiswa Fakultas Kedokteran Universitas Nusa Cendana tahun 2020.

Metode : Penelitian ini merupakan penelitian analitikal observasional dengan rancangan cross sectional yang dilakukan pada mahasiswa preklinik Fakultas Kedokteran Universitas Nusa Cendana  dengan cara pengisian kuesioner Pittsburgh Sleep Quality Index (PSQI) dan kuisioner Nyeri kepala primer. Teknik pengambilan sampel menggunakan stratified random sampling dengan jumlah responden 74 orang yang memenuhi kriteria inklusi dan eksklusi. Penelitian dianalisis secara univariat, bivariat menggunakan uji chi-square.

Hasil: Dari 74 responden, didapatkan hasil 54 responden (73%) mengalami memiliki kualitas tidur buruk dan 20 responden (27%) memiliki kualitas tidur baik. Dari 74 responden juga didapatkan 51 responden (68,9%) memiliki nyeri kepala primer dan 23 responden (31,1%) tidak memiliki nyeri kepala primer. Hasil uji analisis bivariat pada penelitiaan ini diperoleh hasil p=0,007 (p<0,05) dan nilai RR (Relatif Risk) untuk kualitas tidur yang buruk terhadap nyeri kepala menunjukan nilai sebesar 2,475 atau 2 kali (RR>1) yang memiliki makna bahwa variabel yang diteliti adalah faktor resiko.

Kesimpulan: Terdapat hubungan yang signifikan antara kualitas tidur dengan kejadian nyeri kepala primer pada mahasiswa Fakultas Kedokteran Universitas Nusa Cendana tahun 2020.

Kata kunci : Kulitas tidur,Nyeri kepala primer, Mahasiswa Kedokteran.
FAKTOR-FAKTOR YANG MEMPENGARUHI MOBILITAS ULANG-ALIK PENDUDUK DARI DESA OESAO KE KOTA KUPANG KECAMATAN KUPANG TIMUR KABUPATEN KUPANG
Authors: Wangga Dionisius , Samin Mikael , Rahmawati Arfita
Published: March 2024

This study aims to: (1) determine the effect of age on traders of agricultural products in Oesao Village to carry out shuttle mobility to Kupang City; (2) find out the effect of Distance on traders of agricultural products in Oesao Village, they carry out shuttle mobility to Kupang City; (3) find out the effect of income level on traders of agricultural products in Oesao Village, they carry out shuttle mobility to Kupang City; (4) determine the effect of land ownership on agricultural product traders, Oesao Village conducts shuttle mobility to Kupang City. This study used quantitative analysis descriptive method with a sample of 47 people. Data sources consist of primary data and secondary data collected by means of questionnaires and documentation. After that, the data processed through the process of editing, coding and tabulation. and analyzed by simple regression analysis method. The results of the analysis in the study show that: (1) the distance variable has no significant effect on the decision to carry out shuttle mobility from Oesao Village to Kupang Village with a significant value of 0.624 > 0.05; (2) The income level variable has a significant effect on the Round-trip Mobility Decision for agricultural product traders from Oesao Village to Kupang City with a significant value of 0.022 <0.05; (3) Age variable has a significant effect on the mobility decision of traders of agricultural products from Oesao Village to Kupang City with a significant value of 0.016 <0.05; (4) The variable of land ownership has a significant effect on the Round-trip Mobility Decision of traders of agricultural products from Oesao Village to Kupang City with a significant value of 0.049.
PENGARUH TINGKAT PRODUKTIVITAS HASIL TANI PADI TERHADAP KONDISI EKONOMI DI DESA BENU KECAMATAN TAKARI KABUPATEN KUPANG
Authors: Naisumu Mira Fransiska , Sunimbar Sunimbar , Manek Agustinus Hale
Published: March 2024

This study aims to determine (1) effect of factors for productivity of rice yields in Benu Village, Takari District, Kupang Regency (2) The effect of rice productivity on the economic condition of the community in Benu Village, Takari District, Kupang Regency. This research is a quantitative description research. The process of determining respondents in the study used random sampling with a total of 59 respondents. Data collection techniques in this study used two techniques, are questionnaires and documentation. The data analysis techniques used quantitative descriptive analysis techniques and simple regression analysis. Based on the research results, the geographical factors that affect the productivity of rice farming in Benu Village are climatic conditions, soil conditions, types of land and types of irrigation channels that play an important role in agriculture. The effect of rice productivity on economic conditions can be seen by the T test (partial test) it can be seen that the variable level of agricultural productivity (x) shows a significant value < (0.004 < 0.05) with a B value of -0.371 which means that the level of productivity rice farming has a positive and significant effect on economic conditions in Benu Village, Takari District, Kupang Regency. In the table of the coefficient of determination, it can be seen that the R value of 0.371 indicates that the effect of the level of productivity of agricultural products on economic conditions in Benu Village, Takari District, Kupang Regency is 37% while the remaining 63% is explained by variables that do not exist in the study such as employment status and other income. . And in the regression test a significant value of 0.004 <0.05 indicates a positive and significant influence on economic conditions in Benu Village, Takari District, Kupang Regency.
Loss Aversion Distribution: The Science Behind Loss Aversion Exhibited by Sellers of Perishable Good
Authors: Koh Daniel
Published: March 2024

This research introduces the concept of the loss aversion distribution, a pioneering framework designed for the analysis of consumer behavior. Departing from the conventions of traditional exponential models, this innovative approach incorporates a non-memoryless characteristic, which modulates the consumer's response to loss aversion throughout the product's life cycle. This modulation is achieved by a variable exponent influenced by the parameter $b$, representing the psychological impact of loss aversion, and the constant $k$, which reflects the market value of the good at the time of manufacture. Together, these parameters adeptly encapsulate the dynamic nature of consumer loss aversion from the moment of manufacture to the point of expiry. The model elucidates an initial muted response from consumers at the onset of ownership, which then intensifies during the mid-life cycle of the product, before ultimately diminishing as the product approaches its expiry. Through a meticulous derivative analysis of the probability density function, the study delineates the distribution's key properties, including its monotonicity, boundedness within the interval [0, 1], and its adherence to non-negativity. This framework not only enhances our comprehension of consumer behavior in relation to perishable goods but also paves the way for further investigations into psychometrics and the intricacies of loss aversion modeling.
A Tutorial on Bayesian Linear Regression with Compositional Predictors Using JAGS
Authors: Liu Yunli , Tong Xin
Published: March 2024

This tutorial offers an exploration of advanced Bayesian methodologies for compositional data analysis, specifically the Bayesian Lasso and Bayesian Spike-and-Slab Lasso (SSL) techniques. Our focus is on a novel Bayesian methodology that integrates Lasso and SSL priors, enhancing both parameter estimation and variable selection for linear regression with compositional predictors. The tutorial is structured to streamline the learning process, breaking down complex analyses into a series of straightforward steps. We demonstrate these methods using R and JAGS, employing simulated datasets to illustrate key concepts. Our objective is to provide a clear and comprehensive understanding of these sophisticated Bayesian techniques, preparing readers to adeptly navigate and apply these methods in their own compositional data analysis endeavors.
THE EFFECT OF COMPENSATION ON THE WORK PRODUCTIVITY OF SENAMAS ENERGINDO MINERAL EMPLOYES IN EAST BARITO
Authors: Ahmad Farhani
Published: March 2024

Increased productivity, which was carried out by the company for employees as a means of perfecting the human resource through the creation of motivation, is one of the factors that can directly influence employee productivity, and one way to motivate employees to increase the productivity of their work is by awarding appropriate compensation from the company. The purpose of this research is to find out and analyze the effect of compensation on employee productivity at PT. Senamas Energindo Mineral in Barito Timur. The research method used to use quantitative methods with a simple linear analysis tool with free variables is variable compensation and work productivity. Sample techniques used in this research were random sampling. Population: 627 employees of PT. Senamas Energindo Minerals, which samples as many as 86 employees. Based on the results of the research note that the positive effect of compensation against work productivity with the R Square of 0.353, meaning that contributions to the compensation effect on work productivity of 35.3% and the rest of 64.7% is affected by other variables. The implications of the research are that further internal research needs to be carried out by the company PT. Senamas Energindo Mineral in East Barito in terms of reviewing efforts to increase or maintain the level of employee work productivity at a level that is in line with the company's expectations to support the company's efforts in achieving its goals.
Keywords: Compensation, Work Productivity, Employee, Company
Managerial Ownership as a Controller of Earnings Quality in Jakarta Islamic Index 70
Authors: Paryati Retno
Published: March 2024

Profit is declared quality if it is consistent, does not fluctuate, and can predict the following year's profit. Companies with low levels of profit fluctuation pose managerial challenges because various factors influence the rise and fall of profitability. This research aims to determine the effect of earning Management on Earning Quality with Managerial Ownership as a Moderating Variable in Jakarta Islamic Index 70 (JII70) Companies for the 2019-2021 Period. This research uses the Moderated Regression Analysis (MRA) method in the form of panel data with purposive sampling techniques. The sample used was 18 companies registered in JII70 for the 2019-2021 period. The analytical methods used include descriptive statistical tests, stationarity tests, panel data regression tests, coefficient of determination (R2), F tests, T tests, classical assumption tests, and MRA tests. The research results show that the Earnings Management variable has a negative and significant effect on Earnings Quality. and the Managerial Ownership variable can moderate the influence of Earnings Management on Earnings Quality.
Selective phase transition of cholesteric blue phase I induced by pattern-controlled Grandjean–Cano disclinations
Authors: Nakajima Kazuma , Mitsuhashi Shogo , Ozaki Masanori
Published: March 2024

This study investigates the influence of Grandjean–Cano disclinations on the cholesteric-blue phase I (Ch-BPI) phase transition, revealing the pivotal role of defects in the phase transition of liquid crystals (LCs). We prepared the disclinations by wedge cells or parallel cells with an alignment pattern and demonstrated that the disclinations induce a phase transition in Ch-BPI. Furthermore, we demonstrated the control of the BPI appearance areas by utilizing this property. This defect-induced transition technique not only provides a novel method for controlling BPI orientation, but also offers insights into soft material crystal growth, suggesting potential applications in new BPLC-based device development.
Penerapan Strategi Pemasaran Pada Produk UKM Keripik Pare di Kecamatan Pasekan Kabupaten Indramayu
Authors: Yudianto Agus , Nurpratama Meddy , Firdaus Taufansyah
Published: March 2024

The need for healthy food is increasing along with population growth and increasingly limited agricultural land. However, many snack foods on the market contain additional ingredients that can be harmful to health. Therefore, healthy and nutritious snack products are increasingly needed. One interesting alternative is bitter melon chips, which are a snack product made from bitter melon, a plant that has high nutritional value. In an effort to publicize and market bitter melon chips, a business called Keripik Pare was founded by a group in West Java. The business proposal includes business ideas, capital, production planning, and marketing strategies to increase product competitiveness and business profitability and uses structured and effective implementation methods to produce quality products. By implementing SWOT analysis and the canvas business model, it is hoped that you will be able to identify business strengths, weaknesses, opportunities and threats, and design the right business strategy. In addition, the marketing strategy used includes market segmentation, determining market targets, and appropriate product placement. Through this effort, it is hoped that it can increase public awareness of the importance of consuming healthy food, create new jobs, and increase the income of local farmers.
Perbandingan Algoritma Support Vector Machine dan Random Forest untuk Analisis Sentimen Terhadap Kebijakan Pemerintah Indonesia Terkait Kenaikan Harga BBM Tahun 2022
Authors: Samantri Muhamad , Afiyati
Published: March 2024

The commodity of fuel oil (BBM) is the main commodity and the driving force of business. The increase in world oil prices is a threat to countries around the world, one of which is Indonesia. With the turbulent conditions in several countries, the Indonesian government decided to cut fuel subsidies which had an impact on price increases. The policy invited all Indonesian people and criticized it on various social media. The purpose of this research is to find out which algorithm has a better accuracy rate and to provide input to the government about public opinion regarding the increase in fuel prices in Indonesia. From the test results both work well, this is evidenced by the accuracy value obtained, where the support vector machine algorithm produces an accuracy value of 77%, while the Random Forest algorithm produces an accuracy value of 76%. So it can be concluded that the support vector machine algorithm has a fairly good accuracy rate compared to the Random Forest algorithm.
Penerapan Metode Extreme Learning Machine (ELM) untuk Memprediksi Hasil Sensor EWS Trafo
Authors: Apalem Rolisa
Published: March 2024

Early Warning System (EWS) Trafo merupakan alat monitoring secara konitinu untuk trafo yang memberikan peringatan saat terdeteksi anomaly, dengan tujuan mencegah ledakan. Alat ini menerapkan teknologi artificial intelligence dan machine learning untuk memantau dan memprediksi kondisi trafo secara real-time dengan menggunakan data sensor yang dikumpulkan oleh alat tersebut. Pada penelitian ini akan dilakukan prediksi kondisi trafo berdasarkan hasil sensor EWS Trafo dengan menggunakan metode Extreme Learning Machine (ELM). Diamana akan dilihat seberapa baik metode ELM dalam melakukan prediksi kondisi trafo. Berdasarkan hasil penelitian yang dilakukan terhadap beberapa kombinasi jumalah pembagian data training : testing dengan jumlah hidden layer, didapat nilai MAPE terendah ada pada kombinasi pembagian data 40%:60% dari total 470 data dengan hidden layer 20 buah yaitu sebesar 23,1125%. Sehingga dapat dikatakan bahwa metode Extreme Learning Machine (ELM) ini cukup baik dalam memprediksi kondisi trafo.
Specific features of the size structure of marginal populations of the nominative subspecies of the secret toad-headed agama (Phrynocephalus mystaceus mystaceus) (Agamidae, Reptilia)
Authors: Polynova G. V. , Polynova O. E.
Published: March 2024

The article considers the probability of Foster's  rule, or the island effect manifestation in a population of the nominative subspecies of the secret toad-headed agama (Phrynocephalus mystaceus mystaceus Pallas, 1776) living on an isolated  sandy massif of Sarykum, Dagestan. Materials on morphometric data, body length and tail length were collected  at two points in the habitat of the nominative subspecies. Data on the Sarykum sand massif were collected in May 2021. At the second point of the range, in the vicinity of  v. Dosang, the Astrakhan region, data were obtained during the spring field seasons of 2010–2014. Our processing of the materials shows that mature individuals of the population on Sarykum are significantly smaller than lizards of the same age group from the Astrakhan region. Our analysis of the published data confirms the smallest possible size of this population of the nominative subspecies. Thus, the population of the secret toad-headed agama on the Sarykum sandy massif may be  a typical example of an island shift, in which large animals tend to become dwarfs, and small ones to become giants,  respectively. In this case, we are dealing with dwarfism of the largest species of  Phrynocephalus genus in the isolated territory of the Sarykum sandy massif. It should be  noted that immature individuals of the populations have no dimensional differences from other populations of th e habitat, which may indicate the physiological dimensional optimum of this age group.
Pengaruh Penggunaan Tepung Tongkol Jagung Terfermentasi Yang Ditambahkan Zn-Biokompleks Pada Kambing Kacang Betina
Authors: Dalle Nautus Stivano , Tukan Hendrikus Demon , Nugraha Elisabeth Yulia , Nguru David Agustinus
Published: March 2024

Penelitian ini bertujuan untuk mengetahui pengaruh suplementasi konsentrat yang mengandung tepung tongkol jagung terfermentasi yang ditambahkan Zn-Biokompleks terhadap respon fisiologis kambing kancang betina. Ternak yang digunakan adalah kambing kacang betina sebanyak 12 ekor pada kisaran umur 6-8 bulan dengan berat badan awal 9,3-13,5kg, rataan 11,20kg dan KV 13,30%. Rancangan yang digunakan adalah Rancangan Acak Lengkap (RAL) dengan 4 perlakuan dan 3 ulangan. Keempat perlakuan tersebut adalah sebagai berikut: R0:Pakan konsentrat tanpa tepung tongkol jagung terfermentasi dan Zn-Biokompleks 2,06g, R1 :Pakan konsentrat yang mengandung TTJF 10% + Zn-Biokompleks 2,06g, R2 :Pakan konsentrat yang mengandung TTJF 20% + Zn-Biokompleks 2,06g, R3:Pakan konsentrat yang mengandung TTJF 30% + Zn-Biokompleks 2,06g. Analisis data menggunakan (ANOVA). Hasil penelitian menunjukkan bahwa denyut nadi R0 (82,37±4.67kali/menit), R1 (84,4±1,50 kali/menit), R2 (86,18±1,25 kali/menit), R3 (89,39±1,89 kali/menit) suhu rektal R0 (25,92±4,670C), R1 (26,09±1,500C), R2 (26,12±1,250C), R3(26,2±1,890C).dan frekuensi pernapasan R0(33,09±4,67 kali/menit), R1(34,3±1,50 kali/menit) R2 (35,2±1,25 kali/menit), R3(35,74±1,89 kali/menit). Hasil penelitian menunjukan bahwa perlakuan berpengaruh tidak nyata (P0,05) terhadap denyut nadi, suhu rektal, frekuensi pernapasan kambing kacang. Kesimpulan dari penelitian ini bahwa suplementasi konsentrat yang mengandung tepung tongkol jagung terfermentasi sampai dengan level 30% ditambahkan Zn-biokompleks memberikan respon yang relatif sama dengan pemberian konsentrat tanpa suplementasi tepung tongkol jagung terfermentasi yang ditambahkan Zn-biokompleks terhadap respon fisiologis ternak kambing kacang.
Hubungan Biaya Operasional, Waktu Kerja dan Lama Usaha Terhadap Income Pedagang Daging Babi di Pasar Tradisional
Authors: Umboh Sintya J. K
Published: March 2024

This study was conducted based on the formulation of the problem that is how much operational costs and profits received by pork retailers and whether there is an effect of operational costs, working hours and length of business on the income of pork retailers in Amurang traditional market. The objectives of the study were (1) to determine the amount of operational costs and revenues received by pork retailers in Amurang traditional market, and (2) to analyze the effect of operational costs, working hours, and length of business on the income of pork retailers in Amurang traditional market. Determination of samples in this study using Purposive Sampling method. Consideration of the determination of the sample in this study is, pork retailers in the city of Amurang who have long been selling pork trading time of at least 3 years and already have a permanent place of sale in the traditional market Amurang, so that the number of respondents sebanhyak 15 people. The results obtained that, the average level of income (profit) Rp. 2.570.500 per day or average income (profit) per month Rp. 83,245,000 with an average weight of 4,050 kilograms of pork per month. Based on the analysis of the correlation coefficient value (r) of 0.95 gives the meaning that, koefisen variables X1 (operating costs), X2 (working hours), and X3 (long business) has a strong relationship (correlation) to the income level of pork retailers by 0.95 the strong relationship with the income level of variables measured can be explained through the coefficient of determination (R) 0.90 means that the income of pork retailers is 90% influenced by variables X1 (operating costs), X2 (working hours) and X3 (long business), while 10% is explained by other variables that are not included in the analysis model. Based on the results of the study concluded that the level of income earned pork retailers in the traditional market Amurang is Rp. 83,245,000 per month with an average weight of the whole piece of pork as much as 4,050 kilograms per month. Operational costs, working hours and length of time simultaneously affect the income of pork retailers in Amurang traditional market. Partially operational costs and length of business affect the income while the variable working hours do not affect the income of pork retailers in Amurang traditional market.
PERILAKU KONSUMEN TERHADAP PEMBELIAN TELUR AYAM RAS DI PASAR TRADISIONAL KOTA MANADO
Authors: Kalangi Lidya S , Kalangi Lidya
Published: March 2024

Commercial chicken eggs are one of the most sought-after livestock products by the community due to their easy availability, affordable price, and complete nutritional content to meet the protein needs of animals. This study was conducted to analyze the characteristics of consumers of commercial chicken eggs and examine the factors influencing consumer behavior towards the purchase of commercial chicken eggs in Manado City. The sample determination method used accidental sampling, which involved randomly selecting respondents who were purchasing commercial chicken eggs at the traditional markets of Bersehati and Pinasungkulan in Manado City. A total of 100 respondents were included in the study. The data analysis utilized multiple linear regression analysis. The results indicated that income, the share of expenditure on purchasing commercial chicken eggs, the number of family members, and the education level of housewives simultaneously influenced the dependent variable, which was the quantity of consumed commercial chicken eggs. The R2 value of 0.545 indicates that changes in the independent variables can explain 54.5% of the changes in the dependent variable, while the remaining 45.5% is attributed to other factors beyond the model equation. The characteristics of consumers of commercial chicken eggs in the traditional markets of Bersehati and Pinasungkulan in Manado City include age, education level, occupation, and income.
Bearing fault detection with application to PHM Data Challenge
Authors: Boškoski Pavle , Urevc Anton
Published: March 2024

Mechanical faults in the items of equipment can result in partial or total breakdown, destruction and even catastrophes. By implementation of an adequate fault detection system the risk of unexpected failures can be reduced. Traditionally, fault detection process is done by comparing the feature sets acquired in the faulty state with the ones acquired in the fault–free state. However, such historical data are rarely available. In such cases, the fault detection process is performed by examining whether a particular pre–modeled fault signature can be matched within the signals acquired from the monitored machine. In this paper we propose a solution to a problem of fault detection without any prior data, presented at PHM’09 Data Challenge. The solution is based on a two step algorithm. The first step, based on the spectral kurtosis method, is used to determine whether a particular experimental run is likely to contain a faulty element. In case of a positive decision, fault isolation procedure is applied as the second step. The fault isolation procedure was based on envelope analysis of band–pass filtered vibration signals. The band–pass filtering of the vibration signals was performed in the frequency band that maximizes the spectral kurtosis. The effectiveness of the proposed approach was evaluated for bearing fault detection, on the vibration data obtained from the PHM’09 Data Challenge.
Comparison of Two Probabilistic Fatigue Damage Assessment Approaches Using Prognostic Performance Metrics
Authors: Guan Xuefei , Liu Yongming , Jha Ratneshwar , Saxena Abhinav , Celaya Jose , Geobel Kai
Published: March 2024

In this paper, two probabilistic prognosis updating schemes are compared. One is based on the classical Bayesian approach and the other is based on newly developed maximum relative entropy (MRE) approach. The algorithm performance of the two models is evaluated using a set of recently developed prognostics-based metrics. Various uncertainties from measurements, modeling, and parameter estimations are integrated into the prognosis framework as random input variables for fatigue damage of materials. Measures of response variables are then used to update the statistical distributions of random variables and the prognosis results are updated using posterior distributions. Markov Chain Monte Carlo (MCMC) technique is employed to provide the posterior samples for model updating in the framework. Experimental data are used to demonstrate the operation of the proposed probabilistic prognosis methodology. A set of prognostics-based metrics are employed to quantitatively evaluate the prognosis performance and compare the proposed entropy method with the classical Bayesian updating algorithm. In particular, model accuracy, precision, robustness and convergence are rigorously evaluated in addition to the qualitative visual comparison. Following this, potential development and improvement for the prognostics-based metrics are discussed in detail.
Applying Weibull Distribution and Discriminant Function Techniques to Predict Damaged Cup Anemometers in the 2011 PHM Competition
Authors: Cassity Joshua , Aven Christopher , Parker Danny
Published: March 2024

Cup anemometers are frequently employed in the wind power industry for wind resource assessment at prospective wind farm sites. In this paper, we demonstrate a method for identifying faulty three cup anemometers. This method is applicable to cases where data is available from two or more anemometers at equal height and cases where data is available from anemometers at different heights. It is based on examining the Weibull parameters of the distribution generated from the difference between the anemometer’s reported measurements and utilizing a discriminant function technique to separate out the data corresponding to bad cup anemometers. For anemometers at different heights, only data from the same height pair combinations are compared. In addition, various preprocessing techniques are discussed to improve performance of the algorithm. These include removing data that corresponds to poor wind directions for comparing the anemometers and removing data that corresponds to frozen anemometers. These methods are employed on the data from the PHM 2011 Data Competition with results presented.
Feature Extraction and Pattern Identification for Anemometer Condition Diagnosis
Authors: Sun Longji , Chen Chao , Cheng Qi
Published: March 2024

Cup anemometers are commonly used for wind speed measurement in the wind industry. Anemometer malfunctions lead to excessive errors in measurement and directly influencethe wind energy development for a proposed wind farm site. In the PHM 2011 Data Challenge Competition, two types of data need to be processed for anemometer condition diagnosis: paired data consisting of wind data from paired anemometers, and shear data composed of measurements from an array of anemometers at different heights. Since the accuracy of anemometers can be severely affected by the environmental factors such as icing and the tubular tower itself, in order to distinguish the cause due to anemometer failures from these factors, our methodologies start with eliminating irregular data (outliers) under the influence of environmental factors. For paired data, the relation between the normalized wind speed difference and the wind direction is extracted as an important feature to reflect normal or abnormal behaviors of paired anemometers. Decisions regarding the condition of paired anemometers are made by comparing the features extracted from training and test data. For shear data, a power law model is fitted using the preprocessed and normalized data, and the sum of the squared residuals (SSR) is used to measure the health of an array of anemometers. Decisions are made by comparing the SSRs of training and test data. The performance of our proposed methods is evaluated through the competition website. As a final result, our team ranked the second place overall in both student and professional categories in this competition.
TrajecNets: Online Failure Evolution Analysis in 2D Space
Authors: Shahid Nauman , Ghosh Anarta
Published: March 2024

We propose a novel Recurrent Neural Network (RNN) based autoencoder for embedding the run-to-failure time series sensor data in a 2D feature space. The embedding, extracted from the network, is in the form of a smooth trajectory, which represents the temporal evolution of data from healthy to failure states, hence the name TrajecNets. The visualizable 2D trajectory can be used directly for highly intuitive and interpretable health monitoring, which can in turn be used for Remaining Useful Life (RUL) estimation task, without compromising the performance. We also propose a novel unsupervised failure prediction methodology which uses the 2D trajectories and health curve of the time series to compute evolving failure mode probabilities. Together, the visualizable 2D trajectories and the interpretable failure mode probabilities, health curve and RUL are envisaged to provide system and maintenance engineers, insight into failure dynamics. Experiments on NASA CMAPSS Turbofan benchmark dataset showpromising results on degradation tracking, health monitoring, failure prediction and RUL estimation tasks.
Towards Developing a Novel Framework for Practical PHM: a Sequential Decision Problem solved by Reinforcement Learning and Artificial Neural Networks
Authors: Bellani Luca , Compare Michele , Baraldi Piero , Zio Enrico
Published: March 2024

The heart of prognostics and health management (PHM) is to predict the equipment degradation evolution and, thus, its Remaining Useful Life (RUL). These predictions drive the decisions on the equipment Operation and Maintenance (O&M), and these in turn influence the equipment degradation evolution itself. In this paper, we propose a novel PHM framework based on Sequential Decision Problem (SDP), Artificial Neural Networks (ANNs) and Reinforcement Learning (RL), which allows properly considering this feedback loop for optimal sequential O&M decision making. The framework is applied to a scaled-down case study concerning a real mechanical equipment equipped with PHM capabilities. A comparison of the proposed framework with traditional PHM is performed.
Prognostics and Health Management for Rechargeable Batteries
Authors: Tsui Kwok L
Published: March 2024

After numerous successful applications of statistical quality control and reliability methods in manufacturing industries in the past several decades, the quality paradigm has shifted from manufacturing application to field operation in many industries. This shift was triggered by continuous concerns in product reliability, system safety, and failure prevention, and made possible by latest advancement in data collection technologies and development of powerful modelling algorithms. This general field of research provides tremendous opportunities for interdisciplinary research and has been classified as prognostics and system health management (PHM). In this talk we will share our experience of PHM research in the application of rechargeable batteries through methods in data mining, diagnostics and prognostics, anomaly detection and monitoring.
Systems Engineering Approach to PHM in Aerospace
Authors: Doughty Kurt James
Published: March 2024

Systems engineering approaches to PHM are established by first capturing the right data. Understanding prominent component failure modes and their system level effects allows engineers to target necessary sensing feedback to enable precise prognostics algorithm development. For many commercial aircraft, however, requirements for PHM are either not identified or not prioritizedin advance of entry into service (EIS). As the design of aircraft systems evolve, adding sensors is essential to comply with baseline performance requirements, such as robust operation throughout the design envelope, fault detection via built-in test (BIT), and safety via backup and protective controls. Conversely, weight reduction efforts during aircraft systems design often result in leansensor architectures. Incorporating PHM requirements early in the aircraft design process will enable more robust sensor architectures and enhance PHM capabilities.This presentation will review design considerations for commercial aircraft systems as they relate to PHM; including sensor provisioning and BIT functionality. Examples of prognostics algorithm development for legacy system architectures will be discussed. The future of designing aircraft systems for PHM will also be explored.
Using physical based models for machinery RUL estimation
Authors: Bortman Jacob , Klein Renata
Published: March 2024

Machinery prognosis is the process of forecasting the remaining operational life (RUL), future condition, or probability of failure based on the acquired condition monitoring data. RUL forecast becomes crucial since it allows planning of efficient maintenance actions. In order to estimate the remaining usefull life it is needed, first, to estimate the damage severity or size, and then, to forecast the damage growth model. Damage size estimation is not yet developed and needs additional research. Classic theories assume that energy dissipation is proportional to fault size. For small faults, it is not correct. In general the energy-fault size relation depends on the transmission path from the defect to the snsor which differs for every case of defect location, machine and sensor. Therefore the estimation of the fault size is crucial. State of the art algorithm for bearings size estimation will be presented. The algorithm approach is based on insights from a general dynamic bearing model and an analytical model for RE-spall interaction. The outline of these models will be presented. Other machine components such as, gears and shafts will be discussed. In the second stage, understanding of the damage progression process is needed. This stage is essential for estimation the RUL. The required steps towards damage progression tools will be discussed. The models allow to examine the the algorithms sensitivity to different types of faults, geometric errors, misalignment, unbalance, system parameters etc.
Recent Advances at KAIST in In-process NDE and Smart Hangar for Aerospace SHM
Authors: Lee Jung-Ryul
Published: March 2024

Recently, we are in transition from metallic to composite in operation and manufacturing of aerospace structures. NDE, SHM, and PHM are all over used, in design, manufacturing, operation and overhaul stages in their life. In this invited talk, opto-electronic systems capable of in-process NDE, in-situ NDE and integrated SHM and their real world applications are introduced. In addition, their field implementation scenario are proposed and advances in Smart Hangar are introduced.
Metamaterial-based Enhancement of Elastic Wave Energy Harvesting
Authors: Kim Miso , Park Choon-su , Choi Wonjae , Shin Yong Chang , Jo Soo-Ho , Yoon Heonjun , Kim Byeng D. Youn iso
Published: March 2024

Enhancement of metamaterial-based energy harvesting will be presented from design, analysis towards experimental demonstration. Metamaterials, artificially engineered materials, exhibit unique properties including bandgap  and negative refractive index and thus enable us to manipulate mechanical wave propagations. In order to amplify input mechanical wave energy into energy harvesting systems, metamaterials can be utilized to guide and localize acoustic and elastic waves towards the desired position for harvesting. Recently, several research efforts on metamaterial-based enhancement of energy harvesting have been reported, but mostly based on intuitive design or with little experimental support. We propose several metamaterial-based energy harvesting systems including phononic crystals with defect and acoustic metamaterials with local resonances. Systematic design through geometric and bandgap optimization process is performed and followed by experimental demonstration. Drastic enhancement of energy harvesting performance via metamaterials is demonstrated and thoroughly investigated both analytically and experimentally.
PHM Frontiers: Physics-based Approach to Deep Learning
Authors: Jung Joon Ha , Kim Myungyon , Ko Jin Uk , Youn Byeng D.
Published: March 2024

Journal bearing rotor systems are widely used in various industrial applications. Due to uncertainties, the rotor may not behave as it is expected, and thus accidents may happen, which causes economic losses. To prevent such incidents, diagnosing the health state of rotor systems is of critical importance. Conventional health diagnosis approaches heavily rely on the physical features of the rotor systems, which require large amount of resources to develop. To minimize the amount of time and effort required for the feature engineering process of the rotor systems, the deep learning based feature engineering method is proposed in this paper.Among various deep learning techniques, convolutional neural networks (CNN), which is known to be powerful in recognizing images, is used. To use CNN, vibration signals are transformed into images using the omnidirectional regeneration (ODR) method. The ODR method can generate virtual vibration signals in any direction from the actual vibration signals acquired from the two orthogonally placed proximity sensors. Then, the virtual ODR signals are transformed into images that sketch vibration signals acquired at all directions. Lastly, the image patterns are recognized by CNN, which replaces the expensive feature engineering step used in the conventional methods. The proposed deep learning based feature engineering is validated with the datasets from the journal bearing rotor test-bed. It is demonstrated that the deep learning based anomaly detection of the journal bearings can substantially improve the efficiency and accuracy, compared to the conventional anomaly detection methods.
Development of User Customized non-contact Platform based on Mini PC and Short-range Wireless Data Communication Sensor
Authors: Kim Jung Woo , Lee Eun Ji , JIN WANSHI , Choi Jae Boong
Published: March 2024

Due to a rapid growth of smart phone market, the development of a new network and the expansion of internet communication and platform technology make a huge amount of information exchange possible in real time. Asmart phone market has transformed into a user-centered market, satisfying the user’s requirements. The convergence of smart device and the IoT (Internet of Things) technology are underway using big data. This paper introduces the development of user customized non-contact platform connecting a mini PC and a short-range wireless data communication sensor. We verified the possibility of application of this platform in the household electric appliances.
Experimental study of the vibration fatigue for beam with hard coating damping treatment
Authors: Zhai Jing-yu , Chen Hui , Chen Yu-gang , Han Qing-kai
Published: March 2024

The hard coating material, with its superior advantages to temperature and corrosion resistance, is an ideal material for controlling the vibration of structures duo to its high capacity to dissipate vibration energy. The hard coatingmaterial has been widely used in the aerospace field. In this paper, the vibration fatigue properties of beam with hard coating damping treatment are investigated further. An experiment is conducted to obtain the vibration fatigue mechanism of the hard coating beam, in which the vibration fatigue life of beam are measured under bending and local resonance condition. The vibration excitation is produced by the shaker driven by an amplified signal from vibration controller. Moreover, based on the finite element fatigue analysis software ANSYS nCode Designlife, the vibration fatigue simulation analysis is carried out, and the influence of the vibration frequency, amplitude and various damping properties for the vibration fatigue life are all considered and compared. The results indicate that an appropriate selection hard coating parameters can obtain desirable damping properties and can improve the vibration fatigue life.
Rub-impact and Misalignment induced Vibration of HP Rotor System in Aero-Engine
Authors: Han Qingkai , Ma Pingping , Zhang Hao , Zhai Jingyu
Published: March 2024

The numerical simulations of vibration induced by rubimpact and misalignment happening on the high pressure (HP) rotor system of an aero-engine are achieved, and also confirmed by experimental measurements on a specialdesigned test-rig. The simulation model of the rotor dynamics is set up by using of ADAMS, composes of both effective stiffness elements of two different elastic supporting and s rigid shaft. The local rub-impact happening between one disc and the casing shell, the front supporting misalignment are involved in the model. In the model, the rub-impact mechanism is expressed by the parameters of its stiffness and damping and friction, and the misalignment is simulated by changing the position of the front supporting. To change the running speed and the rub-impact or misalignment levels, the transverse vibrations of the discs and shaft of the HP rotor are calculated. The numerically simulated time-domain responses, the frequency spectra and the shaft-center trajectories are plotted and compared on the above different operating conditions. These simulation results are compared to explore the efforts on rotor vibrations of the rotating speed, rubbing stiffness or friction, and the misalignment displacement or angle. Finally, the simulation results are also consistent with the measured vibrations on the HP rotor test-rig, which confirms that the established model and simulation method and typical results are acceptable.
A Study on Reliability Assessment Criteria of Diaphragm-type Accumulator for Intake and Exhaust Valve of Large Ship
Authors: Kim Tae-Seok , Lee Jong-Jik , Lee Yong-Bum , Choi Byung-Oh , Yoo Han-Ju
Published: March 2024

A diaphragm type accumulator ("accumulator") is used in a wide range of hydraulic systems, especially the intake valve for fuel injection and the exhaust valve activated after a stroke in the electronic control unit of a ship to reduce shock waves and pulsation pressure and compensate for pressure. In this application, the diaphragm operates in the same manner as in the engine operation mode (240 rev/min : 4 Hz) and is exposed to harsh conditions including abrupt surge pressure (ΔP). Given these such conditions, the diaphragm is physically and structurally vulnerable to recurring faults. While existing local and international assessment standards largely attribute faults in accumulators to damaged diaphragms, screws in the caps and body assemblies break due to structural problems. This leads to loss of functionality and safety issues instead of decreasing performance. This study assumes that the main cause of faults in diaphragm type accumulators are damaged screws and explores the method of assessing reliability using pressure rating testing on a pressurized vessel of NFPA T/2.6.1 dimension. It also looks into a monitoring system to identify any N2 gas leakage during testing.
Experimental study on torsional load of grid coupling
Authors: Jung Dong Soo , Kim Jong Cheol , Jung Han Young , Lee Seung Yong
Published: March 2024

The coupling connects the drive shaft and the driven shaft, and the shaft is used in the industrial field by the power transmission device. The main functions of the coupling are largely divided into the function of transmitting the power and the function of protecting the mechanical system when the coupling member of the coupling is destroyed when an overload occurs between the driving shaft and the driven shaft. Grid coupling, which is one of the mechanical power transmission parts, is composed of hub, grid, seal, cover, etc. and has the characteristic of transmitting power at high speed and high torque. In general use conditions, elasticity of the grid has flexibility to twist generated in misalignment state such as impact load, axis error, parallel error, angular error caused in normal rotation or reverse rotation, and to reduce vibration and impact load to be. In addition, when the overload occurs, the grid is cut off and the transmission power is cut off to protect the equipment connected to the driving shaft and the driven shaft.
New Approach for Fault Identification using Residual-based Fault Diagnosis
Authors: Jeong Haedong , Park Bumsoo , Park Seungtae , Min Hyungcheol , Lee Seungchul
Published: March 2024

Manufacturing machinery is becoming more complicated, and breakdowns of machinery are related to not only efficiency reduction, but also safety issues. Due to the needs for maintaining high reliability within facility operation, various methods for condition monitoring are suggested as the importance of maintenance has increased. Among the various prognostics and health management (PHM) techniques, in this paper, a model-based fault detection and isolation (FDI) technique for the diagnosis of the machine health condition is introduced. In particular, we suggest a new approach for the fault identification that extracts the information of the fault signal such as the magnitude or shape of the fault. The main idea of this methodology is in defining the relation between a fault signal and observer theory. For the proposed method, a numerical simulation is conducted to show the effectiveness of the fault detection and identification under various situations. Then a comparison between the proposed method and data-driven methods is conducted to show the difference in aspect for fault diagnosis.