bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Analyzing of Pisa-based Mathematics Problem Solving Ability based on the Algebra Learning Object
Authors: Sumardi  , Herawanto Muhammad Risal 
Published: February 2021

Abstract
The aim of this study was describing the ability in solving math problems based on PISA change and relationship content based on algebra learning objects. This research was descriptive qualitative study involving 28 students of VIII B class at SMP Negeri 25 Surakarta. The techniques of collecting data used tests and interview, while the techniques of analyzing data were using data reduction, presentation, and drawing conclusions. The results of this study was the students’ problem solving abilities based on four algebra learning objects according to Skemp’s view, namely: 1) using symbols, 2) mathematical models, 3) linear equations and their solutions, and 4) algebraic calculations. The students with high-level math abilities were able to apply four algebra learning objects, namely: using symbols, making mathematical models, linear equations and solving them well, and the calculations correctly. The student’s weaknesses was not accurate in writing on the result of the unit obtained and there were no several symbols in giving information. The students with mid-level math abilities were only able to use symbols and create math models, the writing of the linear equations was correct but the solution was still incorrect because it was like Polya’s stage, so it was not quite right because there are no calculation steps. The students with low-level math abilities were only correct in writing linear equations, the way of solving and calculating the problems were still incorrect, and the writing of mathematical models and using symbols were incorrect.
The development of student worksheets based on higher order thinking skill for mathematics learning in junior high school
Authors: Sutama  , Prayitno Harun Joko , Narimo Sabar , Ishartono Naufal , Sari Diana Purwita 
Published: February 2021

Abstract
There are three purposes of this study. 1) to develop student worksheets based on Higher Order Thinking Skills (HOTS); 2) to test the feasibility of developed student worksheets, and 3) to analyse student assessments of developed worksheets. This research is a research and development (R&D). The development model is ADDIE which consists of 5 stages, namely Analysis, Design, Development, Implementation, and Evaluation. The study was conducted at SMP Negeri 1 Karanganyar in the academic year of 2018/2019. Data collection was obtained through observation, interviews, documentation, and questionnaires. Data analysis techniques used was critical analysis and comparative descriptive analysis. The results of the research were 1) This research and development had produced a worksheet based on HOTS on the subject of algebra; 2) Student worksheets developed were declared valid by experts and education practitioners, and 3) The results of the students’ responses showed that the student worksheets that had been developed were interesting and the questions of HOTS presented were quite challenging to solve. Thus, students’ worksheets based on developed HOTS were suitable to be used in mathematics learning.
Ethnomathematics Vs Ethomodeling: how does cigugur traditional community determines the direction of the wind to seek fortune based on month
Authors: Umbara Uba , Wahyudin  , Prabawanto Sufyani 
Published: February 2021

Abstract
This study discusses the way of Cigugur indigenous communityin predicting the direction ins seeking fortunes. It uses a phenomenological approach with a realist ethnographic design through observation techniques, in-depth interviews, documentation, and field notes. The findings of this study indicate that the system of knowledge and livelihood which are included in the universal element of culture are implemented by the community using formal mathematical principles. Ethnomathematics as a research genre tries to reveal the dimensions of basic universal mathematical activities, while ethnomodeling as a methodology is used to represent the ideas and practices of community mathematics into academic mathematics through ethical, emic and dialctical approaches. The combination of naktu weton lahir, naktu pasaran, naktu tahun and naktu bulan, the time of one’s birth month can be used to predict a good direction in seeking fortune. Based on the study of ethnomathematics, the community determines the direction in seeking fortune, the mathematical concept used by the traditional Cigugur community is the concept of sequential pairs, relations, summations, and comparisons. Meanwhile, based on ethnomodeling, the community uses the concept of modulo and congruence. Ethnomatematics and ethnomodeling provide a different perspective on the conceptual mathematics that is inherent with the universal element of holistic culture.
Reflective thinking process of students in completing mathematical problems based on mathematical reasoning ability
Authors: Tisngati Urip , Genarsih Tunjung 
Published: February 2021

Abstract
This research aimed to describe the reflective thinking process of eighth-grade students of junior high schools in solving mathematical problems of circle material based on mathematical reasoning. It was a qualitative descriptive with a case study approach. There were 6 subjects selected by using purposive sampling technique based on mathematical reasoning levels. The methods used were test, interviews, and documentation techniques. The results showed that students with high mathematical reasoning level were able to fulfill all indicators of the reflective thinking process including identifying facts and questions, explaining the operations to be chosen, carrying out plans, and giving logical conclusions with indicators students wrote the correct final answers based on the order of the previous problem solving process; students with medium mathematical reasoning fulfilled two to three indicators of identifying facts and questions, explaining the operations to be chosen, carrying out a problem-solving plan; students with low mathematical reasoning fulfilled an indicator of identifying facts and questions; students tend to experience errors in the calculation aspects, lack of students’ prior knowledge, understanding, and mathematical attitude. It was concluded that there is a connection between problem solving and mathematical reasoning with reflective thinking ability of students. It have implications for teachers to condition mathematics learning by paying attention to students’ thinking skills.
Unsupervised Learning for MRI Brain Tumor Segmentation with Spatially Variant Finite Mixture Model in Reversible Jump MCMC Algorithm
Authors: Pravitasari Anindya Apriliyanti , Iriawan N , Fithriasari K , Purnami S W , Irhamah  , Ferriastuti W 
Published: February 2021

Abstract
MRI brain tumor segmentation is an important topic in medical image processing. Manual segmentation is risky and time-consuming when the MRI is in low quality. The automatic segmentation can be a solution to manage this problem. This paper proposed an improved modeling approach for unsupervised learning trough Spatially Variant Finite Mixture Model (SVFMM). The main contribution is the automation of the SVFMM algorithm to find the optimum number of clusters. This is achieved by employing the birth-death random process in Bayesian Reversible Jump MCMC. Validation of the proposed model is done by calculating the Correct Classification Ration (CCR) in comparison to the original SVFMM and Gaussian Mixture Model (GMM). The proposed model provides similar performance in image segmentation compared to the original SVFMM but is better than GMM. However, SVFMM-RJMCMC is faster and more efficient in finding the optimum number of clusters.
The Method to Analyse the Association between Objects and Variables in the Form of / x 2 Contingency Tables with Continuous Variables Additional Data
Authors: Ginanjar Irlandia , Sunengsih N , Sudartianto  
Published: February 2021

Abstract
If the row and column categories of a contingency table sequentially seen, as objects and variables, then they are object data with discrete variables. Often from objects obtained additional data in the form of continuous variables. Based on these discrete and continuous variables, the more accurate method is necessary to analyse the associations between these variables. Treating discrete data as continuous is wrong, so this article aims to analyse the association of data in the form of / x 2 contingency tables with additional data that is continuous. From the data in the form of / x 2 contingency table, it converted using the simplification of correspondence analysis (SoCA), so that continuous principal coordinates obtained. Furthermore, the association between continuous variables was analysed using the cosine value of the angle between the two vectors. Case studies use poverty data in Indonesia, which published by the Central Statistics Agency (BPS-Statistics Indonesia). Data in the form of contingency tables are people population lived in poverty based on province and area of residence (urban or rural). Additional variables are poverty depth index, severity index, Gini ratio, food poverty line and non-food poverty line. The results of the analysis obtained information that in urban areas tend to have high Gini ratio, food poverty lines and non-food poverty lines, for rural areas tend to have a high poverty depth and severity index.
The Effect of Regional Characteristics and Relationship Among Locations In Air Pollution Using Spatial Autoregressive (SAR) and Spatial Durbin Models (SDM)
Authors: Suryowati Kris , Bekti RD , Fajiriyah R , Siswoyo E 
Published: February 2021

Abstract
Bantul Regency in Special Region of Yogyakarta, which consists of 17 sub-districts, is an area that continues to grow and has increased population activities. In 2014, 16 sub-districts had been contaminated by air quality. To find out things that can affect air pollution in the area, this study conduct spatial model. This method is used as an alternative of OLS a method that does not meet assumptions when used in the case of spatial data. The reason for using spatial model is because there is an autocorrelation in air quality among sub-districts. By OLS regression model, a significant factor influencing is the number of villages according to the type of transportation infrastructure. However, this model does not pay attention to the geographical location factor and the residual assumption that normal distribution is not met. The results of spatial model is Spatial Durbin Model (SDM) have a good performance because have a small AIC than SAR. In SDM, the variables that significant effect on air pollution were population density, transportation infrastructure, lag of population density, lag of transportation infrastructure, and lag of air pollution. Sub district will have high of air pollutan if have high of population density and transportation infrastructure, also close to other sub districts which also have high population density and transportation infrastructure.
Dynamical Analysis on A Model of Cholera Epidemic with Quarantine, Vaccination, and Two Path of Transmissions
Authors: Suryani Lilis , Kusumawinahyu W. M. , Shofianah N. 
Published: February 2021

Abstract
This research focus on dynamical analysis of a SIQRVB (Susceptible-Infectious-Quarantined-Recovered-Vaccinated-Bacterial) model. It describe the spread of cholerae with quarantine, vaccination and two transmission paths. As is well-known, there mainly exist two transmission paths for cholerae: environment-to-human transmission and human-to-human transmission. This model has two equilibrium points, that is disease-free equilibrium point which always exists and an endemic equilibrium point that exists with some conditions. The local stability of the equilibrium points is investigated by using Routh-Hurwitz criteria. The method of Next Generation Matrix is applied to get the basic reproduction number R0
. It can be shown numerically that disease-free equilibrium point is locally asymptotic stable when R0 < 1, while the endemic equilibrium point exist and locally asymptotic stable when satisfy Routh-Hurwitz criteria. Numerical simulations are given to illustrate the theoretical results.
Fuzzy c-shells for clustering of data’s LQ45 in Indonesia based on earnings per share and price earning ratio
Authors: Pratiwi Nafisa Berliana Indah , Saputro D R S , Widyaningsih P 
Published: February 2021

Abstract
Stocks are financial assets which is procurement valuable document of an enterprise that exhibit the ownership. Bursa Efek Indonesia (BEI) has stock index mentioned as Liquid 45 (LQ45). LQ45 includes 45 enterprises with high fundamentals. Stock investors shall use the finance report as primary decision in stocks investment. Profitability ratios is finance ratio component to evaluate the sale, assets, and stocks value. Earnings Per Share (EPS) measures investor perspective in form of returns calculation that will be obtained in certain period. Price earning ratio (PER) describes amount have to be paid by the investor for the profit of the enterprise. Stocks clustering is a necessary decision to gain maximal profits. Stocks clustering determined by clustering algorithm and stocks budge unpredictably then solved by fuzzy concept. The clustering for LQ45 solved by fuzzy c-shells clustering (FCS). FCS clustering for LQ45 results three clusters. First cluster has 7 enterprises with radius of cluster is 1.77, second cluster has 27 enterprises with radius of cluster is 0.37, and the third cluster has 11 enterprises with radius of cluster is 1.55. Xie Beni validity index value 0.4269798. That most minimum Xie Beni value results optimum and valid clusters.
Analysis of The Efficiency SA (Simulated Annealing) Model And Fuzzy Time Series (Case Study: Inventory System PT Y)
Authors: Ariyanto Riki , Heru Tjahjana R , Udjiani Titi 
Published: February 2021

Abstract
Forecasting sales and minimizing storage costs is the company’s strategy to maximize inventory in anticipation of sales spikes in stores so that it can be fulfilled even though storage warehouses are limited, on the other hand there is competition among distributors in ordering goods, which is trying to get the maximum level of service from suppliers so warehouse needs can be fullfiled. By using the forecasting method, Chen Fuzzy Time Series to predict future sales combined with the simulation annealing method (simulated annealing algorithm) as an optimization method in order to obtain the lowest possible storage costs. This combination of methods can improve shipping services from warehouse to store as a result of loss sales cause inventory shortages can be controlled so that inventory costs are more minimal and warehouse storage of goods can be maximized, the combination of these methods is more effective than conventional methods available at PT Y
Multi responses taguchi optimization using overlaid contour plot and desirability function
Authors: Winarni Sri , Sunengsih N , Ginanjar I 
Published: February 2021

Abstract
Optimization is the process of getting an optimal response. The taguchi design is an experimental design that is often used to get robust responses. In the multi-response Taguchi design, the optimization process is carried out by considering all responses simultaneously. Cases study used in this research is aluminum production cases with four treatments, namely tool rotational speed, welding speed, shoulder tool diameter and pin diameter. Each treatment was tried with three levels. Optimized responses are tensile strength, average microhardness and average grain size.The purpose of this research is determining the point of optimization using response surface method and desirability function. The optimization results obtained are tool rotational speed of 1100 RPM, Welding speed of 40 mm/min, Shoulder diameter of 21 mm, and pin diameter of 5.4 mm.
A Fixed Effect Panel Spatial Error Model in Identifying Factors of Poverty in West Java Province
Authors: Sudartianto  , Firman  , Suparman Y. , Ginanjar I. 
Published: February 2021

Abstract
In the last five years, poverty had been a major problem in West Java Province (WJP). Hence, it becomes a strategic development issue for the next five years. To contribute in eradicating the poverty, we aimed this study at identifying poverty factors and measuring their effects. There are two issues in modelling poverty in WJP. First, there was spatial dependency in poverty among regions. Second, due to data limitation, some important factors were not included in the empirical model. Both might lead to bias in regression parameter estimates. Accordingly, we applied a fixed effect panel spatial error model on the poverty rate in WJP. We found that health and economic welfare effected poverty.
Multiple Correspondence Analysis for Identifying the Contribution of Infant Mortality Indicator Categories
Authors: Purwandari Titi , Ginanjar Irlandia , Dewi Dhita Diana 
Published: February 2021

Abstract
Infant mortality rate is one of several other indicators that are very susceptible in order to illustrate the mark of public health problems. This indicator is substantial to know the cause of the deaths as well as how success the maternal and child health program. This study aims to determine the characteristics of the causes of infant deaths based on age groups and sub-districts in the city of Bandung using multiple correspondence analysis. The results of the study concluded that asphyxia, early neonatal age groups provide significant positive dependence on the sub-district of Bojongloa Kaler, Bojongloa Kidul, Cicendo, Cidadap, Lengkong. Asphyxia, infant age groups provide significant positive dependence on sub-district of Cibeunying Kidul, Cinambo, Kiara Condong. Low birth weight, early neonatal age groups provide significant positive dependence on sub-district of Andir, Rancasari. Congenital abnormalities, early neonatal age groups provide significant positive dependence on sub-district of Babakan Ciparay, Batununggal, Sukajadi. Congenital abnormalities, advanced neonatal age groups provide significant positive dependence on sub-district of Bandung Kidul. Congenital abnormalities and infant age groups provide a significant positive dependence on sub-district of Coblong. Pneumonia, the early neonatal age group provide a significant positive dependence on the sub-district of Bandung Kulon. Sepsis, infant age groups provide significant positive dependence on sub-district of Bandung Wetan.
Uncertainty in different precipitation products in the case of two atmospheric river events
Authors: Ramos Alexandre M , Roca Rémy , Soares Pedro M M , Wilson Anna M , Trigo Ricardo M , Ralph F Martin 
Published: February 2021

AbstractOne of the World Climate Research Programme Grand Challenges is to evaluate whether existing observations are enough to underpin the assessment of weather and climate extremes. In this study, we focus on extreme associated with atmospheric rivers (ARs). ARs are characterized by intense moisture transport usually from the tropics to the extra-tropics. They can either be beneficial, providing critical water supply, or hazardous, when excessive precipitation accumulation leads to floods. Here, we examine the uncertainty in gridded precipitation products included in the Frequent Rainfall Observations on GridS (FROGS) database during two atmospheric river events in distinct Mediterranean climates: one in California, USA, and another in Portugal. FROGS is composed of gridded daily-precipitation products on a common 1° × 1° grid to facilitate intercomparison and assessment exercises. The database includes satellite, ground-based and reanalysis (RE) products. Results show that the precipitation products based on satellite data, individually or combined with other products, perform least well in capturing daily precipitation totals over land during both cases studied here. The RE and the gauge-based products show the best agreement with local ground stations. As expected, there is an overall underestimation of precipitation by the different products. For the Portuguese AR, the multi-product ensembles reveal mean absolute percentage errors between −25% and −60%. For the western US case, the range is from −60% to −100%.
Do climate teleconnections modulate wildfire-prone conditions over the Iberian Peninsula?
Authors: Rodrigues Marcos , Peña-Angulo Dhais , Russo Ana , Zúñiga-Antón María , Cardil Adrián 
Published: February 2021

Abstract
Climate teleconnections (CT) synchronize and influence weather features such as temperature, precipitation and, subsequently, drought and fuel moisture in many regions across the globe. CTs thus may be related to cycles in wildfire activity, and thereby help fire managers to anticipate fire-prone weather conditions as well as envisaging their future evolution. A wide number of CTs modulate weather in the Iberian Peninsula (IP), exerting different levels of influence at different spatial and seasonal scales on a wide range of weather factors. In this work, we investigated the link between the most relevant CT patterns in the IP and fire activity and danger, exploring different spatial and temporal scales of aggregation. We analyzed a period of 36 years (1980–2015) using historical records of fire events (>100 ha burned) and the Canadian Fire Weather Index (FWI). Cross-correlation analysis was performed on monthly time series of CTs and fire data. Results pointed towards the North Atlantic Oscillation (in the western half of the IP) and Mediterranean Oscillation Index (along the Mediterranean coast) as the key CTs boosting burned area (BA) and fire weather danger in the IP. Both CTs relate to the relative position of the Azorean anticlone, fostering hazardous fire weather conditions during their positive phases, i.e. low rainfall and warm temperature leading to low fuel moisture content. The Scandinavian pattern index also played an important role in the western half of the Peninsula, linked to a decrease in rainfall during its negative phases. Nonetheless, the association between the CTs and BA (up to 0.5 Pearson’s R p < 0.05) was weaker than the observed between CTs and FWI (up to 0.75 Pearson’s R p < 0.05).
Robust fraudulence detection of patchouli oil plant using near infrared spectroscopy
Authors: Meilina H , Munawar A A 
Published: February 2021

Abstract
This study aimed to apply the near infrared reflectance spectroscopy (NIRS) for a robust and fast detection method for fraudulence in patchouli oil plant. Pure patchouli oil sample and adulterated patchouli oil with ethanol were used as samples in this work. Spectral data in form of transmittance were acquired in wavenumbers range from 400 to 4000 cm−1. A total of 60 patchouli oil were adulterated and mixed using six difference concentration of ethanol while 10 remaining patchouli oil samples were pure without mixed with other substances. Classification models of pure and adulterated patchouli oil samples were established using principal component analysis followed by cross validation approach. The results showed that the models can distinguish between pure and mixed patchouli oil with 100% accuracy with two principal components (PCs) of the PCA. Based on obtained results, it may conclude that NIRS approach can be used to determine and classify patchouli oil samples based on their purity and fraudulence with ethanol