Confidence interval estimation of gamma distribution lifetime data using score and bootstrap methods

Confidence interval estimation of parameters determines the value interval, which is calculated based on statistical measurements and has specific estimates probability that contains the actual parameters. A method is needed to estimate the parameters' confidence interval, and the methods used are the Score method and the Bootstrap method. This study aims to estimate parameters by using the maximum likelihood estimation method and analyze the reliability of the aircraft engine cooling system's lifetime that follows the Gamma Distribution, and estimate the confidence interval of the parameters.

El nino index prediction model using quantile mapping approach on sea surface temperature data

El Nino is a global climate phenomenon caused by the warming of sea surface temperatures in the eastern Pacific Ocean. El Nino has a powerful effect on the intensity of rainfall in several areas in Indonesia. El Nino impacts can be minimized by predicting the El Nino index from the sea surface temperature in the Nino 3.4 area. Therefore, many researchers have tried to predict sea surface temperature, and many prediction data are available, one of which is ECMWF. But, in reality, the ECMWF data still contains systematic errors or bias towards the observations. Consequently, El Nino predictions using ECMWF data are less accurate. For that reason, this study aims to correct the ECMWF data in the Nino 3.4 area using statistical bias correction with a quantile mapping approach. This method uses ECMWF data from 1983-2012 as training data and 2013-2018 as testing data. For this case, the results showed that 60% of El Nino's predictions on the testing data had improved the mean value. Also, all of El Nino's predictions on the testing data have improved the standard deviation value. Moreover, data testing's expected error can be corrected for all months in the 1st to 4th lead times. But, in the 5th to 7th lead times, only November-June can be corrected.

The development of student activity sheet on trigonometric material based on local culture

Mathematics and culture are two different things, but they have a very close relationship in everyday life included in learning activities. Therefore, this research aims to describes the process and results of developing student activity sheets based on local culture on Simple Trigonometric Function Graphs. This research type is research and development. The product developed in this research is a student activity sheet based on local culture on Simple Trigonometric Function Graphics. Student activity sheets are developed based on a modified 4-D development model, which consists of defining, designing, and developing. At the definition stage; conducted a preliminary analysis, student analysis, material analysis, task analysis and specification of learning objectives. At the design stage; The preparation of student activity sheets based on local culture is carried out, selecting the format and then doing the initial design. At the development stage; The design results are validated by the expert and then revised according to the expert's notes. From the results of the research and data analysis conducted by researchers, it was found that the student activity sheets developed had met the criteria for good learning tools because they were declared valid, practical and effective.

Integer linear programming application in production results optimization using cutting plane method

Integer Linear Programming is a special form of linear programming which the decision variables are in integer form. Berkah Rasa is a home industry business in the form of Jenang Ayu and Jenang Krasikan processed food. The daily production that carried out by Berkah Rasa is based on the availability of raw materials and the number of requests. So far, Berkah Rasa has not had the right strategy in producing Jenang to get maximum profit. The purpose of this research is to apply integer linear programming to the optimization of Jenang Ayu and Jenang Krasikan production. The method used to solve this problem is the cutting plane method. The results of the research obtained is the optimal solution for Berkah Rasa, that is by producing 25 kg of Jenang Ayu and 22 kg of Jenang Krasikan every day. So that the benefits obtained by Berkah Rasa every day are IDR 727,000.00.

The analysis of the sensitivity of vaccination parameters in a tuberculosis transmission model

Tuberculosis (TB) is one of the most dangerous infectious diseases that caused 1,5 million people died from TB in 2018 (including 251.000 people with HIV). As the preventive strategy for the spread of TB, we can use BCG vaccination. This study aims to investigate and analyze the sensitivity of vaccination parameters (to newborns and adults). This model divided the human population into five classes: susceptible , vaccinated , high-risk and low-risk latent, and infectious . Analysis of the mathematical model was discussed by finding the existence and analyzing the model equilibrium's stability based on the Basic Reproduction Number ( ). Furthermore, we determined the sensitivity analysis of the proportion of vaccine and other parameters that affect the TB transmission model. The numerical experiment shows that vaccination to adults more effective than newborns.

Visual, auditory, and kinesthetic learning model on the mathematics problem solving ability

This study aimed to determining the effect of using VAK (Visual, Auditory and Kinesthetic) learning model on the mathematics problem solving abilities. This study utilized a quantitative method with a research design Post-Test Only Control Design. The instrument is used a test of mathematics problem solving abilities that has been validated by expert lecturers. Accordingly, the data has reliable instrument. The data in the Requirements Test analysis encompassed the normality and homogeneity tests. Hence, the variance data of the group an homogeneous distribution. Besides in the Hypothesis Test utilizing the t-test, it was attained that t count = 3.544 > ttable = 2.001. Accordingly, from the data of the two classes, H1 is accepted. Hence, There is a significant effect between the VAK (Visual, Auditory and Kinesthetic) learning model and the class that does not utilize it.

Question analysis of mathematics textbook for 2013 curriculum and IB curriculum on quadratic equations

The goal of this study is to compare the types of questions between the 2013 Curriculum Mathematics textbooks and the IB Curriculum on quadratic equations. The approach used in this research is a six-dimensional analysis method consisting of: mathematical activity, the difficulty level of the questions, the types of answers expected, the contextual situation, the types of responses, and the stages of the mathematical questions. The data collection technique is conducted by evaluating and explaining the types of questions. The types of questions were obtained from the 2013 Curriculum Mathematics textbook and the IB Curriculum based on a six-dimensional analysis, namely: mathematical activity, question complexity, type of answer, contextual situation, type of response, and mathematical questions. Based on the type, the results of this study show that the questions in the 2013 curriculum mathematics textbooks are more varied than the questions in the IB curriculum mathematics textbooks on the subject of quadratic equations. However, based on the number, there are more questions in the IB curriculum mathematics textbook than the questions in the 2013 curriculum mathematics textbook.

Learning geometry through surface creation from the hypocycloid curves expansion with derivative operators for ornaments

Geometry is one of the particular problems for students. Therefore, several methods have been developed to attract students to learn geometry. For undergraduate students, learning geometry through surface visualization is introduced. One topic is studying parametric curves called the hypocycloid curve. This paper presents the generalization of the hypocycloid curve. The curve is known in calculus and usually is not studied further. Therefore, the research's novelty is introducing the spherical coordinate to the equation to obtain new surfaces. Initially, two parameters are indicating the radius of 2 circles governing the curves in the hypocycloid equations. The generalization idea here means that the physical meaning of parameters is not considered allowing any real numbers, including negative values. Hence, many new curves are observed infinitely. After implementing the spherical coordinates to the equations and varying the parameters, various surfaces had been obtained. Additionally, the differential operator was also implemented to have several other new curves and surfaces. The obtained surfaces are useful for learning by creating ornaments. Some examples of ornaments are presented in this paper.

The practicality of the 7e learning cycle LKS model with a scientific approach to facilitate students’ mathematical connection abilities

This study aims to describe the practicality of the 7e learning cycle LKS model with a scientific approach to facilitate students' mathematical connection abilities. The research and development with the ADDIE model consist of the stages of analysis, design, development, implementation and evaluation. The practicality test of the LKS was carried out for small group trials of 9 students at the implementation stage. The method used is descriptive statistics to get the average value and percentage. Learning tools are said to be practical if their minimum level of practicality is practical. Based on the analysis of the results of student response questionnaires, the average percentage of student response questionnaires was 91.59% and was categorized as very practical. This means that this LKS is easy to use and useful for students.

Structural equation modeling-partial least squares: Analysis of the effect of hedonic value on customer satisfaction and loyalty

Testing the effect of hedonic value on loyalty, the hedonic value on satisfaction, and customer satisfaction on consumer loyalty, and investigating the effect of hedonic value on consumer loyalty with customer satisfaction as an intervening variable is the purpose of this study, with a case study on e-commerce Shopee. The sample aims to be a method of determining the sample with a total of 100 respondents. The intended respondents are Pamulang University students, Faculty of Economics, S1 Accounting Department as well as consumers of Shopee e-commerce. The Research model used SEM-PLS Structural Equation Modeling-Partial Least Square Approach. The results of this study indicate that the hedonic value has a positive influence and also has a significant value on consumer loyalty at the real level of 10%. The results of the study also state hedonic value has a significant positive effect on consumer satisfaction, and customer satisfaction has a significant positive effect on consumer loyalty with the satisfaction of consumer as a variable of intervening with 10% level.