Many students in the world have difficulty in solving word problems, including students in Indonesia. TIMSS has shown that only eight percent of Indonesian participants are able to solve word problems, this result is hugely lower than the international average of 18 percent. One of the factors that cause students' errors in solving word problems is mathematical resilience. Thus, this study aims to analyze students' misconceptions in solving word problems viewed by their mathematical strength. This study was conducted for sixth-grade students in one of the elementary schools in Bandung. This study was qualitative descriptive research. In this study, there were four steps: selecting the word problems, answering the issues, filling out a mathematical resilience questionnaire, and interviewing. Students were encouraged to respond to a three-word question within 30 minutes, filling out a mathematical resilience questionnaire followed by the interview. This study showed that the students' errors in solving word problems were including comprehension, transformation, and process skill errors. Based on mathematical resilience, students with a low level of resilience predominantly carried out comprehension errors. In contrast, students with a moderate level of resilience more dominant made transformation errors. Meanwhile, students with high resilience completed more questions correctly, although several students seemed to have made process skills errors. This study's limitation is the data obtained online so that the respondents completed the instrument exceeds the given time. Further researches are suggested to conduct directly in the classroom to maximize the accuracy of the study.

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Abstract. We consider two-dimensional cutting stock problems where single rectangular stocks have to be cut into some smaller rectangular so that the number of stocks needed to satisfy the demands is minimum. In this paper we focus our study to the problem where the stocks have to be cut with guillotine cutting type and fixed orientation of finals. We formulate the problem as an integer programming, where the relaxation problem is solved by column generation technique. New pattern generation is formulated based on method of stripe. In obtaining the integer solution, we round down the optimal solution of the relaxation problem and then we derive an extra mix integer programming for satisfying the unmet demands. The optimal solution of the original problem is the combination of the round-down solution and the optimal solution of the extra mix integer programming.A numerical example of the problem is given in the end of this paper.

Abstract. This paper discusses Indonesia, taking into account regulations. These internal labor regulations are in general more restrictive at Garuda Indonesia than at other airlines, so that modeling the cockpit crew rostering problem for Garuda Indonesia is challenging. We ha mathematical expressions for the cockpit crew labor regulations and some technical matters. We model problem, using the average relative deviation of total flight time to the ideal flight time as the objective function. for all classes of cockpit crews of Garuda Indonesia, using a simulated annealing method for solving the problem. We obtained satisfactory ro members in a short amount of computing time. This shows that the optimization problem is well-defined.

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