• Journal of Sensor Science and Technology
• /
• v.26 no.4
• /
• pp.274-279
• /
• 2017

LCD(Liquid Crystal Display) panel cutting problem is a sort of two dimensional cutting stock problem. A cutting stock problem is problem that it minimizes the loss of the stock when a stock is cut into various parts. In the most research of the two dimensional cutting stock problem, it is supposed that the relative angle of a stock and parts is not important. Usually the angle is regarded as horizontal or perpendicular. In the manufacturing of polarizing film of LCD, the relative angle should be maintained at some specific angle because of the physical and/or chemical characteristics of raw material. We propose a mathematical model for solving this problem, a two-dimensional non-Guillotine cutting stock problem that is restricted by an arranged angle. Some example problems are solved by the C++ program using ILOG CPLEX classes. We could get the verification and validation of the suggested model based on the solutions.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.45 no.4
• /
• pp.134-141
• /
• 2022

Transportation in urban area has been getting hard to fulfill the demand on time. There are various uncertainties and obstacles related with road conditions, traffic congestions, and accidents to interrupt the on-time deliveries. With this situation, the last mile logistics has been a keen issue for researchers and practitioners to find the best strategy of the problem. A way to resolve the problem is to use parcel lockers. Parcel locker is a storage that customers can pick up their products. Transportation vehicles deliver the products to parcel lockers instead of all customer sites. Using the parcel lockers, the total delivery costs can be reduced. However, the inconvenience of customer has to increase. Thus, we have to optimal solution to balance between the total delivery costs and customers' inconvenience. This paper formulates a mathematical model to find the optimal solution for the vehicle routing problem and the location problem of parcel lockers. Experimental results provide the viability to find optimal strategy for the routing problem as well as the location problem.

• Industrial Engineering and Management Systems
• /
• v.13 no.4
• /
• pp.421-431
• /
• 2014

The market basket data in the form of a binary user-item matrix or a binary item-user matrix can be modelled as a binary classification problem. The binary logistic regression approach tackles the binary classification problem, where principal components are predictor variables. If users or items are sparse in the training data, the binary classification problem can be considered as a cold-start problem. The binary logistic regression approach may not function appropriately if the principal components are inefficient for the cold-start problem. Assuming that the market basket data can also be considered as a special regression problem whose response is either 0 or 1, we propose three supervised learning approaches: random forest regression, random forest classification, and elastic net to tackle the cold-start problem, comparing the performance in a variety of experimental settings. The experimental results show that the proposed supervised learning approaches outperform the conventional approaches.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.32 no.3
• /
• pp.118-126
• /
• 2009

This research investigates the problem of minimizing setup costs in resequencing jobs having first-in, first-out(FIFO) constraints at conveyorized production or assembly systems. Sequence changing at conveyor junctions in these systems is limited due to FIFO restriction. We first define the general problem of resequencing jobs to workstations satisfying precedence relationships between jobs(Generalized Sequential Ordering Problem, GSOP). Then we limit our scope to FIFO precedence relationships which is the conveyor selection problem at a diverging junction(Diverging Sequential Ordering Problem, DSOP), modeling it as a 0-1 integer program. With the capacity constraint removed, we show that the problem can be modeled as an assignment problem. In addition, we proposed and evaluated the heuristic algorithm for the case where the capacity constraint cannot be removed. Finally, we discuss the case study which motivated this research and numerical results.

• Journal of Navigation and Port Research
• /
• v.29 no.2
• /
• pp.141-146
• /
• 2005

For a long time, genetic algorithms have been recognized as a new method to solve difficult and complex problems and the performance of genetic algorithms depends on genetic operators, especially crossover operator. Various problems like the traveling salesman problem, the transportation problem or the job shop problem, in logistics engineering can be modeled as a sequencing problem This paper proposes modified genetic crossover operators to be used at various sequencing problems and uses the traveling salesman problem to be applied to a real world problem like the delivery problem and the vehicle routing problem as a benchmark problem Because the proposed operators use parental information as well as network information, they could show better efficiency in performance and computation time than conventional operators.

• Journal of Practical Engineering Education
• /
• v.7 no.1
• /
• pp.11-16
• /
• 2015

Learners acquire knowledge through many years of majors and educated classes. They convergence of engineering problem solving that combine a variety of subjects are difficult. In this paper, we suggest practical engineering problem solving model combined major educational courses for example optimization problem of heat sink temperature reduction.

• Structural Engineering and Mechanics
• /
• v.37 no.1
• /
• pp.61-77
• /
• 2011

Static and dynamic responses of a completely free elastic beam resting on a two-parameter tensionless Pasternak foundation are investigated by assuming that the beam is symmetrically subjected to a uniformly distributed load and concentrated load at its middle. Governing equations of the problem are obtained and solved by paying attention on the boundary conditions of the problem including the concentrated edge foundation reaction in the case of complete contact and lift-off condition of the beam ina two-parameter foundation. The nonlinear governing equation of the problem is evaluated numerically by adopting an iterative procedure. Numerical results are presented in figures to demonstrate the non-linear behavior of the beam-foundation system for various values of the parameters of the problem comparatively by considering the static and dynamic loading cases.

• Journal of Engineering Education Research
• /
• v.21 no.5
• /
• pp.20-31
• /
• 2018

The purpose of this study was to investigate the relationship between instructional strategies applied to engineering courses and students' learning strategies. As a result, students perceived that the application principle was the most applied and then the problem-centered principle was applied to engineering courses. In addition, the students showed that rehearsal strategies are the most used in courses. The most important instructional principle in this study was the problem-centered principle, and the higher the degree of application of problem-centered principle in engineering course, the students were likely to use more deep learning strategies such as elaboration and organization strategy, critical thinking strategy, and metacognitive strategy.

• Korean Journal of Childcare and Education
• /
• v.19 no.4
• /
• pp.29-52
• /
• 2023

Objective: This research aims to examine the effect of a young children's engineering-focused STEAM program based on the project approach - a program that constructs components aligned with children's interests in their play through an engineering design process - on their scientific inquiry ability, mathematical problem-solving ability, and creativity. Methods: In this research, 42 five-year-old children from a public kindergarten in S district, I city, were randomly divided into experimental and comparative groups, each with 21 children. The engineering-focused STEAM program was conducted from April 18 to June 10, 2022, with the experimental group exploring the 'car' theme and the comparison group focusing on a different theme. The study employed an independent sample t-test and analysis of covariance(ANCOVA), using the pretest as a covariate to control variables. Results: The children-selected 'cars' themed engineering-focused STEAM program was effective in enhancing their scientific inquiry ability, mathematical problem-solving ability and creativity. Conclusion/Implications: The engineering-focused STEAM program, which emerges from young children's interesting daily play, had positive effects on enhancing their scientific inquiry ability, mathematical problem-solving ability, and creativity. This research can serve as fundamental data for developing education programs focused on engineering within the STEAM framework, guided by children's emergent play.

• Journal of Korean Institute of Industrial Engineers
• /
• v.28 no.1
• /
• pp.99-104
• /
• 2002

This paper presents a method of sensitivity analysis for the infeasible interior point method when a new variable is introduced. For the sensitivity analysis in introducing a new variable, we present a method to find an optimal solution to the modified problem. If dual feasibility is satisfied, the optimal solution to the modified problem is the same as that of the original problem. If dual feasibility is not satisfied, we first check whether the optimal solution to the modified problem can be easily obtained by moving only dual solution to the original problem. If it is possible, the optimal solution to the modified problem is obtained by simple modification of the optimal solution to the original problem. Otherwise, a method to set an initial solution for the infeasible interior point method is presented to reduce the number of iterations required. The experimental results are presented to demonstrate that the proposed method works better.