• Journal of Korea Multimedia Society
• /
• v.21 no.2
• /
• pp.310-322
• /
• 2018

Documentation is a typical method that helps students to understand a program for implementation and execute error correction and maintenance cost-effectively. Guidelines for components that organize documentation should be provided to enable to express computational thinking and such components also should be linked to coding process. In this paper, we focused on the documentation format to guide elementary school students, who were beginners in computational thinking, to express computational thinking. The improvement in the expression of computational thinking was analyzed based on the documentation format applied to the class, and practical tips on the importance of components organizing the documentation format were proposed.

• Korean Journal of Computational Design and Engineering
• /
• v.20 no.2
• /
• pp.193-209
• /
• 2015

For reasons such as global warming, depletion of fossil fuels and the danger of nuclear energy the research and development of renewable energy is actively underway. Wind energy has advantages over another renewable energy in terms of location requirements, energy efficiency and reliability. Nowadays the research and development area is expanded to offshore because it can supply more wind reliability and free from noise pollution. In this study, the monopile offshore wind turbine transportation and installation (T&I) process are investigated. In addition, the schedule and cost for the process are estimated by discrete event simulation. For the simulation, simulation models for various means of T&I are developed. The optimum T&I execution plan with shortest duration and lowest cost can be found by using different mission start day and T&I means.

• Korean Journal of Computational Design and Engineering
• /
• v.21 no.1
• /
• pp.61-68
• /
• 2016

Since past till now, automotive wiring harness has been designed and produced under the method of part number list. However, the number of options has increased gradually on the basis of customer's needs and car manufacturer's policy, thereby bringing about an increase in the number of classified parts. Because of a large number of classified parts, cost estimates for manufacturing and production planning are more important than ever. However, the pre-existing manufacturing bill of material abbreviated as BOM is only focused on the list of materials used for actual manufacturing, and as such there have been limits to other fields or areas of usage except for manufacturing. In essence, the present paper is concerned with our study conducted on modular BOM as one of planning BOM. On such basis, we have been able to completely use a method by which to have access, make an option units' calculation in wiring harness manufacturing, and build an efficient system for cost estimates in manufacturing as well.

• Journal of Advanced Navigation Technology
• /
• v.19 no.1
• /
• pp.53-59
• /
• 2015

We consider the problems that consist of designing time, establishment cost, delay time and reliability in designing a mesh network when given link costs and traffic requirements between nodes. Designing time, establishment cost and delay time are less, reliability is higher in designing a mesh network. One of the problems designing time is solved by mesh network topology optimization and routing (MENTOR) algorithm that Aaron Kershenbaum propose, but the others remain. In this paper we propose a new mesh network design algorithm with small computational complexity that the others are solved. The result of the proposed algorithm is better than MENTOR's in total establishment cost, delay time and reliability.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2002.04a
• /
• pp.257-264
• /
• 2002

This study presents a life-cycle cost (LCC) effectiveness of a concrete with lightweight aggregate. A number of researchers have made their efforts to develop a lightweight concrete, since it is difficult to apply conventional concrete using general aggregate to heavy self-weight structures such as long span bridges. In this study, an optimum design for minimizing the life-cycle cost of concrete slab bridges is performed to evaluate the life cycle cost effectiveness of the lightweight concrete relative to conventional one from the standpoint of the value engineering. The data of physical properties for new concrete can be obtained from basic experimental researches. The material properties of conventional one are acquired by various reports. This study presents a LCC effectiveness of newly developed concrete, which is made by artificial lightweight aggregate. A number of researchers have made their efforts to develop a lightweight concrete, since it is difficult to apply conventional concrete using general aggregate to heavy self-weight structures such as long span bridges. From the results of the numerical investigation, it may be positively stated that the new concrete lead to, the longer span length, the more economical slab bridges compared with structures using general concrete.

• International Journal of Computer Science & Network Security
• /
• v.21 no.9
• /
• pp.1-10
• /
• 2021

The Internet of things (IoT) is the main advancement in data processing and communication technologies. In IoT, intelligent devices play an exciting role in wireless communication. Although, sensor nodes are low-cost devices for communication and data gathering. However, sensor nodes are more vulnerable to different security threats because these nodes have continuous access to the internet. Therefore, the multiparty security credential-based key generation mechanism provides effective security against several attacks. The key generation-based methods are implemented at sensor nodes, edge nodes, and also at server nodes for secure communication. The main challenging issue in a collaborative key generation scheme is the extensive multiplication. When the number of parties increased the multiplications are more complex. Thus, the computational cost of batch key and multiparty key-based schemes is high. This paper presents a Secure Multipart Key Distribution scheme (SMKD) that provides secure communication among the nodes by generating a multiparty secure key for communication. In this paper, we provide node authentication and session key generation mechanism among mobile nodes, head nodes, and trusted servers. We analyzed the achievements of the SMKD scheme against SPPDA, PPDAS, and PFDA schemes. Thus, the simulation environment is established by employing an NS 2. Simulation results prove that the performance of SMKD is better in terms of communication cost, computational cost, and energy consumption.

• Information Systems Review
• /
• v.16 no.1
• /
• pp.37-50
• /
• 2014

Conventional case-based reasoning (CBR) does not perform efficiently for high volume dataset because of case-retrieval time. In order to overcome this problem, some previous researches suggest clustering a case-base into several small groups, and retrieve neighbors within a corresponding group to a target case. However, this approach generally produces less accurate predictive performances than the conventional CBR. This paper suggests a new hybrid case-based reasoning method which dynamically composing a searching pool for each target case. This method is applied to diagnose for the heart disease dataset. The results show that the suggested hybrid method produces statistically the same level of predictive performances with using significantly less computational cost than the CBR method and also outperforms the basic clustering-CBR (C-CBR) method.

• Journal of applied mathematics & informatics
• /
• v.10 no.1_2
• /
• pp.131-143
• /
• 2002

In this paper hi-criterion quadratic fractional generalized solid transportation problem is studied. An algorithm is developed to obtain the time-cost trade-off pairs and hence identifies the optimum trade-off pairs giving the equal priority to both time and cost. A numerical example is illustrated to support the algorithm.

• Journal of applied mathematics & informatics
• /
• v.31 no.5_6
• /
• pp.907-912
• /
• 2013

This paper focuses on the situation of optimizing the total cost with m given messages and n network nodes. Associated with each network node, a fixed cost is incurred to the receiver if at least one message is received. The mean and variance of the total costs are obtained. Normal approximation is used. Empirical results showed that the derived method reduces research work substantially.

• Proceedings of the Korea Society for Simulation Conference
• /
• 1998.03a
• /
• pp.11-16
• /
• 1998

The classical algorithm for solving liner network flow problems are primal cost improvement method, including simplex method, which iteratively improve the primal cost by moving flow around simple cycles, which iteratively improve the dual cost by changing the prices of a subset of nodes by equal amounts. Typical iteration/shortest path algorithm is used to improve flow problem of liner network structure. In this paper we stdudied about the implemental method of shortest path which is a practical computational aspects. This method can minimize the best neighbor node and also implement the typical iteration which is $\varepsilon$-CS satisfaction using the auction algorithm of linear network flow problem