• Journal of Navigation and Port Research
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• v.33 no.5
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• pp.331-337
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• 2009

Container crane is main equipment in container terminals and it determines the productivity and the efficiency of container terminals. The typical type of container cranes has the single trolley and one among advanced types of them has the dual trolley. The objective of this paper is to analyze the buffer size of a container crane with the dual trolley in container terminals. We present a simulation model for analysing the buffer space of a container crane with the dual trolley. The buffer space is located between main trolley in sea-side and second trolley in yard-side. We performs various simulation experiments and analyze the buffer size to estimate the required productivity.

• Journal of the Korea Society for Simulation
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• v.33 no.2
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• pp.1-11
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• 2024

A cyber-physical system is a technology that connects the physical systems of a manufacturing environment with a cyber space to enable simulation. One of the major challenges in this technology is the seamless communication between these two environments. In complex manufacturing processes, it is crucial to adapt to various protocols of manufacturing equipment and ensure the transmission and reception of a large volume of data without delays or errors. In this study, we propose a method for constructing agent models for real-time simulation-capable cyberphysical systems. To achieve this, we design data collection units as independent agent models and effectively integrate them with existing simulation tools to develop the overall system architecture. To validate the proposed structure and ensure reliability, we conducted empirical testing by integrating various equipment from a real-world smart microfactory system to assess the data collection capabilities. The experiments involved testing data delay and data gaps related to data collection cycles. As a result, the proposed approach demonstrates flexibility by enabling the application of various internal data collection methods and accommodating different data formats and communication protocols for various equipment with relatively low communication delays. Consequently, it is expected that this approach will promote innovation in the manufacturing industry, enhance production line efficiency, and contribute to cost savings in maintenance.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.5
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• pp.45-52
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• 2015

The read performance of hybrid hard disk is better than the legacy hard disk and power consumption is also considerably low. As blocks with enough localities may be located in the non-volatile cache whose size is generally limited, an effective block replacement scheme is required. As this replacement is inevitably affected by various parameters, we define this issue as a kind of multiple criteria decision model. To solve this problem, this paper suggests a new block replacement algorithm based on the analytic hierarchy process. Through simulation for our model, we confirmed that the proposed model could be used as a replacement algorithm of the hybrid hard disk as it may improve boot time as well as response time of general applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.61-69
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• 2016

Since 2000, the market of convenient stores in Korea has developed rapidly due to the explosive growth in single households but it still consists mainly of manual work due to the nature of the domestic industry. Hence the explosive increase in demand in the market is mostly due to workers. Therefore, the research aimed at encouraging efficiency via automation, which is carried out in manufacturing, such as electronic, cars and so on, is inadequate. This study performed a feasibility analysis of investment for introducing an automated system on brand A, which is domestic famous convenience store company. Productivity growth according to the introduction of an automated guided vehicle and the cost-benefits was studied with using a simulation for the picking process, which is most personnel and time consuming. As a result, the simulation showed that the equipment AGV introduced for choosing the process has the effects of cost saving and increased time efficiency for performing manual labor. Furthermore, appropriate numbers of AGV were forecasted considering the capacity of the distribution Center in the brand A convenient store, which has been growing steadily. There are increasing numbers of worker labor costs in the distribution industry these days. Before building a large new automate center, it is expected to provide a good information to investors who are considering increasing productivity through partial automation of each of unit process to achieve some cost reduction.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.6
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• pp.543-548
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• 2002

It is well known that FCM is an indispensible tool for fuzzy clustering. The problems of using FCM are 1) it is sensitive to the initial random membership functions and 2) FCM inherently requires the number of clusters. Hence we need to run FCM algorithms with an appropriate validity measure until we find a suitable number of clusters. In this paper, we suggest the Majority-Voting FCM with implied validity measure. With this algorithm, we can solve the aforementioned problems. The working simulation results are provided. The contributions are 1) MV-FCM algorithm and 2) its definitive capability of being an excellent validity measure.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.649-651
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• 2017

A clustering problem is one of the organizational problems to improve the network lifetime and scalability in wireless ad-hoc networks. This problem is a difficult combinatorial optimization problem associated with the design and operation of these networks. In this paper, we propose an efficient clustering algorithm to maximize the network lifetime and consider scalability in wireless ad-hoc networks. The clustering problem is known to be NP-hard. We thus solve the problem by using optimization approaches that are able to efficiently obtain high quality solutions within a reasonable time for a large size network. The proposed algorithm selects clusterheads and configures clusters by considering both nodes' power and the clustering cost. We evaluate this performance through some experiments in terms of nodes' transmission energy. Simulation results indicate that the proposed algorithm performs much better than the existing algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3A
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• pp.244-257
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• 2009

We analysed the opportunistic scheduling method in MMR proposed by Samsung Electronic Cooperation and confirmed the efficiency by simulation. We also investigated the relationship between the throughput and fairness under the proposed method. The main objective of this study is to propose an opportunistic packet scheduling method in MMR, which considers the QoS requirement of user. Using the simulation the performance of the proposed method is compared with those of i) pure opportunistic packet scheduling method which doesn't consider QoS requirement and ii) packet scheduling method which only consider the QoS requirement, but does not utilize opportunistic packet scheduling.

• Journal of Korea Game Society
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• v.19 no.1
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• pp.5-14
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• 2019

This paper presents a practical method to compute the closest approach distance of two ellipsoids in their inter-center direction. This is the key technique for collision handling in the dynamic simulation of rigid and deformable bodies approximated with ellipsoids. We formulate a set of equations with the inter-center distance and the contact point and normal for the two ellipsoids contacting each other externally. The equations are solved using fixed-point iteration and Aitken's delta-squared process. In addition, we introduce a novel stopping criterion expressed in terms of the error in distance. We demonstrate the efficiency and practicality of our method in various experiments.

• Journal of Internet of Things and Convergence
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• v.9 no.6
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• pp.75-81
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• 2023

This study propose the traffic shaping scheme on IoT Network. The proposed scheme can be operated on the gateway which called sink node and control the IoT traffic with considering the traffic type(real-time based or non real-time based). It is proved that the proposed scheme shows a efficient and compatible result by the numerical analysis and the simulation on the proposed model. And the efficient of the proposed scheme by the numerical analysis has a approximate result of the simulation.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.4
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• pp.472-487
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• 1999

본 논문에서는 효율적인 이동성 관리를 위한 이동성 예측 기법을 소개한다. 이동 컴퓨팅 환경에서는 사용자가 지리적 위치의 제약없이 언제, 어디서나 다른 네트워크 시스템과 메시지를 주고 받을수 있다. 그러나, 통신자원의 부족, 잦은 접속단절 , 사용자의 움직임 등과같은 이동 컴퓨팅 시스템의 특징 때문에, 지능적이고 효율적인 이동성관리가 요구된다. 이동 컴퓨팅 시스템이 지능적이고 효율적인 이동성관리를 통하여 높은 질의 서비스를 제공하기 위해서는 이동 사용자의 움직임 패턴들을 능동적으로 고려하는 것이 바람직하다. 본 논문에서는 이동 사용자의 과거수일, 수개월동안의 움직임 패턴 즉, 이동사용자의 위치연혁으로부터 미래 위치를 예측하는 지능적 이동성 예측기법(intelligent mobility prediction scheme)을 제안한다. 모델링 방법으로서 뉴로-퍼지 추론시스템(neuro-fuzzy inference system)을 이용한다. 뉴로-퍼지 추론 시스템이 이동 사용자가 움직이게 되는 미래 위치를 예측하기 때문에 , 본 논문에서의 이동성 예측 기법은 통신채널의 사전 배당, 부족한 자원의 사전 할당등을 위해서 사용될 수 있다. 게다가, 본 논문의 시뮬레이션 결과는 제안하는 기법이 다양한 이동 환경에 대해서 높은 예측 정확도를 갖음을 보여준다.