• Information Systems Review
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• v.22 no.1
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• pp.1-16
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• 2020

Blockchain is emerging as a technology that can build trust between users participating in the system. As interest of Blockchain has increased, previous studies have mainly focused on cryptocurrency and application methods related to Blockchain technology. On the other hand, the studies on the stable implementation of Blockchain were rarely conducted. Typically, uncle block in the Blockchain plays an important role in the stable implementation of the Blockhain system, but no study was conducted on this. Drawing on this recognition, this study attempts to predict the uncle block of Blockchain using machine learning method, Blockchain information, and macro-economic factors. The results of artificial neural network and support vector machine analysis, Blockchain information and macro-economic factors contributed to the prediction of uncle block of Blockchain. In addition, artificial neural network using only Blockchain information provided the best performance for predicting the occurrence of uncle block. This study suggests ways to lead and contribute to Blockchain research in information systems filed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.5
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• pp.341-347
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• 2003

This paper presents an improved escalator dynamic model so as to reflect the experimental observation on the pseudo-resonance affected by load applied. The experimental evidence reveals that backlash on gearbox as well as sag of driving Chain are most critical factors to the pseudo-resonance in escalators. The dynamic model effectively reflects vibration characteristics measured in real escalators with respect to different conditions of driving chain and the number of passengers. For validation of the dynamic model developed. numerical results from the model are compared with experimental results. The developed model and its simulation results are used rigorously for the design of escalator systems in enhancing the ride comfort.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.238-243
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• 2002

This paper presents an improved escalator dynamic model so as to reflect the experimental observation on the pseudo-resonance affected by load applied. The experimental evidence reveals that backlash of gearbox as well as sag of driving chain are most critical factors to the pseudo-resonance in escalators. The dynamic model effectively reflects vibration characteristics measured in real escalators with respect to different conditions of driving chain and the number of passengers. For validation of the dynamic model developed, numerical results from the model are compared with experimental results. The developed model and its simulation results are used rigorously for the design of escalator systems in enhancing the ride comfort.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.329.2-329
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• 2002

This paper presents an improved escalator dynamic model so as to reflect the experimental observation on the pseudo-resonance affected by load applied. The experimental evidence reveals that backlash of gearbox as well as sag of driving chain are most critical factors to the pseudo-resonance in escalators. The dynamic model effectively reflects vibration characteristics measured in real escalators with respect to different conditions of driving chain and the number of passengers. (omitted)

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.342-343
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• 2004

조사재시험시설내 풀 ($3{\times}6{\times}10\textrm{m}^3$) 속에는 풀과 핫셀간에 조사재 및 연료를 핫셀로 이송할 수있는 버켓 엘리베이터(bucket elevator)가 설치되어 있다. 허용하중은 1톤이고, 버켓의 제원은 $25{\times}25{\times}150\textrm{cm}^3$ 이다. 버켓의 상하 운동은 체인구동 시스템으로 약 63도의 경사도를 갖고 움직이며, 체인은 사각 튜브의 내측면에 고정되어 있는 상하 가이드 레일 사이에서 특수 제작된 체인이 로울러 슬라이딩 방식으로 버켓의 lug를 잡고 상하로 움직이며 핫셀 작업대(working table) 하부에 설치되어 있는 스프로켓 휠(sprocket wheel)에 감기어 구동하도록 되어 있다.(중략)

• Journal of KSNVE
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• v.10 no.4
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• pp.692-701
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• 2000

Escalators are widely used for mass transportation in public places. In recent years, strict requirements on the comfort and reliability for the public transportation have drawn a great attention to vibration in escalators. This paper presents a dynamic model for escalators to be used for the analysis and design of low vibration escalators. The dynamic model is developed so as to reflect the physical observation on peculiar characteristics in escalators such as the difference between up-moving and down-moving, and the abnormal vibration affected by the load applied. For validation of the dynamic model developed, experimental results are compared with numerical results from the model. The numerical study shows that the developed model may be useful for the analysis and design of escalator systems.

• Journal of the Korean Institute of Gas
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• v.26 no.2
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• pp.9-13
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• 2022

Electric wheelchairs, the output from the motor is mainly applied to a speed reducer using a power transmission device such as a belt or a chain. However, although a speed reducer using a belt or chain is a simple device, it occupies a lot of space and has a space limitation, so it is not suitable for an electric wheelchair driving part. However, since the speed reducer of the planetary gear type is decelerated on the same axis, the volume can be reduced, so the space constraint is less than that of the belt or chain type reducer. Therefore, in this study, a driving part that can obtain great propulsion with a speed reducer using a planetary gear type was developed through a study on the driving part of a wheelchair that can be switched between manual and electric. Accordingly, the tooth shape of the planetary gear applied to the reducer was designed using the Kisssoft program. In addition, the drive part was designed to be applicable to the existing wheelchair wheels, and the mechanism was optimized for the manual/electric switching principle and operation principle of the drive part. Based on the research contents, the final design and manufacture of the wheelchair reducer drive unit in the form of a planetary gear having one sun gear, two planetary gears and one ring gear was carried out.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.260-263
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• 2018

현재까지 공항에서의 체크인 시스템은 기본적으로 서버-클라이언트(Server-Client)방식으로 구동되어져왔다. 서버-클라이언트 방식에서 서버는 단일실패지점이기 때문에 천재지변이나 공격자에 의해 서버마비와 같은 문제가 생기면 체크인 시스템 전체가 마비될 수 있다. 뿐만 아니라 실제 해커에 의해 항공사 중앙 서버가 공격을 받게 되면, 서버가 관리하는 항공사 데이터들의 무결성이 훼손될 수도 있다. 따라서 단일 실패지점에 대한 위협을 제거함과 동시에 저장된 데이터들의 무결성을 유지하는 방법을 논의할 필요가 있다. 그 중 하나로 블록체인 기술을 이용한 탈중앙화 시스템(Decentralized System) 모델을 적용하는 방법이 있다. 본 논문에서는 스마트 계약을 이용한 블록체인 기반 공항 체크인 시스템에 대한 모델을 제안한다.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.1
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• pp.22-27
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• 2012

This paper presents a ball screw-driven robotic gripper mechanism which is possible to grasp an object and analyzes its kinematic feature for grasping by simulation. For the purpose of identifying the feature of the robot gripper, we try to confirm the kinematics relating the joint space of the driving actuator to the gripper's tip space. To be specific, the proposed robot gripper employs one actuator and a symmetrical closed-chain structure. As a result, the specified robot gripper has an advantage of robustness to external forces structurally, and it is easy to implement simple grasping operations. Also the gripper has a useful squeezing effect for power grasping.

• Journal of KSNVE
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• v.10 no.5
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• pp.830-837
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• 2000

This paper deals with an analysis and countermeasure of escalator vibration. The vibration characteristics of escalators are studied theoretically and experimentally to fine the main cause of severe vibration. The main source of vibration in escalators is found to be chordal effect due to the step chain and sprocket system. It is also found that the vibration become significantly large at so called no load condition, in which the load due to passengers, during down-moving, is equal to the resistive force in the driving system. Dynamic absorbers are implemented to suppress the vibration, A theoretical analysis is made to determine the appropriate dynamic absorber. Theoretical and experimental study shows that dynamic absorber is effective to suppress the vibration in escalators.