• Computers and Concrete
• /
• 제25권6호
• /
• pp.517-523
• /
• 2020

An experimental system on three point bending notched beams was established to study the fracture process of concrete. In this system, the acoustic emission (AE) was used to build the cumulative generation order (AGO) and dynamically track the process of microcrack evolution in concrete. A grey-cusp catastrophe model was built based on AE parameters. The results show that the concrete beams have significant catastrophe characteristic. The developed grey-cusp catastrophe model, based on AGO, can well describe the catastrophe characteristic of concrete fracture process. This study also provides a theoretical and technical support for the application of AE in concrete fracture prediction.

• 한국산학기술학회논문지
• /
• 제10권11호
• /
• pp.3200-3206
• /
• 2009

본 논문은 현행 국내 우편기계 유지보수 체계의 문제점을 기술하고 이에 대한 개선 방안으로 현 우편기계 유지보수 방식과 다른 방식에 대해 경제성 및 효율성 측면에서 AHP 방식에 근거하여 조사한 결과를 제시하였다. 아울러 현 우편기계 유지보수 방식에서 정의되지 않은 예방 및 고장 수리에 대한 표준 절차와 우편기계 유지보수 이력관리 및 정보 공유 체계를 위한 유지보수 기술 지원 센터 운영 모델을 제시하였다. 제안된 우편기계 유지보수 방법은 우편기계 유지보수의 안전성과 효율성에 기여할 수 있다.

• Industrial Engineering and Management Systems
• /
• 제2권1호
• /
• pp.45-54
• /
• 2003

Enterprise Resource Planning(ERP) systems offer pervasive business functionality the applications encompass virtually all aspects of the business. Understanding and managing this pervasiveness will result in a successful and productive business application platform. Because of this pervasiveness, implementations have ranged from great successes to complete failures. This article has two distinctive parts. The first proposes and discusses a systematic process based on consulting experiences of LG CNS (leading information system company in Korea) for ERP selection. Also, the second provides the key factors that are critical to the successful implementation of ERP. The second part reports the results of a study carried out to assess a number of different ERP implementations in different organizations. A case study method of investigation was used, and the experiences of five Korean manufacturing companies were documented. The critical factors in the adoption of ERP are identified as: learning from the experiences of others, appointment of a process innovator, establishment of committees and project teams, training and technical support for the users, and appropriate changes to the organizational structure and managerial responsibilities.

• 한국컴퓨터정보학회논문지
• /
• 제24권2호
• /
• pp.17-24
• /
• 2019

In this paper, we propose a new model for predicting effective Win/Loss in professional baseball game in Korea using machine learning technique. we used basic baseball data and Sabermetrics data, which are highly correlated with score to predict and we used the deep learning technique to learn based on supervised learning. The Drop-Out algorithm and the ReLu activation function In the trained neural network, the expected odds was calculated using the predictions of the team's expected scores and expected loss. The team with the higher expected rate of victory was predicted as the winning team. In order to verify the effectiveness of the proposed model, we compared the actual percentage of win, pythagorean expectation, and win percentage of the proposed model.

• 한국군사과학기술학회지
• /
• 제24권1호
• /
• pp.99-106
• /
• 2021

This study explores the improvement of storage environment of igloo-shaped magazine using forced ventilation. Conjugate heat transfer analysis of forced convection and conduction are performed to calculate the flow, temperature, and relative humidity field in igloo-shaped magazine. Through the conjugate heat transfer analysis, the effects of inlet vent, volume flow rates of jet, and jet angles on the condensation and relative humidity are numerically investigated. The area of condensation in igloo-shaped magazine and relative humidity at the surface of ammunitions are then calculated.

• 한국산업융합학회 논문집
• /
• 제26권3호
• /
• pp.463-470
• /
• 2023

In this study, an electronic parts assembly training system using Leap Motion was developed in consideration of the processes actually operated in the assembly process of electronic products. Based on Leap Motion and Oculus VR equipment, the system was developed to transfer user's hand movement data in real time and convert it into hand movement in virtual space so that electronic parts assembly simulation can be performed step by step. Through this, it was confirmed that the user can obtain an experience similar to the actual electronic parts assembly work, prevent errors that may occur during the assembly process, and improve proficiency. It is expected that this thesis will provide directions for the quality improvement and development of various education and training programs for virtual reality-based manufacturing processes.

• 방사성폐기물학회지
• /
• 제21권3호
• /
• pp.419-425
• /
• 2023

The Radiation and Decommissioning Laboratory of Central Research Institute (CRI) of Korea Hydro and Nuclear Power Co. (KHNP) performs research to technically support the effective management of radiological hazards to avoid risks to civilians, the workers, and the environment from the radiological risks. The laboratory mainly consists of three technical groups: decommissioning and SF technology group, radiation and chemistry group, and radwaste and environment group. The groups carry out various R&D such as decommissioning, spent fuel management, radiation protection, water chemistry management, and radioactive waste management. The laboratory also technically supports the calibration of radiometric instruments as a Korea Laboratory Accreditation Scheme (KOLAS), approval for decommissioning, guidance for radioactive waste management, state-of-the-art technology evaluations, and technology transfer.

• Structural Engineering and Mechanics
• /
• 제64권5호
• /
• pp.671-681
• /
• 2017

This study investigates the structural performance of 3D steel pipe rack suspended scaffolding systems. For the purpose, a standard full scale 3D steel pipe rack suspended scaffolding system considering two frames, two plane trusses, purlins and wooden floor is constructed in the laboratory. A developed load transmission system was placed in these experimental systems to distribute single loads to the center of a specific area in a step-by-step manner using a load jack. After each load increment, the displacements are measured by means of linear variable differential transducers placed in several critical points of the system. The tests are repeated for five different system conditions to determine the structural performance. The means of system conditions is the numbers of the tie bars which are used to connect plane trusses under level. Finite elements models of the 3D steel pipe rack suspended scaffolding systems considering different systems conditions are constituted using SAP2000 software to support the experimental tests and to use the models in future studies. Each of models including load transmission platform is analyzed under a single loading and the displacements are obtained. In addition, to calibrate the numerical models some uncertain parameters such as elasticity modulus of wooden floor and connection rigidity of purlins to plane trusses are assessed experimentally. The results of this work demonstrate that when increasing numbers of tie bars the displacement values are decreased. Also the results obtained from developed numerical models have harmony with those of experimental. In addition, the scaffolding system with two tie bars at the beginning and at the end of the plane truss has the optimum structural performance compared the results obtained for other scaffolding system conditions.

• Nuclear Engineering and Technology
• /
• 제56권1호
• /
• pp.147-159
• /
• 2024

Plutonium-238 has always been considered as the one of the promising radioisotopes for space nuclear power supply, which has long half-life, low radiation protection level, high power density, and stable fuel form at high temperatures. The industrial-scale production of ²³⁸Pu mainly depends on irradiating solid ²³⁷NpO₂ target in high flux reactors, however the production process faces problems such as large fission loss and high requirements for product quality control. In this paper, a conceptual design study of producing ²³⁸Pu in a multi-purpose high flux reactor was evaluated and analyzed, which includes a sensitivity analysis on ²³⁸Pu production and a further study on the irradiation scheme. It demonstrated that the target structure and its location in the reactor, as well as the operation scheme has an impact on ²³⁸Pu amount and product quality. Furthermore, the production efficiency could be improved by optimizing target material concentration, target locations in the core and reflector. This work provides technical support for irradiation production of ²³⁸Pu in high flux reactors.

• 비파괴검사학회지
• /
• 제29권3호
• /
• pp.214-218
• /
• 2009

The occlusal force of the tooth leads to loss of tooth tissue owing to attrition and abrasion, and may cause abfraction and pathological change of the dentin. Thus, we developed finite element models, examined them by applying ordinary occlusal force, and analyzed the stress distribution. Specimens used were mandibular first premolars from 15 Korean males and 13 females and were made into finite element models from medical images that were obtained using a Micro-CT. We have found that the irregular feature of the tooth is not only useful to masticating and pronouncing as well known, but it is also suitable for protecting inner tissue by dispersing stress and delivering proper pressure to periodontal tissue to continue a physiological action. Also, image analysis could let us know the factor that is the cause of a disorder due to stress concentration in the cervical line. These results are expected to support the field of dental treatment planning, operating procedure and clinical trial, and the advance of technical expertise to develop implants and dentures.