• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2002년도 추계학술대회 논문집
• /
• pp.440-445
• /
• 2002

The characteristic equation for regenerative chatter loop including a delay element replaced by a rational function is presented by a linear differential-difference equation, accounting for the dynamics of the AMB controllers, the uncut chip thickness equation and the cutting process as well as the rigid spindle dynamics itself. The chatter stability analysis of a rigid milling spindle suspended by 5-axes active magnetic bearings(AMBs) is also performed to investigate the influences of the damping and stiffness coefficients of AMBs on the chatter free cutting conditions, as they are allowed to vary within the stable region formed by the AMB control gains. Several cutting tests varying the derivative gains of the AMB were performed to investigate the regenerative chatter vibrations, and it was concluded that the theoretical analysis results are in good consistency with the test results.

• 한국컴퓨터정보학회논문지
• /
• 제23권10호
• /
• pp.81-86
• /
• 2018

In the field of mobile games, social network games are steadily increasing in market scale and public interest every year. This paper proposes a method to design a social network game, which is one of the most successful genres in mobile games. The method uses Unity3D, the most commonly used engine for mobile game development. NGUI, a versatile developmental tool of Unity3D, is used to create shops and battle UIs. This paper particularly focuses on how to use the web hosting service to search and operate the necessary data from the database in the server. In addition, the proposed social network game is easy to implement real-time battle using Animator and Raycast, and is characterized by efficient battle implementation through time delay using Coroutine function.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2017년도 추계 학술논문 발표대회
• /
• pp.187-188
• /
• 2017

Korean government is trying to adopt 'CM at Risk(CMR)' method to solve some problems of traditional project delivery method such as cost increase, delay, low quality. Pre-construction service(PCS) is a project management methodology of CMR and BIM is the best tool for efficient PCS execution. PCS is consisted of several main items such as Target costing, Cost trending, GMP, Design optimization, Constructability review and Productivity. The purpose of this research is to analyse contractor's PCS application case result and to find improvement items.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제12권1호
• /
• pp.15-19
• /
• 2006

RNA interference has been used as a powerful tool in preventing virus proliferation in many species. In this study, we injected the dsRNA in vitro transcripts into Bombyx mori to investigate the resistance to B. mori nuclear polyhedrosis virus (BmNPV). Through vivisectional observation and real-time quantities PCR analysis, we found that these dsRNA can prevent the BmNPV to a certain extent, and delay the viruses' proliferation.

• 한국군사과학기술학회지
• /
• 제22권3호
• /
• pp.425-432
• /
• 2019

Modeling and Simulation(M&S) has widely been used in various areas such as industry, academy and military. Especially, military have used the technology for acquisition, training, and combat assessment. In this paper, we introduce our experience using M&S technique to analyze the network traffic amount and packet delay time between two military bases. For this, we modeled the current network configuration of the military bases and simulated the model with NS-3 tool. The result provided us for an insight regarding the required network performance between two bases.

• 국제학술발표논문집
• /
• The 3th International Conference on Construction Engineering and Project Management
• /
• pp.1334-1339
• /
• 2009

To achieve the best performance of a project, uncertainties involved in the building construction process need to be identified in the planning phase of the project. Uncertainties seldom create a positive impact on construction project, but they almost cause delay and increase costs. Therefore, risk management plays a significant role in construction to minimize risk occurred due to uncertainties of a project. Although the importance of the risk management has been known to the construction industry, it is not enough to be developed to meet the demands of the industry. It has not been enough for Systems to control schedule risks for managers in the field. Therefore, a tool is necessary to efficiently control risks. The propose of this study is to invent Schedule Risk Control System Module to prepare for risks in preconstruction phase.

• 국제학술발표논문집
• /
• The 3th International Conference on Construction Engineering and Project Management
• /
• pp.1161-1165
• /
• 2009

Safety of workers and productivity in construction site are affected according to the conflict status of work spaces which are performed at a time. The interference among the work spaces in construction site should be minimized because it becomes a blocking factor that causes construction delay and low productivity. Those factors can be managed by reasonable H&S (Health & Safety) practice. This research suggests the requirements of H&S practice and rules to establish the strategy of H&S management based on the literature reviews related to H&S rule. The suggested H&S rule can be visualized for searching space conflict point if the rule is linked with visual simulation tool. Accordingly the research results can be used for improving and visualizing construction productivity by work space control in 4D/nD CAD system.

• 한국정밀공학회지
• /
• 제12권5호
• /
• pp.25-32
• /
• 1995

In highly automated milling process, in-process monitoring of the malfunction is indispensable to ensure efficient cutting operation. Among many malfunctions in milling process, chatter vibration deteriorates surface finish, tool life and productivity. In this study, the monitoring system of chatter vibration for face milling process is proposed and experimentally estimated. The monitoring system employs two types of sensor such as cutting force and acceleration in sensory detection state. The RMS value and band frequency energy of the sensor signals are extracted in time domain for the input patterns of neural network to reduce time delay in signal processing state. The resultes of experimental evaluation show that the system works well over a wide range of cutting conditions.

• East Asian mathematical journal
• /
• 제40권1호
• /
• pp.119-125
• /
• 2024

Predicting the number of ICU patients holds significant importance, serving as a critical aspect in efficiently allocating resources, ensuring high-quality care for critically ill individuals, and implementing effective public health strategies to mitigate the impact of diseases. This research focuses on estimating ICU patient numbers through the development of a simple mathematical model. Utilizing data on confirmed COVID-19 cases and deaths, this model becomes a valuable tool for predicting and managing ICU resource requirements during the ongoing pandemic. By incorporating historical data on infected individuals and fatalities from previous weeks, we establish a straightforward equation. We found the substantial impact of the delay in infected individuals, particularly those occurring more than five weeks earlier, on the accuracy of ICU predictions. Proactively preparing for potential surges in severe cases becomes feasible by forecasting the demand for intensive care beds, ultimately improving patient outcomes and preventing excessive strain on medical facilities.

• 한국정보통신학회논문지
• /
• 제20권6호
• /
• pp.1171-1176
• /
• 2016

VANET은 차량간의 통신 기능을 제공하는 MANET 분야 중의 하나이다. 본 논문에서는 차량간의 통신, 차량 움직임 특징을 나타내는 모델과 그리고 실제 차량 움직임 모델을 이용한 VANET 시뮬레이터을 제안한다. VANET은 테스트를 수행하기 위해 트래픽 시뮬레이터와 네트워크 시뮬레이터가 함께 사용되어여야 한다. 하지만 시뮬레이터는 단순하고 쉽고 가격적인 면 때문에 트래픽 시뮬레이터보다 선호한다. 본 논문의 목적은 도시 환경 시나리오에 대해 테스트 목적으로 사용될 수 있는 차량 에드혹 네트워크의 시뮬레이션을 구현하는데 있다. 구현된 시뮬레이션 환경은 VANET에서 더 나은 MAC 프로토콜을 디자인하는데 사용될 수 있다. 구현된 시뮬레이션 성능을 평가하기 위해 AODV와 DSDV 라우팅 프로토콜의 성능을 평가하였다. 성능 비교는 처리율, 패킷 손실, 종단간의 지연을 이용하였다. 성능 비교 결과 DSDV가 AODV보다 처리율, 종단간의 지연, 그리고 패킷 손실에서 성능이 우수함을 보였다.