• Journal of the Korean Society for Nondestructive Testing
• /
• v.18 no.5
• /
• pp.357-364
• /
• 1998

To investigate accuracies between intensity method and count method for measurement of the fiber orientation distribution, fiber orientation function is derived by drawing simulation figure for the fiber orientation as varying fiber aspect ratio, fiber area ratio, and fiber orientation state, respectively. The values of fiber orientation function measured by intensity method and count method are compared with the calculated ones from simulation figures. The results show that measurement accuracy of fiber orientation angle distribution obtained by count method is by 4% higher than that by intensity method.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.24 no.3
• /
• pp.189-197
• /
• 2014

A simplified model in the shape of a wedge box with an opening on the roof was used to generate buffeting conditions at HMC. These measurements performed in controlled conditions are intended to validate the ability of CFD tools to predict buffeting. The results obtained by PowerFLOW are presented in this paper for buffeting and for the boundary layer development on the roof of the model when the roof opening is closed. The flow mechanisms that explain the behavior of the experimental sound pressure level(SPL) curve are described, and an improved setup is used to reproduce the flow structures that lead to the measured SPL.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.9 no.2
• /
• pp.146-146
• /
• 1995

본 논문은 유도전동기의 운전조작시에 발생되는 자계변화특성에 대하여 기술하였다. 본 측정시스템은 자기적분형 자계센서, 증폭기, 능동형 적분기로 이루어졌으며, 교정실험에 대한 측정계의 주파수대역과 감도는 각각 20[Hz]∼0.234[mV/μT]이다. 유도전동기의 기동과 정상운전중에 발생하는 자계성분을 측정하였으며, 고조파 성분을 고속 푸리에 변환기법으로 분석하였다. 유도전동기의 직입기동시에는 단일성 펄스자계가 강하게 발생하였으며, 이의 피크치는 정상상태의 값보다 5배이상 크게 나타났다. 이러한 긴 과도시간과 강한 자계의 세기는 전동기의 큰 인덕턴스와 동특성에 기인된다. 유도전동기의 정상운전시에는 유도전동기의 극수에 의존하는 기본파에 대한 분조파의 자계성분이 관측되었다. 또한, 자계의 분조파 성분은 전동기의 토크 변동으로 불균일한 회전토크로 인해 생기는 맥동전류와 전압플리커에 의해서 발생하는 것으로 생각된다. 인버터구동형 유도전동기에서는 직입기동에 비하여 많은 고조파 성분이 발생되고 있었으며, 특히 전동기의 구동주파수가 낮을수록 맥동토크에 의한 전류변화로 고조파 성분은 더욱 증가하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.15 no.2
• /
• pp.1-6
• /
• 2001

Tunnel lighting in Korea has the problems of unsatisfactory illuminance uniformity which obstructs driver's vision, a flicker phenomenon on wall of tunnel, a heavy glare, low efficiency of luminaires, low utilization factor, and high energy consumption. We developed a high efficiency luminaire reflector for tunnel lighting which removes these problems. Developed luminaire saves energy and improves lighting environment by increasing 10% of luminaire efficiency. It can reduce installation cost by decreasing the number of luminaires, while average illuminance of 200[lx], overall uniformity of 0.4, longitudinal uniformity of 0.7, and electric power consumptions per unit area of 3.7[W/m$^2$] are accomplished.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.14 no.4
• /
• pp.701-706
• /
• 2019

The advent of the AI(: Artificial Intelligence) has applied to many industrial and general applications have havingact on our lives these days. Various types of machine learning methods are supported in this field. The supervised learning method of the machine learning has features and targets as an input in the learning process. There are many supervised learning methods as well and their performance varies depends on the characteristics and states of the big data type as an input data. Therefore, in this paper, in order to compare the performance of the various supervised learning method with a specific big data set, the supervised learning methods supported in the Tensorflow and the Sckit-Learn are simulated and analyzed in the Jupyter Notebook environment with python.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2023.07a
• /
• pp.655-656
• /
• 2023

지구 환경 위기가 날이 갈수록 가시화되어가고 있다. 국가 차원의 노력에도 불구하고 지구의 온도는 지속해서 오르고 있고, 해수면 상승 속도 또한 가속화되고 있다. 환경 보호의 중요성은 과거에도 중요했지만, 최근 생태계와 기후의 변화가 급속도로 진행되면서 훨씬 더 무게를 가지게 되었다. 본 논문은 이러한 환경 위기를 극복하기 위해 플로깅 매칭 시스템, 환경 실천 인증 SNS, 환경 퀴즈 등 환경 보호에 도움을 주는 기능들을 집합시킨 친환경 커뮤니티 플랫폼으로 개발하였다. 또한 이러한 활동을 할 때마다 사용자들에게 포인트를 지급하여 애플리케이션을 꾸준히 사용하도록 유도한다. 이를 통해 친환경에 대한 관심을 고취하고 결과적으로는 사용자로 하여 환경 보호를 자발적으로 지속하는 상태로 만드는 것을 목표로 한다.

• Journal of Digital Convergence
• /
• v.12 no.1
• /
• pp.555-561
• /
• 2014

Artificial intelligence in the game is mainly used to determine patterns of behavior of NPC (Non Player Character) and the enemy, path finding. These artificial intelligence is implemented by FSM (Finite State Machine) or Flocking method. The number of NPC behavior in FSM method is limited by the number of FSM states. If the number of states is too small, then NPC player can know the behavior patterns easily. On the other hand, too many implementation cases make it complicated. The NPC behaviors in Flocking method are determined by the leader's decision. Therefore, players can know easily direction of movement patterns or attack pattern of NPCs. To overcome these problem, this paper proposes agonistic behaviors(attacks, threats, showing courtesy, avoidance, submission)in animals to apply for the NPC, and implements agonistic behaviors using Unity3D engine. This paper can help developing a real sense of the NPC artificial intelligence.

• Journal of the Korea Institute of Building Construction
• /
• v.20 no.4
• /
• pp.313-319
• /
• 2020

In this study, in order to confirm the applicability of Hollow Glass Powder(HGP) in 70MPa-class high strength concrete, the fresh and hardened states were examined according to the amount of HGP, and the results are as follows. The flow characteristics showed that the slump flow increased slightly as the amount of HGP was increased, and the T500 was slightly shortened as the amount of HGP was increased, and the rebar passing ability was improved due to the ball bearing effect of HGP. In particular, it showed the best rebar passing ability at a usage of 1.0kg/㎥. The use of HGP 1.0kg/㎥ resulted in a 40% reduction in plastic viscosity, but the viscosity increased at 2.0kg/㎥. Through experiments, it was confirmed that HGP was helpful in improving the workability of high-strength concrete, and the usage of 1.0kg/㎥ is considered to be the most appropriate. It was confirmed that HGP does not affect concrete compressive strength.

• Journal of the Korea Concrete Institute
• /
• v.26 no.1
• /
• pp.23-34
• /
• 2014

This study investigates the relationship between the performance of fresh and hardened Ultra-High Performance Concrete (UHPC) without heat treatment. The performance of fresh UHPC is determined by the slump flow test related to the fluidity of concrete mixtures, and the air content test. The variables of these tests are the water to binder ratio, superplasticizer dosages and volume fractions of steel fiber. Generally, insufficient fluidity and excessive air contents in concrete mixtures lead to the insufficient packing density related to the performance of harden concrete. The performance of hardened UHPC is determined by the compressive and flexural tensile tests. The results of the fresh UHPC tests show that there is the linear correlation between each variable and the slump flow diameter, and that the slump flow diameter is linearly decreased as the air content ratio increase. Using these results, the formula is developed to predict the fresh performance before mixing UHPC. The results of the hardened UHPC tests show that the hardened performance is not influenced by the air content ratio in the range of 3.2 to 4.2 per cent. However, the flexural tensile strength dominantly influenced by the volume fractions of steel fiber.

• The Journal of Society for e-Business Studies
• /
• v.15 no.4
• /
• pp.265-284
• /
• 2010

B2B e-commerce guarantee service is a guarantee service combining the electronic systems among Korea Credit Guarantee Fund(KCGF), banks and e-marketplaces to process all procedures on internet ranging from application for credit guarantee, issue of written guarantee and contracting for a commerce to payment. B2B e-commerce guarantee service plays as an intermediary role in financial support for small and mediumsized enterprise(SME), which are small size, low credit level, and unfavorable status in many aspects compared to major companies. Despite the B2B e-commerce guarantee service has various advantages conducive to promotion of e-commerce among small and medium businesses as well as development of e-commerce itself, it has yet to be diffused due to lack of acknowledgement, misunderstanding of its functions and vague psychological fear of the on-line settlement. Thus, this study identifies the values and effects of the B2B e-commerce guarantee service using financial data and cases. The process of this study is 4 phase. first phase is analysis of B2B e-commerce guarantee service and e-Marketplace. second phase is analysis of performance from the Perspective of Diverse Participants. third phase is analysis of economic performance and support for SME. last phase is policy suggestions and conclusion.