인구구조 변화에 따른 대학의 미래

이영호,Lee, Yeong-Ho 한국대학교육협의회 2004 大學敎育 Vol.131 No.-

대학의 위기는 대학진학 인구의 감소가 가져온 위기 외에도 교육기능 뿐만 아니라 새로운 지식창출을 통한 국가 경쟁력 강화의 견인차가 되어 줄 것을 요구받고 있으며, 대학인들의 적극적인 사회봉사와 참여를 통한 건전한 시민사회 형성에도 그 책임을 다해줄 것을 요구받고 있다.

급냉응고한 Al-Zn-Mg-Zr합금의 시효거동과 인장특성에 미치는 Mn의 영향

이영호,장준연,유재은,문인기,맹선재,최종술,Lee, Yeong-Ho,Jang, Jun-Yeon,Yu, Jae-Eun,Mun, In-Gi,Maeng, Seon-Jae,Choe, Jong-Sul 한국재료학회 1997 한국재료학회지 Vol.7 No.1

급냉응고법을 이용하여 고용한도 이상으로 Mn량을 첨가할 때 Mn량에 따른 인장특성의 변화와 시효특성을 조사하였다. 원심분무법으로 AI-4.7%Zn-2.5%Mg-0.2%Zr합금에 Mn량을 각기 달리 첨가한 급냉응고 분말을 제조 하였다. 이 분말을 냉간압축, 진공 탈가스처리를 한 후 15:1로 압출하여 봉상 시편을 만들었다. 분말의 미세조직은 $\alpha$-AI수지상과 수지상간 편석부로 이루어져 있으며 Mn첨가에 따라 조직의 변화는 관찰되지 않았다. 빠른 냉각속도로 인하여 2.0%Mn을 첨가한 경우에도 초정 Mn상을 발견할 수 없었다. 압출재의 미세조직은 아결정립으로 이루어져 있으며 약간의 제2상들이 관찰되었다. 대부분의 Mn 분산상은 압출후 용체화처리 과정에서 형성되었으며 시효경화량은 Mn양에 관계없이 일정하였다. 46$0^{\circ}C$에서 1시간 용체화처리하고 12$0^{\circ}C$에서 24시간 시효처리한 경우 최대의 시효경도값을 나타내었다. 인장강도는 Mn첨가량에 따라 증가 하였는데 이것은 Mn분산상의 밀도증가에 의한 것으로 확인되었다. 2.0%Mn을 첨가한 합금의 시효후 인장강도는 590MPa, 연산율은 4%를 보였다.

ePRO-OMP: OpenMP 응용 프로그램의 성능 및 에너지 분석 도구

이영호,김지홍,Lee, Young-Ho,Kim, Jihong 대한임베디드공학회 2011 대한임베디드공학회논문지 Vol.6 No.5

As chip multiprocessors have been widely adopted in embedded systems, achieving both high performance and low power consumptions of parallel applications becomes challenging. In order to meet these requirements, it is crucial for developers to analyze the performance and energy consumption of parallel applications. In this paper, we propose a tool for profiling and optimizing the performance and energy consumption of OpenMP applications (energy PROfiler and analyzer for OpenMP: ePRO-OMP). The main advantage of ePRO-OMP is that it can analyze both the performance and energy consumption of each parallel region of an OpenMP application, which can help developers find the bottleneck of parallel applications in detail.

2차원 정방형 캐비티유동장의 비정상특성

이영호,최장운,도덕희,Lee, Y.H.,Choi, J.W.,Doh, D.H. 대한설비공학회 1995 설비공학 논문집 Vol.7 No.4

The present numerical study is aimed to investigate time-dependent characteristics of a two-dimensional lid-driven square cavity flow of three high Reynolds numbers, $7.5{\times}10^3$, $10^4$ and $3{\times}10^4$. A conservative convection term on irregular grids was adopted by renewing the MAC type difference schemes on regular grids. Relaxation of velocity and pressure is implemented by SOLA algorithm. In case of $Re=7.5{\times}10^3$, flow behavior converges to steady state after a transient period. But for $Re=10^4$, periodic unsteady sinusoidal fluctuation of local velocity and kinetic energy is found and continuous movements of small eddies in the secondary flow regions are also discovered. Random generation of eddies and their active migrating behavior are detected for $Re=3{\times}10^4$, resulting in complete unsteady and non-linear flow characteristics. And, an organized structure similar to a Moffat vortex is also observed from the time-mean flow patterns. Furthermore, a typoon-like vortex(TLV) appears intemittently and rotates along the separation regions and boundary layers.

세계화 시대의 고등교육 품질 보증과 대학평가의 국제 동향

이영호,Lee, Yeong-Ho 한국대학교육협의회 2008 大學敎育 Vol.153 No.-

환경기계 분야 연구동향

이영호,Lee, Yeong-Ho 한국유체기계학회 2011 한국유체기계학회 논문집 Vol.19 No.6

Particle Swarm Optimization을 이용한 2차원 IIR 디지털필터의 설계

이영호,Lee, Young-Ho 한국정보통신학회 2009 한국정보통신학회논문지 Vol.13 No.7

본 논문은 Particle Swarm Optimization(PSO)을 이용하여 2차원 IIR 디지털필터의 설계방법을 제안하였다. 먼저 2차원 디지털필터의 설계문제를 PSO에 적용하기 위하여 최소화 문제로써 형식화 과정이 논의된다. 제안된 PSO 알고리즘을 이용한 설계방법은 기존의 PSO 알고리즘에 IIR 필터설계에서 요구되는 안정성을 보증하는 과정이 검토되어 개선된다. 본 논문에서 제안된 방법의 타당성을 설계예시를 통해 고찰한 결과, 설계된 디지털필터는 동일한 설계사양으로 기존의 설계방법으로 설계된 디지털필터보다 근사오차 면에서 우수한 결과를 얻을 수 있었다. 또한 제안한 설계방법에 의한 2차원 IIR 디지털필터는 설계과정에서 필터의 안정성을 보증할 수 있었다. This paper presents an efficient design method of 2-D infinite impulse response(IIR) digital filter based on a particle swarm optimization(PSO) algorithm. The design task is reformulated as a constrained minimization problem and is solved by our newly developed PSO algorithm. To ensure the stability of the designed 2-D IIR digital filters, a new stability strategy is embedded in the basic PSO algorithm. The superiority of the proposed method is demonstrated by several experiments. The results show that the approximation error of the resultant filters are better than those of the digital filters which designed by recently published filter design methods. The proposed design method can also obtain the stable2-D IIR digital filters.

유니티 ML-Agents를 이용한 강화 학습 기반의 지능형 에이전트 구현

이영호,Young-Ho Lee 한국인터넷방송통신학회 2024 한국인터넷방송통신학회 논문지 Vol.24 No.2

The purpose of this study is to implement an agent that intelligently performs tracking and movement through reinforcement learning using the Unity and ML-Agents. In this study, we conducted an experiment to compare the learning performance between training one agent in a single learning simulation environment and parallel training of several agents simultaneously in a multi-learning simulation environment. From the experimental results, we could be confirmed that the parallel training method is about 4.9 times faster than the single training method in terms of learning speed, and more stable and effective learning occurs in terms of learning stability.

생체 리듬과 음식 섭취

이영호,Lee, Young-Ho 대한수면의학회 1998 수면·정신생리 Vol.5 No.1

Living organisms are influenced by many external rhythms and they have adapted their physiology to periodically changing conditions. These adaptive strategies are controlled by endogenous innate programs of behavior and physiology which are determined by external signals ("Zeitgeber"). There are many biological rhythms, each with its own characteristic functional adaptation. Among them, the presence of endogenous time control of feeding and drinking becomes obvious. There are increasing evidences that the control of food intake, food selection, and drinking are regulated by the endogenous rhythms including a circadian rhythm. However, there have been many restrictions in understanding the endogenous control of food intake itself and its mechanism. To broaden our know ledges of the endogenous time control of feeding and drinking, the author reviwed the characteristics of the endogenous timing for food intake, the influence of circadian pacemakers and food-entrainable oscillators, the interaction between the circadian control and the external and internal conditions in the control of food intake, the conseqences of feeding, the circadian control of food selection, and the biological cycles in energy balance.

마이크로 디퓨저 내의 양 방향 동적 유동과 펌프 구동 주파수에 따른 유동정류 특성 연구

이영호,강태구,조영호,Lee, Yeong-Ho,Gang, Tae-Gu,Jo, Yeong-Ho 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.2

This paper characterizes hi-directionally oscillating flow in planar microdiffusers in order to evaluate the frequency-dependent flow rectification performance of the microdiffusers. In the theoretical study, we analyze a hi-directionally oscillating flow in the planar microdiffuser. In the experimental study, we fabricate two different microdiffuser prototypes, having different neck widths of 100 ㎛ (D100) and 300 ㎛(D300), respectively. The experimental net flow rates are measured as 116.6 $\mu$ι/min. and 344.4 $\mu$ι/min. for D100 and D300, respectively. The experimental flow rate of D300 decreases at the oscillating flow frequencies higher than 90Hz, at which the net boundary layer thickness is reduced to the microdiffuser neck width. It is experimentally verified that the flow rectification performance and the net flow rate of the microdiffusers tend to decrease when the boundary layer thickness is smaller than the diffuser neck width.