95,928 research outputs found
Geun-Soo Kim
No full text학위논문(석사)--아주대학교 일반대학원 :산업공학과,2019. 2탄성 광 네트워크는 상향과 하향이 대칭 구조인 상태로 연구가 진행되어왔다. 하지만 현재의 트래픽 특성은 클라우드 컴퓨팅, AI, 빅데이터, IoT 등의 서비스 개발로 인해 비대칭 특성을 보이고 있으며, 앞으로 이러한 특성은 점점 더 심화될 예정이다.
본 논문에서는 인터넷 트래픽의 비대칭 특성을 수용하기 위해 MF-OTP(Multi-Flow Optical Transponder) 기반의 유연한 노드 아키텍처를 제안한다.
제안 된 MF-OTP 아키텍처는 다음 두 가지 측면에서 유연하다. 첫째, 트래픽 수요에 따라 서브채널을 하향 또는 상향 트래픽을 전송하도록 유연하게 조정할 수 있다. 둘째, 유연한 변조 레벨을 사용하여 동일한 트래픽 요구를 제공하는 다수의 서브 채널을 허용한다.
비대칭 트래픽을 처리 할 때 유연한 MT-OTP의 효율성을 평가하기 위해 세 개의 정수형 선형 프로그래밍(ILP) 모델을 제안한다. 첫 번째 모델은 필요한 서브 채널 수를 최소화하는 것을 목표로 하며, 두 번째 모델은 트래픽 전송량을 최대화하는 것을 목표로 한다. 마지막 모델은 서브 채널의 수와 네트워크 전력 소비의 최적 조합을 찾는 것을 목표로 한다.
시뮬레이션을 수행 한 결과는 유연한 MF-OTP 아키텍처를 기반으로 한 제안 된 모델이 더 적은 수의 서브 채널을 필요로 하고 더 많은 트래픽 수요를 제공 할 수 있음을 보여주며, 네트워크 상황에 따른 최적의 조합을 찾는 것을 보여준다.제 1 장 서 론 1
1 절 연구의 필요성 및 목적 1
2 절 연구의 범위 및 구성 2
제 2 장 관련 연구 3
1 절 탄성 광 네트워크 3
2 절 비대칭 트래픽 5
3 절 라우팅/변조/대역할당 모형 6
4 절 소프트웨어 정의 네트워크 7
제 3 장 MF-OTP 기반 탄성 광 네트워크 설계 9
1 절 MF-OTP 제안 9
1.1 기존 MF-OTP 9
1.2 유연한 MF-OTP 10
1.3 기존/유연한 MF-OTP 비교 11
2 절 유연한 서브 채널 제안 13
3 절 전력 소비 모델 제안 15
제 4 장 라우팅/변조/대역할당 모형 설계 16
1 절 정수형 선형 프로그래밍 모델 제안 16
1.1 파라미터 소개 17
1.2 변수 소개 18
1.3 제약 조건 소개 19
1.4 추가 변수 및 추가 제약 조건 소개 24
1.5 목적식 소개 26
2 절 실험 가정 및 설정 27
3 절 실험 결과 28
제 5 장 결론 및 향후 연구 34
참고문헌 36
Abstract 39MasterElastic optical networks have been studied with symmetrical structures upstream and downstream. However, current traffic characteristics are asymmetric due to cloud computing, AI, big data, and IoT. These characteristics are expected to become more and more intense.
In this paper, we propose a flexible node architecture based on MF-OTP in an EONs to accommodate the asymmetric characteristics of Internet traffic. The proposed MF-OTP architecture is flexible in the following two degrees. Firstly, it can be flexibly adjusted to transmit either downstream or upstream traffic according to the timely traffic demand distribution. Secondly, it allows multiple sub-channels using flexible modulation formats to serve the same traffic demand.
We propose three ILP models to evaluate the efficiency of flexible MF-OTP when dealing with asymmetric traffic. One is aimed at minimizing the number of sub-channels required, and the other is aiming to maximize the traffic volume. The last model goal is to find the optimal combination of the number of sub-channels and network power consumption.
Simulations show that the proposed model based on the flexible MF-OTP architecture requires fewer sub-channels and can provide more traffic demand. And, it shows the optimal combination according to the network situation
Effects of water level and soil type on the survival and growth of Persicaria thunbergii during early growth stages
No full textWe investigate the effects of water level and soil type on the survival and growth of Persicaria thunbergii during the recruitment phase. Plants in four early growth stages (uprooted seed, seedling with cotyledon, seedlings with two and four foliage leaves) were planted under combined conditions of six water levels (dry, wet, flooding) and two soil types (loamy sand, sand). Six weeks later, the survival rates, plant heights and biomass were measured. The uprooted seeds survived under water levels lower than 6 cm. The seedlings in other growth stages could not overcome water levels twice their height. Under dry conditions, the plant height and biomass were higher in sand than in loamy sand, yet under saturated conditions, the opposite result was obtained. The water level relative to seedling height was the most critical factor for early survival, and seedling growth was also affected by soil type. Thus, P. thunbergii in constructed wetlands can be removed during the seedling recruitment phase using water level regulation. (C) 2013 Elsevier B.V. All rights reserved.N
Spike Proteins of SARS-CoV-2 Induce Pathological Changes in Molecular Delivery and Metabolic Function in the Brain Endothelial Cells
No full textSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes the coronavirus disease (COVID-19), is currently infecting millions of people worldwide and is causing drastic changes in people’s lives. Recent studies have shown that neurological symptoms are a major issue for people infected with SARS-CoV-2. However, the mechanism through which the pathological effects emerge is still unclear. Brain endothelial cells (ECs), one of the components of the blood–brain barrier, are a major hurdle for the entry of pathogenic or infectious agents into the brain. They strongly express angiotensin converting enzyme 2 (ACE2) for its normal physiological function, which is also well-known to be an opportunistic receptor for SARS-CoV-2 spike protein, facilitating their entry into host cells. First, we identified rapid internalization of the receptor-binding domain (RBD) S1 domain (S1) and active trimer (Trimer) of SARS-CoV-2 spike protein through ACE2 in brain ECs. Moreover, internalized S1 increased Rab5, an early endosomal marker while Trimer decreased Rab5 in the brain ECs. Similarly, the permeability of transferrin and dextran was increased in S1 treatment but decreased in Trimer, respectively. Furthermore, S1 and Trimer both induced mitochondrial damage including functional deficits in mitochondrial respiration. Overall, this study shows that SARS-CoV-2 itself has toxic effects on the brain ECs including defective molecular delivery and metabolic function, suggesting a potential pathological mechanism to induce neurological signs in the brain
Sang-Do Paul Kim interview
No full textWichita, Kansas, United StatesSang-Do Paul Kim was born in Wichita, Kansas. His Korean parents were the first generation to come to America, making Kim the first child out of his immediate and extended family to be born in this country. He grew up on college campuses with his father having a PhD in Aerospace Engineering. Due to Korean cultural differences, Paul did not feel like he had a voice in his family growing up. He discovered a love for free-style rap when he first moved to Washington, where he did not have any friends yet. Although this rap hobby was unsupported by his parents, Paul started entering rap battles - and doing well at them. This passion for artistic expression and music led Paul to help start the University of Washington Bothell's very first radio station called UWave radio. Kim discusses his role in starting the station, all the ins and outs of operating community radio, potential content, locations, legal issues, licensing, and the inside scoop on committee meetings
The optimal balance between sexual and asexual reproduction in variable environments: a systematic review
No full textThis article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made.Abstract
Many plant species have two modes of reproduction: sexual and asexual. Both modes of reproduction have often been viewed as adaptations to temporally or spatially variable environments. The plant should adjust partitioning to match changes in the estimated success of the two reproductive modes. Perennial plants showed that favorable habitats in soil nutrients or water content tend to promote clonal growth over sexual reproduction. In contrast, under high light-quantity conditions, clonal plants tend to allocate more biomass to sexual reproduction and less to clonal propagation. On the other hand, plants with chasmogamous and cleistogamous flowers provides with a greater tendency of the opportunity to ensure some seed set in any stressful environmental conditions such as low light, low soil nutrients, or low soil moisture. It is considered that vegetative reproduction has high competitive ability and is the major means to expand established population of perennial plants, whereas cleistogamous reproduction is insurance to persist in stressful sites due to being strong. Chasmogamous reproduction mainly enhances established and new population. Therefore, the functions of sexual and asexual propagules of perennial or annual plants differ from each other. These traits of propagule thus determine its success at a particular region of any environmental gradients. Eventually, if environmental resources or stress levels change in either space or time, species composition will probably also change. The reason based on which the plants differ with respect to favored reproduction modes in each environmental condition, may be involved in their specific realized niche
Establishment strategy of a rare wetland species sparganium erectum in Korea
No full textBackground: To reveal establishment strategy of Sparganium erectum, we tried to find realized niche of adults through field survey and effects of water level on the establishment process through mesocosm experiments. Results: In the field survey, the height and coverage of community living in deeper water were greater than those of community living in shallow water. There was no statistically significant difference (p > 0.05) in the means of water and soil properties between the two communities. In mesocosm experiments, we found no correlation between water levels and germination rates, but S. erectum seedlings have characteristics of post germination seedling buoyancy when S. erectum seeds germinated in inundation conditions. Shoot height, total leaf length, and survival rates of sinking seedlings in shallow water levels at −5, 0, and 5 cm were higher than those in deeper water levels at 10 and 20 cm. Floating seedlings established in water levels of 3 and 6 cm only. The seedlings could live up to 6 weeks in floating state but died if they were unable to establish. Conclusions: The water level around adult S. erectum communities in the field were different from the water level at which S. erectum seedlings can survive in the mesocosm experiments. The findings provided not only understanding of S. erectum habitat characteristics but also evidence to connect historical links between the early seedlings stage and adult habitat conditions. We suggested the logical establishment strategy of S. erectum based on the data. © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License.OAIID:RECH_ACHV_DSTSH_NO:T201711989RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A075900CITE_RATE:0DEPT_NM:생물교육과EMAIL:[email protected]_YN:YN
Molecular evolution of a novel bifunctional D-hydantoinase/N-carbamylase fusion enzyme for functional expression with enhanced stability
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