• Korean Journal of Agricultural and Forest Meteorology
• /
• v.16 no.1
• /
• pp.22-28
• /
• 2014

This study was conducted to investigate the photosynthetic characters of Populus alba${\times}$glandulosa cuttings in response to elevated $CO_2$ concentration and air temperature for selecting tree species adaptive to climate change. The cuttings were grown in environment controlled growth chambers with two combinations of $CO_2$ concentration and air temperature conditions: (i) $22^{\circ}C$ + $CO_2$ 380 ${\mu}mol$ $mol^{-1}$ (control) and (ii) $27^{\circ}C$ + $CO_2$ 770 ${\mu}mol$ $mol^{-1}$ (elevated) for almost three months. The cuttings under the elevated treatment showed reduced tree height and photosynthetic pigment contents such as chlorophyll and carotenoid. In particular, the elevated treatment resulted in a marked reduction in the chlorophyll a closely associated with $CO_2$ fixative reaction system. Different levels of reduction in photosynthetic characters were found under the elevated treatment. A decrease was noted in photochemical reaction system parameters: net apparent quantum yield (7%) and photosynthetic electron transport rate (14%). Moreover, a significant reduction was obvious in $CO_2$ fixative reaction system parameters: carboxylation efficiency (52%) and ribulose-1,5-bisphosphate(RuBP) regeneration rate (24%). These results suggest that the low level of photosynthetic capacity may be attributed to the decreased $CO_2$ fixative reaction system rather than photochemical reaction system.

• Journal of Life Science
• /
• v.34 no.3
• /
• pp.170-178
• /
• 2024

Adipose-derived stem cells (ADSCs) are capable of differentiation into multiple lineages of cells, which has attracted attention for clinical therapy. However, ADSCs have poor proliferation capacity and a short life span in culture, which is an impediment in the application to clinical use. Previously, to overcome growth disadvantages, we had established an immortalized ADSC line (ADSC-T) by introducing the SV40 T antigen coding gene into primary human ADSC. In the present study, we evaluated the differentiation potential of this cell line and assessed the anti-inflammatory effect of its conditioned medium (CM). ADSC-T appeared to maintain the differentiation potential into adipocyte and chondrocyte. The CM of ADSC-T suppressed the NF-κB activity and its target gene expression of COX-2 and iNOS. Furthermore, the phosphorylations of MAPKs, including ERK, JNK and p38, were suppressed by the ADSC-T CM. The expressions of pro-inflammatory cytokines such as TGF-β, TNF-α, IL-6, and IL-13 were also suppressed by the CM of ADSC-T. In the Nc/Nga atopic model mice, the CM showed therapeutic effect on DNCB-induced atopic dermatitis. These results indicate that the immortalized ADSC-T maintains the beneficial properties of primary ADSC and could be a versatile cell source for not only research into ADSC but also for production of CM suitable for clinical application.

• Journal of Satellite, Information and Communications
• /
• v.8 no.1
• /
• pp.1-7
• /
• 2013

Currently satellite communication systems usually use the ACM(Adaptive Coding and Modulation) to extend the link availability and to increase the bandwidth efficiency. However, when ACM system is used for satellite communications, we should carefully consider TCP congestion control to avoid network congestions. Because MODCODs in ACM are changed to make a packet more robust according to satellite wireless link conditions, bandwidth of satellite forward link is also changed. Whereas TCP has a severe problem to control the congestion window for the changed bandwidth, then packet overflow can be experienced at MAC or PHY interface buffers. This is a reason that TCP in transport layer does not recognize a change of bandwidth capability form MAC or PHY layer. To overcome this problem, we propose the adaptive congestion control scheme of TCP for supporting ACM in Satellite PEP (Performance Enhancing Proxy) systems. Simulation results by using ns-2 show that our proposed scheme can be efficiently adapted to the changed bandwidth and TCP congestion window size, and can be useful to improve TCP performance.

• Electronics and Telecommunications Trends
• /
• v.20 no.1 s.91
• /
• pp.139-146
• /
• 2005

폭발적인 정보의 흐름 속에 놓여 있는 지식정보화 시대에서는 필요한 정보를 선택하고 가공하여 새로운지식의 창조, 전달 및 확대 재생산 할 수 있는 능력이 요구되고 있다. 지식정보화 시대가 필요로 하는 창의적 인재 육성을 위한 새로운 교육 형태와 패러다임으로 e-러닝이 유력한 솔루션으로 부각되고 있다.e-러닝은 교수자 중심의 일방향 교육이 아닌 학습자가 시간과 장소에 구애받지 않고 필요한 학습을 하는 양방향 교육 방식이나, 현재까지는 학습 콘텐츠의 단순 반복 학습에 그치고 있어 기존 교실 수업 방식에 비해 학습효율이 떨어지는 점이 이 분야 발전의 장애요소가 되고 있다. 이에 대한 해결책으로 온라인상에서 학습 과제를 여러 명의 학생들이 상호 의존하여 공동으로 해결함으로써 학습 목표를 달성하는 형태의 협력 학습에 대한 연구가 활발히 진행되고 있다. e-러닝 협력학습에는 단순히 학생들을 그룹화하여 함께 학습하도록 하는 것은 교육 효과면 에서 비효율적일 수 있으며, 학생들의 자발적인 참여와 협력을 유도할 수 있는 교수모형을 적용하여야 하며, 개인의 책임감을 근간으로 한 상호 의존적 과제 해결 활동이 이루어져야 한다. 본 고에서는 협력 e-러닝 학습을 위한 연구사례와 기술 동향들에 대해 살펴본다.

• Journal of Digital Convergence
• /
• v.10 no.1
• /
• pp.67-75
• /
• 2012

In the knowledge-based society, utilization of women's resources has significant implications as the key to success of national competitiveness. The space and conditions for women to show their abilities in all areas should be provided. Policies on women's resources, which aim to achieve gender equality, should not be limited to the area of social welfare as usual, but should be treated in-depth with relation to political, economic, social, and cultural areas. Local women policies do not reflect the distinct characteristics of the local areas and realities of women, furthermore, even the concept of women policies is not delivered to local women. In this study, directions to shift local women policies from the marginalization to the mainstream of policy are discussed focusing on utilization of women's resources.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.9 no.6
• /
• pp.553-559
• /
• 2004

The servo motor is used for the driving power source of the conventional linear conveyor system. The mechanical power transfer system is needed for converting the circular to the linear operation. But this system causes some problems of position error, the necessity of the periodical maintenance. In this paper the study on application of transverse flux linear motor(TFLM) is carried out for the indexer system of LCD processing because TFLM has much thrust per a volume than the conventional motor. TFLM is suitable system for the indexer system because of capacity of acceleration, maximum speed and precision of the position, etc.

• Journal of Life Science
• /
• v.21 no.6
• /
• pp.865-874
• /
• 2011

The genus Bryophyllum is best known for many of its species having the ability to produce plantlets on their leaves. This phenomenon is also known as vegetative reproduction. Differential expressed gene (DEG) detecting technique was applied in order to survey the genes involved in the process of asexual reproduction for plantlet formation. Based on homology search using the NCBI database after screening of genes, 38 genes were identified from a total of 69 DEGs. Most of these DEGs were related to cell division, to intercellular signal transduction, and to hormone (cytokinin and ethylene) signaling.

• 한국벤처창업학회:학술대회논문집
• /
• 2019.04a
• /
• pp.143-148
• /
• 2019

시대적 변화에 따른 경력성공의 관점이 변화하고 있지만 다수의 연구들은 창업과 취업을 분리하여 연구되어 왔다. 또한 환경의 변화뿐만 아니라 개인 가치관의 변화에 따라 평생 직장의 개념이 사라졌으며 전 생애에 걸친 학습의 필요성이 대두 되고 있다. 학습의 형태는 기존의 지식을 전달하는 형태에서 다양하게 변화해왔다. 교실 수업의 형태는 팀활동과 미디어 활용을 중심으로 변화하고 있으며 교실 밖 수업에서는 자율적인 동아리 활동이나 커뮤니티의 참여 등을 통해 역량을 향상시키는 기회를 제공하고 있다. 개인의 경력은 인생에 걸친 학습과 일에 관련된 경험 및 행동과 연관된 태도로부터 발생한다. 이러한 경력을 이끌어가는 태도는 새로운 환경속에서 즉각적인 요구를 받아들이는 적응학습과 새로운 행동 및 지식을 유발하는 생성학습, 그리고 상호작용 패턴 인식을 통해 새로운 시도를 하는 전환학습을 지속적으로 일으킨다. 또한 이러한 무형식 학습들은 취업과 연계 될 뿐만 아니라 창업의도에도 긍정적인 영향을 줄 수 있다. 본 연구는 자기주도성과 가치지향성을 척도로 하는 프론티언 경력태도가 창업의도에 영향을 미치지 확인함으로서 기존의 취업역량과 연결시켜왔던 연구에 새로운 시사점을 제시하고자 한다. 또한 무형식학습 활동을 매개변인으로 투입하여 학습 과정에서 자연스럽게 발생하는 학습의 효과를 확인하여 변화된 교육형태의 중요성을 확인하는데 의의가 있다. 이에 더해 스마트미디어를 활용하는 능력인 스마트미디어 리터러시와 팀 학습을 지향하는 팀학습 선호도를 조절효과로 보아 분석함으로서 스마트미디어활용 학습과 팀학습의 형태로 변화하고 있는 교육 현장의 특성을 함께 확인하고자 한다. 이를 위해 2019년 3월부터 6월까지 교육과 경력 환경의 변화의 중심에 서있는 대학생들을 대상으로 설문조사를 실시하여 이를 분석하고자 한다.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.35 no.5
• /
• pp.469-475
• /
• 2002

The rotating biological contactor (RBC) was tested for treatment of aquacultural water in a pilot-scale recirculating aquaculture system. Performance of RBC on the treatment of nitrogen source such as total ammonia nitrogen (TAN), nitrite nitrogen and nitrate nitrogen and chemical oxygen demand (CODcr.) was evaluated. A system was stocked with nile tilapia at an initial rearing densities of $5\%$ and $7\%$ over 30 days. As increasing rearing density from $5\%$ to $7\%$, the TAN removal rates was increased from $39.4 g/m^3{\cdot}day$ to $86.0 g/m^3{\cdot}day$. But TAN removal efficiency was decreased from $24.5\%$ to $16.0\%$. The removal rate of $COD_Cr$ was higher than TAN. The RBC as an aerator was also evaluated for increasing dissolved oxygen concentration. For $5\%$ and $7\%$ of rearing density, the average aeration rate were $280 g/m^3{\cdot}day$ and $255 g/m^3{\cdot}day$, respectively.

• Journal of the Korean earth science society
• /
• v.26 no.1
• /
• pp.1-8
• /
• 2005

The purpose of this study is to identify the effect of Problem-Based Learning on Student's Creativity Ability in Middle School Science Class. The experimental group had Problem-Based Learning classes for six weeks and control group had traditional inquiry instruction for the same period. The results of this study presents that Problem-Based Learning is significantly effective for the improvement of creative skills test and creative tendencies. And PBL group student's had positive thinking for PBL. It's not easy to generalize these results because of many different variables. but the results suggests that teachers should make an effort to improve student's creativity applying Problem-Based Learning. And it's necessary to develop many kinds of problems and teacher's instruction method to enrich creativity in the process of Problem-Based Learning.