• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.24.2-24
• /
• 2001

In this paper, the authors present a row dynamic route planning by Q-learning. The proposed algorithm is executed in a cellular automation based traffic simulator, which is also newly created. In Vehicle Information and Communication System(VICS), which is an active field of Intelligent Transport System(ITS), information of traffic congestion is sent to each vehicle at real time. However, a centralized navigation system is not realistic to guide millions of vehicles in a megalopolis. Autonomous distributed systems should be more flexible and scalable, and also have a chance to focus on each vehicles demand. In such systems, each vehicle can search an own optimal route. We employ Q-learning of the reinforcement learning method to search an optimal or sub-optimal route, in which route drivers can avoid traffic congestions. We find some applications of the reinforcement learning in the "static" environment, but there are ...

• 한국결정성장학회지
• /
• 제7권4호
• /
• pp.560-566
• /
• 1997

Seeded vapor transport법에 의해 성장된 ZnSe 결정내에서 전위거동을 살펴보았다. (111)과 (100) ZnSe wafer의 etch pit 형상을 관찰하였고 성장된 결정이 높은 전위밀도를 가지면 전위들이 lineage와 cellular 두 가지 형태로 배열됨을 알았다. Seed로부터 측방성장된 부위에서 전위밀도의 변화는 없었으나 수직 성장방향으로는 전위밀도가 감소하였고, 같은 wafer내에서 전위밀도는 wafer center 지역의 전위밀도가 edge부위의 전위밀도 보다 낮았다. 성장된 결정의 평균 전위밀도는 $4{\times}10^4 /\textrm{cm}^2$이었다.

• 한국ITS학회 논문지
• /
• 제8권2호
• /
• pp.100-107
• /
• 2009

이동 셀룰라 시스템에서 단말의 속도를 알아내는 것은 효율적인 시스템 운영을 위해 꼭 필요한 일이다. 그동안 여러 가지 이동체의 속도 추정 방안이 제안되어 왔는데, 이 논문에서는 적응형 어레이 안테나를 이용해 간단하게 속도를 추정하는 방안을 제안한다. 제안하는 방안은 이동체의 속도를 이동 거리 정보와 상주시간 정보를 이용해 추정한다. 이 방안은 추가적인 코스트 부담 없이 정확하게 속도를 추정할 수 있다. 제안하는 방안의 성능 분석을 위해 본 논문에서는 수학적 분석과 시뮬레이션을 수행하였고 그 결과 제안하는 방안이 만족할만한 성능을 보여주는 것을 알 수 있었다.

• 한국ITS학회 논문지
• /
• 제10권5호
• /
• pp.87-92
• /
• 2011

본 논문에서는 800 ~ 900 MHz 주파수 대역에서 러시아 PNG 지역에 오쿠무라-하타 모델을 적용하여 경로 손실식을 구하였다. 기존의 경로 손실 모델을 이용하여 러시아 PNG 지역의 새로운 경로 손실 특성식을 구하기 위해서, 최소 자승 평균 기법을 적용하여 기존 모델에 대한 수정치를 구하였다. 자유 공간 및 하타 모델과 측정치의 수정치가 28, 13 dB 임을 알 수 있었으며, 이 값을 적용하여 러시아 PNG 지역에 맞는 새로운 경로손실 모델을 제시하였다.

• Advances in biomechanics and applications
• /
• 제1권4호
• /
• pp.227-237
• /
• 2014

The in vitro construction of osteo-articular large implants combining biomaterials and cells is of great interest since these tissues have limited regeneration capability. But the development of such organoids is particularly challenging, especially in the later time of the culture, when the extracellular matrix has almost filled the initial porous network. The fluid flow needed to efficiently perfuse the sample can then not be achieved using only the hydraulic driving force. In this paper, we investigate the interest of using an electric field to promote mass transport through the scaffold at the late stage of the culture. Based on the resolution of the electrokinetics equations, this study provides an estimation of the necessary electric driving force to reach a sufficient oxygen perfusion through the sample, thus analyzing the feasibility of this concept. The possible consequences of such electric fields on cellular activities are then discussed.

• BMB Reports
• /
• 제50권4호
• /
• pp.164-174
• /
• 2017

Mitochondria are cytosolic organelles essential for generating energy and maintaining cell homeostasis. Despite their critical function, the handful of proteins expressed by the mitochondrial genome is insufficient to maintain mitochondrial structure or activity. Accordingly, mitochondrial metabolism is fully dependent on factors encoded by the nuclear DNA, including many proteins synthesized in the cytosol and imported into mitochondria via established mechanisms. However, there is growing evidence that mammalian mitochondria can also import cytosolic noncoding RNA via poorly understood processes. Here, we summarize our knowledge of mitochondrial RNA, discuss recent progress in understanding the molecular mechanisms and functional impact of RNA import into mitochondria, and identify rising challenges and opportunities in this rapidly evolving field.

• Molecules and Cells
• /
• 제37권8호
• /
• pp.575-584
• /
• 2014

Potassium is a macronutrient that is crucial for healthy plant growth. Potassium availability, however, is often limited in agricultural fields and thus crop yields and quality are reduced. Therefore, improving the efficiency of potassium uptake and transport, as well as its utilization, in plants is important for agricultural sustainability. This review summarizes the current knowledge on the molecular mechanisms involved in potassium uptake and transport in plants, and the molecular response of plants to different levels of potassium availability. Based on this information, four strategies for improving potassium use efficiency in plants are proposed; 1) increased root volume, 2) increasing efficiency of potassium uptake from the soil and translocation in planta, 3) increasing mobility of potassium in soil, and 4) molecular breeding new varieties with greater potassium efficiency through marker assisted selection which will require identification and utilization of potassium associated quantitative trait loci.

• 대한약리학회지
• /
• 제5권1호
• /
• pp.29-33
• /
• 1969

The effects of Ginseng saponin on respiration and $Na^+$, $K^+$ content of rat cerebral cortex slices were investigated to determine the action of Ginseng saponin on brain cortex at cellular level. There are many reports for the study of Ginseng on central stimulatory action in experimental animals. The electrical stimulation of slices of cortex causes a loss of potassium. And the respiration is needed to maintain a supply of energy for active cation transport. The reduction in $Qo_2$ is a consequence of primary cessation of active cation transport. Ginseng saponin stimulated respiration which was depressed by Morphine. But there was no significant change of electrolyte. It is suggested that the Ginseng saponin act rather on metabolic process than neural excitatory mechanism in vitro.

• Preventive Nutrition and Food Science
• /
• 제1권1호
• /
• pp.143-150
• /
• 1996

The membrane fatty acid composition of tumor cell can be modified either in cell by altering the lipid composition of the medium of during growth in animals by changing the dietaty fat composition. These modifications are associated with changes in membrane physical properties and certain cellular functions, including carrier-mediated transport and enzyme contained within the membrane. Such effects influence the transport of nutrients and chemotherapeutic agents in cancer cells .Fatty acid modification also can enhance the sensitivity of the neoplastic cell to chemotherapy. The alteration in plasma membrane composition will be affected through dietary supplementations and the potential value to cancer patients could be a better understanding of the effects of diet on responsiveness of neoplasms to chemotherapy, i.e. cancer patients' chances for a "cure" can be improved by diet changes prior to treatment.

• 대한핵의학회:학술대회논문집
• /
• 대한핵의학회 2001년도 제40차 춘계학술대회 및 연수교육
• /
• pp.66-75
• /
• 2001

Although diverse mechanisms are involved in multidrug resistance for chemotherapeutic drugs, the development of cellular P-glycoprotein(Pgp) and multidrug-resistance associated protein (MRP) are important factors in the chemotherapy failure to cancer. Various detection assays provide information about the presence of drug efflux pumps at the mRNA and protein levels. However these methods do not yield information about dynamic function of Pgp and MRP un vivo. Single photon emission tomography (SPECT) and positron emission tomography (PET) are available for the detection of Pgp and MRP-mediated transport. $^{99m}Tc$-sestaMIBl and other $^{99m}Tc$-radiopharmaceuticals are substrates for Pgp and MRP, and have been used in clinical studies for tumor imaging, and to visualize blockade of Pgp-mediated transport after modulation of Pgp pump. Colchicine, verapamil and daunorubicin labeled with $^{11}C$ have been evaluated for the quantification of Pgp-mediated transport with PET in vivo and reported to be feasible substrates with which to image Pgp function in tumors. Leukotrienes are specific substrates for MRP and N-$[^{11}C]$acetyl-leukotriene E4 provides an opportunity to study MRP function non-invasively in vivo. Results obtained from recent publications are reviewed to confirm the feasibility of using SPECT and PET to study the functionality of MDR transporters in vivo.