Maximum Node Interconnection by a Given Sum of Euclidean Edge Lengths

Kim, Joonmo,Oh, Jaewon,Kim, Minkwon,Kim, Yeonsoo,Lee, Jeongeun,Han, Sohee,Hwang, Byungyeon The Korea Institute of Information and Commucation 2019 Journal of information and communication convergen Vol.17 No.4

This paper proposes a solution to the problem of finding a subgraph for a given instance of many terminals on a Euclidean plane. The subgraph is a tree, whose nodes represent the chosen terminals from the problem instance, and whose edges are line segments that connect two corresponding terminals. The tree is required to have the maximum number of nodes while the length is limited and is not sufficient to interconnect all the given terminals. The problem is shown to be NP-hard, and therefore a genetic algorithm is designed as an efficient practical approach. The method is suitable to various probable applications in layout optimization in areas such as communication network construction, industrial construction, and a variety of machine and electronics design problems. The proposed heuristic can be used as a general-purpose practical solver to reduce industrial costs by determining feasible interconnections among many types of components over different types of physical planes.

Fabrication of Electrochromic Devices Using Double Layer Conducting Polymers for Infrared Transmittance Control

Kim, Jin Kyu,Koh, Jong Kwan,Kim, Bumsoo,Jeon, Seokwoo,Ahn, Joonmo,Kim, Jong Hak Korean Society of Photoscience 2014 Rapid communication in photoscience Vol.3 No.2

We report the performance improvement of electrochromic devices for modulating the transmittance contrast of long wavelength infrared light between 1.5 and 5.0 ${\mu}m$ based on a double layer of conducting polymers. The device, fabricated with poly(3-hexylthiophene) (P3HT) and poly(3,4-ethylenedioxythiophene) (PEDOT) as the first and second layers, respectively, showed an transmittance contrast of 60% with a response rate under 5 s, which is greater than the transmittance contrast of cells based on only P3HT or PEDOT (approximately 40%).

Patternable PEDOT nanofilms with grid electrodes for transparent electrochromic devices targeting thermal camouflage

Kim Bumsoo,Koh Jong Kwan,Park Junyong,Ahn Changui,Ahn Joonmo,Kim Jong Hak,전석우 나노기술연구협의회 2015 Nano Convergence Vol.2 No.19

This paper reports a new type of transmitting mode electrochromic device that uses the high-contrast electrochromism of poly(3,4-ethylenedioxythiophene) (PEDOT) and operates at long-wavelength infrared (8–12 μm) . To maximize the transmittance contrast and transmittance contrast ratio of the device for thermal camouflage, we control the thickness of the thin PEDOT layer from 25 nm to 400 nm and develop a design of grid-type counter electrodes. The cyclability can be greatly improved by selective deposition of the PEDOT film on grid electrodes as an ion storage layer without any loss of overall transmittance. The device with optimized architectures shows a high transmittance contrast ratio of 83 % at a wavelength of 10 μm with a response rate under 1.4 s when alternating voltage is applied. Captured images of an LED lamp behind the device prove the possibility of active, film-type camouflage against thermal detection.

Epigallocatechin Gallate Activates Phospholipase D in Glioma Cells

Kim, Shi-Yeon,Kim, Joonmo,Min, Do-Sik Korean Society of Life Science 2003 생명과학회지 Vol.13 No.6

녹차의 주성분인 에피갈로 갈레이트 (EGCG)는 건강에 이로운 효과로 나타내고 있는것으로 알려져 있어 많은 주목을 받고 있는 실정이다 본 연구에서는 처음으로 EGCG가, U87사람의 교세포에서 포스포리파제 D의 효소활성을 증가시킨다는 사실을 규명하였다. EGCG에 의한 포스포리파제 D의 활성화는 포스포리파제 C효소의 특이적인 억제제와 지질분해효소 활성이 억제제 포스포리파제 \gama1$의 변이체를 이용하여 실험한 결과 세포내 칼슘에 의존적인 양상을 보였주었다. 이러한 포스포리파제 D의 활성화는 아마도 칼슘 의존성 단백질 키나아제 II (CaM kinase II)를 통하여 일어나는것으로 여겨진다. 흥미롭게도, EGCG는 포스포리파제 \gama1$를 세포질에서 세포막으로의 이동을 유도하였으며, 포스포리파제 \gama1$와 PLD1의 결합을 유도하였음을 관찰하였다. 이상의 결과들을 종합하여 볼 때, EGCG가 사람의 교세포에서 포스포리파제 \gama1$-칼슘-CaM kinase II의 신호전달 경로를 통하여 포스포리파제 D의 활성을 유도하는 것으로 사료된다. Epigallocatechin-3 Gallate (EGCG), a major constituent of green tea, has attracted increasing interest because of its many reported health benefits. Here we demonstrate for the first time that EGCG stimulates phospholipase D (PLD) activity in U87 human astroglioma cells. EGCG-induced PLD activation was abolished by the phospholipase C (PLC) inhibitor and a lipase inactive PLC-\gama1$ mutant, and was dependent on intracellular $Ca^{ 2+}$, and possibly involved $Ca^{ 2+}$ calmodulin-dependent protein kinase II (CaM kinase II). Interestingly, EGCG induced translocation of PLC-\gama1$ from the cytosol to the membrane and PLC-\gama1$interaction with PLD1. Taken together, these results demonstrate for the first time that in human astroglioma cells, EGCG regulates PLD activity via a signaling pathway involving a PLC-\gama1$ (inositol 1,4,5-trisphosphate-$Ca^{ 2+}$)-CaM kinase II-PLD pathway.

Visible Color Tunable Emission in Three-Dimensional Light Emitting Diodes by MgO Passivation of Pyramid Tip

Kim, Ji-Hyun,Ye, Byeong Uk,Park, Joonmo,Yoo, Chul Jong,Kim, Buem Joon,Jeong, Hu Young,Hur, Jin-Hoe,Kim, Jong Kyu,Lee, Jong-Lam,Baik, Jeong Min American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.50

<P>We demonstrated visible color tunable three-dimensional (3D) pyramidal light emitting diodes by depositing the MgO on and near the tip of the pyramid as an insulating layer. Here, we show that the degradation of the materials (i.e., <I>p</I>-GaN) crystallinity and the built-in electric field due to the nanoscale geometry of the tip region is responsible for the large leakage current observed in LEDs. Confocal scanning electroluminescence microscopy images clearly showed that the intensity of the light emitted out of the side facet of the pyramid is much higher than that of the light extracted out of the tip surface, indicating that the MgO layer prohibited the carrier injection to the MQWs layer, suppressing the leakage occurring at or near the tip region of the pyramids. The color range of the LEDs can be also tuned by using the MgO layer, a blue-shift by 10.3 nm in the wavelength. This technique is simple and scalable, providing a promising solution for developing 3D pyramidal LEDs with low leakage current and controllable light emission.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2015/aamick.2015.7.issue-50/acsami.5b08729/production/images/medium/am-2015-08729j_0001.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am5b08729'>ACS Electronic Supporting Info</A></P>

Phospholipase D Activity is Elevated in Hepatitis C Virus Core Protein-Transformed NIH 3T3 Mouse Fibroblast Cells

Kim, Joonmo,Jung, Eun-Young,Jang, Kyung-Lib,Min, Do-Sik Korean Society of Life Science 2003 생명과학회지 Vol.13 No.5

C형 간염바이러스는 간암을 야기하는 심각한 바이러스이다. C형 간염바이러스의 core 단백질의 과발현은 섬유아세포를 암화시키는 것으로 알려져 있다. Phospholipase D (PLD)의 효소활성이 세포증식 신호전달에 의해 활성화되어 있으며, 사람의 암조직에서 과발현 및 활성이 증가되어 있는 것으로 알려져 있다. 본 연구의 목적은, core 단백질에 의해 암화된 세포에서 PLD가 어떻게 조절되는지를 이해하고자 하는 것이다. 자극이 없는 상태에서뿐만 아니라 PMA에 의해 유도되는 PLD효소활성은, 암화된 세포에서 더 증가하였으며, control 세포와 core 단백질에 의해 암화된 세포에서 PLD와 PKC 단백질의 발현은 서로 유사하였다. PKC 특이적인 억제제와 PKC의 세포막으로의 이동에 관한 실험을 통해서, PKC-d가 암화된 세포에서 PMA에 의해 유도되는 PLD활성의 증가에 중요하게 관여하고 있음을 밝혔다. 이러한 결과는, PLD가 core 단백질에 의해 유도되는 세포의 암화과정에 관여하고 있을 것으로 추정된다. Hepatitis C Virus (HCV) is associated with a severe liver disease and increased frequency in the development of hepatocellular carcinoma. Overexpression of HCV core protein is known to transform fibroblast cells. Phospholipase D (PLD) activity is commonly elevated in response to mitogenic signals, and PLD has been also reported to be overexpressed and hyperactivated in some human cancer. The aim of this study was to understand how PLD can be regulated in HCV core protein-transformed NIH3T3 mouse fibroblast cells. We observed that in unstimulated state, basal PLD activity was higher in NIH3T3 cells overexpressing HCV core protein than in vector-transfected cells. Although expression of PLD and protein kinase C (PKC) in core protein-transformed cells was similar with that of control cells, phorbol 12-myristate 13-acetate (PMA), which is known to activate PKC, stimulated significantly PLD activity in core protein-transformed cells, compared with that of the control cells. PLD activity assay using PKC isozyme-specific inhibitor, and PKC translocation experiment showed that PKC-$\delta$ was mainly involved in the PMA-induced PLD activation in the core-transformed cells. Taken together, these results suggest that PLD might be implicated in core protein-induced transformation.

AN APPROXIMATION SCHEME FOR A GEOMETRICAL NP-HARD PROBLEM

Joonmo Kim 한국산업응용수학회 2007 Journal of the Korean Society for Industrial and A Vol.11 No.4

In some wireless sensor networks, the sensor nodes are required to be located sparsely at designated positions over a wide area, introducing the problem of adding minimum number of relay nodes to interconnect the sensor nodes. The problem finds its abstract form in literature: the Minimum number of Steiner Points. Since it is known to be NP-hard, this paper proposes an approximation scheme to estimate the minimum number of relay nodes through the properties of the abstract form. Note that by reducing the number of nodes in a sensor network, the amount of data exchange over the net will be far deer eased.

광대역 정규 프로세스에 대한 주파수 영역 기반 피로해석법의 적용성에 관한 연구 I

정준모(Joonmo Choung),김경수(Kyung Su Kim),남지명(Ji-Myung Nam),구정본(Jeong-Bon Koo),김민수(Min-Soo Kim),심용래(Yong Lae Shim),엄항섭(Hang-Sub Urm) 대한조선학회 2012 大韓造船學會 論文集 Vol.49 No.4

Generation of Dynamic Routing Information by using Balanced Howell Rotations

김준모(Joonmo Kim) 大韓電子工學會 2011 電子工學會論文誌-TC (Telecommunications) Vol.48 No.2

통신 노드들이 이동 중인 mobile ad hoc networks에서, 통신처리율에 따라 노드 쌍들의 순위를 결정하면, 이를 바탕으로 전체 네트워크의 처리율을 향상시키는 동적인 라우팅을 할 수 있다. Balanced Howell rotations는 브리지 게임을 위한 토너먼트구성 방법의 하나이다. 본 논문에서는 mobile ad hoc networks의 전반적인 통신 처리율 향상을 위해 balanced Howell rotations를 활용할 수 있음을 설명한다. 그리고 balanced Howell rotations가 존재할 수 있는 조건을 제시하고, 이를 증명한다. In mobile ad hoc networks where the communication nodes are moving around, one may perform dynamic routing that can increase the total communication throughput of the network, by determining the ranks of pairs of nodes according to their communication throughput. The balanced Howell rotation is a tournament design scheme for bridge games. This paper explains that the balanced Howell rotation can be applied to enhance the overall communication throughput of mobile ad hoc networks, and proposes and proves the condition under which the balanced Howell rotations may exist.

부모와 자녀가 함께 하는 법질서 기능성 게임설계 연구

김병욱(Kim, Byoung-Wook),김경식(Kim, KyungSik),강준모(Kang, JoonMo),박형준(Park, HyungJoon) 한국게임학회 2015 한국게임학회 논문지 Vol.15 No.6

법과 질서 교육은 현대사회에서 반드시 필요한 교육이다. 그러나 초등학생들에게는 접근하기 어려운 주제로서, 학습 효율을 높이기 쉽지 않다. 본 연구에서는 게임을 교육 콘텐츠로 접목하는 효율적 학습 방식으로 게임의 순기능을 활용하는 방식을 연구하였다. 아이들은 게임을 통해서 다양한 법질서 상황을 만나면서 다양한 생각과 판단을 하도록 게임을 설계하였다. 법과 질서 교육에 아이의 가장 훌륭한 멘토인 부모가 참석하여 적절한 역할 밸런스를 담당하도록 게임 콘텐츠를 설계하였다. 프로토타입으로 제작한 게임 체험과 설문을 통해서 부모와 아이가 함께하는 교육 게임의 효율성을 테스트하였다. 본 연구를 통해 향후에도 아이들의 교육에 게임이라는 콘텐츠가 좋은 학습 도구가 될 수 있다는 점을 보이는데 기여하고자 한다. Education of 'Law and Order' is necessary in our recent society. However it is so difficult subject for students in the elementary schools to be learned efficiently. In this research, we have studied how to utilize the game as an educational contents with good effects of the game. And we have designed a game in which children could experience various situations where they had to make decisions based on proper law and order. Parents were also encouraged to participate and play along the game with role balances as mentors to their children. The effectiveness was tested with experience of the developed prototype game and questions. Through the study we expect and hope to use games as effective learning tools for children in the future.