FGF-mediated FGFR signaling 이 두개봉합부의 초기형태발생 및 유지기전에 미치는 영향

남순현,김영진,서경환,김현정,박미현,유현모 大韓小兒齒科學會 1999 大韓小兒齒科學會誌 Vol.26 No.4

두개봉합부의 조기융합으로 알려진 Craniosynostosis는 두개봉합부 주위 조직들 사이의 조화로운 상호 작용이 파괴되었을 때 야기될 수 있다. 흥미롭게도 FGF receptor들, 특히 FGFR2의 point mutation은 여러 가지 형태의 craniosynostosis 증후군과 연관되어 있어, FGFR가 두개봉합부를 포함한 두개골 성장 발달과정에 중요한 유전자임을 시사하고 있다. Mouse 두개봉합부의 초기형태발생시 FGFR 유전자들의 기능을 알아보기위해, in situ hybridization 방법을 이용하여 FGFR2(BEK) 및 골아세포분화의 초기표지자인 osteopontin이, 태생기(E15-18)에서 출생후(P1-P3)까지, 두개골의 시상봉합부에서의 발현양상을 조사하였다. FGFR2(BEK)은 osteogenic front에 강하게 발현되었으며, osteopontin은 parietal bone의 exo-, endocranial부위에서 발현되었으나, parietal bone의 성장가장자리인 osteogenic front에서는 관찰되지 않았다. 두개봉합부에서의 FGF-mediated FGFR signaling의 역할을 좀더 심도깊게 조사 하기위해 E15.5 mouse의 두개골을 이용하여 in vitro 실험을 시행하였다. 흥미롭게도 osteogenic fronts 및 시상봉합부의 간엽조직 중앙에 FGF2 - soaked beads를 점적하여 36시간 기관배양한 결과, bead주위 조직들의 두께 및 세포수가 증가되었으며, osteogenic fronts 상에 FGF4 beads를 올려놓은 경우, 시상두개봉합부 중앙에 점적된 FGF4 beads나 BSA control beads에 비해, 골성장이 촉진되어 시상두개봉합부의 부분적인 소멸을 관찰할 수 있었다. 이와 더불어 FGFR2 beads는 osteopotin 및 Msxl 유전자의 발현을 유도하였다. 이 결과들을 종합해 볼 때, FGF - mediated FGFR signaling이 발육중인 두개골과 두개봉합부에서 세포의 증식과 분화의 균형을 조절하는데 중요한 담당하고 있음을 시사해주고 있으며, 이 과정중 FGF signaling이 osteopontin 및 Msxl 유전자의 발현을 조절하므로써 막내골 성장 및 두개봉합부의 유지기전에 기여할 것으로 사료된다. Craniosynostosis, the premature fusion of cranial sutures, presumably involves disturbance of the interactions between different tissues within the cranial sutures. Interestingly, point mutaions in the genes encoding for the fibroblast growth factor receptors(FGFRs), especially FGFR2, cause various types of human craniosynostosis syndromes. To elucidate the function of these genes in the early morphogenesis of mouse cranial sutures, we first analyzed by in situ hybridization the expression of FGFR2(BEX) and osteopontin, an early marker of osteogenic differentiation, in the sagittal suture of calvaria during embryonic (E15-E18) and postnatal stage (P1 - P3). FGFR2(BEK) was intensely expressed in the osteogenic fronts, whose cells undergo differentiation into osteoprogenitor cells that ultimately lay down the bone matrix. Osteopontin was expressed throughout the parietal bones excluding the osteogenic fronts, the periphery of the parietal bones. To further examine the role of FGF-mediated FGFR signaling in cranial suture, we did in vitro experiments in E15.5 mouse calvarial explants. Interestingly, implantation of FGF2 soaked beads onto both the osteogenic fronts and mid-mesenchyme of sagittal suture after 36 hours organ culture resulted in the increase of the tissue thickness and cell number around FGF2 beads, moreover FGF4-soaked beads implanted onto the osteogenic fronts stimulated suture closure due to an accelerated bone growth, compared to FGF4 beads placed onto mid-mesenchyme of sagittal suture and BSA control beads. In addition FGF2 induced the ectopic expression of osteopontin and Msxl genes. Taken together, these data indicate that FGF-mediated FGFR signaling has a important role in regulating the cranial bone growth and maintenance of cranial suture, and suggest that FGF-mediated FGFR signaling is involved in regulating the balance between the cell proliferation and differentiation through inducing the expression of osteopontin and Msxl genes.

Alternative Capturability Analysis of PN Laws

Ryoo, Chang-Kyung,Kim, Yoon-Hwan,Tahk, Min-Jea The Korean Society for Aeronautical and Space Scie 2006 International Journal of Aeronautical and Space Sc Vol.7 No.2

The Lyapunov stability theory has been known inadequate to prove capturability of guidance laws because the equations of motion resulted from the guidance laws do not have the equilibrium point. By introducing a proper transformation of the range state, the original equations of motion for a stationary target can be converted into nonlinear equations with a specified equilibrium subspace. Physically, the equilibrium subspace denotes the direction of missile velocity to the target. By using a single Lyapunov function candidate, capturability of several PN laws for a stationary target is then proved for examples. In this approach, there is no assumption of the constant speed missile. The proposed method is expected to provide a unified and simplified scheme to prove the capturability of various kinds of guidance laws.

대동맥판폐쇄부전으로 나타난 Supraaortic Ridge와 Subaortic Membrane의 증례

류정곤,김윤철,성보영,김준경,정준용,성인환,전은석,나명훈,이영 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.8

Terrain Data Aided Passive Ground Target Tracking

Chang-Hwan Kim,Keeyoung Choi,Chang-Kyung Ryoo,Kyeong-Dae Park,Jin-Bok Kim,Ki-Sung Kim,Jong-Lae Jo 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

The primary purpose of passive tracking function is to support weapon systems on the military aircraft. Aground-attacking aircraft must know the precise location of the target to fulfill its missions. The target tracking system must estimate location of the target passively, if the need of stealth performance is highly required. A target is designat-ed using integrated sensors, such as Helmet Mounted Sights, Laser Designators, FLIR(Forward-Looking Infrared Ra-dar), IRSTs(Infra-Red Search and Track), and RF Precision Direction Finding Equipments. These sensors can accuratelyprovide the LOS(Line Of Sight) angle measurements to a ground target passively, but they cannot provide a measure-ment of range which is required to determine the location of targets on the ground. However, by using of stored digital terrain data, the target’s location can be calculated. The digital terrain aided passive target tracking algorithm consists of the LOS intersection algorithm and the Kalman Filter.

Alternative Capturability Analysis of PN Laws

Chang-Kyung Ryoo,Yoon-Hwan Kim,Min-Jea Tahk 한국항공우주학회 2006 International Journal of Aeronautical and Space Sc Vol.7 No.2

The Lyapunov stability theory has been known inadequate to prove capturability of guidance laws because the equations of motion resulted from the guidance laws do not have the equilibrium point. By introducing a proper transformation of the range state, the original equations of motion for a stationary target can be converted into nonlinear equations with a specified equilibrium subspace. Physically, the equilibrium subspace denotes the direction of missile velocity to the target. By using a single Lyapunov function candidate, capturability of several PN laws for a stationary target is then proved for examples. In this approach, there is no assumption of the constant speed missile. The proposed method is expected to provide a unified and simplified scheme to prove the capturability of various kinds of guidance laws.

Core Binding Factor β of Osteoblasts Maintains Cortical Bone Mass via Stabilization of Runx2 in Mice : OSTEOBLAST CBFβ MAINTAINS CORTICAL BONE MASS

Lim, Kyung-Eun,Park, Na-Rae,Che, Xiangguo,Han, Min-Su,Jeong, Jae-Hwan,Kim, Shin-Yoon,Park, Clara Yongjoo,Akiyama, Haruhiko,Kim, Jung-Eun,Ryoo, Hyun-Mo,Stein, Janet L,Lian, Jane B,Stein, Gary S,Choi, J Wiley Blackwell (John Wiley Sons) 2015 Journal of bone and mineral research Vol.30 No.4

Core Binding Factor β of Osteoblasts Maintains Cortical Bone Mass Via Stabilization of Runx2 in Mice

Lim, Kyung-Eun,Park, Na-Rae,Che, Xiangguo,Han, Min-Su,Jeong, Jae-Hwan,Kim, Shin-Yoon,Park, Clara Yongjoo,Akiyama, Haruhiko,Kim, Jung-Eun,Ryoo, Hyun-Mo,Stein, Janet L,Lian, Jane B,Stein, Gary S,Choi, J Wiley (John WileySons) 2015 Journal of bone and mineral research Vol.30 No.10

A Missile Guidance Law Based on Sontag's Formula to Intercept Maneuvering Targets

Chang-Kyung Ryoo,Yoon-Hwan Kim,Min-Jea Tahk,Keeyoung Choi 대한전기학회 2007 International Journal of Control, Automation, and Vol.5 No.4

In this paper, we propose a nonlinear guidance law for missiles against maneuvering targets. First, we derive the equations of motion described in the line-of-sight reference frame and then we define the equilibrium subspace of the nonlinear system to guarantee target interception within a finite time. Using Sontag's formula, we derive a nonlinear guidance law that always delivers the state to the equilibrium subspace. If the speed of the missile is greater than that of the target, the proposed law has global capturability in that, under any initial launch conditions, the missile can intercept the maneuvering target. The proposed law also minimizes the integral cost of the control energy and the weighted square of the state. The performance of the proposed law is compared with the augmented proportional navigation guidance law by means of numerical simulations of various initial conditions and target maneuvers.

선택적 전송 다이버시티 기법과 최적의 터보 부호화된 V-BLAST 기법을 적용한 적응 변조 시스템의 성능 개선

이정환 ( Jeong Hwan Lee ),윤길상 ( Gil Sang Yoon ),류상진 ( Sang Jin Ryoo ),이경환 ( Kyung Hwan Lee ),김철성 ( Cheol Sung Kim ),황인태 ( In Tae Hwang ) 전남대학교 전자통신기술연구소 2007 전자통신기술논문지 Vol.10 No.1

본 논문에서는 V-BLAST (Vertical-Bell-lab Layered Space Time) 복호 알고리즘의 ordering과 slicing 과정에 MAP(Maximum A Posteriori) 디코더의 외부 정보 (extrinsic information)를 이용한 최적의 터보 부호화된 (Optimal Turbo Coded) V-BLAST 적응 변조 시스템을 제안 후 성능을 관찰한다. 외부정보는 ordering과 slicing에 사전 확률 (a priori probability) 로서 사용되며 시스템 복호 과정은 주 반복 (Main Iteration) 및 부 반복 (Sub Iteration) 과정으로 이루어진다. 채널 상태에 따라 변조 방식을 달리하는 적응 변조 시스템을 기존의 터보 부호화 (Turbo Coding) 된 V-BLAST 시스템과 최적의 터보 부호화된 V-BLAST 시스템에 각각 적용하고 전송률 (throughput) 및 SNR (Signal to Noise Ratio)을 비교하여 제안된 시스템을 적용할 경우 어느 정도의 성능 개선이 있는가를 살펴본다. 또한, 제안된 시스템에 선택적 전송 다이버시티 (STD: Selection Transmit Diversity) 기법을 적용한 후 성능의 향상을 관찰한다. 모의 실험결과, 적응 변조 시스템에서 최적의 터보 부호화된 V-BLAST 기법을 적용한 경우가 기존의 터보 부호화된 V-BLAST 기법을 적용한 경우에 비하여 전체적인 SNR 영역에서 SNR 이득이 나타났고 11 dB의 SNR에서 최대 약 350 kbps의 전송률 향상이 나타났다. 또한 제안된 시스템에 선택적 전송 다이버시티가 적용된 경우에는 기존 시스템과 비교하여 같은 SNR 영역에서 최대 약 1.77 Mbps의 전송률이 개선됐으며, 특히 4Mbps의 전송률 성능을 만족시키기 위한 SNR 성능에서는 약 5.88dB의 이득을 보였다. In this paper, we propose and observe the Adaptive Modulation system with optimal Turbo Coded V-BLAST(Vertical-Bell-lab Layered Space-Time) technique that is applied the extrinsic information from MAP (Maximum A Posteriori) Decoder in decoding Algorithm of V-BLAST ordering and slicing. The extrinsic information is used by a priori probability and the system decoding process is composed of the Main Iteration and the Sub Iteration. And comparing the proposed system with the Adaptive Modulation system using conventional Turbo Coded V-BLAST technique that is simply combined V-BLAST with Turbo Coding scheme, we observe how much throughput performance and SNR (Signal to Noise Ratio) has been improved. In addition, we observe the proposed system using STD (Selection Transmit Diversity) scheme. As a result of simulation, Comparing with the conventional Turbo Coded V-BLAST technique with the Adaptive Modulation systems, the optimal Turbo Coded V-BLAST technique with the Adaptive Modulation systems has SNR gain over all SNR range and better throughput gain that is about 350 Kbps in 11 dB SNR range. Also, comparing with the conventional Turbo Coded V-BLAST technique using 2 transmit and 2 receive antennas, the proposed system with STD(Selection Transmit Diversity) scheme show that the improvement of maximum throughput is about 1.77 Mbps in the same SNR range and the SNR gain is about 5.88 dB to satisfy 4 Mbps throughput performance.

Guidance Synthesis for Evasive Maneuver of Anti-Ship Missiles Against Close-In Weapon Systems

Kim, Yoon-Hwan,Ryoo, Chang-Kyung,Tahk, Min-Jea IEEE 2010 IEEE transactions on aerospace and electronic syst Vol.46 No.3

<P>In this paper, we propose a guidance synthesis method for enhancing anti-ship missiles' survivability against ship-borne CIWS (close-in weapon system). Using CEALM (coevolutionary augmented Lagrangian method), a direct optimization technique, an optimal control problem to minimize time-varying weighted sum of the inverse of aiming errors of CIWS is solved. The optimal evasive trajectory exhibits sinusoidal acceleration commands, which results in barrel-roll type evasive maneuvers. Inspired by the optimization results, a 3-dimensional biased proportional navigation guidance (PNG) law to induce a barrel-roll maneuver during the homing phase is proposed. Capturability of the proposed guidance law is proved by using the Lyapunov stability theory. A proper choice of the barrel-roll direction also guarantees that the missile altitude can be made lower bounded. Performance of the proposed guidance laws is compared with conventional PNG via simulations.</P>