• Title/Summary/Keyword: Ho and Hyoung

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Experimental study of vertical fence wake with flow separator (Flow separator가 부착된 수직벽 후류유동의 실험적 연구)

  • Choi, Young-Ho;Kim, Hyoung-Bum
    • 한국가시화정보학회:학술대회논문집
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    • 2006.12a
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    • pp.68-72
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    • 2006
  • Vertical fence has the coherent flow structure in front of the fence. In the present study, the wake change due to the flow separator in front of the vertical fence was experimentally investigated. Quantitative method was applied to study the separated shear flow field. The results show the flow separator changes the downstream shear flow and alters the curvature of separated shear layer As the freestream velocity increased, the reattachment length also increased.

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A STUDY ON MODIFIED MEMBERSHIP FUNCTION BASED ON FREQUENCY VARIATION OF LPC

  • Choi, Seung-Ho;Kim, Hyoung-Guen
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1994.06a
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    • pp.1092-1097
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    • 1994
  • To solve the frequency variation of speech patterns which consist of LPC sequences, a new membership function made by the relation between order of LPC and spectrum is proposed in this paper. To reduce errors, fuzzy inference is executed using the proposed membership function. The computer simulation shows the effectiveness of the word recognition.

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A Study on Network Reliability Analysis for Information Security (정보 보호를 위한 네트워크 신뢰성 분석에 관한 연구)

  • Yu, Hyoung-Seok;Park, Hong-Keun;Ryu, In-Ho;Kim, Hyoung-Jin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.10
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    • pp.3935-3941
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    • 2010
  • With the advent of high-speed communications networks, many authentication and access control systems are being introduced to combat network security issues like system hacking. But the fact is that the security systems for protecting information used in these networks are themselves weak. In response to the mounting demands of existing users, there is a clear need for a new authentication system that provides both safety and reliability. This research presents an authentication method with excellent access authorization (explicit and implicit authentication) and safety performance, demonstrated through its use in online networks.

Prediction of the Shelf-life of Chilled Foods at Various Temperatures

  • Park, Sae-Rom;Lee, Yu-Si;Ha, Ji-Hyoung;Park, Ki-Hwan;Lee, Sook-Yeon;Choi, Youn-Ju;Lee, Dong-Ho;Park, Sun-Hee;Ryu, Kyung;Shin, Hyoung-Soo;Bae, Dong-Ho;Kim, Ae-Jung;Ha, Sang-Do
    • Applied Biological Chemistry
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    • v.51 no.4
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    • pp.329-333
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    • 2008
  • This study was designed to estimate the shelf-life of the popular chilled foods kimbab (rice rolled in dried laver), samgak kimbab (triangular rice rolled in dried laver), eomook (fish surimi, boiled fish paste) mook (acorn-starch jelly), and tofu (soybean curd) in large discount markets and convenience stores. Different types of chilled foods were stored at 5, 7, and 10 for 7 and 28 days, and changes in the total numbers of the aerobic bacteria were monitored. Values of 6 and 7 log cfu/g were used as the standard. Ready-to-eat foods stored at 5 showed a much longer shelf-life compared to storage at 10. The respective percentage increases in the shelf-life observed at both 7 and 5 were kimbab (70%, 171%), samgak kimbab (87%, 143%), soybean curd (46%, 95%), fish surimi (46%, 99%), and mook (45%, 87%). To reduce the microbiological contamination, storages at 7 and 5 are recommended for the increases of 45-88 and 87-171% in the shelf-life of these chilled foods.

Heme Oxygenase-l Induced by Aprotinin Inhibits Vascular Smooth Muscle Cell Proliferation Through Cell Cycle Arrest in Hypertensive Rats

  • Choi, Hyoung-Chul;Lee, Kwang-Youn;Lee, Dong-Hyup;Kang, Young-Jin
    • The Korean Journal of Physiology and Pharmacology
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    • v.13 no.4
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    • pp.309-313
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    • 2009
  • Spontaneous hypertensive rats (SHR) are an established model of genetic hypertension. Vascular smooth muscle cells (VSMC) from SHR proliferate faster than those of control rats (Wistar-Kyoto rats; WKY). We tested the hypothesis that induction of heme oxygenase (HO)-1 induced by aprotinin inhibits VSMC proliferation through cell cycle arrest in hypertensive rats. Aprotinin treatment inhibited VSMC proliferation in SHR more than in normotensive rats. These inhibitory effects were associated with cell cycle arrest in the G1 phase. Tin protoporphyrin IX (SnPPIX) reversed the anti-proliferative effect of aprotinin in VSMC from SHR. The level of cyclin D was higher in VSMC of SHR than those of WKY. Aprotinin treatment downregulated the cell cycle regulator, cyclin D, but upregulated the cyclin-dependent kinase inhibitor, p21, in VSMC of SHR. Aprotinin induced HO-1 in VSMC of SHR, but not in those of control rats. Furthermore, aprotinin-induced HO-1 inhibited VSMC proliferation of SHR. Consistently, VSMC proliferation in SHR was significantly inhibited by transfection with the HO-1 gene. These results indicate that induction of HO-1 by aprotinin inhibits VSMC proliferation through cell cycle arrest in hypertensive rats.

Porcine Dermal Collagen (Permacol) for Sternal Reconstruction

  • Lee, Kwang Hyoung;Kim, Kwang Taik;Son, Ho Sung;Jung, Jae Seung;Cho, Jong Ho
    • Journal of Chest Surgery
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    • v.46 no.4
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    • pp.312-315
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    • 2013
  • In chest wall reconstruction after wide chest wall resection, the use of a musculocutaneous flap or prosthetic materials is inevitable for maintaining thoracic movement and a closed pleural cavity. We report a case of a 63-year-old male with a large invasive thymic carcinoma in the anterior mediastinum. The mass measured 6.8 cm and involved the sternum, left side of the parasternal area, ribs, and intercostal muscles. The patient underwent subtotal sternectomy, radical thymectomy, and reconstruction with biological mesh (Permacol). Successful chest wall reconstruction without any other complications was achieved, demonstrating the effectiveness of Permacol.

A Study on Evaluation Method of Seismic Performance on Cut and Cover Tunnel of Subway in Japan (일본 도시철도 개착식 터널의 내진성능 평가 방법에 대한 고찰)

  • Park, Beom-Ho;Lee, Woo-Chul;Kim, Jin-Ho;Lim, Ham-Hyoung
    • Proceedings of the KSR Conference
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    • 2009.05a
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    • pp.15-19
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    • 2009
  • Due to the Japan's Kobe earthquake in 1995, a cut-and-cover tunnel, which is one of subway facilities, collapsed unexpectedly. As a result, also in Korea, seismic performance needs to be secured for the cut-and-cover tunnel and currently, the subway seismic design standard is based on the seismic performance. However, there is no standard for the damage level or stability level of a member for securing the seismic performance, and the definition of multi-level seismic performance is not sufficient. By contrast to this situation, in the Japan's evaluation method of seismic performance, design earthquake ground motion having reflected there into the subway driving stability is clearly defined and the seismic performance required for structures is classified in detail. This study analyzes the Japan's systematic evaluation method of seismic performance for cut-and-cover tunnels of subway.

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Hydrochemistry of an alluvial aquifer in the Cheonan area: role of the pyrite oxidation on denitrification

  • Kim, Kyoung-Ho;Yun, Seong-Taek;Chae, Gi-Tak;Heo, Chul-Ho;Kim, Hyoung-Soo;Rhee, Chul-Woo;Kim, Kangjoo
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2002.09a
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    • pp.287-290
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    • 2002
  • To examine the denitrification process in an alluvial aquifer in the Cheonan site, hydrological and hydrogeochemical studies were carried out. Elevated levels of NO$_3$ (maximum 77.6 mg/L) were observed in shallow groundwaters of the area, as a result of poultry and agricultural activity. However, the nitrate concentrations were found to be consistently attenuated down to very low levels (<1.0 mg/L). The abrupt removal of nitrate coincided with the pattern of redox change and indicated that denitrification is the most plausible process. The hydrochemistry and mass balance approach using geochemical modeling (phreeqc 2.0) and redox chemistry indicated that chemo-autotrophic denitrification via pyrite oxidation is the key Process to control the nitrate attenuation in the study area.

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Phase-extraction using Zero-Crossing detection in fiber-optic laser interferometry (영점검출을 이용한 광섬유형 레이저 간섭계의 위상추출)

  • Park, Hyoung-Jun;Lee, Jun-Ho;Song, Min-Ho
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2005.05a
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    • pp.426-430
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    • 2005
  • The fiber-optic interferometer which is a powerful application for nondestructive measurement techniques has many advantages such as capability of making portable system, easy optical arrangement, low optical loss. In spite of these advantages, this system has an environmental sensitivity of thermal drifts and vibrations. Against environmental perturbations and nonlinear characteristic of phase modulator, the accurate and fast ${\pi}/2$ phase stepping has been achieved by using zero-crossing detection. CCD camera trigger signal is generated at the 4 zero-crossing points. Our System has achieved up to 100 Hz of image capture speed and 0.6 mrad of accuracy of phase stepping, accuracy.

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