• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.754-762
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• 2021

Seamless wireless communication network access technology enables users to guarantee service continuity. Hence, it is necessary for disaster situations in which network service may be interrupted. The Multi-path router is a technology to improve network stability and strengthen field operability, particularly in a disaster environment where network failure can occur by providing high-performance data transmission using multi-communication networks and network security by VPN-based wireless IP. In this paper, a prototype system for an MPR-based wireless communication network was proposed to improve the operation performance for disaster field investigation applications. A comparative experiment was performed on various data transmission performances with the existing single wireless communication network. In addition, another experiment was conducted by measuring the data packet transmission and receiving performance in the existing/new wireless communication system first and then assessing the UDP transmission performance in a single router environment to understand the transmission capability of the new MPR. The experimental results showed that the sending and receiving performance was improved by approximately double that of the existing single wireless communication system. The proposed prototype system is expected to allow users to share and disseminate collected on-site data more quickly and efficiently during a disaster site investigation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.929-935
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• 2008

As internet telephony services based on Session initiation Protocol (SIP) enter the spotlight as marketable technology, many products based on SIPs have been developed and utilized for home and office telephony services. The call connection of an internet phone is classified into specific call connections and group call connections. Group call connections have a forking function which delivers the message to all of the group members. This function requires excessive message control for a call connection and creates heavy traffic in the network. In the internet cail system model. most of the call-setup messages are directed to the proxy server during a short time period. This heavy message load brings an unwanted delay in message processing and. as a result, call setup can not be made. To solve the delay problem, we simplified the analysis of the call-setup message in the proxy server, and processed the forking function distributed for the group call-setup message. In this thesis, a new system model to minimize the load is proposed and the subsequent implementation of this model demonstrates the performance improvement.

• Journal of Astronomy and Space Sciences
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• v.32 no.1
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• pp.73-80
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• 2015

The Yang-gyeong-gyu-il-ui (兩景揆日儀) is a kind of elevation sundial using three wooden plates. Sang-hyeok Lee (李尙爀, 1810~?) and Byeong-cheol Nam (南秉哲, 1817~1863) gave descriptions of this sundial and explained how to use it in their Gyu-il-go (揆日考) and Ui-gi-jip-seol (儀器輯說), respectively. According to Gyu-il-go (揆日考) there are two horizontal plates and two vertical plates that have lines of season and time. Subseasonal (節候) lines are engraved between seasonal (節氣) lines, subdividing the interval into three equal lines of Cho-hu (初候, early subseason), Jung-hu (中候, mid subseason) and Mal-hu (末候, late subseason); there are 13 seasonal lines for a year, thus resulting in 37 subseasonal lines; also, there are 12 double-hour (時辰) lines for a day engraved on these plates. The only remaining artifact of Yang-gyeong-gyu-il-ui was made in 1849 (the $15^{th}$ year of Heon-jong) and is kept at the Korea University Museum. We have compared and analyzed Yang-gyeong-gyu-il-ui and similar western sundials. Also, we have reviewed the scientific aspect of this artifact and built a replica. Yang-gyeong-gyu-il-ui is a new model enhanced from the miniaturization development in the early Joseon Dynasty and can be applied to the southern part of the tropic line through a structure change.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.2
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• pp.277-284
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• 2009

With significant development in wireless communication technologies, the needs to handover from one network to another have grown dramatically. Recently IETF developed MIPv6 and FMIPv6 which are used to handover between different access networks. These handover mechanisms have some known weaknesses. MIPv6 can not serve time-critical application because it causes long handover latency and packet loss. By these reasons, MIPv6 does not guarantee session continuity. FMIPv6 uses handover preparation phase to reduce DAD latency. However FMIPv66 still suffers from long handover latency, because it must perform binding update at the end of handover procedure. In this paper we propose new handover mechanism FMIPv6-PBU which eliminates binding update latency. The proposed mechanism has compatability with lagacy FMIPv6. In this paper propose FMIPv6-PBU handover procedure and explain its procedures and evaluate it with MIPv6 and FMIPv6.

• The Korean Journal of Pharmacology
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• v.32 no.3
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• pp.323-334
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• 1996

Male Mongolian gerbils $(60{\sim}80g)$ were given DL-difluoromethylornithine (DFMO; 250mg/kg, ip) and methylglyoxal bis(guanylhydrazone) (MGBG; 50 mg/k, ip), respectively, 1 h prior to transient (7 min) occlusion of bilateral common carotid arteries (OBC7) and a daily dose of one of them for 6 days after recirculation, and the polyamine contents, activities of ornithine and S-adenosylmethionine decarboxylases (ODC and SAM-DC), and light microscopic findings of the hippocampus were evaluated. The hippocampal putrescine (PT) levels of the control gerbils treated with saline (STGr), markedly increased after OBC7, showing a peak level at 24 h after recirculation. The peak PT level was reduced in DFMO treated gerbils (DTCr) and in MGBG treated gerbils (MTGr). And 7 days after recirculation, the PT level of DTGr was decreased to about 75% of the PT level in the sham operated group (nonTGr) and to about 55% of the STGr level, respectively. The hippocampal spermidine (SD) level of STGr tended to decline, showing the lowest value at 8 h after recirculation. But the spermidine (SD) level of DTGr was somewhat higher at 8 h after OBC7 than those of STGr and MTGr The hippocampal spermine (SM) levels of all the experimental groups were little changed for 7 days after OBC. OBC7 markedly increased the hippocampal ODC activity. reaching a maximum (about 3 times higher than preischemic level) at 8 h and rapidly recovered to the control value by 24 h in STGr gerbils, and the OBC7-induced increase of ODC activity was significantly attenuated by DFMO or MGBG treatment. Whereas OBC7 induced a rapid decrease of the hippocampal SAMDC activity follwed by gradual recovery to the preischemic level, and the decrease of the SAMDC activity was slightly attenuated by DFMO or MGBG treatment. 7 Days after OBC7 the histological finding of the hippocampal complex stained with cresyl violet showed an extensive delayed neuronal damage in the CA1 region and to a lesser extent, in the dentate gyrus, sparing the CA3 region. And the neuronal death was aggevated by DFMO but significantly attenuated by MGBG. The immunochemical reactivity of hippocampus to anti-GFAP antibody was significantly increased in the CA1 region and to a lesser extent, in the dentate gyrus 7 days after OBC7, but was little changed in the CA3. And the increase of the anti-GFAP immunoreactivity was moderately enhanced by DFMO and significantly suppressed by MGBG. These results suggest that the polyamine metabolism may play a modulatory role in the ischemic brain damage.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2633-2640
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• 2009

We design a small-area, low-power, and high-speed EEPROM for touch screen controller IC. As a small-area EEPROM design, a SSTC (side-wall selective transistor) cell is proposed, and high-voltage switching circuits repeated in the EEPROM core circuit are optimized. A digital data-bus sensing amplifier circuit is proposed as a low-power technology. For high speed, the distributed data-bus scheme is applied, and the driving voltage for both the EEPROM cell and the high-voltage switching circuits uses VDDP (=3.3V) which is higher than the logic voltage, VDD (=1.8V), using a dual power supply. The layout size of the designed 128-KBit EEPROMIP is $662.31{\mu}m{\times}1314.89{\mu}m$.

• Applied Microscopy
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• v.27 no.3
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• pp.333-346
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• 1997

The ischemia and reperfusion injury of the skeletal muscles is caused by generation of reactive oxygen during ischemia and reperfusion. It is well known that over 4 hours of ischemia injures the skeletal muscles irreversibly. The author has demonstrated the effects of SOD (superoxide dismutase), DMTU (dimethyl thiourea) and ischemic preconditioning on ultrastructural changes of the muscle fibers in the rectus femoris muscles after 4 hours of ischemia and 1 day and 3 days of reperfusion. A total of 72 healthy Sprague-Dawley rats weighing from 200 gm to 250 gm were used as experimental animals. Under urethane(1.15 g/kg, IP, 2 times) anesthesia, lower abdominal incision was done and the left common iliac artery was occluded by using vascular clamp for 4 hours. The left rectus femoris muscles were obtained at 1 and 3 days after the removal of vascular clamp. The SOD (15,000 unit/kg) or DMTU (500 mg/kg) were administered intraperitoneally at 1 hour before induction of ischemia. The ischemic preconditioned group underwent three episodes of 5 minutes occlusion and 5 minutes reperfusion followed by 4 hours of ischemia and 1 day and 3 days of reperfusion. The specimens were sliced into $1mm^3$ and prepared by routine methods for electron microscopic observation. All specimens were stained with uranyl acetate and lead citrate and then observed with Hitachi-600 transmission electron microscope. The results were as follows: 1. SOD or DMTU alone did not affect the ultrastructure of muscle fibers in the rectus femoris muscles. The electron density of mitochondrial matrix was decreased by ischemic preconditioning. 2. Dilated cisternae of sarcoplasmic reticulum, triad, mitochondria and the loss of myofilament in the sarcomere were observed in the 4 hours ischemia and 1 day reperfused rectus femoris muscles. Markedly changed sarcoplasmic reticulum, triad, disordered or loss of myofilament, indistinct A-band and I-band, and irregular electron lucent M -line and Z-line are seen in the 4 hours ischemia and 3 days reperfused rectus femoris muscles. 3. SOD reduced the changes of organelles in the muscle fibers of the 4 hours ischemia and 1 day reperfused rectus femoris muscles of the rats, but SOD did not affect the changes of muscle fibers in the 4 hours ischemia and 3 days reperfused muscles. On the other hand, DMTU markedly attenuated considerably the ultrastructural change of the 4 hours ischemia and 1 day or 3 days reperfused rectus femoris muscles. 4. By the ischemic preconditioning, the change was attenuated remarkably in the 4 hours ischemia and 1 day reperfused rectus femoris muscles. As the ischemic reperfused changes of muscle fibers were regenerated or recovered by ischemic preconditioning, the ultrastructures of them were similar to those of normal control in the 4 hours ischemia and 3 days reperfused rectus formoris muscles. Consequently, it is suggested that DMTU is stronger inhibitor to ischemic reperfused change than SOD. The ischemia and reperfusion-induced muscular damage is remarkably inhibited by ischemic preconditioning.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.4
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• pp.67-80
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• 2022

SipWooDo (十牛圖: Painting of Ten Bulls), a Buddhist painting, is a kind of Zen Sect Buddhism painting, which is shown as a mural in many of main halls of Korean Buddhist temples. MokWooDo has been painted since Song Dynasty of China. It paints a cow, a metaphor of mind and a shepherd boy who controls the cow. It comes also with many other types of works such as poetry called GyeSong, HwaWoonSi and etc. That is, it appeared as a pan-cultural phenomenon beyond ideology and nation not limited to Chinese Buddhist ideology of an era. This study, therefore, selects MokWooDo chants that represent Confucianism, Buddhism and Taoism to compare the writing purposes, mind discipline methods and ultimate goals of such chant literatures in order to integrate and comprehend the ideologies of such three schools in the ideologically cultural aspect, which was not fully dealt with in the existing studies. In particular, the study results are: First, the SipWooDo of Buddhist School is classified generally into Bo Myoung's MokWooDo and Kwak Ahm's SimWooDo (尋牛圖: Painting of Searching out a Bull). Zen Sect Buddhism goes toward nirvana through enlightenment. Both MokWooDo and SimWooDo of Buddhist School are the discipline method of JeomSu (漸修: Discipline by Steps). They were made for SuSimJeungDo (修心證道: Enlightenment of Truth by Mind Discipline), which appears different in HwaJe (畫題: Titles on Painting) and GyeSong (偈頌: Poetry Type of Buddhist Chant) between Zen Sect Buddhism and Doctrine Study Based Buddhism, which are different from each other in viewpoints. Second, Bo Myoung's MokWooDo introduces the discipline processes from MiMok (未牧: Before Tamed) to JinGongMyoYu (眞空妙有: True Vacancy is not Separately Existing) of SsangMin (雙泯: the Level where Only Core Image Appears with Every Other Thing Faded out) that lie on the method called BangHalGiYong (棒喝機用: a Way of Using Rod to Scold). On the other side, however, it puts its ultimate goal onto the way to overcome even such core image of SsangMin. Third, Kwak Ahm's SimWooDo shows the discipline processes of JeomSu from SimWoo (尋牛: Searching out a Bull) to IpJeonSuSu (入鄽垂手: Entering into a Place to Exhibit Tools). That is, it puts its ultimate goal onto HwaGwangDongJin (和光同塵: Harmonized with Others not Showing your own Wisdom) where you are going together with ordinary people by going up to the level of 'SangGuBori (上求菩提: Discipline to Go Up to Gain Truth) and HaHwaJungSaeng (下化衆生: Discipline to Go Down to Be with Ordinary People)' through SaGyoIpSeon (捨敎入禪: Entering into Zen Sect Buddhism after Completing a Certain Volume of Doctrine Study), which are working for leading the ordinary people of all to finding out their Buddhist Nature. Fourth, Shimiz Shunryu (清水春流)'s painting YuGaSipMaDo (儒家十馬圖: Painting of Ten Horses of Confucian School) borrowed Bo Myoung's MokWooDo. That is, it borrowed the terms and pictures of Buddhist School. However, it features 'WonBulIpYu (援佛入儒: Enlightenment of Buddhist Nature by Confucianism)', which is based on the process of becoming a greatly wise person through Confucian study to go back to the original good nature. From here, it puts its goal onto becoming a greatly wise person, GunJa who is completely harmonized with truth, through the study of HamYang (涵養: Mind Discipline by Widening Learning and Intelligence) that controls outside mind to make the mind peaceful. Its ultimate goal is in accord with "SangCheonJiJae, MuSeongMuChee (上天之載, 無聲無臭: Heaven Exists in the Sky Upward; It is Difficult to Get the Truth of Nature, which has neither sound nor smell)' words from Zhōngyōng. Fifth, WonMyeongNhoYin (圓明老人)'s painting SangSeungSuJinSamYo (上乘修真三要: Painting of Three Essential Things to Discipline toward Truth) borrowed Bo Myoung's MokWooDo while it consists of totally 13 sheets of picture to preach the painter's will and preference. That is, it features 'WonBulIpDo (援佛入道: Following Buddha to Enter into Truth)' to preach the painter's doctrine of Taoism by borrowing the pictures and poetry type chants of Buddhist School. Taoism aims to become a miraculously powerful Taoist hermit who never dies by Taoist healthcare methods. Therefore, Taoists take the mind discipline called BanHwanSimSeong (返還心性: Returning Back to Original Mind Nature), which makes Taoists go ultimately toward JaGeumSeon (紫金仙) that is the original origin by changing into a saint body that is newly conceived with the vital force of TaeGeuk abandoning the existing mind and body fully. This is a unique feature of Taoism, which puts its ultimate goal onto the way of BeopShinCheongJeong (法身淸淨: Pure and Clean Nature of Buddha) that is in accord with JiDoHoiHong (至道恢弘: Getting to Wide and Big Truth).

• Tuberculosis and Respiratory Diseases
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• v.56 no.5
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• pp.465-484
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• 2004

Background : Insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) inhibits the proliferation of non-small cell lung cancer (NSCLC) cells by inducing apoptosis. Methods : In this study, we investigated whether hypermethylation of IGFBP-3 promoter play an important role in the loss of IGFBP-3 expression in NSCLC. We also studied the mechanisms that mediate the silencing of IGFBP-3 expression in the cell lines which have hypermethylated IGFBP-3 promoter. Results : The IGFBP-3 promoter has hypermethylation in 7 of 15 (46.7%) NSCLC cell lines and 16 (69.7%) of 23, 7 (77.8%) of 9, 4 (80%) of 5, 4 (66.7 %) of 6, and 6 (100%) of 6 tumor specimens from patients with stage I, II, IIIA, IIIB, and IV NSCLC, respectively. The methylation status correlated with the level of protein and mRNA in NSCLC cell lines. Expression of IGFBP-3 was restored by the demethylating agent 5'-aza-2'-deoxycytidine (5'-aza-dC) in a subset of NSCLC cell lines. The Sp-1/ Sp-3 binding element in the IGFBP-3 promoter, important for promoter activity, was methylated in the NSCLC cell lines which have reduced IGFBP-3 expression and the methylation of this element suppressed the binding of the Sp-1 transcription factor. A ChIP assay showed that the methylation status of the IGFBP-3 promoter influenced the binding of Sp-1, methyl-CpG binding protein-2 (MeCP2), and histone deacetylase (HDAC) to Sp-1/Sp-3 binding element, which were reversed by by 5'-aza-dC. In vitro methylation of the IGFBP-3 promoter containing the Sp-1/Sp-3 binding element significantly reduced promoter activity, which was further suppressed by the overexpression of MeCP2. This reduction in activity was rescued by 5'-aza-dC. Conclusion : These findings indicate that hypermethylation of the IGFBP-3 promoter is one mechanism by which IGFBP-3 expression is silenced and MeCP2, with recruitment of HDAC, may play a role in silencing of IGFBP-3 expression. The frequency of this abnormality is also associated with advanced stages among the patients with NSCLC, suggesting that IGFBP-3 plays an important role in lung carcinogenesis/progression and that the promoter methylation status of IGFBP-3 may be a marker for early molecular detection and/or for monitoring chemoprevention efforts.