• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.157-160
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• 1988

This paper describes the development of the Interfacing unit between PSTN and interphone network. The designed and realised system detects the ring signal from PSTN and makes off-hook condition when it is detected. Then the caller can hear the response tone from the unit and the tones of the interphone network condition. The developed system receives the interphone number to which the caller wants to connect by MFC tones and drives Interphone switch matrix. Thus, a call is connected to the interphone user directly. The caller may press the interphone number up to 10 digits and the last two of which are recognized as valid ones. The caller must press the first digit within 20 seconds after system response.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11b
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• pp.1423-1426
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• 2002

본 논문은 사람이 아닌 단말기 스스로 통화가능자를 검출하는 방법을 제시한다. 기존의 제품들은 사람이 스스로 발신음(RingBack Tone)을 듣고 있다가 통화를 시도하거나 일부 대형 업체에서는 단말기 스스로 Auto-Redialing하여 통화 가능자클 검출하였다. 하지만 그러한 검출방법의 비공개로 인하여 정확한 방법을 얻기는 힘들뿐 아니라 영세한 기업에서 그러한 시스템을 도입하기에는 비용상 어려운 문제에 부딪치게 된다. 본 논문에서는 연속적인 발신음(RB)의 주파수를 분석하여 패턴이 틀어지는 시점을 기준으로 통화가능자 검출 방법을 제시한다. 본 논문의 서론에서는 현재 국내 외 CTI업체, 국내 CTI분야에 적용되는 음성처리기술의 표준동항, 통신망의 변화, 콜센터 시장동향 및 새로운 부가기능의 연구목적을 제시하고 있으며, 본론에서는 컴퓨터와 일반 전화기의 통합(CTI)하에 부가기능을 수행할 수 있는 통화가능자 검출이론 및 방법과 발신자의 안내 멘트에 의한 간접적인CID 기능을 접목하는 방법을 제시하였으며, 결론에서는 본 논문에서 제안하는 MINI CTI의 요약 및 검출 기능의 향후 발전방안에 대해서 모색해 본다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.4
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• pp.450-467
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• 1998

The characteristics of the unstable impinging circular jet is investigated based on the frequency characteristics and the sound field of the impinging-tones. Two symmetric modes S1 and S2, associated with low frequency and high frequency respectively, and one helical mode H have been observed. At low speed the S2 mode is dominant and switched by the S1 mode as the speed increases. When the jet speed is high the S1 mode is very active over the impinging distance from half the nozzle diameter to its ten times, while the S2 mode occurs at shorter distance corresponding to stage 2 and 3. The helical mode H seems unstable, likely to be influenced much by the experimental environment, and occurs at relatively high speed with almost the same frequency characteristics as the S2 mode. By estimating the convection speed of the unstable jet, it is found that the ratio of the convection speed to the jet speed decreases with both Strouhal number and Reynolds number and the speed of S2 mode is faster than the Si mode. When the present experimental results are compared with the previous investigations performed for the hole tone and the impinging tone with a small plate, the S1 mode is found to be associated with the ring vortex of large diameter with low speed, but the S2 mode with the vortex of small diameter with high speed. In addition, the frequency is found to be influenced by the nozzle configuration but the characteristics is almost the same. From the impinging distance and frequency range, it can be deduced that S1 mode is related with the jet column mode and S2 mode with the shear mode.

• YAKHAK HOEJI
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• v.37 no.2
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• pp.163-171
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• 1993

In order to study the functions of vascular endothelial nitric oxide(NO) generating system, we examined the effects of monomethylarginine(MMA) and dimethylarginine(DMA)(asym., sym.), arginine analogues, on modulation of vascular tone. Also, the concentrations of endogenous arginie and MMA were measured by HPLC in rat aortic tissues. The results were as follows. 1. The maximum relaxation induced by Ach (1.5$\times$10$^{-6}$M) was 80% of the contractility of rings of rat aorta induced by phenylephrine and L-Arg causes endothelium-dependent relaxation of the aorta precontracted with phenylephrine and these relaxation were concentration-dependent. 2. Endothelium-dependent contractility of rings of rat aorta induced by MMA (100 $\mu{M}$), DMA (asym., 100 $\mu{M}$) and DMA (sym., 100 $\mu{M}$) were 25.5%, 27.5% and 16.5% of that induced by phenylephrine respectively. 3. The relaxation of rat aortic ring induced by L-Arg was inhibited by MMA, DMA(asym.) and DMA(sym.). The degrees of inhibition induced by MMA, DMA(asym.) and DMA(sym.) were 45.7%, 37.1% and 18.3%, respectively. 4. The endogenous arginine and monomethylarginine contents in rat aorta were 83 pmoles/mg wet tissue, and 34.9 pmoles/mg wet tissue. After stimulation with Ach, the concentrations of L-Arg and MMA were significantly decreased. These results suggest that there are the strong relationships between the endogenous L-Arg and methylated arginines and NO-generating system.

• The Journal of the Acoustical Society of Korea
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• v.36 no.3
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• pp.186-193
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• 2017

Silla Great Bell was manufactured in order to ring for the new millennium in succession to King Seongdeok Divine Bell. This study investigates how Silla Great Bell is similar to King Seongdeok Divine Bell in respect of structure and sound. First, design and manufacturing processes are introduced and dimensions of the two bells are compared and the similarity is estimated. Three main characteristics of the sound of a Korean bell are magnificent and harmonic striking sound, dynamic beat, and long lasting hum tone. These three features are compared and objectively estimated using physical parameters. The purpose of the study is to provide useful information to manufacture Korean bell which has beautiful appearance and excellent sound.

• Polymer(Korea)
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• v.24 no.3
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• pp.407-417
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• 2000

Photosensitive polyimides having cyclobutane or phenyl and aromatic sulfonyloxyimide units in the main chain have been synthesized and the photodegradation behavior was investigated in relation with the polymer structure. The polyimides were prepared by condensation polymerization of N-hydroxyl and sulfonyl chloride. The prepared polyimides were stable up to 25$0^{\circ}C$ without thermal degradation. It has been found that the photodegradation of polyimides upon irradiation of 254 nm UV light results from scission of N-O bonds or ring opening of imides moiety by spectroscopic measurements. The polyimides were useful as positive working photodegradable polymers. Especially, the positive tone image of polyimide containing a pyromellitic diimide moiety exhibited high sensitivity and resolution.

• Journal of Integrative Natural Science
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• v.15 no.2
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• pp.83-87
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• 2022

In this study, through a survey on traffic safety campaigns for electric wheelchairs for the disabled, we found out what is necessary to solve the inconvenience of disabled people driving electric wheelchairs and living in society. The conclusions for each role of the severely disabled are as follows. The government has enacted a law on fostering convenience facilities for the disabled in accordance with reality so that the disabled, who are vulnerable to transportation, do not have any inconvenience in their social lives. However, it is not kept in reality, so there are many obstacles to the social activities of the disabled. In addition, local governments should subscribe to electric wheelchair insurance for the disabled to minimize the damage to the disabled in the event of an electric wheelchair accident. Organizations related to the disabled provide safety wheelchair driving education to prevent electric wheelchair accidents in advance and receive complaints about inconvenience. It can be concluded that people with severe disabilities can prevent accidents in advance by installing a moving ring tone on an electric wheelchair so that they can know the movement of the surrounding wheelchair.

• Journal of Ginseng Research
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• v.26 no.1
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• pp.1-5
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• 2002

It has been well known that Korea red ginseng has an antihypertensive effect. The antihypertensive effect may be due to its ability to change the peripheral resistance. Change of vascular tone in the resistance-sized artery contribute to the peripheral resistance, thereby regulate the blood pressure. Therefore, we investigated to clarify the vasorelaxing mechanism induced by crude saponin of Korea red ginseng in the resistance-sized mesenteric artery of rats. The resistance-sized mesenteric artery was isolated and cut into a ring. The ring segment was immersed in HEPES-buffered solution and its isometric tension was measured using myograph force-displacement transducer. Crude saponin of ginseng relaxed the mesenmetric arterial rings precontracted with norepinephrine (3$\mu$M) in dose-dependent manner (0.01 mg/㎖ -1 mg/㎖. The relaxation by crude saponin was smaller in endothelium-intact preparation than that in endothelium-denuded preparation. The contraction induced by A23187 or phorbol 12,13-dibutyrate was not affected by crude saponin of ginseng. The vasorelaxing effect of crude saponin of ginseng was significantly attenuated by the increase of the extracellular K$\^$+/ concentration. Crude saponin-induced vasorelaxation was not affected by tetraethylammonium (1 mM), glybenclamide (10$\mu$M), and 4-aminopyridine (0.1 mM) in these preparations. Ba$\^$2+/(10$\mu$M ∼100$\mu$M) markedly reduced the crude saponin-induced vasorelakation dose-dependently. From the above results, we suggest that crude saponin of ginseng may stimulate K$\^$+/ efflux and hyperpolarize the membrane, thereby cause the vasorelaxation in the resistance-sized mesenteric artery of rats.

• IMMUNE NETWORK
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• v.9 no.3
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• pp.106-113
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• 2009

Background: We previously demonstrated remarkable differences in the expression of IL-8/CXCL8 in aortic tissues and vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR) compared to VSMC from normotensive Wistar-Kyoto rats (WKY). In the present study, we investigated the direct effect of IL-8/CXCL8 on expression of 12-lipoxygenase (LO), a hypertensive modulator, in SHR VSMC. Methods: Cultured aortic VSMC from SHR and WKY were used. Expression of 12-LO mRNA was determined by real-time polymerase chain reaction. Phosphorlyation of ERK1/2 and production of 12-LO and angiotensin II subtype 1 ($AT_1$) receptor were assessed by Western blots. IL-8/CXCL8-stimulated DNA synthesis was determined by measuring incorporation of [$^3H$]-thymidine. And effect of IL-8/CXCL8 on vascular tone was determined by phenylephrine-induced contraction of thoracic aortic rings. Results: Treatment with IL-8/CXCL8 greatly increased 12-LO mRNA expression and protein production compared to treatment with angiotensin II. IL-8/CXCL8 also increased the expression of the $AT_1$ receptor. The increase in 12-LO induced by IL-8/CXCL8 was inhibited by treatment with an $AT_1$ receptor antagonist. The induction of 12-LO mRNA production and the proliferation of SHR VSMC by IL-8/CXCL8 was mediated by the ERK pathway. The proliferation of SHR VSMC and the vascular contraction in the thoracic aortic ring, both of which were induced by IL-8/CXCL8, were inhibited by baicalein, a 12-LO inhibitor. Conclusion: These results suggest that the potential role of IL-8/CXCL8 in hypertensive processes is likely mediated through the 12-LO pathway.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.695-706
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• 1998

SST (Sea Surface. Temperature) fronts which were found in the South-West Sea of Korea and the northern area of the East China Sea were examined in order to clarify their positions, shapes, seasonal changes and the formation mechanism, For this study used SST data rearranged from the SST IR image during 1991 to 1996 and oceanographical data obtained by National Fisheries Research and Development Institute. Temperature front in the Cheju Strait was analyzed by the data obtained from a fisheries guidance ship of Cheju Provincial Government, The coastal frontal zone in the South-West Sea of Korea and the offshore frontal zone in the northern area of the East China Sea can be divided into several types (Type of Winter, Summer, Spring, Autumn and late Autumn), Short term variations of SST fronts have a tendency not to move to any Bleat extent for several days. The location of the frontal zone in the southwestern sea of Cheju Island changes on a much large scale than that of the one in the southern coast of Korea, The frontal Tone, formed every year in the southern sea of Korea approaches closer to the coastal area in winter, and moves closer to the south in spring and autumn. The frontal zone of the southwestern sea of Cheju Island moves in a westerly direction from the east, and reaches its most westerly point in the winter and its most easterly point in the summer related to the seasonal change of the Tsushima Current. Additionally, the frontal zone of the southwestern sea of Korea becomes extremely weak in March, April and November. SST fronts are formed every year around the line connecting Cheju Island to Yeoseo Island or to Chungsan Island in the Cheju Strait. A Ring-shaped tidal mixing front appears along the coastal area of Cheju Island throughout the year except during the months from November to January. Especially, in May and October fronts are formed between the coastal waters of Cheju Island and the Tsushima currents connecting the frontal zone of the coastal region in the southern sea of Korea with that of the southwestern sea of Cheju Island.