• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.06a
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• pp.201-210
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• 2000

The noncontacting groove end face seal is one of various approaches to sealing gases with a single seal. Gas pumped into groove maintains operating gap and lubricates between primary ring and mating ring. So it removes heat and decreases face wear. In this paper, K-type and T-type grooved seals have been analyzed numerically using the finite element method. It explains the effects of groove shapes in gas seals along rotating speeds with a temperature gradient, face distortion, stress and so on. The calculated FEM results show the operating gap and rotating speed are strongly related to the leakages of a gas seal and that T-type groove seal shows a good thermal performance compared to K-type groove seal.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.3
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• pp.133-141
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• 1996

As the recording density of digital magnetic recording channels increased, the nonlinear distortion caused by inadequate rise-times, demagnetizing field, and overwrite effect during the recording process becomes significant, resulting in limitation on the recording rate. In this paper, a new method for identifying the nonlinear distortion in hihg-density magnetic recording channel using and i.i.d. (independent, identically distributed) inut is described. The proposed method does not require the operatin of large-size matrix inversion which are necessary for the conventional method, and it enables us to estimate nonlinear parameters transition shifts, which can be used to compensate the nonlinear distortion, is demonstrated by computer simulations.

• Journal of the Korean Institute of Navigation
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• v.15 no.1
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• pp.67-93
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• 1991

In general, marine casualities take palace by the composite action of three elements such as waterway condition, vessel condition and man condition. One of the important characteristics of most marie casualties for small cargo vessels in maritime transportation of near-coastal and greater-coasting seas in that the same kind of casualities take place repeatedly in spite of the apprent causes, Because, it takes much time and effort for seamen to master waterway, vessel or operatin technique only to the practical and sensible level. In these days, with the development of our economy, our shiypping industry has grown and therefore the demand of marine officers has increased. This economic growth brought about undesirable situation like the evasion of seamen and frequent casualities of Korea vessels. These marine casualities are being caused mainly by the unskilfulness of operating technique as well as the bad waterway condition and ship's installation condition. Therefore, I conclude, in this paper, that the most efficient and economic preventing measures of marine casualities are seeking causes and removing them in advance under the close coperation system among all concerned parties.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.534-537
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• 1998

In this paper, a set of novel self-timed latches are introduced and analyzed. These latches have no back-to-back connection as in conventional self-timed latch, and both inverting and noninerting outputs are evaluated simultaneously leading to thigher oepating frequencies. Power consumption of these latches ar ealso comparable to or less than that of conventional circuits. Novel type of cross-coupled inverter used in the proosed circuits implements static operatin without signal fighting with the main driver during signal transition. Proposed latches ar tested using a 0.6.mu.m triple-poly triple-metal n-well CMOS technology. The resutls indicates that proposed active-low sefl-timed latch (ALSTL) improves speed by 14-34% over conventional NAND SR latch, while in active-high self-timed latch (AHSTL) the improvements are 15-35% with less power as compared with corresponding NORA SR latch. These novel latches have been successfully implemented in a high-speed synchronous DRAM (SDRAM).

• Journal of Mechanical Science and Technology
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• v.14 no.10
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• pp.1089-1103
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• 2000

A Problem of relevant interest to some industries is that of obtaining optimum two-dimensional layout. To solve this provlem, one is given a number of rectangular sheets and an order for a specified number of each of certain types of two-dimensional regular and irregular shapes. The aim is to cut the the shapes out of the sheets in such a way as to minimize the amount of waste produced. A DCS (Distributed Control System) is an integrated system which applies the decentralization concept to a control system handling both sequential and analog control. A DCS performs many operations such as data gathering, data processing, data storing and monitoring the operatin conditions for the operator. IN this paper, we propose a genetic algorithm based on rotation parameters from which the best pattern of layout is found as well as a layout method for better performance time. A DCS for the plate cutting process system, which is performed by a virtual system, is also identified.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.139-147
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• 1993

The rapid industrial growth, the consequent shortage of farm labour and increase in their wage level have facilitated more capitalized agricultural mechanization pattern in Korea. The efficiency of capital intensive machine is highly dependent on farm land structure. This paper describes a model explaining the relationship between farmland structure and required inputs for machine operation and to estimate required inputs for machine operation on the national basis for Korea for its paddy production system. The machine cost is closely related to operation area, but the required labour-hours are more related to machine type adopted . From the technology introduction point of view, if capital intensive machine is introduced, less labour-hours are required but machine kW-hours increase rapidly. From the plot geometry point of view, on good geometry plots, machine kW-hour and labour-hour required are less than that on the poor geometry plots. The kW-jhour per hectare of mechani al energy input id better indicator of mechanization level than kW per hectare or number of machine. If the adopted technology is more capital intensive and plot geometry is good, the cost reduction effect is highly significant.

• Convergence Security Journal
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• v.15 no.3_2
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• pp.21-30
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• 2015

Current video surveillance system that is being used in the country are composed of different video surveillance s ystem that is produced in a number of domestic and foreign manufacturers and perform a service. These video surv eillance systems are using different protocols and interfaces, operating method, it provides such performance without interworking and interoperability between the video surveillance systems, in accordance with the purpose of operatin g the subject is being operated separately. Therefore, in order to provide an image with a more systematic and effici ent security service, many operational constraints are requested. The present study defines the standardization for a unified standard interfaces and protocols to ensure the interworking and interoperability between the different individ ual video security system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.13-18
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• 2006

In this paper, occurrence tendency of the sick and wounded on board ship is analyzed. The medical management systems according to shipping companies are investigated. Furthermore, comparative analysis with the medical support system for seafarers in advanced country is carried out.

• Journal of Chest Surgery
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• v.33 no.1
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• pp.7-19
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• 2000

Background :To assess the accuracy of Electron-Beam Tomography(EBT) in following evaluation of the pulmonary vascular system after a shunt operation in the cyanotic con-genital heart disease with pulmonary stenosis or pulmonary atresia. Material and Method : Sixteen patients(M:F=11:5) who received Blalock-Taussig(n=8) bidirectional cavo-pulmonary shunt(n=10) and unifocalization (n=2) were ncluded in the study. We evaluated the patency of the shunt the morphology of intrapericardial and hilar pulmonary arteries(PA) peripheral pulmonary vascularity by background lung attenuation and the abundance of arterial & venous collateral. Angiography(n=12) and echocardiography(n=20) were used as the gold standard for the comparison of EBT results. Result: EBT was consistent with angiogram/ echo in 100% of the evaluation for the patency of the shunt and in 12(by angiogram 100%) and 19(by echo 95%) for the detection the hypoplasia stenosis or interruption of central PA In measuring of PA EBT and angiogram corrlated(r=0.91) better than EBT-echo(r=0.88) or echo-angiogram(r=0.72) Abundant systemic arterial collateral were noted in 4 and venous collateral in 3 cases. In evaluating the peripheral pulmonary vascularity the homogenous and normal-ranged lung attenuation(m=6) decreased but homo-genous attenuation(n=1) segment-by-sgment heterogeneous attenuation(n=3) homogenous but asymmetrical attenuation(n=3) segment-by-segment heterogeneous attenuation(n=3) homogenous but asymmetrical attenuation(n=3) and venous congestion(n=2) were observed nd 12 of them were compatible with the blood flow pattern revealed by cardiac catheterization. Conclusion: EBT was accurate in the integrated evaluation of the pulmonary vascular system after the shunt including the patency of the shunt operaion the morphology and dimension of the central and hilar PAs and the loco-regional pulmonary flow in the lung parenchyma. It suggests the useful information about the need of secondary shunt operation the proper timing time for total repair and the need of interventional procedure prior to total repair.

• Journal of Chest Surgery
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• v.33 no.4
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• pp.301-305
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• 2000

Background: The surgical indications of stage IV non-small cell lung cancer(NSCLC) are extremely limited with its controversial results. We analyzed the surgical results and survival in selected patients with resectable stage IV NSCLC. Material and Method: We reviewed the medical records of 21 patients who underwent operation for stage IV NSCLC from Jan. 1992 to Sep. 1999. Result: The mean age of patients was 55.6 years(range: 35 to 78). Sixteen were men and 5 were women. Tissue types were squamous cell carcinoma in 10(45.5%), adenocarcinoma in 9(40.9%), large cell carcinoma in 1 and carcinosarcoma in 1. Distant metastatic lesions were ipsilateral other lobe of lung in 18, brain in 2 and adrenal gland in 1. Pneumonectomy was performed in 16 patients, bilobectomy in 3, and lobectomy in 2 who underwent previous operatin for brain metastasis. Mean follow-up duration was 21.2$\pm$17.7 months. During follow-up period, 13 patients died. Three-and 5-year survival of patients were 38.0% and 19.0%, the median survival time was 19.1$\pm$7.8 months. In the group with ipsilateral pulonary metastasis(PM, n=18), 3- and 5-year survival of patients with N0 and N1(n=9) disease were 64.8% and 32.4%, median survival time was 55.3$\pm$27.2 months. Three-year survival of patients with N2(n=9) disease was 11.1%, median survival time was 10.6$\pm$0.3 months. The survival of N0 and N1 disease group was significantly better than that of N2 disease group(p=0.042). Also the disease free survival of N0 and N1 was significantly better than that of N2 disease in overall group(53.3 months vs 12.1 months, p=0.036) and ipsilateral PM group(63.4 months vs 8.8 months, p=0.001). Conclusion: We suggest that surgical treatment is worthful modality in well selected patients with stage IV NHSCLC especially with ipsilateral PM and N0 or N1 disease,. Nevertheless our study indicate questions that will need to be experienced further in larger studies.