• Journal of architectural history
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• v.11 no.4 s.32
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• pp.45-69
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• 2002

This study aims to find out the genetic characteristics of gridded subdivision area which has its origin from ancient local administrative city-Sangju, Jeonju, Namwon, Kwangju, Chungju. The spatial structure, based on the inter-relationship among gridded subdivision area, city wall, and topographic condition, and the morphological characteristics of gridded subdivision area are analyzed. The points of analysis on morphological characteristics of gridded subdivision area consist of the size of unit block, the organization system of unit block, the orientation of subdivision line. As a result of the analysis, three main characteristics are found. Firstly there can be found no same land subdivision rule among study areas. Secondly, the morphological features of study area were the products of cumulative process of different subdivision areas which were developed in different periods. Thirdly, the original regular gridded land subdivision seems to have been carried out in the object of a farm-land cultivation around 7th century. And there was a change of land-use from farm land to urban land-use during the later 7th century and 8th century.

• Journal of Internet Computing and Services
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• v.11 no.4
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• pp.95-106
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• 2010

Recently multiple process communicate together. They share resource and information for cooperation in complicated programming environment. Kernel provides IPC (Inter -Process Communication) for communication with each other process. Shared Memory is a technique that many processes can access to identical memory area in the Linux environment. In this paper, we propose a performance improvement method of shared memory in the dual-core embedded linux system which is consist of different core and different operating system. We construct the MPC2530F (ARM926F+ARM946E) linux system and measure the performance therein. We attempt a performance enhancement in each CPU for each process which uses a shared memory.

• Journal of Positioning, Navigation, and Timing
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• v.3 no.2
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• pp.71-81
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• 2014

Time synchronization system using dual frequency bands is designed and the error sources are analyzed for alternative synchronized-pseudolite navigation system (S-PNS) which aims at military application. To resolve near/far problem, dual frequency band operation is proposed instead of pulsing transmission which degrades level of reception. In dual frequency operation H/W delay should be considered to eliminate errors caused by inter-frequency bias (IFB) difference between the receivers of the pseudolites and users. When time synchronization is performed across the sea, multipath error is occurred severely since the elevation angle between pseudolites is low so total reflection can be happened. To investigate the difference of multipath effects according to location, pseudolites are set up coastal area and land area and performances are compared. The error source related with tropospheric delay is becoming dominant source as the coverage of the PNS is broadening. The tropospheric delay is measured by master pseudolite receiver directly using own pseudorange and slave pseudorange. Flight test is performed near coastal area using S-PNS equipped with developed time synchronization system and test results are also presented.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.121-125
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• 2003

This study discusses how the appropriate distribution and logistic information system of the railroad industry will be developed when the Korean railroad will be open toward northeast Asia area through South Korea and China/Russia in the rail-ferry project and/or the inter-Korean railroad connection project in the fnture. This study suggests that the Korea railroad industry should build the own efficient information system of railroad distribution and logistics in the notheast Asia area far both the extension of customer services and the competition with peripheral countries around the pacific.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.31-34
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• 2000

It is very important to understand the correlation of between inter layer dielectric(ILD) CMP process and various facility factors supplied to equipment system. In this paper, the correlation between the various facility factors supplied to CMP equipment system and ILD CMP process were studied. To prevent the partial over-polishing(edge hot-spot) generated in the wafer edge area during polishing, we analyzed various facilities supplied at supply system. With facility shortage of D.I. water(DIW) pressure, we introduced an adding purified $N_2(PN_2)$ gas in polishing head cleaning station for increasing a cleaning effect. DIW pressure and PN2 gas factors were not related with removal rate, but edge hot-spot of patterned wafer had a serious relation. We estimated two factors (DIW pressure and PN2 gas) for the improvement of CMP process. Especially, we obtained a uniform planarity in patterned wafer and prohibited more than 90% wafer edge over-polishing. In this study, we acknowledged that facility factors supplied to equipment system played an important role in ILD-CMP process.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.570-575
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• 2004

This paper deals with the exchange of tourists and the operation of sightseeing train encouraged by the inter-Korean cross-border railway project. First of all, how the inter-Korean cross-border railway project has developed will be discussed. After this, the present tourism state, facilities, the state of railways and roads of North Korea, and major tourist attraction around the Kyonguisun will be shown. And then, several aspects on the agreements between the Korean National Railroad (KORAIL) and North Korean railroad system will be summarized. And, finally, the economic effect of the line including the operation schedule of the Kyonguisun sightseeing train, the demand forecast, the computation of railway fare, and profit sharing will be depicted.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 1998.11a
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• pp.20-25
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• 1998

In order to support effective decision-making related to inter-sewage planning, this study proposes the spatial distribution method of inter-sewage treatement area using spatial analysis of GIS, Communication system of database, spatial interaction of Gravity model. Evalution Indexs are consist of economic, social/political and environmental condition value which are explained by the analysis of AHP algorithm ,based on opinion of related experts. Network module in Arc/Info is applied in order to find out minimum pipeline root in Miho river watershed, one of the sub-basin of Geum river basin. This value also is utilized for the construction of cost decay function in gravity model.

• Transactions on Electrical and Electronic Materials
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• v.12 no.4
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• pp.131-134
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• 2011

Back-end-of-line using ultra low-k (ULK; k < 2.5) has been required to reduce resistive capacitance beyond 45 nmtechnologies, because micro-processing units need higher speed and density. There are two strategies to manufacture ULK inter-layer dielectric (ILD) materials using an air-gap (k = 1). The former ULK and calcinations of ILD degrade the mechanical strength and induce a high cost due to the complication of following process, such as chemical mechanical polishing and deposition of the barrier metal. In contrast, the air-gap based low-k ILD with a relatively higher density has been researched on the trench-type with activity, but it has limited application to high density devices due to its high air-gap into the next metal layer. The height of air-gap into the next metal layer was reduced by changing to the via-typed air-gap, up to about 50% compared to that of the trench-typed air-gap. The controllable ULK was easily fabricated using the via-typed air-gap. It is thought that the via-type air-gap made the better design margin like via-patterning in the area with the dense and narrow lines.

• Journal of Electrical Engineering and Technology
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• v.4 no.4
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• pp.443-450
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• 2009

This paper deals with the design of decentralized controller for load-frequency control of interconnected power systems with superconducting magnetic energy storage units and Governor Dead Band Nonlinearity using Multi-Objective Evolutionary Algorithm. The superconducting magnetic energy storage unit exhibits favourable damping effects by suppressing the frequency oscillations as well as stabilizing the inter-area oscillations effectively. The proposed control strategy is mainly based on a compromise between Integral Squared Error and Maximum Stability Margin criteria. Analysis on a two-area interconnected thermal power system reveals that the proposed controller improves the dynamic performance of the system and guarantees good closed-loop stability even in the presence of nonlinearities and with parameter changes.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.10
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• pp.502-508
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• 2000

This paper presents a dynamic simulation algorithm for studying the effect of United Power Flow Controller(UPFC) on the low frequency power system oscillations and transient stability studies. The proposed algorithm is a Newton-type one and uses current injection type UPFC model, which gives a fast convergence characteristics. The algorithm is applied to studying inter-area power oscillation damping enhancement of a sample two-area power system both in time domain and frequency domain. The case study results show that the proposed algorithm is very efficient and UPFC is very effective and robust against operating point change.