• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.14 no.4
• /
• pp.39-44
• /
• 2014

IMS(IP Multi-Media Subsystem) base on the IP service platform which can offer multimedia as the voice, audio, video, and data is service platform. In 3G mobile communication in the early day, IMS had a suggestion for supporting to multimedia service in the 3GPP. But now It is broadly substituting in the IPTV, wire phone company and it is substituted in internet platform base on the soft-switch in currently. Especially nowadays, 4G LTE in a mobile communication company is rapidly growing in market. Therefore, in this study, we had designed to the main prosser that can admit to 1,000 user over and SIP gateway which can link the IMS 코어 that can link SIP Device which adopt the standard protocol on the SIP.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.4A
• /
• pp.193-199
• /
• 2003

In this paper, the performance of uplink WCDMA systems was analyzed using the SGA (Standard Gaussian Approximation) method and the SIGA(Simplified Improved Gaussian Approximation) method adopted for the performance analysis in conventional DS-CDMA systems. The performance of bandlimited WCDMA systems was analyzed using the SGA and SIGA method, and computer simulations were performed in AWGN environments having multiple access interference. It was shown that the performance analysis of uplink bandlimited WCDMA systems using the SIGa method may be very efficient through various computer simulations with verying spreading factors, roll-off factors, and signal-to-noise ratios.

• Journal of Korean Society for Geospatial Information Science
• /
• v.13 no.3 s.33
• /
• pp.41-52
• /
• 2005

The high density of population and building; can cause catastrophe in urban areas when natural or artificial disasters break out. The aim of this paper is to assess comprehensive disasters risk of urban areas by Geospatial Information System. For this purpose, we classified disasters risk of urban areas into low categories: flood, fire, building-collapse, and shelter, and then determined factors for hazard risk assessment respectively. The results of hazard assessment can be applied to minimize the demage of disasters in establishing the urban management planning. For more systematic and professional approach the further research is need to consider more disaster assessment factors and join with related experts.

• Journal of Korea Foundry Society
• /
• v.27 no.4
• /
• pp.179-183
• /
• 2007

The TiC layer was formed on Ti and Ti alloys by plasma carburizing method. The main experimental parameters for plasma car boozing were temperature and time. XRD, EDX, hardness test and corrosion test were employed to analyze the evolution and material properties of the layer. The preferred orientation of TiC layers is (220) at treated temperature of $700^{\circ}C\;and\;880^{\circ}C$ However, it is changed to (200) at temperature of $800^{\circ}C$ The thickness of carbide layer increase with increasing carburizing temperature. Highest hardness of hardened layer formed on CP-Ti was obtained at the carburizing condition of processing temperature $880^{\circ}C$ and processing time 1080min. The corrosion potential of carburizing specimen was higher than untreated CP-titanium, and corrosion potential increased as carburizing temperature and time increased. Thus the corrosion resistance of CP-Ti was greatly enhanced after plasma carburizing treatment.

• Journal of Korea Spatial Information System Society
• /
• v.2 no.2 s.4
• /
• pp.85-88
• /
• 2000

GPS/GIS Related Information Technology evolves drastically and a great quantity of spatial information is available to users who require highly qualitative spatial information services. Hence the development of GIS tools that can improve position accuracy and maintenance efficiency is required. To meet various requirements from users. we developed a GPS data processing component based on OLE/COM by utilizing GDK which is a unique domestic GIS product. Also we developed an application package that includes the GPS data processing component to implement GPS into GIS. The development of GPS data processing component will contribute toward the expansion of component-wise GIS softwares.

• Fire Science and Engineering
• /
• v.20 no.2 s.62
• /
• pp.21-30
• /
• 2006

Since Daegu subway arson fire disaster in 2003, there have been several copycat crimes such as at Seoul Metro line number seven and Hongkong Chuiwan line cases. Oil and gas were used for fire propagation in most cases as in Daegu case and such fire could be expanded to a whole subway cabin within several minutes. The fire may eventually cause the whole subway system stop. Fire damage can be minimized when fire occurrence and diffusion are blocked by stages or isolated rapidly. This study suggests an effective early response system that separates passengers from fire and a real-time fire extinguishment program by stages. Based on the subway arson case studies, the early response scenario has been structured by three stages, i.e., confirmation of fire and damage, early fire extinguishment, and information dissemination and passengers evacuation.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.39 no.3
• /
• pp.115-127
• /
• 1997

Nonpoint source (NPS) pollution from small watersheds has recently been brought into attention as a potential pollutant to streams and tnbutaries, as majority of them are experiencing water quality degradation. This necessiates the quantification of NPS loadings from agricultural and forested lands. And this study attempts to quantify daily loadings from forested and farm lands using hydrologic and water quality monitoring. The hydrologic monitoring program consists of five water level gauging stations along creeks and stream at the Banweol reservoir watershed having 1220 hectare in size. Water sam pies were taken and analyzeel periodically at the streamf low gaging sites and tributaries. Soil samples were also taken and the chemical constitutes analyzed. The primary results indicate that the major sources of pollution were small villages and dairy farms on the watersheds, constituting two-third of total nutrient loadings to the reservoir. However, the loadings from paddies and upland areas may cause a problem to the water quality of the reservoir and stream as the measured levels of total nitrogen and phosporus are not low enough to ignore. Further studies are needed to quantify the effects of landuses and treatments at a watershed scale.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.11 no.8
• /
• pp.637-645
• /
• 1998

The characteristics of waveguide, electrode and packaging fabricated for acousto-optic tunable filters(AOTF) used for optical communications were analyzed. A $Ti:LiNbO_3$in-diffusing method was employed for the formation of the optical waveguide with a dimension of width $8{\mu}m$, length $30000-50000{\mu}m$ and varying the thickness. The diffusion was carried at $1050^{\circ}C$ for 8 hours to pattern the optical waveguide. The resulted waveguide exhibited a single mode at 1550nm optical wavelength. The width of IDT, with 10 SAM periods, was $5000{\mu}m$ . Impedances of the electrodes deposited with Au were analyzed using a network analyzer; $48.1\Omega$ at the center frequency of 193MHz for electrode thickness of $1500{\AA}$ and $50.7\Omega$ at the center frequency of 192MHz for $1600\AA$. And the characteristics of packaged AOTF was analyzed. When the electrical frequency 177.1MHz was applied to the device, the mode conversion efficiency was measured as 63% at the optical wavelength 1515nm.

• Proceedings of the Korean Information Science Society Conference
• /
• 2010.06b
• /
• pp.368-373
• /
• 2010

플래시 메모리의 집적도가 높아지고 가격이 저렴해 짐에 따라 낸드 플래시 기반의 SSD의 사용이 확산 되고 있다. 플래시 메모리 기반 SSD는 기존의 하드디스크와 비교하여 여러 가지 장점을 가지지만 덮어 쓰기가 불가능한 특성상 쓰기 공간 확보를 위해 가비지 컬렉션이 수행되어야 하는 단점을 가진다. 이러한 단점을 개선하기 위해 다양한 연구들이 제안되었다. 이 중, 운영체제의 페이지 캐시에 대한 연구가 상반된 주장을 보이고 있는 점[11, 12, 13]에 착안하여 실험을 통해 이를 재확인하였다. 실험 결과, 큰 용량의 페이지 캐시가 SSD를 스토리지로 갖는 시스템에서 파일 입출력 성능을 크게 향상시키는 것을 확인 할 수 있었다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.2A
• /
• pp.12-19
• /
• 2005

The VoIP(Voice over IP) has been worldwide used and already put to practical use in many fields. However, it is needed to ensure secret of VoIP call in a special situation. It is relatively difficult to eavesdrop the commonly used PSTN in that it is connected with 1:1 circuit. However, it is difficult to ensure the secret of call on Internet because many users can connect to the Internet at the same time. Therefore, this paper suggests a new model of Internet telephone for eavesdrop prevention enabling VoIP(using SIP protocol) to use the VPN protocol and establish the probability of practical use comparing it with Internet telephone.