• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.05b
• /
• pp.1328-1332
• /
• 2005

본 연구는 경안천유역의 최적 수질 측정망 구성을 위하여 분석을 수행하였다. 분석을 위해서 필요한 수질데이터는 Qua12e 모형을 이용하여 모의하였으며, Kriging과 최적화 기법인 Branch & Boundary 방법을 이용하여 최적화된 수질 측정지점을 제시하였다. 또한 측정횟수는 신뢰구간과 유의수준을 고려하여 Proportional Sampling 방법을 적용하였다. 적용 결과 경안천에는 21개의 측정지점이 적합한 것으로 판단되며, 측정 빈도는 1년간 유량을 월별로 구분 하였을때 상위6달의 경우는 한달에 $1\~3$회, 하위 6달은 $1\~4$회를 측정하는 것이 적합하다는 결론을 얻었다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2001.10c
• /
• pp.172-174
• /
• 2001

본 논문에서 는 WAN 환경 에 서 의 선도시험망 기반 QoS테스트베드를 구성하고 차등화 서비스에 의한 QoS의 성능을 측정하였다. 전송율. RTT. 패킷 손실, FTP 소요시간을 대상으로 QoS 보장 서비스와 베스트-에포트 서비스에 대한 성능을 비교 분석하였다. 모든 측정 대상에 대하여 QoS 보장 트래픽이 좋은 성능을 보여주었으며, 특히 멀티미디어 어플리케이션의 비디오 트래픽에 대해서도 QoS 보장 서비스에 의한 전송서비스가 고품질의 영상을 제공하였다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2003.04d
• /
• pp.280-282
• /
• 2003

본 연구에서는 HFC망에서 음성 통화품질에 영향을 주는 파라미터들에 대한 분석과 측정을 통해 VoIP의 특성을 파악하여 향후 본격적으로 이루어질 인터넷을 통한 음성 서비스 제공에 대비하였다 특히, VoIP QoS 기준의 정의는 QoS 파라미터의 분석을 토대로 한 lab 테스트와 HFC VoIP 서비스의 필드 측정을 병행하여 연구 결과에 대한 실질적 서비스 적용에 따르는 신뢰성을 높였다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2007.11a
• /
• pp.1104-1107
• /
• 2007

본 연구는 디지털 방송망을 관리하기 위해 디지털 장비들을 네트워크로 연결하고 이를 원격으로 제어하여 측정결과를 자동으로 수집하며, 데이터 베이스를 이용하여 이를 관리하며 마이크로소프트사의 엑셀 및 워드와 같은 문서로 보고서를 자동으로 작성하는 통합측정 및 관리 시스템을 개발하고자 한다.

• Journal of Korea Soil Environment Society
• /
• v.4 no.2
• /
• pp.45-53
• /
• 1999

The soil samples were measured at 90 sites of Soil's Network In 1997~1998 which was established for the investigation of soil contamination in Seoul. This study was more focused to measure and analyze for BTEX(Benzene, Toluene, Ethylbenzene and Xylene) concentration in the Soil Network. Also, the samples were analyzed by Purge & Trap method. As a result, the BTEX were detected at all sampling sites in Seoul. The Min. Max and Mean BTEX concentration were respectively 0.047mg/kg, 2.618mg/kg and 0.437mg/kg in 1998. The concentration of the BTEX detected at all sampling sites was lower than that of the intervention standards(at industrial areas) of Soil Preservation Act.

• The KIPS Transactions:PartC
• /
• v.12C no.3 s.99
• /
• pp.437-442
• /
• 2005

The measurement of RTT (Round Trip Time) can be used for the analysis of Internet congestion. However, simple measuring of RTT which measures only hun around time of a packet can not infer a packet forward/backward delay variation. In this thesis, we present a new algorithm which can be used for the estimation of forward/backward delay variation of packets. These delay variations are implication of network congestion state. In this algorithm, the reference forward/backward delay can be determined based on the minimum RTT value. The delay variation of each packet can be calculated by comparing reference delay with the packet delay. We verified our proposed algorithm by NS-2 simulation and delay measuring in a real network.

• Journal of the Korean Society for Railway
• /
• v.12 no.6
• /
• pp.902-908
• /
• 2009

TETRA is the standard of Digital Trunked Radio System developed by the ETSI (European Telecommunications Standards Institute). It is currently adopted as Electric Power IT Wireless Backbone Network in Korea, and a national enterprise is going on for versatile utilization of TETRA. To use TETRA wireless network, TETRA modem is very necessary such that performance measurements are very crucial for each TETRA modem by various manufacturers. In this paper, PED (Protocol Evaluation Data) is suggested for PD performance measurement in D-TRS wireless network environment. The performance measurements for different data lengths and transmission intervals are done using TG (Traffic Generator) on Test Bed. The data size is increased by 10 bytes from 10-byte to 400-byte, and it is measured 1,000 times for each transmission interval of 0.5, 1.0, and 1.5 seconds. Based on the transmission time measured, average transmission speed and MER (Message Error Rate) are derived for TETRA Modem performance measurement. Two TMR880i's of EADS are used for TETRA modem, and SwMI (Switching and Management Infrastructure) of EADS is used for switching system in this paper.

• Journal of Korea Soil Environment Society
• /
• v.1 no.1
• /
• pp.55-65
• /
• 1996

Soil quality of most of Soil Network area was estimated healthy by employing Soil Pollution Indices (Soil Pollution Score and Soil Pollution Class). However, 1.5∼3.7% of the total Soil Network area was determined Soil Pollution Class (SPC) 4 which may need cleanup process due to slight or heavy pollution with arsenics and heavy metals. Numbers of the SPC 4 sites were 9, 47, 19, 17, and 17 in 1987, 1989, 1991, 1993, and 1994, respectively During 1987 and 1994, all of SPC 4 sites were identified agricultural land except one in 1994. Soil Pollution Scores (SPSs) was determined high around smelters, metalliferous mines, and industrial sites among the 16 major soil pollution sources of the Soil Network. Also, most area of SPC 4 sites were densely populated in these area of the Soil Network. SPSs of Inchon and Taegu were high among the other major cities and provinces in Korea. Numbers of SPC 4 were high in the province of Kangwon, Kyongbuk, Kyongnam amongst. Cumulative numbers of SPC 4 multiplied by a weighting value 0.3 during 1987 and 1994 of the Soil Network were regressed to develop a model equation for prospecting the soil quality. The model equation was Y= 1.16+0.23x, where as Y is the number of Class 4 and x is the year. Resulting the area of SPC 4 were 4.8%, 6.0%, 6.6% of the Soil Network in the year of 2001, 2006, 2011, respectively Based on this results, the area of SPC 4 would increase 5, 7, and 10 times comparing the area polluted with heavy metals in 1987.

• Journal of Korea Technology Innovation Society
• /
• v.7 no.2
• /
• pp.441-458
• /
• 2004

이동망의 착신접속서비스는 각국에서 bottleneck 서비스로 인식하고 규제당국에서 원가에 근거하여 규제하고 있다. 원가에 의한 규제 방식으로 과거에는 회계자료를 근거로 한 역사적 원가가 사용되어 왔으나 최근에는 유선망의 경우처럼 bottom-up 방식의 장기증분원가(Long Run Incremental Cost ： LRIC)를 적용하는 사례가 증가하고 있다. LUC를 산정하기 위해서는 공학적인 기준에 따라 이동망을 설계하여 정확한 망 구성요소별 소요량을 측정하고 이를 투자비로 전환하는 작업이 필요하다. 유선망의 경우는 LRIC산정을 위한 망 설계방법론이 비교적 잘 확립되어 있으나, 이동망의 경우는 망 설계 및 망 구성요소별 소요량 산정방법론에 대한 연구가 부족한 실정이다. 본 고에서는bottom-up방식의 이동망 LRIC산정관련 해외 사례를 살펴보고 국내 실정에 적합한 이동망 설계 방법과 망 구성 요소별 소요량 산정 방법론을 제시해보고자 한다.

• Sleep Medicine and Psychophysiology
• /
• v.25 no.2
• /
• pp.82-91
• /
• 2018

Objectives: Synchronous electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) has been used to explore sleep stage dependent functional brain networks. Despite a growing number of sleep studies using EEG-fMRI, few studies have conducted network analysis on whole night sleep due to difficulty in data acquisition, artifacts, and sleep management within the MRI scanner. Methods: In order to perform network analysis for whole night sleep, we proposed experimental procedures and data processing techniques for EEG-fMRI. We acquired 6-7 hours of EEG-fMRI data per participant and conducted signal processing to reduce artifacts in both EEG and fMRI. We then generated a functional brain atlas with 68 brain regions using independent component analysis of sleep fMRI data. Using this functional atlas, we constructed sleep level dependent functional brain networks. Results: When we evaluated functional connectivity distribution, sleep showed significantly reduced functional connectivity for the whole brain compared to that during wakefulness. REM sleep showed statistically different connectivity patterns compared to non-REM sleep in sleep-related subcortical brain circuits. Conclusion: This study suggests the feasibility of exploring functional brain networks using sleep EEG-fMRI for whole night sleep via appropriate experimental procedures and signal processing techniques for fMRI and EEG.