• Journal of IKEEE
• /
• v.5 no.1 s.8
• /
• pp.111-120
• /
• 2001

VC merging involves distinguishing cells from an identical merged VC label. Various approaches have been proposed to help this identification process. However, most of them incur additional buffering, protocol overhead and/or variable delay. They make the provision of QoS difficult to achieve. So it was proposed a merge capable scheduler to support VC-merging (VCMS). However, in situations where all VCs are to be merged or the incoming traffic load is very low, it could happen that there are not enough non-merging cells to snoop. In this situation the scheduler uses special control cells to fill the empty time slots out. Too many control cells can cause high cell loss ratio and an additional packet transfer delay. To overcome the drawbacks, we propose a Sequence Skipping(SS) method where the sequencers skip the empty queues and insert SS cells. We show SS method is suitable for VC-merging and can reduce the cell loss ratio and the mean packet transfer delay through simulations.

• Journal of Korea Water Resources Association
• /
• v.36 no.6
• /
• pp.1059-1068
• /
• 2003

Geographic Information System (GIS) combined with Universal Soil Loss Equation (USLE) was used to estimate the soil erosion of Asan Bay experiment watershed in Korea. Spatial data for each USLE factors were obtained from the Landsat-5 TM remote sensing images and 1/25,000 scale digital contour maps. Sediment yield to Asan Bay was estimated by the sediment delivery ratio and trap efficiency. The estimated sediment yield was compared with observed on the Asan and Sapgyo estuary sub-watershed within Asan Bay experimental watershed for the period from 1981 to 2000. The calculated total annual sediment yields from Asan and Sapgyo estuary sub-watershed to Asan Bay were 5,665tonnes/yr and 6,766tonnes/yr, respectively. The measured sediment yields were 12,937tonnes/yr and 12,395tonnes/yr, respectively on an average.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.26 no.3
• /
• pp.655-659
• /
• 2016

In this paper, we propose new detection and detour methods against packet drop attacks for availability in the Internet of Things (IoT) based on the IEEE 802.15.4e and RPL protocol standards that employ IPv6. We consider the rank value of RPL and the consecutive packet drops to improve the detection metrics, and also take into account the use of both sibling and child nodes on a RPL routing path to construct the detour method. Our simulation results show that the proposed detection method is faster than the previous result, and the detour method improves the detour success rate.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2010.05a
• /
• pp.774-778
• /
• 2010

Upland erosion pollutes surface waters and often causes serious problems when deposition occurs. This study builds a sediment rating curve using the measured sediment yield and the simulated soil erosion by a GIS-embedded empirical model. The coefficient of determination ($R^2$) between the simulated soil erosion and the measurement sediment yields with rainfall amount are 0.427 for Donghyang and 0.667 for Cheonchen, but the values with rainfall intensity are 0.873 and 0.927 respectively. The data are divided into two groups: one for calibration during 2002-2005 (48 months) and the other for estimation during 2006-2008 (36 months). The first data group (2002-2005) was used to derive the SDR with an aid of soil erosion calculated by the USLE and the measured sediment yield. The mean SDR with rainfall amount is 6.273 and 3.353, respectively, while 4.799 and 2.874 for rainfall intensity. But the standard deviation (STD) with rainfall intensity is 0.930 and 0.407, which is much less than that with rainfall amount (3.746 and 2.090) for both sites. The results show the derived SDR provides reasonable accuracy and rainfall intensity gives better performance in calculating soil erosion than rainfall amount.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2012.05a
• /
• pp.305-309
• /
• 2012

한국건설기술연구원의 주요사업인 "산지하천 유역의 홍수예측을 위한 수문조사(2011~2015년)"의 Test-bed 유역중의 하나인 설마천 유역(경기도 파주시 적성면)의 중류부에 위치한 사방교 수위관측소는 2011년 7월 중부지방의 집중호우에 의해 수위관측소가 유실되는 초유의 사태가 발생한 바 있다. 이에 따라 수위관측기기와 부대시설물이 모두 피해를 입었으며, 그 이후 수위관측소 운영이 중단되었다. 다만 유역출구인 전적비교 수위관측소는 일부분 피해가 있었으나, 정상적인 기능을 유지하여 결측이 없는 운영이 이루어졌다. 2011년 사방교 수위관측소의 수위관측 자료는 호우피해 발생 이전 관측자료 수집이 이루어진 2011년 7월 8일 13:30분까지 자료가 있으며, 그 이후는 호우피해에 의한 관측기기의 유실로 모두 결측이다. 따라서 본 연구는 2011년 7월 8일 13:30분 이후 관측이 이루어지지 못한 사방교 수위관측소의 유량자료를 모의 생성한 후 유역출구인 전적비교 수위관측소의 유량자료와 상 하류 유량 및 유출률 검토를 통하여 미관측기간의 결측자료를 최종 생성하였다. 최종 모의 생성된 유량자료는 2011년 이전의 유역의 수문학적 특성과 매우 유사한 경향을 보이므로 모의 생성된 결과는 매우 양호한 것으로 판단된다. 이러한 결과는 설마천 유역의 지속적인 운영과 아울러 6개 우량관측소의 우량자료와(2011년 7월 집중호우에 의해 1개 우량관측소 유실 발생), 유역출구인 전적비교 수위관측소의 신뢰성 높은 수위, 유량자료가 있었기에 가능한 일이다. 설마천 유역 수문자료는 홈페이지(http://seolmacheon.kict.re.kr)와 동시에 운영되는 '설마천-차탄천 수문정보시스템'을 통해 유역정보 및 자료를 저장하고 있으며, 제공을 통해 자료를 공유하고 있다.

• The Korean Journal of Pesticide Science
• /
• v.17 no.4
• /
• pp.256-263
• /
• 2013

The field lysimeter study was undertaken to investigate influence of agricultural practice and topography on runoff and erosion loss of fluazinam from the sloped land grown pepper. The WP type formulation was applied on July in 2003~2005. The wash-off rates were from 1.4% to 8.4% of the applied fluazinam. The runoff losses of fluazinam from a series of pepper grown-lysimeter plots were 0.14~0.90% in the first year, 0.01~0.04% in the second year and 0.16~0.37% in the third year for the mulched contour ridge plots, 0.47~1.59% for the mulched up-down direction ridge plots and 0.07~1.05% for the no-mulched contour ridge plots as the control, and they increased with slope degree. Concentrations of fluazinam in runoff water ranged mostly to 10 ${\mu}gL^{-1}$ at the first runoff event. Erosion rates from plots except the mulched up-down direction ridge plots was 0.00~0.21% for 10% and 20% slope-plots and 0.15~1.05% for 30% slope-plots with different slope degrees. Erosion rates from the mulched up-down direction ridge plots were 0.47~1.59% for 10% slope-plots and 0.75~1.05% for 20% slope-plots. Residues of fluazinam in soil at ten days after the application ranged from 0.007 mg $kg^{-1}$ to 0.059 mg $kg^{-1}$ except the soil under the mulch. After then the fluazinam residue in soil was dissipated at the rate of 20 days of half-life to below 0.01 mg $kg^{-1}$ at 60 days after the application.

• Asian Journal of Turfgrass Science
• /
• v.10 no.2
• /
• pp.143-150
• /
• 1996

The removal rates of gross production and organic matters were investigated in the Lake Paldangho. In 1995 and 1996, soils and litter sarraples were collected and annual mean production and removal rates were calculated. Communities in the Lake Paldangho were Phragrnites communis, Miscanthus sacchariflorus, Typha aegustata and Scirpas tahernaemoutani. Removal constants of aquatic plant communities estimated by the mathematical theoretical models, were 0.826, 0.567, 0.571 and 0.751, respectively. The durations of reaching half of initial organic amounts were 0.839 yeras, 1.221 years, 1.213 years and 0.922 years respectively at the steady state of removal and accumulation for organics For organics, the rapidity of removal were more speedy P. communis, S.tahernaemontani, T. augustata, M sacehariflorus in order. The times needed for 99% removal were 6.051 years, 6.651 years, 8.752 years and 8.811 years, respectively. Key wotds:Gross production, Organic matters, Lake Paldangho, Phragmites communis, Mis-ca ethus sacchariflorus, Typha angustata, Scirpus tahernaemoutani., Removal constants.

• Asian Journal of Turfgrass Science
• /
• v.10 no.2
• /
• pp.151-157
• /
• 1996

Samples from the L, F, H and $A_1$ horizons of the Phragmites communis, Miscanthus sacchariflorus, Scirpus tabernaemontani and Typha angustata grassland were collected in Paldangho and the removal rates of ritrogen were investigated. The removal rates of nitrogen of the litters were 0.85 in P.communis, 0.56 in M sacchariflorus, 0.45 in T. angustata and 0.31 in S. tabernaemontani The time required to decay 50, 95, 99 percent of the steady state levels and turnover values of nitrogen on the grassland floor were 0.81, 3.53, 5.89 years in the P. communis, 1.23, 5.32, 8.86 years in the M sacchariflorus, 1.54, 6.68, 11.13 years in the S. tabernaemontani and 2.22, 9.63, 16.04 years in the T. angustata Key words: Removal rate, Accumulation, Paldangho, Nitrogen, Phragmites communis, Miscanthus sacchariflorus, Scirpus tabernaemontani, Typha angustata.

• Asian Journal of Turfgrass Science
• /
• v.9 no.4
• /
• pp.343-350
• /
• 1995

Samples from the L, F, H and $A_1$ horizons of the Phragmites longivalvis grassland were collected in a delta of the Nakdong River and the removal rates of N, P, K, Ca and Na were investigated. The results obtained in this study can be abstracted as follows; The removal fractions of N, P, K, Ca and Na of the litter were 0.56, 1.22, 1.95, 0.65 and 0.53, respectively. The half times of N, P, K, Ca and Na required for the remove or accumulation of the litter on the grassland floor were 1.23, 0.57, 0.36, 1.06 and 1.32 years, respectively. The increasing order of the turnover parameters of the elements was Na, N, Ca, P and K.

• Asian Journal of Turfgrass Science
• /
• v.9 no.4
• /
• pp.331-342
• /
• 1995

An investigation was performed to reveal the removal rates of organic constituents of the litters in a Phragmithea longivalvis grassland in a Delta of the Nakdong River, The removal rates of the inorganic and organic materials are determined by the mathematical models. The removal rates and time required to decay up to a percentage of each organic constituent were calculated using these new models. The removal rates of cold water soluble fractions, other carbohydrates, hot water soluble fractions, cellulose, crude fat, lignin and crude protein were 2.67, 1.39, 1.25, 1.02, 0.92, 0.49 and 0.47, respectively, The periods required to reach half time to the steady state of the removal and accumulation for cold water soluble fractions, other carbohydrates, hot water soluble fractions, cellulose, crude fat, lignin and crude protein of the litter were 0.26, 0.50, 0.55, 0.68, 0.75, 1.41 and 1.48 years, respectively.