• The Korean Journal of Ecology
• /
• v.9 no.1
• /
• pp.51-58
• /
• 1986

The decay rates of organic matter were investigated and the leaching rates were determined from the concentration distribution of N,P,K, Ca and Na in the soil profile at Pinus rigida stand on Mt. Gwan-ak and at Pseudosasa japonica stand on Odong-do. In order to determine the leaching rates θo/W wazs substituted with KL in Towner's equation. Decay rates were 0.191 at Pinus stand on Mt. Gwan-ak and 0.234 at Pseudosasa stan don Odong-do. Concentration distributions of N,P, K and Na in soil profiles were corresponed with Towner's model curve. Leaching rates determined from concentration distributions were 0.086, 0.079, 0.041, 0.029, 0.096 on Mt. Gwan-ak and 0.080, 0.056, 0.051, 0.008, 0.028 on Odong-do. The soil of Pseudosasa stand showed on the whole lower leaching rates than that of Pinus stand. The soil of Pseudosasa stand showing higher decay rate and lower leaching rates contained more concentration of each nutrient than that of Pinus stand.

• Journal of Broadcast Engineering
• /
• v.5 no.2
• /
• pp.140-158
• /
• 2000

Testing of terrestrial Digital TV(DTV) broadcasting in Seoul and Kyung-gi region was started in May 1999. Tasks of the committee for DTV technical evaluation were to implement test procedures for DTV transmitting systems, to analyze various technical aspects of DTV and to complete a field test. This paper summarizes the field test results. The field test vehicle was designed and constructed to measure field data. We chose over 200 test points to verify the receiving status of DTV signals and compared them with the analog TV signals at the same site. The results showed stable and satisfactory reception of DTV signals over 70%. The system performance index was over 80%.

• The Korean Journal of Ecology
• /
• v.12 no.1
• /
• pp.9-20
• /
• 1989

Annual production and decomposition of litter were studied in piuns rigida platation in Mt. Kwan-ak. The peak time of litter production was October-November. The litterfalll at that time was 54% of annual litter production. But the peak time of litterfall of reproductive parts was Junejuly. The peak times of litter production in Alnus hirsuta plantation were June-July, and November. It is thought that difference of seasonal distribution of letterfall between two forest types were assigned to litter falling factors such as temperature and insects. Total amount of letter loss increased according to time. Particulary, the peak time of loss rate was July-August. It was shown that the protein and phosphorus were accumulated in the letter for an experimental period. The amount of crude protein increased to 150% of initial amount. The amount of potassium was increased by August and then decreased rapidly. The contents of crude fat, holocellulose, lignin, and Na were decreased slowly. The loss of holocellulose was the largiest among them. Calcium was in steady state. It was thought that this variation pattern was assigned to leaching of soluble parts by high temperature, rainfall and growth rate of microorganisms.

• Journal of environmental and Sanitary engineering
• /
• v.5 no.1
• /
• pp.28-33
• /
• 1990

The turnover rates of nitrogen(N), phosphorus(P), calcium(Ca), potassium(K), and sodium(Na) during the decomposition of litter were studied in the Pinus koraiensis forest in Choon Chun and in the Pinus rigida forest in Mt. Gwanak, Seoul. The turnover rates of N, P, K, Ca, and Na were 0.064, 0.068, 0.040, 0.417, and 0.058 for the P. korai ensis litter and 0.049, 0.049, 0.023, 0.346, and 0.058 for the P. rigida litter respectively. The loss of elements follows the order Ca>P>N>Na>K in the P. koraiensis litter and the order Ca>Na>N=P>K in the P. rigida litter. Generally the turnover rates of cations were greater than those of anions.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.05b
• /
• pp.562-566
• /
• 2005

본 연구에서는 레이더 자료의 수문학적 적용성에 대한 정확도를 개선하고자 기상현업에서 운영하고 있는 관악산 도플러 레이더 자료를 활용하여 POD(Probability of Detection) 분석을 통해 레이더 오자료를 제거하고, 편차 보정기법을 적용하여 레이더 추정강수의 정확도를 개선시켜 이들의 수문학적 적용성을 검토하였다. 이를 위해 다양한 관측 고도각 별로 POD 분석을 수행한 결과 낮은 확률의 POD($p_l$)와 높은 확률의 POD($p_h $)의 범위가 변화하고, 레이더로부터 약 150 km 이상 떨어진 지역에서는 $1.95^{\circ}$ 이상의 고도각에서 탐지한 레이더 에코가 강수 추정에 유용하지 않음을 알 수 있었다. 또한 소양강유역을 대상으로 관측 강우량보다 과소추정되는 Marshall-Palmer 관계식의 레이더 추정강수를 편차 보정기법으로 실시간으로 보정하여 그 정확도를 향상시켰다. 보정된 레이더 추정강수를 HEC-1에 적용하여 유량해석을 수행한 결과, 보정된 레이더 추정 강수를 이용한 모의치와 관측유량사이에 매우 높은 상관성을 보이고 있음을 알 수 있었다. 따라서 편차 보정기법을 통해 보정된 레이더 강수는 수문학적 분석을 위한 입력자료로 유용하게 사용될 수 있을 것으로 판단된다.

• Journal of Korean Society for Atmospheric Environment
• /
• v.10 no.1
• /
• pp.41-48
• /
• 1994

A monitoring system for atmospheric CFC-12 and CFC-11 has been established at Mt. Kwan-Ak, Seoul National University (SNU) since July, 1991. The concentrations showed quite a large variation ranging from 495 to 37600 pptv (pptv=part per trillion, 10$^{-12}$ , v/v) for CFC-12 and from 233 to 12100 pptv for CFC-11 due to many local sources. However, monthly medians show rather limited ranges ; 553~765 pptv for CFC-12 and 301~431 pptv for CFC-11. Furthermore minimum concentrations could be defined relatively well during the whole period of observation. The regional background concentrations in 1993 near SNU wer estimated as 533 pptv for CFC-12 and 293 pptv for CFC-11. These values are very comparable to global averages in Northern Hemisphere, 523 pptv for CFC-12 and 287 pptv for CFC-11, reflecting the fast atmospheric mixing processes within the hemisphere. Examinations with meteorological parameters such as wind speed and direction suggest the possible measurement-window at SNU, appropriate for regional monitoring. Studies for improving the monitoring capability of the SNU station such as automation of the analysis system along with correlation with other meteorological parameters, are in progress at the present time.

• Journal of Broadcast Engineering
• /
• v.7 no.3
• /
• pp.271-276
• /
• 2002

It is very important to find errors in broadcasted streams because it can help us to find where errors occur. Broadcasted streams may have errors in the RF(radio frequency) or baseband domain. It is very important to fix these errors because it can help to stabilize set-top boxes, provide stable receiving, and give comfortable environments to watch TV. Since 2001, major terrestrial broadcasters in Korea started the DTV broadcasting in Kwan-Ak over Seoul area. In this paper, we provide some analysis on errors in MPEG-based TS streams, PSIP packets, and RF area which may occur in DTV systems and compare this result with that of USA.

• 한국방재학회:학술대회논문집
• /
• 2011.02a
• /
• pp.174-174
• /
• 2011

강우의 공간적 변동성을 파악하기 어려운 우량계 관측방법의 한계를 극복하기 위한 방법으로 레이더를 이용한 강우관측이 주목받고 있다. 레이더는 실시간으로 넓은 지역의 강우 현황을 파악하는 것이 가능하므로 강우 예측에 있어 매우 큰 장점을 갖는다. 그러나 레이더를 통해 관측된 강우는 실제값을 의미하지는 않는 것이 사실이다. 이에 본 연구에서는 레이더 및 우량계 강우자료가 대수정규분포를 따른다고 가정하는 경우의 편의보정 문제를 살펴보았다. 이를 위해 대수정규분포를 따르는 자료에 대한 평균값, 중앙값 및 최빈값에 대한 회귀선을 유도하여 검토하였다. 본 연구에서는 2003년에 발생한 태풍 매미로 인해 발생한 강우 사상이 대상 호우사상으로 적용되었으며, 이에 대한 강우자료는 관악산 레이더 강우 자료와 레이더의 관측 반경 내 존재하는 국토해양부 산하 127개 우량계 시강우 자료이다. 그 결과, 독립변수로 사용된 강우자료에 따라 그 차이가 매우 큰 것으로 나타났다. 독립변수로 레이더 강우를 사용한 경우에는 G/R 보정된 레이더 강우의 과소추정 문제가 나타날 것으로 보인다. 반대로 우량계 강우를 독립변수로 한 회귀선에서는 레이더 강우의 보정결과가 어떻게 나타날지는 뚜렷하지 않다. 따라서 위와 같은 회귀선을 통해 보정한 레이더 강우의 검토가 추가적으로 필요할 것으로 보인다. 그러나 이 경우에서는 독립변수로 레이더 강우를 사용한 경우에서 나타나는 레이더 강우의 과소추정 문제가 어느 정도 극복될 것으로 보인다. 아울러 일반적으로 적용되고 G/R 보정계수에 대한 검토 및 이에 대한 비교가 또한 필요할 것으로 판단된다.

• Atmosphere
• /
• v.18 no.3
• /
• pp.225-235
• /
• 2008

Sulfur hexafluoride ($SF_6$), man-made compound, has been paid attention as a potent greenhouse gas. After Kyoto Pototcol on Climate Change in 1997, nations established the policy aimed at minimizing release of $SF_6$ to atmosphere. We have developed and operated an automatic analytical system for monitoring atmospheric $SF_6$ using gas chromatography with electron capture detector (GC-ECD) and packed separate-column. Here, we report and discuss 4-month record of atmospheric $SF_6$ concentrations monitored at Seoul National University (SNU) pilot station near the Kwanak Mountain, Seoul. Most of observed $SF_6$ concentrations were excessively high compared with Northern Hemisphere (NH) background trend obtained from National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory (ESRL) monitoring stations. And the observed $SF_6$ showed extremely wide variability ranging from 4.6 pptv to $1.1{\times}10^3$ pptv, which may be affected by local sources placed nearby. Simultaneous wind data with $SF_6$ measurements show that relatively high values of $SF_6$ correspond to weak wind as well as southerly. There are many engineering installations to the south of the station. The regional value of the atmospheric $SF_6$ estimated from the data selection by wind conditions is about 6.8 pptv. This value, which is similar to concentrations of urban areas, is higher than NH background concentration.

• KIEAE Journal
• /
• v.6 no.4
• /
• pp.3-10
• /
• 2006

To preserve scenic-view of Gwanak Mountain from the urban development, the viewshed component ratio and the scenic-view preference are investigated and analyzed by selecting view points at Nangokro. After 16 candidate view points are selected from the site, sight component ratio is measured through visual structure analysis and preference are measured by using the Likert scale. In addition, factor analysis, and regression analysis were conducted to examine the relationship between influencing factors and preference. As a result of the regression analysis of the 9 factors to influence the scenic-view preference, two factors such as degree of natural landscape and degree of arrangement around the site are chosen to influence the scenic-view preference. Through the preference factor analysis, two preference factors are selected as follows; 1) The factor of the landscape formation - Existence and nonexistence of the scenic-view conservation, degree of the landscape opening, and degree of natural landscape, degree of the landscape originality, and degree of the landscape sequence, degree of the landscape intimacy 2) The factor surrounding the landscape - Degree of arrangement around the site, degree of the landscape complexity, and atmosphere around the site.