• Journal of Korean Tunnelling and Underground Space Association
• /
• v.17 no.4
• /
• pp.415-428
• /
• 2015

With increase of the extension of long tunnels and urban tunnelling, demands on the new tunnelling technologies are raised. Currently, drilling and blasting tunnel construction method is mostly used, however, because of sever blast vibration for some occasions, complaints from local residents and rock damages are inevitable. Accordingly, TBM tunnelling is more efficient and effective for such conditions. Nevertheless, tunnel construction costs of TBM cannot compete that of the drill and blasting method in Korea. To overcome such limitations, various TBM equipments and construction technologies are required. In addition, continuous revision of the design standard and specification are required. In this study, a detailed explanation regarding the revised version of TBM section in the tunnel standard specification at 2015 is shown.

• Journal of the Korean Chemical Society
• /
• v.45 no.2
• /
• pp.177-182
• /
• 2001

An instructional model using multiple analogies according to component process (MACP) was designed on the vasis of schema theory and comornent process theory in analogical reasoning. This model has ？ phases: introducting multiple analsgs, extracting multiple analogs, extracting common attributes of analogs, introducing target conanother context. Te instructional effects of this model upon students' conceptual understanding and learning motivation were compared with those of the Teaching-With-Analogy (TWA) and non-analogy instructions. Three classes of 8th grade were randomly assigned to MACP, TWA, and control group, respectively, Subjects were taught about chemical changes and reactions for 10 class hours. The ANCOVA results indicated that the scores of the conceptions test for the MACP group were significantly higher than for the control graup. However, no significant differences were found among the three groups in the test scores of learning motivation.

• Korean Journal of Environment and Ecology
• /
• v.15 no.2
• /
• pp.118-124
• /
• 2001

본 연구의 목적은 도식에 식재된 두 침엽수조인 소나무와 잣나무 단목의 연간 $CO_2$, $SO_2$, $NO_2$ 흡수 및 $O_2$ 생산을 계량화하는 것이다. 자연환경 조건하에서 운반형 적외선가스분석기로 연간 $CO_2$교환율을 측정하여 $CO_2$흡수 및 $O_2$ 생산량을 그리고 $CO_2$와 SO$_2$EH는 $NO_2$간 흡수속도비를 적용하여 $SO_2$ 및 $NO_2$흡수량을 각각 산정하였다. 흉고직경을 독립변수로 단목의 생장에 다른 연간 $CO_2$흡수 및 대기 정화량을 추정하는 활용 용이한 방정식을 유도하였다. 연구대상 수목 중, 흉고직경 20cm인 잣나무는 연간 양 35kg의 $CO_2$, 11g의 $SO_2$, 19g의 $NO_2$를 각각 흡수하였고 25kg의 $O_2$를 생산하였다. 동일 직경의 소나무는 유도한 방정식을 적용하면, 연간 약 30kg의 $CO_2$, 9g의$ SO_2$, 15g의 $NO_2$를 각각 흡수하였고 22kg의 $O_2$를 생산하였다. 생상기간 중 단위엽면적당 $CO_2$흡수량은 잣나무가 소나무보다 적었으나, 단목의 연간 $CO_2$흡수 및 대기정화량은 총엽면적의 차이로 잣나무가 동일 직경의 소나무보다 많았다. 본 연구결과는 도시 침엽수의 연간 대기정화 가치를 용이하게 계량화학고 도시공간내 수목식재의 환경적 중요성을 홍보하는데 활용될 수 있다.

• Journal of Educational Research in Mathematics
• /
• v.15 no.4
• /
• pp.401-417
• /
• 2005

Skemp supposed that it is effective to use both examples and non-examples when new concepts which are upper level than learner's schema are introduced. The purpose of this research is to develop a practical process of teaching geometrical concepts based on Skemp's assumption. For this, the related literatures are reviewed and the Korean textbooks(4-ga, 4-na) are analyzed with respect to method of concept formation. The analysis to]Is that the textbook just explains Properties of concepts or present definitions, instead of giving the chance of inquiry. So we design and apply six step process of teaching geometrical concepts to 4th graders focused on students' inquiry using both examples and non-examples.'rho result turns out that using examples and non-examples is highly positive to concept formation.

• Journal of Korean Society of Steel Construction
• /
• v.11 no.3 s.40
• /
• pp.251-258
• /
• 1999

The aim of this paper is to examine the behavior of the N-joints using square hollow sections and to improve the structural performance without reinforcing the joints. The selected parameters are the ratio of web to chord width, gap to chord width and eccentricity to chord width. Comparison between test results and codes shows the fact that the NPE-type has superior structural properties to the NSE-type in ultimate strength and deformation capacity. The experimental formulae based on the regression analysis are proposed. Ultimate strength formula employed in eurocode 3 is revised and proposed for the NSE-type. And ultimate strength formula including the eccentricity to chord width ratio which effects on the ultimate strength is proposed for the NPE-type.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2011.05a
• /
• pp.352-352
• /
• 2011

최근 이상기후 및 집중호우 등의 영향으로 국지적으로 큰 강우가 발생하여 재산피해 및 인명피해를 발생시키고 있으며, 과거 강우발생 빈도에 비하여 큰 강우가 발생되고 있다. 이러한 증가되는 추세에 대하여 확률강우량 산정시 반영하고 있는 추세이며(한만신, 2005), 이렇게 반영된 결과는 확률강우량의 증가와 함께 설계시 반영되어 안전하게 수공구조물을 시공하게 된다. 하지만, 이러한 강우의 경향을 단순하게 증가추세로만 판단하여 미래의 강우를 증가라는 개념으로 검증 절차없이 도입하기에는 과대 추정될 우려가 있으며, 과대 추정된 확률강우량은 결국 시공비의 증가를 유도하여 경제적으로 불이익이 발생한다. 따라서, 과거의 강우자료를 통하여 분석된 최근의 강우 예측결과가 어느정도의 타당성을 갖고 설계된 것인지 판단하여 향후 강우 예측을 통한 확률강우량 산정시 반영하여야 할 것으로 판단된다. 본 연구에는 강우 예측을 위하여 사용되고 있는 ARIMA 모형을 이용하여 인천지역의 1961년~2005년까지의 강우자료를 이용하여 2010년까지의 강우를 예측함으로써 실제 강우자료와의 비교를 통하여 강우 예측의 신뢰성을 검토하여 미래 강우에 대한 예측에 있어서 보다 신뢰성을 확보하고자 하였다. 또한, 강우추세에 의한 인천지역의 확률강우량을 산정함으로써 동일 유역에서의 다른 분포형이나 확률강우를 사용함으로써 발생되는 설계의 혼란을 방지하고자 한다. 본 연구를 위하여 인천지방 기상대의 관측자료를 이용하여 1961년부터 2010년까지의 분단위 강우자료를 획득하였으며, 임의시간에 의한 지속시간별 최대강우량을 산정함으로써 기존의 설계에서 사용되어 왔던 고정시간의 환산계수 대신 실제 최대강우량을 이용함으로써 강우 예측에 대한 정확도를 향상하였고, 확률강우강도식 선정시 지역 강우 특성을 고려하여 결정하여야 한다는 결론을 도출하였다.

• Journal of Korea Water Resources Association
• /
• v.33 no.1
• /
• pp.3-14
• /
• 2000

The primary objective of this study is to estimate the suitable flow in need for conservation and restoration of the fish habitat in running water ecosystem, which has very important status in the instream flow for stream environment. Year, monthly low flows are estimated to properly maintain the fish habitat. Water depth and velocity are simulated, and also water temperature and Dissolved Oxygen(DO) are predicted at gradually varied flow using estimated low flows. These simulated conditions for each low flow are graphically compared with the requirements to maintain fish habitat at each life stage. These processes were applied to 3 riffle transects located at Dalcheon(Dal stream) in the South Han river. Pirami (Zacco platypus) was selected as a representative fish species in Dalcheon. It was shown that the suitable flow for maintaining the representative fish habitat at each life stage depends on hydraulic conditions rather than water quality conditions, and the flow ranges from the 10-year minimum low flow to consecutive 7-day 2.33-year low flow.w flow.

• Korean Journal of Microbiology
• /
• v.38 no.4
• /
• pp.276-280
• /
• 2002

To find the applicability of resemblance of the fatty acid methy1 ester (FAME) profile analysis to the primary examination for the tracing P. aeruginosa contamination in the environment and water plants, we designed this study. Of6l P. aeruginosa isolates including 3 reference strains, 4 fecal or soil isolates and 54 water isolates, the resemblance coefficiencies of the FAMEs were calculated as euclidian distance (ED) and expressed as dendrogram. The 61 strains were clustered as the same group in the ED 8.4, and divided into 4 subgroups in the ED 6.9. The water isolates from Han River were classified into distinctively different subgroups from reference strains. These results provide the possibility of the dendrogram from FAME profile as a useful tools for tracing contamination as well as for identifying the species, especially in case of P. aeruginosa.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.11A
• /
• pp.1059-1065
• /
• 2010

Recently, analog broadcasting are being converted into digital radio broadcasts, Among the various ways that HD Radio is a candidate for the U.S. approach, Digital Radio will transmit a digital signal to existing analog FM/AM. It provides clear sound quality, traffic information, weather information and various value-added services. In addition, the converted digital radio will be able to meet demand to growing demand for analog FM. In this paper, Digital FM Radio system in the same frequency band using electric field strength of the received digital radio broadcasting interference effects were analyzed. And Digital FM Radio Receiver interference effects were analyzed by interference signal power and signal power. Results were confirmed by applying equation at minimum field strength and SNR.

• Journal of the Korean Geographical Society
• /
• v.36 no.1
• /
• pp.15-34
• /
• 2001

This is the second segment of an action research on the constructivist geography education.(1)Deeper and lasting construction of knowledge may be possible especially when some key or leading concepts are utilized, around which other related concepts may be further explored. (2) Graphic languages may be more pedagogically effective than any other language, when they are viewed as means of learning may be the teacher's questioning, cooperative discussion, and the teacher's guidance and assistance. The questioning by the teacher seems effective when it is appropriate to the different levels of learner's comprehension, and cooperative discussion among thern seems productive with the teacher's attentive guidance. And, (5) constructivism may best be understood when teachers try to embody it in their own classrooms. This may be part of the context in which action research is called for.