• Journal of the Korea Society of Computer and Information
• /
• v.14 no.8
• /
• pp.97-106
• /
• 2009

ABEEK, an independent non-governmental organization, is the recognized accreditor for the educational programs in engineering and related disciplines. ABEEK has developed the standard accreditation criteria to meet diverse needs of the engineering and related communities in Korea. A student attending at the accredited program has to complete the required courses and elective courses according to the curriculum flowchart to meet the accreditation criteria for a bachelor. Therefore an efficient and effective tool is necessary to support the adviser to monitor the completion of the required courses and elective courses according to the curriculum flowchart. In this paper, we describe an adviser tool developed. To develop an adviser tool. we established databases which contain the information of courses and their relations according to the curriculum flowchart. Adviser tool was developed to analyze student's DegreeAudit and represent the current completion information on the curriculum flowchart for effective monitoring. A closed test was performed and showed the increase of efficiency to meet the accreditation criteria for a bachelor.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.14 no.3
• /
• pp.261-275
• /
• 2012

This paper presents numerical analysis of the mud cake infiltration behaviour which is influenced tunnel face stability during excavation by slurry shield TBM. This analysis method can make useful data to select proper shield TBM type and to set up the construction plan. But effective analysis did not proposed until now. In this paper, we carried out numerical analysis using by $PFC^{2D}$ fluid coupling simulation which is suitable for sandy soil modelling. As a analysis result, we checked that the slurry infiltration behaviour varied with soil permeability and slurry characteristic(specific weight, viscosity etc). This analysis method is helpful safety excavation through anticipating the proper slurry viscosity at the design stage and verifying the slurry quality at initial excavation stage.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2021.06a
• /
• pp.30-30
• /
• 2021

우리나라 수리시설물 중 30년 이상 경과된 수리시설물은 전체의 61%를 차지하며, 특히 저수지의 경우 저수지의 약 84% 정도는 50년 이상 된 노후 저수지로 분류되고 있어 지속적인 보수·보강 필요하며 향후 기후변화에 취약할 것으로 예상된다. 이수측면에서 설계기준이 되는 설계한발빈도는 농업용 저수지의 내한능력을 나타내는 것으로 수리시설의 규모를 결정하는 기준이 된다. 국내의 경우 1982년 농지개량사업계획 설계기준 댐편에 한발빈도 10년 기준을 채택하여 사용되고 있으며, 현재 농업용 저수지의 이수안전도는 한발빈도 설계기준을 대신하여 사용하고 있다. 농업용 저수지의 이수안전도는 기존 설계기준에 의한 물수지법에 따른 저수지의 설계빈도로 산정되어 기후 및 영농변화, 용수수요의 변화, 농법의 변화 등 현장의 물관리 여건을 반영하는데 한계가 있다. 실제 저수지의 이수능력은 한발빈도 설계기준으로 대변되는 공급가능량 및 평야부 용배수로의 형상에 따라 농업용수 공급역량이 상이하므로, 평야부를 포함하는 농촌유역, 농촌공간의 이수안전도 개념이 도입되어야 한다. 또한 국가의 유관기관들은 특성 및 용도에 맞는 용수공급 정보를 생산하여 모니터링 자료를 제공하고 있지만, 실제 현장에서 체감하는 물 부족 및 이수관련 문제 해결을 위해 현장기반 데이터 활용이 필요하다. 본 연구에서는 기존 경험에 의한 관행적인 물관리 자료, 저수지 관련 계측 자료, 위성영상 자료, 비정형 미디어 데이터 등 이수 관련 분야의 빅데이터를 통합 구축하여 농촌유역 이수안전도의 개념을 정의하고자 한다.

• Journal of Bio-Environment Control
• /
• v.18 no.4
• /
• pp.481-491
• /
• 2009

This study was conducted to observe some characteristics of aneuploid trees obtained from the crosses between diploid and triploid in the first experiment. The results showed that the difference among the percentage of aneuploid's pollen grain germination was large, and all of them were lower than that of diploid 'Hongro' (82.4%). The average weight and size of each aneuploid's fruit was far lighter and smaller than that of diploid 'Hongro'. According to the width and length, all of the fruits shape was flat or short-globose conical shape except for JF3942. Almost all the aneuploid had higher sugar content than 'Hongro', nearly half of aneuploid fruits were firmer than that of diploid 'Hongro'. As for the acid contents of aneuploid fruits, the results were greatly different from those of previous studies on diploid apples, in present study the citric acid and tartaric acid contents were more than the malic acid which are dominant acid in most cultivars of apples. Both the length and width of aneuploid tree were shorter than that of diploid 'Hongro'. Most aneuploid trees' height was longer than width, but there were 4 exceptions. The size of leaves was smaller than that of diploid 'Hongro' according to the length and width of leaves measured. In all, aneuploid's vegetative growth is not as vigorous as diploid.

• Applied Chemistry for Engineering
• /
• v.8 no.5
• /
• pp.822-829
• /
• 1997

When $Al_2(SO_4)_3$ as an accelerator was added to $\beta$-hemihydrate gypsum, the setting time, mobility and compressive strength properties of $\beta$-hemihydrate gypsum were examined with the adding of two types grounded gypsum crushed by ball mill. By 15wt% adding of 7% $Al_2(SO_4)_3$ dilute solution, the setting time of $\beta$-hemihydrate gypsum was sharply accelerated than that of non-added $\beta$-hemihydrate gypsum. When ground phospho gypsum(PG) and chemical gypsum(CG) were added to $\beta$-hemihydrate gypsum, the initial and final setting time of $\beta$-hemihydrate gypsum were accelerated markedly with the increasing of grinding time and added amount of ground phospho gypsum. Especially, this trend largely presented when ground phospho gypsum was added to $\beta$-hemihydrate gypsum. The compressive strength of $\beta$-hemihydrate gypsum added by ground phospho and chemical gypsum was largely increased at initial curing time such as 1, 3 days. Particularly, the compressive strength of $\beta$-hemihydrate gypsum added by ground phospho gypsum was increased by 15~20% than that of ground chemical gypsum.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.512-512
• /
• 2022

국내 수자원 시스템은 이수 관련 기준과 이를 평가할 수 있는 지표 및 방법, 지침이 미흡한 실정으로 관련 시설물의 안정성과 형평성에 대한 문제가 제기되어 왔다. 농업용 저수지의 경우 한발 시 관개용수를 공급할 수 있는 내한능력, 기존 설계기준에 의한 물수지법에 따른 저수지의 설계한발빈도를 대체 사용하여 이수안전도를 산정하고 있으며, 설계한발빈도인 10년 한발빈도는 10년에 1회 정도의 갈수를 기준으로 한다. 농업용 저수지의 축조년도는 1940-1970년대로 약 86%가 축조된 지 50년 이상 경과하였고, 대부분 설계 한발빈도가 10년 이하로 축조되었으나 최근 발생하고 있는 기후변화, 용수관리 환경 변화, 수요량의 변화, 설계한발빈도 변화 등으로 현시점의 이수안전도 파악이 필요한 실정이다. 본 연구에서는 국가물관리기본계획에서 준용하고 있는 신뢰도 관련 이수안전도 기준인 이수안전율과 공급신뢰율을 활용하여 농업용 저수지의 이수안전도를 산정하고 기존 농업용 저수지의 이수안전도 기준인 10년 한발빈도와 비교함으로써, 농업용 저수지 이수안전도 산정기준의 적정성을 평가하고자 한다. 신뢰도 기준은 장기간 계획기간 동안 저수지의 용수부족이 얼마나 발생하는가에 대한 평가 방법으로 이수안전율은 최대 부족량과 수요량으로 산정가능한 양적기준 신뢰도이며, 공급신뢰율은 물공급부족기간으로 산정가능한 시간기준 신뢰도이다. 신뢰도 기준에 의한 방법은 저수지 모의 운영을 통한 물수지 분석을 실시하여 산정이 가능하며, 물수지 분석을 위해 한국농어촌공사에서 개발한 수리수문설계시스템 (K-HAS, Hydraulics & Hydrology Analysis System)을 사용하였다. 본 연구의 결과는 농업용 저수지의 이수관리 계획 수립 및 내한능력 평가 등 국가수자원정책의 지표로 활용할 수 있을 것으로 기대된다.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.13 no.4
• /
• pp.347-370
• /
• 2011

Slurry type shield would be very effective for the tunnelling in a sandy ground, when the slurry pressure would be properly adjusted. Low slurry pressure could cause a tunnel face failure or a ground settlement in front of the tunnel face. Thus, the stability of tunnel face could be maintained by applying an excess slurry pressure that is larger than the active earth pressure. However, the slurry pressure should increase properly because an excessively high slurry pressure could cause the slurry flow out or the passive failure of the frontal ground. It is possible to apply the high slurry pressure without passive failure if a horizontal impermeable layer is located in the ground in front of the tunnel face, but its location, size, and effects are not clearly known yet. In this research, two-dimensional model tests were carried out in order to find out the effect of a horizontal impermeable layer for the slurry shield tunnelling in a saturated sandy ground. In tests slurry pressure was increased until the slurry flowed out of the ground surface or the ground fails. Location and dimension of the impermeable layer were varied. As results, the maximum and the excess slurry pressure in sandy ground were linearly proportional to the cover depth. Larger slurry pressure could be applied to increase the stability of the tunnel face when the impermeable layer was located in the ground above the crown in front of the tunnel face. The most effective length of the impermeable grouting layer was 1.0 ~ 1.5D, and the location was 1.0D above the crown level. The safety factor could be suggested as the ratio of the maximum slurry pressure to the active earth pressure at the tunnel face. It could also be suggested that the slurry pressure in the magnitude of 3.5 ~4.0 times larger than the active earth pressure at the initial tunnel face could be applied if the impermeable layer was constructed at the optimal location.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.1199-1213
• /
• 2011

Slurry type shield would be very effective for the tunnelling in a sandy ground, but low slurry pressure could cause a tunnel face failure or a ground settlement in front of the tunnel face. Thus, the stability of tunnel face could be maintained by applying an excess slurry pressure that is larger than the active earth pressure. However, the slurry pressure should increase properly because an excessively high slurry pressure could cause the slurry flow out or the passive failure of the frontal ground. It is possible to apply the high slurry pressure without passive failure if a horizontal impermeable layer is located in the ground in front of the tunnel face, but its location, size, and effects are not clearly known yet. In this research, two-dimensional model tests were carried out in order to find out the effect of a horizontal impermeable layer for the slurry shield tunnelling in a saturated sandy ground. As results, larger slurry pressure could be applied to increase the stability of the tunnel face when the impermeable layer was located in the ground above the crown in front of the tunnel face. The most effective length of the impermeable grouting layer was 1.0~1.5D, and the location was 1.0D above the crown level. The safety factor could be suggested as the ratio of the maximum slurry pressure to the active earth pressure at the tunnel face. It could also be suggested that the slurry pressure in the magnitude of 3.5~4.0 times larger than the active earth pressure at the initial tunnel face could be applied if the impermeable layer was constructed at the optimal location.

• Korean Journal of Comparative Education
• /
• v.28 no.4
• /
• pp.23-49
• /
• 2018

This study aims to consider the subject completion system based on high school credit system in State of California. To achieve research aims, this study analyzed a characteristics of curriculum of credit system in US, subject completion system based on high school credit system in State of California. Based on analysis results, this study search implications for implementing high school credit system in korea. For stable implement of High School Credit System, This study proposed that 'review of relevance of graduation requirement credit', 'effort in Metropolitan and Provincial office of education and School for establishing meaningful subject', 'taking follow-up action in accordance with setting of subject completion standard', 'qualitative improvement of student's subject selection', 'revitalization of career coaching for meaningful subject selection', 'setting of level on connectivity between high school curriculum and university entrance examination', 'a study on the in-depth follow-up about high school curriculum based credit system in foreign country'.

• Economic and Environmental Geology
• /
• v.49 no.1
• /
• pp.63-75
• /
• 2016

The ratio of fractured reservoir is very high in oil & gas fields around the world. The demand of drilling technology for fractured reservoir is expected to increase continuously if oil and gas prices are economical. The purpose of the review study is to help operator or driller in selecting of proper drilling technology for preventing a lost circulation in the fractured formation. In order to achieve this goal, fractured reservoir(formation) they are classified into partial lost circulation formation and total lost circulation formation. In case of partial lost circulation formation, the drilling problem can be solved by using LCM(lost circulation material) mud additive and squeezing cement. For shallow depth, total lost circulation formation can be drilled safely and economically with casing drilling method. Also, for deeper depth, problems of total lost circulation in formation can be solved by applying mud cap, which is one of the drilling methods. This was confirmed through field application such as Italy's Medusa-1 field and Qatar's North field.