• 한국지하수토양환경학회지:지하수토양환경
• /
• 제18권6호
• /
• pp.48-55
• /
• 2013

This study aimed at characterizing unsaturated zone at the source zone area contaminated by DNAPL and investigating feasibility of soil vapor extraction (SVE). Five boreholes with three multi-level screens at the depth of 3.0~4.5 m, 5.5~7.0 m, and 8.0~12.0 m were installed at the source zone. Pneumatic tests were performed to determine the permeability of porous medium. Permeability was estimated to be 81.6 to 203.7 darcy, depending on the applied solutions, which was contradicted by grain size analysis of cored soil samples leading to 3.51 darcy. This is due to air flow through gravel pack during the early stage of pneumatic test. Pressure-drawdown curve in the late stage also well showed the leaky aquifer type, indicating air leakage to the ground. Air flow tests were also carried out to investigate air flow connectivity between multi-level wells, indicating that the horizontal air flow was well developed between the lower screens of the wells, not between the upper and middle screens due to the leakage to the surface. For the SVE test, there was no noticeable variation in TCE vapor concentration between three different test runs: 1. 8 hours daily for 5 days, 2. 24 hours together with air blowing at another well (BH1), 3. five consecutive days. Even for five-day consecutive test, total amount of removed TCE was estimated only to be as low as 46.5 g.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2007년도 동계학술발표대회 논문집
• /
• pp.105-112
• /
• 2007

Recently developed raised floor heating system is not only capable of basic function to reduce noise between floors, but also is a multi-functional floor heating system enabling natural ventilation. The procedure of this system for natural ventilation is to import outdoor air through bottom space of the floor heating system, circulate indoor space and discharge it out of ceiling. In winter, powerless natural ventilation is possible with buoyancy effect caused by temperature difference between outdoor and indoor. And it also allows saving of energy by importing pre-heated air in bottom space of the floor heating system. To evaluate ventilation performance of this system, on-site measurement was conducted in 2 test laboratories, and the nominal air change rate was satisfied as 0.4$\sim$0.8 h-1 under the condition of outdoor temperature $5^{\circ}C{\sim}-5^{\circ}C$, which was evaluated as highly possible to be applied as a natural ventilation system in multi-family houses.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2007년도 정기 학술대회 논문집
• /
• pp.713-718
• /
• 2007

Structural tests often involve a large amount of complicated information. Data models can be used to efficiently organize the information. This paper briefly describes a data model for structural tests including hybrid tests, performed by the Real-Time Multi-Directional (RTMD) facility at the ATLSS Center of Lehigh University in America. The RTMD facility is an equipment site within the George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES). The data model is called the Lehigh Model. An overview of classes and attributes of the Lehigh Model is presented, and the Lehigh Model is compared with other data models to show its benefits for structural testing.

• 마케팅과학연구
• /
• 제20권2호
• /
• pp.123-134
• /
• 2010

考虑到消费者和供应商的利益, 公司利用网络为媒介来沟通并向消费者销售产品. 这一趋势使得很多研究者和实践者都关注网上购物环境这一领域. 本文测试了网上消费者行为和具有不同快乐主义水平的网址的模型. 与以往的研究不同, 我们包括了所有三种情绪(激励, 快乐和支配)并将此运用到模型中. 本研究中, 我们假设网址的外观, 例如背景颜色, 音乐和字体在消费者最初接触到网址时均影响三种情绪(Mazaheri, Richard, and Laroche, 2011). 反之, 这些情绪会影响消费者对网址氛围的感知–网址信息量, 效率和娱乐性的感知. 这些假设与Zajonc (1980)的研究一致. 他认为情感的作用是独立于感性的和认知操作并且可以影响回应. 我们因此提出网址氛围和流量的感知影响消费者对网址和产品的态度, 网址卷入和购买意图. 另外, 我们研究网址的快乐主义水平对模型中所有关系的调节作用. 因此, 我们比较享乐网址路径系数 "高" 和 "低". 我们用39个真实的网站涵盖了12种产品类别(8种服务和4种实物产品)来测试模型. 这其中, 回复者认为20个是高享乐, 19个为低享乐. EQS6.1的结果支持整体模型: x2=1787 (df=504), CFI=.994; RMSEA=.031. 所有假设都是显著的. 另外, 多群组分析表明在高享乐和低享乐网址群组之间的几个非不变量结构路径. 这些结果支持三种情绪影响消费者对网址氛围, 流量和其他消费者行为变量的认知. 我们发现快乐极大的影响这网址态度和网址娱乐性的认知. 激励积极的影响其他两种情绪, 网址信息量的认知和网址卷入. 而且, 激励对流量的影响非常显著. 这些结果说明在支配和消费者对网址效率的认知之间有很强的相关. 支配同时和网址态度和流量相关. 另外, 结果还表明网址卷入和对产品的态度是购买意图最重要的两个因素. 网址信息量和流量也积极的影响购买意图. 多群组分析的结果支持网址快乐主义的调节作用. 与低(高)享乐网址相比, 实用(享乐)属性对其他变量的影响比高(低)享乐网址更强. 在这三种情绪中, 支配(控制感)影响在高享乐网址中更强. 快乐影响在低享乐网址中更强. 而且, 网址信息量的影响对高享乐网址更强. 另一方面, 信息效率对网址信息量认知的影响和网址卷入对产品态度的影响在低享乐网址中更强.

• 한국해안·해양공학회논문집
• /
• 제24권4호
• /
• pp.247-256
• /
• 2012

본 연구는 다층지반으로 구성된 방조제의 침투변화에 따른 안정성을 검토하기 위하여 현장조사와 역해석 방법으로 투수계수와 침투수량을 결정하고, 제체의 변형량과 유실량 측정을 위하여 침투모형시험을 수행하여 가장 합리적인 수치해석 방법을 결정하였다. 검토결과 방조제는 다층지반구조물로 투수계수 차이에 의해 바닥보호공과 성토체 경계부에서 유실이 발생하고 이로 인해 방조제의 변형이 발생한다는 것을 예측할 수 있었다. 한편 침투모형 시험에 대한 수치해석결과 한계유속에 의한 방법은 실측치가 해석값보다 작게 나왔으나 그 경향이 유사하여 실제 단면에 적용 가능할 것으로 판단되었다.

• 한국생산제조학회지
• /
• 제22권3호
• /
• pp.372-379
• /
• 2013

In this study, we investigated the traits of the clad metals used in hot-rolled clad steel plates. We examined the sensitization and mechanical properties of STS 316 steel plate and carbon steel (A516) under the specific circumstances of post heat treatment and whether a weld was multilayered and thick or repeated because of repairs. The test conditions were as follows. The clad steel plates were butt-welded using FCAW/SAW, and the heat treatment was conducted at $625^{\circ}C$, for 80, 160, 320, 640, or 1280 min. The change in the corrosion resistance was evaluated in these specimens. In the case of the carbon steel (A516), as the heat treatment time increased, the annealing effect caused the tensile strength to decrease. The micro- hardness gradually increased and then decreased after 640 min. The elongation and contraction of the area increased gradually. An oxalic acid etch test and EPR test on STS316, a clad metal, showed a STEP structure and no sensitization. From the test results for the multi-layered and repair welds, it could be concluded that there is no effect on the corrosion resistance of clad metals. In summary, the purpose of this study was to suggest some considerations when developing on-site techniques and evaluate the sensitization of stainless steels.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2006년도 추계 학술발표회
• /
• pp.574-584
• /
• 2006

Bi-directional loading test data are available to evaluate the design parameters which reflect the characteristics of a construction method and the variations of ground at the site where drilled shafts are installed. The method to obtain the design parameters of a real bridge by hi-directional loading test was introduced. The plans of multi-level testing and installation of measuring instruments should be made according to the rough estimation of axial bearing capacity, the length of pile, and the construction method. While the relationship between end bearing resistance and displacement was obtained directly from the hi-directional loading test, the relationship between unit side resistance and displacement was calculated through the measuring values. 1% displacement of pile diameter was adopted as the criteria of failure for ultimate resistance. As the settlement of pile head at the total ultimate bearing capacity obtained from these method was less than 1.5 % of pile diameter, this method was conservative to use in the field.

• 한국결정성장학회지
• /
• 제20권6호
• /
• pp.278-282
• /
• 2010

Tm 도핑에 따른 $BaTiO_3$ ceramics의 전기적 특성과 열화 거동에 미치는 영향에 대하여 core-shell 형성과 가속열화시험에 의한 미세화학변화의 관점에서 연구하였다. $Tm_2O_3$를 첨가하지 않은 $BaTiO_3$와 1 mol%를 첨가한 $BaTiO_3$를 펠렛과 적층 형태의 시편으로 각각 제조하였다. 1 mol% $Tm_2O_3$가 첨가된 유전체 시편의 유전상수는 $Tm_2O_3$를 첨가하지 않은 시편에 비해 약 40% 높게 나타났고 X7R 조건을 만족하였다. 절연저항 또한 1 mol% $Tm_2O_3$가 첨가된 시편은 $5.43{\times}10^{10}{\Omega}$으로 $Tm_2O_3$를 첨가하지 않은 시편의 $1.11{\times}10^{10}{\Omega}$보다 높게 나타났다. 이는 $Tm^{3+}$ 이온이 Ba site와 Ti site에 선택적으로 치환되고 유전체 미세조직 내에 core-shell 구조를 형성하여 전기적 특성을 향상시킨 것으로 설명된다. 각각의 조성에 따라 제조된 적층 시편의 $150^{\circ}C$, 70 V, 24시간 가속열화시험결과에 따르면, 1 mol% $Tm_2O_3$가 첨가된 $BaTiO_3$는 첨가되지 않은 시편에 비해 전극 층으로의 산소확산이 감소됨을 확인하였고, 이는 $Tm^{3+}$ 이온의 Ti site 치환에 의해 발생한 산소공공이 Ni 전극과 반응할 수 있는 과잉 산소를 줄여주기 때문으로 판단된다.

• 대한원격탐사학회지
• /
• 제35권3호
• /
• pp.471-482
• /
• 2019

달 탐사용 고해상도 스테레오 카메라의 임무는 달 궤도선 및 착륙 선에 탑재되어 달 표면의 3차원 지형정보를 제공하는데 있다. 이를 통해, 달 착륙 후보지를 탐색하고 착륙 시에는 달 표면 근접에 따른 근거리 입체영상을 실시간으로 제공하여 정확한 지점에 착륙이 가능하도록 한다. 본 논문에서는 달 탐사선에 탑재되는 달 탐사용 고해상도 카메라 개발을 위한 지상모델인 다기능 스테레오 카메라를 활용하여 고해상도 스테레오 카메라에 요구되는 임무를 검증하고 결과를 분석하기 위해 지상검증 및 분석 시스템을 제안하였다. 지상검증 및 분석 시스템은 임무 검증을 위한 임무검증항목과 시험계획을 제공하며, 시험 수행 후 결과를 분석하게 된다. 이를 위해 본 논문에서는 달 지형과 유사한 지역을 대상으로 지상 임무항목시험 계획을 세우고, 항공촬영을 통해 스테레오 영상을 획득하였다. 분석장치를 통해 스테레오 영상으로부터 영상을 보정 및 매칭 후 수치표고모델(DEM)을 추출하고 3차원 영상을 생성하여 결과를 분석하였다. 달 탐사용 고해상도 카메라에 요구되는 임무수행항목이 검증되었고, 스테레오 영상을 처리할 수 있는 지상처리분석 시스템이 확보 되었다.

• International Journal of Contents
• /
• 제13권4호
• /
• pp.23-28
• /
• 2017

Of the total economic loss caused by disasters, 40% are due to floods and floods have a severe impact on human health and life. So, it is important to monitor the water level of a river and to issue a flood warning during unfavorable circumstances. In this paper, we propose a modified error function to improve a hydrological modeling using a multi-layer perceptron (MLP) neural network. When MLP's are trained to minimize the conventional mean-squared error function, the prediction performance is poor because MLP's are highly tunned to training data. Our goal is achieved by preventing overspecialization to training data, which is the main reason for performance degradation for rare or test data. Based on the modified error function, an MLP is trained to predict the water level with rainfall data at upper reaches. Through simulations to predict the water level of Nakdong River near a UNESCO World Heritage Site "Hahoe Village," we verified that the prediction performance of MLP with the modified error function is superior to that with the conventional mean-squared error function, especially maximum error of 40.85cm vs. 55.51cm.