발산형 바닥 경사 생성항(DFB, Divergence Form for Bed slope source term)을 엄밀하게 유도하였으며, DFB 중에서 격자의 변에서 평균 수 심을 이용하는 mDFB의 오차를 명백하게 입증하였다. 또한, DFB 기법은 바닥 경사 생성항에 대해 정확한 방법임을 밝혔다. 완전히 잠기기 않은 격 자에 대한 기존의 체적-수심 관계의 오류를 수정하였으며, C-특성의 충족을 위해 완전히 잠기지 않은 변에 대한 처리가 필요함을 검토하였다. 이 연 구를 통해 근사 Riemann 해법으로 천수방정식을 해석할 때 보다 정확한 수단을 제공할 수 있을 것으로 기대한다.

According to the KCI 2012, it is presented that steel fiber can replace minimum shear reinforcement when beams are designed. However, there is no standard for columns, and there is a lack of research on SFRC columns. Therefore, it is evaluated how much the capacity of columns increases according to the volume fraction of steel fiber through the cyclic lateral loading tests. Also, it is evaluated whether steel fiber can replace transverse reinforcements in concrete columns.

As the amount of slag generated annually increases, attempts to recycle slag as high value products are underway in order to develop an efficient resource recycling industry based on slag and derive economic benefits as well. However, the application of electric arc furnace (EOS) slag as construction material is practically limited because of the unstable substances included in it, such as free CaO.(EOS contains a small amount of free CaO, but several limitations still exist. Slag is stored for more than 3 months depending on the quantity of slag, which leads to additional economic loss. In this study, the amount of free CaO present in EOS is quantitatively evaluated to examine its qualities as a potential construction material and verify its application as concrete material. The quantitative analysis of free CaO present in EOS is performed using ethylene glycol. The free CaO contents of EOS samples were found to be below 0.5%. This satisfies the criteria specified in KS F 4571, which states that the CaO content should be below 40% and CaO/SiO2 ratio should be below 2.0. In addition, it was confirmed that free CaO content difference appears to be dependent on the aging period and storage position.

본 연구는 한국과 싱가포르, 인도, 미국의 자유무역협정(FTA) 발효로 인한 양자간 교역증진효과를 통계적으로 비교 분석하고자 한다. 다수의 선행연구에서 양자간 교역 증대효과 추정시 활용된 중력모형(Gravity)을 기본 방법론으로 패널분석(Panel analysis)을 통해 한 국과 FTA 발효국(싱가포르, 인도, 미국)을 효과집단으로, 미발효국은 통제집단으로 구분하여 총 20년의 기간을 설정하여 FTA 발효의 순수효 과를 추정하였다. 자유무역협정의 교역증대효과 분석을 위해 우리나라와 FTA가 발효된 3개 국가(효과집단)와 2015년 기준 우리나라 벌크물 동량 교역 상위 90%의 비중을 차지하는 27개 국가(통제집단)의 횡단면 및 시계열로 구성된 패널자료를 사용하였다. 분석 결과 FTA 발효는 우리나라 벌크물동량 증대에 기여한 것으로 나타났다. 특히 본 연구의 대상국가인 싱가포르, 인도, 미국과는 자유무역협정 발효로 인한 무역 창출효과가 발생하였고 ASEAN 및 NAFTA+3의 경우 무역전환효과가 발생하였다. 한편 자유무역협정 이외의 GDP, 1인당 GDP 변수는 벌크 물동량과 정(正)의 효과를 보이는 것으로 나타났으며, 거리 변수는 물동량과 부(負)의 효과를 보이는 것으로 분석되었다. 마지막으로 국가별 패널자료 분석 결과 하우스만 검정 및 LR검정을 시행하였으며, 고정효과모형이 임의효과모형보다 적합한 것으로 나타났다.

국제 교역에 있어서 항만은 중심 거점기능을 수행하지만 FTA가 해상물동량과 항만물동량에 미치는 영향을 실증적으로 분석한 연 구는 드물다. 해운항만 분야의 경우 물동량은 항만시설 확충, 항만처리능력 산정 및 선박확충, 항로추가로 인한 선대구성의 중요한 자료임에도 불구하고 선행연구에서 실증분석이 대부분 교역금액 기준으로 이루어져 왔다. 향후 체결될 FTA의 경제적 기대효과 분석도 중요하지만, 현재 체결된 FTA의 효과를 파악하는 것도 실증적으로 의미가 크다. 따라서 본 연구에서는 2010년 체결된 한-인도 FTA를 대상으로 하여 FTA가 한국 물동량에 미치는 영향을 FTA의 경제적 파급효과를 파악하는데 네트워크 모형을 적용하여 실증 분석하였다.

Based on the study of researchers carried about SFRC, it was found that SFRC was effective to achieve flexural toughness according to higher volume fraction. On the other hand, higher volume fraction did not effect at compressive strength and toughness.

This paper is the first of its kind using a non-linear approach based on cross-correlation function (CCF) to investigate the information arrival hypothesis in crude palm oil (CPO) futures market. Based on daily data from 1986 to 2010, our empirical results reveal that: First, the volume of volatility is not a proxy of information flow. Second, dependence causality running from current return to future volume in conditional variance exhibit an asymmetric pattern of time span with different signs of correlation between price and volume series. This finding indicates the presence of noise traders’ hypothesis of price-volume interaction in CPO futures market. Both findings suggest that this futures market is weak-form inefficiency. In terms of investors’ behavior, they tend to change their expectations on current return based on errors made in previous trade in generating abnormal volume in the subsequent period. As implied, it is advisable for the investors devise their future trading strategies according to time span and changes of return.

This study empirically evaluates the impact of exchange rate volatility, foreign direct investment, terms of trade, inflation, and industrial production and foreign exchange reserves on Pakistani trade volume over the period of 1975-2010 using quarterly data set. The study employs financial econometrics methods such as Augmented Dickey Fuller (ADF) test GARCH (1, 1) technique and Almon Polynomial Distributed Lag (APDL) models to estimate the relationship of variables. Findings of the study are in accordance with theoretical relationships presented by Clark, Tamirisa, Wei, Sadikov, & Zeng (2004), McKenzie (1999), Dellas & Zilberfarb (1993) and Côté (1994). These findings are also in accordance with the empirical studies which support positive relationship of exchange rate volatility and exports presented by Hsu & Chiang (2011), Chit (2008), Feenstra & Kendall (1991), Esquivel & Larraín (2002) and Onafowora & Owoye (2008). Findings of the study in terms of imports are supported by the studies such as Lee (1999), Alam & Ahmad (2011) and Arize (1998). The study also recommends some very important policy prescriptions.

This study was evaluated the field applicability of high fluidity concrete for pc sleeper using high volume fly ash.

This paper investigated the thermal and mechanical properties of high-volume fly ash concrete for potential application in mass concrete.

Concrete behaves as a brittle material with low tensile strain capacity. By adding fibers, the cracking in concrete matrix is controlled, and the mechanical properties are improved. In this study, the mechanical properties of fiber reinforced concrete are compared with fiber type and fiber volume fraction. From the results, the fiber mixed in concrete must be at least 0.5% regardless fiber type, in order to ensure the compressive and flexural strength equivalent or higher than OPC.

This paper presents an experimental study on the improvement of ductile and flexural strength for high performance fiber reinforced cementitous composites (HPFRCC). The test was evaluated by compressive and flexural behavior of HPFRCC(compressive strength : 180 MPa) according to aspect ratio and volume contents of steel fiber. The flexural strength was increased by aspect ratio near 100 or increasing volume contents of steel fiber while there is no clearly result on the compressive strength.

Concrete behaves as a brittle material with low tensile strain capacity. By adding fibers, the cracking in concrete matrix is controlled, and the durability is improved. In this study, the microstructure and Chloride diffusion resistance of fiber reinforced concrete are compared with fiber type and fiber volume fraction. From the results, the fiber mixed in concrete must be at least 0.5% regardless fiber type, in order to ensure the chloride diffusion coefficient higher than OPC at 91days. However, the micro structure distribution is affected with fiber volume fraction and fiber type at range 10~100nm.

Domestic sewerage treatment plant is operated by activated sludge method and its modified method by using microorganism. In most cases, a method of using microorganism is directly controlled by the operator based on individual judgment through factors of DO, pH and ORP. In addition, under aerobic condition in bioreactor, energy consumption including excessive air injection is learned to be somewhat plenty. In order to solve this problem, in most of the process, improvement of internal recycling and activated environmental factor of microorganism were researched extensively. However, as factors are changed depending on various conditions, it is not sufficient as an indicator of judgment. As such, a research on operation of bioreactor that measures metabolic change in short time by directly measuring activated condition of microorganism using NADH fluorometer is required in reality.It is considered that the method like this could supplement problem of energy consumption being occurred in the existing treatment method and operational optimization of bioreactor would be enabled by controlling optimal air volume. Therefore, in this study, in order to obtain optimal operational indicator of bioreactor, proper air volume control test was performed and through batch test and site evaluation, possibility of NADH sensor being utilized as operational control indicator of bioreactor is intended to be analyzed. In order to compare with measured value, DO, ORP that are operational control indicator of existing bioreactor were used. As MLSS concentration was increased through batch test, NADH value was increased and site evaluation also showed similar tendency to batch test. Resultantly, it could be confirmed that changing level of NADH fluorometer was a sensor that could measure bioreactor condition effectively and optimized scale of bioreactor is considered to be utilized.

Concrete shrinkage is happened due to the cement hydration and water evaporation from early ages, and it induces crack of concrete. In this study, the crack resistance of fiber reinforced concrete was compared with fiber type and fiber volume fraction. From the results, cracking is delayed when the volume fraction is increased. And, crack resistance is improved regardless of fiber type.

The hoop bars confining the longitudinal reinforcement increase the strength and ductility of the column. The enhancement effects on the strength and ductility of the RC columns with rectangular cross section are represented differently depending on the degree of hoop bars reinforcement. A theoretical studies were performed using the previous equations proposed by earlier researchers. As the results of this theoretical studies, the yield strength bar and the vertical space of hoop bars are the most influenced in the strength and ductility of the columns. A square RC column than a rectangular RC column was found to receive a larger impact on the strength and ductility effect.

From the previous research, as a solution of carbonation of high-volume SCM concrete, outstanding performance of emulsified refined cooking oil with applying on the surface of the concrete was suggested. As a comparative study, the aim of this research is evaluating carbonation resistance and pore structure of high-volume SCM concrete depending on the painting substances of emulsified refined cooking oil and modified silicate base permeating paint, which is commercial product by mock-up test.

Traffic accidents on the expressways during the high speed driving are severe and more damaging, compared with other traffic accidents. There has been much effort to reduce the traffic accidents by seeking for the cause of the accidents. Apart from drunk driving and driving while drowsy caused by personal carelessness, one of the main causes of the accidents on the expressways is the limit to the straight-ahead. The straight-ahead is much affected by climate and topography. Existing research on this subject investigates the accidents during the driving on the expressways under bad weather, the accidents on the freeways with design problems regarding the topology and grade and the accident frequency varying with traffic volume. The current study suggests a model including precipitation and traffic volume at a time and aims at examining their impacts on the traffic accidents on the expressways by using a binomial logistic regression analysis. The data used were the traffic accident frequency per day over a year on each link of two expressways, Donghae and Yeongdong, which represent Yeongdong and Yeongseo regions of Gangwon Province. The results tell that precipitation and traffic volume significantly affect the occurrence of the traffic accidents. The accident occurrence is also significantly different between the two expressways and even more significantly different between links within each expressway. Further research topics were identified, including the distinction between rainfall and snowfall, the inclusion of mediating variables such as the limit to the straight-ahead due to the precipitation and the differentiation between the degrees of fatality of the traffic accidents.

항만은 우리나라와 같이 국가경제에서 수출입 의존도가 높은 국가에서는 중요기간시설이자 많은 부가가치를 창출하는 매우 중요 한 역할을 맡고 있다. 중요한 시설임에도 불구하고 과거에는 항만에 대한 인식이 미흡했었으나 2000년대에 들어 세계 컨테이너 물동량이 증 가하고 중국의 경제가 발전함에 따라 동북아 지역에 물동량이 많이 발생하게 되어 항만의 역할의 중요성과 인식도 변화하였다. 본 연구는 우 리나라 항만 기본계획 및 항만 구분에 따른 항만 역할을 검토하여 항만 물동량에 영향을 미치는 결정요인을 연구하고자 한다. 연구의 대상으 로는 부산항과 광양항 같이 글로벌 환적항만을 제외한 배후지역 물동량의 영향을 많이 받는 국내 중소형 컨테이너항만을 대상으로 정하였다. 분석결과 항만물동량에 영향을 미치는 요인으로는 접안능력, 활성화정도, 연결국가수, GRDP, 제조업체수로 나타났다.