PURPOSES : The purpose of this study is to verify the influences on the compactibility evaluation of WMA (Warm Mix Asphalt) mixture by laboratory experiments. METHODS : Two types of WMA additives (chemical and wax types) and two types of compactors (marshall and gyratory) are used in laboratory experiments. In addition, two types of WMA processes (wet and dry) are tested to verify the impact of manufacturing process. RESULTS : The laboratory results show that the effects of compaction method on compactibility are different depending on the type of additive. The compaction method has a significant impact on WMA mixture with chemical type additive to extent that it determines whether required criterion is satisfied, but only little on WMA mixture with wax type additive. In the case of wet process for WMA mixture manufacturing, it is hard to assess the air void of HMA mixture made of same asphalt binder used in WMA mixture since the additive has already been added in asphalt binder. And the test results show that air voids of HMA mixture vary within properties of asphalt binder. CONCLUSIONS : Through this study, it is found that compactibility of WMA mixture is affected by the compaction methods depending on the additive types and by the WMA mixture manufacturing process. Therefore, those are recommended to be considered when evaluating compactibility of WMA mixtures.

본 연구는 식물검역 분야에서 주요하게 사용되고 있는 메틸브로마이드 훈증제로 인해 발생하는 약해를 저감하기 위한 물질을 모델식물인 애기장대를 이용하여 스크리닝하였다. 사전연구를 통하여 메틸브로마이드 훈증제의 식물 독성 메커니즘으로 활성산소발생와 식물 성장 호르몬인 옥신의 식물체 내 분배억제효과가 발생하는 것을 바탕으로 하여, 약해 저감물질후보군으로 활성산소를 제거하는 역할을 하는 ROS scavenger 2종 (NAC, GSH)과 옥신을 훈증제 처리 전 애기장대에 처리한 후 약해의 저감 정도를 육안평가와 더불어 관련 유전자의 발현을 확인하였다. 연구 결과 메틸브로마이드에 의해 유도된 약해는 옥신보다는 활성산소를 저감시키는 물질후보군들에서 약해 저감효과가 나타났다. 이 중 GSH을 이용하여 농도구배하여 전처리하였을 때, 5 mM GSH 전처리 후 메틸브로마이드 훈증 시 약해 저감효과가 두드러졌다. GSH 전처리 시 식물체 내에 MBF1c와 HSP70 유전자 발현이 증가하는 것을 확인하였으며, 이는 메틸브로마이드 훈증으로 유도되는 약해를 방어하는 역할을 담당하였을 것이라고 평가된다. 따라서, 식물검역 훈증제 메틸브로마이드에 의해 발생하는 약해를 저감하는 데 GSH의 사용가능성을 평가하였으며, 이를 기반으로 다양한 식물체에 적용하여 수출입 시 약해로 인한 경제적 손실을 감소시킬 수 있기를 기대한다.

To meet rapidly changing market demands, manufacturers strive to increase both of productivity and diversity at the same time. As a part of those effort, they are applying flexible manufacturing systems that produce multiple types and/or options of products at a single production line. This paper studies such flexible manufacturing system with multiple types of products, multiple Bernoulli reliability machines and dedicated buffers between them for each of product types. As one of the prevalent control policies, priority based policy is applied at each machines to select the product to be processed. To analyze such system and its performance measures exactly, Markov chain models are applied. Because it is too complex to define all relative transient and its probabilities for each state, an algorithm to update transient state probability are introduced. Based on the steady state probability, some performance measures such as production rate, WIP-based measures, blocking probability and starvation probability are derived. Some system properties are also addressed. There is a property of non-conservation of flow, which means the product ratio at the input flow is not conserved at the succeeding flows. In addition, it is also found that increased buffer capacity does not guarantee improved production rate in this system.

PURPOSES : The use of hydrated lime or other liquid anti-stripping agents (ASA) is the most common method of improving the moisture susceptibility of asphalt mixes. ASAs are also known to have an anti-aging effect, according to several researchers. Therefore, the use of ASAs is expected to enhance the stability of asphalt pavements. The purpose of this study is to investigate the anti-aging effect of ASAs that are found in the domestic market. METHODS : In this study, an asphalt binder and a mixture mixed with typical domestic solid and liquid ASAs were prepared and aged to evaluate the physicochemical changes. A liquid additive developed by a Korean oil refinery was used as the liquid ASA, and hydrated lime was utilized as the solid ASA. The aging process of the asphalt was determined in the laboratroy based on previous studies to simulate the aging process inh te field. RESULTS : The result of the laboratory experiment indicates that both the solid and liquid ASAs have an anti-aging effect. Moreover, the liquid additive performed relatively better than the hydrated lime. CONCLUSIONS : If ASAs have an anti-aging effect in addition to the anti-stripping function, it is expected to improve the stability of the asphalt pavement significantly. However, few studies have been carried out on the anti-aging effect of ASAs found in the domestic market. In this study, we conducted a fundamental study on the anti-aging effect to help in the selection and use of ASAs in the domestic asphalt-paving industry.

In this paper, we present a new way to derive the mean cycle time of the G/G/m failure prone queue when the loading of the system approaches to zero. The loading is the relative ratio of the arrival rate to the service rate multiplied by the number of servers. The system with low loading means the busy fraction of the system is low. The queueing system with low loading can be found in the semiconductor manufacturing process. Cluster tools in semiconductor manufacturing need a setup whenever the types of two successive lots are different. To setup a cluster tool, all wafers of preceding lot should be removed. Then, the waiting time of the next lot is zero excluding the setup time. This kind of situation can be regarded as the system with low loading. By employing absorbing Markov chain model and renewal theory, we propose a new way to derive the exact mean cycle time. In addition, using the proposed method, we present the cycle times of other types of queueing systems. For a queueing model with phase type service time distribution, we can obtain a two dimensional Markov chain model, which leads us to calculate the exact cycle time. The results also can be applied to a queueing model with batch arrivals. Our results can be employed to test the accuracy of existing or newly developed approximation methods. Furthermore, we provide intuitive interpretations to the results regarding the expected waiting time. The intuitive interpretations can be used to understand logically the characteristics of systems with low loading.

본 연구는 한국과 인도 상장기업 1,191개를 대상으로 2002년부터 2010년까지의 자료를 사용하여 양국 기업의 자본구조 및 부채만기 결정요인에 관한 연구를 수행하였다. 자본구조를 결정하는 기업 특성요인들에 대한 분석결과는 첫째, 이익과 기업규모는 양국 간에 일치함을 보이는데, 총자산영업이익율은 부채비율과 부(-)의 관계와 자본조달순서이론(pecking order theory)에 부합함을 보인반면, 기업규모는 정(+)의 관계와 상충이론(trade-off theory) 및 대리인이론(agency theory)에 부합함을 보인다. 둘째, 유형자산과 성장기회는 양국 간에 불일치함을 보이는데, 유형자산비율은 한국기업의 경우 부(-)의 관계와 자본조달순서이론에 부합함을, 인도기업의 경우 정(+)의 관계와 상충이론 및 대리인이론에 부합함을 보이고, 시장가 대 장부가 비율은 시장가 부채비율에 대해서 양국 모두 부(-)의 관계와 상충이론, 대리인이론 및 자본조달순서이론에 부합함을 보인다. 부채만기를 결정하는 기업 특성요인들에 대한 분석결과는 첫째, 유형자산, 이익 및 기업규모는 한국기업의 경우 예상대로 부(-)의 부호를 보여 이들 변수가 커질수록 부채만기가 길어짐을 보이나, 인도기업의 경우에는 유의한 관계를 보이지 않는다. 둘째, 성장기회는 한국기업의 경우 예상과 달리 정(+)의 관계를 보이는 반면, 인도기업의 경우는 예상대로 부(-)의 관계를 보이는 것으로 나타났다. 한편, 인도 재벌기업이 한국 재벌기업보다 부채비율이 유의하게 높은 것으로 나타나고 있는데, 이는 한국재벌 대주주 지분율이 인도재벌에 비해 낮을 뿐만 아니라 재벌에 대한 감시비용이 더 높기 때문에 한국 재벌의 경우 부채의 대리인비용이 인도 재벌보다 크기 때문인 것으로 생각된다. 이와 같이 양국 기업의 자본구조와 부채만기가 다른 이유는 첫째, 인도는 영국의 영향을 받아 영미법(common law) 에 기반을 두고 있고 법적으로는 투자자 보호가 잘 되어 있으나 실질적으로는 정부와 사법부의 부패와 비효율적인 법 시스템으로 인해 자본시장을 통한 자금조달이 미미하고, 둘째 인도의 은행예금/GDP 비중과 대출/예금 비중이 우리나라에 비해 매우 낮을 뿐만 아니라 국영은행 위주의 중장기성 정책자금 대출이 많이 이루어지고 있는 관계로 은행을 통한 자금조달에도 한계가 있고, 셋째 인도는 기업간 신용(trade credit)이나 관계회사 대출과 같은 대체자금(alternative financing)에 대한 의존도가 매우 높고, 넷째 인도의 법인세와 이자 및 배당소득세 제도가 레버리지로 인한 세금효과를 더 크게 만들기 때문인 것으로 보인다.

Disaster management is successful if the situation in the event of an accident to minimize casualties and property damage, and commitment to improve the efficiency of personnel and material, and further the administration site conditions promptly reported to the director or the people. transmit from one generation to the next the stability of the society could seek would be. In this respect.

Pesticide residues were investigated in 16 commodities (rice, foxtail millet, buckwheat, kidney bean, peanut, sesame, orange, grapefruit, kiwifruit, spinach, perilla leaves, leek, garlic stem, garlic, ginger and oak mushroom)collected from 22 provinces (Seoul, Busan, Incheon, Daegu, Daejeon, Gwangju, Ulsan, Suwon, Seongnam, Goyang,Bucheon, Yongin, Cheongju, Jeonju, Jeju, Cheonan, Changwon, Pohang, Gumi, Jinju, Wonju and Yeosu) in 2009. Pesticides (172 kinds) were analyzed using multiresidue method by GC/MS/MS from 510 samples, and phenthoate in kiwifruit was violated by exceeding MRL. The intake assessment for 24 kinds of pesticide residues including the detected pesticides at multi pesticide residue monitoring (bifenthrin etc.) were carried out. The result showed that the ratio of EDI (estimated daily intake) to ADI (acceptable daily intake) was 0.000007~0.458% which means that the detected pesticide residues were in a safe range so that residual pesticides in the agricultural products in Korea.

Melanin 생성에 관여하는 tyrosinase 유전자의 발현을 억제하는 물질을 탐색하고자 tyrosinase promoter를 지닌 Bl6 mouse melanoma cell해 앙파 methanol 추출물을 처리한 바 양파 methanol 추풀물은 10.0㎍/ml, 100.0 ㎍/ml, 1.0 ㎎/ml의 농도에서 대조군에 비해서 약 15%, 23% 57%의 억제효과를 나타냈으며 세포생존율은 1.0 ㎍/ml, 10.0 ㎍/ml, I00.0 ㎍/ml, 1.0㎎/ml의 농도에서 약 126 %, 92%. 85%, 64%로서 세포독성이 낮게 나타났다. Ethyl acetate, butyl alcohol, 그리고 물 용매 분획물은 tyrosinase 유전자의 발현물 억제하는 효과가 없었지만 methylene chloride 용해 분획물은 10.0 ㎍/ml과 100.0 ㎍/ml의 농도에서 약 37%와 35%의 발현율을 나타냄으로서 대조군에 비해 크게 억제하였다.