• The Korean Journal of Financial Management
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• v.14 no.2
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• pp.253-271
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• 1997

본 연구는 1988년부터 1994년까지 우리나라 주식시장에 상장된 IPO 주식의 장단기 성과를 분석하고, IPO 기업들의 상장 후 영업성과를 상장 이전의 영업성과와 비교하는 데 그 목적이 있다. 본 연구의 특징은 가격제한폭 제도가 상장 후 IPO 주가에 미치는 영향을 고려한 점에 있다고 할 수 있으며, 실증분석 결과 다음과 같은 사실들을 발견하였다. 단기적으로 볼 때, IPO 주식의 비정상 최초수익률은 가격제한폭을 고려하여 측정하는 경우에 훨씬 더 높게 나타나며 또한 상승시장의 경우에 더 높게 나타난다. IPO 주식은 상장 이후에도 추가적인 초과수익을 올리며, 상장 직후에 과잉반응 현상을 동반한다. 장기적으로 볼 때, IPO 주식의 수익률은 시장 평균수익률에 미치지 못한다. IPO 기업들의 영업성과가 상장 이후에 현저히 악화되는 것으로 나타난다. 이는 IPO 기업들이 공개모집을 하는 과정에서 기업내용을 과대포장(window-dressing)하는 증거라고 볼 수 있다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.124-125
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• 2019

The use of road cutters in the maintenance of obsolete underground facilities maintains polluting dust, cutting sludge, etc, polluting the air environment, soil, and water, causing civil complaints caused by noise, and consequently interrupting work. Therefore, it is time for eco-friendly pavement cutting technology for fugitive dust and cutting sludge emission management and noise management. This study was based on research by the development of eco-friendly pavement cutting technology in urban areas. In this study, the current state of existing road cutters is investigated and the patented technology analysis of road cutters is conducted to derive the design elements of eco-friendly pavement cutting technology.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.211-218
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• 2010

Volume of concrete slab changes by temperature and moisture effects. At that time, tensile stress develops because the slab volume change is restrained by friction resistance between the slab and subbase, and then crack occurs occasionally. Accordingly, researchers have made efforts to figure out the friction characteristics between the slab and subbase by performing push-off tests. Lately, researches to analyze concrete pavement behavior by the friction characteristics have been performed by finite element method. In this study, The friction characteristics between the slab and subbase were investigated based on the friction test results for lean concrete, aggregate, and asphalt subase widely used in Korean concrete pavements. The energy method bilinearizing relation between nonlinear friction resistance and displacement were suggested. The friction test was modeled by 3-D finite element program, ABAQUS, and the model was verified by comparing the analyzed results to the test results. The bilinear model developed by the energy method was validated by comparing analysis results obtained by using the nonlinear and bilinear friction resistance displacement relation as input data. A typical Korean concrete pavement was modeled by ABAQUS and EverFE and analyzed results were compared to evaluate applicability of the bilinear model.

• Research in Plant Disease
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• v.17 no.1
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• pp.1-12
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• 2011

Incidence of Phytophthora blight of hot pepper (Capsicum annuum) and yield (fresh weight) of pepper fruits were investigated at four separate fields located in Cheongwon, Boeun, Eumsung, and Goesan, which are major pepper production areas in Chungcheongbuk-Do. In all of the experimental fields except the Goesan field, increased incidence of Phytophthora blight led to decreased yield of pepper fruits. The harvest time in which the yield of red pepper fruits was highly correlated with the incidence of Phytophthora blight was different between areas: it was highly correlated in the third harvest in Cheongwon (y=-11.0x+435.2, $r^2$=0.99), but in the second harvest in Boeun (y=-15.0x+944.6, $r^2$=0.76). In contrast, there was a very low correlation between the pepper yield and the disease incidence in Goesan in which pepper seedlings grafted on resistant stocks were planted. The final disease incidence in the Cheongwon experimental field reached 100% more than 40 days later in 2007 compared with that in 2006. The control threshold of Phytophthora blight in the pepper fields where disease incidence had been lower than 5% was set as 0.8% disease incidence, which caused less than 5% yield loss.

• Korean Journal of Food Science and Technology
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• v.4 no.1
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• pp.18-23
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• 1972

Fried instant noodles, manufactured on laboratory scale, preserved in sunlight, room temperature, removed package, at $30{\pm}2^{\circ}C$ and corrugated fiber board box to investigate the oxidative stability of fried products under a few factors of storage for 150 days. And obtained results were as follow. 1) Peroxide value P.O.V. and Acid value A.V. of fried instant noodles were increased slightly during the storage in orange color polycello package in the corrugated fiber board box in the dark room as shown in Fig. 1 and 2. They had not rancid odor and showed P.O.V. 18.8 after 150 days. 2) Preserving in room temperature removed package or with polycello package exposed to sunlight, P.O.V. and A.V. increased rapidly up to 100, 5 and they had rancid odor within 30 days. 3) Peroxide value showed increasing tendency on the storage at $30{\pm}2^{\circ}C$ and scattered light and rancid odor appeared from 90 to 120 days. 4) As peroxide value and refractive index increased, iodine value were decreased as Fig. 3. 5) In these test, P.O.V. is correlated with the organoleptic evaluation of rancidity however, they were not coincided exactly.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.3
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• pp.51-58
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• 2008

Development of a new design guide which is based on empirical-mechanistic concept for pavement design is in action. It is called AASHTO 2002 Design Guide in USA and the KPRP(Korean Pavement Research Project) in Korea. The material characteristic of hot mix asphalt is a key role in the design guide. Therefore it is urgent to get a proper materials database, especially the dynamic modulus of hot mix asphalt. In this research, dynamic modulus test, which is based on aged asphalt binder, has been carried out and proposed the predicted equation of dynamic modulus. Nine different hot mix asphalt with three different asphalt binder have been used for the dynamic modulus test. Short-term aging, which is covers the time for the production of asphalt plant, transportation, lay-down, and compaction, can be simulated at $135^{\circ}C$ with 2 hour curing. Long-term aging has been carried out for a performance period of asphalt pavement. The dynamic modulus of asphalt pavement increases with aging time. As the nominal aggregate size increases, the change of dynamic modulus is not big.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.1-8
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• 2021

This study developed low-cost and high-efficiency pavement condition monitoring technology to produce the key information required for pavement management. A noise and artificial intelligence-based monitoring system was devised to compensate for the shortcomings of existing high-end equipment that relies on visual information and high-end sensors. From idea establishment to system development, functional definition, information flow, architecture design, and finally, on-site field evaluations were carried out. As a result, confidence in the high level of artificial intelligence evaluation was secured. In addition, hardware and software elements and well-organized guidelines on system utilization were developed. The on-site evaluation process confirmed that non-experts could easily and quickly investigate and visualized the data. The evaluation results could support the management works of road managers. Furthermore, it could improve the completeness of the technologies, such as prior discriminating techniques for external conditions that are not considered in AI learning, system simplification, and variable speed response techniques. This paper presents a new paradigm for pavement monitoring technology that has lasted since the 1960s.

• Korean Journal of Organic Agriculture
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• v.26 no.3
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• pp.489-500
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• 2018

Rural Development Administration (RDA) is promoting the AFACI IPM (Asian Food & Agricultural Cooperation Initiative program). AFACI consist of 12 countries including Bangladesh, Cambodia, Thailand, Vietnam and so on. The main goal of the AFACI IPM project is 'Establishment of an international cooperative network for the best management of migratory rice planthoppers and setting data-base of pests occurrence information. As a result of the suvey, Planthoppers were increasing all the way from tillering stage to ripe stage and do not appear to be peak of one or two like korea case. In detail, 1,673 of BPH (Nilaparvata lugens) occurred in survey site of Svay Reang, Cambodia, followed by 1.237 at Dobila, Bangladesh. In the case of White backed planthopper (Sogatella furcifera), 1,163 of WBPH occurred in survey site of Dobila, Bangladesh and 849 WBPH were collected at Hamkuria, Bangladesh. It is expected to verify the occurrence and movement patterns of hoppers among member countries in the future.

• Korean Journal of Weed Science
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• v.31 no.2
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• pp.192-198
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• 2011

This study was conducted to investigate the herbicidal activity against Scirpus planiculmis (SCPPL) which has been reported as resistant biotype on sulfonylurea (SU) herbicides at the west coast reclaimed area first and proliferated continuously at Hwasung and Pyeongtaek in Gyeonggi province, and some Chungnam province. In order to investigate resistance breakability against SCPPL, new rice herbicides containing tefuryltrione [p-hydrophenyl pyruvate dioxygenase (HPPD) inhibitor], pyrimisulfan and triafamone[actolactate synthethase (ALS) inhibitor] were tested. In both lab and field experiments, tefuryltrione GR, 4-HPPD inhibitor showed growth retardation with a bleaching on the young leaves of SCPPL at early time after treatment. However, it restored and regerminated with insufficient control effect. On the other hand, pyrimisulfan+mefenacet SC, triafamone+tefuryltrione GR, and ALS inhibitor showed excellent control effect on SU-resistant SCPPL with growth retardation and necrosis. In particular, pyrimisulfan+mefenacet SC showed excellent controlling effect on SU-resistant SCPPL in regional field experiments.

• Korean Journal of Environmental Agriculture
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• v.2 no.1
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• pp.1-5
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• 1983

A study was undertaken to investigate the persistence of diazinon in two different soils under field conditions. Half-life of diazinon granule(5%) incorporated into soils at a rate of 0.15 ㎏ a.i./l0a was 11 and $9{\sim}12$ days in Suweon and Iri soil under field conditions, respectively. Diazinon residues in brown rice and rice straw harvested from Suweon field were also evaluated by scheduled application intervals. On the basis of maximum residue limit of diazinon in brown rice, it is recommended that the insecticide could be applied upto 15 days before harvest at the limit of 4 spraying times.