• Proceedings of the Korean Quaternary Association Conference
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• 2006.11a
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• pp.23-25
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• 2006

제4기 만빙기에서 후빙기 사이의 기후변화는 인류문명에 있어 정착생활 및 농경활동과 더불어 잉여생산물 저장을 위한 토기제작 등과 같은 생활상의 변화를 가져 온 계기가 되었다(F.M. Chambers, 1993; Guoyu Ren, 1998; Mori Y, 2002; Martin Bell et al., 2004). 식물화석, 화분, 식물규소체 등의 대리자료(proxy data)를 이용하여 이시기의 식생환경을 밝히는 것은 고생태복원분야 뿐 아니라 당시의 환경변수들 을 추정하여 인간활동에 어떠한 영향을 미쳤는지에 대한 중요한 정보를 제공해준다. 그러나 홀로세 초기 환경은 인간에게 지대한 영향을 미쳤으나 후기로 올수록 인간 스스로가 환경을 변화시키는 주체가 되었다(Martin Bell et al., 2004). Meyer&Turner(1994)는 인간활동이 자연적인 영향보다 생물구에 시계열적인 변화를 가져왔다고 하였으며, R.B Singh(1995)는 현재뿐 아니라 과거까지 다양한 인위 적인 간섭이 전지구적인 환경변화를 야기 시키는 주된 원인이라고 하였다. 따라서 환경을 복원한다는 것은 바로 그 지역을 생활 터전으로 삼았던 당시 선사인들의 생활상을 간접적으로 들여다 볼 수 있는 기회를 제공해준다. 현재까지 국내 고고학 유적지에서 이루어진 대부분의 발굴조사는 유물과 유구를 토대로 당시 선사인의 생활상을 밝히는데 중점을 두었으나 최근 인간과 영향을 주고 받았을 환경에 관심을 갖고 이를 통해 역으로 인간활동을 추적하려는 다수의 연구들이 제4기학, 고고학, 지리학, 인류학, 생물학, 농학, 기후학 등 다양한 분야에서 학제간 연구로 진행되고 있다(황상일 등, 1999; 조현종, 2000; 김주용 등, 2002; 최정민, 2004; 윤순옥 등, 2005). 그러나 이러한 연구에 있어서 어떠한 대리자료(proxy data)를 어떻게 고고학 유적지에 적절하게 적용시킬 것인지 대리자료의 조성변화나 값의 해석에 있어서 기후인자와 인간영향을 어떻게 분리해 낼 것인지에 대한 문제점이 남는다. 예를 들어 화분분석의 경우 1차적인 환경변화에 따른 식생조성변화를 반영한다. 인간이 활발한 농경활동을 하게 되면서 주변식생을 제거하게 되고, 제거된 나대지에는 재배작물과 잡초들이 자라게 된다. 그리고 이들 화분은 주변 소택지에 퇴적물과 함께 퇴적되어 화분분석 결과 벼과(科)(Gramineae)와 문화지표수종이라 부르는 여뀌속(屬)(Persicaria), 국화과(科)(Composite), 쑥속(屬)(Artemisia), 쐐기풀속(屬)(Urtica) 등의 화분에 있어 확연한 조성변화를 보여준다. 그러나 화분을 이용한 분석은 토탄층이나 유기질 퇴적물이라는 한정된 토양에서만 분석이 가능하며, 조성변화에 있어서 역시 기후와 인간활동의 영향 모두를 반영하기 때문에 이를 구분해 주는 명확한 기준이 필요하다. 따라서 본 연구에서는 이러한 다양한 대리자료 중 고고학 유적지에 적용 가능한 동식물 화석 및 미화석, 지리, 지질학적 자료에 어떠한 것들을 적용할 수 있는지를 살피고, 몇 가지 대리자료를 중심으로 선사인의 농경활동에 대해 살펴보고자 한다.

• Journal of Conservation Science
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• v.26 no.3
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• pp.341-348
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• 2010

After excavation work of relics, historical site which has historically meaningful, are preserved using the various methods. There are three method in the relocation methods that are original relocation method, the remaining structure-peel method, and soil peel method. The original relocation method is restored after relocating in historical site such as residential site, iron foundry site, kiln site, old mound. The remaining structure-peel method are restored only the feature of exposed remaining structure using polymeric resin, when it is difficult to relocate the entire remaining structure. And soil-peel method is exhibited after peeling in case when soil layers such as grave of old mound, foundation of building site, sedimentary deposit layer, shell heap, and etc. Soil-peel method becomes important historical data of changes according to environment at that time, that is, flooding by storm, traces of fire and living features of that time such as heaps of shells discarded after eating shellfish and living wastes. In particular, in case of soil layer for preparing foundation sites of building by compacting in turn soils with different components such as clay soil, rough sand soil and etc, it becomes important data which can judge foundation technology of that time. It can be said to be an important data preservation method for utilizing these historical data as historical data as well as for the purpose of education, exhibitions and public relations which can be shared not only by experts but also by general public. In this paper, we present the reliable definition of soil-peel method in various preservation methods and explain the using polymer in this method. So, we will come up with the accurate index about this method that is used the eminent analysis method for soil layer.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.3
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• pp.180-190
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• 2014

It has been customary to exclude top 10-20% of velocity profiles in the Acoustic Doppler Current Profiler (ADCP) measurement due to side lobe effects at the boundary. To better understand the mixing in the Yeongsan estuary, the freshwater advection speed (FAS) was recovered from highly contaminated ADCP data near the surface. The velocity profiles were measured by using ADCP at two stations in the Yeongsan estuary during August 2011: one was located in front of the Yeongsan estuarine dam and the other was deployed near Goha Island. The FAS was recovered from the ADCP data set by applying rigorous post-processing methods and compared with the sediment advection speed (SAS). The SAS was determined by the peak time difference of suspended sediment concentration between two stations in the channel, divided by the distance of two stations. The FAS and the SAS showed very similar value when the freshwater discharge was greater than $2.0{\times}10^7$ ton and the SAS was a bit greater when the freshwater discharge was smaller. Since the FAS was on average about 0.8 m/s greater than the velocity at 0.8 of water depth from the bottom, the net discharge, estimated with recovered FAS and integrated over water depth and tidal cycle, was directed seaward during the high discharge contrary to the onshore direction of the net discharge estimated with 0.8 of water depth from the bottom. Moreover, the velocity shear and Richardson number changed when the FAS was used. Thus, the importance of the true FAS is appreciated in the investigation of the surface layer stability. If currents, temperature and salinity were observed for longer time in the future, it could be possible to more accurately understand the formation and decay of stratification as well as the suspended sediment transport processes.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.3
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• pp.74-80
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• 2001

Due to floating marine debris, seabed litters, dead shellfishes and polluted sediments, etc. , which are mainly caused by fishery activities in a large scale around the coastline, expansion of industrialized areas from economic development and drastic increase of free time by the improved standard of living, Korean coast is believed to be cast beyond the self purification of marine ecosystem. Seabed litters, if not remedied in a timely manner, will eventually lead to the overall disorder of benthic ecosystem. Thus, in order to prevent marine ecosystem from being thrown into confusion by seabed litters and to restore ocean environments, it is reasonable to investigate the current status of the seabed litters by carrying out an extensive examination on them and to equip ourselves for marine debris with an systemized tool that provides supports to the building process of an efficient methodology of litters disposal through managing related data appropriately. As an primary step to this goal, a systematic method of investigation is presented in this paper. With this methodology, the present state of the seabed titters is properly understood for the specified list of ports.

• Journal of the Korean GEO-environmental Society
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• v.15 no.5
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• pp.31-37
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• 2014

In situ investigations and laboratory tests using elastic wave have become popular in geotechnical and geoenvironmental engineering. Propagation velocity of elastic wave is the key index to evaluate the ground characteristics. To evaluate this, various methods were used in both time domain and frequency domain. In time domain, the travel time can be found from the two points that have the same phase such as peaks or first rises. Cross-correlation can also be used in time domain by evaluating the time shift amount that makes the product of signals of input and received waveforms maximum. In frequency domain, wave propagation velocity can be evaluated by computing the phase differences between the source and received waves. In this study, wave propagation velocity evaluated by the methods listed above were compared. Bender element tests were conducted on the specimens cut from the undisturbed hand-cut block samples obtained from Block 37 excavation site in Chicago, IL, US. The evaluation methods in time domain provides relatively wide range of wave propagation velocities due to the noise in signals and the sampling frequency of data logger. Frequency domain approach provides relatively accurate wave propagation velocities and is irrelevant to the sampling frequency of data logger.

• Conservation Science in Museum
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• v.4
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• pp.23-32
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• 2003

As the kettle excavated from a site in Hwangnam-dong, Gyeongju was presumed to have been used as a melting crucible in a glass production workplace, we decided to prove its usage by scientific analysis. First, we performed conservation treatment to find the original status of the kettle, and then SEM-EDS and XRD analysis of the five corrosions created on the surface of the kettle. The fragment of the spout, which played a crucial role for the kettle to be considered as a melting crucible, was discovered during the conservation treatment. So the mouth rim of the kettle was restored to perfection. When we observed the microstructure of the metal sample, it was proved to be cast iron gradually cooled without heat treatment. In the corrosion products, the main components were Fe and O and other components such as P, Si, Ca, and S were found. The main compounds were quartz, vivianite, goetheite, akaganite, lepidocrocite, hematite, etc. Although these components were used as raw materials for making glass, these were found not in the melting status but mere raw materials. This can be an evidence to show these site where the kettle was excavated had been a glass production workplace. However, it is not sure that the kettle was used as a melting crucible. Moreover, if we consider the organic mold and sand clay accumulated in the well site when the kettle was excavated at first, we can see this as a formative factor of the corrosions of the kettle. Therefore, we concluded that the kettle is a typical cast iron and was not used as a melting crucible of glass.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.1
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• pp.55-68
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• 2020

In order to investigate the hydraulic characteristics of a boundary layer streaming over the beach cusps appeared in swells prevailing mild seas, we numerically simulated the shoaling process of Edge waves over the beach cusp. Synchronous Edge waves known to sustain the beach cusps could successfully be duplicated by generating two obliquely colliding Edge waves in front of beach cusps. The amplitude A_B and length L_B of Beach Cusp were elected to be 1.25 m and 18 m, respectively based on the measured data along the Mang-Bang beach. Numerical results show that boundary layer streaming was formed at every phase of shoaling process without exception, and the maximum boundary layer streaming was observed to occur at the crest of sand bar. In RUN 1 where the shortest waves were deployed, the maximum boundary layer streaming was observed to be around 0.32 m/s, which far exceeds the amplitude of free stream by two times. It is also noted that the maximum boundary layer streaming mentioned above greatly differs from the analytical solution by Longuet-Higgins (1957) based on wave Reynolds stress. In doing so, we also identify the recovery procedure of natural beaches in swells prevailing mild seas, which can be summarized such as: as the infra-gravity waves formed in swells by the resonance wave-wave interaction arrives near the breaking line, the sediments ascending near the free surface by the Phase II waves orbital motion were carried toward the pinnacle of foreshore by the shoreward flow commenced at the steep front of breaking waves, and were deposited near the pinnacle of foreshore due to the infiltration.