• Geophysics and Geophysical Exploration
• /
• v.14 no.2
• /
• pp.146-151
• /
• 2011

A method to evaluate and to reduce the source- and receiver- consistent noise in a cross-well travel time data was proposed. These systematic noises, which can cause some serious effects on the result of a travel time tomography, can be considered as the source and receiver statics. The method evaluates the statics through a curve-fitting of the first arrival travel times in the common source and common receiver gathers. Feasibility study was conducted on a synthetic data which simulates the cross-well travel time tomography to detect a small scale tunnel in a uniform background medium. First arrival travel times at a given source and receiver points are computed by a raytracing method, and the source consistent- and receiver consistent noises are added to the record. In case of the added noise with rms amounting to 25% of the maximum expected anomalous travel time delays, it is confirmed that the method successfully extracted the noise at the 7th step of iteration.

• Journal of the Korean Society of Costume
• /
• v.42
• /
• pp.207-222
• /
• 1999

This study is a thesis based on the fact that at the end of eighteenth century similar change in hair style appeared in Chosun and France which are located very far almost the opposite side of the earth. We can see that very exaggerated and big hair styles of those days in both countries became exceptionally reduced and changed to practical shapes through (an order prohibiting to make large hair style using wigs) is case of Chosun and through the France Revolution in case of France. Outwardly the abobe mentioned change may seem to be caused by such brave and outward convention as the prohibition order and the revolution. however I think that more basic cause of such change from big and splendid hair styles of those days to simple styles was because of many people's sympathy with the necessity of improving various social and economical problems caused by the luxurious and even prodigal situation of those days before the change and additionally because of such pragmatic thought as Positivism of chosun and illuminism of france. In case of france the change in hair style occurred for such a short period of time around the France Revolution(1789) that we can even that the change occurred in a day. However in case of Chosun such change became fixed at the time of king Suncho prohibiting to make large hair style using wigs (1756-1788) was announced. in case of France such change in hair style was mainly because of change of thought caused by people's self-consciousness. But in case of Chosun under the situation where common people's way of thinking about sumptuous moods and beauty was not changed unvoluntary and compulsory change was asked by the King's order so a lot of time seemed to have been necessary for the change in hair style to become fixed as a nationwide common and general custom.

• ALGAE
• /
• v.23 no.4
• /
• pp.295-300
• /
• 2008

Seaweed biomass was estimated using a nondestructive method in the rocky subtidal zones in Munseom, Jeju Island, Korea from July 2006 to April 2008. Seasonal samplings were done at the depth of 1, 5, 10 m using 50 x 50 cm quadrat. Mean biomass was comprised of 2,784 g wet wt m$^{-2}$ and the biomass values varied seasonally from 1,176 g wet wt m$^{-2}$ to 4,217 g wet wt m$^{-2}$ with the highest point in April. Biomass reached maximum at 5 m depth in spring, but was shifted to 10 m depth in summer. Common seaweeds appeared year round in Munseom were Codium minus, Ecklonia cava, Sargassum spp., articulated corallines and Plocamium telfairiae. Among them, E. cava showed the highest biomass (average of 1,288 g wet wt m$^{-2}$), comprising 4% of total biomass. Only 12 species’' biomass covered 98% of total value, which indicated the contribution of few common species to algal community. Seaweed biomass in Munseom represented one of the highest values in coastal regions in Korea.

• Geophysics and Geophysical Exploration
• /
• v.9 no.2
• /
• pp.171-175
• /
• 2006

Gravity reduction and Bouguer anomaly are frequently misunderstood by many geoscientists as follows; the observed gravity is reduced to a common datum plane, so that gravity effects by all materials above the datum is removed, therefore, Bouguer anomaly is located on the datum plane. In reality, Bouguer anomaly does not lie on a common datum plane, but is difference between observed gravity and reference gravity at the actual point of measurement. Commonly used gravity reduction formulas are approximate formulas. Here, we introduce complete formulas, and suggest to use them for more accurate results. We also suggest to use not the geoid but the reference ellipsoid as the vertical datum.

• Progress in Superconductivity and Cryogenics
• /
• v.20 no.2
• /
• pp.1-5
• /
• 2018

Arsenic (As) is one of the elements having most harmful impact on the human health. Arsenic is a known carcinogen and arsenic contamination of drinking water is affecting on humans in many regions of the world. Adsorption has been proved most preferable technique for the removal of arsenic. Many researchers have studied various types of solid materials as arsenic adsorbent, and iron oxide and its modified forms are considered as the most effective adsorbent in terms of adsorption capacity, recovery, and economics. However, most of all iron oxides have small surface area in comparing with common adsorbents in environmental application such as activated carbon but the activated carbon has weak sorption affinity for arsenic. We have used an activated carbon as base adsorbent and iron oxide coating on the activated carbon as high affinity sorption sites and giving magnetic attraction ability. In this study, adsorption properties of arsenic and magnetic separation efficiency of the magnetized activated carbon (MAC) were evaluated with variable iron oxide content. As the iron oxide content of the MAC increased, adsorption capacity has also gradually increased up to a point where clogging by iron oxide in the pore of activated carbon compensate the increased sorption capacity. The increase of iron oxide content of the MAC also affected magnetic properties, which resulted in greater magnetic separation efficiency. Current results show that magnetically modified common adsorbent can be an efficiency improved adsorbent and a feasible environmental process if it is combined with the magnetic separation.

• Korean Journal of Acupuncture
• /
• v.40 no.2
• /
• pp.33-43
• /
• 2023

Objectives : Floating acupuncture (FA) is a kind of newly developed acupuncture technique that contains its own apparatus. The technique has unique points that the body of the acupuncture needle stays intradermal space and manipulation is performed by shaking the needle horizontally; after manipulation, part of the needle remained in the intradermal space for 2~3 days. FA is not a common acupuncture methodology while various clinical study claims its efficacy on musculoskeletal disorders. In this study, the authors aimed to enhance the use of FA by comparing related theories. Methods : The authors reviewed classics, books, and articles related to FA, Meridian Muscle (MM), Myofascial Pain Syndrome (MPS), and Wrist-Ankle Acupuncture (WAA), and compared its characteristics by related theory, related symptoms, apparatus, and performing procedures. Results : FA was related and had various common parts with MM, MPS, and WAA, however, there were unique parts in the manipulation, apparatus, and stimulation location. FA is based on MM and MPS which pointing 'ashi points' or 'trigger points' as a treating target while FA does not stimulate the points directly. FA also targets subcutaneous space by inserting the needle horizontally as WAA does, while FA remains the needle handle part in the subcutaneous area for 2~3 days for more stimulation. Conclusions : FA has a unique manipulation procedure and potential benefit for musculoskeletal disorders despite the crude theological base written by Fu himself. Thus, developing a new explanation and patient-friendly methodology/apparatus is required for further down-to-earth studies.

• Journal of the Korean earth science society
• /
• v.25 no.7
• /
• pp.558-564
• /
• 2004

This research investigated the connection between science textbook contents in Democratic People's Republic of Korea (DPRK) and those in Republic of Korea (ROK). Both text books in the field of earth science were analyzed and classified into 70 categories based on the Third International Mathematics and Science Study (TIMSS). Comparison was specifically made between the elementary and middle school text books of both countries; the result are as follows: First, the scope and the level of the textbooks' contents are quite different between DPRK and ROK. Text books in the South are much limited in concepts and terms than those in the North. In contrast, textbooks in DPRK are written mainly to explain concepts. Second, there are many common contents of the textbooks in DPRK and Republic of Korea. The level and scope of the contents in Republic of Korea are more inquisitive, quantitative and detailed than those in DPRK. Third, we found content connections in science textbooks between primary and secondary schools in both countries: 27 items (38.5%) are related in ROK and 19 items (27.1%) in DPRK.

• Journal of the Mineralogical Society of Korea
• /
• v.28 no.2
• /
• pp.109-126
• /
• 2015

Because fault gouge developed at the center of fault is recognized as one of the most important weak sites, it is evident that clay mineralogy and physical properties greatly affect the rock stability. The purpose of this study is to establish the relationship of mineralogy and physical factors that control rock stability in fault zones. We analyzed a total of 51 samples from 16 main faults which were selected from a Korea fracture map, using XRD, SEM, and physical analyses like unit weight, friction and cohesion properties. Though it is considered that the most common clay minerals comprising fault gouge are kaolinite, illite and smectite, clay mineralogy slightly varies depending on lithology: illite > smectite > kaolinite and chlorite in volcanic rocks, kaolinite and chlorite > illite > smectite in sedimentary rocks, and illite > smectite > kaolinite and chlorite in abundance, respectively. Friction angle decreases with increasing clay content. Cohesion increases with increasing clay content below the 45 % region while it decreases with increasing clay content at the region higher than 45%, with some scatters in the data. It is likely that these results are ascribed to the physical heterogeneity of fault gouges with varying content of different clay minerals.

• Journal of Science Education
• /
• v.44 no.1
• /
• pp.1-14
• /
• 2020

In this study, we analyzed the written and drawn explanations of thirty elementary school pre-service teachers in order to examine their perception on the seasonal length of day and night. The main findings are as follows: First, pre-service teachers used the most common term in the description of the texts, such as meridian altitude, axis of rotation, and revolution, and there were more misconceptions in the drawn explanation than in the written explanation. Second, by analyzing the pre-service teachers' perceptions by combining written and drawn explanations, it is possible to detect scientific errors that the distance between the Earth and the Sun is closer when the axis of rotation is tilted in relation to the revolution and seasonal changes due to changes in the orbital radius of the Earth. In addition, there have been types of explanations such as seasonally changing meridian altitudes related to the rotation of the Earth but no change in the location of the Sun. Based on the results of the analysis, we discussed the lack of experience in constructing an explanatory system of specific phenomena using scientific knowledge, lack of observational experiences about natural phenomena, and lack of exposure to other explanatory systems that cause cognitive conflicts. We hope that it will be concrete and practical help to improve the understanding of pre-service teachers in the science domain of primary teacher training program.

• Journal of Cadastre & Land InformatiX
• /
• v.47 no.1
• /
• pp.111-126
• /
• 2017

Small-scale UAS(Fusion technique of Unmanned Aerial Vehicles platform and Sensors, 'sUAS') opens various new applications in construction fields and so becoming progressively common due to the considerable potentials in terms of accuracy, costs and abilities. The purpose of this study is that the investigation of the validation on the utilization of sUAS for earth stockpile volume calculations on sites. For this, generate 3D models(DSM) with sUAS aerial images on an cone shaped soil stockpile approximately $270m{\times}300m{\times}20m$, which located at Baegot Life Park in Siheung-si, compared stockpile volume estimates produced by sUAS image analysis, against volume estimates obtained by GNSS Network-RTK ground surveying method which selected as the criteria of earth stockpile volume. The result through comparison and examination show(demonstrate) that there was under 2% difference between the volume calculated with the GNSS Network RTK data and the sUAV data, especially sUAS imaged-based volume estimate of a stockpile can be greatly simplified, done quickly, and very cost effective over conventional terrestrial survey methods. Therefore, with consideration of various plan to assess the height of vegetation, sUAS image-based application expected very useful both volume estimate and 3D geospatial information extraction in small and medium-sized sites.