• Economic and Environmental Geology
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• v.37 no.2
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• pp.185-193
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• 2004

A physical model experiment was conducted using a sand and gravel-filled tank model, to investigate the influence on the GPR response of LNAPL vapor phase effects in the unsaturated zone and of residual phase of LNAPL trapped in the saturated zone. Background measurements of GPR were made with only water in the tank using a fluctuating water table model. Gasoline was, then, injected into the bottom of the model tank to simulate a subsurface discharge from a leaking pipe or tank at depth, obtaining GPR data with rising and lowering of water table. Results from the experiment show the GPR sensitivity to the changes in the moisture content in the vadose zone and its effectiveness for monitoring minor fluctuation of the water table. The results also demonstrate a potential of GPR for monitoring possible vapor phase effects of volatile hydrocarbons in the vadose zone as a function of time, and for detecting the effects of residual phase of hydrocarbons in the water saturated system. In addition, the results provide the basis for a strategy that has the potential to successfully detect and delineate residual LNAPL contamination in the water-saturated system at field sites where the conditions are similar to those simulated in the physcial models described herein.

• The Journal of Engineering Geology
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• v.15 no.1
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• pp.41-55
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• 2005

This research is aimed at investigating the ground characterization of the Cheongju granite area using the geophysical methods. Test site was chosen from the building site in Chungbuk University, Chongju, Chungbuk province. Furthermore, geophysical methods are employed on the outcrops in the east to map the distribution of fault and intrusion and reveal the degree of weathering. The subsurface structure mapped from seismic re-fraction survey mainly consists of two units of weathered soil and rock. Threshold of the units were determined on the basis of seismic velocity of 800 m/s, supported from the standard classification table. From the results of standard penetrating test(SPT), these units are found to show medium-high and high density, respectively. Weathering soil is subdivided in unsaturated layer and saturated layer with thresholds of seismic velocity (500 m/s) and resistivity (200 ohm-m). In particular, unsaturated layer is again classified into dry and wet portions using the GPR section. The boundary between unsaturated and saturated weathering soils corresponds to the groundwater table at depth of approximately 5～6.2 m, which is well correlated with the one from drill-core data. However, bedrock is not delineated by geophysical methods. In the GPR section, fault and intrusion observed on the outcrop are revealed not to extend to the building site. With respect to weathering degree, the outcrop characterized by low resistivity and velocity corresponds to the grade of 'completely weathered' from the geotechnical investigations.

• The Journal of Engineering Geology
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• v.25 no.3
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• pp.349-356
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• 2015

Although geophysical methods are useful and generally provide valuable information about the subsurface, it is important to recognize their limitations. A common limitation is the lack of sufficient contrast in physical properties between different layers. Thus, multiple methods are commonly used to best constrain the physical properties of different layers and interpret each section individually. Ground penetrating radar (GPR) and shallow seismic reflection (SSR) methods, used for shallow and very shallow subsurface imaging, respond to dielectric and velocity contrasts between layers, respectively. In this study, we merged GPR and SSR data from a test site within the Cheongui granitic mass, where the water table is ~3 m deep all year. We interpreted the data in combination with field observations and existing data from drill cores and well logs. GPR and SSR reflections from the tops of the sand layer, water table, and weathered and soft rocks are successfully mapped in a single section, and they correlate well with electrical resistivity data and SPS (suspension PS) well-logging profiles. In addition, subsurface interfaces in the integrated section correlate well with S-wave velocity structures from multi-channel analysis shear wave (MASW) data, a method that was recently developed to enhance lateral resolution on the basis of CMP (common midpoint) cross-correlation (CMPCC) analysis.

• Journal of the Korean Society for Library and Information Science
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• v.45 no.2
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• pp.209-228
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• 2011

Web search behavior has evolved. People now search using many diverse information devices in various situations. To monitor these scattered and shifting search patterns, an improved way of learning and analysis are needed. Traditional web search studies relied on the server transaction logs and single query instance analysis. Since people use multiple smart devices and their searching occurs intermittently through a day, a bundled query research could look at the whole context as well as penetrating search needs. To observe and analyze bundled queries, we developed a proprietary research software set including a log catcher, query bundling tool, and bundle monitoring tool. In this system, users' daily search logs are sent to our analytic server, every night the users need to log on our bundling tool to package his/her queries, a built in web survey collects additional data, and our researcher performs deep interviews on a weekly basis. Out of 90 participants in the study, it was found that a normal user generates on average 4.75 query bundles a day, and each bundle contains 2.75 queries. Query bundles were categorized by; Query refinement vs. Topic refinement and 9 different sub-categories.

• Korean Journal of Acupuncture
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• v.31 no.3
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• pp.136-145
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• 2014

Objectives : The purpose of this randomized, placebo-controlled, cross-over trial was to examine how acupuncture treatment at Shinmun(HT7) affects the brain activity and the autonomic nervous system(ANS), using electroencephalograms(EEG) and heart rate variability(HRV). Methods : Eighteen healthy volunteers participated in two separate experiments: in each experiment, either real acupuncture(RA) or non-penetrating sham acupuncture(SA) was applied at HT7 in random sequences to each person. The EEG and HRV measurements were conducted simultaneously before and during the acupuncture stimulation for 5 minutes, respectively. Resulting EEG and HRV parameters were compared between RA and SA groups. To assess differences according to the stress levels for participants, subgroup analysis was performed based on the results of the stress response index questionnaire. Results : In the results, acupuncture stimulation at HT7 increased ${\alpha}$ band in EEG. In the HRV analysis, heart rate was decreased significantly but HF and RMS-SD were increased in the RA group, compared with those of the SA group. In the subgroup analysis by stress level, participants in the RA group with high stress exhibited an increased in ${\alpha}$ band in their EEG while the low stress participants showed decrease or little increase in the band. For the SA group, ${\alpha}$ band reported relatively moderate changes in all channels. Conclusions : Our results showed that acupuncture induces changes in brain activation and the ANS. Acupuncture was related to the activation of the parasympathetic nervous system. The brain activities of the participants were different depending on the stress level.

• Korean journal of communication and information
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• v.63
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• pp.5-25
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• 2013

Korean society suffers from severe divisions represented by bi-polarization and collapse of the middle class. Intensive demanding on expanding social welfare budget has emerged in accordance with such a dramatic shift. Social consensus moving toward well-financed welfare policy, however, happens to meet political opposition supported by the discourse of fiscal soundness. This paper thus pays particular attention to deciphering the discursive structure in way of understanding how discourses bring public policy into play. For this purpose, news articles about fiscal soundness collected from 8 national newspapers have been analyzed in terms of frame, attitude, perspective and world view. Research results show, first of all, that there exist persistent competition between two frames identified as 'reduced tax with fiscal discipline' and 'increased tax with welfare money.' While the 'reduced tax' frame favors in maintaining tax cut at the expense of welfare budjet, the frame of 'increased tax' supports such arguments as the flexible employment of fiscal soundness and prosperity of national community helped by widening tax revenues. Also did these frames include a number of sub-frames like welfare populism, partisan politics, trickle down effect, tax bonanza for the rich, universal welfare and market over-reactions in order to bolster its logical authority. Media's active taking a part in penetrating supportive frames in line with political stance was found as well. Taking into account both the discursive structure upheld by frames and politics materialized by the media, the authors argue that public policies should be considered more as discourse than fixed reality. Shedding additional light on understanding the interplay among public opinion, policies and media discourse is of another importance for further study.

• Geophysics and Geophysical Exploration
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• v.20 no.2
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• pp.61-71
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• 2017

Recently, ground-penetrating radar (GPR) surveys have been actively carried out for precise subsurface void investigation because of the rapid increase of subsidence in urban areas. However, since the interpretation of GPR data was conducted based on the interpreter's subjective decision after applying only the basic data processing, it can result in reliability problems. In this research, to solve these problems, we analyzed the difference between the events generated from subsurface voids and those of strong diffraction sources such as the buried pipeline by applying the edge detection technique, which is one of image processing technologies. For the analysis, we applied the image processing technology to the GRP field data containing events generated from the cavity or buried pipeline. As a result, the main events by the subsurface void or diffraction source were effectively separated using the edge detection technique. In addition, since subsurface voids associated with the subsidence has a relatively wide scale, it is recorded as a gentle slope event unlike the event caused by the strong diffraction source recorded with a sharp slope. Therefore, the directional analysis of amplitude variation in the image enabled us to effectively separate the events by the subsurface void from those by the diffraction source. Interpretation based on these kinds of objective analysis can improve the reliability. Moreover, if suggested techniques are verified to various GPR field data sets, these approaches can contribute to semiautomatic interpretation of large amount of GPR data.

• Food Science and Preservation
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• v.11 no.2
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• pp.263-268
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• 2004

Two field cooling tests were conducted to evaluate the cooling characteristic of paddy with a prototype grain cooler. The first test was carried out during summer season in a steel bin with 180.3ton of paddy at Sunchon. And the second test was carried out during harvesting season in a steel bin with 272.2ton of paddy at Ulsan. At the first test, initial paddy temperature of 23.6$^{\circ}C$ was dropped to 14$^{\circ}C$, and initial moisture content of 19.9% was dropped to 19.3% after 52.5 hours of cooling. At the second test, initial paddy temperature of 16.1$^{\circ}C$ dropped to 5.5$^{\circ}C$ after 78.0 hours of cooling. And, at the first test, the average air flow rates of chilled air leaving the grain cooler and penetrating the grain layer were 77.5 ㎥/min and 42.5 ㎥/min, respectively. To prevent leakage of chilled air from plenum chamber of steel bin, which was about 45% of the average air flow rates of chilled air leaving the grain cooler, a proper method was required. The average total power consumption at the first test during summer was 22.1 ㎾ with control of fan damper. At the second test, it was 17.4 ㎾ due to controlling the capacity of compressor with unloading solenoid valve and changing the flow rates of hot refrigerant gas flowing into evaporator and reheater from compressor, resulting in 27% reduction of energy consumption.

• Korean Journal of Heritage: History & Science
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• v.52 no.4
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• pp.264-271
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• 2019

Cheomseongdae in Gyeongju, known as an astronomical observatory, is a cultural monument with great historical, academic, and artistic value, as its unique shape is preserved well in its original form. The outer structure, ground stability, and seismic reliability of Cheomseongdae have been assessed by numerous researchers through various scientific methods, but research on the underground structure has been insufficient. This paper contains detailed models of the underground structure of Cheomseongdae interpreted in 2D and 3D images based on the data acquired through GPR surveys conducted of features in and around the base of Cheomseongdae. As a result, the existence of twelve small features arranged in a circle, although only about half of them remain, was confirmed at a depth of 0.4 - 0.6m. Furthermore, a structure three bays long (north-south direction) and four bays wide (east-west direction) was detected beneath Cheomseongdae at the depth of 0.7 - 1.0m. Other than 2 layers of foundations as is known, a square structure with the dimensions of 7m × 7m is situated at a depth of 0.6m, directly under Cheomseongdae, and what is reading that is expected to be the foundation structure of Cheomseongdae was detected and confirmed. This foundation structure is circular with a diameter in the east-west direction of 11m and in the north-south direction of 12m. The northern, western, and eastern edges of this foundation structure are about 1m away from the foundation of Cheomseongdae, whereas the the south side extends to about 5m wide.

• Journal of the Korean association of regional geographers
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• v.16 no.1
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• pp.34-47
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• 2010

The purpose of this study is to investigate the actual condition of commercial use of housing site in residential development complexes, and to derive effective future development plan by analyzing the influence of penetrating factors of commercial use. The foJlowing are the results of the analysis. First, characteristics of roads showed that the wider the widths of roads adjoining individual lots have more influences on commercial use penetration. This means that non-residential facilities tend to be located on regions where frequencies of uses are high, preferring regions having good transportation accessibility. Second, characteristics of adjacent usage showed that the distances of common housing, neighborhood facilities, schools to single-detached residential units acted as a factor for higher penetration ratio of commercial use when they were closer.ors an opposite, it showed as distances to parks were further, the penetration ratio were higher. This can be inferred that the condition of detached houses located closer to parks have pleasure environment, and act as a factor preventing commercial use penetration. Third, the official land price presents as a form of quality, as the analysis showed that the higher official land price, the more it acts as a factor increasing the penetration ratio of commercial use.