• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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• pp.151-162
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• 1987

The author obtained the computed tomograms around the condylar head from 10 normal subjects and 5 patients having clicking condylar head from 10 normal subjects and 5 patients having clicking sound or limitation of mouth opening by using a Hitachi-W 500. And then. the author had the axial analysis of condyle position and sagittal analysis of that after sagittal reformation on centric occlusion and 18㎜ interincisal opening. Transcranial view and submentovertex view were taken and compared with computed tomographic view. The obtained results were as follows: 1. Median angle of long axis of condylar head was 17 degrees on centric occlusion and the angles of long axis of both condylar heads were reduced symmetrically on 18㎜ interincisal opening in normal group. however. in the patient group, the affected side of condyle heads showed greater change in the angle on 18㎜ interincisal opening. 2. In the patient group, the condyle head of affected side was located superiorly to that of normal side on centric occlusion and the discrepancy of condular positional height was increased after 18㎜ interincisal opening. 3. The distances from medial pole of condylar head to triangular fossa of temporal bone were same on both right and left side in normal group, however, in the patient group, the distance of affected side was wider than that of opposite side on centric occusion and became narrower than the opposite side on 18㎜ interincisal opening. 4. The distances of posterior joint space were same on both right and left side. The distance t lateral pole 1/3 of condyle head was similar to that on transcranial view on centric occlusion in normal group. 5. The distances of posterior joint space were narrower in patient group than in normal group. 6. Conclusively, the affected condylar head of patient showed postero-latero-superior displacement on centric occlusion and larger range of rotational movement on 18㎜ interincisal opening.

• Journal of Astronomy and Space Sciences
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• v.33 no.1
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• pp.29-36
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• 2016

The East African ionosphere (3°S-18°N, 32°E-50°E) was mapped using Total Electron Content (TEC) measurements from ground-based GPS receivers situated at Asmara, Mekelle, Bahir Dar, Robe, Arbaminch, and Nairobi. Assuming a thin shell ionosphere at 350 km altitude, we project the Ionospheric Pierce Point (IPP) of a slant TEC measurement with an elevation angle of >10° to its corresponding location on the map. We then infer the estimated values at any point of interest from the vertical TEC values at the projected locations by means of interpolation. The total number of projected IPPs is in the range of 24-66 at any one time. Since the distribution of the projected IPPs is irregularly spaced, we have used an inverse distance weighted interpolation method to obtain a spatial grid resolution of 1°×1° latitude and longitude, respectively. The TEC maps were generated for the year 2008, with a 2 hr temporal resolution. We note that TEC varies diurnally, with a peak in the late afternoon (at 1700 LT), due to the equatorial ionospheric anomaly. We have observed higher TEC values at low latitudes in both hemispheres compared to the magnetic equatorial region, capturing the ionospheric distribution of the equatorial anomaly. We have also confirmed the equatorial seasonal variation in the ionosphere, characterized by minimum TEC values during the solstices and maximum values during the equinoxes. We evaluate the reliability of the map, demonstrating a mean error (difference between the measured and interpolated values) range of 0.04-0.2 TECU (Total Electron Content Unit). As more measured TEC values become available in this region, the TEC map will be more reliable, thereby allowing us to study in detail the equatorial ionosphere of the African sector, where ionospheric measurements are currently very few.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.2
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• pp.12-21
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• 2013

This study developed searching network reduction algorithm for reduce shortest path searching time. Developed algorithm is searching nodes that have the including possibility of less weights path than temporal path that consists minimum number of nodes and minimum sum of the straight line distances. The node that has the including possibility of shortest path is the node that the sum of straight line distance from start node and straight line distance to target node is less than the value that temporary path's weights divided by minimum weights units. If searching network reconstitutes only these nodes, the time of shortest path searching will be reduced. This developed algorithm has much effectiveness that start node and target node is close in large network.

• Journal of the Korean Society for information Management
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• v.29 no.1
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• pp.135-156
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• 2012

The purpose of this study is to ascertain librarian's perceptions on their users' library access and its patterns. Interviews with seven library staff reveal physical accessibility issues including spatial relationships between libraries and other facilities such as shopping malls and schools, travel distance, transportation mode, and temporal perspectives of library access. The results from the interviews corroborate the findings from secondary analysis using household travel data. However, interviewees do not have a clear picture of how much their users travel and spend to access their libraries. This is true, even though these factors are critical to analyze physical accessibility. Based on the findings, this study makes recommendations to improve the accessibility of public libraries. Suggestions include the concept of sponsorships with other facilities, the placing of material drop-boxes on the main route, and providing library programs during lunch time.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.2
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• pp.89-93
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• 2008

Goldfish were exposed to radioactive isotope $^{18}F$, which is used for positron emission tomography (PET). $^{18}F$ is created when the oxygen in water combines with hydrogen on exposure to positrons accelerated by a cyclotron. The temporal change in intestine contractility was measured by physiograph after the exposure to $^{18}F$. The distance between the goldfish and 580 mCi of $^{18}F$ was approximately 4 cm and the exposure was for 4 hrs. The absorption level calculated from the distance, exposure time, and half-life of $^{18}F$ was approximately 2 Gy. The contractile activity of goldfish intestine was lowest on the first day and increased gradually to 100% of the control level by a period of between 5 and 36 days.

• Phonetics and Speech Sciences
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• v.11 no.3
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• pp.31-38
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• 2019

The current electromagnetic articulography study analyzes several articulatory measures and examines whether, and if so, how they are interconnected, with a focus on cluster types and an additional consideration of speech rates and morphosyntactic contexts. Using articulatory data on non-assimilating contexts from three Seoul-Korean speakers, we examine how speaker-dependent gestural overlap between C1 and C2 in a low vowel context (/a/-to-/a/) and their resulting intergestural coordination are realized. Examining three C1C2 sequences (/k(#)t/, /k(#)p/, and /p(#)t/), we found that three normalized gestural overlap measures (movement onset lag, constriction onset lag, and constriction plateau lag) were correlated with one another for all speakers. Limiting the scope of analysis to C1 velar stop (/k(#)t/ and /k(#)p/), the results are recapitulated as follows. First, for two speakers (K1 and K3), i) longer normalized constriction plateau lags (i.e., less gestural overlap) were observed in the pre-/t/ context, compared to the pre-/p/ (/k(#)t/>/k(#)p/), ii) the tongue dorsum at the constriction offset of C1 in the pre-/t/ contexts was more anterior, and iii) these two variables are correlated. Second, the three speakers consistently showed greater horizontal distance between the vertical tongue dorsum and the vertical tongue tip position in /k(#)t/ sequences when it was measured at the time of constriction onset of C2 (/k(#)t/>/k(#)p/): the tongue tip completed its constriction onset by extending further forward in the pre-/t/ contexts than the uncontrolled tongue tip articulator in the pre-/p/ contexts (/k(#)t/>/k(#)p/). Finally, most speakers demonstrated less variability in the horizontal distance of the lingual-lingual sequences, which were taken as the active articulators (/k(#)t/=/k(#)p/ for K1; /k(#)t/

• Journal of Advanced Navigation Technology
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• v.27 no.2
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• pp.209-213
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• 2023

Currently, 2.4 GHz and 5 GHz bands are used as frequencies for drone operation. In December 2019, the Ministry of Science and ICT newly allocated the 433 MHz band for the invisible long-distance operation of drones. However, since the 433 MHz band is the same as the previously allocated frequency band for amateur radio communication, interference cannot be avoided. Therefore, as a prerequisite for the development of a drone operation system based on the 433 MHz band, interference avoidance technology for this frequency band must be developed and applied. In this paper, we report the results of measurement and analysis of 433 MHz band signals necessary for the development of interference avoidance and reduction technologies for 433 MHz signals. The measurement and analysis of the 433 MHz band signal are performed through the spectrum measured at 5-minute intervals at three locations. Since the measurements and analyzes performed in this study considered spatial characteristics, temporal characteristics, and traffic characteristics, it is considered to be the basic data necessary for the development of interference avoidance technology in the 433 MHz band.

• Journal of the Korean Geographical Society
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• v.42 no.4
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• pp.469-487
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• 2007

Grain-Size Trend Analysis is the methodology to identify net sediment transport pathways, based on the assumption that the movement of sediment from the source to deposit leaves the identifiable spatial pattern of mean, sorting, and skewness of grain size. It can easily be implemented with low cost, so it has great potentials to contribute to geomorphological research, whereas it can also be used inadequately without recognition of its limitations. This research aims to compare three established methods of grain-size trend analysis to search for the adequate way of application, and also suggest the research tasks needed in improving this methodology 1D pathway method can corporate the field experience into analyzing the pathway, provide the useful information of depositional environments through X-distribution, and identify the long-term trend effectively. However, it has disadvantage of the dependence on subjective interpretation, and a relatively coarse temporal scale. Gao-Collins's 2D transport vector method has the objective procedure, has the capability to visualize the transport pattern in 2D format, and to identify the pattern at a finer temporal scale, whereas characteristic distance and semiquantitative filtering are controversial. Le Roux's alternative 2D transport vector method has two improvement of Gao-Collins's in that it expands the empirical rules, considers the gradient of each parameters as well as the order, and has the ability to identify the pattern at a finer temporal scale, while the basic concepts are arbitrary and complicated. The application of grain sire trend analysis requires the selection of adequate method and the design of proper sampling scheme, based on the field knowledge of researcher, the temporal scale of sediment transport pattern targeted, and information needed. Besides, the relationship between the depth of sample and representative temporal scale should be systematically investigated in improving this methodology.

• Animal cells and systems
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• v.1 no.2
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• pp.329-335
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• 1997

The final pattern of the skeletal muscle of a vertebrate depends on the position-specific behavior of the muscle precursor cells during early developmental process and the abdominal muscle is made of cells which migrate a relatively long distance from their original tissue, myotome of dorsal mesoderm. We report the spatia-temporal migration pattern of abdominal muscle in Xenopus laevis by in situ hybridization and immunohistological studies. Shortly after hatching tadpole stage (stage 31/32), a group of myotomal cells detaches from the lower tip of the second somite and migrates ventrally to the lower position of abdomen. At stage 34/35, a second cell group migrates away from the third somite. Total 7 myotomal cell groups migrate ventrally one by one from the second to eighth myotome along their own pathways through the cell free space located between epidermis and subepidermal layer of the abdomen. During migration, the sizes of the cell groups (abdominal muscle anlagens) are increased to several tens fold. Around stage 40 all the abdominal muscle anlagens reaches their final positions and are interconnected side by side rostrocaudally. They are also connected to other types of muscles, forming a large multisegmented abdominal muscle. Heat shock study suggests that the disruption of segmentation of somites does not block the detachment of abdominal muscle anlagen, though the treatment gave stage- and dosagedependent effects on the migration speed.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.E
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• pp.55-62
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• 1995

The distribution of airborne mercury was investigated from several districts of Seoul, five other major cities and two rural areas during the period April, 1994 to March, 1995. The method used in this study involves absorption of gaseous mercury on CHromosorb$^R$ A coated with gold and detection by cold vapor atomic absorption spectroscopy. The atmospheric mercury concentrations in Seoul ranged from N.D. to 120.17 ng m$^3$ (mean 27.01 $\pm 9.42 ng m^{-3}, N=139$), while those in rural areas ranged from 1.72 to 8.24 ng $m^{-3} (mean 4.57 \pm 3.07 ng m^{-3}, N=5$). The spatial distribution characteristics of mercury distribution in urban air were examined by comparing mercury levels as a function of the distance from the urban center. Temporal distribution trends of airborne mercury were also studied using the monthly mean mercury data of various districts in Seoul. The atmospheric mercury concentration around Mokdong wastes incinerator in Seoul were also investigated.