• Geophysics and Geophysical Exploration
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• v.11 no.1
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• pp.15-25
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• 2008

Ocean-bottom seismometer (OBS) positions are one of the key parameters in an OBS-airgun seismic survey for crustal structure study. To improve the quality of these parameters, we have developed a new method of determining OBS positions, using airgun shot data and bathymetric data in addition to available distance measurements by acoustic transponders. The traveltimes of direct water waves emitted by airgun shots and recorded by OBSs are used as important information for determining OBS locations, in cases where there are few acoustic transponder data (<3 sites). The new method consists of two steps. A global search is performed as the first step, to find nodes of the bathymetric grid that are the closest to explaining the observed direct water-wave traveltimes from airgun shots, and acoustic ranging using a transponder system. The use of precise 2D bathymetric data is most important if the bottom topography near the OBS is extremely rough. The locations of the nodes obtained by the first step are used as initial values for the second step, to avoid falling into local convergence minima. In the second step, a non-linear inverse method is executed. If the OBS internal clock shows large drift, a secondary correction for the OBS internal clock is obtained, as well as the OBS location, as final results by this method. We discuss the error and the influence of each measurement used in the determination of OBS location.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.346-346
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• 2017

In Northern Laos, maize is cultivated in continuous cropping without fertilizer, fallowing nor any other soil conservation practice. It is expected that this inadequate management in maize cultivation will degrade soil and decrease yield. However, there is limited information about the change of soil condition and yield under continuous maize cultivation. We tried to evaluate the change of soil condition and yield under continuous maize cultivation in Northern Laos. Our study was conducted in farmer's flat and slope fields in Sainyabuli province where maize cultivation had been introduced earlier than the other provinces of Northern Laos. Our study was conducted in 21 fields in 2014, and in 19 fields in 2015. We analyzed grain yield and soil characteristic (total carbon (TC), total nitrogen (TN), available phosphorus (Av-P), exchangeable cation, pH, soil texture) at 3 places in each field. The 3 places were set at different elevation level (lower position, middle position, upper position) in slope fields. Further, the period of continuous maize cultivation and crop management practice were investigated. Then, by evaluating the relation between the period of continuous maize cultivation and yield and the soil characteristics, the effect of maize cultivation was estimated. Crop management practices were similar among the investigated fields. Maize was cultivated in rain season. Grain seed and cob were harvested on September or October, but shoot was left on the fields. No crop was cultivated during dry season. Fertilization and fallowing has never been conducted under continuous maize cultivation. On the other hand, the period of maize cultivation was different among the fields, and ranged from 2 years to 30 years. In the slope fields, as the period of continuous maize cultivation was longer, the contents of TC and TN were lower at all 3 positions, Av-P content was lower at the upper position, exchangeable potassium (Ex-K) content was lower at the middle and the upper positions. The other soil characteristics weren't related with the period of maize cultivation in the slope fields. In contrast, soil characteristics weren't related with the period of maize cultivation in the flat fields. Yield was lower as the period of maize cultivation was longer at the upper position of the slope fields. At middle position of slope fields, yield tended to be low with increase of the period of maize cultivation. In contrast, yield wasn't related with the period of continuous maize cultivation in flat fields. From the results about crop management, it was presumed that the period of maize cultivation was one of the main factors causing the difference of yield and soil characteristics among the fields. Therefore, from the result of yield and soil condition, it was considered that the continuous maize cultivation decreased soil productivity in the slope fields with decline of TC, TN, Av-P, Ex-K and yield at upper position of slope fields, and decline of TC and TN in the other positions in Sainyabuli province.

• Horticultural Science & Technology
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• v.32 no.4
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• pp.440-447
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• 2014

For this analysis, canopies of slender-spindle 'Hongro'/M9 apple trees were divided into 4 positions: upper, lower, exterior, and interior parts. The photosynthetic rate was highest in the external part of the upper canopy of the tree, where it was 4.5 times higher than in the internal part of the lower canopy. This difference was closely associated with differences in light penetration based on canopy position. Analysis of leaf growth characteristics showed that the leaves situated in the internal part of the canopy were larger and thinner than those in the external part of the canopy. The difference in leaf thickness was mainly due to thickness of the primary layer of palisade tissues (68.5 and $110.3{\mu}m$ for internal and external leaves, respectively). Fruit weight and quality were closely related to the extent of light penetration. Fruit weight, soluble solid content, and red skin color were higher in the fruits from the external part of the canopy. Thus, fruit maturity was delayed in the internal part of canopy. The fruit skin and wax layer were thicker in fruits from the internal canopy than in those from the external canopy. Therefore, our results indicate a need for improved light penetration in internal parts of the canopy and for split harvesting depending on maturity at different canopy positions.

• Journal of Korea Spatial Information System Society
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• v.8 no.2 s.17
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• pp.53-73
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• 2006

Recently, the need for Location-Based Services (LBS) has increased due to the development of mobile devices, such as PDAs, cellular phones and GPS. As a moving object database that stores and manages the positions of moving objects is the core technology of LBS, the scheme for maintaining the main memory DBMS to the server is necessary to store and process frequent reported positions of moving objects efficiently. However, previous works on a moving object database have studied mostly a disk based moving object index that is not guaranteed to work efficiently in the main memory DBMS because these indexes did not consider characteristics of the main memory. It is necessary to study the main memory index scheme for a moving object database. In this paper, we propose the main memory index scheme based on the R-tree for storing and processing positions of moving objects efficiently in the main memory DBMS. The proposed index scheme, which uses a growing node structure, prevents the splitting cost from increasing by delaying the node splitting when a node overflows. The proposed scheme also improves the search performance by using a MergeAndSplit policy for reducing overlaps between nodes and a LargeDomainNodeSplit policy for reducing a ratio of a domain size occupied by node's MBRs. Our experiments show that the proposed index scheme outperforms the existing index scheme on the maximum 30% for range queries.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.6
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• pp.391-398
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• 2003

Research was conducted to establish the leaf and petiole sap test to diagnose the nutritional status of tomato. The concentrations of $NO_3$, $PO_4$, K, Ca, Mg and $SO_4$ ions extracted from the leaves and petioles in the different positions in a plant were measured and compared with their corresponding inorganic contents in the leaves analyzed by the chemical method. The ionic concentrations in the leaf and petiole sap showed the different values depending on their positions in a plant. The leaves and petioles in the lower positions of a plant had higher concentrations of $NO_3$, Ca, Mg and $SO_4$ ions. In particular, there were greater changes of ionic concentrations and less increases in the leaf length and width from the 9th compound leaf down from the uppermost cluster. On the other hand, the leaflets in a compound leaf had the same ionic concentrations. Therefore, it appeared that the optimal sampling position of leaf and petiole for the sap test is the leaflets of the 9th compound leaf down from the uppermost cluster. A good correlation between the sap test and the chemical analysis of plant showed that the ionic concentrations in the leaf and petiole sap reflect the nutritional status of tomatoes.

• Imaging Science in Dentistry
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• v.44 no.1
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• pp.61-65
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• 2014

Purpose: This study was performed to evaluate the position of impacted mandibular third molars in different skeletal facial types among a group of Iranian patients. Materials and Methods: A total of 400 mandibular third molars in 200 subjects with different types of facial growth were radiographically investigated for their positions according to their types of facial growth on the basis of the ${\beta}$ angle. The subjects were divided into three groups (class I, II, and III) according to ANB angle, representing the anteroposterior relationship of the maxilla to the mandible. Meanwhile, the subjects were also divided into three groups (long, normal, and short face) according to the angle between the stella-nasion and mandibular plane (SNGoGn angle). ANOVA was used for statistical analysis. Results: The mean ${\beta}$ angle showed no significant difference among class I, II, and III malocclusions (df=2, F=0.669, p=0.513). The same results were also found in short, normal, and long faces (df=1.842, F=2, p=0.160). The mesioangular position was the most frequent one in almost all of the facial growth patterns. Distoangular and horizontal positions of impaction were not found in the subjects with class III and normal faces. In the long facial growth pattern, the frequency of vertical and distoangular positions were not different. Conclusion: In almost all of the skeletal facial types, the mesioangular impaction of the mandibular third molar was the most prevalent position, followed by the horizontal position. In addition, ${\beta}$ angle showed no significant difference in different types of facial growth.

• Journal of the Korean Society of Tobacco Science
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• v.6 no.2
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• pp.199-296
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• 1984

Symptoms of potassium deficiency were studied with flue-cured tobacco (N.C 2326) which had been applied with several levels of nitrogen and potassium fertilizer at 7, 10, and 13 Kg N/10a, and 15, 20, and $25KgK_2O/10a$, respectively. The distributions of T-N, $NH_4-N, \;NO_3-N$, and K contents in 18 leaves from the bottom to the top stalk position were investigated at 63 days after transplanting. The T-N content in the different stalk positions was increased from the bottom to the top ; however, vice versa in K content. As increasing the application levels, the increasing rate of the T-N content in the different leaf fractions were similar to those of rib and laminae. On the contrary, the rates of K content in the rib were higher then that of laminae and in the bottom than the top stalk position. Those indicated that the unbalance of nitrogen and potassium contents in the leaves came to maximum in the laminae of the top stalk position and was possibly affected by the application level of nitrogen rather than potassium. The T-N content in the laminae was higher than that of the rib. However the K and $NO_3$-N contents in the laminae were significantly lower than those of the rib. Therefore the $K^+$ uptake by tobacco was thought to be accompanied with $NO_3$- and transported smoothly up to the rib, but not from the rib to the laminae where assimilation materials were accumulated. Distribution of inorganic components in the different positions of vegetative organ were also investigated at 60 days after transplanting. The T-N and $P_2O_5$ contents were in order as; top > middle> bottom of the stalk and the stalk position, and laminae > vein > midrib of leaf fraction, however vice versa in K content of the stalk position and leaf fraction. In addition distributions of CaO and MgO contents in the each leaf fraction were resemble to that of the T-N content. On the contrary, the distributions of the CaO and MgO contents in the different stalk positions were similar to that of the K content.

• Journal of The Korean Society of Integrative Medicine
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• v.7 no.4
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• pp.33-41
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• 2019

Purpose : The muscle strength of iliopsoas (IL) was measured commonly in sitting position with hip and knee flexed 90°. However, there is no study to determine the muscle strength of IL in various test positions. Therefore, the purpose of this study was to compare the muscle strength of IL and muscle activity of rectus femoris (RF) according to test position and knee flexion angle. Methods : Twenty healthy subjects were participated for this study. The muscle strength of IL and muscle activity of RF were measured by hand-held dynamometer and surface electromyography during maximum voluntary isometric contraction (MVIC) of IL, respectively. The muscle strength of IL and muscle activity of RF was measured in 4 conditions as follows; 1) knee flexion angles 90 ° in supine, 2) 130 ° in supine position, 3) 90 ° in sitting, 4) 130 ° in sitting. Each condition were performed randomly by three repetitions. Results : The muscle strength of the IL was the main effect on the test position and knee flexion angle (p<.05), and the muscle activity of RF was the main effect only on the knee flexion angle (p<.05). There was also no interaction between the factors (p>.05). In supine position, the muscle strength of IL in knee flexion 130 ° was significantly less than that in knee flexion 90 ° (p<.0125). In knee flexion 90 °, the muscle strength of IL in supine position was significantly greater than that in sitting position (p<.0125). The muscle activity of RF in knee flexion 130 ° was significantly less than that in knee flexion 90 ° in supine and sitting positions (p<.0125). Conclusion : When the muscle strength of IL was measured in clinic and sports fields, the supine position with knee flexion 130 ° was recommended to prevent the muscle activation of RF and to maintain the trunk stability.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.4
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• pp.352-360
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• 2017

Objectives: This study aimed to determine the effects on musculoskeletal symptoms of both social demographic features and detailed characteristics of each task category of care workers who offer visiting home-help services. And to establish the measures that can reduce musculoskeletal symptoms among care workers. Methods: This study was conducted among 192 care workers from welfare centers C and K located in city P. After participants completed the task burden checklist regarding the scale of musculoskeletal symptoms and the details of their duties, the data collected were analyzed using the SPSS 21.0 program. Results: According to the degree of observable musculoskeletal symptoms in care workers, the highest figures were observed for back and shoulder pain. Based on the results of assessing the effect of detailed task category characteristics on musculoskeletal symptoms, "helping patients eat, helping patients move, helping patients bath, and changing body positions" were found to have an effect from the physical care category, "providing physical therapy assistance, treating bedsores" from the health care category, and "cleaning and doing laundry" from the facility management category. Conclusions: Due to the high proportion of patients requiring burdensome physical labor from care workers such as moving patients who have trouble doing so on their own, helping them change positions, and so on, it is highly likely that pain will occur in the low back, which carries most of the physical weight. So, education on human epidemiological positions that can reduce overload on areas prone to pain such as the low back and shoulders is essential. Proper equipment and personnel support must be provided for dangerous tasks. Further, multidimensional social support is required consistently.

• Journal of Animal Environmental Science
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• v.7 no.3
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• pp.155-164
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• 2001

Environmental factors such as $NH_3,\;H_2S,\;CO_2$, dust, temperature, and humidity in the animal house are a potential health hazard to humans and animals. Until now, most of measurement methods can only provide periodic results with low accuracy. A data acquisition system which can measure continuously and simultaneously $NH_3,\;H_2S,\;CO_2$, temperature, and humidity was developed and installed in two pig houses. Daily changes of environment for the pig-houses were investigated by the data acquisition system. In order to evaluate NH$_3$sensor, gas samples were obtained and NH$_3$concentrations were measured at nine positions; combinations of three positions(inlet, middle, and outlet) and three heights(0 cm, 40 cm, 150 cm). Ammonia concentration of 14.0 ~37.1 ppm for slurry pig-house is higher than that of 8.4~29.7 ppm for scraper pig-house, and there were no statistical differences among the positions. However, the concentration of $NH_3$at 150 cm was higher than thats of 0 cm and 40 cm.