• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.2
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• pp.58-76
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• 2019

As the number of reported injuries has tended to increase over time, large hospitalization expenditure from excessive medical treatments and hospitalization, and insurance frauds associated with moral hazard in minor collisions have caused a global societal problem. Many occupants of rear-ended vehicles involved in rear-end collisions complain of whiplash injury, which is also known as neck injury, without any anatomical and radiological evidence. With only clinical symptoms, stating that a whiplash injury is a type of injury defined by the Abbreviated Injury Scale would be difficult. Therefore, this study focuses on minor rear-end collisions, where the rear-ender vehicle collides with the rear-ended vehicle at rest. The mathematics dynamic model is employed to simulate a total of 100 rear-end collision scenarios based on various weights and collision speeds and identify how the weights and speeds of both vehicles influence the risk of whiplash injury in occupants involved in minor rear-end collisions. The possibility of an injury is very high when the same-weight vehicles are involved in accidents at collision speeds of 15 km/h or higher. The possibilities are 36% and 84% with collision speeds of 15 km/h and 20 km/h, respectively, if weights are disregarded.

• Progress in Medical Physics
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• v.12 no.1
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• pp.41-50
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• 2001

The quantification analysis of renal scintigraphy is strongly affected by the location, shape and size of region of interest(ROI). When ROIs are drawn manually, these ROIs are not reproducible due to the operators' subjective point of view, and may lead to inconsistent results even if the same data were analyzed. In this study, the effect of the ROI variation on the analysis of renal scintigraphy when the ROIs are drawn manually was investigated, and in order to obtain more consistent results, methods for automated ROI definition were developed and the results from the application of the developed methods were analyzed. Relative renal function, glomerular filtration rate and mean transit time were selected as clinical parameters for the analysis of the effect of ROI and the analysis tools were designed with the programming language of IDL5.2. To obtain renal scintigraphy, $^{99m}$Tc-DTPA was injected to the 11 adults of normal condition and to study the inter-operator variability, 9 researchers executed the analyses. The calculation of threshold using the gradient value of pixels and border tracing technique were used to define renal ROI and then the background ROI and aorta ROI were defined automatically considering anatomical information and pixel value. The automatic methods to define renal ROI were classified to 4 groups according to the exclusion of operator's subjectiveness. These automatic methods reduced the inter-operator variability remarkably in comparison with manual method and proved the effective tool to obtain reasonable and consistent results in analyzing the renal scintigraphy quantitatively.

• Progress in Medical Physics
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• v.14 no.4
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• pp.211-217
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• 2003

The Principal component analysis (PCA) is a well-known data analysis method that is useful in linear feature extraction and data compression. The PCA is a linear transformation that applies an orthogonal rotation to the original data, so as to maximize the retained variance. PCA is a classical technique for obtaining an optimal overall mapping of linearly dependent patterns of correlation between variables (e.g. neurons). PCA provides, in the mean-squared error sense, an optimal linear mapping of the signals which are spread across a group of variables. These signals are concentrated into the first few components, while the noise, i.e. variance which is uncorrelated across variables, is sequestered in the remaining components. PCA has been used extensively to resolve temporal patterns in neurophysiological recordings. Because the retinal signal is stochastic process, PCA can be used to identify the retinal spikes. With excised rabbit eye, retina was isolated. A piece of retina was attached with the ganglion cell side to the surface of the microelectrode array (MEA). The MEA consisted of glass plate with 60 substrate integrated and insulated golden connection lanes terminating in an 8${\times}$8 array (spacing 200 $\mu$m, electrode diameter 30 $\mu$m) in the center of the plate. The MEA 60 system was used for the recording of retinal ganglion cell activity. The action potentials of each channel were sorted by off­line analysis tool. Spikes were detected with a threshold criterion and sorted according to their principal component composition. The first (PC1) and second principal component values (PC2) were calculated using all the waveforms of the each channel and all n time points in the waveform, where several clusters could be separated clearly in two dimension. We verified that PCA-based waveform detection was effective as an initial approach for spike sorting method.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.2 no.1
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• pp.30-39
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• 1999

Purpose: Anorectal manometry is a way of investigation for ano-rectal sphincters. In this paper we evaluated the usefulness of anorectal manometry in constipation patients and compared the anal spnincter function in control, constipation and encopresis patients Methods: We analysed the data of anorectal function studies in normal children (control, n=11), children with constipation (constipation group, n=20) and children with encopresis (encopresis group, n=16). Results: The specific manometric parameters in normal children were like as follows; external anal sphinter pressure $21.0{\pm}8.00$ mmHg, internal anal sphicter pressure $30.0{\pm}14.57$ mmHg, conscious rectal sensitivity threshold $11.4{\pm}4.52$ mmHg. The above results were not different from that of previous studies except conscious rectal sensitivity threshold, which was slightly lower than that of others. Internal and external anal sphincter pressure were elevated significanlty in constipation and encopresis groups than in control, which results was the same in conscious rectal sensitivity threshold. But the values of rectoanal inhibitory threshold and percent relaxation of rectoanal inhibitory reflex were not different among control group, constipation group and encopresis group. External sphincter activity was increased during the act of bearing down for defecation in none of the child in control group, in 6 of 17 children in constipation group and 5 of 12 children in encopresis group. Conclusion: With the results of above we could say that complete history taking and physical examination are important in diagnosis of constipation, and we could say also that the anorectal manometry was a valuable tool to understand the physiology of normal defecation and the pathophysiology of constipation and encopresis.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.3
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• pp.307-316
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• 2003

Fish assemblage structure in a sheltered shallow water in the Southern Coast of Korea was examined monthly. Sampling was conducted in Doam Bay using a beam trawl between March 2001 and February 2001. A total of 53 fish species from 33 families were caught. Pinkgray goby (Chaeturichthys hexanema), ponyfish (Leiognathus nuchalis) and yellowfin goby (Acanthogobius favimanus) were the most frequent species, comprised 67.4％ of the total numbers captured. Snailfish (Liparis tanakai), yellowfin goby (Acanthogobius flavimanus) and pinkgray goby (Chaeturichthys hexanema) represented 50.8％ of the total biomass. While total abundance (number of individuals) and biomass were high in autumn and winter, species richness (number of species) and diversity were high in spring. Cluster analysis, based on monthly abundance data of the 14 most frequent species, showed that the species were separated into three different groups. Group A composed of pinkgray goby, yellowfin goby, robust tonguefish (Cynoglossus robustus) and scaly hairfin anchovy (Setipinna taty), which were year-round residents, and devil flathead (Onigocia spinosa), Red dragonet (Repomucenus lunatus) and ponyfish, which were abundant in autumn, group B surmullet (Upeneus japonicus), hairtail (Trichiurus lepturus) and gaff-topsail goby (Cryptocentrus filifer), which were abundant in summer, and group C grassfish (Liparis tanakai), spotted velvefish (Erisphex pottii), chameleon goby (Tridentiger trigonocephalus) and Richardson dragonet (Repomucenus richardsonii), which were abundant in winter and spring. A seasonal homogeneity of fish assemblage indicates that overall fish assemblage in Dom Bay is largely controlled by year-round residents.

• Journal of Korea Water Resources Association
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• v.38 no.10 s.159
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• pp.841-849
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• 2005

Two-phase flows, e.g. sediment-laden flow and bubbly flow, have two different flow profiles; flow velocity and sediment velocity. To measure velocity distributions of two-phase flows, it is necessary to use sophisticated instruments which can separate velocity profiles of two-phases. For bubbly flows, PIV (Particle Image Velocimetry) or PTV (Particle Tracking Velocimetry) has given fairly good velocity profiles of two-phases. However, for sediment-laden flows, the applications of PIV or PTV has not been so successful, because the sediment particles introduced to the flow kept the images from being analyzed. A new algorithm, which consists of several image analysis methods, is proposed to analyze sediment-laden flows. For detection algorithm, threshold method, edge detection method, and thinning method are adapted, and for finding matching pair PIV and PTV routines are combined. The proposed method can (1) detect sediment particles with irregular boundaries, (2) remove reflected images and scattered images, and (3) discriminate tracer particles from reflected images of sediment particles.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.3
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• pp.249-255
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• 2017

The finger vein recognition technology is a method to acquire a finger vein image by illuminating infrared light to the finger and to authenticate a person through processes such as feature extraction and matching. In order to recognize a finger vein, a 2D mask-based two-dimensional convolution method can be used to detect a finger edge but it takes too much computation time when it is applied to a low cost micro-processor or micro-controller. To solve this problem and improve the recognition rate, this study proposed an extraction method for the region of interest based on virtual core points and moving average filtering based on the threshold and absolute value of difference between pixels without using 2D convolution and 2D masks. To evaluate the performance of the proposed method, 600 finger vein images were used to compare the edge extraction speed and accuracy of ROI extraction between the proposed method and existing methods. The comparison result showed that a processing speed of the proposed method was at least twice faster than those of the existing methods and the accuracy of ROI extraction was 6% higher than those of the existing methods. From the results, the proposed method is expected to have high processing speed and high recognition rate when it is applied to inexpensive microprocessors.

• The Journal of the Korea Contents Association
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• v.7 no.12
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• pp.139-144
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• 2007

Radiotherapy which is the most effective for orbit lymphoma has been used increasingly due to the increase of orbit or ocular adnexal tumor patients. Curative effects and convalescence have been being more satisfied thanks to remarkable development of cancer chemotherapy and medical treatments, but side effects such as cataract, dry eye and retinopathy still break out. Thus, in this study, a Lens Shielding Device (LSD hereafter) was designed to prevent occurring of cataract due to radiation therapy for orbit lymphoma and its efficacy through dosimetry were evaluated. And in this paper, its manufacturing process was also explained. LSD is composed of a cover body covering the lens and a side fixing part supporting the cover body. To measure radiation, the patient therapy conditions were simulated and the measurement of the radiation was conducted with Thermo Luminescence Detector (TLD) and Markus chamber. The average TLD value was 5.7% and the TLD value and Markus chamber value were acquired as 4.2% and 5.1% respectively at 6 mm depth where zero lens center was located. Only 1.5Gy ($300Gy{\times}\;5%$) or 5% of total 30Gy with 9 MeV electron beam is estimated to affect on patient's lens. That is smaller dose than the threshold value of cataract (2GY) or the value (5Gy) that was reported to cause cataract in clinical conditions. Thus, these findings suggest that LSD be very useful for prevention of cataract during radiotherapy for malignant lymphoma of orbit and ocular adnexa. Furthermore, it might be possible to reduce patient's discomfort caused by alien substances and to make it easier to fix the device with customized manufacturing manners.

• Journal of Preventive Medicine and Public Health
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• v.30 no.4 s.59
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• pp.779-790
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• 1997

The Association between myofascial pain syndrome and some tests was assessed in a cross-sectional study of 904 female telephone operators using video display terminals(VDTs). 105 cases were diagnosed as Myofascial pain syndrome with symptom questionnaire, laboratory examination and physician's physical examination and 550 controls were defined to show only musculoskeletal symptoms using NIOSH symptom criteria. Data on demographics, musculoskeletal symptom and visual analogue scale(VAS) were obtained by questionnaire. Anthropometric measurements, pressure pain threshold, Grip & Pinch strength and laboratory test were conducted. No significant difference between case and control at comparing of demographics, occupational history and body measurements were observed. But, Grip strength, pressure pain threshold and VAS showed the statistical difference between case and controt. Age, pressure pain threshold of Rt. Upper trapezius and VAS were associated with myofascial pain syndrome in multivariate logistic regression analysis. This results suggest that, to diagnose of myofascial pain syndrome, the consideration of the objective aspects among patients' subjective symptom complaints through the VAS and pressure pain threshold is required.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.3
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• pp.174-182
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• 2006

This study was to clarify the effects of forest stand changes on hydrological components of evapotranspiration and discharge. The forest-hydrological experimental stations in Gwangneung and Yangju, Gyeonggido near metropolitan Seoul have been operated by the Korea Forest Research Institute since 1979 to clarify the effects of forest types and practices on the water resources and nutrient cycling and soil loss. The hydrological regime of the forested catchments may change as forests develop. The ranges of change may be different depending on forest types. Evapotranspiration can be estimated to 679mm, 580mm and 368mm in planted young coniferous (PYC), natural old-growth deciduous (NOD) and rehabilitated young mixed (RYM), respectively. The slope of the discharge-duration curve shows the capacity of discharge control in a specific catchment. The slope tended to be steeper in RYM than NOD, the better forest condition. The slope in RYM became more gentle as the forest stand developed. Forests can modulate peak flows through interception, evapotranspiration and soil storage opportunity. PYC and RYM showed 100 and 50mm of threshold rainfall for modulating peak flows, respectively. The deciduous forest did not represent sudden changes of peak flow rates to rainfall, even 200 mm rainfall Forest development in PYC may play an important role in modulation of peak flows because peak flow rates reduced after 10 years.