• The KIPS Transactions:PartA
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• v.11A no.7 s.91
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• pp.555-562
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• 2004

Both global volume reduction and local shape changes of hippocampus within the brain indicate their abnormal neurological states. Hippocampal shape analysis consists of two main steps. First, construct a hippocampal shape representation model ; second, compute a shape similarity from this representation. This paper proposes a novel method for the analysis of hippocampal shape using integrated Octree-based representation, containing meshes, voxels, and skeletons. First of all, we create multi-level meshes by applying the Marching Cube algorithm to the hippocampal region segmented from MR images. This model is converted to intermediate binary voxel representation. And we extract the 3D skeleton from these voxels using the slice-based skeletonization method. Then, in order to acquire multiresolutional shape representation, we store hierarchically the meshes, voxels, skeletons comprised in nodes of the Octree, and we extract the sample meshes using the ray-tracing based mesh sampling technique. Finally, as a similarity measure between the shapes, we compute $L_2$ Norm and Hausdorff distance for each sam-pled mesh pair by shooting the rays fired from the extracted skeleton. As we use a mouse picking interface for analyzing a local shape inter-actively, we provide an interaction and multiresolution based analysis for the local shape changes. In this paper, our experiment shows that our approach is robust to the rotation and the scale, especially effective to discriminate the changes between local shapes of hippocampus and more-over to increase the speed of analysis without degrading accuracy by using a hierarchical level-of-detail approach.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.1
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• pp.188-198
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• 2005

The Goldschmidt iterative algorithm for finding a floating point square root calculated it by performing a fixed number of multiplications. In this paper, a variable latency Goldschmidt's square root algorithm is proposed, that performs multiplications a variable number of times until the error becomes smaller than a given value. To find the square root of a floating point number F, the algorithm repeats the following operations: $R_i=\frac{3-e_r-X_i}{2},\;X_{i+1}=X_i{\times}R^2_i,\;Y_{i+1}=Y_i{\times}R_i,\;i{\in}\{{0,1,2,{\ldots},n-1} }}'$with the initial value is $'\;X_0=Y_0=T^2{\times}F,\;T=\frac{1}{\sqrt {F}}+e_t\;'$. The bits to the right of p fractional bits in intermediate multiplication results are truncated, and this truncation error is less than $'e_r=2^{-p}'$. The value of p is 28 for the single precision floating point, and 58 for the doubel precision floating point. Let $'X_i=1{\pm}e_i'$, there is $'\;X_{i+1}=1-e_{i+1},\;where\;'\;e_{i+1}<\frac{3e^2_i}{4}{\mp}\frac{e^3_i}{4}+4e_{r}'$. If '|X_i-1|<2^{\frac{-p+2}{2}}\;'$ is true, $'\;e_{i+1}<8e_r\;'$ is less than the smallest number which is representable by floating point number. So, $\sqrt{F}$ is approximate to $'\;\frac{Y_{i+1}}{T}\;'$. Since the number of multiplications performed by the proposed algorithm is dependent on the input values, the average number of multiplications per an operation is derived from many reciprocal square root tables ($T=\frac{1}{\sqrt{F}}+e_i$) with varying sizes. The superiority of this algorithm is proved by comparing this average number with the fixed number of multiplications of the conventional algorithm. Since the proposed algorithm only performs the multiplications until the error gets smaller than a given value, it can be used to improve the performance of a square root unit. Also, it can be used to construct optimized approximate reciprocal square root tables. The results of this paper can be applied to many areas that utilize floating point numbers, such as digital signal processing, computer graphics, multimedia, scientific computing, etc.

• The Korean Journal of Mycology
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• v.15 no.1
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• pp.48-69
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• 1987

To understand host ranges and host specificity of ectomycorrhizal fungi and fungus specificity of host tree species, higher fungi from pure forest stands of following twelve tree species were collected for six years from 1981 to 1986: Pinus densiflora, P. rigida, P. koraiensis, Picea koraiensis, Larix leptolepis, Abies holophylla, Populus $alba{\times}glandulosa$, Castanea crenata, Quercus aliena, Q. acutissima, Q. mongolica, and Betula platyphylla. A total of 196 ectomycorrhizal species with 8 varieties in 48 genera were identified. Thirty-one species with one variety belonged to Russula, 22 species with 5 varieties to Amanita, 18 species with one variety to Lactarius. Fungi belonging to above three gepera, Laccaria, and Cantharellus had a relatively wide host range. Laccaria laccata was collected under all the 12 tree species, Amanita vaginata group under 11 tree species, Laccaria amethystina and Russula foetens under 10 tree species, Lactarius gerardii and Russula sororia under 9 tree species, and Amanita agglutinata, Cantharellus cibarius, Russula bella, and R. virescens under 8 tree species. Above 10 fungal species may be classified to have a wide host range. Following fungi were collected under 4 to 5 tree species of both conifers and broad-leaved trees: Amanita citrina, Boletus bicolor, B. erythropus, Lactarius piperatus, L. subzonar­ius, and Russula pseudodelica. Above fungi may be classified to have an intermediate host range. Chroogomphus, Gomphidius, Rhizopogon, and Suillus were collected only under Pinaceae and may be classified to have a narrow host range. Particularly Suillus grevillei was collected only under Larix leptolepis, and appeared to have high host specificity. A total of 83 ectomycorrhizal species were collected under Abies holophylla, 66 species under Pinus densiflora, 50 species under Pinus rigida, 49 species under Pinus koraiensis, 46 species under Quercus aliena, and 23 fungal species under Larix leptolepis. Particularly, Larix leptolepis was associated with different fungal flora, with fewer species of Amanita, Lactarius and Russula, and more species of Laccaria. Most host tree species surveyerl in the present study appeared to have low fungus specificity for ectomycorrhizal formation.

• Clinical and Experimental Pediatrics
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• v.52 no.6
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• pp.689-695
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• 2009

Purpose : To examine the effect of bosentan, a dual endothelin receptor (ER) antagonist, on the development of monocrotaline (MCT)-induced pulmonary hypertension in rats by especially focusing on the pulmonary vascular morphology changes. Methods : Sprague-Dawley rats were treated as follows: controls received a subcutaneous saline injection, MCT-treated rats received a subcutaneous MCT injection, and bosentan-treated rats received a MCT injection followed by treatment with bosentan (20 mg/kg/day). To assess the effects of ER blockade on the time course, the animals were exsanguinated, and their hearts and lungs were dissected after 7, 14, or 28 days. Results : The mean body weights of the MCT- and bosentan-treated rats were significantly lower than that of the control rats on days 7, 14, and 28. Bosentan administration significantly inhibited the progression of right ventricular hypertrophy on day 28 (right ventricle/[left ventricle＋septum]: $0.71{\pm}0.10$ in MCT-treated rats vs. $0.49{\pm}0.09$ in bosentan-treated rats; P<0.05). Quantitative analysis of peripheral pulmonary arteries revealed that the increase in medial wall thickness after MCT injection was significantly attenuated in the bosentan-treated rats on day 28 ($49.96{\pm}10.06%$ in MCT-treated rats vs. $47.09{\pm}10.48%$ in bosentan-treated rats; P<0.05). In addition, the increase in the number of intra-acinar muscular arteries after MCT injection was reduced by bosentan on days 14 and 28. Conclusion : Bosentan administration in intermediate doses exerts inhibitory effects on lung vascular hypertrophy and right ventricular hypertrophy during the development of MCT-induced pulmonary hypertension in rats.

• Investigative Magnetic Resonance Imaging
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• v.10 no.2
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• pp.98-107
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• 2006

Magnetization Transfer (MT) imaging generates contrast dependent on the phenomenon of magnetization exchange between free water proton and restricted proton in macromolecules. In biological materials in knee, MT or cross-relaxation is commonly modeled using two spin pools identified by their different T2 relaxation times. Two models for cross-relaxation emphasize the role of proton chemical exchange between protons of water and exchangeable protons on macromolecules, as well as through dipole-dipole interaction between the water and macromolecule protons. The most essential tool in medical image manipulation is the ability to adjust the contrast and intensity. Thus, it is desirable to adjust the contrast and intensity of an image interactively in the real time. The proton density (PD) and T2-weighted SE MR images allow the depiction of knee structures and can demonstrate defects and gross morphologic changes. The PD- and T2-weighted images also show the cartilage internal pathology due to the more intermediate signal of the knee joint in these sequences. Suppression of fat extends the dynamic range of tissue contrast, removes chemical shift artifacts, and decreases motion-related ghost artifacts. Like fat saturation, phase sensitive methods are also based on the difference in precession frequencies of water and fat. In this study, phase sensitive methods look at the phase difference that is accumulated in time as a result of Larmor frequency differences rather than using this difference directly. Although how MT work was given with clinical evidence that leads to quantitative model for MT in tissues, the mathematical formalism used to describe the MT effect applies to explaining to evaluate knee disorder, such as anterior cruciate ligament (ACL) tear and meniscal tear. Calculation of the effect of the effect of the MT saturation is given in the magnetization transfer ratio (MTR) which is a quantitative measure of the relative decrease in signal intensity due to the MT pulse.

• Journal of Preventive Medicine and Public Health
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• v.28 no.2 s.50
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• pp.334-346
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• 1995

To investigate the factors influencing workers' perception and attitude toward special periodic health screening test for workers, a survey with self-administered questionnaires was performed on 779 workers who had special periodic health screening test from September 1 to October 15, 1994. A study model was developed by modifying the health belief model. The end and intermediate response variables of the model were the voluntary participation and necessity perception on the special screening for workers. The result of analysis was consistent with the study model. Rates for the necessity perception and voluntary participation on the special screening for workers were 77.2%, 79.2%, respectively. Factors influencing on the voluntary participation were necessity perception, benefit of special screening for workers, and cue to action. And on the necessity perception were susceptibility and severity to occupational disease, knowledge to special screening for workers, and support of company. General and occupational characteristics influencing on the susceptibility and severity to occupational disease were sex, age, educational level, work duration, and health education. On the knowledge to special screening for workers were age, educational level, work duration, and locus-of-control. On the benefit of special screening for workers were age, locus-of-control, pride on health, and health education. Therefore, to increase the voluntary participation and necessity perception on the special periodic health screening for workers, 1) if a worker is judged as occupational disease, the judgment should be widely known in his workplace, 2) the screening result forms should be directly sent to the workers themselves, 3) for the positivity of employers, the campaign and education program subjected to them should be planned, 4) health education should give the first consideration to the younger, lower educational level, and newly employed women, and its frequency should be increased and it should be more frequently dealt with occupation-related subjects, and 5) the employers should have a careful concern in not being disadvantageous to workers due to result of screening.

• Parasites, Hosts and Diseases
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• v.23 no.1
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• pp.123-139
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• 1985

The present survey was undertaken to observe the geographical distibution of matacercaria among the sweetfish, Plecoglossus altivelis, the most important second intermediate host of Metagonimus yokegawai, which were collected during the period from 1983 to 1984 in south-eastern coastal areas of Korea. The results obtained were summarized as follow: 1. A total of 668 sweetfish collected from 70 chins (=streams) in the above coastal arcus was examined for the metacercariae, and 432 (64.7%) among them were infected with metacercariae of M. yokogawai. The mean number of metacercariae in a fish was in the range from 0 to 29,604 and the mean number of the metacercariae in a fish was 640.3. 2. It was observed that the mean infection rate showed 46.45 in Gangweon-Do (=province) . The infection rates varied from stream to stress showing 100% in Namdae stream(Gangnun-city) , Obsib stream (Samchok-gun) and Dongmak, 95.0% in Hosan stream, 90.0% in Gungchin stream, and Namdae stream (Yangyang-fp) ,80.0% in Hwasang stream,50.0% in Daebong stream,45.0% in Yonghwa stream, 30.0% in sangchsn stream and Sachsn stream, 20.0% in Munam stream and Okgyoe stream, 15.0% in Imweon stream, 10.0% in Namchsn stream. And no metacercarial infections in their fish host were found in the areas of Mulchi stream, Sangun stream, Gosamun stream, Jonchon stream and Gagok stream. 3. It was observed that the mean infection rate showed 50.9% in Kyangsangbuk-Do (=province). The infection rates also varied from stream to stream showing 100% in Songchon stream, Osib stream (Yongdok-gun) and Daejong stream,60.0% in Pyanghae stream and Gunmu stream,50.0% in Buhwung stream and stream, 25.0% in Nagok stream, 20.0% in Oangbi stream, 10.0% in Namhodong stream. And no metacercarial infections in their fish host were found in the areas of Namdae stream (Uljinup) and Chaksan stream. 4. It was observed that the mean infection rate showed 67.6% in Kyangsangnam-Do(=province). The infection rates varied from stream to stream showing 100% in Taehwa river, Hwiya river, Inchfn stream, Miryang river, Nam river, Hwagae stream, Koha stream, Sosang stream, and Tongchon stream,90.9% in Yancho stream,90.0% in Hoihwa stream,80.0% in Chindong stream, 66. YoA in Chingyo stream, 40.0% in Hoyam river. And no metacercarial infections in their fish host were found in the areas of Chinjon stream, Sanchan stream and Jukch6n stream. 5. It was observed that the mean infection rate showed 94.6"A in 0h511anam-Do(=province). The infection rates varied from stream to stream showing 100% in DongchEn stream, Isachon stream, Somjin river(GoksEng-gun) , Ssmjin river(Kurye-gun) , S6si stream, Gokchsn stream, Kohung stream, Kwansan stream, Youi stream, stream, Unj6n stream and Apnae stream, 92.3% in Tamjin river, 90.9% in Okkok stream, 84.6% in Songgen stream. And no metacercarial infections in their fish host were found in the area of Ypmgpl stream. 6. On the other hand, the infection rate showed 100% in Inchsn river of Chollabuk Do (=province) (=province) and Kangsn stream of Cheju-Do(=province) .

• Parasites, Hosts and Diseases
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• v.23 no.1
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• pp.87-94
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• 1985

The seasonal variations of the rate and intensity of metacercarial infection of C. sinensis in P. parva were observed. The fish were collected at Sun-Am River which located in Kim-Hae City, Kyong-Sang Nam Do (=Province), Korea, from March 1983, to February 1984 every month. A total of 788 fish was examined. The number of metacercariae in each fish was individually counted after the individual digestion by artificial gastric juice. The results were as follows: 1. During one year, 513 (65.1%) out of 788 fish were infected with metacercariae. In May, June, July and September, the infection rates ranged from 82.0% to 98.6% whereas the rates was relatively low in March, April, November and February ranging from 11.4% to 64.7%. 2. The intensity of infection was similar with those of infection rates. The mean intensity per infected fish was 103.0 and standard deviation was 118.9 throughout one year. The highest mean intensity was in June (294.8) and the lowest in November (11.1). 3. The observed frequency of fish with certain intensities of metacercariae were fitted to theoretical equations derived from negative binomial distribution in March, April, November and February (p>0.05). Meanwhile, the equation of lognormal distribution were fitted with the observed frequencies in May, June, July and September (p>0.05, p>O. 75). The variance/mean ratio varied by month. The value was the highest in July (814.3) and the lowest in November (158.8). Unlike our hypothesis, the metacercarial density of Clonorchis sinensis in its the most favorable fish host, Pseudorasbora parva showed considerable seasonal variations in the hyperendemic area. The possible factors were discussed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.4
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• pp.305-312
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• 1992

This experiment was carried out to investigate seed set, variation in chromosome number, and agronomic characteristics of the progeny in the cross between hexaploid triticale variety, Sinkihomil(P$_1$) and tetraploid rye variety, Dooroohomil(P$_2$). Seed set rate obtained was 30.5% in the cross of Sinkihomil with Dooroohomil, whereas 3.26% in reciprocal cross using Dooroohomil as female. Alsoseed set was 8.75% in F$_1$/P$_1$, 7.20% in F$_1$/P$_2$, and 1.53% in F$_2$(=F$_1$ /F$_1$, respectively. Germination rate of crossed seed was 37% in cross of P$_1$ with P$_2$, 39.0% in F$_1$/P$_1$(BC$_1$), 50% in F$_1$/P$_2$(BC$_2$) and 43.0% in F$_1$/F$_1$(F$_2$), and 1,000 grain wight was 20.7g in the cross of P$_1$ with P$_2$, which have 41.9g and 47.7g, respectively, 24.5g in F$_1$/P$_1$, 23.6g in F$_1$/P$_2$, and 24.5g in F$_1$/F$_1$, respectively. In pollen fertility of F$_1$ plant, 69.8% turned out to be abnormal or sterile pollen grains, whereas 30.2% was fertile or normal. In meiosis of pollen mother cell of F$_1$ plant, 13.5 univalents, 8.89 bivalent and 1.24 trivalent were appeared. Somatic chromosome number of 35 in F$_1$, both 32 to 33 and 35 to 36 in F$_2$, 35 to 39 in BC$_1$ and 28 to 36 in BC$_2$ which mean producing female gamate was 14 to 18 chromosome in PMC of F$_1$ plant. Rate of fertile plant turned out to be 100% in F$_1$, 4.5% in F$_2$, 42.9% in BC$_1$, and 50.0% in BC$_2$, respectively. Number of seed set per spike appeared to be 1.17 in F$_1$ plant, 13.3 in F$_2$, 2.36 in BC$_1$, and 3.75 in BC$_2$, respectively. Days to heading of F$_1$ was intermediate, but F$_2$ was later than both parents. Plant height of F$_1$ , BC$_1$ ,and BC$_2$ was shorter than both parent, but F$_2$, longer than both parents.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.5
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• pp.517-523
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• 2008

The degradation mechanism of Triclosan(TCS), which is a potent broad-spectrum antimicrobial agent and has been considered as an emerging pollutant, was investigated in the Fenton and the hybrid reaction with Fe$^{2+}$ and UV-C. The results show that the Fe$^{2+}$ is oxidized to 30% by $H_2O_2$, 28% by UV-C, and 15% by UV-A for 10 min. The degradation rate of TCS for beginning time(10 min) was higher in UV-C only reaction than that in hybrid reaction, which of the order was inverted according to the lapse of reaction time. The effect of methanol was the greatest in Fenton reaction, in which the degradation rate of TCS decreased from 90% to 5% by the addition of methanol. Chloride, ionic intermediate, was produced to 77% for 150 min of hybrid reaction(Fe$^{2+}$ + UV-C), which was the greatest. In case with methanol, the generation rate of chloride for 15 min was ignorable in all reactions($\leq$2%) but the hybrid reaction with Fe$^{2+}$ and UV-C(12%). Additionally, the removal rate of TOC in each reaction was estimated as the followed orders; Fe$^{2+}$ + UV-C > Fe$^{2+}$ + $H_2O_2$ > Fe$^{2+}$ + UV-A > UV-C > UV-A. However, the Fenton reaction was almost stopped after 90 min because the reaction between Fe$^{2+}$ and $H_2O_2$ cannot be kept on without adding the oxidant. The phenomena was not observed in the hybrid reaction. In view of generating chloride, the reductive degradation of TCS may be in the hybrid reaction with Fe$^{2+}$ and UV-C, which is favorable to mineralize halogenated organic compounds such as TCS. Consequently, the hybrid process with Fe$^{2+}$ and UV-C may be considered as the alternative treatment method for TCS.