• Journal of the Korean Academy of Child and Adolescent Psychiatry
• /
• v.16 no.2
• /
• pp.199-210
• /
• 2005

Objective : Attention deficit hyperactivity disorder(ADHD) affects $5-10\%$ of children in Korea, with more boys and girls being diagnosed. Despite seriousness of ADHD, little is known about its causes. From the current genetic epidemiologic studies, ADHD is known as a heritable disorder. Till now, however, there have been very few genetic studies about ADHD in Korea. The aim of the this study is to examine the association between dopamine transporter gone type 1 and ADHD using case-control design in Korean ADHD probands and normal controls. Materials and Method : Child Psychiatric Genetic research team in Seoul National University Hospital, Clinical Research Institute recruited the ADHD probands using clinical interview/observation, diverse rating scales, and neuropsychological tests. For eliminating phenocopy or ADHD, diagnosis of ADHD was based upon clinical data, psychometric data, and parent/teacher reports. Total 85 ADHD-probands were recruited as final study subjects and independent 100 normal adults participated in this study as control group. For all the ADHD probands, and controls, the 3'-UTR-VNTR polymorphism of DAT1 was analyzed. Based on the DAT1 allele and genotype informations, Chi-square test based on case-control design was performed. Results : As for genetic study, total of 85 probands and 100 controls were included for the genetic analysis. Four different alleles, 350bp (7repeat), 440bp (9repeat), 480bp (10repeat) and 520bp (11repeat) were found in DAT1 gene of study subjects. In case-control analysis, ADHD probands and parents have significantly more 9 repeat allele and 9/10 genotype. Also, The probands with 9repeat allele have more commission errors in ADS. Conclusion : The positive association between ADHD and DAT1 gene was replicated in this report like other previous results for caucasian children and Korean children with ADHD. There are ongoing studies on other candidate genes such as DRD4 and DRD5 and it would be required to explore the association of these candidate genes in Korean children with ADHD. These ongoing genetic research will contribute to the understanding of heterogenous genetic and environmental etiologies of ADHD phenotype, which will lead to the development of more comprehensive treatment and preventive interventions for ADHD.

• Journal of Intelligence and Information Systems
• /
• v.21 no.2
• /
• pp.1-18
• /
• 2015

Collaborative filtering(CF) algorithm has been popularly used for recommender systems in both academic and practical applications. A general CF system compares users based on how similar they are, and creates recommendation results with the items favored by other people with similar tastes. Thus, it is very important for CF to measure the similarities between users because the recommendation quality depends on it. In most cases, users' explicit numeric ratings of items(i.e. quantitative information) have only been used to calculate the similarities between users in CF. However, several studies indicated that qualitative information such as user's reviews on the items may contribute to measure these similarities more accurately. Considering that a lot of people are likely to share their honest opinion on the items they purchased recently due to the advent of the Web 2.0, user's reviews can be regarded as the informative source for identifying user's preference with accuracy. Under this background, this study proposes a new hybrid recommender system that combines with users' review mining. Our proposed system is based on conventional memory-based CF, but it is designed to use both user's numeric ratings and his/her text reviews on the items when calculating similarities between users. In specific, our system creates not only user-item rating matrix, but also user-item review term matrix. Then, it calculates rating similarity and review similarity from each matrix, and calculates the final user-to-user similarity based on these two similarities(i.e. rating and review similarities). As the methods for calculating review similarity between users, we proposed two alternatives - one is to use the frequency of the commonly used terms, and the other one is to use the sum of the importance weights of the commonly used terms in users' review. In the case of the importance weights of terms, we proposed the use of average TF-IDF(Term Frequency - Inverse Document Frequency) weights. To validate the applicability of the proposed system, we applied it to the implementation of a recommender system for smartphone applications (hereafter, app). At present, over a million apps are offered in each app stores operated by Google and Apple. Due to this information overload, users have difficulty in selecting proper apps that they really want. Furthermore, app store operators like Google and Apple have cumulated huge amount of users' reviews on apps until now. Thus, we chose smartphone app stores as the application domain of our system. In order to collect the experimental data set, we built and operated a Web-based data collection system for about two weeks. As a result, we could obtain 1,246 valid responses(ratings and reviews) from 78 users. The experimental system was implemented using Microsoft Visual Basic for Applications(VBA) and SAS Text Miner. And, to avoid distortion due to human intervention, we did not adopt any refining works by human during the user's review mining process. To examine the effectiveness of the proposed system, we compared its performance to the performance of conventional CF system. The performances of recommender systems were evaluated by using average MAE(mean absolute error). The experimental results showed that our proposed system(MAE = 0.7867 ~ 0.7881) slightly outperformed a conventional CF system(MAE = 0.7939). Also, they showed that the calculation of review similarity between users based on the TF-IDF weights(MAE = 0.7867) leaded to better recommendation accuracy than the calculation based on the frequency of the commonly used terms in reviews(MAE = 0.7881). The results from paired samples t-test presented that our proposed system with review similarity calculation using the frequency of the commonly used terms outperformed conventional CF system with 10% statistical significance level. Our study sheds a light on the application of users' review information for facilitating electronic commerce by recommending proper items to users.

• Journal of Korean Ophthalmic Optics Society
• /
• v.13 no.4
• /
• pp.65-73
• /
• 2008

Purpose: The purpose of this study is to investigate the effect of age in the response to long-term overnight orthokeratology (OK) lens wearing. Methods: Among volunteers, ninety-five healthy subjects who had no eye diseases and could wear OK contact lens at least for 8 hours every day were divided into three groups children, youngsters and young adults. Unaided logMAR visual acuity, refractive error, apical corneal radius, corneal asphericity and central corneal thickness were measured with different period; before and after one day, one week, two weeks, one month, three months and six months of OK lens wear. Paired student t-test, ANOVA analysis and Pearson correlation were used with a critical p value of 0.05 for statistical analysis. Results: All groups showed statistically significant (p<0.001) improvement in unaided visual acuity, a trend for flattening in the apical corneal radius, decrease in central corneal thickness and less prolate after OK lens wear. The child group showed significantly rapid change (p<0.001) in visual acuity, and apical corneal radius showed that they reached the targeted refractive change earlier compared with youngster and adult groups. The visual effect of OK lens was significantly related with the change in central corneal thickness after long-term OK lens wear, especially in child and youngster group, and central corneal thickness were highly correlated with the targeted refractive change. Conclusions: Visual acuity change is statistically correlated with the central corneal thickness change, which is highly correlated with targeted refractive change in the long-term orthokeratology and younger lens wearers showed a rapid response to OK lens wear, suggesting a reduced epithelial response with increasing age. The results found this study extends our understanding and development in the long-term orthokeratology.

• The Korean Journal of Nuclear Medicine
• /
• v.30 no.4
• /
• pp.476-483
• /
• 1996

Following radiation therapy for brain tumors, patients often have clinical deterioration due to either radiation necrosis or recurrent tumor progression in the treatment field. The distinction between these entities is important but difficult clinically or even with CT or MRI. T1-201 has been known to accumulate in various tumors and be useful to grade, predict prognosis or detect recurrence of glioma. The aim of this study was to evaluate the usefulness of T1-201 SPECT in the differentiation of recurrent tumor from radiation necrosis. Of 67 patients who did T1-201 brain SPECT imaging with clinically suspected recurrent tumor or radiation necrosis, 20 patients underwent histopathological examination and constituted the study population. T1-201 uptake indices on T1-201 brain SPECT imaging rrere calculated and correlated with histopathological diagnosis. Of 20 patients, 15 were histopathologically confirmed as recurrent original tumor or malignant transformation of benign tumor and 5 were diagnosed as radiation necrosis. On T1-201 SPECT, 18 of 20 had T1-201 index above 2.5 which was regarded as positive indicator for the presence of tumor. Seventeen cases showed concordance, which consisted of 15 true positive and 2 true negative. Discordant 3 cases were all false positive. There was no case of false negative. The sensitivity, specificity, positive and negative predictive value of T1-201 SPECT were 100%, 40%, 83% and 100%. In conclusion, T1-201 brain SPECT is a sensitive diagnostic test in the detection of recurrent tumor following radiation therapy and is useful in the differentiation of recurrent tumor from radiation necrosis. Relatively low specificity should be evaluated further in larger number of patients in consideration of sampling error and referral bias for pathologic examination.

• Explosives and Blasting
• /
• v.9 no.1
• /
• pp.3-13
• /
• 1991

The cautious blasting works had been used with emulsion explosion electric M/S delay caps. Drill depth was from 3m to 6m with Crawler Drill ${\phi}70mm$ on the calcalious sand stone (soft -modelate -semi hard Rock). The total numbers of test blast were 88. Scale distance were induced 15.52-60.32. It was applied to propagation Law in blasting vibration as follows. Propagtion Law in Blasting Vibration $V=K(\frac{D}{W^b})^n$ were V : Peak partical velocity(cm/sec) D : Distance between explosion and recording sites(m) W : Maximum charge per delay-period of eight milliseconds or more (kg) K : Ground transmission constant, empirically determind on the Rocks, Explosive and drilling pattern ets. b : Charge exponents n : Reduced exponents where the quantity $\frac{D}{W^b}$ is known as the scale distance. Above equation is worked by the U.S Bureau of Mines to determine peak particle velocity. The propagation Law can be catagorized in three groups. Cubic root Scaling charge per delay Square root Scaling of charge per delay Site-specific Scaling of charge Per delay Plots of peak particle velocity versus distoance were made on log-log coordinates. The data are grouped by test and P.P.V. The linear grouping of the data permits their representation by an equation of the form ; $V=K(\frac{D}{W^{\frac{1}{3}})^{-n}$ The value of K(41 or 124) and n(1.41 or 1.66) were determined for each set of data by the method of least squores. Statistical tests showed that a common slope, n, could be used for all data of a given components. Charge and reduction exponents carried out by multiple regressional analysis. It's divided into under loom over loom distance because the frequency is verified by the distance from blast site. Empirical equation of cautious blasting vibration is as follows. Over 30m ------- under l00m ${\cdots\cdots\cdots}{\;}41(D/sqrt[2]{W})^{-1.41}{\;}{\cdots\cdots\cdots\cdots\cdots}{\;}A$ Over 100m ${\cdots\cdots\cdots\cdots\cdots}{\;}121(D/sqrt[3]{W})^{-1.66}{\;}{\cdots\cdots\cdots\cdots\cdots}{\;}B$ where ; V is peak particle velocity In cm / sec D is distance in m and W, maximLlm charge weight per day in kg K value on the above equation has to be more specified for further understaring about the effect of explosives, Rock strength. And Drilling pattern on the vibration levels, it is necessary to carry out more tests.

• Korean Journal of Clinical Laboratory Science
• /
• v.49 no.4
• /
• pp.407-412
• /
• 2017

The aim of this study was to shorten the time required for subculture and bacterial identification and obtain a simple and rapid identification method for new test methods for bloodstream infections. The following results were obtained using a mass spectrometer. In Vitek 2, 208 (81.8%) cases were well-identified and 45 isolates were not identified in blood cultures. Among 208 cases, 146 (57.5%) were Gram positive bacteria and 108 (42.5%) were Gram negative bacteria. In total, 233 were identified to the species level and 21 were identified to the genus level. The identification error was found to be Propionibacterium acnes as Clostridium bifermentans. The accuracy of Enterobacteriaceae, glucose non-fermentative bacilli (GNFB), and staphylococci were 81/83 (97.6%), 12/15 (80.0%), and 72/85 (84.7%), respectively. The concordance rate of Vitek 2 and Vitek MS by the direct method was 81.8% and 45 isolates were not identified. Most of the unidentified bacteria were Gram positive bacteria (N=37). The Gram positive bacteria were streptococci (14), coagulase-negative staphylococci (CNS) (11), enterococci (3), Staphylococcus aureus (2), Micrococcus spp. (2), Bacillus spp. (2) and Actinomyces odontolyticus, Finegoldia magna, and Peptostreptococcus spp. The results reporting time was reduced to 24~72 hours compared to the conventional method. The rate of identification of the aerobic and anaerobic cultures was similar, but the use of an anaerobic culture did not require a dissolution process, which could shorten the sample preparation time. These results suggest that the method of direct identification in blood cultures is very useful for the treatment of patients. In further studies, it might be necessary to further improve the method for identifying streptococci and CNS, which were lacking in accuracy in this study.

• Korean Journal of Remote Sensing
• /
• v.31 no.5
• /
• pp.449-459
• /
• 2015

The conventional National Forest Inventory(NFI)-based forest carbon stock estimation method is suitable for national-scale estimation, but is not for regional-scale estimation due to the lack of NFI plots. In this study, for the purpose of regional-scale carbon stock estimation, we created grid-based forest carbon stock maps using spatial ancillary data and two types of up-scaling methods. Chungnam province was chosen to represent the study area and for which the $5^{th}$ NFI (2006~2009) data was collected. The first method (method 1) selects forest type map as ancillary data and uses regression model for forest carbon stock estimation, whereas the second method (method 2) uses satellite imagery and k-Nearest Neighbor(k-NN) algorithm. Additionally, in order to consider uncertainty effects, the final AGB carbon stock maps were generated by performing 200 iterative processes with Monte Carlo simulation. As a result, compared to the NFI-based estimation(21,136,911 tonC), the total carbon stock was over-estimated by method 1(22,948,151 tonC), but was under-estimated by method 2(19,750,315 tonC). In the paired T-test with 186 independent data, the average carbon stock estimation by the NFI-based method was statistically different from method2(p<0.01), but was not different from method1(p>0.01). In particular, by means of Monte Carlo simulation, it was found that the smoothing effect of k-NN algorithm and mis-registration error between NFI plots and satellite image can lead to large uncertainty in carbon stock estimation. Although method 1 was found suitable for carbon stock estimation of forest stands that feature heterogeneous trees in Korea, satellite-based method is still in demand to provide periodic estimates of un-investigated, large forest area. In these respects, future work will focus on spatial and temporal extent of study area and robust carbon stock estimation with various satellite images and estimation methods.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.15 no.2
• /
• pp.88-93
• /
• 2011

Purpose: As to analytical method of data, the AutoQUANT software in which it is used quantitative rating of the myocardial perfusion SPECT are reported that there is a difference. Therefore the measured value error of the mutual program is expected to be generated even if the quantitative analysis is made data of the same patient. The purpose of this study is to offer the comparative analysis of myocardial extract method in Quantitative Perfusion SPECT. Materials and methods: We analyzed the 51 patients who were examined by Tc-99m MIBI gated myocardial SPECT in nuclear medicine department of Pusan National University Hospital from June to December 2010(34 men, 17 women, mean age $66.5{\pm}9.9$). We acquired the extracted image in myocardial extract protocol. QPS program that uses the AutoQUANT software measured TID(Transient Ischemic Dilation), ESD(Extent of Stress Defect), SSS(Summed Stress Score). Then analyzed the results. Results: The correlation of appyling myocardial extract is TID(r=0.98), ESD(r=0.99), SSS(r=0.99). In the 95% confidence limit, there was no satistically significant difference(TID p=0.78, ESD p=0.31, SSS p=0.19). After blinding test with a physician for making a qualitative analysis, there was no difference. Conclusion: Quantitative indices in QPS program showed good correlation and the results showed no statistically signigicant difference. The variance between method was small. therefore, the functional parameters by each method can be used interchangeably. Also, we expect patient's satisfaction.

• Korean Journal of Veterinary Research
• /
• v.5 no.1
• /
• pp.97-123
• /
• 1965

Observations were made on the blood picture of total 196 heads of healthy Korean cattles, including 98 males and females in the purpose of determination of blood chemical values and their sex differences and seasonal variations during one year period from December, 1963 to November, 1964. The blood sampling were scheduled by random in four different seasons and the sample size of both sex included in each season were designated to be same size. The ranges, averages or mean values of the blood glucose, total serum protein, serum globulin, serum albumin, total non-protein nitrogen, blood urea nitrogn, total serum cholesterol, serum inorganic phosphorus and serum calcium were determined in this studies and their respective standard deviation, standard error of means, sex differences and seasonal variations were as follows. 1. The blood glucose values for the male ranged from 32.8 to 70.0 mg/100cc. with a mean of $49.781{\pm}0.823mg/100cc$; for the female the range was 32.0 to 64.0mg/100cc. with a mean of $47.235{\pm}0.782mg/100cc$. Sex difference showed significant at 5% level and seasonal variation was highly significant at 1% level. 2. The total serum protein values for the male ranged from 5.61 to 8.83 gm/100cc with a. mean of $7.366{\pm}0.062gm/100cc$; for the female ranged from 5.53 to 8. 43 gm/100cc. with a mean of $6.832{\pm}0.063gm/100cc$. Sex difference and seasonal variation was not significant. 3. The serum globulin values for the male ranged from 2.97 to 4.78 gm/100cc. with a mean of $3.961{\pm}0.039gm/100cc$.; for the female ranged from 2.87 to 4.41 gm/100cc. with a mean of $3.699{\pm}0.037gm/100cc$. Sex difference showed highly significant at 1% level and seasonal variation was not significant. 4. The serum albumin values for the male ranged from 2.58 to 4.21 gm/100cc. with a mean of $3.405{\pm}0.029gm/100cc$.; for the female ranged from 2.39 to 4.10 gm/100cc. with a mean of $3.204{\pm}0.031gm/100cc$. Sex difference showed highly significant at 1% level and seasonal variation was not significant. 5. The total non-protein nitrogan values for the male ranged from 19.1 to 44.8 gm/100cc. with a mean of $31.166{\pm}0.582mg/100cc$.; for the female the range was 15.2 to 50.5 mg/100cc. with a mean of $28.89.6{\pm}0.673mg/100cc$. Sex difference showed significant at 5% level and seasonal variation was highly significant at 1 % level. 6. The blood urea nitrogen values for the male ranged from 6.4 to 28.3 mg/100cc. with a mean of $13.371{\pm}0.466mg/100cc$.; for the female the range, was 6.0 to 26.9 mg/100cc. with a mean of $13.631{\pm}0.321mg/100cc$. Sex difference was not significant and seasonal variation showed highly significant at 1 % level. 7. The total serum cholesterol values for the male ranged from 60.0 to 238.6 mg/100cc. with a mean of $140.897{\pm}2.826mg/100cc$.; for the female ranged from 50.0 to 243.0 mg/100cc. with a mean of $124.840{\pm}3.553mg/100cc$. Sex difference and seasonal variation showed highly significant at 1% level. 8. The serum inorganic phosphorus values for the male ranged from 3.5 to 7.8 mg/100cc. with a mean of $5.426{\pm}0.096mg/100cc$.; for the female ranged from 3.1 to 8.8 mg/100cc. with a mean of $5.570{\pm}0.128mg/100cc$. Sex difference and seasonal variation showed no significant. 9. The serum calcium values for the male ranged from 7.8 to 12.8 mg/100cc. with a mean of $10.761{\pm}0.102mg/100cc$.; for the female ranged from 8.0 to 13.0 mg/100cc. with a mean of 10. $756{\pm}0.097mg/100cc$. Sex difference was not significant and seasonal variation showed highly significant at 1% level. 10. The age of test group ranged from 2 years to 6 years in both sex and the averageage were, $4.45{\pm}0.114$ years in male and $4.50{\pm}0116$ years in female. Sex difference and seasonal variation of age were not found to be significant.

• The Journal of Korean Academy of Prosthodontics
• /
• v.49 no.3
• /
• pp.197-205
• /
• 2011

Purpose: This study was to evaluate the accuracy of the implant torque controller used in dental clinics and to investigate whether it was applied appropriately. Materials and methods: Fifty dentists who work in dental clinics were enrolled in this study. Dental (implant) practice career, experience frequency of implant screw loosening and fracture, education of implant torque controller application and infection control methods were included in the survey. 25 Ncm and 30 Ncm of the tightening torque applied to the implant screw were measured by 50 clinicians. After measuring the torque value by using the torque controller, the torque mean according to where education about the implant torque controller was received was analyzed with independent t-test at the significance level of 0.05. Results: The torque controller used in private dental clinics showed 4.78% error ratio. When 50 dentists applied 25 Ncm to the implant screw was $29.0{\pm}8.4$ Ncm, and that in 30 Ncm was $34.3{\pm}9.1$ Ncm. Statistical significance was found between the group that was educated about implant torque application and the group that was not educated. Conclusion: During the prosthodontic treatment with implant, there was difference between actual applied torsion force and the amount torque controller indicated. Clinicians have to not only be well-informed about the accurate usage method of the torque controller, but also keep and manage the torque controller so as to maintain continuous and accurate torque values. Through this, it is considered to achieve clinical results to minimize problems of screw loosening or fracture.