• The Korean Journal of Nuclear Medicine
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• v.37 no.4
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• pp.235-244
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• 2003

Purpose: Attention deficit hyperactivity disorder (ADHD) has been known as psychiatric disorder in childhood associated with dopamine dysregulation. In present study, we investigated changes in dopamine transporter (DAT) density of the basal ganglias using I-123 N-(3-iodopropen-2-yl) -2-carbomethoxy-3beta-(4-chlorophenyl) tropane [I-123 IPT] SPECT in children with ADHD before and after methylphenidate treatment. Materials and Method: Nine drug-naive children with ADHD and seven normal children were included in the study. We peformed brain SPECT two hours after the intravenous administration of I-123 IPT and made both quantitative and qualitative analyses using the obtained SPECT data, which were reconstructed for the assessment of soecific/nonspecific DAT binding ratios in the basal ganglia. All children with ADHD reperformed [123I]IPT SPECT after treatment with methylphenidate(0.7mg/kg/d) during about 8 weeks. SPECT data reconstructed for the assessment of specific/nonspecific DAT binding ratio of the basal ganglia were compared between before and after treatment methylphenidate. We investigated correlation between the change of ADHD symptom severity assessed with ADHD rating scale-IV and specific/nonspecific DAT binding ratio of basal ganglia. Results: Children with ADHD had a significantly greater specificinonspecific DAT binding ratio of the basal ganglia comparing to normal children(Right : z = 2.057, p = 0.041 : Left : z : 2.096, p = 0.032). Under treatment with methylphenidate in all children with ADHD, specificinonspecific DAT binding ratio of both basal ganglia decreased significantly greater than before treatment with methylphenidate (Right : t = 3.239, p = 0.018 ; Left : t = 3.133, p = 0.020). However, no significant correlation between the change of ADHD symptom severity scores and specific/nonspecific DAT binding ratio of the basal ganglia were found. Conclusions: These findings support the complex dysregulation of the dopaminergic neurotransmitter system in children with ADHD.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.11
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• pp.783-789
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• 2011

Recently, auto-thermal thermophilic aerobic digestion (ATAD) has a great attention for destruction of wasted sludge biomass in wastewater treatment plant. Reduction of sludge concentration has been successfully achieved with pilot scale ATAD and ceramic filtration process in field condition. However, high concentration of COD, total nitrogen (TN) and total phosphorus (TP) was observed in filtrate, which should be treated before recirculation of filtrate to biological wastewater treatment plant. This study was focused on removal of nitrogen and phosphorus contained in the filtrate of ATAD, using struvite crystallization method. The effect of operational and environmental parameters (such as, N, P and Mg ion concentration and molar ratio, pH, reaction time, agitation strength, seed dosage, and reaction temperature) on the treatment of TN and TP with struvite crystallization were evaluated. Magnesium (as $MgCl_26H_2O$) and phosphorus (as $K_2HPO_4$) ions were, if necessary, added to increase nitrogen removal efficiency by the crystal formation. Average concentration of $NH_4^+-N$ and $PO_4^{3-}-P$ of the filtrate were 1716.5 mg/L and 325.5 mg/L, respectively. Relationship between removal efficiencies of nitrogen and phosphorus and molar ratios of $Mg^{2+}$ and $PO_4^{3-}-P$ to $NH_4^+-N$ was examined. Crystal formation and nitrogen removal efficiencies were significantly increased as increasing molar ratios of magnesium and phosphorus to nitrogen. As molar ratio of $Mg^{2+}:PO_4^{3-}-P:NH_4^+-N$ were maintained to 2 : 1 : 1 and 2 : 2 : 1, removal efficiencies of nitrogen and phosphorus were 71.6% and 99.9%, and 93.8% and 98.6%, respectively. However, the effect of reaction time, mixing intensity, seed dose and temperature on the struvite crystallization reaction was not significant, comparing to those of molar ratios. Settled sludge volume after struvite crystallization was observed to be reduced with increase of seed dose and to be increased at high temperature.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.2
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• pp.115-123
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• 2013

Stoker type incinerator is one of the most popular one used as municipal solid waste (MSW) incineration because, in general, it is quite suitable for large capacity and need no preprocessing facility. Nowadays, however, since the combustible portion of incoming MSW increases together with the decrease of the moisture content due to prohibition of directly burying food waste in landfill, the heating value of waste is remarkably increasing in comparison with the early stage of incinerator installation. Consequently, the increased heating value in incinerator operation causes a number of serious problems such as reduction of waste amount to be burned due to the boiler heat capacity together with the significant NO generation in high temperature environment. Therefore, in this study, a series of numerical simulation have been made as parameters of waste amount and the fraction of moisture in air stream in order to investigate optimal operating condition for the resolution of the problems associated with the high heating value of waste mentioned above. In specific, a detailed turbulent reaction flow field calculation with NO model was made for the full scale incinerator of D city. To this end, the injection method of moisturized air as oxidizer was intensively reviewed by the addition of moisture water amount from 10% and 20%. The calculation result, in general, showed that the reduction of maximum flame temperature appears consistently due to the combined effects of the increased specific heat of combustion air and vaporization heat by the addition of water moisture. As a consequence, the generation of NOx concentration was substantially reduced. Further, for the case of 20% moisture amount stream, the afterburner region is quite appropriate in temperature range for the operation of SNCR. This suggests the SNCR facility can be considered for reoperation. which is not in service at all due to the increased heating value of MSW.

• 대한공업교육학회지
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• v.31 no.2
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• pp.203-232
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• 2006

The purposes of this study are to examine the effects of learning, which was applied TRIZ's 40 inventive principles, on the improvement of learners' creativity and to offer basic information that would be necessary to study on Inventive Education in Technology Education. In order to achieve the purposes, objects were divided into two groups, experiment group(74 students) and control group(67 students), who were from B Middle school in Daejeon. Creativity Self-Assessment and Student Inventive Rating Scale were used as tools for research so that we could find the homogeneity in two groups. An applied design method was nonequivalent control group pretest-posttest design. This study was performed for 2 hours on the 1st and the 3rd Saturday in every month from the 3rd week of March, 2006 to the 3rd of July of 2006, and total researching period was 9 weeks. In that time, the students were required to learn 40 inventive principles. The results from this study are as below. (1) Applying TRIZ's 40 inventive principles had a positive effect on students' CQ(creative quotient), as influencing on the subordinate factors of creativity, such as, originality, germinal, trasformational, value, attraction, expressive power and organic systemicity. However it didn't have any effect on adequateness, properness, merit, complex and elegance. (2) Applying TRIZ's 40 inventive principles had a significant effect neither on CQ by sex, nor on the subordinate factors of creativity, except for originality and expressive power. Based on the results of the experiment, below suggestions were made to promote the application of TRIZ's 40 inventive principles to Technology Education. (1) Although this study was performed by using development activities, it is necessary to study more systemically to apply 40 inventive principles to regular subject in Technology Education. (2) As creativity was very important in Technology Education, there should be studies on the various types of inventive principles and techniques for Inventive Education in Technology Education.

• Journal of Intelligence and Information Systems
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• v.18 no.2
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• pp.157-175
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• 2012

It is difficult to evaluate the performance of process innovation of e-procurement which has large scale and complex processes. The existing evaluation methods for measuring the effects of process innovation have been mainly done with statistically quantitative methods by analyzing operational data or with qualitative methods by conducting surveys and interviews. However, these methods have some limitations to evaluate the effects because the performance evaluation of e-procurement process innovation should consider the interactions among participants who are active either directly or indirectly through the processes. This study considers the e-procurement process as a complex system and develops a simulation model based on MAS(Multi-Agent System) to evaluate the effects of e-procurement process innovation. Multi-agent based simulation allows observing interaction patterns of objects in virtual world through relationship among objects and their behavioral mechanism. Agent-based simulation is suitable especially for complex business problems. In this study, we used Netlogo Version 4.1.3 as a MAS simulation tool which was developed in Northwestern University. To do this, we developed a interaction model of agents in MAS environment. We defined process agents and task agents, and assigned their behavioral characteristics. The developed simulation model was applied to G2B system (KONEPS: Korea ON-line E-Procurement System) of Public Procurement Service (PPS) in Korea and used to evaluate the innovation effects of the G2B system. KONEPS is a successfully established e-procurement system started in the year 2002. KONEPS is a representative e-Procurement system which integrates characteristics of e-commerce into government for business procurement activities. KONEPS deserves the international recognition considering the annual transaction volume of 56 billion dollars, daily exchanges of electronic documents, users consisted of 121,000 suppliers and 37,000 public organizations, and the 4.5 billion dollars of cost saving. For the simulation, we analyzed the e-procurement of process of KONEPS into eight sub processes such as 'process 1: search products and acquisition of proposal', 'process 2 : review the methods of contracts and item features', 'process 3 : a notice of bid', 'process 4 : registration and confirmation of qualification', 'process 5 : bidding', 'process 6 : a screening test', 'process 7 : contracts', and 'process 8 : invoice and payment'. For the parameter settings of the agents behavior, we collected some data from the transactional database of PPS and some information by conducting a survey. The used data for the simulation are 'participants (government organizations, local government organizations and public institutions)', 'the number of bidding per year', 'the number of total contracts', 'the number of shopping mall transactions', 'the rate of contracts between bidding and shopping mall', 'the successful bidding ratio', and the estimated time for each process. The comparison was done for the difference of time consumption between 'before the innovation (As-was)' and 'after the innovation (As-is).' The results showed that there were productivity improvements in every eight sub processes. The decrease ratio of 'average number of task processing' was 92.7% and the decrease ratio of 'average time of task processing' was 95.4% in entire processes when we use G2B system comparing to the conventional method. Also, this study found that the process innovation effect will be enhanced if the task process related to the 'contract' can be improved. This study shows the usability and possibility of using MAS in process innovation evaluation and its modeling.

• Journal of Intelligence and Information Systems
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• v.19 no.2
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• pp.39-54
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• 2013

Recent explosive increase of electronic commerce provides many advantageous purchase opportunities to customers. In this situation, customers who do not have enough knowledge about their purchases, may accept product recommendations. Product recommender systems automatically reflect user's preference and provide recommendation list to the users. Thus, product recommender system in online shopping store has been known as one of the most popular tools for one-to-one marketing. However, recommender systems which do not properly reflect user's preference cause user's disappointment and waste of time. In this study, we propose a novel recommender system which uses data mining and multi-model ensemble techniques to enhance the recommendation performance through reflecting the precise user's preference. The research data is collected from the real-world online shopping store, which deals products from famous art galleries and museums in Korea. The data initially contain 5759 transaction data, but finally remain 3167 transaction data after deletion of null data. In this study, we transform the categorical variables into dummy variables and exclude outlier data. The proposed model consists of two steps. The first step predicts customers who have high likelihood to purchase products in the online shopping store. In this step, we first use logistic regression, decision trees, and artificial neural networks to predict customers who have high likelihood to purchase products in each product group. We perform above data mining techniques using SAS E-Miner software. In this study, we partition datasets into two sets as modeling and validation sets for the logistic regression and decision trees. We also partition datasets into three sets as training, test, and validation sets for the artificial neural network model. The validation dataset is equal for the all experiments. Then we composite the results of each predictor using the multi-model ensemble techniques such as bagging and bumping. Bagging is the abbreviation of "Bootstrap Aggregation" and it composite outputs from several machine learning techniques for raising the performance and stability of prediction or classification. This technique is special form of the averaging method. Bumping is the abbreviation of "Bootstrap Umbrella of Model Parameter," and it only considers the model which has the lowest error value. The results show that bumping outperforms bagging and the other predictors except for "Poster" product group. For the "Poster" product group, artificial neural network model performs better than the other models. In the second step, we use the market basket analysis to extract association rules for co-purchased products. We can extract thirty one association rules according to values of Lift, Support, and Confidence measure. We set the minimum transaction frequency to support associations as 5%, maximum number of items in an association as 4, and minimum confidence for rule generation as 10%. This study also excludes the extracted association rules below 1 of lift value. We finally get fifteen association rules by excluding duplicate rules. Among the fifteen association rules, eleven rules contain association between products in "Office Supplies" product group, one rules include the association between "Office Supplies" and "Fashion" product groups, and other three rules contain association between "Office Supplies" and "Home Decoration" product groups. Finally, the proposed product recommender systems provides list of recommendations to the proper customers. We test the usability of the proposed system by using prototype and real-world transaction and profile data. For this end, we construct the prototype system by using the ASP, Java Script and Microsoft Access. In addition, we survey about user satisfaction for the recommended product list from the proposed system and the randomly selected product lists. The participants for the survey are 173 persons who use MSN Messenger, Daum Caf$\acute{e}$, and P2P services. We evaluate the user satisfaction using five-scale Likert measure. This study also performs "Paired Sample T-test" for the results of the survey. The results show that the proposed model outperforms the random selection model with 1% statistical significance level. It means that the users satisfied the recommended product list significantly. The results also show that the proposed system may be useful in real-world online shopping store.

• Journal of Chest Surgery
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• v.38 no.2 s.247
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• pp.123-131
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• 2005

Background: The number of elderly patients undergoing coronary artery bypass grafting (CABG) is increasing. Elderly patients are at increased risk for a variety of perioperative complications and mortality. We identified determinants of operative complications and mortality in elderly patients undergoing CABG. Material and Method: Between January 1995 and July 2003, 91 patients older than 75 years underwent isolated CABG at Asan Medical Center. There were 67 men and 24 women with mean age of $77.0\pm2.4$ years. Thirty clinical or hemodynamic variables hypothesized as predictors of operative mortality were evaluated. Result: CABG was performed under emergency conditions in 5 patients. The internal thoracic artery was used in 85 patients and 10 patients received both internal thoracic arteries. The mean number of distal anastomosis was 3.7 per patient. Operative mortality was $3.3\%$. Twenty-two patients had at least one major postoperative complication. Low cardiac output syndrome was the most common complication, followed by reoperation for bleeding, pulmonary dysfunction, perioperative myocardial infarction, stroke, acute renal failure, ventricular arrhythmia, upper gastrointestinal bleeding, infection, and delayed sternal closure. None were the predictors of mortality. Renal failure, peripheral vascular disease, emergency operation, recent myocardial infarction, congestive heart failure, New York Heart Association (HYHA) class III or IV, Canadian Cardiovascular Society (CCS) angina scale III or IV, and low left ventricle ejection fraction below $40\%$ were univariate predictors of overall complications. Actuarial probability of survival was $94.9\%,\;89.8\%,\;and\;83.5\%$ at postoperative 1, 3 and 5 years respectively. During the follow-up period $93.3\%$ of patients were in NYHA class I, or II and $91.1\%$ were free from angina. Conclusion: Although operative complication is increased, CABG can be performed with an acceptable operative mortality and excellent late results in patients older than 75 years.

• Tunnel and Underground Space
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• v.22 no.4
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• pp.266-275
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• 2012

In this study, a method is devised to implement a supercritical $CO_2$ ($scCO_2$) injection environment on a laboratory scale and to investigate the effects of $scCO_2$ on the properties of rock specimens. Specimens of shale and sandstone normally constituting the cap rock and reservoir rock, respectively, were kept in a laboratory reactor chamber with $scCO_2$ for two weeks. From this stage, a chemical reaction between rock surface and the $scCO_2$ was induced. The effect of saline water was also investigated by comparing three conditions ($scCO_2$-rock, $scCO_2-H_2O$-rock and $scCO_2$-brine(1M)-rock). Finally, we checked the changes in the properties before and after the reaction by destructive and nondestructive testing procedures. The swelling of shale was a main concern in this case. The experimental results suggested that $scCO_2$ has a greater effect on the swelling of the shale than pure water and brine. It was also observed that the largest swelling displacement of shale occurred after a reaction with the $H_2O-scCO_2$ solution. The results of a series of the destructive and nondestructive tests indicate that although each of the property changes of the rock differed depending on the reaction conditions, the $H_2O-scCO_2$ solution had the greatest effect. In this study, shale was highly sensitive to the reaction conditions. These results provide fundamental information pertaining to the stability of $CO_2$ storage sites due to physical and chemical reactions between the rocks in these sites and $scCO_2$.

• Journal of Oriental Neuropsychiatry
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• v.16 no.1
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• pp.1-17
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• 2005

Objective : This empirical research is performed to recognize diagnostic concept, pattern identification, and clinical features of Hwa-byung. In other words, the aims of this research are to examine the differences of the diagnosis between Hwa-Byung and the other psychiatric disorders, and to find out pattern identification, and clinical characteristics of Hwa-Byung for prescriptions of this syndrome. Method : In the experiment, there were participated 30 patients who were met for our criterions according to HBDIS (Hwa-Byung Diagnostic interview Schedule). These patients were diagnosed as Axis1 according to criterions of DSM-IV with administering SCID-I. OMS-prime was utilized for finding out pattern identification of oriental medicine. Symptom Check List-90-Revision(SCL-90-R), Hemilton rating Scale for Depression(HRSD), Heart Rate Variability(HRV), and Digital Infrared Thermographic imaging(D.I.T.I.) were also utilized to discover clinical characteristics of Hwa-Byung Patients. Results : 1. Regarding Sex-ratio, male subjects were 3(10%), and female subjects are 27(90%). The age of subjects ranged from 22 year old to 75 $(51.87{\pm}11.04;\:Mean{\pm}SD)$ 2. In the results of diagnosis on the basis of DSM-IV, the 17(56.67%) patients were MOD (Major Depressive Disorder), the 5(16.67%) patients were USD (Undifferentiated Somatoform Disorder), the 4(13.33%) patients were Dysthymic Disorder, the 3(10%) patients were GAD (Generalized Anxiety Disorder), and the 1(3.33%) was Panic Disorder. Two of the patients who diagnosed as MOD were diagnosed as Panic Disorder too, and one of them was diagnosed as Pain Disorder too. 3. Regarding pattern identification, Hwa-Byung is positively correlated to deficiency of Heart(心). and then to stagnancy of Liver-Gall bladder. Hwa-Byung is correlated deficiency symptom-complex rather than excessiveness symptom-complex. That is also correlated positively to Pathological heat and fire. 4. In SCL90-R, the mean of PSDI was $(75.3{\pm}10.7;\:Mean{\pm}SD)$. The each mean of the other 11 factors was distributed between50-70. 5. The mean of HRSD was $(17.9{\pm}5.6;\:Mean{\pm}SD)$ in the entire subject's group. Then the group of MDD was $20.9{\pm}4.4$ and the group of USD was $12.0{\pm}4.8$ 6. In the results of HRV. the mean of TP is $972.4{\pm}1174(Mean{\pm}SD)$, this is lower than normal range 1000-200. The other factors were within normal range. Then, there were no significant differences between them (p<0.05). 7. The temperatures of each acupoint have significant differences between HNl(印堂) and PC6(內關), between CV17(顫中) and PC6(內關), between HN1(印堂) and CV8(神闕), between CV17(顫中) and CV8(神闕) in comparison with the average of body temperature in the use of D.I.T.I. (p<0.01) 8. In the analysis of correlation between SCL-90-R, HRSD, HRV. and D.I.T.I. there were no significant results. According to results that the correlation was analyzed with only the MDD group as subjects, there was negative correlation between RMSSD of HRV and HRSD, between LF of HRV and PDSIof SCL-90-R, and between LF/HF of HRV and ANX, PSY, and PDSI of SCL-90-R. Conclusion : In the observation of clinical features of 30 cases of Hwa-Byung patients by using diverse structured tests, there could make diverse diagnosis as depressive disorder, anxiety disorder, and Somatoform Disorder. Particularly. MDD was highly distributed. Considering oriental medicine's pattern identification of Hwa-Byung, this syndrome is related strongly to Heart, and there were demonstrated deficiency symptom-complex, and Pathological heat and fire. One of the limits of this study is lack of control subject's group, therefore, in the future study, it requires reexamination through a comparative research with these data to complete this study.

• The Korean Journal of Nuclear Medicine Technology
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• v.19 no.1
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• pp.30-36
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• 2015

Purpose Whole body bone scan, which makes up a largest percentage of nuclear medicine tests, has high sensitivity and resolution about bone lesion like osteomyelitis, fracture and the early detection of primary cancer. However, any standard for valuation has not yet been created except minimum factor. Therefore, in this study, we will analysis the method which show a quantitative evaluation index in whole body bone scan. Materials and Methods This study is conducted among 30 call patients, who visited the hospital from April to September 2014 with no special point of view about bone lesion, using GE INFINIA equipment. Enumerated data is measured mainly with patient's whole body count and lumbar vertabrae, and the things which include CNR (Contrast to Noise ratio), SNR (Signal to Noise ratio) are calculated according to the mean value signal and standard deviation of each lumbar vertabrae. In addition, the numerical value with the abdominal thickness is compared to each value by the change of scan speed and tissue equivalent material throughout the phantom examination, and compared with 1hours deleyed value. Completely, on the scale of ten, 2 reading doctors and 5 skilled radiologists with 5-years experience analysis the correlation between visual analysis with blind test and quantitative calculation. Results The whole body count and interest region count of patients have no significant correlation with visual analysis value throughout the blind test(P<0.05). There is definite correlation among CNR and SNR. In phantom examination, Value of the change was caused by the thickness of the abdomen and the scan speed. And The poor value of the image in the subject as a delay test patient could be confirmed that the increase tendency. Conclusion Now, a standard for valuation has not been created in whole body bone scan except minimum factor. In this study, we can verify the significant correlation with blind test using CNR and SNR and also assure that the scan speed is a important factor to influence the imagine quality from the value. It is possible to be some limit depending on the physiology function and fluid intake of patient even if we progress the evaluation in same condition include same injection amount, same scan speed and so on. However, that we prove the significant evaluation index by presenting quantitative calculation objectively could be considered academic value.