• Journal of Soil and Groundwater Environment
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• v.6 no.3
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• pp.53-59
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• 2001

There is a lot of method to manage the insanitary landfill but vertical cutoff walls have been widespreadly used and were installed into the subsurface to act as a barrier to horizontal groundwater flow, The stabilized material such as specialized cement or mixed soil with additives has been generally applied for the materials of the deep soil mixing barrier in korea. The amount of the stabilized material is dependent on the field conditions, because the mixing ratio of the material and the field soil should achieve a requirement in the coefficient of permeability, lower than 1.0$\times$$10^{7}$cm/sec. This study determined the quantity and optimized function ratio of the stabilized material in the formation process of the mixed barrier that was added with stabilized material on the field soil classified into SW-SC under USCS (Unified Soil Classification System). After that the fly ash and lime were selected as an additives an that could improve the function of the stabilized material and then the method to improve the functional progress in the usage of putting into the stabilized material as an appropriate ratio was studied and reviewed. The author used the flexible-wall permeameter for measuring the permeability and unconfined compressive strength tester for compressive strength, and in the view of environmental engineering the absorption test of heavy metals and leaching test regulated by Korean Waste Management Act were performed. As the results, the suitable mixing ratio of the stabilized material in the deep soil mixing barrier was determined as 13 percent. To make workability easy, the ratio of stabilized material and water was proven to be 1 : 1.5. With the results, the range of the portion of the additives(fly ash : lime= 70 : 30) was proven to be 20-40% for improving the function of the stabilized material, lowering of permeability. In heavy metal absorption assessment of the mixing barrier system with the additives, the result of heavy metal absorption was proved to be almost same with the case of the original stabilized material; high removal efficiency of heavy metals. In addition, the leaching concentration of heavy metals from the leaching test for the environmental hazard assessment showed lower than the regulated criteria.

• Journal of Chest Surgery
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• v.31 no.9
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• pp.867-872
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• 1998

Background: The fixed dose regimen with activated coagulation time(ACT) is the most commonly employed method for determining the required dosage of heparin and protamine during cardiopulmonary bypass(CPB). Material and Method: We performed a prospective study on a fixed dose regimen for analyzing adequate dosages of heparin and protamine, the incidence of heparin resistance and heparin-induced thrombocyt openia, factors affecting ACT during CPB, and changes of ACT during aprotinin usage. 300 units/kg of heparin were administered to patients, and ACTs were measured after 5 mins. ACTs were checked at 10 mins and 30 mins after the onset of CPB, and then at 30 min intervals thereafter. If the measured ACT was under 400 secs, we added 100 units/kg of heparin. The heparin was reversed with 1 mg of protamine for each 100 units administered. If the measured ACT was longer than 130 secs 30 mins after protamine administration or if there was definitive evidence of a coagulation defect, we administered a further 0.5 mg/kg of protamine. Result: We studied 80 patients(50 adults and 30 children) who underwent open heart surgery(OHS) at Seoul National University Hospital. Preoperative ACT was 114.3${\pm}$19.3 secs in adults, and 119.5${\pm}$18.2 secs in children. There were no differences in preoperative ACT due to age, body weight, body surface area, or sex. The preoperative ACT was not influenced by a positive past history of OHS. Ten adults(20%) and 3 pediatric patients(10%) needed additional doses of heparin to maintain the ACT above 400 secs. Additional protamine administration was needed in 9 adults(18%) and 10 children(33%). Heparin resistance was found in only two adults. Heparin-induced thrombocytopenia was detected in 2 adults and 1 child. During CPB, ACT was prolonged. 12 adult patients received a low dose of aprotinin and showed longer celite activated ACT compared to the control group.The kaolin activated ACT showed a lower tendency than the celite activated ACT in aprotinin users. Conclusion: In conclusion, fixed dose regimen of heparin and protamine can be used without significant problems, but the incidence of need of additional dosage remains unsatisfactory.

• Journal of Chest Surgery
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• v.34 no.12
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• pp.901-908
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• 2001

Background : Coronary artery bypass graft(CABG) in patients with advanced left ventricular dysfunction has often been regarded as having high mortality rate, despite the great improvement in operative result of CABG. With recent advances in surgical technique and myocardial protection, surgical revascularization improved the symptom and long-term survival of these high risk patients more than the medical conservative treatment. Material and Methold : Clinical data of 31(4.1％) patients with preoperative ejection fraction less than 30% among 864 CABGs performed between January 1995 and March 1999 were retrospectively analyzed and pre- and postoperative changes of the ejection fraction on echocardiography were analyzed. There were 26 men and 5 women. The mean age was 60.7 years(range 41 to 72 years). History of myocardial infarction(30 cases, 98％) was the most common preoperative risk factor. There were seven irreversible myocardial infarction on thallium scan. Most patients had triple vessel diseases(26 cases, 84％) and first degree of Rentrop classification(16 cases, 52％) on coronary angiography. The mean number of distal anastomosis during CABG was per patient was 4.9${\pm}$0.8 sites in each patient. In addition to long saphenous veins, the internal mammary artery was used in 20 patients. Total bypass time was 244.7${\pm}$3.7 minutes(range, 117 to 567 minutes), and mean aortic cross-clamp time was 77.9 ${\pm}$ 1.6 minutes(range, 30 to 178 minutes). There were five other reparative procedures such as two left ventricular aneurysrmectomy, two mitral repair, and one aortic valve replacement. There were twelve postoperative complications such as three cardiac arrhythmia, two bleeding(re-operation), one delayed sternal closure, eleven usage of intra-aortic balloon counterpulsation for low cardiac output. Two patients died, postoperative mortality was 6.5% . Twenty-nine patients were relieved of chest pain and left ventricular ejection fraction after operation was significantly higher(38.5${\pm}$11.6%, p 0.001) as compared with preoperative left ventricular ejection fraction(25.3${\pm}$2.3%). The follow up period of out patient was 25. 3 months. Conclusion: In patients with coronary artery disease and advanced left ventricular dysfunction, coronary artery bypass grafting can be performed relatively safely with improvement in left ventricular function, but it will be necessary to study long term results.

• Korean Journal of Medicinal Crop Science
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• v.14 no.1
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• pp.1-7
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• 2006

This research was conducted to investigate the possibilities of usage of germinated-buckwheat (Fagopyrum esculentum $M{\ddot{o}}ench$) by examining antioxidative, antimicrobial and cytotoxic effects of extracts from different germinated root length of buckwheat. Antioxidant activity $(RC_{50})$ was shown higher in extracts of non-germinated seed $(50.41\;{\mu}g/mL)$ and root length 10 mm $(80.57\;{\mu}g/mL)$, 2 mm $(93.77\;{\mu}g/mL)$, 5 mm $(107.09\;{\mu}g/mL)$ than BHT $(163.96\;{\mu}g/mL)$ as a synthetic antioxidant. In antimicrobial activity, non-germinated and germinated seeds were formed inhibitory zone against S. aureus $(4{\sim}10\;mm)$, P. aeruginosa $(2{\sim}9\;mm)$ at the concentrations of $10{\sim}40\;mg/mL$ but B. subtilis, E. coli and S. typhimurium were not apparent antimicrobial activity. Extracts of germinated seed also decreased their antimicrobial activity compared to non-germinated seed extract. In addition, the growth of Calu-6 was inhibited of both 5 mm root length germinated and non-germinated seeds $(800\;{\mu}g/mL)$ as 95.12% and 87.15%, respectively, but these did not show any influence on cytotoxic effect against MCF-7 and Caco-2 cell lines. Extracts of 2 mm and 5 mm germinated seeds were also inhibited against Calu-6 and SNU-601 cell lines.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.4
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• pp.51-58
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• 2008

Purpose: This study was assessed to investigate adverse effect induced by overuse of disposable soft contact lenses (CL). Methods: Three disposable lenses (etafilcon A, hilabilcon A, and nelfilcon A) were applied to 19 normal subjects free from any eye diseases for either a single day or variable periods by when subjects complained any discomforts. On the first and last days, localizations of lens' center on corneal surface and blink rates were recorded at every case. Results: Among CL wearers, 10.5% and 47.4% of total subjects quit wearing on the second day and third day, respectively. The case of stopping disposable lens wear was continuously increased with extended hour of lens application. On fourth day, 70.2% of CL wearers reported severe discomforts such as redness, dryness, irritation, pain and blurred vision. When subjects stopped CL wear, decentration of lens from the center of cornea was observed when it compared to the case of single usage of disposable CL. Also about 80% of total subjects showed increased blink rate when CL were worn for more than 2 days. These changes in lens centration and blink rate were consistantly shown regardless of lens types. Conclusions: Blurred vision and acute/chronic discomforts could occur to CL wearers by decentration of lens and increased blink rate when CL were overused more than 2 days even the numbers of two parameters measured in this study were variable by each subject or lens types. Therefore, consideration of individual characteristics and lens types is critical to prevent adverse effects may induced by overusage of disposable lens.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.28 no.1
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• pp.35-42
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• 2018

Objectives: The objectives of this study are to research the usage characteristics of asbestos-containing building materials and to conduct exposure risk assessment by applying no. 2016-230 "Methods of Risk Assessment of Asbestos-Containing Buildings" from the Ministry of Environment. Methods: One hundred buildings located in the Seoul and Gyeonggi-Incheon area were chosen, with 29 in Seoul, 20 in Incheon, and 51 in Gyeonggi-do Province. The year of construction was divided between three buildings in the 1970s, 11 buildings in the 1980s, 42 buildings in the 1990s, and 44 buildings in the 2000s. The bulk samples were analyzed by using a polarizing microscope after a pre-process using a stereomicroscope in a hood with an HEPA filter. This study defined ACMs(asbestos-containing materials) as asbestos when the content percentage was over 1% in the analysis result. Methods and standards of risk assessment of asbestos-containing building materials were conducted by refering to no. 2016-230 "Method of Risk Assessment of Asbestos-Containing Buildings" from the Ministry of Environment. The risk of exposure to ACMs was rated by a score based on three categories(high, middle, low risk of asbestos exposure). Results: In this study, 30 of the 100 buildings and 36 of the 416 bulk samples(8.6%) were found to have had asbestos. Asbestos was detected at a high rate, in 18 out of 42, in buildings constructed in the 1990s and at the lowest rate(7 out of 44) for buildings constructed in the 2000s. As a result of the evaluation according to no. 2016-230 "Method of Risk Assessment of Asbestos-Containing Buildings" of the Ministry of Environment, the risk assessment level of two asbestos-containing building materials was found to be "Medium", and 28 buildings materials were found to be at the "Low" level. Conclusion: As asbestos is regulated by the government, it is required to conduct active management and implemention by introducing methods of risk assessment of asbestos exposure that are supported by data from various situations. In the case of buildings owned by individuals, building owners should be aware of the risk of exposure to asbestos.

• Childhood Kidney Diseases
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• v.9 no.1
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• pp.21-30
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• 2005

Purpose : Metabolic bone diseases have been mai or problems in children with renal diseases and steroid treatment is the main precipitating factor reducing bone mineral density(BMD). This study was performed to assess the prevalence of osteoporosis and to evaluate the clinical factors associated with decreased BMD in children with renal diseases. Methods : Forty-four children with renal diseases who were diagnosed at the Pediatric no phrology division of Ajou University hospital since Oct. 1994 were included. Using a new quantitative ultrasound device, BMD and the prevalence of osteoporosis were evaluated. The clinical and serological data were analyzed in association with decreased BMD. Results : A total of 44 patients were evaluated. The age at initial diagnosis was 6.7$\pm$4.2 years. At the time of evaluation, the chronological and bone age was 9.3$\pm$4.2 years and 8.2 $\pm$ 4.6 years, respectively. The renal diseases included nephrotic syndrome 24(54.5%), Henoch Schonlein purpura nephritis 7(15.9%), IgA nephropathy 6(13.9%), reflux nephropathy(RN) 2 (4.5%), and other renal disease 5(%). The prevalence of osteoporosis was 11%. There was no difference in the clinical factors between the long-term and the short-term treated steroid groups. Conclusion : The prevalence of osteoporosis was 12% in 44 children with renal diseases No significant factor was found in association with decreased BMD and there was no relationship between osteoporosis and steroid usage duration or cumulative dose. A new quantitative ultrasound, which is relatively easy to perform, especially in children, is expected to be in common use and will enable clinicians to evaluate metabolic bone disorders with ease.

• Journal of Life Science
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• v.22 no.3
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• pp.407-416
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• 2012

In this study, we purified the extracts from the seeds and the roots of various plant species, including Q. acutissima, C. lanceolata, P. mirifica, P. bambusoides, and S. repens, and then investigated the effects of these extracts on cell growth and fat accumulation in adipocytes. We found that the extracts purified from Q. acutissima, C. lanceolata, P. mirifica, P. bambusoides, and S. repens more effectively increased the cell growth, as well as promoting the fat accumulation in adipocytes to a greater extent, than other extracts in vitro. Therefore, we made breast packs containing these effective extracts, and then investigated whether they were effective in enhancing the elasticity and volume of women's breasts. The measurements of breast elasticity and size revealed that the breast packs efficiently increased the elasticity and size of women's breasts. Furthermore, evaluation of the questionnaires related to usage of the breast packs indicated great satisfaction in terms of the lift, firmness, and elasticity of breasts. In conclusion, extracts purified from Q. acutissima, C. lanceolata, P. mirifica, P. bambusoides, and S. repens leading to cell growth and fat accumulation in adipocytes can effectively contribute to improving the elasticity and size of women's breasts.

• Asia pacific journal of information systems
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• v.20 no.1
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• pp.81-99
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• 2010

Lately, in consumers' markets the number of new items is rapidly increasing at an overwhelming rate while consumers have limited access to information about those new products in making a sensible, well-informed purchase. Therefore, item providers and customers need a system which recommends right items to right customers. Also, whenever new items are released, for instance, the recommender system specializing in new items can help item providers locate and identify potential customers. Currently, new items are being added to an existing system without being specially noted to consumers, making it difficult for consumers to identify and evaluate new products introduced in the markets. Most of previous approaches for recommender systems have to rely on the usage history of customers. For new items, this content-based (CB) approach is simply not available for the system to recommend those new items to potential consumers. Although collaborative filtering (CF) approach is not directly applicable to solve the new item problem, it would be a good idea to use the basic principle of CF which identifies similar customers, i,e. neighbors, and recommend items to those customers who have liked the similar items in the past. This research aims to suggest a hybrid recommendation procedure based on the preference boundary of target customer. We suggest the hybrid recommendation procedure using the preference boundary in the feature space for recommending new items only. The basic principle is that if a new item belongs within the preference boundary of a target customer, then it is evaluated to be preferred by the customer. Customers' preferences and characteristics of items including new items are represented in a feature space, and the scope or boundary of the target customer's preference is extended to those of neighbors'. The new item recommendation procedure consists of three steps. The first step is analyzing the profile of items, which are represented as k-dimensional feature values. The second step is to determine the representative point of the target customer's preference boundary, the centroid, based on a personal information set. To determine the centroid of preference boundary of a target customer, three algorithms are developed in this research: one is using the centroid of a target customer only (TC), the other is using centroid of a (dummy) big target customer that is composed of a target customer and his/her neighbors (BC), and another is using centroids of a target customer and his/her neighbors (NC). The third step is to determine the range of the preference boundary, the radius. The suggested algorithm Is using the average distance (AD) between the centroid and all purchased items. We test whether the CF-based approach to determine the centroid of the preference boundary improves the recommendation quality or not. For this purpose, we develop two hybrid algorithms, BC and NC, which use neighbors when deciding centroid of the preference boundary. To test the validity of hybrid algorithms, BC and NC, we developed CB-algorithm, TC, which uses target customers only. We measured effectiveness scores of suggested algorithms and compared them through a series of experiments with a set of real mobile image transaction data. We spilt the period between 1st June 2004 and 31st July and the period between 1st August and 31st August 2004 as a training set and a test set, respectively. The training set Is used to make the preference boundary, and the test set is used to evaluate the performance of the suggested hybrid recommendation procedure. The main aim of this research Is to compare the hybrid recommendation algorithm with the CB algorithm. To evaluate the performance of each algorithm, we compare the purchased new item list in test period with the recommended item list which is recommended by suggested algorithms. So we employ the evaluation metric to hit the ratio for evaluating our algorithms. The hit ratio is defined as the ratio of the hit set size to the recommended set size. The hit set size means the number of success of recommendations in our experiment, and the test set size means the number of purchased items during the test period. Experimental test result shows the hit ratio of BC and NC is bigger than that of TC. This means using neighbors Is more effective to recommend new items. That is hybrid algorithm using CF is more effective when recommending to consumers new items than the algorithm using only CB. The reason of the smaller hit ratio of BC than that of NC is that BC is defined as a dummy or virtual customer who purchased all items of target customers' and neighbors'. That is centroid of BC often shifts from that of TC, so it tends to reflect skewed characters of target customer. So the recommendation algorithm using NC shows the best hit ratio, because NC has sufficient information about target customers and their neighbors without damaging the information about the target customers.

• Asia pacific journal of information systems
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• v.23 no.4
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• pp.103-128
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• 2013

When a consumer needs a product or service and multiple sellers are available online, the process of selecting a seller to buy online from is complex since the process involves many behavioral dimensions that have to be taken into account. As a part of this selection process, consumers may set minimum trust expectation that can be used to screen out less trustworthy sellers. In the previous research, the level of consumers' trust expectation has been anchored on two important factors: product involvement and perceived risk. Product involvement refers to the extent to which a consumer perceives a specific product important. Thus, the higher product involvement may result in the higher trust expectation in sellers. On the other hand, other related studies found that when consumers perceived a higher level of risk (e.g., credit card fraud risk), they set higher trust expectation as well. While abundant research exists addressing the relationship between product involvement and perceived risk, little attention has been paid to the integrative view of the link between the two constructs and their impacts on the trust expectation. The present paper is a step toward filling this research gap. The purpose of this paper is to understand the process by which a consumer chooses an online merchant by examining the relationships among product involvement, perceived risk, trust expectation, and intention to buy from an e-tailer. We specifically focus on the mediating role of perceived risk in the relationships between enduring product involvement and the trust expectation. That is, we question whether product involvement affects the trust expectation directly without mediation or indirectly mediated by perceived risk. The research model with four hypotheses was initially tested using data gathered from 635 respondents through an online survey method. The structural equation modeling technique with partial least square was used to validate the instrument and the proposed model. The results showed that three out of the four hypotheses formulated were supported. First, we found that the intention to buy from a digital storefront is positively and significantly influenced by the trust expectation, providing support for H4 (trust expectation ${\rightarrow}$ purchase intention). Second, perceived risk was found to be a strong predictor of trust expectation, supporting H2 as well (perceived risk ${\rightarrow}$ trust expectation). Third, we did not find any evidence of direct influence of product involvement, which caused H3 to be rejected (product involvement ${\rightarrow}$ trust expectation). Finally, we found significant positive relationship between product involvement and perceived risk (H1: product involvement ${\rightarrow}$ perceived risk), which suggests that the possibility of complete mediation of perceived risk in the relationship between enduring product involvement and the trust expectation. As a result, we conducted an additional test for the mediation effect by comparing the original model with the revised model without the mediator variable of perceived risk. Indeed, we found that there exists a strong influence of product involvement on the trust expectation (by intentionally eliminating the variable of perceived risk) that was suppressed (i.e., mediated) by the perceived risk in the original model. The Sobel test statistically confirmed the complete mediation effect. Results of this study offer the following key findings. First, enduring product involvement is positively related to perceived risk, implying that the higher a consumer is enduringly involved with a given product, the greater risk he or she is likely to perceive with regards to the online purchase of the product. Second, perceived risk is positively related to trust expectation. A consumer with great risk perceptions concerning the online purchase is likely to buy from a highly trustworthy online merchant, thereby mitigating potential risks. Finally, product involvement was found to have no direct influence on trust expectation, but the relationship between the two constructs was indirect and mediated by the perceived risk. This is perhaps an important theoretical integration of two separate streams of literature on product involvement and perceived risk. The present research also provides useful implications for practitioners as well as academicians. First, one implication for practicing managers in online retail stores is that they should invest in reducing the perceived risk of consumers in order to lower down the trust expectation and thus increasing the consumer's intention to purchase products or services. Second, an academic implication is that perceived risk mediates the relationship between enduring product involvement and trust expectation. Further research is needed to elaborate the theoretical relationships among the constructs under consideration.