• Journal of Korean Library and Information Science Society
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• v.39 no.4
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• pp.51-69
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• 2008

This study tired to develop the web credibility evaluation model by calculating weighted values and sensitivities of indicators which presented on preceding researches using Analytic Hierarchy Process. "Expert Choice 2000" was used as the tool for analysing AHP. 25 experts are answered for this questionnaire who are selected by judgement sampling method, one of the non-probability sampling method. Also, sensitivity analyses was performed to graphically see how the alternatives change with respect to the importance of the indicators or sub-indicators. The main results are summarized as followings; i) importance analysis in first level factors: trust-worthiness(0,606), expertness(0.222), safety(0.173), ii) importance analysis in second level factors: trustfulness (0.519), reputation(0.087), usefulness (0.102), timeliness(0,093), competency(0.027), security(0.115), reliability(0,058). iii) some of the importance analysis in third level factors: the site provides comprehensive information that is attributed to a specific source(0.252), the site has articles that list citations and references(0.153), the site contains user opinions and reviews(0.072), etc. iv) sensitivity analyses showed that the importance of the indicators or sub-indicators are slightly changed with respect to the alternatives change.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.3
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• pp.161-171
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• 1970

1. The higher the temperature of the sea water, and the smaller the size of the oriental brown shrimp, the higher the feeding rate of the shrimp will be as long as the temperature ranges from $19^{\circ}\;to\;30^{\circ}C$, and each shrimp weighs from 1.6 to 14.9 grams. The average daily feeding rate is between 18 to 44 percent. 2. The nighttime feeding rate is always higher than the daytime feeding rate. However, the daytime feeding rate can be raised to from 22 to 37 percent of the daily feeding rate iii the non-sediment, dark or direct-sunshine-shielded conditions. Growth can thus be accelerated to that extent under such conditions. 3. When anchovy and short-necked clam meats were simultaneously used as food, a greater quantity of anchovy meat was consumed than short-necked clam meat both during the daytime and nighttime. When anchovy and short-necked clam meats were simultaneously given, the averaged daily feeding rates of anchovy and short-necked clam meats were 12.9 percent and 10.3 percent, respectively. 4. The following equation applies to the relationship between the freight of the oriental brown shrimp (W in grams) and their daily growth rate (DGR in percent): log DGR=0.7035-0.7864 log W. The daily growth rate is in inverse proportion to the size of the shrimp. 5. The efficiency of food conversion of the oriental brown shrimp fluctuates between 2.8 and 7.8 percent without extensive difference depending on the size of the shrimp. This was very small as compared with the corresponding figures so far known for fish and cuttlefish.

• Radiation Oncology Journal
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• v.30 no.4
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• pp.158-164
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• 2012

Purpose: To evaluated the patterns of failure, survival rate, treatment-related toxicity and prognostic factors in postoperative radiotherapy of patients with ependymoma. Materials and Methods: Thirty patients who underwent surgery and postoperative radiotherapy for ependymoma between the period of June 1994 and June 2008 were reviewed retrospectively. The age of patients ranged from 21 months to 66 years (median, 19 years). Seventeen patients had grade II ependymoma, and 13 had grade III anaplastic ependymoma according to the World Health Organization grading system. The postoperative irradiation was performed with 4 or 6 MV photon beam with median dose of 52.8 Gy (range, 45 to 63 Gy), and radiation field including 2 cm beyond the preoperative tumor volume. Median follow-up period was 51 months (range, 12 to 172 months). Results: Fourteen out of 30 (46.7%) patients experienced recurrence, and 12 of those died. Among those 14 patients who experienced recurrence, 11 were in-field and 3 were out-of-field recurrence. The 5-year overall survival (OS) and progression-free survival (PFS) rates were 66.7% and 56.1%, respectively. On univariate analysis, tumor grade was a statistically significant prognostic factor for OS and PFS. There were two complications after surgery and postoperative radiotherapy, including short stature and facial palsy on the left side. Conclusion: We observed good survival rates, and histologic grade was a prognostic factor affecting the OS and PFS. Almost all recurrence occurred in primary tumor site, thus we suggest further evaluation on intensity-modulated radiotherapy or stereotatic radiosurgery for high-risk patients such as who have anaplastic ependymoma.

• Korean Journal of Plant Resources
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• v.26 no.1
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• pp.36-43
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• 2013

Aralia elata Seem. have a typical traditional significance among the wild herbs traditionally. Edible shoots of A. elata will augment consumer's interest due to its high value functional value, eco-friendly and pesticide-free produce. A. elata's root, fruit and bark are used as material of hypoglycemic agent and medicine for diabetes, kidney trouble, acute hepatitis, rheumation arthritis, stomach cancer and gastroenteric trouble. Flavonoid glycoside compound which is separated from A. elata's shoot shows high antioxidative activity. Also, root's identified active materials of antimicrobial was reported to be produced as food preservative and handy antimicrobial. Therefore, this research investigated quantitative morphological characteristics of leaves, spine and bud in naturally dominated and introducted A. elata in south Korea and then considered its principal compound analysis(PCA) and classification analysis(CA) among the 6 improved cultivars and 19 clones. PCA results showed that it show 76% accumulated explanation from four PC. The A. elata clones were classified into five groups; the first group of 15 clones including Yeongok, the second group of 5 clones including Yeoju, the third group of Bonghwa, Ulleung, the fourth group of Yongmunsa, Boseong and the fifth group of Singu. The object of this study will give us invaluable information about breeding by selection of A. elata in south Korea.

• Membrane Journal
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• v.9 no.3
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• pp.157-162
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• 1999

In the crosslining reaction of poly(vinyl alcohoJ)(PVA) with sulfur-succinic acid which had been established in our previous work, reaction temperature, 15$0^{\circ}C$, was so high to collapse the pore struc¬tures in support membrane for the preparation of composite membrane. Therefore, the efforts have been focused on lowering of the reaction temperature to 100$^{\circ}$C by using a catalysis, HC!. The newly established crosslinking reaction was characterized through the analysis of the chemical and thermal properties. From these results, the optimum conditions for the membrane preparation couId be drawn as followings : (i) reac¬tion temperature, 100 $^{\circ}C$,(ii) reaction time, 90 min, (iii) the concentration of the catalysis (HCD, 1.5%. Com¬posite membranes were fabricated by coating a casting solution containing PYA, sulfur-succinic acid and HCl on a support membrane followed by crosslinking it at 10$0^{\circ}C$. The resulting membranes were applied to the pervaporation separation of methyl-tert-butyl ether(MTBE)/methanol (MeOH) mixtures at 30, 40, and 5O$^{\circ}C$. The flux of 5.09 g/$m^2$hr at 5O$^{\circ}C$ and the highest separation factor of 1622 were obtained, respectively.

• Korean Journal of Medicinal Crop Science
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• v.20 no.4
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• pp.231-237
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• 2012

These studies were conducted to provide basic information on Korean ginseng cultivars and breeding lines (Panax ginseng C. A. Mey.) and to identify the variations that can be utilized in ginseng breeding programs. The agronomic characteristics was used to clarify the genetic relationships among Korean ginseng cultivars and breeding lines and to classify them into distinct genetic groups. Angle of petiole and number of fibrous root showed a wide variation from $15.0{\sim}67.8^{\circ}$ and 0~5, respectively. The average plant length was 54.2cm with a range of 37.9~64.8cm and the average stem diameter was 5.6mm with a range of 4.0~7.5mm. The average stem length was 31.9cm with a range of 21.8~37.9cm and the average root weight was 38.1 g with a range of 23.0~52.0 g. The 24 Korean ginseng cultivars and breeding lines were classified into 4 groups based on agronomic characteristics using the complete linkage cluster analysis. The I, II, III and IV groups included the 60.8%, 7.4%, 13.1% and 8.7% of the cultivars and breeding lines, respectively. The breeding lines in group I could be characterized as the group with the highest growth characters and yield components, such as plant length, stem diameter and root weight. The root weight, the yield component, had highly significant positive correlations with stem diameter, plant length and stem length.

• The korean journal of orthodontics
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• v.39 no.2
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• pp.120-129
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• 2009

Objective: To estimate dental maturity using the Demirjian Index for the mandibular third molar and investigate the relationships between dental maturity and skeletal maturity among growing children. Methods: The samples were derived from panoramic, lateral cephalometric and hand-wrist radiographs of 270 female subjects registered as patients at the orthodontic department, dental hospital, Yonsei University. Dental maturity [Demirjian Index (DI)] and skeletal maturity [skeletal maturation indicators (SMIs)] and cervical vertebrae maturation indicators (CVMIs)] were estimated from these radiographs. Results: There was a significant correlation (r = 0.64) between SMIs and DI, and a similar correlation (r = 0.59) was observed between CVMIs and DI (p < 0.001). If DI was above Stage E, then the SMI was above Stage 10 and the CVMI was above Stage 5. There was a weak correlation (r = 0.26) between age at menarche and DI (p < 0.001). There was no significant difference in DI among Class I, II or III malocclusions. Conclusions: Dental maturity evaluation using the mandibular third molar will be an adjunctive tool in combination with cervical vertebrae and hand-wrist maturity evaluations.

• Journal of the Korea Society of Computer and Information
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• v.11 no.6 s.44
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• pp.87-97
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• 2006

This study aims to identify the effect that the perceived usefulness and perceived ease of use have on learner flow in e-learning community. Based on literature review and Technology Acceptance Model(TAM), a potential model and five hypotheses were suggested. Questionnaire was carried out among 62 members of one e-learning community for preparatory teacher Cronbach alpha of the questionnaire was.88. The collected data were analyzed through correlation analysis and path analysis. The results of this research are as follows. Three hypotheses were adopted: Perceived usefulness will affect on attitudinal flow, Perceived ease of use will affect on attitudinal flow. and Attitudinal flow will affect on behavioral flow. Two hypotheses were rejected;. Perceived usefulness will affect on perceived ease of use and Perceived ease of use will affect on behavioral flow. The model revised through the results of path analysis had good-fitness. That is. overall fit measures (RMSEA, CFI. NNFI). indexes that show the suitability of the model were quite good. Findings of this study suggested the important strategies for designing e-learning community in order to promote learner flow.

• Journal of Ecology and Environment
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• v.29 no.3
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• pp.287-293
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• 2006

We carried out pollen analysis and radiocarbon dating from sediments of Wangdeungjae moor (960 m a.s.l.) to clarify vegetation history of temperate broad-leaved deciduous forest zone of Mt. Jiri. Three local pollen zones and two sub-zones were recognized on the basis of variation in the palynofloral assemblage: I. Quercus zone (150-114 cm), II. Quercus-Pinus zone (114-43 cm): IIa. Quercus-Pinus subzone (114-83 cm), IIb. Quercus-Pinus-Herbs subzone (83-43 cm), III. Pinus-Quercus zone (43-27 cm). Radiocarbon date from sediment depth 111-116 cm was estimated $1,160{\pm}40yr$ B.P. From these results, overall vegetation around of Wangdeungjae moor and Mt. Jiri have changed from Q. mongolica dominant to steady decrease of Q. mongolica whereas steady increase of P. densiflora, finally abrupt increase of P. densiflora. 'Medieval Warm Period (MWP)' and 'Little Ice Age (LIA)' have not had an effect on change of vegetation around, at least, Mt. Jiri. But at maximum period of LIA, extension of grassland and steady increase of Pinus were recognized around the moor. After then, an abrupt increase of Pinus is supposed that vegetation change is reflected in human impact surging around foothills.

• KDI Journal of Economic Policy
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• v.34 no.4
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• pp.117-156
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• 2012

This paper decomposes and estimates trend/cyclical components of some key macro variables-GDP, inflation, and interest rate, using a simple DSGE model along with flexible trend specification. The extracted cyclical components of output and interest rate are similar to HP-filtered counterparts, despite some differences in persistence and volatility, while inflation resembles that from BK filtering. This implies that the usual practice of applying a single filtering method to the data of interest may be problematic. When the baseline model is extended to incorporate consumption habit and price indexation, habit turns out to be important in explaining the persistence of business cycles. Comparison of several alternative models shows that the usual practice of estimation of DSGE model using filtered data leads to biased results. Finally, various sensitivity analyses illustrate that (1) allowing for correlation between structural cyclical shocks and trend shocks and (2) including irregular components (in inflation rate) may deliver interesting/important implication for gap estimates.