• Journal of Information Technology Applications and Management
• /
• v.16 no.4
• /
• pp.205-222
• /
• 2009

Considering time-lag in the performance evaluation of information system (IS) investment is important because its effect reveals after certain period of time passed. Particularly it is more in the systems of e-government informatization projects which the amount of investment and the scale of business are huge. Many methods to solve this issue have been proposed such as system dynamics methods, simulations, structural equations etc. However, it is still difficult and unsolved problem because collecting practical data for time-lag analysis is very hard. In this paper, we analyze IS time-lag effect through factor analysis using the accumulated practical operational DB data. For the performance evaluation of the G4C system, the representative e-government web portal, we selected eleven factors reflecting time passing in G4C DB data. With these factors this paper conduct time-lag analysis in four view points. First, we conducted 'Stabilizing of G4C system' and got a result that IS is needed about three years for the stabilization. Second, we conducted 'Utilization of G4C system' and got a result that the utilization reaches appropriate level after in three years later after the introduction of G4C system. Third, we conducted 'Cost reduction effect' and got a result that cost reduction is stable in the third year after the introduction of G4C system. Lastly, we conducted 'System maturity effect' and got a result that the system reaches to the quality level that users expect after third to fourth years. According to the results of this research, we found that performance of IS improv continuously not immediately, and it needs three or four years of time-lag.

• Journal of applied mathematics & informatics
• /
• v.30 no.3_4
• /
• pp.531-540
• /
• 2012

An approximation for the number of customers at service facility in $M/G/c/K$ retrial queue is provided with the help of the approximations of ordinary $M/G/c/K$ loss system and ordinary $M/G/c$ queue. The interpolation between two ordinary systems is used for the approximation.

• Applied Chemistry for Engineering
• /
• v.5 no.6
• /
• pp.1044-1055
• /
• 1994

The preparation of ZrC/SiC mixed powders from $ZrSiO_4/C$ and $ZrSiO_4/Al/C$ systems was attempted in the temperature range below $1600^{\circ}C$ under Ar or $Ar/H_2$ gas flow(100-500ml/min). The formation mechanism and kinetics of ZrC/SiC were suggested and the resultant powders were characterized. In $ZrSiO_4/C$ system, ZrC and SiC were formed by competitive reaction of $ZrO_2(s)$ and SiO(g) with carbon at temperature higher than $1400^{\circ}C$. The apparent activation energy for the formation of ZrC was approximately 18.5kcal/mol($1400-1600^{\circ}C$). In $ZrSiO_4/Al/C$ system, ZrC was formed by reaction of ZrO(g) with Al(l, g) and carbon at temperature higher than $1200^{\circ}C$, and SiC was formed by reduction-carbonization of SiO(g) with Al(l, g) and carbon at temperature higher than $1300^{\circ}C$. The products obtained at $1600^{\circ}C$ for 5h consisted of ZrC with lattice constant of $4.679{\AA}$ and crystallite size of $640{\AA}$, and SiC with lattice constant of $4.135{\AA}$ and crystallize size of $500{\AA}$. And also, the mean particle size was about $21.8{\mu}m$.

• Journal of Ginseng Research
• /
• v.33 no.3
• /
• pp.229-233
• /
• 2009

The centrifugal coating granulating system, a new method of preparing red ginseng extract pills, has been developed. The red ginseng extract was first powdered with 85.5% of edible ethanol and dried for 3 to 4 hours at 50$^{\circ}C$. The powders were fed in chamber of centrifugal coating granulating system and then granulated, sequentially. The centrifugal system operated at 20 to 50$^{\circ}C$ of inlet temperature, 1 to 1,000 g/min of feeding speed, 60 to 70$^{\circ}C$ of atmosphere temperature of intake, 3.0 to 4.0 bar of spray atmosphere pressure, 1,000 to 1,500 rpm of centrifugal plate speed and 25 to 40$^{\circ}C$ of outlet temperature. The product yield was about 85% and preparation time was 7 to 8 hours. Especially, major ginsenoside components of red ginseng were not decomposed after processing of red ginseng extract pill.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.23 no.1
• /
• pp.147-153
• /
• 2011

The Pseudorabies (PR), also called Aujeszky's disease (AD), is an infectious viral disease caused by an alpha herpes virus and has domestic and wild pigs, as well as a wide range of domestic and wild animals, as the natural host. Pseudorabies virus (PRV) virions contain several envelope glycoproteins. Among them, gB, gC and gD are regarded as the major immunogenic proteins. We expressed these glycoproteins using the bacterial expression system and analyzed recombinant proteins. Expression of glycoproteins gC and gD were observed on SDS-PAGE or Western blot analysis, but gB was not. Optimal concentration of IPTG and inducing time were determined as 1.0 mM and 4 h, respectively, for the expression of both gC and gD in E. coli. A sodium dodecyl sulfate (SDS) was the most efficient detergent in solubilizing insoluble recombinant protein.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.24 no.1
• /
• pp.31-40
• /
• 2016

In this study, mesophilic anaerobic digestion of source separated food waste was carried out by leachate recirculation system and methane gas was produced. Two systems - system A and B were fabricated and placed within water bath to maintain $36^{\circ}C$. Each system was comprised of an anaerobic bioreactor and a leachate tank. Leachate in bioreactor was separated through the screen located at 30 mm above the bottom and a pump was installed to transfer collected leachate to the leachate tank. Everyday, 2.5 L of the leachate was pumped from the bioreactor to the leachate tank for 30 min and transferred leachate was pumped back to the top of the bioreactor for 30min, sequentially. Source separated food waste used for this experiment was washed by water before transferring to the laboratory. Transferred food waste was warmed to $36^{\circ}C$ before being fed to bioreactors. System A was fed to 49.1 g VS (Volatile Solids) and System B was fed to 54.0 g VS at every two weeks, respectively. $NH_4{^+}-N$ and salinity were monitored to see the inhibition toward anaerobic bioreaction and it was found that concentrations of these materials were not high enough to affect the bioreaction. Although the food waste was fed biweekly for 112 days and 140 days at system A and B, respectively, there was no sludge withdrawal from each system. Average methane productions rates were 0.439 L $CH_4/g$ VS and 0.368 L $CH_4/g$ VS for system A and B, respectively.

• Korean Journal of Mathematics
• /
• v.18 no.4
• /
• pp.473-487
• /
• 2010

We investigate the existence of multiple nontrivial solutions (${\xi}$, ${\eta}$) for perturbations $g_1$, $g_2$ of the harmonic system with Dirichlet boundary condition $${\Delta}^2{\xi}+c{\Delta}{\xi}=g_1(2{\xi}+3{\eta})\;in\;{\Omega}\\{\Delta}^2{\eta}+c{\Delta}{\eta}=g_2(2{\xi}+3{\eta})\;in\;{\Omega}$$ where we assume that ${\lambda}_1$ < $c$ < ${\lambda}_2$, $g^{\prime}_1({\infty})$, $g^{\prime}_2({\infty})$ are finite. We prove that the system has at least three solutions under some condition on $g$.

• Journal of dental hygiene science
• /
• v.22 no.3
• /
• pp.156-163
• /
• 2022

Background: This study attempted to apply resin infiltrant (RI) as a method to maintain the effect of tooth bleaching treatment and compared it with fluoride varnish (FV) or artificial saliva to evaluate the effect. Methods: Sixty healthy lozenge specimens were classified into five groups. Group 1 was the negative control group, and discoloration was induced after artificial saliva treatment of the tooth specimen (G1_S+C). Group 2 was a positive control group, in which pigmentation was induced after bleaching treatment and artificial saliva treatment (G2 _B+S+C). Coloration was induced in group 3 (experimental group 1) after bleaching treatment and artificial saliva treatment, followed by application of fluorine varnish (G3_B+FV+S+C). Coloration was induced in Group 4 (experimental group 2) after applying RI after bleaching treatment and artificial saliva treatment (G4_B+RI+S+C). Pigmentation was induced in group 5 (experimental group 3) after bleaching treatment and artificial saliva treatment, followed by acid treatment (etching) and treatment with RI (G5_B+E+RI+S+C). Coffee and wine were used to induce discoloration. The lightness value (L^*) of the CIE L^*a^*b^* color system was obtained by image analysis. Kruskal-Wallis H analysis was performed for the mean difference in L^* values by group. Results: When coloration was induced with coffee, there was no significant difference in L^* value between artificial saliva (G2 _B+S+C), FV (G3_B+FV+S+C), and RI (G4_B+RI+S+C, G5_B+E+RI+S+C) groups. There was no significant difference in L^* values between the artificial saliva (G2 _B+S+C), FV (G3_B+FV+S+C), and RI (G4_B+RI+S+C, G5_B+E+RI+S+C) groups, even in the case of wine induced coloration. Conclusion: It was confirmed that artificial saliva or RI treatment had similar effects to the FV previously used to maintain the effect of tooth bleaching treatment.

• Communications of the Korean Mathematical Society
• /
• v.13 no.4
• /
• pp.801-810
• /
• 1998

Let A(z), W(z) and C(z) be power series with operator coefficients such that W(z) = A(z)C(z). Let D(A) and D(C) be the state spaces of unitary linear systems whose transfer functions are A(z) and C(z) respectively. Then there exists a Krein space D which is the state space of unitary linear system with transfer function W(z). And the element of D is of the form (f(z) ＋ A(z)h(z), k(z) ＋ C＊(z)g(z)) where (f(z),g(z)) is in D(A) and (h(z),k(z)) is in D(C).

• Annals of Laboratory Medicine
• /
• v.38 no.6
• /
• pp.530-537
• /
• 2018

Background: Measurement of insulin and C-peptide concentrations is important for deciding whether insulin treatment is required in diabetic patients. We aimed to investigate the analytical performance of insulin and C-peptide assays using the Lumipulse G1200 system (Fujirebio Inc., Tokyo, Japan). Methods: We examined the precision, linearity, and cross-reactivity of insulin and C-peptide using five insulin analogues and purified proinsulin. A method comparison was conducted between the Lumipulse G1200 and Roche E170 (Roche Diagnostics, Mannheim, Germany) systems in 200 diabetic patients on insulin treatment. Reference intervals for insulin and C-peptide concentrations were determined in 279 healthy individuals. Results: For insulin and C-peptide assays, within-laboratory precision (% CV) was 3.78-4.14 and 2.89-3.35%, respectively. The linearity of the insulin assay in the range of 0-2,778 pmol/L was $R^2=0.9997$, and that of the C-peptide assay in the range of 0-10 nmol/L was $R^2=0.9996$. The correlation coefficient (r) between the Roche E170 and Lumipulse G1200 results was 0.943 (P <0.001) for insulin and 0.996 (P <0.001) for C-peptide. The mean differences in insulin and C-peptide between Lumipulse G1200 and the Roche E170 were 19.4 pmol/L and 0.2 nmol/L, respectively. None of the insulin analogues or proinsulin showed significant cross-reactivity with the Lumipulse G1200. Reference intervals of insulin and C-peptide were 7.64-70.14 pmol/L and 0.17-0.85 nmol/L, respectively. Conclusions: Insulin and C-peptide tests on the Lumipulse G1200 show adequate analytical performance and are expected to be acceptable for use in clinical areas.